A central processing unit ( CPU ), also called a central processor , main processor , or just processor , is the most important processor in a given computer . Its electronic circuitry executes instructions of a computer program , such as arithmetic , logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs).
192-708: Pentium 4 is a series of single-core CPUs for desktops , laptops and entry-level servers manufactured by Intel . The processors were shipped from November 20, 2000 until August 8, 2008. All Pentium 4 CPUs are based on the NetBurst microarchitecture, the successor to the P6 . The Pentium 4 Willamette (180 nm) introduced SSE2 , while the Prescott (90 nm) introduced SSE3 and later 64-bit technology. Later versions introduced Hyper-Threading Technology (HTT). The first Pentium 4-branded processor to implement 64-bit
384-488: A TDP of 86 W. The D0 stepping in late 2006 reduced this to 65 watts. It has a 65 nm core and features the same 31-stage pipeline as Prescott, 800 MT/s FSB, Intel 64 , Hyper-Threading , but no Virtualization Technology. As with Prescott 2M, Cedar Mill also has a 2 MB L2 cache. Intel initially announced four VT-x enabled Cedar Mill processors with model numbers 633 to 663, but these were later cancelled and replaced by models 631 to 661 without VT-x,
576-456: A buffer overflow to get executed. Models supporting XD bit include the 5x0J and 5x1 series as well as the low-end 5x5J and 5x6. The Prescott processors are the first to support SSE3 , along with all Pentium D processors. Intel, by the first quarter of 2005, released a new Prescott core with 6x0 numbering, codenamed Prescott 2M. It is also sometimes known by the name of its Xeon derivative, Irwindale. It features Hyper-Threading, Intel 64 ,
768-488: A technology node or process node , designated by the process' minimum feature size in nanometers (or historically micrometers ) of the process's transistor gate length, such as the " 90 nm process ". However, this has not been the case since 1994, and the number of nanometers used to name process nodes (see the International Technology Roadmap for Semiconductors ) has become more of
960-508: A wafer , typically made of pure single-crystal semiconducting material. Silicon is almost always used, but various compound semiconductors are used for specialized applications. The fabrication process is performed in highly specialized semiconductor fabrication plants , also called foundries or "fabs", with the central part being the " clean room ". In more advanced semiconductor devices, such as modern 14 / 10 / 7 nm nodes, fabrication can take up to 15 weeks, with 11–13 weeks being
1152-530: A 20 μm process before gradually scaling to a 10 μm process over the next several years. Many early semiconductor device manufacturers developed and built their own equipment such as ion implanters. In 1963, Harold M. Manasevit was the first to document epitaxial growth of silicon on sapphire while working at the Autonetics division of North American Aviation (now Boeing ). In 1964, he published his findings with colleague William Simpson in
1344-612: A Pentium 4 580, clocked at 4 GHz. The E-series Prescott, as well as the low-end 517 and 524, incorporates Hyper-Threading in order to speed up some processes that use multithreaded software, such as video editing. The Prescott microarchitecture was designed to support Intel 64, Intel's implementation of the AMD-developed x86-64 64-bit extensions to the x86 architecture, but the initial models shipped with their 64-bit capability disabled. Intel stated that it did not intend to release 64-bit CPUs in retail channels, instead releasing
1536-402: A cache had only one level of cache; unlike later level 1 caches, it was not split into L1d (for data) and L1i (for instructions). Almost all current CPUs with caches have a split L1 cache. They also have L2 caches and, for larger processors, L3 caches as well. The L2 cache is usually not split and acts as a common repository for the already split L1 cache. Every core of a multi-core processor has
1728-470: A chip (SoC). Early computers such as the ENIAC had to be physically rewired to perform different tasks, which caused these machines to be called "fixed-program computers". The "central processing unit" term has been in use since as early as 1955. Since the term "CPU" is generally defined as a device for software (computer program) execution, the earliest devices that could rightly be called CPUs came with
1920-449: A code from the control unit indicating which operation to perform. Depending on the instruction being executed, the operands may come from internal CPU registers , external memory, or constants generated by the ALU itself. When all input signals have settled and propagated through the ALU circuitry, the result of the performed operation appears at the ALU's outputs. The result consists of both
2112-590: A comparable or better level than their synchronous counterparts, it is evident that they do at least excel in simpler math operations. This, combined with their excellent power consumption and heat dissipation properties, makes them very suitable for embedded computers . Many modern CPUs have a die-integrated power managing module which regulates on-demand voltage supply to the CPU circuitry allowing it to keep balance between performance and power consumption. Semiconductor fabrication Semiconductor device fabrication
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#17327728099092304-412: A data word, which may be stored in a register or memory, and status information that is typically stored in a special, internal CPU register reserved for this purpose. Modern CPUs typically contain more than one ALU to improve performance. The address generation unit (AGU), sometimes also called the address computation unit (ACU), is an execution unit inside the CPU that calculates addresses used by
2496-458: A dedicated L2 cache and is usually not shared between the cores. The L3 cache, and higher-level caches, are shared between the cores and are not split. An L4 cache is currently uncommon, and is generally on dynamic random-access memory (DRAM), rather than on static random-access memory (SRAM), on a separate die or chip. That was also the case historically with L1, while bigger chips have allowed integration of it and generally all cache levels, with
2688-564: A global clock signal. Two notable examples of this are the ARM compliant AMULET and the MIPS R3000 compatible MiniMIPS. Rather than totally removing the clock signal, some CPU designs allow certain portions of the device to be asynchronous, such as using asynchronous ALUs in conjunction with superscalar pipelining to achieve some arithmetic performance gains. While it is not altogether clear whether totally asynchronous designs can perform at
2880-460: A hundred or more gates, was to build them using a metal–oxide–semiconductor (MOS) semiconductor manufacturing process (either PMOS logic , NMOS logic , or CMOS logic). However, some companies continued to build processors out of bipolar transistor–transistor logic (TTL) chips because bipolar junction transistors were faster than MOS chips up until the 1970s (a few companies such as Datapoint continued to build processors out of TTL chips until
3072-481: A marketing term that has no standardized relation with functional feature sizes or with transistor density (number of transistors per unit area). Initially transistor gate length was smaller than that suggested by the process node name (e.g. 350 nm node); however this trend reversed in 2009. Feature sizes can have no connection to the nanometers (nm) used in marketing. For example, Intel's former 10 nm process actually has features (the tips of FinFET fins) with
3264-543: A maximum of 3.8 GHz. Intel had not anticipated a rapid upward scaling of transistor power leakage that began to occur as the die reached the 90 nm lithography and smaller. This new power leakage phenomenon, along with the standard thermal output, created cooling and clock scaling problems as clock speeds increased. Reacting to these unexpected obstacles, Intel attempted several core redesigns ( Prescott most notably) and explored new manufacturing technologies, such as using multiple cores, increasing FSB speeds, increasing
3456-411: A memory management unit, translating logical addresses into physical RAM addresses, providing memory protection and paging abilities, useful for virtual memory . Simpler processors, especially microcontrollers , usually don't include an MMU. A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from
3648-538: A modest but respectable rate, handicapped somewhat by the requirement for relatively fast yet expensive Rambus Dynamic RAM ( RDRAM ). The Pentium III remained Intel's top selling processor line, with the Athlon also selling slightly better than the Pentium 4. While Intel bundled two RDRAM modules with each boxed Pentium 4, it did not facilitate Pentium 4 sales and was not considered a true solution by many. In January 2001,
3840-494: A new core codenamed Northwood at speeds of 1.6 GHz, 1.8 GHz, 2 GHz and 2.2 GHz. Northwood (product code 80532) combined an increase in the L2 cache size from 256 KB to 512 KB (increasing the transistor count from 42 million to 55 million) with a transition to a new 130 nm fabrication process. Making the processor out of smaller transistors means that it can run at higher clock speeds and produce less heat. In
4032-459: A number that identifies the address of the next instruction to be fetched. After an instruction is fetched, the PC is incremented by the length of the instruction so that it will contain the address of the next instruction in the sequence. Often, the instruction to be fetched must be retrieved from relatively slow memory, causing the CPU to stall while waiting for the instruction to be returned. This issue
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#17327728099094224-543: A semiconductor device might not need all techniques. Equipment for carrying out these processes is made by a handful of companies . All equipment needs to be tested before a semiconductor fabrication plant is started. These processes are done after integrated circuit design . A semiconductor fab operates 24/7 and many fabs use large amounts of water, primarily for rinsing the chips. Additionally steps such as Wright etch may be carried out. When feature widths were far greater than about 10 micrometres , semiconductor purity
4416-419: A semiconductor fabrication facility are required to wear cleanroom suits to protect the devices from contamination by humans. To increase yield, FOUPs and semiconductor capital equipment may have a mini environment with ISO class 1 level of dust, and FOUPs can have an even cleaner micro environment. FOUPs and SMIF pods isolate the wafers from the air in the cleanroom, increasing yield because they reduce
4608-418: A semiconductor manufacturing process. Many semiconductor devices are designed in sections called cells, and each cell represents a small part of the device such as a memory cell to store data. Thus F is used to measure the area taken up by these cells or sections. A specific semiconductor process has specific rules on the minimum size (width or CD/Critical Dimension) and spacing for features on each layer of
4800-416: A single IC chip. Microprocessor chips with multiple CPUs are called multi-core processors . The individual physical CPUs, called processor cores , can also be multithreaded to support CPU-level multithreading. An IC that contains a CPU may also contain memory , peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on
4992-478: A still slower 1.3 GHz model was added to the range, but over the next twelve months, Intel gradually started reducing AMD's leadership in performance. In April 2001 a 1.7 GHz Pentium 4 was launched, the first model to provide performance clearly superior to the old Pentium III. July saw 1.6 and 1.8 GHz models and in August 2001, Intel released 1.9 and 2 GHz Pentium 4s. In the same month, they released
5184-476: A targeted speed boost the double size cache was intended to provide the same space and hence performance for 64-bit mode operations, due to the doubled word size compared to 32-bit mode. On November 14, 2005, Intel released Prescott 2M processors with VT ( Virtualization Technology, codenamed Vanderpool) enabled. Intel only released two models of this Prescott 2M category: 662 and 672, running at 3.6 GHz and 3.8 GHz, respectively. The final revision of
5376-554: A time. Some CPU architectures include multiple AGUs so more than one address-calculation operation can be executed simultaneously, which brings further performance improvements due to the superscalar nature of advanced CPU designs. For example, Intel incorporates multiple AGUs into its Sandy Bridge and Haswell microarchitectures , which increase bandwidth of the CPU memory subsystem by allowing multiple memory-access instructions to be executed in parallel. Many microprocessors (in smartphones and desktop, laptop, server computers) have
5568-446: A useful computer requires thousands or tens of thousands of switching devices. The overall speed of a system is dependent on the speed of the switches. Vacuum-tube computers such as EDVAC tended to average eight hours between failures, whereas relay computers—such as the slower but earlier Harvard Mark I —failed very rarely. In the end, tube-based CPUs became dominant because the significant speed advantages afforded generally outweighed
5760-439: A very small number of ICs; usually just one. The overall smaller CPU size, as a result of being implemented on a single die, means faster switching time because of physical factors like decreased gate parasitic capacitance . This has allowed synchronous microprocessors to have clock rates ranging from tens of megahertz to several gigahertz. Additionally, the ability to construct exceedingly small transistors on an IC has increased
5952-472: A wafer box or a wafer carrying box. In semiconductor device fabrication, the various processing steps fall into four general categories: deposition, removal, patterning, and modification of electrical properties. Modification of electrical properties now also extends to the reduction of a material's dielectric constant in low-κ insulators via exposure to ultraviolet light in UV processing (UVP). Modification
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6144-408: A wafer will be processed by a particular machine in a processing step during manufacturing. Process variability is a challenge in semiconductor processing, in which wafers are not processed evenly or the quality or effectiveness of processes carried out on a wafer are not even across the wafer surface. Wafer processing is separated into FEOL and BEOL stages. FEOL processing refers to the formation of
6336-587: A width of 7 nm, so the Intel 10 nm process is similar in transistor density to TSMC 's 7 nm process . As another example, GlobalFoundries' 12 and 14 nm processes have similar feature sizes. In 1955, Carl Frosch and Lincoln Derick, working at Bell Telephone Laboratories , accidentally grew a layer of silicon dioxide over the silicon wafer, for which they observed surface passivation effects. By 1957 Frosch and Derick, using masking and predeposition, were able to manufacture silicon dioxide transistors;
6528-531: Is also known as organosilicate glass (OSG). The Prescott was first fabricated at the D1C development fab and was later moved to F11X production fab. Originally, Intel released two Prescott lines on Socket 478: the E-series, with an 800 MT/s FSB and Hyper-Threading support, and the low-end A-series, with a 533 MT/s FSB and Hyper-Threading disabled. LGA 775 Prescott CPUs use a rating system, labeling them as
6720-400: Is defined by the CPU's instruction set architecture (ISA). Often, one group of bits (that is, a "field") within the instruction, called the opcode, indicates which operation is to be performed, while the remaining fields usually provide supplemental information required for the operation, such as the operands. Those operands may be specified as a constant value (called an immediate value), or as
6912-788: Is deposited. Once the epitaxial silicon is deposited, the crystal lattice becomes stretched somewhat, resulting in improved electronic mobility. Another method, called silicon on insulator technology involves the insertion of an insulating layer between the raw silicon wafer and the thin layer of subsequent silicon epitaxy. This method results in the creation of transistors with reduced parasitic effects . Semiconductor equipment may have several chambers which process wafers in processes such as deposition and etching. Many pieces of equipment handle wafers between these chambers in an internal nitrogen or vacuum environment to improve process control. Wet benches with tanks containing chemical solutions were historically used for cleaning and etching wafers. At
7104-401: Is determined by the width of the smallest lines that can be patterned in a semiconductor fabrication process, this measurement is known as the linewidth. Patterning often refers to photolithography which allows a device design or pattern to be defined on the device during fabrication. F is used as a measurement of area for different parts of a semiconductor device, based on the feature size of
7296-418: Is difficult to quantify due to dependence on the benchmark application's instruction mix, clock speed is a simple measurement yielding a single absolute number. Unsophisticated buyers would simply consider the processor with the highest clock speed to be the best product, and the Pentium 4 had the fastest clock speed. Because AMD's processors had slower clock speeds, it countered Intel's marketing advantage with
7488-403: Is frequently achieved by oxidation , which can be carried out to create semiconductor-insulator junctions, such as in the local oxidation of silicon ( LOCOS ) to fabricate metal oxide field effect transistors . Modern chips have up to eleven or more metal levels produced in over 300 or more sequenced processing steps. A recipe in semiconductor manufacturing is a list of conditions under which
7680-494: Is generally referred to as the " classic RISC pipeline ", which is quite common among the simple CPUs used in many electronic devices (often called microcontrollers). It largely ignores the important role of CPU cache, and therefore the access stage of the pipeline. Some instructions manipulate the program counter rather than producing result data directly; such instructions are generally called "jumps" and facilitate program behavior like loops , conditional program execution (through
7872-483: Is greater or whether they are equal; one of these flags could then be used by a later jump instruction to determine program flow. Fetch involves retrieving an instruction (which is represented by a number or sequence of numbers) from program memory. The instruction's location (address) in program memory is determined by the program counter (PC; called the "instruction pointer" in Intel x86 microprocessors ), which stores
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8064-400: Is largely addressed in modern processors by caches and pipeline architectures (see below). The instruction that the CPU fetches from memory determines what the CPU will do. In the decode step, performed by binary decoder circuitry known as the instruction decoder , the instruction is converted into signals that control other parts of the CPU. The way in which the instruction is interpreted
8256-530: Is most often credited with the design of the stored-program computer because of his design of EDVAC, and the design became known as the von Neumann architecture , others before him, such as Konrad Zuse , had suggested and implemented similar ideas. The so-called Harvard architecture of the Harvard Mark I , which was completed before EDVAC, also used a stored-program design using punched paper tape rather than electronic memory. The key difference between
8448-407: Is often based on tungsten and has upper and lower layers: the lower layer connects the junctions of the transistors, and an upper layer which is a tungsten plug that connects the transistors to the interconnect. Intel at the 10nm node introduced contact-over-active-gate (COAG) which, instead of placing the contact for connecting the transistor close to the gate of the transistor, places it directly over
8640-737: Is the IBM PowerPC -based Xenon used in the Xbox 360 ; this reduces the power requirements of the Xbox 360. Another method of addressing some of the problems with a global clock signal is the removal of the clock signal altogether. While removing the global clock signal makes the design process considerably more complex in many ways, asynchronous (or clockless) designs carry marked advantages in power consumption and heat dissipation in comparison with similar synchronous designs. While somewhat uncommon, entire asynchronous CPUs have been built without using
8832-472: Is the amount of working devices on a wafer. This mini environment is within an EFEM (equipment front end module) which allows a machine to receive FOUPs, and introduces wafers from the FOUPs into the machine. Additionally many machines also handle wafers in clean nitrogen or vacuum environments to reduce contamination and improve process control. Fabrication plants need large amounts of liquid nitrogen to maintain
9024-422: Is the process used to manufacture semiconductor devices , typically integrated circuits (ICs) such as computer processors , microcontrollers , and memory chips (such as RAM and Flash memory ). It is a multiple-step photolithographic and physico-chemical process (with steps such as thermal oxidation , thin-film deposition, ion-implantation, etching) during which electronic circuits are gradually created on
9216-637: The 845 chipset that supported much cheaper PC133 SDRAM instead of RDRAM. The fact that SDRAM was so much cheaper caused the Pentium 4's sales to grow considerably. The new chipset allowed the Pentium 4 to quickly replace the Pentium III, becoming the top-selling mainstream processor on the market. The Willamette code name is derived from the Willamette Valley region of Oregon, where a large number of Intel 's manufacturing facilities are located. In January 2002, Intel released Pentium 4s with
9408-676: The Allendale (and later Conroe ) desktop processors and in late 2007 with the Merom mobile processors, with the underlying microarchitecture being the Core microarchitecture . Central processing unit The form, design , and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic and logic operations , processor registers that supply operands to
9600-586: The Czochralski process . These ingots are then sliced into wafers about 0.75 mm thick and polished to obtain a very regular and flat surface. During the production process wafers are often grouped into lots, which are represented by a FOUP, SMIF or a wafer cassette, which are wafer carriers. FOUPs and SMIFs can be transported in the fab between machines and equipment with an automated OHT (Overhead Hoist Transport) AMHS (Automated Material Handling System). Besides SMIFs and FOUPs, wafer cassettes can be placed in
9792-514: The High-κ dielectric , creating dummy gates, manufacturing sources and drains by ion deposition and dopant annealing, depositing an "interlevel dielectric (ILD)" and then polishing, and removing the dummy gates to replace them with a metal whose workfunction depended on whether the transistor was NMOS or PMOS, thus creating the metal gate. A third process, full silicidation (FUSI) was not pursued due to manufacturing problems. Gate-first became dominant at
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#17327728099099984-488: The IBM z13 has a 96 KiB L1 instruction cache. Most CPUs are synchronous circuits , which means they employ a clock signal to pace their sequential operations. The clock signal is produced by an external oscillator circuit that generates a consistent number of pulses each second in the form of a periodic square wave . The frequency of the clock pulses determines the rate at which a CPU executes instructions and, consequently,
10176-674: The Journal of Applied Physics . In 1965, C.W. Mueller and P.H. Robinson fabricated a MOSFET (metal–oxide–semiconductor field-effect transistor) using the silicon-on-sapphire process at RCA Laboratories . Semiconductor device manufacturing has since spread from Texas and California in the 1960s to the rest of the world, including Asia , Europe , and the Middle East . Wafer size has grown over time, from 25 mm in 1960, to 50 mm in 1969, 100 mm in 1976, 125 mm in 1981, 150 mm in 1983 and 200 mm in 1992. In
10368-484: The P6 and NetBurst microarchitectures, Intel could not market Willamette as a Pentium III, so it was marketed as the Pentium 4. On November 20, 2000, Intel released the Willamette-based Pentium 4 clocked at 1.4 and 1.5 GHz. Most industry experts regarded the initial release as a stopgap product, introduced before it was truly ready. According to these experts, the Pentium 4 was released because
10560-474: The main memory . A cache is a smaller, faster memory, closer to a processor core , which stores copies of the data from frequently used main memory locations . Most CPUs have different independent caches, including instruction and data caches , where the data cache is usually organized as a hierarchy of more cache levels (L1, L2, L3, L4, etc.). All modern (fast) CPUs (with few specialized exceptions ) have multiple levels of CPU caches. The first CPUs that used
10752-505: The planar process in 1959 while at Fairchild Semiconductor . In 1948, Bardeen patented an insulated-gate transistor (IGFET) with an inversion layer, Bardeen's concept, forms the basis of CMOS technology today. An improved type of MOSFET technology, CMOS , was developed by Chih-Tang Sah and Frank Wanlass at Fairchild Semiconductor in 1963. CMOS was commercialised by RCA in the late 1960s. RCA commercially used CMOS for its 4000-series integrated circuits in 1968, starting with
10944-429: The transistors directly in the silicon . The raw wafer is engineered by the growth of an ultrapure, virtually defect-free silicon layer through epitaxy . In the most advanced logic devices , prior to the silicon epitaxy step, tricks are performed to improve the performance of the transistors to be built. One method involves introducing a straining step wherein a silicon variant such as silicon-germanium (SiGe)
11136-470: The " megahertz myth " campaign. AMD product marketing used a " PR-rating " system, which assigned a merit value based on relative performance to a baseline machine. At the launch of the Pentium 4, Intel stated that NetBurst-based processors were expected to scale to 10 GHz after several fabrication process generations. However, the clock speed of processors using the NetBurst microarchitecture reached
11328-466: The "Expensive Edition" and "Extremely Expensive". The added cache generally resulted in a noticeable performance increase in most processor intensive applications. Multimedia encoding and certain games benefited the most, with the Extreme Edition outperforming the Pentium 4, and even the two Athlon 64 variants, although the lower price and more balanced performance of the Athlon 64 (particularly
11520-437: The 1970s. High-k dielectric such as hafnium oxide (HfO 2 ) replaced silicon oxynitride (SiON), in order to prevent large amounts of leakage current in the transistor while allowing for continued scaling or shrinking of the transistors. However HfO 2 is not compatible with polysilicon gates which requires the use of a metal gate. Two approaches were used in production: gate-first and gate-last. Gate-first consists of depositing
11712-582: The 2.26 GHz, 2.4 GHz, and 2.53 GHz models in May, 2.66 GHz and 2.8 GHz models in August, and 3.06 GHz model in November. With Northwood, the Pentium 4 came of age. The battle for performance leadership remained competitive (as AMD introduced faster versions of the Athlon XP) but most observers agreed that the fastest-clocked Northwood-based Pentium 4 was usually ahead of its rival. This
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#173277280990911904-414: The 22nm node, because planar transistors which only have one surface acting as a channel, started to suffer from short channel effects. A startup called SuVolta created a technology called Deeply Depleted Channel (DDC) to compete with FinFET transistors, which uses planar transistors at the 65 nm node which are very lightly doped. By 2018, a number of transistor architectures had been proposed for
12096-601: The 22nm/20nm node. HKMG has been extended from planar transistors for use in FinFET and nanosheet transistors. Hafnium silicon oxynitride can also be used instead of Hafnium oxide. Since the 16nm/14nm node, Atomic layer etching (ALE) is increasingly used for etching as it offers higher precision than other etching methods. In production, plasma ALE is commonly used, which removes materials unidirectionally, creating structures with vertical walls. Thermal ALE can also be used to remove materials isotropically, in all directions at
12288-463: The 350nm and 250nm nodes (0.35 and 0.25 micron nodes), at the same time chemical mechanical polishing began to be employed. At the time, 2 metal layers for interconnect, also called metallization was state-of-the-art. Since the 22nm node, some manufacturers have added a new process called middle-of-line (MOL) which connects the transistors to the rest of the interconnect made in the BEoL process. The MOL
12480-558: The 5xx series (Celeron Ds are the 3xx series, while Pentium Ms are the 7xx series). The LGA 775 version of the E-series uses model numbers 5x0 (520–560), and the LGA 775 version of the A-series uses model numbers 5x5 and 5x9 (505–519). The fastest, the 570J and 571, is clocked at 3.8 GHz. Plans to mass-produce a 4 GHz Pentium 4 were cancelled by Intel in favor of dual core processors, although some European retailers claimed to be selling
12672-543: The 64-bit capable F-series to OEMs only. However, they were later made available to the general public as the 5x1 series. A number of low-end Intel 64-enabled Prescotts, with 533 MHz FSB speed, were also released. The E0 stepping of the Prescott series introduced the XD bit feature. This technology, introduced to the x86 architecture by AMD as NX (No eXecute) , can help prevent certain types of malicious code from exploiting
12864-446: The 90 nm and 65 nm parts respectively. The original successor to the Pentium 4 was (codenamed) Tejas , which was scheduled for an early-mid-2005 release. However, it was cancelled a few months after the release of Prescott due to extremely high TDPs (a 2.8 GHz Tejas emitted 150 W of heat, compared to around 80 W for a Northwood of the same speed, and 100 W for a comparably clocked Prescott) and development on
13056-537: The 90nm node, transistor channels made with strain engineering were introduced to improve drive current in PMOS transistors by introducing regions with Silicon-Germanium in the transistor. The same was done in NMOS transistors at the 20nm node. In 2007, HKMG (high-k/metal gate) transistors were introduced by Intel at the 45nm node, which replaced polysilicon gates which in turn replaced metal gate (aluminum gate) technology in
13248-453: The AGU, various address-generation calculations can be offloaded from the rest of the CPU, and can often be executed quickly in a single CPU cycle. Capabilities of an AGU depend on a particular CPU and its architecture . Thus, some AGUs implement and expose more address-calculation operations, while some also include more advanced specialized instructions that can operate on multiple operands at
13440-546: The ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory) , decoding and execution (of instructions) by directing the coordinated operations of the ALU, registers, and other components. Modern CPUs devote a lot of semiconductor area to caches and instruction-level parallelism to increase performance and to CPU modes to support operating systems and virtualization . Most modern CPUs are implemented on integrated circuit (IC) microprocessors , with one or more CPUs on
13632-431: The ALU's output word size), an arithmetic overflow flag will be set, influencing the next operation. Hardwired into a CPU's circuitry is a set of basic operations it can perform, called an instruction set . Such operations may involve, for example, adding or subtracting two numbers, comparing two numbers, or jumping to a different part of a program. Each instruction is represented by a unique combination of bits , known as
13824-616: The Athlon XP architecture was less dependent on bandwidth, the bandwidth numbers reached by Intel were well out of range for the Athlon's EV6 bus. Hypothetically, EV6 could have achieved the same bandwidth numbers, but only at speeds unreachable at the time. Intel's higher bandwidth proved useful in benchmarks for streaming operations, and Intel marketing wisely capitalized on this as a tangible improvement over AMD's desktop processors. Northwood 2.4 GHz, 2.6 GHz and 2.8 GHz variants were released on May 21, 2003. A 3.2 GHz variant
14016-468: The CPU can fetch the data from actual memory locations. Those address-generation calculations involve different integer arithmetic operations , such as addition, subtraction, modulo operations , or bit shifts . Often, calculating a memory address involves more than one general-purpose machine instruction, which do not necessarily decode and execute quickly. By incorporating an AGU into a CPU design, together with introducing specialized instructions that use
14208-479: The CPU to access main memory . By having address calculations handled by separate circuitry that operates in parallel with the rest of the CPU, the number of CPU cycles required for executing various machine instructions can be reduced, bringing performance improvements. While performing various operations, CPUs need to calculate memory addresses required for fetching data from the memory; for example, in-memory positions of array elements must be calculated before
14400-422: The CPU to malfunction. Another major issue, as clock rates increase dramatically, is the amount of heat that is dissipated by the CPU . The constantly changing clock causes many components to switch regardless of whether they are being used at that time. In general, a component that is switching uses more energy than an element in a static state. Therefore, as clock rate increases, so does energy consumption, causing
14592-467: The CPU to require more heat dissipation in the form of CPU cooling solutions. One method of dealing with the switching of unneeded components is called clock gating , which involves turning off the clock signal to unneeded components (effectively disabling them). However, this is often regarded as difficult to implement and therefore does not see common usage outside of very low-power designs. One notable recent CPU design that uses extensive clock gating
14784-411: The CPU was released using the new Socket 775 ( LGA 775 ). A slight performance increase was achieved in late 2004 by increasing the bus speed from 800 MT/s to 1066 MT/s, resulting in a 3.46 GHz Pentium 4 Extreme Edition. By most metrics, this was on a per-clock basis the fastest single-core NetBurst processor that was ever produced, even outperforming many of its successor chips (not counting
14976-523: The IHS, a CPU shim was some times used by people worried about damaging the core. Overclockers sometimes removed the IHS from Socket 423 and Socket 478 chips to allow for more direct heat transfer. On Socket 478 Prescott processors and processors using the Socket LGA 775 (Socket T) interface, the IHS is directly soldered to the die or dies, making it difficult to remove. Willamette, the project codename for
15168-812: The NetBurst microarchitecture as a whole ceased, with the exception of the dual-core Pentium D, Pentium Extreme Edition and the Cedar Mill-based Pentium 4 HT. The real successor to the Pentium 4 brand is the Pentium Dual-Core brand, released in 2006. The first chips implementing it (in 65 nm) were released in January 2007 with the Yonah mobile processors and are based on the Enhanced Pentium M architecture, in June 3, 2007 with
15360-524: The Pentium 4 M, the mobile version of the Pentium 4, was discontinued after suffering from heat and power consumption problems and was replaced by the Pentium M . The Pentium M was part of the Intel Centrino platform-marketing brand. In May 2005, Intel released dual-core processors under the Pentium D and Pentium Extreme Edition brands. These came under the code names Smithfield and Presler for
15552-461: The Pentium 4 processor is significantly more complex than any previous IA-32 microprocessor, so the challenge of validating the logical correctness of the design in a timely fashion was indeed a daunting one." He hired a team of 60 recent graduates to help with testing and validation. Pentium 4 processors have an integrated heat spreader (IHS) that prevents the die from accidentally being damaged when mounting and unmounting cooling solutions. Prior to
15744-485: The Pentium 4 was Cedar Mill , released on January 5, 2006. This was a die shrink of the Prescott-based 600 series core to 65 nm , with no real feature additions but significantly reduced power consumption. The Cedar Mill is closely linked to the Pentium D Presler revision, with each Presler CPU consisting of two Cedar Mill cores on the same chip package. Cedar Mill had a lower heat output than Prescott, with
15936-503: The Pentium 4 would merely match or run slower than its predecessor. Its main downfall was a shared unidirectional bus. The NetBurst microarchitecture consumed more power and emitted more heat than any previous Intel or AMD microarchitectures. As a result, the Pentium 4's introduction was met with mixed reviews: Developers disliked the Pentium 4, as it posed a new set of code optimization rules. For example, in mathematical applications, AMD's lower-clocked Athlon (the fastest-clocked model
16128-510: The Pentium 4's singular emphasis on clock frequency (above all else) made it a marketer's dream. The result of this was that the NetBurst microarchitecture was often referred to as a marchitecture by various computing websites and publications during the life of the Pentium 4. It was also called "NetBust", a term popular with reviewers who reflected negatively upon the processor's performance. The two classical metrics of CPU performance are instructions per cycle (IPC) and clock speed . While IPC
16320-497: The Precision 5000. Until the 1980s, physical vapor deposition was the primary technique used for depositing materials onto wafers, until the advent of chemical vapor deposition. Equipment with diffusion pumps was replaced with those using turbomolecular pumps as the latter do not use oil which often contaminated wafers during processing in vacuum. 200 mm diameter wafers were first used in 1990 for making chips. These became
16512-511: The Producer, a cluster tool that had chambers grouped in pairs for processing wafers, which shared common vacuum and supply lines but were otherwise isolated, which was revolutionary at the time as it offered higher productivity than other cluster tools without sacrificing quality, due to the isolated chamber design. The semiconductor industry is a global business today. The leading semiconductor manufacturers typically have facilities all over
16704-538: The Socket 775/LGA 775 versions of the Pentium 4 Extreme Edition, as well as the Pentium Extreme Edition (Smithfield) and Engineering Sample CPUs have unlocked multipliers. On February 1, 2004, Intel introduced a new core codenamed Prescott. The core used the 90 nm process for the first time, which one analyst described as "a major reworking of the Pentium 4's microarchitecture." Despite this overhaul,
16896-460: The XD ;bit, EIST (Enhanced Intel SpeedStep Technology), Thermal Monitor 2 (for processors at 3.6 GHz and above), and 2 MB of L2 cache. However, AnandTech found that this resulted in 17% higher cache latency compared to Prescott, which combined with the lack of consumer-targeted programs requiring more cache, largely negated the advantage that added cache introduced. Rather than being
17088-530: The adoption of FOUPs, but many products that are not advanced are still produced in 200 mm wafers such as analog ICs, RF chips, power ICs, BCDMOS and MEMS devices. Some processes such as cleaning, ion implantation, etching, annealing and oxidation started to adopt single wafer processing instead of batch wafer processing in order to improve the reproducibility of results. A similar trend existed in MEMS manufacturing. In 1998, Applied Materials introduced
17280-431: The advent and eventual success of the ubiquitous personal computer , the term CPU is now applied almost exclusively to microprocessors. Several CPUs (denoted cores ) can be combined in a single processing chip. Previous generations of CPUs were implemented as discrete components and numerous small integrated circuits (ICs) on one or more circuit boards. Microprocessors, on the other hand, are CPUs manufactured on
17472-454: The advent of the stored-program computer . The idea of a stored-program computer had been already present in the design of John Presper Eckert and John William Mauchly 's ENIAC , but was initially omitted so that it could be finished sooner. On June 30, 1945, before ENIAC was made, mathematician John von Neumann distributed a paper entitled First Draft of a Report on the EDVAC . It was
17664-428: The advent of the transistor . Transistorized CPUs during the 1950s and 1960s no longer had to be built out of bulky, unreliable, and fragile switching elements, like vacuum tubes and relays . With this improvement, more complex and reliable CPUs were built onto one or several printed circuit boards containing discrete (individual) components. In 1964, IBM introduced its IBM System/360 computer architecture that
17856-400: The air in the cleanroom; semiconductor capital equipment may also have their own FFUs to clean air in the equipment's EFEM which allows the equipment to receive wafers in FOUPs. The FFUs, combined with raised floors with grills, help ensure a laminar air flow, to ensure that particles are immediately brought down to the floor and do not stay suspended in the air due to turbulence. The workers in
18048-547: The atmosphere inside production machinery and FOUPs, which are constantly purged with nitrogen. There can also be an air curtain or a mesh between the FOUP and the EFEM which helps reduce the amount of humidity that enters the FOUP and improves yield. Companies that manufacture machines used in the industrial semiconductor fabrication process include ASML , Applied Materials , Tokyo Electron and Lam Research . Feature size
18240-544: The average utilization of semiconductor devices increased, durability became an issue and manufacturers started to design their devices to ensure they last for enough time, and this depends on the market the device is designed for. This especially became a problem at the 10 nm node. Silicon on insulator (SOI) technology has been used in AMD 's 130 nm, 90 nm, 65 nm, 45 nm and 32 nm single, dual, quad, six and eight core processors made since 2001. During
18432-512: The cache size, and using a longer instruction pipeline along with higher clock speeds. The code cache was replaced by a trace cache which contained decoded microoperations rather than instructions with advantage of eliminating instruction decoding bottleneck so that the design can use RISC technology. This came with a disadvantage of less compact cache taking up more chip space and consuming power. These solutions failed, and from 2003 to 2005, Intel shifted development away from NetBurst to focus on
18624-400: The carrier, processed and returned to the carrier, so acid-resistant carriers were developed to eliminate this time consuming process, so the entire cassette with wafers was dipped into wet etching and wet cleaning tanks. When wafer sizes increased to 100 mm, the entire cassette would often not be dipped as uniformly, and the quality of the results across the wafer became hard to control. By
18816-499: The chip. Normally a new semiconductor process has smaller minimum sizes and tighter spacing. In some cases, this allows a simple die shrink of a currently produced chip design to reduce costs, improve performance, and increase transistor density (number of transistors per unit area) without the expense of a new design. Early semiconductor processes had arbitrary names for generations (viz., HMOS I/II/III/IV and CHMOS III/III-E/IV/V). Later each new generation process became known as
19008-476: The company's financial abilities. From 2020 to 2022, there was a global chip shortage . During this shortage caused by the COVID-19 pandemic, many semiconductor manufacturers banned employees from leaving company grounds. Many countries granted subsidies to semiconductor companies for building new fabrication plants or fabs. Many companies were affected by counterfeit chips. Semiconductors have become vital to
19200-448: The competing Thunderbird-based AMD Athlon was outperforming the aging Pentium III, and further improvements to the Pentium III were not yet possible. This Pentium 4 was produced using a 180 nm process and initially used Socket 423 (also called socket W, for "Willamette"), with later revisions moving to Socket 478 (socket N, for "Northwood"). These variants were identified by the Intel product codes 80528 and 80531 respectively. On
19392-564: The complexity and number of transistors in a single CPU many fold. This widely observed trend is described by Moore's law , which had proven to be a fairly accurate predictor of the growth of CPU (and other IC) complexity until 2016. While the complexity, size, construction and general form of CPUs have changed enormously since 1950, the basic design and function has not changed much at all. Almost all common CPUs today can be very accurately described as von Neumann stored-program machines. As Moore's law no longer holds, concerns have arisen about
19584-423: The complexity scale, a machine language program is a collection of machine language instructions that the CPU executes. The actual mathematical operation for each instruction is performed by a combinational logic circuit within the CPU's processor known as the arithmetic–logic unit or ALU. In general, a CPU executes an instruction by fetching it from memory, using its ALU to perform an operation, and then storing
19776-486: The control unit as part of the von Neumann architecture . In modern computer designs, the control unit is typically an internal part of the CPU with its overall role and operation unchanged since its introduction. The arithmetic logic unit (ALU) is a digital circuit within the processor that performs integer arithmetic and bitwise logic operations. The inputs to the ALU are the data words to be operated on (called operands ), status information from previous operations, and
19968-519: The cooler-running Pentium M microarchitecture. On January 5, 2006, Intel launched the Core processors, which put greater emphasis on energy efficiency and performance per clock cycle. The final NetBurst-derived products were released in 2007, with all subsequent product families switching exclusively to the Core microarchitecture. According to Bob Bentley, presenting on behalf of Intel at the 38th annual Design Automation Conference, "The microarchitecture of
20160-502: The depth of focus of available lithography, and thus interfering with the ability to pattern. CMP ( chemical-mechanical planarization ) is the primary processing method to achieve such planarization, although dry etch back is still sometimes employed when the number of interconnect levels is no more than three. Copper interconnects use an electrically conductive barrier layer to prevent the copper from diffusing into ("poisoning") its surroundings, often made of tantalum nitride. In 1997, IBM
20352-424: The desired complementary electrical properties. In dynamic random-access memory (DRAM) devices, storage capacitors are also fabricated at this time, typically stacked above the access transistor (the now defunct DRAM manufacturer Qimonda implemented these capacitors with trenches etched deep into the silicon surface). Once the various semiconductor devices have been created , they must be interconnected to form
20544-746: The desired electrical circuits. This occurs in a series of wafer processing steps collectively referred to as BEOL (not to be confused with back end of chip fabrication, which refers to the packaging and testing stages). BEOL processing involves creating metal interconnecting wires that are isolated by dielectric layers. The insulating material has traditionally been a form of SiO 2 or a silicate glass , but recently new low dielectric constant materials, also called low-κ dielectrics, are being used (such as silicon oxycarbide), typically providing dielectric constants around 2.7 (compared to 3.82 for SiO 2 ), although materials with constants as low as 2.2 are being offered to chipmakers. BEoL has been used since 1995 at
20736-453: The desired operation. The action is then completed, typically in response to a clock pulse. Very often the results are written to an internal CPU register for quick access by subsequent instructions. In other cases results may be written to slower, but less expensive and higher capacity main memory . For example, if an instruction that performs addition is to be executed, registers containing operands (numbers to be summed) are activated, as are
20928-427: The desktop Pentium 4, the Pentium 4 M did not feature an integrated heat spreader (IHS), and it operates at a lower voltage. The lower voltage means lower power consumption, and in turn less heat. However, according to Intel specifications, the Pentium 4 M had a maximum thermal junction temperature rating of 100 degrees C, approximately 40 degrees higher than the desktop Pentium 4. The Mobile Intel Pentium 4 Processor
21120-429: The drawbacks of globally synchronous CPUs. For example, a clock signal is subject to the delays of any other electrical signal. Higher clock rates in increasingly complex CPUs make it more difficult to keep the clock signal in phase (synchronized) throughout the entire unit. This has led many modern CPUs to require multiple identical clock signals to be provided to avoid delaying a single signal significantly enough to cause
21312-546: The dual-core Pentium D ), the Core 2 Extreme , the Core i7 and the Core i9 . Contrary to popular belief, however, the Socket 478 versions of the Pentium 4 Extreme Edition CPUs such as the Gallatin-based Pentium 4 Extreme Edition for Socket 478 all have a locked multiplier, meaning that they are not overclockable unless the front-side bus speeds are increased (which runs the potential risks of erratic behaviors such as reliability and stability issues). Only
21504-401: The dual-core Pentium D). Afterwards, the Pentium 4 Extreme Edition was migrated to the Prescott core. The new 3.73 GHz Extreme Edition had the same features as a 6x0-sequence Prescott 2M, but with a 1066 MT/s bus. In practice however, the 3.73 GHz Pentium 4 Extreme Edition almost always proved to be slower than the 3.46 GHz Pentium 4 Extreme Edition, which is most likely due to
21696-453: The early 1980s). In the 1960s, MOS ICs were slower and initially considered useful only in applications that required low power. Following the development of silicon-gate MOS technology by Federico Faggin at Fairchild Semiconductor in 1968, MOS ICs largely replaced bipolar TTL as the standard chip technology in the early 1970s. As the microelectronic technology advanced, an increasing number of transistors were placed on ICs, decreasing
21888-411: The entire wafer is scrapped to avoid the costs of further processing. Virtual metrology has been used to predict wafer properties based on statistical methods without performing the physical measurement itself. Once the front-end process has been completed, the semiconductor devices or chips are subjected to a variety of electrical tests to determine if they function properly. The percent of devices on
22080-413: The era of 2 inch wafers, these were handled manually using tweezers and held manually for the time required for a given process. Tweezers were replaced by vacuum wands as they generate fewer particles which can contaminate the wafers. Wafer carriers or cassettes, which can hold several wafers at once, were developed to carry several wafers between process steps, but wafers had to be individually removed from
22272-578: The era of specialized supercomputers like those made by Cray Inc and Fujitsu Ltd . During this period, a method of manufacturing many interconnected transistors in a compact space was developed. The integrated circuit (IC) allowed a large number of transistors to be manufactured on a single semiconductor -based die , or "chip". At first, only very basic non-specialized digital circuits such as NOR gates were miniaturized into ICs. CPUs based on these "building block" ICs are generally referred to as "small-scale integration" (SSI) devices. SSI ICs, such as
22464-605: The eventual replacement of FinFET , most of which were based on the concept of GAAFET : horizontal and vertical nanowires, horizontal nanosheet transistors (Samsung MBCFET, Intel Nanoribbon), vertical FET (VFET) and other vertical transistors, complementary FET (CFET), stacked FET, vertical TFETs, FinFETs with III-V semiconductor materials (III-V FinFET), several kinds of horizontal gate-all-around transistors such as nano-ring, hexagonal wire, square wire, and round wire gate-all-around transistors and negative-capacitance FET (NC-FET) which uses drastically different materials. FD-SOI
22656-503: The execution of an instruction, the entire process repeats, with the next instruction cycle normally fetching the next-in-sequence instruction because of the incremented value in the program counter . If a jump instruction was executed, the program counter will be modified to contain the address of the instruction that was jumped to and program execution continues normally. In more complex CPUs, multiple instructions can be fetched, decoded and executed simultaneously. This section describes what
22848-508: The extra 1 added to the model number distinguishing them from the 90 nm Prescott cores operating at the same frequencies. Cedar Mill processors ranged in frequency from 3.0 to 3.6 GHz, down from the 3.8 GHz maximum of the Prescott-based 670 and 672. Overclockers managed to exceed 8 GHz with these processors using liquid nitrogen cooling. The name "Cedar Mill" refers to Cedar Mill, Oregon , an unincorporated community near Intel's Hillsboro, Oregon facilities. In March 2003,
23040-401: The faster the clock, the more instructions the CPU will execute each second. To ensure proper operation of the CPU, the clock period is longer than the maximum time needed for all signals to propagate (move) through the CPU. In setting the clock period to a value well above the worst-case propagation delay , it is possible to design the entire CPU and the way it moves data around the "edges" of
23232-601: The first NetBurst microarchitecture implementation, experienced long delays in the completion of its design process. The project was started in 1998, when Intel saw the Pentium II as their permanent line. At that time, the Willamette core was expected to operate at frequencies up to about 1 GHz. However, the Pentium III was released while Willamette was still being finished. Due to the radical differences between
23424-437: The first automatic reticle and photomask inspection tool. In 1985, KLA developed an automatic inspection tool for silicon wafers, which replaced manual microscope inspection. In 1985, SGS (now STmicroelectronics ) invented BCD, also called BCDMOS , a semiconductor manufacturing process using bipolar , CMOS and DMOS devices. Applied Materials developed the first practical multi chamber, or cluster wafer processing tool,
23616-525: The first planar field effect transistors, in which drain and source were adjacent at the same surface. At Bell Labs, the importance of their discoveries was immediately realized. Memos describing the results of their work circulated around Bell Labs before being formally published in 1957. At Shockley Semiconductor , Shockley had circulated the preprint of their article in December 1956 to all his senior staff, including Jean Hoerni , who would later invent
23808-438: The gate of the transistor to improve transistor density. Historically, the metal wires have been composed of aluminum . In this approach to wiring (often called subtractive aluminum ), blanket films of aluminum are deposited first, patterned, and then etched, leaving isolated wires. Dielectric material is then deposited over the exposed wires. The various metal layers are interconnected by etching holes (called " vias") in
24000-403: The high-k dielectric and then the gate metal such as Tantalum nitride whose workfunction depends on whether the transistor is NMOS or PMOS, polysilicon deposition, gate line patterning, source and drain ion implantation, dopant anneal, and silicidation of the polysilicon and the source and drain. In DRAM memories this technology was first adopted in 2015. Gate-last consisted of first depositing
24192-559: The individual transistors used by the PDP-8 and PDP-10 to SSI ICs, and their extremely popular PDP-11 line was originally built with SSI ICs, but was eventually implemented with LSI components once these became practical. Lee Boysel published influential articles, including a 1967 "manifesto", which described how to build the equivalent of a 32-bit mainframe computer from a relatively small number of large-scale integration circuits (LSI). The only way to build LSI chips, which are chips with
24384-523: The industry average. Production in advanced fabrication facilities is completely automated, with automated material handling systems taking care of the transport of wafers from machine to machine. A wafer often has several integrated circuits which are called dies as they are pieces diced from a single wafer. Individual dies are separated from a finished wafer in a process called die singulation , also called wafer dicing. The dies can then undergo further assembly and packaging. Within fabrication plants,
24576-412: The insulating material and then depositing tungsten in them with a CVD technique using tungsten hexafluoride ; this approach can still be (and often is) used in the fabrication of many memory chips such as dynamic random-access memory (DRAM), because the number of interconnect levels can be small (no more than four). The aluminum was sometimes alloyed with copper for preventing recrystallization. Gold
24768-423: The interconnect (from silicon dioxides to newer low-κ insulators). This performance enhancement also comes at a reduced cost via damascene processing, which eliminates processing steps. As the number of interconnect levels increases, planarization of the previous layers is required to ensure a flat surface prior to subsequent lithography. Without it, the levels would become increasingly crooked, extending outside
24960-405: The lack of an L3 cache and the longer instruction pipeline. The only advantage the 3.73 GHz Pentium 4 Extreme Edition had over the 3.46 GHz Pentium 4 Extreme Edition was the ability to run 64-bit applications since all Gallatin-based Pentium 4 Extreme Edition processors lacked the Intel 64 (then known as EM64T) instruction set. Although never a particularly good seller, especially since it
25152-481: The launch of the Athlon XP 3200+ in AMD's desktop line, AMD increased the Athlon XP's FSB speed from 333 MT/s to 400 MT/s, but it was not enough to hold off the new 3 GHz Pentium 4 HT. The Pentium 4 HT's increase to a 200 MHz quad-pumped bus (200 x 4 = 800 MHz effective) greatly helped to satisfy the bandwidth requirements the NetBurst architecture desired for reaching optimal performance. While
25344-439: The limits of integrated circuit transistor technology. Extreme miniaturization of electronic gates is causing the effects of phenomena like electromigration and subthreshold leakage to become much more significant. These newer concerns are among the many factors causing researchers to investigate new methods of computing such as the quantum computer , as well as to expand the use of parallelism and other methods that extend
25536-408: The location of a value that may be a processor register or a memory address, as determined by some addressing mode . In some CPU designs, the instruction decoder is implemented as a hardwired, unchangeable binary decoder circuit. In others, a microprogram is used to translate instructions into sets of CPU configuration signals that are applied sequentially over multiple clock pulses. In some cases
25728-406: The machine language opcode . While processing an instruction, the CPU decodes the opcode (via a binary decoder ) into control signals, which orchestrate the behavior of the CPU. A complete machine language instruction consists of an opcode and, in many cases, additional bits that specify arguments for the operation (for example, the numbers to be summed in the case of an addition operation). Going up
25920-421: The memory that stores the microprogram is rewritable, making it possible to change the way in which the CPU decodes instructions. After the fetch and decode steps, the execute step is performed. Depending on the CPU architecture, this may consist of a single action or a sequence of actions. During each action, control signals electrically enable or disable various parts of the CPU so they can perform all or part of
26112-470: The mobile Pentium 4 to bridge the gap between the desktop Pentium 4 (up to 115 W TDP), and the Pentium 4 M (up to 35 W TDP). Intel's naming conventions made it difficult at the time of the processor's release to identify the processor model. There was the Pentium III mobile chip, the Pentium 4 M, the Mobile Pentium 4, and then the Pentium M , which itself was based on the Pentium III and
26304-530: The name of its 10 nm process to position it as a 7 nm process. As transistors become smaller, new effects start to influence design decisions such as self-heating of the transistors, and other effects such as electromigration have become more evident since the 16nm node. In 2011, Intel demonstrated Fin field-effect transistors (FinFETs), where the gate surrounds the channel on three sides, allowing for increased energy efficiency and lower gate delay—and thus greater performance—over planar transistors at
26496-429: The night of 16–17 June 1949. Early CPUs were custom designs used as part of a larger and sometimes distinctive computer. However, this method of designing custom CPUs for a particular application has largely given way to the development of multi-purpose processors produced in large quantities. This standardization began in the era of discrete transistor mainframes and minicomputers , and has rapidly accelerated with
26688-443: The node with the highest transistor density is TSMC's 5 nanometer N5 node, with a density of 171.3 million transistors per square millimeter. In 2019, Samsung and TSMC announced plans to produce 3 nanometer nodes. GlobalFoundries has decided to stop the development of new nodes beyond 12 nanometers in order to save resources, as it has determined that setting up a new fab to handle sub-12 nm orders would be beyond
26880-453: The non-FX version) led to it usually being seen as the better value proposition. Nonetheless, the Extreme Edition did achieve Intel's apparent aim, which was to prevent AMD from being the performance champion with the new Athlon 64, which was winning every single major benchmark over the existing Pentium 4s. In January 2004, a 3.4 GHz version was released for Socket 478, and in Summer 2004
27072-474: The number of defects caused by dust particles. Also, fabs have as few people as possible in the cleanroom to make maintaining the cleanroom environment easier, since people, even when wearing cleanroom suits, shed large amounts of particles, especially when walking. A typical wafer is made out of extremely pure silicon that is grown into mono-crystalline cylindrical ingots ( boules ) up to 300 mm (slightly less than 12 inches) in diameter using
27264-710: The number of individual ICs needed for a complete CPU. MSI and LSI ICs increased transistor counts to hundreds, and then thousands. By 1968, the number of ICs required to build a complete CPU had been reduced to 24 ICs of eight different types, with each IC containing roughly 1000 MOSFETs. In stark contrast with its SSI and MSI predecessors, the first LSI implementation of the PDP-11 contained a CPU composed of only four LSI integrated circuits. Since microprocessors were first introduced they have almost completely overtaken all other central processing unit implementation methods. The first commercially available microprocessor, made in 1971,
27456-583: The ones used in the Apollo Guidance Computer , usually contained up to a few dozen transistors. To build an entire CPU out of SSI ICs required thousands of individual chips, but still consumed much less space and power than earlier discrete transistor designs. IBM's System/370 , follow-on to the System/360, used SSI ICs rather than Solid Logic Technology discrete-transistor modules. DEC's PDP-8 /I and KI10 PDP-10 also switched from
27648-400: The outline of a stored-program computer that would eventually be completed in August 1949. EDVAC was designed to perform a certain number of instructions (or operations) of various types. Significantly, the programs written for EDVAC were to be stored in high-speed computer memory rather than specified by the physical wiring of the computer. This overcame a severe limitation of ENIAC, which
27840-409: The parts of the arithmetic logic unit (ALU) that perform addition. When the clock pulse occurs, the operands flow from the source registers into the ALU, and the sum appears at its output. On subsequent clock pulses, other components are enabled (and disabled) to move the output (the sum of the operation) to storage (e.g., a register or memory). If the resulting sum is too large (i.e., it is larger than
28032-543: The performance gains were inconsistent. Some programs benefited from Prescott's doubled cache and SSE3 instructions, whereas others were harmed by its longer pipeline. The Prescott's microarchitecture allowed slightly higher clock speeds, but not nearly as high as Intel had anticipated. The fastest mass-produced Prescott-based Pentium 4s were clocked at 3.8 GHz. While Northwood ultimately achieved clock speeds 70% higher than Willamette, Prescott only scaled 12% beyond Northwood. Prescott's inability to achieve greater clock speeds
28224-501: The popularization of the integrated circuit (IC). The IC has allowed increasingly complex CPUs to be designed and manufactured to tolerances on the order of nanometers . Both the miniaturization and standardization of CPUs have increased the presence of digital devices in modern life far beyond the limited application of dedicated computing machines. Modern microprocessors appear in electronic devices ranging from automobiles to cellphones, and sometimes even in toys. While von Neumann
28416-473: The possible exception of the last level. Each extra level of cache tends to be bigger and is optimized differently. Other types of caches exist (that are not counted towards the "cache size" of the most important caches mentioned above), such as the translation lookaside buffer (TLB) that is part of the memory management unit (MMU) that most CPUs have. Caches are generally sized in powers of two: 2, 8, 16 etc. KiB or MiB (for larger non-L1) sizes, although
28608-451: The processor. It tells the computer's memory, arithmetic and logic unit and input and output devices how to respond to the instructions that have been sent to the processor. It directs the operation of the other units by providing timing and control signals. Most computer resources are managed by the CU. It directs the flow of data between the CPU and the other devices. John von Neumann included
28800-478: The reliability problems. Most of these early synchronous CPUs ran at low clock rates compared to modern microelectronic designs. Clock signal frequencies ranging from 100 kHz to 4 MHz were very common at this time, limited largely by the speed of the switching devices they were built with. The design complexity of CPUs increased as various technologies facilitated the building of smaller and more reliable electronic devices. The first such improvement came with
28992-409: The result to memory. Besides the instructions for integer mathematics and logic operations, various other machine instructions exist, such as those for loading data from memory and storing it back, branching operations, and mathematical operations on floating-point numbers performed by the CPU's floating-point unit (FPU). The control unit (CU) is a component of the CPU that directs the operation of
29184-484: The rising and falling clock signal. This has the advantage of simplifying the CPU significantly, both from a design perspective and a component-count perspective. However, it also carries the disadvantage that the entire CPU must wait on its slowest elements, even though some portions of it are much faster. This limitation has largely been compensated for by various methods of increasing CPU parallelism (see below). However, architectural improvements alone do not solve all of
29376-532: The same Gallatin core as the Xeon MP, though in a Socket 478 form factor (as opposed to Socket 603 for the Xeon MP) and with an 800 MT/s bus, twice as fast as that of the Xeon MP. While Intel maintained that the Extreme Edition was aimed at gamers, critics viewed it as an attempt to steal the Athlon 64's launch thunder, nicknaming it the "Emergency Edition". With a price tag of $ 1000, it was also referred to as
29568-411: The same month boards utilizing the 845 chipset were released with enabled support for DDR SDRAM which provided double the bandwidth of PC133 SDRAM, and alleviated the associated high costs of using Rambus RDRAM for maximal performance with Pentium 4. A 2.4 GHz Pentium 4 was released on April 2, 2002, and the bus speed increased from 400 MT/s to 533 MT/s (133 MHz physical clock) for
29760-469: The same time but without the capability to create vertical walls. Plasma ALE was initially adopted for etching contacts in transistors, and since the 7nm node it is also used to create transistor structures by etching them. Front-end surface engineering is followed by growth of the gate dielectric (traditionally silicon dioxide ), patterning of the gate, patterning of the source and drain regions, and subsequent implantation or diffusion of dopants to obtain
29952-461: The same time on the same physical processor. By shuffling two (ideally differing) program instructions to simultaneously execute through a single physical processor core, the goal is to best utilize processor resources that would have otherwise been unused from the traditional approach of having these single instructions wait for each other to execute singularly through the core. This initial 3.06 GHz 533FSB Pentium 4 Hyper-Threading enabled processor
30144-540: The short switching time of a transistor in comparison to a tube or relay. The increased reliability and dramatically increased speed of the switching elements, which were almost exclusively transistors by this time; CPU clock rates in the tens of megahertz were easily obtained during this period. Additionally, while discrete transistor and IC CPUs were in heavy usage, new high-performance designs like single instruction, multiple data (SIMD) vector processors began to appear. These early experimental designs later gave rise to
30336-566: The sole purpose of managing the Prescott's heat output at the expense of other components and concerns, such as blowing hot air from the CPU directly into the graphics card's heatsink/fan. These magnified the perception of Prescott as an excessively hot chip. The Prescott Pentium 4 contains 125 million transistors and has a die area of 112 mm. It was fabricated in a 90 nm process with seven levels of copper interconnect . The process has features such as strained silicon transistors and low-κ carbon-doped silicon oxide (CDO) dielectric, which
30528-455: The standard until the introduction of 300 mm diameter wafers in 2000. Bridge tools were used in the transition from 150 mm wafers to 200 mm wafers and in the transition from 200 mm to 300 mm wafers. The semiconductor industry has adopted larger wafers to cope with the increased demand for chips as larger wafers provide more surface area per wafer. Over time, the industry shifted to 300 mm wafers which brought along
30720-446: The test bench, the Willamette was somewhat disappointing to analysts in that not only was it unable to outperform the Athlon and the highest-clocked Pentium IIIs in all testing situations, but it was not superior to the budget segment's AMD Duron . Although introduced at prices of $ 644 (1.4 GHz) and $ 819 (1.5 GHz) for 1000 quantities to OEM PC manufacturers (prices for models for the consumer market varied by retailer), it sold at
30912-505: The time 150 mm wafers arrived, the cassettes were not dipped and were only used as wafer carriers and holders to store wafers, and robotics became prevalent for handling wafers. With 200 mm wafers manual handling of wafer cassettes becomes risky as they are heavier. In the 1970s, several companies migrated their semiconductor manufacturing technology from bipolar to CMOS technology. Semiconductor manufacturing equipment has been considered costly since 1978. In 1984, KLA developed
31104-461: The top range by the Core 2 brand, while production continued until 2008, with Pentium 4 replaced by Pentium Dual-Core . In benchmark evaluations, the advantages of the NetBurst microarchitecture were unclear. With carefully optimized application code, the first Pentium 4s outperformed Intel's fastest Pentium III (clocked at 1.13 GHz at the time), as expected. But in legacy applications with many branching or x87 floating-point instructions,
31296-611: The transition from 200 mm to 300 mm wafers in 2001, many bridge tools were used which could process both 200 mm and 300 mm wafers. At the time, 18 companies could manufacture chips in the leading edge 130nm process. In 2006, 450 mm wafers were expected to be adopted in 2012, and 675 mm wafers were expected to be used by 2021. Since 2009, "node" has become a commercial name for marketing purposes that indicates new generations of process technologies, without any relation to gate length, metal pitch or gate pitch. For example, GlobalFoundries ' 7 nm process
31488-504: The two types of transistors separately and then stacked them. This is a list of processing techniques that are employed numerous times throughout the construction of a modern electronic device; this list does not necessarily imply a specific order, nor that all techniques are taken during manufacture as, in practice the order and which techniques are applied, are often specific to process offerings by foundries, or specific to an integrated device manufacturer (IDM) for their own products, and
31680-422: The use of a conditional jump), and existence of functions . In some processors, some other instructions change the state of bits in a "flags" register . These flags can be used to influence how a program behaves, since they often indicate the outcome of various operations. For example, in such processors a "compare" instruction evaluates two values and sets or clears bits in the flags register to indicate which one
31872-431: The usefulness of the classical von Neumann model. The fundamental operation of most CPUs, regardless of the physical form they take, is to execute a sequence of stored instructions that is called a program. The instructions to be executed are kept in some kind of computer memory . Nearly all CPUs follow the fetch, decode and execute steps in their operation, which are collectively known as the instruction cycle . After
32064-478: The various processing steps. For example, thin film metrology based on ellipsometry or reflectometry is used to tightly control the thickness of gate oxide, as well as the thickness, refractive index, and extinction coefficient of photoresist and other coatings. Wafer metrology equipment/tools, or wafer inspection tools are used to verify that the wafers haven't been damaged by previous processing steps up until testing; if too many dies on one wafer have failed,
32256-616: The von Neumann and Harvard architectures is that the latter separates the storage and treatment of CPU instructions and data, while the former uses the same memory space for both. Most modern CPUs are primarily von Neumann in design, but CPUs with the Harvard architecture are seen as well, especially in embedded applications; for instance, the Atmel AVR microcontrollers are Harvard-architecture processors. Relays and vacuum tubes (thermionic tubes) were commonly used as switching elements;
32448-445: The wafers are transported inside special sealed plastic boxes called FOUPs . FOUPs in many fabs contain an internal nitrogen atmosphere which helps prevent copper from oxidizing on the wafers. Copper is used in modern semiconductors for wiring. The insides of the processing equipment and FOUPs is kept cleaner than the surrounding air in the cleanroom. This internal atmosphere is known as a mini-environment and helps improve yield which
32640-422: The world economy and the national security of some countries. The US has asked TSMC to not produce semiconductors for Huawei, a Chinese company. CFET transistors were explored, which stacks NMOS and PMOS transistors on top of each other. Two approaches were evaluated for constructing these transistors: a monolithic approach which built both types of transistors in one process, and a sequential approach which built
32832-738: The world. Samsung Electronics , the world's largest manufacturer of semiconductors, has facilities in South Korea and the US. Intel , the second-largest manufacturer, has facilities in Europe and Asia as well as the US. TSMC , the world's largest pure play foundry , has facilities in Taiwan, China, Singapore, and the US. Qualcomm and Broadcom are among the biggest fabless semiconductor companies, outsourcing their production to companies like TSMC. They also have facilities spread in different countries. As
33024-429: Was also used in interconnects in early chips. More recently, as the number of interconnect levels for logic has substantially increased due to the large number of transistors that are now interconnected in a modern microprocessor , the timing delay in the wiring has become so significant as to prompt a change in wiring material (from aluminum to copper interconnect layer) alongside a change in dielectric material in
33216-494: Was attributed to the very high power consumption and heat output of the processor. This led to the processor receiving the nickname "PresHot" on forums. In fact, Prescott's power and heat characteristics were only slightly higher than those of Northwood of the same speed and nearly equal to the Gallatin-based Extreme Editions, but since those processors had already been operating near the limits of what
33408-534: Was caused by electromigration . Also based on the Northwood core, the Mobile Intel Pentium 4 Processor - M (also known as the Pentium 4 M ) was released on April 23, 2002, and included Intel's SpeedStep and Deeper Sleep technologies. Its TDP is about 35 watts in most applications. This lowered power consumption was due to lowered core voltage, and other features mentioned previously. Unlike
33600-439: Was clocked at 1.2 GHz at the time) easily outperformed the Pentium 4, which would only catch up if software was re-compiled with SSE2 support. Tom Yager of Infoworld magazine called it "the fastest CPU – for programs that fit entirely in cache". Computer-savvy buyers avoided Pentium 4 PCs due to their price premium, questionable benefit, and initial restriction to Rambus' RDRAM . In terms of product marketing,
33792-460: Was considered thermally acceptable, this still posed a major issue. The release of Prescott also coincided with the launch of LGA 775 and the BTX form factor , which were also criticized. Tests showed that a given Pentium 4 made for LGA 775 consumed more power and produced more heat than the exact same chip in a socket 478 package. The BTX form factor, meanwhile, showed signs of having been designed for
33984-411: Was known as Pentium 4 HT and was introduced to mass market by Gateway in November 2002. On April 14, 2003, Intel officially launched the new Pentium 4 HT processor. This processor used an 800 MT/s FSB (200 MHz physical clock), was clocked at 3 GHz, and had Hyper-Threading technology. This was meant to help the Pentium 4 better compete with AMD's Opteron line of processors. Meanwhile, with
34176-547: Was launched on June 23, 2003 and the final 3.4 GHz version arrived on February 2, 2004. Overclocking early stepping Northwood cores yielded a startling phenomenon. While core voltage approaching 1.7 V and above would often allow substantial additional gains in overclocking headroom, the processor would slowly (over several months or even weeks) become more unstable over time with a degradation in maximum stable clock speed before dying and becoming totally unusable. This became known as Sudden Northwood Death Syndrome (SNDS), which
34368-513: Was not as big of an issue as it is today in device manufacturing. In the 1960s, workers could work on semiconductor devices in street clothing. As devices become more integrated, cleanrooms must become even cleaner. Today, fabrication plants are pressurized with filtered air to remove even the smallest particles, which could come to rest on the wafers and contribute to defects. The ceilings of semiconductor cleanrooms have fan filter units (FFUs) at regular intervals to constantly replace and filter
34560-556: Was particularly so in mid-2002, when AMD's changeover to its 130 nm production process did not help the initial "Thoroughbred A" revision Athlon XP CPUs to clock high enough to overcome the advantages of Northwood in the 2.4 to 2.8 GHz range. The 3.06 GHz Pentium 4 enabled Hyper-Threading Technology that was first supported in Foster-based Xeons. This began the convention of virtual processors (or virtual cores) under x86 by enabling multiple threads to be run at
34752-522: Was released in a time when AMD was asserting near total dominance in the processor performance race, the Pentium 4 Extreme Edition established a new position within Intel's product line, that of an enthusiast oriented chip with the highest-end specifications offered by Intel chips, along with unlocked multipliers to allow for easier overclocking. In this role it has since been succeeded by the Pentium Extreme Edition (The Extreme version of
34944-574: Was released to address the problem of putting a full desktop Pentium 4 processor into a laptop, which some manufacturers were doing. The Mobile Pentium 4 used a 533 MT/s FSB, following the desktop Pentium 4's evolution. Oddly, increasing the bus speed by 133 MT/s (33 MHz) caused a massive increase in TDPs, as mobile Pentium 4 processors emitted 59.8–70 W of heat, with the Hyper-Threading variants emitting 66.1–88 W. This allowed
35136-466: Was seen as a potential low cost alternative to FinFETs. As of 2019, 14 nanometer and 10 nanometer chips are in mass production by Intel, UMC , TSMC, Samsung, Micron , SK Hynix , Toshiba Memory and GlobalFoundries, with 7 nanometer process chips in mass production by TSMC and Samsung, although their 7 nanometer node definition is similar to Intel's 10 nanometer process. The 5 nanometer process began being produced by Samsung in 2018. As of 2019,
35328-486: Was significantly faster and more power-efficient than the former three. In September 2003, at the Intel Developer Forum, the Pentium 4 Extreme Edition (P4EE) was announced, just over a week before the launch of Athlon 64 and Athlon 64 FX . The design was mostly identical to Pentium 4 (to the extent that it would run in the same motherboards), but differed by an added 2 MB of level 3 cache. It shared
35520-475: Was similar to Intel's 10 nm process , thus the conventional notion of a process node has become blurred. Additionally, TSMC and Samsung's 10 nm processes are only slightly denser than Intel's 14 nm in transistor density. They are actually much closer to Intel's 14 nm process than they are to Intel's 10 nm process (e.g. Samsung's 10 nm processes' fin pitch is the exact same as that of Intel's 14 nm process: 42 nm). Intel has changed
35712-647: Was so popular that it dominated the mainframe computer market for decades and left a legacy that is continued by similar modern computers like the IBM zSeries . In 1965, Digital Equipment Corporation (DEC) introduced another influential computer aimed at the scientific and research markets—the PDP-8 . Transistor-based computers had several distinct advantages over their predecessors. Aside from facilitating increased reliability and lower power consumption, transistors also allowed CPUs to operate at much higher speeds because of
35904-399: Was the Intel 4004 , and the first widely used microprocessor, made in 1974, was the Intel 8080 . Mainframe and minicomputer manufacturers of the time launched proprietary IC development programs to upgrade their older computer architectures , and eventually produced instruction set compatible microprocessors that were backward-compatible with their older hardware and software. Combined with
36096-458: Was the N0 stepping Prescott-2M. Intel also marketed a version of their low-end Celeron processors based on the NetBurst microarchitecture (often referred to as Celeron 4 ), and a high-end derivative, Xeon , intended for multi-socket servers and workstations. In 2005, the Pentium 4 was complemented by the more advanced dual-core -brands Pentium D and Pentium Extreme Edition, all were succeeded at
36288-591: Was the Prescott (90 nm) (February 2004), but this feature was not enabled. Intel subsequently began selling 64-bit Pentium 4s using the "E0" revision of the Prescotts, being sold on the OEM market as the Pentium 4, model F. The E0 revision also adds eXecute Disable (XD) (Intel's name for the NX bit ) to Intel 64. Intel's official launch of Intel 64 (under the name EM64T at that time) in mainstream desktop processors
36480-573: Was the considerable time and effort required to reconfigure the computer to perform a new task. With von Neumann's design, the program that EDVAC ran could be changed simply by changing the contents of the memory. EDVAC was not the first stored-program computer; the Manchester Baby , which was a small-scale experimental stored-program computer, ran its first program on 21 June 1948 and the Manchester Mark 1 ran its first program during
36672-413: Was the first to adopt copper interconnects. In 2014, Applied Materials proposed the use of cobalt in interconnects at the 22nm node, used for encapsulating copper interconnects in cobalt to prevent electromigration, replacing tantalum nitride since it needs to be thicker than cobalt in this application. The highly serialized nature of wafer processing has increased the demand for metrology in between
36864-429: Was used in a series of computers capable of running the same programs with different speeds and performances. This was significant at a time when most electronic computers were incompatible with one another, even those made by the same manufacturer. To facilitate this improvement, IBM used the concept of a microprogram (often called "microcode"), which still sees widespread use in modern CPUs. The System/360 architecture
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