INTRODUCTION – INTEGRATE CIRCUIT
An integrated or monolithic circuit is a set of electronic circuits on one small plate (chip) of semiconductor material, normally silicon; this can be made much smaller than discretion circuit made from independent components.
Integrated circuits are used in virtually all electronic equipment today and have revolutionized the world of electronics, computers, mobile phones, and other digital home appliances.
It can be made very compact, having up to several billion transistors and other electronic component.
HISTORY
Integrated Circuit where made possible by experimental discoveries showing that semiconductor devices could perform the functions of vacuum tubes and by mid-20th century technology advancements in semiconductor device fabrication the integration of large numbers of tiny transistors into a small chip was an enormous improvement over the manual assembly of circuits using discrete electronic components.
There are two main advantages of ICs over discrete circuits: Cost and performance. Cost is low because the chips with all their components are printed as a unit by photolithography rather than being constructed one transistor at a time.
Furthermore, much less material is used to construct a packaged I.C. die than to construct a discrete circuit.
Performance is high because the components switch quickly and consume little power (compared to their discrete counterparts) as a result of the small size and close proximity of the components as of 2012, typical chip areas range from a few square millimeters of around 450mm2, with up to 9 million transistors per mm2.
TERMINOLOGY
An integrated circuit is define as a circuit in which all or some of the circuit elements are inseparably associated and electrically interconnected so that it is considered to be indivisible for the purposes of construction and commerce.
Circuits meeting this definition can be constructed using many different technologies – for example, thin-film transistor, thick film technology, or hybrid integrated circuit however, in general usage integrated circuit has since come to refer to the single – piece circuit construction originally known as a monolithic integrated circuit.
INVENTION
Invention of the integrated circuit early developments of the integrated circuit go back to 1949, when the German engineer Werner Jacobi (Siemens A G) file a parent for an integrated-Circuit – like semiconductor amplifying device.
The idea of the integrated circuit was conceived by a Radar scientist working for the Royal Radar establishment of the British ministry of Defence.
Geoffrey W.A. Dummer (1909-2002).
Dummer presented the idea to the public at the symposium on progress in quality electronic components in Washington, D.C on 7 May 1952. He gave many symposia publicly to propagate his ideas, and unsuccessfully attempted to build such a circuit in 1956.
A precursor idea to the I.C. was to create small ceramic squares (Wafers) each one containing a simple miniaturized component.
GENERATIONS
In the early days of integrated circuits, only a few transistors could be placed on a chip, as the scale used was large because of the contemporary technology and manufacturing yields where low by today’s standard.
ADVANCES IN INTEGRATED CIRCUIT
Among the most advanced integrated circuits are the microprocessors which control everything from computers and cellular phones to digital microwave ovens, digital memory chips and application specific Integrated Circuits (ASIC) are examples of other families of integrated circuits that are important to the modern information ping a complex integrated circuit is quite high, when spread across typically millions of production units the individual I.C. cost is minimized.
CLASSIFICATION
Integrated circuits can be classified into analog, digital and mixed signal both analog and digital on the same chip.
Digital Integrated Circuits can contain anywhere from one to millions of logic gates, flip-flops multiplexers, and other circuit in a few square millimeters. The small size of this circuit allows high speed, low power dissipation, and reduced manufacturing cost compared with board-level integration. These digital ICs, typically microprocessor, DSPs, and micro controllers work using binary mathematics to process “one” and “zero” signals.
Analog ICs, such as sensors, power management circuits, and operational amplification, active filtering, demodulation, and mixing analog ICs ease the burden on circuit designers by having expertly designed analog circuits available instead of designing a difficult analog circuit from scratch.
ICs can also combine analog and digital circuits on a single chip to create functions such as A/D Converters and D/A Converters. Such mixed – signal circuits offer smaller size and lower cost but must carefully account for signal interference.
Modern electronic component distributors often further sub-categorize the huge variety of integrated circuits now available:
DIGITAL ICS ARE FURTHER SUB-CATEGORIZED AS
– Logic ICs,
– Memory Chips
– Interface ICs (level shifters, serializer/deserializer, etc),
– Power management ICs and
– Programmable devices.
– Analog ICs are further sub-divided as linear ICs and FIF ICs.
Mixed-signal Integrated Circuits are further sub-categorized as data acquisition ICs (including A/D converters, D/A Converter, digital potentiometer) and clock/timing ICs.
The semiconductors of the periodic table of the chemical elements were identified as the most likely materials for a solid-state vacuum tube. Starting with copper oxide, proceeding to germanium, then silicon the materials where systematically studied in the 1940s and 1950s. Today, silicon monocrystal are the main substrate used for ICs although some 111-v compounds of the periodic table such as gallium arsenide are used for specialized application like LEDS, lasers, solar cells and the highest-speed Integrated Circuits. It took decades to perfect methods of creating crystals without defects in the crystalline structure of the semiconducting material. Semiconductor ICs are fabricated in a layer process which includes these key process steps:
· Imaging
· Deposition
· Etching
The main process steps are supplemented by doping and cleaning.
Mono-crystal silicon wafers (or for special arsenide wafers) are used as the substrate.
Photolithography is used to mark different areas of the substrate to be doped or to have polysilicon, insulators or metal (typically aluminium) tracks deposited on them.
Integrated circuits are composed of many overlapping layers, each defined by photolithography, and normally shown in different colours. Some layers mark where various dopants are diffused into the substrate (called diffusion layers) some define where additional ions are implanted (implant layers), some define the conductors (polysilicon or metal layers) and some define the connections between the conducting layers (via or contact layers) all components are constructed from a specific combination of these layers
In a self-aligned CMOS process, a transistor is formed wherever the gate layer (polysilicon or metal) crosses a diffusion layer.
Capacitive structures, in form very much like the parallel conducing plates of a traditional
Electrical capacitor, are formed according to the area of the “plates”, with insulating material between the plates.
Capacitors of a wide range of sizes are common on ICs. Meandering stripes of varying lengths are sometimes used to form on-chip resistors, though most logic circuits do not need any resistors. The ratio of the length of the resistive structure to it with, combined with its sheet resistivity, determines the resistance more rarely, inductive structures can be built as tiny on-chip coils, or simulated by gyrators. Since a CMOs device only draws current on the transition between logic states, CMOs devices consume much less current than bipolar devices.
A random access memory is the most regular type of integrated circuit; the highest density devices are thus memories; but even a micro-process or will have memory on the chip (see the regular array structure at the bottom of the first image) Although the structures are intricate with widths which have been shrinking for decades the layers remain much thinner than the device widths the layers of material are fabricated much like a photographic process, although used to “expose” a layer of material as they would be too large for the features, thus protons of higher frequencies (typically ultraviolet) are use to create the patterns for each layer. Because each feature is so small, electron microscopes are essential tools for a process engineer who might be debugging a fabrication process each device is tested before packing using automated test equipment (ATE), in a process known as wafer testing, or wafer probing. The wafer is then cut into rectangular blocks, each of which is called a die. Each good die (plural dice, dies, or die) is then connected into a package using aluminium (or gold) bond wires which are thermosonic bonded to pads, usually found around the edge of the die. Thermosonic bonding was first introduced by A. Coucoulas which provided a reliable means of forming these vital electrical connection to the outside hold. After packaging, the devices go through final testing on the same or similar ATE used during wafer probing. Industrial CT scanning can also be used. Test cost can account for over 25% of the cost of fabrication on lower cost products, but can be negligible on low yielding, larger, and/or higher cost devices.
As of 2005, a fabrication facility (commonly known as a semi-conductor fab) costs over USS1 billion to construction. The cost of a fabrication facility rises over time (Rock’s law) because much of the operation is automated. Today, the most advanced processes employed the following techniques:
The wafers are up to 300mm in diameter (wider) than a common dinner plate). Use of 32 nanometer or smaller chip manufacturing process. Intel, IBM, NEC, and AMD are using 32 nanometers for their CPU chips, IBM and AMD introduced immersion lithography for their 45mm processes copper interconnects where copper wiring replaces aluminium for interconnects. Low-k dielectric insulators, silicon on insulator (SOI) stained silicon in a process used by IBM known as strained silicon directly on insulator (SSDOI) multigate devices such as tri-gate transistors being manufactured by Intel from 2011 in their 22mm process.
PACKAGING
The earliest integrated circuits where packaged in ceramic flat packs, which continued to be used by the military for their reliability and small size for many years. Commercial circuit packaging quickly moved to the dual in-line package (DIP), first in ceramic and later in plastic. In the 1980s pin counts of VLSI circuits exceeded the practical limit for DIP packaging leading to pin grid array (PGA) and leadless chip carrier (LCC) packaging appeared in the early 1980s and became popular in the late 1980s, using finger lead pitch with leads formed as either gull-wing or J-lead, as exemplified by small-outline integrated circuit-a carrier which occupies an area about 30-50% less than an equivalent DIP, with a typical thickness that is 70% less. This package has “gull wing” leads pro-ruding from the two long sides and a lead spacing of 0.050 inches.
In the late 1990s, plastic quad flat pack (PQFP) and thin small-outline package (SOP) packages became the most common for high pin count devices, though PGA packages are still often used for high-end microprocessors.
Intel and AMD are currently transitioning from PGA packages on high-end microprocessors to land grid arrays (LGA) packages. Ball grid array (BGA) packages have existed since the 1970s. flip-chip Ball Grid Array packages, which allow for much higher pin count than other package types, were developed in the 1990s. in an FCBGA package the die is mounted up-side-down (flipped) and connects to the package balls via a package substrate that is similar to a printed-circuit board rather than by wires. (FCBGA packages allow an array of input output signals (called Area – 1/0) to be distributed over the entire die rather than being confined to the die periphery.
Traces out of the die, through the package, and into the printed circuit board have very different electrical properties, compared to on-chip signals. They require special design techniques and need much more electric power than signals confined to the chip itself.
When multiple dies are pat in one package, it is called sip, for system in package. When multiple dies are combined on a small substrate, often ceramic, it’s called an MCM, or multi-chip module. The boundary between a big MCM and a small printed circuit board is sometimes fuzzy.
Chip labeling and manufacture date
Most integrated circuits large enough to include identifying information include poor common section: the manufacture’s name or logo, the part number, a part production batch number and/or servel number, and a poor – digit code that identifies when the chip was manufacture. Extremely small surface amount technology parts often bear only a number used in a manufacture’s lookup table to find the chip characteristics. The manufacturing date is commonly represented as a two-digit year followed by a two-digit week code, such that a part bearing the code 8341 was manufactured in week 41 of 1983, or approximately in October 1983. Legal protection of semi-conductor chip layouts.
Integrated circuit layout design protection like most of the other forms of intellectual property, IC layout designs are creations of the human mind, they are usually the result of an enormous investment, both in terms of the time of highly qualified experts, and financially there is a continuing need for the creation of new layout designs which reduce the dimensions of existing integrated circuits and simultaneously increase their functions. The smaller an integrated circuit, the less the material needed for its manufacture, and the smaller the space needed to accommodate it.
Integrated circuits are utilized in a large range of products, including articles of everyday use such as watches, television sets, appliances, automobiles, etc, as well as sophisticated data processing equipment.
The possibility of copying by photographing each layer of an integrated circuit and preparing photomasks for its production on the basis of the photographs obtained is the main reason for the introduction of legislation for the protection of layout designs.
A diplomatic conference was held at a Washington, O.C, in 1989, which adopted a treaty on intellectual property in respect of integrated circuits (IPIC treaty).
The treaty on intellectual property in respect of Integrated Circuits, also called Washington treaty or IPIC Treaty (signed at Washington on 26 may 1989) is currently not in force, but was partially integrated into the TRIPS agreement.
National laws protecting IC layout designs have been adopted in a number of countries. Other developments in the 1980s, programmable logic devices where developed. These devices contain circuits whose logical function and connectivity can be programmed by the user, rather than being fixed by the integrated circuit manufacturer. This allows a single chip to be programmed to implement different LSI type functions such as logic gates, odder and registers, current devices called field-programmable gate arrays can now implement tens of thousands of LSI circuits in parallel and operate up to 1.5 GHz. (citation need) the techniques perfected by the integrated circuit industry over the last three decades have been used to create very small mechanical devices driven by electricity using a technology known as microelectrone chemical systems. These devices are used in a variety of commercial and military applications. Example commercial applications include DLP protectors, inkjet printers, and accelerometers used to deploy automobile airbags.
In the past, radios could not be fabricated in the same low-cost processes as microprocesses as microprocessors. But since 1998, a large number of radio chips have been developed using CMOs processes. Examples include Intel’s DECT cordless phone, or Atheros’s 802. 11cards.
Future developments seem to follow the muticore multi-microprocessor paradigm, already used by the Intel and AMD dual-core processors. Rapport Inc. and BM started shipping the KC256 in 2006, a 256-core microprocessor. Intel, as recently as February-August 2011, unveiled a prototype, “not for commercial sale” chip that bears 80 cores. Each core is capable of handling its own task independently of the others. This is in response to the heat-versus-speed limit that is about to be reached using existing transistor technology (see: terminal design power). This design provides a new challenge to chip programming. Parallel programming languages such as the open source x10 programming language are designed to assist with this task.
Since the early 2000s, the integration of optical functionality into silicon chips has been actively pursued in both academic research and in industry resulting in the successful commercialization of silicon based integrated optical transceivers combining optical devices (modulators, detectors, routing) with CMOs based electronics.
SILICON LABELING AND GRAFFITI
To allow identification during production most silicon chips will have a serial number in one corner. It is also common to add the manufacturer’s logo. Ever since ICs where created, some chip designers have used the silicon surface area for surreptitious, non-functional images or words. These are sometimes referred to as chip art silicon art, silicon graffiti or silicon doodling.
ICs and IC families
The SSS timer IC
The 74 operational amplifier 7400 series IT logic building blocks 4000 series, the CMOs counterpart to the 7400 series (see also. 74HCOO series) Intel 4004, the world’s first microprocessor, which led to the famous 8080 CPU and then the IBM PC’s 8088, 80286, 486 etc
The MOS Technology
6502 and zilog z80 microprocessors used in many home computers of the early 1980s the Motorola 680 series of computer-related chips, leading to the 68000 and 8800 series (used in some Apple Computers and in the 1980s commodore Amiga series). The LM – series of analog integrated circuits.
IC Device Technologies
BCDMOS
BICMOS Bipolar/CMOS
Mixed technology
Bipolar junction transfer integrated injection
Logic
LDMOS
Logic family
MOSFET metal-oxide-silicon field effect Transistor multi-threshold CMOs (MTCMOS)
Depletion – load NMOS logic
SIGE – Silicon-Germanium technology.
REFERENCES
– Andrew Wylie (2009 “the first monolithic integrated circuit”
Retrieved 14 March 2011.
– Antone consalves (2007) Samsung begging production of 16 – Gb flash”
– A.H.D Graham (2011) commercialization of CMOs integrated circuit technology in multi-electrode arrays for neuro-science and cell Based Biosensors
– Arjun N. Saxena (2009) invention of integrated circuits.
– Ginz-berg. Eli (1976) Economic impact of large public programs:
The NASA experience Olympus publishing company.
– George Rostky (2008) micromodules: the ultimate package.
– Mindell, David A (2008) Digital Apollo: Human and machine in space flight. The MIT press
– Nobel web AB (2008) (The Nobel prize in physics)
– Peter Clarke (2005) ; Intel enters billions transistors processors.
– Winston, Brian 1998) media technology and society