INTRODUCTION
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
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
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