PREMLILA VITHALDAS POLYTECHNIC S. N. D. T. Women’s University, Juhu Campus, Santacruz (West), Mumbai- 400 049. Maharashtra (INDIA).

Integrated Circuit

PREPARED BY

Miss. Rohini A. Mane (G. R. No.: 15070113) Miss. Anjali J. Maurya (G. R. No.: 15070114) Miss. Tejal S. Mejari (G. R. No.: 15070115) . .

Diploma in Electronics: Semester VII (June - November 2018)

Introduction: History:

The separately manufactured components like An is a thin slice of silicon resistor, capacitor, diode, and transistor are joined by or sometimes another material that has been specially wires or by printed circuit boards (PCB) to form processed so that a tiny electric circuit is etched on its circuit. These circuits are called discrete circuits and surface. The circuit can have many millions of they have following disadvantages. microscopic individual elements, including 1. In a large electronic circuit, there may be very transistors, resistors, capacitors, and conductors, all large number of components and as a result electrically connected in a certain way to perform the discrete assembly will occupy very large some useful function. space. 2. They are formed by soldering which causes a problem of reliability. To overcome these problems of space conservation and reliability the integrated circuit were developed(IC).

Figure2 The first Integrated circuit

The first integrated circuits were based on the idea that the same process used to make clusters of transistors on silicon wafers might be used to make a functional circuit, such as an amplifier circuit or a logic circuit. Slices of the semiconductor Figure1 Integrated Circuit materials silicon and germanium were already being printed with patterns, the exposed surfaces etched with An integrated circuit (IC), sometimes called a chemicals, and then the pattern removed, leaving chip or microchip, is a semiconductor wafer on which dozens of individual transistors, ready to be sliced up thousands or millions of tiny resistors, capacitors, and and packed individually. But wires, a few resistors and transistors are fabricated. An IC can function as an capacitors might later connect those same transistors amplifier, oscillator, timer, counter, computer to make a circuit. memory, or microprocessor. A particular IC is categorized as either linear (analog) or digital, The idea occurred to a number of inventors at depending on its intended application. the same time, but the first to accomplish it were Jack 1. In IC, the various components are integral Kilby of Texas Instruments and of part of a small semiconductor chip and the Fairchild Semiconductor Incorporated. The idea individual components cannot be removed caught on like wildfire because the integrated circuit for repair and replacement as in discrete had many of the advantages that had made the circuit. transistor attractive earlier. These advantages included 2. It combines both active elements like diode small size, high reliability, low cost, and small power and transistor with passive components like consumption. However, these circuits were difficult to resistor and capacitors in monolithic circuit. make because if one component of the chip was faulty, Their size is very small. To see connections the whole chip was ruined. As engineers got better and between their various components, a better at squeezing more and more transistors and microscope is needed. other components onto a single chip, the problems of 3. All the components are formed within the actually making these chips increased. When the chip and no components is seen projected transistors were shrunk down to microscopic size, above the surface of the chip. even the smallest bit of dust could ruin the chip. That's why today, chips are made in special "clean rooms"

1 where workers wear the "bunny suits" that we often And you probably know Texas Instruments see on TV. because—at one point—you took a math class and used one of the company’s calculators. Oddly enough, Compared to the original integrated circuit, Kilby gets credit for that one as well. which was a simple device with just a few components, the number of components on today's' integrated circuits is amazing. In the 1960s, an engineer named Gordon Moore predicted that the number of elements on a chip would double every year (later revised to every two years) into the foreseeable future. "Moore's Law" has held true so far. By the beginning of the twenty-first century, the Intel Pentium chip had over 100 million transistors on it, with the total number of components including resistors, capacitors, and conductors being even larger. Like many inventions, the integrated circuit was really a matter of time. Kilby drew upon the works of an Englishman, Geoffrey Dummer, when coming up with the idea of the integrated circuit. In the early 1950s, Dummer proposed electronics built from a single block of components, but he lacked the technique to make it into a reality. Figure4 A look inside Kilby’s original Texas Instruments electronic handheld calculator.

He and two co-workers, Jerry Merryman and James Van Tassel, developed the electronic handheld calculator because Texas Instruments needed a way to sell the public on the consumer benefits of the integrated circuit.

The beginnings of the IC really started with the inherent limitations of the vacuum tube, a large, bulky device that preceded the transistor which eventually led to the microchip. Vacuum tubes worked as an electronic circuit, but they required warming up before they could operate. Plus, they were quite vulnerable to being damaged or destroyed even by Figure3 Kilby and Noyce received the Draper Prize in minor bumps or impacts. 1989. With the limitations in mind, German Then there was Robert Noyce (Noyce and engineer Werner Jacobi filed a patent in 1949 for a Kilby received the Draper Prize together in 1989). semiconductor that operated similarly to the current Noyce, often referred to as “the Mayor of Silicon integrated circuit. Jacobi lined up five transistors and Valley,” is credited as the co-inventor of the integrated used them in a three-stage arrangement on an circuit, and for good reason. amplifier. The result as Jacobi recognized was the ability to shrink devices such as hearing aids and make Noyce came up with the same idea them cheaper to produce. completely independently, used silicon instead of germanium (silicon operates at higher temperatures), Despite Jacobi’s invention, there appeared to and had an altogether more-refined design. be no immediate interest. Three years later, Geoffrey Dummer who worked for the Royal Oh, and he went on to co-found Intel in 1968 Establishment as part of the Ministry of Defence in with colleague Gordon Moore. Intel, of course, created Britain proposed the first fully conceived idea for the the first microprocessor, equally important to modern integrated circuit. However, despite giving lectures computing. about his ideas, he was never able to build one

2 successfully. It was the failure to actually create an IC photo). Geoffrey William Arnold Dummer (1909– on his own that led to the movement towards the chip 2002) is a British electronics author and consultant, overseas to America. who passed the first radar trainers and became a pioneer of reliability engineering at the Invention: Telecommunications Research Establishment in Malvern in the 1940s. His work with colleagues at TRE led him to the belief that it would be possible to fabricate multiple circuit elements on and into a substance like silicon. In 1952 he presented his work at a conference in Washington, DC, in which he states: “With the advent of the transistor and the work on semi-conductors generally, it now seems possible to envisage electronic equipment in a solid block with no connecting wires. The block may consist of layers of insulating, conducting, rectifying and amplifying materials, the electronic functions being connected directly by cutting out areas of the various layers”. This is now generally accepted as the first public description of an integrated circuit. Figure5 Robert Noyce (left) and (Courtesy of Intel and Texas Instruments) At a later date Dummer said, “It seemed so logical to me; we had been working on smaller and As with many inventions, several people had smaller components, improving reliability as well as the idea for an integrated circuit at almost the same size reduction. I thought the only way we could ever time. In 1950s many inventors realize, that despite of attain our aim was in the form of a solid block. You the fact, that transistors had become commonplace in then do away with all your contact problems, and you everything from radios to phones to , and have a small circuit with high reliability. And that is that transistors were smaller than vacuum tubes, for why I went on with it. I shook the industry to the bone. some of the newest electronics, they weren't small I was trying to make them realise how important its enough. There was a limit on how small you could invention would be for the future of microelectronics make each transistor, since after it was made it had to and the national economy”. be connected to wires and other electronics. The In September 1957, Dummer presented a model to transistors were already at the limit of what steady illustrate the possibilities of solid-circuit techniques— hands and tiny tweezers could handle. So, scientists a flip-flop in the form of a solid block of wanted to make a whole circuit—the transistors, the semiconductor material, suitably doped and shaped to wires, everything else they needed—in a single blow. form four transistors. Four resistors were represented If they could create a miniature circuit in just one step, by silicon bridges, and other resistors and capacitors all the parts could be made much smaller. were deposited in film form directly onto the silicon block with intervening insulating films.

Dummer's ideas however remained unrealized and relatively unknown, because the UK military failed to perceive any operational requirements for ICs, and UK companies were unwilling to invest their own money. Dummer later said: “I have attributed it to war-weariness in one of my books, but that is perhaps an excuse. The plain fact is that nobody would take the risk. The Ministry wouldn’t place a contract because they hadn’t an application. The applications people wouldn’t say we want it, because they had no experience with it. It was Figure6 British engineer Geoffrey Dummer a chicken-and-egg situation. The Americans took financial gambles, whereas this was very slow in this The first man, who must be credited for the country”.And the Americans were again faster and conceptualisation of the integrated curcuit, is the took financial gambles. British engineer Geoffrey Dummer (see yhe nearby

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One day in late July of 1958, the engineer millimetres in size ), was shown off for the first time Jack Kilby (see biography of Jack Kilby) was sitting in March, 1960. alone at a small, but innovative company in Dallas, Texas—Texas Instruments. In 1954 the company had been involved with manufacturing the first transistor pocket radio, which was enormously successful. Executives at Texas Instruments believed that the possibilities of electronic circuits were nearly endless. In May of 1954 company engineers perfected a process for making transistors out of silicon—an improvement which made them much less prone to fail when they got hot. In their research they discovered that several electrical components could be built from silicon, although at the time they were only interested Figure7 The original integrated circuit of Jack Kilby in transistors. But over in California, another man had Kilby had been hired only a month earlier and similar ideas. In January of 1959, Robert Noyce (see so he wasn't able to take vacation time when his biography) was working at a small startup practically everyone else did. The halls were deserted, company—Fairchild Semiconductor, which he and 7 and he had lots of time to think. As he remembered of his colleagues established in 1957, leaving later: "As a new employee, I had no vacation time Shockley Semiconductor. He also realized a whole coming and was left alone to ponder the results of an circuit could be made on a single chip. While Kilby IF amplifier exercise. The cost analysis gave me my had hammered out the details of making individual first insight into the cost structure of a semiconductor components, Noyce thought of a much better way to house." It suddenly occurred to him that all parts of a connect the parts. That spring, Fairchild began a push circuit, not just the transistor, could be made out of to build what they called "unitary circuits" and they silicon. At the time, nobody was making capacitors or also applied for a patent on the idea. Knowing that TI resistors out of semiconductors. If it could be done had already filed a patent on something similar, then the entire circuit could be built out of a single Fairchild wrote out a highly detailed application, crystal—making it smaller and much easier to hoping that it wouldn't infringe on TI's similar device. produce. Kilby's solution to this problem has come to be called the monolithic idea. He listed all the All that detail paid off. On April 25, 1961, the electrical components that could be built from silicon: patent office awarded the first patent for an integrated transistors, diodes, resistors and capacitors. circuit to Robert Noyce (see the U.S. patent 2981877 patent of Noyce) while Kilby's application, filed 5 What was the reaction of his colleagues? months earlier than Noyce's, was still being analyzed Kilby recalled: There were a number of objections. and the patent was granted as late as June, 1964 (see Most people thought that you would never be able to the U.S. patent 3138743 patent of Kilby). Today, both make them in quantity. At that time less than 10 men are acknowledged as having independently percent of the transistors at the end of the line were conceived of the idea, but the real acknowledgement likely to be good. The thought that you would put came too late, in 2000, when only Kilby became a several on a chip seemed like madness. Nobel Prize laureate for his invention of the integrated circuit, while Noyce died in 1990 and didn't manage to Kilby then conceived the idea of constructing be honored with this prestigious award. a single device with all the needed parts that could be made of silicon and soldering it to a circuit board. He The companies Fairchild Electronics and understood that if he could eliminate the wires Texas Instruments had a court fight that was not settled between the parts, he could squeeze more parts into a until 1966, by which time integrated circuit chips had smaller space, thus solving the obstacle of become a multi-billion dollar industry. In the summer manufacturing complex transistor circuits. When he of 1966 executives of the two companies had made an presented this smash idea to his boss, he liked it, and agreement to share ownership by granting production told him to get to work. By September 12, Kilby had licenses to each other. Any other company that wanted built a working model (see the lower photo), and on to produce integrated circuits had to pay both Texas February 6th, Texas Instruments filed a patent. Their Instruments and Fairchild. As for Kilby, the scientific first Solid Circuit the size of a pencil point (11-by-1.5- community informally agreed that both he and Noyce

4 had invented the chip and that they both deserved made feasible by the microchip. Within a year Kilby credit. and his colleagues Merryman, and Van Tassel had a working prototype, and a year later they filed for a Kilby and Texas Instruments had made a big patent. The resulting first in the world electronic hand- breakthrough. But while the U.S. Air Force showed held calculator (see the lower photo), of which Kilby some interest in TI's integrated circuit, industry is a co-inventor, successfully commercialized the reacted skeptically. Indeed the IC and its relative integrated circuit in 1967. The so called Pocketronic merits "provided much of the entertainment at major was launched on April 14 1971, weighed a little over technical meetings over the next few years," as Kilby 1 kg, cost $150, and could only perform the four main wrote later. arithmetical functions. Displaying the output remained a problem. Light-emitting diode LED (light-emitting diode) technology, which became the standard for calculator display, was not yet advanced enough to use. So Kilby invented a new thermal printer with a low-power printing head, that pressed the paper readout against a heated digit.

Figure8 SN510

Since TI and Fairchild were the co-inventors of the IC, one might expect that they would release the first commercial devices, and in fact this was so. In March, 1960, Texas Instruments announced the introduction of the earliest product line of integrated logic circuits. TI's trade name is Solid Circuits for this line. This family, called the series 51, utilized the modified DCTL circuit and the SN510 and SN 514, were the first integrated circuits to orbit the Earth, Figure9 The First Electronic Handheld Calculator, aboard the IMP satellite, launched by the US on invented at Texas Instruments in 1967 by Jack Kilby, November 27, 1963 (see the nearby photo). Fairchild's Jerry Merryman, and James Van Tassel (Courtesy of prototype chips were announced in November 1960, Texas Instruments) and the company had introduced its first commercial integrated circuit, the same device as Dummer's a Terminology: decade ago, a flip-flop (the basic storage element in computer logic), at an industry convention in New A circuit in which all or some of the circuit York in March 1961. Soon other firms began to elements are inseparably associated and electrically develop ICs, i.e. Motorola and Signetics, which interconnected so that it is considered to be indivisible announced their first chips in 1962. for the purposes of construction and commerce.

The integrated circuit first won a place in the Circuits meeting this definition can be military market through programs such as the first constructed using many different technologies, computer using silicon chips for the Air Force in 1961 including thin-film transistors, thick-film and the Minuteman Missile in 1962. Recognizing the technologies, or hybrid integrated circuits. However, need for a "demonstration product" to speed in general usage integrated circuit has come to refer to widespread use of the IC, Patrick Haggerty, former TI the single-piece circuit construction originally known chairman, challenged Kilby to design a calculator as as a monolithic integrated circuit powerful as the large, electro-mechanical desktop models of the day, but small enough to fit in a coat Arguably, the first examples of integrated pocket. In 1965, Kilby was put in charge of directing circuits would include the Loewe 3NF. Although far a team to develop the world's first pocket calculator,

5 from a monolithic construction, it certainly meets the definition given above.

Designing: The cost of designing and developing a complex integrated circuit is quite high, normally in the multiple tens of millions of dollars.This only makes economic sense if production volume is high, so the non-recurring engineering (NRE) costs are spread across typically millions of production units.

Modern semiconductor chips have billions of components, and are too complex to be designed by hand. Software tools to help the designer are essential. Electronic Design Automation (EDA), also referred to as Electronic Computer-Aided Design (ECAD), is a category of software tools for designing electronic systems, including integrated circuits. The tools work together in a design flow that engineers use to design and analyze entire semiconductor chips.

Types of Integrated Circuits:

There are different types of ICs; classification of Integrated Circuits is done based on various criteria. A few types of ICs in a system are shown in the below figure with their names in a tree format.

Figure11 Digital Integrated Circuits

Figure10 Different Types of ICs The above figure shows the steps involved in designing a typical digital integrated circuits. These Based on the intended application, the IC are digital ICs are frequently used in the computers, classified as analog integrated circuits, digital microprocessors, digital signal processors, computer integrated circuits and mixed integrated circuits. networks and frequency counters. There are different types of digital ICs or types of digital integrated 1. Digital Integrated Circuits circuits, such as programmable ICs, memory chips, logic ICs, power management ICs and interface ICs.. The integrated circuits that operate only at a few defined levels instead of operating over all levels 2. Analog Integrated Circuits of signal amplitude are called as Digital ICs and these are designed by using multiple number of digital logic The integrated circuits that operate over a gates, multiplexers, flip flops and other electronic continuous range of signal are called as Analog ICs. components of circuits.These logic gates work with These are subdivided as linear Integrated Circuits binary input data or digital input data, such as 0 (low (Linear ICs) and Radio Frequency Integrated Circuits or false or logic 0) and 1 (high or true or logic 1). (RF ICs). In fact, the relationship between the voltage and current maybe nonlinear in some cases over a long range of the continuous analog signal.

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Figure12 Analog Integrated Circuits Figure13 Mixed Integrated Circuits The frequently used analog IC is an This mixed-signal Systems-on-a-chip is a operational amplifier or simply called as an op-amp, result of advances in the integration technology, which similar to the differential amplifier, but possesses a enabled to integrate digital, multiple analog and RF very high voltage gain. It consists of very less number functions on a single chip. of transistors compared to the digital ICs, and, for developing analog application specific integrated circuits (analog ASICs), computerized simulation General types of integrated circuits (ICs) include tools are used. the following:

3. Mixed Integrated Circuits 1. Logic Circuits:

The integrated circuits that are obtained by the combination of analog and digital ICs on a single chip are called as Mixed ICs. These ICs functions as Digital to Analog converters, Analog to Digital converters (D/A and A/D converters) and clock/timing ICs. The circuit depicted in the above figure is an example of mixed integrated circuit which is a photograph of the 8 to 18 GHz self-healing radar receiver.

Figure14 Logic Circuits

These ICs are designed using logic gates-that work with binary input and output (0 or 1). These are mostly used as decision makers. Based on the logic or truth table of the logic gates, all the logic gates connected in the IC give an output based on the circuit connected inside the IC- such that this output is used for performing a specific intended task. A few logic ICs are shown above.

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2. Comparators: 5. Operational amplifiers

Figure15 Comparators

The comparator ICs are used as comparators Figure18 Operational amplifiers for comparing the inputs and then to produce an output based on the ICs’ comparison. The operational amplifiers are frequently used ICs, similar to the audio amplifiers which are used for the audio amplification. These op-amps are 3. Switching ICs used for the amplification purpose, and these ICs work similar to the transistor amplifier circuits. The pin configuration of the 741 op-amp IC is shown in the above figure.

6. Timer ICs Figure16 Switching ICs

Switches or Switching ICs are designed by using the transistors and are used for performing the switching operations. The above figure is an example showing an SPDT IC switch.

4. Audio amplifiers

Figure19 Timer ICs Timers are special purpose integrated circuits used for the purpose of counting and to keep a track of time in intended applications. The block diagram of the internal circuit of the LM555 timer IC is shown in the above circuit.

Figure17 Audio amplifiers Based on the method or techniques used in The audio amplifiers are one of the many manufacturing them, types of ICs can be divided types of ICs, which are used for the amplification of into three classes: the audio. These are generally used in the audio speakers, television circuits, and so on. The above 1. Thin and thick film ICs circuit shows the low- voltage audio amplifier IC. 2. Monolithic ICs 3. Hybrid or multichip ICs

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Below is the simple explanation of different In monolithic ICs, the discrete components, types of ICs as mentioned above. the active and the passive and also the interconnections between then are formed on a silicon 1. Thin and Thick ICs: chip. The word monolithic is actually derived from two Greek words “mono” meaning one or single and In thin or thick film ICs, passive components Lithos meaning stone. Thus monolithic circuit is a such as resistors, capacitors are integrated but the circuit that is built into a single crystal diodes and transistors are connected as separate components to form a single and a complete circuit. Thin and thick ICs that are produced commercially are merely the combination of integrated and discrete (separate) components.

Thick and thin ICs have similar characteristics, similar appearance except the method of film deposition. Method of deposition of films distinguished Thin ICs from Thick ICs. Figure21 Monolithic IC in Plastic Package

Monolithic ICs are the most common types ICs in use today. Its cost of production is cheap and is reliable. Commercially manufactured ICs are used as amplifiers, voltage regulators, in AM receivers, and in computer circuits. However, despite all these advantages and vast fields of application of monolithic ICs, it has limitations. The insulation between the components of monolithic ICs is poor. It also have low power rating, fabrication of insulators is not that possible and so many other factors.

3. Hybrid or Multi chip ICs

Figure20 Hybrid or multi chip IC As the name implies, “Multi”, more than one individual chips are interconnected. The active Thin film ICs are made by depositing films of components that are contained in this kind of ICs are a conducting material on a glass surface or on a diffused transistors or diodes. The passive components ceramic base. By varying the thickness of the films are the diffused resistors or capacitors on deposited on the materials having different resistivity, Passive electronic components like resistors and capacitors can be manufactured. a single chip.

In Thick film ICs, silk printing technique is used to create the desired pattern of the circuit on a ceramic substrate. Thick-film ICs are sometimes referred to as printed thin-film.

The screens are actually made of fine stainless steel wire mesh and the links (connections) are pastes having conductive, resistive or dielectric properties. The circuits are fired in a furnace at a high temperature so as to fuse the films to the substrate after printing. Figure22 Hybrid or multi chip IC's These components are connected by metalized 2. Monolithic ICs patterns. Hybrid ICs are widely used for high power-

9 amplifier applications from 5W to more than 50W. Its Step2: Epitaxial growth: performance is better than that of monolithic ICs.

Fabrication of IC:

Figure25 Epitaxial growth

It means the growing of single silicon crystal upon original silicon substrate. A uniform layer of silicon dioxide is formed on the surface of wafer.

Step3: Masking

Figure23 Fabrication of IC's

Step1: Wafer production

Figure26 Masking

To protect some area of wafer when working Figure24 Wafer Production on another area, a process called photolithography is used. The process of photolithography includes The first step is wafer production. The wafer masking with a photographic mask and photo etching. is a round slice of semiconductor material such as A photoresist film is applied on the wafer. The wafer silicon. Silicon is preferred due to its characteristics. It is aligned to a mask using photo aligner. Then it is is more suitable for manufacturing IC. It is the base or exposed to ultraviolet light through mask. Before that substrate for entire chip. First purified polycrystalline the wafer must be aligned with the mask. Generally, silicon is created from the sand. Then it is heated to there are automatic tools for alignment purpose. produce molten liquid. A small piece of solid silicon is dipped on the molten liquid. Then the solid silicon Step4: Etching (seed) is slowly pulled from the melt. The liquid cools to form single crystal ingot. A thin round wafer of silicon is cut using wafer slicer. Wafer slicer is a precise cutting machine and each slice having thickness about .01 to .025 inches. When wafer is sliced, the surface will be damaged. It can be smoothening by polishing. After polishing the wafer, it must thoroughly clean and dried. The wafers are Figure27 Etching cleaned using high purity low particle chemicals .The It removes material selectively from the silicon wafers are exposed to ultra pure oxygen. surface of wafer to create patterns. The pattern is defined by etching mask. The parts of material are protected by this etching mask. Either wet (chemical) or dry (physical) etching can be used to remove the unmasked material. To perform etching in all directions at same time, isotropic etching will be used. Anisotropic etching is faster in one direction. Wet

10 etching is isotropic, but the etching time control is than atomic diffusion process. It does not require difficult. Wet etching uses liquid solvents for masking and this process is very precise. First it points removing materials. It is not suited to transfer pattern the wafer that where it is needed and shoot the dopants with submicron feature size. It does not damage the to the place where it is required. material. Dry etching uses gases to remove materials. It is strongly anisotropic. But it is less selective. It is Step8: Metallization: suited to transfer pattern having small size. The remaining photoresist is finally removed using additional chemicals or plasma. Then the wafer is inspected to make sure that the image is transferred from mask to the top layer of wafer.

Step5: Doping Figure29 Metallization To alter the electrical character of silicon, atom with one less electron than silicon such as boron It is used to create contact with silicon and to and atom with one electron greater than silicon such as make interconnections on chip. A thin layer of phosphorus are introduced into the area. The P-type aluminum is deposited over the whole wafer. (boron) and N-type (phosphorous) are created to Aluminum is selected because it is a good conductor, reflect their conducting characteristics. Diffusion is has good mechanical bond with silicon, forms low defined as the movement of impurity atoms in resistance contact and it can be applied and patterned semiconductor material at high temperature. with single deposition and etching process. Step9: Making successive layers: Step6: Atomic diffusion:

In this method p and n regions are created by adding dopants into the wafer. The wafers are placed in an oven which is made up of quartz and it is surrounded with heating elements. Then the wafers are heated at a temperature of about 1500-2200°F. The inert gas carries the dopant chemical. The dopant and Figure30 Making successive layer gas is passed through the wafers and finally the dopant will get deposited on the wafer. This method can only The process such as masking, etching, doping be used for large areas. For small areas it will be will be repeated for each successive layers until all difficult and it may not be accurate. integrated chips are completed. Between the components, silicon dioxide is used as insulator. This process is called chemical vapor deposition. To make Step7: Ion implantation: contact pads, aluminum is deposited. The fabrication includes more than three layers separated by dielectric layers. For electrical and physical isolation a layer of solid dielectric is surrounded in each component which provides isolation. It is possible to fabricate PNP and NPN transistor in the same silicon substrate. To avoid damage and contamination of Figure28 Ion implantation circuit, final dielectric layer (passivation) is deposited. After that, the individual IC will be tested for electrical This is also a method used for adding function. Check the functionality of each chip on dopants. In this method, dopant gas such as phosphine wafer. Those chips are not passed in the test will be or boron trichloride will be ionized first. Then it rejected. provides a beam of high energy dopant ions to the specified regions of wafer. It will penetrate the wafer. Step10: Assembly and packaging: The depth of the penetration depends on the energy of the beam. By altering the beam energy, it is possible Each of the wafers contains hundreds of to control the depth of penetration of dopants into the chips. These chips are separated and packaged by a wafer. The beam current and time of exposure is used method called scribing and cleaving. The wafer is to control the amount of dopant. This method is slower similar to a piece of glass. A diamond saw cut the

11 wafer into single chips. The diamond tipped tool is 5. Ultra Large Scale Over 1 million used to cut the lines through the rectangular grid which Integration (ULSI). separates the individual chips. The chips that are failed in electrical test are discarded. Before packaging, remaining chips are observed under microscope. The good chip is then mounted into a package. Thin wire 1. SSI: is connected using ultrasonic bonding. It is then encapsulated for protection. Before delivered to The first integrated circuits contained only a customer, the chip is tested again. There are three few transistors(less than 100 components about 10 configurations available for packaging. They are metal gates). Called "small-scale integration" (SSI), digital can package, ceramic flat package and dual in line circuits containing transistors numbering in the tens package. For military applications, the chip is provided a few logic gates for example, while early assembled in ceramic packages. The complete linear ICs such as the Plessey SL201 or the Philips integrated circuits are sealed in anti-static plastic bags. TAA320 had as few as two transistors.

SSI circuits were crucial to early aerospace Key features: projects, and aerospace projects helped inspire development of the technology. Both the Minuteman  Equips the IC designer with the knowledge to missile and Apollo program needed lightweight digital effectively search for and interpret prior art computers for their inertial guidance systems; the  Explains technical contents of semiconductor Apollo guidance computer led and motivated the and IC design in an interesting and non- integrated-circuit technology, while the Minuteman technical manner making it valuable as well missile forced it into mass-production. The to IP practitioners Minuteman missile program and various other Navy  Addresses the legal knowledge needed by IC programs accounted for the total $4 million integrated inventors to avoid the risk of IP infringement circuit market in 1962, and by 1968, U.S. Government litigation space and defense spending still accounted for 37% of  Illustrates concepts through case studies and the $312 million total production. The demand by the examples and includes crucial and valuable U.S. Government supported the nascent integrated search links circuit market until costs fell enough to allow firms to  Covers IC design protection focusing on the penetrate the industrial and eventually the consumer markets of the USA, UK, EC, and Asia markets. The average price per integrated circuit Pacific dropped from $50.00 in 1962 to $2.33 in 1968. Integrated circuits began to appear in consumer Generation of IC: products by the turn of the decade, a typical application being FM inter-carrier sound processing in television receivers. Sr. Level of integration Number of active No. devices per chip 2. MSI:

The next step in the development of 1. Small Scale Less than 100 integrated circuits, taken in the late 1960s, introduced Integration (SSI). devices which contained hundreds of transistors on each chip, called "medium-scale integration" (MSI). It 2. Medium Scale 100-10,000 contains less than 500 components or have more than Integration (MSI). 10 but less than 100 gates.

3. Large Scale 1,000-100,000 3. LSI: Integration (LSI). Here number of components is between 500 4. Very Large Scale Over 100,000 and 300000 or have more than 100 gates. Integration (VLSI). 4. VLSI: The final step in the development process, starting in the 1980s and continuing through the present, was "very large-scale integration" (VLSI).

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The development started with hundreds of thousands 13. The reduction in power consumption is of transistors in the early 1980s, and continues beyond achieved due to extremely small size of IC. several billion transistors as of 2009. Disadvantages of IC: Multiple developments were required to achieve this increased density. Manufacturers moved 1. In an IC the various components are part of a to smaller design rules and cleaner fabrication small semiconductor chip and the individual facilities, so that they could make chips with more component or components cannot be transistors and maintain adequate yield. The path of removed or replaced, therefore, if any process improvements was summarized by the component in an IC fails, the whole IC has to International Technology Roadmap for be replaced by a new one. Semiconductors (ITRS). Design tools improved 2. Coils or indicators cannot be fabricated. enough to make it practical to finish these designs in a 3. It can be handle only limited amount of reasonable time. The more energy efficient CMOS power. replaced NMOS and PMOS, avoiding a prohibitive 4. High grade P-N-P assembly is not possible. increase in power consumption. 5. It is difficult to be achieved low temperature

coefficient. In 1986 the first one megabit RAM chips 6. The power dissipation is limited to 10 watts. were introduced, which contained more than one 7. Low noise and high voltage operation are not million transistors. Microprocessor chips passed the easily obtained. million transistor mark in 1989 and the billion 8. Inductors and transformers are needed transistor mark in 2005. The trend continues largely connecting to exterior to the semiconductor unabated, with chips introduced in 2007 containing chip as it is not possible to fabricate inductor tens of billions of memory transistors. and transformers on the semiconductor chip

surface. It contain more than 300000 component per 9. Inductors cannot be fabricated directly. chip. 10. Low noise and high voltage operation are not 5. ULSI easily obtained. 11. Quite delicate in handling as these cannot It contains more than 1500000 components per withstand rough handling or excessive heat. chip.

Advantages of IC: Uses of IC’s: IC's are of Linear, digital and mixed types. Linear 1. Cost reduction due to batch processing IC's also known as analog Integrated circuits are 2. Improved functional performance used in: 3. Increases system reliability due to the  Power amplifiers elimination of soldered joints. 4. Matched devices.  Small-signal amplifiers 5. Miniaturization and hence increased  Operational amplifiers equipment density  Microwave amplifiers 6. The entire physical size of IC is extremely  RF and IF amplifiers small than that of discrete circuit.  Voltage comparators 7. The weight of an IC is very less as compared  Multipliers entire discrete circuits.  Radio receivers 8. Because of their smaller size it has lower  Voltage regulators power consumption. Digital IC's are mostly used in computers. They are 9. It can easily replace but it can hardly repair, also referred as switching circuits because their in case of failure. input and output voltages are limited to two levels 10. Because of an absence of parasitic and - high and low i.e. binary. They include: capacitance effect it has increased operating  Flip-flops speed.  Logic gates 11. Temperature differences between  Timers components of a circuit are small.  Counters 12. It has suitable for small signal operation.  Multiplexers

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 Calculator chips Reference Links:  Memory chips  Clock chips http://www.tech-faq.com/integrated-circuit.html  Microprocessors https://anysilicon.com/history-integrated-circuit/  Microcontrollers http://www.circuitstoday.com/integrated-circuits  Temperature sensors http://www.answers.com www.tech-faq.com/integrated-circuit.html Applications: https://www.daenotes.com/electronics/devices- circuits/integrated-circuits-ic Applications for integrated circuits are as http://history- varied as the imagination of the designers. Within computer.com/ModernComputer/Basis/IC.html limits, anything that can be designed and built with http://earthsky.org/human-world/this-date-in-science- discrete components can be put into an IC. Audio microchip-patent amplifier, video processors, logic, memory, switches, https://www.pcworld.com/article/2048664/the- radio frequency encoders and decoders are just a few legend-of-jack-kilby-55-years-of-the-integrated- examples. The range of IC applications is vast and circuit.html growing daily. One of the major applications is https://ethw.org/Integrated_Circuits computing. Computers that once had thousands of https://www.elprocus.com/how-integrated-circuits- transistors have been reduced to a handful of ICs. The work-physically/ early computers that were the size of a building are https://www.elprocus.com/different-types-of- now outperformed in almost every way by laptops and integrated-circuits/ even handheld computers because of the use if ICs https://www.mepits.com/tutorial/384/vlsi/steps-for- The applications of a ICs includes the following: ic-manufacturing https://www.edgefx.in/understanding-cmos-  Power amplifiers fabrication-technology/  Small-signal amplifiers  Operational amplifiers  Microwave amplifiers  RF and IF amplifiers  Voltage comparators  Multipliers  Radio receivers  Voltage regulators  Radar  Wristwatches  Televisions  Juice Makers  PC  Video Processors  Audio Amplifiers  Memory Devices  Logic Devices  Radio Frequency Encoders and Decoders

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Premlila Vithaldas Polytechnic S. N. D. T. WOMEN’S UNIVERSITY Sir Vithaldas Vidyavihar, Juhu Road Santacruz (W), Mumbai- 400 049 Tel. +91-22-2660-8676, +91-22-2660-7668 (Fax). e-mail: [email protected] Website: www.pvpsndt.org