Up until this decade, integrated circuit design was an activity generally only undertaken by engineers in the large electronics companies or IC foundries. A major change has occurred in this decade however, with the ready availability of sophisticated CAD tools, powerful personal computers, and multi-project wafers, all at a relatively low cost, which allow even small companies to incorporate custom-designed application-specific integrated circuits (ASICs) in their products. This book is an introductory text which aims to cover all aspects of IC design, fabrication, and test.

Chip architectures, technologies, and both digital and analogue building blocks are discussed, along with a discussion of the CAD tools available to help designers, and how the major problem of testing fabricated chips is tackled. The book concludes with lengthy appendices on the fabrication process, and an example student project taught by the author. A small number of exercises are given at the end of each chapter.

This book is most suitable for second-year undergraduates on electronic engineering courses with some experience of electronic design using discrete devices, but might also be of interest to graduates from other disciplines who require clarification of the many terms and concepts used by IC designers.

Readers should be aware that the field of IC design is changing rapidly, so some of the topics covered (particularly the CAD tools) may quickly become dated. However, this is a potential problem for all texts on the subject, and is not restricted to this book. Those aware of this limitation will find this a useful addition to their library.

A true marvel of the past decade has been the way communications inventors, designers and technicians have used the building blocks of solid-state technology (see story, page 84) to develop integrated circuits which, in turn, have led to the miniaturization (see story, page 114) which has made possible the packaging of communications capabilities in compact, cost-effective devices.

It’s been called the mighty midget, the electronic wonder, a miracle of modern American technology . . . perhaps the most significant accomplishment of scientific and engineering ingenuity to date. This phenomenon is the integrated circuit or more commonly know in the electronic industry as simply the “IC”.

The integrated circuit is an enormous bundle of task-performing circuitry packed in a ridiculously small chip of mirror-like material called silicon . . . something so minute and light that it can be blown away in a moderate breeze. For size reference, an IC is about as small as a baby’s fingernial.

An IC in simplest terms is a tiny electronic device which incorporates an amazing amount of electronic functional capability.

Ten years ago we were wide-eyed to see how a single IC could do the job of thousands of transistors. An early integrated circuit was the “calculator-on-a-chip” IC made by Texas Instruments for its own electronic calculators as well as those of other makers. This IC measuring less than a quarter of an inch square contains the equivalent of over 6000 transistors, and has all the electronics necessary for computing mathematical problems.

The handheld electronics calculator was one of the first examples of how ICs were introduced into a number of newer products for the consumer, for business and industry as well as for space exploration equipment. Early on we saw IC’s revolutionizing not only calculators but also hearing aids, television sets, radios, automobiles, data-processing equipment, wristwatches, and, especially, small and large computers for industry, business, and space programs.

Invented by Jack Kilby of Texas Wnstruments in 1958, the integrated circuit belongs to the family of semiconductors that includes transistors and diodes. All are similar in size and in the way they’re fabricated. Only, as the name implies, the integrated circuit has considerably more electronics functions integrated on practically the same small area as the transistor. Basically, an IC measures and controls the flow of electrical current, and this enables integrated circuits of various types to control the performance of all kinds of electronics equipment.

What propelled the IC to such popular heights is its size, weight, and performance. Inherent economies and reliability of the IC result from the ever increasing complexity of ICs, the new technologies applied to them which have had a tremendous impact on making them more reliable and less expensive, and extensive manufacturing experience gained over the last decade.

Mass production and extensive manufacturing experience has brought the price of ICs down considerably to the point where it’s economically feasible for them to be used in a multitude of consumer products like color TV, radios, and automobiles.

The magic of the integrated circuit is in the way it’s made. It undergoes a series of chemical processes, using successive photolithographic steps similar to the process of making printing plates and then subjected to high temperature diffusions . . . everything on a tightly controlled, microscopic scale.

The integrated circuit does not require too many more manufacturing steps than an individual transistor. The difference is that individual transistors must be handled independently . . . tested, packaged, shipped, placed in circuit boards, soldered, and so forth.

Donald Procknow, vice chairman and chief operating officer of AT&T technologies, sees a continuing bright future for integrated circuits, saying: “We see the capability of integrated circuits increasing for at least another ten years, especially among microprocessors and memories. New market opportunities will be created with each advance in technology.

IBM has developed an experimental computer chip that can store more than one million bits of information. The so-called dynamic random access memory chip is the first of its kind to be developed by a United States company, although several Japanese companies claim to have developed such chips but haven’t marketed them. IBM officials say the chip was made on an existing manufacturing line, meaning that the company, if it decided to begin production, could start making the chip quickly.

A new 256K dynamic random access memory was recently introduced by Fujitsu Limited in Tokyo. It is said to be the fastest and smallest RAM produced, integrating 2.6 million bits onto a silicon chip measuring only 34.1 square microns, or 0.013299 of a square inch.

A new single-chip electronic telephone circuit, the MC34010, is a monolithic integrated circuit that is designed, using bipolar linear I.sup.2.L technology, to provide all basic telephone functions in a single IC, plus logic to interface with an external processor. The major sections of the circuit include a dual-one multi-frequency dialer (DTMF), tone ringer, speech network, a decline voltage regulator and MPU interface. The I.sup.2.L technology provides low voltages operation and high static discharge immunity. The DTMF dialer uses a frequency synthesis technique that allows use of a 500 kHz ceramic resonator. This generator uses a keyboard comprised of SPST switches in a X-Y configuration. Internal speech circuit muting eliminates the need for a common switch and it operates at a very a very low line voltage. The tone ringer from Motorola

An integrated circuit, commonly referred to as an IC, is a microscopic array of electronic circuits and components that has been diffused or implanted onto the surface of a single crystal, or chip, of semiconducting material such as silicon. It is called an integrated circuit because the components, circuits, and base material are all made together, or integrated, out of a single piece of silicon, as opposed to a discrete circuit in which the components are made separately from different materials and assembled later. ICs range in complexity from simple logic modules and amplifiers to complete microcomputers containing millions of elements.

The impact of integrated circuits on our lives has been enormous. ICs have become the principal components of almost all electronic devices. These miniature circuits have demonstrated low cost, high reliability, low power requirements, and high processing speeds compared to the vacuum tubes and transistors which preceded them. Integrated circuit microcomputers are now used as controllers in equipment such as machine tools, vehicle operating systems, and other applications where hydraulic, pneumatic, or mechanical controls were previously used. Because IC microcomputers are smaller and more versatile than previous control mechanisms, they allow the equipment to respond to a wider range of input and produce a wider range of output. They can also be reprogrammed without having to redesign the control circuitry. Integrated circuit microcomputers are so inexpensive they are even found in children's electronic toys.

The first integrated circuits were created in the late 1950s in response to a demand from the military for miniaturized electronics to be used in missile control systems. At the time, transistors and printed circuit boards were the state-of-the-art electronic technology. Although transistors made many new electronic applications possible, engineers were still unable to make a small enough package for the large number of components and circuits required in complex devices like sophisticated control systems and handheld programmable calculators. Several companies were in competition to produce a breakthrough in miniaturized electronics, and their development efforts were so close that there is some question as to which company actually produced the first IC. In fact, when the integrated circuit was finally patented in 1959, the patent was awarded jointly to two individuals working separately at two different companies.

After the invention of the IC in 1959, the number of components and circuits that could be incorporated into a single chip doubled every year for several years. The first integrated circuits contained only up to a dozen components. The process that produced these early ICs was known as small scale integration, or SSI. By the mid-1960s, medium scale integration, MSI, produced ICs with hundreds of components. This was followed by large scale integration techniques, or LSI, which produced ICs with thousands of components and made the first microcomputers possible.

The first microcomputer chip, often called a microprocessor, was developed by Intel Corporation in 1969. It went into commercial production in 1971 as the Intel 4004. Intel introduced their 8088 chip in 1979, followed by the Intel 80286, 80386, and 80486. In the late 1980s and early 1990s, the designations 286, 386, and 486 were well known to computer users as reflecting increasing levels of computing power and speed. Intel's Pentium chip is the latest in this series and reflects an even higher level.

How Integrated Circuit Components Are Formed

In an integrated circuit, electronic components such as resistors, capacitors, diodes, and transistors are formed directly onto the surface of a silicon crystal. The process of manufacturing an integrated circuit will make more sense if one first understands some of the basics of how these components are formed.

Even before the first IC was developed, it was known that common electronic components could be made from silicon. The question was how to make them, and the connecting circuits, from the same piece of silicon? The solution was to alter, or dope, the chemical composition of tiny areas on the silicon crystal surface by adding other chemicals, called dopants. Some dopants bond with the silicon to produce regions where the dopant atoms have one electron they can give up. These are called N regions. Other dopants bond with the silicon to produce regions where the dopant atoms have room to take one electron. These are called P regions. When a P region touches an N region, the boundary between them is referred to as a PN junction. This boundary is only 0.000004 inches (0.0001 cm) wide, but is crucial to the operation of integrated circuit components.

Within a PN junction, the atoms of the two regions bond in such a manner as to create a third region, called a depletion region, in which the P dopant atoms capture all the N dopant extra electrons, thus depleting them. One of the phenomena that results is that a positive voltage applied to the P region can cause an electrical current to flow through the junction into the N region, but a similar positive voltage applied to the N region will result in little or no current flowing through the junction back into the P region. This ability of a PN junction to either conduct or insulate depending on which side the voltage is applied can be used to form integrated circuit components that direct and control current flows in the same manner as diodes and transistors. A diode, for example, is simply a single PN junction. By altering the amount and types of dopants and changing the shapes and relative placements of P and N regions, integrated circuit components that emulate the functions of resistors and capacitors can be also be formed.