The Chip—Today’s Electronic Building Block
THE digital coffee machine that perks your morning brew, the pocket calculator that saves you a lot of pencil pushing, the multicolored displays on the dashboards of new automobiles—all of these have one thing in common: They have been made possible by the use of waferlike silicon chips not much larger than a baby’s thumbnail.
These chips are also found in many other things you may own—watches, TVs, radios, telephones, appliances, and some tools. From the common everyday things used in the home to top-secret military applications, this tiny gem of an electronic marvel plays a major role in transforming the way people around the world live and work. But just what is a silicon chip? How did it come about? And how has it found its way into your everyday life?
What Is a Chip?
A silicon chip is basically a collection of miniature electronic circuits. You might compare an electronic circuit to a sentence in this article. Every sentence is made up of standard components like nouns, verbs, and adjectives. By arranging these components in different ways, sentences may be put together as statements, questions, even poetry. And by combining sentences in a logical manner, we have conversation and writing.
Electronic circuits are very similar. By arranging standard electronic components—transistors, diodes, resistors, and the like—in different ways, electronic circuits that perform many functions can be developed. Then, thousands of these circuits can be combined to perform all sorts of useful electronic processes. This is so, at least in theory.
In practice, however, it is an enormous task to connect hundreds of thousands of electronic components, not to mention the space they take up. That was precisely the obstacle that faced scientists back in the late 1940’s as they assembled the first generation of computers. One such computer in Philadelphia, known as ENIAC (Electronic Numerical Integrator and Calculator), occupied 1,500 square feet [140 sq m] of floor space, weighed about 30 tons [27,000 kg], and contained about 19,000 vacuum tubes! This monster required as much energy to operate as 1,300 100-watt light bulbs. Its appetite for electricity gave rise to amusing stories. One claimed that when it was turned on, all the lights in West Philadelphia would dim.
For all their bulk, the capability of ENIAC and its peers was absolutely puny compared with that of the present generation of computers. While a desktop computer today can perform millions of operations a second, ENIAC trudged along at about 5,000 additions or just 300 multiplications per second. And while computers today, costing only a few hundred dollars, may have enough internal memory to store 100,000 numbers or more, EDVAC, another early giant, could store only 1,024. What happened to make today’s computers so much more powerful?
In the early 1960’s, the small and efficient transistor came on the scene. Finally, computer scientists were able to bring their slow, power-hungry monsters down to size. Still, another advance was to take place before today’s computers could be built. This was to come from the world of photography.
Miniaturization and the Chip
As you may know, by using the right equipment, photographs can be enlarged or reduced to suit one’s needs. In recent years, a technique has been developed that allows computer engineers to reduce photographically large blueprints of computer circuits to a tiny size. These blueprints may be as complex as the street plan of a major city, but when reduced in size they will fit on a chip smaller than a contact lens. The photos are not made on ordinary photographic paper but on wafers of pure silicon, one of the most abundant elements on earth, found in ordinary sand.
Certain properties of silicon make it the preferred choice in chip making. For instance, by adding various types of chemical impurities to it, silicon can be made to behave like resistors, capacitors, and even transistors. So by doping specific areas of a single silicon chip with these impurities, it is possible to reproduce an entire electronic circuit on it.
From melted and purified sand, crystals of silicon are grown until they resemble long tubes of salami. Then they are sliced into thin wafers and specially coated. Tiny images of the large electronic circuits are etched on the wafers in successive layers. Chemical impurities are added at appropriate spots. And what ends up on the chips are not just pictures but actual functioning electronic circuits, called integrated circuits, or ICs for short.
Integrated circuits made in the 1960’s contained about a hundred electronic components. This enabled engineers to build suitcase-size “small” computers for laboratories and other institutions. By the late 1970’s, LSI (large-scale-integration) chips with over a hundred thousand components were made. These chips are so complex that just one of them could theoretically perform the functions of a complete computer, such as operating a microwave oven or running a car. Today, computer scientists are talking about VLSI (very large-scale-integration) chips that contain millions of components. Imagine crowding the street plans of a city nearly 1,000 miles [1,600 km] square, or twice the size of Alaska, onto a chip a quarter inch [0.6 cm] square!
The Chip and You
Use of the chip eliminates much of the tedious soldering and hand labor that would be required in the manufacturing of complex electronic devices. This makes the end product less expensive, more reliable, and smaller. Mass production has so drastically reduced the cost of chips with special talents, such as sound synthesis, that they are used in all sorts of products today.
Thus we find these chips used in talking games, vending machines, and automobiles all around us. In some countries the telephone “operator” who tells you the time or gives you a phone number may be made of silicon! Consumer products that use chips to understand your spoken commands are also becoming popular. Some of these may just be gimmicks, but others could provide much-needed assistance to handicapped persons.
Chips have also been harnessed in the industrial and business realm. In factories, they are used to control robots that can replace humans in boring, repetitive, or dangerous jobs. They are already making major inroads in automobile manufacturing, doing jobs like welding and painting. In offices, typewriters are rapidly being replaced with electronic word processors that check your spelling, allow you to make changes without retyping the entire document, and even print mailing labels automatically. This, however, is sometimes a mixed blessing. White-collar workers may have been freed from the drudgery of their office routine, but they are increasingly glued to the computer screen instead.
On the other hand, silicon chips have notably contributed to the revolution in communications technology that this generation has seen. The magazine you are reading was written on computer screens, typeset by computer, and printed with computer assistance. Indeed, through its unique MEPS system (Multilanguage Electronic Phototypesetting System) for computer-assisted typesetting and printing, the Watchtower Society is pioneering this multilanguage application of the increasingly common, valuable, and useful electronic building block—the silicon chip.