The Computer on a Chip

The invention of the light bulb in 1879 symbolized the beginning of electronics. Electronics then evolved into the use of vacuum tubes, then transistors, and now integrated circuits. Today's microminiaturization of electronic circuitry is continuing to have a profound effect on the way we live and work.Current technology permits the placement of hundreds of thousands of transistors and electronic switches on a single chip. Chips already fit into wristwatches and credit cards, but electrical and computer engineers want them even smaller. In electronics, smaller is better. The ENIAC, the first full-scale digital electronic computer, weighed 50 tons and occupied an entire room. Today, a computer far more powerful than the ENIAC can be fabricated within a single piece of silicon the size of a child's fingernail.Chip designers think in terms of nanoseconds (one billionth of a second) and microns (one ionth of a meter). They want to pack as many circuit elements as they can into the structure of a chip. High-density packing reduces the time required for an electrical signal to travel from one circuit element to the next—resulting in faster computers. Circuit lines on the initial Intel processors (early 1980s) were 6.5 microns wide. Today's are less than .5 microns. The latter holds 35 million transistors and is 550 times as powerful as the initial one. By the turn of the century, researchers expect to break the .2 micro barrier.Chips are designed and manufactured to perform a particular function. One chip might be a microprocessor for a personal computer. Another might be for primary storage or the logic for a talking vending machine. Cellular telephones use semiconductor memory chips.The development of integrated circuits starts with a project review team made up of representatives from design, anufacturing, and marketing. This group works together to design a product the customer needs. Next, team members go through prototype wafer manufacturing to resolve potential manufacturing problems. Once a working prototype is produced, chips are manufactured in quantity and sent to computer, peripheral, telecommunications, and other customers The manufacturing of integrated circuits involves a multistep process using various photochemical etching and metallurgical techniques. This complex and interesting process is illustrated here with photos, from silicon to the finished product. The process is presented in five steps: design, fabrication, packaging, testing, and installation.