As the world's largest semiconductor company, the Intel Corporation invented the technology-in 1968-that put computer memory on tiny silicon chips rather than in magnetic fields. Interactive exhibits here in the company headquarters walk visitors through the principles of transistor technology, from identification of conductors to chip design and production. The use of these chips in personal computers, through the current Pentium IV processor, and future practical applications is also examined.To make a silicon chip, sand is chemically purified, converted into crystal ingots, melted with added trace chemicals and cooled, then ground to a uniform diameter and sliced into grooved wafers. A photolithographic etching process forms the multi-layered transistors on a chip; aluminum is patterned on the wafer to make electrical connections that complete the transistor. Remarkably, a microprocessor today contains 50-100 million transistors, and circuitry lines are 1/500th the width of a human hair.