The Intel 4004 — the world’s first microprocessor

From left, Federico Faggin, Ted Hoff, and Stanley Mazor holding Intel 4004 processors at the National Inventors Hall of Fame in 1996. PHOTO: PAUL SAKUMA/AP

Released in 1971, the Intel 4004 is arguably the first ever microprocessor. Until this time, chips were hard-wired to perform specific functionality. The 4004 was the first integrated circuit that could be programmed for a variety of tasks.

In 1968, the Japanese company Busicom approached Intel, asking them to design a set of 4 chips for an electronic calculator they were building. Whereas three of the four chips were to be standard control and RAM circuits, Busicom wanted the CPU to be general purpose. One of their engineers, Masatoshi Shima, had the brilliant idea of encoding an instruction set that could be programmed. Intel accepted the contract and assigned Marcian Hoff and later Stanley Mazor to work with Shima on the design.

4004 pinout diagram — Wikipedia

Progress was fast until it came time to lay down the circuit in silicon and fabricate it. None of the team members had experience with such a complex silicon layout. Intel turned to Federico Faggin and lured him from Fairchild Semiconductor. Faggin’s genius lay in his pioneering work on SGT (Silicon Gate Technology.)

Until this point, chips were fabricated using aluminum gate MOS technology. The transistors…