The Z80 came about when physicist Federico Faggin left Intel at the end of 1974 to found Zilog with . At Fairchild Semiconductor, and later at Intel, Faggin had been working on fundamental transistor and semiconductor manufacturing technology. He also developed the basic design methodology used for memories and microprocessors at Intel and led the work on the Intel 4004, the 8080 and several other ICs. Masatoshi Shima, the principal logic and transistor level-designer of the 4004 and the 8080 under Faggin's supervision, joined the Zilog team.