The Makers of the Microchip Creating the Planar Integrated Circuit, Establishing Silicon Valley Christophe Lécuyer and David C. Brock

The history of a seminal company: Fairchild Semiconductor The history of two fundamental innovations: the planar process and the integrated circuit A documentary history approach: follow the emergence of the firm and the creation of the microchip through the documents produced by the founders and other key engineers at Fairchild Semiconductor

Microchips and the digitalization of the human-built world Microchips and the “Silicon Valley dynamic” Fairchild was a critical site for establishing the developmental path of digital electronics Fairchild was important for initiating key aspects of the “Silicon Valley dynamic” The microchip and the “Silicon Valley dynamic” emerged in the context of three logics: - Silicon logic - User logic - Competitive logic Early diffused silicon transistor from Bell Labs

Fairchild Semiconductor’s establishment (October 1957) A very unusual founding team Complementary skills and competencies (chemistry, solid state physics, optics, metallurgy, electrical engineering, industrial and mechanical engineering, glass blowing…) The Fairchild Eight

Where Fairchild came from: The Shockley Semiconductor Laboratory Rebellion against William Shockley (Shockley’s management style and differences of opinion about the direction of the firm) The letter to Hayden Stone & Company Financing from Fairchild Camera and Instrument (an early form of venture capital) This prospectus is to introduce a group of seven senior scientists and engineers who have been working together in the development of transistors and other semiconductor devices…Becacuse of seemingly insuperable problems with the present management this group wishes to find a corporation interested in getting into the advanced semiconductor device business…This group of seven people, which represents a majority of the senior staff, is presently working at the Shockley Semicondcutor Laboratory…During this period much progress has been made in the field of silicon diffused devices. This has been accomplished at a cost of over a million dollars. Our present dissatisfactions have arisen primarily from Shockley’s confusing and demoralizing management.

Sputnik and the growth of the military market for silicon devices Focus on the development of manufacturing processes The order from IBM (core driver for an airborne computer) Development of two transistors: NPN (Moore) and PNP (Hoerni) Introduction of the first diffused silicon transistor to the market (August 1958); monopoly position for about a year Jay Last personal notebook, entry on 18 Nov 1957, shows tasks/schedule/who is doing it Sawing, JB; Orientation, CSR; Routine Lapping, JTL; Photoetching

Hoerni and the development of the planar process (January-March 1959) The reliability problems of Fairchild’s first transistor (the tapping test problem) Hoerni and the development of the planar process (January-March 1959) Hoerni returned to ideas he had jotted down in his notebook in December 1957: - Oxide layer - Protected junctions - Contacts He set these ideas aside for about a year Jean Hoerni’s patent notebook, page two of 1 December 1957 entry on the planar process and planar device. Note batch processing.

Hoerni made the first planar transistor in March 1959 Starting in January 1959, Hoerni worked on the planar process (for a PNP transistor, and then an NPN transistor) Hoerni made the first planar transistor in March 1959 Decision to invest significant resources in the development of the planar - Much improved reliability and performance - Hoerni’s showmanship - Autonetics and the demands of military computing (Minuteman) - Competitive pressures (Rheem Semiconductor) Planar structure and planar process

Difficult transfer to production (major yield problems) Fairchild introduced the planar transistor at the IRE show in March 1960 Fairchild’s engineers planarized the firm’s transistor line and developed new planar transistors and diodes (new plant in San Rafael) The starting point for the last 50 years of semiconductor manufacturing technology

Different approaches to miniaturization: - Hybrid circuits The planar process gave Fairchild Semiconductor a significant advantage in the development of miniaturized electronic circuits Different approaches to miniaturization: - Hybrid circuits - Thin film circuits - Functional devices - Integrated circuits (TI, Sprague) Robert Noyce used Hoerni’s invention of the planar to conceive a practical form of the integrated circuit Robert Noyce, Patent notebook entry, 23 January 1959 Methods of isolating multiple devices: In many applications now it would be desirable to make multiple devices on a single piece of silicon in order to be able to make interconnections between devices as part of the manufacturing process, and thus reduce size, weight, etc, as well as cost per active element…diffusing all the way through the wafer…metal connections are made through the holes in the oxide by evaporating metal to interconnect the diodes as desired for a particular circuit…Isolating multiple unites by including at least 1 p-n junction between them

The challenge of isolation Competition with TI and the launch of a crash program on microcircuits directed by Jay Last (Summer 1959) The challenge of isolation Last and the invention of the physically isolated integrated circuit Proof of concept for the planar integrated circuit Jay Last, Patent notebook entry, 23 Feb 1960, physical isolation. The problem exists on our micorlogic element of separating electrically collectors of various transistors making up the circuit. This can be done by diffusing in an insulating layer of the like (see patent application of Noyce) or by physically separating the devices.

The diffusion isolated integrated circuit A concept first proposed by Noyce Idea revisited and realized by Lionel Kattner and Isy Haas (September 1960) Introduction of an entire line of integrated circuits to the market in March 1961 Fairchild’s planar integrated circuits set the developmental path for semiconductor technology

Fairchild Semiconductor’s innovations in the 1960s: the development of MOS and the creation of commercial markets for silicon transistors and integrated circuits Formation of new integrated circuit firms out of Fairchild: Amelco, Signetics, General MicroElectronics (first wave, early 1960s); National, Intel, Intersil… (second wave, late 1960s and early 1970s) Emergence of the venture capital business in Silicon Valley The second wave of Fairchild spin-offs, often funded by venture capital, created the microchips that accelerated the digitalization of the human-built world