Fairchild’s Approach: The Planar Process

First experimental planar IC

The first working experimental planar IC, built in May 1960, used an isolation technique proposed by Jay Last: deep channels were etched from the rear of the silicon wafer and filled with non-conducting epoxy.

Fairchild’s Approach: The Planar Process

The next step in IC evolution after Kilby’s “flying wire” circuits came at Fairchild Semiconductor in 1959.

Jean Hoerni’s “planar” process improved transistor reliability by creating a flat surface structure protected with an insulating silicon dioxide layer. Robert Noyce then proposed interconnecting transistors on the wafer by depositing aluminum “wires” on top. Following Noyce’s lead, Jay Last’s team built the first planar IC in 1960, spawning the modern computer chip industry.

Kilby and Noyce are considered co-inventors of the IC. Kilby alone received the 2000 Nobel Prize because Noyce had died in 1990.

Planar process patent

These figures are from Jean Hoerni’s planar process patent, “Method of manufacturing semiconductor devices” (U.S. Patent # 3.025,589) filed in May 1959.

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Silicon Wafer, Fairchild, 1958

This is a typical 1-inch diameter wafer from 1959, when Jean Hoerni developed the planar manufacturing process.

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CDC 6600 module with 2N709 transistor, circa 1964

This uses the first silicon transistor faster than those made from germanium. Hoerni developed the 2N709 specifically for the CDC 6600 supercomputer.

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Planar IC patent

These figures are from Robert Noyce’s planar IC patent, "Semiconductor device-and-lead structure" (U. S. Patent # 2981877) filed in July 1959.

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Micrologic Type “F” flip-flop IC, 1961

Introduced in March 1961, the early Micrologic type “F” flip-flop had a die that was etched to fit into a small, round package.

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Planar process brochure

This is the front cover of a Fairchild brochure promoting the features and benefits of the planar process to the engineering community.

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Planar Transistor-Type 2N1613 (Sealed Package), Fairchild, 1960

To solve problems with Fairchild’s transistors for the Minuteman I missile computer, physicist Jean Hoerni developed the planar process. His solution saved the company and changed the industry.

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Fairchild co-founders in discussion

Robert Noyce (right) talks with his fellow co-founders in Fairchild Semiconductor’s Mountain View test area. From left: Victor Grinich Gordon Moore, Julius Blank, Eugene Kleiner, Jay Last. Jean Hoerni and Sheldon Roberts.

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The first planar IC, 1960

Jay Last’s team developed a flip-flop circuit using the new planar process. Integrating four transistors and six resistors on one chip posed many new engineering challenges. Their first prototype worked in May 1960.

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First production planar IC, 1960

This first production version of the Micrologic “F” element flip-flop planar IC was made by Isy Haas and Lionel Kattner in September 1960.

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Fabrication of the first planar integrated circuit