14 THE COFIRED CERAMIC TAPE TECHNOLOGY [1]

Much of the early work that eventually lead to the introduction of cofired ceramic technology as a viable microelectronic packaging technology took place at RCA in Somerville, NJ. A patent (3,192,086) for monolithic tape cast ceramics was issued in 1965 to W. J. Gyurk. A second patent (3,189,978) Method for Manufacturing Multilayer Circuits was issued to H. W. Stetson in the same year. Both were assigned to RCA. Basically, the patents define the cofired ceramic processes used in the manufacture of semiconductor packages both past and present. Figure 14-1 is taken from the Stetson patent.

Figure 14-1: Patent on Cofired Ceramic Manufacture Issued to Harold W. Stetson, RCA

A co-worker of Gyurk and Stetson, Bernard Schwartz, who was a major contributor to the development of the technology, left RCA to join IBM. At IBM, he was instrumental in the introduction of the cofired ceramic tape process and largely responsible for its implementation and subsequent enhancement as a premiere packaging technology. At IBM all packaging activities were directed towards supporting their microelectronic and computer programs, in particular, their mainframe computers, today s servers. The cofired technology, specifically, addressed high-performance multichip packaging, employing high-density multilayer cofired ceramic interconnect substrates and flip chip assembly.