Flip Chip (PDP module)
Flip-Chip modules were used in the DEC PDP-7 (referred to in documentation as the "FLIP CHIP"), PDP-8, PDP-9 and PDP-10, beginning on August 24, 1964. The trademark "Flip-Chip"' was filed on August 27, 1964.  Various manuals produced by DEC refer to the modules as "FLIP CHIP", "FLIP-CHIP", "Flip Chip", and "Flip-Chip", with trademark and registered trademark symbols.
The first flip-chip modules mated with single-sided 18-contact card edge connectors with contacts on 1/8 inch centers. Circuit boards were 2 7/16 inches wide by 5 inches long, with a handle adding 1/2 inch. Double modules with two connectors end to end were 5 3/16 wide. Later, when two-sided boards were introduced, compatible double-sided 36-contact edge connectors were used, but the basic board dimensions were unchanged.
The modules were called Flip-Chips because early versions of some of these modules, for example, the R107 module shown, used hybrid integrated circuits built using flip chip mounting of individual diode chips on a ceramic substrate. Some boards containing flip chip modules were etched and drilled to allow those modules to be replaced by discrete components. At some points during production, conventional discrete components may have replaced these flip-chip devices, but the early use of hybrid integrated circuits allowed DEC to market the PDP-8 as an integrated circuit computer.
When DEC began to use monolithic integrated circuits, they continued to refer to their circuit boards as "Flip-Chip" modules, despite the fact that actual flip chip mounting was not used. DEC continued to hold the flip chip trademark until June 6, 1987, when the trademark was allowed to expire.
- "Flip Chip latest status". Retrieved 2010-05-28.
- The Digital Logic Handbook, 1966-67 edition. Maynard, Massachusetts: Digital Equipment Corporation. 1966.
- The Digital Logic Handbook, 1968 edition (PDF). Maynard, Massachusetts: Digital Equipment Corporation. 1968. p. 27.
- See, for example, the S111, component side, solder side.
- Digital Equipment Corporation, advertisement, Computers and Automation April 1965; pages 6-7.