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. [1]
There appeared to be some confusion inside DEC at the time, as various manuals refer to it as "FLIP CHIP", "Flip Chip", "FLIP-CHIP", and "Flip-Chip", with trademark and registered trademark symbols.
The modules were called Flip-Chip because early versions of some of these modules used flip chip mounting for individual diode chips, but these were eventually found to be unreliable so conventional discrete diodes replaced the flip chips. In later computers where DEC used integrated circuits, they continued to use "Flip-Chip" despite the fact that actual flip chip mounting was not used, so that they could retain their trademark. Eventually, on June 6, 1987, the trademark was allowed to expire.[1]