  Bump bonding is a superior assembly alternative compared to conventional wire
bond techniques. It offers a highly reliable connection with greatly reduced
parasitic properties. The Flip Chip on Board (FCOB) procedure is an especially
attractive packaging method for applications requiring a large number of
connections at moderate pitch. This paper reports on the successful
demonstration of FCOB assembly based on solder bumps down to 250um pitch using
a SUESS MA8 flip chip bonder at Fermilab. The assembly procedure will be
described, microscopic cross sections of the connections are shown, and first
measurements on the contact resistance are presented.
