Demonstration of fine pitch FCOB (Flip Chip on Board) assembly based on solder bumps at Fermilab

摘要

Bump bonding is a superior assembly alternative compared to conventional wirebond techniques. It offers a highly reliable connection with greatly reducedparasitic properties. The Flip Chip on Board (FCOB) procedure is an especiallyattractive packaging method for applications requiring a large number ofconnections at moderate pitch. This paper reports on the successfuldemonstration of FCOB assembly based on solder bumps down to 250um pitch usinga SUESS MA8 flip chip bonder at Fermilab. The assembly procedure will bedescribed, microscopic cross sections of the connections are shown, and firstmeasurements on the contact resistance are presented.