Browse Prior Art Database

REWORKABLE ENCAPSULANT-FREE FLIP CHIP ASSEMBLY

IP.com Disclosure Number: IPCOM000008982D
Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2002-Jul-29

Publishing Venue

Motorola

Related People

Authors:
Gregory Dunn Daniel Gamota

Abstract

Current flip chip assemblies require encapsulant material for enhanced reliability performance. Encapsulant is used to couple the die mechanically to the substrate to constrain the board during ther- mal excursions and to reduce the stress transferred to the solder joints. Underfilling the die with encap- sulant requires additional equipment such as dis- pensing robots and curing ovens. In addition, typical encapsulant materials absorb approximately 0.6 wt% moisture which affects adhesion properties and can lead to "popcorn" type failures when a flip chip ball grid array package is attached to the mother board. Finally, the use of encapsulant precludes easy removal of the die (rework).