Skyworks Solutions, Inc.
CONTROL OF UNDER-FILL USING AN ENCAPSULANT AND A TRENCH OR DAM FOR A DUAL-SIDED BALL GRID ARRAY PACKAGE

Abstract:

Disclosed herein are methods of fabricating a packaged radio-frequency (RF) device. The disclosed methods use an encapsulant on solder balls in combination with a dam or a trench to control the distribution of an under-fill material between one or more components and a packaging substrate. The encapsulant can be used in the ball attach process. The fluxing agent leaves behind a material that encapsulates the base of each solder ball. The encapsulant reduces the tendency of the under-fill material to wick around the solder balls by capillary action which can prevent or limit the capillary under-fill material from flowing onto or contacting other components. The dam or trench aids in retaining the under-fill material within a keep out zone to prevent or limit the under-fill material from contacting other components.