Patent ID: 9064881
Filing Date: 2015-06-23
Classification: H01L

Abstract:
1. A device comprising: a die comprising a first surface and a second surface opposite the first surface; a work piece bonded to the die through flip-chip bonding; a first underfill on sidewalls of the die and encircling the die, wherein the first underfill covers substantially all of the sidewalls of the die, and wherein substantially none of the first underfill is directly over and contacting the first surface of the die, or under and contacting the second surface of the die; and a second underfill filling a gap between the die and the work piece, with the second underfill extending onto sidewalls of the first underfill, wherein the first underfill has a first coefficient of thermal expansion (CTE) smaller than a second CTE of the second underfill, or the first underfill has a Young's module greater than a Young's module of the second underfill.