Techniques for molded underfill for integrated circuit dies

Abstract

Techniques for providing a unified underfill and encapsulation for integrated circuit die assemblies. These techniques include a molding technique that includes dipping a die assembly including a substrate and one or more dies into a chamber having molding material, sealing the chamber, and lowering pressure in the chamber to coax the molding material into space between the die(s) and substrate. The use of this molding technique, as contrasted with a capillary underfill technique in which underfill material is laid down adjacent dies and fills space under the die via capillary action, provides several benefits. One benefit is that the molding material can include a higher silica particle filler content (% by weight) than the material for the capillary underfill technique, which improves CTE. Another benefit is that various design constraints related to, for example, warpage and partial underfill are eliminated or improved.