Heat sink with elevated heat spreader lid

Abstract

Provided is a heat sink designed to constrain warpage during thermal cycling. The heat sink is composed of a picture frame stiffener and a heat spreader lid. The stiffener has a thickness greater than that of the height of a die bonded on a substrate in the package which the heat sink is or is to be used. The increased thickness of the stiffener beyond conventional designs serves to increase its stiffness and thereby enhance its capacity to constrain the substrate to prevent its warpage during thermal cycling. The thickened stiffener is coupled with an elevated heat spreader lid, that is, a heat spreader lid with a elevated central portion configured for engagement with the picture frame stiffener such that a central portion of at least one side of the heat spreader lid extends into the opening in the picture frame stiffener. As a result, the heat spreader lid is in a position to constrain warpage of the package by applying a counter force against a warping die.

Dependencies are inferred from the claim text.