WARPAGE-REDUCING PACKAGING DESIGN

摘要

A flange and packaging assembly (100) characterized by a structural lip (200) configured to impart resistance to thermal-induced deformation (i.e. "stiffness") to the flange during elevated temperature die attachment processes. The stiffness is achieved through appropriate configuration of the lip (height, width and shape) and is sufficient to at least partially counteract the stresses generated from coefficient of thermal expansion differentials between the flange and a die (400) attached to it. The lip may be molded or otherwise formed with the flange as a unitary lip-stiffened flange, or may be a separate structure that is affixed to the flange. The flange has a lip-stiffened region for die attachment. This region may be raised above the first surface of the substrate base for enhanced stiffening, and may be in the form of a single pedestal (300) supporting a single or multiple die, or may be a series of raised pedestals (330), each supporting one or more die. The leads (500) may be embedded in a polymetric material that is attached to the flange that is of sufficient thickess to provide the required stiffness. The embedded leads may be shaped and formed so that the desired seating plane height is achieved. The lead form placement can be either on the interior or exterior of the embedded polymetric material. The polymetric material can be supported along the edge of the flange or be seated on a part of an extrusion from the flange.