Patent ID: 7253510

Claim:
An integrated circuit package construction for an underhung flip chip, comprising: a laminated circuit assembly having an underlying circuit layer having a connection side adapted for face to face operative connection of an underhung integrated circuit chip, the laminated circuit assembly further having an insulating layer and a downwardly facing outer conductive layer over the insulating layer and below the connection side, an underhung integrated circuit chip disposed in a window in the outer conductive layer and a plurality of solder balls of a first diameter connecting the chip to the connection side of the underlying circuit layer, said underhung integrated circuit chip have a lower side facing a separate bottom substrate; at least one region of the overlying conductive layer defined as a raised conductive pad, the pad being raised above said connection surface a substantial height and having a plurality of vertical conductive walls spaced apart from conductive material not intended to be connected; a BGA solder ball having a second diameter greater on the average than the first diameter, one side of the BGA solder ball being adhered to the raised face and another side of the BGA solder ball being adhered to a conductive portion of the bottom substrate, the diameter of the BGA solder ball alone being such that it is insufficient alone to define a clearance between the lower side of the underhung integrated circuit chip and the bottom substrate absent the height of the raised pad, the height of the raised pad combined with the diameter of the BGA solder ball as disposed on the raised pad being sufficient to define a clearance between the lower side of the underhung integrated circuit chip and the bottom substrate.