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Method for making a semiconductor package with the distance between a lead frame die pad and heat spreader determined by the thickness of an intermediary insulating sheet

  • US 5,139,973 A
  • Filed: 12/17/1990
  • Issued: 08/18/1992
  • Est. Priority Date: 12/17/1990
  • Status: Expired due to Term
First Claim
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1. A method for making a semiconductor device package comprising in the following order:

  • a) bonding a back face of a semiconductor device die to a front oriented side of the die attach pad of a patterned sheet metal lead frame;

    b) connecting, via wires, the terminals on the front face of said die to the front oriented side of distal end portions of the lead fingers of said lead frame, the back sides of said distal finger end portions and the back side of said die attach pad lying in one plane to form a lead frame die sub-assembly;

    c) forming a stack comprising (1) said lead frame die sub-assembly;

    (2) a uniformly thick electrically insulating sheet of a fully cured polymeric material having a central opening of greater dimensions than those of said die attach pad, said sheet abutting the back oriented side of said lead frame with said central opening registered with said die attach pad; and

    (3) a heat spreader comprised of a metal block, said distal finger end portions being separated from said heat spreader block in said stack by an intervening portion of said insulating sheet, the space between said die attach pad and said heat spreader block being determined by the thickness of said insulating sheet; and

    d) bonding said dielectric sheet to the front side of said heat spreader and to the back sides of said distal finger end portions.

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