Varied-thickness heat sink for integrated circuit (IC) package

Abstract

An inventive integrated circuit package includes a package body, such as a transfer molded plastic or preformed ceramic package body, having an integrated circuit die positioned therein. A lead frame, such as a peripheral lead, Leads-Over-Chip (LOC), or Leads-Under-Chip (LUC) lead frame, includes a plurality of leads with portions enclosed within the package body that electrically connect to the integrated circuit die. A heat sink is positioned at least partially within the package body so a surface of a first portion of the heat sink faces the lead frame in close proximity to a substantial part, such as at least eighty percent, of the area of the enclosed portion of the lead frame to thereby substantially reduce an inductance associated with each of the leads.

1 . An integrated circuit (IC) package comprising: 
 a package body;    an IC die positioned within the package body;    a lead frame including a plurality of leads having portions enclosed within the package body that connect to the IC die; and    an electrically conductive heat sink positioned at least partially within the package body with a surface of a first portion of the heat sink facing the lead frame in close proximity to a substantial part of the enclosed portion of each of the leads of the lead frame and with a die-attach area on the surface of the first portion attached to the IC die, a second portion of the heat sink projecting away from the first portion under the die-attach area and the IC die.    
   
   
       2 . The integrated circuit package of  claim 1 , wherein the heat sink is electrically isolated from the lead frame.  
   
   
       3 . A heat sink for an integrated circuit (IC) package having a lead frame including a plurality of leads having portions enclosed within the IC package that connect to an IC die, the heat sink comprising: 
 a first portion having a surface constructed to face the lead frame in close proximity to a substantial part of the enclosed portion of each of the plurality of leads of the lead frame, a die-attach area on the surface of the first portion being attachable to the IC die; and    a second portion substantially opposite the die-attach area for projecting away from the first portion under the die-attach area and the IC die.    
   
   
       4 . A lead frame assembly comprising: 
 a lead frame; and    a heat sink positioned with a surface thereof in a substantially mutually parallel and co-extensive relationship with, and in close but electrically insulated proximity to, the lead frame.    
   
   
       5 . The integrated circuit package of  claim 4 , wherein the heat sink is electrically isolated from the lead frame.  
   
   
       6 . An integrated circuit (IC) package comprising: 
 a package body;    an IC die positioned within the package body;    a lead frame including a plurality of leads having portions enclosed within the package body that connect to the IC die; and    an electrically conductive heat sink positioned at least partially within the package body with a surface of a first portion of the heat sink facing the lead frame in close proximity to a substantial part of the enclosed portion of each of the leads of the lead frame and with a die-attach area on the surface of the first portion attached to the IC die, a second portion of the heat sink projecting away from the first portion under the die-attach area and the IC die, the heat sink being electrically isolated from the lead frame.