Exposed pad integrated circuit package

Abstract

An IC assembly including an exposed pad integrated circuit (“IC”) package having a thermal pad with a top surface and a bottom surface and with at least one peripheral surface portion extending transversely of and continuous with the bottom surface. The bottom surface and the at least one peripheral surface are exposed through a layer of mold compound. Also, methods of making an exposed pad integrated circuit (“IC”) package assembly. One method includes optically inspecting a solder bond bonding a thermal pad of an exposed pad IC package to a printed circuit board. Another method includes wave soldering an exposed pad of an IC package to a printed circuit board.

What is claimed is: 
     
         1 . An integrated circuit (“IC”) package, comprising:
 a thermal pad having a top surface and a bottom surface opposite the top surface; 
 a flange extending transversely of and continuous with the thermal pad, the flange having a surface continuous with the bottom surface of the thermal pad; and 
 a mold compound through which the bottom surface of the thermal pad and the surface of the flange are exposed, wherein:
 the bottom surface of the thermal pad is flush with a bottom surface of the mold compound; and 
 the surface of the flange is flush with a side surface of the mold compound. 
 
 
     
     
         2 . The IC package of  claim 1 , wherein the surface of the flange is substantially perpendicular to the bottom surface. 
     
     
         3 . The IC package of  claim 1 , wherein the surface of the flange is connected to the bottom surface by an arcuate surface portion. 
     
     
         4 . The IC package of  claim 1 , further comprising:
 a plurality of leads extending laterally outwardly of first and second lateral side edges of the thermal pad.   
     
     
         5 . The IC package of  claim 4 , further comprising:
 a die attached to the top surface of the thermal pad, the die having electrical contacts connected to the plurality of leads.   
     
     
         6 . The IC package of  claim 1 , wherein the flange extends a portion of a full width of the thermal pad. 
     
     
         7 . The IC package of  claim 6 , further comprising:
 a first tie bar projected past the surface of the flange; and   a second tie bar projected past the surface of the flange, wherein the flange is positioned between the first tie bar and the second tie bar.   
     
     
         8 . The IC package of  claim 7 , wherein the first and second tie bars are integrally formed with and extended along lateral sides of the thermal pad. 
     
     
         9 . The IC package of  claim 1 , wherein the flange extends a full width of the thermal pad. 
     
     
         10 . The IC package of  claim 9 , further comprising:
 a tie bar projected past the surface of the flange, the tie bar integrally formed on a top edge of the flange.   
     
     
         11 . The IC package of  claim 10 , wherein the tie bar is positioned at a center portion of the top edge of the flange. 
     
     
         12 . The IC package of  claim 1 , wherein the flange is a first flange, the IC package further comprising:
 a second flange extending transversely of and continuous with the thermal pad, wherein the second flange has a second surface continuous with the bottom surface of the thermal pad, the second surface being exposed through the mold compound and flush with a second side surface of the mold compound opposite the side surface.   
     
     
         13 . An integrated circuit (“IC”) assembly, comprising:
 an IC package including:
 a thermal pad having a thermal pad surface exposed through and coplanar with a bottom surface of a mold compound of the IC package; and 
 a flange extending transversely of and continuous with the thermal pad, the flange having a flange surface that is continuous with the thermal pad surface, and is exposed through and coplanar with a side surface of the mold compound; 
 
 a substrate including a metal pad on a top surface of the substrate; and 
 a solder layer bonding the thermal pad surface and a portion of the flange surface to the metal pad of the substrate. 
 
     
     
         14 . The IC assembly of  claim 13 , wherein the solder layer includes a solder fillet corresponding to a solder of the solder layer wicked up to the portion of the flange surface. 
     
     
         15 . The IC assembly of  claim 14 , wherein the solder fillet is visible from an external viewpoint of the IC assembly. 
     
     
         16 . The IC assembly of  claim 13 , wherein the metal pad of the substrate has a length and a width corresponding to the thermal pad. 
     
     
         17 . The IC assembly of  claim 13 , wherein the substrate includes a printed circuit board. 
     
     
         18 . The IC assembly of  claim 13 , wherein the solder layer is applied by wave solder or is a layer of reflowed solder. 
     
     
         19 . The IC assembly of  claim 13 , further comprising:
 a plurality of leads of the IC package extending laterally outwardly of first and second lateral side edges of the thermal pad, wherein the plurality of leads includes outer terminal end portions having generally flat bottom surfaces.   
     
     
         20 . The IC assembly of  claim 19 , further comprising:
 a die attached to a die-attach surface of the thermal pad opposite the thermal pad surface, the die having electrical contacts connected to the plurality of leads.