Molded Electronic Package Geometry To Control Warpage And Die Stress

Abstract

A method and system are provided for a molded electronic package geometry that enables control of warpage and die stress. A mold tool can be closed to define a space or cavity about a semiconductor die disposed on a substrate. Once the mold tool is closed, a mold material can be applied to the space to produce a mold cap. The mold cap geometry can have a first surface that is in contact with the surface of the substrate and a second surface that is opposite the first surface. The second surface can define a tapered portion of the mold cap in which the larger thickness of the tapered portion of the mold cap is in proximity to the semiconductor die and the smaller thickness of the tapered portion of the mold cap is away from the semiconductor die. The thickness of the tapered portion can vary linearly or non-linearly.

What is claimed is: 
     
         1 . A method, comprising:
 placing in a mold tool a substrate, the substrate having a surface and a semiconductor die disposed on the surface;   closing the mold tool to define a space about the semiconductor die and about the surface of the substrate; and   applying a mold material to at least a portion of the defined space to produce a mold cap having a first surface that is in contact with the surface of the substrate and a second surface that is opposite the first surface,
 wherein the second surface of the mold cap defines a tapered portion of the mold cap in which the larger thickness of the tapered portion of the mold cap is proximate to the semiconductor die and the smaller thickness of the tapered portion of the mold cap is away from the semiconductor die. 
   
     
     
         2 . The method of  claim 1 , comprising applying a flexible die seal to a surface of the semiconductor die,
 wherein the flexible die seal produces an undercut on the second surface of the mold cap adjacent to the semiconductor die, and   wherein the tapered portion of the mold cap has the larger thickness adjacent to the undercut and the smaller thickness away from the undercut.   
     
     
         3 . The method of  claim 1 , wherein the thickness of the tapered portion of the mold cap varies monotonically. 
     
     
         4 . The method of  claim 1 , wherein the thickness of the tapered portion of the mold cap varies linearly. 
     
     
         5 . The method of  claim 1 , wherein the thickness of the tapered portion of the mold cap varies non-linearly. 
     
     
         6 . The method of  claim 1 , wherein the mold material includes an epoxy molding compound. 
     
     
         7 . The method of  claim 1 , wherein the substrate includes a coreless substrate. 
     
     
         8 . The method of  claim 1 , comprising producing an electronic package including the substrate, the semiconductor disposed on the surface of the substrate, and the mold cap. 
     
     
         9 . The method of  claim 1 , comprising applying the mold material to at least a portion of the defined space through an opening in the mold tool after the mold tool is closed. 
     
     
         10 . A method for producing an electrical circuit, comprising:
 placing in a mold tool a semiconductor die;   closing the mold tool to define a space about the semiconductor die; and   applying a mold material to at least a portion of the defined space to produce a mold cap that is in contact with the semiconductor die,
 wherein the mold cap includes a tapered portion in which the larger thickness of the tapered portion of the mold cap is proximate to the semiconductor die and the smaller thickness of the tapered portion of the mold cap is away from the semiconductor die. 
   
     
     
         11 . The method of  claim 10 , comprising applying a flexible die seal to a surface of the semiconductor die,
 wherein the flexible die seal produces an undercut on a second surface of the mold cap adjacent to the semiconductor die, and   wherein the tapered portion of the mold cap has the larger thickness adjacent to the undercut and the smaller thickness away from the undercut.   
     
     
         12 . The method of  claim 10 , wherein the thickness of the tapered portion of the mold cap varies monotonically. 
     
     
         13 . The method of  claim 10 , wherein the thickness of the tapered portion of the mold cap varies linearly. 
     
     
         14 . The method of  claim 10 , wherein the thickness of the tapered portion of the mold cap varies non-linearly. 
     
     
         15 . The method of  claim 10 , wherein the mold material includes an epoxy molding compound. 
     
     
         16 . An electronic package, comprising:
 a substrate;   a semiconductor die disposed on a first portion of a surface of the substrate; and   a mold cap disposed on at least a second portion of the surface of the substrate, the second portion being different from the first portion,
 wherein the mold cap includes a tapered portion in which the larger thickness of the tapered portion is proximate to the semiconductor die and the smaller thickness of the tapered portion is away from the semiconductor die. 
   
     
     
         17 . The electronic package of  claim 16 , wherein the thickness of the tapered portion of the mold cap varies monotonically. 
     
     
         18 . The electronic package of  claim 16 , wherein the thickness of the tapered portion of the mold cap varies linearly. 
     
     
         19 . The electronic package of  claim 16 , wherein the thickness of the tapered portion of the mold cap varies non-linearly. 
     
     
         20 . The electronic package of  claim 16 , wherein the mold cap has an undercut produced by a flexible die seal and adjacent to the semiconductor die, the tapered portion of the mold cap having the larger thickness adjacent to the undercut and the smaller thickness away from the undercut.