Packaging techniques and configurations

Abstract

One embodiment of the present disclosure provides an apparatus comprising a flex circuit substrate having a core, a first solder mask and first traces disposed on the core on a first side of the flex circuit substrate, and a second solder mask and second traces disposed on the core on a second side of the flex circuit substrate. The first side is opposite to the second side. The apparatus further includes vias formed through the core to electrically couple the first traces to the second traces, and a stiffening structure coupled to the first side of the flex circuit substrate to increase structural rigidity of the flex circuit substrate. The stiffening structure provides structural support to allow attachment of an integrated circuit die to the first side of the flex circuit substrate.

What is claimed is: 
     
         1 . A method comprising:
 providing a flex circuit substrate comprising non-metal areas formed on a first side of the flex circuit substrate;   forming metal portions on a second side of the flex circuit substrate,   wherein the second side of the flex circuit substrate is located opposite to the first side of the flex circuit substrate, and   wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate.   
     
     
         2 . The method of  claim 1 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate are orthogonal to the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         3 . The method of  claim 1 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate are parallel to the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         4 . The method of  claim 3 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate substantially match a size of the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         5 . The method of  claim 3 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate substantially match a shape of the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         6 . The method of  claim 3 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate are located between the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         7 . The method of  claim 1 , further comprising:
 attaching an integrated circuit die to the first side of the flex circuit substrate; and   providing a mold compound to substantially cover (i) the integrated circuit die and (ii) at least a portion of the first side of the flex circuit substrate.   
     
     
         8 . The method of  claim 1 , wherein forming the metal portions on the second side of the flex circuit substrate comprises:
 selectively removing portions of a blanket metal layer on the second side of the flex circuit substrate to form traces on the second side of the flex circuit substrate.   
     
     
         9 . The method of  claim 8 , wherein selectively removing portions of the blanket metal layer on the second side of the flex circuit substrate to form traces on the second side of the flex circuit substrate comprises:
 depositing a photoresist material on the blanket metal layer;   exposing the photoresist material to light energy in order to define a pattern for the traces; and   selectively removing the portions of the blanket metal layer comprises etching the pattern to form the traces.   
     
     
         10 . The method of  claim 8 , wherein selectively removing portions of the blanket metal layer on the second side of the flex circuit substrate to form traces on the second side of the flex circuit substrate comprises:
 depositing a hardmask material on the blanket metal layer, wherein the hardmask material defines a pattern for the traces; and   etching the pattern to form the traces.   
     
     
         11 . The method of  claim 1 , further comprising:
 attaching an integrated circuit die to the first side of the flex circuit substrate; and   forming a stiffening structure on the second side of the flex circuit substrate under the integrated circuit to increase structural rigidity of the flex circuit substrate.   
     
     
         12 . The method of  claim 11 , wherein forming the stiffening structure on the first side comprises:
 depositing a metal layer on the second side of the flex circuit substrate.   
     
     
         13 . The method of  claim 10 , wherein forming the stiffening structure on the first side comprises:
 attaching the stiffening structure to the second side of the flex circuit substrate.   
     
     
         14 . An apparatus comprising a flex circuit substrate, wherein the flex circuit substrate comprises:
 non-metal areas formed on a first side of the flex circuit substrate; and   metal portions formed on a second side of the flex circuit substrate,   wherein the second side of the flex circuit substrate is located opposite to the first side of the flex circuit substrate, and   wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate.   
     
     
         15 . The apparatus of  claim 14 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate are orthogonal to the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         16 . The apparatus of  claim 14 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate are parallel to the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         17 . The apparatus of  claim 16 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate substantially match at least one of a size and/or a shape of the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         18 . The apparatus of  claim 16 , wherein the metal portions are formed on the second side of the flex circuit substrate to complement the non-metal areas formed on the first side of the flex circuit substrate such that the metal portions formed on the second side of the flex circuit substrate are located between the non-metal areas formed on the first side of the flex circuit substrate. 
     
     
         19 . The apparatus of  claim 14 , further comprising:
 an integrated circuit die attached to the first side of the flex circuit substrate; and   a stiffening structure formed on the second side of the flex circuit substrate under the integrated circuit to increase structural rigidity of the flex circuit substrate.   
     
     
         20 . The apparatus of  claim 19 , further comprising:
 a mold compound substantially covering (i) the integrated circuit die and (ii) at least a portion of the first side of the flex circuit substrate.