System and method for manufacturing a fabricated carrier

Abstract

A method and apparatus for fabricating a carrier having a top surface and a bottom surface, the method comprising combining a conductive portion at the top surface and a dielectric at the bottom surface, wherein the dielectric includes contact island cavities, filling one or more of the contact island cavities with solder metal to form solder islands, selectively metal plating the conductive portion, selectively etching a portion of the conductive portion, and applying solder resist to the selectively plated and etched top surface of said conductive portion.

We claim: 
     
         1 . A method of fabricating a carrier having a top surface and a bottom surface, the method comprising:
 combining a conductive portion at the top surface and a dielectric at the bottom surface, said dielectric including contact island cavities;   filling one or more of the contact island cavities with solder metal to form solder islands;   selectively metal plating the conductive portion;   selectively etching a portion of said conductive portion; and   applying solder resist to the selectively plated and etched top surface of said conductive portion.   
     
     
         2 . The method of  claim 1 , further including metalizing at least a portion of a surface of the dielectric portion that includes the contact island cavities prior to filling the contact island cavities with solder metal. 
     
     
         3 . The method of  claim 2 , wherein said metalizing comprises one of either sputtering a metal seed layer onto the dielectric portion or immersing the dielectric portion in a molten metal. 
     
     
         4 . The method of  claim 3 , wherein said metal seed layer comprises one of chromium or titanium. 
     
     
         5 . The method of  claim 2 , wherein said molten metal comprises copper. 
     
     
         6 . The method of  claim 2 , further comprising electrolytic plating the metalized portion of the surface of the dielectric portion to a predetermined thickness. 
     
     
         7 . The method of  claim 1 , wherein the solder metal comprises one of either SnAg, SnAgCu or SnCu. 
     
     
         8 . The method of  claim 1 , wherein filling one or more of the contact island cavities with solder metal comprises stencil printing solder paste onto the dielectric portion at the bottom surface and then reflowing the dielectric portion with the solder paste. 
     
     
         9 . The method of  claim 8 , wherein the solder islands are flattened by one of either pressurized rolling or coining. 
     
     
         10 . The method of  claim 1 , wherein selective plating comprises depositing metal on the conductive portion, applying a photo-imageable plating resist to the deposited metal, exposing the top surface to a predetermined image shape and/or pattern, developing the plating resist, and stripping away the plating resist. 
     
     
         11 . The method of  claim 10 , wherein the deposited metal comprises one of either Ag, Ni/Au or Pd. 
     
     
         12 . The method of  claim 1 , wherein selectively etching a portion of said conductive portion comprises etching away portions of the conductive portion that have not been selectively plated, thereby exposing portions of dielectric portion at the top surface. 
     
     
         13 . The method of  claim 12 , wherein selectively etching a portion of said conductive portion comprises applying photo imageable etching resist to the top surface, exposing a predetermined image pattern, developing the etching resist, and stripping away the etching resist. 
     
     
         14 . The method of  claim 1 , wherein the dielectric portion is fabricated by inserting dielectric material into a mold cavity, molding the dielectric material into a predetermined thickness and shape by adjusting the mold cavity size and shape. 
     
     
         15 . The method of  claim 14 , wherein the predetermined thickness is approximately  0 . 1 mm and the shape is one of either a panel, a strip or a wafer 
     
     
         16 . The method of  claim 15 , wherein the contact island cavities are conical with openings at the top surface that are smaller than openings at bottom surface. 
     
     
         17 . The method of  claim 1 , wherein filling one or more of the contact island cavities with solder metal comprises applying high temperature resistant tape to the dielectric portion at the top surface, stencil printing solder paste onto the dielectric portion at the bottom surface, removing the tape, reflowing the dielectric portion with the solder paste, and flattening the reflowed solder paste by one of either rolling or coining. 
     
     
         18 . The method of  claim 17 , wherein selective plating comprises applying a plating resist to the dielectric portion at the bottom surface, electrolytic plating the dielectric portion at the top surface to a predetermined thickness, and removing the plating resist. 
     
     
         19 . The method of  claim 18 , wherein the predetermined thickness is less than at least 8 um or 5 um. 
     
     
         20 . The method of  claim 14 , wherein the dielectric material is a polymerized molding compound based on a binding material. 
     
     
         21 . The method of  claim 20 , wherein the binding material comprises an epoxy filled with one or more inorganic fillers. 
     
     
         22 . The method of  claim 21 , wherein the inorganic fillers include one of either silicon dioxide or silicon carbide. 
     
     
         23 . Apparatus for fabricating a carrier having a top surface and a bottom surface, according to the method of  claim 1 , comprising:
 a spool carrying metal foil forming said conductive portion;   a molding tool for receiving metal foil from the spool and depositing dielectric material to a specified thickness and shape on said metal foil, to form said dielectric portion; and   a downstream processing system for filling the one or more contact island cavities with solder metal, selectively metal plating the conductive portion, selectively etching the conductive portion, and applying solder resist to the selectively plated and etched top surface of the conductive portion.   
     
     
         24 . The apparatus of  claim 23 , wherein said metal foil is copper of thickness less than at least one of  18 um or  10 um. 
     
     
         25 . Apparatus for fabricating a carrier having a top surface and a bottom surface, according to the method of  claim 1 , comprising:
 a mold having a top mold portion and a bottom mold portion for receiving and molding dielectric material to a specified thickness and shape according to surface patters of the top mold portion and a bottom mold portion; and   a downstream processing system for metalizing exposed surfaces of the dielectric portion, filling the one or more contact island cavities with solder metal, selectively metal plating the conductive portion, selectively etching the conductive portion, and applying solder resist to the selectively plated and etched top surface of the conductive portion.   
     
     
         26 . A carrier fabricated according to the method of  claim 1 .