Mold shave apparatus and injection molded soldering process

Abstract

An apparatus and a method for the removal of excess solder or contaminant, which are encountered on the surfaces of injection mold prior to the transfer of a solder on a silicon wafer. More particularly, there is provided for the removal of excess solder, which may be present on a mold surface, without removing any solder, which is located in cavities formed in the mold, and wherein the solder is applied through an injection molded soldering process.

1 . An apparatus for shaving excess solder from the surface of a mold plate containing a multiplicity of cavities each filled with a volume of solder, said apparatus comprising:
 a support member mounting a table for movement in x-y directions;   a vacuum table on said movable table for retaining thereon a mold plate having a multiplicity of cavities formed in an upper surface thereof for filling with solder material;   a bridge-shaped frame mounted on said support member extending over said mold plate in spaced relationship therewith;   a heating device pivotably mounted on said frame and having a heatable shaving blade attached to a lower end of said device for displacement across the surface of said mold plate; and   a cylinder movable in a z-direction connected to, respectively, said bridge-shaped frame and to a structure having a rotary plate attached thereto for imparting rotational movement to said shaving blade, whereby said shaving blade is contactingly movable across the surface of said mold plate for scraping excess solder therefrom.   
   
   
       2 . An apparatus as claimed in  claim 1 , wherein said heating device comprises a nitrogen heater for heating said shaving blade to a temperature softening the solder in said cavities in the absence of melting while scraping excess solder from the surface of said mold plate. 
   
   
       3 . An apparatus as claimed in  claim 1 , wherein said mold plate is heated concurrently with the heating of said shaving blade to facilitate removal of excess solder, oxidants and contaminants from the surface of said mold plate. 
   
   
       4 . An apparatus as claimed in  claim 1 , wherein the speed of movement, variations in the cutting edge of said shaving blade, and temperature control is provided for by said shaving blade in correlation with the selected type of material and composition of the solder. 
   
   
       5 . An apparatus as claimed in  claim 1 , wherein the shaving blade is selected from the group of materials consisting of ASME 1095 tool steel, zirconia and stainless steel. 
   
   
       6 . A method of shaving excess solder from the surface of a mold plate containing a multiplicity of cavities each filled with a volume of solder, said method comprising:
 providing a support member mounting a table for movement in x-y directions;   arranging a vacuum table on said movable table for retaining thereon a mold plate having a multiplicity of cavities formed in an upper surface thereof for filling with solder material;   mounting a bridge-shaped frame to extend over said support member and over said mold plate in spaced relationship therewith;   pivotably mounting a heating device on said frame, and attaching a heatable shaving blade to a lower end of said device for displacement across the surface of said mold plate; and   connecting a cylinder which is movable in a z-direction to, respectively, said bridge-shaped frame and to a structure which has a rotary plate attached thereto for imparting rotational movement to said shaving blade, whereby said shaving blade is contactingly movable across the surface of said mold plate for scraping excess solder therefrom.   
   
   
       7 . A method as claimed in  claim 6 , wherein said heating device comprises a nitrogen heater for heating said shaving blade to a temperature softening the solder in said cavities in the absence of melting while scraping excess solder from the surface of said mold plate. 
   
   
       8 . A method as claimed in  claim 6 , wherein said mold plate is heated concurrently with the from the surface of said mold plate. 
   
   
       9 . A method as claimed in  claim 6 , wherein the speed of movement, variations in the cutting edge of said shaving blade, and temperature control is provided for by said shaving blade in correlation with the selected type of material and composition of the solder. 
   
   
       10 . A method as claimed in  claim 6 , wherein the shaving blade is selected from the group of materials consisting of ASME 1095 tool steel, zirconia and stainless steel. 
   
   
       11 . A method as claimed in  claim 6 , wherein the shaving blade remains stationary and the relative movement between said shaving blade and mold plate surface is accomplished by moving said mold plate. 
   
   
       12 . A method as claimed in  claim 11 , wherein the method of shaving the mold plate surface is effected in-line and immediate following the method of filling the mold plate cavities.