Method of attaching a leadframe to singulated semiconductor dice

Abstract

The present invention is directed to a method of attaching a leadframe to a singulated good die using a wet film adhesive applied in a predetermined pattern on the active surface of the good die, the lead finger of a leadframe, or both. By applying the adhesive only to identified good dice, time and material are saved over a process that applies adhesive to the entire wafer. By attaching the leadframe to the good die with a wet film, it is possible to remove the leadframe from the good die for rework if the good die subsequently tests unacceptable.

1 . A method of attaching at least one semiconductor die to at least one lead of a plurality of leads of a lead frame, comprising: 
 applying an adhesive in a wet film state in a form of one of a liquid and a paste to portions of the semiconductor die for partially curing the adhesive from the wet film state to an intermediate tacky and flowable state; and    removably attaching a portion of the at least one lead of the plurality of leads of the lead frame to a portion of the semiconductor die using the partially cured adhesive for determining if the semiconductor die is one of an acceptable semiconductor die or an unacceptable semiconductor die.    
     
     
         2 . The method of  claim 1 , further comprising: 
 testing the semiconductor die to for determining if it is one of an acceptable semiconductor die or an unacceptable semiconductor die.    
     
     
         3 . The method of  claim 2 , further comprising: 
 identifying criteria for an acceptable semiconductor die including identifying criteria from one of before an acceptable semiconductor die is separated from a semiconductor wafer and after an acceptable semiconductor die is separated from the semiconductor wafer.    
     
     
         4 . The method of  claim 2 , further comprising: 
 applying the adhesive to the acceptable semiconductor die only after the acceptable semiconductor die has been tested.    
     
     
         5 . The method of  claim 1 , further comprising: 
 curing the adhesive after removably attaching the portion of the at least one lead of the plurality of leads of the lead frame to the acceptable semiconductor die.    
     
     
         6 . The method of  claim 1 , wherein the adhesive is applied to more than one separated semiconductor die at a time.  
     
     
         7 . The method of  claim 2 , wherein the at least one lead of the plurality of leads of the lead frame is attached to the acceptable semiconductor die before the adhesive is partially cured to the intermediate tacky and flowable state.  
     
     
         8 . The method of  claim 1 , wherein the adhesive forms an adhesive layer that is between 8 microns and 200 microns thick.  
     
     
         9 . The method of  claim 1 , further comprising: 
 applying the adhesive to the plurality of leads of the lead frame before attaching the at least one lead of the plurality of leads of the lead frame to the acceptable semiconductor die.    
     
     
         10 . An assembly of a semiconductor die and at least one lead of a plurality of leads of a lead frame, comprising: 
 a semiconductor die having an uncured adhesive in a form of one of a liquid and a paste to portions of the semiconductor die for partially curing the adhesive to an intermediate tacky and flowable state; and    removably attaching a portion of the at least one lead of the plurality of leads of the lead frame to a portion of a surface of the semiconductor die using the adhesive when partially cured for determining when the semiconductor die is one of an acceptable semiconductor die or an unacceptable semiconductor die.    
     
     
         11 . The method of  claim 10 , further comprising: 
 testing the semiconductor die to for determining if it is one of an acceptable semiconductor die or an unacceptable semiconductor die.    
     
     
         12 . The method of  claim 11 , further comprising: 
 identifying criteria for an acceptable semiconductor die including identifying criteria from one of before an acceptable semiconductor die is separated from a semiconductor wafer and after an acceptable semiconductor die is separated from the semiconductor wafer.    
     
     
         13 . The method of  claim 11 , further comprising: 
 applying the adhesive to the acceptable semiconductor die only after the acceptable semiconductor die has been tested.    
     
     
         14 . The method of  claim 10 , further comprising: 
 curing the adhesive after removably attaching the portion of the at least one lead of the plurality of leads of the lead frame to the acceptable semiconductor die.    
     
     
         15 . The method of  claim 10 , wherein the adhesive is applied to more than one separated semiconductor die at a time.  
     
     
         16 . The method of  claim 11 , wherein the at least one lead of the plurality of leads of the lead frame is attached to the acceptable semiconductor die before the adhesive is partially cured to the intermediate tacky and flowable state.  
     
     
         17 . The method of  claim 10 , wherein the adhesive forms an adhesive layer that is between 8 microns and 200 microns thick.  
     
     
         18 . The method of  claim 10 , further comprising: 
 applying the adhesive to the plurality of leads of the lead frame before attaching the at least one lead of the plurality of leads of the lead frame to the acceptable semiconductor die.