Use of a U-groove as an alternative to using a V-groove for protection against dicing induced damage in silicon

Abstract

The present disclosure relates that by modifying chip die dicing methodology to a U-groove profile from a V-groove profile by modifying the second etch step to be a dry etch instead of a wet etch results in a direct cost savings by eliminating a more expensive process step, as well as the need for stripping the developed photoresist layer. Furthermore, going to a U-groove profile accomplishes additional indirect and greater cost savings resulting from increased process throughput, improved yield, and reduced metal layer defects.

1 . A method for dicing die from a semiconductor wafer while allowing a very close cut of a die edge relative to active elements on the die without damaging the active elements comprising: 
 etching a U-groove via a dry etch in the semiconductor wafer; and    sawing the semiconductor wafer along the U-groove where one edge of the saw is substantially in alignment with the bottom of the U-groove.    
   
   
       2 . The method of  claim 1  wherein the dry etch uses a combination of gases comprising SF 6  and O 2 .  
   
   
       3 . The method of  claim 2  wherein the semiconductor wafer is comprised of amorphous silicon.  
   
   
       4 . The method of  claim 2  wherein the semiconductor wafer is comprised of gallium arsenide  
   
   
       5 . The method of  claim 2  wherein the semiconductor wafer is comprised of a III-V compound.  
   
   
       6 . The method of  claim 2  wherein the semiconductor wafer is comprised of silicon on insulator.  
   
   
       7 . The method of  claim 2  wherein the U-groove is approximately 4 microns in depth.  
   
   
       8 . The method of  claim 2  wherein the U-groove is approximately 3.5 to 5.5 microns in depth.  
   
   
       9 . The method of  claim 7  wherein the U-groove is approximately 6 to 10 microns in width.  
   
   
       10 . A method for dicing die from a semiconductor wafer while allowing a very close cut of a die edge relative to active elements on the die without damaging the active elements comprising: 
 etching a U-groove approximately 3.5 to 5.5 microns in depth via a dry etch in the semiconductor wafer; and    sawing the semiconductor wafer along the U-groove where one edge of the saw is substantially in alignment with the bottom of the U-groove.    
   
   
       11 . The method of  claim 10  wherein the dry etch uses a combination of gases comprising SF 6  and O 2 .  
   
   
       12 . The method of  claim 10  wherein the semiconductor wafer is comprised of amorphous silicon.  
   
   
       13 . The method of  claim 10  wherein the semiconductor wafer is comprised of gallium arsenide  
   
   
       14 . The method of  claim 10  wherein the semiconductor wafer is comprised of a III-V compound.  
   
   
       15 . The method of  claim 10  wherein the semiconductor wafer is comprised of silicon on insulator.  
   
   
       16 . The method of  claim 10  wherein the U-groove is approximately 4 microns in depth.  
   
   
       17 . The method of  claim 10  wherein the U-groove is approximately 6 to 10 microns in width.