Scribe street width reduction by deep trench and shallow saw cut

Abstract

In a method to singulate a semiconductor wafer ( 100 ) into chips, trench streets ( 107 ) of predetermined depth ( 105 a ) are formed across the first, active wafer surface ( 102 ) to define the outline of the chips ( 101 ). Thereafter, the fabrication of the active first wafer surface is completed and protected. Then, the wafer is flipped to expose the second wafer surface ( 103 ), and the wafer is subjected to a cutting saw. The saw is aligned with the trenches in the first surface so that the saw cuts the second surface along streets ( 106 ), which extend the trenches through the wafer. The saw is stopped cutting at a depth ( 105 b ), when the saw streets just coalesce with the trench streets, respectively, whereby the chips are completely singulated.

1 . A semiconductor chip having a top surface a bottom surface, comprising: 
 a edge surface including a first portion and a second portion;    the first portion adjacent the top surface having an etched surface free of microcracks and saw marks;    the second portion adjacent the bottom surface recessed from the first portion; and    the top surface including a perimeter approximately rectangular.    
     
     
         2 . The semiconductor chip according to  claim 1  further including in said top surface an integrated circuit.  
     
     
         3 . The semiconductor chip according to  claim 1  further including in said top surface a discrete device.  
     
     
         4 . The semiconductor chip according to  claim 1  wherein the material for said semiconductor chip is silicon.  
     
     
         5 . The semiconductor chip according to  claim 1  wherein the material for said semiconductor chip is gallium arsenide.  
     
     
         6 - 26 . (canceled)  
     
     
         27 . The semiconductor chip according to  claim 1 , in which the second portion has a sawed surface with saw marks.  
     
     
         28 . The semiconductor chip according to  claim 1 , in which the first portion is etched chemically.  
     
     
         29 . The semiconductor chip according to  claim 1 , in which the first portion is etched with aid of plasma.  
     
     
         30 . The semiconductor chip according to  claim 1 , in which the second portion is about 20 μm distant from the top surface.  
     
     
         31 . The semiconductor chip according to  claim 1 , in which the second portion is less than 20 μm distant from the top surface.