Energy Ray-Curable Polymer, an Energy Ray-Curable Adhesive Composition, an Adhesive Sheet and a Processing Method of a Semiconductor Wafer

Abstract

In a pressure-sensitive adhesive composition or a pressure-sensitive adhesive sheet containing an energy ray-curable polymer, problems associated with the volatilization of a low molecular weight compound contained in the composition are overcome. An energy ray-curable polymer characterized by comprising a radical generating group, which is capable of initiating a polymerization reaction upon excitation with an energy ray, and an energy ray-polymerizable group bonded together in the main or side chain.

1 . An energy ray-curable acrylic polymer having a radical generating group capable of initiating polymerization reaction under the excitation by an energy ray, and an energy ray-polymerizable group bonded to a main chain or a side chain of the polymer. 
     
     
         2 . The energy ray-curable acrylic polymer as set forth in  claim 1  wherein said radical generating group includes a phenyl carbonyl group which may comprise a substituent group in an aromatic ring. 
     
     
         3 . The energy ray-curable acrylic polymer as set forth in  claim 2  wherein said radical generating group is derived from a monomer obtained by adding a compound comprising a polymerizable double bond to a hydroxyl group of a photo polymerization initiator comprising hydroxyl group. 
     
     
         4 . The energy ray-curable acrylic polymer as set forth  claim 3  having a weight average molecular weight of 300,000 to 1,600,000. 
     
     
         5 . An energy ray-curable adhesive composition comprising the energy ray-curable acrylic polymer as set forth in  claim 4 . 
     
     
         6 . An adhesive sheet comprising a substrate and an energy ray-curable adhesive layer formed thereon, and said energy ray-curable adhesive layer comprising the energy ray-curable adhesive composition as set forth in  claim 5 . 
     
     
         7 . The adhesive sheet as set forth in  claim 6  used for a semiconductor wafer processing. 
     
     
         8 . A processing method of a semiconductor wafer comprising the step of adhering the energy ray-curable adhesive layer of the adhesive sheet as set forth in  claim 7  to a circuit surface of the semiconductor wafer formed with the circuit on the front surface, and performing the backside processing of the wafer. 
     
     
         9 . The processing method of the semiconductor wafer as set forth in  claim 8  wherein said backside processing of the semiconductor wafer is the backside grinding. 
     
     
         10 . The processing method of the semiconductor wafer comprising the step of adhering the energy ray-curable adhesive layer of the adhesive sheet as set forth in  claim 7  to the backside of the semiconductor wafer formed with the circuit on the front surface, and performing dicing of the wafer. 
     
     
         11 . The processing method of the semiconductor wafer as set forth in  claim 10  further comprising the step involving a heat application or a heat generation. 
     
     
         12 . An energy ray-curable adhesive composition comprising:
 an energy ray-curable polymer having a radical generating group capable of initiating polymerization reaction under the excitation by an energy ray, and an energy ray-polymerizable group bonded to a main chain or a side chain of the polymer.   
     
     
         13 . The energy ray-curable adhesive composition as set forth in  claim 12  wherein said radical generating group includes a phenyl carbonyl group which may comprise a substituent group in an aromatic ring. 
     
     
         14 . The energy ray-curable adhesive composition as set forth in  claim 13  wherein said radical generating group is derived from a monomer obtained by adding a compound comprising a polymerizable double bond to a hydroxyl group of a photo polymerization initiator comprising hydroxyl group. 
     
     
         15 . The energy ray-curable adhesive composition as set forth in  claim 14  having a weight average molecular weight of 300,000 to 1,600,000. 
     
     
         16 . An adhesive sheet comprising a substrate and an energy ray-curable adhesive layer formed thereon comprising the energy ray-curable adhesive composition as set forth in  claim 12 ,
 wherein an adhesive force against a mirror surface of the semiconductor wafer is 2000 to 1500 mN/25 mm before the energy ray irradiation and after the energy ray irradiation the adhesive force is 1 to 50% of that before the irradiation.   
     
     
         17 . The adhesive sheet as set forth in  claim 16  used for a semiconductor wafer processing. 
     
     
         18 . A processing method of a semiconductor wafer comprising the step of adhering the energy ray-curable adhesive layer of the adhesive sheet as set forth in  claim 17  to a circuit surface of the semiconductor wafer formed with the circuit on the front surface, and performing the backside processing of the wafer. 
     
     
         19 . The processing method of the semiconductor wafer as set forth in  claim 18  wherein said backside processing of the semiconductor wafer is the backside grinding. 
     
     
         20 . The processing method of the semiconductor wafer comprising the step of adhering the energy ray-curable adhesive layer of the adhesive sheet as set forth in  claim 17  to the backside of the semiconductor wafer formed with the circuit on the front surface, and performing dicing of the wafer. 
     
     
         21 . The processing method of the semiconductor wafer as set forth in  claim 20  further comprising the step involving a heat application or a heat generation.