Laminate body, and method for manufacturing thin substrate using the laminate body

Abstract

Provided is a laminated body comprising a substrate to be ground and a support, where the substrate may be ground to a very small (thin) thickness and can then be separated from the support without damaging the substrate. One embodiment is a laminated body comprising a substrate to be ground, a curable silicone adhesive layer in contact with the substrate to be ground, a photothermal conversion layer comprising a light absorbing agent and a heat decomposable resin, and a light transmitting support. After grinding the substrate surface which is opposite that in contact with the adhesive layer, the laminated body is irradiated through the light transmitting layer and the photothermal conversion layer decomposes to separate the substrate and the light transmitting support.

1 . A method for manufacturing a laminated body,
 the laminated body comprising:
 a substrate to be ground; 
 a joining layer in contact with said substrate; 
 a photothermal conversion layer comprising a light absorbing agent and a heat decomposable resin disposed beneath the joining layer; and 
 a light transmitting support disposed beneath the photothermal conversion layer, said method comprising: 
 coating on a light transmitting support a photothermal conversion layer precursor containing a light absorbing agent and a heat decomposable resin solution or a monomer or oligomer as a precursor material of a heat decomposable resin; 
 drying to solidify or curing said photothermal conversion layer precursor to form a photothermal conversion layer on said light transmitting support; 
 applying a curable silicone adhesive to the substrate to be ground or the photothermal conversion layer; 
 joining said substrate to be ground and said photothermal conversion layer through said curable silicone adhesive under reduced pressure, and curing to form a laminated body. 
   
     
     
         2 . The method of  claim 1  wherein said curable silicone adhesive is selected from addition curable silicones, condensation curable silicones, free-radical curable silicones, and cationic curable silicones. 
     
     
         3 . The method of  claim 2 , wherein said curable silicone adhesive further comprises a reinforcing agent. 
     
     
         4 . The method of  claim 1  wherein said substrate is a silicon wafer. 
     
     
         5 . The method of  claim 1  wherein said support is glass. 
     
     
         6 . The method of  claim 2  wherein said curable silicone adhesive is an addition curable silicone adhesive. 
     
     
         7 . The method of  claim 6  wherein said adhesive comprises an ethylenically unsaturated functional group silicone, a hydride functional silicone, and a hydrosilylation catalyst. 
     
     
         8 . The method of  claim 7 , wherein said hydrosilylation catalyst is a photohydrosilylation catalyst. 
     
     
         9 . The method of  claim 1 , wherein said silicone adhesive is at least one free radical-cure silicone adhesive comprising an ethylenically unsaturated silicone. 
     
     
         10 . The method of  claim 1 , wherein said silicone adhesive is at least one condensation curable silicone. 
     
     
         11 . The method of  claim 1 , wherein said silicone adhesive is at least one cationic curable silicone. 
     
     
         12 . The method of  claim 11  wherein said cationic curable silicone is an epoxy silicone. 
     
     
         13 . The method of  claim 1  wherein the curable silicone is cured by exposure to actinic radiation. 
     
     
         14 . A method for producing a semiconductor chip, comprising:
 applying a photothermal conversion layer comprising a light-absorbing agent and a heat decomposable resin on a light-transmitting support,   preparing a semiconductor wafer having a circuit face with a circuit pattern and a non-circuit face on the side opposite of said circuit face, laminating said semiconductor wafer and said light-transmitting support through a curable silicone adhesive by placing said circuit face and said photothermal conversion layer to face each other, and irradiating light through said light-transmitting support side to cure the curable silicone adhesive layer, thereby forming a laminated body having a non-circuit face on the outside surface,   grinding the non-circuit face of said semiconductor wafer until said semiconductor wafer reaches a desired thickness,   irradiating radiation energy through said light-transmitting support side to decompose said photothermal conversion layer, thereby causing separation into semiconductor wafer having said adhesive layer and a light-transmitting support, and removing said silicone adhesive layer from said semiconductor wafer, and optionally dicing the ground semiconductor wafer to cut it into a plurality of semiconductor chips.   
     
     
         15 . The method for producing a semiconductor chip of  claim 14 , wherein a die bonding tape is affixed to the semiconductor wafer before dicing the ground semiconductor wafer. 
     
     
         16 . The method for producing a semiconductor chip of  claim 14 , wherein laminating said semiconductor wafer and said light-transmitting support through a curable silicone adhesive is performed in a vacuum. 
     
     
         17 . The method of  claim 14 , wherein said semiconductor wafer is ground to a thickness of 50 μm or less. 
     
     
         18 . The method of  claim 14  wherein said semiconductor wafer has been partially sawn through on the circuit face. 
     
     
         19 . A laminated body comprising:
 a substrate to be ground;   a curable silicone adhesive joining layer in contact with said substrate;   a photothermal conversion layer comprising a light absorbing agent and a heat decomposable resin disposed beneath the joining layer; and   a light transmitting support disposed beneath the photothermal conversion layer.   
     
     
         20 . A method of providing a thin substrate comprising:
 a) providing a laminated body comprising a substrate to be ground;
 a joining layer comprising a cured silicone in contact with said substrate; 
 a photothermal conversion layer comprising a light absorbing agent and a heat decomposable resin disposed beneath the joining layer; and 
 a light transmitting support disposed beneath the photothermal conversion layer; 
   b) grinding the face of said substrate to a desired thickness,   c) irradiating radiation energy through said light-transmitting support side to decompose said photothermal conversion layer, thereby causing separation into a thin substrate having said adhesive layer and a light-transmitting support, and optionally removing said cured silicone joining layer from said ground substrate.   
     
     
         21 . The method of  claim 20  further comprising the step of dicing the ground substrate into a plurality of ground substrates. 
     
     
         22 . The method of  claim 20  wherein said substrate to be ground comprises a semiconductor wafer, said wafer having a circuit face adjacent said joining layer and a non-circuit face. 
     
     
         23 . The method of  claim 20 , wherein said substrate is ground to a thickness of 50 μm or less. 
     
     
         24 . The method of  claim 20  wherein said substrate has been partially sawn through on the face adjacent the joining layer.