Adhesive composition, process for producing the same, adhesive film using the same, substrate for mounting semiconductor and semiconductor device

Abstract

The present invention provides an adhesive composition which comprises (a) an epoxy resin, (b) a curing agent and (c) a polymer compound incompatible with said epoxy resin, and further optionally comprises (d) a filler and/or (e) a curing accelerator; a process for producing an adhesive composition, comprising: mixing (a) the epoxy resin and (b) the curing agent with (d) the fillers followed by mixing the resultant mixture with (c) the polymer compound incompatible with the epoxy resin; an adhesive film comprising the above-mentioned adhesive composition formed into a film; a substrate for mounting semiconductor comprising a wiring board and the above-mentioned adhesive film disposed thereon on its side where chips are to be mounted; and a semiconductor device which comprises the above-mentioned adhesive film or the substrate for mounting semiconductor.

1 . An adhesive film comprising an adhesive composition which comprises:
 (a) an epoxy resin;   (b) a curing agent which mainly comprises a phenolic resin having a hydroxyl equivalent of 150 g/eq or more; and   (c) a polymer compound incompatible with said epoxy resin,   wherein a ratio of A/B is 0.24:1 to 1:1, where A represents a total weight of (a) the epoxy resin and (b) the curing agent and B represents a weight of (c) the polymer compound incompatible with the epoxy resin, and the adhesive composition has been formed into a film,   wherein the components of the adhesive composition are separated into two phases after being cured as viewed in the cross-section thereof, and   wherein (b) the curing agent is a phenolic resin represented by the following general formula (I):   
     
       
         
         
             
             
         
       
     
     wherein R 1  each may be the same or different from each other and represents a hydrogen atom, a straight or branched alkyl group having 1 to 10 carbon atoms, a cyclic alkyl group, an aralkyl group, an alkenyl group, a hydroxyl group, an aryl group, or a halogen atom; n represents an integer of 1 to 3; and m represents an integer of 0 to 50, and
 wherein (b) the curing agent exhibits a weight loss by heating at 350° C. (temperature elevation rate: 5° C./min.; atmosphere:nitrogen gas) of less than 5% by weight as measured by a thermo-gravimetric analyzer (TGA). 
 
   
   
       2 . The adhesive film according to  claim 1 , wherein (a) the epoxy resin is a solid epoxy resin having a softening point of 50° C. or more as measured by a ring and ball method. 
   
   
       3 . The adhesive film according to  claim 1 , wherein (a) the epoxy resin has no mutagen. 
   
   
       4 . The adhesive film according to  claim 1 , wherein the phenolic resin represented by general formula (I) has a water absorption of 2% by volume or less. 
   
   
       5 . The adhesive film according to  claim 1 , wherein (c) the polymer compound incompatible with the epoxy resin is a functional group-containing acrylic copolymer. 
   
   
       6 . The adhesive film according to  claim 5 , wherein the functional group-containing acrylic copolymer is an epoxy group-containing acrylic copolymer. 
   
   
       7 . The adhesive film according to  claim 6 , wherein the epoxy group-containing acrylic copolymer contains 0.5 to 6% by weight of glycidyl acrylate or glycidyl methacrylate as a starting material therefor. 
   
   
       8 . The adhesive film according to  claim 5 , wherein the functional group-containing acrylic copolymer has a weight average molecular weight of 100,000 or more. 
   
   
       9 . The adhesive film according to  claim 5 , wherein the functional group-containing acrylic copolymer has a glass transition temperature of −50° C. to 30° C. 
   
   
       10 . The adhesive film according to  claim 1 , which further comprises (e) a curing accelerator. 
   
   
       11 . The adhesive film according to  claim 10 , wherein (e) the curing accelerator is an imidazole compound. 
   
   
       12 . The adhesive film according to  claim 1 , wherein the two phases comprise a sea phase and an islands phase, and wherein, a length of an outer periphery of the islands phase represented by S and an area of a cross-section represented by V satisfy a relationship represented by the following formula (1):
     S/√V> 3.6  (1).   
   
   
       13 . The adhesive film according to  claim 1 , which satisfies at least one of the following requirements (i) and (ii):
 (i) the adhesive composition gives a cured product having a storage elastic modulus at 240° C. of 1 to 20 MPa; and   (ii) the adhesive composition has pores having an average diameter of 0.01 μm to 2 μm after being cured and a volume percentage of the pores after being cured is 0.1 to 20% by volume.   
   
   
       14 . The adhesive film according to  claim 1 , which exhibits lowering in flow after 72 hours at 60° C. of 50% or less. 
   
   
       15 . The adhesive film according to  claim 1 , wherein (a) the epoxy resin is a bisphenol A epoxy resin, (b) the curing agent is a zylok phenolic resin, and (c) the polymer compound incompatible with the epoxy resin is an epoxy group-containing acrylic rubber. 
   
   
       16 . The adhesive film according to  claim 1 , wherein said adhesive composition gives a cured product having a storage elastic modulus at 240° C. of 1 to 20 MPa. 
   
   
       17 . The adhesive film according to  claim 16 , having pores with an average diameter of 0.01 μm to 2 μm after being cured, and a volume percentage of the pores in the composition after being cured is 0.1 to 20% by volume. 
   
   
       18 . The adhesive film according to  claim 1 , having pores with an average diameter of 0.01 μm to 2 μm after being cured, and a volume percentage of the pores in the composition after being cured is 0.1 to 20% by volume. 
   
   
       19 . The adhesive film according to  claim 1 , wherein visible light transmittance of a film 50 μm thick of said epoxy resin and polymer compound, having a component ratio of 1:1, prepared from a varnish of said epoxy resin and said polymer compound, is less than 30%. 
   
   
       20 . The adhesive film according to  claim 1 , wherein amount of epoxy resin in the adhesive film is less than amount of said polymer compound in said film. 
   
   
       21 . An adhesive film comprising an adhesive composition which comprises:
 (a) an epoxy resin;   (b) a curing agent which mainly comprises a phenolic resin having a hydroxyl equivalent of 150 g/eq or more; and   (c) a polymer compound incompatible with said epoxy resin,   wherein a ratio of A/B is 0.24:1 to 1:1, where A represents a total weight of (a) the epoxy resin and (b) the curing agent and B represents a weight of (c) the polymer compound incompatible with the epoxy resin, and the adhesive composition has been formed into a film,   wherein the adhesive film gives a cured product having a storage elastic modulus at 240° C. of 1 to 20 MPa,   wherein (b) the curing agent is a phenolic resin represented by the following general formula (I):   
     
       
         
         
             
             
         
       
     
     wherein R 1  each may be the same or different from each other and represents a hydrogen atom, a straight or branched alkyl group having 1 to 10 carbon atoms, a cyclic alkyl group, an aralkyl group, an alkenyl group, a hydroxyl group, an aryl group, or a halogen atom; n represents an integer of 1 to 3; and m represents an integer of 0 to 50, wherein (b) the curing agent exhibits a weight loss by heating at 350° C. (temperature elevation rate: 5° C./min.; atmosphere:nitrogen gas) of less than 5% by weight as measured by a thermo-gravimetric analyzer (TGA). 
   
   
       22 . An adhesive film comprising an adhesive composition which comprises:
 (a) an epoxy resin;   (b) a curing agent which mainly comprises a phenolic resin having a hydroxyl equivalent of 150 g/eq or more; and   (c) a polymer compound incompatible with said epoxy resin,   wherein a ratio of A/B is 0.24:1 to 1:1, where A represents a total weight of (a) the epoxy resin and (b) the curing agent and B represents a weight of (c) the polymer compound incompatible with the epoxy resin, and the adhesive composition has been formed into a film,   wherein said adhesive film has pores with an average diameter of 0.01 μm to 2 μm after being cured, and a volume percentage of the pores in the composition after being cured is 0.1 to 20% by volume,   wherein (b) the curing agent is a phenolic resin represented by the following general formula (I):   
     
       
         
         
             
             
         
       
     
     wherein R 1  each may be the same or different from each other and represents a hydrogen atom, a straight or branched alkyl group having 1 to 10 carbon atoms, a cyclic alkyl group, an aralkyl group, an alkenyl group, a hydroxyl group, an aryl group, or a halogen atom; n represents an integer of 1 to 3; and m represents an integer of 0 to 50, wherein (b) the curing agent exhibits a weight loss by heating at 350° C. (temperature elevation rate: 5° C./min.; atmosphere:nitrogen gas) of less than 5% by weight as measured by a thermo-gravimetric analyzer (TGA). 
   
   
       23 . The adhesive film according to  claim 21 , wherein (a) the epoxy resin is a bisphenol A epoxy resin, (b) the curing agent is a zylok phenolic resin, and (c) the polymer compound incompatible with the epoxy resin is an epoxy group-containing acrylic rubber. 
   
   
       24 . The adhesive film according to  claim 22 , wherein (a) the epoxy resin is a bisphenol A epoxy resin, (b) the curing agent is a zylok phenolic resin, and (c) the polymer compound incompatible with the epoxy resin is an epoxy group-containing acrylic rubber. 
   
   
       25 . The adhesive film according to  claim 1 , wherein equivalents ratio of epoxy equivalent to hydroxyl equivalent of the epoxy resin and phenolic resin is in the range of 0.70:0.30 to 0.30:0.70. 
   
   
       26 . The adhesive film according to  claim 1 , wherein the curing agent is included in an amount of 0.01 to 5.0 equivalents based on 1 mol of the epoxy group. 
   
   
       27 . The adhesive film according to  claim 1 , wherein the adhesive composition exhibits a weight loss on heating at 270° C. of 2% by weight or less. 
   
   
       28 . The adhesive film according to  claim 1 , wherein the adhesive film has the property that it can be laminated as a film on a substrate, for acting as an adhesive. 
   
   
       29 . The adhesive film according to  claim 28 , wherein said substrate is a semiconductor chip.