Heat-curable resin composition for semiconductor encapsulation

Abstract

Provided is a highly versatile heat-curable resin composition for semiconductor encapsulation that exhibits a favorable water resistance and abradability when used to encapsulate a semiconductor device; and a superior fluidity and a small degree of warpage even when used to perform encapsulation on a large-sized wafer. The heat-curable resin composition for semiconductor encapsulation comprises: (A) a cyanate ester compound having not less than two cyanato groups in one molecule, and containing a particular cyanate ester compound that has a viscosity of not higher than 50 Pa·s; (B) a phenol curing agent containing a resorcinol-type phenolic resin; (C) a curing accelerator; (D) an inorganic filler surface-treated with a silane coupling agent; and (E) an ester compound.

What is claimed is: 
     
       1. A heat-curable resin composition for semiconductor encapsulation, comprising:
 (A) a cyanate ester compound having not less than two cyanato groups in one molecule, the cyanate ester compound containing a cyanate ester compound (A-1) represented by the following formula (1) and exhibiting a viscosity of not higher than 50 Pa·s at 23° C. when measured by a B-type rotary viscometer in accordance with a method described in JIS K7117-1:1999 
 
       
         
           
           
               
               
           
         
         wherein n represents an integer of 0 or 1; each of R 1  and R 2  represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and R 3  represents a divalent linking group selected from the groups expressed by the following formulae (2) to (5) 
       
       
         
           
           
               
               
           
         
         (B) a phenol curing agent containing a resorcinol-type phenolic resin represented by the following formula (6) 
       
       
         
           
           
               
               
           
         
         wherein n represents an integer of 0 to 10; each of R 1  and R 2  independently represents a hydrogen atom or a monovalent group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an allyl group and a vinyl group; and x represents 1 or 2; 
         (C) a curing accelerator in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the component (A); 
         (D) an inorganic filler that is spherical, has an average particle diameter of 1 to 20 μm when measured by a laser diffraction method, is in an amount of 1,200 to 2,200 parts by mass per 100 parts by mass of a sum total of the components (A) and (B), and has been surface-treated with a silane coupling agent represented by the following formula (7)
   R 1   a (OR 2 ) (3-a) Si—C 3 H 6 —R 3   (7)
 
 
         wherein a represents an integer of 0 to 3; R 1  represents a methyl group or an ethyl group; R 2  represents an alkyl group having 1 to 3 carbon atoms; and R 3  represents a group selected from the group consisting of the nitrogen-containing functional groups represented by the following formulae (8) to (11) 
       
       
         
           
           
               
               
           
         
       
       and
 (E) an ester compound that is in an amount of 1 to 10 parts by mass per 100 parts by mass of the sum total of the components (A) and (B), and is represented by the following formula (12)
   R 4 —CH 2 CH 2 —NH—CH 2 CH 2 —R 5   (12)
 
 
 
       wherein each of R 4  and R 5  represents a saturated ester residue having 2 to 30 carbon atoms. 
     
     
       2. The heat-curable resin composition for semiconductor encapsulation according to  claim 1 , wherein cyanate ester compound content in the component (A) except for the cyanate ester compound (A-1) represented by the formula (1) is an amount of smaller than 10% by mass with respect to the whole amount of the component (A). 
     
     
       3. The heat-curable resin composition for semiconductor encapsulation according to  claim 1 , wherein the resorcinol-type phenolic resin represented by the formula (6) is contained in the component (B) by an amount of 10 to 100% by mass with respect to the whole amount of the component (B). 
     
     
       4. The heat-curable resin composition for semiconductor encapsulation according to  claim 1 , wherein cyanato groups in the cyanate ester compound as the component (A) are in an amount of 0.5 to 100 equivalents per 1 equivalent of hydroxyl groups in the phenol curing agent as the component (B). 
     
     
       5. The heat-curable resin composition for semiconductor encapsulation according to  claim 1 , exhibiting a linear expansion coefficient of 3.0 to 5.0 ppm/° C. as a result of measuring a 5×5×15 mm specimen at a rate of temperature increase of 5° C./min and under a load of 19.6 mN, in accordance with a method described in JIS K 7197:2012. 
     
     
       6. A method for producing a resin-encapsulated semiconductor device, comprising:
 a step of using a cured product of the heat-curable resin composition for semiconductor encapsulation as set forth in  claim 1  to collectively encapsulate an entire silicon wafer or substrate with at least one semiconductor element mounted thereon, wherein 
 the heat-curable resin composition for semiconductor encapsulation is applied either in a pressurized manner, or in a depressurized manner under a vacuum atmosphere, before being heated and cured to encapsulate the semiconductor element.