Underfill material and method for manufacturing semiconductor device by using the same

Abstract

Provided is an underfill material which enables a semiconductor chip to be mounted at a low pressure, and a method for manufacturing a semiconductor device by using the underfill material. The method comprises: a semiconductor chip mounting step configured to mount a semiconductor chip having a solder bump on a substrate via an underfill film including a film forming resin having a weight average molecular weight of not more than 30000 g/mol and a molecular weight distribution of not more than 2.0, an epoxy resin, and an epoxy curing agent; and a reflow step configured to solder-bond the semiconductor chip and the substrate by a reflow furnace. The film forming resin of the underfill material has a weight average molecular weight of not more than 30000 g/mol and a molecular weight distribution of not more than 2.0, and accordingly, the viscosity at the time of heat melting can be reduced, and a semiconductor chip can be mounted at a low pressure.

What is claimed is: 
     
         1 . An underfill material, comprising:
 a film forming resin having a weight average molecular weight of not more than 30000 g/mol, and a molecular weight distribution of not more than 2.0;   an epoxy resin; and   an epoxy curing agent.   
     
     
         2 . The underfill material according to  claim 1 , wherein the above-mentioned epoxy curing agent is an acid anhydride. 
     
     
         3 . The underfill material according to  claim 2 , wherein the above-mentioned film forming resin is a tri-block copolymer of p-hydroxystyrene and ethyl vinyl ether. 
     
     
         4 . The underfill material according to  claim 3 , wherein
 a composition ratio of the above-mentioned p-hydroxystyrene to the above-mentioned ethyl vinyl ether (p-hydroxystyrene/ethyl vinyl ether) is not less than 20/80 and not more than 70/30, and   not less than 15 parts by mass and not more than 90 parts by mass of the above-mentioned epoxy curing agent with respect to 100 parts by mass of epoxy resin are blended.   
     
     
         5 . The underfill material according to  claim 3 , wherein
 a composition ratio of the above-mentioned p-hydroxystyrene to the above-mentioned ethyl vinyl ether (p-hydroxystyrene/ethyl vinyl ether) is not less than 30/70 and not more than 50/50, and   not less than 40 parts by mass and not more than 70 parts by mass of the above-mentioned epoxy curing agent with respect to 100 parts by mass of epoxy resin are blended.   
     
     
         6 . A method of manufacturing a semiconductor device comprises:
 a semiconductor chip mounting step configured to mount a semiconductor chip having a solder bump on a substrate via an underfill film including a film forming resin having a weight average molecular weight of not more than 30000 g/mol and a molecular weight distribution of not more than 2.0, an epoxy resin, and an epoxy curing agent; and   a reflow step configured to solder-bond the above-mentioned semiconductor chip and the above-mentioned substrate by a reflow furnace.