ADHESIVE COMPOSITION
An adhesive composition for flip-chip-mounting a chip component on a circuit board contains an alicyclic epoxy compound, an alicyclic acid anhydride curing agent, and an acrylic resin. The amount of the alicyclic acid anhydride curing agent is 80 to 120 parts by mass based on 100 parts by mass of the alicyclic epoxy compound, and the amount of the acrylic resin is 5 to 50 parts by mass based on 100 parts by mass of the total amount of the alicyclic epoxy compound, the alicyclic acid anhydride curing agent, and the acrylic resin. The acrylic resin is a resin obtained by copolymerization of 100 parts by mass of alkyl (meth)acrylate and 2 to 100 parts by mass of glycidyl methacrylate and having a water absorption rate of 1.2% or less.
1 . An adhesive composition used to flip-chip-mount a chip component on a circuit board, the adhesive composition comprising an alicyclic epoxy compound, an alicyclic acid anhydride curing agent, and an acrylic resin, wherein
an amount of the alicyclic acid anhydride curing agent is 80 to 120 parts by mass based on 100 parts by mass of the alicyclic epoxy compound, and an amount of the acrylic resin is 5 to 50 parts by mass based on 100 parts by mass of the total amount of the alicyclic epoxy compound, the alicyclic acid anhydride curing agent, and the acrylic resin, and
the acrylic resin is a resin that is obtained by copolymerization of 100 parts by mass of alkyl(meth)acrylate and 2 to 100 parts by mass of glycidyl methacrylate and that has a water absorption rate of 1.2% or less.
2 . The adhesive composition according to claim 1 , wherein a weight average molecular weight of the acrylic resin is 5,000 to 200,000 and a glass transition temperature of the acrylic resin is 50° C. or lower.
3 . The adhesive composition according claim 1 , wherein the alicyclic epoxy compound is glycidyl hexahydrobisphenol A or 3,4-epoxycyclohexenylmethyl-3′,4′-epoxycyclohexene carboxylate, and the alicyclic acid anhydride curing agent is methylhexahydrophthalic anhydride.
4 . The adhesive composition according to claim 1 , wherein the alkyl(meth)acrylate is ethyl acrylate, butyl acrylate, or 2-ethelhexyl acrylate.
5 . The adhesive composition according to claim 1 , comprising a thermal antioxidant in an amount of 0.01 to 10 parts by mass, a metal deactivator in an amount of 0.01 to 10 parts by mass, and a ultraviolet absorbing agent in an amount of 0.01 to 10 parts by, based on 100 parts by mass of the total amount of the alicyclic epoxy compound, the alicyclic acid anhydride curing agent, and the acrylic resin.
6 . The adhesive composition according to claim 1 , comprising 2-methyl-4-ethylimidazol as a curing accelerator in an amount of 0.01 to 10 parts by mass based on 100 parts by mass of the total amount of the alicyclic epoxy compound, the alicyclic acid anhydride curing agent, and the acrylic resin.
7 . A connection structure in which a chip component is flip-chip-mounted on a circuit board using the adhesive composition according to claim 1 .
8 . The connection structure according to claim 7 , wherein the chip component is an LED element.