ANISOTROPIC CONDUCTIVE FILM
In an anisotropic conductive film formed by laminating an insulating adhesive layer containing a polymerizable acrylic compound, a film-forming resin, and a polymerization initiator and a conductive particle-containing layer containing a polymerizable acrylic compound, a film-forming resin, a polymerization initiator, and conductive particles, the insulating adhesive layer and the conductive particle-containing layer each contain a thiol compound in order not to decrease the adhesion strength to an adherend and to improve connection reliability. Examples of the thiol compound may include pentaerythritol tetrakis(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolpropane tris(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptopropionate).
1 . An anisotropic conductive film formed by laminating an insulating adhesive layer containing a polymerizable acrylic compound, a film-forming resin, and a polymerization initiator and a conductive particle-containing layer containing a polymerizable acrylic compound, a film-forming resin, a polymerization initiator, and conductive particles, wherein
the insulating adhesive layer and the conductive particle-containing layer each contain a thiol compound.
2 . The anisotropic conductive film according to claim 1 , wherein amounts of the thiol compounds in the insulating adhesive layer and the conductive particle-containing layer are 0.5 to 5% by mass and 0.3 to 4% by mass, respectively.
3 . The anisotropic conductive film according to claim 1 , wherein the amount of the thiol compound in the insulating adhesive layer is equal to or more than the amount of the thiol compound in the conductive particle-containing layer.
4 . The anisotropic conductive film according to claim 1 , wherein the thiol compounds in the insulating adhesive layer and the conductive particle-containing layer are separately a compound selected from the group consisting of pentaerythritol tetrakis(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, trimethylolpropane tris(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptopropionate).
5 . The anisotropic conductive film according to claim 1 , wherein the polymerization initiator is an organic peroxide.
6 . The anisotropic conductive film according to claim 5 , wherein: the polymerization initiator contained in the conductive particle-containing layer includes two types of organic peroxides having different one-minute half-life temperatures; one organic peroxide which has a higher one-minute half-life temperature among the two types of organic peroxides decomposes to produce benzoic acid or a derivative thereof, and the polymerization initiator contained in insulating adhesive layer is the organic peroxide which has a higher one-minute half-life temperature.
7 . The anisotropic conductive film according to claim 6 , wherein an organic peroxide which has a lower one-minute half-life temperature among the two types of organic peroxides is dilauroyl peroxide, and the organic peroxide which has a higher one-minute half-life temperature is dibenzoyl peroxide.
8 . The anisotropic conductive film according to claim 1 , wherein the polymerizable acrylic compound contains a phosphate ester acrylate, and the film-forming resin contains a polyester resin, a polyurethane resin, or a phenoxy resin.
9 . A connection structure produced by connecting a connection portion of a first wiring substrate and a connection portion of a second wiring substrate through the anisotropic conductive film according to claim 7 by anisotropic conductive connection.
10 . The connection structure according to claim 9 , wherein the first wiring substrate is a chip-on film substrate or a tape carrier package substrate, the second wiring substrate is a printed wiring board, and the insulating adhesive layer of the anisotropic conductive film is disposed on a side of the first wiring substrate.
11 . A method for producing a connection structure, comprising: holding the anisotropic conductive film according to claim 1 between a connection portion of a first wiring substrate and a connection portion of a second wiring substrate; temporarily bonding the anisotropic conductive film to the connection portions at a first temperature at which an organic peroxide having a lower one-minute half-life temperature does not decompose; and bonding the anisotropic conductive film to the connection portions by thermocompression bonding at a second temperature at which an organic peroxide having a higher one-minute half-life temperature decomposes.
12 . A connection structure produced by connecting a connection portion of a first wiring substrate and a connection portion of a second wiring substrate through the anisotropic conductive film according to claim 1 by anisotropic conductive connection.