Semiconductor device encapsulated with epoxy resin composition comprising latent catalyst

Abstract

This invention provides a latent catalyst having a structure of phosphonium borate consisting of a monovalent cation portion in which four specific groups are bonded to the phosphorus atom and a monovalent anion portion in which four specific groups are bonded to the boron atom, and a latent catalyst having a structure wherein the above phosphonium borate is the recurring unit and at least two of said recurring unit are connected through at least one of the four specific groups bonded to the boron atom. This invention also provides a thermosetting resin composition comprising such a latent catalyst and an epoxy resin molding material comprising such a latent catalyst and further provides a semiconductor device in which a semiconductor is encapsulated with said epoxy resin molding material.

What is claimed is:  
     
         1 . A latent catalyst composed of a phosphonium borate represented by the general formula (1):  
                   
       wherein R 1 , R 2 , R 3  and R 4  may be the same as or different from one another and each is a monovalent, organic group having an aromatic ring or a heterocyclic ring or a monovalent, aliphatic group and is bonded to the phosphorus atom to form a P—C bond; X 1 , X 2 , X 3  and X 4  may be the same as or different from one another and at least one of them is a group formed when a proton donor having at least one proton capable of being liberated out of the molecule has liberated one proton and each of the others is a monovalent, organic group having an aromatic ring or a heterocyclic ring or a monovalent aliphatic group, the above proton donors satisfying the condition that when 1 g of each of the proton donors is mixed with 50 g of purified water and the resulting mixture is subjected to pressure cooker treatment at 125° C. for 20 hours in a pressure cooker vessel, the electrical conductivity of the extraction water thus obtained becomes not more than 1,000 μS/cm.  
     
     
         2 . A latent catalyst composed of a phosphonium borate represented by the general formula (2):  
                   
       wherein R 5 , R 6 , R 7  and R 8  may be the same as or different from one another and each is a monovalent, organic group having an aromatic ring or a heterocyclic ring or a monovalent, aliphatic group and is bonded to the phosphorus atom to form a P—C bond; Z 1  is an organic group bonding to Y 1  and Y 2 ; Z 2  is an organic group bonding to Y 3  and Y 4 ; each of Y 1  and Y 2  is a group formed when a monovalent, proton-donating substituent has liberated a proton and the substituents Y 1  and Y 2  in the same molecule are bonded to the boron atom to form a chelate structure; each of Y 3  and Y 4  is a group formed when a monovalent, proton-donating substituent has liberated a proton and the substituents Y 3  and Y 4  are bonded to the boron atom to form a chelate structure; Z 1  and Z 2  may be the same as or different from each other and also Y 1 , Y 2 , Y 3  and Y 4  may be the same as or different from one another; HY 1 Z 1 Y 2 H and HY 3 Z 2 Y 4 H which are the proton donors before the ligands Y 1 Z 1  Y 2  and Y 3 Z 2 Y 4  of boron are formed by liberation of the respective protons satisfying the condition that when 1 g of each of the proton donors is mixed with 50 g of purified water and the resulting mixture is subjected to pressure cooker treatment at 125° C. for 20 hours in a pressure cooker vessel, the electrical conductivity of the extraction water thus obtained becomes not more than 1,000 μS/cm.  
     
     
         3 . A latent catalyst composed of a phosphonium borate represented by the general formula (3):  
                   
       wherein R 9 , R 10 , R 11  and R 12  may be the same as or different from one another and each is a monovalent, organic group having an aromatic ring or a heterocyclic ring or a monovalent, aliphatic group and is bonded to the phosphorus atom to form a P—C bond; Z 3  is an organic group bonding to the substituents Y 5  and Y 6 ; Y 5  and Y 6  may be the same as or different from each other and each is a group formed when a monovalent proton-donating substituent has liberated a proton; the substituents Y 5  and Y 6  in the same molecule are bonded to the boron atom to form a chelate structure; X 5  and X 6  may be the same as or different from each other and each is a group formed when a proton donor having at least one proton capable of being liberated out of the molecule has liberated one proton, or is a monovalent, organic group having an aromatic ring or a heterocyclic ring or a monovalent, aliphatic group; HY 5 Z 3 Y 6 H which is the proton donor before the ligand Y 5 Z 3 Y 6  of boron is formed by the liberation of the protons and HX 5  and HX 6  which are the proton donors in the case where each of X 5  and X 6  is a group formed when a proton donor having at least one proton capable of being liberated out of the molecule has liberated one proton, satisfying the condition that when 1 g of each of the proton donors is mixed with 50 g of purified water and the resulting mixture is subjected to pressure cooker treatment at 125° C. for 20 hours in a pressure cooker vessel, the electrical conductivity of the extraction water thus obtained becomes not more than 1,000 μS/cm.  
     
     
         4 . A latent catalyst having a structure in which the recurring unit is a phosphonium borate consisting of a monovalent cation portion in which four groups are bonded to the phosphorus atom and a monovalent anion portion in which four groups are bonded to the boron atom and at least two of the recurring unit are connected through at least one of the four groups bonding to the boron atom, provided that the group through which the recurring units are connected is a group formed when one proton donor has liberated at least two protons and the group may be composed of the same kind or different kinds; the groups bonding to the phosphorus atom may be the same as or different from one another and each is a monovalent, organic group having an aromatic ring or a heterocyclic ring or a monovalent, aliphatic group and is bonded to the phosphorus atom to form a P—C bond; among the groups bonding to the boron atom, those which do not participate in the connection of the recurring units are each a group formed when a proton donor having at least one proton capable of being liberated out of the molecule has liberated one proton, or a monovalent, organic group having an aromatic ring or a heterocyclic ring or a monovalent, aliphatic group and they may be the same as or different from one another; the proton donors from which the groups bonding to the boron atom result satisfying the condition that when 1 g of each of the proton donors is mixed with 50 g of purified water and the resulting mixture is subjected to pressure cooker treatment at 125° C. for 20 hours in a pressure cooker vessel, the electrical conductivity of the extraction water thus obtained becomes not more than 1,000 μS/cm.  
     
     
         5 . The latent catalyst according to    claim 1   , wherein the proton donor having at least one proton capable of being liberated out of the molecule is an aromatic carboxylic-acid or a phenolic compound.  
     
     
         6 . The latent catalyst according to    claim 2   , wherein the proton donor represented by HY 1 Z 1 Y 2 H or HY 3 Z 2 Y 4 H is an aromatic carboxylic acid or a phenolic compound.  
     
     
         7 . The latent catalyst according to    claim 3   , wherein the proton donor represented by HX 5  or HX 6  in which each of X 5  and X6 is a group formed when a proton donor having at least one proton capable of being liberated out of the molecule has liberated one proton, or represented by HY 5 Z 3 Y 6 H is an aromatic carboxylic acid or a phenolic compound.  
     
     
         8 . The latent catalyst according to    claim 4   , wherein the proton donor which does not participate in the connection of the recurring units or the pro-,on donor which participates in the connection of the recurring units is an aromatic carboxylic acid or a phenolic compound.  
     
     
         9 . The latent catalyst according to    claim 1   , wherein the proton donor having at least one proton capable of being liberated out of the molecule is an aromatic carboxylic acid or a phenolic compound which has at least one substituent selected from the group consisting of carboxyl group and phenolic hydroxyl group and in which two carboxyl groups or a carboxyl group and a phenolic hydroxyl group are not present at the mutually adjacent positions.  
     
     
         10 . The latent catalyst according to    claim 3   , wherein the proton donor represented by HX 5  or HX 6  in which each of X 5  and X 6  is a group formed when a proton donor having at least one proton capable of being liberated out of the molecule has liberated one proton is an aromatic carboxylic acid or a phenolic compound which has at least one substituent selected from the group consisting of carboxyl group and phenolic hydroxyl group and in which two carboxyl groups or a carboxyl group and a phenolic hydroxyl group are not present at the mutually adjacent positions.  
     
     
         11 . The latent catalyst according to    claim 4   , wherein the proton donor which does not participate in the connection of the recurring units is an aromatic carboxylic acid or a phenolic compound which has at least one substituent selected from the group consisting of carboxyl group and phenolic hydroxyl group and in which two carboxyl groups or a carboxyl group and a phenolic hydroxyl group are not present at the mutually adjacent positions.  
     
     
         12 . The latent catalyst according to    claim 2   , wherein the proton donor represented by HY 1 Z 1 Y 2 H or HY 3 Z 2 Y 4 H is an aromatic carboxylic acid or a phenolic compound which has at least two substituents selected from the group consisting of carboxyl group and phenolic hydroxyl group and in which two carboxyl groups or a carboxyl group and a phenolic hydroxyl group are not present at the mutually adjacent positions.  
     
     
         13 . The latent catalyst according to    claim 3   , wherein the proton donor represented by HY 5 Z 3 Y 6 H is an aromatic carboxylic acid or a phenolic compound which has at least two substituents selected from the group consisting of carboxyl group and phenolic hydroxyl group and in which two carboxyl groups or a carboxyl group and a phenolic hydroxyl group are not present at the mutually adjacent positions.  
     
     
         14 . The latent catalyst according to    claim 4   , wherein the proton donor which participates in the connection of the recurring units is an aromatic carboxylic acid or a phenolic compound which has at least two substituents selected from the group consisting of carboxyl group and phenolic hydroxyl group and in which two carboxyl groups or a carboxyl group and a phenolic hydroxyl group are not present at the mutually adjacent positions.  
     
     
         15 . The latent catalyst according to    claim 1   , wherein the proton donor having at least one proton capable of being liberated out of the molecule is a proton donor selected from the group consisting of substituted or unsubstituted benzoic acids, substituted or unsubstituted naphthoic acids, substituted or unsubstituted phenols and substituted or unsubstituted naphthols.  
     
     
         16 . The latent catalyst according to    claim 3   , wherein the proton donor represented by HX 5  or HX 6  in which each of X 5  and X 6  is a group formed when a proton donor having at least one proton capable of being liberated out of the molecule has liberated one proton is a proton donor selected from the group consisting of substituted or unsubstituted benzoic acids, substituted or unsubstituted naphthoic acids, substituted or unsubstituted phenols and substituted or unsubstituted naphthols.  
     
     
         17 . The latent catalyst according to    claim 4   , wherein the proton donor which does not participate in the connection of the recurring units is a proton donor selected from the group consisting of substituted or unsubstituted benzoic acids, substituted or unsubstituted naphthoic acids, substituted or unsubstituted phenols and substituted or unsubstituted naphthols.  
     
     
         18 . The latent catalyst according to    claim 2   , wherein the proton donor represented by HY 1 Z 1 Y 2 H or HY 3 Z 2 Y 4 H is dihydroxybenzene, dihydroxynaphthalene, a bisphenol or a biphenol.  
     
     
         19 . The latent catalyst according to    claim 3   , wherein the proton donor represented by HY 5 Z 3 Y 6 H is dihydroxybenzene, dihydroxynaphthalene, a bisphenol or a biphenol.  
     
     
         20 . The latent catalyst according to    claim 4   , wherein the proton donor which participates in the connection of the recurring units is dihydroxybenzene, dihydroxynaphthalene, a bisphenol or a biphenol.  
     
     
         21 . A thermosetting resin composition comprising 100 parts by weight of a thermosetting resin and 0.4 to 20 parts by weight of a latent catalyst selected from the group consisting of the latent catalysts according to    claims 1    to    4   .  
     
     
         22 . The thermosetting resin composition according to    claim 21   , wherein the thermosetting resin is at least one member selected from the group consisting of epoxy resins and maleimide resins.  
     
     
         23 . An epoxy resin molding material comprising, as the essential components, (A) an epoxy resin, (B) a phenolic resin, (C) the latent catalyst according to any one of    claims 1    to    20    and (D) an inorganic filler, the equivalent ratio between the epoxy group of the total epoxy resin and the phenolic hydroxyl group of the total phenolic resin being 0.5 to 2 and the amount of the inorganic filler (D) compounded being 200 to 2,400 parts by weight per 100 parts by weight of a total amount of the total epoxy resin and the total phenolic resin.  
     
     
         24 . The epoxy resin molding material according to    claim 23   , wherein the epoxy resin (A) is a crystalline epoxy resin having a melting point of 50-150° C.  
     
     
         25 . The epoxy resin molding material according to    claim 24   , wherein the crystalline epoxy resin having a melting point of 50-150° C. is at least one member selected from the group consisting of epoxy resins represented by the general formulas (4) and (5):  
                 
 
       wherein each R 13  is a group or atom selected from the group consisting of hydrogen atom, chain or cyclic alkyl groups having 1 to 6 carbon atoms, phenyl group and halogen atoms and the R 13  groups or atoms may be the same as or different from one another, and  
                 
 
       wherein each R 14  is a group or atom selected from the group consisting of hydrogen atom, chain or cyclic alkyl groups having 1 to 6 carbon atoms, phenyl group and halogen atoms and the R 14  groups or atoms may be the same as or different from one another.  
     
     
         26 . The epoxy resin molding material according to    claim 24   , wherein the crystalline epoxy resin having a melting point of 50-150° C. is a mixture of a stilbene type epoxy resin represented by the general formula (6) and a stilbene type epoxy resin represented by the general formula (7):  
                 
 
       wherein each of R 15  to R 22  represents independently a group or atom selected from the group consisting of hydrogen atom, chain or cyclic alkyl groups having 1 to 6 carbon atoms and halogen atoms, provided that the two aryl groups bonded to the carbon-carbon double bond are different from each other.  
                 
 
       wherein each of R 23  to R 26  represents independently a group or atom selected from the group consisting of hydrogen atom, chain or cyclic alkyl groups having 1 to 6 carbon atoms and halogen atoms, provided that the two aryl groups bonded to the carbon-carbon double bond are the same as each other.  
     
     
         27 . The epoxy resin molding material according to    claim 23   ,    24   ,  25  or  26 , wherein the phenolic resin (B) is a phenolaralkyl resin.  
     
     
         28 . A semiconductor device wherein a semiconductor is encapsulated with an epoxy resin molding material according to    claim 23   ,    24   ,  25 ,  26  or  27 .