Polyimide compositions and use thereof in ceramic product defect repair

Abstract

A method to repair ceramic substrates is disclosed using a novel polyimide polymer which has high thermal stability, resistance to fluxes and flux residue cleaning solvents and processes, good mechanical properties, good adhesion to all contacting surfaces with low moisture uptake and good flow properties suitable for repairing chipped ceramic, filling deep trench or vias and writing passivation lines with automated process The polyimide polymer is made by reacting aromatic dianhydride and aromatic diamine monomers with a stoichiometric offset and end capping the resulting polymer when the reaction is completed. The preferred polyimide is made using a molar excess of diamine which is end-capped using an anhydride.

Thus, having described the invention, what is claimed is:  
     
         1 . A method of repairing a ceramic substrate comprising the steps of: 
 providing a ceramic substrate having a defect;    coating the defect region with a polyamic acid composition comprising an aromatic diamine monomer and an aromatic dianhydride monomer where at least one of the monomers is flexible and a stoichiometric excess of one of the monomers is used and subsequently endcapping with an amine or anhydride depending on which monomer was used in excess; and    curing the polyamic acid coating to form a polyimide.    
     
     
         2 . The method of  claim 1  wherein the defect is a surface defect or an internal structure defect  
     
     
         3 . The method of  claim 1  wherein the aromatic diamine is selected from the group consisting of p-Phenylene diamine (p-PDA), 4,4′ Oxydianiline (4,4′ ODA), 3,4′ Oxydianiline (3,4′ ODA), 1,3-Bis(3-Aminophenoxy)benzene (1,3,3′-APB), 2,2′-Bis(Trifluoromethyl)benzidine (B3FB) and mixtures thereof.  
     
     
         4 . The method of  claim 1  wherein the aromatic dianhydride is selected from the group consisting of Pyromellitic Dianhydride (PMDA), Oxydiphthalic Anhydride (ODPA), 3,3′,4,4′-Biphenyl tetracarboxylic acid dianhydride (BPDA) and mixtures thereof.  
     
     
         5 . The method of  claim 1  wherein the polyamic acid composition is applied in multiple applications with curing or partial curing of the applied polyamic composition before the next application.  
     
     
         6 . The method of  claim 5  wherein a flexible chain polyamic acid composition is first applied to the defect, partially cured and then followed by a semi-flexible-planar chain polyamic acid composition, after which the polyamic acid is fully cured.  
     
     
         7 . The method of  claim 1  wherein the polyamic acid composition is in a n-methyl pyrrolidone solvent.  
     
     
         8 . The method of  claim 1  wherein the polyamic acid composition further contains xylene.  
     
     
         9 . The method of  claim 1  wherein the polyamic acid composition further contains a coloring agent.  
     
     
         10 . The method of  claim 1  wherein the polyamic composition further contains an inorganic filler.  
     
     
         11 . The method of  claim 1  wherein the dianhydride monomer is Oxydiphthalic Anhydride (ODPA) and the diamine monomer is 1,3-Bis(3-Aminophenoxy)benzene (1,3,3′-APB), and the diamine monomer is used in stoichiometric excess, and the capping agent is 4,4′-bis(3,4-dicarboxyphenyl)diphenyl sulfide dianhydride (BDSDA).  
     
     
         12 . The method of  claim 1  wherein the dianhydride monomer is Oxydiphthalic Anhydride (ODPA) and the diamine monomer is a mixture of 1,3-Bis(3-Aminophenoxy)benzene (1,3,3′-APB) and 4,4′ Oxydianiline (4,4′ ODA) and 3,4′ Oxydianiline (3,4′ ODA), and the diamine monomer is used in a stoichiometric excess.  
     
     
         13 . The method of  claim 1  wherein the dianhydride monomer is 3,3′,4,4′-Biphenyl tetracarboxylic acid dianhydride (BPDA) and the diamine monomer is a mixture of p-Phenylene diamine (p-PDA) and 2,2′-Bis(Trifluoromethyl)benzidine (B3FB) and mixtures thereof, and the diamine monomer is used in a stoichiometric excess.  
     
     
         14 . A polyamic acid composition for repairing defects in ceramic substrates comprising an aromatic diamine monomer and an aromatic dianhydride monomer where at least one of the monomers is flexible and a stoichiometric excess of one of the monomers is used.  
     
     
         15 . The polyamic acid composition of  claim 14  wherein the aromatic diamine is selected from the group consisting of p-Phenylene diamine (p-PDA), Oxydianiline (4,4′ ODA), 3,4′ Oxydianiline (3,4′ ODA), 1,3-Bis(3-Aminophenoxy)benzene (1,3,3′-APB), 2,2′-Bis(Trifluoromethyl)benzidine (B3FB) and mixtures thereof.  
     
     
         16 . The polyamic acid composition of  claim 14  wherein the aromatic dianhydride is selected from the group consisting of Pyromellitic Dianhydride (PMDA), Oxydiphthalic Anhydride (ODPA), 3,3′,4,4′-Biphenyl tetracarboxylic acid dianhydride (BPDA) and mixtures thereof.  
     
     
         17 . A polyamic acid composition for repairing defects in ceramic substrates comprising an aromatic diamine monomer and an aromatic dianhydride monomer where at least one monomer is semi-flexible-planar and a stoichiometric excess of one of the monomers is used.  
     
     
         18 . The polyamic composition of  claim 14  wherein both the monomers are flexible.  
     
     
         19 . The polyamic composition of  claim 17  wherein the aromatic diamine monomer is selected from the group consisting of 4,4′ Oxydianiline (4,4′ ODA), 3,4′ Oxydianiline (3,4′ ODA), and 1,3-Bis(3-Aminophenoxy)benzene (1,3,3′-APB).  
     
     
         20 . The polyamic composition of  claim 18  wherein the aromatic dianhydride monomer is selected from the group consisting of Oxydiphthalic Anhydride (ODPA) and 3,3′,4,4′-Biphenyl tetracarboxylic acid dianhydride (BPDA).