Method of producing a multi-layered wiring board

Abstract

Method of producing a multi-layered wiring board comprising the steps of subjecting the photosensitive resin to exposure- and development-treatment to form the holes having a predetermined size and shape; depositing and forming the curable resin to the insulating layer having the holes formed therein in such a manner as to bury the holes, and conducting heat-treatment to form the cured thin film of the curable resin on the surface of the insulating layer; and so removing the curable resin as to leave the cured thin film to obtain the via-holes having the reduced opening size by the cured thin film.

What is claimed is:  
     
         1 . A method of producing a multi-layered wiring board comprising the steps of: 
 forming an insulating layer made of a photosensitive resin on a substrate for forming multi-layered wiring, and exposing and developing said insulating layer to form holes having a predetermined shape;    depositing a curable resin onto said insulating layer having said holes formed therein in such a manner as to bury said holes, heating said curable resin to form a cured thin film of said curable resin on the surface of said insulating layer; and    removing said curable resin in such a manner as to leave said cured thin film and to form via-holes having a reduced opening size by said cured thin film.    
     
     
         2 . A method of producing a multi-layered wiring board according to    claim 1   , wherein said photosensitive resin is at least one member selected from the group consisting of an epoxy resin, an epoxy-modified acrylate resin, a cationic polymerization product of an epoxy resin, a phenol resin, a melamine resin, a carboxy-modified epoxy acrylate, and a cinnamate.  
     
     
         3 . A method of producing a multi-layered wiring board according to    claim 1   , wherein said curable resin comprises a water-soluble resin or a water-soluble cross-linking agent.  
     
     
         4 . A method of producing a multi-layered wiring board according to    claim 1   , wherein said curable resin is at least one member selected from the group consisting of polymethylsiliceous siloxane, a melamine resin, an acrylate resin and an epoxy resin.  
     
     
         5 . A method of producing a multi-layered wiring board according to    claim 1   , wherein said curable resin contains rubber particles consisting of a butadiene-acrylonitrile copolymer, and said method further comprises the step of chemically surface-roughening said cured thin film.  
     
     
         6 . A method of producing a multi-layered wiring board according to    claim 2   , wherein said curable resin comprises a water-soluble resin or a water-soluble cross-linking agent.  
     
     
         7 . A method of producing a multi-layered wiring board according to    claim 2   , wherein said curable resin is at least one member selected from the group consisting of polymethylsiliceous siloxane, a melamine resin, an acrylate resin and an epoxy resin.  
     
     
         8 . A method of producing a multi-layered wiring board according to    claim 3   , wherein said curable resin contains particles of calcium carbonate or polybutadiene rubber.  
     
     
         9 . A method of producing a multi-layered wiring board according to    claim 4   , wherein said curable resin contains particles of calcium carbonate or polybutadiene rubber.  
     
     
         10 . A method of producing a multi-layered wiring board including a plurality of stages of via-holes formed by repeating said process steps of    claim 1   , wherein said via-holes of upper stages are so formed as to possess a greater degree of reduction than said via-holes of lower stages.