Manufacturing method of printed circuit board

Abstract

In a manufacturing method of a printed circuit board comprising a process of coating insulative resin on a surface of a printed circuit board having a blind hole and a process of filling up the insulative resin in the blind hole, the printed circuit board coated with the insulative resin is kept in a low pressure atmosphere of 1.3 to 666 hPa, and then the insulative resin is hardened, so that the insulative resin is filled up in the blind hole appropriately.

What is claimed is:  
     
         1 . A manufacturing method of a printed circuit board comprising steps of: 
 coating insulative resin on a surface of a printed circuit board having a blind hole;    filling up the insulative resin in the blind hole;    keeping the printed circuit board coated with the insulative resin in a low pressure atmosphere of 1.3 to 666 hPa; and    hardening the insulative resin,    wherein said blind hole is filled up with the insulative resin.    
     
     
         2 . The manufacturing method of a printed circuit board in accordance with  claim 1 , wherein said manufacturing method is further characterized by that an insulative resin layer is formed by coating the insulative resin a plurality of times.  
     
     
         3 . The manufacturing method of a printed circuit board in accordance with  claim 2 , wherein said manufacturing method is furthermore characterized by that the printed circuit board coated with the insulative resin is kept in said low pressure atmosphere of 1.3 to 666 hPa only after a first time coating of the insulative resin.  
     
     
         4 . The manufacturing method of a printed circuit board in accordance with  claim 1 , wherein said manufacturing method further comprises a step of adjusting viscosity of the insulative resin to less than 15 Pa . s by heating the insulative resin while keeping in the low pressure atmosphere.