Method of manufacturing printed circuit board for optical waveguide

Abstract

A method of manufacturing a printed circuit board for an optical waveguide includes forming an insulation layer having a through hole on a substrate; forming a lower clad layer on a bottom of the through hole; forming a core part on the lower clad layer; and forming an upper clad layer covering the core part on the lower clad layer and the core part.

What is claimed is: 
     
         1 . A method of manufacturing a printed circuit board for an optical waveguide, comprising:
 forming an insulation layer having a through hole on a substrate;   forming a lower clad layer on a bottom of the through hole;   forming a core part on the lower clad layer; and   forming an upper clad layer covering the core part on the lower clad layer and the core part.   
     
     
         2 . The method according to  claim 1 , wherein the forming of the insulation layer having the through hole comprises:
 forming an insulation layer on a substrate; and   forming a through hole in the insulation layer through an exposure/development process or a laser drilling process.   
     
     
         3 . The method according to  claim 1 , wherein the forming of the lower clad layer comprises:
 applying a liquid lower clad material on a bottom of the through hole;   flattening the applied lower clad material by placing a transparent release film thereon; and   curing the flattened lower clad material by applying ultraviolet rays or heat thereto to form the lower clad layer on a bottom of the through hole.   
     
     
         4 . The method according to  claim 1 , wherein the forming of the core part comprises:
 applying a liquid core material on the lower clad layer formed in the through hole;   flattening the applied core material by placing a transparent release film thereon;   selectively exposing the flattened core material using a pattern mask; and   removing the transparent release film and then developing the exposed core material to form the core part.   
     
     
         5 . The method according to  claim 1 , wherein the forming of the core part comprises:
 applying a liquid core material on the lower clad layer formed in the through hole;   curing the applied core material by applying light or heat thereto; and   patterning the cured core material using a laser to form the core part.   
     
     
         6 . The method according to  claim 1 , wherein the forming of the upper clad layer is performed through a process of applying an upper clad material on the lower clad layer and the core part and then curing the applied upper clad material or a process of placing an upper clad film on the lower clad layer and the core part. 
     
     
         7 . The method according to  claim 1 , wherein the substrate includes a polyimide layer and a metal layer formed beneath the polyimide layer, and
 wherein the method further comprises:   patterning the metal layer to form circuit patterns after the forming of the upper clad layer.   
     
     
         8 . A method of manufacturing a printed circuit board for an optical waveguide, comprising:
 forming a lower insulation layer having a lower through hole on a substrate;   forming a lower clad layer in the lower through hole;   forming an upper insulation layer having an upper through hole connected with the lower through hole to thus form a single through hole on the lower insulation layer;   forming core part on the lower clad layer; and   forming an upper clad layer covering the core part on the lower clad layer and the core part.   
     
     
         9 . The method according to  claim 8 , wherein the forming of the lower clad layer comprises:
 applying a liquid lower clad material in the lower through hole;   flattening the applied lower clad material by placing a transparent release film thereon; and   curing the flattened lower clad material by applying ultraviolet rays or heat thereto to form the lower clad layer in the lower through hole.