Wiring board, method of manufacturing wiring board, and electronic device

Abstract

A method of manufacturing a wiring board includes steps of: providing a substrate; forming a first wiring layer on the substrate by photolithography; forming a first insulating layer by ink jetting so as to cover a part of the first wiring layer and expose an exposed section of the first wiring layer; and forming a second wiring layer by ink jetting partly over the first wiring layer, with the first insulating layer being between the part of the first wiring layer and a part of the second wiring layer. A wider variety of conductive material and insulating material can be used for forming the wiring layers and the insulating layers on the substrate by ink jetting, while the wiring board has a first wiring layer having high density.

1 . A wiring board comprising: 
 a substrate;    a first wiring layer formed on the substrate by photolithography;    a first insulating layer formed by ink jetting so as to cover at least a part of the first wiring layer; and    a second wiring layer formed by ink jetting partly over the first wiring layer, with the first insulating layer being between the part of the first wiring layer and a part of the second wiring layer.    
   
   
       2 . The wiring board according to  claim 1 , further comprising 
 a second insulating layer formed by ink jetting so as to cover at least a part of the second wiring layer; and    a third wiring layer formed by ink jetting partly over the second wiring layer, with the second insulating layer being between the part of the second wiring layer and a part of the third wiring layer.    
   
   
       3 . The wiring board according to  claim 2 , wherein 
 the first wiring layer has an exposed section that is not covered by the first insulating layer,    the second wiring layer has an exposed section that is not covered by the second insulating layer, and    the third wiring layer has an exposed section that is not covered by the first or the second insulating layer.    
   
   
       4 . The wiring board according to  claim 3 , wherein 
 the second and the third wiring layers are respectively connected to the exposed sections of the first and the second wiring layers and made electrically conductive therewith.    
   
   
       5 . The wiring board according to  claim 2 , further comprising 
 an electronic component mounted on at least one of the exposed sections of the first, second, and the third wiring layers.    
   
   
       6 . The wiring board according to  claim 3 , wherein 
 the exposed section is encircled by the first insulating layer.    
   
   
       7 . The wiring board according to  claim 3 , wherein 
 the substrate is a flexible substrate.    
   
   
       8 . An electro-optical device having the wiring board according to  claim 1 .  
   
   
       9 . An electronic device having the electro-optical device according to  claim 8 .  
   
   
       10 . A method of manufacturing a wiring board, comprising the steps of: 
 providing a substrate;    forming a first wiring layer on the substrate by photolithography;    forming a first insulating layer by ink jetting so as to cover a part of the first wiring layer and expose an exposed section of the first wiring layer; and    forming a second wiring layer by ink jetting partly over the first wiring layer, with the first insulating layer being between the part of the first wiring layer and a part of the second wiring layer.    
   
   
       11 . The method of manufacturing a wiring board according to  claim 10 , further comprising steps of: 
 forming a second insulating layer by ink jetting so as to cover at least a part of the second wiring layer and expose an exposed section of the second wiring layer; and    a third wiring layer formed by ink jetting partly over the second wiring layer, with the second insulating layer being between the part of the second wiring layer and a part of the third wiring layer.    
   
   
       12 . The method of manufacturing a wiring board according to  claim 10 , wherein: 
 in the step of forming the first insulating layer, the exposed section is formed by depositing an insulating material so as to avoid the exposed section, encircling the exposed section with the first insulating layer.    
   
   
       13 . The method of manufacturing a wiring board according to  claim 10 , wherein 
 the step of forming the first insulating layer includes steps of 
 forming a first-tier insulating layer by ink jetting so that an upper surface of the first-tier insulating layer is on the same level with an upper surface of the first wiring layer, and  
 forming a second-tier insulating layer by ink jetting so as to cover at least a part of the first wiring layer and the first-tier insulating layer, so that the second-tier insulating layer is between the second wiring layer and the first wiring layer or the first-tier insulating layer.  
   
   
   
       14 . The method of manufacturing a wiring board according to  claim 13 , further comprising steps of: 
 forming a second insulating layer by ink jetting so as to cover at least a part of the second wiring layer and expose an exposed section of the second wiring layer; and    a third wiring layer formed by ink jetting partly over the second wiring layer, with the second insulating layer being between the part of the second wiring layer and a part of the third wiring layer.    
   
   
       15 . The method of manufacturing a wiring board according to  claim 14 , wherein 
 in the step of forming the third wiring layer, the second and the third wiring layers are respectively connected to the exposed sections of the first and the second wiring layers and made electrically conductive therewith.    
   
   
       16 . The method of manufacturing a wiring board according to  claim 14 , further comprising a step of: 
 mounting an electronic component on at least one of the exposed sections of the first, second, and the third wiring layers.    
   
   
       17 . The method of manufacturing a wiring board according to  claim 13 , wherein 
 in the step of forming the second-tier insulating layer, the second-tier insulating layer is formed only on sides of the exposed section along which the second wiring layer extends across the first-tier insulating layer and the first wiring layer.    
   
   
       18 . An electro-optical device, provided with a wiring board manufactured by the method for manufacturing a wiring board according to  claim 10 .  
   
   
       19 . An electronic device, provided with the electro-optical device according to  claim 18.