Inner substrate for manufacturing multilayer printed circuit boards

Abstract

An exemplary inner substrate for manufacturing multilayer printed circuit boards is provided. The inner substrate has a number of substrate units and a number of transverse folding portions alternately arranged along a longitudinal direction of the inner substrate. Each of the substrate units is configured for forming a unitary printed circuit board. Each of the folding portions is interconnected between neighboring substrate units. Each of the folding portions defines at least one line of weakness perpendicular to the longitudinal direction of the inner substrate for facilitating folding and unfolding the neighboring substrate units to each other.

1 . An inner substrate for manufacturing multilayer printed circuit boards, the inner substrate comprising:
 a plurality of substrate units and a plurality of transverse folding portions alternately arranged along a longitudinal direction of the inner substrate, each of the substrate units being configured for forming a unitary multilayer printed circuit board, each of the folding portions being interconnected between two neighboring substrate units, each of the folding portions defining at least one line of weakness perpendicular to the longitudinal direction of the inner substrate for facilitating folding and unfolding the inner substrate.   
   
   
       2 . The inner substrate of  claim 1 , wherein the at least one line of weakness includes a first line and a second line parallel to the first line, each of the folding portions comprising a plurality of first through-holes aligned in the first line and a plurality of second through-holes aligned in the second line. 
   
   
       3 . The inner substrate of  claim 2 , wherein the inner substrate includes an insulating base film and two electrically conductive layers formed on two opposite sides of the insulating base film, and the first through-holes and the second through-holes penetrate through the insulating base film and the electrically conductive layers. 
   
   
       4 . The inner substrate of  claim 2 , wherein the distance between the first line and the second line of each folding portion is equal. 
   
   
       5 . The inner substrate of  claim 2 , wherein the distance between the first line and the second line of one folding portion is different from that of another folding portion. 
   
   
       6 . The inner substrate of  claim 1 , wherein each of the folding portions defines at least one groove in at least one side thereof along the at least one line of weakness. 
   
   
       7 . The inner substrate of  claim 6 , wherein the inner substrate includes an insulating base film and two electrically conductive layers formed on two opposite sides of the insulating base film, and a thickness of the at least one groove is larger than a thickness of one of the electrically conductive layers and less than a sum of thicknesses of the insulating base film and one of the electrically conductive layers. 
   
   
       8 . The inner substrate of  claim 1 , wherein each of the folding portions defines at least one groove in at each of the two opposite sides of the inner substrate along the at least one line of weakness. 
   
   
       9 . The inner substrate of  claim 1 , wherein the at least one line of weakness includes a first line and a second line, each of the folding portions comprising a first groove in at least one side thereof along the first line and a second groove in at least one side thereof along the second line parallel to the first line. 
   
   
       10 . The inner substrate of  claim 8 , wherein the distance between the first line and the second line of each folding portion is equal. 
   
   
       11 . The inner substrate of  claim 8 , wherein the distance between the first line and the second line of one folding portion is different from that of another folding portion. 
   
   
       12 . The inner substrate of  claim 1 , wherein the at least one line of weakness includes a first line and a second line parallel to the first line, each of the folding portions comprising a first groove respectively at two opposite sides of the inner substrate along the first line and a second groove respectively at two opposite sides of the inner substrate along the second line. 
   
   
       13 . The inner substrate of  claim 1 , wherein each of the substrate units includes at least one insulating layer and at least one electrically conductive layer formed on the dielectric layer.