Method of manufacturing a circuit board by punching

Abstract

A method of manufacturing a circuit board includes: forming a plurality of metal electrodes so as to be separated from each other on a holding sheet by cutting a metal foil held on the holding sheet to remove a portion of the metal foil; forming adhesive layers on surfaces of the plurality of metal electrodes; adhering the adhesive layers to a base material by closely contacting the adhesive layers with the base material; and transcribing the adhesive layers and the plurality of metal electrodes onto the base material by detaching the holding sheet from the plurality of metal electrodes.

What is claimed is: 
     
         1 . A method of punching a metal foil wherein a base material and a metal foil are adhered with a stepwise-curing type adhesive, and a tip of a punching blade is pushed onto the metal foil to cut the metal foil, the method comprising:
 adhering the base material and the metal foil through the stepwise-curing type adhesive;   separating the region which requires the metal foil and the region which does not require the metal foil in the metal foil by pushing a tip of the punching blade onto the metal foil to cut the metal foil in a cross section that is parallel to a thickness direction of the metal foil, along a separating line defined by the tip of the pushed punching blade, and by detaching a predetermined area of the metal foil whose center is the separating line from the stepwise-curing type adhesive;   shredding the region which does not require the metal foil by pushing the tip of the punching blade onto the region which does not require the metal foil to cut the region which does not require the metal foil in a cross section that is parallel to the thickness direction, along a shredding line defined by the tip of the pushed punching blade, and by detaching a predetermined area of the region which does not require the metal foil whose center is the shredding line from the stepwise-curing type adhesive; and   curing the stepwise-curing type adhesive by heating to obtain a stepwise-curing type adhesive layer whose adhesive force is larger than that of the stepwise-curing type adhesive,   wherein after passing through the separating the region which requires the metal foil and the region which does not require the metal foil in the metal foil and passing through the shredding the region which does not require the metal foil, a distance between the shredding line and the separating line in the cross section that is parallel to the thickness direction is set to be equal to or less than a second length.   
     
     
         2 . The method of punching a metal foil according to  claim 1 , further comprising pressing the stepwise-curing type adhesive that, by pressing and deforming the stepwise-curing type adhesive, a space between the stepwise-curing type adhesive and the region which requires the metal foil are filled, the space being formed in the step of separating the region which requires the metal foil and the region which does not require the metal foil in the metal foil. 
     
     
         3 . The method of punching a metal foil according to  claim 1 , wherein an adhesive force in the 180° detachment test defined by J IS K6854-2 is:
 0.05 N/cm or more and 1.0 N/cm or less for the stepwise-curing type adhesive, and 
 3.0 N/cm or more for the stepwise-curing type adhesive layer. 
 
     
     
         4 . The method of punching a metal foil according to  claim 1 , wherein a surface of the stepwise-curing type adhesive layer that is obtained by curing the stepwise-curing type adhesive does not have tackiness. 
     
     
         5 . The method of punching a metal foil according to  claim 1 , further comprising preliminary determining a detachment length, wherein the detachment length is a length of when the metal foil is detached from the stepwise-curing type adhesive by setting a base line as a center, the base line being defined by a tip of the pushed punching blade when the tip of the punching blade is pushed onto the metal foil, the metal foil being adhered to the base material through the stepwise-curing type adhesive, in a cross section that is parallel to a thickness direction of the metal foil, wherein a value twice of the detachment length is used as the second length. 
     
     
         6 . The method of punching a metal foil according to  claim 5 , wherein a minimum value of a distance between the separating lines adjacent to each other is larger than the detachment length at least in a portion of the region which requires the metal foil. 
     
     
         7 . The method of punching a metal foil according to  claim 1 , wherein the tip of the punching blade is formed to have an acute angle. 
     
     
         8 . The method of punching a metal foil according to  claim 1 , wherein the separating the region which requires the metal foil and the region which does not require the metal foil in the metal foil and the shredding the region which does not require the metal foil are performed at the same time. 
     
     
         9 . A metal foil pattern laminate manufactured by the method of punching a metal foil according to  claim 1 . 
     
     
         10 . A circuit board comprising:
 a base material;   a plurality of adhesive layers formed on a surface of the base material, the plurality of adhesive layers being separated from each other; and   a metal electrode formed on each of the adhesive layers.   
     
     
         11 . The circuit board according to  claim 10 , wherein an outer surface of each of the metal electrodes slopes outward from a surface of each of the metal electrodes to the adhesive layer, and a protruding portion that protrudes to the adhesive layer is formed on an end portion of the outer surface. 
     
     
         12 . A solar cell module comprising:
 the circuit board according to  claim 10 ; and   a solar cell electrically connected onto the circuit board.