Metalization of flexible polymer sheets

Abstract

A conductive grid formation system, apparatus, and related methods may include a drum having a conductive surface, an insulation layer coating said surface, and a grid pattern formed in the insulation layer to expose portions of the conductive surface. The drum surface may be rotated into and out of a chemical bath, such that a metallic grid is electrodeposited in the exposed portions of the conductive surface. A polymer sheet may be laminated to the surface of the drum and then removed, such that the metallic grid attaches to the polymer sheet and is removed with the polymer sheet. Heat, pressure, and/or adhesive may be utilized in various steps of the process, to facilitate preferential adhesion of the metallic grid to the polymer sheet.

What is claimed is: 
     
         1 . A method of manufacturing a flexible circuit, comprising:
 impinging a laser on a surface of an electrically conductive cylinder to create a pattern of microscopic fissures on the surface;   applying an electrically insulating coating to the cylinder, wherein the coating is patterned to expose portions of the surface of the cylinder in a pattern corresponding to an electrical circuit;   immersing the cylinder at least partially into a metal-containing solution;   electrodepositing metal from the metal-containing solution onto the exposed portions of the surface of the cylinder;   rotating the cylinder until the electrodeposited metal comes into contact with a substrate contacting a portion of the cylinder; and   separating the substrate from the cylinder with the electrodeposited metal attached to the substrate in the pattern corresponding to the electrical circuit.   
     
     
         2 . The method of  claim 1 , wherein the substrate is flexible and the electrical circuit is a flexible circuit. 
     
     
         3 . The method of  claim 2 , wherein the flexible circuit is a radio frequency identification tag (RFID tag). 
     
     
         4 . The method of  claim 1 , wherein the substrate is a flexible polymer sheet. 
     
     
         5 . The method of  claim 1 , further comprising patterning the electrically insulating coating with a laser. 
     
     
         6 . The method of  claim 1 , wherein the electrically insulating coating is formed from a synthetic fluoropolymer. 
     
     
         7 . The method of  claim 1 , further comprising applying a release layer to the exposed portions of the surface of the cylinder. 
     
     
         8 . A method of manufacturing an electrical circuit, comprising:
 immersing a cylinder at least partially into a metal-containing solution, wherein the cylinder is electrically conductive and includes (i) a plurality of microscopic fissures formed on an outer surface and (ii) an electrically insulating coating adhered to the outer surface, and wherein the coating is patterned to expose portions of the outer surface in a pattern corresponding to an electrical circuit to be formed;   electrodepositing metal from the metal-containing solution onto the exposed portions of the outer surface of the cylinder;   rotating the cylinder until the electrodeposited metal comes into contact with a flexible substrate wrapped around a portion of the cylinder; and   separating the substrate from the cylinder with the electrodeposited metal attached to the substrate in the pattern corresponding to the electrical circuit.   
     
     
         9 . The method of  claim 8 , wherein the electrical circuit to be formed is a flexible circuit. 
     
     
         10 . The method of  claim 9 , wherein the pattern corresponds to a radio frequency identification tag (RFID tag). 
     
     
         11 . The method of  claim 8 , wherein the substrate is a flexible polymer sheet. 
     
     
         12 . The method of  claim 8 , wherein the electrically insulating coating is formed from a synthetic fluoropolymer. 
     
     
         13 . The method of  claim 12 , wherein the synthetic fluoropolymer coating is formed from a material chosen from the set consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP) and a parylene polymer. 
     
     
         14 . The method of  claim 8 , further comprising applying a release layer to the exposed portions of the surface of the cylinder. 
     
     
         15 . A method of manufacturing an electrical circuit, comprising:
 providing an electrically conductive cylinder having a plurality of microscopic fissures formed on an outer surface and an electrically insulating coating applied over the outer surface, wherein the coating is patterned to expose portions of the outer surface in a pattern corresponding to an electrical circuit to be formed;   immersing the cylinder at least partially into a metal-containing solution;   electrodepositing metal from the metal-containing solution onto the exposed portions of the outer surface of the cylinder;   rotating the cylinder until the electrodeposited metal comes into contact with a substrate; and   separating the substrate from the cylinder with the electrodeposited metal attached to the substrate in the pattern corresponding to the electrical circuit.   
     
     
         16 . The method of  claim 15 , wherein providing the cylinder includes forming the microscopic fissures by scanning a pulsed laser over the outer surface of the cylinder. 
     
     
         17 . The method of  claim 15 , further comprising compressing the substrate against the cylinder to increase adhesion between the substrate and the electrodeposited metal, before separating the substrate from the cylinder. 
     
     
         18 . The method of  claim 15 , wherein the substrate is a flexible polymer sheet including a heat activated adhesive disposed on one side, and further comprising heating the polymer sheet to activate the adhesive and increase adhesion between the polymer sheet and the electrodeposited metal, before separating the polymer sheet from the cylinder. 
     
     
         19 . The method of  claim 18 , further comprising cooling the polymer sheet to reduce adhesion of the polymer sheet to the cylinder, before separating the sheet from the cylinder. 
     
     
         20 . The method of  claim 15 , wherein the pattern corresponds to a radio frequency identification tag (RFID tag).