Patent Publication Number: US-2007102103-A1

Title: Manufacturing method for printing circuit

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a manufacturing method for a printing circuit, and more particularly to a manufacturing method for a line in a printing circuit such as a line of an induction current for a radio frequency identification (RFID) and a line of a flexible printed circuit board (FPC).  
      2. Description of Related Art  
      One type of a general induction circuit for RFID is formed by winding a copper wire into a coil; the deficit thereof is that the outlook thereof must be manufactured to be cylinder-typed. Accordingly, the variation thereof is few, and the product cost is rather high comparing to other manufacturing processes. Another type thereof is formed by an etching method to stick; the manufacturing manner thereof is to electroplate a layer of metal on a plastic film, and after a mask is printed on a part of the surface of the metal film on which a line is desired to maintain, a unnecessary part thereof is etched to form an induction line. The deficit thereof is that the manufacturing processes are minute and complicated and rather not of environmental consciousness. Still another type is formed by a printing method; the manufacturing manner thereof is to add metal (e.g. silver and copper) powder into printing ink to cause the printing ink to be electrically conductive and then use it to print a necessary line directly on a plastic film. A merit thereof is that the manufacturing processes are simple and the working is convenient, but the deficit is that the price of the printing ink is too high.  
      A general copper foil used for manufacturing a flexible printing circuit board can be divided into a rolled anneal copper foil and an electro-deposited copper foil. Manufacturing a rolled anneal copper foil needs using a considerable expensive facility and passing through many copper plate rolling steps; the manufacturing processes are complex and the production cost is quite high. Manufacturing an electro-deposited copper foil is also complex and causes environmental pollution. If the factors of the environmental pollution want to be overcome, more rear stage processing facilities must be invested in; the production cost is considerably consumed.  
      Taiwan Patent No. 556,453 discloses a printing circuit board with an inlay-typed outer layer wire and the manufacturing thereof, it is characterized in that the outer layer wire is inlayed in a dielectric layer and stuck therewith on three faces; the manufacturing method thereof concludes: (a) providing a release type moldboard; (b) forming a metal layer on a surface of the separated type moldboard; (c) forming a photoresist layer on the metal layer; (d) forming a predetermined circuit pattern on the photoresist layer by means of exposure developing to expose a part of the metal layer out; (e) processing metallization to from a wiring layer on the exposed metal layer; (f) removing the photoresist layer to form the wiring layer with a predetermined circuit pattern on the separate moldboard; (g) pressing the separate type moldboard and a dielectric layer together to cause the wiring layer to be combined with the dielectric layer together closely and inlayer in the dielectric layer, and the metal layer is then combined with the surface of the dielectric layer; (h) removing the separate type moldboard; and (i) removing the metal layer on the dielectric layer.  
      The manufacturing processes of the above-mentioned Taiwan Patent are also very complex, and the production time and cost are very much consumed.  
     SUMMARY OF THE INVENTION  
      For simplifying the manufacturing processes for a line in a general printing circuit and saving the production cost, the present invention is proposed.  
      The main object of the present invention is to provide a printing circuit, capable of simplifying the manufacturing processes and enhancing the production efficiency.  
      Another object of the present invention is to provide a manufacturing method for a printing circuit, the production cost thereof is low, it is unnecessary to use materials not to harm environment so that the manufacturing processes are more environmentally conscious.  
      Still another object of the present invention is to provide a manufacturing method for a printing circuit, capable of adjusting a printing line accompanying the need. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention can be more fully understood by reference to the following description and accompanying drawings, in which:  
       FIGS. 1A  to  1 G are schematic views, showing manufacturing processes for a printing circuit of a preferred embodiment according to the present invention;  
       FIG. 2  is a schematic view, showing an induction antenna line with radio frequency identification on a carrier; and  
       FIG. 3  is a schematic view, showing a flexible printing circuit board with a line thereon.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Please refer to  FIGS. 1A  to  1 G.  FIGS. 1A  to  1 G are schematic views show a manufacturing method for a printing circuit of a preferred embodiment according to the present invention. It comprises the following steps: 
          (1) spreading a release layer  12  with an effect of release on a plastic film  11 , as  FIG. 11A  shows, thereafter, electroplating a metal layer  13  on a surface of the release layer  12  by utilizing a vacuum film-electroplating technology to form a mother film  10 , as  FIG. 1B  shows;     (2) electroplating a metal layer  13 , increasing the thickness of the metal layer  13 , as  FIG. 1C ;     (3) utilizing an adhesive as a printing material to print a line with a predetermined pattern on a carrier  21  on which a printing circuit is to be fabricated, by printing the adhesive onto the carrier  21  to form an adhesive layer  22 ; the adhesive layer  22  forms a shape of the line with a predetermined pattern, as  FIG. 1D  shows;     (4) covering the metal layer  13  of the mother film on the carrier  21  to cause the metal layer  13  to be stuck on the carrier  21 , as  FIG. 1E  shows; and solidifying the adhesive layer  22  to cause the carrier  21  to be stuck with the metal layer  13 ;     (5) separating the mother film with the carrier  21 , a part of the carrier  21  with the adhesive then pulls and attaches itself with the metal film  13 , and another part without the adhesive does not pull and attach itself with the metal film  13  such that a metal line  131  with a predetermined pattern is formed on the carrier  21 , as  FIG. 1F  shows. and     (6) Spreading a layer of protection layer  23  on the metal line  131  of the carrier  21 , as  FIG. 1G  shows.        

      In the steps mentioned above, the plastic film  11  can be a polyethylene (PE) film, a polycarbonate (PC) film or a polyethylene tetraphthate (PET) film; the material of the release layer  12  can be a silicon base resin or other material that is not firmly bounded with metal; the material of the metal layer  13  can be silver, copper or aluminum; the material of the carrier  21  can be a paper, a plastic film or flexible printing circuit board; the material of the adhesive layer  22  can be ultraviolet (UV) resin or adhesive; and the material of the protection layer  23  can be a series of acrylic or PU.  
      In Step ( 4 ), if the adhesive layer  22  is a UV resin, the adhesive layer  22  is directly illuminated with Ultraviolet light to cause it to be solidified; if it is another kind of adhesive, it is then dried with a heat source to cause it to be solidified.  
      In Step ( 6 ), the protection layer  23  is spread after the fabrication of the metal line  131  is complete, to prevent the electric characteristics of the metal line  31  from being changed owing to oxidation.  
      The fabricated metal line  131  according to the present invention can be a general inductive antenna with RFID. Because the metal line  131  used as an inductive antenna only receives or transmits signals, the power of transmission electric power is not large, the electroplating process in Step ( 2 ) is not needed. But, when the metal line  131  is used as a line on a flexible circuit board, because the electric power transmitted by the is larger, the thicker metal line  131  is needed, so that the electroplating process in Step ( 2 ) is needed to increase the thickness of the metal line  131  to increase the capability of the electric power transmission of the metal line  131 .  
      The present invention is mainly to use an adhesive as a printing material to print a line pattern of a printing circuit on a carrier by means of printing, and then cause an adhesive to stick with a mother film with a release metal to allow a part of the carrier with the adhesive to pull and attach itself with a metal film, and another part without the adhesive does not pull and attach itself with the metal film such that a metal line is formed on the carrier. For example, an induction antenna line  32  with RFID is formed on a carrier  31  such as a paper or plastic film, as  FIG. 3  shows; or a line  42  is formed on a carrier  41  such as a flexible printing circuit board, as  FIG. 3  shows.  
      A general printing method is utilized to form a line pattern according to the present invention, the manufacturing processes can be simplified, the fabrication of a line is very fast, the production efficiency can be enhanced and the production cost is low. The printed line pattern is easier to be revised according to the present invention, the printing line can be quickly adjusted accompanying the need, and the material harmful to the environment need not be used, the environmental pollution is not caused so that it is rather environmentally conscious.  
      Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.