Patent Publication Number: US-2015060292-A1

Title: Method for Forming Three Dimensional Circuit

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method for forming a three dimensional circuit, and in particular to the three dimensional circuit is formed by a laser engraving process. 
     BACKGROUND OF THE INVENTION 
     The microlithography process in the traditional semiconductor industry lithography and the associated micro-fabrication technology is based on photolithography etching process. The photolithography imaging resolution and is proportional to the wavelength of the light source, so the resolution has its limits, and these processes are very complex and expensive. 
     In recently, the circuit type of microelectronic circuit which is circuit gradually progress from two dimensional circuit to three dimensional circuit. For the non-flat surface transfer circuit technology is necessary, but for traditional photolithography process, even a slight surface will because the depth of focus is insufficient for transferring the pattern on the non-flat surface even the surface is a slight curve surface. 
     The current three dimensional circuit manufacturing process utilizes the laser engraving to trim a special material substrate with metal component to form a desired circuit pattern. Therefore, the metal plating process is performed in the circuit pattern region which can be called as Laser Direct Structure (LDS) Technology. This technology is flexibility in circuit design, simple steps, but also saves the space and greatly favored. However, the base material price is expensive, and the desired circuit pattern region for the laser engraving has long working hours. 
     SUMMARY OF THE INVENTION 
     According to above drawbacks of the three dimensional circuit manufacturing process, the present invention provides a three dimensional circuit forming method. The steps include that a plastic based is provided. A metal layer is bonded on a surface of the plastic base by a metal coating process. The thickness of the metal layer is thickened by an electroplating process. The metal layer is trimmed by a laser engraving process to form a circuit pattern. 
     Because of the design process for the three dimensional circuit is simple, the required tooling tailor is based on the existing plant equipment, which can be easily imported directly into the production lines, such that the manufacturing cost can be saved. In addition, the laser engraving process can use for the circuit with smaller wire path, and thus the shape of the circuit can be more complex so as to the application range can be enhanced to meet the manufacture of the electronics production trends to slim and light. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof with reference to the drawings, in which: 
         FIG. 1  is a process flow of the three dimensional circuit forming method in accordance with the present invention; 
         FIG. 2  is a perspective view of the metal layer on the plastic base to form a coating film on the plastic base in accordance with the three dimensional circuit forming method of the present invention; 
         FIG. 3  is a perspective view of the thickness of the metal layer is thickened in accordance with the present invention; and 
         FIG. 4  is a perspective view of the circuit pattern is constituted to form a three dimensional circuit three dimensional circuit in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Please refer to  FIG. 1 .  FIG. 1  shows a process flow of the three dimensional circuit forming method of the present invention. The steps of the process flow includes a plastic base is provided as denoted as step S 1 . A metal layer is bonded on a surface of the plastic base to form a coating film on the plastic base as denoted as step S 2 . The thickness of the metal layer is thickened by an electroplating process as denoted as step S 3 . The metal layer is trimmed by a laser engraving process to form a circuit pattern as denoted as step S 4 . 
     Please refer to  FIG. 2  through  FIG. 4 . The material of the plastic base  10  such as a print circuit board or a plastic case which is formed by injection molding, in which the surface of the plastic base  10  can be a flat surface or non-flat surface. The plastic base  10  includes a first surface  11  and a second surface  12  opposite to the first surface  11 . The metal layer  20  is bonded on one surface of the first surface  11  and the second surface  12  to form a coating film  20  on the plastic base  10 . The metal coating process such as sputtering, electroplating, and chemical plating, but it is not limited herein. In addition, the metal layer is a metal foil. The thickness of the metal layer is thickened by an electroplating process, in which the electroplating process such as sputtering, electroplating, or chemical plating. The thickness of the thickened metal layer is range about 5 um and 8 um, and the thickened metal layer can be copper, nickel, gold, or alloy. In addition, the region is designed for the desired circuit pattern that is formed on the metal layer, and the region is defined as an “A” region. Other than the “A” region is defined as a “B” region. Then, the metal layer of the “B” region is removed by a laser engraving process, and the metal layer of the “A” region is remained such that the metal layer of the “A” region can be a three dimensional circuit pattern. 
     The advantage of the three dimensional circuit of the present invention is that the plastic base  10  can be general plastic chassis so as to the acquisition cost of the material can be reduced. The manufacturing process can be simplified due to the metal layer  20  is bonded on the surface of the plastic base  10  by metal coating process to thicken the thickness of the metal layer, such that the effective of the production can be enhanced. In addition, the coating film is trimmed to a circuit pattern  30  by laser engraving with the advantage of the circuit rapid prototyping. 
     According to the abovementioned, the three dimensional circuit of the present invention can reduce costs and improve efficiency effectively. Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.