Abstract:
An embodiment of the invention provides a method for forming an antenna which includes: providing a workpiece having a surface; providing a compression head including a main body, a soft rubber head disposed on the main body, and at least a through-hole, wherein the through-hole penetrates through the main body and the soft rubber head; adsorbing and fixing a conducting film on the soft rubber head through the through-hole; moving the compression head against the surface of the workpiece to press the conducting film onto the surface of the workpiece; removing the compression head; and patterning the conducting film.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority of Taiwan Patent Application No. 101118917, filed on May 28, 2012, the entirety of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an antenna, and in particular, relates to a method for forming an antenna and a compression head used in the forming of the antenna. 
         [0004]    2. Description of the Related Art 
         [0005]    There are many limitations when conventional metallization technologies are applied to form antennas. Because the fabrication process is complicated or the electrical impedance is too high, the variety in design of antennas is limited and the efficiency thereof is low. 
         [0006]    Recently, because the space and the environmental condition are limited, the antennas of many mobile devices are designed to be on a curved surface or planes which are not coplanar with each other. The conventional technologies such as a printing process and a thermocompression process are only suitable for the application of 2D planar designs. For 3D transfer printing technology, it can only he applied on a curved surface having a high curvature or locations having no interference effect due to interference limitations. In addition, by using a sputtering process or an evaporation process, it is easy for a portion of the formed metal layer to have insufficient thickness due to fabrication process limitations, such that resistance is too high, causing the antenna to have low efficiency. 
         [0007]    In order to reduce and/or resolve the problems mentioned above, it is desired to have an improved fabrication process for forming an antenna. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    An embodiment of the invention provides a method for forming an antenna, which includes: providing a workpiece, wherein the workpiece has a surface; providing a compression head, wherein the compression head comprises a main body, a soft rubber head disposed on the main body, and at least a through hole, wherein the through hole passes through the main body and the soft rubber head; adsorbing and fixing a conductive film on the soft rubber head through the through hole; pressing the compression head against the surface of the workpiece to press the conductive film to the surface of the workpiece; removing the compression head; and patterning the conductive film. 
         [0009]    An embodiment of the invention provides a method for forming an antenna, which includes: providing a workpiece, wherein the workpiece has a surface; providing a compression head, wherein the compression head comprises a main body, a soft rubber head disposed on the main body, and at least a through hole, wherein the through hole passes through the main body and the soft rubber head; forming a patterned conductive layer on a release film; adsorbing and fixing the release film on the soft rubber head through the through hole; pressing the compression head against the surface of the workpiece, such that the patterned conductive layer on the release film is detached from the release film and sticks to the surface of the workpiece; and removing the compression head and the release film. 
         [0010]    An embodiment of the invention provides a method for forming an antenna, which includes: providing a workpiece, wherein the workpiece has a surface; forming a conductive layer on the surface of the workpiece; providing a compression head, wherein the compression head comprises a main body, a soft rubber head disposed on the main body, and at least a through hole, wherein the through hole passes through the main body and the soft rubber head; forming a patterned mask layer on a release film; adsorbing and fixing the release film on the soft rubber head through the through hole; pressing the compression head against the surface of the workpiece, such that the patterned mask layer on the release film is detached from the release film and sticks to the conductive layer on the surface of the workpiece; removing the compression head and the release film; and performing an etching process to remove a portion of the conductive layer so as to pattern the conductive layer by using the patterned mask layer. 
         [0011]    An embodiment of the invention provides a compression head, which includes: a main body; a soft rubber head disposed on the main body; and at least a through hole passing through the main body and the soft rubber head. 
         [0012]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0014]      FIG. 1A  is a cross-sectional view of a compression head according to an embodiment of the present invention; 
           [0015]      FIG. 1B  is a perspective view of a compression head according to an embodiment of the present invention; 
           [0016]      FIGS. 2A-2D  are cross-sectional views of a manufacturing process of an antenna according to an embodiment of the present invention; 
           [0017]      FIGS. 3A-3D  are cross-sectional views of a manufacturing process of an antenna according to an embodiment of the present invention; and 
           [0018]      FIGS. 4A-4C  are cross-sectional views of a manufacturing process of an antenna according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0020]    It is understood, that the following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numbers and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Furthermore, descriptions of a first layer “on,” “overlying,” (and like descriptions) a second layer, include embodiments where the first and second layers are in direct contact and those where one or more layers are interposing the first and second layers. 
         [0021]      FIG. 1A  is a cross-sectional view of a compression head  10  according to an embodiment of the present invention.  FIG. 1B  is a perspective view of the compression head  10  of  FIG. 1A . The compression head  10  of the present embodiment may be, for example, used to form antennas. As shown in  FIGS. 1A-1B , the compression head  10  may include a main body  100 , a soft rubber head  102  disposed on the main body  100 , and at least one through hole  104 . The through hole  104  passes through the main body  100  and the soft rubber head  102 . In one embodiment, the through hole  104  may be connected to a vacuum system or a gas extraction system (not shown). Thus, the vacuum system or the gas extraction system may apply a suction force at the surface of the soft rubber head  102  through the through hole  104 . In one embodiment, a plurality of through holes  104  pass through the main body  100  and the soft rubber head  102 . Furthermore, the compression head  10  may include a heating apparatus (not shown). For example, the main body  100  may be connected to a fire brick or other suitable heat conduction devices to raise the temperature of the soft rubber head  102 . In one embodiment, the soft rubber head  102  may include, but is not limited to, silicone, Teflon, or the combinations thereof. 
         [0022]    In one embodiment, the compression head  10  may be used to form a conductive pattern. For example, the compression head  10  may be used to, but is not limited to, form a suitable conductive pattern on the surface of the workpiece, so as to form antennas. 
         [0023]      FIGS. 2A-2D  are cross-sectional views of a manufacturing process of an antenna according to an embodiment of the present invention, wherein same or similar reference numbers are used to designate same or similar elements. 
         [0024]    As shown in  FIG. 2A , a workpiece  200  is provided. The workpiece  200  may be, for example, a casing of a cell phone. In one embodiment, the workpiece  200  may be optionally fixed in a fixing device  202  to expose a surface of the workpiece  200 . The surface of the workpiece  200  may be a curved surface, such as an inner surface of the casing of the cell phone. Alternatively, the surface of the workpiece  200  may be a convexo-concave surface or an irregular surface. 
         [0025]    In one embodiment, the compression head  10 , similar to that in  FIGS. 1A-1B , is provided, wherein the compression head  10  includes the main body  100 , the soft rubber head  102 , and the through holes (not shown). Then, the conductive film  206  is adsorbed and fixed on the soft rubber head  102  through the through holes of the compression head  10 . The conductive film  206  may include copper foils, aluminum foils, gold foils, tin foils, or the combinations thereof. In one embodiment, an adhesive layer  204  may be optionally disposed on the lower surface of the conductive film  206 , such that the conductive film  206  may be stuck on the surface of the workpiece  200  through the adhesive layer  204  in the subsequent process. 
         [0026]    Then, the compression head  10  is pressed against the surface of the workpiece  200  to press the conductive film  206  to the surface of the workpiece  200 . The soft rubber head  102  of the compression head  10  has elasticity or flexibility, so the stress applied on the surface of the workpiece  200  may be evenly distributed when the conductive film  206  is pressed to the surface of the workpiece  200 , which can effectively prevent the fracture and/or the deformation of the workpiece  200 . In one embodiment, the workpiece  200  includes brittle materials, such as glass or ceramic materials, etc. The compression head of the present embodiment is adopted to form the conductive pattern on the workpiece, which can effectively prevent the fracture and/or the deformation of the workpiece. 
         [0027]    In one embodiment, the conductive film  206  can directly contact the surface of the workpiece  200 . In another embodiment, the adhesive layer  204  is disposed on the lower surface of the conductive film  206 . In this case, the adhesive layer  204  is sandwiched between the conductive film  206  and the surface of the workpiece  200 . In one embodiment, the temperature of the compression head  10  may be increased when the conductive film  206  is pressed to the surface of the workpiece  200 . For example, the compression head  10  may be heated, or the temperature of the processing environment may be increased. Then, the compression head  10  may be removed, as shown in  FIG. 2B . 
         [0028]    Then, the conductive film  206  is patterned to form an antenna. In one embodiment, as shown in  FIG. 2C , a photoresist layer  208  may be formed on an upper surface of the conductive film  206 . In one embodiment, the photoresist layer  208  is formed on the upper surface of the conductive film  206  by a spray coating process, a spin coating process, or other suitable processes. In another embodiment, the photoresist layer  208  (e.g. a dry film or a circuit protection glue) is adsorbed and fixed on the soft rubber head  102  through the through holes of the compression head  10 , which is similar to the method shown in  FIG. 2A . Then, the compression head  10  is pressed against the surface of the workpiece  200  to press the photoresist layer  208  to the upper surface of the conductive film  206 . Then, a photolithography process is performed to the photoresist layer  208  to pattern the photoresist layer  208  so as to form a patterned photoresist layer. In another embodiment, a laser engraving process may be performed to pattern the photoresist layer  208  on the upper surface of the conductive film  206 . The patterned photoresist layer may have openings exposing a portion of the conductive film  206 . 
         [0029]    Then, the portion of the conductive film  206  which is exposed is removed to pattern the conductive film  206  so as to form a patterned conductive film  206   a  as shown in  FIG. 2D  by using the patterned photoresist layer as a mask. Then, the workpiece  200  may be removed from the fixing device  202  to finish forming an antenna. 
         [0030]    In the embodiment of  FIGS. 2A-2D , the conductive film  206  is patterned after the conductive film  206  is adsorbed and fixed on the soft rubber head  102  through the through holes of the compression head  10 , but the invention is not limited thereto. In another embodiment, the conductive film  206  is patterned before the conductive film  206  is adsorbed and fixed on the soft rubber head  102  through the through holes of the compression head  10 . For example, the adhesive layer  204  and the conductive film  206  are disposed on a release film (not shown), and the conductive film  206  is patterned, wherein the adhesive layer  204  is an optional element. Then, the adhesive layer  204  and the conductive film  206  are removed from the release film, and the patterned conductive film is adsorbed and fixed and is pressed to the workpiece  200  by the compression head  10 , which is similar to the method shown in  FIGS. 2A-2B . 
         [0031]      FIGS. 3A-3D  are cross-sectional views of a manufacturing process of an antenna according to an embodiment of the present invention, wherein same or similar reference numbers are used to designate same or similar elements. 
         [0032]    As shown in  FIG. 3A , a patterned conductive layer  306   a  is formed on a release film  300 . In one embodiment, the conductive layer  306   a  may include a patterned conductive ink. For example, a conductive ink is transferred to the release film  300  to form the patterned conductive layer  306   a  by performing a printing process and using a transfer film with a specific opening pattern (not shown). 
         [0033]    As shown in  FIG. 3B , the compression head  10 , similar to that of  FIGS. 1A-1B , is provided, and the compression head  10  includes the main body  100 , the soft rubber head  102 , and the through holes (not shown). Then, the release film  300  is adsorbed and fixed on the soft rubber head  102  through the through holes of the compression head  10 . 
         [0034]    Then, the compression head  10  is pressed against the surface of the workpiece  200 , such that a portion of (or a whole of) the patterned conductive layer  306   a  on the release film  300  is detached from the release film  300  and sticks on the surface of the workpiece  200 . In one embodiment, the temperature of the compression head  10  may be increased when at least a portion of the conductive layer  306   a  is pressed to the surface of the workpiece  200 . For example, the compression head  10  may be heated, or the temperature of the processing environment may be increased. Then, the compression head  10  and the release film  300  may be removed to finish forming an antenna, as shown in  FIG. 3C . 
         [0035]    In one embodiment, a conductive material may be optionally deposited on the conductive layer  306   a  to increase the thickness of the conductive layer  306   a.  For example, in one embodiment, an electroplating process and/or a chemical plating process may be performed to deposit a conductive material on the conductive layer  306   a  on the surface of the workpiece  200  so as to form the conductive layer  306   b,  as shown in  FIG. 3D . Then, the workpiece  200  is removed from the fixing device  202  to finish forming an antenna. 
         [0036]      FIGS. 4A-4C  are cross-sectional views of a manufacturing process of an antenna according to an embodiment of the present invention, wherein same or similar reference numbers are used to designate same or similar elements. 
         [0037]    As shown in  FIG. 4A , a workpiece  200  is provided. The workpiece  200  may be, for example, a casing of a cell phone. In one embodiment, the workpiece  200  may be optionally fixed in a fixing device  202  to expose a surface of the workpiece  200  (e.g. an inner surface of the workpiece  200 ). Then, a conductive layer  406  is formed on the surface of the workpiece  200 . For example, a sputtering process or a vapor deposition process may be performed to form the conductive layer  406  on the surface of the workpiece  200 . In one embodiment, the conductive layer  406  may substantially cover the whole of the surface of the workpiece  200 . 
         [0038]    In one embodiment, a patterned mask layer  408  may be optionally formed on the release film  400 . In one embodiment, the mask layer  408  may include a circuit protection ink or a photoresist material. For example, a circuit protection ink is transferred to the release film  400  to form the patterned mask layer  408  by performing a printing process and using a transfer film with a specific opening pattern (not shown). Alternatively, a photoresist layer may be formed on the release film  400 , and the photoresist layer is patterned to form the patterned mask layer  408  by a photolithography process. 
         [0039]    Then, the compression head  10 , similar to that of  FIGS. 1A-1B , is provided, and the compression head  10  includes the main body  100 , the soft rubber head  102 , and the through holes (not shown). Then, the release film  400  is adsorbed and fixed on the soft rubber head  102  through the through holes of the compression head  10 . 
         [0040]    Then, the compression head  10  is pressed against the surface of the workpiece  200 , such that a portion of (or a whole of) the patterned mask layer  408  on the release film  400  is detached from le release film  400  and sticks on the conductive layer  406  on the surface of the workpiece  200 . In one embodiment, the temperature of the compression head  10  may be increased when at least a portion of the patterned mask layer  408  is pressed to the surface of the workpiece  200 . For example, the compression head  10  may be heated, or the temperature of the processing environment may be increased. The patterned mask layer  408  may have openings exposing a portion of the conductive layer  406 . Then, the compression head  10  and the release film  400  may be removed, as shown in  FIG. 4B . 
         [0041]    Then, an etching process is performed to remove the portion of the conductive layer  406  exposed by the patterned mask layer  408  to pattern the conductive layer  406  so as to form the patterned conductive layer  406   a,  as shown in  FIG. 4C . Then, the workpiece  200  is removed from the fixing device  202  to finish forming an antenna. 
         [0042]    In one embodiment, after the forming of the patterned conductive layer  406   a , the mask layer  408  may be removed depending on application needs, and then an electroplating process or a chemical plating process may be performed to increase the thickness of the patterned conductive layer  406   a.  Alternatively, if the thickness of the conductive layer  406   a  is enough, the mask layer  408  may not be removed. 
         [0043]    The embodiments of the present invention adopt the specific compression head to form the conductive pattern on the surface of the workpiece, which includes an irregular surface, a convexo-concave surface or a curved surface, etc., to prevent the fracture or the deformation of the workpiece and to form the conductive pattern with a precise pattern and a uniform thickness. The conductive pattern of the embodiments of the present invention may be used as, for example, an antenna. 
         [0044]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.