Abstract:
A touch device including a substrate and a sensing electrode thereon is provided. An insulation layer is disposed on the sensing electrode, wherein the insulation layer includes a first contact via exposing a part of a terminal of the sensing electrode. A trace is disposed on the insulation layer and electrically connected to the terminal of the sensing electrode through the first contact via. A corner in the first contact via includes a first edge, a second edge, and a third edge, wherein the second edge is disposed between the first edge and the third edge. The first edge and the second edge include a first angle therebetween of greater than 90 degrees, and the second edge and the third edge include a second angle therebetween of greater than 90 degrees.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority of Taiwan Patent Application No. 104100492, filed on Jan. 8, 2015, the entirety of which is incorporated by reference herein. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The disclosure relates to a touch device, and in particular it relates to a contact via in a touch device. 
         [0004]    2. Description of the Related Art 
         [0005]    Conventional touch devices usually include sensing electrodes and traces electrically connected thereto on a substrate. The traces can be electrically connected to a bonding pad set, and the bonding pad set can be further electrically connected to an external circuit (i. e. flexible circuit board). As such, the current or signals can be transferred from the external circuit to the sensing electrodes through the bonding pad set and the traces, thereby driving the touch device. 
         [0006]    In the conventional art, the described elements are usually electrically connected through contact holes. However, residual etchant used in the formation of the contact vias in an etching process usually remains in the corners of the bottom of the contact vias. This residual etchant may cause over-etching problems. In addition, if the corners of the top of the contact vias have an overly small angle (e.g. less than or equal to 90 degrees), it will cause point-discharge problems. Accordingly, a novel contact via is called for to solve the problems described above. 
       BRIEF SUMMARY 
       [0007]    One embodiment of the disclosure provides a touch device, comprising a substrate, a first sensing electrode disposed on the substrate, an insulation layer, and a trace. The insulation layer is disposed on the first sensing electrode. The insulation layer includes a first contact via exposing a part of a terminal of the first sensing electrode. The trace is disposed on the insulation layer and is electrically connected to the terminal of the first sensing electrode through the first contact via. A corner of the first contact via includes a first edge, a second edge, and a third edge. The second edge is disposed between the first edge and the third edge. A line that extends from the first edge and the second edge, and a line that extends from the third edge, define a region that has a first area, which is greater than 0. 
         [0008]    One embodiment of the disclosure provides a touch device, comprising: a substrate; a first sensing electrode disposed on the substrate; an insulation layer disposed on the first sensing electrode, wherein the insulation layer includes a first contact via exposing a part of a terminal of the first sensing electrode; and a trace disposed on the insulation layer and electrically connected to the terminal of the first sensing electrode through the first contact via. A corner of the first contact via includes a first edge, a second edge, and a third edge, and the second edge is disposed between the first edge and the third edge. The first edge and the second edge have an angle therebetween of greater than 90 degrees, and the second edge and the third edge have an angle therebetween of greater than 90 degrees. 
         [0009]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION 
         [0010]    The disclosure can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0011]      FIGS. 1A to 1D  show top views of a touch device during manufacture in one embodiment of the disclosure; 
           [0012]      FIGS. 2A to 2D  show cross sections of the touch device along a line A-A in  FIGS. 1A to 1D , respectively; 
           [0013]      FIGS. 3A to 3E  show top views of a touch device during manufacture in one embodiment of the disclosure; 
           [0014]      FIGS. 4A to 4E  show cross sections of the touch device along a line A-A in  FIGS. 3A to 3D , respectively; 
           [0015]      FIGS. 5A to 5C  show top views of a first contact via in embodiments of the disclosure; and 
           [0016]      FIG. 6  shows a top view of a second contact via in one embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The following description is of the best-contemplated mode of carrying out the disclosure. This description is made for the purpose of illustrating the general principles of the disclosure and should not be taken in a limiting sense. The scope of the disclosure is determined by reference to the appended claims. 
         [0018]      FIGS. 1A to 1D  show top views of a touch device during manufacture in one embodiment of the disclosure.  FIGS. 2A to 2D  show cross sections of the touch device along a line A-A in  FIGS. 1A to 1D , respectively. As shown in  FIGS. 1A and 2A , a black matrix BM is formed on a substrate  10 , and sensing electrodes  11 A and  13 A and connection electrodes  13 B are then formed on the substrate  10 . Sensing electrodes  13 A in the same columns are connected by connection electrodes  13 B. Sensing electrodes  11 A are separated without being connected to each other, and are not in contact with sensing electrodes  13 A and connection electrodes  13 B. Although sensing electrodes  11 A and  13 A are rhombuses with the same area in the following embodiments and drawings, it should be understood that the sensing electrodes can be other shapes (triangle, tetragon, hexagon, or the like) with the same or different areas if necessary. In one embodiment, the substrate  10  can be glass or plastic. In one embodiment, the material of the black matrix BM can be black resin, and the black matrix BM can be formed by sputtering or printing. In one embodiment, the material of sensing electrodes  11 A and  13 A and connection electrodes  13 B can be a transparent conductive material such as indium tin oxide (ITO), and sensing electrodes  11 A and  13 A and connection electrodes  13 B can be formed by sputtering or screen printing. 
         [0019]    As shown in  FIGS. 1B and 2B , an insulation layer  15  is then formed on the substrate  10 , the black matrix BM, sensing electrodes  11 A and  13 A, and connection electrodes  13 B. The material of the insulation layer  15  can be an inorganic material (i.e. silicon oxide or silicon nitride) or an organic material (i.e. photoresist). The insulation layer  15  can be formed by chemical vapor deposition (CVD), physical vapor deposition (PVD), or sputtering. 
         [0020]    As shown in  FIGS. 1C and 2C , first contact vias  17 A are formed to penetrate the insulation layer  15  on terminals of sensing electrodes  11 A over the black matrix BM, and second contact vias  17 B are formed to penetrate the insulation layer  15  on two sides of sensing electrodes  11 A. The first contact vias  17 A and the second contact vias  17 B can be formed by lithography and etching processes. In general, side views of the first contact vias  17 A and the second contact vias  17 B can be inverted trapezoids (narrow bottom and wide top), rectangles (bottom and top are equal in width), or trapezoids (wide bottom and narrow top). Top views of the first contact vias  17 A and the second contact vias  17 B will be described in detail below. 
         [0021]    As shown in  FIGS. 1D and 2D , traces  19 A and connection electrodes  11 B are then formed. In one embodiment, the material of the traces  19 A and connection electrodes  11 B can be metal such as silver, copper, aluminum, an alloy thereof, or transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), a combination thereof, or a multi-layered structure thereof. The traces  19 A and connection electrodes  11 B can be formed by sputtering or screen printing. As shown in  FIG. 2D , the trace  19 A on the insulation layer  15  is electrically connected to the terminal of the sensing electrode  11 A through the first contact via  17 A. Connection electrode  11 B on the insulation layer  15  is electrically connected to the two adjacent sensing electrodes  11 A through the second contact vias  17 B, such that sensing electrodes  11 A in the same column can be electrically connected. It should be noted that, in other embodiments, the connection electrodes  11 B can be formed on the substrate  10 , the insulation layer  15  is then formed on the substrate  10 , the black matrix BM, and the connection electrodes  11 B, and the second contact vias  17 B are formed to penetrate the insulation layer  15  on two sides of connection electrodes  11 B. Sensing electrodes  11 A on the insulation layer  15  is electrically connected to the connection electrodes  11 B through the second contact vias  17 B, such that sensing electrodes  11 A in the same column can be electrically connected. 
         [0022]    The traces  19 A can be also connected to bonding pads (not shown) to electrically connect to an external circuit. It should be understood that sensing electrodes  13 A can be electrically connected to the bonding pads and the external circuit with the described design of the contact vias and the traces. The touch device can be integrated into a display device to complete a touch display apparatus. 
         [0023]      FIGS. 3A to 3E  show top views of a touch device during manufacture in one embodiment of the disclosure.  FIGS. 4A to 4E  show cross sections of the touch device along a line A-A in  FIGS. 3A to 3E , respectively. As shown in  FIGS. 3A and 4A , a black matrix BM is formed on a substrate  10 , and sensing electrodes  13 A and connection electrodes  13 B are then formed. Sensing electrodes  13 A in the same column are electrically connected by connection electrodes  13 B. The materials and methods for forming the substrate  10 , the black matrix BM, sensing electrodes  13 A, and connection electrodes  13 B are similar to that in the embodiment described above, and the related description is therefore omitted here. 
         [0024]    As shown in  FIGS. 3B and 4B , an insulation layer  15  is then formed on the substrate  10 , the black matrix BM, sensing electrodes  13 A, and connection electrodes  13 B. The material and method for forming the insulation layer  15  are similar to that in the embodiment described above, and the related description is therefore omitted here. 
         [0025]    As shown in  FIGS. 3C and 4C , sensing electrodes  11 A and connection electrodes  11 B are then formed on the insulation layer  15 . Sensing electrodes  11 A in the same column are connected by connection electrodes  11 B, and terminals of sensing electrodes  11 A are disposed on the black matrix BM. The material and the method for forming sensing electrodes  11 A and connection electrodes  11 B is similar to that for sensing electrodes  13 A and connection electrodes  13 B, and the related description is therefore omitted here. 
         [0026]    As shown in  FIGS. 3D and 4D , an insulation layer  16  is then formed on the insulation layer  15 , sensing electrodes  11 A, and connection electrodes  11 B. The material and method for forming the insulation layer  16  is similar to that of the insulation layer  15 , and the related description is therefore omitted here. Furthermore, first contact vias  17 A are defined to expose terminals of sensing electrodes  11 A on the black matrix BM. The method for forming the first contact vias is similar to that in the embodiment described above, and the related description is therefore omitted here. 
         [0027]    As shown in  FIGS. 3E and 4E , traces  19 A are then formed. The material and the method for forming the traces  19 A are similar to those in the embodiment described above, and the related description is therefore omitted here. As shown in  FIG. 3E , the traces  19 A on the insulation layer  15  are electrically connected to the terminal of sensing electrodes  11 A through the first contact via  17 A. Similarly, the traces  19 A can be also connected to bonding pads (not shown) to electrically connect to an external circuit. It should be understood that sensing electrodes  13 A can be electrically connected to the bonding pads and the external circuit with the described design of the first contact vias and the traces. The touch device can be integrated into a display device to complete a touch display apparatus. 
         [0028]      FIG. 5A  shows a top view of the first contact via  17 A in one embodiment of the disclosure. In one embodiment,  FIG. 5A  is a cross section of a bottom of the first contact via  17 A, and the cross section of the first contact via  17 A is parallel to a surface of the substrate (and vertical to the direction D which is vertical to a surface of the substrate). Alternatively,  FIG. 5  is a cross section of a top of the first contact via  17 A, and the cross section of the first contact via  17 A is parallel to a surface of the substrate (and vertical to the direction D which is vertical to a surface of the substrate). In other embodiments,  FIG. 5  is a cross section of any cross section between the top and the bottom of the first contact via  17 A, and the cross section of the first contact via  17 A is parallel to a surface of the substrate (and vertical to the direction D which is vertical to a surface of the substrate). 
         [0029]      FIG. 5B  is used to further illustrate the first contact via  17 A in  FIG. 5A . As shown in  FIG. 5B , a corner of the first contact via  17 A is defined by a first edge  171 , a second edge  173 , and a third edge  175 . The second edge  173  is disposed between the first edge  171  and the third edge  175 . The cross section of the first contact via  17 A has an area A, and the cross section of the first contact via  17 A is parallel to a surface of the substrate (and vertical to the direction D which is vertical to a surface of the substrate). The region defined by an extended line of the first edge  171 , the second edge  173 , and an extended line of the third edge  175  has a first area A′ of greater than 0. In one embodiment, the first area A′ and the area A of the cross section have a ratio (A′/A) of 0.4% to 0.8%. An overly large first area A′ may cause an overly high contact resistance. An overly small first area A′ easily results in residual etchant. 
         [0030]    As shown in  FIG. 5B , the first edge  171  and the second edge  173  have a first angle a therebetween of greater than 90 degrees, and the second edge  173  and the third edge  175  have a second angle β of greater than 90 degrees. In one embodiment, the first angle α and the second angle β have a sum of 270 degrees. The first angle α and the second angle β are less than 180 degrees and greater than 90 degrees, respectively. If  FIG. 5B  is a cross section of the bottom of the first contact via  17 A, the first angle α and the second angle β may prevent the etchant remained between the first edge  171  and the second edge  173  (or between the second edge  173  and the third edge  175 ). If  FIG. 5B  is a cross section of the top of the first contact via  17 A, the first angle α and the second angle β may prevent point discharge. 
         [0031]    In one embodiment, the second edge  173  is linear, as shown in  FIG. 5B . In another embodiment, the second edge  173  is curved, as shown in  FIG. 5C . Whether the second edge  173  is linear or curved, it may prevent the residual etchant or point discharge problems. 
         [0032]      FIG. 6  shows a cross section of the second contact vias  17 B, and the cross section is vertical to the direction D of the second contact vias  17 B penetrating the substrate. Similarly, the cross section in  FIG. 6  can be a top, a bottom, or any cross section between the top and the bottom of the second contact vias  17 B. The fourth angle and the fifth angle of the corner of the second contact vias  17 B, the second area (greater than 0) of a region defined by an extended line of the fourth edge, the fifth edge, and an extended line of the sixth edge, the area ratio of the second area and the cross section area, the curved edge, and the like are similar to that of the first contact vias  17 A in  FIGS. 5A to 5C , and the related description is therefore omitted here. 
         [0033]    Although the first contact vias  17 A and the second contact vias  17 B only have one cut corner, it should be understood that the contact vias may have more cut corners. For example, all four corners of the contact vias may have a first edge  171 , a second edge, and a third edge  175 . 
         [0034]    While the disclosure has been described by way of example and in terms of the preferred embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. On 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.