Patent Publication Number: US-2005133912-A1

Title: Electrical connection structure

Description:
This application claims the benefit of Taiwan application Serial No. 92136641, filed Dec. 23, 2003, the subject matter of which is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates in general to an electrical connection structure, and more particularly to an electrical connection structure for electrically connecting with a chip with bearing element.  
      2. Description of the Related Art  
      In response to the market demand in slimness, thinness, lightness and compactness, electronic products disposed with liquid crystal display (LCD) are engaged in relevant configuration technology such as tape carrier package (TCP) technology, chip on glass (COG) technology and chip on film (COF) technology, etc.  
      TCP technology is mainly applied in large-sized LCD panels, while COG technology is mainly in medium to small sized LCD panels. In order to reduce costs, COG is also applied in large sized LCD panels. In recent years, in order to further miniaturize joint interval, researchers are dedicated to the R&amp;D of COF technology for LCD panel to have a higher resolution.  
      During the liquid crystal display module (LCM) manufacturing process, the TCP technology and the COF technology have a driver IC disposed on a tape or a thin film used for connecting with an LCD panel with a source PCB (or gate PCB), so that the required space for the driver IC to be disposed on the LCD panel or the source PCB can be saved. The COG technology has the driver IC directly disposed on the glass substrate of the LCD panel, so that the bump on the driver IC can be electrically connected to the circuit on the glass substrate directly.  
      Referring to  FIG. 1 , a diagram according to a conventional electrical connection structure is shown. In the LCM, the conventional electrical connection structure is for electrically connecting with a chip of the driver IC with a bearing element. The bearing element can be a thin film used in COF, a tape used in TCP, or a glass substrate used in COG.  
      For the purpose of illustration, the chip has first surface  102  illustrated in dotted lines. Besides, the bearing element has a second surface  104  corresponding to the first surface  102 . In contrast to first surface  102 , the second surface  104  is illustrated in solid lines.  
      The conventional electrical connection structure mainly includes a plurality of outer contact points  106  and inner contact points  108  such as bumps, and a plurality of outer conducting wires  110  and inner conducting wires  112  such as inner leads.  
      The outer contact points  106  are disposed on the outer side of the first surface  102  of the chip. The inner contact points  108  are disposed on the inner side of the first surface  102 . Moreover, the inner contact point  108  alternate with the outer contact points  106  with each inner contact point  108  being disposed between two outer contact points  106 .  
      The outer contact points  106  and the inner contact point  108  are connected with the inner conductive connect of the chip. Moreover, the outer contact points  106  and the inner contact point  108  are exposed on the first surface  102  of the chip, wherein the chip can be electrically connected with other elements via the inner contact points  106  and the outer contact points  108  to achieve a better performance.  
      Furthermore, the outer conducting wires  110  are disposed on the second surface  104  of the bearing element, while the outer conducting wires  110  correspond to the outer contact points  106  disposed on the first surface  102  of the chip. On the other hand, the inner conducting wires  112  are also disposed on the second surface  104 , and the inner conducting wires  112  correspond to the inner contact point  108  disposed on the first surface  102 .  
      As shown in  FIG. 1 , the first surface  102  as well as the outer contact points  106  and the inner contact point  108  disposed on the first surface  102  are illustrated in dotted lines. The second surface  104  as well as the outer conducting wire  110  and the inner conducting wire  112  disposed on the second surface  104  are illustrated in solid lines. Before the chip is electrically connected with the bearing element, the first surface  102  and the second surface  104  are separated from each other. The diagram shows the electrical connection status between the chip and the bearing element when the chip and the bearing element are electrically connected via the first surface  102  and the second surface  104  respectively.  
      By means of the outer contact points  106  and the inner contact points  108  disposed on the chip as well as the outer conducting wires  110  and the inner conducting wires  112  disposed on the bearing element, the chip and the bearing element can be electrically connected via the electrical contact between the outer contact points  106  and the outer conducting wires  110  as well as the electrical contact between the inner contact point  108  and the inner conducting wires  112 .  
      It can be seen in the diagram that using a conventional electrical connection structure to electrically connect the chip and the bearing element, 13 contact points are positioned on the outer side and inner side of the first surface  102  within the distance of 450 μm from the leftmost contact point to the rightmost contact point disposed on the first surface  102  of the chip, with X 1 , the interval between each outer contact point  106  and each inner conducting wire  112 , being equal to 11.5 μm.  
      Due to alignment error and further due to X 1 , the interval between the outer contact points  106  and the inner conducting wire  112 , being too small, the outer contact points  106  might electrically contact the inner conducting wire  112 , causing short-circuit to occur between the outer contact points  106  and the inner conducting wire  112  when the chip and the bearing element are connected. The short-circuit occurring between the chip and the bearing element due to a narrow interval X 1  impedes the performance of LCM.  
     SUMMARY OF THE INVENTION  
      It is therefore an object of the invention to provide an electrical connection structure whose outer contact point of the chip is unlikely to have electrical contact with the inner conducting wire of the bearing element, preventing the occurrence of short-circuit between the chip and the bearing element when the chip and the bearing element jointed together correspondingly.  
      The invention achieves the above-identified object by providing an electrical connection structure for electrically connecting with a chip and a bearing element. The chip has a first surface, while the bearing element has a second surface corresponding to the first surface. The electrical connection structure includes two outer contact points, M inner contact points, two outer conducting wires, and M inner conducting wires. The two outer contact points disposed on the first surface. The M inner contact points are disposed on the first surface and correspond to the inner side of the first surface on which the two outer contact points are positioned, wherein the M inner contact points are positioned between the two outer contact points, where M is a positive integer greater than or equal to 2. The two outer conducting wires are disposed on the second surface, wherein the two outer conducting wires correspond to the two outer contact points. The M inner conducting wires re disposed on the second surface and correspond to the M inner contact points. The chip and the bearing element are electrically connected via the electrical contact between the two outer contact points and the two outer conducting wires as well as the electrical contact between the M inner contact points and the M inner conducting wires, wherein at least one of the M inner conducting wires is bent and extends along the outer direction of the first surface.  
      In the above electrical connection structure of the invention, the inner conducting wire can be bent at an angle of 45, 90 or 135 degrees, or the bending deflection of the inner conducting wire can be arc-curved. The two outer contact points and the M inner contact points can be bumps, wherein the bumps can be gold bumps.  
      Furthermore, in the above electrical connection structure of the invention, the bearing element can be a thin film used in COF, a tape used in TCP, or a glass substrate on COG, while the two outer conducting wires and the M inner conducting wires can be inner leads.  
      Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagram illustrating a conventional electrical connection structure;  
       FIG. 2  is a diagram illustrating an electrical connection structure according to a preferred embodiment of the invention;  
       FIG. 3A  is a diagram illustrating the status when an inner conducting wire is bent at an angle of 45 degrees;  
       FIG. 3B  is a diagram illustrating the status when an inner conducting wire is bent at an angle of 90 degrees;  
       FIG. 3C  is a diagram illustrating the status when an inner conducting wire is bent at an angle of 135 degrees;  
       FIG. 3D  is a diagram illustrating the status when an inner conducting wire is arc-curved. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The invention is exemplified by a preferred embodiment. However, the preferred embodiment will not limit the scope of protection of the invention. The preferred embodiment is an electrical connection structure under the spirit of the invention. The characteristics of the technology of the invention are disclosed below.  
      Referring to  FIG. 2 , a diagram illustrating an electrical connection structure according to a preferred embodiment of the invention is shown. The electrical connection structure of the invention normally electrically connects a chip of driver IC and a bearing element during LCM manufacturing process. The bearing element can be a thin film used in COF, a tape used in TCP, or a glass substrate on COG.  
      To clearly disclose the characteristics of the structure of the invention, a first surface  202  of a chip in  FIG. 2  is illustrated in dotted lines, and so are the elements disposed on first surface  202 . Besides, a second surface  204  of a bearing element is illustrated in solid lines and so are the elements disposed on the second surface  204 , wherein the second surface  204  corresponds to the first surface  202 .  
      Before the chip and the bearing element are electrically connected, the first surface  202  and the second surface  204  are separated from each other.  FIG. 2  illustrates the status when the chip and the bearing element are jointed and electrically connected via the first surface  202  and the second surface  204  respectively.  
      The electrical connection structure of the invention mainly includes two outer contact points  206   a  to  206   b , M inner contact points  208   a  to  208   b , the two outer conducting wires  210   a  and  210   b , and M inner conducting wires  212   a  to  212   b , where M is an integer greater than or equal to 2. Here, we take M equal to 2 for illustration.  
      The two outer contact points  206   a  to  206   b  are disposed on first surface  202  of the chip and so are the two inner contact points  208   a  to  208   b  disposed thereon. Corresponding to the two outer contact points  206   a  to  206   b , the two inner contact points  208   a  to  208   b  are positioned on the inner side of the first surface  202 . Moreover, the two inner contact points  208   a  to  208   b  are disposed inside while the two outer contact points  206   a  to  206   b  are disposed outside with the inner contact points  208   a  to  208   b  being positioned between the two outer contact points  206   a  and  206   b.    
      On the other hand, the corresponding outer conducting wires  210   a  to  210   b  of the outer contact points  206   a  to  206   b  are disposed on the second surface  204  of the bearing element, and so are the inner conducting wires  212   a  to  212   b  disposed thereon. Moreover, the inner conducting wires  212   a  to  212   b  correspond to the inner contact points  208   a  to  208   b  disposed on the first surface  202  of the chip, while the above inner conducting wires  212   a  to  212   b  are aligned in parallel with the outer conducting wires  210   a  to  210   b.    
      The above outer contact points  206   a  to  206   b  and the inner contact points  208   a  to  208   b  can be bumps normally disposed on the chip, wherein the bumps can be gold bumps. Moreover, the outer conducting wires  210   a  to  210   b  and the inner conducting wires  212   a  to  212   b  can be inner leads.  
      As shown in the diagram, The chip and the bearing element can be electrically connected via the electrical connection between the outer contact points  206   a  to  206   b  disposed on the first surface  202  of the chip and the outer conducting wires  210   a  to  210   b  disposed on the second surface  204  of the bearing element as well as via the electrical connection between the inner contact points  208   a  to  208   b  disposed on first surface  202  of the chip and the inner conducting wires  212   a  to  212   b  disposed on the second surface  204  of the bearing element. In the above electrical connection structures of the invention, the inner conducting wires  212   a  to  212   b  are aligned between the two outer contact points  206   a  to  206   b  at an equal distance.  
      It can be seen in  FIG. 2 , the characteristic of the electrical connection structure of the invention is that the two inner conducting wires  212   a  to  212   b  disposed on the second surface  204  of the bearing element respectively has a bending deflection. Moreover, the inner conducting wires  212   a  to  212   b  are bent and extend along the outer direction of the first surface  202  of the chip.  
      The inner conducting wires are exemplified by the inner conducting wires  212   a  and  212   b . Before the inner conducting wires  212   a  to  212   b  disposed on the second surface  204  of the bearing element extend along the outer direction of the first surface  202  of the chip, a bending deflection is formed on the inner conducting wire first, then the inner conducting wires  212   a  to  212   b  extend along outer direction of the first surface  202  of the chip.  
      Due to the bending deflection, a larger interval X 2  will respectively be allowed between the inner conducting wires  212   a  to  212   b  and the outer contact points  206   a  to  206   b  of chip.  
      In the above preferred embodiment of the invention, the number of the inner contact points positioned between two outer contact points is not necessary to be 2; the number of the inner contact points can be equal to greater than 2 and still within the scope of protection of the invention. Furthermore, the number of the outer contact points positioned between the inner contact points is not necessary to be 1. Besides, the inner conducting wire adjacent to the outer contact points of the preferred embodiment of the invention, a wider interval between the inner conducting wire and the outer contact points can be achieved by having a bending deflection of the inner conductive line formed between the outer contact point and the inner contact point, wherein the deflection of the inner conductive line adjacent to the outer contact point is bent from the vicinity of the inner contact point and bent towards the outer contact points.  
      Refer to FIGS.  3 A˜ 3 D.  FIG. 3A ˜ FIG. 3C  are diagrams illustrating the status when an inner conducting wire is respectively bent at an angle of 45, 90 and 135 degrees, while  FIG. 3D  is a diagram illustrating the status when an inner conducting wire is arc-curved. It can be seen from the diagrams that no matter the angle Y at the bending deflection on the inner conducting wire is bent at an angle of 45 degrees as in  FIG. 3A , 90 degrees as in  FIG. 3B  or 135 degrees as in  FIG. 3C , or the bending deflection on the inner conducting wire is arc-curved as in  FIG. 3D , an interval X 2  wider than the interval X 1  according to prior art can be obtained between the inner conducting wire  312   a  and the outer contact points  306   a  as well as between the inner conducting wire  312   b  and the outer contact points  306   b.    
      It can be understood from a preferred embodiment according to the invention that the chip and the bearing element are electrically connected via an electrical connection structure of the invention. As shown in  FIG. 2 , under the same conditions with that of a conventional electrical connection structure as in  FIG. 1 , there are 13 contact points positioned on the outer side and inner side of the first surface  202  within the distance of 450 μm from the leftmost contact point to the right most contact point disposed on the first surface  202  of the chip, wherein X 2 , the interval between each outer contact point, the outer contact points  206   a  for instance, and each inner conducting wire, the inner conducting wire  212   a  for instance, can be enlarged to be 14 μm. The width of X 2  is much wider than that of X 1 , i.e., 11.5 μm, the interval between each outer contact point  106  and each inner conducting wire  112  in  FIG. 1 .  
      Therefore, the electrical connection structure according to the invention disclosed above and the set of chip and bearing element having the electrical connection structure have the following advantages. With the bending deflection on the inner conducting wire, X 2 , the interval between the outer contact points and the inner conducting wire can be largely widened. When the chip and the bearing element are connected, the outer contact points  206   a  will be less likely to have electrical contact with the inner conducting wire  212   a , and so will the short-circuit between the outer contact points  206   a  and the inner conducting wire  212   a  be less likely to occur. Consequently, the LCM can have a better performance.  
      While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.