Patent Publication Number: US-2011049692-A1

Title: Connection device bewteen transistor and lead frame

Description:
FIELD OF THE INVENTION 
     The present invention relates to a connection device, and more particularly, to a connection device connected between a transistor and a lead from so as to increase the rate of communication and reduce the resistance. 
     BACKGROUND OF THE INVENTION 
     A conventional way for connecting transistors is shown in  FIGS. 1 to 3 , and generally includes a connection member  3  connected one of more chips  1  and a lead frame  2  so as to achieve the purpose of communication for signals. The material for making the connection member  3  generally includes gold, copper and aluminum, which can be made in the form of gold wires, copper wires and aluminum wires. In order to avoid from separation of damage during packaging processes, the connection member  3  needs more bonding area  11  when bonded on the transistors  1  and the lead frame  2 . However, the gold wires, copper wires and aluminum wires or pressing copper strip is so thin such that the communication area  31  for the signals is restricted and less than the bonding areas  12 ,  21  on the transistor  1  and the lead frame  2 . This generates significant resistance which deters the communication rate and becomes one of the main concerns in this business. 
     In order to improve the shortcomings mentioned due to high resistance, the present invention provides a second connection member which increases the communication area and the rate of communication by reducing the resistance. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a connection device which comprises a transistor on which a first bonding area is defined, a lead frame on which a second bonding area is defined, a first connection member having two ends thereof bonded on the first and second bonding areas, and a second connection member. The second connection member has two bonding spots on two ends thereof and the two bonding spots are respectively bonded directly on the transistor and on the lead frame or a position of the first connection member wherein the position is not in contact with the transistor and the lead frame or. 
     The primary object of the present invention is to provide a connection device that increases the communication area and reduces the resistance between the transistor and the lead frame. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the first conventional connection member connected between the transistor and the lead frame; 
         FIG. 2  shows the second conventional connection member connected between the transistor and the lead frame; 
         FIG. 3  shows the third conventional connection member connected between the transistor and the lead frame; 
         FIG. 4  shows the connection device of the present invention connected between the transistor and the lead frame; 
         FIG. 5  shows the first embodiment of the connection device of the present invention connected between the transistor and the lead frame; 
         FIG. 6  shows the second embodiment of the connection device of the present invention connected between the transistor and the lead frame; 
         FIG. 7  shows the third embodiment of the connection device of the present invention connected between the transistor and the lead frame; 
         FIG. 8  shows the fourth embodiment of the connection device of the present invention connected between the transistor and the lead frame; 
         FIG. 9  shows the fifth embodiment of the connection device of the present invention connected between the transistor and the lead frame, and 
         FIG. 10  shows the sixth embodiment of the connection device of the present invention connected between the transistor and the lead frame. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 4 , the present invention provides at least one transistor  4 , at least one lead frame  5 , at least one first connection member  6  and at least one second connection member  7 . 
     The transistor  4  includes a first connection area  41  at a pre-chosen area thereof and the first connection member  6  has a first bonding spot  61  on end thereof and which is bonded on the first connection area  41  and the bonding area called the first bonding area  42 . 
     The lead frame  5  includes a second bonding area  51  at a pre-chosen area thereof and the first connection member  6  has a second bonding spot  62  on the other end thereof and which is bonded on the second bonding area  51 . 
     The first connection member  6  is made of gold, copper or aluminum, and made in a form of wire, band or pressing strip. Therefore, the first connection member  6  can be made in the form of gold wire, copper wire, aluminum wire, aluminum band and pressing copper strip. After the first bonding spot  61  is bonded on the first bonding area  42  of the transistor  4  and the second bonding spot  62  is bonded on the second bonding area  51  of the lead frame  5 , the cross section of the first connection member  6  is called the communication area  63  which allows the signals to pass therethrough. 
     The second connection member  7  is made of gold, copper or aluminum, and made in a form of wire, band or pressing strip. Therefore, the second connection member  7  can be made in the form of gold wire, copper wire, aluminum wire, aluminum band and pressing copper strip. 
     The second connection member  7  has a third bonding spot  71  and a fourth bonding spot  72  on two ends thereof. The third bonding spot  71  is bonded on a position of the first connection member  6  wherein the position is not in contact with the transistor  4 . The fourth bonding spot  72  is bonded on a position of the first connection member  6  wherein the position is not in contact with the lead frame  5 . By this way, the area for communication is increased while the resistance between the transistor and the lead frame  5  is reduced, such that the rate for communication is increased. 
       FIGS. 5 to 10  different forms of the first and second connection members  6 ,  7  connected between the transistor  4  and the lead frame  5 .  FIG. 5  shows that the first connection member  6  is in the form of a pressing copper strip and the second connection member  7  is in the form of a pressing copper strip.  FIG. 6  that shows that the first connection member  6  is in the form of a band and the second connection member  7  is in the form of an aluminum wire.  FIG. 7  that shows the first connection member  6  is in the form of a strip and the second connection member  7  is in the form of a gold wire or copper wire.  FIG. 8  shows that the first connection member  6  is in the form of a pressing copper strip and the second connection member  7  is in the form of a band.  FIG. 9  shows that the first connection member  6  is in the form of a pressing copper strip and the second connection member  7  is in the form of an aluminum wire.  FIG. 10  shows that the first connection member  6  is in the form of a pressing copper strip and the second connection member  7  is in the form of a gold wire or copper wire. 
     The shape or number of the first and second connection members  6 ,  7  can be varied according to needs and the number of layer that the second connection member  7  is located above the first connection member  6  can also be increased according to the packing area and height. 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.