Ultrasonic bonding tool, method for manufacturing ultrasonic bonding tool, ultrasonic bonding method, and ultrasonic bonding apparatus

Abstract

An object of the present invention is to provide an ultrasonic bonding tool capable of bonding a lead wire, without any trouble, even to a surface of a thin-film base having a plate thickness of 2 mm or less such as a glass substrate. In the present invention, a surface portion of a chip portion ( 1 c ) of an ultrasonic bonding tool ( 1 ) used in an ultrasonic bonding apparatus has a plurality of planar portions ( 10 ) formed so as to be separated from one another, and a plurality of concavities ( 11 ) formed between the plurality of planar portions. Each of the plurality of planar portions ( 10 ) has a flatness of 2 μm or less.

1 . An ultrasonic bonding tool, comprising:
 a chip portion at a distal end portion of the tool,   wherein the chip portion comprises a surface portion,   wherein the surface portion comprises a plurality of planar portions and a plurality of concavities between planar portions of the plurality of planar portions,   wherein a flatness of the plurality of planar portions is 2 μm or less, and   wherein the tool is capable of applying ultrasonic vibration.   
     
     
         2 . The tool of  claim 1 , wherein an edge of an outer peripheral portion of planar portions in the plurality of planar portions is rounded. 
     
     
         3 . The tool of  claim 1 , wherein the plurality of planar portions has a fine unevenness with a flatness of 2 μm or less. 
     
     
         4 . The tool of  claim 1 , wherein
 the chip portion comprises:   a first layer and   a second layer on the first layer as a most distal end portion of the chip portion, and   wherein the second layer is harder than the first layer.   
     
     
         5 . The tool of  claim 1 , wherein
 the chip portion comprises:   a first layer and   a second layer on the first layer, as a most distal end portion of the chip portion, and   wherein an affinity between the second layer and a material to be bonded is lower than an affinity between the first layer and the material to be bonded.   
     
     
         6 . A method for manufacturing the tool of  claim 1 , comprising:
 (a) preparing a tool original material comprising a distal planar portion with a flatness of more than 2 μm;   (b) grinding the tool original material to enhance the flatness of the distal planar portion to a flatness of 2 μm or less; and   (c) selectively forming the plurality of concavities by wire cutting or with a cutting wheel,   wherein the plurality of concavities separate the distal planar portion into the plurality of planar portions.   
     
     
         7 . The method of  claim 6 , further comprising:
 (d) shot-blasting an edge of an outer peripheral portion of planar portions in the plurality of planar portions, thereby rounding the edge, and   (e) forming fine unevenness having a flatness of 2 μm or less in each planar portion in the plurality of planar portions .   
     
     
         8 . An ultrasonic bonding method for bonding a member to a thin film base, comprising:
 (a) placing a lead wire of the member on a surface of the thin-film base; and   (b) applying pressure and ultrasonic vibration to the lead wire with the tool of  claim 1 , thereby bonding the lead wire onto the surface of the thin-film base, and   wherein, while applying pressure and ultrasonic vibration, a tool width portion corresponding to a widthwise direction of the lead wire is set smaller than a predetermined width of formation of the lead wire.   
     
     
         9 . The method of  claim 8 , further comprising:
 (c) detecting a position of the chip portion with respect to the widthwise direction of the lead wire; and   (d) adjusting a relative positional relationship between the lead wire and the chip portion based on the position detected in (c) such that pressure can be applied to the lead wire within a width of the lead wire while applying pressure and ultrasonic vibration.   
     
     
         10 . An ultrasonic bonding apparatus comprising the tool of  claim 1 . 
     
     
         11 . The tool of  claim 1 , wherein an interval between adjacent concavities of the plurality of concavities is 1.0 mm or less. 
     
     
         12 . The tool of  claim 1 , wherein an average depth of concavities of the plurality of concavities is 0.15 mm or less. 
     
     
         13 . The tool of  claim 1 , wherein the plurality of concavities comprises a plurality of first grooves and a plurality of second grooves that cross the plurality of first grooves. 
     
     
         14 . The tool of  claim 1 , wherein the planar portions of the plurality of planar portions have a rectangular shape, a circular shape, or a rhombic shape. 
     
     
         15 . The tool of  claim 4 , wherein the first layer comprises a steel material and the second layer comprises a super-steel material. 
     
     
         16 . The tool of  claim 15 , wherein the super-steel material is tungsten carbide. 
     
     
         17 . The tool of  claim 5 , wherein an affinity between the second layer and aluminum is lower than an affinity between the first layer and aluminum.