Wire bonding method

Abstract

A wire bonding method with the process of performing a first bonding to a pad of a die that is a first bond point, and the process of performing a second bonding to an interconnect wiring (or a lead) that is a second bond point, thus connecting the pad and the interconnect wiring with a wire. A bump is first formed on a pad, and, in a wire cutting step performed during the step of forming the bump, the wire protruding from the tip end of a capillary is bent in the lateral direction to form a bent part, and then the bent part is bonded to the bump, thus completing the first bonding process; after which the wire is bonded to the interconnect wiring, thus completing the second bonding process.

1 . A wire bonding method performing first bonding to a die pad that is a first bond point and then second bonding to an interconnect wiring that is a second bond point, thus connecting said die pad and interconnect wiring, said method comprising sequentially: 
 a bump forming process for forming a bump on a die pad, said bump forming process including a step of cutting and bending a wire protruding from a tip end of a capillary in a lateral direction thus forming a bent part in said wire;    a first bonding process for bonding said bent part of said wire to said bump; and    a second bonding process for bonding said wire to said interconnect wiring.    
     
     
         2 . A wire bonding method performing first bonding to an interconnect wiring that is a first bond point and second bonding to a die pad that is a second bond point, thus connecting said interconnect wiring and die pad, said method comprising sequentially: 
 a bump forming process for forming a bump on a die pad, said bump forming process including a step of cutting and bending a wire protruding from a tip end of a capillary in a lateral direction thus forming a bent part in said wire;    a first bonding process for bonding said bent part to said interconnect wiring thus forming a lower first bonding part, said first bonding process further raising and moving said capillary above said lower first bonding part then lowering said capillary and superimposing and connecting said wire onto said lower first bonding part thus forming an upper first/bonding part; and    a second bonding process for bonding said wire to said bump on said die pad.    
     
     
         3 . The wire bonding method according to  claim 1  or  2 , wherein said bent part is formed by holding said wire with a clamper, and moving said damper in said lateral direction, thus cutting said wire.  
     
     
         4 . The wire bonding method according to  claim 1 , wherein said bent part is formed by the steps of holding said wire with a clamper, and then moving said capillary parallel to a direction for joining said interconnect wiring and die pad and toward said interconnect wiring, thus cutting said wire.  
     
     
         5 . The wire bonding method according to  claim 1  or  2 , wherein said bump forming process comprises the ordered steps of: 
 bonding a ball formed at an end of said wire to said die pad,    raising said capillary so that a edge at a lower end of said capillary is positioned within a height of a pillar portion formed on said bump,    moving said capillary in said lateral direction thus forming a small thickness portion on a connected portion of said bump and wire,    raising said capillary by a fixed amount, and    pulling said wire thus cutting said wire from said small thickness portion.    
     
     
         6 . The wire bonding method according to  claim 1  or  2 , wherein said a bump forming process comprises the ordered steps of: 
 bonding a ball formed at an end of said wire to said die pad,    pressing said ball with said capillary to form a small thickness portion and a ball neck portion that can be teared off at a lower part thereof when said wire is pulled, and    pulling said wire diagonally upward thus separating said ball neck portion from said small thickness portion.