Bond tool for notching a lead in semiconductor package

Abstract

A bond tool is used in semiconductor package to break a lead at a notch formed thereon and then bonds the broken lead to a die pad. In an embossing-type bond tool, an end thereof is provided with a projected portion for vertically pressing against the lead to form a transversely extended groove thereon. In a scissor-type bond tool, an end thereof is formed into two opposite sharp blades for horizontally cutting the lead at two lateral edges thereof to provide two symmetrical cuts. Unlike the conventional notches that are formed on the lead during the complicate forming process of the lead, the groove and the symmetrical cuts are easily formed on the straight lead without notch to provide a weak point at reduced manufacturing cost. The difficulties in forming the conventional notches on the lead due to the highly precise lead windows, lead width, and lead pitch can therefore be avoided and thus improve the yield for manufacturing of lead bond substrates.

What is claimed is:  
     
         1 . A bond tool for notching a lead in semiconductor package, comprising an end formed into a substantially flat surface, and a projected portion diametrically extended across said flat surface to axially rise from said flat surface by a predetermined height; whereby by positioning and pressing said end of said bond tool having said projected portion against a lead to be notched with said projected portion transversely extended across a width of said lead, a transverse groove is formed across said lead at a predetermined position to serve as a weak point for said bond tool to break said lead at said groove before bonding said broken lead.  
     
     
         2 . The bond tool as claimed in  claim 1 , wherein said projected portion has a cross section in the shape of a rectangle.  
     
     
         3 . The bond tool as claimed in  claim 1 , wherein said projected portion has a cross section in the shape of an inverted trapezoid.  
     
     
         4 . The bond tool as claimed in  claim 1 , wherein said projected portion has a cross section in the shape of a semicircle or any other advantageous shape.  
     
     
         5 . The bond tool as claimed in  claim 1 , wherein said projected portion has a length longer than a width of said lead to be notched, so that said groove formed on said lead transversely extends a full width of said lead.  
     
     
         6 . The bond tool as claimed in  claim 1. , wherein the location of forming the notch will be exactly the same as bonding tool application point, thus simplifying the lead bonding process  
     
     
         7 . A bond tool for notching a lead in semiconductor package, comprising an end in the shape of an inverted letter “V” to provide two spaced sharp blades, said blades being adapted to form two symmetrical cuts at predetermined positions on two lateral edges of a lead to be notched, whereby said two symmetrical cuts serve as a weak point for said bond tool to break said lead thereat before bonding said broken lead.