Semiconductor device

Abstract

In order to inhibit a crack under a pad opening without increasing a chip size, a protective film ( 6 ) includes a pad opening ( 9 ) that exposes a part of a topmost layer metal film ( 3 ). The pad opening ( 9 ) is rectangular and square, and has an opening width of d0. A second metal film ( 2 ) has an opening under the pad opening ( 9 ). The opening is rectangular and square, and has an opening width of d4. A distance between an opening edge of the protective film ( 6 ) and an opening edge of the second metal film ( 2 ) is d3. The second metal film ( 2 ) has a rectangular donut shape, and protrudes to an inner side of the pad opening ( 9 ) by the distance d3.

1 . A semiconductor device having a pad structure comprising a plurality of metal films, the semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on a surface of the semiconductor substrate;   a first metal film formed on the first insulating film;   a second insulating film formed on the first metal film;   a first part of the second metal film formed on the second insulating film;   a first via formed in the second insulating film to connect the first metal film and the first part of the second metal film;   a third insulating film formed on the first part of the second metal film;   a topmost layer metal film formed on the third insulating film;   a second via formed in the third insulating film to connect the first part of the second metal film and the topmost layer metal film; and   a protective film formed on the topmost layer metal film and having a pad opening formed therein to expose a part of a surface of the topmost layer metal film,   the first part of the second metal film having a rectangular donut shape and having an opening under the pad opening,   the opening being located outside a beveled corner at a tip of a capillary for a ball bonder used for ball bonding,   the first part of the second metal film protruding to an inner side of the pad opening by a predetermined amount of protrusion.   
     
     
         2 . A semiconductor device according to  claim 1 , wherein both the pad opening and the opening are square. 
     
     
         3 . A semiconductor device according to  claim 2 , wherein the predetermined amount of protrusion satisfies the following relationship:
     d 3=( d 0− d 4)/2,
   
       where d3 is the predetermined amount of protrusion, d0 is a length of a side of the pad opening, and d4 is a length of a side of the opening in the first part of the second metal film in the same direction as the side of the pad opening. 
     
     
         4 . A semiconductor device according to  claim 2 , wherein the following relationship is satisfied:
   d0>r2 and d4>r1,   
       where d0 is a length of a side of the pad opening, d4 is a length of a side of the first part of the second metal film located under a side of the opening, r2 is a width of a crushed ball, and r1 is a width of the beveled corner. 
     
     
         5 . A semiconductor device according to  claim 1 , further comprising a second part of the second metal film formed under the pad opening, being absent under the beveled corner in the ball bonding, so as to avoid being held in contact with the first part of the second metal film having a rectangular donut shape and formed under the pad opening, the second part of the second metal film being rectangular or circular in cross section. 
     
     
         6 . A semiconductor device according to  claim 1 , further comprising a second part of the second metal film formed under the pad opening, being absent under the beveled corner in the ball bonding, so as to avoid being held in contact with the first part of the second metal film having a rectangular donut shape and formed under the pad opening, the second part of the second metal film comprising a combination including a group of a plurality of rectangles or circles in cross section. 
     
     
         7 . A semiconductor device according to  claim 5 , wherein the second part of the second metal film being rectangular or circular is electrically connected to the topmost layer metal film through the second via. 
     
     
         8 . A semiconductor device according to  claim 1 , wherein the first part of the second metal film has a slit formed therein. 
     
     
         9 . A semiconductor device according to  claim 1 , further comprising an element formed under the pad opening. 
     
     
         10 . A semiconductor device according to  claim 9 , wherein the element is an ESD protection element.