Appeal No. 1997-1248
Application 08/480,109
structure for adhering a semiconductor chip to a supporting
substrate. The invention comprises three specific types of
thin-film layers supported on a chip, namely, a bottom layer
of solder non-wettable material, an intermediate layer of a
mixture of solder wettable and non-wettable material, and a
top layer of solder wettable material. For best results, the
film edges are ideally shaped as a frustum cone and the solder
must have the shape of a ball and it must be electrically and
mechanically attached to said frustum cone structure encasing
the edges of the top and the intermediate layers. The
invention is further illustrated by the following claim.
Representative claim 9 is reproduced as follows:
9. A ball limiting metallurgy pad structure for
mechanically and electrically attaching a ball of solder to a
surface of a substrate, comprising:
a solder non-wettable layer adhering to said surface of
said susbstrate;
a solder wettable layer;
a phased layer comprised of a phased composition of said
solder non-wettable layer and said solder wettable layer
positioned between said solder non-wettable layer and said
solder wettable layer, said phased layer and said solder
wettable layer forming a frustum cone structure on said solder
non-wettable layer; and
2
Page: Previous 1 2 3 4 5 6 7 8 Next
Last modified: November 3, 2007