Appeal No. 2001-2082
Application No. 08/943,146
eutectic portion (specification, page 4). A surface portion on
the first substrate designates the location of bonding with the
second substrate (specification, pages 9 & 10). Layers of
titanium and gold are deposited on the second substrate wherein
the titanium layer deoxidizes a naturally formed oxide layer on
the surface portion of the first substrate while the gold layer
forms the gold-silicon eutectic portion (specification, pages 22
& 23). By eliminating the naturally formed silicon oxide, a
uniform and void-free eutectic layer can be formed that contacts
the entire surface portion resulting in a stable and uniform
bonding interface (specification, page 23).
Representative independent claims 1 and 21 are reproduced as
follows:
1. A semiconductor device comprising:
a first substrate having a surface portion made of
silicon;
a second substrate bonded to the first substrate;
an eutectic portion of silicon and gold interposed
between the first and second substrates to directly contact
the surface portion of the first substrate at a first
surface thereof and containing an oxide of metal that has
deoxidized silicon oxide, the oxide of metal existing in the
eutectic portion apart from the first substrate; and
2
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