Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2007-02-12
2009-02-03
Sarkar, Asok K (Department: 2891)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C257SE21508, C438S614000, C438S615000
Reexamination Certificate
active
07485564
ABSTRACT:
A system and method for eliminating undercut when forming a C4 solder bump for BLM (Ball Limiting Metallurgy) and improving the C4 pitch. In the process, a barrier layer metal stack is deposited above a metal pad layer. A top layer of the barrier layer metals (e.g., Cu) is patterned by CMP with a bottom conductive layer of the barrier metal stack removed by etching. The diffusion barrier and C4 solder bump may be formed by electroless plating, in one embodiment, using a maskless technique, or by an electroplating techniques using a patterned mask. This allows the pitch of the C4 solder bumps to be reduced.
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Daubenspeck Timothy H.
Gambino Jeffrey P.
Muzzy Christopher D.
Sauter Wolfgang
International Business Machines - Corporation
Sarkar Asok K
Scully , Scott, Murphy & Presser, P.C.
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