Semiconductor device manufacturing: process – Chemical etching – Combined with the removal of material by nonchemical means
Reexamination Certificate
2007-06-05
2007-06-05
Deo, Duy-Vu N. (Department: 1765)
Semiconductor device manufacturing: process
Chemical etching
Combined with the removal of material by nonchemical means
C438S691000, C438S692000
Reexamination Certificate
active
10957030
ABSTRACT:
Provided is an improved method for producing a silicon wafer whose surfaces exhibit precise flatness and minute surface roughness, and which allows one to visually discriminate between the front and rear surfaces, the method comprising a slicing step of slicing a single-crystal ingot into thin disc-like wafers, a chamfering step of chamfering the wafer, a lapping step for flattening the wafer, an etching step for removing processing distortions on the wafer surfaces, a mirror-polishing step for mirror-polishing the surface of the wafer, and a cleaning step for cleaning the wafer. The etching step further comprises a first acid-etching phase and a second alkali-etching phase, and a rear surface mild polishing step is introduced between the first and second etching phases in order to abrade part of roughness formed on the rear surface of the wafer as a result of the first etching phase.
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Fujimaki Kazuo
Koyata Sakae
Kudo Akihiro
Norimoto Masashi
Takaishi Kazushige
Reed Smith LLP
Sumitomo Mitsubishi Silicon Corporation
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