Semiconductor device manufacturing: process – Repair or restoration
Reexamination Certificate
2002-08-16
2003-07-29
Elms, Richard (Department: 2824)
Semiconductor device manufacturing: process
Repair or restoration
C438S478000, C438S481000, C438S977000, C438S974000
Reexamination Certificate
active
06599758
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to semiconductor wafer production.
BACKGROUND OF THE INVENTION
In general, semiconductor wafers are prepared in several steps, including (1) growing a single crystal ingot out of molten silicon, (2) sawing the single crystal ingot into wafers, (3) shaping or lapping the wafers, (4) performing a rough polish, and (5) depositing an epilayer of silicon substrate. The epilayer is often deposited using chemical vapor, high temperature deposition to form a single crystal silicon layer on the surface of the wafer. Once the wafers have been prepared, they are provided to a fabrication facility (fab) for further processing.
As fabs are processing smaller and smaller line widths and devices are continually shrinking, the wafer surface affects the entire fab processing. Furthermore, a particle that was once “invisible” can now completely ruin a device. Also, the surface of an epitaxial wafer exhibits characteristics known as “microsteps.” Microsteps occur because the surface of the wafer is crystalline and when it is sawed, the surface is disoriented with respect to the crystallographic planes. Therefore, despite the wafers being sawn and polished, the resulting surface has these microsteps across its surface.
SUMMARY OF THE INVENTION
In response to the problems discussed above, described herein is a system and method for handling post-epitaxial thermal oxidation. In one embodiment, the method produces semiconductor wafers by performing the steps of forming a wafer substrate, depositing an epilayer on the substrate, oxidizing a top portion of the epilayer, and removing the oxidized top portion. As a result, the wafer includes an epi-surface that is very smooth, with little or no microsteps thereon.
REFERENCES:
patent: 4615762 (1986-10-01), Jastrzebski et al.
patent: 6240933 (2001-06-01), Bergman
patent: 6312968 (2001-11-01), Shimabukuro et al.
Kenny Danny
Lindberg Keith
Elms Richard
Jones Day
MOS EPI, Inc.
Owens Beth E.
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