https://doi.org/10.15407/spqeo5.03.332
Semiconductor Physics, Quantum
Electronics & Optoelectronics. 2002. V. 5, N 3. P. 332-336.
PACS: 89.20
Balance model for contactless chemo-mechanical polishing of wafers
Institute of Semiconductor Physics, NAS
of Ukraine, 45 prospect Nauky, 03028 Kyiv, Ukraine
Phone: +380 (44) 265 6189; fax: +380 (44) 265 4110; e-mail: avl@mizar.semicond.kiev.ua
Abstract.
We developed a physical model for polishing. It makes it possible to determine
physico-chemical processes occurring at contactless chemo-mechanical polishing
(CMP) of crystal surfaces. A balance equation for diffusion, convection
and chemical flows is used to describe processes that are proceeding in
the stationary case. The analytical expressions are obtained that relate
polishing rate and surface form for processed material to the physical
parameters of the proceeding processes. It was found that macrorelief
of the processed surface depends not only on the velocity of polishing
plate motion but also on the gap between the processed wafer and polishing
plate, as well as active component diffusion in the etching solution.
One would expect that, at processing conditions discussed, the surface
form is the same for different materials, whatever the active component
concentration and chemical reaction constant.
The polishing rate substantially depends on the concentration of the etchant
active component, chemical reaction, physical properties of sample material
and etching liquid. It is shown that the inverse rate of dissolution is
the sum of inverse limiting rates of chemical, diffusion and convection
stages of the process. The expressions are obtained that make it possible
to optimize technological modes of polishing.
Keywords: chemo-mechanical
polishing, contactless polishing, polishing plate.
Paper received 25.06.02; accepted for publication
10.12.02.
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