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In the wet wafer cleaning process, the wafer
surfaces are washed with toxic solutions such as
ammonia and sulfuric acid which was not to allow
to enter the surroundings i.e. clean room.
Therefore, common practice is to reduce the
pressure differential between the wet bench and
the surroundings to a very low pressure
difference level while maintaining a high exhaust
flow rate for toxic fumes. In such a case, the
isolation of process area from the surrounding
area may be compromised i.e. there is a danger
that the surrounding air was suctioned to the
process area. Conceptually, this dilemma can be
solved by creating an air buffer between the
wafer process area and the surrounding area. This
study aims to determine/prove-in the optimal
operational conditions and geometries of such
design by both CFD analysis and experimental
verification.
This thesis includes three parts. First, the
detailed experimental data to a bio-clean bench
installed with the guide-vane design are
conducted. The data are then used to verify the
feasibility/accuracy of the CFD model.
Second, the optimal operational conditions
and geometries of a full-scale isothermal wet
bench with the guide-vane design are determined
by CFD simulation that takes most influential
factors into account. These influential factors
include exhaust pressures, length of the guide-
vane, guide-vane angle and downward face velocity
of the filter etc. The results show that the air
curtain created by the guide-vane is able to
isolate the process area from surrounding area,
and vise-versa.
Third, the thermal effect of ammonia solution
on the distribution of ammonia vapor are
examined. The shape of the thermal plume that
encounters the downward air stream of the filter
is discussed intensively.
In general, this thesis provides significant
information in improving the isolation effect of
wet benches by the air-curtain design.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0714100-143738 |
| Date | 14 July 2000 |
| Creators | Lin, Chih-Hung |
| Contributors | S.C.Hu, Y.K.C, J.J.Hwang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0714100-143738 |
| Rights | not_available, Copyright information available at source archive |
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