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Safe removal of arsenic dust from gallium arsenide crystal pullers.

Authors
Ware-R; Peuchner-R; Tiernan-M
Source
Ware Technical Services, Inc., Westwood, Massachusetts 1995 Sep; :1-17
Link
NIOSHTIC No.
00231899
Abstract
A chemical cleaning process was developed for liquid encapsulated Czochralski crystal pullers which would reduce the exposure of the operators to arsenic (7440382). In this process the arsenic would be transferred from the puller to a container without releasing arsenic dust into the atmosphere. The arsenic could be converted to arsenic-trichloride which will be carried off in a stream of argon gas into a suitable scrubber. Provided precautions were taken to remove residual moisture from the insulation by vacuum baking and keeping the heater temperature below 500 degrees-C, arsenic could be successfully removed from the puller without any attack on the stainless steel components. Molybdenum-chloride formation was avoided by replacement of molybdenum parts by inert materials such as graphite and alumina. Chloride attack on the crystal occurred even when it was raised to the highest possible position. The authors suggest that the process must be operated by removing crystal and crucible before chlorine transport of the arsenic. While the major exposure to arsenic could be avoided, it appears that some exposure is inevitable during removal of the crystal.
Keywords
NIOSH-Grant; Control-technology; Arsenic-compounds; Semiconductors; Industrial-hygiene
Contact
Ware Technical Serv Inc 42 Lorraine Road Westwood, MA 02090
CAS No.
7440-38-2
Publication Date
19950907
Document Type
Final Grant Report
Funding Amount
75177
Funding Type
Grant
Fiscal Year
1995
NTIS Accession No.
PB97-105068
NTIS Price
A03
Identifying No.
Grant-Number-R43-OH-03220
NIOSH Division
OEP
Priority Area
Control-technology
Source Name
Ware Technical Services, Inc., Westwood, Massachusetts
State
MA
Performing Organization
Ware Technical Services, Inc., Westwood, Massachusetts
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