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SEMI F5-1101 © SEMI 1990 , 2001 11 Table 1 Exhaust Sy stem Selection Table Proces s Gases/Chemi cals Reason for POU Abat ement POU Abat ement Present End-of-p ipe Exhaust Syste m Type VOC Yes Gener al Solvent/strippe rs …

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SEMI F5-1101 © SEMI 1990, 2001 10
exhaust can be used instead of, or in addition to,
dilution air.
10.8.2.1 Accidental release abatement devices may be
any of the types described in this guide.
10.8.2.2 In some applications, gas cabinet exhaust is
diverted to an abatement device only upon detection of
an accidental release.
10.8.2.3 When designing diversion systems, the ability
of the abatement device to operate after extended
periods of disuse must be considered.
11 Summary Table
11.1 See Table 1 for suggestions about using POU and
end-of-pipe abatement systems for different types of
processes, materials, and exhaust systems.
12 Alternative Approaches
12.1 This guide is primarily concerned with handling
gas effluents that arise from semiconductor processing.
Capture and abatement is not the only approach to
avoid release of hazardous materials. If possible, use of
the hazardous materials should be avoided. In theory
the following approach should be used:
12.1.1 Replace the hazardous material with one that is
non-hazardous or less hazardous.
12.1.2 If replacement is not possible, use less of the
material.
12.1.3 If possible, totally enclose the system so all
material is recovered and reused.
12.1.4 If none of the above can be achieved, fit
effective abatement devices.
13 Related Documents
NOTE 9: Unless otherwise indicated, all documents cited
shall be the latest published versions.
13.1 SEMATECH Documents
3
TT97093364A-XFR — Point-of-Use (POU) Control
Systems for Semiconductor Process Emissions
(ESHC003), October 30, 1997, J. Michael Sherer, P.E.,
Motorola (available online from
www.sematech.org\ public\ docubase\ summary\ 3364AX
FR.htm)
13.2 FM Global Documents
4
3 SEMATECH/International SEMATECH, 2706 Montopolis Drive,
Austin, Texas 78741-6499
4 FM Global Corporation, 1151 Boston-Providence Turnpike,
Norwood, MA 02062 or the FM Global Web Site at:
www.fnglobal.com
Property Loss Prevention Sheet 7-78 — Industrial
Exhaust Systems
13.3 Other Documents
Design and Selection of Spray/Mist Elimination
Equipment
5
Toxicological Investigation in the Semiconductor
Industry
6
Reactions of Exhaust Deposits from Silicon Deposition
Tools
7
Treatment of Organochlorines from Plasma Etch
Processing
8
Toxicological Hazards of Plasma Etch Waste Products
9
Packed Column Internals
10
13.4 I300I/International Sematech
11
Emissions Characterization 2.4b — www.I300I.org,
Zero Impact Process Team.
5 Chemical Engineering Volume 91, No. 21, 82–89 (October 15,
1984), Holmes, T. L.; and Chen, G. K.
6 Toxicology & Industrial Health 8 (141) 1992 by Bauer; et. al.
7 Semiconductor Safety Association Conference, Orlando, April
1997 by Creighton S.; Plaster, M.; and Nicholson, T.
8 Semiconductor Safety Technology, March 1995 by Baker, D.;
Smith, J.; and Mawle, P.
9 Semiconductor Safety Technology, July 1996 by Bauer. F; Wolff,
I.; and Schmidt, R.
10 Chemical Engineering, Volume 91, No. 5, pp 40–51 March 5,
1984 by Chen, G. K.
11 I300I/International Sematech, 2706 Montopolis Drive, Austin,
Texas 78741-6499
SEMI F5-1101 © SEMI 1990, 200111
Table 1 Exhaust System Selection Table
Process Gases/Chemicals Reason for POU
Abatement
POU
Abatement
Present
End-of-pipe Exhaust System Type
VOC Yes GeneralSolvent/strippers
No VOC
Vapor prime HMDS No Acid or ammonia
Acid baths HCl/HF/Acetic No Acid
Aqua regia/hot nitric No Acid aerosolsAcid baths
Yes Acid
NH
3
No AmmoniaAmmonia baths
Yes Acid
No AcidCorrosives
Yes Acid
No AmmoniaAmmonia
Yes Acid
Gas bottle purge
Hydrides/pyrophorics Yes General
No General
Ammonia No Ammonia
VOC No VOC
Chemical dispensing
Corrosives No Acid
HNO
3
/NO
x
Yes AcidChemical wafer thinning of
raw wafers
No NOx/acid scrubber
EPI H
2
/Hydrides/HCl Fire and safety
Solids blockage
Yes Acid, H
2
reclaim, or general
Dry etching – metal Cl and Br chemistries Blockage/Corrosion Yes Acid
Dry etching – oxide/poly/etc. Fluoride chemistry No Acid
LPCVD nitride SiH
2
Cl
2
/NH
3
Solids blockage
Fire and safety
Yes Acid
LPCVD poly/oxide SiH
4
/fluoride
chemistry
Fire and safety
Solids blockage
Yes Acid
PECVD – poly/oxide SiH
4
/fluoride
chemistry
Fire and safety
Solids blockage
Yes Acid
SiH
4
/WF
6
/H
2
Fire and safety
Solids blockage
Yes AcidPECVD nitride and tungsten
SiH
4
/NH
3
Fire and safety
Solids blockage
Yes Acid
Implant Hydrides, BF
3
Hazardous deposits Yes Acid
Ammonia No AmmoniaRTP
Yes General
NOTE T1: POU Abatement may be used for the reduction of PFCs and by-products from the process.
SEMI F5-1101 © SEMI 1990, 2001 12
APPENDIX 1
END-OF-PIPE ABATEMENT DESIGN
NOTE: The material in this appendix is an official part of SEMI F5 and was approved by full letter ballot
procedures on August 27, 2001.
A1-1 Referenced Documents
A1-1.1 Gas-Liquid Reactions
12
A1-1.2 Design and Selection of Spray/Mist
Elimination Equipment
13
A1-1.3 Absorption, Distillation, and Cooling Towers
14
A1-1.4 Perry' s Chemical Engineers' Handbook
15
A1-1.5 Absorption and Extraction
16
A1-1.6 Mass Transfer
17
A1-1.7 Mass-Transfer in Co-current Gas-Liquid
Flow
18
A1-1.8 Mass-Transfer Operations
19
A1-2 Principles
A1-2.1 Principles of gas absorption and methods of
design of gas absorption equipment are treated
extensively in chemical engineering literature (See
Sections A1-1.1–A1-1.8). The sources cited present
rigorous methods for design.
A1-2.2 Practical design of scrubbers is at least semi-
empirical; and in the case of air pollution abatement
systems, design is often directly based on experimental
data.
A1-2.2.1 Consequently, designs should be based on
mass-transfer coefficients that have been determined
experimentally under, as nearly as possible, the
conditions of expected scrubber operation.
A1-2.2.2 It should be noted that the typical
concentrations of the existing empirical data base is
several orders of magnitude greater than the typical
concentrations of corrosives exiting a semiconductor
12 McGraw-Hill, New York (1970), Danckwerts, P.V.
13 Chemical Engineering Volume 91, No. 21, pp 82-89 (October 15,
1984), Holmes, T. L.; and Chen, G. K.
14 Longmans, Green, London (1961), Norman, W. S.
15 6th Edition, McGraw-Hill; New York (1984), Perry, R. H.; and
Green, D.
16 2nd Edition; McGraw-Hill, New York (1952), Sherwood, T. K.;
and Pigford, R. L.
17 McGraw-Hill, New York (1975), Sherwood, T.K.; Pigford, R. L.;
and Wilke, C. R.
18 Chemical Engineering Sciences Volume 33, No. 12, pp1675-1680
(1978), Shilimkan, R. V. and Stepanek, J. B.
19 3rd Edition; McGraw-Hill, New York (1980), Treybal, R.E.
plant (before end-of-pipe scrubbers), therefore the
efficiencies in these data bases may not be
representative of low concentrations.
A1-2.2.3 Attempts at developing the empirical
database at these low concentrations suggest that actual
removal efficiencies are lower than those predicted by
most scrubber design texts.
A1-2.2.4 As a result, new scrubbers may need to have
additional packing to ensure theoretical removal
efficiencies are achieved.
A1-2.3 Rigorous custom design of a scrubber for a
particular service requires full knowledge of the
conditions that are to be encountered as well as of the
performance that is to be attained.
A1-2.3.1 Gas flow rates should normally be known
fairly accurately — at least when the plant is originally
designed.
A1-2.3.2 Concentrations of acid and caustic gases will
need to be estimated.
A1-2.3.3 Conditions to be met may be changed several
times over the probable life of the scrubbing equipment,
as changes are made in the semiconductor fabrication
processes and the exhaust system.
A1-2.3.4 Exhaust flow may also be increased, to
accommodate equipment additions, thus raising the
possibility the scrubber may become overloaded.
A1-2.4 Studies by SEMATECH indicate that the
concentration of corrosives in the exhaust entering the
end-of-pipe scrubber(s) range from <1 ppmv to as high
as 10 ppmv. Additionally, the typical scrubber with
99+ % theoretical removal efficiency was actually
achieving removal efficiencies ranging from 80%–95%.
A1-2.5 Scrubbers being applied to corrosive pollutants
are usually standardized units assembled by a number
of vendor companies. These units are designed to
handle specified ranges of gas flow, but in other
respects are not designed but simply built. If they are
packed-bed scrubbers, they are usually fitted with
standard depths of packing. The liquid flow rates can
be varied within limits; but otherwise, the performance
potentials are fixed unless there are provisions for
changing the depth of packing and perhaps the kind of
packing. Once the system is installed, such changes to
increase the efficiency will probably increase the