ASTM F1397-93(2005)
(Test Method)Standard Test Method for Determination of Moisture Contribution by Gas Distribution System Components
Standard Test Method for Determination of Moisture Contribution by Gas Distribution System Components
SIGNIFICANCE AND USE
The purpose of this test method is to define a procedure for testing components being considered for installation into a high-purity gas distribution system. Application of this test method is expected to yield comparable data among components tested for the purposes of qualification for this installation.
SCOPE
1.1 This test method covers testing components for total moisture contribution to a gas distribution system at ambient temperature. In addition, the test method allows testing at elevated ambient temperatures as high as 70°C and of the component moisture capacity and recovery.
1.2 This test method applies to in-line components containing electronics grade materials such as those used in semiconductor gas distribution systems.
1.3 Limitations:
1.3.1 This test method is limited by the sensitivity of current instrumentation, as well as by the response time of the instrumentation. This test method is not intended to be used for test components larger than 12.7-mm ( 1/2-in.) outside diameter nominal size. This test method could be applied to larger components; however, the stated volumetric flow rate may not provide adequate mixing to ensure a representative sample. Higher flow rates may improve the mixing but excessively dilute the sample.
1.3.2 This test method is written with the assumption that the operator understands the use of the apparatus at a level equivalent to six months of experience.
1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.
1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 5.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F1397 − 93(Reapproved 2005)
Standard Test Method for
Determination of Moisture Contribution by Gas Distribution
System Components
This standard is issued under the fixed designation F1397; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Semiconductor clean rooms are serviced by high-purity gas distribution systems. This test method
presents a procedure that may be applied for the evaluation of one or more components considered for
use in such systems.
1. Scope bility of regulatory limitations prior to use. Specific hazard
statements are given in Section 5.
1.1 This test method covers testing components for total
moisture contribution to a gas distribution system at ambient
2. Terminology
temperature. In addition, the test method allows testing at
elevated ambient temperatures as high as 70°C and of the
2.1 Definitions:
component moisture capacity and recovery.
2.1.1 baseline—the instrument response under steady state
1.2 This test method applies to in-line components contain-
conditions.
ing electronics grade materials such as those used in semicon-
2.1.2 glove bag—an enclosure that contains a controlled
ductor gas distribution systems.
atmosphere. A glove box could also be used for this test
1.3 Limitations:
method.
1.3.1 Thistestmethodislimitedbythesensitivityofcurrent
2.1.3 heat trace— heating of a component, spool piece, or
instrumentation, as well as by the response time of the
teststandbyauniformandcompletewrappingoftheitemwith
instrumentation.This test method is not intended to be used for
resistant heat tape.
test components larger than 12.7-mm ( ⁄2-in.) outside diameter
nominal size. This test method could be applied to larger
2.1.4 minimum detection limit (MDL) of the instrument—the
components; however, the stated volumetric flow rate may not
lowest instrument response detectable and readable by the
provide adequate mixing to ensure a representative sample.
instrument and at least two times the amplitude of the noise.
Higher flow rates may improve the mixing but excessively
2.1.5 response time—the time required for the system to
dilute the sample.
reach steady state after a change in concentration.
1.3.2 This test method is written with the assumption that
the operator understands the use of the apparatus at a level
2.1.6 spoolpiece—anullcomponent,consistingofastraight
equivalent to six months of experience.
piece of electropolished tubing and appropriate fittings, used in
1.4 The values stated in SI units are to be regarded as the
place of the test component to establish the baseline.
standard. The inch-pound units given in parentheses are for
2.1.7 standard conditions—101.3 kPa, 0.0°C (14.73 psia,
information only.
32°F).
1.5 This standard does not purport to address all of the
2.1.8 test component—any device being tested, such as a
safety concerns, if any, associated with its use. It is the
valve, regulator, or filter.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
2.1.9 test stand—the physical test system used to measure
impurity levels.
This test method is under the jurisdiction of ASTM Committee F01 on
2.1.10 V-1, V-2—inlet and outlet valves of bypass loop,
Electronics and is the direct responsibility of Subcommittee F01.10 on Contamina-
respectively.
tion Control.
Current edition approved Jan. 1, 2005. Published January 2005. Originally
2.1.11 V-3, V-4—inlet and outlet valves of test loop, respec-
approved in 1992. Last previous edition approved in 1999 as F1397 – 93(1999).
DOI: 10.1520/F1397-93R05. tively.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1397 − 93 (2005)
2.1.12 zero gas—a purified gas that has an impurity concen- 4.1.3.1 Components With Stub Ends—Use compression fit-
tration below the MDLof the analytical instrument.This gas is tings with nylon or teflon ferrules to connect the spool piece
to be used for both instrument calibration and component and test component to the test loop. Keep the purged glove bag
testing. around each component for the duration of the test. In the case
of long pieces of electropolished tubing, use two glove bags,
2.2 Abbreviations:
one at each end.
2.2.1 MFC—mass flow controller.
4.1.4 Valves, must be diaphragm or bellows type and ca-
2.2.2 ppbv—parts per billion by volume assuming ideal gas
pable of unimpaired operation at 94°C (200°F). The use of
behavior, equivalent to nmole/mole (such as nL/L). The same
all-welded, all-metal valves is preferred.
as molar parts per billion (ppb).
4.2 Instrumentation:
2.2.3 ppbw—parts per billion by weight (such as ng/g).
4.2.1 Moisture Analyzer—Moisture analyzers (such as elec-
2.2.4 ppmv—parts per million by volume assuming ideal
trolytic, piezo-electric, chilled mirror, or opto-electronic) are
gas behavior, equivalent to µmole/mole (such as µL/L). The
used to measure moisture levels. The analyzer is to be placed
same as molar parts per million (ppm).
downstream of the test component.Accurate baseline readings
2.2.5 ppmw—parts per million by weight (such as µg/g). must be obtained prior to and subsequent to each of the tests.
Excessive deviations in baseline levels (620 ppbv) before or
2.3 Symbols:
after the tests require that all results be rejected. The analyzer
2.3.1 P —The inlet pressure measured upstream of the
must be capable of accurately recording changes in moisture
purifier and filter in the test apparatus.
concentrations on a real time basis (see Appendix X1.1).
2.3.2 P —The outlet pressure measured downstream of the
4.2.2 Pressure and Flow Control—Upstream pressure is to
analyzer in the test apparatus.
be controlled with a regular upstream of the test component.
2.3.3 Q —the bypass sample flow not going through the
Flow is to be controlled at a point downstream of the sampling
analytical system.
port and monitored at that point. A mass flow controller is
preferred for maintaining the flow as described in 8.3. Sam-
2.3.4 Q —the total sample flow through the analytical
pling is to be performed via a tee in the line, with a run of
system.
straight tubing before the mass flow controller. All lines must
2.3.5 Q —the flow through the spool piece or component.
s
conform to 4.1.3. Inlet pressure is monitored by P . Test flow
2.3.6 T —the temperature of the air discharged by the
a
is the sum of Q and Q . Q is directly controlled, and Q is the
1 2 1 2
analyzer’s cooling exhaust.
total flow through the analyzer (see Fig. 1).
2.3.7 T —the temperature of the spool piece or component.
s
4.3 Bypass Loop— The design of the bypass loop is not
2.3.7.1 Discussion—The thermocouple must be in contact
restrictedtoanyonedesign.Itcouldbe,forexample,a3.2-mm
with the outside wall of the component or spool piece.
( ⁄8-in.)316Lstainlesssteelcoil,oraflexibletubesection.This
allows the flexibility necessary to install test components of
3. Significance and Use
different lengths.
3.1 The purpose of this test method is to define a procedure
5. Hazards
for testing components being considered for installation into a
high-purity gas distribution system. Application of this test
5.1 It is required that the user have a working knowledge of
method is expected to yield comparable data among compo-
the respective instrumentation and that the user practice proper
nents tested for the purposes of qualification for this installa-
handling of test components for trace moisture analysis. Good
tion.
laboratory practices must also be understood.
5.2 It is required that the user be familiar with proper
4. Apparatus
component installation and that the test components be in-
4.1 Materials:
stalled on the test stand in accordance with manufacturer’s
4.1.1 Nitrogen or Argon, clean, dry, as specified in 8.4.
instructions.
4.1.2 Spool Piece, that can be installed in place of the test
component is required. This piece is to be a straight section of
316Lelectropolished stainless steel tubing with no restrictions.
The length of the spool piece shall be 200 mm (0.8 in.). The
spool piece should have the same end connections as the test
component.
4.1.3 Tubing, used downstream of the purifier shall be 316L
electropolishedstainlesssteelseamlesstubing.Thediameterof
the sample line to the analyzer shall not be larger than 6.4 mm
( ⁄4 in.). The length of the sample line from the tee (installed
upstream of the pressure gage P ) to the analyzer shall not be
more than 600 mm (2.4 in.) to minimize the effect (adsorption/
desorption) of the sample line on the result. The sample line
shall have no more than two mechanical joints. FIG. 1 Test Schematic
F1397 − 93 (2005)
5.3 Do not exceed ratings (such as pressure, temperature, 7.2 Moisture Analyzer Calibration —Zero gas must contain
and flow) of the component. moisture below the MDL of the instrument, supplied by
purifiedgas,withthepurifierincloseproximitytotheanalyzer.
5.4 Gloves are to be worn for all steps.
Use the instrument’s internal standard, if available, is to be
5.5 Limit exposure of the instrument and test component to usedforthespancalibration.Ifsuchastandardisnotavailable,
atmospheric contamination before and during the test.
calibrate the analyzer with an external moisture generator
according to the manufacturer’s instructions.
5.6 Ensure that adequate mixing of the test gas is attained.
8. Conditioning
6. Preparation of Apparatus
8.1 Pressure—Test the test component at 200 kPa gage (30
6.1 A schematic drawing of a recommended test apparatus
psig) as measured by P .
located inside a clean laboratory is shown in Fig. 1. Deviations
8.2 Temperature—T is to be in the ambient temperature
s
from this design are acceptable as long as baseline levels
range of 18 to 26°C (64 to 78°F) and the higher range of 69 to
consistent with 9.2 can be maintained. Nitrogen or argon gas is
71°C (156 to 160°F). T must not deviate more than 62°C
a
purified to remove water and hydrocarbons. The base gas is
(4°F) from the time of calibration to the termination of the test.
then filtered by an electronics grade high purity, point of use
T must either be within the range of 18 to 26°C (64 to 78°F)
a
gas filter (pore size rating of#0.02 µm) before it is delivered
or be consistent with the analytical systems manufacturer’s
to the test component.
specifications, whichever is more stringent.
6.2 A bypass loop may be used to divert gas flow through
8.3 The flow rate Q for components is 1 standard L/min
s
the test stand and the analyzer whenever the spool piece or a
with 62 % tolerance.
testcomponentisinstalledorremovedfromtheteststand.This
8.4 The test gas shall be purified nitrogen or argon with a
prevents the ambient air from contaminating the test apparatus
maximum moisture concentration not exceeding a moisture
and the moisture analyzer; thus, the analyzer baseline remains
concentration level of 20 ppb. Gas quality must be maintained
the same. A glove bag is used to enclose test component lines
at flow specified in 8.3. The test gas must be passed through a
of the test apparatus during the installation and removal of the
gasfilterhavingaporesizeratingof0.02µmorfiner.Thefilter
spool piece and the test piece.
must be compatible with the 94°C (200°F) bake-out.
6.3 A moisture analyzer capable of detecting moisture
concentration levels down to 10 ppb is connected to the test
9. Procedure (See Fig. 2)
stand to sample the gas flowing through the test piece. The
9.1 Bake-Out—With the spool piece installed and valves
purifiedandfilteredbasegasfromtheteststandcontaining<10
V-1, V-2, V-3, and V-4 open, bake out the system (downstream
ppb moisture is used as the zero moisture gas source for the
of purifier to upstream of analyzer, exclusive of the exhaust
analyzer.Sincetheanalyzerissensitivetothesampleflowrate,
leg) at 94°C (200°F) until outlet moisture concentration is
the metering valves within the analyzer should be adjusted to
stable (<40 ppbv). Flow of the gas is specified in 8.3. Cool to
yield the flow rates required by the specification for an inlet
lower T . Close valves V-1 and V-2.
s
pressure of 30 psig. The gas flow rate Q is set to 1 L/min.
s
6.4 Inlet gas pressure is controlled by a pressure regulator
and measured immediately upstream of the purifier by an
electronic grade pressure gage. Flow measurement is carried
outbyamassflowcontroller(MFC)locateddownstreamofthe
analyzer. The outlet pressure of the gas is measured immedi-
ately downstream of the analyzer by another electronic grade
pressure gage. The MFC along with its digital readout should
be calibrated before use to control and display the gas flow rate
Q .
6.5 The temperature of the spool piece, test specimen,
analyzer cell compartment, and the moisture concentration
measured by the analyzer can either be recorded continuously
by a multichannel data logger or collected and stored in a
computer using a data acquisition program.
6.6 A moisture generator capable of generating moisture
concentration levels over the range of 100 ppb to 2000 ppb is
connected upstream of the test component through valve V-5.
7. Calibration
7.1 Calibrate instruments regularly in accordance with
manufacturer’s instructions. FIG. 2 Test Procedure Sequence
F1397 − 93 (2005)
9.2 Baseline—Flowgasthroughtheteststandwiththespool continuouslywithvalvesV-1andV-2duringdisconnectionand
piece installed on the test stand. Use the flow rate as defined in installation. Remove the test component caps and install the
8.3. Flow for 30 min after the moisture concentration values testcomponent.OpenV-3andV-4first,thencloseV-1andV-2.
have attained a level of <20 ppbv. Utilizing heat tape, heat the The time from disconnection of the spool piece to installation
spool piece and upstream tubing to within 80 mm of the of the test component must be less than 2 min.
upstream valve. Monitor the moisture of the outlet and the T ,
s
NOTE 2—The installation conditions of the test component, as well as
as specified in 8.2. The time required to reach the higher T
s
glove bag conditions, must be the same as the installation conditions for
must be less than or equal to 10 min. Continue testing for 30
the spool piece outlined in 9.2, including time to disconnect and connect.
min after a stable baseline is reestablished (<40 ppbv). Cool The spool piece must not be removed from the glove bag for the duration
of the test.
until the lower T is reached.
s
9.8.1 When testing valves, MFCs, and regulators, with
9.3 Place th
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