ASTM F1397-93(1999)

Standard Test Method for Determination of Moisture Contribution by Gas Distribution System Components

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.

General Information

• Status: Historical
• Publication Date: 09-Jun-1999
• ICS: 23.040.01 - Pipeline components and pipelines in general
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.10 - Contamination Control

Relations

• Replaced By: ASTM F1397-93(2005) - Standard Test Method for Determination of Moisture Contribution by Gas Distribution System Components
• Effective Date: 10-Jun-1999

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F 1397–93 (Reapproved 1999)
Standard Test Method for
Determination of Moisture Contribution by Gas Distribution
System Components
This standard is issued under the fixed designation F 1397; 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 (e) 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 2. Terminology
1.1 This test method covers testing components for total 2.1 Definitions:
moisture contribution to a gas distribution system at ambient 2.1.1 baseline—the instrument response under steady state
temperature. In addition, the test method allows testing at conditions.
elevated ambient temperatures as high as 70°C and of the 2.1.2 glove bag—an enclosure that contains a controlled
component moisture capacity and recovery. atmosphere. A glove box could also be used for this test
1.2 This test method applies to in-line components contain- method.
ing electronics grade materials such as those used in semicon- 2.1.3 heat trace— heating of a component, spool piece, or
ductor gas distribution systems. teststandbyauniformandcompletewrappingoftheitemwith
1.3 Limitations: resistant heat tape.
1.3.1 Thistestmethodislimitedbythesensitivityofcurrent 2.1.4 minimum detection limit (MDL) of the instrument—
instrumentation, as well as by the response time of the the lowest instrument response detectable and readable by the
instrumentation.This test method is not intended to be used for instrument and at least two times the amplitude of the noise.
test components larger than 12.7-mm ( ⁄2-in.) outside diameter 2.1.5 response time—the time required for the system to
nominal size. This test method could be applied to larger reach steady state after a change in concentration.
components; however, the stated volumetric flow rate may not 2.1.6 spool piece—a null component, consisting of a
provide adequate mixing to ensure a representative sample. straightpieceofelectropolishedtubingandappropriatefittings,
Higher flow rates may improve the mixing but excessively used in place of the test component to establish the baseline.
dilute the sample. 2.1.7 standard conditions—101.3 kPa, 0.0°C (14.73 psia,
1.3.2 This test method is written with the assumption that 32°F).
the operator understands the use of the apparatus at a level 2.1.8 test component—any device being tested, such as a
equivalent to six months of experience. valve, regulator, or filter.
1.4 The values stated in SI units are to be regarded as the 2.1.9 test stand—the physical test system used to measure
standard. The inch-pound units given in parentheses are for impurity levels.
information only. 2.1.10 V-1, V-2—inlet and outlet valves of bypass loop,
1.5 This standard does not purport to address all of the respectively.
safety concerns, if any, associated with its use. It is the 2.1.11 V-3, V-4—inlet and outlet valves of test loop, respec-
responsibility of the user of this standard to establish appro- tively.
priate safety and health practices and determine the applica- 2.1.12 zero gas—a purified gas that has an impurity
bility of regulatory limitations prior to use. Specific hazard concentration below the MDL of the analytical instrument.
statements are given in Section 5. This gas is to be used for both instrument calibration and
component testing.
2.2 Abbreviations:Abbreviations:
This test method is under the jurisdiction of ASTM Committee F-1 on
2.2.1 MFC—mass flow controller.
Electronics and is the direct responsibility of Subcommittee F01.10 on Processing
Environments.
Current edition approved April 15, 1993. Published June 1993. Originally
published as F 1397 – 92. Last previous edition F 1397 – 92.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 1397–93 (1999)
2.2.2 ppbv—parts per billion by volume assuming ideal gas 4.2.1 Moisture Analyzer—Moisture analyzers (such as elec-
behavior, equivalent to nmole/mole (such as nL/L). The same trolytic, piezo-electric, chilled mirror, or opto-electronic) are
as molar parts per billion (ppb). used to measure moisture levels. The analyzer is to be placed
2.2.3 ppbw—parts per billion by weight (such as ng/g). downstream of the test component.Accurate baseline readings
2.2.4 ppmv—parts per million by volume assuming ideal must be obtained prior to and subsequent to each of the tests.
gas behavior, equivalent to µmole/mole (such as µL/L). The Excessive deviations in baseline levels (620 ppbv) before or
same as molar parts per million (ppm). after the tests require that all results be rejected. The analyzer
2.2.5 ppmw—parts per million by weight (such as µg/g). must be capable of accurately recording changes in moisture
2.3 Symbols: concentrations on a real time basis (see Appendix X1.1).
2.3.1 P —The inlet pressure measured upstream of the 4.2.2 Pressure and Flow Control—Upstream pressure is to
purifier and filter in the test apparatus. be controlled with a regular upstream of the test component.
2.3.2 P —The outlet pressure measured downstream of the Flow is to be controlled at a point downstream of the sampling
analyzer in the test apparatus. port and monitored at that point. A mass flow controller is
2.3.3 Q —the bypass sample flow not going through the preferred for maintaining the flow as described in 8.3. Sam-
analytical system. pling is to be performed via a tee in the line, with a run of
2.3.4 Q —the total sample flow through the analytical straight tubing before the mass flow controller. All lines must
system. conform to 4.1.3. Inlet pressure is monitored by P . Test flow
2.3.5 Q —the flow through the spool piece or component. is the sum of Q and Q . Q is directly controlled, and Q is the
s 1 2 1 2
2.3.6 T —the temperature of the air discharged by the total flow through the analyzer (see Fig. 1).
a
analyzer’s cooling exhaust. 4.3 Bypass Loop— The design of the bypass loop is not
2.3.7 T —the temperature of the spool piece or component. restrictedtoanyonedesign.Itcouldbe,forexample,a3.2-mm
s
2.3.7.1 Discussion—The thermocouple must be in contact ( ⁄8-in.) 316Lstainless steel coil, or a flexible tube section.This
with the outside wall of the component or spool piece. allows the flexibility necessary to install test components of
different lengths.
3. Significance and Use
5. Hazards
3.1 The purpose of this test method is to define a procedure
for testing components being considered for installation into a
5.1 It is required that the user have a working knowledge of
high-purity gas distribution system. Application of this test
the respective instrumentation and that the user practice proper
method is expected to yield comparable data among compo-
handling of test components for trace moisture analysis. Good
nents tested for the purposes of qualification for this installa-
laboratory practices must also be understood.
tion.
5.2 It is required that the user be familiar with proper
component installation and that the test components be in-
4. Apparatus
stalled on the test stand in accordance with manufacturer’s
4.1 Materials:
instructions.
4.1.1 Nitrogen or Argon, clean, dry, as specified in 8.4.
5.3 Do not exceed ratings (such as pressure, temperature,
4.1.2 Spool Piece, that can be installed in place of the test
and flow) of the component.
component is required. This piece is to be a straight section of
5.4 Gloves are to be worn for all steps.
316Lelectropolished stainless steel tubing with no restrictions.
5.5 Limit exposure of the instrument and test component to
The length of the spool piece shall be 200 mm (0.8 in.). The
atmospheric contamination before and during the test.
spool piece should have the same end connections as the test
5.6 Ensure that adequate mixing of the test gas is attained.
component.
4.1.3 Tubing, used downstream of the purifier shall be 316L
6. Preparation of Apparatus
electropolishedstainlesssteelseamlesstubing.Thediameterof
6.1 A schematic drawing of a recommended test apparatus
the sample line to the analyzer shall not be larger than 6.4 mm
located inside a clean laboratory is shown in Fig. 1. Deviations
( ⁄4 in.). The length of the sample line from the tee (installed
from this design are acceptable as long as baseline levels
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.
4.1.3.1 Components With Stub Ends—Use compression fit-
tings with nylon or teflon ferrules to connect the spool piece
and test component to the test loop. Keep the purged glove bag
around each component for the duration of the test. In the case
of long pieces of electropolished tubing, use two glove bags,
one at each end.
4.1.4 Valves, must be diaphragm or bellows type and ca-
pable of unimpaired operation at 94°C (200°F). The use of
all-welded, all-metal valves is preferred.
4.2 Instrumentation: FIG. 1 Test Schematic
F 1397–93 (1999)
consistent with 9.2 can be maintained. Nitrogen or argon gas is or be consistent with the analytical systems manufacturer’s
purified to remove water and hydrocarbons. The base gas is specifications, whichever is more stringent.
then filtered by an electronics grade high purity, point of use 8.3 The flow rate Q for components is 1 standard L/min
s
gas filter (pore size rating of#0.02 µm) before it is delivered with 62 % tolerance.
to the test component. 8.4 The test gas shall be purified nitrogen or argon with a
6.2 A bypass loop may be used to divert gas flow through maximum moisture concentration not exceeding a moisture
the test stand and the analyzer whenever the spool piece or a concentration level of 20 ppb. Gas quality must be maintained
testcomponentisinstalledorremovedfromtheteststand.This at flow specified in 8.3. The test gas must be passed through a
prevents the ambient air from contaminating the test apparatus gasfilterhavingaporesizeratingof0.02µmorfiner.Thefilter
and the moisture analyzer; thus, the analyzer baseline remains must be compatible with the 94°C (200°F) bake-out.
the same. A glove bag is used to enclose test component lines
9. Procedure (See Fig. 2)
of the test apparatus during the installation and removal of the
spool piece and the test piece.
9.1 Bake-Out—With the spool piece installed and valves
6.3 A moisture analyzer capable of detecting moisture V-1, V-2, V-3, and V-4 open, bake out the system (downstream
concentration levels down to 10 ppb is connected to the test
of purifier to upstream of analyzer, exclusive of the exhaust
stand to sample the gas flowing through the test piece. The
leg) at 94°C (200°F) until outlet moisture concentration is
purifiedandfilteredbasegasfromtheteststandcontaining<10
stable (<40 ppbv). Flow of the gas is specified in 8.3. Cool to
ppb moisture is used as the zero moisture gas source for the
lower T . Close valves V-1 and V-2.
s
analyzer.Sincetheanalyzerissensitivetothesampleflowrate,
9.2 Baseline—Flow gas through the test stand with the
the metering valves within the analyzer should be adjusted to
spool piece installed on the test stand. Use the flow rate as
yield the flow rates required by the specification for an inlet
definedin8.3.Flowfor30minafterthemoistureconcentration
pressure of 30 psig. The gas flow rate Q is set to 1 L/min.
values have attained a level of <20 ppbv. Utilizing heat tape,
s
6.4 Inlet gas pressure is controlled by a pressure regulator
heat the spool piece and upstream tubing to within 80 mm of
and measured immediately upstream of the purifier by an
the upstream valve. Monitor the moisture of the outlet and the
electronic grade pressure gage. Flow measurement is carried
T , as specified in 8.2. The time required to reach the higher T
s s
outbyamassflowcontroller(MFC)locateddownstreamofthe
must be less than or equal to 10 min. Continue testing for 30
analyzer. The outlet pressure of the gas is measured immedi- min after a stable baseline is reestablished (<40 ppbv). Cool
ately downstream of the analyzer by another electronic grade
until the lower T is reached.
s
pressure gage. The MFC along with its digital readout should 9.3 Place the spool piece, test component (in original
be calibrated before use to control and display the gas flow rate
bagging), and fittings into a glove bag or nitrogen tent without
Q . disconnecting. Purge the glove bag with approximately five
6.5 The temperature of the spool piece, test specimen,
glove bag volumes of inert gas. Disconnect the spool piece
analyzer cell compartment, and the moisture concentration while maintaining the flow through the system. Maintain the
measured by the analyzer can either be recorded continuously
spool piece in the proximity of the positive flow. Reinstall the
by a multichannel data logger or collected and stored in a
spool piece on the test stand. The entire disconnection and
computer using a data acquisition program.
reinstallation must be performed within 2 min. Flow through
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.
7.2 Moisture Analyzer Calibration—Zero gas must contain
moisture below the MDL of the instrument, supplied by
purifiedgas,withthepurifierincloseproximitytotheanalyzer.
Use the instrument’s internal standard, if available, is to be
usedforthespancalibration.Ifsuchastandardisnotavailable,
calibrate the analyzer with an external moisture generator
according to the manufacturer’s instructions.
8. Conditioning
8.1 Pressure—Test the test component at 200 kPa gage (30
psig) as measured by P .
8.2 Temperature—T is to be in the ambient temperature
s
range of 18 to 26°C (64 to 78°F) and the higher range of 69 to
71°C (156 to 160°F). T must not deviate more than 62°C
a
(4°F) from the time of calibration to the termination of the test.
T must either be within the range of 18 to 26°C (64 to 78°F) FIG. 2 Test Procedure Sequence
a
F 1397–93 (1999)
the analyzer must be maintained during disconnection and 9.10 Utilizing heat tape, heat the test component and up-
installationviathebypassloop,usingvalvesV-1,V-2,V-3,and stream tubing to withi
...