ASTM F1398-93(2012)
(Test Method)Standard Test Method for Determination of Total Hydrocarbon Contribution by Gas Distribution System Components
Standard Test Method for Determination of Total Hydrocarbon Contribution by Gas Distribution System Components
SIGNIFICANCE AND USE
3.1 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 purposes of qualification for this installation.
SCOPE
1.1 This test method covers the testing of components for total hydrocarbons (THC) contribution to a gas distribution system at ambient temperature. In addition, this test method allows testing of the component at elevated ambient temperatures as high as 70°C.
1.2 This test method applies to in-line components containing electronics grade materials in the gaseous form, 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 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 Different instrumental methods (such as flame ionization detector (FID), mass spectrometer (MS)) will yield total hydrocarbon (THC) levels that are not comparable due to different sensitivities to different molecular species. Hydrocarbon contaminants of high-purity gas distribution systems can be subdivided into two general categories: ( 1) noncondensable hydrocarbons (4), that are present due to difficulty of removal and relative atmospheric abundance, and (2) condensable hydrocarbons, that are often left behind on component surfaces as residues. Condensable hydrocarbons include pump oils, degreasing agents, and polishing compound vehicles.
1.3.3 Because of the tremendous disparity of hydrocarbon species, it is suggested that direct comparisons be made only among data gathered using the same detection method.
1.3.4 This test method is intended for use by operators who understand 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 concerns, 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
Relations
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: F1398 − 93 (Reapproved 2012)
Standard Test Method for
Determination of Total Hydrocarbon Contribution by Gas
Distribution System Components
This standard is issued under the fixed designation F1398; 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 1.3.3 Because of the tremendous disparity of hydrocarbon
species, it is suggested that direct comparisons be made only
1.1 This test method covers the testing of components for
among data gathered using the same detection method.
total hydrocarbons (THC) contribution to a gas distribution
1.3.4 This test method is intended for use by operators who
system at ambient temperature. In addition, this test method
understand the use of the apparatus at a level equivalent to six
allows testing of the component at elevated ambient tempera-
months of experience.
tures as high as 70°C.
1.4 The values stated in SI units are to be regarded as the
1.2 This test method applies to in-line components contain-
standard. The inch-pound units given in parentheses are for
ing electronics grade materials in the gaseous form, such as
information only.
those used in semiconductor gas distribution systems.
1.5 This standard does not purport to address all of the
1.3 Limitations:
safety concerns, if any, associated with its use. It is the
1.3.1 Thistestmethodislimitedbythesensitivityofcurrent
responsibility of the user of this standard to establish appro-
instrumentation, as well as by the response time of the
priate safety and health practices and determine the applica-
instrumentation.This test method is not intended to be used for
bility of regulatory limitations prior to use. Specific hazard
components larger than 12.7-mm ( ⁄2-in.) outside diameter
statements are given in Section 5.
nominal size. This test method could be applied to larger
components; however, the stated volumetric flow rate may not
2. Terminology
provide adequate mixing to ensure a representative sample.
Higher flow rates may improve the mixing but excessively
2.1 Definitions:
dilute the sample. 2.1.1 baseline—the instrument response under steady state
1.3.2 Different instrumental methods (such as flame ioniza-
conditions.
tion detector (FID), mass spectrometer (MS)) will yield total
2.1.2 glove bag—an enclosure that contains a controlled
hydrocarbon (THC) levels that are not comparable due to
atmosphere. A glove box could also be used for this test
different sensitivities to different molecular species. Hydrocar-
method.
bon contaminants of high-purity gas distribution systems can
2.1.3 heat trace—heatingofcomponent,spoolpiece,ortest
be subdivided into two general categories: (1) noncondensable
stand by a uniform and complete wrapping of the item with
hydrocarbons (
resistant heat tape.
removal and relative atmospheric abundance, and (2) condens-
2.1.4 methane (CH ) equivalent—that concentration of CH
able hydrocarbons, that are often left behind on component
4 4
that causes the same instrument response as the sample.
surfaces as residues. Condensable hydrocarbons include pump
2.1.4.1 Discussion—The calibration gas contains a known
oils, degreasing agents, and polishing compound vehicles.
concentration of methane (CH ). Instrument response to zero
gas and span gas defines the calibration curve for the analyzer.
This test method is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.10 on Contamina-
Instrument response to the sample is the summation of the
tion Control.
response for each hydrocarbon reaching the detector. The
Current edition approved July 1, 2012. Published August 2012. Originally
concentration reported is the methane concentration, from the
approved in 1992. Last previous edition approved in 2005 as F1398 – 93(2005).
DOI: 10.1520/F1398-93R12. calibrationcurvethatcorrespondstotheinstrumentresponseto
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1398 − 93 (2012)
the sample. The sample’s concentration is equivalent to the 2.3.8 V-1, V-2 = inlet and outlet valves of bypass loop,
methaneconcentrationthatwouldproducethesameinstrument respectively.
response. 2.3.9 V-3, V-4 = inlet and outlet valves of test loop, respec-
tively.
2.1.5 minimumdetectionlimit(MDL)oftheinstrument—the
lowest instrument response above zero detectable that is
3. Significance and Use
readable by the instrument and at least two times the amplitude
of the noise. 3.1 The purpose of this test method is to define a procedure
for testing components being considered for installation into a
2.1.6 response time—the time required for the system to
high-purity gas distribution system. Application of this test
reach steady state after a measurable change in concentration.
method is expected to yield comparable data among compo-
2.1.7 spoolpiece—anullcomponent,consistingofastraight
nents tested for purposes of qualification for this installation.
piece of electropolished tubing and appropriate fittings, used in
place of the test component to establish the baseline.
4. Apparatus
2.1.8 standard conditions—101.3 kPa, 0.0°C (14.73 psia,
4.1 Materials:
32°F).
4.1.1 Test Gas, purified nitrogen or argon with a maximum
2.1.9 test component—any device being tested, such as a
THC concentration not exceeding the manufacturer’s stated
valve, regulator, or filter.
minimum detection limit of the instrument (MDL). Particulate
filtration of the test gas to 0.02 µm or finer is required, using a
2.1.10 test stand—the physical test system used to measure
typical electronics grade filter. The filter must be compatible
impurity levels.
with the 94°C (200°F) bake-out.
2.1.11 zero gas—a gas that has a THC concentration below
4.1.2 Spool Piece, that can be installed in place of the test
the MDLof the analytical instrument. This purified gas is used
component is required. This piece is to be a straight section of
for both instrument calibration and component testing.
316Lelectropolished stainless steel tubing with no restrictions.
2.2 Abbreviations:
Thelengthofthespoolpieceshallbe200mm.Thespoolpiece
2.2.1 FID—flame ionization detector.
shall have the same end connections as the test component.
2.2.2 MFC—mass flow controller. 4.1.2.1 Components with Stub Ends—Use compression fit-
tings with nylon or teflon ferrules to connect the spool piece
2.2.3 MS—mass spectrometer.
and test component to the test loop. Keep the purged glove bag
2.2.4 ppbv—parts per billion by volume assuming ideal gas
around each component for the duration of the test. In the case
behavior, equivalent to nmole/mole (such as nL/L).
of long pieces of electropolished tubing, use two glove bags,
2.2.4.1 Discussion—The same as molar parts per billion
one at each end.
(ppb).
4.1.3 Tubing, used downstream of the purifier shall be 316L
2.2.5 ppbw—parts per billion by weight (such as ng/g).
electropolishedstainlesssteelseamlesstubing.Thediameterof
the sample line to the analyzer shall not be larger than 6.4 mm
2.2.6 ppmv—parts per million by volume assuming ideal
( ⁄4 in.). The length of the sample line from the tee (installed
gas behavior, equivalent to µmole/mole (such as µL/L).
upstream of the pressure gage P ) to the analyzer shall not be
2.2.6.1 Discussion—The same as molar parts per million
more than 600 mm to minimize the effect (adsorption/
(ppm).
desorption) of the sample line on the result. The sample line
2.2.7 ppmw—parts per million by weight (such as µg/g).
shall have no more than two mechanical joints.
2.2.8 slpm—standard liters per minute. The gas volumetric
4.1.4 Valves, diaphragm or bellows type and must be ca-
flow rate measured in liters per minute at 0.0°C (32°F) and
pable of unimpaired operation at 94°C (200°F). The use of
101.3 kPa (1 atm).
all-welded, all-metal valves is preferred.
2.2.9 THC—total hydrocarbon.
4.2 Instrumentation:
2.3 Symbols: 4.2.1 THC Analyzer—The THC analyzer is to be placed
2.3.1 P —the inlet pressure measured upstream of the
downstream of the test component.Accurate baseline readings
purifier and filter in the test apparatus. must be obtained prior to and subsequent to each of the tests.
2.3.2 P —the outlet measured downstream of the analyzer
The baseline must return to levels <100 ppbv, before and after
in the test apparatus. the tests. Deviations greater than this require that all results be
2.3.3 Q = the bypass sample flow not going through the
rejectedandanewtestcomponentbetested.Theanalyzermust
analytical system. be capable of accurately recording changes in THC concentra-
2.3.4 Q = the total sample flow through the analytical
tions on a real-time basis, within the constraints of the data
system. acquisition system.
2.3.5 Q = the flow through the spool piece or component.
4.2.2 THC analyzer calibration—Two-point calibration,
s
2.3.6 T = the temperature of the air discharged by the zero and span, is to be performed regularly. Zero gas is defined
a
analyzer’s cooling exhaust.
as below the manufacturer’s stated MDL of the instrument,
2.3.7 T = the temperature of the spool piece or component. supplied by purified gas, with the purifier in close proximity to
s
2.3.7.1 Discussion—The thermocouple must be located in the analyzer. Span gas is analyzed at the lowest possible
contact with the outside wall of the component or spool piece. detectionrange,whichmaynotbeatthelowestdetectionrange
F1398 − 93 (2012)
oftheinstrument.Spangasis5–10ppmvmethane, 620 %for 5.1.2 It is required that the user be familiar with proper
FID. Calibration is based on traceable methane concentration component installation and that the test components be in-
in the base gas (nitrogen or argon). stalled on the test stand in accordance with manufacturer’s
4.2.3 Flame Ionization Detector (FID)—The FID detects instructions.
hydrocarbon species by ionizing the organic material in a 5.1.3 Do not exceed ratings (such as pressure, temperature,
flame. Ions produced in the hydrogen flame yield a measurable and flow) of the component.
current, directly related to the quantity of hydrocarbons intro- 5.1.4 Gloves are to be worn for all steps.
duced to the flame. Burner gases, hydrogen, and air are not to 5.1.5 Limit exposure of the instrument and test component
containmeasurableamountsofTHC.Purifiersareavailablefor to atmospheric and hydrocarbon contamination before and
this purpose (especially to remove methane). Burner gases during the test.
must be maintained at a temperature between 18 and 26°C (64 5.1.6 Precautions must be taken to insure that the tempera-
and 78°F). ture measured by the thermocouple is as close as possible to
4.2.3.1 The THC data are referred to as ppmv quantity of that of the spool piece or the test component. Use appropriate
CH equivalents, corresponding to the sum of the number of insulation and conductive shield to achieve as uniform a
equivalent carbons. Simple, low molecular weight hydrocar- temperature as possible.
bons are readily detected and quantified as total THC. Higher 5.1.7 Ensure that adequate mixing of the test gas is attained.
molecular weight hydrocarbons and more substituted hydro-
6. Preparation of Apparatus
carbons may not be detected well. The FID is, therefore, a
6.1 A schematic drawing of a recommended test apparatus
specific group detector that yields quantification of total
located inside a clean laboratory is shown in Fig. 1. Deviations
hydrocarbons for a specific detectable group.
from this design are acceptable as long as baseline levels
4.3 Pressure and Flow Control—Upstream pressure is to be
consistent with 4.2.1 can be maintained. Nitrogen or argon gas
controlled with a regulator upstream of the test component.
is purified to remove water and hydrocarbons. The base gas is
Flow is to be controlled at a point downstream of the sampling
then filtered by an electronics grade, high purity, point of use
port and monitored at that point. A mass flow controller is
gas filter (pore size rating ≤0.02 µm) before it is delivered to
preferred for maintaining the flow as described in 8.3.
the test component.
However, a variable area flowmeter plus a back pressure
6.2 A bypass loop may be used to divert gas flow through
regulator may be used instead. Sampling is to be performed via
the test stand and the analyzer whenever the spool piece or a
a tee in the line, with a run of straight tubing before the mass
testcomponentisinstalledorremovedfromtheteststand.This
flow controller. All lines must conform to 4.1.3. Inlet pressure
prevents the ambient air from contaminating the test apparatus
is monitored by P . Test flow is the sum of Q and Q . Q is
1 1 2 1
and the hydrocarbon analyzer; thus, the analyzer baseline
directly controlled, and Q is the total flow through the
remains the same. A glove bag is used to enclose test
analyzer (refer to Fig. 1).
component lines of the test apparatus during the installation
4.4 Bypass Loop—The design of the bypass loop is not
and removal of the spool piece and the test piece.
restrictedtoanyonedesign.Itcouldbe,forexample,a3.2-mm
6.3 A total hydrocarbon analyzer capable of detecting hy-
( ⁄8-in.) 316Lstainless steel coil or a flexible tube section. This
drocarbon concentration levels down to <50 ppb is connected
allows the flexibility necessary to install test components of
to the test stand to sample the gas flowing through the test
different lengths.
piece.TheTHC analyzer uses hydrogen fuel for the generation
oftheflamerequiredfortheFIDintheinstrument.Thepurified
5. Hazards
and filtered base gas from the test stand containing <10 ppb
5.1 Precautions:
THC is used as the zero gas source for the analyzer. Since the
5.1.1 It is required that the user have a working knowledge
analyzer is sensitive to the sample flow rate, the metering
of the respective instrumentation and that the user practice
valves within the analyzer should be adjusted to yield the flow
proper handling of test components for trace organic analysis.
rates required by the specification for an inlet pressure of 30
Good laboratory practices must also be understood.
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 purified by an
electronic grade pressure gage. Flow m
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.