ASTM F1398-93(1999)

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

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 (
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 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 6.

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 F1398-93(2005) - Standard Test Method for Determination of Total Hydrocarbon Contribution by Gas Distribution System Components
• Effective Date: 01-Jan-2005

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 1398–93 (Reapproved 1999)
Standard Test Method for
Determination of Total Hydrocarbon Contribution by Gas
Distribution System Components
This standard is issued under the fixed designation F 1398; 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 surfaces as residues. Condensable hydrocarbons include pump
oils, degreasing agents, and polishing compound vehicles.
1.1 This test method covers the testing of components for
1.3.3 Because of the tremendous disparity of hydrocarbon
total hydrocarbons (THC) contribution to a gas distribution
species, it is suggested that direct comparisons be made only
system at ambient temperature. In addition, this test method
among data gathered using the same detection method.
allows testing of the component at elevated ambient tempera-
1.3.4 This test method is intended for use by operators who
tures as high as 70°C.
understand the use of the apparatus at a level equivalent to six
1.2 This test method applies to in-line components contain-
months of experience.
ing electronics grade materials in the gaseous form, such as
1.4 The values stated in SI units are to be regarded as the
those used in semiconductor gas distribution systems.
standard. The inch-pound units given in parentheses are for
1.3 Limitations:
information only.
1.3.1 Thistestmethodislimitedbythesensitivityofcurrent
1.5 This standard does not purport to address all of the
instrumentation, as well as by the response time of the
safety concerns, if any, associated with its use. It is the
instrumentation.This test method is not intended to be used for
responsibility of the user of this standard to establish appro-
components larger than 12.7-mm ( ⁄2-in.) outside diameter
priate safety and health practices and determine the applica-
nominal size. This test method could be applied to larger
bility of regulatory limitations prior to use. Specific hazard
components; however, the stated volumetric flow rate may not
statements are given in Section 5.
provide adequate mixing to ensure a representative sample.
Higher flow rates may improve the mixing but excessively
2. Terminology
dilute the sample.
2.1 Definitions:
1.3.2 Different instrumental methods (such as flame ioniza-
2.1.1 baseline—the instrument response under steady state
tion detector (FID), mass spectrometer (MS)) will yield total
conditions.
hydrocarbon (THC) levels that are not comparable due to
2.1.2 glove bag—an enclosure that contains a controlled
different sensitivities to different molecular species. Hydrocar-
atmosphere. A glove box could also be used for this test
bon contaminants of high-purity gas distribution systems can
method.
be subdivided into two general categories: ( 1) noncondensable
2.1.3 heat trace— heating of component, spool piece, or
hydrocarbons ( teststandbyauniformandcompletewrappingoftheitemwith
removal and relative atmospheric abundance, and (2) condens-
resistant heat tape.
able hydrocarbons, that are often left behind on component
2.1.4 methane (CH ) equivalent—that concentration of CH
4 4
that causes the same instrument response as the sample.
2.1.4.1 Discussion—The calibration gas contains a known
This test method is under the jurisdiction of ASTM Committee F-1 on
concentration of methane (CH ). Instrument response to zero
Electronics and is the direct responsibility of Subcommittee F01.10 on Processing
gas and span gas defines the calibration curve for the analyzer.
Environments.
Instrument response to the sample is the summation of the
Current edition approved April 15, 1993. Published June 1993. Originally
published as F 1398 – 92. Last previous edition F 1398 – 92. response for each hydrocarbon reaching the detector. The
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 1398–93 (1999)
concentration reported is the methane concentration, from the 2.3.9 V-3, V-4 = inlet and outlet valves of test loop, respec-
calibrationcurvethatcorrespondstotheinstrumentresponseto tively.
the sample. The sample’s concentration is equivalent to the
3. Significance and Use
methaneconcentrationthatwouldproducethesameinstrument
3.1 The purpose of this test method is to define a procedure
response.
for testing components being considered for installation into a
2.1.5 minimum detection limit (MDL) of the instrument—
high-purity gas distribution system. Application of this test
the lowest instrument response above zero detectable that is
method is expected to yield comparable data among compo-
readable by the instrument and at least two times the amplitude
nents tested for purposes of qualification for this installation.
of the noise.
2.1.6 response time—the time required for the system to
4. Apparatus
reach steady state after a measurable change in concentration.
4.1 Materials:
2.1.7 spool piece—a null component, consisting of a
4.1.1 Test Gas, purified nitrogen or argon with a maximum
straightpieceofelectropolishedtubingandappropriatefittings,
THC concentration not exceeding the manufacturer’s stated
used in place of the test component to establish the baseline.
minimum detection limit of the instrument (MDL). Particulate
2.1.8 standard conditions—101.3 kPa, 0.0°C (14.73 psia,
filtration of the test gas to 0.02 µm or finer is required, using a
32°F).
typical electronics grade filter. The filter must be compatible
2.1.9 test component—any device being tested, such as a
with the 94°C (200°F) bake-out.
valve, regulator, or filter.
4.1.2 Spool Piece, that can be installed in place of the test
2.1.10 test stand—the physical test system used to measure
component is required. This piece is to be a straight section of
impurity levels.
316Lelectropolished stainless steel tubing with no restrictions.
2.1.11 zero gas—a gas that has a THC concentration below
Thelengthofthespoolpieceshallbe200mm.Thespoolpiece
the MDLof the analytical instrument. This purified gas is used
shall have the same end connections as the test component.
for both instrument calibration and component testing.
4.1.2.1 Components with Stub Ends—Use compression fit-
2.2 Abbreviations: Abbreviations:
tings with nylon or teflon ferrules to connect the spool piece
2.2.1 FID—flame ionization detector.
and test component to the test loop. Keep the purged glove bag
2.2.2 MFC—mass flow controller.
around each component for the duration of the test. In the case
2.2.3 MS—mass spectrometer.
of long pieces of electropolished tubing, use two glove bags,
2.2.4 ppbv—parts per billion by volume assuming ideal gas
one at each end.
behavior, equivalent to nmole/mole (such as nL/L).
4.1.3 Tubing, used downstream of the purifier shall be 316L
2.2.4.1 Discussion—The same as molar parts per billion
electropolishedstainlesssteelseamlesstubing.Thediameterof
(ppb).
the sample line to the analyzer shall not be larger than 6.4 mm
2.2.5 ppbw—parts per billion by weight (such as ng/g).
( ⁄4 in.). The length of the sample line from the tee (installed
2.2.6 ppmv—parts per million by volume assuming ideal
upstream of the pressure gage P ) to the analyzer shall not be
gas behavior, equivalent to µmole/mole (such as µL/L).
more than 600 mm to minimize the effect (adsorption/
2.2.6.1 Discussion—The same as molar parts per million
desorption) of the sample line on the result. The sample line
(ppm).
shall have no more than two mechanical joints.
2.2.7 ppmw—parts per million by weight (such as µg/g).
4.1.4 Valves, diaphragm or bellows type and must be ca-
2.2.8 slpm—standard liters per minute. The gas volumetric
pable of unimpaired operation at 94°C (200°F). The use of
flow rate measured in liters per minute at 0.0°C (32°F) and
all-welded, all-metal valves is preferred.
101.3 kPa (1 atm).
4.2 Instrumentation:
2.2.9 THC—total hydrocarbon.
4.2.1 THC Analyzer— The THC analyzer is to be placed
2.3 Symbols:
downstream of the test component.Accurate baseline readings
2.3.1 P —the inlet pressure measured upstream of the
must be obtained prior to and subsequent to each of the tests.
purifier and filter in the test apparatus.
The baseline must return to levels <100 ppbv, before and after
2.3.2 P —the outlet measured downstream of the analyzer
the tests. Deviations greater than this require that all results be
in the test apparatus.
rejectedandanewtestcomponentbetested.Theanalyzermust
2.3.3 Q = the bypass sample flow not going through the
1 be capable of accurately recording changes in THC concentra-
analytical system.
tions on a real-time basis, within the constraints of the data
2.3.4 Q = the total sample flow through the analytical
2 acquisition system.
system.
4.2.2 THC analyzer calibration—Two-point calibration,
2.3.5 Q = the flow through the spool piece or component.
s zero and span, is to be performed regularly. Zero gas is defined
2.3.6 T = the temperature of the air discharged by the
as below the manufacturer’s stated MDL of the instrument,
a
analyzer’s cooling exhaust.
supplied by purified gas, with the purifier in close proximity to
2.3.7 T = the temperature of the spool piece or component.
the analyzer. Span gas is analyzed at the lowest possible
s
2.3.7.1 Discussion—The thermocouple must be located in
detectionrange,whichmaynotbeatthelowestdetectionrange
contact with the outside wall of the component or spool piece. oftheinstrument.Spangasis5–10ppmvmethane, 620 %for
2.3.8 V-1, V-2 = inlet and outlet valves of bypass loop, FID. Calibration is based on traceable methane concentration
respectively. in the base gas (nitrogen or argon).
F 1398–93 (1999)
4.2.3 Flame Ionization Detector (FID)—The FID detects 5.1.3 Do not exceed ratings (such as pressure, temperature,
hydrocarbon species by ionizing the organic material in a and flow) of the component.
flame. Ions produced in the hydrogen flame yield a measurable 5.1.4 Gloves are to be worn for all steps.
current, directly related to the quantity of hydrocarbons intro- 5.1.5 Limit exposure of the instrument and test component
duced to the flame. Burner gases, hydrogen, and air are not to
to atmospheric and hydrocarbon contamination before and
containmeasurableamountsofTHC.Purifiersareavailablefor during the test.
this purpose (especially to remove methane). Burner gases
5.1.6 Precautions must be taken to insure that the tempera-
must be maintained at a temperature between 18 and 26°C (64 ture measured by the thermocouple is as close as possible to
and 78°F).
that of the spool piece or the test component. Use appropriate
4.2.3.1 The THC data are referred to as ppmv quantity of insulation and conductive shield to achieve as uniform a
CH equivalents, corresponding to the sum of the number of
temperature as possible.
equivalent carbons. Simple, low molecular weight hydrocar-
5.1.7 Ensure that adequate mixing of the test gas is attained.
bons are readily detected and quantified as total THC. Higher
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. How-
the test component.
ever, a variable area flowmeter plus a back pressure regulator
6.2 A bypass loop may be used to divert gas flow through
may be used instead. Sampling is to be performed via a tee in
the test stand and the analyzer whenever the spool piece or a
the line, with a run of straight tubing before the mass flow
testcomponentisinstalledorremovedfromtheteststand.This
controller. All lines must conform to 4.1.3. Inlet pressure is
prevents the ambient air from contaminating the test apparatus
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
5.1.2 It is required that the user be familiar with proper
6.4 Inlet gas pressure is controlled by a pressure regulator
component installation and that the test components be in-
and measured immediately upstream of the purified by an
stalled on the test stand in accordance with manufacturer’s
electronic grade pressure gage. Flow measurement is carried
instructions.
o
...