1、Designation: F 1396 93 (Reapproved 2005)Standard Test Method forDetermination of Oxygen Contribution by Gas DistributionSystem Components1This standard is issued under the fixed designation F 1396; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONSemiconductor clean rooms are serviced by high-purity gas distribution systems. This test
3、methodpresents a procedure that may be applied for the evaluation of one or more components considered foruse in such systems.1. Scope1.1 This test method covers a procedure for testing compo-nents for oxygen contribution to ultra-high purity gas distribu-tion systems at ambient temperature. In addi
4、tion, this testmethod allows testing of the component at elevated ambienttemperatures as high as 70C.1.2 This test method applies to in-line components contain-ing electronics grade materials such as those used in asemiconductor gas distribution system.1.3 Limitations:1.3.1 This test method is limit
5、ed by the sensitivity of currentinstrumentation, as well as the response time of the instrumen-tation. This test method is not intended to be used for testcomponents larger than 12.7-mm (12-in.) outside diameternominal size. This test method could be applied to largercomponents; however, the stated
6、volumetric flow rate may notprovide adequate mixing to ensure a representative sample.Higher flow rates may improve the mixing but excessivelydilute the sample.1.3.2 This test method is written with the assumption thatthe operator understands the use of the apparatus at a levelequivalent to six mont
7、hs of experience.1.4 The values stated in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of thi
8、s standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 6.2. Terminology2.1 Definitions:2.1.1 baselinethe instrument response under steady stateconditions.2.1.2 glove baga
9、n enclosure that contains a controlledatmosphere. A glove box could also be used for this testmethod.2.1.3 heat trace heating of a component, spool piece, ortest stand by a uniform and complete wrapping of the item withresistant heat tape.2.1.4 minimum detection limit (MDL) of the instrumentthe lowe
10、st instrument response detectable and readable by theinstrument, and at least two times the amplitude of the noise.2.1.5 response timethe time required for the system toreach steady state after a change in concentration.2.1.6 spool piecea null component, consisting of astraight piece of electropolis
11、hed tubing and appropriate fittings,used in place of the test component to establish the baseline.2.1.7 standard conditions101.3 kPa, 0.0C (14.73 psia,32F).2.1.8 test componentany device being tested, such as avalve, regulator, or filter.2.1.9 test standthe physical test system used to measureimpuri
12、ty levels.2.1.10 zero gasa purified gas that has an impurity con-centration below the MDL of the analytical instrument. Thisgas is to be used for both instrument calibration and componenttesting.2.2 Symbols:2.2.1 P1The inlet pressure measured upstream of thepurifier and filter in the test apparatus.
13、2.2.2 P2The outlet pressure measured downstream of theanalyzer in the test apparatus.2.2.3 ppbvParts per billion by volume assuming ideal gasbehavior, equivalent to nmole/mole (such as nL/L). The sameas molar parts per billion (ppb).1This test method is under the jurisdiction of ASTM Committee F01 o
14、nElectronics and is the direct responsibility of Subcommittee F01.10 on ProcessingEnvironments.Current edition approved Jan. 1, 2005. Published January 2005. Originallyapproved in 1992. Last previous edition approved in 1999 as F 1396 92(1999).1Copyright ASTM International, 100 Barr Harbor Drive, PO
15、 Box C700, West Conshohocken, PA 19428-2959, United States.2.2.4 ppbwParts per billion by weight (such as ng/g).2.2.5 ppmvParts per million by volume assuming idealgas behavior, equivalent to mole/mole (such as L/L). Thesame as molar parts per million (ppm).2.2.6 ppmwParts per million by weight (suc
16、h as g/g).2.2.7 Q1the bypass sample flow not going through theanalytical system.2.2.8 Q2the total sample flow through the analyticalsystem.2.2.9 Qsthe flow through the spool piece or component.2.2.10 Tathe temperature of the air discharged by theanalyzers cooling exhaust.2.2.11 Tsthe temperature of
17、the spool piece or component.2.2.11.1 DiscussionPrecautions must be taken to insurethat the temperature measured by the thermocouple is as closeas possible to that of the spool piece and test component.Appropriate insulation and conductive shield should be used toachieve as uniform a temperature as
18、possible. The thermo-couple must be in contact with the outside wall of thecomponent or spool piece.2.2.12 V-1, V-2inlet and outlet valves of bypass loop,respectively.2.2.13 V-3, V-4inlet and outlet valves of test loop, respec-tively.3. Significance and Use3.1 This test method defines a procedure fo
19、r testing compo-nents being considered for installation into a high-purity gasdistribution system. Application of this test method is expectedto yield comparable data among components tested for pur-poses of qualification for this installation.4. Apparatus4.1 Materials:4.1.1 Nitrogen or Argon, clean
20、 and dry, as specified in 7.5.4.1.2 Spool Piece, that can be installed in place of the testcomponent is required. This piece is to be a straight section of316L electropolished stainless steel tubing with no restrictions.The length of the spool piece shall be 200 mm. The spool piecehas the same end c
21、onnections as the test component.4.1.2.1 Components With Stub EndsUse compression fit-tings with nylon or teflon ferrules to connect the spool pieceand test component to the test loop. Keep the purged glove bagaround each component for the duration of the test. In the caseof long pieces of electropo
22、lished tubing, use two glove bags,one at each end.4.1.3 Tubing, used downstream of the test component shallbe 316L electropolished stainless steel seamless tubing. Thediameter of the sample line to the analyzer shall not be largerthan 6.4 mm (14 in.). The length of the sample line from the tee(insta
23、lled upstream of the pressure gage P2) to the analyzershall not be more than 600 mm, so as to minimize the effect(adsorption/desorption) of the sample line on the result. Thesample line shall have no more than two mechanical joints.4.1.4 Valves, diaphragm or bellows type, capable of unim-paired oper
24、ation at 94C (200F). The use of all-welded,all-metal valves is preferred.4.2 Instrumentation:4.2.1 Oxygen AnalyzerThe oxygen analyzer is to beplaced downstream of the test component. Accurate baselinereadings must be obtained prior to and subsequent to each ofthe tests. Excessive deviations in basel
25、ine levels (610 ppbv)before or after the tests require that all results be rejected. Theanalyzer must be capable of accurately recording changes inoxygen concentrations on a real time basis.4.2.2 Oxygen Analyzer CalibrationZero gas shall be at anoxygen level below the MDL of the instrument, supplied
26、 bypurified gas, with the purifier in close proximity to the analyzer.The instruments internal standard, if available, is to be usedfor the span calibration. Alternatively, span gas from a cylindermay be used.4.3 Pressure and Flow ControlUpstream pressure is to becontrolled with a regular upstream o
27、f the test component. Flowis to be controlled at a point downstream of the sampling portand monitored at that point. A mass flow controller is preferredfor maintaining the flow as described in 7.4. Sampling is to beperformed via a tee in the line, with a section of straight tubingbefore the mass flo
28、w controller. All lines must conform to4.1.3. Inlet pressure is monitored by P1. Test flow is the sum ofQ1and Q2. Q1is directly controlled, and Q2is the measuredflow through the analyzer. Refer to Fig. 1.4.4 Bypass LoopThe design of the bypass loop is notrestricted to any one design. It could be, fo
29、r example, a 3.2-mm(18-in) 316L stainless steel coil or a flexible tube section. Thisallows the flexibility necessary to install test components ofdifferent lengths.5. Hazards5.1 It is required that the user have a working knowledge ofthe respective instrumentation and that the user practice properh
30、andling of test components for trace oxygen analysis. Goodlaboratory practices must also be understood.5.2 It is required that the user be familiar with propercomponent installation, and that the test components be in-stalled on the test stand in accordance with manufacturersinstructions.5.3 Do not
31、exceed ratings (such as pressure, temperature,and flow) of component.5.4 Gloves are to be worn for all steps.5.5 Limit exposure of the instrument and test component toatmospheric contamination before and during the test.6. Calibration6.1 Calibrate instruments using standard laboratory prac-tices and
32、 manufacturers recommendations.FIG. 1 Test SchematicF 1396 93 (2005)27. Conditioning7.1 Ensure that adequate mixing of the test gas is attained.7.2 PressureTest component at 200 kPa gage (30 psig)measured at P2.7.3 Temperature Tsis to be in the ambient temperaturerange of 18 to 26C (64 to 78F) and i
33、n the higher meantemperature range of 69 to 71C (156 to 160F). Tamust notdeviate more than 6 2C (4F) from the time of calibration tothe termination of the test. Tamust either be within the rangeof 18 to 26C (64 to 78F) or be consistent with the analyticalsystems manufacturers specifications, whichev
34、er is morestringent.7.4 The flow rate Qsfor components is 1 standard L/minwith 6 2 % tolerance.7.5 The test gas shall be purified nitrogen or argon with amaximum oxygen concentration not exceeding an oxygenconcentration of 10 ppb. Gas quality must be maintained atflow specified in 7.4. The test gas
35、must be passed through afilter having a pore size rating of 0.02 m or finer. the filtermust be compatible with the 94C (200F) bake-out.8. Preparation of Apparatus8.1 A schematic drawing of a recommended test apparatuslocated inside a clean laboratory is shown in Fig. 1. Deviationsfrom this design ar
36、e acceptable as long as baseline levelsconsistent with 4.2.1 can be maintained. Nitrogen or argon gasis purified to remove water and hydrocarbons. The base gas isthen filtered by an electronics grade, high purity, point of usefilter (pore size rating # 0.02 m) before it is delivered to thetest compo
37、nent.8.2 A bypass loop may be used to divert gas flow throughthe test stand and the analyzer whenever the spool piece or atest component is installed or removed from the test stand. Thisprevents the ambient air from contaminating the test apparatusand the oxygen analyzer; thus, the analyzer baseline
38、 remainsthe same. A glove bag is used to enclose test component linesof the test apparatus during the installation and removal of thespool piece and the test piece.8.3 A trace oxygen analyzer capable of detecting oxygenconcentration levels down to 2 ppb is connected to the teststand to sample the ga
39、s flowing through the test piece. Thepurified and filtered base gas from the test stand containing 10 ppb oxygen is used as the zero oxygen gas source for theanalyzer. Since the analyzer is sensitive to the sample flow rate,the metering valves within the analyzer should be adjusted toyield the flow
40、rates required by the specification for an inletpressure of 30 psig. The gas flow rate Qsis set to 1 L/min.8.4 Inlet gas pressure is controlled by a pressure regulatorand measured immediately upstream of the purifier by anelectronic grade pressure gage. Flow measurement is carriedout by a mass flow
41、controller (MFC) located downstream of theanalyzer. The outlet pressure of the gas is measured immedi-ately downstream of the analyzer by another electronic gradepressure gage. The MFC along with its digital readout shouldbe calibrated before use to control and display the gas flow rateQ1.8.5 The te
42、mperature of the spool piece, test specimen,analyzer cell compartment, and the oxygen concentrationmeasured by the analyzer can either be recorded continuouslyby a 25 channel data logger or collected and stored in acomputer using a data acquisition program.9. Procedure (see Fig. 2)9.1 Bake-OutWith t
43、he spool piece installed and valvesV-1, V-2, V-3, and V-4 open, bake out the system (downstreamof purifier to upstream of analyzer, exclusive of the exhaustleg) at 94C (200F) until outlet oxygen concentration is stablebelow 20 ppbv. Flow of the gas is specified in 7.4. Cool tolower Ts. Close valves
44、V-1 and V-2.9.2 BaselineFlow gas through the test stand with thespool piece installed on the test stand. Use the flow rate asdefined in 7.4. Flow for 30 min after the oxygen concentrationhas attained a level of 20 ppbv. Utilizing heat tape, heat thespool piece and upstream tubing to within 80 mm of
45、theupstream valve. Monitor the oxygen of the outlet and the Ts,asspecified in 7.3. The time required to reach the higher Tsmustbe less than or equal to 10 min. Continue testing for 30 minafter a stable baseline is reestablished (20 ppbv) as specifiedin 9.1. Cool until the lower Tsis reached.9.3 Plac
46、e the spool piece, test component (in originalbagging), and fittings into a glove bag or nitrogen tent withoutdisconnecting. Purge the glove bag with approximately fiveglove bag volumes of inert gas. Disconnect the spool piecewhile maintaining the flow through the system. Maintain thespool piece in
47、the proximity of the positive flow. Reinstall thespool piece on the test stand. The entire disconnection andreinstallation must be performed within 2 min. Maintain flowthrough the analyzer during disconnection and installation viathe bypass loop, using valves V-1, V-2, V-3, and V-4 (if V-1 andV-2 ar
48、e open, then V-3 and V-4 will be closed). Duringdisconnection, open valves V-1 and V-2 first, then close V-3and V-4. After connection, reverse the order. Keep the purgedglove bag around each component for the duration of the test.In the case of long pieces of electropolished tubing, use twoglove bag
49、s, one at each end.9.4 Initiate flow through the spool piece in accordance with8.4. Monitor Tsand Tain accordance with 8.3. Monitor oxygenuntil a stable baseline, in accordance with 9.2, is reestablished(20 ppbv). Utilizing heat tape, heat the spool piece andupstream tubing to within 80 mm of the upstream valve. Turnon the current and monitor the oxygen of the outlet and the Ts,in accordance with 8.3. The time required to reach the higherTsmust be less than or equal to 10 min. Continue testing untila stable baseline is rees
