1、Designation: F 1397 93 (Reapproved 2005)Standard Test Method forDetermination of Moisture Contribution by Gas DistributionSystem Components1This standard is issued under the fixed designation F 1397; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase 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 tes
3、t 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 testing components for totalmoisture contribution to a gas distribution system at ambienttemperature. In addition, the test method allow
4、s testing atelevated ambient temperatures as high as 70C and of thecomponent moisture capacity and recovery.1.2 This test method applies to in-line components contain-ing electronics grade materials such as those used in semicon-ductor gas distribution systems.1.3 Limitations:1.3.1 This test method
5、is limited by the sensitivity of currentinstrumentation, as well as by the response time of theinstrumentation. This test method is not intended to be used fortest components larger than 12.7-mm (12-in.) outside diameternominal size. This test method could be applied to largercomponents; however, th
6、e stated 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
7、 six months 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 us
8、er of this 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 5.2. Terminology2.1 Definitions:2.1.1 baselinethe instrument response under steady stateconditions.2.1.2 g
9、love bagan 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 instrumen
10、tthe lowest 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 elec
11、tropolished 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 measu
12、reimpurity levels.2.1.10 V-1, V-2inlet and outlet valves of bypass loop,respectively.2.1.11 V-3, V-4inlet and outlet valves of test loop, respec-tively.2.1.12 zero gasa purified gas that has an impurityconcentration below the MDL of the analytical instrument.This gas is to be used for both instrumen
13、t calibration andcomponent testing.2.2 Abbreviations:Abbreviations:2.2.1 MFCmass flow controller.1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.10 on ProcessingEnvironments.Current edition approved Jan. 1, 2005. Pu
14、blished January 2005. Originallyapproved in 1992. Last previous edition approved in 1999 as F 1397 93(1999).1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.2.2 ppbvparts per billion by volume assuming ideal gasbehavior, equivalent
15、to nmole/mole (such as nL/L). The sameas molar parts per billion (ppb).2.2.3 ppbwparts per billion by weight (such as ng/g).2.2.4 ppmvparts per million by volume assuming idealgas behavior, equivalent to mole/mole (such as L/L). Thesame as molar parts per million (ppm).2.2.5 ppmwparts per million by
16、 weight (such as g/g).2.3 Symbols:2.3.1 P1The inlet pressure measured upstream of thepurifier and filter in the test apparatus.2.3.2 P2The outlet pressure measured downstream of theanalyzer in the test apparatus.2.3.3 Q1the bypass sample flow not going through theanalytical system.2.3.4 Q2the total
17、sample flow through the analyticalsystem.2.3.5 Qsthe flow through the spool piece or component.2.3.6 Tathe temperature of the air discharged by theanalyzers cooling exhaust.2.3.7 Tsthe temperature of the spool piece or component.2.3.7.1 DiscussionThe thermocouple must be in contactwith the outside w
18、all of the component or spool piece.3. Significance and Use3.1 The purpose of this test method is to define a procedurefor testing components being considered for installation into ahigh-purity gas distribution system. Application of this testmethod is expected to yield comparable data among compo-n
19、ents tested for the purposes of qualification for this installa-tion.4. Apparatus4.1 Materials:4.1.1 Nitrogen or Argon, clean, dry, as specified in 8.4.4.1.2 Spool Piece, that can be installed in place of the testcomponent is required. This piece is to be a straight section of316L electropolished st
20、ainless steel tubing with no restrictions.The length of the spool piece shall be 200 mm (0.8 in.). Thespool piece should have the same end connections as the testcomponent.4.1.3 Tubing, used downstream of the purifier shall be 316Lelectropolished stainless steel seamless tubing. The diameter ofthe s
21、ample line to the analyzer shall not be larger than 6.4 mm(14 in.). The length of the sample line from the tee (installedupstream of the pressure gage P2) to the analyzer shall not bemore than 600 mm (2.4 in.) to minimize the effect (adsorption/desorption) of the sample line on the result. The sampl
22、e lineshall have no more than two mechanical joints.4.1.3.1 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
23、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 94C (200F). The use ofall-welded, all-metal valves is preferred.4.2 Instrumentation:4.2.1 Moisture AnalyzerMoisture analyzers (such as elec-tro
24、lytic, piezo-electric, chilled mirror, or opto-electronic) areused to measure moisture levels. The analyzer is to be placeddownstream of the test component. Accurate baseline readingsmust be obtained prior to and subsequent to each of the tests.Excessive deviations in baseline levels (620 ppbv) befo
25、re orafter the tests require that all results be rejected. The analyzermust be capable of accurately recording changes in moistureconcentrations on a real time basis (see Appendix X1.1).4.2.2 Pressure and Flow ControlUpstream pressure is tobe controlled with a regular upstream of the test component.
26、Flow is to be controlled at a point downstream of the samplingport and monitored at that point. A mass flow controller ispreferred for maintaining the flow as described in 8.3. Sam-pling is to be performed via a tee in the line, with a run ofstraight tubing before the mass flow controller. All lines
27、 mustconform to 4.1.3. Inlet pressure is monitored by P1. Test flowis the sum of Q1and Q2. Q1is directly controlled, and Q2is thetotal flow through the analyzer (see Fig. 1).4.3 Bypass Loop The design of the bypass loop is notrestricted to any one design. It could be, for example, a 3.2-mm(18-in.) 3
28、16L 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 properhandling of test components
29、for trace moisture 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 exceed ratings (such as pr
30、essure, temperature,and flow) of the 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.5.6 Ensure that adequate mixing of the test gas is attained.6. Preparation of Apparatus6.1 A schematic
31、 drawing of a recommended test apparatuslocated inside a clean laboratory is shown in Fig. 1. Deviationsfrom this design are acceptable as long as baseline levelsFIG. 1 Test SchematicF 1397 93 (2005)2consistent with 9.2 can be maintained. Nitrogen or argon gas ispurified to remove water and hydrocar
32、bons. The base gas isthen filtered by an electronics grade high purity, point of usegas filter (pore size rating of #0.02 m) before it is deliveredto the test component.6.2 A bypass loop may be used to divert gas flow throughthe test stand and the analyzer whenever the spool piece or atest component
33、 is installed or removed from the test stand. Thisprevents the ambient air from contaminating the test apparatusand the moisture analyzer; thus, the analyzer baseline remainsthe same. A glove bag is used to enclose test component linesof the test apparatus during the installation and removal of thes
34、pool piece and the test piece.6.3 A moisture analyzer capable of detecting moistureconcentration levels down to 10 ppb is connected to the teststand to sample the gas flowing through the test piece. Thepurified and filtered base gas from the test stand containing 10ppb moisture is used as the zero m
35、oisture 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 rates required by the specification for an inletpressure of 30 psig. The gas flow rate Qsis set to 1 L/min.6.4 Inlet gas pressure is
36、 controlled by a pressure regulatorand measured immediately upstream of the purifier by anelectronic grade pressure gage. Flow measurement is carriedout by a mass flow controller (MFC) located downstream of theanalyzer. The outlet pressure of the gas is measured immedi-ately downstream of the analyz
37、er by another electronic gradepressure gage. The MFC along with its digital readout shouldbe calibrated before use to control and display the gas flow rateQ1.6.5 The temperature of the spool piece, test specimen,analyzer cell compartment, and the moisture concentrationmeasured by the analyzer can ei
38、ther be recorded continuouslyby a multichannel data logger or collected and stored in acomputer using a data acquisition program.6.6 A moisture generator capable of generating moistureconcentration levels over the range of 100 ppb to 2000 ppb isconnected upstream of the test component through valve
39、V-5.7. Calibration7.1 Calibrate instruments regularly in accordance withmanufacturers instructions.7.2 Moisture Analyzer CalibrationZero gas must containmoisture below the MDL of the instrument, supplied bypurified gas, with the purifier in close proximity to the analyzer.Use the instruments interna
40、l standard, if available, is to beused for the span calibration. If such a standard is not available,calibrate the analyzer with an external moisture generatoraccording to the manufacturers instructions.8. Conditioning8.1 PressureTest the test component at 200 kPa gage (30psig) as measured by P2.8.2
41、 TemperatureTsis to be in the ambient temperaturerange of 18 to 26C (64 to 78F) and the higher range of 69 to71C (156 to 160F). Tamust not deviate more than 62C(4F) from the time of calibration to the termination of the test.Tamust either be within the range of 18 to 26C (64 to 78F)or be consistent
42、with the analytical systems manufacturersspecifications, whichever is more stringent.8.3 The flow rate Qsfor components is 1 standard L/minwith 62 % tolerance.8.4 The test gas shall be purified nitrogen or argon with amaximum moisture concentration not exceeding a moistureconcentration level of 20 p
43、pb. Gas quality must be maintainedat flow specified in 8.3. The test gas must be passed through agas filter having a pore size rating of 0.02 m or finer. The filtermust be compatible with the 94C (200F) bake-out.9. Procedure (See Fig. 2)9.1 Bake-OutWith the spool piece installed and valvesV-1, V-2,
44、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 moisture concentration isstable (40 ppbv). Flow of the gas is specified in 8.3. Cool tolower Ts. Close valves V-1 and V-2.9.2 BaselineFlow gas through the te
45、st stand with thespool piece installed on the test stand. Use the flow rate asdefined in 8.3. Flow for 30 min after the moisture concentrationvalues have attained a level of 20 ppbv. Utilizing heat tape,heat the spool piece and upstream tubing to within 80 mm ofthe upstream valve. Monitor the moistu
46、re of the outlet and theTs, as specified in 8.2. The time required to reach the higher Tsmust be less than or equal to 10 min. Continue testing for 30min after a stable baseline is reestablished (40 ppbv). Cooluntil the lower Tsis reached.9.3 Place the spool piece, test component (in originalbagging
47、), 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 the proximity of the positive flow. Reinstall thespoo
48、l piece on the test stand. The entire disconnection andreinstallation must be performed within 2 min. Flow throughFIG. 2 Test Procedure SequenceF 1397 93 (2005)3the analyzer must be maintained during disconnection andinstallation via the bypass loop, using valves V-1, V-2, V-3, andV-4 (if V-1 and V-
49、2 are open, then V-3 and V-4 will be closed).During disconnection, open valves V-1 and V-2 first, then closeV-3 and V-4. After connection, reverse the order.9.4 Initiate flow in accordance with 8.3. Monitor Tsand Tain accordance with 8.2. Monitor moisture until a stablebaseline, in accordance with 9.2, is reestablished (20 ppbv).Utilizing heat tape, heat the spool piece and upstream tubing towithin 80 mm of the upstream valve. Monitor the moisture ofthe outlet and the Ts, as specified in 8.2. The time required toreach t
