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Background Statement for SEMI Draft Document 4652A
REVISION TO SEMI C3.2-0301
SPECIFICATION FOR ARSINE (AsH3) IN CYLINDERS, 99.94% QUALITY
Note: This background statement is not part of the balloted item. It is provided solely to assist the recipient in reaching an informed decision based on the rationale of the activity that preceded the creation of this document.
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SEMI C3.2-0301was due for 5 year review. The document was reviewed and modified to bring up to current guidelines and specifications. .
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Note: Additions are indicated by underline and deletions are indicated by strikethrough.
SEMI Draft Document 4652A
REVISION TO SEMI C3.2-0301
SPECIFICATION FOR ARSINE (AsH3) IN CYLINDERS, 99.94% QUALITY
1Purpose
1.1The purpose of this document is to provide specifications for arsine (AsH3) that is used in the semiconductor industry.
2Scope
2.1This document covers requirements for arsine used in the semiconductor industry.
NOTICE: SEMI Standards and Safety Guidelines do not purport to address all safety issues associated with their use. It is the responsibility of the users of the documents to establish appropriate safety and health practices, and determine the applicability of regulatory or other limitations prior to use.
13Description
3.1 Arsine is a highly toxic, flammable, colorless gas with a disagreeable garlic-like odor. It is a hemolytic poison.
4Referenced Standards and Documents
4.1SEMI Standard
SEMI C3 — Specifications for Gases
NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.
5 Terminology
5.1Terminology appropriate to this standard is defined in SEMI C3.
26SpecificationsProperties of Arsine
Table 1 Properties of Arsine (for information only)
Metric Units / US UnitsMolecular Formula / AsH3 / AsH3
CAS Number / 7784-42-1 / 7784-42-1
Molecular weight / 77.946 / 77.946
Boiling point at 1 atm / -62.48°C / -80.46°F
Density of gas at 20°C (68°F) and 1 atm / 3.243 kg/m3 / 0.202 lb/ft3
Specific gravity of gas at 21.1°C (70°F) and 1 atm (air = 1) / 2.695 / 2.695
Density of liquid at B.P. / 1653 kg/m3 / 103.96 lb/ft3
37Requirements
Table 2 Impurity Limits for Arsine, QUALITY: 99.94%
Grade / 99.94%Impurities / Maximum Acceptable Level (ppm) #1
(See NOTE 1.)
Carbon monoxide and carbon dioxide (CO + CO2) / 2
Hydrocarbons (methane (CH4),
ethane (C2H6), ethylene (C2H4), and acetylene (C2H2)) / 1
Hydrogen (H2) / 500
Hydrogen Sulfide (H2S) / 1
Nitrogen (N2) / 10
Oxygen (O2) + Argon (Ar) / 5
Phosphine (PH3) / 10
Water (H2O) / 4
TOTAL LISTED IMPURITIES / 533
Metals — See NOTE 2.
Particles — See NOTE 2.
NOTE #1: An analysis of significant figures has not been considered. The number of significant figures will be based on analytical accuracy and the precision of the provided procedure.
NOTE 2: To be determined between supplier and user.
48 Analytical Procedures
4.18.1 Carbon Monoxide, Carbon Dioxide, and Hydrocarbons (methane, ethane, ethylene, acetylene) — This procedure is for the determination of carbon monoxide, carbon dioxide, and hydrocarbons in arsine using a gas chromatograph with a methanizer and a flame ionization detector. (See Note 1 and Figure 1.)
4.1.18.1.1 Detection Limit — 0.1 ppm each impurity.
4.1.28.1.2 Instrument Parameters
4.1.2.18.1.2.1 Column: Porapak® QS, 3.5 m (12 ft) by 2 mm ID (1/8 in OD) ss or equivalent.
4.1.2.28.1.2.2Carrier Flow: 35 mL/min helium.
4.1.2.38.1.2.3Support Gases: Set the flow rates as specified by the instrument manufacturer. If not specified, recommended flow rates are set as followings:
- Hydrogen:30 mL/min added to the carrier gas between the column outlet and the methanizer inlet.
- Air: 500 mL/min.
4.1.2.48.1.2.4 Temperatures:
- Detector:110°C
- Injector:40°C
- Oven:40°C
- Methanizer:370–400°C
4.1.2.58.1.2.5 Sample Volume: 3 mL.
4.1.38.1.3 Calibration Standards — 1–10 4 ppm each: carbon monoxide, 1-4 ppm carbon dioxide, 1-2 ppm methane, 1-2 ppm ethane, 1-2 ppm ethylene, and 1-2 ppm acetylene; balance helium.
4.1.48.1.4Calibration Standards — 1–4 ppm each: carbon monoxide, carbon dioxide, methane, ethane, ethylene, and acetylene; balance helium.
4.1.68.1.5 Operating Procedure
4.1.6.18.1.5.1 Inject the calibration standard into the column using a gas sampling valve. Record retention times and peak areas. Order of elution is carbon monoxide, methane, carbon dioxide, acetylene, ethylene, ethane.
4.1.6.28.1.5.2 Inject the sample to be tested in same manner as the calibration standard. Vent the arsine after the ethane peak. Record the retention times and peak areas.
4.1.6.38.1.5.3 Repeat 48.1.4.1.
4.1.6.48.1.5.4 Compare the average peak areas of the calibration standard to those of the arsine sample being tested. Calculate the concentration of each impurity, using the formula below. The results may not exceed specifications in §Section2 7 of this Standard.
(1)
4.28.2 Phosphine — This procedure is for the determination of phosphine in arsine using a gas chromatograph with a thermal conductivity detector.
4.2.18.2.1 Detection Limit — 5 ppm (mol/mol).
4.2.28.2.2 Instrument Parameters
4.2.2.18.2.2.1 Column: Porapak® QS, 3.5 m (12 ft) by 2 mm ID (1/8 in OD) ss or equivalent.
4.2.2.28.2.2.2Carrier Flow: 35 mL/min helium.
4.2.2.38.2.2.3Temperatures:
- Detector:80°C
- Injector:40°C
- Oven:40°C
4.2.2.48.2.2.4 Sample Volume: 3 mL.
4.2.38.2.3 Calibration Standard — 10–50 20 ppm (mol/mol) phosphine, balance helium.
4.2.48.2.4 Operating Procedure
4.2.4.18.2.4.1 Inject the calibration standard into the column using a gas sampling valve. Record the retention time and peak area.
4.2.4.28.2.4.2 Inject the sample being tested in same manner as the calibration standard. Record the retention time and peak area.
4.2.4.38.2.4.3 Repeat 48.2.4.1.
4.2.4.48.2.4.4 Compare the average peak area of the calibration standard to that of the arsine sample being tested. Calculate the concentration of phosphine, using the formula below. The result may not exceed the specification in §Section2 7 of this Standard.
(2)
4.38.3 Hydrogen, Nitrogen and Oxygen + Argon — This procedure is for the determination of hydrogen, nitrogen, oxygen + argon in arsine using a gas chromatograph with a helium ionization detector.
4.3.18.3.1 Detection Limits — 100 ppb (mol/mol) hydrogen, 100 ppb oxygen + argon, 500 ppb nitrogen.
4.3.28.3.2 Instrument Parameters
4.3.2.18.3.2.1 Columns:
- Column 1:Porapak® QS, 2.5 m (8 ft) by 3.2 mm (1/8 in) ID ss or equivalent
- Column 2:Molecular Sieve 5A, 3 m (10 ft) by 3.2 mm ID ss or equivalent.
4.3.2.28.3.2.2Carrier Flow: 25 mL/min helium.
4.3.2.38.3.2.3Temperatures:
- Detector:10°C
- Injector:30°C
- Oven:30°C
4.3.2.48.3.2.4 Sample Volume: 3 mL.
4.3.38.3.3 Calibration Standard — 1–10 ppm nitrogen, 1–10 ppm oxygen, 1–10 ppm argon, 10–100 ppm hydrogen, balance helium.
4.3.48.3.4 Operating Procedure
4.3.4.18.3.4.1 Determination of the backflush time: Inject a methane sample (1–1000 ppm, balance helium) using a 10 port gas valve and backflush at different times. Select the backflush time so that the methane peak is split by the backflush.
4.3.4.28.3.4.2 Inject the calibration standard into the column using the same gas valve. Backflush at the time determined in 48.3.4.1 and record retention times and peak areas. Order of elution is hydrogen, oxygen + argon and nitrogen.
4.3.4.38.3.4.3 Inject the sample being tested in same manner as the calibration standard. Record the retention times and peak areas.
4.3.4.48.3.4.4 Repeat 48.3.4.2.
4.3.4.58.3.4.5 Compare the average peak areas of the calibration standard to those of the arsine sample being tested. Calculate the concentration of each impurity, using the formula below. The results may not exceed the specifications in §Section2 7 of this Standard.
(3)
4.48.4 Hydrogen Sulfide — This procedure is for the determination of hydrogen sulfide in arsine using gas a chromatograph with a flame photometric detector.
4.4.18.4.1 Detection Limit — 0.1 ppm (mol/mol).
4.4.28.4.2 Instrument Parameters
4.4.2.18.4.2.1 Column: Porapak® QS 3.5 m (12 ft) by 2 mm ID (1/8 in OD) ss or equivalent.
4.4.2.28.4.2.2Carrier Flow: 35 mL/min helium. Set the flow rates as specified by the instrument manufacturer. If not specified, recommended flow rates are set as followings:
4.4.2.38.4.2.3 Support Gases:
- Hydrogen:30 – 40 mL/min.
- Air: 300 – 400 mL/min.
4.4.2.48.4.2.4 Temperatures:
- Detector:75°C
- Injector:40°C
- Oven:40°C
4.4.2.58.4.2.5 Sample Volume: 1.5 mL.
4.4.38.4.3 Calibration Standard — 1–10 2 ppm hydrogen sulfide, balance helium.
4.4.48.4.4 Operating Procedure
4.4.4.18.4.4.1 Inject the calibration standard into the column using a gas sampling valve. Record retention time and peak area.
4.4.4.28.4.4.2 Inject the sample being tested in the same manner as the calibration standard. Vent before arsine peak is eluted using same configuration as in Figure 1.
4.4.4.38.4.4.3 Repeat 48.4.4.1
4.4.4.48.4.4.4 Compare the average peak area of the calibration standard to those of the arsine sample being tested. Calculate the concentration of the hydrogen sulfide, using the formula below. The result may not exceed the specification in Section 2 7 of this Standard.
(4)
4.58.5 Water — This procedure is for the determination of moisture in arsine using continuous flow electrolysis of water in a phosphorus pentoxide (P2O5) cell.
4.5.18.5.1 Detection Limit — 1 ppm (vol/vol).
4.5.28.5.2 Instrument Parameters
4.5.2.18.5.2.1 Flow Requirements — Set the sample flow rate and pressure in accordance with manufacturer’s instructions.
4.5.38.5.3 Calibration Standards — Construct a calibration curve which contains at least three points covering the range of interest. Verify the standards employed independently on a condensation dewpoint/frostpoint hygrometer.
4.5.48.5.4 Operating Procedure
4.5.4.18.5.4.1 Obtain representative sample of gas to be analyzed and direct to unit as with the standards.
4.5.4.28.5.4.2 Determine the moisture content in the sample gas by comparing the indicated concentration with the calibration curve constructed in 48.5.3. The result may not exceed the specification in §Section 2 7 of this Standard.
NOTE 1:Carrier gases should contain less than 0.1 ppm (mol/mol) carbon monoxide and less than 0.1 ppm (mol/mol) carbon dioxide.
Figure 1
G. C. Configuration
NOTICE:This specification does not purport to address safety issues, if any, associated with its use. It is the responsibility of the user of this specification to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. SEMI makes no warranties or representations as to the suitability of the specification set forth herein for any particular application. The determination of the suitability of the specification is solely the responsibility of the user. Users are cautioned to refer to manufacturer’s instructions, product labels, product data sheets, and other relevant literature respecting any materials or equipment mentioned herein. This specification are subject to change without notice.
The user’s attention is called to the possibility that compliance with this specification may require use of copyrighted material or of an invention covered by patent rights. By publication of this specification, SEMI takes no position respecting the validity of any patent rights or copyrights asserted in connection with any item mentioned in this specification. Users of this specification are expressly advised that determination of any such patent rights or copyrights, and the risk of infringement of such rights, are entirely their own responsibility.
This is a draft document of the SEMI International Standards program. No material on this page is to be construed as an official or adopted standard. Permission is granted to reproduce and/or distribute this document, in whole or in part, only within the scope of SEMI International Standards committee (document development) activity. All other reproduction and/or distribution without the prior written consent of SEMI is prohibited.
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