Background Statement for Ratification Ballot of SEMI Draft...

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 or Safety Guideline. 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.

Doc. R5673C SEMI

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DRAFT Document Number: R5673C

Date: 7/27/2015

Background Statement for Ratification Ballot of SEMI Draft Document R5673C

Revision to SEMI C3.34-1109, Specification for Disilane (Si2H6) in Cylinders, 97% Quality

Notice: 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.

Notice: Recipients of this Document are invited to submit, with their comments, notification of any relevant

patented technology or copyrighted items of which they are aware and to provide supporting documentation. In this

context, “patented technology” is defined as technology for which a patent has issued or has been applied for. In the

latter case, only publicly available information on the contents of the patent application is to be provided.

Notice: This Document was approved with additional technical change(s) during adjudication of Letter Ballot #

5673C by the North America Chapter of the Gases Global Technical Committee during its meeting on 7/14/2015.

This Ratification Ballot is issued in order to satisfy the conditions for Letter Ballot approval by the Gases Global

Technical Committee in accordance with § 9.7.2 of the Regulations. If the Ratification Ballot voting response meets

the minimum acceptance conditions per Regulations § 10, then it will be automatically published.

One copy of the revised Draft Document is included to show the intended final published version. Only these

proposed additional technical changes are shown in the other copy of the Draft Document with revision markups

showing these intended changes, as an aid to the voter. Additions are indicated by underline and deletions are

indicated by strikethrough.

Contents for vote are limited to only considering these proposed additional technical changes. All content for a new

Standard and Safety Guideline or all proposed technical and editorial changes for revisions of Standards and Safety

Guidelines that were included in the original Letter Ballot and passed TC Chapter review, including the ones passed

with editorial changes, are incorporated, without revision markups, in both copies. All other editorial changes, if

any, made and approved during the TC Chapter review are incorporated also, without revision markups, in both

copies.

Background

The following is the complete list of the new proposed technical change(s) with their justifications:

Technical changes:

1. ¶ 6.1, Table 1, first column, last row: Delete “(excluding chloride, chromium, iron and nickel)” and

therefore footnote 2.

o Justification: Cr, Fe, and Ni have been removed from Table 1. The parenthetical note “excluding

chlorides” should also be removed because chlorosilanes is a specification with a maximum of 5

ppm.

2. ¶ 8.1, NOTE 3: Change to ¶ 8.1.4.5.

o Justification: Per the Procedure Manual ¶ 3.2.4, Notes are not an official part of a Standard and are

intended as supplementary information that is useful, but not essential or required to use a Standard.

This alternate measurement technique is intended to be allowed.

3. ¶ 8.1.2.1/Fig. 1: Insert “Ethylvinylbenzene-divinylbenzene” before “porous polymer absorbent” in ¶

8.1.2.1 and change “Porous polymer absorbent” to “Analytical Column” in Fig. 1.

o Justification: “Porous polymer absorbent” is not a sufficiently specific statement of the packing for

the method to be reproducible after “Porapak QS” was removed during this revision.


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4. ¶ 8.2.2.1: Insert “Ethylvinylbenzene-divinylbenzene” before “porous polymer absorbent”.



5. ¶ 8.3.2.1: Insert “Ethylvinylbenzene-divinylbenzene” before “porous polymer absorbent”.



6. ¶ 8.5, NOTE 5: Change to ¶ 8.5.2.4.

o Justification: Per the Procedure Manual ¶ 3.2.4, Notes are not an official part of a Standard and are

intended as supplementary information that is useful, but not essential or required to use a Standard.

This alternate measurement technique is intended to be allowed.

If this Ratification Ballot fails, the voting results will be reviewed at the meetings indicated in the table below to

determine a new course of action. Check www.semi.org/standards under Calendar of Events for the latest update.

Review Information

Task Force Review Committee Adjudication

Group: Gases Specifications Task Force NA Gases TC Chapter

Date: Monday, November 2, 2015 Tuesday, November 3, 2015

Time & Time Zone: 1:00 PM to 2:00 PM, US Pacific Time 9:00 AM to 12:00 Noon, US Pacific Time

Location: SEMI Headquarters in conjunction

with the Fall NA Standards Meetings

SEMI Headquarters in conjunction

with the Fall NA Standards Meetings

City, State/Country: San Jose, California/USA San Jose, California/USA

Leader(s): Mark Ripkowski (CONSCI) Tim Volin (Parker Hannifin)

Mohamed Saleem (Fujikin)

Standards Staff: David Bouldin

972.965.0340

[email protected]

David Bouldin

972.965.0340

[email protected]

This meeting’s details are subject to change, and additional review sessions may be scheduled if necessary. Contact

the task force leaders or Standards staff for confirmation.

Telephone and web information will be distributed to interested parties as the meeting date approaches. If you will not

be able to attend these meetings in person but would like to participate by telephone/web, please contact Standards staff.

http://www.semi.org/standards

mailto:[email protected]

mailto:[email protected]


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SEMI Draft Document R5673C

Revision to SEMI C3.34-1109, Specification for Disilane (Si2H6) in

Cylinders, 97% Quality

*Copy with Technical Change Markup*

1 Purpose

1.1 The purpose of this Document is to provide a specification for disilane (Si2H6) used in the semiconductor industry.

2 Scope

2.1 This Document covers requirements for disilane (Si2H6) used in the semiconductor industry.

2.2 If analytical methods are not complete, the requirements are presented as a guide.

NOTICE: This standard does not purport to address safety issues, if any, associated with its use. It is the responsibility of

the users of this standard to establish appropriate safety and health practices and determine the applicability of

regulatory or other limitations prior to use.

3 Description

3.1 Disilane is a pyrophoric, flammable, noncorrosive, colorless gas. It is a powerful irritant.

4 Referenced Standards and Documents

4.1 SEMI Standards

SEMI C3 — Specifications for Gases

4.2 Other References

Bogaert, R.J., Rocheleau, R. E., and Baron, B. N., “Gas Chromatographic Determination of Silanes” J. of Chrom.

Science Vol. 24 (March 1986)

NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.

5 Terminology

5.1 Terminology appropriate to this Standard is defined in SEMI C3.


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6 Specifications

6.1 Purity: The impurity limits are shown in Table 1.

Table 1 Impurity Limits for 97% Disilane

Impurities Maximum Acceptable Level (ppm)#1

Argon (Ar) + Oxygen (O2) 1

Carbon dioxide (CO2) 1

Carbon monoxide (CO) 1

Chlorosilanes (Total hydrolizable chlorides, reported as [Cl-]) 5

Disiloxane (H3SiOSiH3) 5

Hydrogen (H2) 500

Monoethylsilane 50

Nitrogen (N2) 10

Silane (SiH4) 2.5%

Total methane, ethane, propane 10

Total trisilane and tetrasilane 500

Water (H2O) 1

TOTAL SPECIFIED IMPURITIES

(excluding chloride, chromium, iron and nickel)

2.6084%

#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 test methods.

6.2 This specification applies to the gas phase of the cylinder as received.

7 Properties of Disilane (for information only)

Table 2 Properties of Disilane

Metric Units US Units

Molecular Formula Si2H6 Si2H6

CAS Number 1590-87-0 1590-87-0

Molecular weight 62.22 62.22

Boiling point at 1 atm −14.8°C 5.4°F

Freezing point −132.5°C −206.5°F

Vapor density (air = 1) 2.38 2.38

8 Test Methods for Determining Concentrations

8.1 Carbon Monoxide and Carbon Dioxide — This method is for the determination of carbon monoxide and

carbon dioxide in disilane using a gas chromatograph with a methanizer and a flame ionization detector. (See

Figure 1, Notes 1 and 2.)

NOTE 1: An optional temperature ramping during vent will shorten the analysis time.

NOTE 2: Carrier gases should contain less than 0.1 ppm carbon monoxide and less than 0.1 ppm carbon dioxide.

NOTE 3: Other accepted instrument techniques such as helium ionization detector may be used.

8.1.1 Detection Limit — 0.1 ppm for each impurity.

8.1.2 Instrument Parameters


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8.1.2.1 Column — Ethylvinylbenzene-divinylbenzene porous polymer absorbent, 3 m (10 ft.) by 1.6 mm (1/16 in.)

ID ss or equivalent.

8.1.2.2 Carrier Flow — 30 mL/min helium.

8.1.2.3 Sample Volume — 1.5 mL.

8.1.2.4 Support Gases — As specified by the instrument manufacturer.

8.1.2.4.1 Hydrogen — 20–30 mL per min added to the carrier gas between the column outlet and the methanizer inlet.

8.1.2.4.2 Air — 500 mL/min.

8.1.2.5 Temperatures

Detector — 110°C

Injector — 60°C

Oven — 60°C

Methanizer — 370°C–400°C

8.1.3 Calibration Standards — 1–10 ppm carbon monoxide, 1–10 ppm carbon dioxide, balance helium.

8.1.4 Operating Method

8.1.4.1 Inject the calibration standard into the column using a gas sampling valve. Record the retention times and

peak areas. The order of elution is carbon monoxide, carbon dioxide.

8.1.4.2 Inject the sample to be tested in same manner as the calibration standard and vent after elution of carbon

dioxide is completed, in case any silane is present. Record the retention times and peak areas.

8.1.4.3 Repeat ¶ 8.1.4.1.

8.1.4.4 Compare the average peak areas of the calibration standard to that of the disilane sample being tested.

Calculate the concentrations of carbon monoxide and carbon dioxide using the formula below. The results may not

exceed the specifications in § 6 of this Standard.

Sample Peak Area

Concentration

Concentration (1)

Standard Peak Area of Standard of Sample

8.1.4.5 Other accepted instrument techniques such as helium ionization detector may be used.

8.2 Methane, Ethane, Propane, and Silane — This method is for the determination of hydrocarbons (methane,

ethane, and propane) and silane in disilane using a gas chromatograph with a thermal conductivity detector.

8.2.1 Detection Limit — 3 ppm for each impurity.





8.2.2.3 Sample Volume — 1 mL.


Detector — 80°C

Injector — 60°C

Oven — 60°C

8.2.3 Calibration Standards — 10–50 ppm methane, 5–10 ppm ethane, 5–10 ppm propane, 0.1%–1% silane, balance

helium.



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peak areas. Order of elution is methane, silane, ethane, propane.

8.2.4.2 Inject the sample to be tested in same manner as the calibration standard. Record the retention times and peak

areas.

8.2.4.3 Repeat ¶ 8.2.4.1.


Calculate the concentrations of methane, silane, ethane, and propane, using the formula below.

Sample Peak Area

Concentration

Concentration (2)


8.3 Hydrogen, Nitrogen, and Argon — This method is for the determination hydrogen, nitrogen, and argon in disilane

using a gas chromatograph with a helium ionization detector.

8.3.1 Detection Limit — 100 ppb for hydrogen and argon, 500 ppb for nitrogen.


8.3.2.1 Columns

Column 1 — Ethylvinylbenzene-divinylbenzene porous polymer absorbent,

2.5 m (8 ft.) by 3.2 mm (1/8 in.) OD ss or equivalent.

Column 2 — 5 Å molecular sieve, 3 m (10 ft.) by 3.2 mm (1/8 in.) OD ss or equivalent.




Detector — 100°C

Injector — 30°C

Oven — 30°C

8.3.3 Calibration Standards — 1–10 ppm nitrogen, 1–10 ppm argon, 10–100 ppm hydrogen, balance helium.

8.3.4 Operating Procedure

8.3.4.1 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.

8.3.4.2 Inject the calibration standard into the column using a gas sampling valve. Backflush at the time determined

in ¶ 8.3.4.1. Record retention times and peak areas. Order of elution is hydrogen, argon, nitrogen.

8.3.4.3 Inject the sample to be tested in same manner as the calibration standard. Backflush at the time determined in

¶ 8.3.4.1. Record the retention times and peak areas.

8.3.4.4 Repeat ¶ 8.3.4.2.


Calculate the concentrations of hydrogen, nitrogen, and argon using the formula below.

Sample Peak Area

Concentration

Concentration (3)


8.4 Disiloxane, Monoethylsilane, Trisilane, and Tetrasilanes — This method is for the determination of disiloxane,

monoethylsilane, trisilane, and tetrasilanes in disilane using a gas chromatograph with a thermal conductivity

detector.


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8.4.1 Detection Limits — 5 ppm for disiloxane and 10 ppm for each of the other impurities.


8.4.2.1 Column — 30% DC 200 on Chromosorb® P, 80/100 mesh, 10 m (33 ft.) by 3.2 mm (1/8 in.) ss or equivalent.




Detector — 120°C

Injector — 60°C

Oven — 60°C for 25 min then 10°C/min to 120°C

8.4.3 Calibration Standard — 100 ppm each of trisilane, i-tetrasilane, and n-tetrasilane, and 10 ppm each disiloxane

and monoethylsilane in helium. If one or several components cannot be obtained, use a 100 ppm monosilane standard

and apply the following correction factors (CFs) using the formula below (see Reference 1):

Trisilane CF = 0.54

i-tetrasilane CF = 0.42

n-tetrasilane CF = 0.41

Correction factors for disiloxane and monoethylsilane are not available. Use the same as disilane CF = 0.69 concentration

of impurity = calculated concentration, using silane standard, × CF.


8.4.4.1 Inject the calibration standard into the column using a gas sampling valve. Record retention times and peak

areas. Order of elution is disiloxane, disilane, monoethylsilane, trisilane, i-tetrasilane, and n-tetrasilane.

8.4.4.2 Inject the sample to be tested in same manner as calibration standard. Record the retention times and peak

areas.

8.4.4.3 Repeat ¶ 8.4.4.1.


Calculate the concentrations of disiloxane, disilane, monoethylsilane, trisilane, i-tetrasilane, and n-tetrasilane, using

the formula below. If necessary, correct the results using the specified CFs in ¶ 8.4.3.

Sample Peak Area

Concentration

Concentration (4)


8.5 Water — This method is for the determination of moisture in disilane using a continuous flow electrolysis

of water in a phosphorus pentoxide (P2O5) cell.

NOTE 4: Direct gases for moisture measurement to the analyzer with stainless steel lines which have been purged.

NOTE 5: Other accepted instrument techniques such as FTIR (Fourier Transform Infrared) may be used.

8.5.1 Flow Requirement — Set the sample flow rate and pressure in accordance with manufacturer’s instructions.


8.5.2.1 Direct samples of three standards, independently verified with a moisture analyzer capable of measuring

1 ppm. After a stable reading is obtained, record the instrument’s response to each standard.

8.5.2.2 Obtain a representative sample of the gas to be analyzed and direct it to the unit as with the standards. After

a stable reading is obtained, record the instrument’s response.

8.5.2.3 Construct calibration curve from the standard data and determine the moisture content in sample gas.

8.5.2.4 Other accepted instrument techniques such as FTIR (Fourier Transform Infrared) may be used.

8.6 Total Chlorides — This method is for the determination of total hydrolyzable chlorides in disilane by titration

of a hydrolyzed sample of disilane (see Figure 2).


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8.6.1.1 Equipment

1. Safety purge regulator with proper fittings.

2. Flow meter capable of measuring 0.25 standard liters per minute (0.5 SCF/hour).

3. One cylinder of nitrogen with regulator.

4. One ice bath.

5. Three magnetic stirring bars.

6. Two 2000 mL heavy-duty sidearm flasks.

7. One #9 one-hole rubber stopper.

8. One #9 two-hole rubber stopper.

9. Two borosilicate glass tubes with fritted cylinders.

10. One gas washing bottle with fritted cylinder, 125 mL cap.

11. One buret, 50 mL capacity with PTFE stopcock.

12. One buret stand.

13. Miscellaneous clamps, support stands, and rubber hose.

14. Two 250 mL Erlenmeyer flasks.

8.6.2 Reagents

1. Potassium hydroxide flakes, technical.

2. Mercuric nitrate crystal.

3. Sodium chloride crystal.

4. Diphenyl carbazone.

5. Bromophenol blue.

6. Nitric acid.

7. Ethanol, denatured.


8.6.3.1 Fill each 2000 mL sidearm flask with about 1700 mL of 15% potassium hydroxide solution (15 g KOH per

each 100 mL water).

8.6.3.2 Fill the gas washing bottle with about 75 mL of deionized water that has been degassed.

8.6.3.3 Assemble apparatus as shown in Diagram A and purge entire system with nitrogen for 30 minutes.

8.6.3.4 Pass 30 liters (approximately one cubic foot) of disilane through the system at a rate of 0.25 liters per minute.

Record the volume of the disilane sample.

8.6.3.5 Stop disilane flow and purge system for 30 minutes.

8.6.3.6 Remove gas washing bottle from system and transfer contents quantitatively and with the aid of three 25 mL

deionized water washings, to a 250 mL Erlenmeyer flask.

8.6.3.7 Add a few drops of indicator solution (5 g diphenyl carbazone plus 0.5 g bromophenol blue dissolved in

750 mL ethanol, plus 250 mL deionized water).

8.6.3.8 Add, in a drop-wise fashion, sufficient 0.2N HNO3 (13 mL conc. HNO3, diluted to 1 L in deionized water) in

order to just turn the solution to yellow from purple.


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8.6.3.9 Titrate with a solution of 5 g. mercuric nitrate Hg(NO3)2, (diluted to 1000 mL in deionized water; then

50 mL diluted to 500 mL in deionized water) which has been previously standardized to 5.0 mL of a sodium chloride

solution (approximately 165 ng NaCl, accurately weighed, dissolved in 100 mL deionized water).

8.6.4 Calibration

8.6.4.1 Run titration blank consisting of 150 mL deionized water.

8.6.4.2 Calculate the concentration of chloride, using the formula below.

mL sample - mL blank

wt. of NaCl (g)

mL standard - mL blank 100.0 mL

60.66% Cl-

1000 mL

0.005 L

1000% NaCl 1 L 35.453 g/mole

0.082 atm L/mole K

294.26K

1 atm volume of gas samples

1 ×106 ppm = ppm Cl - (5)

8.6.5 Final Calculation — Convert the results from ppm to ppm-wt using the formula below.

ppm- wt = ppm mole/mole35.45

62.22 (6)

Analytical Column


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Figure 1

G.C. Configuration

#1 Bleed nitrogen into system at a gentle rate.

#2 Stirrers should turn at a moderate rate.

Figure 2

Chloride Scrubbing Apparatus

NOTICE: SEMI makes no warranties or representations as to the suitability of the standard(s) set forth herein for any

particular application. The determination of the suitability of the standard(s) 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. These standards are subject to change without

notice.

By publication of this standard, Semiconductor Equipment and Materials International (SEMI) takes no position

respecting the validity of any patent rights or copyrights asserted in connection with any item mentioned in this

standard. Users of this standard 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.

Si2H

6


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SEMI Draft Document R5673C Revision to SEMI C3.34-1109, Specification for Disilane (Si2H6) in Cylinders, 97% Quality

*Copy of Intended Final Published Version*

1 Purpose

1.1 The purpose of this Document is to provide a specification for disilane (Si2H6) used in the semiconductor industry.

2 Scope

2.1 This Document covers requirements for disilane (Si2H6) used in the semiconductor industry.

2.2 If analytical methods are not complete, the requirements are presented as a guide.

NOTICE: This standard does not purport to address safety issues, if any, associated with its use. It is the responsibility of

the users of this standard to establish appropriate safety and health practices and determine the applicability of

regulatory or other limitations prior to use.

3 Description

3.1 Disilane is a pyrophoric, flammable, noncorrosive, colorless gas. It is a powerful irritant.

4 Referenced Standards and Documents

4.1 SEMI Standards

SEMI C3 — Specifications for Gases

4.2 Other References

Bogaert, R.J., Rocheleau, R. E., and Baron, B. N., “Gas Chromatographic Determination of Silanes” J. of Chrom.

Science Vol. 24 (March 1986)

NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.

5 Terminology

5.1 Terminology appropriate to this Standard is defined in SEMI C3.


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6 Specifications

6.1 Purity: The impurity limits are shown in Table 1.

Table 1 Impurity Limits for 97% Disilane

Impurities Maximum Acceptable Level (ppm)#1

Argon (Ar) + Oxygen (O2) 1

Carbon dioxide (CO2) 1

Carbon monoxide (CO) 1

Chlorosilanes (Total hydrolizable chlorides, reported as [Cl-]) 5

Disiloxane (H3SiOSiH3) 5

Hydrogen (H2) 500

Monoethylsilane 50

Nitrogen (N2) 10

Silane (SiH4) 2.5%

Total methane, ethane, propane 10

Total trisilane and tetrasilane 500

Water (H2O) 1

TOTAL SPECIFIED IMPURITIES 2.6084%

#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 test methods.

6.2 This specification applies to the gas phase of the cylinder as received.

7 Properties of Disilane (for information only)

Table 2 Properties of Disilane

Metric Units US Units

Molecular Formula Si2H6 Si2H6

CAS Number 1590-87-0 1590-87-0

Molecular weight 62.22 62.22

Boiling point at 1 atm −14.8°C 5.4°F

Freezing point −132.5°C −206.5°F

Vapor density (air = 1) 2.38 2.38

8 Test Methods for Determining Concentrations

8.1 Carbon Monoxide and Carbon Dioxide — This method is for the determination of carbon monoxide and

carbon dioxide in disilane using a gas chromatograph with a methanizer and a flame ionization detector. (See

Figure 1, Notes 1 and 2.)

NOTE 1: An optional temperature ramping during vent will shorten the analysis time.

NOTE 2: Carrier gases should contain less than 0.1 ppm carbon monoxide and less than 0.1 ppm carbon dioxide.

8.1.1 Detection Limit — 0.1 ppm for each impurity.






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8.1.2.3 Sample Volume — 1.5 mL.

8.1.2.4 Support Gases — As specified by the instrument manufacturer.

8.1.2.4.1 Hydrogen — 20–30 mL per min added to the carrier gas between the column outlet and the methanizer inlet.

8.1.2.4.2 Air — 500 mL/min.


Detector — 110°C

Injector — 60°C

Oven — 60°C

Methanizer — 370°C–400°C

8.1.3 Calibration Standards — 1–10 ppm carbon monoxide, 1–10 ppm carbon dioxide, balance helium.



peak areas. The order of elution is carbon monoxide, carbon dioxide.

8.1.4.2 Inject the sample to be tested in same manner as the calibration standard and vent after elution of carbon

dioxide is completed, in case any silane is present. Record the retention times and peak areas.

8.1.4.3 Repeat ¶ 8.1.4.1.


Calculate the concentrations of carbon monoxide and carbon dioxide using the formula below. The results may not

exceed the specifications in § 6 of this Standard.

Sample Peak Area

Concentration

Concentration (1)


8.1.4.5 Other accepted instrument techniques such as helium ionization detector may be used.

8.2 Methane, Ethane, Propane, and Silane — This method is for the determination of hydrocarbons (methane,

ethane, and propane) and silane in disilane using a gas chromatograph with a thermal conductivity detector.

8.2.1 Detection Limit — 3 ppm for each impurity.







Detector — 80°C

Injector — 60°C

Oven — 60°C

8.2.3 Calibration Standards — 10–50 ppm methane, 5–10 ppm ethane, 5–10 ppm propane, 0.1%–1% silane, balance

helium.



peak areas. Order of elution is methane, silane, ethane, propane.


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8.2.4.2 Inject the sample to be tested in same manner as the calibration standard. Record the retention times and peak

areas.

8.2.4.3 Repeat ¶ 8.2.4.1.


Calculate the concentrations of methane, silane, ethane, and propane, using the formula below.

Sample Peak Area

Concentration

Concentration (2)


8.3 Hydrogen, Nitrogen, and Argon — This method is for the determination hydrogen, nitrogen, and argon in disilane

using a gas chromatograph with a helium ionization detector.

8.3.1 Detection Limit — 100 ppb for hydrogen and argon, 500 ppb for nitrogen.


8.3.2.1 Columns

Column 1 — Ethylvinylbenzene-divinylbenzene porous polymer absorbent,

2.5 m (8 ft.) by 3.2 mm (1/8 in.) OD ss or equivalent.

Column 2 — 5 Å molecular sieve, 3 m (10 ft.) by 3.2 mm (1/8 in.) OD ss or equivalent.




Detector — 100°C

Injector — 30°C

Oven — 30°C

8.3.3 Calibration Standards — 1–10 ppm nitrogen, 1–10 ppm argon, 10–100 ppm hydrogen, balance helium.

8.3.4 Operating Procedure

8.3.4.1 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.

8.3.4.2 Inject the calibration standard into the column using a gas sampling valve. Backflush at the time determined

in ¶ 8.3.4.1. Record retention times and peak areas. Order of elution is hydrogen, argon, nitrogen.

8.3.4.3 Inject the sample to be tested in same manner as the calibration standard. Backflush at the time determined in

¶ 8.3.4.1. Record the retention times and peak areas.

8.3.4.4 Repeat ¶ 8.3.4.2.


Calculate the concentrations of hydrogen, nitrogen, and argon using the formula below.

Sample Peak Area

Concentration

Concentration (3)


8.4 Disiloxane, Monoethylsilane, Trisilane, and Tetrasilanes — This method is for the determination of disiloxane,

monoethylsilane, trisilane, and tetrasilanes in disilane using a gas chromatograph with a thermal conductivity

detector.

8.4.1 Detection Limits — 5 ppm for disiloxane and 10 ppm for each of the other impurities.



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8.4.2.1 Column — 30% DC 200 on Chromosorb® P, 80/100 mesh, 10 m (33 ft.) by 3.2 mm (1/8 in.) ss or equivalent.




Detector — 120°C

Injector — 60°C

Oven — 60°C for 25 min then 10°C/min to 120°C

8.4.3 Calibration Standard — 100 ppm each of trisilane, i-tetrasilane, and n-tetrasilane, and 10 ppm each disiloxane

and monoethylsilane in helium. If one or several components cannot be obtained, use a 100 ppm monosilane standard

and apply the following correction factors (CFs) using the formula below (see Reference 1):

Trisilane CF = 0.54

i-tetrasilane CF = 0.42

n-tetrasilane CF = 0.41

Correction factors for disiloxane and monoethylsilane are not available. Use the same as disilane CF = 0.69 concentration

of impurity = calculated concentration, using silane standard, × CF.


8.4.4.1 Inject the calibration standard into the column using a gas sampling valve. Record retention times and peak

areas. Order of elution is disiloxane, disilane, monoethylsilane, trisilane, i-tetrasilane, and n-tetrasilane.

8.4.4.2 Inject the sample to be tested in same manner as calibration standard. Record the retention times and peak

areas.

8.4.4.3 Repeat ¶ 8.4.4.1.


Calculate the concentrations of disiloxane, disilane, monoethylsilane, trisilane, i-tetrasilane, and n-tetrasilane, using

the formula below. If necessary, correct the results using the specified CFs in ¶ 8.4.3.

Sample Peak Area

Concentration

Concentration (4)


8.5 Water — This method is for the determination of moisture in disilane using a continuous flow electrolysis

of water in a phosphorus pentoxide (P2O5) cell.

NOTE 4: Direct gases for moisture measurement to the analyzer with stainless steel lines which have been purged.

8.5.1 Flow Requirement — Set the sample flow rate and pressure in accordance with manufacturer’s instructions.


8.5.2.1 Direct samples of three standards, independently verified with a moisture analyzer capable of measuring

1 ppm. After a stable reading is obtained, record the instrument’s response to each standard.

8.5.2.2 Obtain a representative sample of the gas to be analyzed and direct it to the unit as with the standards. After

a stable reading is obtained, record the instrument’s response.

8.5.2.3 Construct calibration curve from the standard data and determine the moisture content in sample gas.

8.5.2.4 Other accepted instrument techniques such as FTIR (Fourier Transform Infrared) may be used.

8.6 Total Chlorides — This method is for the determination of total hydrolyzable chlorides in disilane by titration

of a hydrolyzed sample of disilane (see Figure 2).


8.6.1.1 Equipment


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1. Safety purge regulator with proper fittings.

2. Flow meter capable of measuring 0.25 standard liters per minute (0.5 SCF/hour).

3. One cylinder of nitrogen with regulator.

4. One ice bath.

5. Three magnetic stirring bars.

6. Two 2000 mL heavy-duty sidearm flasks.

7. One #9 one-hole rubber stopper.

8. One #9 two-hole rubber stopper.

9. Two borosilicate glass tubes with fritted cylinders.

10. One gas washing bottle with fritted cylinder, 125 mL cap.

11. One buret, 50 mL capacity with PTFE stopcock.

12. One buret stand.

13. Miscellaneous clamps, support stands, and rubber hose.

14. Two 250 mL Erlenmeyer flasks.

8.6.2 Reagents

1. Potassium hydroxide flakes, technical.

2. Mercuric nitrate crystal.

3. Sodium chloride crystal.

4. Diphenyl carbazone.

5. Bromophenol blue.

6. Nitric acid.

7. Ethanol, denatured.


8.6.3.1 Fill each 2000 mL sidearm flask with about 1700 mL of 15% potassium hydroxide solution (15 g KOH per

each 100 mL water).

8.6.3.2 Fill the gas washing bottle with about 75 mL of deionized water that has been degassed.

8.6.3.3 Assemble apparatus as shown in Diagram A and purge entire system with nitrogen for 30 minutes.

8.6.3.4 Pass 30 liters (approximately one cubic foot) of disilane through the system at a rate of 0.25 liters per minute.

Record the volume of the disilane sample.

8.6.3.5 Stop disilane flow and purge system for 30 minutes.

8.6.3.6 Remove gas washing bottle from system and transfer contents quantitatively and with the aid of three 25 mL

deionized water washings, to a 250 mL Erlenmeyer flask.

8.6.3.7 Add a few drops of indicator solution (5 g diphenyl carbazone plus 0.5 g bromophenol blue dissolved in

750 mL ethanol, plus 250 mL deionized water).

8.6.3.8 Add, in a drop-wise fashion, sufficient 0.2N HNO3 (13 mL conc. HNO3, diluted to 1 L in deionized water) in

order to just turn the solution to yellow from purple.

8.6.3.9 Titrate with a solution of 5 g. mercuric nitrate Hg(NO3)2, (diluted to 1000 mL in deionized water; then

50 mL diluted to 500 mL in deionized water) which has been previously standardized to 5.0 mL of a sodium chloride

solution (approximately 165 ng NaCl, accurately weighed, dissolved in 100 mL deionized water).


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8.6.4 Calibration

8.6.4.1 Run titration blank consisting of 150 mL deionized water.

8.6.4.2 Calculate the concentration of chloride, using the formula below.

mL sample - mL blank

wt. of NaCl (g)

mL standard - mL blank 100.0 mL

60.66% Cl-

1000 mL

0.005 L

1000% NaCl 1 L 35.453 g/mole

0.082 atm L/mole K

294.26K

1 atm volume of gas samples

1 ×106 ppm = ppm Cl - (5)

8.6.5 Final Calculation — Convert the results from ppm to ppm-wt using the formula below.

ppm- wt = ppm mole/mole35.45

62.22 (6)

Figure 1

G.C. Configuration

Analytical Column


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#1 Bleed nitrogen into system at a gentle rate.

#2 Stirrers should turn at a moderate rate.

Figure 2

Chloride Scrubbing Apparatus

NOTICE: SEMI makes no warranties or representations as to the suitability of the standard(s) set forth herein for any

particular application. The determination of the suitability of the standard(s) 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. These standards are subject to change without

notice.

By publication of this standard, Semiconductor Equipment and Materials International (SEMI) takes no position

respecting the validity of any patent rights or copyrights asserted in connection with any item mentioned in this

standard. Users of this standard 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.

Si2H

6

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