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Background Statement for SEMI Draft Document 5656B

Revision to SEMI C65-0308 with title change to:GUIDE FOR TRIMETHYLSILANE (3MS), 99.995% 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.

Background

SEMI C65 is due for five-year review. This process is required by the Regulations Governing SEMI Standards Committees to ensure that the standard(s) are still valid.

At first, the document was balloted with no technical change, only some formatting changes. Document was rejected on the basis that it does not fit anymore the needs from the industry. The2nd ballot (5656A) included some technical changes in addition to the formatting changes aiming at making the document aligned with current industry requirements. 5656A failed TC Chapter adjudication at SEMICON Europa 2015. This ballot seeks to address the issues raised by reject voters on 5656A.

Notice: Additions are indicated by underline and deletions are indicated by strikethrough.

Ballot Adjudication Information

Task Force Review / Committee Adjudication
Group: / Task Force Review / Committee Adjudication
Date: / PrecursorsTask Force / Joint EU GasesLiquidChemicals TCChapters meeting
Time & Timezone: / October 25, 2016 / October 26, 2016
Location: / 14:00 – 17:00, CET / 10:00 – 13:00, CET
City, Country: / AlpexpoConference Center / AlpexpoConference Center
Leader(s): / Jean-Marie Collard (Solvay)
/ Jean-Marie Collard (Solvay)

Standards Staff: / James Amano, / James Amano,

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.

Check on calendar of event for the latest meeting schedule.

SEMI Draft document 5656B

Revision to SEMI C65-0308 with title change to: GUIDE FOR TRIMETHYLSILANE (3MS), 99.995% QUALITY

Notice: Additions are indicated by underline and deletions are indicated by strikethrough.

1 Purpose

1.1 The purpose of this document is to provide specifications a guide for Trimethylsilane (3MS) used in the semiconductor industry.

2 Scope

2.1 This document covers requirements guides for Trimethylsilane (3MS) used in the semiconductor industry for Plasma Enhanced Chemical Vapor Deposition (PECVD) as low k dielectric and as a SiC etch stop, hard mask and copper diffusion barrier precursor.

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.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.

3 Limitations

3.1 None

3 Description

3.1 Trimethylsilane is a liquefied compressed flammable colorless, non-corrosive gas. Trimethylsilane or 3MS [(CH3)3SiH] is used in the semiconductor industry for Plasma Enhanced Chemical Vapor Deposition (PECVD) as low k dielectric and as a SIC etch stop, hard mask and copper diffusion barrier precursor.

4 Referenced Standards and Documents

4.1 None.

5 Terminology

5.1 Abbreviations and Acronyms

5.1.1 3MS – Trimethylsilane

6 Properties

Table 1Properties of Trimethylsilane (3MS)
Molecular formula / (CH3)3SiH
Molecular weight (g/mol) / 74.2
CAS # / 993-07-7
Metric Units / US Units
Boiling point at 1 atm / 6.7°C / 44.1°F
Density of gas at 25°C (77°F) and 1 atm / 3.1 g/L / 0.193 lb/ft3
Density of liquid at 6.7°C (44.1°F) and 1 atm / 0.64 g/mL / 39.95 lb/ft3
Vapor Pressure at 20°C / 164 kPa / 23.79 psi

5 7 Specifications Suggested Values

7.1 Purity of 99.995% grade for Trimethylsilane (3MS) is given in Table 1. The suggested values for Trimethylsilane (3MS) are given in Table 2.

Table 1Table 2Impurity forSuggested Values for Trimethylsilane (3MS)
Impurities / Maximum Acceptable Level
CarbonMonoxide (CO) / 2 ppmv
CarbonDioxide (CO2) / 2 ppmv
Total Hydrocarbon (THC) / 5 ppmv
Nitrogen (N2) / 2 ppmv
Oxygen (O2) + Argon (Ar) / 2 ppmv
Metals, each element
See Table 23 below. / 5 ppbwtppbv
Water (H20) / 1 ppmv
#1 Ppmv: part per million (vol/vol)
Table 2Table 3List of Metals
Al / Sb / As / Ca / Cr
Co / Cu / Ge / Fe / Pb
Li / Mg / Mn / Ni / K
Na / Sn / Ti / W / Zn

NOTE 1: Standardized test methods are being developed for all parameters at the purity level indicated. Until standardized test methods are published, test methodology shall should be determined by user and producer.

6 Physical Constants

6.1 CAS# 993-07-7

6.2 The physical constants for Trimethylsilane (3MS) are given in Table 3.

Table 3Physical Constants of Trimethylsilane (3MS) (for information only)
Metric Units / US Units
Molecular weight (g/mol) / 74.2 / 74.2
Boiling point at 1 atm / 6.7°C / 44.1°F
Density of gas at 25°C (77°F) and 1 atm / 3.1 g/L / 0.193 lb/ft3
Density of liquid at 6.7°C (44.1°F) and 1 atm / 0.64 g/mL / 39.95 lb/ft3
Vapor Pressure at 20°C / 1.64 Bar / 23.79 psi

7 8 Analytical Procedures

7.1 8.1 Carbon Monoxide and Carbon Dioxide — This procedure is for the determination of carbon monoxide and carbon dioxide using a gas chromatograph with a methanizer and a flame ionization detector.

NOTE 2: An optional temperature ramping during vent will shorten the analysis time.

NOTE 3:NOTE 2: Carrier gases should contain less than 0.1 ppm carbon monoxide and less than 0.1 ppm carbon dioxide.

7.1.1 8.1.1 Detection Limit — 0.1 ppm for each impurity.

7.1.2 8.1.2 InstrumentParameters

7.1.2.1 8.1.2.1 Column:

  • Column 1: Porapak QS 2.5 m (8.2 ft.) by 2.1 mm ID
  • Column 2: Porapak T 2 m (6.6 ft.) by 2.1 mm ID

Column 1: / Porapak QS 2.5 m (8.2 ft.) by 2.1 mm ID
Column 2: / Porapak T 2 m (6.6 ft.) by 2.1 mm ID

7.1.2.2 8.1.2.2 Carrier Flow: 30 mL/min helium.

7.1.2.3 8.1.2.3 Sample Volume: 0.5 mL.

7.1.2.4 8.1.2.4 Support Gases: As specified by the instrument manufacturer.

7.1.2.4.1 8.1.2.4.1 Hydrogen N50: 20–30 mL per min added to the carrier gas between the column outlet and the methanizer inlet.

7.1.2.4.2 8.1.2.4.2 Air: 500 mL/min.

7.1.2.5 8.1.2.5 Temperatures:

  • Detector:350°C
  • Oven:45°C

Detector / 350°C
Oven / 45°C

7.1.3 8.1.3 Calibration Standards — ~5ppm carbon monoxide, ~5ppm carbon dioxide, balance helium.

7.1.4 8.1.4 OperatingProcedure

7.1.4.1 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. Repeat this operation.

7.1.4.2 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. Record the retention times and peak areas.

7.1.4.3 8.1.4.3 Compare the average peak areas of the calibration standard to that of the 3MS sample being tested. Calculate the concentrations of carbon monoxide and carbon dioxide using the formula below. The results may not exceed the specifications guides in Table 2 of this standard.

(1)

(2)

(3)

7.2 8.2 Nitrogen and Oxygen + Argon — This procedure is for the determination nitrogen, oxygen + argon in 3MS using a gas chromatograph with a discharge ionization detector.

7.2.1 8.2.1 DetectionLimit — 0.1ppm

7.2.2 8.2.2 InstrumentParameters

7.2.2.1 8.2.2.1 Columns:

  • Column 1: Porapak QS 3 m (9.8 ft.) by 3.2 mm (1/8 in.) OD ss or equivalent.
  • Column 2: 5A Molecular sieve, 2.5 m (8.2 ft.) by 3.2 mm OD ss or equivalent.

Column 1: / Porapak QS 3 m (9.8 ft.) by 3.2 mm (1/8 in.) OD ss or equivalent.
Column 2: / 5A Molecular sieve, 2.5 m (8.2 ft.) by 3.2 mm OD ss or equivalent.

7.2.2.2 8.2.2.2 Carrier Flow: 30 mL/min. helium.

7.2.2.3 8.2.2.3 Sample Volume: 500l.

7.2.2.4 8.2.2.4 Temperatures:

  • Detector: 100°C
  • Oven: 45°C

Detector / 100°C
Oven / 45°C

7.2.3 8.2.3 Calibration Standards — ~5ppm nitrogen, ~5ppm oxygen, balance helium.

7.2.4 8.2.4 OperatingProcedure

7.2.4.1 8.2.4.1 Inject the calibration standard into the column using a gas sampling valve. Record the retention times and peak areas. Repeat this operation.

7.2.4.2 8.2.4.2 Inject the sample to be tested in same manner as the calibration standard and vent after elution of carbon dioxide is completed. Record the retention times and peak areas.

7.2.4.3 8.2.4.3 Compare the average peak areas of the calibration standard to that of the 3MS sample being tested. Calculate the concentrations of nitrogen and oxygen + argon using the formula below.

(4)

(5)

(6)

7.2.4.4 The results may not exceed the specifications guides in table 2 of this standard.

7.3 8.3 Water — This procedure is for the determination of moisture in 3MS using a vibrating quartz Ametek analyzer equipped with an internal standard permeation device.

NOTE 4:NOTE 3: Direct gases for moisture measurement to the analyzer with stainless steel lines which have been purged.

7.3.1 8.3.1 DetectionLimit — 0.05 ppmv

7.3.2 8.3.2 OperatingProcedure

7.3.2.1 8.3.2.1 Analyzer is permanently flushed sequentially with N2 (<0.5 ppmv) and molecular sieve dried N2 (<30 ppbv). When starting analysis, molecular sieve cartridge (3L) is N2 emptied by decreasing pressure from 3bar to atmospheric pressure. When the analyzer is idle and analysis is not taken place, the detector within the analyzer is continually flushed alternatively with N2 (<0.5ppmv moisture) and molecular sieve dried N2 (<30ppbv moisture). When 3MS analysis commences,the molecular sieve (3L) is first emptied of N2 by decreasing the pressure from 3 bar to atmospheric pressure.

7.3.2.2 8.3.2.2 When atmospheric pressure is obtained, sampling port is switched on 3MS sample. 3MS flow rate is adjusted to 200 sccm.min-1 equivalent N2.Upon reaching atmospheric pressure, the sampling port is switched to allow sampling of 3MS and the 3MS flow rate as measured by the N2 calibrated flow meter is adjusted to 200 sccm .

7.3.2.3 8.3.2.3 Analyzer is then flushed sequentially with 3MS sample and molecular sieve dried 3MS. This enables to obtain a specific response factor on 3MS depending on specific quartz vibration in contact with 3MS. Moisture is then calculated on 3MS sample.

7.3.2.4 8.3.2.4 Wait approximately 30 minutes, until response is stable to read moisture value.After approximately 30 minutes the moisture reading should have stabilized to permit measurement of the moisture level within the 3MS.

7.3.2.5 The results may not exceed the guidesspecifications in table 2 of this standard.

7.4 8.4 Total Hydrocarbon — Standardized test method is being developed for this parameter. Until standardized test method is published, test methodology shall should be determined by user and producer.

7.5 8.5 Metals — Standardized test method is being developed for all parameters at the purity level indicated. Until standardized test method is published, test methodology shall should be determined by user and producer.

NOTICE: SEMI makes no warranties or representations as to the suitability of the standards set forth herein for any particular application. The determination of the suitability of the standard 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 mentioned herein. These standards are subject to change without notice.

The user's attention is called to the possibility that compliance with this standard may require use of copyrighted material or of an invention covered by patent rights. By publication of this standard, 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.

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.

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