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SEMI C31-0301 © SEMI 1978, 2001 METHA NOL 2 mL of the sodium hydroxide solution shou ld be required. 8.4 Alkalinity — A dd 126 mL (10 0 g) o f s ample to 25 mL of water an d mix well . Add 0.05 mL o f me thyl red indicat…
METHANOL SEMI C31-0301 © SEMI 1978, 20011
SEMI C31-0301
SPECIFICATION FOR METHANOL
This specification was technically approved by the Global Process Chemicals Committee and is the direct
responsibility of the North American Process Chemicals Committee. Current edition approved by the North
American Regional Standards Committee on October 17, 1999. Initially available at www.semi.org February
2001; to be published March 2001. This document replaces SEMI C1.10 in its entirety. Originally published
in 1978; previously published June 1999.
1 Purpose
1.1 The purpose of this document is to standardize
requirements for methanol used in the semiconductor
industry and testing procedures to support those
standards. Test methods have been shown to give
statistically valid results. This document also provides
guidelines for grades of methanol for which a need has
been identified. In the case of the guidelines, the test
methods may not have been statistically validated yet.
2 Scope
2.1 The scope of this document is all grades of
methanol used in the semiconductor industry.
2.2 These standards do not purport to address safety
issues, if any, associated with their use. It is the
responsibility of the user of these standards to establish
appropriate safety and health practices and determine
the applicability of regulatory limitations prior to use.
3 Limitations
3.1 None.
4 Referenced Standards
4.1 SEMI Standards
SEMI C1 — Specifications for Reagents
4.2 ASTM Standards
1
ASTM D5127 — Standard Guide for Ultra Pure Water
Used in the Electronics and Semiconductor Industry
NOTE 1: As listed or revised, all documents cited shall be the
latest publications of adopted standards.
5 Terminology
5.1 None.
6 Physical Property (for information only)
Density at 25°C 0.79 g/mL
Boiling Point 64.5°C
1 American Society for Testing and Materials, 100 Barr Harbor
Drive, West Conshohocken, Pennsylvania 19428-2959, USA.
Telephone: 610.832.9585, Fax: 610.832.9555. Website:
www.astm.org
7 Requirements
7.1 The requirements for methanol for Grade 1 are
listed in Table 1.
8 Grade 1 Procedures
NOTE 2: Each laboratory is responsible for verifying the
validity of the method within its own operation.
8.1 Assay — Analyze the sample by gas
chromatography (see SEMI C1, Section 3.1, Guidelines
for Assay by Wide Bore Column Gas
Chromatography). The parameters cited have given
satisfactory results.
Column: 30 meter × 530 micron I.D. fused silica
capillary, coated with 5 micron film of DB-1 or
equivalent (100% methyl silicone which has been
surface bonded and cross linked).
Column Temperature: 40°C isothermal for 5 minutes,
then programmed to 200°C at 10°C/min.
Injector Temperature: 150°C
Detector Temperature: 250°C
Sample Size: 0.2 µL splitless
Carrier Gas: Helium at 3 mL/min
Detector: Thermal Conductivity
Approximate Retention Times
(min):
Methanol 3.0
Ethanol 4.0
Acetone 4.8
8.2 Color — Dilute 2.0 mL of platinum-cobalt stock
solution (APHA No. 500) to 100 mL with water.
Compare this standard (APHA No. 10) with 100 mL of
sample in Nessler tubes. View vertically over a white
background. The sample must be no darker than the
standard.
8.3 Acidity — To 25 mL of water in a glass-stoppered
flask, add 10 mL of sample and 0.1 mL of
phenolphthalein indicator solution. Add 0.01 N sodium
hydroxide until a slight pink color persists after shaking
for one-half minute. Add 42 mL (33 g) of the sample,
mix well, and titrate with 0.01 N sodium hydroxide
until the pink color is reproduced. Not more than 1.0
SEMI C31-0301 © SEMI 1978, 2001 METHANOL2
mL of the sodium hydroxide solution should be
required.
8.4 Alkalinity — Add 126 mL (100 g) of sample to 25
mL of water and mix well. Add 0.05 mL of methyl red
indicator solution. Titrate with 0.01 N hydrochloric acid
until a slight pink color is produced. Not more than 1.0
mL of the hydrochloric acid should be required.
8.5 Residue after Evaporation — Evaporate 253 mL
(200 g) of sample to dryness. Dry at 105°C for 30
minutes, cool in a desiccator, and weigh (see SEMI C1,
Section 3.3, Determination of Residue After
Evaporation).
8.6 Water — Add 50 mL of sample to a dry titration
flask and add Karl Fischer (KF) reagent to a visually or
electrometrically determined endpoint that persists for
30 seconds. Add 50 mL (40 g) of sample, taking care to
protect the sample and contents of the flask from
moisture. Stir vigorously and titrate with Karl Fischer
reagent to the same endpoint.
% Water H
2
O
()
=
mL KF reagent
×
KF factor g H
2
OmL
()
×
100
Weight of sample g
()
8.7 Solubility in Water — Mix 15 mL of sample with
45 mL of water. Allow to stand for 30 minutes. The
solution should be as clear as an equal volume of water.
8.8 Boron — To 127 mL (100 g) of sample, add 0.10
mL of 10% sodium hydroxide solution, and evaporate
to dryness in a nitrogen atmosphere using a covered
chamber such as a Thiers assembly (or equivalent).
Dissolve the residue with 2 mL of water and 0.10 mL of
hydrochloric acid. Transfer to a test tube, cool in an ice
bath, and add 10 mL of sulfuric acid. Then add 10 mL
of carminic acid solution and remove from the ice bath.
Allow to stand for 45 minutes. Prepare a standard
containing 0.001 mg of boron treated exactly as the
sample. Run a complete blank determination on 2 mL
of water. Measure the absorbances of the sample and
standard against the blank at 585 nm using 5.00 cm
cells. The absorbance of the sample solution should be
no greater than that of the standard.
8.9 Chloride — To 63 mL (50 g) of sample, add 10
mL of sodium carbonate reagent solution and evaporate
to dryness on a steam bath in a hood. Dissolve the
residue in 10 mL of water. Add 1 mL of nitric acid and
dilute to 20 mL with water. Add 1 mL of silver nitrate
reagent solution. Any turbidity produced should be no
greater than that produced when 0.01 mg of chloride
ion (Cl) is treated as the sample.
8.10 Phosphate — To 25 mL (20 g) of sample add 10
mL of sodium carbonate reagent solution and evaporate
to dryness on a steam bath in a hood. Dissolve the
residue in 25 mL of 0.5 N sulfuric acid. Add 1 mL of
ammonium molybdate reagent solution and 1 mL of p-
(methylamino)phenol sulfate reagent solution. Allow to
stand at room temperature for 2 hours. Any blue color
produced should be no greater than that produced when
0.01 mg of phosphate ion (PO
4
) is treated as the sample.
8.11 Arsenic and Antimony (as As) — Evaporate 253
mL (200 g) of sample in a 400 mL beaker to a small
volume in a hood. Add 50 mL of water and again
evaporate to a small volume. Repeat the evaporation
with water addition. Do not allow to go to dryness. Add
5 mL of nitric acid and 5 mL of sulfuric acid and
evaporate to dense fumes of sulfur trioxide. Cool,
cautiously add 10 mL of water, and again evaporate to
dense fumes of sulfur trioxide. Cool, and cautiously
wash into a generator flask with water to make a
volume of 35 mL. Proceed as described in the General
Method for Arsenic (and Antimony) under SEMI C1,
Section 3.4.5, starting with the sentence which begins:
“Swirl the flask....” Any red color in the silver
diethyldithiocarbamate solution from the sample should
be no greater than that of the standard containing 0.002
mg of arsenic (As).
8.12 Trace Metal Analysis
8.12.1 Gold (Au) — Analyze by graphite atomic
absorption using the manufacturer's recommended
procedure. This technique has been shown to give
satisfactory results using a 1:4 dilution and Zeeman
background correction. Each laboratory must determine
the appropriate dilution and background correction for
its instrument to meet the specification limit.
8.12.2 The following method has given satisfactory
results in determining trace metal impurities at the
value specified for each of the following trace metals:
aluminum (Al), calcium (Ca), chromium (Cr), copper
(Cu), iron (Fe), lead (Pb), magnesium (Mg), manganese
(Mn), nickel (Ni), potassium (K), sodium (Na), tin (Sn),
titanium (Ti), and zinc (Zn). Alternate methods may be
used as long as appropriate studies demonstrate
recovery between 75 - 125% of a known sample spike
for half of the value of each specified item.
8.12.3 Special Reagents
8.12.3.1 Hydrochloric Acid, Ultra Pure — Use
hydrochloric acid specified for ultra low metal ion
content.
8.12.3.2 2% (v/v) Hydrochloric Acid Solution —
Dilute 20 mL of ultra pure 12 M hydrochloric acid to 1
L using water meeting the criteria for Type E1 in
ASTM D5127.
8.12.4 Sample Preparation
8.12.4.1 In a clean environment, place 250 g of
solvent in a PTFE dish. Slowly evaporate on a hot plate
avoiding loss of sample by effervescence or spattering
METHANOL SEMI C31-0301 © SEMI 1978, 20013
until approximately 1 mL of liquid remains. Take up
liquid and all visible residue (from walls of dish) with 1
mL ultra pure, 12 M hydrochloric acid and continue
heating until approximately 0.5 mL of liquid remains.
No undissolved particulate matter should be observed.
Otherwise repeat the addition of hydrochloric acid until
all particulate matter is dissolved. Transfer
quantitatively to a 50 mL volumetric flask using 2%
(v/v) hydrochloric acid and adjust liquid level to mark.
Prepare a reagent blank using the same reagents and in
the same manner as for the sample concentration.
8.12.5 Analysis
8.12.5.1 Using the prepared sample and reagent blank,
analyze group I elements potassium (K) and sodium
(Na) by atomic absorption spectroscopy and all other
elements by plasma emission spectroscopy. Apply, if
necessary, a reagent blank correction to the final
determined value of the sample.
NOTE 3: Due to the uncertainty of acid concentration in the
liquid residue the final concentration can be estimated to be
approximately 2% (v/v). Standard calibration solutions are to
use this same acid concentration.
9 Grade 2 Procedures
9.1 This section does not apply to this chemical.
10 Grade 3 Procedures
10.1 This section does not apply to this chemical.
11 Grade 4 Procedures
11.1 This section does not apply to this chemical.
12 Grade 5 Procedures
12.1 This section does not apply to this chemical.
13 VLSI Grade Procedures
13.1 This section does not apply to this chemical.
14 Tier A Procedures
14.1 This section does not apply to this chemical.
15 Tier B Procedures
15.1 This section does not apply to this chemical.
16 Tier C Procedures
16.1 This section does not apply to this chemical.
17 Tier D Procedures
17.1 This section does not apply to this chemical.
Table 1 Impurity Limits and Other Requirements for Methanol
Previous SEMI Reference # C1.10-96
Grade 1
(Specification)
Assay (CH
3
OH) 99.9% min
Color (APHA) 10 max
Acidity
0.3 µeq/g max
Alkalinity
0.1 µeq/g max
Residue after Evaporation 5 ppm max
Water (H
2
O) 0.05% max
Solubility in Water To pass test
Boron (B) 0.01 ppm max
Chloride (Cl) 0.2 ppm max
Phosphate (PO
4
) 0.5 ppm max
Aluminum (Al) 0.1 ppm max
Arsenic and Antimony (as As) 0.01 ppm max
Calcium (Ca) 0.1 ppm max
Chromium (Cr) 0.1 ppm max
Copper (Cu) 0.1 ppm max
Gold (Au) 0.1 ppm max
Iron (Fe) 0.1 ppm max
Lead (Pb) 0.1 ppm max
Magnesium (Mg) 0.1 ppm max
Manganese (Mn) 0.1 ppm max