Background Statement for SEMI Draft Document 5643
Revision to SEMI C44-0708, SPECIFICATIONS AND GUIDELINES FOR
SULFURIC ACID with title change to: SPECIFICATION AND GUIDE
FOR SULFURIC ACID
Notice: This background statement is not part of the balloted item. It is provided solely to assist the recipient in
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Notice: Additions are indicated by underline and deletions are indicated by strikethrough.
Background
The document will be revised for its five year review and updated per the committee agreed upon changes.
Ballot Adjudication Information
Group:
Date:
Time & Timezone:
Location:
City, State/Country:
Leader(s):
Standards Staff:
Task Force Review
Analytical Methods TF
Wednesday, November 6, 2013
10:00 AM to 12:00 Noon (PST)
SEMI Headquarters
San Jose, CA / USA
Frank Parker / ICL
Frank Flowers / FMC
Michael Tran
408.943.7019
mtran@semi.org
Committee Adjudication
NA Liquid Chemicals Committee
Wednesday, November 6, 2013
1:00 PM to 4:00 PM (PST)
SEMI Headquarters
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Frank Parker / ICL
Frank Flowers / FMC
Michael Tran
408.943.7019
mtran@semi.org
This meeting’s details are subject to change, and additional review sessions may be scheduled if necessary. Contact
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SEMI Draft Document 5643
Revision to SEMI C44-0708, SPECIFICATIONS AND GUIDELINES FOR
SULFURIC ACID with title change to: SPECIFICATION AND GUIDE
FOR SULFURIC ACID
1 Purpose
1.1 The purpose of this document is to standardize requirements for sulfuric acid used in the semiconductor
industry and testing procedures to support those standards. Test methods have been shown to give statistically valid
results. Alternative methods may be used as long as they comply with SEMI C1 requirements for method validation.
This document also provides a guide for grades of sulfuric acid for which a need has been identified. In the case of
these grades , the test methods may not have been statistically validated yet.
2 Scope
2.1 The scope of this document is grades of sulfuric acid used in the semiconductor industry.
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 Limitations
3.1 None.
4 Referenced Standards and Documents
4.1 SEMI Standard and Safety Guidelines
SEMI C1 — Guide for the Analysis of Liquid Chemicals
SEMI C27 — Specification and Guide for Hydrochloric Acid
SEMI C35 — Specification and Guide for Nitric Acid
4.2 ASTM Standard1
ASTM D5127 — Standard Guide for Ultra Pure Water Used in the Electronics and Semiconductor Industry
NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.
5 Terminology
5.1 None.
6 Properties
Table 1 Properties of Sulfuric Acid
Chemical Formula
H2SO4
CAS No.
7664-93-9
Density at 25C
1.83 g/mL
7 Requirements
7.1 The requirements for sulfuric acid for Grades 1 and 2 and suggested values for Tiers B and C are listed in Table
2.
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; http://www.astm.org
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.
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8 Grade 1 Procedures
NOTE 1: Alternative methods may be used as long as they comply with SEMI C1 requirements for method validation
8.1 Assay — Accurately weigh 1 mL of sample in a small glass-stoppered conical flask. Cautiously add 30 mL of
water, cool, add 0.1 mL of methyl orange indicator solution (see SEMI C1), and titrate with standardized 1.0 N
sodium hydroxide to a red to yellow color change.
mL  N of NaOH  4 .904
%Assay 
Weight Mass of sample  g 
8.2 Color — Dilute 2.0 mL of platinum-cobalt stock solution (APHA No. 500; see SEMI C1) 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 shall be no darker than the standard.
8.3 Chloride — Place 40 mL of water in each of two beakers. To one, add carefully 27 mL (50 g) of sample and to
the other, 27 mL (50 g) of chloride-free sulfuric acid and 0.005 mg of chloride ion (Cl). Cool to room temperature
and add 1 mL of nitric acid and 1 mL of silver nitrate reagent solution [SEMI C1]. Mix well; if necessary, make the
volume of each solution identical by adding water. After 10 minutes, measure the turbidity of each solution using a
suitable nephelometer. The turbidity in the sample should shall be no greater than the standard.
NOTE 2: Prepare chloride-free sulfuric acid in a hood by gently fuming sulfuric acid in a crucible or dish for at least 30 minutes.
Cool and transfer to a tightly-capped glass bottle for storage.
8.4 Nitrate — Prepare the following solutions:
Sample Solution A: Cautiously add 27 mL (50 g) of sample
to 1.0 mL of water, dilute to 50 mL
with brucine sulfate reagent solution
and mix.
Control Solution B: Cautiously add 27 mL (50 g) of sample
to 1.0 mL of the standard nitrate
solution containing 0.01 mg of nitrate
ion (NO3) per mL, dilute to 50 mL with
brucine sulfate reagent solution and
mix.
Blank Solution C:
Use 50 mL of brucine sulfate reagent
solution.
8.4.1 Heat the three solutions in a preheated (boiling) water bath for 10 minutes. Cool rapidly in an ice bath to room
temperature. Set a photometer at 410 nm and, using 1 cm cells, adjust the instrument to read zero absorbance with
Blank Solution C in the light path, then determine the absorbance of Sample Solution A. Adjust the instrument to
read zero absorbance with Sample Solution A in the light path and determine the absorbance of Control Solution B.
The absorbance of Sample Solution A should shall be no greater than that Control Solution B.
8.5 Phosphate — Evaporate 11 mL (20 g) of sample to dryness in a platinum dish in a hood. Dissolve the residue in
25 mL of 0.5 N sulfuric acid. Add 1 mL of ammonium molybdate reagent solution (see SEMI C1) and 1 mL
p-(methylamino)phenol sulfate reagent solution (see SEMI C1). Allow to stand at room temperature for 2 hours.
Any blue color produced should shall be no greater than that produced when 0.01 mg of phosphate ion (PO4) (see
SEMI C1) is treated as the sample.
8.6 Arsenic and Antimony (as As) — To 109 mL (200 g) of sample in a beaker, add 5 mL of nitric acid and
evaporate to about 10 mL in a hood. Cool. Cautiously add 10 mL of water, and again evaporate to about 5 mL. Cool,
and cautiously wash into a generator flask with water to make a volume of 35 mL. Proceed as described in General
Method for Arsenic (and Antimony) in SEMI C1, starting with the sentence which begins: “Swirl the flask...” Any
red color in the silver diethyldithiocarbamate solution from the sample should shall be no greater than that of the
standard containing 0.001 mg of arsenic (As) (see SEMI C1).
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
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8.7 Trace Metal Analysis — 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), boron (B), 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). Alternative methods may be used as long as appropriate method
validation as per SEMI C1 can be demonstrated.
8.7.1 Special Reagents
8.7.1.1 Water — The water used for all the dilution, calibration and standards should meet at a minimum the criteria
for Type E1.1 in ASTM D5127 in regard to cation analysis.
8.7.1.2 Indium Internal Standard — Make up the indium internal standard solution to a concentration of
20 µg/mL (ppm) from the appropriate concentrated indium standard solution.
8.7.1.3 Nitric Acid, Ultrapure (SEMI C35, Grade 2)
8.7.1.4 2% Nitric Acid Solution — Dilute 20 mL of ultrapure nitric acid (see § 8.7.1.3) to 1 L using water meeting
the criteria for Type E1.1 in ASTM D5127.
8.7.1.5 Hydrochloric Acid (SEMI C27, Grade 2) Ultrapure Use hydrochloric acid specified for ultra low metal ion
content.
8.7.2 Sample Preparation
8.7.2.1 Boron — In a clean environment, dilute 1.00 g sample with 15.0 g of Type E1.1 water and add 15 µL of the
indium internal standard. Run a reagent blank.
8.7.2.2 Tin — In a clean environment, place 100 g of sulfuric acid in a quartz crucible. Slowly evaporate to dryness
on a hot plate avoiding loss of sample by effervescence or spattering. Cool. Add 2 mL of hydrochloric acid (see §
8.7.1.5) and 10 mL of water. Cover, and digest on the hot plate for 10 minutes. Cool. Transfer quantitatively to a 50
mL volumetric flask using water for rinsing and dilution to volume. Run a reagent blank.
8.7.3 All Other Elements — In a clean environment, place 100 g of sulfuric acid in a quartz crucible. Slowly
evaporate on a hot plate avoiding loss of sample by effervescence or spattering until approximately 2 mL of liquid
remains. Cool. Add carefully, 1 mL of nitric acid (see § 8.7.1.3). While maintaining volume, carefully warm several
minutes to dissolve any residue. Cool. Transfer quantitatively to a 50 mL volumetric flask using 2% nitric acid (see
§ 8.7.1.4) and dilute to volume. Run a reagent blank.
8.7.4 Analysis — Using the prepared solutions and blanks, analyze boron by inductively coupled plasma mass
spectrometry (ICP/MS). Using the acid sample and reagent blank, analyze sodium, calcium, iron and potassium by
flame atomic absorption spectroscopy. Analyze all other elements by plasma emission spectroscopy.
NOTE 3: Analysis of dilute sulfuric acid can produce rapid corrosion of nickel cones commonly used in inductively coupled
plasma mass spectrometry, platinum cones should be considered as alternative when performing this analysis.
9 Grade 2 Procedures
NOTE 4: Alternative methods may be used as long as they comply with SEMI C1 requirements for method validation
9.1 Non-Metal Impurities — See § 8, which contains procedures for the following tests:
 Assay
 Color (APHA)
 Chloride
 Nitrate
 Phosphate
9.2 Trace Metals Analysis
9.2.1 The following method has given satisfactory results in determining metal ion impurities at the values specified
for each of the following metals: aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), boron (B), calcium (Ca),
cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), lithium (Li), magnesium (Mg), manganese (Mn),
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
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nickel (Ni), potassium (K), sodium (Na), tin (Sn), titanium (Ti), vanadium (V), and zinc (Zn). Alternative methods
may be used as long as appropriate method validation as per SEMI C1 can be demonstrated.
9.2.2 Special Reagents
9.2.2.1 Nitric Acid, (SEMI C35, Grade 2) Ultrapure — Use nitric acid specified for low metal ion content.
9.2.2.2 1% Nitric Acid Solution — Dilute 10 mL of ultrapure nitric acid (see § 9.2.2.1) to 1 L using water meeting
the criteria for Type E1.1 in ASTM D5127 with regards to metal content.
9.2.2.3 Water — The water used for all the dilution, calibration and standards should meet at a minimum the criteria
for Type E1.1 in ASTM D5127 in regard to cation analysis.
9.2.2.4 Indium Internal Standard — Make up the indium internal standard solution to a concentration of 20 g/mL
(ppm) from the appropriate concentrated indium standard solution.
9.2.3 Sample Preparation
9.2.3.1 Chromium, Lithium, Manganese, Nickel, Titanium, Vanadium, and Zinc — In a clean environment, place
1.00 g of sample into a clean quartz dish. Slowly evaporate on a hot plate to dryness avoiding loss of sample by
effervescence or spattering. Dissolve the residue with 5 mL of the 1% nitric acid solution (see § 9.2.2.2) by heating
on a hot plate at low temperature for several minutes. Cool to room temperature, dilute to 15 mL with 1% nitric acid
(see § 9.2.2.2), add 15 μL of the indium internal standard, mix well. Run a reagent blank.
9.2.3.2 All Other Elements — In a clean environment, dilute 1.00 g sample with 15.0 g of Type E1.1 water and add
15 μL of the indium internal standard. Run a reagent blank.
9.2.4 Analysis
9.2.4.1 Using the prepared solutions and blanks, analyze sodium, potassium, calcium and iron by graphite furnace
atomic absorption (GFAA) and the remaining elements by inductively coupled plasma mass spectrometry (ICP/MS).
For calibration, the standards are made up with the 1% nitric acid solution (see § 9.2.2.2) and the indium internal
standard such that the final indium concentration is 20 ng/g. For boron and tantalum, the standards for calibration
must be matrix matched with equal amounts of sulfuric acid certified to have both elements below 1 g/mL in the
concentrated acid.
NOTE 5: Analysis of dilute sulfuric acid can produce rapid corrosion of nickel cones commonly used in inductively coupled
plasma mass spectrometry, platinum cones should be considered as alternative when performing this analysis.
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 Tier A Procedures
13.1 This section does not apply to this chemical.
14 Tier B Procedures
14.1 Standardized test methods are being developed for all parameters at the purity levels indicated. Until
standardized test methods are published, test methodology shall be determined by user and producer. The Liquid
Chemicals Committee considers a test method to be valid only if method validation according to SEMI C1 can be
demonstrated.
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
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15 Tier C Procedures
15.1 Standardized test methods are being developed for all parameters at the purity levels indicated. The Liquid
Chemicals Committee considers a test method to be valid only if method validation according to SEMI C1 can be
demonstrated.
16 Tier D Procedures
16.1 This section does not apply to this chemical.
Table 2 Impurity Limits, Suggested Values and Other Requirements for Sulfuric Acid
Previous SEMI Reference #
Assay (H2SO4)
SEMI C1.16-96
SEMI C7.8-94
SEMI C8.8-92
Grade 1
Grade 2
Tier B
Tier C
(Specification)
(Specification)
(Guide)
(Guide)
95.0%–97.0%
95.0%–97.0 %
95.0%–97.0%
95.0%–97.0%
Color (APHA)
10 max.
10 max.
10 max.
10 max.
Chloride (Cl)
0.1 ppm max.
100 ppb max.
50 ppb max.
50 ppb max.
Nitrate (NO3)
0.2 ppm max.
200 ppb max.
100 ppb max.
100 ppb max.
Phosphate (PO4)
0.5 ppm max.
500 ppb max.
100 ppb max.
100 ppb max.
Aluminum (Al)
0.2 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Antimony (Sb)
--
5 ppb max.
1 ppb max.
100 ppt max.
Arsenic (As)
--
10 ppb max.
1 ppb max.
100 ppt max.
Arsenic and Antimony (as As)
0.005 ppm max.
--
--
--
Barium (Ba)
--
10 ppb max.
1 ppb max.
100 ppt max.
Boron (B)
0.02 ppm max.
20 ppb max.
1 ppb max.
100 ppt max.
Cadmium (Cd)
--
10 ppb max.
1 ppb max.
100 ppt max.
Calcium (Ca)
0.3 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Chromium (Cr)
0.2 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Copper (Cu)
0.1 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Iron (Fe)
0.2 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Lead (Pb)
0.3 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Lithium (Li)
--
10 ppb max.
1 ppb max.
100 ppt max.
Magnesium (Mg)
0.3 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Manganese (Mn)
0.2 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Nickel (Ni)
0.1 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Potassium (K)
0.3 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Sodium (Na)
0.3 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Tin (Sn)
0.2 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Titanium (Ti)
0.3 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Vanadium (V)
--
10 ppb max.
1 ppb max.
100 ppt max.
Zinc (Zn)
0.2 ppm max.
10 ppb max.
1 ppb max.
100 ppt max.
Particles in bottles: (size, #/mL)
(See
#1)
(See
#1)
(See
#1)
(See #1)
#1 Due to the limitations of current particle counters, particle size and number are to be agreed upon between supplier and
user. See SEMI C1 in the section of Calibration and Measurement Method for Particles in Liquids.
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NOTICE: Semiconductor Equipment and Materials International (SEMI) makes no warranties or representations as
to the suitability of the Standards and Safety Guidelines set forth herein for any particular application. The
determination of the suitability of the Standard or Safety Guideline 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. Standards and Safety Guidelines are subject to change
without notice.
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