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SEMI C1-0705 © SEMI 1978, 2005 3 4.10 Dryin g or Ignit ing to Constant Weight — A statement “dried to a constant weight” or “ignited to a constant weight” shall imply that two separate weighings differ by no more than ± …

SEMI C1-0705 © SEMI 1978, 2005 2

3 Referenced Standards and Documents

3.1 ASTM Standards

ASTM D5127 — Standard Guide for Ultra Pure Water Used in the Electronics and Semiconductor Industry

ASTM E203 — Standard Test Method for Water Using Volumetric Karl Fischer Titration

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

4 Requirements

4.1 Abbreviations and Signs — In this guide abbreviations and signs used shall be restricted to those used in

publications of the American Chemical Society (ACS)

4.2 Accuracy and Tolerances in Measurements — In a test procedure, unless otherwise specified, the accuracy

required in the amount of sample taken shall be understood to be within 2.0% of the stated amount, whether a

weight or a volume. Where a dilution is performed to a stated volume or a stated volume of a solution is taken, that

volume shall be within 2.0% of the stated amount.

4.3 Acidity and Alkalinity — A test for acidity or alkalinity, or both, of liquid chemicals may be specified. (See

Acidity and Alkalinity in ¶7.1.)

4.4 Analytical Blank — Where a “blank” is specified to be run, unless otherwise stated, it shall be performed with

the same quantities of the same reagents and in a manner identical to that followed with the sample portion under

test, but with the material itself omitted.

4.5 Apparatus — Apparatus, unless otherwise qualified, shall be that commonly employed in the conduct of the

relevant test.

4.6 Atomic and Formula Weights — Atomic weights (i.e. atomic masses) used shall be those of the latest

publication of The International Union of Pure and Applied Chemistry (IUPAC)

. Formula weights shall be

calculated from a given empirical (molecular) formula by addition of the stated multiples of the atomic weights.

Unless otherwise stated, formula weights shall be rounded to 2 significant figures to the right of the decimal point

(see Rounding of Numbers, ¶4.17).

4.7 Comparison of Analytical Results with Specification Limits — In the comparison of an analytical result for a test

with the numerical limit associated with the specification, the result shall be rounded to the number of significant

figures indicated for that limit. (See Rounding of Numbers, ¶4.17.) Consequently, a specification stated at 96%

minimum will be met by a result as small as 95.5%, and that stated as 96.0% minimum will be met by a result as

small as 95.95%. A specification of 0.1% maximum will be met by a result as large as 0.149%, and that of 0.10%

maximum by a result as large as 0.105%. In those specifications given with no digit following the decimal point,

such as 10 ng/mL maximum, a test result as large as 10.5 ng/mL will meet the specification. This use of a decimal

point is made to clarify the difference between converting 0.01 mg/mL to 10 ng/mL and converting 0.010 mg/mL to

10. ng/mL.

4.8 Density — The density of a liquid shall be determined for the compound in air at 25°C and be expressed in

grams/milliliter (g/mL). Where the specific gravity, with respect to water, is determined, it shall be expressed as

density by the use of tabular values for the density of water at the relevant temperature(s).

4.9 Desiccator — A desiccator shall imply a tightly closed container charged with a suitable desiccant (commonly

calcium chloride or sulfate) that allows an atmosphere of low humidity to be maintained.

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

2 http://www.cas.org/ONLINE/standards.html, American Chemical Society, 1155 Sixteenth Street, NW, Washington DC, 20036, Phone: 202-

872-4600, Fax: 202-872-4615, Website: http://www.chemistry.org

3 The International Union of Pure and Applied Chemistry, PO Box 13757, Research Triangle Park, NC 27709-3757, USA, Website:

http://www.iupac.org

4 H.A. Flachka, A.J. Barnard Jr., P.E. Sturrock. Quantitative Analytical Chemistry, Willard Grant Press, 2nd ed., 1980, p 4.

SEMI C1-0705 © SEMI 1978, 2005 3

4.10 Drying or Igniting to Constant Weight — A statement “dried to a constant weight” or “ignited to a constant

weight” shall imply that two separate weighings differ by no more than ± 0.4 mg (unless otherwise specified), where

the second weighing follows a second drying (for one hour (unless otherwise stated) or ignition for 15 minutes

(unless otherwise stated), respectively.

4.11 Expression of Content and Concentration — Unless otherwise stated, a specification limit and experimental

results related to it shall be expressed in units of weight by weight. The concentration of a solution of a test reagent

shall be expressed either in molarity or normality or as percent weight by volume. A redox normality value shall

always be followed, parenthetically, by the relevant molarity. In the approximate dilution of reagents, a

parenthetical expression of two numbers with an intervening “plus” sign shall imply that the relative volume of the

stated reagent given by the first number shall be admixed with the relative volume of water given by the second

number. Thus, “dilute” sulfuric acid (1 + 3) directs that one volume of reagent grade sulfuric acid be added to 3

volumes of water and the mixture stirred to form a uniform solution.

4.12 Filtration — A statement to “filter,” unless qualified, shall imply filtration through suitable filter paper until

the filtrate is clear.

4.13 Physical Properties — Physical properties shall not usually be employed for specification purposes; for

information, however, representative values for a particular liquid chemical, as supplied, may be included in the

standard for that liquid chemical. Where relevant, physical properties shall be specified for 25°C.

4.14 Reagent Chemicals — Unless otherwise stated, reagents to be used in tests shall conform to the minimum

standards of quality set forth in the current edition of Reagent Chemicals, published by the American Chemical

Society

4.15 Residue after Evaporation — A “residue after evaporation” test may be used in the assessment of liquid

chemicals. (See Determination of Residue after Evaporation, ¶7.4.)

4.16 Residue after Ignition — A “residue after ignition” test serves to assess the amount of nonvolatile inorganic

matter present in a sample. (See Determination of Residue after Ignition, ¶7.5.)

4.17 Rounding of Numbers — The following rules for “rounding” of measured or calculated values shall be

employed:

4.17.1 When the figure next beyond the last place to be retained is less than 5, leave unchanged the figure in the last

place retained.

4.17.2 When the figure next beyond the last place to be retained is greater than 5, increase by 1 the figure in the last

place retained.

4.17.3 When the figure next beyond the last place to be retained is 5 and there are no figures beyond this 5 or only

zeroes, (a) increase by 1 the figure in the last place retained if it is odd, or leave the figure unchanged if it is even.

4.17.4 When the figure next beyond the last place to be retained is 5 and there are figures other than zeroes beyond

this 5 increase by 1 the figure in the last place retained.

4.17.5 Obtain the rounded value in one step by direct rounding and not in two or more steps of successive

roundings.

4.18 Samples and Sampling — For liquid chemicals provided in small containers, one (or more) should be freshly

opened for testing, thereby reducing possibilities for contamination or change in composition (for example, by

moisture pickup). Where the liquid chemical is provided in larger bulk quantities, one or more drums or other

containers shall be sampled to avoid cross contamination, and the combined sample shall be placed in a labeled,

well-cleaned container that shall be tightly closed and transferred expeditiously to the testing laboratory.

4.19 Specifications and Specification Limits — The specifications provided by this guide are intended to serve for

liquid chemicals to be used in the manufacture and processing of semiconductors and advanced electronic devices

and circuits. The specifications and the associated test procedures are based on the experience of suppliers and users

and also on published studies relating to liquid chemicals of the required quality. The function of the specifications

is to establish minimum standards of quality.

5 Available from American Chemical Society, 1155 Sixteenth Street, NW, Washington DC, 20036, Phone: 202-872-4600, Fax: 202-872-4615,

Website: http://www.chemistry.org

4.19.1 Where feasible, a specification of content shall be expressed as a numerical limit in units of weight by

weight. For a specification that cannot be assigned such a limit, the expression “To pass test” shall be used.

4.19.2 For a major component, the value (assay, purity, etc.) shall be expressed as a minimum permissible limit or

range. For an impurity, the value shall be expressed as a maximum permissible limit.

4.19.3 A liquid chemical conforming to the specification will commonly contain either more of the major

component than the minimum permissible limit or be within the specified range for the liquid chemicals and contain

less of each impurity (or impurities) than the maximum permissible limit. In neither case shall the liquid chemicals

be considered as of higher quality than that defined by the specification.

4.19.4 It is manifestly impossible in the specifications and procedures for a liquid chemical to consider every

impurity or contaminant that might be present. For certain applications, it is recognized that more stringent or

additional specifications and procedures might be required. The intent of these specifications and the associated

procedures is, on one hand, to assure that a liquid chemical is suitable for the common uses to which it may be put in

the manufacture and processing of semiconductor devices and, on the other hand, to be consistent with

contemporary manufacturing processes for that liquid chemical.

4.20 Specification Parameters — The statement of specification parameters for a particular liquid chemical shall

be, as far as practical.

4.20.1 Assay or other test assessing the component(s) of interest

4.20.2 Appearance or color

4.20.3 Acidity or alkalinity, or both, or pH range of solution

4.20.4 Residue after evaporation or ignition

4.20.5 Water content

4.20.6 Diverse general tests, arranged alphabetically

4.20.7 Tests for stated anions and ammonium shall be arranged alphabetically (ammonium, chloride, nitrate,

phosphate, sulfate)

4.20.8 Tests for specific trace metals, arranged alphabetically by name. The 21 metals for grade specifications

higher than Grade 2 are Aluminum, Antimony, Arsenic, Barium, Boron, Cadmium, Calcium, Chromium, Copper,

Iron, Lead, Lithium, Magnesium, Manganese, Nickel, Potassium, Sodium, Tin, Titanium, Vanadium, and Zinc.

4.20.9 All major words in a specification parameter shall have their initial letters capitalized.

4.20.10 Following the statement of a specification parameter, where relevant, the species on which the calculation

of the result is based shall be expressed parenthetically as the atomic symbol or empirical formula.

4.21 Tared Containers — Where the use of a tared container is specified, it shall be carried through operations

identical to those used in the test procedures, including drying or ignition, or both, cooling in a desiccator, and

weighing. When a new container is placed in service, special measures may be required to assure that it is brought

to constant weight by the operations.

4.22 Temperature — Temperature values shall be expressed in degrees Celsius (°C).

4.23 Water — References to water in the testing procedures are understood to mean water that is of the appropriate

grade for the intended purpose. Depending on the grade of liquid chemical being tested, water meeting the

requirements for Types E-1, E-1.1, and E-1.2 water in ASTM Standard Guide D5127 may be used. In tests for

nitrogen compounds, water should be “ammonia-free” or “nitrogen-free.” For some tests, freshly boiled water must

be used in order to ensure freedom from material absorbed from the air such as ammonia, carbon dioxide, or

oxygen.