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1、 SEMI C1-0705 SEMI 1978, 2005 1 SEMI C1-0705 GUIDE FOR THE ANALYSIS OF LIQUID CHEMICALS This guide was technically approved by the global Liquid Chemicals Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on April 7, 2005. It was available at www.semi
2、.org in June 2005 and on CD-ROM in July 2005. Originally published in 1978; previously published July 2004. 1 Purpose 1.1 Liquid Chemicals are used extensively during the production of semiconductor devices; their purity has been shown to affect the device yield during the manufacturing processes. 1
3、.2 Since there is a wide range of semiconductor devices being produced, different levels of purity have been established as standards and guidelines for each liquid chemical. 1.3 This guide describes the various analytical procedures for standards verification procedures required to meet a specific
4、liquid chemical specification. 2 Scope 2.1 All liquid chemical standards consist of guidelines, specifications and validated analytical procedures. Suitable analytical procedures are defined in each standard for each grade of liquid chemical such that their sensitivity meets the requirements of each
5、 of the respective grades of liquid chemicals. 2.2 This guide provides an overview of each of the methods used for liquid chemical certification. Each grade of liquid chemicals (15) that have been validated analytically using the appropriate procedures described in this guide can be described as “me
6、eting SEMI specifications.” 2.3 Analytical Procedures The procedures used to establish a liquid chemical specification can be found in 7. The Analytical Procedures are listed in Table 1. 2.4 Safety Because of the continuing evolution of safety precautions, it is impossible for this publication to pr
7、ovide definite statements related to the safe handling of individual liquid chemicals. The user is referred to product labels, product data sheets, government regulations, and other relevant literature. NOTICE: This guide does not purport to address safety issues, if any, associated with its use. It
8、 is the responsibility of the users of this guide to establish appropriate safety and health practices and determine the applicability of regulatory or other limitations prior to use. Table 1 Analytical Procedures 7.1 Acidity and Alkalinity 7.2 Assay by Wide Bore Column Gas Chromatography 7.3 Color
9、7.4 Residue after Evaporation 7.5 Residue after Ignition 7.6 Trace Arsenic (and Antimony) Determination 7.7 Use of a pH Meter 7.8 Ion Chromatography 7.9 Atomic Absorption Spectrometry (AAS) 7.10 Flame Emission Spectrometry 7.11 Graphite Furnace Atomic Absorption Spectrometry (GFAAS) 7.12 Inductively
10、 Coupled Plasma Optical Emission Spectrometry (ICP-OES) 7.13 Inductively Coupled Plasma Mass Spectrometry (ICP-MS) 7.14 Calibration and Measurement Method for Particles in Liquids SEMI C1-0705 SEMI 1978, 2005 2 3 Referenced Standards and Documents 3.1 ASTM Standards1 ASTM D5127 Standard Guide for Ul
11、tra 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
12、abbreviations and signs used shall be restricted to those used in publications of the American Chemical Society (ACS)2. 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.
13、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 s
14、pecified. (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 materia
15、l 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
16、Chemistry (IUPAC)3. 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,
17、 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,
18、 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 lar
19、ge 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.
20、010 mg/mL to 10. ng/mL.4 4.8 Density The density of a liquid shall be determined for the compound in air at 25C 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
21、 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 Har
22、bor 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:
23、/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 C
24、1-0705 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 on
25、e 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 o
26、f 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 in
27、tervening “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
28、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 purpo
29、ses; 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 25C. 4.14 Reagent Chemicals Unless otherwise stated, reagents to be used in tests s
30、hall conform to the minimum standards of quality set forth in the current edition of Reagent Chemicals, published by the American Chemical Society5. 4.15 Residue after Evaporation A “residue after evaporation” test may be used in the assessment of liquid chemicals. (See Determination of Residue afte
31、r 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
32、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
33、.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 retai
34、ned 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 co
35、ntainers, 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
36、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 liq
37、uid 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 requir
38、ed 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 -,-,- SEMI C1-0705 SEMI 1978, 2005 4 4.19
39、.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
40、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
41、 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 procedure
42、s 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
43、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
44、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 Wat
45、er 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 specificati
46、ons 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 ca
47、pitalized. 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
48、 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 operat
49、ions. 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 co