Background Statement for SEMI Draft Document 5134 Revision to SEMI C , Specifications for Hydrofluoric Acid

Transcription

1 Background Statement for SEMI Draft Document 5134 Revision to SEMI C , Specifications for Hydrofluoric Acid 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 C28 is due for 5-year review. This process is required for all SEMI Standards and Safety Guidelines. A preliminary review of the document revealed that some minor changes were needed. This ballot makes those changes. Review and Adjudication Information Task Force Review Committee Adjudication Group: Analytical Methods TF NA Liquid Chemicals Committee Date: Tuesday 12 April 2011 Tuesday 12 April 2011 Time & Timezone: TBD, CDT TBD, CDT Location: ICL Performance Products Tech Center ICL Performance Products Tech Center City, State/Country: 373 Marshall Ave Webster Groves, MO Marshall Ave Webster Groves, MO Leader(s): Frank Flowers (FMC) Frank Parker (ICL) Frank Flowers (FMC) Frank Parker (ICL) Standards Staff: Ian McLeod (SEMI NA) imcleod@semi.org Ian McLeod (SEMI NA) imcleod@semi.org 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. i

2 SEMI Draft Document 5134 Revision to SEMI C , Specifications for Hydrofluoric Acid NOTICE: Additions are marked by underline, deletions are marked by strikethrough. 1 Purpose 1.1 The purpose of this document is to standardize requirements for hydrofluoric acid used in the semiconductor industry and testing procedures to support those standards. Test methods have been shown to give statistically valid results. 2 Scope 2.1 The scope of this document is all grades of hydrofluoric 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 Standards SEMI C1 Guide for the Analysis of Liquid Chemicals 4.2 ASTM Standards 1 ASTM D5127 Standard Guide for Ultra Pure Water Used in the Electronics and Semiconductor Industry 4.3 Other Documents Dionex Technical Note 45 Determination of Trace Anions in Concentrated Hydrofluoric Acid NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions. 5 Terminology 5.1 None. 6 Physical Property (for information only) Density at 25 C 1.15 g/ml 7 Requirements 7.1 The requirements for hydrofluoric acid for Grades 1, 2, 3 and 4 are listed in Table 1. 8 Grade 1 Procedures NOTE 1: Each laboratory is responsible for verifying the validity of the method within its own operation. 8.1 Assay Accurately weigh ml of sample in polyethylene weighing bottle, sample, stopper immediately, and reweigh. To 50 ml of water in a plastic vessel, add the sample (loosen the stopper of the polyethylene bottle, and add both the container and the stopper with the sample). Add 0.1 ml of phenolphthalein indicator solution, and titrate with standardized 1 N sodium hydroxide to a slight, pink color. %Assay ml N of NaOH Weight of sample g Alternately, potentiometric end point detection can be used. 1 American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, Pennsylvania , USA. Telephone: , Fax: Website: Page 1

3 8.2 Chloride Add 1.7 ml (2.0 g) of sample to 45 ml of water. Filter, if necessary, through a chloride-free filter. Add 1 ml of nitric acid and 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. 8.3 Nitrate Weigh 3.3 g of sample in a white plastic 50 ml beaker and dilute with 4.5 ml of water. To another 50 ml plastic beaker, add 6.5 ml of water and 1 ml of standard nitrate solution containing 0.01 mg of nitrate (NO 3 ) per ml. To each solution, add 2.5 ml of brucine sulfate reagent solution and cautiously add with stirring 20 ml of sulfuric acid. Allow to stand for 10 minutes. The yellow color in the sample solution should be no greater than that in the standard solution. 8.4 Phosphate Evaporate 9 ml (10 g) of sample to dryness in a platinum or other suitable dish 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 for 2 hours at room temperature. Any blue color should be no greater than that produced when 0.01 mg of phosphate ion (PO 4 ) is treated like the sample. 8.5 Sulfate and Sulfite (as SO 4 ) To 18 ml (20 g) of sample in a platinum or other suitable evaporating dish, add about 10 mg of sodium carbonate and 1 ml of 30 hydrogen peroxide. Evaporate to dryness on a steam bath in a hood, wash down the sides of the dish with a small volume of water, and add 3 ml of perchloric acid. Evaporate to about 1 ml, dilute with about 15 ml of water, and add 0.01 ml of phenolphthalein indicator solution. Neutralize with ammonium hydroxide, dilute with water to 20 ml, and add 2 ml of dilute hydrochloric acid (1 + 19) and 2 ml of barium chloride reagent solution. Any turbidity should not exceed that produced by 0.1 mg of sulfate ion (SO 4 ) in an equal volume of solution containing the quantities of reagents used in the test. Compare 10 minutes after adding the barium chloride to the sample and standard solutions. NOTE 2: For anion determination, alternate method based upon ion chromatography may be used, see 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), antimony (Sb), arsenic (As), barium (Ba), boron (B), cadmium, (Cd), calcium (Ca), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), lithium (Li), magnesium (Mg), manganese (Mn), nickel (Ni), potassium (K), sodium (Na), tin (Sn), titanium (Ti), vanadium (V) and zinc (Zn). An alternate method is described in 9.2. Any other alternate methods may be used as long as method validation according to SEMI C1 can be demonstrated Special Reagents Nitric Acid, Ultra Pure Use nitric acid specified for ultra low metal ion content % Nitric Acid Solution Dilute 20 ml of ultra pure nitric acid to 1 L using water meeting the criteria for Type E1.1 in ASTM D Sample Preparation In a clean environment, place 250 g of sample in a PTFE evaporating dish. Slowly evaporate on a hot plate, avoiding loss of sample by effervescence or spattering until approximately 2 ml of liquid remains. NOTE 3: Evaporation typically requires 2 1/2 to 4 hours. Cool. Add 1 ml of ultra pure, 70% nitric acid. While maintaining volume, carefully warm several minutes to dissolve any residue. Cool. Transfer quantitatively to a 50 ml volumetric flask using 2% nitric acid for rinsing and dilution to volume. Run a reagent blank Analysis Using the acid sample and reagent blank, analyze all specified elements by plasma emission spectroscopy or preferably by ICP-MS. 9 Grade 2 Procedures NOTE 4: Each laboratory is responsible for verifying the validity of the method within its own operation. 9.1 Non-Metal Impurities See 8, which contains procedures for the following tests: Assay, Chloride, Nitrate, Phosphate, and Page 2

4 Sulfate and Sulfite (as SO 4 ). 9.2 Trace Metals 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), antimony (Sb), arsenic (As), barium (Ba), boron (B), cadmium (Cd), calcium (Ca), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), lithium (Li), magnesium (Mg), manganese (Mn), nickel (Ni), potassium (K), sodium (Na), tin (Sn), titanium (Ti), vanadium (V), and zinc (Zn). Alternate method can be used as long as method validation according to SEMI C1 can be demonstrated Special Reagents Hydrofluoric Acid, Ultra Pure Use hydrofluoric acid specified for low metal ion content % Hydrofluoric Acid Solution Dilute 20 g of ultrapure hydrofluoric acid to 200 g using water meeting the criteria for Type E1.1 in ASTM D 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 Indium Internal Standard Make up a internal standard solution to a concentration of 20 g/ml (ppm) from the appropriate concentrated indium standard solution Sample Preparation In a clean environment, place 2.00 g of sample into a tared FEP bottle (30 ml), dilute with Type E1.1 water to a final weight of 20.0 g. Add 20 L of the indium internal standard solution. Run a reagent blank Analysis Using the prepared solutions and blanks, analyze all the specified elements by inductively coupled plasma mass spectrometry (ICP/MS). For calibration, the standards are made up with the 4.9% hydrofluoric acid solution and the indium internal standard such that the final concentration is 20 ng/g of indium. NOTE 5: Analysis of dilute hydrofluoric acid requires the use of special hydrofluoric acid resistant sample introduction systems for inductively coupled plasma mass spectrometry. These systems are available from most instrument suppliers. NOTE 6: Analysis of dilute hydrofluoric 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 Assay See Chloride, Nitrate, Sulfate, Phosphate The above mentioned anions can be determined by ion chromatography using a two dimensional approach. For a detailed procedure, see for example Dionex Technical Note 45. Better results are obtained when using an IonPac ICE-AS1 column instead of the IonPac ICE-AS6 recommended in the TN45. Calibration is preferably done by the method of standard addition. Alternate method can be used as long as method validation according to SEMI C1 can be demonstrated 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), antimony (Sb), arsenic (As), barium (Ba), boron (B), cadmium (Cd), calcium (Ca), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), lithium (Li), magnesium (Mg), manganese (Mn), nickel (Ni), potassium (K), sodium (Na), tin (Sn), titanium (Ti), vanadium (V), and zinc (Zn). Alternate method can be used as long as method validation according to SEMI C1 can be demonstrated Special Reagents Nitric Acid, Ultra Pure Use nitric acid specified for ultra low metal ion content % Nitric Acid Solution In a clean environment, place 15 g of Ultra Pure Nitric Acid into a tared clean 500 ml FEP bottle. Dilute to a final weight of 500 g using ultrapure water Water The water used for all the dilutions, calibrations and standards should meet at a minimum the criteria for Type E1.2 in ASTM D5127 in regard to cation analysis Sample Preparation In a clean environment, place 20 g of sample into a tared clean 120 ml FEP bottle. Dilute to a final weight of 100 g with the 3 % Nitric Acid Solution Page 3

5 Analysis Using the prepared solutions, analyze all the specified elements by inductively coupled plasma mass spectrometry (ICP-MS). For calibration, blank and standards are made up with the 3 % Nitric Acid Solution NOTE 7: Analysis of dilute hydrofluoric acid requires the use of special hydrofluoric acid resistant sample introduction systems for inductively coupled plasma mass spectrometry. These systems are available from most instrument suppliers. NOTE 8: Analysis of dilute hydrofluoric 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. NOTE 9: The analytical methodology described in 10.3 has been validated using a Reaction / Collision cell type ICP-MS. Other instrument type can be used as long as method validation according to SEMI C1 can be demonstrated. 11 Grade 4 Procedures 11.1 Assay See Chloride, Nitrate, Sulfate, Phosphate See Trace Metal Analysis See 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 This section does not apply to this chemical. 15 Tier C Procedures 15.1 This section does not apply to this chemical. 16 Tier D Procedures 16.1 This section does not apply to this chemical. Table 1 Impurity Limits and Other Requirements for Hydrofluoric Acid Previous SEMI Reference # C C C Grade 1 Grade 2 Grade 3 Grade 4 (Specification) (Specification) (Specification) (Specification) Assay (HF) (see NOTE 10) Appearance Clear and colorless Clear and colorless Clear and colorless Clear and colorless Chloride (Cl) 5 ppm max 5000 ppb max 200 ppb max 100 ppb max Nitrate (NO 3 ) 3 ppm max 3000 ppb max 100 ppb max 100 ppb max Phosphate (PO 4 ) 1 ppm max 1000 ppb max 100 ppb max 100 ppb max Sulfate (SO 4 ) ppb max 100 ppb max Sulfate and Sulfite (as SO 4 ) 5 ppm max 5000 ppb max -- Aluminum (Al) 0.05 ppm max 10. ppb max 1 ppb max 100 ppt max Antimony (Sb) 0.03 ppm max 15 ppb max 1 ppb max 100 ppt max Arsenic (As) 0.03 ppm max 15 ppb max 1 ppb max 100 ppt max Barium (Ba) ppb max 1 ppb max 100 ppt max Page 4

6 Previous SEMI Reference # C C C Grade 1 Grade 2 Grade 3 Grade 4 (Specification) (Specification) (Specification) (Specification) Boron (B) 0.05 ppm max 10. ppb max 1 ppb max 100 ppt max Cadmium (Cd) 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) 0.01 ppm max 10. ppb max 1 ppb max 100 ppt max Copper (Cu) 0.05 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) 0.1 ppm max 10. ppb max 1 ppb max 100 ppt max Lithium (Li) ppb max 1 ppb max 100 ppt max Magnesium (Mg) 0.2 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) 0.3 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) ppb max 1 ppb max 100 ppt max Zinc (Zn) 0.3 ppm max 10. ppb max 1 ppb max 100 ppt max Particles in bottles (size, #/ml) 1.0 m, 25 max 0.5 m, 25 max 0.5 m, 5 max 0.2 m, TBD TBD Due to the limitations of current particle counters, particle size and number are to be agreed upon between supplier and user. See SEMI C1, Calibration and Measurement Method for Particles in Liquids NOTE 10: For reason related mainly to transportation regulations, the typical assay range is different between US and Europe. NOTICE: SEMI makes no warranties or representations as to the suitability of the standard(s) set forth herein for any particular application. The determination of the suitability of the standard(s) 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. These standards are subject to change without notice. By publication of this standard, Semiconductor Equipment and Materials International (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. Page 5