AIR PERMITTING WAFER FABS. MIKE SHERER SHERER CONSULTING SERVICES, INC

Transcription

1 AIR PERMITTING WAFER FABS MIKE SHERER SHERER CONSULTING SERVICES, INC

2 Chiller(s) Temp. Control Hum. Controls CDA Vac. Wafers In Other - In Elec. Power ESD Control Vib. Control Domestic H 2 O Recirc. Air MU Air R/O Simplified Fab Schematic Fab DIW Spec.Gases Bulk Gases Solvent Drain Solvent Waste Tank Waste Abatements Acid.Exh. VOC Exh. NH 3.Exh. Gen/heat Exh. Tool Set Control And Supervisory Systems Sanitary Drain Corrosive Drain Corrosive WW Treatment Fluoride Drain Acids/Bases Sanitary Sewer Domestic H 2 O Chem Stg Solvents Fluoride WW Treatment Washdown Solv Stg Wafers Out Domestic H 2 O Washdown Waste

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4 Air Permitting Strategies The site-wide bubble permit is best for semiconductor fabs as it allows for installing, removing and moving equipment at the site without filing for permit modifications, generally if site-wide emissions are not exceeded or new applicable regulations are not triggered. Some air quality agencies require equipmentspecific air permitting.

5 Air Permitting Strategies (Continued) Determine potential-to-emit emissions for site assuming maximum chemical and gas usages and Facilities equipment information. Emissions from emergency generators & fire pumps, boilers, volatile organic compound (VOC) control equipment, and point-of-use abatement devices should be included.

6 Air Permitting Strategies (Continued) Determine equipment and emissions that do not need to be permitted (e.g., insignificant and trivial activities). These will reduce recordkeeping, etc. Understand local and federal regulations that affect site (i.e., do not file a permit that violates a regulation or misses a requirement).

7 Possible Air Permit Application Application form. Word document providing all emission factors used to calculate emissions, the basis for these emission factors and all abatement removal efficiencies with corresponding support information. Excel spreadsheets providing usages, emissions calculations and summing up site-wide emissions for each pollutant. Combine pollutants into regulated categories (each criteria pollutant, hazardous air pollutants, etc.)

8 Possible Air Permit Application (Cont.) Equipment list. Material Safety Data Sheets (MSDS) if required (note: chemical-specific information from mixtures would be listed on usage/ emissions excel spreadsheets). Abatement equipment supplier information, including removal efficiencies.

9 Application Form Usually available from local regulatory agency. Some regulatory agencies require their forms filled out completely. Check to make sure Not Applicable can be used or if you can eliminate forms that do not apply to your operations.

10 Emission Factors/Abatement Word Document Provide all emission factors and how each was derived. Use emission factors that may be used for other regulatory reporting like Greenhouse Gas Reporting Rule, Toxic Release Inventory, etc. Regulatory agency emission factors (e.g., AP-42 for emergency generators and boilers).

11 Emission Factors/Abatement Word Document (Cont.) Point-of-use abatement removal efficiencies. Removal efficiencies for centralized abatement equipment (wet scrubbers, VOC control equipment, etc.).

12 Emission Factors/Abatement Word Document (Cont.) All atoms like C, F, N, S and Si should be accounted for. Process and POU knowledge, chemistry, and testing data are critical in determining which byproducts will be generated. Recommend thinking through what will actually be emitted to atmosphere (e.g., SF 6 may generate numerous byproducts in process, POU abatement, etc.; however, maybe only SF 6, SO 2, and HF will be emitted out of stacks).

13 Emissions Excel Spreadsheets Use excel spreadsheets as easy for fab personnel to use and regulatory folks to review. Develop different excel spreadsheets for (1) gases/ liquid precursors; (2) acids/bases/cmp/ electroplating; (3) organic compounds (isopropanol, photoresists, developers, etc.); (4) natural gas fired equipment (boilers, VOC controls, POU abatement devices, etc.); (5) emergency generators and fire pumps; and (6) emissions summary for each individual pollutant and then summed up for regulatory categories.

14 Emissions Excel Spreadsheets (Cont.) Provide information from MSDSs. Determine if regulatory agency wants maximum or average for weight percents and densities. For potential-to-emit, usually maximum. If total for maximum weight percents is higher than 100%, discuss how regulatory agency wants to list weight percents. The emissions for the six excel spreadsheets are linked so that each change made will update final emissions summary.

15 Equipment List Equipment list likely on application form. List exempt equipment (e.g, insignificant and trivial activities) on equipment list or somewhere else on application to document what equipment is exempt from permitting.

16 Material Safety Data Sheets (MSDS) Only include in application if required, as weight percents and densities are already listed in emissions excel spreadsheets. Review more than components section and physical and chemical properties section. Additional chemical information can be found in other sections (e.g., regulatory information, toxicological information, etc.)

17 Abatement Equipment Suppliers Information Point-of-use abatement equipment (exhaust conditioners) are permitted differently in many locations. Regulatory agency may require detailed supplier information. Usually centralized wet scrubbers and VOC control equipment require detailed supplier information. Review supplier s information carefully.

18 Confidentiality Permit applications are likely public information and competitors may review them for information. Some regulatory agencies allow for two permit applications: public version and confidential version.

19 Some Items to Consider Pre-meeting with regulatory agency permit engineer may be helpful. Very few regulatory agency permit engineers have semiconductor experience. Preparer of permit application should have significant semiconductor process and abatement experience, including process and abatement equipment byproducts. Review work if prepared by consultant.

20 Some Items to Consider (Cont.) VOC control equipment supplier s stated carbon monoxide and nitrogen oxides emissions are usually based only on natural gas combustion; therefore, include additional carbon monoxide and nitrogen oxides emissions from oxidation of VOCs. Silicon dioxide (particulate) will be generated by oxidizing hexamethyldisilazane (HMDS) in VOC control equipment using combustion.

21 Some Items to Consider (Cont.) Other fuels may be used as back-up and should be included in permit application. For example, #2 fuel oil in place of natural gas. Emergency generators and fire pumps may operate using other fuels like natural gas instead of diesel fuel.

22 Some Items to Consider (Cont.) Review byproducts also from POU abatement devices. There could be higher emissions of carbon monoxide, nitrogen oxides, particulate, hydrogen fluoride, etc. POU abatement device and centralized abatement equipment monitoring may be required to ensure compliance.

23 Some Items to Consider (Cont.) Be careful not to permit too high removal efficiencies for abatement equipment. For example, centralized acid scrubbers with low acid gas inlet concentrations typically are much less than 90% efficient for acid gases. Use supplier s information carefully. There are many compounds that have near 0% removal efficiency in centralized wet scrubbers: greenhouse gases, arsine, phosphine, ammonium compounds, etc.

24 Some Items to Consider (Cont.) Since permits may be for several years before needing renewal, meet with fab personnel to try to understand how to permit fab to include future changes. Remember to permit potential-to-emit (PTE) emissions for maximum operational flexibility.