| 1 | Table 1. Specific Comments on Emission Factors and Destruction and Removal Efficiencies (DREs) | | | | |
| 2 | | | | | |
| 3 | Worksheet in EI Workbook | TESU and Description | Chemical or TAC [CASRN or DEQ ID] | Comment | |
| 4 | Gas and Liquid Precursor | Ammonia Use (CVD / Diffusion) | Ammonia [7664-41-7] | Provide documentation to support the assumption of [REDACTED]. | |
| 5 | Gas and Liquid Precursor | Ammonia Use (CVD / Diffusion) | Ammonia [7664-41-7] | Update emission factor in the AQ520 to match the value in the EI Workbook and Emission Factor Documentation (0.9 pounds per year). | |
| 6 | Gas and Liquid Precursor | Arsine Use (Ion Implant) | Arsine [7784-42-1] | Provide documentation to support the assumption of [REDACTED]. | |
| 7 | Gas and Liquid Precursor | Boron Trichloride Use (Etch) | Hydrochloric acid (HCl) [7647-01-0]
Aluminum and compounds [7429-90-5] | Provide documentation to support the assumption that [REDACTED]. | |
| 8 | Gas and Liquid Precursor | Chlorine Use (Etch gas) | HCl [7647-01-0] | The Emission Factor documentation states: [REDACTED]. Include HCl emissions from this process in the Inventory -- currently the only TAC emissions from the Chlorine Use TESU are Cl2. | |
| 9 | Gas and Liquid Precursor | Chlorine Use (Etch gas) | Chlorine [7782-50-5] | In the Emission Factor Documentation, correct the typo in the "Chlorine (Cl2) - Etch Processes" calculation, which should be “lbs HCl/year = (1.028)*(lbs Cl2 used/year)” | |
| 10 | Gas and Liquid Precursor | Hexafluoroethane Use (CVD/Etch gas) | HF [7664-39-3] | Correct the Emission Factor Documentation where it states [REDACTED]. | |
| 11 | Gas and Liquid Precursor | Nitrogen Trifluoride Use (Process 1) (CVD In-situ Plasma Clean)
Nitrogen Trifluoride Use (Process 2)
(CVD Remote plasma clean) | Fluorine gas [7782-41-4] | Update the Emission Factor Documentation to include these processes, and include the emissions calculations in Table 1 of the EI Workbook. | |
| 12 | Gas and Liquid Precursor | Silicon Tetrafluoride Use | Silica, crystalline (respirable) [7631-86-9] | The Emission Factor Documentation indicates that silicon tetrafluoride is used in both CVD and Ion Implant processes and includes POU Removal assumptions for all usage. Confirm that all processes included in this TESU are routed to POU abatement devices with the control efficiencies indicated, or split this TESU into multiple processes with appropriate DREs. | |
| 13 | Gas and Liquid Precursor | Phosphine Use (Process 1) (Ion Implant)
Phosphine Use (Process 2) (Atmospheric CVD) | Phosphine [7803-51-2]
Phosphorus pentoxide [1314-56-3] | Provide documentation to support the assumptions that [REDACTED]. | |
| 14 | Gas and Liquid Precursor | TMPI Use (CVD) | Methanol [67-56-1] | Provide documentation to support the assumption that [REDACTED]. | |
| 15 | Gas and Liquid Precursor | TMPI Use (CVD) | Methanol [67-56-1] | In the Emission Factor Documentation and in the EI Workbook, update the chemical formula for methanol from “CH3O” to “CH4O” or “CH3OH”. | |
| 16 | Gas and Liquid Precursor | Germanium Tetrafluoride Use (Ion Implant) | HF [7664-39-3] | Provide documentation to support this emission factor in the Emission Factor Documentation. | |
| 17 | Gas and Liquid Precursor | N/A | PFCs [489]
HF [7664-39-3] | The Emission Factor Documentation includes emission factors for "Nitrogen Trifluoride (NF3) – Etch/Wafer Cleaning Processes" but these processes are not included in the Inventory -- update the EI Workbook and AQ520 Form to include these emissions. | |
| 18 | Gas and Liquid Precursor | N/A | Silica, crystalline (respirable) [7631-86-9] | The Emission Factor Documentation includes a silica emission factor for Tetraethylorthosilicate (TEOS), but these emissions are not included in the AQ520 Form. Update to add them to the Inventory. | |
| 19 | Acids Bases Plating CMP | Ammonium Hydroxide Use (Acid/Base Chemical Use) | Ammonia [7664-41-7] | Review the requested PTE activity values and emission factor units and update for consistency as needed. [REDACTED]. | |
| 20 | Acids Bases Plating CMP | Chlorine Use Target/Anode Usage (Target/Anode Usage) | Chlorine [7782-50-5] | Review the emission factors in the AQ520 and Emission Factor documentation and update as needed to make them consistent. | |
| 21 | Acids Bases Plating CMP | Nitric Acid (Process 1) | Nitric Acid [7697-37-2] | Update the DRE in the AQ520 and EI Workbook from 96.96 percent to 94 percent. The POU removal is 90% and the centralized control efficiency is 40%. | |
| 22 | Acids Bases Plating CMP
Gas and Liquid Precursor | 50:1 BOE Use (NH3 Emissions)
7:1 BOE Use (NH3 Emissions)
Ammonia Use (CVD / Diffusion)
Ammonium Hydroxide Use (Acid/Base Chemical Use) | Ammonia [7664-41-7] | Clarify the intended control efficiency for ammonia and which processes and scrubbers it will be applied to. [REDACTED]. | |
| 23 | Organic Compounds Used in Photolithography, Cleaning, etc | Multiple | Isopropyl alcohol [67-63-0]
cresols [1319-77-3]
m-cresol [108-39-4]
1-4 dioxane [123-91-1]
n-butyl alcohol [71-36-3]
propylene glycol methyl ether [107-98-2]
propylene glycol methyl ether acetate [108-65-6]
catechol [120-80-9] | The Emission Factor Documentation states "Organic constituent emission factors are estimated based on process knowledge of the chemistries used at the facility, waste stream generated from processes using organic chemistries, and experience with the design of the exhaust management system for organic constituents." Provide specific justification, such as stack test data, published references, or engineering calculations, for each emission factor used in this section that is lower than 1 pound per pound. | |
| 24 | Acid Solutions, Alkaline Solutions and Additional Organic Compounds | Multiple | Ammonium hydroxide solution (as NH3)
antimony
NH3 in BOE
copper sulfate
hydrochloric acid (as HCl)
hydrofluoric acid (as HF)
HF in BOE
nitric acid
phosphoric acid
silicon dioxide
silver nitrate
sodium hydroxide
sulfuric acid
and 3-amino-1,2,4-triazole. | The EF documentation indicates these emission factors "were estimated using fab process experience and engineering estimates." Provide specific justification, such as stack test data, published references, or engineering calculations, for each emission factor used in this section that is lower than 1 pound per pound. Include justification for application of the emission factor to each process and mixture it is applied to. | |
| 25 | Emissions from Sputtering Operations and Anode Usage | All "Target/Anode Usage" TESUs | Metal TACs | Provide engineering calculations to support the assumption that 0.001 lb of emissions per pound use of each constituent. Provide information about how much of the target metal is transferred to the wafers, how much is transferred to the chamber, and how much is sent offsite as solid or liquid waste. Describe the process for cleaning the chamber and eventual fate of the metals transferred to the chamber. | |
| 26 | N/A | Multiple | Metal TACs | Microchip uses targets composed of aluminum, copper, antimony, chromium, and cobalt to deposit metallic films onto wafers. The Inventory only accounts for potential emissions from etching of these metallic substrates in the TESU Boron Trichloride Use (etch) which includes aluminum emissions only. Provide a description of the fate of other metallic substrate materials that are not retained in the wafers, and include any available data related to metals emitted from etch or chamber cleaning processes. | |