1. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 1 Environmental Impacts of Manufacturing Stephen P. Beaudoin Arizona State University  1999 Arizona Board of Regents for The University of Arizona

2. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 2 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing $1,000,000 Questions How does one assess environmental “soundness” of exisiting processes? –Waste Audit How does one assess environmental consequences of processes? –Environmental Impact Assessment (EIA) How does one assess and compare environmental impacts of real and proposed/improved processes? –Life Cycle Analysis (LCA)

3. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 3 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Waste Audits - Objectives Develop understanding of the actual operating processes in a facility or unit operation Identify regions where waste is generated Guide to environmental optimization of process 6 steps

4. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 4 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Waste Audits (cont’d) 1) List all unit operations in process of interest CMP unit operations: –DI water preparation –slurry mixing –chemical mixing –polish tool –buff tool –wafer transport line –brush cleaning tool –megasonic tank –SRD (spin rinse dryer)

5. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 5 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Waste Audits (cont’d) 2) Construct process flow diagrams easy for case of CMP and post-CMP cleaning 3) Determine resource usage raw materials/feeds used in each process/unit operation analysis of process specifications and actual process data many subtle materials (air, water) startup wastes

6. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 6 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Waste Audits (cont’d) 4) Determine storage/handling losses invoices can be compared to actual operating data spillage, spoilage, bad feed wastes identified 5) Quantify levels of waste reuse easy for CMP (none) 6) Quantify process outputs products, wastes

7. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 7 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Waste Audits (cont’d) Results –awareness of wastes, both obvious and hidden, in process –ability to optimize process to minimize environmental impact Questions: waste audit of CMP/post-CMP train –Where do wastes come from in CMP/post-CMP cleaning? –What could have the highest impact for reducing waste? –Would process performance be affected? –Which change could reduce the waste with the least impact?

8. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 8 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Environmental Impact Assessment Prioritization of concerns for environmental impacts of processes and appropriate planning to minimize impacts Required by law in U.S. for many new manufacturing projects –mandated contents –interpreted and enforced by courts –government approves or disapproves project –public can challenge in court 4 stages

9. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 9 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Environmental Impact Assessment (cont’d) 1) Process screening - determines which aspects of existing or planned process must be evaluated a process step that generates slurry waste may be more important that one that generates DI water waste 2) Scoping - determines key issues to be considered CMP generates basic wastewater immediate concern: effect of pH on natural waters or treatment loop long-term concern: effects of neutralization wastes

10. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 10 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Environmental Impact Assessment (cont’d) 3) Statement Preparation - the impact of each waste is assessed soil, water, air, wildlife, and people considered evaluated over appropriate time scales 4) External review - the community evaluates the EIA independent review by local community, government, academia –ensures that the statement is accurate, objective all EIA’s must be reviewed

11. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 11 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Environmental Impact Assessment (cont’d) Mandated contents of EIA: –state of present environmental condition –features of project –effects of project –ways to minimize effects –residual impacts of project Must be comprehensible to the general public

12. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 12 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Environmental Impact Assessment (cont’d) Criteria for choosing projects that require EIA’s: –Lists: certain types of projects always require EIAs –Project thresholds: exceeding threshold values of project cost, production, or land use can mandate EIA Sensitive area criteria - based on ability of environment to handle project and wastes Matrix criteria - all project activities and impacts listed on a matrix –activities: site investigation, preparation, construction, operation and maintenance, future and related activities –impacts: physical, chemical, ecological, aesthetic, social

13. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 13 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Environmental Impact Assessment (cont’d) Sensitive area criteria - based on ability of environment to handle project and wastes Matrix criteria - all project activities and impacts listed on a matrix –activities: site investigation, preparation, construction, operation and maintenance, future and related activities –impacts: physical, chemical, ecological, aesthetic, social

14. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 14 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Life Cycle Analysis Evaluation of entire life of a product –cycle = material acquisition to final product disposal Tool to identify and evaluate opportunities to reduce environmental impacts of products, processes, packaging, materials, and activities Important in ISO 14000, Product Stewardship 7 steps

15. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 15 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Life Cycle Analysis (cont’d) 1) Define scope and purpose of process 2) Set system boundaries primary systems: activities that directly contribute to making, using or disposing of a product secondary systems: auxiliary processes that contribute to making or doing something in the primary sequence Good use of LCA - to assess environmental impacts of changes in CMP processing methods Question: What is a primary, secondary and ternary process for CMP?

16. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 16 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Life Cycle Analysis (cont’d) 3) Inventory checklist outlines all decision areas to be considered in the analysis Guides data collection and analysis Decision areas: –purpose, system boundaries, geographic scope, types of data used, data collection or synthesis methods, data quality measures, presentation of results

17. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 17 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Life Cycle Analysis (cont’d) 4) Peer review guarantees validity of study internal or external reviewers financially supported by EPA possible comment areas: –scope/boundaries methodology, data acquisition/compilation methodology, validity of assumptions and results, method of communication of results

18. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 18 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Life Cycle Analysis (cont’d) 5) Gather data depending on scope and boundaries, may have to go all the way to raw materials acquisition for each chemical used in process remember to include data on materials required to maintain and use your product, and on the final fate of your product 6) Normalize data all data must be evaluated on a common scale (per wafer, per machine per wafer, per hour, per liter slurry...)

19. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 19 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Life Cycle Analysis (cont’d) 7) Generate mathematical model of process allows effects of changes in operating techniques to be compared in terms of their environmental impacts Question: outline the LCA for an oxide polishing process

20. NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing Beaudoin, et al. 20 Summary: Life Cycle Analysis By following the analysis presented, we now have a tool that can be used to evaluate the true impact of a process –can choose the best process from an environmental perspective –avoid transferring wastes from one medium to another