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ESM 595 F

ESM 595 F. Pollution Prevention in the Electronics Industry. Electronics Industry. Fast growing sector of economy Few common appliances and machines could function without electronics Perceived as “pollution-free” since it has no smoke stacks Environmental impacts .

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ESM 595 F

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  1. ESM 595 F Pollution Prevention in the Electronics Industry

  2. Electronics Industry • Fast growing sector of economy • Few common appliances and machines could function without electronics • Perceived as “pollution-free” since it has no smoke stacks • Environmental impacts ...

  3. Semiconductor Manufacture • Crystal Growth • Wafer fabrication • Deposit of active and inactive layers • Oxidation to form silicon oxide • Photolithography • Etching • Addition of impurities for special functions

  4. Crystal Growth

  5. Silicon Wafer

  6. Printed Circuit Board • Patterns of Conductive Material set on a Non-conductive base • Conductive Materials: Cu, Al, Cr, Ni • Non-conductive: Epoxy/paper, phenolic resin, epoxy/glass resin, teflon • Conductor can be added as lines or as a layer which is then etched

  7. Printed Circuit Board • Clean and prepare surface (drilling, burring, solvent wash, abrasive wash, alkaline wash) • Electroless copper plating (thin layer through holes) • Pattern printing and masking • Electroplating • Etching

  8. Circuit Board Assembly • Insert components • Adhere components • Cure adhesive • Solder • Final cleaning

  9. Other Process Considerations • Piping of gases and corrosive liquids • Cooling water to control processing temperature • Deionised water production • Clean room conditions • Handling of process wastes (gas, liquid, solid)

  10. Waste Streams

  11. Waste Streams

  12. Waste Streams

  13. Example: Copper Waste

  14. Environmental Impacts • From Manufacturing • Air emissions • Wastewater • Solids, sludges and Haz wastes • From Product Use • Energy (electrical or batteries) • From Product Disposal

  15. Example: Pager • Disposed due to • end of useful life • obsolescence • To recover useful materials, need to consider: • labor to disassemble • segregated storage & transportation • reprocessing • Balance against scrap value of materials

  16. Example: Pager • Circuit board is sent to a reclamation facility • burn off organic materials (epoxy, paper) • recover metals: Au, Ag, Pt, Pd, Cu, Al, Ni, Cr • Gold may represent less than 1% but account for more than 90% of value • Estimated value of average circuit board is $7 per pound ($3/kg) (1992 prices)

  17. Example: Pager • Other reusable parts • vibrator motor • microprocessor • oscillator crystals • filters • coils • antennae • Valued at $19.28 • Warranty, obsolescence, disclosure

  18. Pollution Prevention Tools • Life-Cycle Assessment/EIA • Product Design • Higher density of transistors in each chip • Higher density Surface Mount Technology vs. conventional plated-hole technology • Use more common plastics • Reduce plastics/metals assemblies • Use built-in plastic or metal clips for assembly

  19. Pollution Prevention Tools • Process Design • Vacuum pack after epitaxy • Iron oxide masks (vs. emulsion masks) • Single solvent systems (recover/reuse) • Water based developer (vs. solvent) • Infrared heating lamps for drying • Filtering plating, etching baths • Dry etching vs. wet etching

  20. Pollution Prevention Tools • Material Selection • Aqueous cleaning materials vs. solvents • Purification of solvents • Eliminate use of CFCs by substitution • Reduce number of acids, and use those that result in non-toxics when neutralized (e.g. HCl vs. Trichloroacetic acid) • Lead-free solder

  21. Pollution Prevention Tools • Operational Factors • Process Control • Preventive maintenance • Monitoring of concentrations in air & water • Materials handling & storage • Inventory control

  22. Pollution Prevention Tools

  23. Pollution Prevention Tools

  24. Waste Stream Processing

  25. Waste Stream Processing

  26. Waste Stream Processing

  27. Waste Stream Processing

  28. Step-by-Step Case Study • Case Study of Pollution Prevention for Printed Circuit Board • Phase I: Preassessment • Step 1: Form audit team & develop objectives • Step 2: List Unit Operations • Step 3: Construct Process Flow Diagrams with emissions and waste streams

  29. Case Study of Pollution Prevention for Printed Circuit Board

  30. Case Study of Pollution Prevention for Printed Circuit Board

  31. Case Study of Pollution Prevention for Printed Circuit Board • Phase 2: Material Balances • Step 4: Determine Inputs • Step 5: Record Water Usage • Step 6: Determine Reuse/Recycle Rates • Step 7: Quantify Process Outputs • Step 8: Characterize wastewater streams • Step 9: Account for gaseous emissions • Step 10: Account for off-site wastes • Step 11: Assemble Input + Output Information

  32. Case Study of Pollution Prevention for Printed Circuit Board

  33. Case Study of Pollution Prevention for Printed Circuit Board

  34. Case Study of Pollution Prevention for Printed Circuit Board

  35. Case Study of Pollution Prevention for Printed Circuit Board • Step 12: Develop Material Balance for each processing area

  36. Case Study of Pollution Prevention for Printed Circuit Board Electroplating Line (Microplate 9000 line)

  37. Case Study of Pollution Prevention for Printed Circuit Board Oxide coating area

  38. Case Study of Pollution Prevention for Printed Circuit Board

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