DFEHS Design for Environment_ He by liaoxiuli1

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									                                        DFEHS
     Design for Environment, Health, and Safety




                     Material contributions by Bob Duffin,
                                       Motorola Corp.

                      1999 Arizona Board of Regents for The University of Arizona



                                                                                             Duffin
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       1
                            What is DFEHS?

• Systematic approach to design, manufacture, use, and
  disposition of products and processes that incorporates
  consideration for EHS impacts
• Management approach for evaluating and mitigating EHS
  concerns at the earliest possible stages of product/process
  design
• Optimization of balance between EHS priorities and design
  quality factors (cost, yield, performance, etc.)
• Ongoing evaluation and continuous improvement

                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       2
                              Driving Forces

• Decreasing cost
   – reduced material consumption, cycle time, regulatory
     resources, delays, etc.
   – reduced operating costs
   – reduced hazardous materials handling costs
         • storage, training, site response, compliance req’s, disposal, etc.


• Achieving sustainability for tools/processes
   – ensures that EHS issues will not be the cause of
     tool/process phase out

                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       3
                     Driving Forces (cont’d)
• Minimizing time to market
  – avoids cost delays at implementation stage of projects
         • permit modifications, EHS review, retrofits, etc.
    – anticipates potential problems with regulatory issues

• Maintaining market share
  – ensures compliance issues for international standards
    (ISO, EMAS, etc.) are addressed

• Increasing market share
   – competitive tool in the marketplace
   – customer/consumer impression of “greenness” matters
                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       4
                     Driving Forces (cont’d)

• Reducing corporate risk factors
   – elimination of liability related to haz-waste
     management
   – early identification of required permit modifications

• Projecting environmental leadership
   – business values



                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       5
   Hot EHS Issues - Semiconductor Industry

• Global Warming
   – 1995: IPCC declared the presence of a human
     influence on global climate
   – GW gases used by the semiconductor industry: PFC’s
         • CF4, C2F6, SF6, NF3, C3F8, CHF3
         • utilized during plasma cleaning, etching
    – Push to develop CVD and etch process that eliminate or
      reclaim PFC emissions



                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       6
 Hot EHS Issues - Semiconductor Industry (cont’d)

• Water Use Reduction
  – Estimated 10,000 gal DI water per day per one 200 mm
    wafer through entire process
  – Ion exchange for DI production - large user of bulk
    chemicals = significant waste
  – Water use can limit new factory location and
    production volume

• Worker Safety
  – Recordables, lost day cases, worker’s comp cases, etc.
                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       7
                           Levels of Analysis

• Device design and process development
   – Individual process steps
   – In-house new tools and existing tool optimization
   – Agreements with suppliers concerning tool design
   – Equipment specifications
   – Entire tool set and process flow

• Manufacturing
  – Facilities integration
  – Ergonomics

                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       8
                                    Case Studies
                                     Motorola Corp.
• Segregated Ammonia Exhaust System
     Problem - Ammonia exhaust routed to acid exhaust system created problems
     with visible plumes and scrubber effluent testing due to ammonia salt
     formation (result of ammonia mixing with acid gases)
     Solution - Retrofit fabs with segregated ammonia exhaust scrubbers
      – Retrofit cost = $3-5 million
      – New fab construction cost = $1-2 million


•     Water Reuse
     Problem - Many wet cleans tools that utilize water are supplied with the proper
     plumbing to recycle the spent water. However, most fabs are not equipped
     with the plumbing network to support water recycle.
     Solution - Retrofit with very low payback
      – Retrofit cost = $4.8-6 million
      – Cost to hook up each wet bench to recycle plumbing - $7500
                                                                                                 Duffin
    NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing       9
                           Case Studies (cont’d)
                                     Motorola Corp.
• Methanol to IPA Conversion
     Problem - Methanol, which is considered a hazardous air pollutant (HAP), is
     used as a solvent in metal etch deveil and photoresist stripping operations.
     Ineffective abatement with current VOC equipment means that the site could
     be subject to a Title V permitting program, which would significantly decrease
     permit flexibility and increase downtime spent on permit modification.
     Solution - Convert processes to use IPA, which is not considered a HAP
      – Saves $300,000 in permitting costs
      – Avoids the need for $1-2 million in specific abatement equipment for the
         methanol


•     Water-Based Photoresist Stripping
       – The switch from a solvent-based stripper system to a water-based system
         resulted in annual savings of $70,000, due to cheaper chemicals and
         reduction in waste treatment steps. In addition, the Thin Film process
         became easier to control.
                                                                                                 Duffin
    NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing     10
                           Case Studies (cont’d)
                                     Motorola Corp.

• Tool Exhaust
       – A new tool for wafer cleans was set to be installed in place of an old
         system. It utilizes HF vapor instead of wet chemistry, followed by an IPA
         dry. The current plumbing was hooked to solvent exhaust, and HF vapor
         was not used in the fab prior to the introduction of this new tool. The start
         up was delayed while ducting modifications were made to plumb the new
         tool effluent to the acid exhaust system.


•     Pump Oil Reclaim
       – A system designed to reclaim synthetic oil in vacuum pumps saved over
         $220,000 during the first two years of use. It consists of rough and fine
         filters to remove acids and other impurities. The cost of new oil is $170-
         179 per quart, while the cost of reclaimed oil is only $0.62 per quart.



                                                                                                 Duffin
    NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing     11
                Consequences of No DFEHS

• Morass of regulatory issues
   – example: air permit process = 18 months in AZ
• Possible non-compliance with new and ever-changing
  regulations
   – 1983 avg. RCRA violation fine = $8,640, 1989 avg.
     avg. RCRA violation fine = $103k, …. 
• Criminal liability for employees and community
• High cost of haz-waste cleanups


                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing     12
                                       Trends

• Global acceptance of DFEHS
• Increased legislation
• Internal design aids
   – Company policies
   – Matrices/questions to answer
   – Flowcharts
• Software tools
   – Example = Computerized Assessment of Relative Risk
     Impacts (CARRI)

                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing     13
                     What can engineers do?

• Reduce:
   – energy and water use, chemicals, etc. in support of
     conservation of natural resources
   – pollution at the source whenever possible
   – the toxicity of chemicals used
   – employee exposure to chemicals
   – the use of chemicals by optimizing processes



                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing     14
            What can engineers do? (cont’d)

• Reuse:
   – previous designs and processes which minimize impact
     on the environment
   – shipping packaging

• Recycle:
   – waste or by-products generated wherever pollution can
     not be reduced to zero at the source
   – purchase recycled products wherever possible


                                                                                              Duffin
 NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing     15

								
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