Transcript Semiconductor Industry Association Worker Health Project

Semiconductor Industry Association
Worker Health Project
Primary Prevention Initiative:
Exploring Opportunities to Further Minimize
Potential Equipment-related Exposures
Nick Filipp PhD, CIH
Principal Consultant
Environmental & Occupational
Risk Management, Inc. (EORM)
February 3, 2005
Agenda
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© 2005 EORM, Inc.
Background
Primary Prevention Initiative
Study Team
Study Participants
Study Approach
Results
Conclusions
Potential Opportunities for
Improvement
Acknowledgements
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Background
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In response to negative publicity surrounding
lawsuits, SIA commissioned a Scientific Advisory
Committee (SAC) to evaluate potential for increased
cancer risks among fab workers
– SAC primary objective: conduct an independent,
objective analysis of whether potential
semiconductor "clean room" chemical exposures
are likely to elevate cancer risk and, based on this
analysis, make appropriate recommendations to
SIA
SAC concluded: no affirmative evidence of increased
risk of cancer for fab population.
SAC also reported: insufficient data exists to conclude
whether exposure to chemicals or other hazardous
materials has or has not increased cancer risk
SAC provided recommendations for further studies.
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Background (cont’d)
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SIA outlined various follow-up actions known
collectively as the “Worker Health Project”
SIA recommendations included Primary
Prevention Initiative (PPI) Tasks
PPI Tasks
– Designed to further strengthen ongoing
efforts to ensure a safe workplace
– Went beyond the SAC's recommendations
– Designed to provide member companies with
a broader base of knowledge to help enhance
their existing worker safety programs.
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Primary Prevention Initiative: Exploring
Opportunities to Further Minimize
Potential Equipment-Related Exposures
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The PPI Committee reviewed the broad spectrum of
chemical operations in the Fab and selected four 200
mm process areas for evaluation:
– Etch
• Metal Etch
• Polysilicon Etch
• Dielectric Etch
– Implant
– Thin Films - CVD
• Metal Deposition
• Dielectric Deposition
• Thermal Oxidation
– Thin Films - Epitaxy
• Silicon Epitaxy
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Study Objectives:
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Identify opportunities for capital equipment
suppliers to demonstrate further hazard
mitigation through changes to normal
operation, preventive and corrective
maintenance procedures and tool design
Identify alternatives that might provide
opportunities to reduce and/or eliminate the
need for administrative controls as the
primary means of preventing unsafe
exposures
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EORM’s Role
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PPI Committee retained EORM to perform an
assessment of these fab areas to identify
further minimization of equipment-related
chemical exposures during preventive and
corrective maintenance
EORM Project Team:
– Nick Filipp, PhD, CIH, Principal Investigator
and Principal Consultant
– Andrew McIntyre, CIH, Managing Principal
– Andrea Sevier, CIH, Senior EHS Consultant
– Patrick Tierney, CIH, Principal Consultant
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Study Participants
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SIA Member Companies
– Participating sites selected based on
availability of equipment included in
the study
• Four Member Companies provided access
for study objectives
– Site EHS personnel provided access to
documentation, technical personnel,
and equipment
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Study Participants (cont)
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Capital Equipment Suppliers
– Participant Companies
• Applied Materials
• ASM of America
• Axcelis Technologies
• Novellus Systems
• Tokyo Electron America
• Varian Semiconductor Equipment Associates
(VSEA)
– Two levels of participation
• Provided access to documentation, technical
personnel, and equipment at their facilities
• Provided access to documentation only
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Study Approach
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Understand Process and Procedures
Identify Potential Chemical Exposures
– Process chemicals
– Primary process by-products
– Secondary process by-products
– Maintenance chemicals
Review maintenance manuals and specifications
Review available qualitative and quantitative exposure
data
Interview process and maintenance engineering and
EHS staff
Observe selected maintenance operations
– Ask a lot of questions
– Record data on JHA tool
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Data Collection Tool
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Study Results
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For the processes studied there were common
considerations with regard to potential for chemical
exposure
Potential sources of exposure:
– Process chemicals
– Reactive species formed during process
– Byproducts formed from reactions of various
species with:
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Each other
Wafer substrate
Materials of construction
Exhaust system components
– Secondary byproducts formed when equipment is
opened to atmosphere
– Maintenance chemicals
Other considerations:
– Parts cleaning
– Preventive maintenance vs. corrective
maintenance
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Study Results - Exposure
Controls
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During normal operation chemical exposure is
primarily mitigated by engineering controls
supplemented with some administrative controls:
– Process contained under reduced pressure
– Chambers and process modules equipped for inert
purging
– Ventilated enclosures for hazardous chemical
distribution systems
– Continuously welded gas delivery lines
– Monitored process exhaust to remove emissions
– Interlocks to place equipment in “safe state”
– Toxic gas monitoring
– Small quantities of chemicals used in each batch
– Operator training
– Detailed SOPs
– PPE
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Chemical exposure is well controlled during normal
operation
– Some instances of low level fugitive emissions
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Study Results - Exposure
Controls
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During maintenance some of the engineering controls
in effect during normal operation are by passed or
shut down. Supplemental engineering controls and
additional administrative controls are implemented:
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Facility provided maintenance exhaust
Portable toxic gas detection equipment
Parts engineered for facile removal/replacement
Means to seal contaminated parts upon removal
Exhausted disassembly and dirty parts storage facilities
Dedicated facility vacuum systems or portable HEPA
vacuums
Development of detailed procedures for maintenance tasks
Cycle purging of toxic gas lines
Cordoning off and evacuating areas prior to maintenance
Training of maintenance personnel (with regard to chemical
hazards)
PPE to prevent dermal contact and inhalation
Project Team noted that end-users have
implemented innovative controls or techniques
used to minimize exposures
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Conclusions
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Existing combinations of engineering,
administrative, and personal protective
equipment controls were effective at
maintaining airborne chemical
concentrations below occupational exposure
limits during normal production operations
and during maintenance.
Opportunities were identified to
– Reduce reliance on procedural controls and
PPE
– Reduce low level fugitive emissions
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Potential Opportunities for
Improvement For Semiconductor
Company Consideration:
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Provide additional exhaust ventilation flow through
the tool, or
Provide portable exhaust ventilation devices for
emissions from open tool components
Introduce air into an enclosed tool to allow chemical
reactions to take place while the process is still
contained
Employ comprehensive approach where QEAs, PPE
assessments and IH air sampling is used to validate
effectiveness of controls
Provide a higher level of EHS guidance in PM
procedural documentation (internal), where
appropriate
Include LOTO procedures for all sources of energy in
maintenance specifications
Expand channels of communication between suppliers
and end users to share innovative EHS practices
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Potential Opportunities for
Improvement For Equipment
Supplier Consideration:
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Evaluate feasibility and advisability of
designing exhaust ventilation through tool
Enable the introduction of air into the
reaction chamber prior to it being opened
Establish a process for communicating new
supplier maintenance manuals to MC
Communicate equipment parts cleaning and
decontamination procedures to MC
Provide precautionary courses of action
when normal process clean steps can not be
completed
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Acknowledgements
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The EORM Project Team would like to acknowledge the fact
that EHS professionals from the equipment suppliers and
member companies participating in this study have been
very active in investigating and researching various health
and safety issues and frequently share their experiences
through publications, presentations, and specialized classes
taught at professional meetings.
The EORM Project Team would also like to gratefully
acknowledge the Production, Maintenance, Product Safety,
and EHS personnel at the participating companies for
providing the opportunity to observe maintenance
procedures, review documentation, and ask endless
questions.
Full EORM Report posted to the SIA Web Page
Reference SIA’s President George Scalise Report on Worker
Health and Discussion on PPI
http://www.sia-online.org/iss_whs.cfm
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