semi合集-English.pdf - 第7024页
SEMI S14-0704 © SEMI 2000, 2004 3 5.1.7 hazar d — a conditio n that is a prerequisite to a mishap. 5.1.8 hazar dous volt age — unless otherwise defined by an appropriate internation al standard applicable to th e equipme…
SEMI S14-0704 © SEMI 2000, 2004 2
3.4 This document applies to equipment in its scope
when the equipment is used in the environment
specified by the equipment supplier. Specifically, it
does not apply to the behavior of equipment when it is
subject to an external fire.
3.5 This document is not intended to be used to assess
compliance with regulatory requirements, nor is it
intended to be adopted as regulation.
3.6 Because of these limitations, it may be appropriate
for purchasers of equipment to specify the applicable
codes and standards and the acceptable level of residual
risk.
NOTE 3: Applicable regional, and national codes, inter-
national regulations, and the equipment manufacturer’s and
user’s requirements must also be considered. When a conflict
exists, the regional and national codes take precedence.
4 Referenced Standards
4.1 SEMI Standards
SEMI E10 — Specification for Definition and
Measurement of Equipment Reliability, Availability,
and Maintainability (RAM)
SEMI E70 — Guide for Tool Accommodation Process
SEMI S2 — Environmental, Health, and Safety
Guideline for Semiconductor Manufacturing Equipment
SEMI S7 — Safety Guidelines for Environmental,
Safety, and Health (ESH) Evaluation of Semiconductor
Manufacturing Equipment
SEMI S10 — Safety Guideline for Risk Assessment
and Risk Evaluation Process
4.2 NFPA Documents
1
National Fire Protection Association: NFPA 12 —
Standard on Carbon Dioxide Fire Extinguishing
Systems
National Fire Protection Association: NFPA 13 —
Standard for the Installation of Sprinkler Systems
National Fire Protection Association: NFPA 72 —
National Fire Alarm Code
National Fire Protection Association: NFPA 2001 —
Standard on Clean Agent Fire Extinguishing Systems
4.3 Factory Mutual Document
2
Factory Mutual Research Corp.
Standard 4910 — Clean
Room Materials Flammability Test Protocol
1 National Fire Protection Association, 1 Batterymarch Park, Quincy,
MA 02269, Website: www.nfpa.org
2 Factory Mutual Research Corp., 1151 Boston-Providence Turnpike,
Norwood, MA 02062, phone: 781-762-4300, fax: 781-762-9375,
website: http//www.factorymutual.com
4.4 Underwriters Laboratory Documents
3
Underwriters Laboratory Standard 94 — Tests for
Flammability of Plastic Materials for Parts in Devices
and Appliances
Underwriters Laboratories Standard 746A — Polymeric
Materials - Short Term Property Evaluations
Underwriters Laboratories Standard 746B — Polymeric
Materials - Long Term Property Evaluations
Underwriters Laboratories Standard 746C — Polymeric
Materials - Use in Electrical Equipment Evaluations
NOTICE: Unless otherwise indicated, all documents
cited shall be the latest published versions.
5 Terminology
5.1 Definitions
5.1.1 accredited testing laboratory — an independent
organization dedicated to the testing of components,
devices, or systems; competent to perform evaluations
based on established safety standards and recognized by
a governmental or regulatory body. [SEMI S2]
5.1.2 cleanroom — a confined area in which the
humidity, temperature, particulate matter, and
contamination are precisely controlled within specified
parameters. [SEMI E70]
5.1.3 combustible liquid — a liquid that will burn and
has a flash point at or above 37.8° C (100° F).
5.1.3.1 For the purpose of this guideline, a combustible
liquid, when used by a system capable (under normal or
single-fault conditions) of heating it above its flash
point, is considered a flammable liquid.
5.1.4 combustible material — for the purpose of this
document, a combustible material is any material which
does not meet the definitions in this section for
noncombustible materials.
NOTE 4: A list of criteria, guidelines and standards that may
be used to evaluate the fire properties of materials is included
in Appendix 2.
5.1.5 downtime — the time when the equipment is not
in a condition, or is not available, to perform its
intended funtion. It does not include any portion of non-
scheduled time. [SEMI E10]
NOTE 5: Downtime may be considered according to the
definition of SEMI E10, assuming commited availability of
the parts in question.
5.1.6 flammable liquid — a liquid having a flash point
below 37.8° C (100° F).
3 Underwriters Laboratory, 333 Pfingsten Rd, Northbrook, IL 60062
SEMI S14-0704 © SEMI 2000, 2004 3
5.1.7 hazard — a condition that is a prerequisite to a
mishap.
5.1.8 hazardous voltage — unless otherwise defined by
an appropriate international standard applicable to the
equipment, voltages greater than 30 volts rms, 42.4
volts peak, 60 volts dc are defined in this document as
hazardous voltage.
NOTE 6: The specified levels are based on normal conditions
in a dry location environment.
5.1.9 ignition energy — sufficient energy to ignite a
combustible material. The energy required depends on
the form of the energy and the composition and form of
the combustible material.
NOTE 7: The combustible material may be solid, liquid, or
gas.
5.1.10 likelihood — the expected frequency with which
a mishap will occur. Usually expressed as a rate (e.g.,
events per year, per product, per wafer processed).
5.1.11 mishap — an unplanned event or series of
events that results in death, injury, occupational illness,
damage to or loss of equipment or property, or
environmental damage.
5.1.12 noncombustible material — a material that, in
the form in which it is used and under the conditions
anticipated, will not ignite, burn, support combustion,
or release flammable vapors when subjected to fire or
heat. Typical noncombustible materials are metals,
ceramics, and silica materials (e.g., glass and quartz).
5.1.13 process chemicals — solids, liquids, and gases
used in the normal use of the equipment included in the
scope of this document.
NOTE 8: Solids, liquids, and gases used in the maintenance
procedures (e.g., isopropanol used as a cleaning agent)
specified by the equipment supplier should be considered as
well as those used in operation.
5.1.14 pyrophoric material — a chemical that will
spontaneously ignite in air at or below a temperature of
54.4° C (130° F).
5.1.15 residual risk — that risk which remains after
engineering, administrative, and work practice controls
have been implemented.
5.1.16 risk — the expected losses from a mishap,
expressed in terms of severity and likelihood.
5.1.17 safe shutdown condition — a condition in which
all hazardous energy sources are removed and
hazardous production materials are removed or
contained, unless this results in additional hazardous
conditions.
5.1.18 semiconductor manufacturing process — those
manufacturing steps which are part of the creation of
active or passive electrical devices on a semiconducting
wafer, including the deposition of passivation layers
after final metallization, but excluding testing and
dicing.
5.1.19 severity — the extent of the worst credible loss
from a mishap caused by a specific hazard.
5.1.20 supervisory alarm — an alarm indicating a
supervisory condition.
5.1.21 supervisory condition — a condition in which
action or maintenance is needed to restore or continue
proper function.
5.1.22 trouble alarm — an alarm indicating a trouble
condition.
5.1.23 trouble condition — a condition in which there
is a fault in a system, subsystem or component that may
interfere with proper function.
6 Fire Risk Assessment
6.1 Overview
6.1.1 This section provides criteria for evaluation of
the risks associated with several types of fire hazards.
6.1.2 For each identified hazard described in Section 6,
the evaluator should analyze the contributing, causal,
and mitigating factors. The evaluator should also
review any assessment of the material, component, or
equipment as a whole by an accredited testing
laboratory.
6.1.3 The risk assessment should include both normal
operation and the consequence of reasonably foresee-
able, single-point failures within the equipment. It
should not include exposure to fire or external ignition
sources not within the intended use environment.
6.1.4 Certifications by an accredited testing laboratory
of materials, components, or the equipment as a whole
may be used in the fire risk assessment. However, such
certifications are valid only to the extent that the
conditions of use for the certification correlate to the
conditions of use for the equipment whose fire risk is
being assessed.
NOTE 9: For example, a personal computer certified to IEC
60950 might be incorporated into equipment for use as a
controller. The material flammability requirements of IEC
60950 may or may not be sufficient for this use of the
personal computer, depending upon its exposure to oxidizers
and external sources of ignition when incorporated into the
equipment. Also, the levels of smoke tolerable in the
environment for which a general industry standard was
written may exceed those tolerable in semiconductor
manufacturing cleanrooms. Furthermore, if the equipment is
SEMI S14-0704 © SEMI 2000, 2004 4
intended to be used in a potentially explosive atmosphere, the
certification to IEC 60950 would not sufficiently control its
risk of being a source of ignition.
6.1.5 The consequences and the probability of fire
from each identified hazard should be assessed and
rated, as described in SEMI S10. See Appendix 1 for
the criteria used for the assignments of Severity,
Likelihood and Risk in this document.
6.1.5.1 The assigned Severity and Likelihood and
resulting Risk category should be recorded as part of
the analysis.
6.1.5.2 For those hazards for which the Risk depends
on the conditions of use or use environment, the
equipment supplier should make and state appropriate
assumptions. If the equipment supplier is unable to
make appropriate assumptions as to the Likelihood
because it depends predominantly on factors in the
users' sole control (e.g., adherence to specified
procedures), the supplier should state that and provide
an estimate of the Severity.
NOTE 10: The facilities requirements on which the risk
assessment depends are to be specified by the equipment
supplier.
6.1.6 For fire to occur, there must be a fuel, an oxidizer
and a source of ignition. Elimination of any of these
factors eliminates the risk of fire. Similarly, the
Severity, Likelihood and Risk of a fire can be reduced
by reducing one or more of these elements
appropriately.
6.1.7 It is important to remember that there are often
implicit oxidizers (e.g., room air) and sources of
ignition (e.g., room temperature for a pyrophoric
material).
6.1.8 The fire risk assessment should include the
judgement of a qualified (as described in SEMI S7)
party to determine the level of detail of the assessment.
That party may group similar hazards for assessment
and reporting.
NOTE 11: Such grouping could include, for example, all of
the knobs and buttons of similar materials into one group, the
heated surfaces into a second, and the several flammable
liquids with similar properties into a third.
6.2 Fuels
6.2.1 Fuels include all those materials capable of
reacting with an oxidizer in a fire. The risks of both the
materials of which the equipment is constructed and the
process chemicals used in it should be assessed.
6.2.2 Materials of Construction
6.2.2.1 The risk assessment should include all of the
materials of construction, regardless of quantity or
application.
NOTE 12: This includes small parts, such as knobs, buttons,
electrical contactors, terminal strips, circuit boards, signal
wire and power wiring as well as large components, modules
(such as mini-environments) and subassemblies.
NOTE 13: Some of the smallest components can create a
high risk, as in the potential for ignition by adiabatic
compression of fluoropolymer seats in high pressure oxygen
valves.
NOTE 14: The assessment can be simplified by grouping
similar items together. Example 1: wiring that has the same
type of insulation. Example 2: knobs, switches, handles and
latches made from similar polymers. Identified groups should
include their approximate total mass.
6.2.2.2 In assessing the risk, the evaluator should
consider:
• the size of each component,
• the total quantity and distribution of similar
components,
• the inherent properties of the material, such as
ignitability, flame spread, heat of combustion, and
byproducts (See Appendix 2 for guidance on
evaluation of these properties.),
• the exposure to oxidizers, and
• the exposure to ignition sources.
NOTE 15: The specification control of materials used in
approved electrical components should also be considered.
Approvals may allow for substitution of many materials with
equivalent flammability ratings.
NOTE 16: The inherent properties of materials affect two
types of risk within the equipment: flame spread risk and
contamination risk (i.e., smoke damage from combustion
byproducts). In the case of electrical and electronic
components used in assemblies and equipment that are
constructed and used in accordance with applicable standards
(e.g., IEC 61010-1, IEC 60204-1), flame spread risk may be
adequately controlled by the standard, and detailed
assessment of the material properties of such components that
affect flame spread may not be warranted. However, a
significant contamination risk could still remain (e.g., a
standard may allow a component mounted on a printed circuit
board to fail and burn, as long as the burning remains local to
the printed circuit board) and warrant a detailed assessment of
related material properties of the components. The level of
detail of the assessment may also be affected by the
mitigation method chosen (see Section 7).
6.2.3 Process Chemicals
6.2.3.1 This portion of the risk assessment should
include all of the process chemicals expected (based on
the equipment supplier' s recommended or baseline
processes) to be used in the equipment. It should also
include flammable and combustible wastes generated or
collected within the equipment and fluids in the
equipment which are required for its operation but