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SEMI F75-1102 © SEMI 2002 8 Table 1 UPW Sy stem Test Parameters, Sa mpling Points and Recommended Monitoring Fre quency for Assuring Good UPW Sy stem Operation Type of Water Source Incoming Feed pre RO filters Pre RO Pos…

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SEMI F75-1102 © SEMI 2002 7
(PFA and PVDF) components and are continuously
leached into the UPW streams. Plastic lined metal
components such as pumps, storage tanks, and other
UPW processing vessels may develop pinholes, thereby
leaching out heavy metal impurities into the UPW
system.
8.9.5 Contaminants from Feed Water
8.9.5.1 The alkali metals (Na, K), alkali earths (Mg,
Ca) and Fe comprise the bulk elements of most natural
waters, and play a significant role in bulk water
chemistry including hardness, alkalinity and total
dissolved solids. Of these elements, sodium is the most
abundant and is present in final filter UPW at sub-ppb
level. Highly charged metals (Al, Fe, and Mn) have the
potential to coagulate and foul RO membranes, and Ba
and Sr can cause scaling of the RO and ion exchange
resins.
8.9.6 Priority Metals in Semiconductor Processing
8.9.6.1 Certain processing steps expose a wafer to
contamination from UPW in a unique way. Metals
from incoming materials (e.g., chemicals, wafers, etc.),
deteriorating wafer processing equipment, and new
processes and materials for deposited circuit layers can
lead to cross contamination and high concentrations of
metals “gettering” on the silicon wafer surface. Testing
for metals in the UPW at POU (e.g., the rinse bath) may
be important in identifying and preventing sources of
metal contamination on the wafer. Certain other
elements, calcium, magnesium and aluminum, have an
increased ability to contaminate the oxides of wafers.
There may be other metals that, depending on the
semiconductor process, can also act as harmful
contaminants.
8.9.7 Radioactive Elements
8.9.7.1 Radioactive elements such as uranium and
thorium can cause soft X-ray damage to devices when
present at ppt levels. These elements are detectable in a
full ICP-MS scan.
9 Typical Monitoring Programs
9.1 On-Line Monitoring
9.1.1 On-line monitors for UPW are readily available
from a variety of manufacturers. Before selecting an
instrument for on-line monitoring an evaluation should
be made about 1.) sensitivity of measurements, 2.)
accuracy of the measurements, 3.) reproducibility of the
measurements, 4.) calibration protocols for the
instrument, 5.) zero count for the instrument (particle
counters) and 6.) instrument cost and reliability.
9.1.2 If on-line monitors are not available at critical
sampling points, or the sensitivity of the on-line
monitor is not sufficient to accurately measure at the
required levels, grab samples may be taken and sent to
a qualified laboratory for equivalent testing. This off-
line sampling and testing requires special apparatus and
trained personnel. A clear understanding of the limits of
each method is required before its application.
9.1.3 All on-line monitoring requires clean and tight
sample port connections in order to eliminate false
counts.
9.2 Testing at critical sampling points, such as point-
of-use, requires special sampling apparatus and trained
personnel. The enclosures and mini-environments
around wet benches that are designed to prevent
accidental access and to isolate human contamination
from the wafer can make it difficult to sample the bath.
However, contamination-free sampling can be done in a
safe way using high purity fluoropolymer apparatus and
trained qualified personnel.
9.3 The utilization of unbiased, independent and
experienced personnel in obtaining data at critical
sampling sites with the UPW system where on -line
instrumentation is not available is essential in
determining the overall performance of the UPW
system.
9.4 See Table 1, “UPW System Test Parameters,
Sampling Points, and Recommended Monitoring
Frequency for Assuring Good UPW System Operation”
for sample point and monitoring frequency
recommendations.
SEMI F75-1102 © SEMI 2002 8
Table 1 UPW System Test Parameters, Sampling Points and Recommended Monitoring Frequency for
Assuring Good UPW System Operation
Type of
Water
Source
Incoming
Feed pre
RO filters
Pre RO
Post RO
prefilters
UPW
Post RO
UPW
Post Ion
Exchange
UPW
Post Final
Filter
UPW
Return Loop
UPW
POU Tools
(Recommended)
Resistivity - Continuous
(Conductivity)
Continuous
(Conductivity)
Continuous
(Conductivity)
Continuous
(Conductivity)
Continuous
(
Conductivity)
-
TOC Bi-Weekly Bi-Weekly Continuous Continuous Continuous Continuous Bi-Weekly
Particles
OPC
Monthly Monthly Monthly Continuous Continuous Continuous Monthly
Particle
SEM
- - - Bi-monthly Monthly Bi-monthly Monthly
Bacteria Biweekly Biweekly Biweekly Biweekly Weekly Weekly Bi-weekly
Dissolved
Silica
Monthly Monthly Monthly Continuous Continuous Continuous Monthly
Total
Silica
Monthly Monthly Monthly Bi-weekly Weekly Weekly Bi-weekly
NVR - - - Continuous Continuous Continuous -
Sodium - - - Continuous Continuous Continuous -
Boron Monthly Monthly Monthly Quarterly Weekly - -
Anions &
Cations
Monthly Monthly Monthly Bi-weekly Bi-weekly Bi-weekly -
Critical
Ions
1
- - - - - - Bi-weekly
Trace
Metals-
Critical
2
Elements
- - - Bi-weekly - - Bi-weekly
Trace
Metals-
Full Scan
Quarterly Quarterly Quarterly Quarterly Monthly Monthly -
1
Critical Ions include Chloride, Fluoride, and Ammonium.
2
Critical Elements include Al, Ca, Cr, Cu, Fe, Mg, Ni, Na, and Zn
NOTE 7: The frequency noted for these parameters is not intended to assure against excursions due to improper maintenance
procedures or other external means of system contamination.
NOTICE: SEMI makes no warranties or representations as to the suitability of the standards set forth herein for
any particular application. The determination of the suitability of the standard is solely the responsibility of the user.
Users are cautioned to refer to manufacturer’s instructions, product labels, product data sheets, and other relevant
literature respecting any materials mentioned herein. These standards are subject to change without notice.
The user’s attention is called to the possibility that compliance with this standard may require use of copyrighted
material or of an invention covered by patent rights. By publication of this standard, SEMI takes no position
respecting the validity of any patent rights or copyrights asserted in connection with any item mentioned in this
standard. Users of this standard are expressly advised that determination of any such patent rights or copyrights, and
the risk of infringement of such rights, are entirely their own responsibility.
Copyright by SEMI® (Semiconductor Equipment and Materials
International), 3081 Zanker Road, San Jose, CA 95134. Reproduction o
the contents in whole or in part is forbidden without express written
consent of SEMI.
SEMI F76-0303 © SEMI 2003 1
SEMI F76-0303
TEST METHOD FOR EVALUATION OF PARTICLE CONTRIBUTION
FROM GAS SYSTEM COMPONENTS EXPOSED TO CORROSIVE GAS
This test method was technically approved by the Global Gases Committee and is the direct responsibility of
the North American Gases Committee. Current edition approved by the North American Regional Standards
Committee on November 22, 2002. Initially available at www.semi.org December 2002; to be published
March 2003.
1 Purpose
1.1 This is a test method to compare gas handling
components for potential particle generation in
corrosive gas service. It is intended as a practical
means of generating performance data for a group of
components to be compared in a selection process.
2 Scope
2.1 This method applies to valves, particle filters, and
low pressure regulators.
NOTICE: This standard does not purport to address
safety issues, if any, associated with its use. It is the
responsibility of the users of this standard to establish
appropriate safety and health practices and determine
the applicability of regulatory or other limitations prior
to use.
3 Limitations
3.1 This method is not intended to provide insight into
fundamental corrosion mechanisms.
3.2 Since the test is to be conducted on fully functional
gas system components, it is not designed to determine
the suitability of specific materials of construction for
corrosive gas service. Such factors as component
design, flow path, weld quality, cleanliness of
construction and manufacturing methods can impact the
results of this test making the material of construction
only one of many factors.
3.3 This method is not designed to provide reliability
or failure data. It is expected that the data produced
will be relative; that is, the data will be most useful
when groups of components are compared to each
other.
3.4 This method is not designed to evaluate parameters
besides particle contribution, for instance leak rate or
regulator drift.
3.5 Components to be tested must be capable of
withstanding the bake temperature of 100°C for filters
and 70°C for valves and regulators.
3.6 This test applies to HCl which is a reducing
environment. Results may not be indicative of
performance in corrosive oxidizing environments such
as Cl
2
.
4 Referenced Standards
4.1 SEMI Standards
SEMI C3.49 — Standard for Bulk Nitrogen (N
2
),
99.99999% Quality
SEMI E66 — Test Method for Determining Particle
Contribution by Mass Flow Controllers
4.2 ASTM Standard
1
ASTM F1394-92 — Standard Test Method for
Determination of Particle Contribution from Gas
Distribution System Valves.
4.3 SEMATECH Documents
2
SEMASPEC #93021510A-STD — Test Method for
Determination of Particle Contribution by Low Pressure
Regulators in Gas Distribution Systems.
SEMASPEC #93021511A — Test Method for
Determination of Particle Contribution by Filters in Gas
Distribution Systems.
NOTICE: Unless otherwise indicated, all documents
cited shall be the latest published versions.
5 Terminology
5.1 Definitions
5.1.1 cycle purge — a procedure which employs
alternating cycles of vacuum and pressure for the
purpose of evacuating a gas system or a portion of a gas
system of impurities or active gases.
5.1.2 particle filter — a device that removes small
particles from a gas stream with high efficiency.
5.1.3 point-of-use purifier — an inline device that
removes homogeneous impurities such as moisture and
oxygen gases. An integral particle filter is typically
included in the same housing to remove particles.
1 American National Standards Institute, 1819 L Street, NW, Suite
600, Washington, DC 20036, website: www.ansi.org
2 SEMATECH, 2706 Montopolis Drive, Austin, TX 78741, website:
www.sematech.org