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SEMI F28-1103 © SEMI 1997, 2003 1 SEMI F28-1103 TEST METHOD FOR MEASURING PARTICLE GENERATION FROM PROCESS PANELS This test method was technically approved b y the Gl obal GasesCommittee and is the direct r esponsibility…

SEMI F27-0997 © SEMI 1997, 2003 5

Regulators should be tested in the fully-open condition

(i.e., with the regulator adjusted for minimum pressure

drop). The quantity of published data on regulator

interaction with moisture is limited, and experiments to

investigate the effect of varying the pressure drop

across the regulator are encouraged but are not part of

this test. MFC’s should be tested with a flow control

device upstream and the MFC not actively controlling

the flow through it (usually referred to as the “purge”

setting). It may not be possible to test a given MFC at

the specified flow if the flow rating of the MFC is much

less than the specified flow. As MFC’s are not expected

to vary greatly in performance according to their flow

rating, MFC’s to be tested should generally be chosen

to be compatible with the table. If this is not possible,

then the MFC should be tested at its rated flow (lower

than the flow in the table). This can then be considered

a conservative test, as the MFC operated at higher flow

would be expected to dry down more quickly.

7.3.2 Particle filters with the same size tubing

connectors often have somewhat different sizes and

very different flow ratings. In order to be able to make

reasonable comparisons between the performance of

different filters, it is essential to test filters of similiar

size at the same flow. However, the flow dependence of

the moisture response of particle filters is more

complex than that of tubing, and they must be tested at

more than one flow in order to model their behavior. In

order to meet this requirement and provide data which

can be readily compared with the conditions under

which the filters can be expected to be used in practice,

filters shall be tested at two flows: The first, according

to the size of the connecting tube stubs, the second, to

be 25% of the rated flow of the filter or 50 slm,

whichever is less.

7.3.3 For systems of components, the system shall be

tested at the lowest flow of those determined for each

component in the system considered separately. If the

system includes a filter, it shall be tested at that flow

and additionally, at 25% of the rated flow of the filter or

50 slm, whichever is less.

Table 1 Flow Rate

Tubing Outer Diameter

(nominal)

Flow (all

components)

Flow for Second

Test on Filters

≥ 1/8", < 1/2"

(≥ 3.2 mm, < 12.7 mm)

6 slm

≥ 1/2"

(≥ 12.7 mm)

13 slm

25% of rated flow

or 50 slm

whichever is less

8 Reporting Results

8.1 Complete moisture response curves for all test

specimens and relevant test blanks should be included.

A summary sheet may compare components in terms of

“induction time,” peak height, and/or decay time.

Temperature, pressure, and flow measurements, and as

complete a record as possible of all experimental

variables should be noted.

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.

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 F28-1103 © SEMI 1997, 2003 1

SEMI F28-1103

TEST METHOD FOR MEASURING PARTICLE GENERATION FROM

PROCESS PANELS

This test method was technically approved by the Global GasesCommittee and is the direct responsibility of

the North American Gases Committee. Current edition approved by the North American Regional Standards

Committee on September 25, 2003. Initially available at www.semi.org October 2003; to be published

November 2003. Originally published September 1997.

1 Purpose

1.1 The purpose of this document is to define a method

for testing process panels intended for installation in

high-purity gas distribution systems. Application of this

test method is expected to yield comparable data among

process panels tested for the purposes of qualification

for this installation.

1.2 This document describes a test method designed to

draw comparisons of particulate generation

performance of process panels. This test method

evaluates the cleanliness of process panels in the “as

received” condition as well as under normal operating

conditions. The “as received” test is intended to enable

the user to evaluate the fabrication, cleaning, and

packaging techniques of the manufacturer of the

process panel. The test under actual operating

conditions is intended to allow the user to evaluate the

manufacturer’s component selection as well as the

quality of the panel design. The specific flow rates

described in both test methods are representative of

relatively high flow conditions for a typical process

panel.

2 Scope

2.1 This test method addresses total particle counts

greater than the minimum detection limit (MDL) of the

particle counter and does not consider classifying data

into various size ranges.

2.2 This procedure utilizes a particle counter applied to

process panels typically used in semiconductor

applications. It applies to process gas supply systems

(e.g., gas cabinets) which include a process panel, an

inert purge panel, and a system vent. Both automatic

and manual process panels are within the scope of this

test procedure. Panels, as defined in this test method,

are considered to consist of 6.35 mm O. D. × 0.89 mm

wall (1/4" O.D. × 0.035" wall) tubing and components.

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 test method specifies flow and mechanical

stress conditions considered typical of conditions which

would be expected under moderately aggressive

operating conditions. These conditions should not

exceed those recommended by the manufacturer.

Actual performance under operating conditions at lower

flow rates or less aggressive conditions may differ. This

test method does not address particle generation under

vibrating conditions.

3.2 The test medium is limited to nitrogen, argon, or

clean dry air (CDA). Performance with other gases may

differ.

3.3 The accuracy of the data generated by this method

is limited to the accuracy of the particle measuring

instruments utilized.

3.4 This method is written with the assumption that the

operator understands the use of the apparatus at a level

equivalent to six months of experience.

3.5 This document is not intended as a methodology

for monitoring on-going particulate performance once a

particular process panel has been tested. Also, this

method does not include extended dynamic particle

count testing (particle generation after thousands of

cycles).

3.6 Auto-crossover systems are not within the scope of

this test procedure.

NOTE 1: It should be mentioned that test results from panels

equipped with final outlet filters can differ significantly from

test results from panels without filters.

4 Referenced Standards

4.1 ISO Standards

ISO 14644-1 — Cleanrooms and associated controlled

environments Part 1: Classification of air cleanliness.

1 International Organization for Standardization, ISO Central

Secretariat, 1, rue de Varembé, Case postale 56, CH-1211 Geneva 20,

Switzerland. Telephone: 41.22.749.01.11; Fax: 41.22.733.34.30,

Website: www.iso.ch

SEMI F28-1103 © SEMI 1997, 2003 2

ISO 14644-2 — Cleanrooms and associated controlled

environments Part 2: Specifications for testing and

monitoring to prove continued compliance with ISO

14644-1.

NOTICE: Unless otherwise indicated, all documents

cited shall be the latest published versions.

5 Terminology

5.1 Abbreviations and Acronyms

5.1.1 CDA — Clean, dry air

5.1.2 EP — Electropolished

5.1.3 LPC — Laser particle counter

5.1.4 psi — Pounds per square inch

5.1.5 psia — Pounds per square inch absolute

5.1.6 psid — Pounds per square inch differential

5.1.7 psig — Pounds per square inch gauge

5.1.8 scfm — Standard cubic feet per minute

5.1.9 slpm — Standard liters per minute

5.1.10 SL — Standard liters

5.2 Definitions

5.2.1 background counts — counts contributed by the

test apparatus (including counter electrical noise) with a

spool piece in place of the test object.

5.2.2 Compressed Gas Association (CGA) — also

frequently used to refer to a fitting, as defined and

specified by the Compressed Gas Association, which is

used to connect a gas source cylinder to a panel inlet.

5.2.3 condensation nucleus counter (CNC) — a

discrete particle counting instrument that detects

particles, in a gaseous stream, by measuring light

scattered from droplets grown to measurable size by

condensation of supersaturated vapor upon the

particles.

5.2.4 dynamic test — a test performed to determine

particle contribution as a result of valve actuation or

regulator adjustment in a process panel during normal

operation.

5.2.5 process panels — a gas source control piping

system for delivering process gases as defined in SEMI

F13.

5.2.6 sample flow rate — the volumetric flow rate

drawn by the particle counter for particle detection.

5.2.7 sampling time — the time increment over which

counts are recorded.

5.2.8 source pressure — pressure of the source gas

applied to the cylinder connection at the panel inlet.

5.2.9 spool piece — a null component consisting of a

straight piece of electropolished tubing and appropriate

fittings used in place of the test component to establish

the baseline.

5.2.10 standard conditions — 101.3 kPa, 0.0°C (14.73

psia, 32°F).

5.2.11 static test — a test performed on an as-received

process panel with all valves in the fully-open position.

5.2.12 test duration — total time required to complete

the test procedure.

5.2.13 test flow rate — volumetric flow rate of the test

gas at standard conditions as defined in Section 5.2.10.

5.2.14 test pressure — pressure immediately

downstream of the test panel.

6 Test Procedure

6.1 Test Conditions

6.1.1 Precautions — This test method may involve

hazardous materials, operations, and equipment. This

test method does not purport to address the safety

considerations associated with its use. It is the

responsibility of the user to establish appropriate safety

and health practices and determine the applicability of

regulatory limitations before using this method.

6.1.1.1 Exhaust from the CNC may contain hazardous

and/or flammable vapors and should be properly treated

before being released to atmosphere.

6.1.2 The test is to be conducted at a normal indoor

temperature of between 18°C (64°F) and 26°C (78°F).

6.1.3 Test apparatus must be enclosed in a Class 100

environment (per ISO 14644). Use procedures

necessary to maintain Class 100 when handling test

apparatus and test components.

6.1.4 Care should be taken to protect the test apparatus

from excessive vibration. For example, vacuum pumps

and compressors should be isolated from the system.

6.2 Apparatus and Materials

6.2.1 Test Gas — Clean, dry nitrogen or air is to be

used [minimum dryness −60°C dew point at 790 kPa

(100 psig) and < 10 ppm total hydrocarbons]

6.2.2 Filters — Filters are required to provide

“particle-free” test gas. Each filter must be nine-log

retentive, per manufacturer’s specifications, to 0.02 µm

particles and have a pressure drop of less than 6.9 kPa

(1 psid) at the specified test pressure and flow rate. The

filter must be capable of achieving less than 1 particle