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SEMI F76-0303 © SEMI 2003 2 5.1.4 regulator — a valve desi gned to redu ce a high incoming pressure to a lower ou tlet pressure by automatically opening to allo w flow until a desired, pre-set pressure on the outlet side…

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

4 Referenced Standards

4.1 SEMI Standards

SEMI C3.49 — Standard for Bulk Nitrogen (N

99.99999% Quality

SEMI E66 — Test Method for Determining Particle

Contribution by Mass Flow Controllers

4.2 ASTM Standard

ASTM F1394-92 — Standard Test Method for

Determination of Particle Contribution from Gas

Distribution System Valves.

4.3 SEMATECH Documents

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

SEMI F76-0303 © SEMI 2003 2

5.1.4 regulator — a valve designed to reduce a high

incoming pressure to a lower outlet pressure by

automatically opening to allow flow until a desired,

pre-set pressure on the outlet side is reached, and then

automatically throttling to stop further pressure

increase.

5.1.5 valve — a device that controls the flow or

pressure of a gas. Valve functions can include shut-off,

metering, backflow prevention, and pressure relief.

6 Summary of Method

6.1 This test method is designed to provide comparative

results for similar components. It is not intended to

replicate process condition or actual use conditions.

Components will be compared for their particle

shedding performance after being exposed to moisture

and corrosive gases, in this case hydrogen chloride

(HCl) gas. The component will be exposed alternately

to corrosive gas and then to moist 100 ppm nitrogen gas

several times. The particle shed performance before

and after exposure will be compared. The overall test

sequence is outlined in Figure 2.

7 Apparatus

7.1 Corrosive Gas Exposure Apparatus

7.1.1 The corrosive gas exposure will be carried out

using the apparatus shown in Figure 1.

7.1.2 Moisture Generator — Moisture generation is

achieved using a permeation-source-type moisture

generator. The permeation source should be selected to

provide 100 ppm H

O in a flow of 500 sccm nitrogen.

Records should be kept on the age of the permeation

source so that a reliable source of moisture can be

maintained.

7.1.3 Vacuum Generator — A Venturi or similar

device capable of producing a rough vacuum of 85000

pascals (25 inches of mercury).

7.1.4 Point of HCl Introduction — The point at which

gaseous hydrogen chloride HCl and N

join the system

(point A in Figure 1) should be designed so that the

dead volume between the check valves is minimized.

The check valves following V1 and V2 should be

nearly joined to each other so as to minimize this

volume.

CORROSIVE GAS EXPOSURE

MOISTURE

GENERATOR

TEST PIECE

SCRUBBER

ANALYZER

PORT

N2 purifier

HCl

PURIFIER

APPARATUS

HCl

vacuum

generator

Figure 1

Corrosive Gas Exposure Apparatus

Legend to figure 1

SYMBOL LEDGEND

Mas Flow Contoller

Impurity Removal Purifier

Particle Removal Filter

Pneumatically Actuated Valve

Check Valve

8 Reagents and Materials

8.1 Nitrogen — Nitrogen with less than 50 ppbv

moisture is to be used. This can be accomplished with

a point-of-use purifier as shown in Figure 1 or by using

99.99999% quality bulk nitrogen according to SEMI

C3.49.

8.2 Hydrogen Chloride — Gaseous HCl should contain

less than 1 ppmv H

O. The HCl purifier shown in

Figure 1 is optional unless the source gas contains

greater than 1 ppmv H

SEMI F76-0303 © SEMI 2003 3

PARTICLE

CLEANLINESS TEST

REPEAT FOR A TOTAL

OF 8 TIMES

HOLD STATIC IN HCl

FOR 16 HOURS

RUN EXPOSURE

SEQUENCE ONCE

PER HOUR 6 TIMES

COOL OVERNIGHT

UNDER N2 PURGE

BAKE 2 HOURS

UNDER N2

INSTALL IN SYSTEM

START

FINAL DRY N2 PURGE

CYCLE PURGE 30

CYCLES

DRY N2 PURGE FOR

2 HOURS

EVALUATE PARTCLE

CLEANLINESS IN N2

REMOVE AND CAP

SAMPLE IN GLOVE

BAG

DONE

Figure 2

Test Flow

9 Safety Precautions

9.1 This method involves the use of hazardous

materials. The user should be experienced in the

handling and use of corrosive specialty gases.

9.2 Safety precautions should include, but are not

limited to:

• continuous air monitoring for HCl in the working

environment as well as the ventilated enclosure.

• SCBA or other supplied air respiratory protection

capable of use in gas exposure levels that may

exceed immediately dangerous to life and health

(IDLH) levels should be used during cylinder

installation and start-up.

• Complete enclosure of the HCl exposure apparatus

in a forced-ventilation cabinet.

• The user should consult the safety, health and

environmental personnel at their site for advice on

appropriate personal protective equipment,

monitoring and ventilation requirements.

10 Test Specimen

10.1 Starting Condition — The test specimen should

be a new component in its original packaging as

supplied by the manufacturer.

10.2 Fittings — The component must have either 1/4″

face seal connections or be of a surface mount design

with all metal seals.

10.3 Sample Size — The number of samples to be

tested is to be determined by the user depending upon

their test objectives. It is beyond the scope of this

method to determine a statistically valid sample size,

however it is recommend that multiple samples of each

type are tested.

11 Preparation of Apparatus

11.1 Mass Spectrometer-based leak checking of the

HCl exposure system after assembly, after the

installation of each test component and after opening

any connection.

11.2 Before each experiment and during idle times, the

apparatus is to be kept in a constant purge condition.

The following valve positions would apply during idle

times:

VALVE POSITION

V1 CLOSED

V2 OPEN

V3 OPEN

V4 CLOSED

V5 OPEN

V6 CLOSED

V7 OPEN

11.3 Moisture Stabilization — At least four hours prior

to the start of a test, a constant flow of wet nitrogen

(100 ppm H

O) should be established through the

sampling port so as to maintain a steady moisture

output from the moisture generator. This is

accomplished by opening valve V7. During this time,

V4 is closed.

11.4 Moisture Level Verification — Once the moisture

level is stabilized in Section 11.2, the moisture value