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SEMI F62-0701 © SEMI 2001 1 SEMI F62-0701 TEST METHOD FOR DETERMINING M A SS FLOW CONTROLLER PERFORMANCE CHARACTERISITI CS FROM AMBIENT AND GAS TEMPER A TURE EFFECTS This spe cification was te chnically approve d by the …

SEMI F61-0301 © SEMI 20015

Feed

Water

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Figure 1

Schematic of a Typical Ultrapure Water System

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SEMI F62-0701 © SEMI 20011

SEMI F62-0701

TEST METHOD FOR DETERMINING MASS FLOW CONTROLLER

PERFORMANCE CHARACTERISITICS FROM AMBIENT AND GAS

TEMPERATURE EFFECTS

This specification was technically approved by the Global Facilities Committee and is the direct

responsibility of the North American Facilities Committee. Current edition approved by the North American

Facilities Committee on March 22, 2001. Initially available at www.semi.org May 2001; to be published July

2001.

1 Purpose

1.1 The purpose of this document is to define a

method for testing MFCs being considered for

installation into a gas distribution system and to

quantify ambient and gas temperature effects on the

MFC's indicated and actual flow.

2 Scope

2.1 This test method applies to metal and polymer

sealed MFCs with flow rates up to 30 slpm. The tests

include those listed below and are to be performed in

the following order:

1. Ambient Temperature Effects (Steady State and

Transient)

2. Gas Temperature Effects (Steady State and

Transient)

2.2 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 health practices and determine the

applicability or regulatory limitations prior to use.

3 Limitations

3.1 This method evaluates mass flow controllers in

typically encountered, realistic operating conditions.

3.2 This test method does not address operational

influences outside of the manufacturer's published

limitations.

4 Referenced Standards

4.1 None.

5 Terminology

5.1 Acronyms and Abbreviations

5.1.1 DUT — device under test

5.1.2 g — gravity

5.1.3 kPa — kiloPascal

5.1.4 MFC — mass flow controller

5.1.5 NIST — National Institute of Standard Tech-

nologies

5.1.6 sccm — standard cubic centimeters per minute

5.1.7 slpm — standard liters per minute

5.2 Definitions

5.2.1 stability, long term — reading ± 2% for over one

hour.

5.2.2 stability, short term — reading ± 2% within five

minutes.

5.2.3 zero setpoint — manufacturer's setpoint for no

flow from the MFC.

5.3 Descriptions of Terms

5.3.1 MFC

— inlet mass flow controller.

5.3.2 T

— the temperature in the environmental

control chamber.

5.3.3 T

— gas temperature at the inlet to the DUT.

5.3.4 T

max

— maximum manufacturer-rated temper-

ature for an MFC.

5.3.5 T

min

— 20°C or manufacturer rated minimum

temperature, whichever is greater.

5.3.6 TC

— temperature coefficient due to changing

gas temperature of DUT.

5.3.7 TC

— temperature coefficient due to changing

environmental temperature of DUT.

5.3.8 Q

— for the purpose of this method, the output

value of the flow standard in units of mass flow.

5.3.9 Q

ind

— for the purpose of this method, the output

value of the device under test in units of mass flow.

5.3.10 Q

— for the purpose of this method, the

intended output in mass flow units for a particular

setpoint.

5.3.11 V

— valve A

5.3.12 V

— valve B

5.3.13 V

I i

— inlet isolation valve

SEMI F62-0701 © SEMI 2001 2

5.3.14 V

— outlet isolation valve

6 Significance and Use

6.1 This test method defines a procedure for testing

components being considered for installation in a gas

distribution system. Application of this method is

expected to yield data allowing an end user to choose

among components tested for the purpose of

qualification for this installation.

7 Apparatus

7.1 See Figures 1a and 1b for schematics of the set-

ups.

7.2 Flow Measurement Device, National Institute of

Standard Technologies (NIST) traceable and capable of

measuring steady-state and transient flow

characteristics, preferably with differential pressure

sensors across a flow restriction. This device should

have a relative accuracy of at least 2 to 1 with respect to

the DUT.

7.3 Temperature Measurement Device, to measure test

gas temperature, NIST traceable and capable of real-

time measurement, with a low mass (< 0.05 g) sensor

and with low thermal losses through the leads (< 0.3

mW/°C).

7.4 Pressure Measurement Device, to measure test gas

pressure, NIST traceable, and capable of real-time

measurement to measure test gas pressure.

7.5 Gas Pressure Control Regulators, to maintain test

gas pressure at 275 kPa ± 5 kPa.

7.6 Gas Temperature Control, heat exchangers and

heaters to maintain the gas temperature equal to the test

temperature within ± 1 °C at the test flow rates.

7.7 Environmental Chamber, capable of stable

temperature control (± 1°C) from at least T

min

to a point

exceeding the maximum rated MFC temperature by

10°C.

8 Reagents and Materials

8.1 Test Gas, clean, dry nitrogen.

8.2 Tubing, cleaned and maintained to have no adverse

effects on the test.

8.3 Valves, capable of unimpaired operation at 100°C.

9 Safety Precautions

9.1 All manufacturers’ recommendations should be

followed and noted when testing the unit. Any safety

precautions should always be followed.

9.2 This standard does not purport to address all of the

safety problems, if any associated with its use. It is the

responsibility of the user to establish appropriate safety

and health practices and to determine the applicability

of regulatory limitations before using this method.

10 Technical Precautions

10.1 The flow standard may read a non-zero value due

to heating of the gas in the test to determine transient

effects on the zero. These readings should be noted.

11 Preparation of Apparatus

11.1 Setup and Schematic, (see Figure 1a) Ambient

Temperature Effects

11.1.1 Install an ambient temperature sensing device

within 5–10 centimeters horizontally adjacent to the

MFC body. The probe should not be in contact with the

MFC body or the environmental chamber walls.

11.1.2 Position the gas temperature sensor in the

center of the gas stream no more than 10 cm upstream

from the inlet surface of the MFC body.

11.1.3 After installation of the MFC, flow nitrogen at

a 100% setpoint to purge the system for a sufficient

time to remove atmospheric contamination.

11.1.4 If the MFC has a selectable Auto Zero function,

note this on all data presentation documents before

proceeding with the test.

11.1.5 Minimize the length of tubing between the

heater and the device under test to reduce gas

temperature changes.

11.2 Setup and Schematic, (see Figure 1b) Gas

Temperature Effects

11.2.1 Install a base temperature sensing device, T

adjacent to the MFC body. The probe should be in

contact with the MFC body.

11.2.2 Install an ambient temperature sensing device