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SEMI F70-0302 © SEMI 2002 4 9 Procedu re 9.1 A typical gas delivery system config uratio n is show n in Figure 4. T he follow ing test procedure shall be interpreted to apply to the actual test sy stem and recorded by th…

SEMI F70-0302 © SEMI 2002

8 Preparation of Apparatus

8.1 Set up apparatus and the gas supply system as shown in Figure 1.

RG F

By-pass

MFM

System

Under

Test

Particle

Counter

Sampler

MFC

VENT

Legend, V: Valve MFC: Mass Flow Controller MFM: Mass Flow Meter

F: Filter RG: Regulator NV: Needle Valve

Figure 1

Test Set Up Basic Flow Diagram

8.2 If the test flow rate is equal to or less than the sample flow rate required by the particle counter, insert a filter in

place of the sampler to fulfill the sample flow rate. (See Figure 2.)

Test

Flow

Particle

Counter

Filter

Test Flow Rate

≤

Sample Flow Rate

Figure 2

Full Sampling

8.3 If the test flow rate is higher than the sample flow rate required by the particle counter, use the sampler for

partial sampling. (See Figure 3.) To establish the test flow rate and obtain an isokinetic condition, it is required to

adjust the MFC in the test set up and the NV on the by-pass line. The by-pass line is required to have a capability to

handle the maximum test flow when the valves in the system under test is closed position during the pulse test.

Sampler

Particle

Counter

Test

Flow

Vent

FNV

By-pass

Test Flow Rate

Sample Flow Rate

Figure 3

Partial Sampling

SEMI F70-0302 © SEMI 2002

9 Procedure

9.1 A typical gas delivery system configuration is shown in Figure 4. The following test procedure shall be

interpreted to apply to the actual test system and recorded by the operator.

V2 V4 V6

V1 V3 V5

F2 F3

MFC1 MFC2 MFC3

LINE1 LINE2 LINE3

LEGEND

V1 - 6 Valves

F1 - 3 Filters

MFC1 -3 Mass Flow

Controllers

System Under Test

Figure 4

Typical Gas Delivery System Configuration

9.2 Determination of Background Counts

9.2.1 For test set up, insert a spool piece in place of the

system under test (i.e. the gas delivery system) as in

Figure 1.

9.2.2 Establish the test flow rate as 1.5 times of the

design flow rate and supply N

(or Ar). In this case the

design flow rate is determined as the flow rate of the

line which has maximum flow rate in the system under

test. Purge the test set up for more than 10 minutes.

9.2.3 Confirm the particle count is not more than 1

during 10 minutes after the purge. If the total volume of

the test flow is less than 28.3 liters, extend the sampling

time until it achieves more than 28.3 liters. If the

particle count is more than 1, repeat Sections 9.2.2 and

9.2.3.

9.2.4 Replace the spool piece with the test system.

9.3 Static Flow Test

9.3.1 Close all valves in the line 2 and 3, set the MFCs

as full scale or purge mode if available and fully open

the valves in the line 1.

9.3.2 Supply N

(or Ar) to the line 1 with 1.5 times of

the design flow rate of the line 1 and purge the test set

up for more than 10 minutes. In many case, this will

require the activation of the valve override on any

MFCs on the test line. It is also required to verify that

all components in the system can withstand 1.5 times

the design flow rate.

9.3.3 Count particles for more than 10 minutes. If the

total volume of the test flow is less than 28.3 liters,

extend the sampling time until it achieves more than

28.3 liters.

9.3.4 Repeat Sections 9.3.2 and 9.3.3 per all lines.

9.4 Pulse Flow Test

9.4.1 Close all valves in the line 2 and 3, set the MFCs

as full scale or purge mode if available and fully open

the valves in the line 1.

9.4.2 Supply N

(or Ar) to the line 1 with 1.5 times of

the design flow rate of the line 1 and purge the test set

up for more than 10 minutes.

9.4.3 Actuate V1 at the rate of 30 cycles/minute for 10

minutes if V1 is pneumatically operated valve. For

manually operated valve, actuate the valve at 4

cycles/minute for 10 minutes. Each cycle consists of on

and off actuation of the valve. The on and off cycles

should be of equal duration. If the total volume of the

test flow is less than 28.3 liters, extend the sampling

time until it achieves more than 28.3 liters. Count

particles during the period.

9.4.4 Repeat Section 9.4.3 for V2.

9.4.5 Repeat Sections 9.4.1 to 9.4.4 per all lines.

NOTE 2: For the pulse test, the total volume of the test flow

shall be half of the test flow rate multiplied by the sampling

time.

10 Calculation and Report

10.1 The following test conditions are to be included in

the test report:

• counter type (LPC or CNC)

• manufacturer of counter

• counter model (manufacturer’s model # or part #)

• sample flow

• particle diameter

• sampler diameter

• sample probe diameter

• test gas

• background count

• valve operation interval (for the pulse flow test)

• flow diagram of the system under test

10.2 Calculation of Data — The test result is reported

in number of particles in liters denoted by floating point

representation with two significant digits (ex. 2.3 × 10

/L). The method of calculation is shown in Section

10.2.1.

10.2.1 The following formula is used to calculate the

particles in a liter:

PARTICLES

where N: Total particle counts in 10 minutes or in the

extended period if the total volume of the test flow is

less than 28.3 liters.

V: Total sampling volume in liter in 10 minutes (mass

flow meter read value) or in the extended period if the

total volume of the test flow is less than 28.3 liters.

If the sample flow rate is equal to or more than the test

flow rate, V is equal to the total volume of the test flow

in liter in the sampling time.

If the sample flow rate is less than the test flow rate, V

is equal to the total volume of the sample flow in liter in

the sampling time.

10.3 Report Format — Sample report formats are

given in Appendixes 1 and 2.