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SEMI F55-0600 © SEMI 2000 4 NOTE 6: Data throughout this test m ay be recorde d in a forma t si mila r to that foun d in Table A 1.1. 13.6 Open valve V1 and flow dry N 2 a t a setpoint of 80% ± 5% of the DUT FS an d wait…

SEMI F55-0600 © SEMI 20003

10.2 Become familiar with the safe handling practices

associated with the corrosive gas before undertaking

this test.

11 Preparation of Apparatus

11.1 The test apparatus is the source of three gases—

dry N

, dry HCl, and N

containing a known level of

water vapor. Each gas can be valved through the DUT

individually with minimal cross contamination. The

DUT actively controls the gas flow in each case. The

gas then flows into either a scrubbed exhaust system for

safe disposal or a reclamation system. A reference

flowmeter in the dry N

supply line is used to detect

changes in calibration of the DUT when dry N

flowing in series through both devices.

11.2 Setup and Schematic — See Figure 1 for a

schematic of the test apparatus. This schematic may

not show in detail all the components required in an

actual system.

11.3 Supply the manufacturer's reco mmended power

to the DUT. Provide MFC setpoint and purge

command (if available). Monitor the following:

11.3.1 DUT setpoint input.

11.3.2 DUT indicated flow output.

11.3.3 DUT valve drive output (if available)

11.3.4 actual flow (output of reference flowmeter)

11.4 Verify that the proper moisture levels exist in

each of the test gases.

11.5 Provide a purge flow loop that maintains a

constant flow of dry N

in the line from the DUT to the

exhaust system. Flow in this loop must be sufficient to

prevent back diffusion into the DUT of moisture

generated in the exhaust system, particularly when flow

into the DUT is shut off for measuring zero.

11.6 If the moisture generator is sup plied from the

same N

source that supplies the dry N

, take

precautions to avoid the diffusion of moisture from the

moisture generator into the dry N

line. Such

precautions may include the use of separate pressure

regulators and other valving.

11.7 Moisture generators typically take time to

stabilize. A continuous flow should be maintained

through the moisture generator during the test to

maintain a stable moisture flow. This may require

diverting the output flow to a vent when not flowing

through the DUT.

11.8 Periodically verify the moisture concentration of

wet N

with a suitable moisture analyzer.

11.9 Follow manufacturer set-up procedures for all

equipment.

11.10 Conduct the test at an ambient temperature of 22

± 2°C.

11.11 The DUT moisture generator, flowmeters, and

other instrumentation should have been stabilized at

room temperature for 24 hours before beginning the

tests. It is not necessary to flow gas during this

stabilization time.

11.12 All portions of the plumbing system that could

contain HCl must be helium leak tested per SEMI F1

before introducing HCl into the system. When

changing the DUT or other components, at least those

portions of the system that were changed must be re-

tested.

NOTE 4: Small leaks in a corrosive gas system can become

much larger without warning.

12 Calibration and Standardization

12.1 Calibrate all instrumentation using current

standards that are traceable to an appropriate standards

laboratory. In the absence of appropriate standards, use

manufacturer recommendations for calibration.

13 Procedure

NOTE 5: Refer to Figure 2 for a flowchart of the following

test.

13.1 Set the pressure of each of the HCl and Dry N

gas sources at 140 kPa ± 5%. Set the pressure of the

N2 to the moisture generator to the appropriate value

recommended by the manufacturer. If the test must be

run at some other pressure, because of a limitation of

the DUT, report this fact in the test results.

13.2 Start the wet N

flow to vent or through the

moisture analyzer. Establish a stable moisture

concentration at 100 ppmv ± 20% before beginning the

test sequence. Set the wet N

to flow within ± 5% of

the DUT flow that will be run during the test.

13.3 Place the DUT control valve in the purge or fully

open position by supplying a purge command or a

200% setpoint. Purge with dry N

at a rate of one to

two times FS flow for one hour to establish initial

conditions. The purge rate is controlled by adjusting

the supply pressure and is monitored by a purge-rate

flowmeter located in the gas-supply path. Follow the

manufacturer's procedure for fully opening the DUT

control valve.

13.4 Provide a setpoint to the DUT for 80 ± 5% of FS

flow.

13.5 Determining the Test Baseline and Measurement

Repeatability.

SEMI F55-0600 © SEMI 2000 4

NOTE 6: Data throughout this test may be recorded in a

format similar to that found in Table A1.1.

13.6 Open valve V1 and flow dry N

at a setpoint of

80% ± 5% of the DUT FS and wait 10 minutes.

13.7 Record:

13.7.1 DUT setpoint

13.7.2 DUT indicated flow

13.7.3 DUT valve drive output (if available)

13.7.4 Actual flow

13.8 Stop flow by closing V1. Drive the MFC control

valve to a closed position by providing a zero setpoint

or as otherwise provided by the manufacturer. Allow

the MFC indicated flow output to stabilize for a

minimum of three minutes.

13.9 Record the DUT indicated flow and the actual

flow during the zero flow condition.

13.10 Repeat Sections 13.6 through 13.9 twelve times.

This will yield 12 data points for each of the six

measured parameters.

13.11 For each of the six parameters recorded,

perform the following calculation on the 12 baseline

data points to determine the repeatability of the

measurement:

(highest value - lowest value) × 100

average of the 12 values

13.12 If each of the six parameters is not repeatable

within 0.2% during these two hours, subsequent test

data may not be valid and the problem should be

resolved before proceeding with the test.

13.13 Baseline

NOTE 7: Use the averaged value of the measurements made

in Section 13.13 for each parameter as the baseline for that

parameter in the following tests.

13.14 Test Sequence — Without changing the DUT

setpoint, repeat the test sequence in Sections 13.19-

13.22 every 30 minutes, continuously, 24 hours per day,

seven days per week until one of the following test

termination conditions is met.

13.15 The test should not be interrupted because the

DUT may continue to corrode during the interruption,

making test results non-repeatable. The output of the

moisture generator should be measured periodically

during the test sequence to ensure that it remains within

the test specifications.

13.16 Terminate the test sequence if:

13.16.1 The DUT fails to function

13.16.2 The actual-flow shift from baseline exceeds

25%

13.16.3 The valve drive exceeds the manufacturer's

limits

13.16.4 The DUT indicated flow differs from

commanded setpoint by > 5%

13.16.5 The test exceeds 5000 cycles

13.17 Flow dry N

for five minutes. After five

minutes, record data on the six test parameters as done

in Section 13.7, interrupting flow to record the DUT

indicated flow and reference flowmeter output at zero

flow. After taking measurements, flow dry N

again so

that the total length of this step is 10 minutes. Record

data as shown in Figure 3.

13.18 Flow dry HCl for seven minutes.

13.19 Repeat Section 13.19 and then proceed to

Section 13.22.

13.20 Flow wet N

for three minutes. If no test

termination condition is met as described in Section

13.18, repeat Sections 13.19 - 13.22. If a test

termination condition is met, proceed to Section 13.23.

13.21 After the test has been completed, place the

DUT control valve in the purge or fully open position.

Purge with dry N

for one hour or at least 50 volume

changes. Cycle the purge gas for 15 seconds on and 15

seconds off by opening and closing V1 for the duration

of the purge. Follow the manufacturer's procedure for

fully opening the DUT control valve.

NOTE 8: Verify purge flow with the reference flowmeter or

by using other means. Corrosion may have rendered the

control valve inoperable. An alternate approach for purging

any corrosive material from the system may have to be

followed.

13.22 Alternate Approach to Purging.

13.23 If gas cannot be purged through the DUT, cycle-

purge each end of the DUT separately using Sections

13.26 through 13.28.

13.24 With valves V2 and V3 closed for the duration

of the procedure, close valve V6 and pressurize both

sides of the system by opening V1 and V7 for 15

seconds.

13.25 Vent pressure through the exhaust system by

closing V1 and opening V6 for 15 seconds.

13.26 Repeat pressure and vent cycles for a minimum

of one hour.

13.27 Remove the DUT. Preserve the test system, if

desired, by taking steps to exclude atmospheric

moisture. Such steps could include capping the system

and shutting all valves. Alternately, the DUT may be

replaced with a spool piece. The system can then be

continuously purged with dry N

NOTE 9: The DUT will be contaminated with corrosive

material. See Precautions in Section 10. Preserve the DUT

for failure analysis, if desired.

14 Calculations or Interpretation of Results

14.1 Report data in a tabular format and graph per

Appendix 1. Any parameter which changes more than

1% from its baseline should also be graphed. Note the

reason the test was terminated. Test results may be

summarized in a single parameter by reporting the

number of test cycles to reach a 2% shift in actual flow

or to reach DUT failure, whichever occurs first. In this

test, more data is reported than is required to calculate

the gross test result. The extra data is used when

analyzing test results to determine the cause of failure.

Further explanation of the significance of the data is

beyond the scope of this test method.

15 Data Analysis.

15.1 Calculate any parameter-shift in percent as

follows:

(baseline value - current value) × 100

baseline value

16 Reporting Results

16.1 Report the number of test cycles to reach a 2%

shift in actual flow or to reach DUT failure, whichever

occurs first.

17 Precision and Accuracy

17.1 This method is limited in its precision by the

calibration of the measurement devices, the temperature

of the apparatus, and the concentration of water vapor

in N

. Sources of bias are unknown at this time, but

they probably include peculiarities in the construction

of the apparatus.

18 Related Documents

18.1 Material safety data sheet (MSDS) for hydrogen

chloride, which can be obtained from a supplier of the

gas.

19 Illustrations

Purge Rate

Flow Meter

MFM

Reference

Meter

DUT

Exhaust

System

Moisture

Generator

MFC

or Control

Valve

Vent

Moisture Level

Test Port

Purge Flow

Dry HCl in

Dry N

Figure 1

Schematic of Apparatus