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SEMI F64-0701 © SEMI 2001 4 13.4 The pn eumatic time cons ta nt f o r t he system shall be calculate d as shown bel o w: τ = (Volume × Pressure Dr op)/(P ressure × Volumetric Flow) where: • Volume is measured betw ee n t…

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SEMI F64-0701 © SEMI 20013
9.1.4 Dome-loaded pressure control, or other device
capable of producing specified pressure transients.
9.1.5 Flow standard, with time constant less than 20
msec and with full scale that is 200% of the DUT’s full
scale, accurate to 1% of full scale, linear to 0.5% of full
scale, and capable of resolving to 0.2% of full scale.
9.1.6 Data acquisition system measu res the electrical
signals from the device under test. The data acquisition
system may also read the signals from the flow
standard, record test data and control the test sequence.
9.2 Equipment Required for Method B
9.2.1 Inlet test gas filter.
9.2.2 Shutoff valve (qty 2).
9.2.3 Pressure transducer, available range 0–791 kPa
(0–100 psig), with measurement accuracy of ± 0.1%
and time constant less than 20 msec.
9.2.4 Two-stage pressure regulator, capable of 0–690
kPa (100 psia) control.
9.2.5 Flow standard, with full scale that is at least
120% of the DUT’s full scale, accurate to 1% of full
scale, linear to 0.5% of full scale, and capable of
resolving to 0.2% of full scale.
9.2.6 Data acquisition system measu res the electrical
signals from the device under test. The data acquisition
system may also read the signals from the flow
standard, record test data and control the test sequence.
9.3 Equipment Required for Method C
9.3.1 Inlet test gas filter.
9.3.2 Manual metering valve.
9.3.3 Pressure transducer, available range 0–446 kPa
(0–50 psig), with measurement accuracy of ± 0.2% and
time constant less than 20 msec.
9.3.4 Pressure transducer, 0–101.325 kPa ± 1% and
with time constant less than 20 msec (qty 1).
9.3.5 Shutoff valves (qty 2).
9.3.6 Isolation valve (qty 1).
9.3.7 Vacuum pump, with pumping speed of at least
30 lpm, with throttling and isolation valve.
9.3.8 Flow standard, with time constant less than 20
msec and with full scale that is 200% of DUT full scale
accurate to 1% of full scale, linear to 0.5% of full scale,
and capable of resolving to 0.2% of full scale.
9.3.9 Data acquisition system measu res the electrical
signals from the device under test. The data acquisition
system may also read the signals from the flow
standard, record test data and control the test sequence.
9.4 Equipment Required for method D
9.4.1 Pressure transducer, available range 0–446 kPa
(0–50 psig), with measurement accuracy of ± 0.2% and
time constant less than 20 msec. (2)
9.4.2 Flow standard, with time constant less than 20
msec and with full scale that is 200% of DUT full scale
accurate to 1% of full scale, linear to 0.5% of full scale,
and capable of resolving to 0.2% of full scale.
9.4.3 Isolation valve (qty 1).
9.4.4 Data acquisition system measu res the electrical
signals from the device under test. The data acquisition
system may also read the signals from the flow
standard, record test data and control the test sequence.
9.4.5 MFC with time constant less th an 20 msec and a
full scale flow rate that is 10 times the full scale flow
rate of the DUT.
10 Materials
10.1 Clean, dry nitrogen, with a dew point less than or
equal to -40°C, at a delivery pressure of 791 kPa (100
psig).
11 Safety Precautions
11.1 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 to determine the applicability of regulatory
limitations before using this method.
12 Test Specimen
12.1 Allow all components in the te st apparatus to
warm up following the manufacturer’s specification.
12.2 Take necessary steps when switching gases to
ensure that only the desired gas is in the DUT and flow
standard at the time the test is performed.
13 Preparation of Apparatus
13.1 Setup and Schematic — See Figures 1, 2, and 10.
13.2 Plumbing Design Requirements for Methods A
and C
13.3 The test system must be highly conductive and
must have no changes in direction closer than 20 tubing
diameters upstream of the DUT.
SEMI F64-0701 © SEMI 2001 4
13.4 The pneumatic time constant for the system shall
be calculated as shown below:
τ = (Volume × Pressure Drop)/(Pressure × Volumetric
Flow)
where:
• Volume is measured between the flow standard and
the DUT
• Pressure drop is across the flow standard
• Pressure is the pressure in the defined volume
• Volumetric flow is as measured by the standard
13.5 The pneumatic time constant a dded to the flow
standard time constant should ideally be less than 100
msec and should be recorded if larger. For method C,
the volume between MV and V
ip
should be kept to a
minimum.
13.6 The system must be relatively leak free, i.e., the
maximum inboard leak rate should be 2 × 10
-7
atm cc/s
He.
13.7 The system must be supported and isolated in a
manner that keeps it from vibration, shock, and other
conditions that could influence the results of this test.
14 Procedure
14.1 Inlet Transient Pressure Effects (Method A-1)
14.1.1 Assemble the test MFC into th e test apparatus.
(See Figure 1.)
14.1.2 Satisfy the manufacturer’s war m-up
requirements for the MFC.
14.1.3 Set the inlet pressure (P
1
) to 274 kPa (25 psig).
14.1.4 Give the DUT a 50% set-point (Q
SP
= ½Q
FS
)
and wait for Q
I
to reach stability.
14.1.5 Adjust the pressure control device to initiate a
step in P
1
to 287 kPa (27 psig) with a time constant of
one second (see Figure 3c).
14.1.6 Wait until Q
I
and Q
A
have reac hed stability.
14.1.7 Using the pressure control device, initiate a step
in P
1
to 274 kPa (25 psig) with a time constant of one
second.
14.1.8 Give the DUT a 100% set-poin t (Q
SP
= Q
FS
)
and wait for stability.
14.1.9 Repeat Sections 14.1.5 through 14.1.7.
14.2 Process Side Effects (Method A-2)
14.2.1 Assemble the test MFC into th e test apparatus
(see Figure 1).
14.2.2 Satisfy the manufacturer’s war m-up
requirements for the MFC.
14.2.3 Set the inlet pressure (P
1
) to 274 kPa (25 psig).
14.2.4 Give the DUT a 50% set point (Q
SP
= ½Q
FS
)
and wait for Q
I
to reach stability.
14.2.5 Using the pressure control dev ice, initiate a
ramp in P
1
to 356 kPa (37 psig) (see graph in Figure
4c). Use a ramp rate between 0.7 kPa (0.1 psi) per
second and 21.0 kPa (3psi) per second. Record the
ramp rate used on the data sheet.
14.2.6 Wait until Q
I
and Q
A
have reac hed stability.
14.2.7 Using the pressure control dev ice, initiate a
ramp as in 14.2.5, initiate a ramp in P
1
to 274 kPa (25
psig) (see graph in Figure 4c).
14.2.8 Repeat Sections 14.2.5 through 14.2.7.
14.3 Inlet Pressure Effects, Steady S tate (Method B)
14.3.1 Assemble the DUT in the test apparatus (see
Figure 1).
14.3.2 Satisfy the manufacturer's war m-up
requirements for the DUT.
14.3.3 Set the inlet pressure (P
1
) to 205 kPa (15 psig).
14.3.4 Close V
io
, open DUT control valve.
14.3.5 Wait until Q
R
and Q
A
have rea ched stability.
Record P
1
, Q
I
and Q
A
(see Table A3.1).
14.3.6 Open V
io
and give the DUT a 50% set-point.
(Q
SP
= ½Q
FS
).
14.3.7 Wait until Q
I
and Q
A
have reac hed stability.
Record P
1
, Q
I
and Q
A
(see Table A3.1).
14.3.8 Give the DUT a 100% set-point (Q
SP
= Q
FS
).
14.3.9 Wait until Q
I
and Q
A
have reac hed stability.
Record P
1
, Q
I
and Q
A
(see Table A3.1).
14.3.10 Set inlet pressure (P
1
) to 446 kPa (50 psig) and
repeat Sections 14.3.4 through 14.3.9.
14.4 Outlet Pressure, Step Change (Method C)
14.4.1 Assemble the test MFC into th e test apparatus.
(See Figure 1.)
14.4.2 Satisfy the manufacturer's war m-up
requirements for the MFC.
14.4.3 Set the inlet pressure (P
1
) to 274 kPa (25 psig)
(see Figure 9).
14.4.4 Give the DUT a 50% set point (Q
SP
= ½Q
FS
).
14.4.5 Throttle the pump rate until P2 = 26.664 kPa.
SEMI F64-0701 © SEMI 20015
14.4.6 Open V
io
and adjust the meteri ng valve, MV,
until P
2
= 101.325 kPa.
14.4.7 Allow Q
I
to reach stability. Re cord P
1
, Q
I
, and
Q
A
(see Table A3).
14.4.8 Close V
io
. P
2
should = 26.664 kPa.
14.4.9 Allow Q
I
to reach stability. Re cord P
1
, Q
I
, and
Q
A
(see Table A3).
14.4.10 Give the DUT a 100% set point and repeat
Sections 14.4.5 through 14.4.9.
14.5 Crosstalk Pressure Effect (Me thod D)
14.5.1 Assemble the DUT in the test apparatus (see
Figure 10).
14.5.2 Satisfy the manufacturer’s war m-up
requirements for the DUT.
14.5.3 Set the inlet pressure (P
1
) to 274 kPa (25 psig)
14.5.4 Give the DUT a 100% set point (Q
SP
= Q
FS
).
14.5.5 Give the 10× MFC a 100% set point (Q
SP
=
Q
FS
).
14.5.6 Wait until the DUT and MFC achieve stability.
14.5.7 Record P
1
, P
2
, the indicated flo w from the
DUT, the indicated flow from the MFC and the
indicated flow from the flow standard continuously
with the data acquisition system.
14.5.8 While monitoring command the 10 × MFC to a
zero set-point. Wait until the DUT becomes stable then
command the 10× MFC to a 100% set Point.
14.5.9 Sample Plot is shown in Figur e 11.
15 Calculations or Interpreta tion of Results
15.1 See Appendix 1 for detailed information on data
collection and interpretation for Methods A-1, A-2, B,
and C.
15.2 Calculations — The indicated MFC flow output
data and the flow standard output data should be
converted to percent of full scale flow as follows:
100 x
(v)output scale full
(v) dataoutput
= flow scale full of %
(1)
15.3 Interpretation — Collect the following data and
report as an effect of transient pressure conditions:
15.4 Plot of indicated flow, actual flow, and flow set
point versus time.
15.5 Duration of instability. Maximum and minimum
deviations from the steady state actual and indicated
flows. Calculate the positive and negative integrals,
along with the total integral of variations in the actual
and indicated flows.
15.6 Inlet (P
1
) and outlet (P
2
) values.
15.7 The number of repetitions required to achieve a
confidence factor of 95% for each test step.
15.8 Data plots for the measured va lues must be
generated and presented in a manner similar to that
shown in Figures 3, 4, and 5 and in Table 1.
16 Related Documents
16.1 Military Standards
1
MIL-STD 45662 Calibration Systems Requirements
1 Naval Publication and Forms Center, 5801 Tabor Avenue,
Philadelphia PA 19120 U.S.A