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SEMI E67-0304 © SEMI 1997, 2004 6 Figure 3 Typical Performance Me asure vs. Number of Cycles 16.2 Record time to failure and plot failure times on lognormal or Weibull probability scal es (see Figure 4). This plot gives …
SEMI E67-0304 © SEMI 1997, 2004 5
Figure 2
Types of Cycles
14.4 Discontinue cycling. Perform the parametric tests
on all MFCs and record the results on the data sheet. If
any MFC experiences a soft failure, record the data but
do not stop the cycling procedure. However, if an MFC
experiences a hard failure, record the data, discontinue
testing this MFC, and take appropriate action to
maintain system integrity.
NOTE 2: The test does not require mention of the cause for
hard failure, as it is beyond the scope of this document.
14.5 The parametric tests should be performed in the
following order: particle, accuracy, response, and leak.
14.6 Perform all of the parametric tests on a single
MFC before proceeding to the next one. Record the
order of the MFCs tested and the time since the test
stand was idled.
14.7 If the readpoint is reached during a time when it is
not possible to start the parametric testing, continue
cycling until it is possible to begin. Record the number
of cycles that occurred before beginning testing.
14.8 Average the particle count information over a 10-
minute interval. Count particles for six 10-minute
intervals. Record the data from only the last three 10-
minute intervals.
14.9 Repeat Sections 14.4 through 14.8 until all the
readpoints have been completed or until all MFCs have
experienced hard failures.
15 Data Analysis
15.1 Calculations — See Appendix 1 for a discussion
on reliability calculation.
15.2 Interpretation of Results — The readpoints
included in Table 1 are approximately equidistant on a
log scale, and as data is collected, the number of
readpoints needed to show trends and estimate life will
decrease significantly.
16 Data Presentation
16.1 Plot each performance measure over number of
cycles to look for trends and shifts as a function of use
(see Figure 3). This gives a picture of dynamic
performance vs. use.
SEMI E67-0304 © SEMI 1997, 2004 6
Figure 3
Typical Performance Measure vs. Number of Cycles
16.2 Record time to failure and plot failure times on lognormal or Weibull probability scales (see Figure 4). This
plot gives an estimate of the useful life of an MFC (see Sections A1-1.1.4 – A1-1.1.5). Record data for the parameter
tested in the data sheet given within the parametric test method.
Figure 4
Time to Fail vs. Failure Percentage
SEMI E67-0304 © SEMI 1997, 2004 7
16.3 Record data for the parameter tested in the data
sheet given within the parametric test method.
16.4 The following test conditions are to be reported in
the data presentation:
16.4.1 date and time of test
16.4.2 operator
16.4.3 test flow rate (SLM)
16.4.4 test pressure (kPa)
16.4.5 ambient temperature (° C)
16.4.6 MFC orientation
16.4.7 MFC location in test bed
16.4.8 cleanroom or environment classification
16.4.9 MFC type, manufacturer, serial number, lot
number, and model number
16.4.10 LPC/CNC manufacturer, serial number,
sample flow rate (SLM), model number, calibration
date, particle range, and efficiency
16.4.11 test gas type and dew point (° C)
16.4.12 a schematic of the test apparatus, including
manufacturers and model numbers of all test apparatus
components
16.4.13 calibration dates for the flow meters
16.4.14 cycle time used for test
17 Precision and Bias
17.1 Precision and bias in this test are a function of the
uncertainty of the measurement equipment used. The
tester or end user is responsible for determining the
precision and bias of a particular setup and test.