semi合集-English.pdf - 第4755页

SEMI C6.7-93 © SEMI 1993, 2002 3 7 Report The report shall contain the value of the m easured sample volum es, values of all the variables defi ned in Section 3, the mass of the steel ball, and lengt h of the chain. Figu…

100%1 / 7923
SEMI C6.7-93 © SEMI 1993, 2002 2
3.2 Averaged Observed Concentration (XB, XM, XN)
B
X
= SUM(X
Bi
)/N
B
M
X = SUM(X
Mi
)/N
M
N
X = SUM(X
Ni
)/N
N
3.3 Calculate concentration (X
P
, X
Q
)
X
P
=
M
X –
B
X
X
Q
=
N
X –
B
X
3.4 Standard Deviation (S
B
, S
M
, S
N
)
S
B
= [SUM(X
Bi
–
B
X )
2
/N
B
– 1)]
1/2
S
M
= [SUM(X
Mi
–
M
X )2/(N
M
– 1)]
1/2
S
N
= [SUM(X
Ni
–
N
X )2/(N
N
– 1)]
1/2
3.5 Standard Error (SE
P
,SE
Q
)
SE
P
= [(S
M
2/N
M
) + (S
B
2/N
B
)]
1/2
SE
Q
= [(S
N
2/N
N
) + (S
B
2/N
B
)]
1/2
4 Apparatus
4.1 High-Pressure Particle Counter (HPC) — An
instrument capable of counting particles in compressed
gaseous nitrogen at a pressure up to 200 bar (3000 psi),
having a minimum counting efficiency of 50% at 0.2
µm and reaching 100% at 0.25 µm. This value is
determined at ambient pressure by the instrument
manufacturer using 0.2 µm monodisperse particles and
a reference counter with a proven counting efficiency of
100% at 0.2 µm. Note that the nominal flow rate of the
HPC is fixed at any pressure but the sample flow rate
should be adjusted to within 5% of the manufacturer’s
specified flow rate, for the pressure and reported its
equivalent standard flow rate at ambient pressure (1
bar).
4.2 Impact Shock Device — A device that can
reproducibly impart an impact shock of 10
4
m/sec
2
with
a 10% tolerance to a gas cylinder. A convenient set up
as shown in Figure 1 can be used. A steel ball is
attached to a chain with the other end fastened to the
test cylinder. The ball is lifted to form a 90° angle with
the cylinder, is released to follow a 90° free fall arc, and
strikes the test cylinder. The desired ball mass and
chain length are to be determined by monitoring the
corresponding shock intensity by an accelerometer. For
a typical 44 liter cylinder, a ball mass of 160 gm and a
chain length of 60 cm can produce the desired impact
shock.
5 Test Method
5.1 Determine the averaged background concentration
(
B
X ) by passing particle-free, compressed nitrogen
through the HPC. Count a minimum of 5 sample
intervals, each of at least 6 standard liters (0.2 SCF) or
taken over a time period of 6 minutes, whichever is
greater. A high purity gas filter can be used to remove
particles greater than 0.2 µm. Calculate
B
X as defined
in Section 3.
B
X must not exceed 1 particle per 30
second liters.
5.2 Set up the experimental apparatus as shown in
Figure 2. Directly connect the test cylinder to a High-
pressure Particle Counter (HPC), a pressure gauge, and
a Flow Control Device (FCD). Note that NO
REGULATOR is used before the HPC. The sampling
line should be clean and as short as possible. The flow
control device can be a metering valve and a flowmeter
or a critical orifice.
5.3 Determine
M
X by opening the cylinder valve and
count the particles for at least 5 sample intervals, each
of at least 6 standard liters (0.2 SCF) or taken over a
time of 6 minutes, whichever is greater. Calculate X
P
and SE
P
as defined in Section 3.
5.4 Apply 4 impact shocks of approximately 10
4
m/sec
2
each, 10 sec apart, to the bare surface of the test
cylinder. Each shock whould be applied at the
approximate vertical midpoint of the cylinder; the four
shocks should be separated from each other by
approximately 90° circumferentially.
5.5 Determine
N
X by counting the particles after the
shocks for at least 5 sample intervals, each of at least 6
standard liters (0.2 SCF) or taken over a time of 6
minutes, whichever is greater. The sampling should be
completed within 2 hours after the shocks. Calculate X
Q
and SE
Q
as defined in Section 3.
6 Specification
6.1 Maximum Permissible Particle Concentration —
10 particles per 30 standard liters.
6.2 The specification will be considered met if the
calculated concentration of particles plus two standard
errors does not exceed 10 particles per 30 standard
liters for both measurements before and after the impact
shocks, i.e.:
X
P
+ 2SE
P
≤ 10 particles/30 standard liters
and
X
Q
+ 2SE
Q
≤ 10 particles/30 standard liters
SEMI C6.7-93 © SEMI 1993, 2002 3
7 Report
The report shall contain the value of the measured
sample volumes, values of all the variables defined in
Section 3, the mass of the steel ball, and length of the
chain.
Figure 1
Figure 2
NOTICE: SEMI makes no warranties or
representations as to the suitability of the standards set
forth herein for any particular application. The
determination of the suitability of the standard is solely
the responsibility of the user. Users are cautioned to
refer to manufacturer’s instructions, product labels,
product data sheets, and other relevant literature
respecting any materials mentioned herein. These
standards are subject to change without notice.
The user’s attention is called to the possibility that
compliance with this standard may require use of
copyrighted material or of an invention covered by
patent rights. By publication of this standard, SEMI
takes no position respecting the validity of any patent
rights or copyrights asserted in connection with any
item mentioned in this standard. Users of this standard
are expressly advised that determination of any such
patent rights or copyrights, and the risk of infringement
of such rights, are entirely their own responsibility.
Copyright by SEMI® (Semiconductor Equipment and Materials
International), 3081 Zanker Road, San Jose, CA 95134. Reproduction o
f
the contents in whole or in part is forbidden without express written
consent of SEMI.
SEMI C6.2-93 © SEMI 1989, 2002 1
SEMI C6.2-93 (Reapproved 1102)
PARTICLE SPECIFICATION FOR GRADE 20/0.02 OXYGEN
DELIVERED AS PIPELINE GAS
This specification was technically approved by the Global Gases Committee and is the direct responsibility of
the North American Gases Committee. Current edition approved by the North American Regional Standards
Committee on July 21, 2002. Initially available at www.semi.org October 2002; to be published November
2002. Originally published in 1989; previously published in 1993.
1 Purpose
1.1 The purposes of this document are: (1) to set a
maximum permissible particle concentration for
20/0.02 grade oxygen bulk supply gas, and (2) to
describe a reference method for its verification.
2 Scope
2.1 This document applies only to oxygen gas
delivered through pipelines; it is not applicable to
cylinder gas or oxygen gas in its liquid state.
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 Terminology
3.1 Variables
V
Mi
= Volume of the i
th
sample interval of the pipeline
gas
V
Bi
= Volume of the i
th
sample interval of the
background
X
Mi
= Concentration of particles observed in the i
th
sample interval of the pipeline gas
X
Bi
= Concentration of particles observed in the i
th
sample interval of the background
N
M
= Number of sample intervals of the pipeline gas
N
B
= Number of sample intervals of the background
M
X =
Average observed concentration of counts in
the pipeline gas sample
B
X=
Average observed concentration of
backgroundcounts
C
X =
Calculated concentration of particles in the
pipeline gas
S
M
=
Standard deviation of
M
X
S
B
=
Standard deviation of
B
X
SE
C
=
Standard error of
C
X
3.2 Gas Sample Volume (V
Mi
, V
Bi
) — The volume of
the sample interval, expressed in standard liters at
standard conditions, 0°C (32°F) and 1.00 atmosphere
pressure. Standard Cubic Feet (SCF) is defined at
21.1°C (70°F) and 1.00 atmosphere pressure.
3.3 Average Observed Concentration of Counts
(
M
X ,
B
X ) — The average concentration of counts, i.e.:
X
M
=
X
Mi
∑
N
M
X
B
=
X
Bi
∑
N
B
3.4 Calculated Concentration of Particles (
C
X ) —
The concentration of particles in the pipeline gas
obtained by correcting the observed concentration in
the pipeline gas for the observed concentration in the
background, i.e.:
X
C
=
X
M
-
X
B
3.5 Standard Deviation (S
M
, S
B
, S
C
) — A statistical
measure of the spread of the concentration of the counts
or particles. The first two are obtained from the interval
and average concentrations and the number of intervals,
i.e.:
S
M
=
X
Mi
– X
M
(
)
2
∑
N
M
– 1
()
S
B
=
X
Bi
– X
B
()
2
∑
N
B
– 1
()
The third is obtained from the first two, i.e.:
S
C
= S
M
2
+ S
B
2
(
)
1
2
NOTE 1: These expressions are derived from an assumption
of a Gaussian (Normal) distribution.
3.6 Standard Deviation (S
M
, S
B
) — A statistical
measure of the spread of the concentration of the counts
or particles. The first two are obtained from the interval
and average concentrations and the number of intervals,
i.e.:
S
M
=
X
Mi
– X
M
(
)
2
∑
N
M
– 1
()
S
B
=
X
Bi
– X
B
()
2
∑
N
B
– 1
()
NOTE 2: These expressions are derived from an assumption
of a Gaussian (Normal) distribution.