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SEMI C3.22-1000 © SEMI 1983, 2004 1 SEMI C3.22-1000 (Withdrawn 1104) STANDARD FOR OXYGEN (O 2 ), 99.5% QUALITY This standard was technically approved b y the Global Gases Committee and is the direct r e sponsibility of t…

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SEMI C3.58-0303 © SEMI 2000, 2003 5
Figure 3
Determination of Organic Impurities in Octafluorocyclobutane
6.3.4.2 Obtain a continuous flow sample of the Octafluorocyclobutane source. The sample system by which the
octafluorocyclobutane is passed to the instrument should consist of electroplated stainless steel tubing, zero dead-
volume fittings, and be heated and purged with dry gas while not in use.
6.3.4.3 Allow the sample gas to flow through the sampling system and instrument until a stable reading is obtained.
NOTICE: SEMI makes no warranties or representations as to the suitability of the standard set forth herein for any
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Copyright by SEMI® (Semiconductor Equipment and Materials
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consent of SEMI.
SEMI C3.22-1000 © SEMI 1983, 2004 1
SEMI C3.22-1000 (Withdrawn 1104)
STANDARD FOR OXYGEN (O
2
), 99.5% QUALITY
This standard 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 11, 2004. Initially available at www.semi.org September 2004; to be published
November 2004. Originally published in 1983; previously published in 1993.
NOTICE: This document was balloted and approved
for withdrawal in 2004.
1 Description
1.1 Oxygen is a colorless, odorless and oxidizing gas.
It supports combustion.
2 Specifications
ASSAY: 99.5%
Impurities Maximum Acceptable
Level (ppm)*
Carbon monoxide and Carbon
dioxide (CO + CO
2
)
5
Nitrogen (N
2
) 100
Nitrous oxide (N
2
O) 2
Particles **
Total Hydrocarbons expressed as
Methane (THC)
25
Water (H
2
O) (v/v) 1
TOTAL IMPURITIES
INCLUDING RARE GASES
5,000
* An analysis of significant figures has not been considered. The
number of significant figures will be based on analytical accuracy and
the precision of the provided procedure.
** To be determined between supplier and user.
3 Physical Constants (for information only)
Metric Units US Units
Molecular weight 31.999 31.999
Boiling point at 1 atm -183°C -297.4°F
Density of gas at 25°C
(77°F) and 1 atm
1.309 kg/m
3
0.082 lb/ft
3
Specific gravity of gas at
21.1°C (70°F) and 1 atm
(air = 1)
1.1049 1.1049
Density of liquid at
boiling point
1142 kg/m
3
71.27 lb/ft
3
4 Analytical Procedures
4.1 Carbon Monoxide, Carbon Dioxide, and Nitrous
Oxide — This procedure is for the determination of
carbon monoxide, carbon dioxide and nitrous oxide in
oxygen using infrared spectrophotometry.
4.1.1 Detection Limits — 0.5 ppm (mole/mole) carbon
monoxide, 0.1 ppm (mole/mole) carbon dioxide, and
0.2 ppm (mole/mole) nitrous oxide.
4.1.2 Instrument Parameters
4.1.2.1 10 meter variable path infrared gas cell.
4.1.2.2 Grating infrared spectrophotometer.
4.1.2.3 Bourdon Vacuum Gauge.
4.1.3 Calibration Standards — 10 ppm (mole/mole)
carbon monoxide, 10 ppm (mole/mole) carbon dioxide
and 10 ppm (mole/mole) nitrous oxide, balance oxygen.
4.1.4 Operating Procedure
4.1.4.1 Pressurize the evacuated gas cell to 50 psia
with the calibration standard. Scan the following wave
numbers for absorbance: carbon monoxide 2172 cm
-1
,
nitrous oxide 2235 cm
-1
, and carbon dioxide 2360 cm
-1
.
4.1.4.2 Evacuate the cell and pressurize to 50 psia
with the oxygen sample. Scan the appropriate wave
numbers as in 4.1.4.1.
4.1.4.3 Compare the absorbance of the calibration
standard to that of the oxygen sample being tested.
Calculate the concentrations of carbon monoxide,
carbon dioxide and nitrous oxide, using the formula
below. The results may not exceed the specifications in
Section 2 of this Standard.
Sample Absorbance
Standard Absorbance
Concentration
of Standard
Concentration
of Sample
4.2 Nitrogen — This procedure is for the
determination of nitrogen in oxygen using a gas
chromatograph with a thermal conductivity detector.
4.2.1 Detection Limit — 10 ppm (mole/mole).
4.2.2 Instrument Parameters
4.2.2.1 Column: 5A molecular sieve, 4.6 m (15 ft) by
3.2 mm (1/8 in) ss or equivalent.
4.2.2.2 Carrier Flow: 30 mL/min helium.
4.2.2.3 Sample Volume: 2.0 mL.
SEMI C3.22-1000 © SEMI 1983, 2004 2
4.2.2.4 Temperatures:
Detector 200°C
Column Oven 21°C
4.2.3 Calibration Standard — 100 ppm (mole/mole)
nitrogen in oxygen.
4.2.4 Operating Procedure
4.2.4.1 Inject the calibration standard into the column
using a gas sampling valve. Record the retention time
and peak area.
4.2.4.2 Inject the sample to be tested in same manner
as the calibration standard. Record the retention time
and peak area.
4.2.4.3 Repeat 4.2.4.1.
4.2.4.4 Compare the average peak area of the
calibration standard to that of the oxygen sample being
tested. Calculate the concentration of nitrogen, using
the formula below. The result may not exceed the
specification in Section 2 of this Standard.
Sample Peak Area
Standard Peak Area
Concentration
of Standard
Concentration
of Sample
4.3 Total Hydrocarbons — This procedure is for the
determination of total hydrocarbons in oxygen using a
continuous flow flame ionization detector equipped
total hydrocarbon analyzer. (See Notes 1, 2, 3.)
4.3.1 Detection Limit — 0.1 ppm (mole/mole).
4.3.2 Flow Requirements
4.3.2.1 High purity, hydrocarbon-free (less than 1.0
ppm) hydrogen: 35–40 mL/min or 40% hydrogen in
either helium or nitrogen matrix at 75–80 mL/min.
4.3.2.2 Dry, hydrocarbon-free (less than 1.0 ppm) air:
350–400 mL/min.
4.3.2.3 Set sample flow rates in accordance with the
instrument manufacturer’s instructions.
4.3.3 Calibration Standards
4.3.3.1 Zero oxygen with known quantity of
hydrocarbons at 0.5 ppm level.
4.3.3.2 The upper level span gas not exceeding 4 times
the concentration of the specification.
4.3.4 Operating Procedure
4.3.4.1 Do not change the flow settings for hydrogen,
air, and sample once established.
4.3.4.2 Introduce the zero oxygen with known
quantity of hydrocarbons and, using the 0–10 ppm
range, set the needle (or output) to read the correct level
using the zero adjust knob.
4.3.4.3 Introduce the span gas standard in oxygen and,
using the span adjust knob, set the needle (or output
reading) to match the level of hydrocarbons in the span
gas.
4.3.4.4 Introduce oxygen sample into the analyzer and
read the quantity of hydrocarbons on the analyzer
meter. The result may not exceed the specification in
Section 2 of this Standard.
4.4 Water — This procedure is for the determination
of trace moisture (water) in oxygen using a continuous
flowing, cooled-surface condensation, dewpoint/frost-
point hygrometer. (See Notes 4, 5, 6.)
4.4.1 Detection Limit — 0.6 ppm (vol/vol) at -79°C (-
100°F).
4.4.2 Flow Requirements
4.4.2.1 Set sample flow rate and pressure in
accordance with the instrument manufacturer’s
instructions.
4.4.2.2 Gas must flow past the chilled mirror where
optic means are provided to detect the deposit (or frost)
and to read the thermometer measuring the temperature
of the mirror.
4.4.3 Calibration Standard — A calibration
thermometer designed to indicate temperatures in the
-79°C (-110°F) range is required.
4.4.4 Operating Procedure
4.4.4.1 Obtain a continuous flow of sample gas from
the source using a clean stainless steel sampling line
which has been purged dry after exposure to ambient
moisture.
4.4.4.2 After prepurging with a dry gas, allow the
sample gas to flow through the sampling system and the
dewpoint/frostpoint hygrometer for one hour to 24
hours to allow the entire system to reach equilibrium
with regard to moisture content.
4.4.4.3 After equilibrium has been reached, cool down
the mirror to determine the actual dewpoint/frostpoint
of the sample gas. Follow the manufacturer’s
recommendations to create the temperatures needed.
4.4.4.4 Continue to verify the dewpoint/frostpoint for
at least 30 minutes after a stable reading has been
confirmed.
4.4.4.5 Correct the dewpoint reading from the
measured pressure to 1 atm of pressure. The result may
not exceed the specification in Section 2 of this
Standard.