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SEMI C57-0305 © SEMI 2005 3 9.1.2.3 S ample Volume : 0.5 to 2.0 mL 9.1.2.4 Temperatures : Detector 280  C Column Oven 60  C Methanizer 350  C 9.1.3 Calibration S tandards — 1–5 ppm carbon m onoxide, 1–5 ppm carbon dio…

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SEMI C57-0305 © SEMI 2005 2
Table 1 Impurity and Other Requirements for Various Grades of Argon
Previous SEMI Reference #
C3.1-1101
(Specification)
C3.46-1102
(Specification)
C3.42-90
(Guideline)
Grade 4.8 5.2 6.0
Purity 99.998% 99.9992% 99.99990%
#1
Impurities Maximum Acceptable Level (ppm)
#2
Carbon monoxide and carbon dioxide
(CO + CO
2
)
0.5 0.5 N/A
Carbon Dioxide (CO
2
) N/A N/A 0.05
Carbon Monoxide (CO) N/A N/A 0.05
Hydrogen (H
2
) 1 1 0.10
Nitrogen (N
2
) 10 5 0.5
Oxygen (O
2
) 2 0.5 0.05
Total Hydrocarbons expressed as Methane
(THC)
0.5 0.5
0.1
Water (H
2
O) (v/v) 1 0.5 0.1
TOTAL SPECIFIED IMPURITIES 15 8 0.95
Particles
#3 #3 #3
#1
A purifier is allowed to be used to meet this specification.
#2
An analysis of significant figures has not been considered. The number of significant figures is based on analytical accuracy and the precision
of the provided procedure.
#3
To be determined between supplier and user.
8 Physical Constants
8.1 The physical constants of argon are given in Table 2 (for information only).
Table 2 Physical Constants of Argon (for information only)
Metric Units US Units
Molecular weight 39.948 39.948
Boiling point at 1 atm 185.9°C 302.6°F
Density of gas at 21.1°C (70°F)
and 1 atm
1.656 kg/m
3
0.1034 lb/ft
3
Specific gravity of gas at 21.1°C
and 1 atm (air = 1)
1.38 1.38
Density of liquid at boiling point 139 kg/m
3
8.698 lb/ft
3
9 Analytical Procedures for Grade 4.8 Argon
NOTE 1: Introduce the calibration standard as many times as necessary to achieve the desired precision.
NOTE 2: All gases used in the analysis of the sample should contain no more than 10% of the sample value of the component of
interest unless otherwise specified.
9.1 Carbon Monoxide and Carbon Dioxide — This procedure is for the determination of carbon monoxide and
carbon dioxide in argon using a gas chromatograph with a flame ionization detector and methanizer.
9.1.1 Detection Limit — 100 ppb
9.1.2 Instrument Parameters
9.1.2.1 Column: Porapak T or Q, 3 m (9.8 ft) by 3.2 mm (1/8 in) OD by 2.2 mm (0.085 in) ID stainless steel; or
Chromosorb 102, 2 m (6.6 ft) by 3.2 mm (1/8 in) OD by 2.2 mm (0.085 in) ID stainless steel; or equivalent.
9.1.2.2 Carrier Flow: 30 mL/min helium
SEMI C57-0305 © SEMI 2005 3
9.1.2.3 Sample Volume: 0.5 to 2.0 mL
9.1.2.4 Temperatures:
Detector
280C
Column Oven
60C
Methanizer
350C
9.1.3 Calibration Standards — 1–5 ppm carbon monoxide, 1–5 ppm carbon dioxide, balance argon.
9.1.4 Operating Procedure
9.1.4.1 Inject the calibration standard into the column using a gas sampling valve. Record the retention times and
peak areas. The order of elution is carbon monoxide, carbon dioxide.
9.1.4.2 Inject the sample to be tested in same manner as the calibration standard. Record the retention times and
peak areas.
9.1.4.3 Repeat ¶9.1.4.1.
9.1.4.4 Compare the average peak areas of the calibration standard to that of the argon sample being tested.
Calculate the concentrations of carbon monoxide and carbon dioxide, using the formula below.
9.1.4.5 The result may not exceed the specification in Table 1.
9.2 Hydrogen and Nitrogen — This procedure is for the determination of hydrogen and nitrogen in argon using a
gas chromatograph with a helium ionization detector.
9.2.1 Detection Limit — 0.5 ppm
9.2.2 Instrument Parameters
9.2.2.1 Column: 5A molecular sieve, 65.6 m (20 ft) by 3.2 mm (1/8 in) OD by 2.2 mm (0.085 in) ID stainless steel
or equivalent.
9.2.2.2 Carrier Flow: 30 mL/min helium.
9.2.2.3 Sample Volume: 1.0 to 3.0 mL
9.2.2.4 Temperatures:
Detector
125C
Column Oven
25C
9.2.3 Calibration Standard — 1–5 ppm hydrogen in argon, 10–30 ppm nitrogen in argon.
9.2.4 Operating Procedure
9.2.4.1 Inject the calibration standard into the column using a gas sampling valve. Record the retention times and
peak areas.
9.2.4.2 Inject the sample to be tested in same manner as the calibration standard. Record the retention times and
peak areas.
9.2.4.3 Repeat ¶9.2.4.1. (See Note 1.)
Sample Peak
Area
Standard Peak Area
Concentration
of standard
Concentration
of sample
SEMI C57-0305 © SEMI 2005 4
9.2.4.4 Compare the average peak area of the calibration standard to that of the argon sample being tested.
Calculate the concentration of hydrogen and nitrogen, using the formula below.
9.2.4.5 The result may not exceed the specifications in Table 1.
9.3 Oxygen — This procedure is for the determination of oxygen in argon using a continuous flow analyzer using
an electrochemical method.
9.3.1 Detection Limit — 100 ppb.
9.3.2 Flow Rate — Set sample flow rates in accordance with the instrument manufacturer’s instructions.
9.3.3 Calibration Standard — 3–15 ppm oxygen in argon or in accordance with the instrument manufacturer’s
instructions.
9.3.4 Operating Procedure
9.3.4.1 Do not change the initial sample flow setting once established.
9.3.4.2 Introduce argon sample and record oxygen reading. The result may not exceed the specification in Table 1.
9.4 Total Hydrocarbons — This procedure is for the determination of total hydrocarbons in argon using a
continuous flow flame ionization detector equipped total hydrocarbon analyzer.
NOTE 3: The 0–1 range can be used provided that zero and span gas standards in hydrogen with known levels of hydrocarbons
between 0 and 1 ppm are used in the calibration of the analyzer.
NOTE 4: As the flow rate and heat capacity of the matrix gas affect the instrument output, the zero gas matrices should be
coincided with that of the sample gas.
NOTE 5: The effective response of a flame ionization detector-equipped total hydrocarbon analyzer to different hydrocarbons
can vary and should be approximated. However, the response of the common hydrocarbon impurities in argon can be accurately
totaled and compared to methane.
9.4.1 Detection Limit — 0.1 ppm.
9.4.2 Flow Requirements
9.4.2.1 High purity, hydrocarbon-free (less than 0.1 ppm) hydrogen: 35–40 mL/min or 40% hydrogen in either
helium or nitrogen matrix at 75–80 mL/min.
9.4.2.2 Dry, hydrocarbon-free (less than 0.1 ppm) air: 350–400 mL/min.
9.4.2.3 Set sample flow rates in accordance with the instrument manufacturer’s instructions.
9.4.3 Calibration Standards
9.4.3.1 Zero argon with known quantity of hydrocarbons at 0.1 ppm level.
9.4.3.2 The upper level span gas not exceeding five times the concentration of the specification.
9.4.4 Operating Procedure
9.4.4.1 Do not change the initial flow settings for hydrogen, air and sample once established.
9.4.4.2 Introduce the zero argon 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.
9.4.4.3 Introduce the span gas standard in argon and using the span adjust knob, set the needle (or output reading)
to match the level of hydrocarbons in the span gas.
9.4.4.4 Introduce argon sample into the analyzer and read the quantity of hydrocarbons on the analyzer meter. The
result may not exceed the specification in Table 1.
9.5 Water — This procedure is for the determination of trace moisture (water) in argon using a continuous flowing
piezoelectric hygrometer.
Sample Peak
Area
Standard Peak Area
Concentration
of Standard
Concentration
of Sample