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SEMI C3.47-11 01 © SEMI 1993 , 2001 3 4.3.4 Sampling Gas eous Hydrogen B romide 4.3.4.1 Assemble sa m pling app aratus in laboratory hood for s afety. 4.3.4.2 Fill gas washing bottles (scr ubbers) with 75 mL 18 m egaohm-…

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SEMI C3.47-1101 © SEMI 1993, 2001 2
4.1.4.2 Analyze the HBr sample to be tested in the
same manner.
4.1.4.3 Analyze the calibration standard again.
4.1.4.4 Compare the average peak area of the
calibration standard to that of the HBr sample being
tested. Calculate the concentration of impurities, using
the formula below. The result may not exceed the
specification in Section 2 of this standard.
Sample Peak Are
a
Standard Peak Are
a
×
Concentratio
n
of Standard
=
Concentratio
n
of Sample
4.2 Water — This procedure is for the determination of
trace moisture (water) in hydrogen bromide gas using a
continuous flowing, cooled surface condensation point
hygrometer.
NOTE 1: The National Institute of Standards and Technology
(NIST) provides calibration services for the thermometer used
in condensation point hygrometers.
NOTE 2: This method is not applicable if other constituents
in the gas will condense before the moisture condensation i.e.,
excessive carbon dioxide and/or oil contamination.
NOTE 3: The sampling system and hygrometer must be
designed to operate under the sample pressure, or the sample
pressure must be reduced to accommodate the pressure
restrictions of the analytical hygrometer using a regulator with
a stainless steel diaphragm.
4.2.1 Detection Limit — 2.0 ppm.
4.2.2 Flow Requirements:
4.2.2.1 Sample flow rate and pressure will be set in
accordance with the instrument manufacturer’s
instructions.
4.2.2.2
Gas must flow past the chilled mirror where
optic means are provided to detect the deposit
(condensation) and to read the thermometer measuring
the temperature of the mirror.
4.2.3
Calibration
4.2.3.1 A calibration thermometer designed to indicate
temperatures in the –89°C (–121°F) range is required.
4.2.3.2 A calibration curve representing water added to
dried hydrogen bromide vs condensation point is
required. This can be obtained by preparing a standard
of water balance nitrogen and mixing it with dry
hydrogen bromide using a dynamic gas blender with
mass flow controllers or calibrated flow meters. The
hydrogen bromide gas can be dried by passing it over
an activated molecular sieve (5A) or magnesium
perchlorate.
4.2.4
Operating Procedures
4.2.4.1 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.
4.2.4.2
After prepurging with a dry gas, allow the
sample gas to flow through the sampling system and the
condensation point hygrometer for one-quarter hour to
two hours to allow the entire system to reach
equilibrium with regard to moisture content.
4.2.4.3
After equilibrium has been reached, cool the
mirror to determine the actual condensation point of the
sample. Follow the manufacturer’s recommendations
to create the temperatures needed.
4.2.4.4
Continue to verify the condensation point for at
least 30 minutes after a stable reading has been
confirmed.
4.2.4.5
Correct the condensation point reading from the
measured pressure to 1 atm of pressure. The result may
not exceed the specification in Section 2 of this
standard.
4.3
Iron — This procedure is for the determination of
iron in gaseous hydrogen bromide and analyzed by
inductively coupled plasma.
4.3.1
Sampling Apparatus
• 3 Teflon diaphragm valves (1/4" FNPT)
(Fluoroware 201-10 or equivalent)
• 2 Teflon tees (1/4") (Fluoroware UT4FN-1 or
equivalent)
•
50 ft. Teflon tubing (1/4") (Fluoroware AT250-047
or equivalent)
• Teflon flow meter (1/4" FNPT calibrated for HBr
flow) (Fluoroware FM-4N-1P or equivalent)
• 8 Teflon connectors (1/4" tube to 1/4" MNPT
(Fluoroware C4-CFN-1 or equivalent)
• 9 gas washing bottles (375 mL) (Savillex #507 or
equivalent with 501-4-2 cap)
•
Tee purge assembly (Matheson 4756-330 or
equivalent)
• Manual control valve (Matheson 55A-330 or
equivalent)
•
Cylinder scale that can measure the mass of the
cylinder to ± 1 g accuracy.
4.3.2 Water — 18 megaohm-cm DI water is used for
all dilution blanks and washings.
4.3.3
Reagents — All reagents are of the highest purity
available minimizing background metal contamination.
SEMI C3.47-1101 © SEMI 1993, 20013
4.3.4 Sampling Gaseous Hydrogen Bromide
4.3.4.1 Assemble sampling apparatus in laboratory
hood for safety.
4.3.4.2 Fill gas washing bottles (scrubbers) with 75 mL
18 megaohm-cm DI water.
4.3.4.3
Start nitrogen purge to remove air from system
and to check for leaks.
4.3.4.4 Close V4 and nitrogen purge.
4.3.4.5 Close V2.
4.3.4.6 Open V1 and V3.
4.3.4.7 Open V2 and controlling flow rate at 1 L/min
taking care not to over-pressurize system.
4.3.4.8 Continue flow through scrubber train #1 until
scale shows that approximately 100 grams of HBr have
been purged.
4.3.4.9
Open V4 and close V3. Record the weight of
HBr cylinder.
4.3.4.10
Collect 100 grams of HBr in scrubber train #2.
Close V1 and record weight of HBr sampled.
4.3.4.11 Open nitrogen purge and purge lines, scrubber
train #1 and scrubber train #2, before disconnecting
scrubbers.
4.3.5
Sample Preparation
4.3.5.1 For each scrubber train, quantitatively wash
with DI water and add to 250 mL volumetric.
4.3.5.2 Wash associated tubing of each scrubber train
with DI water and add to the 250 mL volumetric.
4.3.5.3 Make up reagent blank of water from the same
lot of DI water used in the sampling.
4.3.6
Calibration — Make calibration standards by
serial dilution of standard iron solution which is matrix
matched traceable to NIST.
4.3.7
Instrument Parameters — Perform analysis on an
inductively coupled plasma spectrometer or equivalent
technique employing operating procedures suggested
by manufacturer. Correct result to ppm (ppmw) basis
on HBr used.
4.4
Chloride Ion — This procedure is for the
determination of chloride ion in gaseous hydrogen
bromide using ion chromatography.
4.4.1
Detection Limit — 5 ppb wt/vol.
4.4.2 Sample was prepared as in Section 4.3.5. The 250
mL aqueous sample was diluted further 500 to 1, by
diluting one milliliter of 250 mL aqueous sample with
DI water in a 500 mL volumetric flask.
4.4.3
Instrument Parameters
4.4.3.1 Flow:
• Eluent l0 mM NaOH at 1 cc/min.
• Regenerate 25 mM H
2
SO
4
at 7 psi.
4.4.3.2 Column — AS5A with AG5A guard column
4.4.3.3 Sample Size — 25 microliters.
4.4.3.4 Program — Boost eluent concentration to 100
mM NaOH after elution of chloride peak (4.3 min).
Continue 100 mM eluent flow for 7 minutes to elute
bromide peak. Return to 10 mM NaOH at 12 minutes.
Allow to equilibrate for 6 minutes.
4.4.4
Calibration — A multi-point calibration curve is
constructed in the range of 10 ppb to 250 ppb (wt/vol)
employing standards traceable to NIST.
4.4.5
Use procedures provided by manufacturer of ion
chromatograph. Correct results and calculate them to
pure HBr on a weight/weight basis.
SEMI C3.47-1101 © SEMI 1993, 2001 4
Figure 1
Column Configuration for the Analysis of CO, CO
2
, and Hydrocarbons
Figure 2
Iron Analysis Sampling Apparatus