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SEMI C3.51-11 01 © SEMI 1995 , 2001 5 Figure 1 Chromatogra m Showing the Dete rmination of Nit rogen in Boron Trichlor ide Figure 2 Chromatogram Showing the De termination of Carbon Dioxide in Boron Trichloride Figure 3 …

SEMI C3.51-1101 © SEMI 1995, 2001 4

Cleaning of lines, flow meters and valves shall be completed

before a new cylinder has to be analyzed and shall be repeated

after 10 samplings, or if a new cylinder has to analyzed. The

impingers must be rinsed with water after each sampling.

Before a new cylinder has to be analyzed and after five

samplings, the impingers must be cleaned using the above

described procedures. Drying of the impingers is not

recommended (contamination risks).

NOTE 8: Cleaning of cylinder valve.

Clean outside (visible parts, threads) with wipe. Clean the

interior parts of the valve-outlet with methanol or isopropanol

using a syringe, followed by a purge with filtered gas.

7.5 Iron and Nickel — This procedure is for the

determination of iron and nickel in gas phase boron

trichloride using atomic absorption or inductive coupled

plasma methods.

7.5.1

Detection Limits

7.5.2 Instrument Parameters — Operate the designated

analytical instruments according to the manufacturer’s

instructions.

7.5.3

Sampling Procedure

7.5.3.1 Clean all metallic and plastic components

according to the procedures described in Notes 6 and 7.

Use 18 MΩcm water.

7.5.3.2

Connect all components of the sampling

system.

NOTE 9: The apparatus is charged with sufficient water to

just cover the rim of the funnel (approximately 100 ml). A

magnetic stirrer is introduced and the apparatus closed.

7.5.3.3 Connect the sampling system to the sample

boron trichloride cylinder (see Note 8).

7.5.3.4 Purge with filtered argon (< 0.01 µ) at

approximately 1 L/min. for 15 minutes prior to

sampling. During this period, the apparatus is inclined

so as to allow a higher flow rate without excessive

agitation of the water.

NOTE 10: Due to the design of the apparatus, suck-back

should be prevented, but this must be guarded against. A

bubble rate of about one per second should be set.

7.5.3.5 While observing the sampling apparatus,

operate the needle valve to admit sample slowly to the

sampling apparatus. Initial absorption will be fast.

7.5.3.6

The sample flow is halted when no further

absorption seems to be taking place (i.e., when bubble

rate increases at the vent).

7.5.3.7

The argon purge is re-established for a further

15 minutes.

7.5.3.8 The apparatus is allowed to cool and the

contents quantitatively transferred to a 250 ml

polypropylene flask.

NOTE 11: The solution prepared above will contain some

crystals of boric acid which have come out of solution during

cooling. For the purpose of analysis, the concentration of

boric acid must be reduced. Also the amount of BCl

samples

need to be determined.

7.5.3.9 A 5 ml aliquot of the solution is titrated against

1 M NaOH using methyl red as an indicator. The

quantity of sample boron trichloride taken is then

calculated.

7.5.3.10

A sample of the solution is diluted × 10 with

water. The aliquot is taken from the supernatant liquid.

7.5.3.11

Analysis is carried out in a suitable analyzer

capable of meeting the required detection limits. A

blank solution of 1% hydrochloric acid is used.

Yttrium is used as an internal standard at a level of 0.2

ppm added to all analysis solutions.

7.5.3.12

Calibration curves are prepared using standard

solutions covering the elements required. Traceable

standards can be obtained from national and

international bodies.

7.5.3.13

Calculate the concentration of iron and nickel

content using the calibration curve and the volume of

boron trichloride sampled.

Figure 1

Chromatogram Showing the Determination of Nitrogen in Boron Trichloride

Figure 2

Chromatogram Showing the Determination of Carbon Dioxide in Boron Trichloride

Figure 3

Chromatogram Showing the Determination of Chlorine in Boron Trichloride

Figure 4A

Infra Red Absorption Spectra of Hydrogen Chloride in Boron Trichloride

Figure 4B

Infra Red Absorption of Phosgene in Boron Trichloride