ASTM F1710-97
(Test Method)Standard Test Method for Trace Metallic Impurities in Electronic Grade Titanium by High Mass-Resolution Glow Discharge Mass Spectrometer
Standard Test Method for Trace Metallic Impurities in Electronic Grade Titanium by High Mass-Resolution Glow Discharge Mass Spectrometer
SCOPE
1.1 This test method covers the determination of concentrations of trace metallic impurities in high purity titanium.
1.2 This test method pertains to analysis by magnetic-sector glow discharge mass spectrometer (GDMS).
1.3 The titanium matrix must be 99.9 weight percent (3N-grade) pure, or purer, with respect to metallic impurities. There must be no major alloy constituent, for example, aluminum or iron, greater than 1000 weight ppm in concentration.
1.4 this test method does not include all the information needed to complete GDMS analyses. Sophisticated computer-controlled laboratory equipment skillfully used by an experienced operator is required to achieve the required sensitivity. This test method does cover the particular factors (for example, specimen preparation, setting of relative sensitivity factors, determination of sensitivity limits, etc.) known by the responsible technical committee to effect the reliability of high purity titanium analyses.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1710 – 97
Standard Test Method for
Trace Metallic Impurities in Electronic Grade Titanium by
High Mass-Resolution Glow Discharge Mass Spectrometer
This standard is issued under the fixed designation F 1710; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Surface Preparation in Spectrochemical Analysis
1.1 This test method covers the determination of concentra-
3. Terminology
tions of trace metallic impurities in high purity titanium.
3.1 Terminology in this test method is consistent with
1.2 This test method pertains to analysis by magnetic-sector
Terminology E 135. Required terminology specific to this test
glow discharge mass spectrometer (GDMS).
method, not covered in Terminology E 135, is indicated in 3.2.
1.3 The titanium matrix must be 99.9 weight % (3N-grade)
3.2 Definitions:
pure, or purer, with respect to metallic impurities. There must
3.2.1 campaign—a series of analyses of similar specimens
be no major alloy constituent, for example, aluminum or iron,
performed in the same manner in one working session, using
greater than 1000 weight ppm in concentration.
one GDMS setup.
1.4 This test method does not include all the information
3.2.1.1 Discussion—As a practical matter, cleaning of the
needed to complete GDMS analyses. Sophisticated computer-
ion source specimen cell is often the boundary event separating
controlled laboratory equipment skillfully used by an experi-
one analysis campaign from the next.
enced operator is required to achieve the required sensitivity.
3.2.2 reference sample—material accepted as suitable for
This test method does cover the particular factors (for example,
use as a calibration/sensitivity reference standard by all parties
specimen preparation, setting of relative sensitivity factors,
concerned with the analyses.
determination of sensitivity limits, etc.) known by the respon-
3.2.3 specimen—a suitably sized piece cut from a reference
sible technical committee to effect the reliability of high purity
or test sample, prepared for installation in the GDMS ion
titanium analyses.
source, and analyzed.
1.5 This standard does not purport to address all of the
3.2.4 test sample—material titanium to be analyzed for
safety concerns, if any, associated with its use. It is the
trace metallic impurities by this GDMS method.
responsibility of the user of this standard to establish appro-
3.2.4.1 Discussion—Generally the test sample is extracted
priate safety and health practices and determine the applica-
from a larger batch (lot, casting) of product and is intended to
bility of regulatory limitations prior to use.
be representative of the batch.
2. Referenced Documents
4. Summary of the Test Method
2.1 ASTM Standards:
4.1 A specimen is mounted as the cathode in a plasma
E 135 Terminology Relating to Analytical Chemistry for
2 discharge cell. Atoms subsequently sputtered from the speci-
Metals, Ores, and Related Materials
men surface are ionized, and then focused as an ion beam
E 173 Practice for Conducting Interlaboratory Studies of
2 through a double-focusing magnetic-sector mass separation
Methods for Chemical Analysis of Metals
apparatus. The mass spectrum, that is, the ion current, is
E 180 Practice for Determining the Precision of ASTM
3 collected as magnetic field or acceleration voltage, or both, is
Methods for Analysis and Testing of Industrial Chemicals
scanned.
E 691 Practice for Conducting an Interlaboratory Study to
4 4.2 The ion current of an isotope at mass M is the total
i
Determine the Precision of a Test Method
measured current, less contributions from all other interfering
E 1257 Guide for Evaluating Grinding Materials Used for
sources. Portions of the measured current may originate from
the ion detector alone (detector noise). Portions may be due to
incompletely mass resolved ions of an isotope or molecule with
This test method is under the jurisdiction of ASTM Committee F-1 on
Electronics and is the direct responsibility of Subcommittee F01.17 on Sputtered mass close to, but not identical with, M . In all such instances
i
Thin Films.
the interfering contributions must be estimated and subtracted
Current edition approved Aug. 10, 1997. Published October 1997. Originally
from the measured signal.
published as F 1710–96. Last previous edition F 1710–96.
Annual Book of ASTM Standards, Vol 03.05.
Annual Book of ASTM Standards, Vol 15.05.
4 5
Annual Book of ASTM Standards, Vol 14.02. Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1710 – 97
4.2.1 If the source of interfering contributions to the mea- 7.3 Tantalum Reference Sample.
sured ion current at M cannot be determined unambiguously, 7.4 Titanium Reference Sample.
i
the measured current less the interfering contributions from 7.4.1 To the extent available, titanium reference materials
identified sources constitutes an upper bound of the detection shall be used to produce the GDMS relative sensitivity factors
limit for the current due to the isotope. for the various elements being determined (Table 1).
4.3 The composition of the test specimen is calculated from 7.4.2 As necessary, non-titanium reference materials may be
the mass spectrum by applying a relative sensitivity factor used to produce the GDMS relative sensitivity factors for the
(RSF(X/M)) for each contaminant element, X, compared to the various elements being determined.
matrix element, M. RSF’s are determined in a separate analysis 7.4.3 Reference materials should be homogeneous and free
of a reference material performed under the same analytical of cracks or porosity.
conditions, source configuration, and operating protocol as for 7.4.4 At least two reference materials are required to estab-
the test specimen. lish the relative sensitivity factors, including one nominally
4.4 The relative concentrations of elements X and Y are 99.999 % pure (5N-grade) or better titanium metal to establish
calculated from the relative isotopic ion currents I(X ) and I(Y ) the background contribution in analyses.
i j
in the mass spectrum, adjusted for the appropriate isotopic 7.4.5 The concentration of each analyte for relative sensi-
abundance factors (A(X ), A(Y )) and RSF’s. I(X ) and I(Y ) refer tivity factor determination should be a factor of 100 greater
i j i j
to the measured ion current from isotopes X and Y , respec- than the detection limit determined using a nominally
i j
tively, of atomic species X and Y as follows: 99.999 % pure (5N-grade) or better titanium specimen, but less
than 100 ppmw.
X / Y 5 RSF X/M!/RSF Y/M!3 A Y !/A X ! 3 I X !/I Y !, (1)
@ # @ # ~ ~ ~ ~ ~ ~
j i i j
7.4.6 To meet expected analysis precision, it is necessary
where (X)/(Y) is the concentration ratio of atomic species X
that specimens of reference and test material present the same
to species Y. If species Y is taken to be the titanium matrix
size and configuration (shape and exposed length) in the glow
(RSF(M/M) = 1.0), (X) is (with only very small error for pure
discharge ion source, with a tolerance of 0.2 mm in diameter
metal matrices) the absolute impurity concentration of X.
and 0.5 mm in the distance of specimen to cell ion exit slit.
5. Significance and Use
8. Preparation of Reference Standards and Test
5.1 This test method is intended for application in the
Specimens
semiconductor industry for evaluating the purity of materials
8.1 The surface of the parent material must not be included
(for example, sputtering targets, evaporation sources) used in
in the specimen.
thin film metallization processes. This test method may be
8.2 The machined surface of the specimen must be cleaned
useful in additional applications, not envisioned by the respon-
by chemical etching immediately prior to mounting the speci-
sible technical committee, as agreed upon between the parties
men and inserting it into the glow discharge ion source.
concerned.
8.2.1 In order to obtain a representative bulk composition in
5.2 This test method is intended for use by GDMS analysts
a reasonable analysis time, surface cleaning must remove all
in various laboratories for unifying the protocol and parameters
contaminants without altering the composition of the specimen
for determining trace impurities in pure titanium. The objective
surface.
is to improve laboratory to laboratory agreement of analysis
8.2.2 To minimize the possibility of contamination, clean
data. This test method is also directed to the users of GDMS
each specimen separately immediately prior to mounting in the
analyses as an aid to understanding the determination method,
glow discharge ion source.
and the significance and reliability of reported GDMS data.
8.2.3 Prepare and use etching solutions in a clean container
5.3 For most metallic species the detection limit for routine
insoluble in the contained solution.
analysis is on the order of 0.01 weight ppm. With special
8.2.4 Useful etching solutions are HNO :HF::3:1 or
precautions detection limits to sub-ppb levels are possible.
HNO :HF:H O : :1:1:1 or H O:HNO :HF:H O ::20:5:5:4
3 2 2 2 3 2 2
5.4 This test method may be used as a referee method for
(double etched), etching until smooth, clean metal is exposed
producers and users of electronic-grade titanium materials.
over the entire surface.
8.2.5 Immediately after cleaning, wash the specimen with
6. Apparatus
high purity rinses and thoroughly dry the specimen in the
6.1 Glow Discharge Mass Spectrometer, with mass resolu-
laboratory environment.
tion greater than 3500, and associated equipment and supplies.
NOTE 1—Examples of acceptable high purity rinses are very large scale
The GDMS must be fitted with a liquid nitrogencooled
integration (VLSI) grade methanol and distilled water.
ion-source specimen cell.
6.2 Machining Apparatus, capable of preparing specimens
8.3 Immediately mount and insert the specimen into the
and reference samples in the required geometry and with
glow discharge ion source, minimizing exposure of the
smooth surfaces.
cleaned, rinsed, specimen surface to the laboratory environ-
ment.
7. Reagents and Materials
8.3.1 As necessary, use a noncontacting gage when mount-
7.1 Reagent and High Purity Grade Reagents, as required ing specimens in the analysis cell specimen holder to ensure
(MeOH, HNO ,HF, H O ). the proper sample configuration in the glow discharge cell (see
3 2 2
7.2 Demineralized Water. 7.4.6).
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1710 – 97
TABLE 1 Suite of Impurity Elements to be Analyzed, with
8.4 Sputter etch the specimen surface in the glow discharge
Appropriate Isotope Selection
plasma for a period of time before data acquisition (12.3) to
ensure the cleanliness of the surface. Pre-analysis sputtering
NOTE 1—Establish RSFs for the following suite of elements, using the
indicated isotopes for establishing RSF values and for performing
conditions can be limited by the need to maintain sample
analyses of test specimens.
integrity. If sputter cleaning and analysis are carried out under
NOTE 2—This selection of isotopes minimizes significant interferences
different plasma conditions, accuracy should be established for
(see Annex A1.). Additional species may be determined and reported, as
the analytical protocol adopted and elements measured.
agreed upon by all parties concerned with the analyses. Other isotopes can
be selected to assist mass spectrum peak identification or for other
9. Preparation of the GDMS Apparatus
purposes.
9.1 The ultimate background pressure in the ion source
Lithium Li
−6
chamber should be less than 1 3 10 torr before operation.
Beryllium Be
Boron B
The background pressure in the mass analyzer should be less
Carbon C −7
than 5 3 10 torr during operation.
Nitrogen N
9.2 The glow discharge ion source must be cooled to near
Oxygen O
Fluorine F
liquid nitrogen temperature.
Sodium Na
26 9.3 The GDMS instrument must be accurately mass cali-
Magnesium Mg
brated prior to measurements.
Aluminum Al
Silicon Si
9.4 The GDMS instrument must be adjusted to the appro-
Phophorus P
32 priate mass peak shape and mass resolving power for the
Sulfur S
Chlorine Cl
required analysis.
Potassium K
9.5 If the instrument uses different ion collectors to measure
Calcium Ca
ion currents during the same analysis, the measurement effi-
Scandium Sc
Titanium Ti
ciency of each detector relative to the others should be
Vanadium V
determined at least weekly.
Chromium Cr
9.5.1 If both Faraday cup collector for ion current measure-
Manganese Mn
Iron Fe
ment and ion counting detectors are used during the same
Cobalt Co
analysis, the ion counting efficiency (ICE) must be determined
Nickel Ni
prior to each campaign of specimen analyses using the follow-
Copper Cu
66 68
Zinc Zn or Zn
ing or equivalent procedures:
69 71
Gallium Ga or Ga
9.5.1.1 Using a specimen of tantalum, measure the ion
70 73
Germanium Ge or Ge
current from the major isotope ( Ta) using the ion current
Arsenic As
Selenium Se
Faraday cup detector, and measure the ion current from the
Bromine Br
85 minor isotope ( Ta) using the ion counting detector, with care
Rubidium Rb
to avoid ion counting losses due to ion-counting system dead
Yttrium Y
Zirconium Zr
times. The counting loss should be 1 % or less.
Niobium Nb
100 9.5.1.2 The ion counting efficiency is calculated by multi-
Molybdenum Mo
180 181
Ruthenium Ru plying the ratio of the Ta ion current to the Ta ion current
181 180
Rhodium Rh
by the Ta/ Ta isotopic ratio. The result of this calculation
Silver Ag
106 108
is the ion counting detector efficiency (ICE).
Palladium Pd or Pd
Cd
Cadmium 9.5.1.3 Apply the ICE as a correction to all ion current
Indium In
measurements from the ion counting detector obtained in
117 119
Tin Sn or Sn
analyses by dividing the ion current by the ICE factor.
Antimony Sb
Iodine I
125 130
Tellurium Te or Te 10. Instrument Quality Control
Cesium Cs
10.1 A well-characterized specimen must be run on a
Barium Ba
Lanthanum La
regular basis to demonstrate the capability of the GDMS
Cerium Ce
syst
...
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