semi合集-English.pdf - 第4107页
SEMI F60-0301 © SEMI 2001 3 9.2 St atistical Proces s Control Ma t e rial — A no minal 316L material wi th a composition rang e within the guidelin es of ASTM A276. The com position of t he bulk material shoul d be deter…
SEMI F60-0301 © SEMI 2001 2
E1078 — Standard Guide for Specimen Handling in
Auger Electron Spectroscopy and X-ray Photoelectron
Spectroscopy.
4.3 NIST Standard
2
SRD20 — NIST X-ray Photoelectron Spectroscopy
Database.
4.4 Physical Electronics
3
Moulder, et al. — Handbook of X-ray Photoelectron
Spectroscopy.
5 Terminology
5.1 Acronyms and Abbreviations
5.1.1 ESCA — Electron Spectroscopy for Chemical
Analysis.
5.1.2 XPS — X-ray Photoelectron Spectroscopy, an
equivalent name for ESCA.
5.2 Definitions
5.2.1 sampling volume — the volume from which
photoelectrons are detected. The x-ray spot size and/or
the lens and aperture system of the electron analyzer
determine lateral dimensions. A length of three times
the photoelectron mean free path is considered the
maximum depth sensitivity. Sampling volume is
dependent on the sample material and TOA. The
acceptance angle of the analyzer will also influence the
distribution of the depth information.
5.2.2 take-off angle (TOA) — the angle that the
collection lens forms with the sample plane.
6 Summary of Method
6.1 Data Acquisition
6.1.1 Acquire elemental survey and calculate
elemental composition of “as received” wetted surface.
6.1.2 Acquire chromium and iron regions at high
resolution. Calculate total Cr/Fe ratio and Cr oxide/Fe
oxide ratios from these regions.
6.1.3 Acquire a compositional depth profile to
determine the relative abundance of C, O, Cr, Fe and
Ni. Additional elements may be included as desired
(i.e., molybdenum, silicon and nitrogen). If minor
elements are included in the profile the instrument
parameters should be chosen to allow for a detection
limit of 1 atomic percent (at%) or better.
6.2 Reporting — Data is provided consisting of:
2 National Institute of Standards and Technology, Gaithersburg, MD
20899
3 Physical Electronics, Eden Prairie, MN 55344
6.2.1 A survey spectrum extending from at least 0-
1100eV.
6.2.2 The high-resolution Cr (2p
3/2
) and Fe (2p
3/2
)
spectra from the as-received surface.
6.2.3 A compositional depth profile plot including C,
O, Cr, Fe and Ni as a function of sputtering time.
7 Possible Interferences
7.1 Mo (3d) and S (2s) — use S (2p) for quantification
of sulfur. Molybdenum will appear as a doublet;
quantity may be overestimated.
7.2 Fe (2p
3/2
) and Ni Auger — ignore.
7.3 Mo (3p) and N (1s) — the ability to accurately
quantify the nitrogen will depend upon the chemical
state of both the nitrogen and molybdenum. In some
cases the nitrogen will be overestimated from a survey
scan quantification.
8 Apparatus
8.1 Instrumentation — Any ESCA instrument with
definable area of analysis approximately 1 mm or less
and sufficient count rate to provide detection of low
level contaminants at one atomic percent or greater. A
count rate of at least 100,000 counts per minute for
clean Au (4f
7/2
) should indicate sufficient sensitivity.
8.2 The instrument should have peak resolution of 1
eV FWHM Au (4f
7/2
) or better (i.e., < 1 eV) to ensure
species separation of metallic and oxide forms of
chromium and iron.
8.3 If the instrument is of a variable take-off angle
(TOA) design, the geometry should be set to a TOA of
approximately 35
o
. Instruments with geometries
significantly different from this, or with magnetic
electron collection lens may provide analysis from a
different sampling volume. The angle of the incident
X-ray irradiation with respect to the sample plane and
TOA must be recorded.
8.4 Data reduction software must have the ability to
select an iterated Shirley-curve background.
9 Reagents and Materials
9.1 Instrument Calibration Materials — Refer to
instrument manufacturer recommendations or ASTM
E902. A measurement of the binding energy difference
between the Au (4f
7/2
) at 84.0 eV and Cu (2p
3/2
) at
932.6 eV is an acceptable method of calibrating
analyzer linearity. A value of ± 3σ based upon a
minimum of 10 historical measurements of less than ±
0.25 eV is acceptable.
SEMI F60-0301 © SEMI 20013
9.2 Statistical Process Control Material — A nominal
316L material with a composition range within the
guidelines of ASTM A276. The composition of the
bulk material should be determined by methods
consistent with ASTM A751.
10 Safety Precautions
10.1 This test method does not purport to address the
safety considerations associated with use of high
voltage, vacuum, and X-ray producing equipment. The
method assumes an ESCA analyst with knowledge of
instrumentation and associated safety precautions.
11 Test Specimen
11.1 Specimens are to be sectioned to appropriate size
for the particular ESCA instrument using a clean, dry
hacksaw or dry low speed bandsaw. Any sample
preparation shall avoid introducing contamination onto
the surface to be measured. In addition, preparation
must avoid excessive heating of the sample, i.e., the
surface temperature shall not exceed 50
o
C, to avoid
oxide growth or change in surface composition.
11.2 Sample preparation should preferably be done by
the component manufacturer. Following sectioning the
sample(s) are to be cleaned and packaged per the
manufacturer’s standard final cleaning and packaging
procedures.
11.3 If sample preparation is done by other than the
manufacturer, the sample(s) may be cleaned in DI
water. If the sample(s) are not to be analyzed
immediately they should be packaged by wrapping in
clean metal foil or sealing in cleanroom quality nylon
bags.
11.4 If sample preparation is done by other than the
manufacturer this shall be stated in the report narrative
and the analytical results are not to be interpreted as
indicative of the manufacturer’s quality of cleaning and
packaging procedures. A note to this effect shall be
included in all tables of reported results of the
composition of the surface.
11.5 After preparation, samples should be analyzed
promptly, with allowance for shipping times and
queuing time at the analyst.
12 Preparation of Apparatus
12.1 Instruments shall be routinely tested in
accordance with manufacturer recommendations to
assure proper performance. The instrument vacuum
shall be 1.0E-7 Torr or better during the analysis.
13 Calibration and Standardization
13.1 Proper instrument calibration is necessary to
provide the most accurate and reproducible results,
particularly if results are compared among different
laboratories. Instrument calibration for sensitivity
factors and binding energies shall be performed in
accordance with the instrument manufacturer
recommendations or other accepted method, such as
that provided in ASTM E902.
13.2 The general ESCA calibration procedures
described above are suitable for most analyses and
provide reasonably accurate relative quantitative
information regarding the surface chemistry. However,
in order to establish the most accurate measurement
practical and to maintain the desired level of
reproducibility over time, an application-specific
statistical process control (SPC) shall be established for
this test method to determine the appropriate sensitivity
factors for Cr, Fe, Ni and Mo in 316L stainless steel.
The bulk composition of the SPC material should have
an assay consistent with the acceptable composition
range of 316L for Cr, Fe, Ni and Mo, as set forth in
ASTM A276. The bulk composition of the SPC
material should be determined by methods consistent
with ASTM A751. The relative sensitivity factors
established for the quantification of data should reflect
the nominal composition of the bulk 316L SPC
standard after a sputter cleaning sufficient to remove
any surface contamination and the oxide passive layer.
A ± 3σ relative precision should be established from a
minimum of 10 SPC measurements with the following
tolerances:
Cr ± 10%
Fe ± 10%
Ni ± 25%
Mo ± 30%
As referenced from ASTM A276-97, a typical 316L
material has a composition range in terms of wt% of:
Cr 16–18
Ni 10–14
Mo 2–3
C < 0.03
Mn < 2.0
P < 0.045
S < 0.03
Si < 1.0
N< 0.1
Fe Balance.
Note that ESCA data is reported in atomic percent.
13.3 The sputter conditions established for the SPC
surface cleaning shall be the same as those established
for the ESCA depth profile measurement part of this
SEMI F60-0301 © SEMI 2001 4
standard. A minimum sputtering etch cleaning of the
SPC sample of ≥ 10 nanometers is recommended in
order to remove surface contamination, the oxide
passive layer and establish equilibrium. Note that the
degree of preferential sputtering and other ion etching
artifacts are a function of the matrix material and the
ion gun conditions.
13.4 Calibration frequency of the application specific
SPC should be designed to establish a record of the
reproducibility and accuracy of the measurement, as
reflected by the nominal composition of the 316L
standard. A minimum frequency of one per week is
recommended, or immediately prior to performing a
measurement in accordance with this test method.
13.5 A sputter rate calibration shall be performed prior
to an ESCA profile measurement conducted in
accordance to this test method. The ion sputter rate
determination shall be made using standard thin films
of 100 nanometers or less of SiO
2
on Si. The method of
determining the thickness of the oxide film shall be
based upon the oxygen concentration profile. The
oxide – substrate interface shall be specified as the
point at which the oxygen concentration decreases to ½
its maximum value in the SiO
2
film, ignoring the first
sputter cycle.
13.6 Multiple samples may be analyzed following a
single sputter rate determination if the ion gun
parameters have not been adjusted and the ion gun
performance is documented as stable over the period in
question.
14 Procedure
14.1 As-Received Surface Analysis— The sample is to
be mounted in accordance with manufacturer's
recommendations and in a manner consistent with ultra-
high vacuum surface analytical procedures. Some of
these practices are detailed in ASTM-E1078. The area
to be analyzed should be mounted parallel to the sample
holder surface so that TOA is well known.
14.1.1 Place the sample in the ESCA introduction
chamber for pump down. Transfer to the analytical
chamber at the manufacturer's recommended base
pressure. Align the sample with respect to the X-ray
beam and analyzer so that optimum count rate from the
desired analytical location is obtained. The use of a
collimated high voltage electron beam to align the
sample should be avoided, as this may pyrolyze surface
carbon and potentially alter surface oxide chemistry.
The surface area to be analyzed should be free of
visible particles and large defect features, if possible.
14.1.2 A beam size as close to 1 mm as possible
should be used to ensure measurement of a
representative surface. If surface curvature is great
(e.g., < 1/4" tubing), a smaller beam may be employed.
Elemental survey data (0–1100 eV) are to be measured
from the sample surface to determine the elements
present and their approximate surface abundance. A
high throughput analyzer setting may be used to obtain
a signal to noise ratio (S/N) sufficient to detect common
surface contaminants such as sulfur and phosphorus at
one atomic percent or better.
14.1.3 Using instrument settings sufficient to provide
a FWHM peak width of 1.0 eV or less on Au (4f
7/2
),
measure chromium, iron, and carbon regions. A typical
region width is 20 eV. Suggested ranges are as follows:
Cr (2p
3/2
) from 570 to 590 eV, Fe (2p
3/2
) from 700 to
720 eV, and C (1s) from 275 to 295 eV. Signal to noise
ratios of greater than 20 are suggested.
14.1.4 A consistent method of data reduction of high-
resolution surface spectra is necessary in order to
provide meaningful comparison of the relative Cr:Fe
ratios.
14.1.5 The spectra shall be charge compensated with
respect to the maximum of the Cr (2p
3/2
) set to 577 eV.
An iterated Shirley method of background subtraction
shall be applied to the Fe (2p
3/2
) and Cr (2p
3/2
) spectral
regions, using a minimum of three iterations.
14.1.6 The curve fit regions shall typically extend
from:
Cr (2p
3/2
) 570–582 eV
Fe (2p
3/2
) 704–717 eV
14.1.7 The curve fit peak parameters should be
initialized as follows:
Cr (2p
3/2
) Peak Position FWHM % gaussian
1 574 1.5 80
2 576.5 2.0 80
3 577.5 2.0 80
Fe (2p
3/2
) Peak Position FWHM % gaussian
1 707 1.0 80
2 708 1.0 80
3 710 1.4 80
4 711.5 1.4 80
5 713 1.4 80
14.1.8 The curve fit routine should apply the following
tolerances for the band limit parameters of all peaks
defined above:
FWHM delta
≤ 0.2 eV
% gaussian delta
≤ 10%
Curve fit position delta
≤ 0.25 eV
14.1.9 An automated form of data reduction is
recommended to enhance reproducibility and minimize