ISO/PRF 13084
(Main)Surface chemical analysis — Mass spectrometries — Calibration of the mass scale for a time-of-flight secondary ion mass spectrometer
Surface chemical analysis — Mass spectrometries — Calibration of the mass scale for a time-of-flight secondary ion mass spectrometer
This document specifies a method to optimize the mass calibration accuracy in time-of-flight secondary ion mass spectrometry (SIMS) instruments used for general analytical purposes. It is only applicable to time-of-flight instruments but is not restricted to any particular instrument design. Guidance is provided for some of the instrumental parameters that can be optimized using this procedure and the types of generic peaks suitable to calibrate the mass scale for optimum mass accuracy.
Titre manque
General Information
Relations
Standards Content (Sample)
International
Standard
ISO 13084
Third edition
Surface chemical analysis — Mass
spectrometries — Calibration of
the mass scale for a time-of-flight
secondary ion mass spectrometer
PROOF/ÉPREUVE
Reference number
ISO 13084:2025(en) © ISO 2025
ISO 13084:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
ISO 13084:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 1
4.1 Symbols .1
4.2 Abbreviated terms .2
5 Outline of method . 2
6 Method for improving mass accuracy . 3
6.1 Obtaining the reference sample for optimization .3
6.2 Preparation of polycarbonate sample.3
6.3 Obtaining the SIMS spectral data .4
6.4 Calculating mass accuracy .4
6.5 Optimizing instrumental parameters .7
6.6 Calibration procedure .8
Annex A (informative) Calibration uncertainty . 10
Annex B (informative) Internal addition method .11
Bibliography .13
PROOF/ÉPREUVE
iii
ISO 13084:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 201, Surface chemical analysis, Subcommittee
SC 6, Mass spectrometries.
This third edition cancels and replaces the second edition (ISO 13084:2018), which has been technically
revised.
The main changes are as follows:
— addition of informative Annex B.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
PROOF/ÉPREUVE
iv
ISO 13084:2025(en)
Introduction
Secondary ion mass spectrometry (SIMS) is a powerful technique for the analysis of organic and molecular
surfaces. Over the last decade, instrumentation has improved significantly so that modern instruments
[2]
now have very high repeatability and constancy . A growing need is for the identification of the chemical
composition of complex molecules from accurate measurements of the mass of the secondary ions. The
relative mass accuracy to do this and to distinguish between molecules that contain different chemical
constituents, but are of the same nominal mass (rounded to the nearest integer mass), is thus an important
parameter. A relative mass accuracy of better than 10 ppm is required to distinguish between C H
2 4
(28,031 30 u) and Si (27,976 92 u) in a parent ion with total mass up to 1 000 u, and between CH (14,015 65 u)
and N (14,003 07 u) in parent ions with total mass up to 300 u. However, in a recent interlaboratory
[3]
study , the average fractional mass accuracy was found to be 150 ppm, which is significantly worse than
[4]
the accuracy needed for unambiguous identification of ions. A detailed study shows that the key factors
degrading the accuracy include the large kinetic energy distribution of secondary ions, non-optimized
instrument parameters and extrapolation of the mass scale calibration.
This document describes a simple method, using locally sourced material, to optimize the instrumental
parameters, as well as a procedure to ensure that accurate calibration of the mass scale is achieved within a
selectable uncertainty.
PROOF/ÉPREUVE
v
International Standard ISO 13084:2025(en)
Surface chemical analysis — Mass spectrometries —
Calibration of the mass scale for a time-of-flight secondary
ion mass spectrometer
1 Scope
This document specifies a method to optimize the mass calibration accuracy in time-of-flight secondary
ion mass spectrometry (SIMS) instruments used for general analytical purposes. This document is only
applicable to time-of-flight instruments but is not restricted to any particular instrument design. This
document gives guidance for some of the instrumental parameters that can be optimized using this
procedure and the types of generic peaks suitable to calibrate the mass scale for optimum mass accuracy.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols and abbreviated terms
4.1 Symbols
m mass of interest
m calibration mass 1
m calibration mass 2
M mass (u)
M peak centre (u)
ΔM mass accuracy (u)
M measured peak mass (u)
P
M true mass (u)
T
U(m) mass uncertainty for a mass, m, arising from calibration
U uncertainty in the accurate mass measurement of m
1 1
U uncertainty in the accurate mass measurement of m
2 2
PROOF/ÉPREUVE
ISO 13084:2025(en)
U average uncertainty in an accurate mass measurement
V reflector or acceptance voltage (V)
R
W relative mass accuracy
x number of carbon atoms
y number of hydrogen atoms
G scaling term
α asymmetry term
σ(ΔM) standard deviation of the mass accuracy for a number of peaks
+
σ average of the standard deviations of ΔM for each of the four C H cascades with 4, 6, 7 and 8 car-
M x y
bon atoms
4.2 Abbreviated terms
MEMS micro-electromechanical system
PC polycarbonate
ppm parts per million
r/min revolutions per minute
SIMS secondary ion mass spectrometry
THF tetrahydrofuran
ToF time-of-flight
5 Outline of method
Here, the method is outlined so that the detailed procedure, given in Clause 6, can be understood in
context. First, to optimize a time-of-flight mass spectrometer using this procedure, obtain a thin film of
polycarbonate (PC) on a conducting substrate (silicon). The optimization procedure is achieved by carrying
out the procedures in 6.3 to 6.5 iteratively; it uses 19 specific C H peaks in the PC positive-ion mass
x y
spectrum. In 6.6, a general calibration procedure is given which provides the rules by which calibrations
for inorganics and organics may be incorporated. This leads to a new generic set of ions for mass calibration
that can improve the mass accuracy from some often-used calibrations by a factor of five. The effects of
extrapolation beyond the calibration range are discussed and a recommended procedure is given to
ensure that accurate mass is achieved, within a selectable uncertainty, for large molecules. Therefore, the
procedure has two parts, optimization and calibration. Subclauses 6.1 to 6.5 are only required as part of the
regular maintenance of the instrument as defined by the testing laboratory. Subclause 6.6 is required for all
calibrations of the mass scale. This is summarized in the flowchart in Figure 1.
PROOF/ÉPREUVE
ISO 13084:2025(en)
Figure 1 — Flowchart of sequence of operations of the method
6 Method for improving mass accuracy
6.1 Obtaining the reference sample for optimization
A sample of thin (10 nm to 100 nm) PC on a flat conducting substrate (e.g. silicon wafer) shall either be
obtained or prepared, as described in 6.2.
6.2 Preparation of polycarbonate sample
6.2.1 Instructions for the preparation of a PC reference sample are provided. This method can give sample-
[2]
to-sample repeatability in ToF SIMS spectra of better than 1,9 % . To prepare such a sample for static SIMS
analysis requires a clean working environment. To reduce surface contamination, clean glassware, tweezers
and powderless gloves shall be used. The equipment required is a 1 ml glass pipette, a 100 ml glass-stoppered
measuring flask and a device for spin casting. If a device for spin casting is not available, droplet deposition
of the PC solution may be used. However, this will give poor repeatability, which will need to be carefully
taken into account during spectral analysis.
6.2.2 Using poly(bisphenol A carbonate), abbreviated to PC, weigh out 100 mg on a clean piece of
aluminium foil. Introduce the PC into the 100 ml, glass-stoppered measuring flask, add tetrahydrofuran
(THF) of analytical reagent quality to the 100 ml level line. Shake the flask to mix the PC and allow time to
dissolve it completely. This produces a 1 mg/ml solution of PC in THF. The aluminium foil shall be freshly
unrolled and the shiny surface used. Ensure that the THF is anhydrous, otherwise streaks will appear from
water when spin coating, as described in 6.2.3. The shelf life of freshly prepared stock solution shall be no
more than one month owing to water
...
Date: 2025-01-20
ISO/DISPRF 13084:2025(en)
ISO/TC 201/SC 6/WG 4
Secretariat: JISC
Date:
Surface chemical analysis — Mass spectrometries — Calibration of
the mass scale for a time-of-flight secondary ion mass spectrometer
Analyse chimique des surfaces — Spectrométrie de masse des ions secondaires — Étalonnage de l'échelle de
masse pour un spectromètre de masse des ions secondaires à temps de vol
PROOF
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO'sISO’s member body in the country of the requester.
ISO Copyright Officecopyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Email: copyright@iso.org
E-mail: copyright@iso.org
Website: www.iso.orgwww.iso.org
Published in Switzerland.
ii
ISO/DISPRF 13084:2025(en)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 1
5 Outline of method . 2
6 Method for improving mass accuracy . 4
Annex A (informative) Calibration uncertainty . 13
Annex B (informative) Internal addition method . 15
Bibliography . 18
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 201, Surface chemical analysis, Subcommittee
SC 6, Mass spectrometries.
This thirdeditionthird edition cancels and replaces the second edition (ISO 13084:2018), which has been
technically revised.
The main changes are as follows:
— — addition of informative Annex B.Annex B.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
Field Code Changed
iv
ISO/DISPRF 13084:2025(en)
Introduction
Secondary ion mass spectrometry (SIMS) is a powerful technique for the analysis of organic and molecular
surfaces. Over the last decade, instrumentation has improved significantly so that modern instruments now
[2]
[ ]
have very high repeatability and constancy. 0 . A growing need is for the identification of the chemical
composition of complex molecules from accurate measurements of the mass of the secondary ions. The
relative mass accuracy to do this and to distinguish between molecules that contain different chemical
constituents, but are of the same nominal mass (rounded to the nearest integer mass), is thus an important
parameter. A relative mass accuracy of better than 10 ppm is required to distinguish between C H
2 4
(28,031 30 u) and Si (27,976 92 u) in a parent ion with total mass up to 1 000 u, and between CH
(14,015 65 u) and N (14,003 07 u) in parent ions with total mass up to 300 u. However, in a recent
[3]
[ ]
interlaboratory study, 0 , the average fractional mass accuracy was found to be 150 ppm, which is
[4]
[ ]
significantly worse than the accuracy needed for unambiguous identification of ions. A detailed study 0
shows that the key factors degrading the accuracy include the large kinetic energy distribution of secondary
ions, non-optimized instrument parameters and extrapolation of the mass scale calibration.
This document describes a simple method, using locally sourced material, to optimize the instrumental
parameters, as well as a procedure to ensure that accurate calibration of the mass scale is achieved within a
selectable uncertainty.
v
DRAFT International Standard ISO/DIS 13084:2025(en)
Surface chemical analysis — Secondary ion mass spectrometry — Mass
spectrometries — Calibration of the mass scale for a time-of-flight
secondary ion mass spectrometer
1 Scope
This document specifies a method to optimize the mass calibration accuracy in time-of-flight secondary ion
mass spectrometry (SIMS) instruments used for general analytical purposes. This document is only applicable
to time-of-flight instruments but is not restricted to any particular instrument design. This document gives
guidance for some of the instrumental parameters that can be optimized using this procedure and the types
of generic peaks suitable to calibrate the mass scale for optimum mass accuracy.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
4 Symbols and abbreviated terms
4.1 Symbols
m mass of interest
m calibration mass 1
m calibration mass 2
M mass (u)
M peak centre (u)
ΔM mass accuracy (u)
M measured peak mass (u)
P
MT true mass (u)
U(m) mass uncertainty for a mass, m, arising from calibration
U uncertainty in the accurate mass measurement of m
1 1
U2 uncertainty in the accurate mass measurement of m2
U0 average uncertainty in an accurate mass measurement
V reflector or acceptance voltage (V)
R
W relative mass accuracy
x number of carbon atoms
y number of hydrogen atoms
G scaling term
α asymmetry term
σ(ΔM) standard deviation of the mass accuracy for a number of peaks
+
σ average of the standard deviations of ΔM for each of the four C H cascades with 4, 6, 7 and
M x y
8 carbon atoms
4.2 Abbreviated terms
MEMS micro-electromechanical system
PC polycarbonate
ppm parts per million
r/min revolutions per minute
SIMS secondary ion mass spectrometry
THF tetrahydrofuran
ToF time-of-flight
5 Outline of method
Here, the method is outlined so that the detailed procedure, given in Clause 6,6, can be understood in context.
First, to optimize a time-of-flight mass spectrometer using this procedure, obtain a thin film of polycarbonate
(PC) on a conducting substrate (silicon). The optimization procedure is achieved by carrying out the
procedures in 6.36.3 to 6.56.5 iteratively; it uses 19 specific CxHy peaks in the PC positive-ion mass spectrum.
In 6.6,In 6.6, a general calibration procedure is given which provides the rules by which calibrations for
inorganics and organics may be incorporated. This leads to a new generic set of ions for mass calibration that
can improve the mass accuracy from some often-used calibrations by a factor of five. The effects of
extrapolation beyond the calibration range are discussed and a recommended procedure is given to ensure
that accurate mass is achieved, within a selectable uncertainty, for large molecules. Therefore, the procedure
has two parts, optimization and calibration. Subclauses 6.1 to 6.56.1 to 6.5 are only required as part of the
regular maintenance of the instrument as defined by the testing laboratory. Subclause 6.66.6 is required for all
calibrations of the mass scale. This is summarized in the flowchart in Figure 1.Figure 1.
2 © ISO 2018 – All rights reserved
ISO/DISPRF 13084:2025(en)
Figure 1 — Flowchart of sequence of operations of the method
6 Method for improving mass accuracy
6.1 Obtaining the reference sample for optimization
A sample of thin (10 nm to 100 nm) PC on a flat conducting substrate (e.g. silicon wafer) shall either be
obtained or prepared, as described in 6.2.6.2.
6.2 Preparation of polycarbonate sample
6.2.1 6.2.1 Instructions for the preparation of a PC reference sample are provided. This method can give
[2]
[ ]
sample-to-sample repeatability in ToF SIMS spectra of better than 1,9 %. % 0 . To prepare such a sample for
static SIMS analysis requires a clean working environment. To reduce surface contamination, clean glassware,
tweezers and powderless gloves shall be used. The equipment required is a 1 ml glass pipette, a 100 ml glass-
stoppered measuring flask and a device for spin casting. If a device for spin casting is not available, droplet
deposition of the PC solution may be used. However, this will give poor repeatability, which will need to be
carefully taken into account during spectral analysis.
6.2.2 6.2.2 Using poly(bisphenol A carbonate), abbreviated to PC, weigh out 100 mg on a clean piece of
aluminium foil. Introduce the PC into the 100 ml, glass-stoppered measuring flask, add tetrahydrofuran (THF)
of analytical reagent quality to the 100 ml level line. Shake the flask to mix the PC and allow time to dissolve it
completely. This produces a 1 mg/ml solution of PC in THF. The aluminium foil shall be freshly unrolled and
4 © ISO 2018 – All rights reserved
ISO/DISPRF 13084:2025(en)
the shiny surface used. Ensure that the THF is anhydrous, otherwise streaks will appear from water when spin
coating, as described in 6.2.3.6.2.3. The shelf life of freshly prepared stock solution shall be no more than one
month owing to water take-up.
NOTE 1 It does not matter if the PC contains low levels of additives.
NOTE 2 It does not matter if the final PC/THF solution concentration varies by ±20 %.
6.2.3 6.2.3 Use a conveniently sized (1 cm by 1 cm) piece of silicon, or another flat or polished conducting
substrate, and clean it overnight by soaking in propan-2-ol (isopropyl alcohol). Ultrasonically clean the
substrate in fresh propan-2-ol and dry. If an ultrasonic bath is not available, just rinse the sample in fresh
propan-2-ol. Mount the substrate on the spin casting device. Pipette approximately 0,2 ml of the PC solution
onto the substrate and spin cast at 4 000 r/min for 25 s. Samples may be prepared by depositing the PC
solution using a 5 ml pipette onto the silicon surface then air drying under ambient conditions. However, this
method will result in an uneven PC film, so care shall be taken when comparing spectra, as peak intensities
will vary.
NOTE 1 It is not essential what substrate is used, as long as it is conducting. Silicon has been found to give good-quality
films.
NOTE 2 Using this procedure, the film thickness will be approximately 10 nm. The absolute thickness is not critical.
However, if it is too thick, it is possible that the optimal SIMS spectral data is not obtained due to the charge build up
(charging).
6.3 Obtaining the SIMS spectral data
6.3.1 6.3.1 Insert the PC sample inside the chamber of the SIMS instrument.
6.3.2 6.3.2 Operate the
...
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