EN ISO 14644-9:2022
(Main)Cleanrooms and associated controlled environments - Part 9: Assessment of surface cleanliness for particle concentration (ISO 14644-9:2022)
Cleanrooms and associated controlled environments - Part 9: Assessment of surface cleanliness for particle concentration (ISO 14644-9:2022)
This document establishes a procedure for the assessment of particle cleanliness levels on solid surfaces in cleanrooms and associated controlled environment applications. Recommendations on testing and measuring methods, as well as information about surface characteristics, are given in Annexes A to D.
This document applies to all solid surfaces in cleanrooms and associated controlled environments, such as walls, ceilings, floors, working environments, tools, equipment and products. The procedure for the assessment of surface cleanliness by particle concentration (SCP) is limited to particles of between 0,05 µm and 500 µm.
The following issues are not considered in this document:
— requirements for the cleanliness and suitability of surfaces for specific processes;
— procedures for the cleaning of surfaces;
— material characteristics;
— references to interactive bonding forces or generation processes that are usually time-dependent and process-dependent;
— selection and use of statistical methods for assessment and testing;
— other characteristics of particles, such as electrostatic charge, ionic charges and microbiological state.
Reinräume und zugehörige Reinraumbereiche - Teil 9: Bewertung der partikulären Oberflächenreinheit (ISO 14664‑9:2022)
Dieses Dokument beschreibt ein Verfahren für die Bewertung der partikulären Reinheitsgrade auf festen Oberflächen für Anwendungen in Reinräumen und zugehörigen Reinraumbereichen. Empfehlungen zu Prüf- und Messverfahren sowie Angaben zu Oberflächenkenngrößen sind in Anhang A bis Anhang D enthalten.
Dieses Dokument ist anzuwenden für alle festen Oberflächen in Reinräumen und zugehörigen Reinraumbereichen, wie z. B. Wände, Decken, Fußböden, Arbeitsbereiche, Werkzeuge, Ausrüstungsgegenstände und Produkte. Das Verfahren für die Bewertung der partikulären Oberflächenreinheit (SCP, en: surface cleanliness by particle concentration) ist auf Partikel zwischen 0,05 µm und 500 µm begrenzt.
Die folgenden Punkte werden in diesem Dokument nicht behandelt:
Anforderungen an die Reinheit und Eignung von Oberflächen für bestimmte Prozesse;
Verfahrensweisen für die Reinigung von Oberflächen;
Materialkenngrößen;
Bezüge auf die wechselseitigen Bindungskräfte oder Entstehungsprozesse, die üblicherweise zeitabhängig und prozessabhängig sind;
Auswahl und Anwendung statistischer Bewertungs- und Prüfverfahren;
weitere Kenngrößen von Partikeln, wie z. B. elektrostatische Ladung, Ionenladungen und mikrobiologischer Zustand.
Salles propres et environnements maîtrisés apparentés - Partie 9: Évaluation de la propreté des surfaces en fonction de la concentration de particules (ISO 14644-9:2022)
Le présent document établit un mode opératoire pour l’évaluation des niveaux de propreté particulaire des surfaces solides, applicables aux salles propres et aux environnements maîtrisés apparentés. Les Annexes A à D fournissent des recommandations relatives aux essais et aux méthodes de mesurage, ainsi que des informations sur les caractéristiques des surfaces.
Le présent document s’applique à toutes les surfaces solides dans les salles propres et environnements maîtrisés apparentés telles que les murs, les plafonds, les sols, les environnements de travail, les outils, les équipements et les produits. Le mode opératoire d’évaluation de la propreté des surfaces par la concentration de particules (SCP) se limite à des tailles de particules comprises entre 0,05 µm et 500 µm.
Le présent document n’aborde pas les points suivants:
— les exigences pour la propreté et l’adéquation des surfaces à des processus spécifiques;
— les modes opératoires de nettoyage des surfaces;
— les caractéristiques des matériaux;
— les références aux forces de liaison ou aux processus de génération qui sont généralement fonction du temps et qui dépendent du procédé;
— le choix et l’utilisation de méthodes statistiques pour l’évaluation et les essais;
— d’autres caractéristiques des particules, telles que la charge électrostatique, les charges ioniques et l’état microbiologique.
Čiste sobe in podobna nadzorovana okolja - 9. del: Ocenjevanje čistosti površine na osnovi koncentracije delcev (ISO 14644-9:2022)
Ta dokument določa postopek za ocenjevanje stopenj čistosti delcev na trdnih površinah v čistih sobah in podobnih nadzorovanih okoljih. V dodatkih od A do D so navedena priporočila za preskušanje, merilne metode ter informacije o značilnostih površine. Ta dokument se uporablja za vse trdne površine v čistih sobah in podobnih nadzorovanih okoljih, kot so stene, stropi, tla, delovna okolja, orodja, oprema in izdelki. Postopek ocenjevanja čistosti površine s koncentracijo delcev (SCP) je omejena na delce velikosti od 0,05 μm do 500 μm. V tem dokumentu niso zajeti naslednji elementi: – zahteve glede čistosti in primernosti površin za specifične postopke; – postopki čiščenja površin; – značilnosti materialov; – sklicevanja na interaktivne sile spajanja ali postopke nastajanja, ki so običajno odvisni od časa in postopka; – izbira in uporaba statističnih metod za ocenjevanje in preskušanje; – druge značilnosti delcev, na primer elektrostatični naboj, naboji ionov in mikrobiološko stanje.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2022
Nadomešča:
SIST EN ISO 14644-9:2012
Čiste sobe in podobna nadzorovana okolja - 9. del: Ocenjevanje čistosti površine
na osnovi koncentracije delcev (ISO 14644-9:2022)
Cleanrooms and associated controlled environments - Part 9: Assessment of surface
cleanliness for particle concentration (ISO 14644-9:2022)
Reinräume und zugehörige Reinraumbereiche - Teil 9: Klassifizierung der partikulären
Oberflächenreinheit (ISO 14644-9:2022)
Salles propres et environnements maîtrisés apparentés - Partie 9: Évaluation de la
propreté des surfaces en fonction de la concentration de particules (ISO 14644-9:2022)
Ta slovenski standard je istoveten z: EN ISO 14644-9:2022
ICS:
13.040.35 Brezprašni prostori in Cleanrooms and associated
povezana nadzorovana controlled environments
okolja
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 14644-9
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2022
EUROPÄISCHE NORM
ICS 13.040.35 Supersedes EN ISO 14644-9:2012
English Version
Cleanrooms and associated controlled environments - Part
9: Assessment of surface cleanliness for particle
concentration (ISO 14644-9:2022)
Salles propres et environnements maîtrisés apparentés Reinräume und zugehörige Reinraumbereiche - Teil 9:
- Partie 9: Évaluation de la propreté des surfaces en Klassifizierung der partikulären Oberflächenreinheit
fonction de la concentration de particules (ISO 14644- (ISO 14644-9:2022)
9:2022)
This European Standard was approved by CEN on 18 April 2022.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14644-9:2022 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 14644-9:2022) has been prepared by Technical Committee ISO/TC 209
"Cleanrooms and associated controlled environments" in collaboration with Technical Committee
CEN/TC 243 “Cleanroom technology” the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by November 2022, and conflicting national standards
shall be withdrawn at the latest by November 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 14644-9:2012.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 14644-9:2022 has been approved by CEN as EN ISO 14644-9:2022 without any
modification.
INTERNATIONAL ISO
STANDARD 14644-9
Second edition
2022-05
Cleanrooms and associated controlled
environments —
Part 9:
Assessment of surface cleanliness for
particle concentration
Salles propres et environnements maîtrisés apparentés —
Partie 9: Évaluation de la propreté des surfaces en fonction de la
concentration de particules
Reference number
ISO 14644-9:2022(E)
ISO 14644-9:2022(E)
© ISO 2022
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
ii
ISO 14644-9:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 The surface cleanliness level assessment system . 3
5.1 ISO-SCP grading level format . 3
5.2 Designation . 6
5.3 General information on surface cleanliness levels of particle concentration . 6
6 Demonstration of conformity .6
6.1 Principle . 6
6.2 Testing . 6
6.3 Test report . 7
Annex A (informative) Surface characteristics . 9
Annex B (informative) Descriptor for specific particle size ranges .12
Annex C (informative) Parameters influencing the SCP grading level assessments.15
Annex D (informative) Measurement methods for determining surface cleanliness by
particle concentration .17
Bibliography .26
iii
ISO 14644-9:2022(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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 209, Cleanrooms and associated controlled
environments, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 243, Cleanroom technology, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 14644-9:2012), of which it constitutes a
minor revision. The changes are as follows:
— "Class" (classification, classified) has been changed to grade or assessment where appropriate;
— ISO 14644-6 has been removed from the opening text of Clause 3 and, as a result, Clause 2;
— entry 3.8 removed from Clause 3;
— ISO 4287 and ISO 4288 replaced by ISO 21920-2 and ISO 21920-3, respectively;
— ISO 16232-2, ISO 16232-3, ISO 16232-4 and ISO 16232-5 replaced by ISO 16232;
— minor editorial changes.
A list of all parts in the ISO 14644 series can be found on the ISO website.
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.
iv
ISO 14644-9:2022(E)
Introduction
Cleanrooms and associated controlled environments provide for the control of contamination to levels
appropriate for accomplishing contamination-sensitive activities. Products and processes that benefit
from the control of contamination include those in such industries as aerospace, microelectronics,
optics, nuclear and life sciences (pharmaceuticals, medical devices, food, healthcare).
ISO 14644-1 to ISO 14644-8, ISO 14698-1 and ISO 14698-2 deal exclusively with airborne particle
and chemical contamination. Many factors, besides the assessment of surface cleanliness, should
be considered in the design, specification, operation and control of cleanrooms and other controlled
environments. These factors are covered in some detail in other parts of ISO 14644 and ISO 14698.
This document provides an analytical process for the determination and designation of surface
cleanliness levels based on particle concentration. This document also lists some methods of testing, as
well as procedure(s) for determining the concentration of particles on surfaces.
Where regulatory agencies impose supplementary guidelines or restrictions, appropriate adaptations
of the testing procedures might be required.
NOTE When assessment of surface cleanliness by particle concentration (SCP) at critical control point(s) is
used as an additional cleanliness attribute to classification of air cleanliness by airborne particle concentration
in accordance with ISO 14644-1, then the space can be described as a cleanroom or clean-zone. If SCP is used
alone, then the space is described as a controlled zone.
v
INTERNATIONAL STANDARD ISO 14644-9:2022(E)
Cleanrooms and associated controlled environments —
Part 9:
Assessment of surface cleanliness for particle
concentration
1 Scope
This document establishes a procedure for the assessment of particle cleanliness levels on solid surfaces
in cleanrooms and associated controlled environment applications. Recommendations on testing and
measuring methods, as well as information about surface characteristics, are given in Annexes A to D.
This document applies to all solid surfaces in cleanrooms and associated controlled environments, such
as walls, ceilings, floors, working environments, tools, equipment and products. The procedure for the
assessment of surface cleanliness by particle concentration (SCP) is limited to particles of between
0,05 µm and 500 µm.
The following issues are not considered in this document:
— requirements for the cleanliness and suitability of surfaces for specific processes;
— procedures for the cleaning of surfaces;
— material characteristics;
— references to interactive bonding forces or generation processes that are usually time-dependent
and process-dependent;
— selection and use of statistical methods for assessment and testing;
— other characteristics of particles, such as electrostatic charge, ionic charges and microbiological
state.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/
ISO 14644-9:2022(E)
3.1
descriptor for specific particle size ranges
differential descriptor that expresses surface cleanliness by particle concentration (SCP) level within
specific particle size ranges
Note 1 to entry: The descriptor may be applied to particle size ranges of special interest or those particle size
ranges that are outside the range of the grading system and specified independently or as a supplement to the
SCP levels.
3.2
direct measurement method
assessment of the contamination without any intermediate steps
3.3
indirect measurement method
assessment of the contamination with intermediate steps
3.4
solid surface
boundary between the solid and a second phase
3.5
surface particle
solid and/or liquid matter adhered and discretely distributed on a surface of interest, excluding film-
like matter that covers the whole surface
Note 1 to entry: Surface particles are adhered via chemical and/or physical interactions.
3.6
surface cleanliness by particle concentration
SCP
condition of a surface with respect to its particle concentration
Note 1 to entry: The surface cleanliness depends upon material and design characteristics, stress loads
(complexity of loads acting on a surface) and prevailing environmental conditions, along with other factors.
3.7
surface cleanliness by particle concentration level
SCP rating
grading number stating the maximum allowable surface concentration, in particles per square metre,
for a considered size of particles [surface cleanliness by particle concentration (SCP) grades 1 to 8],
where level 1 represents the cleanest level
3.8
surface particle concentration
number of individual particles per unit of surface area under consideration
4 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
AFM atomic force microscopy
CNC condensation nucleus counter
EDX energy dispersive X-ray spectroscopy
ESCA electron spectroscopy for chemical analysis
ESD electrostatic discharge
ISO 14644-9:2022(E)
IR infrared (absorption spectroscopy)
OPC optical particle counter
PET polyethylene terephthalate
SCP surface cleanliness by particle concentration
SEM scanning electron microscopy
UV ultraviolet (spectroscopy)
WDX wavelength-dispersive X-ray spectroscopy
5 The surface cleanliness level assessment system
5.1 ISO-SCP grading level format
The degree of SCP in a cleanroom or associated controlled environment shall be designated by a
cleanliness level grading number, N, specifying the maximum total particle concentration on surfaces
permitted for a considered particle size. N shall be determined from Formula (1) with the maximum
permitted total particle concentration on the surface, C , in particles per square metre of surface,
SCP;D
for each considered particle size, D:
N
Ck= (1)
SCP;D
D
where
C is the maximum permitted total surface concentration, in particles per square metre of
SCP;D
surface, of particles that are equal to or larger than the considered particle size; C is
SCP;D
rounded to the nearest whole number, using no more than three significant figures;
N is the SCP cleanliness level grading number, which is limited to SCP grade level 1 to SCP
grade level 8; the SCP grade level number N is qualified by the measured particle diameter
D, in micrometres;
NOTE N refers to the exponent base 10 for the concentration of particles at the reference
particle size of 1 µm.
D is the considered particle size, in micrometres;
k is a constant 1, in micrometres.
NOTE 1 The SCP grade level based on the particle concentration can be a time- and process-dependent value
due to the dynamic characteristics of particle generation and transportation.
NOTE 2 Due to the complexity of statistical evaluations and readily available additional references, the
selection and use of statistical methods for testing are not described in this document.
The concentration C , as derived from Formula (1), shall serve as the definitive value. Table 1
SCP;D
presents selected SCP grading levels and corresponding maximum cumulative permitted total surface
concentrations for considered particle sizes.
Figure 1 provides a representation of the selected surface particle grade levels in graphical form.
ISO 14644-9:2022(E)
Table 1 — Selected SCP grading levels for cleanrooms and associated controlled environments
Units in particles per square metre
Particle size
SCP level
≥ 0,05 µm ≥ 0,1 µm ≥ 0,5 µm ≥ 1 µm ≥ 5 µm ≥ 10 µm ≥ 50 µm ≥ 100 µm ≥ 500 µm
SCP level 1 (200) 100 20 (10)
SCP level 2 (2 000) 1 000 200 100 (20) (10)
SCP level 3 (20 000) 10 000 2 000 1 000 (200) (100)
SCP level 4 (200 000) 100 000 20 000 10 000 2 000 1 000 (200) (100)
SCP level 5 1 000 000 200 000 100 000 20 000 10 000 2 000 1 000 (200)
SCP level 6 (10 000 000) 2 000 000 1 000 000 200 000 100 000 20 000 10 000 2 000
SCP level 7 10 000 000 2 000 000 1 000 000 200 000 100 000 20 000
SCP level 8 10 000 000 2 000 000 1 000 000 200 000
The values in Table 1 are concentrations of particles of the related particle size and SCP level per surface area of one square metre
(1 m ) equal to or larger than the considered particle size (C ).
SCP;D
For figures in parentheses, the corresponding particle sizes should not be used for level determination purposes; select another
particle size for more accurate determination.
The minimum area for testing should be statistically representative of the surface under consideration.
NOTE Assessment of the lower SCP levels requires numerous measurements to establish a significant value.
ISO 14644-9:2022(E)
Key
X considered particle size, D (µm)
Y particle concentration on a surface ≥ D, C (particles/m )
SCP;D
1 SCP grade level 1
2 SCP grade level 2
3 SCP grade level 3
4 SCP grade level 4
5 SCP grade level 5
6 SCP grade level 6
7 SCP grade level 7
8 SCP grade level 8
The solid lines shown on the graph shall be used for level assessment purposes. The dashed lines should not be used
for level assessment purposes.
NOTE Particle distribution on surfaces typically is not a normal distribution, but is affected by different
factors, such as roughness, porosity, electrostatic charge and deposition mechanisms (see Annex A).
2 5
EXAMPLE SCP grade level 5 (1 µm) signifies that 1 m of surface may carry a maximum of 10 particles with
a considered particle size ≥ 1 µm (D = 1). SCP grade level 5 (10 µm) signifies that 1 m of surface may carry a
maximum of 10 particles per square metre with a considered particle size ≥ 10 µm (D = 10). Any other measured
particle size (D = x) which leads to a concentration that lies below the relevant SCP line is within the specification
of SCP grade level 5 (x µm).
Figure 1 — SCP grade levels
For particle sizes outside the limits of the level numbering system and in cases where only a narrow
particle range or individual particle sizes are of interest, a descriptor can be used (see Annex B).
ISO 14644-9:2022(E)
5.2 Designation
The SCP grade level number shall be formatted as follows: SCP grade level N (D µm).
The designation of the SCP grade for cleanrooms and associated controlled environments shall also
include the following:
a) the surface type measured;
b) the surface area measured;
c) the measurement method applied.
Details of measurement methods applied, including sampling techniques and measurement devices,
should be retrieved from test reports.
The considered particle size should be determined by agreement between the customer and supplier.
The SCP grade level shall be stated in relation to the measured particle size diameter.
EXAMPLE 1 SCP grade level 2 (0,1 µm); wafer or glass substrate, surface area: 310 cm ; surface particle
counter.
EXAMPLE 2 SCP grade level 5 (0,5 μm); inner wall of a bottle, surface area: 200 cm ; liquid dispersion — liquid
particle counter.
5.3 General information on surface cleanliness levels of particle concentration
Airborne particle concentration and surface particle concentration are generally related. The
relationship is dependent on many factors, such as airflow turbulence, rate of deposition, time of
deposition, deposition velocity, concentration within the air and surface characteristics such as
electrostatic charge (see A.2.4).
To determine SCP, various parameters (see Annex C) and surface characteristics (see Annex A) that
influence testing should be taken into account.
6 Demonstration of conformity
6.1 Principle
Conformity with SCP grade cleanliness level requirements, as specified by the customer, is verified by
performing tests and by providing documentation of the results and conditions of the testing.
Details for demonstrating conformity (see 6.3) shall be agreed upon between the customer and supplier
in advance of testing.
6.2 Testing
Tests performed to demonstrate conformity shall be conducted in a controlled environment using
suitable test methods and calibrated instruments, whenever possible.
Direct and indirect test methods can be used for demonstrating conformity and are given in Annex D.
The list of typical methods described is not exhaustive. Alternative methods of comparable accuracy
may be specified by agreement.
NOTE Measurement by different methods, even when correctly applied, can produce different results of
equal validity.
Repeated measurements are recommended.
The test method and environment shall be agreed upon between the customer and supplier.
ISO 14644-9:2022(E)
Precautions should be taken to reduce electrostatic charge around the test zone, since electrostatic
charge enhances particle deposition onto surfaces. If the surface is neither conductive, nor grounded
or charge-neutralized, electrostatic charges can occur (see Annex A). Therefore, test results can vary.
6.3 Test report
The results from testing each surface shall be recorded and submitted as a comprehensive report, along
with a statement of conformity or non-conformity with the specified SCP grade levels.
The test report shall include as a minimum the following:
a) basic data:
— date and time of testing;
— name and address of the testing organization;
— name of testing personnel;
b) references consulted:
— standards;
— guidelines;
— regulations;
— number and year of publication of this document, i.e. ISO 14644-9:2022;
c) environmental data:
— environmental conditions for sampling (i.e. temperature, humidity, cleanliness);
— environmental conditions for measurement (i.e. temperature, humidity, cleanliness) (not
essential for use with direct methods);
— location (e.g. room) used for the measurements;
d) specimen:
— clear identification of the test object;
— description of the test object;
— graph and/or sketch of the test specimen;
e) test setup:
— photo and/or sketch of the test setup;
— description of operating parameters;
— description of measurement points;
— description of hardware used in the test setup;
f) measurement devices:
— identification of the instrument(s) and measuring devices used and current calibration
certificate(s);
— measurement range of measuring devices used;
— reference of calibration certificates;
ISO 14644-9:2022(E)
g) performing the test:
— relevant details of the test procedure used, with any available data describing deviations from
the test procedure (if agreed);
— surface condition before sampling (e.g. after cleaning, after packaging, under atmospheric or
vacuum conditions);
— specified test and measurement procedure or method;
— occupancy state(s) during sampling and measurement;
— specified test method(s);
— all agreed documentation (e.g. raw data, background particle concentrations, pictures, graphs,
cleaning and packaging);
— duration, location and position of sampling (not essential for use with direct methods);
— duration, location and position of measurement (not essential for use with direct methods);
— noticeable observations made during sampling or measurement, where applicable;
— number of measurements performed;
— clear identification of the position and the area of the surface measured and specific designations
for coordinates of the surface, if applicable;
h) results and analysis:
— visual inspection of the test surface before and after measurement, where applicable;
— measurement values and/or their analysis;
— statement of data quality;
— particle size ranges considered;
— test results, including particle concentration data for given particle sizes, for all tests performed;
— SCP grading level with designation expressed as SCP cleanliness grade level N;
— acceptance criteria for the clean surface, if agreed between the customer and the supplier.
ISO 14644-9:2022(E)
Annex A
(informative)
Surface characteristics
A.1 Surface description
A surface is commonly characterized by its texture (such as roughness, porosity), its mechanical
properties (such as hardness) and its physicochemical properties (such as electrostatic surface charge
and surface tension). Each of these properties should be considered before selecting a test method for
the surface cleanliness assessment, or as an aid for the interpretation of the test results.
A.2 Surface characteristics
A.2.1 Roughness
A.2.1.1 Description
As the roughness of a surface affects many of its physical properties, surface roughness is not easily
described by one single parameter, nor is it an intrinsic property of the surface. Roughness exists in
two principal planes: at right angles to the surface, where it may be characterized by height, and in the
plane of the surface, identified as “texture” and characterized by waviness. The roughness of a surface
can be determined by mechanical or optical methods.
A.2.1.2 Testing
A frequently used mechanical method for the determination of roughness is the stylus instrument (see,
for example, ISO 21920-2 or ISO 21920-3).
Frequently used optical methods for the determination of roughness and porous texture are
microscopes (optical, confocal, interferometry, with or without tunnel effect, taper sectioning).
A.2.2 Porosity
A.2.2.1 Definition and description
Porosity is a measure of the void spaces in a material and is expressed as a decimal between 0 and 1, or
as a percentage between 0 % and 100 %.
— Effective porosity (also called open porosity) refers to the fraction of the total volume in which
fluid flow is effectively taking place (this excludes dead-end pores or non-connected cavities).
— Macroporosity refers to pores equal to or greater than 50 nm in diameter. Fluid flow through
macropores is described by bulk diffusion.
— Mesoporosity refers to pores equal to or greater than 2 nm but less than 50 nm in diameter.
— Microporosity refers to pores smaller than 2 nm in diameter. Movement in micropores is by
activated diffusion.
ISO 14644-9:2022(E)
A.2.2.2 Testing
There are several ways to estimate the porosity of a given material or mixture of materials, which is
called material matrix.
The volume/density method is fast and highly accurate (normally within ± 2 % of the actual porosity).
The volume and the weight of the material are measured. The weight of the material divided by the
density of the material gives the volume that the material takes up, minus the pore volume. Therefore,
the pore volume is simply equal to the total volume minus the material volume, i.e. (pore volume) = (total
volume) − (material volume).
The water saturation method is slightly more difficult but is more accurate and more direct. Take a
known volume of the material and a known volume of water. Slowly dump the material into the water
and allow it to saturate while pouring. Allow it to sit for a few hours to ensure that the material is fully
saturated. Then remove the unsaturated water from the top of the beaker and measure its volume.
The total volume of the water originally in the beaker minus the volume of water not saturated is the
volume of the pore space, i.e. (pore volume) = (total volume of water) − (unsaturated water).
Mercury intrusion porosimetry requires the sample to be placed in a special filling device that allows
the sample to be evacuated, followed by the introduction of liquid mercury. The size of the mercury
envelope is then measured as a function of increased applied pressure. The greater the applied pressure,
the smaller the pore entered by mercury. Typically, this method is used over the range of pores from
300 µm to 0,0 035 µm. Because of increased safety concerns over the use of mercury, several non-
mercury intrusion techniques have been developed and should be considered as alternatives.
Nitrogen gas adsorption is used to determine fine porosity in materials. In very small pores, nitrogen
gas condenses on pore walls that are less than 0,090 µm in diameter. This condensation is measured
either by volume or weight.
A.2.3 Hardness
There are many National and International Standards on hardness tests for each material type.
Hardness is frequently measured by the penetrating force of a diamond ball or tip, by the indentation of
a hard body or by the rebound properties of an impactor.
The Rockwell, Brinell, Shore and Vickers method for metals is covered by ASTM E18-07. Geometry
and pressure are chosen at the beginning of the test as a function of the thickness of the sample, the
composition of the metal and the supposed hardness.
A.2.4 Static electricity
A.2.4.1 Definition and description
Static electricity is defined as an electrical charge caused by an imbalance of electrons on the surface
of a material. This imbalance of electrons produces an electrostatic field that can influence the
determination of the surface cleanliness of objects. ESD is defined as the transfer of charge between
bodies at different electrical potentials.
Any relative motion and physical separation of materials or flow of solids, liquids or particle-laden
gases can generate electrostatic charges. Common sources of ESD include personnel, items made from
common polymeric materials and processing equipment. ESD can damage parts by direct contact with
a charged source or by electric fields emanating from charged objects.
Charged surfaces can attract and hold particle contaminants. If the selected measurement method
to determine the surface cleanliness is based on an indirect detection of particles on surfaces (see
D.2.3.3.5), these measurement results might be inaccurate, as the particle removal is diminished.
Therefore, especially when using indirect measurement methods, action should be taken to reduce ESD
effects.
ISO 14644-9:2022(E)
A.2.4.2 Testing
Determination of the ESD properties of the specimen surfaces can be helpful in estimating the influence
of the removal efficiency of particles from surfaces (e.g. IEC 61340-5-1, ISO 10015, IEST RP-CC022.2,
SEMI E43-0301, SEMI E78-0706).
A.2.5 Superficial tension
A.2.5.1 Definition
Superficial tension is the energy necessary to increase the surface by one area unit. It is usually defined
as γ and expressed in joules per square metre (J/m ) or in newtons per metre (N/m).
A.2.5.2 Testing
The best-known method is the measurement of the contact angle by the “set drop”, see Reference [19].
When a drop of liquid is brought into contact with a flat solid surface, its shape depends on the molecular
force within the liquid for cohesive force, or between the liquid and solid for adhesive force. The contact
angle between the liquid and solid is used as the surface tension index (see Figure A.1). It is generally
found that liquids with low surface tension easily wet most solid surfaces, giving a zero-contact angle.
The molecular adhesion between solid and liquid is greater than the cohesion between the molecules of
the liquid.
The contact angle measurement is performed with an optical method (× 10 to × 50) magnifying the
drop profile set on the flat solid surface.
Key
1 gas
2 liquid
3 solid
Figure A.1 — Shape of a drop of liquid in contact with a solid surface when the contact angle is
θ < 90°
ISO 14644-9:2022(E)
Annex B
(informative)
Descriptor for specific particle size ranges
B.1 Application
For particle sizes outside the range of the cleanliness level grading system, a differential descriptor can
be used. This descriptor can also be used for specific particle size ranges that are of special interest. In
these cases, the descriptor can be used in addition to the SCP grade levels.
B.2 Surface descriptor for specific particle size ranges
The N (particle number concentration of a specific particle size range) descriptor for specific particle
ss
size ranges may be specified independently or as a supplement to the SCP grading levels. The descriptor
can be applied to any particle size range of special interest.
The surface particle concentration C within the particle size range D and D is a differential value.
s L U
The N for a single particle size range is expressed according to Formula (B.1):
ss
NC();;DD ab; (B.1)
ss sL U
where
C is the maximum permitted total surface concentration, in particles per square metre of surface,
s
of the specified particle size range;
D is the lower limit of the specified particle size range, in micrometres;
L
D is the upper limit of the specified particle size range, in micrometres;
U
a is the measurement method used to determine particle size in the specified range;
b is the considered surface.
EXAMPLE 1 For the particle concentration on a metallic surface in the particle size range of 1 μm to 5 μm, the
2 2
required value is 10 000 particles/m (1,0 particles/cm ). The particle concentration is measured by an optical
microscope. The designation is:
N ()1000015;; opticalmicroscope;metallicsurface
ss
If two or more size ranges are used, apply Formula (B.2). N is then expressed in the format:
ss
CD;; D ab;
s1 L1 U1 1
CD;; D ab;
s2 L2 U2 2
N . . (B.2)
ss
CD;; D ab;
sLii Ui i
... ...
ISO 14644-9:2022(E)
where
C is the maximum permitted total surface concentration, in particles per square metre of surface,
si
of the i-th particle size range;
D is the lower limit of the i-th particle size range, in micrometres;
Li
D is the upper limit of the i-th particle size range, in micrometres;
Ui
a is the measurement method used to determine particle size in the i-th range;
i
b is the considered surface.
EXAMPLE 2 For the particle concentration on a glass plate, based on the simultaneous use of a scattered-light
scanner in the particle size range of 0,1 μm to 0,5 μm, and an optical microscope in the particle size range of 5 μm
2 2 2
to 20 μm, the measured values are 9 000 particles/m (0,9 particles/cm ) and 500 particles/m (0,05 particles/
2 2
cm ), respectively. The values are within the maximum allowable limits of 10 000 particles/m and 500 particles/
m , respectively. The designation is:
scattered light scanner; glasss plate
10 000;,01;,05
N
ss ( )
500;;520
optical microscope; glass plate
When measurement methods and/or specific surfaces are not predefined or are not essential,
designations a and b can be omitted. In this case, the descriptor is expressed according to Formula (B.3):
NC();;DD (B.3)
ss sL U
where
C is the maximum permitted total surface concentration, in particles per square metre of surface,
s
of the specified particle size range;
D is the lower limit of the specified particle size range, in micrometres;
L
D is the upper limit of the specified particle size range, in micrometres.
U
Where only one particle size is of interest, the lower and upper limit in Formula (B.3) can be used to
frame the particle size of interest through an agreement between the customer and supplier.
2 2
EXAMPLE 3 For the particle size 5 μm, the required value is 200 particles/m (0,02 particles/cm ). D can be
L
set to 4,5 μm and D can be set to 5,5 μm. The designation is:
U
N ()200;,45;,55
ss
When measurement methods and/or specific surfaces are not predefined or are not essential,
designations a and b can be omitted. The descriptor for two or more particle size ranges is expressed
according to Formula (B.4):
CD;; D
sL1 1U1
CD;; D
sL2 2U2
N . (B.4)
ss
CD;; D
sLii Ui
...
EXAMPLE 4 For the particle concentration in the particle size ranges of 0,1 μm to 0,5 μm and 5 μm to 20 μm,
2 2 2 2
the measured values are 9 000 particles/m (0,9 particles/cm ) and 500 particles/m (0,05 particles/cm ),
2 2
respectively. They are within the maximum allowable limits of 10 000 particles/m and 500 particles/m ,
respectively. The designation is:
ISO 14644-9:2022(E)
10000;,01;,05
N
ss
500;;520
ISO 14644-9:2022(E)
Annex C
(informative)
Parameters influencing the SCP grading level assessments
C.1 Background
Parameters that can influence the testing and measuring of surfaces are presented in C.2. The
information is not exhaustive and there is no ranking. More detailed information on measurement
methods and surface characteristics is given in Annex D.
C.2 Parameters
C.2.1 Physical or chemical properties
— Surface energy states. The attraction and removal of particles might be influenced, for example, by
cohesive or adhesive characteristics and/or hydrophilic or hydrophobic properties of the surface.
— Porosity of the surface. In most cases, the higher the degree of porosity, the more complex the
distinction between surface imperfection and particle detection.
— Cleanability of the surface. When surfaces are difficult to clean, the discrimination between
surface imperfection and particle detection is complex.
— Optical characteristics of the surface. When direct test methods are applied, different optical
characteristics of the surface to be tested will lead to different measurement results. This difference
is not noted for indirect methods.
— Electrostatic properties of the surface. The electrostatic properties of the surface will influence
the attraction and removal of ESD-charged contamina
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...