SIST EN 16602-70-50:2015

Space product assurance - Particles contamination monitoring for spacecraft systems and cleanrooms

This standard defines the requirements and guidelines for the measurement of particulate contamination on the surfaces of spacecraft systems and those of the cleanrooms or other cleanliness controlled areas in which they reside.
This includes the measurement of particulate contamination that is present on the spacecraft or cleanroom surfaces via the use of representative witness samples placed in the vicinity of the spacecraft hardware, the direct measurement of particulate contamination
levels on surfaces of spacecraft hardware from the direct surface transfer to adhesive tape-lift samples and particulate contaminant levels within fluids used for the cleaning or rinsing of such spacecraft system components and cleanroom surfaces. This standard also defines the methods to be used for the visual inspection of spacecraft system hardware for particulate contamination.
The measurement of airborne particulate contamination is not covered in this standard and ISO 14644 “Cleanrooms and associated
controlled environments” is applicable in this case.
This standard does not cover particulate contamination monitoring for spacecraft propulsion hardware which is covered in ECSS-E-ST-35-06.
This standard may be tailored for the specific characteristic and constrains of a space project in conformance with ECSS-S-ST-00.

Raumfahrtproduktsicherung - Überwachung der Teilchenkontamination von Raumfahrzeugsystemen und Reinräumen

Assurance produit des projets spatiaux - Surveillance de la contamination aux particules des systèmes orbitaux et des salles blanches

Zagotavljanje varnih proizvodov v vesoljski tehniki - Nadzorovanje onesnaženja z delci v sistemih vesoljskega plovila in čistih prostorih

Ta standard določa zahteve in smernice za merjenje onesnaženja z delci na površinah sistemov vesoljskega plovila in površinah čistih prostorov ali drugih območij z nadzorom čistoče, v katerih bivajo. Sem spada merjenje onesnaženja z delci, ki je prisotno na površinah vesoljskega plovila ali čistih prostorov, z uporabo reprezentativnih vzorcev v bližini strojne opreme vesoljskega plovila, neposredno merjenje ravni onesnaženja z delci na površinah strojne opreme vesoljskega plovila z neposrednega prenosa s površin na vzorce, zbrane z adhezivnim trakom, in ravni onesnaženja z delci v tekočinah, ki se uporabljajo za čiščenje ali splakovanje teh komponent sistemov vesoljskega plovila in površin čistih prostorov. Ta standard določa tudi metode, ki se uporabljajo za vizualni pregled strojne opreme sistemov vesoljskega plovila za onesnaženje z delci. Merjenje onesnaženja z delci v zraku ni obravnavano v tem standardu; v tem primeru se uporablja standard ISO 14644 »Čiste sobe in podobna nadzorovana okolja«. Ta standard ne obravnava nadzorovanja onesnaženja z delci za pogonsko strojno opremo vesoljskega plovila, kar je obravnavano v standardu ECSS-E-ST-35-06. Ta standard se lahko prilagodi posameznim lastnostim in omejitvam vesoljskega projekta v skladu s standardom ECSS-S-ST-00

General Information

• Status: Published
• Public Enquiry End Date: 19-Aug-2014
• Publication Date: 04-Mar-2015
• ICS: 13.040.35 - Cleanrooms and associated controlled environments
• ICS: 49.140 - Space systems and operations
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 19-Feb-2015
• Due Date: 26-Apr-2015
• Completion Date: 05-Mar-2015
• Mandate: M/496 - Mandate addressed to CEN, CENELEC and ETSI to develop standardisation regarding space industry (Phase 3 of the process)
• Ref Project: EN 16602-70-50:2015 - Space product assurance - Particles contamination monitoring for spacecraft systems and cleanrooms

Overview

EN 16602-70-50:2015 (CEN) - "Space product assurance - Particles contamination monitoring for spacecraft systems and cleanrooms" defines requirements and guidelines for measuring particulate contamination on spacecraft surfaces and on surfaces in the cleanrooms or controlled environments where spacecraft are built, integrated and tested. The standard covers representative witness samples, direct surface transfer techniques (e.g., tape‑lift), direct deposition to silicon wafers, rinsing and fluid sampling, microscope and automatic particle counting, particle fallout (PFO) sensors and methods for visual inspection. Airborne particle measurement is excluded (see ISO 14644), and propulsion hardware monitoring is handled separately (ECSS‑E‑ST‑35‑06).

Key Topics and Requirements

• Sampling methods: witness samples, tape‑lift, silicon wafer deposition, direct/indirect rinsing, filtered liquid and gas sampling.
• Particle counting & analysis: microscope counting procedures, automatic counters, background count measurement and subtraction, statistical sampling and conversion to obscuration factor.
• Particle fallout (PFO): sensor preparation, cleaning, packing, transportation, exposure and placement rules.
• Visual inspection: procedures for in‑situ and small items, lighting, magnification and inspector training.
• Quality assurance: record keeping, reporting formats, acceptance criteria, nonconformance control and tailoring of requirements to project needs.
• Terminology & definitions: background count, obscuration factor, effective sample area, cleanliness requirement specification, representative/tape‑lift samples.

The standard emphasizes reproducibility, precision, and controlled measurement environments (cleanliness controlled area) and provides normative annexes (requests, work proposals, and reporting templates).

Applications and Who Uses It

EN 16602-70-50 is used by:

• Spacecraft manufacturers and integrators for cleanliness verification during assembly, integration and test (AIT).
• Contamination control engineers and cleanroom managers to define sampling plans, PFO placements and inspection regimes.
• Quality assurance teams to establish acceptance criteria, reporting and nonconformance handling.
• Test laboratories and suppliers providing contamination monitoring services or furnishing witness samples and analytical results.

Practical applications include qualification of hardware prior to launch, verification after cleaning processes (rinsing/ultrasonic cleaning), monitoring of critical optical/electrical surfaces, and routine cleanroom surveillance tailored to a project’s contamination requirements.

Related Standards (if applicable)

• ISO 14644 - Cleanrooms and associated controlled environments (airborne particle measurement).
• ECSS‑E‑ST‑35‑06 - Propulsion hardware contamination (exclusion).
• ECSS‑Q‑ST‑70‑01 / EN 16602‑70‑01 - Cleanliness and contamination control (related space QA).
• ECSS‑S‑ST‑00 - Tailoring rules for space projects.
• ISO 14952‑3 - Surface cleanliness of fluid systems (analytical procedures).

Keywords: particulate contamination monitoring, spacecraft systems, cleanrooms, tape‑lift, silicon wafers, particle counting, particle fallout, cleanliness verification, contamination control.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2015
=DJRWDYOMDQMHYDUQLKSURL]YRGRYYYHVROMVNLWHKQLNL1DG]RURYDQMHRQHVQDåHQMD]
GHOFLYVLVWHPLKYHVROMVNHJDSORYLODLQþLVWLKSURVWRULK
Space product assurance - Particles contamination monitoring for spacecraft systems
and cleanrooms
Raumfahrtproduktsicherung - Überwachung der Teilchenkontamination von
Raumfahrzeugsystemen und Reinräumen
Assurance produit des projets spatiaux - Surveillance de la contamination aux particules
des systèmes orbitaux et des salles blanches
Ta slovenski standard je istoveten z: EN 16602-70-50:2015
ICS:
13.040.35 Brezprašni prostori in Cleanrooms and associated
povezana nadzorovana controlled environments
okolja
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 16602-70-50
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2015
ICS 49.140
English version
Space product assurance - Particles contamination monitoring
for spacecraft systems and cleanrooms
Assurance produit des projets spatiaux - Surveillance de la Raumfahrtproduktsicherung - Überwachung der
contamination aux particules des systèmes orbitaux et des Teilchenkontamination von Raumfahrzeugsystemen und
salles blanches Reinräumen
This European Standard was approved by CEN on 25 October 2014.

CEN and CENELEC 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 and CENELEC
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 and CENELEC member into its own language and notified to the CEN-CENELEC Management Centre
has the same status as the official versions.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Avenue Marnix 17, B-1000 Brussels
© 2015 CEN/CENELEC All rights of exploitation in any form and by any means reserved Ref. No. EN 16602-70-50:2015 E
worldwide for CEN national Members and for CENELEC
Members.
Table of contents
Foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 8
3.1 Terms defined in other standards . 8
3.2 Terms specific to the present standard . 8
3.3 Abbreviated terms. 11
4 Particulate cleanliness monitoring requirements . 12
4.1 Cleanliness requirement specification overview . 12
4.2 Cleanliness and contamination control plan . 12
5 Quantitative method requirements . 13
5.1 Particles sampling from surfaces . 13
5.1.1 Tape lift method . 13
5.1.2 Direct deposition on silicon wafers . 16
5.1.3 Rinsing (direct or indirect) . 18
5.2 Volume sampling . 21
5.2.1 Particles sampling from filtered liquid samples . 21
5.2.2 Particles sampling from filtered gas samples. 23
5.2.3 Particles sampling with automatic counters . 25
5.3 Particles counting with microscope . 25
5.3.1 Introduction . 25
5.3.2 General requirements . 25
5.3.3 Apparatus . 26
5.3.4 Method . 26
5.3.5 Statistical sampling method . 27
5.3.6 Conversion of particle count to obscuration factor . 29
5.4 Particle fallout measurement (PFO) . 30
5.4.1 Introduction . 30
5.4.2 General requirements . 30
5.4.3 Apparatus . 30
5.4.4 Cleaning of the sensors . 31
5.4.5 Packing of PFO sensors. 31
5.4.6 Transportation of PFO sensors . 31
5.4.7 Exposure of PFO sensors . 32
5.4.8 Location of the PFO sensors . 32
5.4.9 Fixation of the PFO sensors . 33
6 Visual inspection method requirements. 34
6.1 Introduction . 34
6.2 General requirements . 34
6.3 Visual inspection of small items . 35
6.3.1 Visual inspection of small contamination sensitive items . 35
6.3.2 Visual inspection of small non sensitive contamination items . 37
6.4 In situ visual inspection of spacecraft . 38
6.4.1 Introduction . 38
6.4.2 Apparatus . 38
6.4.3 Method . 38
7 Quality assurance . 39
7.1 Records . 39
7.2 Report . 39
7.3 Acceptance criteria and nonconformance . 39
Annex A (normative) Request for particle contamination monitoring - DRD . 41
Annex B (normative) Particulate contamination monitoring procedure
(Work proposal) - DRD . 42
Annex C (normative) Report on particle contamination monitoring - DRD . 44
Annex D (normative) Report on visual inspection - DRD . 47
Bibliography . 50

Figures
Figure 5-1: Schematic for vacuum filtering apparatus . 23
Figure 5-2: Gas sampling schematics . 25
Figure 5-3: Mask example for statistical sampling . 28

Tables
Table 5-1: Ranges and average areas for a single particle in each range . 30

Foreword
This document (EN 16602-70-50:2015) has been prepared by Technical
Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN.
This standard (EN 16602-70-50:2015) originates from ECSS-Q-ST-70-50C.
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 July 2015,
and conflicting national standards shall be withdrawn at the latest by July 2015.
Attention is drawn to the possibility that some of the elements of this document
may be the subject of patent rights. CEN [and/or CENELEC] shall not be held
responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CEN by the
European Commission and the European Free Trade Association.
This document has been developed to cover specifically space systems and has
therefore precedence over any EN covering the same scope but with a wider
domain of applicability (e.g. : aerospace).
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, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Introduction
Particulate contaminants can be hazardous to spacecraft in a number of ways
including failure of precision mechanisms, light absorption and scattering,
points of high local electric field and associated electrostatic discharge, and
noise on electrical contacts. It is therefore important to control, measure and
verify the particulate contamination levels on spacecraft systems and the
environments in which they reside, in order that an assessment can be made on
any hazards that may be present as a result of such contamination.
The objective of this standard is to ensure that the particle monitoring of
spacecraft systems and cleanrooms utilised in the production of such systems,
is carried out in an appropriate manner, and is controlled both in terms of the
precision of the measurements and the reproducibility of such measurements.
Scope
This standard defines the requirements and guidelines for the measurement of
particulate contamination on the surfaces of spacecraft systems and those of the
cleanrooms or other cleanliness controlled areas in which they reside.
This includes the measurement of particulate contamination that is present on
the spacecraft or cleanroom surfaces via the use of representative witness
samples placed in the vicinity of the spacecraft hardware, the direct
measurement of particulate contamination levels on surfaces of spacecraft
hardware from the direct surface transfer to adhesive tape-lift samples and
particulate contaminant levels within fluids used for the cleaning or rinsing of
such spacecraft system components and cleanroom surfaces. This standard also
defines the methods to be used for the visual inspection of spacecraft system
hardware for particulate contamination.
The measurement of airborne particulate contamination is not covered in this
standard and ISO 14644 “Cleanrooms and associated controlled environments”
is applicable in this case.
This standard does not cover particulate contamination monitoring for
spacecraft propulsion hardware which is covered in ECSS-E-ST-35-06.
This standard may be tailored for the specific characteristic and constrains of a
space project in conformance with ECSS-S-ST-00.
Normative references
The following normative documents contain provisions which, through
reference in this text, constitute provisions of this ECSS Standard. For dated
references, subsequent amendments to, or revision of any of these publications
do not apply. However, parties to agreements based on this ECSS Standard are
encouraged to investigate the possibility of applying the more recent editions of
the normative documents indicated below. For undated references, the latest
edition of the publication referred to applies.

EN reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS System - Glossary of terms
EN 16602-10-09 ECSS-Q-ST-10-09 Space product assurance - Nonconformance control
system
EN 16602-20 ECSS-Q-ST-20 Space product assurance - Quality assurance
EN 16602-70-01 ECSS-Q-ST-70-01 Space product assurance - Cleanliness and
contamination control
ISO 14952-3 Space systems - Surface cleanliness of fluid systems -
Part 3: Analytical procedures for the determination of
nonvolatile residues and particulate contamination

Terms, definitions and abbreviated terms
3.1 Terms defined in other standards
For the purpose of this Standard, the terms and definitions from ECSS-S-ST-00-01
apply.
3.2 Terms specific to the present standard
3.2.1 background count
measurement of the contamination levels produced by the measurement
method (and associated apparatus) and the measurement environment as
distinct from the inherent contamination level of the item to be measured
3.2.2 background subtraction
act of subtracting a background count from a measurement
3.2.3 black light illumination
illumination which predominantly produces light in the near UV region (310 nm
to 400 nm)
3.2.4 bubble
volume of trapped gas encapsulated by another medium
3.2.5 cleanliness and contamination control plan
plan which defines the organized actions to control the level of contamination
3.2.6 cleanliness controlled area
area in which there are specific measures to control and monitor contamination
which allows the counting of particles to be performed with sufficient accuracy
as defined by the background count
3.2.7 cleanliness requirement specification
specification that defines the requirement for allowable contamination levels
3.2.8 cleanliness verification
activity intended to verify that the actual cleanliness conditions of the
spacecraft system, the cleanrooms, and other environments in which the
spacecraft system will reside, are in conformance with the applicable
specifications and other cleanliness requirements
3.2.9 compatible
not deteriorating the functionality, performance and integrity of any item or
surface
3.2.10 contamination potential
potential amount of contaminant in the source which can produce
contamination defined in terms of the obscuration factor per unit time
NOTE The obscuration factor per unit time can be
2 2
expressed in [(mm /m )/h].
3.2.11 contamination sensitive
article which, if exposed to contamination, can be adversely affected in terms of
its designed function
3.2.12 effective sample area
area on a surface that has been exposed to a contamination source
3.2.13 lint-free
resistant to fibre generation
3.2.14 membrane filter
polymer film with specific pore sizes, designed to separate particles from
liquids or gases
3.2.15 non-shedding
resistant to particle generation
3.2.16 obscuration factor
ratio of the projected area of all particles to the total surface area on which they
rest
3.2.17 particle
unit of matter with observable length, width and thickness
NOTE For the purposes of this standard the particles
have typical dimensions of 0,1 μm to 1000 μm.
3.2.18 particulate contamination
airborne or surface contamination relating to particles
3.2.19 particle fallout
accumulated deposit of particulate matter on a surface
3.2.20 representative sample
sample which is designed to be the same as another item, either in physical
form or the environment in which it resides, or both
3.2.21 ripple
topographical in-homogeneity usually in the form of a wave pattern
3.2.22 sensitive surface
surface that has a high probability of damage
3.2.23 spectral grade
measure of solvent purity determined from its absorption spectrum
NOTE Typically spectral grade solvents have a purity
of greater than 99,5 %.
3.2.24 tape-lift
method of transferring particulate contamination from a surface with an
adhesive tape
3.2.25 tape-lift sample
length of transparent adhesive tape that has been used for a tape lift and
subsequently applied to a clean substrate to encapsulate any contamination
3.2.26 trained inspector
inspector certified by a third party certification body, or with proven on the job
experience that is agreed with or recognized by the customer
3.2.27 ultrasonic bath
bath containing liquid and a transducer which produces ultrasonic waves
which produce microscopic cavitation bubbles in the liquid which aids in the
removal of particles from surfaces of an item placed in the liquid
NOTE Typical frequency of ultrasonic waves is from
15 kHz to 400 kHz.
3.2.28 visibly clean
absence of surface contamination when examined with a specific light source,
angle of incidence and viewing distance using normal or magnified vision
NOTE 1 Different inspection methods are available,
depending on:
• hardware to be inspected, in term of size
and accessibility and sensitivity to
contamination
• inspection distance
• light spectra (including UV), intensities and
angles
NOTE 2 The “visibly clean” level roughly corresponds to
2 2
an obscuration factor smaller than 300 mm /m
when inspected from a distance of 30 cm to 60
cm with an oblique white light of 540 lx to 1620
lx.
NOTE 3 Typical magnification levels range from 2x to 8x.
3.2.29 visibly clean standard
absence of surface contamination when examined under oblique white light of
more than 540 lx and from a distance of 150 cm to 300 cm using normal vision
3.2.30 visibly clean sensitive
absence of surface contamination when examined under oblique white light of
more than 540 lx and from a distance of 60 cm to 120 cm using normal vision
3.2.31 visibly clean highly sensitive
absence of surface contamination when examined under oblique white light of
more than 1080 lx and from a distance of 15 cm to 45 cm using normal or
magnified vision
3.2.32 visual inspection
act of examining an object under defined illumination and viewing conditions
with normal or magnified vision
3.2.33 void
area devoid of matter
3.3 Abbreviated terms
The following abbreviations are defined and used within this standard:
Abbreviation Meaning
cleanliness and contamination control plan
C&CCP
cleanliness requirement specification
CRS
isopropyl alcohol
IPA
International Organization for Standardization
ISO
laser emitting diode
LED
lux
lx
obscuration factor
OF
printed circuit board
PCB
particle fallout
PFO
ultra-violet
UV
ultra-violet (310 nm - 400 nm)
UVA
Particulate cleanliness monitoring
requirements
4.1 Cleanliness requirement specification overview
ECSS-Q-ST-70-01 requires that the particulate contamination level applicable to
spacecraft systems is defined in a cleanliness requirement specification (CRS).
This standard also requires that the CRS explicitly defines the allowable levels
of particulate contamination throughout the lifetime of the spacecraft, and that
this levels are incorporated into the overall cleanliness budget for the spacecraft
systems.
4.2 Cleanliness and contamination control plan
a. Particulate cleanliness and contamination control shall be planned in
accordance with ECSS-Q-ST-70-01.
NOTE Cleanliness and Contamination Control Plan
(C&CCP) identifies potential contamination
sources, the effects that those sources have on
the spacecraft systems in addition to identifying
spacecraft systems which are contamination
sensitive to particles.
b. Measurement methods specified in 5.1, 5.2 and 5.4 shall be employed in
order to monitor and report particulate contamination levels.
Quantitative method requirements
5.1 Particles sampling from surfaces
5.1.1 Tape lift method
5.1.1.1 Introduction
This clause describes the tape-lift method to be used for the sampling of
surfaces for the purpose of the determining particulate contamination levels,
and the definition of the particle size distribution. In this case, the surface
particulate is analysed using a direct transfer method, whereby a transparent
adhesive tape is applied to the surface to be tested and the particles are
transferred from the sample surface to the adhesive tape. The particles
transferred to the tape are then analysed using an optical microscope.
An ASTM standard also exists, ASTM E 1216-06, Standard practice for sampling
for particulate contamination by tape-lift.
5.1.1.2 General requirements
a. Any counting of particles for the purpose of determining particulate
contamination levels using the tape lift method shall be performed in a
cleanliness controlled area.
b. Sensitive surfaces shall not be analysed using the tape lift method.
c. In the case where adhesive residue is removed from the surface subjected
to the tape-lift test, the potential damage that can be caused by the
cleaning of the surface shall be assessed prior to conducting the tape-lift
test.
d. If the sensitivity of the surface to be tested is not known, the tape lift
method shall not be used unless a trial tape-lift has been conducted on a
representative sample with the same surface and shows the surface not to
be a sensitive surface.
e. The application of force on contaminant particles, present on the surface,
during the performing of the tape-lift test shall not damage the sampled
surface.
f. In the case of surfaces described in 5.1.1.2b, a non-sensitive surface that
has been subject to the same environmental conditions and is
representative of the sensitive surface, shall be used in place of the
sensitive surface.
5.1.1.3 Apparatus
a. The following apparatus shall be used to perform a tape-lift analysis:
1. A low-tack, transparent adhesive tape with an adhesive force of
less than 0,3 N/mm.
2. A tape that is free of particles, voids, bubbles, and other artefacts
detrimental to the counting of particles.
3. A membrane filter with a pore size less than 1 µm, and a minimum
diameter of 5 cm, which provides contrast with the particulate
contaminants being analyzed.
NOTE The choice of the membrane filter depends
upon the nature of the particles being analysed
(e.g. a white membrane filter in the case of
black particles and a black membrane filter in
the case of white particles). Membrane filters
can have grids when statistical counting is
used.
4. A mask or gridded membrane filter to perform statistical counting
on squares of pre-defined area.
5. Non-shedding and lint-free gloves.
6. Tweezers.
7. Scissors or a scalpel.
8. A clean container for the transport of the tape-lift sample to the
measurement facility.
NOTE 1 A clean container is a container devoid of
particulate that could influence the
measurement of the tape-lift sample.
NOTE 2 The container can be sealed to prevent external
contamination from reaching the internal parts
of the container.
5.1.1.4 Tape-lift method
a. Application of the adhesive tape to the surface to be analysed shall be
performed as follows:
1. Remove with a velocity not exceeding 1 cm/s a minimum of 6 cm
to 10 cm of the low tack, transparent adhesive tape from the tape
roll.
NOTE The reason to remove the tape slowly from the
roll is to minimise static electricity.
2. For small surfaces (< 5 cm dimension), if a tape-lift measurement is
performed to determine the local particulate contaminant levels,
the dimensions of both the total surface and the surface analysed
are recorded in the measurement report.
3. Once removed from the roll, the tape is immediately applied to the
sample surface in one direction by the application of a force of less
than 0,1 N, using one gloved finger, or a folded lint-free tissue, to
smooth the tape on the sample surface.
b. The applied tape shall have uniform adhesion to the surface, i.e. free of
voids, bubbles and un-adhered areas.
c. If the tape, as applied on the sample surface, is not uniformly adhered, or
shows the presence of ripple or bubbles, it shall be rejected and a new
sample taken in a different location.
d. The removal of the adhesive tape from the surface to be analysed shall be
conducted as follows:
1. Approximately 5 cm of tape are removed from the surface being
analysed using a constant speed of less than 1 cm/s, at
approximately 45 degrees to the sample surface.
2. Sudden or uneven forces are not used.
e. The membrane filter shall be applied to the adhesive side of the tape
using tweezers.
f. The tape shall be uniformly adhered to the membrane filter surface and
shall be free of voids, bubbles or un-adhered areas.
NOTE The tape can be smoothed on the membrane
filter as per 5.1.1.4a.3.
g. The remainder of the tape shall be removed from the surface using a
constant speed of less than 1 cm/s.
h. Excess tape not attached to the membrane filter shall be removed using
scissors or a scalpel.
i. The membrane filter/tape assembly shall be placed into the tape-lift
sample holder and the sample holder lid closed.
j. The tape-lift sample holder shall be labelled with the time and date the
tape-lift was performed, the operator performing the test, and a unique
reference for the tape-lift test.
k. The area of the space craft system where the tape has been applied shall
be inspected for any damage, remaining particulate or molecular
contamination.
l. Any damage, particulate or molecular contamination shall be
documented in the Contamination Monitoring Report specified in Annex
C.
m. Where remaining particulate contamination has been observed, the tape-
lift test shall be repeated.
n. The tape-lift sample shall be analysed by the microscope counting
method as specified in 5.3.
5.1.2 Direct deposition on silicon wafers
5.1.2.1 Introduction
This clause describes the deposition on silicon wafers method to be used for the
sampling of surfaces with the purpose of determining particulate
contamination levels, and defining the particle size distribution. In this case, the
surface particulate is analysed directly without any transfer method, i.e. the
particles collected on the silicon wafer are directly analysed using an optical
microscope.
The method can also be applied to other non-diffusing surfaces, e.g. glass,
polished aluminium.
5.1.2.2 General requirements
a. Any silicon wafer witness preparation to be used for determining
particulate contamination levels using the deposition on silicon wafers
method shall be performed in a cleanliness controlled area.
b. Any counting to be used for determining particulate contamination levels
using the deposition on silicon wafers method shall be performed in a
cleanliness controlled area.
c. The location and orientation of the silicon wafers shall be representative
of the items for which this monitoring method applies.
5.1.2.3 Apparatus
a. The following apparatus shall be used to perform a deposition on silicon
wafers method:
1. A silicon wafer
NOTE Typically 2 inches diameter silicon wafers are
used.
2. Non-shedding and lint-free gloves
3. Tweezers
4. A container for the exposure and transport of the silicon wafer to
the measurement facility.
b. The container shall be devoid of particulate contamination that can
influence the assessment of the silicon wafer sample.
c. The container shall be sealable to prevent external contamination from
reaching the internal parts of the container.
d. The container shall provide the capability to keep in a fixed position the
silicon wafer.
e. The container, when lying horizontal, shall keep the surface of the silicon
wafer horizontal.
f. The container shall ensure the capability to maintain the silicon wafer
horizontal during the particulate counting, without any need to remove
the silicon wafer from the container.
5.1.2.4 Preparation of silicon wafers witnesses
a. The preparation of the silicon wafers’ witnesses shall be performed as
follows:
1. Using gloves and tweezers take one new or just cleaned silicon
wafer.
2. Visually inspect the silicon wafer surface and edge conditions.
(a) In case of edge damages, the silicon wafer is rejected.
(b) In case of particulate or non-particulate matter, or a
combination of both, visible on the surface, the silicon wafer
is re-clean.
3. Place silicon wafer in the container.
4. Perform a background measurement with the microscope counting
method (see 5.3).
5. Close the container.
5.1.2.5 Transportation of silicon wafers witnesses
a. The silicon wafer witness shall always be transported in its container and
in a horizontal position, the sampling surface facing upwards.
NOTE Since transportation is relocating particles,
measurement equipment is preferably located
close to measurement sites.
5.1.2.6 Exposure of silicon wafer witnesses
a. Handling of the witnesses shall be limited to the operations needed for its
preparation, transportation to the measurement site and exposure.
b. Any additional handling and transportation shall be documented in the
Contamination Monitoring Report specified in Annex C.
c. Once exposed in one mode or position, the witness shall never be re-used
before assessment of the contamination and cleaning.
d. An exposed witness should not be moved from its measurement position.
e. Any move of the exposed witness shall be documented in the
Contamination Monitoring Report specified in Annex C.
f. The container shall only be opened in situ.
NOTE It is important that the person performing the
witness deployment wears cleanroom garments
as required for the room.
g. Any witness handling, deployment and measurement, shall be
performed wearing non-shedding and lint-free gloves.
h. After exposure, the container shall be closed in-situ.
5.1.2.7 Analysis of silicon wafer witnesses
a. The silicon wafer witness shall be analysed with the microscope counting
method as specified in see 5.3.
5.1.3 Rinsing (direct or indirect)
5.1.3.1 Introduction
This section describes the method for determining particle contamination levels
from a liquid rinse that has been used to remove particles from the surface to be
assessed.
5.1.3.2 General requirements
a. Any counting for determining particle contamination levels from a liquid
rinse, shall be performed in a cleanliness controlled area.
b. The rinsing or immersion liquid shall be compatible with the material of
the surface to be sampled, the specified application and the membrane
filter used in the subsequent analysis.
c. The rinsing or immersion liquid shall be the most effective, or a
combination of the most effective, in removing contaminants.
NOTE 1 Typically, the rinsing or immersion liquid is the
agent used for the last cleaning, if applicable.
NOTE 2 When performed together with NVR analysis,
the selection of the rinsing or immersion fluid is
usually driven by the required NVR extraction
effectiveness.
d. De-ionized water, IPA, MEK, acetone, ethanol and the fluids listed in ISO
14952-3 paragraph 4.4.2 should be used as rinsing or immersion liquids.
e. The area of the rinsed surface shall be measured.
f. When the measurement is not practicable, the best estimate shall be
provided.
g. The minimum rinsed area shall be large enough to allow the verification
of required cleanliness levels.
h. If only the internal surface of a component is sampled, cross
contamination of particles from the external surface shall be avoided.
i. For small items that can be transported to the measurement area, the
items should be transported in a clean antistatic bag, avoiding friction or
movement that can generate particles.
j. Items that have a geometry for which simple rinsing is not demonstrated
effective for particle removal shall be placed in a pre-cleaned ultrasonic
bath with the solvent for at least 15 minutes and then rinsed with the
solvent.
NOTE This can be applied for example to the threaded
holes (that are often drilled and tapped) used
for the screw attachment of fittings to parts and
structures; such recesses are important sources
of particle contamination that is difficult to
detect.
k. When the ultrasonic method is used to transfer particulate to the
sampling liquid, it shall be verified that ultrasonics are compatible with
items and surfaces prior to sampling.
NOTE For example, ECSS-Q-ST-70-08 precludes the
use of ultrasonics to PCBs populated with
components.
l. When ultrasonics is not feasible, an equivalent method agreed with the
customer shall be used.
m. For vertical surfaces that are fixed to a structure larger than the surface
under measurement, or are otherwise unable to be removed to the
measurement area, the whole surface should be rinsed with the solvent
using a clean syringe, in situ, and the fluid collected in a previously
cleaned container.
5.1.3.3 Method for the sampling of external surfaces on
small items
5.1.3.3.1 Introduction
The present clause 5.1.3.3 describes the method to be used for the sampling of
external surfaces on small items by liquid immersion and rinsing. This
procedure does not apply to items that have only inner surfaces of interest (e.g.
pipes or enclosed recesses). This method does not apply to large surfaces and
large items that are not able to be immersed in an ultrasonic bath, either due to
size or non-compatibility with ultrasonics. In this method, the particles from the
surface to be analysed are transferred to the liquid medium and subsequently
analysed using the microscope counting method described in 5.3.
5.1.3.3.2 Apparatus
a. The apparatus shall be as specified in 5.2.1, with the following additional
items:
1. Previously cleaned metal or glass container,
2. Ultrasonic bath,
3. Clean syringe for applying solvent to the surface for rinsing.
5.1.3.3.3 Sampling procedure
a. Test fluid shall be added to completely immerse the test item in the
previously cleaned container.
b. Sampling shall be performed as follows:
1. Immerse the component in the container and apply ultrasonic
vibration for 5 minutes.
2. Using the syringe, rinse the component with the test fluid from the
solvent dispenser and add the rinsing to the immersion fluid.
3. Rinse the inner surfaces of the transportation bag directly into the
reservoir.
4. Record the total volume of test fluid used.
5. Analyse the fluid in accordance with 5.2.1.
5.1.3.4 Method for the sampling of external surfaces on
large items
5.1.3.4.1 Introduction
The present clause 5.1.3.4 describes the method of assessing particulate
contamination on large surfaces that cannot be analysed by the method
described in 5.1.3.3.
5.1.3.4.2 Apparatus
a. The apparatus shall be as specified in 5.1.2.3, with the following
additional items:
1. Previously cleaned metal or glass container,
2. Clean syringe for applying solvent to the surface for rinsing.
5.1.3.4.3 Sampling procedure
a. The sampling procedure shall be as follows:
1. Using the syringe, rinse the surface to be analysed with solvent
over a pre-determined area, and collect the solvent in a clean
container.
2. Inspect the area for any remaining particles.
3. Continue to apply solvent rinses to the surface until the surface is
visibly clean.
4. Record the total volume of solvent used.
5. Analyse the fluid in accordance with 5.2.1.
5.1.3.5 Method for the measurement of internal surfaces
5.1.3.5.1 Introduction
The method described in this clause is applicable to components that have
internal surfaces from which fluid can be applied and extracted.
5.1.3.5.2 Apparatus
a. The apparatus shall be as specified in 5.1.2.3, with the following
additional items:
1. Clean container with lid to collect the solvent after rinsing,
2. Petri dish.
5.1.3.5.3 Sampling procedure
a. The sampling procedure shall be as follows:
1. Remove caps or plugs, or both, from the field holder and place
them in a covered, pre-cleaned Petri dish;
2. Fill the component with the pre-filtered test solvent;
3. Reinstall the caps/plugs and vibrate the component;
4. Vibrate the component;
5. Extract the test fluid and analyze it in accordance with clause 5.2.1.
5.2 Volume sampling
5.2.1 Particles sampling from filtered liquid
samples
5.2.1.1 Introduction
This clause describes a procedure for sampling, sizing and counting of
particulate contamination in a liquid sample using a microscope. A known
quantity of liquid sample is filtered through a membrane filter under vacuum.
The particles trapped on the filter surface are sized and counted by microscopic
analysis (see 5.3).
5.2.1.2 General requirements
a. Any counting for the purpose of particle measurements from filtered
liquid samples shall be performed in a cleanliness controlled area.
b. The liquid sample for particle measurements from filtered liquid samples
shall be selected on the basis of its compatibility with the membrane
filter.
5.2.1.3 Apparatus
a. The following apparatus shall be used to perform particulate
contamination measurements from a liquid sample:
1. A membrane filter which provides contrast with the particulate
contaminants being analyzed
2. Sintered glass membrane filter holder
3. Buchner filter flask (1 litre capacity)
4. Vacuum source (vacuum pump or Venturi)
5. Fluid dispenser
6. Ultrapure water or solvent
7. Clean syringe
8. Petri dishes with covers
9. Forceps
5.2.1.4 Method
5.2.1.4.1 Initial preparation of glassware
a. All of the glassware should be ultrasonically cleaned before the
measurement by washing in hot water with a detergent.
b. The glassware shall then be rinsed with filtered de-ionised water and
filtered IPA and dried.
c. All cleaned equipments shall be stored in a clean area with openings
covered with a non-shedding and lint-free cover.
5.2.1.4.2 Background test
a. A background test shall be performed prior to the sample measurement
by the following method:
1. Set up the apparatus as shown in Figure 5-1.
2. Apply vacuum to the apparatus by attaching the vacuum feed to
the vacuum attachment on the Buchner flask.
3. Using a clean syringe, introduce 200 ml of membrane filtered
ultrapure water or the solvent used within the solvent reservoir,
taking care to rinse the complete inner surface of the solvent
reservoir.
4. After filtration, apply vacuum for few minutes in order to dry the
membrane filter.
5. Using forceps, immediately place the filter in a clean Petri dish and
place the cover on the Petri dish.
6. Mark the Petri dish with the sample reference.
7. Perform a microscopic particle count as described in clause 5.3.
8. Record the background count.
5.2.1.4.3 Sample test
a. The sample test shall be performed by the method described below:
1. Set up the apparatus as shown in Figure 5-1.
2. Apply vacuum to the apparatus.
3. Fill the solvent reservoir with the fluid to be analyzed.
4. After filtration, apply vacuum for few minutes in order to dry the
membrane disk.
5. Using forceps, immediately place the filter in a clean Petri dish and
place the cover on the Petri dish.
6. Mark the Petri dish with the sample reference.
7. Place the sample on the microscope sample stage and perform a
microscopic particle count as described in clause 5.3.
8. Record the sample count.
Eluent
Graded seal
Membrane
filter
vacuum
Buchner flask
Figure 5-1: Schematic for vacuum filtering apparatus
5.2.2 Particles sampling from filtered gas samples
5.2.2.1 Introduction
This clause describes a procedure for sampling, sizing and counting of
particulate contamination in a gas sample using a microscope. The particulate
contamination is separated from the gas sample by passing the gas through a
membrane filter, to allow a particle contamination count. This procedure is also
applicable to the cleanliness verification of flow-through fluid systems
assembled with cleaned components, in order to verify the cleanliness after the
assembly.
5.2.2.2 General requirements
a. Any counting of particulate contamination in a gas sample shall be
performed in a cleanliness controlled area.
b. The gas shall be chemically compatible with the membrane filter.
c. The gas pressure shall not damage the membrane filter.
5.2.2.3 Apparatus
a. The following apparatus shall be used to perform particulate
contamination measurements from a gas sample.
1. Membrane filter
2. Filter ho
...