ASTM F24-20
(Test Method)Standard Test Method for Measuring and Counting Particulate Contamination on Surfaces
Standard Test Method for Measuring and Counting Particulate Contamination on Surfaces
ABSTRACT
This test method establishes the standard procedures for measuring and quantizing the size distribution of particulate contamination either on, or washed from, the surface of small electron-device components. The apparatuses and reagents required for this test are also enumerated herein. The number of required test specimens is governed by the dimensions of the component or surface being analyzed. Results shall be interpreted as particles per component or particles per square centimetre of component surface.
SCOPE
1.1 This test method covers the size distribution analysis of particulate contamination, 5 μm or greater in size, either on, or washed from, the surface of small electron-device components. A maximum variation of two to one (±33 % of the average of two runs) should be expected for replicate counts on the same sample.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F24 − 20
Standard Test Method for
Measuring and Counting Particulate Contamination on
1
Surfaces
ThisstandardisissuedunderthefixeddesignationF24;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.1.4 planar surface, n—asurfacethatdoesnotmoveoutof
the depth of field of the microscope when the area to be
1.1 This test method covers the size distribution analysis of
observed is traversed under the highest magnification to be
particulate contamination, 5µm or greater in size, either on, or
used.
washedfrom,thesurfaceofsmallelectron-devicecomponents.
Amaximum variation of two to one (633% of the average of
3. Summary of Method
two runs) should be expected for replicate counts on the same
3.1 This test method comprises two procedures for prepar-
sample.
ing specimens for microscopical analysis: one for adhered
1.2 Units—The values stated in SI units are to be regarded
particles on planar surfaces and the second for particulate
asstandard.Nootherunitsofmeasurementareincludedinthis
contamination removed from irregular surfaces.
standard.
3.2 A single optical analysis procedure is presented for
1.3 This standard does not purport to address all of the
particle enumeration in stated size ranges.
safety concerns, if any, associated with its use. It is the
3.3 For planar surfaces, the component is mounted on a
responsibility of the user of this standard to establish appro-
suitableflatsupportandmountedonthemicroscopestage.For
priate safety, health, and environmental practices and deter-
irregularsurfacecomponents,thecontaminationisremovedby
mine the applicability of regulatory limitations prior to use.
subjectingthecomponenttoanultrasoniccavitationfieldwhile
1.4 This international standard was developed in accor-
immersed in water containing a detergent.
dance with internationally recognized principles on standard-
3.4 The contamination is subsequently transferred to a
ization established in the Decision on Principles for the
membrane filter disk by filtration and then examined micro-
Development of International Standards, Guides and Recom-
scopically.
mendations issued by the World Trade Organization Technical
3.5 Microscopical analysis of the contaminant is conducted
Barriers to Trade (TBT) Committee.
at two magnifications using a gating measurement technique
with oblique incident lighting.
2. Terminology
3.6 Particles are counted in three size ranges: >100µm, 25
2.1 Definitions:
to 100µm, 5 to 25µm, and fibers.
2.1.1 fiber, n—a particle longer than 100µm and with a
3.7 For low-contamination levels on irregularly shaped
length to width ratio of greater than 10:1.
components, a procedure for running a blank is described.
2.1.2 particulate contaminant, n—a discrete quantity of
3.8 The method requires strict adherence to the procedures
matter that is either foreign to the surface on which it rests or
for cleaning apparatus.
may be washed from the surface on which it rests by the
ultrasonic energy procedure herein described.
4. Apparatus
2.1.3 particle size, n—the maximum dimension of the par-
4.1 Microscope, with mechanical stage, approximately 45
ticle.
and100×.For100×magnification,therecommendedobjective
is 10 to 12× (but a minimum of 6×) with a numerical aperture
of 0.15 minimum. The optimum equipment is a binocular
1
This test method is under the jurisdiction of ASTM Committee E21 on Space
microscope with a micrometer stage. A stereomicroscope
Simulation andApplications of SpaceTechnology and is the direct responsibility of
should not be used in this procedure.
Subcommittee E21.05 on Contamination.
Current edition approved April 1, 2020. Published April 2020. Originally
4.2 Ocular Micrometer.
approved in 1962. Last previous edition approved in 2015 as F24–09(2015). DOI:
10.1520/F0024-20. 4.3 Stage Micrometer, having 0.1 to 0.01mm calibration.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
F24−20
4.4 Light Source—An external incandescent high-intensity, 7.2.2 After washing, rinse the equipment with membrane-
6-V, 5-A source with transformer. filtered water and membrane-filtered isopropyl alcohol and
drain dry.
4.5 Microscope Slides—Glass slides 50 by 75 mm.
7.2.3 For use at low-contamination levels, check the clean-
4.6 Plastic Film—Wash with membrane-filtered isopropyl
ness of the equipment by conducting successive blank analy-
alcohol.
ses.
4.7 Solven
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F24 − 09 (Reapproved 2015) F24 − 20
Standard Test Method for
Measuring and Counting Particulate Contamination on
1
Surfaces
This standard is issued under the fixed designation F24; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the size distribution analysis of particulate contamination, 5 μm 5 μm or greater in size, either on,
or washed from, the surface of small electron-device components. A maximum variation of two to one (633 % of the average of
two runs) should be expected for replicate counts on the same sample.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Terminology
2.1 Definitions:
2.1.1 fiber, n—a particle longer than 100 μm and with a length to width ratio of greater than 10:1.
2.1.2 particulate contaminant—contaminant, n—a discrete quantity of matter that is either foreign to the surface on which it
rests or may be washed from the surface on which it rests by the ultrasonic energy procedure herein described.
2.1.3 particle size—size, n—the maximum dimension of the particle.
2.1.3 fiber—a particle longer than 100 μm and with a length to width ratio of greater than 10:1.
2.1.4 planar surface—surface, n—a surface that does not move out of the depth of field of the microscope when the area to be
observed is traversed under the highest magnification to be used.
3. Summary of Method
3.1 This test method comprises two procedures for preparing specimens for microscopical analysis: one for adhered particles
on planar surfaces and the second for particulate contamination removed from irregular surfaces.
3.2 A single optical analysis procedure is presented for particle enumeration in stated size ranges.
3.3 For planar surfaces, the component is mounted on a suitable flat support and mounted on the microscope stage. For irregular
surface components, the contamination is removed by subjecting the component to an ultrasonic cavitation field while immersed
in water containing a detergent.
3.4 The contamination is subsequently transferred to a membrane filter disk by filtration and then examined microscopically.
3.5 Microscopical analysis of the contaminant is conducted at two magnifications using a gating measurement technique with
oblique incident lighting.
3.6 Particles are counted in three size ranges: >100 μm, >100 μm, 25 to 100 μm, 100 μm, 5 to 25 μm, 25 μm, and fibers.
3.7 For low-contamination levels on irregularly shaped components, a procedure for running a blank is described.
1
This test method is under the jurisdiction of ASTM Committee E21 on Space Simulation and Applications of Space Technology and is the direct responsibility of
Subcommittee E21.05 on Contamination.
Current edition approved Oct. 1, 2015April 1, 2020. Published November 2015April 2020. Originally approved in 1962. Last previous edition approved in 20092015 as
F24 – 09.F24 – 09(2015). DOI: 10.1520/F0024-09R15.10.1520/F0024-20.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
F24 − 20
3.8 The method requires strict adherence to the procedures for cleaning apparatus.
4. Apparatus
4.1 Microscope, with mechanical stage, approximately 45 and 100×. For 100× magnification, the recommended objective is 10
to 12× (but a minimum of 6×) with a numerical aperture of 0.15 minimum. The optimum equipment is a binocular microscope
with a micrometer stage. A stereomicroscope should not be used in this procedure.
2
4.2 Ocular Micrometer,Micrometer. B & L 31–16–10.
4.3 Stage Micrometer, B & L 31–16–99,h
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