ASTM F24-04

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Designation:F24–04
Standard Test Method for
Measuring and Counting Particulate Contamination on
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Surfaces
ThisstandardisissuedunderthefixeddesignationF 24;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.5 Microscopical analysis of the contaminant is conducted
at two magnifications using a gating measurement technique
1.1 This test method covers the size distribution analysis of
with oblique incident lighting.
particulate contamination, 5 µm or greater in size, either on, or
3.6 Particles are counted in three size ranges: >100 µm, 25
washedfrom,thesurfaceofsmallelectron-devicecomponents.
to 100 µm, 5 to 25 µm, and fibers.
Amaximum variation of two to one (633 % of the average of
3.7 For low-contamination levels on irregularly shaped
two runs) should be expected for replicate counts on the same
components, a procedure for running a blank is described.
sample.
3.8 The method requires strict adherence to the procedures
2. Terminology
for cleaning apparatus.
2.1 Definitions:
4. Apparatus
2.1.1 particulate contaminant—adiscretequantityofmatter
4.1 Microscope, with mechanical stage, approximately 45
that is either foreign to the surface on which it rests or may be
and 1003. For 1003 magnification, the recommended objec-
washed from the surface on which it rests by the ultrasonic
tive is 10 to 123 (but a minimum of 63) with a numerical
energy procedure herein described.
aperture of 0.15 minimum. The optimum equipment is a
2.1.2 particle size—themaximumdimensionoftheparticle.
binocular microscope with a micrometer stage.Astereomicro-
2.1.3 fiber—a particle longer than 100 µm and with a length
scope should not be used in this procedure.
to width ratio of greater than 10:1.
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4.2 Ocular Micrometer,B&L 31–16–10.
2.1.4 planar surface—a surface that does not move out of
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4.3 Stage Micrometer, B & L 31–16–99, having 0.1- to
the depth of field of the microscope when the area to be
0.01-mm calibration.
observed is traversed under the highest magnification to be
4.4 Light Source—An external incandescent high-intensity,
used.
6-V, 5-A source with transformer.
3. Summary of Method
4.5 Microscope Slides—Glass slides 50 by 75 mm.
4.6 Plastic Film—Wash with membrane-filtered isopropyl
3.1 This test method comprises two procedures for prepar-
alcohol.
ing specimens for microscopical analysis: one for adhered
4.7 Solvent Filtering Dispenser.
particles on planar surfaces and the second for particulate
4.8 Membrane Filter Holder, having 47-mm diameter and
contamination removed from irregular surfaces.
heat-resistant glass base.
3.2 A single optical analysis procedure is presented for
4.9 Filter Flask,1L.
particle enumeration in stated size ranges.
4.10 Membrane Filters, having 47-mm diameter, 0.45-µm
3.3 For planar surfaces, the component is mounted on a
pore size, black, grid marked.
suitable flat support and mounted on the microscope stage. For
irregularsurfacecomponents,thecontaminationisremovedby
subjectingthecomponenttoanultrasoniccavitationfieldwhile
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immersed in water containing a detergent. The sole source of supply of the ocular micrometer,B&L 31–16–10, known
to the committee at this time is Bausch & Lomb, One Bausch & Lomb Place,
3.4 The contamination is subsequently transferred to a
Rochester,NY14604–2701.Ifyouareawareofalternativesuppliers,pleaseprovide
membrane filter disk by filtration and then examined micro-
this information to ASTM International Headquarters. Your comments will receive
scopically. 2
careful consideration at a meeting of the responsible technical committee, which
you may attend.
3
The sole source of supply of the stage micrometer,B&L31–16–99, known to
the committee at this time is Bausch & Lomb, One Bausch & Lomb Place,
1
This test method is under the jurisdiction of ASTM Committee E21 on Space Rochester,NY14604–2701.Ifyouareawareofalternativesuppliers,pleaseprovide
Simulation andApplications of Space Technology and is the direct responsibility of this information to ASTM International Headquarters. Your comments will receive
3
Subcommittee E21.05 on Contamination. careful consideration at a meeting of the responsible technical committee, which
Current edition approved Sept. 1, 2004. Published September 2004. Originally you may attend.
approved in 1962. Last previous edition approved in 2000 as F 24 – 00.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F24–04
4.11 Vacuum Source—Pump or aspirator (tap recom- 7.2.8 Preclean a 0.45-µm black grid filter, 47 mm in
mended). diameter,b
...