1、INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY Contamination Control Division Reco ended Practice 016.2 IEST-RP-C016.2 The Rate of Deposition of Nonvolatile Residue in Cleanrooms INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY Arlington Place One 2340 S. Arlington Heights Road, Suite 10 Arlin
2、gton Heights, IL 6005-4516 Phone: (847) 981-010 Fax: (847) 981-4130 E-mail: iestiest.org Web: ww.iest.org 2 Copyrighted material IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY Copyrighted material 3 This Recomended
3、Practice is published by the INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY to advance contamination control and the technical and enginering sciences. Its use is entirely voluntary, and determination of its aplicability and suitability for any particular use is solely the responsibility of the
4、user. This Recomended Practice was prepared by and is under the jurisdiction of Working Group 016 of the IEST Con-tamination Control Division. Copyright 202 by the INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY First printing, November 202 ISBN 978-1-87862-87-8 PROPOSAL FOR IMPROVEMENT: The Work
5、ing Groups of the INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY are continualy working on improvements to their Recomended Practices and Reference Docu-ments. Sugestions from those who use these documents are welcome. If you have a sugestion regarding this document, please use the online Propos
6、al for Improvement form found on the IEST website at ww.iest.org/proposal/form.html. INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY Arlington Place One 2340 S. Arlington Heights Road, Suite 10 Arlington Heights, IL 6005-4516 Phone: (847) 981-010 Fax: (847) 981-4130 E-mail: iestiest.org Web: ww.i
7、est.org 4 Copyrighted material IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY Copyrighted material 5 The Rate of Deposition of Nonvolatile Residue in Cleanrooms IEST-RP-C016.2 CONTENTS SECTION 1 SCOPE AND LIMITATION
8、S.7 2 BACKGROUND AND PURPOSE.7 3 REFERENCES8 4 TERMS, DEFINITIONS, AND SYMBOLS8 5 RATE OF DEPOSITION OF NONVOLATILE RESIDUE.10 6 DEPOSITION RATE CALCULATIONS.10 7 NVR DEPOSITION RATE LEVEL CONVERSIONS12 8 PHYSICS OF NVR DEPOSITION12 9 TECHNIQUES FOR MEASURING THE DEPOSITION OF NVR13 10 REPORTING AND
9、 ANALYSIS OF RESULTS.19 1 BIBLIOGRAPHY19 TABLE 1 NVR RATE LEVELS.1 2 CONVERSION FACTORS (1).13 3. APROXIMATE SENSITIVITIES OF VARIOUS AT-CUT QUARTZ CRYSTALS.17 FIGURE 1 LOCATIONS FOR SAMPLING IN A CLEANROM OR CLEAN ZONE HAVING NONUNIDIRECTIONAL AIRFLOW AND HAVING AN AREA SMALER THAN 15 M2(150 FT2)18
10、 2 LOCATIONS FOR SAMPLING IN A CLEANROM OR CLEAN ZONE HAVING NONUNIDIRECTIONAL AIRFLOW AND HAVING AN AREA BETWEN 15 M2(150 FT2) AND 10 M2(100 FT2).18 3. EXAMPLE OF LOCATIONS FOR SAMPLING IN A CLEANROM OR CLEAN ZONE HAVING HORIZONTAL UNIDIRECTIONAL AIRFLOW18 4. EXAMPLE OF LOCATIONS FOR SAMPLING IN A
11、CLEANROM OR CLEAN ZONE HAVING VERTICAL UNIDIRECTIONAL AIRFLOW.18 6 Copyrighted material IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY Copyrighted material 7 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY Contam
12、ination Control Division Recomended Practice 016.2 The Rate of Deposition of Nonvolatile Residue in Cleanrooms IEST-RP-C016.2 1 SCOPE AND LIMITATIONS 1.1 Scope This Recomended Practice (RP) provides a uniform method and basis for defining the rates of deposition of nonvolatile residue (NVR) and othe
13、r forms of mo-lecular contamination on surfaces in cleanroms. 1.2 Limitations This RP may be aplied to the certification of clean-roms or for monitoring cleanroms to the extent agred upon by the parties involved. In contractual agrements, the customer selects the specific meas-urements apropriate to
14、 the cleanrom under consid-eration. Specific aceptance limits are also defined in contractual agrements. The requirements for the maximum rate of deposition of NVR should be specified by the user. The speci-fied requirements can afect the design of the heating, ventilating, and air conditioning (HVA
15、C) system; the selection of suitable filters, and the selection of mate-rials users in the construction of the cleanrom. De-signers, builders, and users of cleanroms should consider specifying the maximum deposition rates as sugested by this RP if the deposition of NVR can afect the performance of p
16、roducts. The techniques for measuring NVR described in this document are not the only methods that can be used, but they should be considered because of their gen-eral use. The requirements for specific products and proceses should be considered in the selection of measurement methods. Products and
17、procedures contained in this RP may involve hazardous materials, operations, and equip-ment. This RP does not purport to adres al of the safety problems asociated with its use. It is the re-sponsibility of the user to establish apropriate safety and health practices and determine the aplicability of
18、 regulatory limitations prior to use of this RP. 2 BACKGROUND AND PURPOSE Cleanroms are designed to protect products from contaminants that afect the performance of those products. Molecular contaminants, introduced by the air that enters the cleanrom or by emisions from items within the cleanrom, a
19、re deposited onto surfaces in the form of thin films or droplets; these types of de-posits are caled NVR. The molecular contaminants are typicaly transported in the air as gases or as liq-uid aerosols. This type of contamination is frequently refered to as airborne molecular contamination or AMC. Th
20、is RP is for use in defining the cleanrom envi-ronment and may be used in a contract with the agrement of customer and suplier. In adition, this RP is intended to complement standards on alowable NVR and molecular contaminants on products, such as IEST-STD-C1246. 8 Copyrighted material IEST-RP-C016.
21、2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY 3 REFERENCES The most recent editions of the folowing documents are a part of this RP to the extent described herein. For dated references, subsequent amendments to, or revisions of, any of these publications do not aply. However, parties are enco
22、uraged to use the most re-cent editions of the documents indicated in Section 3.1. For undated references, the latest edition of the references aplies. 3.1 Aplicable documents ASTM E573: Standard Practices for Internal Reflec-tance Spectroscopy ASTM E1234: Standard Practice for Handling, Transportin
23、g, and Instaling Nonvolatile Residue (NVR) Sample Plates Used in Environmentaly Controled Areas for Spacecraft ASTM E1235: Standard Method for Gravimetric Determination of Nonvolatile Residue in Envi-ronmentaly Controled Areas for Spacecraft ASTM F1982: Standard Test Methods for Analyzing Organic Co
24、ntaminants on Silicon Wafer Sur-faces by Thermal Desorption Gas Chromatogra-phy IEST-RP-C07.1: Testing ULPA Filters IEST-STD-C1246: Product Cleanlines Levels and Contamination Control Program ISO 1464-1: Cleanroms and asociated controled environmentsPart 1: Clasification of air cleanlines 3.2 Source
25、s and addreses Referenced documents may be obtained from the folowing sources: ASTM International 10 Bar Harbor Drive West Conshohocken, PA 19428-2959 USA eb: ww.astm.org IEST Institute of Environmental Sciences and Technology 2340 S. Arlington Heights Road, Suite 10 Arlington Heights, IL 6005-4516
26、USA Web: ww.iest.org ISO 1464-1 Available from ember body in the country of the requester. USA: IEST 4 TERMS, DEFINITIONS, AND SYBOLS absorbance, A In spectrochemical analysis, the logarithm to the base 10 of the reciprocal of the transmitance. A = log (1/) Note: Also known as absorbancy or extincti
27、on. aerosol gaseous suspension of fine solid or liquid particles airborne molecular contamination, AMC contaminants in the form of gases, vapors, or liquid aerosols analyte sample being analyzed clean workstation clean-air device such as a bench or similar enclosure, characterized by having its own
28、suply of filtered air clean zone defined space in which the concentration of contami-nants is controled to within user-specified limits cleanlines level a) designation indicating the maximum amount of contamination alowed per unit of area or volume or on the defined surface of a component b) measure
29、d extent of contamination cleanrom enclosed area in which there is control over airborne particles, temperature, humidity, molecular species, presure, activities, and other environmental variables so aceptable products can be produced; HEPA or ULPA filters are required for the incoming air cleanrom
30、ocupancy states as-built pertaining to a clean area that is complete and ready for operation, with al services conected and functional, but without proces equipment or personel within the clean area at-rest pertaining to a clean area that is complete and has al proces equipment instaled and operat-i
31、ng, but without personel in the clean area operational pertaining to a clean area in normal operation, with al services functioning, and with al proc-es equipment and personel present and per-forming their normal work functions within the clean area IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES
32、 AND TECHNOLOGY Copyrighted material 9 condensation proces of converting a material in the gaseous phase to a liquid or solid state; an equilibrium proces that is favored one way or the other by a change in tem-perature, presure, or both contaminant unwanted material, substance, or form of energy wh
33、ose presence wil adversely afect the product or proces contaminant source rate rate at which a contaminant is generated evaporation proces by which a material is transformed from the liquid or solid state to the gaseous state Note: This is an equilibrium proces that is fa-vored in one direction or t
34、he other in re-sponse to a change in temperature or presure, or both. exposure time period during which a product or witnes surface is in direct contact with the environment in a cleanrom or clean zone far UV ultraviolet radiation with wavelengths les than ap-proximately 280 nm; also caled vacum UV
35、gravimetric analysis standard analytical technique aplied to the quantifi-cation of NVR: the contaminated surface is first rinsed with a clean solvent having a low NVR that has ben measured, a standard quantity of solvent is evaporated, and the mas of the substance remaining is determined; this resi
36、duethe NVR minus the NVR of the clean solventis expresed as mas per unit area of surface HEPA (high-eficiency particulate air) filter replaceable, extended-medium, dry-type filter in a rigid frame, having a minimum particle-colection eficiency of 9.97%that is, a maximum particle penetration of 0.03%
37、for 0.3-m particles of ther-maly-generated DOP (dioctylphthalate) or specified alternative aerosol interdigital transducer two interlocking, comb-shaped, metalic paterns aplied to a piezoelectric substrate such as quartz or lithium niobate, used for converting microwave volt-ages to surface acoustic
38、 waves or vice versa monitoring observations made by measurement in acordance with a defined method and plan to provide evidence of the performance of an instalation Note: This information may be used to detect trends in the operational state to provide proces suport and in the at-rest state to eval
39、uate facility performance. nonunidirectional airflow airflow that does not qualify as unidirectional be-cause it has a multiplicity of flow directions or multi-ple-pas circulation (edies), or both nonvolatile residue (NVR) mater that remains after the solvent containing such mater has ben filtered a
40、nd evaporated at a specified temperature NVR deposition rate deposition of NVR as a function of time; units are mas per unit area and time NVR deposition rate level NVR deposition rate level is the log10of the NVR deposition rate in pgm-2s-1. Note: Deposition rate levels are defined in Table 1. sorp
41、tion taking up of gas or liquid molecules by proceses that include absorption, adsorption, and chemisorption absorption taking up of gas or liquid molecules by a liquid or solid and distributed throughout the body of that liquid or solid adsorption proces in which molecules of gases or liquids are c
42、oncentrated on a surface by chemical or physical forces, or both chemisorption (chemical adsorption) binding of atoms or molecules to the surface of a solid by forces whose energy levels aproximate those of a chemical bond sublimation evaporation of a solid directly to the gaseous state without pasi
43、ng through the liquid state transmitance, ratio of the transmited radiant or luminous flux to the incident flux ULPA (ultra-low-penetration air) filter replaceable, extended-medium, dry-type filter in a rigid frame, having a minimum particle-colection eficiency of 9.99%that is, a maximum particle pe
44、netration of 0.01%for particles in the size range of 0.1 to 0.2 m when tested in acordance with the methods of IEST-RP-C07.1 10 Copyrighted material IEST-RP-C016.2 INSTITUTE OF ENVIRONMENTAL SCIENCES AND TECHNOLOGY unidirectional airflow air that flows in a single pas in a single direction through a
45、 cleanrom or clean zone with generaly paralel streamlines wavelength, distance in the direction of propagation of a periodic wave betwen two sucesive points at which the phase is the same at the same time wavenumber, number of waves per unit length in units cm-1 witnes surface surface used to colect
46、 contaminants during exposure and then removed and analyzed or measured after exposure 5 RATE OF DEPOSITION OF NONVOLATILE RESIDUE NVR deposition rate levels are defined in Table 1. The NVR deposition rate level is the log, base 10, of the deposition rate in pgm-2s-1. The equivalent depo-sition rate
47、 may be specified in other units that are consistent with the levels required and the proces being specified or measured. The number of significant figures used for the NVR deposition rate level and deposition rate should be consistent with the precision and acuracy of meas-urements and requirements
48、. The wide range of mas and time units in Table 1 reflects the ned to define NVR deposition rates for proceses and products that have large diferences in sensitivities to contamination. 6 DEPOSITION RATE CALCULATIONS 6.1 Rate of deposition of NVR using witnes surfaces mathematical expresion IEST-STD
49、-C1246 is frequently used to establish the maximum alowable level of NVR that a product can have when removed from a cleanrom. Since that maximum amount represents the sum of NVR that was on the product when the product was brought into the cleanrom plus the amount of NVR that was aded while the product was in the cleanrom, the maximum alowable average deposition rate within the cleanrom is determined by the folowing equa-tion: NVRdt=NVRf! NVRi( )t(1) where: NVRd= the NVR that has deposited on the product while in the clean-rom, in units such as
