SEM monitor workstation

Spectel announces the availability of the SEM Monitor, a diagnostic tool known as “Sharpness Analysis,” integrated into a turnkey workstation to meet the semiconductor industry`s need for analysis of production metrology scanning electron microscopes (SEMs). The tool`s analysis capability was developed for use as an on-line instrument diagnostic and for tool-matching in a production environment. It provides a quantitative framework based on fourier transform feedback for monitoring SEM resolution, astigmatism and image quality over time and for comparing it to other instruments. Information from the software analysis can then be used to adjust the SEM for optimum performance. In addition to the SEM Monitor software, image processing software and Spectel`s Metrologia electron beam and optical simulation software and characterization capabilities have been incorporated into the workstation.

Spectel Research, Mountain View, CA

(415) 254-0532

ISO/DIS 14644-1 now available

Mount Prospect, IL

The Institute of Environmental Sciences, Secretariat for ISO/TC 209 has announced the availability of ISO/DIS 14644-1, Cleanrooms and associated controlled environments — Part 1: Classification of airborne particulates. The document is the first Draft International Standard (DIS) produced by ISO Technical Committee 209, Cleanrooms and Associated Controlled Environments. Descriptors of this DIS include cleanrooms, air pollution, particulate air pollutant, and classification. This first ISO cleanroom standard is one of about 12 documents that will make up the new family of global cleanroom standards (See “ISO enters last lap in formalizing new cleanroom classification,” CleanRooms, February 1997, p. 1). Other documents will follow until the full family is complete, which may be as early as the end of 1999. The other documents will cover subjects such as cleanroom testing for compliance, biocontamination, metrology and test methods, cleanroom design and construction, cleanroom operations, minienvironments and isolators, and terms, definitions and units. The Institute says there are still opportunities to participate in the activities of ISO/TC 209. For more information, contact the IES at (847) 255-1561. – SES

Training video

A new videocassette from Texwipe demonstrates the proper use of cleanroom wipers in the semiconductor, disk drive, pharmaceutical and medical device manufacturing industries. “The Systematic Approach to Cleaning” is a 12-minute instructional video, written and produced by Texwipe. This video is an employee training tool for those who work in cleanrooms. Viewers are alerted to the high-cost of contamination in the various industries and how minute amounts of contamination such as fibers, particles, molecules or viable “bioburden” can greatly affect product yields and quality. Video highlights include: common wiping mistakes; dry wiping vs. wet wiping with cleaning solutions; safety concerns in hazardous spill removal and the proper disposal of hazardous solutions. In addition, the video offers advice on choosing the correct cleanroom wiper based on performance characteristics (absorption, wiper strength, particle shedding potential, ESD risk and non-volatile residue) as determined by the latest metrology techniques.

The Texwipe Company

Upper Saddle River, NJ

(800) TEXWIPE, Ext. 292

ISO Enters Last Lap in Formalizing New Cleanroom Classifications

BY Susan English

Geneva, Switzerland — Headquarters for the International Organization for Standardization (ISO) has just released its new Draft International Standard (DIS) for cleanrooms and associated controlled environments. ISO/DIS 14644-1, “Cleanrooms and associated controlled environments, Part 1: Classification of airborne particulate cleanliness for cleanrooms and clean zones” establishes three new classes of cleanliness. It also prescribes the standard method of testing, and includes a procedure for determining the concentration of airborne particles by mathematical formulas. Both industry and regulatory interests provided the impetus for DIS, and its creation was marked by a spirit of global cooperation. It incorporates many of the “Recommended Practices” of the Institute of Environmental Sciences and much of Federal Standard 209E, while assigning new ISO classification levels of air cleanliness in cleanrooms and associated controlled environments. This “keystone” document is the first of 10 to be produced by ISO`s Working Group 209 (ISO/TC209) (See “ISO/TC209 Sets Global Cleanroom Standards” CleanRooms, Aug. 1996, p. 27).

Other documents will cover subjects such as cleanrom testing for compliance, biocontamination, metrology and test methods, cleanroom design and construction, cleanroom operations, minienvironments and isolators and terms, definitions and units. DIS 14644-1 is available for sale from the Institute of Environmental Sciences. It is presently out for review by all ISO member nations, and the deadline for receiving all comments is May. After a two-month period for incorporating those comments, it will be republished as a formal ISO Standard, which is expected to be this August.

Although non-mandatory, the ISO standard is significant in that it sets a universal standard for classifying cleanrooms, says TC209 committee chairman Dick Matthews.

The standard adds three new classes: ISO-1 (10 particles/m3 at 0.1&#181m), ISO-2 (100 particles/m3 at 0.1&#181m) to accommodate the trend toward more jam-packed chips and smaller wafer geometries; and ISO-9 (35,200,000 particles/m3 at 0.5 &#181m, which is intended to provide a guideline for the pharmaceutical industry in monitoring more gross particles, where the criteria is not as strict. ISO-1 and -2 would be comparable to a Federal Standard 209E Class 0.1 and a Class .01– if such classifications existed — says Matthews, while ISO-9 would be similar to a hypothetical Class 1,000,000.

ISO-1 and -2 sprang from the necessity of broadening the categories to accommodate changing technologies on the one hand and real world applications on the other. In the microelectronics industry, smaller and smaller line widths will mean monitoring for ultrafine particles in the nanometer range. ISO Class 9 is designed to facilitate better particle monitoring with powders and filling operations in the pharmaceutical industry. In addition, the standard offers something that does not exist in many other standards, and only to some extent in Federal Standard 209E: a procedure for calculating alternative levels of air cleanliness for particle populations not within the classification size range. Says Matthews: “Let`s say you have to control a 0.15 micron particle to so many units: the formula takes the particle size, the class you`re trying to get, and tells you how many particles you can have at that size in order to be at, say, ISO Class 3.” n

Texwipe offers training video on how to clean the cleanroom

Upper Saddle River, NJ–The Texwipe Company announced the availability fo a videocassette, “A Systematic Approach to Cleaning,” which demonstrates the proper use of cleanroom wipers in the semiconductor, disk drive, pharmaceutical and medical device manufacturing industries. The 12-minute instructional video is designed to be used as an employee training tool for thsoe who work in cleanrooms and their managers. Viewers are alerted to the high cost of contamination in the various industries and how minute amounts of contamination such as fibers, particles, molecules or viable bioburden can greatly affect product yields and quality. SEM photos provide vivid illustrations.

Video highlights include: common wiping mistakes; dry wiping vs. wet wiping with cleaning solutions; safety concerns in hazardous spill removal and the proper disposal of hazardous solutions; choosing the correct cleanroom wiper, based on performance characteristics (absorption, wiper strength, particle shedding potential, ESD risk and non-volatile residue) as determined using the latest metrology techniques. n

IES Progresses on ISO Cleanroom Standards

By John Haystead

Anaheim, CA–Three of seven ISO Technical Committee Working Groups met in Anaheim, CA last month during the IES`s annual technical meeting and exhibition to continue work on a package of international standards for “Cleanrooms and Associated Controlled Environments” (ISO/TC209). The IES was appointed in 1993 as the ISO Secretariat organization responsible for this activity by the American National Standards Institute (ANSI). According to Richard Matthews of Filtration Technology, Inc. and Chairman of ISO Technical Committee 209, when completed, “the standards will basically encompass the `how-to`s` of designing, building and living in a cleanroom environment.”

At one of the three meetings, Working Group One (WG01) reviewed a working-draft document on “Classifications of Air Cleanliness.” The group had previously circulated this document to industry for comments, and their feedback is now being incorporated into a revised version. Plans call for the modified document to be presented at the next ISO/TC209 technical committee meeting being held this month in London, England. If accepted by the committee, the draft standard will be circulated to all of the participating nations for comment and then for a final acceptance vote. The full process could be completed by early 1996.

Working Group 3 (WG03) on “Metrology and Test Methods” also met to review a list of the various tests and test methods for maintaining the integrity of a clean environment, such as how to test a HEPA filter, measure air flow, etc. Ultimately, the group will compile their lists into a standard set of tests and procedures. The WG03 group will meet next at the ISO/TC209 meeting in Milan, Italy in March of `96.

Meeting formally for the first time, the Working Group on “Cleanroom Operations” standards (WG05) established preliminary parameters and agenda items for their group`s area. WG05 will also have their next meeting in Milan.

The Standing Committee of the International Confederation of Contamination Control Societies (ICCCS) also convened a meeting in Anaheim. Ac-

cording to Matthews, most of these discussions were also centered around the efforts of the ISO body. “The committee attempted to use the ICCCS group as a preliminary international sounding board to informally and non-politically hash out and identify some of the technical issues on the table.” In fact, many of the ICCCS standing committee members are also delegates to various ISO working groups.

There are two levels of participation defined for the ISO standard development process. Sixteen “participating,” or P-Nations, have actual voting authority on the standards, but another group, or “observer” nations, can provide comments on the documents. At the working group level, each P-Nation is entitled to send two delegates to each panel, but in reality, only 8 to 12 are usually represented on any one group. There is, however, a minimum requirement for at least five nations to be represented.

The other four TC209 working groups are: WG02 dealing with Biocontamination standards and scheduled to meet in Washington, D.C. in September; WG04 on Cleanroom Design and Construction which met in Berlin, Germany in February and will meet again in London in July; WG06 on Terms, Definitions and Units, which will first meet formally next spring; and WG07 on Clean Air Devices which had its initial meeting in Geneva in early April and will also meet in Washington in September.

According to Matthews, there are no major roadblocks ahead for any of the standards processes, but there is one area of concern. This is the entire area of biocontamination and how this should be handled in light of its close scrutiny and monitoring by various government regulatory agencies. “When we get into these regulatory issues, things get more stringent, and go beyond the scope of TC209,” says Matthews. He points out that, whereas in many countries, the national standards organization is also a government agency, this is not the case in the United States.

Matthews is certain, however, that the standards put in place by the ISO/TC209 Committee will ultimately have a very definite economic impact on the cleanrooms industry as well as on the industries that rely on contamination control technology. “The standards are partially designed to reduce trade barriers and to create a level playing field. Anybody building a cleanroom anywhere in the world will be working from the same common denominator and the same set of parameters. This should open up the international market for users as well as suppliers, since products manufactured in ISO-approved facilities will be marketable anywhere in the world.”

ISO cleanroom standards will have a particularly strong and immediate impact in Europe. Through the mandated process set up by the 19 European Community participants in the Council of European Nations (CEN), each individual nation`s own standards must be replaced by a common European CEN standard. And, since as a result of the “Vienna agreement,” ISO standards can be adopted in place of CEN standards, a decision which has already been made in the case of cleanrooms standards (CEN TC243), ISO standards will therefore be mandatory for European nations.

Although ISO standards will in principle be voluntary in the United States, if a regulatory agency such as the FDA steps in, that could also change. The FDA is already intimately involved with U.S. Technical Support Activity Groups (TAGs) and has delegates on many IES working groups.

According to Matthews, the overall target of ISO/TC209 is to have at least portions of the standard published by October, 1996. The first meeting of IES TC209 was held in Chicago in September of 1993, and although the average ISO standard takes roughly 84 months to complete, the committee felt they could shorten this time considerably to 36 months because of the level of desire and incentive expressed by both the cleanroom user and supplier communities.n