Cleanroom

The cleanroom classification is illustrated in Table 2. By U.S. law, Federal Standard 209E can be superseded by new international standards.  The 209E standard will be phased out and replaced globally by ISO 14644.

ISO Class 8 (Fed Std. Class 100,000)

An ISO Class 8 cleanroom has no more than 3,520,000 particles per cubic meter equal to and larger than 0.5 microns.  For ISO Class 8, the Fed Std. 209E rating is Class 100,000.

In a Class 100,000 (ISO Class 8) cleanroom, amine-free antistatic and carbon products are extensively used.  Corrugated containers are seen in the facility, as well as garments and shoes with heel grounders.  A Class 100,000 cleanroom is not always a well-controlled environment.  Masks or gloves are not required.  Items shipped into an ISO Class 8 cleanroom do not require cleaning or bagging in advance.

ISO Class 7 (Fed Std. Class 10,000)

An ISO Class 7 cleanroom has no more than 352,000 particles per cubic meter equal to and larger than 0.5 microns.  For ISO Class 7, the Fed Std. 209E rating is Class 10,000.  Masks are not used, but wearing cleanroom smocks, booties, hairnets and latex gloves are required antistatic products and carbon-loaded materials are acceptable in this environment.  Extensive use of ionization is concentrated in specific areas.  Heel grounders or booties are acceptable.  Likewise, cross-linked cleanroom specific products are acceptable.  Polyethylene antistatic foams are sometimes used with antistatic-type work carriers.

ISO Class 6 (Fed Std. Class 1000)

An ISO Class 6 cleanroom has no more than 35,200 particles per cubic meter equal to and larger than 0.5 microns.  For ISO Class 6, the Fed Std. 209E rating is Class 1,000.  In an ISO Class 6 cleanroom, full body ESD garments are required with booties utilizing a grounding mechanism as heel grounders or an affixed grounding strip.  Also, static dissipative suits are permissible and used as needed.  Carbon loaded materials are avoided unless the products pass a battery of tests for particle count, outgassing, and chemical compatibility.  Products that enter the cleanroom are cleaned and double bagged prior to being sent into an ISO Class 6 environment. Gloves and facemasks are used.  After only one use, garments must be laundered before reentering an ISO Class 6 cleanroom.  New or laundered garments must be bagged before entrance into the gowning room.  Antistatic products can be used if they pass contamination-generating tests.  Extensive use of ionization is used to reduce particle attraction or to minimize ESD related issues.

ISO Class 5 (Fed Std. Class 100)

An ISO Class 5 cleanroom has no more than 3,520 particles per cubic meter equal to and larger than 0.5 microns.  For ISO Class 5, the Fed Std. 209E rating is Class 100.

Extensive use of ionization is recommended in an ISO Class 5 environment.  A worker is required to wear cleanroom garments that cover his or her body, head, face, hands, and eyes.  An increased number of ionization units can be observed at the workstations and in manufacturing areas.  Contamination-free carbon or amine-free topical antistats are minimally used in an ISO Class 5 cleanroom due to contamination issues.  Inherently conductive polymer-based products are widely utilized due to their humidity independence and ability to be IPA rinsed without losing favorable ESD properties.  Items being introduced into an ISO Class 5 cleanroom are to be cleaned and double bagged, prior to entrance of the gowning room.  Gloves are worn with no skin exposure.  The use of ESD vinyl mats for work surfaces are limited unless the material does not contain antistats with amines that will migrate or transfer onto objects placed onto the surface. Conventional non-cleanroom paper and pens must not be used in this environment.  A company may need to employ one or more full time contamination control engineers to manage both ESD and contamination issues.  Large equipment which is difficult to double bag must be 70% IPA wiped or deionized water bathed before being introduced into the cleanroom.

ISO Class 4 (Fed Std. Class 10)

An ISO Class 4 cleanroom has no more than 352 particles per cubic meter equal to and larger than 0.5 microns.  For an ISO Class 4, the Fed Std. 209E rating is Class 10.  In an ISO Class 4 cleanroom, a full bunny suit with a miniature air circulation unit is required.  Ionization at all workstations and manufacturing centers is considered standard work practice.  The company may employ a full time ESD and contamination control engineer.  Materials must be 70% IPA or deionized water bathed before entrance into the work areas.  The same practices in an ISO Class 5 environment will be employed in an ISO Class 4 cleanroom.  Consumables have more rigid ESD and contamination requirements for use in an ISO Class 4 environment.