The Causes of Cleanroom Contamination

Many products require manufacturing in a cleanroom or controlled environment. The science of micro-contamination and cleanrooms is important for yield and reliability of these products such as batteries, medical devices, pharmaceuticals, optical devices, consumer electronics assemblies, and food processing are just a few examples of products that require a high level of cleanliness in the manufacturing environment. Human beings are the most prevalent contaminant carrier of all listed threats. There are many possible sources of contamination of the cleanroom environment. Equipment, physical facilities, and exposed surfaces can produce particles through simple operational activities such as friction, heat, exhaust, outgassing, and static electricity. Delivered production components may also introduce contaminants but it is still the workers in the cleanroom that generate the most particles. They are the easiest to manage, yet contribute to the most contamination.

While non-particulate contamination (non-volatile residue or airborne molecular contamination, for example) is a concern in many applications, the fundamental aspect of the cleanroom environment is an effective cleanroom management program that keeps the environment free of airborne particles. As cleanroom operators are working, they generate millions of particles with every movement. Schlieren thermal images show particles emitted from the human body. Particles migrate up through the cleanroom apparel toward the head and fall down the legs during cleanroom activities.

Bacteria, molds, and yeast are viable organisms which are chemically active. Byproducts of their growth and replication can cause a variety of contamination in the cleanroom, based on the nature of the chemicals released during generation. Humans also release elemental chemicals that can cause contamination: Spittle: potassium, chloride, phosphorus, magnesium, and sodium. Dandruff: calcium, chloride, carbon, and nitrogen. Perspiration: sodium, potassium, chloride, sulphur, aluminium, carbon, and nitrogen. Fingerprints: sodium, potassium, chloride, and phosphorus

As mentioned earlier, any activity by the cleanroom operator generates millions of viable and non-viable particles. Preventing these contaminants from entering the cleanroom environment is the main objective. It requires a commitment by everyone entering the cleanroom to make it happen. Professional cleaning personnel must be aware of the importance of controlling contaminant. It is very important to limit conversations and actions such as running and prohibit other non-professional activities in the cleanroom to only those required for the manufacture of the product.

As mentioned earlier, any activity by the cleanroom operator generates millions of viable and non-viable particles. Consequently, it is imperative to limit talking and actions in the cleanroom to only those required for the manufacture of the product. Running, horseplay, and other non-professional activities are not permitted. Other behavioural requirements include, but are not limited to, the following: Smoking is not allowed inside the manufacturing facility including all cleanroom areas. Smokers release Tar particles for at least one-half hour after smoking one cigarette. Nothing is allowed inside the cleanroom complex which is not required in the cleanroom manufacturing process. This includes personal items such as jewellery or keys, cosmetics, tobacco or matches in any form, and food or drink in any form. Hair may not be combed in the cleanroom gowning area. Only cleanroom compatible ball-point pens are allowed inside the cleanroom for recording data on cleanroom compatible paper and clipboards. While working in the cleanroom, mannerisms such as scratching or hand-rubbing are not allowed. Cleanroom personnel may not access the inside of the cleanroom uniform. The use of facial tissues is prohibited in the cleanroom. If one must use a cleanroom compatible non-linting tissue, it must be used only in the gowning area and disposed appropriately in waste receptacle. All doors must remain closed when not entering or exiting. Emergency doors may be alarmed with a visual and audible alarm to enforce compliance.

We hope that this article has provided you with insights of why and how people are considered to be the number one supplier of cleanrooms contamination.

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