Clean Room Cleaning Supplies are as varied and diverse as their applications. There are wipes, sponges, mops and towels. Also grouped together would be disinfectants, wiping alcohol and acetone. Static clean room cleaning supplies include: tacky mats, tacky rollers and shoe cleaners. There is a category of supplies that falls under the equipment umbrella. For example: auto clave (sterilizer), steam cleaners and vacuum cleaners. A classic application for these cleaning supplies is semiconductor manufacturing. Virtually all semiconductor companies perform their semiconductor process in a clean room environment. The need for cleaning supplies is dependent upon that specific environment itself.
Clean room cleaning supplies are only required because of the ubiquitous deployment of clean rooms. It is therefore necessary to understand and appreciate the technology; at least with an overview. Willis Whitfield is accredited with inventing the modern clean room in 1960. As an employee of Sandia National Laboratories, he designed a facility based on constant flow of filtered air. The constant flow pushes airborne particles out of the facility and brings in air through specialized filters. These filters are now known as High Efficiency Particulate Air or HEPA filters. This technology quickly became an integral part of the semiconductor manufacturing process all across the world and remains so today. Obviously this technology has been refined an improved over the years. One of the fundamental steps in development was that of the classification.
Clean room classifications have enabled the semiconductor manufacturer to create a facility that fits the need at hand. The classification is denoted by the number of particles of a certain size in a cubic meter of space in the room. As an example, ordinary room air has 1,000,000,000 particles that are 0.1 microns or larger per cubic meter whereas, a class ISO 1 classification has only 10 particles that are 0.1 microns or larger per cubic meter. See table below for ISO classifications.
Maximum Number of Particles / cubic meter
Class => 0.1 um – 0.2 um – 0.3 um – 0.5 um – 1 um – 5 um
ISO 1 10 – 2.37 – 1.02 – 0.35 – 0.083 – 0.0029
ISO 2 100 – 23.7 – 10.2 – 3.5 – 0.83 – 0.029
ISO 3 1,000 – 237 – 102 – 35 – 8.3 – 0.29
ISO 4 10,000 – 2,370 – 1,020 – 352 – 83 – 2.9
ISO 5 100,000 – 23,700 – 10,200 – 3,520 – 832 29
ISO 6 1,000,000 – 237,000 – 102,000 – 35,200 – 8,320 – 293
ISO 7 10,000,000 – 2,370,000 – 1,020,000 – 352,000 – 83,200 – 2,930
ISO 8 1 E8 – 2.37 E7 – 1.02 E7 – 3,520,000 – 832,000 – 29,300
ISO 9 1 E9 – 2.37 E8 – 1.02 E8 – 3.52 E7 – 8.32 E6 – 293,000
Clean room cleaning supplies are selected based on their ability to perform at the ISO classification required. To this end, the most important characteristic of clean room cleaning supplies is the property of not generating particles, or, that is, generating particles appropriate for the classification at hand. This specific characteristic leads to the selection of the base material used in the manufacture of the cleaning product.
Materials used in the manufacture of clean room cleaning supplies cover a range from organics to synthetics. If we take a look at a specific group of cleaning products, say wipes and sponges, we find a well focused list of materials. These include: paper, cotton, polyester, nylon, cellulose polyester blend, micro fiber and more recently, molded plastics. Paper and cotton products generate most particulates and therefore best suited to less stringent conditions. Next are the nylon, polyester and polyester blended products. These are well suited to the mid range application. For the most stringent of clean room cleaning supplies requirement, the products based on micro fibers and molded plastics are typically preferred.
Another important characteristic of these clean room cleaning supplies is the ability to absorb water and similar fluids. Typical activities that depend upon this property are: mopping up spills, removal of contaminants from critical surfaces and cleaning maintenance of semiconductor process equipment. These activities are performed on a scheduled, or as needed basis. Absorbency is a function of the base material of the: sponge, wipe, mop or towel. The least absorbent of materials are paper and cotton. Also some of these products are one time use only. Next most effective for absorbency are the products based on: nylon, polyester and polyester blends. For the most demanding of tasks, products based on micro fibers and molded plastics are the most superior. In fact some of these products are reported as being able to retain 600% of water by weight.
When considering the specification of clean room cleaning supplies, it is critical to understand the particular environment in which they will be used. This article includes a reference table of classifications that should be consulted as a matter of course. For wipes and sponges, absorbency, cleanliness (lack of particulate generation) and longevity are all important factors that need to be taken into account. There are many other categories of clean room cleaning supplies not detailed here. However, cleanliness (lack of particulate generation), longevity and the intended environment are critical for all.