A method and a wiper for reducing particulate contamination which otherwise might result from the use of the wipe in a controlled environment, such as that maintained in a cleanroom, the wiper being of the type constructed at least partially from a thermoplastic fabric material by severing the wiper along peripheral edges thereof from a sheet of such material having indeterminate dimensions, the method and the wiper providing a fused border in the material along the peripheral edges of the wiper and extending inwardly into the wiper a distance great enough to provide the fused border with sufficient area and sufficient tear-strength to maintain therein segments of the material of the wiper which otherwise might be released from the peripheral edges of the wipe during use of the wiper, yet small enough to maintain pliability and absorbency in the wiper for wiping procedures. In one embodiment of the wiper, two outer plies of the material are joined along the fused border to establish a sealed envelope within which is placed an inner ply of absorbent material isolated from the controlled environment by the outer plies of material and the fused border.
The product relates generally to the prevention of particulate contamination in cleanrooms and pertains, more specifically, to the construction of wipers for use in a cleanroom, or another similar controlled environment, the construction being such that the wipers will not release contaminating particles into the controlled environment.
Cleanrooms are finding wider use in the manufacture, inspection and maintenance of precision products where it is essential that various operations be conducted in an environment as free of undesired small particles as possible. Cleanrooms can function effectively only when every effort is taken to maintain the close control necessary to preclude contamination of the controlled environment within the cleanroom. Such contamination most often is generated by the worker in the cleanroom and by items brought into the cleanroom. Rigorous standards have been established, and continue to be developed, for the operation of cleanrooms in such a manner as to exclude unwanted contaminants from the controlled environment. One potential source of particulate contamination in cleanrooms has been the wipers used extensively in connection with operations carried out in the controlled environment of a cleanroom. For example, in the fabrication of semiconductor wafers, wipes are used for cleaning up spills which can occur during the procedures carried out in the controlled environment of a cleanroom. In addition, wipers are used for wiping surfaces of various equipment and items in the cleanroom, as well as for wiping down the walls and other interior surfaces of the cleanroom itself. The very nature of a wiper, which requires a high degree of absorbency and pliability, militates against a construction which resists shedding and the concomitant release of small particles into the surrounding environment.