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This invention aims at maintaining gas purity by using two cleanrooms. One cleanroom is used to store the gas supply pipe that extends from a storage tank. The other cleanroom houses gas containers that are fed by gas filling pipes. When the gas-filling pipes are not in use, ultra-high purity nitrogen gas flows, maintaining an extremely clean state inside of the pipes.
Patent number: 5,937,918
Date granted: August 17, 1999
Inventors: Mitauhide Takeharada and Shigeyoshi Nozawa, Teisan K.K. (Tokyo)
Cleanroom mop head
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Cleaning strings dangle from an attachment rod like those of a common string mop. Like many cleanroom mops, the cleaning strings are made of polyvinylalcohol (PVA). Cleaning strings have a curved free end to minimize tearing. The mop head has a base portion, a first and a second surface as well as edges between those surfaces. At least one of the two edges is substantially non-linear, which increases the exposure of absorbent material beneath the PVA, which increase the amount of liquid that is picked up and ultimately drained. Non-linear edges also increase contact pressure, which the inventor says, increases cleaning performance, and are longitudinally flexible for increased durability.
Patent number: 5,884,355
Date granted: March 23, 1999
Inventor: Joselito De Guzman, Micronova Manufacturing Inc. (Torrance, CA)
Filtration efficiency
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Based on the filtration efficiency of the materials used, the useful life of dust-free clothes worn by cleanroom operators can be determined, according to the inventors. A piece of garment material is placed inside this apparatus. A gas ionizer removes static in the chamber, where particles are generated and counted while a humidifier creates water vapor. The generator and counter also bring in and tally particles before and after they pass through the test item. Filtration efficiency is determined by counting the particles introduced into the chamber and the particles that pass through a sample of cloth material.
Patent number: 5,939,617
Date granted: August 17, 1999
Inventors: Chang-su Lim, Hyun-joon Kim and Youn-soo Han, Samsung Electronics Co. Ltd (Suwon, Korea)
Hypoxic cleanroom
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The system employs a gas-recycling unit, which draws a gas mixture from the cleanroom and sends it back through a perforated ceiling, producing a laminar flow inside. The enclosure with an anteroom is hermetically closed to the outside atmosphere by an airtight door, equipped with pressure-release valves. The enclosure and anteroom are made of clear vinyl, glass or plastic panels that can be installed in any cleanroom. Both have access strip doors attached to a metal frame with free-hanging flexible, clear vinyl. An air-separation unit is connected to the enclosure by conduit, through which the oxygen-depleted air flows. The unit takes ambient air through an intake filter and separates it into an oxygen-enriched fraction that is disposed of through an outlet on the unit, while the depleted portion flows through conduit to the inside of the enclosure.
Patent number: 5,887,439
Date granted: March 30, 1999
Inventor: Igor K. Kotliar, Hypoxico Inc. (New York, NY)
Cleanroom for semiconductor devices
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In this cleanroom, various apparatuses for semiconductor manufacturing are arranged on the floor. Clean air is blown from the ceiling side of the manufacturing space. Air is returned to the area under the floor through the ventilating aperture for circulating the air. The transfer route for moving precursors of semiconductor devices between each facility is provided in the air returning area under the floor, which returns air in the manufacturing space. Feeding of the precursors between the transferring system and manufacturing space can be executed through the aperture in the floor.
Patent number: 5,929,077
Date granted: July 27, 1999
Inventor: Toshiro Kisakibaru, Sony Corp. (Tokyo)
Sealed lighting unit
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Designed to prevent or decrease leakage of filtered, conditioned air from a cleanroom, this adapted light source also prevents or decreases infiltration of unfiltered, contaminated air from the space above the ceiling. It includes a housing to support one or more light sources and a impermeable light diffuser mounted to the housing. A gasket joins perimeter surfaces of the frame and the ceiling opening. A thumbscrew supports the unit, which seals it to the ceiling opening.
Patent number: 5,934,786
Date granted: August 10, 1999
Inventors: Donald O'Keefe (Wyoming, MI)
Send your inventions
Information on the patents highlighted above was obtained through the U.S. Patent and Trademark Office. Inventors who have been granted patents within the last six months for new cleanroom and contamination technology are encouraged to submit them to CleanRooms magazine for publication. Send a brief description of the invention along with a detailed drawing to Mark A. DeSorbo, associate editor, CleanRooms, 98 Spit Brook Road, Nashua, NH 03062, or e-mail at [email protected].