Inventor's corner
09/01/2002
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 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, Clean Rooms, 98 Spit Brook Road, Nashua, NH 03062, or e-mail at [email protected].
Wafer surface cleaning
The invention includes a film-forming chamber (A) for wafers (B). A process gas feed line (C) connected to the chamber (A) supplies process gas used to form a film on the wafer. A hydrogen gas feed line (D) is provided to clean the wafers and includes a mass flow and valve controller (E, F) to control gas flow. The chamber also includes a filament (G) to heat the hydrogen gas as well as a vacuum pump (H) to clear the chamber. In semiconductor wafer processing, hydrogen gas is introduced into the same chamber used for film formation and heated to generate hydrogen radicals. Alternatively, plasma is applied to generate hydrogen radicals, or the semiconductor wafer is heated immediately before film formation. Thereby, contaminants on the surface of the wafer are removed. Thereafter, a conductive film or an insulating film is formed on the wafer in the same chamber.
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6,410,454 B1
June 25, 2002
Seiji Muranaka, Cozy Ban and Akihiko Osaki, of Mitsubishi Denki Kabushiki (Tokyo).
Laser ventilation system
The industrial laser ventilation system can minimize the cooling air intake required during normal operation, according to the inventors. Adequate ventilation is maintained even if the housing is opened. Various sensors monitor the condition of the cooling air and can increase the air intake if required for cooling or safety. Such a ventilation system is particularly ideal for excimer lasers in microlithography applications because the consumption of conditioned cleanroom air is controlled by the actual needs of the laser device. The laser housing (A) encloses all major laser components, including the laser discharge unit (B), the gas and cooling water utilities (C), electric utilities (D) and electronic control modules (E). The housing has several air inlets (F) and at least one air outlet or exhaust port (G). Exhaust flow rate, according to the inventors, is typically 200 cubic meters per hour, and internal vanes and baffle plates (H) guide air to cool heat-generated components efficiently.
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6,414,828 B1
July 2, 2002
Kay Zimmerman and Ulrich Rebhan of Lambda Physik AG (Goettingen, Germany).
Polishing system
The substrate processing system has a factory interface module (A), a chemical mechanical polishing carousel (B) outfitted with polishing pads (C) and a transfer station (D), a cleaner (E), a particle monitor (F) and a substrate transfer system (G). The factory interface module includes a chamber storage station (H) to hold a plurality of substrates (I) in a horizontal position. In a normal polishing operation, an unpolished substrate (I) is retrieved by the factory interface robot (J) from one of the four cassettes (K). The factory interface robot (A) "picks" up the wafer with vacuum suction and transports it through an entry port (L) to the staging section (M). There, the wafer is placed in either the pass-through support (N) or a buffer (O). The wet robot (P) then extracts the wafer from the staging section and places it in the transfer station of the polisher. From there, it is chemically and mechanically polished by one of the four polishing stations. After polishing, the wet robot (P) transports the wafer from the transfer station of the polisher to the walking beam (R) in the cleaner (E). The walking beam transports the wafer through the cleaner, where slurry and other contaminants are removed. The factory interface module then removes the wafer from the cleaner through an exit port (S), inserts it into the particle monitor and returns it to one of the cassettes.
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6,413,145 B1
July 2, 2002
Jay D. Pinson II and Arulkumar Shanmugasundrum, of Applied Materials Inc. (Santa Clara, CA).
Wafer cleaning device
A device for cleaning semiconductor wafers with a cleaning liquid includes a cleaning station with a plurality of rotating pairs of rollers that are arranged one behind another and to which the cleaning liquid is applied. A set of rollers is formed by a top roller (A) and a bottom roller (B), while the semiconductor wafer (C) moves between the top and bottom roller layers. This also serves as a conveyor for moving the semiconductor wafer to and from the cleaning station. A film of cleaning liquid (D) from feed pipes (E) is supplied from a container (F). The cleaning agent flows over the top rollers in the form of a falling liquid, which migrates over the rollers.
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6,412,500
July 2, 2002
Roland Brunner, Franz Sollinger, Hans-Joachim Luthe and George-Friedrich Hohl, of Wacker Siltronic Gesellschaft fur Halbleitermaterialien (Burghausen, Germany).
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