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Fast Laser-Steam Cleaning by Continuous Liquid-Film Deposition and Pulsed Laser Irradiation of a Moving Surface

IP.com Disclosure Number: IPCOM000117525D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Ayers, GA: AUTHOR [+6]

Abstract

Disclosed is an apparatus for high throughput laser steam cleaning of surfaces. A part to be cleaned, (1) in Fig. 1, is moved continuously as a thin liquid film (2) is continuously deposited on its surface using a nozzle, (3). The liquid film is approximately 1 mu m thick. Pulsed laser radiation (4) is applied downstream to superheat the liquid film, producing cleaning action. A typical embodiment uses a KrF laser pulsed at 5 to 20Hz with a 1mm/sec translation speed for the part. The maximum laser pulse rate of 20Hz is limited by the rate at which the thin liquid film can be replenished. In another embodiment, use of "multiplexed scanning" provides a higher throughput (Fig. 2).

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Fast Laser-Steam Cleaning by Continuous Liquid-Film Deposition and
Pulsed Laser Irradiation of a Moving Surface

      Disclosed is an apparatus for high throughput laser steam
cleaning of surfaces.  A part to be cleaned, (1) in Fig. 1, is moved
continuously as a thin liquid film (2) is continuously deposited on
its surface using a nozzle, (3).  The liquid film is approximately 1
mu m thick.  Pulsed laser radiation (4) is applied downstream to
superheat the liquid film, producing cleaning action.  A typical
embodiment uses a KrF laser pulsed at 5 to 20Hz with a 1mm/sec
translation speed for the part.  The maximum laser pulse rate of
20Hz is limited by the rate at which the thin liquid film can be
replenished.  In another embodiment, use of "multiplexed scanning"
provides a higher throughput (Fig. 2).

      A high repetition rate (300Hz) KrF laser is scanned
perpendicularly to the direction of the part motion in a sawtooth
pattern using a galvanometer mirror.  Replenishment of the micron
thick liquid film is provided by an elongated nozzle or an array of
nozzles (*).
  Reference
  (*) P. E. Ross, "Dust Busters: Laser Wipe Submicron Motes From
       Silicon Wafers," Scientific American 262, 6, 86-88 (1980).