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Removing Organic Particles From Photoresist Surfaces

IP.com Disclosure Number: IPCOM000099504D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Dietrich, L: AUTHOR [+4]

Abstract

Suitable excimer laser radiation permits removing organic particles from photoresist layers.

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This is the abbreviated version, containing approximately 67% of the total text.

Removing Organic Particles From Photoresist Surfaces

       Suitable excimer laser radiation permits removing organic
particles from photoresist layers.

      For effectively removing such particles from photoresist
layers, without ablating the latter, short-wave radiation of a very
low energy density but a very high power density is required.  For
this purpose an excimer laser, especially an excimer laser with
ultrashort pulses, is used. The low energy density of the radiation
ensures that there is no ablation of the photoresist layer, whereas
the high radiation power density leads to extreme short-term thermal
heating of the irradiated material and primarily to strong
electrostatic charging of the particles and the substrate material.
As the organic resist material is not ionized by single photon
absorption, say, of KrF excimer laser

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 radiation (248 = 5 eV), it is assumed that this takes place in
multiphoton processes.  As the cross-section of such processes is not
linearly dependent on the radiation intensity and thus the radiation
power density, lasers, such as UV excimer lasers with ultrashort
pulses, are particularly suitable. Experimental Results

      A silicon wafer coated with photoresist was prebaked. Then, the
wafer surface was covered with a large number of latex particles (0.5
mm + 2.0 mm).  This was followed by irradiating the wafer surface
with a KrF excimer laser.  Th...