Browse Prior Art Database

Novel Edge Bead Removal Process

IP.com Disclosure Number: IPCOM000122313D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 53K

Publishing Venue

IBM

Related People

McIntyre, T: AUTHOR [+3]

Abstract

Disclosed is a novel process for removing the bead of photoresist from the edge of a wafer during the develop process.

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This is the abbreviated version, containing approximately 100% of the total text.

Novel Edge Bead Removal Process

      Disclosed is a novel process for removing the bead of
photoresist from the edge of a wafer during the develop process.

      An unavoidable side effect of spinning photoresist onto a wafer
is the build up of a bead of resist on the wafer's edge due to
surface tension.  Normally, this bead is removed at the apply step
with a solvent rinse.  Removal is desirable to avoid mechanical
damage to the edge resist and contamination of the wafer surface.

      This new technique utilizes ultraviolet light channeled through
a light pipe to expose the resist at the edge of a spinning wafer.
This takes place as the first program step in the develop tool and
takes only about 10 seconds total. During the step, a light pipe or
fiber optic bundle is lowered very close to the surface of the wafer.
The UV light source is turned on and the wafer rotated underneath the
light pipe exposing the resist at the edge of the wafer. At this
point, the product wafers have already been through the normal expose
and post expose bake steps and are ready for develop.  Immediately
after the edge expose step, while still on the vacuum chuck, the
wafers are then spray developed using the normal process, FIG. 1.
During develop, the normal pattern is defined as well as the unwanted
edge resist being removed from the wafer.  No additional solvents are
used and that chemical expense is saved.

      Disclosed anonymously.