Browse Prior Art Database

Beam Delivery System Employing Shadow Correction for Excimer Laser Wirestripping

IP.com Disclosure Number: IPCOM000101057D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 85K

Publishing Venue

IBM

Related People

Brannon, J: AUTHOR [+4]

Abstract

Disclosed is an improved beam delivery system for use in excimer laser wirestripping systems. It effectively removes the problem of ghosting and image inversion when the light is reflected back to remove the insulation on the side of the wire opposite to the primary illumination direction. If not corrected, these problems result in incomplete insulation removal. A simple optical system is described consisting of a lens and appropriately positioned mirror to reflect the light back onto the insulation without optical inversion, ensuring complete insulation removal.

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Beam Delivery System Employing Shadow Correction for Excimer Laser Wirestripping

       Disclosed is an improved beam delivery system for use in
excimer laser wirestripping systems.  It effectively removes the
problem of ghosting and image inversion when the light is reflected
back to remove the insulation on the side of the wire opposite to the
primary illumination direction.  If not corrected, these problems
result in incomplete insulation removal.  A simple optical system is
described consisting of a lens and appropriately positioned mirror to
reflect the light back onto the insulation without optical inversion,
ensuring complete insulation removal.

      In a typical excimer laser wirestripping embodiment, an
illuminated rectangular aperture is imaged by a single lens onto the
front side of a small diameter wire containing plastic insulation
which is to be removed.  Fig. 1 shows the detail of the laser
beam/wire geometry.  The wire is set at an angle with respect to the
rectangular orientation of the beam.  As the light traverses past the
wire, a geometric shadow is created in the beam where it interacted
with the front and sides of the wire, causing insulation removal. The
light continues to a spherical mirror which reflects and re-images
the beam onto the back side of the wire where the remaining
insulation is stripped.  Due to optical inversion, however, the
shadow is imaged onto the backside at the opposite angle of the wire.
The laser illumination...