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Browse Prior Art Database

Continuously Variable Optical Defocus System for Laser Ablation Edge Profile Control

IP.com Disclosure Number: IPCOM000115587D
Original Publication Date: 1995-May-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Doany, FE: AUTHOR [+2]

Abstract

Disclosed is an optical system for precisely controlling the edge profiles (wall angles) produced by laser ablation of features in polymers, ceramics, metals, or semiconductors. The optical system is used to continuously vary the extent of defocus during an exposure. This allow etching of features with edge profiles that are not simple one-angle walls but continuously varying shapes. For example, ink-jet nozzles require smooth "trumpet"-shaped features in order to achieve turbulence-free liquid flow out of the nozzles.

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Continuously Variable Optical Defocus System for Laser Ablation Edge
Profile Control

      Disclosed is an optical system for precisely controlling the
edge profiles (wall angles) produced by laser ablation of features in
polymers, ceramics, metals, or semiconductors.  The optical system is
used to continuously vary the extent of defocus during an exposure.
This allow etching of features with edge profiles that are not simple
one-angle walls but continuously varying shapes.  For example,
ink-jet nozzles require smooth "trumpet"-shaped features in order to
achieve turbulence-free liquid flow out of the nozzles.

      The optical system in its simplest embodiment consists of a
pair of optically transparent wedged substrates (discs) that are
inserted between the mask and lens or between the lens and sample in
an optical projection system.  The two discs have identical wedges
and are fabricated using optically transparent material, such as
fused silica.  The two wedges are aligned together to produce a
plane-parallel plate as seen in Fig. 1(a).  The two discs are placed
in a mount that allows translation of one disc relative to the other
along the wedge direction, as seen in Fig. 1(b).  This motion will
produce a change in the thickness while maintaining the
plane-parallel nature of the system.  The plane-parallel plate in the
optical path will produce a defocus in the image.  The amount of
defocus will depend on the thickness of the plate, which can be
varied...