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Lift-Off Stencil for Resistive Ribbon Print Head

IP.com Disclosure Number: IPCOM000119391D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+4]

Abstract

A problem that exists in resistive ribbon thermal transfer printing is the high rate of print head wear. This wear occurs when printing is done at high speed. It is due, in part, to the increased current required when printing at these higher speeds. Thin film heads using hard films, such as TiN, TiC, WC, and W are difficult to fabricate because these films are not easily chemically etched, and wet etching is not easily controlled due to lateral undercutting. Also wet etching has many safety and environmental restrictions, as well as high costs. This article describes a way of using a dry process, oxygen reactive ion etching (RIE) or plasma etching, that is compatible with semiconductor processing, provides a "lift-off" stencil for thick metals, eliminates wet chemical processes, is inexpensive, and batch processable.

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Lift-Off Stencil for Resistive Ribbon Print Head

      A problem that exists in resistive ribbon thermal
transfer printing is the high rate of print head wear.  This wear
occurs when printing is done at high speed.  It is due, in part, to
the increased current required when printing at these higher speeds.
Thin film heads using hard films, such as TiN, TiC, WC, and W are
difficult to fabricate because these films are not easily chemically
etched, and wet etching is not easily controlled due to lateral
undercutting.  Also wet etching has many safety and environmental
restrictions, as well as high costs.  This article describes a way of
using a dry process, oxygen reactive ion etching (RIE) or plasma
etching, that is compatible with semiconductor processing, provides a
"lift-off" stencil for thick metals, eliminates wet chemical
processes, is inexpensive, and batch processable.

      The process incorporates a bi-level layering technique. Dupont
2566 polyimide layer 10 is spin-coated onto a resist substrate 12
(KAPTON*) and cured to about 230oC.  The thickness of the polyimide
can be controlled by both the spin speed and the viscosity. Films of
polyimide can be spin-coated to 10 to 15 microns thick.  A layer 14
of TNS photoresist is then spun on the cured polyimide, imaged and
patterned using standard photolithography and solvents.  Once the
pattern has been defined, the top resist layer 14 is modified by
diffusing in silicon, and becomes a silyated novalac re...