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Temporary Substrate for Selective Wet-Dry Etching Thermal Printhead

IP.com Disclosure Number: IPCOM000106232D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+4]

Abstract

Using a wet-etchable heat conductive metal temporary substrate permits the use of high temperature preferential dry etching to produce high resolution tungsten for thermal printheads.

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Temporary Substrate for Selective Wet-Dry Etching Thermal Printhead

      Using a wet-etchable heat conductive metal temporary substrate
permits the use of high temperature preferential dry etching to
produce high resolution tungsten for thermal printheads.

      Figs. 1-5 show the transfer process for patterning tungsten (W)
on a temporary substrate, using high-temperature dry etching (plasma
etching or reactive ion etching) of the tungsten for resolution, and
thereafter laminating the tungsten pattern to a polyester permanent
substrate.  The polyester permanent substrate is not used during dry
etching because the laminating adhesives do not withstand the high
etching temperatures.

      Fig. 1 shows the starting blank of tungsten sheet 1, deposited
over chrome adhesion layer 2 on temporary copper substrate 3, covered
by a second chrome adhesion layer 4, nickel mask film 5 and
photoresist layer 6.

      Fig. 2 shows optical lithography and wet etching of the nickel
mask film 5 to define the pattern desired in the tungsten sheet 1.

      Fig. 3 shows the result of the dry etch, a pattern of tungsten
1 on copper temporary substrate 3.  Traces of nickel mask film 5 and
chrome adhesion layer 4 may be left on the surface of the tungsten 1
after dry etching.  These traces may remain; they aid in heat
conduction away from the electrode tip after print intervals.

      Fig. 4 shows the lamination of permanent polyester substrate 7
with adhesive 8 on...