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Thermal Ink Jet Heater Devices Incorporating Diamond-Like Carbon Films As Protective Overcoats

IP.com Disclosure Number: IPCOM000120972D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 91K

Publishing Venue

IBM

Related People

Stasiak, J: AUTHOR [+5]

Abstract

A novel thermal ink jet (TIJ) heater device is disclosed, which incorporates a diamond-like carbon (DLC) film. This film is used to electrically isolate and protect the critical component of the device structure, a thin film resistor, from exposure to the corrosive ink which is used in current thermal ink jet printers.

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Thermal Ink Jet Heater Devices Incorporating Diamond-Like Carbon
Films As Protective Overcoats

      A novel thermal ink jet (TIJ) heater device is disclosed,
which incorporates a diamond-like carbon (DLC) film.  This film is
used to electrically isolate and protect the critical component of
the device structure, a thin film resistor, from exposure to the
corrosive ink which is used in current thermal ink jet printers.

      Thermal ink jet device physics, device fabrication, reliability
and failure mechanisms and the operation of printers using this
technology have been described in detail elsewhere [1,2].  Inks which
are currently used in these printers have been shown to oxidize
and/or etch the thin film resistor metal.  Prolonged exposure to ink
ultimately leads to device failure.  The present TIJ devices are
fabricated using two to three overcoat films which are necessary to
protect the delicate thin film resistor from exposure to ink.  The
ideal overcoat material must be nonporous, chemically inert to ink
solutions, conformal and demonstrate uncompromised adhesion to the
structure it is protecting.  Furthermore, to insure that the device
operates properly, the material must be electrically insulating and
offer high thermal conductivity.  The material that is currently used
by different manufacturers in thermal ink jet heater structures with
less than ideal results is amorphous silicon carbide (a-SiC:H).
Typically, the carbide is plasma-deposited on a starting layer of
amorphous silicon nitride (a-SiN:H) or blended in situ during
deposition to produce a graded blend of nitride and carbide.  This
dual insulator layer offers a reduced exposure to pinholes and other
layer-specific defects.  Unfortunately, recent experiments and
accelerated lifetime studies have indicated that these films do not
provide sufficient protection to meet the lifetime criteria required
of TIJ print-heads.

      The central idea of this article is to replace the
n...