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Browse Prior Art Database

Nonmetallic Nozzle Plate Assembly for Thermal Ink Jet Printheads

IP.com Disclosure Number: IPCOM000122631D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 4 page(s) / 154K

Publishing Venue

IBM

Related People

Chang, LS: AUTHOR [+4]

Abstract

In the prior art of thermal ("bubble") ink jet printing, there are two basic types of nozzle structures. The first is a channeled-plate configuration superimposed upon the heater array and used for so- called "end-firing" devices. This type has been commercialized and will not be impacted by the present invention. The second printhead configuration is called a "top-shooter", and has been very successfully commercialized. It uses a plate containing an array of nozzles that are positioned directly above a corresponding array of thin film heaters and is separated from the former by polymeric ink flow channels. The alignment between heater die and nozzle plate must be very precise (i.e., to within a couple of microns) to ensure proper printhead performance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Nonmetallic Nozzle Plate Assembly for Thermal Ink Jet Printheads

      In the prior art of thermal ("bubble") ink jet printing,
there are two basic types of nozzle structures.  The first is a
channeled-plate configuration superimposed upon the heater array and
used for so- called "end-firing" devices. This type has been
commercialized and will not be impacted by the present invention.
The second printhead configuration is called a "top-shooter", and has
been very successfully commercialized.  It uses a plate containing an
array of nozzles that are positioned directly above a corresponding
array of thin film heaters and is separated from the former by
polymeric ink flow channels.  The alignment between heater die and
nozzle plate must be very precise (i.e., to within a couple of
microns) to ensure proper printhead performance.  This requirement
makes it difficult to join en masse the large array of heater dies
present on an undiced wafer to a matching array of nozzle plates,
usually produced by electroforming of nickel and plated with gold.
The difficulty arises because processing-induced stresses act to
laterally displace the nozzle plates over the mandrel surface in an
X-Y plane, thus misaligning the parts.  The use of an alternate
double electroforming process to make the nozzle plate (which
incorporates in this case the flow channels eliminating the need for
polymeric flow channels) substantially increases their displacements
and manufacturing costs.  Because of the above and other reasons as
well, the electroformed nozzle plates suffer from a number of
disadvantages, including high manufacturing costs of the plates and
assembly;  potential Ni corrosion due to Au defects; and stress,
deformation, and wetting control problems near the orifici.

      The present invention teaches how to fabricate well-aligned
arrays of high-quality, polymeric nozzle plates directly on the
undiced silicon substrate bearing the heater arrays.  Thus, thin film
heater structures with appropriate passivation layers are first
fabricated, ink vias are then formed, and lastly Au bumps are
(optionally) added to the contact pads.  Ink chamber compartment
walls are then formed in situ from a thick film resist layer on top
of the heater-bearing Si substrate.  At the same time, additional
support posts of thick film resist are formed near the ink via and
die perimeter.  These posts will help support and stiffen the top
polymer layer subsequently.  Thick films that have been successfully
demonstrated include  (Fig.  1). A thin adhesive layer (AL1) is then
deposited on top of the cured thick film resist as well as the
exposed heaters and adjacent surfaces (Fig. 2a).

      On a separate "carrier" substrate (e.g., a glass or silicon
wafer) tha...