Xerox Corporation

Diane Atkinson

Cathie J Burke

Mildred Calistri-Yeh

William G Hawkins

Almon P Fisher

Donald J Drake

Michael Robert Campanelli

Herman A Hermanson

Michael C Ferringer

Pamela J Hartman

Daniel O Roll

Methods of patterning resists and structures including the patterned resists are disclosed. A patterned, multi-transmissive mask is used during patterning of resists to control exposure at areas of the resist at which features having different detail are desired. Exposure is varied in more finely patterned and more grossly patterned areas of the resist. The patterned resists have a high degree of topographical uniformity.

Methods of patterning resists and structures including the patterned resists

Patterned photoresist layers formed on substrates have features with high aspect ratios. The photoresist layers can be formed as single layers with aspect ratios as high as about 4:1. In addition, the features in the photoresist layers can have a wide range of aspect ratios in a given single layer. The photoresist layers can be used in ink jet print heads and other devices to provide controlled fluid flow. The photoresist layers are formed using a contrast enhancement material that enables features having substantially vertical side walls and high aspect ratios to be formed.

Method of making inkjet print head with patterned photoresist layer having features with high aspect ratios

Patterned photoresist structures having features with high aspect ratios and method of forming such structures

An ink jet printhead is disclosed which has a heater plate containing the heating elements and driving circuitry means monolithographically formed on one surface thereof and the ink flow directing channel structure is formed on the heater plate using a layer of patternable material, so that all critical alignments are done directly on the heater plate. In one embodiment, the patternable material is a photosensitive polymer which is exposed using a mask to define the channel and reservoir pattern, which is then developed and cured. After curing, the patterned channel structure is polished to provide a smooth coplanar surface and a cover plate with an aperture therein is aligned with a loose tolerance to the channel structure and bonded thereto to complete the printhead. The aperture serves as both ink inlet and a portion of the ink reservoir. The channels are open at one end and serve as the droplet ejecting nozzles, while the other ends are connected to the reservoir. In one embodiment, the cover plate is transparent and the channel structure material is polyimide or polyarylene ether ketone.

Ink jet printhead having a patternable ink channel structure

An ink-jet printhead fabrication technique enables capillary channels for liquid ink to be formed with square or rectangular cross-sections. A sacrificial layer is placed over the main surface of a silicon chip, the sacrificial layer being patterned in the form of the void formed by the desired ink channels. A permanent layer, comprising permanent material, is applied over the sacrificial layer, and, after polishing the two layers to form a uniform surface, the sacrificial layer is removed. Preferred materials for the sacrificial layer include polyimide while preferred materials for the permanent layer include polyarylene ether, although a variety of material combinations are possible.

Method and materials for fabricating an ink-jet printhead

An ink jet printhead has improved resistance to the corrosive effects of ink by coating ink sensitive areas with a photo-imageable benzocyclobutene (BCB) polymer. The BCB can be patterned so as to provide a protective coating over selected areas while leaving other areas uncoated. In one described embodiment, a thermal ink jet printer is formed by bonding together a channel plate and a heater plate. Resistors and electrical connections are formed in the surface of the heater plate. A BCB layer is formed so as to overlie the heater plate to protect the electrical elements while providing pit structure for the heater and for ink flow bypass.

Ink jet printing device

An improved microelectromechanical device, such as a thermal ink jet die or printhead, is formed by the alignment of two planar substrates bonded together by an intermediate thick film layer of patterned polymeric material, such as polyimide. The improved device has a fully cured, patterned thick film layer which is planarized by chemical-mechanical polishing-to improve the bonding strength between the substrates. The planarization removes topographical formations generated during the deposition of the thick film layer and/or during the patterning of the recesses therein.

Micro-electromechanical die module with planarized thick film layer

An improved thermal ink jet printhead is formed by the alignment and bonding of an anisotropically etched silicon wafer channel plate, containing a plurality of channel grooves, to a silicon wafer heater plate, containing a plurality of heating and addressing elements which are covered by a patterned thin and thick film insulating layer. The printhead enables better bonding of the two plates by sequentially patterning each layer of a two layer thick film layer to compensate for topographical features formed in the last thick film layer. The relative thickness and geometrical shapes of the recesses in the two layers are selected, so that topographic formations are varied to prevent standoff between bonded heater and channel plates, thereby insuring that the adhesive applied between the bonded plates will have the greatest propensity to bond.

Ink jet printhead which avoids effects of unwanted formations developed

An improved ink jet printhead is disclosed of the type having a plurality of parallel ink flow channels which terminate with an ink droplet emitting nozzle, a heating element with a cavitational protective layer thereover located in each channel, and MOS electronic circuitry monolithically integrated within the printhead for applying electrical pulses to the heating elements. The pulsed heating elements produce bubbles momentarily on the protective layer of the heating elements which expel ink droplets from the nozzles. The improvement is obtained by providing multi-layer ionic passivation of the MOS electronic circuitry which is exposable to the ink. This is accomplished through the deposition of a multi-layered, thin film insulative coating thereon consisting of a first layer of doped or undoped silicon dioxide having a thickness of 200 .ANG. to 2 .mu.m followed by a second layer of plasma nitride having a thickness of 1000 .ANG. to 3 .mu.m. The silicon nitride is etched from the protective layers of the heating elements and electrical contact pads for external connection to electrical power so that the first layer of silicon oxide is exposed, followed by etching of the silicon oxide to remove it from the protective layer and contact pads. Thus, the MOS circuitry is protected from mobile ions in the ink while the cost effective fabrication of a printhead is maintained. In an alternate embodiment, the multi-layered ionic passivation comprises three thin film layers comprising polyimide interfacing with the ink, followed by silicon nitride, and doped or undoped silicon dioxide directly interfacing with the metallization.

Ink jet printhead having ionic passivation of electrical circuitry

A method for fabricating a coplanar full width scanning array from a plurality of relatively short scanning subunits for reading and writing images. The subunits are fixedly mounted in an end-to-end relationship on a flat structural member with the subunit surfaces containing the scanning elements all being coplanar even though at least some of the subunits have varying thickness. This is accomplished by forming from a photopatternable thick film layer one or more keys on the subunit surface having the scanning elements and associated circuitry and positioning the keys into keyways produced from a photopatternable thick film layer on a flat surface of an alignment fixture. A conformal adhesive bonds a structural member to the assembled subunits to form the full width scanning array.

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Webster, NY, United States of America

Diane Atkinson