Abstract: 12 Methods of forming features in polymeric materials by laser ablation techniques alone, or by the combined use of laser ablation techniques and photolithography, are disclosed. The methods can be used to pattern non-photosensitized materials, as well as photosensitized materials. The patterned features can have different shapes, dimensions and aspect ratios in the same polymer layer. Structures including the patterned features can include multiple layers formed of photosensitized and/or non-photosensitized polymer materials.

Abstract: 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.

Abstract: 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.

Abstract: The new heater element design has a pit layer which protects the overglaze passivation layer, PSG step region, portions of the Ta layer and dielectric isolation layer and junctions or regions susceptible to the cavitational pressures. Further, the inner walls of the pit layer define the effective heater area and the dopant lines define the actual heater area. In alternative embodiments, the dopant lines define the actual and effective heater areas, and an inner wall and a dopant line define the actual and effective heater areas. Further, when the new heater element designs are incorporated into printheads having full pit channel geometry and open pit channel geometry, the operating lifetime of the printhead is extended because the added protection of the pit layer prevents: 1) passivation damage and cavitational damages of the heater elements; and 2) degradation of heater robustness, hot spot formations and heater failures well into the 109 pulse range.

Abstract: 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.

Abstract: The systems and methods of this invention allows for an electrical contact structure of the drop ejecting transducer in an inkjet printhead to be designed in such a way that the relatively thick electrical contact lines are not in the ink drop ejection path between the drop ejector transducer and the corresponding nozzle. Such a design thereby minimizes any visible defects due to misdirected satellite drops.

Abstract: 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.

Abstract: An improved method is disclosed for forming heater elements for an ink jet printhead. The resistance is more closely controlled by doping a central heater region which is formed relatively thinner than the heavily doped heater regions which are used as the gate and contact areas. The thinner central region can doped relatively heavy in order to more accurately adjust the heater resistance.In another embodiment, the thin layer is amorphous silicon rather than the polysilicon to increase the latitude of the energy input.

Abstract: The efficiency of a thermal ink jet printhead is improved by providing a thermally grown field oxide layer and a deposited oxide layer, the two combined layers providing thermal insulation between a resistor layer and a silicon substrate. In a preferred embodiment, zirconium diboride is sputtered in the presence of oxygen to form a thin field oxide layer on a field oxide layer grown on the surface of the silicon substrate. At a predetermined time, during the sputtering process, oxygen is removed and the sputtering continues to form a conductive ZrB.sub.2 layer. The combined thickness of the two oxide layers provides the required thermal isolation between silicon substrate and heater resistor while the thermally grown field oxide layer enables the closer packing of resistor transistor drive circuits.

Abstract: A drive transistor for a high resolution ink jet printhead having a pocket implant in the gate region of the device. The pocket implant enables a reduced source to drain spacing without loss of breakdown voltage. Accordingly, the size of the transistor may be reduced. Alternatively, this device is suitable for addressing 1200 spi resolution printheads. In one embodiment, the pocket implant extends about 1 .mu.m beyond the gate region towards the drain region. Both embodiments produce a graded drift region.

Abstract: In an ejector for a thermal ink-jet printhead, a heating element exposing an area to liquid ink in the printhead includes an insulative layer around the lateral edges thereof, particularly those edges not having conductors associated therewith. This insulation creates a more uniform temperature distribution over the heating area, resulting in a uniform nucleation of a vapor bubble within the liquid ink.

Abstract: The nucleation efficiency of a thermal ink jet printhead is improved by providing a heater resistor with a thin planar oxide film formed over a conductive heater resistive layer. In a preferred embodiment, zirconium diboride is sputtered onto a silicon substrate surface to form a first, electrically conductive base portion of the resistor. At a predetermined time, during the sputtering process, oxygen is introduced to form a thin film of ZrB.sub.2 O.sub.x. The surface of this film is very smooth having a surface roughness of <5 nm RMS.

Abstract: A thermal ink jet printhead is improved by providing a heater resistor which is mechanically isolated from overlying nitride and tantalum layers by growing a thin buffer oxide layer on the surface of the resistor heater layer. The introduction of the buffer oxide layer permits a thinner nitride layer which, in turn, reduces electrical resistance changes which would otherwise be introduced into the resistor arrays by mechanical stress after the nitride layer is deposited.

Abstract: A high voltage MOS transistor, for use in a thermal ink jet printhead, is fabricated with a single, uniformly thick layer of polysilicon that serves as a field plate over the drift region and a gate over the channel region. The fabrication of the drift region and associated drift oxide is performed in a sequence independent of the device channel stop and field oxide fabrication, allowing the drift region to be optimized by varying the thickness of the drift oxide. Using a field plate to increase the breakdown voltage of the device by reducing the concentration of the electric field, the device transconductance is increased by increasing the doping of the drift region without an attendant decrease in breakdown voltage.

Abstract: The nucleation efficiency of a thermal ink jet printhead is improved by forming a heater element with a planar surface. A heater resistor, polysilicon in a preferred embodiment, has an irregular surface which can trap gas or vapors in the cracks or crevices. When the heater resistor is pulsed, the nucleation temperature is reduced by these trapped vapors requiring an increase in electrical input to the resistors, thereby reducing efficiency. The invention recognizes that a heater resistor with a planar surface in contact with an ink layer results in a higher nucleation temperature and increased efficiency. In one embodiment, a phosphosilicate glass (PSG) is flowed directly onto the resistor surface forming a planarization layer. Subsequent deposition of tantalum substantially replicates the underlying topography creating a heater resistor with a smooth surface adjacent the ink.

Abstract: A thermal ink-jet printhead includes ejectors wherein a heating surface is disposed within a channel retaining liquid ink. The heating element within each ejector includes a converter for converting applied electrical energy to heat energy, and a distributor, for distributing the heat energy over a portion of the heating surface. The structure of the heating element allows the effective area of nucleation within the heating area, the size of which directly affects the volume of the ejected liquid ink droplet, to be varied with voltage and/or pulse width.

Abstract: A nozzle plate for ink jet cartridges which are manufactured from a relatively thin film of material, such as, for example, polyimide, polyarylene ether, or composite of a number of materials deposited on a rigid substrate, such as a silicon wafer, and photolithographically processed from the rigid substrate to produce a large quantity of interconnected nozzle plates which may be removed as a sheet of interconnected nozzle plates for ease of handling. The nozzle plates are aligned and bonded to the nozzle bearing front faces of the cartridges.

Abstract: 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 a polybenzoxazole, is applied over the sacrificial layer. After polishing the two layers to form a uniform surface, the sacrificial layer is removed.

Abstract: An ejector for a thermal ink-jet printhead includes a heating element defined on a main surface of a silicon heater chip. A cavity is disposed within the heater chip opposite the side of the heating element exposed to liquid ink. In one embodiment, the heating element is disposed on a narrow pillar which is surrounded by two elongated trenches. In another embodiment, the heating element is suspended over a cavity by narrow supports. In each case, the cavity reduces the thermal mass of the structure supporting the heating element and acts as an insulator to prevent excess heat from being dissipated into the body of the heater chip.

Abstract: 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.