Abstract: A system controls an ink jet printing apparatus for propelling ink jet droplets on demand from a printhead having a plurality of drop ejectors. In the printhead, each ejector includes a heating element actuable in response to electrical input signals, each input signal having an amplitude and a time duration, selectably applied to the heating element to produce a temporary vapor bubble and cause a quantity of ink to be emitted for the creation of a mark on a copy sheet. The temperature of ink in the printhead is sensed, and a combination of power level and time duration of the electrical input signal for the heating element to result in a desired size of the mark of the copy sheet is selected, by entering the sensed temperature of the ink into a predetermined function relating the energy of the electrical input signal to the corresponding resulting size of the mark on the copy sheet.

Abstract: A thermal ink jet printhead has an outer, metallic hydrophobic coating on its front face to repel ink. Eliminating the accumulation of ink at the nozzles of the printhead allows an ink droplet to be accurately ejected and ensures the directionality of the ejected ink droplet onto the printing medium. The outer coating is formed of a metal selected from the group of noble metals, including gold, platinum, palladium, silver, rhodium and ruthenium. An adhesion layer is preferably deposited between the front face of the printhead and the outer ink-repellent coating. The metallic coating is preferably applied by electroplating, wet electroless plating, evaporation, sputtering, ion plating, CVD or plasma CVD.

Abstract: A precision etched, three dimensional device is fabricated from a silicon wafer by etching from one side of the wafer. A chemical masking layer, such as silicon nitride, is first deposited on all sides of the wafer, followed by the deposition of a robust mechanical layer, such as polycrystalline silicon, over the masking layer on all sides of the wafer. The two layers are sequentially patterned on one side of the wafer and then the wafer is placed into an etchant bath which etches the exposed surface of the wafer and concurrently removes the protective layer, leaving a defect-free masking layer that prevents unintentional etching that would reduce yields of fabricated devices.

Abstract: A resistive heating element is formed by depositing an amorphous silicon film on selected portions of a substrate and heating the deposited amorphous silicon film so that it undergoes solid phase epitaxy to form a (111) textured polycrystalline silicon film. The method is particularly useful for forming electro-thermal transducers for thermal ink jet printheads.

Abstract: An integral filter is fabricated by patterning a layer of etch resistant material on one side of a (100) silicon wafer to produce an array of equally spaced, uniformly sized posts or shapes and doping the exposed surface of the wafer by boron ion implant. The dopant is diffused into the wafer while the array of posts of etch resistant material masks the diffusion under them. The size of the posts or shapes determines the undoped areas of the wafer and, thus, the mesh size of the eventually produced integral filter. The wafer is recoated with a layer of etch resistant material and the other side, which was not doped, is patterned to form a plurality of sets of elongated channel vias and reservoir vias, one reservoir via for each set of channel vias.

Abstract: An ink jet printhead having an integral membrane filter fabricated over the surface of the printhead containing the ink inlet is disclosed. The individual printheads are obtained by a sectioning operation which cuts aligned and bonded channel and heater wafers. The mated wafers contain a plurality of printheads and must be separated. The integral membrane filter is formed on the channel wafer after it is anisotropically etched incorporating the etch resistant mask layer and prior to mating with the heater wafer. A patternable layer is deposited over the etch resistant masking layer and exposed, patterned and developed to establish the mesh filter. In one embodiment, the side of the channel wafer not patterned and etched is heavily doped to form an etch stop which increases the robustness of the membrane filter by ensuring that the masking layer remains intact during subsequent fabricating steps.

Abstract: In semiconductor technologies such as thermal ink jet printhead fabrication, there exists a need for the precise placement of channels in a substrate. Due to errors in plane alignment in semiconductor substrates, channel structures tend to widen dimensions, thus lowering precision. A one-step anisotropic etching process is disclosed for accurately making channel structures, as well as reservoir structures. Channel structures are formed by segmenting the channel, such that during the anisotropic etching, thin walls between the segments break down before the completion of the etch. Widening of channels is greatly reduced, thus increasing precision. During such a one-step process, larger structures, such as a reservoir, can be formed during the same step.

Abstract: A transducer for a thermal ink jet printhead has a primary heating region having a tantalum layer, a silicon nitride layer and a polysilicon resistor layer. An n.sup.- drift layer resistor serves as a secondary heating region and a field layer of silicon dioxide acts as an insulator. The field layer is sandwiched between the primary heating region and the secondary heating region. The secondary heating region by heating the field layer causes the heat generated in the primary heating region to be directed toward ink which lies above the primary heating region. An electrical contact connects the polysilicon resistor layer of the primary heating region to a driving transistor located on the same silicon wafer as the transducer. The driving transistor has a field oxide layer sandwiched between an n.sup.- drift layer and a field plate layer, the field plate layer causing secondary pinch off of the n.sup.- drift layer thus enabling higher operating voltages.

Abstract: A thermal jet ink printing is provided with an improved printhead. The printhead is formed by monolithic integration of MOS logic elements and drivers onto the same silicon substrate containing the resistive elements using a more efficient manufacturing process. In a preferred embodiment, the logic switches, logic drivers and resistive elements are formed from a single layer of polysilicon with the resistive element formed on a thermally grown field oxide layer. The integrated circuit chips are formed by a MOS fabrication technology which uses fewer processing steps than used in existing chips, and the resulting chips are thermally stable and can be operated at higher logic voltages.

Abstract: A multi-color roofshooter type thermal ink jet printhead includes a common heater substrate having at least two arrays of heating elements and a corresponding number of elongated feed slots, each heater array being located adjacent its corresponding feed slot. A common channel substrate is layered above a heater substrate and includes arrays of nozzles corresponding in number to the arrays of heating elements, each nozzle array communicating with one of the feed slots on the heater substrate. Each nozzle array is isolated from an adjacent nozzle array and each nozzle of each nozzle array is aligned above a respective heating element of a corresponding heater array. Each of the heater arrays is individually addressed and driven by switching circuitry located on the heater substrate adjacent to its corresponding heater array. The switching circuitry can be active driver matrices corresponding in number to the arrays of heating elements.

Abstract: 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.

Abstract: Disclosed is a method of fabricating a precision etched, three dimensional device from a silicon wafer, wherein the etching is done from one side of the wafer using a two step silicon etching process. A two-sided deposition of a robust protective layer, such as polycrystalline silicon, is placed over a two-sided deposition of a chemical masking layer such as silicon dioxide. The two layers are concurrently patterned with first and second sets of vias on one side of the wafer, while the opposite side is protected by the protective layer. The protective layer is removed to permit deposition of a second masking layer such as silicon nitride, followed by deposition of a second protective layer. Again, the second protective layer prevents damage to the fragile second masking layer on the wafer backside while its frontside is patterned with a similar set of vias aligned with the first set of vias in the first masking layer.

Abstract: A "roofshooter" pagewidth printhead for use in a thermal ink jet printing device is fabricated by forming a plurality of subunits, each being produced by bonding a heater substrate having an architecture including an array of heater elements and an etched ink feed slot to a secondary substrate having a series of spaced feed hole openings to form a combined substrate in which said series of spaced feed hole openings communicates with said ink feed slot, and dicing said combined substrates through said ink feed slot to form a subunit. An array of butted subunits having a length equal to one pagewidth is formed by butting one of said subunits against an adjacent subunit. The array of butted subunits is bonded to a pagewidth support substrate.

Abstract: At least one through opening of predetermined location and dimensions is fabricated in a (100) silicon wafer by orientation dependent etching method after completion of integrated circuits on the wafer, the opening extending through the wafer between a circuit surface of the wafer and an opposite parallel base surface of the wafer and having a predetermined location relative to the integrated circuit on the circuit surface of the wafer.

Abstract: A thermal ink jet printhead is improved by a specific heating element structure and method of manufacture. The heating elements each have a resistive layer, a high temperature deposited plasma or pyrolytic silicon nitride thereover of predetermined thickness to electrically isolate a subsequently formed cavitational stress protecting layer of tantalum thereon. The pyrolytic silicon nitride permits wet chemical or dry plasma etching delineation of the tantalum without deleterious impact on the silicon nitride, while the delineated tantalum can serve as mask for the wet etch delineation of the silicon nitride. Because of the high deposition temperatures, the aluminum electrodes are patterned and passivated last. Such a construction lowers the manufacturing cost and concurrently provides a more durable printhead.

Abstract: A thermal jet ink printing system is provided with an inproved printhead. The printhead is formed by monolithic integration of MOS transistors switches onto the same silicon substrate containing the resistive elements. In a preferred embodiment, the transistor switches and resistive elements are formed from a single layer of polysilicon with the resistive element formed on a thermally grown field oxide layer having a thickness ranging from about one to four microns. The integrated circuit chips are formed by MOS technology, are thermally stable and can be operated at higher voltages.

Abstract: A thermal ink jet printhead is improved by using heating element structures which space the portion of the heating element structures subjected to the cavitational forces produced by the generation and collapsing of the droplet expelling bubbles from the upstream electrode interconnection to the heating element. In one embodiment this is accomplished by narrowing the resistive area where the momentary vapor bubbles are to be produced so that a lower temperature section is located between the bubble generating region and the electrode connecting point. In another embodiment, the electrode is attached to the bubble generating resistive layer through a doped polysilicon descender. A third embodiment spaces the bubble generating portion of the heating element from the upstream electrode interface, which is most susceptible to cavitational damage, by using a resistive layer having two different resistivities.

Abstract: A thermal ink jet printhead having an ink inlet and a plurality of droplet emitting nozzles is disclosed in which a patterned gasket is provided around each inlet during mass printhead fabrication. A plurality of printheads are obtained by dicing two mated substrates mounted in a holding film frame. A confronting surface of one of the substrates contains a plurality of sets of heating elements and addressing electrodes. The confronting surface of the other substrate contains a plurality of sets of recesses which serve as ink flow directing channels in communication with the nozzles and a reservoir having inlets in the opposite surface of the other substrate. In one embodiment, a polymeric thick film layer is deposited and photo-patterned to provide each inlet with a gasket, the surface of which is coated with a reflowable and curable adhesive for adherence to an ink supply such as an ink cartridge.

Abstract: An improved thermal ink jet printhead and method of fabrication thereof is disclosed of the type formed by the mating and bonding of first and second substrates. The first substrate is silicon with {100} crystal plane surfaces and has anisotropically etched in one surface thereof a linear series of separate through recesses and a plurality of parallel, elongated ink channels grooves. The second substrate has a plurality of heating elements and addressing electrodes patterned on one surface thereof. The through recesses serve as a segmented ink reservoir with each segment having an ink inlet, and the elongated ink channel grooves having one end adjacent the segmented reservoir and the opposite end open to serve as ink droplet emitting nozzles. Each segment of the segmented reservoir is isolated from each other by dividing walls. The dividing walls strengthen the printhead, and the separate through recesses reduce the effects of angular misalignment between mask and first substrate crystal planes.

Abstract: A thermal ink jet printer utilizes a printhead whose electrical connections to the heating elements used to expel the ink droplets has been modified to reduce the effects of parasitic resistance of the common return when a number of resistors are simultaneously addressed. The common return, formed in the same substrate level as the resistor elements, has been modified by forming and interconnecting a second common return. The resistor is connected to an input source by a low resistance connection which is formed to cross-over, or under, the second common.