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: A method of fabricating extended arrays of image reading or writing subunits and in particular a pagewidth thermal ink jet printhead from a plurality of discrete thermal ink jet printhead subunits is disclosed. Each thermal ink jet printhead subunit includes a heater plate subunit having a plurality of resistive elements on an upper surface thereof and a channel plate subunit having a plurality of channels corresponding in number and position to the resistive elements on a base surface thereof, the upper surface of the heater plate subunit being attached to the base surface of the channel plate subunit to define a thermal ink jet printhead subunit having a plurality of channels forming nozzles with a resistive element in communication with each channel.

Abstract: Overlapping chip replaceable subunits for RIS or ROS array bars are disclosed. The subunits include a planar semiconductive substrate having at least one component and supporting circuitry on a surface thereof. The semiconductive substrate has first and second side edges, a front edge and a width equal to a distance between the first and second side edges. The planar semiconductive substrate is mounted on a planar support which can be, for example, a daughterboard/heat sink assembly having at least one electrode having a terminal at one end thereof. The planar support also has first and second side edges, a front edge and a width equal to a distance between the first and second side edges. The width of the support is less than the width of the semiconductive substrate so that the first and second side edges of the planar semiconductive substrate extend outwardly beyond the first and second side edges, respectively, of the support.

Abstract: Overlapping chip replaceable subunits for RIS or ROS array bars are disclosed. The subunits include a planar semiconductive substrate having at least one component and supporting circuitry on a surface thereof. The semiconductive substrate has first and second side edges, a front edge and a width equal to a distance between the first and second side edges. The planar semiconductive substrate is mounted on a planar support which can be, for example, a daughterboard/heat sink assembly having at least one electrode having a terminal at one end thereof. The planar support also has first and second side edges, a front edge and a width equal to a distance between the first and second side edges. The width of the support is less than the width of the semiconductive substrate so that the first and second side edges of the planar semiconductive substrate extend outwardly beyond the first and second side edges, respectively, of the support.

Abstract: Modular partial bars include a substrate bar having a length and a plurality of printhead subunits attached to only one side of the substrate bar, each printhead subunit being spaced from an adjacent printhead subunit. These modular partial bars are used as building blocks to form full width staggered array printheads. When the printhead subunits are arranged on each substrate bar so that two substrate bars are capable of forming a full width staggered array printhead, each modular partial bar is referred to as a modular half bar. One modular half bar can be stacked on another modular half bar any number of ways. For example, two half bars can be stacked with their printhead subunit containing sides facing the same direction, away from one another or towards one another.

Abstract: A pagewidth array is fabricated to include a plurality of heating element subunits of the same or differing thicknesses, each subunit having a circuit surface and an opposite base surface. The plurality of subunits is inverted with each of the circuit surfaces facing toward a support surface to expose the base surfaces of each subunit. Each of said subunits is butted against an adjacent subunit to form an end-to-end array of butted subunits, and a conformal adhesive is applied to a bonding substrate which is then applied to the base surfaces of the array of butted substrates to form a coplanar adhesive layer across each of said subunits. The circuit surfaces are protected from damage due to contact with said support surface by applying a stand-off layer of substantially uniform thickness to at least a portion of the circuit surfaces prior to inverting the plurality of subunits. The stand-off layer preferably is polyimide.

Abstract: A method of fabricating channel plates for ink jet printheads from a (100) silicon wafer is disclosed. The location of the nozzle-forming channels are accurately located relative to side edges of each channel plate to permit extended arrays of printheads containing these channel plates to be fabricated without discrepancies between the spacing of end nozzles of adjacent subunits. The present invention achieves this result by forming a first set of base etch openings and a second set of base etch openings on a base surface of a (100) silicon wafer. The first set of base etch openings define the locations of side edges of each channel plate. The second set of base etch openings define the locations and dimensions of a plurality of nozzle-defining channels for each channel plate.

Abstract: Process and apparatus for fabricating an extended scanning or printing array in which plural smaller scanning or printing chips are bonded end-to-end onto the surface of a glass substrate having an opaque thermally and/or electrically conductive coating thereon, with the coating removed at discrete sites to allow a photocurable adhesive placed at the sites to be cured through exposure to UV light from underneath the substrate, the photocurable adhesive holding the chips in place while a chip bonding adhesive deposited on the conductive coating where the chips are located is cured to provide a permanent structure.

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: A thermal ink jet printer is disclosed having a printhead with a passageway therein for the circulation of a cooling fluid therethrough. The passageway is parallel and closely adjacent the array of bubble generating heating elements. When the printhead is composed of mated silicon channel and heater plates, the passageway is formed in one embodiment by forming a groove in the heater plate surface opposite the one containing the heating elements and addressing electrodes followed by the mating of a silicon sealing plate having inlet and outlet openings etched therein. Tubes for circulating a cooling fluid, such as ink, are sealingly attached to the inlet and outlet openings. In an alternative embodiment, the groove may be formed in the sealing plate or in both the sealing plate and the printhead heater plate. In another embodiment, the passageway for the cooling fluid is provided by etching a channel in a thick film layer deposited on the heater plate surface opposite the one with the heating elements.

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 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.

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: The vacuum hold down alignment substrate is formed as an array of precisely aligned alignment substrate subunits. Each subunit is formed with an alignment pattern formed in a photo-patternable or electroformable material. When the plurality of alignment substrate subunits are formed into an array to produce the alignment substrate, the alignment patterns are aligned to receive corresponding patterns in discrete subunit devices which are aligned into an array on the alignment 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: 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: An improved method of fabricating a thermal ink jet printhead of the type produced by the mating of an anisotropically etched silicon substrate containing ink flow directing recesses with a substrate having heating elements and addressing electrodes is disclosed. An etch resistant material on one surface of a (100) silicon substrate is patterned to form at least two sets of vias therein having predetermined sizes, shapes, and predetermined spacing therebetween. The predetermined spacing permits selected complete undercutting by an anisotropic etchant within a predetermined etching time period.

Abstract: Relatively small fluid handling devices having a filter bonded on the surface containing the fluid inlets. An example of such a device is a thermal ink jet printhead. A substantially flat filter is placed at the ink inlet to the printhead by a fabrication process which laminates a wafer sized filter to the aligned and bonded wafers containing a plurality of printheads. The individual printheads are obtained by a sectioning operation, which cuts through the two or more bonded wafers and the filter. The filter may be a woven mesh screen or, preferably, an electroformed screen with a predetermined pore size. Since the filter covers one entire side of the printhead, the relatively large contact area prevents delamination and enables convenient leak-free sealing. The filter prevents the entrance of contaminants into the relatively large inlets of the printhead at an early stage of assembly and packaging.

Abstract: A cost effective method of fabricating a large array or pagewidth silicon device having high resolution is disclosed. The pagewidth device is assembled by abutting silicon device sub-units such as image sensors or thermal ink jet printheads. For printheads, the sub-units are fully operational small printheads comprising an ink flow directing channel plate and a heating element plate which are bonded together. A plurality of individual printhead sub-units are obtained by dicing aligned and bonded channel wafers and heating element wafers. The abutting edges of the printhead sub-units are diced in such a manner that the resulting kerfs have vertical to inwardly directed sides which enable high tolerance linear abutment of adjacent sub-units. Alternatively, the wafer surface containing the heating elements is first anisotropically etched to form small V-grooves, one wall of which protects against microcracking during the dicing operation. The other wall of the V-groove is obliterated by the slanted dicing blade.