Patent Description:
The present invention relates to an organic vapor jet print head, having delivery channels and exhaust channels that are orthogonal to one another. Prior art documents relating to the same field are <CIT>, <CIT> and <CIT>.

Opto-electronic devices that make use of organic materials are becoming increasingly desirable for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include organic light emitting diodes/devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light may generally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting. Several OLED materials and configurations are described in U. and <CIT><CIT><CIT> and <CIT>.

One application for phosphorescent emissive molecules is a full color display. Industry standards for such a display call for pixels adapted to emit particular colors, referred to as "saturated" colors. In particular, these standards call for saturated red, green, and blue pixels. Alternatively the OLED can be designed to emit white light. In conventional liquid crystal displays emission from a white backlight is filtered using absorption filters to produce red, green and blue emission. The same technique can also be used with OLEDs. The white OLED can be either a single EML device or a stack structure. Color may be measured using CIE coordinates, which are well known to the art.

As used herein, "solution processible" means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium, either in solution or suspension form.

According to an embodiment, an organic light emitting diode/device (OLED) is also provided. The OLED can include an anode, a cathode, and an organic layer, disposed between the anode and the cathode. According to an embodiment, the organic light emitting device is incorporated into one or more device selected from a consumer product, an electronic component module, and/or a lighting panel.

According to an embodiment, a device may have a first depositor that includes one or more delivery apertures surrounded by one or more exhaust apertures, where the one or more delivery apertures and the one or more exhaust apertures are enclosed within a perimeter of a boss that protrudes from a substrate-facing side of the one or more delivery apertures. The delivery channels for the one or more delivery apertures and exhaust channels for the one or more exhaust apertures may be routed orthogonally to each other. The one or more delivery apertures may be configured to permit jets of delivery gas pass through a lower surface of the first depositor. The lower surface of the first depositor may include the one or more exhaust apertures to remove surplus vapor from a delivery zone.

The one or more exhaust apertures of the device may be a single oval exhaust aperture. The single oval exhaust may be formed using a SOI (silicon-on-insulator) dissolved wafer process disclosed herein. The device may include a second depositor, where each of the first and second depositors is enclosed within its own boss or is arranged on a common boss. The first depositor and the second depositor may be arranged in different ranks, and a printing pitch may be defined by the shortest distance orthogonal to a print direction between centers of the first and second depositors.

The exhaust channels of the device may be in a plane of the one or more delivery apertures, and the delivery channels may be enclosed within pillars normal to the plane of the one or more delivery apertures that extend through the exhaust channel layer. The delivery channels may receive delivery gas to provide to the one or more delivery apertures, and the delivery channel may include a plurality of sub-channels through a lower surface of the first depositor that each feed a different delivery aperture of the one or more delivery apertures. At least one delivery via may be disposed at an opposite end of the delivery channels from the one or more delivery apertures, where the at least one delivery via may receive delivery gas for the first depositor.

The process gas may be drawn through the one or more exhaust apertures and exits through the exhaust channels of the device. The confinement gas may be distributed via a recess disposed adjacent to the boss of the first depositor. The exhaust channels of the device may form continuous cavities that are separated by walls. An arrangement of the exhaust channels may be parallel to a print direction, and/or may have an annular ring arrangement. A shape of the one or more delivery apertures may be circular apertures or slit apertures. Jets from the circular apertures diverge in all directions in a substrate plane when impinged on a substrate or diverge in orthonormal directions, and the jets from the slit apertures diverge in directions orthonormal to a substrate normal and a major axis of a slit of the slit apertures.

The device may include confinement apertures with planes parallel to a substrate plane, where the confinement apertures are positioned on the deposition bosses. The confinement channels of the device may be interdigitated with the exhaust channels. The first depositor and other depositors may be arranged in banks, where each bank deposits a different emissive layer composition to produce a different color of an organic light emitting device. The banks may be offset from each other along a print direction by a subpixel separation for each color.

According to an embodiment, a method of forming a print head may include forming an upper portion of a micronozzle array on a first side of a double side polished (DSP) silicon wafer, covering a first surface of the DSP silicon wafer with a photolithography patterned mask, etching blind holes into the first surface of the DSP silicon wafer using deep reactive ion etching (DRIE) to form delivery vias and delivery channels of the micronozzle array, and etching a second side of the DSP silicon wafer using a nested mask that is patterned with photolithography to form exhaust channels and internal pillars. The silicon wafer may be approximately <NUM> in thickness.

The upstream portions of the delivery channels may be formed so as to be wider than a downstream portions of the delivery channels. The upstream portions and the downstream portions of the delivery channels may be formed using a nested mask and a two-stage etch. A total etch depth of the two-stage etch for the delivery via and the delivery channels may be <NUM>-<NUM>. The etching the second side of the DSP silicon wafer may be performed in two stages, which include etching a lower surface to a depth of <NUM>-<NUM> to define the exhaust channels and the internal pillars of the micronozzle array, where each pillar surrounds a delivery channel and separates it from a surrounding exhaust channel, and etching an opening over a face of the internal pillars to create a through hole for the delivery channels. A lower portion of the micronozzle array may be defined in a silicon-on-insulator (SOI) wafer. The SOI wafer may have a thickness of <NUM>.

The method may include masking a device layer and patterning the device layer with photolithography, etching the device layer through approximately two-thirds of its thickness with DRIE to form an elliptical trench to form part of the exhaust channels, and forming a central rectangular trench to be part of the delivery channels. The method may include joining a handle to a device layer by an oxide layer, where the handle provides mechanical support for the device layer during processing. The method may include bonding the DSP and SOI wafers, where a joint connects the faces of the pillars on the DSP wafer to the ridges of the SOI wafers to form a seal that separates the delivery channels and the exhaust channels into distinct flow paths. The method may include removing the handle layer, patterning a nested etch mask on the underside of the device layer using photolithography, and etching the underside of the wafer. The etching may include etching to define raised regions on the underside of the micronozzle array and the exhaust apertures, and etching to define and open the delivery apertures by removing portions of a silicon membrane covering a central trench leading to the delivery channels. The delivery apertures may be defined by direct photolithography patterning, followed by etching through a shallow membrane.

The method may include connecting exhaust apertures to the exhaust channels through a dogleg structure, where an upper portion of the dogleg is formed by elliptical trench etched on a SOI wafer, and a lower portion of the dogleg is formed by the nested etch on the underside of a SOI device layer. The method may include metallizing an exposed portion of the DSP silicon wafer face after etching, forming a film stack that includes an adhesion layer, a diffusion blocking layer, and a capping layer, and separating the micronozzle arrays by dicing the DSP silicon wafer. The method may include forming a seal between the micronozzle array and a manifold, where the manifold may provide the micronozzle array with delivery gas having organic vapor, and that withdraws a stream of exhaust gasses from the exhaust channels. The method may include forming a joint between the DSP silicon wafer and a face of a carrier plate, where the delivery vias and exhaust vias on the DSP silicon wafer match ports of the carrier plate and forming a joint between the carrier plate and the manifold.

<NPL>; ("Baldo-<NUM>") and <NPL>) ("Baldo-II"). <NUM>-<NUM>.

More examples for each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in <CIT>. An example of a p-doped hole transport layer is m-MTDATA doped with F<NUM>-TCNQ at a molar ratio of <NUM>:<NUM>, as disclosed in <CIT>. Examples of emissive and host materials are disclosed in <CIT>. An example of an n-doped electron transport layer is BPhen doped with Li at a molar ratio of <NUM>:<NUM>, as disclosed in <CIT>. <CIT> and <CIT> disclose examples of cathodes including compound cathodes having a thin layer of metal such as Mg:Ag with an overlying transparent, electrically-conductive, sputter-deposited ITO layer. The theory and use of blocking layers is described in more detail in <CIT> and <CIT>. Examples of injection layers are provided in <CIT>. A description of protective layers may be found in <CIT>.

The simple layered structure illustrated in <FIG> and <FIG> is provided by way of non-limiting example, and it is understood that embodiments of the invention may be used in connection with a wide variety of other structures. The specific materials and structures described are exemplary in nature, and other materials and structures may be used. Functional OLEDs may be achieved by combining the various layers described in different ways, or layers may be omitted entirely, based on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many of the examples provided herein describe various layers as comprising a single material, it is understood that combinations of materials, such as a mixture of host and dopant, or more generally a mixture, may be used. Also, the layers may have various sublayers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device <NUM>, hole transport layer <NUM> transports holes and injects holes into emissive layer <NUM>, and may be described as a hole transport layer or a hole injection layer. In one embodiment, an OLED may be described as having an "organic layer" disposed between a cathode and an anode. This organic layer may comprise a single layer, or may further comprise multiple layers of different organic materials as described, for example, with respect to <FIG> and <FIG>.

Structures and materials not specifically described may also be used, such as OLEDs comprised of polymeric materials (PLEDs) such as disclosed in <CIT>. By way of further example, OLEDs having a single organic layer may be used. OLEDs may be stacked, for example as described in <CIT> The OLED structure may deviate from the simple layered structure illustrated in <FIG> and <FIG>. For example, the substrate may include an angled reflective surface to improve out-coupling, such as a mesa structure as described in <CIT>, and/or a pit structure as described in <CIT>.

Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink-jet, such as described in <CIT> and <CIT> organic vapor phase deposition (OVPD), such as described in <CIT> and deposition by organic vapor jet printing (OVJP), such as described in <CIT>. Other suitable deposition methods include spin coating and other solution based processes. Solution based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding such as described in <CIT> and <CIT> and patterning associated with some of the deposition methods such as ink-jet and OVJD. Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, and preferably containing at least <NUM> carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents having <NUM> carbons or more may be used, and <NUM>-<NUM> carbons is a preferred range. Materials with asymmetric structures may have better solution processibility than those having symmetric structures, because asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the present invention may further optionally comprise a barrier layer. One purpose of the barrier layer is to protect the electrodes and organic layers from damaging exposure to harmful species in the environment including moisture, vapor and/or gases, etc. The barrier layer may be deposited over, under or next to a substrate, an electrode, or over any other parts of a device including an edge. The barrier layer may comprise a single layer, or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may include compositions having a single phase as well as compositions having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may incorporate an inorganic or an organic compound or both. The preferred barrier layer comprises a mixture of a polymeric material and a non-polymeric material as described in <CIT>, PCT Pat. Application Nos. <CIT> and <CIT>. To be considered a "mixture", the aforesaid polymeric and non-polymeric materials comprising the barrier layer should be deposited under the same reaction conditions and/or at the same time. The weight ratio of polymeric to non-polymeric material may be in the range of <NUM>:<NUM> to <NUM>:<NUM>. The polymeric material and the non-polymeric material may be created from the same precursor material. In one example, the mixture of a polymeric material and a non-polymeric material consists essentially of polymeric silicon and inorganic silicon.

Devices fabricated in accordance with embodiments of the invention can be incorporated into a wide variety of electronic component modules (or units) that can be incorporated into a variety of electronic products or intermediate components. Examples of such electronic products or intermediate components include display screens, lighting devices such as discrete light source devices or lighting panels, etc. that can be utilized by the end-user product manufacturers. Such electronic component modules can optionally include the driving electronics and/or power source(s). Devices fabricated in accordance with embodiments of the invention can be incorporated into a wide variety of consumer products that have one or more of the electronic component modules (or units) incorporated therein. A consumer product comprising an OLED that includes the compound of the present disclosure in the organic layer in the OLED is disclosed. Such consumer products would include any kind of products that include one or more light source(s) and/or one or more of some type of visual displays. Some examples of such consumer products include flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads-up displays, fully or partially transparent displays, flexible displays, laser printers, telephones, mobile phones, tablets, phablets, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, camcorders, viewfinders, micro-displays (displays that are less than <NUM> inches diagonal), <NUM>-D displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple displays tiled together, theater or stadium screen, and a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present invention, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range comfortable to humans, such as <NUM> C to <NUM> C, and more preferably at room temperature (<NUM>-<NUM> C), but could be used outside this temperature range, for example, from -<NUM> C to <NUM> C.

In some embodiments, the OLED has one or more characteristics selected from the group consisting of being flexible, being rollable, being foldable, being stretchable, and being curved. In some embodiments, the OLED is transparent or semi-transparent. In some embodiments, the OLED further comprises a layer comprising carbon nanotubes.

In some embodiments, the OLED further comprises a layer comprising a delayed fluorescent emitter. In some embodiments, the OLED comprises a RGB pixel arrangement or white plus color filter pixel arrangement. In some embodiments, the OLED is a mobile device, a hand held device, or a wearable device. In some embodiments, the OLED is a display panel having less than <NUM> inch diagonal or <NUM> square inch area. In some embodiments, the OLED is a display panel having at least <NUM> inch diagonal or <NUM> square inch area. In some embodiments, the OLED is a lighting panel.

In some embodiments of the emissive region, the emissive region further comprises a host.

In some embodiments, the compound can be an emissive dopant. In some embodiments, the compound can produce emissions via phosphorescence, fluorescence, thermally activated delayed fluorescence, i.e., TADF (also referred to as E-type delayed fluorescence), triplet-triplet annihilation, or combinations of these processes.

The OLED disclosed herein can be incorporated into one or more of a consumer product, an electronic component module, and a lighting panel. The organic layer can be an emissive layer and the compound can be an emissive dopant in some embodiments, while the compound can be a non-emissive dopant in other embodiments.

The organic layer can also include a host. In some embodiments, two or more hosts are preferred. In some embodiments, the hosts used maybe a) bipolar, b) electron transporting, c) hole transporting or d) wide band gap materials that play little role in charge transport. In some embodiments, the host can include a metal complex. The host can be an inorganic compound.

The materials described herein as useful for a particular layer in an organic light emitting device may be used in combination with a wide variety of other materials present in the device. For example, emissive dopants disclosed herein may be used in conjunction with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes and other layers that may be present. The materials described or referred to below are non-limiting examples of materials that may be useful in combination with the compounds disclosed herein, and one of skill in the art can readily consult the literature to identify other materials that may be useful in combination.

Various materials may be used for the various emissive and non-emissive layers and arrangements disclosed herein. Examples of suitable materials are disclosed in <CIT>.

A hole injecting/transporting material to be used in the present invention is not particularly limited, and any compound may be used as long as the compound is typically used as a hole injecting/transporting material.

An electron blocking layer (EBL) may be used to reduce the number of electrons and/or excitons that leave the emissive layer. The presence of such a blocking layer in a device may result in substantially higher efficiencies, and or longer lifetime, as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and/or higher triplet energy than the emitter closest to the EBL interface. In some embodiments, the EBL material has a higher LUMO (closer to the vacuum level) and or higher triplet energy than one or more of the hosts closest to the EBL interface. In one aspect, the compound used in EBL contains the same molecule or the same functional groups used as one of the hosts described below.

The light emitting layer of the organic EL device of the present invention preferably contains at least a metal complex as light emitting material, and may contain a host material using the metal complex as a dopant material. Examples of the host material are not particularly limited, and any metal complexes or organic compounds may be used as long as the triplet energy of the host is larger than that of the dopant. Any host material may be used with any dopant so long as the triplet criteria is satisfied.

A hole blocking layer (HBL) may be used to reduce the number of holes and/or excitons that leave the emissive layer. The presence of such a blocking layer in a device may result in substantially higher efficiencies and/or longer lifetime as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and or higher triplet energy than the emitter closest to the HBL interface. In some embodiments, the HBL material has a lower HOMO (further from the vacuum level) and or higher triplet energy than one or more of the hosts closest to the HBL interface.

An electron transport layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped), or doped. Doping may be used to enhance conductivity. Examples of the ETL material are not particularly limited, and any metal complexes or organic compounds may be used as long as they are typically used to transport electrons.

Embodiments of the disclosed subject matter provide architectures for depositors in an OVJP (organic vapor jet printing) tool that utilizes the DEC (delivery, exhaust, confinement) method to control the shape of printed features. Delivery and exhaust apertures may be in the plane of the die rather than on its edge. Many of the limitations of an edge-on micronozzle array may be from a fabrication process that may not define apertures directly by photolithography. An in-plane micronozzle array system may be fabricated by a process in which apertures are defined directly by photolithography to meet submicron shape tolerances. Additionally, an in-plane print head may have channels abutting the delivery and exhaust apertures that may be relatively short to maintain uniform flow resistance.

An in-plane print head may provide a higher linear density of depositors, and may allow for apertures to be fabricated to higher tolerances and in more complex designs. The delivery and exhaust channels may be disposed orthogonally to each other to both supply process gas to and withdraw it from the close-coupled microstructures of each depositor. Embodiments of the disclosed subject matter also provide methods for fabricating arrays of these depositors and packaging them for use.

<FIG> shows a depositor on an in-plane micronozzle array die according to an embodiment of the disclosed subject matter. The in-plane depositor includes an array of delivery apertures <NUM> surrounded by one or more exhaust apertures <NUM>. A single oval exhaust aperture may be used. The single oval exhaust may be formed using a SOI dissolved wafer process disclosed herein. The delivery and exhaust apertures may be enclosed within the perimeter of a boss <NUM> that protrudes from the substrate facing side <NUM> of the micronozzle array.

A plurality of depositors <NUM> may be arranged in an array as shown in <FIG>. Routing of the delivery and exhaust channels to service each depositor <NUM> may have a greater width than the desired pitch of printed features. Depositors <NUM> may be arranged in a plurality of ranks to print at a finer pitch. Although first <NUM>, second <NUM>, and third <NUM> ranks are shown in <FIG>, there may be greater or fewer ranks of depositors. The printing pitch may be defined by the shortest distance <NUM> orthogonal to the print direction between the centers of two depositors <NUM>. Each depositor <NUM> may be on its own boss or a plurality of depositors may be arranged on common bosses <NUM>, as shown in <FIG>.

The delivery and exhaust apertures may both be etched into a thin membrane. This creates the challenge of addressing two sets of apertures distributed over the membrane with two sets of channels behind the membrane. This may be solved by routing the delivery and exhaust channels orthogonally to each other. The exhaust channels may be in the plane of the micronozzle array, while delivery channels may be enclosed within pillars normal to the plane of the micronozzle array that extend through the exhaust channel layer.

<FIG> shows an internal cross section of a depositor on an in-plane micronozzle array die according to an embodiment of the disclosed subject matter. Delivery apertures <NUM> may permit jets of delivery gas to pass through a membrane <NUM> that forms the lower surface of the depositor. An oval exhaust aperture <NUM> may be cut into the membrane <NUM> to remove surplus vapor from a delivery zone. The region of membrane <NUM> between the delivery and exhaust apertures <NUM> may serve a function analogous to the DE spacers in edge-on embodiments of DEC OVJP. The region of membrane <NUM> between the delivery and exhaust apertures <NUM> may provide a confined flow path between a delivery aperture and its closest exhaust aperture that brings the delivery jet into close contact with the substrate <NUM>. A ring <NUM> of the membrane surrounding the exhaust aperture <NUM> may function similarly to the EC spacer described throughout, where the EC spacer may be a distance between an exhaust aperture and a confinement aperture. The ring <NUM> of the membrane may collimate the flow of confinement gas to better block the spreading of delivery gas beyond the exhaust aperture.

Delivery gas may be provided to the delivery aperture <NUM> through a delivery channel <NUM>. Its narrowest portion may include a plurality of sub-channels <NUM> through the membrane <NUM> that each feed a different delivery aperture <NUM>. At the opposite end of the delivery channel <NUM> may be a delivery via <NUM> into which delivery gas for the depositor is fed. The confined geometry at the downstream end of the channel may have small features, while larger features may provide for a low-impedance flow path. The delivery channel <NUM> may begin wide, and may narrow based on the amount of space available. Process gas drawn through the exhaust apertures <NUM> may leave through the exhaust channels <NUM>. Like the delivery channel <NUM>, the exhaust channel <NUM> may be narrow near the apertures <NUM> and wider further from them. The wide portion of the exhaust channel <NUM> connects to exhaust vias (not shown). The wide portion of the exhaust channel <NUM> may connect to the exhaust aperture <NUM> through a dogleg <NUM>. Confinement gas may be distributed between depositors through recesses <NUM> etched into the underside of the micronozzle array between the depositor bosses.

<FIG> shows an exhaust channel layout of from the depositor side of an in-plane micronozzle array die, and <FIG> shows the exhaust channel layout from the via side of an in-plane micronozzle array die according to embodiments of the disclosed subject matter.

That is, <FIG> shows the underside, as seen from the substrate, and <FIG> shows the vias that connect to a delivery gas source and an exhaust sink. Exhaust channels may extend between the front <NUM> and rear <NUM> of the array. Exhaust channels may run behind the depositors and may be sufficiently wide to evenly provide exhaust extraction. Typically, the depositors <NUM> may sit within the in-plane extent of an exhaust channel. The exhaust channels may be separated by solid walls, or they may form a continuous cavity supported by discontinuous walls made form solid pillars. The walls between channels may be represented by dashed lines <NUM>. Exhaust channels may be parallel to the print direction, or they may be angled (as shown in <FIG>) to accommodate multiple ranks of depositors. Exhaust channels may extend between exhaust vias <NUM> located near the front and rear edges <NUM>, <NUM> of the micronozzle array. Withdrawing exhaust from both ends of the channel may improve both exhaust conductance and the uniformity of exhaust service to depositors on a common exhaust channel. Delivery vias <NUM> may correspond to depositors <NUM> on the opposite side. Delivery channels may extend downward from every delivery via and may orthogonally cross the exhaust aperture to connect to the depositor. Delivery vias may be arranged individually or in ranked clusters (as shown in <FIG>), depending on the depositor arrangement.

The arrangement presented in <FIG> may be a preferred embodiment, although alternate configurations may be possible, so long as the exhaust aperture is in a position to capture all of the streamlines of gas flow emitted from the delivery apertures under operational condition. Round apertures may improve material utilization efficiency relative to slit nozzles. The jet from a round aperture may diverge in all directions in the substrate plane when it impinges on the substrate. This may bring a greater fraction of organic vapor laden gas from the jet into contact with the substrate. The jet from a slit nozzle may diverge in directions orthonormal to the substrate normal and the major axis of the slit. Depositors may typically be much longer than they are wide. A long array of delivery apertures may present a narrow section perpendicular to the direction of printing while maximizing the delivery aperture area over printing zones. This optimizes printing speed without increasing feature size.

<FIG> shows an embodiment of an RGB pixel design compatible with OVJP according to an embodiment of the disclosed subject matter. The pixel <NUM> may include three separate electrodes that define the active area of blue <NUM>, green <NUM>, and red <NUM> subpixels. The subpixels may be separated by a margin <NUM> that is masked with an insulating grid material. A thin film feature deposited by OVJP may have uniform thickness within the active area of a subpixel and it may not extend into the active area of a neighboring subpixel. Printed features may be no wider than the subpixel width plus two times the margin width, less positioning tolerances. A typical pixel in an <NUM> display may have feature sizes of less than <NUM> for blue pixels and <NUM> for red and green pixels. The region of controlled thickness uniformity may be the width of the subpixel plus positioning tolerances, and uniformity may be greater than <NUM>% to print a useful subpixel. The uniformity over width w may be defined in eq. <NUM> below. The uniform region may be typically at least <NUM> wide for blue subpixels and <NUM> wide for red and green subpixels.

Two variations of this depositor type are show in <FIG> shows a delivery and exhaust aperture configuration of a depositor to print devices with a <NUM> wide active area according to an embodiment of the disclosed subject matter. The depositor of <FIG> may be configured to print red and green devices. The circular delivery apertures <NUM> may be arranged in rows of four orthogonal to the print direction. As shown in the example of <FIG>, spacing between apertures may equidistant, but the row is shifted slightly to one side. The adjacent rows <NUM> may be a mirror image, shifted to the other side. The lateral dithering of apertures created by mirroring may distribute delivery jets more evenly over the printing zone. The lateral dithering of apertures may also permit apertures to be packed more densely. A single elliptical exhaust aperture <NUM> may surrounds the array of delivery apertures. The delivery and exhaust apertures may sit on a raised boss <NUM>, which may be surrounded by recesses <NUM> to permit the free flow of confinement gas between depositors.

A scale bar <NUM> indicates a width of <NUM>. <FIG> shows a delivery and exhaust aperture configuration of a depositor to print devices with a <NUM> wide active area according to an embodiment of the disclosed subject matter. The wider depositor of <FIG> may be configured to print the blue devices. The delivery apertures may be arranged in wider rows of five <NUM>, but the design is otherwise similar to that shown in <FIG>. A plurality of delivery apertures may be preferable to fewer delivery apertures for uniformity and sidewall sharpness, while wider apertures may improve utilization efficiency. The aperture density may be balanced against the size of individual apertures.

The deposition thickness profiles of features printed by the depositors in <FIG> are plotted in <FIG>, where <FIG> shows a thickness cross section of a line printed by a depositor to print devices with a <NUM> wide active area, and <FIG> shows a thickness cross section of a line printed by a depositor optimized to print devices with a <NUM> wide active area according to embodiments of the disclosed subject matter. The horizontal axis <NUM> shown in <FIG> may give distance from the center of the depositor orthogonal to the direction of printing in microns. The vertical axis <NUM> shown in <FIG> may indicate thickness in arbitrary units.

The plotted curve <NUM> in <FIG> may indicate the cross sectional thickness profile of the feature printed by the depositor in FIG. The outermost vertical lines <NUM> shown in <FIG> indicate a total allowed width of the printed feature. The profile of the feature may not extend beyond lines <NUM>. The feature width may be under specification, with FW5M = <NUM>. The inner vertical lines <NUM> may indicate the <NUM> width over which uniformity may be controlled. This may correspond to the width of the active area of the printed device. The pair of horizontal lines <NUM> may indicate the maximum and minimum thickness for this region. The profile may lie within the rectangle formed by the horizontal lines <NUM> and inner vertical lines <NUM>, indicating that thickness uniformity is within specification. In this case, U<NUM> =<NUM>% when w =<NUM> in equation (<NUM>) above.

The plotted curve <NUM> in <FIG> may indicate the cross sectional thickness profile of the feature printed by the depositor in FIG. This feature may be allowed to be wider that the feature of FIG. The outer vertical lines <NUM> may indicate the maximum allowed feature width of <NUM>. The actual FW5M = <NUM> may be inside of the feature width specification. The inner vertical lines <NUM> may indicate the <NUM> width over which uniformity is controlled. The area bounded by the horizontal lines <NUM> and inner vertical lines <NUM> may represent a window for <NUM>% thickness uniformity. It may enclose the profile, and U<NUM> =<NUM>% when w = <NUM> in equation (<NUM>) above.

An embodiment of an in-plane print head may be fabricated by the following process. Other processes may be possible to produce similar structures and processing of this structure may vary considerably from the process flow presented. <FIG> show operations for etching channels and vias into a double side polished Si wafer used to assemble micronozzle arrays according to embodiments of the disclosed subject matter.

The upper portion of the micronozzle array may be formed from a double side polished (DSP) Si wafer of approximately <NUM> in thickness. Its top surface may be covered with a photolithographically patterned mask. Blind holes may be etched into the wafer face with deep reactive ion etching (DRIE). <FIG> shows the wafer after the top surface of the wafer is etched. The etchings may form the delivery vias <NUM> and delivery channels of the micronozzle array. The upstream portion of the delivery channel may be wider than the downstream portion to reduce the impedance to delivery flow. This may be achieved using a nested mask and a two stage etch. The total etch depth may be <NUM>-<NUM>. A Si membrane <NUM> may be disposed between the floor of the etching and the underside of the wafer.

The opposite side of the wafer may be etched to the configuration shown in <FIG>. A nested mask on the lower surface of the wafer may be patterned with photolithography. The etching may be performed in two stages. The lower surface may be first etched to a depth of <NUM>-<NUM> to define the exhaust channels <NUM> and internal pillars <NUM> of the micronozzle array. Each pillar may surround a delivery channel and may separate it from the surrounding exhaust channel. The pillars may have an elliptical cross section. The second stage of the etch may open the Si membrane over the face of the pillar to create a through hole <NUM> for the delivery channel.

<FIG> show operations for etching a SOI wafer, bonding it to a DSP wafer, and completing the micronozzle arrays according to embodiments of the disclosed subject matter. The lower portion of the micronozzle array may be defined in a SOI wafer with a relatively thick device layer <NUM> of <NUM> as shown in <FIG>. A SOI wafer may permit thin and/or delicate structures to be fabricated in the device layer <NUM> prior to bonding. The device layer <NUM> may be masked and patterned with photolithography. The device layer <NUM> may be etched through approximately two thirds of its thickness with DRIE to form an elliptical trench <NUM> that will become part of the exhaust channel. A central rectangular trench <NUM> produced in the same step may become part of the delivery channel <NUM>. The elliptical and rectangular trenches may be separated by an elliptical ridge <NUM> that corresponds to the pillar on the DSP wafer. This ridge <NUM> may bond to the pillar and seal the delivery and exhaust channels from each other when the two wafers are bonded. A handle layer <NUM> may be joined to the device layer <NUM> by an oxide layer <NUM>. The handle layer <NUM> may provide mechanical support for the device layer <NUM> during processing.

The DSP and SOI wafers may be bonded as shown in <FIG>. The joint <NUM> may connect the faces of the pillars on the DSP wafer bond to the ridges on the SOI wafers. This may form a seal that separates the delivery and exhaust channels into distinct flow paths. Walls between etched exhaust channel trenches on the DSP wafer (not shown) may bond to the face of the SOI wafer. The handle layer <NUM> may be removed to yield the structure in <FIG>. A nested etch mask may be patterned on the underside of the device layer using photolithography. The buried oxide layer may comprise part of the nested mask.

The underside of the wafer may be etched in two steps. The first, deeper etch may be used to define both the raised regions <NUM> on the underside of the micronozzle array and the exhaust apertures <NUM>. The second etch may define and opens the delivery apertures <NUM> by removing portions of the Si membrane covering the central trench <NUM> leading to the delivery channel <NUM>. The delivery apertures <NUM> may be defined by direct photolithographic patterning followed by etching through a shallow membrane. This may permit the delivery apertures <NUM> and distal portions of the delivery channels <NUM> to be fabricated to very tight tolerances and may ensure a uniform array.

The exhaust aperture <NUM> may connect to the exhaust channel through a dogleg structure illustrated in the inset. The dogleg exhaust channel extends through the device layer membrane. The upper portion <NUM> of the dogleg may be formed by the elliptical trench <NUM> etched in the first etch step on the SOI wafer. The lower portion <NUM> of the dogleg may be formed by the nested etch on the underside of the SOI device layer <NUM>. The unmasked regions of the two etches partially overlap in the plane of the wafer. The width <NUM> of this region of overlap is illustrated in the inset of <FIG>. Each etched region overlaps the other for a small portion of its area. The upper and lower trenches may connect to form a channel through the membrane when etched. The height of the overlap <NUM> where the trenches are open to each other may extend from the floor of the elliptical trench <NUM> in the SOI face to the floor <NUM> of the exhaust aperture trench etched into the underside of the device layer. The exhaust aperture width <NUM> may be defined directly by photolithography. The performance of a depositor may be less dependent on the internal dimensions of the dogleg. The dogleg structure may provide a sufficiently wide bonding surface <NUM> on the ridge for the pillar on the DSP wafer in cases where the spacing <NUM> between delivery and exhaust apertures may be very small. Small delivery to exhaust aperture spacing may be used to print fine features.

After etching is complete, the exposed DSP wafer face may be metallized to facilitate soldering to a carrier plate. The film stack <NUM> may include an adhesion layer, a diffusion blocking layer, and a capping layer. Titanium, platinum, and gold may work well in these respective applications. The micronozzle arrays may be separated by dicing the wafer. Each of the resulting dies may include a micronozzle array.

<FIG> shows the attachment of a die containing a micronozzle array to a process gas manifold through a carrier plate according to an embodiment of the disclosed subject matter. The micronozzle array <NUM> may form a gas-tight seal with a manifold <NUM> within the deposition chamber of the OVJP tool. The manifold <NUM> may provide the micronozzle array with a feed of heated delivery gas including organic vapor, and may withdraw a stream of exhaust gasses from the exhaust channels. Process gasses may be transported by runlines <NUM> within the manifold <NUM>. The configuration of the die and manifold system is shown in <FIG>. The die may be attached to a carrier plate <NUM> to facilitate attachment to the manifold. The die and carrier plate <NUM> may be soldered or brazed together in a preferred embodiment. Other die attach methods like anodic bonding or diffusion welding may be used. The attachment operation may form a permanent joint <NUM> between the DSP wafer side of a die and a face of the carrier plate <NUM>. The delivery and exhaust vias <NUM> on the die may match to ports <NUM> on the carrier plate <NUM>. The joint <NUM> may form a gas tight seal around these ports and vias. A second joint <NUM> may seal the carrier plate to the manifold. It may be possible to disassemble the second joint <NUM> for maintenance operations on the print head. The die and carrier plate <NUM> may form a replicable component of the print head, while the manifold <NUM> may be a permanent component. A gasket <NUM>, such as a metal c-ring, may seal the joint between the die and carrier plate <NUM>. The die may not be sealed directly to the manifold <NUM>, since a metal carrier plate <NUM> may provide sufficient pressure on the gaskets <NUM>. The glands <NUM> to seat the gaskets <NUM> may be milled into the manifold <NUM> to simply the carrier plate <NUM>. Pressure for the metal gasket seal between the carrier plate <NUM> and the manifold <NUM> may be provided by bolts <NUM>.

The carrier plate <NUM> may be made of metal. Molybdenum may be preferred for braze and/or solder attachment because it matches the coefficient of thermal expansion (CTE) of Si well from room temperature to the reflow temperature of relatively high melting solders like Au/In alloy. The OVJP tool may operate at temperatures of up to <NUM> or more, so CTE may match over a very wide range of temperatures for a reliable bond. The carrier plate <NUM> may be milled, ground, lapped, and polished to provide a compatible bonding surface with the micronozzle array <NUM> on one side and a metal gasket sealing surface on the other side. The carrier plate <NUM> may be electroplated with additional metal layers and capped with gold to improve wetting of the solder. The micronozzle array <NUM> and carrier plate <NUM> may be aligned and joined at high temperature under pressure. Bonding may be performed in room air or a vacuum, inert, or reducing atmosphere.

<FIG> shows an embodiment of a carrier plate in top (left) and bottom (right) views. A die including a micronozzle array may be bonded to a raised, finished surface <NUM> on the plate. The surface <NUM> may be ported with a slot <NUM> that covers the surface area containing the delivery vias on the die. This may connect the delivery vias on the die to the delivery gas runline <NUM> in the manifold <NUM>. There may be two exhaust ports <NUM>, one on each side of the delivery gas port. Shorter, deeper slots connect the delivery <NUM> and exhaust <NUM> slots to the delivery and exhaust gas ports extending through the carrier plate. The carrier plate <NUM> may be bolted to the manifold through four bolt holes <NUM>. Additional blind holes <NUM> may permit the installation of dowel pins to align the die on the polished surface. The reverse side of the carrier plate <NUM> may provide a finished sealing surface <NUM> for the gaskets <NUM> between the carrier plate <NUM> and the manifold <NUM>. One port <NUM> on the surface may carry the delivery gas to its slot on the front of the carrier plate <NUM>. The other port <NUM> may draw exhaust gas from its corresponding slots.

An embodiment of the in-plane depositor may include confinement apertures with planes parallel to the substrate plane. <FIG> shows depositors in which confinement gas is fed to the deposition zone through confinement apertures according to an embodiment of the disclosed subject matter. Confinement apertures <NUM> may be positioned on the depositor bosses as shown in <FIG>. The confinement apertures <NUM> may be arranged in a line along the long edge of each boss. Confinement apertures <NUM> may be positioned in the recesses <NUM> between bosses in addition to being disposed on the depositor bosses, or instead of being disposed on the depositor bosses. Alternately, the underside of the micronozzle array may be flat if it incorporates sufficient confinement apertures to facilitate uniform confinement flow. Confinement gas may be fed at positive pressure relative to the deposition zone through channels located between the depositors.

<FIG> shows a channel configuration for a micronozzle array in which confinement gas is fed to the deposition zone of each depositor through confinement apertures according to an embodiment of the disclosed subject matter. Confinement channels <NUM> may be interdigitated with the exhaust channels <NUM> as shown in <FIG>. The confinement channels <NUM> and the exhaust channels <NUM> may be separated by vertical sidewalls <NUM> that provide structural support for the die while also sealing the confinement and exhaust channel sets from each other. The confinement channels may be fed from a via on one side of the die <NUM>, while the exhaust channels are connected to a via <NUM> on the other side.

Another embodiment may include multicolor printing from a single die. <FIG> shows a channel configuration for a micronozzle array having three banks of depositors to permit three colors of EML (emissive layer) to be deposited simultaneously according to an embodiment of the disclosed subject matter. Although <FIG> shows the use of confinement apertures, some embodiments may not include confinement apertures. Depositors may be are arranged in three distinct banks, such that each bank deposits a different emissive layer composition to produce a different color of OLED. The first bank <NUM> may deposit material for a blue EML, while the second bank <NUM> may deposit material for a green EML, and the third bank <NUM> may deposit material for a red EML. The banks may be offset from each other along the print direction by the subpixel separation appropriate for each color. The correct delivery gas mixture for each bank of depositors is fed to it through its delivery vias.

The interdigitated arrangement of exhaust and confinement channels may be maintained. The exhaust channels servicing the blue depositors may connect to an exhaust via <NUM> at the top of the array. Confinement and exhaust vias may address two banks of depositors, one on each side, where possible. Confinement gas may be fed to the blue and green depositor banks through a common via <NUM> between the two sets of depositors. Exhaust gasses may be extracted from the red and green depositor banks through a common via <NUM> between those two sets of depositors. Confinement gas for the red depositor bank may be fed from a via <NUM> on the far side of it.

<FIG> shows the dimensional parametrization of the depositors according to an embodiment of the disclosed subject matter. The diameter of the individual delivery apertures may be AD <NUM>. Delivery apertures in an array may have a different shape or size then those shown in <FIG>. DE <NUM> may be the separation between the exhaust aperture and the center of the closest delivery aperture. This aperture may be considered the outer aperture. Delivery apertures may be arranged in rows orthogonal to the print direction. They may be spaced distance DD center to center. The apertures need not be evenly spaced, as shown in <FIG>. The distance between the outer aperture and its neighbor may be DD1 <NUM>, the distance between the next neighbor pair may be DD2 <NUM>, and so on. Rows may be separated by distance ΔY <NUM> along the print direction. Each row may be a mirror image of its neighbors, so that the side on which the outer aperture is distance DE from the nearest exhaust aperture alternates. The total width of the membrane containing the delivery apertures between the inner edges of the exhaust apertures may be TD <NUM>. Finally, the width of the exhaust aperture may be Ewd <NUM>. The total length in the print direction of the delivery aperture array may be <NUM> for both depositors. The separation between the membrane containing the delivery apertures and the substrate is given by fly height g.

The gas ambient surrounding the depositor is argon at <NUM> Torr. The depositor may be heated to <NUM> and the substrate is cooled to <NUM>. Helium delivery gas may be fed to the depositor at <NUM> sccm. A helium/argon exhaust mixture is withdrawn at a rate of <NUM> sccm/depostior. All transport properties are calculated from kinetic theory (see, e.g., <NPL>). The organic vapor is modeled as a dilute component of the gas mixture with a molecular mass of <NUM>/mol and a molecular diameter of <NUM>. Simulations were performed using COMSOL Multiphysics <NUM>. 3a finite element modeling software.

Claim 1:
An organic vapor jet print head device comprising a first and second depositor (<NUM>, <NUM>):
the first depositor (<NUM>, <NUM>) for printing devices with a <NUM> or <NUM> wide active area comprising:
an array of circular or elliptical delivery apertures (<NUM>, <NUM>, <NUM>, <NUM>) arranged in rows of four or five orthogonal to a print direction and surrounded by one or more exhaust apertures (<NUM>, <NUM>, <NUM>, <NUM>),
wherein the spacing between the delivery apertures (<NUM>, <NUM>, <NUM>, <NUM>) is equidistant,
wherein the row is shifted to one side and the adjacent rows are a mirror image, shifted to the other side, wherein the delivery apertures (<NUM>, <NUM>, <NUM>, <NUM>) and the one or more exhaust apertures (<NUM>, <NUM>, <NUM>, <NUM>) are enclosed within a perimeter of a boss (<NUM>, <NUM>, <NUM>) that protrudes from a substrate-facing side (<NUM>) of the delivery apertures (<NUM>, <NUM>, <NUM>, <NUM>),
wherein the one or more delivery apertures (<NUM>, <NUM>, <NUM>, <NUM>) are configured to permit jets of delivery gas pass through a lower surface of the first depositor (<NUM>, <NUM>), and
wherein the lower surface of the first depositor (<NUM>, <NUM>) includes the one or more exhaust apertures (<NUM>, <NUM>, <NUM>, <NUM>) to remove surplus vapor from a delivery zone,
wherein the boss (<NUM>, <NUM>, <NUM>) is surrounded by recesses (<NUM>, <NUM>, <NUM>) to permit free flow of confinement gas between the first depositor (<NUM>, <NUM>) and a second depositor (<NUM>, <NUM>) enclosed within its own boss (<NUM>, <NUM>, <NUM>).