Patent Description:
The present invention relates to devices and techniques for fabricating devices using OVJP techniques, and devices fabricated using the same.

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 <CIT>, <CIT>, and <CIT>.

For example, <CIT> describes a system including a nozzle, a source of material to be deposited on a substrate in fluid communication with the nozzle, a delivery gas source in fluid communication with the source of material to be deposited with the nozzle, an exhaust channel disposed adjacent to the nozzle, a confinement gas source in fluid communication with the nozzle and the exhaust channel, and disposed adjacent to the exhaust channel.

<CIT> describes a print head comprising a nozzle block comprising a delivery aperture, the delivery aperture being in fluid communication with a source of organic material to be deposited on a substrate by the printing deposition system; one or more shield gas distribution channels, each shield gas distribution channel being disposed above or below the delivery aperture when viewed from below the nozzle block: and one or more exhaust channels disposed adjacent to the delivery aperture such that, during operation of the print head, non-condensing gas flow generated by the delivery aperture is captured by an exhaust aperture.

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. 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.

In an example, not covered by the claims but useful for understanding, 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, an OVJP depositor is provided that includes a delivery aperture in fluid communication with a source of organic material to be deposited on a substrate and a carrier gas, a first exhaust aperture disposed ahead of the delivery aperture, a second exhaust aperture disposed behind the delivery aperture, a first confinement gas aperture disposed laterally adjacent to the delivery aperture, and a second confinement gas aperture disposed laterally adjacent to the delivery aperture and opposite the first confinement gas aperture relative to the first confinement gas aperture. Thereby, the delivery aperture and the first and second exhaust aperture are aligned such that there is a straight line that overlaps at least a portion of each of the delivery aperture and the first and second exhaust aperture. Optionally, the delivery aperture, the first and second exhaust apertures, and the first and second confinement gas apertures may be arranged on a surface of the depositor such that, when the depositor is operated to deposit organic material on a substrate, a first flow of material from the delivery aperture to at least one of the first and second exhaust apertures is parallel to a second flow of material from at least one of the first and second confinement gas apertures. A dimension of the delivery aperture parallel to the direction of relative motion of the depositor and a substrate when the depositor is operated to deposit material on the substrate may be shorter than a distance between an edge of the delivery aperture closest to the second exhaust aperture and an edge of the second exhaust aperture farthest from the delivery aperture. The first exhaust aperture may have a width that is less than a width of the feature that is to be printed on the substrate when the depositor is operated to deposit material on the substrate. For example, the first exhaust aperture may have a width of not more than <NUM>. The exhaust apertures and/or the confinement gas apertures may be oval, circular, rectangular. The delivery aperture and/or the confinement gas apertures may have straight side walls or chamfered side walls. The depositor may have various relative geometries between the various apertures. For example, the delivery-to-exhaust spacing DE of the depositor may be not more than <NUM>. As another example, the delivery-to-confinement spacing DC of the depositor may be not more than <NUM>. The width of the first and second exhaust apertures may be greater than the width of the delivery aperture. Each of the first and second exhaust apertures may have a maximum width of not more than <NUM>. More specifically, each of the first and second exhaust apertures has a maximum width in the range of <NUM>-<NUM>.

In an embodiment, an OVJP nozzle block is provided that includes a plurality of OVJP depositors as disclosed herein. Each depositor may include separate delivery, exhaust, and confinement apertures. Alternatively or in addition, some apertures may be shared between and across multiple depositor configurations, such as where exhaust apertures are shared by multiple delivery apertures.

Embodiments of operating the depositors disclosed herein are also provided. For example, an embodiment of operating an OVJP depositor as disclosed herein includes providing a delivery gas containing an organic material to be deposited on a substrate from a delivery aperture in an OVJP depositor, providing confinement gas to a region between the OVJP depositor and the substrate via a first confinement gas aperture disposed laterally adjacent to the delivery aperture and a second confinement gas aperture disposed laterally adjacent to the delivery aperture and opposite the first confinement gas aperture relative to the first confinement gas aperture, and removing material from the region between the OVJP depositor and the substrate via a first exhaust aperture disposed ahead of the delivery aperture and a second exhaust aperture disposed behind the delivery aperture, wherein the delivery aperture (<NUM>) and the first and second exhaust aperture (<NUM>) are aligned such that there is a straight line that overlaps at least a portion of each of the delivery aperture (<NUM>) and the first and second exhaust aperture (<NUM>). When a depositor is operated to deposit material on a substrate, the molar flow of inert gas through the first and second exhaust apertures in total may be greater than the molar flow of inert gas through the delivery aperture.

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.

As previously disclosed, organic vapor jet printing (OVJP) is one type of technique to deposit layers of an OLED. OVJP techniques use a carrier gas to transport organic material from a heated source container to the print nozzle assembly which is in close proximity to a substrate. OVJP techniques typically are capable of depositing emissive materials in arrays of well-defined lines, which can be interlaced on a substrate surface to create a multicolor OLED display. The design of the print nozzle assembly and the deposition conditions determine characteristics of the printed line. Early OVJP print nozzles typically were capable of producing printed lines with a line width on the order of <NUM>. However, the lines had unacceptable overspray and printing could not be started and stopped rapidly. Recent OVJP techniques, such as Deposition-Exhaust-Confinement (DEC) techniques, may use a combination of delivery apertures in conjunction with exhaust apertures and a gas confinement flow to confine the line width and overspray. DEC depositors may have apertures with a wide variety of shapes, for example to produce features of specific sizes and feature profiles. Examples of specific DEC designs and techniques are described in further detail in <CIT>, <CIT>, and Int'l.

Gas confinement techniques depart from previous OVJP concepts in that they typically use a chamber pressure in the range of <NUM> to <NUM> Torr, rather than a high vacuum environment. Overspray may be eliminated by using a flow of confinement gas to prevent the diffusion and transport of organic material away from the desired deposition region. An example of a DEC depositor design is shown from the perspective of a substrate in <FIG>. The depositor includes a planar surface <NUM> that includes one or more rectangular delivery apertures <NUM>. The delivery apertures may be disposed adjacent to, or in some embodiments between or surrounded by, exhaust apertures <NUM>. In the example arrangement of <FIG> the delivery apertures <NUM> are disposed between pairs of exhaust apertures <NUM>, though other arrangements may be used. During operation of the depositor, a flow of material through the delivery apertures <NUM> contains organic vapor entrained in an inert delivery gas. The exhaust apertures <NUM> withdraw gas from the region under the depositor at a mass flow rate higher than the delivery flow rate. That is, the mass flow rate of material through the exhaust aperture(s) is higher than the mass flow rate of material through the delivery apertures. Accordingly, the exhausts remove the delivery flow, surplus organic vapor entrained within the delivery flow, and a balance of confinement gas that may be drawn from the ambient surrounding the depositor. The delivery and exhaust apertures <NUM>, <NUM> may be separated by a delivery-exhaust ("DE") spacer <NUM>. In this example, the apertures are arranged such that the long axes are parallel to the direction of printing <NUM>, though other arrangements may be used.

In DEC arrangements, the depositors typically are arranged linearly on a micronozzle array <NUM>, so that each depositor borders another on at least one side boundary <NUM>. The top and bottom edges <NUM>, <NUM> of the depositor may be defined by the edges of the micronozzle array. Distribution trenches <NUM> etched into the lower face of the depositor may provide a low impedance path for confinement gas so that the confinement gas flow is evenly distributed across the side boundaries of each depositor. Alternately or in addition, confinement gas may flow in from the edges of the depositor, particularly if these channels are omitted. Arrays may be designed to minimize crosstalk between depositors so that multiple printed features are as close to identical as possible across the width of the depositor array. Additional exhaust apertures may be placed at the ends of the array, for example, to minimize edge effects. The flow field under a micronozzle array therefore has periodic symmetry.

The average thickness t of a printed film is given by t = ηjτ/ρ, where j is the mass flux of organic vapor onto the substrate, τ is the period of time a given point on the substrate is under the aperture, and ρ is the density of the condensed organic material. The utilization efficiency, η, is the fraction of organic vapor issuing from the depositor that condenses on the substrate. Because τ = l/v, where l is the length of the aperture in the direction of relative movement of the depositor and the substrate and v is the relative velocity between the print head and the substrate, a longer delivery aperture permits a given point on the substrate surface to remain under the aperture for a longer time at a given print speed, thereby allowing for faster printing. Accordingly, the apertures of a DEC depositor often may be made as long as manufacturing techniques will permit.

An example of a DEC depositor is shown in cross-section at a line normal to the direction of printing in <FIG>. The width of the delivery aperture <NUM> is D. The mass flow rate of delivery gas through the delivery aperture is given by QD. The DE spacers between the delivery and exhaust have width DE <NUM> and the exhausts have width E <NUM>. The mass flow rate of gas through the exhaust apertures of a depositor is QE. The depositor and substrate are separated by a fly height gap g <NUM>. Confinement gas is fed into the depositor from the edges of the depositor <NUM> at rate QC. The flow of confinement gas opposes the outward spread of organic vapor and directs surplus organic vapor away from the deposition zone through the exhaust apertures as previously disclosed.

In many cases, the material utilization efficiency of a DEC depositor may be relatively poor when printing high resolution features. The DE spacer <NUM> may direct an organic vapor rich flow from the delivery aperture <NUM> into contact with the substrate <NUM> before it is captured by the exhaust aperture <NUM>. <FIG> shows a configuration in which the DE spacer is shorter, such that the streamlines of delivery flow near the substrate <NUM> are sparse, indicating stagnation. Most of the delivery flow <NUM> travels directly to the exhaust aperture without coming into significant contact with the substrate. In contrast, for a depositor with a wider DE spacer as shown in <FIG>, streamlines of flow are shifted closer to the substrate <NUM>. Accordingly, a higher portion of the organic vapor is brought into contact with the substrate.

Larger values of the DE dimension may allow organic vapor to be efficiently utilized, but they print wider features. This is because organic vapor is deposited on the region of substrate located between the stagnation planes <NUM> of the flow field, where the velocity in the horizontal direction is zero. Organic vapor from the delivery aperture spreads outward to the stagnation plane, but no farther, because the confinement <NUM> flow limits further spread and guides surplus organic vapor into the exhaust aperture. The width between the stagnation planes increases linearly with DE, so narrower DE spacers may be required to print smaller features with a DEC depositor. A tradeoff therefore exists between η and feature size. In some configurations, η may be <NUM>% or lower to achieve display-sized features.

In embodiments disclosed herein, a DE spacer as previously described may be aligned with the direction of printing to partially mitigate the expected tradeoff between efficiency and feature size. An example of such a configuration is illustrated in <FIG>. In this arrangement, delivery gas is ejected through a central delivery aperture <NUM> as previously disclosed, and consistent with other DEC type arrangements. The delivery aperture may be surrounded by a pair of exhaust apertures <NUM>, for example so that all three apertures lay in a line that is parallel or essentially parallel to the direction of printing <NUM>. As used herein, features of a depositor may be described as being arranged "ahead of" or "behind" other features, referring to the placement of the features relative to one another with reference to the direction of printing. For example, the exhaust apertures <NUM> are disposed ahead of and behind the delivery aperture <NUM> in <FIG>. Similarly, one exhaust aperture is disposed ahead of or behind the other. Typically a PDC depositor as disclosed herein may be operated by moving the depositor across a substrate along a single axis; however, the relative motion of the depositor and the substrate may be in either direction along the single axis. Accordingly, a feature that is "ahead of" another feature when the device is operating in a forward direction along the axis will be "behind" the feature when the device is operated in a rearward direction along the axis. More generally, two features may be described as being "aligned" along the direction of relative motion if a straight line parallel to the direction of relative motion exists that overlaps at least a portion of each of the two features. For example, the delivery and exhaust apertures <NUM>, <NUM>, respectively in <FIG> are aligned such that there is a straight line that overlaps at least a portion of each aperture. As a specific example, the delivery and exhaust apertures may be aligned such that the centers of the apertures lie in a straight line. As another example, the apertures may be aligned such that the center of each aperture lies within a threshold distance of a straight line that overlaps all the apertures, such as within <NUM>% of the maximum width of the aperture. It may be preferred for the apertures to be centered along a common axis that is parallel to the direction of printing.

Two or more confinement gas apertures <NUM> may be located to either lateral side of the delivery aperture relative to the direction of printing <NUM>. As used herein, depositor features may be described as being "laterally adjacent" to one another if there exists a straight line perpendicular to the relative motion of the depositor and the substrate when the depositor is operated to deposit material on the substrate, such that each of the two "laterally adjacent" features at least partially overlaps the straight line.

A similar, but different arrangement is described in <CIT>. Although the individual operation of the delivery, confinement, and exhaust apertures is similar in the '<NUM> publication and this disclosure, the specific arrangement and resulting gas flows may be significantly different. For example, the '<NUM> publication generally describes configurations in which exhaust apertures are arranged between the delivery apertures and confinement gas sources. That is, DEC-type depositors generally use configurations in which the exhaust apertures would be located at the location of the confinement gas apertures <NUM> in <FIG>, and confinement apertures located outside of the exhaust apertures (i.e., toward the closest outer edge of the depositor nozzle block relative to the exhaust aperture). PDC depositors as disclosed herein arrange the confinement apertures <NUM> and exhaust apertures <NUM> as shown.

In further contrast to such DEC depositors, embodiments disclosed herein provide delivery and confinement flows that are both non-zero and parallel to each other across the boundary between the two. These parallel delivery and confinement (PDC) depositors may be contrasted to the arrangements and operation of DEC configuration depositors in which the in-plane motion of the delivery and confinement flows were in opposition to each other at their interface rather than parallel As disclosed in further detail herein, PDC configurations may offer advantages in material utilization efficiency and relaxed fly height tolerances, while preserving acceptable printing resolution and feature thickness uniformity.

A PDC depositor as disclosed herein may be adequately described and defined by three general geometric properties. The first is that collinear segments passing through the center of the depositor <NUM> should exist such that a first segment <NUM> begins and terminates on the outer edge of a delivery aperture, and the second segment <NUM> begins and terminates on the outer edge of an exhaust aperture. In addition, it may be preferred that the second segment <NUM> is longer than the first segment <NUM>. The extent of a depositor's exhaust aperture system generally is greater than that of the delivery aperture system. It is desirable that every section of delivery aperture <NUM> is separated from the nearest section of confinement aperture <NUM> by a solid section of the depositor surface.

The second geometric property of a PDC depositor as disclosed herein is that the maximum width of the exhaust aperture system <NUM>, from outside edge to outside edge, is less than the intended size of the printed features. For example, to print a <NUM> square feature, the width of the exhaust aperture <NUM> should not be more than <NUM>. As used herein in reference to these geometries, a "width" refers to the distance of a feature in a direction that is orthogonal both to the direction of printing and to the substrate normal. In the view shown in <FIG>, the direction of printing <NUM> is toward the top or bottom of the page, and the substrate normal is in a direction orthogonal to the direction of printing and out of the page. Accordingly, the "width" of the exhaust aperture <NUM> refers to the distance across the page from left to right.

The third geometric property of a PDC depositor as disclosed herein is that the maximum width of the delivery aperture system <NUM> also is less than the intended size of the printed features. The "width" of the delivery aperture system <NUM> as used herein again has the meaning as described above with respect to the exhaust apertures <NUM>.

Embodiments of PDC depositors disclosed herein may exhibit confinement that is less sharp than with DEC type depositors. However, the delivery flow may follow a longer path between the delivery aperture from which it originates and the exhaust aperture that removes unused material and carrier gas from the region between the depositor and the substrate. This means that the organic material in the delivery flow has more time during which it can deposit on the substrate, leading to more efficient utilization of organic material.

<FIG> shows an example of the patterns of flow that may be generated by a depositor as described with respect to <FIG>. The horizontal axis <NUM> gives displacement in the x direction (i.e., orthogonal to the direction of printing and parallel to the substrate) in microns and the vertical axis <NUM> gives displacement in the y direction (i.e., parallel to the direction of printing) in microns with respect to the center of the delivery aperture <NUM>. The delivery flow <NUM> passes from the delivery aperture to the exhaust apertures <NUM>.

As previously disclosed, the delivery flow <NUM> may be surrounded by a confinement flow <NUM> that passes from the confinement apertures <NUM> to the exhaust apertures <NUM>. Notably, the majority of organic material entrained in the carrier gas remains with the streamlines of the delivery flow <NUM>, confining it to a pocket <NUM> that is bounded by the intersection of the delivery and confinement flows <NUM>, <NUM>. The velocity distribution at this intersection is constant and non-zero. Therefore, the delivery and confinement flows <NUM>, <NUM> flow parallel to each other at the flow interface. This may be contrasted with the flows in a DEC depositor as previously disclosed and as described, for example, in <CIT>, in which the flows are anti-parallel.

A secondary stream of confinement flow <NUM> may enter or be provided from the depositor edges. The confinement flow <NUM> may be actively provided, such as via a source of confinement gas similar to that provided with the confinement flow <NUM>, or it may result from conditions in the chamber ambient without a separate generation or delivery mechanism for the flow <NUM>. The confinement flow <NUM> may create a generally arc-shaped region <NUM> around at least a portion of the exhaust aperture <NUM> that prevents delivery flow <NUM> from being pulled to the far side of the aperture <NUM> and thereby widening the deposition zone. That is, the additional confinement flow <NUM> displaces organic vapor so that it only enters the exhaust aperture on a side facing the delivery aperture and prevents the convective action of the exhaust from broadening the organic vapor plume. This may prevents undesirable overspray or enlarged and/or less-well-defined features.

<FIG> shows a schematic of the same flow pattern as in <FIG>, along a cross section taken parallel to the direction of printing. As previously disclosed, the delivery flow <NUM> (in <FIG>) is brought into contact with the substrate <NUM> across the length of the DE spacer <NUM>, which is parallel to the direction of printing. The additional confinement flow fed from the edge of the depositor creates a stagnation plane <NUM> that bounds the spread of delivery flow along the direction of printing as previously disclosed. This is analogous to DEC-type arrangements such as disclosed in <CIT>, in which confinement flow prevents spread perpendicular to the direction of printing.

Examples of cross-sectional thickness profiles for features printed with a PDC depositor as illustrated in <FIG> and <FIG> are shown in <FIG>. The horizontal axis <NUM> shows the relative displacement from the depositor centerline in the x direction (i.e., across the substrate perpendicular to the relative motion of the depositor and the substrate). The vertical axis shows the local flux of organic vapor j at that position in arbitrary units. The shape of the curve is therefore equivalent to the thickness profile of a feature printed with the depositor. The four clusters of lines represent features grown with depositors with DE spacing of <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), and <NUM> (<NUM>). It can be seen from these results that, for a PDC depositor in this configuration, a primary determinant of both the maximum feature thickness and the feature size is DE. As used in this example, the "feature size" refers to the full width of the profile at <NUM>% of its maximum value (FW5M), an example of which is marked for the DE = <NUM> case as <NUM>. Streamlines, printed feature thickness profiles, efficiency estimates and other performance data presented for PDC depositors as disclosed herein were obtained by simulation of the various embodiments disclosed herein using computational fluid dynamics software.

As previously disclosed, the diffusion of organic material from a delivery flow to the relatively stagnant layers of gas immediately above the substrate allows for deposition of the organic material on the substrate. However, diffusion of the organic material between the delivery and confinement flows generally results in a broadening of features printed by the depositor. The time available for both processes increases with greater spacing between the deposition and exhaust apertures. That is, a higher DE spacing generally leads to both an increase in the amount of material deposited and/or efficiency in the deposition of organic material, as well as the undesirable broadening of printed features. As with DEC depositors, a tradeoff exists between η and the printed feature size. However, as indicated by the results shown in <FIG>, it may be less severe for PDC geometries as disclosed herein when compared to DEC depositors and other OVJP depositor arrangements.

Still referring to <FIG>, the individual profiles in each cluster <NUM>, <NUM>, <NUM>, <NUM> reflect profiles generated by PDC depositors with different delivery-to-confinement (DC) spacing. Profiles for DC spacings of <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), and <NUM> (<NUM>) DC spacings are shown. As <FIG> indicates, PDC depositors with larger DC spacing will tend to print features with more uniform deposition profiles that are less sharply peaked in the center. For example, the profile for a DC spacing of <NUM> at <NUM> has a profile with a broader center peak and more uniform width than the profile for the <NUM> DC spacing <NUM>.

For DE spacing of less than about <NUM>, the FW5M is seen to increase slightly with increasing DC. However, for DE spacings of about <NUM> or greater, the FW5M is seen to decrease slightly with increasing DC. A larger DC spacing will require the confinement gas to flow further inward along the x axis before reaching an exhaust aperture, thereby reducing the outward spread of organic vapor in the delivery flow. The feature profiles for a DE spacing of <NUM> at <NUM> intersect with each other at <NUM> because the larger DC spacing produces a feature with a broader center and narrower outer edge tails, while a smaller DC spacing produces a profile with a narrower center and broader tails. A wider DC spacing also improves η for relatively small values of DE because the wider spacing initially causes the organic vapor to spread over a wider region over the substrate, but the effect becomes less significant with increasing DE spacings.

<FIG> shows deposition rate data for example depositors as shown in <FIG>, which plots the normalized total deposition rate J (<NUM>) as a function of DE spacing of the depositor in microns at <NUM>. The total organic flux J shown at <NUM> is j as previously disclosed, integrated across the width of the deposited feature. It can be seen that larger DE spacings result in higher total deposition rates for each flow rate (<NUM>, <NUM>, and <NUM> sccm).

<FIG> shows material utilization efficiency η <NUM> for the same depositor configurations as a function of depositor DE spacing <NUM>. It can be seen that a larger DE spacing increases the time available for organic vapor to diffuse out of the delivery flow and adhere to the substrate, thereby causing an increase of both J and η as previously disclosed. Notably, J is almost independent of QD for DE spacing of under about <NUM>. In such configurations, the DE spacing is not sufficient for a diffusive boundary layer to develop over the substrate. It also can be seen that the difference in deposition rates between depositors having a mass flow rate through the delivery aperture (QD) of <NUM> sccm (<NUM>) and <NUM> sccm (<NUM>) increases notably for DE over about <NUM>. However, the difference in J between mass flow rates of <NUM> sccm (<NUM>) and <NUM> sccm (<NUM>) remains relatively insignificant over the observed rage of DE.

These results can be explained, in part, because the additional material ejected from the delivery aperture at higher QD values may not permeate to the substrate before it is extracted through an exhaust aperture. Material utilization therefore becomes less efficient, and η and QD may have a nearly reciprocal relationship for DE spacings of about <NUM> or less. The relationship between η and QD becomes less sensitive at higher DE values, but in general η still decreases as QD increases.

Feature size trends for the features shown in <FIG> using a depositor configuration as shown in <FIG> are illustrated in <FIG>, which shows the FW5M (full width to <NUM>% of profile maximum) of the printed feature in microns as a function of the DE spacing of the depositor. As this plot illustrates, it has been found that the length of the depositor DE spacing has the most apparent effect on feature size, with feature size increasing linearly or almost linearly with DE size.

The next most significant effect on feature size depends on the value of the DC spacing of the depositor. Feature sizes of features printed by a depositor are shown for DC spacings of <NUM> (filled dots <NUM> connected by a solid line <NUM>), <NUM> (open dots <NUM> connected by a dashed line <NUM>), <NUM> (Xs <NUM> connected by a dotted line <NUM>), and <NUM> (filled triangles <NUM> connected by a dot-dash line <NUM>). As previously noted, it is found that increasing the DC distance increases the FW5M of the resulting features when the DE distance is less than about <NUM>, and decreases the feature FW5M otherwise. As a specific example, the FW5M of a feature printed by a PDC depositor as shown in <FIG> with DE of <NUM> reduces from <NUM> to <NUM> as the DC separation increases from <NUM> to <NUM>.

Similarly, <FIG> shows the printed feature width in microns as a function of the DC distance of the depositor in microns for DE distances of <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), and <NUM> (<NUM>) at a QD flow rate of <NUM> sccm. As shown, it has been found that the feature size increases with DC at relatively short DE lengths because the larger DC distance increases the width of the initial deposition zone under the delivery aperture. Conversely, the printed feature width decreases at higher DC distances when the DE distance is larger. This is because the inward convection of carrier gas from the more widely-spaced confinement apertures towards a centrally-positioned exhaust counteracts the outward diffusion of organic vapor in the delivery flow.

The total deposition mass flow rate QD has a relatively small or negligible effect on the printed feature size, presuming that the values of QE and QD for the depositor are scaled proportionately. The three separate points plotted for each set of DE and DC conditions in <FIG> represent FW5M values for QD =<NUM>, <NUM>, and <NUM> sccm. For all other examples discussed with reference to <FIG>, QE/QD =<NUM> and QC/QD =<NUM>. It has been found that the printed feature sizes cluster together despite the different gas flow rates.

The result that feature size is independent of flow rate is unexpected. Such a result is counterintuitive because diffusion between adjacent flows of delivery gas and confinement gas generally causes broadening of the printed features. The expected broadening therefore depends on the total time that the organic vapor remains below the depositor, and therefore on the gas velocity. This apparent contradiction can be explained by noting that only organic vapor from the closest fluid laminae are able to reach the substrate at high delivery flow rates. The velocity of these laminae is much slower than that of the bulk. The motion of delivery gas near the substrate is largely unaffected by the overall flow rate, and therefore so is the feature size.

The length of the DE spacer defines the characteristic length of the of the flow field underneath a DEC depositor. A delivery jet therefore generally is unable to cross a fly height gap g between the substrate and the lower surface of the depositor of more than about <NUM>-<NUM> times the DE distance to deposit organic vapor onto the substrate. The performance of a DEC depositor therefore may decrease significantly at greater fly heights. In contrast, a larger DE spacing in a PDC depositor configuration as disclosed herein allows the PDC depositor to be operated at greater fly heights, thereby reducing the risk of collision between the depositor and substrate under production conditions.

<FIG> shows a plot of the material utilization efficiency η as a function of the fly height g for a DEC depositor and for a PDC depositor as disclosed herein. The material utilization efficiency decreases with increasing fly height for both depositor designs. However, it has been found that the PDC depositor design may have three times the efficiency of a comparable DEC depositor over the studied range of fly heights. The efficiency curve for the PDC depositor is shown as a solid line <NUM> and the curve for the DEC depositor is shown as a dashed line <NUM>. A PDC depositor can be operated with η =<NUM> at g =<NUM>, while a comparable DEC depositor typically would have to be held within g =<NUM> to achieve comparable performance.

<FIG> shows plots of the FW5M expected from features printed with a PDC depositor <NUM> as disclosed herein, in comparison to a DEC depositor <NUM>. It can be seen that the feature size is more stable across a range of fly heights for the PDC depositor than the DEC depositor. For example, if the maximum permissible feature size is <NUM>, a PDC depositor may be operated at a fly height g of <NUM>, while a comparable DEC depositor may require a fly height of <NUM> or less. As shown by <FIG>, a PDC depositor as disclosed herein expands the range of fly height over which the depositor is able to meet required material utilization efficiencies or feature specifications.

Circular apertures with straight sidewalls, as illustrated in <FIG> and <FIG>, may generate eddies that can create unwanted mixing between the delivery and confinement flows at higher QD values. Some embodiments of PDC depositors as disclosed herein prevent or suppress such eddies by using chamfered sidewalls surrounding the aperture. Examples of flow fields generated by non-chamfered sideweall PDC depositors and chamfered depositors are shown in <FIG>, respectively. In <FIG>, delivery flow is injected to the depositor cross section through straight-walled delivery apertures <NUM> and confinement apertures <NUM>. <FIG> shows a similar configuration in which the delivery and confinement apertures have chamfered sidewalls <NUM>. It has been found that the straight apertures may produce a recirculation cell <NUM> between the delivery and confinement apertures <NUM>, <NUM>, and even stronger recirculation cells <NUM> on the outside of the confinement apertures <NUM>. The recirculation cell between the delivery and confinement apertures disappears for chamfered sidewalls, and the outside recirculation cells are greatly minimized.

The lack of these recirculation zones in the chamfered arrangement significantly reduces or eliminates convective mixing between the delivery and confinement flows. This can be seen from the organic flux contours plotted in <FIG> for the straight and chamfered sidewalls cases, respectively. The straight sidewall arrangement in <FIG> exhibits a zone of high organic flux <NUM> near the center, with long lobes of deposition <NUM> extending outward along the direction of printing. Additional lobes of deposition <NUM> extend laterally outward from the center orthogonal to the direction of printing. These regions of deposition broaden the printed feature, but they may be reduced or eliminated if the delivery and confinement apertures are chamfered as shown in <FIG>.

In some embodiments, it may be desirable to use multiple passes of a depositor over a substrate to achieve a desired printed feature geometry or arrangement. For example, for a total mass flow rate QD of <NUM> sccm of N<NUM> delivery flow at chamber pressure, the optimal DE spacer length is <NUM>. With a DC distance of <NUM> and a fly height g of <NUM>, features having a FW5M of <NUM> can be printed using a PDC depositor as disclosed herein with delivery and confinement apertures of <NUM> in diameter and exhaust apertures of <NUM> in diameter. Material utilization efficiency of such a device is approximately <NUM>%, which is approximately twice the efficiency that is believed to be achievable with a comparable DEC depositor. However, feature uniformity from the PDC depositor may not be sufficient to permit printing of an electronically useful thin film, such as for use in an OLED as described with respect to <FIG>, in a single pass. Accordingly, in some embodiments a feature may be printed in two or more passes. <FIG> shows a deposition profile resulting from two passes with a PDC depositor as disclosed herein. Two identical features <NUM> that are deposited in separate passes may be offset from each other by a distance <NUM>, thereby causing an overlap to create a composite feature <NUM> with the required thickness uniformity over a desired width about the feature center. The separation distance <NUM> may be determined based upon a calculated or measured feature profile and/or width, such as described with reference to <FIG>.

Alternatively or in addition, a highly-uniform feature may be achieved using a depositor of the kind depicted in <FIG>. In this arrangement, a first delivery aperture <NUM> may be offset from a second delivery aperture <NUM> by a distance Δ <NUM> measured perpendicular to the direction of printing <NUM>. As previously disclosed, two or more exhaust apertures <NUM> may be positioned at equidistant points along the centerline of the depositor, parallel to the direction of printing. Confinement apertures <NUM> as previously disclosed may be positioned on each outer side of each delivery aperture.

The delivery, exhaust, and confinement apertures may be circular, oval, rectangular, or any other desired shape, as previously disclosed. For example, the exhaust apertures <NUM> in this configuration may be square to improve the thickness uniformity of the printed features. A circular exhaust aperture <NUM> may be used to create differing path lengths for delivery flow along the width of the depositor. This directs streamlines of delivery flow towards the centerline of the depositor, creating a more sharply peaked deposition profile and reducing the benefit of distributed delivery apertures.

<FIG> shows deposition profiles for features generated by the depositor configuration shown in <FIG> for a range of delivery aperture separation distances Δ. The scale and position of the features is the same as that used in <FIG>. A comparable feature generated by a depositor having only a single delivery aperture is shown for reference at <NUM>. Feature profiles for delivery aperture separations of <NUM> (<NUM>), <NUM> (<NUM>), <NUM> (<NUM>), and <NUM> (<NUM>) are shown. It has been found that a desired uniformity of <NUM>% can be achieved for a separation distance Δ of <NUM>, with a FW5M of <NUM>.

As previously disclosed, various shapes may be used for delivery, confinement, and exhaust apertures. <FIG> shows an embodiment in which the delivery and confinement apertures are rectangular, so as to provide a more uniform distribution of organic vapor across the width of the depositor. A round delivery aperture configuration as previously shown and described may direct most of the delivery flow towards the center of each aperture. In contrast, a rectangular slit aperture such as the delivery aperture <NUM> may spread organic vapor more evenly across the desired deposition zone. Alternatively or in addition, rectangular confinement apertures <NUM> also may be more effective than round apertures in some embodiments, by providing provides a more rapid transition between the delivery and confinement flows. Alternatively or in addition, rectangular exhaust apertures <NUM> may be used to create uniform path lengths for streamlines of delivery gas as described with respect to <FIG>. In some embodiment, the divider between the delivery apertures <NUM> and confinement apertures <NUM> may be recessed within a pocket in the depositor, so that the delivery and confinement flows enter the gap between the depositor and the substrate as a smooth stream.

<FIG> shows thickness profiles of features deposited by a square aperture depositor for the following configurations: (g =<NUM>, DE =<NUM>) at <NUM>, (g =<NUM>, DE =<NUM>) at <NUM>, (g =<NUM>, DE =<NUM>) at <NUM>, and (g =<NUM>, DE =<NUM>) at <NUM>. It was found that the optimal performance may be obtained at a fly height g of <NUM> and a DE distance of <NUM>. The feature generated by the depositor has a thickness uniformity of <NUM>% and a FW5M of <NUM> (<NUM>). It operates with a material utilization efficiency of η =<NUM>.

In some embodiments, a depositor may include multiple PDC depositor units arranged in a repeating array, so that multiple features can be deposited simultaneously. For example, <FIG> shows an arrangement including multiple depositor configurations <NUM> as shown in <FIG>, arranged in a linear array <NUM> in a single nozzle block. The depositor face of the nozzle block is parallel to the plane of the substrate and the direction of printing is shown at <NUM>. The configuration is analogous to that of the DEC nozzle array shown in <FIG>. The individual depositors may be designed and positioned so as not interfere with each other, so the performance of each depositor is independent of the total array size. Periodicity of the flow field underneath the array may be assumed, though this may be less accurate near the ends of the array. In some embodiments, one or more non-depositing units <NUM> having only exhaust and confinement apertures may be positioned at the ends of the array to reduce or minimize these edge effects on the depositors.

Nozzle blocks including an array of multiple depositors such as shown in <FIG> may be used to print an array of evenly spaced lines for applications such as the emissive layer of an RGB OLED display. It may be preferred in such applications for the depositors to be positioned with the same pitch as the desired printed line array. If this is not possible, depositors may be separated by a multiple of the line pitch at <NUM> so that the line array can be printed in multiple passes. The spacing of the depositor layout also may be selected to account for the thermal expansion of the array that is expected at operating temperature for the materials being deposited. <FIG> shows an arrangement in which confinement apertures may provide confinement gas to a single depositor. Such an arrangement may be suited to microarray designs in which the depositors are spaced at a relatively wide pitch relative to the size of the features they print. The array may include regions for which no confinement flow is needed or desired, such as the separation space <NUM> between depositors, so the gas flow in these regions may remain stagnant. However, it may be desirable for both sides of the delivery flow lane to be sheathed in confinement flow.

Alternatively, a single confinement aperture may be used to provide a confinement flow to multiple depositor arrangements. <FIG> shows a nozzle block in which a confinement aperture <NUM> may provide confinement gas to two adjacent depositors <NUM>. This configuration may be useful for microarray designs in which the feature size is relatively wide relative to the depositor pitch <NUM>. It may reduce the complexity of the nozzle block by minimizing the number of apertures, while permitting depositors to be more closely spaced. The width of the confinement flow is roughly the same as that of the delivery flow, so there no benefit to separating the confinement flow apertures of adjacent depositors if the desired FW5M of the printed feature is greater than <NUM>% of the depositor pitch.

For example, if an array of lines having a FW5M of <NUM> and a pitch of <NUM> is desired, a depositor array having a pitch of <NUM> or a multiple thereof may be used. A depositor array with a pitch of <NUM> can print the lines in a single pass. Such a device may be designed, for example, so that each confinement aperture provides confinement gas to two adjacent depositors. As another example, a depositor array with a pitch of <NUM> would require three passes to print the lines, and likely would be configured so that each confinement aperture provides confinement gas to only one depositor.

The exhaust apertures <NUM> in shown in <FIG> may be a continuous slit stretching extending adjacent depositors. This simplifies both the design and fabrication of the nozzle array. While the divider between delivery and confinement apertures perturbs flow somewhat, there is minimal variation in the inlet and outlet conditions of the flow field in the x direction. If the delivery and confinement gas streams have comparable viscosities, they are defined by differences in composition only and flow field effectively becomes two dimensional. Such a design may be advantageous, for example, for use with an array of densely packed depositors where simplicity of the individual units is desired. It may be disadvantageous in comparison to an array of discrete exhaust apertures, because variation in the flow field along the x axis may be used to counteract diffusive spreading of the vapor in the delivery flow close to the exhaust, as disclosed with respect <FIG>.

<FIG> shows streamlines of gas flow generated by a depositor configuration as shown in <FIG>. In this example, the delivery aperture <NUM> is <NUM> in width and separated from the neighboring confinement aperture by a <NUM> septum <NUM>. The confinement aperture <NUM> between delivery apertures is <NUM> in width, for a depositor pitch of <NUM>. The delivery flow rate <NUM> is <NUM> sccm per depositor and the confinement flow rate <NUM> is <NUM> sccm per depositor. These flow rates may be chosen, for example, so that the flow from the midline of the depositor to the exhaust <NUM> is constant across its width. Flow through the exhaust may be approximately twice the combined delivery and confinement flow. The difference is made up by a secondary confinement flow <NUM> sourced from the gas ambient around the array that flows from the edge of the depositor face <NUM> to the exhaust.

The deposition profile for a feature printed with this depositor arrangement is shown in <FIG>, using the same scale and position as used in <FIG>, with the vertical axis being normalized to the maximum thickness of the printed feature. As shown, it was found that the feature has a FW5M of <NUM>, a uniformity of <NUM>% and a material utilization efficiency of <NUM>% at a fly height g of <NUM>. If the feature is deposited in two passes by depositors offset by <NUM>, a uniformity of <NUM>% can be achieved.

PDC depositors as disclosed herein may be particularly suited for OVJP printing of intermediate-size features. Such features are still sub-millimeter scale individually, but may not require side wall heights in the <NUM>-<NUM> range. At this scale, the transition between adjacent features may be less important than the overall efficiency of deposition. For example, PDC depositors and techniques as disclosed herein may be particularly suited for features not larger than about <NUM>-<NUM>, i.e., features having a largest main-axis dimension in a direction across and parallel to the substrate of not more than about <NUM>-<NUM>.

As previously disclosed, various dimensions may be selected and used for PDC depositor components and nozzle blocks as disclosed herein, depending upon the feature size and resolution desired. In general, it may be desirable for the exhaust aperture(s) to be wider than the delivery aperture(s), at least in part to result in the total mass flow of material being removed via the exhaust apertures is greater than the total being provided through the delivery apertures. That is, it may be desirable for the molar flow of inert gas removed through the exhaust aperture(s) in a PDC depositor or nozzle block to be greater than the total molar flow of inert gas provided by the delivery aperture(s) in the depositor or nozzle block, as previously disclosed. It also may be desirable for the exhaust aperture(s) to have a maximum width as previously defined herein of not more than a desired feature size. For example, the maximum width of exhaust aperture(s) in a PDC depositor or nozzle block as disclosed herein may be <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> or, more generally, any width in the range of about <NUM>-<NUM>.

PDC depositors as disclosed herein may be physically realized by etching a silicon membrane with the desired configuration of delivery, confinement, and exhaust apertures using standard MEMs processing techniques. <FIG> shows an example of such a nozzle array <NUM> as disclosed herein, made from a silicon membrane. Techniques such as deep reactive ion etching or KOH wet etching can be used to produce through-wafer apertures with the desired sidewall profile. Multiple layers of Si can be added behind the membrane provide routing channels to for the apertures. These layers can be attached to the membrane using processes like fusion bonding. The membrane itself can be the device layer of a silicon on oxide (SOI) wafer, supported by a handle layer that is removed by a dissolved wafer process when no longer needed. The membrane may be brazed onto a polished metal backing plate <NUM> fabricated from Kovar or other material with similar thermal expansion properties to Si. An example of this process is described in <CIT>.

The backing plate may be connected to a heated injection block <NUM> containing sublimation sources and a network of channels providing fluid flow to and from the micronozzle array, similar to DEC depositors as previously disclosed. The injection block may have one or more ports <NUM> connecting these channels to the backing plate. The ports and/or their mates on the reverse of the backing plate may be surrounded by glands required for either metal or high temperature elastomer gaskets <NUM>. The compression for these gaskets is supplied by bolts <NUM> that hold the backing plate to the injection block.

It is understood that the various embodiments described herein are by way of example only, and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted with other materials and structures.

Claim 1:
An organic vapor jet printing (OVJP) depositor, comprising:
a delivery aperture (<NUM>) in fluid communication with a source of organic material to be deposited on a substrate and a carrier gas;
a first exhaust aperture (<NUM>) disposed ahead of the delivery aperture (<NUM>) relative to one another with reference to a direction of printing (<NUM>);
a second exhaust aperture (<NUM>) disposed behind the delivery aperture (<NUM>) relative to one another with reference to the direction of printing (<NUM>);
a first confinement gas aperture (<NUM>) disposed laterally adjacent to the delivery aperture (<NUM>) located to either lateral side of the delivery aperture (<NUM>) relative to the direction of printing (<NUM>); and
a second confinement gas aperture (<NUM>) disposed laterally adjacent to the delivery aperture (<NUM>) and opposite the first confinement gas aperture (<NUM>) relative to the first confinement gas aperture (<NUM>),
characterized in that
the delivery aperture (<NUM>) and the first and second exhaust aperture (<NUM>) are aligned such that there is a straight line that overlaps at least a portion of each of the delivery aperture (<NUM>) and the first and second exhaust aperture (<NUM>).