Evaporation source, vacuum deposition system, and method of coating a substrate

Abstract

An evaporation source for depositing a mixed material layer onto a substrate (10) that is arranged in a substrate plane in a vacuum chamber is described. The evaporation source (100) includes: a first vapor distribution pipe (110); a plume shaper arrangement (210); and a second vapor distribution pipe (120). a row of first nozzles (111) and a row of second nozzles (121) are configured to deposit a mixed material layer including the first and second materials onto a substrate that is moved relative to the evaporation source.

Description

EVAPORATION SOURCE, VACUUM DEPOSITION SYSTEM, AND METHOD OF COATING A SUBSTRATETECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to methods and apparatuses for coating substrates with a stack of layers. More particularly, embodiments of the present disclosure relate to evaporation sources and vacuum deposition systems for depositing materials of an OLED layer stack on a substrate. In particular, a metalcontaining layer of an OLED layer stack can be deposited on a substrate, e.g., an electrode layer. Embodiments of the present disclosure specifically relate to evaporation sources and vacuum deposition systems as well as to methods of OLED display manufacturing by thermal evaporation.BACKGROUND

[0002] An organic light-emitting diode (OLED) is a light-emitting diode in which an electroluminescent layer is a film of organic compounds that emits light in response to an electric current. Since OLEDs emit light directly without involving backlight and color filters, the color gamut and viewing angles possible with OLED displays are greater than those of traditional LCD displays. Furthermore, OLEDs can be manufactured on flexible substrates, and, accordingly, they can be utilized in a variety of applications. Organic light emitting diodes (OLEDs) are used in the manufacture of television screens, computer monitors, mobile phones, other hand-held devices, etc., for displaying information. OLEDs can also be used for general space illumination. An OLED display, for example, may include layers of organic material situated between two electrodes that are deposited on a substrate in a manner so as to form a matrix display panel having individually energizable pixels.

[0003] Organic materials and metallic materials are deposited on a substrate in a vacuum processing chamber for OLED manufacturing. Metallic materials areemployed as, for example, electrode materials or electron injection layer (EIL) materials. The materials to be deposited are evaporated using evaporation sources, and the evaporated materials are directed onto a substrate by nozzles. Metallic materials are typically evaporated in an evaporation source at a temperature of 1,000°C or above or 1,500°C or above. Organic materials are typically evaporated in an evaporation source at temperatures between 250°C and 500°C.

[0004] Metallic and organic evaporators can be used for the production of organic light-emitting diodes (OLED). Also, other applications utilize evaporators for depositing metal or organic layers, for example, onto large area substrates. An OLED display may have a plurality of layers of organic material situated between two electrodes that are deposited on a substrate. One of the electrodes can include a transparent conductive layer such as ITO or other transparent conductive oxide materials (TOO). The second electrode can include a metal or a metal alloy.

[0005] OLED pixels can be deposited on a substrate through fine metal masks FMMs (also referred to as pixel masks) that have a plurality of small pixel holes that define individual pixel areas on the substrate. A precise alignment between the FMM and the substrate is necessary for the pixel deposition, which is challenging, since each of the small pixels includes a plurality of layers that are to be deposited on top of each other on a respective anode.

[0006] Another technique for forming OLED pixels on a substrate uses photo lithography to pattern pixels, instead of using fine metal masks (FMMs). Here, a structure that acts as a masking layer is formed directly on the substrate before the actual pixel deposition. Alignment issues can be reduced. However, quickly and reliably coating a substrate with an OLED layer stack without FMMs requires complex equipment and is also challenging.

[0007] In view of the above, improved evaporation sources, vacuum deposition systems, and device manufacturing methods adapted for OLED manufacturing would be beneficial.SUMMARY

[0008] In light of the above, evaporation sources, vacuum deposition systems, and methods of coating a substrate are provided according to the independent claims. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0009] According to an aspect, an evaporation source for depositing a mixed material layer on a substrate arranged in a substrate plane in a vacuum chamber is provided. The evaporation source includes: a first vapor distribution pipe with a row of first nozzles configured to direct first vapor plumes of a first material onto the substrate, the first nozzles respectively having a first nozzle channel defining a first nozzle axis that is tilted relative to a perpendicular to the substrate plane by a first tilt angle (a) of 30° or more; and a second vapor distribution pipe with a row of second nozzles configured to direct second vapor plumes of a second material onto the substrate, the second nozzles respectively having a second nozzle channel defining a second nozzle axis. The evaporation source further includes a plume shaper arrangement configured to laterally limit the first vapor plumes emitted by the first nozzles to provide, in a respective sectional plane defined by the first nozzle axis and the perpendicular to the substrate plane, a maximum impingement angle (amax) of the first vapor plumes of 50° or more and 85° or less, and a minimum impingement angle (amin) of the first vapor plumes of more than 0° and less than 30° relative to the perpendicular to the substrate plane. The row of first nozzles and the row of second nozzles are configured to deposit, by co-deposition, a mixed material layer including the first and second materials onto a substrate that is moved relative to the evaporation source.

[0010] Therein, the angle values are either respectively measured in a counterclockwise manner relative to the perpendicular to the substrate plane or are respectively measured in a clockwise manner relative to the perpendicular, i.e., a “mirrored” setup is covered as well. In particular, the plume shaper arrangement is configured to laterally limit the first vapor plumes so that the first material impacts on the substrate on only one side of an “orthogonal plane”, that is perpendicular to the substrate plane and intersects the row of first nozzles. Expressed differently, in the sectional plane that is defined by the first nozzle axis and the perpendicular (SN) to thesubstrate plane, the trajectories of the vapor particles of the first material impinging on the substrate are all tilted in the same direction relative to the perpendicular (SN), e.g., all tilted to the right or all tilted to the left relative to the perpendicular (SN). The amount of deposition of the first material behind an overhang that is provided on the substrate can be increased in relation to the amount of deposition of the first material on uncovered regions of the substrate.

[0011] In some embodiments, the first nozzle channels of the first nozzles and / or the second nozzle channels of the second nozzles respectively have a cross-sectional area of at least 0.5 mm2, in particular 1 mm2or more. In particular, the first nozzle channels and / or the second nozzle channels have a round, or circular cross-sectional shape, particularly with a nozzle channel diameter of at least 2 mm, e.g., in a range from 2 mm to 5 mm.

[0012] According to an aspect, an evaporation source for depositing a mixed material layer on a substrate arranged in a substrate plane in a vacuum chamber is provided. The evaporation source includes: a first vapor distribution pipe with a row of first nozzles configured to direct first vapor plumes of a first material onto the substrate, the first nozzles respectively having a first nozzle channel defining a first nozzle axis that is tilted relative to a perpendicular (SN) to the substrate plane by a first tilt angle (a); and a second vapor distribution pipe with a row of second nozzles configured to direct second vapor plumes of a second material onto the substrate, the second nozzles respectively having a second nozzle channel defining a second nozzle axis. The evaporation source further includes a plume shaper arrangement configured to laterally limit at least the first vapor plumes emitted by the first nozzles, so that the first material impacts on the substrate on only one side of an orthogonal plane that is perpendicular to the substrate plane and intersects the row of first nozzles, and so that a mixed material layer comprising the first and second materials is deposited onto the substrate.

[0013] According to another aspect, a vacuum deposition system is provided. The vacuum deposition system includes a vacuum chamber, an evaporation source according to any of the embodiments described herein in the vacuum chamber, and a substrate transportation track configured to move a substrate in the substrate planealong a substrate transport path past the evaporation source.

[0014] The vacuum deposition system may optionally further include a shield transportation track between the substrate transportation track and the evaporation source configured to move a movable shield in front of the substrate for shielding an edge region of the substrate.

[0015] According to another aspect, a method of coating a substrate in a vacuum chamber with an evaporation source is provided, the evaporation source including a first vapor distribution pipe and at least a second vapor distribution pipe. The method includes directing first vapor plumes of a first material onto the substrate with a row of first nozzles of the first vapor distribution pipe, the first nozzles respectively having a first nozzle channel defining a first nozzle axis that is tilted relative to a perpendicular to the substrate plane by a first tilt angle (a) of 30° or more; laterally limiting the first vapor plumes with a plume shaper arrangement to provide, in a respective sectional plane defined by the first nozzle axis and the perpendicular to the substrate plane, a maximum impingement angle (amax) of the first vapor plumes of 50° or more and 85° or less, and a minimum impingement angle (amin) of the first vapor plumes of more than 0° and less than 30° relative to the perpendicular to the substrate plane; directing second vapor plumes of a second material onto the substrate with a row of second nozzles of the second vapor distribution pipe, the second nozzles respectively having a second nozzle channel defining a second nozzle axis; and moving the substrate past the evaporation source to deposit a mixed material layer comprising the first material and the second material on the substrate.

[0016] According to an aspect, a method of coating a substrate in a vacuum chamber with an evaporation source is provided, the evaporation source including a first vapor distribution pipe and at least a second vapor distribution pipe. The method includes directing first vapor plumes of a first material onto the substrate with a row of first nozzles of the first vapor distribution pipe, the first nozzles respectively having a first nozzle channel defining a first nozzle axis that is tilted relative to a perpendicular to the substrate plane by a first tilt angle (a); directing second vapor plumes of a second material onto the substrate with a row of second nozzles of the second vapor distribution pipe, the second nozzles respectively having a second nozzle channeldefining a second nozzle axis; and moving the substrate past the evaporation source to deposit a mixed material layer comprising the first material and the second material on the substrate. The first vapor plumes emitted by the first nozzles are laterally limited with a plume shaper arrangement so that the first material impacts on the substrate on only one side of an orthogonal plane that is perpendicular to the substrate plane and intersects the row of first nozzles.

[0017] According to another aspect, an OLED display device is provided that includes a layer stack with a plurality of layers, wherein the OLED display device is manufactured according to any of the methods and / or using any of the deposition systems described herein. The layer stack includes a mixed material layer manufactured as described herein.

[0018] In particular, the substrate of the OLED display device may have a structure formed thereon comprising a sidewall adjacent to a pixel region and an overhang projecting from the sidewall. The mixed material layer may be a cathode layer of an OLED layer stack that includes two co-deposited metals, the cathode layer reaching below the overhang to contact the sidewall at a position below the overhang.

[0019] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. The method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments are also directed at methods for operating the described apparatus. The methods for operating the described apparatuses include method aspects for carrying out every function of the apparatus. Embodiments are also directed at methods of manufacturing processed substrates, particularly coated substrates, in a vacuum deposition system described herein, and substrates manufactured in accordance with the methods and / or using the systems described herein, such as OLED substrates, particularly OLED displays. Also, other devices than OLED displays can be manufactured with the apparatuses and methods described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following:

[0021] FIG. 1 shows a schematic view of a vacuum deposition system with an evaporation source according to embodiments;

[0022] FIG. 2 shows a schematic side view of an evaporation source according to embodiments;

[0023] FIG. 3 shows a schematic view of an evaporation source according to embodiments in a horizontal sectional plane;

[0024] FIG. 4 shows a schematic view of an evaporation source according to embodiments in a horizontal sectional plane;

[0025] FIG. 5 is a flow diagram illustrating a coating method according to embodiments; and

[0026] FIG. 6 shows a schematic sectional view of a substrate with an OLED layer stack manufactured according to methods of the present disclosure.DETAILED DESCRIPTION

[0027] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations. Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individualembodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment can apply to a corresponding part or aspect in another embodiment as well.

[0028] OLED pixels can be formed on a substrate using photo lithography and patterning, particularly without a fine metal mask (FMM). An FMM has a plurality of pixel holes and is positioned in front of the substrate and aligned relative to the substrate before the material deposition, so that individual pixels can be deposited onto the substrate. OLED pixel patterning without FMMs is based on a structure that acts as a “mask” and is formed directly on the substrate before coating the substrate with a plurality of materials in a vacuum deposition system. The structure that is formed on the substrate may include sidewalls adjacent to pixel regions, particularly sidewalls surrounding the pixel regions, and overhang structures projecting from the sidewalls at least partially over the pixel regions, as is exemplarily depicted in FIG. 6.

[0029] FIG. 6 is a schematic sectional view showing a part of an OLED layer stack 760 on a substrate 10 manufactured with OLED pixel patterning techniques. Adjacent pixel-defining layer (PDL) structures 715 are formed on an upper surface of the substrate 10 that define pixel regions 13, and overhang structures 720 are disposed on the PDL structures 715. The overhang structures 720 may include a lower portion 720B with a sidewall and an upper portion 720A with an overhang protruding from the lower portion 720B partially over the pixel region 13. In FIG. 6, a sidewall 11 adjacent to a pixel region 13 is schematically depicted, and an overhang 12 projects from the sidewall 11 partially over the pixel region 13. As will be appreciated, the pixel region 13 may be surrounded by two or more sidewalls, and overhangs may be formed on the two or more sidewalls and project partially over the pixel region from different sides. In particular, the pixel region 13 may be surrounded by sidewalls with protruding overhangs on four sides thereof.

[0030] By depositing various materials on the pixel regions to defined positions under the overhangs, in combination with subsequent etching / patterning, individually switchable pixels can be formed on the substrate. The deposition of metals and organic layers in predetermined regions, particularly under the overhangs, is challenging.

[0031] The lower portion 720B with the sidewall 11 may be made of a conductive material meant to be in contact with a cathode layer 711 of the OLED layer stack 760, and may allow an electrical connection of the cathode layer 711 with a cathode potential. Alternatively or additionally, at least a part of the sidewall 11 may include an assistant cathode 716 meant to be in electrical contact with the cathode layer 711 of the OLED layer stack. The upper portion 720A that forms the overhang may be made of a non-conductive inorganic material or alternatively of a conductive inorganic material.

[0032] The OLED layer stack 760 generally includes, in the following order, an anode layer 714, a hole injection layer 718, at least one organic layer 713 (made of one or more optically active organic materials), an electron injection layer 712, the cathode layer 711, and at least one encapsulation layer 710. Further layers, e.g., an electron transport and / or a hole transport layer may also be provided.

[0033] As is shown in FIG. 6, the at least one organic layer 713 does not contact the sidewall 11 , and the cathode layer 711 contacts the sidewall 11 under the overhang 12. For ensuring that the organic layer does not substantively contact the sidewall 11 under the overhang, the at least one organic layer 713 may be deposited with an organic vapor plume 732 having a small opening angle, particularly a smaller opening angle than a metal vapor plume 731 of a subsequently deposited metal layer. For ensuring that the cathode layer 711 reliably contacts the sidewall 11 under the overhang, the cathode layer may be deposited with a metal vapor plume 731 having a large opening angle. However, vapor plumes with large opening angles may not always be beneficial, for example, because a vapor plume with a large opening angle causes a substantial shadowing effect in several directions that leads to stray coating on regions of the deposition system and on the substrate that should not be coated. Further, a large opening angle may lead to a large coating thickness in uncovered regions of the substrate as compared to a coating thickness below the overhang 12.

[0034] In view of the above, according to embodiments described herein, methods and apparatuses are described that allow a reliable deposition of OLED layer stacks on substrates, particularly on substrates with overhang structures formed thereon. Some of the methods and apparatuses described herein ensure or improve anelectrical contact of a cathode layer 711 with a conductive sidewall under an overhang 12, by providing a comparatively large layer thickness of the cathode layer below the overhang 12. Generally, a low contact resistance and a large contact area between the cathode layer and the conductive sidewall is beneficial, e.g., in order to reduce or prevent an influence of a poor cathode contact on the l-V-curve of the manufactured OLED device.

[0035] The embodiments described herein provide an evaporation source configured to quickly and reliably deposit two or more materials onto the substrate, particularly for coating the substrate with a mixed-material layer, while ensuring that a predetermined amount of material is deposited under an overhang, e.g., for providing a reliable cathode contact. Furthermore, a vacuum deposition system with one or more evaporation sources as described herein is compact, cost effective and has a small footprint. The embodiments described herein can be used for depositing layers of an OLED layer stack on a substrate having an overhang structure formed thereon. The embodiments described herein can also be used for other applications, e.g., for the deposition of OLED layer stacks through pixel masks or fine metal masks, and / or for the deposition of material layers on other substrates, e.g., semiconductor substrates.

[0036] FIG. 1 shows a vacuum deposition system 1000 with an evaporation source 100 according to embodiments described herein in a schematic top view. The vacuum deposition system 1000 includes a first vacuum chamber 1001 that houses an evaporation source 100 as described herein, and, optionally, one or more further vacuum chambers that may house one or more further evaporation sources, e.g., a second evaporation source 102 and / or a third evaporation source 103. The vacuum deposition system 1000 may include at least five or at least ten evaporation sources, for coating the substrate with a plurality of layers in succession. The evaporation sources may be configured to coat vertically or essentially vertically oriented substrates that are transported past the evaporation sources on a substrate transportation track 1013. A plurality of materials, that may include one or more metals and / or one or more organic materials, can be deposited in succession onto the substrate for providing a layer stack on the substrate, particularly an OLED layer stack. For example, the vacuum deposition system 1000 may include ten or more evaporation sources for coating the substrate with a plurality of layers.

[0037] In the present disclosure, a "vacuum deposition system" is to be understood as a system or arrangement configured for vacuum deposition of materials on a substrate. A "vacuum chamber" or “vacuum processing chamber” is to be understood as a chamber configured for vacuum deposition. The term "vacuum", as used herein, can be understood in the sense of a technical vacuum having a vacuum pressure of less than, for example, 10 mbar. Typically, the pressure in a vacuum chamber as described herein may be between 10-5 mbar and about 10-8 mbar, particularly between 10-5 mbar and 10-7 mbar.

[0038] The vacuum deposition system 1000 may include a substrate transportation track 1013 configured to move a substrate 10 along a substrate transport path T past the evaporation source 100 and past the optional further evaporation sources. The substrate transportation track 1013 may extend at least partially through the first vacuum chamber 1001 and through the optional further vacuum chambers and may include a substrate transportation system configured for substrate transport, e.g., a roller transportation system, one or more linear motors and / or a magnetic levitation system suitable for moving the substrate relative to and past the evaporation sources. The substrate may be carried by a substrate carrier 1020 during the transport and / or deposition.

[0039] The vacuum deposition system 1000 may optionally further include a shield transportation track 1012 extending between the substrate transportation track 1013 and the evaporation source 100 in the first vacuum chamber 1001. The shield transportation track 1012 is configured to move a movable shield 1030 in front of the substrate 10 for shielding one or more edge regions of the substrate 10 and / or for shielding at least parts of a substrate carrier 1020 that carries the substrate 10. The movable shield 1030 may be a movable edge exclusion shield with a shielding frame for covering one or more edge regions of the substrate. The shield transportation track 1012 may be located between the substrate transportation track 1013 and the evaporation source 100 in the first vacuum chamber 1001 and may include a shield transportation system, e.g., a roller transportation system, one or more linear motors and / or a magnetic levitation system suitable to move the movable shield 1030 in front of the substrate 10, such that one or more edge regions of the substrate are covered during coating with the evaporation source 100, as is schematically depicted in FIG. 1.

[0040] The movable shield 1030 may be movable back and forth on the shield transportation track 1012, as is schematically indicated by respective arrows in FIG. 1 , such that subsequent substrates moved along the substrate transport path T can be shielded by the movable shield 1030 during coating with the evaporation source 100. Each evaporation source may have an associated movable shield that is movable back and forth on a (respective) shield transportation track for shielding an edge region of the substrate from being coated when the substrate is moved past the respective evaporation source.

[0041] Accordingly, an in-line system is provided that allows the deposition of a plurality of layers on a substrate in succession, while the substrate is moved through the vacuum deposition system 1000 past a plurality of evaporation sources.

[0042] Embodiments described herein particularly relate to deposition of materials, e.g. for display manufacturing on large area substrates. According to some embodiments, large area substrates or carriers supporting one or more substrates may have a size of 0.5 m2or larger, particularly of 1 m2or larger. For instance, the deposition system may be adapted for processing large area substrates, such as substrates of GEN 4.5, which corresponds to approximately 0.67 m2of substrate (0.73x0.92m), GEN 5, which corresponds to approximately 1.4 m2substrates (1.1 m x 1.3 m), GEN 6, which corresponds to approximately 2.7 m2(1.5 m x 1.8 m), GEN 7.5, which corresponds to approximately 4.29 m2substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to approximately 5.7 m2substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to approximately 8.7 m2substrates (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding substrate areas can similarly be implemented. According to yet further implementations, half-sizes of the above-mentioned substrate generations can be processed. Alternatively or additionally, semiconductor wafers may be processed and coated in deposition systems according to the present disclosure.

[0043] FIG. 2 shows an evaporation source 100 according to embodiments described herein in a side view (partially illustrated as a sectional view). In the present disclosure, an "evaporation source " is to be understood as an arrangement configured for material deposition on a substrate by evaporation. The evaporation source 100 hascrucibles 222 configured to evaporate same or different source materials to be deposited onto the substrate and vapor distribution pipes configured to direct the evaporated source materials towards the substrate through a plurality of nozzles. For instance, a vapor distribution tube or vapor distribution pipe may provide a line source with a plurality of nozzles that are arranged in a row (or “line array”), one above the other, along a longitudinal direction of the vapor distribution pipe. The row of nozzles may be provided along a longitudinal direction (typically an essentially vertical direction) of the vapor distribution pipe to provide an essentially vertical line source. Each vapor distribution pipe may have at least one row of nozzles, particularly one single vertical nozzle row suitable to coat substrates having an essentially vertical orientation.

[0044] An “essentially vertical direction” as used herein relates to a direction that corresponds to the direction of gravity or deviates from the direction of gravity by less than 10°.

[0045] For instance, the source material to be deposited may be an inorganic material, particularly a metallic material for use as an electrode material or an electron transport layer material in an OLED layer stack.

[0046] As is schematically depicted in FIG. 2, the evaporation source 100 includes a first vapor distribution pipe 110 and (at least) a second vapor distribution pipe 120 arranged next to each other and configured to co-deposit a mixed material layer onto the substrate. An optional further vapor distribution pipe of the evaporation source 100 is not shown in the schematic view of FIG. 2, but is shown, e.g., in the sectional view of FIG. 4. The first vapor distribution pipe 110 has a row of first nozzles 111 that may be arranged along the longitudinal direction of the first vapor distribution pipe 110, e.g., above one another in an essentially vertical line array. The evaporation source may be a line source for substrate coating in an essentially vertical orientation. The evaporation source may be configured to deposit two or three materials onto the substrate with two, three or more vapor distribution pipes arranged next to each other.

[0047] The row of first nozzles 111 includes a plurality of nozzles, particularly twenty or more nozzles. Each nozzle has a main evaporation direction that is defined by the direction of the nozzle channel of the respective nozzle. A substantially cone-shaped vapor plume emitted by a nozzle is generally centered around the nozzle axis of the nozzle, e.g., with a maximum of vapor particles of the plume propagating along the nozzle axis. Specifically, a vapor plume emitted by a nozzle is defined by the nozzle axis and by the opening angle of the plume. A vapor plume can be rotationally symmetrical with respect to the nozzle axis, and / or a vapor plume can be shaped by one or more shaping edges of a “plume shaper arrangement” to be symmetrical or to be asymmetrical relative to the nozzle axis.

[0048] The first nozzles 111 of the row of first nozzles are configured to direct first vapor plumes of a first material onto the substrate. The first nozzles 111 respectively have a first nozzle channel 112 that defines a respective first nozzle axis M1 that is tilted relative to a line extending from the first nozzle and perpendicularly intersecting the substrate plane (referred to herein as a “perpendicular to the substrate plane (SN)”, illustrated in FIG. 3). The first nozzle channels 112 of the first nozzles 111 may be essentially parallel to each other and arranged one above the other in one vertical plane. Specifically, the first nozzles axes M1 of the first nozzles 111 may all intersect the substrate plane at the same or at a similar angle, which is a tilted angle (see the sectional views of FIG. 3 and FIG. 4).

[0049] The second nozzles 121 of the second vapor distribution pipe 120 are configured to direct second vapor plumes of a second material onto the substrate. The second nozzles 121 respectively have a second nozzle channel that defines a respective second nozzle axis M2. The second nozzle channels and the second nozzle axes M2 of the second nozzles 121 may be essentially parallel to each other and arranged one above the other in one vertical plane. Specifically, the nozzles axes M2 of the second nozzles 121 may all intersect the substrate plane at the same angle, which is optionally, but not necessarily, tilted. For example, as is schematically shown in FIG. 3, the second nozzle axes M2 of the second nozzles 121 may intersect the substrate plane SP essentially perpendicularly.

[0050] FIG. 3 shows a schematic view of an evaporation source 100 according to embodiments described herein in a horizontal sectional (X). The evaporation source 100 is configured to coat a substrate 10 that is arranged in a substrate plane (SP), in particular, a substrate 10 that is moved past the evaporation source 100 in thesubstrate plane (SP) along a substrate transport path T. The evaporation source 100 includes a first vapor distribution pipe 110 with a row of first nozzles 111 configured to direct first vapor plumes of a first material onto the substrate 10 and at least a second vapor distribution pipe 120 with a row of second nozzles 121 configured to direct second vapor plumes of the second material onto the substrate 10. The first nozzles 111 have a first nozzle channel 112 that defines a first nozzle axis M1 , respectively, and the second nozzles 121 have a second nozzle channel 122 that defines a second nozzle axis M2, respectively.

[0051] The first nozzle axes of the row of the first nozzles 111 may be arranged parallel to each other in the same plane, in particular, one above the other in a first vertical plane. The second nozzle axes of the row of the second nozzles 121 may be arranged parallel to each other in the same plane, in particular, one above the other in a second vertical plane. The first vertical plane and the second vertical plane may be different planes that intersect each other, as is schematically depicted in the sectional view of FIG. 3 that shows the first nozzle axis M1 of one of the first nozzles and the second nozzle axis M2 of one of the second nozzles intersecting each other.

[0052] As is depicted in FIG. 3, the row of first nozzles 111 and the row of second nozzles 121 are configured to deposit a mixed material layer that includes both the first material and second materials onto the substrate, when the substrate is moved relative to the evaporation source, particularly when the substrate is moved past the first and second vapor distribution pipes along the substrate transport path T.

[0053] As is further depicted in FIG. 3, the first nozzle channel M1 and the second nozzle channel M2 may be tilted toward each other to enable a co-deposition of the mixed material layer onto the substrate. In particular, the first and second nozzle axes may be inclined toward one another, particularly to hit the substrate on overlapping or corresponding deposition spots for enabling the co-deposition of the mixed material layer.

[0054] In some embodiments, which can be combined with other embodiments described herein, the substrate 10 has a structure formed thereon that includes a sidewall 11 adjacent to a pixel region 13 and an overhang 12 that projects from the sidewall 11 at least partially over the pixel region 13. The first nozzle axis M1 and, inparticular, the entirety of the first vapor plume emitted by the first nozzle, may be tilted relative to a perpendicular (SN) from the first nozzle to the substrate plane (SP) to increase the amount of the first material deposited below the overhang 12, in particular, to ensure or to improve a contact between the first material and the sidewall 11 below the overhang 12.

[0055] FIG. 3 shows the evaporation source 100 in a (horizontal) sectional plane (X) essentially perpendicular to the substrate plane (SP), wherein the sectional plane (X) intersects one of the first nozzles of the row of first nozzles 111. The sectional plane (X) is defined by the first nozzle axis M1 of said first nozzle and by the perpendicular to the substrate plane (SN) from said first nozzle. It is to be understood that the setup of the evaporation source and the plume opening angles in other sectional planes that intersect through other first nozzles of the row of first nozzles are similar or corresponding to the sectional plane (X) shown in FIG. 3, so that explanations related to one of the first nozzles may apply, mutatis mutandis, to the other first nozzles of the row of first nozzles 111.

[0056] As is schematically depicted in FIG. 3, according to embodiments described herein, the first nozzle axis M1 that is defined by the first nozzle channel 112 is tilted relative to the perpendicular (SN) to the substrate plane (SP) by a first tilt angle a, particularly by a first angle a of 30° or more and 90° or less, particularly 45° or more and 70° or less, more particularly 50° or more and 55° or less. A tilted nozzle axis M1 of the first nozzles 111 can increase the deposition amount of the first material below the overhang 12, in particular to ensure or improve a contact between the first material (which may be a conductive material of a cathode layer, such as a metal) and the sidewall 11 below the overhang 12 (which may provide a cathode contact).

[0057] The angle values - as used herein - are either respectively measured in a counterclockwise manner (e.g., relative to the perpendicular to the substrate plane) or are respectively measured in a clockwise manner. For example, in FIG. 3, the angles amaxOmin, a are respectively measured in a counterclockwise manner, but a “mirrored” setup, with the first nozzles 111 tilted toward the right side of the perpendicular SN, is covered as well by the angle values as described herein. Specifically, the embodiments described herein encompass a “mirrored” setup, in which, e.g., the first nozzles aredirected to the right side and the substrate transport direction T is inverted.

[0058] In particular, by tilting the first nozzles such that the first nozzle axis M1 is respectively directed toward an area of the substrate below the overhang 12, a ratio between an amount of first material deposited below the overhang 12 and an amount of first material deposited on uncovered regions of the substrate can be increased, e.g., for improving an electrical contact of a cathode layer and / or for increasing a thickness of the cathode layer below the overhang where a cathode contact may be formed.

[0059] In addition, according to embodiments described herein, a plume shaper arrangement 210 is provided that may be arranged at least partially in front of the vapor distribution pipes, particularly between the vapor distribution pipes and the substrate plane (SP). The plume shaper arrangement 210 is configured to laterally limit at least the first vapor plumes emitted by the first nozzles 111, particularly on two opposite lateral sides thereof. Specifically, edge portions of the first vapor plumes on a first lateral side and on a second lateral side may be blocked by respective shaping edges of the plume shaper arrangement 210 to provide first vapor plumes impinging on the substrate in a predetermined angular range between a minimum impingement angle aminand a maximum impingement angle amax.

[0060] The plume shaper arrangement 210 may be configured to limit the first vapor plumes emitted by the first nozzles 111 to provide, in the respective sectional plane (X), a maximum impingement angle amaxof the first vapor plumes of 50° or more and 85° or less relative to the perpendicular (SN) to the substrate plane (SP) and a minimum impingement angle aminof the first vapor plumes of more than 0° and less than 30° relative to the perpendicular (SN) to the substrate plane (SP). The “minimum impingement angle” can be understood as the smallest angle relative to the perpendicular (SN) - in the sectional plane (X) - at which vapor particles emitted by the first nozzle impact on the substrate. The “maximum impingement angle” can be understood as the largest angle relative to the perpendicular (SN) - in the sectional plane (X) - at which vapor particles emitted by the first nozzle impact on the substrate. The “minimum impingement angle” amin, the “maximum impingement angle” amaxand the tilt angle a can respectively be measured in a counterclockwise manner (as in FIG.3) or in a clockwise manner relative to the perpendicular (SN) and are larger than zero, i.e. , the whole first vapor plume from its maximum angle to its minimum angle, is tilted relative to the perpendicular (SN) toward one side, which can increase a deposition amount of the first material below the overhang 12, as it is schematically depicted in FIG. 3.

[0061] In particular, the plume shaper arrangement 210 is configured to laterally limit the first vapor plume emitted by the first nozzle to provide, in the sectional plane (X) shown in FIG. 3 that is defined by the first nozzle axis M1 and the perpendicular (SN), trajectories of the vapor particles of the first material impinging on the substrate that are all tilted toward the same side relative to the perpendicular (SN), e.g., all trajectories tilted toward the left side or all trajectories tilted toward the right side relative to the perpendicular (SN).

[0062] In particular, an impact of vapor particles emitted from the first nozzle on the substrate on both sides of the perpendicular (SN) can be avoided by (i) the tilt of the first nozzle axis M1, particularly to point into an inclined direction below the overhang 12 and (ii) by the plume shaper arrangement 210 that ensures a minimum and a maximum impingement angle on the same side of the perpendicular (SN) and / or, that ensures that the whole vapor plume is inclined relative to the perpendicular (SN), particularly to point in a direction below the overhang 12.

[0063] According to embodiments described herein, the plume shaper arrangement 210 is configured to laterally limit the first vapor plumes emitted by the first nozzles in such a way that the first material impacts on the substrate on only one side of an “orthogonal plane” that is perpendicular to the substrate plane (SP) and intersects the row of first nozzles 111. In FIG. 3, said “orthogonal plane” is a plane perpendicular to the paper plane that includes the perpendicular (SN). As is shown in FIG. 3, the first vapor plumes are partially blocked by the plume shaper arrangement 210 in such a way that the first vapor plumes are completely located on only one side of said “orthogonal plane”.

[0064] An inclination of the first nozzle axis M1 in combination with an inclination of each of the vapor trajectories of the first vapor plume toward the same side relative to said “orthogonal plane” can further increase a deposition amount of the first materialbelow the overhang 12 and can improve a cathode contact below the overhang.

[0065] In some embodiments, which can be combined with other embodiments described herein, the first nozzle axis M1 of the first nozzles is respectively tilted relative to the perpendicular (SN) by the first tilt angle a of 30° or more, more particularly 45° or more and 70° or less, more particularly 50° or more and 55° or less. Alternatively or additionally, the plume shaper arrangement 210 is configured to limit the first vapor plumes on a first lateral side to provide, in the respective sectional plane (X), a maximum impingement angle amaxof the first vapor plumes of 50° or more and 85° or less, particularly 60° or more and 80° or less, more particularly about 70°, relative to the perpendicular (SN). Alternatively or additionally, the plume shaper arrangement 210 is configured to limit the first vapor plumes on a second lateral side to provide, in the respective sectional plane (X), a minimum impingement angle amin>0°, particularly of 5° or more and / or 25° or less, more particularly about 10°, relative to the perpendicular (SN).

[0066] A first tilt angle a of the first nozzle axis M1 of the first nozzles 111 in the angular range mentioned above and a maximum impingement angle amaxin the angular range mentioned above are beneficial, because a considerable amount of the first material can be deposited below an overhang 12 and, at the same time, a relatively compact deposition area and an acceptable shadowing effect are provided. Further, a minimum impingement angle amin>=0° is beneficial, so that the whole vapor plume is inclined relative to the perpendicular (SN) toward the same side pointing below an overhang, further increasing the deposition amount below the overhang 12.

[0067] However, if the minimum shaping angle aminis too large relative to the first tilt angle a of the first nozzle axis M1 , too much material would be blocked by the plume shaper arrangement 210, which would unnecessarily increase the material consumption. The angle ranges for the tilt angle and the minimum and maximum shaping angles as described herein provide a high deposition amount below the overhang while reducing an unnecessary loss of material being blocked by the shaper arrangement. Accordingly, the nozzle tilt in combination with the shaper arrangement described herein can be beneficial with regard to a good cathode contact and at the same time an acceptable material utilization.

[0068] In some embodiments, which can be combined with other embodiments described herein, the first nozzle channel 112 of the first nozzles 111 respectively has a cross-sectional area of at least 0.5 mm2, particularly of at least 1 mm2or more. In particular, each of the first nozzle channels of the first nozzles may have a cross-sectional area of at least 1 mm2, and optionally of 20 mm2or less. A cross-sectional area above 0.5 mm2can ensure a sufficiently large flow of vapor from each of the first nozzles toward the substrate, while the opening angle of the vapor plumes emanating from the first nozzles is sufficiently large to provide the maximum and minimum impingement angles specified herein. The cross-sectional area of the nozzle channels can generally vary between a nozzle inlet and a nozzle outlet, wherein the “cross-sectional area” of the nozzle channel as used herein can be understood as the minimum cross-sectional area of the nozzle channel between the respective nozzle inlet and the respective nozzle outlet that defines the flow of vapor through the nozzle channel. The second nozzles channels of the second nozzles can be designed accordingly.

[0069] In some embodiments, the first nozzle channel 112 is an at least partially tubular, particularly an at least partially cylindrical nozzle channel, particularly having a round or circular cross-sectional shape, more particularly with a (minimum) channel diameter of 2 mm or more and 5 mm or less. The first nozzle channel can optionally widen toward the nozzle outlet. The vapor plumes emitted by nozzles having a round nozzle channel with a channel diameter of at least 2 mm provide a sufficient vapor flow toward the substrate. Further, the emitted vapor plumes have an opening angle that is sufficiently large to provide the maximum and minimum impingement angles specified herein. The second nozzles channels of the second nozzles can be designed accordingly.

[0070] In some embodiments, which can be combined with other embodiments described herein, the plume shaper arrangement 210 is further configured to laterally limit the second vapor plumes emitted by the second nozzles 121 , particularly on two lateral sides of the respective second nozzle axis M2, to provide a partial or an essentially full overlap between a first area in the substrate plane (SP) covered by the first vapor plumes and a second area in the substrate plane (SP) covered by the second vapor plumes. As is schematically depicted in FIG. 3, the first area that iscovered by the first vapor plumes in the substrate plane (SP) and the second area that is covered by the second vapor plumes in the substrate plane (SP) substantially or completely overlap with each other, particularly providing an overlap ratio of 80% or more, or 90% or more, or even a full overlap. A mixed material layer that includes both the first and the second material in a uniform distribution or mixing on the substrate can be deposited on the substrate.

[0071] The plume shaper arrangement 210 can limit the second vapor plumes on a first lateral side and on a second lateral side opposite the first lateral side so that the second vapor plumes can impinge on the substrate synchronously with the first vapor plumes and cover essentially the same area on the substrate. Specifically, a first shaping edge of the plume shaper arrangement 210 may laterally limit the second vapor plumes on a first side, and a second shaping edge of the plume shaper arrangement 210 may laterally limit the second vapor plumes on a second side, as it is schematically depicted in FIG. 3.

[0072] In some embodiments, which can be combined with other embodiments described herein, the second nozzle axis M2 of the second nozzles may be essentially perpendicular to the substrate plane (SP) or may have a tilt angle of 20° or less relative to a perpendicular to the substrate plane. As is schematically depicted in FIG. 3, since the second nozzle axis M2 is essentially perpendicular to the substrate plane, a major part of the second material hits the substrate at relatively small angles relative to the perpendicular (SN) in an angular range from, e.g. -20° to +20°, so that a ratio between the amount of second material deposited below the overhang 12 and the amount of second material deposited on uncovered regions of the substrate may be small compared to the first material, e.g., 50% or less.

[0073] In some embodiments, which can be combined with other embodiments described herein, the plume shaper arrangement 210 includes a first vapor plume shaper 211 that is connected to at least one of the first and second vapor distribution pipes and has at least a first shaping edge 213 for laterally limiting the first vapor plumes and a second shaping edge 214 for laterally limiting the second vapor plumes.

[0074] The first vapor plume shaper 211 may be mounted at the first vapor distribution pipe and / or, at the second vapor distribution pipe and may be arrangedadjacent to the first nozzles and / or the second nozzles. Optionally, the first vapor plume shaper 211 may be thermally isolated from the first and / or second vapor distribution pipes, so that vapor material that is blocked by the first vapor plumes shaper 211 condenses on the first vapor plume shaper 211 to adhere thereon. In some embodiments, the first vapor plume shaper 211 may be actively or passively cooled to maintain a temperature below an evaporation temperature of the evaporated materials, e.g., a temperature of 200°C or less.

[0075] The first and / or second nozzles may, at least partially, protrude into or through openings or slits of the first vapor plume shaper 211, as it is schematically depicted in FIG. 3. In particular, a distance between a first shaping edge 213 of the first vapor plume shaper 211 and the first nozzles may be 10 cm or less, and / or a distance between the second shaping edge 214 of the first vapor plume shaper 211 and the second nozzles may be 10 cm or less. The first and / or second shaping edges may be shaping edges that extend linearly along the rows of first and second nozzles to laterally shape each of the first and second vapor plumes emitted by the rows of first and second nozzles.

[0076] In some implementations, the first vapor plume shaper 211 has the first shaping edge 213 that is configured to laterally limit the first vapor plumes on a side adjacent to the second vapor distribution pipe 120 and the second shaping edge 214 configured to laterally limiting the second vapor plumes on a side adjacent to the first vapor distribution pipe 110. Specifically, the first vapor plume shaper 211 may be at least partially arranged between the first vapor plumes and the second vapor plumes during operation of the evaporation source to limit inner areas of the first and second vapor plumes that first intersect with each other downstream of the first vapor plume shaper 211.

[0077] Optionally, the first vapor plumes shaper 211 may also have a third shaping edge configured to laterally limit the first vapor plumes on a side opposite to the second vapor distribution pipe 120 and / or, a fourth shaping edge configured to laterally limit the second vapor plumes on a side opposite to the first vapor distribution pipe 110.

[0078] In some embodiments, which can be combined with other embodiments described herein, the plume shaper arrangement 210 includes a shaper wall 212 thatis arranged separately from the first and second vapor distribution pipes and has at least one of a first shaper wall edge for laterally limiting the first or second vapor plumes and a second shaper wall edge for laterally limiting the first or second vapor plumes. For example, the shaper wall 212 has a first shaper wall edge for laterally limiting the first vapor plumes and / or, a second shaper wall edge for laterally limiting the second vapor plumes, or vice versa.

[0079] The shaper wall 212 may include at least two wall elements with a slit arranged therebetween, particularly a vertically extending slit. The vertically extending slit may be aligned with the rows of first and second nozzles, so that main parts of the first and second vapor plumes can propagate through the slit. An edge of a first wall element may provide a first shaper wall edge on a first side of the slit, and an edge of a second wall element may provide a second shaper wall edge on a second side of the slit, so that vapor plumes emitted by the first and second vapor distribution pipes can be laterally limited by the first and / or by the second shaper wall edges.

[0080] The shaper wall 212 may be provided between the first and second distribution pipes and the substrate plane (SP), particularly extending essentially parallel to the substrate plane (SP). The shaper wall is typically not fixed at or mounted at the first and second vapor distribution pipes. The shaper wall 212 may be arranged closer to the substrate plane (SP) than to the first and second vapor distribution pipes.

[0081] In some embodiments, the shaper wall 212 has a first shaper wall edge configured to laterally limit the first vapor plumes on a side opposite the second vapor distribution pipe 120 (i.e. , on a first “outer” side of the overlapping vapor plumes) and / or the shaper wall 212 has a second shaper wall edge configured to laterally limit the second vapor plumes on a side opposite the first vapor distribution pipe 110 (i.e., on a second “outer” side of the overlapping vapor plumes).

[0082] In some embodiments, the plume shaper arrangement 210 includes both the first vapor plume shaper 211 , which is connected to the first and / or second vapor distribution pipe and is arranged close to the nozzles, and the shaper wall 212 that is arranged separately from the first and second vapor distribution pipes. The first vapor plume shaper 211 may be configured to limit the first and / or second vapor plumes on an “inner” side of the overlapping vapor plumes (i.e., at a position partially between thefirst and second vapor plumes), and the shaper wall 212 may be configured to limit the first and / or second vapor plumes on one or two “outer” sides of the overlapping vapor plumes, as it is schematically depicted in FIG. 3.

[0083] In some embodiments, the first material and / or the second material is a metal. In particular, the first material is silver and / or the second material is magnesium. Typically, a cathode layer may be deposited by the first and second vapor distribution pipes on the substrate 10 that is moved past the evaporation source 100, wherein the cathode layer may be a mixed metal layer that comprises two metals, particularly silver and magnesium. A silver layer reaching far below the overhang 12 to contact the sidewall 11 below the overhang 12 is particularly beneficial, because silver has a good conductivity and can ensure a reliable cathode contact.

[0084] In some embodiments, which can be combined with other embodiments described herein, the first vapor distribution pipe and the second vapor distribution pipe are fixedly and non-rotatably mounted in the vacuum chamber. In particular, the evaporation source is a non-rotatable evaporation source, so that the first nozzle axis M1 of the first nozzle and the nozzle axis M2 of the second nozzle constantly and continuously point in the same direction. A non-rotatable evaporation source is less complex, less prone to failure, and may require less maintenance than an evaporation source that includes an actuator for enabling a source rotation.

[0085] In particular, in at least some embodiments, the evaporation source is fixedly mounted in the vacuum chamber so as to be not rotatable around an axis, and to be not displaceable in a translation direction.

[0086] In some implementations, the evaporation source 100 is a metal evaporation source that is configured to deposit a mixed metal layer comprising the first and second materials being two metals by co-deposition, particularly a mixed-metal cathode layer of an OLED layer stack.

[0087] In some embodiments the first nozzles 111 of the row of first nozzles are arranged in a first nozzle plane that is parallel to the substrate plane (SP), and the second nozzles 121 of the row of second nozzles are arranged in a second nozzle plane that is parallel to the substrate plane, the first nozzle plane being closer to (oralternatively further from) the substrate plane than the second nozzle plane. In the exemplary embodiments of FIG. 3, the first nozzles 111 are arranged in a first nozzle plane that is closer to the substrate plane than the second nozzle plane, in which the second nozzles 121 are arranged. The distance between the first nozzle plane and the second nozzle plane may be 3 cm or more, or even 5 cm or more. Arranging the first nozzles closer to (or further from) the substrate plane (SP) than the second nozzles may be beneficial, because a larger relative angle between the first nozzle axis M1 and the second nozzle axis M2 can be provided, improving an overlap between the first and second vapor plumes in the substrate plane while enabling the first vapor plumes to be overall tilted.

[0088] FIG. 4 shows a schematic sectional view of another evaporation source 100 according to embodiments described herein in a horizontal sectional plane. The evaporation source of FIG. 4 essentially corresponds to the evaporation source of FIG. 3, so that reference can be made to the above explanations, which are not repeated here. The evaporation source of FIG. 3 includes a third vapor distribution pipe 130 that is configured to deposit a further layer on the substrate in succession to the mixed material layer, e.g., below or above the mixed material layer.

[0089] The evaporation source 100 of FIG. 4 is configured to coat a substrate 10 that is arranged in the substrate plane (SP), in particular, a substrate 10 that is moved past the evaporation source 100 in the substrate plane (SP) along the substrate transport path T. The evaporation source 100 includes a first vapor distribution pipe 110 with a row of first nozzles 111 configured to direct first vapor plumes of a first material onto the substrate 10, a second vapor distribution pipe 120 with a row of second nozzles 121 configured to direct second vapor plumes of the second material onto the substrate 10, and (at least) a third vapor distribution pipe 130 with a row of third nozzles 131 configured to direct third vapor plumes of a third material onto the substrate. The first nozzles 111 each have a first nozzle channel 112 that respectively defines a first nozzle axis M1, the second nozzles 121 each have a second nozzle channel 122 that respectively defines a second nozzle axis M2, and the third nozzles 131 each have a third nozzle channel that respectively defines a third nozzle axis M3.

[0090] As already explained with respect to FIG. 3, the row of first nozzles 111 andthe row of second nozzles 121 are configured to deposit a mixed material layer that includes the first and second materials onto the substrate that is moved past the evaporation source.

[0091] The row of third nozzles 131 is configured to deposit a further layer comprising the third material above or below the mixed material layer onto the substrate. In particular, the row of third nozzles 131 is configured such that the further layer and the mixed material layer can be deposited on the substrate in succession as separate layers.

[0092] For example, the evaporation source comprises a metal source that is configured to deposit a further layer, e.g., a first layer (which is not necessarily a metal), with the third vapor distribution pipe 130 and to co-deposit the mixed material layer that is a mixed metal layer on top of the further layer with the first and second vapor distribution pipes, when the substrate is moved past the evaporation source 100. The further layer may be an electron injection layer (EIL) or an electron transport payer (ETL) of an OLED layer stack, and the mixed metal layer may be a cathode layer of the OLED layer stack.

[0093] In some embodiments, the plume shaper arrangement 210 is configured to improve or ensure an overlap between the first vapor plumes and the second vapor plumes in the substrate plane, and / or the plume shaper arrangement 210 is configured to prevent or reduce an overlap between the first (+ second) vapor plumes and the third vapor plumes in the substrate plane. In other words, in the substrate plane, the third vapor plumes impinge on a third area that does not substantially overlap with the first and second areas where the first and second vapor plumes impinge.

[0094] In some embodiments, which can be combined with other embodiments described herein, the third nozzles 131 are tilted toward the first and second nozzles so that the third vapor plumes cross through the first vapor plumes and through the second vapor plumes upstream of the substrate plane to enable a successive deposition of the mixed material layer and the further layer above or below one another on the substrate. A setup that enables the third vapor plumes to completely cross through the first and second vapor plumes is schematically depicted in FIG. 4. As can be seen in FIG. 4, the third area that is covered by the third vapor plumes on thesubstrate does not overlap with the first and second areas that are covered by the first and second vapor plumes on the substrate. Therefore, the third vapor plumes can fully propagate through the first and second vapor plumes and impinge on the substrate at a position after they have exited the first and second vapor plumes to provide two separate deposition layers on top of each other.

[0095] The plume shaper arrangement 210 may be configured as already explained with respect to FIG. 3. The plume shaper arrangement 210 may be further configured to laterally limit the third vapor plumes emitted by the third nozzles 131 to reduce or avoid an overlap between a first area in the substrate plane covered by the first vapor plumes and a third area in the substrate plane covered by the third vapor plumes, and / or to reduce or avoid an overlap between a second area in the substrate plane covered by the second vapor plumes and the third area in the substrate plane covered by the third vapor plumes.

[0096] In some embodiments, the first, second and third vapor plumes are directed through one common slit of a shaper wall 212 that is arranged between the vapor distribution pipes and the substrate plane, wherein the shaper wall 212 may be configured to limit laterally outer portions of the first, second and / or third vapor plumes. Alternatively or additionally, a first vapor plume shaper may be connected to at least one of the vapor distribution pipes and may be configured to individually limit one or both lateral edges of the first, second, and / or third vapor plumes, respectively. The combination of the shaper wall 212 with the first vapor plume shaper can provide a good overlap between the areas covered by the first and second vapor plumes in the substrate plane, while ensuring that the third vapor plumes impinge on a different area of the substrate spaced apart from the first and second vapor plumes.

[0097] The mixed material layer may be a cathode layer of an OLED layer stack, and the further layer may be an electron injection layer or an electron transport layer deposited below the cathode layer.

[0098] In some embodiments, the first material is silver and / or the second material is magnesium. Optionally the third material emitted by the row of third nozzles is ytterbium or LiF (lithium fluoride), which materials can be used in, e.g., an electron injection layer. Accordingly, a mixed silver + magnesium layer can be deposited abovean ytterbium layer or above an Li F layer.

[0099] As is schematically depicted in FIG. 4, the third vapor distribution pipe 130 may be arranged next to the first vapor distribution pipe 110 and / or next to the second vapor distribution pipe 120 in the same vacuum chamber, for example on a common source body (not shown in FIG. 4).

[0100] Typically, the first, second and third vapor distribution pipes are non-rotatably mounted in the vacuum chamber, e.g., on a common source body that is not rotatable.

[0101] According to another aspect described herein, a method of coating a substrate in a vacuum chamber with a mixed material layer is provided. The substrate is coated using an evaporation source as described herein, the evaporation source having a first vapor distribution pipe and at least a second vapor distribution pipe that are configured to co-deposit a mixed material layer on the substrate.

[0102] FIG. 5 is a flow diagram that schematically illustrates a deposition method described herein. The method can be carried out by any of the evaporation sources described herein, particularly by any of the vacuum deposition systems as described herein.

[0103] As is shown by box 510, first vapor plumes of a first material are directed onto the substrate with a row of first nozzles of the first vapor distribution pipe, and second vapor plumes of a second material are directed onto the substrate with a row of second nozzles of the second vapor distribution pipe. The first nozzles respectively have a first nozzle channel defining a first nozzle axis M1 that is tilted relative to a perpendicular (SN) to the substrate plane, and the second nozzles respectively have a second nozzle channel defining a second nozzle axis M2.

[0104] As is shown by box 520, the substrate is moved past the evaporation source to deposit the mixed material layer comprising the first material and the second material on the substrate.

[0105] At least the first vapor plumes emitted by the first nozzles are laterally limited and shaped with a plume shaper arrangement so that the first material impacts on thesubstrate on only one side of an orthogonal plane that is perpendicular to the substrate plane and intersects the row of first nozzles. Specifically, the first vapor plumes emitted by the first nozzles may be shaped such that none of the vapor trajectories hit the substrate perpendicularly, but rather all the vapor trajectories are tilted in a direction pointing below an overhang. For example, all vapor particles of the first material impinging on the substrate may have an angle >0° relative to a perpendicular to the substrate plane.

[0106] The first tilt angle a of the first nozzle axis relative to the perpendicular (SN) to the substrate plane may be 30° or more, particularly 45° or more. The first vapor plumes may be limited on one or both sides by a plume shaper arrangement to provide, in a respective sectional plane (X) defined by the first nozzle axis M1 and the perpendicular (SN), a maximum impingement angle amaxof the first vapor plumes of 50° or more and 85° or less, and / or a minimum impingement angle aminof the first vapor plumes of more than 0° and less than 30° relative to the perpendicular (SN).

[0107] In some embodiments, the first nozzles of the first vapor distribution pipe and the second nozzles of the second vapor distribution pipe are tilted toward each other to co-deposit the mixed material layer on the substrate with a good overlap.

[0108] In some embodiments, the substrate has a structure formed thereon comprising a sidewall 11 adjacent to a pixel region 13 and an overhang 12 projecting from the sidewall 11 , wherein the first nozzle axis M1 is tilted by the first tilt angle a to increase an amount of the first material deposited below the overhang, particularly such that the deposited first material contacts the sidewall below the overhang. The amount of the first material deposited below the overhang in relation to amount of the first material deposited on uncovered regions of the substrate can be increased by (1) the first tilt angle of the first nozzles pointing into a region below the overhang, in combination with (2) the overall tilt of each of the vapor trajectories of the first vapor plumes toward one side of the perpendicular (SN), particularly such that the first material impacts on the substrate on only one side of an orthogonal plane that is perpendicular to the substrate plane and intersects the row of first nozzles.

[0109] In some embodiments, the plume shaper arrangement laterally limits the first vapor plumes and optionally the second vapor plumes so that an overlap ratiobetween a first area covered by the first vapor plumes and a second area covered by the second vapor plumes in the substrate plane is 80% or more, particularly 90% or more. In particular, the first area covered by the first vapor plumes in the substrate plane and the second area covered by the second vapor plumes in the substrate area may substantially (>90%) or completely overlap.

[0110] In some embodiments, in box 510, third vapor plumes of a third material are additionally directed onto the substrate with a row of third nozzles of a third vapor distribution pipe of the evaporation source. The third vapor distribution pipe may be arranged adjacent to at least one of the first and second vapor distribution pipes, the third nozzles respectively having a third nozzle channel defining a third nozzle axis M3. The third nozzles deposit a further layer comprising the third material above or below the mixed material layer onto the substrate.

[0111] In some embodiments, the third nozzles are tilted relative to the first and second nozzles to deposit the further layer below or above the mixed material layer. For example, the third nozzles may be tilted away from the first and second nozzles to provide a third area spaced apart from the first and second areas in the substrate plane. In the latter embodiment, the third vapor plumes do not cross through the first and second vapor plumes, but are rather pointing in another direction onto another area of the substrate in the substrate transport direction. Alternatively, the third nozzles are tilted toward the first and second nozzles so that the third vapor plumes completely cross through the first and second vapor plumes before the third vapor plumes impinge on the substrate, as it is schematically depicted in FIG. 4.

[0112] In some embodiments, a first layer is deposited on the substrate with the third vapor distribution pipe, and a mixed metal layer is co-deposited on the substrate with the first and second vapor distribution pipes above the first layer during the movement of the substrate past the evaporation source.

[0113] The first layer may be an electron injection layer, particularly an ytterbium layer or LiF layer, and / or the mixed metal layer may be a cathode layer of an OLED layer stack, particularly comprising co-deposited silver and magnesium. The first material that is strongly directed toward an area below the overhang as described herein may be silver, because silver is a good conductor that can provide a reliablemetal contact.

[0114] In some embodiments, the first and second vapor distribution pipes (and the optional third vapor distribution pipe) are fixedly mounted in the vacuum chamber of the vapor deposition system so that the directions of the first nozzle axis M1 and of the second nozzle axis M2 (and of the optional third nozzle axis M3) remain continuously constant before, during, and after the material deposition on the substrate. In alternative embodiments, the evaporation source may be rotatable, for example between a deposition position and an idle position.

[0115] In optional box 530, the substrate having the mixed material layer deposited thereon may be transported along the substrate transport path T into another vacuum chamber, for example for being coated with another layer or for being unloaded from the vacuum deposition system.

[0116] An OLED display device manufactured according to any of the methods described herein and / or using any of the deposition systems or evaporation sources described herein is shown in FIG. 6. The OLED display device includes a layer stack with a plurality of layers, including a mixed material layer manufactured as described herein. The layer stack may be an OLED layer stack as described above with reference to FIG. 6.

[0117] The substrate 10 of the OLED display device has a structure formed thereon comprising a sidewall 11 adjacent to a pixel region 13 and an overhang 12 projecting from the sidewall. The mixed material layer may be a cathode layer 711 of an OLED layer stack that includes two co-deposited metals, the cathode layer 711 reaching below the overhang 12 to contact the sidewall 11 at a position below the overhang. In particular, the cathode layer may include co-deposited silver and magnesium.

[0118] In some embodiments, an electron injection layer 712 may be deposited below the cathode layer 711, e.g. an ytterbium layer or LiF layer.

[0119] In some embodiments, the thickness of the cathode layer 711 at a position contacting the sidewall 11 below the overhang 12 may be at least 30% of the thickness of the cathode layer 711 on a region of the substrate that is not covered by theoverhang, particularly at least 40%, more particularly at least 50%, or even 60%. A reliable cathode contact between the cathode layer 711 and the sidewall 11 and / or the assistant cathode 716 can be ensured.

[0120] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

[0121] In particular, this written description uses examples, including the best mode, and also to enable any person skilled in the art to practice the described subject-matter, including making and using any devices or systems and performing any incorporated methods. While various specific embodiments have been disclosed in the foregoing, mutually non-exclusive features of the embodiments described above may be combined with each other.

Claims

CLAIMS1. An evaporation source (100) for depositing a mixed material layer on a substrate (10) arranged in a substrate plane in a vacuum chamber, comprising:a first vapor distribution pipe (110) with a row of first nozzles (111) configured to direct first vapor plumes of a first material onto the substrate, the first nozzles (111) respectively having a first nozzle channel (112) defining a first nozzle axis (M1 ) that is tilted relative to a perpendicular (SN) to the substrate plane by a first tilt angle (a) of 30° or more;a plume shaper arrangement (210) configured to laterally limit the first vapor plumes emitted by the first nozzles (111) to provide, in a respective sectional plane (X) defined by the first nozzle axis (M1) and the perpendicular (SN), a maximum impingement angle (amax) of the first vapor plumes of 50° or more and 85° or less and a minimum impingement angle (amin) of the first vapor plumes of more than 0° and less than 30° relative to the perpendicular (SN); anda second vapor distribution pipe (120) with a row of second nozzles (121) configured to direct second vapor plumes of a second material onto the substrate, the second nozzles respectively having a second nozzle channel defining a second nozzle axis (M2),wherein the row of first nozzles (111) and the row of second nozzles (121 ) are configured to deposit a mixed material layer comprising the first and second materials onto a substrate that is moved relative to the evaporation source.

2. An evaporation source for depositing a mixed material layer on a substrate (10) arranged in a substrate plane in a vacuum chamber, comprisinga first vapor distribution pipe (110) with a row of first nozzles (111) configured to direct first vapor plumes of a first material onto the substrate, the first nozzles respectively having a first nozzle channel defining a first nozzle axis (M1 ) that is tilted relative to a perpendicular (SN) to the substrate plane by a first tilt angle (a);a second vapor distribution pipe (120) with a row of second nozzles (121) configured to direct second vapor plumes of a second material onto the substrate, the second nozzles respectively having a second nozzle channel defining a second nozzle axis (M2); anda plume shaper arrangement (210) configured to laterally limit at least the first vapor plumes emitted by the first nozzles (111 ) so thatthe first material impacts on the substrate on only one side of an orthogonal plane that is perpendicular to the substrate plane (SP) and intersects the row of first nozzles (111), anda mixed material layer comprising the first and second materials is deposited onto a substrate that is moved relative to the evaporation source.

3. The evaporation source of claim 1 or 2, wherein the first nozzle channel (112) of the first nozzles (111) respectively has a cross-sectional area of at least 0.5 mm2.

4. The evaporation source of any of claims 1 to 3, wherein one or more of the following applies:the first nozzle axis (M1) of the first nozzles is respectively tilted relative to the perpendicular (SN) to the substrate plane by the first tilt angle (a) of 45° or more and 70° or less, particularly 50° or more and 55° or less;the plume shaper arrangement (210) limits the first vapor plumes on a first lateral side to provide, in a respective sectional plane (X) defined by the first nozzle axis (M1) and the perpendicular (SN), a maximum impingement angle (amax) of the first vapor plumes of 60° or more and 80° or less; andthe plume shaper arrangement (210) limits the first vapor plumes on a second lateral side to provide, in the respective sectional plane (X), the minimum impingement angle (amin) of 5° or more and 25° or less.

5. The evaporation source of any of claims 1 to 4, wherein the plume shaper arrangement (210) is further configured to laterally limit the second vapor plumes emitted by the second nozzles (121) to provide a partial or essentially full overlapbetween a first area in the substrate plane covered by the first vapor plumes and a second area in the substrate plane covered by the second vapor plumes.

6. The evaporation source of any of claims 1 to 5, wherein the plume shaper arrangement (210) comprises one or both of:a first vapor plume shaper (211) connected to at least one of the first and second vapor distribution pipes and having at least a first shaping edge (213) for laterally limiting the first vapor plumes and a second shaping edge (214) for laterally limiting the second vapor plumes; anda shaper wall (212) arranged separately from the first and second vapor distribution pipes and having at least a first shaper wall edge and a second shaper wall edge for laterally limiting at least one of the first vapor plumes and the second vapor plumes.

7. The evaporation source of claim 6, wherein the plume shaper arrangement (210) comprises:the first vapor plume shaper (211) having the first shaping edge (213) configured to laterally limit the first vapor plumes on a side adjacent to the second vapor distribution pipe (120) and the second shaping edge (214) configured to laterally limit the second vapor plumes on a side adjacent to the first vapor distribution pipe (110); andthe shaper wall (212) having at least one of the first shaper wall edge configured to laterally limit the first vapor plumes on a side opposite the second vapor distribution pipe (120) and the second shaper wall edge configured to laterally limit the second vapor plumes on a side opposite the first vapor distribution pipe (110).

8. The evaporation source of any of claims 1 to 7, further comprising:a third vapor distribution pipe (130) with a row of third nozzles (131) configured to direct third vapor plumes of a third material onto the substrate, the third nozzles respectively having a third nozzle channel defining a third nozzle axis (M3), whereinthe row of third nozzles (131) is configured to deposit a further layer comprising the third material above or below the mixed material layer onto the substrate.

9. The evaporation source of claim 8, wherein the third nozzles (131) are tilted toward the first nozzles (111) and the second nozzles (121) so that the third vapor plumes cross through the first vapor plumes and through the second vapor plumes upstream of the substrate plane to enable a successive deposition of the mixed material layer and the further layer above or below one another on the substrate.

10. The evaporation source of claim 8 or 9, wherein the plume shaper arrangement (210) is further configured to laterally limit the third vapor plumes emitted by the third nozzles (131) to avoid an overlap between a first area in the substrate plane covered by the first vapor plumes and a third area in the substrate plane covered by the third vapor plumes.

11. The evaporation source of any of claims 8 to 10, wherein the mixed material layer is a cathode layer of an OLED layer stack, and the further layer is an electron injection layer or an electron transport layer deposited below the cathode layer.

12. The evaporation source of any of claims 1 to 11, wherein the first material is silver and / or the second material is magnesium, and optionally wherein a third material emitted by a row of third nozzles of a third vapor distribution pipe (130) is ytterbium or LiF.

13. The evaporation source of any of claims 1 to 12, wherein the first vapor distribution pipe and the second vapor distribution pipe, and optionally a third vapor distribution pipe, are non-rotatably mounted in the vacuum chamber.

14. The evaporation source of any of claims 1 to 13, wherein the first nozzles are arranged in a first nozzle plane that is parallel to the substrate plane and the second nozzles are arranged in a second nozzle plane that is parallel to the substrate plane, the first nozzle plane being closer to or further from the substrate plane than the second nozzle plane.

15. A vacuum deposition system, comprising:a vacuum chamber;the evaporation source (100) according to any of claims 1 to 14 in the vacuum chamber (1001);a substrate transportation track (1013) configured to move a substrate (10) in the substrate plane along a substrate transport path (T) past the evaporation source (100); andoptionally a shield transportation track (1012) between the substrate transportation track and the evaporation source (100) configured to move a movable shield (1030) in front of the substrate (10) for shielding an edge region of the substrate.

16. A method of coating a substrate in a vacuum chamber with an evaporation source that has a first vapor distribution pipe (110) and at least a second vapor distribution pipe (120), the method comprising:directing first vapor plumes of a first material onto the substrate arranged in a substrate plane with a row of first nozzles of the first vapor distribution pipe (110), the first nozzles respectively having a first nozzle channel (112) defining a first nozzle axis (M1) that is tilted relative to a perpendicular (SN) to the substrate plane by a first tilt angle (a) of 30° or more;laterally limiting the first vapor plumes with a plume shaper arrangement (210) to provide, in a respective sectional plane (X) defined by the first nozzle axis (M1) and the perpendicular (SN), a maximum impingement angle (amax) of the first vapor plumes of 50° or more and 85° or less, and a minimum impingement angle (amin) of the first vapor plumes of more than 0° and less than 30° relative to the perpendicular (SN);directing second vapor plumes of a second material onto the substrate with a row of second nozzles (121) of the second vapor distribution pipe (120), the second nozzles (121) respectively having a second nozzle channel defining a second nozzle axis (M2); andmoving the substrate relative to the evaporation source (100) to deposit a mixed material layer comprising the first material and the second material on the substrate.

17. The method of claim 16, further comprising:directing third vapor plumes of a third material onto the substrate with a row of third nozzles (131) of a third vapor distribution pipe (130) arranged adjacent to at least one of the first and second vapor distribution pipes, the third nozzles (131 ) respectively having a third nozzle channel defining a third nozzle axis (M3), the third nozzles (131) directed such that a further layer comprising the third material is deposited above or below the mixed material layer.

18. The method of claim 16 or 17, wherein a first layer is deposited on the substrate with the third vapor distribution pipe, and a mixed metal layer is co-deposited on the substrate with the first and second vapor distribution pipes above the first layer during a movement of the substrate past the evaporation source (100).

19. The method of any of claims 16 to 18, wherein the substrate has a structure formed thereon comprising a sidewall (11) adjacent to a pixel region (13) and an overhang (12) projecting from the sidewall (11), wherein the first nozzle axis (M1) is tilted relative to the perpendicular (SN) by the first tilt angle to increase an amount of the first material deposited below the overhang.

20. The method of any of claims 16 to 19, wherein the first vapor distribution pipe and the second vapor distribution pipe are fixedly mounted in the vacuum chamber so that directions of the first nozzle axis (M1 ) and of the second nozzle axis (M2) remain constant before, during, and after material deposition.

21. An OLED display device, comprising a substrate coated with a layer stack including a mixed material layer, manufactured in accordance with the method of any of claims 16 to 20 or using the evaporation source of any of claims 1 to 14.

22. The OLED display device of claim 21, wherein the substrate has a structure formed thereon comprising a sidewall (11) adjacent to a pixel region (13) and an overhang (12) projecting from the sidewall (11), wherein the mixed material layer is a cathode layer comprising two co-deposited metals that reaches below the overhang to contact the sidewall.

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