JP7594597B2 - ASSEMBLY FOR MATERIAL EVAPORATION, VACUUM DEPOSITION APPARATUS, AND METHOD FOR MATERIAL EVAPORATION - Patent application - Google Patents

Description

[0001] The present disclosure relates to assemblies and methods for material evaporation, e.g., evaporation of organic materials. Embodiments of the present disclosure relate, in particular, to assemblies and methods for generating a vapor flow, and in particular, to an assembly and method for generating an organic material vapor flow suitable for making organic light emitting diodes (OLEDs) in a vacuum deposition system. In particular, embodiments of the present disclosure relate to assemblies for material evaporation, vacuum deposition apparatus, and methods for material evaporation.

[0002] In many technical fields and applications, it is useful to deposit a layer of material on a substrate. In particular, during the manufacture of organic light emitting diodes (OLEDs), a thin film of one or more materials is formed on a substrate. In particular, the layer of organic material is formed by evaporation. For the evaporation of the material, a crucible can be used to generate a vapor stream. The vapor passes through a mask to form a film on the substrate in a predetermined pattern. Co-deposition of two or more materials, such as a host and a dopant, is also contemplated for the fabrication of OLEDs.

[0003] OLEDs are light-emitting diodes whose light-emitting layer comprises a thin film of certain organic materials. OLEDs are used in display and lighting applications, particularly in television screens, computer monitors, and mobile phones. OLED displays exhibit superior performance compared to conventional LCD displays. In particular, OLED displays offer higher brightness, higher contrast, wider viewing angles, and improved color range. OLEDs are used to display pixels, but because OLEDs emit light directly, no backlighting is required. Thus, in addition to improved performance, OLED displays also consume significantly less energy than conventional LCD displays. OLEDs can also be fabricated on flexible substrates.

[0004] An OLED contains one or more layers of organic material between two electrodes. In an OLED display, layers are therefore deposited onto a substrate using an organic evaporator to form a matrix of individually controllable pixels. In the organic evaporator, the organic material is heated to cause it to evaporate. The vapor is then directed through a mask onto the substrate to form a layer in a predetermined pattern.

[0005] A crucible can be used to evaporate the material to be deposited. The material to be evaporated is placed in the crucible in a solid state, usually as a powder, and heat is supplied to evaporate the material placed in the crucible.

[0006] It can be difficult to accurately guarantee the evaporation rate of the material in the crucible while avoiding degradation of highly unstable organic materials that are prone to degradation upon evaporation.

[0007] It is therefore beneficial to control the heat or heat distribution within the crucible to minimize material degradation. This advantage is particularly relevant to the manufacture of OLEDs and OLED screens and displays.

[0008] In light of the above, an assembly for material evaporation, a vacuum deposition apparatus, and a method for material evaporation are provided. Further details, aspects, advantages, and features are apparent from the dependent claims, detailed description, and accompanying drawings.

[0009] According to one embodiment, an assembly for material evaporation is provided. The assembly for material evaporation includes a crucible configured to contain material for material evaporation, one or more mesh structures disposed within the crucible, and one or more coils configured to provide inductive energy, the inductive energy heating the one or more mesh structures for material evaporation.

[0010] According to one embodiment, a vacuum deposition apparatus is provided. The vacuum deposition apparatus includes an assembly for material evaporation according to any embodiment of the present disclosure.

[0011] According to one embodiment, a method for material evaporation is provided. The method for material evaporation includes providing a material in a crucible such that at least one mesh structure of one or more mesh structures contacts the material, passing a current through one or more coils of the assembly, and evaporating the material by inductive heating.

[0012] In order that the above features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly summarized above will be made by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings show only exemplary embodiments and therefore should not be considered limiting in scope, as other equally effective embodiments may be recognized.

FIG. 1 shows a schematic cross-sectional view of an assembly for material evaporation according to an embodiment of the present disclosure. FIG. 1 shows a schematic cross-sectional view of an assembly for material evaporation according to an embodiment of the present disclosure, including a distribution pipe. 1 shows a schematic cross-sectional view of an assembly for material evaporation according to an embodiment of the present disclosure with an opening near the bottom wall of the crucible. 1 shows a schematic diagram of an evaporation device according to an embodiment of the present disclosure. 1 is a flow chart illustrating an embodiment for material evaporation according to an embodiment of the present disclosure.

[0018] Reference will now be made in detail to the various embodiments. One or more examples of the embodiments are illustrated in the figures. Each example is provided by way of explanation and not meant to be limiting. For example, features illustrated or described as part of one embodiment can be used on or in combination with any other embodiment to yield yet another embodiment. The present disclosure is intended to include such modifications and variations. Many of the details, dimensions, angles, and other features shown in the figures are merely illustrative of particular implementations. Thus, other implementations can have other details, components, and features without departing from the spirit or scope of the present disclosure. Moreover, further implementations of the present disclosure can be practiced without some of the details described below.

[0019] In the following description of the drawings, the same reference numbers indicate the same or similar components. Generally, only the differences with respect to the individual embodiments are described. Unless otherwise specified, the description of a part or aspect in one embodiment may also apply to the corresponding part or aspect in other embodiments.

[0020] The assemblies and methods described herein are particularly configured for material evaporation in organic evaporators such as those used in the manufacture of OLEDs and OLED displays, screens and monitors.

[0021] In embodiments of the present disclosure, steam is generated by induction in a crucible, particularly a ceramic crucible. The crucible includes one or more mesh structures. For example, one or more electrical conductors may be provided within the crucible to transfer induced heat to the one or more mesh structures. In some embodiments, the electrical conductors may be rings, particularly metal rings, disposed adjacent to an inner wall of the crucible.

[0022] According to some embodiments, which may be combined with other embodiments described herein, an assembly for material evaporation is provided. The assembly includes a crucible configured to contain material for material evaporation and one or more mesh structures disposed within the crucible. One or more coils are configured to provide inductive energy, which heats the one or more mesh structures for material evaporation. For example, the one or more coils may indirectly heat the one or more mesh structures by heating one or more electrical conductors. Additionally or alternatively, the one or more coils may directly heat the one or more mesh structures, for example, by generating an induced current in the mesh structure.

[0023] FIG. 1 shows a schematic cross-sectional view of an assembly for material evaporation according to an embodiment of the present disclosure. The assembly for material evaporation 100 includes a crucible 110, one or more mesh structures 130 disposed within the crucible, and one or more coils 140. Current flowing through the coils of the one or more coils 140 heats at least one mesh of the one or more meshes. The coils of the one or more coils 140 are configured to provide inductive heating that is transferred to at least one mesh of the one or more meshes 130 within the crucible 110. In some embodiments, three or more coils can be provided, each coil configured to provide heating to a corresponding mesh structure of the one or more mesh structures. For example, six or more coils can be provided.

[0024] According to some embodiments, three mesh structures may be provided along the filling height of the crucible. Depending on the amount of material provided in the crucible, the mesh structures of the plurality of mesh structures may be switched on or off. In particular, the more material is provided to the crucible, the less amount of mesh structures that are heated. Thus, the heat load on the material provided to the crucible may be reduced, while at the same time, clogging of the evaporated material by the mesh structures may be avoided.

[0025] As exemplarily shown in FIG. 1, one or more electrical conductors 120 are located within the crucible 110. Current flowing through one or more of the one or more coils 140 induces current within one or more of the one or more conductors 120. Thus, the one or more conductors are heated by induction heating. Induction heating is transferred from the one or more conductors to respective mesh structures of one or more mesh structures 130 disposed within the crucible 110.

[0026] In some embodiments, the crucible is at least partially filled with material, particularly with organic material for the manufacture of OLEDs, e.g., or OLED displays or screens. The material can be a powder that passes through the meshes of one or more mesh structures 130 to at least partially fill the volume in the crucible 110 or the volume between the mesh structures, or the volume between the mesh structures and the walls of the crucible. To heat, the powder can contact the mesh structures of one or more mesh structures 130.

[0027] When current flows through at least one of the one or more coils 140, at least one of the one or more electrical conductors 120 in the crucible is heated by electromagnetic induction, i.e., by inductive heating. In some embodiments, heat is further transferred from the at least one electrical conductor to at least one of the mesh structures 130. When heat is transferred from the at least one electrical conductor to the at least one mesh structure, the mesh structure heats up, and heat is further transferred to the powder in contact with or embedded in the mesh structure, causing the powder to vaporize.

[0028] For example, it is advantageous to provide one or more conductors in the form of a ring. Thus, one or more conductors can surround the mesh structure so that it is indirectly heated by the one or more conductors. Additionally or alternatively, one or more conductors 120 can be located near one or more inner walls of the crucible. Alternatively, the one or more conductors can be located at different positions in the crucible, as long as they are suitable for being heated by induction. One or more conductors, in particular one or more metal rings, are heated by induction and the heat is transferred to the adjacent mesh structure. The material for material evaporation in contact with the mesh is heated while the wall of the crucible is at a lower temperature than the material being evaporated. Thus, the heat load on the organic material can be reduced, especially compared to a crucible in which heat is provided from the wall of the crucible.

[0029] In some embodiments, the crucible includes walls, e.g., a top wall, a bottom wall, and a side wall. As shown in FIG. 2, an opening 210 is provided in the wall, e.g., in the top wall in FIGS. 1 and 2 and in the bottom wall in FIG. 3. A coil is wound around the outer side of the crucible. In some embodiments, material can be transferred into the crucible through a fill opening in the crucible wall. The fill opening may be sealable, e.g., with a suitable seal or plug.

[0030] In some embodiments, there are one or more coils, e.g., three coils, that can be operated separately, i.e., current can be passed through each coil separately. For example, the coils can be cooled, e.g., by water cooling, such as active water cooling. In some embodiments, water or a cooling fluid can flow within the hollow wires of one or more coils 140 to better cool one or more coils 140. Additionally or alternatively, a cooling fluid can be provided between the wires or conductors of one or more coils. The fluid can be a gas or a liquid.

[0031] FIG. 5 shows a flow chart of a method 600 for material evaporation. Considering the crucible shown in FIG. 1, which may be filled up to the upper mesh structure inside the crucible, i.e., the upper mesh structure in FIG. 1, only the top coil may be activated (indicated by box 610). The surface of the organic material, e.g., the top surface of a quantity of powder filled in the crucible, is heated by the top mesh, which is heated by the top coil. The remaining coils are not activated. Thus, the remaining mesh is not actively heated, and material degradation can be avoided or reduced. During further operation of the evaporator, the organic material is consumed and, in the exemplary embodiment shown in FIG. 1, the filling level of the organic material in the crucible decreases. The filling level may decrease to be lower than the top mesh structure. Accordingly, further mesh structures below the previously activated mesh structure may be additionally heated by the activation of further separate coils (indicated by box 620). Over time, the middle coil and finally the bottom coil are added to the process, vaporizing all of the material in the crucible.

[0032] Because only the material to be evaporated needs to be at evaporation temperature, it is advantageous to operate the coils from top to bottom, i.e., operate only the top coil at first, and over time add the middle coils and finally the bottom coil. The remaining material can remain at a lower temperature. Furthermore, upon subsequent operation of the lower coils, e.g., subsequent heating of the lower mesh (see box 620), the upper coils remain active to avoid clogging of the upper mesh structure for the lower fill level.

[0033] One particular advantage associated with the present disclosure is, for example, avoidance or reduction of material degradation during the evaporation process. Also, the thermal load of the evaporation material is reduced and a larger surface area is available for evaporation. In other embodiments, there may be a different number of coils and current is passed sequentially through adjacent coils along a top-to-bottom direction. Active cooling may be used to dissipate heat generated in the coils due to power consumption, etc.

[0034] As shown in FIG. 2, an opening 210 can be provided in or near the top wall of the crucible through which vapor of the evaporated material flows, for example, through distribution tube 200 and through opening 202 onto the substrate to be coated. According to some embodiments, which can be combined with other embodiments described herein, one or more electrical conductors 120 are coupled to one or more mesh structures 130 for transferring heat, for example, by conduction, to the one or more mesh structures. As discussed above, each electrical conductor may be coupled to a corresponding mesh structure. Alternatively, each electrical conductor may be coupled to a corresponding set of mesh structures, for example, two or more mesh structures disposed within the crucible.

[0036] The material to be evaporated, e.g., powder, can be placed in the crucible 110. For example, the powder can be introduced, e.g., through an opening 210 in or near the top wall of the crucible 110, or through a sealable opening. The distribution tube may be removable and temporarily disassembled to allow the introduction of material to the crucible, e.g., to allow the introduction of powder. The material introduced into the crucible 110 can cover the mesh structure in the crucible. In FIG. 2, three coils 140 are exemplarily shown. According to the method 600 for material evaporation as shown in FIG. 5, a current is applied to the top coil shown in FIG. 2 according to box 610, thus heating the top mesh structure closest to the opening 210. Thus, the material in contact with the top mesh structure is evaporated. Once all of the material in contact with the top mesh structure has been completely vaporized, current is also passed through the middle coil of the three coils 140 shown in FIG. 2 in accordance with box 620 to vaporize the material on the middle mesh structure of the mesh structures 130 shown in FIG. 2. Finally, once the material in contact with the middle mesh structure has also been completely vaporized, current is also passed through the bottom coil of the three coils 140 in accordance with box 620 in FIG. 5 to heat the bottom mesh structure of the three mesh structures 130 shown in FIG. 2.

[0037] During evaporation, the vapor passes through openings 210 in or near the top wall of the crucible 110, flows through the distribution tube 200, and finally exits in a uniform flow through openings 202 of the distribution tube 200 to coat a substrate in a vacuum deposition apparatus according to an embodiment of the present disclosure.

[0038] In some embodiments, good thermal contact is provided between the mesh structure and the rings (e.g., metal rings) that form electrical conductors. The one or more mesh structures exhibit good thermal conductivity. In some embodiments, the one or more mesh structures include a ceramic material. For example, the one or more mesh structures can include or consist of AlN or Shapal, i.e., a combination of AlN and BN, e.g., 70% aluminum nitride and 30% boron nitride. The one or more mesh structures may include silicon carbide.

[0039] According to the embodiments described herein, the organic material can be contained in a crucible with a similar low temperature. This prevents degradation of the material. The organic material is heated for a short time and vaporizes, e.g., only the material close to the mesh structure is heated. Thus, an exemplary embodiment that can be combined with other embodiments described herein has a crucible with a similar low thermal conductivity. The crucible may include a ceramic material. The crucible may include SiC, but ceramics may be used that provide a lower thermal conductivity for the crucible than silicon carbide. Thus, the heat introduced into the assembly of the crucible and one or more mesh structures can reduce the temperature rise in other areas of the crucible, e.g., areas that are not currently heated. According to some embodiments, the crucible may include or be made of ZrO2, AlO2, or PBN (pyrolytic boron nitride).

[0040] In some embodiments, the current through each coil of the one or more coils 140 can be individually controlled to individually control the inductive heating of one or more electrical conductors coupled to the coils. The current through each coil of the one or more coils 140 can be individually controlled to individually control the heating of one or more mesh structures.

[0041] In some embodiments, the assembly 100 for material evaporation includes a bottom wall, a top wall, a side wall, an opening in or near the top wall, and one or more coils are disposed around the side wall of the crucible.

[0042] In some embodiments, the bottom and top walls of the assembly for material evaporation are positioned parallel to the ground surface, with the top wall at a higher distance/height from the ground surface than the bottom wall of the assembly. In some embodiments, vapor generated in the crucible flows vertically through openings 210 in or near the top wall.

[0043] The one or more coils 140 may also be actively cooled. For example, water may flow around the one or more coils in the space between the crucible wall and the outermost wall of the material evaporation assembly. Further, in addition, or instead, the coil may include hollow windings or conductors. Making the windings or conductors hollow allows for cooling within the coil windings or conductors.

[0044] In some embodiments, the assembly for material evaporation includes a bottom wall, a top wall, a side wall, an opening 310 in or near the bottom wall, and one or more coils are disposed around the side walls of the crucible. Vapor of evaporated material flows through the opening 310 in or near the bottom wall, thus traveling in the opposite direction compared to other embodiments in which the vapor flows through an opening in the top wall.

[0045] In some embodiments, the powder of the material to be evaporated cannot pass through the mesh of the one or more mesh structures, and therefore the powder cannot embed the one or more mesh structures. In those embodiments, the powder is supported by the one or more mesh structures. As exemplarily shown in FIG. 3, the powder can be placed on the mesh structure of the one or more mesh structures, for example through an additional opening, for example through a sealable opening, for example in a side wall, and cannot pass through the mesh of the one or more mesh structures. In some embodiments, when an electric current is applied to at least one coil of the one or more coils, the material, for example powder, on the mesh structure of the one or more mesh structures is heated and evaporation occurs. The vapor can spread through the mesh of the mesh structure, in the space below the mesh structure, toward the bottom of the crucible.

[0046] In some embodiments, the one or more mesh structures can be a mesh structure 130, as exemplarily and diagrammatically shown in FIG. 3. The one or more coils can be a coil 150. The crucible can be filled, for example, from the top, for example, from an opening in the top or through a removable or closable portion of the top wall. A powder of the material to be evaporated is supported, for example, on the mesh structure. According to the method 600 for material evaporation shown in FIG. 5, according to box 610, the coil 140 shown in FIG. 3 provides induction heating to heat the mesh structure, and the material is evaporated. Vapor of the evaporated material flows through the mesh of the mesh structure 130 shown in FIG. 3 toward the bottom of the crucible, where the vapor finally passes through an opening 310 in or near the bottom wall of the crucible 110. In FIG. 3, the assembly 100 for material evaporation is further connected to a distribution tube 300 having one or more openings 302 configured to distribute the vapor that has passed through an opening 310 in or near the bottom wall of the crucible towards the substrate to be coated. According to some embodiments, which can be combined with other embodiments described herein, the one or more mesh structures can be a single mesh structure in contact with the powder. However, additional mesh structures can also be provided. For example, the additional mesh structure can be in contact with the evaporated material in a liquid state and/or can avoid tripping of the material in a liquid state below the single mesh structure in contact with the powder. According to some examples, the additional mesh structure can improve two-stage evaporation, i.e., from a solid state to a liquid state and from a liquid state to a gaseous state. Additionally or alternatively, dripping of the material below the single mesh structure in contact with the powder or dropping of the material through the single mesh structure can be reduced or avoided. Additionally, additional mesh structures can be included to increase the energy supplied to the powder.

[0047] According to some embodiments, which may be combined with other embodiments described herein, the assembly for material evaporation may be configured to prevent direct contact between the powder of the material to be evaporated and one or more conductors to avoid overheating of the material. For example, the crucible may include a shield disposed around the one or more conductors to prevent direct contact between the powder of the material to be evaporated and one or more conductors to avoid overheating of the material. For example, the shield may be disposed such that the one or more conductors are disposed between the shield and a wall of the crucible. The reduced contact between the organic material and the one or more conductors may further inhibit degradation of the organic material.

[0048] A method for material evaporation can include providing a material in the crucible 110 such that at least one of the one or more mesh structures 130 is in contact with the material, applying current to one or more coils 140 of the assembly, and evaporating the material by inductive heating. For example, current is applied sequentially to each coil of the one or more coils 140. According to FIG. 5, a method 600 for material evaporation is provided in which current is applied to the top coil, as shown in box 610, to activate the top mesh structure associated with the top coil, i.e., to heat the top mesh structure, and then, in a repeating manner, additional mesh structures below the previously activated mesh structure are additionally and sequentially activated, i.e., heated (as shown in box 620), until all mesh structures have been activated or evaporation or coating of the substrate is completed.

[0049] First, current is applied only to the coils closest to the top wall of the crucible, and then to the coils adjacent to the coils already having current applied thereto. Then, current is applied sequentially to additional coils, e.g., sequentially to coils adjacent to the coils already having current applied thereto that have not yet had current applied thereto. In some embodiments, the application of current to the coils proceeds from top to bottom, e.g., from the top wall to the bottom wall, e.g., from the coils closest to the top wall to the coils closest to the bottom wall of the crucible. Once current is applied to the coils, current remains applied to the coils until all coils have current applied thereto and/or until the evaporation process is complete. In some embodiments, the sequential application of current ensures uniform evaporation of the material from the surface of the material and avoids degradation of the material due to excessive temperatures within the material being evaporated.

[0050] The unevaporated material, in particular the powder of the unevaporated material, fills the interior of the crucible to a predetermined height, i.e. to a predetermined fill level/fill height, which is variable over time during the evaporation process. The boundary between the unevaporated material and the vapor during the material evaporation forms a surface, and the fill level at which the unevaporated material fills the crucible can be defined, for example, as the distance of said surface from the bottom wall of the crucible. In some embodiments, the current is applied to the coils at a level/height relative to the bottom of the crucible that is at or near the actual fill level at which the crucible is filled with unevaporated material, e.g., near the fill level at which the crucible is filled with powder of the unevaporated material. Applying current to each coil in sequence has the effect of heating all mesh structures close to or above the fill level at which the unevaporated material (e.g., powder) fills the crucible.

[0051] According to an embodiment of the present disclosure, heating, particularly induction heating, is provided to keep the material to be evaporated located near the boundary between the unevaporated material in the crucible and the vapor at an optimal temperature while avoiding internal degradation of the material to be evaporated due to overheating. Thus, a beneficial heat distribution is provided, particularly to avoid material degradation. The heat load of the material to be evaporated can be reduced. A larger surface area is available for evaporation.

[0052] FIG. 4 illustrates a deposition apparatus according to an embodiment described herein. The deposition apparatus 400 may be configured to deposit evaporated material on a substrate 410. The deposition apparatus 400 includes a deposition chamber 470, particularly a vacuum deposition chamber. In the embodiment of the deposition apparatus 400 as shown in FIG. 4, the deposition apparatus 400 includes an assembly 100 for material evaporation according to any of the embodiments described herein in a deposition chamber (particularly a vacuum deposition chamber) and a distribution assembly 420 for depositing the evaporated deposition material. The distribution assembly 420 includes at least one distribution tube. In some embodiments, the distribution assembly 420 may include a rotatable distribution tube configured to be rotatable about an axis of the distribution tube. In some embodiments, the distribution assembly 420 may include multiple distribution tubes. In some embodiments, the distribution assembly 420 includes the distribution tube 200 illustrated in FIG. 2, i.e., a distribution tube disposed above the assembly 100 for material evaporation. In other embodiments, the distribution assembly 420 includes the distribution pipe 300 illustrated in FIG. 3, i.e., a distribution pipe configured to receive vapor flowing through an opening in or near the bottom wall of the crucible 110 of the assembly 100 for material evaporation. In some embodiments, the distribution assembly 420 may further include a heating unit. In some embodiments, the distribution assembly 420 may further include a cooling unit.

[0053] The embodiments described herein relate in particular to the deposition of organic materials, such as for OLED display manufacturing, on large area substrates. According to some embodiments, the large area substrate or a carrier supporting one or more substrates can have a size of 0.5 ^m2 or more, in particular 1 ^m2 or more. For example, the deposition apparatus 400 can be adapted to process large area substrates such as GEN5, which corresponds to about 1.4 ^m2 substrate (1.1 m x 1.3 m), GEN7.5, which corresponds to about 4.29 ^m2 substrate (1.95 m x 2.2 m), GEN8.5, which corresponds to about 5.7 ^m2 substrate (2.2 m x 2.5 m), or even GEN10, which corresponds to about 8.7 ^m2 substrate (2.85 m x 3.05 m). Larger generations such as GEN11 and GEN12 and the corresponding substrate areas are feasible as well. For example, in the manufacture of OLED displays, half sizes of the substrate generations listed above, including GEN 6, can be coated by evaporation. The half size of a substrate generation may be the result of some processes being performed on a full size substrate and subsequent processes being performed on half of the previously processed substrate.

[0054] According to embodiments herein that may be combined with other embodiments described herein, the thickness of the substrate may be between 0.1 mm and 1.8 mm, and the holding device for the substrate may be adapted to such a substrate thickness. The thickness of the substrate may be about 0.9 mm or less, such as 0.5 mm or 0.3 mm, and the holding device may be adapted to such a substrate thickness. Typically, the substrate 410 may be made of a material suitable for material deposition. For example, the substrate may be made of a material selected from the group consisting of glass (e.g., soda-lime glass, borosilicate glass, etc.), metal, polymer, ceramic, composite material, carbon fiber material, or other material or combination of materials that can be coated by a deposition process.

[0055] According to embodiments described herein, material can be deposited in a pattern on the substrate, for example, by using a mask 463, such as a fine metal mask (FMM) having a plurality of openings. A plurality of pixels can be deposited on the substrate.

[0056] According to some embodiments, which may be combined with any other embodiment described herein, the deposition chamber 470 may be a vacuum deposition chamber. In the present disclosure, a "vacuum deposition chamber" may be understood as a chamber configured for vacuum deposition. The term "vacuum" as used herein may be understood in the sense of a technical vacuum, for example having a vacuum pressure below 10 mbar. Typically, the pressure in a vacuum chamber described herein may be between ^10-5 mbar and about ^10-8 mbar, more typically between ^10-5 mbar and ^10-7 mbar, and even more typically between about ^10-6 mbar and about ^10-7 mbar.

[0057] According to some embodiments, the pressure in the vacuum chamber can be considered to be either the partial pressure of the evaporated material in the vacuum chamber or the total pressure (which can be approximately the same if the evaporated material is the only component present in the vacuum chamber to be deposited). In some embodiments, the total pressure in the vacuum chamber can range from about ^10-4 mbar to about ^10-7 mbar, especially if a second component other than the evaporated material is present in the vacuum chamber (such as a gas).

[0058] As exemplarily shown in FIG. 4, the material evaporation assembly 100 and the distribution assembly 420 can be provided on a track or linear guide 464. The linear guide 464 may be configured for translational movement of the material evaporation assembly 100 and the distribution assembly 420. Further, there may be a drive device for providing translational movement of the material evaporation assembly and the distribution assembly. In particular, a conveying device for contactlessly conveying the material evaporation assembly may be provided in the vacuum deposition chamber.

[0059] As exemplarily shown in FIG. 4, the deposition chamber 470 may have a gate valve 465, through which the vacuum deposition chamber can be connected to an adjacent routing module or an adjacent service module. Typically, the routing module is configured to transport the substrate to a further vacuum deposition apparatus for further processing, and the service module is configured for maintenance within the deposition chamber. In particular, the gate valve allows a vacuum seal to an adjacent vacuum chamber, such as an adjacent routing module or an adjacent service module, and can be opened or closed to transfer the substrate and/or mask into or out of the vacuum deposition apparatus.

[0060] According to an embodiment, which may be combined with any other embodiment described herein, a substrate may be processed in the deposition apparatus 400. In particular, two substrates, e.g. a first substrate and a second substrate, may be supported on respective transport tracks in the deposition chamber 470. Furthermore, two tracks for providing a mask 463 thereon may also be provided. In particular, the tracks for transporting the substrate carrier and/or the mask carrier may be provided with further transport devices for contactless transport of the carrier.

[0061] Typically, depositing material on the substrate 410 may include masking the substrate with a respective mask 463, e.g., with an edge exclusion mask or with a shadow mask. According to some embodiments, the masks 463, e.g., a first mask corresponding to the first substrate and a second mask corresponding to the second substrate, are provided in a mask frame for holding the respective masks in place.

[0062] As shown in FIG. 4, the linear guide 464 provides a direction of translation of the assembly for material evaporation and the dispensing assembly 420. On both sides of the assembly 100, masks 463 can be provided, e.g., a first mask for masking the first substrate and a second mask for masking the second substrate. The masks can extend essentially parallel to the direction of translation of the assembly for material evaporation. Furthermore, the substrates on opposite sides of the deposition source can also extend essentially parallel to the direction of translation.

[0063] With exemplary reference to FIG. 4, an assembly support 461 may be provided that is configured for translational movement of the material evaporation assembly 100 and the distribution assembly 420 along a linear guide 464. Typically, as shown in FIG. 4, the assembly support 461 supports the material evaporation assembly 100 and the distribution assembly 420 disposed above the crucible. Thus, the evaporated material generated in the material evaporation assembly can move upward and exit from one or more openings of at least one distribution tube of the distribution assembly. Thus, as described herein, the distribution assembly is configured to provide a plume of evaporated material, in particular evaporated organic material, from the distribution assembly 220 to the substrate 10. In an embodiment in which the distribution tube is rotatable, a single distribution tube can be rotated to distribute vapors of evaporated material toward substrates 410 disposed on opposite sides of the distribution assembly 420. In such an embodiment, the dispense assembly 420 can be translated parallel to the substrate 410 and can be rotated to dispense the vapor of the evaporated material first toward a first substrate and then toward a second substrate. The rotation and translation can be repeated multiple times during the coating of one or more substrates.

5 shows a flow diagram of a method 600 for material evaporation using an assembly for material evaporation according to an embodiment described herein. Box 610 includes actuating a mesh structure, e.g., a top mesh structure, by passing a current through the coil and providing a temperature gradient in the crucible 110 using inductive heating provided by at least one coil 140. One or more electrical conductors 120 may be inductively heated by the coil and transfer heat to one or more mesh structures 130. Additionally or alternatively, one or more mesh structures 130 may be directly heated by induction by one or more coils. The crucible, one or more coils, one or more mesh structures and/or one or more electrical conductors may be provided according to an embodiment of the present disclosure.

[0065] According to an embodiment, a crucible can provide material to be deposited on a substrate. The material can be placed in the crucible 110 and evaporated on one or more mesh structures 130 within the crucible. The one or more mesh structures can be heated by induction heating to an evaporation temperature T _E of the material to be deposited. The heating can provide a temperature gradient that includes a temperature range below the evaporation temperature T _E of the material to be deposited. This allows for storage and evaporation of the material in parallel.

[0066] According to box 620, a further mesh structure is activated by passing a current through the coil to heat it, the mesh structure being adjacent to the already activated mesh structure. Box 620 can include sequentially heating the further mesh structure located below and adjacent to the previously heated mesh structure, in particular the further mesh structure being the topmost mesh structure in the crucible that is covered by or in contact with the material to be evaporated. The mesh structures can be activated in sequence, e.g. the topmost mesh structure being activated first by passing a current through a coil, e.g. the topmost coil, according to box 610, and the further mesh structures being activated sequentially according to box 620. Thus, induction heating of the mesh structures starts with the topmost mesh structure, and the remaining mesh structures are heated sequentially from top to bottom.

[0067] According to an embodiment, a material supply system may supply new material to the crucible for evaporation of material at one or more mesh structures. The material supply system may be configured to store material while simultaneously supplying material to the crucible (e.g., via additional openings in the crucible wall). Additionally, the material supply system allows for easy refilling without interrupting the supply and/or deposition process.

[0068] This document uses examples to disclose the disclosure including the best mode and 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 methods incorporated therein. Although various specific embodiments have been disclosed above, the mutually non-exclusive features of the above-described embodiments may be combined with each other. The patentable scope is defined by the claims.

Claims (17)

An assembly (100) for material evaporation, comprising:
a crucible (110) configured to contain material as a powder for material evaporation at least partially filling a volume within the crucible ;
a plurality of mesh structures (130) and a plurality of electrical conductors (120) within the crucible, wherein each electrical conductor of the plurality of electrical conductors (120) is coupled to a corresponding mesh structure of one of the plurality of mesh structures (130) for transferring heat to at least one mesh structure of the plurality of mesh structures (130) , and at least one of the plurality of mesh structures is configured to contact the material ; and a plurality of coils (140), wherein each coil of the plurality of coils is configured to provide inductive energy to a corresponding electrical conductor of at least one of the plurality of electrical conductors, the inductive energy heating the corresponding electrical conductor of at least one of the plurality of electrical conductors, and the heat being transferred to the corresponding mesh structure of at least one of the plurality of mesh structures that is coupled to the corresponding electrical conductor of the plurality of electrical conductors and in contact with the material for material evaporation .
An assembly (100) for material evaporation comprising: The assembly of claim 1, wherein the plurality of conductors are rings. The assembly of claim 2, wherein the ring is disposed adjacent to an inner wall of the crucible. The assembly of any one of claims 1 to 3, configured to sequentially heat at least one mesh structure of the plurality of mesh structures for material evaporation by heating a further mesh structure of the plurality of mesh structures that is disposed adjacently below a previously heated mesh structure of the plurality of mesh structures. The assembly according to any one of claims 1 to 3, wherein the crucible is a ceramic crucible. The assembly of any one of claims 1 to 3, wherein the plurality of mesh structures comprises a ceramic material. The assembly of claim 6, wherein the plurality of mesh structures comprises silicon carbide. An assembly according to any one of claims 1 to 3, wherein the flow of current through the multiple coils is individually controllable for each coil. The assembly of any one of claims 1 to 3, wherein the coils are water-cooled. 4. An assembly according to claim 1, further comprising: a cooling fluid supply between the wires or conductors of the coils . The crucible comprises:
Bottom wall,
Top wall,
Sidewall,
an opening in or near the top wall;
4. The assembly of claim 1 , wherein the plurality of coils are disposed about the side wall of the crucible. The assembly of claim 11, further comprising a distribution tube in communication with the opening in or near the top wall configured for distribution of evaporated material. The crucible comprises:
Bottom wall,
Top wall,
Sidewall,
an opening in or near the bottom wall;
4. The assembly of claim 1 , wherein the plurality of coils are disposed about the side wall of the crucible. The crucible comprises:
Bottom wall,
Top wall,
Sidewall,
an opening in or near the bottom wall;
5. The assembly of claim 4, wherein the plurality of coils are disposed about the side wall of the crucible. A vacuum deposition apparatus (400) comprising an assembly (100) for material evaporation according to any one of claims 1 to 3. 1. A method (600) for material evaporation, comprising:
providing a material as a powder in the crucible such that at least one mesh structure of a plurality of mesh structures is in contact with the material to at least partially fill a volume within the crucible , wherein a plurality of electrical conductors are provided in the crucible , each electrical conductor of the plurality of electrical conductors being coupled to a corresponding mesh structure of the plurality of mesh structures for transferring heat to the at least one mesh structure of the plurality of mesh structures;
Passing a current through at least one coil of the assembly (610, 620);
providing inductive energy from the at least one coil of the plurality of coils to at least one corresponding conductor of the plurality of electrical conductors to heat the at least one corresponding conductor of the plurality of electrical conductors; and evaporating the material by heat transfer to at least one corresponding mesh structure of the plurality of mesh structures coupled to the corresponding conductor of the plurality of electrical conductors.
The method includes: The method of claim 16, wherein the current is passed through each coil of the plurality of coils sequentially.

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