WO2016202388A1

WO2016202388A1 - Measurement assembly for measuring a deposition rate and method therefore

Info

Publication number: WO2016202388A1
Application number: PCT/EP2015/063637
Authority: WO
Inventors: Jose Manuel Dieguez-Campo; Karl-Albert Keim; Stefan Bangert; Heike Landgraf
Original assignee: Applied Materials, Inc.
Priority date: 2015-06-17
Filing date: 2015-06-17
Publication date: 2016-12-22
Also published as: KR102082193B1; CN107810410A; JP6640879B2; TW201710535A; KR20180014084A; JP2018519423A

Abstract

A measurement assembly (100) for measuring a deposition rate of an evaporated material is described. The measurement assembly (100) includes an oscillation crystal (110) for measuring the deposition rate, and a holder (120) for holding the oscillation crystal (110), wherein the holder comprises a material having a thermal conductivity k above k=30 W/(m K).

Description

MEASUREMENT ASSEMBLY FOR MEASURING A DEPOSITION RATE AND

METHOD THEREFORE

TECHNICAL FIELD

[0001] The present disclosure relates to a measurement assembly for measuring a deposition rate of an evaporated material, an evaporation source for evaporation of material, a deposition apparatus for applying material to a substrate and a method for measuring a deposition rate of an evaporated material. The present disclosure particularly relates to a measurement assembly for measuring a deposition rate of an evaporated organic material and a method therefore. Further, the present disclosure particularly relates to devices including organic materials therein, e.g. an evaporation source and a deposition apparatus for organic material.

BACKGROUND

[0002] Organic evaporators are a tool for the production of organic light-emitting diodes (OLED). OLEDs are a special type of light-emitting diode in which the emissive layer comprises a thin-film of certain organic compounds. 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. The range of colors, brightness, and viewing angle possible with OLED displays is greater than that of traditional LCD displays because OLED pixels directly emit light and do not involve a back light. Therefore, the energy consumption of OLED displays is considerably less than that of traditional LCD displays. Further, the fact that OLEDs can be manufactured onto flexible substrates results in further applications.

[0003] The functionality of an OLED depends on the coating thickness of the organic material. This thickness has to be within a predetermined range. In the production of OLEDs, the deposition rate at which the coating with organic material is effected is controlled to lie within a predetermined tolerance range. In other words, the deposition rate of an organic evaporator has to be controlled thoroughly in the production process.

[0004] Accordingly, for OLED applications but also for other evaporation processes, a high accuracy of the deposition rate over a comparably long time is needed. There is a plurality of measurement systems for measuring the deposition rate of evaporators available. However, these measurement systems suffer from either insufficient accuracy and/or insufficient stability over the desired time period.

[0005] Accordingly, there is a continuing demand for providing improved deposition rate measurement systems, deposition rate measurement methods, evaporators and deposition apparatuses.

SUMMARY

[0006] In view of the above, a measurement assembly for measuring a deposition rate of an evaporated material, an evaporation source, a deposition apparatus and a method for measuring a deposition rate of an evaporated material according to the independent claims are provided. Further advantages, features, aspects and details are apparent from the dependent claims, the description and drawings.

[0007] According to one aspect of the present disclosure, a measurement assembly for measuring a deposition rate of an evaporated material is provided. The measurement assembly includes an oscillation crystal for measuring the deposition rate, and a holder for holding the oscillation crystal, wherein the holder includes a material having a thermal conductivity k above k=30 W/(mK).

[0008] According to another aspect of the present disclosure, an evaporation source for evaporation of material is provided. The evaporation source includes an evaporation crucible, wherein the evaporation crucible is configured to evaporate a material; a distribution pipe with one or more outlets provided along the length of the distribution pipe for providing evaporated material, wherein the distribution pipe is in fluid communication with the evaporation crucible; and a measurement assembly according to any embodiment described herein.

[0009] According to a further aspect of the present disclosure, a deposition apparatus for applying material to a substrate in a vacuum chamber at a deposition rate is provided. The deposition apparatus includes at least one evaporation source according to embodiments described herein. [0010] According to yet another aspect of the present disclosure, a method for measuring a deposition rate of an evaporated material is provided. The method includes evaporating a material; applying a first portion of the evaporated material to a substrate; diverting a second portion of the evaporated material to an oscillation crystal; and measuring the deposition rate by using the measurement assembly according to embodiments described herein.

[0011] The disclosure is also directed to an apparatus for carrying out the disclosed methods including apparatus parts for performing the methods. The method 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, the disclosure is also directed to operating methods of the described apparatus. It includes a method for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] So that the manner in which the above recited features of the disclosure described herein can be understood in detail, a more particular description, 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:

FIG. 1 shows a schematic top view of a measurement assembly for measuring a deposition rate of an evaporated material according to embodiments described herein;

FIGS. 2A to 2C show schematic side views of a measurement assembly for measuring a deposition rate of an evaporated material according to embodiments described herein;

FIG. 3A shows a schematic view of a measurement assembly in a first state according to embodiments described herein;

FIG. 3B shows a schematic side view of a measurement assembly in a second state according to embodiments described herein;

FIG. 4 shows a schematic side view of a measurement assembly for measuring a deposition rate of an evaporated material according to embodiments described herein; FIGS. 5 A and 5B show schematic side views of an evaporation source according to embodiments described herein;

FIG. 6 shows a perspective view of an evaporation source according to embodiments described herein;

FIG. 7 shows a schematic top view of a deposition apparatus for applying material to a substrate in a vacuum chamber according to embodiments described herein; and

FIG. 8 shows a block diagram illustrating a method for measuring a deposition rate of an evaporated material according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0013] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. In the following, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0014] In the present disclosure, the expression "oscillation crystal for measuring the deposition rate" may be understood as an oscillation crystal for measuring a mass variation of deposited material on the oscillation crystal per unit area by measuring the change in frequency of an oscillation crystal resonator. In particular, in the present disclosure an oscillation crystal may be understood as a quartz crystal resonator. More particularly, an "oscillation crystal for measuring the deposition rate" may be understood as a quartz crystal microbalance (QCM).

[0015] With exemplarily reference to FIG. 1, a measurement assembly 100 for measuring a deposition rate of an evaporated material according to embodiments described herein includes an oscillation crystal 110 for measuring the deposition rate and a holder 120 for holding the oscillation crystal 110. The holder 120 may include a material having a thermal conductivity k above k=30 W/(mK). Particularly, the holder may include a material having a thermal conductivity k above k=50 W/(mK), more particularly above k=70 W/(mK), for example above k=150 W/(mK). Accordingly, thermal effects on the oscillation crystal which can decrease the measurement accuracy may be reduced. In particular, by providing a measurement assembly in which the heat transfer from the oscillation crystal to the holder is enhanced by employing a material having a thermal conductivity k as described herein, negative effects of high temperature on the quality, accuracy and stability of the deposition rate measurement may be reduced or even eliminated. Further, the cooling capability of the measurement assembly, particularly of the oscillation crystal, may be improved compared to conventional oscillation crystal measurement systems. Accordingly, employing a measurement assembly for measuring a deposition rate according to embodiments described herein may be beneficial for high quality display manufacturing, particularly OLED manufacturing.

[0016] According to embodiments which can be combined with other embodiments described herein, the material of the holder 120 includes at least one material selected form the group consisting of: copper, aluminum, copper alloy, aluminum alloy, brass, iron, silver, silver alloy, gold alloy, magnesium, wolfram, silicon carbide, aluminum nitride, or other materials having a thermal conductivity k above k=30 W/(mK), particularly above k=50 W/(mK), more particularly above k=70 W/(mK), for example above k=150 W/(mK). Accordingly, by providing the measurement assembly with a holder including a material as described herein, the heat transfer from the oscillation crystal to the holder can be enhanced such that the quality, accuracy and stability of the deposition rate measurement may be improved. In particular, by providing a holder including a material as described herein for holding the oscillation crystal thermal fluctuations of the oscillation crystal may be reduced or even eliminated. For example, according to embodiments described herein thermal fluctuations of less than 0.50 K (Kelvin), particularly of less than 0.25 K, particularly of less than 0.10 K, more particularly of less than 0.05 K may be achieved.

[0017] According to embodiments which can be combined with other embodiments described herein, the oscillation crystal 110 may be arranged inside the holder 120. As exemplarily shown in FIGS. 2A to 2C a measurement opening 121 may be provided in the holder 120. In particular, the measurement opening 121 may be configured and arranged such that evaporated material may be deposited on the oscillation crystal for measuring the deposition rate of the evaporated material.

[0018] As exemplarily shown in FIG. 2A, according to embodiments which can be combined with other embodiments described herein, the measurement assembly 100 may include a heat exchanger 132. In particular, the heat exchanger 132 may be arranged in the holder 120, for example next to or adjacent to the oscillation crystal 110. Alternatively, the heat exchanger may be arranged on an outer surface of the holder. The heat exchanger 132 may be configured to exchange heat with the oscillation crystal and/or with the holder 120. For example, the heat exchanger may include tubes through which a cooling fluid may be provided. The cooling fluid may be a liquid, e.g. water, or a gas, e.g. air. In particular the cooling fluid may be chilled compressed air. According to embodiments which can be combined with other embodiments described herein the heat exchanger 132 may be configured for cooling the holder 120 and/or the oscillation crystal 110 to a temperature of 15°C or below, particularly 10°C or below (e.g. 8°C), more particularly 5°C or below. Accordingly, by providing the measurement assembly with a heat exchanger as described herein, negative effects of high temperature on the quality, accuracy and stability of the deposition rate measurement may be reduced or even eliminated. In particular, by providing a measurement assembly with a heat exchanger as described herein, thermal fluctuations of the oscillation crystal may be reduced or even eliminated, which may be beneficial for the deposition rate measurement accuracy.

[0019] With exemplarily reference to FIG. 2B, according to embodiments which can be combined with other embodiments described herein, the measurement assembly 100 may include a temperature sensor 131 for measuring the temperature of the oscillation crystal 110. Additionally or alternatively, the temperature sensor may be arranged and configured for measuring the temperature of the holder 120. By providing the measurement assembly with a temperature sensor as described herein, information about the temperature of the measurement assembly may be obtained such that a critical temperature at which the oscillation crystal tends to measure inaccurately may be detected. Accordingly, in the case that a critical temperature of the measurement assembly, particularly of the holder and/or of the oscillation crystal, is detected by the temperature sensor an adequate reaction may be initiated, for example cooling by employing the heat exchanger as described herein, which may be beneficial for the deposition rate measurement accuracy.

[0020] Additionally or alternatively, the temperature sensor 131 may be configured to detect thermal fluctuations of the oscillation crystal 110 and/or the holder 120. In particular, the temperature sensor 131 may be configured to detect thermal fluctuations of less than 0.50 K (Kelvin), particularly of less than 0.25 K, particularly of less than 0.10 K, more particularly of less than 0.05 K. Accordingly, the temperature sensor 131 may detect critical thermal fluctuations of the oscillation crystal 110 and/or the holder 120. In particular, critical thermal fluctuations at which the oscillation crystal tends to measure inaccurately may be detected by the temperature sensor 131. Accordingly, in the case that critical thermal fluctuations, particularly of the holder and/or of the oscillation crystal, are detected by the temperature sensor an adequate reaction may be initiated, for example cooling by employing the heat exchanger as described herein, which may be beneficial for the deposition rate measurement accuracy.

[0021] According to embodiments which can be combined with other embodiments described herein, the measurement assembly 100 may include a temperature control system 130 for controlling the temperature of the oscillation crystal 110 and/or the temperature of the holder 120. In particular, the temperature control system 130 may include one or more of a temperature sensor 131, a heat exchanger 132 and a controller 133. As exemplarily shown in FIG. 2C, the controller 133 may be connected to the temperature sensor 131 for receiving data measured by the temperature sensor 131. Further, the controller 133 may be connected to the heat exchanger 132 for controlling the temperature of the holder 120 and/or the oscillation crystal 110. Accordingly, the controller may be configured for controlling the temperature of the holder 120 and/or oscillation crystal 110 dependent on the temperature measured by the temperature sensor 131. For example, in the case that the temperature sensor 131 detects a critical temperature at which the oscillation crystal tends to measure inaccurately, the controller may initiate a control signal to the heat exchanger 132 for cooling the holder 120 and/or the oscillation crystal 110. Accordingly, in the case that an ideal measurement temperature of the oscillation crystal, for example below 15°C, particularly below 10°C, more particularly below 5°C is detected by the temperature sensor 131, a previously initiated cooling may be stopped by sending a corresponding control signal to the heat exchanger such that the cooling may be stopped. By providing the measurement assembly with a temperature control system as described herein, negative effects of high temperature on the quality, accuracy and stability of the deposition rate measurement may be reduced or even eliminated.

[0022] According to embodiments which can be combined with other embodiments described herein, the measurement assembly 100 may include a shutter 140 for blocking the evaporated material provided from a measurement outlet 150 for providing evaporated material to the oscillation crystal 110, as exemplarily shown in FIGS. 3 A and 3B. In particular, the shutter 140 may be configured to be movable, i.e. a movable shutter, for example linearly movable, from a first state (FIG. 3A) of the shutter into a second state (FIG. 3B) of the shutter. Alternatively the shutter may be configured to be pivotable from a first state into a second state. For example, the first state of the shutter may be an open state in which the shutter 140 does not block the measurement outlet 150 for providing evaporated material to the oscillation crystal 110, as exemplarily shown in FIG. 3 A. Accordingly, the second state of the shutter 140 may be a state in which the shutter 140 blocks the measurement outlet 150 such that the oscillation crystal 110 is protected from evaporated material provided through the measurement outlet 150, as exemplarily shown in FIG. 3B. By providing the measurement assembly with a shutter the measurement assembly, particularly the oscillation crystal and/or the holder may be protected from high temperature of the evaporated material. Accordingly, negative effects of high temperature on the quality, accuracy and stability of the deposition rate measurement may be reduced or even eliminated.

[0023] With exemplary reference to FIG. 4, according to embodiments which can be combined with other embodiments described herein, the shutter 140 may include a thermal protection shield 141 for protecting the oscillation crystal 110 and/or the holder 120 from the heat of the evaporated material provided through the measurement outlet 150. As exemplarily shown in FIG. 4, the thermal protection shield 141 may be arranged on a side of the shutter 140 which faces the measurement outlet 150. In particular, the thermal protection shield 141 may be configured for reflecting heat energy provided by evaporated material provided through the measurement outlet 150. According to embodiments which can be combined with other embodiments described herein, the thermal protection shield 141 may be a plate, for example a sheet metal. Alternatively, the thermal protection shield 141 may include two of more plates, particularly two of more metal sheets, which may be spaced with respect to each other, for example by a gap of 0.1 mm or more. For example the sheet metal may have a thickness of 0.1 mm to 3.0 mm. In particular, the thermal protection shield may include a ferrous or non-ferrous material, for example at least one material selected from the group consisting of copper (Cu), aluminum (Al), copper alloy, aluminum alloy, brass, iron, titanium (Ti), ceramic and other suitable materials.

[0024] Accordingly, a measurement assembly including a thermal protection shield according to embodiments described herein may be beneficial for protecting the oscillation crystal from the temperature, e.g. heat, of the evaporated material, in particular when the shutter is in a closed state. In particular, the oscillation crystal 110 and/or the holder 120 may cool down when the shutter, particularly including a thermal protection shield, is in a closed state. Accordingly, by employing a shutter including a thermal protection shield the cooling rate of the oscillation crystal and/or the holder may be increased which can be beneficial for the performance of the measurement assembly.

[0025] FIGS. 5 A and 5B show schematic side views of an evaporation source 200 according to embodiments as described herein. According to embodiments, the evaporation source 200 includes an evaporation crucible 210, wherein the evaporation crucible is configured to evaporate a material. Further, the evaporation source 200 includes a distribution pipe 220 with one or more outlets 222 provided along the length of the distribution pipe for providing evaporated material, as exemplarily shown in FIG. 5B. According to embodiments, the distribution pipe 220 is in fluid communication with the evaporation crucible 210, for example by a vapor conduit 232, as exemplarily shown in FIG. 5B. The vapor conduit 232 can be provided to the distribution pipe 220 at the central portion of the distribution pipe or at another position between the lower end of the distribution pipe and the upper end of the distribution pipe. Further, the evaporation source 200 according to embodiments described herein includes a measurement assembly 100 according to embodiments described herein. Accordingly, an evaporation source 200 is provided for which the deposition rate can be measured with a high accuracy. Accordingly, employing an evaporation source 200 according to embodiments described herein may be beneficial for high quality display manufacturing, particularly OLED manufacturing. [0026] As exemplarily shown in FIG. 5A, According to embodiments which can be combined with other embodiments described herein, the distribution pipe 220 may be an elongated tube including a heating element 215. The evaporation crucible 210 can be a reservoir for material, e.g. organic material, to be evaporated with a heating unit 225. For example, the heating unit 225 may be provided within the enclosure of the evaporation crucible 210. According to embodiments, which can be combined with other embodiments described herein, the distribution pipe 220 may provide a line source. For example, as exemplarily shown in FIG. 5B, a plurality of outlets 222, such as nozzles, can be arranged along at least one line. According to an alternative embodiment (not shown), one elongated opening, e.g. a slit, extending along the at least one line may be provided. According to some embodiments, which can be combined with other embodiments described herein, the line source may extend essentially vertically.

[0027] According to some embodiments, which can be combined with other embodiments described herein, the length of the distribution pipe 220 may correspond to a height of a substrate onto which material is to be deposited in a deposition apparatus. Alternatively, the length of the distribution pipe 220 may be longer than the height of the substrate onto which material is to be deposited, for example at least by 10% or even 20%. Accordingly, a uniform deposition at the upper end of the substrate and/or the lower end of the substrate can be provided. For example, the length of the distribution pipe 220 can be 1.3 m or above, for example 2.5 m or above.

[0028] According to embodiments, which can be combined with other embodiments described herein, the evaporation crucible 210 may be provided at the lower end of the distribution pipe 220, as exemplarily shown in FIG. 5A. The material, e.g. an organic material, can be evaporated in the evaporation crucible 210. The evaporated material may enter the distribution pipe 220 at the bottom of the distribution pipe and may be guided essentially sideways through the plurality of outlets 222 in the distribution pipe 220, e.g. towards an essentially vertical substrate. With exemplary reference to FIG. 5B, the measurement assembly 100 according to embodiments described herein may be provided at an upper portion, particularly at an upper end, of the distribution pipe 220.

[0029] With exemplarily reference to FIG. 5B, according to embodiments which can be combined with other embodiments described herein, the measurement outlet 150 may be provided in a wall of the distribution pipe 220 or an end portion of the distribution pipe, for example in a wall at the backside 224A of the distribution pipe as exemplarily shown in FIGS. 5B and 6. Alternatively, the measurement outlet 150 may be provided in a top wall 224C of the distribution pipe 220. As exemplarily indicated by the arrow 151 in FIG. 6 the evaporated material may be provided form the inside of the distribution pipe 220 through the measurement outlet 150 to the measurement assembly 100. According to embodiments which can be combined with other embodiments described herein, the measurement outlet 150 may have an opening from 0.5 mm to 4 mm. The measurement outlet 150 may include a nozzle. For example, the nozzle may include an adjustable opening for adjusting the flow of evaporated material provided to the measurement assembly 100. In particular, the nozzle may be configured to provide a measurement flow selected form a range between a lower limit of 1/70 of the total flow provided by the evaporation source, particularly a lower limit of 1/60 of the total flow provided by the evaporation source, more particularly a lower limit of 1/50 of the total flow provided by the evaporation source and an upper limit of 1/40 of the total flow provided by the evaporation source, particularly an upper limit of 1/30 of the total flow provided by the evaporation source, more particularly an upper limit of 1/25 of the total flow provided by the evaporation source. For example, the nozzle may be configured to provide a measurement flow of 1/54 of the total flow provided by the evaporation source.

[0030] FIG. 6 shows a perspective view of an evaporation source 200 according to embodiments described herein. As exemplarily shown in FIG. 6, the distribution pipe 220 may be designed in a triangular shape. A triangular shape of the distribution pipe 220 may be beneficial in case two or more distribution pipes are arranged next to each other. In particular, a triangular shape of the distribution pipe 220 makes it possible to bring the outlets of neighboring distribution pipes as close as possible to each other. This allows for achieving an improved mixture of different materials from different distribution pipes, e.g. for the case of the co-evaporation of two, three or even more different materials. As exemplarily shown in FIG. 6, according to embodiments which can be combined with other embodiments described herein, the measurement assembly 100 may be provided in the hollow space of the distribution pipe 220, particularly at the upper end of the distribution pipe.

[0031] According to embodiments, which can be combined with other embodiments described herein, the distribution pipe 220 may include walls, for example side walls 224B and a wall at the backside 224A of the distribution pipe, e.g. an an end portion of the distribution pipe, which can be heated by a heating element 215. The heating element 215 may be mounted or attached to the walls of the distribution pipe 220. According to some embodiments, which can be combined with other embodiment described herein the evaporation source 200 may include a shield 204. The shield 204 may reduce the heat radiation towards the deposition area. Further, the shield 204 may be cooled by a cooling element 216. For example, the cooling element 216 maybe mounted to the shield 204 and may include a conduit for cooling fluid.

[0032] FIG. 7 shows a schematic top view of a deposition apparatus 300 for applying material to a substrate 333 in a vacuum chamber 310 according to embodiments described herein. According to embodiments which can be combined with other embodiments described herein, the evaporation source 200 as described herein may be provided in the vacuum chamber 310, for example on a track, e.g. a linear guide 320 or a looped track. The track or the linear guide 320 may be configured for a translational movement of the evaporation source 200. Accordingly, according to embodiments which can be combined with other embodiments described herein, a drive for the translational movement can be provided for the evaporation source 200, at the track and/or the linear guide 320, within the vacuum chamber 310. . According to embodiments which can be combined with other embodiments described herein, a first valve 305, for example a gate valve, may be provided which allows for a vacuum seal to an adjacent vacuum chamber (not shown in FIG. 7). The first valve can be opened for transport of the substrate 333 or a mask 332 into the vacuum chamber 310 or out of the vacuum chamber 310.

[0033] According to some embodiments, which can be combined with other embodiments described herein, a further vacuum chamber, such as maintenance vacuum chamber 311 may be provided adjacent to the vacuum chamber 310, as exemplarily shown in FIG. 7. Accordingly, the vacuum chamber 310 and the maintenance vacuum chamber 311 may be connected with a second valve 307. The second valve 307 may be configured for opening and closing a vacuum seal between the vacuum chamber 310 and the maintenance vacuum chamber 311. The evaporation source 200 can be transferred to the maintenance vacuum chamber 311 while the second valve 307 is in an open state. Thereafter, the second valve 307 can be closed to provide a vacuum seal between the vacuum chamber 310 and the maintenance vacuum chamber 311. If the second valve 307 is closed, the maintenance vacuum chamber 311 can be vented and opened for maintenance of the evaporation source 200 without breaking the vacuum in the vacuum chamber 310.

[0034] As exemplarily shown in FIG. 7, two substrates may be supported on respective transportation tracks within the vacuum chamber 310. Further, two tracks for providing masks thereon can be provided. Accordingly, during coating the substrate 333 can be masked by respective masks. For example, the mask may be provided in a mask frame 331 to hold the mask 332 in a predetermined position.

[0035] According to some embodiments, which can be combined with other embodiments described herein, the substrate 333 may be supported by a substrate support 326, which can connect to an alignment unit 312. The alignment unit 312 may adjust the position of the substrate 333 with respect to the mask 332. As exemplarily shown in FIG. 7 the substrate support 326 may be connected to the alignment unit 312. Accordingly, the substrate may be moved relative to the mask 332 in order to provide for a proper alignment between the substrate and the mask during deposition of the material which may be beneficial for high quality display manufacturing. Alternatively or additionally the mask 332 and/or the mask frame 331 holding the mask 332 can be connected to the alignment unit 312. Accordingly, either the mask 332 can be positioned relative to the substrate 333 or the mask 332 and the substrate 333 can both be positioned relative to each other.

[0036] As shown in FIG. 7, the linear guide 320 may provide a direction of the translational movement of the evaporation source 200. On both sides of the evaporation source 200 a mask 332 may be provided. The masks may extend essentially parallel to the direction of the translational movement. Further, the substrates at the opposing sides of the evaporation source 200 can also extend essentially parallel to the direction of the translational movement. As exemplarily shown in FIG. 7 the evaporation source 200 provided in the vacuum chamber 310 of the deposition apparatus 300 may include a support 202 which may be configured for the translational movement along the linear guide 320. For example, the support 202 may support two evaporation crucibles and two distribution pipes 220 provided over the evaporation crucible 210. Accordingly, the vapor generated in the evaporation crucible can move upwardly and out of the one or more outlets of the distribution pipe. [0037] Accordingly, embodiments of the deposition apparatus as described herein provide for improved quality display manufacturing, particularly OLED manufacturing.

[0038] In FIG. 8 a block diagram illustrating a method for measuring a deposition rate of an evaporated material according to embodiments described herein is shown. According to embodiments, the method 400 for measuring a deposition rate of an evaporated material includes evaporating 410 an material, for example an organic material, applying 420 a first portion of the evaporated material to a substrate, diverting 430 a second portion of the evaporated material to an oscillation crystal 110, and measuring 440 the deposition rate by using a measurement assembly 100 according to embodiments described herein. Accordingly, by employing the method for measuring a deposition rate of an evaporated material according to embodiments described herein the deposition rate may be measured highly accurately. In particular, by employing the method for measuring a deposition rate as described herein, thermal effects on the oscillation crystal which can decrease the measurement accuracy may be reduced. Particularly, negative effects of high temperature on the quality, accuracy and stability of the deposition rate measurement may be reduced or even eliminated.

[0039] According to embodiments which can be combined with other embodiments described herein, evaporating 410 material incudes using an evaporation crucible 210 as described herein. Further, applying 420 a first portion of the evaporated material to a substrate may include using an evaporation source 200 according to embodiments described herein. According to embodiments which can be combined with other embodiments described herein, diverting 430 a second portion of the evaporated material to an oscillation crystal 110 may include using a measurement outlet 150, particularly a nozzle, as described herein. In particular diverting 430 a second portion of the evaporated material to the oscillation crystal 110 may include providing a measurement flow selected form a range between a lower limit of 1/70 of the total flow provided by the evaporation source, particularly a lower limit of 1/60 of the total flow provided by the evaporation source, more particularly a lower limit of 1/50 of the total flow provided by the evaporation source and an upper limit of 1/40 of the total flow provided by the evaporation source, particularly an upper limit of 1/30 of the total flow provided by the evaporation source, more particularly an upper limit of 1/25 of the total flow provided by the evaporation source. For example, diverting 430 a second portion of the evaporated material to the oscillation crystal 110 may include providing a measurement flow of 1/54 of the total flow provided by the evaporation source.

[0040] According to embodiments which can be combined with other embodiments described herein, measuring 440 the deposition rate may include exchanging heat with the measurement assembly 100, particularly by a temperature control system 130 as described herein. Accordingly, by exchanging heat with the measurement assembly as described herein, negative effects of high temperature on the quality, accuracy and stability of the deposition rate measurement may be reduced or even eliminated. In particular, by exchanging heat with the measurement assembly as described herein, thermal fluctuations of the oscillation crystal may be reduced or even eliminated, which may be beneficial for the deposition rate measurement accuracy. Accordingly, employing the method for measuring a deposition rate as described herein may be beneficial for high quality display manufacturing, particularly OLED manufacturing.

[0041] Accordingly, the measurement assembly for measuring a deposition rate of an evaporated material, the evaporation source, the deposition apparatus and the method for measuring a deposition rate according to embodiments described herein provide for improved deposition rate measurement and high quality display manufacturing, for example high quality OLED manufacturing.

Claims

1. A measurement assembly (100) for measuring a deposition rate of an evaporated material, comprising:

- an oscillation crystal (110) for measuring the deposition rate, and

- a holder (120) for holding the oscillation crystal (110), wherein the holder comprises a material having a thermal conductivity k above k=30 W/(mK).

2. The measurement assembly (100) according to claim 1, wherein the material of the holder (120) is at least one material selected from the group consisting of: copper, aluminum, copper alloy, aluminum alloy, brass, iron, silver, silver alloy, gold, gold alloy, magnesium, wolfram, silicon carbide and aluminum nitride.

3. The measurement assembly (100) according to claim 1 or 2, further comprising a heat exchanger (132) for exchanging heat with the oscillation crystal (110).

4. The measurement assembly (100) according any of claims 1 to 3, further comprising a temperature sensor (131) for measuring the temperature of the oscillation crystal (110).

5. The measurement assembly (100) according to any of claims 1 to 4, further comprising a temperature control system (130) for controlling the temperature of the oscillation crystal (110), particularly wherein the temperature control system (130) comprises one or more of a temperature sensor (131), a heat exchanger (132) and a controller (133).

6. The measurement assembly (100) according to any of claims 1 to 5, further comprising a shutter (140), particularly a movable shutter, for blocking the evaporated material provided from a measurement outlet (150) for providing evaporated material to the oscillation crystal (110).

7. The measurement assembly (100) according to claim 6, wherein the shutter (140) comprises a thermal protection shield (141) for protecting the oscillation crystal (110) from the temperature of the evaporated material.

8. The measurement assembly (100) according to claims 6 or 7, wherein the shutter (140) comprises at least one cooling element (142), particularly at least one pipe for providing a cooling fluid, for cooling the shutter (140).

9. An evaporation source (200) for evaporation of material, comprising:

- an evaporation crucible (210), wherein the evaporation crucible is configured to evaporate a material;

- a distribution pipe (220) with one or more outlets (222) provided along the length of the distribution pipe for providing evaporated material, wherein the distribution pipe (220) is in fluid communication with the evaporation crucible (210); and

- a measurement assembly (100) according to any of claims 1 to 8.

10. The evaporation source (200) according to claim 9, further comprising a measurement outlet (150) for providing the evaporated material to the oscillation crystal (110) of the measurement assembly (100).

11. The evaporation source (200) according to claim 10, wherein the

measurement outlet (150) is configured for providing a measurement flow from 1/70 of the total flow provided by the evaporation source to 1/25 of the total flow provided by the evaporation source.

12. The evaporation source (200) according to claim 11, wherein the

measurement outlet (150) and the measurement assembly (100) are arranged at an end portion of the distribution pipe (220), particularly at a backside (224A) of the end portion of the distribution pipe (220).

13. A deposition apparatus (300) for applying material to a substrate (333) in a vacuum chamber (310) at a deposition rate, comprising at least one evaporation source (200) according to any of claims 9 to 12.

14. A method (400) for measuring a deposition rate of an evaporated material, comprising:

- evaporating (410) an material;

- applying (420) a first portion of the evaporated material to a substrate;

- diverting (430) a second portion of the evaporated material to an oscillation crystal (110); and

- measuring (440) the deposition rate by using the measurement assembly (100) according to any of claim 1 to 9.

15. The method (400) according to claim 14, wherein measuring (420) the deposition rate comprises exchanging heat with the measurement assembly (100), particularly by a temperature control system (130).