Measurement assembly for measuring a deposition rate of an evaporation source, evaporation source, deposition apparatus, and method of measuring a disposition rate

Abstract

A measurement assembly (100) for measuring a deposition rate of an evaporation source is described. The measurement assembly (100) includes a measurement device (110) for measuring the deposition rate. Additionally, the measurement assembly (100) includes a pipe (120) for providing a passage for evaporated material from a measurement outlet (205) of the evaporation source through a wall (201) of the evaporation source to the measurement device (110). The pipe (120) is connected via a flange (121) of the pipe (120) to a cooling element (210) provided at the wall (201).

Description

MEASUREMENT ASSEMBLY FOR MEASURING A DEPOSITION RATE OF AN EVAPORATION SOURCE, EVAPORATION SOURCE, DEPOSITION APPARATUS, AND METHOD OF MEASURING A DISPOSITION RATETECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to measurement assemblies for measuring a deposition rate of an evaporation source. Further embodiments of the present disclosure relate to evaporation sources and apparatuses for deposition of evaporated material on a substrate. Yet further embodiments relate to methods of measuring a disposition rate of evaporated material. In particular, embodiments described herein relate to display manufacturing, particularly the production of organic light-emitting diodes (OLEDs).BACKGROUND

[0002] Organic evaporators are a tool for the production of organic lightemitting diodes (OLED). OLEDs are a special type of light-emitting diode in which the emissive layer comprises a thin-film of certain organic compounds. 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 angles 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 demand for improved measurement systems, evaporation sources, deposition apparatuses and methods which at least partially overcome one or more of the disadvantages of the state of the art.SUMMARY

[0006] In light of the above, a measurement assembly for measuring a deposition rate of an evaporation source, an evaporation source, a deposition apparatus for depositing evaporated material on a substrate, and a method of measuring a disposition rate of evaporated material according to the independent claims are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0007] According to an aspect of the present disclosure, a measurement assembly for measuring a deposition rate of an evaporation source is provided. The measurement assembly includes a measurement device for measuring the deposition rate. Additionally, the measurement assembly includes a pipefor providing a passage for evaporated material from a measurement outlet of the evaporation source, through a wall of the evaporation source, to the measurement device. The pipe is connected via a flange of the pipe to a cooling element provided at the wall.

[0008] According to another aspect of the present disclosure, an evaporation source for deposition of evaporated material on a substrate is provided. The evaporation source includes an evaporation crucible. Further, the evaporation source includes a distribution assembly with a plurality of outlets for providing evaporated material towards the substrate. Additionally, the evaporation source includes at least one measurement assembly according to any embodiments of the present disclosure.

[0009] According to a further aspect of the present disclosure, a deposition apparatus for depositing evaporated material on a substrate is provided. The deposition apparatus includes a vacuum chamber and at least one deposition source according to any embodiments of the present disclosure.

[0010] According to yet another aspect of the present disclosure, a method of measuring a disposition rate of evaporated material is provided. The method includes providing evaporated material from a measurement outlet of an evaporation source, through a wall of the evaporation source, to a measurement device by using a pipe. Additionally, the method includes providing a cooling of the pipe. Further, the method includes measuring the deposition rate with the measurement device.

[0011] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These 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 according to the disclosure are also directed at methods for operating the described apparatus. The methods for operating the described apparatusinclude method aspects 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 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:FIG. 1 shows a schematic sectional view of a measurement assembly according to embodiments of the present disclosure;FIGS. 2 and 3A show a schematic sectional views of a measurement assembly according to further embodiments of the present disclosure;FIG. 3B shows a schematic front view of a rotatable aperture disk which can be employed in the measurement assembly;FIG. 3C shows a schematic sectional view of a measurement assembly according to embodiments of the present disclosure including a stack of rotatable aperture disks;FIG. 3D shows a schematic sectional view of a stack of rotatable aperture disks according to further embodiments of the present disclosure;FIGS. 4 and 5 show a schematic sectional views of a measurement assembly according to yet further embodiments of the present disclosure;FIG. 6 shows a schematic view of an evaporation source according to embodiments of the present disclosure;FIG. 7 shows a schematic view of a deposition apparatus according to embodiments of the present disclosure; andFIG. 8 shows a block diagram for illustrating a method of measuring a disposition rate of evaporated material, according to embodiments of the present disclosure.DETAILED DESCRIPTION OF EMBODIMENTS

[0013] 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.

[0014] 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 individual embodiments 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.

[0015] With exemplary reference to FIG. 1 , a measurement assembly 100 for measuring a deposition rate of an evaporation source, according to embodiments of the present disclosure is described. According to embodiments, which can be combined with other embodiments described herein, the measurement assembly 100 includes a measurement device 110 for measuring the deposition rate. Additionally, the measurement assembly 100 includes a pipe 120 for providing a passage for evaporated material from a measurement outlet 205 of the evaporation source through a wall 201 of the evaporation source to the measurement device 110. Typically, the wall 201 of the evaporation source through which the pipe 120 is provided is a wall, particularly a backwall, of a casing or housing of the evaporation source. As exemplarily indicated in FIG. 2, typically an opening 202 is providedin the wall 201 through which the pipe 120 extends. The pipe 120 is connected via a flange 121 of the pipe 120 to a cooling element 210 provided at the wall 201. In particular, the cooling element 210 can be attached to, or connected with the wall 201 of the evaporation source. Typically, the flange 121 is fixed to the cooling element 210 by fasteners 129, particularly screws or other removable fasteners, as exemplarily shown in FIG. 2. The pipe 120 may also be referred to as bushing.

[0016] Accordingly, compared to the state of the art, an improved measurement assembly is provided, particularly with respect to measurement stability and accuracy. In particular, the measurement assembly as described herein has the advantage that when evaporated material is provided to the measurement device for measuring the deposition rate, stray coating of surrounding parts can be avoided, while at the same time an improved temperature stability of the measurement device and a lower total heat load to the measurement device can be achieved. Additionally, a fast temperature stabilization of the measurement device, in particular after switching between measurement devices, can be achieved. Further, crosstalk between neighboring measurement assemblies can be eliminated.

[0017] In the present disclosure, a "measurement assembly for measuring a deposition rate of an evaporation source" can be understood as a system configured to quantify the rate at which material from the evaporation source is deposited onto a surface or substrate. In particular, the measurement assembly as described herein can be used in various manufacturing processes, such as thin film deposition and material coating applications, particularly for display manufacturing.

[0018] In the present disclosure, a "measurement device for measuring the deposition rate " can be understood as a device configured for measuring the rate at which the material is being deposited. In particular, the measurement device includes a sensor to monitor and quantify the deposition rate. For instance, the measurement device may include an oscillation crystal formeasuring a mass variation of deposited material on the oscillation crystal per unit area, by measuring the change in frequency of an oscillation crystal resonator. Accordingly, the measurement device for measuring the deposition rate can be a quartz crystal microbalance (QCM).

[0019] In the present disclosure, a "measurement outlet of the evaporation source" may be understood as an opening or aperture, through which evaporated material can be provided to the measurement device. In other words, evaporated material can be emitted from the measurement outlet towards the measurement device. In particular, the measurement outlet may be understood as an opening or aperture which is provided in a wall, particularly a backside wall of a distribution pipe of the evaporation source. More specifically, the measurement outlet can be understood as an opening or aperture, which provides a passage for evaporated material from an interior of the distribution pipe to an exterior of the distribution pipe, particularly a backside of the distribution pipe.

[0020] In the present disclosure, an "evaporation source" can be understood as a source configured to provide evaporated material for deposition on a substrate. In other words, typically the evaporation source is configured to release or emit material in a vaporized form for subsequent deposition onto a substrate.

[0021] In the present disclosure, a "pipe for providing a passage for evaporated material” can be understood as a conduit or channel configured to direct vaporized or evaporated material from the inlet of the pipe to the outlet of the pipe. In other words, the pipe is configured for confining the vaporized or evaporated material.

[0022] In the present disclosure, a "cooling element” can be understood as an element or device configured to dissipate heat in order to lower the temperature. For instance, the cooling element can be a passive coolingelement, particularly a cooling plate, providing a heat sink. Further, the cooling element can be connected to an active cooling, particularly a water cooling.

[0023] With exemplary reference to FIG. 2, typically the pipe 120 has a first pipe opening 126 and a second pipe opening 127. The first pipe opening 126 is directed towards the measurement outlet 205. The second pipe opening 127 is directed towards the measurement device 110. The first pipe opening 126 may also be referred to as a pipe inlet. The second pipe opening 127 may also be referred to as a pipe outlet. In particular, the pipe 120 is a straight pipe extending along a central axis 128. Typically, the inner diameter of the pipe is constant over the length of the pipe 120. As exemplarily indicated in FIG. 2, the first pipe opening 126 and the second pipe opening 127 are provided on opposite ends of the pipe 120. As exemplarily shown in FIG. 4, a pipe outlet aperture 1271 may be provided which reduces effective diameter of the second pipe opening 127, such that the outlet diameter Dout is reduced by the pipe outlet aperture 1271. Providing a pipe outlet aperture can be beneficial for reducing the heat load at the measurement device.

[0024] According to embodiments, which can be combined with other embodiments described herein, the pipe has a first pipe portion 120A and a second pipe portion 120B, as exemplarily shown in FIG. 2. Typically, a first connection plane 120P1is provided between the pipe 120, particularly the flange 121 , and the cooling element 210. In particular, the first connection plane 120P1is the contact plane at the interface between flange 121 and the cooling element 210. As indicated in FIG. 2, the first pipe portion 120A extends from the first connection plane 120P-I to the first pipe opening 126. The second pipe portion 120B extends from the first connection plane 120P1to the second pipe opening 127. Typically, the first pipe portion 120A has a first length L-, and the second pipe portion 120B has a second length L2, as indicated in FIG. 2. Typically, the first length L-, is smaller than the second length L2. In particular, a ratio L-| / L2of the first length to the second length can be L-| / L2< 1 / 1.5, particularly L-| / L2< 1 / 2. Further, the second length L2of the second pipeportion 120B is typically larger than the outer diameter D of the second pipe portion 120B. In particular, the second length L2of the second pipe portion 120B can be L21.5 x D, particularly L2> 2 x D, more particularly L2> 2.5 x D.

[0025] In other words, according to embodiments, which can be combined with other embodiments described herein, the length L-, of the first pipe portion 120A from the first connection plane 120P-, to the first pipe opening 126 directed towards the measurement outlet 205, is smaller than the second length L2of the second pipe portion 120B from the first connection plane 120P-I to the second pipe opening 127, directed towards the measurement device 110. More specifically, the following may apply L2> 1.5 x L-i, particularly L22 X L|.

[0026] With exemplary reference to FIG. 3, the pipe 120 comprises a first pipe part 122 and a second pipe part 123. In particular, the pipe 120 may consist of the first pipe part 122 and the second pipe part 123. In other words, the first pipe part 122 and the second pipe part 123 are two separate parts which can be connected to each other to form the pipe 120. Typically, the first pipe part 122 is of a first material, particularly a first metallic material. The second pipe part 123 can be a second material, particularly a second metallic material, different from the first material. In particular, the second material of the second pipe part 123 can have a higher thermal conductivity than the first material of the first pipe part 122. Typically, the thermal conductivity k of the second material is k > 100 W nr1K’1, particularly k > 150 W nr1K’1. For instance, the second material can be selected from the group consisting of aluminum, aluminum alloy, copper, copper alloy, and aluminum-copper alloy.

[0027] According to embodiments, which can be combined with other embodiments described herein, the first material of the first pipe part 122 has a higher thermostability than the second material of the second pipe part 123. Typically, the first material is thermostable up to a temperature T wherebyT=300°C, particularly T=600°C, more particularly T=900°C. According to an example, the first material is steel, particularly stainless steel.

[0028] With exemplarily reference to Fig. 3, according to embodiments, which can be combined with other embodiments described herein, the first pipe part 122 includes a first flange 124 and the second pipe part 123 includes second flange 125. The first pipe part 122 and the second pipe part 123 are connected via the first flange 124 and the second flange 125, particularly by fasteners 129. Further, as exemplarily shown in FIG. 3, the first flange 124 and the second flange 125 are typically connected together via the fasteners 129 to the cooling element 210. Accordingly, it is to be understood that the first flange 124 and the second flange 125 together may form the flange 121 of the pipe 120, as indicated in FIG. 3.

[0029] Typically, the interface between the first flange 124 and the second flange 125 provide a second connection plane 120P2, as exemplarily shown in FIG. 3. Accordingly, the second connection plane 120P2forms the contact plane between the first pipe part 122 and the second pipe part 123.

[0030] As indicated in FIG. 3, the first pipe part 122 extends from the second connection plane 120P2to the first pipe opening 126. The second pipe part 123 extends from the second connection plane 120P2to the second pipe opening 127. Typically, a length Lp1of the first pipe part 122 is smaller than a length Lp2of the second pipe part 123, as shown in FIG. 3. In particular, a ratio Lp1 / Lp2can be Lp1 / Lp2< 1 / 1.5, particularly Lp1 / Lp2< 1 / 2.

[0031] With exemplarily reference to Fig. 3A, according to embodiments, which can be combined with other embodiments described herein, at least one rotatable aperture disk 140 is provided between the pipe 120, particularly the second pipe opening 127, and the measurement device 110. In particular, it is to be understood that during operation, the at least one rotatable aperture disk 140 is rotated about a central rotation axis 144, particularly of a shaft 143. The at least one rotatable aperture disk 140 can be connected or mechanicallycoupled to the shaft 143. The shaft 143 can be made of a thermally insulating material, such as ceramic or other suitable materials of low thermal conductivity K [W nr1K’1], e.g. materials with a thermal conductivity K < 100 [W nr1K’1], particularly K < 50 [W nr1K’1], more particularly K < 10 [W nr1K’1], or even K < 1 [W nr1K’1].

[0032] In the present disclosure, an “aperture disk” can be understood as a disk having at least one aperture or hole. In particular, the at least one aperture is arranged off the central rotation axis 144. In other words, typically the central rotation axis 144 does not extend through the at least one aperture of the aperture disk. Typically, the aperture disk includes two or more apertures. Preferably, the aperture disk 140 includes a first aperture 141 and a second aperture 142, as exemplarily described with reference to FIGS. 3A and 3B. However, although not explicitly shown, it is to be understood that the aperture disk may include three or more apertures. An aspect ratio AR of the aperture disk, i.e. the ratio of the diameter D of the aperture disk to the thickness T of the aperture disk is typically AR>10, particularly AR>15, more particularly AR >20. The thickness T of the aperture disk 140 is exemplarily indicated in FIG. 3A and the diameter D of the aperture disk 140 is exemplarily indicated in FIG. 3B. Typically, the thickness T of the aperture disk 140 is selected from a range between a lower limit T-i and an upper limit T2, i.e. T-i < T < T2. In particular, the lower limit T-, can be T-, = 0.2 mm, particularly T-, = 0.4 mm, more particularly T-, = 0.8 mm. The upper limit T2can be T2= 1 .5 mm, particularly T2= 2 mm, more particularly T2= 3 mm.

[0033] Typically, the shaft 143 is directly or indirectly connected to a drive 150 as schematically shown in FIG. 3A. From FIG. 3A it can be understood that the drive 150 is configured for providing a rotational motion about the central rotation axis 144. In particular, the drive 150 is configured for rotating the at least one rotatable aperture disk 140 with a rotational speed, such that the frequency of evaporated material provided to the measurementdevice 110 is higher than the detection frequency of the measurement device 110.

[0034] According to embodiments, which can be combined with other embodiments described herein, a frontside 140F and / or a backside 1406 of the at least one rotatable aperture disk 140 as described herein has an emissivity £ < 0.5. Emissivity £ is a measure of a material's ability to emit thermal radiation relative to that of an ideal blackbody at the same temperature. The emissivity £ is a dimensionless quantity and ranges from 0 to 1 . A perfect blackbody, which is an idealized physical body that absorbs all incident electromagnetic radiation and re-emits it perfectly, has an emissivity of 1. Real materials have emissivities less than 1 , meaning they emit less thermal radiation than a blackbody.

[0035] According to embodiments, which can be combined with other embodiments described herein, the frontside 140F and / or the backside 1406 of the at least one rotatable aperture disk 140 can be configured to have an emissivity £ < 0.4, particularly £ < 0.3, more particularly £ < 0.2, or even £ < 0.1 . For example, a low emissivity £ may be obtained by polishing the respective surfaces of the frontside 140F and / or the backside 1406 of the at least one rotatable aperture disk 140. Accordingly, the frontside 140F and / or the backside 1406 of the at least one rotatable aperture disk 140 can include a polished surface having an emissivity £ as described in the present paragraph.

[0036] According to embodiments, which can be combined with other embodiments described herein, a backside 1406 of the at least one rotatable aperture disk 140 as described herein has a lower emissivity £ than a frontside 140F of the at least one rotatable aperture disk 140.

[0037] In the present disclosure, the frontside 140F of the at least one rotatable aperture disk 140 can be understood as the side, particularly the surface, of the at least one rotatable aperture disk 140 which is directed in a direction towards the second pipe opening 127, i.e. the pipe outlet of thepipe 120. Accordingly, the backside 1406 of the at least one rotatable aperture disk 140 can be understood as the side, particularly the surface, of the at least one rotatable aperture disk 140 which is directed in a direction away from the second pipe opening 127, particularly in a direction towards the measurement device 110. It is to be understood that the frontside 140F and the backside 1406 of the at least one rotatable aperture disk are opposite sides.

[0038] FIG. 38 shows a schematic front view of an exemplary rotatable aperture disk 140. Typically, the at least one rotatable aperture disk 140 includes a first aperture 141 and a second aperture 142, which can be point- symmetrical with respect to the rotation axis of the at least one rotatable aperture disk 140. By selecting the size of the first aperture 141 and the second aperture 142, the amount of evaporated material arriving at the measurement device 110 can be controlled. For example, the total size of the first aperture 141 and the second aperture 142 can be selected such that the amount of evaporated material arriving at the measurement device can be reduced by 25% or more, particularly 35% or more, more particularly 50% or more, as compared to the amount of evaporated material introduced into the pipe 120. For better understanding, the second pipe opening 127 with the outlet diameter Dout is indicated by a dotted circle in FIG. 3B. As can be seen from FIG. 3B, the effective cross-sectional flow area of the evaporated material arriving at the measurement device 110 depends on the total size of the first and second apertures 141 , 142. As the total size of the first and second apertures decreases, the blocking area of the at least one rotatable aperture disk 140 increases, such that the amount of evaporated material arriving at the measurement device 110 is reduced.

[0039] It is to be understood that, the rotational speed of the at least one rotatable aperture disk 140 determines the frequency at which evaporated material is provided to the measurement device 110. Typically, the rotational speed of the at least one rotatable aperture disk 140 is selected such that thefrequency of evaporated material provided to the measurement device 110 is higher than the detection frequency of the measurement device 110.

[0040] Further, it is to be understood, that the at least one rotatable aperture disk 140 may also be used as a shutter, particularly when the at least one rotatable aperture disk 140 is stationary and the at least one rotatable aperture disk 140 is positioned such that all material exiting the pipe outlet 127 is blocked by the disk.

[0041] Providing at least one rotatable aperture disk 140 between the pipe 120 and the measurement device 110 as described herein is beneficial for reducing the overall heat load on the measurement device and particularly has a synergistic effect together with the pipe 120 as described herein.

[0042] With exemplary reference to FIGS. 3C and 3D, according to embodiments, which can be combined with other embodiments described herein, the at least one rotatable aperture disk 140 includes a stack 145 of two or more rotatable aperture disks 140 provided between the pipe 120, particularly the second pipe opening 127, and the measurement device 110. A “stack of aperture disks” can be understood in that two or more aperture disks are arranged next to each other. In particular, as shown in FIGS. 3C and 3D, the two or more aperture disks 140 of the stack 145 are arranged spaced from each other and arranged along the central rotation axis 144. Typically, the central rotation axis 144 is a common rotation axis of the two or more aperture disks 140 of the stack 145. FIG. 3C shows an exemplary embodiment with a stack 145 of three aperture disks 140 and FIG. 3D shows an exemplary embodiment with a stack 145 of four aperture disks 140. However, although not explicitly shown, it is to be understood that the stack 145 may include two or five or more aperture disks.

[0043] Typically, a distance d between two neighboring aperture disks 140 of the stack 145 is selected from a range between a lower limit d-i and an upper limit d2, i.e. d-i < d < d2. In particular, the lower limit d-i can be d-i = 0.2 mm,particularly d-i = 0.4 mm, more particularly d-i = 0.8 mm. The upper limit d2can be d2= 1.5 mm, particularly d2= 2 mm, more particularly d2= 3 mm or d2= 5 mm. Preferably, the distance d between two neighboring aperture disks 140 may be constant throughout the stack. However, alternatively the distance d between two neighboring aperture disks 140 can vary throughout the stack 145.

[0044] Typically, the two or more aperture disks 140 of the stack 145 are configured as the at least one rotatable aperture disk 140 as described herein, particularly as described with reference to FIGS. 3A and 3B. The two or more aperture disks 140 of the stack 145 may be configured identically or differently in terms of the features as described for the at least one aperture disk 140. Typically, at least two aperture disks 140 of the stack 145 are configured identically. Preferably, three or more, particularly four or more, of the aperture disks 140 of the stack 145 are configured identically.

[0045] According to embodiments, which can be combined with other embodiments described herein, the apertures of the two or more aperture disks 140 of the stack 145 are arranged such that the apertures at least partially overlap when viewed in direction of the central rotation axis 144. Preferably, the apertures of the two or more aperture disks 140 of the stack 145 are aligned with respect to each other.

[0046] According to embodiments, which can be combined with other embodiments described herein, a rotatable aperture disk as described herein can be connected to the shaft via a pin connector. A “pin connector” can be understood as a mechanical fastener or coupling device used to join the rotatable aperture disk to a shaft. Typically, the pin connector includes two or more pins, which can be inserted into holes or slots of the aperture disk to provide a secure connection to rotate the aperture disk with the shaft.

[0047] With exemplary reference to FIG. 4, according to embodiments, which can be combined with other embodiments described herein, themeasurement outlet 205 includes a nozzle 206 to direct evaporated material into the pipe 120. In particular, the nozzle 206 is arranged and configured to provide evaporated material in the direction of the central axis 128, into the pipe 120. According to an example, the nozzle 206 may at least partially extend into the pipe 120, as exemplarily shown in FIG. 4. It is to be understood, that the amount of evaporated material introduced into the pipe can be controlled by the size of the nozzle.

[0048] According to embodiments, which can be combined with other embodiments described herein, the cooling element 210 may be a cooling plate. It is to be understood, that the cooling element is configured to provide a heat sink. Typically, the cooling element 210 is connected to an active cooling 130, particularly a water cooling, as schematically indicated in FIG. 4.

[0049] With exemplary reference to FIG. 4, according to embodiments, which can be combined with other embodiments described herein, two or more measurement devices, e.g. a first measurement device 111 and a second measurement device 112, coupled to a rotary holder 115 may be provided. The rotary holder 115 is configured to rotate about a rotation axis 116 of the rotary holder, which is typically parallel to the central axis 128 of the pipe. By rotation of the rotary holder 115, the measurement device in front of the second pipe opening 127, i.e. the pipe outlet, may be exchanged. FIG. 4 shows an example in which the first measurement device 111 is in a measurement position, i.e. in front of the pipe outlet. It is to be understood that the first measurement device 111 can be exchanged by the second measurement device 112 by simple rotation of the rotary holder 115.

[0050] With exemplary reference to FIG. 6, an evaporation source 200 for deposition of evaporated material on a substrate 10 according to embodiments of the present disclosure is described. According to embodiments, which can be combined with other embodiments described herein, the evaporation source 200 includes an evaporation crucible 220 and a distribution assembly 230 with a plurality of outlets 231 for providing evaporated materialtowards the substrate 10. Additionally, the evaporation source 200 includes at least one measurement assembly 100 according to embodiments described herein. As exemplarily shown in FIG. 6, typically the measurement outlet 205 is provided in a backwall 231 of the distribution assembly 230. Accordingly, the wall 201 of the evaporation source 200 through which the pipe 120 is provided is typically a backwall of the casing or housing of the evaporation source.

[0051] An "evaporation crucible" can be understood as a device having a reservoir for the material to be evaporated by heating the crucible. Accordingly, a "crucible" can be understood as a source material reservoir, which can be heated to evaporate the source material into a gas by at least one of evaporation and sublimation of the source material. The crucible can include a heater to evaporate the source material in the crucible into a gaseous source material. For instance, initially the material to be evaporated can be in the form of a powder or a grain. The reservoir can have an inner volume for receiving the source material to be evaporated, e.g. organic or inorganic materials, particularly metallic materials. FIG. 6 shows an evaporation crucible 220 containing source material 221 to be evaporated. The crucible 220 is in fluid communication with the distribution assembly 230 such that the evaporated material (indicated by the arrows in FIG. 6) can flow from the crucible into the distribution assembly 230.

[0052] The distribution assembly may include one or more distribution pipes configured for providing evaporated material towards the substrate. For instance, the one or more distribution pipes may provide a line source with a plurality of openings and / or nozzles which are arranged in lines along the length of the one or more distribution pipes. Accordingly, the distribution assembly can include a linear distribution showerhead, for example, having a plurality of openings, particularly nozzles, disposed therein. A showerhead as understood herein can have an enclosure, hollow space, or tube, in which the evaporated material can be provided or guided, for example from the evaporation crucible to the substrate. According to embodiments which can becombined with any other embodiments described herein, the length of the distribution pipe may correspond at least to the height of the substrate to be deposited. In particular, the length of the distribution pipe may be longer than the height of the substrate to be deposited, 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 instance, the source material to be deposited may be an organic or inorganic material, e.g. a metallic material, for use as electrode materials or electron transport layer materials in organic light emitting diode (OLED) production.

[0053] According to embodiments, which can be combined with other embodiments described herein, the at least one measurement assembly 100 of the evaporation source 200 comprises a first measurement assembly 100A and a second measurement assembly 100B arranged next to each other, particularly parallel to each other, as exemplarily shown in FIG. 5. Typically, the cooling element 210 is common to the first measurement assembly 100A and the second measurement assembly 100B.

[0019] FIG. 5 shows an exemplary configuration in which a first pipe 1201 is connected via a flange 1211 of the first pipe 1201 to the cooling element 210 provided at the wall 201 of an evaporation source, according to embodiments described herein. Additionally, a second pipe 1202 is connected via a flange 1212 of the second pipe 1202 to the same cooling element 210. The first pipe 1201 provides a passage for evaporated material from a first measurement outlet 205A through the wall 201 of the evaporation source to a first measurement device 1101. The second pipe 1202 provides a passage for evaporated material from a second measurement outlet 205B through the wall 201 of the evaporation source to a second measurement device 1102. Typically, the central axis 128A of the first pipe 1201 is parallel to the central axis 128B of the second pipe 1202. It is to be understood that the first measurement assembly 100A and the second measurement assembly 100B can be horizontally and / or vertically spaced from one another.

[0054] With exemplary reference to FIG. 7, a deposition apparatus 300 for deposition of evaporated material on a substrate 10 according to embodiments of the present disclosure is described. The deposition apparatus 300 includes a vacuum deposition chamber 310, and at least one evaporation source 200 provided inside the vacuum deposition chamber 210, according to any embodiments described herein.

[0055] The deposition apparatus 300 may also be referred to as a vacuum deposition apparatus. The vacuum deposition apparatus can be understood as an apparatus or configured for vacuum deposition of organic or inorganic materials including metallic materials, particularly for display manufacturing, e.g. for OLED display manufacturing.

[0056] In the present disclosure, a "vacuum deposition chamber" can 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 10’5mbar and about 10’8mbar, particularly between 10’5mbar and 10-7mbar.

[0057] In the present disclosure, a "substrate" can be understood as a material or object onto which some form of processing, treatment, or material deposition is applied. In particular, the substrate can be a large area substrate as described herein. Typically, the substrate is of transparent material, e.g. transparent glass or transparent plastic.

[0058] According to embodiments, which can be combined with other embodiments described herein, the substrate thickness can be from 0.1 to 1 .8 mm. For example, the substrate thickness can be about 0.9 mm or below, such as 0.5 mm. The term “substrate” as used herein may particularly embrace substantially inflexible substrates, e.g., a glass plate, a plastic plate or other suitable substrates. However, the present disclosure is not limited thereto andthe term “substrate” may also embrace flexible substrates such as a web or a foil. The term “substantially inflexible” is understood to distinguish over “flexible”. Specifically, a substantially inflexible substrate can have a certain degree of flexibility, e.g. a glass plate having a thickness of 0.9 mm or below, such as 0.5 mm or below, wherein the flexibility of the substantially inflexible substrate is small in comparison to the flexible substrates.

[0059] 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 holders 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 about 0.67 m2of substrate (0.73x0.92m), GEN 5, which corresponds to about 1 .4 m2substrates (1.1 m x 1 .3 m), GEN 6, which corresponds to about 2.7 m2(1.5 m x about 1.8 m), GEN 7.5, which corresponds to about 4.29 m2substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7 m2substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 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.

[0060] According to embodiments which can be combined with any other embodiments described herein, the deposition apparatus is configured for material deposition in a substantially vertical orientation of the substrate. Accordingly, typically the vacuum deposition chamber 310 and the evaporation source 200 are configured for material deposition on a substantially vertically arranged substrate 10. A substantially vertical orientation can be understood in that the orientation is vertical within a tolerance T of T < ±15°, particularly T < ±10°, from the perfect vertical orientation.

[0061] With exemplary reference to the block diagram shown in FIG. 8, a method 400 of measuring a disposition rate of evaporated material according to embodiments of the present disclosure is described. According to embodiments, which can be combined with other embodiments described herein, the method 400 includes providing (represented by block 410 in FIG. 8) evaporated material from a measurement outlet 205 of an evaporation source 200 through a wall 201 of the evaporation source 200 to a measurement device 110 by using a pipe 120. Additionally, the method 400 includes providing (represented by block 420 in FIG. 8) a cooling of the pipe 120. Further, the method 400 includes measuring (represented by block 430 in FIG. 8) the deposition rate with the measurement device 110.

[0062] It is to be understood that typically the method 400 of measuring a disposition rate of evaporated material is conducted by using a measurement assembly 100 according to any embodiments described herein.

[0063] According to embodiments which can be combined with any other embodiments described herein, the method 400 includes controlling (represented by block 440 in FIG. 8) an amount of evaporated material arriving at the measurement device 110 by selecting a nozzle size of a nozzle 206 providing the measurement outlet 205. Additionally or alternatively, controlling the amount of evaporated material arriving at the measurement device 110 may include using at least one rotating aperture disk 140 provided between a pipe outlet of the pipe 120 and the measurement device 110.

[0064] Accordingly, in view of the embodiments describe herein, it is to be understood that compared to the state of the art, an improved measurement assembly, an improved evaporation source, an improved deposition apparatus, and improved method of measuring a disposition rate of evaporated material are provided. In particular, embodiments disclosed herein offer distinct advantages over the state of the art, specifically with respect to measurement stability and precision. One of the advantages is that during the measurement of the deposition rate, unintended coating of adjacentcomponents caused by stray coating is substantially eliminated. Another advantage is related to the temperature control, which facilitates an improved temperature stability for the measurement device, ensuring that the environmental conditions do not compromise the accuracy of measurements. Further, there is a consequential reduction in the overall heat load on the measurement device, contributing to its longevity and sustained performance over time. A further advantage is the swift temperature stabilization capability of the measurement device, particularly evident when transitioning between different measurement devices. Accordingly, operational efficiency can be improved by minimizing downtime during device switches, ultimately optimizing the overall measurement process. Moreover, embodiments described herein address the issue of crosstalk between neighboring measurement assemblies. By effectively eliminating interference between adjacent measurement assemblies, embodiments of the present disclosure ensures that each measurement device operates independently and accurately, maintaining the integrity of the data collected.

[0065] In summary, the embodiments of the present disclosure not only address specific challenges related to stray coating, temperature stability, and crosstalk but also provide a combination of features which synergistically elevate the precision, efficiency, and reliability of the measurement process.

[0066] 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.

[0067] In particular, this written description uses examples to outline the disclosure, 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 combinedwith each other. The patentable scope is defined by the claims, and other examples are intended to be within the scope of the claims if the claims have structural elements that do not differ from the literal language of the claims, or if the claims include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

WHAT IS CLAIMED:1 . A measurement assembly (100) for measuring a deposition rate of an evaporation source, comprising:- a measurement device (110) for measuring the deposition rate, and- a pipe (120) for providing a passage for evaporated material from a measurement outlet (205) of the evaporation source through a wall (201 ) of the evaporation source to the measurement device (110), wherein the pipe (120) is connected via a flange (121 ) of the pipe (120) to a cooling element (210) provided at the wall (201).

2. The measurement assembly (100) of claim 1 , wherein the pipe (120) is comprised of a first pipe part (122) of a first material, particularly metallic material, and a second pipe part (123) of a second material, particularly metallic material, different from the first material, wherein the second material has a higher thermal conductivity than the first material.

3. The measurement assembly (100) of claim 2, wherein the first material is thermostable up to a temperature T of T=300°C, particularly T=600°C , more particularly T=900°C.

4. The measurement assembly (100) of claim 2 or 3, wherein the first material is steel, particularly stainless steel.

5. The measurement assembly (100) of any of claims 2 to 4, wherein the thermal conductivity k of the second material is k > 100 W nr1K’1, particularly k > 150 W m’1K’1.

6. The measurement assembly (100) of any of claims 2 to 5, wherein the second material is selected from the group consisting of aluminum, aluminum alloy, copper, copper alloy, and aluminum-copper alloy.

7. The measurement assembly (100) of any of claims 2 to 6, wherein the first pipe part (122) comprises a first flange (124), wherein the second pipe part (123) comprises a second flange (125), and wherein the first pipe part (122) and the second pipe part (123) are connected via the first flange (124) and the second flange (125).

8. The measurement assembly (100) of any of claims 1 to 7, wherein the cooling element (210) is a passive cooling element, particularly a cooling plate providing a heat sink, or wherein the cooling element (210) is connected to an active cooling, particularly a water cooling.

9. A measurement assembly (100) for measuring a deposition rate of an evaporation source, comprising:- a measurement device (110) for measuring the deposition rate, and- a pipe (120) for providing a passage for evaporated material from a measurement outlet (205) of the evaporation source through a wall (201 ) of the evaporation source to the measurement device (110), wherein the pipe (120) is connected via a flange (121 ) of the pipe (120) to a cooling element (210) provided at the wall (201), and- at least one rotatable aperture disk (140) provided between the pipe (120) and the measurement device (110).

10. The measurement assembly (100) of claim 9, wherein the at least one rotatable aperture disk (140) comprises a first aperture (141 ) and a second aperture (142), particularly wherein the first aperture (141) and the second aperture (142) are point-symmetrical with respect to a rotation axis (144) of the at least one rotatable aperture disk (140).11 . The measurement assembly (100) of claim 9 or 10, wherein a total size of the first aperture (141 ) and the second aperture (142) is selected, such that an amount of evaporated material arriving at the measurement device (110) is reduced by 25% or more, particularly by 35% or more,more particularly by 50% or more, as compared to an amount of evaporated material introduced into the pipe (120).

12. The measurement assembly (100) of any of claims 9 to 11 , wherein the at least one rotatable aperture disk (140) is connected to a drive (150), particularly via a shaft (143), wherein the drive (150) is configured for rotating the at least one rotatable aperture disk (140) with a rotational speed, such that the frequency of evaporated material provided to the measurement device (110) is higher than the detection frequency of the measurement device (110).

13. The measurement assembly (100) of any of claims 9 to 12, wherein a frontside (140F) and / or a backside (1406) of the at least one rotatable aperture disk (140) has an emissivity £ < 0.5.

14. The measurement assembly (100) of claim 13, wherein the backside (1406) of the at least one rotatable aperture disk (140) has a lower emissivity £ than the frontside (140F) of the at least one rotatable aperture disk (140).

15. The measurement assembly (100) of claim 13 or 14, wherein the backside (1408) of the at least one rotatable aperture disk (140) is configured to have an emissivity £ < 0.4, particularly £ < 0.3, more particularly £ < 0.2.

16. The measurement assembly (100) of any of claims 9 to 15, wherein the at least one rotatable aperture disk (140) comprises a stack (145) of two or more rotatable aperture disks (140).

17. The measurement assembly (100) of claim 16, wherein a distance d between two neighboring aperture disks (140) of the stack (145) is selected from a range between a lower limit d-i and an upper limit d2,wherein the lower limit d-i is d-i = 0.2 mm, particularly d-i = 0.4 mm, more particularly d-i = 0.8 mm, and the upper limit d2is d2= 2 mm, particularly d2= 3 mm, more particularly d2= 5 mm.

18. The measurement assembly (100) of claim 16 or 17, wherein apertures of the two or more aperture disks (140) of the stack (145) are arranged such that the apertures at least partially overlap when viewed in direction of a central rotation axis (144) of the stack (145), particularly wherein the apertures of the two or more aperture disks (140) of the stack (145) are aligned with respect to each other.

19. An evaporation source (200) for deposition of evaporated material on a substrate (10), comprising:- an evaporation crucible (220);- a distribution assembly (230) with a plurality of outlets (231 ) for providing evaporated material towards the substrate (10); and- at least one measurement assembly (100) according to any of claims 1 to 18.

20. The evaporation source (200) of claim 19, wherein the measurement outlet (205) is provided in a backwall of the distribution assembly (230).21 . The evaporation source (200) of claim 19 or 20, wherein the measurement outlet (205) comprises a nozzle (206) to direct evaporated material into the pipe (120) in the direction of a central axis (128) of the pipe (120).

22. The evaporation source (200) of claim 21 , wherein the nozzle (206) at least partially extends into the pipe (120).

23. The evaporation source (200) of any of claims 19 to 22, wherein the at least one measurement assembly (100) comprises a first measurementassembly (100A) and a second measurement assembly (100B) arranged next to each other, particularly parallel to each other, and wherein the cooling element (210) is common to the first measurement assembly (100A) and the second measurement assembly (100B).

24. A deposition apparatus (300) for deposition of evaporated material on a substrate, comprising:- a vacuum deposition chamber (310), and- at least one deposition source (200) according to any of claims 19 to 23 provided inside the vacuum deposition chamber 210.

25. A method (400) of measuring a disposition rate of evaporated material, comprising:- providing (410) evaporated material from a measurement outlet (205) of an evaporation source (200) through a wall (201 ) of the evaporation source (200) to a measurement device (110) by using a pipe (120),- providing (420) a cooling of the pipe (120), and- measuring (430) the deposition rate with the measurement device (110).

26. The method (400) of claim 25, wherein the measurement outlet (205) includes a nozzle (206), and wherein the method further comprises controlling (440) an amount of evaporated material arriving at the measurement device (110) by selecting a nozzle size and / or by using at least one rotating aperture disk (140) provided between a pipe outlet of the pipe (120) and the measurement device (110).

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