WO2019011449A1

WO2019011449A1 - Method for cleaning a component of a material deposition source, method for the manufacture of a material deposition source, and apparatus for cleaning a component of a material deposition source

Info

Publication number: WO2019011449A1
Application number: PCT/EP2017/067918
Authority: WO
Inventors: Thomas Gebele; Michael REINFURTH
Original assignee: Applied Materials, Inc.
Priority date: 2017-07-14
Filing date: 2017-07-14
Publication date: 2019-01-17
Also published as: CN110352100A

Abstract

The present disclosure provides a method (100) for cleaning a component (20) of a material deposition source (400). The method (100) includes inserting (110) the component (20) into a cleaning liquid (201), inserting (120) an ultrasonic source (220) into an interior of the component (20), and operating (130) the ultrasonic source (220).

Description

METHOD FOR CLEANING A COMPONENT OF A MATERIAL DEPOSITION

SOURCE, METHOD FOR THE MANUFACTURE OF A MATERIAL DEPOSITION SOURCE, AND APPARATUS FOR CLEANING A COMPONENT

OF A MATERIAL DEPOSITION SOURCE

FIELD [0001] Embodiments of the present disclosure relate to a method for cleaning a component of a material deposition source, a method for the manufacture of a material deposition source, and an apparatus for cleaning a component of a material deposition source. Embodiments of the present disclosure particularly relate to methods and apparatuses used in the manufacture of organic light-emitting diode (OLED) devices.

BACKGROUND

[0002] Techniques for layer deposition on a substrate include, for example, thermal evaporation, physical vapor deposition (PVD), and chemical vapor deposition (CVD). Coated substrates may be used in several applications and in several technical fields. For instance, coated substrates may be used in the field of organic light emitting diode (OLED) devices. OLEDs can be used in the manufacture of television screens, computer monitors, mobile phones, other hand-held devices and the like for displaying information. An OLED device, such as an OLED display, may include one or more layers of an organic material situated between two electrodes that are all deposited on a substrate. [0003] OLED devices can include a stack of several organic materials, which are for example evaporated in a vacuum chamber of a processing apparatus. The organic materials are deposited on a substrate in a subsequent manner through shadow masks using evaporation sources. The vacuum conditions inside the vacuum chamber are crucial for a quality of the deposited material layers and the OLED devices manufactured using these material layers.

[0004] Therefore, there is a need for a method and an apparatus that can improve vacuum conditions inside a vacuum chamber. The present disclosure particularly aims at improving a cleanliness of components inside the vacuum chamber such that a quality of layers of an organic material deposited on a substrate can be improved.

SUMMARY [0005] In light of the above, a method for cleaning a component of a material deposition source, a method for the manufacture of a material deposition source, and an apparatus for cleaning a component of a material deposition source are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings. [0006] According to an aspect of the present disclosure, a method for cleaning a component of a material deposition source is provided. The method includes inserting the component into a cleaning liquid, inserting an ultrasonic source into an interior of the component, and operating the ultrasonic source.

[0007] According to another aspect of the present disclosure, a method for the manufacture of a material deposition source is provided. The method includes cleaning one or more components of the material deposition source by inserting an ultrasonic source into an interior of the one or more components, and assembling the material deposition source using the one or more components.

[0008] According to a further aspect of the present disclosure, an apparatus for cleaning a component of a material deposition source is provided. The apparatus includes a tank configured to accommodate the component, and an ultrasonic source configured to be inserted into an interior of the component.

[0009] According to a yet further aspect of the present disclosure, an apparatus for cleaning a component of a material deposition source is provided. The apparatus includes a tank configured to accommodate the component, a first ultrasonic source configured to clean the inside of the component, and a second ultrasonic source configured to clean the outside of the component. [0010] 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 apparatus include method aspects for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 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 flowchart of a method for cleaning a component of a material deposition source used in the manufacture of OLED devices according to embodiments described herein;

FIG. 2 shows a schematic view of an apparatus for cleaning component of a material deposition source according embodiments described herein;

FIG. 3 shows a flowchart of a method for the manufacture of a material deposition source according to embodiments described herein;

FIG. 4 shows a schematic view of a material deposition source used in the manufacture of OLED devices according to embodiments described herein; and FIG. 5 shows a schematic view of a system for the manufacture of devices having organic materials according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0012] 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. Generally, 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. [0013] The vacuum conditions inside of a vacuum chamber can be crucial for the quality of material layers deposited on a substrate. In particular, for OLED mass production, the cleanliness of all vacuum components is essential. Even electro-polished and other smooth metal surfaces may be too dirty for OLED device fabrication and need dedicated cleaning procedures to achieve UCV (Ultra Clean Vacuum). The present disclosure uses an ultrasonic source that is inserted into a component of a material deposition source, such as a distribution pipe of an evaporation source, to efficiently clean the component from the inside. Contaminations can be removed from hollow parts having for instance inside welding, edge areas, and/or overlapping portions. The cleanliness levels can be significantly enhanced and a quality of the layers deposited on a substrate can be improved. This is in particular beneficial for the lifetime of the OLED devices produced/manufactured in the vacuum chamber.

[0014] FIG. 1 shows a flowchart of a method 100 for cleaning a component of a material deposition source used for instance in the manufacture of OLED devices according to embodiments described herein. [0015] The method 100 includes inserting or immersing the component into a cleaning liquid (block 110), inserting an ultrasonic source, such as a sonotrode, into an interior of the component (block 120), and operating the ultrasonic source (block 130). A cleanness of the component, such as a distribution pipe of an evaporation source used in OLED manufacturing, can be significantly enhanced and the quality OLED devices manufactured using he cleaned component(s) can be improved.

[0016] The present disclosure can achieve high hydrocarbon (HC) and/or plasticizer cleanness values (e.g. amu = 45 to 100 and amu = 101 to 200) which are beneficial for OLED manufacturing. For example, RGA class B 1 or B2 can be achieved: Bl (purity):

• Total desorption incl. water after 1 h: <5E-8 mbarl/(s*cm2) or <5E-9 mbarl/(s*cm2) after 10 h

• Hydrocarbons with mass <= 100 after 10 h: <5E-12 mbarl/(s*cm2)

• Optional RGA certificate amu 1 to 200: Mandatory for 1st article cleaning - optional number per batch

B2 (purity):

• Total desorption incl. water after 1 h: <1Ε-8 mbarl/(s*cm2) or <1Ε-9 mbarl/(s*cm2) after 10 h

• Hydrocarbons with mass <= 100 after 10 h: <4E-12 mbarl/(s*cm2) · Hydrocarbons with mass > 100 and mass <= 200 after 10 h: <3E-13 mbarl/(s*cm2)

[0017] No long-time (e.g. 24 hours) vacuum annealing or bake out at high temperatures, such as 500 °C or above, has to be performed. In particular, RGA (residual gas analysis) shows that high cleanness levels (UCV) can be achieved in a short time, such as 5 to 10 minutes, and at reduced costs. Accordingly, vacuum conditions and thus the purity of an organic material deposited on a substrate can be improved, leading to an improvement in the lifetime of the manufactured OLED devices. [0018] According to some embodiments, which can be combined with other embodiments described herein, the ultrasonic source can be operated to perform one or more cleaning cycles. The one or more cleaning cycles can be performed for a predetermined duration (i.e., a predetermined period of time). The duration can be selected such that a cleanness value of e.g. amu = (40)45 to 100 of amu = 101 to 200(300) can be provided after completion of the cleaning procedure (measured using RGA). The cleanness value "amu" can be defined as the sum of RGA measured partial pressures mass (AMU) (40)45 to 100 and 101 to 200(300). In some implementations, the duration of each cleaning cycle can be in the range between 60s and 240s, specifically in the range between 100s and 200s, and can specifically be about 240s.

[0019] According to some embodiments, the ultrasonic source can be repeatedly operated to perform two or more cleaning cycles, such as three or more (e.g. six) cleaning cycles. Each cleaning cycle can have a duration in the range between 60s and 240s, specifically in the range between 100s and 200s, and specifically of about 240s. In some exemplary embodiments, the durations of the two or more cleaning cycles can be essentially the same. In other exemplary embodiments, the durations of the two more cleaning cycles can be different. For example, the duration may get longer or shorter during the course of the cleaning procedure. The two or more cleaning cycles can be sequentially performed with a break between two consecutive cleaning cycles. The ultrasonic source can be switched on during the cleaning cycle(s) and can be switched off during the break e.g. using an ON/OFF parameter setting.

[0020] In some embodiments, a power generator can be connected to the ultrasonic source to operate the ultrasonic source. The power generator can operate the ultrasonic source at a predetermined power and/or predetermined frequency. The predetermined power can be a power that is transferred from the ultrasonic source to the cleaning liquid surrounding the ultrasonic source, e.g. in a resonance state. The predetermined frequency can be at, or close, to a resonance frequency defined by the ultrasonic source, the component of the material deposition source, the tank, and/or the cleaning liquid.

[0021] In an exemplary embodiment, the ultrasonic source is configured to provide a predetermined power in the range between 0.2kW to 2kW, specifically in the range between 0.2kW to IkW, more specifically in the range between 0.3kW and 0.5kW. The predetermined frequency can be in the range between 20kHz and 40kHz, specifically in the range between 25kHz and 35kHz, specifically in the range between 29kHz and 31kHz, and can be about 29kHz or 30kHz.

[0022] According to some embodiments, which can be combined with other embodiments described herein, the cleaning liquid has a (predetermined) temperature in the range between 40°C and 80°C, specifically in the range between 50°C and 70°C, and can more specifically have a temperature of about 60°C. One or more heating devices can be provided to adjust the temperature of the cleaning liquid. For example, the one or more heating devices can be controlled to maintain the temperature of the cleaning liquid at a predetermined temperature. The cleaning liquid (also referred to as "cleaning solution" or "bath") can contain one or more components, such as at least one of a surfactant, a detergent, and water. For example, the cleaning liquid can include one or more organic acids, and can particularly be an acid foaming liquid based on organic acids.

[0023] According to some embodiments, which can be combined with other embodiments described herein, the method 100 further includes a removal process to remove residual cleaning liquid from the component. The removal process can be performed after the cleaning process using the ultrasonic source, and particularly after the component has been removed from (e.g. pulled out of) the cleaning liquid and/or tank. The removal process can use water to remove the residual cleaning liquid from the component. For example, the removal process can include a DI (deionized) water spray and/or rinsing and/or dipping procedure. Additionally or alternatively, the method 100 may further include a drying process to dry the component. The drying process can include a heating of the component. For example, the component can be dried in a cleanroom e.g. for RGA measurements. [0024] In some implementations, the method 100 further includes a moving of the ultrasonic source in the interior of the component. For example, the ultrasonic source can be moved to position the ultrasonic source inside the tank and/or the component such that a power transmitted from the ultrasonic source into the cleaning liquid, i.e., the predetermined power, is adjusted or maximized. The ultrasonic source can for instance be moved in a longitudinal direction thereof (e.g. in a vertical direction) and/or a lateral direction (e.g. in a horizontal direction) to optimize the cleaning result. [0025] According to some embodiments, which can be combined with other embodiments described herein, the method 100 further includes a controlling of a filling of the bath, i.e., the cleaning liquid. For example, a filling and/or refilling of the bath can be controlled. A filling level of the bath can be controlled e.g. after the completion of a cleaning procedure of a component and before the start of a cleaning procedure of another component. The filling level of the bath can be controlled such that the component to be cleaned is completely immersed in the cleaning liquid. In further examples, the bath can be refilled for instance after the completion of a cleaning procedure of a component and before the start of a cleaning procedure of another component to compensate for a loss of cleaning liquid.

[0026] The method 100 can, in some embodiments, include an adjustment of one or more parameters selected from the group consisting of the duration of the cleaning cycle(s), the number of cleaning cycles, the predetermined frequency, the predetermined power, a predetermined amplitude of the ultrasound, the position of the ultrasonic source, ON/OFF settings of the ultrasonic source, a bath filling, a bath temperature (the predetermined temperature), and the like. The one or more parameters can be adjusted to optimize the cleaning result. In some implementations, the chemical and/or physical quality of the cleaning liquid can be controlled, e.g., continuously. For example, a part of the cleaning liquid can be continuously pumped through appropriate devices. Optionally or alternatively, the cleaning liquid can be continuously renewed using e.g. an external tank or reservoir.

[0027] According to some embodiments, which can be combined with other embodiments described herein, the method 100 further includes an operating of another ultrasonic source, such as another sonotrode, which is positioned inside the tank and the cleaning liquid and is positioned outside the component of the material deposition source. In other words, the other ultrasonic source can be positioned between an inner surface of the tank and an outer surface of the component. The other ultrasonic source can be used to clean the outside of the component. In further implementations, the other ultrasonic source can be provided outside the tank or bath. For example, the other ultrasonic source can be connected to the wall of the tank. [0028] According to some embodiments, which can be combined with other embodiments described herein, the component of the material deposition source is selected from the group consisting of a distribution pipe, such as a Titanium distribution pipe or tube, an evaporation crucible, and a combination thereof. For example, the material deposition source can be an evaporation source configured for evaporation of an organic material for the manufacture of OLED devices.

[0029] In an exemplary cleaning procedure, a component of a material deposition source, such as a distribution pipe or tube, underwent three cleaning cycles each having a duration of about 140s. The ultrasonic source, which was a sonotrode, was operated at a frequency of about 29kHz and an amplitude of 40% to 50%, providing a power of 300 to 500W. The cleaning liquid (bath) had a temperature of about 60C°. The bath was a standard cleaner that can be refilled after each tube. After 3x140s of ultrasonic cleaning, the cleaner was removed from the tube with a standard DI water spray procedure and the tube was dried in a cleanroom for RGA measurements. RGA results showed a reduction from 12x to 1.4x from the HC limit. Thus, HC cleanness was improved by a factor of about 8 to 9.

[0030] According to embodiments described herein, the method for cleaning a component of a material deposition source can be conducted using computer programs, software, computer software products and the interrelated controllers, which can have a CPU, a memory, a user interface, and input and output means devices in communication with the corresponding components of the apparatus for processing a large area substrate.

[0031] FIG. 2 shows a schematic view of an apparatus 200 for cleaning a component 20 of a material deposition source according to embodiments described herein. In some implementations, the apparatus 200 is an (fully) automated apparatus 200 configured to perform the cleaning procedure automatically. [0032] The apparatus 200 includes a tank 210 configured to accommodate the component 20, and an ultrasonic source 220 configured to be inserted into an interior of the component 20, particularly when the component 20 is accommodated in the tank 210. The apparatus 200 may include a controller 230 configured to perform the method for cleaning a component of a material deposition source according to the present disclosure. [0033] In some implementations, the component 20 is selected from the group including a distribution pipe (or tube), an evaporation crucible, and a combination thereof. The tank 210 can be configured to accommodate the distribution pipe and/or the evaporation crucible. For example, the tank 210 can be configured to accommodate either the distribution pipe or the evaporation crucible, or can be configured to accommodate both the distribution pipe and the evaporation crucible. In the latter case the distribution pipe and the evaporation crucible can be separated or mounted together. An exemplary material deposition source is explained with respect to FIG. 4.

[0034] The tank 210, which can be a tube, is configured to contain the cleaning liquid 201, which is also referred to as "bath" or "cleaning bath". The tank 210 can have a volume of at least 10 liter, specifically at least 100 liters, and more specifically at least 1000 liter. In some implementations, the tank 210 can have a height of at least lm, and can specifically have a height in the range between lm and 2m. In some implementations, the tank 210 can be made of metal, such as steel, a steel alloy, or aluminum. For example, the tank 210 can be a DN250 or DN 320 tube.

[0035] For cleaning the component 20, the component 20 can be first lifted and then lowered (e.g. dipped) into the tank 210 using a handling/lifting tool such that the component 20 is completely immersed in the cleaning liquid 201. Thereafter, the ultrasonic source 220 can be inserted (e.g. lowered) into the component 20 and thus into the tank 210 and the cleaning liquid 201. In other embodiments, the component 20 and the ultrasonic source 220 can be assembled outside the tank 210 and can then be jointly lifted and then lowered (e.g. dipped) into the tank 210 using the handling/lifting tool such that the component 20 is completely immersed in the cleaning liquid 201

[0036] Before the component 20 is lowered into the tank 210, the component 20 can be prepared for the cleaning procedure. For example, the component 20 can be pre-cleaned. The ultrasonic source 220 can be centered using an external holder relative to the component 20 to be cleaned or a spacer between ultrasonic source 220 and the component 20. For example, the ultrasonic source can be centered at at least one of externally and relatively to the component 20 using one or more spacers. [0037] The component 20 can have a first end portion and a second end portion opposite the first end portion. The first end portion can be a top side of the component 20 and the second end portion can be a bottom side of the component 20. In further embodiments, the first end portion can be a bottom side of the component 20 and the second end portion can be a top side of the component 20. For example, the at least one centering device can be mountable (or mounted) to a bottom of a distribution pipe. The distribution pipe can be lowered into the tank 210 upside down. In particular, an opening can be provided at the bottom of the distribution pipe through which the ultrasonic source 220 can be inserted into a distribution pipe. The distribution pipe may have one or more openings, such as nozzles, at a lateral side thereof, such that cleaning liquid can flow into the distribution pipe. Other parts may have to be filled with liquid or plunged. Inserting the ultrasonic source 220 into the component 20 is particularly beneficial because the openings of the distribution pipe, such as the nozzles and the opening at the bottom, are generally too small to transfer enough ultrasonic power from the outside of the distribution pipe to the inside. [0038] The apparatus 200 can include a power supply 232 configured to operate the ultrasonic source 220. The power supply 232 and the controller 230 can be provided as one entity ("ultrasonic power generator"). The power supply 232 can be configured to provide the predetermined frequency, the predetermined power, and the predetermined amplitude to operate the ultrasonic source 220. The predetermined frequency, the predetermined power, the predetermined amplitude, and/or the duration of the cleaning cycle(s) can be referred to as "generator settings". The generator settings can be chosen to optimize a cleaning result.

[0039] According to some embodiments, which can be combined with other embodiments described herein, the ultrasonic source 220 is a sonotrode. The sonotrode is configured to create ultrasonic vibrations and apply this vibrational energy to the cleaning liquid. The sonotrode may include a resonance body 222 and one or more piezoelectric elements 224 attached to the resonance body 222. The resonance body 222 can be a tapering metal rod. An alternating current oscillating at the predetermined frequency (i.e., an ultrasonic frequency) and having the predetermined amplitude is applied by the power supply 232 to the one or more piezoelectric elements 224. The current causes the one or more piezoelectric elements 224 to expand and contract. The predetermined frequency of the current can be chosen to be the resonant frequency of the sonotrode, so the entire sonotrode acts as a half-wavelength resonator, vibrating lengthwise with standing waves at the resonant frequency.

[0040] The ultrasonic source 220, and particularly the resonance body 222 of the ultrasonic source 220, can have a length of at least 0.5m, specifically at least lm, and more specifically at least 1.5m. For example, the length of the ultrasonic source 220, and particularly the resonance body 222, can be in the range between 0.5m and 2m, specifically in the range between lm and 1.5m, and can more specifically be about 1.3m, such as 1.28m. The ultrasonic source 220, and particularly the resonance body 222 of the ultrasonic source 220, can have a diameter in the range between 10mm and 50mm, specifically in the range between 20mm and 40mm, and can more specifically be about 30mm.

[0041] In some implementations, a volume of the ultrasonic source 220, and particularly of the resonance body 222 (e.g. defined as the height times the diameter of the resonance body), can correspond to at least 10%, specifically at least 25%, specifically at least 50%, specifically at least 75%, and more specifically at least 90% of a volume of the interior of the component 20 to define a fill factor. The fill factor can be selected to optimize a cleaning result.

[0042] According to some embodiments, which can be combined with other embodiments described herein, the apparatus includes the ultrasonic source 220 (first ultrasonic source) and another ultrasonic source (second ultrasonic source), such as another sonotrode, positioned inside the tank 210 but outside the component 20 of the material deposition source. In other words, the other ultrasonic source can be positioned between an inner surface of the tank 210 and an outer surface of the component 20. The other ultrasonic source can be used to clean the outside of the component 20. In some implementations, the same ultrasonic source (e.g. the first ultrasonic source) is used for both cleaning the inside and the outside of the component 20 in sequence. The tank 210 may be larger if the other ultrasonic source is provided and may be smaller if only the ultrasonic source 220 is provided. In some embodiments, the other ultrasonic source can be fixed to the tank 210 and the ultrasonic source 220 is removable. [0043] According to some embodiments, which can be combined with other embodiments described herein, the apparatus 200 includes one or more heating devices 240 configured to heat the cleaning liquid 201 to a predetermined temperature. The predetermined temperature can be in the range between 40°C and 80°C, specifically in the range between 50°C and 70°C, and can more specifically be about 60°C. The one or more heating devices 240 can be resistance heaters.

[0044] According to some embodiments, the apparatus 200 includes a level sensor configured to sense a level of the cleaning liquid 201. The level of the component 20 can be defined by a surface 202 of the cleaning liquid 201. The controller 230 can be configured to control a filling of the bath, i.e., the cleaning liquid. For example, a filling and/or refilling of the bath can be controlled such that the level sensed by the level sensor corresponds to a predetermined level. A filling level of the bath can be controlled e.g. after the completion of a cleaning procedure of a component and before the start of a cleaning procedure of another component. The filling level of the bath can be controlled such that the component to be cleaned is completely immersed in the cleaning liquid, i.e., such that the entire component is below the surface 202 of the cleaning liquid 201. In further examples, the bath can be refilled for instance after the completion of a cleaning procedure of a component and before the start of a cleaning procedure of another component to compensate for a loss of cleaning liquid. [0045] FIG. 3 shows a flowchart of a method 300 for the manufacture of a material deposition source used for vacuum deposition on a substrate to manufacture OLED devices. The method 300 can include the aspects of the method for cleaning a component of a material deposition source according to the present disclosure.

[0046] The method 300 includes in block 310 a cleaning of one or more components of the material deposition source by inserting an ultrasonic source into an interior of the one or more components, and in block 320 an assembling of the material deposition source using the one or more components. The material deposition source can be assembled for use in a vacuum deposition system, such as a vacuum deposition system for the manufacture of OLED devices. In particular, the method 300 can further include installing the assembled material deposition source in a vacuum chamber of the vacuum deposition system. [0047] FIG. 4 shows a schematic view of a material deposition source used in the manufacture of OLED devices according to embodiments described herein. The material deposition source can be an evaporation source.

[0048] FIG. 4 shows a schematic view of an evaporation source 400 having a distribution assembly 430, an evaporation crucible 440, and an optional shaper device 420 configured to delimit a distribution cone of the material evaporated by the evaporation source 400.

[0049] The evaporation source 400 may include the distribution assembly 430 connected to the evaporation crucible 440. For example, the distribution assembly 430 may include a distribution pipe which can be an elongated tube. For instance, a distribution pipe as described herein may provide a line source with a plurality of openings and/or nozzles which are arranged in at least one line along the length of the distribution pipe. Alternatively, one elongated opening extending along the at least one line can be provided. For example, the elongated opening can be a slit. According to some embodiments, which can be combined with other embodiments described herein, the line may be essentially vertical.

[0050] In some implementations, the distribution assembly 430 may include a distribution pipe which is provided as a linear distribution showerhead, for example, having a plurality of openings disposed therein. A showerhead as understood herein has an enclosure, hollow space, or pipe, in which the material can be provided or guided, for example from the evaporation crucible 440. The showerhead can have a plurality of openings (or an elongated slit) such that the pressure within the showerhead is higher than outside the showerhead. For example, the pressure within the showerhead can be at least one order of magnitude higher than outside the showerhead.

[0051] According to some embodiments, which can be combined with any other embodiments described herein, the length of the distribution pipe may correspond at least to the height of the substrate to be coated. In particular, the length of the distribution pipe may be longer than the height of the substrate to be coated, at least by 10% or even 20%. For example, the length of the distribution pipe can be 1.3 m or above, for example 2.5 m or above. Accordingly, a uniform deposition at the upper end of the substrate and/or the lower end of the substrate can be provided. According to an alternative configuration, the distribution assembly 430 may include one or more point sources which can be arranged along a vertical axis.

[0052] According to some embodiments, which can be combined with other embodiments described herein, the evaporation crucible 440 is in fluid communication with the distribution assembly 430 and is provided at the lower end of the distribution assembly 430. In particular, a connector, e.g. a flange unit may be provided, which is configured to provide a connection between the evaporation crucible 440 and the distribution assembly 430. For example, the evaporation crucible 440 and the distribution assembly 430 may be provided as separate units, which can be separated and connected or assembled at the connector, e.g. for operation of the evaporation source 400. The evaporation crucible 440 can be a reservoir for a material, such as an organic material, to be evaporated by heating the evaporation crucible 440. The evaporated material may enter the distribution assembly 430, particularly at the bottom of the distribution pipe, and may be guided essentially in a sideward direction through the plurality of openings in the distribution pipe, e.g., towards an essentially vertically oriented substrate.

[0053] According to some embodiments, a heating unit 410 may be provided for heating the distribution assembly 430, and particularly the distribution pipe(s). The heating unit 410 may be mounted or attached to walls of the distribution assembly 430. The distribution assembly 430 can be heated to a temperature such that the vapor of the material, which is provided by the evaporation crucible 440, does not condense at an inner portion of the wall of the distribution assembly 430. Further, a heat shield may be provided around the distribution pipe to reflect heat energy provided by the heating unit 410 back towards the distribution pipe.

[0054] The evaporation source 400 may include the shaper device 420 (also referred to as "shielding device", "shaper shielding device" or "hot shaper") to delimit the distribution cone of evaporated material provided to the substrate. Further, the shaper device 420 may be configured to reduce the heat radiation towards the deposition area. In some implementations, the shaper device 420 may be cooled by a cooling element 422. For example, the cooling element 422 may be mounted to the backside of the shaper device 420 and may include a conduit for cooling fluid. [0055] In some implementations, the evaporation source 400 can be configured for a rotation around an axis, particularly during evaporation. A rotation drive may be provided, for example, at the connections between a source cart (not shown) and the evaporation source 400. The rotation drive can be configured for turning the evaporation source 400 essentially parallel to the substrate before the coating of the substrate is carried out. Various applications for OLED device manufacture include processes where two or more organic materials are evaporated simultaneously. In some embodiments, two or more distribution assemblies, particularly distribution pipes and corresponding evaporation crucibles, can be provided next to each other. Such an evaporation source may also be referred to as an evaporation source array, e.g. wherein more than one kind of organic material is evaporated at the same time.

[0056] FIG. 5 shows a system 500 for depositing one or more layers e.g. of an organic material on a substrate according to embodiments described herein. The system 500 exemplarily illustrates a stationary substrate and a moving deposition source. However, the present disclosure is not limited thereto and the deposition source can be stationary and the substrate can be moving during the layer deposition process.

[0057] The system 500 includes the material deposition source that has been cleaned during manufacturing according to the embodiments described herein in a vacuum chamber 540. The system 500 may further include a load lock chamber 501 connected to the vacuum chamber 540 for loading the substrate into the vacuum chamber 540, and an unload lock chamber 502 connected to the vacuum chamber 540 for unloading the substrate having the one or more layers deposited thereon from the vacuum chamber 540. The system 500 can be configured for deposition of an organic material.

[0058] The material deposition source can be provided on a track or linear guide 522. The linear guide 522 may be configured for a translational movement of the material deposition source. Further, a drive for providing a translational movement of the material deposition source can be provided. The vacuum chamber 540 may be connected to the load lock chamber 501 and the unload lock chamber 502 via respective gate valves. The gate valves can allow for a vacuum seal between adjacent vacuum chambers and can be opened and closed for moving a substrate and/or a mask into or out of the vacuum chamber 540. [0059] According to some embodiments, which can be combined with any other embodiment described herein, two substrates, e.g. a first substrate 10A and a second substrate 10B, can be supported on respective transportation tracks within the vacuum chamber 540. Further, two tracks for providing masks thereon can be provided. In particular, coating of the substrates may include masking the substrates with respective masks, e.g. with an edge exclusion mask or a shadow mask. According to some embodiments, the masks, e.g. a first mask 30A corresponding to the first substrate 10A and a second mask 30B corresponding to a second substrate 10B, are provided in a mask frame 530 to hold the mask in a predetermined position. [0060] According to some embodiments, which can be combined with other embodiments described herein, the substrates can be supported by a respective carrier, which can be connected to an alignment system 550, e.g. by connecting elements 552. An alignment system 550 can adjust the position of the substrate with respect to the mask. The substrate can be moved relative to the mask in order to provide for a proper alignment between the substrate and the mask during deposition of the material. According to a further embodiment, which can be combined with other embodiments described herein, alternatively or additionally the mask and/or the mask frame 530 holding the mask can be connected to the alignment system 550. Either the mask can be positioned relative to the substrate or the mask and the substrate can both be positioned relative to each other. [0061] According to some embodiments, a source support 531 configured for the translational movement of the material deposition source along the linear guide 522 may be provided. The source support 531 can support the evaporation crucible 440 and the distribution assembly 430 provided over the evaporation crucible 440. Vapor generated in the evaporation crucible 440 can move upwardly and out of the one or more outlets of the distribution assembly 430. The distribution assembly 430 is configured for providing evaporated material, particularly a plume of evaporated source material, from the distribution assembly 430 to the substrate.

[0062] The material deposition source may include the shaper device 420. Additionally, a material collection unit 560 may be arranged in the vacuum chamber 540 to collect evaporated source material emitted from the material deposition source, e.g. the evaporation source, when the material deposition source is in a rotated position. The heating device 570 may be provided for cleaning the shaper device 420 in a service position of the material deposition source. The service position may be a position of the material deposition source in which the outlets of the distribution assembly 430 are in a rotated position as compared to a deposition position of the distribution assembly 430 in which the outlets are directed towards a substrate to be coated.

[0063] The embodiments described herein can be utilized for evaporation on large area substrates, e.g., for display manufacturing. Specifically, the substrates for which the structures and methods according to embodiments described herein are provided, are large area substrates. For instance, a large area substrate or carrier can be GEN 4.5, which corresponds to a surface area of about 0.67 m² (0.73 x 0.92m), GEN 5, which corresponds to a surface area of about 1.4 m² (1.1 m x 1.3 m), GEN 7.5, which corresponds to a surface area of about 4.29 m² (1.95 m x 2.2 m), GEN 8.5, which corresponds to a surface area of about 5.7m² (2.2 m x 2.5 m), or even GEN 10, which corresponds to a surface area of about 8.7 m² (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding surface areas can similarly be implemented. Half sizes of the Gen generations may also be provided in OLED display manufacturing.

[0064] The present disclosure uses an ultrasonic source that is inserted into a component of a material deposition source, such as a distribution pipe of an evaporation source, to efficiently clean the component on the inside. Contaminations can be removed from hollow parts having for instance inside welding, edge areas, and/or overlapping portions. The cleanliness levels can be significantly enhanced and a quality of the layers deposited on a substrate can be improved.

[0065] 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.

Claims

1. A method for cleaning a component of a material deposition source, comprising: inserting the component into a cleaning liquid; inserting an ultrasonic source into an interior of the component; and operating the ultrasonic source.

2. The method of claim 1, wherein the component of the material deposition source is selected from the group consisting of a distribution pipe, an evaporation crucible, and a combination thereof.

3. The method of claim 1 or 2, wherein the ultrasonic source is repeatedly operated to perform two or more cleaning cycles.

4. The method of any one of claims 1 to 3, wherein each cleaning cycle of the two or more cleaning cycles has a duration in the range between 60s and 240s.

5. The method of any one of claims 1 to 4, wherein the ultrasonic source provides a power in the range between 0.2kW and 2kW.

6. The method of any one of claims 1 to 5, wherein the cleaning liquid has a temperature in the range between 50°C and 70°C.

7. The method of any one of claims 1 to 6, further comprising at least one of: a removal process to remove residual cleaning liquid from the component; a drying process to dry the component; and moving the ultrasonic source in the interior of the component.

8. The method of any one of claims 1 to 7, further comprising: centering the ultrasonic source at least one of externally and relatively to the component using one or more spacers.

9. A method for the manufacture of a material deposition source, comprising: cleaning one or more components of the material deposition source by inserting an ultrasonic source into an interior of the one or more components; and assembling the material deposition source using the one or more components.

10. An apparatus for cleaning a component of a material deposition source, comprising: a tank configured to accommodate the component; and an ultrasonic source configured to be inserted into an interior of the component.

11. The apparatus of claim 10, further comprising another ultrasonic source inside or outside the tank, wherein the other ultrasonic source is configured to clean the component from the outside.

12. The apparatus of claim 10 or 11, wherein the tank is configured to accommodate at least one of a distribution pipe and an evaporation crucible of the material deposition source.

13. The apparatus of any one of claims 10 to 12, wherein the tank has a height of at least lm.

14. The apparatus of any one of claims 10 to 13, wherein the ultrasonic source is a sonotrode having a length of at least lm and/or a diameter in the range between 10mm and 50mm.

15. The apparatus any one of claim 10 to 14, further comprising a controller configured to perform the method of any one of claims 1 to 8.