WO2019240802A1

WO2019240802A1 - Evaporator for depositing material on a substrate, method of forming an evaporator, and evaporation apparatus for depositing material on a flexible substrate

Info

Publication number: WO2019240802A1
Application number: PCT/US2018/037617
Authority: WO
Inventors: Aki HOSOKAWA; Mark TRAN
Original assignee: Applied Materials, Inc.
Priority date: 2018-06-14
Filing date: 2018-06-14
Publication date: 2019-12-19
Also published as: TW202016329A; CN112368813A

Abstract

An evaporator for depositing at least one material on a substrate, the evaporator having at least one longitudinal element, the at least one longitudinal element comprising a front side and a back side; the front side being configured to receive the material to be evaporated; and the back side being opposite the front side and being at least partially coated with at least one thermal insulating material.

Description

EVAPORATOR FOR DEPOSITING MATERIAL ON A SUBSTRATE, METHOD OF FORMING AN EVAPORATOR, AND EVAPORATION APPARATUS FOR

DEPOSITING MATERIAL ON A FLEXIBLE SUBSTRATE

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to an evaporator for depositing material on a substrate, and a method of forming an evaporator for depositing material on a substrate. Embodiments of the present disclosure relate to an evaporation apparatus for depositing material on a (flexible) substrate, particularly an evaporation apparatus including an evaporator for depositing material on a substrate.

BACKGROUND

[0002] Depositing thin layers on a flexible substrate is a production process for many applications. Hie flexible substrates are coated in one or more chambers of a flexible substrate coating apparatus. The flexible substrates, such as foils made of plastics or pre-coated papers, are guided on rolls or drums and pass in this way the source of deposition material. Possible applications of the coated substrate range from providing coated foils for the packaging industry to depositing thin films for flexible electronics and advanced technology applications, such as smartphones, flat screen TVs and solar panels.

[0003] Different deposition processes may be used to achieve a layer with tire desired properties. For instance, in a thermal evaporation process, thin layers of aluminum are metallized onto flexible substrates. Substrates coated in such a way may for instance be used for the production of protective packaging or decorative materials. In further processes, such as in reactive coating processes, gas is supplied to the substrate additionally to an evaporated material from the material source in order to provoke a chemical reaction influencing the layer deposited on the substrate. By using such processes, several characteristics of the substrate may be controlled, such as barrier characteristics for water vapor or oxygen, and transparency characteri stics of the finished product.

[0004] However, these techniques for material deposition are usually energy consuming. For instance, in a thermal evaporation process, evaporators are usually made of ceramics that are highly energy-consuming. [0005] In light of the above, improved evaporators for depositing material on a substrate, improved evaporation sources for depositing material on a substrate and improved deposition apparatuses for depositing material on a substrate that overcome the problems described herem would be beneficial. Embodiments of tire present disclosure aim at providing evaporators, a method of forming evaporators, and evaporation apparatuses that overcome at least some of the problems in the art.

[0006] In light of the above, improved evaporators, a method of forming an improved evaporator, and improved evaporation apparatuses are provided. Further aspects and embodiments of the present disclosure are apparent from the dependent claims, the description, and the accompanying drawings; advantages and features of the present disclosure are apparent from the dependent claims, the description, and the accompanying drawings.

[0007] According to an aspect of the present disclosure, an evaporator for depositing material on a substrate is provided. The evaporator includes at least one longitudinal element having a front side and a back side. Further, the front side is configured to receive the material to be evaporated. Additionally, the back side is opposite the front side and is at least partially coated with at least one thennal insulating material.

[0008] According to a further aspect of the present disclosure, the at least one thermal insulating material is made of at least one material selected from the group consisting of W, Cr, Mo, Ni, Si, and alloys thereof, e.g. NiCr.

[0009] According to yet another aspect of the present disclosure, a method of forming an evaporator for depositing material on a substrate is provided. The method of forming an evaporator has at least one longitudinal element including a front side and a back side. Further, this method includes at least partially coating the back side with the at least one thermal insulating material. Particularly, the at least one thennal insulating material has at least one of an emissivity lower than 0.8, particularly ranging from 0.05 to 0.3, and a thermal conductivity lower than 173 W/m*K, particularly ranging from 13 to 95 W/m*K.

7 [0010] According to yet another aspect of the present disclosure, an evaporation apparatus for depositing material on a flexible substrate supported by a processing drum is provided. The evaporation apparatus includes a first set of evaporators as described herein, aligned in a first line along a first direction for generating a cloud of evaporated material to be deposited on the flexible substrate. Further, the evaporation apparatus includes a gas supply pipe extending in the first direction and being arranged between an evaporator of the first set of evaporators and the processing drum. Additionally, the gas supply pipe includes a plurality of outlets for providing a gas supply directed into the cloud of evaporated material and a position of the plurality of outlets is adjustable for changing a position of the gas supply directed into the cloud of evaporated material.

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 present 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. 1A shows a schematic cross sectional view illustrating an evaporation crucible for depositing material on a substrate according to embodiments described herein;

FIG. IB shows a schematic cross sectional view illustrating an evaporation crucible for depositing material on a substrate according to embodiments described herein;

FIG. 1C shows a schematic cross sectional view illustrating an evaporator boat for depositing material on a substrate according to embodiments described herein;

FIG. ID show's a schematic cross sectional view illustrating an evaporator boat for depositing material on a substrate according to embodiments described herein;

FIG. IE shows a schematic cross sectional view illustrating an evaporator boat for depositing material on a substrate according to embodiments described herein, the evaporator boat including at least two thermal insulating material coated sides;

FIG. IF show's a schematic cross sectional view of an evaporator boat according to embodiments described herein, the evaporator boat being entirely coated on the outer surface:

FIG. 1G shows a schematic cross sectional view' of an evaporator boat according to embodiments described herein, having a first coated layer and a second coated layer;

FIG. 2 shows a schematic top view of an evaporation apparatus according to embodiments described herein;

FIG. 3 show's a schematic front view of the evaporation apparatus showm in FIG. 2;

FIG. 4 show's a schematic side view' of the evaporation apparatus shown in FIG. 2;

FIG. 5 show's a schematic top view' of an evaporation apparatus according to embodiments described herein;

FIG. 6 shows a schematic front view of the evaporation apparatus shown in FIG. 5;

FIG. 7 show's a schematic front view' of the evaporation apparatus according to embodiments described herein;

FIG. 8 show's a schematic view' of the evaporation apparatus according to embodiments described herein;

[0001] Reference will now be made in detail to the various embodiments of the disclosure. one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. In the following, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0002] Before the embodiments of the present disclosure are described in more detail in the following, some terms and expressions used herein are explained.

[0003] In the present disclosure, the term“evaporator” can be understood as including at least one longitudinal element having a front side and a back side, and the front side being configured to receive material for evaporation. An “evaporator” can be understood as encompassing at least one of an evaporator boat and an evaporation crucible.

[0004] In the present disclosure, the term“evaporation crucible” or“crucible” can be understood as a reservoir for the material to be evaporated by heating the evaporation crucible. More specifically, an evaporation crucible as described herein may be equipped with a material supply for delivering the material to be evaporated to the crucibles. For example, the material to be evaporated may be supplied to the evaporation crucible in the form of a wire which may be melted by the evaporation crucible as described herein. Accordingly, the crucibles described herein may be configured for heating the material delivered to the crucibles to the melting and further to the evaporation temperature of the respective material to be evaporated.

[0005] In the present disclosure, the term“evaporator boat” can be understood as an evaporator that can have a“boat” shape.

[0006] According to some embodiments of the present disclosure, an evaporator boat can be understood as being provided with a recess forming a bottom and four sides. Accordingly, the bottom of the evaporator boat may correspond to the at least one longitudinal element as described herein, wherein the front side corresponds to the inner side of the“boat”, i.e. configured to receive the material to be evaporated, and the back side corresponds to the opposite side, i.e. the outer side of the“boat”.

[0007] According to embodiments combinahle with embodiments described herein, an evaporator boat may have a curved-shape, e.g. a banana shape, at least along a longitudinal direction. In this case, the bottom can correspond to the at least one longitudinal element exhibiting a curved shape, at least to some extent along the longitudinal direction, and at least one portion protruding upward from the bottom may be considered as a side of the banana- shaped evaporator boat.

[0008 ] In die present disclosure, a distinction between an“evaporation crucible"’ and an “e vaporator boat” can be provided, particularly m light of the material to be evaporated. An “evaporator boat” as described herein may be suitable for, particularly configured to, evaporate metal-based materials, e.g , aluminum (Al). An“evaporation crucible” as described herein may be suitable for, particularly configured to, evaporate at least one of organic and inorganic -based materials .

[0009] In the following, the term“evaporator” can be understood as referring to either an evaporation crucible or an evaporator boat as described herein.

[0010] In the present disclosure, a“flexible substrate” may be understood as a substrate that is bendable. In particular, a flexible substrate as referred to herein may be understood as a substrate suitable for being coated in an evaporation apparatus, in particular in a reactive evaporation apparatus. For example, the flexible substrate may be a foil or a web, e.g. foil or a web made of or containing plastics and polymers (such as polypropylene, PET substrates, substrates made of or containing OPP, BOPP, CPP, PE, LDPE, HOPE, OPA, PET), pre coated paper, or biodegradable films (such as PEA).

100111 In the present disclosure, the term“processing drum” may be understood as a roller which is used during processing of a flexible substrate as described herein. In particular, a“processing drum” may be understood as a roller which is configured to support a flexible substrate during processing. More specifically, the processing drum as described herein may be arranged and configured such that the flexible substrate, e.g. a foil or a web, may be wound around at least a part of the processing drum. For instance, during processing, the flexible substrate can be in contact with at least a lower portion of the processing drum. In other words, during processing, the flexible substrate may be wound around the processing drum such that the flexible substrate can be m contact with a lower portion of the processing drum and the flexible substrate can be provided below the processing dram.

[0012] In the present disclosure, a“gas supply pipe” may be understood as a pipe arranged and configured for providing a gas supply into a space between an evaporation crucible, particularly a set of evaporation crucibles, and a processing drum. For instance, the gas supply pipe may be positioned and/or shaped so as to direct a gas supply into a cloud of evaporated material between a first set of evaporation crucibles and the processing drum. The gas supply pipe can include openings or outlets which are arranged and configured such that the gas supply from the gas supply pipe can be directed into the cloud of evaporated material. For instance, the openings or outlets may have at least one shape selected from the group consisting of a circular shape, a rectangular shape, an oval shape, a ring-like shape, a triangular-like shape, a polygon-like shape, or any shape suitable for delivering gas into the cloud of evaporated material.

[0013] According to some embodiments as described herein, an evaporator for depositing at least one material on a substrate is provided. The evaporator has at least one longitudinal element that includes a front side and a back side, the front side being configured to receive material to be evaporated, and the back side being opposite the front side and being at least partially coated with at least one thermal insulating material.

[0014] In the present disclosure, the term“at least one longitudinal element” having a front side 13 and a back side 14 can be understood as referring to at least one of an evaporation crucible and the“bottom” of an evaporator boat.

[0015] FIG 1A shows a schematic cross sectional view of an evaporation crucible for depositing at least one material on a substrate according to embodiments described herein. As exempiarily shown in FIG. 1A, the evaporation crucible 10A can have at least one longitudinal element 12 that includes a front side 13 and a back side 14. Additionally, the front side 13 can be configured to receive material to be evaporated and the back side 14 opposite the front side 13 and can be at least partially coated with at least one thermal insulating material 15.

[0016] FIG. IB shows a schematic cross sectional view of an evaporation crucible for depositing at least one material on a substrate according to embodiments described herein. As exempiarily shown in FIG. IB, the evaporation crucible 10B can include at least one longitudinal element 12, the backside 14 of which may be coated entirely with at least one thermal insulating material 15.

[0017] In embodiments that can be combined with embodiments described herein, the at least one longitudinal element of the evaporation crucible can be covered with two or more layers of the at least one insulating material. In some embodiments, the two or more layers can be made of different thermal insulating material . Further, the two or more layers may have at least one of different thickness and identical thickness. Additionally, the two or more layers may at least one of partially cover the at least one longitudinal element and fully co ver the at least longitudinal element.

[0018] FIG. 1C shows a schematic cross sectional view of an evaporator boat for depositing at least one material on a substrate according to embodiments described herein. As exemplarily shown in FIG. 1C, the evaporator boat 20A can have at least one longitudinal element 21 that includes a front side 22 and a back side 23. Accordingly, the at least one longitudinal element 21 can particularly correspond to the“bottom” of the evaporator boat. Additionally, the front side 22 can be configured to receive material to be evaporated and the back side 23 opposite the front side 22 can be at least partially coated with at least one thermal insulating material 15. Additionally, the evaporator boat 20A can include four sides 24a, 24b, 24c (not shown), 24d (not shown), each having an“inner” surface and an“outer” surface. Particularly, at least one of the outer surface of one of the four sides 24a, 24b, 24c , 24d may be at least partially coated with the at least one thermal insulating material 15.

[GO 19 ] FIG. ID show's the evaporator boat 20B according to embodiments described herein, the back side 23 may be entirely coated with the at least one thermal insulating material 15. In other words, the back side 14 surface may be entirely covered by a layer of the at least one thermal insulating material 15 (not shown)

[0020] Generally, and not limited to the embodiment of Fig. I D, the layer of the at least one thermal insulating material may have a thickness greater than 0.1 pm and/or lower than 100 pm, particularly ranging from 0.5 pm to 10 pm.

[0021 ] In further embodiments, the back side 14 surface can be partially coated with the at least one thermal insulating material 15, particularly up to 80 % of the back side 14 surface may be coated with the at least one thermal insulating material 15

[0022] FIG. IE shows the evaporator boat 20C according to embodiments described herein, the outer surface of the four sides 24a, 24b, 24c (not shown), 24d (not shown) may be coated at least partially with the at least one thermal insulating material 15.

[0023] FIG. IF shows the evaporator boat 20D according to embodiments described herein, the evaporator boat 20D can be entirely coated with the at least one thermal insulating material 15 on the outer surface, particularly on the back side 23 of the at least one longitudinal element 21, and the outer side of at least one of the four sides 24a, 24b, 24c (not shown), 24d (not shown), particularly the outer surface of the four sides. In other words, the evaporation boat 2GD can be covered entirely with a layer of the at least one thermal insulating material 15, particularly the back side 23 and the outer surface of the four outer sides.

[0024] FIG. 1G shows an evaporator boat 20E according to embodiments as described herein. The evaporator boat 20E can be covered by two or more layers of the at least one insulating material 15. As exemplarily shown in FIG. 1G, a first layer 50 and a second layer 60 can cover entirely the back side 23 and the four sides 24a, 24b, 24c (not shown), 2.4d (not shown) respectively. In some embodiments, at least one of the first layer 50 and the second layer 60 may partially cover the back side 23 and / or the four sides 24a, 24b, 24c (not shown), 24d (not shown). The first layer 50 and the second layer 60 may be made of at least two different thermal insulating materials as described herein. Further, the first layer and the second layer 60 may have at least one of identical thickness and different thickness.

[0025] The front side of the at least one longitudinal element is typically not coated with the at least one insulating material. In particular, the evaporation crucible may include one longitudinal element having a front side and a back side, the back side being exclusively coated with the at least one thermal insulating material.

[0026] In the present disclosure, the term“thermal insulating material” can be understood as any material suitable for, particularly configured to, at least reduce at least one of heat consumption of an evaporator and heat loss from an evaporator, particularly heat loss from an evaporator towards the environment. For instance, a thermal insulating material can be understood as any material suitable for acting as a heat shield resulting in heat storage within an evaporator. For instance, the term“thermal insulating material” can refer to any material suitable for, e.g. configured to “hold” the heat generated in the evaporator within the evaporator, particularly during operation of tire evaporator. The“thermal insulating material” can encompass any material having at least one of low thermal emissivity and low thermal conductivity.

[0027] In light of the above, providing an evaporator having at least one longitudinal element, the back side of which can be coated with at least one thermal insulating material, beneficially overcomes the problems mentioned above. Particularly, an evaporator as described herein can beneficially provide heat consumption reduction, particularly heat loss reduction towards the environment

[0028] in embodiments that can combined with embodiments described herein, the at least one thermal insulating material 15 can be made of at least one of low emissivity material and low thermal conduction material .

[0029] In embodiments combinable with embodiments described herein, the at least one thermal insulating material can have an emissivity lower than 0.8, particularly ranging from 0.05 to 0.3, more particularly ranging from 0.1 to 0.2.

[0030] In further embodiments combinable with embodiments described herein, the at least one thermal insulating material may have a thermal conductivity lower than l73 W/m*K, particularly ranging from 13 to 147 W/m*K, more particularly ranging from 13 to 86 W/m*K.

[0031 In embodiments that can be combined with embodiments described herein, the at least one thermal insulating material 15 can be made of at least one material selected from the group consisting of W, Cr, Mo, Ni and alloys thereof, e.g. NiCr. The evaporator can be made of at least one of high emissive material and high thermal conduction material.

[0032] According to embodiments described herein, the evaporator may be made of material having an emissivity above 0.8, particularly ranging from 0.8 to 1. Accordingly, the evaporator may be made of at least one highly emissive ceramic material selected from the group consisting of ceramic, e.g. shiny ceramic and / or any electrically conductive ceramic, e.g boron nitride, titanium di-bororide.

[0033] in embodiments that can be combined with embodiments described herein, the evaporator may be made of material having a thermal conductivity above 86 W/K*m, particularly ranging from 86 to 104 W/K*m.

[0034] In further embodiments, the at least one longitudinal element 12 can be suitable for, i.e. configured to be at least one of electrically-heated, magnetically-heated and mechanically-heated

[0035] A method (not sliowm) of forming an evaporator has at least one longitudinal element including a front side and a back side according to embodiments as described herein. The method includes at least partially coating the back side with at least one thermal insulating material, particularly the at least one thermal insulating material as described herein.

[0036] In further embodiments that can be combined with embodiments described herein, coating the back side of the at least one longitudinal element can be performed by common CVD or PVD techniques, by evaporation, particularly by sputtering.

[0037] In some embodiments, coating of the back side of the at least one longitudinal element can be carried out partially, particularly over a surface area that is essentially identical to the surface of the front side configured to evaporate material.

[0038] In further embodiments, coating of the back side of the at least one longitudinal element may be carried out over the entire surface. In other words, the back side of the longitudinal element may be entirely covered by a layer of the at least one thermal insulating material. In this case, coating may be carried out so that the layer reaches a thickness greater than 0.1 pm and/or lower than 100 pm, particularly ranging from 0.5 to 10 pm.

[0039] In embodiments that can be combined with embodiments described herein, the method of forming an evaporator as described herein, coating can include a first coating with a first thermal insulating material and a second coating with a second thermal insulating material, the second thermal insulating material being different from the first thermal insulating material.

[0040] In some embodiments of the present disclosure, coating can include one or more coatings, each subsequent coating of the one or more coatings can be carried out with a different thermal insulating material. By providing a method of forming an evaporator having a back side covered with one or more thermally insulated layers, the evaporator can be further improved, particularly in terms of heat loss.

[0041] FIGS. 2 to 4 show' an evaporation apparatus 100 according to embodiments described herein for depositing material on a flexible substrate 160 supported by a processing drum 170.

[0042] In particular, as exemplarily shown in FIGS. 2 and 3, according to embodiments which can be combined with any embodiments described herein, the evaporation apparatus 100 includes a first set 110 of evaporators as described herein, e.g. evaporation crucibles as described herein, aligned in a first line 120 along a first direction, e.g. along the x~ direction shown in FIG. 2, for generating a cloud 151 of e vaporated material to be deposited on the flexible substrate 160. With exemplary reference to FIG. 2, the flexible substrate 160 can move in the y-direction during tire deposition process. The first set 110 of evaporation crucibles shown in FIG. 2 exemplarily can include crucibles 111 to 117. Further, as exemplarily shown in FIG. 4, the evaporation apparatus 100 can include a gas supply pipe 130 extending in the first direction and being arranged between the first set 110 of evaporation crucibles and the processing drum 170. As exemplarily shown in FIG. 4, the gas supply pipe 130 can include a plurality of outlets 133 for providing a gas supply directed into the cloud 151 of evaporated material. Further, as indicated by the double arrows in FIG. 3, the evaporation apparatus can be configured such that a position of the plurality of outlets is adjustable for changing a position of the gas supply directed into the cloud of evaporated material.

[0043] For instance, according to embodiments which can be combined with embodiments described herein, the evaporation apparatus 100 may be configured such that the position of the gas supply directed into the cloud 151 of evaporated material may be changed within the z-y-plane, as exemplarily shown in FIG. 3. Alternatively, the position of the gas supply directed into the cloud of evaporated material may also be changed by a rotation of the gas supply around the first direction, e.g. the x-direction shown in FIG. 3, such that the radial position of the outlets for providing the gas supply can be changed.

[0044] In the present disclosure, the expression“a position of the plurality of outlets is adjustable for changing a position of the gas supply” may be understood in that the evaporation apparatus can be configured such that at least two different positions of the gas supply provided through the outlets can be realized. For instance, the evaporation apparatus may include a fixation arrangement configured for fixing a first position of the gas supply pipe and for fixing a second position of the gas supply pipe winch is different from the first position. In particular, the at least two different positions can he located between the processing drum and the evaporation crucibles, as exemplarily described with reference to FIGS. 6 and 7. For example, the fixation arrangement may include two or more releasable connections, e.g. screw connections, winch can be provided at two or more different preselected positions. Accordingly, it may be understood that the position of the gas supply directed into the cloud of evaporated material may be adjusted by remounting the gas supply pipe from a first position to two or more preselected positions which are different from the first position. Additionally or alternatively, the position of the gas supply directed into the cloud of evaporated material may be adjusted by rotating the supply pipe around the longitudinal axis of the supply pipe from a first radial position to a second radial position, such that in the second radial position the outlets are provided at a different position than in the first radial position.

[0045 ] Additionally or alternatively, the fixation arrangement may include one or more elongated holes in which a fixation element of the gas supply pipe can be guided and fixed in order to change and adjust various positions of the gas supply pipe. Accordingly, according to embodiments which can be combined with embodiments described herein, the evaporation apparatus may include a fixation arrangement which can be configured for providing at least two different positions for fixation of the gas supply pipe, such that the gas supply directed into the cloud of evaporated material may be changed, e.g. by rotation of the gas supply pipe around the longitudinal axis of the gas supply pipe or translation of the gas supply pipe within the z-y -plane as exemplarily described with reference to FIG. 3.

[0046] Furthermore, a set of crucibles as referred to herein can be understood as a set of at least two crucibles. In particular, a set of crucibles may he described as being at least two crucibles aligned in a line. For instance, the line along which the crucibles of a crucible set can be aligned may run through the center of tire crucibles. In particular, the center of a crucible may be defined as tire geometrical center of the crucible in the x-direction and in the y-direetion, e.g. a center in the length and width direction of the crucible, as exemplarily shown in FIG. 2. According to further embodiments, the center of a crucible may be defined as being the center of gravity of the crucible.

[0047] In one embodiment, the crucibles in a set of crucibles may be of the same type or have substantially the same size. While not shown in the schematic views of the figures, the crucibles described herein may be equipped with a material supply for delivering the material to be evaporated by the crucibles to the crucibles. Further, the crucibles described herein may be configured for heating the material delivered to the crucibles to the melting and further to the evaporation temperature.

[0048] According to some embodiments, a crucible as described herein may also be comprised of an evaporator boat. For instance, an evaporator boat may include in one frame an arrangement of crucibles. In the embodiments described herein, a set of crucibles may for instance also be a set of evaporator boats. In one example, a set of evaporator boats may include two evaporator boats being arranged along a line. According to some embodiments, the term“crucible” can be synonymously used for the term“evaporation crucible.”

[0049] With exemplary reference to FIGS. 2 to 4, according to embodiments which can be combined with embodiments described herein, the first line 120 of the first set 1 10 of evaporation crucibles can be defined through the center of at least two of the crucibles in the first set of crucibles and the position of the gas supply is adjustable in a second direction being different from the first direction. For example, the second direction can be any direction in the z- -plane, as exemp!arily shown in FIG. 3. According to an embodiment which can be combined with embodiments described herein, the second direction may be perpendicular to the first line 120. More specifically, the second direction can be a horizontal direction, such as the y-direction shown in FIG. 3. The y-direction shown in FIG. 3 can correspond to the substrate transport direction. Accordingly, according to embodiments described herein, the position of the gas supply can be adjustable with respect to the first line 120 along which the first set 110 of aligned evaporation crucibles are positioned. In the front view of FIG. 3, the first line 120 along wfrich the first set 110 of evaporation crucibles can be aligned is indicated by a cross.

[0050 ] During processing, the flexible substrate 160 can be subjected to the material evaporated by tire first set 110 of evaporation crucibles as indicated by the cloud 151 of evaporated material, as exemplarily shown in FIG. 3. Further, during processing, a gas supply can be directed into the cloud 151 of evaporated material through a plurality of outlets 133 of the gas supply pipe 130, such that a portion of the evaporated material may react with the supplied gas. Accordingly, the flexible substrate 160 can be further subjected to evaporated material which has been reacted with the supplied gas such that during processing, the flexible substrate 160 can be coated with a layer including the material evaporated by the crucibles and the gas supplied by the gas supply pipe., e.g. in the form of reactive products of the components provided by the crucible and the gas supply pipe.

[0051] According to embodiments which can be combined with embodiments described herein, the evaporation apparatus may further include a positioning device 135, as exemplarily shown in FIG. 4. In particular, the positioning device 135 can be configured for adjusting the position of the gas supply pipe 130 for adjusting the position of the gas supply directed into the cloud of e vaporated material. For instance, tire positioning device 135 may be configured to move the gas supply pipe in any direction w ithin the y-z-plane, as exemplarily shown in FIG. 3. Additionally or alternatively, the positioning device 135 may be configured such that the gas supply pipe may be rotated around the longitudinal axis of the gas supply pipe, e.g. extending in the x-direction, such that the radial position of the outlets provided in the supply pipe may be adjusted such that a position of the gas supply directed into the cloud of evaporated material through the outlets can be changed. Accordingly, by providing an evaporation apparatus having a positioning device 135 as described herein, the position of the gas directed into the cloud of evaporated material can be adjusted, which may be beneficial for controlling and adjusting the properties of a gradient layer as described herein. In particular, the positioning device 135 may include a fixation arrangement as described herein.

[0052] According to embodiments which can be combined with embodiments described herein, the positioning device may include a positioning mechanism which can be configured for positioning the supply pipe within a plane perpendicular to the longitudinal extension of the supply pipe. Additionally or alternatively, the positioning mechanism may be configured for rotating the supply pipe around the longitudinal axis of the supply pipe. Hie positioning mechanism can be a manual mechanism or a powered mechanism, e.g. an electrically driven mechanism for example by employing electric actuators.

[0053] In particular, according to embodiments which can be combined with embodiments described herein, the position of the gas supply can be adjustable within a plane being perpendicular to the first direction ^"fire position of the gas supply can be adjustable within a positioning range of ± 80 mm relative to an initial position of the gas supply pipe, particularly within a positioning range of ± 60 mm, more particularly within a positioning range of ± 40 mm. Accordingly, the position of the gas supply may be adjustable with respect to an initial position within a radius of 0 mm - 80 mm, particularly within a radius of 0 mm- 60 mm, more particularly within a radius of 0 mm - 40 mm. For example, the initial position may be a first position as described herein. In particular, with exemplary' reference to FIG. 4, the positioning range may be a positioning area in the z-y-plane perpendicular to the x- direction, i.e. the longitudinal extension of the supply pipe. Accordingly, the positioning range may be a range in the y-direction and/or the z-direction, exemp!arily shown m FIG. 4.

[0054] With exemplary reference to FIGS. 5 to 7, according to embodiments which can be combined with embodiments described herein, the evaporation apparatus may further include a second set 1 0 of evaporation crucibles aligned in a second line 190 along the first direction for generating a further cloud 152 of evaporated material to he deposited on the flexible substrate 160. Tire second line 190 of the second set 180 of evaporation crucibles can be defined through the center of at least two of tire crucibles in the second set 180 of crucibles.

13 The second set 180 of evaporation crucibles shown in FIG. 5 exemplariiy can include crucibles 181 to 183, the center indicated by crosses. The second line 190 can run through the centers of the crucibles 181, 182, and 183.

[0055] With exemplariiy reference to FIG. 5, according to embodiments which can be combined with embodiments described herein, the first line 120 and the second line 190 can be displaced with respect to each other, particularly horizontally displaced with respect to each other, in a direction substantially perpendicular to the first direction. For instance, the first line 120 and the second line 190 can be displaced to each other in a range of between 20 mm and 90 mm, particularly between 40 mm and about 80 mm, more particularly between about 60 mm and about 80 mm. According to some embodiments, the first line 120 and the second line 190 can be displaced to each other by equal to or more than 40 mm, particularly by equal to or more than 60 mm. As exemplariiy shown in FIGS. 5 to 7, the gas supply pipe 130 can be provided between the first set 110 of crucibles, e.g. crucibles 111 to 114, and the processing drum 170 supporting the flexible substrate 160. Although not explicitly shown in FIGS. 5 to 7, the exemplary' embodiments as described with reference to FIGS. 5 to 7 may also include a plurality of outlets 133 provided in tire gas supply pipe 130 as well as a positioning device as described with reference to FIGS. 2 to 4.

[0056] In the exemplary embodiment of FIG. 5, the first set 110 of crucibles can include four crucibles, and the second set 180 of crucibles can include three crucibles. However, the number of crucibles shown in the figures described herein is an example for the sake of a better overview. For instance, the number of crucibles in the first set of crucibles and the second set of crucibles may be the same in one embodiment. The number of crucibles, either in the first set of crucibles or in the second set of crucibles, or in both, may be between 2 and 20, more particularly between 2 and 15, and even more between 4 and 10. In one example, the first set of crucibles includes two crucibles and the second set of crucibles includes two crucibles. In a further example, the first set of evaporation crucibles and the second set of evaporation crucibles may each include seven crucibles.

[0057] In FIG 5, the first line 120, along which the first set 110 of crucibles is arranged, and the second line 190, along which the second set 180 of crucibles is arranged, are displaced from each other in a displacement direction, e.g the y-direction shown in FIG 5. For instance, the displacement direction may be substantially perpendicular to the first direction along which the first line and the second line run. For instance, the displacement of the first line to the second line may be in the range of between 20 mm and 130 mm, particularly between 40 mm and about 80 mm, more particularly between about 60 mm and about 80 mm.

[0058] In the embodiment shown in FIG. 5, the cmcibles 181 , 182, 183 of the second set 180 of cmcibles are also displaced in the first direction compared to the crucibles 1 1 1, 112, 1 13, 114 of the first set 110 of cmcibles. According to some embodiments, the displacement of the cmcibles of the first set of cmcibles compared to the second set of cmcibles in the first direction may be in the range of between 0 nun to about 80 mm, particularly between 0 mm and about 60 mm, more particularly between 0 mm and about 40 mm. Accordingly, a displacement of 0 mm between the crucibles of the first set of cmcibles and the second set of cmcibles leads to a situation in which the crucibles of the first set of crucibles and the crucibles of the second set of cmcibles are in contact with each other.

[0059] With exemplary reference to FIG. 7, according to embodiments which can be combined with any other embodiment described herein, the first line 120 along which the cmcibles of the first set 110 of cmcibles can be arranged and the second line 190 along which the cmcibles of the second set 180 of cmcibles may be displaced with respect to each other in a substantially vertical direction, e.g. the z-direction as exemp!arily shown in FIG. 7. For instance, the first line 120 and the second line 190 may be vertically displaced with respect to each other by a distance selected from a range between 0 mm to about 80 mm, particularly between 0 mm and about 60 mm, more particularly between 0 mm and about 40 mm.

[0060] in the embodiments shown in FIGS. 5 to 7, the cmcibles can be described as being arranged in a staggered manner due to the displacement of the first line and the second line in the displacement direction, e.g. the y-direction, and in particular due to the additional displacement of the cmcibles of the first set and the cmcibles of tire second set in the first direction e.g. the x-direction. it has been found that a staggered arrangement of the cmcibles may be beneficial for the production of high quality gradient layers, particularly with respect to the homogeneity of the optical appearance and the control of barrier properties.

[0061] According to embodiments which can be combined with any other embodiment described herein, the gas supply pipe can be adapted for ensuring an almost constant gas supply through the outlets along the first direction from the first outlet to the last outlet of the gas supply pipe. For instance, the size of the outlets may be adapted to the diameter of the gas supply pipes. For example, the outlet size may increase for an increasing pipe diameter. According to some embodiments, the gas supply pipe and the outlets may be configured to be used in a vacuum environment. In particular, the gas supply pipe and the outlets may be configured to deliver a constant gas supply over the width of the flexible substrate to be coated in the first direction under vacuum conditions.

[0062] According to embodiments which can be combined with any other embodiment described herein, the diameter of the gas supply pipe as described herein may be between 10 mm and 30 mm, particularly between 12 mm and 20 mm, more particularly between 12 mm and 18 nun. In some embodiments which can be combined with other embodiments described herein, the diameter of the outlets in the gas supply pipe may be between 0.5 mm and 1.5 mm, particularly between 0.6 mm and 1.2 mm, more particularly between 0.6 mm and 1.0 mm. In one example, the evaporation apparatus is adapted for coating substrates hav ing a width of up to 2450 mm, and includes a gas supply pipe having a diameter of 12 mm with a plurality of outlets having a diameter of 0.6 mm.

[0063] With exemplar} reference to FIG. 8, an evaporation system 400 is illustrated. In particular, according to embodiments which can be combined with embodiments described herein, the evaporation system 400 may include an evaporation apparatus according to embodiments described herein and an oil printing module 101 configured for printing a patterned oil layer on die flexible substrate. As exemplarily shown in FIG. 8, the oil printing module 101 may include one or more patterns, especially a pattern 166 of one or more triangles.

[0064] Accordingly, the substrate may he coated with a patterned oil layer having an essentially identical pattern 166 to that of the oil printing module 101. The one or more triangles can be at least one of oil-free and oil-coated. Further, the evaporation system 400 can include an evaporator 100, particularly an evaporation crucible as described herein, the evaporation crucible 100 may he configured to evaporate material on the oil-free areas of the substrate, more particularly to evaporate A1 on the oil-free pattern of the substrate

[0065] Further, as exemplarily shown in FIG. 8, the evaporation system 400 can include a supply dram 161 for providing the flexible substrate to be coated and a take-up drum 162 for storing the substrate after coating.

[0066] In light of the above, the present disclosure is directed to evaporators that beneficially provide energy efficient material deposition, particularly heat efficient material deposition. For instance, the evaporator according to embodiments described herein, can ensure a reduction in terms of heat loss towards the environment during operation. Further, the evaporator according to embodiments described herein can allow for less consumption in terms of energy during material deposition, particularly in terms of heat consumption. Additionally, the method according to embodiments described herein can beneficially provide with an energy efficient evaporator for material deposition.

[0067] The disclosure is also directed to an apparatus for carrying out the disclosed methods and including apparatus parts for performing each described method steps. These method steps may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or m any other manner. Furthermore, tire disclosure is also directed to methods by which the described apparatus operates. It includes method steps for carrying out every' function of the apparatus.

Claims

1. An evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) for depositing at least one material on a substrate, the evaporator (10A, 10B, 20 A, 20B, 20C)) having at least one longitudinal element (12, 21 ), the at least one longitudinal element ( 12, 21) comprising a front side (13, 22) and a hack side (14, 23); the front side (13, 22) being configured to receive the material to be evaporated; and the back side (14, 23) being opposite the front side (13, 22) and being at least partially coated with at least one thermal insulating material (15).

2. Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to claim 1, the front side (13, 22) is not coated with the at least one thermal insulating material (15).

3. Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to claim 1 or 2, the at least one thermal insulating material (15) being configured to at least reduce heat loss from the evaporator (10A, 10B, 20A, 20B, 20C).

4. Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to any of claims 1 to 3, the at least one thermal insulating material (15) being made of one or two of: low emissivity material, particularly material having an emissivity lower than 0.8, more particularly ranging from 0.05 to 0.3; and low thermal conduction material, particularly material having a thermal conductivity lower than 173 W/m*K, more particularly ranging from 13 to 147 W/m*K.

5 Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to any of claims 1 to 4, the at least one thermal insulating material (15) being made of at least one material selected from the group consisting of W, Cr, Mo, Ni and alloys thereof, e.g. NiCr.

6. Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to any of claims 1 to 5, the back side (14, 23) surface being entirely covered by a layer of the at least one thermal insulating material (15).

7. Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to any of claims 1 to 6, the at least one longitudinal element (12, 21) being selected from the group consisting of at least a crucible, the bottom of an evaporator boat.

8 Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to any of claims 1 to 7, wherein the evaporator (10) is made of ceramic, particularly made of high emissivity ceramic, more particularly made of ceramic having an emissivity greater than 0.8, especially ranging from 0 8 to 1 .

9. Evaporator (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to any of claims 1 to 8, the at least one longitudinal element (12, 21) being configured to be at least one of electrically-heated, magnetically-heated and mechanically-heated.

10. A method of forming an evaporator having at least one longitudinal element comprising a front side and a back side; the method comprising at least partially coating the back side (14) with at least one thermal insulating material.

1 1. Method according to claim 10, the at least one thermal insulating material having at least one of an emissivity lower than 0.8, particularly ranging from 0.05 to 0.3 and a thermal conductivity lower than 173 W/m*K, more particularly ranging from 13 to 147 W/m*K.

12. Method according to any of claims 10 to 11, the at least one thermal insulating material being made of at least one material selected from the group consisting ofW, Cr, Mo, Ni and alloys thereof, e.g. NiCr.

13. Method according to any of claims 10 to 12, wherein coating is carried out by PVD or CVD, by evaporation, particularly by sputtering.

14. Method according to any of claims 10 to 13, wherein coating of the back side is carried out over the entire back side surface.

15. An evaporation apparatus (100) for depositing material on a flexible substrate (160) supported by a processing drum (170), the evaporation apparatus comprising: a first set (1 10) of evaporators (10A, 10B, 20A, 20B, 20C, 20D, 20E) according to any of claims 1 to 8 aligned in a first line (120) along a first direction for generating a cloud (151) of evaporated material to be deposited on the flexible substrate (160); and

a gas supply pipe (130) extending in the first direction and being arranged between an evaporator of the first set (110) of evaporators and the processing dram (170),

wherein the gas supply pipe (130) comprises a plurality of outlets (133) for providing a gas supply directed into the cloud of e vaporated material, and

wherein a position of the plurality of outlets is adjustable for changing a position of the gas supply directed into the cloud of e vaporated material.