Evaporation boats for evaporating metals

Abstract

The present disclosure relates to an evaporation boat for evaporating metal and to use of the evaporation boat for evaporating a metal selected from the group consisting of aluminum, copper and silver.

Description

Technical Field

[0001] The present disclosure relates to evaporation boats for evaporating metals. Background Art

[0002] The most common method of coating flexible substrates such as polymer films or papers with metals is so-called vacuum web coating using physical vapor deposition techniques. Coated flexible substrates are used in a wide range of applications, such as food packaging, for decorative purposes and in the manufacture of capacitors.

[0003] In a vacuum web coater, the substrate to be coated passes over a cooled metal drum where it is exposed to metal vapor. As a result, the metal is deposited on the substrate in the form of a thin layer.

[0004] In order to generate the required constant metal vapor, a series of ceramic evaporation boats aligned across the width of the film to be coated are placed in a cooled copper clamp and passed through a direct current at typically 10 -4 The process is heated to a temperature of 1400°C-1550°C in a vacuum of 1000 mbar. The metal wire is continuously fed to the surface of the evaporation boat, where it melts and evaporates. The most common metal used in this process is aluminum. Ceramic evaporation boats are usually composed of a mixture of titanium diboride (TiB2) and boron nitride (BN), and aluminum nitride (AlN) is sometimes used. Typically, the evaporation boat is a prismatic body with a rectangular cross-sectional area, a length of about 120 mm to 150 mm, a width of 25 mm to 40 mm, and a height of 8 mm to 12 mm, with a cavity filled with the liquid metal to be evaporated on the upper side of the evaporation boat.

[0005] Most metallized films are used in the packaging industry to extend the shelf life of food products. Coating a plastic film with an aluminum layer improves the barrier properties of the substrate, such as impermeability to oxygen, aromatic substances, light, heat or moisture. The barrier properties of the coated film are comparable to aluminum foil, but the production costs are lower.

[0006] Defects in the metallized film, so-called pinholes, affect the barrier properties in an undesirable manner. It is therefore necessary to avoid pinholes as much as possible.

[0007] The productivity of the metallization process has become critical over the past few years. The combination of high web speeds and excellent barrier properties is a key factor.

[0008] DE 10 2008 016 619 B3 discloses an evaporation boat having a plurality of recesses in the evaporation surface, the opening in each recess having an area / perimeter ratio greater than or equal to 1.5 mm. The shape of the recesses may be, for example, circular, rectangular, triangular or elliptical. The main benefit of this evaporation boat is described as improved wetting of aluminum both longitudinally and transversely of the evaporation surface of the evaporation boat. A disadvantage of this evaporation boat is that it does not allow pinhole-free operation, i.e. operation with few or no pinholes.

[0009] EP 1 688 514 A1 discloses an evaporation boat having grooves in the chamber of the evaporation boat to improve the wetting of the liquid aluminum on the upper surface of the evaporation boat where the metal is evaporated. A disadvantage of this evaporation boat is that the wetting of the liquid aluminum in the chamber is uneven if the so-called wire feed point, i.e. the point where the aluminum wire hits the chamber, is not in the center of the chamber. Due to the uneven wetting, pinhole-free operation is not possible.

[0010] DE 10 2013 211 034 A1 discloses an evaporation boat having an inner cavity and an outer cavity on the upper side of the evaporation boat to avoid aluminum spilling into the copper clip. A disadvantage of this design is that it does not allow pinhole-free operation, i.e. operation with few or no pinholes. In addition, the small area of ​​the inner cavity limits the ability to evaporate large amounts of aluminum.

[0011] There remains a need for further improvements in evaporation boats for evaporating metals with a view to achieving good film quality, ie higher optical density and reduced pinholes, and higher metal evaporation rates, ie high web speeds, when operating evaporation boats.

[0012] As used herein, "a", "an", "the", "at least one", and "one or more" are used interchangeably. Adding the plural form "(s)" to a term means that the term shall include both the singular and the plural. The term "comprising" shall also include the terms "consisting essentially of" and "consisting of". Summary of the invention

[0013] In a first aspect, the present disclosure relates to an evaporation boat for evaporating metal, wherein the evaporation boat has an upper side, a lower side, two side surfaces and two clamping surfaces, and wherein the metal is evaporated from the upper side of the evaporation boat, and wherein the upper side of the evaporation boat comprises a cavity, and wherein the cavity has an outer contour at the upper side of the evaporation boat, and wherein the outer contour of the cavity has a shortest circumscribed contour, and wherein the outer contour has a circumferential length, and wherein the shortest circumscribed contour has a circumferential length, and wherein the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is less than 1, preferably at most 0.8.

[0014] On the other hand, the present disclosure relates to an evaporation boat for evaporating metal, wherein the evaporation boat has an upper side, a lower side, two side surfaces and two clamping surfaces, and wherein the metal is evaporated from the upper side of the evaporation boat, and wherein the upper side of the evaporation boat includes a cavity, and wherein the cavity of the evaporation boat includes a plurality of recesses in the upper side of the evaporation boat, and wherein each individual recess of the plurality of recesses has an outer contour at the upper side of the evaporation boat, and wherein the outer contour of each individual recess has a shortest circumscribed contour, and wherein the outer contour of each individual recess has a circumferential length, and wherein for at least one individual recess, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is less than 1, preferably at most 0.8.

[0015] In yet another aspect, the present disclosure relates to use of an evaporation boat as disclosed herein for evaporating a metal selected from the group consisting of aluminum, copper and silver.

[0016] With the evaporation boat disclosed herein, the tendency of liquid metal to overflow into the water-cooled copper clamp can be reduced. In addition, the area covered by the molten metal is maximized, and a smooth melting of the metal wire is achieved. In addition, the thickness of the liquid metal pool can be kept as thin as possible. Therefore, even for high evaporation rates, the occurrence of pinholes in the metallized film can be largely prevented. Another advantage of the evaporation boat disclosed herein is that power consumption is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present disclosure is explained in more detail on the basis of the accompanying drawings, in which:

[0018] Figures 1A to 1D Various views of a reference evaporation boat are shown;

[0019] FIG. 2A to FIG. 2F showing various views of an evaporation boat as disclosed herein;

[0020] FIG. 3A to FIG. 3F showing various views of an evaporation boat as disclosed herein;

[0021] 4A to 4F showing various views of an evaporation boat as disclosed herein;

[0022] Figure 4G to Figure 4J showing various views of an evaporation boat as disclosed herein;

[0023] FIG. 5A to FIG. 5E showing various views of an evaporation boat as disclosed herein;

[0024] FIG. 6A to FIG. 6E showing various views of an evaporation boat as disclosed herein;

[0025] 7A to 7E showing various views of an evaporation boat as disclosed herein;

[0026] Figures 8 to 12 shows the upper side of an evaporation boat as disclosed herein; and

[0027] FIG. 13A to FIG. 13D Various views of an evaporation boat as disclosed herein are shown. DETAILED DESCRIPTION

[0028] The evaporation boat as disclosed herein has an upper side, a lower side, two side surfaces and two clamping surfaces. The metal is evaporated from the upper side.

[0029] The upper side of the evaporation boat disclosed herein comprises a cavity. The cavity comprises a recess located in the upper side of the evaporation boat. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated.

[0030] The cavity of the evaporation boat has an outer contour at the upper side of the evaporation boat. The outer contour is in the same plane as the upper side of the evaporation boat outside the cavity.

[0031] The outer contour of the cavity has a shortest circumscribed contour. The shortest circumscribed contour is the shortest contour that circumscribes the outer contour, i.e., the contour that has the shortest length and circumscribes the outer contour. In other words, the shortest circumscribed contour is the shortest contour of the area that circumscribes the cavity, which cavity can have any possible shape. The outer contour has a circumferential length, and the shortest circumscribed contour has a circumferential length. For the evaporation boat disclosed herein, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is less than 1. This ratio being less than 1 means that the circumferential length of the shortest circumscribed contour of the outer contour of the cavity is less than the circumferential length of the outer contour of the cavity.

[0032] For standard shapes such as circles or regular polygons, the shortest circumscribed contour of the outer contours of these standard shapes corresponds to the outer contours of these standard shapes. For a standard evaporation boat with a rectangular cross-sectional area and a cavity with a rectangular outer contour, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is 1, because the outer contour corresponds to the shortest circumscribed contour.

[0033] The shortest circumscribed contour of the outer contour of the cavity of the evaporation boat disclosed herein can be, for example, a circle, a polygon (e.g., a rectangle), or a combination of a polygon and one or more curves or circular portions. In some embodiments, the shortest circumscribed contour of the outer contour of the cavity of the evaporation boat is a rectangle, or a rectangle with rounded corners, or a combination of a rectangle and two semicircles, i.e., a rectangle in which one semicircle replaces each of the two smaller sides of the rectangle.

[0034] Preferably, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is at most 0.8. In some embodiments, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is at most 0.75, or at most 0.70, or at most 0.65, or at most 0.60.

[0035] The ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour may be at least 0.1. In some embodiments, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is at least 0.2, or at least 0.35.

[0036] In some embodiments, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is at least 0.1 and at most 0.8. In some embodiments, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is at least 0.2 and at most 0.8. In some embodiments, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is at least 0.35 and at most 0.70.

[0037] The ratio of the area surrounded by the outer contour of the cavity to the total surface area of ​​the upper side of the evaporation boat is less than 1, preferably at most 0.95. The ratio of the area surrounded by the outer contour of the cavity to the total surface area of ​​the upper side of the evaporation boat may be at least 0.15. In some embodiments, the ratio of the area surrounded by the outer contour of the cavity to the total surface area of ​​the upper side of the evaporation boat may be at least 0.15 and at most 0.95.

[0038] The area surrounded by the outer contour of the cavity may include an area in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the cavity. Such an area with an upper side in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the cavity may also be referred to as an "island". In some embodiments, the area surrounded by the outer contour of the cavity does not include an area in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the cavity. In other words, for these embodiments, the area surrounded by the outer contour of the cavity does not include an island.

[0039] Preferably, the area surrounded by the outer contour of the chamber does not include an area in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the chamber, that is, the area surrounded by the outer contour of the chamber does not include an island.

[0040] In some embodiments of the evaporation boat disclosed herein, the cavity comprises a single recess located in the upper side of the evaporation boat, and the area surrounded by the outer contour of the cavity is a continuous area. "Single recess" means that there is only one recess filled with liquid metal to be evaporated on the upper side of the evaporation boat, and there are no other recesses on the upper side of the evaporation boat except the single recess. In some embodiments of the evaporation boat disclosed herein, the cavity consists of a single recess located in the upper side of the evaporation boat, and the area surrounded by the outer contour of the cavity is a continuous area.

[0041] In some embodiments of the evaporation boat disclosed herein, the cavity of the evaporation boat includes a plurality of recesses located in the upper side of the evaporation boat. Each individual recess of the plurality of recesses has an outer contour at the upper side of the evaporation boat. The outer contour of each individual recess has a shortest circumscribed contour. The outer contour of each individual recess has a circumferential length, and the shortest circumscribed contour of each individual recess has a circumferential length. For at least one individual recess, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is less than 1, preferably at most 0.8.

[0042] As used herein, "a plurality of recesses" means that there are at least two recesses in the upper side of the evaporation boat. There may also be three, four or five recesses in the upper side of the evaporation boat. There may also be more than five recesses in the upper side of the evaporation boat.

[0043] For at least one individual recess of the plurality of recesses, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour is less than 1, preferably at most 0.8. The ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour may be less than 1, preferably at most 0.8, and this is also true for more than one recess of the individual recesses of the plurality of recesses. The ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour may be less than 1, preferably at most 0.8, and this is also true for each individual recess of the plurality of recesses. For example, the cavity of the evaporation boat as disclosed herein may consist of 4 individual recesses. One of the four individual recesses may be positioned close to one of the two clamping zones of the evaporation boat, a second recess of the four individual recesses may be positioned close to the other of the two clamping zones, and the third and fourth individual recesses may be located in the central area of ​​the evaporation boat, i.e., in an area between the two recesses close to the clamping zone. The clamping zone of the evaporation boat is positioned close to the clamping surface of the evaporation boat. For one of the two separate recesses located close to one of the clamping zones, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour may be less than 1. Likewise, for the second recess located close to one of the two clamping zones, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour may be less than 1, preferably at most 0.8. For the other two recesses, the ratio of the circumferential length of the shortest circumscribed contour to the circumferential length of the outer contour may be 1, or may also be less than 1, preferably at most 0.8.

[0044] The evaporation boat has a longitudinal axis. The longitudinal axis is parallel to the side surface of the evaporation boat. The longitudinal axis is also parallel to the upper and lower sides of the evaporation boat. The cavity has a maximum width in a direction perpendicular to the longitudinal axis, and the cavity has a minimum width in a direction perpendicular to the longitudinal axis. The maximum width of the cavity and the minimum width of the cavity are measured in a plane on the upper side of the evaporation boat, that is, the upper side of the evaporation boat is measured in a plane outside the outer contour of the cavity. The minimum width of the cavity is generally less than the maximum width of the cavity. For an embodiment in which the cavity of the evaporation boat includes a single recess located in the upper side of the evaporation boat, the ratio of the minimum width of the cavity to the maximum width of the cavity may be at least 0.15. The ratio of the minimum width of the cavity to the maximum width of the cavity may also be at least 0.2, or at least 0.5.

[0045] The minimum width of the cavity in the direction perpendicular to the longitudinal axis is measured by determining the width of the cavity in the direction perpendicular to the longitudinal axis at each position of the cavity in the direction perpendicular to the longitudinal axis, wherein the minimum width among all measured widths is the minimum width of the cavity in the direction perpendicular to the longitudinal axis. "At each position of the cavity in the direction perpendicular to the longitudinal axis" means at a depression or recess on the upper side of each evaporation boat in the direction perpendicular to the longitudinal axis. The maximum width of the cavity in the direction perpendicular to the longitudinal axis is measured by determining the width of the cavity in the direction perpendicular to the longitudinal axis at each position of the cavity in the direction perpendicular to the longitudinal axis, wherein the maximum width among all measured widths is the maximum width of the cavity in the direction perpendicular to the longitudinal axis.

[0046] The minimum width of the cavity in the direction perpendicular to the longitudinal axis is at least 3 mm, preferably at least 5 mm, and more preferably at least 7 mm. In some embodiments, the minimum width of the cavity in the direction perpendicular to the longitudinal axis of the evaporation boat is at least 10 mm. In some embodiments, the minimum width of the cavity in the direction perpendicular to the longitudinal axis of the evaporation boat is half of the maximum width of the cavity minus 3 mm to 7 mm.

[0047] For embodiments in which the cavity of the evaporation boat includes a plurality of recesses in the upper side of the evaporation boat, the minimum width of the cavity and the maximum width of the cavity can be measured for each individual recess. The minimum width of the cavity is the minimum width of the individual values ​​of the minimum width of the individual recesses. The minimum width of the individual recesses is measured in a direction perpendicular to the longitudinal axis. The maximum width of the cavity is the maximum width of the individual values ​​of the maximum width of the individual recesses. The maximum width of the individual recesses is measured in a direction perpendicular to the longitudinal axis. The minimum width of the cavity is usually less than the maximum width of the cavity.

[0048] As described above, the cavity has a minimum width in a direction perpendicular to the longitudinal axis, and the cavity also has a minimum width in a direction parallel to the longitudinal axis. The minimum width of the cavity in a direction parallel to the longitudinal axis is measured by determining the width of the cavity in a direction parallel to the longitudinal axis at each position of the cavity in a direction parallel to the longitudinal axis, wherein the minimum width among all measured widths is the minimum width of the cavity in a direction parallel to the longitudinal axis.

[0049] The minimum width of the cavity in a direction parallel to the longitudinal axis is at least 3 mm, preferably at least 5 mm, more preferably at least 7 mm.

[0050] For embodiments in which the cavity of the evaporation boat includes a plurality of recesses in the upper side of the evaporation boat, the minimum width of the cavity and the maximum width of the cavity can be measured for each individual recess. The minimum width of the cavity is the minimum width of the individual values ​​of the minimum width of the individual recesses. The minimum width of the individual recesses is measured in a direction perpendicular to the longitudinal axis or in a direction parallel to the longitudinal axis, respectively. The maximum width of the cavity is the maximum width of the individual values ​​of the maximum width of the individual recesses. The maximum width of the individual recesses is measured in a direction perpendicular to the longitudinal axis. The minimum width of the cavity is usually smaller than the maximum width of the cavity.

[0051] In some embodiments, the cavity of the evaporation boat includes a single recess located in the upper side of the evaporation boat, and the area surrounded by the outer contour of the cavity is a continuous area, and the area surrounded by the outer contour of the cavity does not include an area in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the cavity, and the evaporation boat has a longitudinal axis, and the cavity has a minimum width in a direction perpendicular to the longitudinal axis, and the minimum width of the cavity in the direction perpendicular to the longitudinal axis is at least 3 mm, preferably at least 5 mm, and more preferably at least 7 mm.

[0052] The outer contour of the cavity of the evaporation boat disclosed herein includes a plurality of extensions pointing inwardly (i.e., toward the area surrounded by the outer contour). The plurality of extensions can also be regarded as extensions of the shortest circumscribed contour of the outer contour of the cavity, i.e., extensions extending inwardly (i.e., toward the area surrounded by the outer contour) from the shortest circumscribed contour of the outer contour. In other words, the plurality of extensions extending inwardly from the shortest circumscribed contour of the outer contour of the cavity are generated by extensions of the bulk material of the evaporation boat outside the outer contour of the cavity, which extensions point to the area surrounded by the outer contour. Due to these plurality of extensions of the outer contour, the shortest circumscribed contour of the outer contour has a circumferential length that is shorter than the circumferential length of the outer contour.

[0053] The evaporation boat disclosed herein may also be described as an evaporation boat for evaporating metal, wherein the evaporation boat has an upper side, a lower side, two side surfaces and two clamping surfaces, and wherein the metal is evaporated from the upper side of the evaporation boat, and wherein the upper side of the evaporation boat comprises a cavity, and wherein the cavity has an outer contour at the upper side of the evaporation boat, and wherein the outer contour of the cavity of the evaporation boat disclosed herein comprises a plurality of extensions pointing inwardly (i.e. towards the area enclosed by the outer contour). The description of the evaporation boat disclosed herein does not include the shortest circumscribed contour of the outer contour of the cavity. The shortest circumscribed contour is a theoretical contour for explanation purposes.

[0054] As used herein, "multiple extensions" means at least 2 extensions. The outer contour may include at least 4, at least 6, at least 8, at least 10, at least 12, at least 20, or at least 50 extensions. Typically, the outer contour includes at most 100 extensions.

[0055] Typically, the extension is positioned along a region of the shortest circumscribed contour of the cavity close to the two side surfaces of the evaporation boat. In some embodiments, the extension is also positioned along a region of the shortest circumscribed contour of the cavity close to the two clamping surfaces of the evaporation boat.

[0056] The extension may be positioned along the complete shortest circumscribed contour of the cavity. It is also possible that the extension may be positioned only along one or more portions of the shortest circumscribed contour.

[0057] The outer contour of the cavity may include lines of regular shapes, lines of irregular shapes, or combinations thereof. Lines of regular shapes are lines that include repetitions of a basic pattern. Typically, lines of regular shapes include at least three, at least four, or at least six repetitions of a basic pattern. The basic pattern of lines of regular shapes may include segments of circular lines, segments of polygonal lines, meandering lines, curves such as waveforms or sinusoidal lines, or combinations thereof. Lines of irregular shapes that do not have repetitions of a basic pattern and combinations of lines of irregular shapes with lines of regular shapes are also possible.

[0058] In some embodiments, the outer contour of the cavity is regularly shaped in the form of a corrugated contour. In some embodiments, the outer contour of the cavity is irregularly shaped with extensions of different shapes and sizes.

[0059] The cavity of the evaporation boat as disclosed herein has a bottom surface and a side surface along the outer contour of the cavity. Typically, the bottom surface of the cavity is parallel to the upper side of the evaporation boat. The side surface of the cavity extends from the outer contour of the cavity to the bottom surface of the cavity at the upper side of the evaporation boat. Typically, the side surface of the cavity is flat. The angle enclosed by the surface area of ​​the upper side of the evaporation boat outside the outer contour of the cavity and the side surface of the cavity may be 45° to 135°. In some embodiments, the angle enclosed by the surface area of ​​the upper side of the evaporation boat outside the cavity and the side surface is 90°. At the lower end of the side surface of the cavity adjacent to the bottom surface of the cavity, the transition from the side surface of the cavity to the bottom surface may be rounded, for example due to machining by milling. At the upper end of the side surface of the cavity, there may be a slope appropriately designed for the ceramic material of the evaporation boat.

[0060] In some embodiments, the side surface of the cavity is inclined upward from the bottom surface of the cavity to the outer contour of the cavity. The side surface of the cavity can be inclined upward with a curvature or in an irregular manner. The side surface of the cavity can be inclined upward only near the clamping area, or it can also be inclined upward in other areas of the cavity.

[0061] The cavity of the evaporation boat as disclosed herein has a certain depth. The depth of the cavity is the depth from the plane of the upper side of the evaporation boat outside the outer contour of the cavity to the bottom surface of the cavity, which is measured perpendicular to the plane of the upper side of the evaporation boat outside the outer contour of the cavity. The depth of the cavity is generally 0.5mm to 5mm, preferably 1mm to 3mm. The ratio of the depth of the cavity to the height of the evaporation boat can be 0.03 to 0.65, and preferably 0.05 to 0.3. The height of the evaporation boat is measured in the area outside the outer contour of the cavity.

[0062] The side surface of the cavity has a certain height. The height of the side surface of the cavity is measured perpendicular to the plane of the upper side of the evaporation boat outside the outer contour of the cavity. The height of the side surface of the cavity corresponds to the depth of the cavity and is generally 0.5 mm to 5 mm, preferably 1 mm to 3 mm.

[0063] Due to the inwardly directed extensions of the outer contour, the side surface of the cavity also comprises extensions of the side surface of the cavity.

[0064] In some embodiments of the evaporation boat disclosed herein, the bottom surface of the cavity is not parallel to the upper side of the evaporation boat, and the depth of the cavity may be different at different positions of the bottom surface of the cavity. For example, the depth of the cavity may be larger near the outer contour of the cavity, and may be smaller in the central area of ​​the cavity (i.e., at a position further away from the outer contour). It is possible that the depth of the cavity is, for example, 3 mm near the outer contour of the cavity, and the depth of the cavity is, for example, 1 mm or even 0 mm in the central area of ​​the cavity. The bottom surface of the cavity may also have several peaks and depressions. For example, the cavity may have a wavy bottom surface. The bottom surface of the cavity may also have peaks and depressions distributed in other regular patterns. The bottom surface of the cavity may also be a free surface with irregularly distributed peaks and depressions.

[0065] If the bottom surface is not parallel to the upper side of the evaporation boat, and the depth of the cavity is different at different positions of the bottom surface of the cavity, the depth of the cavity is measured at the position with the maximum depth, that is, the depth of the cavity should be understood as the maximum depth of the cavity. The depth of the cavity is generally 0.5 mm to 5 mm, preferably 1 mm to 3 mm, which is also true for the embodiment in which the bottom surface of the cavity is not parallel to the upper side of the evaporation boat.

[0066] In some embodiments of the evaporation boat disclosed herein, the cavity includes a recess and a central area located in the upper side of the evaporation boat. The recess is positioned along the outer contour of the cavity, and the central area is surrounded by the recess. The depth of the cavity measured at the position of the recess may be 0.5 mm to 5 mm, and is different from the depth of the cavity measured at the position of the central area. The depth of the cavity measured at the position of the central area may be 0 mm to 5 mm. If the depth of the cavity measured at the position of the recess is different at different positions of the recess, the depth of the cavity measured at the position of the recess is measured at the position with the maximum depth, that is, the depth of the cavity measured at the position of the recess should be understood as the maximum depth of the recess of the cavity. If the depth of the cavity measured at the position of the central area is different at different positions of the central area, the depth of the cavity measured at the position of the central area is measured at the position with the maximum depth, that is, the depth of the cavity measured at the position of the central area should be understood as the maximum depth of the central area of ​​the cavity.

[0067] In some embodiments of the evaporation boat disclosed herein, the cavity has a zigzag form. Preferably, the zigzag form has rounded corners. The outer contour of the zigzag cavity can be formed by segments of a circular line connected by straight lines. The outer contour of the zigzag cavity has the form of a zigzag line, preferably with rounded corners. Preferably, the zigzag line is along two side surfaces of the evaporation boat.

[0068] In some embodiments, the cavity has a zigzag form, preferably a zigzag form with rounded corners, and the evaporation boat has a longitudinal axis, and the cavity has a minimum width in a direction perpendicular to the longitudinal axis, and the minimum width of the cavity in a direction perpendicular to the longitudinal axis is at least 3 mm, preferably at least 5 mm, and more preferably at least 7 mm.

[0069] The outer contour of the cavity of the evaporation boat disclosed herein includes a plurality of extensions pointing inwardly. The plurality of extensions are extensions extending inwardly from the shortest circumscribed contour of the outer contour. Typically, the extensions are positioned along the region of the shortest circumscribed contour of the cavity close to the two side surfaces of the evaporation boat. The outer contour of the cavity may include at least four, preferably at least six, and more preferably at least eight extensions pointing inwardly. Half the number of extensions may be positioned along each of the two side surfaces of the evaporation boat.

[0070] The width of the extension in a direction parallel to the longitudinal axis of the evaporation boat is at least 1 mm. The width of the extension in a direction parallel to the longitudinal axis of the evaporation boat is at most 10 mm. In a direction parallel to the longitudinal axis of the evaporation boat, the distance between two adjacent extensions may be at least 2 mm, preferably at least 5 mm, and more preferably at least 7 mm. The distance between two adjacent extensions in a direction parallel to the longitudinal axis of the evaporation boat may be constant.

[0071] The length of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat is at least 1 mm, preferably at least 5 mm, more preferably at least 10 mm. The length of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat is at most the maximum width of the cavity minus 3 mm, preferably minus 5 mm, more preferably minus 10 mm. The length of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat is measured from the shortest circumscribed contour of the outer contour of the cavity to the end of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat. The length of individual extensions in the plurality of extensions may be the same for all extensions of the outer contour of the cavity, or may be different for individual extensions of the outer contour of the cavity. The average length of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat (i.e., the arithmetic mean of the lengths of the individual extensions) may be 10 to 90%, or 20 to 80%, or 30 to 70%, or 40 to 60% of the maximum width of the cavity. Preferably, the average length of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat is 30% to 70%, more preferably 40% to 60% of the maximum width of the cavity. In a preferred example, the average length of the extension in a direction perpendicular to the longitudinal axis of the evaporation boat is half the maximum width of the cavity.

[0072] Individual extensions of the plurality of extensions may have two or three or more different lengths. At least one, preferably at least two extensions have a length perpendicular to the longitudinal axis of the evaporation boat of at least 50%, preferably at least 60% of the maximum width of the chamber.

[0073] Preferably, there are three different lengths of the individual extensions of the outer contour of the cavity. The first length of the three different lengths of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat corresponds to 10% to 90% of the maximum width of the cavity. The second length of the three different lengths of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat corresponds to the first length of the three lengths minus 0.1mm to 10mm, preferably minus 3mm to 7mm. The third length of the three different lengths of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat corresponds to the first length of the three lengths plus 0.1mm to 10mm, preferably plus 3mm to 7mm. Preferably, the length difference between the first and second lengths of the three lengths is equal to the length difference between the first and third lengths of the three lengths. Preferably, the first, second and third lengths of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat are 12mm to 22mm, 7mm to 17mm and 17mm to 27mm, respectively.

[0074] The respective extensions of the outer contour of the cavity may be arranged in an alternating manner along the two side surfaces of the evaporation boat.

[0075] In some embodiments, the cavity of the evaporation boat includes a single recess located in the upper side of the evaporation boat, and the area surrounded by the outer contour of the cavity is a continuous area, and the area surrounded by the outer contour of the cavity does not include an area in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the cavity, and the evaporation boat has a longitudinal axis, and the cavity has a minimum width in a direction perpendicular to the longitudinal axis, and the minimum width of the cavity in the direction perpendicular to the longitudinal axis is at least 3 mm, preferably at least 5 mm, and more preferably at least 7 mm, and the outer contour of the cavity includes at least four extensions pointing inward, at least four extensions are extensions extending inward from the shortest circumscribed contour of the outer contour, and the width of the extension in a direction parallel to the longitudinal axis of the evaporation boat is at least 1 mm and at most 10 mm, and the length of the extension in a direction perpendicular to the longitudinal axis of the evaporation boat is at least 1 mm and at most the maximum width of the cavity minus 3 mm.

[0076] In some embodiments, the cavity of the evaporation boat has a zigzag form, preferably a zigzag form with rounded corners, and the cavity of the evaporation boat includes a single recess located in the upper side of the evaporation boat, and the area surrounded by the outer contour of the cavity is a continuous area, and the area surrounded by the outer contour of the cavity does not include an area in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the cavity, and the evaporation boat has a longitudinal axis, and the cavity has a minimum width in a direction perpendicular to the longitudinal axis, and the minimum width of the cavity in a direction perpendicular to the longitudinal axis is at least 3 mm, preferably at least 5 mm, and more preferably at least 7 mm, and the outer contour of the cavity includes at least four extensions pointing inward, at least four extensions are extensions extending inward from the shortest circumscribed contour of the outer contour, and the width of the extension in a direction parallel to the longitudinal axis of the evaporation boat is at least 1 mm and at most 10 mm, and the length of the extension in a direction perpendicular to the longitudinal axis of the evaporation boat is at least 1 mm and at most the maximum width of the cavity minus 3 mm.

[0077] The upper side of the evaporation boat may be point symmetrical relative to the center point of the upper side of the evaporation boat. In some embodiments, the upper side of the evaporation boat is point symmetrical relative to the center point of the upper side of the evaporation boat, and the upper side of the evaporation boat is not mirror symmetrical relative to the middle axis of the upper side of the evaporation boat.

[0078] In a preferred embodiment, the outer contour of the cavity has eight extensions with three different lengths in a direction perpendicular to the longitudinal axis of the evaporation boat, and the eight extensions are arranged in an alternating manner along the two side surfaces of the evaporation boat, and the upper side of the evaporation boat is point-symmetrical with respect to the center point of the upper side of the evaporation boat, and one extension with a second length among the three different lengths in the extensions is arranged adjacent to the center point of the upper side of the evaporation boat, and one extension with a third length among the three different lengths in the extensions is arranged adjacent to the extension adjacent to the center point, and two extensions with a first length among the three different lengths in the extensions are arranged at the ends of the cavity close to the clamping area.

[0079] For a standard evaporation boat known in the prior art with a standard cavity (i.e. a cavity whose circumferential length of the shortest circumscribed contour of the cavity is as long as the circumferential length of the outer contour of the cavity), the side surface of the cavity is the boundary of the molten metal. At the two longer sides of the cavity, the molten metal will not overflow from the side surface of the cavity to the upper side of the evaporation boat. For higher evaporation rates, there is a risk that the molten metal will overflow from the side surface of the cavity at the two smaller sides of the cavity near the clamping area.

[0080] For the evaporation boat as disclosed herein, the surface area of ​​the side surface of the cavity is greater than the side surface of the cavity of the standard evaporation boat. Compared with the standard evaporation boat, the surface area of ​​the side surface of the cavity is increased due to the extension of the outer contour of the cavity, that is, due to the increase in the circumferential length of the outer contour of the cavity compared with the standard evaporation boat. The increased side surface area of ​​the cavity of the evaporation boat as disclosed herein is an additional surface area where the molten metal can be evaporated. Therefore, the evaporation rate per unit area (e.g., the evaporation rate per square millimeter) is locally increased at the outer contour of the cavity due to the increase in the side surface of the cavity. The locally increased evaporation rate helps to guide or draw the molten metal from the wire feeding point (i.e., the point where the aluminum wire hits the cavity) to the side surface of the cavity, and exceeds the outer contour of the cavity, reaching the upper side of the evaporation boat outside the outer contour of the cavity. The side surface of the cavity is not the boundary of the molten metal, but the molten metal can overflow the outer contour of the cavity, and can also wet the upper surface of the evaporation boat outside the outer contour of the cavity. This can also be described as a "suction effect", which makes the area wetted by the molten metal wider. For the evaporation boat as disclosed herein, the wetted surface area is wider than the standard evaporation boat, that is, the wetted surface area is wider in the direction perpendicular to the longitudinal axis. Even if the bottom surface of the cavity is smaller than the standard cavity, the suction effect caused by the increased surface area of ​​the side surface of the cavity will also result in a wider area wetted by the molten metal. The suction effect caused by the increased surface area of ​​the side surface of the cavity also helps to improve the distribution of the molten metal in the cavity, while for the standard evaporation boat, fluid displacement is the main mechanism for spreading the molten metal on the cavity. As an effect, when the same metal wire feed rate and the same total evaporation rate are used, the molten metal pool of the evaporation boat disclosed herein is thinner than that of the standard evaporation boat with a standard cavity. Due to the thinner molten metal pool, the evaporation boat as disclosed herein has a smaller tendency to overheat and pinhole formation. Another advantage is that the thinner molten metal pool improves energy efficiency and reduces the power consumption of the evaporation boat because the parallel resistance of the molten metal pool is increased.

[0081] Since the circumferential length of the outer contour of the cavity is longer than the circumferential length of the shortest circumscribed contour of the cavity, the evaporation boat as disclosed herein has an additional surface area available for evaporation at the upper side of the evaporation boat. The additional surface area available for evaporation at the upper side of the evaporation boat is equal to the difference between the circumferential length of the outer contour of the cavity and the circumferential length of the shortest circumscribed contour of the cavity multiplied by the depth of the cavity.

[0082] The evaporation boat as disclosed herein may have a cross-sectional area with a rectangular shape. The rectangular cross-sectional area is perpendicular to the longitudinal axis of the evaporation boat. Other cross-sectional areas are also possible.

[0083] The two clamping surfaces of the evaporation boat disclosed herein are generally parallel to each other, and the longitudinal axis is perpendicular to the two clamping surfaces of the evaporation boat. The rectangular cross-sectional area is generally parallel to the clamping surfaces.

[0084] In some embodiments, at least one portion of the evaporation boat has a cross-sectional area with a trapezoidal shape. The trapezoidal cross-sectional area is perpendicular to the longitudinal axis of the evaporation boat, which means that it is generally parallel to the clamping surface. For these embodiments, the upper side of the evaporation boat is parallel to the lower side of the evaporation boat, and each of the two side surfaces of the evaporation boat can be inclined at an angle of 30 degrees to less than 90 degrees relative to the upper side of the evaporation boat in at least one portion of the evaporation boat having a cross-sectional area with a trapezoidal shape.

[0085] In some embodiments, at least one portion of the evaporation boat has a cross-sectional area with a triangular shape. The triangular cross-sectional area is perpendicular to the longitudinal axis of the evaporation boat, i.e., generally parallel to the clamping surface. In this case, the lower side of the evaporation boat corresponds to the two side surfaces of the evaporation boat that are inclined relative to the upper side of the evaporation boat.

[0086] In some embodiments, at least one portion of the evaporation boat has a cross-sectional area with a semi-elliptical form. In this case, the lower side of the evaporation boat has a semi-elliptical form. The two side surfaces of the evaporation boat correspond to the right and left parts of the bisecting ellipse of the lower side of the evaporation boat.

[0087] The evaporation boat as disclosed herein may have a length of 90 mm to 170 mm, a width of 15 mm to 50 mm at the upper side, and a height of 6 mm to 12 mm.

[0088] The evaporation boat as disclosed herein is heated by direct current.

[0089] Also disclosed herein is a method for evaporating metal using an evaporation boat as disclosed herein, the method comprising:

[0090] The metal in solid form is continuously supplied to the upper side of the evaporation boat,

[0091] The evaporation boat as disclosed herein is heated by direct current.

[0092] Melting the metal in the chamber of the evaporation boat, and

[0093] The metal is evaporated from the upper side of the evaporation boat.

[0094] Various embodiments of evaporation boats according to the present disclosure are shown in the accompanying drawings.

[0095] Figure 1A A plan view of the upper side 2 of a reference evaporation boat 1 is shown. Figure 1B Shows Figure 1A 3D view of the evaporation boat 1. Figure 1C Shows Figure 1A to Figure 1B The evaporation boat 1 Figure 1A and Figure 1B1C. The metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. Figure 1B In FIG. 1 , one of the two side surfaces 14 and one of the two clamping surfaces 15 of the reference evaporation boat 1 are also shown.

[0096] Figure 1A The upper side 2 of the evaporation boat 1 includes a cavity 4. The cavity 4 is a recessed portion located in the upper side of the evaporation boat. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated. The cavity 4 has an outer contour 5 at the upper side 2 of the evaporation boat 1. The cavity 4 has a bottom surface 11 and a side surface 12 along the outer contour 5 of the cavity 4. The side surface 12 of the cavity 4 extends from the outer contour 5 of the cavity 4 to the bottom surface 11 of the cavity 4 at the upper side 2 of the evaporation boat 1. The bottom surface 11 is parallel to the lower side 3 of the evaporation boat 1. The angle enclosed by the surface area of ​​the upper side 2 of the evaporation boat 1 outside the outer contour 5 of the cavity 4 and the side surface 12 of the cavity 4 is 90°. The outer contour 5 of the cavity 4 corresponds to the shortest circumscribed contour 6 of the outer contour 5 of the cavity 4. The shortest circumscribed contour 6 is the shortest contour of the circumscribed outer contour 5. The circumferential length of the shortest circumscribed contour 6 corresponds to the circumferential length of the outer contour 5 , and the ratio of the circumferential length of the shortest circumscribed contour 6 to the circumferential length of the outer contour 5 is 1.0.

[0097] Figure 1D Schematically shows the Figure 1B 1. The upper side 2 of the evaporation boat 1 is wetted by molten aluminum. The area 13 wetted by the molten aluminum is schematically shown as a shaded area.

[0098] Figure 2A A plan view of an upper side 2 of an evaporation boat 1 as disclosed herein is shown. Figure 2B Shows Figure 2A 3D view of the evaporation boat 1. Figure 2C Shows FIG. 2A to FIG. 2B The evaporation boat 1 Figure 2A and Figure 2B A cross-sectional view taken at the section line indicated by “2C” in FIG. Figure 2D Shows FIG. 2A to FIG. 2B The evaporation boat Figure 2A and Figure 2B 2D. The metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. Figure 2B In the figure, one of the two side surfaces 14 of the evaporation boat 1 and one of the two clamping surfaces 15 are also shown. The upper side 2 of the evaporation boat comprises a cavity 4. The cavity 4 is a recess in the upper side of the evaporation boat. FIG. 2A to FIG. 2DThe cavity 4 of the evaporation boat 1 comprises a single recess 20. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated. The cavity 4 has an outer contour 5 at the upper side 2 of the evaporation boat 1. The outer contour 5 is formed by a segment of a circular line. The cavity 4 has a bottom surface 11 and a side surface 12 along the outer contour 5 of the cavity 4. The side surface 12 of the cavity 4 extends from the outer contour 5 of the cavity 4 to the bottom surface 11 of the cavity 4 at the upper side 2 of the evaporation boat 1. The bottom surface 11 is parallel to the lower side 3 of the evaporation boat 1. The angle enclosed by the surface area of ​​the upper side 2 of the evaporation boat 1 outside the outer contour 5 of the cavity 4 and the side surface 12 of the cavity 4 is 90°.

[0099] Figure 2E Shows Figure 2B 2. A plan view of the upper side of the evaporation boat. Figure 2A In addition to the floor plan, Figure 2E Also shown in FIG. 4 is the shortest circumscribed contour 6 of the outer contour 5 of the chamber 4. The shortest circumscribed contour 6 is the shortest contour of the circumscribed outer contour 5. The shortest circumscribed contour is of course not a real contour present at the upper side 2 of the evaporation boat 1, but a theoretical contour for explanation purposes. Figure 2E In FIG. 6 , the shortest circumscribed contour 6 is shown as a dotted line. Figure 2E As can be seen in the figure, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The ratio of the circumferential length of the shortest circumscribed contour 6 to the circumferential length of the outer contour 5 is 0.93. The outer contour 5 of the cavity 4 includes eight inwardly directed extensions 10. Four of these extensions are located along each of the two side surfaces of the evaporation boat. The eight inwardly directed extensions of the outer contour can be regarded as extensions of the shortest circumscribed contour 6 of the outer contour 5. Due to these extensions, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The eight inwardly directed extensions of the outer contour can also be regarded as extensions of the side surfaces of the cavity.

[0100] like Figure 2B and Figure 2E As shown in FIG. 1 , the ratio of the area enclosed by the outer contour 5 of the chamber 4 to the total surface area of ​​the upper side 2 of the evaporation boat 1 is 0.28. The area enclosed by the outer contour 5 of the chamber 4 can also be larger than Figure 2B and Figure 2E The ratio of the area shown in FIG. 1 and the area enclosed by the outer contour 5 of the chamber 4 to the total surface area of ​​the upper side 2 of the evaporation boat 1 can also be as high as 0.7 or as high as 0.95. For example, the width of the area outside the shortest circumscribed contour and along the side surface of the evaporation boat can be as small as 1 mm, and the width of the area outside the shortest circumscribed contour and close to the clamping area of ​​the evaporation boat can be only 5 mm. FIG. 2A to FIG. 2E In the evaporation boat shown in FIG, the ratio of the minimum width of the cavity 4 to the maximum width of the cavity 4 is 0.75.

[0101] Figure 2FSchematically shows the Figure 2B 1. The upper side 2 of the evaporation boat 1 is wetted by molten aluminum. The area 13 wetted by the molten aluminum is schematically shown as a shaded area.

[0102] For Figure 1D The reference evaporation boat with a standard cavity shown in FIG, the side surface of the cavity is the boundary of the molten metal. At the two longer sides of the cavity, the molten metal will not overflow from the side surface of the cavity to the upper side of the evaporation boat. For higher evaporation rates, there is a risk that the molten metal will overflow the side surface of the cavity at the two smaller sides of the cavity near the clamping area.

[0103] For FIG. 2A to FIG. 2F In the evaporation boat disclosed herein, the surface area of ​​the side surface of the cavity is greater than Figures 1A to 1D The side surface of the chamber of the reference evaporation boat. Figures 1A to 1D The increase in the surface area of ​​the side surface of the chamber compared to the reference evaporation boat is due to the eight extensions 10 of the outer contour 5 of the chamber 4, i.e. due to Figures 1A to 1D Compared with the reference evaporation boat, the circumferential length of the outer contour of the cavity is increased. FIG. 2A to FIG. 2F The increased side surface area of ​​the cavity of the evaporation boat is an additional surface area where the molten metal can be evaporated. Therefore, the evaporation rate per unit area (e.g., evaporation rate per square millimeter) is locally increased at the outer contour 5 of the cavity 4 due to the increase in the side surface of the cavity. The locally increased evaporation rate helps to guide or draw the molten metal from the wire feed point (i.e., the point where the aluminum wire hits the cavity) to the side surface of the cavity, and exceeds the outer contour of the cavity to reach the upper side of the evaporation boat outside the outer contour of the cavity. Due to the increase in the surface area of ​​the side surface of the cavity, the side surface of the cavity is not the boundary of the molten metal, but the molten metal can overflow the outer contour of the cavity, and can also wet the upper surface of the evaporation boat outside the outer contour of the cavity. This can also be described as a "suction effect" that makes the area wetted by the molten metal wider. For example, FIG. 2A to FIG. 2F The evaporation boat disclosed herein, as shown in FIG. Figures 1A to 1D The reference evaporation boat is wider, i.e. the wetted surface area is wider in the direction perpendicular to the longitudinal axis. This can be seen in Figure 1D Compared to Figure 2F The suction effect caused by the increased surface area of ​​the side surfaces of the cavity also helps to improve the distribution of the molten metal within the cavity, while for the reference evaporation boat, fluid displacement is the main mechanism for spreading the molten metal over the cavity. As an effect, when using the same metal wire feed rate and the same total evaporation rate, the Figure 1D Compared to the reference evaporation boat, Figure 2FThe molten metal pool of the evaporation boat is thinner. Due to the thinner molten metal pool, the evaporation boat as disclosed herein has less tendency to overheat and pinhole formation. The thinner molten metal pool improves energy efficiency and reduces the power consumption of the evaporation boat because the parallel resistance of the molten metal pool is increased.

[0104] Figure 3A Shown is a plan view of an upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. Figure 3B Shows Figure 3A 3D view of the evaporation boat 1. Figure 3C Shows FIG. 3A to FIG. 3B The evaporation boat 1 Figure 3A and Figure 3B A cross-sectional view taken along the section line indicated by “3C” in FIG. Figure 3D Shows FIG. 3A to FIG. 3B The evaporation boat Figure 3A and Figure 3B The metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. Figure 3B In the figure, one of the two side surfaces 14 of the evaporation boat 1 and one of the two clamping surfaces 15 are also shown. The upper side 2 of the evaporation boat comprises a cavity 4. The cavity 4 is a recess in the upper side of the evaporation boat. FIG. 3A to FIG. 3D The cavity 4 of the evaporation boat 1 comprises a single recess 20. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated. The cavity 4 has an outer contour 5 at the upper side 2 of the evaporation boat 1. The outer contour 5 is formed by segments of a circular line connected by straight lines parallel to the side surfaces 14 of the evaporation boat. The cavity 4 has a bottom surface 11 and a side surface 12 along the outer contour 5 of the cavity 4. The side surface 12 of the cavity 4 extends from the outer contour 5 of the cavity 4 to the bottom surface 11 of the cavity 4 at the upper side 2 of the evaporation boat 1. The bottom surface 11 is parallel to the lower side 3 of the evaporation boat 1. The angle enclosed by the surface area of ​​the upper side 2 of the evaporation boat 1 outside the outer contour 5 of the cavity 4 and the side surface 12 of the cavity 4 is 90°.

[0105] Figure 3E Shows Figure 3B 2. A plan view of the upper side of the evaporation boat. Figure 3A In addition to the floor plan, Figure 3E Also shown in FIG. 4 is the shortest circumscribed contour 6 of the outer contour 5 of the chamber 4. The shortest circumscribed contour 6 is the shortest contour of the circumscribed outer contour 5. The shortest circumscribed contour is of course not a real contour present at the upper side 2 of the evaporation boat 1, but a theoretical contour for explanation purposes. Figure 3E In FIG. 6 , the shortest circumscribed contour 6 is shown as a dotted line. Figure 3EAs can be seen in the figure, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The ratio of the circumferential length of the shortest circumscribed contour 6 to the circumferential length of the outer contour 5 is 0.96. The outer contour 5 of the cavity 4 includes six extensions 10 pointing inwardly. Three of these extensions are located along each of the two side surfaces of the evaporation boat. The six inwardly pointing extensions of the outer contour can be regarded as extensions of the shortest circumscribed contour 6 of the outer contour 5. Due to these extensions, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The six inwardly pointing extensions of the outer contour can also be regarded as extensions of the side surfaces of the cavity.

[0106] like Figure 3B and Figure 3E As shown in FIG. 1 , the ratio of the area enclosed by the outer contour 5 of the chamber 4 to the total surface area of ​​the upper side 2 of the evaporation boat 1 is 0.29. The area enclosed by the outer contour 5 of the chamber 4 can also be larger than Figure 3B and Figure 3E The ratio of the area enclosed by the outer contour 5 of the chamber 4 to the total surface area of ​​the upper side 2 of the evaporation boat 1 can also be as high as 0.7 or as high as 0.95. FIG. 3A to FIG. 3E In the evaporation boat shown in FIG. 1 , the ratio of the minimum width of the cavity 4 to the maximum width of the cavity 4 is 0.65.

[0107] Figure 3F Schematically shows the Figure 3B 1 is a plan view of the upper side 2 of the evaporation boat 1. The upper side 2 of the evaporation boat has been wetted by molten aluminum. The area 13 wetted by the molten aluminum is schematically shown as a shaded area. Figure 3F The evaporation boat disclosed herein, as shown in FIG. Figure 1D The reference boat is wider. This can be explained by the additional surface area on the upper side of the evaporation boat, which is available for evaporation and by the increased surface area of ​​the side surfaces of the cavity, which is larger than Figure 1D The side surface of the chamber of the reference evaporation boat. Figure 1D The increase in the surface area of ​​the side surfaces of the cavity compared to the reference boat is due to the six extensions of the outer contour of the cavity. FIG. 2A to FIG. 2F The evaporation boat explains further effects caused by the increased surface area of ​​the side surfaces of the cavity.

[0108] Figure 4A Shown is a plan view of an upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. Figure 4B Shows Figure 4A 3D view of the evaporation boat 1. Figure 4C Shows FIG. 4A to FIG. 4B The evaporation boat 1 Figure 4A and Figure 4BA cross-sectional view taken along the section line indicated by “4C” in FIG. Figure 4D Shows FIG. 4A to FIG. 4B The evaporation boat Figure 4A and Figure 4B 4D. The metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. Figure 4B In the figure, one of the two side surfaces 14 of the evaporation boat 1 and one of the two clamping surfaces 15 are also shown. The upper side 2 of the evaporation boat comprises a cavity 4. The cavity 4 is a recess in the upper side of the evaporation boat. 4A to 4D The cavity 4 of the evaporation boat 1 comprises a single recess 20. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated. The cavity 4 has an outer contour 5 at the upper side 2 of the evaporation boat 1. The outer contour 5 is formed by segments of a circular line connected by straight lines parallel to the side surfaces 14 of the evaporation boat. The cavity 4 has a bottom surface 11 and a side surface 12 along the outer contour 5 of the cavity 4. The side surface 12 of the cavity 4 extends from the outer contour 5 of the cavity 4 to the bottom surface 11 of the cavity 4 at the upper side 2 of the evaporation boat 1. The bottom surface 11 is parallel to the lower side 3 of the evaporation boat 1. The angle enclosed by the surface area of ​​the upper side 2 of the evaporation boat 1 outside the outer contour 5 of the cavity 4 and the side surface 12 of the cavity 4 is 90°.

[0109] Figure 4E Shows Figure 4B 2. A plan view of the upper side of the evaporation boat. Figure 4A In addition to the floor plan, Figure 4E Also shown in FIG. 4 is the shortest circumscribed contour 6 of the outer contour 5 of the chamber 4. The shortest circumscribed contour 6 is the shortest contour of the circumscribed outer contour 5. The shortest circumscribed contour is of course not a real contour present at the upper side 2 of the evaporation boat 1, but a theoretical contour for explanation purposes. Figure 4E In FIG. 6 , the shortest circumscribed contour 6 is shown as a dotted line. Figure 4E As can be seen in the figure, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The ratio of the circumferential length of the shortest circumscribed contour 6 to the circumferential length of the outer contour 5 is 0.74. The outer contour 5 of the cavity 4 includes fourteen extensions 10 pointing inwardly. Seven of these extensions are located along each of the two side surfaces of the evaporation boat. The fourteen inwardly pointing extensions of the outer contour can be regarded as extensions of the shortest circumscribed contour 6 of the outer contour 5. Due to these extensions, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The fourteen inwardly pointing extensions of the outer contour can also be regarded as extensions of the side surfaces of the cavity.

[0110] like Figure 4B and Figure 4EAs shown in FIG. 1 , the ratio of the area enclosed by the outer contour 5 of the chamber 4 to the total surface area of ​​the upper side 2 of the evaporation boat 1 is 0.29. The area enclosed by the outer contour 5 of the chamber 4 can also be larger than Figure 4B and Figure 4E The ratio of the area enclosed by the outer contour 5 of the chamber 4 to the total surface area of ​​the upper side 2 of the evaporation boat 1 can also be as high as 0.7 or as high as 0.95. FIG. 4A to FIG. 4E In the evaporation boat shown in FIG. 1 , the ratio of the minimum width of the cavity 4 to the maximum width of the cavity 4 is 0.60.

[0111] Figure 4F Schematically shows the Figure 4B 1 is a plan view of the upper side 2 of the evaporation boat 1. The upper side 2 of the evaporation boat has been wetted by molten aluminum. The area 13 wetted by the molten aluminum is schematically shown as a shaded area. Figure 4F The evaporation boat disclosed herein, as shown in FIG. Figure 1D The reference boat is wider. This can be explained by the additional surface area on the upper side of the evaporation boat, which is available for evaporation and by the increased surface area of ​​the side surfaces of the cavity, which is larger than Figure 1D The side surface of the chamber of the reference evaporation boat. Figure 1D The surface area of ​​the side surface of the cavity is increased compared to the reference boat due to the fourteen extensions of the outer contour of the cavity. FIG. 2A to FIG. 2F The evaporation boat explains further effects caused by the increased surface area of ​​the side surfaces of the cavity.

[0112] Figure 4G Shown is a plan view of an upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. Figure 4H Shows Figure 4G 3D view of the evaporation boat 1. Fig. 4I Shows Figures 4G to 4H The evaporation boat 1 Figure 4G and Figure 4H A cross-sectional view taken along the section line indicated by “4I” in FIG. Figure 4J Shows Figures 4G to 4H The evaporation boat Figure 4G and Figure 4H A cross-sectional view taken along the section line indicated by "4J" in FIG. Figure 4G As shown in Figure 4G to Figure 4J The upper side 2 of the evaporation boat corresponds to Figure 4A .from FIG. 4H to FIG. 4J It can be seen that the cross-sectional area of ​​the evaporation boat of this embodiment has a trapezoidal shape. Figure 4E As shown in FIG. 4 , the shortest circumscribed contour 6 of the outer contour 5 of the cavity 4 corresponds to FIG. 4A to FIG. 4E The shortest circumscribed contour of the evaporation boat 6. Under operation, the plan view of the evaporation boat corresponds to FIG. 4A to FIG. 4E The plan view of the evaporation boat is as follows: Figure 4F As shown in .

[0113] Figure 5A Shown is a plan view of an upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. Figure 5B Shows Figure 5A 3D view of the evaporation boat 1. Figure 5C Shows FIG. 5A to FIG. 5B The evaporation boat 1 Figure 5A and Figure 5B A cross-sectional view taken along the section line indicated by “5C” in FIG. Figure 5D Shows FIG. 5A to FIG. 5B The evaporation boat Figure 5A and Figure 5B 5D". The metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. Figure 5B In the figure, one of the two side surfaces 14 of the evaporation boat 1 and one of the two clamping surfaces 15 are also shown. The upper side 2 of the evaporation boat comprises a cavity 4. The cavity 4 is a recess in the upper side of the evaporation boat. FIG. 5A to FIG. 5D The cavity 4 of the evaporation boat 1 includes a single recess 20. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated. The cavity 4 has an outer contour 5 at the upper side 2 of the evaporation boat 1. The outer contour 5 is formed by a wavy line along the side surface 14 of the evaporation boat. The cavity 4 has a bottom surface 11 and a side surface 12 along the outer contour 5 of the cavity 4. The side surface 12 of the cavity 4 extends from the outer contour 5 of the cavity 4 to the bottom surface 11 of the cavity 4 at the upper side 2 of the evaporation boat 1. The bottom surface 11 is parallel to the lower side 3 of the evaporation boat 1. The angle enclosed by the surface area of ​​the upper side 2 of the evaporation boat 1 outside the outer contour 5 of the cavity 4 and the side surface 12 of the cavity 4 is 90°.

[0114] Figure 5E Shows Figure 5B 2. A plan view of the upper side of the evaporation boat. Figure 5A In addition to the floor plan, Figure 5E Also shown in FIG. 4 is the shortest circumscribed contour 6 of the outer contour 5 of the chamber 4. The shortest circumscribed contour 6 is the shortest contour of the circumscribed outer contour 5. The shortest circumscribed contour is of course not a real contour present at the upper side 2 of the evaporation boat 1, but a theoretical contour for explanation purposes. Figure 5E In FIG. 6 , the shortest circumscribed contour 6 is shown as a dotted line. Figure 5EAs can be seen in the figure, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The ratio of the circumferential length of the shortest circumscribed contour 6 to the circumferential length of the outer contour 5 is 0.52. The outer contour 5 of the cavity 4 includes sixteen extensions 10 pointing inwardly. Eight of these extensions are located along each of the two side surfaces of the evaporation boat. The sixteen inwardly pointing extensions of the outer contour can also be regarded as extensions of the shortest circumscribed contour 6 of the outer contour 5. Due to these extensions, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The sixteen inwardly pointing extensions of the outer contour can also be regarded as extensions of the side surfaces of the cavity.

[0115] Fig. 6A Shown is a plan view of an upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. Figure 6B Shows Fig. 6A 3D view of the evaporation boat 1. Figure 6C Shows FIG. 6A to FIG. 6B The evaporation boat 1 Fig. 6A and Figure 6B A cross-sectional view taken along the section line indicated by “6C” in FIG. Fig.6D Shows FIG. 6A to FIG. 6B The evaporation boat Fig. 6A and Figure 6B 6D”. The metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. Figure 6B In the figure, one of the two side surfaces 14 of the evaporation boat 1 and one of the two clamping surfaces 15 are also shown. The upper side 2 of the evaporation boat comprises a cavity 4. The cavity 4 comprises a recess 16 located in the upper side 2 of the evaporation boat and an area 17 surrounded by the recess 16. The area 17 surrounded by the recess 16 is the central area of ​​the cavity 4. The recess 16 is located along the outer contour 5 of the cavity 4. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated. The cavity 4 has an outer contour 5 at the upper side 2 of the evaporation boat 1. The outer contour 5 is formed by a segment of a circular line.

[0116] Figures 6A to 6D The depth of the cavity of the evaporation boat is larger near the outer contour of the cavity and smaller in the central area of ​​the cavity (i.e., at a position farther from the outer contour). At a position 16 close to the outer contour of the cavity, the depth of the cavity may be 0.5 mm to 5 mm, for example 3 mm. FIG. 6A to FIG. 6D In the embodiment shown in FIG. 1 , the depth of the cavity in the central region 17 of the cavity is 0 mm. In the central region 17 of the cavity, the depth of the cavity may also be greater, for example 1 to 2 mm.

[0117] The chamber 4 has a bottom surface 11 and a side surface 12 along the outer contour 5 of the chamber 4. The side surface 12 of the chamber 4 extends from the outer contour 5 of the chamber 4 to the bottom surface 11 of the chamber 4 at the upper side 2 of the evaporation boat 1. The central area 17 of the chamber is also the central area of ​​the bottom surface 11 of the chamber 4, and is in the same plane as the upper side 2 of the evaporation boat in the area outside the outer contour 4. The angle enclosed by the surface area of ​​the upper side 2 of the evaporation boat 1 outside the outer contour 5 of the chamber 4 and the side surface 12 of the chamber 4 is 90°.

[0118] The outer contour 5 of the cavity corresponds to the outer contour of the recess 16. The recess 16 has an inner contour 18. The depth of the cavity 5 at a position outside the inner contour 18 is different from the depth of the cavity 5 at a position inside the inner contour 18. The depth of the cavity at the position of the recess 16 (i.e., outside the inner contour 18) may be 0.5 mm to 5 mm, and is greater than the depth of the cavity at the position of the central area 17 of the cavity (i.e., at a position inside the inner contour 18).

[0119] The area enclosed by the outer contour 5 of the chamber includes an area 17 which is in the same plane as the surface area of ​​the upper side 2 of the evaporation boat outside the outer contour 5 of the chamber 4 , in other words the area 17 can also be called an “island”.

[0120] Fig. 6E Shows Figure 6B 2. A plan view of the upper side of the evaporation boat. Fig. 6A In addition to the floor plan, Fig. 6E Also shown in FIG. 4 is the shortest circumscribed contour 6 of the outer contour 5 of the chamber 4. The shortest circumscribed contour 6 is the shortest contour of the circumscribed outer contour 5. The shortest circumscribed contour is of course not a real contour present at the upper side 2 of the evaporation boat 1, but a theoretical contour for explanation purposes. Fig. 6E In FIG. 6 , the shortest circumscribed contour 6 is shown as a dotted line. Fig. 6E As can be seen in the figure, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The ratio of the circumferential length of the shortest circumscribed contour 6 to the circumferential length of the outer contour 5 is 0.93. The outer contour 5 of the cavity 4 includes eight inwardly directed extensions 10. Four of these extensions are located along each of the two side surfaces of the evaporation boat. The eight inwardly directed extensions of the outer contour can be regarded as extensions of the shortest circumscribed contour 6 of the outer contour 5. Due to these extensions, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The eight inwardly directed extensions of the outer contour can also be regarded as extensions of the side surfaces of the cavity.

[0121] Fig. 7A Shown is a plan view of an upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. Figure 7B Shows Fig. 7A 3D view of the evaporation boat 1. Figure 7C Shows FIG. 7A to FIG. 7BThe evaporation boat 1 Fig. 7A and Figure 7B A cross-sectional view taken along the section line indicated by “7C” in FIG. Fig.7D Shows FIG. 7A to FIG. 7B The evaporation boat Fig. 7A and Figure 7B 7D". Metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. The upper side 2 of the evaporation boat comprises a cavity 4. The cavity 4 is formed by three recesses 7 in the upper side 2 of the evaporation boat. Each of the three recesses 7 has an outer contour 8 at the upper side 2 of the evaporation boat 1. The outer contour 5 of the cavity 4 of the evaporation boat 1 is formed by the outer contours 8 of the three individual recesses 7.

[0122] Fig. 7E Shows Figure 7B 2. A plan view of the upper side of the evaporation boat. Fig. 7A In addition to the floor plan, Fig. 7E Also shown in FIG. 1 is the shortest circumscribed contour 9 of the outer contour 8 of each of the three individual recesses 7. The shortest circumscribed contour 9 is the shortest contour of the circumscribed outer contours 8. The shortest circumscribed contour is of course not a real contour present at the upper side 2 of the evaporation boat 1, but a theoretical contour for explanation purposes. Fig. 7E In FIG. 6 , the shortest circumscribed contour 6 is shown as a dotted line. The shortest circumscribed contour 9 has a circular shape, i.e., the shortest circumscribed contour is a circumscribed circle. Fig. 7E As can be seen in FIG. 1 , for each of the three recesses 7, the circumferential length of the shortest circumscribed contour 9 is shorter than the circumferential length of the outer contour 8. The sum of the circumferential lengths of the outer contours 8 of the individual recesses 7 is the circumferential length of the outer contour 5 of the cavity 4 of the evaporation boat 1. The sum of the circumferential lengths of the shortest circumscribed contours 9 of the individual recesses 7 is the circumferential length of the shortest circumscribed contour 6 of the cavity 4 of the evaporation boat 1.

[0123] The outer contour 8 of the three grooves 7 each includes twelve extensions 10 pointing inwardly to the center of the circumscribed circle. The twelve inwardly directed extensions can be regarded as extensions of the shortest circumscribed contour 9 of the outer contour 8. It is also possible for the recess 7 to have more or fewer extensions than twelve, for example three to twenty extensions. The extensions 10 have a rounded shape that is close to the circumscribed circle and is located at the innermost part of the extension that is closest to the center of the circumscribed circle. Due to these extensions, the circumferential length of the shortest circumscribed contour 9 is shorter than the circumferential length of the outer contour 8.

[0124] Figure 8 and Fig. 9 Each shows a plan view of the upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. These embodiments are similar to Figure 7B An embodiment in which the cavity 4 is composed of three separate recesses 7. Fig. 9The extension 10 has a rounded shape that is close to the circumscribed circle and is located at the innermost portion of the extension that is closest to the center of the circumscribed circle. Figure 8 The extension 10 has a triangular shape.

[0125] Figures 10 to 12 Each shows a plan view of the upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. These embodiments have a cavity 4 consisting of a single recess in the upper side 2 of the evaporation boat 1 . Fig.10 The outer contour 5 of the cavity 4 of the embodiment comprises a meander line, Fig.11 The outer contour 5 of the chamber 4 of the embodiment comprises an inwardly directed extension 10 which has a rounded shape and has extensions of different lengths in a direction parallel to the clamping surface of the evaporation boat (ie in a direction perpendicular to the longitudinal axis of the evaporation boat), and Fig.12 The outer contour 5 of the cavity 4 of the embodiment includes an extension 10 extending from the shortest circumscribed contour 6 also at the two smaller sides of the cavity 4 near the clamping area. The minimum width of the cavity in a direction perpendicular to the longitudinal axis of the evaporation boat and the maximum width of the cavity in a direction perpendicular to the longitudinal axis of the evaporation boat are measured at the position of the extension 19 near the outside of the clamping area.

[0126] Fig.13A Shown is a plan view of an upper side 2 of another embodiment of an evaporation boat 1 as disclosed herein. Fig. 13B Shows Fig.13A 3D view of the evaporation boat 1. Fig. 13C Shows FIG. 13A to FIG. 13B The evaporation boat 1 is Fig.13A 13C. The metal is evaporated from the upper side 2 of the evaporation boat 1. The upper side 2 has a rectangular shape. The lower side 3 of the evaporation boat 1 also has a rectangular shape. Fig. 13B In the figure, one of the two side surfaces 14 of the evaporation boat 1 and one of the two clamping surfaces 15 are also shown. The upper side 2 of the evaporation boat comprises a cavity 4. The cavity 4 is a recess in the upper side of the evaporation boat. FIG. 13A to FIG. 13C The cavity 4 of the evaporation boat 1 comprises a single recess 20. Under operation of the evaporation boat, the cavity is wetted by the liquid metal to be evaporated. The cavity 4 has an outer contour 5 at the upper side 2 of the evaporation boat 1. The outer contour 5 is formed by segments of a circular line connected by straight lines. Along the two side surfaces 14 of the evaporation boat, the outer contour 5 has the form of a meandering line with rounded corners. In addition, the cavity 4 has a meandering form with rounded corners.

[0127] The cavity 4 has a bottom surface 11 and a side surface 12 along the outer contour 5 of the cavity 4. The side surface 12 of the cavity 4 extends from the outer contour 5 of the cavity 4 to the bottom surface 11 of the cavity 4 at the upper side 2 of the evaporation boat 1. The bottom surface 11 is parallel to the lower side 3 of the evaporation boat 1. The angle enclosed by the surface area of ​​the upper side 2 of the evaporation boat 1 outside the outer contour 5 of the cavity 4 and the side surface 12 of the cavity 4 is 90°.

[0128] Fig.13D Shows Fig. 13B 2. A plan view of the upper side of the evaporation boat. Fig.13A In addition to the floor plan, Fig.13D Also shown in FIG. 4 is the shortest circumscribed contour 6 of the outer contour 5 of the chamber 4. The shortest circumscribed contour 6 is the shortest contour of the circumscribed outer contour 5. The shortest circumscribed contour is of course not a real contour present at the upper side 2 of the evaporation boat 1, but a theoretical contour for explanation purposes. Fig.13D In FIG. 6 , the shortest circumscribed contour 6 is shown as a dotted line. Fig.13D As can be seen in the figure, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The ratio of the circumferential length of the shortest circumscribed contour 6 to the circumferential length of the outer contour 5 is 0.57. The outer contour 5 of the cavity 4 includes eight inwardly directed extensions 10. The eight extensions are extensions extending inwardly from the shortest circumscribed contour 6 of the outer contour 5. Four of these extensions are located along each of the two side surfaces of the evaporation boat. The eight inwardly directed extensions of the outer contour can also be regarded as extensions of the shortest circumscribed contour 6 of the outer contour 5. Due to these extensions, the circumferential length of the shortest circumscribed contour 6 is shorter than the circumferential length of the outer contour 5. The eight inwardly directed extensions of the outer contour can also be regarded as extensions of the side surfaces of the cavity.

[0129] The width of the extension in the direction parallel to the longitudinal axis of the evaporation boat is 3 mm. The lengths of the extension in the direction perpendicular to the longitudinal axis of the evaporation boat are 12 mm, 17 mm and 22 mm, respectively. The width of the evaporation boat is 38 mm, and the maximum width of the cavity in the direction perpendicular to the longitudinal axis of the evaporation boat is 34 mm. The minimum width of the cavity in the direction perpendicular to the longitudinal axis is 12 mm, and the minimum width of the cavity in the direction parallel to the longitudinal axis is 8 mm.

[0130] The materials used to make the evaporation boat disclosed herein may include titanium diboride and boron nitride. In some embodiments, the materials used to make the evaporation boat also include titanium diboride, boron nitride, and aluminum nitride. The titanium diboride content in the materials used to make the evaporation boat is generally in the range of 25% to 40% by volume.

[0131] The volume of the evaporation boat disclosed herein is generally about 25 cm 3 Up to 85cm 3 within the range.

[0132] The evaporation boat disclosed herein can be made by conventional methods, such as hot pressing a powder mixture containing titanium diboride and boron nitride into a hot pressed body and machining the evaporation boat from the hot pressed body. An evaporation boat having a rectangular, trapezoidal or other cross-sectional area can be produced by machining such as sawing. The upper side of the evaporation boat from which the metal is evaporated can be produced by machining such as grinding and milling. The cavity of the evaporation boat can be produced by machining such as grinding and milling.

[0133] According to common practice for ceramic materials, the edges of an evaporation boat as disclosed herein may be chamfered, ie, rounded.

[0134] The evaporation boat as disclosed herein can be used to evaporate a metal selected from the group consisting of aluminum, copper and silver. In some embodiments of the present disclosure, the evaporation boat is used to evaporate a transparent aluminum oxide (AlO x ) coated aluminum.

[0135] Example

[0136] Examples 1 to 3 (EX1 to EX3) and Comparative Example (CEX)

[0137] like FIG. 2A to FIG. 2E (Example 1), 3A to Figure 3E (Example 2) and 4A to Figure 4E An evaporation boat according to the present disclosure shown in (Example 3) was prepared and tested in a laboratory coater under conditions typical of a standard web coating process.

[0138] For comparison, we also tested Figures 1A to 1C The dimensions of all tested evaporation boats were 9 mm×38 mm×130 mm. All evaporation boats were made from one batch of a powder mixture comprising titanium diboride and boron nitride, wherein the titanium diboride content was 47.0 wt %.

[0139] The aluminum feed rate, which is the amount of aluminum fed to the boat in one minute, was increased stepwise to a maximum rate of 11 g / min.

[0140] The results obtained for power consumption are shown in Table 1. The power consumption of the comparative example is set to 100% as a reference. The power consumption of Examples 1 to 3 is expressed as a percentage of the power consumption of the comparative example. The value of power consumption for a specific aluminum feed rate in Table 1 is the average value of three evaporation boats over the entire time when running this specific aluminum feed rate (e.g., 4.1 g / min, as indicated in Table 1).

[0141] Table 1 :

[0142]

[0143] As can be seen from Table 1, at higher aluminum feed rates, the total power consumption of Examples 1, 2, and 3 is lower than that of the reference evaporation boat (comparative example). This indicates that the thickness of the liquid aluminum in the cavity of the evaporation boats of Examples 1, 2, and 3 is lower than that of the reference evaporation boat. By this effect, the so-called pinholes in the metallized film can be minimized.

[0144] In addition, the upper side of the tested evaporation boat with the liquid metal pool is schematically drawn. Figure 1D , Figure 2F , Figure 3F and Figure 4F , the area 13 wetted by the molten aluminum is schematically shown as a shaded area. From these figures, it can be seen that for Examples 1, 2 and 3, there is a much wider wetted area in the boat width than the reference evaporation boat of the comparative example, and for the reference evaporation boat of the comparative example, the tendency of aluminum to flow toward the copper fixture is much higher than that of Examples 1, 2 and 3.

Claims

1. An evaporation boat (1) for evaporating metal, wherein the evaporation boat (1) has an upper side (2), a lower side (3), two side surfaces (14) and two clamping surfaces (15), and wherein metal is evaporated from the upper side (2) of the evaporation boat, and wherein the upper side (2) of the evaporation boat comprises a cavity (4), and wherein the cavity (4) has an outer contour (5) at the upper side (2) of the evaporation boat, and wherein the outer contour (5) of the cavity (4) has a shortest circumscribed contour (6), and wherein the outer contour (5) has a circumferential length, and wherein the shortest circumscribed contour (6) has a circumferential length, and wherein the ratio of the circumferential length of the shortest circumscribed contour (6) to the circumferential length of the outer contour (5) is at least 0.1 and at most 0.8, and wherein the shortest circumscribed contour (6) is a circle, a polygon or a combination of a polygon and one or more curves or circular parts, and wherein the chamber (4) is constituted by a single recess (20) located in the upper side (2) of the evaporation boat (1), and wherein the area enclosed by the outer contour (5) of the chamber (4) is a continuous area, and wherein the area enclosed by the outer contour (5) of the chamber does not include an area in the same plane as the surface area of ​​the upper side of the evaporation boat outside the outer contour of the chamber, and wherein the evaporation boat (1) has a longitudinal axis, and wherein the chamber (4) has a minimum width in a direction perpendicular to the longitudinal axis, and wherein the minimum width of the chamber in a direction perpendicular to the longitudinal axis is at least 5 mm, and wherein the outer contour (5) of the cavity (4) comprises at least four extensions directed inwardly, and wherein the at least four extensions are extensions extending inwardly from the shortest circumscribed contour of the outer contour, and wherein the length of the extensions in a direction perpendicular to the longitudinal axis of the evaporation boat is at least 1 mm and at most the maximum width of the cavity minus 3 mm; And wherein each extension (10) of the outer contour (5) of the cavity (4) has three different lengths, and wherein the average length of the extension in a direction perpendicular to the longitudinal axis of the evaporation boat is 10% to 90% of the maximum width of the cavity, and wherein a first length of the three different lengths of the extension in a direction perpendicular to the longitudinal axis of the evaporation boat corresponds to 10% to 90% of the maximum width of the cavity, and wherein a second length of the three different lengths of the extension in a direction perpendicular to the longitudinal axis of the evaporation boat corresponds to the first length of the three lengths minus 0.1 mm to 10 mm, and wherein a third length of the three different lengths of the extension in a direction perpendicular to the longitudinal axis of the evaporation boat corresponds to the first length of the three lengths plus 0.1 mm to 10 mm.

2. The evaporation boat according to claim 1, wherein the minimum width of the cavity in the direction perpendicular to the longitudinal axis is determined by measuring the minimum width of the cavity in the direction perpendicular to the longitudinal axis at the end of the extension portion, and wherein in order to determine the minimum width of the cavity in the direction perpendicular to the longitudinal axis, the minimum width of the cavity is not measured at both ends of the cavity in the longitudinal direction.

3. The evaporation boat according to claim 1, wherein the ratio of the circumferential length of the shortest circumscribed contour (6) to the circumferential length of the outer contour (5) is at most 0.

75.

4. The evaporation boat according to claim 1, wherein the ratio of the circumferential length of the shortest circumscribed contour (6) to the circumferential length of the outer contour (5) is at least 0.

35.

5. The evaporation boat according to claim 1, wherein the ratio of the area enclosed by the outer contour (5, 8) of the chamber (4) to the total surface area of ​​the upper side (2) of the evaporation boat (1) is at least 0.15 and at most 0.

95.

6. The evaporation boat according to claim 1, wherein the chamber (4) has a zigzag form.

7. The evaporation boat according to claim 1, wherein the respective extensions (10) of the outer contour (5) of the chamber (4) are arranged in an alternating manner along two side surfaces (14) of the evaporation boat (1).

8. The evaporation boat (1) according to claim 1, wherein the cavity (4) has a bottom surface (11), and wherein the cavity (4) has a side surface (12) along the outer contour (5) of the cavity (4), and wherein the side surface (12) of the cavity (4) extends from the outer contour (5) of the cavity (4) at the upper side (2) of the evaporation boat (1) to the bottom surface (11) of the cavity (4), and wherein an angle enclosed by a surface area of ​​the upper side (2) of the evaporation boat (1) outside the outer contour (5) of the cavity (4) and the side surface (12) of the cavity (4) is 45° to 135°.

9. The evaporation boat (1) according to claim 1, wherein the ratio of the depth of the cavity (4) to the height of the evaporation boat (1) is 0.03 to 0.65, and wherein the depth of the cavity is measured at a position having a maximum depth.

10. The evaporation boat (1) according to any one of claims 1 to 9, wherein the material made of the evaporation boat (1) comprises titanium diboride and boron nitride.

11. Use of an evaporation boat (1) according to any one of claims 1 to 9 for evaporating a metal selected from the group consisting of aluminum, copper and silver.

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