Optimized crucible assembly and method for physical vapor deposition

Abstract

The invention relates to a crucible assembly for physical vapor deposition on a surface, the crucible assembly comprising: - a susceptor (22) for supporting and driving a crucible (18) in rotation about an axis of rotation (A), the susceptor comprising a susceptor upper surface (34) having a first alignment relief (30), - a crucible (18) comprising: - at least one cavity (24) arranged at a peripheral region (38) of the crucible (18) with respect to the axis of rotation (A), - a crucible bottom surface (25) intended to contact the susceptor upper surface (34) of the susceptor (22), the crucible bottom surface (25) having a second alignment relief (32) complementary in shape with respect to the first alignment relief (30), the second alignment relief (32) being arranged at a central region (36) of the crucible (18) with respect to the axis of rotation (A).

Description

[0001] This invention relates to a crucible assembly for physical vapor deposition of a material layer onto a surface, such as an ophthalmic lens. The invention also relates to a method for physical vapor deposition using such a crucible assembly.

[0002] Layer deposition is a method used in many industries to form coatings to protect surfaces and / or impart various desired properties to said surfaces. For example, in optics, anti-reflective (AR) layers are a type of optical layer applied to the surface of lenses or other optical devices to reduce reflections.

[0003] Physical vapor deposition is a known method performed in a vacuum, in which a target composed of a material is bombarded with an energy beam. The energy beam causes atoms from the target to transform into a gaseous phase. These atoms then precipitate into a solid form, simultaneously coating multiple substrates with layers of the material in a vacuum chamber.

[0004] The material to be evaporated is typically placed in a material container within the cavity of a crucible. The crucible is configured to cool the material container along with the material to dissipate the large amount of heat generated by the energy beam bombardment. In use, the material is evaporated by the energy beam bombardment and then deposited onto a surface. When there is insufficient material in the container, it is manually removed from the crucible, cleaned, and refilled with new material by the operator. This replacement operation is costly, especially because the layer deposition machine must be stopped during this operation. Furthermore, the replacement operation can be risky due to the high temperatures of the crucible and container.

[0005] One problem that this invention aims to solve is to provide a crucible assembly for physical vapor deposition that allows for improved efficiency of the method while making it safer for the operator.

[0006] To address this problem, the present invention provides a crucible assembly for physical vapor deposition on a surface, the crucible assembly comprising:

[0007] - A base for supporting and driving the crucible to rotate about a rotation axis, the base including an upper surface having a first alignment protrusion / recess.

[0008] - A crucible, comprising:

[0009] • At least one cavity for receiving material to be evaporated onto a surface by an electron beam gun, the at least one cavity being disposed in the peripheral region of the crucible relative to the axis of rotation.

[0010] • The crucible bottom surface is intended to contact the upper surface of the base. The crucible bottom surface has a second alignment protrusion that is complementary to the first alignment protrusion, so that when the crucible bottom surface contacts the upper surface of the base and the first and second alignment protrusions come together, the base and the crucible are aligned with respect to the axis of rotation. The second alignment protrusion is located in the central region of the crucible with respect to the axis of rotation.

[0011] The crucible and base are provided with alignment protrusions and recesses located in the central region of the crucible near the axis of rotation, which allows for an increase in the number of cavities that can be set into the crucible for crucibles of the same external size.

[0012] It has been observed that the maximum external dimension of the crucible available for setting the cavity (the maximum diameter when the crucible is circular) depends on the positioning of these alignment protrusions and recesses. In practice, cavities formed in the crucible typically have a depth close to the crucible thickness. Since the alignment protrusions and recesses can at least partially form depressions, they may prevent the cavity from being positioned in the same location. For a given outer diameter crucible, the maximum usable diameter for setting the cavity is therefore larger when the alignment protrusions and recesses are positioned in the central region of the crucible compared to when they are positioned in the peripheral region.

[0013] Therefore, the crucible is arranged such that the outer region is not aligned with the protrusions and concave parts, thus allowing cavities to be formed at a greater distance from the axis of rotation. Therefore, in a crucible where the protrusions and concave parts are located in the central region, more cavities of a given diameter can be formed.

[0014] A crucible with a larger number of cavities allows for the loading of more material within it. This reduces the number of changeover operations that must be performed during machine operation, thus allowing for increased efficiency of the method. Furthermore, fewer changeover operations reduce the risk to the operator.

[0015] Known crucibles typically comprise six to eight cavities, while crucibles with ten cavities have been achieved where the alignment protrusions are located in the central region of the crucible. This is particularly important for novel antireflective coating processes that require ten or more consecutive material layers. A larger number of cavities allows for the prevention of repeated use of the same material, thereby improving the colorimetric stability of the coating, especially when the material is silica.

[0016] According to an embodiment of the crucible assembly, the crucible includes at least ten cavities disposed in a peripheral region surrounding the axis of rotation.

[0017] According to an embodiment of the crucible assembly, the crucible includes an upper surface extending therefrom the at least one cavity, the upper surface being a circular surface centered on the axis of rotation and defining an outer diameter, wherein:

[0018] - The central region is a circular area extending up to 60% of the outer diameter around the axis of rotation, and / or

[0019] - The outer region is a ring-shaped area extending 61% to 100% of the outer diameter around the axis of rotation.

[0020] According to an embodiment of the crucible assembly, the first alignment protrusion and the second alignment protrusion are one of the following: a depression formed in the surface or a protrusion protruding from the surface.

[0021] According to an embodiment of the crucible assembly, the upper surface of the base further includes a first directional protrusion, and the bottom surface of the crucible further includes a second directional protrusion, the second directional protrusion being complementary in shape to the first directional protrusion, so that when the bottom surface of the crucible contacts the upper surface of the base and the first directional protrusion and the second directional protrusion come together, the crucible is positioned relative to the base at a predetermined angular orientation.

[0022] According to an embodiment of the crucible assembly, the second directional protrusion is positioned at the central region of the crucible.

[0023] According to an embodiment of the crucible assembly, the dimension of the first orientation protrusion along the rotation axis is smaller than the dimension of the first alignment protrusion along the rotation axis.

[0024] According to an embodiment of the crucible assembly, the first alignment protrusion and the second alignment protrusion provide alignment stops for the crucible along at least one direction perpendicular to the axis of rotation.

[0025] According to an embodiment of the crucible assembly, the crucible includes at least one cavity extending therefrom on a crucible upper surface, and the crucible includes a crucible handle extending from the crucible upper surface.

[0026] According to an embodiment of the crucible assembly, the crucible includes at least two cavities, and the crucible assembly further includes a crucible cover configured to cover at least one of the cavities when the crucible cover is positioned above the crucible, the crucible cover having an aperture configured to allow a crucible handle to extend through the crucible cover when the crucible cover is positioned above the crucible.

[0027] According to an embodiment of the crucible assembly, the crucible cover includes a cover handle extending from the upper surface of the cover.

[0028] According to an embodiment of the crucible assembly, the base is disc-shaped, with its upper surface disposed on one side of the disc, and the first alignment protrusion includes a protrusion centered relative to the axis of rotation.

[0029] According to an embodiment of the crucible assembly, the crucible is disc-shaped, with a bottom surface and an upper surface disposed on both sides of the disc, and the second alignment protrusion includes a recess centered relative to the axis of rotation.

[0030] The present invention further provides a method for depositing a coating on a surface using a physical vapor deposition (PVD) machine, the PVD machine comprising:

[0031] Vacuum container,

[0032] • At least one surface to be coated, which is disposed within the vacuum container.

[0033] • A crucible assembly disposed within the vacuum container and having a base configured to cool and drive crucible rotation, the crucible assembly comprising a first crucible and a second crucible, each having multiple cavities for receiving at least one material to be evaporated.

[0034] • Electron beam gun, used to evaporate at least one material.

[0035] The method includes the following steps:

[0036] - Provide a first set of materials and a second set of materials to the cavities of the first crucible and the second crucible, respectively.

[0037] - Position the first crucible containing the first set of materials onto the base.

[0038] -Actuate the electron beam gun to evaporate at least one material received in the cavity of the first crucible.

[0039] Remove the first crucible from the base.

[0040] - Position the second crucible containing the second set of materials onto the base.

[0041] According to an embodiment of the deposition method, the crucible assembly is the crucible assembly as described above.

[0042] The present invention will now be described in more detail with reference to figures, which illustrate only one preferred embodiment of the invention.

[0043] Figure 1 A physical vapor deposition machine including a vacuum container and a crucible assembly therein is shown.

[0044] Figure 2 A detailed view of the vacuum vessel and crucible assembly of a physical vapor deposition machine is shown.

[0045] Figure 3 An exploded view of the crucible assembly, including the base and crucible connected together, the support and the crucible lid, is shown.

[0046] Figure 4 and Figure 5 The top and bottom views of the crucible assembly are shown respectively.

[0047] Figure 6 A top view of the lid, crucible, and base is shown.

[0048] Figure 7 A cross-section of the crucible assembly, in which the crucible is connected to the base and the lid is positioned on top, is shown.

[0049] Figure 8 Alternative embodiments of the crucible are shown.

[0050] Figures 9 to 11 Alternative embodiments of crucible handles or lid handles are shown.

[0051] Figures 12 to 14 Perspective, top, and cross-sectional views of alternative embodiments of the crucible assembly are shown, respectively.

[0052] like Figure 1 and Figure 2 As shown, the physical vapor deposition (PVD) machine 10 includes a vacuum container 12 that can be selectively placed under vacuum and a crucible assembly 14 disposed within the vacuum container 12. The PVD machine 10 also includes a rotating disk 16 forming a bell shape, on which a surface 17 to be coated is disposed. Surface 17 can be any surface on which a coating can be deposited. In a preferred embodiment, surface 17 is the surface of an ophthalmic lens. The coating deposited by vapor deposition is preferably an anti-reflective layer. The crucible assembly 14 is preferably disposed at the center of the vacuum container 12, with the rotating disk 16 above the crucible assembly 14. PVD further includes an electron beam gun (not shown) to evaporate the material disposed within the crucible assembly 14.

[0053] like Figure 3 As shown, the crucible assembly 14 includes a crucible 18 configured to receive material to be evaporated, a support 20, and a base 22 for connecting the crucible 18 to the support 20. The crucible 18 and the base 22 are shown in contact with each other in the connected position. In the connected position, the bottom surface 25 of the crucible contacts the upper surface 34 of the base. The bottom surface 25 of the crucible is disposed opposite to the upper surface 26 of the crucible, where the material to be evaporated is received. In this connected position, the crucible 18 is operable to perform physical vapor deposition when the base is secured to the support 20.

[0054] The crucible 18 includes a plurality of cavities 24 therein for receiving material to be evaporated. Preferably, the crucible 18 includes at least ten cavities 24. The material can be received in a removable container disposed in one or more cavities 24 for easy material replacement and cleaning operations. The cavities 24 are formed on the upper surface 26 of the crucible. In other words, the cavities 24 form blind holes opening into the upper surface 26 of the crucible within the crucible 18. More generally, the crucible 18 is disc-shaped, with a bottom surface 25 and an upper surface 26 disposed on opposite sides of the disc, and a circular side surface 28 disposed between the bottom surface 25 and the upper surface 26. The cavities 24 are preferably arranged in a circular configuration on the upper surface 26 of the crucible.

[0055] The bombardment of the material received in cavity 24 significantly increases the temperature of both the material and the crucible 18. A cooling circuit is provided in support 20 to allow cooling of the material received in cavity 24. The cooling circuit cools the material via cooling base 22 and then cools the crucible 18 via heat conduction between the crucible 18 and base 22. The crucible 18 and base 22 are preferably made of a material that facilitates heat conduction (e.g., copper).

[0056] The support 20 also includes a drive mechanism configured to drive the base 22 to rotate about the axis of rotation A. This rotational motion is then transmitted to the crucible 18 via the base 22. Rotating the crucible 18 about the axis of rotation A allows the position of the cavity 24 to be changed, thereby positioning a predetermined cavity 24 in front of the electron beam gun. This rotation can be performed using a rotating platform to which the base 22 is mounted. The base 22 is configured to rotate the crucible 18 about the axis of rotation A when attached to it. In other words, the base 22, fixed to the support 20, forms a rotating turntable to rotate the crucible 18. The circular configuration of the cavity 24 is centered on the axis of rotation A so that the rotation of the crucible 18 allows the cavity 24 to move about the axis of rotation A. This allows a predetermined cavity 24, and thus a predetermined material, to be positioned in front of the electron beam gun. A controller is also provided to control the drive mechanism and thus control which cavity 24 of the crucible 18 is positioned in front of the electron beam.

[0057] The connection between the base 22 and the crucible 18 is achieved by a first alignment protrusion 30 provided on the base 22 and a second alignment protrusion 32 provided on the crucible 18. The term "protrusion" refers to a recess, protrusion, or combination thereof extending from the surface of the base 22 or the crucible 18. The first alignment protrusion 30 and the second alignment protrusion 32 are configured to fit together to connect the crucible 18 and the base 22. The term "fit together" means that one of the first alignment protrusion 30 and the second alignment protrusion 32 can be inserted into the other. The first alignment protrusion 30 and the second alignment protrusion 32 are preferably complementary in shape to facilitate the connection between the crucible 18 and the base 22.

[0058] According to a preferred embodiment, one of the first alignment protrusion 30 and the second alignment protrusion 32 forms a protrusion configured to fit into a recess formed by the other of the first alignment protrusion 30 and the second alignment protrusion 32. Most preferably, the first alignment protrusion 30 forms a protrusion and the second alignment protrusion 32 forms a recess. This configuration allows for a plug-and-play connection between the crucible 18 and the base 22. Furthermore, it allows for a flat crucible bottom surface 25, i.e., without protrusions, thereby improving the stability of the crucible 18 when placed on another surface.

[0059] The first alignment protrusion 30 and the second alignment protrusion 32 provide alignment stops for the crucible 18 along at least one direction perpendicular to the axis of rotation A. Since the base 22 is fixed to the support 20, the first alignment protrusion 30 and the second alignment protrusion 32, when assembled together, allow the crucible 18 to be positioned relative to the base 22 along at least one direction. Most preferably, the first alignment protrusion 30 and the second alignment protrusion 32 are configured to position the crucible 18 along at least two directions perpendicular to the axis of rotation A.

[0060] The first alignment protrusion 30 and the second alignment protrusion 32 preferably have a circular cross-section, such as Figure 5 and Figure 6 As shown. The circular cross-section allows the crucible 18 to be positioned in two directions when the first and second alignment protrusions are in contact, thereby improving the positioning of the crucible 18 relative to the base 22. The circular cross-section has the advantage of being easy to manufacture. Figure 5 and Figure 6 As shown, the first alignment protrusion 30 may be a cylindrical protrusion projecting from the upper surface 34 of the base. When the crucible 18 and the base 22 are joined together, this upper surface 34 of the base is intended to contact the bottom surface 25 of the crucible. The second alignment protrusion 32 may be a cylindrical recess formed on the bottom surface 25 of the crucible. Alternatively, the first alignment protrusion 30 may be a cylindrical recess and the second alignment protrusion 32 may be a cylindrical protrusion. In another alternative embodiment, the first alignment protrusion 30 and the second alignment protrusion 32 may be any shape that allows the crucible to stop in at least one, preferably both, directions perpendicular to the axis of rotation A. Furthermore, one of the first alignment protrusion 30 and the second alignment protrusion 32 may be a recess, and an insert is configured to be inserted into said recess to form a protrusion.

[0061] The first alignment protrusion 30 and the second alignment protrusion 32 are preferably centered relative to the axis of rotation A so that when the bottom surface 25 of the crucible contacts the upper surface 34 of the base and the first alignment protrusion 30 and the second alignment protrusion 32 come together, both the base 22 and the crucible 18 are aligned relative to the axis of rotation A. The centered first alignment protrusion 30 and the second alignment protrusion 32 facilitate the connection of the crucible 18 to the base 22, as assembling the two components together is generally more intuitive and simpler when the connection interface is centered.

[0062] like Figures 4 to 7 As shown, the crucible 18 forms a central region 36 centered on the axis of rotation A and a peripheral region 38 surrounding the central region 36. A second alignment protrusion 32 is disposed in the central region of the crucible 18, and cavities 24 are disposed in the peripheral region 38. As described above, the crucible 18 is arranged such that the peripheral region 38 does not have an alignment protrusion, thereby allowing cavities 24 to be disposed at a greater distance from the axis of rotation A. Therefore, in the crucible 18 where the second alignment protrusion 32 is disposed in the central region 36, more cavities 24 of a given diameter can be disposed. Specifically, it allows the crucible 18 to have cavities exceeding its height, and preferably at least ten cavities with an outer diameter of 28.97 mm, on the upper surface 26 of the crucible for a crucible outer diameter of 133.00 mm. According to this arrangement, a first alignment protrusion 30 is also disposed in the central region of the base 22, and when the crucible 18 is attached to the base 22, the first alignment protrusion 30 aligns with or faces the second alignment protrusion 32.

[0063] like Figure 4 As shown, all cavities 24 of the crucible 18 can have the same size and shape, thereby providing a uniform distribution of cavities 24 at the same distance from the rotation axis A. Alternatively, the cavities 24 may not have the same shape and / or size, and may be located at different distances from the rotation axis A. Specifically, two cavities 24 may be located on the same radius but at different distances from the rotation axis A, such as... Figure 8 As shown. This allows for more cavities 24 in the crucible 18 to be provided so that more different materials can be evaporated, thus applying more layers to the lens. Smaller cavities 24 (with an outer diameter of 10 to 20 mm) can be used to evaporate non-optical layers, such as magnesium fluoride (MgF2), magnesium oxide (MGO), tin dioxide (SnO2), and indium tin oxide (ITO).

[0064] At least one cavity 24 extends from its upper crucible surface 26, which is preferably a circular surface centered on the axis of rotation A. Thus, the upper crucible surface 26 defines the outer diameter between two portions of the outer edge of the crucible 18. The central region 36 is preferably a circular region extending around the axis of rotation A and having a diameter of up to 50% of the outer diameter of the upper crucible surface 26. The peripheral region 38 is defined as the remaining portion of the upper crucible surface 26. Most preferably, the central region 36 is a circular region extending around the axis of rotation A and having a diameter of up to 60% of the outer diameter of the upper crucible surface 26. The central region is preferably centered relative to the axis of rotation A. The peripheral region 38 is preferably an annular region extending around the axis of rotation A and having a dimension of 61% to 100% of the outer diameter of the crucible 18 along a direction perpendicular to the axis of rotation A.

[0065] The crucible assembly 14 further includes directional protrusions that allow setting the angular position of the crucible 18 relative to the base 22. Specifically, when the bottom surface 25 of the crucible contacts the upper surface 34 of the base and when the first alignment protrusion 30 and the second alignment protrusion 32 are engaged with each other, the directional protrusions allow the crucible 18 to be positioned relative to the base 22 at a predetermined angular orientation about the axis of rotation A. Since the base 22 is fixed to the support 20, the directional protrusions allow setting the angular position of the crucible 18 relative to the support 20.

[0066] The directional protrusions and recesses include a first directional protrusion and recess 40 formed on the base 22 and a second directional protrusion and recess 42 formed on the crucible 18. Specifically, the first directional protrusion and recess 40 is disposed on the upper surface 34 of the base and the second directional protrusion and recess 42 is disposed on the bottom surface 25 of the crucible. The first directional protrusion and recess 40 and the second directional protrusion and recess 42 are configured to be fitted together to connect the crucible 18 and the base 22. Regarding "fitted together," we mean that one of the first alignment protrusion and recess 30 and the second alignment protrusion and recess 32 can be inserted into the other.

[0067] The first directional protrusion 40 and the second directional protrusion 42 are preferably complementary in shape to facilitate the connection between the crucible 18 and the base 22. Each of the first directional protrusion 40 and the second directional protrusion 42 may be formed by a protrusion, a recess, or a combination thereof extending from the surface of the base 22 or the crucible 18.

[0068] According to a preferred embodiment, one of the first directional protrusion 40 and the second directional protrusion 42 forms a protrusion configured to fit into a recess formed by the other of the first directional protrusion 40 and the second directional protrusion 42. Preferably, the first directional protrusion 40 and the second directional protrusion 42 extend at least partially in a direction parallel to the axis of rotation A to prevent any relative rotation between the crucible 18 and the base 22 when the first directional protrusion 40 and the second directional protrusion 42 are assembled together. Most preferably, the first directional protrusion 40 forms a protrusion and the second directional protrusion 42 forms a recess. This configuration allows for a plug-and-play connection between the crucible 18 and the base 22. Furthermore, it allows for a flat crucible bottom surface 25, i.e., without protrusions, thereby improving the stability of the crucible 18 when placed on another surface.

[0069] exist Figure 6 and Figure 7 In the example shown above, the first directional protrusion 40 forms a protrusion relative to the upper surface 34 of the base, which is provided by an insert rod 41 received in a recess formed in the upper surface 34 of the base. Forming the protrusion with the insert rod 41 allows for easier fabrication of the upper surface 34 of the base by avoiding high stock removal. The second directional protrusion 42 includes a recess formed in the bottom surface 25 of the crucible. Preferably, the insert rod 41 of the first directional protrusion 40 is tightly fitted or welded into the recess formed in the upper surface 34 of the base. The insert rod 41 is also configured to have a loose fit with the recess formed in the bottom surface 25 of the crucible. In other words, the connection between the insert rod 41 and the recess formed in the upper surface 34 of the base is permanent, while the connection between the insert rod 41 and the recess formed in the bottom surface 25 of the crucible is removable. Therefore, the crucible 18 can be easily removed from the base 22 for replacement operations.

[0070] The first directional protrusion 40 and the second directional protrusion 42 preferably have a circular cross-section. Alternatively, the first directional protrusion 40 and the second directional protrusion 42 can have any shape that allows them to be assembled together so that the crucible 18 can be removably mounted on the base 22.

[0071] The second directional protrusion 42 is preferably positioned in the central region 36 of the crucible 18. In other words, the crucible 18 is arranged such that the peripheral region 38 has no directional protrusion, thereby allowing cavities 24 to be provided at a greater distance from the axis of rotation A. Therefore, with the second directional protrusion 42 located in the central region 36 of the crucible 18, more cavities 24 of a given diameter can be provided. According to this arrangement, the first directional protrusion 40 is also provided in the central region of the base 22 and aligned with the second directional protrusion 42 when the crucible 18 is attached to the base 22.

[0072] According to one embodiment, the crucible assembly 14 is configured such that the crucible 18 is first aligned along at least one direction perpendicular to the axis of rotation A, and then the orientation of the crucible 18 about the axis of rotation A is set. In other words, the crucible assembly 14 can be configured such that the alignment protrusions provided to the crucible 18 and the base 22 at least partially engage, and then the orientation protrusions begin to engage. Thus, when the crucible 18 is attached to the base 22, the crucible 18 is positioned according to at least one direction perpendicular to the axis of rotation A before any contact between the orientation protrusions. Thus, the crucible 18 is first aligned relative to the axis of rotation A and is able to rotate freely about the axis of rotation A. Then, when the first orientation protrusion 40 and the second orientation protrusion 42 engage, rotational movement of the crucible 18 is prevented so that the angular position of the crucible 18 is set. This allows the alignment and orientation functions to be performed sequentially, thereby facilitating the operator to mount the crucible 18 on the base 22.

[0073] This order is achieved because the dimension of the oriented protrusions and convexities along the rotation axis A in the crucible assembly 14 is smaller than the dimension of the aligned protrusions and convexities along the rotation axis A. Figure 7 In the preferred embodiment shown above, along the rotation axis A, the first orientation protrusion 40 is smaller than the first alignment protrusion 30.

[0074] To facilitate replacement and specifically the removal of crucible 18, crucible 18 may include a crucible handle 44 extending from the upper surface 26 of the crucible. The crucible handle 44 may include a knob 48 mounted at one end of a rod 50. Figure 4 and Figure 6 As shown, the knob 48 can be circular. Assembly of the crucible handle 44 is preferably performed by providing a hole 46 in which a rod 50 is inserted into the crucible 18. The hole 46 and the rod 50 can be connected together by a threaded connection. The crucible handle 44 is preferably located in the central region 36 of the crucible 18.

[0075] like Figure 7 As shown, the crucible 18 and the base 22 have substantially the same maximum circumferential dimension so that the circumferential side surfaces of the crucible 18 and the base 22 are substantially aligned. Furthermore, the crucible 18 and the base 22 are preferably circles with the same diameter. In other words, the crucible 18 and the base 22 each include at least one circumferential side surface aligned with each other along the axis of rotation A when the crucible 18 and the base 22 are joined together. Having the same diameter for the crucible 18 and the base 22 allows for optimized heat transfer between them (especially for cooling the crucible 18), while maximizing the usable outer diameter of the crucible 18.

[0076] The crucible assembly 14 may further include a crucible cover 52, which is intended to be positioned above the crucible 18 to cover at least one of the cavities 24. The crucible cover 52 is removably mounted to the support 20 to remain stationary relative to the crucible 18. The crucible cover 52 is configured to cover all cavities 24 not containing material at the location where they are to be bombarded by the electron beam gun. In other words, the crucible cover 52 is configured to make only one cavity accessible to the electron beam. Alternatively, the crucible cover 52 may be configured to make multiple cavities 24 accessible to the electron beam when multiple cavities 24 are positioned along the same radius relative to the axis of rotation A. The angular position of the crucible 18 allows selected cavities 24 to be positioned in front of the electron beam gun or in an operating position. The crucible cover 52 allows protection of all other cavities 24 except those in this operating position. The crucible lid 52 defines a cavity cutout or opening 54 that allows the lid 52 not to cover the cavity 24 in the operating position. The lid 52 is simply a plate having a cavity cutout 54 formed on one side to face the cavity 24 of the crucible 18. The cutout can be open, defining the outer edge of the lid 52, or closed, defining the inner edge of the lid 52. When positioned above the crucible 18, the lid 52 extends primarily perpendicular to the axis of rotation A. The lid 52 is preferably made of copper to improve heat dissipation.

[0077] The crucible lid 52 may further include a handle hole 56, configured to allow a crucible handle 44 to extend at least partially through the lid when the lid 52 is positioned above the crucible 18. In doing so, the lid 52 can be positioned very close to the crucible 18 despite the presence of the handle 44. Figure 6 and Figure 7 In the embodiment shown above, the handle hole 56 can be circular.

[0078] The crucible lid 52 may further include at least one lid handle 58 extending from the upper surface 60 of the lid. This lid handle 58 facilitates the removal and thus replacement of the crucible lid 52. In practice, the temperature of the crucible lid 52 can be very high when the material in the cavity 24 is evaporated. Preventing the operator from directly contacting the body of the crucible lid 52 is therefore safer and more comfortable. The lid handle 58 thus prevents the operator from being burned. The crucible lid 52 may include at least two lid handles 58 to further facilitate the handling of the crucible lid 52. The lid handle 58 preferably includes a knob mounted at one end of a rod. This rod is fixed to the upper surface 60 of the lid.

[0079] A further proposed method is provided for depositing a coating on surface 17 using machine 10 for physical vapor deposition as described above. This method includes a replacement operation or step for providing new material to be evaporated to crucible assembly 14. Machine 10 includes two crucibles 18, including a first crucible 18 intended for activity (i.e., set onto base 22 to perform the evaporation step), and a second crucible 18 intended for refilling (i.e., which can be cleaned and / or refilled during the evaporation step to provide new material for the next replacement operation).

[0080] First, the cavity 24 of the first crucible 18 is filled with a first set of materials. The first set of materials and their positions within the crucible 18 are determined based on the coating to be applied to the surface 17. As an example, the first antireflective coating may include the following layers listed from the surface of the coating to the outside: silicon dioxide, zircon, silicon dioxide, zircon, silicon dioxide, zircon, tin dioxide / indium tin oxide, silicon dioxide, magnesium fluoride, and magnesium oxide. The second antireflective coating may include the same layers as the first antireflective coating, and also has a silicon dioxide layer between the third zircon layer and the tin dioxide / indium tin oxide layer.

[0081] The first crucible 18 is positioned onto the base 22, which is pre-fixed to the support 20. Specifically, the first crucible 18 is connected to the base 22 such that the first alignment protrusion 30 and the second alignment protrusion 32 mate together and the bottom surface 25 of the crucible and the upper surface 34 of the base contact each other. When the crucible 18 and the base 22 include directional protrusions, the connection is performed such that the first directional protrusion 40 and the second directional protrusion 42 also mate together. Furthermore, the crucible cover 52 is then positioned above the first crucible 18 and fixed to the support 20.

[0082] The electron beam gun is then actuated to evaporate the material disposed in the cavity 24, which is in the operating position. The cavity 24 is therefore not covered by the crucible cover 52.

[0083] When a replacement operation is required, that is, when at least one material received in the first crucible 18 needs to be replaced, the crucible cover 52 is removed from the support 20. Then the first crucible 18 is removed from the base 22.

[0084] According to a preferred embodiment, a second crucible 18, comprising a second set of materials, is attached to the base 22 to replace the first crucible 18. The crucible cover 52 is then positioned and secured above the second crucible 18 to allow for another actuation step of the electron beam gun. The second crucible 18 is filled with the second set of materials prior to the replacement operation to make this replacement very quick. Most preferably, the second crucible 18 is filled and / or cleaned with the second set of materials during the actuation step of the electron beam gun to further optimize the evaporation process.

[0085] In an alternative embodiment, only one crucible 18 is used so that it can be cleaned and refilled with the second set of materials. The first crucible 18 with the second set of materials is then positioned on the base 22 to perform another actuation step of the electron beam gun.

[0086] According to an alternative embodiment, the crucible handle 44 and at least one cover handle 58 are designed as "plug-and-play" devices. Figures 9 to 11 In the illustrated embodiment, the crucible handle 44 and at least one lid handle 58 consist of a first portion 62 respectively fixed to the crucible 18 and the crucible lid 52, and a second portion 64 configured to be removably connected to the first portion 62 for handling the crucible 18 and / or the crucible lid 52. The first portion 62 includes a rod 66 fixed to the crucible 18 or the crucible lid 52. The second portion 64 includes a removable handle 68 with a control knob 70, which can be actuated to lock or unlock the removable handle 68 when the first and second portions are connected (i.e., when the rod 66 is inserted into the removable handle 68). The control knob 70 preferably includes a through-hole 72 in which the rod 66 is held when the removable handle 68 is locked. A resilient element (such as a spring) is engaged between the wall of the removable handle 68 and the control knob 70 to hold the control knob 70 in the locked position. This embodiment of the crucible handle 44 and at least one lid handle 58 allows for a significant reduction in the risk of burns to the user. In fact, during this process, the handle has been observed to be very gentle while it remains in place on crucible 18 and crucible cover 52. This removable handle embodiment allows the handle to be kept in a cool place during use of the electron beam gun and only attached to crucible 18 and / or crucible cover 52 when manipulation is required.

[0087] According to another embodiment, the crucible handle 44 and at least one cover handle 58 are... Figures 9 to 11 The embodiment is exactly the same, but a safety function is provided. This safety function is implemented by providing a reduced diameter for a portion of the rod 66, while maintaining a larger diameter at one end of the rod 66 to form an axial stop. In doing so, the control knob 70 of the second component 64 can be held in the locked position by the axial stop. The axial stop is preferably a shoulder formed on the rod 66.

[0088] The following text is for reference only. Figures 12 to 14 Alternative embodiments of the crucible assembly are described.

[0089] This alternative embodiment is consistent with the reference. Figures 3 to 7 The crucible assembly 14 described differs in that it includes an alternative arrangement of alignment and orientation protrusions on the crucible and base. This alternative arrangement is cheaper and allows for reduced manufacturing time.

[0090] Support 20 and cover 52 can be used with the crucible and base of this alternative crucible assembly.

[0091] like Figures 12 to 14 As shown, crucible assembly 80 includes a crucible 82 and a base 84 configured to receive material to be evaporated. Crucible 82 also includes a plurality of cavities 83 configured to receive material to be evaporated. The cavities 83 are formed at the upper surface 85 of the crucible, and these cavities may include all the features described with reference to crucible assembly 14 and provide all the technical effects described therewith.

[0092] The crucible 82 is configured to be connected to the base 84 such that the bottom surface 86 of the crucible makes contact with the upper surface 88 of the base.

[0093] Alignment between the base 84 and the crucible 82 is performed by a removable alignment member 90 fastened to the upper surface 88 of the base. This removable alignment member 90 protrudes from the upper surface 88 of the base and is received within an alignment cavity 92 formed within the bottom surface 86 of the crucible. The removable alignment member 90 is configured to be positioned at a central region 94 of the bottom surface 86 of the crucible. This central region 94 is defined as the central region 36 in the crucible assembly 14. The removable alignment member 90 can be fastened to the base 84 by screws 98. Alternatively, the removable alignment member 90 can be fastened to the base 84 by any fastening member. The removable alignment member 90 and the alignment cavity 92 are preferably complementary shapes. The removable alignment member 90 is preferably cylindrical.

[0094] Alternatively, this alignment arrangement can be reversed, having a removable alignment member 90 fastened to the bottom surface 86 of the crucible and an alignment cavity 92 formed in the upper surface 88 of the base.

[0095] The removable alignment component allows for easier manufacturing of the base surface 88 by avoiding high material removal rates. This reduces manufacturing time and thus manufacturing costs. The removable alignment component 90 is preferably made of stainless steel.

[0096] The crucible 82 and the base 84 are provided with additional alignment members, which include an alignment flange 100 and an alignment groove 102 intended to cooperate with each other when the crucible 82 is attached to the base 84. The alignment flange 100 is preferably disposed on the bottom surface 86 of the crucible and the alignment groove 102 is formed within the upper surface 88 of the base. Alternatively, this additional alignment arrangement can be reversed, having an alignment flange 100 disposed on the upper surface 88 of the base and an alignment groove 102 formed within the bottom surface 86 of the crucible.

[0097] These additional alignment components are located in the peripheral region 95 of the crucible 82. This peripheral region 95 is defined as the peripheral region 38 in the crucible assembly 14.

[0098] These additional alignment components provide improved alignment between crucible 82 and base 84.

[0099] The crucible 82 and base 84 are further provided with directional members, including an insertion rod 104 received in a fastening recess 106 formed in the upper surface 88 of the base, and a directional recess 108 formed in the bottom surface 86 of the crucible and configured to receive the insertion rod 104. The protrusion formed by the insertion rod 104 allows for convenient fabrication of the upper surface 88 of the base by avoiding high material removal. Preferably, the insertion rod 104 is tightly fitted or welded into the fastening recess 106. The insertion rod 104 is also configured to have a loose fit with the directional recess 108 formed in the bottom surface 86 of the crucible. In other words, the connection between the insertion rod 104 and the fastening recess 106 is permanent, while the connection between the insertion rod 104 and the directional recess 108 is removable. Therefore, the crucible 82 can be easily removed from the base 84 for replacement operations.

[0100] These directional components are located in the outer region 95 of the crucible 82.

Claims

1. A crucible assembly (14, 80) for physical vapor deposition on a surface (17), the crucible assembly comprising: - A base (22, 84) for supporting and driving a crucible (18, 82) to rotate about a rotation axis (A), the base including an upper surface (34, 88) having a first alignment protrusion (30, 90). - A crucible lid, configured to cover at least one cavity of the crucible when positioned above it. - Crucible (18, 82), the crucible comprising: • At least two cavities (24, 83) for receiving material to be evaporated onto the surface (17) by the electron beam gun, the at least two cavities (24, 83) being disposed in the peripheral region (38, 95) of the crucible (18, 82) relative to the axis of rotation (A). • A crucible bottom surface (25, 86) intended to contact the upper surface (34, 88) of the base (22, 84), the crucible bottom surface (25, 86) having a second alignment protrusion (32, 92) complementary to the first alignment protrusion (30, 90) so that when the crucible bottom surface (25, 86) contacts the upper surface (34, 88) of the base and the first alignment protrusion (30, 90) and the second alignment protrusion (32, 92) come together, the base (22, 84) and the crucible (18, 82) are aligned relative to the axis of rotation (A), the second alignment protrusion (32, 92) being disposed relative to the axis of rotation (A) at the central region (36, 94) of the crucible (18, 82); and • The upper surface of the crucible (26, 85), from which the at least two cavities (24, 83) extend; The crucible (18, 82) includes a crucible handle (44) extending from the upper surface (26, 85) of the crucible, and the crucible cover (52) has a first hole and a second hole, wherein the first hole prevents the crucible cover from covering the cavity in the operating position, and the second hole is configured to allow the crucible handle (44) to extend through the crucible cover when the crucible cover (52) is positioned above the crucible (18, 82); The crucible cover (52) includes a cover handle (58) extending from the upper surface (60) of the cover of the crucible cover (52). The crucible handle comprises a first portion fixed to the crucible and a second portion configured to be removably connected to the first portion for taking and placing the crucible; the lid handle comprises a first portion fixed to the crucible lid and a second portion configured to be removably connected to the first portion for taking and placing the crucible lid, thereby allowing the removal of the second portion of the crucible handle and the second portion of the lid handle during use of the electron beam gun, thereby keeping the second portion of the crucible handle and the second portion of the lid handle in a cold place.

2. The crucible assembly (14, 80) according to claim 1, wherein, The crucible (18, 82) includes at least ten cavities (24, 83) disposed in the peripheral region (38, 95) surrounding the axis of rotation (A).

3. The crucible assembly (14, 80) according to claim 1 or 2, wherein, The crucible (18, 82) includes an upper surface (26, 85) extending from the at least one cavity (24, 83), the upper surface (26, 85) being a circular surface centered on the axis of rotation (A) and defining an outer diameter, wherein: - The central region (36, 94) is a circular region extending up to 60% of the outer diameter around the axis of rotation (A), and / or - The outer region (38, 95) is an annular region extending 61% to 100% of the outer diameter around the axis of rotation (A).

4. The crucible assembly (14, 80) according to claim 1 or 2, wherein, The first alignment protrusion (30, 90) and the second alignment protrusion (32, 92) are one of the following: a depression formed in the surface or a protrusion protruding from the surface.

5. The crucible assembly (14, 80) according to claim 1, wherein, The upper surface (34, 88) of the base further includes a first directional protrusion (40, 104), and the bottom surface (25, 86) of the crucible further includes a second directional protrusion (42, 108), the second directional protrusion being complementary in shape to the first directional protrusion (40, 104) so ​​that when the bottom surface (25, 86) of the crucible contacts the upper surface (34, 88) of the base and the first directional protrusion (40, 104) and the second directional protrusion (42, 108) come together, the crucible (18, 82) is positioned at a predetermined angular orientation relative to the base (22, 84).

6. The crucible assembly (14, 80) according to claim 5, wherein, The second directional protrusion (42, 108) is positioned at the central region (36, 94) of the crucible (18, 80).

7. The crucible assembly (14, 80) according to claim 5 or 6, wherein, The first orientation protrusion (40, 104) is smaller in size along the rotation axis (A) than the first alignment protrusion (30, 90) along the rotation axis (A).

8. The crucible assembly (14, 80) according to claim 1 or 2, wherein, The first alignment protrusion (30, 90) and the second alignment protrusion (32, 92) provide alignment stops for the crucible (18, 82) in at least one direction perpendicular to the axis of rotation (A).

9. The crucible assembly (14, 80) according to claim 1 or 2, wherein, The base (22, 84) is disc-shaped, and the upper surface (34, 88) of the base is disposed on one side of the disc. The first alignment protrusion (30, 90) includes a protrusion centered relative to the axis of rotation (A).

10. The crucible assembly (14, 80) according to claim 1 or 2, wherein, The crucible (18, 82) is disc-shaped, with the bottom surface (25, 86) and the top surface (26, 85) of the crucible disposed on both sides of the disc, and the second alignment protrusion (32, 92) includes a recess centered relative to the axis of rotation (A).

11. A method for depositing a coating on a surface using a machine (10) for physical vapor deposition, said physical vapor deposition machine comprising: • Vacuum container (12). • At least one surface (17) to be coated, said surface being disposed within the vacuum container (12), • Crucible assembly (14, 80), which is disposed in the vacuum container (12) and has a base (22, 84) configured to cool and drive the crucible (18, 82) to rotate, the crucible assembly (14, 80) comprising first and second crucibles (18, 82) each having a plurality of cavities (24, 83) for receiving at least one material to be evaporated. • An electron beam gun, used to evaporate the at least one material. The method includes the following steps: - Provide a first set of materials and a second set of materials to the cavities (24, 83) of the first and second crucibles (18, 82), respectively. - Position the first crucible (18, 82) containing the first set of materials onto the base (22, 84). -Actuate the electron beam gun to evaporate at least one material received in the cavity (24, 83) of the first crucible (18, 82). - Remove the first crucible (18, 82) from the base (22, 84). - Position the second crucible (18, 82) containing the second set of materials onto the base (22, 84).

12. The method according to claim 11, wherein, The crucible assembly is the crucible assembly according to any one of claims 1 to 11.

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