This application claims priority to EPO Patent Application Serial No. 10174387.0, filed on Aug. 27, 20.10.
The present specification describes carriers for substrates and to methods for assembling the same in the field of vacuum deposition of thin films. In particular, a carrier for a substrate, wherein the carrier includes two frames, is described.
Thin film deposition technology plays a crucial role for production of numerous devices. In complex deposition lines it is desirable to achieve a maximum operation time, i.e. to reduce maintenance and loading times to a minimum. In this way, the efficiency of the deposition lines is increased what is of importance for industrial success of such systems.
DE 10 2005 045 718 B1 discloses a carrier for a substrate wherein at least a part of the carrier consists of a material with larger thermal expansion coefficient than the thermal expansion coefficient of the substrate, characterized in that a predetermined region of the carrier has a bridge which is centrally attached, which has a thermal expansion coefficient smaller than the region it is attached to.
DE 10 2005 045 717 B3 discloses a carrier for a substrate having two horizontal and two vertical plates.
EP 1 840 242 A1 shows an apparatus for transporting substrates through vacuum chambers, in particular coating facilities with a substrate carrier, on or at which the substrate can be attached, wherein the substrate carrier includes at least one guard rail, which extends along at least one side of the substrate carrier, and wherein the guard rail is bore spaced apart from the substrate carrier by one or several spaced apart bearings.
The present specification describes a carrier for a substrate including two frames and a method for assembling a carrier. Various embodiments of the carrier and the method are described.
In one general aspect, the carrier for a substrate to be coated in a vacuum chamber comprises a first frame comprising two vertical sections and two horizontal sections being dimensioned to surround the substrate, a second frame dimensioned to define an area of the substrate to be coated, and to cover at least a first part of the first frame to prevent the first part of the first frame from being coated when the second frame is mounted to the first frame, and wherein the second frame is detachably mounted to the first frame. In deposition processes, in particular in deposition processes including a moving substrate, any frame or other holder means may be exposed to a deposition source and coated by a deposition material forming a layer of coated material on the frame or other holder means. After a predetermined number of deposition runs, the coated material on the frame or holder may detach, hereby forming particles that migrate in a uncontrolled manner, e.g. onto the substrate or other parts of the deposition facility. These particles may have detrimental effects on the processed substrates, in cases may even destroy them. Therefore, regular cleaning of the frame or holder is required to remove the deposited material before a critical condition, e.g., a thickness of a layer of the deposited material, that results in possible detachment, is reached. Naturally, the disassembly of the frame and the cleaning causes downtime of the deposition device. The carrier comprising two frames may secure that the second frame can be readily demounted and cleaned while the first frame is partially or totally protected from being coated by the second frame. Thus, the first frame may require to be cleaned less often than the second frame. In some cases, the first frame may not be substantially coated with the result that no deposited material has to be removed at any time. Such frames may be continuously used in a deposition device without intermittent cleaning periods. Alternatively or additionally, this may facilitate that the first frame may be permanently mounted inside a deposition device as it may not be necessary to demount and clean it regularly. This may further reduce the complexity of the deposition device.
to The term “vacuum” in the context of “vacuum chamber” refers to a situation wherein a pressure inside an enclosure (e.g. a chamber) is adjusted to have any predetermined pressure below atmospheric pressure, in some instances the pressure may be lower than 300 mbar, lower than 10−3 mbar (high vacuum), or lower than 10−7 mbar (ultra high vacuum).
In other aspects, the second frame is dimensioned to prevent an edge area of the substrate from being coated.
In other aspects, the second frame comprises two vertical sections and two horizontal sections. In some aspects, the second frame may be assembled from four parts including the vertical and horizontal sections. This may be advantageous as frames assembled from different parts are believed to be more cost efficient in production than integral frames. The frames may have any predetermined size. Alternatively, the frames may be formed integrally from a single piece of a material, particularly if they are smaller than a predetermined size. As soon as the size of the frame exceeds a predetermined limit, it may be more efficient to assemble the second frame from two vertical sections and two horizontal sections. This may have the advantage that single sections can be exchanged quickly in case of a defect on said sections.
In other aspects of the carrier, the vertical sections of the first frame are of a different material than the horizontal sections of the first frame; and/or the vertical sections of the second frame are of a different material than the horizontal sections of the second frame. By having different materials in the different sections a compromise between different performance parameters of the frames can be achieved. It may be desirable, e.g., to have a carrier with high structural integrity and on the other hand employ a cheap material. In such a situation, different sections can include (e.g. be made of) different materials with predetermined properties. In such manner, different design goals can be met with respect to predetermined parameters. For instance, the vertical sections of the first frame may comprise a cheap and soft material, wherein the second frame may comprise vertical sections including a stabile and expensive material. This combination may ensure that price and mechanical properties of the carrier meet predetermined requirements. In an alternative aspect, all sections of the first and/or the second frame may comprise different materials.
In other aspects of the carrier, the first frame comprises aluminum and/or the vertical sections of the first frame comprise titanium.
In other aspects of the carrier, the second frame comprises titanium and/or the vertical sections of the second frame comprise aluminum. The combination of titanium and aluminum may be preferred as aluminum is a light, comparably inexpensive metal wherein titanium may have favorable thermal expansion properties (roughly, the thermal expansion coefficient of aluminum is three times higher than the thermal expansion coefficient of titanium). Both factors may be of increasing importance for large frames supporting large substrates (e.g. larger than 2×1 m2) where a satisfying compromise between mechanical integrity and price may be more difficult to find.
In one implementation, the vertical sections of the first frame include titanium and the horizontal sections of the first frame include aluminum and the vertical sections of the second frame include aluminum and the horizontal sections of the second frame include titanium. All sections can also be made from aluminum and titanium, respectively. This combination may provide a carrier wherein both frames comprise complementary configurations with respect to the chosen material. Therefore, when the two frames are joined, a substrate is enclosed without a gap by titanium sections. This may be advantageous in view of the different thermal expansion coefficients of aluminum and titanium. Evidently, this complementary configuration may also have said advantageous effects for other material pairs.
In other aspects, the second frame comprises stopper sections to confine the substrate in a horizontal direction. This may prevent the substrate from moving in a horizontal direction which may cause displacement or even damage of the substrate. As in some aspects the horizontal sections of the second frame comprises, or consist of, titanium which may have a low similar thermal expansion coefficient as typical substrate materials, e.g. glass, the stopper section can be attached to the second frame. When the second frame and the substrate are heated, the substrate will nevertheless remain horizontally secured by the stoppers. In carriers where the horizontal sections comprise other materials, additional measures may have to be employed. Therefore, the carriers allow for a simple and efficient design with respect to the stoppers.
In other aspects, the stopper sections are arranged at positions of the second frame suitable such that the substrate can be confined to a horizontal position at elevated temperature, especially at a temperature close to a processing temperature of the vacuum chamber, ensuring that vertical edges of the substrate are covered by the second frame. As temperatures of the processes may be high and a material the frames comprise may undergo a substantial change in geometry when being heated, it is advantageous to introduce the stopper sections in order to maintain a pre-determined configuration of the substrate inside the carrier.
In other aspects, the horizontal sections of the second frame are fixed to the first frame at or close to the middle of the horizontal extent of the horizontal sections of the first frame such that the a thermal expansion of the second frame when heated is substantially symmetrical in horizontal direction with respect to the first frame. In such manner, a well-defined expansion of the two frames may be guaranteed. In particular, if the first frame includes horizontal sections comprising aluminum and vertical sections comprising titanium and vice versa for the second frame, a substantial difference in thermal expansion of both frames in horizontal direction may occur. By fixing the horizontal sections in a central position, this difference may evolve symmetrical on both sides of the horizontal sections. This way, no unwanted asymmetries in expansion resulting in an asymmetrical or un-controlled exposition of the substrate and the frame may occur. As in some embodiments the second frame comprises stoppers in order to confine the substrate horizontally, in a worst case scenario the thermal expansion of the frames could result in an expansion that compromises the carrier's capability to affix the substrate. On the other hand, in systems with well defined expansion properties the precision and reproducibility of the fabrication process may be higher and the carrier may be designed with less material as design margins, e.g., to secure a coverage of the substrate's edges, may be reduced.
In other aspects, the vertical sections of the second frame are fixed to the first frame at or close to the middle of the vertical extent of the vertical sections of the first frame such that the a thermal expansion of the second frame when heated is substantially symmetrical in vertical direction with respect to the first frame. As in an aspect, the first frame includes horizontal sections comprising aluminum and vertical sections comprising titanium and vice versa for the second frame, a substantial difference in thermal expansion of both frames in vertical may occur. A fixation close to the middle of the vertical sections thus has the same advantages as explained above in connection with the fixation of the horizontal sections.
In other aspects, the second frame is detachably mounted to the first frame using keyhole bolt joints. This feature may allow a quick mounting of the second frame onto the first frame.
In other aspects, the second frame comprises bolts at a side facing the first frame, the bolts designed to engage with corresponding keyhole openings in the first frame.
In other aspects, the keyholes are designed to allow movement of the corresponding bolts in an engaged position. This feature is advantageous in particular in systems where the frames, or sections of the frames undergo substantial thermal expansion in the temperature ranges occurring during a deposition process.
In other aspects, the keyholes are designed such that the movement of the corresponding bolts in the engaged position is more limited in a first spatial direction, especially in the vertical direction, than in a second spatial direction, especially in the horizontal direction, the first and second spatial directions are both in a plane substantially parallel to the first frame.
In other aspects, the keyholes are designed to take a relative movement of the first frame with respect to the second frame caused by thermal expansion when being heated from a first temperature to a second temperature into account. The second temperature can be a processing temperature of the vacuum chamber.
In other aspects, the keyhole bolt joints are designed, e.g., by keyholes formed with a chamfer, to pull the second frame towards the first frame when mounting the second frame to the first frame. In such a configuration, the second frame may be merely suspended to the first frame via appropriately positioned keyholes and bolts. This allows a very effective mounting and demounting of the first frame, as the processes may be carried out solely by moving the first frame without requiring further tools. This further reduces the down-time of the deposition line.
In other aspects, the first frame may be mounted to the second frame by suspension. The first and second frames may comprise corresponding means that facilitate the suspension.
The keyholes, in particular when additionally being configured to allow a relative movement of the first frame with respect to the second frame in a first direction and limit it in a second direction, may be of particular use if the frames comprise sections including different materials. In some aspects, different materials having different thermal expansion coefficients, e.g. titanium and aluminum may be employed in the vertical and horizontal sections of the first and/or second frame. Then, a configuration with keyholes each allowing a relative movement of the first frame with respect to the second frame in a first direction and limit it in a second direction may have a particularly advantageous effect in securing a well-defined expansion behavior of the carrier. In other aspects, the carrier further comprises clamping means supported by the first frame and suitable to fix the substrate by clamping against the second frame. In some aspects, these clamping means are arranged at a surface of the first frame facing away from the deposition source and engage with a surface of the substrate facing away from the deposition source. Thus, any diminishment of the area of the substrate to which a coating may be applied on by the deposition facility may be avoided. This enhances the yield of the deposition facility as waste of substrate area that is potentially available to deposit films thereon is avoided.
In other aspects, the horizontal sections of the first frame comprise horizontal slots to reduce thermal deformation of outer parts of the horizontal sections. In some deposition devices, heating elements may be arranged collinear with the vertical sections of the first and second frames and extending substantially parallel to a vertical extension of a substrate. This may result in a stronger heating of inner parts of the horizontal sections and a weaker heating of outer parts. The vertical sections, particularly if the substrate is moved in a horizontal direction, may be heated more homogeneously than the horizontal sections. Thus, it may be advantageous to reduce thermal coupling between said inner and outer parts of the horizontal sections. In addition, the substrate may be substantially heated during the deposition process. Thus, any parts of the first frame in direct contact with the substrate may itself exhibit more heating due to the thermal contact with the hot substrate. As the horizontal sections of the first frame may be thermally conductive it may be advantageous to reduce thermal coupling between said parts in thermal contact with the substrate and the outer parts of the horizontal sections.
In other aspects, a surface of the second frame which is exposed to coating in a vacuum chamber comprises surface patterned sections, especially waffle-patterned sections, especially wherein only the vertical sections of the second frame comprise the surface patterned sections. A patterned surface may increase the surface of the sections and may also increase the amount of coating material that can be deposited onto the section before adverse detachment effects occur. This way, the number of deposition runs for the first frame without cleaning may be increased.
Other aspects include a method for assembling a carrier, e.g., any of the carriers described above, for a substrate to be coated in a vacuum chamber comprising the steps of providing a first frame, providing a second frame, removably mounting the second frame to the first frame prior to mounting a substrate to the carrier, wherein the second frame is dimensioned to define an area of the substrate to he coated, and to cover at least a first part of the first frame to prevent the first part of the first frame from being coated when the second frame is mounted to the first frame.
Further aspects of the methods include that the second frame is dimensioned to prevent an edge area of the substrate from being coated.
Further aspects of the methods include that mounting the second frame to the first frame includes using keyhole bolt joints.
Further aspects of the methods include, wherein the keyhole bolt joints are designed, e.g., using keyholes formed with a chamfer, to pull the second frame towards the first frame when mounting the second frame to the first frame.
Further aspects of the methods further comprise that:
Further aspects of the methods further comprise that:
Further aspects of the methods include that the second frame is fixed to the first frame such that a relative movement of the first frame with respect to the second frame caused by thermal expansion when being heated from a first temperature to a second temperature. The second temperature can be a processing temperature of the vacuum chamber and controlled by the fixing of the second frame to the first frame.
a-c shows a schematic drawing of keyholes.
In
The terms horizontal and vertical sections refer to a configuration in a vertical deposition device. In such a configuration, the deposition device may be configured to house and process the substrate in a substantially vertical position. This means that the extended surfaces of the substrate are substantially coplanar to the direction of the force of gravity. In such a device the carrier and herewith the first and second frames will have substantially the same orientation as the substrate. Therefore, the elongated sections forming each frame can be classified as vertical and horizontal sections, wherein “vertical” refers to the sections located on the parts of the frame extending substantially parallel to the direction of the force of gravity and “horizontally” refers to sections located on the parts of the frame extending substantially orthogonal to the direction of the force of gravity. However, all carriers and methods for assembling carriers can be equally applied in deposition devices housing and processing substrates in a substantially horizontal manner and also in all intermediate configurations between horizontal and vertical deposition devices. In a horizontal deposition device where all parts of the frames extend substantially in a horizontal plane one pair of sides of the frames may be labeled “horizontal” and the other pair “vertical”.
The term “detachably mounted” includes all situations where the first frame is attached to the second frame by any releasable means. In some embodiments, this may include attachment devices that facilitate manual or tool assisted mounting and release of the first frame from the second frame, e.g. by means of screws, clamps or clips. The term “detachably mounted” is, however, not limited to these embodiments.
In some embodiments, the first 3 and second 2 frames have a substantially rectangular outer shape. Furthermore, the second frame 2 and/or the first frame 3 can define an open inner area. The first frame 3 may also include a closed inner area so that no opening is formed. A rectangular frame is usually formed from four extended sections. The sections can have a predetermined cross-section and extend in a predetermined direction. In a vertical deposition device, e.g. a device housing and processing a substrate in a substantially vertical fashion, two of the sections have their direction of extension in a substantially vertical direction and the remaining two in a horizontal direction. In
In
In
The choice of the material for the frames is also a question of design that has to be answered for every specific substrate size and deposition type. However, there are preferential configurations and material choices. Usually, the first 3 and second 2 frames will comprise, or consist of, a metal. Preferred metals are metals comprising iron and iron alloys, such as stainless steel, aluminum or aluminum alloys or titanium or titanium alloys.
The materials of the vertical sections 32 and horizontal sections 31 of the first frame 3 can include, or consist of, different materials. It may be prohibitive to manufacture the entire first frame from a first material due to price, weight or other restrictions. In such cases the vertical sections 32 can include or consist of the first material, wherein the horizontal sections 31 include or consist of a second material. In some frames the first material is titanium and/or the second material is aluminum.
In
In addition or alternatively, fixation means can be employed along a vertical direction of the vertical sections 22, 32 of the first and second frame 2, 3. This fixation means can be placed in the upper third of the vertical sections 22, 32. Said fixation means can also be combined with other devices for mounting the second frame onto the first, in particular with the keyhole joints described in more detail below.
The first frame 3 and second frame 2 can be assembled by using different mounting schemes. In some cases the second frame 2 may be firmly mounted on the first frame 3 at predetermined positions by connectors, such as screws or bolts, or the second frame 2 may be clipped or clamped to the first frame 3 by suitable means. For instance, a predetermined number of screws can be positioned circumferentially about the first frame 3 and second frame 2 to firmly mount the second frame 2 onto the first frame 3. However, particularly in cases where the carrier is used under varying process temperatures (e.g. a first temperature when the carrier is assembled and a second temperature during deposition), other mounting schemes may be advantageous. This is even more the case as some carriers employ different materials, e.g. aluminum and titanium, with different thermal expansion coefficients in different sections of the first and second frames. In such carriers, the relative position of a first point located on the first frame and a second point located on the second frame may alter when the assembled carrier is heated. In an exemplary carrier the horizontal sections of the first frame may comprise, or consist of, aluminum and the horizontal sections of the second frame may comprise, or consist of, titanium. Thus, the horizontal sections of the first frame may have a larger thermal expansion. Therefore, the first and second frames can be equipped with suitable mounts that may have a play in directions so that the differences in thermal expansion of the first and second frame can be tolerated. Some carriers may be provided with fixation means located in the region of the center of the horizontal extent of the horizontal sections and/or close to the center of the vertical extent of the verticals sections. This configuration may secure that relative thermal movement of the second frame with respect to the first frame when heated is substantially symmetrical in a horizontal and/or vertical direction. In general, the frames may expand during heating herewith increasing the area of the substrate exposed to the deposition source. By having a symmetrical movement of the second frame with respect to the first frame also the exposed area on the substrate may be symmetrical in the horizontal and/or vertical direction.
a depicts an exemplary recession 61 configured to mount the second frame to the first frame in combination with a corresponding screw or bolt (not shown). For instance, the recession 61 could be positioned at a circumferential position about the first frame and the second frame could comprise a bolt or screw hole at a corresponding position. As can be seen from
b shows a detailed view of an alternative mounting recession in form of a keyhole 62 for mounting the second frame to the first frame. In such cases, the carrier may also be equipped with corresponding mounting bolts or screws. For instance, the bolts may be arranged circumferential about the second frame and the keyholes at corresponding positions at the first frame. The keyholes also have an elongated section 623 that allows the movement of the second frame with resped to the first frame in a first direction and limits the movement in an orthogonal second direction. The two directions may be aligned parallel to the horizontal and vertical sections, or vice versa. It may be also advantageous to allow a movement in a direction substantially in the plane of the first and second plane forming an angle with respect to the horizontal or vertical directions. Furthermore, the keyhole 62 of
The substrate is affixed to the carrier by employing a clamp system. In
Even though the exemplary carrier of
The second frame 2 can be beveled at an inner region of the second frame 2 next to the substrate 7. In
In
Furthermore, the surface 200 of the second frame 2 exposed to the deposition source may include patterned sections (not shown in
In some methods for assembling the carrier the mounting of the second frame to the first frame is done by using keyhole bolt joints as described above. In such cases, in particular when the keyholes comprise chamfers, the second frame may just be suspended to the first frame by engaging the bolts to the keyholes. By virtue of the chamfers the second frame may be then pulled towards the first frame. The vertical and the horizontal sections of the second frame may be joined before mounting it to the first frame or alternatively after the vertical and horizontal sections of the second frame have been mounted to the first frame.
As an alternative to the claims, the subject matter of this specification may be defined by any of the following embodiments:
Embodiment 1 is directed to a Carrier (1) for a substrate to be coated in a vacuum chamber comprising;
a first frame (3) comprising two vertical sections (32) and two horizontal sections (31) being dimensioned to surround the substrate;
a second frame (2) dimensioned
wherein the second frame (2) is detachably mounted to the first frame (3).
Embodiment 2 is directed to the carrier of embodiment 1, wherein the second frame (2) is dimensioned to prevent an edge area of the substrate from being coated.
Embodiment 3 is directed to the carrier of embodiment 1 or 2, wherein the second frame (2) comprises two vertical sections (22) and two horizontal sections (21).
Embodiment 4 is directed to the carrier of any of embodiments 1 to 3, wherein the vertical sections (32) of the first frame (3) are of a different material than the horizontal sections (31) of the first frame (3); and/or wherein the vertical sections (22) of the second frame 2) are of a different material than the horizontal sections (21) of the second frame (2).
Embodiment 5 is directed to the carrier of embodiment 4, wherein the horizontal sections (31) of the first frame (3) comprise Aluminum and/or the vertical sections (32) of the first frame (3) comprise Titanium.
Embodiment 6 is directed to the carrier of embodiment 4 or 5, wherein the horizontal sections (21) of the second frame (2) comprise Titanium and/or the vertical sections (22) of the second frame (2) comprise Aluminum.
Embodiment 7 is directed to the carrier of any of embodiments 1 to 6, wherein the second frame (2) comprises stopper sections (9) to confine the substrate in a horizontal direction.
Embodiment 8 is directed to the carrier of embodiment 7, wherein the stopper sections (9) are arranged at positions of the second frame (2) suitable such that the substrate can be confined to a horizontal position at elevated temperature, especially at a temperature close to a processing temperature of the vacuum chamber, ensuring that vertical edges of the substrate are covered by the second frame (2).
Embodiment 9 is directed to the carrier of any of embodiments 1 to 8, wherein the horizontal sections (21) of the second frame (2) are fixed to the first frame (3) at or close to the middle of the horizontal extent of the horizontal sections (31) of the first frame (3) such that the a thermal expansion of the second frame (2) when heated is substantially symmetrical in horizontal direction with respect to the first frame (3).
Embodiment 10 is directed to the carrier of any of the embodiments 1 to 9, wherein the vertical sections (22) of the second frame (2) are fixed to the first frame at or close to the middle of the vertical extent of the vertical sections (32) of the first frame (3) such that the a thermal expansion of the second frame (2) when heated is substantially symmetrical in vertical direction with respect to the first frame (3).
Embodiment 11 is directed to the carrier of any of the embodiments 1 to 10, wherein the second frame (2) is detachably mounted to the first frame using key-hole bolt joints.
Embodiment 12 is directed to the carrier of embodiment 11, wherein the second frame (2) comprises bolts at a side facing the first frame (3), the bolts designed to engage with corresponding keyhole (62) openings in the first frame (3).
Embodiment 13 is directed to the carrier of embodiment 11 or 12, wherein the keyholes (62) are designed to allow movement of the corresponding bolts in an engaged position.
Embodiment 14 is directed to the carrier of embodiment 13, wherein the keyholes (62) are designed such that the movement of the corresponding bolts in the engaged position is more limited in a first spatial direction, especially in the vertical direction, than in a second spatial direction, especially in the horizontal direction, the first and second spatial directions are both in a plane substantially parallel to the first frame.
Embodiment 15 is directed to the carrier of embodiment 14, wherein the keyholes are designed to take a relative movement of the first frame (3) with respect to the second frame (2) caused by thermal expansion when being heated from a first temperature to a second temperature into account. The second temperature can be a processing temperature of the vacuum chamber.
Embodiment 16 is directed to the carrier of any of the embodiments 11 to 15, wherein keyhole bolt joints are designed, e.g., by keyholes (62) formed with a chamfer (622), to pull the second frame (2) towards the first frame (3) when mounting the second frame (3) to the first frame (2).
Embodiment 17 is directed to the carrier of any of embodiments 1 to 16, further comprising clamping means (8) supported by the first frame (3) and suitable to fix the substrate by clamping against the second frame (2).
Embodiment 18 is directed to the carrier of any of embodiments 1 to 17, wherein the horizontal sections (31) of the first frame (31) comprise horizontal slots to reduce thermal deformation of outer parts of the horizontal sections (31).
Embodiment 19 is directed to the carrier of any of embodiments 1 to 18, wherein a surface (200) of the second frame (2) which is exposed to coating in vacuum chamber comprises surface patterned sections, especially waffle-patterned sections, especially wherein only the vertical sections (22) of the second frame (2) comprise the surface patterned sections.
Embodiment 20 is directed to a method for assembling a carrier, e.g., the carrier according to any of embodiments 1 to 19, for a substrate to be coated in a vacuum chamber comprising the steps of:
providing a first frame (1001),
providing a second frame (1002),
removably mounting the second frame to the first frame prior to mounting a substrate to the carrier (1003);
wherein the second frame is dimensioned
Embodiment 21 is directed to the method of embodiment 20, wherein the second frame is dimensioned to prevent an edge area of the substrate from being coated.
Embodiment 22 is directed to the method of embodiment 20 or 21, wherein mounting the second frame to the first frame includes using keyhole bolt joints.
Embodiment 23 is directed to the method of embodiment 22, wherein the keyhole bolts joints are designed, e.g., using keyholes formed with a chamfer, to pull the second frame towards the first frame when mounting the second frame to the first frame.
Embodiment 24 is directed to the method of any of embodiments 20 to 23, further comprising: preassembling the second frame before the second frame is mounted to the first frame, wherein preassembling the second frame comprises joining vertical sections and horizontal sections of the second frame.
Embodiment 25 is directed to the method of any of embodiments 20 to 23, wherein removably mounting the second frame to the first frame further comprises: mounting predetermined parts of the second frame separately to the first frame, mounting vertical sections and horizontal sections of the second frame separately to the first frame.
Embodiment 26 is directed to the method of any of embodiments 20 to 25, further comprising: fixing the second frame to the first frame, especially by using one or more screws.
Embodiment 27 is directed to the method of embodiment 26, wherein the second frame is fixed to the first frame such that a relative movement of the first frame with respect to the second frame caused by thermal expansion when being heated from a first temperature to a second temperature. The second temperature can be a processing temperature of the vacuum chamber and controlled by the fixing of the second frame to the first frame.
Number | Date | Country | Kind |
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10174387.0 | Aug 2010 | EP | regional |