Heating device

Abstract

The invention relates to a heating device (1) having a heating plate (2) for heating a workpiece (3), in particular a wafer, in a vacuum chamber (4), the heating plate (2) having a carrier layer (5) with an upper side (6) on or above which the workpiece (3) can be arranged for heating, and having a heating element (7) for heating the workpiece (3) in the vacuum chamber (4). The invention relates to a heating device (1) for heating a carrier layer (5) of a heating plate (2) in a vacuum chamber (4), the heating device (1) having fastening arms (9) arranged on an edge (8) of the heating plate (2) for fastening the heating plate (2) to a carrier bracket (10) in the vacuum chamber (4), the fastening arms (9) each having at least one elastically deflectable spring element (11) and a fastening device (12), the fixing device is used for fixing the corresponding spring element (11) on the corresponding bearing support (10).

Description

Field of the Invention

[0001] The present invention relates to a heating device according to the preamble of claim 1 and to a vacuum chamber having such a heating device. Background Art

[0002] This type of heating device is known in the prior art. The heating device is used to heat a workpiece, such as a wafer, so that it is at a temperature required, for example, in a subsequent processing step. US 6,551,448 B2 describes a heating device having a heating plate for heating a workpiece. Summary of the Invention

[0003] The object of the present invention is to improve a heating device of this type such that the heating device can compensate particularly effectively for the thermal dimensional changes of the heating plate without generating undesired thermal stresses in the heating plate.

[0004] To achieve this object, the present invention provides a heating device according to claim 1.

[0005] According to the invention, it is provided that the heating device has fixing arms arranged on the edge of the heating plate for fixing the heating plate to a carrier bracket in a vacuum chamber, wherein each fixing arm has at least one elastically deflectable spring element and a fixing means for fixing the respective spring element to the respective carrier bracket.

[0006] The thermal dimensional changes of the heating plate can be compensated by the fixing arms arranged on the edge of the heating plate and in particular by their elastically deflectable spring elements without generating undesired stresses in the heating device. The elastically deflectable spring elements are advantageously configured to extend longitudinally. The elastic deflection of the spring element advantageously takes place transversely to its longitudinal extension. Particularly preferably, the elastically deflectable spring elements of the fixing arms are each configured as leaf springs. However, in principle, elastically deflectable spring elements of different configurations can also be provided. Particularly preferably, the elastically deflectable spring element is fixed at one end to the edge of the heating plate, while the fixing means of the respective fixing arm is at the opposite end. Particularly preferably, it is provided that the spring element can be elastically deflected in a deflection plane extending parallel to the upper surface of the carrier layer. However, it is also advantageous if the fixing arm projects outward from the heating plate. Each fixing arm can have exactly one elastically deflectable spring element and exactly one fixing means. However, the following variant can also be considered, in which the fixing arm has two elastically deflectable spring elements, both of which are connected to the same fixing means. Generally, each fixing arm can have a plurality of elastically deflectable spring elements and / or a plurality of fixing means.

[0007] There are also different possibilities for the design of the fixing device. In a particularly simple design, the fixing device is a fixing hole, and the bearing bracket itself or, for example, a fixing member such as a bolt or a rivet can be guided through the fixing hole in order to fix the fixing device to the bearing bracket. However, the fixed connection can also be implemented, for example, as a clamping connection, a bolt connection, and similar connections.

[0008] The fixing arm can be implemented in one piece or also in multiple pieces. The fixing arm or its elastically deflectable spring element can be integrally formed on the heating plate. However, it is also conceivable that the fixing arm or its elastically deflectable spring element is first manufactured as a separate component and then fixed to the heating plate in a suitable manner, such as by screwing, riveting, soldering, welding, and similar methods. This also applies to the connection between the elastically deflectable spring element and the fixing device.

[0009] In order to perform the compensation for the dimension changes caused by heat, it is particularly preferably provided that the spring elements each have a spring stiffness in the range of 30 N / mm to 100 N / mm, preferably 50 N / mm to 80 N / mm. The spring constant represents, as is commonly known, the ratio of the force acting on the spring element to the resulting deflection of the spring element. The deflection is advantageously measured in a direction orthogonal or radial to the adjacent edge of the heating plate.

[0010] There are different possibilities for the design of the heating element to heat the bearing layer of the heating plate and thus also the upper surface of the bearing layer. A particularly preferred variant of the present invention provides that the heating element is configured in a planar manner and is arranged in contact with the bearing layer on the side of the bearing layer opposite to the upper surface. The heating element can be, for example, a known thick-film heating device, in which the electrical heating element is arranged in a planar manner between two glass plates. This sandwich-structured heating element advantageously comes into direct planar contact with the side of the bearing layer facing away from the upper surface.

[0011] The heating plate can consist only of the bearing layer or can also be constructed in multiple layers, that is, for example, when the heating element is also constructed as an additional layer fixed to the bearing layer of the heating plate.

[0012] How advantageous it is that the heating element is an electrically operated heating element. A particularly preferred variant provides that the power supply line of the heating device is guided to the heating element through at least one outwardly sealed pipe. Thereby, the electrical connection points for connecting the power supply line to the heating element can always be kept at atmospheric pressure, which helps to avoid electrical flashover phenomena caused by applying a vacuum in the vacuum chamber. The outwardly sealed pipe can be directly guided to the heating element or lead to an outwardly sealed connection chamber in which the electrical connection points of the heating element are located.

[0013] The carrier layer is preferably made of steel. However, the carrier layer can also be made of aluminum alloy or other correspondingly heat-conductive materials.

[0014] The workpiece to be heated can be placed directly on the upper surface of the carrier layer of the heating plate or arranged at a certain distance above the upper surface of the carrier layer of the heating plate during the heating process.

[0015] It is possible that the heating plate has notches for the lifting arms to pass through, and the lifting arms are used to lift the corresponding workpiece from the upper surface of the carrier layer of the heating plate or to hold the corresponding workpiece above the upper surface of the carrier layer of the heating plate. In the case where the workpiece is arranged at a certain distance above the upper surface of the carrier layer during the heating process, the workpiece can be placed on the lifting arms, for example. Particularly preferably, the lifting arms are equipped with support balls preferably made of glass, and the workpiece can be placed on the support balls.

[0016] The workpiece to be processed is advantageously plate-shaped. The workpiece can in particular be the aforementioned wafer.

[0017] The temperature generated by the heating element in the carrier layer and especially on the upper surface of the carrier layer is advantageously regulated by a corresponding temperature regulating device. In this sense, it is advantageous that the heating device has at least one temperature sensor for measuring the temperature of the carrier layer of the heating plate. The temperature value can then be fed as a measured value to the regulating device of the heating element.

[0018] In addition to the heating device, the present invention also relates to a vacuum chamber having at least one heating device according to the present invention, wherein the vacuum chamber has a substrate and preferably at least three carrier brackets protruding from the substrate and arranged at intervals from each other, and the heating plate of at least one heating device is preferably fixed to the carrier brackets only by the fixing device of the fixing arm. The vacuum chamber can be a rough vacuum chamber, an intermediate chamber, or a process chamber. Particularly preferably, the vacuum chamber is a rough vacuum chamber, and the workpiece to be processed is placed in the rough vacuum chamber under atmospheric pressure and then a corresponding negative pressure is generated in the closed vacuum chamber, wherein the workpiece can be heated by the heating device simultaneously or subsequently. However, the vacuum chamber according to the present invention can of course also be a process chamber, in which other processing processes are performed on the workpiece in addition to heating the workpiece.

[0019] Generally, a vacuum chamber is used when working in a specific atmosphere and / or at a specific low pressure level. In particular, when working under conditions where the pressure level is less than or equal to 0.001 mbar (millibar), i.e., 0.1 Pascal, it can be particularly regarded as a vacuum chamber. However, when the vacuum chamber is designed for a pressure level lower than normal pressure, i.e., lower than 1 bar, it can also be regarded as a vacuum chamber.

[0020] A single heating device with a single heating plate can be arranged in the vacuum chamber. However, it is just possible to arrange the heating plates of two or more heating devices one above the other in the vacuum chamber. Vacuum valves for opening and closing the vacuum chamber and transport devices for inserting and removing workpieces into or from the vacuum chamber are known in the prior art and do not need to be explained further here.

[0021] It is preferably provided that the fixing arms provided according to the invention are used not only to compensate for the dimensional changes of the heating plate caused by heat, but also to ensure the thermal insulation of the heating device relative to the substrate of the vacuum chamber. It is advantageously provided that during heating by means of the at least one heating device, there is a temperature difference of at least 100 degrees Celsius, preferably at least 200 degrees Celsius, between the substrate and the carrier layer of the heating plate of the at least one heating device. In order to achieve the above values, the fixing arms and in particular the elastically deflectable spring elements can have a correspondingly small cross section and / or be composed of a correspondingly suitable thermal insulation material. There are a number of possibilities for achieving this, which can be configured by a person skilled in the art according to requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features and details of the preferred configuration of the present invention are explained below by way of example with reference to an embodiment. In the drawings:

[0023] Figure 1 A schematic longitudinal section through a vacuum chamber according to the invention is shown, which has two heating devices according to the invention arranged one above the other;

[0024] Figure 2 The stereogram shows the Figure 1 The two heating devices;

[0025] Figure 3 Show according to Figure 2 A top view of the arrangement;

[0026] Figure 4 Show Figure 2 An exploded view of

[0027] Figure 5 Shown along the Figure 3 Cross-sectional view taken along the cutting line AA. DETAILED DESCRIPTION

[0028] Figure 1The longitudinal sectional view of the segmented vacuum chamber 4 shown is highly schematic. Only the substrate 18 and a cross-sectional view of the remaining housing are visible from the vacuum chamber. Vacuum valves for placing the workpiece 3 into the vacuum chamber 4 and removing it from the vacuum chamber 4, such as a possible evacuation device, a processing device, etc., are also not shown. The components not shown here can be implemented as known in the prior art. This also applies to the loading robot that places the workpiece 3 into the vacuum chamber 4 and also removes it from the vacuum chamber.

[0029] In Figure 1 two heating devices 1 according to the invention arranged one above the other can be seen, which heating devices have their heating plates 2. Each heating plate 2 has a bearing layer 5 with an upper surface 6. A workpiece 3, which is implemented as a wafer, for example, is placed directly on the respective upper surface 6 of the respective bearing layer 5 or is arranged at a certain distance above the upper surface 6 of the bearing layer 5 for heating. The bearing layer 5 is always heated by heating elements 7. In this example, the heating elements 7 are the thick-film heating devices already mentioned at the beginning and known. The heating elements 7 are each configured in a planar manner and are arranged on the bearing layer 5 of the respective heating plate 2 on the side opposite to the upper surface 6 in a manner that abuts against the bearing layer 5. In addition to the heating device 1, Figure 1 also shown is a lifting drive plate 19 arranged in the vacuum chamber, which can be raised and lowered by a known lifting drive device 20, which is only schematically shown here, and a lifting arm 16 is constructed on the lifting drive plate. The lifting drive device 20 can raise and lower the lifting arm 1 together with the lifting drive plate 19. The lifting arm 16 is also used to place the workpiece 3 on the upper surface 6 of the bearing layer 5 and to raise it again from the upper surface. If the workpiece 3 should be placed directly against the upper surface 6 of the bearing layer 5 during the heating process, then this placement is carried out. If the workpiece 3 is arranged at a certain distance above the upper surface 6 of the bearing layer 5 during the heating process, then the workpiece can be placed against the lifting arm 16 at a corresponding distance from the upper surface 6 during the heating process. It is particularly preferably provided that each of the lifting arms 16 has at least one ball 21, preferably made of glass, as will be shown later, and the workpiece 3 is supported on the ball. In Figure 1 also shown is a bearing bracket 10 on which the heating plate 2 is fixed by its fixing arm 9 as will be described in more detail later.

[0030] Furthermore, in Figure 1 also shown is a pipe 15 through which a power supply line 14 for the heating element 7, which is designed as an electric heating element here, of the respective heating device 1 is guided.

[0031] In accordance with Figure 2In the perspective view, the upper part of the vacuum chamber 4 is now removed, so that only the substrate 18, the carrier bracket 10 fixed to the substrate, and the heating device 1 having a heating plate 2 and fixed to the carrier bracket 10 are still visible.

[0032] It is at least provided according to the present invention that each heating device in the heating device 1 has a fixing arm 9 arranged on the corresponding edge 8 of the heating plate 2, and the fixing arm is used to fix the corresponding heating plate 2 to the carrier bracket 10 in the vacuum chamber 4. Each fixing arm 9 respectively has at least one elastically deflectable spring element 11 and a fixing device 12 for fixing the corresponding spring element 11 to the corresponding carrier bracket 10. The elastically deflectable spring element 11 is preferably respectively constructed as a leaf spring extending longitudinally as shown here. In the embodiment shown here, the elastically deflectable spring element 11 is respectively integrally formed on the corresponding edge of the corresponding heating plate 2. The fixing device 12 is located at the corresponding opposite end of the spring element, and the fixing device is implemented as a simple fixing ring in this embodiment. Of course, other types of fixing devices 12 can also be realized to fix the corresponding fixing arm 9 and thus the corresponding heating plate 2 to the corresponding carrier bracket 10. This can be, for example, a clamping connection or a bolt connection or other types of fixing. For fixing the fixing arm 9 or the elastically deflectable spring element 11 to the corresponding edge 8 of the corresponding heating plate 2, there are of course possibilities different from the embodiment shown here. Instead of the integral formation of the fixing arm 9 or the elastically deflectable spring element 11, the components can also be fixed to the corresponding edge of the corresponding heating plate 2 by bolt connection, riveting, brazing, welding and / or in other ways. Figure 2 It is also shown that the fixing arm 9 can be constructed differently. As Figure 2 The fixing arm 9 shown in the lower right corner respectively has a single elastically deflectable spring element 11, and a single fixing device 12 is correspondingly located at the end of the spring element facing away from the edge 8 of the corresponding heating plate 2. In Figure 2 A variant of the fixing arm 9 is shown in the upper left corner, where the fixing device 12 is arranged between and fixed to two elastically deflectable spring elements 11. There are different possibilities for this. It should be particularly noted that the elastically deflectable spring element 11 is more or less straight, can also be slightly curved, but can also be designed to have a more rounded or curved orientation significantly stronger than that shown here.

[0033] At least as implemented here, it is advantageously provided that the spring element 11 can be elastically deflected respectively on a deflection plane 13 extending parallel to the upper surface 6 of the carrier layer 5. The position of the deflection plane 13 is schematically shown in Figure 1 It is also advantageous that, as also implemented here, the fixing arm 9 projects outward from the heating plate 2 respectively.

[0034] In Figure 2 the measuring sensor 17 can also be seen, which is used to measure the temperature of the bearing layer 5 of the corresponding heating plate 2 and is respectively arranged on the corresponding bearing layer 5.

[0035] For the sake of completeness, it is pointed out here again that in the vacuum chamber 4 according to the invention, only a single heating device 1 according to the invention can be correspondingly arranged, however, two or more heating devices 1 according to the invention can also be arranged. If two or more heating devices 1 according to the invention are involved, the heating devices are advantageously arranged one above the other in the vacuum chamber 4 as also shown here.

[0036] In Figure 2 each upper surface 6 of the corresponding bearing layer 5 of the corresponding heating plate 2, the workpiece 3 is placed thereon. Here, for example, a wafer or other plate-shaped workpiece 3 can be used. However, the workpiece 3 is not shown in the top view according to Figure 3 It can be clearly seen here that, as also in the exploded view according to Figure 4 each heating plate 2 has a notch 22 for the lifting arm 16 to pass through. In Figure 3 the balls 21 in the lifting arm 16 can also be seen. The balls are preferably glass balls. It is advantageously provided that the workpiece 3 is placed on the lifting arm 16 only when there are balls 21 in between. If the lifting arm 16 is correspondingly lowered substantially by the lifting drive device 20, the workpiece 3 directly abuts against the upper surface 6 of the bearing layer 5.

[0037] Figure 4 The arrangement according to Figure 2 is shown again in an exploded view, in which the above-mentioned details can be seen particularly well.

[0038] Figure 5 Shows a cross-sectional view of the outwardly sealed duct 15 provided here along the cutting line A-A from Figure 3 The power supply line 14 for operating the corresponding electrically operated heating element 7 is guided through the duct. In Figure 5 it can be seen how the power supply lines 14 are respectively connected to the electric heating elements 7 by means of the electrical connection points 24. In Figure 5 the electrical connection points 24 are located in the outwardly sealed connection cavity 25 into which the outwardly sealed duct 15 is introduced.

[0039] However, alternatively, the duct 15 can also be directly guided to the electrical connection point 24, so that the corresponding connection cavity 25 can also be omitted.

[0040] For the sake of completeness, it should also be noted that the section of the pipe 15 can also be configured as a corrugated hose 23 as shown here. The thermal expansion and displacement of the pipe 15 can be compensated by means of the corrugated hose 23.

[0041] List of reference numerals

[0042] 1 Heating device

[0043] 2 Heating plate

[0044] 3 Workpiece

[0045] 4 Vacuum chamber

[0046] 5 Bearing layer

[0047] 6 Upper surface

[0048] 7 Heating element

[0049] 8 Edge

[0050] 9 Fixed arm

[0051] 10 Bearing bracket

[0052] 11 Spring element

[0053] 12 Fixing device

[0054] 13 Offset plane

[0055] 14 Power supply line

[0056] 15 Pipe

[0057] 16 Lifting arm

[0058] 17 Temperature sensor

[0059] 18 Substrate

[0060] 19 Lifting drive plate

[0061] 20 Lifting drive device

[0062] 21 Ball

[0063] 22 Notch

[0064] 23 Corrugated hose

[0065] 24 Electrical connection point

[0066] 25 Connection chamber.

Claims

1. A heating device (1) having a heating plate (2) for heating a workpiece (3), in particular a wafer, in a vacuum chamber (4), wherein, the heating plate (2) has a carrier layer (5), the carrier layer has an upper side (6), the workpiece (3) can be arranged on or above the upper side for being heated, and the heating device (1) has a heating element (7) for heating the carrier layer (5) of the heating plate (2), characterized in that the heating device (1) has fixing arms (9) arranged on the edge (8) of the heating plate (2) for fixing the heating plate (2) on a carrier bracket (10) in the vacuum chamber (4), wherein each fixing arm (9) has at least one elastically displaceable spring element (11) and a fixing device (12) for fixing the corresponding spring element (11) on the corresponding carrier bracket (10).

2. The heating device (1) according to claim 1, characterized in that, the spring element (11) can be elastically displaced respectively on a displacement plane (13) extending parallel to the upper side (6) of the carrier layer (5).

3. The heating device (1) according to claim 1 or 2, characterized in that, the fixing arm (9) projects outward from the heating plate (2).

4. The heating device (1) according to any one of claims 1 to 3, characterized in that, the spring element (11) has a spring stiffness respectively in the range of 30 N / mm to 100 N / mm, preferably 50 N / mm to 80 N / mm.

5. The heating device (1) according to any one of claims 1 to 4, characterized in that, the heating element (7) is configured in a planar manner and is arranged in contact with the carrier layer (5) on the side of the carrier layer (5) opposite to the upper side (6).

6. The heating device (1) according to any one of claims 1 to 5, characterized in that, the heating element (7) is an electrically operated heating element (7), and the power supply line (14) of the heating device (1) is guided to the heating element (7) through at least one outwardly sealed pipe (15).

7. The heating device (1) according to any one of claims 1 to 6, characterized in that, the heating plate (2) has a notch (22) for allowing a lifting arm (16) to pass through, the lifting arm is used to lift a corresponding workpiece (3) from the upper surface (6) of the carrier layer (5) of the heating plate (2) or to hold a corresponding workpiece (3) above the upper surface (6) of the carrier layer (5) of the heating plate (2), and / or the heating device (1) has at least one temperature sensor (17) for measuring the temperature of the carrier layer (5) of the heating plate (2).

8. A vacuum chamber (4) having at least one heating device (1) according to any one of claims 1 to 7, wherein, The vacuum chamber (4) has a substrate (18) and preferably at least three carrier brackets (10) that project from the substrate (18) and are arranged at intervals from each other, and the heating plate (2) of the at least one heating device (1) is preferably fixed to the carrier bracket (10) only by means of the fixing device (12) of the fixing arm (9).

9. The vacuum chamber (4) according to claim 8, characterized in that the heating plates (2) of two or more heating devices (1) are arranged one above the other in the vacuum chamber (4).

10. The vacuum chamber (4) according to claim 8 or 9, characterized in that when heating by means of the at least one heating device (1), there is a temperature difference of at least 100 °C, preferably at least 200 °C, between the substrate (18) and the bearing layer (5) of the heating plate (2) of the at least one heating device (1).

Images