Heating plate and processing method thereof

Abstract

The invention provides a heating plate and a processing method of the heating plate. The processing method of the heating disc comprises the following steps: preparing an upper ceramic plate and a lower ceramic plate of the heating disc to be processed; performing first machining on the upper surface of the lower ceramic plate to enable the upper surface of the lower ceramic plate to reach first flatness required by a radio frequency electrode; a metal material is fixedly arranged on the upper surface of the lower ceramic plate to form a radio frequency electrode wire mesh; and adding ceramic powder around the radio frequency electrode screen mesh, covering the upper surface of the lower ceramic plate with the lower surface of the upper ceramic plate, and sintering the upper ceramic plate and the lower ceramic plate into a whole at high temperature to form the heating disc for improving the depth precision of the radio frequency electrode screen mesh, so that the capacitance consistency of a radio frequency field is improved, and the service life of the radio frequency field is prolonged. The uniformity of thin film deposition in the process is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing, and in particular to a heating plate and a processing method of the heating plate. Background Art

[0002] In the semiconductor manufacturing process, plasma enhanced chemical vapor deposition technology is widely used in the thin film deposition process. The plasma enhanced chemical vapor deposition process generates plasma in the radio frequency electric field to decompose the gas precursor and form a uniform film on the wafer surface. In this process, the ceramic heating plate, as one of the key components, not only carries the wafer, but also participates in the formation of the radio frequency circuit through its internal radio frequency electrode wire mesh, affecting the distribution of plasma and the uniformity of thin film deposition.

[0003] The RF electrode mesh in the ceramic heating plate is an important component of the RF circuit, and its depth change will directly affect the capacitance characteristics of the entire RF circuit. When the capacitance increases, the plasma intensity on the front of the wafer weakens, resulting in a decrease in the film deposition rate. Therefore, the non-uniformity of the depth of the RF electrode mesh will affect the capacitance consistency of the RF field, thereby affecting the distribution of the plasma and ultimately the uniformity of the film thickness. However, in the prior art, due to certain limitations in the processing technology of the ceramic disk, the difference between the maximum and minimum values ​​of the RF electrode mesh depth can usually only be controlled within 0.15 mm, which affects the capacitance consistency of the RF field.

[0004] In order to overcome the above-mentioned defects of the prior art, a heating plate technology is urgently needed in the art to improve the accuracy of the depth of the RF electrode screen, thereby improving the capacitance consistency of the RF field and improving the uniformity of thin film deposition in the process. Summary of the invention

[0005] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or decisive elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0006] In order to overcome the above-mentioned defects in the prior art, the present invention provides a heating plate and a processing method of a heating plate, which are used to improve the accuracy of the depth of the RF electrode screen, thereby improving the capacitance consistency of the RF field and improving the uniformity of thin film deposition in the process.

[0007] Specifically, the processing method of the heating plate provided by the first aspect of the present invention includes the following steps: preparing the upper ceramic plate and the lower ceramic plate of the heating plate to be processed; performing a first machining on the upper surface of the lower ceramic plate to make it reach the first flatness required for the radio frequency electrode; fixing a metal material on the upper surface of the lower ceramic plate to form a radio frequency electrode wire mesh; and adding ceramic powder around the radio frequency electrode wire mesh, covering the lower surface of the upper ceramic plate to the upper surface of the lower ceramic plate, and sintering the two at high temperature into one body to form the heating plate.

[0008] Further, in some embodiments of the present invention, the step of performing a first machining on the upper surface of the lower ceramic plate to make it reach the first flatness required for the radio frequency electrode includes: polishing the upper surface of the lower ceramic plate so that the height difference between the highest point and the lowest point on its upper surface is less than 0.01 mm.

[0009] Further, in some embodiments of the present invention, the step of fixing a metal material on the upper surface of the lower ceramic plate to form a radio frequency electrode wire mesh includes: heating the lower ceramic plate to a corresponding first temperature according to the characteristics of the metal material so that the metal material on the upper surface of the lower ceramic plate forms a flowing metal slurry; placing a mold with a hollow channel in the shape of a wire mesh on the upper surface of the lower ceramic plate, and filling the hollow channel of the mold with the metal slurry; curing the metal slurry; and removing the mold from the upper surface of the lower ceramic plate.

[0010] Further, in some embodiments of the present invention, the metal material of the radio frequency electrode wire mesh is molybdenum or tungsten, and the metal slurry includes the metal material, an organic solvent, and an adhesive.

[0011] Further, in some embodiments of the present invention, the step of sintering the two at high temperature into one body to form the heating plate includes: performing high-temperature sintering on the upper ceramic plate and the lower ceramic plate under the conditions that the process temperature is 1600 °C to 1900 °C, the process pressure is 10 Mpa to 30 Mpa, the process time is 120 hours to 168 hours, and the temperature change rate is ±2 °C / min to 4 °C / min.

[0012] Further, in some embodiments of the present invention, the step of preparing the lower ceramic plate includes: preparing a first ceramic plate at the lower part of the lower ceramic plate and a second ceramic plate at the upper part of the lower ceramic plate; machining a groove on the upper surface of the first ceramic plate and embedding a heating wire into the groove; and covering ceramic powder above the first ceramic plate, covering the lower surface of the second ceramic plate to the upper surface of the first ceramic plate, and sintering the two at high temperature into one body to form the lower ceramic plate.

[0013] Further, in some embodiments of the present invention, after covering the lower surface of the upper ceramic plate onto the upper surface of the lower ceramic plate and sintering the two together at high temperature, the processing method further includes the following steps: performing a second machining on the upper surface of the upper ceramic plate to make its second flatness meet the requirement of the difference in the embedding depth of the radio frequency electrode wire mesh.

[0014] Further, in some embodiments of the present invention, the step of performing a second machining on the upper surface of the upper ceramic plate to make its second flatness meet the requirement of the difference in the embedding depth of the radio frequency electrode wire mesh includes: polishing the upper surface of the upper ceramic plate so that the depth difference between the maximum depth and the minimum depth from the radio frequency electrode wire mesh to the upper surface of the upper ceramic plate is less than 0.1 mm.

[0015] Further, in some embodiments of the present invention, after covering the lower surface of the upper ceramic plate onto the upper surface of the lower ceramic plate and sintering the two together at high temperature to form the heating plate, the processing method further includes the following steps: welding a heating plate handle to the lower surface of the lower ceramic plate; passing a first metal rod through the heating plate handle to connect the radio frequency electrode wire mesh; passing a second metal rod through the heating plate handle to connect the heating wire; and machining a sealing ring on the upper surface of the upper ceramic plate to support the wafer to be heated.

[0016] In addition, the heating plate provided according to the second aspect of the present invention is formed by processing through the processing method of the heating plate described in any one of the first aspects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0018] Figure 1 Shows a schematic structural diagram of a heating plate provided according to some embodiments of the present invention.

[0019] Figure 2 Shows a schematic structural diagram of a radio frequency electrode wire mesh provided according to some embodiments of the present invention.

[0020] Figure 3 Shows a schematic flow diagram of a heating plate processing method provided according to some embodiments of the present invention.

[0021] Figure 4A Shows a schematic structural diagram of a heating wire embedded in a lower ceramic plate provided according to some embodiments of the present invention.

[0022] Figure 4B shows a schematic structural diagram of a radio frequency electrode wire mesh provided on the upper surface of a lower ceramic disc according to some embodiments of the present invention.

[0023] Figure 4C shows a schematic structural diagram of an upper ceramic plate and a lower ceramic plate sintered together at high temperature according to some embodiments of the present invention.

[0024] Figure 4D

[0024] shows a schematic structural diagram of a disc handle and a metal rod according to some embodiments of the present invention.

[0025] Figure 4E

[0025] shows a schematic structural diagram of a heating disc sealing ring according to some embodiments of the present invention.

[0026] Reference numerals:

[0027] 10 Upper ceramic plate

[0028] 20 Lower ceramic plate

[0029] 30 Radio frequency electrode wire mesh

[0030] 40 Heating wire

[0031] 50 Disc handle

[0032] 60 First metal rod

[0033] 70 Second metal rod

[0034] 80 Sealing ring Detailed implementation manners

[0035] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention will be introduced in conjunction with preferred embodiments, this does not mean that the features of this invention are limited to this implementation manner. On the contrary, the purpose of introducing the invention in conjunction with the implementation manner is to cover other alternatives or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, many specific details will be included in the following description. The present invention can also be implemented without using these details. In addition, in order to avoid confusing or obscuring the key points of the present invention, some specific details will be omitted in the description.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0038] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.

[0039] As mentioned above, in the semiconductor manufacturing process, plasma enhanced chemical vapor deposition technology is widely used in the thin film deposition process. The plasma enhanced chemical vapor deposition process generates plasma in the radio frequency electric field to decompose the gas precursor and form a uniform film on the surface of the wafer. In this process, the ceramic heating plate, as one of the key components, not only carries the wafer, but also participates in the formation of the radio frequency circuit through its internal radio frequency electrode wire mesh, affecting the distribution of plasma and the uniformity of thin film deposition.

[0040] The RF electrode mesh in the ceramic heating plate is an important part of the RF circuit. The change of its depth will directly affect the capacitance characteristics of the entire RF circuit. The following is the expression of the corresponding relationship between the depth of the RF electrode mesh and the capacitance: C = εS / d, Among them, d is the distance between the RF electrode wire mesh and the wafer, C is the capacitance, Z is the impedance between the wafer and the RF electrode wire mesh, ε is the dielectric constant, S is the area, and ω is the circular frequency.

[0041] It can be seen that when the capacitance increases, the plasma intensity on the front side of the wafer decreases, resulting in a decrease in the film deposition rate. Therefore, the non-uniformity of the RF electrode mesh depth will affect the capacitance consistency of the RF field, which in turn affects the distribution of the plasma and ultimately affects the uniformity of the film thickness.

[0042] However, in the prior art, due to certain limitations in the processing technology of the ceramic disc, the difference between the maximum and minimum values of the depth of the RF electrode wire mesh can usually only be controlled within 0.15 mm, thus affecting the capacitance consistency of the RF field.

[0043] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides a heating disc and a processing method of the heating disc, which are used to improve the accuracy of the depth of the RF electrode wire mesh, thereby enhancing the capacitance consistency of the RF field and improving the uniformity of thin film deposition in the process.

[0044] In some non-limiting embodiments, the heating disc provided in the second aspect of the present invention can be formed by processing through the processing method of the heating disc described in any one of the first aspects of the present invention.

[0045] For details, please refer to Figure 1 and Figure 2 , Figure 1 which shows a schematic structural diagram of a heating disc provided according to some embodiments of the present invention. Figure 2 which shows a schematic structural diagram of an RF electrode wire mesh provided according to some embodiments of the present invention.

[0046] As Figures 1 - 2 shown, the ceramic heating disc may include an upper ceramic plate 10, an RF electrode wire mesh 30, a lower ceramic plate 20, and a heating wire 40.

[0047] The following will describe the processing method of the ceramic heating disc in combination with the specific structure of the ceramic heating disc. Those skilled in the art can understand that these embodiments of the processing method of the ceramic heating disc are only some non-limiting implementation manners provided by the present invention, aiming to clearly show the main concept of the present invention and provide some specific solutions convenient for the public to implement, rather than limiting the execution subject or execution order of each step in the processing method of the ceramic heating disc.

[0048] Please refer to Figure 3 and Figures 4A - 4C , Figure 3 which shows a schematic flow chart of a processing method of a heating disc provided according to some embodiments of the present invention. Figure 4A which shows a schematic structural diagram of a heating wire embedded in a lower ceramic plate provided according to some embodiments of the present invention. Figure 4B which shows a schematic structural diagram of an RF electrode wire mesh provided on the upper surface of a lower ceramic disc according to some embodiments of the present invention. Figure 4C which shows a schematic structural diagram of an upper ceramic plate and a lower ceramic plate sintered together at high temperature according to some embodiments of the present invention.

[0049] As Figure 3 and Figures 4A - 4CAs shown, the processing method of the heating plate provided in the first aspect of the present invention may first perform step S1: Prepare the upper ceramic plate 10 and the lower ceramic plate 20 of the heating plate to be processed.

[0050] In some embodiments, the specific steps of the processing method of the heating plate for preparing the lower ceramic plate 20 may include: Prepare the first ceramic plate at the lower part of the lower ceramic plate 20 and the second ceramic plate at the upper part of the lower ceramic plate 20. After that, process a groove on the upper surface of the first ceramic plate, and embed the heating wire 40 into the groove. Then, cover ceramic powder on the first ceramic plate, cover the lower surface of the second ceramic plate onto the upper surface of the first ceramic plate, and sinter the two together at high temperature to form the lower ceramic plate 20.

[0051] Here, the process conditions for high-temperature sintering the lower ceramic plate 20 may be: Under the conditions that the process temperature is 1600°C to 1900°C, the process pressure is 10 Mpa to 30 Mpa, the process time is 120 hours to 168 hours, and the temperature change rate is ±2°C / min to 4°C / min, perform high-temperature sintering on the upper ceramic plate and the lower ceramic plate. Through this high-temperature and high-pressure sintering, the strength of the lower ceramic plate 20 for preventing the radio frequency electrode wire mesh 30 can be increased to the Gpa level, thereby effectively reducing the deformation amount of the radio frequency electrode wire mesh 30 placed thereon.

[0052] In some embodiments, the processing method of the heating plate may use the same ceramic material and prepare the upper ceramic plate 10 through the same high-temperature sintering process, which will not be elaborated here.

[0053] After that, the processing method of the heating plate may perform step S2: Perform first machining on the upper surface of the lower ceramic plate 20 to make it reach the first flatness required for the radio frequency electrode.

[0054] Specifically, the processing method of the heating plate may polish the upper surface of the lower ceramic plate 20 so that the height difference between the highest point and the lowest point on its upper surface is less than 0.01 mm.

[0055] In some embodiments, the processing method of the heating plate may also polish the lower surface of the upper ceramic plate 10 so that the height difference between the highest point and the lowest point on its upper surface is less than 0.01 mm.

[0056] Then, the processing method of the heating plate may perform step S3: Fix the metal material on the upper surface of the lower ceramic plate 20 to form the radio frequency electrode wire mesh 30. Here, the radio frequency electrode wire mesh 30 is used to provide radio frequency energy.

[0057] Specifically, the processing method of the heating plate can first heat the lower ceramic plate 20 to a corresponding first temperature (for example: 2600°C to 2650°C) according to the characteristics of the metal material, so that the metal material on the upper surface of the lower ceramic plate 20 forms a flowing metal slurry. Here, the solid metal material can be first placed on the upper surface of the lower ceramic plate 20 and then melted into a metal slurry on the lower ceramic plate 20, or the pre-heated metal slurry can be directly poured or coated onto the upper surface of the lower ceramic plate 20.

[0058] Then, place a mold with a hollow channel in the shape of a wire mesh on the upper surface of the lower ceramic plate of the lower disk, and fill the hollow channel of the mold with the metal slurry.

[0059] After that, cure the metal slurry and remove the mold from the upper surface of the lower ceramic plate of the lower disk, so as to fix the metal material on the upper surface of the lower ceramic plate 20 to form the radio frequency electrode wire mesh 30.

[0060] Here, the metal material of the radio frequency electrode wire mesh 30 can include molybdenum or tungsten, and the metal slurry includes the metal material, an organic solvent, and an adhesive.

[0061] After that, the processing method of the heating plate can perform step S4: Add ceramic powder (for example: aluminum nitride) around the radio frequency electrode wire mesh 30, cover the lower surface of the upper ceramic plate 10 onto the upper surface of the lower ceramic plate 20, and sinter the two together at a high temperature to form the heating plate.

[0062] Here, the processing method of the heating plate can perform high-temperature sintering on the upper ceramic plate 10 and the lower ceramic plate 20 under the conditions of a process temperature of 1600°C to 1900°C, a process pressure of 10 Mpa to 30 Mpa, a process time of 120 hours to 168 hours, and a temperature change rate of ±2°C / min to 4°C / min.

[0063] In this way, through the processing method of sintering the ceramic disk in two parts, namely the upper ceramic plate 10 and the lower ceramic plate 20, machining the surface of the lower ceramic plate 20 after sintering, printing the radio frequency electrode wire mesh 30 on a flat plane, and then sintering the upper and lower ceramic plates 20 together at a high temperature, the difference between the maximum value and the minimum value of the depth of the radio frequency electrode wire mesh 30 can be less than or equal to 0.1 mm, thereby improving the capacitance consistency of the radio frequency field and improving the uniformity of thin film deposition in the process.

[0064] In addition, in some embodiments, after covering the lower surface of the upper ceramic plate 10 onto the upper surface of the lower ceramic plate 20 and sintering the two together at a high temperature, the processing method further includes the following steps: Perform second machining on the upper surface of the upper ceramic plate 10 to make its second flatness meet the difference requirements of the embedding depth of the radio frequency electrode wire mesh 30.

[0065] Specifically, the upper surface of the upper ceramic plate 10 is polished so that the depth difference between the maximum depth and the minimum depth from the RF electrode wire mesh 30 to the upper surface of the upper ceramic plate 10 is less than 0.1 mm, thereby further improving the depth accuracy of the RF electrode wire mesh 30.

[0066] Please continue to refer to Figure 1 and Figures 4D - 4E . Figure 4D The structural schematic diagrams of the disc handle and the metal rod provided according to some embodiments of the present invention are shown. Figure 4E The structural schematic diagram of the heating disc sealing ring provided according to some embodiments of the present invention is shown.

[0067] As Figure 1 and Figure 4D shown, the ceramic heating disc may further include a disc handle 50, a first metal rod 60 and a second metal rod 70.

[0068] Specifically, after covering the lower surface of the upper ceramic plate 10 to the upper surface of the lower ceramic plate 20 and sintering the two together at high temperature, the processing method further includes the following steps: welding a heating disc handle 50 to the lower surface of the lower ceramic disc, and passing a first metal rod 60 through the heating disc handle 50 to connect the RF electrode wire mesh 30. Then, passing a second metal rod 70 through the heating disc handle 50 to connect the heating wire 40.

[0069] As Figure 1 and Figure 4E shown, the processing method may further machine a sealing ring 80 on the upper surface of the upper ceramic plate 10 to support the wafer to be heated.

[0070] In summary, the heating disc and its processing method provided by the present invention can be used to improve the accuracy of the depth of the RF electrode wire mesh, thereby improving the capacitance consistency of the RF field and enhancing the uniformity of thin film deposition in the process.

[0071] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions that are illustrated and described herein or not illustrated and described herein but are understood by those skilled in the art.

[0072] The foregoing description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A processing method of a heating plate, characterized in that The steps include: Prepare the upper ceramic plate and the lower ceramic plate of the heating plate to be processed; Perform first mechanical processing on the upper surface of the lower ceramic plate to make it reach the first flatness required for the RF electrode; Fix a metal material on the upper surface of the lower ceramic plate to form an RF electrode wire mesh; And Add ceramic powder around the RF electrode wire mesh, cover the lower surface of the upper ceramic plate onto the upper surface of the lower ceramic plate, and sinter the two together at high temperature to form the heating plate.

2. The processing method according to claim 1, wherein The step of performing first mechanical processing on the upper surface of the lower ceramic plate to make it reach the first flatness required for the RF electrode includes: Polish the upper surface of the lower ceramic plate so that the height difference between the highest point and the lowest point on its upper surface is less than 0.01 mm.

3. The processing method according to claim 1, characterized in that, The step of fixing a metal material on the upper surface of the lower ceramic plate to form an RF electrode wire mesh includes: According to the characteristics of the metal material, heat the lower ceramic plate to a corresponding first temperature to make the metal material on the upper surface of the lower ceramic plate form a flowing metal slurry; Place a mold with a wire mesh-shaped hollow channel on the upper surface of the lower ceramic plate, and fill the hollow channel of the mold with the metal slurry; Cure the metal slurry; and Remove the mold from the upper surface of the lower ceramic plate.

4. The processing method according to claim 3, characterized in that, The metal material of the RF electrode wire mesh is molybdenum or tungsten, and the metal slurry includes the metal material, an organic solvent, and an adhesive.

5. The processing method according to claim 1, wherein The step of sintering the two together at high temperature to form the heating plate includes: Under the conditions that the process temperature is 1600°C to 1900°C, the process pressure is 10 Mpa to 30 Mpa, the process time is 120 hours to 168 hours, and the temperature change rate is ±2°C / min to 4°C / min, perform high-temperature sintering on the upper ceramic plate and the lower ceramic plate.

6. The processing method according to claim 1, wherein The step of preparing the lower ceramic plate includes: Prepare the first ceramic plate at the lower part of the lower ceramic plate and the second ceramic plate at the upper part of the lower ceramic plate; Process a groove on the upper surface of the first ceramic plate and embed a heating wire into the groove; and Cover ceramic powder above the first ceramic plate, cover the lower surface of the second ceramic plate onto the upper surface of the first ceramic plate, and sinter the two together at high temperature to form the lower ceramic plate.

7. The processing method according to claim 1, characterized in that After covering the lower surface of the upper ceramic plate onto the upper surface of the lower ceramic plate and sintering the two together at high temperature, the processing method further includes the following steps: Perform second mechanical processing on the upper surface of the upper ceramic plate so that its second flatness meets the requirement of the difference in the embedding depth of the RF electrode wire mesh.

8. The processing method according to claim 7, characterized in that, The step of performing second mechanical processing on the upper surface of the upper ceramic plate so that its second flatness meets the requirement of the difference in the embedding depth of the RF electrode wire mesh includes: Polish the upper surface of the upper ceramic plate so that the depth difference between the maximum depth and the minimum depth from the RF electrode wire mesh to the upper surface of the upper ceramic plate is less than 0.1 mm.

9. The processing method according to claim 1, characterized in that, After covering the lower surface of the upper ceramic plate onto the upper surface of the lower ceramic plate and sintering the two at high temperature to form the heating plate, the processing method further includes the following steps: Welding a heating plate handle to the lower surface of the lower ceramic plate; Passing a first metal rod through the heating plate handle to connect the RF electrode wire mesh; Passing a second metal rod through the heating plate handle to connect the heating wire; and Processing a sealing ring on the upper surface of the upper ceramic plate to support the wafer to be heated.

10. A heating plate, characterized in that, The heating plate is formed by processing according to the processing method of the heating plate as described in any one of claims 1 to 9.

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