Etching ring and method for manufacturing etching ring

Abstract

For an etching ring provided with a first layer and a second layer, the second layer can be prevented from being exposed. An etching ring (1) for holding a wafer to be etched is provided with: a first layer (11) that includes a first region (111) and a second region (112) adjacent to the outer peripheral side of the first region (111) and holds an end portion of the wafer above the first region (111); and a second layer (12) laminated below the first layer (11), the first layer (11) being formed such that the layer thickness in the second region (112) does not expose the second layer due to loss during etching.

Description

Technical Field

[0001] The invention relates to an etching ring and a method for manufacturing the etching ring. Background Art

[0002] Plasma etching equipment for etching semiconductor wafers includes an etching ring for holding the wafer being etched (Patent Document 1). This etching ring is formed, for example, from CVD-SiC (Silicon Carbide) formed by CVD (Chemical Vapor Deposition).

[0003] To achieve a predetermined thickness, the etching ring is sometimes constructed from a multilayer SiC structure consisting of two or more layers stacked together. During etching, plasma loss is greatest in the area of ​​the etching ring adjacent to the outer periphery of the region holding the wafer end. This is because the plasma density is highest in this region.

[0004] In an etching ring composed of multiple layers of stacked SiC, if the first layer of the multilayer SiC is lost, exposing the second layer, there is a risk of some undesirable situation, such as impurities being released from the interface between the first and second layers. This is because, when the etching ring is constructed from multiple layers, for example, the period between the formation of the first layer and the formation of the second layer may be prolonged, making it more likely that impurities will be mixed into the interface.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-1947 Summary of the Invention

[0008] Technical problem to be solved by the invention

[0009] In conventional etching rings such as that disclosed in Patent Document 1, after forming a ring-shaped member composed of multiple layers of SiC, the thickness of the inner circumference of the first layer is reduced to form a region for holding the end portion of the wafer. As a result, the thickness of the first layer is thinner in the region adjacent to the outer circumference of the region for holding the end portion of the wafer than in other regions. Consequently, the second layer is more likely to be exposed due to the loss of the first layer during etching.

[0010] However, conventional etching rings have a problem in that they do not consider the technique of suppressing the loss of the first layer in the multilayer SiC and exposing the second layer.

[0011] The present disclosure is made to solve the above-mentioned technical problems, and an object thereof is to suppress exposure of the second layer in an etch ring including a first layer and a second layer.

[0012] Technical solutions to technical problems

[0013] An etching ring according to one embodiment of the present invention holds an etched wafer, wherein the ring comprises: a first layer comprising a first region and a second region adjacent to the outer periphery of the first region, and holding the end of the wafer above the first region; a second layer stacked below the first layer, wherein the first layer comprises a first region, a second region, a third region, and a fourth region in sequence from the inner periphery, wherein the first region is a region for holding the end of the wafer, the second region is a region located on the outer periphery of the first region and having the same thickness as that of the first region, the fourth region is a region located on the outermost periphery and having a thickness of the second layer thicker than that of the first layer, and a side surface portion of the third region is at a right angle or inclined between an upper surface portion of the second region and an upper surface portion of the fourth region.

[0014] Another embodiment of the present invention discloses a method for manufacturing an etching ring for holding an etched wafer, comprising the following steps: laminating a first layer and a second layer around a ring-shaped substrate; processing both end surfaces of the first and second layers in the lamination direction into flat surfaces; exposing the inner and outer peripheries of the substrate; removing the substrate; and processing the surface of the first layer on the side of the end portion holding the wafer. After forming one layer of the first and second layers around the substrate, the layers are stacked by forming another layer around the first layer. The first layer includes, from the inner periphery, a first region, a second region, a third region, and a fourth region. The second region is processed to be located on the outer periphery of the first region holding the end portion of the wafer and has the same thickness as the first region. The fourth region, located on the outermost periphery, is processed to have a thickness thicker than the first layer. The side surface of the third region is processed to be inclined between the upper surface portion of the second region and the upper surface portion of the fourth region.

[0015] Effects of the Invention

[0016] According to the etching ring of one embodiment of the present disclosure, the first layer is formed so that the thickness in the second region is such that the second layer is not exposed due to loss during etching. Therefore, in the etching ring including the first and second layers, exposure of the second layer can be suppressed.

[0017] According to another embodiment of the present invention, a method for manufacturing an etching ring is disclosed in which the first layer is processed in such a manner as to include a first region for holding an end portion of a wafer and a second region adjacent to an outer peripheral side of the first region, and the layer thickness in the second region is processed in such a manner as to prevent the second layer from being exposed due to loss during etching. Therefore, for an etching ring having a first layer and a second layer, exposure of the second layer can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a cross-sectional view of the etching ring 1 in the first embodiment.

[0019] Figure 2 This is a partial cross-sectional view of the etching ring 1 in the first embodiment.

[0020] Figure 3 This is a cross-sectional view illustrating the loss of the first layer 11 during etching of the etching ring 1 in the first embodiment.

[0021] Figure 4 This is a schematic diagram of the CVD film forming apparatus 4 for the etching ring 1 in the first embodiment.

[0022] Figure 5 This is a cross-sectional view of a substrate 5 for producing the etching ring 1 in the first embodiment.

[0023] Figure 6 This is a cross-sectional view of a laminate 6 in which a first layer 11 and a second layer 12 are laminated around a substrate 5 in the first embodiment.

[0024] Figure 7 1 is a cross-sectional view of the laminated body 6 showing a portion of the etched ring 1 obtained by processing the laminated body 6 according to the first embodiment using a processing device.

[0025] Figure 8 This is a flowchart showing the manufacturing process of the etching ring 1 according to the first embodiment.

[0026] Figure 9 This is a cross-sectional view of a substrate 5a for producing the etching ring 1 in the second embodiment.

[0027] Figure 10 This is a cross-sectional view of a laminate 6 a in which a first layer 11 and a second layer 12 are laminated around a base material 5 a in the first embodiment.

[0028] Figure 11 1 is a cross-sectional view of the laminated body 6 a showing a portion of the etched ring 1 obtained by processing the laminated body 6 a according to the second embodiment using a processing apparatus.

[0029] Figure 12 This is a flowchart showing the manufacturing process of the etching ring 1 according to the second embodiment.

[0030] Figure 13 This is a cross-sectional view of the entire etching ring 1a in the third embodiment.

[0031] Figure 14 FIG. 1 is a partial cross-sectional view of the etching ring 1 a in the third embodiment of the present invention, showing the etching ring 1 a in the first embodiment.

[0032] Figure 15 This is a cross-sectional view illustrating the loss of the first layer 11 a during etching of the etching ring 1 a in the third embodiment.

[0033] Figure 16 1 is a cross-sectional view of the laminated body 6 showing a portion of the etched ring 1 a obtained by processing the laminated body 6 according to the third embodiment using a processing device.

[0034] Figure 17 This is a flowchart showing the manufacturing process of the etching ring 1a according to the third embodiment.

[0035] Figure 18 1 is a cross-sectional view of the laminated body 6 showing a portion of the etched ring 1 a obtained by processing the laminated body 6 according to the third embodiment using a processing device.

[0036] Figure 19 1 is a flowchart showing a manufacturing process of the etching ring 1 a according to the fourth embodiment. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Hereinafter, multiple embodiments will be described, but it is assumed from the outset of the application that the structures described in each embodiment will be appropriately combined. It should be noted that identical or corresponding parts in the figures are marked with the same reference numerals, and their descriptions will not be repeated.

[0038] [Implementation Method 1]

[0039] (Overall structure of etching ring 1)

[0040] Figure 1 : is a cross-sectional view of the entire etching ring 1 in embodiment 1. Figure 1 In FIG, a cross section along the center line of the annular etching ring 1 is shown.

[0041] Etching ring 1 is installed inside a plasma etching device (not shown). Etching ring 1 is a ring-shaped component formed by laminating a first layer 11 and a second layer 12. First layer 11 is made of SiC (Silicon Carbide). Second layer 12 is also made of SiC. In etching ring 1, second layer 12 is laminated below first layer 11. Because etching ring 1 is annular, a circular space 13 is formed on the inner circumference.

[0042] In the etching ring 1, a holding portion 14 is provided on the inner circumference of the upper surface of the first layer 11 to hold the wafer 2 to be etched. The wafer 2 is disc-shaped. The holding portion 14 is a portion with a step-like thickness that is one step smaller than the rest of the etching ring 1.

[0043] Wafer 2 is secured by a chuck device provided in the plasma etching apparatus. Thus, the end of wafer 2 is held within the space of holding portion 14 of etching ring 1. In this example, the end of wafer 2 is held within the space of holding portion 14 in a non-contact state with respect to etching ring 1. It should be noted that wafer 2 can also be placed on holding portion 14 with its end in contact with the holding portion 14 of etching ring 1.

[0044] (Detailed structure of etching ring 1)

[0045] Figure 2 This is a partial cross-sectional view of the etching ring 1 in the first embodiment. Figure 2 In, enlarged Figure 1 The cross section of the etched ring 1 is shown on the right.

[0046] The first layer 11 of the etching ring 1 includes a first region 111, a second region 112, a third region 113, and a fourth region 114. The upper surface of the first region 111, the upper surface of the second region 112, and the side surface of the third region 113 constitute a holding portion 14.

[0047] First region 111 is a region including the inner circumferential end of etching ring 1. Second region 112 is a region adjacent to the outer circumference of first region 111. Third region 113 is a region adjacent to the outer circumference of second region 112. Fourth region 114 is a region adjacent to the outer circumference of third region 113. Fourth region 114 includes the inner circumferential end of etching ring 1.

[0048] First region 111 is an area that holds the end of wafer 2 above. Second region 112 is an area that does not hold the end of wafer 2 above. Third region 113 is a region that projects upward from first region 111 and second region 112, so that when the end of wafer 2 is placed above first region 111, it faces the end of wafer 2. With this shape, third region 113 surrounds the entire circumference of the end of wafer 2 from the outer periphery when the end of wafer 2 is placed above first region 111.

[0049] The upper surface portion of the first region 111 and the upper surface portion of the second region 112 are located at the same height. The upper surface portion of the first region 111 and the upper surface portion of the second region 112 are located one level lower than the upper surface portion of the fourth region 114. The side portion of the third region 113 is a region connecting the upper surface portion of the second region 112 and the upper surface portion of the fourth region 114. The side portion of the third region 113 is inclined between the upper surface portion of the second region 112 and the upper surface portion of the fourth region 114. It should be noted that the side portion of the third region 113 is not limited to the upper surface portion of the second region 112 and the upper surface portion of the fourth region 114. Figure 2 You can tilt it like that, or you can not tilt it.

[0050] In first layer 11, the surface formed by the upper surface of first region 111, the upper surface of second region 112, the side surface of third region 113, and the upper surface of fourth region 114 is referred to as first surface 91. In first layer 11, the surface opposite first surface 91 is referred to as second surface 92.

[0051] The second layer 12 is formed below the second surface 92. The second layer 12 includes a first region 121, a second region 122, and a third region 123. The first region 121 of the second layer 12 corresponds to the first region 111 and the second region 112 of the first layer 11. The second region 122 of the second layer 12 corresponds to the third region 113 of the first layer 11. The third region 123 of the second layer 12 corresponds to the fourth region 114 of the first layer 11.

[0052] In the second layer 12, a first region 121 of the second layer 12 is located opposite the first region 111 and the second region 112 of the first layer 11. In the second layer 12, a second region 122 of the second layer 12 is located opposite the third region 113 of the first layer 11. In the second layer 12, a third region 123 of the second layer 12 is located opposite the fourth region 114 of the first layer 11.

[0053] In second layer 12, the surface formed by the upper surface of first region 121, the side surface of second region 122, and the upper surface of third region 123 is called third surface 93. In second layer 12, the surface facing third surface 93 is called fourth surface 94.

[0054] The first layer 11 is formed so that the thickness in the second region 112 is thicker than the thickness in the first region 121 of the second layer 12. This structure is to prevent the second layer 12 from being exposed due to loss of the first layer 11 during etching.

[0055] Thus, in the etching ring 1, the thickness of the first layer 11 in the second region 112 is formed thicker than the thickness of the second layer 12 in the first region 121. Figure 2 As shown, the position of the interface 15 between the first layer 11 and the second layer 12 from the bottom surface of the second layer 12 is located in the first region 121 of the second layer 12 lower than the positions of the second region 122 and the third region 123 of the second layer 12.

[0056] (Structure for Preventing Exposure of Second Layer 12 Due to Loss of First Layer 11 During Etching)

[0057] Figure 3 This is a cross-sectional view illustrating the loss of the first layer 11 during etching of the etching ring 1 in the first embodiment.

[0058] When plasma etching is performed in the etching apparatus, the plasma-induced loss is greatest in the second region 112 of the first layer 11 in the etching ring 1. This is because the plasma density is highest in the second region 112, which is adjacent to the outer periphery of the first region 111 above which the end of the wafer 2 is located, in the first layer 11.

[0059] When the wafer 2 is subjected to plasma etching, as shown in FIG. Figure 3 As shown, in the second region 112, the first layer 11 is lost, creating a hole 3, and the thickness of the second region 112 is reduced. To prevent the second layer 12 from being exposed due to this etching loss, the first layer 11 is formed so that the thickness in the second region 112 is a thickness that does not allow the second layer 12 to be exposed due to etching loss. Specifically, the thickness of the first layer 11 in the second region 112 is set to be as large a proportion as possible of the total thickness of the first layer 11 and the second layer 12 below the retaining portion 14 of the etching ring 1.

[0060] Thus, in the etching ring 1 of embodiment 1, the thickness of the first layer 11 in the second region 112 is formed to a thickness at which the second layer 12 is not exposed due to loss during etching. Thus, for the etching ring 1 having the first layer 11 and the second layer 12, exposure of the second layer 12 during etching can be suppressed.

[0061] (Etching Ring 1 Manufacturing Apparatus)

[0062] Figure 4 This is a schematic diagram of the CVD film forming apparatus 4 included in the manufacturing apparatus for the etching ring 1 in the first embodiment.

[0063] The CVD film forming apparatus 4 includes a chamber 41 , a high-frequency power supply 42 , a vacuum pump 43 , a raw material gas container 44 , a first valve 451 , a second valve 452 , and a control device 49 .

[0064] The control device 49 includes a CPU (Central Processing Unit) 491, memories (ROM (Read Only Memory) and RAM (Random Access Memory) 492), an input / output buffer (not shown), and the like. The CPU 491 expands the program stored in the ROM into the RAM and executes it. The program stored in the ROM describes the processing sequence of the control executed by the control device 49. The control device 49 controls the various devices in the CVD film forming apparatus 4 according to this program.

[0065] The control device 49 controls various devices in the chamber 41 , including the high-frequency power supply 42 , the vacuum pump 43 , the first valve 451 , and the second valve 452 .

[0066] A film forming stage 46, a heater 47, and a shower head 48 are provided within the chamber 41. The heater 47 is provided within the shower head 48. A substrate 5 of the etching ring 1, the target of film formation, is held above the film forming stage 46. The substrate 5 is made of, for example, graphite. The substrate 5 is held so that film formation is performed over the entire circumference. It should be noted that the substrate 5 may also be made of materials other than graphite.

[0067] The first valve 451 is provided in the gas path between the vacuum pump 43 and the chamber 41 . The second valve 452 is provided in the gas path between the source gas container 44 and the chamber 41 .

[0068] When forming a film on the substrate 5 in the CVD film forming apparatus 4, the control device 49 closes the second valve 452, opens the first valve 451, and controls the operation of the vacuum pump 43. As a result, the interior of the chamber 41 is in a vacuum state.

[0069] Afterwards, the control device 49 controls the second valve 452 to open while closing the first valve 451 and maintaining a vacuum inside the chamber 41. This allows the raw material gas to be supplied from the raw material gas container 44 into the chamber 41. While the raw material gas is being supplied into the chamber 41, the control device 49 controls the high-frequency power supply 42 to supply high-frequency power to the electrodes of the showerhead 48. As a result, the raw material gas is converted into plasma within the chamber 41 and discharged from the showerhead 48.

[0070] When forming a film on substrate 5 in CVD film forming apparatus 4, control unit 49 supplies power to heater 47 to control heating of the heater. This heats the film forming object such as substrate 5 while forming a film of the substance contained in the source gas on the film forming object.

[0071] In such a CVD film forming apparatus 4, SiC film is formed around the substrate 5, thereby performing the process for manufacturing the SiC film. Figures 1 to 3 The film formation of the etching ring 1 is shown.

[0072] The manufacturing apparatus for the etching ring 1 includes, in addition to the CVD film forming apparatus 4 , a processing apparatus (not shown) for performing processing such as cutting on the etching ring 1 .

[0073] (Method for Manufacturing Etched Ring 1)

[0074] In the following description Figures 5 to 7 An example of manufacturing two etching rings 1 at the same time is shown in FIG. Figures 5 to 7In order to clarify the manufacturing range of one etching ring 1 , the boundary between the manufacturing ranges of two etching rings 1 is indicated by a dashed line 70 .

[0075] Figure 5 This is a cross-sectional view of a substrate 5 used to manufacture the etching ring 1 in Embodiment 1. The substrate 5 is an annular member in which a first region 51 on the outer circumference is thinner than a second region 52 on the inner circumference. Since the substrate 5 is annular, a circular space 53 is formed on the inner circumference.

[0076] The first region 51 and the second region 52 of the substrate 5 are formed so that the interface between the stacked first layer and the second layer becomes Figure 2 The shape is determined in the form of a cross-sectional shape such as the interface 15 shown.

[0077] Figure 6 This is a cross-sectional view of a laminate 6 in which a first layer 61 and a second layer 62 are laminated around a base material 5 in the first embodiment.

[0078] In the formation Figure 6 In the case of the laminated body 6 shown, first, a first layer 61 is formed around the substrate 5 in the CVD film forming apparatus 4. The first layer 61 is a layer that becomes the first layer 11 of the etching ring 1. The first layer 61 is a SiC layer.

[0079] Next, in the CVD film forming apparatus 4, a second layer 62 is formed around the first layer 61. The second layer 62 serves as the second layer 12 of the etching ring 1. The second layer 62 is a SiC layer. Since the substrate 5 of the stacked body 6 is annular, a circular space 63 is formed on the inner circumference after the first layer 61 and the second layer 62 are stacked.

[0080] After forming the first layer 61, the laminate 6 is usually Figure 4 The laminate 6 with the first layer 61 formed thereon is then placed back into the chamber 41. The second layer 62 is then formed around the first layer 61 in the laminate 6. It should be noted that the laminate 6 with the first layer 61 formed thereon may also be stored inside the chamber 41.

[0081] like Figure 6 As shown, the shape of the substrate 5 is such that the thickness of the first region 51 on the outer circumference side is thinner than the thickness of the second region 52 on the inner circumference side. Accordingly, the shape of the first layer 61 of the laminate 6 is such that the thickness of the outer circumference side region is thinner than the thickness of the inner circumference side region, similarly to the shape of the substrate 5. Due to this shape of the first layer 61, the shape of the second layer 62 is such that the thickness of the outer circumference side region is thinner than the thickness of the inner circumference side region, similarly to the shape of the substrate 5.

[0082] In the CVD film forming apparatus 4, Figure 6 After the laminated body 6 is processed in a processing device, the laminated body 6 can be obtained. Figures 1 to 3 Etched ring 1 of the shape shown.

[0083] Figure 7 1 is a cross-sectional view of a laminated body 6 showing a portion of an etched ring 1 obtained by processing the laminated body 6 of the first embodiment using a processing device. Figure 7 As shown, in the stack 6 , two etching rings 1 can be obtained.

[0084] The following, to obtain Figure 7 The etching ring 1 shown in the lower part of the figure is a representative example of the two etching rings 1 shown in the figure, and the processing part for obtaining the etching ring 1 is explained. In the processing device, the laminated body 6 is processed as shown below to obtain Figure 2 Etched ring 1 with the structure shown.

[0085] In the case of obtaining the etched ring 1 shown at the bottom of the figure in the stacked body 6, the processing apparatus first performs a process of planarizing the lower surface of the stacked body 6 by cutting to a position indicated by, for example, a dotted line 71, and a process of planarizing the upper surface of the stacked body 6 by cutting to a position indicated by, for example, a dotted line 72. Thus, both end surfaces of the stacked body 6 in the stacking direction are planarized.

[0086] Next, in the processing device, the outer peripheral side of the stack 6 is cut to a position such as the dotted line 73 to expose the first area 51 of the substrate 5, and the inner peripheral side of the stack 6 is cut to a position such as the dotted line 74 to expose the second area 52 of the substrate 5.

[0087] In the process of exposing the first region 51 of the substrate 5, the outer circumference of the laminate 6 is cut to the same position as the predetermined outer circumference of the etching ring 1 indicated by the dotted line 73, using the center position of the circle of the substrate 5 as the reference position. In the process of exposing the second region 52 of the substrate 5, the inner circumference of the laminate 6 is cut to the same position as the predetermined inner circumference of the etching ring 1 indicated by the dotted line 74, using the center position of the circle of the annular substrate 5 as the reference position.

[0088] It should be noted that, in the process of exposing the first region 51 of the substrate 5, it is sufficient to cut the laminate 6 until at least the end portion on the outer peripheral side and the end portion on the inner peripheral side of the substrate 5 are exposed. Figure 7 The dotted line 73 shows the position of the cutting and Figure 7 Cutting at the position indicated by the dotted line 74 may also be performed after the substrate 5 is removed.

[0089] Next, a process of removing the base material 5 by chemical treatment is performed. Thus, in the laminate 6, the Figure 7 The first part of the etching ring 1 shown on the upper side of the single dot chain line 70 is used to make Figure 7 The second part of the etching ring 1 shown on the lower side of the single-dot chain line 70 is separated.

[0090] The following is for making Figure 7 The components of the etching ring 1 are shown on the lower side of FIG. 1 , and a processing method for manufacturing the etching ring 1 is described.

[0091] Will be used to make Figure 7 The second part of the etching ring 1 shown on the lower side is held in the processing part of the processing device in such a manner that the second layer 62 side of the planarization as described above faces downward. Then, in the processing device, the upper surface side of the etching ring 1 is cut so that the thickness distribution of the first layer 11 in the radial direction of the etching ring 1 becomes Figure 2 The thickness distribution is shown.

[0092] Specifically, the upper surface of the second component is cut with the lower end of the substrate 5 as the reference position so that the interface 15 between the first layer 11 and the second layer 12 in the etched ring 1 becomes Figure 2 For example, the second part is cut to Figure 7 The second part is cut to the position as shown in the dotted line 75, or the second part is cut to the position as shown in the dotted line 75 Figure 7 In this case, each position where the upper surface side of the second component is cut is estimated in advance based on the elapsed time from the start to the end of film formation of the first layer 11 and the second layer 12 and the film formation speed of the first layer 11 and the second layer 12.

[0093] in addition, Figure 7 The third region 113 of the first layer 11 in the illustrated etched ring 1 is formed by cutting the second member from the center position of the circle of the substrate 5 as a reference position to a predetermined position.

[0094] In addition, in the processing device, the lower end position of the base material 5 is used as a reference position, and the lower surface side of the second member is cut so that the lower surface side of the second member becomes Figure 2 For example, Figure 7 As shown by the dotted line 77, Figure 2 Below the first region 111, the second region 112, and the entire third region 113 of the first layer 11 and a portion of the fourth region 114a, the second component is cut until the thickness of the second layer 62 becomes Figure 2In this case, the position where the lower surface side of the second member is cut is estimated in advance based on the elapsed time from the start to the end of the formation of the first layer 11 and the second layer 12 and the formation speed of the first layer 11 and the second layer 12.

[0095] As a result, the first region 111, the second region 112, and the entire third region 113 of the first layer 11 in the etching ring 1 and a portion of the fourth region 114a are formed below. Figure 2 The structure of the second layer 12 is shown to have a thickness.

[0096] The first component can be obtained by performing the same processing as the second component. Figure 2 Etched ring 1 with the structure shown.

[0097] In the first embodiment, as described above, the CVD film forming apparatus 4 is used to form the Figure 6 Then, the laminate 6 is processed by a processing device such as Figure 7 By processing the laminate 6 in this way, it is possible to obtain Figures 1 to 3 Etched ring 1 of the construction shown.

[0098] (Manufacturing process of etching ring 1)

[0099] Figure 8 This is a flowchart showing the manufacturing process of the etching ring 1 according to the first embodiment. Figure 8 For the purpose of realizing the above Figures 5 to 7 The flow of the manufacturing process of the manufacturing method of the etching ring 1 described in the above will be summarized and described.

[0100] about Figure 8 The manufacturing process shown summarizes the manufacturing method of the etching ring 1 described above, and is mainly described to clarify the flow of the manufacturing process.

[0101] In the process of step S1, the first layer 61 of SiC is formed around the substrate 5 in the CVD film forming apparatus 4. Specifically, in the process of step S1, as described above, the first layer 61 of SiC is formed around the substrate 5. Figure 6 The first layer 61 is formed in the manner of the cross-sectional shape shown.

[0102] In the process of step S2, in the CVD film forming apparatus 4, the second layer 62 composed of SiC is formed around the first layer 61. In the process of step S2, specifically, as described above, around the first layer 61, Figure 6 The second layer 12 is formed in the manner of the cross-sectional shape shown in FIG. By performing the process of step S1 and the process of step S2, the Figure 6 The laminated body 6 shown.

[0103] In step S3, the upper surface of the laminate 6 is flattened in a processing device, and the lower surface of the laminate 6 is flattened. In step S3, as described above, the upper and lower surfaces of the laminate 6 are flattened.

[0104] In step S4, the inner and outer circumferences of the substrate 5 are exposed in the processing apparatus. Specifically, in step S4, as described above, the inner circumference of the laminate 6 is cut to a predetermined first position with the center position of the circle of the substrate 5 as the reference position. Furthermore, in step S4, as described above, the outer circumference of the laminate 6 is cut to a predetermined second position with the center position of the circle of the substrate 5 as the reference position, thereby exposing the outer circumference of the substrate 5.

[0105] In step S5, the base material 5 is removed in a processing device. Specifically, in step S5, the base material 5 exposed in step S4 is removed by chemical treatment. In this way, the first member and the second member described above are obtained.

[0106] In the process of step S6, in the processing device, a cutting process is performed on the portion of the first component or the second component that becomes the upper surface side of the etching ring 1 to form the first layer 11 and the second layer 12. Figure 2 The thickness of the first layer 11 in the second region 112 is shown to be Figure 2 The second layer 12 is shown to have a thickness that is not exposed due to loss during etching.

[0107] Specifically, in step S6 , as described above, the lower end position of the substrate 5 is used as a reference position, and a portion to be the upper surface of the etching ring 1 is cut by a predetermined thickness, thereby processing the surface on the first layer 11 side.

[0108] In the process of step S6, the processing device performs the cutting process of the first component or the second component with the lower end position of the substrate 5 as the reference position so that the portion of the first component or the second component that becomes the lower surface side of the etching ring 1 becomes Figure 2 Thus, in the process of step S6 , the second layer 12 is processed so that the second layer 12 exists below the second region 112 in the first layer 11 .

[0109] By executing the manufacturing process as described above, it is possible to obtain Figure 1 and Figure 2 Etched ring 1 with the structure shown.

[0110] It should be noted that, regarding the etching ring 1 of embodiment 1, an example is shown in which the first layer 11 and the second layer 12 are composed of the same SiC. However, this is not limiting, and the first layer 11 and the second layer 12 may be composed of different materials. For example, the second layer 12 may also be composed of a silicon raw material other than SiC. In addition, the etching ring 1 is not limited to a structure in which two layers of SiC are stacked, but may also be stacked with three or more layers of SiC. For example, regarding the etching ring 1, in order to increase the thickness of the etching ring 1, it is sometimes composed of a structure in which three or more layers of multilayer SiC are stacked. In the case of stacking three or more layers of multilayer SiC, the third layer or more is, for example, Figures 1 to 3 In the etching ring having a structure of multilayer SiC stacked with three or more layers, the third and subsequent SiC layers are layers whose interfaces are not exposed as in the case of the second layer 12 even if the first layer 11 is lost as described above. Thus, the technology related to the etching ring 1 of this embodiment can also be applied to etching rings having a structure of multilayer SiC stacked with three or more layers.

[0111] Furthermore, in the etching ring 1 of the first embodiment, an example is shown in which the first region 111 of the first layer 11 is formed so that the thickness of the first layer 11 is such that the second layer 12 is not exposed due to loss during etching, in addition to the second region 112 of the first layer 11. However, this is not limiting, and the region of the first layer 11 having a thickness such that the second layer 12 is not exposed due to loss during etching only needs to be at least the second region 112 of the first layer 11.

[0112] In the etching ring 1 of the first embodiment described above, the following technical effects can be obtained.

[0113] (1) In the etching ring 1 of embodiment 1, as Figure 2 and Figure 3 As shown, when etching is performed, in the second region 112, which is the region where the first layer 11 is lost in the thickness direction, the thickness of the first layer 11 is formed to a thickness that prevents the second layer 12 from being exposed due to loss during etching. Thus, in the etching ring 1 including the first layer 11 and the second layer 12, the thickness of the first layer 11 can suppress exposure of the second layer 12.

[0114] (2) In the etching ring 1 of embodiment 1, as Figures 1 to 3 As shown, the first layer 11 is formed thicker than the second layer 12 in the thickness direction of the second region 112. Therefore, in the etching ring 1 including the first layer 11 and the second layer 12, the first layer 11 is thicker than the second layer 12, thereby preventing the second layer 12 from being exposed during etching.

[0115] (3) In the etching ring 1 of embodiment 1, as Figure 2 and Figure 3As shown, the second layer 12 is stacked below the first layer 11 so that the second layer 12 exists below the second region 112 of the first layer 11. Thus, in the etching ring 1 including the first layer 11 and the second layer 12, the second layer 12 existing below the first layer 11 can be prevented from being exposed during etching due to the thickness of the first layer 11.

[0116] (4) In the etching ring 1 of Embodiment 1, the first layer 11 and the second layer 12 are made of SiC. Therefore, in the etching ring 1 in which the first layer 11 and the second layer 12 are made of SiC, exposure of the second layer 12 during etching can be suppressed.

[0117] (5) In the etching ring 1 of embodiment 1, as Figure 3 As shown, the first layer 11 in the second region 112 is a region that is lost in the thickness direction of the second region 112 when the chip 2 whose end is held above the first region 111 is etched. Thus, in the etching ring 1, in the region lost during etching, exposure of the second layer 12 during etching can be suppressed.

[0118] (6) In the etching ring 1 of embodiment 1, as Figure 2 and Figure 3 As shown, the first layer 11 further includes a third region 113 adjacent to the outer periphery of the second region 112. The third region 113 has a protruding shape and faces the end of the wafer 2 when the end of the wafer 2 is held above the first region 111. Thus, in the etching ring 1, when the wafer 2 is held, the outer periphery of the wafer 2 can be surrounded by the third region 113.

[0119] (7) In the method for manufacturing the etching ring 1 of embodiment 1, as Figures 5 to 8 As shown, the first layer 11 is processed to include a first region 111 that holds the end of the wafer 2 and a second region 112 adjacent to the outer periphery of the first region 111. The thickness of the first layer 11 in the second region 112 is processed to a thickness that prevents the second layer 12 from being exposed due to loss during etching. Thus, in the etching ring 1 having the first layer 11 and the second layer 12, exposure of the second layer 12 can be suppressed.

[0120] (8) In the method for manufacturing the etching ring 1 of embodiment 1, as Figures 5 to 8 As shown, the first layer 11 is processed to be thicker than the second layer 12 in the thickness direction of the second region 112. Thus, in the etching ring 1 including the first layer 11 and the second layer 12, the first layer 11 is thicker than the second layer 12, thereby preventing the second layer 12 from being exposed during etching.

[0121] (9) In the etching ring 1 of embodiment 1, as Figures 5 to 8As shown, the second layer 12 is processed so that the second layer 12 exists below the second region 112 of the first layer 11. Thus, in the etching ring 1 including the first layer 11 and the second layer 12, the second layer 12 existing below the first layer 11 can be prevented from being exposed during etching due to the thickness of the first layer 11.

[0122] [Implementation Method 2]

[0123] Next, use Figures 9 to 12 The second embodiment is described. In the second embodiment, Figures 1 to 3 Another method of manufacturing the etching ring 1 shown will be described.

[0124] The difference between the second embodiment and the first embodiment is mainly in the following aspects. In the second embodiment, a substrate 5a having a shape different from that of the substrate 5 of the first embodiment is used (see Figure 9 In the second embodiment, a stacked body 6a (see FIG. 1 ) in which the first layer 61 and the second layer 62 are stacked is formed in a different order from that of the stacked body 6 in the first embodiment. Figures 10 to 12 In the second embodiment, the stacked body 6a is cut in a different order from the stacked body 6 in the first embodiment (see Figure 11 、 Figure 12 wait).

[0125] (Method for Manufacturing Etched Ring 1)

[0126] In the following description Figures 9 to 11 FIG shows an example of manufacturing two etching rings 1 simultaneously in Embodiment 2. Figures 9 to 11 In order to clarify the manufacturing range of one etching ring 1 , the boundary between the manufacturing ranges of two etching rings 1 is indicated by a dashed line 70 .

[0127] Figure 9 This is a cross-sectional view of a substrate 5a used to manufacture the etching ring 1 in Embodiment 2. The substrate 5a is an annular member in which the thickness of a first region 51a on the inner circumference is thinner than the thickness of a second region 52a on the outer circumference. Because the substrate 5a is annular, a circular space 53a is formed on the inner circumference.

[0128] The first region 51a and the second region 52a of the substrate 5a are formed so that the interface between the stacked first layer 61 and the second layer 62 becomes Figure 2 The shape is determined in the form of a cross-sectional shape such as the interface 15 shown.

[0129] Figure 10 This is a cross-sectional view of a laminate 6a in which a first layer 61 and a second layer 62 are laminated around a base material 5a in the first embodiment.

[0130] In the formation Figure 10 In the case of the laminated body 6a shown, first, the second layer 62 is formed around the substrate 5a in the CVD film forming apparatus 4. The second layer 62 is a layer that becomes the second layer 12 of the etching ring 1. The second layer 62 is a SiC layer.

[0131] Next, in the CVD film forming apparatus 4, the first layer 61 is formed around the second layer 62. The first layer 61 is the layer that becomes the first layer 11 of the etching ring 1. The first layer 61 is a SiC layer. Since the substrate 5a of the stacked body 6a is annular, a circular space 63a is formed on the inner circumference after the first layer 61 and the second layer 62 are stacked.

[0132] After forming the second layer 62, the laminate 6a is usually Figure 4 The laminate 6a is stored outside the chamber 41 for a predetermined period. The laminate 6a, with the second layer 62 formed thereon, is then placed back into the chamber 41. In this laminate 6a, the first layer 61 is formed around the second layer 62. It should be noted that the laminate 6a, with the second layer 62 formed thereon, can also be stored inside the chamber 41.

[0133] like Figure 10 As shown, the shape of the substrate 5a is such that the thickness of the first region 51a on the inner circumference is thinner than the thickness of the second region 52a on the outer circumference. Accordingly, the shape of the second layer 62 of the laminate 6a is such that the thickness of the inner circumference region is thinner than the thickness of the outer circumference region, similarly to the shape of the substrate 5a. Due to this shape of the second layer 62, the shape of the first layer 61 is such that the thickness of the inner circumference region is thinner than the thickness of the outer circumference region, similarly to the shape of the substrate 5a.

[0134] In the formation Figure 10 After the laminated body 6a shown in FIG. 1 is processed in a processing device, the laminated body 6a can be obtained. Figures 1 to 3 Etched ring 1 of the shape shown.

[0135] Figure 11 1 is a cross-sectional view of a laminated body 6a showing a portion of an etched ring 1 obtained by processing the laminated body 6a of the second embodiment using a processing device. Figure 11 As shown, in the stacked body 6a, two etching rings 1 can be obtained.

[0136] The following, to obtain Figure 11 The etching ring 1 shown in the lower part of the figure is a representative example, and the processing part for obtaining the etching ring 1 is explained. In the processing device, the stacked body 6a is processed as shown below to obtain Figure 2 Etched ring 1 with the structure shown.

[0137] In order to obtain the etched ring 1 shown at the bottom of the figure in the laminate 6a, the processing apparatus first performs a process of planarizing the lower surface of the laminate 6a by cutting to a position indicated by, for example, a dotted line 71a, and a process of planarizing the upper surface of the laminate 6a by cutting to a position indicated by, for example, a dotted line 72a. Thus, both end surfaces of the laminate 6a in the stacking direction are planarized.

[0138] Next, in the processing device, the outer peripheral side of the stack 6a is cut to a position such as the dotted line 73a to expose the second area 52a of the substrate 5a, and the inner peripheral side of the stack 6a is cut to a position such as the dotted line 74a to expose the first area 51a of the substrate 5a.

[0139] In the process of exposing the second region 52a of the substrate 5a, the outer circumference of the laminate 6a is cut to the same position as the predetermined outer circumference of the etching ring 1 indicated by the dotted line 73a, using the center position of the circle of the substrate 5a as the reference position. In the process of exposing the first region 51a of the substrate 5a, the inner circumference of the laminate 6a is cut to the same position as the predetermined inner circumference of the etching ring 1 indicated by the dotted line 74a, using the center position of the circle of the substrate 5a as the reference position.

[0140] It should be noted that in the process of exposing the first area 51a of the substrate 5a, it is sufficient to cut the stack 6a until at least the end portion on the outer peripheral side and the end portion on the inner peripheral side of the substrate 5a are exposed. Cutting to the position indicated by the dotted line 73a and cutting to the position indicated by the dotted line 74a can be performed after removing the substrate 5a.

[0141] Next, the substrate 5a is removed by chemical treatment. Figure 11 The first part of the etching ring 1 shown on the upper side of the single dot chain line 70 is used to make Figure 11 The second part of the etching ring 1 shown on the lower side of the single-dot chain line 70 is separated.

[0142] The following is for making Figure 11 The components of the etching ring 1 are shown on the lower side of FIG. 1 , and a processing method for manufacturing the etching ring 1 is described.

[0143] Will be used to make Figure 11 The second part of the etching ring 1 shown on the lower side is held in the processing part of the processing device in such a manner that the first layer 61 side flattened as described above faces the vertical direction. Then, in the processing device, the upper surface side of the etching ring 1 is cut so that the thickness distribution of the first layer 11 in the radial direction of the etching ring 1 becomes Figure 2 The thickness distribution is shown.

[0144] Specifically, the lower surface of the second member is cut with the lower end of the substrate 5a as the reference position so that the interface 15 between the first layer 11 and the second layer 12 in the etched ring 1 becomes Figure 2 For example, the second part is cut to Figure 11 The second part is cut to the position as shown in the dotted line 75a, or the second part is cut to the position as shown in the dotted line 75a Figure 11 In this case, each position where the lower surface side of the second component is cut is estimated in advance based on the elapsed time from the start to the end of film formation of the first layer 11 and the second layer 12 and the film formation speed of the first layer 11 and the second layer 12.

[0145] in addition, Figure 11 The third region 113 of the first layer 11 in the illustrated etched ring 1 is formed by cutting the second member from the center position of the circle of the substrate 5 a as a reference position to a predetermined position.

[0146] In addition, in the processing device, the upper surface side of the second member is cut with the lower end position of the base material 5a as the reference position so that the upper surface side of the second member becomes Figure 2 For example, the second part is cut to Figure 11 In this case, the position of the upper surface side of the second member is cut based on the elapsed time from the start to the end of the film formation of the first layer 11 and the second layer 12 and the film formation speed of the first layer 11 and the second layer 12.

[0147] The first component can be obtained by performing the same processing as the second component. Figure 2 Etched ring 1 with the structure shown.

[0148] In the second embodiment, as described above, the CVD film forming apparatus 4 is used to form the Figure 10 Then, the laminate 6a is processed by a processing device such as Figure 11 By processing the laminate 6a in this way, it is possible to obtain Figures 1 to 3 Etched ring 1 of the construction shown.

[0149] (Manufacturing process of etching ring 1)

[0150] Figure 12 This is a flow chart showing the manufacturing process of the etching ring 1 according to the second embodiment. Figure 12 For the purpose of realizing the above Figures 9 to 11 The flow of the manufacturing process of the manufacturing method of the etching ring 1 described in the above will be summarized and described.

[0151] about Figure 12The manufacturing process shown summarizes the method for manufacturing the etched ring 1 and is mainly explained to clarify the flow of the manufacturing process.

[0152] In the process of step S11, the second SiC layer 62 is formed around the substrate 5a in the CVD film forming device 4. Specifically, in the process of step S1, as described above, the second SiC layer 62 is formed around the substrate 5a. Figure 10 The second layer 62 is formed in the manner of the cross-sectional shape shown.

[0153] In the process of step S12, in the CVD film forming apparatus 4, the first layer 61 composed of SiC is formed around the second layer 62. Specifically, in the process of step S12, as described above, the first layer 61 composed of SiC is formed around the second layer 62. Figure 10 The first layer 61 is formed in the manner of the cross-sectional shape shown in FIG. By performing the process of step S11 and the process of step S12, the Figure 10 The laminated body 6a shown.

[0154] In step S13, the upper surface of the stacked body 6a is processed into a flat surface in the processing device, and the lower surface of the stacked body 6a is processed into a flat surface. In step S13, as described above, the upper and lower surfaces of the stacked body 6a are processed into flat surfaces by cutting the inner and outer circumferences of the stacked body 6a.

[0155] In step S14, the inner and outer circumferences of the substrate 5a are exposed in the processing apparatus. Specifically, in step S14, as described above, the inner circumference of the laminate 6a is cut to a first position predetermined with the center of the circle of the substrate 5a as a reference position. Furthermore, in step S14, as described above, the outer circumference of the laminate 6a is cut to a second position predetermined with the center of the circle of the substrate 5a as a reference position, thereby exposing the outer circumference of the substrate 5a.

[0156] In step S15, the base material 5a is removed in a processing device. Specifically, in step S15, the base material 5a is removed by chemical treatment as described above. Thus, the first and second components described above are obtained.

[0157] In the process of step S16, the processing device performs a cutting process for forming the first layer 11 and the second layer 12 on the portion of the first component or the second component that becomes the upper surface side of the etching ring 1, so that Figure 2 The layer thickness in the second region 112 of the first layer 11 shown is Figure 2 The second layer 12 is shown to have a thickness that is not exposed due to loss during etching.

[0158] Specifically, in the process of step S16, the processing device performs cutting of the first component or the second component with the lower end position of the substrate 5a as the reference position so that the portion of the first component or the second component that becomes the lower surface side of the etching ring 1 becomes Figure 2 The cross-sectional shape shown.

[0159] In the process of step S16, the processing device performs the processing of cutting the first component or the second component with the lower end position of the substrate 5a as the reference position so that the portion of the first component or the second component that becomes the lower surface side of the etching ring 1 becomes Figure 2 Thus, in the process of step S16 , the second layer 12 is processed so as to be present below the second region 112 in the first layer 11 .

[0160] In the second embodiment, by performing the manufacturing process as described above, it is possible to obtain Figure 1 and Figure 2 Etching ring 1 constructed as shown.

[0161] In the etching ring 1 of the second embodiment described above, the same technical effects as those of the first embodiment can be obtained.

[0162] [Implementation Method 3]

[0163] Next, use Figures 13 to 17 Embodiment 3 is described. In embodiment 3, for example, Figures 1 to 3 In the second region 112 of the illustrated first layer 11 , the thickness of the first layer 11 is such that the second layer 12 is not exposed due to loss during etching. Other structural examples will be described.

[0164] The main differences between Embodiment 3 and Embodiment 1 and Embodiment 2 are as follows: In Embodiment 3, the second layer 12a is stacked below the first layer 11a so that the second layer 12a does not exist below the second region 112a in the first layer 11a.

[0165] (Overall structure of etching ring 1a)

[0166] Figure 13 : is a cross-sectional view of the entire etching ring 1a in Embodiment 3. Figure 13 A cross section along the center line of the annular etched ring 1a is shown in FIG. Figure 14 1 is a partial cross-sectional view of the etching ring 1a of the embodiment 1. Figure 14 In, enlarged Figure 13 The cross section is shown on the right side of the etched ring 1a.

[0167] like Figure 13 and Figure 14 As shown, the etching ring 1a has a second layer 12a formed below the first layer 11a. The first layer 11a is made of SiC, similarly to the first layer 11. The second layer 12a is made of SiC, similarly to the second layer 12.

[0168] Figure 14 The structure and Figure 2 The structure of has the following corresponding relationship. The first area 111a and Figure 2 The second area 112a corresponds to the first area 111 of Figure 2 The third area 113a corresponds to the second area 112. Figure 2 The fourth area 114a corresponds to the third area 113. Figure 2 Corresponding to the fourth area 114 of the same.

[0169] The first surface 91a and Figure 2 The second surface 92a corresponds to the first surface 91. Figure 2 The third surface 93a corresponds to the second surface 92. Figure 2 The fourth surface 94a corresponds to the third surface 93. Figure 2 The second region 122a of the second layer 12 corresponds to the fourth surface 94 of Figure 2 The third region 123a of the second layer 12 corresponds to the second region 122. Figure 2 The interface 15a corresponds to the third region 123. Figure 2 etc. corresponds to interface 15.

[0170] Figure 13 and Figure 14 The etched ring 1a shown is Figure 1 The difference of the etched ring 1 is that, as Figure 14 Specifically, as shown, the second layer 12 a is not formed below the second region 112 a of the first layer 11 a .

[0171] like Figure 14 Specifically, the second layer 12a is stacked below the first layer 11a in a manner that it does not exist below the second region 112a of the first layer 11a. Figure 14 As shown, the second layer 12a is not formed below the first region 111a, the second region 112a, and the third region 113a in the first layer 11a, but is formed below the fourth region 114a in the first layer 11a. Therefore, the second layer 12a of the etching ring 1a in the third embodiment does not include Figure 2 The first region 121 of the second layer 12 is shown in FIG.

[0172] (Structure for Preventing Exposure of Second Layer 12 Due to Loss of First Layer 11 During Etching)

[0173] Figure 15 This is a cross-sectional view illustrating the loss of the first layer 11 during etching of the etching ring 1 a in the third embodiment.

[0174] In the etching device, when the wafer 2 is subjected to plasma etching, as shown in FIG. Figure 15 As shown, in the second region 112a, the first layer 11a is lost, creating a hole 3 and reducing the thickness of the first layer 11a. To prevent the second layer 12a from being exposed due to this etching loss, the first layer 11a is formed so that the thickness in the second region 112a is such that the second layer 12a is not exposed due to the etching loss. Furthermore, the second layer 12a does not exist below the second region 112a of the first layer 11.

[0175] Thus, in the etching ring 1 of the embodiment, the thickness of the second region 112a of the first layer 11a is formed to a thickness that prevents the second layer 12 from being exposed due to loss during etching, and the second layer 12a does not exist below the second region 112a of the first layer 11. Thus, in the etching ring 1a including the first layer 11 and the second layer 12, exposure of the second layer 12 during etching can be suppressed.

[0176] (Method for Manufacturing Etched Ring 1a)

[0177] Figure 16 1 is a cross-sectional view of the laminate 6 of the third embodiment, showing a portion of the etched ring 1a obtained by processing the laminate 6 using a processing device. Figure 16 As shown, in the stacked body 6, two etching rings 1a can be obtained.

[0178] In the method for manufacturing the etching ring 1a of the third embodiment, the method until forming the laminated body 6 in which the first layer 61 and the second layer 62 are laminated around the substrate 5 is the same as that used in the first embodiment. Figure 5 and Figure 6 The method of description is the same.

[0179] The following, to obtain Figure 16 The etching ring 1a shown at the bottom of the figure is a representative example, and the processing portion for obtaining the etching ring 1a will be described. In the processing device, the laminate 6 is processed as shown below to obtain Figure 13 Etched ring 1a with the structure shown.

[0180] In the case of obtaining the etched ring 1a shown at the bottom of the figure in the stacked body 6, the processing apparatus first performs a process of planarizing the lower surface of the stacked body 6 by cutting to a position indicated by, for example, a dotted line 71b, and a process of planarizing the upper surface of the stacked body 6 by cutting to a position indicated by, for example, a dotted line 72b. Thus, both end surfaces of the stacked body 6 in the stacking direction are planarized.

[0181] Next, in the processing device, the outer peripheral side of the stack 6 is cut to a position such as the dotted line 73b to expose the first area 51 of the substrate 5, and the inner peripheral side of the stack 6 is cut to a position such as the dotted line 74b to expose the second area 52 of the substrate 5.

[0182] In the process of exposing the first region 51 of the substrate 5, the outer circumference of the laminate 6 is cut to the same position as the predetermined outer circumference of the etching ring 1a as indicated by the dotted line 73b, with the center position of the circle of the substrate 5 as the reference position. In the process of exposing the second region 52 of the substrate 5, the inner circumference of the laminate 6 is cut to the same position as the predetermined inner circumference of the etching ring 1a as indicated by the dotted line 74b, with the center position of the circle of the substrate 5 as the reference position.

[0183] It should be noted that, in the process of exposing the first region 51 of the substrate 5, the laminate 6 only needs to be cut until at least the end portion on the outer peripheral side and the end portion on the inner peripheral side of the substrate 5 are exposed. Figure 16 The cutting position shown by the dotted line 73b and the Figure 16 Cutting at the position indicated by the dotted line 74 b may also be performed after the substrate 5 is removed.

[0184] Next, the base material 5 is removed by chemical treatment. Figure 16 The first part of the etched ring 1a shown on the underside is used to make Figure 16 The underside of the etched ring 1a is shown with the second component separated.

[0185] The following is for making Figure 16 The components of the etching ring 1a are shown on the lower side of FIG. 1 , and a processing method for manufacturing the etching ring 1a is described.

[0186] Will be used to make Figure 16 The second part of the etching ring 1a shown on the lower side is held in the processing part of the processing device in such a manner that the second layer 62 side planarized as described above faces downward. And, in the processing device, the thickness distribution of the first layer 11a in the radial direction of the etching ring 1a becomes Figure 2 The upper surface side of the etching ring 1a is cut and processed so as to obtain the thickness distribution shown.

[0187] Specifically, the interface 15a between the first layer 11a and the second layer 12a in the etching ring 1 becomes Figure 2 The cross-sectional shape shown in FIG is obtained by cutting the upper surface side of the second component with the lower end position of the substrate 5 as the reference position. For example, the second component is cut to Figure 16 The second part is cut to the position as shown in the dotted line 75b, or the second part is cut to the position as shown in the dotted line 75b Figure 16 In this case, each position where the upper surface side of the second component is cut is estimated in advance based on the elapsed time from the start to the end of film formation of the first layer 11a and the second layer 12a and the film formation speed of the first layer 11a and the second layer 12a.

[0188] in addition, Figure 14 The third region 113a of the first layer 11a in the illustrated etched ring 1a is formed by cutting the second member from the center position of the circle of the substrate 5 as a reference position to a predetermined position.

[0189] In addition, in the processing device, the lower end position of the base material 5 is used as a reference position, and the lower surface side of the second member is cut so that the lower surface side of the second member becomes Figure 14 For example, Figure 16 As shown by the dotted line 77b, the second part is cut until Figure 14 The first region 111a, the second region 112a, and the third region 113a of the first layer 11a shown are located at positions of the first layer 61a immediately before the second layer 62a. In this case, the position at which the lower surface of the second member is cut is estimated in advance based on the elapsed time from the start to the completion of film formation of the first layer 11a and the second layer 12a and the film formation speed of the first layer 11a and the second layer 12a.

[0190] Therefore, if Figure 14 As shown, the second layer 12a does not exist below the first region 111a, the second region 112a, and the third region 113a of the first layer 11a in the etched ring 1a.

[0191] The first component can be obtained by performing the same processing as the second component. Figure 14 Etched ring 1a with the structure shown.

[0192] In the third embodiment, as described above, the CVD film forming apparatus 4 is used to form the Figure 6 Then, the laminate 6 is processed by a processing device such as Figure 16 By processing the laminate 6 in this way, it is possible to obtain Figures 13 to 15 Etched ring 1a of the shown construction.

[0193] (Manufacturing Process of Etched Ring 1a)

[0194] Figure 17 This is a flow chart showing the manufacturing process of the etching ring 1a according to the third embodiment. Figure 17 For the purpose of realizing the above Figure 5 、 Figure 6 and Figure 16 The flow of the manufacturing process of the manufacturing method of the etching ring 1a described in the above will be summarized and described.

[0195] about Figure 17 The manufacturing process shown summarizes the method for manufacturing the etched ring 1 a and is mainly described to clarify the flow of the manufacturing process.

[0196] In the process of step S21, the first layer 61 of SiC is formed around the substrate 5 in the CVD film forming apparatus 4. The process of step S21 is the same as step S1 of the first embodiment.

[0197] In the process of step S22, the second layer 62 made of SiC is formed around the first layer 61 in the CVD film forming apparatus 4. The process of step S22 is the same as step S2 in the first embodiment.

[0198] In the process of step S23, the upper surface side of the stacked body 6 is processed into a flat surface in the processing device, and the lower surface side of the stacked body 6 is processed into a flat surface. The process of step S23 is the same as step S3 of the first embodiment.

[0199] In the process of step S24, the inner peripheral side and the outer peripheral side of the base material 5 are exposed in the processing device. The process of step S24 is the same as the process of step S4 in the first embodiment.

[0200] In the process of step S25, the base material 5 is removed in the processing device. The process of step S25 is the same as the process of step S25 in the first embodiment.

[0201] In the process of step S26, in the processing device, the first component or the second component is processed to form Figure 14 The layer thickness in the second region 112a of the first layer 11a shown becomes Figure 14 The second layer 12a shown is cut to such a thickness that the first layer 11a and the second layer 12a are not exposed due to loss during etching.

[0202] Specifically, in step S26 , as described above, the lower end position of the substrate 5 is used as a reference position, and the portion to be the upper surface of the etching ring 1 is cut by a predetermined thickness, thereby processing the surface on the first layer 11 a side.

[0203] In the process of step S26, the processing device performs the processing of cutting the first component or the second component with the lower end position of the substrate 5 as the reference position so that the portion of the first component or the second component that becomes the lower surface side of the etching ring 1a becomes Figure 14 Thus, in the process of step S26 , the second layer 12 is processed so as not to exist below the second region 112 in the first layer 11 .

[0204] In the third embodiment, by performing the manufacturing process as described above, it is possible to obtain Figure 13 and Figure 14 Etched ring 1a of the structure shown.

[0205] In the etching ring 1 a of the third embodiment described above, regarding the technology common to the first embodiment, the same technical effects as those of the first embodiment can be obtained.

[0206] In the etching ring 1 a of the third embodiment described above, the following unique technical effects can be obtained.

[0207] (1) In the etching ring 1a of embodiment 3, as Figure 14 and Figure 15 As shown, the second layer 12a is stacked below the first layer 11a so that the second layer 12a does not exist below the second region 112a in the first layer 11a. Thus, in the etching ring 1a including the first layer 11a and the second layer 12a, the second layer 12a does not exist below the first layer 11a, thereby preventing the second layer 12a from being exposed during etching.

[0208] (2) In the etching ring 1 of embodiment 3, as Figure 16 and Figure 17 As shown, the second layer 12a is processed so that the second layer 12a does not exist below the second region 112a of the first layer 11a. As a result, in the etching ring 1a including the first layer 11a and the second layer 12a, the second layer 12a does not exist below the first layer 11a, thereby preventing the second layer 12a from being exposed during etching.

[0209] [Implementation Method 4]

[0210] Next, use Figures 18 and 19 The fourth embodiment is described. In the fourth embodiment, Figures 13 to 15 Another method of manufacturing the etched ring 1a shown will be described.

[0211] The fourth embodiment differs from the third embodiment mainly in the following respects. In the fourth embodiment, a substrate 5a different from the substrate 5 in the third embodiment is used. In the fourth embodiment, a laminated body 6a having first layer 61a and second layer 62a laminated therein is formed in a different order than the first layer 61 and second layer 62 in the laminated body 6 in the third embodiment. In the fourth embodiment, the laminated body 6a is cut in a different order than the laminated body 6 in the third embodiment.

[0212] (Method for Manufacturing Etched Ring 1a)

[0213] Figure 18 1 is a cross-sectional view of the laminate 6 showing the portion of the etched ring 1a obtained by processing the laminate 6a of the fourth embodiment using a processing device. Figure 18 As shown, in the laminate 6a, two etching rings 1a can be obtained. Figure 18 In order to clarify the manufacturing range of one etching ring 1 a , the boundary between the manufacturing ranges of the two etching rings 1 a is indicated by a dashed line 70 .

[0214] In the fourth embodiment, as in the second embodiment, Figure 9 The substrate 5a shown is formed around Figure 10 After forming the second layer 62 shown, the first layer 61 is formed around the second layer 62, thereby forming the laminated body 6a.

[0215] In the method for manufacturing the etching ring 1a of the fourth embodiment, the method until forming the laminated body 6a in which the second layer 62 and the first layer 61 are laminated around the substrate 5 is the same as that used in the second embodiment. Figure 9 and Figure 10 The method of description is the same.

[0216] The following, to obtain Figure 18 The etching ring 1a shown in the figure below is a representative example, and the processing part for obtaining the etching ring 1a is explained. In the processing device, the stacked body 6a is processed as shown below to obtain Figure 14 Etched ring 1a with the structure shown.

[0217] In the case of obtaining the etched ring 1a shown at the bottom of the figure in the laminate 6a, the processing apparatus first performs a process of planarizing the lower surface of the laminate 6a by cutting to a position indicated by, for example, a dotted line 71a, and a process of planarizing the upper surface of the laminate 6a by cutting to a position indicated by, for example, a dotted line 72a. Thus, both end surfaces of the laminate 6a in the stacking direction are planarized.

[0218] Next, in the processing device, the outer peripheral side of the stack 6a is cut to a position such as the dotted line 73a to expose the second area 52a of the substrate 5a, and the inner peripheral side of the stack 6a is cut to a position such as the dotted line 74a to expose the first area 51a of the substrate 5a.

[0219] In the process of exposing the second region 52a of the substrate 5a, the outer circumference of the laminate 6a is cut to the same position as the predetermined outer circumference of the etching ring 1a indicated by the dotted line 73a, using the center position of the circle of the substrate 5a as the reference position. In the process of exposing the first region 51a of the substrate 5a, the inner circumference of the laminate 6a is cut to the same position as the predetermined inner circumference of the etching ring 1a indicated by the dotted line 74a, using the center position of the circle of the substrate 5a as the reference position.

[0220] It should be noted that in the process of exposing the first region 51a of the substrate 5a, the laminate 6a only needs to be cut until at least the end portion on the outer peripheral side and the end portion on the inner peripheral side of the substrate 5a are exposed, and the cutting to the position indicated by the dotted line 73a and the cutting to the position indicated by the dotted line 73a are performed. Figure 11 Cutting at the position indicated by the dotted line 74a can be performed after removing the substrate 5a.

[0221] Next, the substrate 5a is removed by chemical treatment. Figure 18 The first part of the etched ring 1a shown on the underside is used to make Figure 18 The underside of the etched ring 1a is shown with the second component separated.

[0222] The following is for making Figure 18 The components of the etching ring 1a are shown on the lower side of FIG. 1 , and a processing method for manufacturing the etching ring 1a is described.

[0223] Will be used to make Figure 18 The second part of the etching ring 1a shown on the lower side is held in the processing part of the processing device in such a manner that the first layer 61 side flattened as described above faces the vertical direction. And, in the processing device, the thickness distribution of the first layer 11 in the radial direction of the etching ring 1a becomes Figure 14 The upper surface side of the etching ring 1a is cut and processed so as to obtain the thickness distribution shown.

[0224] Specifically, Figure 14 The interface 15a between the first layer 11a and the second layer 12a in the etched ring 1a shown is formed. Figure 14 The lower surface side of the second component is cut with the lower end position of the substrate 5a as the reference position. For example, the second component is cut to Figure 18The second part is cut to the position as shown in the dotted line 75a, or the second part is cut to the position as shown in the dotted line 75a Figure 18 In this case, the positions at which the lower surface side of the second component is cut are estimated in advance based on the elapsed time from the start to the end of film formation of the first layer 11a and the second layer 12a and the film formation speed of the first layer 11a and the second layer 12a.

[0225] in addition, Figure 14 The third region 113a of the first layer 11a in the illustrated etched ring 1a is formed by cutting the second member from the center position of the circle of the substrate 5a as a reference position to a predetermined position.

[0226] In addition, in the processing device, the upper surface side of the second member is cut with the lower end position of the base material 5a as the reference position so that the upper surface side of the second member becomes Figure 14 For example, the second part is cut to Figure 18 In this case, the position where the upper surface side of the second component is cut is estimated in advance based on the elapsed time from the start to the end of the film formation of the first layer 11a and the second layer 12a and the film formation speed of the first layer 11a and the second layer 12a.

[0227] Therefore, if Figure 14 As shown, the second layer 12a does not exist below the first region 111a, the second region 112a, and the third region 113a of the first layer 11a in the etched ring 1a.

[0228] The first component can be obtained by performing the same processing as the second component. Figure 14 Etched ring 1a with the structure shown.

[0229] In the fourth embodiment, as described above, the CVD film forming apparatus 4 is used to form the Figure 10 Then, the laminate 6a is processed by a processing device such as Figure 18 By processing the laminate 6a in this way, it is possible to obtain Figures 13 to 15 Etched ring 1a with the structure shown.

[0230] (Manufacturing Process of Etched Ring 1a)

[0231] Figure 19 This is a flowchart showing the manufacturing process of the etching ring 1a according to the fourth embodiment. Figure 19 For the purpose of realizing the above Figure 9 、 Figure 10 as well as Figure 18 The flow of the manufacturing process of the manufacturing method of the etching ring 1a described in the above will be summarized and described.

[0232] about Figure 19 The manufacturing process shown summarizes the method for manufacturing the etched ring 1 a and is mainly described to clarify the flow of the manufacturing process.

[0233] In the process of step S31, the second layer 62 of SiC is formed around the substrate 5a in the CVD film forming apparatus 4. The process of step S31 is the same as step S11 of the second embodiment.

[0234] In the process of step S32, the first layer 61 made of SiC is formed around the second layer 62 in the CVD film forming apparatus 4. The process of step S32 is the same as step S12 in the second embodiment.

[0235] In step S33, the upper surface of the stacked body 6a is processed into a flat surface in a processing device, and the lower surface of the stacked body 6a is processed into a flat surface. The step S33 is the same as step S13 in the second embodiment.

[0236] In the process of step S34, the inner peripheral side and the outer peripheral side of the base material 5a are exposed in the processing device. The process of step S34 is the same as the process of step S14 in the second embodiment.

[0237] In the process of step S35, the base material 5a is removed in the processing device. The process of step S45 is the same as the process of step S15 in the second embodiment.

[0238] In the process of step S36, the first component or the second component is cut in the processing device to form the first layer 11a and the second layer 12a. Figure 14 The layer thickness in the second region 112a of the first layer 11a shown becomes Figure 14 The second layer 12a is shown to have a thickness that is not exposed due to loss during etching.

[0239] Specifically, in step S36 , as described above, the lower end position of the substrate 5 a is used as a reference position, and the portion to be the upper surface of the etching ring 1 a is cut by a predetermined thickness, thereby processing the surface on the first layer 11 side.

[0240] In the process of step S36, the processing device performs the processing of cutting the first component or the second component with the lower end position of the substrate 5a as the reference position so that the portion of the first component or the second component that becomes the lower surface side of the etching ring 1a becomes Figure 14 Thus, in the process of step S36 , the second layer 12 is processed so as not to exist below the second region 112 in the first layer 11 .

[0241] In the fourth embodiment, by performing the manufacturing process as described above, it is possible to obtain Figure 13 and Figure 14 Etched ring 1a of the structure shown.

[0242] In the etching ring 1 a of the fourth embodiment described above, the same technical effects as those of the first embodiment can be obtained with respect to the technology common to the first embodiment, and the same technical effects can be obtained with respect to the technology common to the third embodiment.

[0243] [Summary of Implementation Methods]

[0244] Next, the features of the embodiments of the present disclosure will be summarized and described.

[0245] (Item 1) An etching ring (etching ring 1, 1a) for holding a wafer (wafer 2) to be etched, comprising: a first layer (first layer 11, 11a) including a first region (first region 111, 111a) and a second region (second region 112, 112a) adjacent to the outer periphery of the first region (first region 111, 111a), the first layer (first layer 11, 11a) being formed to a thickness such that the second layer (second region 112, 112a) is not exposed due to loss during etching; and a second layer (second layer 12, 12a) being laminated below the first layer (first layer 11, 11a). Figure 2 The thickness of the first layer 11, Figure 14 The first layer 11a is formed in a manner having a thickness of (above).

[0246] With this structure, when etching is performed, in the second region, where the first layer is lost in the thickness direction, the first layer is formed to have a thickness such that the second layer is not exposed due to loss during etching. Thus, in the etching ring having the first and second layers, exposure of the second layer can be suppressed by the thickness of the first layer.

[0247] (Item 2) The etching ring according to Item 1, wherein the first layer (first layer 11, 11a) is formed thicker than the second layer (second layer 12, 12a) in the thickness direction of the second region (second region 112, 112a). Figure 2 、 Figure 14 ).

[0248] With this structure, the first layer is formed thicker than the second layer in the thickness direction of the second region. Thus, in the etching ring including the first and second layers, the second layer can be prevented from being exposed during etching by making the first layer thicker than the second layer.

[0249] (Item 3) The etching ring according to Item 1 or Item 2, wherein the second layer (second layer 12) is stacked below the first layer (first layer 11) in such a manner that the second layer (second layer 12) exists below the second region (second region 112) in the first layer (first layer 11). Figure 2 ).

[0250] With this structure, the second layer is stacked below the first layer so that the second layer exists below the second region in the first layer. Thus, in an etching ring comprising the first and second layers, the thickness of the first layer can suppress exposure of the second layer during etching, with respect to the second layer existing below the first layer.

[0251] (Item 4) The etching ring according to Item 1 or Item 2, wherein the second layer (second layer 12a) is stacked below the first layer (first layer 11a) in such a manner that the second layer (second layer 12a) does not exist below the second region (second region 112a) in the first layer (first layer 11a). Figure 14 ).

[0252] With this structure, the second layer is stacked below the first layer so that the second layer does not exist below the second region of the first layer. Thus, in the etching ring including the first and second layers, the second layer does not exist below the first layer, thereby preventing the second layer from being exposed during etching.

[0253] (Item 5) The etching ring according to any one of Items 1 to 4, wherein the first layer (first layer 11 , 11 a ) and the second layer (second layer 12 , 12 a ) are made of SiC.

[0254] According to such a structure, in the etching ring in which the first layer and the second layer are composed of SiC, it is possible to suppress exposure of the second layer during etching.

[0255] (Item 6) The etching ring according to any one of Items 1 to 5, wherein the second region (second region 112, 112a) in the first layer (first layer 11, 11a) is a region where the first layer (first layer 11, 11a) is lost in the thickness direction of the second region (second region 112, 112a) when the wafer (wafer 2) with its end portion held above the first region (first region 111, 111a) is etched. Figure 3 、 Figure 15 ).

[0256] According to such a structure, in the etching ring, in the region lost during etching, it is possible to suppress exposure of the second layer during etching.

[0257] (Item 7) The etching ring according to any one of Items 1 to 5, wherein the first layer (first layer 11, 11a) further includes a third region (third region 113, 113a) adjacent to the outer peripheral side of the second region (second region 112, 112a), and the third region (third region 113, 113a) has a protruding shape that faces the end of the wafer (wafer 2) when the end of the wafer (wafer 2) is held above the first region (first layer 11, 11a). Figure 2 、 Figure 14 . ).

[0258] According to such a configuration, in the etching ring, while holding the wafer, the outer periphery of the wafer can be surrounded by the third region.

[0259] (Item 8) A method for manufacturing an etching ring for holding an etched wafer (wafer 2), comprising: stacking a first layer (first layer 61, 11, first layer 61a, 61a) and a second layer (second layer 62, 12, second layer 62a, 12a) around an annular substrate (substrate 5, substrate 5a) (steps S1, S2, steps S11, S12, steps S21, S22, steps S31, S32); processing both end faces of the first layer (first layer 61, 11, first layer 61a, 11a) and the second layer (second layer 62, 12, second layer 62a, 12a) in the stacking direction into flat surfaces (steps S3, step S13, step S23, step S33); and making the first layer 61, 11, first layer 61a, 11a) and the second layer 62, 12, second layer 62a, 12a) flat. The steps of exposing the inner and outer peripheries of the substrate (substrate 5, 5a) (step S4, step S14, step S24, step S34); removing the substrate (substrate 5, 5a) (step S5, step S15, step S25, step S35); and processing the surface on one side of the end portion of the wafer (wafer 2) in the first layer (first layer 61, 11, first layer 61a, 11a), wherein the first layer (first layer 61, 11, first layer 61a, 11a) and the second layer (second layer 62, 12, second layer 62a, 12a) are stacked by forming one layer around the substrate and then forming another layer around the first layer (step S6, step S16, step S26, step S36). Figure 6 、 Figure 10), the first layer (first layer 61, 11, first layer 61a, 11a) is processed into a first region (first region 111, 111a) that includes an end portion of the wafer (wafer 2) and a second region (second region 112, 112a) adjacent to the outer peripheral side of the first region, and the layer thickness in the second region (second layer 62, 12, second layer 62a, 12a) is processed into a thickness that the second layer (second layer 62, 12, second layer 62a, 12a) will not be exposed due to loss in the etching (step S6, step S16, step S26, step S36).

[0260] According to this configuration, the first layer is processed so as to include a first region holding the end of the wafer and a second region adjacent to the outer periphery of the first region, and the first layer in the second region is processed so that the thickness of the first layer is such that the second layer is not exposed due to loss during etching. Thus, in the etching ring including the first and second layers, exposure of the second layer can be suppressed.

[0261] (Item 9) The method for manufacturing an etching ring according to Item 8, wherein the first layer (first layer 11, 11a) is processed in such a manner that the first layer (first layer 11, 11a) is thicker than the second layer (second layer 12, 12a) in the thickness direction of the second region (second region 112, 112a) (step S6, step S16, step S26, step S36).

[0262] With this structure, the first layer is processed in the thickness direction of the second region so that the first layer is thicker than the second layer. Thus, in the etching ring including the first and second layers, by making the first layer thicker than the second layer, the second layer can be prevented from being exposed during etching.

[0263] (Item 10) In the method for manufacturing an etching ring according to Item 8 or Item 9, the second layer (second layer 12) is processed in such a manner that the second layer (second layer 12) exists below the second region (second region 112) in the first layer (first layer 11) (step S6, step S16, step S26, step S36).

[0264] With this structure, the second layer is stacked below the first layer so that the second layer exists below the second region in the first layer. Thus, in an etching ring including the first and second layers, the thickness of the first layer can suppress exposure of the second layer during etching, with respect to the second layer existing below the first layer.

[0265] (Item 11) In the method for manufacturing an etching ring according to Item 8 or Item 9, the second layer (second layer 12a) is processed in such a manner that the second layer (second layer 12a) does not exist below the second region (second region 112a) in the first layer (first layer 11a) (step S6, step S16, step S26, step S36).

[0266] According to this structure, the second layer is processed so that it does not exist below the second region in the first layer. Thus, in the etching ring including the first and second layers, the second layer does not exist below the first layer, thereby preventing the second layer from being exposed during etching.

[0267] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present disclosure is not indicated by the description of the embodiments described above but by the scope of the claims, and is intended to include all modifications within the scope and equivalent meanings of the claims.

[0268] Description of Reference Numerals

[0269] 2: Chip

[0270] 1.1a: Etched ring

[0271] 111, 111a: First area

[0272] 112, 112a: Second area

[0273] 11, 11a, 61, 61a: First floor

[0274] 12, 12a, 62, 62a: Second layer

[0275] 113, 113a: Third area

[0276] 5.5a: substrate.

Claims

1. An etching ring for holding an etched wafer, characterized in that: have: a first layer including a first region and a second region adjacent to an outer peripheral side of the first region and holding an end portion of the wafer above the first region; a second layer, which is stacked below the first layer, The first layer includes the first region, the second region, the third region, and the fourth region in order from the inner circumference side. The first region is a region for holding an end portion of the wafer, The second region is located on the outer periphery of the first region and has the same thickness of the first layer as that of the first region. The fourth region is located on the outermost peripheral side and the thickness of the second layer is thicker than the thickness of the first layer. The side surface portion of the third region is perpendicular or inclined between the upper surface portion of the second region and the upper surface portion of the fourth region.

2. The etching ring according to claim 1, characterized in that The first layer and the second layer are composed of SiC.

3. The etching ring according to claim 1 or 2, characterized in that: The second region in the first layer is a region where the first layer is lost in the thickness direction of the second region when the wafer is etched while the end portion is held above the first region.

4. The etching ring according to claim 1 or 2, characterized in that: The third region has a protruding shape that faces the end of the wafer when the end of the wafer is held above the first region.

5. A method for manufacturing an etching ring for holding an etched wafer, characterized in that: The process includes the following steps: laminating a first layer and a second layer around the annular substrate; processing the two end surfaces of the first layer and the second layer in the stacking direction into flat surfaces; exposing the inner and outer peripheries of the substrate; removing the substrate; The surface of the first layer on the side of the end portion holding the wafer is processed, The first layer and the second layer are laminated by forming one layer around the substrate and then forming another layer around the one layer. The first layer includes a first region, a second region, a third region, and a fourth region in order from the inner circumference side. the second region is processed so as to be located on the outer peripheral side of the first region for holding the end of the wafer and to have the same thickness of the first layer as that of the first region; The fourth region located on the outermost peripheral side is processed so that the thickness of the second layer is thicker than the thickness of the first layer. The side surface portion of the third region is processed to be inclined between the upper surface portion of the second region and the upper surface portion of the fourth region.

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