RF-transmitting member

Abstract

The present invention provides an RF-transmitting member that can prevent damage to the protective film caused by residual stress. [Solution] The RF-transmitting member 10 comprises a cylindrical body 100 and a protective film 200 covering the inner surface 130 of the cylindrical body 100. A first opening 111 is formed at one end of the cylindrical body 100, and a second opening 121 with a larger inner diameter than the first opening 111 is formed at the other end of the cylindrical body 100. In a cross-section when the cylindrical body 100 is cut along a plane including its central axis AX, the inner surface 130 of the cylindrical body 100 includes a first region D1 that protrudes inward in an arc shape, and a second region D2 that is located on the second opening 121 side of the first region D1 and protrudes outward in an arc shape. In the above cross-section, the curvature of the first region D1 is greater than the curvature of the second region D2, and the protective film 200 covering the first region D1 is thinner than the protective film 200 covering the second region D2.

Description

Technical Field

[0006] , ,

[0005] , ,

[0001] The present invention relates to an RF transmission member.

Background Art

[0002] For example, in a semiconductor manufacturing apparatus such as an etching apparatus, an RF transmission member is provided. The RF transmission member is a member that transmits high-frequency radio waves (RF) generated by an outer coil into an inner space to generate plasma in the space. As described in Patent Document 1 below, in recent years, an RF transmission member having a cylindrical shape has also been proposed and has already been put into practical use.

[0003] In such an RF transmission member, an opening formed at one end of the cylindrical body is used as a gas inlet, and an opening formed at the other end is used as a plasma outlet. The inner surface of the cylindrical body is covered with a protective film for protecting the cylindrical body from plasma. As the material of the cylindrical body, for example, alumina or the like is used. As the material of the protective film, for example, yttria or the like is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the protective film, stress generated during film formation or the like often remains as residual stress. As the curvature of the inner surface of the cylindrical body increases, the residual stress of the protective film covering the portion tends to increase. Also, as the protective film becomes thicker, the residual stress of the protective film tends to increase. Therefore, depending on the shape of the inner surface of the cylindrical body and the thickness of the protective film, etc., the residual stress may become too large, and there is a possibility that the protective film may be damaged or peeled off.

[0006] This invention has been made in view of these problems, and its objective is to provide an RF-transmitting member that can prevent damage to the protective film caused by residual stress. [Means for solving the problem]

[0007] To solve the above problems, the RF-transmitting member according to the present invention comprises a cylindrical body and a protective film covering the inner surface of the cylindrical body. A first opening is formed at one end of the cylindrical body, and a second opening with a larger inner diameter than the first opening is formed at the other end of the cylindrical body. In a cross-section when the cylindrical body is cut by a plane including the central axis, the inner surface of the cylindrical body includes a first region that protrudes inward in an arc shape, and a second region that is on the second opening side of the first region and protrudes outward in an arc shape. In the above cross-section, the curvature of the first region is greater than the curvature of the second region, and the protective film covering the first region is thinner than the protective film covering the second region.

[0008] The first region of the inner surface of the cylindrical body has a large curvature in its cross-section, making it a region where large residual stresses tend to remain in the protective film. Therefore, by making the thickness of the protective film covering this first region thin, the residual stress in the protective film can be suppressed. As a result, damage to the protective film caused by residual stress can be prevented. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an RF-transmitting member that can prevent damage to the protective film caused by residual stress. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of semiconductor manufacturing equipment. [Figure 2] This figure shows a cross-section of the RF-transmitting member according to this embodiment. [Modes for carrying out the invention]

[0011] This embodiment will now be described with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.

[0012] The RF-transmitting member 10 according to this embodiment is used in semiconductor manufacturing equipment such as a plasma etching apparatus. Before describing the RF-transmitting member 10, the configuration of the semiconductor manufacturing equipment will be described first.

[0013] Figure 1 schematically shows the configuration of an etching apparatus EQ, which is an example of semiconductor manufacturing equipment. The etching apparatus EQ is a device for selectively removing a portion of a film that has been pre-formed on the surface of a substrate W to be processed, using plasma. The etching apparatus EQ comprises a chamber CM, a pump PM, a chuck section EC, a gas supply section GS, and an RF permeable member 10.

[0014] The chamber CM is a container that houses the chuck portion EC and the like inside. The etching process on the substrate W is performed inside the chamber CM. Among the components that make up the chamber CM, the upper component (top plate) in Figure 1 has an opening OP formed therein, and the shower plate SH and RF transparent member 10, which will be described later, are provided to cover the opening OP from above.

[0015] Pump PM is a device for reducing the pressure inside the chamber CM. By using Pump PM to expel gas from inside the chamber CM, the pressure inside the chamber CM is reduced to a pressure suitable for plasma generation and etching.

[0016] The chuck unit EC is a device that supports the substrate W from below. For example, an electrostatic chuck that uses electrostatic force to attract and fix the substrate W is used as the chuck unit EC. The chuck unit EC is mounted on a support base SB located inside the chamber CM.

[0017] The gas supply unit GS is a device that supplies the gas necessary for plasma generation. The gas from the gas supply unit GS is supplied into the RF-transmitting member 10, which will be described next, and becomes plasma which is then supplied into the chamber CM.

[0018] The RF permeable member 10 is a cylindrical member that connects the gas supply unit GS and the chamber CM. As shown in Figure 2, the RF permeable member 10 comprises a cylindrical body 100 and a protective film 200.

[0019] The cylindrical body 100 is a component that makes up the majority of the RF-transmitting member 10. The cylindrical body 100 is made of a material that can transmit high-frequency radio waves (RF) generated by the coil CL described later, such as a ceramic material such as alumina. The cross-section of the cylindrical body 100 shown in Figure 2 is the cross-section obtained when the cylindrical body 100 is cut by a plane containing its central axis AX. The shape of the cylindrical body 100 is obtained by rotating the cross-section shown in Figure 2 360 degrees around the central axis AX. Therefore, the cross-sectional shape when the cylindrical body 100 is cut perpendicular to the central axis AX is circular regardless of the height position of the cut surface.

[0020] A circular first opening 111 is formed at one end 110 of the cylindrical body 100, along the central axis AX (the upper side in Figure 2). A circular second opening 121 is formed at the other end 120 of the cylindrical body 100, along the central axis AX (the lower side in Figure 2). The inner diameter of the second opening 121 is larger than the inner diameter of the first opening 111.

[0021] As shown in FIG. 1, the end portion 110 is connected to the end of a supply pipe extending from the gas supply unit GS. The end portion 120 is connected to the chamber CM via the shower plate SH. The shower plate SH is a plate-like member provided so as to cover the entire opening OP and is formed of metal. The shower plate SH covers the entire second opening 121 from the lower side and covers the entire opening OP from the upper side. A plurality of through holes HL are formed in the shower plate SH. The internal space of the cylindrical body 100 and the internal space of the chamber CM communicate with each other via the through holes HL.

[0022] A coil CL is disposed outside the cylindrical body 100. The coil CL is for generating high-frequency radio waves necessary for plasma generation. When an alternating voltage is applied between the coil CL and the support base SB, the generated high-frequency radio waves penetrate the cylindrical body 100 and enter its internal space. The gas supplied from the gas supply unit GS into the cylindrical body 100 is ionized by the high-frequency radio waves and becomes plasma containing a large number of particles such as radicals. The plasma enters the chamber CM through the through holes HL of the shower plate SH and is used for processes such as etching of the substrate W. A part of the supplied gas may become plasma after entering the chamber CM through the through holes HL.

[0023] As shown in FIG. 2, the cylindrical body 100 is a dome-shaped member in which the entire inner surface 130 is generally a concave curved surface. In the cross section of FIG. 2, the portion marked with the symbol "D1" and the region in the vicinity of the curve representing the shape of the inner surface 130 are regions that protrude in an arc shape toward the inside. The region of the inner surface 130 that has the above-described shape in the cross section of FIG. 2 is hereinafter also referred to as the "first region D1". Here, the "toward the inside" as described above means "toward the direction approaching the central axis AX".

[0024] In the cross-section of Figure 2, the portion of the curve representing the shape of the inner surface 130 labeled "D2" and the surrounding area are located below the first region D1 (i.e., towards the second opening 121) and are regions that protrude outward in an arc shape. The region of the inner surface 130 that has the shape described above in the cross-section of Figure 2 will also be referred to as the "second region D2" below. In the above, "outward" means "away from the central axis AX".

[0025] In the cross-section shown in Figure 2, the curvature of the curve representing the shape of the first region D1 is greater than the curvature of the curve representing the shape of the second region D2. In other words, the radius of curvature of the curve representing the shape of the first region D1 is smaller than the radius of curvature of the curve representing the shape of the second region D2.

[0026] The protective film 200 is a film formed to cover the entire inner surface 130 of the cylindrical body 100. The protective film 200 is provided as a film to protect the inner surface 130 of the cylindrical body 100 from plasma. The protective film 200 is formed of a material that has resistance to plasma, for example, a material mainly composed of yttria. The thickness of the protective film 200 is appropriately set according to the length of time for which resistance to plasma is required. In this embodiment, the thickness of the protective film 200 is approximately 10 μm. The protective film 200 can be formed, for example, using the aerosol deposition method. The protective film 200 may also be formed using physical vapor deposition (PVD) or chemical vapor deposition (CVD).

[0027] Incidentally, the protective film 200 often retains residual stress from the stress generated during its formation. In the cross-section shown in Figure 2, the greater the curvature of the inner surface 130, the greater the residual stress in the protective film 200 covering that portion tends to be. Also, the thicker the protective film 200, the greater the residual stress tends to be. Therefore, depending on the shape of the inner surface 130 and the thickness of the protective film 200, the residual stress may become too large, potentially causing damage or peeling of the protective film 200.

[0028] Therefore, in the RF-transmitting member 10 of this embodiment, damage to the protective film 200 caused by residual stress is prevented by devising the thickness distribution of the protective film 200 that covers each part of the inner surface 130.

[0029] As shown in the enlarged view labeled "B" in Figure 2, the thickness of the protective film 200 covering the second region D2 is T2. Also, as shown in the enlarged view labeled "A" in Figure 2, the thickness of the protective film 200 covering the first region D1 is T1, which is smaller than T2. ​​In other words, in this embodiment, the thickness distribution of the protective film 200 covering each part of the inner surface 130 is adjusted so that the protective film 200 covering the first region D1 is thinner than the protective film 200 covering the second region D2. The thickness adjustment can be done, for example, by varying the amount of polishing when polishing the surface after the formation of the protective film 200 is complete.

[0030] The first region D1 of the inner surface 130 has a large curvature in the cross-section shown in Figure 2, and is therefore a region where large residual stresses tend to remain in the protective film 200. By making the thickness of the protective film 200 covering this first region D1 thin, the residual stress in the protective film 200 can be suppressed. As a result, damage to the protective film 200 caused by residual stress can be prevented.

[0031] It is preferable that the thickness (T1) of the protective film 200 covering the first region D1 be 20 μm or less. Experiments conducted by the inventors have confirmed that setting T1 to such a thickness in Figure 2 sufficiently reduces the residual stress of the protective film 200 in the first region D1.

[0032] When AC power is supplied to the coil CL, a phenomenon called sputtering is likely to occur in the portion of the protective film 200 near the coil CL, where a part of the protective film 200 is scraped off due to radical collisions. Therefore, if the protective film 200 is made too thin, there is a possibility that the protective film 200 will deteriorate in a relatively short period of time.

[0033] Therefore, it is preferable that the thickness (T2) of the portion of the protective film 200 covering the second region D2 is 5 μm or more. Under the condition of T1 < T2, if T2 in FIG. 2 is set to such a thickness, it has been confirmed by experiments and the like conducted by the inventors that the durability of the protective film 200 in the second region D2 can be sufficiently enhanced.

[0034] The thickness of the portion of the protective film 200 covering the first region D1 and the thickness of the portion covering the second region D2 may change discontinuously or may change smoothly between the two.

[0035] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. As long as those obtained by appropriately making design changes to these specific examples by those skilled in the art have the features of the present disclosure, they are included in the scope of the present disclosure. Each element included in each of the above-described specific examples and its arrangement, conditions, shape, etc. are not limited to those illustrated and can be changed as appropriate. Each element included in each of the above-described specific examples can be appropriately combined as long as no technical contradiction occurs.

Explanation of Reference Numerals

[0036] 10: RF transmission member 100: Cylindrical body 111: First opening 121: Second opening 130: Inner surface 200: Protective film D1: First region D2: Second region AX: Central axis

Claims

1. A cylindrical body, An RF-transmitting member comprising a protective film covering the inner surface of the cylindrical body, A first opening is formed at one end of the cylindrical body. A second opening with a larger inner diameter than the first opening is formed at the other end of the cylindrical body. In the cross-section obtained by cutting the cylindrical body with respect to the plane including the central axis, The inner surface of the cylindrical body is The first region protrudes inward in an arc shape, The second region is a portion of the first region that is on the second opening side and protrudes outward in an arc shape, The curvature of the first region is greater than the curvature of the second region. An RF-transmitting member characterized in that the protective film covering the first region is thinner than the protective film covering the second region.

2. The RF-transmitting member according to claim 1, characterized in that the thickness of the protective film covering the first region is 20 μm or less.

3. The RF-transmitting member according to claim 1, characterized in that the thickness of the protective film covering the second region is 5 μm or more.

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