RF-transmitting member

Abstract

The present invention provides an RF-permeable member that can easily remove reaction products adhering to the surface of a protective film. [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. Multiple grooves 210 are formed on the surface of the protective film 200.

Description

Technical Field

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

Background Art

[0002] For example, a semiconductor manufacturing apparatus such as an etching apparatus is provided with an RF transmission member. 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] When processes such as etching are repeated in a semiconductor manufacturing apparatus, reaction products generated by the reaction of plasma accumulate on the surface of the protective film. Such reaction products need to be periodically removed from the surface of the protective film. However, the adhesion of the reaction products to the surface of the protective film is relatively strong. Therefore, even if physical force is applied to the reaction products to remove them, it may not be easily removed in some cases.

[0006] This invention has been made in view of these problems, and its objective is to provide an RF-transmitting member that can easily remove reaction products adhering to the surface of a protective film. [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. Multiple grooves are formed on the surface of the protective film.

[0008] In the RF-transmitting member with the above configuration, multiple grooves are formed on the surface of the protective film, so the adhesion of reaction products to the surface is reduced compared to when no grooves are formed. Therefore, it becomes possible to easily remove the reaction products by applying physical force, etc. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an RF-permeable member that can easily remove reaction products adhering to the surface of a protective film. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of semiconductor manufacturing equipment. [Figure 2] This is a diagram showing a cross-section of the RF-transmitting member according to the first embodiment. [Figure 3] Figure 2 is a perspective view showing the shape of the RF-transmitting member. [Figure 4] This is a diagram illustrating an example of a method for forming a protective film on the inner surface of a cylindrical body. [Figure 5] This figure shows the configuration of the RF-transmitting member according to the second 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] A first embodiment will now be described. 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 interior of the RF transmission member 10 described below, becomes plasma, and is supplied into the chamber CM.

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

[0019] The cylindrical body 100 is a member that occupies most of the RF transmission member 10. The cylindrical body 100 is formed of a material through which the high-frequency radio wave (RF) generated by the coil CL described later can pass, for example, a ceramic material such as alumina. The cross-section of the cylindrical body 100 shown in Figure 2 is the cross-section when the cylindrical body 100 is cut along a plane including its central axis AX. The shape of the cylindrical body 100 is a shape obtained by rotating the cross-section shown in Figure 2 360 times 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] In the cylindrical body 100, a circular first opening 111 is formed at one end 110 along the central axis AX (the upper side in Figure 2). Also, in the cylindrical body 100, a circular second opening 121 is formed at the other end 120 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 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 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 such that the entire inner surface 130 is generally a concave curved surface. In the cross-section of FIG. 2, the portion of the curve representing the shape of the inner surface 130 to which the symbol "131" is attached protrudes in an arc shape toward the inside. Also, the portion of the curve to which the symbol "132" is attached protrudes in an arc shape toward the outside. The shape of the cylindrical body 100 does not need to be limited to such a shape, and various other shapes can be adopted.

[0024] 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.

[0025] As shown in Figures 2 and 3, multiple grooves 210 are formed on the entire surface of the protective film 200 (the surface opposite to the cylindrical body 100). Each groove 210 is formed to extend along the circumferential direction surrounding the central axis AX of the cylindrical body 100. Each groove 210 is parallel to the others. The spacing between adjacent pairs of grooves 210 (i.e., the groove 210 arrangement pitch) is, for example, about 0.5 mm. The dotted line DL shown in Figure 2 represents the shape of the inner surface 130 when no grooves 210 are formed.

[0026] When etching and other processes are repeated in the etching apparatus EQ, reaction products generated by the plasma reaction accumulate on the surface of the protective film 200. These reaction products need to be periodically removed from the surface of the protective film 200. However, the adhesion of the reaction products to the surface of the protective film 200 is relatively strong. Therefore, even if physical removal is attempted, it may not be easy to remove them.

[0027] Therefore, in the RF-transmitting member 10 according to this embodiment, a plurality of grooves 210 are formed in advance on the surface of the protective film 200, as described above. In this configuration, the adhesion force of the reaction product to the surface of the protective film 200 is reduced compared to when the grooves 210 are not formed. As a result, the reaction product can be easily removed from the protective film 200 by applying physical force or the like.

[0028] It is preferable to keep the depth of the groove 210 within 10 μm. By keeping the depth of the groove 210 to this extent, the difference in dielectric constant between the thick and thin parts of the protective film 200 becomes small. As a result, the influence of the groove 210 on the plasma state can be reduced to a negligible level. Since the intensity of high-frequency radio waves passing through each part of the protective film 200 becomes uniform, plasma can be generated uniformly inside the RF-transmitting member 10.

[0029] A method for forming the protective film 200 will be described with reference to Figure 4. The protective film 200 in this embodiment can be formed, for example, using the aerosol deposition method.

[0030] As is well known, in the aerosol deposition method, fine particles, which are the material for the protective film 200, are dispersed in a gas to form an "aerosol," which is then injected from a nozzle NZ towards the inner surface 130 of a cylindrical body 100 and collided with it. On the inner surface 130, the impact of the collision causes deformation and fragmentation of the fine particles, and as the fine particles combine with each other, they gradually accumulate to form the protective film 200.

[0031] The formation of the protective film 200 using the aerosol deposition method is performed, for example, by rotating the cylindrical body 100 at a constant speed around the central axis AX, as indicated by arrow AR1. When an aerosol is sprayed from the tip of the nozzle NZ toward the inner surface 130, as indicated by arrow AR2, the protective film 200 is formed circumferentially as the cylindrical body 100 rotates.

[0032] Subsequently, the spray angle of nozzle NZ is changed by a predetermined angle in the direction of arrow AR3, and then the protective film 200 is formed again at that position. The "predetermined angle" can be, for example, an angle such that the protective film 200 formed before the change in spray angle and the protective film 200 newly formed after the change in spray angle overlap in some areas. In the overlapping areas, the protective film 200 becomes thicker, and in the areas that do not overlap, the protective film 200 becomes thinner. Due to this difference in thickness, grooves 210 extending in the circumferential direction are formed on the surface of the protective film 200. By repeating the above process, a protective film 200 having multiple grooves 210 can be formed over the entire inner surface 130.

[0033] In addition to the aerosol deposition method described above, other methods such as physical vapor deposition (PVD) or chemical vapor deposition (CVD) may be used to form the protective film 200. When physical vapor deposition or the like is used, grooves 210 are not formed on the surface of the protective film 200 immediately after formation. In this case, after the protective film 200 is formed, grooves 210 as shown in Figures 2 and 3 can be formed on the surface of the protective film 200 by methods such as local grinding or polishing.

[0034] The multiple grooves 210 may be formed as grooves parallel to each other, as in this embodiment, but they may also be formed as, for example, intersecting grid-like grooves.

[0035] The second embodiment will now be described. The following will primarily focus on the differences from the first embodiment, while common points will be omitted as appropriate.

[0036] In this embodiment, the direction in which the grooves 210 extend in the protective film 200 differs from that of the first embodiment. Figure 5 schematically shows the RF-transmitting member 10 according to this embodiment as viewed from the second opening 121 side along the central axis AX. As shown in the figure, the grooves 210 in this embodiment are formed to extend in a direction perpendicular to the circumferential direction surrounding the central axis AX of the cylindrical body 100. In other words, the direction in which the grooves 210 extend in this embodiment is generally perpendicular to the direction in which the grooves 210 extend in the first embodiment. Even with this configuration, the same effects as those described in the first embodiment can be achieved.

[0037] A protective film 200 like that of this embodiment can also be formed using the aerosol deposition method. For example, the process can be repeated by continuously moving the nozzle NZ at a constant speed in the direction of arrow AR3 in Figure 4 while forming the film, and then rotating the cylindrical body 100 by a predetermined angle in the direction of arrow AR1 in Figure 4.

[0038] The "predetermined angle" mentioned above can be, for example, an angle such that the protective film 200 formed before rotating the cylindrical body 100 and the protective film 200 newly formed after rotating the cylindrical body 100 partially overlap each other. In the overlapping portion, the protective film 200 becomes thicker, and in the non-overlapping portion, the protective film 200 becomes thinner. Due to this difference in thickness, grooves 210 extending from the surface of the protective film 200 can be formed as shown in Figure 5.

[0039] In this embodiment as well, instead of the above-described film formation method, the protective film 200 may be formed using, for example, physical vapor deposition (PVD) or chemical vapor deposition (CVD). When physical vapor deposition or the like is used, grooves 210 are not formed on the surface of the protective film 200 immediately after film formation. Therefore, in this case, after the protective film 200 is formed, grooves 210 as shown in Figure 5 can be formed on the surface of the protective film 200 by methods such as local grinding or polishing.

[0040] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise. [Explanation of symbols]

[0041] 10: RF-transmitting member 100: Cylindrical body 111: First opening 121: Second opening 130: Inner self 200: Protective film 210: Groove 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. The RF-transmitting member is characterized in that a plurality of grooves are formed on the surface of the protective film.

2. The RF-transmitting member according to claim 1, characterized in that the groove is formed to extend along the circumferential direction surrounding the central axis of the cylindrical body.

3. The RF-transmitting member according to claim 1, characterized in that the groove is formed to extend along a direction perpendicular to the circumferential direction surrounding the central axis of the cylindrical body.

4. The RF-transmitting member according to claim 1, characterized in that the depth of the groove is 10 μm or less.

5. The RF-transmitting member according to claim 1, characterized in that the protective film is a film formed using an aerosol deposition method.

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