Plasma treatment unit

Abstract

Even if the dielectric plate is damaged, the vacuum of the vacuum container is maintained. The plasma processing device (101) includes: a vacuum container (1) whose interior is evacuated by vacuum; an antenna (3) disposed outside the vacuum container, which generates plasma inside the vacuum container (1) by flowing a high-frequency current; a dielectric plate (5) that blocks the opening (1a) formed in the vacuum container (1) facing the antenna (3); and a sheet member (6) that covers the dielectric plate (5) from the outside of the vacuum container (1) and has insulation. The periphery of the sheet member (6) is fixed around the area in the vacuum container (1) where the dielectric plate (5) is disposed.

Description

[Technical Field]

[0001] This disclosure relates to a plasma processing apparatus. [Previous Technology]

[0002] A plasma processing apparatus using inductively coupled plasma is known, which introduces a high-frequency electric field generated by an antenna disposed outside a vacuum container through a dielectric window provided in the vacuum container. For example, Patent Document 1 describes a plasma processing apparatus in which a dielectric window is formed by comprising a slit plate and a dielectric plate, the slit plate blocking an opening of the vacuum container formed at a position facing the antenna, and the dielectric plate blocking a slit formed in the slit plate from the outside of the vacuum container. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2021-111595 [Summary of the Invention]

[0004] [Problem to be solved by the invention] However, in the plasma processing apparatus disclosed in Patent Document 1, if the dielectric plate is damaged, the vacuum of the vacuum container cannot be maintained depending on the degree of damage.

[0005] The purpose of this disclosed embodiment is to maintain the vacuum in the vacuum container even if the dielectric plate is damaged. [Means of Problem Solving]

[0006] To solve the aforementioned problem, one aspect of the plasma processing apparatus disclosed herein includes: a vacuum container, the interior of which is evacuated by a vacuum; an antenna disposed outside the vacuum container, wherein plasma is generated inside the vacuum container by flowing a high-frequency current; a dielectric plate blocking an opening formed in the vacuum container facing the antenna; and a sheet member covering the dielectric plate from the outside of the vacuum container and having insulating properties, the periphery of the sheet member being fixed around the area in the vacuum container where the dielectric plate is disposed. [Effects of the Invention]

[0007] With the form disclosed herein, the vacuum of the vacuum container can be maintained even if the dielectric plate is damaged.

Implementation Method

[0009] [Embodiment 1] Hereinafter, Embodiment 1 of the present disclosure will be described in detail.

[0010] <Structure of the Plasma Processing Apparatus> FIG1 is a longitudinal sectional view showing the structure of the plasma processing apparatus 101 of this embodiment. FIG2 is a plan view showing the structure of the plasma processing apparatus 101. FIG3 is a longitudinal sectional view showing the structure of the main parts of the plasma processing apparatus 101.

[0011] As shown in Figures 1 to 3, the plasma treatment apparatus 101 is an apparatus that uses an inductively coupled plasma P to perform carburizing, nitriding, ashing, etching, film formation, and other treatments on the workpiece 20. A bias voltage is applied to the workpiece 20.

[0012] The plasma processing apparatus 101 includes a vacuum container 1, a vacuum exhaust device 2, an antenna 3 (plasma generating unit), a high-frequency power supply 4, a dielectric plate 5, a sheet component 6, a retaining frame 7, and a plurality of bolts 8. Furthermore, the plasma processing apparatus 101 includes a gasket 9 (first sealing component) and an O-ring 10 (second sealing component) as sealing components.

[0013] The vacuum container 1 is a container in which gas G, which serves as a plasma source, is introduced. The interior of the vacuum container 1 is evacuated by a vacuum exhaust device 2. The vacuum container 1 is, for example, made of metal and electrically grounded.

[0014] An opening 1a, in a rectangular shape, is formed on the upper wall of the vacuum container 1, extending through the thickness direction of the upper wall. The opening 1a is formed at a position facing the antenna 3, which will be described later. Around the opening 1a, an opening edge 1b is provided, each having a predetermined width along both the short and long sides of the opening 1a. The opening edge 1b is formed at a position lower than the outer surface of the upper wall of the vacuum container 1.

[0015] An exhaust pipe 1c is provided on the bottom wall of the vacuum container 1. The exhaust pipe 1c is a pipe connecting the interior of the vacuum container 1 to the vacuum exhaust device 2. A gate valve (not shown) is disposed between the vacuum exhaust device 2 and the exhaust pipe 1c. The gate valve is an adjustable valve. The exhaust volume of the vacuum exhaust device 2 is adjusted by adjusting the opening of the gate valve. By adjusting the exhaust volume, the vacuum level inside the vacuum container 1 is adjusted.

[0016] A gas inlet 1d is provided on the side wall of the vacuum container 1 to introduce gas G into the interior of the vacuum container 1. Oxygen (O2) or nitrogen (N2) is used as gas G.

[0017] The antenna 3 generates an induced electric field by using high-frequency power supplied from the high-frequency power source 4 to induce a high-frequency current flow. This causes plasma to be generated inside the vacuum container 1. The antenna 3 has a straight body and curved ends on both sides of the body. The antenna 3 is positioned outside the vacuum container 1, near the dielectric plate 5, with its body facing the opening 1a. The high-frequency power source 4 is connected to one end of the antenna 3, and the other end is grounded. The antenna 3 is made of materials such as copper, aluminum, their alloys, or stainless steel, but may also be made of other materials.

[0018] Furthermore, the antenna 3 is not limited to one; multiple antennas may be provided. When multiple antennas 3 are provided, they are arranged in parallel with intervals between them.

[0019] The high-frequency power supply 4 is a power source that supplies high-frequency power to the antenna 3. The frequency of the high-frequency power is, for example, a typical 13.56 MHz, but is not limited to this.

[0020] The dielectric plate 5 is disposed on the edge of the opening 1b in an unfixed state by blocking the opening 1a. The dielectric plate 11b is a plate-shaped component that is entirely composed of dielectric material and is formed of ceramic, inorganic material, resin material, etc.

[0021] The sheet member 6 is a sheet-like member covering the outside of the vacuum container 1 with a dielectric plate 5, and it has insulating properties. The sheet member 6 is formed from a polyimide film such as Kapton (registered trademark) or a resin such as Teflon (registered trademark). Preferably, the material of the sheet member 6 has a dielectric tangent of 0.01 or less, and more preferably, a dielectric tangent of 0.005 or less. By forming it from a material with a dielectric tangent of 0.01 or less, excessive heating of the sheet member 6 can be suppressed.

[0022] The peripheral portion 6a of the sheet member 6 is fixed to the area around the opening edge 1b in the vacuum container 1 where the dielectric plate 5 is disposed, by means of bolts 8, by pressing the dielectric plate 5. Furthermore, the sheet member 6 is fixed to the vacuum container 1 by bolts 8, thereby airtightly covering the dielectric plate 5. The sheet member 6 has bolt holes 6b for fixing by means of bolts 8.

[0023] The retaining frame 7 is a metal frame-like member with an opening 7a of approximately the same size and shape as the outer peripheral end of the opening edge 1b formed on its inner side. The retaining frame 7 is disposed around the opening edge 1b on the outer surface of the upper wall of the vacuum container 1, with the opening 7a approximately coinciding with the opening 1a. The retaining frame 7 is fixed to the vacuum container 1 by bolts 8, thereby holding the sheet member 6 by pressing down on the peripheral edge 6a from above.

[0024] Bolts 8 are spaced apart on the retaining frame 7. The shaft portion 8a of the bolt 8 is inserted through the through hole 7b in the retaining frame 7 and the bolt hole 6b in the sheet member 6. By fastening the bolts to the upper wall of the vacuum container 1, the sheet member 6 and the retaining frame 7 are fixed to the upper wall of the vacuum container 1.

[0025] The gasket 9 is a frame-shaped structure with approximately the same size as the lower surface of the retaining frame 7. The gasket 9 is positioned between the periphery 6a of the sheet member 6 and the upper wall of the vacuum container 1. The gasket 9 seals the sheet member 6 and the vacuum container 1. To improve the sealing performance, two gaskets 9 may be overlapped with a spacer between them, or a thickened gasket 9 may be provided.

[0026] The O-ring 10 is disposed between the lower surface of the dielectric plate 5 in the periphery and the opening edge 1b of the vacuum container 1. The O-ring 10 seals the dielectric plate 5 and the vacuum container 1.

[0027] 〈Effects of the sheet component〉 Figure 4 is a plan view showing an enlarged portion of the sheet component 6 provided in the plasma processing apparatus 101.

[0028] In the plasma processing apparatus 101 configured as described above, the dielectric plate 5 is covered by the sheet member 6. Therefore, even if the dielectric plate 5 suffers damage such as cracks, the damaged area is covered by the sheet member 6. Thus, even if the dielectric plate 5 is damaged, the vacuum inside the vacuum container 1 can be maintained by the sheet member 6.

[0029] The sheet component 6 airtightly covers the dielectric plate 5. The sheet component 6 is held by the retaining frame 7 by the fastening of the bolts 8, thereby being subjected to tension to airtightly cover the dielectric plate 5. In this way, when the dielectric plate 5 is damaged and air can pass through the damaged area, the sheet component 6 can block the damaged area by adsorption.

[0030] Furthermore, if the sheet member 6 is relatively loosely covering the dielectric plate 5 without being secured by the bolts 8 and is pressed down by the retaining frame 7, then when the dielectric plate 5 is damaged and air can pass through the damaged area, the sheet member 6 may sometimes have difficulty adhering to the damaged area. Therefore, it is preferable that the sheet member 6 airtightly covers the dielectric plate 5 by securing it with the bolts 8. However, if the retaining frame 7 applies a certain degree or more of external pressure to the sheet member 6, the sheet member 6 will adhere to the damaged area. Therefore, in this case, it is not necessarily possible to airtightly cover the dielectric plate 5.

[0031] The sheet member 6 is fixed to the vacuum container 1 by pressing the dielectric plate 5. This ensures that the dielectric plate 5 remains in the vacuum container 1 even when simply disposed without being fixed to it. This also ensures the sealing of the periphery 6a of the sheet member 6. Furthermore, it adequately ensures the fixing strength of the dielectric plate 5. Moreover, even if the internal pressure of the vacuum container 1 increases due to the displacement of the gas G inside the vacuum container 1, causing the dielectric plate 5 to attempt to float, it is prevented from floating. Therefore, floating or detachment of the dielectric plate 5 is prevented.

[0032] The peripheral portion 6a of the sheet member 6 is fixed to the vacuum container 1 by bolts 8. A gasket 9 seals the peripheral portion 6a of the sheet member 6 with the vacuum container 1. An O-ring 10 seals the dielectric plate 5 with the opening edge 1b of the vacuum container 1. This improves the sealing performance between the peripheral portion 6a of the sheet member 6 and the vacuum container 1. Furthermore, it improves the sealing performance between the dielectric plate 5 and the opening edge 1b. Moreover, it suppresses the pressure rise inside the vacuum container 1 that is prone to occur when the dielectric plate 5 is damaged.

[0033] Furthermore, the sheet member 6 becomes flat when the vacuum container 1 is vented by the vacuum venting device 2. However, the peripheral portion 6a of the sheet member 6 will shift due to the expansion and contraction of the washer 9 and the O-ring 10. Therefore, as shown in FIG4, the bolt hole 6b of the sheet member 6 is formed as an elongated hole in the direction in which the peripheral portion 6a shifts relative to the shaft portion 8a of the bolt 8 in response to the expansion and contraction of the washer 9 and the O-ring 10. Moreover, the bolt hole 6b is formed to be longer than (greater than) the range W in which the peripheral portion 6a shifts relative to the shaft portion 8a in response to the aforementioned expansion and contraction.

[0034] Therefore, even if the periphery 6a of the sheet member 6 is displaced due to the expansion and contraction of the washer 9 and the O-ring 10, the periphery 6a can be displaced without being hindered by the bolt 8. Thus, deformation and damage of the sheet member 6 due to the expansion and contraction of the washer 9 and the O-ring 10 are difficult to occur.

[0035] <Modifications> Modifications to this embodiment will be described below. Furthermore, for ease of explanation, constituent elements that have the same function as those described in this embodiment will be marked with the same symbols, and their descriptions will not be repeated.

[0036] FIG5 is a longitudinal sectional view showing the structure of the plasma treatment apparatus 102 of this modified example. FIG6 is a longitudinal sectional view showing the structure of the main parts of the plasma treatment apparatus 102.

[0037] As shown in Figures 5 and 6, in the plasma processing apparatus 102, the opening 1a of the vacuum container 1 in the plasma processing apparatus 101 is replaced with two openings 1e. The dielectric plate 5 in the plasma processing apparatus 102 is formed by splicing two basic dielectric plates 5A.

[0038] Furthermore, the plasma processing apparatus 102 replaces the O-ring 10 in the plasma processing apparatus 101 and includes two O-rings 11. The O-rings 11 are arranged such that they are spaced between the lower surface of the peripheral portion of the basic dielectric plate 5A and the opening edge 1b of the vacuum container 1. The O-rings 11 seal between the basic dielectric plate 5A and the vacuum container 1.

[0039] Furthermore, the opening 1e, the basic dielectric plate 5A and the O-ring 11 are not limited to two, as long as there are multiple.

[0040] In the plasma processing apparatus 102 configured as described above, basic dielectric plates 5A are spliced ​​together to form a dielectric plate 5, thereby allowing the dielectric plate 5 to be formed into a large size. Furthermore, if insulation failure occurs at the splicing points of the basic dielectric plates 5A in the dielectric plate 5, the splicing points will become surfaces, and discharge (surface discharge) can easily occur between the antenna 3 and the opening edge 1b via these surfaces. To address this, a sheet member 6 is used to cover the dielectric plate 5 formed from multiple basic dielectric plates 5A, thereby preventing the insulation failure. Moreover, similar to the plasma processing apparatus 101, even if the dielectric plate 5 is damaged, the vacuum inside the vacuum container 1 can be maintained by the sheet member 6 in the plasma processing apparatus 102.

[0041] [Summary] The plasma processing apparatus of the first aspect disclosed herein includes: a vacuum container, the interior of which is evacuated by a vacuum; an antenna disposed outside the vacuum container, which generates plasma inside the vacuum container by flowing a high-frequency current; a dielectric plate that blocks an opening formed in the vacuum container at a position facing the antenna; and a sheet member that covers the dielectric plate from the outside of the vacuum container and is insulating, the periphery of the sheet member being fixed around the area in the vacuum container where the dielectric plate is disposed.

[0042] In the structure described, the dielectric plate is covered by a sheet member, thereby ensuring that even if the dielectric plate is damaged, the damaged portion is covered by the sheet member. Therefore, even if the dielectric plate is damaged, the vacuum of the vacuum container can be maintained by the sheet member.

[0043] The plasma processing apparatus of the second aspect disclosed herein may also be, in the first aspect, wherein the sheet member hermetically covers the dielectric plate.

[0044] According to the structure, when the dielectric plate is damaged and air can pass through the damaged part, the sheet component can block the damaged part by adsorption.

[0045] The plasma processing apparatus of the third aspect disclosed herein may also be, in the first aspect, fixed to the vacuum container by pressing the dielectric plate.

[0046] In the structure described, the sheet member presses against the dielectric plate, thereby holding the dielectric plate in the vacuum container without fixing it. Therefore, the sealing at the periphery of the sheet member can be ensured, and the fixing strength of the dielectric plate can also be sufficiently ensured. Furthermore, when the internal pressure of the vacuum container increases, the dielectric plate is prevented from floating.

[0047] The plasma processing apparatus of the fourth aspect disclosed herein may also be, in the first aspect, formed by splicing together multiple basic dielectric plates.

[0048] In the structure described, the dielectric plate can be formed into a large size. Moreover, the sheet material component can prevent insulation damage that is prone to occur at the joints of multiple basic dielectric plates.

[0049] The plasma processing apparatus of the fifth aspect disclosed herein may also be, in any of the first to fourth aspects, wherein the peripheral portion of the sheet member is fixed to the vacuum container by bolts, the dielectric plate is disposed on the opening edge around the opening in the vacuum container, and the plasma processing apparatus further includes: a first sealing member, which is spaced between the peripheral portion of the sheet member and the vacuum container; and a second sealing member, which is spaced between the dielectric plate and the opening edge.

[0050] According to the structure described above, the sealing performance between the periphery of the sheet member and the vacuum container, as well as the sealing performance between the dielectric plate and the opening edge, can be improved. Furthermore, the pressure rise inside the vacuum container when the dielectric plate breaks can be suppressed.

[0051] The plasma processing apparatus of the sixth aspect disclosed herein may also be, in any of the first to fourth aspects, wherein the peripheral portion of the sheet member has a bolt hole through which the shaft portion of the bolt is inserted, and the bolt hole is formed to be larger than the range by which the peripheral portion is displaced relative to the bolt in response to the expansion and contraction of the first sealing member and the second sealing member.

[0052] According to the structure, if the periphery of the sheet member is displaced due to the expansion and contraction of the first sealing member and the second sealing member, the periphery can be displaced without being hindered by the bolts.

[0053] [Notes] This disclosure is not limited to the described embodiments, and various modifications can be made within the scope shown in the request. Moreover, embodiments obtained by appropriately combining the technical components disclosed in the embodiments are also included within the technical scope of this disclosure. [Simplified Explanation of the Diagram]

[0008] FIG1 is a longitudinal sectional view showing the structure of a plasma treatment apparatus according to one embodiment of the present disclosure. FIG2 is a plan view showing the structure of the plasma treatment apparatus. FIG3 is a longitudinal sectional view showing the structure of the main part of the plasma treatment apparatus. FIG4 is an enlarged plan view showing a portion of the sheet member provided in the plasma treatment apparatus. FIG5 is a longitudinal sectional view showing the structure of a modified example of the plasma treatment apparatus. FIG6 is a longitudinal sectional view showing the structure of the main part of the plasma treatment apparatus shown in FIG5.

Claims

1. A plasma treatment apparatus, comprising: Vacuum container, the interior of which is vented by vacuum; An antenna, located outside the vacuum container, generates plasma inside the vacuum container by flowing a high-frequency current; a dielectric plate blocks an opening in the vacuum container formed at a position facing the antenna; The sheet member covers the dielectric plate from the outside of the vacuum container and is insulating. The dielectric plate is disposed on an opening edge formed around the opening. The opening edge is formed at a position lower than the outer surface of the upper wall of the vacuum container. The peripheral portion of the sheet member is fixed to the area around the opening edge in the outer surface of the upper wall of the vacuum container.

2. The plasma treatment apparatus as claimed in claim 1, wherein, The sheet component airtightly covers the dielectric plate.

3. The plasma treatment apparatus as claimed in claim 1, wherein, The sheet component is fixed to the vacuum container by pressing the dielectric plate.

4. The plasma treatment apparatus as claimed in claim 1, wherein, The dielectric plate is formed by splicing together multiple basic dielectric plates.

5. The plasma treatment apparatus as described in any one of claims 1 to 4, wherein, The periphery of the sheet member is fixed to the vacuum container by bolts, and the plasma treatment apparatus further includes: a first sealing member, which is separated between the periphery of the sheet member and the vacuum container; and a second sealing member, which is separated between the dielectric plate and the opening edge.

6. The plasma treatment apparatus as claimed in claim 5, wherein, The periphery of the sheet member has a bolt hole through which the shaft portion of the bolt is inserted. The bolt hole is formed to be larger than the range by which the periphery is displaced relative to the bolt in response to the expansion and contraction of the first sealing member and the second sealing member.

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