Plasma processing apparatus and reaction tube wall protection member

Abstract

The invention provides a plasma processing apparatus and a reaction tube wall protection member capable of suppressing consumption of a reaction tube. The plasma processing apparatus can perform plasma processing on a substrate in a reaction tube, and comprises: a cylindrical reaction tube; a substrate holder which can be inserted into and removed from the reaction tube and which can place a plurality of substrates on a plurality of layers; a pair of electrodes disposed on the outside of the reaction tube and disposed so as to face each other across the center of the reaction tube; a high-frequency power source capable of applying high-frequency electric power to one or one side of the pair of electrodes to generate plasma in the reaction tube; and a pair of reaction tube wall protection members disposed between the pair of electrodes, the pair of reaction tube wall protection members including a first reaction tube wall protection member disposed between one electrode and the substrate holder and a second reaction tube wall protection member disposed between the other electrode and the substrate holder. The pair of reaction tube wall protection members is provided so as to cover an inner wall surface of the reaction tube facing an outer wall surface on which the pair of electrodes is provided.

Description

Technical Field

[0001] This invention relates to plasma processing apparatus and reaction tube wall protection components. Background Technology

[0002] Patent Document 1 discloses a plasma processing apparatus having a plasma generation section extending in the height direction of a reaction tube. Furthermore, it discloses that the plasma generation section has a hollow protrusion and a pair of plasma electrodes disposed on a pair of walls of the hollow protrusion. Additionally, it discloses that due to plasma sputtering and etching, large stresses are generated along and near the outline of the plasma electrodes on the walls of the hollow protrusion.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 4329403 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] One aspect of the present invention provides a plasma processing apparatus and a reaction tube wall protection component capable of suppressing the consumption of the reaction tube.

[0008] Means for solving technical problems

[0009] To address the aforementioned technical problems, according to one aspect of the present invention, a plasma processing apparatus is provided, capable of performing plasma processing on a substrate within a reaction tube. The plasma processing apparatus includes: a cylindrical reaction tube; a substrate holder capable of being inserted and removed relative to the reaction tube, which can hold multiple substrates on multiple layers; a pair of electrodes disposed on the outer side of the reaction tube, arranged opposite each other across the center of the reaction tube; a high-frequency power supply capable of applying high-frequency electrical power to one or both of the electrodes to generate plasma within the reaction tube; and a pair of reaction tube wall protection members disposed between the electrodes, each having a first reaction tube wall protection member disposed between one electrode and the substrate holder, and a second reaction tube wall protection member disposed between the other electrode and the substrate holder, the pair of reaction tube wall protection members being arranged to cover the inner wall surface of the reaction tube opposite to the outer wall surface used to house the pair of electrodes.

[0010] Invention Effects

[0011] According to one aspect of the present invention, a plasma processing apparatus and a reaction tube wall protection component can be provided that can suppress the consumption of the reaction tube. Attached Figure Description

[0012] Figure 1 This is a longitudinal cross-sectional structural diagram showing an example of a plasma processing device.

[0013] Figure 2 The diagram, viewed along the direction of arrow A, is a longitudinal cross-sectional view of an example plasma processing device.

[0014] Figure 3 This is a cross-sectional structural diagram showing an example of a plasma processing device in the BB section.

[0015] Figure 4 This is an example of a longitudinal cross-sectional view of a reaction tube equipped with a reaction tube wall protection component.

[0016] Figure 5 This is an example of a front view of the reaction tube wall protection component, seen from the radial outside of the reaction tube.

[0017] Figure 6 This is an example of a top view of a component protecting the reaction tube wall.

[0018] Figure 7 This is a cross-sectional structural diagram showing an example of the configuration of the reaction tube and the reaction tube wall protection components.

[0019] Figure 8 This is a diagram representing an example of the Paschen curve.

[0020] Explanation of reference numerals in the attached figures

[0021] W substrate, 1 reaction tube, 1a, 1b electrode mounting parts, 1d lower flange, 1e opening port, 2 top plate, 3 wafer boat (substrate holder), 4 rod, 5 insulation cylinder, 6 stage, 7 cover, 8 rotation axis, 9 magnetic fluid seal, 10 sealing component, 11 arm, 12 exhaust port, 20 gas supply pipe, 31, 31A, 31B electrodes, 32 impedance matching device, 33 high frequency power supply, 50 heating mechanism, 51 heater wire, 60 shielding component, 70 control unit, 100 reaction tube wall protection component, 110 reaction tube wall protection plate, 110a~100c plate-shaped parts, 115 protrusion, 120 base part, 125 fixing shaft. Detailed Implementation

[0022] Hereinafter, the embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals are sometimes used to refer to the same components, and repeated descriptions are omitted.

[0023] [Plasma Processing Device]

[0024] use Figures 1 to 3 The plasma processing apparatus (substrate processing apparatus) of this embodiment will be described. Figure 1 This is a longitudinal cross-sectional structural diagram showing an example of a plasma processing device. Figure 2 It is along Figure 1 The diagram shown, viewed in the direction of arrow A, is a longitudinal cross-sectional structural diagram representing an example of a plasma processing device. Figure 3 It means Figure 2 A cross-sectional structural diagram of an example plasma processing device in the BB section is shown. Figures 1 to 3 The plasma processing apparatus shown is a batch processing apparatus capable of performing substrate processing (e.g., film deposition) on multiple substrates W. Furthermore, in Figure 1 and Figure 2 The illustration of the reaction tube wall protection component 100 (reaction tube wall protection plate 110) described later is omitted.

[0025] The plasma processing device has a topped cylindrical reaction tube (also called a processing container or reactor) 1 with an opening at the bottom. The reaction tube 1 is formed entirely of, for example, quartz. A top plate 2 made of quartz is disposed near the upper end inside the reaction tube 1, and the area below the top plate 2 is sealed.

[0026] The reaction tube 1 has a cylindrical shape (circular shape) that is closed at the top. Additionally, the reaction tube 1 has an opening at the bottom, allowing a wafer boat (substrate holder) 3 to be inserted into or removed from the reaction tube 1 from below. The wafer boat (substrate holder) 3 can hold multiple (e.g., several to about 100) semiconductor wafers (hereinafter referred to as "substrate W") as substrates to be processed on multiple layers. As described above, within the reaction tube 1, wafers can be arranged in a vertical direction at intervals L. W Multiple substrates W are roughly horizontally arranged in a space 1c. The wafer boat 3 is formed of quartz, for example. The wafer boat 3 has four rods 4 (see reference). Figure 3 ,exist Figure 1 , 2 The diagram shows two rods (not shown), which can support multiple substrates W using grooves (not shown) formed on rod 4.

[0027] The wafer boat 3 is placed on the stage 6 via a quartz-insulated cylinder 5. The stage 6 is supported on a rotating shaft 8, which passes through a metal (stainless steel) cover 7 for opening and closing the lower end of the reaction tube 1.

[0028] A magnetic fluid seal 9 is provided at the through portion of the rotating shaft 8 to airtightly seal the rotating shaft 8 and to support the rotating shaft 8 in a rotatable manner. A sealing member 10 is provided between the periphery of the cover 7 and the lower end of the reaction tube 1 to maintain the airtightness of the reaction tube 1.

[0029] The rotating shaft 8 is mounted at the front end of the arm 11, which is supported by a lifting mechanism (not shown), such as a boat lift. The wafer boat 3 and the cover 7 can be raised and lowered as a single unit, allowing insertion and removal relative to the reaction tube 1. Alternatively, the stage 6 can be fixedly mounted on the side of the cover 7, allowing the substrate W to be processed without rotating the wafer boat 3.

[0030] In addition, the plasma processing apparatus has a gas supply unit for supplying specified gases such as processing gas and purging gas into the reaction tube 1.

[0031] The gas supply section includes a gas supply pipe 20. The gas supply pipe 20, for example, is made of quartz and extends vertically, penetrating the sidewall of the reaction tube 1 and curving upwards. In the vertical portion of the gas supply pipe 20, a plurality of vents 20g are formed at predetermined intervals along a length corresponding to the wafer support area of ​​the wafer boat 3. Each vent 20g can release gas in the horizontal direction. Processing gas can be supplied from a gas supply source (not shown) to the gas supply pipe 20 via a gas piping. A flow controller (not shown) and an on / off valve (not shown) are provided on the gas piping. Thus, processing gas from the gas supply source can be supplied to the reaction tube 1 via the gas piping and the gas supply pipe 20. The flow controller can control the flow rate of gas supplied from the gas supply pipe 20 to the reaction tube 1. The on / off valve can control the supply / stopping of gas supplied from the gas supply pipe 20 to the reaction tube 1.

[0032] In addition, Figure 3 The diagram shows four gas supply pipes 20, but the number of gas supply pipes 20 is not limited to this. Alternatively, it can be a structure in which four gas supply pipes 20 supply different gases to the reaction tube 1, or a structure in which at least two or more gas supply pipes 20 supply the same gas to the reaction tube 1.

[0033] A pair of electrodes 31A and 31B are disposed on the outer side of the reaction tube 1. The electrodes 31A and 31B are each formed of a flat plate and are disposed on electrode mounting portions 1a and 1b, which are located on the outer side of the reaction tube 1. Furthermore, the electrodes 31A and 31B are arranged opposite each other, separated from the center of the reaction tube 1 (the center of the substrate W supported by the wafer boat 3). That is, the electrodes 31A and 31B are positioned at a position rotated 180° circumferentially around the reaction tube 1. Additionally, the electrodes 31A and 31B are arranged parallel to each other. The electrode mounting portions 1a and 1b can be integrally formed with the reaction tube 1 or separately formed from it.

[0034] Electrodes 31A and 31B are formed of good conductors such as metals. Furthermore, nickel alloys are preferably used as the material for electrodes 31A and 31B. By using nickel alloys as the material for electrodes 31A and 31B, compared to using copper, the influence of metal contamination (diffusion of metal atoms into the quartz-formed reaction tube 1) on the reaction tube 1 can be suppressed. In addition, nickel alloys have high heat resistance, allowing use within the operating temperature range of the plasma processing apparatus (the temperature heated by the heating mechanism 50 described later, for example, from room temperature to 900°C). Furthermore, nickel alloys have oxidation resistance.

[0035] Each electrode 31A, 31B is connected to a high-frequency power supply 33 via an impedance matching device 32. The high-frequency power supply 33 and the impedance matching device 32 constitute a high-frequency control system. The high-frequency control system can apply impedance-matched high-frequency power to each electrode 31A, 31B. The high-frequency power applied from the impedance matching device 32 to the electrodes 31A, 31B has, for example, voltages that are opposite in phase (phase difference of 180°) and have the same voltage amplitude and frequency. In other words, the matching circuit of the impedance matching device 32 is determined in such a way that the voltages are opposite in phase (phase difference of 180°) and have the same voltage amplitude and frequency. Therefore, a high Vpp (maximum amplitude difference of electrode voltage) can be obtained with low power. Furthermore, in Figure 1 , Figure 2 The diagram illustrates a structure in which high-frequency electrical power is supplied from a set of impedance matching devices 32 and a high-frequency power supply 33 to each electrode 31A, 31B, but the structure is not limited to this. Alternatively, it could be a structure with separate impedance matching devices 32 and 33 for supplying high-frequency electrical power to electrode 31A, and another for supplying high-frequency electrical power to electrode 31B. Furthermore, it could be a structure where high-frequency electrical power is supplied from the high-frequency power supply 33 to one side of the pair of electrodes 31A, 31B via the impedance matching device 32, while the other electrode 31B is grounded.

[0036] The power supply lines for electrodes 31A and 31B are preferably connected to the center of the electrodes. This allows high-frequency electrical power to be applied to the center of electrodes 31A and 31B.

[0037] The frequency of the high-frequency electrical power applied to electrodes 31A and 31B can be in the range of 1kHz to 100MHz. In addition, in order to suppress the influence of the wavelength of the voltage standing wave generated on the electrodes on the film formation process (substrate processing), the frequency of the high-frequency electrical power applied to electrodes 31A and 31B is preferably a frequency of 40MHz or less.

[0038] The inside of the reaction tube 1 is vented and depressurized (vacuum atmosphere) by the exhaust device 42 (described later). Additionally, processing gas is supplied to the inside of the reaction tube 1 from the gas supply pipe 20. On the other hand, the outside of the reaction tube 1 is in atmospheric atmosphere. Electrodes 31A and 31B are disposed in the atmospheric space outside the reaction tube 1.

[0039] By applying high-frequency electrical power from each high-frequency power source 33 to each electrode 31A, 31B, an electric field is formed within the reaction tube 1, generating capacitively coupled plasma (CCP) within the reaction tube 1. Furthermore, multiple substrates W within the reaction tube 1 are held by a wafer boat 3 in a manner that creates space in the height direction. Additionally, by applying high-frequency electrical power to electrodes 31A, 31B, capacitively coupled plasma is generated within the reaction tube 1. That is, plasma can be generated in the space between the substrates W. Here, the spacing L between the substrates W... W Preferably, the spacing is 10 mm or more. This improves the in-plane uniformity of the plasma generated in the space between the substrates W. Furthermore, considering the productivity of substrate processing using a plasma processing apparatus and the size of the reaction tube 1, the substrate spacing is preferably in the range of 15 mm to 40 mm.

[0040] like Figure 1 and Figure 2 As shown, electrodes 31A and 31B are arranged in a height direction over a range larger than the range in the height direction of the plurality of substrates W mounted in the wafer boat 3. In other words, the amplitude L in the height direction of electrodes 31A and 31B is... E The range is wider in the height direction than the plurality of substrates W placed in the wafer boat 3. That is, electrodes 31A and 31B are formed at a position higher than the uppermost substrate W placed in the wafer boat 3, and electrodes 31A and 31B are formed at a position lower than the lowermost substrate W placed in the wafer boat 3.

[0041] like Figure 3 As shown, electrode 31A is configured such that, in the width direction (horizontal direction), the two ends of electrode 31A in the horizontal direction are connected to the center of reaction tube 1 (the center of substrate W supported by wafer boat 3) at an angle θ. W Within the range of 20° to 60°. Additionally, the angle θ... W More preferably, the range is 25° to 40°.

[0042] Furthermore, the width of electrode 31B is equal to the width of electrode 31A. Additionally, the pair of electrodes 31A and 31B are arranged opposite each other, separated by the center of the reaction tube 1 (the center of the substrate W supported by the wafer boat 3), and are arranged parallel to each other. Thus, the electric field direction 300 formed by the two electrodes 31A and 31B is... Figure 3 The arrow in the image indicates this. For example... Figure 3 As shown, a uniform electric field can be formed on the substrate W.

[0043] Furthermore, in the relationship between the heating mechanism 50 (heater wire 51) and the reaction tube 1 described later, electrodes 31A and 31B shield the radiant heat from the heating mechanism 50 (heater wire 51) to the reaction tube 1. Therefore, the circumferential length of the reaction tube 1 shielded by electrodes 31A and 31B is preferably, for example, less than 1 / 3 of the full circumference. In other words, the angle θ W Preferably, the angle is 60° or less. Furthermore, considering the power density of electrodes 31A and 31B, the angle θ... W The preferred range is 25° to 60°.

[0044] An exhaust port 12 for venting vacuum from the reaction tube 1 is provided on the side wall portion. A pressure control valve 41 for controlling the pressure inside the reaction tube 1 and an exhaust device (exhaust unit) 42 including a vacuum pump are connected to the exhaust port 12, and the exhaust device 42 can be used to vent the reaction tube 1 through the exhaust pipe.

[0045] Additionally, a thermocouple 13 is disposed along the inner wall of reaction tube 1 (see reference). Figure 3 Multiple thermocouples 13 are arranged in the height direction. The control unit 70 uses the thermocouples 13 to detect the temperature, and the detected temperature is used for temperature control of the substrate W.

[0046] In addition, such as Figure 3 As shown, the gas supply pipe 20 and the thermocouple 13 are configured to avoid the electric field (within the range of electric field direction 300) formed by the electrodes 31A and 31B.

[0047] A cylindrical heating mechanism 50 is provided around the reaction tube 1. The heating mechanism 50 has a wound heater wire 51. The heater wire 51 is arranged to surround the reaction tube 1 and a plurality of electrodes 31A, 31B. Furthermore, the space between the heating mechanism 50 and the reaction tube 1 is atmospheric, and the electrodes 31A, 31B are disposed in this space. The heating mechanism 50 is capable of heating the reaction tube 1 and the substrate W inside it. The heating mechanism 50 can be controlled to make the temperature of the reaction tube 1 reach the desired temperature. Thus, the substrate W inside the reaction tube 1 can be heated by radiant heat from the wall of the reaction tube 1, etc. In addition, the temperature of the reaction tube 1 heated by the heating mechanism 50 is, for example, in the range of room temperature to 900°C. In addition, in the film formation process, the temperature of the reaction tube 1 is, for example, in the range of 150°C to 600°C. In addition, in the film formation process, the temperature of the reaction tube 1 is preferably used in the range of, for example, 200°C to 500°C.

[0048] Additionally, a shield 60 is provided on the outside of the heating mechanism 50. That is, the shield 60 is arranged to surround the reaction tube 1, the plurality of electrodes 31A, 31B, and the heating mechanism 50. The shield 60 is formed of a good conductor such as metal and is grounded.

[0049] In addition, the plasma processing apparatus includes a control unit 70. The control unit 70 controls, for example, the operation of various parts of the plasma processing apparatus, the supply / stopping of various gases via the opening and closing of valves, the control of gas flow rate via a flow controller, and the exhaust control via the exhaust device 42. Furthermore, the control unit 70 controls, for example, the on / off switching of high-frequency electrical power via the high-frequency power supply 33, and the temperature control of the reaction tube 1 and the substrate W inside it via the heating mechanism 50.

[0050] The control unit 70 may be, for example, a computer. Furthermore, the computer program that performs the operations of each part of the plasma processing apparatus is stored in a storage medium. The storage medium may be, for example, a floppy disk, optical disk, hard disk, flash memory, DVD, etc.

[0051] By employing the structure described above, the plasma processing apparatus can depressurize the reaction tube 1 using the exhaust device 42, supply processing gas into the reaction tube 1 from the gas supply pipe 20, and apply high-frequency electrical power to the electrodes 31A and 31B, thereby generating capacitively coupled plasma (CCP) within the reaction tube 1 to process the substrate W (film deposition, etching, etc.). Furthermore, capacitively coupled plasma can also be generated in the space 1c between the substrates W. This improves the uniformity of free radicals and active species generated by the plasma in both the central and peripheral regions of the substrate W. Additionally, it allows for the generation and supply of sufficient concentrations of free radicals and active species for substrate processing in both the central and peripheral regions of the substrate W.

[0052] Here, as Figures 1-3 As shown, in the plasma processing apparatus of this embodiment, electrodes 31A and 31B are arranged to clamp the reaction tube 1, and plasma is generated inside the reaction tube 1.

[0053] The plasma formed inside the reaction tube 1 is capacitively coupled plasma (CCP). Therefore, the inner walls of the electrode mounting sections 1a and 1b of the reaction tube 1 are damaged by the plasma. Specifically, the inner walls of the electrode mounting sections 1a and 1b of the reaction tube 1 are damaged by ion sputtering and ion-assisted etching, etc. In particular, when the plasma-generating gas is an oxygen-free gas containing hydrogen, large localized stresses are generated at the boundary between the plasma-damaged portion and the surrounding undamaged portion.

[0054] This stress will be generated at the inner end of the hundreds of μm thick inner wall surface layer that has been damaged by plasma, and will be locally present in the range of 100 μm to 200 μm in thickness. Due to the large stress generated in this localized area, the quartz-formed reaction tube 1 may be damaged, potentially shortening its lifespan.

[0055] In this regard, in the plasma processing apparatus of this embodiment, such as Figure 3 As shown, a reaction tube wall protection member 100 is provided inside the reaction tube 1. The reaction tube wall protection member 100 is arranged along the inner wall surface of the electrode setting portions 1a and 1b for setting electrodes 31A and 31B. That is, between a pair of opposing electrodes 31A and 31B, one reaction tube wall protection member 100 is arranged between the substrate W and one electrode setting portion 1a for setting one electrode 31A, and another reaction tube wall protection member 100 is arranged between the substrate W and another electrode setting portion 1b for setting the other electrode 31B. This prevents ions from plasma formed on the substrate from entering the inner wall surface of the electrode setting portions 1a and 1b of the reaction tube 1, thereby suppressing the consumption of the reaction tube 1.

[0056] use Figures 4-6 Further explanation of the reaction tube wall protection component 100. Figure 4 This is an example of a longitudinal cross-sectional view of a reaction tube 1 equipped with a reaction tube wall protection component 100. Figure 5 This is an example of a front view of the reaction tube wall protection component 100, viewed from the radially outer side of the reaction tube 1. Figure 6 This is an example of a top view of the reaction tube wall protection member 100. Furthermore, in the following description, the reaction tube wall protection member 100 provided on the electrode setting section 1a side will be used as an example, but the reaction tube wall protection member 100 provided on the electrode setting section 1b side also has the same structure, and repeated descriptions will be omitted.

[0057] The reaction tube wall protection component 100 includes a reaction tube wall protection plate 110, a protrusion 115, a base portion 120, and a fixing shaft 125. Furthermore, the surface of the reaction tube wall protection plate 110 facing the center of the reaction tube 1 is referred to as the surface side, and the surface facing the inner wall surface of the reaction tube 1 is referred to as the back side side.

[0058] The reaction tube wall protection plate 110 is a separate component from the side wall of the reaction tube 1, and is made of synthetic quartz glass with an OH group concentration of 200 ppm or higher. Therefore, compared to components made of, for example, high-purity electrofused quartz glass, ion sputtering and ion-assisted etching of the reaction tube wall protection plate 110 can be suppressed, thus preventing the generation of localized stress on the surface of the reaction tube wall protection plate 110. Consequently, damage to the reaction tube wall protection plate 110 due to this stress can be prevented. That is, the replacement frequency of the reaction tube wall protection plate 110 can be reduced.

[0059] Furthermore, a reaction tube wall protection plate 110 is disposed in the space between the inner wall surface of the electrode placement section 1a and the substrate W, covering the electrode placement section 1a. That is, the reaction tube wall protection plates 110 are respectively disposed to cover the inner wall surface (inner wall surface side of electrode placement sections 1a and 1b) opposite to the outer wall surface (outer wall surface side of electrode placement sections 1a and 1b) used for placing a pair of electrodes 31A and 31B. This prevents ions from the plasma formed on the substrate W from entering the inner wall surface of the electrode placement sections 1a and 1b. Therefore, damage to the inner wall surface of the electrode placement sections 1a and 1b due to ion sputtering and ion-assisted etching can be prevented, suppressing the generation of localized stress on the surface of the electrode placement sections 1a and 1b. Furthermore, even when the reaction tube 1 is made of, for example, high-purity electrofused silica glass, the consumption of the reaction tube 1 can be suppressed.

[0060] Furthermore, if the entire reaction tube 1 is made of synthetic quartz glass with an OH group concentration of 200 ppm or higher, the cost of reaction tube 1 will increase from the perspective of material supply and processing difficulty. Similarly, if the electrode mounting sections 1a and 1b in reaction tube 1 are made of synthetic quartz glass with an OH group concentration of 200 ppm or higher, and the other parts are made of high-purity electrofused quartz glass, the cost of reaction tube 1 will also increase.

[0061] In this embodiment of the plasma processing apparatus, by employing a structure in which a reaction tube wall protective plate 110 made of synthetic quartz glass with an OH group concentration of 200 ppm or higher is disposed inside the reaction tube 1, the reaction tube 1 can be made of, for example, high-purity electrofused quartz glass. This allows for the suppression of cost increases associated with the reaction tube 1. Furthermore, the supply time of the reaction tube 1 can be shortened when it needs to be replaced.

[0062] In addition, during maintenance, only the reaction tube wall protection component 100 or the reaction tube wall protection plate 110 needs to be replaced, which can reduce maintenance costs and environmental impact compared to replacing the entire reaction tube 1.

[0063] Furthermore, the shape of the reaction tube wall protection plate 110 is preferably an arc shape cut from a cylindrical shape. This allows the arc-shaped reaction tube wall protection plate 110 to be arranged along the inner wall surface of the reaction tube 1.

[0064] Furthermore, the shape of the reaction tube wall protective plate 110 is not limited to this. It can be as follows: Figures 3-6 As shown, the reaction tube wall protection plate 110 is constructed by combining plate shapes. Specifically, the reaction tube wall protection plate 110 is formed by fusing plate-shaped portion 110b to one end of plate-shaped portion 110a in the width direction and plate-shaped portion 110c to the other end of plate-shaped portion 110a in the width direction. Furthermore, plate-shaped portion 110b is bent relative to plate-shaped portion 110a towards the surface side (towards the center of reaction tube 1), and plate-shaped portion 110c is bent relative to plate-shaped portion 110a towards the surface side (towards the center of reaction tube 1). By arranging multiple plate-shaped portions 110a to 110c in such a bent configuration, the manufacturing cost of the reaction tube wall protection plate 110 can be reduced.

[0065] Furthermore, preferably, the upper end of the reaction tube wall protection plate 110 (reaction tube wall protection member 100) is formed in the height direction to a position higher than the upper end of the electrode 31A (for example, a position of +20 cm). Additionally, the lower end of the reaction tube wall protection plate 110 is formed in the height direction to a position lower than the lower end of the electrode 31A, and is further formed into the base portion 120 for supporting the reaction tube wall protection plate 110. Furthermore, the lower end of the reaction tube wall protection member 100 is formed into the lower flange 1d of the reaction tube 1.

[0066] In addition, such as Figure 3 As shown, the width of the reaction tube wall protective plate 110 is preferably wider than the width of the electrode 31A (for example, +10cm on the left and right sides respectively).

[0067] In addition, the thickness of the reaction tube wall protective plate 110 (plate-shaped portion 110a, plate-shaped portion 110b, plate-shaped portion 110c) is preferably in the range of 3mm to 4mm.

[0068] Additionally, a protrusion 115, formed by welding, is provided on the back side of the reaction tube wall protective plate 110. The height of the protrusion 115 is, for example, 2 mm. The protrusion 115 is preferably made of synthetic quartz glass with an OH group concentration of 200 ppm or more, similar to the reaction tube wall protective plate 110.

[0069] A protrusion 115 is formed near the upper end of the back surface of the reaction tube wall protection plate 110, and is formed at the bends (weld joints) of plate-shaped portions 110a and 110b, and at the bends (weld joints) of plate-shaped portions 110a and 110c. When the reaction tube wall protection member 100 is provided in the reaction tube 1, the protrusion 115 abuts against the inner wall surface of the reaction tube 1, thereby supporting the upper part of the reaction tube wall protection plate 110. Thus, as... Figure 4 As shown, a gap can be formed between the inner wall of the reaction tube 1 and the reaction tube wall protective plate 110.

[0070] The base portion 120 can support the lower end of the reaction tube wall protection plate 110, which is erected on the base portion 120. A fixing shaft 125 extending radially outward is provided on the back side of the base portion 120. The base portion 120 is preferably made of synthetic quartz glass with an OH group concentration of 200 ppm or more, similar to the reaction tube wall protection plate 110. Similarly, the fixing shaft 125 is preferably made of synthetic quartz glass with an OH group concentration of 200 ppm or more, similar to the reaction tube wall protection plate 110. Alternatively, the base portion 120 and / or the fixing shaft 125 may also be made of high-purity electrofused quartz glass, similar to the reaction tube 1.

[0071] When installing the reaction tube wall protection component 100 into the reaction tube 1, the base portion 120 is placed on the lower flange 1d formed at the lower end of the reaction tube 1 and extending inward, and the fixing shaft 125 is inserted into the opening port 1e formed on the side wall of the reaction tube 1. At this time, the protrusion 115 abuts against the inner wall surface of the reaction tube 1. As a result, a gap is formed between the back side of the reaction tube wall protection plate 110 and the wall surface of the reaction tube 1. Then, the fixing shaft 125 is fixed using the lower flange 210, retainer 220, nut 230, and O-ring 240 provided on the outer side of the reaction tube 1. Furthermore, the structure for fixing the reaction tube wall protection component 100 to the opening port 1e can be the same as the structure for fixing the gas supply pipe 20 to the opening port of the reaction tube 1.

[0072] Figure 7 This is a cross-sectional structural diagram showing an example of the configuration of the reaction tube 1 and the reaction tube wall protection component 100.

[0073] like Figure 4 As shown, a protrusion 115 is formed on the outer periphery of the reaction tube wall protective plate 110. Furthermore, the reaction tube wall protective plate 110 is arranged such that the protrusion 115 abuts against the inner wall surface of the reaction tube 1. Thus, as... Figure 7 As shown, there is a gap L between the inner wall surface of the reaction tube 1 and the back surface of the reaction tube wall protective plate 110. C .

[0074] During dry cleaning of the reaction tube 1, cleaning gas is also supplied to the gap, and the inner wall surfaces of the electrode mounting sections 1a and 1b of the reaction tube 1 and the outer wall surface of the reaction tube wall protection plate 110 are also cleaned.

[0075] Furthermore, it is preferable that during plasma treatment of the substrate W, no unwanted discharge (abnormal discharge) occurs between the inner wall surface of the reaction tube 1 and the outer wall surface of the reaction tube wall protective plate 110. The distance L between the inner wall surface of the reaction tube 1 and the back surface of the reaction tube wall protective plate 110 is... C Preferably, it is less than 2mm.

[0076] Figure 8 This is a graph representing an example of a Paschen curve. The horizontal axis is the product of the gas pressure p [Torr] and the distance d [cm] of the discharge space, pd [Torr cm]. The vertical axis is the voltage at which each gas begins to discharge (discharge initiation voltage, spark voltage) V. B [Voltage]. Here, the gases NH3, He, Ne, Ar, H2, and N2 are used as examples for explanation.

[0077] Here, the potential of the reaction tube wall protection component 100 (reaction tube wall protection plate 110) can be considered to be approximately 0V. Furthermore, when the gas pressure p is, for example, 400 mTorr, and the distance d (interval L) of the discharge space is... C When the diameter is 2 mm, pd = 0.08 [Torr cm] (1 × 10⁻⁶) -1 [Torr cm] (below). For example... Figure 8 As shown, at pd = 1 × 10 -1 At [Torr cm], the discharge initiation voltage of NH3 is approximately 4000V. That is, when the gas pressure p is, for example, 400mTorr, and the distance d (interval L) of the discharge space is [Torr cm], the discharge initiation voltage of NH3 is approximately 4000V. C When the diameter is less than 2 mm, the discharge initiation voltage of any of the gases NH3, He, Ne, Ar, H2, and N2 is above 4000V. In this device, it is used when the maximum value of the high-frequency voltage applied to electrodes 31A and 31B is less than 4000V. Therefore, by maintaining a distance L between the inner wall surface of the reaction tube 1 and the back surface of the reaction tube wall protective plate 110... C With a diameter of less than 2mm, abnormal discharge can be prevented on the back side of the protective plate 110 of the reaction tube wall. This prevents damage to the inner wall surface of the reaction tube 1 due to abnormal discharge.

[0078] Furthermore, this invention is not limited to the technical solutions listed in the above embodiments, or combinations thereof, as shown herein. Changes can be made in these aspects without departing from the spirit of the invention, and can be appropriately determined according to its application.

Claims

1. A plasma processing apparatus capable of performing plasma processing on a substrate in a reaction tube, the plasma processing apparatus characterized by comprising: the reaction tube which is cylindrical; a substrate holder capable of being inserted and withdrawn with respect to the reaction tube, which is capable of placing a plurality of substrates in multiple layers; a pair of electrodes disposed on the outside of the reaction tube, which are disposed in opposition across the center of the reaction tube; a high-frequency power source capable of applying high-frequency electric power to one pair or a single side of the electrodes in the pair of electrodes to generate plasma in the reaction tube; and a pair of reaction tube wall protection members disposed between the pair of electrodes, which have a first reaction tube wall protection member disposed between one electrode and the substrate holder, and a second reaction tube wall protection member disposed between the other electrode and the substrate holder, the pair of reaction tube wall protection members being disposed in a manner so as to cover the inner wall surface of the reaction tube which is opposite the outer wall surface for disposing the pair of electrodes.

2. The plasma processing apparatus according to claim 1, characterized in that: the pair of reaction tube wall protection members each have a reaction tube wall protection plate which covers the inner wall surface of the reaction tube which is opposite the outer wall surface for disposing the pair of electrodes, the reaction tube wall protection plate being composed of synthetic quartz glass having an OH group concentration of 200 ppm or more.

3. The plasma processing apparatus according to claim 2, characterized in that: the reaction tube is composed of electrically fused quartz glass.

4. The plasma processing apparatus according to claim 2, characterized in that: the reaction tube wall protection plate has a structure in which a plurality of plate-shaped portions are connected in a curved manner.

5. The plasma processing apparatus according to claim 2, characterized in that: the reaction tube wall protection plate has a circular arc shape.

6. The plasma processing apparatus according to claim 2, characterized in that: a protruding portion which abuts against the inner wall surface of the reaction tube is provided on the back surface side of the reaction tube wall protection plate.

7. The plasma processing apparatus according to claim 6, characterized in that: the interval between the back surface side of the reaction tube wall protection plate and the inner wall surface of the reaction tube is 2 mm or less.

8. The plasma processing apparatus according to claim 2, characterized in that: the width of the reaction tube wall protection plate is wider than the width of the electrode.

9. The plasma processing apparatus according to claim 2, characterized in that: the upper end of the reaction tube wall protection plate is formed at a position higher than the upper end of the electrode, and the lower end of the reaction tube wall protection plate is formed at a position lower than the lower end of the electrode.

10. The plasma processing apparatus according to claim 1, characterized in that: the reaction tube wall protection member has a reaction tube wall protection plate which covers the inner wall surface of the reaction tube which is opposite the outer wall surface for disposing the pair of electrodes, the reaction tube wall protection plate being composed of synthetic quartz glass having an OH group concentration of 200 ppm or more.

11. The plasma processing apparatus according to claim 10, characterized in that: the reaction tube is composed of electrically fused quartz glass.

12. The plasma processing apparatus according to claim 10, characterized in that: the reaction tube wall protection plate has a structure in which a plurality of plate-shaped portions are connected in a curved manner.

13. The plasma processing apparatus according to claim 10, characterized in that: the reaction tube wall protection plate has a circular arc shape.

14. The plasma processing apparatus according to claim 10, characterized in that: a protruding portion which abuts against the inner wall surface of the reaction tube is provided on the back surface side of the reaction tube wall protection plate.

15. The plasma processing apparatus according to claim 14, characterized in that: the interval between the back surface side of the reaction tube wall protection plate and the inner wall surface of the reaction tube is 2 mm or less.

16. The plasma processing apparatus according to claim 10, characterized in that: the width of the reaction tube wall protection plate is wider than the width of the electrode.

17. The plasma processing apparatus according to claim 10, characterized in that: the upper end of the reaction tube wall protection plate is formed at a position higher than the upper end of the electrode, and the lower end of the reaction tube wall protection plate is formed at a position lower than the lower end of the electrode. ​ ​ ​ ​ ​ ​ ​ ​ ​ 10. A reaction tube wall protection member, which is a reaction tube wall protection member disposed in a reaction tube of a plasma processing apparatus capable of performing plasma processing on a substrate in the reaction tube, the plasma processing apparatus comprising: ​ ​ ​ ​ A reaction tube wall protection plate which is made of synthetic quartz glass having an OH group concentration of 200 ppm or more, covers an inner wall surface of an electrode installation portion of the reaction tube for installing the electrode; and A base portion for supporting the reaction tube wall protection plate.

11. The reaction tube wall protection member according to claim 10, wherein: A protruding portion which abuts against the inner wall surface of the reaction tube is provided on the back surface side of the reaction tube wall protection plate.

Images