Plasma processing device

Abstract

To provide a plasma processing device that generates plasma on a substrate to process the substrate.SOLUTION: A plasma processing device includes a processing container, a gas supply tube that supplies a processing gas into the processing container, an exhaust part that exhausts the processing container, a pair of electrodes disposed outside the processing container and disposed opposite to each other about the center of the processing container, a high-frequency power source that applies high-frequency power to the pair of electrodes to generate capacitively coupled plasma in the processing container, an inner tube provided inside the processing container and having an opening penetrating from one electrode to the other electrode, a substrate holder that is inserted into the inner tube and holds a number of substrate in multiple stages, a rotation shaft that supports the substrate holder, a rotation mechanism that rotates the rotation shaft, and a lifting mechanism that lifts the rotation shaft. The substrate holder includes a ring member that holds the substrate and surrounds the outer side of the substrate in a radial direction in plan view.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present disclosure relates to a plasma processing apparatus.

Background Art

[0002] Patent Document 1 discloses a plasma processing apparatus including a processing container, a wafer boat that holds a plurality of wafers and is inserted into and removed from the processing container, and a plasma generation unit provided along the height direction of the processing container, which is formed by recessing a part of the side wall of the processing container outward in a concave shape so that one side is opened and communicated inside the processing container. Radicals generated in the plasma generation unit are discharged from the opening of the plasma generation unit toward the center direction inside the processing container and diffuse, and flow in a laminar state between the wafers.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In one aspect, the present disclosure provides a plasma processing apparatus that generates plasma on a substrate and performs processing on the substrate.

Means for Solving the Problems

[0005] To solve the above problems, according to one aspect, there is provided a plasma processing apparatus including a processing container, a gas supply pipe for supplying a processing gas into the processing container, an exhaust unit for exhausting the inside of the processing container, a pair of electrodes disposed outside the processing container and facing the center of the processing container, a high-frequency power supply for applying high-frequency power to the pair of electrodes to generate capacitively coupled plasma in the processing container, an inner pipe provided in the processing container and having an opening penetrating from one of the electrodes toward the other electrode, a substrate holder inserted into the inner pipe and holding a plurality of substrates in multiple stages, a rotating shaft for supporting the substrate holder, a rotation mechanism for rotating the rotating shaft, and a lifting mechanism for lifting and lowering the rotating shaft. The substrate holder holds the substrate and has a ring member that surrounds the outer side in the radial direction of the substrate in a plan view.

Advantages of the Invention

[0006] According to one aspect, it is possible to provide a plasma processing apparatus that generates plasma on a substrate and performs processing on the substrate.

Brief Description of the Drawings

[0007]

Figure 1

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Figure 3

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Figure 8

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Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same constituent parts, and redundant descriptions may be omitted.

[0009] 〔Plasma Processing Apparatus〕 The plasma processing apparatus (substrate processing apparatus) according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a longitudinal sectional configuration diagram showing an example of the plasma processing apparatus. FIG. 2 is a longitudinal sectional configuration diagram showing an example of the plasma processing apparatus as viewed from arrow A shown in FIG. 1. FIG. 3 is a transverse sectional configuration diagram showing an example of the plasma processing apparatus in the B-B section shown in FIG. 2. The plasma processing apparatus shown in FIGS. 1 to 3 is a batch-type plasma processing apparatus that performs substrate processing (for example, film formation processing, etc.) on a plurality of substrates W.

[0010] The plasma processing apparatus has a cylindrical processing vessel 1 with a ceiling and an open lower end. The entire processing vessel 1 is made of, for example, quartz. A ceiling plate 2 made of quartz is provided near the upper end of the processing vessel 1, and the area below the ceiling plate 2 is sealed. The processing vessel 1 also has an inner tube 200 (see FIG. 3) having an opening 210. The inner tube 200 is made of an insulator (dielectric) such as quartz. The opening 210 penetrates from one electrode 31A to the other electrode 31B. Note that the inner tube 200 is omitted in FIGS. 1 and 2.

[0011] The bottom of the processing vessel 1 and the inner tube 200 are open, and a wafer boat (substrate holder) 3 on which a large number of semiconductor wafers (for example, several to about 100) as substrates to be processed are placed in multiple stages is inserted into the inner tube 200 from the bottom of the processing vessel 1 and the inner tube 200. In this manner, a large number of substrates W are accommodated substantially horizontally in the processing vessel 1 with a space 1c of a distance L W in the vertical direction. The wafer boat 3 is made of, for example, quartz. The wafer boat 3 has four rods 4 (see FIG. 3; two are illustrated in FIGS. 1 and 2), and a plurality of ring members 100 for holding the substrates W. When the substrates W are held by the wafer boat 3, the ring members 100 surround the radially outer side of the substrates W in a plan view. A plurality of ring members 100 are arranged at a predetermined interval in the height direction, and are supported by rods 4. Note that the ring members 100 and the inner tube 200 are omitted in Figs. 1 and 2. The ring members 100 and the inner tube 200 will be described in detail later with reference to Figs. 8 to 14.

[0012] The wafer boat 3 is placed on a table 6 via a heat-retaining tube 5 made of quartz. The table 6 is supported on a rotating shaft 8 that passes through a metal (stainless steel) lid 7 that opens and closes the opening at the bottom of the processing vessel 1.

[0013] A magnetic fluid seal 9 is provided in the through-hole of the rotating shaft 8, which hermetically seals the rotating shaft 8 and supports it rotatably. A seal member 10 for maintaining the airtightness inside the processing container 1 is provided between the peripheral portion of the lid body 7 and the lower end of the processing container 1.

[0014] The rotating shaft 8 is attached to the tip of an arm 11 supported by a lifting mechanism (not shown) such as a boat elevator. The wafer boat 3 and the lid body 7 move up and down integrally and are inserted into and removed from the processing container 1. Note that the table 6 may be fixed to the lid body 7 side, and the substrate W may be processed without rotating the wafer boat 3.

[0015] Further, the plasma processing apparatus includes a wafer boat rotation mechanism (not shown) that rotates the wafer boat 3 inside the inner tube 200 by rotating the rotating shaft 8. Further, the plasma processing apparatus includes a wafer boat lifting mechanism (not shown) that moves the wafer boat 3 up and down in the axial direction of the rotating shaft inside the inner tube 200 by moving the rotating shaft 8 in the axial direction with the lid body 7 closing the lower opening of the processing container 1.

[0016] Further, the plasma processing apparatus has a gas supply unit that supplies a predetermined gas such as a processing gas and a purge gas into the processing container 1.

[0017] The gas supply unit has a gas supply pipe 20. The gas supply pipe 20 is formed of, for example, quartz, penetrates the side wall of the processing container 1 inward, bends upward, and extends vertically. A plurality of gas holes 20g are formed at predetermined intervals over the vertical length corresponding to the wafer support range of the wafer boat 3 in the vertical portion of the gas supply pipe 20. Each gas hole 20g discharges gas in the horizontal direction. A processing gas is supplied to the gas supply pipe 20 from a gas supply source (not shown) via a gas pipe. The gas pipe is provided with a flow controller (not shown) and an on-off valve (not shown). Thereby, the processing gas from the gas supply source is supplied into the processing container 1 via the gas pipe and the gas supply pipe 20. The flow controller is configured to be able to control the flow rate of the gas supplied from the gas supply pipe 20 into the processing container 1. The on-off valve is configured to be able to control the supply and stop of the gas supplied from the gas supply pipe 20 into the processing container 1.

[0018] In addition, in FIG. 3, four gas supply pipes 20 are shown, but the number of gas supply pipes 20 is not limited to this. Also, the four gas supply pipes 20 may be configured to supply different gases into the processing container 1, or at least two or more gas supply pipes 20 may be configured to supply the same gas into the processing container 1.

[0019] A pair of electrodes 31A and 31B are provided outside the processing container 1. The pair of electrodes 31A and 31B are each formed of a flat plate and are installed in electrode installation portions 1a and 1b provided outside the processing container 1. Also, the pair of electrodes 31A and 31B are arranged to face each other with respect to the center of the processing container 1 (the center of the substrate W supported by the wafer boat 3). That is, the electrodes 31A and 31B are arranged at positions rotated 180° in the circumferential direction of the processing container 1. Also, the pair of electrodes 31A and 31B are arranged parallel to each other. Note that the electrode installation portions 1a and 1b may be formed integrally with the processing container 1 or may be formed separately.

[0020] The electrodes 31A and 31B are formed of a good conductor such as metal. Further, it is preferable to use a nickel alloy as the material of the electrodes 31A and 31B. By using a nickel alloy as the material of the electrodes 31A and 31B, the influence of metal contamination (diffusion of metal atoms into the processing container 1 formed of quartz) on the processing container 1 can be suppressed as compared with the case of using copper as the material of the electrodes 31A and 31B. Further, the nickel alloy has high heat resistance that can be used in the temperature range in which the plasma processing apparatus can be used (the temperature heated by the heating mechanism 50 described later. For example, the range from room temperature to 900°C). Further, the nickel alloy has oxidation resistance.

[0021] Each of the electrodes 31A and 31B is connected to a high-frequency power supply 33 via an impedance matcher 32. The high-frequency power supply 33 and the impedance matcher 32 constitute a high-frequency control system. The high-frequency control system applies impedance-matched high-frequency power to each of the electrodes 31A and 31B. In FIGS. 1 and 2, although it is illustrated that high-frequency power is supplied from one set of the impedance matcher 32 and the high-frequency power supply 33 to each of the electrodes 31A and 31B, the configuration is not limited to this. The impedance matcher 32 and the high-frequency power supply 33 that supply high-frequency power to the electrode 31A and the impedance matcher 32 and the high-frequency power supply 33 that supply high-frequency power to the electrode 31B may be provided individually.

[0022] The power supply lines of the electrodes 31A and 31B are preferably connected to the center of the electrodes. Thereby, high-frequency power is applied to the center of the electrodes 31A and 31B.

[0023] The frequency of the high-frequency power applied to the electrodes 31A and 31B can be in the range of 1 kHz to 100 MHz. Further, the frequency of the high-frequency power applied to the electrodes 31A and 31B is preferably 40 MHz or less in order to suppress the influence of the wavelength of the voltage standing wave generated on the electrodes on the film formation process (substrate process).

[0024] The inside of the processing container 1 is evacuated by an exhaust device 42 described later and is under reduced pressure (vacuum atmosphere). Further, a processing gas is supplied from a gas supply pipe 20 to the inside of the processing container 1. On the other hand, the outside of the processing container 1 is in an atmospheric atmosphere. The electrodes 31A and 31B are arranged in the space of the atmospheric atmosphere outside the processing container 1.

[0025] By applying high-frequency power from each high-frequency power supply 33 to each of the electrodes 31A and 31B, an electric field is formed in the processing container 1, and capacitively coupled plasma (CCP) is generated in the processing container 1.

[0026] As shown in FIGS. 1 and 2, the electrodes 31A and 31B are arranged in a range wider than the range in the height direction of a large number of substrates W placed on the wafer boat 3 in the height direction. In other words, the width L in the height direction of the electrodes 31A and 31B E is wider than the range in the height direction of a large number of substrates W placed on the wafer boat 3. That is, the electrodes 31A and 31B are formed up to a position higher than the uppermost substrate W placed on the wafer boat 3 and down to a position lower than the lowermost substrate W placed on the wafer boat 3.

[0027] As shown in FIG. 3, in the width direction (horizontal direction), the angle θ formed by connecting both ends in the horizontal direction of the electrode 31A and the center of the processing container 1 (the center of the substrate W supported by the wafer boat 3) for the electrode 31A W is within the range of 20° to 60°. Also, the angle θ W is more preferably within the range of 25° to 40°.

[0028] Also, the width of the electrode 31B is equal to the width of the electrode 31A. Also, the pair of electrodes 31A and 31B are arranged to face each other with respect to the center of the processing container 1 (the center of the substrate W supported by the wafer boat 3) and are arranged parallel to each other. Thereby, the electric field direction 300 formed by the two electrodes 31A and 31B is indicated by an arrow in FIG. 3. As shown in FIG. 3, a uniform electric field can be formed on the substrate W.

[0029] Also, in the relationship between the heating mechanism 50 (heating element wire 51) described later and the processing container 1, the electrodes 31A and 31B shield the radiant heat from the heating mechanism 50 (heating element wire 51) to the processing container 1. For this reason, the circumferential length of the processing container 1 shielded by the electrodes 31A and 31B is preferably, for example, 1 / 3 or less of the entire circumference. In other words, the angle θ W is preferably 60° or less. Also, considering the power density etc. of the electrodes 31A and 31B, the angle θ W is preferably within the range of 25° to 60°.

[0030] An exhaust port 12 for evacuating the inside of the processing container 1 is provided in the side wall portion of the processing container 1. An exhaust device (exhaust portion) 42 including a pressure control valve 41 for controlling the pressure inside the processing container 1 and a vacuum pump etc. is connected to the exhaust port 12, and the inside of the processing container 1 is evacuated by the exhaust device 42 via an exhaust pipe.

[0031] Also, in the processing container 1, thermocouples 13 are arranged along the inner wall surface of the processing container 1. A plurality of thermocouples 13 are provided in the height direction. The control unit 70 detects the temperature with the thermocouples 13, and the detected temperature is used for temperature control of the substrate W.

[0032] Also, as shown in FIG. 3, the gas supply pipe 20 and the thermocouples 13 are arranged so as to avoid the electric field (range of the electric field direction 300) formed by the electrodes 31A and 31B.

[0033] A cylindrical heating mechanism 50 is provided around the processing container 1. The heating mechanism 50 has a wound heater element 51. The heater element 51 is arranged so as to surround the processing container 1 and the plurality of electrodes 31A, 31B. Note that the space between the heating mechanism 50 and the processing container 1 is in an air atmosphere, and the electrodes 31A, 31B are arranged in this space. The heating mechanism 50 heats the processing container 1 and the substrate W inside thereof. The heating mechanism 50 controls the temperature of the processing container 1 to a desired temperature. Thereby, the substrate W in the processing container 1 is heated by radiant heat or the like from the wall surface of the processing container 1. Note that the temperature of the processing container 1 heated by the heating mechanism 50 is, for example, within a range from room temperature to 900°C. In the film formation process, the temperature of the processing container 1 is, for example, within a range from 150°C to 600°C. In the film formation process, a range from 200°C to 500°C is preferably used as the temperature of the processing container 1.

[0034] In addition, a shield 60 is provided outside the heating mechanism 50. That is, the shield 60 is arranged so as to surround the processing container 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.

[0035] The plasma processing apparatus also includes a control unit 70. The control unit 70 controls operations of each part of the plasma processing apparatus, for example, supply / stop of each gas by opening / closing of an on-off valve, control of gas flow rate by a flow controller, and exhaust control by an exhaust device 42. The control unit 70 also performs on / off control of high-frequency power by a high-frequency power supply 33 and control of the temperature of the processing container 1 and the substrate W inside thereof by the heating mechanism 50.

[0036] The control unit 70 may be, for example, a computer or the like. A program of a computer that performs operations of each part of the plasma processing apparatus is stored in a storage medium. The storage medium may be, for example, a flexible disk, a compact disk, a hard disk, a flash memory, a DVD, or the like.

[0037] With such a configuration, the plasma processing apparatus can reduce the pressure inside the processing chamber 1 by the exhaust device 42, supply a processing gas into the processing chamber 1 from the gas supply pipe 20, and apply high-frequency power to the electrodes 31A and 31B, thereby generating a capacitively coupled plasma (CCP) inside the processing chamber 1 and performing processing (film formation processing, etching processing, etc.) on the substrate W. Further, the capacitively coupled plasma is also generated in the space 1c between the substrates W. Thereby, the uniformity of radicals and active species generated by the plasma can be improved at the central portion and the outer peripheral portion of the substrate W. Further, at the central portion and the outer peripheral portion of the substrate W, radicals and active species having a sufficient concentration for substrate processing can be generated and supplied to the substrate W.

[0038] FIG. 4 is a graph showing an example of the high-frequency power applied to each of the electrodes 31A and 31B. In the upper graph, the horizontal axis represents time, and the vertical axis represents the voltage applied to the electrode 31A. In the lower graph, the horizontal axis represents time, and the vertical axis represents the voltage applied to the electrode 31B.

[0039] As shown in FIG. 4, the high-frequency power applied from the impedance matcher 32 to the electrodes 31A and 31B has voltages with opposite phases (phase difference of 180°) and the same voltage amplitude and frequency. In other words, the matching circuit of the impedance matcher 32 is determined so that the voltages have opposite phases (phase difference of 180°) and the same voltage amplitude and frequency. Thereby, a high Vpp (maximum amplitude difference of the electrode voltage) can be obtained with low power.

[0040] FIG. 5 is a graph showing an example of the plasma density n p in the region where the substrate is disposed between the electrodes. Here, an example of the plasma density n p (electron density) is shown when argon (Ar) plasma is generated inside the processing chamber 1 by applying 13.56 MHz high-frequency power to the electrodes 31A and 31B with the substrate W not accommodated inside the processing chamber 1. The horizontal axis represents the distance from the center of the substrate W, the plus direction is the direction toward one electrode (31A), and the minus direction is the direction toward the other electrode (31B). The vertical axis represents the density n pis shown. Note that the plasma density n in the vicinity of the electrodes 31A and 31B p is omitted.

[0041] The solid line indicates the plasma density n at pressure 1 p is shown. The dashed line indicates the plasma density n at pressure 2, which is different from pressure 1 p is shown. Note that there is a magnitude relationship of "pressure 1 < pressure 2". As shown in FIG. 5, by changing the pressure, the distribution of the plasma density in the radial direction of the substrate W can be changed. In other words, by controlling the pressure, the uniformity of the plasma density n p in the radial direction of the substrate W can be improved.

[0042] Specifically, in the hydrogen plasma, it is preferable that the pressure in the processing vessel 1 is 25 Pa or less, preferably 15 Pa or less. Thereby, the uniformity of the plasma density in the radial direction of the substrate W can be improved.

[0043] Also, the heat insulation cylinder 5 and the wafer boat 3 are rotated by the rotating shaft 8. Thereby, the uniformity of the substrate processing (plasma processing) in the circumferential direction of the substrate W can be improved.

[0044] The plurality of substrates W in the processing vessel 1 are held with a space in the height direction by the wafer boat 3. Further, by applying high-frequency power to the electrodes 31A and 31B, a capacitively coupled plasma is generated in the processing vessel 1. That is, plasma is generated in the space between the substrates W. Here, the interval L W between the substrates W is preferably 10 mm or more. Thereby, the in-plane uniformity of the plasma generated in the space between the substrates W can be improved. Also, considering the productivity of the substrate processing by the plasma processing apparatus and the size of the processing vessel 1, the substrate interval is preferably in the range of 15 mm to 40 mm.

[0045] In addition, when generating plasma using a gas containing hydrogen (H) such as hydrogen or ammonia as the processing gas, it is preferable to use synthetic quartz glass with an OH group concentration of 200 ppm or more at least for the materials of the electrode installation parts 1a and 1b.

[0046] Here, due to ions and active species containing hydrogen generated in the plasma of the gas containing hydrogen (H), the inner wall of the processing vessel 1 in the electrode installation parts 1a and 1b is sputtered and etched, and is altered to a silicon-rich surface. At the boundary between the altered inner wall part (electrode installation parts 1a and 1b) and other unaltered inner wall parts, a large stress is generated, and there is a risk that the processing vessel 1 may be damaged. On the other hand, by using synthetic quartz glass with an OH group concentration of 200 ppm or more at least for the electrode installation parts 1a and 1b, sputtering and etching can be suppressed, alteration to a silicon-rich surface can be suppressed, and damage to the processing vessel 1 due to stress can be suppressed.

[0047] In addition, since the inner wall of the processing vessel 1 of the electrode installation parts 1a and 1b is sputtered and etched by plasma, by using synthetic quartz glass with an OH group concentration of 200 ppm or more for the inner wall of the processing vessel 1 or the entire processing vessel 1 in the electrode installation parts 1a and 1b, the metal contamination level derived from quartz can be relatively reduced compared with the case of using fused quartz glass made from natural quartz as the raw material.

[0048] Here, in the case of a relatively high pressure such as "Pressure 2" in FIG. 5 or depending on the type of gas used, the plasma density increases from the vicinity of the outer periphery of the substrate W to the inner wall of the processing vessel 1 where the electrode installation parts 1a and 1b are provided compared with the central part of the substrate W. In such a case, the film thickness uniformity of the thin film formed on the substrate W by plasma processing may deteriorate. In addition, the film quality (fine structure, refractive index, etching rate, etc. of the film) may also become non-uniform.

[0049] The plasma processing apparatus using the wafer boat 3C according to the reference example will be described with reference to FIGS. 6 and 7.

[0050] FIG. 6 is a graph showing an example of the ion current density n in the radial direction of the substrate in the plasma processing apparatus using the wafer boat 3C according to the reference example. i In FIG. 6, the horizontal axis represents the distance R [mm] in the direction from the center of the substrate W toward the electrode installation part 1a (or the electrode installation part 1b). In this example, the radius of the substrate W is 150 [mm]. The vertical axis represents the ion current density n i incident from the plasma onto the substrate W. FIG. 7 is a diagram showing the region P with a high plasma density in the plasma processing apparatus using the wafer boat 3C according to the reference example.

[0051] In the plasma processing apparatus according to the reference example, the inner tube 200 (see FIG. 3) is not provided in the processing container 1, and the wafer boat 3C is inserted into the processing container 1. The wafer boat 3C according to the reference example includes a plurality (four in the example of FIG. 7) of rods 4C as shown in FIG. 7, and the outer peripheral portion of the substrate W is inserted into the groove portions (not shown) provided in the rods 4C, so that the groove portions (not shown) of the rods 4C hold the substrate W. In other words, there is a space between the outer peripheral end of the substrate W and the inner wall of the processing container 1.

[0052] In the wafer boat 3C according to the reference example, an example of the measurement result of the ion current density n i incident from the plasma onto the substrate W is shown in the graph of FIG. 6. As approaching from the substrate center to the substrate outer peripheral end, the ion current density n i gradually increases (see the black arrow).

[0053] In FIG. 7, the region P with a high plasma density is indicated by a broken line. The region P with a high plasma density is formed in the region from near the substrate outer peripheral end to the inner walls of the electrode installation parts 1a and 1b. Note that the region P with a high plasma density is a region where the ion current density n i is high. This region P with a high plasma density (the region where the ion current density n i is high) overlaps with the vicinity of the outer periphery of the substrate W.

[0054] Next, the plasma processing apparatus according to the present embodiment will be described with reference to FIGS. 8 to 14.

[0055] FIG. 8 is an example of a view showing the ring member 100 and the substrate W. FIG. 8(a) is an example of a longitudinal sectional view of the ring member 100 and the substrate W held by the ring member 100. FIG. 8(b) is an example of a plan view of the ring member 100 and the substrate W held by the ring member 100.

[0056] Here, the wafer boat 3 of the plasma processing apparatus according to the present embodiment includes a plurality (four in the example of FIG. 8) of rods 4 and a plurality of ring members 100.

[0057] The ring member 100 is a flat plate member having a circular outer periphery in plan view, and has an annular portion 110 having a circular opening 111 penetrating from the upper surface to the lower surface at the center of the circular flat plate member. Further, the annular portion 110 has a circular concave portion 112 in plan view for holding (accommodating) the substrate W on the upper surface. The radius of the concave portion 112 is formed slightly larger than the radius of the substrate W. The concave portion 112 communicates with the opening 111. Further, the circular flat plate member, the circular opening 111, the circular concave portion 112, and the vertical wall portion 120 described later are formed concentrically in plan view. Further, the depth of the concave portion 112 is substantially equal to, for example, the thickness of the substrate W. Thereby, when the substrate W is placed on the concave portion 112, the height of the upper surface of the substrate W and the upper surface of the annular portion 110 may coincide.

[0058] Further, the ring member 100 has a vertical wall portion 120 erected on the upper surface of the annular portion 110. The vertical wall portion 120 is formed in a cylindrical shape. Note that the annular portion 110 and the vertical wall portion 120 are formed such that the radii of their outer peripheral surfaces are equal and the outer peripheral surfaces coincide (see FIG. 8(a)). Note that the present invention is not limited to this, and the radius of the outer peripheral surface of the vertical wall portion 120 may be smaller than the radius of the outer peripheral surface of the annular portion 110.

[0059] Further, the radius of the inner peripheral surface of the vertical wall portion 120 is larger than the radius of the inner peripheral surface of the ring member 100 (the inner peripheral surface of the opening 111). Further, the radius of the inner peripheral surface of the vertical wall portion 120 is larger than the radius of the circumferential surface of the concave portion 112.

[0060] Further, the ring member 100 (annular portion 110 and vertical wall portion 120) is made of an insulating member (dielectric member). Specifically, the ring member 100 (annular portion 110 and vertical wall portion 120) is preferably made of quartz. Also, the ring member 100 may have the annular portion 110 and the vertical wall portion 120 integrally formed. Further, the annular portion 110 and the vertical wall portion 120 may be formed separately and assembled to form the ring member 100. Also, the ring member 100 is electrically floating.

[0061] Also, the wafer boat 3 has a plurality of ring members 100 in the height direction with a predetermined interval. One substrate W is held for one ring member 100. The plurality of ring members 100 are connected by a plurality of rods 4 extending in the height direction. Also, the plurality of ring members 100 are arranged concentrically.

[0062] The distance X from the outer peripheral end of the substrate W to the outer peripheral end of the ring member 100 is preferably 10 mm or more and 80 mm or less, and more preferably 20 mm or more and 50 mm or less.

[0063] The height Z of the vertical wall portion 120 is preferably 0 mm or more and 10 mm or less. Also, the height Z of the vertical wall portion 120 is lower than the interval L of the substrates W (see FIG. 1). Thereby, a gap for transporting the substrate W is formed between the upper surface of the vertical wall portion 120 in one ring member 100 and the lower surface of the annular portion 110 in another ring member 100 arranged adjacent to the one ring member 100. W FIG. 9 is an example of a view showing the inner tube 200. FIG. 10 is a longitudinal sectional configuration view showing an example of the plasma processing apparatus in a state where the inner tube 200 is installed in the processing container 1. FIG. 11 is an example of a horizontal sectional view showing the positional relationship between the ring member 100 on which the substrate W is installed and the inner tube 200.

[0064] FIG. 18 is an example of a view showing the inner tube 200. FIG. 10 is a longitudinal sectional configuration view showing an example of the plasma processing apparatus in a state where the inner tube 200 is installed in the processing container 1. FIG. 11 is an example of a horizontal sectional view showing the positional relationship between the ring member 100 on which the substrate W is installed and the inner tube 200.

[0065] The inner tube 200 has a cylindrical shape and is open at the bottom. The wafer boat 3 can be inserted through the opening at the bottom of the inner tube 200. The upper part of the inner tube 200 may be open or closed. The inner tube 200 is made of an insulating member (dielectric member). Specifically, the inner tube 200 is preferably made of quartz.

[0066] The inner tube 200 has a horizontally elongated opening 210 in the direction in which the electrodes 31A and 31B are provided. A plurality of openings 210 are provided in the height direction (axial direction of the inner tube 200). Further, ribs 220 are provided between the openings 210 adjacent in the height direction. That is, on the side wall of the inner tube 200, the openings 210 and the ribs 220 are alternately provided in the height direction. Here, the number of the ribs 220 may be the same as the number of the ring members 100 provided on the wafer boat 3. Also, the pitch at which the ribs 220 are provided on the inner tube 200 (the center-to-center distance between adjacent ribs 220 in the height direction) is equal to the pitch at which the ring members 100 are provided on the wafer boat 3 (the center-to-center distance between adjacent ring members 100 in the height direction).

[0067] As shown in FIG. 11, the opening 210 is provided in the direction of one of the electrodes 31A from the center of the rotation axis 8, and the opening 210 is provided in the direction of the other electrode 31B from the center of the rotation axis 8. It is preferably formed such that the width of the opening 210 is wider than the widths of the electrodes 31A and 31B when viewed in the direction from one electrode 31A to the other electrode 31B.

[0068] Next, a method for adjusting the opening height will be described with reference to FIG. 12. FIG. 12 is an example of a diagram for explaining the opening height adjustment method.

[0069] The wafer boat 3 is connected to the rotating shaft 8. This rotating shaft 8 rotates in the rotation direction 410 by a wafer boat rotation mechanism (not shown). By rotating the rotating shaft 8, the wafer boat 3 rotates within the inner tube 200. Further, this rotating shaft 8 moves in the axial direction (vertical direction) 420 by a wafer boat lifting mechanism (not shown). The wafer boat lifting mechanism raises and lowers the rotating shaft 8 with a resolution of, for example, 0.2 mm. By raising and lowering the rotating shaft 8, the wafer boat 3 rises and falls within the inner tube 200.

[0070] FIG. 12(a) shows a state in which the wafer boat 3 is disposed at the reference position (home position) of the wafer boat 3. The reference position (home position) of the wafer boat 3 is a position where the upper surface position of the rib 220 and the upper surface position of the vertical wall portion 120 coincide in the height direction.

[0071] Here, let the thickness of the annular shape portion 110 be CD, the height of the vertical wall portion 120 be Z, the height of the rib 220 be RH, and the opening height of the opening as viewed from the outside of the inner tube 200 be WH. As shown in FIG. 12(a), the height RH of the rib 220 may be the same as the height (CD + Z) of the ring member 100. Further, at the reference position (home position) of the wafer boat 3, the height RH of the rib 220 may protrude up to 4 mm below the height (CD + Z) of the ring member 100. That is, RH = CD + Z + α (where α is 0 [mm] ≦ α ≦ 4 [mm]) may be used.

[0072] Also, the clearance between the inner wall of the inner tube 200 and the wafer boat 3 is preferably about 5 mm.

[0073] In the state shown in FIG. 12(a), the opening height W of the opening as viewed from the outside of the inner tube 200 H is the height from the upper surface position of the rib 220 (the upper surface position of the vertical wall portion 120) to the lower surface position of the rib 220 adjacent in the height direction through the opening 210.

[0074] FIG. 12(b) shows a state in which the wafer boat 3 is disposed at a position moved downward by 421 from the reference position (home position) of the wafer boat 3. In this state, the upper surface position of the vertical wall portion 120 is lower than the upper surface position of the rib 220 and higher than the lower surface position of the rib 220. Also, the lower surface position of the ring member 100 is lower than the lower surface position of the rib 220.

[0075] In the state shown in FIG. 12(b), the opening height W of the opening as viewed from the outside of the inner tube 200 H is the height from the upper surface position of the rib 220 to the lower surface position of the ring member 100. Thus, by lowering the wafer boat 3 by a wafer boat elevating mechanism (not shown), the opening height W H can be reduced. Also, as viewed from the electrodes 31A, 31B, the apparent height of the vertical wall portion 120 is C H (C H > Z) can be set. Note that the apparent height C of the vertical wall portion 120 H is the height at which the lower surface of the rib 220 does not exceed the upper surface of the vertical wall portion 120, and specifically, C H < Z + R H is obtained.

[0076] Here, the rib 220 of the inner tube 200 and the vertical wall portion 120 of the ring member 100 are electrically floating, and an ion sheath is generated on their surfaces by plasma. Then, the rib 220 and the vertical wall portion 120 on which the ion sheath is generated shield the electric field generated between the electrodes 31A, 31B.

[0077] The control unit 70 controls the wafer boat elevating mechanism to move the wafer boat 3 to the reference position (see FIG. 12(a)). Then, the wafer boat 3 is moved downward to a position where the plasma density on the substrate W becomes a desired uniformity (see FIG. 12(b)). Thereby, the opening height W H as viewed from the electrodes 31A, 31B is adjusted, the plasma density on the substrate W is adjusted, and the ion current density n i incident from the plasma onto the substrate W is adjusted.

[0078] FIG. 13 is a graph showing an example of the ion current density in the radial direction of the substrate in a plasma processing apparatus using the wafer boat 3 according to the reference example and the present embodiment. In FIG. 13, the horizontal axis represents the distance R [mm] in the direction from the center of the substrate W toward the electrode installation portion 1a (or the electrode installation portion 1b). In this example, the radius of the substrate W is 150 [mm]. The vertical axis represents the ion current density n incident on the substrate W from the plasma i is. FIG. 14 is a diagram showing a region P with a high plasma density in a plasma processing apparatus using the wafer boat 3 according to the present embodiment.

[0079] Here, in FIG. 13, "A" is the result of the ion current density in the wafer boat 3C according to the reference example (that is, the distance X = 0 [mm], the height of the apparent vertical wall portion 120 = 0 [mm]). "B" is the result of the ion current density at the reference position (that is, the distance X = X1 [mm], the height of the apparent vertical wall portion 120 = Z [mm]) in the wafer boat 3 according to the present embodiment. "C" is the result of the ion current density at the lowered position (that is, the distance X = X1 [mm], the height Z = C H [mm].) in the wafer boat 3 according to the present embodiment.

[0080] As shown by comparing "A" and "B", by providing the ring member 100 and the inner tube 200, the reduction amount of the ion current density n near the outer periphery of the substrate i can be increased.

[0081] As shown by comparing "B" and "C", by adjusting the height of the apparent vertical wall portion 120, the uniformity of the plasma density can be controlled, and the uniformity of the ion current density n i can be controlled.

[0082] As described above, by providing the ring member 100 and the inner tube 200, there is an effect of reducing the ion current density (plasma density) near the outer periphery of the substrate and improving the uniformity of the in-plane distribution of the plasma density on the substrate surface. Further, by raising and lowering the wafer boat 3, the uniformity of the in-plane distribution of the plasma density on the substrate surface can be improved.

[0083] In FIG. 14, a region P with a high plasma density in the wafer boat 3 is indicated by a dashed line. When compared with the case where the ring member 100 and the inner tube 200 are not used (see FIG. 7), in the case where the ring member 100 and the inner tube 200 are used (see FIG. 14), the region P with a high plasma density decreases toward the sides of the electrodes 31A and 31B. Also, the region where the region P with a high plasma density overlaps with the substrate W decreases.

[0084] Further, by using the ring member 100 having the vertical wall portion 120, the diameter of the ring member 100 can be reduced. Thereby, the diameter of the processing container 1 can also be reduced, and the plasma processing apparatus can be miniaturized.

[0085] Note that the configurations and the like described in the above embodiments are not limited to the configurations shown here, such as combinations with other elements. Regarding these points, it is possible to make changes without departing from the spirit of the present invention, and it can be appropriately determined according to the application form.

Description of Reference Numerals

[0086] W Substrate 1 Processing container 2 Ceiling plate 3 Wafer boat (substrate holder) 4 Rod 5 Heat-insulating cylinder 6 Table 7 Lid 8 Rotation shaft 9 Magnetic fluid seal 10 Seal member 11 Arm 12 Exhaust port 20 Gas supply pipe 24g Gas hole 31, 31A, 31B Electrodes 32 Impedance matcher 33 High-frequency power source 50 Heating mechanism 51 Heater element wire 60 Shield 70 Control unit 100 Ring member 110 Annular shape part 111 Opening 112 Recessed part 120 Vertical wall part 200 Inner tube 210 Opening 220 Rib

Claims

1. A processing vessel; a gas supply pipe for supplying a processing gas into the processing vessel; an exhaust unit that exhausts the inside of the processing vessel; A pair of electrodes disposed outside the processing vessel and facing each other with respect to a center of the processing vessel; a high frequency power source that applies high frequency power to the pair of electrodes to generate capacitively coupled plasma in the processing chamber; an inner tube provided in the processing vessel and having an opening extending from one of the electrodes to the other of the electrodes; a substrate holder that is inserted into the inner tube and holds a number of substrates in multiple stages; A rotating shaft supporting the substrate holder; A rotation mechanism that rotates the rotation shaft; a lifting mechanism for lifting the rotation shaft, The substrate holder includes: a ring member that holds the substrate and surrounds the substrate from a radially outer side in a plan view; Plasma processing equipment.

2. The ring member is A ring-shaped portion for holding the substrate; A vertical wall portion provided on the upper surface of the annular portion. The plasma processing apparatus according to claim 1 .

3. The inner tube and the ring member are made of insulating materials. The plasma processing apparatus according to claim 2 .

4. When viewed in a direction from one of the electrodes toward the other of the electrodes, the width of the opening is wider than the width of the electrodes. The plasma processing apparatus according to claim 1 .

5. The opening and the ring member are arranged in a plurality of positions in the height direction. The plasma processing apparatus according to claim 1 .

6. The inner tube is A plurality of the openings and a plurality of ribs provided between the openings adjacent to each other in the height direction are alternately provided, The pitch at which the ribs are provided is equal to the pitch at which the ring members are provided. The plasma processing apparatus according to claim 5 .

7. The height of the rib is equal to or greater than the height of the ring member; The plasma processing apparatus according to claim 6 .

8. A control unit is further provided. The control unit is controlling the lifting mechanism to control the density of plasma formed on the surface of the substrate; The plasma processing apparatus according to claim 1 .

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