Plasma processing apparatus and matching device

Abstract

To provide a plasma processing apparatus and a matching device that can shorten the time required to adjust the matching device.SOLUTION: A plasma processing apparatus includes a high-frequency power supply, a pair of plasma electrodes, and a matching device. The matching device includes: a first load line connected to a high-frequency power supply line, a ground line, and one of the plasma electrodes; a second load line connected to the other plasma electrode; an impedance matching circuit connected to the high-frequency power supply line, the first load line, the second load line, and the ground line, and having a first reactance element; a high-frequency sensor provided on the high-frequency power supply line; and a matching device control unit that receives a detection value from the high-frequency sensor and controls the first reactance element. The first reactance element includes: a first variable capacitor whose capacitance can be continuously varied; and a second variable capacitor connected in parallel with the first variable capacitor and capable of switching between a first state in which the capacitance is a first capacitance and a second state in which the capacitance is a second capacitance.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a plasma processing apparatus and a matching box. [Background technology]

[0002] Patent Document 1 describes a plasma processing apparatus including a chamber, a substrate support table provided in the chamber for supporting a substrate, a first electrode provided inside the substrate support table, a matching box connected to the first electrode, a high-frequency power supply connected to the matching box, and a control unit, wherein the matching box has a lower circuit configured by connecting in parallel a plurality of lower series circuits each consisting of a capacitor and a switching element, and an upper circuit configured by connecting in parallel a plurality of upper series circuits each consisting of a capacitor and a switching element, and the control unit sets the switching elements of the lower series circuit or the upper series circuit to an on state or an off state, The plasma processing apparatus is disclosed, in which the matching box is configured to control the matching box to set one of the lower circuit or the upper circuit, the control unit is configured to control the matching box to wait until an amount of change in impedance seen from the matching box to the chamber side, which changes depending on the setting of the lower circuit or the upper circuit, stabilizes, and the control unit is configured to set the switching element of the lower series circuit or the upper series circuit to an on state or an off state, and to control the matching box to set the other circuit of the lower circuit or the upper circuit, which is different from the one circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-78495 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a plasma processing apparatus and a matching box that reduce the adjustment time of the matching box. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect, a plasma processing apparatus includes a gas supply unit that supplies a processing gas, a high frequency power supply, a pair of plasma electrodes, and a matching box arranged between the pair of plasma electrodes and the high frequency power supply, wherein the matching box includes a high frequency power supply line to which high frequency power is supplied from the high frequency power supply, a ground line that is grounded, a first load line that is connected to one of the plasma electrodes, a second load line that is connected to the other of the plasma electrodes, and an impedance converter that is connected to the high frequency power supply line, the first load line, the second load line, and the ground line and has a first reactance element. a matching circuit; a high-frequency sensor provided on the high-frequency power supply line for detecting the high-frequency power; and a matching circuit control unit that receives the detection value of the high-frequency sensor and controls the first reactance element, wherein the first reactance element comprises a first variable capacitor whose capacitance can be continuously varied, and a second variable capacitor connected in parallel with the first variable capacitor and capable of switching between a first state in which the capacitance is the first capacitance and a second state in which the capacitance is the second capacitance. [Effects of the Invention]

[0006] According to one aspect, it is possible to provide a plasma processing apparatus and a matching box that reduce the time required to adjust the matching box. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a substrate processing apparatus. [Figure 2] 10 is an example of a flowchart illustrating the operation of the substrate processing apparatus. [Figure 3] FIG. 2 is a circuit diagram showing an example of a circuit for supplying high-frequency power to a plasma electrode. [Figure 4]FIG. 2 is an example of a cross-sectional view of a first variable capacitor. [Figure 5] FIG. 2 is an example of a cross-sectional view of a first variable capacitor. [Figure 6] FIG. 10 is an example of a cross-sectional view of a second variable capacitor. [Figure 7] FIG. 10 is an example of a cross-sectional view of a second variable capacitor. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] [Substrate Processing Apparatus] An example of a substrate processing apparatus (plasma processing apparatus) 100 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of the configuration of the substrate processing apparatus 100. In the following description, the substrate processing apparatus 100 will be described as an example of a film formation apparatus that forms a silicon nitride film on a substrate W by an ALD (Atomic Layer Deposition) process using, for example, plasma of a silicon-containing gas and a nitrogen-containing gas.

[0010] The substrate processing apparatus 100 has a cylindrical processing vessel 1 with a ceiling and an open bottom end. The entire processing vessel 1 is made of, for example, quartz. A ceiling plate 2 made of quartz is provided near the top end of the processing vessel 1, and the area below the ceiling plate 2 is sealed. A cylindrical metal manifold 3 is connected to the opening at the bottom end of the processing vessel 1 via a sealing member 4 such as an O-ring.

[0011] The manifold 3 supports the lower end of the processing vessel 1, and a wafer boat 5 (substrate holder) carrying a large number of semiconductor wafers (hereinafter referred to as "substrates W") (e.g., 25 to 150) stacked as substrates is inserted into the processing vessel 1 from below the manifold 3. In this manner, the processing vessel 1 accommodates the large number of substrates W approximately horizontally with spacing between them in the vertical direction. The wafer boat 5 is made of, for example, quartz. The wafer boat 5 has three rods 6 (two are shown in FIG. 1), and the large number of substrates W are supported by grooves (not shown) formed in the rods 6.

[0012] The wafer boat 5 is placed on a table 8 via a heat-retaining cylinder 7 made of quartz. The table 8 is supported on a rotating shaft 10 that passes through a metal (stainless steel) cover 9 that opens and closes the opening at the bottom end of the manifold 3.

[0013] A magnetic fluid seal 11 is provided at the penetration portion of the rotating shaft 10 to airtightly seal and rotatably support the rotating shaft 10. A seal member 12 is provided between the peripheral portion of the lid 9 and the lower end of the manifold 3 to maintain airtightness inside the processing vessel 1.

[0014] The rotation shaft 10 is attached to the tip of an arm 13 supported by a lifting mechanism (not shown), such as a boat elevator, and the wafer boat 5 and the lid 9 are raised and lowered as a unit to be inserted into and removed from the processing vessel 1. Note that the table 8 may be fixed to the lid 9 side so that the substrates W can be processed without rotating the wafer boat 5.

[0015] The substrate processing apparatus 100 also includes a gas supply unit 20 (processing gas supply unit) that supplies predetermined gases such as a processing gas and a purge gas into the processing chamber 1.

[0016] The gas supply unit 20 includes gas supply pipes 21, 22, and 24. The gas supply pipe 21 is made of, for example, quartz, penetrates the side wall of the manifold 3 inward, bends upward, and extends vertically. A plurality of gas holes 21g are formed at predetermined intervals in the vertical portion of the gas supply pipe 21 over a length corresponding to the wafer support range of the wafer boat 5. Each gas hole 21g discharges gas horizontally. The gas supply pipe 22 is made of, for example, quartz, penetrates the side wall of the manifold 3 inward, bends upward, and extends vertically. A plurality of gas holes 22g are formed at predetermined intervals in the vertical portion of the gas supply pipe 22 over a length corresponding to the wafer support range of the wafer boat 5. Each gas hole 22g discharges gas horizontally. The gas supply pipe 24 is made of, for example, quartz, and is a short quartz pipe that penetrates the side wall of the manifold 3.

[0017] A vertical portion of the gas supply pipe 21 (the vertical portion where the gas holes 21g are formed) is installed inside the processing chamber 1. A processing gas (source gas) is supplied to the gas supply pipe 21 from a gas supply source 21a via a gas pipe. A flow rate controller 21b and an on-off valve 21c are installed on the gas pipe. As a result, the processing gas from the gas supply source 21a is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 21. The processing gas (source gas) supplied from the gas supply source 21a is, for example, a precursor gas that adsorbs onto the substrate W, such as a silicon-containing gas. The silicon-containing gas is, for example, DCS (dichlorosilane, SiH2Cl2).

[0018] The gas supply pipe 22 has a vertical portion (the vertical portion where gas holes 22g are formed) disposed in a plasma generation space, which will be described later. A process gas (first process gas) is supplied to the gas supply pipe 22 from a gas supply source 22a via a gas pipe. A flow rate controller 22b and an on-off valve 22c are provided in the gas pipe. As a result, the process gas from the gas supply source 22a is supplied to the plasma generation space via the gas pipe and the gas supply pipe 22, where it is converted into plasma and supplied into the process vessel 1. The process gas (first process gas) supplied from the gas supply source 22a is a reactive gas that reacts with a precursor gas adsorbed on the substrate W to form a film (e.g., a silicon nitride film), and is, for example, a nitrogen-containing gas. The nitrogen-containing gas is, for example, NH3.

[0019] Furthermore, a processing gas (second processing gas) is supplied to the gas supply pipe 22 from a gas supply source 23a via a gas pipe. A flow rate controller 23b and an on-off valve 23c are provided on the gas pipe. The processing gas (second processing gas) supplied from the gas supply source 23a is different from the processing gas (first processing gas) supplied from the gas supply source 22a. As a result, the processing gas from the gas supply source 23a is supplied to the plasma generating space via the gas pipe and the gas supply pipe 22, and is converted into plasma in the plasma generating space and supplied into the processing vessel 1. The processing gas (second processing gas) supplied from the gas supply source 23a is, for example, a modifying gas that modifies the formed film. The modifying gas is, for example, H2.

[0020] Note that the processing gas (raw material gas) supplied from gas supply source 21a, the processing gas (first processing gas, reactive gas) supplied from gas supply source 22a, and the processing gas (second processing gas, modifying gas) supplied from gas supply source 23a are not limited to these.

[0021] A purge gas is supplied to the gas supply pipe 24 from a purge gas supply source (not shown) via a gas pipe. A flow rate controller (not shown) and an on-off valve (not shown) are provided in the gas pipe (not shown). As a result, the purge gas from the purge gas supply source is supplied into the processing vessel 1 via the gas pipe and the gas supply pipe 24. The purge gas supplied from the purge gas supply source is an inert gas such as argon (Ar) or nitrogen (N2). Although the case where the purge gas is supplied into the processing vessel 1 via the gas supply pipe 24 has been described, this is not limiting, and the purge gas may be supplied into the processing vessel 1 via either the gas supply pipe 21 or 22.

[0022] A plasma generation mechanism 30 is formed on a part of the sidewall of the processing chamber 1. The plasma generation mechanism 30 generates plasma from the processing gases (first processing gas and second processing gas) supplied from the gas supply sources 22a and 23a.

[0023] The plasma generation mechanism 30 includes a plasma partition wall 32, a pair of plasma electrodes 33 (one is shown in FIG. 1), a power supply line 34, a matching box 35, a coaxial cable 36, a high-frequency power supply 37, and an insulating protective cover 38.

[0024] The plasma compartment wall 32 is airtightly welded to the outer wall of the processing vessel 1. The plasma compartment wall 32 is made of, for example, quartz. The plasma compartment wall 32 has a concave cross section and covers an opening 31 formed in the side wall of the processing vessel 1. The opening 31 is elongated in the vertical direction so as to cover all of the substrates W supported on the wafer boat 5 in the vertical direction. A gas supply pipe 22 for discharging a processing gas is disposed in an inner space defined by the plasma compartment wall 32 and communicating with the inside of the processing vessel 1, i.e., a plasma generation space. The gas supply pipe 21 for discharging the processing gas is located along the inner wall of the processing vessel 1 outside the plasma generation space, close to the substrates W.

[0025] A pair of plasma electrodes 33 (one is shown in FIG. 1) each have an elongated shape and are arranged facing each other in the vertical direction on the outer surfaces of both sides of the plasma compartment wall 32. Each plasma electrode 33 is held by a holder (not shown) provided on the side of the plasma compartment wall 32, for example. A power supply line 34 is connected to the lower end of each plasma electrode 33.

[0026] The power supply line 34 electrically connects each plasma electrode 33 to the matching box 35. In the illustrated example, one end of the power supply line 34 is connected to the lower end of each plasma electrode 33, and the other end is connected to the matching box 35.

[0027] The matching box 35 has an impedance matching circuit 510 (see FIG. 3, which will be described later), and is a device that performs impedance matching between the high frequency power supply 37 and the substrate processing apparatus 100 (the pair of plasma electrodes 33).

[0028] The coaxial cable 36 electrically connects the matching box 35 and the high frequency power supply 37 .

[0029] A high-frequency power supply 37 is connected to the lower end of each plasma electrode 33 via a coaxial cable 36, a matching box 35, and a power supply line 34, and supplies high-frequency power of, for example, 13.56 MHz to the pair of plasma electrodes 33. This allows the high-frequency power to be supplied into the plasma generation space defined by the plasma partition wall 32. The processing gases (first processing gas and second processing gas) discharged from the gas supply pipe 22 are converted into plasma in the plasma generation space to which the high-frequency power is supplied, and are supplied into the processing vessel 1 through the opening 31.

[0030] The insulating protective cover 38 is attached to the outside of the plasma compartment wall 32 so as to cover the plasma compartment wall 32. A coolant passage (not shown) is provided inside the insulating protective cover 38, and the plasma electrode 33 is cooled by flowing a coolant such as cooled nitrogen (N2) gas through the coolant passage. A shield (not shown) may be provided between the plasma electrode 33 and the insulating protective cover 38 so as to cover the plasma electrode 33. The shield is made of a good conductor such as metal and is grounded.

[0031] An exhaust port 40 (exhaust section) for evacuating the interior of the processing vessel 1 is provided in a sidewall portion of the processing vessel 1 opposite the opening 31. The exhaust port 40 is elongated in the vertical direction to correspond to the wafer boat 5. An exhaust port cover member 41 having a U-shaped cross section is attached to the portion of the processing vessel 1 corresponding to the exhaust port 40. The exhaust port cover member 41 extends upward along the sidewall of the processing vessel 1. An exhaust pipe 42 for evacuating the processing vessel 1 through the exhaust port 40 is connected to the lower part of the exhaust port cover member 41. An exhaust device 44 including a pressure control valve 43, which controls the pressure inside the processing vessel 1, and a vacuum pump, etc., is connected to the exhaust pipe 42. The exhaust device 44 evacuates the interior of the processing vessel 1 through the exhaust pipe 42.

[0032] A cylindrical heating mechanism 50 is provided around the processing vessel 1. The heating mechanism 50 heats the processing vessel 1 and the substrate W therein. The heating mechanism 50 controls the temperature of the processing vessel 1 to a desired temperature. As a result, the substrate W in the processing vessel 1 is heated by radiant heat from the wall surface of the processing vessel 1, etc.

[0033] The substrate processing apparatus 100 also includes a control unit 60. The control unit 60 controls the operation of each unit of the substrate processing apparatus 100, for example, opening and closing the on-off valves 21c and 22c to start and stop the supply of each gas, controlling the gas flow rate by the flow rate controllers 21b and 22b, and controlling exhaust by the exhaust device 44. The control unit 60 also controls the on-off of high frequency power by the high frequency power supply 37, and controls the temperature of the processing chamber 1 and the substrate W therein by the heating mechanism 50. The control unit 60 also controls the matching box 35.

[0034] The control unit 60 may be, for example, a computer. A computer program for controlling the operation of each unit of the substrate processing apparatus 100 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.

[0035] 1 has been described as an example of a configuration in which plasma of a processing gas is generated by the plasma generation mechanism 30 provided on the side of the processing vessel 1 and the activated processing gas is supplied to the substrate W in the processing vessel 1, but the configuration is not limited to this. The substrate processing apparatus 100 may also be configured to generate plasma of a processing gas in the processing vessel 1 and supply the activated processing gas to the substrate W in the processing vessel 1. In this case, the pair of plasma electrodes 33 are disposed opposite each other with the processing vessel 1 in between. In addition, the wall surface of the processing vessel 1 serves as a plasma partition wall that partitions the plasma generation space.

[0036] [Substrate Processing Process of Substrate Processing Apparatus] Next, an example of the operation of the substrate processing apparatus 100 will be described with reference to Fig. 2. Fig. 2 is an example of a flowchart illustrating the operation of the substrate processing apparatus 100.

[0037] In step S101, the substrates W are prepared. Here, the wafer boat 5 on which the substrates W are placed is inserted into the processing chamber 1.

[0038] In step S102, a source gas is supplied. Here, the control unit 60 controls the flow rate controller 21b and the on-off valve 21c to supply the source gas from the gas supply source 21a into the processing chamber 1. As a result, for example, a silicon-containing gas is adsorbed onto the surface of the substrate W.

[0039] In step S103, the matching box 35 is adjusted. Here, the capacitances of the variable capacitors (variable capacitors 511A, 511B, 512A, and 512B described later with reference to FIG. 3) of the matching box 35 are adjusted in advance so as to be suitable capacitances for igniting plasma in step S104 described later.

[0040] In step S104, a first plasma is generated. Here, the control unit 60 controls the flow rate controller 22b and the on-off valve 22c to supply a first process gas from the gas supply source 22a into the plasma generation space. The control unit 60 also controls the high-frequency power supply 37 to supply high-frequency power to the plasma electrode 33. As a result, the first process gas discharged from the gas supply pipe 22 is converted into plasma in the plasma generation space to which the high-frequency power is supplied, and is then supplied into the processing chamber 1 through the opening 31. The matching unit control unit 540 (see FIG. 3, which will be described later) of the matching unit 35 finely adjusts the variable capacitors (variable capacitors 511A and 512A, which will be described later using FIG. 3) of the matching unit 35 so that the power of the reflected wave detected by the high-frequency sensor 520 (see FIG. 3, which will be described later) approaches zero. As a result, for example, the silicon-containing gas adsorbed on the surface of the substrate W is nitrided, and a silicon nitride film is formed on the surface of the substrate W.

[0041] In step S105, the matching box 35 is adjusted. Here, the capacitances of the variable capacitors (variable capacitors 511A, 511B, 512A, and 512B described later with reference to FIG. 3) of the matching box 35 are adjusted in advance so as to be suitable capacitances for igniting plasma in step S106 described later.

[0042] In step S106, a second plasma is generated. Here, the control unit 60 controls the flow rate controller 23b and the on-off valve 23c to supply a second process gas from the gas supply source 23a into the plasma generation space. The control unit 60 also controls the high-frequency power supply 37 to supply high-frequency power to the plasma electrode 33. As a result, the second process gas discharged from the gas supply pipe 22 is converted into plasma in the plasma generation space to which the high-frequency power is supplied, and is then supplied into the processing chamber 1 through the opening 31. The matching unit control unit 540 (see FIG. 3, which will be described later) of the matching unit 35 finely adjusts the variable capacitors (variable capacitors 511A and 512A, which will be described later using FIG. 3) of the matching unit 35 so that the power of the reflected wave detected by the high-frequency sensor 520 (see FIG. 3, which will be described later) approaches zero. As a result, for example, a silicon nitride film formed on the surface of the substrate W is modified by the plasma of the second process gas.

[0043] In step S107, it is determined whether or not the repeated processing is to be ended. If the repeated processing is not to be ended (S107·NO), the processing of the control unit 60 returns to step S102, and the processing of steps S102 to S106 is repeated. If the repeated processing is to be ended (S107·YES), the processing of the control unit 60 is ended.

[0044] As described above, in the substrate processing shown in FIG. 2, one cycle includes a step of supplying a raw material gas (S102), a step of generating plasma of a first processing gas (first plasma) to process the substrate W (S103, S104), and a step of generating plasma of a second processing gas (second plasma) to process the substrate W (S105, S106). This cycle is repeated a predetermined number of times to form a silicon nitride film of a desired thickness on the substrate W.

[0045] The substrate processing is not limited to the substrate processing shown in Fig. 2. The substrate processing includes at least a step of generating plasma of a first processing gas (first plasma) to process the substrate W, and a step of generating plasma of a second processing gas (second plasma) different from the first processing gas to process the substrate W. These steps constitute one cycle, and this cycle may be repeated.

[0046] Here, the capacitance of the variable capacitor of the matching box 35 for reducing the power of the reflected wave to near zero when generating plasma of the first process gas (first plasma) is significantly different from the capacitance of the variable capacitor of the matching box 35 for reducing the power of the reflected wave to near zero when generating plasma of the second process gas (second plasma). Therefore, time (the time of S103 to S105) is required to adjust the matching box 35 before switching the plasma to be generated. Furthermore, an increase in the range of movement and the number of times the variable capacitor can be moved may affect the life of a bellows (bellows 630 shown in FIGS. 4 and 5, which will be described later) provided in the variable capacitor, potentially shortening the periodic replacement cycle of the matching box 35.

[0047] [Matching box] Next, the matching box 35 will be further described with reference to Fig. 3. Fig. 3 is a circuit diagram showing an example of a circuit that supplies high-frequency power to the plasma electrode 33. In Fig. 3, the flow of signals is indicated by dashed arrows.

[0048] The plasma electrode 33 has one plasma electrode 331 and the other plasma electrode 332. The pair of plasma electrodes 331, 332 are arranged facing each other on the outside of the plasma compartment wall 32. Inside the plasma compartment wall 32, a plasma generation space is formed in which plasma 39 is generated.

[0049] The high frequency power supply 37 includes a power supply 410, a high frequency sensor 420, and a power supply control unit 430. The high frequency power supply 37 also includes a high frequency line 451.

[0050] High frequency power is output from the power supply 410 to the high frequency line 451 .

[0051] The power supply 410 includes, for example, a high-frequency oscillator and an amplifier. The high-frequency oscillator is an oscillator that generates a sine wave or a fundamental wave of a predetermined frequency (for example, 13.56 MHz). The amplifier amplifies the power of the sine wave or the fundamental wave output from the high-frequency oscillator with a variably controllable gain or amplification factor. The power supply 410 is controlled by a power supply control unit 430.

[0052] The RF (radio frequency) sensor 420 is provided on the high frequency line 451 and detects the high frequency power output from the high frequency power supply 37. The high frequency sensor 420 also includes a directional coupler on the high frequency line 451. The high frequency sensor 420 detects the power PF1 of a traveling wave propagating in the forward direction on the high frequency line 451, i.e., from the high frequency power supply 37 to the matching box 35. The high frequency sensor 420 also detects the power RF1 of a reflected wave propagating in the reverse direction on the high frequency line 451, i.e., from the matching box 35 to the high frequency power supply 37. The high frequency sensor 420 then outputs the detection result to the power supply control unit 430.

[0053] The power supply control unit 430 controls the power supply 410 in accordance with a control signal from the control unit 60. The power supply control unit 430 also controls the power supply 410 in accordance with the detection result detected by the high-frequency sensor 420. The power supply control unit 430 also outputs the detection result detected by the high-frequency sensor 420 to the control unit 60.

[0054] Coaxial cable 36 connects high-frequency power supply 37 and matching box 35. Specifically, the inner conductor (core) of coaxial cable 36 connects high-frequency line 451 of high-frequency power supply 37 and high-frequency feed line 551 of matching box 35. In addition, the outer conductor (shield) of coaxial cable 36 is grounded.

[0055] Matching box 35 includes an impedance matching circuit 510, a high-frequency sensor 520, a voltage sensor 530, and a matching box control unit 540. Matching box 35 also includes a high-frequency power feed line 551, a ground line 552, a first load line 553, and a second load line 554.

[0056] The high frequency power supply line 551 is connected to the high frequency line 451 of the high frequency power supply 37 via the coaxial cable 36. That is, the high frequency power supply line 551 is a line to which high frequency power is supplied from the high frequency power supply 37.

[0057] The ground line 552 is a line that is grounded.

[0058] The first load line 553 is connected to one plasma electrode 331 via the power supply line 341. The second load line 554 is connected to the other plasma electrode 332 via the power supply line 342.

[0059] The impedance matching circuit 510 has a plurality of reactance elements 511 to 514. The impedance matching circuit 510 is connected to a high-frequency power feed line 551, a ground line 552, a first load line 553, and a second load line 554.

[0060] The first reactance element 511 is arranged between the high-frequency power feed line 551 and the ground line 552. The first reactance element 511 is a variable capacitor whose capacitance is adjustable. The first reactance element 511 has a first variable capacitor 511A and a second variable capacitor 511B. The first variable capacitor 511A and the second variable capacitor 511B are connected in parallel. That is, the capacitance of the first reactance element 511 is the sum (VC1+FVC1) of the capacitance VC1 of the first variable capacitor 511A and the capacitance FVC1 of the second variable capacitor 511B. The first variable capacitor 511A and the second variable capacitor 511B are controlled by the matching circuit control unit 540.

[0061] The first variable capacitor 511A is a capacitor whose capacitance (electrostatic capacity) can be varied continuously (without steps). The first variable capacitor 511A will be described later with reference to FIGS.

[0062] The second variable capacitor 511B is a capacitor that can switch between a first state in which the capacitance (electrostatic capacity) is a first capacitance and a second state in which the capacitance (electrostatic capacity) is a second capacitance. The second variable capacitor 511B will be described later with reference to FIGS. 6 and 7.

[0063] The second reactance element 512 is arranged between the first load line 553 and the second load line 554. The second reactance element 512 is a variable capacitor whose capacitance is adjustable. The second reactance element 512 includes a third variable capacitor 512A and a fourth variable capacitor 512B. The third variable capacitor 512A and the fourth variable capacitor 512B are connected in parallel. That is, the capacitance of the second reactance element 512 is the sum (VC2+FVC2) of the capacitance VC2 of the third variable capacitor 512A and the capacitance FVC2 of the fourth variable capacitor 512B. The third variable capacitor 512A and the fourth variable capacitor 512B are controlled by the matching circuit control unit 540.

[0064] The third variable capacitor 512A is a capacitor whose capacitance (electrostatic capacity) can be varied continuously (without steps). The third variable capacitor 512A will be described later with reference to FIGS.

[0065] The fourth variable capacitor 512B is a capacitor that can switch between a third state in which the capacitance (electrostatic capacity) is a third capacitance and a fourth state in which the capacitance (electrostatic capacity) is a fourth capacitance. The fourth variable capacitor 512B will be described later with reference to FIGS. 6 and 7.

[0066] The third reactance element 513 is arranged between the high-frequency power feed line 551 and the first load line 553. The third reactance element 513 is an inductor (coil) having an inductance L1.

[0067] The fourth reactive element 514 is disposed between the ground line 552 and the second load line 554. The fourth reactive element 514 is an inductor (coil) having an inductance L2.

[0068] The reactance elements 511 to 514 may include at least one of a fixed capacitor (for example, a parasitic capacitance), a fixed inductor (for example, a parasitic inductance), and a fixed resistor (for example, a parasitic resistance).

[0069] The radio frequency (RF (radio frequency)) sensor 520 is provided on the radio frequency power feed line 551 and detects the radio frequency power supplied from the radio frequency power supply 37. The radio frequency sensor 520 also includes a directional coupler on the radio frequency power feed line 551. The radio frequency sensor 520 detects the power PF2 of a traveling wave propagating in the forward direction on the radio frequency power feed line 551, i.e., from the radio frequency power supply 37 to the matching box 35. The radio frequency sensor 520 also detects the power RF2 of a reflected wave propagating in the reverse direction on the radio frequency power feed line 551, i.e., from the matching box 35 to the radio frequency power supply 37. The radio frequency sensor 520 then outputs the detection result to the matching box control unit 540.

[0070] The voltage sensor 530 detects the potential difference between the first load line 553 and the second load line 554, and detects the peak value of this potential difference. Then, the voltage sensor 530 outputs the detection result to the matching circuit control unit 540.

[0071] The matching box control unit 540 controls the first reactance element 511 and the second reactance element 512 of the impedance matching circuit 510 in accordance with a control signal from the control unit 60. Furthermore, the matching box control unit 540 controls the first reactance element 511 and the second reactance element 512 of the impedance matching circuit 510 in accordance with the detection results detected by the high frequency sensor 520 and the voltage sensor 530. Furthermore, the matching box control unit 540 outputs the detection results detected by the high frequency sensor 520 and the voltage sensor 530 to the control unit 60.

[0072] The power supply line 34 includes a power supply line 341 and a power supply line 342. The power supply line 341 connects a first load line 553 of the matching box 35 to one of the plasma electrodes 331. The power supply line 342 connects a second load line 554 of the matching box 35 to the other of the plasma electrodes 332.

[0073] With this configuration, the matching box 35 is configured so that the capacitances (electrostatic capacitances) of the first reactance element 511 and the second reactance element 512 can be controlled by the matching box control section 540.

[0074] Therefore, the matching box control unit 540 controls the capacitances (electrostatic capacity) of the first reactance element 511 and the second reactance element 512 so that the power RF2 of the reflected wave is reduced (approaching zero) based on the detection result of the high-frequency sensor 520. In other words, the matching box control unit 540 controls the capacitances (electrostatic capacity) of the first reactance element 511 and the second reactance element 512 so that the impedance on the load side including the impedance matching circuit 510 becomes a predetermined impedance.

[0075] In addition, based on the detection result of the voltage sensor 530, the matching circuit control unit 540 controls the capacitance (electrostatic capacity) of the first reactance element 511 and the second reactance element 512 so that the peak value of the voltage between the plasma electrodes 331 and 332 becomes a predetermined set value.

[0076] In this way, the matching box 35 shown in FIG. 3 can adjust the peak value of the voltage between the plasma electrodes 331 and 332 as well as achieve impedance matching.

[0077] [First variable capacitor 511A, third variable capacitor 512A] Next, first variable capacitor 511A constituting first reactance element 511 will be described with reference to Fig. 4 and Fig. 5. Fig. 4 and Fig. 5 are examples of cross-sectional views of first variable capacitor 511A.

[0078] The third variable capacitor 512A constituting the second reactance element 512 has a structure similar to that of the first variable capacitor 511A, and therefore a duplicated description will be omitted. Note that the first variable capacitor 511A and the third variable capacitor 512A may have different ranges of variable capacitance (electrostatic capacitance).

[0079] The first variable capacitor 511A has an electrode 601 , an electrode 602 , a support 611 , a rotating shaft 612 , a nut 613 , a sleeve 614 , a bearing 615 , a housing 620 , and a bellows 630 .

[0080] Housing 620 has first housing 621, second housing 622, and insulator 623. Insulator 623 is provided between first housing 621 and second housing 622, and insulates first housing 621 from second housing 622.

[0081] Electrode 601 is one of the electrodes that constitute a capacitor. Electrode 601 is made up of a plurality of cylindrical conductors and is supported by first housing 621 of housing 620.

[0082] Electrode 602 is the other electrode that constitutes the capacitor. Electrode 602 is made up of multiple cylindrical conductors and is supported by support 611. Electrodes 601 and 602 have different cylindrical diameters, and have a diameter that allows electrode 602 to be inserted between adjacent electrodes 601.

[0083] By inserting electrode 602 between adjacent electrodes 601, the area where electrodes 601 and 602 face each other changes. In the example of Fig. 3, the area where electrodes 601 and 602 face each other is area S1. In the example of Fig. 4, the area where electrodes 601 and 602 face each other is area S2.

[0084] The rotating shaft 612 is rotatably supported by a second housing 622 of the housing 620 via a bearing 615. The sleeve 614 is fixed to the second housing 622. The sleeve 614 prevents the nut 613 from rotating around the rotation axis of the rotating shaft 612, and guides the nut 613 from moving in the axial direction of the rotation axis of the rotating shaft 612. The support body 611 is fixed to the nut 613.

[0085] The rotating shaft 612 and the nut 613 constitute a rotary-linear mechanism that converts the rotational motion of the rotating shaft 612 into linear motion of the nut 613. A drive motor (not shown) that rotates the rotating shaft 612 and a rotation sensor (not shown, for example, a potentiometer or encoder) that detects the rotation of the rotating shaft 612 are connected to the rotating shaft 612. Matching box control unit 540 controls the drive motor based on the detection value of the rotation sensor, thereby controlling the capacitance (electrostatic capacity).

[0086] By rotating the rotary shaft 612 in one direction, the nut 613 moves in the extending direction (toward the left on the paper in FIGS. 4 and 5) along the rotation axis of the rotary shaft 612. That is, the support 611 moves in a direction approaching the electrode 601. In other words, the support 611 moves in a direction to insert the electrode 602 between the adjacent electrodes 601. This increases the area where the electrodes 601 and 602 face each other, and the capacitance (electrostatic capacity) increases.

[0087] By rotating the rotary shaft 612 in the other direction opposite to the one direction, the nut 613 moves in the contracting direction (to the right on the paper in FIGS. 4 and 5) along the rotation axis of the rotary shaft 612. That is, the support 611 moves in a direction away from the electrode 601. In other words, the support 611 moves in a direction that pulls the electrode 602 out from between the adjacent electrodes 601. This reduces the area where the electrodes 601 and 602 face each other, and the capacitance (electrostatic capacity) decreases.

[0088] [Second variable capacitor 511B, fourth variable capacitor 512B] Next, the second variable capacitor 511B constituting the first reactance element 511 will be described with reference to Figures 6 to 7. Figures 6 and 7 are examples of cross-sectional views of the second variable capacitor 511B.

[0089] The fourth variable capacitor 512B constituting the second reactance element 512 has a structure similar to that of the second variable capacitor 511B, and therefore a duplicated description will be omitted. The second variable capacitor 511B and the fourth variable capacitor 512B may have different variable capacitance (electrostatic capacitance) ranges.

[0090] Second variable capacitor 511B has electrode 701 , electrode 702 , support 711 , drive shaft 712 , sleeve 713 , magnetic body 714 , electromagnet 715 , elastic body 716 , housing 720 , and bellows 730 .

[0091] Housing 720 has first housing 721, second housing 722, and insulator 723. Insulator 723 is provided between first housing 721 and second housing 722, and insulates first housing 721 from second housing 722.

[0092] Electrode 701 is one of the electrodes that constitute a capacitor. Electrode 701 is made up of a plurality of cylindrical conductors, and is supported by first housing 721 of housing 720.

[0093] Electrode 702 is the other electrode that constitutes the capacitor. Electrode 702 is made up of multiple cylindrical conductors and is supported by support 711. Electrodes 701 and 702 have different cylindrical diameters, and have a diameter that allows electrode 702 to be inserted between adjacent electrodes 701.

[0094] By inserting electrode 702 between adjacent electrodes 701, the area where electrodes 701 and 702 face each other changes. In the example of Fig. 6, the area where electrodes 701 and 702 face each other is area S3. In the example of Fig. 7, the area where electrodes 701 and 702 face each other is area S4.

[0095] Sleeve 713 is fixed to second housing 722. Sleeve 713 prevents drive shaft 712 from rotating around its axis and guides drive shaft 712 from moving in the axial direction of drive shaft 712. Support body 711 is fixed to drive shaft 712. Magnetic body 714 is also fixed to drive shaft 712. Elastic body 716 biases magnetic body 714 in a direction away from electromagnet 715. Matching box control unit 540 controls ON / OFF of power supply to electromagnet 715.

[0096] 6, in a state where no power is supplied to the electromagnet 715 (first state), the magnetic body 714 is urged by the elastic body 716 in a direction away from the electromagnet 715. As a result, the area where the electrodes 701 and 702 face each other becomes an area S3, and the capacitance (electrostatic capacity) increases.

[0097] 7, in a state where power is supplied to the electromagnet 715 (second state), the magnetic body 714 is attracted to the electromagnet 715 against the bias of the elastic body 716. As a result, the area where the electrodes 701 and 702 face each other becomes area S4, and the capacitance (electrostatic capacity) decreases.

[0098] With this configuration, when the first plasma is formed, in step S103, second variable capacitor 511B is set to the first state (the state of either FIG. 6 or FIG. 7), and fourth variable capacitor 512B is set to the third state (the state of either FIG. 6 or FIG. 7). Then, in step S104, matching box control unit 540 fine-tunes first variable capacitor 511A and third variable capacitor 512A so that the power of the reflected wave detected by high-frequency sensor 520 approaches zero.

[0099] Furthermore, in step S105 when the second plasma is formed, second variable capacitor 511B is set to the second state (the other state different from the first state in FIG. 6 or FIG. 7), and fourth variable capacitor 512B is set to the fourth state (the other state different from the third state in FIG. 6 or FIG. 7). Then, in step S106, matching box control unit 540 fine-tunes first variable capacitor 511A and third variable capacitor 512A so that the power of the reflected wave detected by high-frequency sensor 520 approaches zero.

[0100] If first reactance element 511 is configured with only first variable capacitor 511A, the capacitance (electrostatic capacity) will change significantly when switching plasma, requiring a long switching time. Also, the range of motion of bellows 630 will be increased, which may affect the rupture life of bellows 630 and shorten the periodic replacement cycle of matching box 35.

[0101] In contrast, by configuring the first reactance element 511 with a first variable capacitor 511A and a second variable capacitor 511B, the capacitance (electrostatic capacity) can be changed quickly and significantly by switching the power supply state of the electromagnet 715 of the second variable capacitor 511B when switching plasma, thereby shortening the switching time.

[0102] Furthermore, since the range of movement of bellows 630 can be shortened, the life of bellows 630 before rupture can be extended, and the periodic replacement cycle of matching device 35 can be extended.

[0103] Bellows 730 can be designed taking into consideration its rupture life, so that the life of matching box 35 can be extended.

[0104] Furthermore, because high-frequency power supply line 551 is supplied with a large amount of power to generate plasma, a configuration in which capacitors connected by switching may cause wear at the contacts and generate noise when turning on and off. In contrast, second variable capacitor 511B and fourth variable capacitor 512B do not experience wear at the contacts due to switching, and do not generate noise when turning on and off.

[0105] Furthermore, although the first reactance element 511 has been described as including one first reactance element 511 and one second reactance element 512 in parallel, the present invention is not limited to this. The first reactance element 511 may have a configuration including one first reactance element 511 and a plurality of second reactance elements 512 in parallel. This allows the capacitance of the first reactance element 511 to be adjusted in accordance with each plasma state by switching the state of each second variable capacitor 511B, even in substrate processing involving a plurality of plasma states.

[0106] 3 has been described as being applied to a batch-type substrate processing apparatus 100, but the present invention is not limited to this. It may also be applied to a matcher in a single-wafer type substrate processing apparatus.

[0107] The present invention is not limited to the configurations described in the above embodiments, but may be combined with other elements, etc. These aspects can be changed without departing from the spirit of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0108] 1. Processing container 20 Gas supply unit 21, 22, 23 Gas supply pipes 30 Plasma generation mechanism 31 Aperture 32 Plasma Compartment Wall 33,331,332 Plasma electrodes 34,341,342 Power supply lines 35 Matching box 36 Coaxial Cable 37 High frequency power supply 38 Insulation protective cover 39 Plasma 40 exhaust port 50 Heating mechanism 60 Control Unit 100 Substrate processing apparatus (plasma processing apparatus) 410 Power supply 420 High Frequency Sensor 430 Power supply control unit 451 High Frequency Line 510 Impedance Matching Circuit 511~514 Reactance elements 511A, 511B, 512A, 512B variable capacitors 520 High Frequency Sensor 530 Voltage Sensor 540 Matching box control section 551 High frequency power supply line 552 Ground Line 553 First Load Line 554 Second Load Line

Claims

1. a gas supply unit that supplies a processing gas; A high frequency power source; A pair of plasma electrodes; a matching box disposed between the pair of plasma electrodes and the high frequency power supply, The matching device includes: a high-frequency power supply line to which high-frequency power is supplied from the high-frequency power supply; a ground line to be grounded; a first load line connected to one of the plasma electrodes; a second load line connected to the other plasma electrode; an impedance matching circuit connected to the high-frequency power feed line, the first load line, the second load line, and the ground line, the impedance matching circuit having a first reactance element; a high frequency sensor provided on the high frequency power supply line for detecting the high frequency power; a matching circuit control unit that receives a detection value of the high frequency sensor and controls the first reactance element, The first reactance element is a first variable capacitor whose capacitance is continuously variable; a second variable capacitor connected in parallel with the first variable capacitor and switchable between a first state in which its capacitance is a first capacitance and a second state in which its capacitance is a second capacitance; Plasma processing equipment.

2. The first reactance element is disposed between the high-frequency power supply line and the ground line, The plasma processing apparatus according to claim 1 .

3. The impedance matching circuit includes: a second reactive element disposed between the first load line and the second load line; The second reactance element is a third variable capacitor whose capacitance is continuously variable; a fourth variable capacitor connected in parallel with the third variable capacitor and capable of switching between a third state in which its capacitance is a third capacitance and a fourth state in which its capacitance is a fourth capacitance; Equipped with The matching circuit control unit a detection value of the high frequency sensor is input, and the first reactance element and the second reactance element are controlled; The plasma processing apparatus according to claim 2 .

4. a third reactance element disposed between the high-frequency power supply line and the first load line; a fourth reactance element disposed between the second load line and the ground line, the third reactance element and the fourth reactance element are inductors. The plasma processing apparatus according to claim 3 .

5. a voltage sensor for detecting a peak value of a potential difference between the first load line and the second load line; The matching circuit control unit The detection values ​​of the high frequency sensor and the voltage sensor are input, and the first reactance element and the second reactance element are controlled. The plasma processing apparatus according to claim 3 .

6. The matching circuit control unit When a first process gas is supplied from the gas supply unit to generate a first plasma, the second variable capacitor is set to the first state; when a second plasma is generated by supplying a second process gas different from the first process gas from the gas supply unit, the second variable capacitor is set to the second state; 6. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus.

7. A matching box is disposed between a pair of plasma electrodes and a high frequency power supply, a high-frequency power supply line to which high-frequency power is supplied from the high-frequency power supply; a ground line to be grounded; a first load line connected to one of the plasma electrodes; a second load line connected to the other plasma electrode; an impedance matching circuit connected to the high-frequency power feed line, the first load line, the second load line, and the ground line, the impedance matching circuit having a first reactance element; a high frequency sensor provided on the high frequency power supply line for detecting the high frequency power; a matching circuit control unit that receives a detection value of the high frequency sensor and controls the first reactance element, The first reactance element is a first variable capacitor whose capacitance is continuously variable; a second variable capacitor connected in parallel with the first variable capacitor and switchable between a first state in which its capacitance is a first capacitance and a second state in which its capacitance is a second capacitance; Matching box.

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