JP2005340760A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable high uniformity plasma generation by suppressing plasma generation between a cathode electrode and a wall of a treatment vessel. <P>SOLUTION: In a parallel flat plate type plasma processing apparatus equipped with the cathode electrode (for example, an upper electrode) and an anode (for example, a lower electrode), an impedance adjusting section including a capacitance component is prepared between the lower electrode and the treatment vessel, and an impedance value of a route from the upper electrode to which a high-frequency power supply is connected to an earth cabinet of a matching circuit through a plasma, the lower electrode, and the wall of the treatment vessel is made to be smaller than that from the upper electrode to the above-mentioned earth cabinet of the matching circuit through the plasma, and the wall of the treatment vessel. Desirably, the impedance adjusting section is set so that a current value flowing on the above-mentioned route may be 10% or less from a maximum value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus that converts a processing gas into plasma using high-frequency power and performs processing such as etching on a substrate using the plasma.

  In the manufacturing process of a flat panel such as a semiconductor device or a liquid crystal display device, a plasma etching apparatus or a plasma CVD film forming apparatus is used to perform a process such as an etching process or a film forming process on a substrate to be processed such as a semiconductor wafer or a glass substrate. Or the like is used.

  FIG. 17 is a view showing a conventional parallel plate type plasma processing apparatus. In this plasma processing apparatus, an upper electrode 12 that also serves as a gas shower head serving as a gas supply unit is provided in a processing vessel 11 made of, for example, aluminum, and the substrate 10 is mounted so as to face the upper electrode 12. A lower electrode 13 that also serves as a mounting table is provided to face each other. The upper electrode 12 is in a state of being sufficiently electrically floated with respect to the processing container 11 by the insulating material 14, and is connected to a high frequency power source 17 through a matching circuit (matching circuit) 15 and configured as a cathode electrode. .

  The lower electrode 13 is connected to the processing container 11 through a conductive path 18 and is configured as an anode electrode. In this example, the conductive path 18 includes a shaft 18a, a support plate 18b, and a bellows body 18c. The upper side of the processing container 11 is connected to a high-frequency power source 17 via a matching box 16 that is a grounded housing. More specifically, the outside of the coaxial cable that connects the high-frequency power source 17 and the matching box 16 is connected. Grounded by connecting to the layer.

  An equivalent circuit of a high-frequency current conducting path in the plasma processing apparatus of FIG. 17 is expressed as shown in FIG. Since the upper electrode 12 and the lower electrode 13 are capacitively coupled when plasma is generated in the processing chamber 11, the path of the high-frequency current from the high-frequency power source 17 is the matching circuit 15 → the upper electrode 12 → the plasma → the lower part. The electrode 13 → the conductive path 18 → the wall of the processing vessel 11 → the matching box 16 → the ground.

  By the way, among substrates to be processed, glass substrates for flat panels such as liquid crystal displays tend to increase in size, and in the future, for example, large tatami mats will be handled. As the size of the substrate 11 increases, the inductance component of the processing vessel 11 increases, and therefore the coupling between the upper electrode 12 and the lower electrode 13 weakens, and the plasma is generated between the upper electrode 12 and the wall of the processing vessel 11. May occur (described as capacitive coupling in FIG. 18). When such plasma is generated, the plasma in the processing container 11 is biased toward the periphery, and as a result, it becomes impossible to perform processing with high in-plane uniformity on the substrate 10, and the inner wall of the processing container 11. There is a problem that the internal parts are damaged or the wear out easily proceeds.

  On the other hand, Patent Document 1 describes a technique in which an impedance adjustment circuit is provided between the lower electrode and the ground in order to control the plasma diffusion state. This technique adjusts the impedance during film formation and during cleaning. By changing the setting of the circuit, plasma having a shape suitable for each process is obtained, and the above-mentioned problems are not focused on and no solution is described.

JP 11-31685 A: Paragraph 0014

  The present invention has been made under such circumstances, and suppresses the generation of plasma between the cathode electrode and the wall of the processing vessel, and generates a highly uniform plasma to face the substrate. An object of the present invention is to provide a plasma processing apparatus capable of performing plasma processing with high internal uniformity.

The present invention provides a plasma processing apparatus for converting a processing gas into plasma by high-frequency power in a processing container and processing the substrate with the plasma.
A cathode electrode and an anode electrode, which are insulated from the processing container and provided opposite to each other in the processing container;
A high frequency power source having one end connected to the cathode electrode via a matching circuit;
The one end side is connected to the anode electrode, the other end side is connected to the processing container, and includes an impedance adjustment unit including a capacitance component,
A substrate is placed on an electrode located on the lower side of the cathode electrode and the anode electrode,
The impedance adjustment unit has an impedance value from the cathode electrode through the plasma, the anode electrode and the processing container wall to the grounded casing of the matching circuit, and the impedance value from the cathode electrode through the plasma and the processing container wall. It is for adjusting the impedance value so that it may become smaller than the impedance value until it reaches the grounding housing of the matching circuit.

  “The cathode electrode and the anode electrode are insulated from the processing container” means that the cathode electrode and the anode electrode are sufficiently electrically floated with respect to the processing container in a portion excluding the impedance adjustment unit.

Another invention is a plasma processing apparatus for converting a processing gas into plasma by high-frequency power in a processing container and processing the substrate with the plasma.
A cathode electrode and an anode electrode, which are insulated from the processing container and provided opposite to each other in the processing container;
A high frequency power source having one end connected to the cathode electrode via a matching circuit;
The one end side is connected to the anode electrode, the other end side is connected to the processing container, and includes an impedance adjustment unit including a capacitance component,
A substrate is placed on an electrode located on the lower side of the cathode electrode and the anode electrode,
The impedance adjuster is for adjusting the impedance value so that the impedance value from the cathode electrode through the plasma, the anode electrode and the wall of the processing vessel to the grounded casing of the matching circuit is minimized. It is characterized by being. “The impedance value from the cathode electrode to the grounding casing of the matching circuit through the plasma, the anode electrode, and the wall of the processing vessel is minimized” includes the case where the impedance value is almost minimized. Including values within 2%.

Furthermore, the present invention can be applied to an upper and lower two-frequency configuration in which a high-frequency power source is connected to both the upper electrode and the lower electrode. In this case, the present invention is a plasma processing apparatus for converting a processing gas into plasma by high-frequency power in a processing container and processing the substrate with the plasma.
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high-frequency power source of 10 MHz to 30 MHz having one end connected to the upper electrode via a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
A first impedance adjustment unit including one end side connected to the lower electrode and the other end side connected to the processing container, and including a capacitance component;
A second impedance adjusting unit including one end side connected to the upper electrode and the other end side connected to the processing container and including a capacitive component;
A substrate is placed on the lower electrode;
The first impedance adjustment unit has an impedance value at a frequency of the first high-frequency power source from the upper electrode through the plasma, the lower electrode, and the wall of the processing container to the ground casing of the first matching circuit. The impedance value is adjusted to be smaller than the impedance value at the frequency of the first high-frequency power source from the upper electrode through the plasma and the wall of the processing vessel to the grounded casing of the first matching circuit. Is for
The second impedance adjustment unit has an impedance value at a frequency of the second high-frequency power source from the lower electrode to the ground casing of the second matching circuit through the plasma, the upper electrode, and the wall of the processing container. The impedance value is adjusted to be smaller than the impedance value at the frequency of the second high-frequency power source from the lower electrode through the plasma and the wall of the processing container to the ground casing of the second matching circuit. It is for the purpose.

Furthermore, another invention in the configuration of the upper and lower two frequencies is a plasma processing apparatus for converting a processing gas into a plasma with a high frequency power in a processing container and processing the substrate with the plasma.
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high-frequency power source of 10 MHz to 30 MHz having one end connected to the upper electrode via a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
A first impedance adjustment unit including one end side connected to the lower electrode and the other end side connected to the processing container, and including a capacitance component;
A second impedance adjusting unit including one end side connected to the upper electrode and the other end side connected to the processing container and including a capacitive component;
A substrate is placed on the lower electrode;
The first impedance adjustment unit has a minimum impedance value at the frequency of the first high-frequency power source from the upper electrode through the plasma, the lower electrode, and the wall of the processing container to the grounded casing of the first matching circuit. Is to adjust the impedance value so that
The second impedance adjustment unit has an impedance value at a frequency of the second high-frequency power source from the lower electrode through the plasma, the upper electrode, and the wall of the processing container to the ground casing of the second matching circuit. It is for adjusting the impedance value so as to be minimized.

Furthermore, the present invention can also be applied to a lower two-frequency configuration in which the first and second high-frequency power sources are connected to the lower electrode. In this case, the present invention is a plasma processing apparatus for converting a processing gas into plasma by high-frequency power in a processing container and processing the substrate with the plasma.
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high frequency power source of 10 MHz to 30 MHz having one end connected to the lower electrode through a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
The one end side is connected to the upper electrode, the other end side is connected to the processing container, and includes a first impedance adjustment unit and a second impedance adjustment unit including a capacitance component,
A substrate is placed on the lower electrode;
The first impedance adjustment unit has an impedance value at a frequency of the first high-frequency power source from the lower electrode to the ground casing of the first matching circuit through the plasma, the upper electrode, and the wall of the processing container. In order to adjust the impedance value so as to be smaller than the impedance value at the frequency of the first high-frequency power source from the lower electrode through the plasma and the wall of the processing vessel to the grounded casing of the first matching circuit. And
The second impedance adjustment unit has an impedance value at a frequency of the second high-frequency power source from the lower electrode to the ground casing of the second matching circuit via the plasma, the upper electrode, and the wall of the processing container. In order to adjust the impedance value to be smaller than the impedance value at the frequency of the second high-frequency power source from the lower electrode through the plasma and the wall of the processing vessel to the grounded housing of the second matching circuit. It is characterized by that.

Furthermore, another invention in the configuration of the lower two frequencies is a plasma processing apparatus for converting a processing gas into plasma by high-frequency power in a processing container and processing the substrate with the plasma.
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high frequency power source of 10 MHz to 30 MHz having one end connected to the lower electrode through a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
The one end side is connected to the upper electrode, the other end side is connected to the processing container, and includes a first impedance adjustment unit and a second impedance adjustment unit including a capacitance component,
A substrate is placed on the lower electrode;
The first impedance adjuster adjusts the impedance value so that the impedance value from the lower electrode through the plasma, the upper electrode, and the wall of the processing container to the ground casing of the first matching circuit is minimized. To adjust,
The second impedance adjustment unit adjusts the impedance value so that the impedance value from the lower electrode through the plasma, the upper electrode, and the wall of the processing container to the ground casing of the second matching circuit is minimized. It is for adjusting.

  Each impedance adjustment unit adjusts the high frequency impedance value of each frequency to change the high frequency current value of each frequency flowing into the anode electrode so that a value within 10% of the maximum value can be obtained. It is preferable that a value is set. About the site | part which connects the other end side of an impedance adjustment part to a processing container, if an anode electrode is a lower electrode, for example, what is necessary is just to connect to the bottom part of a processing container. If this connection part is brought too close to the cathode electrode, plasma is likely to be generated between the cathode electrode and the connection part, and there is no point in providing an impedance adjustment unit. It is preferable to connect to a part opposite to the electrode (the lower side if the anode electrode is the lower electrode, and the upper side if the anode electrode is the upper electrode).

  The impedance adjustment unit may be configured such that the impedance value can be varied using, for example, a capacitance variable capacitor. For example, a dielectric plate that forms a capacitance component provided between the anode electrode and, for example, the inner surface of the processing container. It may be configured with such as. When the impedance adjustment unit can vary the impedance value, the type of plasma processing and the adjustment value of the impedance adjustment unit (in the invention in which the first and second impedance adjustment units are provided, the adjustment value of the first impedance adjustment unit) And the adjustment value of the second impedance adjustment unit) are stored, the impedance adjustment value corresponding to the selected type of plasma processing is read, and a control signal for adjusting the impedance adjustment unit is output. It is good also as a structure which provides a control part.

  In the present invention, it is preferable that a plurality of impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a portion of the anode electrode that is separated from each other in the lateral direction. In the invention for the configuration of the upper and lower two frequencies, a plurality of first impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a part of the lower electrode that is laterally separated from each other. A plurality of impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a portion of the upper electrode that is separated from each other in the lateral direction. In the invention of the configuration of the lower two frequencies, a plurality of first impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a part of the lower electrode that is laterally separated from each other. A plurality of impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a portion of the lower electrode that is separated from each other in the lateral direction.

As described above, the invention in which a plurality of impedance adjusting portions are provided is suitable for processing, for example, a square substrate having a substrate area of 1 m ² or more, and the total value of high-frequency power used in the apparatus is 10 kW or more. Is particularly suitable.

According to the present invention, when processing a substrate by applying high frequency power between a cathode electrode and an anode electrode to generate a plasma, an anode electrode (an electrode facing an electrode to which a high frequency power source is connected becomes an anode electrode). ) And the processing vessel, an impedance adjustment unit including a capacitive component is provided, and the impedance value from the cathode electrode through the plasma, the anode electrode and the processing vessel wall to the grounding casing of the matching circuit is determined by the cathode. Plasma is generated between the cathode electrode and the wall of the processing vessel because the impedance value is smaller than the impedance value from the electrode through the plasma and the wall of the processing vessel to the grounding casing of the matching circuit. Therefore, it is possible to generate plasma with high uniformity and perform plasma processing with high in-plane uniformity on the substrate.
In addition, if a plurality of impedance adjustment units are used and one end side of each impedance adjustment unit is connected to a part of the anode electrode that is laterally separated from each other, the anode electrode is divided into a plurality in the surface direction of the substrate. Since the impedance can be adjusted for each divided region, the plasma distribution can be finely adjusted as compared with the case where the impedance adjustment is performed at one place, and thus a highly uniform plasma can be obtained. For example, if the substrate is a large substrate with an area of 1 m ² or more, it is difficult to make the plasma highly uniform in the plane. Therefore, if the plasma distribution can be finely adjusted, the uniformity can be improved. In addition, the occurrence of local abnormal discharge can be suppressed. When the total value of the high-frequency power is as large as 10 kW or more, abnormal discharge is likely to occur. Therefore, a configuration using a plurality of impedance adjustment units is extremely effective.

  An embodiment in which the plasma processing apparatus of the present invention is applied to an apparatus for etching a glass substrate for a liquid crystal display will be described. In FIG. 1, reference numeral 2 denotes a rectangular tube-shaped processing vessel made of aluminum having an anodized surface. An upper electrode 3 also serving as a gas shower head, which is a gas supply unit, is provided on the upper portion of the processing container 2, and the upper electrode 3 extends along the opening edge of the opening 30 on the upper surface of the processing container 2. The insulating material 31 provided is in a state of being sufficiently electrically floated with respect to the processing container 2. The gas shower head which is the upper electrode 3 is connected to the processing gas supply unit 33 through the gas supply path 32 and supplies the gas supplied from the gas supply path 32 into the processing container 2 through a number of gas holes 34. Is configured to do.

  The upper electrode 3 is connected to the high frequency power source 4 through a matching circuit 41 and a conductive path 40. Further, a matching box 42 is provided so as to surround the opening 30 in the processing container 2 and include a matching circuit 41 therein. The upper portion of the matching box 42 extends as an outer layer portion 43 that constitutes the coaxial cable 44 together with the conductive path 40, and the outer layer portion 43 is grounded. In this example, the matching box 42 corresponds to the grounding housing of the matching circuit.

  A lower electrode 5 that also serves as a mounting table on which the substrate 10 is placed is provided at the bottom of the processing container 2, and the lower electrode 5 is supported by a support 51 through an insulating material 50. Therefore, the lower electrode 5 is in a state of being sufficiently floated from the processing container 2. A protective tube 52 that extends downward through the opening 20 formed in the bottom wall of the processing vessel 2 is provided at the center of the lower surface of the support 51. The lower surface of the protective tube 52 is supported by a conductive support plate 53 having a diameter larger than that of the protective tube 52 and the inside of the tube is closed. The lower end of the conductive bellows body 54 is fixed to the periphery of the support plate 53, and the upper end of the bellows body 54 is fixed to the opening edge of the opening 20 of the processing container 2. The bellows body 54 hermetically divides the internal space where the protective tube 52 is disposed and the atmosphere side space, and the mounting table 5 can be moved up and down via a support plate 53 by a lifting mechanism (not shown).

  One end of a conductive path 55 provided in the protective tube 51 is connected to the lower electrode 5, and an impedance adjusting unit 6 is interposed in the conductive path 55. The other end side of the conductive path 55 is connected to the bottom of the processing container 2 via a support plate 53 and a bellows body 54. The vicinity of the upper electrode 3 in the processing container 2, for example, the upper surface is grounded via the matching box 42 and the outer layer portion 43 of the coaxial cable 44 as described above. In this example, the upper electrode 3 and the lower electrode 5 correspond to a cathode electrode and an anode electrode, respectively.

  An exhaust passage 21 is connected to the side wall of the processing container 2, and a vacuum exhaust means 22 is connected to the exhaust passage 21. Further, a gate valve 24 for opening and closing the transfer port 23 of the substrate 10 is provided on the side wall of the processing container 2.

  By configuring as described above, the high frequency power source 4 → the matching circuit 41 → the upper electrode 3 → the plasma → the lower electrode 5 → the impedance adjusting unit 6 → the processing container 2 → the matching box 42 → the outer layer part 43 of the coaxial cable 44 → the grounding A high-frequency current flows through the path. However, as described in the background art section, since a high-frequency current may flow from the upper electrode 3 to the wall of the processing vessel 2 via plasma, the processing is performed from the lower electrode 5. The impedance of the path (return path) leading to the upper part of the container 2 is adjusted by the impedance adjusting unit 6.

  FIG. 2 is an equivalent circuit for high-frequency current in the plasma processing apparatus of FIG. Since the processing container 2 can be regarded as an inductance component, it is indicated as an inductor. C1 represents the plasma between the upper electrode 3 and the lower electrode 5 as a capacitive component, and C2 represents the plasma between the upper electrode 3 and the wall of the processing vessel 2 as a capacitive component.

  The aim of this embodiment is to cancel the plasma capacitance (C1) and the inductance (L) of the path from the lower electrode 5 to the upper portion of the processing vessel 2 by the capacitance component (C) of the impedance adjustment unit 6. Thus, the impedance of the path is j (−1 / ωC1 + ωL−1 / ωC), and the impedance of the path including the upper electrode 3 → plasma → the wall of the processing vessel 2 is made smaller. For this reason, the impedance adjustment unit 6 includes a capacitance component. As a form thereof, for example, as shown in FIG. 3, a variable capacitance capacitor 61 is used (a), and a fixed capacitance capacitor 62 and a variable capacitance capacitor 61 are combined ( Various configurations such as b) using a fixed capacitor 62 (c), combining a variable capacitor 61 and an inductor 63 (d), using an inductor 64 capable of varying inductance and a fixed capacitor 62 (e) are adopted. be able to. Even when only the fixed capacitor 62 is used, the impedance value can be adjusted by exchanging with a capacitor having a different capacity.

  In reducing the impedance of the normal path described above, the impedance value of the impedance adjustment unit 6 is variously changed from an experimental example to be described later to obtain a current value flowing through the path, and set so that it becomes the maximum value. In other words, it is ideal to set the impedance of the normal path to a minimum, but in practice it is preferably within 2% of the maximum current value, and at least within 10% of the maximum current value. It is preferable to set to.

  The effect of such an embodiment will be described. First, the gate valve 24 is opened, the substrate 10 is carried into the processing container 2 from a load lock chamber (not shown) by a transfer arm (not shown), and the substrate 10 is lowered by a cooperative operation with a lift pin (not shown) penetrating through the lower electrode 5. It is delivered on the electrode 5. Next, the gate valve 24 is closed, and the processing gas is supplied from the processing gas supply unit 33 to the processing container 2 through the upper electrode 3 and is evacuated by the vacuum evacuation means 22 to maintain the inside of the processing container 2 at a predetermined pressure. . Then, by applying high frequency power of 10 MHz to 30 MHz, for example, 10 kW between the upper electrode 3 and the lower electrode 5 from the high frequency power source 4, the processing gas is excited and plasma is generated. As the processing gas, for example, a gas containing halogen, for example, a gas composed of a halogen compound, oxygen gas, argon gas, or the like is used.

  Due to the generation of plasma, the high-frequency current flows through a normal path in terms of the upper electrode 3 → plasma → lower electrode 5 → impedance adjusting unit 6 → processing vessel 2 → matching box 42 → outer layer part 43 of the coaxial cable 44 → grounding. The impedance value of the path is set to be almost the minimum value, and becomes smaller than the impedance value of the upper electrode 3 → plasma → processing container 2 → matching box 42 → outer layer part 43 of the coaxial cable 44 → grounding path. Therefore, it is difficult for plasma to stand between the upper electrode 3 and the wall of the processing vessel 2. As a result, plasma concentrates between the upper electrode 3 and the lower electrode 5, and the plasma on the substrate 10 has high in-plane uniformity. The surface of the substrate 10 is etched by this plasma, for example, but since the in-plane uniformity of the plasma is high, the in-plane uniformity of the etching rate is high, so that uniform etching can be performed within the surface. Further, damage or consumption of the inner wall and internal parts of the processing container 2 can be suppressed.

  Furthermore, in the present invention, as shown in FIG. 4, appropriate adjustment values in the impedance adjustment unit 6 are stored in the storage unit of the control unit 7 as, for example, a table for each processing type, and when the processing type is selected, The appropriate adjustment value corresponding to the processing may be read from data such as a table, and a control signal may be output from the control unit 7 to a motor that drives an actuator of the impedance adjustment unit 6 such as a trimming mechanism of a variable capacitance capacitor. As a specific example in this case, an example in which the appropriate setting value is determined for each etching process when different etching processes are performed continuously, or for each film forming process when a continuous film forming process is performed. An example of determining the appropriate setting value is given.

  Furthermore, in the present invention, as shown in FIGS. 5A and 5B, the impedance adjusting unit 6 is provided with a plurality of, for example, three impedance adjusting units 6A, 6B, 6C, and these impedance adjusting units 6A, 6B, 6C. It is preferable to connect one end side of each of these to portions PA, PB, and PC that are separated from each other in the lateral direction in the lower electrode 5. In brief explanation, the rectangular substrate 10 is divided into three as shown by a chain line in FIG. 5B, for example, and the impedance between the processing container 2 is set to an appropriate value for each divided region. To do. This appropriate value is a value with which a highly uniform plasma is obtained. For example, by repeating trial and error in advance, appropriate values of the impedance adjusting units 6A, 6B, and 6C are found for each process.

To give a more schematic example, for example, when the plasma is strong in the center, the impedance value between the lower electrode 5 and the processing container 2 in the center is increased by increasing the capacitance value of the impedance adjuster 6B corresponding to the center. And the capacitance values of the impedance adjusting units 6A and 6B corresponding to the peripheral part are reduced, thereby adjusting the plasma strong part to shift from the center to the peripheral side. That is, in such an embodiment, the impedance value of the normal path described above including the impedance value of the parallel connection circuit of the impedance adjustment units 6A, 6B, 6C is the upper electrode 3 → plasma → the wall of the processing vessel 2. It is assumed that the impedance values of the impedance adjusters 6A, 6B, and 6C are set so as to be smaller than the impedance value of the abnormal path, but each impedance value is further adjusted while satisfying the condition. This makes it possible to finely adjust the intensity of the plasma in the surface direction of the substrate 10, and this is a very effective technique for generating a highly uniform plasma when handling a large-sized substrate. As the size of the substrate, the present inventor, for example, in a flat substrate for a flat panel, when the substrate area becomes a large substrate having a surface area of 1 m ² or more, the plasma may be in a highly uniform state in the plane. Since it is difficult, it is understood that if the plasma distribution can be finely adjusted, the uniformity can be improved and the occurrence of local abnormal discharge can be suppressed. In particular, when the total value of the high-frequency power is as large as 10 kW or more, abnormal discharge is likely to occur. Therefore, a configuration in which a plurality of impedance adjustment units is provided is extremely effective.

  As shown in FIG. 5, when providing the impedance adjusting portions 6A, 6B, and 6C, protective tubes 52A to 52C are provided so as to extend from the lower surface of the support portion 51 at positions corresponding to the portions PA, PB, and PC, respectively. In addition, an independent support plate 53 is provided for each of the protective tubes 52A to 52C, and a bellows body 54 is provided between each support plate 53 and the processing container 2 as described above with reference to FIG.

  The division of the impedance adjustment region of the lower electrode 5 is not limited to three divisions. For example, the impedance adjustment unit may be provided for each division region by dividing the impedance adjustment region into two parts in the vertical and horizontal directions and dividing the whole into four parts. .

  Also in such an embodiment, as shown in FIG. 6, the adjustment values of the impedance adjustment units 6A, 6B, and 6C are stored in the storage unit in the control unit 7 according to the type of processing, and selected. It is preferable to set the impedance value in each of the impedance adjustment units 6A, 6B, and 6C according to the processed.

  In addition, the impedance adjustment unit 6 may use a dielectric plate or the like that forms a capacitance component as shown in FIGS. 7A to 7C without using a capacitive element such as a variable capacitance capacitor or a fixed capacitance capacitor. . The example of FIG. 7A is configured such that an impedance adjustment unit made of a plate 8 as a dielectric is provided between the lower electrode 5 and the bottom of the processing container 2 in a replaceable manner. The capacitance value of the dielectric plate 8 is set so as to satisfy the condition of the impedance value of the path as described above.

  The example shown in FIG. 7B corresponds to the example of FIG. 5 using a plurality of impedance adjustment units 6A, 6B, and 6C, and the capacitance of the dielectric plate is square (for example, when viewed in plan). Region) and a peripheral portion (a region of a square ring when viewed in a plane), that is, two types of dielectric plates 8A and 8B are used. In this example, the capacitance is changed by changing the material while keeping the thickness of the dielectric plate the same, but the thickness of the lower electrode 5 is changed, for example, as shown in FIG. May be increased to reduce the thickness of the dielectric plate 8 in the region, whereby the capacitance may be changed between the central portion and the peripheral portion.

  In the above-described embodiment, the high-frequency power source 4 is connected to the upper electrode 3 side. However, the high-frequency power source 4 may be connected to the lower electrode 5 side. In this case, the impedance adjusting unit 6 is connected between the upper electrode 3 and the upper portion of the processing container 2, for example, the upper surface. In this case, even if the impedance adjusting unit 6 is provided between the upper electrode 3 and the side wall of the processing vessel 2, it is included in the scope of the present invention, but it is not preferable to provide the impedance adjusting unit 6 below the upper electrode 3. FIG. 8 shows an example in which three impedance adjusting units 6A to 6C are provided in such a type of apparatus. The installation positions of the three impedance adjustment units 6A to 6C can be set to positions corresponding to, for example, PA to PC shown in FIG. 5, but the number of impedance adjustment units 6 is four even if the number is two. It may be the above. As described above, it is preferable that there are a plurality of impedance adjusting units 6, but one impedance adjusting unit 6 may be used.

  Furthermore, the present invention may be applied to an upper and lower two-frequency type apparatus in which the high frequency power source 4 is provided on the upper electrode 3 side and the high frequency power source 100 is provided on the lower electrode 5 side. FIG. 9 shows an embodiment applied to this type of apparatus. In the configuration of FIG. 5, a conductive path 101 is wired in the lower protective tube 52B, and a matching box 102 is provided on the lower end side of the protective tube 52B. In the matching box 102, a matching circuit 103 connected to the conductive path 101 is provided, and a high frequency power source 100 is further connected to the matching circuit 103. The lower portion of the matching box 102 extends as an outer layer portion 105 constituting the coaxial cable 104 together with the conductive path 106, and the outer layer portion 105 is grounded.

  In this example, the matching circuit 41 and the matching circuit 103 correspond to a first matching circuit and a second matching circuit, respectively. The high frequency power sources 4 and 100 correspond to a first high frequency power source and a second high frequency power source, respectively, and the upper first high frequency power source 4 outputs high frequency power of 10 MHz to 30 MHz, for example, 10 kW, and the lower second high frequency power source. The high frequency power supply 100 outputs a high frequency power of 2 MHz to 6 MHz, for example, 3 kW. The high frequency power from the first high frequency power supply 4 plays a role of activating the processing gas, and the power from the second high frequency power supply 100 plays a role of drawing ions in the plasma toward the substrate 10 side. In this example, the matching boxes 42 and 102 correspond to the grounding housing of the first matching circuit and the grounding housing of the second matching circuit, respectively. Although not shown in FIG. 9, a high-pass filter is interposed between the upper electrode 3 and the matching circuit 41, and a low-pass filter is interposed between the lower electrode 5 and the matching circuit 103. The high frequency component of the other party is not input between 4 and 100. In this case, the lower electrode 5 is an anode electrode when viewed from the first high-frequency power source 4, and the upper electrode 3 is an anode electrode when viewed from the second high-frequency power source 100.

  A plurality of impedance adjusters 9A and 9C are provided between the upper electrode 3 and the matching box 42, and these impedance adjusters 9A and 9C are arranged above the processing vessel 2 via the matching box 42, for example, a ceiling portion. It is connected to the. For convenience of illustration, only two upper impedance adjustment units and lower impedance adjustment units 9A and 9C (6A and 6C) are shown, but three or more each may be provided, or only one. May be. Further, in this example, the matching box 42 corresponds to a grounding housing of the first matching circuit 41 for returning the high-frequency current from the first high-frequency power source 4 to the high-frequency power source 4 from the upper part of the processing container 2. Corresponds to the grounding housing of the second matching circuit 103 for returning the high-frequency current from the second high-frequency power source 100 to the high-frequency power source 100 from the lower part of the processing container 2.

  The lower impedance adjusters 6A and 6C correspond to the first impedance adjuster, and are provided with a filter for allowing only high frequencies corresponding to the high frequency band of the first high frequency power supply 4 to pass therethrough. The upper impedance adjusters 9 </ b> A and 9 </ b> C correspond to a second impedance adjuster, and are provided with a filter for allowing only high frequencies corresponding to the high frequency band of the second high frequency power supply 100 to pass therethrough. That is, the high-frequency current from the first high-frequency power source 4 is expressed as follows: high-frequency power source 4 → matching circuit 41 → upper electrode 3 → plasma → lower electrode 5 → impedance adjusting unit 6A, 6C → processing vessel 2 → matching box 42 → coaxial cable 44 The high frequency current from the second high frequency power supply 100 flows through the outer layer 43 → the ground path, and the high frequency current from the second high frequency power supply 100 → the matching circuit 103 → the lower electrode 5 → the plasma → the upper electrode 3 → the impedance adjusting units 9A and 9C → the processing container 2 → Matching box 102 → Outer layer part 105 of coaxial cable 104 → Flow through grounding path.

  As described above, the first impedance adjusters 6A and 6C are transferred from the upper electrode 3 to the matching box 42 (the ground casing of the first matching circuit) via the plasma, the lower electrode 5 and the wall of the processing vessel 2. The high-frequency impedance value of the first high-frequency power source 4 in the normal path up to the first path in the so-called abnormal path from the upper electrode 3 through the plasma and the wall of the processing vessel 2 to the matching box 42 This is for adjusting the impedance value to be smaller than the high frequency impedance value of the high frequency power source 4. In reducing the impedance value of the normal path, the value of the current flowing through the normal path is obtained from the first high-frequency power supply 4 and is set so as to be the maximum value, that is, the impedance of the normal path is minimized. Ideally, it is set to be within the range of 2% of the maximum value of the current, but is preferably set to be within 10% of the maximum value of the current. The current value of the normal path can be obtained by, for example, an ammeter connected to each of the impedance adjustment units 6A and 6C, and the total value of the current values can be used.

  The second impedance adjusters 9A and 9C have a high-frequency impedance value in the second high-frequency power source 100 from the lower electrode 5 to the matching box 102 through the plasma, the upper electrode 3 and the wall of the processing vessel 2, This is for adjusting the impedance value to be smaller than the high-frequency impedance value in the second high-frequency power source 100 from the lower electrode 5 through the plasma and the wall of the processing vessel 2 to the matching box 102. . In order to reduce the impedance value of the normal path, it is ideal to obtain the current value flowing through the normal path from the second high-frequency power supply 100 and set it to be the maximum value. Is preferably within 2% of the maximum value of the current, and is preferably set to be at least within 10% of the maximum value of the current.

  Further, the present invention may be applied to a lower two-frequency type device in which the first high-frequency power source 4 and the second high-frequency power source 100 are provided on the lower electrode 5 side. FIG. 10 shows an embodiment applied to this type of apparatus, in which a protective tube 45 is connected to the lower side of the lower electrode 5 via an insulating layer 50, and the lower end side of the protective tube 45 is connected to the bottom surface of the processing vessel 2. The matching box 42 is connected to the lower end of the protective tube 45. Two matching circuits 41 and 103 are provided in the matching box 42, and one end sides of these matching circuits 41 and 103 are connected to the lower electrode 5 through conductive paths 46 and 101 arranged in the protective tube 45, respectively. The first high frequency power supply 4 and the second high frequency power supply 100 are connected to the other ends of the matching circuits 41 and 103, respectively. 44 and 104 are the coaxial cables described above. The frequency and power of the high-frequency power from the first high-frequency power source 4 and the second high-frequency power source 100 are the same as those in the embodiment shown in FIG.

  The upper electrode 3 includes one end of a plurality of first impedance adjustment units, in this example, three impedance adjustment units 6A to 6C and a plurality of second impedance adjustment units, in this example, three impedance adjustment units 9A to 9C. The other ends of these impedance adjusters 6A to 6C and 9A to 9C are connected to the upper part of the processing container 2, for example, the ceiling, via the conductive cover body 56 that covers the opening 30 of the processing container 2. Has been. One, two, or four or more of the first impedance adjustment unit and the second impedance adjustment unit may be provided. Also in this example, the first impedance adjusters 6 </ b> A to 6 </ b> C are provided with filters for allowing only high frequencies corresponding to the high frequency band of the first high frequency power supply 4 to pass. The second impedance adjusters 9A to 9C are provided with filters for allowing only high frequencies corresponding to the high frequency band of the second high frequency power supply 100 to pass therethrough.

  In this example, the matching box 42 includes a grounding housing of a first matching circuit for returning a high-frequency current from the first high-frequency power source 4 from the lower part of the processing container 3 to the high-frequency power source 4, and a second high-frequency power source 100. Also serves as a grounding housing of the second matching circuit for returning the high-frequency current from the bottom of the processing vessel 3 to the high-frequency power source 100.

  The high-frequency current from the first high-frequency power source 4 is a route of the high-frequency power source 4 → the matching circuit 41 → the lower electrode 3 → the plasma → the upper electrode 5 → the first impedance adjusting units 6A to 6C → the processing container 2 → the matching box 42. The high-frequency current from the second high-frequency power supply 100 flows from the high-frequency power supply 100 → the matching circuit 103 → the lower electrode 5 → the plasma → the upper electrode 3 → the second impedance adjusting units 9A to 9C → the processing container 2 → the matching box 42. It flows along the route.

  The first impedance adjusters 6A to 6C are configured to adjust the high frequency of the first high frequency power supply 4 in a normal path from the lower electrode 5 to the matching box 42 through the plasma, the upper electrode 3 and the wall of the processing vessel 2. The impedance value so that the impedance value becomes smaller than the high frequency impedance value of the first high frequency power supply 4 in an abnormal path from the lower electrode 5 to the matching box 42 through the plasma and the wall of the processing vessel 2. It is for adjusting. In reducing the impedance value of the normal path, the value of the current flowing through the normal path is obtained from the first high-frequency power supply 4 and is set so as to be the maximum value, that is, the impedance of the normal path is minimized. Ideally, it is set to be within the range of 2% of the maximum value of the current, but is preferably set to be within 10% of the maximum value of the current.

  The second impedance adjusters 9A to 9C are provided with the high frequency of the second high frequency power supply 100 in a normal path from the lower electrode 5 to the matching box 42 through the plasma, the upper electrode 3 and the wall of the processing vessel 2. The impedance value of the first high-frequency power supply 4 in an abnormal path from the lower electrode 5 through the plasma and the wall of the processing vessel 2 to the matching box 42 becomes smaller than the impedance value of the first high-frequency power supply 4. It is for adjusting the value. In reducing the impedance value of the normal path, the value of the current flowing through the normal path from the second high-frequency power supply 100 is obtained and set so as to be the maximum value, that is, the impedance of the normal path is minimized. Ideally, it is set to be within the range of 2% of the maximum value of the current, but is preferably set to be within 10% of the maximum value of the current.

  The impedance adjusting unit in the embodiment shown in FIGS. 8 to 10 may be formed of a dielectric material that forms a capacitive component as shown in FIG. Furthermore, as shown in FIG. 4, data in which the plasma processing type and the adjustment value of the impedance adjustment unit are associated with each other may be created, and the impedance adjustment unit may be automatically adjusted when the plasma type is selected.

  FIG. 11 shows an example of a layout in the case where a plurality of impedance adjusting units are provided. In this example, a total of 5 points including four points P1 to P4 which are four corners (corner portions) of the square substrate 10 and the central portion P5. An impedance adjustment unit is provided in a portion corresponding to the point (on the 5-point projection region).

  In the above description, the distance between the upper electrode 3 and the lower electrode 5, the (interelectrode gap), and the appropriate values of the processing pressure are described. As shown in FIG. 1, FIG. 5, and FIG. In the type of apparatus connected to the electrode 3 side, the gap between the electrodes is preferably 50 mm to 300 mm, and the processing pressure is preferably 13 Pa to 27 Pa (100 mTorr to 200 mTorr). 8 and 10, the inter-electrode gap is preferably 200 mm to 700 mm, and the processing pressure is 0.7 Pa to 13 Pa (5 mTorr to 100 mTorr). ) Is preferred.

Next, experimental examples for confirming the effects of the present invention will be described.
(Experiment 1)
A. Experimental Method Impedance adjustment unit 6 using a parallel plate type plasma processing apparatus as shown in FIG. 5 as a test apparatus, in which the impedance adjustment region in the lower electrode is divided into four (in FIG. 5, three divisions). As shown in FIG. 12, four inductors (6A to 6D) in which an inductor 63 and a variable capacitance capacitor 61 are connected in series are connected in parallel. Note that the capacitance component represented by C0 in FIG. 12 corresponds to the capacitance of the dielectric between the lower electrode and the processing container.

  The impedance adjustment unit is set to various values by changing the position of the variable capacitor trimmer, and the state of the plasma generated in the processing container is visually observed for each set value. The current flowing in the conductive path between the container (current flowing in the lower electrode) was detected and the voltage of the upper electrode was measured. As for the plasma generation conditions, the distance between the upper electrode and the lower electrode is set to 60 mm, a mixed gas of SF6 gas, HCl gas and He gas is used as the plasma generating gas, and the frequency and power of the high frequency power source are 13 and 56 MHz, respectively. 7.5 kw, and the pressure was set to 20 Pa (150 mTorr).

B. Experimental Results FIG. 14 includes the trimmer position of the variable capacitance capacitor, the capacitance of the capacitor, the impedance of the capacitor, the impedance value Z (LC) of the impedance adjustment unit, and C0 between the lower electrode and the processing container. It is explanatory drawing which showed the relationship with the total impedance value, the value of the electric current (lower current) which flows into a lower electrode, the value of the voltage (upper voltage) of an upper electrode, and the visual state of plasma. Regarding the visual state of the plasma, the uniformity of the light emission state is very high (）), the uniformity of the light emission state is generally good (◯), the uniformity of the light emission state is slightly bad (△), and the uniformity of the light emission state is poor. Four evaluations of (x) were used. Further, the values of the lower current and the upper voltage shown in FIG. 13 are shown as graphs in FIGS. 14 and 15, respectively. In FIG. 12, the unit of capacitance value is pF, the unit of impedance and impedance value of the capacitor is Ω, and the unit of current value and voltage value is A and V, respectively.

  As can be seen from this result, the lower current has a maximum value at 79 A, and the plasma state at this time is the best. When the lower current is 78 A, the result is that the plasma state is generally good, and when the lower current is 72 A, the result is that the plasma state is somewhat poor. At 66A or less, the plasma state is extremely bad. Therefore, it is preferable to adjust the impedance value so that the lower current becomes almost the maximum value. In this example, considering the measurement error, the lower current is preferably within 10% of the maximum value, and more preferably within 2%. Here, the fact that the lower current value is substantially maximized means that the upper voltage value is substantially maximized, that is, the impedance value between the lower electrode and the processing container is substantially minimized. In other words, the fact that the lower current value is almost maximized means that the current flowing from the upper electrode through the plasma to the wall of the processing vessel is almost minimized. This means that the discharge between the container and the wall of the container is suppressed, and the uniformity of the plasma is improved.

(Experiment 2)
A. Experimental Method A silicon film formed on the surface of a square substrate of 2000 mm × 2200 mm using a two-frequency parallel plate type plasma processing apparatus provided with high-frequency power supplies 4 and 100 as shown in FIG. Etching was performed. The processing conditions are as follows.
Process gas: SF6 gas, HCl gas and He gas upper side high frequency power supply frequency and power: 13.56 MHz and 20 kW
The frequency of the high frequency power supply on the lower side: 3.2 MHz and 4 kW
Processing pressure: 20 Pa (150 mTorr)
Further, the impedance adjustment unit for high frequency from the high frequency power supply 4 on the upper side and the impedance adjustment unit for high frequency from the high frequency power supply 100 on the lower side are all in a total of four positions corresponding to the four corners and the center of the rectangular substrate. Provided. As each impedance adjusting unit, a variable capacitance capacitor and an inductor connected in series as shown in FIG. And, by an ammeter inserted in series in each impedance adjustment section, at the adjustment point at which the current value flowing through the lower electrode side (the total value of the current values of the ammeter) is minimized, a number of in-plane settings on the substrate surface The average value of the etching rate at the position and the in-plane uniformity of the etching rate were investigated. Further, when the impedance adjusting unit is not provided under the same conditions as the above-described processing conditions, the etching rate average is similarly applied in the case where the power applied to the lower electrode side is zero and the lower side high frequency power source is not provided. The in-plane uniformity of the value and the etching rate was investigated.

B. Experimental results The results are shown in FIG. As can be seen from this result, it is understood that the etching rate is improved by connecting the high frequency power source to the lower electrode as compared with the case where the high frequency power source is connected only to the upper electrode. However, the in-plane uniformity of the etching rate is deteriorated by setting the upper and lower two frequencies in this way, but by adjusting the impedance so that the current value flowing to the lower electrode side is minimized by the impedance adjusting unit, In-plane uniformity is also improved.

It is a vertical side view which shows the outline of the whole structure of the plasma processing apparatus which is embodiment of this invention. It is a circuit diagram which shows the equivalent circuit of said embodiment. It is a block diagram which shows the example of the impedance adjustment part used for said embodiment. It is a block diagram which shows an example of said embodiment. It is a vertical side view which shows the outline of the whole structure of the plasma processing apparatus which is other embodiment of this invention. It is a circuit diagram which shows the equivalent circuit of embodiment of FIG. It is a vertical side view which shows the outline of the whole structure of the plasma processing apparatus which is further another embodiment of this invention. It is a vertical side view which shows the outline of the whole structure of the plasma processing apparatus which is further another embodiment of this invention. It is a vertical side view which shows the outline of the whole structure of other plasma processing apparatuses other than the said embodiment. It is a vertical side view which shows the outline of the whole structure of the plasma processing apparatus which is further another embodiment other than the said embodiment. It is explanatory drawing which showed the installation position of the impedance adjustment part corresponding to the position (point) on a board | substrate. It is a circuit diagram which shows the circuit of the impedance adjustment part used for one experiment for confirming the effect of this invention. It is explanatory drawing which shows the whole data of said 1 experimental result. It is explanatory drawing which shows the relationship between the adjustment position of the impedance adjustment part which is said 1 experimental result, and a high frequency current. It is explanatory drawing which shows the relationship between the adjustment position of the impedance adjustment part which is said one experiment result, and a high frequency voltage. It is a characteristic view which shows the etching rate of the silicon | silicone on the board | substrate which is another experimental result, and the in-plane uniformity of an etching rate. It is a vertical side view which shows the outline of the whole structure of the conventional plasma processing apparatus. It is a circuit diagram which shows the equivalent circuit of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate 2 Processing container 3 Upper electrode 31 Insulating material 32 Gas supply path 4 High frequency power supply 42 Matching box 44 Coaxial cable 5 Lower electrode 51 Conductive path 53 Support plate 6, 6A-6C Impedance adjustment part 7 Control part 8, 8A, 8B Dielectric Body plate 9A, 9B Impedance adjustment part 100 High frequency power supply 102 Matching box 104 Coaxial cable

Claims (27)

In a plasma processing apparatus for converting a processing gas into plasma with high-frequency power in a processing container and processing the substrate with the plasma,
A cathode electrode and an anode electrode, which are insulated from the processing container and provided opposite to each other in the processing container;
A high frequency power source having one end connected to the cathode electrode via a matching circuit;
The one end side is connected to the anode electrode, the other end side is connected to the processing container, and includes an impedance adjustment unit including a capacitance component,
A substrate is placed on an electrode located on the lower side of the cathode electrode and the anode electrode,
The impedance adjustment unit has an impedance value from the cathode electrode through the plasma, the anode electrode and the processing container wall to the grounded casing of the matching circuit, and the impedance value from the cathode electrode through the plasma and the processing container wall. A plasma processing apparatus for adjusting an impedance value to be smaller than an impedance value up to a grounding housing of a matching circuit. In a plasma processing apparatus for converting a processing gas into plasma with high-frequency power in a processing container and processing the substrate with the plasma,
A cathode electrode and an anode electrode, which are insulated from the processing container and provided opposite to each other in the processing container;
A high frequency power source having one end connected to the cathode electrode via a matching circuit;
The one end side is connected to the anode electrode, the other end side is connected to the processing container, and includes an impedance adjustment unit including a capacitance component,
A substrate is placed on an electrode located on the lower side of the cathode electrode and the anode electrode,
The impedance adjuster is for adjusting the impedance value so that the impedance value from the cathode electrode through the plasma, the anode electrode and the wall of the processing vessel to the grounded casing of the matching circuit is minimized. There is provided a plasma processing apparatus.   The impedance adjustment unit is characterized in that the impedance value is set such that a value within 10% of the maximum value is obtained when the current value flowing into the anode electrode is changed by adjusting the impedance value. The plasma processing apparatus according to claim 1.   The plasma processing apparatus according to claim 1, wherein the impedance adjustment unit is configured to be able to vary an impedance value.   Data in which the type of plasma processing and the adjustment value of the impedance adjustment unit are associated with each other is stored, and the control signal for adjusting the impedance adjustment unit is output by reading the impedance adjustment value according to the selected type of plasma processing The plasma processing apparatus according to claim 1, further comprising a control unit.   The plasma processing apparatus according to claim 1, wherein the impedance adjusting unit is a dielectric that forms a capacitive component provided between the anode electrode and the processing container.   3. The plasma processing apparatus according to claim 1, wherein a plurality of impedance adjusting units are used, and one end side of each impedance adjusting unit is connected to a portion of the anode electrode that is laterally separated from each other. In a plasma processing apparatus for converting a processing gas into plasma with high-frequency power in a processing container and processing the substrate with the plasma,
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high-frequency power source of 10 MHz to 30 MHz having one end connected to the upper electrode via a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
A first impedance adjustment unit including one end side connected to the lower electrode and the other end side connected to the processing container, and including a capacitance component;
A second impedance adjusting unit including one end side connected to the upper electrode and the other end side connected to the processing container and including a capacitive component;
A substrate is placed on the lower electrode;
The first impedance adjustment unit has an impedance value at a frequency of the first high-frequency power source from the upper electrode through the plasma, the lower electrode, and the wall of the processing container to the ground casing of the first matching circuit. The impedance value is adjusted to be smaller than the impedance value at the frequency of the first high-frequency power source from the upper electrode through the plasma and the wall of the processing vessel to the grounded casing of the first matching circuit. Is for
The second impedance adjustment unit has an impedance value at a frequency of the second high-frequency power source from the lower electrode to the ground casing of the second matching circuit through the plasma, the upper electrode, and the wall of the processing container. The impedance value is adjusted to be smaller than the impedance value at the frequency of the second high-frequency power source from the lower electrode through the plasma and the wall of the processing container to the ground casing of the second matching circuit. A plasma processing apparatus characterized in that: In a plasma processing apparatus for converting a processing gas into plasma with high-frequency power in a processing container and processing the substrate with the plasma,
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high-frequency power source of 10 MHz to 30 MHz having one end connected to the upper electrode via a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
A first impedance adjustment unit including one end side connected to the lower electrode and the other end side connected to the processing container, and including a capacitance component;
A second impedance adjusting unit including one end side connected to the upper electrode and the other end side connected to the processing container and including a capacitive component;
A substrate is placed on the lower electrode;
The first impedance adjustment unit has a minimum impedance value at the frequency of the first high-frequency power source from the upper electrode through the plasma, the lower electrode, and the wall of the processing container to the grounded casing of the first matching circuit. Is to adjust the impedance value so that
The second impedance adjustment unit has an impedance value at a frequency of the second high-frequency power source from the lower electrode through the plasma, the upper electrode, and the wall of the processing container to the ground casing of the second matching circuit. A plasma processing apparatus for adjusting an impedance value so as to be minimized. The first impedance adjustment unit adjusts the impedance value so that a value within 10% of the maximum value is obtained when the high-frequency current value of the first high-frequency power source flowing into the lower electrode is changed. Value is set,
The second impedance adjustment unit adjusts the impedance value so that when the high-frequency current value of the second high-frequency power source flowing into the upper electrode is changed, a value within 10% of the maximum value is obtained. 10. The plasma processing apparatus according to claim 8, wherein a value is set.   The first impedance adjustment unit and the second impedance adjustment unit are configured to be able to vary the impedance value at the frequency of the first high-frequency power source and the impedance value at the frequency of the second high-frequency power source, respectively. The plasma processing apparatus according to claim 8 or 9.   Data in which the type of plasma processing is associated with the adjustment values of the first impedance adjustment unit and the second impedance adjustment unit is stored, and the impedance adjustment value corresponding to the selected type of plasma processing is read out and the first 10. The plasma processing apparatus according to claim 8, further comprising a control unit that outputs a control signal for adjusting the impedance adjustment unit and the second impedance adjustment unit.   The first impedance adjustment unit is a dielectric that forms a capacitive component provided between the lower electrode and the processing container, and the second impedance adjustment unit is a capacitance provided between the upper electrode and the processing container. 10. The plasma processing apparatus according to claim 8, wherein the plasma processing apparatus is a dielectric material. A plurality of first impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a part of the lower electrode that is separated from each other in the lateral direction,
The plasma processing according to claim 8 or 9, wherein a plurality of second impedance adjustment sections are used, and one end side of each impedance adjustment section is connected to a portion of the upper electrode that is laterally separated from each other. apparatus. In a plasma processing apparatus for converting a processing gas into plasma with high-frequency power in a processing container and processing the substrate with the plasma,
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high frequency power source of 10 MHz to 30 MHz having one end connected to the lower electrode through a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
The one end side is connected to the upper electrode, the other end side is connected to the processing container, and includes a first impedance adjustment unit and a second impedance adjustment unit including a capacitance component,
A substrate is placed on the lower electrode;
The first impedance adjustment unit has an impedance value at a frequency of the first high-frequency power source from the lower electrode to the ground casing of the first matching circuit through the plasma, the upper electrode, and the wall of the processing container. In order to adjust the impedance value so as to be smaller than the impedance value at the frequency of the first high-frequency power source from the lower electrode through the plasma and the wall of the processing vessel to the grounded casing of the first matching circuit. And
The second impedance adjustment unit has an impedance value at a frequency of the second high-frequency power source from the lower electrode to the ground casing of the second matching circuit via the plasma, the upper electrode, and the wall of the processing container. In order to adjust the impedance value to be smaller than the impedance value at the frequency of the second high-frequency power source from the lower electrode through the plasma and the wall of the processing vessel to the grounded housing of the second matching circuit. A plasma processing apparatus characterized by the above. In a plasma processing apparatus for converting a processing gas into plasma with high-frequency power in a processing container and processing the substrate with the plasma,
An upper electrode and a lower electrode which are insulated from the processing container and provided vertically opposite each other in the processing container;
A first high frequency power source of 10 MHz to 30 MHz having one end connected to the lower electrode through a first matching circuit;
A second high frequency power source of 2 MHz to 6 MHz, one end of which is connected to the lower electrode via a second matching circuit;
The one end side is connected to the upper electrode, the other end side is connected to the processing container, and includes a first impedance adjustment unit and a second impedance adjustment unit including a capacitance component,
A substrate is placed on the lower electrode;
The first impedance adjustment unit has a minimum impedance value at the frequency of the first high-frequency power source from the lower electrode through the plasma, the upper electrode, and the wall of the processing container to the grounded casing of the first matching circuit. Is to adjust the impedance value so that
The second impedance adjustment unit has a minimum impedance value at the frequency of the second high-frequency power source from the lower electrode through the plasma, the upper electrode, and the wall of the processing container to the ground casing of the second matching circuit. A plasma processing apparatus for adjusting the impedance value so that The first impedance adjustment unit adjusts the impedance value so that when the high-frequency current value of the first high-frequency power source flowing into the upper electrode is changed, a value within 10% of the maximum value is obtained. Value is set,
The second impedance adjustment unit adjusts the impedance value so that when the high-frequency current value of the second high-frequency power source flowing into the upper electrode is changed, a value within 10% of the maximum value is obtained. The plasma processing apparatus according to claim 15 or 16, wherein a value is set.   The first impedance adjustment unit and the second impedance adjustment unit are configured to be able to vary the impedance value at the frequency of the first high-frequency power source and the impedance value at the frequency of the second high-frequency power source, respectively. The plasma processing apparatus according to claim 15 or 16.   Data in which the type of plasma processing is associated with the adjustment values of the first impedance adjustment unit and the second impedance adjustment unit is stored, and the impedance adjustment value corresponding to the selected type of plasma processing is read out and the first 17. The plasma processing apparatus according to claim 15, further comprising a control unit that outputs a control signal for adjusting the impedance adjustment unit and the second impedance adjustment unit.   17. The plasma according to claim 15, wherein each of the first impedance adjustment unit and the second impedance adjustment unit is a dielectric that forms a capacitive component provided between the upper electrode and the processing vessel. Processing equipment. A plurality of first impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a part of the lower electrode that is separated from each other in the lateral direction,
The plasma processing according to claim 15 or 16, wherein a plurality of second impedance adjustment units are used, and one end side of each impedance adjustment unit is connected to a portion of the lower electrode that is laterally separated from each other. apparatus. The plasma processing apparatus according to claim 1, wherein an area of the substrate is 1 m ² or more.   23. The plasma processing apparatus according to claim 22, wherein the total value of the high-frequency power used is 10 kW or more. The cathode electrode and the anode electrode constitute an upper electrode and a lower electrode, respectively.
The frequency of the high frequency power supply is 10 MHz to 30 MHz,
The area of the substrate is 1 m ² or more,
The gap between the upper electrode and the lower electrode is 50 mm to 300 mm, the processing pressure is 13 Pa to 27 Pa,
The plasma processing apparatus according to claim 1, wherein an etching process is performed on the substrate with a processing gas containing halogen. The cathode electrode and the anode electrode constitute a lower electrode and an upper electrode, respectively.
The frequency of the high frequency power supply is 10 MHz to 30 MHz,
The area of the substrate is 1 m ² or more,
The gap between the upper electrode and the lower electrode is 200 mm to 700 mm, the processing pressure is 0.7 Pa to 13 Pa,
The plasma processing apparatus according to claim 1, wherein an etching process is performed on the substrate with a processing gas containing halogen. The area of the substrate is 1 m ² or more,
A first high frequency power source is connected to the upper electrode side;
The gap between the upper electrode and the lower electrode is 50 mm to 300 mm, the processing pressure is 13 Pa to 27 Pa,
10. The plasma processing apparatus according to claim 8, wherein an etching process is performed on the substrate with a processing gas containing halogen. The area of the substrate is 1 m ² or more,
A first high frequency power source is connected to the lower electrode side;
The gap between the upper electrode and the lower electrode is 200 mm to 700 mm, the processing pressure is 0.7 Pa to 13 Pa,
The plasma processing apparatus according to claim 15, wherein an etching process is performed on the substrate with a processing gas containing halogen.

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