CN1745463A - Plasma processing apparatus, electrode plate for plasma processing apparatus, and electrode plate manufacturing method - Google Patents

Abstract

A plasma processing apparatus for performing a plasma process on a substrate (W) to be processed includes a processing container (10) capable of reducing pressure for accommodating the substrate to be processed. A first electrode (12) is disposed in the processing chamber. A supply system (62) is provided for supplying a process gas into the process container. An electric field forming system (32) for forming a high-frequency electric field in the processing container is arranged for generating plasma of the processing gas. A plurality of projections (70) projecting toward the plasma generation space are formed discretely on the main surface of the first electrode (12).

Description

Plasma processing device, electrode plate for plasma processing device, and electrode plate manufacturing method

technical field

The present invention relates to a technology for performing plasma processing on a substrate to be processed, and in particular to a high-frequency discharge plasma processing technology in which high-frequency waves are supplied to electrodes to generate plasma. In particular, the present invention relates to plasma processing techniques utilized in semiconductor processing for the manufacture of semiconductor devices. Here, the so-called semiconductor processing refers to forming semiconductor layers, insulating layers, conductive layers, etc. in a predetermined pattern on semiconductor wafers or glass substrates for LCD (liquid crystal display) Various processes are performed to manufacture structures including semiconductor devices, wiring and electrodes connected to the semiconductor devices on the substrate to be processed.

Background technique

In processes such as etching, deposition, oxidation, and sputtering in the manufacturing process of semiconductor devices or FPDs, plasma is often used in order to perform a good reaction in a process gas at a relatively low temperature. In general, plasma processing apparatuses can be roughly divided into methods of generating plasma using corona (glow) discharge or high-frequency discharge, and using microwaves.

In a high-frequency discharge type plasma processing apparatus, an upper electrode and a lower electrode are arranged in parallel in a processing container or a reaction chamber. A substrate to be processed (semiconductor wafer, glass substrate, etc.) is placed on the lower electrode, and a high-frequency voltage for plasma generation is applied to the upper electrode or the lower electrode via an integrator. Electrons are accelerated by the high-frequency electric field generated by the high-frequency voltage, and plasma is generated by impact ionization of the electrons and the process gas.

Recently, high-density plasma at low pressure is required for plasma processing as design rules in manufacturing processes are miniaturized. Therefore, in plasma processing apparatuses of the high-frequency discharge system as described above, frequencies in the high-frequency range (50 MHz or more) much higher than conventional frequencies (generally 27 MHz or less) have come to be used. However, if the frequency of high-frequency discharge is increased, the high-frequency power applied to the inside of the electrode from the high-frequency power supply through the power supply rod will be transmitted to the surface of the electrode due to the skin effect, and will be transferred from the main surface of the electrode (the surface opposite to the plasma). The edges flow to the center. When a high-frequency current flows from the edge to the center on the same electrode main surface, the electric field intensity at the center of the electrode main surface becomes higher than that at the edge. Therefore, the density of the generated plasma is also higher at the center of the electrode than at the edge of the electrode. At the center of the electrode with high plasma density, the resistivity of the plasma decreases, and at the opposite electrode, the current also concentrates at the center of the electrode, and the non-uniformity of the plasma density is further enhanced.

In order to solve this problem, it is known to form the central part of the main surface of the high-frequency electrode with a high-resistance member (for example, Japanese Patent Laid-Open No. 2000-323456). In this method, the central portion of the main surface (plasma contact surface) of the electrode connected to the high-frequency power supply side is formed of a high-resistance member. A large amount of high-frequency power is consumed as Joule heat by this high-resistance member, so that the electric field intensity on the main surface of the electrode is relatively lower in the center of the electrode than in the outer periphery of the electrode. Thereby, the above-mentioned non-uniformity of the plasma density is corrected.

However, in the plasma processing apparatus of the above-mentioned high-frequency discharge method, the central part of the main surface of the high-frequency electrode is composed of a high-resistance member, and there is an increase in the consumption (energy loss) of high-frequency power due to Joule heat. possibility.

Contents of the invention

The present invention is made in view of the problems of the prior art, and an object of the present invention is to provide a high-frequency discharge type plasma processing apparatus capable of effectively uniformizing plasma density and an electrode plate for the plasma processing apparatus .

Another object of the present invention is to provide an electrode plate manufacturing method capable of efficiently producing a structure in which an electrostatic chuck is integrally provided on an electrode plate for a plasma processing apparatus according to the present invention.

In order to achieve the above object, the first plasma processing apparatus of the present invention is provided with a first electrode in a decompressible processing container, a high-frequency electric field is formed in the processing container, and a processing gas is flowed in to generate plasma of the processing gas. , a plasma processing apparatus for performing desired plasma processing on a substrate to be processed under the plasma, wherein, on the main surface of the first electrode, there are discretely provided multiple electrodes protruding toward the space where the plasma is generated. a convex part. In this device configuration, if the high frequency for plasma generation can be applied to the first electrode, it is also possible to apply the high frequency to other electrodes, for example, to the second electrode opposite to the first electrode in a parallel plate type. of. When a high frequency is applied to the first electrode, the high frequency may be supplied from the back surface on the side opposite to the main surface of the first electrode.

When the high-frequency current is supplied to the first electrode from the back side in this way, when the high-frequency current flows from the edge of the electrode to the center of the electrode on the main surface of the first electrode due to the skin effect, the high-frequency current flows through the main surface of the first electrode. The surface layer of the convex part. Since the convex portion protrudes toward the plasma space side, it is electrically connected to the plasma at a lower impedance than the portion other than the convex portion, that is, the bottom portion of the main surface. Therefore, the high-frequency electric power moved by the high-frequency current flowing through the surface layer of the main surface of the electrode is mainly emitted to the plasma from the top surface of the convex portion. In this way, each of the plurality of convex portions discretely provided on the main surface of the first electrode functions as a small electrode for supplying high-frequency power to the plasma. By appropriately selecting the properties (shape, size, interval, density, etc.) of the protrusions, the high-frequency power supply characteristics of the first electrode to plasma can be controlled to desired characteristics.

For example, in order to ensure the high-frequency power supply function at the above-mentioned convex portion, it is preferable that on the main surface of the first electrode, the height of the convex portion and the radial width of the electrode be taken as expressed by the following formula (1): more than three times the surface depth δ:

δ＝(2/ωσμ) ^1/2 ... (1)

In the formula, ω=2πf (f: frequency), σ: electrical conductivity, μ: magnetic permeability.

In addition, in order to improve the uniformity of the electric field intensity or plasma density in the radial direction of the electrode, it is preferable to gradually increase the area density of the protrusions from the center of the electrode to the edge of the electrode on the main surface of the first electrode. . For example, when the protrusions are formed in a constant size, a distribution characteristic in which the number density of the protrusions gradually increases from the center of the electrode to the edge of the electrode can be obtained.

In addition, as a preferred mode, the protrusion may be formed in a columnar shape. Alternatively, it is also possible to form the respective convex portions in an annular shape and arrange them concentrically as a whole.

In addition, in order to improve the high-frequency power discharge function generated by the above-mentioned convex portion, it is preferable to provide a dielectric body on at least the upper surface of the portion other than the convex portion on the main surface of the first electrode.

In the second plasma processing apparatus of the present invention, a first electrode is provided in a decompressible processing container, a high-frequency electric field is formed in the processing container, and a processing gas is flowed in to generate plasma of the processing gas. The following plasma processing apparatus for performing desired plasma processing on a substrate to be processed, wherein a plurality of recessed recesses are provided on the main surface of the first electrode relatively discretely from the space where the plasma is generated. Also in this device configuration, if high frequency for plasma generation can be applied to the first electrode, it is also possible to apply high frequency to other electrodes such as the second electrode opposite to the first electrode in a parallel plate type. When a high frequency is applied to the first electrode, the high frequency may be supplied from the back surface on the side opposite to the main surface of the first electrode.

Since the recessed portion on the main surface of the first electrode is recessed opposite to the plasma space side, it is electrically connected to the plasma with higher impedance than the portion other than the recessed portion (the top portion of the main surface of the electrode). Therefore, the high-frequency power moved by the high-frequency current flowing through the surface layer of the main surface of the first electrode is mainly emitted to the plasma from the portion other than the concave portion (the top portion of the main surface of the electrode). In this way, each of the plurality of concave portions discretely arranged on the main surface of the first electrode functions as an electrode mask for suppressing the supply of high-frequency power to the plasma. By appropriately selecting the properties (shape, size, spacing, density, etc.) of the recesses, the effect of the first electrode on plasma generation can be controlled to desired characteristics.

For example, in order to ensure the high-frequency power supply mask function generated by the above-mentioned recesses, it is preferable to set the height of the recesses and the width in the electrode radial direction on the main surface of the first electrode to be three times or more the above-mentioned surface depth δ.

In addition, in order to increase the uniformity of electric field intensity or plasma density in the radial direction of the electrode, it is preferable to gradually increase the area density of the recesses from the center of the electrode to the edge of the electrode on the main surface of the first electrode. For example, when the recesses are formed to a certain size, a distribution characteristic such that the number density of the recesses gradually decreases from the center of the electrode to the edge of the electrode can be adopted.

In addition, as a preferred mode, the concave portion may be formed in a cylindrical shape. Alternatively, in order to improve the high-frequency power supply masking function generated by the recesses as described above, it is preferable to provide a dielectric body at least in the recesses on the main surface of the first electrode.

In the third plasma processing apparatus of the present invention, a first electrode is provided in a decompressible processing container, a high-frequency electric field is formed in the processing container, and a processing gas is flowed in to generate plasma of the processing gas. The following is a plasma processing apparatus for performing desired plasma processing on a substrate to be processed, wherein a dielectric body is provided on the main surface of the first electrode, and the dielectric body on the central portion side of the first electrode The thickness is larger than the thickness of the above-mentioned dielectric body on the electrode edge side. Also in this device configuration, if high frequency for plasma generation can be applied to the first electrode, it is also possible to apply high frequency to other electrodes such as the second electrode opposite to the first electrode in a parallel plate type. When a high frequency is applied to the first electrode, the high frequency may be supplied from the back surface on the side opposite to the main surface of the first electrode.

In the above-mentioned device configuration, since the impedance of the central part of the electrode opposite to the plasma space side is large and the impedance of the edge part of the electrode is low, the high-frequency electric field on the side of the edge part of the electrode is strengthened, and on the other hand, the center of the electrode The high-frequency electric field on the part side is weakened, thereby improving the uniformity of electric field strength or plasma density.

In the above device configuration, the dielectric body preferably has a profile in which the thickness of the dielectric body decreases gradually (preferably arched) from the electrode center side to the electrode edge side of the first electrode. In addition, it is preferable to have a structure in which the thickness of the dielectric body is almost constant on the inner side of the first diameter including the center portion of the electrode. In this case, at the outside of the first diameter, the thickness of the dielectric may decrease obliquely toward the edge of the electrode, or may be almost constant at the inside of the second diameter larger than the first diameter. The outer portion of the second diameter decreases obliquely toward the electrode edge portion side. The area size of the dielectric body can be set arbitrarily according to the size of the substrate to be processed, but typically it can be set to be almost the same size. That is, the position of the edge portion where the thickness of the dielectric body becomes the smallest may be set near the position facing the edge portion of the substrate to be processed. In addition, since there is a certain correlation between the permittivity of the dielectric body giving good in-plane uniformity and the thickness of the dielectric body at the center portion of the electrode, as long as the As for the permittivity, the thickness of the dielectric body at the center of the electrode may be set.

In addition, as a preferred aspect, a conductive shielding member covering a part of the dielectric body, for example, the vicinity of the edge may be provided on the main surface of the first electrode. With this configuration, it is possible to weaken the electric field intensity reducing effect of the dielectric in the area covered by the shield member, and the electric field intensity distribution can be adjusted by changing the shape and/or size of the opening of the shield member. It is preferable that the shielding member is attached detachably, that is, replaceably.

In addition, as a preferable mode, on the main surface of the first electrode, the electrode portion outside the position radially outward from the outer peripheral edge of the dielectric body by a desired distance protrudes into the plasma generation space by a desired amount. composition. In this electrode structure, the electric field intensity distribution characteristic is controlled or adjusted in the direction of increasing the electric field intensity in the region near the edge of the substrate to be processed by providing the protruding portion radially outside the dielectric body. The electric field intensity distribution control performed by the protruding part can be increased, decreased or changed by the protruding amount of the protruding part or the position of the protruding step part.

In addition, as another preferred aspect, a configuration in which the dielectric body protrudes by a desired protrusion amount into the plasma generation space is also possible on the main surface of the first electrode. In this electrode structure, at each position of the plasma generation space facing the dielectric body, the protrusion amount of the dielectric body controls or adjusts the electric field intensity distribution characteristic in the direction of increasing the electric field intensity.

Furthermore, if another preferred mode is adopted, on the main surface of the first electrode, a cavity is provided inside the dielectric body, and a fluid dielectric substance (preferably an organic solvent) is filled in the cavity. ). In this configuration, it is possible to arbitrarily adjust the dielectric constant of the entire dielectric body by appropriately selecting or setting the amount of the dielectric substance that enters the cavity or the shape of the occupied space. The cavity may also be formed in a solid dielectric, and at least a surface of the main surface of the first electrode may be formed of a solid, and an inner wall or recess may be formed of an electrode base material (conductor).

In the first, second, or third plasma processing apparatus described above, even when no high frequency is applied to the first electrode provided with the above-mentioned convex portion, concave portion, or dielectric body, for example, even if the first electrode Even when grounded to the ground potential, the same effect as above can be produced on the plasma generation space.

In the plasma processing apparatus of the present invention, the electrostatic chuck used to adsorb and hold the substrate to be processed by Coulomb force can be arranged on the main surface of the first electrode on the side of the high-frequency power supply, or it can also be arranged on the opposite electrode. , that is, the main surface of the second electrode. When the electrostatic chuck is provided on the main surface of the first electrode, the second electrode is connected to the ground potential through the processing container, and high-frequency current in the plasma can flow to the ground through the processing container.

The first electrode plate used in the plasma processing apparatus of the present invention is an electrode plate provided in a processing container for generating plasma in a high-frequency discharge type plasma processing apparatus, and the main surface facing the plasma A plurality of protrusions are discretely provided. The electrode plate of this configuration can obtain the same function as that of the first or second electrode in the above-mentioned first plasma processing apparatus.

The electrode plate manufacturing method of the present invention for manufacturing the first electrode plate includes the step of covering the main surface of the electrode main body with a mask having openings corresponding to the protrusions, and facing the main surface of the electrode main body from the upper side of the mask. a step of forming the protrusion in the opening by sputtering a conductive metal or semiconductor on the main surface; and a step of removing the mask from the main surface of the electrode main body.

The second electrode plate used in the plasma processing apparatus of the present invention is an electrode plate provided in a processing container for generating plasma in a high-frequency discharge type plasma processing apparatus, and is discrete on the main surface facing the plasma. The ground is provided with a plurality of recesses. The electrode plate of this configuration can obtain the same function as that of the first or second electrode in the above-mentioned second plasma processing apparatus.

The electrode plate manufacturing method of the present invention for manufacturing the second electrode plate includes the step of covering the main surface of the electrode substrate with a mask having openings corresponding to the recesses, and facing the surface of the electrode substrate from the upper surface of the mask. A step of forming the concave portion by spraying solid particles or liquid on the main surface to physically remove the portion of the electrode substrate inside the opening, and a step of removing the mask from the main surface of the electrode substrate.

In the electrode plate manufacturing method of the present invention, it is preferable to include a step of forming a first dielectric film by sputtering a dielectric on the main surface of the electrode substrate from which the mask has been removed. Accordingly, a dielectric body for improving the impedance ratio can be provided on the portion of the first electrode plate other than the convex portion, and on the second electrode plate, inside the concave portion.

In addition, in order to integrally install the electrostatic chuck on the first electrode plate or the second electrode plate, it is preferable to form a first dielectric film covering the entire main surface of the electrode substrate and spray An electrode film for an electrostatic chuck is formed by plating an electrode material, and a dielectric is sprayed on the upper surface of the electrode film to form a second dielectric film. According to this method, the dielectric body for improving the impedance ratio and the lower insulating film for the electrostatic chuck can be integrally formed simultaneously on the main surface of the first or second electrode plate.

The third electrode plate used in the plasma processing apparatus of the present invention is an electrode plate provided in a processing container for generating plasma in a high-frequency discharge type plasma processing apparatus, and the main surface facing the plasma A dielectric is provided such that the thickness of the dielectric at the center of the first electrode is greater than the thickness of the dielectric at the edge of the electrode. The electrode plate of this configuration can obtain the same function as that of the first or second electrode in the above-mentioned third plasma processing apparatus.

Description of drawings

FIG. 1 is a longitudinal sectional view showing the configuration of a plasma etching apparatus according to one embodiment of the present invention.

Fig. 2 is a plan view showing a base structure according to a first embodiment of the present invention.

3 is a partially enlarged longitudinal sectional view showing a base structure according to a first embodiment of the present invention.

4 is a graph showing an example of the number density distribution characteristic of protrusions in the base structure according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram showing the configuration of high-frequency discharge in the plasma etching apparatus shown in FIG. 1 .

6 is a plan view showing the directivity of a high-frequency current flowing through a high-frequency electrode on a main surface in the plasma etching apparatus shown in FIG. 1 .

7 is a schematic longitudinal sectional view showing the flow of high-frequency current and the radiation of high-frequency power (electric field) in the susceptor structure of the first embodiment.

8 is a characteristic diagram showing an attenuation characteristic in the depth direction of an electromagnetic wave (high-frequency current) flowing through a conductor.

9 is a graph showing electric field intensity distribution characteristics in the radial direction of the electrode when the ratio of the number density of protrusions at the electrode center portion and the edge portion is used as a parameter in the first embodiment.

10 is a partial longitudinal sectional view showing a structure in which an electrostatic chuck is integrally provided on a susceptor according to the first embodiment.

FIG. 11 is a graph showing the impedance ratio characteristics of a convex portion and a bottom portion in the base structure with an electrostatic chuck shown in FIG. 10 .

12A to 12F are diagrams illustrating a method of manufacturing the base structure with an electrostatic chuck shown in FIG. 10 in order of steps.

FIG. 13 is a diagram showing a modified example of the base structure according to the first embodiment.

14 is a longitudinal sectional view showing a configuration example in which the electrode protrusion structure is applied to the upper electrode according to the first embodiment.

15 is a plan view showing an electrode structure according to a second embodiment of the present invention.

Fig. 16 is a partially enlarged longitudinal sectional view showing the electrode structure of Fig. 15 .

FIG. 17 is a graph showing an example of the number density distribution characteristic of recesses in the electrode structure of FIG. 15 .

18A to 18F are diagrams showing, in order of steps, a method of manufacturing a structure in which an electrostatic chuck is integrally provided on an electrode structure according to the second embodiment.

FIG. 19 is a plan view showing a structure of a lower electrode according to a third embodiment.

20 is a plan view showing an upper electrode according to a third embodiment.

FIG. 21 is a diagram showing an example of the parallel plate electrode structure in the third embodiment.

FIG. 22 is a graph showing the electric field intensity distribution characteristics in the radial direction between electrodes in the parallel plate electrode structure of FIG. 21 with the film thickness at the center of the upper electrode as a parameter.

23A to 23D are diagrams showing more specific examples of the film thickness profile of the dielectric film of the upper electrode in the third embodiment.

24A and 24B are graphs showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained from the example and the ideal profile of FIGS. 23A to 23D , respectively.

25A to 25D are diagrams showing another more specific example of the film thickness profile of the dielectric film of the upper electrode in the third embodiment.

26A and 26B are graphs showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of FIGS. 25A to 25D .

27A to 27C are diagrams showing another more specific example of the film thickness and film quality profile of the dielectric film of the upper electrode in the third embodiment.

28A and 28B are graphs showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of FIGS. 27A to 27C .

FIG. 29 is a graph showing the correlation between the dielectric constant of a dielectric film and the film thickness at the center of the electrode, which are created from the data points in FIGS. 28A and 28B and which give practically sufficient in-plane uniformity.

30A and 30B are diagrams comparing the etching rate distribution characteristics of organic film etching with Example A and Comparative Example B in which the third embodiment is applied to the upper electrode.

31A and 31B are diagrams comparing an example and a comparative example in which the third embodiment is applied to the structure of the lower electrode.

FIGS. 32A and 32B are graphs comparing the etching rate distribution characteristics of organic film etching with respect to the example shown in FIG. 31A and the comparative example shown in FIG. 31B .

33A and 33B are partial cross-sectional views of an example of an upper electrode structure according to another embodiment of the present invention.

Fig. 34 is a graph showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of Figs. 33A and 33B.

35A to 35C are partial cross-sectional views showing examples, comparative examples, and reference examples, respectively, of upper electrode structures according to yet another embodiment of the present invention.

FIG. 36 is a graph showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained from the examples, the comparative example, and the reference example shown in FIGS. 35A to 35C .

37A to 37C are partial cross-sectional views showing other two examples and a comparative example of the structure of the upper electrode, respectively.

FIG. 38 is a graph showing the distribution characteristics of the etching rate (normalized value) of oxide film etching obtained from the examples and comparative examples in FIGS. 37A to 37C , respectively.

39A to 39C are partial cross-sectional views showing an example, a comparative example, and a reference example, respectively, of an upper electrode structure according to yet another embodiment of the present invention.

FIG. 40 is a graph showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained from the examples, the comparative example, and the reference example shown in FIGS. 39A to 39C .

FIG. 41 is a partial cross-sectional view showing the structure of an upper electrode according to a modified example of the embodiment shown in FIGS. 35A to 38 .

42A to 42D are partial cross-sectional views showing the structure of the upper electrode according to still another embodiment of the present invention.

Fig. 43 is a partial cross-sectional view showing a specific example of the embodiments shown in Figs. 42A to 42D.

Fig. 44 is a graph showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of Fig. 43 .

45A to 45D are partial cross-sectional views showing the structure of an upper electrode according to a modified example of the embodiment shown in FIGS. 42A to 42D .

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings. However, in the following description, constituent elements having substantially the same functions and configurations are denoted by the same reference numerals, and descriptions are repeated only when necessary.

FIG. 1 is a longitudinal sectional view showing the configuration of a plasma etching apparatus according to one embodiment of the present invention. This plasma processing apparatus is configured as an RIE type plasma etching apparatus. The plasma processing apparatus has a cylindrical chamber (processing container) 10 made of metal such as aluminum or stainless steel. Chamber 10 is safety grounded.

In the chamber 10, a disc-shaped lower electrode or a susceptor 12 on which a semiconductor wafer W is placed as a substrate to be processed, for example, is arranged. The base 12 is made of, for example, aluminum, and is supported by a cylindrical support portion 16 extending vertically upward from the bottom surface of the chamber 10 via an insulating cylindrical holding portion 14 . On the upper surface of the cylindrical holding portion 14, a focus ring 18 made of, for example, quartz is arranged to surround the upper surface of the susceptor 12 in a ring shape.

An exhaust passage 20 is formed between the side wall of the chamber 10 and the cylindrical support portion 16 . An annular partition plate 22 is attached to the entrance or in the middle of the exhaust passage 20, and an exhaust port 24 is arranged at the bottom. An exhaust device 28 is connected to the exhaust port 24 via an exhaust pipe 26 . The exhaust device 28 has a vacuum pump, and can reduce the pressure of the processing space in the chamber 10 to a predetermined vacuum degree. A gate valve 30 for opening and closing the loading and unloading port of the semiconductor wafer is attached to the side wall of the chamber 10 .

A high-frequency power supply 32 for plasma generation is electrically connected to the susceptor 12 via an integrator 34 and a power supply rod 36 . The high-frequency power supply 32 applies a predetermined high-frequency, for example, 60 MHz high-frequency power to the lower electrode, that is, the susceptor 12 . Among them, on the ceiling portion of the chamber 10 , a shower head 38 described later is arranged as an upper electrode at a ground potential. Therefore, a high-frequency voltage from the high-frequency power supply 32 is capacitively applied between the susceptor 12 and the shower head 38 .

On the upper surface of the susceptor 12, an electrostatic chuck 40 for holding the semiconductor wafer W by electrostatic attraction is arranged. In this electrostatic chuck 40, an electrode 40a made of a conductive film is sandwiched between a pair of insulating films 40b and 40c. The DC power supply 42 is electrically connected to the electrode 40 a via a switch 43 . The semiconductor wafer W can be sucked and held on the susceptor by Coulomb force by the DC voltage from the DC power supply 42 .

Inside the susceptor 12 , for example, a coolant chamber 44 extending in the circumferential direction is disposed. In the coolant chamber 44 , a coolant of a predetermined temperature, such as cooling water, is circulated and supplied from the refrigeration unit 46 through the pipes 48 and 50 . The processing temperature of the semiconductor wafer W on the electrostatic chuck 40 is controlled by the temperature of the coolant. Furthermore, a heat transfer gas such as He gas from the heat transfer gas supply unit 52 is supplied between the upper surface of the electrostatic chuck 40 and the bottom surface of the semiconductor wafer W via the gas supply line 54 .

The shower head 38 of the ceiling portion includes a lower electrode plate 56 having a plurality of gas vent holes 56 a, and an electrode support 58 detachably supporting the electrode plate 56 . A buffer chamber 60 is provided inside the electrode support 58 , and a gas supply pipe 64 from a processing gas supply unit 62 is connected to a gas introduction port 60 a of the buffer chamber 60 .

Around the chamber 10, a ring-shaped or concentrically extended magnet 66 is arranged. In the chamber 10 , in the space between the shower head 38 and the susceptor 12 , an RF electric field in a vertical direction is formed by the high-frequency power supply 32 . High-density plasma can be generated near the surface of susceptor 12 by high-frequency discharge.

In order to control the operations of various parts in the plasma etching apparatus, such as the exhaust device 28, the high-frequency power supply 32, the switch 43 for the electrostatic chuck, the cooling unit 46, the heat transfer gas supply part 52, and the processing gas supply part 62, etc., And a control unit 68 is provided. The control unit 68 is also connected to a host computer (not shown) and the like.

In this plasma etching apparatus, when performing etching, the following operations are performed. That is, first, the gate valve 30 is opened, and the semiconductor wafer W to be processed is carried into the chamber 10 and placed on the electrostatic chuck 40 . Then, an etching gas (generally, a mixed gas) is introduced into the chamber 10 at a predetermined flow rate and flow ratio from the processing gas supply unit 62 , and the pressure in the chamber 10 is brought to a set value by the exhaust device 28 . Further, high-frequency power is supplied to the susceptor 12 from the high-frequency power supply 32 at a predetermined power. Further, the semiconductor wafer W is fixed on the electrostatic chuck 40 by applying a DC voltage to the electrode 40 a of the electrostatic chuck 40 by the DC power supply 42 . The etching gas ejected from the shower head 38 is converted into plasma between the electrodes 12 and 38 by high-frequency discharge, and the main surface of the semiconductor wafer W is etched by radicals or ions generated by the plasma.

In this plasma etching apparatus, a high frequency (50 MHz or more) significantly higher than the conventional frequency range (generally 27 MHz or less) is applied to the susceptor (lower electrode) 12 . Therefore, the density of plasma is increased in an optimal dissociation state, and high-density plasma can be formed even under lower pressure conditions.

Fig. 2, Fig. 3 and Fig. 4 are plan views respectively showing the base structure (base) 12 according to the first embodiment of the present invention, showing an enlarged longitudinal sectional view of the structure, and showing the number of protrusions in the structure A graph showing an example of density distribution characteristics. On the main surface of the susceptor 12 (the upper surface of the susceptor 12 in this embodiment, that is, the surface on the side of the plasma generation space), a plurality of cylindrical tubes of a certain size composed of conductors or semiconductors are discretely arranged. convex portion 70 . Each of these protrusions 70 constitutes a small electrode for applying high-frequency power or a high-frequency electric field to the plasma. Preferably, as shown in FIG. 4, the number density distribution or the area density distribution gradually increases from the center of the electrode to the edge of the electrode, and it is arranged on the main surface of the base 12.

FIG. 5 is a schematic diagram showing the configuration of high-frequency discharge in the plasma etching apparatus shown in FIG. 1 . As shown in FIG. 5, if high-frequency power from the high-frequency power supply 32 is supplied to the susceptor 12, a high-frequency discharge is generated between the susceptor (lower electrode) 12 and the upper electrode 38 near the semiconductor wafer W. Plasma PZ of etching gas. The generated plasma PZ spreads around, especially upward and radially outward. The electron current or ion current in the plasma PZ flows toward the ground through the upper electrode 38 or the chamber side wall.

6 is a plan view showing the directionality of a high-frequency current flowing through a main surface of a high-frequency electrode in the plasma etching apparatus shown in FIG. 1 . At the base 12 , high frequency power is applied from the high frequency power supply 32 via the power supply rod 36 to the inside or back of the base, and propagates to the electrode surface layer due to the skin effect. As shown in FIG. 6 , the high-frequency current i flows in an anti-radial manner on the main surface of the susceptor 12 from the edge to the center.

7 is a schematic cross-sectional view showing the flow of high-frequency current and the radiation of high-frequency power (electric field) in the susceptor structure (the susceptor 12 ) of the first embodiment. As shown in FIG. 7 , in the present embodiment, a high-frequency current i flows through the surface layer of the protrusion 70 on the main surface of the susceptor 12 . Since the convex portion 70 protrudes toward the upper electrode 38 side, that is, the plasma PZ side, it is electrically connected to the plasma PZ at an impedance lower than that of the bottom portion 12 a of the main surface. Therefore, the high-frequency power moved by the high-frequency current i flowing in the surface layer of the main surface of the susceptor 12 is mainly emitted from the tip of the convex portion 70 to the plasma PZ.

However, as shown in FIG. 3 , a configuration in which a dielectric body 72 is provided around the convex portion 70 (on the bottom surface portion 12 a ) is preferable. Therefore, the impedance ratio Z _12a /Z ₇₀ between the convex portion 70 and the bottom portion 12a can be increased on the main surface of the base 12 . That is, the rate of high-frequency power supplied to the plasma PZ through the convex portion 70 or the power supply rate can be increased.

In this manner, in the present embodiment, each of the plurality of convex portions 70 discretely provided on the main surface of the susceptor 12 functions as a small electrode for supplying high-frequency power to the plasma PZ. By selecting the properties (shape, size, spacing, density, etc.) of the protrusions 70, the high-frequency power supply characteristics of the susceptor 12, which is an aggregate of small electrodes, can be set to desired characteristics.

For example, as described above ( FIG. 4 ), the number density of the protrusions 70 may be such that the distribution characteristic gradually increases from the center of the electrode to the edge of the electrode. Therefore, as shown in FIG. 9 , the uniformity of the high-frequency electric power or high-frequency electric field given to the plasma PZ by the susceptor 12 (in particular, the uniformity in the radial direction of the electrode) can be improved.

9 is a graph showing current intensity distribution characteristics in the radial direction of the electrode when the ratio of the number density of protrusions at the electrode center portion and the edge portion is used as a parameter in the first embodiment. In the example of FIG. 9 , the electric field intensity distribution in the radial direction of the susceptor 12 is shown by assuming that the radius of the susceptor 12 is 150 mm. Here, the ratio Ne/Nc of the number density Nc of the protrusions 70 at the center of the electrode to the number density Ne of the protrusions 70 at the edge of the electrode is changed to 1 (times), 2 (times), 4 (times), 6 (times), 8 (times). The larger the ratio Ne/Nc is, the more the uniformity of the electric field intensity is improved, and thus the uniformity of the plasma density is improved.

Among other properties of the protrusion 70, the size is particularly important. If the height of the protrusion 70 is too small, more precisely, if it is smaller than the skin depth δ, a part or most of the high-frequency current i passes directly under the protrusion 70 on the main surface of the susceptor 12 . Therefore, for this reason, the high-frequency electric field supplied from the convex portion 70 to the plasma PZ is weakened. Here, the surface layer depth δ is a factor that the amplitude of the high-frequency current flowing through the surface layer of the conductor is attenuated by 1/e at the depth δ, and is given by the following formula (1):

δ＝(2/ωσμ) ^1/2 ………(1)

In the formula, ω=2πf (f: frequency), σ: electrical conductivity, μ: magnetic permeability.

8 is a characteristic diagram showing an attenuation characteristic in the depth direction of an electromagnetic wave (high-frequency current) flowing through a conductor. As shown in FIG. 8, due to the skin effect, the amplitude of the electromagnetic wave (high-frequency current) flowing through the surface layer of the conductor is attenuated in the depth direction of the conductor to about 5% at a depth three times the surface layer depth δ . Therefore, by setting the height of the convex portion 70 to be more than three times the surface layer depth δ, most of the high-frequency current i (about 95%) flows into the convex portion 70, and it is possible to efficiently transfer from the convex portion 70 to the convex portion 70. Plasma PZ emits high-frequency power. For example, when the material of the base 12 and the protrusion 70 is aluminum, and the frequency of the high-frequency power supply 32 is 100 MHz, the surface depth δ is 8 μm. Therefore, it is preferable to set the height of the convex portion 70 to 24 μm or more.

The width dimension of the protrusion 70, especially the width dimension in the electrode radial direction is also important. In order to allow the high-frequency current i to flow sufficiently into the top surface of the protrusion 70, it is only necessary that the width dimension in the radial direction of the electrode be large. The width dimension can be set to be three times or more the surface layer depth δ, and is preferably set within a range of 30 μm to 500 μm at a frequency of 100 MHz.

The distance interval between the convex portions 70 may be selected so as to optimize the impedance ratio Z _12a /Z ₇₀ between the convex portions 70 and the bottom surface portion 12a. The interval is preferably set within a range of 100 μm to 1 mm at, for example, 100 MHz.

10 is a partial longitudinal sectional view showing a structure in which an electrostatic chuck is integrally provided on a susceptor according to the first embodiment. As shown in FIG. 10 , the lower insulating film 40 b of the electrostatic chuck 40 is formed on the principal surface of the susceptor 12 , more precisely, on the convex portion 70 and the dielectric body 72 . The electrode film 40a is formed on the upper surface of the lower insulating film 40b, and further, the upper insulating film 40c is formed on the upper surface of the electrode film 40a.

FIG. 11 is a graph showing the impedance ratio characteristics of a convex portion and a bottom portion in the base structure with an electrostatic chuck shown in FIG. 10 . The parameter on the horizontal axis in FIG. 11 is the ratio S _12a /S ₇₀ of the total area S ₇₀ of the protrusions 70 (more precisely, the top surfaces of the protrusions) on the main surface of the base 12 to the total area S _12a of the bottom surface 12a. The vertical axis of FIG. 11 shows the ratio D2/D1 of the distance (D1) from the top surface of the protrusion 70 to the electrode film 40a to the distance (D2) from the base bottom surface 12a to the electrode film 40a. The function value in FIG. 11 shows the ratio Z 12a /Z ₇₀ of the impedance Z ₇₀ of the convex portion _on the main surface of the susceptor 12 to the impedance Z _12a of the bottom portion 12a.

In the laminated structure shown in FIG. 10, the film thickness D1 of the lower insulating film 40b of the electrostatic chuck 40 is important. As long as other conditions permit, it is preferable to make the film thickness D1 relatively small. As shown in FIG. 11 , the larger D2/D1 is, the larger Z _12a /Z ₇₀ can be. According to FIG. 11, the ratio D2/D1 is preferably selected to be a value of 2 (times) or more.

In addition, the impedance ratio Z _12a /Z ₇₀ (the function value in FIG. 11 ) can also be increased by reducing the ratio S _12a /S ₇₀ , that is, by increasing the occupied area ratio of the convex portion 70 . As described above, the larger the impedance ratio Z _12a /Z ₇₀ , the higher the high-frequency power supply rate from the convex portion 70 to the plasma PZ can be. According to FIG. 11 , the ratio S _12a /S ₇₀ is preferably selected to be 4 (times) or less.

12A to 12F are diagrams illustrating a method of manufacturing the base structure with an electrostatic chuck shown in FIG. 10 in order of steps.

First, as shown in FIG. 12A , on the main surface of the base main body (electrode substrate) 12 made of, for example, aluminum, a mask 74 made of, for example, resin having an opening 74 a corresponding to the protrusion 70 is covered. . In this mask 74 , the planar shape and planar size of the opening 74 a define the planar shape and planar size of the protrusion 70 . The depth of the opening 74a defines the height dimension of the protrusion 70 (D2-D1: 150 μm, for example).

Next, as shown in FIG. 12B , the material of the protrusion 70 , such as aluminum (Al), is sprayed from the upper surface of the mask 74 onto the entire main surface of the susceptor body 12 . Accordingly, the opening 74 a of the mask 74 is filled with aluminum up to the upper surface of the mask.

Next, the mask 74 is removed from the main surface of the susceptor body 12 by, for example, dissolving with a chemical solution. Thus, as shown in FIG. 12C , a plurality of protrusions 70 of a prescribed size are discretely left in a prescribed distribution pattern on the main surface of the base body 12 .

Next, as shown in FIG. 12D , a dielectric material such as aluminum oxide (Al ₂ O ₃ ) is sprayed on the entire main surface of the base body 12 . Accordingly, the dielectric film ( 72 , 40 b ) is formed with a film thickness reaching a predetermined height ( D1 : eg, 50 μm) from the top surface of the protrusion 70 .

Next, as shown in FIG. 12E , the material of the electrode film 40 a of the electrostatic chuck 40 , such as tungsten (W), is sprayed over the entire main surface of the susceptor body 12 on the upper surface of the dielectric film 40 b. Thus, an electrode film 40a having a predetermined thickness (D3: eg, 50 μm) is formed.

Next, as shown in FIG. 12F , a dielectric material such as aluminum oxide is sprayed on the electrode film 40 a over the entire main surface of the susceptor body 12 . Accordingly, the upper insulating film 40 c of the electrostatic chuck 40 is formed to a predetermined thickness ( D4 : 200 μm, for example).

In this embodiment, on the main surface of the susceptor main body 12, the dielectric body 72 for filling the periphery of the convex portion 70 (covering the bottom portion 12a) and the structure of the electrostatic chuck 40 can be simultaneously formed in one coating process. part of the lower insulating film 40b.

Although the base 12 of the above-mentioned embodiment is provided with the cylindrical convex part 70 on the main surface, the convex part 70 can be given arbitrary shape in the convex part 70. FIG. 13 is a diagram showing a modified example of the base structure according to the first embodiment. In a modified example shown in FIG. 13 , a plurality of annular protrusions 70 are concentrically arranged. That is to say, also in the susceptor structure of FIG. 13 , when the high-frequency current flows from the electrode edge to the center, the high-frequency current is efficiently emitted to the plasma PZ side from the convex portion 70 having lower impedance than the bottom portion 12a. frequency power. The area density of the protrusions 70 has a distribution characteristic that gradually increases from the center of the electrode to the edge of the electrode. Therefore, the uniformity of the electric field intensity in the radial direction of the electrode can be improved, and further the uniformity of the plasma density can be realized.

14 is a longitudinal sectional view showing a configuration example in which the electrode protrusion structure according to the first embodiment is applied to the upper electrode. In other words, as in the above-mentioned embodiment, the configuration in which a plurality of protrusions 70 functioning as small electrodes are discretely provided on the main surface, as shown in FIG. 14, can also be applied to the opposing electrode, that is, the upper part electrode.

In the configuration example of FIG. 14 , a convex portion 70 is arranged on the main surface (the lower surface, that is, the surface on the side of the plasma generation space) of the electrode plate 56 of the shower head 38, and around the convex portion 70 (the bottom surface 56b above) the dielectric body 72 is arranged. The gas vent hole 56a may be arranged to penetrate the convex portion 70 in the vertical direction. According to this configuration, the upper electrode 38 is mainly fed by the high-frequency current from the plasma PZ through the convex portion 70 . Therefore, in the upper electrode 38, by appropriately selecting the properties of the protrusions 70, the uniformity of the plasma density can be further improved. For example, the area density of the protrusions 70 may be formed to have a distribution characteristic that gradually increases from the center of the electrode to the edge of the electrode.

15, FIG. 16 and FIG. 17 are respectively plan views showing an electrode structure (base 12) according to a second embodiment of the present invention, showing a partial longitudinal sectional view of the structure, and showing the number density distribution of recesses in the structure. A diagram of an example of a property. On the main surface of the base 12, a plurality of cylindrical recesses 80 of a fixed size are discretely arranged. Since these concave portions 80 face the opposite electrode side, that is, the plasma PZ side, they are electrically connected to the plasma PZ with higher impedance than the top surface portion 12 a of the main surface. Therefore, the high-frequency power moved by the high-frequency current i flowing in the surface layer of the main surface of the susceptor 12 is mainly emitted from the top surface portion 12 a to the plasma PZ.

Among them, as shown in FIG. 16 , it is preferable that a dielectric body 82 is arranged in the concave portion 80 . Therefore, the impedance ratio Z ₈₀ /Z _12a between the concave portion 80 and the top surface portion 12a can be increased on the main surface of the base 12 . That is, the ratio of high-frequency power applied to the plasma PZ from the top surface portion 12a can be increased.

Thus, in the present embodiment, the plurality of recesses 80 discretely provided on the main surface of the susceptor 12 each function as an electrode mask for suppressing the supply of high-frequency power to the plasma PZ. By appropriately selecting the properties (shape, size, spacing, density, etc.) of the recesses 80 , the high-frequency power supply characteristics in the susceptor 12 can be controlled to desired characteristics.

For example, as shown in FIG. 17 , the number density of the recesses 80 may be formed into a distribution characteristic that gradually decreases from the center of the electrode toward the edge of the electrode. Therefore, the uniformity (in particular, uniformity in the radial direction) of the high-frequency power or high-frequency electric field applied to the plasma PZ from the susceptor 12 can be improved, thereby improving the uniformity of the plasma density. Other attributes of the concave portion 80 can basically be handled in the same manner as the convex portion 70 in the first embodiment. For example, the depth and width of the concave portion 80 can be set to be three times or more the surface depth δ.

18A to 18F are diagrams showing, in order of steps, a method of manufacturing a structure in which an electrostatic chuck is integrally provided on an electrode structure according to the second embodiment.

First, as shown in FIG. 18A , on the main surface of the base body (electrode substrate) 12 made of, for example, aluminum, a mask 84 made of, for example, resin having openings 84 a corresponding to recesses 80 is covered. In this mask 84 , the planar shape and planar size of the opening 84 a define the planar shape and planar size of the recess 80 .

Next, as shown in FIG. 18B , solid particles (such as dry ice pellets) or fluid (high-pressure water jets) are sprayed from above the mask 84 to the entire main surface of the susceptor main body 12 by shot blasting. Thereby, the material (aluminum) inside the opening portion 84a is physically removed, and the concave portion 80 of a desired depth is formed there.

Next, the mask 84 is removed from the main surface of the susceptor main body 12 . Therefore, as shown in FIG. 18C , a plurality of recesses 80 of a prescribed size are discretely left in a prescribed distribution pattern on the main surface of the base body 12 .

Next, as shown in FIG. 18D , a dielectric material such as aluminum oxide (Al ₂ O ₃ ) is sprayed on the entire main surface of the base body 12 . Accordingly, the dielectric film (82, 40b) is formed with a film thickness reaching a predetermined height from the susceptor top surface portion 12a.

Next, as shown in FIG. 18E , the electrode material of the electrostatic chuck 40 , for example, tungsten (W), is sprayed on the upper surface of the dielectric film 40 b over the entire main surface of the susceptor body 12 . Thus, the electrode film 40a having a predetermined thickness is formed.

Next, as shown in FIG. 18F , a dielectric material such as aluminum oxide is sprayed over the electrode film 40 a across the entire main surface of the susceptor body 12 . Thus, the upper insulating film 40c is formed to a predetermined thickness.

In this embodiment, the dielectric body 82 for filling the recess 80 and the lower insulating film 40b constituting a part of the electrostatic chuck 40 can be simultaneously formed on the main surface of the susceptor body 12 in one coating process.

In addition, in this embodiment, although illustration is omitted, a configuration in which a plurality of concave portions functioning as electrode mask portions are discretely provided on the main surface of the electrode may be applied to the counter electrode, that is, the upper portion. electrode 38. Therefore, it is also possible to provide the convex portion 70 on the base 12 side and the concave portion 80 on the upper electrode 38 side, or to provide the concave portion 80 on the base 12 side and the convex portion 70 on the upper electrode 38 side. composition.

19 and 20 are plan views showing a lower electrode structure and an upper electrode structure according to a third embodiment, respectively. That is, FIG. 19 shows a configuration example in which the third embodiment is applied to the base 12 . FIG. 20 shows a configuration example in which the third embodiment is applied to the upper electrode 38 (more precisely, the electrode plate 56).

In this embodiment, a dielectric film or a dielectric layer 90 is disposed on the main surface of the electrode, that is, the surface on the side of the plasma generation space (the lower surface in the case of the upper electrode 38, and the upper surface in the case of the susceptor 12). . The thickness of the dielectric film 90 at the center of the electrode is larger than the thickness of the dielectric film 90 at the edge of the electrode. The surface of the dielectric film 90 (the surface on the side of the plasma generation space) is formed substantially in the same plane. The dielectric film or dielectric layer 90 can be formed, for example, by spraying ceramics made of aluminum oxide (Al ₂ O ₃ ), for example, on an electrode substrate made of aluminum.

According to this electrode structure, the impedance on the center side of the plasma PZ electrode is relatively high and the impedance on the edge side of the electrode is relatively low. Therefore, the high-frequency electric field on the side of the electrode edge is strengthened, and on the other hand, the high-frequency electric field on the side of the electrode center is weakened. As a result, the uniformity of electric field intensity or plasma density is improved. In particular, in the configuration example of FIG. 19, if the current returning from the back side of the electrode 12 to the main surface side due to the skin effect flows into the dielectric film 90, it is easy to flow from the thin film part (dielectric film 90). The thin part of the electric layer) leaks to the plasma side. Therefore, emission of high-frequency power and plasma density on the side of the electrode edge can be enhanced.

FIG. 21 is a diagram showing an example of the parallel plate electrode structure in the third embodiment. FIG. 22 is a graph showing the electric field intensity distribution in the radial direction between electrodes with the film thickness at the center of the upper electrode as a parameter in the parallel plate electrode structure of FIG. 21 . One of the important parameters in the film thickness distribution characteristics of the dielectric film 90 is the film thickness at the center of the electrode. As shown in FIG. 21, in the parallel plate electrode structure provided with a disk-shaped dielectric film 90, the electric field intensity distribution in the radial direction between the electrodes is obtained by simulation using the film thickness Dc at the center of the upper electrode 38 as a parameter. .

In this simulation, a semiconductor wafer with a diameter of 300 mm is assumed as the substrate to be processed. It is assumed that the upper electrode 38 is aluminum, the dielectric film 90 is aluminum oxide (Al ₂ O ₃ ), and the lower electrode 12 is aluminum. As shown in FIG. 22 , in the range of 0.5 mm to 10 mm, the in-plane uniformity of the electric field intensity can be improved as the film thickness at the center of the electrode increases, and the film thickness of 8 mm to 10 mm is particularly good. Here, the position of "0" on the horizontal axis in FIG. 22 represents the position of the center point of the electrode.

In addition, the profile in which the thickness of the dielectric film 90 decreases from the center of the electrode to the edge of the electrode is also important. 23A to 23D are diagrams showing more specific examples of the film thickness profile of the dielectric film of the upper electrode in the third embodiment. 24A and 24B are graphs showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained from the example and the ideal profile of FIGS. 23A to 23D , respectively.

In the embodiment [1] shown in FIG. 23A, the film thickness D of the dielectric film 90 is set at  (diameter) 0 to 30 mm, D=9 mm (flat, that is, constant), and at  At 30~160mm, D=8mm (flat), at 160~254mm, D=8~3mm (inclined). In the embodiment [2] shown in FIG. 23B, D=9mm (flat) at 0~30mm, D=8mm (flat) at 30~80mm, and D=8mm (flat) at 80~160mm At the place, D=8~3mm (tilt). In the embodiment [3] shown in FIG. 23C, D=9mm (flat) at 0~30mm, D=8mm (flat) at 30~160mm, and D=8mm (flat) at 160~330mm At the place, D=8~3mm (tilt).

In Fig. 23D, outlines of the above-mentioned embodiments [1], [2], and [3] are schematically shown in curves. At the same time, although the cross-sectional shape is not shown in the figure, it also shows the embodiment [4] which is set to D=0.5mm (flat) at 0-150mm, and further shows the ideal profile. Here, the ideal profile means that it is set at 0 to 300 mm, and D=9 to 0 mm (inclined type).

As shown in FIGS. 24A and 24B , the electric field intensity distribution characteristics produced by the ideal profile are optimal in terms of in-plane uniformity. Among the examples [1], [2], [3], and [4], the examples [1] and [3] which are close to the ideal profile are all excellent in in-plane uniformity.

Among them, since the upper electrode 38 (electrode plate 56 ) receives a high-frequency current from the diffused plasma PZ, the edge portion can be extended radially outward so that the diameter is larger than the diameter of the substrate to be processed. Here, on the main surface of the upper electrode 38 , a thermally sprayed coating film 92 having a film thickness of, for example, 20 μm may be formed on the periphery of the dielectric film 90 or on the radially outer portion. Although illustration is omitted, a similar thermal spray coating 92 may also be formed on the inner wall surface of the chamber 10 . As the thermal spray coating 92, for example, Al ₂ O ₃ , Y ₂ O ₃ or the like can be used. In addition, the respective surfaces of the dielectric film 90 and the sprayed coating film 92 , that is, the surfaces exposed to plasma are formed to be substantially coplanar.

25A to 25D are diagrams showing another more specific example of the film thickness profile of the dielectric film of the upper electrode in the third embodiment. 26A and 26B are graphs showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of FIGS. 25A to 25D .

In Example [5] shown in FIG. 25A , the film thickness D of the dielectric film 90 is set to be within a range of 0 to 250 mm, and D=5 mm (flat). In the embodiment [6] of FIG. 25B, D=9 mm (flat) at 0-30 mm, and D=8-3 mm (inclined) at 30-250 mm. In the embodiment [7] of FIG. 25C, D=9mm (flat) at 0-30mm, and D=5-3mm (inclined) at 30-250mm. The profiles of the embodiments [5], [6] and [7] are schematically shown as curves in Fig. 23D.

As shown in Fig. 26A and Fig. 26B, among these embodiments [5], [6], [7], the embodiment [6] which is closest to the ideal profile is the best in terms of in-plane uniformity. In addition, Example [5] also has sufficient practicability. That is to say, even if the profile in which the film thickness D of the dielectric film 90 decreases almost linearly or obliquely from the center of the electrode toward the edge of the electrode as in Example [6], it is possible to obtain a profile close to an arcuate shape. The in-plane uniformity of the ideal profile. In addition, even if the thickness D of the dielectric film 90 is substantially constant (flat) from the center of the electrode to the edge of the electrode as in Example [5], practical in-plane uniformity can be obtained.

27A to 27C are diagrams showing other more specific examples of the film thickness and film quality profile of the dielectric film of the upper electrode in the third embodiment. 28A and 28B are graphs showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of FIGS. 27A to 27C .

In the embodiment [8] shown in FIG. 27A , the film thickness D of the dielectric film 90 is set to be D = 9 mm (flat) at  0 to 30 mm, and D = 9 mm (flat) at  30 to 250 mm. = 8 ~ 3mm (inclined). In the embodiment [9] of FIG. 27B, D=5mm (flat) at 0-30mm, and D=5-3mm (inclined) at 30-250mm. In Fig. 27C, the profiles of the embodiments [8] and [9] are schematically shown as curves.

Here, using the dielectric constant ε as a parameter, the embodiment [8] is divided into: the embodiment (8)-A in which the material of the dielectric film 90 is aluminum oxide (Al ₂ O ₃ ) with a dielectric constant ε=8.5, And be the embodiment [8]-B of silicon oxide (SiO ₂ ) of ε=3.5.In addition, embodiment [9] is also divided into: the embodiment [8] of aluminum oxide (Al ₂ O ₃ ) of ε=8.5 9)-A, and the embodiment [9]-B of silicon oxide (SiO ₂ ) with ε=3.5.

As shown in Fig. 28A and Fig. 28B, between the embodiments [8]-A and [9]-A of ε=8.5, the electric field intensity E of the [8]-A side with the larger film thickness Dc at the center of the electrode The in-plane uniformity is better than that of [9]-A. Between the embodiments [8]-B and [9]-B of ε=3.5, the in-plane uniformity of the electric field intensity E of [9]-B with the smaller film thickness Dc at the center of the electrode is greater than that of [8]-B better.

FIG. 29 is a graph showing the correlation between the dielectric constant ε of the dielectric film 90 and the film thickness Dc at the central portion that gives practically sufficient in-plane uniformity, created based on the data points in FIGS. 28A and 28B . As shown in this graph, it is only necessary to set the film thickness Dc of the central portion according to the dielectric constant ε of the dielectric film 90 .

30A and 30B are diagrams comparing Example A and Comparative Example B in which the third embodiment is applied to the upper electrode with respect to the etching rate distribution characteristics of organic film etching. Here, the etching rate distribution characteristic (X direction, Y direction) of the organic film etching using the plasma etching apparatus (FIG. 1) of embodiment is shown. In Example A, the dielectric film 90 according to the third embodiment is provided on the upper electrode 38 . In Comparative Example B, the dielectric film 90 was not provided on the upper electrode 38 . Among them, Example A corresponds to the above-mentioned Example [1]. The main etching conditions are as follows:

Wafer diameter: 300mm

Etching gas: _NH3

Gas flow: 245sccm

Gas pressure: 30mTorr

RF power: lower = 2.4kW

Wafer inner pressure (center part/edge part): 20/30Torr (He gas)

Temperature (chamber side wall/upper electrode/lower electrode): 60/60/20°C.

It can be clearly seen from FIG. 30A and FIG. 30B that, corresponding to the distribution characteristics of the electric field intensity, the in-plane uniformity of the etching rate is clearly superior to that of the comparative example B in the embodiment A.

31A and 31B are diagrams comparing Example A and Comparative Example B in which the third embodiment is applied to the structure of the lower electrode. In the embodiment A of FIG. 31A, for a semiconductor wafer W with an aperture of 300 mm, the film thickness D of the dielectric film 90 at the base 12 is set to 4 mm at the center of the electrode, and 4 mm at the edge of the electrode. It becomes 200 μm. In Comparative Example B in FIG. 31B , a dielectric film 94 with a uniform film thickness of 0.5 mm is provided on the upper surface of the susceptor 12 . The material of both the dielectric films 90 and 94 may be aluminum oxide (Al ₂ O ₃ ).

FIGS. 32A and 32B are graphs comparing the example A of FIG. 31A and the comparative example B of FIG. 31B with respect to the etching rate distribution characteristics of organic film etching. Here, the etching rate distribution characteristic (X direction, Y direction) of the organic film etching using the plasma etching apparatus (FIG. 1) of embodiment is shown. The etching conditions are the same as those in FIGS. 30A and 30B.

As shown in FIGS. 32A and 32B , in the case of the susceptor (lower electrode) 12 , the in-plane uniformity of the etching rate of Example A is significantly superior to that of Comparative Example B. In addition, the etching rate itself was about 10% higher in Example A than in Comparative Example. Here, in Example A, the film thickness D of the dielectric film 90 at the center of the electrode was set to 4 mm, but the same effect can be obtained even if it is as large as about 9 mm.

33A and 33B are partial cross-sectional views showing an example of an upper electrode structure according to another embodiment of the present invention. This embodiment is particularly suitable for use in a configuration in which the dielectric film 90 is provided on the upper electrode 38 .

As shown in FIGS. 33A and 33B , on the main surface of the upper electrode 38 , a conductive shield plate 100 covering a part of the dielectric film 90 (generally around the edge portion) is provided. The shield plate 100 is preferably made of, for example, an aluminum plate whose surface has been anodized ( 92 ), and is detachably, that is, replaceably, attached to the upper electrode 38 with screws 102 . In the center portion of the shield plate 100 , an opening 100 a of a desired diameter θ exposing at least the center portion is formed coaxially with the dielectric film 90 . The thickness of the shielding plate 100 can be selected to be, for example, about 5 mm.

As a specific example, in Example A shown in FIG. 33A, θ=200 mm is set, and in Example B shown in FIG. 33B, θ=150 mm is set. In either of the two embodiments, the dielectric film 90 is formed into a disc shape with a diameter of 250 mm, and its film thickness profile is set to D=8 mm (flat) at 0 to 160 mm, and at  At 160-250mm, D=8-3mm (inclined).

Fig. 34 is a graph showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of Figs. 33A and 33B. As shown in FIG. 34 , by covering a part of the dielectric film 90 with the conductive shield plate 100 , the effect of the dielectric film 90 in the covered area, that is, the effect of reducing the electric field intensity can be reduced or eliminated. Therefore, by changing the diameter θ of the opening 100a of the shielding plate 100 (by replacing the parts of the shielding plate 100), the electric field intensity distribution characteristics between the two electrodes 12 and 38 can be adjusted.

35A to 35C are partial cross-sectional views showing examples, comparative examples, and reference examples, respectively, of upper electrode structures according to yet another embodiment of the present invention. This embodiment is also particularly suitable for the configuration in which the dielectric film 90 is provided on the upper electrode 38 .

As shown in FIG. 35A , in the present embodiment, on the main surface of the upper electrode 38 , from a radial position (position of an aperture ω) larger than that of the dielectric film 90 , the outer electrode portion 38 f faces toward the base. The side of 12 or the side of the plasma generation space protrudes by a desired protrusion amount (protrusion amount). Here, the electrode gap Gf at the electrode portion 38 f is smaller than the electrode gap Go at the dielectric film 90 .

In Example A shown in FIG. 35A , the diameter of the dielectric film 90 is set to 80 mm, and the film thickness profile is set to be D=3 mm (flat) at 0 to 60 mm, and D=3 mm (flat) at 60 to 60 mm. At 80mm, D=3~1mm (inclined), and ω=260mm. Now, the electrode gap Go=40mm at the dielectric film 90 is set to h=10mm, and the electrode gap Gf at the outer electrode extension portion 38f is formed to be Gf=30mm. Here, the protruding stepped portion of the outer electrode protruding portion 38f is inclined by about 60°. The angle of inclination can be chosen to be any size.

In FIG. 35B , as a comparative example B, a configuration in which the upper electrode 38 is provided with a dielectric film 90 having the same diameter and the same thickness profile as that of Example A is shown without providing the projecting portion 38 f. In addition, in FIG. 35C , as a reference example C, a configuration in which neither the overhang portion 38 f nor the dielectric film 90 is provided on the upper electrode 38 is shown. Any electrode gap in FIG. 35B and FIG. 35C is constant in the radial direction, which is Go=40mm.

FIG. 36 is a graph showing radial electric field intensity distribution characteristics between electrodes obtained from Example A, Comparative Example B, and Reference Example C of FIGS. 35A to 35C . As shown in FIG. 36, in Example A, by providing the projecting portion 38f on the radially outer side of the dielectric film 90, the region near the edge portion of the semiconductor wafer W (in the illustrated example, away from The area with a central radius of about 90 mm to 150 mm) can control or adjust the distribution characteristics of the electric field intensity in the direction of increasing the electric field intensity E. The addition and subtraction of the control of the electric field intensity distribution caused by the extension 38f can be adjusted by the extension h, preferably h=10 mm or more.

The position (the value of the diameter ω) of the protruding step portion of the outer electrode protruding portion 38f can be selected arbitrarily. 37A to 37C are partial cross-sectional views showing other two examples and a comparative example of the structure of the upper electrode, respectively.

In the embodiment of FIG. 37A, it is set to ω=350mm, and in the embodiment of FIG. 37B, it is set to ω=400mm. In addition, in either of the two examples A and B, the film thickness profile of the dielectric film 90 is D=8 mm (flat) at 0 to 80 mm, and D=8 to 3 mm at 80 to 160 mm. (tilt). The electrode gap Go=30mm at the dielectric film 90 is set to h=10mm, and the electrode gap Gf at the outer electrode projecting portion 38f is Gf=20mm. In addition, the protruding stepped portion of the outer electrode protruding portion 38f is inclined at about 60°.

In FIG. 37C , as a comparative example C, a configuration is shown in which the upper electrode 38 is provided with a dielectric film 90 having the same diameter and thickness profile as those of Examples A and B without providing the overhanging portion 38f. The electrode gap is constant in the radial direction and is Go=30mm.

38 is a graph showing the distribution characteristics of the etching rate (normalized value) of oxide film etching obtained from Examples A, B and Comparative Example C of FIGS. 37A to 37C . As the main etching conditions, the used wafer diameter is 300 mm, the pressure is 15 mTorr, and the processing gas is C ₄ F ₆ /Ar/O ₂ /CO. In Examples A and B of FIGS. 35A and 35B , on the main surface of the upper electrode 38 , a protrusion step portion of the outer electrode protrusion 38f is provided on the radially outer side of the edge of the semiconductor wafer W. As shown in FIG. 38, in this configuration, the closer the position of the protruding step portion is to the wafer (the smaller ω is), the more the area near the wafer (for example, the area with a radius of about 70 mm to 150 mm from the center in the figure) is used. The effect of increasing the etching rate (that is, electric field strength or plasma electron density) is greater.

In the embodiment described with reference to FIGS. 35A to 38 , as described above, the electrode portion on the radially outer side of the dielectric film 90 on the main surface of the upper electrode 38 is configured to protrude into the plasma generation space. Conversely, as shown in FIG. 39A , the dielectric film 90 may protrude from the main surface of the upper electrode 38 by a desired protrusion amount (protrusion amount) k into the plasma generation space. 39A to 39C are partial cross-sectional views showing an example, a comparative example, and a reference example, respectively, of an upper electrode structure according to yet another embodiment of the present invention.

In Example A of FIG. 39A , the diameter of the dielectric film 90 is 250 mm, and its film thickness profile is D=8 mm (flat) at 0 to 160 mm, and D=8 to 8 at 160 to 250 mm. 3mm (tilted). The inclined surface 90 a was set to k=5 mm toward the base 12 side, and the electrode gap Gm at the dielectric film 90 was set to Gm=35 mm. The radially outer electrode portion of the dielectric film 90 is a flat surface, and the electrode gap Go is Go=40 mm.

In FIG. 39B, as a comparative example B, a dielectric film 90 having the same film thickness profile as that of Example A is not protruded on the upper electrode 38, but is provided in the opposite direction (inclined surface 90a toward the back side). constitute. In addition, in FIG. 39C , as a reference example C, a configuration in which the dielectric film 90 is not provided on the upper electrode 38 is shown. Any electrode gap in Figure 39B and Figure 39C is constant in the radial direction, Go=40mm.

FIG. 40 is a graph showing radial electric field intensity distribution characteristics between electrodes obtained from Example A, Comparative Example B, and Reference Example C of FIGS. 39A to 39C . As shown in FIG. 40, by extending the dielectric film 90 as in Example A, compared with Comparative Example B which does not do so, at each position in the radial direction, the electric field intensity E is increased. The electric field intensity distribution characteristics can be controlled or adjusted. The addition and subtraction of the electric field intensity distribution control caused by the protrusion 38 can be adjusted by the protrusion k, preferably k=5mm or more.

FIG. 41 is a partial cross-sectional view showing the structure of an upper electrode according to a modified example of the embodiment shown in FIGS. 35A to 38 . As shown in FIG. 41 , on the main surface of the upper electrode 38 , the projecting portion 38 f is provided on the radially outer side of the dielectric film 90 . In this way, the edge portion of the dielectric film 90 may be connected to the outer electrode extension portion 38f, or the edge portion of the dielectric film 90 may be extended together with the outer electrode extension portion 38f.

42A to 42D are partial cross-sectional views showing the structure of the upper electrode according to still another embodiment of the present invention. As shown in FIGS. 42A to 42D , in this embodiment, the dielectric film 90 provided on the main surface of the upper electrode 38 is formed of a hollow dielectric body having a cavity 104 inside, for example, hollow ceramics. In this embodiment, the hollow dielectric body 90 preferably has a profile in which the thickness on the radial center side is greater than the thickness on the edge side.

The cavity 104 of the hollow dielectric body 90 is filled with a fluid dielectric substance NZ in a desired amount. The dielectric fluid NZ in the cavity 104 constitutes a part of the dielectric body 90 according to its occupied volume. Such a dielectric fluid NZ may be a powder, but generally, an organic solvent (for example, heat transfer liquid (Galdeso)) is preferable.

As a port for allowing the dielectric fluid NZ to enter and exit the cavity 104, for example, a plurality of pipes 106 and 108 may be connected to different parts of the cavity 104 (for example, the center and the edge) from the inner side of the electrode 38 . When dielectric fluid NZ enters cavity 104 of hollow dielectric body 90, as shown in FIG. Air. When reducing the amount of the dielectric fluid NZ in the cavity 104, as shown in FIG. 42C, the dielectric fluid in the cavity 104 can be released from the other tube 106 while feeding air from one tube 106. NZ will do.

Fig. 43 is a partial cross-sectional view showing a specific example of the embodiment shown in Figs. 42A to 42D. In this embodiment, the entire hollow dielectric body 90 is formed as a disc with a diameter of 210mm, and its thickness is D=6mm (flat) at 0-60mm, and D=6-3mm (inclined) at 60-210mm. . The cavity 104 of the hollow dielectric body 90 has a thickness α of 2 mm and a diameter β of 180 mm.

Fig. 44 is a graph showing the electric field intensity distribution characteristics in the radial direction between electrodes obtained in the example of Fig. 43 . In FIG. 44, the distribution characteristic A of ε=1 is obtained in the state of FIG. 42A, that is, the state in which the cavities 104 of the hollow dielectric body 90 are completely empty and filled with air. In addition, the distribution characteristic B of ε=2.5 is obtained in the state of FIG. 42C , that is, the state in which the cavities 104 of the hollow dielectric body 90 are completely filled with the heat transfer liquid. Any characteristic between the two characteristics A and B can be obtained by adjusting the amount of the heat transfer fluid entering the cavity 104 .

In this way, in this embodiment, by changing the type and amount of the dielectric material NZ that enters the cavity 104 of the hollow dielectric body 90, the overall dielectric constant or dielectric property of the dielectric body 90 can be variably controlled. impedance.

45A to 45D are partial cross-sectional views showing the structure of an upper electrode according to a modified example of the embodiment shown in FIGS. 42A to 42D .

In the modified example of FIG. 45A , the surface of dielectric body 90 is formed by ceramic plate 91 , and the wall facing ceramic plate 91 is formed by the base material (aluminum) of the upper electrode in inner cavity 104 . That is, a recess 38 c corresponding to the shape of the dielectric body 90 is formed on the main surface of the upper electrode 38 , and the recess 38 c is covered with the ceramic plate 91 . In order to seal the outer periphery of the ceramic plate 91, it is preferable to provide a sealing member 110 such as an O-ring, for example. In this case, the shape of the recessed portion 38c or the cavity 104 is important, and it is still preferable to have a shape in which the thickness of the center portion is larger than that of the edge portion.

In the modified example of FIG. 45B, C, in the hollow dielectric body 90, the space or cavity 104 allocated to the dielectric fluid NZ is limited or localized to a specific region. For example, as shown in FIG. 45B , the space of the cavity 104 is localized in the central portion region of the dielectric body 90 . Alternatively, as shown in FIG. 45C, by making the thickness of the ceramic plate 91 vary in the radial direction (gradually decreasing from the center portion to the edge portion), the space of the cavity 104 can be relatively localized in the dielectric body 90. Peripheral area. In this way, in the hollow dielectric body 90 , the spaces of the cavities 104 are defined in a desired region or shape, so that various proposals can be made for the dielectric constant adjustment function of the dielectric fluid NZ.

In the modified example of FIG. 45D , the cavity 104 in the hollow dielectric body 90 is divided into a plurality of chambers, and the entry and exit of the dielectric fluid NZ is controlled independently for each chamber. For example, as shown in FIG. 45 , the cavity 104 can be divided into a central chamber 104A and a peripheral chamber 104B by an annular partition wall 91a integrally formed on the ceramic plate 91.

Although the best embodiments of the present invention have been individually described above, it is also possible to combine electrode structures in different embodiments. For example, combining the electrode structure having the dielectric body 90 according to the above-mentioned third embodiment or the following embodiments with the electrode structure having the convex portion 70 according to the above-mentioned first embodiment or the electrode structure having the concave portion 80 according to the second embodiment. Combinations of electrode structures are also possible.

That is, the electrode structure according to the third embodiment or the following embodiments is applied to the susceptor 12, for example, as shown in FIG. 3) or the application of the electrode structure ( FIG. 15 , FIG. 16 ) according to the second embodiment described above is possible. In addition, the electrode structure according to the third embodiment or the following embodiments is applied to the upper electrode 38 as shown in FIG. 20, and the electrode structure according to the above-mentioned first embodiment ( FIGS. Application of the electrode structure ( FIG. 15 , FIG. 16 ) according to the second embodiment described above is also possible.

Of course, it is also possible to apply the electrode structure according to the first, second, third embodiment, or the following embodiments to both the upper electrode and the lower electrode. In addition, it is also possible to apply the electrode structure according to the first, second, third embodiments, or the following embodiments to only the upper electrode or the lower electrode, and use a conventional general electrode on the other electrode. .

In addition, the plasma etching apparatus ( FIG. 1 ) of the above-mentioned embodiment is a system in which one high-frequency power for plasma generation is applied to the susceptor 12 . However, although illustration is omitted, it is possible to apply the present invention to a system in which high-frequency power for plasma generation is applied to the upper electrode 38 side. In addition, it is possible to apply the present invention to a method of applying first and second high-frequency powers of different frequencies to the upper electrode 38 and the susceptor 12 (upper and lower high-frequency application method). In addition, it is also possible to apply the present invention to a method of superimposing first and second high-frequency powers having different frequencies on the susceptor 12 (lower two-frequency superimposed application method) and the like.

In a broad sense, the present invention can be applied to a plasma processing apparatus having at least one electrode in a depressurizable processing container. Furthermore, the present invention can also be applied to other plasma processing devices such as plasma CVD, plasma oxidation, plasma nitridation, and sputtering. In addition, the substrate to be processed in the present invention is not limited to a semiconductor wafer, and various substrates for flat panel displays, photomasks, CD substrates, printed substrates, etc. are also possible.

Industrial Applicability

If the plasma processing apparatus or the electrode plate for the plasma processing apparatus of the present invention is used, the uniformity of the plasma density can be efficiently achieved by the above-mentioned structure and function.

In addition, according to the electrode plate manufacturing method of the present invention, the structure in which the electrode plate is integrally provided with an electrostatic chuck for the plasma processing apparatus of the present invention can be efficiently produced.

Claims (44)

1. A plasma processing device is a plasma processing device for implementing plasma processing on a processed substrate, characterized in that it comprises: a decompressible processing container that accommodates the substrate to be processed; a first electrode disposed within the processing vessel; a supply system for supplying process gas into the process vessel; and an electric field forming system for generating plasma of the processing gas and forming a high-frequency electric field in the processing container, wherein, On the main surface of the first electrode, a plurality of protrusions protruding toward a space where the plasma is generated are discretely formed. 2. The plasma processing apparatus according to claim 1, characterized in that: High-frequency power for generating the plasma is supplied from the inside opposite to the main surface of the first electrode. 3. The plasma processing apparatus according to claim 1, characterized in that: The processing chamber further includes a second electrode parallel to the first electrode, and high-frequency power for generating the plasma is supplied from the back surface of the second electrode opposite to the main surface. . 4. The plasma processing apparatus as claimed in claim 1, characterized in that: On the main surface of the first electrode, the height of the protrusion and the width in the radial direction of the electrode are given by the following formula (1): δ＝(2/ωσμ) ^1/2 ... (1) more than three times the expressed surface depth δ, Where, ω=2πf (f: frequency), σ: electrical conductivity, μ: magnetic permeability. 5. The plasma processing apparatus according to claim 1, characterized in that: On the main surface of the first electrode, the area density of the protrusions is gradually increased from the center of the electrode to the edge of the electrode. 6. The plasma processing apparatus according to claim 1, characterized in that: On the main surface of the first electrode, the protrusions are formed in a size such that the number density of the protrusions gradually increases from the center of the electrode to the edge of the electrode. 7. The plasma processing apparatus according to claim 1, characterized in that: The convex portion is formed in a cylindrical shape. 8. The plasma processing apparatus according to claim 1, characterized in that: Each of the convex portions is formed in an annular shape, and the entirety thereof is arranged concentrically. 9. The plasma processing apparatus according to claim 1, characterized in that: A dielectric is provided on at least a portion other than the protrusion on the main surface of the first electrode. 10. A plasma processing device, which is a plasma processing device for performing plasma processing on a substrate to be processed, characterized in that it comprises: a decompressible processing container that accommodates the substrate to be processed; a first electrode disposed within the processing vessel; a supply system for supplying process gas into the process vessel; and an electric field forming system for generating plasma of the processing gas and forming a high-frequency electric field in the processing container, wherein, On the principal surface of the first electrode, a plurality of concave portions recessed toward a space where the plasma is generated are discretely formed. 11. The plasma processing apparatus according to claim 10, characterized in that: High-frequency power for generating the plasma is supplied from an inner surface on a side opposite to the main surface of the first electrode. 12. The plasma processing apparatus according to claim 10, characterized in that: The processing chamber further includes a second electrode parallel to the first electrode, and high-frequency power for generating the plasma is supplied from a back surface of the second electrode on a side opposite to the main surface. . 13. The plasma processing apparatus according to claim 10, characterized in that: On the main surface of the first electrode, the depth of the recess and the width in the radial direction of the electrode are given by the following formula (1): δ＝(2/ωσμ) ^1/2 ... (1) more than three times the expressed surface depth δ, Where, ω=2πf (f: frequency), σ: electrical conductivity, μ: magnetic permeability. 14. The plasma processing apparatus according to claim 10, characterized in that: On the main surface of the first electrode, the area density of the recesses is gradually increased from the center of the electrode to the edge of the electrode. 15. The plasma processing apparatus according to claim 10, characterized in that: On the main surface of the first electrode, the recesses are formed in a size such that the number density of the recesses gradually increases from the center of the electrode to the edge of the electrode. 16. The plasma processing apparatus according to claim 10, characterized in that: The concave portion is formed in a cylindrical shape. 17. The plasma processing apparatus according to claim 10, characterized in that: On the main surface of the first electrode, a dielectric is provided at least in the concave portion. 18. A plasma processing device, which is a plasma processing device for performing plasma processing on a substrate to be processed, characterized in that it comprises: a decompressible processing container that accommodates the substrate to be processed; a first electrode disposed within the processing vessel; a supply system for supplying process gas into the process container; and an electric field forming system for generating plasma of the processing gas and forming a high-frequency electric field in the processing container, wherein, A dielectric body is arranged on the main surface of the first electrode, and the thickness of the dielectric body on the center side of the first electrode is greater than the thickness of the dielectric body on the electrode edge side. 19. The plasma processing apparatus according to claim 18, characterized in that: High-frequency power for generating the plasma is supplied from an inner surface on a side opposite to the main surface of the first electrode. 20. The plasma processing apparatus according to claim 18, characterized in that: The processing chamber further includes a second electrode parallel to the first electrode, and high-frequency power for generating the plasma is supplied from a back surface of the second electrode on a side opposite to the main surface. . 21. The plasma processing apparatus according to claim 18, characterized in that: The thickness of the dielectric body at the first electrode gradually decreases from the center portion of the electrode to the edge portion of the electrode. 22. The plasma processing apparatus according to claim 21, characterized in that: The thickness of the dielectric body at the first electrode is arched and gradually decreases from the center of the electrode to the edge of the electrode. 23. The plasma processing apparatus according to claim 18, characterized in that: The thickness of the dielectric body at the first electrode is almost constant inside the first diameter including the central portion. 24. The plasma processing apparatus according to claim 23, characterized in that: There is a portion in which the thickness of the dielectric body at the first electrode decreases obliquely toward the edge of the electrode outside the first diameter. 25. The plasma processing apparatus according to claim 23, characterized in that: The thickness of the dielectric body at the first electrode is almost constant outside the first diameter and inside a second diameter larger than the first diameter. 26. The plasma processing apparatus according to claim 25, characterized in that: There is a portion in which the thickness of the dielectric body at the first electrode decreases obliquely toward the edge of the electrode at the outer side of the second diameter. 27. The plasma processing apparatus according to claim 18, characterized in that: The thickness of the dielectric body at the first electrode becomes minimum near a position facing an edge portion of the substrate to be processed. 28. The plasma processing apparatus according to claim 18, characterized in that: The thickness at the electrode center portion of the dielectric body is set to a value corresponding to the permittivity of the dielectric body. 29. The plasma processing apparatus according to claim 18, characterized in that: A conductive shield member covering a part of the dielectric body is further provided on the main surface of the first electrode. 30. The plasma processing apparatus according to claim 29, characterized in that: The shield member has an opening of a desired diameter exposing at least a central portion of the dielectric body. 31. The plasma processing apparatus according to claim 30, characterized in that: The shielding member is detachably mounted on the first electrode. 32. The plasma processing apparatus of claim 18, wherein: On the main surface of the first electrode, an outer electrode portion protrudes toward the plasma generation space by a desired protrusion from a position radially outward from the outer peripheral edge of the dielectric body by a desired distance. quantity. 33. The plasma processing apparatus according to claim 18, wherein: On the main surface of the first electrode, the dielectric body is protruded by a desired amount toward a space where the plasma is generated. 34. The plasma processing apparatus according to claim 18, wherein: On the main surface of the first electrode, a cavity is provided inside the dielectric body, and a fluid dielectric substance is filled in the cavity. 35. The plasma processing apparatus of claim 34, wherein: At least two openings for allowing the dielectric substance to enter and exit the cavity are provided on the first electrode. 36. The plasma processing apparatus according to claim 34, wherein: The dielectric substance is an organic solvent. 37. The plasma processing apparatus according to claim 34, wherein: At the main surface of the first electrode, at least a surface of the dielectric body is composed of a solid. 38. An electrode plate for generating plasma in a plasma processing apparatus of a high-frequency discharge method and arranged in a processing container, characterized in that: A plurality of protrusions are discretely formed on the main surface facing the plasma. 39. An electrode plate manufacturing method, which is an electrode plate manufacturing method for manufacturing the electrode plate described in claim 38, characterized in that it comprises: a step of covering the main surface of the electrode main body with a mask having openings corresponding to the protrusions, forming the protrusion in the opening by sputtering conductive metal or semiconductor onto the main surface of the electrode main body from the mask, and A step of removing the mask from the main surface of the electrode body. 40. An electrode plate provided in a processing container for generating plasma in a high-frequency discharge plasma processing apparatus, characterized in that: A plurality of recesses are discretely formed on the main surface facing the plasma. 41. A method of manufacturing an electrode plate for manufacturing the electrode plate of claim 40, comprising: a step of covering the main surface of the electrode substrate with a mask having openings corresponding to the recesses, spraying solid particles or liquid from the upper surface of the mask to the main surface of the electrode substrate, physically removing the electrode substrate portion in the opening of the electrode substrate to form the recess, and A step of removing the mask from the main surface of the electrode substrate. 42. The electrode plate manufacturing method according to claim 39 or 41, characterized in that: The method further includes a step of sputtering a dielectric on the main surface of the electrode substrate from which the mask has been removed to form a first dielectric film. 43. The electrode plate manufacturing method according to claim 42, characterized in that: In addition, after the first dielectric film is formed to a thickness covering the entire main surface of the electrode substrate, an electrode material is thermally sprayed on the first dielectric film to form an electrode for an electrostatic chuck. membrane process, and Then, a step of sputtering a dielectric on the electrode film to form a second dielectric film. 44. An electrode plate provided in a processing container for generating plasma in a plasma processing apparatus of a high-frequency discharge method, characterized in that: A dielectric body is provided on the main surface facing the plasma, and the thickness of the dielectric body on the center side of the first electrode is greater than the thickness of the dielectric body on the electrode edge side.

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