Plasma processing apparatus

Abstract

Provided is a plasma processing device using microwaves, which can suppress reflected waves and radiate circularly polarized waves having a high axial ratio, and which can selectively change the radiation mode of the polarized waves. The microwave device is provided with: 2n solid-state element microwave sources (2); 2n coaxial waveguide converters (3) which are respectively connected to the solid-state element microwave sources and which convert microwave power from a TEM mode to a TE10 mode; and a polarized wave combining antenna which is provided with 2n cut-off waveguides (4) connected to the circular waveguide (5) every 180 DEG / n on the same plane perpendicular to the axial direction of the circular waveguide (5), the 2n cut-off waveguides are connected to the 2n coaxial waveguide converters in a one-to-one relationship, and in the cut-off waveguides, the microwave power of the TE10 mode is blocked, and an evanescent field is excited to the circular waveguide.

Description

Technical Field

[0001] The present invention relates to an ECR (Electron Cyclotron Resonance) plasma processing device using microwaves. Background Art

[0002] In recent years, the integration of semiconductor devices has increased, requiring micro-machining, that is, improving processing accuracy, and the uniformity of etching rate or the uniformity of CD value (Critical Dimension) in the processing size of the wafer surface has become strict. In addition, the etched material has also changed from a single-layer film to a multi-layer film, and multi-stage step etching that changes the etching conditions is often used in the processing of each multi-layer film. In this case, since the main factors that affect the uniformity of etching are different for each step, it is difficult to obtain the uniformity and axial symmetry of the etching rate at the time when the etching of each multi-layer film is completed.

[0003] One of the miniaturization etching technologies in the semiconductor field is dry etching technology, among which dry etching processing using plasma is particularly often used. Plasma uses collisions with electrons and molecules or atoms of the processing gas to excite the molecules or atoms of the processing gas to generate ions and free radicals. The plasma processing device realizes anisotropic etching through ions and isotropic etching through free radicals. As a plasma source, there is electron cyclotron resonance ECR (ECR: Electron Cyclotron Resonance). Since ECR can generate high-density plasma, it is used in improving the withstand voltage of DRAM of semiconductor devices and making high-capacitance capacitors.

[0004] exist Figure 8 The structure of the existing ECR etching device is shown. The 2.45 GHz microwave emitted from the magnetron 72 is set to the TE10 mode in the order of the isolator 73, the rectangular waveguide 74 and the three-stub tuner 75 for propagation, and its propagation posture (or mode) is converted into the TE11 mode through the circular rectangular waveguide converter 76. The circular rectangular waveguide converter 76 has a diameter of φ90 mm so that the 2.45 GHz microwave can pass through the basic TE11 mode propagation posture. In order to form the radiation of microwaves with axisymmetry, a quartz dielectric 1 / 4 wavelength plate 8 is used to form a circularly polarized wave, so that the microwaves in the TE11 mode propagation posture are rotated in time, thereby the electric field distribution of the microwaves becomes axisymmetric and radiated to the chamber 6. In order to make the microwaves propagate into the circular waveguide 5 as circularly polarized waves, the aforementioned 1 / 4 wavelength plate 8 is inserted into the circular waveguide 5 at an angle of 45 degrees relative to the polarization plane of the linearly polarized wave of the TE11 mode.

[0005] The circularly polarized waves of microwaves incident into the chamber 6 are introduced into the processing chamber 1 through the quartz window 13 and the shower plate 14 located at the upper part of the processing chamber 1 covered by the upper electromagnetic coil 9, the middle electromagnetic coil 10, and the lower electromagnetic coil 11. The electron cyclotron motion is caused by the electric field caused by the microwaves and the magnetic field formed in the perpendicular direction. When the frequency of the microwaves is 2.45 GHz, the direction of travel of the electrons based on the Lorentz force perpendicular to the magnetic field is bent, so the electrons gradually perform a circular motion. The magnetic flux density B at this time is calculated by the formula: fc=eB / 2πme (e is the electron charge 1.6×10 -19 C, me is the mass of electron 9.1×10 -31 When Kg, fc is 2.45 GHz) is set to 875 G, electron cyclotron resonance is caused, and the probability of collision between electrons and gas molecules in the processing chamber 1 is increased, so high-density plasma can be generated even under low pressure.

[0006] The pressure in the processing chamber 1 is reduced to about 1 Pa by the vacuum pump 17 during the etching process. In this pressure range, 10 11 cm -3 In addition, since the plasma formation and the energy of the individual ions can be controlled by the RF power supply 16 applied to the substrate stage 15, precise shape control can be performed. Furthermore, in order to improve the in-plane uniformity of the substrate w to be processed, a 1 / 4 wavelength plate 8 is used to inject circularly polarized waves into the processing chamber 1.

[0007] The axial ratio of the circularly polarized wave based on the 1 / 4 wavelength plate 8 in the prior art does not take into account the reflection from the processing chamber 1. Therefore, if the plasma density in the processing chamber 1 becomes a fixed value, a reflected wave will be generated from the processing chamber 1. Since the reflected wave forms a standing wave with the incident wave, the rotation of the TE11 mode electric field in the circular waveguide 5 is hindered, and the axial ratio of the circularly polarized wave that is expected to be input into the processing chamber 1 will be reduced. In addition, the axial ratio is defined as the circularity of the circularly polarized wave, and 1 is the highest circularity.

[0008] In order to perform uniform plasma processing on the substrate w to be processed, the distribution of plasma characteristics such as plasma density and temperature near the substrate w to be processed is of course important. From the perspective of making the plasma processing uniform, a technology for optimizing the plasma distribution is important.

[0009] Plasma processing devices that generate plasma using microwave power have the characteristics of being able to generate high-density plasma even at low pressure, and being able to easily control the distribution of plasma by adjusting the static magnetic field distribution together with the static magnetic field, and are widely used in the manufacture of semiconductor processing devices, etc. In response to the aforementioned trend of increasing the diameter of substrates, the control of plasma distribution is also important in microwave plasma processing devices. However, the wavelength of microwaves is as short as a few centimeters to more than ten centimeters, and the electric field distribution of microwaves on semiconductor substrates of the same size as the wavelength is easily changed. In order to obtain uniform plasma processing over a wide range, it is a problem to optimize the distribution of microwaves.

[0010] As a conventional technology for using circularly polarized microwaves in a plasma source for generating plasma using microwaves, there are, for example, the following prior art documents.

[0011] Prior Art Literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Publication No. 2010-192750

[0014] Patent Document 2: Japanese Patent Application Publication No. 2003-188152

[0015] Patent Document 3: Japanese Patent Application Publication No. 2006-339547

[0016] Non-patent literature

[0017] Non-patent document 1: Michael A. Lieberman et al., “Principles of Plasma Discharges and Materials Processing” John Wiley & Sons, Inc. (2005) Summary of the invention

[0018] Problems to be solved by the invention

[0019] The etching of semiconductor device structure patterns, especially the shape accuracy and etching rate uniformity of gate processing that dominates the operating characteristics of semiconductor devices, are becoming more and more stringent every year. In order to solve the above problems, many ECR plasma distribution control technologies used in dry etching have been proposed.

[0020] As a prior art, in Patent Document 1, for a single-mode microwave such as TE10 from a rectangular waveguide connected to a magnetron, a wavelength plate of 1 / 4λg (λg shown here is the wavelength of the electromagnetic wave in a φ90mm circular waveguide at 2.45GHz) is inserted into a circular waveguide connected to the aforementioned rectangular waveguide, a rotating electric field of the TE11 mode is formed in the circular waveguide, and the processing chamber of the plasma processing device is radiated, thereby achieving high etching rate uniformity. However, the angle between the phase plate of Patent Document 1 and the main polarization plane is 45° clockwise, and only right-handed electromagnetic waves can be radiated in the etching process (hereinafter, right-handed electromagnetic waves are referred to as R waves, and left-handed electromagnetic waves are referred to as L waves).

[0021] As shown in non-patent document 1, the electromagnetic wave energy of the R wave continuously accelerates the electrons entangled in the magnetic field lines by the Lorentz force in an environment with a magnetic field B, and the energy of the microwave is easily absorbed by the electrons, and the electron temperature Te becomes larger. As a result, as a result of the electron shielding effect on the fine pattern such as FinFET in the semiconductor device structure, the ion trajectory incident on the wall surface of the fin of the dense and sparse parts of the device pattern on the substrate is bent due to the negative electric field of the electron shielding effect, and notches of varying degrees are formed at the root of the fin of the FinFET.

[0022] In Patent Document 2, in order to make the circular waveguide radiate the rotating TE11 mode electromagnetic wave, a cross slit is used at the connection portion between the rectangular waveguide and the circular waveguide. However, Patent Document 2 is similar to Patent Document 1. Since only either the R wave or the L wave can be radiated in the plasma treatment process, in order to design the size and angle of the cross slit corresponding to the determined process conditions, the impedance change in the treatment chamber cannot be followed, and the axial ratio of the radiated circularly polarized wave is sometimes reduced. In addition, when the R wave is selected, as the microwave power input increases, the electron temperature Te becomes too large, and when the L wave is selected, there is a problem of difficulty in plasma ignition.

[0023] In Patent Document 3, two rectangular waveguides are connected in an L shape, and a reflection suppression section connected to a circular waveguide is provided at the right angle of the L shape. By connecting different magnetrons to the incident ends of the two rectangular waveguides, a circularly polarized wave is synthesized in a synthesis chamber connected to the right angle of the L shape. In Patent Document 3, although there is no description of radiating an L wave in the reactor of a plasma processing device, it is considered that an R wave or an L wave can be provided by adjusting the output phase of the two magnetrons. However, since the two rectangular waveguides in the L shape propagate single-mode TE10 microwaves, they can also propagate reflected waves caused by the plasma load in the processing chamber of the plasma processing device. In order to maintain the axial ratio of the circularly polarized wave, a tuner with three short stubs needs to be prepared in the rectangular waveguide section. Moreover, since the TE10 mode propagates, the reflected wave from the reactor also propagates in the rectangular waveguide. The axial ratio of the circularly polarized wave radiated into the reactor changes according to the process conditions of the plasma processing device.

[0024] Means for solving problems

[0025] A plasma processing apparatus according to an embodiment of the present invention comprises: a processing chamber for performing plasma processing; a circular waveguide connected to a cavity of the processing chamber and capable of transmitting TE11 mode microwave power; 2n solid-state element microwave sources, wherein n is a natural number greater than or equal to 2; a phase controller for controlling the phases of microwave power respectively outputted by the solid-state element microwave sources; 2n coaxial waveguide converters respectively connected to the solid-state element microwave sources and converting microwave power from TEM mode to TE10 mode; and a polarization wave synthesis antenna having 2n cutoff waveguides connected to the circular waveguide on the same plane perpendicular to the axial direction of the circular waveguide, the angle between the axial directions of adjacent cutoff waveguides being set to 180° / n, the 2n cutoff waveguides being connected to the 2n coaxial waveguide converters in a one-to-one relationship, the TE10 mode microwave power being blocked in the cutoff waveguide, and an evanescent field being excited to the circular waveguide.

[0026] Effects of the Invention

[0027] According to the present invention, a plasma processing device using microwaves can be provided, which can suppress reflected waves and radiate circularly polarized waves with a high axial ratio, and can selectively change the radiation mode of polarized waves. Other issues and new features will be clarified based on the description of this specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a structural diagram of an ECR plasma processing device.

[0029] Figure 2 It is a horizontal cross-sectional view of the polarization wave combining antenna of Example 1.

[0030] Figure 3A This diagram illustrates the principle of R-wave coupling based on phase control of a solid-state microwave source.

[0031] Figure 3B This diagram illustrates the principle of R-wave coupling based on phase control of a solid-state microwave source.

[0032] Figure 3C This diagram illustrates the principle of R-wave coupling based on phase control of a solid-state microwave source.

[0033] Figure 4 It is a diagram of the electromagnetic field simulation results of the electric field intensity distribution in a circular waveguide based on the combination of the output phases of the solid-state microwave source.

[0034] Figure 5 It is a horizontal cross-sectional view of the polarization wave combining antenna of Example 2.

[0035] Figure 6 It is an example of the combination of polarized waves radiated within an arbitrary fixed time.

[0036] Figure 7 These are simulation results on the change in axial ratio in a circular waveguide caused by the difference in reflection coefficient of the processing device.

[0037] Figure 8 This is a structural diagram of a conventional ECR plasma processing device. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present invention will be described using the drawings.

[0039] [Example 1]

[0040] use Figure 1 to Figure 4 The structure of Example 1 is described below. Figure 1 The overall structure of the ECR plasma processing device of Example 1 is shown. Figure 8 The common structures are marked with the same figure numbers, and repeated descriptions are omitted. The processing chamber 1 becomes a high vacuum container that is depressurized to about 0.1 to 1 Pa by a vacuum pump 17. In the present embodiment, a phase controller 7 is provided, which can control the output phases of multiple solid-state element microwave sources 2 and the on / off operation of power. Multiple solid-state element microwave sources 2 are respectively connected to coaxial waveguide converters 3, and the coaxial waveguide converters 3 are respectively connected to cutoff waveguides 4, and the microwave power from the solid-state element microwave source 2 is introduced from the coaxial waveguide converter 3 into the cutoff waveguide 4.

[0041] In order to radiate microwaves to the chamber 6, a circular waveguide tube 5 with a diameter of 90 mm that can propagate microwaves in the TE11 mode of 2.45 GHz is connected to a plurality of cutoff waveguide tubes 4. Since the output frequency of the solid-state element microwave source 2 becomes 2.45 GHz, in order to block microwaves in the TE10 mode, the width of the cutoff waveguide tube 4 is set to 60 mm, and the length of the circular waveguide tube 5 to the outermost periphery r=45 mm is set to 42.5 mm. The number of connections of the cutoff waveguide tubes 4 is set to 2n (where n is a natural number greater than 2). A polarized wave synthesis antenna is formed at the connection portion between the circular waveguide tube 5 and the plurality of cutoff waveguide tubes 4. Although the cutoff waveguide tube 4 is assumed to be a rectangular waveguide tube, it can also be a circular waveguide tube.

[0042] exist Figure 2 A horizontal cross-sectional view showing the polarized wave combining antenna of Example 1 (equivalent to Figure 1 AA section shown). Figure 2 The cutoff waveguide tubes 4 of the polarized wave synthesis antenna shown are n=2, i.e., 4 in structure, and they are connected at azimuth angles of 0°, 90°, 180°, and 270° on the same plane perpendicular to the axial direction of the circular waveguide tube 5. According to the azimuth angle, the cutoff waveguide tube 4 at an azimuth angle of 0° is denoted as 4#1, the cutoff waveguide tube 4 at an azimuth angle of 90° is denoted as 4#2, the cutoff waveguide tube 4 at an azimuth angle of 180° is denoted as 4#3, and the cutoff waveguide tube 4 at an azimuth angle of 270° is denoted as 4#4. In addition, the parts connecting the four cutoff waveguide tubes 4#1, 4#2, 4#3, and 4#4 and the coaxial waveguide converter 3 are respectively designated as port 1, port 2, port 3, and port 4. In addition, in the case of n≧3, the cutoff waveguide tubes are also connected on the same plane perpendicular to the axial direction of the circular waveguide tube 5 so that the angle between the axial directions of the adjacent cutoff waveguide tubes becomes 180° / n.

[0043] Figure 1 The coaxial waveguide converter 3 and the solid-state microwave source 2 shown are provided with four corresponding to the four cutoff waveguides 4. The output phases of the four solid-state microwave sources 2 are, for example, Figure 3AAs shown, it is controlled to 0π, 1 / 2π, π, 3 / 2π, and introduced into the coaxial waveguide converter 3 to be converted from TEM mode to TE10 mode. Since the microwave of TE10 mode is in the form of electromagnetic wave, it does not propagate in the cutoff waveguide 4, but excites the evanescent field toward the circular waveguide 5 within a certain distance of the cutoff waveguide 4 through its microwave power. The excited evanescent field forms an electric field at the connection part of the cutoff waveguide 4 and the circular waveguide 5 of the polarization wave synthesis antenna, and re-radiates the electromagnetic wave to the circular waveguide 5. At this time, the radiated electromagnetic wave becomes the TE11 mode propagating in the circular waveguide 5. Since the electromagnetic wave of TE11 mode from the circular waveguide 5 is 2.45 GHz, which is the same frequency as the electric field forming the evanescent field, the electromagnetic wave of TE11 mode propagating in the circular waveguide 5 is also 2.45 GHz.

[0044] As described above, as a result, microwaves of TE11 mode are radiated from the circular waveguide 5 of the polarized wave combining antenna to the chamber 6, but electromagnetic wave propagation from the microwave power source (wave source) is not directly utilized. The microwave power source (solid-state element microwave source 2) of this embodiment is used only to excite the evanescent field at the connection portion between the cutoff waveguide 4 and the circular waveguide 5.

[0045] exist Figure 3A to Figure 3C A diagram illustrating the R-wave coupling principle of the phase-controlled solid-state microwave source according to the present invention is shown. Figure 3A This is an example of controlling four solid-state microwave sources 2 by phase controller 7, and setting the phases of four cutoff waveguides 4#1, 4#2, 4#3, and 4#4 to 0°, 90°, 180°, and 270°, respectively. Figure 3B As shown in FIG. 1 , at time O1, the electric field in the -Ex direction is coupled according to the output phase of port 1 and port 3. Figure 3C As shown, at time O2, the electric field in the +Ey direction is coupled by the output phases of port 2 and port 4. By controlling the phase difference between time O1 and time O2 to 1 / 2π, circularly polarized waves are radiated into the circular waveguide 5. Figure 3A The 1-cycle timing diagram of FIG. 1 is an example of synthesizing the circularly polarized wave of the R wave by controlling the phase of the output power from the solid-state element microwave source 2 .

[0046] In addition, if Figure 3A The timing diagram is reversed, that is, if the power supply phases to the cutoff waveguides 4#1, 4#2, 4#3, and 4#4 are set to 270°, 180°, 90°, and 0°, respectively, a circularly polarized wave of L wave is formed in the circular waveguide 5. Figure 3AIn the example, ports 1 and 3, and ports 2 and 4 respectively excite the evanescent field at the same timing, but even the phase combination of ports 1 and 4, and ports 2 and 3 can couple the rotating electric field, i.e., the right-handed circularly polarized wave (R wave), to the circular waveguide 5. In this case, and Figure 3A Compared with the phase combination of port 1 and port 3, and port 2 and port 4 shown, the radiation power is reduced to 1 / 2.

[0047] exist Figure 4 The electromagnetic field simulation results of the electric field intensity distribution in the circular waveguide based on the combination of the solid-state component microwave source output phase are shown. Figure 4 As shown, by controlling the microwave radiation phase of the solid-state element microwave source 2 in the cutoff waveguide 4 connected to the circular waveguide 5 at 4 azimuth angles, circularly polarized waves of R waves and L waves, and elliptically polarized waves of -45°, 45°, 90°, and 0° in the +Ey direction (the clockwise direction of +Ey is set as positive, and the counterclockwise direction is set as negative) can be radiated into the circular waveguide 5 and radiated to the processing chamber 1 through the chamber 6. In this way, if using Figure 2 By controlling the output phase of the solid-state microwave source 2 through the phase controller 7, the electromagnetic wave radiated to the processing chamber 1 can be adjusted. Figure 4 Such circularly polarized waves, elliptically polarized waves, and electricity.

[0048] The electromagnetic wave radiated from the circular waveguide 5 resonates in the chamber 6 of the plasma processing device of this embodiment, and transmits through the quartz window 13 and the shower plate 14 to supply electromagnetic wave power to the processing chamber 1. At this time, a static magnetic field B (not shown) is formed in the processing chamber 1 by the upper electromagnetic coil 9, the middle electromagnetic coil 10, and the lower electromagnetic coil 11, and the process gas G is supplied from the gas hole of the shower plate 14. The electrons entangled in the magnetic field lines of the static magnetic field B are accelerated by the supplied electromagnetic wave, causing electron cyclotron resonance, and as a result, the electromagnetic wave power is absorbed, and the ECR surface (resonance point) of the plasma is formed at a position with a magnetic flux density of 875G in the vacuum container of the processing chamber 1 under reduced pressure, and the plasma is expanded and generated with time.

[0049] [Example 2]

[0050] use Figure 1 , Figure 2 , Figure 5The structure of Example 2 is described below. In Example 1, since the cutoff waveguide tube 4 of the polarized wave synthesis antenna is directly connected to the circular waveguide tube 5, if the formation mechanism of the R wave is explained, the evanescent field excited from the port 1 and the port 3 forms an electric field in the ±Ex direction at the connection portion with the circular waveguide tube 5. On the other hand, an electric field in the ±Ey direction is formed at the port 2 and the port 4. Therefore, the TE11 mode of electric field rotation can be radiated from the circular waveguide tube 5. As shown in Figure 3B , Figure 3C As is known, since the evanescent field excited in the cutoff waveguide 4 forms a linearly polarized wave in the circular waveguide 5 , the connection portion between the cutoff waveguide 4 and the circular waveguide 5 does not necessarily need to be limited to a circle.

[0051] Therefore, in Example 2, Figure 5 In this way, the connection parts with the cutoff waveguide 4 in four directions are made into rectangular shapes that are easy to manufacture, and connected to the circular waveguide 5. Figure 5 The microwave propagating in the rectangular coupling part 501 is TE10 mode, but since the posture is similar to the TE11 mode propagating in the circular waveguide 5 connected to the lower part of the rectangular coupling part 501, there is no extra reflection. Figure 5 The rectangular coupling portion 501 is also as in Example 1, by controlling the phase of the solid-state element microwave source 2, Figure 4 In this way, circularly polarized waves, elliptically polarized waves, and microwaves with adjustable power are radiated to the processing chamber 1 .

[0052] In view of the above situation, the coupled electric field caused by the evanescent field forms linear polarized waves in the ±Ex direction and ±Ey direction respectively. Therefore, as long as the aforementioned linear polarized waves can be propagated, Figure 5 The rectangular coupling portion 501 can be any shape.

[0053] [Example 3]

[0054] use Figure 1 and Figure 6 The structure of Example 3 is described below. In the existing method of radiating circularly polarized waves for plasma processing devices, since the incident wave and the reflected wave become in the form of electromagnetic waves, it is possible to make a structure with the highest axial ratio of circularly polarized waves in the plasma processing conditions, or to design a circular polarizer for each target process. Therefore, rather than for the selectivity of the circularly polarized waves that can be radiated, the device is generally designed to produce R-wave circularly polarized waves from the perspective of ignition properties and plasma density. In contrast, the axial ratio of circularly polarized waves that can be provided by the plasma processing device of the present embodiment is almost independent of the process conditions, and as long as the output phase of the solid-state element microwave source 2 is controlled, R-waves, L-waves, and elliptically circularly polarized waves can be selectively formed in the circular waveguide 5. Utilizing the aforementioned characteristics, in the present Example 3, for example, Figure 6During a certain time t0, the output phase and on / off combination of the four solid-state element microwave sources 2 are controlled by the phase controller 7, and a variety of microwave radiation modes such as R-wave radiation, L-wave radiation, and elliptically circularly polarized waves can be radiated at the desired timing.

[0055] exist Figure 7 A circularly polarized wave generating device based on a 1 / 4 phase plate of a comparative example (reference Figure 8 ) and the circularly polarized wave generating device of this embodiment (reference Figure 1 ) simulation (HFSS (High Frequency Simulation Software)) processing device caused by the difference in reflection coefficient simulation results in the circular waveguide. In this embodiment, the electromagnetic wave of the solid-state element microwave source 2 is not directly radiated from the circular waveguide 5 of the polarization wave synthesis antenna, but the circular polarization wave is indirectly introduced into the circular waveguide 5 through the evanescent field of the cutoff waveguide 4. Therefore, as Figure 7 As shown in FIG. 1 , since the reflected wave from the processing chamber 1 is not easily affected by the plasma etching process or the processing conditions of the film formation, such as the fluctuation of the plasma load caused by the material gas G, the pressure, etc., even if there is a fluctuation of the plasma load, the circularly polarized wave with a high axial ratio can be radiated to the processing chamber 1. Figure 7 As shown, in the structure of this embodiment, unlike the existing 1 / 4 phase plate microwave plasma processing device, even if there is no three-stub tuner as a reflected wave control device in the waveguide path, the reflected wave can be suppressed (because the reflected wave is in the form of an electromagnetic wave, it cannot pass through the cutoff waveguide tube 4), and a circularly polarized wave with a high axial ratio can be radiated.

[0056] In addition, by virtue of Figure 4 Such a phase combination can radiate not only circularly polarized waves but also elliptically polarized waves with different azimuth angles by controlling the output phase of the solid-state element microwave source 2, and can selectively change the radiation mode of polarized waves by the film distribution and etching rate on the processed substrate w. As mentioned above, since the R wave can continuously accelerate the electrons in the direction of the magnetic field formed in the processing chamber 1, a high plasma density can be obtained. On the other hand, as the microwave supply power increases, the electron temperature Te increases, so negative charges are accumulated at the upper end of the fin of the FinFET, and it is difficult to precisely control the gate shape through the electron shielding effect.

[0057] In contrast, according to the plasma processing apparatus of this embodiment, the electron temperature Te can be controlled by selectively switching the R wave and the L wave by the phase controller 7, and the gate shape of the semiconductor device can be precisely processed. In addition, by selectively switching the R wave and the L wave, the absorbed power of the plasma can be adjusted for the entire or regional plasma region formed in the processing chamber 1, so that it is not only necessary to uniformly etch the substrate w to be processed, but also to control the desired etching rate distribution according to the temperature distribution of the substrate stage to be processed. The example of etching is described here, but the same is true in the case of film formation.

[0058] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modified examples. For example, the above-mentioned embodiments are described in detail in order to explain the present invention in an easy-to-understand manner, but are not necessarily limited to all structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a certain embodiment. In addition, with respect to a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0059] Description of Reference Numerals

[0060] 1…Processing room

[0061] 2… Solid-state microwave source

[0062] 3…Coaxial waveguide converter

[0063] 4…Cut-off waveguide

[0064] 5…Circular waveguide

[0065] 6…Chamber

[0066] 7…Phase controller

[0067] 9… Upper solenoid coil

[0068] 10…Medium electromagnetic coil

[0069] 11…Lower solenoid coil

[0070] 12…Yoke

[0071] 13…Quartz window

[0072] 14…Shower Panel

[0073] 15…Substrate carrier to be processed

[0074] 16…RF power supply

[0075] 17…Vacuum pump

[0076] w…Substrate to be processed

[0077] G…Material gas

[0078] 501 ... rectangular coupling portion.

Claims

1. A plasma processing device, characterized in that: have: a processing chamber that performs plasma processing; A circular waveguide tube connected to the chamber of the processing chamber and capable of transmitting TE11 mode microwave power; 2n solid-state microwave sources, where n is a natural number greater than 2; A phase controller for controlling the phase of the microwave power respectively output by the solid-state element microwave sources; 2n coaxial waveguide converters, which are respectively connected to the solid-state element microwave source and convert the microwave power from TEM mode to TE10 mode; and A polarized wave synthesis antenna, comprising 2n cutoff waveguides connected to the circular waveguide on the same plane perpendicular to the axial direction of the circular waveguide, wherein the angle between the axial directions of adjacent cutoff waveguides is set to 180° / n. The 2n cutoff waveguides are connected to the 2n coaxial waveguide converters in a one-to-one relationship, In the cutoff waveguide, the microwave power of the TE10 mode is blocked, and an evanescent field is excited toward the circular waveguide.

2. The plasma processing device according to claim 1, wherein: The evanescent field forms an electric field at a connection portion between the cutoff waveguide and the circular waveguide, and radiates TE11 mode microwave power to the circular waveguide.

3. The plasma processing device according to claim 1, wherein: The 2n cutoff waveguides include a first cutoff waveguide and a second cutoff waveguide which are connected to the circular waveguide in a mutually opposed manner. The 2n solid-state element microwave sources include a first solid-state element microwave source and a second solid-state element microwave source. The phase controller causes the microwaves generated by the first solid-state device microwave source connected to the first cutoff waveguide to have microwaves with opposite phases to the microwaves generated by the second solid-state device microwave source connected to the second cutoff waveguide.

4. The plasma processing device according to claim 3, wherein: Assuming that n=2, the 2n cutoff waveguides include a third cutoff waveguide and a fourth cutoff waveguide connected to the circular waveguide in an opposite manner to each other, and the 2n solid-state element microwave sources include a third solid-state element microwave source and a fourth solid-state element microwave source, The phase controller causes the third solid-state element microwave source connected to the third cutoff waveguide to generate microwaves whose phases are shifted by 1 / 2π from the microwaves generated by the first solid-state element microwave source, and causes the fourth solid-state element microwave source connected to the fourth cutoff waveguide to generate microwaves whose phases are shifted by 4 / 2π from the microwaves generated by the first solid-state element microwave source.

5. The plasma processing apparatus according to claim 1, wherein: Assuming that n=2, the connection portion between the 2n cutoff waveguides and the circular waveguide in the polarization beam combining antenna is formed into a rectangular shape.

6. The plasma processing apparatus according to claim 1, wherein: The phase controller can switch the microwave radiation mode of the microwaves propagating in the circular waveguide and radiating to the processing chamber by switching the phases of the microwaves generated by the 2n solid-state element microwave sources and / or turning on / off the outputs of the 2n solid-state element microwave sources.

7. The plasma processing apparatus according to claim 6, wherein: The phase controller couples any one of right-handed circularly polarized microwaves, left-handed circularly polarized microwaves, and elliptically polarized microwaves with a given azimuth angle in the same plane perpendicular to the axial direction of the circular waveguide into the circular waveguide by switching the phases of the microwaves generated by the 2n solid-state element microwave sources and / or turning on / off the outputs of the 2n solid-state element microwave sources.

8. The plasma processing apparatus according to claim 7, wherein: During the plasma processing in the processing chamber, a microwave irradiation mode of the microwaves irradiated to the processing chamber is switched.

9. The plasma processing apparatus according to claim 8, wherein: The plasma processing in the processing chamber is a plasma etching processing or a film forming processing.

Images