Plasma processing equipment

Abstract

Provided is a plasma processing device using microwaves, capable of suppressing a reflected wave and emitting a circularly polarized wave having a high axial ratio, and also capable of selectively changing the mode of emission of the polarized wave. This plasma processing device comprises: 2n solid-state element microwave sources 2; 2n coaxial waveguide converters 3 that are respectively connected to the solid-state element microwave sources and that convert microwave power from a TEM mode to a TE10 mode; and a polarization synthesis antenna provided with 2n cut-off waveguides 4 that are connected to a circular waveguide at every 180° / n on the same plane perpendicular to the axial direction of the circular waveguide 5. The 2n cut-off waveguides are connected with the 2n coaxial waveguide converters in a one-to-one relationship, TE10-mode microwave power is cut off in the cut-off waveguides, and an evanescent field is excited toward the circular waveguide.

Description

[Technical Field]

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

[0002] In recent years, the integration density of semiconductor devices has increased, requiring finer processing, i.e., improved processing accuracy. At the same time, it has become more stringent to improve the uniformity of the etching rate and the CD (Critical Dimension) value within the wafer surface in processing dimensions. Furthermore, the materials to be etched have changed from single-layer films to multilayer films, and multi-step etching, in which the etching conditions are changed during the processing of each multilayer film, has become common. In this case, factors that affect the etching uniformity, etc., differ for each step, making it difficult to achieve uniformity of the etching rate and axial symmetry at the completion of etching of each multilayer film.

[0003] Dry etching is one of the micro-etching techniques used in the semiconductor field, and among these, dry etching using plasma is particularly commonly used. Plasma uses collisions between electrons and the molecules or atoms of the process gas to excite the molecules or atoms of the process gas, generating ions and radicals. Plasma processing equipment achieves anisotropic etching using ions and isotropic etching using radicals. Electron cyclotron resonance (ECR) is one plasma source. Because ECR can generate high-density plasma, it is used to improve the withstand voltage of DRAM in semiconductor devices and to create high-capacity capacitors.

[0004] Figure 8 shows the configuration of a conventional ECR etching system. A 2.45 GHz microwave emitted from a magnetron 72 propagates through an isolator 73, a rectangular waveguide 74, and a three-stub tuner 75 in the TE10 mode. The propagation mode (or mode) is then converted to the TE11 mode by a circular-to-rectangular waveguide converter 76. The circular-to-rectangular waveguide converter 76 has a diameter of 90 mm so that the 2.45 GHz microwave can pass through in the fundamental TE11 mode propagation mode. To generate axially symmetric microwave radiation, a quartz dielectric quarter-wave plate 8 is used to form a circularly polarized wave. By rotating the microwave in the TE11 mode propagation mode over time, the microwave electric field distribution becomes axially symmetric and is radiated into the cavity 6. In order to propagate the microwave as a circularly polarized wave within the circular waveguide 5, the aforementioned quarter-wave plate 8 is inserted into the circular waveguide 5 at an angle of 45 degrees to the polarization plane of the linearly polarized wave in the TE11 mode.

[0005] The circularly polarized microwaves incident on the cavity 6 are introduced into the processing chamber 1 through the quartz window 13 and shower plate 14 located at the top of the processing chamber 1, which is covered by the upper electromagnetic coil 9, middle electromagnetic coil 10, and lower electromagnetic coil 11. The electric field caused by the microwave and the magnetic field formed perpendicular to it cause electron cyclotron motion. When the microwave frequency is 2.45 GHz, electrons perpendicular to the magnetic field have their direction of travel bent by the Lorentz force, and the electrons gradually begin to move in circular motion. The magnetic flux density B at this time is calculated using the formula: fc = eB / 2πme (e is the electron charge, 1.6 x 10 -19 C, me is the electron mass 9.1 × 10 -31 Kg, fc is 2.45 GHz), electron cyclotron resonance occurs when the frequency is set to 875 G, and the probability of collision between electrons and gas molecules in the processing chamber 1 increases, making it possible to generate high-density plasma even under low pressure.

[0006] The pressure in the processing chamber 1 is reduced to about 1 Pa by the vacuum pump 17 during etching processing, and in this pressure range, 11 cm -3High density plasma as described above can be obtained. Furthermore, precise shape control is possible because the plasma formation and independent ion energy can be controlled by the RF power supply 16 applied to the substrate stage 15. Furthermore, to improve the in-plane uniformity of the substrate w to be processed, a circularly polarized wave is introduced into the processing chamber 1 using a quarter-wave plate 8.

[0007] The axial ratio of the circularly polarized wave generated by the quarter-wave plate 8 of the prior art does not take into account reflection from the processing chamber 1, and therefore, when the plasma density in the processing chamber 1 reaches a certain value, a reflected wave is generated from the processing chamber 1. This reflected wave forms a standing wave with the incident wave, which hinders the rotation of the TE11 mode electric field in the circular waveguide 5 and reduces the axial ratio of the circularly polarized wave that is to be input into the processing chamber 1. The axial ratio is defined as the circularity of the circularly polarized wave, with 1 being the highest circularity ratio.

[0008] In order to perform uniform plasma processing on the substrate w to be processed, it goes without saying that the distribution of plasma characteristics such as plasma density and temperature near the substrate w to be processed is important, and technology to optimize the plasma distribution from the perspective of uniform plasma processing is important.

[0009] Plasma processing equipment that generates plasma using microwave power can generate high-density plasma even under low pressure, and when used in conjunction with a static magnetic field, the plasma distribution can be easily controlled by adjusting the static magnetic field distribution. These features make them widely used in semiconductor processing equipment manufacturing. In response to the trend toward larger substrate diameters, controlling the plasma distribution is also important in microwave plasma processing equipment. However, microwave wavelengths are short, ranging from a few centimeters to several dozen centimeters, and the microwave electric field distribution on semiconductor substrates with dimensions on the same order as the wavelength is prone to change. Therefore, optimizing the microwave distribution to achieve uniform plasma processing over a wide area presents a challenge.

[0010] In a plasma source that generates plasma using microwaves, the following prior art documents, for example, are known as conventional techniques that use circularly polarized microwaves. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-192750 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-188152 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-339547 [Non-patent literature]

[0012] [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 [Problem to be solved by the invention]

[0013] The etching of structural patterns in semiconductor devices, particularly the shape accuracy of gate processing that governs the operating characteristics of semiconductor devices, and the uniformity of the etching rate are becoming increasingly stringent.To solve the above-mentioned issues, many distribution control technologies for ECR plasma used in dry etching have been proposed.

[0014] In the prior art, Patent Document 1 discloses a technique in which a single-mode microwave such as TE10 is transmitted from a rectangular waveguide connected to a magnetron by inserting a 1 / 4λg wave plate (λg shown here is the wavelength of the electromagnetic wave in a φ90 mm circular waveguide at 2.45 GHz) into a circular waveguide connected to the rectangular waveguide, forming a rotating electric field in TE11 mode within the circular waveguide, which is then radiated into the processing chamber of a plasma processing apparatus, thereby achieving a high uniformity in etching rate. However, the phase plate in Patent Document 1 forms an angle of 45° clockwise with the main polarization plane, and can only radiate right-handed electromagnetic waves (hereinafter, right-handed electromagnetic waves will be referred to as R-waves and left-handed electromagnetic waves as L-waves) during the etching process.

[0015] As shown in Non-Patent Document 1, in an environment with a magnetic field B, the electromagnetic energy of R waves is continuously accelerated by the Lorentz force into electrons wrapped around the magnetic field lines, which makes it easier for the microwave energy to be absorbed by the electrons, increasing the electron temperature Te. This causes an electron-shelling effect on the top of fine patterns such as FinFETs in semiconductor device structures, and as a result, the ion trajectories incident on the wall surfaces of the fins in the dense and sparse portions of the device pattern on the substrate are bent by the negative electric field of the electron-shelling effect, resulting in the formation of notches of varying degrees at the base of the fins of the FinFET.

[0016] In Patent Document 2, a cross slot is used at the connection between the rectangular and circular waveguides to radiate rotational TE11 mode electromagnetic waves from the circular waveguide, but like Patent Document 1, Patent Document 2 can only radiate R-waves or L-waves during the plasma processing process, and because the dimensions and angle of the cross slot are designed according to fixed process conditions, it cannot follow changes in impedance within the processing chamber, which can lead to a decrease in the axial ratio of the radiated circularly polarized waves. Furthermore, when R-waves are selected, the electron temperature Te becomes too high as the input microwave power increases, and when L-waves are selected, there is the issue of difficulty in plasma ignition.

[0017] Patent Document 3 connects two rectangular waveguides in an L-shape, with a reflection suppression section at the right angle of the L-shape, connecting them to a circular waveguide. By connecting different magnetrons to the input ends of the two rectangular waveguides, circularly polarized waves are combined in a combining chamber connected to the right angle of the L-shape. Patent Document 3 does not mention radiating L waves into the reactor of a plasma processing device, but it is believed that adjusting the output phase of the two magnetrons can provide R or L waves. However, because the two L-shaped rectangular waveguides can propagate single-mode TE10 microwaves, reflected waves due to the plasma load in the processing chamber of the plasma processing device can also propagate. To maintain the axial ratio of the circularly polarized waves, a three-stub tuner is required for the rectangular waveguide section. Furthermore, because the TE10 mode propagates, reflected waves from the reactor also propagate within the rectangular waveguide. Therefore, the axial ratio of the circularly polarized waves radiated into the reactor changes depending on the process conditions of the plasma processing device. [Means for solving the problem]

[0018] A plasma processing apparatus according to one embodiment of the present invention includes a processing chamber for performing plasma processing, a circular waveguide connected to a cavity of the processing chamber and capable of propagating microwave power in TE11 mode, 2n solid-state microwave sources, where n is a natural number greater than or equal to 2, a phase controller for controlling the phase of the microwave power output by each of the solid-state microwave sources, 2n coaxial-waveguide converters connected to each of the solid-state microwave sources and converting the microwave power from TEM mode to TE10 mode, and a polarization combining antenna having 2n cutoff waveguides connected to the circular waveguides on the same plane perpendicular to the axial direction of the circular waveguides, the angle between the axial directions of adjacent cutoff waveguides being 180° / n, and the 2n cutoff waveguides are connected to the 2n coaxial-waveguide converters in a one-to-one relationship, and the TE10 mode microwave power is blocked in the cutoff waveguides and an evanescent field is excited toward the circular waveguides. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a microwave plasma processing apparatus that can radiate circularly polarized waves with a high axial ratio by suppressing reflected waves, and that can selectively change the radiation form of the polarized waves. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an ECR plasma processing apparatus. [Figure 2] 1 is a horizontal cross-sectional view of a polarization combining antenna according to a first embodiment. [Figure 3A] FIG. 1 is an explanatory diagram of the principle of R-wave coupling by phase control of a solid-state microwave source. [Figure 3B] FIG. 1 is an explanatory diagram of the principle of R-wave coupling by phase control of a solid-state microwave source. [Figure 3C] FIG. 1 is an explanatory diagram of the principle of R-wave coupling by phase control of a solid-state microwave source. [Figure 4] 10A and 10B are diagrams showing the results of an electromagnetic field simulation of the electric field strength distribution in a circular waveguide according to the combination of the output phases of a solid-state microwave source. [Figure 5] FIG. 10 is a horizontal cross-sectional view of the polarization combining antenna of the second embodiment. [Figure 6] This is an example of a combination of polarizations emitted within an arbitrary fixed time period. [Figure 7] 10 shows the results of a simulation of the change in the axial ratio in a circular waveguide due to differences in the reflection coefficient of the processing device. [Figure 8] FIG. 1 is a diagram showing the configuration of a conventional ECR plasma processing apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0022] The configuration of Example 1 will be described using Figures 1 to 4. Figure 1 shows the overall configuration of an ECR plasma processing apparatus of Example 1. Components common to those in Figure 8 are assigned the same reference numerals, and duplicated explanations will be omitted. The processing chamber 1 is a high-vacuum vessel depressurized to approximately 0.1 to 1 Pa by a vacuum pump 17. In this example, a phase controller 7 is provided, which can control the output phase and power ON / OFF operation of multiple solid-state microwave sources 2. Each of the multiple solid-state microwave sources 2 is connected to a coaxial-waveguide converter 3, and each of the coaxial-waveguide converters 3 is connected to a cutoff waveguide 4, and microwave power from the solid-state microwave source 2 is introduced from the coaxial-waveguide converter 3 to the cutoff waveguide 4.

[0023] In order to radiate microwaves into the cavity 6, a circular waveguide 5 with a diameter of 90 mm, which can propagate microwaves in the TE11 mode at 2.45 GHz, is connected to multiple cutoff waveguides 4. Since the output frequency of the solid-state microwave source 2 is 2.45 GHz, the width of the cutoff waveguide 4 is 60 mm, and the length up to the outermost periphery r = 45 mm of the circular waveguide 5 is 42.5 mm, so that microwaves in the TE10 mode can be blocked. The number of connected cutoff waveguides 4 is 2n (where n is a natural number greater than or equal to 2). A polarization combining antenna is formed at the connection points between the circular waveguide 5 and multiple cutoff waveguides 4. Although the cutoff waveguide 4 is assumed to be a rectangular waveguide, it may also be a circular waveguide.

[0024] Figure 2 shows a horizontal cross section of the polarization combining antenna of Example 1 (corresponding to cross section AA shown in Figure 1). The polarization combining antenna shown in Figure 2 has n=2, i.e., four cutoff waveguides 4, which are connected at 0°, 90°, 180°, and 270° angles on the same plane perpendicular to the axial direction of the circular waveguide 5. Depending on the angle, the cutoff waveguide 4 at 0° angle will be referred to as 4#1, the cutoff waveguide 4 at 90° angle as 4#2, the cutoff waveguide 4 at 180° angle as 4#3, and the cutoff waveguide 4 at 270° angle as 4#4. The points where the four cutoff waveguides 4#1, 4#2, 4#3, and 4#4 are connected to the coaxial-waveguide converter 3 will be referred to as port 1, port 2, port 3, and port 4, respectively. Even when n≧3, the cutoff waveguides are connected on the same plane perpendicular to the axial direction of the circular waveguide 5 so that the angle between adjacent cutoff waveguides in the axial direction is 180° / n.

[0025] Four coaxial-waveguide converters 3 and four solid-state microwave sources 2 are provided, one for each of the four cutoff waveguides 4. The output phases of the four solid-state microwave sources 2 are controlled to, for example, 0π, 1 / 2π, π, and 3 / 2π as shown in Figure 3A. The output phases are then introduced into the coaxial-waveguide converter 3, where they are converted from TEM mode to TE10 mode. Because TE10 mode microwaves are in the form of electromagnetic waves, they do not propagate within the cutoff waveguide 4. Instead, their microwave power excites an evanescent field toward the circular waveguide 5 within a certain distance of the cutoff waveguide 4. The excited evanescent field forms an electric field at the junction of the cutoff waveguide 4 and the circular waveguide 5 of the polarization combining antenna, thereby radiating an electromagnetic wave back into the circular waveguide 5. The radiated electromagnetic wave propagates in the TE11 mode within the circular waveguide 5. The TE11 mode electromagnetic wave from the circular waveguide 5 has the same frequency of 2.45 GHz as the frequency at which the electric field of the evanescent field is formed, so the TE11 mode electromagnetic wave propagating through the circular waveguide 5 also has a frequency of 2.45 GHz.

[0026] As explained above, microwaves in TE11 mode are ultimately radiated from the circular waveguide 5 of the polarization combining antenna toward the cavity 6, but electromagnetic wave propagation from the microwave power supply (wave source) is not directly utilized. The microwave power supply (solid-state microwave source 2) of this embodiment is used solely to excite an evanescent field at the junction between the cutoff waveguide 4 and the circular waveguide 5.

[0027] Figures 3A-3C illustrate the principle of R-wave coupling by phase control of solid-state microwave sources according to the present invention. Figure 3A shows an example in which four solid-state microwave sources 2 are controlled by a phase controller 7, with the phases of the four cutoff waveguides 4#1, 4#2, 4#3, and 4#4 set to 0°, 90°, 180°, and 270°, respectively. As shown in Figure 3B, at time O1, an electric field in the -Ex direction is coupled by the output phases of ports 1 and 3. Similarly, as shown in Figure 3C, at time O2, an electric field in the +Ey direction is coupled by the output phases of ports 2 and 4. By controlling the phase difference between time O1 and time O2 to 1 / 2π, a circularly polarized wave is radiated into the circular waveguide 5. The timing chart for one period in Figure 3A shows an example in which a circularly polarized R-wave is coupled by phase control of the output power from the solid-state microwave sources 2.

[0028] Note that if the timing chart in Figure 3A is reversed, that is, if the phases of the power supplied to cutoff waveguides 4#1, 4#2, 4#3, and 4#4 are set to 270°, 180°, 90°, and 0°, respectively, circularly polarized L-waves will be formed in circular waveguide 5. Furthermore, in Figure 3A, ports 1 and 3, and ports 2 and 4, respectively, excite evanescent fields at the same timing, but even with the phase combinations of ports 1 and 4 and ports 2 and 3, it is possible to couple a rotating electric field, i.e., right-handed circularly polarized waves (R-waves), into circular waveguide 5. However, in this case, the radiated power will be half that of the phase combinations of ports 1 and 3 and ports 2 and 4 shown in Figure 3A.

[0029] Figure 4 shows the results of an electromagnetic field simulation of the electric field intensity distribution within a circular waveguide depending on the combination of solid-state microwave source output phases. As shown in Figure 4, by controlling the microwave radiation phase of the solid-state microwave source 2 into the cutoff waveguides 4 connected to the four corners of the circular waveguide 5, circularly polarized R-waves and L-waves, as well as elliptically polarized waves at -45°, 45°, 90°, and 0° in the +Ey direction (+Ey clockwise is positive, counterclockwise is negative), are radiated into the circular waveguide 5, which then passes through the cavity 6 and is radiated into the processing chamber 1. In this way, by controlling the spatial arrangement of the four cutoff waveguides 4 of the polarization combining antenna in Figure 2 and the output phase of the solid-state microwave source 2 using the phase controller 7 and the phase control in Figure 3, it is possible to adjust the circular polarization, elliptical polarization, and power of the electromagnetic waves radiated into the processing chamber 1, as shown in Figure 4.

[0030] The electromagnetic waves emitted from the circular waveguide 5 resonate in the cavity 6 of the plasma processing apparatus of this embodiment, passing through the quartz window 13 and shower plate 14, and supplying electromagnetic 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, middle electromagnetic coil 10, and lower electromagnetic coil 11, and a process gas G is supplied through the gas holes in the shower plate 14. Electrons wrapped around the magnetic field lines of the static magnetic field B are accelerated by the supplied electromagnetic waves, causing electron cyclotron resonance, which ultimately absorbs the electromagnetic wave power, forming a plasma ECR surface (resonance point) at a location where the magnetic flux density is 875 G in the reduced-pressure vacuum vessel of the processing chamber 1, and the plasma expands and is generated over time. [Example]

[0031] The configuration of Example 2 will be described using Figures 1, 2, and 5. In Example 1, the cutoff waveguide 4 of the polarization combining antenna is directly connected to the circular waveguide 5. Therefore, in terms of the R-wave formation mechanism, at the connection with the circular waveguide 5, the evanescent fields excited from ports 1 and 3 form an electric field in the ±Ex directions. On the other hand, an electric field in the ±Ey directions is formed at ports 2 and 4. Therefore, the TE11 mode, in which the electric field rotates, can be emitted from the circular waveguide 5. As can be seen in Figures 3B and 3C, the evanescent field excited in the cutoff waveguide 4 forms a linearly polarized wave within the circular waveguide 5, so the connection between the cutoff waveguide 4 and the circular waveguide 5 does not necessarily have to be circular.

[0032] For this reason, in the second embodiment, the connection portion with the four-way cutoff waveguide 4 is formed as a rectangle, which is easy to manufacture, and is connected to the circular waveguide 5, as shown in Fig. 5. The microwaves propagating through the rectangular coupling portion 501 in Fig. 5 are in the TE10 mode, but this is very similar to the behavior of the TE11 mode propagating through the circular waveguide 5 connected to the bottom of the rectangular coupling portion 501, so there is no unnecessary reflection. For this reason, even when the rectangular coupling portion 501 in Fig. 5 is provided, by controlling the phase of the solid-state microwave source 2 as in the first embodiment, it is possible to radiate circularly polarized waves, elliptically polarized waves, and microwaves with adjustable power to the processing chamber 1, as shown in Fig. 4.

[0033] In view of the above, since the coupled electric field due to the evanescent field forms linearly polarized waves in the ±Ex and ±Ey directions, rectangular coupling portion 501 in FIG. 5 may have any shape as long as the linearly polarized waves can be propagated. [Example]

[0034] The configuration of Example 3 will be described using Figures 1 and 6. In conventional methods for radiating circularly polarized waves into a plasma processing apparatus, the incident and reflected waves are in the form of electromagnetic waves. Therefore, circular polarizers have been designed for the configuration with the highest circular polarization axial ratio among the plasma processing conditions, or for each target process. As a result, there is no selectivity for the circular polarization that can be radiated, and the apparatus is generally designed to radiate R-wave circular polarization from the perspective of ignition ability and plasma density. In contrast, the axial ratio of the circular polarization that can be provided by the plasma processing apparatus of this example is almost independent of the process conditions. By controlling the output phase of the solid-state microwave source 2, R-wave, L-wave, and elliptical circular polarization can be selectively generated within the circular waveguide 5. By utilizing the above-described characteristics, Example 3 can radiate a wide variety of microwave radiation forms, such as R-wave radiation, L-wave radiation, and elliptical circular polarization, at the desired timing by controlling the output phase and ON / OFF combination of the four solid-state microwave sources 2 using the phase controller 7 during a certain time period t0, for example, as shown in Figure 6.

[0035] Figure 7 shows the results of a simulation (using HFSS (High Frequency Simulation Software)) of the change in axial ratio within the circular waveguide due to differences in the reflection coefficient of the processing equipment for a comparative circularly polarized wave generator using a quarter-wave plate (see Figure 8) and the circularly polarized wave generator of this embodiment (see Figure 1). In this embodiment, the electromagnetic waves from the solid-state microwave source 2 are not directly emitted from the circular waveguide 5 of the polarization combining antenna, but rather the circularly polarized waves are indirectly introduced into the circular waveguide 5 by the evanescent field of the cutoff waveguide 4. Therefore, as shown in Figure 7, the system is less susceptible to reflected waves from the processing chamber 1 due to fluctuations in the plasma load caused by processing conditions during the plasma etching process or film formation, such as the material gas G and pressure, and therefore can radiate circularly polarized waves with a high axial ratio into the processing chamber 1 even if the plasma load fluctuates. As shown in FIG. 7, in the configuration of this embodiment, unlike conventional quarter-phase plate microwave plasma processing apparatuses, reflected waves can be suppressed without providing a three-stub tuner, which is a reflected wave control device, in the waveguide (the reflected waves are in the form of electromagnetic waves and cannot pass through the cutoff waveguide 4), and circularly polarized waves with a high axial ratio can be emitted.

[0036] Furthermore, by using the phase combinations shown in Figure 4, it is possible to radiate not only circularly polarized waves but also elliptically polarized waves with different directions by controlling the output phase of the solid-state microwave source 2, and the polarization radiation form can be selectively changed depending on the film distribution and etching rate on the substrate to be processed w. As mentioned above, the R-wave can continuously accelerate electrons in the direction of the magnetic field formed in the processing chamber 1, thereby obtaining a high plasma density. However, as the microwave supply power increases, the electron temperature Te increases, causing negative charges to accumulate at the top end of the fin of the FinFET, and the electron shielding effect makes it difficult to precisely control the gate shape.

[0037] In contrast, with the plasma processing apparatus of this embodiment, the electron temperature Te can be controlled by selectively switching between R and L waves using the phase controller 7, making it possible to precisely process the gate shape of a semiconductor device. Furthermore, by selectively switching between R and L waves, the absorbed power of the plasma can be adjusted globally or regionally in the plasma region formed in the processing chamber 1, so that not only can a uniform etching rate of the substrate w to be processed be achieved, but also a desired etching rate distribution can be controlled depending on the application, such as the temperature distribution of the substrate support. While an example of etching has been described here, the same applies to film formation.

[0038] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0039] 1...Processing chamber 2...Solid-state microwave source 3... Coaxial waveguide converter 4...Cutoff waveguide 5...Circular waveguide 6...cavity 7...Phase controller 9...Upper electromagnetic coil 10...Middle electromagnetic coil 11...Lower electromagnetic coil 12…York 13...Quartz window 14...Shower plate 15...Substrate stage for processing 16…RF power supply 17...Vacuum pump w...Substrate to be processed G: Material gas 501...Rectangular joint.

Claims

1. a processing chamber for performing plasma processing; a circular waveguide coupled to the cavity of the processing chamber and capable of propagating microwave power in TE11 mode; 2n solid-state microwave sources, where n is a natural number equal to or greater than 2; a phase controller for controlling the phase of microwave power output by each of the solid-state microwave sources; 2n coaxial-waveguide converters connected to each of the solid-state microwave sources to convert the microwave power from a TEM mode to a TE10 mode; a polarization combining antenna including 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 adjacent cutoff waveguides in the axial direction is 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 in TE10 mode is cut off, and an evanescent field is excited toward the circular waveguide.

2. In claim 1, The evanescent field forms an electric field at a connection portion between the cutoff waveguide and the circular waveguide, and radiates microwave power in TE11 mode to the circular waveguide.

3. In claim 1, the 2n cutoff waveguides include a first cutoff waveguide and a second cutoff waveguide connected to the circular waveguide so as to face each other, the 2n solid state microwave sources include a first solid state microwave source and a second solid state microwave source; The phase controller causes the first solid-state microwave source connected to the first cutoff waveguide to generate microwaves that have an opposite phase to microwaves generated by the second solid-state microwave source connected to the second cutoff waveguide.

4. In claim 3, where n=2, the 2n cutoff waveguides include a third cutoff waveguide and a fourth cutoff waveguide connected to the circular waveguide so as to face each other, and the 2n solid-state microwave sources include a third solid-state microwave source and a fourth solid-state microwave source; the phase controller causes the third solid-state microwave source connected to the third cutoff waveguide to generate microwaves that are 1 / 2π out of phase with respect to the microwaves generated by the first solid-state microwave source, and causes the fourth solid-state microwave source connected to the fourth cutoff waveguide to generate microwaves that are 4 / 2π out of phase with respect to the microwaves generated by the first solid-state microwave source.

5. In claim 1, A plasma processing apparatus in which n=2, and a connection portion between the 2n cutoff waveguides and the circular waveguide in the polarization combining antenna is rectangular.

6. In claim 1, The phase controller switches ON / OFF the phases of the microwaves generated by the 2n solid-state microwave sources and / or the outputs of the 2n solid-state microwave sources, thereby enabling switching of the microwave radiation form of the microwaves propagated through the circular waveguide and radiated into the processing chamber.

7. In claim 6, The phase controller switches ON / OFF the phases of the microwaves generated by the 2n solid-state microwave sources and / or the outputs of the 2n solid-state microwave sources, thereby coupling any one of right-handed circularly polarized microwaves, left-handed circularly polarized microwaves, and elliptically polarized microwaves of a predetermined direction contained in the same plane perpendicular to the axial direction of the circular waveguide into the circular waveguide.

8. In claim 7, A plasma processing apparatus that switches a microwave radiation form of microwaves radiated into the processing chamber during a plasma processing period in the processing chamber.

9. In claim 8, The plasma processing apparatus in the processing chamber is a plasma etching process or a film forming process.

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