Plasma processing apparatus

Abstract

In order to provide a plasma processing device capable of generating an axisymmetric electric field distribution under a wide range of conditions without actively losing microwave energy other than plasma generation, and capable of performing uniform processing, this plasma processing device is provided with: a diaphragm polarizer that is provided with a plurality of electrodes; and a transmission unit that transmits the microwaves transmitted through the circulator to the processing chamber, one port of the circulator being connected to one port of the diaphragm polarizer and the other port of the diaphragm polarizer, and the other port of the circulator being connected to a high-frequency power source. One port of the diaphragm polarizer is a port for converting propagated microwaves into right-handed circularly polarized waves, and the other port of the diaphragm polarizer is a port for converting propagated microwaves into left-handed circularly polarized waves.

Description

Technical Field

[0001] This invention relates to plasma processing apparatus. Background Technology

[0002] In the manufacture of semiconductor devices, plasma processing equipment is frequently used in various processes such as etching, film deposition, and cleaning. Therefore, to obtain the desired processing results, various factors, including pressure and gas type, must be adjusted. From a yield perspective, properly controlling the plasma distribution within the processing chamber is one of the important factors for achieving uniform processing across the entire wafer surface.

[0003] In the past, when microwave-based plasma processing devices were used in plasma generation, for example, if the fundamental mode of a cylindrical waveguide, namely the TE11 mode, was introduced into the processing chamber as a linearly polarized wave, the electric field intensity distribution in space would sometimes become non-axisymmetric, resulting in non-uniform processing. As a countermeasure, Patent Document 1 proposes a method that uses a circularly polarized wave generating unit to rotate the polarization plane, thereby making the electric field distribution within the processing chamber axisymmetric.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: JP 2006-179477

[0007] Non-patent literature

[0008] Non-Patent Literature 1: Takeshi Fukusako, “Fundamentals of Circularly Polarized Wave Antennas”, Corona Corporation, 2018, pp. 110-111 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] In methods using circularly polarized wave generation units, the reflected waves from the processing chamber side, whose characteristics vary depending on process conditions, can cause the circularly polarized waves entering the processing chamber to mix with an inversely rotating component, resulting in axially ellipticized waves. This can potentially worsen the uniformity of the plasma distribution. Therefore, Patent Document 1 further proposes a method to suppress the impact on uniformity by setting up a dummy load that absorbs the reflected waves. However, in the method of setting up a dummy load, since the reflected portion of the energy intended for plasma generation is converted into heat, power loss increases, potentially requiring a larger power supply capacity to compensate for it.

[0011] The purpose of this invention is to provide a plasma processing device that does not cause microwave energy to be actively lost due to plasma generation, generates an axisymmetric electric field distribution under a wide range of conditions, and can perform uniform processing.

[0012] Methods for solving problems

[0013] The structure of the present invention for achieving the above objectives is as follows.

[0014] The plasma processing apparatus includes: a processing chamber for plasma processing of a sample; a high-frequency power supply for supplying high-frequency power to microwaves; a magnetic field forming mechanism for forming a magnetic field in the processing chamber; and a sample stage for holding the sample. The plasma processing apparatus also includes: a diaphragm polarizer for propagating microwaves via a circulator into the processing chamber; one port of the circulator is connected via an impedance matching section to one port of the diaphragm polarizer and the other port of the diaphragm polarizer, respectively; the other port of the circulator is connected via the matching section to the high-frequency power supply; one port of the diaphragm polarizer is a port that converts the propagating microwaves into right-hand circularly polarized waves, and the other port of the diaphragm polarizer is a port that converts the propagating microwaves into left-hand circularly polarized waves; the impedance matching section includes a rectangular waveguide, the width and length of which are specified to achieve impedance matching of the propagating microwaves.

[0015] In addition, the plasma processing apparatus includes: a processing chamber for plasma processing of a sample; a high-frequency power supply for supplying high-frequency power to microwaves via a matching unit; a magnetic field forming mechanism for forming a magnetic field in the processing chamber; and a sample stage for holding the sample. The plasma processing apparatus also includes: a Faraday rotor that, when n is set to an integer, rotates the phase of the polarization plane of a linearly polarized wave propagating through the matching unit by (90×n+45) degrees; and a waveguide-type circularly polarized wave converter that switches between right-hand and left-hand circularly polarized waves output whenever the phase of the polarization plane of the linearly polarized wave rotating through the Faraday rotor changes by 90 degrees. The waveguide-type circularly polarized wave converter is disposed between the Faraday rotor and the processing chamber, and impedance matching exists between the Faraday rotor and the waveguide-type circularly polarized wave converter.

[0016] Invention Effects

[0017] According to the present invention, a plasma processing apparatus is provided that does not cause positive loss of microwave energy other than plasma generation, generates an axisymmetric electric field distribution under a wide range of conditions, and can perform uniform processing. Attached Figure Description

[0018] Figure 1 This is a schematic structural diagram of the plasma processing apparatus involved in the embodiments of the present invention.

[0019] Figure 2 This is a schematic structural diagram of the mode converter and circular polarizer involved in the embodiments of the present invention.

[0020] Figure 3 This is a schematic structural diagram of the mode converter and circular polarizer involved in the embodiments of the present invention.

[0021] Figure 4 This is a diagram showing the polarization wave states in each part of the mode converter involved in the embodiments of the present invention. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described using the accompanying drawings.

[0023]

Example 1

[0024] exist Figure 1 This diagram illustrates a plasma processing apparatus according to an embodiment of the present invention. Microwaves with a frequency of 2.45 GHz, generated by a microwave source 1 such as a magnetron, are transmitted via a square waveguide 2 through an isolator 3 and a matching device 4 to a mode converter 5. The microwaves transmitted to the mode converter 5 are further radiated via a cylindrical waveguide 6 to a cylindrical cavity 7, thereby generating plasma in a processing chamber 9 located below the cylindrical cavity 7 and separated by a microwave inlet window 8. A gas inlet system (not shown) and a vacuum exhaust system are connected to the processing chamber 9, and the interior of the processing chamber 9 is maintained at a suitable gas atmosphere and pressure for processing. A sample stage 11 for placing the object to be processed, i.e., a wafer 10, is provided inside the processing chamber 9.

[0025] Meanwhile, an electromagnetic coil (not shown) surrounding the cylindrical cavity 7 and the processing chamber 9 forms a magnetic field strength surface of 0.0875 Tesla, which induces electron cyclotron resonance in the processing chamber 9 and forms plasma in the material gas supplied from the aforementioned gas introduction system.

[0026] exist Figure 2 The details of the mode converter 5 are shown. The two openings 20 and 21 of the T-shaped circulator 12, located closest to the power supply side and having a bias magnetic field application section (e.g., a microwave ferrite with a bias magnetic field applied by a permanent magnet) on the waveguide, are connected to the two openings at angle E 13a. (From...) Figure 2 As is known, the two E-angles 13a are symmetrically arranged. Further down from the E-angles 13a, two E-angles 13b are connected, and then two E-angles 14 are connected, so that they are sandwiched between the E-angles 13a and 13b. The E-angles 13a, 13b, and 14 are collectively referred to as the impedance matching section.

[0027] A cylindrical waveguide 16 is connected to the lower part (processing chamber side) of angle E 14. Inside the cylindrical waveguide 16 is a metallic, tapered, sloping septum 15. A circular polarizer (cylindrical waveguide) with such a septum is called a septum polarizer. Furthermore, Figure 2 The image on the lower left is a side view of the diaphragm polarizer to show the shape of the "sloping diaphragm".

[0028] Furthermore, the two ports (openings) 22 and 23 at the lower part (processing chamber side) of E angle 14 are independently connected to the two ports (openings) 24 and 25 at the upper part (power supply side) of the diaphragm polarizer.

[0029] Furthermore, the circulator 12 does not necessarily have to be T-shaped; it can also be Y-shaped, etc. Additionally, the aforementioned bias magnetic field application unit can use an electromagnet (electromagnetic coil) instead of a permanent magnet to electrically switch the direction of the circularly polarized wave described later. Moreover, as for the microwave ferrite material, it is desirable to select a material with the lowest possible loss at the operating frequency. However, circulators with practically low loss (around 0.1 dB insertion loss at 2.45 GHz) are already available on the market; therefore, it is appropriate to select and use one of these.

[0030] Furthermore, in this embodiment, the mode converter 5 is configured as a symmetrical structure. However, as long as the impedance between the circulator 12 and the diaphragm polarizer is matched, the waveguide lengths of E angles 13a and 13b can be arbitrarily determined. Under the same constraints, H angles, bends, coaxial cables, etc. can also be used to replace E angles 13a and 13b.

[0031] Here, we will explain the diaphragm polarizer. Diaphragm polarizers are known as one of the units for generating circularly polarized waves, as described, for example, on page 111 of "Fundamentals of Circularly Polarized Wave Antennas" (by Takeshi Fukusako, Corona Corporation, 2018). Therefore, although only an example of a stepped diaphragm is described, in non-wideband applications, a simpler sloping diaphragm shape can simplify the shape optimization process during design. Of course, the diaphragm shape can also be set to stepped or other shapes as needed.

[0032] As a property of the diaphragm polarizer, the sense (direction of electric field rotation, right-handed or left-handed) of the circularly polarized wave can be determined by which of the two ports divided by the diaphragm from which microwaves are introduced. In this embodiment, it is configured to transform the traveling wave FW from the circulator 12 into a right-handed circularly polarized wave. However, it can also be configured to transform it into a left-handed circularly polarized wave by flipping either the circulator 12 or the ramp-shaped diaphragm 15. The dimensions of each part of the diaphragm polarizer can use known dimensions, or they can be determined using electromagnetic field simulation software such as HFSS (full-wave three-dimensional electromagnetic field software).

[0033] Furthermore, the diaphragm polarizer also has the property of determining which port the microwave propagates to based on the direction of rotation of the microwave from the cylindrical waveguide. In this embodiment, since the lower part of the cylindrical cavity 7 has an axisymmetric structure, the direction of rotation of the reflected wave RW from the processing chamber side is reversed relative to the traveling wave FW. Therefore, the reflected wave RW propagates in a path other than the path of the traveling wave FW. It is worth noting that the direction of rotation of the circularly polarized wave is defined based on the direction of wave propagation. In addition, in general plasma processing apparatuses, the periphery of the processing chamber often has an axisymmetric structure for uniform processing, and the premise of the aforementioned axisymmetric structure is not particularly limited to this embodiment.

[0034] However, the reason for the generation of elliptically polarized waves, a current problem, is that the reflected microwave wave RW from the processing chamber 9 is converted into a circularly polarized wave with opposite directions of rotation inside the mode converter 5 and then re-injected. The circularly polarized waves with different directions of rotation mix and propagate towards the processing chamber side. But in this embodiment, as... Figure 2 As shown, the reflected wave RW propagating from the processing chamber side to the circulator 12 returns to the power supply side without being reflected again inside the mode converter 5 (see reference). Figure 2 (Top right view of the modulus converter).

[0035] The microwaves returning to the power supply side are pushed back by the matching unit 4 and propagate again as traveling waves (FW) in the path shown in the diagram. Therefore, waves with a different rotation direction than desired do not propagate towards the processing chamber side, and the mixing of waves with different rotation directions does not cause a deterioration in the uniformity of the electric field distribution. Furthermore, the components of the mode converter 5 do not contain elements such as dummy loads that actively lose microwave energy; all components have sufficiently low losses for practical use. Therefore, this energy can be effectively utilized in plasma generation.

[0036] However, this is predicated on adequate impedance matching between the circulator 12 and the diaphragm polarizer. This is because if mismatch causes reflections within the impedance matching sections at E angles 13a, 13b, and 14, in the case of a reflected wave (RW), the microwave propagates directly to the other port on the upper part of the diaphragm polarizer; in the case of a traveling wave (FW), the microwave propagates through the circulator 12 to the other port on the upper part of the diaphragm polarizer, preventing the generation of circularly polarized waves with opposite directions of rotation. To avoid this situation, in this embodiment, impedance matching is performed for the operating frequency, 2.45 GHz, by adjusting the width and length of the rectangular waveguide at E angle 14.

[0037] In this embodiment, even in the case of an axisymmetrically distributed static magnetic field applied inside the processing chamber 9, such as in an ECR plasma processing apparatus, to the extent that it causes electron cyclotron resonance, the same effect can be obtained. In this case, due to the anisotropy of the dielectric constant of the magnetized plasma, the reflection characteristics from the processing chamber side change according to the rotation direction of the circularly polarized wave. Although it is indeed possible that the magnitude of the reflection varies according to the rotation direction, the reflected wave RW is a left-handed circularly polarized wave when the traveling wave FW is a right-handed circularly polarized wave, and vice versa, so the anisotropy mentioned above is not changed. Therefore, the homogenization effect of this embodiment can also be obtained in an ECR plasma processing apparatus.

[0038] As a further effect of this embodiment, the system structure is simple since no feedback control system is used, and there is virtually no response time. In addition, there is no need for movable parts such as an electric field sensor for monitoring the axial ratio (an indicator of the degree of mixing of rotational directions) of circularly polarized waves or an actuator for adjusting the characteristics of the mode converter 5.

[0039]

Example 2

[0040] Other embodiments of the analog-to-digital converter 5 are described. Figure 3 The detailed construction of the mode converter 5 involved in Embodiment 2 is shown. Microwaves from the matching unit 4 are vertically bent by a square-to-circular converter 32, maintaining the angle of the polarization plane (the plane parallel to the propagation direction and the electric field direction) unchanged, and propagate towards the Faraday rotor 33. The Faraday rotor 33 is a stepped cylindrical waveguide 37 containing a ferrite rod 34 and its support 35 internally and a coil 36 externally for applying a bias magnetic field to the ferrite rod 34. Through the Faraday effect, the polarization plane of the linearly polarized wave is rotated 45° in a vertically downward right-handed helical direction. Figure 3 As shown in the right figure, the quarter-wavelength plate 38 disposed within the cylindrical waveguide 39 is composed of a quartz plate with upper and lower rectangular cutouts, as in... Figure 4As explained, the long side, when viewed from the upper surface, is further tilted by 45° relative to the polarization plane, transforming the linearly polarized wave from the Faraday rotor 33 into a (right-rotating) circularly polarized wave.

[0041] exist Figure 4 This shows the polarization of the waves in each part of the mode converter 5. First, from... Figure 4 The explanation begins with the left figure. The traveling wave FW, transformed from the TE10 mode of the square waveguide to the TE11 mode of the cylindrical waveguide using the square-to-circular converter 32, has an electric field oriented with polarized wave P1a at the upper part of the Faraday rotor 33. Subsequently, the FW, biased by a vertically downward DC magnetic field and passing through the ferrite rod 34, rotates 45° in a vertically downward right-handed spiral direction through the Faraday effect, and the orientation of the electric field at the upper part of the 1 / 4 wavelength plate 38 becomes P2a.

[0042] The quarter-wave plate 38, viewed from above, has a 45° angle relative to P2a, extending vertically downwards in a right-handed spiral direction, thus transforming into a right-handed circularly polarized wave (P3a). Here, in the direction of microwave propagation, if the electric field is clockwise, it is defined as right-handed (right-handed); if the electric field is counter-clockwise, it is defined as left-handed (left-handed). Regarding the FW propagating downwards from the quarter-wave plate 38, a portion of the electric current is reflected below the boundary (load) between the cylindrical waveguide 6 and the cylindrical cavity 7, such as... Figure 4 As shown in the right figure, the reflected wave (RW) returns to the mode converter 5.

[0043] Here, as long as the load is geometrically sufficiently axisymmetric as in this embodiment, when FW is a circularly polarized wave, RW also becomes a circularly polarized wave. Furthermore, if FW is right-handed, then RW is left-handed, and if FW is left-handed, then RW is right-handed; that is, the rotation direction (the direction of electric field rotation) is reversed, resulting in a cross-polarized wave. Additionally, in typical plasma processing apparatuses, the processing chamber is generally designed to be axisymmetric for uniform processing; therefore, the above assumption is not particularly valid in this embodiment.

[0044] The RW wave, now a left-handed circularly polarized wave (P3b), passes through the quarter-wave plate 38 again and is inversely transformed into a linearly polarized wave. However, at this point, the polarized wave P2b of the RW above the quarter-wave plate 38 also becomes a cross-polarized wave perpendicular to P2a. Subsequently, the RW is subjected to Faraday rotation by the ferrite rod 34. However, as is the nature of Faraday rotation, the direction of rotation (clockwise or counterclockwise) is not determined by the microwave's direction of travel, but by the direction of the bias magnetic field. That is, the FW tilts clockwise when observing the microwave's direction of travel, and counterclockwise when observing the microwave's direction of travel (always tilting to the right-handed spiral relative to the bias magnetic field). Therefore, the polarized wave P1b of the RW above the ferrite rod 34 has the same orientation as P1a. This polarized wave can pass through without being reflected by the square-to-circular converter 32 and propagate to the matching unit 4.

[0045] Consider the case without the Faraday rotor 33. In this case, below the square-to-circular converter 32, RW and FW have polarization planes that are 90° out of phase, like P2a and P2b. Furthermore, since the square-to-circular converter 32 preserves the polarization plane angle of the transmitted microwaves, RW propagates in the square waveguide 2 as a TE01 mode with a horizontal polarization plane.

[0046] However, in order to facilitate the handling of microwaves in the microwave source 1, isolator 3, and matching unit 4, for example, if the frequency is 2.45 GHz, the square waveguide 2 is usually designed to be sized so that only the fundamental mode TE10, such as WR-430, can propagate, while the higher-order mode TE01 cannot propagate in the square waveguide 2. Therefore, RW is all reflected again at the square-to-circular converter 32 and re-injected into the cavity as a secondary traveling wave FW´.

[0047] The preservation of the polarization plane of the square-to-circular converter 32 also holds true in the case of reflection. Above the quarter-wave plate 38, the polarization plane of FW' is also orthogonal to RW. Therefore, FW', which is converted into a circularly polarized wave at the lower part of the quarter-wave plate 38, has a rotation direction opposite to that of FW. When circularly polarized waves with different rotation directions coincide in the same direction of travel, the electric field vector draws an elliptical orbit, hence the name elliptically polarized wave. The higher the degree of mixing of the rotation directions of the elliptically polarized wave, the lower the axial symmetry of the electric field distribution. That is, without the Faraday rotor 33, the larger the RW / FW ratio (reflection coefficient), the larger FW', and the lower the axial symmetry due to the increased degree of mixing of rotation directions.

[0048] On the other hand, with the Faraday rotor 33 present, FW' is absent or sufficiently small, thus suppressing the influence of the RW / FW ratio on symmetry. The RW / FW ratio varies, for example, not only depending on the structure of the cylindrical cavity 7, the microwave inlet window 8, and the processing chamber 9, but also on processing conditions such as the gas used in processing, the pressure within the processing chamber, and the power supplied to the microwaves. That is, the axisymmetry of the electric field distribution generated by the mode converter 5 does not depend on the RW / FW ratio, enabling uniform processing under a wider range of conditions.

[0049] Furthermore, in the case without Faraday rotor 33, FW´ is reflected from the load as RW´, similar to the case with FW. However, since the polarization plane angles of RW´ and FW are the same in the square-to-circular converter 32, it can pass through the square waveguide 2 as TE10 mode and return to the matching unit 4. Therefore, RW´ does not affect the axisymmetry of the electric field distribution in the processing chamber.

[0050] The above discussion assumes that there is no microwave reflection or sufficiently small microwave reflection at the interface between the Faraday rotor 33 and the quarter-wavelength plate 38, i.e., impedance matching is performed. In the aforementioned discussion, if this premise is not simultaneously met, the axisymmetry of the electric field distribution ultimately changes according to the RW / FW ratio.

[0051] Therefore, in this embodiment, a cylindrical stepped waveguide 37 is used in the Faraday rotor 33 to meet this premise, and the diameter and length of the steps are adjusted to minimize reflection at the interface at the applied power frequency. Furthermore, the outer diameter, thickness, and dimensions of the upper and lower notches of the quarter-wavelength plate 38 are also adjusted in the same way.

[0052] To ensure efficient transfer of microwave power to the processing chamber using the mode converter 5, internal losses must be minimized. Therefore, the ferrite rod 34 utilizes a low-loss material such as garnet-type ferrite based on YIG (yttrium iron garnet). Furthermore, the support 35 uses PTFE with a low dielectric loss tangent. While the ferrite rod 34 and support 35 are fixed by press-fitting, if adhesive is used, a low dielectric loss tangent adhesive such as a polyimide adhesive is preferred. Moreover, when using high power, not only is high power efficiency required, but care must also be taken to prevent overheating of the ferrite rod 34. If the allowable temperature is exceeded, additional cooling mechanisms may be necessary.

[0053] The cylindrical waveguide 39 with the quarter-wavelength plate 38 is generally a type of "waveguide polarizer" (refer to Non-Patent Document 1). However, any waveguide polarizer has the same structure as this embodiment. When converting a linearly polarized wave into a circularly polarized wave, it has the property that if the electric field orientations of the linearly polarized waves differ by 90°, the rotation direction of the output circularly polarized wave will be reversed. Conversely, when converting a circularly polarized wave into a linearly polarized wave, it has the property that the electric field orientation of the output linearly polarized wave changes by 90° depending on the rotation direction of the input circularly polarized wave. Therefore, the structure is not limited to this embodiment, and the same effect can be obtained by using any waveguide polarizer.

[0054] As described above, this embodiment utilizes the fact that by setting the rotation angle of the Faraday rotor 33 to 45°, the waves transmitted twice in both the vertical and horizontal directions are subjected to a total rotational effect of 90°. More generally, if the Faraday rotation angle is set to θ = 90° × n + 45° (where n is any integer), then the waves transmitted twice in both directions through the Faraday rotor 33 are subjected to a total rotational effect of 2θ = 180° × n + 90°. Here, for a rotation of 180° × n, since the polarization plane remains unchanged, the same effect can be obtained for any n. However, in order to increase the absolute value of the rotation angle, changes such as making the ferrite rod 34 longer are required. Unless there is a particular reason, it is desirable in the design to set |θ| = 45°.

[0055] Due to the axial symmetry of the electric field, right-handed and left-handed circularly polarized waves are equivalent. Therefore, in this embodiment, it is also possible to configure the structure so that the 1 / 4 wavelength plate 38 is rotated 90° around the vertical axis center to transform into a left-handed rather than right-handed circularly polarized wave. Alternatively, it is also possible to configure the structure as follows: the direction of the current in the coil 36 is reversed to reverse the direction of the bias magnetic field applied to the ferrite rod 34. Taking advantage of the fact that the absolute value of the Faraday rotation angle remains unchanged while only the sign changes, the mode converter 5 outputs a left-handed circularly polarized wave; or, the direction of the current can be arbitrarily switched to appropriately distinguish between right-handed and left-handed polarization.

[0056] In this embodiment, since the plasma in the processing chamber 9 contained in the load is magnetized, its dielectric constant is anisotropic. Generally, for such anisotropic loads, not only does the magnitude and phase of the load's impedance differ depending on the polarization state of the incident microwaves, which include linearly polarized waves and elliptically polarized waves, but the transition from the incident wave to the reflected wave in the polarized wave state can also exhibit behavior different from that of isotropic loads. However, as long as the magnetized plasma has a magnetic field vector symmetrical to the central axis of the processing chamber, similarly to the case without a magnetic field, if FW is a right-handed circularly polarized wave, then RW is a left-handed circularly polarized wave, and if FW is a left-handed circularly polarized wave, then RW is a right-handed circularly polarized wave. That is, the premise of this embodiment remains unchanged, therefore, the homogenization effect of this embodiment can also be obtained in the ECR plasma processing apparatus.

[0057] As a further effect of this embodiment, the system structure is simple by not using a feedback control system, there is virtually no response time, and there is no need for movable parts such as an electric field sensor for monitoring the axial ratio (an indicator of the degree of mixing of rotational directions) of circularly polarized waves or an actuator for adjusting the characteristics of the mode converter 5.

[0058] Explanation of reference numerals in the attached figures

[0059] 1…Microwave source, 2…Square waveguide, 3…Isolator, 4…Matcher, 5…Mode converter, 6…Cylindrical waveguide, 7…Cylindrical cavity, 8…Microwave inlet window, 9…Processing chamber, 10…Wafer, 11…Sample stage, 12…Circulator, 13a, 13b…E-angle, 14…E-angle, 15…Diaphragm, 16…Cylindrical waveguide, 32…Square-to-circular converter, 33…Faraday rotor, 34…Ferrite rod, 35…Support, 36…Coil, 37…Cylindrical stepped waveguide, 38…1 / 4 wavelength plate, 39…Cylindrical waveguide, FW…Traveling wave, RW…Reflected wave.

Claims

1. A plasma processing apparatus, comprising: The processing chamber is where samples undergo plasma treatment. A high-frequency power supply that provides high-frequency power to microwaves via a matching unit; A magnetic field forming mechanism that forms a magnetic field in the processing chamber; and A sample stage on which the sample is placed. The plasma processing device is characterized in that it further comprises: A diaphragm polarizer converts the microwaves propagating via a circulator into circularly polarized waves. The first port of the circulator is connected to the high-frequency power supply via the matching unit. The second port of the circulator is connected to one port of the diaphragm polarizer via an impedance matching section. The third port of the circulator is connected to the other port of the diaphragm polarizer via an impedance matching section. The microwave propagating to the port of said one side is transformed into a right-hand circularly polarized wave. The microwave propagating to the port of the other party is transformed into a left-handed circularly polarized wave. The impedance matching section includes a rectangular waveguide. The width and length of the rectangular waveguide are specified to ensure impedance matching of the propagating microwaves.

2. The plasma treatment apparatus according to claim 1, wherein, Ferrite is disposed in the waveguide of the circulator.

3. The plasma treatment apparatus according to claim 1, wherein, An electromagnet is disposed in the waveguide of the circulator.

4. The plasma treatment apparatus according to claim 1, wherein, The traveling wave propagating from the circulator propagates toward one of the ports.

5. The plasma treatment apparatus according to claim 1, wherein, The diaphragm polarizer uses a metal diaphragm to divide its interior.

6. The plasma treatment apparatus according to claim 1, wherein, The microwave is a 2.45 GHz microwave.

7. A plasma processing apparatus, comprising: The processing chamber is where samples undergo plasma treatment. A high-frequency power supply that provides high-frequency power to microwaves via a matching unit; A magnetic field forming mechanism that forms a magnetic field in the processing chamber; and A sample stage on which the sample is placed. The plasma processing device is characterized in that it further comprises: A Faraday rotor, which, when n is set to an integer, rotates the phase of the polarization plane of a linearly polarized wave propagating via the matched unit by (90 × n + 45) degrees; and A waveguide-type circular polarization converter switches between right-handed and left-handed circular polarization waves whenever the phase of the polarization plane of a linearly polarized wave rotating through the Faraday rotor changes by 90 degrees. The waveguide-type circular polarization wave converter is positioned between the Faraday rotor and the processing chamber. Impedance matching is performed between the Faraday rotor and the waveguide-type circular polarization wave converter.

8. The plasma treatment apparatus according to claim 7, wherein, The Faraday rotor has components made of garnet-type ferrite.

9. The plasma treatment apparatus according to claim 7, wherein, The Faraday rotor has a stepped cylindrical waveguide.

10. The plasma treatment apparatus according to claim 7, wherein, The waveguide-type circular polarization wave converter has a 1 / 4 wavelength plate.

11. The plasma processing apparatus according to claim 10, wherein, The 1 / 4 wavelength plate is a cuboid quartz plate with rectangular notches at the top and bottom along its long side.

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