Plasma processing device

Abstract

The purpose of the present invention is to provide a plasma processing device for supplying radicals to a substrate.　This plasma processing device includes: a processing container; a placement table provided in the processing container; a top wall and a side wall that define a plasma formation space in the processing container; and a plurality of electrode pairs that are provided on the side wall and to which high-frequency power is supplied.

Description

Plasma processing equipment

[0001] The present disclosure relates to a plasma processing apparatus.

[0002] Patent Document 1 discloses a film forming apparatus that includes an ion trapping member for trapping ions contained in a plasma-converted processing gas formed in a plasma generation space, and supplies high-density radicals from the plasma-converted processing gas to a substrate.

[0003] JP 2023-58371 A

[0004] In one aspect, the present disclosure provides a plasma processing apparatus for supplying radicals to a substrate.

[0005] In order to solve the above problem, according to one aspect, a plasma processing apparatus is provided, comprising: a processing vessel; a mounting table provided within the processing vessel; a ceiling wall and a side wall that partition a plasma generation space within the processing vessel; and a plurality of electrode pairs provided on the side wall to which high-frequency power is supplied.

[0006] According to one aspect, a plasma processing apparatus can be provided that supplies radicals to a substrate.

[0007] 1. An example of a vertical cross-sectional view of a plasma processing apparatus according to a first embodiment. A schematic view of an electrode pair viewed from above the plasma processing apparatus and an example of a configuration diagram of a high-frequency supply unit. An example of high-frequency power applied to the electrodes. An example of a vertical cross-sectional view of a plasma processing apparatus according to a second embodiment. An example of a vertical cross-sectional view of a plasma processing apparatus according to a third embodiment. An example of a vertical cross-sectional view of a plasma processing apparatus according to a fourth embodiment. An example of a vertical cross-sectional view of a plasma processing apparatus according to a fifth embodiment. A schematic view of an electrode pair viewed from above the plasma processing apparatus and an example of a configuration diagram of a high-frequency supply unit. An example of high-frequency power applied to the electrodes. An example of high-frequency power applied to the electrodes. An example of a schematic view of electrodes viewed from above the plasma processing apparatus. An example of a schematic view showing the arrangement of electrodes by developing the cylindrical surface of a side wall. An example of a horizontal cross-sectional view showing the structure of the side wall and the electrodes.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] [Plasma Processing Apparatus 1 According to First Embodiment] A plasma processing apparatus 1 according to a first embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is an example of a longitudinal cross-sectional view of the plasma processing apparatus 1 according to the first embodiment. The plasma processing apparatus 1 is a substrate processing apparatus that generates plasma P of a processing gas, supplies radicals from the plasma-converted processing gas to a substrate Wf such as a semiconductor wafer, and performs a desired process (e.g., a film formation process, an etching process, etc.) on the substrate Wf. For example, the plasma processing apparatus 1 may be configured as an apparatus that reacts a source gas containing a film precursor with a reactive gas, which is a plasma-converted processing gas, to form a film on the substrate Wf by PEALD (Plasma Enhanced Atomic Layer Deposition). However, the plasma processing apparatus 1 is not limited thereto and may also be configured as an apparatus that forms a film on the substrate Wf by PECVD (Plasma Enhanced Chemical Vapor Deposition). The plasma processing apparatus 1 may also be an etching apparatus.

[0010] The plasma processing apparatus 1 includes a substantially cylindrical airtight processing chamber 2 , a mounting table 3 , and a gas supply unit 4 .

[0011] The processing vessel 2 is a grounded, metallic, approximately cylindrical vessel. The processing vessel 2 has a processing space 21 and a plasma generation space 22 therein. The processing space 21 is a space where a mounting table 3 supporting a substrate Wf is disposed. The plasma generation space 22 is a space where a plasma P of a processing gas, described later, is generated. The processing space 21 and the plasma generation space 22 are connected to each other. The processing vessel 2 has an intermediate wall 23 and a side wall 24 therein. The intermediate wall 23 has an annular shape with an opening in the center and divides the interior of the processing vessel 2 into an upper space and a lower space. The lower space within the processing vessel 2, divided by the intermediate wall 23, is the processing space 21. The intermediate wall 23 is also made of metal and is grounded. The side wall 24, which is a cylindrical insulator, is disposed on the intermediate wall 23. A shower head 41, described later, is disposed on the side wall 24. The upper space within the processing vessel 2, which is partitioned by the intermediate wall 23 and which is also partitioned by the sidewall 24 and the shower head 41, becomes the plasma generation space 22. That is, the sidewall 24 serves as a side wall of the plasma generation space 22, thereby partitioning the plasma generation space 22 within the processing vessel 2. The shower head 41 serves as a ceiling wall of the plasma generation space 22, thereby partitioning the plasma generation space 22 within the processing vessel 2. A seal member 91 seals the gap between the shower head 41 and the sidewall 24. A seal member 93 seals the gap between the intermediate wall 23 and the sidewall 24.

[0012] An exhaust port 29 to which an exhaust device 80 is connected is provided on the bottom wall of the processing vessel 2 on the processing space 21 side. The exhaust device 80 reduces the pressure in the processing space 21 and the plasma generation space 22 to a predetermined level.

[0013] The mounting table 3 is provided in the processing space 21 and holds the substrate Wf in a substantially horizontal position.

[0014] The gas supply unit 4 has a shower head 41. The shower head 41 is made of a conductor such as a metal. The process gas supplied from the gas supply source 40 to the shower head 41 is supplied from the shower head 41 into the plasma generation space 22.

[0015] A plurality of electrode pairs 51 are provided on the sidewall 24 of the plasma generating space 22. The gap between the sidewall 24 and the electrode pairs 51 is sealed with a sealing member 92. High-frequency power for generating plasma P is supplied to the electrode pairs 51 from a high-frequency power supply unit 60. This generates capacitively coupled plasma in the plasma generating space 22. In the example shown in FIG. 1 , one electrode pair 51 is composed of an electrode 51 a and an electrode 51 d. A plurality of electrode pairs 51 are provided in the circumferential direction of the sidewall 24 (see FIG. 2 , described later). The electrode pairs 51 face each other in a direction perpendicular (i.e., horizontal) to the normal (i.e., vertical) to the substrate mounting surface of the mounting table 3. In other words, a line connecting the center of one electrode 51 a to the center of the other electrode 51 d of each electrode pair 51 is parallel (or approximately parallel) to the processing surface (top surface) of the substrate Wf mounted on the mounting table 3. Here, the line connecting the centers of the electrodes 51 a and 51 d and the processing surface of the substrate Wf being substantially parallel to each other preferably forms an angle within a range of −22° to +22°. Further, high frequency power for generating plasma P is supplied to the electrode pair 51 from the high frequency supply unit 60.

[0016] 2 is a schematic diagram of the electrode pairs 51 as viewed from above the plasma processing apparatus 1 and an example of a configuration diagram of the high frequency supply unit 60. Here, an example of a configuration including three sets of electrode pairs 51 will be described.

[0017] A plurality of electrodes 51a to 51f are provided on the sidewall 24. The electrodes 51a to 51f are arranged at equal intervals in the circumferential direction of the sidewall 24. The electrodes 51a to 51f are arranged to surround the substrate Wf placed on the mounting table 3. The electrodes 51a and 51d are arranged opposite each other in the horizontal direction to form one electrode pair 51. The electrodes 51b and 51e are arranged opposite each other in the horizontal direction to form one electrode pair 51. The electrodes 51c and 51f are arranged opposite each other in the horizontal direction to form one electrode pair 51. In the following description, the electrode 51a will be referred to as the U-phase, the electrode 51d opposite the electrode 51a as the U'-phase, the electrode 51c as the V-phase, the electrode 51f opposite the electrode 51c as the V'-phase, the electrode 51e as the W-phase, and the electrode 51b opposite the electrode 51e as the W'-phase.

[0018] 2, the electrodes 51a to 51f are illustrated as having an arc shape, but the shape of the electrodes 51a to 51f is not limited to this. The electrodes 51a to 51f may also be configured to have a flat plate shape.

[0019] 1 and 2, high-frequency power for generating plasma P is supplied from a high-frequency supply unit 60 to one of the electrodes 51a, 51c, and 51e of the electrode pair 51. The other of the electrodes 51b, 51d, and 51f of the electrode pair 51 is grounded.

[0020] The high frequency supply unit 60 has a phase controller 61 and RF supply units 62 to 64. The number of RF supply units 62 to 64 is the same as the number of electrode pairs 51 (three pairs). The RF supply unit 62 has a high frequency power supply 621 and an impedance matching box 622. The frequency of the high frequency power supply 621 is, for example, 400 kHz to 100 MHz. Both ions and radicals are generated in the plasma P generated using this frequency. Like the RF supply unit 62, the RF supply units 63 and 64 also have a high frequency power supply (not shown) and an impedance matching box (not shown).

[0021] The RF supply unit 62 supplies high-frequency power to the U-phase electrode 51a. That is, the high-frequency power source 621 of the RF supply unit 62 supplies high-frequency power to the electrode 51a via an impedance matching box 622. Similarly, the RF supply unit 63 supplies high-frequency power to the V-phase electrode 51c. Furthermore, the RF supply unit 64 supplies high-frequency power to the W-phase electrode 51e.

[0022] The phase controller 61 controls the high frequency power supplies of the RF supply units 62 to 64 to control the phases of the high frequency power supplied from the RF supply units 62 to 64 to the electrodes 51a, 51c, 51e (U phase, V phase, W phase).

[0023] 3 shows an example of high-frequency power applied to the electrodes 51a, 51c, and 51e. High-frequency powers are supplied to the electrodes 51a, 51c, and 51e, each with a phase difference of 120°. Specifically, a first high-frequency power (U-phase) is supplied to one electrode 51a of the first electrode pair 51, and the other electrode 51d of the first electrode pair 51 is grounded. A second high-frequency power (V-phase) that is 120° out of phase with the first high-frequency power (U-phase) is supplied to one electrode 51c of the second electrode pair 51, and the other electrode 51f of the second electrode pair 51 is grounded. A third high-frequency power (W-phase) that is 240° out of phase with the first high-frequency power (U-phase) is supplied to one electrode 51e of the third electrode pair 51, and the other electrode 51b of the third electrode pair 51 is grounded.

[0024] In this way, by arranging multiple electrodes 51a to 51f at equal intervals around the circumferential direction of the side wall 24 and supplying high-frequency power with a phase shift of 120°, the circumferential uniformity of the plasma P formed in the plasma generation space 22 is improved.

[0025] Although the number of electrode pairs 51 is three in the above example, the present invention is not limited to this.

[0026] For example, the plasma processing apparatus 1 may be configured to include two pairs of electrodes. In this case, high-frequency powers are supplied to the respective electrodes with a phase difference of 180°. Specifically, a first high-frequency power is supplied to one electrode of a first electrode pair, and the other electrode of the first electrode pair is grounded. A second high-frequency power, which is 180° out of phase with the first high-frequency power, is supplied to one electrode of a second electrode pair, and the other electrode of the second electrode pair is grounded.

[0027] The plasma processing apparatus 1 may also be configured to include n sets of electrode pairs (n is an integer of 2 or greater). In this case, high-frequency power is supplied to one electrode of each of the n sets of electrode pairs, with the phases shifted by 360° / n. The other electrode of each of the n sets of electrode pairs is grounded. Increasing the number of electrode pairs further improves the circumferential uniformity of the plasma P formed in the plasma generation space 22.

[0028] Furthermore, in the n sets of electrode pairs (n is an integer of 3 or more), it is preferable that one electrode to which high-frequency power is supplied and the other electrode to which grounding is performed be alternately arranged in the circumferential direction of the side wall 24. This improves the uniformity of the plasma P formed in the plasma generation space 22 in the circumferential direction.

[0029] Returning to FIG. 1 , the showerhead 41 is grounded via an impedance control circuit (first impedance control circuit) 71. The impedance control circuit 71 includes, for example, a variable capacitor, an inductor, etc., and controls the impedance so that the showerhead 41 has a high impedance relative to the frequency of the high-frequency power applied to the electrodes 51a, 51c, and 51e. As a result, with respect to the high-frequency power applied to the electrodes 51a, 51c, and 51e, the showerhead 41 is electrically floating relative to the electrodes 51b, 51d, and 51f, which are at ground potential. This prevents the showerhead 41, which forms the ceiling wall of the plasma generation space 22, from being considered to be at ground potential. In other words, the electrodes 51a to 51f provided on the sidewall 24 form an opposing electrode pair 51.

[0030] The mounting table 3 is also grounded via an impedance control circuit (third impedance control circuit) 72. The impedance control circuit 72 includes, for example, a variable capacitor, an inductor, etc., and controls the impedance so that the mounting table 3 has a high impedance with respect to the frequency of the high-frequency power applied to the electrodes 51 a, 51 c, and 51 e. As a result, with respect to the high-frequency power applied to the electrodes 51 a, 51 c, and 51 e, the mounting table 3 is electrically floating relative to the electrodes 51 b, 51 d, and 51 f, which are at ground potential. This prevents ions in the plasma P generated in the plasma generation space 22 from being attracted by the potential of the mounting table 3. In other words, ions in the plasma P are prevented from being attracted to the substrate Wf.

[0031] Here, a plasma processing apparatus according to a reference example will be described. The plasma processing apparatus according to the reference example uses a lower electrode provided on the mounting table 3 and an upper electrode (shower head 41) vertically facing the lower electrode as an electrode pair, and generates CCP plasma by supplying high-frequency power to the upper electrode or the lower electrode. In the plasma processing apparatus according to the reference example, ions moving in the vertical direction are generated. Therefore, when the substrate Wf is exposed to plasma, ions may be incident on the substrate Wf and damage the substrate Wf. Furthermore, ion damage may degrade the characteristics of semiconductor devices formed on the substrate Wf.

[0032] In contrast, in the plasma processing apparatus 1 according to the first embodiment, the electrode pair 51 for supplying high-frequency power for plasma generation is provided on the sidewall 24 of the plasma generation space 22, and the electrode pair 51 is arranged so as to face each other horizontally, thereby suppressing ions moving in the vertical direction. This suppresses ions from being incident on the substrate Wf, thereby preventing deterioration of the characteristics of the semiconductor device formed on the substrate Wf. Meanwhile, radicals in the plasma P diffuse from the plasma generation space 22 to the processing space 21 and are supplied to the substrate Wf. This allows radicals to be supplied to the substrate Wf, enabling the substrate Wf to be subjected to the desired processing.

[0033] 1 has been described as an example of a plasma processing apparatus 1 that supplies radicals to the substrate Wf, but the present invention is not limited to this. In a plasma processing apparatus 1 that supplies radicals and ions to the substrate Wf, the impedance control circuit 72 may be omitted and the mounting table 3 may be grounded. This allows radicals to be supplied to the substrate Wf, and ions in the plasma P to be attracted to the substrate Wf to supply ions to the substrate Wf.

[0034] [Plasma Processing Apparatus 1A According to Second Embodiment] The plasma processing apparatus 1A according to the second embodiment will be described with reference to FIG. 4. FIG. 4 is an example of a longitudinal cross-sectional view of the plasma processing apparatus 1A according to the second embodiment. The plasma processing apparatus 1A according to the second embodiment (see FIG. 4) differs from the plasma processing apparatus 1 according to the first embodiment (see FIG. 1) in the structure that divides the plasma generation space 22. The remaining structures are similar, and therefore redundant explanations will be omitted.

[0035] The processing vessel 2 has an intermediate wall 23, a side wall 24, an insulating member 25, and a lower shower head 42 therein. The intermediate wall 23 has a circular ring shape with an opening in the center, and divides the interior of the processing vessel 2 into an upper space and a lower space. The lower space within the processing vessel 2 divided by the intermediate wall 23 serves as the processing space 21. The intermediate wall 23 is made of metal and is grounded. A lower shower head 42 is disposed in the opening of the intermediate wall 23 via an insulating member 25. The lower shower head 42 has multiple through-holes that extend from the plasma generation space 22 to the processing space 21 and is made of a conductor such as metal. The side wall 24, which is made of a cylindrical insulator, is disposed on the insulating member 25. A shower head 41 is disposed on the side wall 24. The upper space within the processing vessel 2 divided by the intermediate wall 23 and that is divided by the side wall 24, the shower head 41, and the lower shower head 42 serves as the plasma generation space 22. That is, the sidewall 24 serves as a sidewall of the plasma generation space 22, partitioning the plasma generation space 22 within the processing vessel 2. The shower head 41 serves as a ceiling wall of the plasma generation space 22, partitioning the plasma generation space 22 within the processing vessel 2. The lower shower head 42 serves as a bottom wall of the plasma generation space 22, partitioning the plasma generation space 22 within the processing vessel 2. A seal member 91 seals between the shower head 41 and the sidewall 24. A seal member 93 seals between the intermediate wall 23 and the insulating member 25. A seal member 94 seals between the insulating member 25 and the sidewall 24.

[0036] The lower shower head 42 is also grounded via an impedance control circuit (second impedance control circuit) 73. The impedance control circuit 73 includes, for example, a variable capacitor, an inductor, or the like, and controls the impedance so that the lower shower head 42 has a high impedance relative to the frequency of the high-frequency power applied to the electrodes 51a, 51c, and 51e. As a result, with respect to the high-frequency power applied to the electrode 51a, the lower shower head 42 is electrically floating relative to the electrodes 51b, 51d, and 51f, which are at ground potential. This prevents the lower shower head 42, which forms the bottom wall of the plasma generation space 22, from being considered to be at ground potential. In other words, the electrodes 51a to 51f provided on the side wall 24 can form an opposing electrode pair 51.

[0037] As described above, in the plasma processing apparatus 1A according to the second embodiment, the electrode pair 51 for supplying high-frequency power for plasma generation is provided on the sidewall 24 of the plasma generation space 22, and the electrode pair 51 is arranged so as to face each other horizontally, thereby suppressing ions moving in the vertical direction. This suppresses ions from being incident on the substrate Wf, thereby preventing deterioration of the characteristics of semiconductor devices formed on the substrate Wf. Meanwhile, radicals in the plasma P diffuse from the plasma generation space 22 to the processing space 21 and are supplied to the substrate Wf. This allows radicals to be supplied to the substrate Wf, enabling the substrate Wf to be subjected to the desired processing.

[0038] [Plasma Processing Apparatus 1B According to Third Embodiment] The plasma processing apparatus 1B according to the third embodiment will be described with reference to FIG. 5. FIG. 5 is an example of a vertical cross-sectional view of the plasma processing apparatus 1B according to the third embodiment. The plasma processing apparatus 1B according to the third embodiment (see FIG. 5) differs from the plasma processing apparatus 1A according to the second embodiment (see FIG. 4) in the structure for supplying film formation gas. The remaining structures are similar, and therefore, redundant explanations will be omitted.

[0039] A plurality of pipes 46 are arranged in the openings of the intermediate wall 23. The pipes 46 are made of a conductor such as metal and are grounded together with the intermediate wall 23. A film forming gas is supplied to the pipes 46 from a gas supply source 45, and the film forming gas is supplied to the processing space 21 from outlet holes 47. In addition, openings 48 are formed between the pipes 46, which connect the plasma generation space 22 and the processing space 21.

[0040] Here, an example will be described in which a film is formed on a substrate Wf by PEALD.

[0041] First, the control unit controls the gas supply source 45 to supply the film forming gas (precursor gas, second gas) from the discharge holes 47 into the processing space 21 (first step). For example, the film forming gas is adsorbed onto the surface of the substrate Wf.

[0042] Next, the control unit controls the gas supply source 40 to supply a reactive gas (first gas) from the shower head 41 to the plasma generation space 22. The control unit also controls the high-frequency supply unit 60 to supply high-frequency power to the electrode pair 51. This generates a plasma P of the reactive gas in the plasma generation space 22 (second process). The plasma P contains radicals and ions. The radicals diffuse from the plasma generation space 22 through the through-holes and openings 48 of the lower shower head 42 and into the processing space 21. This supplies the reactive gas radicals to the substrate Wf. The film formation gas adsorbed on the surface of the substrate Wf reacts with the reactive gas radicals, forming a film on the surface of the substrate Wf. The process of supplying the film formation gas and the process of generating the reactive gas plasma P constitute one cycle, and this cycle is repeated a predetermined number of times to form a film of a desired thickness on the substrate Wf.

[0043] On the other hand, the vertical movement of ions in the plasma P is suppressed by arranging the electrode pair 51, to which high-frequency power is supplied, horizontally opposite each other. That is, the number of ions passing through the through-holes of the lower shower head 42 is suppressed. In addition, a tube 46, which is at ground potential, is arranged below the lower shower head 42. Ions that pass through the through-holes of the lower shower head 42 are attracted to the tube 46, which is at ground potential. That is, ions that pass through the through-holes of the lower shower head 42 are trapped in the tube 46. In this way, the tube 46 functions as an ion trap member. This makes it possible to further reduce ions in the reaction gas supplied to the substrate W. In other words, the tube 46 is an ion trap plate that can supply gas in a shower-like manner.

[0044] As described above, in the plasma processing apparatus 1B according to the third embodiment, the electrode pair 51 for supplying high-frequency power for plasma generation is provided on the sidewall 24 of the plasma generation space 22, and the electrode pair 51 is arranged so as to face each other horizontally, thereby suppressing ions moving in the vertical direction. This suppresses ions from being incident on the substrate Wf, thereby preventing deterioration of the characteristics of semiconductor devices formed on the substrate Wf. Meanwhile, radicals in the plasma P diffuse from the plasma generation space 22 to the processing space 21 and are supplied to the substrate Wf. This allows radicals to be supplied to the substrate Wf, enabling the substrate Wf to be subjected to the desired processing.

[0045] [Plasma Processing Apparatus 1C According to Fourth Embodiment] A plasma processing apparatus 1C according to a fourth embodiment will be described with reference to FIG. 6. FIG. 6 is an example of a vertical cross-sectional view of the plasma processing apparatus 1C according to the fourth embodiment. The plasma processing apparatus 1C according to the fourth embodiment (see FIG. 6) differs from the plasma processing apparatus 1A according to the second embodiment (see FIG. 4) in the shower head 41A and the lower shower head 42A. The remaining structures are the same, and therefore redundant explanations will be omitted.

[0046] The shower head 41A and the lower shower head 42A are made of a dielectric (insulator). Alternatively, the shower head 41A and the lower shower head 42A may be covered with a dielectric (insulator). This allows the shower head 41A and the lower shower head 42A to have high impedance with respect to the frequency of the high-frequency power applied to the electrodes 51a, 51c, and 51e. As a result, the shower head 41A and the lower shower head 42A are electrically floating relative to the electrodes 51b, 51d, and 51f, which are at ground potential, when the high-frequency power is applied to the electrodes 51a, 51c, and 51e. This prevents the shower head 41A and the lower shower head 42A, which form the ceiling and bottom walls of the plasma generation space 22, from being considered to be at ground potential. Therefore, the impedance control circuits 71 and 73 (see FIG. 4) can be omitted.

[0047] 6 illustrates an example of the configuration of the plasma processing apparatus 1A (see FIG. 4) according to the second embodiment, in which the shower head 41A and the lower shower head 42A are made of or covered with a dielectric material. However, this is not limiting. In the configuration of the plasma processing apparatus 1 (see FIG. 1) according to the first embodiment, the shower head 41A may be made of or covered with a dielectric material. In the configuration of the plasma processing apparatus 1B (see FIG. 5) according to the third embodiment, the shower head 41A and the lower shower head 42A may be made of or covered with a dielectric material.

[0048] [Plasma Processing Apparatus 1D According to Fifth Embodiment] A plasma processing apparatus 1D according to a fifth embodiment will be described with reference to FIGS. 7 to 9A and 9B. FIG. 7 is an example of a vertical cross-sectional view of the plasma processing apparatus 1D according to the fifth embodiment. FIG. 8 is a schematic view of the electrode pair 51 as seen from above the plasma processing apparatus 1D, and an example of a configuration diagram of the high-frequency supply unit 60. The plasma processing apparatus 1D according to the fifth embodiment (see FIGS. 7, 8, 9A, and 9B) differs from the plasma processing apparatus 1B according to the third embodiment (see FIGS. 5, 2, and 3) in the high-frequency power supplied to the electrodes 51a to 51f. The remaining structures are similar, and redundant description will be omitted.

[0049] 8, a plurality of electrodes 51a to 51f are provided on the sidewall 24. The electrodes 51a to 51f are arranged at equal intervals in the circumferential direction of the sidewall 24. The electrodes 51a to 51f are arranged to surround the substrate Wf placed on the mounting table 3. The electrodes 51a and 51d are arranged opposite each other in the horizontal direction to form one electrode pair 51. The electrodes 51b and 51e are arranged opposite each other in the horizontal direction to form one electrode pair 51. The electrodes 51c and 51f are arranged opposite each other in the horizontal direction to form one electrode pair 51. In the following description, the electrode 51a will be referred to as the U-phase, the electrode 51d opposite the electrode 51a as the U'-phase, the electrode 51c as the V-phase, the electrode 51f opposite the electrode 51c as the V'-phase, the electrode 51e as the W-phase, and the electrode 51b opposite the electrode 51e as the W'-phase.

[0050] 8, the electrodes 51a to 51f are illustrated as having an arc shape, but the shape of the electrodes 51a to 51f is not limited to this. The electrodes 51a to 51f may also be configured to have a flat plate shape.

[0051] The high-frequency supply unit 60 has a phase controller 61 and RF supply units 62A to 64A. The number of RF supply units 62A to 64A is the same as the number of electrode pairs 51 (three pairs). The RF supply unit 62A has a high-frequency power supply 621, an impedance matcher 622, a high-frequency power supply 623, and an impedance matcher 624. The frequency of the high-frequency power supplies 621 and 623 is, for example, 400 kHz to 100 MHz. In the plasma P generated using this frequency, both ions and radicals are generated. Like the RF supply unit 62A, the RF supply units 63A and 64A also have two pairs of high-frequency power supplies (not shown) and an impedance matcher (not shown).

[0052] The RF supply unit 62A supplies high-frequency power to the U-phase electrode 51a and the U'-phase electrode 51d. That is, the high-frequency power supply 621 of the RF supply unit 62A supplies high-frequency power to the electrode 51a via an impedance matching device 622. The high-frequency power supply 623 supplies high-frequency power to the electrode 51d via an impedance matching device 624. Here, the high-frequency power supply 623 supplies high-frequency power that is out of phase with the high-frequency power supply 621. Similarly, the RF supply unit 63A supplies high-frequency power to the V-phase electrode 51c and the V'-phase electrode 51f. The RF supply unit 64 supplies high-frequency power to the W-phase electrode 51e and the W'-phase electrode 51b.

[0053] The phase controller 61 controls the high frequency power supplies of the RF supply units 62A to 64A to control the phase of the high frequency power supplied from the RF supply units 62A to 64A to the electrodes 51a, 51c, 51e (U phase, V phase, W phase).

[0054] 9A and 9B show examples of high-frequency power applied to electrodes 51a to 51f. High-frequency power is supplied to electrodes 51a, 51c, and 51e (U-phase, V-phase, and W-phase) with phases shifted by 120° (see FIG. 9A). High-frequency power whose phase is inverted by 180° from the high-frequency power supplied to electrode 51a (U-phase) is supplied to electrode 51d (U'-phase) opposite electrode 51a (see FIG. 9B). High-frequency power whose phase is inverted by 180° from the high-frequency power supplied to electrode 51c (V'-phase) is supplied to electrode 51f (V'-phase) opposite electrode 51c (see FIG. 9B). High-frequency power whose phase is inverted by 180° from the high-frequency power supplied to electrode 51e (W'-phase) is supplied to electrode 51b (W'-phase) opposite electrode 51e (see FIG. 9B).

[0055] As a result, high frequency power is supplied in the order of U phase, W' phase, V phase, U' phase, W phase, and V' phase, with the phases shifted by 60° each.

[0056] In this way, by arranging multiple electrodes 51a to 51f at equal intervals around the circumferential direction of the side wall 24 and supplying high-frequency power with a phase shift of 60°, the circumferential uniformity of the plasma P formed in the plasma generation space 22 is improved.

[0057] Furthermore, by inverting the phase of the high frequency power between the electrode pair 51, it is possible to increase the potential difference between the electrode pair 51. This increases the intensity of the plasma P and increases the number of radicals that are generated. As a result, it is possible to increase the plasma that is supplied to the substrate Wf.

[0058] Although the number of electrode pairs 51 is three in the above example, the present invention is not limited to this.

[0059] For example, the plasma processing apparatus 1 may be configured to include two pairs of electrodes. In this case, high-frequency powers with phases shifted by 180° are supplied to each electrode. Specifically, a first high-frequency power is supplied to one electrode of a first electrode pair, and a third high-frequency power whose phase is shifted by 180° from the first high-frequency power is supplied to the other electrode of the first electrode pair. A second high-frequency power whose phase is shifted by 180° from the first high-frequency power is supplied to one electrode of a second electrode pair, and a fourth high-frequency power whose phase is shifted by 180° from the second high-frequency power is supplied to the other electrode of the second electrode pair.

[0060] Furthermore, in a configuration including two electrode pairs, high-frequency powers may be supplied to the four electrodes with phases shifted by 90°. That is, a first high-frequency power is supplied to one electrode of a first electrode pair, and a third high-frequency power whose phase is shifted by 180° from the first high-frequency power is supplied to the other electrode of the first electrode pair. A second high-frequency power whose phase is shifted by 90° from the first high-frequency power is supplied to one electrode of a second electrode pair, and a fourth high-frequency power whose phase is shifted by 180° from the second high-frequency power (270° from the first high-frequency power) is supplied to the other electrode of the second electrode pair.

[0061] The plasma processing apparatus 1 may also be configured to include n sets of electrode pairs (n is an integer of 2 or greater). In this case, high-frequency power is supplied to one electrode of each of the n sets of electrode pairs, with the phases shifted by 360° / n. Furthermore, high-frequency power is supplied to the other electrode of each of the n sets of electrode pairs, with the phase shifted by 180° from that of the corresponding electrode. Increasing the number of electrode pairs further improves the circumferential uniformity of the plasma P formed in the plasma generation space 22.

[0062] 7 to 9A and 9B, the plasma processing apparatus 1B (see FIG. 5) according to the third embodiment has been described with reference to a configuration in which high-frequency power with an inverted phase is supplied to the electrode pair 51, but the present invention is not limited to this. The plasma processing apparatus 1 (see FIG. 1) according to the first embodiment may also be configured to supply high-frequency power with an inverted phase to the electrode pair 51. The plasma processing apparatus 1A (see FIG. 4) according to the second embodiment may also be configured to supply high-frequency power with an inverted phase to the electrode pair 51.

[0063] [Electrode Arrangement] Next, an example of the arrangement of the electrodes 51a to 51f provided on the side wall 24 will be described with reference to Figures 10 and 11. Figure 10 is an example of a schematic view of the electrodes 51a to 51f as viewed from above the plasma processing apparatus 1. Figure 11 is an example of a schematic view showing the arrangement of the electrodes 51a to 51f by developing the cylindrical surface of the side wall 24.

[0064] 11 shows the arrangement of electrodes 51a to 51f as viewed from the outside of the cylindrical surface, with the cylindrical surface of side wall 24 expanded from the position indicated by symbol a in Fig. 10 in the circumferential direction L to the position indicated by symbol b. In Fig. 11, the rightward direction corresponds to the circumferential direction L shown in Fig. 10. In Fig. 11, the upward direction corresponds to the vertical direction Z.

[0065] As shown in FIG. 11(a), the longitudinal direction of the electrodes 51a to 51f may be arranged parallel to the circumferential direction L, and the electrodes 51a to 51f may be arranged at the same height.

[0066] 11(b), the longitudinal direction of the electrodes 51a to 51f may be arranged parallel to the circumferential direction L, and adjacent electrodes 51a to 51f may be arranged alternately above and below each other. That is, the electrodes 51a, 51c, and 51e may be arranged in the lower row, and the electrodes 51b, 51d, and 51f may be arranged in the upper row.

[0067] 11(c), the longitudinal direction of the electrodes 51a to 51f may be arranged parallel to the circumferential direction L, adjacent electrodes 51a to 51f may be arranged alternately above and below, and adjacent electrodes may partially overlap each other in the circumferential direction L. This improves the uniformity of the plasma P in the circumferential direction.

[0068] 11(d), the longitudinal direction of the electrodes 51a to 51f may be arranged obliquely with respect to the circumferential direction L, the centers of the electrodes 51a to 51f may be arranged at the same height, and one electrode may partially overlap the other electrode in the circumferential direction L. This improves the uniformity of the plasma P in the circumferential direction.

[0069] The distances D1 to D4 between the adjacent electrodes are preferably set to an appropriate insulation distance (creepage distance) to prevent abnormal discharge and power consumption between the electrodes. Specifically, the distances D1 to D4 between the electrodes are preferably set to 3 mm or more.

[0070] Fig. 12 is an example of a horizontal cross-sectional view showing the structure of the side wall 24 and the electrodes 51a, 51f. In Fig. 11, the circumferential direction L corresponds to the circumferential direction L shown in Fig. 10. The radial direction R is the direction from the center of the cylindrical side wall 24 toward the outside.

[0071] 12, a shielding structure 24a may be provided between the electrodes 51a and 51f. That is, the shielding structure 24a is formed as a protrusion that protrudes from the surface of the electrode 51a and the surface of the electrode 51f toward the center of the side wall 24. This increases the insulation distance (creepage distance) D5 between the adjacent electrodes 51a and 51f, thereby preventing abnormal discharge and the like.

[0072] The above describes a plasma processing apparatus that supplies radicals to a substrate. However, the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims.

[0073] This application claims priority based on Japanese Patent Application No. 2023-223267, filed on December 28, 2023, the entire contents of which are incorporated herein by reference.

[0074] Wf: substrate P: plasma 1: plasma processing apparatus 2: processing vessel 21: processing space 22: plasma generation space 23: intermediate wall 24: side wall 24a: shielding structure 25: insulating member 29: exhaust port 3: mounting table 4: gas supply unit 40, 45: gas supply source 41: shower head (ceiling wall) 42: lower shower head (bottom wall) 46: tube (ion trap member) 47: outlet hole 48: opening 51: electrode pair 51a to 51f: electrodes 60: high frequency supply unit 71: impedance control circuit (first impedance control circuit) 72: impedance control circuit (third impedance control circuit) 73: impedance control circuit (second impedance control circuit) 80: exhaust device

Claims

1. A plasma processing apparatus comprising: a processing container; a mounting table provided in the processing container; a top wall and side walls that define a plasma formation space in the processing container; and a plurality of electrode pairs provided on the side walls to which high-frequency power is supplied.

2. The plasma processing apparatus according to claim 1, wherein the side walls are made of an insulator, the top wall is made of a conductor, and the top wall is grounded via a first impedance control circuit.

3. The plasma processing apparatus according to claim 2, further comprising a bottom wall that defines the plasma formation space, wherein the bottom wall is made of a conductor and is grounded via a second impedance control circuit.

4. The plasma processing apparatus according to claim 1, wherein the side walls are made of an insulator and the top wall is made of an insulator.

5. The plasma processing apparatus according to claim 4, further comprising a bottom wall that defines the plasma formation space, wherein the bottom wall is made of an insulator.

6. The plasma processing apparatus according to claim 3 or claim 5, comprising an ion trap member grounded between the bottom wall and the mounting table.

7. The plasma processing apparatus according to claim 6, wherein the top wall is a shower head that supplies a first gas to the plasma formation space, and the ion trap member is a tube that supplies a second gas to a processing space where the mounting table is provided.

8. The plasma processing apparatus according to claim 1, wherein the mounting table is grounded via a third impedance control circuit.

9. The plasma processing apparatus according to claim 1, wherein the mounting table is grounded.

10. The plasma processing apparatus according to claim 1, wherein a line connecting the centers of the electrodes constituting the electrode pair and the processing surface of the substrate placed on the mounting table are parallel.

11. The plasma processing apparatus according to claim 1, wherein the angle formed by a line connecting the centers of the electrodes constituting the electrode pair and the processing surface of the substrate placed on the mounting table is in the range of -22° to +22°.

12. The plasma processing apparatus according to claim 1, wherein among the electrode pairs, one electrode is supplied with high-frequency power and the other electrode facing the one electrode is grounded.

13. The plasma processing apparatus according to claim 1, wherein among the electrode pairs, one electrode is supplied with high-frequency power and the other electrode facing the one electrode is supplied with high-frequency power having a reversed phase.

14. The plasma processing apparatus according to claim 12 or claim 13, wherein one of the electrodes of the plurality of electrode pairs is supplied with high-frequency power having different phases.

15. The plasma processing apparatus according to claim 12 or claim 13, wherein one of the electrodes of the plurality of electrode pairs is out of phase with each other by 360° / n, where n is an integer of 2 or more, which is the number of the electrode pairs.

16. The plasma processing apparatus according to claim 1, wherein the plurality of electrodes constituting the plurality of electrode pairs are arranged at the same height.

17. The plasma processing apparatus according to claim 1, wherein the plurality of electrodes constituting the plurality of electrode pairs are arranged alternately up and down between adjacent electrodes.

18. The plasma processing apparatus according to claim 17, wherein one of the electrodes and the other electrode adjacent to each other in the circumferential direction of the side wall partially overlap.

19. The plasma processing apparatus according to claim 1, wherein the longitudinal directions of the plurality of electrodes constituting the plurality of electrode pairs are arranged obliquely with respect to the circumferential direction of the side wall, and one of the electrodes and the other electrode adjacent to each other in the circumferential direction of the side wall partially overlap.

20. The plasma processing apparatus according to any one of claims 16 to 19, wherein the side wall has a protruding portion protruding from the surface of the electrode toward the center of the side wall between adjacent electrodes.

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