Plasma processing apparatus

Abstract

To provide a plasma processing apparatus that supplies radicals to a substrate.SOLUTION: A plasma processing apparatus comprises a processing container, a loading platform in the processing container, top and side walls dividing a plasma forming space in the processing container, and a plurality of electrode pairs provided on the side walls and supplied with high-frequency power.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a film forming apparatus including an ion trap member for trapping ions contained in a plasma-processed gas formed in a plasma formation space, and supplying a high density of radicals to a substrate from the plasma-processed gas.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On one aspect, the present disclosure provides a plasma processing apparatus that supplies radicals to a substrate.

Means for Solving the Problems

[0005] To solve the above problems, according to one aspect, there is provided a plasma processing apparatus including a processing container, a mounting table provided in the processing container, a top wall and side walls partitioning 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.

Effects of the Invention

[0006] According to one aspect, it is possible to provide a plasma processing apparatus that supplies radicals to a substrate.

Brief Description of the Drawings

[0007]

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[0008] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions may be omitted.

[0009] [Plasma Processing Apparatus 1 According to the First Embodiment] The plasma processing apparatus 1 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is an example of a longitudinal sectional view of the plasma processing apparatus 1 according to the first embodiment. The plasma processing apparatus 1 generates plasma P of a processing gas and supplies radicals from the processed gas in plasma form to a substrate Wf such as a semiconductor wafer, and is a substrate processing apparatus that performs a desired process (for example, a film forming 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 raw material with a reaction gas that is a processed gas in plasma form to form a film on the substrate Wf by PEALD (Plasma Enhanced Atomic Layer Deposition). Note that the plasma processing apparatus 1 is not limited to this, and may be configured as an apparatus that forms a film on the substrate Wf by PECVD (Plasma Enhanced Chemical Vapor Deposition). Further, the plasma processing apparatus 1 may be an etching apparatus.

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

[0011] The processing container 2 is a substantially cylindrical container made of metal and grounded. The processing container 2 has, inside thereof, a processing space 21 and a plasma formation space 22. The processing space 21 is a space in which a mounting table 3 for supporting the substrate Wf is disposed. The plasma formation space 22 is a space for forming the plasma P of a processing gas, which will be described later. Further, the processing space 21 and the plasma formation space 22 communicate with each other. The processing container 2 has an intermediate wall 23 and a side wall 24 inside thereof. The intermediate wall 23 has an annular shape with a central opening, and partitions the inside of the processing container 2 into an upper space and a lower space. The lower space inside the processing container 2 partitioned by the intermediate wall 23 becomes the processing space 21. Further, the intermediate wall 23 is made of metal and is grounded. On the intermediate wall 23, a side wall 24 composed of a cylindrical insulator is disposed. On the side wall 24, a shower head 41, which will be described later, is disposed. The upper space inside the processing container 2 partitioned by the intermediate wall 23 and partitioned by the side wall 24 and the shower head 41 becomes the plasma formation space 22. That is, the side wall 24 partitions the plasma formation space 22 inside the processing container 2 as the side wall of the plasma formation space 22. Further, the shower head 41 partitions the plasma formation space 22 inside the processing container 2 as the top wall of the plasma formation space 22. The space between the shower head 41 and the side wall 24 is sealed with a seal member 91. The space between the intermediate wall 23 and the side wall 24 is sealed with a seal member 93.

[0012] Further, an exhaust port 29 to which an exhaust device 80 is connected is provided in the bottom wall of the processing container 2 on the processing space 21 side. By the exhaust device 80, the processing space 21 and the plasma formation space 22 are depressurized to a predetermined pressure.

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

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

[0015] A plurality of electrode pairs 51 are provided on the side wall 24 of the plasma formation space 22. Note that the space between the side wall 24 and the electrode pair 51 is sealed with a seal member 92. High-frequency power for generating plasma P is supplied from a high-frequency supply unit 60 to the electrode pair 51. Thereby, capacitively coupled plasma is generated in the plasma formation space 22. In the example shown in FIG. 1, one set of electrode pair 51 is constituted by electrodes 51a and 51d. Further, a plurality of sets of electrode pairs 51 are provided in the circumferential direction of the side wall 24 (see FIG. 2 described later). Here, the electrode pair 51 faces in a direction orthogonal to the normal direction (in other words, the vertical direction) of the substrate mounting surface of the mounting table 3 (in other words, the horizontal direction). In other words, among one set of electrode pairs 51, a line connecting the center of one electrode 51a to the center of the other electrode 51d is parallel (or substantially parallel) to the processing surface (upper surface) of the substrate Wf mounted on the mounting table 3. Here, the line connecting the centers of the electrodes 51a and 51d and the processing surface of the substrate Wf are substantially parallel, and the angle formed therebetween is preferably in the range of -22° to +22°. Further, high-frequency power for generating plasma P is supplied from a high-frequency supply unit 60 to the electrode pair 51.

[0016] FIG. 2 is a schematic view of the electrode pair 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, a configuration including three sets of electrode pairs 51 will be described as an example.

[0017] A plurality of electrodes 51a to 51f are provided on the side wall 24. The plurality of electrodes 51a to 51f are arranged at equal intervals in the circumferential direction of the side wall 24. Further, the plurality of electrodes 51a to 51f are arranged so as to surround the substrate Wf placed on the mounting table 3. The electrode 51a and the electrode 51d are arranged to face each other in the horizontal direction, and a pair of electrodes 51 is constituted. Also, the electrode 51b and the electrode 51e are arranged to face each other in the horizontal direction, and a pair of electrodes 51 is constituted. The electrode 51c and the electrode 51f are arranged to face each other in the horizontal direction, and a pair of electrodes 51 is constituted. In the following description, the electrode 51a is referred to as the U phase, the electrode 51d facing the electrode 51a is referred to as the U' phase, the electrode 51c is referred to as the V phase, the electrode 51f facing the electrode 51c is referred to as the V' phase, the electrode 51e is referred to as the W phase, and the electrode 51b facing the electrode 51e is referred to as the W' phase.

[0018] In addition, in FIG. 2, the electrodes 51a to 51f are shown in an arc shape, but the shapes of the electrodes 51a to 51f are not limited to this. The electrodes 51a to 51f may be formed in a flat plate shape.

[0019] As shown in FIGS. 1 and 2, among the electrode pairs 51, high-frequency power for generating the plasma P is supplied from the high-frequency supply unit 60 to one of the electrodes 51a, 51c, 51e. Also, among the electrode pairs 51, the other electrodes 51b, 51d, 51f are grounded.

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

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

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

[0023] FIG. 3 is an example of the high-frequency power applied to the electrodes 51a, 51c, 51e. High-frequency power with phases shifted by 120° each is supplied to the electrodes 51a, 51c, 51e. Specifically, the 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. The second high-frequency power (V-phase) with a phase shifted by 120° from 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. The third high-frequency power (W-phase) with a phase shifted by 240° from 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 the plurality of electrodes 51a to 51f at equal intervals in the circumferential direction of the side wall 24 and supplying high-frequency power with phases shifted by 120° each, the uniformity in the circumferential direction of the plasma P formed in the plasma formation space 22 is improved.

[0025] Note that the case where the number of electrode pairs 51 is three sets has been described as an example, but it is not limited thereto.

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

[0027] Also, the plasma processing apparatus 1 may be configured to include n pairs (n is an integer of 2 or more) of electrode pairs. In this case, high-frequency power with a phase shift of 360° / n is supplied to one electrode of each of the n pairs of electrodes. Also, the other electrode of each of the n pairs of electrodes is grounded. By increasing the number of pairs of electrodes, the uniformity in the circumferential direction of the plasma P formed in the plasma formation space 22 is further improved.

[0028] Also, in n pairs (n is an integer of 3 or more) of electrode pairs, it is preferable that the one electrode to which the high-frequency power is supplied and the other electrode that is grounded are alternately arranged in the circumferential direction of the side wall 24. Thereby, the uniformity in the circumferential direction of the plasma P formed in the plasma formation space 22 is improved.

[0029] Returning to FIG. 1, the shower head 41 is grounded via an impedance control circuit (first impedance control circuit) 71. The impedance control circuit 71 has, for example, a variable capacitor, an inductor, etc., and controls the impedance so that the shower head 41 has a high impedance with respect to the frequency of the high-frequency power applied to the electrodes 51a, 51c, 51e. Thereby, in the high-frequency power applied to the electrodes 51a, 51c, 51e, the shower head 41 is electrically floating with respect to the electrodes 51b, 51d, 51f that are at the ground potential. This prevents the shower head 41, which is the ceiling wall of the plasma formation space 22, from being regarded as the ground potential. That is, the electrode pairs 51 facing each other can be constituted by the electrodes 51a to 51f provided on the side wall 24.

[0030] Further, the mounting table 3 is grounded via an impedance control circuit (third impedance control circuit) 72. The impedance control circuit 72 has, 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 51a, 51c, 51e. Thereby, in the high-frequency power applied to the electrodes 51a, 51c, 51e, the mounting table 3 is electrically floating with respect to the electrodes 51b, 51d, 51f which are at the ground potential. This prevents ions in the plasma P generated in the plasma formation space 22 from being drawn in by the potential of the mounting table 3. That is, it prevents ions in the plasma P from being drawn into the substrate Wf.

[0031] Here, the plasma processing apparatus according to the reference example will be described. The plasma processing apparatus according to the reference example forms CCP plasma by supplying high-frequency power to the upper electrode or the lower electrode, with a lower electrode provided on the mounting table 3 and an upper electrode (shower head 41) facing the lower electrode in the vertical direction as an electrode pair. In the plasma processing apparatus according to the reference example, ions that move in the vertical direction are generated. For this reason, when the substrate Wf is exposed to the plasma, there is a risk that ions will be incident on the substrate Wf and damage the substrate Wf. Also, there is a risk that the characteristics of the semiconductor device formed on the substrate Wf will deteriorate due to ion damage.

[0032] On the other hand, according to the plasma processing apparatus 1 according to the first embodiment, by providing the electrode pair 51 for supplying high-frequency power for plasma generation on the side wall 24 of the plasma formation space 22 and arranging the electrode pair 51 to face each other in the horizontal direction, ions that move in the vertical direction are suppressed. Therefore, ions incident on the substrate Wf are suppressed, and deterioration of the characteristics of the semiconductor device formed on the substrate Wf is suppressed. On the other hand, radicals in the plasma P diffuse from the plasma formation space 22 to the processing space 21 and are supplied to the substrate Wf. Thereby, radicals can be supplied to the substrate Wf and a desired process can be performed on the substrate Wf.

[0033] In addition, in the configuration shown in FIG. 1, the plasma processing apparatus 1 that supplies radicals to the substrate Wf has been described as an example, but the present invention is not limited thereto. In the 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. Thereby, while supplying radicals to the substrate Wf, ions in the plasma P can be drawn into the substrate Wf to supply ions to the substrate Wf.

[0034] [Plasma Processing Apparatus 1A According to the 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 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) has a different structure for partitioning the plasma formation space 22 as compared with the plasma processing apparatus 1 according to the first embodiment (see FIG. 1). Other structures are the same, and redundant descriptions are omitted.

[0035] The processing container 2 has an intermediate wall 23, side walls 24, an insulating member 25, and a lower shower head 42 inside thereof. The intermediate wall 23 has an annular shape with a central opening, and divides the inside of the processing container 2 into an upper space and a lower space. The lower space inside the processing container 2 partitioned by the intermediate wall 23 becomes the processing space 21. Also, the intermediate wall 23 is made of metal and is grounded. A lower shower head 42 is disposed at the opening of the intermediate wall 23 via the insulating member 25. The lower shower head 42 has a plurality of through holes penetrating from the plasma formation space 22 to the processing space 21, and is composed of a conductor such as metal. Also, a side wall 24 composed of a cylindrical insulator is disposed on the insulating member 25. A shower head 41 is disposed on the side wall 24. The space inside the processing container 2 partitioned by the intermediate wall 23 and defined by the side wall 24, the shower head 41, and the lower shower head 42 becomes the plasma formation space 22. That is, the side wall 24 partitions the plasma formation space 22 inside the processing container 2 as the side wall of the plasma formation space 22. Also, the shower head 41 partitions the plasma formation space 22 inside the processing container 2 as the top wall of the plasma formation space 22. Also, the lower shower head 42 partitions the plasma formation space 22 inside the processing container 2 as the bottom wall of the plasma formation space 22. The space between the shower head 41 and the side wall 24 is sealed with a seal member 91. The space between the intermediate wall 23 and the insulating member 25 is sealed with a seal member 93. The space between the insulating member 25 and the side wall 24 is sealed with a seal member 94.

[0036] Further, the lower showerhead 42 is grounded via an impedance control circuit (second impedance control circuit) 73. The impedance control circuit 73 has, for example, a variable capacitor, an inductor, etc., and controls the impedance so that the lower showerhead 42 has a high impedance with respect to the frequency of the high-frequency power applied to the electrodes 51a, 51c, 51e. Thereby, in the high-frequency power applied to the electrode 51a, the lower showerhead 42 is electrically floating with respect to the electrodes 51b, 51d, 51f which are at the ground potential. This prevents the lower showerhead 42, which is the bottom wall of the plasma formation space 22, from being regarded as the ground potential. That is, the electrode pairs 51 can be constituted by the electrodes 51a to 51f provided on the side wall 24.

[0037] As described above, according to the plasma processing apparatus 1A according to the second embodiment, the electrode pairs 51 for supplying high-frequency power for plasma generation are provided on the side wall 24 of the plasma formation space 22, and the electrode pairs 51 are arranged so as to face each other in the horizontal direction, thereby suppressing ions moving in the vertical direction. Therefore, ions incident on the substrate Wf are suppressed, and deterioration of the characteristics of the semiconductor device formed on the substrate Wf is suppressed. On the other hand, radicals in the plasma P diffuse from the plasma formation space 22 to the processing space 21 and are supplied to the substrate Wf. Thereby, radicals can be supplied to the substrate Wf, and a desired process can be performed on the substrate Wf.

[0038] [Plasma Processing Apparatus 1B According to the 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 longitudinal 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) has a different structure for supplying the film-forming gas as compared with the plasma processing apparatus 1A according to the second embodiment (see FIG. 4). Other structures are the same, and redundant descriptions are omitted.

[0039] A plurality of tubular bodies 46 are arranged in the opening portion of the intermediate wall 23. The tubular body 46 is made of a conductor such as metal and is grounded together with the intermediate wall 23. A film-forming gas is supplied from the gas supply source 45 to the tubular body 46, and the film-forming gas is supplied from the discharge hole 47 to the processing space 21. Further, there is an opening 48 between the tubular bodies 46, which communicates the plasma formation space 22 and the processing space 21.

[0040] Here, a case where a film-forming process is performed on the substrate Wf by PEALD will be described as an example.

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

[0042] Next, the control unit controls the gas supply source 40 to supply a reaction gas (first gas) from the shower head 41 to the plasma formation space 22. Further, the control unit controls the high-frequency supply unit 60 to supply high-frequency power to the electrode pair 51. Thereby, plasma P of the reaction gas is generated in the plasma formation space 22 (second step). Here, the plasma P contains radicals and ions. The radicals diffuse from the plasma formation space 22 through the through holes and the opening 48 of the lower shower head 42 into the processing space 21. Thereby, radicals of the reaction gas are supplied to the substrate Wf. A film is formed on the surface of the substrate Wf by the reaction between the film-forming gas adsorbed on the surface of the substrate Wf and the radicals of the reaction gas. Then, taking the step of supplying the film-forming gas and the step of generating the plasma P of the reaction gas as one cycle, and repeating this cycle a predetermined number of times, a film with a desired film thickness is formed on the substrate Wf.

[0043] On one hand, the ions of the plasma P are suppressed from moving in the vertical direction by arranging the electrode pair 51 to which high-frequency power is supplied so as to face each other in the horizontal direction. That is, the number of ions passing through the through-holes of the lower shower head 42 is suppressed. Further, a pipe body 46 having a ground potential is disposed below the lower shower head 42. The ions that have passed through the through-holes of the lower shower head 42 are drawn into the pipe body 46 having a ground potential. That is, the ions that have passed through the through-holes of the lower shower head 42 are trapped by the pipe body 46. In this way, the pipe body 46 functions as an ion trap member. Thereby, the ions of the reaction gas supplied to the substrate W can be further reduced. Therefore, the pipe body 46 is, in other words, an ion trap plate capable of supplying gas in a shower shape.

[0044] As described above, according to 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 side wall 24 of the plasma formation space 22, and the electrode pair 51 is arranged so as to face each other in the horizontal direction, thereby suppressing the ions moving in the vertical direction. Therefore, the ions incident on the substrate Wf are suppressed, and the deterioration of the characteristics of the semiconductor device formed on the substrate Wf is suppressed. On the other hand, the radicals in the plasma P diffuse from the plasma formation space 22 to the processing space 21 and are supplied to the substrate Wf. Thereby, radicals can be supplied to the substrate Wf, and a desired process can be performed on the substrate Wf.

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

[0046] The shower head 41A and the lower shower head 42A are made of a dielectric (insulator). Also, the shower head 41A and the lower shower head 42A may be configured to be covered with a dielectric (insulator). As a result, the shower head 41A and the lower shower head 42A have a high impedance with respect to the frequency of the high-frequency power applied to the electrodes 51a, 51c, 51e. Thereby, in the high-frequency power applied to the electrodes 51a, 51c, 51e, the shower head 41A and the lower shower head 42A are electrically floating with respect to the electrodes 51b, 51d, 51f that are at the ground potential. This prevents the shower head 41A and the lower shower head 42A, which form the top wall and the bottom wall of the plasma formation space 22, from being regarded as the ground potential. Therefore, the impedance control circuits 71, 73 (see FIG. 4) can be omitted.

[0047] In FIG. 6, in the configuration of the plasma processing apparatus 1A (see FIG. 4) according to the second embodiment, the configuration in which the shower head 41A and the lower shower head 42A are made of a dielectric or covered with a dielectric has been described as an example, but the present invention is not limited thereto. 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 a dielectric or covered with a dielectric. 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 a dielectric or covered with a dielectric.

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

[0049] As shown in FIG. 8, a plurality of electrodes 51a to 51f are provided on the side wall 24. The plurality of electrodes 51a to 51f are arranged at equal intervals in the circumferential direction of the side wall 24. Further, the plurality of electrodes 51a to 51f are arranged so as to surround the substrate Wf placed on the mounting table 3. The electrode 51a and the electrode 51d are arranged to face each other in the horizontal direction, and a set of electrode pair 51 is formed. Also, the electrode 51b and the electrode 51e are arranged to face each other in the horizontal direction, and a set of electrode pair 51 is formed. The electrode 51c and the electrode 51f are arranged to face each other in the horizontal direction, and a set of electrode pair 51 is formed. In the following description, the electrode 51a will be described as the U phase, the electrode 51d facing the electrode 51a as the U' phase, the electrode 51c as the V phase, the electrode 51f facing the electrode 51c as the V' phase, the electrode 51e as the W phase, and the electrode 51b facing the electrode 51e as the W' phase.

[0050] Note that in FIG. 8, the electrodes 51a to 51f are shown in an arc shape, but the shapes of the electrodes 51a to 51f are not limited to this. The electrodes 51a to 51f may be configured to be formed in a flat plate shape.

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

[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 the impedance matcher 622. Also, the high-frequency power supply 623 supplies high-frequency power to the electrode 51d via the impedance matcher 624. Here, the high-frequency power supply 623 supplies high-frequency power with a phase inverted from that of 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. Also, 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 each high-frequency power supply of the RF supply units 62A to 64A to control the phases 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] FIG. 9 is an example of the high-frequency power applied to electrodes 51a to 51f. High-frequency power with phases shifted by 120° each is supplied to electrodes 51a, 51c, 51e (U phase, V phase, W phase). To the electrode 51d (U' phase) facing the electrode 51a, high-frequency power with a phase inverted by 180° from the high-frequency power supplied to the electrode 51a (U phase) is supplied. To the electrode 51f (V' phase) facing the electrode 51c, high-frequency power with a phase inverted by 180° from the high-frequency power supplied to the electrode 51c (V phase) is supplied. To the electrode 51b (W' phase) facing the electrode 51e, high-frequency power with a phase inverted by 180° from the high-frequency power supplied to the electrode 51e (W phase) is supplied.

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

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

[0057] Further, by inverting the phase of the high-frequency power between the electrode pairs 51, the potential difference between the electrode pairs 51 can be increased. Thereby, the intensity of the plasma P can be increased and the generated radicals can be increased. Therefore, the plasma supplied to the substrate Wf can be increased.

[0058] Note that the case where the number of the electrode pairs 51 is three sets has been described as an example, but it is not limited thereto.

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

[0060] Also, in a configuration including two pairs of electrodes, a configuration may be adopted in which high-frequency power with a phase shift of 90° is supplied to the four electrodes. That is, the first high-frequency power is supplied to one electrode of the first pair of electrodes, and the third high-frequency power with a 180° phase shift from the first high-frequency power is supplied to the other electrode of the first pair of electrodes. The second high-frequency power with a 90° phase shift from the first high-frequency power is supplied to one electrode of the second pair of electrodes, and the fourth high-frequency power with a 180° phase shift from the second high-frequency power (with a 270° phase shift from the first high-frequency power) is supplied to the other electrode of the second pair of electrodes.

[0061] Further, the plasma processing apparatus 1 may be configured to include n pairs (n is an integer of 2 or more) of electrodes. In this case, high-frequency power with a phase shift of 360° / n is supplied to one electrode of each of the n pairs of electrodes. Also, high-frequency power with a 180° phase shift from the corresponding one electrode is supplied to the other electrode of each of the n pairs of electrodes. By increasing the number of pairs of electrodes, the uniformity in the circumferential direction of the plasma P formed in the plasma formation space 22 is further improved.

[0062] Note that, in FIGS. 7 to 9, in the configuration of the plasma processing apparatus 1B (see FIG. 5) according to the third embodiment, the configuration in which high-frequency power with an inverted phase is supplied to the electrode pair 51 has been described as an example, but the present invention is not limited thereto. In the configuration of the plasma processing apparatus 1 (see FIG. 1) according to the first embodiment, a configuration in which high-frequency power with an inverted phase is supplied to the electrode pair 51 may be adopted. In the configuration of the plasma processing apparatus 1A (see FIG. 4) according to the second embodiment, a configuration in which high-frequency power with an inverted phase is supplied to the electrode pair 51 may be adopted.

[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 FIGS. 10 and 11. FIG. 10 is an example of a schematic view of the electrodes 51a to 51f as seen from above the plasma processing apparatus 1. FIG. 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] Here, the cylindrical surface of the side wall 24 from the position indicated by reference sign a to the position indicated by reference sign b in the circumferential direction L in FIG. 10 is developed, and the arrangement of the electrodes 51a to 51f as seen from the outside of the cylindrical surface is shown in FIG. 11. In FIG. 11, the right 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 directions 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] As shown in FIG. 11(b), the longitudinal directions of the electrodes 51a to 51f may be arranged parallel to the circumferential direction L, and the adjacent electrodes 51a to 51f may be arranged alternately up and down. That is, the electrodes 51a, 51c, 51e may be arranged in the lower stage, and the electrodes 51b, 51d, 51f may be arranged in the upper stage.

[0067] As shown in Fig. 11(c), the longitudinal directions of the electrodes 51a to 51f may be arranged parallel to the circumferential direction L, and the adjacent electrodes 51a to 51f may be arranged alternately up and down, and one electrode and the other electrode adjacent in the circumferential direction L may partially overlap. Thereby, the uniformity in the circumferential direction of the plasma P is improved.

[0068] As shown in Fig. 11(d), the longitudinal directions 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 and the other electrode may partially overlap in the circumferential direction L. Thereby, the uniformity in the circumferential direction of the plasma P is improved.

[0069] In addition, the distances D1 to D4 between the adjacent electrodes are preferably set to an appropriate insulation distance (creepage distance) in order to prevent abnormal discharge and power consumption between the electrodes. Specifically, the distances D1 to D4 between the electrodes are preferably 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 and 51f. In Fig. 11, the circumferential direction L corresponds to the circumferential direction L shown in Fig. 10. The radial direction R is a direction from the center of the cylindrical side wall 24 toward the outside.

[0071] As shown in Fig. 12, a shielding structure 24a may be provided between the electrodes 51a and 51f. That is, a shielding structure 24a is formed as a protruding portion protruding from the surfaces of the electrodes 51a and 51f toward the center of the side wall 24. Thereby, the insulation distance (creepage distance) D5 between the adjacent electrodes 51a and 51f can be increased. Thereby, abnormal discharge and the like can be prevented.

[0072] As described above, the plasma processing apparatus for supplying radicals to the substrate has been described. However, the present disclosure is not limited to the above-described embodiments and the like, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims.

Explanation of Reference Numerals

[0073] Wf substrate P plasma 1 Plasma processing apparatus 2 Processing container 21 Processing space 22 Plasma formation 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 body (ion trap member) 47 Discharge hole 48 Opening 51 Electrode pair 51a~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 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. A plasma processing apparatus.

2. 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. The plasma processing apparatus according to Claim 1.

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

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

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

6. An ion trap member that is grounded is provided between the bottom wall and the mounting table. The plasma processing apparatus according to any one of Claims 3 or 5.

7. 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 the processing space where the mounting table is provided. The plasma processing apparatus according to Claim 6.

8. The mounting table is grounded via a third impedance control circuit. The plasma processing apparatus according to Claim 1.

9. The mounting table is grounded. The plasma processing apparatus according to Claim 1.

10. 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. The plasma processing apparatus according to Claim 1.

11. 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 within the range of -22° to +22°. The plasma processing apparatus according to Claim 1.

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

13. 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 with an inverted phase. The plasma processing apparatus according to Claim 1.

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

15. 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, with respect to the number of the electrode pairs. The plasma processing apparatus according to claim 12 or claim 13.

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

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

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

19. 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. The plasma processing apparatus according to claim 1.

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

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