Plasma source and plasma processing apparatus

Abstract

To miniaturize a plasma source.SOLUTION: The present invention provides a plasma source having: a housing for defining a plasma generation chamber; a gas introduction port that is provided to the housing, and is for introducing a gas; a supply port that is provided to the housing, and is for supplying an active species of the plasma generated from the gas in the plasma generation chamber; an ignition power supply port that is provided to the housing, and supplies a high-frequency power for igniting the plasma in the plasma generation chamber; and a maintaining power supply port that is provided to the housing, and supplies the high-frequency power for maintaining the plasma ignited in the plasma generation chamber.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to plasma sources and plasma processing apparatus. [Background technology]

[0002] For example, Patent Document 1 proposes a plasma processing apparatus equipped with a remote plasma unit. The remote plasma unit is an inductively coupled plasma source and defines a plasma generation space above the plasma processing apparatus. The remote plasma unit has a coil surrounding the plasma generation space, and a high-frequency power source that supplies high-frequency power is connected to the coil.

[0003] For example, Patent Document 2 provides a helical coil-coupled remote plasma generator using a helical coil of a slow wave structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-49529 A [Patent Document 2] Special Publication No. 2006-516806 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that allows for miniaturization of a plasma source. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a plasma source having a housing defining a plasma generation chamber, a gas inlet provided in the housing for introducing a gas, a supply port provided in the housing for supplying active species of plasma generated from the gas in the plasma generation chamber, an ignition power supply port provided in the housing for supplying high frequency power to ignite plasma in the plasma generation chamber, and a maintenance power supply port provided in the housing for supplying high frequency power to maintain the plasma ignited in the plasma generation chamber. Effect of the Invention

[0007] According to one aspect, the plasma source can be made smaller. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional perspective view showing an example of a plasma processing apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of connection between a plasma source and a microwave power source according to the first embodiment. [Diagram 3] FIG. 2 is a vertical cross-sectional view showing an example of the configuration of a plasma source according to the first embodiment. [Figure 4] 5A and 5B are diagrams showing an example of the relationship between the structural height and the resonant frequency when plasma is ignited and when plasma is maintained; [Diagram 5] FIG. 4 is a diagram showing a modified example of the plasma source according to the first embodiment. [Figure 6] FIG. 11 is a cross-sectional perspective view showing an example of a plasma processing apparatus according to a second embodiment. [Figure 7] FIG. 13 is a view showing a ceiling surface of a plasma processing apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment 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 duplicated descriptions may be omitted.

[0010] First Embodiment [Plasma processing equipment] A plasma processing apparatus 10 having a plasma source (remote plasma source) according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional perspective view showing an example of the plasma processing apparatus 10 according to the first embodiment.

[0011] The plasma processing apparatus 10 shown in FIG. 1 includes a plasma source 2 and a processing chamber 3. The plasma source 2 includes a housing 40. The housing 40 forms a flat hollow space centered on an axis AX. The plasma source 2 and the processing chamber 3 are connected by a connecting part 23. Microwave (high frequency, electromagnetic wave) power and gas are supplied into the housing 40, and plasma is generated from the gas by the electric field of the microwave power. The activated species in the generated plasma are supplied to a plasma processing chamber 30e in the processing chamber 3 via the connecting part 23. The activated species sent from the plasma source 2 to the plasma processing chamber 30e are dissociated again by, for example, high frequency power applied to the processing chamber 3, and used to process the substrate W.

[0012] The plasma source 2, the connecting portion 23, and the processing chamber 3 have an axis AX as a center line. The axis AX is an axis extending in a vertical direction. In this embodiment, the processing chamber 3 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape and is open at the top. The chamber body 12 provides a side wall and a bottom of the processing chamber 3. The chamber body 12 is formed of a metal such as aluminum. The chamber body 12 is grounded.

[0013] The sidewall of the chamber body 12 provides a passage 12p. The substrate W passes through the passage 12p when being transferred between the inside and the outside of the processing chamber 3. The passage 12p can be opened and closed by a gate valve 12v. The gate valve 12v is provided along the sidewall of the chamber body 12.

[0014] The processing chamber 3 further includes a top wall 14. The top wall 14 is made of a metal such as aluminum. The top wall 14 closes an upper opening of the chamber body 12. The top wall 14 and the chamber body 12 are grounded.

[0015] The bottom of the processing chamber 3 provides an exhaust port 16a. The exhaust port 16a is connected to an exhaust system 16. The exhaust system 16 includes a pressure controller including an automatic pressure control valve and a vacuum pump such as a turbomolecular pump.

[0016] The processing chamber 3 further includes a mounting table 18. The mounting table 18 is provided in the processing chamber 3. The mounting table 18 is configured to support a substrate W mounted thereon. The substrate W is mounted on the mounting table 18 in a substantially horizontal state. The mounting table 18 may be supported by a support member 19. The support member 19 extends upward from the bottom of the processing chamber 3. The mounting table 18 and the support member 19 may be formed from a dielectric material such as aluminum nitride.

[0017] The processing chamber 3 further includes a showerhead 20. The showerhead 20 is made of a metal such as aluminum. The showerhead 20 has a substantially disk shape and a hollow structure. The showerhead 20 shares an axis AX as its center line. The showerhead 20 is provided above the mounting table 18 and below the ceiling wall 14.

[0018] The showerhead 20 provides a diffusion chamber 30d therein. The showerhead 20 has a plurality of gas holes 20i penetrating downward from the diffusion chamber 30d in the thickness direction of the showerhead 20. The plurality of gas holes 20i open to the lower surface of the showerhead 20.

[0019] The mounting table 18 is provided below the shower head 20 and faces the shower head 20. Gas is introduced from the diffusion chamber 30d through a plurality of gas holes 20i into a plasma processing chamber 30e between the shower head 20 and the mounting table 18. The mounting table 18 also functions as a lower electrode, and the shower head 20 also functions as an upper electrode.

[0020] The periphery of the showerhead 20 is covered with a dielectric member 33 such as aluminum oxide. The periphery of the mounting table 18 is covered with a dielectric member 34 such as aluminum oxide. If high-frequency power is not applied to the showerhead 20, the dielectric member 33 does not need to be disposed. However, it is preferable to dispose the dielectric member 33 in order to determine the area of ​​the showerhead 20 that functions as a counter electrode for the mounting table 18. It is also preferable to dispose the dielectric member 33 in order to equalize the ratio of anodes and cathodes of the electrodes.

[0021] A high frequency power supply 52 is connected to the mounting table 18 via a matching device 53. The matching device 53 has an impedance matching circuit. The impedance matching circuit is configured to match the impedance on the load (plasma) side to the output impedance of the high frequency power supply 52. ​​The frequency of the high frequency power supplied from the high frequency power supply 52 is lower than the frequencies of the VHF waves and microwaves supplied to the plasma source 2, and is a frequency of 60 MHz or less. The frequency of the high frequency power may be 13.56 MHz. The high frequency power supply 52 may be connected to the shower head 20 to supply high frequency power to the shower head 20.

[0022] (Plasma source) The plasma source 2 is disposed on a ceiling wall 14 of the processing chamber 3. Fig. 2 is a diagram showing an example of a connection between the plasma source 2 and a microwave power supply 48 according to the first embodiment.

[0023] 1 and 2, the plasma source 2 has a housing 40. The housing 40 has a gas inlet 40a, a supply port 40b, ignition power supply ports 45a and 45b, and maintenance power supply ports 46a and 46b.

[0024] 3 is an enlarged cross-sectional view of the upper half of the plasma source 2 according to the first embodiment. As shown in FIG. 3, the housing 40 forms a hollow rectangular space, and defines a plasma generation chamber U therein. The housing 40 has a gas inlet 40a on the upper surface and a supply port 40b on the lower surface. A gas nozzle 51 penetrates the gas inlet 40a, and its tip is inserted into the housing 40. The gas nozzle 51 is connected to a gas supply source 50, and supplies gas supplied from the gas supply source 50 into the housing 40.

[0025] The plasma source 2 is connected to the ceiling wall 14 of the processing chamber 3 via a connecting part 23. The connecting part 23 shares an axis AX as its center line. The connecting part 23 is made of a metal such as aluminum, and is a cylindrical annular member.

[0026] The upper end of the connecting part 23 is connected to the housing 40 at the lower surface of the housing 40 and communicates with the supply port 40b. The lower end of the connecting part 23 is fixed to the ceiling wall 14 so as to communicate with a through hole 14a provided in the center of the upper surface of the ceiling wall 14 of the processing chamber 3. The supply port 40b is an opening provided in the housing 40 for supplying active species of plasma generated in the plasma generation chamber U to the downstream side, i.e., the plasma processing chamber 30e side. The active species in the plasma generated in the plasma generation chamber U in the plasma source 2 is supplied to the plasma processing chamber 30e of the processing chamber 3 through the connecting part 23 and the through hole 14a.

[0027] The housing 40 is made of a metal such as aluminum and has a ground potential. As shown in Figures 1 and 2, the plasma source 2 has ignition power supply ports 45a and 45b on a side surface 40c of the housing 40 that has a larger area, and has maintenance power supply ports 46a and 46b on a side surface 40d opposite to the side surface 40c.

[0028] The ignition power supply ports 45a, 45b are provided vertically on the side surface 40c of the housing 40. The first resonators 41a, 41b are attached to the ignition power supply ports 45a, 45b, respectively. The first resonators 41a, 41b are configured to adjust the structural height of the first resonators 41a, 41b, which will be described later, so that the frequency of the microwave power becomes an appropriate frequency (resonance frequency) for igniting plasma. This allows microwave power for igniting plasma to be supplied from the ignition power supply ports 45a, 45b to the plasma generation chamber U.

[0029] The maintenance power supply ports 46a, 46b are provided vertically on the side surface 40d of the housing 40, one above the other. The second resonators 42a, 42b are attached to the maintenance power supply ports 46a, 46b, respectively. The second resonators 42a, 42b are configured to adjust the structural height of the second resonators 42a, 42b, which will be described later, so that the frequency of the microwave power becomes an appropriate frequency (resonant frequency) for maintaining the plasma after ignition. This allows microwave power for maintaining the plasma to be supplied from the maintenance power supply ports 46a, 46b to the plasma generation chamber U.

[0030] In the housing 40, the gas flows from the upstream side to the downstream side, with the gas inlet 40a being the upstream side and the supply port 40b being the downstream side. Therefore, ignition power supply ports 45a, 45b and maintenance power supply ports 46a, 46b are provided on a path V connecting the gas inlet 40a and the supply port 40b. The ignition power supply ports 45a, 45b are also collectively referred to as ignition power supply ports 45. The maintenance power supply ports 46a, 46b are also collectively referred to as maintenance power supply ports 46. The first resonators 41a, 41b are also collectively referred to as first resonators 41. The second resonators 42a, 42b are also collectively referred to as second resonators 42.

[0031] The number of ignition power supply ports 45 and first resonators 41 must be equal to the number required to ignite plasma, whereas the number of maintenance power supply ports 46 and second resonators 42 must be equal to the number required to maintain plasma. For this reason, there may be a difference between the number of ignition power supply ports 45 and first resonators 41 and the number of maintenance power supply ports 46 and second resonators 42.

[0032] The first resonators 41a and 41b are attached to the ignition power supply ports 45a and 45b, respectively. In this embodiment, the ignition power supply ports 45a and 45b and the first resonators 41a and 41b are multiple, but this is not limited thereto. The ignition power supply port 45 and the first resonator 41 may be one or two or more as long as they can ignite plasma from the gas supplied to the plasma generation chamber U and generate initial plasma. However, since the first resonator 41 is used for a short time at the time of plasma ignition, it is sufficient that one is provided on the path V as long as it can ignite plasma. In other words, the number of first resonators 41 for plasma ignition is as small as possible because they are used instantaneously at the time of plasma ignition.

[0033] The second resonators 42a and 42b are attached to the maintenance power supply ports 46a and 46b, respectively. In this embodiment, the maintenance power supply ports 46a and 46b and the second resonators 42a and 42b are multiple, but this is not limited thereto. The maintenance power supply port 46 and the second resonator 42 may be one or two or more as long as the plasma ignited in the plasma generation chamber U can be maintained. However, since the second resonator 42 is used to maintain the plasma, a plurality of resonators may be provided on the path V. When the ignited plasma cannot reach the supply port 40b with one resonator, the number of the second resonators 42 for maintaining the plasma may be two or more on the path V connecting the gas inlet 40a and the supply port 40b. In other words, the maintenance power supply ports 46 and the second resonators 42 for maintaining the plasma are provided in sufficient numbers to supply the power required for plasma processing.

[0034] In this embodiment, the ignition power supply port 45 and the maintenance power supply port 46 are provided at opposing positions on the side surfaces 40c and 40d of the housing 40. The ignition power supply port 45a and the maintenance power supply port 46a are provided at opposing positions, and the ignition power supply port 45b and the maintenance power supply port 46b are provided at opposing positions. This allows the plasma generated in the vicinity of the ignition power supply port 45 by the high frequency power supplied from the ignition power supply port 45 using the first resonator 41 to be efficiently maintained by the high frequency power supplied from the maintenance power supply port 46 using the second resonator 42.

[0035] However, the ignition power supply port 45 and the maintenance power supply port 46 do not necessarily have to be provided in opposing positions. For example, one ignition power supply port 45 may be provided on the side surface 40c of the housing 40, and multiple maintenance power supply ports 46 may be provided on the side surface 40d.

[0036] The first resonator 41 and the second resonator 42 have a comb-tooth shape and have the same basic structure. The first resonator 41 adjusts the structural height (see X1 in FIG. 3) of the first resonator 41 so that the frequency of the microwave power becomes an appropriate frequency (resonant frequency) for igniting plasma. The second resonator 42 adjusts the structural height (see X2 in FIG. 3) of the second resonator 42 described later so that the frequency of the microwave power becomes an appropriate frequency (resonant frequency) for maintaining plasma. As described later, the structural height X1 adjusted by the first resonator 41 is different from the structural height X2 adjusted by the second resonator 42. The first resonator 41a, the second resonator 42a, and their surrounding structures shown in FIG. 3 will be described below. The first resonator 41a and the second resonator 42a are comb-tooth resonators having comb-tooth fins. The first resonator 41a and the second resonator 42a shown in FIG. 3 have the same dimensions such as the width and length of the comb teeth.

[0037] The structure of the first resonator 41a and its vicinity will be described. In the housing 40, a disk-shaped quartz member 60, a disk-shaped slot antenna 61, and a disk-shaped dielectric 62 are provided in this order adjacent to the inner surface on the side 40c side. The quartz member 60, the slot antenna 61, and the dielectric 62 share a common central axis. The quartz member 60 is disposed in a recess formed on the inner surface of the housing 40. The dielectric 62 is formed of, for example, alumina or aluminum nitride, and faces the plasma generation chamber U. The slot antenna 61 is held between the quartz member 60 and the dielectric 62. The diameter of the quartz member 60 is smaller than the diameters of the slot antenna 61 and the dielectric 62. The diameters of the slot antenna 61 and the dielectric 62 are the same.

[0038] A conductive power supply portion 60a is embedded in a through hole in the center of the quartz member 60. The slot antenna 61 is a thin metal plate provided between the quartz member 60 and the dielectric material 62, and has a ring-shaped slot 61a (space).

[0039] The waveguide 83 has a coaxial structure including an outer conductor 83a and an inner conductor 83b, and the space between the outer conductor 83a and the inner conductor 83b is filled with a dielectric material such as PTFE (Poly Tetra Fluoro Ethylene). The waveguide 83 is connected to a cable 79. The cable 79 is connected to a microwave power source 48, and guides microwaves output from the microwave power source 48 to the first resonator 41a via the waveguide 83 (see FIG. 2).

[0040] The housing 41a1 of the first resonator 41a has a cylindrical side portion 69a1 and an end portion 69a2. The cylindrical side portion 69a1 and the end portion 69a2 are formed of a metal such as aluminum. A part of the outer conductor 83a is the housing 41a1 of the first resonator 41a, and the housing 41a1 is at ground potential together with the grounded processing chamber 3. In addition, a portion 69a3 of the housing 41a1 other than the movable range of the ground fin 65 is filled with a dielectric material such as PTFE (polytetrafluoroethylene).

[0041] The outer conductor 83a is cylindrical, and an input port P1 is formed on a side surface 69a1 of the first resonator 41a. An ignition power supply port 45a that functions as an output port is formed on the end of the outer conductor 83a near the input port P1, and the other end 69a2 is formed in a disk shape to close the cylinder. A rod-shaped portion 64 for moving the ground fin 65 in the left-right direction in FIG. 3 penetrates the center of the end 69a2.

[0042] A ground fin 65 is provided inside the housing 41a1. The ground fin 65 has a plurality of fins 66 and a rod-shaped portion 64. The plurality of fins 66 and the rod-shaped portion 64 are formed of a conductor such as aluminum. The plurality of fins 66 have, for example, a concentric columnar and cylindrical shape. The first resonator 41a is a comb-shaped resonator in which the plurality of fins 66 have a comb-shaped cross section shown in FIG. 3.

[0043] A plurality of fins 67 are provided inside the housing 41a1. The plurality of fins 67 are a triple cylindrical multipole antenna. The plurality of fins 67 are comb-shaped in the cross section shown in FIG.

[0044] The sides of the multiple fins 67 are fixed to a cylindrical base 63. The fins 67 and the base 63 are made of a conductor such as aluminum. The ground fins 65 are slidable, and even when the ground fins 65 are inserted deepest toward the fins 67, they do not come into contact with the fins 67. By sliding the ground fins 65, the insertion amount of the fins 66 into the fins 67 is changed. By changing the insertion amount of the ground fins 65 (fins 66) in this way to change the size of the resonance space, the resonance frequency of the microwave power passing through the first resonator 41a can be controlled to be an appropriate resonance frequency for igniting plasma.

[0045] 3, the gap from the tips of the fins 66 to the surface of the base 63 to which the fins 67 are fixed is defined as X1. The gap from the tips of the fins 67 to the surface of the ground fin 65 to which the fins 66 are fixed may also be defined as X1.

[0046] An alumina ring member 54a is disposed near the ignition power supply port 45a, which is fitted into a hollowed-out portion of the housing 40. The ring member 54a is adjacent to a conductor power supply portion 60a. The ring member 54a functions as the ignition power supply port 45a. Microwave power passes through the connection portion 63a, the first resonator 41a, the power supply portion 60a, the slot antenna 61 (slot 61a), and the dielectric 62 to be supplied into the housing 40.

[0047] As a result, the gas introduced from the gas inlet 40a is decomposed by the energy of the microwaves, and plasma is ignited in the plasma generation chamber U, generating an initial plasma. By arranging the ignition power supply port 45a and the first resonator 41a on the path V connecting the gas inlet 40a and the supply port 40b, plasma can be ignited efficiently in the plasma generation chamber U.

[0048] Next, the structure of the second resonator 42a and its vicinity will be described. In the housing 40, a disk-shaped quartz member 70, a disk-shaped slot antenna 71, and a disk-shaped dielectric 72 are provided in this order adjacent to the inner surface of the side 40d side. The quartz member 70, the slot antenna 71, and the dielectric 72 share a common central axis. The quartz member 70 is disposed in a recess formed in the inner surface of the housing 40. The dielectric 72 is formed of, for example, alumina or aluminum nitride, and faces the plasma generation chamber U. The slot antenna 71 is held between the quartz member 70 and the dielectric 72. The diameter of the quartz member 70 is smaller than the diameters of the slot antenna 71 and the dielectric 72. The diameters of the slot antenna 71 and the dielectric 72 are the same.

[0049] A conductor power supply portion 70a is embedded in a through hole in the center of the quartz member 70. The slot antenna 71 is a thin metal plate provided between the quartz member 70 and a dielectric material 72, and has a ring-shaped slot 71a (space).

[0050] The waveguide 84 has a coaxial structure including an outer conductor 84a and an inner conductor 84b, and the space between the outer conductor 84a and the inner conductor 84b is filled with a dielectric material such as PTFE. The waveguide 84 is connected to a cable 89. The cable 89 is connected to the microwave power source 48, and guides the microwaves output from the microwave power source 48 to the second resonator 42a (see FIG. 2).

[0051] The housing 42a1 of the second resonator 42a has a cylindrical side portion 69b1 and an end portion 69b2. The cylindrical side portion 69b1 and the end portion 69b2 are formed of a metal such as aluminum. A part of the outer conductor 84a is the housing 42a1 of the second resonator 42a, and the housing 42a1 is at ground potential together with the grounded processing chamber 3. In addition, a portion 69b3 of the housing 42a1 other than the movable range of the ground fin 75 is filled with a dielectric material such as PTFE.

[0052] The outer conductor 84a has a cylindrical shape, and an input port P2 is formed on a side surface 69b1 of the second resonator 42a. A sustaining power supply port 46a that functions as an output port is formed on the end of the outer conductor 84a near the side where the input port P2 is formed, and the other end 69b2 is formed in a disk shape so as to close the cylinder. A rod-shaped portion 74 for moving the ground fin 75 in the left-right direction in FIG. 3 penetrates the center of the end 69b2.

[0053] A ground fin 75 is provided inside the housing 42a1. The ground fin 75 has a plurality of fins 76 and a rod-shaped portion 74. The plurality of fins 76 and the rod-shaped portion 74 are formed of a conductor such as aluminum. The plurality of fins 76 have, for example, a concentric columnar and cylindrical shape. The second resonator 42a is a comb-shaped resonator in which the plurality of fins 76 have a comb-shaped cross section shown in FIG. 3.

[0054] A plurality of fins 77 are provided inside the housing 42a1. The plurality of fins 77 are a triple cylindrical multipole antenna. The plurality of fins 77 are comb-shaped in the cross section shown in FIG.

[0055] The sides of the multiple fins 77 are fixed to a cylindrical base 73. The fins 77 and the base 73 are made of a conductor such as aluminum. The ground fins 75 are slidable, and even when the ground fins 75 are inserted deepest toward the fins 77, they do not come into contact with the fins 77. By sliding the ground fins 75, the insertion amount of the fins 76 into the fins 77 is changed. By changing the insertion amount of the ground fins 75 (fins 76) in this way to change the size of the resonance space, the resonance frequency of the second resonator 42a can be controlled to match the frequency of the microwaves, and the plasma can be maintained and controlled.

[0056] 3, the gap from the tips of the fins 76 to the surface of the base 73 to which the fins 77 are fixed is defined as X2. The gap from the tips of the fins 77 to the surface of the ground fin 75 to which the fins 76 are fixed may also be defined as X2.

[0057] An alumina ring member 54b is disposed near the maintenance power supply port 46a, which is fitted into a hollowed-out portion of the housing 40. The ring member 54b is adjacent to the conductor power supply portion 70a. The ring member 54b functions as the maintenance power supply port 46a. Microwave power passes through the connection portion 73a, the second resonator 42a, the power supply portion 70a, the slot antenna 71 (slot 71a), and penetrates the dielectric 72 to be supplied into the housing 40.

[0058] As a result, the gas introduced from the gas inlet 40a is decomposed by the energy of the microwaves, and plasma is maintained in the plasma generation chamber U. By arranging the maintenance power supply port 46a and the second resonator 42a on the path V connecting the gas inlet 40a and the supply port 40b, plasma can be efficiently maintained in the plasma generation chamber U.

[0059] The first resonator 41b has the same structure as the first resonator 41a, and the second resonator 42b has the same structure as the second resonator 42a, so a description thereof will be omitted here.

[0060] Next, an example of connection between the plasma source 2 and the microwave power supply 48 will be described with reference to Fig. 2. The plasma source 2 has a power supply unit 4. The power supply unit 4 has a microwave power supply 48, a switching unit 47, and cables 79 and 89. The first resonators 41a and 41b are connected to the microwave power supply 48 via the cable 79. The second resonators 42a and 42b are connected to the microwave power supply 48 via the cable 89.

[0061] The switching unit 47 switches between electrical connections between the ignition power supply ports 45a, 45b and the first resonators 41a, 41b and the microwave power supply 48, and electrical connections between the maintenance power supply ports 46a, 46b and the second resonators 42a, 42b and the microwave power supply 48.

[0062] When igniting plasma, the switching unit 47 connects the microwave power supply 48 to the first resonators 41a, 41b via the cable 79. When maintaining plasma, the switching unit 47 connects the microwave power supply 48 to the second resonators 42a, 42b via the cable 89. This makes it possible to use one microwave power supply 48 to supply microwave power to the first resonators 41a, 41b when igniting plasma, and to supply microwave power to the second resonators 42a, 42b when maintaining plasma.

[0063] The microwave power supply 48 is an example of a high frequency power supply that supplies high frequency power, and is a fixed frequency power supply, not a variable frequency power supply. The microwave frequency band is 300 MHz to 300 GHz. The high frequency power supply may include a VHF wave with a frequency band of 150 MHz to 300 MHz. That is, the high frequency power supply supplies high frequency power including microwaves and VHF waves. In this specification, the fixed frequency power supply includes not only a high frequency output power supply with a single frequency but also an output power supply that can vary a narrow frequency band of about ±10 MHz to ±20 MHz from the single frequency, and the fixed frequency power supply according to this embodiment includes an output power supply that can vary such a narrow frequency band. In other words, a power supply that can both ignite and maintain plasma by changing the output frequency is defined as a variable frequency power supply, and a narrow band power supply that can only ignite or maintain plasma is defined as a fixed frequency power supply.

[0064] With this configuration, it is possible to further miniaturize the plasma source 2 by providing comb-shaped resonators in the first resonator 41 and the second resonator 42 without using a matching box that would be large. This makes it possible to ignite and maintain plasma in the miniaturized plasma source 2 and send active species in the plasma to the processing chamber 3.

[0065] The matching box performs both impedance matching when plasma is ignited and when plasma is maintained. The impedance to be matched when plasma is ignited is quite different from the impedance to be matched when plasma is maintained. For this reason, when performing both impedance matching, the matching box circuit has to be enlarged, which increases the cost.

[0066] Fig. 4 is a diagram showing an example of the relationship between the structural height and the resonant frequency when plasma is ignited and when plasma is maintained. The horizontal axis of Fig. 4 indicates the gap indicated by X, which is the structural height X1 and X2 (mm) of the first resonator 41 and the second resonator 42 shown in Fig. 3. The vertical axis of Fig. 4 indicates the resonant frequency (MHz).

[0067] Line P1 indicates the resonance frequency at which plasma can be ignited for the structural height X and at which the efficiency of supplying microwave power of a predetermined frequency is highest when plasma is ignited. Line P2 indicates the resonance frequency at which plasma can be maintained for the structural height X and at which the efficiency of supplying microwave power of a predetermined frequency is highest when plasma is maintained.

[0068] According to this, when the structural height X is the same, the resonant frequency during plasma ignition and the resonant frequency during plasma maintenance are shifted by about 150 MHz to 200 MHz. Therefore, if plasma ignition and plasma maintenance are performed using the same resonator, the difference between the structural height X during plasma ignition and the structural height X during plasma maintenance becomes large, making it impossible to create the resonator structurally or to reduce its size.

[0069] On the other hand, using a variable frequency power supply that variably controls the frequency band of 150 MHz to 200 MHz for microwave power supply 48 is technically difficult, and microwave power supply 48 becomes large and expensive, making it unrealistic.

[0070] Therefore, in the plasma source 2 according to this embodiment, a first resonator 41 for plasma ignition and a second resonator 42 for plasma maintenance are separately prepared, and microwaves of a single frequency are supplied by the two different resonators.

[0071] For example, when the frequency of the microwaves output from the microwave power supply 48 is a single frequency of 810 MHz as indicated by the dotted line in FIG. 4, the structural height X1 of the first resonator 41a is adjusted to 4.8 mm, and the structural height X2 of the second resonator 42a is adjusted to 0.5 mm.

[0072] In this way, the structural height X1 of the first resonator 41 and the structural height X2 of the second resonator 42 are adjusted to the appropriate structural height X that is the resonant frequency. In this way, by separately preparing the first resonator 41 for plasma ignition and the second resonator 42 for plasma maintenance, the first resonator 41 and the second resonator 42 can be made smaller, and the cost can be reduced. In addition, the first resonator 41 and the second resonator 42 have semi-fixed resonant frequencies, that is, they are semi-fixed types in which the positions of the comb teeth are adjusted by screws, so that they can be made smaller. For example, the first resonator 41 and the second resonator 42 can be made about 1 / 4 the size of a conventional matching device.

[0073] The first resonator 41 and the second resonator 42 may have the same structure, and only the structural height X of the comb teeth may be adjusted. Alternatively, the first resonator 41 and the second resonator 42 may be optimized for ignition and maintenance by optimizing the dimensions of the comb teeth, such as the width and length, and then adjusting the structural height X of the comb teeth.

[0074] [Variation 1] A modified example of the plasma source 2 according to the first embodiment will be described with reference to Fig. 5. The difference from the plasma source 2 according to the first embodiment shown in Fig. 2 is that the first resonator 41 in Fig. 2 is replaced with an antenna including a matching device 80, and the other configurations are the same. Therefore, only the antenna including the matching device 80 will be described, and descriptions of the other configurations will be omitted.

[0075] In the plasma source 2 of the modified example, an antenna unit including a matching box 80 for ignition that can match frequencies over a relatively wide band is used. In the modified example, the matching box 80 configured to be able to ignite plasma is attached to the ignition power supply port 45.

[0076] The antenna section has a matching box 80 for matching impedance, and a radiation section 85 for radiating microwaves into the housing 40. Furthermore, the antenna section has a cylindrical main container 87 made of a metal material and extending laterally, and an inner conductor 88 extending within the main container 87 in the same direction as the main container 87 extends. The main container 87 and the inner conductor 88 form a coaxial tube. The main container 87 is cylindrical, and forms the outer conductor of the coaxial tube. The inner conductor 88 is rod-shaped or cylindrical. The space between the inner peripheral surface of the main container 87 and the outer peripheral surface of the inner conductor 88 forms the microwave transmission path 82.

[0077] A plurality of ring-shaped dielectrics 86, through which inner conductors 88 penetrate, are arranged in the microwave transmission line 82. The dielectrics 86 are made of ceramics or the like, and are connected to a motor (not shown). The dielectrics 86 move left and right within the microwave transmission line 82 when driven by the motor. In this way, the matching box 80 performs impedance matching when plasma is ignited.

[0078] In the plasma source 2 according to the modification, the antenna unit including the matching device 80 is used when the plasma is ignited, and the second resonator 42 is used when the plasma is maintained. That is, when the plasma is ignited, the switching unit 47 connects the microwave power source 48 and the antenna unit including the matching device 80 via the cable 79. When the plasma is maintained, the switching unit 47 connects the microwave power source 48 and the second resonators 42a and 42b via the cable 89. This allows one microwave power source 48 to supply microwave power to the antenna unit including the matching device 80 when the plasma is ignited, and to supply microwave power to the second resonators 42a and 42b when the plasma is maintained. This allows the antenna unit including the matching device 80 to be larger than the first resonator 41, but only needs to match impedance when the plasma is ignited. In other words, it is not necessary to match impedance when the plasma is maintained, and this allows the size and cost to be reduced. This allows the plasma source 2 to be made smaller.

[0079] <Second embodiment> [Plasma processing equipment] A plasma processing apparatus 10a according to a second embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a cross-sectional perspective view showing an example of the plasma processing apparatus 10a according to the second embodiment. Fig. 7 is a view showing a ceiling surface of the plasma processing apparatus 10a according to the second embodiment.

[0080] The plasma processing apparatus 10a shown in FIGS. 6 and 7 includes a chamber 120, a mounting table 121, a gas supply source 131, an exhaust device 140, a first resonator 141, second resonators 142a to 142f, and a control unit 180. The chamber 120 accommodates a substrate W, for example a wafer. The mounting table 121 is disposed inside the chamber 120 and has a mounting surface 121a on which the substrate W is mounted. The gas supply source 131 supplies gas into the chamber 120. The exhaust device 140 exhausts the inside of the chamber 120 to reduce the pressure. The first resonator 141 and the second resonators 142a to 142f introduce microwaves, which generate plasma from the gas supplied into the chamber 120. The control unit 180 controls each unit of the plasma processing apparatus 10a. The second resonators 142a to 142f are also collectively referred to as second resonators 142.

[0081] The chamber 120 has, for example, a cylindrical shape. The chamber 120 is formed of a metal material such as aluminum or an alloy thereof. The chamber 120 has a plate-shaped top wall 111, a bottom wall 113, and a side wall 112 connecting the top wall 111 and the bottom wall 113. The top wall 111, which is a conductive member, is disposed at the top of the chamber 120 and has a plurality of openings. The first resonator 141 and the second resonators 142a to 142f are disposed above the top wall 111 of the chamber 120, and supply microwave power into the chamber 120.

[0082] The side wall 112 has a loading / unloading opening 112a for loading / unloading the substrate W between the chamber 120 and a transfer chamber (not shown) adjacent to the chamber 120. A gate valve G is disposed between the chamber 120 and the transfer chamber (not shown). The gate valve G has a function of opening and closing the loading / unloading opening 112a. When in a closed state, the gate valve G air-tightly seals the chamber 120, and when in an open state, allows the substrate W to be transferred between the chamber 120 and the transfer chamber.

[0083] The bottom wall 113 has a plurality of exhaust ports 113a (two in FIG. 1). The exhaust ports 113a and the exhaust device 140 are connected by an exhaust pipe 114. The exhaust device 140 has an APC valve and a high-speed vacuum pump capable of reducing the pressure of the internal space of the chamber 120 to a predetermined vacuum level. An example of the high-speed vacuum pump is a turbo molecular pump. By operating the high-speed vacuum pump of the exhaust device 140, the internal space of the chamber 120 is reduced in pressure to a predetermined vacuum level.

[0084] The plasma processing apparatus 10a further includes a support member 122 that supports the mounting table 121 in the chamber 120, and an insulating member 123 provided between the support member 122 and the bottom wall 113. The mounting table 121 is for horizontally mounting the substrate W. When the substrate W is loaded and unloaded, it is lifted by lift pins 119 raised by a lifting mechanism (not shown), and the substrate W is transferred between the transport mechanism and the mounting table 121. The support member 122 has a cylindrical shape extending from the center of the bottom wall 113 toward the internal space of the chamber 120. The mounting table 121 and the support member 122 are formed of, for example, aluminum having a surface that has been anodized (anodized).

[0085] The plasma processing apparatus 10a further includes a high frequency bias power supply 125 that supplies high frequency power to the mounting table 121, and a matching box 124 provided between the mounting table 121 and the high frequency bias power supply 125. The high frequency bias power supply 125 applies high frequency power to the mounting table 121 in order to attract ions to the substrate W. The matching box 124 includes a circuit for matching the output impedance of the high frequency bias power supply 125 with the impedance on the load side (the mounting table 121 side). The plasma processing apparatus 10a may further include a temperature control mechanism (not shown) that heats or cools the mounting table 121.

[0086] Gas supply source 131 is connected to piping 132, and the type and flow rate of gas supplied from gas supply source 131 are controlled by a mass flow controller and an opening / closing valve (not shown). Gas nozzle 102 extending from piping 132 has a cylindrical shape and penetrates ceiling wall 111. The tip of gas nozzle 102 is inserted inside chamber 120. Gas nozzle 102 supplies gas and the like into chamber 120 from gas supply hole 102a at its tip.

[0087] In Fig. 7, the gas nozzle is omitted. As shown in Figs. 6 and 7, the first resonator 141 and the second resonators 142a to 142f are connected to a microwave power supply 151 via cables 152 and 153. The microwave power supply 151 distributes microwaves to a plurality of paths and outputs them. The microwave power supply 151 has a switching unit (see the switching unit 47 in Fig. 2) and may switch between a plurality of paths and output the microwaves. The first resonator 141 radiates the microwaves output from the microwave power supply 151 into the chamber 120 via a slot antenna (not shown) embedded in the top wall 111 and a dielectric.

[0088] The first resonator 141 is provided at the center of the top wall 111 that constitutes the wall surface of the chamber 120. Six second resonators 142a to 142f are evenly arranged in the peripheral area of ​​the top wall 111. The second resonators 142a to 142f may be comb-shaped resonators. The first resonator 141 may be arranged on the side wall 112 that constitutes the wall surface of the chamber 120.

[0089] Each component of the plasma processing apparatus 10a is connected to and controlled by a control unit 180. The control unit 180 may be a computer having a processor and a memory. The control unit 180 includes a calculation unit, a storage unit, an input device, a display device, a signal input / output interface, and the like. The control unit 180 controls each component of the plasma processing apparatus 10a.

[0090] In the plasma processing apparatus 10a, when a microwave having a single frequency of 860 MHz is supplied into the chamber 120, the first resonator 141 is used for plasma ignition, and the second resonators 142a to 142f are used for plasma maintenance.

[0091] For example, when igniting plasma, the switching unit connects microwave power supply 151 and first resonator 141 via cable 152. When maintaining plasma, the switching unit connects microwave power supply 151 and second resonators 142a to 142f via cable 153. This makes it possible to use one microwave power supply 151 to supply microwave power from first resonator 141 so as to be able to ignite plasma when igniting plasma, and to supply microwave power from second resonators 142a to 142f so as to be able to maintain plasma when maintaining plasma.

[0092] In the plasma processing apparatus 10a, uniformity of the plasma generated in the chamber 120 is maintained, thereby enabling uniform plasma processing to be performed on the substrate W. Therefore, the number of second resonators 142 is not limited to six, but is preferably three or more, and as many as are required to maintain uniform plasma.

[0093] For example, an antenna unit including a matching device 80 shown in FIG. 5 may be disposed in the center of the top wall 111, and six second resonators 142 may be disposed in the peripheral region. When a microwave with a single frequency of 860 MHz is supplied into the chamber 120, the matching device 80 of the antenna unit matches the impedance at the time of plasma ignition, and after ignition, matches the impedance at the time of plasma maintenance. The second resonators 142a to 142f adjust the structural height of the second resonators 142a to 142f so that the frequency of the microwave power becomes an appropriate frequency (resonant frequency) for maintaining the plasma. This allows the uniformity of the plasma to be further improved by using the matching device 80 and the second resonators 142a to 142f at the time of plasma maintenance. The matching device 80 of the antenna unit can be used for both impedance matching at the time of plasma ignition and impedance matching at the time of plasma maintenance.

[0094] As described above, according to the plasma source 2 and the plasma processing apparatus 10, 10a of this embodiment, the plasma source can be made smaller in size.

[0095] The plasma source and the plasma processing apparatus according to the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. For example, in the first embodiment, the ring member 54a on the first resonator 41a side and the ring member 54b on the second resonator 42a side function as the ignition power supply ports 45a and 45b. However, the "ignition power supply port" is not limited to the ring member 54a, etc., and it goes without saying that anything can function as a "port" capable of supplying ignition power to the inside of the housing 40, and the same is true for the maintenance power supply port. The embodiments can be modified and improved in various forms without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can have other configurations within a range not contradictory, and can be combined within a range not contradictory. [Explanation of symbols]

[0096] 2. Plasma Source 3 Processing chamber 4 Power supply section 10, 10a Plasma treatment device 23 Connecting part 30e Plasma treatment chamber 47 Switching section 48 Microwave Power Supply 80 Matching box

Claims

1. a housing defining a plasma generation chamber; a gas inlet port provided in the housing for introducing a gas; a supply port provided in the housing for supplying active species of plasma generated from the gas in the plasma generation chamber; an ignition power supply port provided in the housing for supplying high frequency power for igniting plasma in the plasma generation chamber; a sustaining power supply port provided in the housing for supplying high frequency power for sustaining the plasma ignited in the plasma generation chamber; The plasma source has a

2. The ignition power supply port is provided with a first resonator or a matching device configured to ignite the plasma.

10. The plasma source of claim 1.

3. The sustaining power supply port is provided with a second resonator configured to sustain the plasma.

10. The plasma source of claim 1.

4. The sustaining power supply port is a plurality of ports; A plurality of the second resonators are provided in the plurality of the maintenance power supply ports. The plasma source of claim 3.

5. the gas inlet and the gas supply port are disposed opposite to each other on the housing, At least one of the ignition power supply port and the maintenance power supply port is provided on a path connecting the gas inlet and the supply port. A plasma source according to any one of claims 1 to 4.

6. The first resonator is a comb resonator. The plasma source of claim 2 .

7. The second resonator is a comb resonator. The plasma source of claim 3.

8. a high frequency power source that supplies high frequency power for igniting the plasma and high frequency power for maintaining the plasma; The high frequency power supply is a fixed frequency power supply. A plasma source according to any one of claims 1 to 4.

9. a switching unit connected to the high frequency power supply and switching electrical connections between the ignition power supply port and the maintenance power supply port and the high frequency power supply; 9. The plasma source of claim 8.

10. The ignition power supply port and the maintenance power supply port are provided at opposing positions on a side surface of the housing. A plasma source according to any one of claims 1 to 4.

11. A plasma source; a process chamber defining a plasma processing chamber; a connection between the plasma source and the processing chamber; The plasma source comprises: a housing defining a plasma generation chamber; a gas inlet port provided in the housing for introducing a gas; a supply port provided in the housing for supplying activated species of plasma generated from the gas in the plasma generation chamber to the plasma processing chamber; an ignition power supply port provided in the housing for supplying high frequency power for igniting plasma in the plasma generation chamber; a sustaining power supply port provided in the housing for supplying high frequency power for sustaining the plasma ignited in the plasma generation chamber; The plasma processing apparatus comprises:

12. a process chamber defining a plasma processing chamber; a gas supply hole provided in the processing chamber for supplying a gas; an ignition power supply port formed on a wall surface of the processing chamber for supplying high frequency power to the plasma processing chamber for igniting plasma from the gas; a sustaining power supply port formed in a ceiling wall of the processing chamber for supplying high frequency power for sustaining the plasma ignited in the plasma processing chamber; a first resonator or matching device provided at the ignition power supply port and configured to ignite the plasma; a second resonator provided at the sustain power supply port and configured to sustain the plasma; The plasma processing apparatus comprises:

13. The ignition power supply port is formed in the center of the top wall, The first resonator is provided at the ignition power supply port. The plasma processing apparatus according to claim 12 .

14. The sustaining power supply port is formed in a plurality of ports on the outer periphery of the top wall closer to the ignition power supply port, A plurality of the second resonators are provided in the plurality of the maintenance power supply ports. The plasma processing apparatus according to claim 13 .

15. the first resonator and the second resonator are interdigital resonators; The plasma processing apparatus according to any one of claims 12 to 14.

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