阅读说明：本技术 等离子体处理方法和等离子体处理装置 (Plasma processing method and plasma processing apparatus ) 是由 镰田英纪 佐藤干夫 池田太郎 山本伸彦 于 2020-03-23 设计创作，主要内容包括：本发明提供一种等离子体处理装置中的等离子体处理方法,所述等离子体处理装置包括腔室、用于在所述腔室内载置基片的载置台、用于辐射多个电磁波的多个辐射部、和配置在多个所述辐射部与所述载置台之间的电介质窗,所述等离子体处理方法的特征在于,包括：在所述载置台上准备基片的工序；控制从多个所述辐射部辐射的多个所述电磁波中的至少任一个电磁波的相位的工序；从多个所述辐射部向所述腔室内辐射多个所述电磁波的工序；和利用从被供给到所述电介质窗与所述载置台之间的气体生成的局部等离子体对所述基片进行处理的工序。(The present invention provides a plasma processing method in a plasma processing apparatus including a chamber, a mounting table for mounting a substrate in the chamber, a plurality of radiation portions for radiating a plurality of electromagnetic waves, and a dielectric window arranged between the plurality of radiation portions and the mounting table, the plasma processing method comprising: preparing a substrate on the mounting table; a step of controlling a phase of at least any one of the electromagnetic waves radiated from the plurality of radiation portions; a step of radiating the plurality of electromagnetic waves from the plurality of radiation units into the chamber; and processing the substrate by using local plasma generated from the gas supplied between the dielectric window and the mounting table.)

1. A plasma processing method in a plasma processing apparatus including a chamber, a mounting table for mounting a substrate in the chamber, a plurality of radiation portions for radiating a plurality of electromagnetic waves, and a dielectric window arranged between the plurality of radiation portions and the mounting table, the plasma processing method comprising:

preparing a substrate on the mounting table;

a step of controlling a phase of at least any one of the electromagnetic waves radiated from the plurality of radiation portions;

a step of radiating the plurality of electromagnetic waves from the plurality of radiation units into the chamber; and

and processing the substrate by using local plasma generated from the gas supplied between the dielectric window and the mounting table.

2. The plasma processing method according to claim 1, wherein:

the dielectric window is disposed at intervals from the plurality of radiation portions and the mounting table,

the plasma processing method includes a step of propagating a plurality of the electromagnetic waves in a space above the dielectric window,

in the step of processing the substrate, the local plasma is generated in a space below the dielectric window.

3. The plasma processing method according to claim 2, wherein:

the vertical distance from the plurality of radiating portions to the dielectric window is greater than 1/4 of the wavelength λ of the electromagnetic wave.

4. The plasma processing method according to any one of claims 1 to 3, wherein:

the plurality of radiation portions each have a monopole antenna.

5. The plasma processing method according to any one of claims 1 to 4, wherein:

a distance from the center of the radiation section to the center of the adjacent radiation section is less than 1/2 of the wavelength λ of the electromagnetic wave.

6. The plasma processing method according to any one of claims 1 to 5, wherein:

the frequency of the plurality of electromagnetic waves is 100MHz or more.

7. The plasma processing method according to claim 6, wherein:

the frequency of the electromagnetic waves is 1 GHz-3 GHz.

8. The plasma processing method according to any one of claims 1 to 7, wherein:

changing the phase of a plurality of the electromagnetic waves over time controls the region where the local plasma is generated.

9. A plasma processing apparatus comprising a chamber, a mounting table for mounting a substrate in the chamber, a plurality of radiation portions for radiating a plurality of electromagnetic waves, a dielectric window disposed between the plurality of radiation portions and the mounting table, and a control device, wherein the control device controls the steps of:

preparing a substrate on the mounting table;

a step of controlling a phase of at least any one of the electromagnetic waves radiated from the plurality of radiation portions;

a step of radiating the plurality of electromagnetic waves from the plurality of radiation units into the chamber; and

and processing the substrate by using local plasma generated from the gas supplied between the dielectric window and the mounting table.

Technical Field

The present invention relates to a plasma processing method and a plasma processing apparatus.

Background

A plasma processing apparatus is known which converts a gas into plasma by using power of an electromagnetic wave to perform plasma processing on a wafer. For example, patent document 1 proposes a plasma processing apparatus including: a process chamber capable of generating a plasma; a vacuum window forming a portion of a wall of the process chamber; an induction antenna which is arranged outside the dielectric of the vacuum window and is used for generating plasma in the processing chamber, and the induction antenna is composed of at least 2 systems; a high-frequency power supply for independently supplying current to each system of the induction antenna; and a control unit including a phase circuit or a control device for controlling a phase or a current value of the current of the high-frequency power supply of each system in time. The control unit in patent document 1 continuously time-modulates the phase difference or the current value between the currents flowing through the respective systems during the processing time of the sample, and moves the plasma generation position so that the incident angle of the ions incident on the wafer becomes the same in the wafer plane.

For example, patent document 2 proposes a method of correcting a reaction speed on a semiconductor substrate in a processing chamber using a phased array microwave antenna, in which plasma is excited in the processing chamber, a microwave radiation beam is radiated from the phased array of microwave antennas, and the microwave radiation beam is directed toward the plasma, so that the reaction speed on the surface of the semiconductor substrate in the processing chamber varies.

For example, patent document 3 proposes: the microwave output from the microwave output unit is radiated from the antenna into the chamber, and an electric field for generating surface wave plasma is formed in the dielectric member through which the microwave radiated from the antenna is transmitted. In patent document 3, at least one of the power of the microwave radiated to the microwave radiation mechanism and the phase of the microwave is controlled based on the electron temperature Te of the plasma and the electron density Ne of the plasma.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-53172

Patent document 2: japanese patent laid-open publication No. 2017-103454

Patent document 3: japanese laid-open patent publication No. 2018-181634

Disclosure of Invention

Technical problem to be solved by the invention

The invention provides a plasma processing method and a plasma processing apparatus capable of changing electric field distribution in a dielectric window without depending on arrangement of a plurality of electromagnetic wave radiation mechanisms.

Means for solving the problems

According to one aspect of the present invention, there is provided a plasma processing method in a plasma processing apparatus including a chamber, a mounting table for mounting a substrate in the chamber, a plurality of radiation portions for radiating a plurality of electromagnetic waves, and a dielectric window disposed between the plurality of radiation portions and the mounting table, the plasma processing method comprising: preparing a substrate on the mounting table; a step of controlling a phase of at least any one of the electromagnetic waves radiated from the plurality of radiation portions; a step of radiating the plurality of electromagnetic waves from the plurality of radiation units into the chamber; and processing the substrate by using local plasma generated from the gas supplied between the dielectric window and the mounting table.

Effects of the invention

With one aspect of the present invention, it is possible to change the electric field distribution in the dielectric window without depending on the configuration of the plurality of electromagnetic wave radiation mechanisms.

Drawings

Fig. 1A is a schematic cross-sectional view showing an example of a plasma processing apparatus of a comparative example.

Fig. 1B is a schematic cross-sectional view showing an example of a plasma processing apparatus according to an embodiment.

Fig. 2 is a diagram showing an example of an electromagnetic wave radiation mechanism according to an embodiment.

Fig. 3 is a diagram for explaining phase control according to an embodiment.

Fig. 4 is a diagram showing an example of phase control by the control device according to the embodiment.

Fig. 5 is a flowchart showing an example of a plasma processing method according to one embodiment.

Fig. 6A is a diagram showing an example of electric field distribution in the dielectric window according to the embodiment.

Fig. 6B is a diagram showing an example of electric field distribution in the dielectric window according to the embodiment.

Fig. 6C is a diagram showing an example of electric field distribution in the dielectric window according to the embodiment.

Detailed Description

The following describes a mode for carrying out the present invention with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and redundant description thereof may be omitted.

[ plasma processing apparatus ]

A plasma processing apparatus 10 according to one embodiment will be described with reference to fig. 1A and 1B. Fig. 1A is a schematic cross-sectional view showing an example of a plasma processing apparatus 20 of a comparative example, and fig. 1B is a schematic cross-sectional view showing an example of a plasma processing apparatus 10 of an embodiment. The plasma processing apparatuses 10 and 20 will be described by taking a microwave plasma processing apparatus as an example. The plasma processing apparatus 20 of the comparative example of fig. 1A (a) does not have a phaser.

The plasma processing apparatus 10 according to one embodiment of fig. 1B (a) has a chamber 1 for housing a wafer W. The plasma processing apparatus 10 can perform a predetermined plasma process such as a film forming process or an etching process on the wafer W by using surface wave plasma formed by a microwave.

The chamber 1 is a substantially cylindrical processing container and is grounded. In the chamber 1, an upper opening provided at the top is closed by a ceiling plate 9, whereby the inside can be kept airtight. The chamber 1 and the ceiling 9 are formed of a metal material such as aluminum or stainless steel.

A mounting table 3 on which a wafer W is mounted is supported by a cylindrical support member 4 which is vertically provided with an insulating member interposed therebetween at the center of the bottom in the chamber 1. Examples of the material constituting the mounting table 3 include a metal such as aluminum having an alumite treated (anodized) surface, and an insulating member (such as ceramic) having an electrode for high frequency inside. The mounting table 3 may be provided with an electrostatic chuck for electrostatically attracting the wafer W, a temperature control mechanism, a gas flow path for supplying a heat transfer gas to the back surface of the wafer W, and the like.

The mounting table 3 may be electrically connected to a high-frequency bias power source via a matching box. By supplying high-frequency power from the high-frequency bias power supply to the stage 3, ions in the plasma can be introduced to the wafer W. However, the high-frequency bias power supply may not be provided depending on the characteristics of the plasma processing.

An exhaust pipe is connected to the bottom of the chamber 1, and an exhaust device including a vacuum pump is connected to the exhaust pipe. When the evacuation device is operated, the chamber 1 can be evacuated, and thereby the chamber 1 can be depressurized to a predetermined vacuum degree. A loading/unloading port for loading and unloading the wafer W and a gate valve for opening and closing the loading/unloading port are provided in a side wall of the chamber 1.

On the top plate 9, 7 electromagnetic wave radiation means 2 (only 3 electromagnetic wave radiation means 2 are illustrated in fig. 1B (a)) for radiating microwaves into the chamber 1 are provided.

[ monopole antenna ]

Fig. 2 shows an example of the electromagnetic wave radiation mechanism 2. The electromagnetic wave radiation mechanism 2 is in the form of a coaxial cable, and includes an inner conductor 121, an outer conductor 122 outside the inner conductor, and a dielectric 123 such as Teflon (registered trademark) provided therebetween. The front end of the electromagnetic wave radiation means 2 constitutes a monopole antenna 11 formed of an inner conductor 121 that protrudes by a length D.

The monopole antenna 11 is configured such that the inner conductor 121 is exposed from the end surface of the dielectric member 123 having the same height as the rear surface 9a of the ceiling 9 of the chamber 1 to form the radiation section 125 in the internal space of the chamber 1, and thereby microwaves can be radiated from the radiation section 125 into the chamber 1. The length D of the radiation portion 125 varies according to the frequency of the electromagnetic wave. For example, when the frequency of the microwave is 300MHz to 3GHz, the length D is several 10mm to several 100 mm. However, the inner conductor 121 may not protrude from the dielectric 123. In this case, a notch portion where the outer conductor 122 does not exist is formed at the front end of the electromagnetic wave radiation mechanism 2, and the microwave is radiated into the chamber 1 from the radiation port at the front end of the inner conductor 121 through the notch portion.

With the above configuration, the microwave is output from the microwave output unit 6, subjected to phase control by the phase shifter 7 under the control of the control device 8, and then radiated into the chamber 1. The number of the electromagnetic wave radiation means 2 is not limited to 7, and may be 2 or more, preferably 3 or more.

Returning to fig. 1B (a), the distances E from the center of the electromagnetic wave radiation means 2 to the center of the adjacent electromagnetic wave radiation means 2 are regularly arranged at substantially equal intervals so as to be smaller than 1/2 of the wavelength λ of the microwave. The dielectric window 5 is disposed at a distance from the plurality of radiation portions 125 and the mounting table 3. The dielectric window 5 becomes a partition plate that divides the inside of the chamber 1 into a space V above the dielectric window 5 and a space U below the dielectric window 5. The dielectric window 5 is made of, for example, quartz or alumina (Al)₂O₃) Such as ceramics, fluorine-based resins such as polytetrafluoroethylene, or polyimide-based resins.

In the space V below the electromagnetic wave radiation means 2, there is a free space of about 10mm to 100mm, and plasma can be generated in the space U through the dielectric window 5 provided below the free space. The vertical distance H between the rear surface 9a of the top plate 9 and the upper surface of the dielectric window 5 is larger than λ/4 with respect to the wavelength λ of the microwave. A plurality of microwaves radiated from the 7 electromagnetic wave radiation mechanisms 2 propagate in the space V. The space V is an atmospheric space, and the space U is a vacuum space.

The plasma processing apparatus 10 has a control device 8. The control device 8 may be a computer having a storage unit such as a processor and a memory, an input device, a display device, and an input/output interface for signals. The control device 8 controls each part of the plasma processing apparatus 10. The control device 8 uses an input device, and an operator can perform an input operation of a command for managing the plasma processing apparatus 10. In addition, the control device 8 can visually display the operating state of the plasma processing apparatus 10 by using a display device. The storage unit stores a control program and scenario data. The control program may be executed by the processor in order to execute various processes in the plasma processing apparatus 10. The processor executes the control program and controls the respective parts of the plasma processing apparatus 10 according to the recipe data. The processor of the control device 8 can control the phase shifter 7 provided for each electromagnetic wave radiation mechanism 2, and can control the phase of the microwave radiated from the radiation unit 125.

When performing plasma processing in the plasma processing apparatus 10 having the above-described configuration, first, the wafer W is carried into the chamber 1 through the carrying-in/out port from the opened gate valve while being held by the transfer arm.

The gate valve is closed after the wafer W is fed. When the wafer W is transferred to the upper side of the mounting table 3, the transfer arm is moved to a pin (pusher pin), and the pin is lowered to be mounted on the mounting table 3. The pressure inside the chamber 1 is maintained at a predetermined degree of vacuum by the evacuation device. A predetermined gas is introduced into the space U below the dielectric window 5. The microwaves of which phases are controlled are radiated from the 7 electromagnetic wave radiation mechanisms 2 (monopole antennas 11). This strengthens the electric field at the predetermined position of the dielectric window 5, and can control the distribution of plasma when the gas is turned into plasma. The generated plasma can be used to perform a predetermined plasma process on the wafer W.

In the plasma processing apparatus 20 of the comparative example shown in fig. 1A (a), the phases of the microwaves radiated from the 7 electromagnetic wave radiation means 2 are the same, as illustrated by the curve of the thick line in the electromagnetic wave radiation means 2. Therefore, in the plasma processing apparatus 20 of the comparative example, when plasma is generated below the dielectric window 5 by the electric field of the microwave, the electric field distribution is affected by the arrangement pattern (arrangement pattern) of the 7 electromagnetic wave radiation mechanisms 2. As a result, as illustrated in fig. 1A (b), the intensity of the plasma distribution is generated according to the arrangement pattern of the electromagnetic wave radiation means 2. That is, the plasma processing on the wafer W is affected by the arrangement pattern of the electromagnetic wave radiation mechanism 2, and tends to be uneven.

However, the arrangement pattern of the electromagnetic wave radiation means 2 is a physical arrangement, and it is difficult to change from a preset arrangement. Therefore, in the present embodiment, the plasma processing apparatus 10 and the plasma processing method capable of controlling the plasma distribution by changing the electric field distribution in the dielectric window 5 without depending on the arrangement of the plurality of electromagnetic wave radiation mechanisms 2 are provided.

That is, the plasma processing apparatus 10 of the present embodiment shown in fig. 1B (a) can control the phases of the microwaves radiated from the 7 electromagnetic wave radiation mechanisms 2 by the control of the control device 8 using the phase shifters 7. Thereby, the microwaves radiated from the 7 electromagnetic wave radiation means 2 interfere with each other, and the electric field intensity can be increased at any position. This enables concentrated generation of plasma, thereby realizing high-level control of plasma distribution.

For example, in fig. 1B (a), the microwaves propagating through the space V interfere with each other by controlling the phases of the microwaves radiated from the 7 electromagnetic wave radiation means 2, and the electric field intensity of the microwaves increases on the left side of the dielectric window 5. As a result, as illustrated in fig. 1B (B), plasma can be generated intensively on the left side of the wafer W.

[ phase control ]

Next, the phase control of the microwave will be described with reference to fig. 3. Fig. 3 is a diagram for explaining phase control using the phaser 7, which is performed by the control device 8 provided in the plasma processing apparatus 10 according to the embodiment. Fig. 3 (a) shows a relationship between the microwave radiated from one of the electromagnetic wave radiation means 2 (in this example, the electromagnetic wave radiation means 2a) and the focal position O of the dielectric window 5 at which the electric field is to be concentrated. When the position of the back surface of the top plate 9 perpendicular to the focal position O is denoted by O ', the distance from the focal position O to the position O' of the back surface of the top plate 9 is denoted by z, and the position of the radiation point of the microwave radiated from the electromagnetic wave radiation mechanism 2a is denoted by x, the following expression (1) is established.

K in formula (1) is the wave number of the electromagnetic wave, and can be represented by the reciprocal of the wavelength λ of the electromagnetic wave, that is, k is 1/λ. δ (x) represents the phase of an electromagnetic wave (microwave in the present embodiment) radiated from the position x of the radiation point.

By modifying the formula (1), the formula (2) for obtaining the phase δ (x) of the electromagnetic wave can be obtained.

Based on equation (2), the phase δ (x) of the electromagnetic wave radiated from the position x of the radiation point can be calculated from the wave number k of the electromagnetic wave, the distance z from the position O of the dielectric window 5 to the position O' of the back surface of the top plate 9, and the position x of the radiation point. Equation (2) depicts the curve of fig. 3 (b).

The conditions for mutually increasing the phases at the focal position O of the microwaves radiated from the 2 or more electromagnetic wave radiation means 2 will be described with reference to (c) of fig. 3. Assuming that 7 electromagnetic wave radiation means 2 are electromagnetic wave radiation means 2a, 2b, 2c, 2d, 2e, 2f, 2g, in fig. 3 (c), they are shown as being arranged laterally at intervals, which is different from the actual positional relationship of the electromagnetic wave radiation means 2, for the sake of convenience of explanation.

Electromagnetic wave in the present embodimentIn the control of the radiation mechanisms 2a to 2g, the control device 8 controls the phase δ (x) of each microwave radiated from the electromagnetic wave radiation mechanisms 2a to 2g_a)～δ(x_g) So that the position x of each radiation point of the microwave radiated from the electromagnetic wave radiation mechanisms 2a to 2g_a～x_gThe respective distances to the focal position O make the phases at the focal position O uniform.

Since the positions x of the radiation points of the electromagnetic wave radiation means 2a to 2g are different from each other, as shown in formula (2), if the phase δ (x) of the microwave radiated from the electromagnetic wave radiation means 2a to 2g is not controlled, the phase is deviated from the focal position O. As a result, even if the phase of any one of the microwaves of the electromagnetic wave radiation means 2a to 2g is increased at the focal position O, the phase of any other microwave is decreased at the focal position O. In the present embodiment, the phase δ (x) of the microwave radiated from the electromagnetic wave radiation means 2a to 2g is adjusted by the phase_a)～δ(x_g) By performing the individual control, the phases of all the microwaves can be mutually intensified at the focal position O. For example, the phases of the microwaves radiated from the electromagnetic wave radiation mechanisms 2a, 2b, and 2c shown in fig. 3 (c) are set to be conditions for mutually strengthening the phases of the microwaves because the antinodes match the antinodes and the nodes match the nodes. However, even if the conditions are controlled such that the phases of the microwaves radiated from the electromagnetic wave radiation means 2a, 2b, and 2c are mutually intensified, the phase of at least one of the microwaves radiated from the electromagnetic wave radiation means 2d to 2g may be weakened, and the phase of the 7 microwaves mutually intensified at the focal position O may not be obtained.

In the present embodiment, the phases of the microwaves radiated from the electromagnetic wave radiation means 2d, 2e, 2f, and 2g are also controlled so as to be mutually intensified. Accordingly, the phase of each microwave is controlled so that the phases of 7 microwaves are mutually intensified at the focal position O of the dielectric window 5, whereby the electric field of the microwave can be controlled so as to be concentrated at the focal position O.

However, the control of mutually intensifying the phases of the microwaves at the focal position O may be performed on the lowest 2 microwaves output from the electromagnetic wave radiation means 2a to 2g, instead of performing the control of mutually intensifying the phases at the focal position O for all of the 7 microwaves. For example, the number of the electromagnetic wave radiation means 2 that do not control the phase of the microwave may be 1 or more. In the above description, the number of focal positions O in the dielectric window 5 is 1, but the present invention is not limited to this, and control may be performed to mutually strengthen the phases at 2 or more focal positions O in the dielectric window 5 at the same timing.

Further, as shown in (a) of fig. 1B, the distance E from the center of one electromagnetic wave radiation mechanism 2 to the center of the adjacent electromagnetic wave radiation mechanism 2 is smaller than λ/2. This is because, when the distance E (interval) between adjacent electromagnetic wave radiation means 2 is λ/2 or more, the focal point position O of the microwave focusing dielectric window 5 cannot be made, and control for mutually strengthening the phases of the microwaves at the focal point position O cannot be realized.

The convergence by the phase control described above does not involve the mechanical operation, and therefore can be controlled at high speed. In principle, the focal position O can be moved over time by high-speed control of the same degree as the frequency of the microwave. This enables the phase control of the plurality of electromagnetic wave radiation mechanisms 2 to be controlled at high speed. As a result, by controlling the electric field distribution of the microwave in the dielectric window 5 at a high speed, plasma can be uniformly generated in the space U below the dielectric window 5.

Fig. 4 is a diagram showing an example of phase control by the control device 8 according to the embodiment. In the example of fig. 4, the control device 8 controls the phase δ (x) of the microwaves radiated from the 7 electromagnetic wave radiation mechanisms 2a, 2b, 2c, 2d, 2e, 2f, 2g, respectively, using the phasers 7 (only one is shown in fig. 4)_a)～δ(x_g) So that the phases reinforce each other at the focal position C. This schematically shows a case where the electric field of the microwave is controlled so as to be stronger at the focal point position C at the convergent portion Ar.

The control device 8 controls the phase δ (x) of the microwave at high speed by using the phase shifter 7 so that the focal point position C is scanned over the surface of the dielectric window 5 in the radial direction L1 or the circumferential direction L2_a)～δ(x_g). Thereby, by moving the focal position C and the converging portion Ar at a high speed, plasma can be uniformly generated in the space U below the dielectric window 5.

The control device 8 controls the phase δ (x) of the microwave by the phase shifter 7_a)～δ(x_g) To change the moving speed of the convergent portion Ar, so that the average electric field distribution per unit time can be freely controlled. For example, the control device 8 may control the phase δ (x) of the microwave so that the focal point Ar is moved slowly on the outer peripheral side of the dielectric window 5 and the focal point Ar is moved faster on the inner peripheral side than on the outer peripheral side of the dielectric window 5_a)～δ(x_g) Is changed. This makes it possible to make the electric field intensity on the outer peripheral side of dielectric window 5 stronger than the electric field intensity on the inner peripheral side of dielectric window 5. This makes it possible to control the plasma density on the outer peripheral side below the dielectric window 5 to be higher than the plasma density on the inner peripheral side, and to freely control the plasma distribution.

[ plasma treatment method ]

Next, an example of a plasma processing method executed by the plasma processing apparatus 10 will be described with reference to fig. 5. Fig. 5 is a flowchart showing an example of a plasma processing method according to one embodiment. This process is controlled by the control device 8.

When the present process is started, the controller 8 loads the wafer W into the chamber and mounts the wafer W on the mounting table 3 to prepare the wafer W (step S1). Next, the controller 8 supplies a predetermined gas from the gas supply unit (step S2). Next, the control device 8 outputs microwaves from the microwave output unit 6 (step S3).

Next, the control device 8 controls the phase of each microwave radiated from the 7 electromagnetic wave radiation mechanisms 2 by using the phase shifter 7, and radiates each microwave whose phase is controlled into the chamber 1 from the radiation portion 125 of each electromagnetic wave radiation mechanism 2 (step S4). Thereby, the microwaves with the controlled phases interfere with each other in the space V, and the microwaves can be converged at a predetermined position of the dielectric window 5. Thereby, local plasma is generated in the space U between the dielectric window 5 and the mounting table 3, and the wafer W is subjected to predetermined plasma processing by the generated local plasma.

Next, the controller 8 determines whether or not to end the plasma processing on the wafer W (step S5). The control device 8 controls the phases of the microwaves output from the 7 electromagnetic wave radiation mechanisms 2 over time until it is determined from the recipe (recipe) that the end time of the plasma processing on the wafer W has come (step S4). When it is determined from the recipe that the end time of the plasma processing for the wafer W has reached, the control device 8 ends the present processing. When the process is finished, the output of the microwave is stopped, and the supply of the gas is stopped.

[ simulation results of phase control ]

Fig. 6B and 6C show an example of simulation results of the electric field distribution in the dielectric window 5 according to one embodiment when the control device 8 controls the phase of the microwave output from the 19 electromagnetic wave radiation mechanisms 2 using the phase shifters 7 as shown in fig. 6A.

As a condition for this simulation, it is set that microwaves of the same power are radiated from the 19 electromagnetic wave radiation mechanisms 2. The electric field intensity of the microwaves shown in fig. 6A, 6B, and 6C indicates a state where the electric field intensity is higher in a dark portion.

As a result of controlling the phases δ (x) of the microwaves so as to mutually strengthen each other at the focal position C1 of the dielectric window 5, the electric field of the microwaves is intensified at the focal portion Ar centered on the focal position C1, as shown in fig. 6B.

Then, the phase of each microwave radiated from the 19 electromagnetic wave radiation mechanisms 2 is controlled by the phase shifter 7 so that the converging portion Ar of the electric field intensity of the microwave is moved toward the center in the radial direction. Fig. 6C shows an example of a simulation result of the electric field distribution in the dielectric window 5. This makes it possible to move the portion of the microwave having the strong electric field to the convergence Ar centered on the focal position C2. This simulation confirmed that the convergence control can be freely performed by the phase control.

As described above, according to the plasma processing apparatus 10 of the present embodiment, the electric field distribution in the dielectric window 5 can be changed without depending on the arrangement of the plurality of electromagnetic wave radiation mechanisms 2. This enables free convergence control by phase control, and thus free control of the plasma distribution.

The plasma processing apparatus 10 according to the present invention has been described by taking a plasma processing apparatus that radiates microwaves as an example, but the present invention is not limited thereto. The plurality of electromagnetic wave radiation means 2 included in the plasma processing apparatus 10 according to the present invention may radiate electromagnetic waves having a frequency of 100MHz or higher, such as UHF, without being limited to the radiation of microwaves. The electromagnetic wave radiation means 2 more preferably radiates electromagnetic waves having a frequency in the range of 1GHz to 3 GHz. The higher the frequency, the higher the speed of phase control.

In the above embodiment, the space V above the dielectric window 5 is an air space, but the present invention is not limited thereto. For example, the space V above the dielectric window 5 may be filled with a dielectric of the same material as the dielectric window 5 or a different material. By filling the space V with the dielectric, the wavelength of the microwave propagating through the dielectric can be shortened, and therefore the plasma processing apparatus 10 can be downsized.

In the above embodiment, the space V above the dielectric window 5 is made to be an air space, but the space V may be a vacuum space. However, when the space V is a vacuum space, the phase control is performed in the vacuum space, and there is a possibility that plasma is generated in the space V. For the above reason, the space V above the dielectric window 5 is preferably an air space. Further, by making the distance D between the radiation section 125 and the dielectric window 5 larger than 1/4 of the wavelength λ of the microwave, the microwave can be sufficiently converged on the dielectric window 5.

The plasma processing method and the plasma processing apparatus according to one embodiment of the present disclosure should be considered in all respects as illustrative and not restrictive. The above-described embodiment can be modified and improved in various ways without departing from the scope of the appended claims and the gist thereof. The matters described in the above embodiments may be combined in other configurations within the scope of no inconsistency.

The present application claims priority based on the basic application No. 2019-.

Description of the reference numerals

1 chamber, 2 electromagnetic wave radiation mechanisms, 3 stage, 5 dielectric windows, 6 microwave output units, 7 phase shifters, 8 control units, 9 top plates, 10 plasma processing units, 11 monopole antennas, 121 inner conductors, 122 outer conductors, 124 notch portions, and 125 radiation units.