Treatment method and plasma treatment device

Abstract

The present invention provides a processing method and a plasma processing device, which can maintain the plasma electron density and reduce the plasma electron temperature. The processing method using plasma in a processing container for processing a substrate comprises: a step of supplying gas into the processing container; and a step of intermittently supplying the power of microwaves output from a plurality of microwave introduction components into the processing container, wherein the step of intermittently supplying the power of microwaves periodically turns off the power supply of all the microwaves of the plurality of microwave introduction components for a given time.

Description

Technical Field

[0001] The present invention relates to a processing method and a plasma processing device. Background Art

[0002] Patent Document 1 discloses a technique for plasma cleaning using microwaves. In plasma cleaning, cleaning is performed by chemical action of radicals and physical action of ions in plasma.

[0003] There is a tendency that the energy of the electromagnetic wave concentrates near the radiation port of the electromagnetic wave, and the plasma electron temperature becomes high. As the plasma electron temperature rises, damage due to ion collision occurs near the radiation port of the electromagnetic wave.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-157627 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] The present invention provides a processing method and a plasma processing device which can maintain the plasma electron density and reduce the plasma electron temperature.

[0009] Technical solutions for solving technical problems

[0010] According to one embodiment of the present invention, there is provided a processing method using plasma in a processing container for processing a substrate, which includes: a step of supplying gas into the above-mentioned processing container; and a step of intermittently supplying the power of microwaves output from multiple microwave introduction components into the above-mentioned processing container, wherein the step of intermittently supplying the power of microwaves periodically turns off the power supply of all microwaves of the multiple microwave introduction components for a given time.

[0011] Effects of the Invention

[0012] According to one aspect, the plasma electron density can be maintained and the plasma electron temperature can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic cross-sectional view showing an example of a plasma processing apparatus according to an embodiment.

[0014] Figure 2 Yes means Figure 1 An explanatory diagram of the structure of the control unit shown.

[0015] Figure 3 Yes means Figure 1 An explanatory diagram of the structure of the microwave introduction component shown.

[0016] Figure 4 Yes means Figure 3 A cross-sectional view of the microwave introduction mechanism shown.

[0017] Figure 5 Yes means Figure 4 A three-dimensional view of the antenna portion of the microwave introduction mechanism shown.

[0018] Figure 6 Yes means Figure 4 A plan view of the planar antenna of the microwave introduction mechanism shown.

[0019] Figure 7 yes Figure 1 A bottom view of the top wall of the processing vessel is shown.

[0020] Figure 8 is a pulse plasma T in the cleaning process according to one embodiment. e and N e A diagram showing an example of the evaluation results of .

[0021] Fig. 9 This is a diagram showing an example of turning on and off the power of microwaves output from a plurality of microwave introduction modules according to one embodiment.

[0022] Fig.10 This is a diagram showing an example of a group synchronized with the power of microwaves output from a plurality of microwave introduction modules according to one embodiment.

[0023] Fig.11 This is a diagram showing an example of turning on and off the power from a plurality of microwave introduction modules according to one embodiment.

[0024] Fig.12 This is a diagram showing another example of turning on and off the power from a plurality of microwave introduction modules according to one embodiment.

[0025] Fig.13 This is a flowchart showing an example of a processing method according to one embodiment.

[0026] Fig.14 This is a flowchart showing an example of a cleaning method using a plurality of microwave introduction modules according to one embodiment.

[0027] Description of Reference Numerals

[0028] 1……Plasma treatment device

[0029] 2…Handling containers

[0030] 3... Gas supply mechanism

[0031] 4...Exhaust system

[0032] 5. Microwave introduction component

[0033] 8……Control Department

[0034] 11...Top wall

[0035] 16, 17... Gas inlet pipe

[0036] 16a, 17a... Gas supply holes

[0037] 21……Putting platform

[0038] W...substrate. DETAILED DESCRIPTION

[0039] Hereinafter, the mode for implementing the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same reference numerals are attached to the same components, and overlapping descriptions may be omitted.

[0040] [Plasma processing device]

[0041] First, refer to Figure 1 and Figure 2 , a schematic structure of a plasma processing apparatus 1 according to an embodiment is described. Figure 1 It is a schematic cross-sectional view showing an example of a plasma processing apparatus 1 according to an embodiment. Figure 2 Yes means Figure 1 The plasma processing apparatus 1 of the present embodiment is an apparatus for performing predetermined processing such as film forming processing, diffusion processing, etching processing, ashing processing, etc. on a substrate W such as a semiconductor wafer for manufacturing a semiconductor device, in accordance with a plurality of continuous operations.

[0042] The plasma processing apparatus 1 includes a processing container 2, a mounting table 21, a gas supply mechanism 3, an exhaust device 4, a microwave introduction assembly 5, and a control unit 8. The processing container 2 accommodates a substrate W as a processing object, and processes the substrate W using plasma inside. The mounting table 21 is arranged inside the processing container 2, and has a mounting surface 21a for mounting the substrate W. The gas supply mechanism 3 supplies gas into the processing container 2. The exhaust device 4 performs decompression exhaust in the processing container 2. The microwave introduction assembly 5 introduces microwaves for generating plasma into the processing container 2. The control unit 8 controls each part of the plasma processing apparatus 1.

[0043] The processing container 2 has, for example, a substantially cylindrical shape. The processing container 2 is formed of, for example, a metal material such as aluminum and its alloy. The microwave introduction assembly 5 is disposed at the upper portion of the processing container 2, and introduces electromagnetic waves (microwaves in this embodiment) into the processing container 2, functioning as a plasma generating mechanism for generating plasma.

[0044] The processing container 2 has a plate-shaped top wall 11, a bottom wall 13, and a side wall 12 connecting the top wall 11 and the bottom wall 13. The top wall 11 has a plurality of openings. The side wall 12 has a feed-in and feed-out port 12a. The feed-in and feed-out port 12a is used to carry out the feed-in and feed-out of the substrate W between the processing container 2 and a conveying chamber (not shown) adjacent to the processing container 2. A gate valve G is arranged between the processing container 2 and the conveying chamber (not shown). The gate valve G has the function of opening and closing the feed-in and feed-out port 12a. The gate valve G hermetically seals the processing container 2 in a closed state, and can transfer the substrate W between the processing container 2 and the conveying chamber (not shown) in an open state.

[0045] The bottom wall 13 has a plurality of ( Figure 1 The plasma processing apparatus 1 further includes an exhaust port 13a (two in the example). The plasma processing apparatus 1 further includes an exhaust pipe 14 connecting the exhaust port 13a to the exhaust device 4. The exhaust device 4 includes an APC valve and a high-speed vacuum pump capable of decompressing the internal space of the processing container 2 to a predetermined vacuum degree at a high speed. Such a high-speed vacuum pump includes, for example, a turbomolecular pump. By enabling the high-speed vacuum pump function of the exhaust device 4, the internal space of the processing container 2 is decompressed to a predetermined vacuum degree, for example, 0.133 Pa.

[0046] The plasma processing apparatus 1 further includes a support member 22 for supporting a mounting table 21 in the processing container 2, and an insulating member 23 provided between the support member 22 and the bottom wall 13. The mounting table 21 is a member for horizontally mounting the substrate W. The support member 22 has a cylindrical shape extending from the center of the bottom wall 13 toward the internal space of the processing container 2. The mounting table 21 and the support member 22 are formed of, for example, aluminum having an anodized surface.

[0047] The plasma processing apparatus 1 further includes a high-frequency bias power supply 25 for supplying high-frequency electric power to the mounting table 21, and a matcher 24 provided between the mounting table 21 and the high-frequency bias power supply 25. The high-frequency bias power supply 25 supplies high-frequency electric power to the mounting table 21 to attract ions to the substrate W. The matcher 24 has a circuit for matching the output impedance of the high-frequency bias power supply 25 with the impedance of the carrier side (mounting table 21 side).

[0048] The plasma processing apparatus 1 may further include a temperature control mechanism (not shown) for heating or cooling the mounting table 21. The temperature control mechanism controls the temperature of the substrate W within a range of 25°C (room temperature) to 900°C, for example.

[0049] The plasma processing device 1 also has a plurality of gas introduction pipes 16 and a plurality of gas introduction pipes 17. The plurality of gas introduction pipes 16 are arranged on the top wall 11, and the first gas is supplied from the gas supply hole 16a formed on the lower surface thereof. The plurality of gas introduction pipes 17 are also arranged on the top wall 11, and the second gas is supplied from the gas supply hole 17a formed on the lower surface thereof. The plurality of gas introduction pipes 16 and the gas introduction pipes 17 can extend from the top wall 11 and / or the side wall 12. The openings of the gas introduction pipes 16 and the gas introduction pipes 17 are formed into a concave structure that is expanded from the fine holes of the gas supply holes 16a and the gas supply holes 17a and opens in the processing space. Thus, by expanding the openings of the gas supply holes 16a and the gas supply holes 17a, the concentration of electromagnetic wave energy can be reduced and abnormal discharge can be prevented.

[0050] The gas supply source 31 can be used as a gas supply source for rare gas for plasma generation, or a gas used in oxidation treatment, nitridation treatment, film formation treatment, etching treatment, and ashing treatment. For example, in the cleaning process, a fluorine-containing gas such as NF3 gas can be supplied from the gas introduction pipe 16, and a rare gas such as Ar gas and He gas can be supplied from the gas introduction pipe 17. In order to stabilize the plasma, the rare gas is added to the fluorine-containing gas.

[0051] The gas supply mechanism 3 includes: a gas supply device 3a including a gas supply source 31; a pipe 32a connecting the gas supply source 31 and the plurality of gas introduction pipes 16; and a pipe 32b connecting the gas supply source 31 and the plurality of gas introduction pipes 17. Figure 1 In the figure, one gas supply source 31 is shown, but the gas supply device 3a may include a plurality of gas supply sources depending on the type of gas used.

[0052] The gas supply device 3a further includes a mass flow controller and an on-off valve (not shown) provided in the middle of the pipes 32a and 32b. The types of gases supplied into the processing container 2 and the flow rates of the gases are controlled by the mass flow controller and the on-off valve.

[0053] Each component of the plasma processing device 1 is connected to a control unit 8 and controlled by the control unit 8. The control unit 8 is typically a computer. Figure 2 In the illustrated example, the control unit 8 includes a process controller 81 having a CPU, a user interface 82 connected to the process controller 81 , and a storage unit 83 .

[0054] The process controller 81 is a control mechanism that controls the components related to the processing conditions such as temperature, pressure, gas flow rate, high-frequency electric power for bias application, and microwave output in the plasma processing device 1. Examples of the components include the high-frequency bias power supply 25, the gas supply device 3a, the exhaust device 4, and the microwave introduction unit 5.

[0055] The user interface 82 includes a keyboard and a touch panel for a process manager to input commands for managing the plasma processing apparatus 1 , a display for visually displaying the operating status of the plasma processing apparatus 1 , and the like.

[0056] The storage unit 83 stores control programs and recipes for realizing various processes performed in the plasma processing apparatus 1 under the control of the process controller 81, and records process condition data, etc. The process controller 81 calls out and executes any control program and recipe from the storage unit 83 as required based on instructions from the user interface 82, etc. Thus, the desired process is performed in the processing container 2 of the plasma processing apparatus 1 under the control of the process controller 81.

[0057] The control program and scheme described above can be used in a state where they are stored in a computer-readable storage medium such as a flash memory, a DVD, or a Blu-ray disc. In addition, the scheme described above can also be transmitted from another device via a dedicated line in real time and used online.

[0058] Below, refer to Figure 1 to Figure 6 , describing the structure of the microwave introduction component 5. Figure 3 Yes means Figure 1 1 is an explanatory diagram of the structure of the microwave introduction assembly 5 shown. Figure 4 Yes means Figure 3 A cross-sectional view of the microwave introduction mechanism 63 is shown. Figure 5 Yes means Figure 4 A perspective view of the antenna portion of the microwave introduction mechanism 63 is shown. Figure 6 Yes means Figure 4 A plan view of the planar antenna of the microwave introduction mechanism 63 is shown.

[0059] The microwave introduction assembly 5 is disposed on the upper portion of the processing container 2 to introduce electromagnetic waves (microwaves) into the processing container 2. Figure 1As shown, the microwave introduction assembly 5 has a top wall 11 as a conductive member, a microwave output part 50, and an antenna unit 60. The top wall 11 is arranged on the upper part of the processing container 2 and has a plurality of openings. The microwave output part 50 generates microwaves and distributes the microwaves to a plurality of paths for output. The antenna unit 60 introduces the microwaves output from the microwave output part 50 into the processing container 2. In this embodiment, the top wall 11 of the processing container 2 also serves as a conductive member of the microwave introduction assembly 5.

[0060] like Figure 3 As shown, the microwave output unit 50 includes: a power supply unit 51; a microwave oscillator 52; an amplifier 53 that amplifies the microwave oscillator 52; and a distributor 54 that distributes the microwave amplified by the amplifier 53 to a plurality of paths. The microwave oscillator 52 oscillates the microwave at a predetermined frequency (for example, 2.45 GHz). In addition, the frequency of the microwave is not limited to 2.45 GHz, and may also be 8.35 GHz, 5.8 GHz, 1.98 GHz, etc. In addition, such a microwave output unit 50 can also be applied to the case where the frequency of the microwave is in the range of 800 MHz to 1 GHz, such as 860 MHz. The distributor 54 matches the impedance of the input side and the output side and distributes the microwave.

[0061] The antenna unit 60 includes a plurality of antenna modules 61. The plurality of antenna modules 61 respectively introduce the microwaves distributed by the distributor 54 into the processing container 2. In the present embodiment, the structures of the plurality of antenna modules 61 are all the same. Each antenna module 61 has: an amplifier section 62 that mainly amplifies the distributed microwaves and outputs them; and a microwave introduction mechanism 63 that introduces the microwaves output from the amplifier section 62 into the processing container 2. The antenna module 61 is arranged on the top wall 11 of the processing container 2, and corresponds to a microwave introduction component (electromagnetic wave introduction module) that introduces the microwaves into the processing container 2.

[0062] The amplifier unit 62 includes a phase shifter 62A, a variable gain amplifier 62B, a main amplifier 62C, and an isolator 62D. The phase shifter 62A changes the phase of the microwave. The variable gain amplifier 62B adjusts the electric power level of the microwave input to the main amplifier 62C. The main amplifier 62C is configured as a solid-state amplifier. The isolator 62D separates the reflected microwaves that are reflected by the antenna unit of the microwave introduction mechanism 63 and go to the main amplifier 62C.

[0063] The phase shifter 62A changes the phase of the microwaves to change the radiation characteristics of the microwaves. The phase shifter 62A is used, for example, to control the directivity of the microwaves to change the distribution of the plasma by adjusting the phase of the microwaves for each antenna module 61. In addition, when such an adjustment of the radiation characteristics is not performed, the phase shifter 62A may not be provided.

[0064] The variable gain amplifier 62B is used to adjust the dispersion and plasma intensity of each antenna module 61. For example, by changing the variable gain amplifier 62B for each antenna module 61, the distribution of the entire plasma in the processing chamber 2 can be adjusted.

[0065] The main amplifier 62C includes, for example, an input matching circuit (not shown), a semiconductor amplifying element, an output matching circuit, and a high Q resonance circuit. As the semiconductor amplifying element, for example, GaAsHEMT, GaNHEMT, or LD (Laterally Diffused)-MOS capable of E-class operation can be used.

[0066] The isolator 62D has a circulator and an equivalent load (dummy load) (coaxial terminator). The circulator guides the reflected microwave reflected by the antenna part of the microwave introduction mechanism 63 to the equivalent load. The equivalent load converts the reflected microwave guided by the circulator into heat. In addition, as described above, in the present embodiment, a plurality of antenna modules 61 are provided, and a plurality of microwaves introduced into the processing container 2 by the microwave introduction mechanisms 63 of the plurality of antenna modules 61 are synthesized in the processing container 2. Therefore, each isolator 62D can be a small isolator, and the isolator 62D can be provided adjacent to the main amplifier 62C.

[0067] like Figure 1 As shown, a plurality of microwave introduction mechanisms 63 are provided on the top wall 11. Figure 4 As shown in FIG. 1 , the microwave introduction mechanism 63 includes a tuner 64 for impedance matching and an antenna 65 for radiating the amplified microwaves into the processing container 2. The microwave introduction mechanism 63 is made of a metal material and includes: Figure 4 The main body container 66 is a cylindrical main body container 66 extending in the vertical direction; and the inner conductor 67 extending in the main body container 66 in the same direction as the direction in which the main body container 66 extends. The main body container 66 and the inner conductor 67 constitute a coaxial tube. The main body container 66 constitutes the outer conductor of the coaxial tube. The inner conductor 67 has a rod-like or cylindrical shape. The space between the inner circumference of the main body container 66 and the outer circumference of the inner conductor 67 forms a microwave transmission path 68.

[0068] The antenna module 61 further includes a power supply conversion unit (not shown) provided at the root end side (upper end side) of the main body container 66. The power supply conversion unit is connected to the main amplifier 62C via a coaxial cable. The isolator 62D is provided in the middle of the coaxial cable. The antenna unit 65 is provided on the opposite side of the power supply conversion unit in the main body container 66. As described later, the portion of the main body container 66 closer to the root end side than the antenna unit 65 becomes the impedance adjustment range of the tuner 64.

[0069] like Figure 4 and Figure 5 As shown, the antenna unit 65 includes: a planar antenna 71 connected to the lower end of the inner conductor 67; a microwave delay component 72 arranged on the upper surface side of the planar antenna 71; and a microwave transmission plate 73 arranged on the lower surface side of the planar antenna 71. The lower surface of the microwave transmission plate 73 is exposed to the internal space of the processing container 2. The microwave transmission plate 73 is fitted into the opening of the top wall 11, which is a conductive member of the microwave introduction assembly 5, via the main body container 66. The microwave transmission plate 73 corresponds to the microwave transmission window in this embodiment.

[0070] The planar antenna 71 has a disk shape. In addition, the planar antenna 71 has a slot 71a formed so as to penetrate the planar antenna 71. Figure 5 and Figure 6 In the example shown, four slits 71a are provided, and each slit 71a has an arc shape equally divided into four. The number of slits 71a is not limited to four, and may be five or more, or one or more and three or less.

[0071] The microwave delay component 72 is formed of a material having a dielectric constant greater than that of a vacuum. As the material forming the microwave delay component 72, for example, quartz, ceramics, fluorine resins such as polytetrafluoroethylene resin, polyimide resin, etc. can be used. The wavelength of microwaves in a vacuum becomes longer. The microwave delay component 72 has the function of shortening the wavelength of microwaves to adjust plasma. In addition, the phase of the microwaves changes according to the thickness of the microwave delay component 72. Therefore, by adjusting the phase of the microwaves according to the thickness of the microwave delay component 72, it is possible to adjust the position of the antinode of the standing wave of the planar antenna 71. As a result, the reflected wave in the planar antenna 71 can be suppressed, and the radiation energy of the microwaves radiated from the planar antenna 71 can be increased. That is, as a result, the power of the microwaves can be effectively introduced into the processing container 2.

[0072] The microwave transmission plate 73 is formed of a dielectric material. As the dielectric material forming the microwave transmission plate 73, for example, quartz, ceramics, etc. can be used. The microwave transmission plate 73 is formed into a shape that can effectively radiate microwaves in the TE mode. Figure 5 In the example, the microwave transmitting plate 73 has a rectangular parallelepiped shape. In addition, the shape of the microwave transmitting plate 73 is not limited to the rectangular parallelepiped shape, and may be, for example, cylindrical, pentagonal, hexagonal, or octagonal.

[0073] In the microwave introduction mechanism 63 of the above structure, the microwave amplified by the main amplifier 62C reaches the planar antenna 71 through the microwave transmission path 68 between the inner peripheral surface of the main container 66 and the outer peripheral surface of the inner conductor 67. Then, the microwave passes through the microwave transmission plate 73 from the slit 71a of the planar antenna 71 and is radiated into the internal space of the processing container 2.

[0074] The tuner 64 is a slug tuner. Figure 4 As shown, the tuner 64 has two cores 74A and 74B disposed on the base end side (upper end side) of the main body container 66 relative to the antenna unit 65. The tuner 64 further includes an actuator 75 for operating the two cores 74A and 74B and a tuner controller 76 for controlling the actuator 75.

[0075] The iron cores 74A and 74B have a plate-like and annular shape and are arranged between the inner circumference of the main body container 66 and the outer circumference of the inner conductor 67. In addition, the iron cores 74A and 74B are formed of a dielectric material. As a dielectric material forming the iron cores 74A and 74B, for example, high-purity alumina with a relative dielectric constant of 10 can be used. Compared with quartz (relative dielectric constant 3.88) and Teflon (registered trademark) (relative dielectric constant 2.03) used as materials for forming the iron core, high-purity alumina generally has a larger relative dielectric constant, so the thickness of the iron cores 74A and 74B can be reduced. In addition, compared with quartz and Teflon (registered trademark), high-purity alumina has a smaller loss tangent (tanδ) and has the characteristic of being able to reduce the loss of microwaves. High-purity alumina also has the characteristics of small deformation and strong heat resistance. As high-purity alumina, an aluminum sintered body with a purity of 99.9% or more is preferred. Alternatively, single crystal aluminum (sapphire) may be used as high-purity aluminum oxide.

[0076] Tuner 64 moves cores 74A and 74B in the vertical direction via actuator 75 based on a command from tuner controller 76. This adjusts the impedance of tuner 64. For example, tuner controller 76 adjusts the positions of cores 74A and 74B so that the impedance of the terminal portion becomes, for example, 50Ω.

[0077] In this embodiment, the main amplifier 62C, the tuner 64, and the planar antenna 71 are arranged close to each other. In particular, the tuner 64 and the planar antenna 71 constitute a lumped constant circuit and function as a resonator. There is an impedance mismatch in the mounting portion of the planar antenna 71. In this embodiment, the tuner 64 can be used to tune with high precision while including the plasma, and the influence of reflection in the planar antenna 71 can be eliminated. In addition, the tuner 64 can be used to eliminate the impedance mismatch up to the planar antenna 71 with high precision, and the mismatched portion can be made substantially a plasma space. Thus, the tuner 64 can be used to perform high-precision plasma control.

[0078] Below, refer to Figure 7 ,illustrate Figure 1 The bottom surface of the top wall 11 of the processing container 2 is shown. Figure 7 Yes means Figure 1FIG. 1 is a diagram showing an example of the bottom surface of the ceiling wall 11 of the processing container 2. In the following description, the microwave transmitting plate 73 has a cylindrical shape.

[0079] The microwave introduction assembly 5 includes a plurality of microwave transmission plates 73. As described above, the microwave transmission plates 73 correspond to the microwave transmission windows. The plurality of microwave transmission plates 73 are arranged on a virtual plane parallel to the mounting surface 21a of the mounting table 21 in a state of being fitted into the plurality of openings of the top wall 11 as the conductive member of the microwave introduction assembly 5. In addition, the plurality of microwave transmission plates 73 include three microwave transmission plates 73 whose center points have the same or substantially the same distances in the virtual plane. In addition, the substantially equal distances between the center points means that the position of the microwave transmission plate 73 may be slightly deviated from the desired position from the viewpoint of the shape accuracy of the microwave transmission plate 73, the assembly accuracy of the antenna module 61 (microwave introduction mechanism 63), and the like.

[0080] In the present embodiment, the plurality of microwave transmitting plates 73 include seven microwave transmitting plates 73 arranged in a hexagonal closest-packed arrangement. Specifically, the plurality of microwave transmitting plates 73 include seven microwave transmitting plates 73A to 73G. Six of the microwave transmitting plates 73A to 73F are arranged so that their center points coincide with or approximately coincide with the vertices of a regular hexagon. One microwave transmitting plate 73G is arranged so that its center point coincides with or approximately coincides with the center of the regular hexagon. In addition, approximately coinciding with the vertices or the center means that the center point of the microwave transmitting plate 73 may be slightly deviated from the above-mentioned vertex or center from the viewpoint of the shape accuracy of the microwave transmitting plate 73, the assembly accuracy of the antenna module 61 (microwave introduction mechanism 63), and the like.

[0081] like Figure 7 As shown, the microwave transmission plate 73G is arranged at the central part of the top wall 11. The six microwave transmission plates 73A to 73F are arranged outside the central part of the top wall 11 in a manner of surrounding the microwave transmission plate 73G. Therefore, the microwave transmission plate 73G corresponds to the central microwave transmission window, and the microwave transmission plates 73A to 73F correspond to the outer microwave transmission windows. In addition, in this embodiment, the "central part of the top wall 11" refers to the "central part of the planar shape of the top wall 11".

[0082] In the present embodiment, among all the microwave transmission plates 73, the distances between the center points of any three adjacent microwave transmission plates 73 are equal or substantially equal. Six gas introduction pipes 16 are arranged at equal intervals in the circumferential direction between the outer microwave transmission plates 73A to 73F and the central microwave transmission plate 73G. The gas introduction pipes 16 supply the first gas into the processing container 2 from the gas supply holes 16a formed at the front ends thereof. Six gas introduction pipes 17 are arranged in the circumferential direction between the six gas introduction pipes 16. The gas introduction pipe 17 is arranged between the adjacent gas introduction pipes 16. The gas introduction pipe 17 supplies the second gas into the processing container 2 from the gas supply holes 17a formed at the front ends thereof.

[0083] [Evaluation results of cleaning treatment]

[0084] Below, refer to Figure 8 , the evaluation results of the cleaning process performed under the control of the control unit 8 of the plasma processing apparatus 1 are described. Figure 8 is a plasma electron temperature T of the plasma generated in the cleaning process of one embodiment. e and the plasma electron density N e A diagram showing an example of the evaluation results of . Figure 8 The horizontal axis represents time t (ms), and the vertical axis represents the plasma electron density N e and plasma electron temperature T e .

[0085] In the cleaning process of this embodiment, the cleaning gas is supplied from the gas introduction pipe 16 and the gas introduction pipe 17 to the processing container 2. In addition, the power of the microwave from the microwave introduction component 5 is intermittently supplied to the processing container 2. As a result, the cleaning gas is excited to generate plasma. The power of the microwave from the microwave introduction component 5 is controlled, for example, so that it is repeatedly turned on and off with a duty ratio of 50%. That is, the power of the microwave from the microwave introduction component 5 is repeatedly turned on and off with the same time period. Figure 8 The time of "Pulse ON" when the microwave power is turned on and the time of "Pulse OFF" when the microwave power is turned off are set. In addition, the pressure of the processing container 2 is set to 20 Pa, and the power of the microwave is set to 100W. Figure 8 The plasma electron density N is measured from the bottom of the top wall 11 to 90 mm below the plasma generated under this condition. e and plasma electron temperature T e An example of the results obtained.

[0086] Plasma is generated from the cleaning gas according to the time of "pulse on" and the power of the microwave. The interior of the processing container 2 is cleaned by the chemical action of free radicals (for example, F free radicals) and the physical action of ions (for example, Ar ions) in the generated plasma. As an example, NF3 gas is supplied from the gas inlet pipe 16 as a cleaning gas, and Ar gas is supplied from the gas inlet pipe 17. However, as a cleaning gas, a gas including a fluorine-containing gas and a rare gas can be supplied. At this time, one of the fluorine-containing gas and the rare gas can also be supplied from the gas inlet pipe 16, and the other can be supplied from the gas inlet pipe 17.

[0087] like Figure 8 As shown in FIG. 1 , when the microwave power changes periodically from “pulse on” (hereinafter referred to as “on or on state”) to “pulse off” (hereinafter referred to as “off or off state”), the plasma electron temperature Te rises sharply. e It decreases sharply and stabilizes at a low temperature in about 300μs. In addition, when the microwave power changes periodically from on to off, the plasma electron temperature T e Rise momentarily, then fall.

[0088] On the other hand, when the microwave power is switched from on to off, the plasma electron density N e No plasma electron temperature T e When the microwave power is switched from on to off, the plasma electron density N e The maximum value is N e max, until it reaches the maximum value N e The plasma electron density is half of the maximum (=N e max / 2) takes about 1.0ms.

[0089] According to the above, when the off time of the microwave pulse wave is controlled to about 300 μs, the plasma electron density N e And reduce the plasma electron temperature T e , thereby, it is possible to perform a cleaning process in the processing container 2 while reducing damage caused by plasma (especially ions). The off time of the microwave pulse wave is not limited to about 300μs, and can be in the range of 30μs to 500μs. Thus, the plasma electron density N e And reduce the plasma electron temperature T e Reduce the damage caused by ions.

[0090] In the plasma processing apparatus 1 having a plurality of microwave introduction assemblies 5, microwaves are continuously supplied from the plurality of microwave introduction assemblies 5, and plasma cleaning is performed by generating plasma from a cleaning gas using the power of the microwaves. As a result, for example, electromagnetic wave energy is concentrated near the microwave transmission plate 73, which is the radiation port of microwaves with a high frequency of 860 MHz, that is, near the microwave transmission plate 73 on the bottom surface of the top wall 11, and the electron temperature tends to increase. Sometimes, due to the increase in the electron temperature, the self-bias voltage near the microwave transmission plate 73 increases, and ions are accelerated in the sheath, causing damage to the bottom surface of the top wall 11 and the like due to the collision of ions near the microwave transmission plate 73.

[0091] Therefore, in the cleaning process of this embodiment, microwaves are not radiated continuously, but radiated in a pulse wave manner to generate plasma for cleaning. In addition, when radiating microwave pulse waves, multiple microwave pulse waves are radiated synchronously by turning on and off, or multiple microwave pulse waves are radiated asynchronously (for example, randomly), or they are combined and controlled to perform cleaning. When using microwave pulse waves, the plasma electron temperature T can be reduced. e And maintain the plasma electron density N e .

[0092] That is, the processing method of the present embodiment includes the steps of supplying gas into the processing container 2 and the step of intermittently supplying the power of microwaves output from the plurality of microwave introduction components 5 into the processing container 2. Moreover, in the step of intermittently supplying the power of microwaves, the power supply of all microwaves of the plurality of microwave introduction components 5 is periodically turned off for a given time. The "given time" may be, for example, approximately 300μs, preferably within the range of 30μs to 500μs. According to the processing method, the power supply of all microwave introduction components 5 is periodically turned off for a "given time". Thus, Figure 8 As shown, it is possible to maintain the plasma electron density N e And the plasma electron temperature Te is lowered. As described above, in the processing method of this embodiment, the power supply of all the seven microwave introduction units 5 is periodically controlled to be turned off for a predetermined time.

[0093] High-energy electrons and ions are accumulated in the sheath. When the microwave power is switched from on to off or from off to on, the state of the plasma changes. On the other hand, the plasma has the property of maintaining its own state. Therefore, during the above switching, the high-energy electrons in the sheath move so that the plasma maintains its own state. In order to suppress the movement of such energy-releasing electrons and ions, the plasma electron temperature T is generated at the moment when the microwave power is turned on or off. eA sharp rise followed by a fall.

[0094] According to the following formula (1), when the energy E of the ion ion In the high state, the plasma electron temperature T e That is, the energy E of the ions is increased because the energy released by the electrons and ions is suppressed. ion becomes higher, so at the moment when the microwave power is turned on or off, the plasma electron temperature T e rise.

[0095]

[0096] Here, M in the formula (1) is the mass of the molecules of the rare gas (for example, Ar gas) in the gas, and m is the mass of the electron.

[0097] In this regard, in the processing method of this embodiment, microwaves are applied in a pulsed manner so that after the microwave power is turned on or off, the plasma electron density N e When it stops decreasing, turn it on or off again. Figure 8 As the electron density N in the plasma e When the plasma electron density N e is the maximum value (N e max).

[0098] For example, Fig. 9 As shown, the power of the microwaves output from the seven (plural) microwave introduction assemblies 5 can be applied synchronously and intermittently. Here, the pulse waves of the microwaves output from the seven microwave introduction assemblies 5 are turned on and off at the same or substantially the same timing. As described above, by synchronously applying the pulse waves of a plurality of microwaves, the power of all the microwaves is turned off for a given time, thereby reducing the electron temperature T when switching the microwaves on and off. e The given time for all microwaves to be in the off state is, for example, preferably 300 μs, preferably within the range of 30 μs to 500 μs.

[0099] In addition, by applying a plurality of microwave pulse waves asynchronously, it is also possible to suppress the electron temperature T when switching the microwaves on and off. e As an example of a method of asynchronously applying a plurality of microwave pulse waves, it is possible to cite a method of randomly setting the timing of turning on and off the power of the microwaves output from the plurality of microwave introduction components 5 at a time other than a given time. In this case, the given time when all microwaves are turned off is, for example, preferably 300 μs, preferably within a range of 30 μs to 500 μs.

[0100] As described above, in the processing method of this embodiment, the timing of turning on and off the power of the microwaves output from the plurality of microwave introduction components 5 may be synchronized or asynchronous. In the case of synchronization, the timing of turning on and off the pulse waves of the microwaves output from the plurality of microwave introduction components 5 may be consistent, or the timing of turning on and off the pulse waves of at least any one of the microwaves may be staggered.

[0101] However, when the timing of turning on and off the microwave pulse wave is made consistent, the turning on and off of the seven microwave introduction components 5 are switched at the same timing. Therefore, the plasma electron temperature T is lower when switching from on to off or from off to on. e Easier to rise.

[0102] Therefore, it is preferable to stagger the timing of turning on and off at least any one of the pulse waves of the microwaves of the seven microwave introduction modules 5. Figure 10 to Figure 12 , which illustrates the situation where the timing of turning on and off the microwaves of the seven microwave introduction components 5 is staggered. Fig.10 This is a diagram showing an example of a group for synchronizing the powers of microwaves output from a plurality of microwave introduction modules according to one embodiment. Fig.11 This is a diagram showing an example of turning on and off the power from a plurality of microwave introduction modules according to one embodiment. Fig.12 This is a diagram showing another example of turning on and off the power from a plurality of microwave introduction modules according to one embodiment.

[0103] For example, Fig.10 As shown, the group of microwaves output from the microwave transmitting plates 73B and 73E in the housing 1 is referred to as the first group (1G). The group of microwaves output from the microwave transmitting plates 73C and 73F is referred to as the second group (2G). The group of microwaves output from the microwave transmitting plates 73A and 73D is referred to as the third group (3G).

[0104] In this case, if Fig.11 As shown, all microwaves output from the microwave transmitting plate 73 are turned on after the NF3 gas and the Ar gas are supplied. Fig.11 The microwave of "1st G" is first turned on after the NF3 gas and the Ar gas are supplied, and is repeatedly turned on and off at a duty ratio of 50%. Fig.11 The "2nd G" microwave becomes the on state after Ta time has passed since the 1st G microwave became the on state, and repeatedly turns on and off at a duty ratio of 50%. Fig.11 The "3rd G" microwave becomes turned on after Tb (Tb>Ta) time has passed since the 1st G microwave became turned on, and repeatedly turns on and off with a duty ratio of 50%.

[0105] By this control, the switching timing of the microwaves belonging to each group from on to off or from off to on is staggered, thereby suppressing the plasma electron temperature T e The rise in ion density can reduce the damage caused by ion impact. When the switching timing of microwaves from on to off or from off to on is staggered as described above, a "given time" for all microwaves to be off is also ensured. Fig.11 In the case of the example, the time T2 when all microwaves are turned off is a given time relative to the time T1 when at least any one microwave is turned on. The time T2 is preferably in the range of 30 μs to 500 μs, and the optimal value in this example is 300 μs.

[0106] exist Fig.10 In the housing 2, the group of microwaves output from the microwave transmission plates 73B, 73C, 73E, 73F, and 73G is defined as the first group. The group of microwaves output from the microwave transmission plates 73A, 73C, 73D, 73F, and 73G is defined as the second group. In this case, Fig.11 The timing shown (where 3G does not exist) controls each group.

[0107] exist Fig.10 In the housing 3, the group of microwaves output from the microwave transmitting plate 73G may be the first group, and the group of microwaves output from the microwave transmitting plates 73B and 73E may be the second group. Furthermore, the group of microwaves output from the microwave transmitting plates 73C and 73F may be the third group, and the group of microwaves output from the microwave transmitting plates 73A and 73D may be the fourth group.

[0108] In this case, Fig.12 The microwave of "1st G" is first turned on after the NF3 gas and the Ar gas are supplied, and is repeatedly turned on and off at a duty ratio of 50%. Fig.12 The "2nd G" microwave becomes turned on after Ta time has passed since the 1st G microwave became turned on, and repeatedly turns on and off at a duty ratio of 50%. Fig.12 The "3rd G" microwave becomes turned on after Tb (Tb>Ta) time has passed since the 1st G microwave became turned on, and repeatedly turns on and off with a duty cycle of 50%. Fig.12 The "4th G" microwave becomes turned on after Tc (Tc>Tb>Ta) time has passed since the 1st G microwave became turned on, and repeatedly turns on and off with a duty cycle of 50%.

[0109] By this control, the switching timing of the microwave from on to off or from off to on is staggered, thereby suppressing the plasma electron temperature T eThe rise in ion density can reduce the damage inside the processing container 2 caused by the impact of ions. When the switching timing of the microwave from on to off or from off to on is staggered as described above, the "given time" for all microwaves to be in the off state is also ensured. Fig.12 In the case of the example, the time T4 when all microwaves are turned off is a given time relative to the time T3 when at least any one microwave is turned on. The time T4 is preferably in the range of 30 μs to 500 μs, and the optimal value in this example is 300 μs.

[0110] It is also possible to randomly set the timing of turning on and off the pulse waves of microwaves output from multiple microwave introduction components at times other than a given time. In this case, it is also ensured that the "given time" for all microwaves to be in the off state is in the range of 30μs to 500μs. In addition, in the above example, the duty cycle of the microwave pulse wave is set to 50%, but it is not limited to this, and it can also be 10% to 50%. In addition, in the above example, the first connection after a given time is fixed to the 1st G, but after a given time, the first group to be connected can be changed each time it is turned on in the form of 1st G→2nd G→3rd G→1st G→2nd G→3rd G. In this way, the plasma electron temperature T e The rising parts are dispersed, which can relatively reduce the damage to each part.

[0111] [Handling method]

[0112] Below, refer to Fig.13 and Fig.14 , an example of a processing method according to an embodiment is described. Fig.13 This is a flowchart showing an example of a processing method sw according to one embodiment. Fig.14 This is a flowchart showing an example of a cleaning method using a plurality of microwave introduction modules 5 according to one embodiment. Fig.14 The cleaning method shown is Fig.13 is called out in step S7. Fig.13 The treatment method and Fig.14 The cleaning treatment method is controlled by the control unit 8.

[0113] exist Fig.13 At the beginning of the processing method sw, the control unit 8 sends the substrate W into the processing container 2 and holds it on the mounting table 21 to prepare the substrate W (step S1). Next, the control unit 8 supplies a gas for processing the substrate W, introduces microwave power to generate plasma from the gas, and uses the generated plasma to perform a predetermined process such as film forming process, diffusion process, etching process, ashing process, etc. on the substrate W. Thereafter, the control unit 8 sends out the processed substrate W (step S3).

[0114] Next, the control unit 8 determines whether a predetermined number of substrates have been processed (step S5). When the control unit 8 determines that the predetermined number of substrates have not been processed, it returns to step S1, prepares the next unprocessed substrate W, and performs plasma processing on the next substrate W (steps S1 and S3). In step S5, when the control unit 8 determines that the predetermined number of substrates have been processed, it proceeds to step S7 to perform cleaning processing and terminates the present processing. In addition, when the present processing is terminated, the microwave output is stopped and the gas supply is stopped.

[0115] Reference Fig.14 , which explains the details of the cleaning process performed in step S7. The control unit 8 inputs a first group of microwave pulse waves predetermined in the seven microwave introduction components 5 (step S11). For example, Fig.11 The 1G microwave is turned on and periodically switches between on and off states.

[0116] Next, the control unit 8 inputs a second group of microwave pulse waves predetermined in the seven microwave introduction modules 5 (step S13). Fig.11 After the Ta time, the 2G microwave becomes on and periodically repeats the on and off states.

[0117] Next, the control unit 8 inputs a third group of microwave pulse waves predetermined in advance into the seven microwave introduction modules 5 (step S15). Fig.11 After Tb time, the 3G microwave becomes on, and the on and off states are repeated periodically. Next, the control unit 8 determines whether it is time to end cleaning (step S17). When the control unit 8 determines that it is time to end cleaning, the present process is terminated.

[0118] According to the plasma processing method, the power supply of all the microwave introduction components 5 is periodically turned off for a given time. This can maintain the plasma electron density N e And more effectively reduce the plasma electron temperature T e , reducing damage caused by ions.

[0119] The plasma processing device of one embodiment disclosed in the present invention is illustrative in all aspects and should not be considered as restrictive. The above-mentioned embodiment can be deformed and improved in various ways without departing from the attached claims and their main purpose. The contents recorded in the above-mentioned multiple embodiments can also be added with other structures within the scope of non-contradiction, and can be combined within the scope of non-contradiction.

[0120] For example, the processing method of this embodiment is not limited to cleaning processing, and can also be used as a processing method for film formation processing, etching processing, etc.

Claims

1. A method for processing a substrate using plasma in a processing container, characterized in that: include: The step of supplying gas into the processing container; and The step of intermittently supplying the power of microwaves output from a plurality of microwave introduction assemblies into the processing container, In the step of intermittently supplying microwave power, the timing of turning on and off the power of at least any one of the microwaves output from the plurality of microwave introduction assemblies is staggered so as to satisfy both of the following (A) and (B): (A) when one group of microwaves among the powers of the microwaves outputted from the plurality of microwave introduction modules is in an on state, turning another group of microwaves from an off state to an on state; (B) The power supply of all the microwaves to the plurality of microwave introduction modules is periodically turned off for a predetermined period of time.

2. The processing method according to claim 1, characterized in that: The step of intermittently supplying microwave power includes randomly setting the timing of turning on and off the power of the microwaves output from the plurality of microwave introduction modules at a time other than the given time.

3. The processing method according to claim 1 or 2, characterized in that: The step of intermittently supplying microwave power synchronizes the timing of turning on and off the power of the microwaves output from the plurality of microwave introduction modules.

4. The processing method according to claim 1 or 2, characterized in that: The treatment method is a cleaning treatment, The gas is a clean gas.

5. The processing method according to claim 4, characterized in that: The cleaning gas includes a fluorine-containing gas and a rare gas.

6. The processing method according to claim 1 or 2, characterized in that: The given time is in the range of 30 μs to 500 μs.

7. A plasma processing device comprising a processing container for processing a substrate and a control unit, wherein the processing is performed using plasma in the processing container, wherein: The control unit controls: The step of supplying a gas into the processing container; and The step of intermittently supplying the power of microwaves output from a plurality of microwave introduction assemblies into the processing container, In the step of intermittently supplying microwave power, the timing of turning on and off at least any one of the microwave powers output from the plurality of microwave introduction assemblies is staggered so as to satisfy both of the following (A) and (B): (A) when one of the microwave groups among the microwave powers output from the plurality of microwave introduction modules is in an on state, turning another microwave group from an off state to an on state; (B) Periodically controlling the supply of power of all the microwaves of the plurality of microwave introduction modules to be turned off for a predetermined period of time.

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