Plasma processing method and plasma processing device

Abstract

The present invention provides a plasma processing method and a plasma processing device, which can determine the state of the inner wall of the plasma processing device with high accuracy. The plasma processing method using a detector for measuring the plasma emission intensity in the plasma processing device includes the following steps: using the detector to detect a first plasma emission intensity measured using light having a first optical axis, the first optical axis being an optical axis that reaches the inner wall of the plasma processing device after passing through a plasma generation region; using the detector to detect a second plasma emission intensity measured using light having a second optical axis, the second optical axis being an optical axis that reaches the inner wall of the plasma processing device without passing through the plasma generation region; and determining the state of the inner wall of the plasma processing device based on the difference or ratio between the detected first plasma emission intensity and the second plasma emission intensity.

Description

Technical Field

[0001] The present disclosure relates to a plasma processing method and a plasma processing apparatus. Background Art

[0002] A dry etching device is known that detects the endpoint of etching based on changes in the luminous intensity of plasma. For example, Patent Document 1 proposes: a first detector for measuring the luminous intensity of plasma near a semiconductor substrate and a second detector for measuring the luminous intensity of plasma near an etched material disposed on a first electrode are provided, the luminous intensity measured by the first detector and the luminous intensity measured by the second detector are calculated, and the endpoint of etching is detected based on changes in the calculation result.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 9-55367 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In OES (optical emission spectroscopy), the state of plasma can be detected by measuring the emission intensity of plasma. Plasma is affected by the state of the inner wall of the plasma processing device. Therefore, it is important to control the state of the inner wall of the plasma processing device.

[0008] The present disclosure provides a plasma processing method and a plasma processing apparatus capable of determining the state of an inner wall of a plasma processing apparatus with high accuracy.

[0009] Solutions for solving problems

[0010] According to one embodiment of the present disclosure, there is provided a plasma processing method using a detector for measuring plasma luminescence intensity in a plasma processing device, the plasma processing method comprising the following steps: using the detector to detect a first plasma luminescence intensity measured using light having a first optical axis, the first optical axis being an optical axis that passes through a plasma generation region and reaches an inner wall of the plasma processing device; using the detector to detect a second plasma luminescence intensity measured using light having a second optical axis, the second optical axis being an optical axis that reaches the inner wall of the plasma processing device without passing through the plasma generation region; and determining a state of the inner wall of the plasma processing device based on a difference or ratio between the detected first plasma luminescence intensity and the second plasma luminescence intensity.

[0011] Effects of the Invention

[0012] According to one aspect, the state of the inner wall of the plasma processing apparatus can be determined with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0014] Figure 2 This is a diagram showing an example of a detector according to an embodiment.

[0015] Figure 3 This is a diagram showing an example of detection results according to one embodiment.

[0016] Figure 4 It is a diagram showing the difference in light emission intensity (state of the wall) according to one embodiment.

[0017] Figure 5 1 is a flowchart showing a process of measuring plasma emission intensity according to one embodiment.

[0018] Figure 6 1 is a flowchart showing an aging process according to one embodiment.

[0019] Figure 7 It is a diagram for explaining the start and end of adjustment according to one embodiment.

[0020] Figure 8 1 is a flowchart showing a dry cleaning process according to one embodiment.

[0021] Fig. 9 This is a flowchart showing a dry cleaning process according to Modification 1 of one embodiment.

[0022] Fig.10 This is a diagram showing an example of a detector according to an embodiment.

[0023] Fig.11 This is a flowchart showing an aging process according to Modification 2 of one embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, the mode for implementing the present disclosure will be described with reference to the drawings. In each of the drawings, the same components are denoted by the same reference numerals, and duplicate descriptions may be omitted.

[0025] [Plasma processing device]

[0026] First, refer to Figure 1A plasma processing apparatus 10 for executing a plasma processing method according to an embodiment will be described. Figure 1 (a) and (b) are schematic cross-sectional views showing an example of a plasma processing apparatus 10 according to one embodiment, and are parallel plate capacitively coupled plasma (CCP: Capacitively Coupled Plasma) processing apparatuses.

[0027] First of all, Figure 1 The structure of the plasma processing device 10 shown in (a) is described. The plasma processing device 10 includes a processing container 11 and a mounting table 12 arranged inside the processing container 11. The processing container 11 is, for example, a cylindrical container made of aluminum whose surface has been anodized (anodized), and is grounded. The mounting table 12 includes a base 16 and an electrostatic chuck 13 arranged on the base 16. The mounting table 12 is arranged at the bottom of the processing container 11 via a holding portion 14 of an insulating member.

[0028] The base 16 is made of aluminum or the like. The electrostatic chuck 13 is made of a dielectric such as aluminum oxide (Al2O3) and has a mechanism for holding the wafer W by electrostatic adsorption. The wafer W is placed in the center of the electrostatic chuck 13, and an annular edge ring 15 (also called a focus ring) surrounding the wafer W is placed on the periphery.

[0029] An annular exhaust path 23 is formed between the side wall of the processing container 11 and the side wall of the mounting table 12, and the exhaust path 23 is connected to the exhaust device 22 via the exhaust port 24. The exhaust device 22 includes a vacuum pump such as a turbomolecular pump and a dry pump. The exhaust device 22 guides the gas in the processing container 11 to the exhaust path 23 and the exhaust port 24 for exhaust. Thus, the processing space in the processing container 11 is depressurized to a predetermined vacuum degree.

[0030] A baffle 27 is provided in the exhaust path 23 for dividing the exhaust space into a processing space and an exhaust space and controlling the flow of gas. The baffle 27 is, for example, an annular member in which a corrosion-resistant film (e.g., yttrium oxide (Y2O3)) is covered on the surface of a base material formed of aluminum, and a plurality of through holes are formed in the baffle 27.

[0031] The stage 12 is connected to a first high frequency power source 17 and a second high frequency power source 18. The first high frequency power source 17 applies, for example, a 60 MHz high frequency power for generating plasma (hereinafter, also referred to as "HF power") to the stage 12. The second high frequency power source 18 applies, for example, a 40 MHz high frequency power for attracting ions (hereinafter, also referred to as "LF power") to the stage 12. Thus, the stage 12 also functions as a lower electrode.

[0032] A shower head 20 is provided on the outer periphery of the opening of the top of the processing container 11 via a ring-shaped insulating member 28. HF power is capacitively applied between the mounting table 12 and the shower head 20, and plasma is generated from gas mainly by the HF power.

[0033] Ions in the plasma are attracted to the mounting table 12 by the LF power applied to the mounting table 12 , and the ions collide with the wafer W mounted on the mounting table 12 , so that a predetermined film or the like on the wafer W is efficiently etched.

[0034] The gas supply source 19 supplies gas corresponding to the process conditions of each plasma processing step such as etching step, cleaning step, aging step, etc. The gas enters the shower head 20 through the gas pipe 21, and is introduced into the processing container 11 in a spraying manner through a large number of gas through holes 26 through a gas diffusion chamber 25.

[0035] Figure 1 The plasma processing device 10 shown in (b) has Figure 1 The structure of the plasma processing apparatus 10 shown in (a) is substantially the same as that of the plasma processing apparatus 10, but the configuration of the first high frequency power supply 17 and the structure of the detector 40 described later are different. Figure 1 In the plasma processing apparatus 10 of (b), the first high frequency power source 17 is connected to the shower head 20. The first high frequency power source 17 applies 60 MHz HF power to the shower head 20, for example.

[0036] The control unit 30 includes a CPU, a ROM (Read Only Memory), and a RAM (Random Access Memory). The control unit 30 controls various plasma processing steps and the entire apparatus according to the procedures set in the recipe stored in the RAM.

[0037] When plasma processing is performed in the plasma processing apparatus 10 of the above structure, first, the wafer W is carried into the processing container 11 from the gate valve (not shown) while being held on the transfer arm. The wafer W is placed on the electrostatic chuck 13. The gate valve is closed after the wafer W is carried in. A DC voltage is applied to the electrode (not shown) of the electrostatic chuck 13, so that the wafer W is attracted and held on the electrostatic chuck 13 by the Coulomb force.

[0038] The pressure in the processing container 11 is reduced to a set value by the exhaust device 22, and the interior of the processing container 11 is controlled to be in a vacuum state. The specified gas is introduced into the processing container 11 in a spray form from the shower head 20. HF power and LF power are applied to the mounting table 12. Figure 1 In (a), HF power is applied to the mounting table 12, so the plasma generation area P is near the wafer W. Figure 1 In (b), HF power is applied to the shower head 20 , so the plasma generation area P is near the shower head 20 .

[0039] Plasma is generated from the introduced gas mainly by HF power, and plasma processing such as etching is performed on the wafer W by the action of the plasma. After the plasma processing is completed, the wafer W is held on the transfer arm and carried out to the outside of the processing container 11. The wafer W is continuously processed by repeating this processing.

[0040] While the wafer W is being plasma processed, light emitted inside the processing container 11 enters the detector 40 through a window 41 provided on the side wall.

[0041] The detector 40 has a function of changing the direction of incident light, and detects light having a first optical axis L1 and light having a second optical axis L2. The first optical axis L1 reaches the side wall 11b of the processing container 11 after passing through the plasma generation region P near the wafer W. After the detector 40 is directed toward the top using the function of changing the direction of incident light, the detector 40 detects light having the second optical axis L2. The second optical axis L2 reaches the top wall 11a of the processing container 11 without passing through the plasma generation region P.

[0042] exist Figure 1 In (b), the detector 40 includes a detector 40a and a detector 40b. The detectors 40a and 40b do not have the function of changing the direction of the incident light. The light having the first optical axis L1 and the light having the second optical axis L2 are emitted from the inside of the processing container 11 through different windows 41a and 41b, and are detected by the detectors 40a and 40b, respectively. However, it may also be set as follows Figure 1 Through the same window as shown in (a).

[0043] The detector 40a detects light having a first optical axis L1. The first optical axis L1 passes through the plasma generation region P near the shower head 20 and reaches the side wall 11b of the processing container 11. The detector 40b detects light having a second optical axis L2. The second optical axis L2 reaches the side wall 11b of the processing container 11 without passing through the plasma generation region P.

[0044] The detector 40 uses optical emission spectroscopy (OES) to monitor the state of plasma. In OES, the target element in the sample is evaporated and gasified by discharge plasma, and the wavelength of the emission line (atomic spectrum) inherent to the element is obtained, and the emission intensity is used for quantitative analysis. However, OES is an example of a method for monitoring the state of plasma, and the method used by the detector 40 is not limited to OES as long as the state of plasma can be monitored.

[0045] In addition, if Figure 2 As shown, the detector 40 can change its direction in the up-down direction, the left-right direction, and the oblique direction by the power of the actuator 42. Through the above structure, the detector 40 can move the first optical axis L1 and the second optical axis L2 to be detected. In addition, the detector 40 can be moved to the second optical axis L2', or to other angles and positions. Thus, the plasma luminescence intensity in multiple directions can be measured. Moreover, as described later, the state of the inner wall of the processing container 11 can be determined based on the difference in plasma luminescence intensity in multiple directions. In addition, in the case of detecting light having optical axes in multiple directions passing through the same window 41, when the difference in plasma luminescence intensity in multiple directions is used to determine the state of the inner wall, the influence of blurring of the window 41 and the like can be eliminated.

[0046] exist Figure 3 In the figure, “IL1” represents the following value: Figure 2 The result of measuring the first plasma emission intensity of a specified wavelength using light having a first optical axis L1 as shown is normalized by the plasma emission intensity when measured at other flow rates. In addition, "IL2" represents the following values: Figure 2 The result obtained by measuring the second plasma emission intensity of a specified wavelength using the light having the second optical axis L2 shown in the figure is a value obtained by normalizing the plasma emission intensity when measuring at other flow rates. Accordingly, there is no significant difference between the result obtained by measuring the state of the plasma at the center of the processing container 11 using the light having the first optical axis L1 and the result obtained by measuring the state of the plasma at the end of the processing container 11 using the light having the second optical axis L2. In other words, it can be seen that the measurement result of the state of the plasma at the center of the processing container 11 and the measurement result of the state of the plasma at the end of the processing container 11 are disturbed to the same extent.

[0047] Therefore, the first plasma emission intensity ( Figure 4 The difference between the black circle (IL1) in (a) and the second plasma emission intensity (white circle (IL2)) measured at the same timing using light having the second optical axis L2. Figure 2 In the example of FIG. 1 , the first optical axis L1 passes through the plasma generation region P. Therefore, the first plasma emission intensity (black circle ( IL1 )) measured using the light having the first optical axis L1 represents the state of the plasma.

[0048] On the other hand, the second optical axis L2 reaches the top wall of the processing container 11 without passing through the plasma generation region P. Therefore, the second plasma emission intensity (white circle (IL2)) measured using the light having the second optical axis L2 indicates the state of the plasma diffused from the plasma generation region P and the state of the wall.

[0049] Therefore, by calculating Figure 4 The difference between the first plasma luminescence intensity and the second plasma luminescence intensity indicated by the arrow in (a) can offset the plasma state and interference. Figure 4 The state of the inner wall of the processing container 11 is determined by the difference between the first plasma emission intensity and the second plasma emission intensity (circle (IL1-IL2)) in (b).

[0050] [Measurement and processing of plasma emission intensity]

[0051] Below, refer to Figure 5 The following describes the plasma emission intensity measurement process performed to determine the state of the wall. Figure 5 1 is a flowchart showing a process of measuring plasma emission intensity according to one embodiment.

[0052] When the present process is started, the detector 40 measures the first plasma emission intensity based on optical emission spectroscopy (OES) using light having a first optical axis L1 passing through the plasma generation region P (step S1). Next, the detector 40 measures the second plasma emission intensity based on optical emission spectroscopy using light having a second optical axis L2 not passing through the plasma generation region P (step S2).

[0053] Next, the control unit 30 determines whether to end the measurement (step S3). When the control unit 30 determines that the measurement is to be ended, the present process is ended. When the control unit 30 determines that the measurement is not to be ended, it determines whether the next measurement time has arrived (step S4). Moreover, the control unit 30 waits until the next measurement time has arrived. When the control unit 30 determines that the next measurement time has arrived, it returns to step S1. In step S1 and subsequent steps, the next first plasma luminescence intensity and the next second plasma luminescence intensity are measured. Through the above-mentioned process, steps S1 to S4 are repeated to measure the first plasma luminescence intensity and the second plasma luminescence intensity at predetermined intervals until the measurement is completed. The first plasma luminescence intensity and the second plasma luminescence intensity measured at predetermined intervals are sent to the control unit 30.

[0054] [Aging treatment]

[0055] Next, refer to Figure 6 and Figure 7The aging treatment using the difference between the first plasma emission intensity and the subsequent second plasma emission intensity will be described. Figure 6 1 is a flowchart showing an aging process according to one embodiment. Figure 7 1 is a diagram for explaining the start and end of the conditioning process according to one embodiment. The following describes the conditioning process by citing the aging process and the dry cleaning process as an example. Figure 7 The horizontal axis represents time, but it can also represent the number of product wafers and virtual wafers.

[0056] When to start Figure 6 When the processing is performed, the control unit 30 determines whether to start the aging process (step S10). Figure 7 In the example of FIG. 1 , the aging process is set to start at a preset time T0. Therefore, the control unit 30 determines that the aging process is started when the time T0 is reached, and performs the aging process in the processing container 11 (step S12). In the aging process, in order to stabilize the inside of the processing container 11, plasma is generated under the same conditions as the process conditions for processing the wafer, and plasma processing is performed in the processing container 11.

[0057] During the aging process, the measured values ​​of the first plasma emission intensity and the second plasma emission intensity are sent from the detector 40 to the control unit 30 at predetermined intervals. Figure 6 As shown, the control unit 30 obtains the measured values ​​of the first plasma emission intensity and the second plasma emission intensity, and calculates the difference between the two (step S14).

[0058] Next, the control unit 30 determines whether the calculated difference is within a normal range (step S16 ). Figure 7 The black circle represents the difference between the first plasma emission intensity and the second plasma emission intensity (hereinafter, also referred to as "difference"). Figure 7 During the aging period, the first and second calculated difference marks are outside the normal range indicated by the dotted line. On the other hand, the third to sixth calculated difference marks during the aging period are within the normal range.

[0059] like Figure 6 As shown, in step S16, the control unit 30 determines that the first and second calculated differences are outside the normal range, and returns to step S12 to continue the aging process. On the other hand, in step S16, the control unit 30 determines that the third to sixth calculated differences are within the normal range, and proceeds to step S18.

[0060] In step S18, the control unit 30 determines whether a second predetermined time has elapsed since the environment in the normal range. The second predetermined time is a preset value and is set to a time that can be determined to stabilize the environment in the processing container 11 to a normal state through the aging process.

[0061] The control unit 30 determines that the second predetermined time or longer has not elapsed since the time when the third to fifth calculated differences fell within the normal range, based on the third to fifth calculated differences, and repeats the processing of step S12 to step S18 .

[0062] On the other hand, in step S18, the control unit 30 determines that the second predetermined time or longer has elapsed since the temperature was within the normal range based on the sixth calculated difference, and ends the aging process (step S20), thereby terminating the present process. Figure 7 In the example of FIG. 1 , the judgment of ending the aging treatment is performed at time T1.

[0063] Based on this, the difference between the first plasma emission intensity and the second plasma emission intensity determines whether the inner wall state of the processing container 11 is within the normal range. If the inner wall state of the processing container 11 is determined to be stable and normal, the aging is determined to be completed.

[0064] [Dry cleaning process]

[0065] Next, refer to Figure 8 and Figure 7 A dry cleaning process using the difference between the first plasma emission intensity and the subsequent second plasma emission intensity will be described. Figure 8 1 is a flowchart showing a dry cleaning process according to one embodiment.

[0066] When to start Figure 8 During the dry cleaning process, the control unit 30 controls the transfer arm (not shown) to move the wafer W into the processing container 11 (step S30). Next, the control unit 30 applies HF power and LF power based on the process conditions set in the process, supplies a specified gas to generate plasma, and performs plasma processing on the wafer W (step S32).

[0067] Next, the control unit 30 controls the transfer arm (not shown) to move the wafer W in and out of the processing container 11 after the plasma treatment (step S34). Next, the control unit 30 obtains the measured values ​​of the first plasma emission intensity and the second plasma emission intensity, and calculates the difference between the two (step S36). Then, the control unit 30 determines whether the difference between the first plasma emission intensity and the second plasma emission intensity exceeds a first threshold value (step S38). The first threshold value is pre-set to a value that is judged to be necessary to perform dry cleaning because the state of the wall in the processing container 11 is deteriorated due to the deposition of deposits on the wall, etc.

[0068] In step S38, when the control unit 30 determines that the difference does not exceed the first threshold, it determines that it is not necessary to start dry cleaning of the processing container 11 including the wall, and returns to step S30. Then, the control unit 30 loads the next wafer W and repeats the processes of steps S32 to S38.

[0069] In step S38 , when the control unit 30 determines that the difference exceeds the first threshold value, the control unit 30 executes dry cleaning (step S40 ).

[0070] exist Figure 7 In the example of , the upper limit of the normal range is set to the first threshold. In this case, the processing of the wafer W is performed until the difference exceeds the first threshold.

[0071] exist Figure 7 , the difference shown immediately before time T2 exceeds the first threshold value. Therefore, it is determined that dry cleaning starts at this time point. As a result, Figure 7 In the example shown in FIG. 1 , dry cleaning starts at time T2.

[0072] like Figure 8 As shown, the control unit 30 determines whether the calculated difference is within the normal range (step S42). The control unit 30 continues the dry cleaning process of step S40 until the calculated difference becomes within the normal range. In step S42, when the control unit 30 determines that the calculated difference is within the normal range, it determines whether a first predetermined time or more has passed since it became within the normal range. (step S44).

[0073] The first predetermined time is a preset value, and is set to a time that can be determined to stabilize the environment in the processing container 11 to a normal state through cleaning.

[0074] When control unit 30 determines that the first predetermined time or longer has not elapsed since the plasma emission intensity entered the normal range based on the difference between the first plasma emission intensity and the second plasma emission intensity, it repeats the processing of step S40 to step S44 .

[0075] On the other hand, when the control unit 30 determines that the first predetermined time has elapsed from the time when the difference falls within the normal range, the control unit 30 ends the dry cleaning (step S46 ) and then returns to step S30 to repeat the subsequent processing.

[0076] exist Figure 7 In the example, after the difference between the first plasma emission intensity and the second plasma emission intensity exceeds the first threshold, the dry cleaning is terminated at time T3 after the first processing time has elapsed since the difference became within the normal range.

[0077] Therefore, in Figure 7The next wafer W is processed at time T3 to T4. Then, when the difference between the first plasma emission intensity and the second plasma emission intensity exceeds the first threshold again, it is determined that dry cleaning is required, and dry cleaning is started at time T4.

[0078] In addition, Figure 8 In the example of FIG. 1 , the wafer W is processed immediately after the dry cleaning is completed, but the present invention is not limited thereto. For example, a predetermined film may be pre-coated within a predetermined time after the dry cleaning is completed, and then the wafer W may be processed.

[0079] As described above, according to the plasma processing involved in this embodiment, the state of the wall is determined based on the difference between the first plasma luminescence intensity for detecting the state of the plasma and the second plasma luminescence intensity for detecting the state of the plasma and the state of the wall. Thus, it is possible to end the aging, start the dry cleaning, and end the dry cleaning at appropriate timings according to the determined state of the wall. Thus, it is possible to avoid the generation of particles in the processing container 11, which deteriorates the environment in the processing container 11 and reduces the productivity of wafer processing.

[0080] [Modification 1]

[0081] Next, refer to Fig. 9 and Fig.10 A dry cleaning process according to Modification 1 of one embodiment will be described. Fig. 9 This is a flowchart showing a dry cleaning process according to Modification 1 of one embodiment. Fig.10 FIG. 4 is a diagram showing an example of a detector 40 according to an embodiment. Fig. 9 In each step of the dry cleaning process according to the first variation of Figure 8 The steps of the same dry cleaning process are marked with the same step numbers.

[0082] like Fig.10 As shown, in the dry cleaning process according to the first modification, the control unit 30 detects light having three or more optical axes substantially evenly distributed in the circumferential direction of the wall of the processing container 11 through the detector 40. Fig.10 In the example of , light having five optical axes is detected. A plurality of detectors 40 may also be used to detect light having three or more optical axes approximately evenly distributed in the circumferential direction of the wall of the processing container 11. The first optical axis L1 passes through the plasma generation region P and reaches the side wall of the processing container 11. The light having the first optical axis L1 is used to measure the first plasma luminescence intensity. The second optical axes L2 to L5 reach the side wall of the processing container 11 without passing through the plasma generation region P. The lights having the second optical axes L2 to L5 are respectively used to measure the second plasma luminescence intensity.

[0083] When to start Fig. 9 When the wafer is processed, the wafer processing of steps S30 to S34 is performed. Next, the control unit 30 obtains the measured values ​​of the first plasma emission intensity measured using the light having the first optical axis L1 and the second plasma emission intensity measured using the light having the second optical axes L2 to L5 respectively. Then, the control unit 30 calculates the difference between the obtained first plasma emission intensity and each second plasma emission intensity (step S50). Thus, the difference (multiple differences) between the first plasma emission intensity and each second plasma emission intensity of the plurality of second plasma emission intensities is calculated.

[0084] Next, the control unit 30 determines whether at least one of the calculated differences exceeds the first threshold value (step S52). If the control unit 30 determines that none of the calculated differences exceeds the first threshold value, it determines that it is not necessary to start dry cleaning. Then, the control unit 30 returns to step S30, loads the next wafer W, and repeats the processing of steps S32 to S34, S50, and S52.

[0085] In step S52 , when the control unit 30 determines that at least any one of the calculated differences exceeds the first threshold value, the control unit 30 executes the dry cleaning (step S40 ).

[0086] Next, the control unit 30 determines whether the calculated differences are all within the normal range (step S54). If the calculated differences are all within the normal range, it can be determined that the plurality of points ( Fig.10 The state of the side wall at all points (points R1 to R5) is normal. Thus, it can be confirmed that the condition of the wall is uniform in the circumferential direction.

[0087] Therefore, the control unit 30 continues the dry cleaning process of step S40 until the calculated differences are within the normal range. In step S54, when the control unit 30 determines that the calculated differences are within the normal range, it determines whether a first predetermined time has passed since they were within the normal range (step S44).

[0088] The control unit 30 repeats the processing of steps S40, S54, and S44 until it determines that the first predetermined time or longer has elapsed since all differences between the first plasma emission intensity and the second plasma emission intensity have fallen within the normal range.

[0089] When the control unit 30 determines that the first predetermined time has elapsed since all the differences have fallen within the normal range, the control unit 30 ends the dry cleaning (step S46 ) and then returns to step S30 to repeat the processing after step S30 .

[0090] According to the cleaning process involved in the above-described modification 1, it is possible to confirm that the condition of the wall is uniform in the circumferential direction. Thus, the homogeneity of the condition of the wall can be confirmed in the circumferential direction, so that the cleaning can be started and ended at a more appropriate timing. However, it is also possible that the points where the optical axis reaches the wall are not uniformly dispersed in the circumferential direction. For example, the points where the optical axis reaches can be dispersed on the side wall and the top wall. Thus, the overall condition of the inner wall in the processing container 11 can be grasped with high precision.

[0091] In addition, although the cleaning process is described in the modification 1, the present invention is not limited thereto, and the end condition of aging can also be used. Figure 6 In step S18, when it is determined that the second predetermined time or longer has elapsed since all the differences became within the normal range, the aging is terminated.

[0092] [Modification 2]

[0093] Specifically, refer to Fig.11 The aging treatment according to Modification 2 of one embodiment will be described. Fig.11 FIG. 1 is a flowchart showing an aging process according to a second variation of an embodiment. Fig.11 In each step of the aging treatment according to the second modification example, Figure 6 The same processing steps are marked with the same step numbers.

[0094] In the aging process according to Modification 2, when the control unit 30 determines to start the aging process (step S10 ), the aging process in the processing container 11 is executed (step S12 ).

[0095] During the aging process, the control unit 30 obtains the measured values ​​of the first plasma emission intensity measured using the light having the first optical axis L1 and the second plasma emission intensity measured using the light having the second optical axes L2 to L5 from the detector 40 at predetermined intervals. Furthermore, the control unit 30 calculates the difference between the obtained first plasma emission intensity and each of the second plasma emission intensities (step S60). Thus, the difference (plurality of differences) between the first plasma emission intensity and each of the plurality of second plasma emission intensities is calculated.

[0096] Next, the control unit 30 determines whether all the calculated differences are within the normal range (step S62). If the control unit 30 determines that there is a difference outside the normal range among the calculated differences, it returns to step S12 and continues to perform the aging process. On the other hand, if the control unit 30 determines that all the calculated differences are within the normal range, it proceeds to step S18.

[0097] In step S18, the control unit 30 determines whether the second predetermined time has elapsed since all the calculated differences fell within the normal range. If the control unit 30 determines that the second predetermined time has not elapsed since all the calculated differences fell within the normal range, the control unit 30 returns to step S12 and continues the aging process.

[0098] On the other hand, when the control unit 30 determines that the second predetermined time or longer has elapsed since all the calculated differences fell within the normal range, the control unit 30 ends the aging process (step S20 ) and ends the present process.

[0099] According to the aging treatment according to the second modification described above, it is possible to confirm that the condition of the wall is uniform in the circumferential direction. Thus, the homogeneity of the condition of the wall in the circumferential direction can be confirmed, and the aging can be completed at a more appropriate timing.

[0100] The first plasma luminescence intensity and the second plasma luminescence intensity are obtained by measuring the first plasma luminescence intensity of a specified wavelength and the second plasma luminescence intensity of a specified wavelength using OES. Moreover, in the above-mentioned embodiments and modified examples, the state of the wall is determined by using the difference (subtraction operation) between the measured first plasma luminescence intensity and the second plasma luminescence intensity, but it is not limited to this. For example, the state of the wall can be determined by using the ratio (division operation) of the measured first plasma luminescence intensity and the second plasma luminescence intensity. The relationship between the state of the wall and the state of the plasma can be standardized by the ratio (division operation) of the measured first plasma luminescence intensity and the second plasma luminescence intensity. Thus, the state of the wall can be determined based on the relationship between the state of the wall and the state of the plasma after standardization.

[0101] In addition, in the above-mentioned embodiment and modification, the first predetermined time and the second predetermined time are used, but the number of virtual wafers may be used instead of the time. For example, when virtual wafers are moved in during aging and dry cleaning, the number of virtual wafers moved in may be used to perform the operation. Figure 6 Step S18, Figure 8 and Fig. 9 The determination of step S44.

[0102] In addition, the first plasma emission intensity and the second plasma emission intensity may be measured at the same time or at different times, as long as they are substantially continuous.

[0103] In addition, in the present embodiment and the modified example, the aging process and the dry cleaning process are described as examples of the conditioning process in the processing container 11, but the present invention is not limited thereto. The conditioning process may also be pre-coating of a protective film covering a predetermined film (SiO2 film) in the processing container 11. In this case, the protective film can be formed by performing plasma treatment under conditions different from the process conditions during wafer processing.

[0104] It should be understood that the plasma processing method and plasma processing apparatus involved in one embodiment disclosed herein are illustrative in all aspects and are not restrictive. The above-mentioned embodiment can be modified and improved in various ways without departing from the attached claims and their gist. The matters described in the above-mentioned multiple embodiments can adopt other structures within the scope of non-contradiction, and can be combined within the scope of non-contradiction.

[0105] The plasma processing device disclosed in the present invention can also be applied to any type of device, such as ALD (Atomic Layer Deposition) device, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), radial line slot antenna (Radial Line Slot Antenna), electron cyclotron resonance plasma (ECR), helicon wave plasma (HWP), etc.

Claims

1. A plasma processing method, which is performed using a plasma processing device, wherein the plasma processing device comprises: a processing container; a mounting table, which is arranged in the processing container; a shower head, which is arranged above the mounting table and is used to supply gas into the processing container; a power supply for applying power to the mounting table or the shower head; and a detector for measuring the plasma luminescence intensity in the processing container, wherein plasma is generated above the mounting table or below the shower head in a plan view along the height direction of the processing container by using the gas supplied by the shower head and the power applied by the power supply, The plasma treatment method comprises the following steps: Initiating conditioning within the plasma processing apparatus; detecting a first plasma luminescence intensity using the detector, the first plasma luminescence intensity being an intensity of a first light that passes through the plasma along a first direction in the plan view and is incident on the detector; Detecting a second plasma luminescence intensity using the detector, the second plasma luminescence intensity being an intensity of a second light incident on the detector from an inner wall of the plasma processing device along a second direction, the second light not overlapping with the plasma in the plan view; determining a state of an inner wall of the plasma processing apparatus based on a difference or a ratio between the detected first plasma emission intensity and the second plasma emission intensity; and The adjustment is ended based on the determined state of the inner wall of the plasma processing apparatus.

2. The plasma treatment method according to claim 1, characterized in that: The conditioning is at least any one of dry cleaning, aging, and pre-coating.

3. The plasma treatment method according to claim 1 or 2, characterized in that: In the determination step, when the difference between the detected first plasma emission intensity and the second plasma emission intensity exceeds a first threshold, it is determined that dry cleaning is to be started. When the difference between the first plasma emission intensity and the second plasma emission intensity detected is within a normal range for a period of time longer than a first predetermined time, it is determined that the dry cleaning is to be terminated.

4. The plasma treatment method according to claim 1 or 2, characterized in that: In the determining step, when the difference between the first plasma emission intensity and the second plasma emission intensity detected after the start of aging is within a normal range for a second predetermined time or longer, it is determined that the aging is completed.

5. The plasma treatment method according to claim 1 or 2, characterized in that: The detector has a mechanism for changing the direction of the detected light, The mechanism is used to detect the first light having a first optical axis and the second light having a second optical axis.

6. The plasma treatment method according to claim 1 or 2, characterized in that: The detector includes a first detector and a second detector, the first detector detecting the first light having a first optical axis, and the second detector detecting the second light having a second optical axis, In the plasma processing method, the first light having the first optical axis is detected from the first detector, The second light having the second optical axis is detected from the second detector.

7. The plasma treatment method according to claim 1 or 2, characterized in that: In the detection step, a plurality of second plasma emission intensities measured using the second light having a plurality of second optical axes are detected, wherein the plurality of second optical axes are optical axes reaching a plurality of points on the circumferential direction of the inner wall of the plasma processing device without passing through a plasma generation region. In the determining step, the state of the inner wall of the plasma processing apparatus is determined based on a difference or a ratio between the detected first plasma emission intensity and each of a plurality of second plasma emission intensities.

8. The plasma processing method according to claim 7, characterized in that: In the determination step, when at least one of the differences between the first plasma emission intensity and each of the second plasma emission intensities detected exceeds a first threshold, it is determined that dry cleaning is started. When the difference between the detected first plasma emission intensity and each of the second plasma emission intensities is within a normal range for a period of time longer than a first predetermined time, it is determined that the dry cleaning is terminated.

9. The plasma processing method according to claim 7, characterized in that: In the determination step, when the differences between the first plasma emission intensity and each of the second plasma emission intensities detected are within a normal range for a second predetermined time or longer, it is determined that the aging is completed.

10. A plasma processing device, comprising: a processing container; a mounting table disposed in the processing container; a shower head disposed above the mounting table and used to supply gas into the processing container; A power supply for applying power to the mounting table or the shower head; a detector for measuring the luminous intensity of the plasma in the processing container; and the control department, wherein plasma is generated above the mounting table or below the shower head in a plan view along the height direction of the processing container using the gas supplied by the shower head and the power applied by the power supply, The control unit performs the following steps: Initiating conditioning within the plasma processing apparatus; detecting a first plasma luminescence intensity using the detector, the first plasma luminescence intensity being an intensity of a first light that passes through the plasma along a first direction in the plan view and is incident on the detector; Detecting a second plasma luminescence intensity using the detector, the second plasma luminescence intensity being an intensity of a second light incident on the detector from an inner wall of the plasma processing device along a second direction, the second light not overlapping with the plasma in the plan view; determining a state of an inner wall of the plasma processing apparatus based on a difference or a ratio between the detected first plasma emission intensity and the second plasma emission intensity; and The adjustment is ended based on the determined state of the inner wall of the plasma processing apparatus.

Images