Plasma processing apparatus and plasma processing method

Abstract

The purpose of the present disclosure is to provide a technique capable of improving the yield of processing. A device (CPU 107) of a plasma processing device (100) adjusts the supply of high-frequency power using information indicating the magnitude of the high-frequency power detected in a period (PA) after a predetermined time (TMV) elapses after the start of either a period (PA) in which the amplitude of the high-frequency power is large or a period (PB) in which the amplitude of the high-frequency power is small. The device (CPU107) has a function of variably adjusting the length (TMV) of the predetermined time.

Description

Technical Field

[0001] The present disclosure relates to a plasma processing device and a plasma processing method. The present disclosure particularly relates to a plasma processing device that has a processing chamber in a vacuum container and a sample stage in which a sample such as a semiconductor wafer is arranged, and forms plasma in the processing chamber to process the sample, and relates to a plasma processing method that supplies high-frequency power output from a high-frequency power supply to an electrode provided on the sample stage, and implements plasma control to process the sample. Background Art

[0002] Japanese Patent Application Laid-Open No. 2014-022482 (Patent Document 1) has been proposed as a technology for a plasma processing apparatus. Patent Document 1 discloses a plasma processing apparatus that temporally modulates a high-frequency power for plasma generation and a high-frequency bias power.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-022482 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The following are technologies studied by the present inventors and are not publicly known technologies.

[0008] The present inventors have studied a technique for time-modulating (pulsing on / off) the high-frequency power output from a high-frequency power supply and supplying it to an electrode disposed on a sample stand. In this case, the output of the high-frequency power supply preferably detects the traveling wave through a directional coupler built into the high-frequency power supply, and feedback (FB) control is performed inside the high-frequency power supply so that the peak-to-peak voltage (hereinafter referred to as Vpp) as the output (output range) of the high-frequency power supply is constant. In terms of the characteristics of the plasma load, if this feedback control is performed during the entire time during which the output of the high-frequency power supply is turned on, the control becomes unstable, and it is known that there is a problem of unstable output power of the high-frequency power supply. Therefore, the present inventors have studied stopping the feedback control in the time domain of a portion of the on-time period (or output on-time) of the output of the high-frequency power supply, defining the prescribed time (stop time) for stopping the feedback control as a "masking time value", and maintaining the "masking time value" as an internal parameter of the high-frequency power supply.

[0009] According to the research of the present inventors, it is known that in the above-mentioned technology, the following aspects are not sufficiently considered, thus causing problems. It is known that for the "shielding time value", the optimal value for stably controlling the output of the high-frequency power supply is different according to the conditions involved in the plasma load and the traveling wave power value. In addition, the "shielding time value" is set to a fixed value according to the device specifications of the plasma processing device and the manufacturing process of the semiconductor device. However, it is known that due to the expansion of the power output range of the high-frequency power supply, if the "shielding time value" is set to a fixed value, it is difficult to perform stable feedback control under all load conditions. That is, as the output range of the high-frequency power supply expands, it may be difficult to select a fixed shielding time value that satisfies all output ranges.

[0010] As described above, in this research technology, since the output range of the high frequency power source is expanded, the shielding time value that satisfies all output power ranges is not considered, so the fluctuation and deviation of the RF voltage relative to the target value become larger. In addition, the size of the shape obtained as a result of the plasma processing of the semiconductor wafer as a sample deviates from the expected size, and there is a problem that the yield of the processing by the plasma processing device is impaired.

[0011] An object of the present disclosure is to provide a technology (a plasma processing apparatus and a plasma processing method) capable of improving a processing yield.

[0012] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0013] Solutions to Solve Problems

[0014] The outline of the representative aspects of the present disclosure will be briefly described as follows.

[0015] A plasma processing apparatus according to one embodiment of the present disclosure comprises: a processing chamber disposed inside a vacuum container and forming plasma inside; a sample stage disposed inside the processing chamber and carrying a semiconductor wafer, which is an object to be processed using the plasma; an electrode disposed inside the sample stage and supplied with high-frequency power during the processing of the semiconductor wafer; and a control device that adjusts the supply of the high-frequency power from a high-frequency power supply, wherein:

[0016] The high frequency power is supplied from the high frequency power source while repeating a period of large amplitude and a period of small amplitude in a predetermined cycle during processing of the semiconductor wafer.

[0017] The control device adjusts the supply of the high-frequency power using information indicating the magnitude of the high-frequency power detected in the period after a prescribed time has passed since the start of either the period with large amplitude or the period with small amplitude, and has a function of variably adjusting the length of the prescribed time.

[0018] Effects of the Invention

[0019] According to a plasma processing apparatus according to one aspect of the present disclosure, it is possible to improve a processing yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a longitudinal sectional view schematically showing the outline of the structure of the plasma etching device according to the embodiment.

[0021] Figure 2 2 is a block diagram of the masking time control of the embodiment.

[0022] Figure 3 This is a diagram conceptually showing the masking time value used for feedback control of a high-frequency power supply.

[0023] Figure 4 1 is a flowchart illustrating the selection of a masking time value of a high frequency power source by the device CPU.

[0024] Figure 5 This is an example of a table for explaining the selection of the masking time value of the high-frequency power supply by the device CPU.

[0025] Fig. 6A This is a conceptual diagram of a comparative example in which the masking time value is fixed.

[0026] Figure 6B This is a conceptual diagram of a comparative example in which the masking time value is fixed.

[0027] Fig. 7A 2 is a conceptual diagram of selection of a masking time value according to an embodiment.

[0028] Figure 7B 2 is a conceptual diagram of selection of a masking time value according to an embodiment. DETAILED DESCRIPTION

[0029] The following is an explanation of the embodiments using the accompanying drawings. However, in the following description, the same components are marked with the same reference numerals, and repeated descriptions are sometimes omitted. It should be noted that in order to make the description clearer, the accompanying drawings are sometimes schematically represented compared to the actual method, but this is only an example and does not limit the interpretation of the present disclosure.

[0030] [Example]

[0031] Below, use Figures 1 to 7B Embodiments of the present disclosure are described. Figure 1 It is a longitudinal sectional view schematically showing the outline of the structure of the plasma etching device according to the embodiment. Figure 2 2 is a block diagram of the masking time control of the embodiment.

[0032] Figure 1 The plasma etching apparatus 100 of the present embodiment shown supplies an electric field and a magnetic field for forming plasma to a processing chamber 101 disposed inside a vacuum container 108 , and resonates the motion of electrons caused by the electric field and the magnetic field (Erectron Cyclotron Resonance: ECR), thereby efficiently generating plasma.

[0033] In the figure, a plasma etching device 100 as a plasma processing device includes a processing chamber 101, an electromagnetic wave supply unit 102 as an electromagnetic wave supply device, a gas supply device 103, a high-frequency power supply 104 as a high-frequency power supply device, an automatic integrator 105 as an automatic integrator circuit, and a control device 120. The control device 120 includes a control unit 106 and a device CPU 107.

[0034] A processing chamber 101 is arranged in a vacuum container 108 that maintains a specified vacuum degree. Inside the vacuum container 108, there is a gas injection plate 109 for introducing etching gas, a dielectric window 110 for sealing the vacuum container 108, and a sample mounting electrode 116 serving as a sample table for mounting a semiconductor chip (sample, also called a chip) 115 at a position opposite to the gas injection plate 109.

[0035] In addition, an exhaust on-off valve 111 for exhausting the vacuum container 108, an exhaust speed variable valve 112, and a vacuum exhaust device 113 for exhausting via the exhaust speed variable valve 112 are arranged at the lower part of the processing chamber 101. A plurality of magnetic field generating coils 114 for forming a magnetic field in the processing chamber 101 are provided outside the processing chamber 101.

[0036] The gas supply device 103 is provided to supply gas such as etching gas or inert gas and supplies gas into the processing chamber 101 through the gas supply port provided between the dielectric window 110 disposed at the upper portion of the vacuum container 108 and the gas injection plate 109 .

[0037] In order to propagate the electric field for generating plasma to the processing chamber 101, a waveguide 117 for propagating electromagnetic waves is arranged above the processing chamber 101. The electromagnetic waves oscillated by the magnetron power supply 102 as a radio frequency power supply (RF Power Supply) for generating plasma propagate in the waveguide 117, thereby supplying the electric field to the processing chamber 101. It should be noted that in Example 1, for example, electromagnetic waves such as microwaves with a frequency of 2.45 GHz are used.

[0038] The electromagnetic waves irradiated into the processing chamber 101 via the waveguide 117 act on the excited magnetic field from the magnetic field generating coil 114, thereby ionizing the etching gas in the processing chamber 101. This ionization generates high-density plasma.

[0039] Furthermore, the sample placement electrode 116 is connected to the high frequency power source 104 via the automatic integrator 105. The fundamental frequency of the high frequency power source 104 is, for example, 400 kHz. The automatic integrator 105 changes the impedance between the high frequency power source 104 and the sample placement electrode 116. The sample placement electrode 116 is arranged inside the sample stage, and in other words, it can be an electrode to which high frequency power is supplied from the high frequency power source 104 during the processing of the semiconductor wafer 115.

[0040] The etching parameters such as the output of the high-frequency power supply 104, TM duty, and TM frequency preset in the device CPU 107 are sent to the control unit 106 to control the output level of the supply power of the high-frequency power supply 104. Through the control of the output level, the high-frequency power supply 104 switches the output level of the supply power in a predetermined periodic pattern and outputs it. The output supply power is applied to the automatic integrator 105 and the sample mounting electrode 116, and a bias potential is formed on the wafer 115, thereby inducing charged particles in the plasma to the wafer 115 through the potential difference between the plasma potential of the generated plasma and the bias potential. TM duty and TM frequency will be described later.

[0041] like Figure 2 As shown, the device CPU 107 is configured to switch the shielding time setting value (also referred to as shielding time value) MTV of the high frequency power source 104 based on the settings of TM Duty, the output power range of the high frequency power source 104, the gas flow rate to the processing chamber 101, and the pressure range of the processing chamber 101. That is, the device CPU 107 calculates the shielding time setting value MTV based on the settings of TM Duty, the output power range of the high frequency power source 104, the gas flow rate to the processing chamber 101, and the pressure range of the processing chamber 101. The calculated shielding time setting value MTV is supplied to the control unit 106, and then supplied from the control unit 106 to the high frequency power source 104. The high frequency power source 104 is configured to perform feedback control of the high frequency power (PoutRF) of the high frequency power source 104 using the received shielding time value MTV. The high frequency power (PoutRF) of the high frequency power source 104 is transmitted to the chamber as the processing chamber 101 via the automatic integrator 105, and is transmitted to the sample placement electrode 116 in the chamber. It should be noted that, in this example, the switching of the masking time setting value MTV can also be applied to the magnetron power supply 102 (see Figure 1 ) and automatic integrator 105.

[0042] The relationship between TM Duty, the output of the power supplied by the high-frequency power source 104 , the cycle mode, the processing pressure of the processing chamber 101 , and the mask time setting value MTV of the high-frequency power source 104 will be described later.

[0043] The high frequency power (PoutRF) thus supplied to the sample placement electrode 116 acts on the plasma-like etching gas and the wafer 115 , thereby performing a dry etching process on the wafer 115 .

[0044] It should be noted that the gas injection plate 109, the sample placement electrode 116, the magnetic field generating coil 114, the exhaust on-off valve 111, the exhaust speed variable valve 112 and the wafer 115 are arranged axially symmetrically with respect to the central axis of the processing chamber 101. Therefore, the flow of the etching gas, the free radicals and ions generated by the plasma, and the reaction products generated by etching are introduced coaxially with respect to the wafer and discharged coaxially. This axially symmetrical flow has the effect of improving the etching rate and the uniformity of the etching shape within the wafer surface.

[0045] <About output setting of high frequency power supply 104>

[0046] Next, use Figure 3 The output control method of the high-frequency power supply 104 will be described. Figure 3 1 is a diagram conceptually showing masking time values ​​used for feedback (FB) control of the high frequency power source 104. Figure 3 In FIG. 1 , Vpp represents the peak-to-peak voltage as the output (output range) of the high-frequency power supply 104 .

[0047] The high frequency power PoutRF outputted by the high frequency power source 104 is supplied from the high frequency power source 104 in a predetermined cycle T1 during the processing of the semiconductor wafer 115, repeating a period PA during which the amplitude of the high frequency power PoutRF is large and a period PB during which the amplitude of the high frequency power PoutRF is small. The period PB during which the amplitude of the high frequency power PoutRF is small can be said to be a period during which the amplitude of the high frequency power PoutRF is 0 (zero) or the amplitude is so small that it can be regarded as 0 (zero). The cycle T1 is also referred to as a predetermined cycle pattern.

[0048] In addition, the high frequency output PoutRF of the high frequency power supply 104 detects the traveling wave through a directional coupler (not shown) built into the high frequency power supply 104, and FB control FBC is performed in the high frequency power supply 104 to make the traveling wave power constant. In order to define the timing of FB control FBC of the output PoutRF of the high frequency power supply 104, a parameter such as the masking time value MTV is used.

[0049] The masking time value MTV defines the period (FB control FBC stop period) during the on period of the output PoutRF of the high frequency power source 104 (or during the period PA when the amplitude of the high frequency power PoutRF is large) during which the FB control FBC is stopped. The masking time value MTV can be said to be a predetermined time during which the FB control FBC is stopped.

[0050] It is preferred to perform FB control FBC at a time when the output setting value of the high frequency power supply 104 is consistent with the actual output power value of the high frequency power supply 104. However, the output power of the high frequency power supply 104 changes the output waveform of the high frequency power supply 104 due to the influence of the on-time of the output of the high frequency power supply 104 and the plasma load. As a result, the timing at which the high frequency power supply 104 actually outputs the power value set to the output setting value also changes, so the optimal timing for FB control FBC changes. When FB control FBC is not performed at the optimal timing, the waveform deviated from the output setting value of the RF bias power supply (high frequency power supply 104) during the period when FB control FBC should have been stopped is used for FB control FBC, and accurate FB control FBC cannot be performed. As a result, a difference occurs between the output setting value of the RF bias power supply and the actual output value. If the difference exceeds ±0.5% of the output setting value, it becomes a significant difference in the performance of the RF bias power supply, so it is desired to avoid it.

[0051] Here, TM Duty (also referred to as Duty: Duty ratio) refers to the ratio (ratio) of the period PA during which the amplitude of the high-frequency power PoutRF is large to the period T1 (one cycle period T1). TM Duty can be calculated by (TM Duty = (PA / T1) × 100%). TM Frequency can be expressed by (1 / T1).

[0052] <About the Operation of the Device CPU 107>

[0053] Next, use Figure 4 The operation of the flowchart of the device CPU 107 in the control device 120 will be described. Figure 4 1 is a flowchart for explaining the selection of the masking time value of the high frequency power source 104 by the device CPU 107. Here, each step S301 to S303 will be explained in the order of the step numbers shown in the figure.

[0054] Step S301:

[0055] The device CPU 107 obtains the etching parameters of the corresponding etching step before the predetermined time T4 of the etching step set in the microwave plasma etching device 100. The time T4 is determined by considering the delay time of the setting signal of the plasma processing device 100 and the delay time of the reflection of the setting signal of the high-frequency power supply 104. Based on the etching parameters, the device CPU 107 determines to output the set masking time value MTV to the high-frequency power supply 104. Then, the operation of the device CPU 107 is transferred to step S302.

[0056] Step S302:

[0057] The device CPU 107 selects the masking time value MTV from the appendix. Figure 5 Then, the operation of the device CPU 107 moves to step S303.

[0058] Step S303:

[0059] The device CPU 107 sends the mask time value MTV selected in step 303 to the control unit 106 .

[0060] Here, if the current etching step is the final etching step, the device CPU 107 ends the action of this flowchart. If the current etching step is not the final etching step, the device CPU 107 refers to the etching parameters of the corresponding next etching step before the predetermined time T4 of the next etching step input, and transfers the action to step 301. In other words, Figure 4 The flowchart of FIG. 1 has a feature that the mask time value MTV can be made variable in each etching step. That is, making the mask time value MTV variable means variably adjusting the length of a prescribed time for stopping the FB control FBC.

[0061] That is, the plasma processing apparatus 100 can be summarized as follows. The plasma processing apparatus 100 includes: a processing chamber 101, which is arranged inside a vacuum container 108 and forms plasma inside; a sample stage 116, which is arranged inside the processing chamber 101 and carries a semiconductor wafer 115 as a target for processing using plasma; an electrode (116), which is arranged inside the sample stage 116 and supplies high-frequency power during the processing of the semiconductor wafer 115; and a control device 120 (106, 107) that adjusts the supply of high-frequency power from the high-frequency power supply 104.

[0062] Furthermore, the high frequency power is configured to be supplied from the high frequency power source 104 while repeating a period PA with a large amplitude and a period PB with a small amplitude at a predetermined cycle T1 during the processing of the semiconductor wafer 115 .

[0063] Then, the device CPU 107 of the control device 120 uses the period PA in which the high-frequency power has a large amplitude and the period PB in which the high-frequency power has a small amplitude (in Figure 3 In the case of a large amplitude period PA), a predetermined time has passed since the start of the period PA (in Figure 3 , corresponding to the period after the masking time value MTV) (in Figure 3 In the example, the directional coupler controls the supply of high-frequency power (FB control FBC) based on the information of the magnitude of the high-frequency power detected during the period (described as the period of FB control FBC) (information based on the detection result of the traveling wave of the directional coupler). Furthermore, the device CPU 107 of the control device 120 is configured to variably adjust the length of the prescribed time (in the period of FB control FBC). Figure 3 In the function of shielding time value MTV).

[0064] In addition, the plasma processing method using the plasma processing apparatus 100 can be summarized as follows. That is, the plasma processing method is a plasma processing method in which a semiconductor wafer 115 to be processed is placed on a sample stage 116 disposed inside a vacuum container 108 and disposed inside a processing chamber 101 in which plasma is formed, and during the processing of the semiconductor wafer, a high-frequency power is supplied from a high-frequency power source 104 to an electrode (116) disposed inside the sample stage 116, and the semiconductor wafer 115 is processed using plasma.

[0065] The high frequency power is supplied from the high frequency power source 104 so as to repeat the period PA with large amplitude and the period PB with small amplitude at a predetermined cycle T1. Figure 3 In the case of a large amplitude period PA), a predetermined time has passed since the start of the period PA (in Figure 3 , corresponding to the period after the masking time value MTV) (in Figure 3 In the period recorded as FB control FBC), the information of the magnitude of the high frequency power detected (information based on the detection result of the traveling wave of the directional coupler) is adjusted, and the length of the prescribed time (in the period recorded as FB control FBC) is variably adjusted. Figure 3 , corresponding to the masking time value MTV).

[0066] Figure 5 This is an example of a table for explaining selection of a masking time value of the high-frequency power source 104 by the device CPU 107 . Figure 5The parameters (parameter 1 (PAR1), parameter 2 (PAR2), parameter 3 (PAR3), and parameter 4 (PAR41)) are determined by the conditions actually used in the etching process. The optimal shielding time value MTV varies depending on the maximum output power of the high-frequency power supply 104 installed. Therefore, when the high-frequency power supply 104 is installed in the etching device 100, the optimal shielding time value MTV for the combination of various parameters such as TM Duty, output power range, gas flow rate, and processing pressure range is measured in advance, and before the flowchart of the automatic selection of the shielding time value MTV disclosed in the present invention is pre-introduced, it is input as a table and stored in the device CPU 107. Regarding the prior measurement conditions, Figure 5 The following is an example of parameters 1 to 4 used for etching.

[0067] Parameter 1 (PAR1): TM Duty = (PA / T1) × 100%):

[0068] 1) More than 50%,

[0069] 2) Less than 50% (minimum pulse width).

[0070] Parameter 2 (PAR2): Processing pressure range (processing pressure) during etching process in the processing chamber 101:

[0071] 1) Below 5mTorr,

[0072] 2) Greater than 5mTorr and less than 10mTorr,

[0073] 3) Greater than 10mTorr and less than 15mTorr,

[0074] 4) Greater than 15mTorr and less than 20mTorr,

[0075] 5) Greater than 20mTorr and less than 25mTorr,

[0076] ···,

[0077] N) is greater than 45mTorr and less than 50mTorr.

[0078] Parameter 3 (PAR3): Output power range (power setting) of the high-frequency power PoutRF output by the high-frequency power source 104:

[0079] 1) Below 1000W,

[0080] 2) Greater than 1000W and less than 2000W,

[0081] 3) Greater than 2000W and less than 4000W.

[0082] Parameter 4 (PAR4): Gas flow rate of argon (Ar) gas during etching process:

[0083] 1) Below 200ml / min,

[0084] 2) Greater than 200 ml / min.

[0085] Under the conditions of each combination of parameters 1-4, the masking time value MTV is changed in 10% increments. The masking time value MTV when the output is closest to the actual value relative to the output power range set by parameter 3 (PAR3) is measured and taken into account. Figure 5 Thus, by using the recorded Figure 5 The table can automatically select the masking time value MTV.

[0086] By pre-determination Figure 5 The table is stored in the device CPU 107, and FB control can be performed without being affected by parameters 1-4 (TM Duty, output power range, gas flow rate, and processing pressure range), so that the error between the output setting value and the actual output value of the high-frequency power supply 104 is within the prescribed allowable range.

[0087] The device CPU 107 reads the Figure 5 The mask time value MTV is automatically selected by comparing the data in the table with the input etching parameters 1-4 of TM Duty, output power range, gas flow rate, and process pressure range.

[0088] That is, the method is configured to use a method that uses at least one value selected from a plurality of parameters including the pressure in the processing chamber 101 during processing of the semiconductor wafer, the magnitude of the high frequency power (PoutRF) outputted from the high frequency power source 104, and the ratio of the period PA with large amplitude to the period PB with small amplitude in the cycle T1 (here, TM Duty) and the relationship between the predetermined period (masking time value MTV). Figure 5 The length of the prescribed time (masking time value MTV) is adjusted according to the processing conditions of the semiconductor wafer according to the table (data). Furthermore, in this example, the masking time value MTV is configured to be automatically selected. In addition, in a plurality of processes constituting the processing of one semiconductor wafer performed in the processing chamber 101, the length of the prescribed time (masking time value MTV) is adjusted according to the processing conditions for each process.

[0089] exist Figure 5 In the embodiment, it is configured to be able to add or delete not only the above-mentioned parameters 1-4, but also the parameters of the power of the magnetron power supply 102, the output frequency of the high-frequency power supply 104, the TM frequency set for the high-frequency power supply 104, the applied current of the magnetic field generating coil 114, and the temperature of the sample mounting electrode 116.

[0090] in addition, Figure 5 The data in the table is not only stored in the device CPU 107, but can also be directly input to the computer PC mounted on the device CPU 107, so that the computer PC and the device CPU 107 communicate and are reflected at any time.

[0091] Through the above series of operations, the device CPU 107 can transmit the optimal masking time value MTV set to the high-frequency power source 104 via the control unit 106 in each of the plurality of etching steps.

[0092] <Effects of Example>

[0093] The embodiment has the following effects.

[0094] Fig. 6A , Figure 6B , Fig. 7A , Figure 7B This is a conceptual diagram of a waveform output from the high-frequency power source 104. This waveform is an assumed example and is not necessarily output from the high-frequency power source 104. Fig. 6A , Figure 6B , Fig. 7A , Figure 7B That kind of waveform.

[0095] The optimum value of the timing of the FB control in the power output from the high-frequency power source 104 changes depending on the influence of the high-frequency output power, the on-time, and the plasma load.

[0096] Fig. 6A , Figure 6B This is a conceptual diagram of a comparative example in which the masking time value is fixed. Fig. 7A , Figure 7B This is a conceptual diagram of the masking time value selection (variable) according to the embodiment.

[0097] and Fig. 6A , Figure 6B The difference is that the rise of the waveform output from the high frequency power supply 104 changes due to the influence of the high frequency output power, the on time, and the plasma load. If the FB region is constant control, as described above, the FB control is not performed at the optimal value, and the waveform deviated from the output setting value of the RF bias power supply during the period when the FB control should be stopped is used for the FB control. Therefore, the actual output power different from the output setting value may be output from the high frequency power supply 104.

[0098] Relative to Fig. 6A , Figure 6B ,like Fig. 7A , Figure 7BAs shown, by selecting an appropriate masking time value MTV when the output waveform of the high-frequency power source 104 changes according to TMDuty, the output power range, and the processing pressure range, the timing when the output setting value is close to the actual output power value can be used for the FB control FBC. As a result, the high-frequency power source 104 can recognize a value close to the output setting value and perform the output action of the next waveform.

[0099] As described above, by selecting the mask time value MTV according to the etching parameters of TM Duty, output power range, and process pressure range, the deviation between the output setting value and the actual output of the high frequency power source 104 can be reduced.

[0100] In the present disclosure, the shielding time value MTV of the high frequency power source 104 can be variably set for each processing step. At the start of the processing step of the wafer 115, the shielding time value MTV is variably set according to the output of the high frequency power source 104 and the plasma load conditions set in the recipe. In addition, pre-acquired data indicating the relationship between the pre-acquired output of the high frequency power source 104 and the plasma load conditions and the shielding time value MTV is provided as a parameter table (see Figure 5 ), automatically sets the appropriate masking time value MTV.

[0101] Thus, the optimal masking time value MTV can be set for the high frequency power source 104 for each processing step of the wafer 115. Therefore, stable plasma processing (etching processing) can be achieved. In addition, the yield of the plasma processing (etching processing) can be improved.

[0102] As described above, the problem that the dimensions of the shape obtained as a result of wafer processing deviate from the desired dimensions and the yield of processing by the plasma processing apparatus is impaired is solved.

[0103] Description of reference numerals:

[0104] 100: Plasma etching device (plasma processing device)

[0105] 101: Processing Room

[0106] 104: High frequency power supply

[0107] 106: Control Department

[0108] 107: Device CPU

[0109] 108: Vacuum container

[0110] 115: Semiconductor wafer (sample)

[0111] 116: Sample mounting electrode (sample stand)

[0112] 120: Control device.

Claims

1. A plasma processing device, comprising: a processing chamber, which is arranged inside a vacuum container and forms plasma inside; a sample stage, which is arranged inside the processing chamber and carries a semiconductor wafer, which is an object to be processed using the plasma; an electrode, which is arranged inside the sample stage and is supplied with high-frequency power during the processing of the semiconductor wafer; and a control device, which adjusts the supply of the high-frequency power from a high-frequency power supply, wherein: The high frequency power is supplied from the high frequency power source while repeating a period of large amplitude and a period of small amplitude in a predetermined cycle during processing of the semiconductor wafer. The control device adjusts the supply of the high-frequency power using information indicating the magnitude of the high-frequency power detected in the period after a prescribed time has passed since the start of any one of the period with large amplitude and the period with small amplitude, and the control device has a function of variably adjusting the length of the prescribed time.

2. The plasma processing apparatus according to claim 1, wherein: The length of the specified time is adjusted using data representing the relationship between the specified period and at least one value selected from multiple parameters including the pressure in the processing chamber during processing of the semiconductor chip, the magnitude of the high-frequency power output from the high-frequency power supply, and the ratio of the period with large amplitude to the period with small amplitude in the cycle.

3. The plasma processing apparatus according to claim 1 or 2, wherein: The high-frequency power is supplied by repeating a period in which the amplitude is large and a period in which the amplitude is zero or is so small as to be regarded as zero, in the cycle.

4. The plasma processing apparatus according to claim 1 or 2, wherein: The length of the predetermined time is adjusted according to the processing conditions of the semiconductor wafer.

5. The plasma processing apparatus according to claim 4, wherein: The length of the predetermined time is adjusted according to the processing conditions of a plurality of steps constituting the processing of one semiconductor wafer performed in the processing chamber.

6. A plasma treatment method, wherein: A semiconductor wafer to be processed is placed on a sample stage disposed inside a vacuum container and inside a processing chamber in which plasma is formed, and during the processing of the semiconductor wafer, a high-frequency power is supplied from a high-frequency power supply to an electrode disposed inside the sample stage, and the semiconductor wafer is processed using the plasma, wherein: The high-frequency power is power supplied from the high-frequency power source by repeating a period in which the high-frequency power has a large amplitude and a period in which the high-frequency power has a small amplitude in a predetermined cycle, and the high-frequency power is power regulated using information indicating the magnitude of the high-frequency power detected in a period after a predetermined time has passed since the start of either the period in which the amplitude is large or the period in which the amplitude is small. The length of the prescribed time is variably adjusted.

7. The plasma processing method according to claim 6, wherein: The length of the specified time is adjusted using data representing the relationship between the value of at least one parameter selected from a plurality of parameters including the pressure within the processing chamber during processing of the semiconductor chip, the magnitude of the high-frequency power output from the high-frequency power supply, and the ratio of the period of large amplitude to the period of small amplitude in the cycle, and the specified time.

8. The plasma processing method according to claim 6 or 7, wherein: The high-frequency power is supplied by repeating a period in which the amplitude is large and a period in which the amplitude is zero or is so small as to be regarded as zero, in the cycle.

9. The plasma processing method according to claim 6 or 7, wherein: The length of the predetermined time is adjusted according to the processing conditions of the semiconductor wafer.

10. The plasma processing method according to claim 9, wherein: The length of the predetermined time is adjusted according to the processing conditions of a plurality of steps constituting the processing of one semiconductor wafer performed in the processing chamber.

Images