Plasma processing apparatus and plasma processing method

Abstract

The present disclosure provides some embodiments of a technique capable of improving a processing yield.SOLUTION: The device CPU107 of the plasma processing device 100 adjusts the supply of the radio frequency power by using the information indicating the magnitude of the radio frequency power detected during the period (PA) after the predetermined time (TMV) has elapsed after the start of any period (PA) of the period PA in which the amplitudes of the radio frequency power are large and the period PB in which the amplitudes of the radio frequency power are small. The device CPU107 functions to variably adjust the length (TMV) of the predetermined time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a plasma processing apparatus and a plasma processing method, and more particularly to a plasma processing apparatus that includes a processing chamber in a vacuum vessel and a sample stage for placing a sample such as a semiconductor wafer therein, generates plasma in the processing chamber, and processes the sample, and supplies high-frequency power output from a high-frequency power source to an electrode installed on the sample stage, and performs plasma control to process the sample. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2014-022482 (Patent Document 1) proposes a plasma processing apparatus technology, which discloses a plasma processing apparatus that time-modulates plasma-generating high-frequency power and high-frequency bias power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-022482 Summary of the Invention [Problem to be solved by the invention]

[0004] The following is a technique that has been investigated by the present inventors and is not a publicly known technique.

[0005] The present inventors have investigated a technology for supplying time-modulated (pulsed ON / OFF) RF power output from a radio frequency power generator to an electrode mounted on a sample stage. In this case, the RF power output is preferably detected as a traveling wave by a directional coupler built into the RF power generator, and feedback (FB) control is performed within the RF power generator to maintain a constant peak-to-peak voltage (Vpp), which is the RF power output (output range). Due to the characteristics of the plasma load, this feedback control can become unstable if it is performed throughout the entire ON period of the RF power generator output, resulting in unstable output power. Therefore, the present inventors have investigated a technology for stopping feedback control during a portion of the ON period (or output ON time) of the RF power generator output. The specified time during which feedback control is stopped (stop time) is defined as a "mask time value" and this "mask time value" is stored as an internal parameter of the RF power generator.

[0006] According to the study by the present inventors, it was found that the above-mentioned technology had problems due to insufficient consideration of the following points. It was found that the optimal value of the "mask time value" for stably controlling the output of the high-frequency power supply varies depending on the conditions related to the plasma load and the forward wave power value. In addition, the "mask time value" is set to a fixed value based on the specifications of the plasma processing apparatus and the manufacturing process of the semiconductor device. However, as the power output range of the high-frequency power supply expands, it was found that if the "mask time value" is set to a fixed value, it becomes difficult to perform stable feedback control under all load conditions. In other words, as the output range of the high-frequency power supply expands, it may become difficult to select a fixed mask time value that satisfies all output ranges.

[0007] As described above, this study technique does not take into consideration the selection of a mask time value that satisfies the entire output power range due to the expansion of the output range of the high frequency power source, which results in a large variation or deviation of the RF voltage magnitude from the target value. Also, there is a problem that the dimensions of the shape obtained as a result of plasma processing of the semiconductor wafer sample deviate from the expected ones, which reduces the processing yield of the plasma processing apparatus.

[0008] An object of the present disclosure is to provide a technique (plasma processing method for a plasma processing apparatus) that can improve the processing yield. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0009] A brief summary of representative aspects of this disclosure is as follows. A plasma processing apparatus according to one embodiment of the present disclosure is a plasma processing apparatus comprising: a processing chamber arranged inside a vacuum vessel in which plasma is formed; a sample stage arranged inside the processing chamber on which a semiconductor wafer to be processed using the plasma is placed; an electrode arranged inside the sample stage to which high-frequency power is supplied during processing of the semiconductor wafer; and a control device that adjusts the supply of high-frequency power from a high-frequency power source, wherein the high-frequency power is supplied from the high-frequency power source at a plurality of different values ​​in amplitude or output during processing of the semiconductor wafer, each of which is supplied for a predetermined period of time, and the control device adjusts the supply of high-frequency power using information indicating the magnitude of the high-frequency power detected during a period in which the high-frequency power is set to the different value after a predetermined time has elapsed since the high-frequency power was changed from one of the plurality of different values ​​to another value, and has the function of variably adjusting the length of the predetermined time in accordance with the value of at least one parameter included in the conditions for processing the semiconductor wafer. [Effects of the Invention]

[0010] According to the plasma processing apparatus according to one aspect of the present disclosure, the processing yield can be improved. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a longitudinal sectional view showing a schematic configuration of a plasma etching apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a configuration diagram of the mask time control according to the embodiment. [Figure 3] FIG. 3 is a diagram conceptually showing a mask time value used in feedback control of a high frequency power supply. [Figure 4] FIG. 4 is a flowchart for explaining the selection of the mask time value of the high frequency power supply by the device CPU. [Figure 5] FIG. 5 is an example of a table for explaining the selection of the mask time value of the high frequency power supply by the equipment CPU. [Figure 6A] FIG. 6A is a conceptual diagram of fixing the mask time value according to a comparative example. [Figure 6B] FIG. 6B is a conceptual diagram of fixing the mask time value according to a comparative example. [Figure 7A] FIG. 7A is a conceptual diagram of selection of a mask time value according to an embodiment. [Figure 7B] FIG. 7B is a conceptual diagram of selection of a mask time value according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, examples will be described with reference to the drawings. However, in the following description, the same components will be assigned the same reference numerals, and repeated explanations may be omitted. Note that the drawings may be more schematic than the actual embodiment to make the description clearer, but they are merely examples and do not limit the interpretation of the present disclosure. [Example]

[0013] 1 to 7B, an embodiment of the present disclosure will be described. Fig. 1 is a vertical cross-sectional view showing a schematic configuration of a plasma etching apparatus according to the embodiment. Fig. 2 is a configuration diagram of mask time control according to the embodiment.

[0014] The plasma etching apparatus 100 of this embodiment shown in FIG. 1 supplies an electric field and a magnetic field for forming plasma to a processing chamber 101 disposed inside a vacuum vessel 108, and efficiently generates plasma by causing the respective movements of electrons due to the electric field and magnetic field to resonate (Electron Cyclotron Resonance: ECR).

[0015] In the figure, a plasma etching apparatus 100 serving as a plasma processing apparatus includes a processing chamber 101, an electromagnetic wave supply unit 102 serving as an electromagnetic wave supply device, a gas supply unit 103, a high frequency power supply 104 serving as a high frequency power supply device, an automatic matching box 105 serving as an automatic matching box circuit, and a control device 120. The control device 120 includes a control unit 106 and an apparatus CPU 107.

[0016] A processing chamber 101 is arranged in a vacuum vessel 108 that maintains a predetermined degree of vacuum, and the interior of the vacuum vessel 108 is equipped with a shower plate 109 for introducing an etching gas, a dielectric window 110 for sealing the vacuum vessel 108, and a sample mounting electrode 116 as a sample stage for mounting a semiconductor wafer (also called a sample or wafer) 115 in a position opposite the shower plate 109.

[0017] Further, at the bottom of the processing chamber 101, there are disposed an exhaust opening / closing valve 111 for exhausting the vacuum vessel 108, an exhaust speed variable valve 112, and a vacuum exhaust device 113 for exhausting via the exhaust speed variable valve 112. Outside the processing chamber 101, there are disposed a plurality of magnetic field generating coils 114 for forming a magnetic field in the processing chamber 101.

[0018] The gas supply device 103 is provided to supply a gas, such as an etching gas or an inert gas, from a gas supply port provided between the shower plate 109 and a dielectric window 110 arranged at the top of the vacuum vessel 108, and supplies the gas into the processing chamber 101 through the shower plate 109.

[0019] In order to propagate an electric field for generating plasma into the processing chamber 101, a waveguide 117 for propagating electromagnetic waves is disposed above the processing chamber 101, and electromagnetic waves generated by a magnetron power supply 102, which is a radio frequency power supply for generating plasma, propagate through the waveguide 117, thereby supplying an electric field to the processing chamber 101. In Example 1, for example, microwave electromagnetic waves with a frequency of 2.45 GHz are used.

[0020] The electromagnetic waves irradiated into the processing chamber 101 via the waveguide 117 act on the magnetic field excited by the magnetic field generating coil 114, ionizing the etching gas in the processing chamber 101. This ionization action generates high-density plasma.

[0021] Furthermore, a high frequency power supply 104 is connected to the sample mounting electrode 116 via an automatic matching box 105. The fundamental frequency of this high frequency power supply 104 is, for example, 400 kHz. The automatic matching box 105 changes the impedance between the high frequency power supply 104 and the sample mounting electrode 116. The sample mounting electrode 116 is disposed inside the sample stage, and can be described as an electrode to which high frequency power is supplied from the high frequency power supply 104 during processing of the semiconductor wafer 115.

[0022] Etching parameters such as the output, TM duty, and TM frequency of the high frequency power supply 104, which are preset in the equipment CPU 107, are sent to the control unit 106, which controls the output level of the power supplied by the high frequency power supply 104. By controlling this output level, the high frequency power supply 104 switches the output level of the power supply in a predetermined periodic pattern. The output power supply is applied to the automatic matching box 105 and the sample mounting electrode 116, and a bias potential is formed on the wafer 115, thereby attracting charged particles in the plasma to the wafer 115 due to the potential difference between the plasma potential of the generated plasma and the bias potential. The TM duty and TM frequency will be described later.

[0023] 2, the equipment CPU 107 is further configured to switch the mask time setting value (also referred to as mask time value) MTV of the radio frequency power supply 104 based on the settings of the TM duty, the output power range of the radio frequency power supply 104, the gas flow rate to the processing chamber 101, and the pressure range of the processing chamber 101. That is, the equipment CPU 107 calculates the mask time setting value MTV based on the settings of the TM duty, the output power range of the radio frequency power supply 104, the gas flow rate to the processing chamber 101, and the pressure range of the processing chamber 101. The calculated mask time setting value MTV is supplied to the control unit 106, and further supplied from the control unit 106 to the radio frequency power supply 104. The radio frequency power supply 104 is configured to perform feedback control of the radio frequency power (PoutRF) of the radio frequency power supply 104 using the received mask time value MTV. The radio frequency power (PoutRF) of the radio frequency power supply 104 is transmitted into the chamber, which is the processing chamber 101, via the automatic matching box 105 and then to the sample mounting electrode 116 in the chamber. In this example, the switching of the mask time setting value MTV can also be applied to the magnetron power supply 102 (see FIG. 1) and the automatic matching box 105.

[0024] The relationship between the TM Duty, the output of the power supplied by the high frequency power supply 104, the periodic pattern, the processing pressure in the processing chamber 101, and the mask time set value MTV of the high frequency power supply 104 will be described later.

[0025] The high frequency power (PoutRF) thus applied to the sample mounting electrode 116 acts on the plasma etching gas and the wafer 115, thereby performing a dry etching process on the wafer 115.

[0026] The shower plate 109, sample mounting electrode 116, magnetic field generating coil 114, exhaust on-off valve 111, exhaust speed variable valve 112, and wafer 115 are arranged symmetrically with respect to the central axis of the processing chamber 101. Therefore, the flow of etching gas, radicals and ions generated by plasma, and reaction products generated by etching are introduced coaxially to the wafer and exhausted coaxially. This symmetrical flow has the effect of improving the etching rate and the uniformity of the etching shape within the wafer surface.

[0027] <About the output setting of the high frequency power supply 104> Next, the output control method of the high frequency power supply 104 will be explained using Fig. 3. Fig. 3 is a diagram conceptually showing a mask time value used in feedback (FB) control of the high frequency power supply 104. In Fig. 3, Vpp represents the peak-to-peak voltage, which is the output (output range) of the high frequency power supply 104.

[0028] The high frequency power PoutRF output by the high frequency power supply 104 is supplied from the high frequency power supply 104 at predetermined cycles T1 during processing of the semiconductor wafer 115, with periods PA during which the amplitude of the high frequency power PoutRF is large and periods PB during which the amplitude of the high frequency power PoutRF is small being repeated. 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 is so small that the amplitude can be regarded as 0 (zero). The cycle T1 is also called a predetermined cycle pattern.

[0029] Furthermore, the forward wave of the radio frequency output PoutRF of the radio frequency power supply 104 is detected by a directional coupler (not shown) built into the radio frequency power supply 104, and feedback control FBC is performed within the radio frequency power supply 104 so that the forward wave power is constant. A parameter called a mask time value MTV is used to define the timing of the feedback control FBC of the output PoutRF of the radio frequency power supply 104.

[0030] The mask time value MTV defines the period during which the feedback control FBC is stopped (the period during which the feedback control FBC is stopped) during the ON period of the output PoutRF of the high frequency power supply 104 (or during the period PA during which the amplitude of the high frequency power PoutRF is large). The mask time value MTV can be said to be a predetermined time during which the feedback control FBC is stopped.

[0031] It is desirable to perform the feedback control FBC at a timing when the output set value of the RF power supply 104 and the actual output power value of the RF power supply 104 match. However, the output waveform of the RF power supply 104 changes due to the ON time of the output of the RF power supply 104 and the influence of the plasma load. This changes the timing at which the RF power supply 104 actually outputs the power value set as the output set value, thereby changing the optimal timing to use for the feedback control FBC. If the feedback control FBC is not performed at the optimal timing, a waveform that deviates from the output set value of the RF bias power supply (RF power supply 104) during the period when the feedback control FBC should be stopped will be used for the feedback control FBC, and accurate feedback control FBC will not be performed. As a result, a difference occurs between the output set value and the actual output value of the RF bias power supply. If this difference exceeds ±0.5% of the output set value, it will significantly affect the performance of the RF bias power supply and should be avoided.

[0032] Here, TM Duty (also simply called Duty) is the ratio (proportion) of the period PA during which the amplitude of the high frequency power PoutRF is large to the period T1 (period T1 of one cycle). TM Duty can be calculated as (TM Duty = (PA / T1) x 100%). TM Frequency can be expressed as (1 / T1).

[0033] <Operation of the device CPU 107> Next, the operation of the flowchart of the device CPU 107 in the control device 120 will be described with reference to Fig. 4. Fig. 4 is a flowchart for explaining the selection of the mask time value of the high frequency power supply 104 by the device CPU 107. Here, steps S301 to S303 will be described in the order of the step numbers shown in the figure.

[0034] Step S301: Equipment CPU 107 acquires etching parameters for a corresponding etching step a predetermined time T4 before the etching step to be set in microwave plasma etching equipment 100. This time T4 is determined taking into consideration the delay time for transmission of the setting signal from plasma processing equipment 100 and the delay time for reflection of the setting signal from high frequency power supply 104. In accordance with the etching parameters, equipment CPU 107 determines a mask time value MTV to be set as an output for high frequency power supply 104. Thereafter, the operation of equipment CPU 107 proceeds to step S302.

[0035] Step S302: The device CPU 107 selects a mask time value MTV from the separate table. The operation of selecting a mask time value MTV from the separate table will be described later with reference to Fig. 5. After that, the operation of the device CPU 107 proceeds to step S303.

[0036] Step S303: The device CPU 107 transmits the mask time value MTV selected in step 303 to the control unit 106 .

[0037] If the current etching step is the final etching step, the equipment CPU 107 ends the operation of this flowchart. If the current etching step is not the final etching step, the equipment CPU 107 refers to the etching parameters of the corresponding next etching step a predetermined time T4 before the input next etching step, and proceeds to step 301. In other words, the flowchart of FIG. 4 has the feature that the mask time value MTV can be made variable for each etching step. In other words, making the mask time value MTV variable means that the length of the predetermined time for which the feedback control FBC is stopped can be variably adjusted.

[0038] That is, the plasma processing apparatus 100 can be summarized as follows: The plasma processing apparatus 100 includes a processing chamber 101 disposed inside a vacuum vessel 108 and in which plasma is generated, a sample stage 116 disposed inside the processing chamber 101 and on which a semiconductor wafer 115 to be processed using the plasma is placed, an electrode (116) disposed inside the sample stage 116 and to which high-frequency power is supplied during processing of the semiconductor wafer 115, and a control device 120 (106, 107) that adjusts the supply of high-frequency power from a high-frequency power source 104.

[0039] The high frequency power is supplied from the high frequency power source 104 so as to alternate between a period PA in which the amplitude is large and a period PB in which the amplitude is small at every predetermined cycle T1 during processing of the semiconductor wafer 115.

[0040] Then, the device CPU 107 of the control device 120 adjusts (FB control FBC) the supply of high frequency power using information (information on the detection result of the traveling wave by the directional coupler) indicating the magnitude of the high frequency power detected during a period (corresponding to the period marked FB control FBC in FIG. 3) after a predetermined time (corresponding to the mask time value MTV in FIG. 3) has elapsed after the start of either the period PA or the period PB in which the high frequency power has a large amplitude (corresponding to the period PA in FIG. 3) The device CPU 107 of the control device 120 is configured to have a function of variably adjusting the length of the predetermined time (mask time value MTV in FIG. 3).

[0041] The plasma processing method using the plasma processing apparatus 100 can be summarized as follows: In other words, 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 arranged inside a processing chamber 101 arranged inside a vacuum vessel 108, in which plasma is generated, and the semiconductor wafer 115 is processed using plasma while high frequency power is supplied from a high frequency power source 104 to an electrode (116) arranged inside the sample stage 115 during processing of the semiconductor wafer.

[0042] The high frequency power is configured to be supplied from high frequency power supply 104 in a cycle of a large amplitude period PA and a small amplitude period PB every predetermined cycle T1. Furthermore, the high frequency power is adjusted using information (information on the detection result of the traveling wave by the directional coupler) indicating the magnitude of the high frequency power detected during a period (corresponding to the period indicated as FB control FBC in FIG. 3) after a predetermined time (corresponding to mask time value MTV in FIG. 3) has elapsed after the start of either the large amplitude period PA or the small amplitude period PB of the high frequency power (corresponding to the large amplitude period PA in FIG. 3), and the length of the predetermined time (corresponding to mask time value MTV in FIG. 3) is variably adjusted.

[0043] FIG. 5 is an example of a table illustrating the selection of the mask time value of the high-frequency power supply 104 by the equipment CPU 107. Each parameter in FIG. 5 (parameter 1 (PAR1), parameter 2 (PAR2), parameter 3 (PAR3), and parameter 4 (PAR41)) is determined based on the conditions actually used in the etching process. The optimal mask time value MTV varies depending on the maximum output power of the installed high-frequency power supply 104. Therefore, when the high-frequency power supply 104 is installed in the etching equipment 100, the optimal mask time value MTV for each combination of parameters such as TM duty, output power range, gas flow rate, and processing pressure range is measured in advance and input into the equipment CPU 107 as a table and stored before the flowchart for automatic selection of the mask time value MTV of the present disclosure is implemented. The preliminary measurement conditions will be described using FIG. 5 as an example. Parameters 1-4 used in the etching process are, for example, as follows:

[0044] Parameter 1 (PAR1): TM Duty = (PA / T1) x 100%): 1) 50% or more, 2) 50% or less (minimum pulse width).

[0045] Parameter 2 (PAR2): Processing pressure range during etching process in the processing chamber 101 (processing pressure): 1) 5mTorr or less, 2) above 5mTorr and below 10mTorr, 3) above 10mTorr and below 15mTorr, 4) Above 15mTorr and below 20mTorr, 5) Above 20mTorr and below 25mTorr, ..., N) Above 45mTorr and below 50mTorr.

[0046] Parameter 3 (PAR3): Output power range (power setting) of the high frequency power PoutRF output by the high frequency power supply 104: 1) 1000W or less, 2) Above 1000W and below 2000W, 3) Above 2000W and below 4000W.

[0047] Parameter 4 (PAR4): Argon (Ar) gas flow rate during etching process: 1) 200ml / min or less, 2) Above 200 ml / min.

[0048] The mask time value MTV is changed in 10% increments under the conditions of each combination of parameters 1-4. The mask time value MTV when the closest actual value is output to the output power range set by parameter 3 (PAR3) is measured and entered into the table in Figure 5. By using the entered table in Figure 5, it is possible to automatically select the mask time value MTV.

[0049] By measuring the table in FIG. 5 in advance and storing it in the device CPU 107, FB control can be performed without being affected by parameters 1-4 (TM Duty, output power range, gas flow rate, processing pressure range), and the errors between the output set value and the actual output value of the high frequency power supply 104 can be kept within a predetermined tolerance range.

[0050] During operation of step S301, the equipment CPU 107 reads the data in the table of FIG. 5 and compares it with the input etching parameters 1-4 of TM Duty, output power range, gas flow rate, and processing pressure range to automatically select the mask time value MTV.

[0051] 5, which shows the relationship between a predetermined period (mask time value MTV) and at least one value selected from a plurality of parameters including the pressure within the processing chamber 101 during semiconductor wafer processing, the magnitude of the high-frequency power (PoutRF) output from the high-frequency power supply 104, and the ratio (here, TM Duty) of the high-amplitude period PA or the low-amplitude period PB in the cycle T1, is used to adjust the length of the predetermined time (mask time value MTV) according to the processing conditions of the semiconductor wafer. Furthermore, in this example, the mask time value MTV can be automatically selected. Furthermore, in the plurality of steps constituting the processing of one semiconductor wafer performed in the processing chamber 101, the length of the predetermined time (mask time value MTV) is adjusted according to the processing conditions for each step.

[0052] In addition to the above parameters 1-4, Figure 5 is configured to allow the addition or deletion of parameters such as the power of the magnetron power supply 102, the output frequency of the high-frequency power supply 104, the TM frequency set in 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.

[0053] In addition, the data in the table of FIG. 5 can be stored not only in the device CPU 107, but also directly input to the computer PC mounted on the device CPU 107, and can be reflected at any time by communication between the computer PC and the device CPU 107.

[0054] By the above series of operations, the apparatus CPU 107 can transmit the optimum mask time value MTV to be set to the high frequency power supply 104 via the control unit 106 for each of a plurality of etching steps.

[0055] <Effects of the Example> The embodiment has the following advantages.

[0056] 6A, 6B, 7A, and 7B are conceptual diagrams of waveforms output from high-frequency power supply 104. These waveforms are assumed examples, and the waveforms shown in FIGS. 6A, 6B, 7A, and 7B are not necessarily output from high-frequency power supply 104.

[0057] The optimum value of the timing of the feedback control during the power output from the high frequency power supply 104 changes depending on the influence of the high frequency output power, the ON time, and the plasma load.

[0058] 6A and 6B are conceptual diagrams showing a fixed mask time value according to a comparative example, and FIGS. 7A and 7B are conceptual diagrams showing a selected (variable) mask time value according to an embodiment.

[0059] 6A and 6B 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, ON time, and plasma load. As mentioned above, if the FB region is controlled at a constant value, the FB control will not be performed at an optimal value, and a waveform that deviates from the output set value of the RF bias power supply, which is the period when FB control should be stopped, will be used for FB control. As a result, there is a risk that the actual output power output from the high-frequency power supply 104 will differ from the output set value.

[0060] 6A and 6B, by selecting an appropriate mask time value MTV when the output waveform of the high frequency power supply 104 changes depending on the TM duty, output power range, and processing pressure range, the timing when the output set value and the actual output power value approach each other can be used for the feedback control FBC. As a result, the high frequency power supply 104 can recognize a value close to the output set value and perform the output operation of the next waveform.

[0061] As described above, by selecting the mask time value MTV from the etching parameters of the TM Duty, output power range, and processing pressure range, it is possible to reduce the difference between the output setting value and the actual output of the high frequency power supply 104.

[0062] In the present disclosure, the mask time value MTV of the high frequency power supply 104 is configured to be variably set for each processing step, and at the start of the processing step for the wafer 115, the mask time value MTV is variably set according to the conditions related to the output of the high frequency power supply 104 and the plasma load set in the recipe. Also, previously acquired data indicating the relationship between the previously acquired conditions related to the output of the high frequency power supply 104 and the plasma load and the mask time value MTV is used as a parameter table (see FIG. 5), and an appropriate mask time value MTV is automatically set.

[0063] This allows the optimal mask time value MTV to be set in the high frequency power supply 104 for each processing step of the wafer 115. This makes it possible to achieve stable plasma processing (etching processing) and also improve the yield of the plasma processing (etching processing).

[0064] As described above, the problem that the dimensions of the shape obtained as a result of wafer processing deviate from the intended dimensions and the yield of processing by the plasma processing apparatus is reduced is solved. [Explanation of symbols]

[0065] 100: Plasma etching equipment (plasma processing equipment) 101: Processing room 104: High frequency power supply 106: Control unit 107: Device CPU 108: Vacuum container 115: Semiconductor wafer (sample) 116: Electrode for placing sample (sample stage) 120: Control device.

Claims

1. A plasma processing apparatus comprising: a processing chamber arranged inside a vacuum vessel and in which plasma is generated; a sample stage arranged inside the processing chamber and on which a semiconductor wafer to be processed using the plasma is placed; an electrode arranged inside the sample stage and to which high frequency power is supplied during processing of the semiconductor wafer; and a control device for adjusting the supply of the high frequency power from a high frequency power source, The high frequency power is supplied from the high frequency power source during processing of the semiconductor wafer, with the amplitude or output thereof being set to a plurality of different values, each of which is supplied for a predetermined period of time, The control device adjusts the supply of high-frequency power using information indicating the magnitude of the high-frequency power detected during a period in which the high-frequency power is set to another value after a predetermined time has elapsed since the high-frequency power was changed from one of the plurality of different values ​​to another value, and the plasma processing apparatus has the function of variably adjusting the length of the predetermined time in accordance with the value of at least one parameter included in the conditions for processing the semiconductor wafer.

2. 2. The plasma processing apparatus according to claim 1, The at least one parameter includes a flow rate of a gas supplied to the processing chamber during the processing.

3. 3. The plasma processing apparatus according to claim 1, The at least one parameter includes a pressure in the processing chamber during processing of the semiconductor wafer, or a proportion of the predetermined period during which the magnitude or amplitude of the high frequency power output from the high frequency power source during processing is set to at least one value among the plurality of different values.

4. 3. The plasma processing apparatus according to claim 1, The plasma processing apparatus adjusts the length of the predetermined time period using data indicating the relationship between the value of the at least one parameter and the predetermined time period.

5. 3. The plasma processing apparatus according to claim 1, The high frequency power is supplied in such a manner that a period in which the amplitude is large and a period in which the amplitude is small or zero or a period that is small enough to be regarded as such are repeated for each period.

6. 3. The plasma processing apparatus according to claim 1, A plasma processing apparatus in which the length of the predetermined time is adjusted in accordance with processing conditions of a plurality of steps constituting processing of one of the semiconductor wafers performed in the processing chamber.

7. 1. A plasma processing method comprising: placing a semiconductor wafer to be processed on a sample stage disposed in a processing chamber disposed inside a vacuum vessel in which plasma is generated; and processing the semiconductor wafer using the plasma while supplying high frequency power from a high frequency power source to an electrode disposed inside the sample stage during processing of the semiconductor wafer, the method comprising: the high frequency power is supplied from the high frequency power source during processing of the semiconductor wafer with the amplitude or output thereof set to a plurality of different values, each of which is for a predetermined period of time, and is adjusted using information indicating the magnitude of the high frequency power detected during a period in which the high frequency power is set to another value after a predetermined time has elapsed since the high frequency power was changed from one of the plurality of different values ​​to another value, A plasma processing method, wherein the length of the predetermined time is variably adjusted depending on the value of at least one parameter included in the processing conditions of the semiconductor wafer.

8. 8. The plasma processing method according to claim 7, The plasma processing method, wherein the at least one parameter includes a flow rate of a gas supplied to the processing chamber during the processing.

9. 9. The plasma processing method according to claim 7, further comprising: A plasma processing method, wherein the at least one parameter includes a pressure in the processing chamber during processing of the semiconductor wafer, or a proportion of the predetermined period during which the magnitude or amplitude of the high frequency power output from the high frequency power source during the processing is set to at least one value among the plurality of different values.

10. 9. The plasma processing method according to claim 7, further comprising: The plasma processing method, wherein the length of the predetermined time is adjusted using data indicating a relationship between the value of the at least one parameter and the predetermined time period.

11. 9. The plasma processing method according to claim 7, further comprising: The plasma processing method in which the high frequency power is supplied in each cycle by repeating a period in which the amplitude is large and a period in which the amplitude is small or zero or a period that is small enough to be regarded as such.

12. 9. The plasma processing method according to claim 7, further comprising: A plasma processing method, wherein the length of the predetermined time is adjusted in accordance with processing conditions of a plurality of steps constituting processing of one of the semiconductor wafers performed in the processing chamber.

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