Plasma processing apparatus and end point detection method

Abstract

The chamber is internally provided with a mounting table on which a substrate can be mounted. The electrode is disposed within the chamber. The measuring unit is provided to the electrode or a wiring connected to the electrode, and measures either a voltage or a current. The gas supply unit supplies a gas for plasma formation into the chamber. The power supply supplies, to the chamber, periodic electric power that causes the gas supplied into the chamber to become plasma, the electric power level being changed for each period in one period. The detection unit detects an end point of the first etching on the basis of at least one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit at a first timing within one cycle of the periodic electric power. The detection unit detects an end point of the second etching on the basis of at least one of the voltage, the current, and the phase difference between the voltage and the current measured by the measurement unit at a second timing different from the first timing in the one cycle.

Description

Technical Field

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

[0002] Patent Document 1 discloses a technique for detecting an end point of etching based on a signal measured by a VI probe during plasma etching.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent Application Publication No. 2005 / 0217795 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] The present invention provides a technology for detecting an etching endpoint with high accuracy.

[0008] Technical means for solving technical problems

[0009] A plasma processing device according to one embodiment of the present invention comprises a chamber, an electrode, a measuring unit, a gas supply unit, a power supply, and a detection unit. The chamber is provided with a mounting table capable of mounting a substrate. The electrode is arranged in the chamber. The measuring unit is provided on the electrode or the wiring connected to the electrode, and is used to measure any one of voltage and current. The gas supply unit supplies gas for plasma formation into the chamber. The power supply supplies periodic electric power to the chamber, and the periodic electric power is electric power for plasma formation of the gas supplied into the chamber, and the electric power level is changed in each period within one cycle. The detection unit detects the end point of the first etching based on at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring unit at a first moment within one cycle of the periodic electric power. The detection unit detects the end point of the second etching based on at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring unit at a second moment different from the first moment within one cycle.

[0010] Effects of the Invention

[0011] According to the present invention, the end point of etching can be detected with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FIG. 1 is a diagram showing an example of a schematic configuration of a plasma processing system according to an embodiment.

[0013] Figure 2 This is a block diagram showing an example of a schematic configuration of a control unit according to an embodiment.

[0014] Figure 3A This is a diagram showing an example of changes in periodic electric power (ie, electric power) supplied from a power supply according to an embodiment.

[0015] Figure 3B This is a diagram showing an example of changes in periodic electric power supplied from a power supply according to an embodiment.

[0016] Figure 4 It is a diagram for explaining detection of an etching endpoint according to an embodiment.

[0017] Figure 5 It is a diagram for explaining detection of a conventional etching endpoint.

[0018] Figure 6 This is a diagram showing an example of a schematic structure of a substrate to be etched according to an embodiment.

[0019] Figure 7 This is a diagram showing an example of periodic electric power supplied from a power supply according to an embodiment.

[0020] Figure 8 FIG. 1 is a diagram showing an example of a schematic structure of an etched substrate W according to an embodiment.

[0021] Fig. 9 This is a diagram schematically showing changes in a signal measured by a measuring unit according to the embodiment.

[0022] Fig.10 This is a diagram for explaining an example of detection of the end point of etching of the first film and the second film according to the embodiment.

[0023] Fig.11A This is a diagram schematically showing an example of changes in periodic electric power supplied from a power supply according to an embodiment.

[0024] Fig. 11B This is a diagram schematically showing an example of changes in periodic electric power supplied from a power supply according to an embodiment.

[0025] Fig.12 This is a diagram for explaining an example of detecting an end point of etching according to an embodiment.

[0026] Fig.13 This is a diagram for explaining an example of detecting an end point of etching according to an embodiment.

[0027] Fig.14 This is a diagram for explaining an example of the processing procedure of the endpoint detection method according to the embodiment. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the plasma processing apparatus and the endpoint detection method described in the present application will be described in detail with reference to the accompanying drawings. In addition, the plasma processing apparatus and the endpoint detection method described in the specification are not limited to the embodiments.

[0029] In plasma etching, in order to prevent excessive etching and suppress changes in pattern shape, a method of stopping the etching process by detecting the end point of etching in real time is applied. As an existing method for detecting the end point of etching, for example, there is a method of using an OES (Optical Emission Sensor) to detect the end point of etching based on changes in the luminous intensity of the plasma during etching. In addition, there is a method of detecting the end point of etching based on a signal measured by a VI probe during plasma etching. For example, the end point of etching is detected based on the moving average of the signal continuously measured by the VI probe.

[0030] In addition, multi-colored etching, which etches three or more types of films at once, is studied. In multi-colored etching, periodic electric power whose electric power level is changed in each period within one cycle is supplied to a chamber to generate plasma and perform etching.

[0031] However, in the conventional method of detecting the end point of etching, when the electric power fluctuates periodically, the end point of etching cannot be detected with high accuracy. Therefore, a technology for detecting the end point of etching with high accuracy is desired.

[0032] [Implementation Method]

[0033] [Device structure]

[0034] An example of a plasma processing apparatus of the present invention will be described. In the embodiments described below, a plasma processing system including the plasma processing apparatus of the present invention as a system configuration will be described as an example. Figure 1 FIG. 1 is a diagram showing an example of a schematic configuration of a plasma processing system according to an embodiment.

[0035] Hereinafter, a configuration example of a plasma processing system will be described. Figure 1 It is a diagram for explaining a configuration example of a capacitive coupling type plasma processing apparatus.

[0036] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a control unit 100. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. In addition, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to be able to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a showerhead 13. The substrate support unit 11 is arranged in the plasma processing chamber 10. The showerhead 13 is arranged above the substrate support unit 11. In one embodiment, the showerhead 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. In addition, the plasma processing chamber 10 has: at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s; and at least one gas exhaust port for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10 .

[0037] The substrate support portion 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 when viewed from above. The substrate W is arranged on the central region 111a of the main body 111, and the ring assembly 112 is arranged on the annular region 111b of the main body 111 in a manner of surrounding the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0038] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive component. The conductive component of the base 1110 can act (function) as a lower electrode. The electrostatic chuck 1111 is arranged on the base 1110. The electrostatic chuck 1111 includes a ceramic component 1111a and an electrostatic electrode 1111b arranged in the ceramic component 1111a. The ceramic component 1111a has a central area 111a. In one embodiment, the ceramic component 1111a also has an annular area 111b. Among them, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck and an annular insulating component, may also have an annular area 111b. In this case, the ring assembly 112 can be arranged on the annular electrostatic chuck or the annular insulating component, or on both the electrostatic chuck 1111 and the annular insulating component. In addition, at least one RF / DC electrode coupled to the RF (Radio Frequency) power supply 31 and / or the DC (Direct Current) power supply 32 described later may also be arranged in the ceramic component 1111a. In this case, at least one RF / DC electrode functions as a lower electrode. In the case where the bias RF signal and / or DC signal described later is supplied to at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. In addition, the conductive component of the base 1110 and at least one RF / DC electrode may also function as multiple lower electrodes. In addition, the electrostatic electrode 1111b may be used as a lower electrode. Therefore, the substrate support portion 11 includes at least one lower electrode.

[0039] The ring assembly 112 includes one or more ring-shaped components. In one embodiment, the one or more ring-shaped components include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0040] In addition, the substrate support portion 11 may also include a temperature adjustment module, which is configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112 and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path 1110a or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are arranged in the ceramic part 1111a of the electrostatic chuck 1111. In addition, the substrate support portion 11 may also include a heat transfer gas supply portion, which is configured to supply a heat transfer gas to the gap between the back side of the substrate W and the central area 111a.

[0041] The shower head 13 is configured to be able to introduce at least one processing gas from the gas supply part 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c through the gas diffusion chamber 13b. In addition, the shower head 13 includes at least one upper electrode. Among them, in addition to the shower head 13, the gas introduction part may also include one or more side gas injection parts (SGI: Side Gas Injector) installed in one or more openings formed in the side wall 10a.

[0042] The gas supply unit 20 may also include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may also include a mass flow controller or a pressure-controlled flow controller. In addition, the gas supply unit 20 may also include one or more flow modulation devices for modulating or pulsing the flow of at least one processing gas.

[0043] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. Thus, plasma can be formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of a plasma generating unit, which is configured to generate plasma from one or more processing gases in the plasma processing chamber 10. In addition, by supplying a bias RF signal to at least one lower electrode, a bias potential can be generated on the substrate W, and ion components in the formed plasma can be introduced into the substrate W.

[0044] In one embodiment, the RF power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit, and is capable of generating a source RF signal (source RF electric power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generator 31a may also be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0045] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit, and is capable of generating a bias RF signal (bias RF electric power). The frequency of the bias RF signal may be the same as or different from the frequency of the generating source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the generating source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100kHz to 60MHz. In one embodiment, the second RF generating unit 31b may also be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In addition, in each embodiment, at least one of the generating source RF signal and the bias RF signal may also be pulsed.

[0046] For example, the first RF generating unit 31a is electrically connected to the conductive component of the shower head 13 via a conductive portion 33a such as wiring. An impedance matching circuit 34a is provided in the conductive portion 33a. The impedance matching circuit 34a matches the output impedance of the first RF generating unit 31a with the input impedance of the load side (the shower head 13 side). The first RF generating unit 31a supplies the first electric power of the first frequency for generating plasma to the conductive component of the shower head 13. For example, the first RF generating unit 31a supplies the above-mentioned generation source RF signal as the first electric power to the conductive component of the shower head 13 via the conductive portion 33a and the impedance matching circuit 34a. The generation source RF signal is, for example, 60 MHz. The conductive component of the shower head 13 acts as an electrode. By supplying the generation source RF signal, a high-density plasma can be generated in the plasma processing chamber 10.

[0047] In addition, for example, the second RF generating unit 31b is electrically connected to the conductive component of the base 1110 of the substrate supporting unit 11 via the conductive portion 33b such as wiring. An impedance matching circuit 34b is provided in the conductive portion 33b. The impedance matching circuit 34b matches the output impedance of the second RF generating unit 31b with the input impedance of the load side (the substrate supporting unit 11 side). The second RF generating unit 31b supplies the second electric power of the second frequency lower than the first frequency for introducing the ion components in the plasma into the substrate W to the conductive component of the substrate supporting unit 11. For example, the second RF generating unit 31b supplies the above-mentioned bias RF signal as the second electric power to the conductive component of the substrate supporting unit 11 via the conductive portion 33b and the impedance matching circuit 34b. The bias RF signal is, for example, 40MHz. The conductive component of the substrate supporting unit 11 functions as an electrode. By supplying the bias RF signal, the ion components in the plasma generated in the plasma processing chamber 10 are introduced (attracted) to the substrate W.

[0048] The plasma processing apparatus 1 is provided with a measuring unit 35 for measuring any one of voltage and current at an electrode arranged in the plasma processing chamber 10 or a wiring connected to the electrode. The plasma processing apparatus 1 of this embodiment is provided with a measuring unit 35a at a conductive portion 33a connected to a conductive member of the shower head 13. In addition, the plasma processing apparatus 1 of this embodiment is provided with a measuring unit 35b at a conductive portion 33b connected to a conductive member of the substrate support portion 11. The measuring units 35a and 35b are configured to include probes for detecting current and voltage. The measuring units 35a and 35b measure voltage and current. The measuring unit 35a measures the voltage and current flowing through the conductive portion 33a generating the source RF signal. The measuring unit 35a outputs a signal indicating the measured voltage and current to the control unit 100. The measuring unit 35b measures the voltage and current of the conductive portion 33b through which the bias RF signal flows. The measuring unit 35b outputs a signal indicating the measured voltage and current to the control unit 100.

[0049] In addition, the power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is connected to at least one lower electrode and is configured to generate a first DC signal. The generated first bias DC signal is applied to at least one lower electrode. In one embodiment, the second DC generating unit 32b is connected to at least one upper electrode and is configured to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0050] In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulse may have a pulse waveform of a rectangle, a trapezoid, a triangle, or a combination thereof. In one embodiment, a waveform generator for generating a sequence of voltage pulses from a DC signal is connected between the first DC generator 32a and at least one lower electrode. Therefore, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. In the case where the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulse may have a positive polarity or a negative polarity. In addition, the sequence of voltage pulses may also include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses within one cycle. In addition, in addition to the RF power supply 31, the first and second DC generators 32a and 32b may be provided, and the first DC generator 32a may also be provided instead of the second RF generator 31b.

[0051] The exhaust system 40 can be connected to the gas exhaust port 10e provided at the bottom of the plasma processing chamber 10, for example. The exhaust system 40 can also include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s can be adjusted by the pressure regulating valve. The vacuum pump can also include a turbomolecular pump, a dry pump, or a combination thereof.

[0052] The operation of the plasma processing apparatus 1 configured as described above is comprehensively controlled by the control unit 100 .

[0053] Figure 2 This is a block diagram showing an example of a schematic configuration of the control unit 100 according to the embodiment.

[0054] The control unit 100 is, for example, a computer, and controls each unit of the plasma processing apparatus 1. The operation of the plasma processing apparatus 1 is comprehensively controlled by the control unit 100. The control unit 100 controls the plasma processing apparatus 1 to execute various steps described in this specification. The control unit 100 is provided with an external interface 101, a process controller 102, a user interface 103, and a storage unit 104.

[0055] The external interface 101 can communicate with each part of the plasma processing apparatus 1 and input and output various data. A signal indicating the voltage and current measured by the measuring unit 35 is input to the external interface 101. In this embodiment, a signal indicating the voltage and current measured by the measuring units 35a and 35b is input to the external interface 101.

[0056] The process controller 102 includes a CPU (Central Processing Unit) and controls various components of the plasma processing apparatus 1 .

[0057] The user interface 103 is composed of a keyboard for a process manager to input commands for managing the plasma processing apparatus 1 , a display for visually displaying the operating status of the plasma processing apparatus 1 , and the like.

[0058] The storage unit 104 stores control programs (software) for implementing various processes performed by the plasma processing apparatus 1 under the control of the process controller 102, and recipes storing processing condition data, etc. In addition, the control program and recipe may be stored in a computer recording medium (such as a hard disk, an optical disk such as a DVD, a floppy disk, a semiconductor memory, etc.) that can be read by a computer, and the control program and recipe may be used online by being transmitted from other devices at any time, such as via a dedicated line.

[0059] The process controller 102 has an internal memory for storing programs and data, reads out the control program stored in the storage unit 104, and executes the processing of the read control program. The process controller 102 acts as various processing units by operating the control program. For example, the process controller 102 has the functions of a plasma control unit 102a and a detection unit 102b. In addition, in this embodiment, the case where the process controller 102 has the functions of a plasma control unit 102a and a detection unit 102b is used as an example for description. However, the functions of the plasma control unit 102a and the detection unit 102b can also be implemented by multiple controllers in a distributed manner.

[0060] The plasma control unit 102a controls the plasma processing. For example, the plasma control unit 102a controls the exhaust system 40 to exhaust the plasma processing chamber 10 to a predetermined vacuum level. The plasma control unit 102a controls the gas supply unit 20 to introduce the etching processing gas from the gas supply unit 20 into the plasma processing space 10s. The plasma control unit 102a controls the power supply 30 to supply the generation source RF signal and the bias RF signal from the first RF generation unit 31a and the second RF generation unit 31b in coordination with the introduction of the processing gas, thereby generating plasma in the plasma processing chamber 10.

[0061] The plasma processing apparatus 1 of the present embodiment performs multi-color etching. The plasma control unit 102a controls the power supply 30, and supplies electric power from the power supply 30 to plasmatize the processing gas for etching supplied to the plasma processing chamber 10. For example, the plasma control unit 102a controls so that the power supply 30 supplies periodic electric power to the plasma processing chamber 10, the electric power level of which is changed in each period within one cycle. The RF power supply 31 supplies periodic electric power that changes the electric power level of at least one of the generation source RF signal and the bias RF signal in each period within one cycle. For example, the plasma control unit 102a controls the RF power supply 31, and supplies the periodic generation source RF signal and the bias RF signal, the electric power level of which is changed in each period within one cycle, from the first RF generation unit 31a and the second RF generation unit 31b, respectively. The frequency of the generation source RF signal and the bias RF signal is, for example, 100 Hz to 10 kHz. Hereinafter, of the generation source RF signal and the bias RF signal, the generation source RF signal having a higher frequency is also referred to as HF (High Frequency), and the bias RF signal having a lower frequency is also referred to as LF (Low Frequency).

[0062] In multi-color etching, the electric power level is controlled to be suitable for etching the target film in each period within one cycle. In multi-color etching, the target film to be etched mainly in the period within one cycle can be determined, and the electric power level is controlled in accordance with the target film in each period within one cycle, thereby obtaining the desired etching characteristics.

[0063] Figure 3A and Figure 3B 1 is a diagram showing an example of a change in the periodic electric power supplied from the power supply 30 according to the embodiment. Figure 3A and Figure 3B 1 shows an example of the change in the power level in each period within one cycle of the periodic power supplied from the power supply 30. "HF" represents the change in the power of the source RF signal by amplitude. "LF" represents the change in the power of the bias RF signal by amplitude.

[0064] exist Figure 3A In the example, one cycle is divided into periods T11 to T13. The source RF signal is HPL11 with high power in period T11, and HPL12 with lower power than HPL11 in periods T12 and T13. The power of the bias RF signal is zero in periods T11 and T12, and LPL11 with high power in period T13.

[0065] exist Figure 3BIn the example, one cycle is divided into periods T21 to T24. The power of the source RF signal is gradually reduced from a large HPL21 to a small HPL24 during the period T21 to T24. The power of the bias RF signal is gradually increased from a small LPL21 to a large LPL24 during the period T21 to T24.

[0066] return Figure 2 . The detection unit 102b detects the end point of the plasma treatment based on the voltage and current of the signal input from the measuring unit 35. For example, the detection unit 102b detects the end point of the plasma treatment based on the change of at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring units 35a and 35b at a time (timing) synchronized with the cycle of the periodic electric power supplied from the power supply 30 to the plasma processing chamber 10. In the present embodiment, the detection unit 102b detects the end point of etching based on the change of at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring units 35a and 35b at a time synchronized with the cycle of the electric power. The detection unit 102b detects the end point of etching based on the change of at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring units 35a and 35b at the time when the combination of the supplied generation source RF signal and the bias RF signal contributes most to etching and the selectivity. For example, in the present embodiment, the period during which the bias RF signal is supplied contributes most to etching and the selectivity. The detection unit 102 b detects the end point of etching based on a change in at least any one of the voltage, the current, and the phase difference between the voltage and the current measured by the measurement unit 35 while the bias RF signal is being supplied.

[0067] The plasma control unit 102a controls the plasma processing based on the detection result of the detection unit 102b. For example, the plasma control unit 102a controls the electric power level according to the cycle of the electric power and each period of one cycle based on the detection result of the detection unit 102b. For example, the plasma control unit 102a shortens or deletes the period corresponding to the etching target film in which the end point of etching is detected in one cycle of the electric power. Alternatively, the plasma control unit 102a allocates the period corresponding to the etching target film in which the end point of etching is detected in one cycle of the electric power to the etching period of other etching target films. The plasma control unit 102a ends the plasma etching when the etching end point is detected for all etching target films by the detection unit 102b.

[0068] Here, an example of etching in which the power level is changed for each period in one cycle is described. Figure 4 It is a diagram for explaining an example of etching according to the embodiment. Figure 4This shows the case where the generation source RF signal and the bias RF signal are turned on and off in one cycle, respectively, and the electric power level is changed in each period in one cycle to generate plasma in a pulsed supply. Figure 4 In the "On" period, the source RF signal and the bias RF signal are supplied. "HF" indicates the period when the source RF signal is supplied. "LF" indicates the period when the bias RF signal is supplied. The source RF signal and the bias RF signal are supplied during the On period. Figure 4 In the example, the source RF signal and the bias RF signal are generated and supplied in pulses without overlapping the periods. Figure 4 In the process, the frequency of the pulses of the source RF signal and the bias RF signal on and off is set to 1 kHz, and the source RF signal and the bias RF signal are turned on and off at a cycle of 1 ms to perform etching.

[0069] exist Figure 4 The following characteristics of free radicals (Radical) and ions and electrons (Ion / Electron) contained in the plasma are shown in . The following of free radicals to the switching on (On) and off (Off) of high-frequency electric power is more than 1ms. Therefore, in one cycle of switching on and off, free radicals generated at different electric power levels are mixed. For example, during the period when LF is turned on, free radicals generated during the previous period when HF is turned on and free radicals generated during the period when LF is turned on are mixed. Therefore, when the end point of etching is detected by taking free radicals such as byproducts (by products) generated at a specific electric power level as the object, the free radicals generated at other electric power levels and their tails near the signal wavelength become noise. For example, during the period when LF is turned on, free radicals generated during the previous period when HF is turned on become noise.

[0070] On the other hand, the time it takes for ions and electrons to follow the turning on and off of high-frequency electric power is 0.1 ms or less. Therefore, in etching using RF pulses of 100 Hz to 10 kHz, no interference due to different electric power levels occurs.

[0071] Here, for comparison, detection of the endpoint of etching using conventional OES will be described. Figure 51 is a diagram for explaining the detection of the conventional end point of etching. When the electric power level is changed in each period within one cycle, free radicals generated at different electric power levels as described above are mixed in the plasma. Therefore, even if one wants to detect the luminous intensity of the plasma during etching by OES and detect the end point of etching based on the change in the detected luminous intensity, the end point of etching cannot be detected with high accuracy. For example, even if one wants to detect the end point of etching based on the change in the luminous intensity of the plasma during the LF on period, the luminous intensity of the free radicals during the HF on period is mixed during the LF on period, so the end point of etching cannot be detected with high accuracy.

[0072] Next, an example of detecting the end point of etching according to the present embodiment will be described. First, an example of a substrate W to be etched will be described. Figure 6 FIG. 1 is a diagram showing an example of a schematic structure of a substrate W to be etched according to the embodiment. Figure 6 (B) is a top view of the substrate W as viewed from above. Figure 6 (A) is a cross-sectional view showing a cross section of the substrate W along the line A shown in (B).

[0073] The substrate W has a plurality of linear structures 205 formed in parallel on a base film 200. A first film 201 is formed on the upper portion of each structure 205. In addition, a second film 202 is formed between each structure 205 to a position higher than the upper surface of the structure 205. In addition, a third film 203 is formed on a portion between the structures 205. The first film 201 and the second film 202 are respectively etching target films. For example, one of the first film 201 and the second film 202 is a nitride film and the other is an oxide film. Depending on the level of electric power supplied during etching, the etching rate of the first film 201 and the second film 202 is dominant. The third film 203 is, for example, a mask film.

[0074] For such a substrate W, the first film 201 and the second film 202 are etched using the third film 203 as a mask. For example, the plasma processing apparatus 1 supplies a process gas for etching into the plasma processing chamber 10, and supplies a periodic electric power whose electric power level is changed in each period within one cycle from the power supply 30 to the plasma processing chamber 10, thereby etching the first film 201 and the second film 202. For example, the power supply 30 supplies a DC voltage whose voltage level is changed in each period within one cycle from the first DC generating unit 32a to the lower electrode included in the substrate supporting unit 11. In addition, the power supply 30 supplies a source RF signal whose electric power level is changed in each period within one cycle from the first RF generating unit 31a to the conductive member of the shower head 13 via the conductive unit 33a. In addition, the power supply 30 supplies a bias RF signal whose electric power level is changed in each period within one cycle from the second RF generating unit 31b to the conductive member of the susceptor 1110 of the substrate supporting unit 11 via the conductive unit 33b.

[0075] Figure 7 FIG. 1 is a diagram schematically showing an example of a change in the periodic electric power supplied from the power supply 30 according to the embodiment. Figure 7 The figure shows the change in one cycle of the periodic electric power supplied to the plasma processing chamber 10. "DC voltage" shows the change in the DC voltage applied to the lower electrode included in the substrate support 11. "HF" shows the change in the electric power of the generated source RF signal. "LF" shows the change in the electric power of the bias RF signal. Figure 7 In the embodiment, one cycle of the periodic electric power is divided into periods T31 to T34. The DC voltage is a high voltage during periods T31 and T32, and a low voltage during periods T33 and T34. HF is a high power during period T31, a medium power during period T32, and a low power during periods T33 and T34. LF is not supplied during periods T31 and T32, a low power during period T13, and a high power during period T34. Depending on the electric power of the bias RF signal, the etching rate of the first film 201 and the second film 202 that is dominant changes. For example, in period T11 within one cycle, film 1 (Depo1) is formed on substrate W. In period T12, film 2 (Depo2) is formed on substrate W. In period T13, etching (Etch1) of the first film 201 of substrate W is performed. Period T13 is the period that contributes most to the etching of the first film 201 and the selectivity. In the period T14, etching (Etch2) of the second film 202 of the substrate W is performed. The period T14 is the period that contributes most to the etching of the second film 202 and the selectivity.

[0076] Figure 8 FIG. 1 is a diagram showing an example of a schematic structure of a substrate W after etching according to an embodiment. Figure 8(B) is a top view of the substrate W as viewed from above. Figure 8 (A) is a cross-sectional view showing a cross section of the substrate W along the line A shown in (B). Figure 8 Yes Figure 6 The first film 201 and the second film 202 of the substrate W are shown as a result of etching. By etching, the first film 201 and the second film 202 on the substrate W are removed.

[0077] The measuring unit 35a measures the voltage and current flowing through the conductive unit 33a generating the source RF signal. The measuring unit 35b measures the voltage and current flowing through the conductive unit 33b through which the bias RF signal flows. The measuring units 35a and 35b output signals indicating the measured voltage and current to the control unit 100.

[0078] Fig. 9 : is a diagram schematically showing changes in signals measured by the measuring units 35a and 35b according to the embodiment. Fig. 9 1 schematically shows the change of the signal (VI signal) measured by the measuring parts 35a and 35b during the period T31 to T34 in one cycle between the start of etching and the end of etching (Etch1) of the first film 201. VI (HF) schematically shows the change of the signal measured by the measuring part 35a provided in the conductive part 33a where the source RF signal flows. VI (LF) schematically shows the change of the signal measured by the measuring part 35b provided in the conductive part 33b where the bias RF signal flows.

[0079] During etching, the components of the etched first film 201 and second film 202 are continuously released into the plasma. When the etching of the first film 201 and second film 202 is completed, the release of the components of the first film 201 and second film 202 disappears, and the characteristics of the plasma change. As a result, the signal (VI signal) measured by the measuring units 35a and 35b changes. For example, Fig. 9 As shown, VI(LF) changes significantly during period T33 due to the completion of etching of the first film 201. Therefore, by measuring the change in at least one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit 35b during period T33, the end point of etching of the first film 201 can be detected.

[0080] The detection unit 102b detects the status of the plasma processing based on the voltage and current of the signal input from the measurement units 35a and 35b. For example, the detection unit 102b detects the end point of the plasma processing based on the voltage and current of the signal input from the measurement units 35a and 35b. For example, the detection unit 102b detects the end point of the plasma processing based on the change of at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measurement units 35a and 35b at the time synchronized with the cycle of the periodic electric power supplied from the power supply 30 to the plasma processing chamber 10. For example, the detection unit 102b detects the end point of the etching of the first film 201 based on the change of the signal measured by the measurement unit 35b at the time of the period T33 when the combination of the source RF signal and the bias RF signal contributes most to the etching of the first film 201 and the selectivity. For example, the detection unit 102b monitors the voltage, current, and phase difference between the voltage and the current measured in the period T33 in real time, and detects the moment of intentional change as the end point of the etching of the first film 201. In addition, the detection unit 102b detects the end point of etching of the second film 202 based on the change of the signal measured by the measurement unit 35b at the time of the period T34 when the combination of the source RF signal and the bias RF signal contributes most to the etching of the second film 202 and the selectivity. For example, the detection unit 102b monitors the voltage, current, and phase difference between the voltage and current measured during the period T34 in real time, and detects the moment of intentional change as the end point of etching of the second film 202. The detection unit 102b may also apply a common mathematical method for reducing noise, such as moving average and time differentiation, in the data processing for detecting the end point. The measurement unit 35 may also extract a signal of a specific frequency by passing the voltage and current signals through a frequency filter.

[0081] Fig.10 2 is a diagram for explaining an example of detecting the end point of etching of the first film 201 and the second film 202 according to the embodiment. Fig.10 , a line L1 schematically showing the time-dependent change of a signal (VI signal) periodically measured by the measuring unit 35b during the etching of the substrate W in the period T33, and a line L2 schematically showing the time-dependent change of a signal (VI signal) measured during the period T34 are shown. The lines L1 and L2 respectively show the change of the average value during the period T33 and the period T34, for example. Fig.10 , a line L3 indicating the time differential of line L1 and a line L4 indicating the time differential of line L2 are shown. Line L3 indicates the amount of change per unit time of line L1. Line L4 indicates the amount of change per unit time of line L2.

[0082] The detection unit 102b detects the end point of the etching of the first film 201 based on the change of the signal measured by the measurement unit 35b at the time of the period T33. For example, the detection unit 102b performs time differentiation on the signal shown by the line L1, obtains the amount of change per unit time shown by the line L3, and detects the end point of the etching of the first film 201 based on the time T41 when the amount of change becomes an extreme value. For example, the plasma processing device 1 detects the time when a predetermined margin time MT1 has passed from the time T41 as the end point of the etching of the first film 201. The margin time MT1 is the time from the time T41 when the etching of the first film 201 is considered to be completed. The margin time MT1 is determined, for example, by experiments or simulations.

[0083] In addition, the detection unit 102b detects the end point of the etching of the second film 202 based on the change of the signal measured by the measurement unit 35b at the time of the period T34. For example, the detection unit 102b performs time differentiation on the signal shown by the line L2, obtains the amount of change per unit time shown by the line L4, and detects the end point of the etching of the second film 202 based on the time T42 when the amount of change becomes an extreme value. For example, the plasma processing device 1 detects the time when a predetermined remaining time MT2 has passed from the time T42 as the end point of the etching of the second film 202. The remaining time MT2 is the time from the time T42 when the etching of the second film 202 is considered to be completed. The remaining time MT2 is determined, for example, by experiments or simulations.

[0084] In addition, the detection unit 102b may detect the time T41 and time T42 when the change amount reaches the extreme value as the end point of etching of the first film 201 and the second film 202. In addition, the detection unit 102b may detect the time when the change of the signal shown by the lines L1 and L2 is saturated as the end point of etching of the first film 201 and the second film 202.

[0085] Here, for example, when the etching end point is detected based on the moving average of the signal continuously measured by the VI probe as in the prior art, the signals in the periods T31 and T32 other than the period in which LF is supplied become noise, and the etching end point cannot be detected with high accuracy.

[0086] On the other hand, Figure 8 In the etching of the present embodiment shown, the period T33 contributes most to the etching and the selectivity of the first film 201, and the period T34 contributes most to the etching and the selectivity of the second film 202. Therefore, the detection unit 102b detects the end of etching based on a change in at least any one of the voltage, current, and phase difference between the voltage and current measured in the periods T33 and T34, and can detect the end of etching of the first film 201 and the second film 202 with high accuracy.

[0087] The plasma control unit 102a controls the plasma processing based on the detection result of the detection unit 102b. For example, when the detection unit 102b detects the end point of the first etching, the plasma control unit 102a performs control such that the period of etching the first film 201 in one cycle is shortened, deleted, or allocated to another period in one cycle. In addition, when the plasma control unit 102a detects the end point of etching the second film 202, the plasma control unit 102a performs control such that the period of etching the second film 202 in one cycle is shortened, deleted, or allocated to another period in one cycle.

[0088] Fig.11A and Fig. 11B This is a diagram schematically showing an example of changes in periodic electric power supplied from the power source 30 according to the embodiment.

[0089] Fig.11A The figure shows that when the end point of the first etching is detected, the period T33 of etching the first film 201 in one cycle is deleted. As a result, one cycle is shortened, and the second film 202 is etched in a shorter cycle, so the second film 202 is etched quickly.

[0090] Fig. 11B This shows that when the end point of the first etching is detected, the period T33 for etching the first film 201 in one cycle is allocated to the period T34. This increases the period T34 for etching the second film 202 in one cycle, so that the etching of the second film 202 proceeds rapidly.

[0091] When the first film 201 and the end point of etching of the first film 201 are detected by the detection portion 102 b , the plasma control portion 102 a ends the plasma etching.

[0092] In addition, in the above-mentioned embodiment, the case where the end point of the plasma processing is detected based on the signal input from the measuring parts 35a and 35b during the period T33 and T34 within one cycle in synchronization with the cycle of the electric power supplied from the power supply 30 to the plasma processing chamber 10 is described as an example. However, it is not limited to this. The detecting part 102b may also use a specific signal as a trigger, and detect the end point of the plasma processing based on the signal input from the measuring parts 35a and 35b at the time after a predetermined period has passed since the trigger.

[0093] Fig.12 An example of detecting the end point of etching according to an embodiment of the present invention is described below. Fig.121 shows the change of one cycle of the periodic electric power supplied to the plasma processing chamber 10. "HF" indicates the change of the electric power of the generated source RF signal. "LF" indicates the change of the electric power of the bias RF signal. Fig.12 In the embodiment, one cycle of the periodic electric power is divided into periods T51 to T55. HF is not supplied during period T51, and is high power during period T52. The power gradually decreases during periods T53 and T54, and the power during period T55 is the same as that during period T54. LF is not supplied during periods T51 to T53, and is medium power during period T54, and is high power during period T55. Different etching target films are etched during periods T54 and T55, respectively. For example, during period T54, the first film 201 of substrate W is etched. During period T55, the second film 202 of substrate W is etched. Fig.12 1 and 2 schematically show the change of the signal (VI signal) measured by the measuring units 35a and 35b during the period T51 to T55. VI (HF) schematically shows the change of the signal measured by the measuring unit 35a provided in the conductive part 33a where the source RF signal flows. VI (LF) schematically shows the change of the signal measured by the measuring unit 35b provided in the conductive part 33b where the bias RF signal flows. The signal VI (HF) changes greatly due to the supply of the source RF signal during the period T22. The change of the signal can be used as a trigger to detect the end point of the plasma treatment based on the signal input from the measuring units 35a and 35b at a time after a predetermined period has passed since the trigger. For example, at a time T57 after a predetermined time T56 from the time when the signal measured by the measuring unit 35a rises by a predetermined amplitude or more, the end point of the etching of the first film 201 is detected based on the signal input from the measuring unit 35b. In addition, when a predetermined time T58 has passed from time T56, the end point of etching of the second film 202 is detected based on the signal input from the measuring unit 35b. Time T57 is the time elapsed from time T56, which is considered to be the period T54. Time T58 is the time elapsed from time T56, which is considered to be the period T55. Time T57 and time T58 are determined, for example, by experiments or simulations.

[0094] Alternatively, the detection unit 102b may sample the values ​​of the signals input from the measurement units 35a and 35b in one cycle, and detect the end point of the plasma processing based on changes in the sampled values ​​in one cycle.

[0095] Fig.13 An example of detecting the end point of etching according to an embodiment of the present invention is described below. Fig.131 schematically shows the change of the signal (VI signal) measured by the measuring parts 35a and 35b within one cycle of the periodic electric power supplied to the plasma processing chamber 10. VI (HF) schematically shows the change of the signal measured by the measuring part 35a provided in the conductive part 33a where the source RF signal flows. VI (LF) schematically shows the change of the signal measured by the measuring part 35b provided in the conductive part 33b where the bias RF signal flows. Fig.13 In the embodiment, one cycle of the periodic electric power is divided into periods T61 to T65. For example, in period T64, the first film 201 of the substrate W is etched. In period T65, the second film 202 of the substrate W is etched. For example, when the etching of the first film 201 of the substrate W is completed, Fig.13 As shown, VI(LF) changes during period T64.

[0096] The detection unit 102b samples the values ​​of the signals input from the measuring units 35a and 35b in one cycle, and detects the end point of the plasma treatment based on the changes in the sampled values ​​in one cycle. For example, the detection unit 102b samples the values ​​of the signals input from the measuring units 35a and 35b in one cycle, and obtains the frequency of occurrence of the values ​​during one cycle based on the sampled data. Fig.13 The frequency of occurrence of the values ​​of VI(HF) and VI(LF) in one cycle is shown in . The detection unit 102b obtains the group with high frequency of occurrence and obtains the representative value for each group. The representative value may be, for example, the average value or the median value of the group. Fig.13 , the representative values ​​of the groups with high occurrence frequencies of VI(HF) and VI(LF) are represented as L0, L1, L2, ... The detection unit 102b detects the end point of the plasma treatment according to the change of the representative value for each group. For example, the detection unit 102b detects the end point of the etching of the first film 201 according to the change from the representative value L1 of VI(LF) to L1'.

[0097] Next, a description will be given of a processing flow of an endpoint detection method performed by the plasma processing apparatus 1 according to the embodiment. Fig.14 1 is a diagram for explaining an example of a processing sequence of an endpoint detection method according to an embodiment. The plasma processing apparatus 1 places a substrate W having a first etching target film and a second etching target film formed thereon on a substrate support portion 11. For example, the plasma processing apparatus 1 places a substrate W having a first etching target film and a second etching target film formed thereon. Figure 6 The substrate W of the first film 201 and the second film 202 shown is placed on the substrate support portion 11 . Fig.14 The processing of the endpoint detection method shown is performed while etching is in progress.

[0098] The plasma control unit 102a starts etching (S10). For example, the plasma control unit 102a controls the exhaust system 40 to exhaust the plasma processing chamber 10 to a specified vacuum level. The plasma control unit 102a controls the gas supply unit 20 to introduce a processing gas for etching from the gas supply unit 20 into the plasma processing space 10s. The plasma control unit 102a controls the power supply 30 to supply electric power from the power supply 30 to the plasma processing chamber 10 to plasma-form the processing gas, and starts etching, wherein the electric power is a periodic electric power that changes the electric power level in each period within one cycle. For example, the plasma control unit 102a controls the power supply 30 to supply electric power from the power supply 30 to the plasma processing chamber 10 to plasma-form the processing gas. Figure 7 The periodic electrical power shown.

[0099] The detection unit 102b detects the end point of the plasma processing based on the change of at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b at a time synchronized with the period of the periodic electric power supplied from the power supply 30 to the plasma processing chamber 10 (S11). For example, the detection unit 102b detects the end point of the etching of the first film 201 based on the change of the signal measured by the measuring unit 35b at the time of the period T33. In addition, the detection unit 102b detects the end point of the etching of the second film 202 based on the change of the signal measured by the measuring unit 35b at the time of the period T34.

[0100] The plasma control unit 102a determines whether the etching end point is detected by the detection unit 102b (S12). If the etching end point is not detected (S12: No), the process proceeds to S11.

[0101] On the other hand, if the etching endpoint is detected (S12: Yes), the plasma control unit 102a determines whether the etching endpoints of the first film 201 and the second film 202 are detected (S13). If the etching endpoints of the first film 201 and the second film 202 are not detected (S13: No), the process proceeds to S14.

[0102] The plasma control unit 102a controls the plasma processing based on the detection result of the detection unit 102b (S14), and transfers to S11. For example, when the end point of the etching of the first film 201 is detected by the detection unit 102b, the plasma control unit 102a controls to shorten, delete, or allocate the period of etching the first film 201 in one cycle to the period of etching the second film 202. In addition, when the end point of the etching of the second film 202 is detected, the plasma control unit 102a controls to shorten, delete, or allocate the period of etching the second film 202 in one cycle to the period of etching the first film 201.

[0103] On the other hand, when the etching endpoints of the first film 201 and the second film 202 are detected (S13: Yes), the plasma control unit 102a ends the etching (S15) and ends the process. For example, when the etching endpoints of the first film 201 and the second film 202 are detected, the plasma control unit 102a ends the etching.

[0104] In addition, in the above-mentioned embodiment, the case where the end point of etching is detected based on the change of at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring units 35a and 35b is described as an example. However, it is not limited to this. Regarding the voltage and current measured by the measuring units 35a and 35b, the maximum value, cycle (frequency), average value, and effective value of the waveform all change before and after the moment of just etching (Just etch). Therefore, the detection unit 102b can also detect the end point of etching based on the change of the maximum value, cycle (frequency), average value, and effective value of any one of the voltage and current, and the change of the phase difference between the voltage and the current. In addition, the detection unit 102b can also detect the end point of etching based on the change of the impedance value, reactance value, electric power value, and power factor calculated from the voltage, current, and phase difference between the voltage and the current. In this case, the detection unit 102b can also detect the end point of etching with high precision.

[0105] In addition, in the above-mentioned embodiment, the case where the measuring units 35a and 35b are provided as the measuring unit 35 is described as an example. However, it is not limited to this. In order to measure the state of plasma in the plasma processing chamber 10, the measuring unit 35 can be provided on an electrode disposed in the plasma processing chamber 10 or a wiring connected to the electrode. For example, an electrode for measurement may be disposed in the plasma processing chamber 10, and the measuring unit 35 may be provided on the electrode or the wiring connected to the electrode. In addition, in the present embodiment, the measuring units 35a and 35b are provided at a position closer to the plasma processing chamber 10 than the impedance matching circuits 34a and 34b. Thus, the measuring unit 35 can measure the state of plasma in the plasma processing chamber 10.

[0106] In addition, in the above-mentioned embodiment, the case where the measuring units 35a and 35b are provided as the measuring unit 35 to detect the end point of etching is described as an example. However, it is not limited to this. The end point of etching may be detected by only one of the measuring units 35a and 35b. For example, the end point of etching may be detected by only the measuring unit 35b provided in the conductive part 33b where the bias RF signal contributing to etching flows.

[0107] As described above, the plasma processing apparatus 1 of the embodiment includes a plasma processing chamber 10, electrodes (conductive components of the substrate support 11, conductive components of the shower head 13), measuring units 35a, 35b, a gas supply unit 20, a power supply 30, and a detection unit 102b. The plasma processing chamber 10 is provided with a substrate support 11 (a mounting table) capable of mounting a substrate W therein. The electrode is arranged in the plasma processing chamber 10. The measuring units 35a, 35b are provided on the electrode or the conductive units 33a, 33b (wiring) connected to the electrode, and measure at least one of the voltage and the current. The gas supply unit 20 supplies gas for plasma formation into the plasma processing chamber 10. The power supply 30 supplies electric power for plasma formation of the gas supplied into the plasma processing chamber 10, which is a periodic electric power that changes the electric power level in each period within one cycle. The detection unit 102b detects the end point of the first etching based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b at a first moment in one cycle of the periodic electric power. The detection unit 102b detects the end point of the second etching based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b at a second moment different from the first moment in one cycle. Thus, the plasma processing apparatus 1 can detect the end point of etching with high accuracy.

[0108] In addition, the substrate W has a first film 201 (a first etching target film) and a second film 202 (a second etching target film). The detection unit 102b detects the end point of the first etching, which is the end point of etching the first film 201, based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b at the first moment. The detection unit 102b detects the end point of the second etching, which is the end point of etching the second film 202, based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b at the second moment. Thus, the plasma processing apparatus 1 can detect the end point of etching the first film 201 and the end point of etching the second film 202 with high accuracy.

[0109] In addition, the substrate W has a first film 201 (a first etching target film) and a second film 202 (a second etching target film). The power supply 30 periodically supplies at least one of a first electric power (a generation source RF signal) of a first frequency and a second electric power (a bias RF signal) of a second frequency in a manner that changes the electric power level in each period within one cycle, wherein the first electric power is used to generate plasma, the second electric power is used to attract ion components in the plasma to the substrate W, and the second frequency is lower than the first frequency. The detection unit 102b detects the end point of the first etching, which is the end point of the etching of the first film 201, based on the change in at least one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b at the first moment (period T33) when the combination of the supplied first electric power and the second electric power contributes most to the etching of the first film 201 and the selectivity. The detection unit 102b detects the end point of the second etching, which is the end point of the etching of the second film 202, based on the change in at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b at the second time (period T34) when the combination of the supplied first electric power and the second electric power contributes most to the etching of the second film 202 and the selectivity. Thus, the plasma processing apparatus 1 can detect the end point of the etching of the first film 201 and the end point of the etching of the second film 202 with high accuracy.

[0110] In addition, the detection unit 102b detects the end point of the first etching and the end point of the second etching based on the change of at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring units 35a and 35b during the supply of the second electric power. Thus, the plasma processing apparatus 1 can detect the end point of the etching of the first film 201 and the end point of the etching of the second film 202 with high accuracy.

[0111] In addition, the plasma processing device 1 further includes a plasma control unit 102a. The plasma control unit 102a performs the following control: when the end point of the first etching is detected by the detection unit 102b, the period of performing the first etching in one cycle is shortened, deleted, or allocated to another period in one cycle; when the end point of the second etching is detected, the period of performing the second etching in one cycle is shortened, deleted, or allocated to another period in one cycle. Thus, the plasma processing device 1 can accelerate the etching of the first film 201 and the second film 202.

[0112] In addition, the first time and the second time are synchronized with the cycle of the electric power. Thus, the plasma processing apparatus 1 can detect the end point of etching the first film 201 and the end point of etching the second film 202 with high accuracy.

[0113] The first and second times are times after a predetermined period of time has passed since the specific signal from the measuring units 35a and 35b was used as a trigger. Thus, the plasma processing apparatus 1 can detect the etching endpoint with high accuracy by detecting the specific signal without detecting the cycle of the electric power.

[0114] In addition, the electrode is provided on the substrate support portion 11. An impedance matching circuit 34b (matching circuit) is provided on the conductive portion 33b (wiring) connected to the electrode, and electric power is supplied to the conductive portion 33b from the power supply 30. The measuring portion 35b is provided at a position closer to the electrode side than the impedance matching circuit 34b of the conductive portion 33b. Thus, the measuring portion 35b can detect the change of voltage and current caused by the change of the plasma state in the plasma processing chamber 10 with high accuracy. Thus, the plasma processing apparatus 1 can detect the end point of etching with high accuracy.

[0115] The above embodiments are described, but it should be considered that the embodiments of this specification are illustrative and non-restrictive in all aspects. In fact, the above embodiments can be implemented in many ways. In addition, the above embodiments can also be omitted, replaced, and changed in various ways without departing from the claims and their main purpose.

[0116] For example, in the above-mentioned embodiment, the case where the plasma treatment is performed on a semiconductor wafer as the substrate W is described as an example, but the present invention is not limited to this. The substrate W may be any substrate.

[0117] In addition, in the above-mentioned embodiment, the plasma processing apparatus 1 adopts a structure in which the power supply 30 includes a first RF generating unit 31a and a second RF generating unit 31b for generating plasma, and uses high frequency (RF) to generate plasma. However, it is not limited to this. The plasma processing apparatus 1 may also adopt a structure in which plasma is generated by microwaves, and ion components in the plasma are introduced into the substrate W by applying a rectangular DC voltage to the conductive member of the substrate support part 11. For example, the plasma processing apparatus 1 may also be configured such that the first RF generating unit 31a is replaced by a microwave power supply, and the second RF generating unit 31b is replaced by a DC power supply that applies a rectangular DC voltage.

[0118] In addition, in the above-mentioned embodiment, the case where the first film 201 and the second film 202 formed on the substrate W are etched as the first etching target film and the second etching target film is described as an example. However, it is not limited to this. It is also possible that one or more etching target films are formed on the substrate W, and the one or more etching target films are etched using periodic electric power that changes the electric power level in each period within one cycle. For example, the substrate W may also be formed with a third etching target film. The detection unit 102b may also detect the end point of the third etching as the end point of the etching of the third etching target film based on the change of at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring units 35a and 35b at a third moment in one cycle different from the first moment and the second moment. For example, the detection unit 102b may detect the end point of the third etching based on the change of at least any one of the voltage, current, and phase difference between the voltage and the current measured by the measuring units 35a and 35b during the supply of the second electric power (bias RF signal). Thus, the plasma processing apparatus 1 can detect the end point of etching of the third etching target film with high accuracy.

[0119] In addition, it should be considered that the embodiments of this specification are illustrative and non-restrictive in all aspects. In fact, the above-mentioned embodiments can be implemented in many ways. In addition, the above-mentioned embodiments can also be omitted, replaced, and changed in various ways without departing from the claims and their subject matter.

[0120] In addition, regarding the above-mentioned embodiment, the following supplementary notes are further described.

[0121] (Note 1)

[0122] A plasma processing device, comprising:

[0123] A chamber having a mounting table capable of mounting a substrate disposed therein;

[0124] an electrode disposed in the chamber;

[0125] a measuring unit provided on the electrode or a wiring connected to the electrode and capable of measuring either voltage or current;

[0126] a gas supply unit capable of supplying a gas for plasma formation into the chamber;

[0127] a power supply capable of supplying electric power for plasma-forming the gas supplied into the chamber to the chamber, wherein the electric power is periodic electric power having a power level changed in each period within one cycle; and

[0128] A detection unit detects an end point of a first etching based on at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit at a first moment in the one cycle of the periodic electric power, and detects an end point of a second etching based on at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit at a second moment different from the first moment in the one cycle.

[0129] (Note 2)

[0130] The plasma processing apparatus according to Supplement 1, wherein:

[0131] The substrate has a first etching target film and a second etching target film.

[0132] The detection unit detects the end point of the first etching, which is the end point of etching of the first etching object film, based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the first moment, and detects the end point of the second etching, which is the end point of etching of the second etching object film, based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the second moment.

[0133] (Note 3)

[0134] The plasma processing apparatus according to Supplement 1, wherein:

[0135] The substrate has a first etching target film and a second etching target film.

[0136] The power supply periodically supplies at least one of a first electric power of a first frequency and a second electric power of a second frequency in a manner of changing the electric power level in each period within one cycle, wherein the first electric power is used to generate plasma, the second electric power is used to attract ion components in the plasma to the substrate, and the second frequency is lower than the first frequency.

[0137] The detection unit detects the end point of the first etching, which is the end point of etching of the first etching object film, based on a change in at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the first moment when the combination of the first electric power and the second electric power supplied contributes the most to the etching of the first etching object film and the selectivity, and detects the end point of the second etching, which is the end point of etching of the second etching object film, based on a change in at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the second moment when the combination of the first electric power and the second electric power supplied contributes the most to the etching of the second etching object film and the selectivity.

[0138] (Note 4)

[0139] The plasma processing apparatus according to Supplement 3, wherein:

[0140] The detection unit detects the end points of the first etching and the second etching based on a change in at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit while the second electric power is supplied.

[0141] (Note 5)

[0142] The plasma processing apparatus according to Supplement 3 or 4, wherein:

[0143] The power source includes a first power source for supplying the first electric power and a second power source for supplying the second electric power,

[0144] The first power source is a microwave power source or a high frequency (RF) power source,

[0145] The second power source is a high frequency (RF) power source or a power source capable of applying a DC voltage in a rectangular shape.

[0146] (Note 6)

[0147] The plasma processing apparatus according to any one of Supplementary Notes 1 to 5, wherein:

[0148] The device also includes a plasma control unit, which performs the following control:

[0149] When the end point of the first etching is detected by the detection unit, the period for performing the first etching in the one cycle is shortened, deleted, or allocated to another period in the one cycle,

[0150] When the end point of the second etching is detected by the detection unit, the period for performing the second etching in the one cycle is shortened, deleted, or allocated to another period in the one cycle.

[0151] (Note 7)

[0152] The plasma processing apparatus according to any one of Supplementary Notes 1 to 6, wherein:

[0153] The first time and the second time are synchronized with a cycle of the electric power.

[0154] (Note 8)

[0155] The plasma processing apparatus as described in any one of Supplementary Notes 1 to 6, wherein:

[0156] The first time and the second time are times after a predetermined period of time has elapsed since a specific signal from the measuring unit is used as a trigger.

[0157] (Note 9)

[0158] The plasma processing apparatus according to any one of Supplementary Notes 1 to 8, wherein:

[0159] The electrode is arranged on the mounting table,

[0160] A matching circuit is provided on the wiring connected to the electrode so that the electric power can be supplied from the power supply to the wiring.

[0161] The measuring unit is provided at a position of the wiring closer to the electrode than the matching circuit.

[0162] (Note 10)

[0163] The plasma processing apparatus according to any one of Supplementary Notes 1 to 9, wherein:

[0164] The substrate further has a third etching target film,

[0165] The detection unit detects the endpoint of the third etching, which is the endpoint of etching of the third etching object film, based on a change in at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at a third moment within the one cycle different from the first moment and the second moment.

[0166] (Note 11)

[0167] The plasma processing apparatus according to Supplementary Note 10, wherein:

[0168] The detection unit detects an end point of the third etching based on a change in at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit while the second electric power is supplied.

[0169] (Note 12)

[0170] An endpoint detection method comprising:

[0171] A step of supplying a gas for plasma formation into a chamber, wherein the chamber has a mounting table capable of mounting a substrate therein;

[0172] A step of supplying electric power for plasma-forming the gas supplied into the chamber to the chamber, wherein the electric power is a periodic electric power having a power level changed in each period within one cycle (i.e., one period); and

[0173] A step of detecting an end point of a first etching based on at least any one of a voltage, a current, or a phase difference between the voltage and the current measured by a measuring unit at a first moment in said one cycle of the periodic electric power, and detecting an end point of a second etching based on at least any one of a voltage, a current, or a phase difference between the voltage and the current measured by the measuring unit at a second moment different from the first moment in said one cycle, wherein the measuring unit is provided on an electrode arranged in the chamber or on a wiring connected to the electrode, and is used to measure at least any one of the voltage and the current.

[0174] Description of Reference Numerals

[0175] 1 Plasma treatment device

[0176] 10 Plasma Processing Chamber

[0177] 11. Substrate support portion

[0178] 13 Sprinkler

[0179] 20 Gas supply unit

[0180] 30 Power Supply

[0181] 31 RF Power Supply

[0182] 31a First RF generating unit

[0183] 31b Second RF generation unit

[0184] 32DC power supply

[0185] 32a First DC generating unit

[0186] 32b Second DC generating unit

[0187] 33a, 33b conductive parts

[0188] 34a, 34b impedance matching circuit

[0189] 35, 35a, 35b measuring part

[0190] 40 Exhaust System

[0191] 100 Control Department

[0192] 101 External Interface

[0193] 102 Process Controller

[0194] 102a Plasma control unit

[0195] 102b Detection Department

[0196] 103 User Interface

[0197] 104 Storage

[0198] 200 Basement membrane

[0199] 201 First Film

[0200] 202 Second Film

[0201] 203 The Third Membrane

[0202] 205 Structure

[0203] 1110 Base

[0204] W substrate.

Claims

1. A plasma processing device, characterized in that: include: A chamber having a mounting table capable of mounting a substrate disposed therein; an electrode disposed in the chamber; a measuring unit provided on the electrode or a wiring connected to the electrode and capable of measuring either voltage or current; a gas supply unit capable of supplying a gas for plasma formation into the chamber; a power supply capable of supplying electric power for plasma-forming the gas supplied into the chamber to the chamber, wherein the electric power is periodic electric power having a power level changed in each period within one cycle; and A detection unit detects an end point of a first etching based on at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit at a first moment in the one cycle of the periodic electric power, and detects an end point of a second etching based on at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit at a second moment different from the first moment in the one cycle.

2. The plasma processing device according to claim 1, wherein: The substrate has a first etching target film and a second etching target film. The detection unit detects the end point of the first etching, which is the end point of etching of the first etching object film, based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the first moment, and detects the end point of the second etching, which is the end point of etching of the second etching object film, based on at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the second moment.

3. The plasma processing apparatus according to claim 1, wherein: The substrate has a first etching target film and a second etching target film. The power supply periodically supplies at least one of a first electric power of a first frequency and a second electric power of a second frequency in a manner that changes the electric power level in each period within one cycle, wherein the first electric power is used to generate plasma, the second electric power is used to attract ion components in the plasma to the substrate, and the second frequency is lower than the first frequency. The detection unit detects the end point of the first etching, which is the end point of etching of the first etching object film, based on a change in at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the first moment when the combination of the first electric power and the second electric power supplied contributes the most to the etching of the first etching object film and the selectivity, and detects the end point of the second etching, which is the end point of etching of the second etching object film, based on a change in at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at the second moment when the combination of the first electric power and the second electric power supplied contributes the most to the etching of the second etching object film and the selectivity.

4. The plasma processing device according to claim 3, wherein: The detection unit detects the end points of the first etching and the second etching based on a change in at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit while the second electric power is supplied.

5. The plasma processing apparatus according to claim 3, wherein: The power supply includes: a first power supply that supplies the first electric power; and a second power supply that supplies the second electric power, The first power source is a microwave power source or a high frequency (RF) power source, The second power source is a high frequency (RF) power source or a power source capable of applying a DC voltage in a rectangular shape.

6. The plasma processing apparatus according to claim 1, wherein: The device also includes a plasma control unit, which performs the following control: When the end point of the first etching is detected by the detection unit, the period for performing the first etching in the one cycle is shortened, deleted, or allocated to another period in the one cycle, When the end point of the second etching is detected by the detection unit, the period for performing the second etching in the one cycle is shortened, deleted, or allocated to another period in the one cycle.

7. The plasma processing apparatus according to claim 1, wherein: The first time and the second time are synchronized with a cycle of the electric power.

8. The plasma processing apparatus according to claim 1, wherein: The first time and the second time are times after a predetermined period of time has elapsed since a specific signal from the measuring unit is used as a trigger.

9. The plasma processing apparatus according to claim 1, wherein: The electrode is arranged on the mounting table, A matching circuit is provided on the wiring connected to the electrode so that the electric power can be supplied from the power supply to the wiring. The measuring unit is provided at a position of the wiring closer to the electrode than the matching circuit.

10. The plasma processing apparatus according to claim 3, wherein: The substrate further has a third etching target film, The detection unit detects the endpoint of the third etching, which is the endpoint of etching of the third etching object film, based on a change in at least any one of the voltage, current, and phase difference between the voltage and current measured by the measuring unit at a third moment within the one cycle different from the first moment and the second moment.

11. The plasma processing apparatus according to claim 10, wherein: The detection unit detects an end point of the third etching based on a change in at least any one of a voltage, a current, and a phase difference between the voltage and the current measured by the measurement unit while the second electric power is supplied.

12. An endpoint detection method, characterized in that: include: A step of supplying a gas for plasma formation into a chamber, wherein the chamber has a mounting table capable of mounting a substrate therein; supplying electric power for converting the gas supplied into plasma to the chamber, wherein the electric power is periodic electric power having a power level changed in each period within one cycle; and A step of detecting an end point of a first etching based on at least any one of a voltage, a current, or a phase difference between the voltage and the current measured by a measuring unit at a first moment in said one cycle of the periodic electric power, and detecting an end point of a second etching based on at least any one of a voltage, a current, or a phase difference between the voltage and the current measured by the measuring unit at a second moment different from the first moment in said one cycle, wherein the measuring unit is provided on an electrode arranged in the chamber or on a wiring connected to the electrode, and is used to measure at least any one of the voltage and the current.

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