Measuring device and method for determining the thickness of a sheath

Abstract

The present invention provides a measuring device and a method for measuring the thickness of a sheath layer, which can measure the thickness of a sheath layer without installing a dedicated measuring device in a plasma processing apparatus. A disclosed measuring device includes a substrate and a transmission circuit, a transmission antenna, a reception antenna, a reception demodulation circuit, and an arithmetic device provided in or on the substrate. The transmission circuit generates microwaves. The transmission antenna transmits the microwaves generated by the transmission circuit as transmission waves. The reception antenna receives at least a reflection wave of the transmission wave reflected by the plasma above a substrate support as a reception wave. The reception demodulation circuit generates a signal reflecting the thickness of the sheath layer between the substrate and the plasma from the reception wave. The arithmetic device measures the thickness of the sheath layer from the signal generated by the reception demodulation circuit.

Description

TECHNICAL FIELD

[0001] An example embodiment of the present application relates to a measurer and a method of obtaining a thickness of a sheath. BACKGROUND

[0002] A plasma processing apparatus is used in the manufacture of electronic devices. The plasma processing apparatus has a chamber and a substrate support. The substrate support supports a substrate within the chamber. When a plasma is generated within the chamber, a sheath (plasma sheath) is formed between the substrate on the substrate support and the plasma. The thickness of the sheath affects the plasma processing of the substrate.

[0003] Patent Document 1 described below describes a plasma processing apparatus capable of obtaining a thickness of a sheath. The plasma processing apparatus has a laser length measuring unit for measuring the thickness of the sheath.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-353199 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The present application provides a technique of obtaining a thickness of a sheath without installing a dedicated measuring device in a plasma processing apparatus.

[0009] TECHNICAL SOLUTION TO SOLVE THE PROBLEMS

[0010] In one example embodiment, a measurer is provided. The measurer includes a substrate, a transmission circuit, a transmission antenna, at least one reception antenna, a reception demodulation circuit, and an arithmetic unit. The substrate is capable of being placed on a substrate support of a plasma processing apparatus. The transmission circuit, the transmission antenna, the at least one reception antenna, the reception demodulation circuit, and the arithmetic unit are provided in or on the substrate. The transmission circuit is capable of generating microwaves. The transmission antenna is capable of transmitting the microwaves generated by the transmission circuit as a transmission wave. The at least one reception antenna is capable of receiving a reflection wave of the transmission wave reflected by a plasma above the substrate support as at least one reception wave. The reception demodulation circuit is capable of generating at least one signal reflecting a thickness of a sheath between the substrate and the plasma from the at least one reception wave. The arithmetic unit is capable of obtaining the thickness of the sheath from the at least one signal.

[0011] EFFECTS OF THE INVENTION

[0012] According to one example embodiment, it is possible to obtain a thickness of a sheath without installing a dedicated measuring device in a plasma processing apparatus. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Fig. 1 is a plan view of a measurement device of an example embodiment.

[0014] Figure 2 Fig. 2 is a diagram schematically showing a plasma processing apparatus.

[0015] Figure 3 Fig. 3 is a plan view of a measurement unit of a measurement device of an example embodiment.

[0016] Figure 4 Fig. 4 is a diagram showing the structure of a measurement unit of a measurement device of an example embodiment.

[0017] Figure 5 Fig. 5 is a diagram showing the transmission of microwaves between a transmission antenna and a reception antenna in a measurement device of an example embodiment.

[0018] Figure 6 Fig. 6 is a diagram showing the transmission direction of a transmission wave in a measurement device of an example embodiment. Figure 6

[0019] Figure 7 Fig. 7 is a plan view of an example of a transmission antenna that can be employed in a measurement device of an example embodiment.

[0020] Figure 8 Fig. 8 is a plan view of another example of a transmission antenna that can be employed in a measurement device of an example embodiment.

[0021] Figure 9 Fig. 9 is a diagram showing a measurement unit of an example embodiment.

[0022] Figure 10 Fig. 10 is a diagram showing a measurement unit of another example embodiment.

[0023] Figure 11 Fig. 11 is a diagram showing a measurement unit of yet another example embodiment.

[0024] Figure 12 Fig. 12 is a diagram showing a measurement unit of yet another example embodiment.

[0025] Figure 13 Fig. 13 is a diagram showing a measurement unit of yet another example embodiment.

[0026] BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 1 Measurement device

[0028] 2 Substrate

[0029] 3 Measurement unit

[0030] ​4 … transmission circuit

[0031] 5 … transmission antenna

[0032] 6 … reception antenna

[0033] 7 … reception demodulation circuit

[0034] 8 … arithmetic unit DETAILED DESCRIPTION

[0035] Hereinafter, various exemplary embodiments will be described.

[0036] In one exemplary embodiment, a measurer is provided. The measurer includes a substrate, a transmission circuit, a transmission antenna, at least one reception antenna, a reception demodulation circuit, and an arithmetic unit. The substrate is capable of being placed on a substrate support of a plasma processing apparatus. The transmission circuit, the transmission antenna, the at least one reception antenna, the reception demodulation circuit, and the arithmetic unit are provided in or on the substrate. The transmission circuit is capable of generating microwaves. The transmission antenna is capable of transmitting the microwaves generated by the transmission circuit as a transmission wave. The at least one reception antenna is capable of receiving a reflection wave of the transmission wave reflected by a plasma above the substrate support as at least one reception wave. The reception demodulation circuit is capable of generating at least one signal reflecting a thickness of a sheath layer between the substrate and the plasma from the at least one reception wave. The arithmetic unit is capable of calculating the thickness of the sheath layer from the at least one signal.

[0037] In the measurer of the above-described embodiment, the elements for calculating the thickness of the sheath layer, i.e., the transmission circuit, the transmission antenna, the at least one reception antenna, the reception demodulation circuit, and the arithmetic unit are provided in or on the substrate capable of being placed on the substrate support of the plasma processing apparatus. Therefore, by generating the plasma in a state where the measurer is placed on the substrate support, the thickness of the sheath layer can be calculated without installing a dedicated measuring apparatus in the plasma processing apparatus.

[0038] In one exemplary embodiment, it is also possible that the transmission direction of the transmission wave from the transmission antenna on the substrate support is an oblique upward direction. It is also possible that the measurer has a plurality of reception antennas as the at least one reception antenna. It is also possible that the plurality of reception antennas are arranged in a direction parallel to the substrate with respect to a component of the transmission direction of the transmission wave. It is also possible that the reception demodulation circuit is capable of generating a plurality of signals indicating intensities of a plurality of reception waves respectively received by the plurality of reception antennas. It is also possible that the arithmetic unit is capable of calculating the thickness of the sheath layer from the plurality of signals.

[0039] In one illustrative embodiment, the transmission antenna can transmit a pulse of microwaves output from the transmission circuit as the transmission wave. The reception demodulation circuit can generate at least one signal indicative of the intensity of at least one reception wave. The operation device can calculate the delay time of at least one reception wave with respect to the transmission wave from the at least one signal, and calculate the thickness of the sheath layer from the delay time.

[0040] In one illustrative embodiment, the measurement device can have a plurality of reception antennas as the at least one reception antenna. The plurality of reception antennas can be arranged in a direction parallel to the substrate in the transmission direction of the transmission wave. The reception demodulation circuit can generate a plurality of signals indicative of the intensity of a plurality of reception waves respectively received by the plurality of reception antennas. The operation device can calculate a plurality of delay times of the plurality of reception waves respectively with respect to the transmission wave from the plurality of signals, and calculate the thickness of the sheath layer from the plurality of delay times.

[0041] In one illustrative embodiment, the reception demodulation circuit can generate at least one signal indicative of the phase difference between the transmission wave and at least one reception wave.

[0042] In one illustrative embodiment, the transmission circuit can alternately increase and decrease the frequency of the transmission wave monotonically. The reception demodulation circuit can mix the transmission wave and at least one reception wave to generate an intermediate frequency signal having a beat frequency reflecting the thickness of the sheath layer as the at least one signal.

[0043] In one illustrative embodiment, the transmission circuit can scan the transmission direction of the transmission wave in a manner in which the angle formed by the transmission direction of the transmission wave and the substrate is increased and decreased in synchronization with a reference signal having a prescribed frequency lower than the frequency of the transmission wave. The reception demodulation circuit can generate a signal indicative of the component of the prescribed frequency included in at least one reception wave as the at least one signal. The operation device can calculate the thickness of the sheath layer from the phase difference between the reference signal and the at least one signal.

[0044] In one illustrative embodiment, the transmission wave can be a millimeter wave.

[0045] In another exemplary embodiment, a method for determining the thickness of a sheath is provided. The method includes a) the step of mounting a measuring device on a substrate support within a cavity of a plasma processing apparatus. The measuring device includes a substrate, a transmitting circuit, a transmitting antenna, at least one receiving antenna, a receiving demodulation circuit, and a computational unit. The substrate can be mounted on the substrate support of the plasma processing apparatus. The transmitting circuit, the transmitting antenna, at least one receiving antenna, the receiving demodulation circuit, and the computational unit are disposed within or on the substrate. The transmitting circuit is capable of generating microwaves. The transmitting antenna is capable of transmitting the microwaves generated by the transmitting circuit as a transmitted wave. The at least one receiving antenna is capable of receiving a reflected wave of the transmitted wave reflected by plasma above the substrate support as at least one received wave. The receiving demodulation circuit is capable of generating at least one signal reflecting the thickness of the sheath between the substrate and the plasma based on the at least one received wave. The computational unit is capable of determining the thickness of the sheath based on the at least one signal. The method further includes b) the step of generating plasma within a cavity of the plasma processing apparatus. The method further includes c) the step of determining the thickness of the sheath based on the at least one signal in the computational unit of the measuring device mounted on the substrate support while plasma is generated within the cavity.

[0046] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the same or corresponding parts will be labeled with the same reference numerals in each drawing.

[0047] Figure 1 This is a plan view of a measuring device according to an exemplary implementation. Figure 1 The measuring device 1 shown is configured to measure the thickness of the sheath between the plasma and the measuring device 1, mounted on a substrate support disposed within the cavity of a plasma processing apparatus. The measuring device 1 includes a substrate 2. The substrate 2 can be mounted on the substrate support of the plasma processing apparatus. The substrate 2 can have a disk shape, such as a wafer. The substrate 2 can be formed, for example, from silicon.

[0048] Figure 2 This is a schematic diagram illustrating an example of a plasma processing apparatus. Measuring device 1 is capable of... Figure 2 The thickness of the sheath layer is measured on the substrate support 104 of the plasma processing apparatus 100 shown. Furthermore, the measuring device 1 can also be used to measure the thickness of the sheath layer in other plasma processing apparatuses.

[0049] like Figure 2 As shown, the plasma processing apparatus 100 has a chamber 102. The chamber 102 has a passage 102p on its sidewall. The substrate W and the measuring instrument 1, which are processed in the plasma processing apparatus 100, pass through the passage 102p when transported between the inner and outer sides of the chamber 102. The passage 102p can be opened and closed by a gate valve 102v.

[0050] The plasma processing apparatus 100 also has a substrate support 104. The substrate support 104 is provided in the chamber 102. The substrate support 104 is configured to support a substrate W placed thereon. The substrate support 104 is also capable of supporting the measurer 1 placed thereon.

[0051] The substrate support 104 can include a lower electrode 106 and an electrostatic chuck 108. The lower electrode 106 is formed of a conductor such as aluminum, and has a substantially disc shape. The electrostatic chuck 108 is provided on the lower electrode 106. The electrostatic chuck 108 is configured to hold the substrate W or the measurer 1 placed thereon by electrostatic attraction.

[0052] The substrate support 104 can also support an edge ring ER mounted thereon. The edge ring ER has a ring shape. The edge ring ER is formed of, for example, a silicon-containing material. The substrate W or the measurer 1 is placed on the electrostatic chuck 108 in an area surrounded by the edge ring ER.

[0053] The plasma processing apparatus can also have an upper electrode 109. The upper electrode 109 is supported by a top portion 102c of the chamber 102. The upper electrode 109 can be grounded.

[0054] The plasma processing apparatus 100 can also have a gas supply portion 110 and an exhaust apparatus 112. The gas supply portion 110 is configured to supply a gas into the chamber 102. In Figure 2 The gas supply portion 110 supplies the gas into the chamber 102 from the upper electrode 109 via the top portion 102c of the chamber 102, but can supply the gas into the chamber 102 from other portions. The exhaust apparatus 112 includes a pressure controller such as an automatic pressure control valve and a pressure-reducing pump such as a turbo molecular pump, a dry pump. The exhaust apparatus 112 is configured to adjust the pressure of the gas in the chamber 102 to a specified pressure.

[0055] The plasma processing apparatus 100 can also include a high-frequency power source 114. The high-frequency power source 114 is connected to the lower electrode 106 via a matcher 116. The high-frequency power source 114 supplies a high-frequency electric power to the lower electrode 106 to generate a plasma from a gas in the chamber 102. The matcher 116 includes a matching circuit for matching the impedance of the load of the high-frequency power source 114 to the output impedance of the high-frequency power source 114.

[0056] When the plasma is generated in the plasma processing apparatus 100, the gas is supplied from the gas supply part 110 into the chamber 102. Further, the pressure of the gas in the chamber 102 is regulated by the exhaust apparatus 112. Further, the high-frequency electric power is supplied from the high-frequency power source 114 to the lower electrode 106. As a result, the plasma PL is generated in the chamber 102. The sheath S is formed between the plasma PL and the substrate W on the substrate holder 104 or the gauge 1.

[0057] The gauge 1 also has one or more gauging parts 3 to measure the thickness of the sheath S on the substrate holder 104. In Figure 1 , the gauge 1 has five gauging parts 3, but the number of gauging parts 3 in the gauge 1 can be one or more. Further, in Figure 1 , one of the gauging parts 3 is disposed at the center of the substrate 2, and the other gauging parts 3 are arranged at equal intervals on a circle around the center of the substrate 2. However, one or more gauging parts 3 can be arranged at any position on the substrate 2. Further, one or more gauging parts 3 can each be formed as a chip and mounted on the substrate 2. Alternatively, one or more gauging parts 3 can each be formed in or on the substrate 2.

[0058] Hereinafter, the Figure 1 and Figure 3 and Figure 4 are described with reference to the drawings. Figure 3 is a plan view showing one gauging part of the gauge of one example embodiment. Figure 4 is a view showing the structure of one gauging part of the gauge of one example embodiment. Hereinafter, one gauging part 3 is described. Further, in the case where the gauge 1 has a plurality of gauging parts 3, the plurality of gauging parts 3 can have the same structure.

[0059] The gauging part 3 has a transmission circuit 4, a transmission antenna 5, at least one reception antenna 6, a reception demodulation circuit 7, and a calculator 8. The number of reception antennas 6 in the gauging part 3 can be one or more. The gauging part 3 can also have a battery 9 and a memory 10. The battery 9 is, for example, a full solid battery. The battery 9 is a power source for operating each part of the gauging part 3 (for example, the calculator 8). The memory 10 is a storage part for programs and data, and is connected to the calculator 8. The elements of the gauging part 3, that is, the transmission circuit 4, the transmission antenna 5, at least one reception antenna 6, the reception demodulation circuit 7, the calculator 8, the battery 9, and the memory 10 are disposed in or on the substrate 2.

[0060] The transmission circuit 4 is configured to be capable of generating microwaves. The frequency of the microwaves generated in the transmission circuit 4 can be any frequency within the microwave band. The frequency of the microwaves generated in the transmission circuit 4 can be a frequency within the millimeter wave band. The millimeter wave band is a frequency band of 30 GHz or more and 300 GHz or less. Alternatively, the frequency of the microwaves generated in the transmission circuit 4 can be a frequency within the sub-millimeter wave band. The sub-millimeter wave band is a frequency band of 300 GHz or more.

[0061] The transmission antenna 5 is connected to the transmission circuit 4. The transmission antenna 5 is configured to be capable of transmitting the microwaves generated by the transmission circuit 4 as a transmission wave. Figure 5 is a diagram showing the transmission of microwaves between the transmission antenna and the reception antenna of the measurement device of one illustrated embodiment. As shown in Figure 5 the transmission wave transmitted from the transmission antenna 5 has a directivity capable of being reflected by the plasma PL at the interface between the plasma PL and the sheath S and being received by the at least one reception antenna 6 as a reception wave. The transmission direction of the transmission wave transmitted from the transmission antenna 5 is the main axis direction of the transmission wave.

[0062] Figure 6 (a) of FIG. 10 and Figure 6 (b) of FIG. 10 are diagrams showing the transmission direction of the transmission wave in the measurement device of one illustrated embodiment. In Figure 6 (a) of FIG. 10 and Figure 6 (b) of FIG. 10 show the main lobe and the side lobe of the transmission wave. In Figure 6 (a) of FIG. 10 and Figure 6 (b) of FIG. 10, the X direction is a direction parallel to the substrate 2. The transmission antenna 5 and the reception antenna 6 are arranged along the X direction. The Y direction is a direction parallel to the substrate 2 and perpendicular to the X direction. The Z direction is a direction orthogonal to the substrate 2, the X direction, and the Y direction, and is a vertical direction in a state where the measurement device 1 is loaded on the substrate support 104. As shown in Figure 6 (a) of FIG. 10 and Figure 6 (b) of FIG. 10, the transmission direction of the transmission wave is an obliquely upward direction on the substrate support 104. The component of the transmission direction of the transmission wave parallel to the substrate 2 is the X direction.

[0063] The transmission antenna 5 can include one or more antenna elements. The one or more antenna elements include a radiating conductor. Figure 7 is a plan view showing one example of a transmission antenna that can be employed in the measurement device of one illustrated embodiment. Figure 7 The transmission antenna 5 shown in FIG. 11 includes a plurality of antenna elements, i.e., antenna elements 5a to 5e. The antenna elements 5a to 5e each include a radiating conductor. The radiating conductor of each of the antenna elements 5a to 5e can have a rectangular planar shape. The antenna elements 5a to 5e are arranged along the Y direction. The antenna elements 5a to 5e are connected to the transmission circuit 4.Figure 7 In the example shown, the transmission circuit 4 includes a microwave oscillator 4g and an amplifier 4a. The oscillator 4g is connected to the antenna elements 5a to 5e via the amplifier 4a. The microwave oscillator 4g is configured to output a microwave to the amplifier 4a. The amplifier 4a is configured to amplify the microwave from the microwave oscillator 4g and output the amplified microwave to the antenna elements 5a to 5e. Figure 7 The transmission antenna 5 shown is capable of transmitting a transmission wave whose directional component in the direction parallel to the substrate 2 is in the X direction. Further, the number of the plurality of antenna elements arranged in the Y direction in the transmission antenna 5 can be any number.

[0064] Figure 8 is a plan view of a transmission antenna capable of being employed in a measurement device of another example of one illustrated embodiment. Figure 8 The transmission antenna 5 shown includes a plurality of antenna element groups 51 to 53. The number of the antenna element groups in the transmission antenna 5 can be any number of two or more. The plurality of antenna element groups 51 to 53 are arranged in the X direction.

[0065] The plurality of antenna element groups 51 to 53 each have a plurality of antenna elements. The antenna element group 51 has antenna elements 511 to 514. The antenna element group 52 has antenna elements 521 to 524. The antenna element group 53 has antenna elements 531 to 534. Further, the number of the antenna elements each of the plurality of antenna element groups 51 to 53 has can be any number of two or more. Each of the above-described antenna elements includes a radiating conductor. The radiating conductor can have a rectangular planar shape. In each of the plurality of antenna element groups 51 to 53, the plurality of antenna elements are arranged in the Y direction.

[0066] Figure 8 The plurality of antenna elements of the transmission antenna 5 shown are connected to the transmission circuit 4. The transmission circuit 4 includes a microwave oscillator 4g, an amplifier 4a, and a phase shifter group 4p. The oscillator 4g is connected to the transmission antenna 5 via the amplifier 4a and the phase shifter group 4p. The phase shifter group 4p includes a phase shifter 41p, a phase shifter 42p, and a phase shifter 43p. The phase shifter 41p is connected between the amplifier 4a and the antenna element group 51. The phase shifter 42p is connected between the amplifier 4a and the antenna element group 52. The phase shifter 43p is connected between the amplifier 4a and the antenna element group 53. The microwave output from the amplifier 4a is distributed as a plurality of microwaves to the phase shifter 41p, the phase shifter 42p, and the phase shifter 43p. The plurality of microwaves are respectively applied with individual phases by the phase shifter 41p, the phase shifter 42p, and the phase shifter 43p, and are respectively applied to the plurality of antenna element groups 51 to 53. The transmission wave from the transmission antenna 5 is a resultant wave of the microwaves emitted from the plurality of antenna element groups 51 to 53. The angle θ that the transmission direction of the transmission wave from the transmission antenna 5 makes with the substrate 2 is adjusted by the phases respectively set in the phase shifter 41p, the phase shifter 42p, and the phase shifter 43p in the plurality of microwaves.

[0067] Referring again to Figure 1 ,Figure 3 , and Figure 4 The at least one receiving antenna 6 is configured to receive a reflected wave of the transmitted wave reflected by the plasma PL as a received wave. As shown in Figure 3 The measurement unit 3 includes a plurality of receiving antennas 61 to 66 as the at least one receiving antenna 6. The plurality of receiving antennas 61 to 66 are arranged in the X direction. The number of the receiving antennas in the measurement unit 3 is one or more, and can be any number. The at least one receiving antenna 6 is connected to a receiving demodulation circuit 7.

[0068] The receiving demodulation circuit 7 receives the at least one received wave received by the at least one receiving antenna 6. The receiving demodulation circuit 7 is configured to generate at least one signal from the at least one received wave. The at least one signal generated by the receiving demodulation circuit 7 reflects the thickness of the sheath S between the substrate 2 and the plasma PL. The receiving demodulation circuit 7 is connected to a calculator 8.

[0069] The calculator 8 receives the at least one signal from the receiving demodulation circuit 7. The calculator 8 is configured to calculate the thickness of the sheath S from the at least one signal received from the receiving demodulation circuit 7. Alternatively, the calculator 8 executes a program stored in a memory 10 to perform the calculation of the thickness of the sheath S. Alternatively, the calculator 8 executes a program stored in the memory 10 to control the transmitting circuit 4 of the measurement unit 3. The calculator 8 can be constituted by a processor such as a CPU.

[0070] In the measurer 1, the elements used to calculate the thickness of the sheath S, i.e., the transmitting circuit 4, the transmitting antenna 5, the at least one receiving antenna 6, the receiving demodulation circuit 7, and the calculator 8 are provided in or on the substrate 2 which can be placed on a substrate support of a plasma processing apparatus. Therefore, by generating the plasma PL in a state where the measurer 1 is placed on the substrate support 104, the thickness of the sheath S can be calculated without installing a dedicated measurement device in the plasma processing apparatus. Further, with the measurer 1, the thickness of the sheath S can be calculated in a state substantially the same as a state in which the substrate W is processed in the plasma processing apparatus. Further, the measurer 1 can be used to measure the thickness of the sheath in any plasma processing apparatus having a substrate support on which the substrate 2 can be placed. Further, the measurer 1 can be easily replaced even if it fails.

[0071] Hereinafter, a method of calculating the thickness of the sheath according to one example embodiment will be described. In the method, the measurer 1 is used. In the following description, the method will be described with the case where the method of calculating the thickness of the sheath is applied to the plasma processing apparatus 100 as an example.

[0072] In this method, first, the measurer 1 is placed on the substrate support 104 in the chamber 102 of the plasma processing apparatus 100. The measurer 1 is transported into the chamber 102 from the end wall of the substrate processing system including the plasma processing apparatus 100 via the transport system, and is placed on the substrate support 104. Then, the measurer 1 is held with the electrostatic chuck 108. Then, the circuit operation of the measurer 1 is started.

[0073] Next, the plasma PL is generated in the chamber of the plasma processing apparatus 100. In order to generate the plasma PL, a gas is supplied from the gas supply portion 110 into the chamber 102. Further, the pressure of the gas in the chamber 102 is adjusted by the exhaust apparatus 112. Then, high-frequency electric power from the high-frequency power supply 114 is supplied to the lower electrode 106. As a result, the plasma PL is generated in the chamber 102 and above the measurer 1.

[0074] In this method, the thickness of the sheath layer S is calculated in the calculator 8 of the measurer 1 using the above-described at least one signal from the reception demodulation circuit 7 while the plasma PL is generated. Then, the supply of the gas by the gas supply portion 110 is stopped, the circuit operation of the measurer 1 is stopped, and the holding of the measurer 1 by the electrostatic chuck 108 is stopped. Then, the measurer 1 is transported from the chamber 102 to the end wall by the transport system.

[0075] Hereinafter, several example embodiments of the measurement section which can be employed as each of one or more measurement sections 3 of the measurer 1 will be described.

[0076] Figure 9 is a diagram showing a measurement section of one example embodiment. Figure 9 The measurement section 3A shown can be employed as each of one or more measurement sections 3 of the measurer 1. In the measurement section 3A, the transmission circuit 4 includes the oscillator 4g of the microwaves and the amplifier 4a. In the measurement section 3A, the transmission circuit 4 outputs the microwaves as the continuous wave to the transmission antenna 5.

[0077] The measurement section 3A includes the reception antennas 61 to 66 as the at least one reception antenna 6. The transmission antenna 5 and the reception antennas 61 to 66 are arranged in the X direction. Further, the number of the reception antennas in the measurement section 3A can be two or more, and can be any number.

[0078] In the measurement section 3A, the reception demodulation circuit 7 includes the first amplifiers 711 to 716, the band-pass filters 721 to 726, the detection diodes 731 to 736, the second amplifiers 741 to 746, and the A / D converters 751 to 756. In the reception demodulation circuit 7 of the measurement section 3A, the number of each of the first amplifiers, the band-pass filters, the detection diodes, the second amplifiers, and the A / D converters is the same as the number of the reception antennas of the measurement section 3A.

[0079] The input terminals of the first amplifiers 711 to 716 are connected to the reception antennas 61 to 66, respectively. The first amplifiers 711 to 716 generate a plurality of amplified signals by amplifying a plurality of reception waves received by the reception antennas 61 to 66, respectively. The first amplifiers 711 to 716 output the generated plurality of amplified signals from their output terminals, respectively.

[0080] The input terminals of the band pass filters 721 to 726 are connected to the output terminals of the first amplifiers 711 to 716, respectively. The pass bands of the band pass filters 721 to 726 are bands in which signals having the same frequency as the frequency of the transmission wave are selectively passed. The band pass filters 721 to 726 generate a plurality of filtered signals by filtering the plurality of amplified signals from the first amplifiers 711 to 716, respectively. The band pass filters 721 to 726 output the generated plurality of filtered signals from their output terminals, respectively.

[0081] The input terminals of the detection diodes 731 to 736 are connected to the output terminals of the band pass filters 721 to 726, respectively. The detection diodes 731 to 736 generate a plurality of detected signals by detecting the plurality of filtered signals from the band pass filters 721 to 726, respectively. The detection diodes 731 to 736 output the generated plurality of detected signals from their output terminals, respectively.

[0082] The input terminals of the second amplifiers 741 to 746 are connected to the output terminals of the detection diodes 731 to 736, respectively. The second amplifiers 741 to 746 generate a plurality of amplified signals by amplifying the plurality of detected signals from the detection diodes 731 to 736, respectively. The second amplifiers 741 to 746 output the generated plurality of amplified signals from their output terminals, respectively.

[0083] The input terminals of the A / D converters 751 to 756 are connected to the output terminals of the second amplifiers 741 to 746, respectively. The A / D converters 751 to 756 generate a plurality of digital signals by performing A / D conversion processing on the plurality of amplified signals from the second amplifiers 741 to 746, respectively. The A / D converters 751 to 756 output the generated plurality of digital signals from their output terminals, respectively. The plurality of digital signals generated by the A / D converters 751 to 756 indicate the intensities of the reception waves of the reception antennas 61 to 66, respectively. The plurality of digital signals generated by the A / D converters 751 to 756 are input to the arithmetic unit 8 as signals reflecting the thickness of the sheath S.

[0084] The arithmetic unit 8 receives a plurality of digital signals from the A / D converters 751 to 756. The arithmetic unit 8 determines the thickness of the sheath S corresponding to the combination of the intensities of the received waves of the respective receiving antennas 61 to 66 determined from the above-described digital signals. Alternatively, the arithmetic unit 8 can hold the relationship between the combination of the intensities of the received waves of the respective receiving antennas 61 to 66 and the thickness of the sheath S as a table or a function in advance. Alternatively, the arithmetic unit 8 can use such a table or a function to calculate the thickness of the sheath S.

[0085] The intensity of the received wave of each of the receiving antennas 61 to 66 depends on the thickness of the sheath S. Therefore, with the measuring section 3A, it is possible to calculate the thickness of the sheath S from the combination of the intensities of the received waves of the respective receiving antennas 61 to 66.

[0086] Hereinafter, the operation of the measuring section 3A will be described with reference to the flowchart shown in FIG. 6. Figure 10 . Figure 10 is a view showing another example of the measuring section. Figure 10 The measuring section 3B shown in FIG. 5 can be employed as each of one or more measuring sections 3 of the measurer 1. In the measuring section 3B, the transmission circuit 4 includes an oscillator 4g of microwaves, a pulse oscillator 4pg, a pulse modulator 4pm, and an amplifier 4a. In the measuring section 3B, the transmission circuit 4 outputs a pulse of microwaves. The pulse oscillator 4pg generates a pulse signal. The pulse modulator 4pm generates a pulse of microwaves by modulating the amplitude of the microwaves from the oscillator 4g using the pulse signal. The amplifier 4a amplifies the pulse of microwaves generated by the pulse modulator 4pm and outputs it to the transmission antenna 5. The transmission antenna 5 emits the amplified pulse of microwaves as a transmission wave.

[0087] The measuring section 3B includes the receiving antennas 61 to 66 as at least one receiving antenna 6. The transmission antenna 5 and the receiving antennas 61 to 66 are arranged along the X direction. Further, the number of the receiving antennas in the measuring section 3B can be one or more, and can be any number.

[0088] The reception demodulation circuit 7 of the measuring section 3B has the same structure as that of the reception demodulation circuit 7 of the measuring section 3A. That is, in the measuring section 3B, the reception demodulation circuit 7 includes the first amplifiers 711 to 716, the bandpass filters 721 to 726, the detection diodes 731 to 736, the second amplifiers 741 to 746, and the A / D converters 751 to 756. In the reception demodulation circuit 7 of the measuring section 3B, the number of each of the first amplifiers, the bandpass filters, the detection diodes, the second amplifiers, and the A / D converters is the same as the number of the receiving antennas of the measuring section 3B.

[0089] In the measurement section 3B, the transmission wave is a pulse of microwaves. Therefore, the reception wave of each of the reception antennas 61 to 66 is also a pulse of microwaves. Therefore, each of the digital signals generated by the A / D converters 751 to 756 also contains a pulse. The pulse in each of the plurality of digital signals generated by the A / D converters 751 to 756 has a delay time with respect to the transmission time of the transmission wave (pulse of microwaves).

[0090] The delay time depends on the thickness of the sheath layer S.

[0091]

[0092] In the measurement section 3B, the arithmetic device 8 receives the plurality of digital signals from the A / D converters 751 to 756. The arithmetic device 8 determines the delay time of the reception time of the plurality of reception waves (i.e., pulses of microwaves) of each of the reception antennas 61 to 66 corresponding to the transmission time of the transmission wave (pulse of microwaves) from the above-described digital signals. The arithmetic device 8 calculates the thickness of the sheath layer S from the above-described delay time. Alternatively, the arithmetic device 8 calculates a plurality of thicknesses corresponding to the above-described delay times and calculates the average of the plurality of thicknesses as the thickness of the sheath layer S. Further, the thickness Sth of the sheath layer S determined from each of the digital signals is calculated in accordance with the following equation (1). In the equation (1), c is the speed of light, t is the delay time, and L is the distance in the X direction between the reception antenna that has received the reception wave having the delay time and the transmission antenna.

[0093] With the measurement section 3B, it is possible to calculate the thickness of the sheath layer S from the delay time of the reception wave using a pulse of microwaves as the transmission wave. Further, alternatively, the transmission wave can not be modulated using the pulse signal from the pulse oscillator 4pg but can be modulated by the TDMA method.

[0094] Hereinafter, the measurement section 3B will be described with reference to Figure 11 . Figure 11 is a view showing another example of the measurement section of the embodiment. Figure 11 The measurement section 3C shown in the view can be employed as each of one or more measurement sections 3 of the measurer 1. In the measurement section 3C, the transmission circuit 4 includes the oscillator 4g of microwaves and the amplifier 4a. In the measurement section 3C, the transmission circuit 4 outputs microwaves that are continuous waves to the transmission antenna 5.

[0095] The measurement section 3C includes one reception antenna 6. The transmission antenna 5 and the reception antenna 6 are arranged in the X direction. Further, the number of reception antennas in the measurement section 3C can be two or more.

[0096] In the measurement section 3C, the reception demodulation circuit 7 includes an amplifier CI, mixers C2 and C3, a local oscillator C4, amplifiers C5 and C6, a phase detector C7, and an A / D converter C8. In the measurement section 3C, the microwave from the oscillator 4g is output to the mixer C2 in addition to the amplifier 4a. The mixer C2 is connected to the local oscillator C4. The mixer C2 generates a first intermediate frequency signal by mixing the microwave from the oscillator 4g and a signal from the local oscillator C4. The output terminal of the mixer C2 is connected to the input terminal of the amplifier C5. The amplifier C5 generates a first amplified signal by amplifying the first intermediate frequency signal. The amplifier C5 outputs the first amplified signal from its output terminal. The output terminal of the amplifier C5 is connected to the first input terminal of the phase detector C7.

[0097] The input terminal of the amplifier CI is connected to the reception antenna 6. The amplifier CI amplifies the reception wave from the reception antenna 6 to generate an amplified signal. The amplifier CI outputs the generated amplified signal from its output terminal. The output terminal of the amplifier CI is connected to the mixer C3. The mixer C3 is connected to the local oscillator C4. The mixer C3 generates a second intermediate frequency signal by mixing the amplified signal from the amplifier CI and a signal from the local oscillator C4. The output terminal of the mixer C3 is connected to the input terminal of the amplifier C6. The amplifier C6 generates a second amplified signal by amplifying the second intermediate frequency signal. The amplifier C6 outputs the second amplified signal from its output terminal. The output terminal of the amplifier C6 is connected to the second input terminal of the phase detector C7.

[0098] The phase detector C7 outputs a voltage having a level corresponding to the phase difference between the first amplified signal and the second amplified signal, i.e., the phase difference between the transmission wave and the reception wave, from its output terminal. The output terminal of the phase detector C7 is connected to the input terminal of the A / D converter C8. The A / D converter C8 generates a digital signal by performing A / D conversion processing on the signal received at the input terminal. The A / D converter C8 outputs the generated digital signal from its output terminal. The digital signal generated by the A / D converter C8 is input to the arithmetic unit 8 as a signal reflecting the thickness of the sheath layer S.

[0099] The arithmetic unit 8 receives the digital signal from the A / D converter C8. The arithmetic unit 8 determines the phase difference between the transmission wave and the reception wave the phase difference in accordance with the calculation. V is the level of the output voltage of the phase detector C7 determined from the digital signal. K is a phase sensitivity constant, which is predetermined. The arithmetic unit 8 calculates the thickness Sth of the sheath layer S in accordance with the calculation of Here, c is the speed of light, and f is the frequency of the transmission wave.

[0100] Further, in a case where the measuring section 3C has a plurality of receiving antennas, the receiving demodulation circuit 7 includes a plurality of sets of the amplifier C1, the mixers C2 and C3, the local oscillator C4, the amplifiers C5 and C6, the phase detector C7, and the A / D converter C8. In this case, the operator 8 can also calculate an average of a plurality of thicknesses as the thickness of the sheath layer S, where the average of the plurality of thicknesses is calculated from the digital signals generated by the A / D converter C8 of each of the plurality of sets.

[0101] Hereinafter, referring to Figure 12 . Figure 12 is a diagram showing a measuring section of another example embodiment. Figure 12 The measuring section 3D shown in FIG. 12 can be employed as each of one or more measuring sections 3 of the measurer 1. In the measuring section 3D, the transmitting circuit 4 includes the oscillator 4g of microwaves, the signal generator 4fg, the modulator 4fm, and the amplifier 4a. In the measuring section 3D, the transmitting circuit 4 outputs microwaves whose frequency is alternately monotonously increased and monotonously decreased. The modulator 4fm generates modulated microwaves by modulating the frequency of the microwaves from the oscillator 4g using the signal from the signal generator 4fg. The amplifier 4a amplifies the modulated microwaves generated by the modulator 4fm and outputs them to the transmitting antenna 5. The transmitting antenna 5 emits the amplified modulated microwaves as a transmission wave.

[0102] The measuring section 3D includes one receiving antenna 6. The transmitting antenna 5 and the receiving antenna 6 are arranged along the X direction. Further, the number of receiving antennas in the measuring section 3D can be two or more.

[0103] In the measuring section 3D, the receiving demodulation circuit 7 has the amplifier D1, the mixer D2, the detection diode D3, the band-pass filter D4, the amplifier D5, and the A / D converter D6. The input terminal of the amplifier D1 is connected to the receiving antenna 6. The amplifier D1 amplifies the reception wave from the receiving antenna 6 and generates an amplified signal. The amplifier D1 outputs the generated amplified signal from its output terminal. The output terminal of the amplifier D1 is connected to the mixer D2. The mixer D2 is connected to the oscillator 4g. The mixer D2 generates a signal having a beat frequency by mixing the amplified signal from the amplifier D1 and the microwaves from the oscillator 4g.

[0104] There is a time difference between the time at which the transmission wave is transmitted and the time at which the reception wave, which is the reflection wave of the transmission wave reflected by the plasma PL, is received by the receiving antenna 6. That is, the reception wave has a delay time. The delay time depends on the thickness of the sheath layer S. The signal obtained by mixing the transmission wave and the reception wave at the same time becomes a signal having a beat frequency corresponding to the delay time of the reception wave. Therefore, the signal generated by the mixer D2 has a beat frequency reflecting the thickness of the sheath layer S.

[0105] The detection diode D3 generates a detection signal in accordance with the signal generated by the mixer D2. The detection diode D3 outputs the detection signal from its output terminal. The output terminal of the detection diode D3 is connected to the input terminal of the band-pass filter D4. The passband of the band-pass filter D4 is a frequency band that selectively passes a signal having the beat frequency. The band-pass filter D4 generates a filtered signal by filtering the detection signal from the detection diode D3. The band-pass filter D4 outputs the generated filtered signal from its output terminal.

[0106] The input terminal of the amplifier D5 is connected to the output terminal of the band-pass filter D4. The amplifier D5 generates an amplified signal by amplifying the filtered signal. The amplifier D5 outputs the generated amplified signal from its output terminal. The input terminal of the A / D converter D6 is connected to the output of the amplifier D5. The A / D converter D6 generates a digital signal by performing A / D conversion processing on the amplified signal from the amplifier D5. The generated digital signal has the beat frequency that reflects the thickness of the sheath layer S.

[0107] The operator 8 receives the digital signal from the A / D converter D6. The operator 8 determines the beat frequency from a frequency spectrum obtained by applying, for example, a high-speed Fourier transform (FFT) to the digital signal. The operator 8 calculates the thickness of the sheath layer S corresponding to the determined beat frequency. Alternatively, the operator 8 can hold a table or a function of the relationship between the beat frequency and the thickness of the sheath layer S in advance. Alternatively, the operator 8 can calculate the thickness of the sheath layer S using such a table or a function.

[0108] Further, in the case where the measurement section 3D has a plurality of reception antennas, the reception demodulation circuit 7 has a plurality of sets of the amplifier Dl, the mixer D2, the detection diode D3, the band-pass filter D4, the amplifier D5, and the A / D converter D6. In this case, the operator 8 can calculate an average of a plurality of thicknesses as the thickness of the sheath layer S, the plurality of thicknesses being calculated from the digital signals generated by the A / D converter D6 of each of the plurality of sets.

[0109] Reference will now be made to Figure 13 . Figure 13 is a diagram showing a measurement section of another example embodiment. Figure 13 The measurement section 3E shown in FIG. 12 can be employed as each of one or more measurement sections 3 of the measurer 1. The measurement section 3E is configured to be able to scan the transmission direction of the transmission wave transmitted from the transmission antenna 5 in such a manner that the angle θ formed by the transmission direction of the transmission wave and the substrate 2 is increased or decreased. In the measurement section 3E, the transmission antenna 5 can have Figure 8 the structure shown in FIG. 13.

[0110] In the measurement section 3E, the transmission circuit 4 has an oscillator 4g of microwaves, an amplifier 4a, a phase shifter group 4p, a signal generator 4d, an amplifier 4b, and an A / D converter 4c. In the transmission circuit 4, the oscillator 4g generates microwaves as continuous waves. The amplifier 4a amplifies the microwaves from the oscillator 4g and outputs to the phase shifter group 4p.

[0111] The phase shifter group 4p contains a plurality of phase shifters as explained with reference to Figure 8 The plurality of phase shifters are applied with the plurality of microwaves from the amplifier 4a respectively. The plurality of microwaves are applied to the plurality of groups of antenna elements of the transmission antenna 5 respectively after a separate phase is applied by each of the plurality of phase shifters of the phase shifter group 4p. The plurality of phase shifters of the phase shifter group 4p change the phase of the microwaves applied to the plurality of groups of transmission antennas of the transmission antenna 5 respectively in synchronization with a reference signal from the signal generator 4d. As a result, the transmission direction of the transmission wave transmitted from the plurality of groups of transmission antennas of the transmission antenna 5 is scanned in a manner that the angle θ of the transmission wave is increased and decreased at a period determined in accordance with the frequency (predetermined frequency) of the reference signal. The reference signal has a frequency lower than the frequency of the microwaves. The frequency of the reference signal is, for example, 1 Hz or more and 1 kHz or less.

[0112] The output of the signal generator 4d is connected to the input of the A / D converter 4c via the amplifier 4b. The reference signal is amplified by the amplifier 4b and input to the A / D converter 4c. The A / D converter 4c generates a digital signal (hereinafter, referred to as "reference digital signal") by only A / D conversion processing of the amplified reference signal. The reference digital signal generated by the A / D converter 4c is applied to the arithmetic unit 8.

[0113] The measurement section 3E contains the reception antennas 61 to 66 as at least one reception antenna 6. The transmission antenna 5 and the reception antennas 61 to 66 are arranged along the X direction. In addition, when the number of reception antennas in the measurement section 3E is one or more, it can be any number.

[0114] The reception demodulation circuit 7 of the measurement section 3E has the same structure as the reception demodulation circuit 7 of the measurement section 3A. That is, in the measurement section 3E, the reception demodulation circuit 7 contains the first amplifiers 711 to 716, the band pass filters 721 to 726, the detection diodes 731 to 736, the second amplifiers 741 to 746, and the A / D converters 751 to 756. However, in the measurement section 3E, the band pass filters 721 to 726 each have a frequency band that selectively passes a component having the same frequency as the frequency of the reference signal. In the reception demodulation circuit 7 of the measurement section 3E, the number of each of the first amplifiers, the band pass filters, the detection diodes, the second amplifiers, and the A / D converters is the same as the number of the reception antennas of the measurement section 3E.

[0115] In the measurement section 3E, the digital signals output from the A / D converters 751 to 756 have phase differences with respect to the reference digital signal. The phase differences depend on the thickness of the sheath S.

[0116] In the measurement section 3E, the calculator 8 receives the plurality of digital signals from the A / D converters 751 to 756. The calculator 8 determines the phase differences of the plurality of digital signals from the A / D converters 751 to 756 with respect to the reference digital signal. The calculator 8 calculates the thickness of the sheath S from the above-mentioned phase differences. Alternatively, the calculator 8 calculates a plurality of thicknesses corresponding to the above-mentioned phase differences, and calculates an average of the plurality of thicknesses as the thickness of the sheath S. Further, the thickness Sth of the sheath S determined from the digital signals from the A / D converters 751 to 756 is calculated in accordance with the above-mentioned equation (1). In the equation (1) used in the calculator 8 of the measurement section 3E, c is the speed of light, t is the phase difference (delay time), and L is the distance between the reception antenna and the transmission antenna for receiving the reception wave corresponding to the digital signal having the phase difference.

[0117] The above-described various exemplary embodiments have been described, but are not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and changes can be made. Further, elements in different embodiments can be combined to form other embodiments.

[0118] According to the above description, various embodiments of the present application have been described in the present specification for the purpose of illustration, and it should be understood that various changes can be made without departing from the scope and spirit of the present application. Therefore, the various embodiments disclosed in the present specification are not limiting, and the true scope and spirit are given by the scope of the claims attached hereto.

Claims

1. A measuring device, characterized by comprises: a substrate capable of being placed on a substrate support of a plasma processing apparatus; a transmission circuit provided in or on the substrate and capable of generating microwaves; a transmission antenna provided in or on the substrate and capable of transmitting the microwaves generated by the transmission circuit as a transmission wave; at least one reception antenna provided in or on the substrate and capable of receiving a reflection wave of the transmission wave reflected by a plasma above the substrate support as at least one reception wave; a reception demodulation circuit provided in or on the substrate and capable of generating at least one signal reflecting a thickness of a sheath layer between the substrate and the plasma from the at least one reception wave; and a calculator provided in or on the substrate and capable of calculating the thickness from the at least one signal.

2. The measurer according to claim 1, wherein: as the at least one reception antenna, a plurality of reception antennas are provided, the plurality of reception antennas are arranged in a direction component parallel to the substrate in a direction of transmission of the transmission wave, the reception demodulation circuit is capable of generating a plurality of signals indicating intensities of a plurality of reception waves respectively received by the plurality of reception antennas, the calculator is capable of calculating the thickness from the plurality of signals.

3. The measurer according to claim 1, wherein: the transmission antenna transmits a pulse of the microwaves output from the transmission circuit as the transmission wave, the reception demodulation circuit is capable of generating the at least one signal indicating an intensity of the at least one reception wave, the calculator is capable of calculating a delay time of the at least one reception wave with respect to the transmission wave from the at least one signal, and calculating the thickness from the delay time.

4. The measurer according to claim 3, wherein: as the at least one reception antenna, a plurality of reception antennas are provided, the plurality of reception antennas are arranged in a direction component parallel to the substrate in a direction of transmission of the transmission wave, the reception demodulation circuit is capable of generating a plurality of signals indicating intensities of a plurality of reception waves respectively received by the plurality of reception antennas, the calculator is capable of calculating a plurality of delay times of the plurality of reception waves with respect to the transmission wave from the plurality of signals, and calculating the thickness from the plurality of delay times.

5. The measurer according to claim 1, wherein: the reception demodulation circuit is capable of generating the at least one signal indicating a phase difference between the transmission wave and the at least one reception wave.

6. The measurer according to claim 1, wherein: the transmission circuit is capable of alternately monotonously increasing and monotonously decreasing a frequency of the transmission wave, the reception demodulation circuit is capable of mixing the transmission wave and the at least one reception wave to generate an intermediate frequency signal having a beat frequency reflecting the thickness of the sheath layer as the at least one signal.

7. The measurer according to claim 1, wherein: ​ The transmission circuit is capable of scanning the transmission direction of the transmission wave in a manner that the angle formed by the transmission direction of the transmission wave and the substrate is increased or decreased in synchronization with a reference signal having a prescribed frequency lower than the frequency of the transmission wave. The reception / demodulation circuit is capable of generating a signal of a component of the prescribed frequency included in the at least one reception wave as the at least one signal. The arithmetic unit is capable of calculating the thickness from a phase difference between the reference signal and the at least one signal.

8. The measurer according to any one of claims 1 to 7, wherein: The transmission wave is a millimeter wave.

9. A method of determining the thickness of a sheath layer, characterized by, including: a) a step of loading a measurer on a substrate support in a chamber of a plasma processing apparatus, the measurer including: a substrate capable of being loaded on the substrate support of the plasma processing apparatus; a transmission circuit provided in or on the substrate and capable of generating a microwave; a transmission antenna provided in or on the substrate and capable of transmitting the microwave generated by the transmission circuit as a transmission wave; at least one reception antenna provided in or on the substrate and capable of receiving a reflection wave of the transmission wave reflected by plasma above the substrate support as at least one reception wave; a reception / demodulation circuit provided in or on the substrate and capable of generating at least one signal reflecting a thickness of a sheath layer between the substrate and the plasma from the at least one reception wave; and an arithmetic unit provided in or on the substrate and capable of calculating the thickness from the at least one signal; b) a step of generating plasma in the chamber of the plasma processing apparatus; and c) a step of calculating the thickness from the at least one signal in the arithmetic unit of the measurer loaded on the substrate support while the plasma is generated in the chamber.

Images