Temperature sensor and plasma processing device

Abstract

The present application provides a temperature sensor and a plasma processing apparatus capable of providing a technique that can reduce high-frequency noise generated when plasma is generated. A temperature sensor of one embodiment of the present disclosure is a temperature sensor that measures the temperature in a processing container in which plasma processing is performed, and includes a thermocouple having a temperature measuring contact in the processing container, a protection tube for housing and protecting the thermocouple, and an electromagnetic shield provided in the protection tube so as to cover the thermocouple.

Description

Technical Field

[0001] This disclosure relates to a temperature sensor and a plasma processing apparatus. Background Technology

[0002] Regarding plasma processing apparatuses, the following technique is known: a noise removal filter is connected to a compensating wire connected to a thermocouple, and a shielding member is assembled to cover the compensating wire. The thermocouple is used to detect the temperature inside the reaction tube (e.g., see Patent Document 1). In this technique, the noise removal filter and the shielding member are disposed outside the reaction tube.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-151081 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] This disclosure provides a technique for reducing high-frequency noise generated during plasma generation.

[0008] Solution for solving the problem

[0009] One aspect of the plasma processing apparatus disclosed herein is a temperature sensor for measuring the temperature within a processing container used for plasma processing. The temperature sensor comprises: a thermocouple having temperature-sensing contacts within the processing container; a protective tube for housing and protecting the thermocouple; and an electromagnetic shield disposed within the protective tube in a manner that covers the thermocouple.

[0010] The effects of the invention

[0011] According to this disclosure, it is possible to reduce high-frequency noise generated during plasma generation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating an example of a plasma processing apparatus according to an embodiment.

[0013] Figure 2 yes Figure 1 Sectional view II-II.

[0014] Figure 3 This is a diagram showing an example of an internal temperature sensor.

[0015] Figure 4 yes Figure 3 Sectional view IV-IV.

[0016] Figure 5It is a diagram used to illustrate the wire diameter and mesh opening of metal mesh.

[0017] Figure 6 This is a graph showing the measurement results of the shielding effect of the metal mesh.

[0018] Figure 7 This is a diagram illustrating an example of output variation in a temperature sensor caused by high-frequency noise.

[0019] Explanation of reference numerals in the attached figures

[0020] 1: Plasma processing device; 10: Processing container; 70: Internal temperature sensor; 71: Thermocouple; 71a: Temperature measuring contact; 72: Insulating component; 73: Protective tube; 74: Metal mesh. Detailed Implementation

[0021] Hereinafter, non-limiting illustrative embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the drawings, the same or corresponding components or parts are labeled with the same or corresponding reference numerals, and repeated descriptions are omitted.

[0022] [Plasma Processing Device]

[0023] Reference Figure 1 and Figure 2 An example of the plasma processing apparatus of the embodiment will be described. Figure 1 This is a schematic diagram illustrating an example of a plasma processing apparatus according to an embodiment. Figure 2 yes Figure 1 Sectional view II-II.

[0024] The plasma processing apparatus 1 includes a processing container 10, a gas supply unit 20, a plasma generation unit 30, an exhaust unit 40, a heating unit 50, an external temperature sensor 60, an internal temperature sensor 70, and a control unit 90.

[0025] The processing container 10 has a longitudinal cylindrical shape with an opening at the lower end and a top. The entire processing container 10 is made of, for example, quartz. At the opening at the lower end of the processing container 10, a cylindrical metal manifold 11 is connected via a sealing member (not shown).

[0026] The manifold 11 supports the lower end of the processing container 10, and a crystal boat 12, in which multiple substrates W are arranged in multiple layers (e.g., 25 to 150), is inserted into the processing container 10 from below the manifold 11. In this way, multiple substrates W are arranged substantially horizontally within the processing container 10 with spacing between them in the vertical direction. The substrates W are, for example, semiconductor wafers.

[0027] The crystal boat 12 is made of quartz, for example. The crystal boat 12 has three supports 12a, which support multiple substrates W through grooves (not shown) formed in the supports 12a. The crystal boat 12 is supported on the rotation shaft 14 via an insulation cylinder 13.

[0028] The insulation cylinder 13 is made of quartz, for example. The insulation cylinder 13 suppresses heat loss from the opening at the lower end of the processing container 10.

[0029] The rotating shaft 14 extends through the cover 15. A magnetic fluid seal (not shown) is provided at the through portion of the rotating shaft 14, which airtightly seals the rotating shaft 14 and supports it in a rotatable manner. The rotating shaft 14 is mounted at the front end of an arm supported by a lifting mechanism (not shown) such as a crystal boat lift, and the crystal boat 12 and the cover 15 are raised and lowered integrally, inserting and disengaging relative to the processing container 10.

[0030] The cover 15 is made of metal, for example. The cover 15 opens and closes to the opening at the lower end of the manifold 11. A sealing member (not shown) is provided between the periphery of the cover 15 and the lower end of the manifold 11 to maintain the airtightness of the processing container 10.

[0031] The exhaust port 16 is located on the lower part of the side wall of the processing container 10 facing the gas nozzle 21, and the processing container 10 is evacuated through the exhaust port 16.

[0032] The gas supply unit 20 supplies various gases to the processing container 10. The gas supply unit 20 has, for example, two gas nozzles 21 and 22. However, the gas supply unit 20 may also have other gas nozzles in addition to the two gas nozzles 21 and 22.

[0033] The gas nozzle 21, for example, is formed of quartz and has an L-shape that bends upward and extends vertically after penetrating the inner side of the sidewall of the manifold 11. The vertical portion of the gas nozzle 21 is disposed within the processing container 10. The gas nozzle 21 is connected to a supply source 26 for dichlorosilane (DCS; SiH2Cl2) gas. In the vertical portion of the gas nozzle 21, a plurality of gas holes 21h are formed at intervals along a length corresponding to the wafer support range of the boat 12 in the vertical direction. Each gas hole 21h faces, for example, the center C of the processing container 10, and ejects DCS gas horizontally toward the center C of the processing container 10. However, each gas hole 21h may also face other directions, for example, it may face a direction at an angle to the direction of the center C of the processing container 10, or it may face the inner wall side of the nearby processing container 10.

[0034] The gas nozzle 22, for example, is formed of quartz and has an L-shape that bends upward below the plasma dividing wall 34, penetrates to the inner side of the lower part of the plasma dividing wall 34, and extends vertically upward. The vertical portion of the gas nozzle 22 is disposed in the plasma generation space P. The gas nozzle 22 is connected to an ammonia (NH3) supply source 27. In the vertical portion of the gas nozzle 22, a plurality of gas holes 22h are formed at intervals along a length corresponding to the wafer support range of the crystal boat 12 in the vertical direction. Each gas hole 22h faces, for example, the center C of the processing container 10, and ejects ammonia gas horizontally toward the center C of the processing container 10. However, each gas hole 22h may also face other directions, for example, it may face a direction that is at an angle to the direction of the center C of the processing container 10.

[0035] In addition, gas nozzles 21 and 22 are connected to a purge gas supply source (not shown), and purge gas is ejected into the processing container 10 from each gas port 21h and 22h. The purge gas can be, for example, an inert gas such as argon (Ar) or nitrogen (N2). Furthermore, gas nozzle 21 can also be connected to a supply source of other gases used to generate plasma, such as hydrogen (H2) or chlorine (Cl2). Additionally, gas nozzle 22 can also be connected to a supply source of other raw material gases, such as silicon raw material gas (different from the DCS gas) or metal-containing gas.

[0036] A plasma generation unit 30 is formed on a portion of the sidewall of the processing container 10. The plasma generation unit 30 plasmaizes ammonia gas supplied from the gas nozzle 22 to generate active species. The plasma generation unit 30 includes an RF power supply 31, a matching circuit 32, a plasma partition wall 34, a plasma electrode 35, an insulating protective cover 37, and a power supply line 38.

[0037] The RF power supply 31 is connected to the lower end of the plasma electrode 35 via the power supply line 38, applying RF power of a specified frequency to the plasma electrode 35. The specified frequency may be, for example, 13.56MHz, 27.12MHz, or 40.68MHz.

[0038] Matching circuit 32 is disposed between RF power supply 31 and plasma electrode 35 in power supply line 38. Matching circuit 32 controls the impedance of the plasma side when viewed from the RF power supply 31 side. Matching circuit 32 includes a coil and a capacitor (variable capacitor), and the capacitance of the variable capacitor is adjusted to minimize the power of the reflected wave, thereby performing matching. Matching circuit 32 can be, for example, an L-shaped matching circuit or a π-shaped matching circuit.

[0039] The plasma partition wall 34 is hermetically welded to the outer wall of the processing container 10. The plasma partition wall 34 is formed, for example, by quartz. The plasma partition wall 34 has a concave cross-section and covers the opening 17 formed in the side wall of the processing container 10. The opening 17 is formed elongated in the vertical direction so as to cover all the substrates W supported by the crystal boat 12 in the vertical direction. A gas nozzle 22 is provided in the inner space, i.e., the plasma generation space P, defined by the plasma partition wall 34 and communicating with the inside of the processing container 10. The gas nozzle 22 is used to spray ammonia gas as a plasma generation gas.

[0040] The plasma electrode 35 includes a pair of electrodes 35a and 35b. Each electrode 35a and 35b is an elongated plate-like structure with its length extending vertically. The electrodes 35a and 35b are arranged facing each other on the outer surfaces of the plasma partition wall 34 on both sides of the wall. A power supply line 38 is connected to the lower end of each electrode 35a and 35b, and RF power from the RF power supply 31 is applied to the lower end of each electrode 35a and 35b via a matching circuit 32.

[0041] An insulating protective cover 37 is mounted on the outside of the plasma partition wall 34 in a manner that covers the plasma electrode 35. The insulating protective cover 37 is formed, for example, of an insulator such as quartz.

[0042] Power supply line 38 electrically connects RF power supply 31 to plasma electrode 35.

[0043] The exhaust section 40 performs vacuum exhaust on the processing container 10 via the exhaust port 16. The exhaust section 40 includes an exhaust pipe 41 and an exhaust device 42. The exhaust pipe 41 is connected to the exhaust port 16. The exhaust device 42 includes a pressure control valve, a vacuum pump, etc.

[0044] The heating unit 50 heats the substrate W housed within the processing container 10. The heating unit 50 includes a heater chamber 51 and heater wires 52. The heater chamber 51 is cylindrical with a top and is arranged to surround the outer periphery of the processing container 10. The heater wires 52 are spirally arranged on the inner surface of the heater chamber 51.

[0045] The external temperature sensor 60 is a temperature sensor for measuring the temperature outside the processing container 10. The external temperature sensor 60 has 5 sets of thermocouples 61 and 5 through-tubes 62. The 5 sets of thermocouples 61 and 5 through-tubes 62 are arranged at intervals in the vertical direction of the processing container 10.

[0046] The front end of each thermocouple 61, i.e. the temperature measuring contact 61a, is located outside the processing container 10 and inside the heater chamber 51. The other end of each thermocouple 61 passes through the insertion tube 62 and is led out to the outside of the heater chamber 51.

[0047] Each insertion tube 62 penetrates the side wall of the heater chamber 51 and is arranged approximately horizontally. A thermocouple 61 is inserted into each insertion tube 62 to protect the thermocouple 61. Each insertion tube 62 is, for example, made of quartz.

[0048] The internal temperature sensor 70 is a temperature sensor used to measure the temperature inside the processing container 10 for plasma processing. Details of the internal temperature sensor 70 will be described later.

[0049] The control unit 90 controls each part of the plasma processing apparatus 1. The control unit 90 can be, for example, a computer. Furthermore, the computer program that performs the operations of each part of the plasma processing apparatus 1 is stored on a storage medium. The storage medium can be, for example, a floppy disk, optical disk, hard disk, flash memory, DVD, etc.

[0050] [Internal temperature sensor]

[0051] Reference Figures 1 to 7 An example of the internal temperature sensor 70 will be described. Figure 3 This is a diagram showing an example of an internal temperature sensor 70. Figure 4 yes Figure 3 Sectional view IV-IV. Furthermore, for ease of explanation, in Figure 1 and Figure 2 The solid line in the middle represents thermocouple 71, which consists of two thermocouples in a group.

[0052] An internal temperature sensor 70 measures the temperature inside the processing container 10. The internal temperature sensor 70 has 5 thermocouples 71, 5 insulating components 72, a protective tube 73, a metal mesh 74, a wire shield 75, a relay terminal block 76, a noise filter 77, a temperature controller 78, and a compensating wire 79.

[0053] The front end, i.e., the temperature-sensing contact 71a, of each of the five sets of thermocouples 71 is disposed inside the processing container 10. The temperature-sensing contacts 71a of the five sets of thermocouples 71 are arranged at different heights in the vertical direction of the processing container 10. This allows for the measurement of the temperature at different heights within the processing container 10. The other end of each thermocouple 71 passes through a protective tube 73 and is led out from the inside of the processing container 10 to the outside, where it is connected to a relay terminal block 76 connected to a temperature controller 78. Thus, the temperature of the temperature-sensing contact 71a of each thermocouple 71, i.e., the temperature inside the processing container 10, can be measured by the temperature controller 78.

[0054] Five insulating members 72 are respectively provided corresponding to five sets of thermocouples 71. Each insulating member 72 is disposed between each thermocouple 71 and the metal mesh 74, covering each thermocouple 71. This prevents each thermocouple 71 from direct contact with the metal mesh 74. Each insulating member 72 is formed of an insulator such as quartz.

[0055] The protective tube 73 has an L-shape, extending vertically and curving upwards from the inner sidewall of the manifold 11. That is, one end of the protective tube 73, including the vertical portion, is located inside the processing container 10, and the other end, including the horizontal portion, is located outside the processing container 10. The interior of the protective tube 73 is atmospheric, and it houses five sets of thermocouples 71, five insulating members 72, and a metal mesh 74 for protection. The temperature-sensing contacts 71a of the five sets of thermocouples 71 are arranged in the vertical portion of the protective tube 73. The protective tube 73 is, for example, formed of quartz.

[0056] A metal mesh 74 is disposed within the protective tube 73 to suppress high-frequency noise generated by the five sets of thermocouples 71 during plasma generation. This suppresses the rise in electromotive force of the thermocouples 71 due to the high-frequency noise, thus preventing fluctuations in the output value of the internal temperature sensor 70 relative to its normal output value. The metal mesh 74 is preferably disposed in such a way that it covers at least the temperature-sensing contacts 71a of each of the five sets of thermocouples 71, for example, covering all of the five sets of thermocouples 71. The metal mesh 74 is grounded via a lead 74a that passes through the other end of the protective tube 73 and is led out to the outside of the processing container 10. The lead 74a is fixed to a reference potential point, for example, by screws. Since the metal mesh 74 is disposed within the protective tube 73, the environment in which the metal mesh 74 is disposed is atmospheric. Therefore, the metal mesh 74 is preferably formed of a material with oxidation resistance. Furthermore, since the environment in which the protective tube 73 is disposed reaches a high temperature (e.g., 900°C), the environment in which the metal mesh 74 is disposed is a high-temperature environment. Therefore, the metal mesh 74 is preferably formed of a heat-resistant material. For example, a nickel alloy can be suitably used as such a material.

[0057] Furthermore, preferably, the metal mesh 74 has an electric field shielding effect of 40 dB or more and a magnetic field shielding effect of 20 dB or more against 27 MHz electromagnetic waves. The shielding effect is measured using the KEC method developed by the KEC Kansai Electronics Industry Promotion Center. Additionally, from the viewpoint of easy installation within the protective tube 73, the metal mesh 74 preferably has a highly flexible and easily processed mesh, such as... Figure 5 As shown, a mesh with a wire diameter d of 0.1 mm and a mesh opening A of 0.323 mm is preferred. Furthermore, Figure 5This diagram illustrates the wire diameter d and mesh opening A of the metal mesh 74. Furthermore, when measuring the shielding effect of a metal mesh 74 with a wire diameter d of 0.1 mm and a mesh opening A of 0.323 mm, as... Figure 6 As shown, it has an electric field shielding effect of over 40dB and a magnetic field shielding effect of over 20dB for 27MHz electromagnetic waves. Furthermore, Figure 6 This is a graph showing the measurement results of the shielding effect of the metal mesh 74. The horizontal axis represents the frequency of the electromagnetic wave [MHz], and the vertical axis represents the shielding effect [dB]. Figure 6 In the diagram, the circle indicates the electric field shielding effect, and the triangle indicates the magnetic field shielding effect.

[0058] A wire shield 75 is disposed outside the processing container 10, covering all five sets of thermocouples 71. The wire shield 75 can be, for example, a metal conduit covering the outer portion of the processing container 10 containing the five sets of thermocouples 71. The wire shield 75 suppresses high-frequency noise generated by the five sets of thermocouples 71 during plasma generation. This suppresses the rise in electromotive force of the thermocouples 71 due to this high-frequency noise, thus suppressing fluctuations in the output value of the internal temperature sensor 70 relative to its normal output value. The wire shield 75 is grounded, for example, via a wire clamp 75a, at one or more locations between the protective tube 73 and the relay terminal block 76. Furthermore, in Figure 3 In the example, the wire shield 75 is grounded at two locations between the protection tube 73 and the relay terminal block via wire clamp 75a.

[0059] A relay terminal block 76 is disposed between the five sets of thermocouples 71 and the temperature controller 78. The relay terminal block 76 connects the other end of the five sets of thermocouples 71 to the compensating wire 79 connected to the temperature controller 78.

[0060] A noise filter 77 is disposed between the relay terminal block 76 in the compensating conductor 79 and the temperature controller 78. The noise filter 77 removes high-frequency noise generated by the five sets of thermocouples 71 during plasma generation. The noise filter 77 includes, for example, a ferrite core and a capacitor.

[0061] Temperature controller 78 measures the temperature at the temperature measuring contact 71a of each thermocouple 71, that is, the temperature inside the processing container 10.

[0062] The compensation wire 79 connects the relay terminal block 76 to the temperature controller 78.

[0063] As explained above, in the internal temperature sensor 70 according to the embodiment, a metal mesh 74 is provided inside a protective tube 73 that includes the interior of the processing container 10, covering the thermocouples 71. This suppresses high-frequency noise generated by the five sets of thermocouples 71 during plasma generation without significantly reducing the responsiveness of temperature measurement. As a result, the increase in electromotive force of the thermocouples 71 due to this high-frequency noise is suppressed, thus preventing fluctuations in the output value of the internal temperature sensor 70 relative to its normal output value.

[0064] Furthermore, according to the embodiment, the internal temperature sensor 70 has a metal mesh 74 added inside the protective tube 73 to cover the thermocouple 71. This allows for almost no change to the shape and size of the currently used thermocouple 71, insulating member 72, protective tube 73, etc. Additionally, no changes to the design of the processing container 10 are required. Therefore, no significant increase in cost is incurred.

[0065] Figure 7 This diagram illustrates an example of output variation in a temperature sensor caused by high-frequency noise, showing the output variation of an internal temperature sensor in the case where ammonia plasma is generated by RF power at a frequency of 27 MHz. Figure 7 In the diagram, the horizontal axis represents time, the first (left) vertical axis represents temperature [°C], and the second (right) vertical axis represents RF power [W]. For example... Figure 7 As shown, when the RF power is switched from off to on (200W), the output values ​​(temperatures) of the three internal temperature sensors with temperature-sensing contacts in the upper (TOP), central (CTR), and lower (BTM) sections of the processing container 10 all increase in vertical direction. Specifically, it is observed that there is a 0.7°C difference between the output value of the internal temperature sensor with the temperature-sensing contact in the central (CTR) section when the RF power is on and the output value when the RF power is off. This is considered to be due to the increase in the electromotive force of the thermocouples of the internal temperature sensors caused by the high-frequency noise generated during plasma generation.

[0066] Furthermore, in the above-described embodiments, the metal mesh 74 is an example of an electromagnetic shielding component.

[0067] It should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. The above embodiments may be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit.

[0068] In the above embodiments, the case where the processing container is a single-tube structure has been described, but this disclosure is not limited thereto. For example, the processing container may also be a double-tube structure.

[0069] The above embodiments describe a batch processing apparatus that processes multiple wafers at a time, but this disclosure is not limited to this. For example, the processing apparatus may also be a monolithic apparatus that processes wafers one by one. Alternatively, the processing apparatus may also be a semi-batch processing apparatus that processes multiple wafers disposed on a rotating stage within a processing container by rotating the wafers and passing them sequentially through a region supplying a first gas and a region supplying a second gas.

[0070] In the above embodiments, the case where the substrate is a semiconductor wafer has been described, but this disclosure is not limited thereto. For example, the substrate may also be a large substrate for a flat panel display (FPD), a substrate for an organic EL panel, or a substrate for a solar cell.

Claims

1. A temperature sensor for measuring the temperature inside a processing container used for plasma processing, said temperature sensor having: Thermocouple, which has temperature-sensing contacts inside the processing container; A protective tube, used to house and protect the thermocouple; and An electromagnetic shielding element is disposed inside the protective tube in a manner that covers the thermocouple. in, The electromagnetic shielding component provides an electric field shielding effect of over 40 dB and a magnetic field shielding effect of over 20 dB against 27 MHz electromagnetic waves. One end of the protective tube is located inside the processing container, and the other end is located outside the processing container. The electromagnetic shielding element is led out to the outside of the processing container and grounded after passing through the other end of the protective tube. The electromagnetic shielding is configured to at least cover the temperature measuring contact. The electromagnetic shielding component is formed of a metal mesh. The metal mesh is made of a nickel alloy. The temperature sensor also includes an insulating component disposed between the thermocouple and the electromagnetic shielding component. The protective tube contains a plurality of the thermocouples. The electromagnetic shielding is configured to cover all of the multiple thermocouples.

2. The temperature sensor according to claim 1, wherein, The electromagnetic shielding is arranged to cover the entire thermocouple.

3. A plasma processing apparatus, comprising: Processing container for plasma processing; and A temperature sensor measures the temperature inside the processing container. in, The temperature sensor has the following characteristics: Thermocouple, which has temperature-sensing contacts inside the processing container; A protective tube, used to house and protect the thermocouple; and An electromagnetic shielding element is disposed inside the protective tube in a manner that covers the thermocouple. The electromagnetic shielding component provides an electric field shielding effect of over 40 dB and a magnetic field shielding effect of over 20 dB against 27 MHz electromagnetic waves. One end of the protective tube is located inside the processing container, and the other end is located outside the processing container. The electromagnetic shielding element is led out to the outside of the processing container and grounded after passing through the other end of the protective tube. The electromagnetic shielding is configured to at least cover the temperature measuring contact. The electromagnetic shielding component is formed of a metal mesh. The metal mesh is made of a nickel alloy. The temperature sensor also includes an insulating component disposed between the thermocouple and the electromagnetic shielding component. The protective tube contains a plurality of the thermocouples. The electromagnetic shielding is configured to cover all of the multiple thermocouples.

4. The plasma processing apparatus according to claim 3, wherein, The processing container is cylindrical, and multiple substrates are housed in multiple layers inside the processing container.

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