JP7658779B2 - Plasma Processing Equipment - Google Patents

Description

An embodiment of the present invention relates to a plasma processing apparatus.

In a plasma processing apparatus used for dry etching, etc., the end point of the plasma processing is detected based on a change in the emission spectrum of the plasma (for example, see Patent Document 1).
However, changes in the emission spectrum of the plasma and changes in the scattering intensity of the light irradiated onto the surface of the workpiece result in changes in light over a relatively wide range, and therefore the intensity of the light incident on the sensor that detects the end point is the average value of the light intensity over a relatively wide range, making it difficult to detect slight changes on the surface of the workpiece.

Also, a technique has been proposed in which a sensor is provided on the side of a chamber and detection light is made incident on a detection position from a direction inclined with respect to the surface of the workpiece (see, for example, Patent Document 2).
However, if a sensor is provided on the side of the chamber and the detection light is incident on the detection position from a direction inclined with respect to the surface of the workpiece, the irradiation area of the detection light at the detection position becomes large, and when the irradiation area of the detection light becomes large, information about the surroundings of the detection position is mixed in, making it difficult to detect slight changes at the detection position.

In addition, when a sensor is provided on the side of the chamber, a window must be provided in the side wall of the chamber to allow the detection light to pass through. However, because the side wall of the chamber is provided with a nozzle for supplying gas into the chamber, a load lock chamber, and the like, the location where the window can be installed is limited. Also, considering the airtightness of the chamber, a large window cannot be installed. If the location where the window can be installed is limited or if a large window cannot be installed, it becomes difficult to change the detection position.

Therefore, there was a need to develop a plasma processing device that could accurately detect changes in the detection position and that could change the detection position.

JP 2007-66935 A Japanese Patent Application Publication No. 7-58081

The problem that the present invention aims to solve is to provide a plasma processing apparatus that can accurately detect changes in the detection position and that allows the detection position to be changed.

The plasma processing apparatus according to the embodiment includes a chamber capable of maintaining an atmosphere reduced in pressure below atmospheric pressure, a gas supply unit capable of supplying gas to the inside of the chamber, a mounting table provided inside the chamber on which a workpiece can be placed, a pressure reduction unit capable of reducing the pressure inside the chamber, a window provided in the chamber facing the mounting table, a plasma generation unit provided outside the chamber on the opposite side of the window from the mounting table and capable of generating plasma inside the chamber, a light projection unit capable of irradiating light onto the surface of the workpiece through the window, and a light receiving unit capable of receiving the reflected light reflected by the surface of the workpiece and emitted through the window. The periphery of the window is provided with a first inclined surface inclined with respect to the central axis of the window, and a second inclined surface inclined with respect to the central axis of the window and inclined in the opposite direction to the first inclined surface. The light projection unit faces the first inclined surface. The light receiving unit faces the second inclined surface.

According to an embodiment of the present invention, a plasma processing apparatus is provided that can accurately detect changes in the detection position and can change the detection position.

1 is a schematic cross-sectional view illustrating a plasma processing apparatus according to an embodiment of the present invention. 10A to 10C are schematic cross-sectional views for illustrating a detection unit according to a comparative example. 13A and 13B are schematic cross-sectional views for illustrating a detection portion according to another comparative example. 4 is a schematic cross-sectional view illustrating a light projecting portion, a light receiving portion, an inclined surface, and an inclined surface. FIG. 1 is a schematic plan view illustrating a light projecting portion, a light receiving portion, an inclined surface, and an inclined surface. FIG. 11A to 11C are schematic cross-sectional views for illustrating a change in the detection position. 1 is a schematic diagram illustrating a moving portion; 8 is a schematic diagram of the moving part in FIG. 7 as viewed from the X direction. 11 is a schematic diagram for illustrating a guide. FIG. 11 is a schematic diagram for illustrating a guide. FIG. 11 is a schematic diagram of the guide in FIG. 10 as viewed from the Z direction. FIG. 1A to 1C are schematic diagrams illustrating the case. 1 is a schematic diagram illustrating a plurality of moving parts; 10A to 10C are schematic diagrams for illustrating the configuration of a cover corresponding to a second cover. 13 is a schematic side view illustrating a cover moving portion. FIG. 11 is a schematic perspective view illustrating a cover moving portion. FIG. 1A and 1B are schematic plan views illustrating a jig used for window maintenance. FIG. 1 is a schematic diagram illustrating the installation of windows.

Hereinafter, an embodiment will be described with reference to the drawings. In the drawings, like elements are designated by like reference numerals and detailed description thereof will be omitted as appropriate.
In each drawing, the arrows X, Y, and Z represent three directions perpendicular to each other. For example, the arrows X and Y represent the horizontal direction, and the arrow Z represents the vertical direction.

In the following, as an example, a dual frequency plasma processing apparatus having an inductively coupled electrode in the upper part and a capacitively coupled electrode in the lower part will be exemplified.
However, the method of generating plasma is not limited to this. For example, the plasma processing apparatus may be a plasma processing apparatus using inductively coupled plasma (ICP) or a plasma processing apparatus using capacitively coupled plasma (CCP).

Furthermore, the present invention is not limited to a plasma processing apparatus that generates plasma using high frequency waves, but may be, for example, a plasma processing apparatus that generates plasma using microwaves.
That is, the plasma processing apparatus 1 according to this embodiment may have a window that faces a stage on which an object to be processed is placed and that allows an electromagnetic field to pass through.

Note that known technology can be applied to the general configuration of plasma processing equipment using inductively coupled plasma, capacitively coupled plasma, and microwave plasma, so detailed descriptions of these plasma processing equipment are omitted.

The object 100 to be processed by the plasma processing apparatus 1 according to this embodiment can be, for example, a photomask, a mask blank, a wafer, a glass substrate, etc. However, the object 100 to be processed is not limited to the examples given, and may be any object having a portion to be processed by radicals or ions generated by exciting and activating gas G, which will be described later, with plasma.

Figure 1 is a schematic cross-sectional view illustrating a plasma processing apparatus 1 according to the present embodiment. As shown in Figure 1, the plasma processing apparatus 1 can be provided with a chamber 2, a power supply unit 3, a power supply unit 4, a pressure reduction section 5, a gas supply section 6, a mounting table 7, a detection section 8, and a controller 9.

The controller 9 has, for example, a calculation unit such as a CPU (Central Processing Unit) and a storage unit such as a memory. The controller 9 can be, for example, a computer. The controller 9 controls the operation of each element provided in the plasma processing device 1 based on a control program stored in the storage unit. Note that since known technology can be applied to the control program that controls the operation of each element, a detailed description will be omitted.

The chamber 2 has an airtight structure capable of maintaining an atmosphere at a reduced pressure below atmospheric pressure. The chamber 2 has, for example, a substantially cylindrical shape. The chamber 2 can be made of, for example, a metal such as an aluminum alloy. The chamber 2 can be grounded.

A hole 2a can be provided in the side wall of the chamber 2 for loading and unloading the workpiece 100. A load lock chamber 21 can be connected to the part of the chamber 2 where the hole 2a is provided. A gate valve 22 can be provided in the load lock chamber 21. When performing plasma processing, the hole 2a is closed airtight by the gate valve 22. When loading and unloading the workpiece, the gate valve 22 connects the hole 2a to the load lock chamber 21.

A window 23 is provided in the ceiling of the chamber 2 so as to be airtight. The window 23 faces the mounting table 7 (electrostatic chuck 71) on which the workpiece 100 is placed. The window 23 has a plate shape. The window 23 is capable of transmitting an electromagnetic field. The window 23 can be made of a material that is not easily damaged during plasma processing. The window 23 can be made of a dielectric material such as quartz, for example.

The power supply unit 3 generates plasma P in the internal space of the chamber 2. The power supply unit 3 is provided outside the chamber 2, on the opposite side of the window 23 from the mounting table 7. In the plasma processing apparatus 1, the power supply unit 3 serves as a plasma generating section capable of generating plasma P inside the chamber 2.

The power supply unit 3 includes, for example, an antenna 31 , a matching box 32 , and a power supply 33 .
The antenna 31 can be provided outside the chamber 2 and on the window 23. The antenna 31 is electrically connected to a power source 33 via a matching unit 32. The antenna 31 can have, for example, a plurality of coils that generate an electromagnetic field and a plurality of capacitors. In addition, a cover 34 that covers the antenna 31 and the window 23 can be further provided. The cover 34 can be made of metal and can be grounded. In addition, a Faraday shield can be further provided between the antenna 31 and the window 23.

The matching device 32 may include a matching circuit for matching the impedance on the power supply 33 side with the impedance on the plasma P side.

The power source 33 can be a high-frequency power source. The power source 33 applies high-frequency power having a frequency of, for example, about 100 KHz to 100 MHz to the antenna 31. In this case, the power source 33 applies high-frequency power having a frequency suitable for generating plasma P (for example, 13.56 MHz) to the antenna 31. The power source 33 can also be one that changes the frequency of the high-frequency power it outputs.

The power supply unit 4 is provided for so-called bias control. That is, the power supply unit 4 is provided to control the energy of the ions drawn into the workpiece 100. In this case, if the energy of the ions drawn into the workpiece 100 is increased, the sputtering effect caused by the ions becomes more likely to occur. Also, if the energy of the ions drawn into the workpiece 100 is decreased, chemical processing by radicals becomes more likely to occur.

The power supply unit 4 includes, for example, a base 41 , a matching box 42 , and a power supply 43 .
The base 41 is provided on the bottom of the chamber 2 via an insulating member 41a. The insulating member 41a can cover the side surface of the base 41. The insulating member 41a can be made of a dielectric material such as quartz.

The base 41 is electrically connected to the power source 43 via the matching device 42. An electrostatic chuck 71 can be provided on the base 41. The base 41 serves as an electrode to which high-frequency power is applied from the power source 43, and also serves as a support base for supporting the electrostatic chuck 71. In this case, the base 41 has a flow path therein for flowing cooling water, and can also cool the electrostatic chuck 71. The base 41 can be formed from a metal such as an aluminum alloy, for example.

The matching device 42 is electrically connected between the base 41 and the power source 43. The matching device 42 may include a matching circuit for matching the impedance of the power source 43 side with the impedance of the plasma P side.

The power source 43 can be a radio frequency power source. The power source 43 applies radio frequency power having a suitable frequency for attracting ions (e.g., a frequency between 1 MHz and 27 MHz) to the base 41.

The pressure reducing unit 5 reduces the pressure inside the chamber 2 to a predetermined pressure.
The pressure reducing unit 5 includes, for example, an opening/closing valve 51 , a pump 52 , and a pressure controller 53 .
The on-off valve 51 can be connected to, for example, a hole 2b provided in a side wall of the chamber 2. The on-off valve 51 opens and closes a flow path between the chamber 2 and the pump 52. The on-off valve 51 can be, for example, a poppet valve.

The pump 52 may be, for example, a turbo molecular pump (TMP).

The pressure controller 53 can be provided between the opening/closing valve 51 and the pump 52. The pressure controller 53 controls the internal pressure of the chamber 2 to a predetermined pressure based on the output of a vacuum gauge (not shown) that detects the internal pressure of the chamber 2. The pressure controller 53 can be, for example, an APC (Auto Pressure Controller).

The gas supply unit 6 supplies gas G to the internal space of the chamber 2 through nozzles 2c provided on the side wall of the chamber 2. In this case, multiple nozzles 2c can be provided at approximately equal intervals around the central axis of the chamber 2. In this way, it is possible to suppress variation in the concentration of gas G in the region where plasma P is generated.

The gas supply unit 6 includes, for example, a gas source 61 , a gas controller 62 , and an opening/closing valve 63 .
The gas source 61 supplies the gas G to the inside of the chamber 2 via a gas controller 62 and an opening/closing valve 63. The gas source 61 may be, for example, a high-pressure cylinder that stores the gas G. The gas source 61 may also be, for example, factory piping.

The gas G may be one that generates desired radicals or ions when excited and activated by the plasma P. For example, when the plasma processing is an etching processing, the gas G may be one that generates radicals or ions that can etch the exposed surface of the processing object 100. In this case, the gas G may be, for example, a gas containing chlorine, a gas containing fluorine, or the like. For example, the gas G may be a mixed gas of chlorine gas and oxygen gas, a mixed gas of CHF ₃ , CHF ₃ and CF ₄ , a mixed gas of SF ₆ and helium gas, or the like.

The gas controller 62 can be provided between the gas source 61 and the chamber 2. The gas controller 62 controls at least one of the flow rate and pressure of the gas G supplied from the gas source 61. The gas controller 62 can be, for example, a mass flow controller (MFC).

The on-off valve 63 can be provided between the gas controller 62 and the chamber 2. The on-off valve 63 controls the start and stop of the supply of gas G. The on-off valve 63 can be, for example, a two-port solenoid valve. The function of the on-off valve 63 can also be imparted to the gas controller 62.

The mounting table 7 is provided inside the chamber 2, and the processing object 100 is placed thereon.
The mounting table 7 includes, for example, an electrostatic chuck 71 , a mask ring 72 , a power supply unit 73 , a temperature control unit 74 , and lift pins 75 .

The electrostatic chuck 71 exerts an electrostatic force to adsorb the workpiece 100. The electrostatic chuck 71 may be one that uses Coulomb force or one that uses Johnsen-Rahbek force. The electrostatic chuck 71 can also control the temperature of the workpiece 100 during processing. That is, the electrostatic chuck 71 has at least the function of adsorbing the workpiece 100, and can also have the function of controlling the temperature of the workpiece 100.

The electrostatic chuck 71 can be provided on the base 41. The electrostatic chuck 71 can have, for example, a plate-shaped dielectric and an electrode provided inside the dielectric. The dielectric can be formed, for example, from a ceramic such as aluminum oxide.

A plurality of grooves can be provided on the surface of the dielectric material. A temperature control gas is supplied to the plurality of grooves from a temperature control unit 74. The supplied temperature control gas flows through the inside of a space defined by the grooves and the placed workpiece 100, and heat exchange occurs between the temperature control gas and the workpiece.
The dielectric may have a plurality of holes penetrating the thickness direction. A lift pin 75 may be provided in each of the plurality of holes.

The electrodes are plate-shaped and can be made of a metal such as tungsten or molybdenum. The electrodes can be either unipolar or bipolar. For example, in the case of a bipolar electrode, two electrodes can be arranged side-by-side on the same plane.

The mask ring 72 has a cylindrical shape and can be provided, for example, near the periphery of the upper surface of the base 41 or near the periphery of the upper surface of the electrostatic chuck 71. The mask ring 72 can be made of a dielectric material such as quartz.

The power supply unit 73 has, for example, a DC power supply 73a and a changeover switch 73b. The DC power supply 73a is electrically connected to the electrode of the electrostatic chuck 71. When a voltage is applied to the electrode by the DC power supply 73a, an electric charge is generated on the surface of the electrode facing the workpiece 100. As a result, an electrostatic force is generated between the electrode and the workpiece 100, and the workpiece 100 is attracted to the electrostatic chuck 71 by the generated electrostatic force.

The changeover switch 73b is electrically connected between the DC power supply 73a and the electrode of the electrostatic chuck 71, and switches between adsorption of the workpiece 100 and release of adsorption.

The temperature control unit 74 supplies a temperature control gas to the electrostatic chuck 71 .
The temperature control unit 74 includes, for example, a gas source 74a, a gas controller 74b, a temperature adjustment unit 74c, and an opening/closing valve 74d.

The gas source 74a may be, for example, a high-pressure cylinder containing a temperature-controlled gas. The gas source 74a may also be, for example, factory piping. The temperature-controlled gas may be, for example, helium gas.

The gas controller 74b may be provided between the gas source 74a and the electrostatic chuck 71. The gas controller 74b controls, for example, the flow rate of the temperature control gas supplied from the gas source 74a. The gas controller 74b may be, for example, an MFC.

The temperature adjustment unit 74c can be provided between the gas controller 74b and the electrostatic chuck 71. The temperature adjustment unit 74c adjusts the temperature of the processing object 100 by adjusting the temperature of the temperature control gas. The temperature adjustment unit 74c can be, for example, at least one of a heating device such as a heater and a cooling device equipped with a heat exchanger or the like.

The opening and closing valve 74d can be provided between the temperature adjustment unit 74c and the electrostatic chuck 71. The opening and closing valve 74d controls the start and stop of the supply of the temperature control gas. The opening and closing valve 74d can be, for example, a two-port solenoid valve. The function of the opening and closing valve 74d can also be imparted to the gas controller 74b.

A plurality of lift pins 75 may be provided. When transferring the processed workpiece 100 to a transport device (not shown) or receiving the unprocessed workpiece 100 from a transport device (not shown), the plurality of lift pins 75 are raised to protrude from the upper surface of the electrostatic chuck 71. When processing the workpiece 100, the plurality of lift pins 75 are lowered to move the plurality of lift pins 75 below the upper surface of the electrostatic chuck 71. The lift pins 75 can be raised and lowered by, for example, a control motor such as a servo motor or an air cylinder.

Before describing the detector 8 according to the present embodiment, a detector 180 and a detector 280 according to comparative examples will be described.
FIG. 2 is a schematic cross-sectional view illustrating a detection unit 180 according to a comparative example.
FIG. 2 shows a case where a detection unit 180 and a transmission window 121 are provided instead of the detection unit 8 according to the present embodiment.

As shown in FIG. 2, the detection unit 180 according to the comparative example has a light-projecting unit 180a and a light-receiving unit 180b. In addition, the transmission window 121 is provided on the side wall of the chamber 2 at a position facing the light-projecting unit 180a and at a position facing the light-receiving unit 180b on the side wall of the chamber 2.

The detection light emitted from the light-emitting unit 180a passes through the transmission window 121 and enters the detection position on the surface of the workpiece 100. The detection light is irradiated onto the surface of the workpiece 100 at an angle θa between the surface of the workpiece 100 and the detection light. The detection light that enters the detection position is reflected, passes through the transmission window 121, and enters the light-receiving unit 180b. The light-receiving unit 180b converts the reflected light into an electrical signal that corresponds to the amount of light received. The controller 9 detects the state of the workpiece 100 based on the electrical signal.

Here, assume that the detection light is irradiated vertically to a detection position on the surface of the workpiece 100. The detection light is emitted from the light-projecting unit 180a and spreads before reaching the surface of the workpiece 100. In general, the irradiation area of the detection light at the detection position is determined in advance based on the diameter of the aperture of the light-projecting unit 180a and the spread of the detection light. In this case, if the irradiation area of the detection light at the detection position becomes large, information from the surroundings of the detection position is more likely to be mixed into the detection result. For this reason, it is preferable to make the irradiation area of the detection light at the detection position as small as possible. The spread of the detection light is proportional to the distance L1 shown in FIG. 3.

However, as shown in FIG. 2, when a light projecting unit 180a is provided on the side of the chamber 2 and detection light is irradiated onto the surface of the workpiece 100 from a direction inclined relative to the surface of the workpiece 100, the irradiation area of the detection light at the detection position becomes larger than the predetermined irradiation area described above. For example, in FIG. 2, the irradiation area of the detection light at the detection position expands in the X direction. Therefore, information about the surrounding area of the detection position is mixed into the detection result, making it difficult to detect slight changes at the detection position.

Furthermore, when the distance L between the mounting table 7 on which the workpiece 100 is placed and the window 23 provided above the mounting table 7 becomes longer, the radicals generated by the plasma P generated directly below the window 23 are more likely to be deactivated before reaching the workpiece 100 placed on the mounting table 7. Therefore, the distance L between the mounting table 7 and the window 23 tends to become shorter. When the distance L between the mounting table 7 and the window 23 becomes shorter, the angle θa between the surface of the workpiece 100 and the detection light becomes smaller. The smaller the angle θa, the larger the spread of the irradiation area in the X direction becomes. Therefore, the irradiation area of the detection light at the detection position becomes even larger.

Furthermore, in recent years, the processed parts have become finer, and for example, the opening ratio of the formed irregularities, holes, etc. may be 1% or less. In such cases, the amount of material removed is reduced, so that the change in the detection light becomes even more minute, making it more difficult to detect the optical change at the detection position.
In this way, when the detection unit 180 is provided on the side of the chamber 2, it becomes difficult to detect optical changes at the detection position with good accuracy.

As described above, the sidewall of the chamber 2 is provided with the nozzle 2c for supplying gas G into the chamber 2, the load lock chamber 21, and the like, so the location of the window 23 is limited. In addition, the chamber 2 needs to have an airtight structure, so it is difficult to provide a large window 23. If the location of the window 23 is limited or if a large window 23 is not provided, the arrangement of the light-projecting unit 180a and the light-receiving unit 180b will be limited. If the arrangement of the light-projecting unit 180a and the light-receiving unit 180b is limited, the detection position will be limited, making it difficult to change the detection position.

As explained above, if the detection unit 180 is provided on the side of the chamber 2, it becomes difficult to improve the detection accuracy and change the detection position.

FIG. 3 is a schematic cross-sectional view illustrating a detection unit 280 according to another comparative example.
FIG. 3 shows a case where a detector 280 is provided in place of the detector 8 according to the present embodiment.
As shown in Fig. 3, the detection unit 280 can be a so-called light-emitting/receiving sensor in which a light-emitting unit and a light-receiving unit are integrated. The detection unit 280 is provided outside the chamber 2, on the opposite side of the window 23 from the mounting table 7 side. The detection unit 280 causes detection light to be incident on the detection position from a direction approximately perpendicular to the surface of the workpiece 100, and receives the reflected light reflected at the detection position. In this way, the irradiation area of the detection light at the detection position becomes approximately the same as the above-mentioned predetermined irradiation area. This makes it easy to detect changes at the detection position with high accuracy.

However, as described above, the antenna 31, the Faraday shield, and the like are provided above the window 23. Therefore, the arrangement of the detection unit 280 is limited by the antenna 31, the Faraday shield, and the like.
Therefore, if the detection unit 280 is provided above the window 23, even if the detection accuracy is improved, it becomes difficult to change the detection position.

Next, returning to FIG. 1, the detection unit 8 according to this embodiment will be described.
The detector 8 detects the state of the workpiece 100 based on an optical change that occurs during the plasma processing. For example, the detector 8 can be used to detect the end point of the plasma processing.

As shown in FIG. 1 , the detection unit 8 includes, for example, a light projecting unit 81 and a light receiving unit 82 .
The light-projecting unit 81 may be, for example, a light-emitting diode or a laser diode. The light-projecting unit 81 may irradiate detection light onto the surface of the object 100 to be treated through the window 23. The light-projecting unit 81 may be provided opposite an inclined surface 23a1 to be described later.

The light receiving unit 82 can receive reflected light that is reflected on the surface of the workpiece 100 and exits through the window 23. For example, the light receiving unit 82 can receive interference light that occurs when the detection light is incident on the detection position of the workpiece 100 and convert it into an electrical signal. The light receiving unit 82 can be, for example, a photodiode. Note that the light receiving unit 82 is not limited to a photodiode, and can be anything that can detect optical changes. The light receiving unit 82 can be provided facing the inclined surface 23a2 described below.

The light receiving unit 82 may further include a spectroscope. If a spectroscope is provided, light having a predetermined wavelength can be extracted, thereby improving the detection accuracy.
The controller 9 can detect the state of the workpiece (for example, the end point of the plasma processing) based on the signal from the light receiving unit 82 .

As shown in FIG. 1, a portion of the periphery of the window 23 is provided with an inclined surface 23a1 (corresponding to an example of a first inclined surface) and an inclined surface 23a2 (corresponding to an example of a second inclined surface). If the inclined surfaces 23a1 and 23a2 are uneven, the unevenness will cause light to be scattered, so it is preferable to increase the flatness of the inclined surfaces 23a1 and 23a2. For example, the surface roughness of the inclined surfaces 23a1 and 23a2 can be reduced to Ra 0.02 or less by optical polishing.

FIG. 4 is a schematic cross-sectional view illustrating the light projecting portion 81, the light receiving portion 82, the inclined surface 23a1, and the inclined surface 23a2.
FIG. 5 is a schematic plan view illustrating the light-projecting portion 81, the light-receiving portion 82, the inclined surface 23a1, and the inclined surface 23a2.

As shown in Figures 4 and 5, for example, one end of the inclined surface 23a1 can be connected to the surface of the window 23 opposite the mounting base 7 side. For example, the other end of the inclined surface 23a1 can be connected to a side surface of the window 23. For example, one end of the inclined surface 23a2 can be connected to the surface of the window 23 opposite the mounting base 7 side. For example, the other end of the inclined surface 23a2 can be connected to a side surface of the window 23.

As shown in FIG. 5, in a plan view, the inclined surface 23a2 can be provided at a position facing the inclined surface 23a1 across the central axis 23b of the window 23.
4, the inclined surface 23a1 is inclined with respect to the central axis 23b of the window 23. The inclined surface 23a2 is inclined with respect to the central axis 23b of the window 23. The inclination direction of the inclined surface 23a2 is opposite to the inclination direction of the inclined surface 23a1.

For example, when the window 23 is made of quartz and the internal pressure of the chamber 2 is about 0.1 Pa to 100 Pa, the angle θ1 between the inclined surface 23a1 and the surface of the window 23 opposite the mounting table 7 can be set to "θ1≦43°", as shown in FIG. 4. In this way, it is possible to prevent the detection light emitted from the light projector 81 and introduced into the window 23 via the inclined surface 23a1 from being totally reflected by the surface of the window 23 facing the mounting table 7.

The angle θ2 between the inclined surface 23a2 and the surface of the window 23 opposite the mounting table 7 side can be set to "θ2≦43°". In this way, the reflected light that is reflected at the detection position of the workpiece 100 and enters the surface of the window 23 on the mounting table 7 side can be prevented from being totally reflected on the surface of the window 23 on the mounting table 7 side.

Also, angle θ2 can be the same as angle θ1. However, when angles θ1 and θ2 are the same, differences on the order of manufacturing error can be tolerated. In other words, angle θ2 can be approximately the same as angle θ1.

There are no particular limitations on the planar dimension L2 of inclined surface 23a1 and the planar dimension L3 of inclined surface 23a2 shown in FIG. 5. For example, as shown in FIG. 5, the planar dimension L2 of inclined surface 23a1 can be equal to or greater than the planar dimension L4 of light-projecting portion 81. For example, the planar dimension L3 of inclined surface 23a2 can be equal to or greater than the planar dimension L5 of light-receiving portion 82. In this case, the planar dimension L3 of inclined surface 23a2 may be the same as or different from the planar dimension L2 of inclined surface 23a1.

A gap may be provided between the light-projecting end of the light-projecting unit 81 and the inclined surface 23a1, or, as shown in Figure 4, the light-projecting end of the light-projecting unit 81 and the inclined surface 23a1 may be brought into contact with each other.
However, if a gap is provided between the end of the light-projecting unit 81 on the light-projecting side and the inclined surface 23a1, when vibration is applied to the plasma processing apparatus 1, the light-projecting unit 81 and the inclined surface 23a1 will vibrate separately, which may cause noise. In addition, noise may be generated when external light is incident on the inclined surface 23a1 through the gap. Therefore, it is preferable to bring the end of the light-projecting unit 81 on the light-projecting side into contact with the inclined surface 23a1. Note that a light guide having an optical fiber or the like may be provided between the end of the light-projecting unit 81 on the light-projecting side and the inclined surface 23a1. If a light guide is provided, it becomes easy to arrange the light-projecting unit 81 at any position.

A gap may be provided between the light-receiving end of the light-receiving portion 82 and the inclined surface 23a2, or the light-receiving end of the light-receiving portion 82 may be in contact with the inclined surface 23a2 as shown in FIG. 4.
However, if a gap is provided between the end of the light receiving part 82 on the light receiving side and the inclined surface 23a2, when vibration is applied to the plasma processing apparatus 1, the light receiving part 82 and the inclined surface 23a2 will vibrate separately, which may cause noise. In addition, when external light enters the light receiving part 82 through the gap, noise may be generated. Therefore, it is preferable to bring the end of the light receiving part 82 on the light receiving side into contact with the inclined surface 23a2. Note that a light guide having an optical fiber or the like may be provided between the end of the light receiving part 82 on the light receiving side and the inclined surface 23a2. If a light guide is provided, it becomes easy to arrange the light receiving part 82 at any position.

No antenna 31 or Faraday shield is provided on the periphery of window 23. Therefore, inclined surface 23a1 and inclined surface 23a2 can be provided at any position, making it easier to detect the desired position on the surface of the workpiece 100. As described above, the smaller the angle θa, the larger the irradiation area. By irradiating detection light from inclined surface 23a1 of window 23, the angle θa can be made larger than that of detection unit 180. Therefore, the irradiation area can be made smaller than that of detection unit 180.

In addition, although an example has been given in which one set of inclined surfaces 23a1 and 23a2 is provided, multiple sets of inclined surfaces 23a1 and 23a2 can also be provided. If multiple sets of inclined surfaces 23a1 and 23a2 are provided, the inclined surfaces 23a1 and 23a2 can be selected according to the desired detection position.

Next, the change of the detection position will be described.
If a plurality of pairs of inclined surfaces 23a1 and 23a2 are provided, the detection position can be changed by selecting inclined surface 23a1 and inclined surface 23a2.
The detection position can also be changed when a pair of inclined surfaces 23a1 and 23a2 is provided. In the following, a case where a pair of inclined surfaces 23a1 and 23a2 is provided will be described.

FIG. 6 is a schematic cross-sectional view for illustrating the change of the detection position.
6, by moving light-projecting unit 81 along the inclination direction of inclined surface 23a1, it is possible to change the incident position (detection position) of the detection light on the surface of object 100. If the incident position of the detection light changes, the incident position of the reflected light on inclined surface 23a2 changes, so light-receiving unit 82 is moved according to the incident position of the reflected light on inclined surface 23a2.
In this way, it is possible to easily change the detection position on the surface of the processing object 100. Therefore, it is possible to detect the processing state at a plurality of points on the surface of the processing object 100.

6, the light-projecting unit 81 is moved along the inclination direction of the inclined surface 23a1, but as shown in Fig. 5, the light-projecting unit 81 may be moved in the Y direction along the inclined surface 23a1. Also, the light-projecting unit 81 may be moved in the inclination direction of the inclined surface 23a1 and in the Y direction.
That is, if light projecting portion 81 is provided so as to be movable along inclined surface 23a1 and light receiving portion 82 is provided so as to be movable along inclined surface 23a2, the detection position can be changed.

In addition, when multiple sets of inclined surfaces 23a1 and 23a2 are provided, the selection of the inclined surfaces can be combined with the movement of the light-emitting unit 81 and the light-receiving unit 82 along the inclined surfaces.

The light-projecting unit 81 and the light-receiving unit 82 can be moved, for example, by an operator changing the mounting positions of the light-projecting unit 81 and the light-receiving unit 82 .
As shown in FIG. 1, a moving unit 81a (corresponding to an example of a first moving unit) for moving the light projecting unit 81 and a moving unit 82a (corresponding to an example of a second moving unit) for moving the light receiving unit 82 can be further provided. The moving units 81a and 82a can be, for example, a single-axis table capable of single-axis control or a double-axis table capable of double-axis control. In addition, a combination of multiple single-axis tables or a combination of a single-axis table and a double-axis table can also be used. If the moving units 81a and 82a are provided, it becomes possible to sequentially change the detection position by the controller 9. Therefore, it becomes possible to detect the processing state of multiple points on the surface of the processing object 100 in real time.

As shown in FIG. 1, a cover 83 can be further provided to cover the light-projecting unit 81 and the light-receiving unit 82. The cover 83 is made of metal and can be grounded. When arranging the light-projecting unit 81 and the light-receiving unit 82, a hole may be provided in the cover 34 described above. If a hole is provided in the cover 34, the electromagnetic field generated in the antenna 31 may leak outside the plasma processing device 1. If the cover 83 is provided, the electromagnetic field leaking from the cover 34 can be prevented from leaking outside the plasma processing device 1. The cover 34 may cover the antenna 31, the light-projecting unit 81, the light-receiving unit 82, and the moving units 81a and 82a.

Next, an example of a specific configuration of the moving parts 81a and 82a will be described.
FIG. 7 is a schematic diagram illustrating the moving units 181 and 182. As shown in FIG.
The moving unit 181 is an example of a specific configuration of the moving unit 81 a that moves the light projecting unit 81 .
The moving unit 182 is an example of a specific configuration of the moving unit 82 a that moves the light receiving unit 82 .
7, a light projecting unit 81 can be attached to the moving unit 181. A light receiving unit 82 can be attached to the moving unit 182. The moving unit 181 is provided at a position facing the moving unit 182 with the window 23 therebetween.
The configuration of the moving unit 181 can be similar to the configuration of the moving unit 182. Therefore, hereinafter, the configuration of the moving unit 182 will be mainly described.

FIG. 8 is a schematic diagram of the moving portion 182 in FIG. 7 as viewed from the X direction.
As shown in FIGS. 7 and 8, the moving portion 182 (181) has a guide 182a (181a), a guide 182b (181b), and a case 182c (181c).
The guide 182 a ( 181 a ) is provided on the outer surface of the cover 34 .

FIG. 9 is a schematic diagram illustrating the guide 182a (181a).
FIG. 10 is a schematic diagram illustrating the guide 182b (181b).
FIG. 11 is a schematic diagram of the guide 182b (181b) in FIG. 10 as viewed from the Z direction.

As shown in FIGS. 8 and 9, the guide 182a (181a) has a pair of rails 182a1 (181a1) and a base 182a2 (181a2).
The pair of rails 182a1 (181a1) are provided around a hole 34a provided in the cover 34. The pair of rails 182a1 (181a1) face each other across the hole 34a. For example, the pair of rails 182a1 (181a1) extend along the long sides of the rectangular hole 34a.

The base 182a2 (181a2) is provided on a pair of rails 182a1 (181a1). The base 182a2 (181a2) is provided so as to be movable along the pair of rails 182a1 (181a1). A rectangular hole 182a3 (181a3) is provided on the surface of the base 182a2 (181a2) facing the cover 34. In addition, a holding device (not shown) can be provided to hold the position of the base 182a2 (181a2).

The guide 182a (181a) is not limited to the configuration shown in the example, and may be any guide mechanism capable of linear movement. For example, the guide 182a (181a) may be a guide mechanism having a linear bearing.

As shown in FIGS. 8, 10, and 11, the guide 182b (181b) is provided on a base 182a2 (181a2).
The guide 182b (181b) has a pair of rails 182b1 (181b1) and a base 182b2 (181b2).
The pair of rails 182b1 (181b1) are provided around the hole 182a3 (181a3) provided in the base 182a2 (181a2). The pair of rails 182b1 (181b1) face each other across the hole 182a3 (181a3). For example, the pair of rails 182b1 (181b1) extend along the long sides of the rectangular hole 182a3 (181a3).

The base 182b2 (181b2) is provided on a pair of rails 182b1 (181b1). The base 182b2 (181b2) is provided so as to be movable along the pair of rails 182b1 (181b1). The surface of the base 182b2 (181b2) facing the cover 34 is provided with a hole 182b4 (181b4) into which the case 182c (181c) is inserted. In addition, the opposing side surface of the base 182b2 (181b2) is provided with a screw hole 182b5 (181b5) into which the enamel set (set screw) 182b3 (181b3) is screwed. In addition, a holding device (not shown) for holding the position of the base 182b2 (181b2) can be provided.

The guide 182b (181b) is not limited to the illustrated configuration, and may be any guide mechanism capable of linear movement. For example, the guide 182b (181b) may be a guide mechanism having a linear bearing.

As shown in FIG. 7, a light projecting unit 81 is provided inside the case 181c, and a light receiving unit 82 is provided inside the case 182c.
12A to 12C are schematic diagrams illustrating the case 182c (181c).
As shown in Fig. 12(a), the case 182c (181c) may be a substantially rectangular box. On the opposing short side surfaces of the case 182c (181c), a recessed groove 182c1 (181c1) is provided extending in the longitudinal direction of the case 182c (181c). On one side surface of the case 182c (181c) in the longitudinal direction, the light receiving surface (light projecting surface) of the light receiving unit 82 (light projecting unit 81) is exposed, and wiring is drawn out from the other side surface.

A screw hole (not shown) is provided on the side of the case 182c (181c) where the recessed groove 182c1 (181c1) is not provided. A groove (not shown) is also provided on the side of the light receiving unit 82 (light projecting unit 81). An enamel set (set screw) is screwed into the screw hole provided on the side of the case 182c (181c), and the enamel set (set screw) is inserted into the groove provided on the side of the light receiving unit 82 (light projecting unit 81). The light receiving unit 82 (light projecting unit 81) is fixed to the case 182c (181c) by being pressed by the inserted enamel set.

The method of fixing the light receiving unit 82 (light projecting unit 81) to the case 182c (181c) is not limited to the above. For example, a plurality of recesses are provided on the side of the light receiving unit 82 (light projecting unit 81), and a hole is provided on the side of the case 182c (181c) where the recess 182c1 (181c1) is not provided. Then, a pin may be inserted into one of the plurality of recesses provided in the light receiving unit 82 (light projecting unit 81) through a hole provided on the side of the case 182c (181c), thereby fixing the light receiving unit 82 (light projecting unit 81) to the case 182c (181c). In addition, the outer periphery of the light receiving unit 82 (light projecting unit 81) is male threaded, and the hole penetrating the longitudinal direction of the case 182c (181c) is female threaded. The light receiving unit 82 (light projecting unit 81) may then be fixed to the case 182c (181c) by screwing the light receiving unit 82 (light projecting unit 81) into the case 182c (181c).

12B and 12C, the case 182c (181c) is inserted into the hole 182b4 (181b4) of the base 182b2 (181b2). The enamel set (set screw) 182b3 (181b3) is screwed into the screw hole 182b5 (181b5) of the base 182b2 (181b2). The enamel set (set screw) 182b3 (181b3) protrudes into the hole 182b4 (181b4) and is inserted into the recessed groove 182c1 (181c1) of the case 182c (181c).
Therefore, it is possible to adjust the position of the case 182c (181c) relative to the base 182b2 (181b2), and therefore the position of the light receiving unit 82 (light projecting unit 81) relative to the inclined surface 23a2 of the window 23. In addition, the case 182c (181c) is connected to the cover 34 via the base 182b2 (181b2). Therefore, the light receiving unit 82 (light projecting unit 81) can be connected to the cover 34.
It is also possible to provide a holding device (not shown) for holding the position of the case 182c (181c).

The method of connecting the base 182b2 (181b2) and the case 182c (181c) is not limited to the illustrated configuration. For example, a plurality of recesses may be provided on the side of the case 182c (181c) instead of the groove 182c1 (181c1), and a hole may be provided instead of the screw hole 182b5 (181b5) of the base 182b2 (181b2). Then, the base 182b2 (181b2) and the case 182c (181c) may be connected by inserting a pin into one of the plurality of recesses provided in the case 182c (181c) through the hole provided in the base 182b2 (181b2). The case 182c (181c) may also be clamped and fixed in a vice. In this case, the clamping part of the vice is inserted into the hole in the base 182b2 (181b2) and protrudes into the hole 182b4 (181b4).

When a plurality of light projecting units 81 (light receiving units 82) are provided, a plurality of moving units 181 (182) can be provided.
FIG. 13 is a schematic diagram illustrating a plurality of moving parts.
As shown in FIG. 13, when a plurality of moving parts 181 (182) are provided, a guide 182a (181a) may be used for both.
In this way, the structure of the moving part can be simplified.

14 is a schematic diagram illustrating the configuration of the cover 83, which corresponds to the second cover. As described above, the cover 83 can be provided on the cover 34. The cover 83 is composed of a main body 83b and a door 83a.
The main body 83b is, for example, a metal tube. One end of the main body 83b is connected to the cover 34. Note that, if the hole 34a of the cover 34 can be sealed between the cover 83 and the ceiling of the chamber 2, the surface of the main body 83b that contacts the chamber 2 can be omitted. In other words, the main body 83b may be a metal plate having an n-shaped cross section.
The door 83a is, for example, a metal plate. The door 83a is provided at the other end of the main body 83b in an openable and closable manner. For example, the door 83a is connected to the other end of the main body 83b via a hinge.
14, when the door 83a is in a closed state, the door 83a forms an outer surface of the cover 83. In addition, the door 83a may be provided with a stopper (not shown) for maintaining the door 83a in an open state.

1, the cover 83 covers the light projecting unit 81, the light receiving unit 82, and the moving units 81a, 82a (181, 182). Furthermore, the light projecting unit 81, the light receiving unit 82, and the moving units 81a, 82a (181, 182) may require maintenance or adjustment by an operator.
If the cover 83 is provided with the door 83a, maintenance and adjustment can be easily performed by an operator.

As described above, the cover 83 can prevent the electromagnetic field leaking from the cover 34 from leaking outside the plasma processing device 1. It can also prevent ambient light from entering the light-projecting unit 81 and the light-receiving unit 82.

Next, maintenance of the plasma processing apparatus 1 according to this embodiment will be described.
1, a window 23, a power supply unit 3, and a detection unit 8 are provided on the ceiling side of the chamber 2. These elements require maintenance. For example, the window 23 is damaged over time as a result of plasma processing. This makes it necessary to replace or repair the window 23. Also, there are cases where parts of the power supply unit 3 and the detection unit 8 need to be replaced or adjusted.

However, the window 23, the power supply unit 3, and the detection unit 8 are covered with a cover 34 for blocking the electromagnetic field generated by the antenna 31. Therefore, it is necessary to remove the cover 34 when performing maintenance and to reinstall the cover 34 after maintenance.
As described above, the cover 34 is provided with a moving section to which the light projecting section 81 is attached and a moving section to which the light receiving section 82 is attached. Therefore, when reinstalling the cover 34, it is necessary to place the cover 34 in the original position.

Therefore, the plasma processing apparatus 1 according to the present embodiment is provided with a cover moving unit 10 capable of lifting and lowering the cover 34 .
FIG. 15 is a schematic side view illustrating the cover moving part 10. As shown in FIG.
FIG. 16 is a schematic perspective view illustrating the cover moving part 10. As shown in FIG.
As shown in FIGS. 15 and 16 , the cover moving unit 10 has, for example, a holding unit 11, a driving unit 12, and a plurality of positioning pins 13.

The holding portion 11 holds the cover 34 .
The drive unit 12 raises and lowers the holder 11. When the holder 11 is raised by the drive unit 12, the cover 34 held by the holder 11 moves above the chamber 2. This allows the window 23 and the power supply unit 3 provided on the ceiling side of the chamber 2 to be exposed, facilitating maintenance of the window 23 and the power supply unit 3.
16, the driving unit 12 can also rotate the holding unit 11. For example, the driving unit 12 can rotate the holding unit 11 when raising the holding unit 11 or at the raised end. In this way, the cover 34 can be moved to the side of the chamber 2, making maintenance of the window 23 and the power supply unit 3 even easier.
Furthermore, since the light-projecting unit 81 and the light-receiving unit 82 can be moved together with the cover 34, maintenance is made even easier. The work of removing the light-projecting unit 81 and the light-receiving unit 82 can be omitted. Furthermore, the light-projecting unit 81 and the light-receiving unit 82 are fixed to the cover 34. Therefore, when the cover 34 is returned to its original position for reinstallation, the light-projecting unit 81 and the light-receiving unit 82 also return to their original positions. Therefore, readjustment of the optical axes of the light-projecting unit 81 and the light-receiving unit 82 can also be made easy.

As shown in FIG. 16, multiple positioning pins 13 can be provided on the ceiling of the chamber 2. In addition, holes into which the positioning pins 13 are inserted can be provided in the holding part 11 or the cover 34. When the holding part 11 is lowered by the driving part 12, the positioning pins 13 are inserted into the holes provided in the holding part 11 or the cover 34. Therefore, the cover 34 can be placed back in its original position.

17A and 17B are schematic plan views illustrating a jig 123 used for the maintenance of the window 23.
FIG. 17B is a schematic enlarged view of a portion A of the jig 123 in FIG.
FIG. 18 is a schematic diagram illustrating the installation of the window 23.
17(a) and 18, the jig 123 has a substantially circular ring shape. The jig 123 has a plurality of holes 123b for inserting the positioning pins 13. It is preferable that the positioning pins 13 are arranged asymmetrically with respect to the circular jig 123 so that the jig 123 is always arranged at a predetermined position and in a predetermined orientation every time maintenance is performed. In this way, the positioning pins 13 are arranged so that they will not fit into the holes 123b in any orientation other than the predetermined position and orientation.
17(a) and 17(b), a convex portion 123a is provided on the inner wall of the jig 123. The tip of the convex portion 123a is capable of contacting a flat surface 23a3 provided on the periphery of the window 23. That is, the periphery of the window 23 is provided with the flat surface 23a3 that comes into contact with the convex portion 123a provided on the inner wall of the approximately annular jig 123.

18, when installing the window 23, first, a jig 123 is installed on the ceiling of the chamber 2. At this time, the positioning pin 13 is inserted into the hole 123b, so that the jig 123 is installed at a predetermined position in a predetermined orientation.
Next, the window 23 is inserted into the jig 123, and the flat surface 23a3 of the window 23 is brought into contact with the protrusion 123a of the jig 123. In this manner, the position of the window 23 relative to the chamber 2 can be determined.
Next, after the window 23 is fixed to the chamber 2 , the jig 123 is removed from the chamber 2 .
Using the jig 123 makes it easier to place the window 23 in the desired position.

Although the embodiments have been described above, the present invention is not limited to these descriptions.
With respect to the above-described embodiments, those skilled in the art may add or remove components or modify the design, or add or omit steps or change conditions, as appropriate, and these are also included within the scope of the present invention as long as they incorporate the characteristics of the present invention.
Furthermore, the elements of each of the above-described embodiments can be combined to the greatest extent possible, and combinations of these are also included within the scope of the present invention as long as they include the features of the present invention.

For example, an elastic body may be provided on one side surface in the longitudinal direction of the case 182c (181c). One side surface in the longitudinal direction of the case 182c (181c) is the surface that comes into contact with the window 23. Therefore, it is preferable that the elastic body is made of a material that is less hard than the window 23. The elastic body may be, for example, rubber or sponge. By providing the elastic body, it is possible to prevent the window 23 from being damaged when the cover moving unit 10 returns the cover 34 to its original position. Note that, if the elastic body does not prevent light from passing through the light receiving surface (light projecting surface) of the light receiving unit 82 (light projecting unit 81), the elastic body may also be provided on the light receiving surface (light projecting surface) of the light receiving unit 82 (light projecting unit 81).

For example, the case 182c (181c) may be moved to a position away from the window 23 as shown in FIG. 12(b) before the cover 34 is returned to its original position. In this way, the window 23 can be prevented from being damaged when the cover moving unit 10 returns the cover 34 to its original position. Compared to the case where the elastic body is provided, the optical axes of the light projecting unit 81 and the light receiving unit 82 need to be readjusted. Therefore, the amount of work required by the worker increases. Therefore, the time required for maintenance increases. However, if the base 182b2 (181b2) is held on the pair of rails 182b1 (181b1), the position of the case 182c (181c) in the Y direction is the same as the original position. Therefore, it is easier to readjust the optical axes of the light projecting unit 81 and the light receiving unit 82 than when the light projecting unit 81 and the light receiving unit 82 are separate from the cover 34. Therefore, the amount of work required by the worker decreases. As a result, the time required for maintenance decreases.

1 Plasma processing device, 2 Chamber, 3 Power supply unit, 4 Power supply unit, 5 Pressure reduction unit, 6 Gas supply unit, 7 Placement table, 8 Detection unit, 9 Controller, 10 Cover movement unit, 23 Window, 23a1 Inclined surface, 23a2 Inclined surface, 23a3 Flat surface, 23b Central axis, 31 Antenna, 34 Cover, 81 Light projection unit, 81a Movement unit, 82 Light receiving unit, 82a Movement unit, 100 Processing object, 123 Jig, 123a Convex portion, G Gas

Claims (11)

A chamber capable of maintaining an atmosphere reduced in pressure below atmospheric pressure;
a gas supply unit capable of supplying a gas into the chamber;
a stage provided inside the chamber and capable of supporting an object to be treated;
a pressure reducing unit capable of reducing the pressure inside the chamber;
a window provided in the chamber and facing the stage;
a plasma generating unit that is provided outside the chamber, on a side opposite to the side of the window from the mounting table, and that is capable of generating plasma inside the chamber;
a light projection unit capable of irradiating light onto a surface of the workpiece through the window;
a light receiving unit capable of receiving reflected light that is reflected by a surface of the object to be processed and exits through the window;
Equipped with
The periphery of the window is
a first inclined surface inclined with respect to a central axis of the window;
a second inclined surface inclined relative to a central axis of the window and having an inclination direction opposite to that of the first inclined surface;
is established,
The light projecting unit faces the first inclined surface,
The light receiving unit faces the second inclined surface. 2 . The plasma processing apparatus according to claim 1 , wherein, in a plan view, the second inclined surface faces the first inclined surface across a central axis of the window . 3. The plasma processing apparatus according to claim 1, wherein the following formula is satisfied, where θ1 is an angle between the first inclined surface and a surface of the window opposite to the mounting table side: θ1=θ2/θ3.
θ1≦43° 4. The plasma processing apparatus according to claim 1, wherein the following formula is satisfied, when an angle between the second inclined surface and a surface of the window opposite to the mounting table side is θ2:
θ2≦43° an angle between the first inclined surface and a surface of the window opposite to the mounting table side is θ1;
5. The plasma processing apparatus according to claim 1, wherein when the angle between the second inclined surface and the surface of the window opposite the mounting table side is θ2, the angle θ2 is approximately the same as the angle θ1. the light projecting unit is provided to be movable along the first inclined surface,
6. The plasma processing apparatus according to claim 1, wherein the light receiving section is provided so as to be movable along the second inclined surface. A first moving unit capable of moving the light projecting unit;
A second moving unit capable of moving the light receiving unit;
The plasma processing apparatus according to claim 6, further comprising: a cover that covers an antenna provided in the plasma generating unit and the window;
A cover moving unit capable of raising and lowering the cover;
8. The plasma processing apparatus according to claim 1, further comprising: The plasma generating unit further includes a cover for covering an antenna provided in the plasma generating unit and the window.
The plasma processing apparatus according to claim 7 , wherein the first moving part and the second moving part are attached to the cover. 10. The plasma processing apparatus according to claim 1, wherein the window has a periphery provided with a flat surface that comes into contact with a protrusion provided on an inner wall of a substantially annular jig. a second cover that covers the light projecting unit and the light receiving unit;
11. The plasma processing apparatus according to claim 1, wherein an outer surface of the second cover is openable and closable.

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