JP2004014968A - Plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus capable of measuring plasma luminescence in a processing chamber stably and accurately for a long period without degrading the transmissivity of a measurement port for measuring the plasma luminescence. <P>SOLUTION: For measuring the emission state of a plasma generated in the apparatus, stable plasma measurement can be realized by installing at least one or more branching pipes on a structure contacting to the plasma and a measurement window 140 at the end of the branching pipe and then preventing pollution on the measurement window 140 when measuring the plasma. The plasma processing apparatus has a mechanism heating a component part in the processing chamber in a vacuum state to an arbitrary temperature with an optical heating source 160 arranged in an atmospheric side. Therein the measurement window 140 capable of improving the accuracy of the results of temperature measurement is provided by preventing stray light from the optical heating source 160 or the entry of light caused by the plasma luminescence in the processing chamber and then eliminating the affect of radiation heat from other than these component parts in the processing chamber. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus suitable for forming a fine pattern in a semiconductor manufacturing process, and relates to a measurement port for performing plasma emission in a processing chamber and temperature measurement of components.
[0002]
[Prior art]
In a semiconductor manufacturing process, a plasma processing apparatus is widely used in a fine processing process such as etching, film formation, and ashing. The plasma processing apparatus converts a process gas introduced into a vacuum processing chamber (reactor) into plasma by a plasma generating means, and reacts on the surface of the semiconductor wafer to perform processing such as processing of fine holes and grooves or film formation. At the same time, predetermined processing is performed by exhausting volatile reaction products.
[0003]
In this plasma processing apparatus, the light emission from the plasma being processed is detected, the end point of the etching process is detected, and the film thickness, the etching / film forming speed ( Rate) is measured in real time to improve the accuracy of plasma processing, or by measuring the actual temperature of the processing chamber components and controlling it to the set temperature to minimize errors between samples to be processed. Control is being performed. For example, Japanese Unexamined Patent Publication No. 5-136098 discloses that in a parallel plate type plasma etching apparatus, two or more plasma light receiving sensors are provided on an electrode surface facing a wafer so that the rate of plasma emission at a plurality of points on the wafer can be increased. A method is described in which information on the uniformity and distribution of film thickness and film thickness is obtained to make the plasma density uniform.
[0004]
In Japanese Patent Application Laid-Open No. 3-148118, in a parallel plate type plasma etching apparatus, a laser beam is irradiated on a wafer from above through a top plate electrode, and an etching amount is measured from a reflected laser beam to detect an end point. For the device, by forming a hole of about 10 mm in the portion of the quartz electrode cover through which the laser light passes to prevent contamination of the upper electrode, even if the electrode cover becomes dirty, the laser light does not attenuate accurately. A method of measuring an etching amount and stably detecting an end point is described.
[0005]
In these apparatuses, the measurement window is directly attached to the wall surface of the processing chamber in contact with the plasma, and no description is given of measures to reduce the thickness of the measurement window due to spatter and to prevent spatter and adhesion of reaction products.
[0006]
[Problems to be solved by the invention]
However, the above method has the following problems.
[0007]
First, it is desirable to monitor the state of the thin film on the wafer surface, etc., from above, facing the wafer, or obliquely up to about 45 degrees. However, the plasma processing apparatus that can measure by such a method has a method and a structure. It will be limited. For example, in a microwave ECR or inductively coupled plasma processing apparatus, a transparent window or plate made of quartz may be provided above a wafer in order to radiate a microwave or introduce an induced electric field into a processing chamber. In this case, the state of the wafer surface can be measured from above. However, in a capacitively-coupled so-called parallel plate type plasma processing apparatus, the upper electrode facing the wafer is made of a conductive metal such as aluminum, so that the structure is not such that the wafer surface can be directly seen through. For this reason, a measurement port is provided on the side of the processing chamber to monitor the increase / decrease of the emission spectrum from the plasma, thereby detecting that the processing of the sample by the plasma is completed. However, in practice, reaction products accumulate in the measurement window on which the plasma light receiving sensor is attached as the discharge is repeated, making it difficult for light to pass therethrough. Therefore, it is difficult to perform stable measurement over a long period of time.
[0008]
In order to solve this problem, a method described in Japanese Patent Application Laid-Open No. 3-148118 discloses a method in which a hole of about 10 mm is formed in a measurement portion of a quartz electrode cover directly exposed to plasma through which laser light passes. Thus, even if the deposited film adheres to the surface of the quartz cover, the measurement is not affected. However, in practice, this method also has difficulty in stable measurement. In order to obtain a predetermined plasma density required for plasma processing, high-frequency power of a large power of several kW is applied to the upper electrode. Therefore, a hole having a diameter of about 10 mm as described in the above publication is formed in the electrode or the electrode cover. If formed, the upper electrode and the electrode cover will be damaged due to the occurrence of local abnormal discharge at the hole and the penetration of plasma into the hole. Also, since a bias is applied to the upper electrode, the upper electrode is sputtered with ions in the plasma through the hole in the electrode cover, but since the upper electrode is formed of a metal such as aluminum, There are also problems such as damage or foreign matter generation.
[0009]
Of course, it is possible in principle to measure the wafer surface not from above but facing the wafer but at a shallow angle from the side wall of the processing chamber. However, especially in an oxide film etching apparatus, in order to suppress excessive dissociation of the process gas and to improve the process reproducibility, a flat plate made of silicon or the like is opposed to the sample at a distance of about several tens of mm. In many cases, an opposing flat plate type structure is installed. However, also in this case, the measurement window is directly exposed to the plasma, so that the surface of the measurement window is sputtered and loses transparency, or conversely, if not sputtered, reaction products adhere and deposit. Again, it is difficult to perform stable measurement for a long time due to the loss of transparency of the measurement window.
[0010]
In addition, as mentioned earlier, it is possible to measure the wafer surface from the quartz measurement window above the wafer with a microwave ECR system or an inductively-coupled plasma processing device, etc. The reaction product adheres to the surface of the quartz window to lower the transmittance, and the surface is etched away. Did not.
[0011]
The present invention has been made in order to solve the above-mentioned problems, and a short pipe is installed in a processing chamber in contact with plasma, and a measurement window is installed at the tip of this tankan, so that the sample surface can be mounted regardless of the mounting direction. It is an object of the present invention to provide a plasma processing apparatus capable of accurately and stably measuring the state of plasma and plasma over a long period of time without generating abnormal discharge or foreign matter.
[0012]
[Means for Solving the Problems]
The present inventors have repeatedly studied the above problems from the viewpoints of practicality and reliability, and have found the following solution.
[0013]
The present invention provides a plasma processing apparatus that supplies a processing gas into a vacuum processing chamber, generates plasma by a plasma generator, and performs plasma processing on a sample mounted on a sample stage by the plasma. In order to measure the emission state of the plasma, at least one or more branch pipes are provided in the structure in contact with the plasma, and a measurement window for forming a vacuum is provided at an end of the branch pipe. An observation window is provided at the end of a branch pipe that enables stable and long-term plasma measurement by preventing the contamination of the measurement window during plasma measurement by installing the optical sensor so that the optical sensor end face of the optical transmission body is almost in contact. It is characterized by the following.
[0014]
Also, a mechanism for heating the processing chamber components in a vacuum to an arbitrary temperature by an optical heating source provided on the atmosphere side, and by measuring the radiant heat from the heated processing chamber components and converting them to temperature Provision of means for measuring the temperature of components in the processing chamber to prevent stray light from the optical heating source and light from plasma emission in the processing chamber from entering, and to eliminate the influence of radiant heat from components other than the processing chamber. Thus, a measurement window capable of improving the accuracy of the temperature measurement result is provided.
[0015]
Note that the optical transmitter 141 is not necessarily “transparent”, that is, it is not necessary to have transparency in the entire visible light region, and it is sufficient that the optical transmitter 141 has a sufficient transmittance in the wavelength region to be measured. .
[0016]
Another feature of the present invention is that a short pipe having a diameter capable of securing the amount of light, at least an inner diameter of the sensor used for the optical transmission means, is attached to a wall in contact with the processing chamber, and a measurement window for measurement is attached to a tip of the short pipe. By making the length of the short tube such that the radicals generated in the plasma cannot reach this measurement window, the radicals are prevented from accumulating on the measurement window surface, and the measurement measurement window is contaminated. To prevent a decrease in measurement accuracy due to superposition of noise or the like due to a decrease in transmission amount and a decrease in sensitivity of a measuring device. Furthermore, in order to measure the radiant heat from the structure to be heated by the optical sensor, a measurement window for introducing light from the radiant heat introduction path is provided. In order to prevent such a phenomenon, a light reflecting material is coated on the side of the introduction path, or a light absorbing sleeve is provided.
[0017]
Another feature of the present invention is to increase the diameter of the short pipe halfway to secure the light quantity, attach a short pipe with a small diameter at the tip, and provide a measurement window at the tip of the small short pipe, thereby reducing the amount of light. While using a short tube that has a length that does not allow the radicals to reach the measurement window while ensuring the above.
[0018]
Still another feature of the present invention is to provide a short tube provided with one or more baffle plates in the tube in order to reduce the length of the short tube so that radicals do not reach the measurement window inside the short tube. It has been provided.
[0019]
(Action)
According to the present invention, the measurement window is sputtered or a reaction product is deposited because the short tube having a length such that ions and radicals generated in the plasma do not reach the measurement window is provided, so that the transparency of the measurement window is reduced. By being lost, the accuracy of the measured value is improved, and moreover, stable measurement can be performed for a long period of time. In addition, since the periphery of the optical transmission line is coated with a material that does not transmit radiant heat or covered with a sleeve-like material that does not transmit radiant heat, it is possible to prevent the intrusion of radiant heat other than the object to be measured. Can be improved.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 shows an embodiment in which the present invention is applied to a magnetic field UHF band electromagnetic wave radiation discharge type plasma etching apparatus, and is a schematic sectional view of the plasma etching apparatus.
[0022]
In FIG. 1, a processing chamber 100 is a vacuum container capable of achieving a degree of vacuum of about 10 ⁻⁶ Torr, and an antenna 110 for emitting electromagnetic waves as plasma generating means is provided at an upper part thereof, and a sample W such as a wafer is provided at a lower part thereof. Are provided, respectively. The antenna 110 and the lower electrode 130 are installed so as to face each other in parallel. A magnetic field forming means 101 composed of, for example, an electromagnetic coil and a yoke is provided around the processing chamber 100, and a magnetic field having a predetermined distribution and strength is formed. Then, by the interaction between the electromagnetic wave radiated from the antenna 110 and the magnetic field formed by the magnetic field forming means 101, the processing gas introduced into the processing chamber is turned into plasma to generate plasma P and process the sample W. . The processing chamber 100 is evacuated and pressure-adjusted by a vacuum exhaust system 104 and a pressure control means 105 connected to a vacuum chamber 103, so that the internal pressure can be controlled to a predetermined value of, for example, about 0.5 Pa or more and 4 Pa or less. . The processing chamber 100 and the vacuum chamber 103 are at the ground potential. The temperature of the side wall 102 of the processing chamber 100 is controlled to, for example, about 50 ° C. by a temperature control unit (not shown).
[0023]
An antenna 110 that emits an electromagnetic wave includes a disc-shaped conductor 111, a dielectric 112, and a dielectric ring 113, and is held by a housing 114 as a part of a vacuum container. Further, a plate 115 is provided on the surface of the disc-shaped conductor 111 on the side in contact with the plasma. A processing gas for performing processing such as etching and film formation of the sample is supplied from the gas supply means 116 at a predetermined flow rate and a mixing ratio, is made uniform inside the disc-shaped conductor 111, and is provided on the plate 115. It is supplied to the processing chamber 100 through many holes.
[0024]
A lower electrode 130 is provided below the processing chamber 100 so as to face the antenna 110. The lower electrode 130 holds a sample W such as a wafer on its upper surface, that is, a sample mounting surface, by the electrostatic chuck 131. To the lower electrode 130, a bias power supply 134 for supplying a bias power in a range of 400 kHz to 13.56 MHz is connected via a matching circuit / filter system 135 to control a bias applied to the sample W. In this embodiment, the frequency of the bias power supply 134 is 800 kHz.
Next, a description will be given of a measurement port 140A installed to measure the light emission state of the plasma and a measurement port 140B measuring the radiant heat from the heated structure pair inside the processing chamber, which are the main parts of the present embodiment. I do. In this embodiment, the measurement port 140A is attached to the side of the processing chamber, and 140B is attached to the housing 114.
[0026]
Of course, the attachment of the measurement port is not limited to the two places of the processing chamber side and the housing as described herein, but may be only one place or two or more places, or another place such as arranging on a circumference. It goes without saying that they may be arranged.
[0027]
At the end of the measurement port 140A, optical transmission means 151A and 151B such as an optical fiber and a lens are provided, and optical information reflecting the light emission state of the plasma P is transmitted to the measurement device 152 and measured. . In this embodiment, the optical transmission means 151A and 151B are connected to the common measuring instrument 152. However, there is no problem if separate measuring instruments are provided and connected. The measuring device 152 is controlled by the measuring device control / arithmetic unit 153 and is connected to a higher-order system control unit 154. The system control unit 154 determines via the control interface 155 whether or not the wafer processing has been completed. The measurement port 140B converts the temperature of the component to be heated 161 heated by the optical heating device 160 into radiant heat to measure the temperature of the component to be heated in order to keep the temperature of the component inside the processing chamber constant. Adjust the output of the heating device. Thus, when the heated structure is heated by the plasma and reaches a certain temperature or higher, the output of the optical heating device 160 is adjusted by the heating control device 162 to control the temperature and the output of the heated structure pair 161. By doing so, the life of the optical heating device 160 is extended.
[0028]
Next, the detailed structure of the measurement ports 140A and 140B will be described with reference to FIGS.
[0029]
FIG. 2 is an enlarged cross-sectional view of the measurement port 140A attached to the processing chamber side wall 102 in the embodiment of FIG.
[0030]
A measurement window 143 is attached to an end of the short pipe 142A attached to the processing chamber side wall 102, and an optical transmission means 151 such as an optical fiber or a lens is provided on an end surface of the measurement window 143 on the atmosphere side. Has been. Then, the direct light 145 from the plasma P passes through the short pipe 142A, passes through the measurement window 143, reaches the optical transmission means 151, and is further transmitted to the measuring device 152 for measurement as shown by the optical path indicated by the broken line. Is done.
[0031]
At this time, the ions and radicals generated in the plasma move in vacuum over the distance of the mean free path determined by the pressure and molecular weight, and if the energy level of the colliding wall is high, they strike the colliding ions. The moved ions travel the length of the mean free path. While repeating this process, it reaches the measurement window 143, contacts the atmosphere side, accumulates on the surface of the low-temperature measurement window 143, and reduces the light transmittance of the measurement window 143, thereby detecting the end of the wafer processing. The accuracy of measuring the light emission amount of the generated plasma P decreases, and it is difficult to reliably determine the end of etching. In the present invention, the length of the short tube is set to be equal to or longer than the mean free path length of the gas component generated in the plasma, and the wall surface of the short tube 142A is in contact with the atmosphere separated from the plasma. It is difficult for ions and radicals that have entered from the facing opening to reach the measurement window 143 directly.
[0032]
In addition, ions and radicals that have collided with the low-temperature wall of the short tube 142A absorb their energy, and do not jump out of the wall again.
[0033]
As described above, it becomes difficult for ions and radicals generated in the plasma to reach the measurement window 143, and the measurement window 143 can be kept in a clean state forever, and the light transmittance does not occur. It is possible to maintain the initial measurement accuracy for a long time.
[0034]
Although the principle of FIG. 3 is the same as that of FIG. 2, if the diameter of the short tube is reduced in order to prevent the penetration of ions and radicals into the short tube, the amount of light required for determination does not reach the measurement window 143 and the light transmission If there is a possibility that the sensitivity of the means may be reduced, a short-diameter tube 142B having a larger diameter on the side in contact with the plasma P is provided on the side wall 102, and a sufficient amount of light is secured near the measurement window 143. It is an example. Also in this case, it is desirable that the length of the short pipe be equal to or longer than the mean free path length of the processing gas.
[0035]
In the example of FIG. 4, when there is not enough space around the processing chamber and the length of the short pipe cannot secure the average free path length of the processing gas, ions and radicals 146 that jump into the short pipe 142 </ b> C enter the measurement window 143. This is an example in which a baffle 147 is provided on the inner surface of the short pipe 142C so as not to reach. The ions and radicals that have jumped from the opening surface of the short pipe 142 </ b> C collide with the baffle 147 before reaching the measurement window 143, so that it is difficult to reach the measurement window 143. In this case, the smaller the diameter of the short pipe 142C, the smaller the amount of ions and radicals 146 penetrated, and the smaller the diameter of the short pipe 142C. Therefore, the smaller the diameter of the short pipe 142C, the smaller the diameter of the short pipe 142C. It is important to keep it small. If there is a problem with reducing the diameter, a short tube structure combining FIG. 2 and FIG. 3 can be used.
[0036]
As a comprehensive result of these effects, the measurement window 143 has a long term because the reaction product does not adhere to the end face or the surface does not come off, and the light transmission characteristic is kept constant even after repeated discharge. Stable measurement over a wide range.
[0037]
5 to 7 illustrate the detailed structure of the measurement window when measuring the temperature of the heated structural member 161 in the vacuum processing chamber 100.
[0038]
FIG. 6 shows a state where the present invention is not applied. As the temperature of the heated structural member 161 in the vacuum processing chamber heated by the optical system heating device 160 increases, the radiant heat increases. The radiant heat is measured by the light transmission means 151 through the light transmission body 141 and transmitted as an electric signal to the control interface 155 via the measuring instrument 152.
[0039]
At this time, the light from the optical system heating device 160 and the light emission of the plasma enter the side surface of the photoconductor 141 as stray light 163, and are measured as a heat signal by the light transmission means 151. Therefore, the optical transmission means 151 erroneously detects a temperature higher than the actual temperature of the heated structural member 161 and performs control to lower the output of the optical system heating device 160 in order to maintain the heated structural member 161 at a constant temperature. Do. For this reason, the temperature of the structural material 161 to be heated is maintained at a temperature lower than the set temperature, which is a factor that hinders the performance of the apparatus.
[0040]
FIG. 6 shows an embodiment for solving this problem. In order to prevent the light of the optical system heating device 160 and the stray light 163 of the light emission of the plasma from entering from the side surface of the optical transmission body 141, a reflective material 164 is coated on the side surface of the optical transmission body 141 to prevent the penetration of the stray light 163. This is an example. By preventing the stray light 163 from entering the side surface of the light transmitting body 141, only the radiant heat from the heated structural member 161 alone can be measured in the light transmitting means 151, and the measuring accuracy can be improved.
[0041]
FIG. 7 shows an example in which a sleeve 165 having a wavelength at which the spectrum of the stray light 163 from the light of the optical system heating device 160 or the plasma light is not transmitted is provided on the side surface of the optical transmitter 141 instead of the reflecting member 164. The effects are the same as those described with reference to FIG.
[0042]
By the way, in the above-described embodiments, the optical transmission member 141 is made of transparent quartz. However, this is merely an example. Although the spectrum of the radiant heat is transmitted, the light of the optical system heating device 160 and the stray light of the plasma light are transmitted. If a material that cannot transmit the spectrum of the light 163 can be used for the optical transmitter 141, the stray light 163 of the light of the optical system heating device 160 or the plasma light can be provided without providing the reflector 164 and the sleeve 165 described in FIGS. It is also possible to prevent intrusion.
[0043]
In each of the above-described embodiments, the magnetic field is applied to the UHF band electromagnetic wave radiation discharge type plasma processing apparatus. However, other than the UHF band, the radiated electromagnetic wave is, for example, a microwave of 2.45 GHz, Alternatively, a VHF band from several tens of MHz to about 300 MHz may be used. The magnetic field strength is described as being 160 gauss, which is the electron cyclotron resonance magnetic field strength for 450 MHz. However, it is not always necessary to use a resonance magnetic field, and a stronger magnetic field or a weak magnetic field of about several tens gauss or more is used. May be. Further, it goes without saying that the present invention can be similarly applied not only to the electromagnetic radiation discharge method but also to a capacitively coupled parallel plate plasma processing apparatus, a magnetron type plasma processing apparatus, or an inductively coupled plasma processing apparatus.
[0044]
【The invention's effect】
As described above, according to the present invention, the light emission state of the plasma and the temperature of the structural material to be heated in the processing chamber can be accurately and stably maintained over a long term even at a mass production level by the optical transmission means through the measurement window provided on the atmosphere side. Can measure well. As a result, it becomes possible to detect the end point of the etching process and to control the output of the atmosphere side heating source, so that a more advanced process control method can be provided, and the reproducibility and stability of the process can be improved. It is possible to provide a plasma processing apparatus that can contribute to an improvement in productivity.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a plasma etching apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing a structure of a through-hole branch pipe portion which is a main part of the present invention.
FIG. 3 is a view showing a structure of a through-hole branch pipe part having a large diameter, which is a main part of the present invention.
FIG. 4 is a view showing a structure of a through-hole branch pipe portion provided with a baffle and having a reduced length, which is a main part of the present invention.
FIG. 5 is a diagram showing a configuration example of a conventional measurement window.
FIG. 6 is a diagram showing an embodiment of a measurement window according to the present invention.
FIG. 7 is a view showing another embodiment of the measurement window in the present invention.
[Explanation of symbols]
100 processing chamber, 101 magnetic field forming means, 102 side wall of processing chamber, 103 vacuum chamber, 104 evacuation system, 105 pressure control means, 110 antenna
111: disk-shaped conductor, 112: dielectric, 113: dielectric ring,
114 ... housing, 115 ... plate, 116 ... gas supply means,
130: lower electrode, 131: electrostatic chucking device, 134: bias power supply,
135: Matching circuit / filter system, 140A / B: Measurement port,
141: optical transmission body, 142A / B / C: short tube, 143: measurement window,
145: plasma direct light, 146: ion / radical, 147 ... baffle,
151A / B: optical transmission means, 152: measuring instrument, 153: measuring instrument control / calculation means, 154: system control means, 154: control interface,
160: optical heating device, 161: heated structural material, 162: heating control device
163: stray light, 164: reflective material, 165: sleeve, P: plasma, W: sample

Claims (7)

In a plasma processing apparatus that supplies a processing gas into a vacuum processing chamber, generates plasma by a plasma generator, and performs plasma processing on a sample placed on a sample stage by the plasma,
In order to measure the light emission state of the plasma generated in the apparatus, at least one or more branch pipes are provided in a structure in contact with the plasma, and a measurement window for forming a vacuum is provided at an end of the branch pipe. An optical sensor of an optical transmitter is installed on the atmosphere side of the window so that the end face is almost in contact with the window, and contamination of the measurement window during plasma measurement is prevented. A plasma processing apparatus characterized in that an observation window is provided at an end. 2. The plasma processing apparatus according to claim 1, wherein a mechanism for heating a component in the processing chamber in a vacuum to an arbitrary temperature by an optical heating source provided on the atmosphere side, and radiant heat from the component in the processing chamber heated. A means for measuring the temperature of the processing chamber components by measuring and converting the temperature to prevent stray light from the optical heating source and light from plasma emission in the processing chamber from entering; A plasma processing apparatus having a measurement window capable of improving the accuracy of a temperature measurement result by eliminating the influence of radiant heat. 2. The plasma processing apparatus according to claim 1, wherein the length of the branch pipe is equal to or longer than the mean free path length of the processing gas. 2. The plasma processing apparatus according to claim 1, wherein the diameter of the short pipe on the side where the measurement window is mounted is made smaller than the diameter of the short pipe on the side mounted in the vacuum processing chamber, thereby attenuating the amount of light incident on the optical sensor. A plasma processing apparatus characterized in that a branch pipe with a clean measurement window is attached without any trouble. 2. The plasma processing apparatus according to claim 1, wherein a baffle plate is installed on an inner surface of the short tube attached to the vacuum processing chamber, and a branch tube is attached, the length of the short tube being shorter than the average free path length of the processing gas. Characteristic plasma processing equipment. In the plasma processing apparatus according to claim 2, the periphery of the light introduction path to the measurement window is coated with a material that does not transmit the wavelength from the optical heating source or the plasma, and captures only the radiant heat from the measured object, A plasma processing apparatus for preventing light from entering from an object other than an object to be measured. The plasma processing apparatus according to claim 2, wherein a sleeve made of a material that does not transmit a wavelength from an optical heating source or plasma is provided around a light introduction path to the measurement window, so that the object to be measured can be removed. A plasma processing apparatus, which takes in only radiant heat of an object and prevents light from entering from an object other than an object to be measured.

Images