JP2006194679A - Temperature/thickness measuring device, temperature/thickness measuring method, temperature/thickness measuring system, controlling system, and controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring device capable of measuring temperature or thickness of a plurality of objects to be measured at once, without forming hole, through which measuring light pass to each object to be measured to avoid the trouble of having to install a device. <P>SOLUTION: The temperature/thickness measuring device is equipped with an illuminant 110 irradiating light of wavelength possible of transmitting through and reflected from each object to be measured T<SB>1</SB>to T<SB>n</SB>, a splitter 120 splitting the light from the illuminant into measuring light and reference light, a reference light reflecting means 140 (for example, reference mirror) reflecting the reference light from the splitter, an optical length modulating means (for example, a driving means driving the reference mirror) 142 modulating optical length of the reference light reflected from the reference light reflecting means, and an optical receiver 150 measuring interference of light between the reference light reflected from the reference light reflecting means for irradiation with the reference light from the splitter toward the reference light reflecting means and each measuring light reflected from each object to be measured for irradiation with measuring light from the splitter toward a plurality of objects to be measured so as to transmit through each object to be measured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a temperature / thickness measuring apparatus, a temperature / thickness measuring method, a temperature / thickness measuring device capable of accurately measuring the temperature or thickness of a measurement object such as a front surface, back surface, and inner layer of a semiconductor wafer or a liquid crystal substrate. The present invention relates to a measurement system, a control system, and a control method.

  For example, accurate measurement of the temperature of a substrate to be processed, for example, a semiconductor wafer (hereinafter also simply referred to as “wafer”) processed by a substrate processing apparatus is performed on the wafer according to the results of various processes such as film formation and etching. This is extremely important from the viewpoint of accurately controlling the shape and physical properties of the film and holes to be formed. For this reason, the temperature of a wafer has been conventionally measured by various methods such as a resistance thermometer and a measurement method using a fluorescence thermometer for measuring the temperature of the back surface of a substrate.

  In recent years, a temperature measurement method and apparatus capable of directly measuring the wafer temperature, which has been difficult with the conventional temperature measurement method as described above, have been studied (see, for example, Patent Document 1). A specific example of such a temperature measuring device will be described with reference to FIGS. FIG. 19 is a diagram for explaining the principle of a conventional temperature measuring device, and FIG. 20 is a diagram conceptually showing an interference waveform measured by the temperature measuring device.

  The temperature measuring apparatus 10 shown in FIG. 19 uses a low coherence interferometer based on, for example, a Michelson interferometer. The temperature measurement device 10 includes a light source 12 configured by, for example, a low-coherence SLD (Super Luminescent Diode), reference light that irradiates the reference mirror 20 with light from the light source 12, and measurement light that irradiates the measurement object 30. The beam splitter 14 is divided into two, a reference mirror 20 which is provided so as to be driven in one direction and can change the optical path length of the reference light, the reflected light of the reference light from the reference mirror 20 and the measurement object 30. And a light receiver 16 that receives the reflected light of the measurement light and measures interference.

  In such a temperature measuring apparatus 10, the light from the light source 12 is divided into two parts, the reference light and the measuring light, by the beam splitter 14, and the measuring light is irradiated toward the measurement object and reflected by each layer, The reference light is irradiated toward the reference mirror 20 and reflected by the mirror surface. Then, the respective reflected lights again enter the beam splitter 14, and at this time, depending on the optical path length of the reference light, they are overlapped to cause interference, and the interference wave is detected by the light receiver 16.

Therefore, when the temperature is measured, the reference mirror 20 is driven in one direction to change the optical path length of the irradiation light. Then, since the coherence length of the light from the light source 12 is short due to the low coherence property of the light source 12, normally, strong interference occurs in a place where the optical path length of the measurement light and the optical path length of the reference light coincide with each other, and in other places Interference is substantially reduced. In this way, the reference mirror 20 is driven in the front-rear direction (arrow direction in FIG. 19), for example, and the optical path length of the reference light is changed to thereby change the refractive index difference in each layer (A layer, B layer) of the measurement object ( The reflected light of the measurement light and the reflected light of the reference light by n ₁ , n ₂ ) interfere with each other, and an interference waveform as shown in FIG. 20 is detected. As a result, it is possible to measure the temperature of the measurement object in the depth direction.

  For example, in FIG. 20, when the measurement object is heated by a heater or the like and the temperature changes, the measurement object expands. At this time, since the refractive index of each layer of the measurement object 30 also changes, the position of the interference waveform shifts before and after the temperature change, the width between the peak positions changes, and the peak position of the interference waveform changes. The width corresponds to the above temperature change. Further, since the peak position of the interference waveform corresponds to the moving distance of the reference mirror 20, the temperature change is measured by accurately measuring the width of the peak position of the interference waveform based on the moving distance of the reference mirror 20. be able to.

International Publication No. 03/087744 Pamphlet

  By the way, the temperature measuring apparatus as described above can measure not only the temperature of the wafer but also the temperature of the electrode plate of the upper electrode provided in the processing chamber of the substrate processing apparatus. In this case, it is convenient if the temperature of the wafer and the temperature of the electrode plate can be measured at once. That is, it is possible to easily measure the temperatures of a plurality of temperature objects while minimizing costs, and to reduce the labor and time required for temperature measurement as much as possible.

  However, the following problems can be considered when measuring the temperature of a plurality of measurement objects arranged opposite to each other, such as an electrode plate of a wafer and an upper electrode. For example, when measuring light from a light source is transmitted through an optical fiber, the optical fiber for measuring the temperature of the wafer is routed from below the processing chamber, and the optical fiber for measuring the electrode plate of the upper electrode is from above the processing chamber. It is conceivable to manage them. However, if this is done, the measurement light from the same light source will be routed from the top and bottom of the processing chamber, so it is difficult to route such an optical fiber, and it takes time to install the temperature measurement device. There is a problem.

  In this regard, it is considered that both the optical fiber for measuring the temperature of the wafer and the optical fiber for measuring the temperature of the electrode plate of the upper electrode may be routed from above the processing chamber. However, in this case, since the wafer is positioned so as to be spaced apart below the electrode plate of the upper electrode, in order to irradiate the measurement light on the wafer, the electrode of the upper electrode that is the measurement object is used. There is a problem that a hole for passing an optical fiber for irradiating measurement light to a wafer which is another measurement object must be formed in the plate. This requires an extra hole in the object to be measured and also takes time to form the hole.

  Therefore, the present invention has been made in view of such a problem, and an object of the present invention is to measure the temperature / thickness when measuring the temperature or thickness of a plurality of measurement objects arranged opposite to each other. It is possible to reduce the time and effort of mounting the measuring device, and it is possible to reduce the temperature or thickness of a plurality of measuring objects without forming a hole through which measuring light for measuring other measuring objects passes. An object of the present invention is to provide a temperature / thickness measuring device or the like that can measure the thickness at once.

  In order to solve the above problems, according to an aspect of the present invention, there is provided a temperature / thickness measuring apparatus that measures the temperature or thickness of a plurality of objects to be measured that are opposed to each other based on light interference. A light source that emits light having a wavelength that passes through and reflects each measurement object, a splitter that splits the light from the light source into measurement light and reference light, and the reference light from the splitter is reflected. Reference light reflecting means, optical path length changing means for changing the optical path length of the reference light reflected from the reference light reflecting means, and reference light from the splitter is irradiated toward the reference light reflecting means Reference light transmission means for transmitting to the reference light irradiation position, and measurement light for transmitting the measurement light from the splitter to the measurement light irradiation positions for irradiating the measurement objects toward the plurality of measurement objects. Biography Temperature / thickness characterized by comprising: means; and light receiving means for measuring light interference between each measurement light reflected from each measurement object and reference light reflected from the reference light reflection means A measuring device is provided.

  In order to solve the above-described problem, according to another aspect of the present invention, there is provided a temperature / thickness measurement method for measuring the temperature or thickness of a plurality of measurement objects arranged opposite to each other based on light interference. And irradiating the measurement objects split from a light source that irradiates light having a wavelength that transmits and reflects the measurement objects toward the plurality of measurement objects so as to pass through the measurement objects. Irradiating the reference light toward the reference light reflecting means, and changing each optical path length of the reference light reflected from the reference light reflecting means by scanning the reference light reflecting means in one direction. Measuring the interference of light between each measurement light reflected from the object and the reference light reflected from the reference light reflecting means; and the temperature or thickness of each measurement object based on the result of the interference measurement. Measuring step Temperature / thickness measurement wherein the door is provided.

  According to the above-described apparatus or method of the present invention, when the measurement light split from the light source is irradiated toward a plurality of measurement objects arranged opposite to each other, the measurement light is first (maximum). The reflected light is reflected by the front and back surfaces of the measurement object arranged at the end and transmitted through the first measurement object, so that the transmitted light can be used as measurement light for the second measurement object arranged. Similarly, since the measurement light passes through each measurement object, the light that has been transmitted through the measurement object that has been placed before that of the measurement object that has been placed in the third or later position is the same as that of the measurement object. It becomes measurement light and is reflected by the front and back surfaces of each measurement object. Therefore, the temperature or thickness of each measurement object can be determined at one time by measuring the interference of each measurement light reflected from each measurement object and the reference light reflected from the reference light reflecting means.

  In this way, by using the measurement light transmitted through a certain measurement object as the measurement light for the next measurement object, the measurement light split from the light source is emitted toward a plurality of measurement objects. Each measurement light reflected from each measurement object can be received with a simple configuration. Thereby, for example, an optical fiber that transmits measurement light can be easily routed, and it is possible to eliminate the need for forming a hole in the measurement object. In addition, since the temperature of a plurality of measurement objects can be measured at one time with one temperature measurement device, the temperature measurement time can be shortened as much as possible while suppressing an increase in cost as much as possible.

  In addition, in the above apparatus or method, by providing a bypass optical path connected in parallel with the measurement light optical path in the middle of the measurement light optical path, the measurement light transmitted without passing through the measurement light bypass optical path is referred to. It is possible to measure the light interference with the light and the light interference between the measurement light and the reference light transmitted at least once via the detour optical path of the measurement light. There is a shift in the interference of these lights, and the shift amount of the interference of these lights can be adjusted by adjusting the optical path length of the detour optical path of the measurement light.

  Therefore, by adjusting the optical path length of the bypass optical path of the measurement light, for example, the interference waveform between the measurement light and the reference light for each measurement object can be measured in the vicinity. For this reason, it is sufficient to move the reference light reflecting means (for example, the reference mirror) at least within a range in which the interference waveform between the measurement light and the reference light for each measurement object can be measured. Thereby, since the moving distance of the reference light reflecting means (for example, the reference mirror) can be shortened, the time required for temperature or thickness measurement can also be shortened. In this case, if the optical path length of the detour optical path of the measurement light is adjusted so that all or part of the peak widths of the interference waveforms for each measurement object overlap, the reference light reflecting means (for example, reference Since the movement distance of the mirror) can be shortened, the time required for temperature or thickness measurement can be further shortened.

  Further, in the above apparatus or method, a measurement light splitter for splitting the measurement light from the splitter into a plurality of measurement lights is further provided, and each measurement light from the measurement light splitter is supplied to the plurality of measurement objects. By irradiating the measurement objects toward each other, a plurality of measurement lights from the measurement light splitter are reflected from the measurement light reflected from the measurement objects and the reference light reflecting means. Light interference with reference light can be measured. Thereby, since the optical axis of each measurement light can be adjusted for each measurement object, the optical axis of the measurement light can be easily adjusted regardless of the accuracy of the parallelism of each measurement object.

  Further, in the above apparatus or method, the reference light reflecting means is provided with a plurality of reflecting surfaces, and the reference light from the splitter is reflected by the reflecting surfaces to reflect a plurality of reference lights having different optical path lengths. Thus, it is possible to measure light interference between the plurality of reference lights reflected from the respective reflecting surfaces and the respective measuring lights reflected from the respective measuring objects. The light interference is shifted, and the shift amount of the light interference can be adjusted by adjusting the positions of the plurality of reflecting surfaces of the reference light reflecting means.

  Therefore, by adjusting the positions of the plurality of reflecting surfaces of the reference light reflecting means, for example, the interference waveform between the measurement light and the reference light for each measurement object can be measured in the vicinity, or each measurement object In other words, all or part of the peak widths of the interference waveforms for the above are overlapped and measured. For this reason, it is sufficient to move the reference light reflecting means (for example, the reference mirror) at least within a range in which the interference waveform between the measurement light and the reference light for each measurement object can be measured. Thereby, since the moving distance of the reference light reflecting means (for example, the reference mirror) can be shortened, the time required for temperature or thickness measurement can also be shortened.

  In the above apparatus or method, a reference light splitter is further provided for splitting the reference light from the splitter into a plurality of reference lights, and the plurality of reference lights from the reference light splitter are supplied to the reference light reflecting means. By irradiating, it is possible to measure the interference of light between each reference light reflected from the reference light reflecting means by a plurality of reference lights from the reference light splitter and each measurement light reflected from each measurement object. There is a shift in the interference of these lights, and the shift amount of the interference of these lights can be adjusted by adjusting the optical path lengths of the plurality of reference lights from the reference light splitter.

  Therefore, by adjusting the optical path lengths of a plurality of reference lights from the reference light splitter, for example, the interference waveform between the measurement light and the reference light for each measurement object can be measured in the vicinity, For example, all or part of the peak width of the interference waveform of the object may be measured in an overlapping manner. For this reason, it is sufficient to move the reference light reflecting means (for example, the reference mirror) at least within a range in which the interference waveform between the measurement light and the reference light for each measurement object can be measured. Thereby, since the moving distance of the reference light reflecting means (for example, the reference mirror) can be shortened, the time required for temperature or thickness measurement can also be shortened.

  Further, in the above apparatus or method, by providing a bypass optical path connected in parallel with the reference light optical path in the middle of the reference light optical path, the reference light transmitted without passing through the reference light bypass optical path is measured. It is possible to measure the light interference with the light and the light interference between the reference light and the measurement light transmitted at least once via the detour optical path of the reference light. There is a shift in the interference of these lights, and the shift amount of the interference of these lights can be adjusted by adjusting the optical path length of the detour optical path of the reference light.

  Therefore, by adjusting the optical path length of the bypass optical path of the reference light, for example, the interference waveform between the measurement light and the reference light for each measurement object can be measured in the vicinity. For this reason, it is sufficient to move the reference light reflecting means (for example, the reference mirror) at least within a range in which the interference waveform between the measurement light and the reference light for each measurement object can be measured. Thereby, since the moving distance of the reference light reflecting means (for example, the reference mirror) can be shortened, the time required for temperature or thickness measurement can also be shortened. In this case, if the optical path length of the detour optical path of the reference light is adjusted so that all or part of the peak widths of the interference waveforms for each measurement object overlap, the reference light reflecting means (for example, reference Since the movement distance of the mirror) can be shortened, the time required for temperature or thickness measurement can be further shortened.

  In the above apparatus or method, each light (light from a light source, measurement light, reference light, etc.) may be transmitted via the air. According to this, light can be transmitted without using an optical fiber or a collimating fiber. Thereby, even light having a wavelength that does not pass through the optical fiber or collimate fiber (for example, a wavelength of 2.5 μm or more) can be used as a light source.

  In the above apparatus or method, each measurement object is formed of, for example, silicon or a silicon oxide film, and the light source is configured to be capable of irradiating light having a wavelength of, for example, 1.0 to 2.5 μm. The Since such light having a wavelength of 1.0 to 2.5 μm is transmitted through and reflected by silicon or a silicon oxide film, the measurement light transmitted through a certain measurement object is measured on the next measurement object. It can be used as light.

  In the above apparatus or method, the object to be measured is, for example, a substrate to be processed (for example, a semiconductor wafer or a glass substrate) to be processed in a substrate processing apparatus (for example, a plasma processing apparatus) or the periphery of the substrate to be processed. A peripheral ring (for example, a focus ring) to be disposed and an electrode plate (for example, an electrode plate for an upper electrode, an electrode plate for a lower electrode, etc.) disposed to face the substrate to be processed. As described above, according to the present invention, it is possible to measure the temperature or thickness of the electrode plate and the substrate to be processed or the peripheral ring, which are arranged to face each other in the substrate processing apparatus, with the simple configuration as described above. Therefore, it is possible to reduce the labor and time required for temperature measurement as much as possible while minimizing the cost.

  In the above method, the light intensity of the light source may be changed during measurement of light interference between the measurement light and the reference light. For example, the light intensity of the light source may be gradually increased according to the moving distance of the reference light reflecting means, or the light intensity of the light source may be changed for each measurement object. When changing the light intensity of the light source for each measurement object, for example, the light intensity of the light source is changed according to the reflection intensity of the measurement light from each measurement object, or the measurement object farther from the irradiation position of the measurement light is the light source. The light intensity may be increased. This prevents a decrease in the light intensity of the measurement light due to the measurement light passing through the inside of each measurement object and the space between the measurement objects during measurement of the interference of the measurement light and the reference light. As a result, it is possible to prevent a decrease in the light intensity (S / N ratio) with respect to noise of the interference waveform between the measurement light and the reference light and prevent the interference waveform from being broken. Thereby, for example, the detection accuracy of the peak position of the interference waveform can be improved, and the measurement accuracy of temperature and thickness based on the peak-to-peak width of the interference waveform can be improved.

  In order to solve the above problems, according to another aspect of the present invention, a high frequency power is applied to an electrode plate disposed in a processing chamber, whereby a predetermined substrate is disposed on the substrate to be disposed facing the electrode plate. A temperature / thickness measurement system comprising: a substrate processing apparatus that performs the above processing; a temperature / thickness measuring apparatus attached to the substrate processing apparatus; and a control device that controls the temperature / thickness measuring apparatus, A temperature / thickness measuring device is a light source that emits light having a wavelength that transmits and reflects each measurement object including at least the electrode plate and the substrate to be processed or a peripheral ring disposed around the substrate to be processed. A splitter for splitting light from the light source into measurement light and reference light, reference light reflecting means for reflecting the reference light from the splitter, reference light reflecting from the reference light reflecting means light Optical path length changing means for changing the length, reference light transmitting means for transmitting the reference light from the splitter to the reference light irradiating position for irradiating the reference light to the reference light reflecting means, and measurement light from the splitter Measurement light transmitting means for transmitting to each measurement object to be irradiated so as to pass through each measurement object, measurement light transmission means for transmitting to each measurement object, each measurement light reflected from each measurement object, and said reference light reflection means A light receiving means for measuring light interference with the reference light reflected from the light receiving means, and the control device obtains the temperature or thickness of each measurement object based on the result of the interference measurement from the light receiving means. A temperature / thickness measurement system is provided.

  According to such a temperature / thickness measurement system according to the present invention, a substrate processing apparatus such as an optical fiber that transmits measurement light can be easily routed, and the formation of a hole in a measurement object can be eliminated. It is possible to reduce the trouble of mounting the temperature measuring device on the head. In addition, the temperature of a plurality of measurement objects including a substrate to be processed and an electrode plate disposed opposite to the substrate processing apparatus, for example, can be measured at one time with a single temperature measuring apparatus, so that an increase in cost is minimized. However, the temperature measurement time can be shortened as much as possible.

  In order to solve the above problems, according to another aspect of the present invention, a high frequency power is applied to an electrode plate disposed in a processing chamber, whereby a predetermined substrate is disposed on the substrate to be disposed facing the electrode plate. A control system comprising: a substrate processing apparatus that performs the above processing; a temperature / thickness measuring apparatus installed in the substrate processing apparatus; and a controller that controls the temperature / thickness measuring apparatus and the substrate processing apparatus. The temperature / thickness measuring apparatus irradiates light having a wavelength that transmits and reflects at least each measurement object including at least the electrode plate and the substrate to be processed or a peripheral ring disposed around the substrate to be processed. A light source, a splitter for splitting light from the light source into measurement light and reference light, reference light reflecting means for reflecting reference light from the splitter, reference light reflected from the reference light reflecting means Optical path length changing means for changing the optical path length of the light, reference light transmitting means for transmitting the reference light from the splitter to the reference light reflecting position for irradiating the reference light reflecting means, and measurement from the splitter Measuring light transmitting means for transmitting light to the measuring object to be transmitted so as to transmit the measuring object to the measuring object, measuring light reflected from the measuring object, and the reference The light receiving means for measuring the interference of the light with the reference light reflected from the light reflecting means, and the control device determines the temperature or thickness of each measurement object based on the result of the interference measurement from the light receiving means. A control system characterized in that, based on these temperatures or thicknesses, at least one of temperature control and process control of the substrate to be processed in a processing chamber of the substrate processing apparatus is controlled. It is subjected.

  According to such a control system according to the present invention, for example, the temperature or thickness of a plurality of measurement objects including a substrate to be processed and an electrode plate disposed to face a substrate processing apparatus can be measured at a time, Since temperature control and process control of the substrate to be processed can be performed based on these temperatures or thicknesses, process characteristics of the substrate to be processed can be accurately controlled, and stability of the substrate processing apparatus can be improved. Can do.

In order to solve the above problems, according to another aspect of the present invention, a high frequency power is applied to an electrode plate disposed in a processing chamber, whereby a predetermined substrate is disposed on the substrate to be disposed facing the electrode plate. A control method for a control system of a substrate processing apparatus that performs the above-described processing is a method for transmitting a plurality of measurement objects including at least the electrode plate and the substrate to be processed or a peripheral ring disposed around the substrate to be processed. Irradiating measurement light split from a light source that emits light having a reflected wavelength toward the plurality of measurement objects so as to pass through the measurement objects, and directing the reference light toward the reference light reflecting means An irradiation process;
While changing the optical path length of the reference light reflected from the reference light reflecting means by scanning the reference light reflecting means in one direction, the measuring light reflected from each measurement object and the reference light reflecting means Measuring the interference of light with the reflected reference light; measuring the temperature or thickness of each measurement object based on the result of the interference measurement; and measuring the temperature or thickness of each measurement object Based on the above, there is provided a control method comprising a step of performing at least one of temperature control and process control of the substrate to be processed in the substrate processing apparatus.

  According to such a control method according to the present invention, for example, the temperature or thickness of a plurality of measurement objects including an electrode plate and a substrate to be processed that are opposed to each other in a processing chamber of a substrate processing apparatus can be measured at a time. Since the temperature control and process control of the substrate to be processed can be performed based on these temperatures or thicknesses, the process characteristics of the substrate to be processed can be accurately controlled, and the stability of the substrate processing apparatus can be improved. Can be improved.

  According to the present invention, when measuring the temperature or thickness of a plurality of measurement objects arranged opposite to each other, the measurement light transmitted through a certain measurement object is used as the measurement light of the next measurement object. By using it, it is possible to receive each measurement light reflected from each measurement object with a simple configuration of irradiating the measurement light split from the light source toward a plurality of measurement objects. As a result, it is possible to reduce the time and effort of installing the temperature / thickness measuring device, and it is possible to perform multiple measurement without forming a hole for passing measurement light for measuring other measurement objects. The temperature or thickness of the object can be measured at once.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(Temperature measuring device according to the first embodiment)
A temperature measuring apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a temperature measuring apparatus according to the first embodiment of the present invention. The temperature measuring apparatus 100 according to the present embodiment is based on the principle as shown in FIG. 19 described above, and has a simple configuration, for example, a plurality of measuring objects T ₁ arranged to face each other as shown in FIG. the through T _n once the scanning of the reference beam reflecting means (e.g., a reference mirror) is obtained to be able to be temperature measured. A specific configuration of such a temperature measuring apparatus 100 is as follows.

  As shown in FIG. 1, the temperature measuring device 100 includes a light source 110, a splitter 120 for splitting light from the light source 110 into measurement light and reference light, and reference light from the splitter 120. The reference light reflecting means 140 for reflecting the light and the optical path length changing means for changing the optical path length of the reference light reflected from the reference light reflecting means 140 are provided. The optical path length changing means is constituted by a driving means 142 such as a motor for driving the reference light reflecting means 140 constituted by a reference mirror or the like in one direction parallel to the incident direction of the reference light. Thus, by driving the reference mirror in one direction, the optical path length of the reference light reflected from the reference mirror can be changed.

In addition, the temperature measuring device 100 reflects the measurement objects T _{1 to} T _n when the measurement light from the splitter 120 is irradiated onto the plurality of measurement objects T _{1 to} T _n arranged opposite to each other. A light receiving means 150 for measuring interference between the first to nth measurement lights and the reference light reflected from the reference light reflecting means 140 when the reference light reflecting means 140 is irradiated with the reference light from the splitter 120; Prepare.

The light source 110 that constitutes such a temperature measuring device 100 is a light that passes through and reflects each of the measurement objects T _{1 to} T _n , and the interference between the measurement light split from the light source 110 and the reference light is measured. Use light that can be emitted. This is because in the present invention, the temperature of the measurement light from the light source 110 is measured based on the interference between the reference light and the light that passes through and reflects the measurement objects T _{1 to} T _n . Specifically, the measurement light from the light source 110 is used for the measurement object T ₁ arranged first (at the extreme end), and the measurement objects T _{2 to} T _n arranged after the second are used. The light that has passed through the measurement light is used as measurement light for the measurement object placed before that, and the measurement light receives the light reflected from the measurement objects T _{1 to} T _n . Thus, without forming a hole for passing a measurement light for measuring other measurement object in the measurement object, it is possible to measure the temperature of all of the measurement target T ₁ through T _n.

  For example, when measuring the temperature of a wafer as an object to be measured, the light source 110 is such that the reflected light from at least the distance between the front surface and the back surface of the wafer (usually about 800 to 1500 μm) does not cause interference. Light is preferred. Specifically, for example, it is preferable to use low coherence light. Low coherence light refers to light with a short coherence length. The center wavelength of the low coherence light is preferably 0.3 to 20 μm, for example, and more preferably 0.5 to 5 μm. The coherence length is preferably 0.1 to 100 μm, for example, and more preferably 3 μm or less. By using such low-coherence light as the light source 110, it is possible to avoid an obstacle due to unnecessary interference, and it is possible to easily measure interference with reference light based on reflected light from the surface or inner layer of the wafer.

Further, in order to measure the temperature of components in the processing chamber such as the electrode plate of the upper electrode in addition to the wafer as the measurement object, it is preferable to use light having a wavelength capable of transmitting these as the light source 110. When the plurality of measurement objects T _{1 to} T _n are made of a silicon material such as silicon or silicon oxide (for example, quartz) such as a wafer or an electrode plate of an upper electrode, the silicon material can be transmitted 1 It is preferable to use a light source 110 that can emit low-coherence light having a wavelength of 0.0 to 2.5 μm.

  Examples of the light source using the low-coherence light include SLD (Super Luminescent Diode), LED, high-intensity lamp (tungsten lamp, xenon lamp, etc.), ultra-wideband wavelength light source, and the like. Among these low-coherence light sources, it is preferable to use an SLD as the light source 110 in view of high brightness.

  As the splitter 120, for example, an optical fiber coupler is used. However, the present invention is not limited to this, and any material that can be split into reference light and measurement light may be used. As the splitter 120, for example, an optical waveguide type demultiplexer, a half mirror, or the like may be used.

  The reference light reflecting means 140 is constituted by a reference mirror, for example. As the reference mirror, for example, a corner cube prism, a plane mirror, or the like is applicable. Among these, it is preferable to use a corner cube prism in view of parallelism with incident light of reflected light. However, as long as the reference light can be reflected, the present invention is not limited to the above, and may be constituted by, for example, a delay line (similar to an optical path changing means such as a piezo tube delay line described later).

  The driving means 142 for driving the reference light reflecting means 140 is preferably constituted by, for example, a stepping motor that is driven in a direction parallel to the incident direction of the reference light (arrow direction in FIG. 1). If the stepping motor is used, the moving distance of the reference light reflecting means 140 can be easily detected by the motor driving pulse. However, the optical path length changing means is not limited to the motor as long as the optical path length of the light reflected from the reference light reflecting means can be changed. For example, a voice coil motor type delay line using a voice coil motor is used. In addition, the optical path length changing means may be constituted by a piezo tube type delay line, a linear motion stage type delay line, a laminated piezo type delay line, or the like.

  The light receiving means 150 is preferably configured using, for example, a photodiode in consideration of low cost and compactness. Specifically, for example, a PD (Photo Detector) using a Si photodiode, an InGaAs photodiode, a Ge photodiode, or the like is used. However, the invention is not limited to the above as long as the interference between the measurement light from the measurement object T and the reference light from the reference light reflecting means 140 can be measured. For example, the light receiving means 150 using an avalanche photodiode, a photomultiplier tube, or the like. May be configured.

The reference light from the splitter 120 is transmitted to a reference light irradiating position for irradiating the reference light reflecting means 140 via a reference light transmitting means (for example, an optical fiber F _Z with a collimator having a collimator attached to the tip of the optical fiber c). It has become so. Further, the measurement light from the splitter 120 irradiates the measurement objects T _{1 to} T _n via measurement light transmission means (for example, a collimator-equipped optical fiber F in which a collimator is attached to the tip of the optical fiber b). It is transmitted to the irradiation position. The reference light transmission means or the measurement light transmission means is not limited to the collimator-equipped optical fiber, and may be a collimated fiber.

With respect to the measurement light irradiation position by the measurement light transmission means, all measurement objects T _{1 to} T _n from the measurement object T ₁ (or T _n ) where the measurement light from the splitter 120 is arranged on the outermost side. a position to be irradiated so as to transmit the measured object T ₁ through T _n towards. As a result, the measurement light split from the light source 110 transmits and reflects the measurement objects T _{1 to} T _n , so that not only the first measurement light reflected on the front and back surfaces of the measurement object T ₁ but also the measurement object. can be obtained second measurement light reflected by the surface and the back surface of the measurement target T ₂ is transmitted through the object T _1, it can be obtained for the third to n measuring beam in the same manner. That is, when the measurement object T _k (1 ≦ k ≦ n) among the measurement objects T _{1 to} T _n is considered, the measurement light from the light source 110 is arranged on the side irradiated with the measurement light. By passing through the measurement objects T _{1 to} T _k-1 and irradiating the measurement object T _k , it is possible to obtain the k-th measurement light by reflecting on the front and back surfaces of the measurement object T _k .

In this way, by using the measurement light transmitted through a certain measurement object as the measurement light of the other measurement object, the first measurement light to the nth measurement light for all the measurement objects T _{1 to} T _n are used. Since light can be received through the optical fiber F with a collimator, the temperatures of the measurement objects T _{1 to} T _n can be measured at a time.

On the other hand, FIG. 2 shows a temperature measuring apparatus 102 configured using light that does not pass through the measurement objects T _{1 to} T _n as the light source 110 of measurement light as a comparative example. In the temperature measuring apparatus 102 shown in FIG. 2, the measurement light from the splitter 120 is further split into first to nth measurement lights using an optical add / drop multiplexer (OADM) 132, and the first to nth measurement lights are split. 1 to the n-th measurement light via the optical fiber _g 1 to g _n tip collimator with optical fibers _F 1 to F _n fitted with collimator respectively, at a point to be irradiated to the measurement object _T 1 through T _n It is different from what is shown in.

In such a temperature measuring device 102, because the not transmitted through the measurement target T ₁ through T _n light using a light source 110 of the measuring light, holes through which the measurement light for measuring other measurement object in the measurement object There is a problem that must be formed. Moreover, the larger the number n of measurement objects, the more holes must be formed in the measurement object correspondingly. This requires an extra hole in the object to be measured and also takes time to form the hole.

It is necessary to form a hole for the passage of the second to n-th measurement light for measuring another measurement object T ₂ through T _n respectively to specifically, for example measurement target T _1, further measurement Holes for passing the third to n-th measurement lights for measuring other measurement objects T _{3 to} T _n must be formed in the object T ₂ .

  Further, in the temperature measuring apparatus 102, the reference light reflecting means 140 is scanned (moved) by the number n of the measurement objects for each measurement object while switching the first to nth measurement lights by the optical communication multiplexer 132, and each measurement object. The temperature must be measured for each item. In this case, there is a problem that it takes time and labor to measure the temperature.

In this respect, in the temperature measuring apparatus 100 shown in FIG. 1, since the light transmitted through the measurement object can be used as the measurement light, it is split from the light source 110 without forming holes in the measurement objects T _{1 to} T _n. The irradiated measurement light is only irradiated so as to pass through each measurement object from the measurement object (T ₁ or T _n ) arranged at the extreme end toward the plurality of measurement objects T _{1 to} T _n . Thus, the first measurement light to the n-th measurement light reflected by the measurement objects T _{1 to} T _n can be received. Thereby, it is possible to detect the interference wave of the light of each of the first to n-th measurement light and the reference light at a time only by scanning the reference light reflecting means 140 such as a reference mirror once. For this reason, the time required for temperature measurement can be shortened as much as possible.

As described above, according to the temperature measuring apparatus 100 according to the present embodiment, the measurement light split from the light source 110 is irradiated toward the plurality of measurement objects T _{1 to} T _n . , The temperature of each of the measurement objects T _{1 to} T _n can be detected at a time. As a result, it is possible to reduce the trouble of mounting the temperature measuring device, such as easy handling of the optical fiber and making it unnecessary to form a hole in the measurement object. In addition, since the temperature of a plurality of measurement objects can be measured at one time with one temperature measurement device, the temperature measurement time can be shortened as much as possible while suppressing an increase in cost as much as possible.

  The intensity ratio between the measurement light split by the splitter 120 and the reference light is, for example, 1: 1. As a result, the intensity of the measurement light and the reference light become substantially the same, so that an interference waveform that makes it easy to measure the width between peaks, for example, can be obtained. The intensity of each light is not limited to this.

Further, shutter means (not shown) capable of turning on and off the transmission of the measurement light may be provided between the measurement objects T _{1 to} T _n . For example, the reference light reflecting means (for example, a reference mirror) 140 is set so that the measuring object T ₁ and the measuring object T ₂ are blocked by the shutter means so that the measuring light is not irradiated to the measuring objects T _{2 to} T _n. By driving, only the interference wave of the first measurement light and the reference light can be obtained. Further, for example, a reference light reflecting means (for example, a reference mirror) is configured so that the measurement light is not irradiated to the measurement objects T _{3 to} T _n by blocking between the measurement object T ₂ and the measurement object T ₃ by a shutter means, for example. If 140 is driven, only interference waves of the first measurement light, the second measurement light, and the reference light can be obtained. In this case, the interference wave of the first measuring beam and the reference beam, it is possible to identify the above-described method of blocking between the measurement target T ₁ and the measurement object T ₂ by the shutter means, the reference beam and the second measuring beam Only the interference wave can be identified. By providing the shutter unit, the measuring light reflected by the object T ₁ through T _n can be identified.

(Operation of temperature measuring device)
In the temperature measuring apparatus 100 having such a configuration, as shown in FIG. 1, the light from the light source 110 is incident on one of the input terminals (input ports) of the splitter 120 via the optical fiber a, for example. Is divided into two output terminals (output ports). Among these, the light from one output terminal (output port) is used as measurement light, and the measurement objects T _{1 to} T _n are transmitted through measurement light transmission means, for example, an optical fiber F with a collimator having a collimator attached to the tip of the optical fiber b. And is reflected by the front surface, boundary surface, and back surface of each layer of each of the measuring objects T _{1 to} T _n .

On the other hand, the light from the other output terminal of the splitter 120 is 2 minutes wave (output port) as the reference light, emitted from the reference light transmitting means such as an optical fiber c distal to the collimator optical fiber with F _Z, fitted with a collimator , And reflected by a reference light reflecting means (for example, a reference mirror) 140. Then, the first to n-th measurement lights reflected by the measurement objects T _{1 to} T _n are incident on the splitter 120 via the optical fiber F with a collimator and reflected by a reference light reflecting means (for example, a reference mirror) 140. reference light even through the optical fiber F _Z with collimator enters the splitter 120, the reference light is combined again with these first to n measuring light, such as Si photodiode, InGaAs photodiodes, Ge photodiode etc. Is incident on the light receiving means 150 constituted by a PD using, for example, via an optical fiber d, and the light receiving means 150 detects an interference waveform between the first to n-th measurement light and the reference light.

(Specific example of interference waveform between measurement light and reference light)
Here, a specific example of the light interference between the measurement light and the reference light obtained by the temperature measurement apparatus 100 is shown in FIG. FIG. 3 shows an interference waveform between the first and second measurement lights reflected by the measurement objects T ₁ and T ₂ and the reference light reflected by the reference light reflecting means 140. 3A shows the interference waveform before the temperature change, and FIG. 3B shows the interference waveform after the temperature change. In FIG. 3, the vertical axis represents the interference intensity, and the vertical axis represents the moving distance of the reference mirror.

As the light source 110, using the low coherence light source capable of transmitting a measurement object T _1. According to the low-coherence light source, since the coherence length of the light from the light source 110 is short, usually strong interference occurs in a place where the optical path length of the measurement light and the optical path length of the reference light coincide with each other, and interference occurs in other places. It has the characteristic of being substantially reduced. For this reason, the reference light reflecting means (for example, the reference mirror) 140 is driven before and after the reference light irradiation direction, for example, and the optical path length of the reference light is changed to thereby change the front and back surfaces of the measuring objects T ₁ and T _2. In addition, if there are further layers inside the measurement objects T ₁ and T ₂ , the measurement light reflected by these refractive index differences and the reference light interfere with each other. As a result, it is possible to measure the temperature of the depth direction of the measurement target T ₁ and T _2.

According to FIGS. 3A and 3B, when the reference light reflecting means (for example, the reference mirror) 140 is scanned in one direction, an interference wave between the surface of the measuring object T1 and the reference light _first appears. , then the interference wave between the rear surface and the reference light of the measurement target T ₁ is appears. With reference light reflecting means 140 further continue to scan, interference between the reference light and the measurement target T ₂ of the surface appears, then the interference wave of the reference light appears and the rear surface of the measurement target T _2. In this way, it is possible to detect the interference waves on the front and back surfaces of the measurement objects T ₁ and T ₂ at a time only by scanning the reference light reflecting means 140 once.

(Temperature measurement method based on interference wave)
Next, a method for measuring temperature based on the interference of light between measurement light and reference light will be described. As a temperature measurement method based on the interference wave of the measurement light and the reference light, for example, there is a temperature conversion method using an optical path length change based on a temperature change. Here, a temperature conversion method using the positional deviation of the interference waveform will be described.

When the measurement objects T ₁ and T ₂ are heated by a heater or the like, the measurement objects T ₁ and T ₂ are expanded and their refractive indexes change, so that the position of the interference waveform is before and after the temperature change. As a result, the peak-to-peak width of the interference waveform changes. At this time, if there is a temperature change in each measurement target T _1, T _2, position offset of each measurement target T _1, T ₂ each interference waveform, peak-to-peak width of the interference waveform changes. A temperature change can be detected by measuring the peak-to-peak width of the interference waveform for each of the measurement objects T ₁ and T ₂ . For example, in the case of the temperature measuring apparatus 100 as shown in FIG. 1, the peak-to-peak width of the interference waveform corresponds to the moving distance of the reference light reflecting means (for example, the reference mirror) 140. By measuring the moving distance of the reference mirror, the temperature change can be detected.

Hereinafter, the temperature measurement method will be described more specifically with the thicknesses of the measurement objects T ₁ and T ₂ measured in FIG. 3 being d ₁ and d ₂ and the refractive indexes being n ₁ and n ₂ , respectively. When the measurement objects T ₁ and T ₂ are irradiated with measurement light and the reference mirror is scanned in one direction, interference between the first measurement light reflected on the front surface and the back surface of the measurement object T ₁ and the reference light and surface light transmitted is in the measurement target T ₂ measured object T _1, the interference of the second measurement light and the reference light reflected by the back surface, the measurement target T _1, as shown in FIG. 3 _(a), T _For every two, two interference waveforms are obtained.

At this time, when the measurement target T _1, T ₂ for example to heat from a heater, the temperature of the measurement target T _1, T ₂ is increased, the measurement object by change in temperature T _1, T ₂ is expanded refracted The rate also changes. As a result, as shown in FIG. 3B, the peak positions of the remaining one interference waveform are shifted with respect to each of the measurement objects T ₁ and T ₂ with reference to one interference waveform among the two interference waveforms. As a result, the peak-to-peak width of the interference waveform changes. For example, in FIG. 3 (b), the reference to the interference waveform of the surface at each measurement target T _1, T _2, the position of the back surface of the interference waveform, respectively t ₁ compared to the case 3 of _(a), t It is shifted by ₂ . Thereby, the peak-to-peak widths of the interference waveforms at the measurement points P ₁ and P ₂ change from W ₁ and W ₂ shown in FIG. 3A to W ₁ ′ and W ₂ ′ shown in FIG. .

  Such a shift in the peak position of the interference waveform generally depends on the linear expansion coefficient α specific to each layer of the measurement object with respect to the thickness d, and mainly changes in the refractive index specific to each layer with respect to changes in the refractive index n. Depends on temperature coefficient β. It is known that the temperature coefficient β of the refractive index change also depends on the wavelength.

Therefore, when the thicknesses d ₁ ′ and d ₂ ′ of the wafers after the temperature change at the respective measurement objects T ₁ and T ₂ are expressed by mathematical expressions, the following mathematical expressions (1-1) and (1-2) are obtained. . In the following mathematical formulas (1-1) and (1-2), ΔT ₁ and ΔT ₂ indicate changes in temperature of the measurement objects T ₁ and T ₂ . alpha _1, shows the temperature coefficient of the alpha ₂ respectively show a linear expansion coefficient of the measuring object _{T 1, T 2, β 1} , β 2 is the refractive index change of the measurement target _T 1, _{T 2,} respectively . Further, d ₁ and n ₁ indicate the thickness and refractive index of the measurement target T ₁ before the temperature change, respectively, and d ₂ and n ₂ indicate the thickness and refraction of the measurement target T ₂ before the temperature change, respectively. Shows the rate.

d ₁ ′ = d ₁ · (1 + α ₁ ΔT ₁ ), n ₁ ′ = n ₁ · (1 + β ₁ ΔT ₁ ) (1-1)

d ₂ '= d ₂ · (1 + α ₂ ΔT ₂ ), n ₂ ' = n ₂ · (1 + β ₂ ΔT ₂ ) (1-2)

As shown in the above mathematical formulas (1-1) and (1-2), the optical path lengths of the first and second measurement lights that are transmitted through and reflected by the measurement objects T ₁ and T ₂ change due to temperature changes. The optical path length is generally expressed as a product of the thickness d and the refractive index n. Therefore, the optical path lengths of the first and second measurement lights that pass through and reflect the measurement objects T ₁ and T ₂ before the temperature change are L ₁ and L ₂ , respectively, and the temperatures at the measurement objects T ₁ and T ₂ are respectively Assuming that the optical path lengths after changing by ΔT ₁ and ΔT ₂ are L ₁ ′ and L ₂ ′, L ₁ and L ₁ ′ are respectively expressed by the following formula (1-3), and L ₂ and L ₂ 'Is represented by the following mathematical formula (1-4).

L ₁ = d ₁ · n ₁ , L ₁ ′ = d ₁ ′ · n ₁ ′ (1-3)

L ₂ = d ₂ · n ₂ , L ₂ ′ = d ₂ ′ · n ₂ ′ (1-4)

Therefore, the difference (L ₁ ′ −L ₁ , L ₂ ′ −L ₂ ) before and after the temperature change of the optical path lengths of the first and second measurement lights in the measurement objects T ₁ and T ₂ is expressed by the above formula (1− When calculated and arranged according to 1), (1-2), (1-3), and (1-4), the following equations (1-5) and (1-6) are obtained, respectively. In addition, in the following mathematical formulas (1-5) and (1-6), α · β << α and α · β << β are taken into consideration and the minute terms are omitted. In the initial state before heat is applied to the wafer, the wafer thickness d and refractive index n can be assumed to be the same for all measurement points P ₁ and P ₂ in the same wafer plane. L = d · n = L ₁ = L ₂ can be set.

L ₁ '-L ₁ = d ₁ ' · n ₁ '-d ₁ · n ₁ = d ₁ · n ₁ · (α ₁ + β ₁ ) · ΔT ₁
= L ₁ · (α ₁ + β ₁ ) · ΔT ₁ (1-5)

L ₂ '-L ₂ = d ₂ ' · n ₂ '-d ₂ · n ₂ = d ₂ · n ₂ (α ₂ + β ₂ ) · ΔT ₂
= L ₂ · (α ₂ + β ₂ ) · ΔT ₂ (1-6)

Here, the optical path length of the measurement light in each measurement object corresponds to the peak-to-peak width of the interference waveform with the reference light. For example, the optical path lengths L ₁ and L ₂ of the first and second measurement lights of the measurement objects T ₁ and T ₂ before the temperature change are respectively the peak-to-peak widths W ₁ and W ₂ of the interference waveform shown in FIG. ₂ and the optical path lengths L ₁ ′ and L ₂ ′ of the first and second measurement lights of the measurement objects T ₁ and T ₂ after the temperature change are the peaks of the interference waveform shown in FIG. This corresponds to the inter-space widths W ₁ ′ and W ₂ ′. Therefore, the peak-to-peak width of the interference waveform with the reference light in each measurement object can be measured by the moving distance of the reference light reflecting means (for example, the reference mirror) 140 according to the temperature measuring apparatus 100 as shown in FIG.

Therefore, the linear expansion coefficient alpha ₁ of the measurement target _T 1, _{T 2,} the temperature coefficient beta ₁ of alpha ₂ and refractive index change, if examined beta ₂ in advance, the reference in the measurement target _T 1, _{T 2} By measuring the peak-to-peak width of the interference waveform with light, the temperature can be converted to the temperature of each of the measurement objects T ₁ and T ₂ using the above formulas (1-5) and (1-6).

  Thus, when converting the interference wave to the temperature, the optical path length expressed between the peaks of the interference waveform varies depending on the linear expansion coefficient α and the temperature coefficient β of the refractive index change as described above. It is necessary to investigate in advance α and the temperature coefficient β of the refractive index change. In general, the linear expansion coefficient α and the temperature coefficient β of refractive index change of a substance including a wafer that can be a measurement object may depend on the temperature depending on the temperature range. For example, the coefficient of linear expansion α generally does not change so much in the temperature range of about 0 to 100 ° C., so it can be regarded as constant. However, in the temperature range of 100 ° C. or higher, the temperature increases depending on the material. Since the rate of change may be large, the temperature dependency cannot be ignored in such a case. Similarly, the temperature dependence β of the refractive index change may not be negligible depending on the temperature range.

For example, in the case of silicon (Si) constituting a wafer, it is known that the linear expansion coefficient α and the temperature coefficient β of refractive index change can be approximated by, for example, a quadratic curve in a temperature range of 0 to 500 ° C. For details, see JAMcCaulley, VMDonnelly et al. (JAMcCaulley, VMDonnelly, M. Vernon, and I. Taha,
"Temperature dependence of the near-infrared refractive index of
silicon, gallium arsenide, and indium phosphide "Phy. Rev. B49, 7408, 1994).

  Thus, since the linear expansion coefficient α and the temperature coefficient β of the refractive index change depend on the temperature, for example, the linear expansion coefficient α and the temperature coefficient β of the refractive index change corresponding to the temperature are examined in advance through experiments, etc. If it is stored in advance in a memory (for example, a memory 440 of the control device 400 described later) as the reference data for use, and the temperature is converted using the reference data for temperature conversion, it can be converted into a more accurate temperature.

Note that the method for measuring the temperature based on the interference wave between the measurement light and the reference light is not limited to the above method, and the relationship between the optical path length and the temperature for each of the measurement objects T _{1 to} T _n is tested. And stored in advance in a memory (for example, a memory 440 of the control device 400 described later) as temperature conversion reference data, and each of the measurement objects T _{1 to} T is used by using the temperature conversion reference data. _The optical path length (the peak width of the interference wave) measured based on the interference wave between the measurement light and the reference light for _n may be directly converted into temperature. According to this, even if the linear expansion coefficient α and the temperature coefficient β of the refractive index change are not known, the measurement result of the interference wave between the measurement light and the reference light can be easily converted into temperature.

For the measurement target object T in particular in example, the optical path length at a known temperature t _i and L _i, the optical path length at a given temperature t and L _t, a temperature coefficient of linear expansion α and the refractive index change β Then, in a temperature range in which the temperature dependence of the linear expansion coefficient α and the temperature coefficient β of the refractive index change can be ignored, a certain temperature t can be expressed by the following equation (2-1). The following equation (2-1) is the same as the case where L1 ′ = L _t , L1 = L _i , ΔT1 = t−t _i , α ₁ = α, β ₁ = β in the above equation (1-5). . When the following (2-1) is arranged, a certain temperature t can be expressed by the following equation (2-2). In the following equation (2-2), when the temperature dependence of the linear expansion coefficient α and the temperature coefficient β of the refractive index change can be ignored, α + β is considered to be constant, so the constant coefficients are replaced with A ₁ and B ₁ . And a linear expression as shown in the following expression (2-3).

L _t −L _i = L _i · (α + β) · (t−t _i ) (2-1)

t = (1 / (α + β)) · (L _t / L _i ) − (1 / (α + β) + t _i ) (2-2)

t = A ₁ · (L _t / L _i ) + B ₁ (2-3)

When the temperature dependence of the linear expansion coefficient α and the temperature coefficient β of the refractive index change cannot be ignored, it may be expressed by a quadratic expression as shown in the following expression (2-4). The coefficients in this case are A ₂ , B ₂ and C ₂ .

t = A ₂ · (L _t / L _i ) ² + B ₂ · (L _t / L _i ) + C ₂ (2-4)

The coefficients A ₁ , B _{1 in} the above equation (2-3) and the coefficients A ₂ , B ₂ , C ₂ in the above equation (2-4) are actually measured at several temperatures by experiments. Ask for. For example, if an experimental result as shown in FIG. 4 is obtained with respect to the relationship between the temperature and the optical path length, the known temperature t _{i is set} to 40 ° C., and the optical path length at that time is set to L _i = L _40. −4) The coefficients in the equation are A ₂ = −1.2496 × 10 ⁵ , B ₂ = −2.6302 × 10 ⁵ , and C ₂ = −1.3802 × 10 ⁵ , respectively.

The equation (2-4) thus obtained by experiment is stored in advance in a memory (for example, a memory 440 of the control device 400 to be described later) as temperature conversion reference data, and based on the interference wave between the measurement light and the reference light. from the measured optical path length _{L t} seek _L t _{/ L 40} Te, by fitting the _L t / _{L i} of (2-4) below, it is possible to convert the optical path length _{L t} of the temperature t.

  Note that the temperature measurement method based on the interference wave between the measurement light and the reference light is not limited to the method described above. For example, a method using an absorption intensity change based on a temperature change may be used. A method in which an optical path length change based on the above and an absorption intensity change based on a temperature change are combined may be used.

(Temperature measurement system according to the second embodiment)
Next, a temperature measurement system for a substrate processing apparatus according to a second embodiment will be described with reference to the drawings. The temperature measurement system of the substrate processing apparatus according to the second embodiment is a specific example when the temperature measurement apparatus according to the first embodiment is applied to the substrate processing apparatus. FIG. 5 is a diagram showing a schematic configuration of a temperature measurement system according to the second embodiment. In this case, for example, the present invention is applied to the temperature measurement of two temperature objects T ₁ (for example, the electrode plate Tu of the upper electrode) and T ₂ (for example, the wafer Tw) that are arranged to face each other in a substrate processing apparatus such as a plasma etching apparatus. Will be described as an example.

  The temperature measurement system shown in FIG. 5 is roughly composed of a temperature measurement device 200, a substrate processing device 300, and a control device 400. A temperature measuring apparatus 200 shown in FIG. 5 includes a light source 110 shown in FIG. 1 as a low-coherence light source, for example, an SLD 210 that emits light having low coherence, and a splitter that splits the light from the light source 110 into measurement light and reference light. 120 includes, for example, a 2 × 2 optical fiber coupler 220, and the light receiving unit 150 includes, for example, a PD 250 using a Ge photodiode, the reference light reflecting unit 140 includes, for example, a reference mirror 240, and the driving unit 142 includes For example, the stepping motor 242 that drives the reference mirror 240 is used.

  As the light source 110 such as the SLD 210 that is the source of the measurement light, a light source that can irradiate light that can pass through at least the electrode plate Tu of the upper electrode 350 is used. As a result, the measurement light passes through the electrode plate Tu of the upper electrode 350 and is also applied to the wafer Tw, so that the transmitted light can be used as measurement light for measuring the temperature of the wafer Tw. The electrode plate Tu of the upper electrode 350 is formed of a silicon material such as silicon or a silicon oxide film (for example, quartz). In such a case, a wavelength of 1.0 to 2.5 μm that can transmit the silicon material is used. It is preferable to use a light source 110 that can emit light.

  As shown in FIG. 5, the substrate processing apparatus 300 includes a processing chamber 310 that performs a predetermined process such as an etching process or a film forming process on the wafer Tw, for example. An upper electrode 350 and a lower electrode 340 facing the upper electrode 350 are disposed inside the processing chamber 310. The lower electrode 340 also serves as a mounting table for mounting the wafer Tw. The wafer Tw is loaded into the processing chamber 310 from a gate valve (not shown) provided on the side surface of the processing chamber 310, for example. The lower electrode 340 and the upper electrode 350 are connected to high-frequency power sources 320 and 330 for applying predetermined high-frequency power, respectively.

The upper electrode 350 is configured to support the electrode plate Tu as a measurement object T ₂ is located in its lowermost with the electrode support 351. The electrode plate Tu is made of, for example, a silicon material (silicon, silicon oxide, etc.), and the electrode support 351 is made of, for example, an aluminum material.

  An introduction pipe (not shown) through which a predetermined processing gas is introduced is provided above the upper electrode 350. A large number of discharge holes (not shown) are formed in the electrode plate Tu so that the processing gas introduced from the introduction pipe is uniformly discharged toward the wafer Tw placed on the lower electrode 340.

  The upper electrode 350 is provided with cooling means. This cooling means controls the temperature of the upper electrode 350 by, for example, forming a coolant channel formed in the electrode support 351 of the upper electrode 350 and circulating the coolant through the coolant channel. The refrigerant channel is formed in a substantially annular shape, and is divided into two systems, for example, an outer refrigerant channel 352 for cooling the outside of the upper electrode 350 and an inner refrigerant channel 354 for cooling the inner side. Formed. The outer refrigerant flow path 352 and the inner refrigerant flow path 354 are supplied from the supply pipe as indicated by the arrows shown in FIG. 5, flow through the respective refrigerant flow paths 352 and 354, and are discharged from the discharge pipe. It is configured to return to an external refrigerator (not shown) and circulate. The same refrigerant may be circulated in these two refrigerant flow paths, or different refrigerants may be circulated. Note that the cooling means for the upper electrode 350 is not limited to the one having the two refrigerant flow paths shown in FIG. 5, and may be one having only one refrigerant flow path. You may provide the refrigerant | coolant flow path which branches.

  The electrode support 351 is provided with a low heat transfer layer 356 between an outer portion where the outer refrigerant channel 352 is provided and an inner portion where the inner refrigerant channel 354 is provided. Accordingly, heat is hardly transmitted between the outer part and the inner part of the electrode support 351 due to the action of the low heat transfer layer 356. Therefore, the refrigerant is controlled by the outer refrigerant channel 352 and the inner refrigerant channel 354, so that It is also possible to control the temperature so that the inner part is at a different temperature. Thus, the in-plane temperature of the upper electrode 350 can be controlled efficiently and accurately.

  In such a substrate processing apparatus 300, the wafer Tw is loaded via a gate valve by a transfer arm, for example. The wafer Tw carried into the processing chamber 310 is placed on the lower electrode 340, high frequency power is applied to the upper electrode 350 and the lower electrode 340, and a predetermined processing gas is passed from the upper electrode 350 into the processing chamber 310. Is introduced. As a result, the processing gas introduced from the upper electrode 350 is turned into plasma, and the surface of the wafer Tw is subjected to, for example, an etching process.

Reference light from the optical fiber coupler 220 in the temperature measuring device 200 is adapted to be transmitted reference beam transmission means for example via a collimator optical fiber with F _Z to the reference mirror 240 to the reference beam irradiation position to be irradiated. Further, the measurement light from the optical fiber coupler 220 is irradiated from above the electrode plate Tu of the upper electrode 350 toward the electrode plate Tu and the wafer Tw from the upper electrode 350 through the measurement light transmission means, for example, the optical fiber F with a collimator. It is transmitted to the measurement light irradiation position. Specifically, the optical fiber F with a collimator is irradiated with measurement light toward the electrode plate Tu and the wafer Tw through a through-hole 358 formed in, for example, the center of the electrode support 351 of the upper electrode 350. It is arranged.

  In addition, although the case where the position in the in-plane direction where the measurement light is radiated, that is, the position in the in-plane direction of the electrode plate Tu and the wafer Tw is the central portion has been described, the present invention is not limited to this. Any position may be used as long as it irradiates Tu and further passes through the electrode plate Tu and irradiates the wafer Tw.

  The control device 400 controls each part of the temperature measuring device 200 and the substrate processing device 300. The control device 400 includes a CPU (central processing unit) 410 constituting the main body, a motor controller 430 for controlling a stepping motor 242 for driving the reference mirror 240 via a motor driver 420, and program data for the CPU 410 to control each part. Through a memory 440 and a buffer 450 constituting a ROM (Read Only Memory) storing a memory, a RAM (Random Access Memory) provided with a memory area used for various data processing performed by the CPU 410, and the like. The A / D signal that is input after the analog-to-digital conversion of the output signal from the PD 250 (the measurement result of the interference wave obtained by irradiating the measurement light) and the control signal (for example, the drive pulse) output from the motor controller 430 are input. Controls each part of the D converter 460 and the substrate processing apparatus 300 Provided with a seed controller 470. The control device 400 may measure the moving position and moving distance of the reference mirror 240 based on a control signal (for example, a drive pulse) of the stepping motor 242 output from the motor controller 430. A linear encoder is attached to the motor 242. The moving position and moving distance of the reference mirror 240 may be measured based on the output signal from the linear encoder. Further, the motor 242 is not limited to a stepping motor, and a voice coil motor or the like may be used.

  According to the temperature measurement system having such a configuration, the reference mirror 240 scans the interference wave between the first and second measurement light reflected by the electrode plate Tu of the upper electrode 350 and the wafer Tw and the reference light once. Therefore, it is possible to measure the temperature of different measurement objects at once, such as the electrode plate Tu of the upper electrode 350 and the wafer Tw.

  Here, a specific example of light interference between the measurement light and the reference light obtained by the temperature measurement system shown in FIG. 5 is shown in FIG. FIG. 6 shows an interference waveform between the first and second measurement light reflected by the electrode plate Tu and the wafer Tw of the upper electrode 350 and the reference light reflected by the reference light reflecting means 140. In FIG. 6, the vertical axis represents the interference intensity, and the vertical axis represents the moving distance of the reference mirror.

  According to FIG. 6, when the reference mirror 240 is scanned in one direction, first, an interference wave appears between the surface of the electrode plate Tu of the upper electrode 350 and the reference light, and then the back surface of the electrode plate Tu of the upper electrode 350. Interference with reference light appears. As the reference mirror 240 is further scanned, an interference wave between the front surface of the wafer Tw and the reference light appears, and then an interference wave between the back surface of the wafer Tw and the reference light appears. As described above, the interference wave between the electrode plate Tu of the upper electrode 350 and the front and back surfaces of the wafer Tw can be detected at a time only by scanning the reference mirror 240 once.

  The peak-to-peak width Lu of the interference waveform between the front surface and the back surface of the electrode plate Tu of the upper electrode 350 corresponds to the optical path length of the measurement light from the front surface to the back surface of the electrode plate Tu of the upper electrode 350. Further, the peak-to-peak width Lw of the interference waveform between the front surface and the back surface of the wafer Tw corresponds to the optical path length of the measurement light from the front surface to the back surface of the wafer Tw. The peak-to-peak width Lg of the interference waveform between the back surface of the electrode plate Tu of the upper electrode 350 and the surface of the wafer Tw is the optical path of the measurement light in the gap (separation distance) between the electrode plate Tu of the upper electrode 350 and the wafer Tw. Corresponds to the length.

  The control device 400 determines the temperature of the electrode plate Tu of the upper electrode 350 and the wafer Tw according to the temperature conversion method as described above from the measurement result of the optical path length of the measurement light for the electrode plate Tu of the upper electrode 350 and the wafer Tw thus obtained. Ask for. Specifically, for example, the optical path length of the measurement light for the electrode plate Tu of the upper electrode 350 and the wafer Tw is converted into temperature based on the above-described reference data for temperature conversion stored in the memory 440 in advance.

  As described above, according to the temperature measurement system shown in FIG. 5, not only the electrode plate Tu of the upper electrode 350 but also the measurement light transmitted through the electrode plate Tu of the upper electrode 350 is used as the measurement light of the wafer Tw. As for the wafer Tw, an interference wave between the measurement light and the reference light can be obtained by scanning the reference mirror 240 once. Accordingly, the measurement light split from the SLD 210 is irradiated toward the electrode plate Tu and the wafer Tw of the upper electrode 350, and the electrode plate Tu and the wafer of the upper electrode 350 which are different measurement objects. The temperature of Tw can be detected at a time.

  Thereby, for example, it is easy to handle an optical fiber or the like, and it is possible to eliminate the need to form a hole in the electrode plate of the upper electrode 350, so that it is possible to reduce the trouble of mounting the temperature measuring device 200. In addition, since the temperature of the electrode plate Tu and the wafer Tw of the upper electrode 350 can be measured at one time with one temperature measuring device 200, the temperature measurement time can be shortened as much as possible while suppressing an increase in cost as much as possible.

(Temperature measurement system according to the third embodiment)
Next, a temperature measurement system for a substrate processing apparatus according to a third embodiment will be described with reference to the drawings. The temperature measurement system according to the third embodiment is configured by improving the temperature measurement system according to the second embodiment so that the moving distance of the reference mirror can be further shortened.

That is, the electrode plate Tu and the wafer Tw of the upper electrode 350 corresponding to the measurement target T ₁ and T ₂ in the temperature measurement system according to the second embodiment are separated by the amount of these gaps, in FIG. 6 As shown, the interference wave of the measurement light and the reference light on the electrode plate Tu of the upper electrode 350 and the interference wave of the measurement light and the reference light on the wafer Tw are also separated by the optical path length Lg of the gap (separation distance). Measured. Therefore, in order to measure the temperature of the electrode plate Tu of the upper electrode 350 and the wafer Tw by a single scan of the reference mirror 240, the reference mirror corresponds to the gap (separation distance) between the electrode plate Tu of the upper electrode 350 and the wafer Tw. The moving distance of 240 needs to be increased. However, the portion Lg of the gap (separation distance) is a portion that is not necessary for the temperature measurement of the electrode plate Tu of the upper electrode 350 and the wafer Tw, and therefore the time required for the temperature measurement can be shortened by making it as short as possible. it can.

  The temperature measurement system according to the third embodiment is improved based on this point. As an improvement, for example, by providing a bypass optical path connected in parallel to the optical path of the measurement light in the middle of the optical path of the measurement light that constitutes the measurement light transmission means, the measurement light that does not pass through the bypass optical path can be measured. Since both light beams are emitted toward the object to be measured, the pattern of interference between the measurement light and the reference light increases, and the optical path length of the detour optical path is adjusted to adjust the amount of interference of each light. As a result, only the interference waveform necessary for measurement can appear in the vicinity. Thereby, the moving distance of the reference mirror can be further shortened.

  Hereinafter, a specific configuration example of the temperature measurement system according to the third embodiment is shown in FIG. The measurement light transmission means in the temperature measurement system shown in FIG. 7 is a bypass optical path connecting splitter for connecting in parallel the optical fiber e constituting the bypass optical path in the middle of the optical path of the measurement light from the optical fiber coupler 220, for example 2 × Two optical fiber couplers 230 are provided. The optical fiber coupler 230 has the same configuration as the optical fiber coupler 220.

One output terminal (output port) from the optical fiber coupler 220 is connected to one input terminal (input port) of the optical fiber coupler 230 via the optical fiber b. To one output terminal of the optical fiber coupler 230 (the output port), an optical fiber b _F collimator optical fiber with F fitted with a collimator at the tip of the are connected. Further, the other input terminal (input port) and the other output terminal (output port) of the optical fiber coupler 230 connect the optical fiber e constituting the bypass optical path to form a loop.

According to the measurement light transmission means configured as shown in FIG. 7, the measurement light emitted from one output terminal (output port) from the optical fiber coupler 220 is transmitted to two output terminals (output ports) by the optical fiber coupler 230. Is demultiplexed into two. Of these, measurement light from one output terminal (output port) passes through the optical fiber b _F and is irradiated from the tip of the collimator-equipped optical fiber F toward the electrode plate Tu of the upper electrode 350 and the wafer Tw.

Further, the measurement light from the other output terminal (output port) of the optical fiber coupler 230 is returned to the other input terminal (input port) of the optical fiber coupler 230 via the optical fiber e. Divided into two output terminals (output ports). Of these, measurement light from one output terminal (output port) passes through the optical fiber b _F and is irradiated from the tip of the collimator-equipped optical fiber F toward the electrode plate Tu of the upper electrode 350 and the wafer Tw.

In this way, by providing a bypass optical path connected in parallel in the middle of the optical path of the measurement light that constitutes the measurement light transmission means, the measurement light split from the SLD 210 is transmitted from the optical fiber F with a collimator to the upper electrode 350. The optical fiber is used not only for the forward path irradiated toward the electrode plate Tu and the wafer Tw but also for the return path where the measurement light reflected from the electrode plate Tu and the wafer Tw of the upper electrode 350 is received via the optical fiber F with a collimator. or through the path via the optical path U ₁ in the coupler 230, so or through the path through the bypass optical path U ₂ by the optical fiber e, the optical path of the measuring beam is increased.

  Here, the optical path of such measurement light will be described with reference to the drawings. FIG. 8 shows the relationship between the type (pattern) of the optical path of the measurement light and the path of the measurement light at that time. As the measurement light path, the output path from the optical fiber coupler 220 to the irradiation to the electrode plate Tu of the upper electrode 350 and the wafer Tw and the measurement light reflected from the electrode plate Tu of the upper electrode 350 and the wafer Tw are reflected. There is a return path until it is input to the optical fiber coupler 220.

When the detour optical path as shown in FIG. 7 is formed, the types (patterns) of the optical paths of the measurement light are four combinations from the optical path A to the optical path D as shown in FIG. . Optical path A is a case where the measurement light passes through the path through the forward path and the backward path both optical path U _1, the optical path length is shortest optical path. Optical path B, the forward measurement light passes through a path through the optical path U _1, the return path is a case where through the path via the bypass optical path U _2. Optical path C is measurement light forward path through the path through the bypass optical path U _2, return is when passing through a path through the optical path U _1, is the same length as the optical path B as the optical path length. The optical path D is a case where the measurement light passes through the path through the detour optical path U _{2 in} both the forward path and the return path, and is the optical path having the longest optical path length.

  Here, FIG. 9 shows light interference between the measurement light and the reference light that have passed through the optical paths A to D. FIG. 9 shows an interference waveform obtained when the reference mirror is scanned only once in one direction. The horizontal axis represents the moving distance of the reference mirror, and the vertical axis represents the interference intensity. In FIG. 9, the light interference along the optical paths A to D is shifted up and down so that the light interference can be easily distinguished. In practice, a waveform obtained by synthesizing all the light interference waveforms along the optical paths A to D is measured. Is done.

  As shown in FIG. 9, the light interference along the optical paths A to D is similar to the case shown in FIG. 6 in that the interference wave between the front and back surfaces of the electrode plate Tu of the upper electrode 350 and the interference wave between the front and back surfaces of the wafer Tw. Appear with the same peak-to-peak widths Lu, Lg, and Lw. Therefore, the same measurement result can be obtained even if the light interferes with the measurement light passing through any one of the optical paths A to D. Therefore, for example, the peak-to-peak width Lw of the interference wave for the wafer Tw is obtained by light interference through the optical path A, and the peak-to-peak width Lu of the interference wave from the electrode plate Tu of the upper electrode 350 is obtained by light interference through the optical path B. It is also possible.

Furthermore, since the optical paths A to D have different optical path lengths, the light interference caused by the optical paths A to D is the optical path of the optical paths A to D before the interference wave on the surface of the electrode plate Tu of the first upper electrode 350 appears. Deviation according to length occurs. For example the first interference wave for the light interference due to the optical path A where the reference mirror 240 from the peak appears in (the interference wave of the surface of the electrode plate Tu of the upper electrode 350) is moved by a distance M _1, the optical path B and the optical path The peak of the first interference wave for the light interference by C appears. The first interference wave peak for the optical path D appears when the reference mirror 240 moves by the distance M _{2 after} the first interference wave peak for light interference by the optical path A appears. This is because the optical path length of the optical path A is the shortest, so the first interference wave with respect to the light interference by the optical path A appears most quickly, whereas the optical path lengths of the optical paths B, C, and D are longer than the optical path A. Therefore, the interference of these lights is shifted by the difference in the length of the optical path length, and the first interference wave appears. Since the optical path lengths of the optical path B and the optical path C are the same, the first interference wave regarding the interference of these lights appears simultaneously.

  Moreover, the amount of deviation of the light interference caused by the optical paths A to D is adjusted by adjusting the optical path length of the detour optical path of the measurement light (for example, the length of the optical fiber e). Can be adjusted. Therefore, by adjusting the optical path length of the detour optical path of the measurement light (for example, the length of the optical fiber e), the measurement light and the reference light for the electrode plate Tu of the upper electrode 350 and the wafer Tw are measured. Each interference waveform can be measured in the vicinity. For this reason, it is sufficient to move the reference mirror 240 at least within a range in which the interference waveform between the measurement light and the reference light with respect to the measurement object such as the electrode plate Tu of the upper electrode 350 and the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror can be shortened, the time required for temperature measurement can also be shortened.

  In this case, the optical path length of the detour optical path of the measurement light is adjusted so that the measurement object, for example, the electrode plate Tu of the upper electrode 350 and the peak width of the interference waveform with respect to the wafer Tw are all or partially overlapped. For example, since the moving distance of the reference mirror 240 can be further shortened, the time required for temperature measurement can be further shortened.

  As described above, according to the temperature measurement system shown in FIG. 7, when the reference mirror 240 is scanned in one direction by the stepping motor 242, an interference wave of light shifted according to the optical path lengths of the optical paths A to D is obtained. By adjusting the optical path length of the detour optical path of the measurement light, for example, as shown in FIG. 9, the entire peak width Lw of the interference waveform for the wafer Tw becomes the peak width of the interference waveform for the electrode plate Tu of the upper electrode 350. It can also be overlapped. In this way, if the reference mirror 240 is moved only within a range in which the inter-peak width Lu of the interference waveform with respect to the electrode plate Tu of the upper electrode 350 can be measured (for example, only in the range N shown in FIG. 9), Not only the peak-to-peak width Lu of the interference waveform for the electrode plate Tu but also the peak width Lw of the interference waveform for the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror 240 can be shortened, the time required for temperature measurement can also be shortened.

In the third embodiment, the case where the temperatures of the _two measurement objects T ₁ and T ₂ such as the electrode plate Tu of the upper electrode 350 and the wafer Tw are measured is taken as an example. However, the present invention is not limited to this. Instead, it can also be applied to temperature measurement of three or more measurement objects. In particular, since the moving distance of the reference mirror 240 increases as the gap (separation distance) between the measurement objects T _{1 to} T _n increases, in such a case, the temperature of each measurement object T _{1 to} T _n is measured. If the optical path length of the detour optical path of the measurement light is adjusted so that the inter-peak widths necessary for interference overlap, the moving distance of the reference mirror 240 can be shortened, and the time required for temperature measurement is also greatly reduced. can do. In this case, the detour optical path may be increased according to the number n of the measurement objects T _{1 to} T _n .

Further, the inter-peak widths of the interference waves required for measuring the temperatures of the measurement objects T _{1 to} T _n do not have to overlap all but may partially overlap. The peak-to-peak width of the interference wave necessary for temperature measurement of each measurement target T ₁ through T _n is not necessarily overlap, so as to parallel the vicinity without overlapping peak width of each interference wave Also good.

(Modification of the temperature measurement system according to the third embodiment)
Next, a modification of the temperature measurement system according to the third embodiment will be described with reference to the drawings. FIG. 10: is a block diagram which shows schematic structure about the modification of the temperature measurement system concerning 3rd Embodiment. The temperature measurement system shown in FIG. 10 is almost the same as that shown in FIG. 7, but the one shown in FIG. 7 uses an optical fiber coupler 230 to parallel the optical fiber e constituting the detour optical path in the optical path of the measurement light. 10 to form a loop, while the one shown in FIG. 10 has two splitters (for example, a 1 × 2 optical fiber coupler 232 and a 2 × 1 optical fiber coupler 234) as bypass path connecting splitters, The optical fiber e ₁ constituting the optical path of the measurement light and the optical fiber e ₂ constituting the bypass optical path are connected in parallel to form a loop. Thereby, also in the temperature measurement system shown in FIG. 10, a bypass optical path connected in parallel in the middle of the optical path of the measurement light constituting the measurement light transmission means can be provided in the same manner as shown in FIG.

More specifically, one output terminal (output port) from the optical fiber coupler 220 is connected to the input terminal (input port) of the 1 × 2 optical fiber coupler 232 shown in FIG. It is connected. The two output terminals (output ports) of the 1 × 2 optical fiber coupler 232 respectively have one end of a short optical fiber e ₁ forming a path U ₁ and a path U ₂ of a bypass optical path longer than the optical fiber e _1. and one end of the optical fiber e ₂ that forms is connected. The other end of the optical fiber e _{1 and} the other end of the optical fiber e ₂ are respectively connected to two input terminals (input ports) of a 2 × 1 optical fiber coupler 234. Optical fiber b _F collimator optical fiber with F fitted with a collimator to the tip of the output terminal (output port) of the 2 × 1 optical fiber coupler 234 is connected.

According to the measurement light transmission means configured as shown in FIG. 10, the measurement light emitted from one output terminal (output port) from the optical fiber coupler 220 is sent to two output terminals (output ports) by the optical fiber coupler 232. Is divided into two. Among these, the measurement light from one output terminal (output port) enters the input terminal (input port) of the optical fiber coupler 234 through the short optical fiber e ₁ . On the other hand, the measurement light from the other output terminal (output port) of the optical fiber coupler 232 enters the input terminal (input port) of the optical fiber coupler 234 through the optical fiber e ₂ constituting the bypass optical path. In the optical fiber coupler 234, the measurement light from the optical fiber e ₁ and the optical fiber e ₂ is multiplexed, is irradiated from the tip of the collimator optical fiber with F to the electrode plates Tu and the wafer Tw of the upper electrode 350.

Note that the relationship between the types of optical paths (optical paths A to D) of the measurement light by the measurement light transmission means configured as shown in FIG. 10 and the path of the measurement light at that time is the same as that shown in FIG. The light interference between the measurement light and the reference light when the light passes through the optical paths A to D is the same as that shown in FIG. That is, also in the temperature measurement system having the configuration shown in FIG. 10, the deviation amount of the interference between the measurement light and the reference light when passing through each of the optical paths A to D is the optical path length of the detour optical path of the measurement light (for example, optical fiber e ₁ and the length of the optical fiber e ₂ ) to adjust the optical path lengths of the optical paths A to D.

Therefore, by adjusting the optical path length of the detour optical path of the measurement light (for example, the length of the optical fiber e ₁ or the optical fiber e ₂ ), the measurement of each measurement object, for example, the electrode plate Tu and the wafer Tw of the upper electrode 350 is performed. The interference waveform between the light and the reference light can be measured in the vicinity, or all or part of the peak widths of these interference waveforms can be measured. For this reason, it is sufficient to move the reference mirror 240 at least within a range in which the interference waveform between the measurement light and the reference light with respect to the measurement object such as the electrode plate Tu of the upper electrode 350 and the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror can be shortened, the time required for temperature measurement can also be shortened.

Further, the optical fiber e constituting the bypass optical path shown in FIG. 7 described above connects the other input terminal (input port) and the other output terminal (output port) of one optical fiber coupler 230 to form a loop. Since it is formed, it is necessary to bend and arrange the optical fiber e, which may not be suitable depending on the length and thickness of the optical fiber. For example, when the optical fiber is short or thick, it is difficult to bend and arrange. On the other hand, the optical fiber e ₂ constituting the detour optical path shown in FIG. 10 is connected in the middle of the two optical fiber couplers 232 and 234, and therefore does not need to be bent extremely. Nevertheless, the arrangement is easy.

Moreover, in the case shown in FIG. 7, the optical path length of the measurement light is adjusted by adjusting the length of the optical fiber e constituting the bypass optical path, whereas in the case shown in FIG. 10, the bypass optical path is configured. Since not only the length of the optical fiber e ₂ to be measured but also the length of the optical path itself of the measurement light can be adjusted by the length of the optical fiber e ₁ , fine adjustment of the optical path lengths of the optical paths A to D of the measurement light is easy. Can be done.

(Measurement system according to the fourth embodiment)
Next, a temperature measurement system for a substrate processing apparatus according to a fourth embodiment will be described with reference to the drawings. The temperature measurement system according to the fourth embodiment is an improvement of the temperature measurement system according to the second embodiment, and further, the optical axis of the measurement light with respect to each measurement object is set regardless of the accuracy of the parallelism of each measurement object. It is configured so that it can be easily adjusted.

  That is, in the temperature measurement system according to the second embodiment, the measurement light split from the SLD 110 is irradiated by one optical fiber F with a collimator, and the measurement light reflected by the electrode plate Tu of the upper electrode 350 and the wafer Tw is received. Therefore, depending on the accuracy of the parallelism between the electrode plate Tu of the upper electrode 350 and the wafer Tw, it takes time to adjust the optical axis of the measurement light.

  The temperature measurement system according to the fourth embodiment is improved based on this point. As an improvement, the measurement light split from the light source is further split by the number of measurement objects, and these measurement lights are irradiated toward the measurement object. Thereby, since the optical axis of each measurement light can be adjusted for each measurement object, the optical axis of the measurement light can be easily adjusted regardless of the accuracy of the parallelism of each measurement object.

  FIG. 11 shows a specific configuration example of the temperature measurement system according to the fourth embodiment. In the temperature measurement system shown in FIG. 11, for example, measurement light split from the SLD 210 by a light source side splitter, for example, a 2 × 2 optical fiber coupler 220, is first measured by a measurement light splitter, for example, a 1 × 2 optical fiber coupler 236. The first measurement light is used for temperature measurement of the electrode plate Tu of the upper electrode 350 and the second measurement light is used for temperature measurement of the wafer Tw.

More specific description will be given below. One output terminal (output port) from the optical fiber coupler 220 is connected to one input terminal (input port) of the optical fiber coupler 236 via the optical fiber b. Each of the two output terminals of the optical fiber coupler 236 (the output port), a collimator and collimator optical fiber with F ₁ attached to the distal end of the optical fiber b _F1, a collimator with a light attached to the collimator at the tip of the optical fiber b _F2 and the fiber F ₂ are connected.

The collimator-equipped optical fiber F ₁ is arranged so that the first measurement light is irradiated toward the electrode plate Tu through a through hole 358 formed in the central portion of the electrode support 351 of the upper electrode 350. Further, the collimator-equipped optical fiber F ₂ is irradiated to the electrode plate Tu through the through hole 359 formed at the end of the electrode support 351 of the upper electrode 350 and transmitted through the electrode plate Tu. It arrange | positions so that measurement light may be irradiated to the wafer Tw.

In this way, the measurement light split from the SLD 210 is demultiplexed into the first measurement light for measuring the temperature of the electrode plate Tu of the upper electrode 350 and the second measurement light for measuring the temperature of the wafer Tw. Since the optical axis of the optical fiber F ₁ with collimator and the optical axis of the optical fiber F ₂ with collimator can be adjusted separately by irradiating from the tips of the fibers F ₁ and F ₂ , the electrode plate of the upper electrode 350 Regardless of the accuracy of the parallelism between Tu and the wafer Tw, the optical axis of each measurement light can be easily adjusted. This facilitates the installation of the collimator-equipped optical fiber, so that it is possible to reduce the trouble of mounting the temperature measuring device 200.

Further, since the measurement light split from the SLD 210 is demultiplexed into the first measurement light passing through the optical path E via the collimator-equipped optical fiber F ₁ and the second measurement light passing through the optical path F via the collimator-attached optical fiber F ₂ . The interference of light between the two types of measurement light and the reference light can be measured.

  Here, FIG. 12 shows light interference between the measurement light and the reference light that have passed through the optical paths E and F. FIG. 12 shows an interference waveform obtained when the reference mirror is scanned only once in one direction. The horizontal axis represents the moving distance of the reference mirror, and the vertical axis represents the interference intensity. In FIG. 12, the light paths E and F are shifted up and down so that the light interference can be easily distinguished. In practice, however, a waveform obtained by synthesizing all the light interference waveforms of the light paths E and F is measured. Is done.

The amount of deviation of the light interference caused by the optical paths E and F is adjusted by adjusting the lengths of the optical fibers b _F1 and b _F2 of the optical fibers F ₁ and F ₂ with collimators, for example. Adjustment is possible by adjusting the optical path length of F. In this way, by adjusting the optical path lengths of the optical paths E and F of the first and second measurement beams, the interference between the measurement beam and the reference beam for each measurement object, for example, the electrode plate Tu of the upper electrode 350 and the wafer Tw. Each waveform can be measured in the vicinity. For this reason, it is sufficient to move the reference mirror 240 at least within a range in which the interference waveform between the measurement light and the reference light with respect to the measurement object such as the electrode plate Tu of the upper electrode 350 and the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror can be shortened, the time required for temperature measurement can also be shortened.

  For example, by adjusting the optical path lengths of the optical paths E and F of the first and second measurement lights, the entire peak width Lw of the interference waveform for the wafer Tw is adjusted for the electrode plate Tu of the upper electrode 350 as shown in FIG. It is also possible to overlap the peak width of the interference waveform. In this way, if the reference mirror 240 is moved only within a range in which the peak-to-peak width Lu of the interference waveform with respect to the electrode plate Tu of the upper electrode 350 can be measured (for example, only in the range N shown in FIG. 12), Not only the peak-to-peak width Lu of the interference waveform for the electrode plate Tu but also the peak width Lw of the interference waveform for the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror 240 can be shortened, the time required for temperature measurement can be further shortened.

  If the optical paths E and F of the first and second measurement lights are made the same, the optical path lengths of the first and second measurement lights from the optical fiber coupler 236 to the electrode plate Tu of the upper electrode 350 become equal. Therefore, the interference between the measurement light and the reference light is the same as that shown in FIG. In this case, the temperature can be obtained by measuring the interference waveform between the measurement light and the reference light as in the case shown in FIG.

Further, in order to adjust the optical path lengths of the first and second measurement beams, as described above, instead of changing the lengths of the optical fibers b _F1 and b _F2 of the collimator-equipped optical fibers F ₁ and F ₂ , it may be adjusted by shifting the tip position of the collimator of the fiber F _1, F _2.

In the fourth embodiment, the case where the temperatures of the _two measuring objects T ₁ and T ₂ such as the electrode plate Tu of the upper electrode 350 and the wafer Tw are measured is taken as an example, but the present invention is not limited to this. Instead, it can also be applied to temperature measurement of three or more measurement objects. In this case, for example, the measurement light split from the SLD 210 by the number n of the measurement objects T _{1 to} T _n is further split into first to n-th measurement lights by a splitter (for example, a 1 × n optical fiber coupler). , transmitting these first to n measuring light measured object to be placed at the end _{(T 1} or _{T n)} each measurement object from _T 1 each measurement object toward the through T _{n T} 1 through T _n You may irradiate as you do. This facilitates adjustment of the optical axis of each of the first to n-th measurement lights regardless of the accuracy of the parallelism of the measurement objects T _{1 to} T _n .

In addition, since the moving distance of the reference mirror 240 becomes longer as the gap (separation distance) of each of the measurement objects T _{1 to} T _n becomes larger, the optical path length of the first to nth measurement light is adjusted in such a case. Thus, if the peak-to-peak widths of the interference waves necessary for measuring the temperatures of the measurement objects T _{1 to} T _n are overlapped, the moving distance of the reference mirror 240 can be shortened. Time can also be greatly reduced.

In this case, the peak-to-peak widths of the interference waves required for measuring the temperatures of the measurement objects T _{1 to} T _n do not have to overlap all but may partially overlap. The peak-to-peak width of the interference wave necessary for temperature measurement of each measurement target T ₁ through T _n is not necessarily overlap, so as to parallel the vicinity without overlapping peak width of each interference wave Also good.

(Temperature measurement system according to the fifth embodiment)
Next, a temperature measurement system for a substrate processing apparatus according to a fifth embodiment will be described with reference to the drawings. The temperature measurement system according to the fifth embodiment is configured by improving the temperature measurement system according to the second embodiment so that the moving distance of the reference mirror can be further shortened. In the third and fourth embodiments described above, the optical path length of the measurement light is adjusted, whereas in the fifth embodiment, the optical path length of the reference light is adjusted.

FIG. 13 shows a configuration example of such a temperature measurement system according to the fifth embodiment. In the temperature measurement system shown in FIG. 13, the reference mirror 240 is configured by a first reference mirror 244 and a second reference mirror 246 that have different reflection surface positions. Reference light from the reference light transmitting means such as optical fiber F _Z with collimator is a first and a collimator optical fiber with F _Z to the reference light irradiation position irradiated to both the second reference mirror 244 arranged, each reference receiving reference light reflected from the mirror 244, 246 in the same collimator optical fiber with _{F Z.}

According to the temperature measurement system with such a configuration, the reference to be irradiated with first and second reference mirror 244 by moving together by the stepping motor 242, is split from the collimator optical fiber with F _Z from SLD210 When the light is reflected by the reference mirror 240, the first reference light passing through the optical path G reflected from the first reference mirror 244 and the second reference light passing through the optical path H reflected from the first reference mirror 246. Since they are divided, it is possible to measure the light interference between the two types of measurement light and the reference light.

  Here, FIG. 14 shows light interference between the measurement light and the reference light that have passed through the optical paths G and H. FIG. 14 shows an interference waveform obtained when the reference mirror 240 is scanned only once in one direction together with the first and second reference mirrors 244 and 246. The horizontal axis represents the moving distance of the reference mirror, and the vertical axis represents the interference intensity. In FIG. 14, each of the light paths G and H is shifted up and down so that the light interference can be easily distinguished. In practice, however, a waveform obtained by synthesizing all the light interference waveforms of the light paths G and H is measured. Is done.

  As shown in FIG. 14, the interference of light by the optical paths G and H is caused by the interference wave between the surface and the back surface of the electrode plate Tu of the upper electrode 350 and the interference wave between the surface and the back surface of the wafer Tw as in the case shown in FIG. It appears with the same peak-to-peak widths Lu, Lg, and Lw. Accordingly, the same measurement result can be obtained by interference of any of the light paths G and H.

  In addition, the amount of optical interference shift M due to each of the optical paths G and H is adjusted, for example, by adjusting the amount of shift of the reflecting surfaces of the reference mirrors 244 and 246 to obtain the optical path lengths of the optical paths G and H of the first and second reference waves. It can be adjusted by adjusting. In this way, by adjusting the optical path lengths of the optical paths G and H of the first and second reference lights, interference between the measurement light and the reference light for each measurement object, for example, the electrode plate Tu of the upper electrode 350 and the wafer Tw. Each waveform can be measured in the vicinity. For this reason, it is sufficient to move the reference mirror 240 at least within a range in which the interference waveform between the measurement light and the reference light with respect to the measurement object such as the electrode plate Tu of the upper electrode 350 and the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror can be shortened, the time required for temperature measurement can also be shortened.

  For example, by adjusting the optical path lengths of the first and second reference light paths G and H, as shown in FIG. 14, the entire peak width Lw of the interference waveform for the wafer Tw is the same for the electrode plate Tu of the upper electrode 350. It is also possible to overlap the peak width of the interference waveform. In this way, if the reference mirror 240 is moved only within a range in which the peak-to-peak width Lu of the interference waveform for the electrode plate Tu of the upper electrode 350 can be measured (for example, only in the range N shown in FIG. 14), Not only the peak-to-peak width Lu of the interference waveform for the electrode plate Tu but also the peak width Lw of the interference waveform for the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror 240 can be shortened, the time required for temperature measurement can be further shortened.

In the fifth embodiment, the case where the temperatures of the _two measuring objects T ₁ and T ₂ such as the electrode plate Tu of the upper electrode 350 and the wafer Tw are measured is taken as an example. However, the present invention is not limited to this. Instead, it can also be applied to temperature measurement of three or more measurement objects. In this case, for example, the reference mirror 240 is composed of first to n-th reference mirrors whose reflection surfaces are different by the number n of the measurement objects T _{1 to} T _n , and the reference light is referred to for the first to n-th references. You may make it irradiate all the mirrors and may obtain the 1st-nth reference lights reflected by each 1st-nth reference mirror.

Also, the larger the gap (distance) of each measurement target T ₁ through T _n, the movement distance of the reference mirror 240 becomes longer, the temperature measurement of each measurement target T ₁ through T _n in this case If the optical path lengths of the first to nth reference lights are adjusted so that the inter-peak widths necessary for interference overlap, the moving distance of the reference mirror 240 can be shortened, and the time required for temperature measurement is also increased. It can be greatly shortened.

In this case, the peak-to-peak widths of the interference waves required for measuring the temperatures of the measurement objects T _{1 to} T _n do not have to overlap all but may partially overlap. The peak-to-peak width of the interference wave necessary for temperature measurement of each measurement target T ₁ through T _n is not necessarily overlap, so as to parallel the vicinity without overlapping peak width of each interference wave Also good.

(Modification of Temperature Measurement System According to Fifth Embodiment)
Next, a modification of the temperature measurement system according to the fifth embodiment will be described with reference to the drawings. FIG. 15: is a block diagram which shows schematic structure about the modification of the temperature measurement system concerning 5th Embodiment. The temperature measurement system shown in FIG. 15 is substantially the same as that shown in FIG. 13, but the one shown in FIG. 13 adjusts the optical path lengths of the first and second reference lights by shifting the reflection surface of the reference mirror. On the other hand, in the example shown in FIG. 15, the reference light split from the SLD 210 by the light source side splitter, eg, 2 × 2 optical fiber coupler 220, is converted into the first light by the reference light splitter, eg, 1 × 2 optical fiber coupler 222. The reference light and the second reference light are divided into two, and the reference mirror 240 is irradiated with the first and second reference lights to receive the reflected light. The optical path length of the first and second reference lights Adjust.

More specifically, the other output terminal (output port) from the optical fiber coupler 220 is connected to the input terminal (input port) of the 1 × 2 optical fiber coupler 222 shown in FIG. It is connected. Mounting each of the 1 × 2 of two output terminals of the optical fiber coupler 222 (output port), the optical fiber c collimator optical fiber with F _Z1 fitted with a collimator tip of _Z1, a collimator at the tip of the optical fiber c _Z2 The collimator-equipped optical fiber _FZ2 is connected.

According to the reference light transmission means configured as shown in FIG. 15, the measurement light emitted from the other output terminal (output port) from the optical fiber coupler 220 is output by the optical fiber coupler 222 to two output terminals (output ports). Is demultiplexed into two. Of these, the first reference light from one output terminal (output port) is irradiated toward the reference mirror 240 by the optical path G through the collimator-equipped optical fiber _FZ1, and the second reference from the other output terminal (output port). The light is irradiated toward the reference mirror 240 by the optical path H through the collimator-equipped optical fiber _FZ2 .

Note that the interference between the reference light and the measurement light by the reference light transmission unit configured as shown in FIG. 15 is the same as that shown in FIG. That is, also in the temperature measurement system having the configuration shown in FIG. 15, the deviation amount M of the light interference caused by the optical paths G and H is, for example, the length of the optical fibers c _Z1 and c _Z2 of the optical fibers F _Z1 and F _Z2 with collimators. Is adjusted to adjust the optical path lengths of the optical paths G and H of the first and second reference waves.

Accordingly, by adjusting the optical path lengths of the first and second reference beams (for example, the lengths of the optical fibers c _Z1 and c _Z2 ), measurement is performed on each measurement object, for example, the electrode plate Tu and the wafer Tw of the upper electrode 350. The interference waveform between the light and the reference light can be measured in the vicinity, or all or part of the peak widths of these interference waveforms can be measured. For this reason, it is sufficient to move the reference mirror 240 at least within a range in which the interference waveform between the measurement light and the reference light with respect to the measurement object such as the electrode plate Tu of the upper electrode 350 and the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror can be shortened, the time required for temperature measurement can also be shortened.
(Other Modifications of Temperature Measurement System According to Fifth Embodiment)

  Next, another modification of the temperature measurement system according to the fifth embodiment will be described with reference to the drawings. In the third embodiment described above, a bypass optical path connected in parallel with the optical path of the measurement light is provided in the middle of the optical path of the measurement light that constitutes the measurement light transmission means. In another modification, a bypass optical path connected in parallel is provided in the middle of the optical path of the reference light constituting the reference light transmission means.

  Even in this configuration, since both the reference light passing through the detour optical path and the reference light not passing through are radiated toward the reference mirror 240, the measurement light and the reference light are similar to those in the third embodiment. By increasing the optical interference pattern and adjusting the optical path length of the detour optical path to adjust the shift amount of each optical interference, only the interference waveform necessary for the measurement can appear in the vicinity. Thereby, the moving distance of the reference mirror can be further shortened.

  A specific configuration of a temperature measurement system according to another modification of the fifth embodiment will be described below with reference to FIG. 16 or FIG. The temperature measurement system shown in FIG. 16 is an example in which a bypass optical path is connected as in the case shown in FIG. That is, the reference light transmission means in the temperature measurement system shown in FIG. 16 is a bypass optical path connecting splitter for connecting in parallel the optical fiber e constituting the bypass optical path in the middle of the optical path of the reference light from the optical fiber coupler 220. A 2 × 2 optical fiber coupler 230 is provided.

Specifically, the other output terminal (output port) from the optical fiber coupler 220 is connected to one input terminal (input port) of the optical fiber coupler 230 via the optical fiber c. To one output terminal of the optical fiber coupler 230 (the output port), the optical fiber c _Z tip collimator optical fiber with F _Z fitted with collimator the are connected. Further, the other input terminal (input port) and the other output terminal (output port) of the optical fiber coupler 230 connect the optical fiber e constituting the bypass optical path to form a loop.

According to the reference light transmission means configured as shown in FIG. 16, the reference light emitted from the other output terminal (output port) from the optical fiber coupler 220 is output by the optical fiber coupler 230 to two output terminals (output ports). Is divided into two. Reference light from these one output terminal (output port) is irradiated from the tip of the optical fiber F _Z with collimator to the reference mirror 240 passes through the optical fiber c _Z. Further, the reference light from the other output terminal (output port) of the optical fiber coupler 230 is returned to the other input terminal (input port) of the optical fiber coupler 230 via the optical fiber e. Divided into two output terminals (output ports). Reference light from these one output terminal (output port) is irradiated from the tip of the optical fiber F _Z with collimator to the reference mirror 240 passes through the optical fiber c _Z.

On the other hand, the temperature measurement system shown in FIG. 17 is an example in which a bypass optical path is connected as in the case shown in FIG. In other words, the bypass optical path is composed of two splitters (for example, 1 × 2 optical fiber coupler 232 and 2 × 1 optical fiber coupler 234) as bypass optical path connecting splitters, and the optical fiber e ₁ that forms the optical path of the reference light. by connecting the optical fiber e ₂ in parallel to form a loop. Thereby, also in the temperature measurement system shown in FIG. 17, it is possible to provide a detour optical path connected in parallel in the middle of the optical path of the reference light that constitutes the reference light transmission means, similarly to that shown in FIG.

More specifically, the other output terminal (output port) from the optical fiber coupler 220 is connected to the input terminal (input port) of the 1 × 2 optical fiber coupler 232 shown in FIG. It is connected. The two output terminals (output ports) of the 1 × 2 optical fiber coupler 232 respectively have one end of a short optical fiber e ₁ forming a path U ₁ and a path U ₂ of a bypass optical path longer than the optical fiber e _1. and one end of the optical fiber e ₂ that forms is connected. The other end of the optical fiber e _{1 and} the other end of the optical fiber e ₂ are respectively connected to two input terminals (input ports) of a 2 × 1 optical fiber coupler 234. 2 × 1 optical fiber c _Z tip collimator optical fiber with F _Z fitted with collimator to the output terminal (output port) of the optical fiber coupler 234 is connected.

According to the reference light transmission means configured as shown in FIG. 17, the reference light emitted from the other output terminal (output port) from the optical fiber coupler 220 is output by the optical fiber coupler 232 to two output terminals (output ports). Is demultiplexed into two. Reference light from these one of the output terminals (output ports) through the short optical fiber e ₁ incident on the input terminal of the optical fiber coupler 234 (input port). On the other hand, the reference light from the other output terminal (output port) of the optical fiber coupler 232 enters the input terminal (input port) of the optical fiber coupler 234 through the optical fiber e ₂ constituting the bypass optical path. In the optical fiber coupler 234, the reference light from the optical fiber e ₁ and the optical fiber e ₂ is multiplexed, is irradiated from the tip of the collimator optical fiber with F _Z to the reference mirror 240.

If the types of the optical paths of the reference light by the reference light transmission means having the configuration shown in FIG. 16 or FIG. 17 as described above are optical paths A to D, the relationship between these optical paths A to D and the path of the reference light at that time is The light interference between the measurement light and the reference light when the reference light passes through the optical paths A to D is the same as that shown in FIG. That is, also in the temperature measurement system having the configuration shown in FIG. 16 or FIG. 17, the deviation amount of the interference between the measurement light and the reference light when passing through each of the optical paths A to D is the optical path length of the detour optical path of the reference light ( For example, adjustment is possible by adjusting the optical path length of the optical paths A to D by adjusting the optical fiber e or the length of the optical fibers e ₁ and e ₂ .

Therefore, by adjusting the optical path length of the detour optical path of the reference light (for example, the length of the optical fiber e or the optical fibers e ₁ and e ₂ ), each measurement object, for example, the electrode plate Tu and the wafer Tw of the upper electrode 350 The interference waveform between the measurement light and the reference light can be measured in the vicinity, or all or part of the peak widths of these interference waveforms can be measured. For this reason, it is sufficient to move the reference mirror 240 at least within a range in which the interference waveform between the measurement light and the reference light with respect to the measurement object such as the electrode plate Tu of the upper electrode 350 and the wafer Tw can be measured. Thereby, since the moving distance of the reference mirror can be shortened, the time required for temperature measurement can also be shortened.

(Temperature measurement system that does not use optical fiber)
The temperature measurement system shown in the third to fifth embodiments described above uses an optical fiber as the measurement light transmission means and the reference light transmission means, and transmits light such as measurement light and reference light used in the temperature measurement to the optical fiber. However, the present invention is not necessarily limited to this, and the principle as shown in FIG. 18 is used without using optical fiber or collimated fiber for measuring light or reference light used for temperature measurement. The air may be transmitted based on the above.

FIG. 18 shows the principle of a temperature measuring apparatus 500 that transmits light using the air without using an optical fiber or a collimating fiber. In such a temperature measuring device 500, light from a light source (for example, SLD) 110 is transmitted through the air and irradiated onto a splitter (for example, half mirror) 510, and is split into reference light and measuring light by the splitter 510. It is done. The measurement light is transmitted to the measurement objects T ₁ and T ₂ arranged opposite to each other through the air, and is reflected by the front and back surfaces of the measurement objects T ₁ and T ₂ . On the other hand, the reference light is transmitted through the air and irradiated onto the reference light reflecting means (for example, the reference mirror) 140, and is reflected by the mirror surface of the reference light reflecting means. The reflected measurement light and reference light are transmitted through the air, enter the splitter 510 again, and are received by the light receiving means 150. At that time, depending on the optical path length of the reference light, they overlap and cause interference, and the interference wave is detected by the light receiving means 150. By using such a principle, light can be transmitted without using an optical fiber or a collimating fiber. As a result, even light having a wavelength that does not pass through the optical fiber or collimate fiber (for example, a wavelength of 2.5 μm or more) can be used as the light source 110 for measurement light or reference light.

(Control system for substrate processing equipment)
Further, in the temperature measurement system shown in the third to fifth embodiments described above, the controller for controlling the temperature of the electrode plate Tu of the upper electrode 350 and the temperature of the wafer Tw, for example, as the various controllers 470 is provided. The temperature measurement apparatus 200 can be used to measure the temperature of the Tu or wafer Tw, and the controller 470 can control the temperature according to the measurement result.

  In this case, the various controllers 470 may include, for example, an inner refrigerant controller and an outer refrigerant controller as those for controlling the temperature of the electrode plate Tu of the upper electrode 350. The inner refrigerant controller controls the temperature of the inner part of the upper electrode 350 by controlling the temperature and flow rate of the refrigerant circulated to the inner refrigerant flow path 354. The outer refrigerant controller controls the temperature of the outer portion of the upper electrode 350 by controlling the temperature and flow rate of the refrigerant circulated to the outer refrigerant flow path 352.

Furthermore, the various controllers 470 control the temperature of the wafer Tw, for example, ESC (electrostatic)
A chuck (electrostatic chuck) system controller and an FR (focus ring) system controller may be provided. The ESC system controller applies a voltage applied to an electrostatic chuck (ESC) (not shown) for electrostatically attracting the wafer to the lower electrode 340, the gas flow rate of the backside gas supplied to the wafer Tw via the electrostatic chuck, and the gas The pressure and the temperature of the refrigerant to be circulated through the refrigerant flow path formed in the lower electrode 340 are controlled. Further, the FR system controller includes a voltage applied to a peripheral ring (not shown) provided to surround the periphery of the wafer, for example, a focus ring, a gas flow rate and a gas pressure of a backside gas supplied to the wafer Tw via the focus ring, and the like. Is to control.

  Thus, by configuring the temperature measurement system shown in the third to fifth embodiments as a control system for the substrate processing apparatus, the temperature of the upper electrode 350 or the temperature of the wafer Tw can be controlled. The process characteristics of the wafer Tw can be accurately controlled, and the stability of the substrate processing apparatus can be improved.

(Thickness measuring device and thickness measuring system)
In the first to fifth embodiments, the case where the temperature of the measurement object is measured has been described. However, the present invention is not necessarily limited to this, and is applicable to the case where the thickness of the measurement object is measured. May be. That is, in the first to fifth embodiments, for example, it is utilized that the peak-to-peak width of the interference waveform between the measurement light reflected by the front and back surfaces of the measurement object and the reference light corresponds to the optical path length of the measurement object. Then, the case where the inter-peak width of the interference waveform is measured as the moving distance of the reference light reflecting means (for example, the reference mirror) to determine the optical path length of the measurement object, and this optical path length is converted into the temperature of the measurement object will be described. did.

  However, since this optical path length L is expressed by thickness d × refractive index n and refractive index n depends on temperature, if the refractive index n at the temperature when the optical path length L is measured is known, the measured optical path length L Is divided by the refractive index n to obtain the thickness d of the object to be measured. Therefore, for example, the relationship between the temperature of the measurement object and the refractive index n is previously stored in the memory 440 of the control device 400 as thickness reference conversion data, and the temperature when the optical path length L of the measurement object is measured is calculated. Measured by another temperature measuring means (for example, resistance thermometer, fluorescent thermometer, etc.), the refractive index n at that temperature is obtained from the reference conversion data for thickness, and the optical path length L is divided by this refractive index n. By doing so, the thickness d of the measurement object can be obtained.

  Thus, since the thickness of the measurement object can be obtained using the interference waveform between the measurement light and the reference light, the temperature measurement device according to the first to fifth embodiments can be obtained by using this principle. The temperature measuring system of the substrate processing apparatus can also be configured as a thickness measuring apparatus and a thickness measuring system of the substrate processing apparatus, respectively. By measuring the thickness of consumable parts such as the electrode plate Tu of the upper electrode 350 of the substrate processing apparatus 300 by using the thickness measuring system and the thickness measuring system of the substrate processing apparatus 300, the electrode plate Tu The amount of consumption of consumable parts such as can be measured. Thereby, it is also possible to predict the replacement time of the electrode plate Tu.

  The thickness is measured when the substrate processing apparatus 300 is in the same temperature state, such as when the power is turned on or after maintenance, and the refractive index n at that temperature is stored in the memory 440 of the control apparatus 400 or the like. If it is memorized, it is not necessary to measure the temperature of the object to be measured each time the thickness is measured, so there is no need for another temperature measuring means, and the time and labor for measuring the thickness are also eliminated. It can be reduced as much as possible. In addition, by causing the control device 400 to function as a thickness calculating unit or a control unit, the thickness of each measurement object can be obtained by the control device 400 based on the result of interference measurement between the measurement light and the reference light. it can.

  In addition, a plurality of measurement objects to be measured for temperature or thickness according to the present invention may be separated from each other or may be in contact with each other as long as they are arranged to face each other. In addition, the whole of the plurality of measurement objects may be opposed, or a part thereof may be opposed. When a part is opposed, the temperature or thickness of each measurement object can be measured by irradiating measurement light toward at least the opposite part.

(Light intensity of light source)
Further, as described in the above embodiment, in the present invention, when a plurality of measurement objects arranged opposite to each other are irradiated with the measurement light, the light transmitted through the measurement object is changed to the measurement light of the next measurement object. Use as Accordingly, the light intensity of such a measuring light to reduce transmitted through the space between the internal and the measured object T ₁ through T _n of each measured object T ₁ through T _n, such measurement light The interference intensity of the reference light also decreases, and the light intensity (S / N ratio) against noise also decreases. Moreover, the light intensity of the measurement light tends to decrease as the number n of measurement objects through which the measurement light passes increases and as the measurement object is farther from the measurement light irradiation position. For example, the light intensity of the measurement light reflected from the first measurement object among the first measurement objects arranged opposite to each other is the highest, and the light intensity of the measurement light reflected from the second and subsequent measurement objects gradually decreases. I will do it.

  As described above, since the light intensity of the measurement light decreases as the measurement light passes through the inside of each measurement object and the space between the measurement objects, the interference waveform between the measurement light and the reference light is accordingly reduced. The light intensity (S / N ratio) with respect to the noise decreases and the interference waveform is broken (for example, the shape of the interference waveform is away from the Gaussian distribution), and for example, the detection accuracy of the peak position decreases. For this reason, the measurement accuracy of the temperature measured based on the peak-to-peak width of the interference waveform also decreases. Note that the noise referred to here may be, for example, noise generated from an electronic circuit or noise due to the surrounding electromagnetic environment when high frequency power is applied to the upper electrode 350.

  Therefore, the temperature measuring device 100 or 200 is provided with a light intensity adjusting unit that can adjust the light intensity of the light source 110 such as an SLD 210, for example, and the light intensity adjusting unit is provided by the control device 400 via, for example, a light intensity controller provided in various controllers. The light intensity of the light source 110 may be changed during measurement of light interference between the measurement light and the reference light.

By doing so, during the measurement of the interference of light and the measurement light and the reference light, the measuring light is transmitted through the interior and the space between the measured object T ₁ through T _n of each measured object T ₁ through T _n By preventing a decrease in the light intensity of the measurement light due to this, it is possible to prevent a decrease in the S / N ratio with respect to the interference waveform between the measurement light and the reference light so that the interference waveform does not collapse. Thereby, for example, since the detection accuracy of the peak position of the interference waveform can be improved, the measurement accuracy of temperature and thickness based on the peak-to-peak width of the interference waveform can be improved.

  As a more specific light intensity adjustment method of the light source, for example, during the measurement of the light interference between the measurement light and the reference light, the light intensity of the light source is adjusted according to the moving distance of the reference light reflecting means (for example, the reference mirror) 140. Increasing gradually. According to this, since the light intensity can be increased as the measurement object is farther from the measurement light irradiation position, it is possible to prevent a decrease in the S / N ratio of the interference waveform between the measurement light and the reference light. it can.

Further, during the measurement of the light interference between the measurement light and the reference light, the light intensity of the light source may be changed for each of the measurement objects T _{1 to} T _n . Since the light intensity of the measuring light varies for each measurement target T ₁ through T _n, by changing the light intensity of the light source for each measurement target T ₁ through T _n, accurately decrease in light intensity of the measuring light Can be prevented.

  For example, the reflection intensity of the measurement light from each measurement object is measured in advance, and when measuring the interference between the measurement light of each measurement object and the reference light, the reflection intensity of the measurement light measured in advance (for example, By changing the light intensity of the light source according to the interference intensity of the interference waveform between the measurement light and the reference light, the light intensity of the light source can be increased as the measurement light reflection intensity decreases. A decrease in the S / N ratio of the interference waveform with light can be accurately prevented.

Further, during the measurement of the light interference between the measurement light and the reference light, the light intensity of the light source is increased as the measurement object is distant from the measurement light irradiation position for each measurement object T _{1 to} T _n. Also good. As a result, the number of measurement objects through which the measurement light is transmitted, that is, the number of measurement objects between the arrangement position of the measurement object to be measured and the measurement light irradiation position is large. Since the light intensity can be increased, it is possible to accurately prevent a decrease in the S / N ratio of the interference waveform between the measurement light and the reference light. For example, as described above, when measuring the electrode plate Tu of the upper electrode 350 and the wafer Tw at a time as the measurement object, when measuring the interference waveform between the measurement light and the reference light on the electrode plate Tu of the upper electrode 350. Rather, the light intensity of the light source is increased when measuring the interference wave between the measurement light and the reference light for the wafer Tw. As a result, the light intensity of the measurement light for measuring the wafer Tw is also increased, so that a decrease in the S / N ratio of the interference waveform between the measurement light and the reference light for the wafer Tw can be prevented.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are of course within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, the wafer Tw to be processed in the processing chamber 310 of the substrate processing apparatus 300 is described as an example of the substrate to be measured as the measurement target. The substrate to be processed may be a liquid crystal substrate such as a glass substrate.

  In the above-described embodiment, the electrode plate Tu of the upper electrode 350 disposed in the processing chamber 310 of the substrate processing apparatus 300 is described as an example of the electrode plate to be a measurement object. The plate may be an electrode plate of the lower electrode 340. Since the electrode plate of the lower electrode 340 is disposed not only on the substrate to be processed, for example, the wafer Tw but also on the electrode plate Tu of the upper electrode 350, the electrode plate Tu of the upper electrode 350 in the configuration of the above embodiment. The temperature or thickness of the electrode plate of the wafer Tw and the lower electrode 340 can be measured at a time.

  Furthermore, the measurement object is not limited to a wafer or an electrode plate arranged in the substrate processing apparatus, and various components and components in the substrate processing apparatus can be measured as long as they are arranged facing each other. The temperature or thickness of the object can be measured at a time. For example, a peripheral ring (for example, a focus ring) disposed around the wafer is also disposed so as to face the electrode plate. Therefore, the temperature or thickness of the peripheral ring and the electrode plate can be measured at the same time. Can be measured.

  In the above embodiment, the case where the substrate processing apparatus is applied to, for example, a plasma processing apparatus has been described. However, the present invention is not necessarily limited to this, and film modification such as a film forming apparatus or a heat treatment apparatus that does not use plasma. The temperature / thickness measuring apparatus according to the present invention is not limited to the substrate processing apparatus and can be applied to various other processing apparatuses.

  The present invention can be applied to, for example, a temperature / thickness measuring apparatus, a temperature measuring method, and a temperature / thickness measuring system for measuring the temperature of a semiconductor wafer, a liquid crystal substrate, etc., and a control system and control for controlling a substrate processing apparatus Applicable to the method.

It is a block diagram showing a schematic structure of a temperature measuring device concerning a 1st embodiment of the present invention. It is a block diagram which shows schematic structure of the temperature measuring apparatus concerning a comparative example. It is a figure which shows the specific example of the interference wave of the light of the measurement light and reference light which are obtained by the temperature measuring device concerning the embodiment, The figure (a) is the light before the temperature of each temperature measurement object changes FIG. 2B shows an example of the interference wave of light after the temperature of each temperature measurement object has changed. It is an experimental result which shows the specific example of the relationship between the temperature of a measuring object, and optical path length. It is a block diagram which shows schematic structure about the specific example of the temperature measurement system of the substrate processing apparatus concerning 2nd Embodiment of this invention. It is a figure which shows the specific example of the interference wave of the light of the measurement light and reference light which are obtained with the temperature measuring device concerning the embodiment. It is a block diagram which shows schematic structure about the specific example of the temperature measurement system of the substrate processing apparatus concerning 3rd Embodiment of this invention. It is a figure which shows the kind of optical path of the measurement light by the temperature measuring device concerning the embodiment. It is a figure which shows the specific example of the interference wave of the light of the measurement light and reference light which are obtained with the temperature measuring device concerning the embodiment. It is a block diagram which shows schematic structure about the modification of the temperature measurement system of the substrate processing apparatus concerning the embodiment. It is a block diagram which shows schematic structure about the specific example of the temperature measurement system of the substrate processing apparatus concerning 4th Embodiment of this invention. It is a figure which shows the specific example of the interference wave of the light of the measurement light and reference light which are obtained with the temperature measuring device concerning the embodiment. It is a block diagram which shows schematic structure about the specific example of the temperature measurement system of the substrate processing apparatus concerning 5th Embodiment of this invention. It is a figure which shows the specific example of the interference wave of the light of the measurement light and reference light which are obtained with the temperature measuring device concerning the embodiment. It is a block diagram which shows schematic structure about the modification of the temperature measurement system of the substrate processing apparatus concerning the embodiment. It is a block diagram which shows schematic structure about the other modification of the temperature measurement system of the substrate processing apparatus concerning the embodiment. It is a block diagram which shows schematic structure about the other modification of the temperature measurement system of the substrate processing apparatus concerning the embodiment. It is a figure for demonstrating the principle of the temperature measurement apparatus which transmits light, such as measurement light and reference light, using the air. It is a figure for demonstrating the principle of the conventional temperature measuring apparatus. FIG. 20 is a diagram conceptually showing an interference waveform measured by the temperature measuring device shown in FIG. 19.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Temperature measuring apparatus 102 Temperature measuring apparatus 110 Light source 120 Splitter 132 Optical communication multiplexer 140 Reference light reflecting means 142 Driving means 150 Light receiving means 200 Temperature measuring apparatus 210 SLD
220 Optical fiber coupler (splitter)
222 Optical fiber coupler (splitter for reference light)
230 Optical fiber coupler (diverter optical path connection splitter)
232 Optical fiber coupler (diverter optical path splitter)
234 Optical fiber coupler (diverter optical path splitter)
236 Optical fiber coupler (splitter for measuring light)
240 Reference mirror 242 Motor 244 First reference mirror 246 Second reference mirror 250 PD
300 substrate processing apparatus 310 processing chamber 320 high frequency power supply 330 high frequency power supply 340 lower electrode 350 upper electrode 351 electrode support 352 outer refrigerant flow path 354 inner refrigerant flow path 356 low heat transfer layer 358 through hole 359 through hole 400 control apparatus 410 CPU
420 Motor driver 430 Motor controller 440 Memory 470 Various controllers 500 Temperature measuring device 510 Splitter

Claims (36)

A temperature / thickness measuring device for measuring the temperature or thickness of a plurality of measurement objects arranged opposite to each other based on light interference,
A light source that emits light having a wavelength that passes through and reflects each measurement object;
A splitter for splitting light from the light source into measurement light and reference light;
Reference light reflecting means for reflecting reference light from the splitter;
An optical path length changing means for changing an optical path length of the reference light reflected from the reference light reflecting means;
Reference light transmission means for transmitting the reference light from the splitter to a reference light irradiation position for irradiating the reference light to the reference light reflection means;
Measuring light transmission means for transmitting the measurement light from the splitter to the measurement light irradiation positions for irradiating the plurality of measurement objects so as to pass through the measurement objects;
A light receiving means for measuring light interference between each measurement light reflected from each measurement object and reference light reflected from the reference light reflecting means;
A temperature / thickness measuring apparatus comprising: 2. The temperature / thickness measuring apparatus according to claim 1, wherein the measuring light transmission means includes a bypass optical path connected in parallel with the measuring light optical path in the middle of the measuring light optical path. The optical path length of the detour optical path of the measurement light is adjusted so that an interference waveform between the measurement light and the reference light for each measurement object is measured in the vicinity. Temperature / thickness measuring device. The optical path length of the detour optical path of the measurement light is adjusted so that all or part of the peak widths of the interference waveform between the measurement light and the reference light for each measurement object overlap each other. The temperature / thickness measuring apparatus according to claim 3. A measuring light splitter is provided for further splitting the measuring light from the splitter into a plurality of measuring lights, and each measuring light from the measuring light splitter is directed toward the plurality of measuring objects. 2. The temperature / thickness measuring apparatus according to claim 1, wherein the irradiation is performed so as to pass through. The reference light reflecting means is provided with a plurality of reflecting surfaces, and the reference light from the splitter is reflected by the reflecting surfaces so that a plurality of reference lights having different optical path lengths can be reflected. Item 2. The temperature / thickness measuring apparatus according to Item 1. The position of a plurality of reflection surfaces of the reference light reflecting means is adjusted so that interference waveforms of the measurement light and the reference light for each measurement object are measured in the vicinity. 6. The temperature / thickness measuring apparatus according to 6. The positions of the plurality of reflecting surfaces of the reference light reflecting means were adjusted so that all or part of the peak widths of the interference waveform between the measurement light and the reference light for each measurement object overlapped and measured. The temperature / thickness measuring apparatus according to claim 7, wherein A reference light splitter for further splitting the reference light from the splitter into a plurality of reference lights is provided, and the reference light reflecting means is irradiated with the reference light from the reference light splitter. Item 2. The temperature / thickness measuring apparatus according to Item 1. The optical path lengths of the plurality of reference lights from the reference light splitter are adjusted so that interference waveforms of the measurement light and the reference light for each measurement object are measured in the vicinity. The temperature / thickness measuring apparatus according to claim 9. The optical path lengths of the plurality of reference beams from the reference beam splitter are measured so that all or part of the peak widths of the interference waveforms of the measurement beam and the reference beam for each measurement object overlap each other. The temperature / thickness measuring apparatus according to claim 10, which is adjusted. 2. The temperature / thickness measuring apparatus according to claim 1, wherein the reference light transmission means includes a bypass optical path connected in parallel to the optical path of the reference light in the middle of the optical path of the reference light. The optical path length of the detour optical path of the reference light is adjusted so that an interference waveform between the measurement light and the reference light for each measurement object is measured in the vicinity. Temperature / thickness measuring device. The optical path length of the detour optical path of the reference light is adjusted such that all or part of the peak widths of the interference waveform between the measurement light and the reference light for each measurement object overlap each other and are measured. The temperature / thickness measuring apparatus according to claim 13. The temperature / thickness measuring apparatus according to claim 1, wherein each of the lights is transmitted through the air. Each measurement object is formed of silicon or a silicon oxide film,
The temperature / thickness measuring apparatus according to claim 1, wherein the light source is capable of emitting light having a wavelength of 1.0 to 2.5 μm. 17. The temperature / thickness measurement according to claim 16, wherein the measurement object is a substrate to be processed in a substrate processing apparatus and an electrode plate disposed to face the substrate to be processed. apparatus. 17. The measurement object is a peripheral ring disposed around a substrate to be processed in a substrate processing apparatus and an electrode plate disposed to face the peripheral ring. The temperature / thickness measuring apparatus according to 1. A temperature / thickness measurement method for measuring the temperature or thickness of a plurality of measurement objects arranged opposite to each other based on light interference,
The split measurement light from a light source that emits light having a wavelength that passes through and reflects each measurement object is irradiated toward the plurality of measurement objects so as to pass through each measurement object, and the reference light Irradiating to the reference light reflecting means,
While changing the optical path length of the reference light reflected from the reference light reflecting means by scanning the reference light reflecting means in one direction, the measuring light reflected from each measurement object and the reference light reflecting means Measuring the interference of light with the reflected reference light;
Measuring the temperature or thickness of each measurement object based on the result of the interference measurement;
A temperature / thickness measuring method characterized by comprising: In the middle of the optical path of the measurement light, a bypass optical path connected in parallel with the optical path of the measurement light is provided,
The step of measuring the interference includes the interference of the measurement light transmitted without passing through the detour optical path of the measurement light and the reference light, and the measurement transmitted at least once through the detour optical path of the measurement light. 20. The temperature / thickness measuring method according to claim 19, wherein light interference between the light and the reference light is measured. A measuring light splitter for splitting the measuring light split from the light source into a plurality of measuring lights;
The step of measuring the interference measures the interference of light between each measurement light reflected from each measurement object by the plurality of measurement lights from the measurement light splitter and the reference light reflected from the reference light reflecting means. The temperature / thickness measuring method according to claim 19, wherein: The reference light reflecting means is provided with a plurality of reflecting surfaces,
The step of measuring the interference measures light interference between a plurality of reference lights reflected from the respective reflecting surfaces and a reference light split from the light source and the respective measuring lights reflected from the respective measuring objects. The temperature / thickness measuring method according to claim 19. A reference light splitter for further splitting the reference light from the splitter into a plurality of reference lights;
The step of measuring the interference includes the interference of light between each reference light reflected from the reference light reflecting means by a plurality of reference lights from the reference light splitter and each measurement light reflected from each measurement object. The temperature / thickness measurement method according to claim 19, wherein the temperature / thickness measurement method is performed. In the middle of the optical path of the reference light, a bypass optical path connected in parallel with the optical path of the reference light is provided,
The step of measuring the interference includes interference of light between the reference light and the measurement light transmitted without passing through the detour optical path of the reference light, and a reference transmitted at least once through the detour optical path of the reference light. 20. The temperature / thickness measurement method according to claim 19, wherein light interference between the light and the measurement light is measured. 25. The temperature / thickness measuring method according to claim 19, wherein each of the lights is transmitted through the air. Each measurement object is formed of silicon or a silicon oxide film,
The temperature / thickness measurement method according to any one of claims 19 to 25, wherein the light source is capable of emitting light having a wavelength of 1.0 to 2.5 µm. 27. The temperature / thickness according to claim 26, wherein each measurement object is a substrate to be processed in a substrate processing apparatus and an electrode plate disposed to face the substrate to be processed. Measuring method. 27. The measurement object is a peripheral ring disposed around a substrate to be processed in a substrate processing apparatus and an electrode plate disposed opposite to the peripheral ring. 4. The temperature / thickness measuring method described in 1. 29. The temperature / thickness measurement method according to claim 19, wherein the light intensity of the light source is changed during measurement of light interference between the measurement light and the reference light. 30. The temperature / thickness measurement method according to claim 29, wherein the light intensity of the light source is gradually increased in accordance with a moving distance of the reference light reflecting means. 30. The temperature / thickness measurement method according to claim 29, wherein the light intensity of the light source is changed for each measurement object. 32. The temperature / thickness measurement method according to claim 31, wherein the light intensity of the light source is changed according to the reflection intensity of the measurement light from each measurement object. 32. The temperature / thickness measurement method according to claim 31, wherein the light intensity of the light source is increased as the measurement object is farther from the irradiation position of the measurement light. By applying high frequency power to an electrode plate disposed in the processing chamber, a substrate processing apparatus for performing a predetermined process on a substrate to be processed disposed opposite to the electrode plate, and a temperature / temperature attached to the substrate processing apparatus A temperature / thickness measurement system comprising a thickness measurement device and a controller for controlling the temperature / thickness measurement device,
The temperature / thickness measurement apparatus irradiates light having a wavelength that transmits and reflects at least each measurement object including at least the electrode plate and the substrate to be processed or a peripheral ring disposed around the substrate to be processed. A light source, a splitter for splitting light from the light source into measurement light and reference light, reference light reflecting means for reflecting the reference light from the splitter, and reference light reflected from the reference light reflecting means An optical path length changing means for changing the optical path length of the light source, a reference light transmitting means for transmitting the reference light from the splitter to the reference light irradiating position for irradiating the reference light to the reference light reflecting means, and a measuring light from the splitter Measuring light transmission means for transmitting the measurement light to the measurement object so as to pass through the measurement object to the measurement light irradiation position, each measurement light reflected from the measurement object, And a light receiving means for measuring the interference light between the reference beam reflected from the serial reference light reflecting means,
The temperature / thickness measurement system, wherein the control device obtains the temperature or thickness of each measurement object based on the result of interference measurement from the light receiving means. A substrate processing apparatus for applying a predetermined process to a substrate to be processed disposed opposite to the electrode plate by applying high-frequency power to an electrode plate disposed in the processing chamber, and a temperature installed in the substrate processing apparatus A control system comprising: a thickness measuring device; and a control device for controlling the temperature / thickness measuring device and the substrate processing device,
The temperature / thickness measurement apparatus irradiates light having a wavelength that transmits and reflects at least each measurement object including at least the electrode plate and the substrate to be processed or a peripheral ring disposed around the substrate to be processed. A light source, a splitter for splitting light from the light source into measurement light and reference light, reference light reflecting means for reflecting the reference light from the splitter, and reference light reflected from the reference light reflecting means An optical path length changing means for changing the optical path length of the light source, a reference light transmitting means for transmitting the reference light from the splitter to the reference light irradiating position for irradiating the reference light to the reference light reflecting means, and a measuring light from the splitter Measuring light transmission means for transmitting the measurement light to the measurement object so as to pass through the measurement object to the measurement light irradiation position, each measurement light reflected from the measurement object, Light receiving means for measuring the interference light between the reference beam reflected from the serial reference light reflecting means,
The control device obtains the temperature or thickness of each measurement object based on the result of interference measurement from the light receiving means, and based on the temperature or thickness, the control device is in the processing chamber of the substrate processing apparatus. A control system that performs at least one of temperature control and process control of a substrate to be processed. A control method for a control system of a substrate processing apparatus for applying a predetermined process to a substrate to be processed disposed opposite to an electrode plate by applying high frequency power to an electrode plate disposed in a processing chamber,
Measurement light split from a light source that emits light having a wavelength that passes through and reflects a plurality of measurement objects including at least the electrode plate and the substrate to be processed or a peripheral ring disposed around the substrate to be processed. Irradiating the plurality of measurement objects so as to pass through each of the measurement objects, and irradiating the reference light toward the reference light reflecting means;
While changing the optical path length of the reference light reflected from the reference light reflecting means by scanning the reference light reflecting means in one direction, the measuring light reflected from each measurement object and the reference light reflecting means Measuring the interference of light with the reflected reference light;
Measuring the temperature or thickness of each measurement object based on the result of the interference measurement;
Performing at least one of temperature control and process control of the substrate to be processed in the substrate processing apparatus based on the measured temperature or thickness of each measurement object;
A control method comprising:

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