JP5319856B1 - Film thickness measuring apparatus and film forming apparatus - Google Patents

Abstract

A film thickness measuring apparatus capable of measuring an optical film thickness with high accuracy is provided.
A light projector 11 that irradiates light toward the monitor substrate Sm through the irradiation side fiber f1, a light receiving device 22 that receives light reflected from the monitor substrate Sm after being irradiated from the light projector 11 through the light reception side fiber f2, and a plurality of light receiving devices 22 In the film thickness measuring device 6 including the optical sensor probe 13 formed by bundling the irradiation side fiber f1 and the plurality of light receiving side fibers f2, the tip surface of the optical sensor probe 13 facing the monitor substrate Sm is provided. A plurality of end faces of the irradiation side fiber f1 and a plurality of end faces of the light receiving side fiber f2 are disposed, and each of the end faces of the irradiation side fiber f1 is adjacent to the end face of the light receiving side fiber f2. And each end face of the light receiving side fiber f2 is adjacent to each end face of the irradiation side fiber f1 in an arc shape or an annular shape. It is arranged.

Description

  The present invention relates to a film thickness measuring apparatus and a film forming apparatus equipped with the film thickness measuring apparatus, and more particularly to an optical film formed on a substrate to be measured through an optical fiber in order to measure an optical film thickness formed on the substrate to be measured. The present invention relates to a film thickness measuring apparatus that irradiates light and receives reflected light reflected by a measurement substrate through an optical fiber, and a film forming apparatus equipped with the film thickness measuring apparatus.

  Forming an optical thin film with high precision so as to have a predetermined thickness is desired in each field using the optical thin film. On the other hand, accurate film thickness measurement is indispensable for highly accurate film thickness control of an optical thin film. The film thickness referred to here is an optical film thickness, and is a value determined by the physical film thickness and the refractive index of the thin film.

  As a method for measuring the film thickness, a phenomenon in which a light beam reflected on the surface of the optical thin film and a light beam reflected on the interface between the substrate and the optical thin film interfere with each other by causing a phase difference due to a path difference is used. A reflection measurement method for measuring a film thickness is known, and various apparatuses have been proposed for a film thickness measurement apparatus employing such a measurement method.

  As an example of a conventional film thickness measuring apparatus, there is a film thickness measuring apparatus mounted on the film forming apparatus described in Patent Document 1. In such an apparatus, light projected on the optical thin film is propagated from the light source through the optical fiber, and light reflected at the interface between the substrate and the optical thin film is propagated to the spectroscope through the optical fiber.

  When the film thickness measurement device is installed in the vacuum film formation device, the monitor glass is set in the device together with the substrate that will eventually become a multilayer film product, and the thin film is also applied to the monitor glass under the same conditions as the substrate. Form. Then, during the film forming process, the film thickness is monitored by measuring the optical film thickness of the thin film formed on the monitor glass side. Thereby, the optical film thickness of each layer of the multilayer film formed on the substrate side can be measured. In the conventional vacuum film-forming apparatus, the monitor glass changes from a glass that has already been formed to a new glass, that is, a monitor glass before film formation, each time a multilayer film is formed on the substrate during the film-forming process. Will be replaced.

Japanese Patent No. 3866933

By the way, in the reflection type film thickness measurement, when the light beam is incident on the optical thin film of the substrate at an angle, the film thickness is measured when the light beam is irradiated perpendicularly to the optical thin film. Thickness, that is, it becomes thinner than the original film thickness. More specifically, assuming that the incident angle of the light beam with respect to the optical film of the substrate is θ, the refractive index of the optical film is n, and the original film thickness is d0, the measured value d of the film thickness is given by the following formula (1 ).
d = (d0 / n ² ) × √ {n ² − (sin θ) ² } (1)
Therefore, as the incident angle θ increases, the film thickness measurement error Δd (= d0−d) increases and the film thickness measurement accuracy decreases.

  As shown in FIG. 9, the incident angle θ corresponds to half of the angle formed by the optical path of light incident on the substrate and the optical path of light reflected on the substrate side. FIG. 9 is an explanatory diagram relating to the incident angle.

  Considering the relationship between the incident angle θ and the measurement error Δd of the film thickness, the area (effective light projection range) of the portion that actually irradiates light in the projector that irradiates the optical thin film is minimized, It is desirable to reduce the incident angle θ.

  In addition, for the purpose of irradiating light to a predetermined position of the optical thin film with high accuracy, a condensing lens may be provided between the projector and the optical thin film, and the optical thin film may be irradiated with light through the condensing lens. Similarly, for the purpose of accurately receiving the reflected light reflected from the optical thin film, a light receiving lens may be provided between the light receiver and the optical thin film, and the reflected light from the optical thin film may be received via the light receiving lens. is there. In such a case, the illuminance is attenuated as light passes through the lens, which may affect the measurement accuracy of the film thickness.

  Furthermore, if the monitor glass is replaced each time a layer is formed on the substrate on which the multilayer film is formed, variations will occur between the monitor glasses in terms of size, surface condition, and processing accuracy, and this variation will affect thin film measurement accuracy. There is a risk of affecting.

  If the optical film thickness is not accurately measured for the reasons described above, the accuracy of the film thickness control performed reflecting the measurement result also decreases, and a thin film having a desired film thickness is obtained. It will be difficult to get.

  Accordingly, an object of the present invention is to provide a film thickness measuring apparatus capable of measuring an optical film thickness with high accuracy. In addition, another object of the present invention is to provide a film forming apparatus capable of accurately controlling the film thickness of a thin film formed on a substrate based on an accurate measurement result of an optical film thickness. .

According to the film thickness measuring apparatus of the present invention, the subject is directed toward the substrate to be measured through an irradiation side fiber made of an optical fiber in order to measure the optical film thickness of the film formed on the substrate to be measured. An irradiating device that irradiates light, and a light receiving device that receives the light reflected from the substrate to be measured after being irradiated from the irradiating device through a light receiving side fiber including an optical fiber in order to measure the optical film thickness. An apparatus, and a probe formed by bundling a plurality of the irradiation side fibers and a plurality of the light receiving side fibers, and a surface provided on a side of the probe facing the substrate to be measured as an end surface, A plurality of end faces of the irradiation side fibers and a plurality of end faces of the light receiving side fibers are arranged, and each of the end faces of the plurality of irradiation side fibers arranged on the facing surface is at least Each of the end faces of the plurality of light receiving side fibers arranged in an arc shape or an annular shape adjacent to the end face of the one light receiving side fiber is arranged on the end face of at least one of the irradiation side fibers. A row of end faces of the irradiation side fibers arranged in an arc shape or an annular shape adjacent to each other , and an end face of the light receiving side fibers arranged in an arc shape or an annular shape are arranged. The rows formed are alternately arranged at least three times from an arbitrary point on the outer periphery of the facing surface toward the inside of the facing surface, and the probe includes the facing surface and the substrate to be measured. In the state where no optical component is provided between the substrate for measurement and the non-film-formation surface located on the opposite side of the measurement substrate from the side on which the film is formed. Being It is more resolved.

  In the above thin film measuring apparatus, if the end face of the irradiation side fiber and the end face of the light receiving side fiber are adjacent to each other on the facing surface provided on the side facing the substrate to be measured as the end face, the irradiation apparatus changes the thin film to the thin film. On the other hand, the incident angle of the irradiated light becomes smaller.

More specifically, an optical path when the light irradiated from the end face of the irradiation side fiber goes to the thin film and an optical path when the light is reflected by the substrate to be measured and goes to the end face of the light receiving side fiber are: The angle formed when the end face of the irradiation side fiber and the end face of the light receiving side fiber are adjacent to each other is smaller than when the end faces of both fibers are not adjacent to each other. On the other hand, since the incident angle is ½ of the size of the angle formed by the two optical paths, when the end face of the irradiation side fiber and the end face of the light receiving side fiber are adjacent to each other, the incident angle also depends on the incident angle. Get smaller. When the incident angle is thus reduced, the measurement error Δd is reduced by the relationship between the incident angle and the film thickness measurement error Δd (specifically, the above-described equation (1)).
Further, if the end face of the irradiation side fiber and the end face of the light receiving side fiber are adjacent to each other, the reflected light can be efficiently received through the light receiving side fiber.

Furthermore, since the accuracy of the film thickness measurement increases as the filling rate of the fiber at the end face of the probe increases, the end faces of the fibers are usually arranged in a dense state within the end face of the probe. On the other hand, as the end faces of the fibers are denser, the end faces of the irradiation side fibers and the end faces of the light receiving side fibers are more likely to be densely packed. On the other hand, if each fiber is arranged so that the end face of the irradiation side fiber and the end face of the light receiving side fiber are arranged in an arc shape or an annular shape on the end face of the probe, the irradiation side fiber and the light receiving side fiber are adjacent to each other. A suitable fiber arrangement can be realized efficiently.
Due to the above-described action, the film thickness measuring apparatus according to claim 1 can measure the optical film thickness more accurately than the conventional apparatus.

In the configuration of the following, it is not used a condenser lens and the light receiving lens, become light loss can be suppressed, when receiving the reflected light through the light-receiving side fiber, receives the reflected light at a relatively large illumination It becomes possible to do. As the amount of light received through the light receiving side fiber increases, the S / N ratio when the light is subjected to spectral analysis to calculate the film thickness is improved. Therefore, the configuration according to claim 1 makes it possible to measure the optical film thickness with higher accuracy.

Further, in the above thin film measuring apparatus, the plurality of irradiation side fibers and the plurality of light receiving side fibers constituting the probe constitute a bundle fiber whose end faces are aligned on the facing surface, and the facing surface and the component are formed. It is more preferable that the distance to the film surface is at least twice the diameter of the bundle fiber.
In the above configuration, the incident angle of light with respect to the thin film, in other words, the reflection angle of the light reflected by the thin film is equal to or less than the numerical aperture NA of the light receiving side fiber. In this case, the light receiving efficiency when receiving light through the light receiving side fiber is further increased. Therefore, according to the configuration of the second aspect , the optical film thickness can be measured with higher accuracy.

In the thin film measuring apparatus, the substrate for measurement may be a disk-shaped or annular substrate. That is, in the configuration described in claim 3 , it is possible to accurately measure the optical film thickness of the thin film formed on the disk-shaped or annular substrate for measurement. Furthermore, in a film thickness measuring apparatus that can monitor the film thickness at multiple points, if a disk-shaped or annular substrate is used, the number of monitor points can be increased as compared with, for example, a rectangular substrate.

The thin film measuring apparatus may further include the irradiation device, a DC stabilized power source that supplies a direct current to a light source provided in the irradiation device, the probe, and the light receiving device, and the light receiving device includes the light receiving device. A spectrometer that outputs an analog signal corresponding to the intensity of light received when the light reflected by the measurement substrate is received, an amplifier that amplifies the analog signal output from the spectrometer, and the amplifier that is amplified by the amplifier An A / D converter that converts the analog signal into a digital signal; an electronic calculator that calculates the optical film thickness based on the digital signal; and the A / D converter and the electronic calculator, The electric calculator may include a signal processing circuit for performing predetermined signal processing on the digital signal when calculating the optical film thickness. That is, in the configuration according to the fourth aspect , it is possible to accurately measure the optical film thickness of the thin film after having the same equipment as the constituent equipment of the normal thin film measuring apparatus.

In addition, the above-described problem is a film forming apparatus for forming a film on a substrate by depositing a vapor deposition material on the surface of the substrate in a vacuum vessel in the film forming apparatus of the present invention. An evaporation mechanism for evaporating, an opening / closing member that opens and closes to block a path when the vapor deposition material evaporated by the evaporation mechanism goes to the surface of the substrate, and a control mechanism that controls opening and closing of the opening / closing member And the film thickness measuring device according to any one of claims 1 to 4 , wherein both the substrate and the substrate to be measured are accommodated in the vacuum vessel, The evaporation mechanism evaporates the vapor deposition material, the film thickness measuring device measures the optical film thickness of the film formed on the substrate to be measured, and the control mechanism includes: Of the optical film thickness by the film thickness measuring device. It is solved by controlling the opening and closing of the closing member according to a constant result.
Since the film forming apparatus configured as described above includes the film thickness measuring apparatus that achieves the above-described effects, it is possible to accurately measure the film thickness, and further, according to the measurement result, the film thickness can be measured. Control will be performed. Therefore, if it is the film-forming apparatus of Claim 5 , it will become possible to control the film thickness of the thin film formed in a board | substrate accurately with the accurate measurement result of an optical film thickness.

Further, in the film forming apparatus, while the multilayer film is formed on the substrate, the same substrate for measurement is disposed in the vacuum vessel to form the multilayer film on the substrate for measurement. It is more preferable that the film thickness measuring device measures the optical film thickness of each layer of the multilayer film formed on the substrate to be measured for each layer.
With the above configuration, the optical film thickness of each layer film is measured each time each layer of the multilayer film is formed on the substrate to be measured without changing the substrate to be measured while the multilayer film is formed on the substrate. Therefore, it is possible to suppress the influence caused by the change of the substrate to be measured every time the film thickness of each layer is measured. Therefore, if it is the film-forming apparatus of Claim 6 , it is possible to measure the film thickness of each layer of the multilayer film formed on the substrate with high accuracy, and to perform the film thickness control more accurately based on the measurement result. It becomes.

In the film thickness measuring apparatus according to the first aspect, it is possible to measure the optical film thickness more accurately than in the conventional apparatus. Further, a film thickness measuring device according to claim 1, the partial to improve the S / N ratio of the spectral analysis allows to measure more accurately the optical thickness.
In the film thickness measuring apparatus according to the second aspect , since the reflection angle of the light reflected by the thin film is less than or equal to the numerical aperture NA of the light receiving side fiber, the optical film thickness can be measured with higher accuracy.
In the film thickness measuring apparatus according to the third aspect , it is possible to accurately measure the optical film thickness of the thin film formed on the disk-shaped or annular substrate for measurement. Further, in a film thickness measuring apparatus capable of multipoint monitoring of film thickness, if a disk-shaped or annular substrate is used, the number of monitor points can be increased as compared with a rectangular substrate.
In the film thickness measuring apparatus according to the fourth aspect , it is possible to accurately measure the optical film thickness of the thin film after having the same equipment as the constituent equipment of the normal thin film measuring apparatus.
In the film forming apparatus according to the fifth aspect , the film thickness can be accurately measured, and the film thickness can be accurately controlled according to the measurement result.
In the film forming apparatus according to claim 6 , when measuring the optical film thickness of each layer of the multilayer film formed on the substrate, it is formed on the substrate as much as the influence caused by changing the substrate to be measured for each layer can be suppressed. It is possible to accurately measure the film thickness of each layer of the multilayer film, and to control the film thickness more accurately based on the measurement result.

It is a figure which shows schematic structure of the film-forming apparatus which concerns on this embodiment. It is a model side view of the probe which concerns on this embodiment. FIGS. 3A and 3B are diagrams illustrating fiber arrangement positions in the first example. It is a figure which shows the arrangement position of the fiber in a comparative example. FIGS. 5A and 5B are diagrams showing the arrangement positions of the fibers in the second example. It is explanatory drawing about the effectiveness of the arrangement position of the fiber which concerns on this embodiment. (A) and (B) of Drawing 7 are figures showing other variations about the 2nd example. FIGS. 8A and 8B are views showing the arrangement positions of the fibers in the third example. It is explanatory drawing regarding an incident angle.

Hereinafter, embodiments of the present invention (hereinafter referred to as “this embodiment”) will be described with reference to the drawings.
First, a schematic configuration of a film forming configuration according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of a film forming apparatus according to this embodiment.

  The film forming apparatus according to the present embodiment is an apparatus that forms a multilayer film on a substrate by depositing a deposition material on the surface of the substrate in a vacuum vessel, and in particular, a vacuum deposition apparatus that forms a film by a vacuum deposition method. 100. Further, in the vacuum deposition apparatus 100 of the present embodiment, a thin film optical film formed on the monitor substrate Sm side by setting a substrate (hereinafter referred to as an actual substrate S) and a monitor substrate Sm for film thickness measurement in the vacuum vessel 1. While measuring the thickness, the film thickness of the thin film formed on the actual substrate S side can be controlled based on the measurement result.

  Here, the actual substrate S is a substrate that is actually attached to the thin-film device, and is made of, for example, glass. On the other hand, the monitor substrate Sm corresponds to a substrate to be measured and is used only for film thickness monitoring, and is made of the same material as the actual substrate S, for example, glass. In particular, the monitor substrate Sm according to the present embodiment is an annular substrate in plan view, and a suitable thickness is 1.0 to 2.0 mm.

  In this embodiment, a multilayer film is formed on the monitor substrate Sm under the same conditions as the actual substrate S. That is, in this embodiment, the optical film thickness of the thin film formed on the actual substrate S side and the optical film thickness of the thin film formed on the monitor substrate Sm side are regarded as the same, and the optical film thickness of the thin film on the monitor substrate Sm side. To monitor the optical film thickness of the thin film on the actual substrate S side.

  The configuration of the vacuum deposition apparatus 100 will be described. As shown in FIG. 1, the vacuum vessel 1, the substrate holder 2, the evaporation mechanism 3, the shutter 4, the shutter control unit 5, and the film thickness measuring device 6 are mainly used. It is provided as a component.

  A dome-shaped substrate holder 2 is accommodated in an upper space of the inner space of the vacuum vessel 1, and a plurality of actual substrates S are attached to the inner surface of the substrate holder 2. In addition, an opening 2a is formed at the center position of the inner surface of the substrate holder 2, and one monitor substrate Sm is disposed immediately below the opening 2a. A part of the monitor substrate Sm arranged at this position is exposed to the outside of the dome through the opening 2a.

  Further, the substrate holder 2 rotates around the rotation axis along the vertical direction during the film formation period in order to make the film formation amount between the actual substrates S uniform. During this time, the monitor substrate Sm rotates relative to the substrate holder 2. That is, in the present embodiment, the monitor substrate Sm is held by a monitor substrate holder (not shown) that is separate from the substrate holder 2, and the substrate holder 2 and the monitor substrate holder can rotate independently of each other. It is.

  On the other hand, an evaporation mechanism 3 is provided in a lower space of the inner space of the vacuum vessel 1. The evaporation mechanism 3 is for evaporating a deposition material to be deposited on the actual substrate S or the monitor substrate Sm for forming a thin film. More specifically, the evaporation mechanism 3 according to the present embodiment is the same type as the evaporation mechanism that is normally provided in a vacuum evaporation apparatus. For example, an evaporation material held in a crucible (not shown) is heated by an electron beam. An electron beam device that evaporates may be used.

  A shutter 4 is provided between the substrate holder 2 and the evaporation mechanism 3. The shutter 4 is an example of an opening / closing member, and is opened / closed by a driving mechanism (not shown) in order to block a path when the vapor deposition material evaporated by the evaporation mechanism 3 goes to the surface of the actual substrate S or the monitor substrate Sm. To do. More specifically, when the shutter 4 is in the open position (the position of the shutter 4 indicated by a solid line in FIG. 1), the vapor deposition material evaporated by the evaporation mechanism 3 is scattered and the actual substrate S or the monitor. It can be supplied to the substrate Sm. On the other hand, when the shutter 4 is in the closed position (the position of the shutter 4 indicated by a broken line in FIG. 1), the deposition of the vapor deposition material is prevented by the shutter 4, and as a result, vapor deposition on the actual substrate S and the monitor substrate Sm. The material supply becomes impossible.

  The shutter control unit 5 corresponds to a control mechanism for controlling the opening and closing of the shutter 4 and is configured by a second computer PC2 described later in this embodiment. More specifically, the second computer PC2 is connected to the shutter 4 via an interface (not shown), and the control program installed in the second computer PC2 is executed to control the shutter 4 toward the shutter 4. Output a signal. When the shutter 4 receives a control signal from the second computer PC2, the shutter 4 opens and closes according to the control signal.

  The film thickness measuring apparatus 6 is an apparatus for measuring the optical film thickness of the thin film formed on the monitor substrate Sm. In particular, in the present embodiment, the film thickness measuring apparatus 6 measures the film thickness by a reflection method. That is, the film thickness measuring apparatus 6 according to the present embodiment makes light incident on the thin film formed on the monitor substrate Sm, receives the light reflected by the monitor substrate Sm, and then splits the reflected light. The light intensity (spectrum) for each wavelength is detected. Then, the optical film thickness of the thin film formed on the monitor substrate Sm is calculated based on the detected light intensity.

  Furthermore, the film thickness measuring device 6 according to the present embodiment measures the optical film thickness of each layer in the multilayer film formed on the monitor substrate Sm for each layer. More specifically, as described above, the monitor substrate Sm rotates independently of the substrate holder 2, while a monitor substrate mask (not shown) is disposed immediately below the monitor substrate Sm. . This monitor substrate mask is a disk-shaped member, and an opening is formed at the center thereof. A part of the monitor substrate Sm is exposed to the evaporation mechanism 3 through this opening.

  On the other hand, in a state where both the actual substrate S and the monitor substrate Sm are accommodated in the vacuum vessel 1, the evaporation mechanism 3 evaporates the vapor deposition material in order to deposit the vapor deposition material on both surfaces. As a result, a thin film is formed under substantially the same conditions on the film formation surfaces of the actual substrate S and the monitor substrate Sm. At this time, in the film formation surface of the monitor substrate Sm, the region where the thin film is formed is only the region exposed through the opening formed in the monitor substrate mask.

  Further, as described above, in this embodiment, a multilayer film is formed on the actual substrate S, and each time a thin film of each layer is formed, the vapor deposition material and the film forming conditions form the thin film of the next layer. To the materials and conditions to do. On the other hand, a multilayer film is also formed on the monitor substrate Sm under substantially the same conditions as the substrate. However, in this embodiment, the monitor is switched when the vapor deposition material and film formation conditions are switched after a thin film for one layer is completed. The substrate Sm rotates relative to the stationary monitor substrate mask by a predetermined rotation angle. As the monitor substrate Sm rotates relative to the monitor substrate mask in this way, the region exposed through the opening formed in the monitor substrate mask in the monitor substrate Sm is shifted by the rotation angle. As a result, the region where the thin film is formed is shifted by the rotation angle.

  In the subsequent film formation process, an area of the monitor substrate Sm exposed before the rotation (hereinafter referred to as an exposure area before the rotation) and an area exposed after the rotation (hereinafter referred to as the exposure after the rotation). A thin film of a new layer is formed in the overlapping area with the region. On the other hand, the thin film of a new layer is not formed in the range which does not overlap with the exposed area after rotation among the exposed areas before rotation. Therefore, the film thickness of the thin film formed by each film forming process is the area exposed in the monitor substrate Sm before and after the rotation operation immediately before the film forming process is performed and after the rotation operation. It is calculated | required by comparing the optical film thickness of the thin film currently formed with the area | region which disappears.

  Next, the configuration of the film thickness measuring device 6 according to the present embodiment will be described with reference to FIGS. FIG. 2 is a schematic side view of the probe according to the present embodiment.

  As shown in FIG. 1, the film thickness measuring device 6 includes a projector 11, a DC stabilized power supply 12, an optical sensor probe 13, a spectrometer 14, an amplifier 15, an A / D converter 16, a signal A processing circuit 17 and two computers PC1 and PC2 are included as main components.

  The projector 11 is an example of an irradiation device, and irradiates light toward the monitor substrate Sm through the irradiation side fiber f1 made of an optical fiber in order to measure the optical film thickness of the film formed on the monitor substrate Sm. More specifically, the projector 11 includes a light source 21 including a halogen lamp, and irradiates white light emitted from the light source 21 from the tip surface of the optical sensor probe 13 on which the end surface of the irradiation side fiber f1 is disposed. To do. Here, the light projector 11 is synchronized with the spectroscope 14, and the light source 21 is repeatedly turned off and on in synchronization with the output period of the incident light intensity in the spectroscope 14. A direct current is supplied from the direct current stabilized power supply 12 to the light source 21 provided in the projector 11.

  The spectroscope 14 includes a light receiving device 22 and outputs an analog signal corresponding to the received light intensity when the light receiving device 22 receives light reflected by the monitor substrate Sm. More specifically, the light receiving device 22 provided in the spectroscope 14 is constituted by, for example, a CCD (Charge Coupled Device), and the monitor substrate after being irradiated from the projector 11 in order to measure the optical film thickness. The light reflected by Sm is received through a light receiving side fiber f2 made of an optical fiber. The spectroscope 14 divides the light received by the light receiving device 22, detects the light intensity (spectrum) for each wavelength, and outputs an electrical signal corresponding to the detection result. Here, the electrical signal output from the spectroscope 14 corresponds to an analog signal corresponding to the received light intensity when the light receiving device 22 receives the reflected light.

  The spectroscope 14 also splits the light emitted from the projector 11 and outputs an optical signal indicating the light intensity of each wavelength of the incident light, that is, the incident light intensity. As described above, the spectroscope 14 outputs an electric signal indicating the incident light intensity and an electric signal indicating the reflected light intensity. The two types of electrical signals output from the spectroscope 14 are each amplified by an amplifier 15 and then converted into a digital signal by an A / D converter 16. Thereafter, the digital signal is input to the second computer 19.

  The optical sensor probe 13 is an example of a probe, and is formed by bundling a plurality of irradiation side fibers f1 and a plurality of light receiving side fibers f2. More specifically, the plurality of irradiation side fibers f1 connected to the projector 11 and the plurality of light receiving side fibers f2 connected to the light receiving device 22 form bundles as shown in FIG. It is housed in the flexible tube 23.

  The irradiation side fiber f1 and the light receiving side fiber f2 each have a core and a coating covering the core. In this embodiment, the core diameter is about 200 μm, and the fiber diameter including the coating is about 235 μm. ing.

  In addition, a connection connector 24A is attached to the end of the bundle formed by the irradiation side fiber f1 on the side connected to the projector 11. Similarly, the connection connector 24B is attached to the end of the bundle formed by the light receiving side fiber f2 on the side connected to the light receiving device 22.

  The bundled irradiation side fiber f1 and light receiving side fiber f2 are bundled together on the free end side to form an optical sensor probe 13. That is, the plurality of irradiation side fibers f1 and the plurality of light receiving side fibers f2 constituting the optical sensor probe 13 form a bundle fiber whose end surfaces are aligned on the free end side surface of the optical sensor probe 13.

  More specifically, as shown in FIG. 2, the bundles of the fibers f <b> 1 and f <b> 2 merge at the intermediate connector 24 </ b> C, are combined into one bundle, and are accommodated in the same flexible tube 23. Furthermore, a cylindrical protective cylinder 25 is attached to the end portion on the free end of the irradiation side fiber f1 and the light receiving side fiber f2 in a state of being bundled as one bundle. The fibers f1 and f2 housed inside are disposed in the vacuum vessel 1.

  The protective cylinder 25 includes a large-diameter portion 25 a and a small-diameter portion 25 b having different diameters, and the small-diameter portion 25 b forms the tip of the optical sensor probe 13. The optical sensor probe 13 is set so that one end surface of the small-diameter portion 25b, which is the tip surface thereof, faces the monitor substrate Sm at a position directly above the monitor substrate Sm. That is, one end surface of the small diameter portion 25b that forms the tip surface of the optical sensor probe 13 corresponds to a facing surface provided on the side where the optical sensor probe 13 faces the monitor substrate Sm.

  In the small diameter portion 25b, the end surfaces are aligned so that the irradiation side fiber f1 and the light receiving side fiber f2 are flush with each other. Therefore, a plurality of end faces of the irradiation side fiber f1 and a plurality of end faces of the light receiving side fiber f2 are arranged on one end face of the small diameter portion 25b. Here, in this embodiment, the end face of the irradiation side fiber f1 and the end face of the light receiving side fiber f2 are regularly arranged on one end face of the small diameter portion 25b. The arrangement position of the fibers f1 and f2 on the one end face of the small diameter portion 25b will be described in detail later.

  As described above, the optical sensor probe 13 of the present embodiment is configured by a bundle fiber in which a plurality of irradiation side fibers f1 and light receiving side fibers f2 are bundled. In the present embodiment, the number of each of the irradiation side fibers f1 and the light receiving side fibers f2 constituting the optical sensor probe 13 is 20 or more. Thereby, the film thickness measuring apparatus 6 according to the present embodiment enables multipoint monitoring of the film thickness.

  The two computers PC1 and PC2 can communicate with each other via Ethernet (registered trademark), and the first computer PC1 which is one computer controls the projector 11. In the present embodiment, the first computer PC1 controls the light irradiation operation of the projector 11 via the programmable logic controller PLC for communication protocol conversion. The second computer PC2, which is the other computer, is an example of an electronic computer. Based on the digital signal generated by the A / D converter 16 converting the electrical signal output from the spectroscope 14, the monitor board is used. The optical film thickness of the thin film formed on Sm is calculated.

  A signal processing circuit 17 is interposed between the A / D converter 16 and the second computer PC2. The signal processing circuit 17 performs predetermined signal processing on the digital signal when the second computer PC2 calculates the optical film thickness. Here, the predetermined signal processing is processing for converting the above digital signal into a signal in a format suitable for use in the optical film thickness calculation by the second computer PC2, for example, removing components other than the interference signal Such as wavelet processing and frequency analysis processing.

  Furthermore, as described above, the second computer PC2 corresponds to a control mechanism that controls the opening and closing of the shutter 4, and controls the opening and closing of the shutter 4 according to the calculated value of the optical film thickness. Here, the calculated value of the optical film thickness calculated by the second computer PC2 is the measurement result of the optical film thickness by the film thickness measuring device 6.

  The configuration of the film thickness measuring device 6 according to the present embodiment described above is mostly the same as the configuration of the conventional reflective film thickness measuring device, but there are four points described below. This is different from the conventional apparatus.

  The first difference is that optical components such as a condensing lens and a light receiving lens are not provided between the tip surface of the optical sensor probe 13 and the monitor substrate Sm. That is, in this embodiment, as shown in FIG. 1, the optical sensor probe 13 is in a state in which no optical component is provided between one end surface of the small-diameter portion 25b forming the tip surface and the monitor substrate Sm. One end surface of the small diameter portion 25b faces the non-film-forming surface of the monitor substrate Sm. Here, the non-deposition surface is a surface located on the opposite side of the monitor substrate Sm from the side on which the film is formed.

  As described above, since no optical component is provided between the tip surface of the optical sensor probe 13 and the monitor substrate Sm, in the present embodiment, it is possible to suppress light loss caused by passing through the optical component. As a result, the light receiving side fiber f2 can receive the reflected light with a relatively large illuminance. The S / N ratio at the time of performing spectral analysis of the light in order to calculate the film thickness is increased by the amount of light received by the light receiving side fiber f2. Therefore, the film thickness measuring device 6 according to the present embodiment can accurately measure the optical film thickness.

  When no optical component is provided between the tip surface of the optical sensor probe 13 and the monitor substrate Sm, the bundle fiber formed by the irradiation side fiber f1 and the light receiving side fiber f2 is used for the diameter of the effective projection spot. Can be regarded as corresponding to the diameter of the bundle fiber, that is, the bundle fiber diameter. Here, the bundle fiber diameter is defined by the two end faces that are farthest from the end faces of the plurality of irradiation side fibers f1 and the end faces of the plurality of light receiving side fibers f2 arranged on the tip face of the optical sensor probe 13. The length is about 1.8 mm in this embodiment.

  The second difference is that the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm is at least twice the bundle fiber diameter. With such a configuration, the incident angle of light with respect to the thin film, in other words, the reflection angle of light reflected by the thin film is equal to or less than the numerical aperture NA of the light receiving side fiber f2. In the present embodiment, the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm is secured twice or more the bundle fiber diameter by utilizing the above properties. As a result, the light receiving efficiency when receiving light through the light receiving side fiber f2 is further increased, and the optical film thickness can be measured with higher accuracy.

  Further, if the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm becomes excessively short, the incident angle of light with respect to the thin film and the reflection angle of light reflected by the thin film increase. Since the light receiving efficiency of the optical sensor probe 13 (the ratio of the amount of light received by the optical sensor probe 13 to the amount of reflected light) is reduced, the measurement accuracy is lowered. On the other hand, if the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm becomes excessively long, the time from when the light is reflected by the thin film until it is received by the optical sensor probe 13. Since the degree of attenuation increases, the measurement accuracy decreases. On the other hand, if the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm is at least twice the bundle fiber diameter, preferably in the range of 2 to 3 times, it is preferable. Measurement accuracy can be achieved.

  Hereinafter, for convenience of explanation, the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm is referred to as an operating distance WD.

  The third difference is that while the multilayer film is formed on the actual substrate S, the same monitor substrate Sm is disposed in the vacuum vessel 1 and the multilayer film is also formed on the monitor substrate Sm. That is, in the present embodiment, the monitor substrate Sm is not replaced while the multilayer film is being formed on the actual substrate S. Then, the film thickness measuring device 6 measures the optical film thickness of each layer of the multilayer film formed on the monitor substrate Sm for each layer. As a result, when the optical film thickness of each layer of the multilayer film is measured for each layer, the influence caused by the change of the monitor substrate Sm for each measurement is suppressed.

  More specifically, some conventional film forming apparatuses for forming a multilayer film are equipped with a monitor substrate changer (not shown). In such an apparatus, each layer of the multilayer film is formed on the actual substrate S. Each time the monitor board changer is changed, the monitor board Sm is replaced. However, there are variations in size, surface condition, and processing accuracy between the monitor substrates, and this variation may affect the thin film measurement accuracy. That is, in terms of reproducibility of film thickness measurement, there is a problem in exchanging the monitor substrate during the formation of the multilayer film.

  On the other hand, in this embodiment, since the same monitor substrate Sm is continuously arranged in the vacuum vessel 1 during the period in which the multilayer film is formed on the actual substrate S, the influence caused by the variation between the monitor substrates Sm is reduced by the thin film. It does not reach the accuracy of measurement. Accordingly, the film thickness of each layer of the multilayer film formed on the monitor substrate Sm can be accurately measured, and the optical film thickness of the film formed on the actual substrate S side is more accurately based on the measurement result. It becomes possible to control well.

  In the present embodiment, as described above, an annular substrate is used as the monitor substrate Sm. On the film thickness measuring device 6 side, film thickness multipoint monitoring is possible. Furthermore, in this embodiment, the bundle fiber diameter is about 1.8 mm, and the optical sensor probe 13 is composed of 20 or more irradiation side fibers f1 and light receiving side fibers f2. As a result, in the film thickness measuring device 6 according to the present embodiment, the number of monitor points (number of measurement points) can be set to 80 points. In general, for the purpose of improving light quantity sensitivity, two types of vapor deposition layers of a high refractive index vapor deposition material and a low refractive index vapor deposition material are formed on the monitor substrate Sm. If so, for example, it is possible to deal with a case where a multilayer film composed of 160 layers (80 × 2) is formed.

  A fourth difference is a position where each end face of the irradiation side fiber f1 and the light receiving side fiber f2 is arranged on one end face of the small diameter portion 25b which is the tip face of the optical sensor probe 13. More specifically, in the present embodiment, each of the end faces of the plurality of irradiation side fibers f1 arranged adjacent to the end face of at least one light receiving side fiber f2 on the front end face of the optical sensor probe 13. It is arranged in an arc shape or an annular shape in a state. Similarly, on the one end face, each of the end faces of the plurality of light receiving side fibers f2 are arranged in an arc shape or an annular shape in a state of being adjacent to each of the end faces of at least one irradiation side fiber f1. ing.

  As described above, if the end face of the irradiation side fiber f1 and the end face of the light receiving side fiber f2 are adjacent to each other on the tip surface of the optical sensor probe 13, the incident light irradiated from the projector 11 onto the thin film is incident. The angle becomes smaller. Here, the magnitude of the incident angle is such that the light irradiated from the end face of the irradiation side fiber f1 travels toward the thin film, and the same light is reflected at the surface of the thin film or the boundary surface between the monitor substrate Sm and the thin film. Thus, it is ½ of the angle formed by the optical path toward the end face of the light receiving side fiber f2.

  On the other hand, since the relationship shown in the above-described equation (1) is established between the incident angle θ and the measured value d of the film thickness, the measurement error Δd of the film thickness increases as the incident angle θ increases. Become. Specifically, when the refractive index of the film forming material is n = 1.47, and the incident angle θ is 3 °, 5 °, 8 °, 10 °, and 12 °, the measurement error Δd is 0.07%, 0.2%, 0.5%, 0.7%, and 1.0%. In other words, the smaller the incident angle θ, the smaller the film thickness measurement error Δd.

  As described above, the proportion of the amount of light received through the light receiving side fiber f2 out of the amount of light reflected by the thin film, that is, the light receiving efficiency, as the end surface of the irradiation side fiber f1 and the end surface of the light receiving side fiber f2 are separated. Decreases. On the contrary, when the end face of the irradiation side fiber f1 and the end face of the light receiving side fiber f2 are adjacent to each other, the light receiving efficiency is improved.

  By the way, the accuracy of the film thickness measurement is improved as the filling rate of the fiber at the distal end surface of the optical sensor probe 13 is increased. Therefore, the end surfaces of the fibers are usually in a dense state in the distal end surface of the optical sensor probe 13. Be placed. On the other hand, as the end faces of the fibers are denser, the end faces of the irradiation side fibers f1 and the end faces of the light receiving side fibers f2 are more likely to be densely packed. If the end faces of the same type of fibers are densely arranged in a lump, the end face of the irradiation side fiber f1 and the end face of the light receiving side fiber f2 are easily separated.

On the other hand, if each fiber is arranged so that the end surface of the irradiation side fiber f1 and the end surface of the light receiving side fiber f2 are arranged in an arc shape or an annular shape on the tip surface of the optical sensor probe 13, the irradiation side fiber f1 is arranged. And a fiber arrangement such that the light receiving side fiber f2 is adjacent to each other can be efficiently realized.
In addition, as a fiber arrangement in which the irradiation side fiber f1 and the light receiving side fiber f2 are adjacent to each other, the end surface of the irradiation side fiber f1 and the end surface of the light receiving side fiber f2 are arranged on the tip surface of the optical sensor probe 13, respectively. None An arrangement in which rows of fibers of each type are arranged alternately is also conceivable. However, in the situation where the end faces of the fibers are densely arranged in the distal end face of the optical sensor probe 13 for the above reasons, the end face of the irradiation side fiber f1 and the end face of the light receiving side fiber f2 form a row respectively. A fiber arrangement in which rows of types of fibers are alternately arranged is difficult to physically implement. Therefore, it is more efficient and preferable to arrange each fiber so that the end faces of each type of fiber are arranged in an arc shape or an annular shape as in this embodiment.

  Due to the above-described operation, the film thickness measuring device 6 according to the present embodiment can measure the optical film thickness with higher accuracy than the conventional device.

  Next, specific examples (first to third examples) of the arrangement positions of the end faces of the irradiation side fiber f1 and the light receiving side fiber f2 on the distal end face of the optical sensor probe 13 will be described with reference to FIGS. While explaining.

  FIGS. 3A and 3B are diagrams showing fiber arrangement positions in the first example. FIG. 4 is a diagram showing the arrangement positions of the fibers in the comparative example. FIGS. 5A and 5B are diagrams showing the arrangement positions of the fibers in the second example. FIG. 6 is an explanatory diagram about the effectiveness of the arrangement position of the fiber according to the present embodiment, in which the solid line graph shows the data of the first example and the broken line graph shows the data of the comparative example. (A) and (B) of Drawing 7 are figures showing other variations about the 2nd example. FIGS. 8A and 8B are views showing the arrangement positions of the fibers in the third example. 3, 4, 6, 7, and 8, black circles indicate the arrangement positions of the irradiation side fibers f <b> 1, and white circles indicate the arrangement positions of the light reception side fibers f <b> 2.

  First, the arrangement position of the fibers in the first example will be described. As shown in FIGS. 3A and 3B, the irradiation side fiber f1 and the light receiving side fiber f2 are arranged, and the irradiation side fiber f1 and the light receiving side fiber f2 are arranged. They are arranged so as to form spirals that are opposite to each other, and the entire bundle has a circular arrangement. 3A and 3B show a configuration in which the arrangement position of the irradiation side fiber f1 and the arrangement position of the light receiving side fiber f2 are reversed with each other. Only the configuration shown in FIG.

  In the first example, as described above, the irradiation side fiber f1 and the light receiving side fiber f2 are arranged in a circular arc shape, more specifically, in a spiral shape. As a result, in the first example, it is possible to irradiate each part of the effective light projection range with a uniform light amount in the monitor substrate Sm, and further, the light reflected by the monitor substrate Sm is subjected to a uniform condition. Can receive light.

  In the first example, the maximum incident angle is about 8.4 °, and the effective incident angle is about 1.5 °. Here, the maximum incident angle corresponds to half of the angle between the irradiation-side fiber f1 and the light-receiving side fiber f2 that are farthest from each other on the distal end surface of the optical sensor probe 13, and in FIG. This corresponds to half of the angle formed by the optical path of the light emitted from the irradiation side fiber f1 located on the outermost side and the optical path of the light directed to the light receiving side fiber f2 located in the center of the bundle. The effective incident angle corresponds to half of the angle formed by the optical path of light emitted from the irradiation side fiber f1 and the optical path of light directed to the light receiving side fiber f2 adjacent to the fiber f1.

  The effectiveness of the arrangement position of the fiber according to the first example will be described. In the first example, the maximum incident angle and the effective incident angle are smaller than those of the comparative example illustrated in FIG. More specifically, in the comparative example, the plurality of irradiation side fibers f1 are gathered in a semicircular shape, and the plurality of light receiving side fibers f2 are gathered in a semicircular shape. It has become.

  In the comparative example, the maximum incident angle is about 11.1 °, and the effective incident angle is about 6 °. Here, the maximum incident angle in the comparative example is an angle formed by the optical path of the light irradiated from the irradiation side fiber f1 located on the outermost side and the optical path of the light toward the light receiving side fiber f2 farthest from the fiber f1. Equivalent to half of Further, the effective incident angle in the comparative example corresponds to half of the angle formed by the optical path of the light emitted from the irradiation side fiber f1 at the center of gravity and the optical path of the light toward the light receiving side fiber f2 at the center of gravity. . The center-of-gravity position is the center-of-gravity position of the fiber group assembled in a semicircular shape. When the diameter of the semicircle formed by the fiber group is r, the relative position of the center of gravity with respect to the center of the semicircle is It can be represented by the coordinates (0, 2r / π).

  As described above, in the first example, the maximum incident angle and the effective incident angle are smaller than in the comparative example. In the first example, the degree of dispersion of each of the irradiation side fiber f1 and the light receiving side fiber f2 is larger than that of the comparative example, and the proportion of the irradiation side fiber f1 adjacent to the light receiving side fiber f2, and This is because the proportion of the light receiving side fiber f2 adjacent to the irradiation side fiber f1 becomes higher. Thereby, in the first example, the effective light projection range is smaller than in the comparative example, and the measurement error of the optical film thickness is also reduced.

  Further, in the first example, the relative reflected light amount (ratio of the amount of reflected light to the amount of incident light) in the range where the operating distance WD is 0 to 7 mm is larger than that of the comparative example. Therefore, when the operating distance WD is in the range of 0 to 7 mm, the first example can receive the reflected light with a higher amount of light than the comparative example. Thereby, the accuracy of the spectroscopic analysis in the spectroscope 14 is improved, and as a result, the measurement accuracy of the optical film thickness is improved.

  Next, the arrangement position of the fibers in the second example will be described. As shown in FIGS. 5A and 5B, the irradiation side fibers f1 and the light receiving side fibers f2 are arranged in an annular shape, and each fiber f1. , F2 are alternately arranged concentrically. 5A and 5B show a configuration in which the arrangement position of the irradiation side fiber f1 and the arrangement position of the light receiving side fiber f2 are reversed with each other. Hereinafter, FIG. Only the configuration shown in FIG.

  In the second example, as described above, the irradiation-side fiber f1 and the light-receiving side fiber f2 are arranged in an annular shape, and thereby, uniform in each part of the effective light projection range of the monitor substrate Sm. Light can be irradiated with the amount of light, and the light reflected by the monitor substrate Sm can be received under uniform conditions.

  In the second example, the maximum incident angle is about 4.2 °, and the effective incident angle is about 1.5 °. Furthermore, as shown in FIG. 6, in the second example, the amount of relative reflected light in the range where the operating distance WD is 0 to 7 mm is larger than that in the comparative example. For this reason, when the operating distance WD is in the range of 0 to 7 mm, the second example can receive reflected light with a higher amount of light compared to the comparative example. The accuracy of analysis is improved, and the measurement accuracy of the optical film thickness is improved.

  In addition, as another variation which arrange | positions each fiber in an annular | circular shape, as shown to (A) and (B) of FIG. 7, in the annular ring located in the outermost side among the annular rings which the irradiation side fiber f1 makes. A configuration in which the irradiation side fiber f1 is replaced with the light receiving side fiber f2 at an interval of about 90 ° is also conceivable. By adopting such an arrangement, in the second example, the difference between the proportion occupied by the light receiving side fiber f2 and the proportion occupied by the irradiation side fiber f1 in the number of fibers in the bundle is larger than in the first example. Get smaller. That is, it is desirable that the number of the irradiation side fibers f1 and the number of the light receiving side fibers f2 are close to each other for the function of the probe. For this reason, the fiber arrangement as shown in FIGS. 7A and 7B is adopted. It is good to do.

  Next, the fiber arrangement position in the third example will be described. In the third example, each of the irradiation side fiber f1 and the light receiving side fiber f2 is not arranged in an arc shape or an annular shape, and is different from the first example and the second example described above in this respect. Specifically, in the third example, as shown in FIGS. 8A and 8B, the irradiation side fibers f1 arranged in a substantially V-shape are 5 at regular intervals along the outer periphery of the bundle. The light receiving side fibers f2 are arranged so as to fill the gaps and the center of the bundle, and the whole bundle has a circular arrangement. In the third example, the maximum incident angle is about 8.4 °, and the effective incident angle is about 1.5 °. Therefore, also in the third example, the maximum incident angle and the effective incident angle are reduced as compared with the comparative example, and the effective light projection range is also reduced. 8A and 8B show a configuration in which the arrangement position of the irradiation side fiber f1 and the arrangement position of the light receiving side fiber f2 are reversed with respect to each other.

  Although the film thickness measuring apparatus and the film forming apparatus according to the present embodiment have been described above, the present embodiment is only an example for facilitating the understanding of the present invention, and the above-described members, arrangements, and the like are as follows. The present invention is not limited, and various modifications and improvements can be made in accordance with the spirit of the present invention, and the present invention includes the equivalents. For example, the contents described above as the size, dimension, shape, and material of each device constituting the thin film measuring apparatus are merely examples for demonstrating the effects of the present invention, and do not limit the present invention.

  In the above-described embodiment, the vacuum deposition apparatus 100 that forms a film by a vacuum deposition method has been described as an example of the film deposition apparatus. However, the deposition apparatus that forms a film by an ion plating method and the film deposition by an ion beam deposition method have been described. The present invention can also be applied to the film forming apparatus. The present invention is also applicable to a film forming apparatus that employs a sputtering method in which a film is formed by colliding ions with a target.

  In the above-described embodiment, for the purpose of improving the light receiving efficiency of the reflected light, the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm, that is, the operating distance WD is set to the bundle fiber diameter. We decided to make it more than twice. However, the present invention is not limited to this, and the distance between the tip surface of the optical sensor probe 13 and the film formation surface of the monitor substrate Sm may be less than twice the bundle fiber diameter.

  In the above embodiment, an annular substrate is used as the monitor substrate Sm. An annular substrate is effective, for example, when performing film thickness measurement with a quartz film thickness meter together with measurement of optical film thickness. In general, in a film forming apparatus using an annular monitor substrate Sm, the crystal film thickness meter is disposed at a position corresponding to the center of the apparatus, specifically the center of the substrate holder 2 for reasons of the structure of the apparatus. It is because it can do. However, the monitor substrate Sm is not limited to an annular substrate, and may be a substrate having another shape, for example, a disk-shaped substrate.

  In the above embodiment, the monitor substrate Sm is not replaced during the period in which the multilayer film is formed on the actual substrate S, and the multilayer film is formed on the monitor substrate Sm side. However, the present invention is not limited to this. It is not something. That is, the monitor substrate Sm may be replaced each time a film of each layer in the multilayer film is formed. However, as described above, there are variations in size, surface condition, and processing accuracy between the monitor substrates. If the monitor substrate Sm is replaced every time the film thickness of each layer is measured, the variation affects the measurement accuracy. End up. In this respect, it is desirable not to replace the monitor substrate Sm during the period in which the multilayer film is formed on the actual substrate S.

  In the above embodiment, the film forming apparatus that forms a multilayer film on the actual substrate S has been described as an example. However, the present invention can also be applied to an apparatus that forms a single layer film on the actual substrate S.

1 Vacuum container 2 Substrate holder
2a Aperture 3 Evaporation mechanism 4 Shutter 5 Shutter control unit 6 Film thickness measuring device 11 Projector 12 DC stabilized power supply 13 Optical sensor probe 14 Spectrometer 15 Amplifier 16 A / D converter 17 Signal processing circuit 21 Light source 22 Light receiving device 23 Flexible Tube 24A Connection connector 24B Connection connector 24C Intermediate connector 25 Protective cylinder 25a Large diameter portion 25b Small diameter portion 100 Vacuum deposition apparatus f1 Irradiation side fiber f2 Light reception side fiber PC1 First computer PC2 Second computer PLC Programmable logic controller S Real substrate Sm Monitor substrate

Claims (6)

In order to measure the optical film thickness of the film formed on the substrate to be measured, an irradiation apparatus that irradiates light toward the substrate to be measured through an irradiation side fiber made of an optical fiber;
In order to measure the optical film thickness, a light receiving device that receives light reflected from the substrate to be measured after being irradiated from the irradiation device through a light receiving side fiber made of an optical fiber;
A probe formed by bundling a plurality of the irradiation side fibers and a plurality of the light receiving side fibers,
A plurality of end faces of the irradiation side fiber and a plurality of end faces of the light receiving side fiber are arranged on the facing surface provided on the side facing the substrate to be measured as the end face,
In the facing surface, each of the plurality of end faces of the irradiation side fibers arranged in an arc shape or an annular shape adjacent to the end face of at least one of the light receiving side fibers is arranged in a plurality. Each of the end faces of the light receiving side fibers is arranged in an arc or an annular shape in a state adjacent to each of the end faces of at least one of the irradiation side fibers ,
A row formed by the end faces of the irradiation side fibers arranged in an arc shape or an annular shape, and a row formed by the end faces of the light receiving side fibers arranged in an arc shape or an annular shape are opposed to each other from an arbitrary point on the outer circumference of the facing surface. It is arranged so that it is alternately switched at least 3 times toward the inside of the surface,
The probe has a state in which no optical component is provided between the facing surface and the substrate to be measured, and the side of the substrate to be measured on which the film is formed on the facing surface. A film thickness measuring apparatus which is opposed to a non-film forming surface located on the opposite side . The plurality of irradiation side fibers and the plurality of light receiving side fibers constituting the probe are bundle fibers whose end faces are aligned on the facing surface,
The distance between the counter surface and the deposition surface, the film thickness measurement apparatus according to claim 1, characterized in that at least twice the diameter of the bundle fiber. The film thickness measuring device according to claim 2 , wherein the substrate to be measured is a disk-shaped or annular substrate. The irradiation device;
A direct current stabilizing power source for supplying direct current to a light source provided in the irradiation device;
The probe;
A spectroscope comprising the light receiving device, and outputting an analog signal corresponding to a light receiving intensity when the light receiving device receives light reflected by the substrate to be measured;
An amplifier for amplifying the analog signal output from the spectrometer;
An A / D converter for converting the analog signal amplified by the amplifier into a digital signal;
An electronic calculator that calculates the optical film thickness based on the digital signal;
A signal processing circuit that is interposed between the A / D converter and the electronic computer, and for performing predetermined signal processing on the digital signal when the electric computer calculates the optical film thickness; thickness measuring system according to any one of claims 1 to 3, characterized in that it has. A film forming apparatus for forming a film on the substrate by depositing a deposition material on the surface of the substrate in a vacuum container,
An evaporation mechanism for evaporating the vapor deposition material;
An opening / closing member that opens and closes to block a path when the vapor deposition material evaporated by the evaporation mechanism travels to the surface of the substrate;
A control mechanism for controlling opening and closing of the opening and closing member;
A film thickness measuring apparatus according to any one of claims 1 to 4 ,
In a state where both the substrate and the substrate to be measured are accommodated in the vacuum vessel, the evaporation mechanism evaporates the vapor deposition material to deposit the vapor deposition material on both surfaces, and the film thickness measurement The apparatus measures the optical film thickness of the film formed on the substrate to be measured, and the control mechanism controls the opening / closing of the opening / closing member according to the measurement result of the optical film thickness by the film thickness measuring apparatus. A film forming apparatus. While the multilayer film is formed on the substrate, the same substrate for measurement is disposed in the vacuum vessel to form the multilayer film on the substrate for measurement.
6. The film forming apparatus according to claim 5 , wherein the film thickness measuring apparatus measures the optical film thickness of each film in the multilayer film formed on the substrate to be measured for each layer.

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