Film thickness measuring device, film forming system, and film thickness measuring method

Abstract

To suppress variations in measurement results of the film thickness of a substrate on a mounting table on which the substrate is mounted due to tilting of the mounting table.SOLUTION: A film thickness measuring device measuring the thickness of a film formed on a substrate is provided, comprising a mounting table on which the substrate is mounted, a light receiving and emitting unit which emits light for film thickness measurement to the substrate on the mounting table and receives reflected light of the emitted light from the substrate on the mounting table, a rotating mechanism rotating the mounting table, an orientation detection unit that detects the orientation of the mounting table, and a control unit, the control unit controls the rotating mechanism on the basis of the detection result of the orientation detection unit in such a way that the mounting table is oriented in a desired direction when the substrate is mounted.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a film thickness measurement apparatus, a film formation system, and a film thickness measurement method. [Background technology]

[0002] Patent Document 1 discloses a vacuum processing apparatus for forming a laminated film used in MRAM (Magnetoresistive Random Access Memory). When manufacturing a laminated film, this vacuum processing apparatus sequentially uses processing modules surrounding a transfer module to perform a series of multiple processes on a substrate in a vacuum atmosphere.

[0003] Patent Document 2 discloses a method that enables in-situ measurement of the film growth process when oxide superconducting films are formed on various substrates by chemical vapor deposition. Patent Document 3 discloses a clustered semiconductor device manufacturing apparatus including at least a first reaction chamber for performing a first process on a substrate and a second reaction chamber for performing a second process on the substrate. This manufacturing apparatus is configured to be able to maintain a common space including the first reaction chamber and the second reaction chamber in an atmosphere isolated from the standby atmosphere, and to be able to transport a substrate between the first reaction chamber and the second reaction chamber. The manufacturing apparatus also includes an optical measuring means for evaluating the surface condition of the substrate in terms of gloss while the substrate is grounded at any position in the common space. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6160614 [Patent Document 2] Japanese Patent Application Publication No. 5-149720 [Patent Document 3] Japanese Patent Application Publication No. 11-330185 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology disclosed herein suppresses variation in the measurement results of the film thickness of a substrate placed on a mounting table caused by tilting of the mounting table on which the substrate is placed. [Means for solving the problem]

[0006] One aspect of the present disclosure is a film thickness measurement device for measuring the thickness of a film formed on a substrate, the device comprising: a mounting stage on which a substrate is placed; a light receiving and emitting unit that emits light for film thickness measurement to a substrate on the mounting stage and receives light of the emitted light reflected by the substrate on the mounting stage; a rotation mechanism that rotates the mounting stage; an orientation detection unit that detects an orientation of the mounting stage; and a control unit, the control unit controlling the rotation mechanism based on a detection result by the orientation detection unit so that the orientation of the mounting stage relative to the light receiving and emitting unit when the substrate is placed on the mounting stage becomes a predetermined reference orientation; The apparatus further includes a distance measuring unit that measures a distance from the light receiving and emitting unit to an irradiation point of the light of the light receiving and emitting unit on the substrate on the mounting table, and an adjustment mechanism that adjusts the distance from the light receiving and emitting unit to the irradiation point, and the control unit further controls the adjustment mechanism based on a measurement result by the distance measuring unit. do. Effect of the Invention

[0007] According to the present disclosure, it is possible to suppress variation in the measurement results of the film thickness of the substrate placed on the mounting table caused by tilting of the mounting table on which the substrate is placed. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic plan view showing an example of a film forming system including a film thickness measuring device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical cross-sectional view showing an example of a film thickness measuring device. [Diagram 3] FIG. 4 is a functional block diagram of a control unit related to film thickness measurement. [Figure 4] 11A and 11B are diagrams for explaining the reason for adjusting the orientation of the stage when the substrate is placed on the stage. [Diagram 5] 11A and 11B are diagrams for explaining the reason for adjusting the orientation of the stage when the substrate is placed on the stage. [Figure 6]13 is a flowchart illustrating an example of a teaching method for a reference orientation of a stage. [Figure 7] 1 is a flowchart for explaining an example of a film thickness measuring method using the film thickness measuring device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Magnetic devices such as MRAM and magnetic heads for HDDs (Hard Disk Drives) use laminated films formed by stacking a large number of extremely thin films, such as 10 nm or less. A known film formation system for forming such laminated films is one in which multiple processing devices are connected to a vacuum transport device, and each layer of film is formed in turn by each processing device.

[0010] In addition, it is required to confirm whether each formed film has a desired thickness without removing the film from the portion of the film forming system under a vacuum atmosphere. For this reason, it has been considered to measure the thickness of the film formed by the processing device of the film formation system in-situ. Specifically, for example, it has been considered to provide a film thickness measuring device connected to a vacuum transport device and having a vacuum atmosphere inside the film formation system, transport a substrate on which a film has been formed by the processing device from the processing device to the film thickness measuring device by the vacuum transport device, and measure the thickness of the film on the substrate by the film thickness measuring device.

[0011] The film thickness measuring device as described above is considered to have a container, a mounting table, a light receiving and emitting unit, and a moving mechanism. The above-mentioned container is configured to be decompressible, and has a mounting table provided therein. A substrate is placed on the mounting table. The light receiving and emitting unit has a light emitting section that emits light for film thickness measurement onto the substrate on the mounting table, and a light receiving section that receives light emitted from the light emitting section and reflected by the substrate on the mounting table. The moving mechanism moves the irradiation point of light from the light emitting section onto the substrate on the mounting table. The rotating mechanism rotates the mounting table, and constitutes, for example, a part of the moving mechanism. In the film thickness measuring device having this configuration, the irradiation point is moved by the moving mechanism, and for each irradiation point, the film thickness of the portion of the substrate corresponding to the irradiation point is calculated based on the result of reception of the reflected light by the light receiving unit, thereby obtaining the in-plane distribution of the thickness of the film formed on the substrate.

[0012] However, even if the tilt of the mounting table (specifically, the tilt of the mounting surface on which the substrate is placed relative to the horizontal plane) is adjusted during the assembly of the film thickness measuring device, the tilt (specifically, the tilt of the mounting surface on which the substrate is placed relative to the horizontal plane) cannot be made 0°. For example, the mounting table after adjustment tilts by about 0.02°. In addition, currently, the orientation (rotation angle) of the mounting table when the substrate is placed on the mounting table is not managed. This point is not particularly problematic when the film thickness of the measurement target is thick and precision is not required, but when the film thickness of the measurement target is thin, such as 10 nm or less and precision is required, it was predicted that the measurement results (including the distribution of film thickness within the substrate surface) by the film thickness measuring device will differ for each substrate even if the film formation recipe is the same. In fact, the inventors' intensive investigation confirmed that this prediction was correct.

[0013] In view of this, the technology disclosed herein suppresses variation in the measurement results of the film thickness of the substrate placed on the mounting table from substrate to substrate, which is caused by tilting of the mounting table on which the substrate is placed.

[0014] Hereinafter, a film thickness measurement device, a film formation system, and a film thickness measurement method according to the present embodiment will be described with reference to the drawings. In this specification, elements having substantially the same functional configurations are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0015] <Film formation system> FIG. 1 is a schematic plan view showing an example of a film forming system including a film thickness measuring device according to this embodiment.

[0016] The film formation system 1 has a configuration in which a cassette station 10, into which cassettes C capable of accommodating semiconductor wafers (hereinafter referred to as "wafers") W as a plurality of substrates are loaded and unloaded, and a processing station 11, which performs a plurality of processes including a magnetic film formation process on the wafers W, are integrally connected. The cassette station 10 and the processing station 11 are connected via a load lock device 12. The load lock device 12 is provided so as to connect an atmospheric pressure transfer device 21 and a vacuum transfer device 30, which will be described later. The load lock device 12 is configured so that its interior can be switched between an atmospheric pressure state and a vacuum state.

[0017] The cassette station 10 has a cassette mounting table 20 and an atmospheric pressure transfer device 21. The cassette station 10 may further be provided with an orienter (not shown) for adjusting the orientation of the wafer W.

[0018] The cassette mounting stage 20 is provided at an end portion on the negative Y-direction side (the downward direction in FIG. 1) of the film forming system 1. The cassette mounting stage 20 is adapted to mount a plurality of cassettes C, for example, three cassettes C thereon.

[0019] The atmospheric pressure transfer device 21 transfers the wafer W at atmospheric pressure using a wafer transfer mechanism (not shown). The wafer transfer mechanism has a transfer arm that holds the wafer W substantially horizontally, and this transfer arm is configured to be rotatable and extendable, and is also provided so as to be able to move up and down in the vertical direction and move horizontally. The wafer transfer mechanism transfers the wafer W while holding it using this transfer arm. The load lock device 12 is connected to the atmospheric pressure transfer device 21 on the positive Y direction side (upward in FIG. 1) via a gate valve G1. The load lock device 12 is connected to the vacuum transfer device 30 of the processing station 11, specifically, to a vacuum transfer chamber 31 (described later), on the positive Y direction side via a gate valve G2. 1 is connected.

[0020] The processing station 11 includes a vacuum transport device 30 and a plurality of (six in this example) processing devices 40.1 ~40 6 (Hereinafter, some or all of these may be collectively referred to as "processing device 40") and a film thickness measurement device 60. The vacuum transfer device 30, the inside of the processing device 40, and the film thickness measurement device 60 are each maintained in an atmosphere reduced below atmospheric pressure (vacuum atmosphere) during a series of processes on the wafer W in the film formation system 1.

[0021] The vacuum transfer device 30 includes a relay chamber 32 1 , 32 2 (Hereinafter, they may be collectively referred to as "relay chambers 32"), and a plurality of (three in this example) vacuum transfer chambers 31 are connected to the transfer chambers 31 via the relay chambers 32. 1 ~31 3 (Hereinafter, some or all of these may be collectively referred to as "vacuum transfer chamber 31.") The vacuum transfer chamber 31 and the relay chamber 32 each have a housing having a sealable structure and formed to have a substantially polygonal shape in a plan view.

[0022] On the outside of the vacuum conveying device 30 in the negative X direction (left direction in the figure), the processing device 40 is moved along the Y direction (up and down direction in the figure). 1 ~40 3 are provided, each connected to a corresponding vacuum transfer chamber 31. 1 However, the vacuum transfer chamber 31 is opened via the gate valves G11 and G12. 1 , vacuum transfer chamber 31 2 and a processing unit 40 2 However, through gate valves G13 and G14, the vacuum transfer chamber 31 2 , vacuum transfer chamber 31 3 and a processing unit 40 3 However, through the gate valve G15, the vacuum transfer chamber 31 3 is connected to

[0023] Further, on the outside of the vacuum conveying device 30 in the positive X direction (the right direction in the figure), the processing device 40 is arranged along the Y direction (the up-down direction in the figure). 4 ~40 6are provided, each connected to a corresponding vacuum transfer chamber 31. 4 However, through the gate valve G16, the vacuum transfer chamber 31 3 and a processing unit 40 5 However, through gate valves G17 and G18, the vacuum transfer chamber 31 3 , vacuum transfer chamber 31 2 and a processing unit 40 6 However, through gate valves G19 and G20, the vacuum transfer chamber 31 2 , vacuum transfer chamber 31 1 is connected to

[0024] Furthermore, a film thickness measuring device 60 is disposed outside the vacuum transfer device 30 in the positive Y direction (upward in the figure). 3 is connected to

[0025] Each vacuum transfer chamber 31 takes out a wafer W from a module adjacent to the vacuum transfer chamber 31 (processing device 40, relay chamber 32, load lock device 12, film thickness measurement device 60), and transfers the wafer W to another module adjacent to the vacuum transfer chamber 31.

[0026] Further, a wafer transfer mechanism 50 for transferring the wafer W is provided inside each vacuum transfer chamber 31. The wafer transfer mechanism 50 has a transfer arm 51 for holding the wafer W substantially horizontally. The transfer arm 51 is configured to be extendable and rotatable in the horizontal direction. The wafer transfer mechanism 50 also has an elevation unit 52 provided below the transfer arm 51. The transfer arm 51 is configured to be able to move up and down freely in the vertical direction by the elevation unit 52. The wafer transfer mechanism 50 is configured to transfer the wafer W while holding it with the transfer arm 51. In the following, the wafer transfer mechanism 50 will be referred to as the wafer transfer mechanism 50. n , Transport arm 51 n (n=1 to 3) are vacuum transfer chambers 31 n and a transfer arm 51 of the wafer transfer mechanism 50.

[0027] The relay chamber 32 is a module used when transferring the wafer W directly between adjacent vacuum transfer chambers 31 without using the processing device 40. The internal spaces of the adjacent vacuum transfer chambers 31 communicate with each other via the internal space of the relay chamber 32, thereby enabling the transfer. The relay chamber 32 and the vacuum transfer chamber 31 may be connected via a gate valve.

[0028] Processing device 40 1 ~40 6 are used to form multiple films on a wafer W, i.e., to form a laminated film, and include those that actually perform film formation processes such as PVD processing, and may also include those that perform cleaning processes, pre-processing, cooling processes, etc. The processing performed on the wafer W may differ for each processing apparatus 40, or the processing performed on the wafer W may be common to some of the processing apparatuses 40.

[0029] The film thickness measuring device 60 measures the thickness of a film formed in any one of the processing devices 40 and the thickness of a laminated film formed in the processing station 11. The position of the film thickness measuring device 60 is not limited to the position in this example. Furthermore, the film formation system 1 may have a plurality of film thickness measuring devices 60. Details of the film thickness measuring device 60 will be described later.

[0030] The film forming system 1 configured as above is provided with a control unit 70. The control unit 70 is configured by a computer equipped with, for example, a CPU, a memory, and the like, and has a storage unit (not shown) that stores various information. The storage unit stores, for example, a program for controlling the driving units of each device and each mechanism to realize wafer processing described below in the film forming system 1, a program for controlling the driving units, and the like to realize film thickness measurement by the film thickness measuring device 60, and the like. The above programs may be recorded in a non-transitory storage medium readable by a computer and installed in the control unit 70 from the storage medium.

[0031] Next, a wafer processing using the film forming system 1 configured as above will be described.

[0032] First, a cassette C containing a plurality of wafers W is carried into the cassette station 10 of the film forming system 1 and placed on the cassette mounting table 20. Then, one wafer W is removed from the cassette C by a wafer transfer mechanism (not shown) of the atmospheric pressure transfer device 21, the gate valve G1 is opened, and the wafer W is carried into the load lock device 12. Once the wafer W is carried into the load lock device 12, the gate valve G1 is closed to hermetically seal the load lock device 12 and reduce the pressure inside. Then, the gate valve G2 is opened, and the load lock device 12 and the vacuum transfer chamber 31, which has been previously set to a vacuum atmosphere, are connected to each other. 1 Then, the wafer transfer mechanism 50 1 Transport arm 51 1 The wafer W is transferred from the load lock device 12 to the vacuum transfer chamber 31. 1 It is brought inside.

[0033] Next, the gate valve G2 is closed and the gate valve G11 is opened, and the vacuum transfer chamber 31 1 and processing device 40 1 Then, the wafer transfer mechanism 50 1 Transport arm 51 1 The wafer W is then processed by the processing device 40. 1 It is brought inside.

[0034] Thereafter, the gate valve G11 is closed, and the processing device 40 1 After the processing device 40 is sealed, 1 In the chamber, the wafer W is subjected to a predetermined process.

[0035] Processing device 40 1 When the processing in the processing apparatus 40 is completed, the gate valve G12 is opened and the processing apparatus 40 1 and vacuum transfer chamber 31 2 Then, the wafer transfer mechanism 50 2 Transport arm 51 2 The wafer W is then transported to the processing device 401 and is carried out from the vacuum transfer chamber 31 2 It is brought inside.

[0036] Thereafter, in the same manner as described above, the gate valves G12 to G20, G2 and the transfer arm 51 2 ~51 4 The driving sources such as are driven, and the wafer W is transferred in and out between the vacuum transfer chamber 31 and the processing device 40 etc. so that the wafer W is transferred in the following order. Processing device 40 1 → Vacuum transfer chamber 31 3 → Processing device 40 3 → Vacuum transfer chamber 31 3 → Processing device 40 4 → Vacuum transfer chamber 31 3 → Processing device 40 5 → Vacuum transfer chamber 31 2 → Processing device 40 6 → Vacuum transfer chamber 31 1 → Load lock device 12 And each processing device 40 1 ~40 6 The wafer W is subjected to a predetermined process.

[0037] The wafer W returned to the load lock device 12 is returned to the original cassette C in the reverse order to the procedure used when it was carried in from the cassette C. The series of wafer processes as described above is performed on each wafer W, and a laminated film is formed on each wafer W.

[0038] In such a series of wafer processing steps, if it is necessary to measure the thickness of a film after the film has been formed, the wafer W on which the film has been formed is transferred to the film thickness measuring device 60, where the film thickness is measured. In this case, the wafer W is transferred from the processing device after film formation by the wafer transfer mechanism 50 in the corresponding vacuum transfer chamber, and is transferred to one or more wafer transfer mechanisms 50 as necessary. Then, the gate valve G21 is opened, and the wafer W is transferred to the wafer transfer mechanism 50. 3The wafer is transported to the film thickness measuring device 60 by the transport mechanism 62. The film thickness may be measured each time a film formation process is performed in a processing device for film formation, or may be measured after film formation processes are performed in several processing devices, or may be measured after all films are formed.

[0039] <Film thickness measuring device 60> Next, the film thickness measuring device 60 will be described with reference to Fig. 2. Fig. 2 is a vertical cross-sectional view showing an example of the film thickness measuring device 60.

[0040] 2, the film thickness measuring apparatus 60 has a chamber 100 as a container configured to be capable of reducing the pressure. A stage 110 as a mounting table on which a wafer W is placed is provided in the chamber 100.

[0041] Specifically, the stage 110 has a wafer W placed on its upper surface. The stage 110 is configured to be rotatable and movable up and down. A wafer transfer mechanism 50 transfers the wafer W to the stage 110. 3 A lifter (not shown) used for transferring the wafer W between the stage 110 and the stage 110 is provided so as to be protrudable and retractable from the surface of the stage 110. The stage 110 may be provided with a temperature adjustment mechanism such as a heater to adjust the temperature of the wafer W placed on the stage 110. The temperature adjustment mechanism may be used to perform a heating process or a cooling process on the wafer W.

[0042] A support shaft 111 is connected to the center of the bottom surface of the stage 110. The support shaft 111 passes through a through hole 101a formed in the bottom wall 101 of the chamber 100, extends to the bottom of the chamber 100, and is connected to a rotation mechanism 112.

[0043] The rotation mechanism 112 rotates the stage 110, specifically, rotates the stage 110 via a support shaft 111. The rotation mechanism 112 has a drive unit 113 that drives the rotation of the stage 110. The drive unit 113 has, for example, a motor 114 as a drive unit that generates a driving force for the above-mentioned rotation. The motor 114 has a rotating shaft (not shown) connected to the support shaft 111. In addition, the drive unit 113 has an absolute encoder 115 connected to the motor 114.

[0044] The absolute encoder 115 has a rotating shaft (not shown) that is coaxial with the rotating shaft of the motor 114, and detects, for example, the rotation angle of the rotating shaft of the motor 114. Specifically, the absolute encoder 115 forms a light transmission / non-transmission pattern by a slit pattern formed on a rotating plate, and detects the rotation position of the rotating shaft of the motor 114 from an arbitrary reference point, i.e., the rotation angle (absolute angle), from this pattern. The rotation angle of the rotating shaft of the motor 114 coincides with the amount of rotation of the support shaft 111 connected to the stage 110, and therefore coincides with the rotation angle of the stage 110, i.e., the orientation of the stage 110. In other words, the absolute encoder 115 is an orientation detection unit that detects the orientation (rotation angle) of the stage 110. The motor 114 is controlled by the control unit 70, and the detection result of the absolute encoder 115 is output to the control unit 70.

[0045] Furthermore, the rotation mechanism 112 is attached to a lift plate 116, and a lift mechanism 117 serving as an adjustment mechanism is connected to the lift plate 116. The lift mechanism 117 is formed of, for example, a piezoelectric actuator, and raises and lowers the stage 110 via the lift plate 116 and the support shaft 111. This allows fine adjustment of the height of the stage 110. The lift mechanism 117 is controlled by the control unit 70. An expandable bellows 118 is provided airtightly between the bottom wall 101 and the lift plate 116 so as to surround the support shaft 111.

[0046] An exhaust port 101b is formed in the bottom wall 101 of the chamber 100, and an exhaust pipe 120 is connected to the exhaust port 101b, and an exhaust mechanism 121 having a pressure control valve and a vacuum pump is connected to the exhaust pipe 120. By operating the exhaust mechanism 121, the inside of the chamber 100 can be made into a vacuum atmosphere.

[0047] A side wall 102 of the chamber 100 is provided with a loading / unloading port 102a for the wafer W, and the loading / unloading port 102a can be opened and closed by the above-mentioned gate valve G21.

[0048] A thin and long through hole 103a extending in the radial direction of the wafer W is formed in a top wall (lid) 103 of the chamber 100. The through hole 103a is covered by a light-transmitting member 130 made of, for example, quartz, through which light for film thickness measurement and a laser for distance measurement, which will be described later, can pass. A seal ring 131 seals the space between the light-transmitting member 130 and the top wall 103.

[0049] An optical assembly 140 is provided in the atmospheric region above a position corresponding to the through hole 103a of the chamber 100. The optical assembly 140 has a main body 141, an optical receiving / emitting unit 142, and a laser unit 143.

[0050] A light receiving / emitting unit 142 and a laser unit 143 are attached to the main body 141 in a state adjacent to each other.

[0051] The light receiving and emitting unit 142 emits light L1 for film thickness measurement toward the wafer W on the stage 110, and receives the emitted light L1 reflected by the wafer W on the stage 110. The light receiving and emitting unit 142 has a light emitting section (not shown) that emits the light L1 for film thickness measurement toward the wafer W, and a light receiving section (not shown) that receives, i.e., detects, the reflected light.

[0052] The light emitting portion emits light L1 guided from the light source portion 144 via the optical fiber 145. The light emitted from the light emitting portion is irradiated onto the wafer W on the stage 110 via the light-transmitting member 130 and the transparent hole 103a. The light source unit 144 includes a light source, an amplifier for amplifying the light from the light source, etc. As the light source, a lamp light source that emits broad light with a short wavelength of about 800 nm or less can be used. The light receiving section has a light receiving sensor (not shown) that receives, i.e. detects, the reflected light described above.

[0053] The light emitting unit (specifically, the light source unit 144) is controlled by the control unit 70, and the result of receiving the reflected light by the light receiving unit is output to the control unit 70. The control unit 70 measures the thickness of the film formed on the wafer W based on the result of receiving the reflected light.

[0054] The laser unit 143 has a laser emitting section that emits a distance measurement laser L2 downward, i.e., toward the stage 110, and a laser receiving section that receives reflected light of the emitted laser L2 by a wafer W on the stage 110 or reflected light by a stage 110 on which no wafer W is placed. The laser emission unit emits laser light guided from the laser light source unit 146 via the optical fiber 147. The laser light emitted from the laser emission unit passes through the light-transmitting member 130 and the transparent hole 103a and is irradiated onto the wafer W on the stage 110 or the stage 110. The laser light receiving portion has a light receiving sensor (not shown) that receives, i.e. detects, the reflected light described above.

[0055] The laser emission section (specifically, the laser light source section 146) is controlled by the control section 70, and the result of reception of the reflected light of the laser light (hereinafter sometimes referred to as "reflected laser light") by the laser receiving section is output to the control section 70. Based on the result of reception of the reflected laser light, the control section 70 measures the distance between the light receiving / emitting unit 142 and the wafer W, specifically, the distance d (hereinafter sometimes referred to as "relative working distance d") between the light receiving sensor of the light receiving section of the light receiving / emitting unit 142 and the wafer W on the stage 110. For example, the laser light source section 146, the optical fiber 147, and a distance estimation section described later constitute a distance measurement section.

[0056] Moreover, above the chamber 100, a horizontal movement mechanism 150 is provided. The horizontal movement mechanism 150 has a linear guide 151 that guides the main body 141 of the optical assembly 140. The linear guide 151 is supported by the top wall 103 of the chamber 100 via a support member 152 and is disposed horizontally so as to extend in the device depth direction (Y direction in the figure) that coincides with the radial direction of the stage 110.

[0057] The main body 141 of the optical assembly 140 is configured as a slider guided by a linear guide 151. The horizontal movement mechanism 150 has a drive unit 153 that drives the movement of the main body 141 along the linear guide 151. The drive unit 153 has, for example, a motor as a drive unit that generates a driving force for the above-mentioned movement.

[0058] With the above-described configuration, the horizontal movement mechanism 150 can move the entire optical assembly 140 having the light receiving and emitting unit 142 and the laser unit 143 horizontally along the linear guide 151 in the device depth direction (Y direction in the figure) that coincides with the radial direction of the stage 110.

[0059] The horizontal movement mechanism 150 described above can move the irradiation point of the light emitted from the light receiving and emitting unit 142 on the wafer W on the stage 110 horizontally in the device depth direction (Y direction in the figure) that coincides with the radial direction of the stage 110. Similarly, the horizontal movement mechanism 150 can move the irradiation point of the laser light emitted from the laser unit 143 on the wafer W on the stage 110 and the irradiation point on the stage 110 horizontally in the device depth direction (Y direction in the figure). Furthermore, the rotation mechanism 112 can move the irradiation point of the light emitted from the light receiving and emitting unit 142 on the wafer W on the stage 110 in a circumferential direction (θ direction) centered on the rotation axis of the rotation mechanism 112 which coincides with the rotation axis of the stage 110. Similarly, the rotation mechanism 112 can move the irradiation point of the laser light emitted from the laser unit 143 on the wafer W on the stage 110 and the irradiation point on the stage 110 in the circumferential direction (θ direction). In other words, the horizontal movement mechanism 150 and the rotation mechanism 112 are Irradiation point of the light emitted from the light receiving / emitting unit 142 on the wafer W on the stage 110 Irradiation point of the laser light emitted from the laser unit 143 on the wafer W on the stage 110 Irradiation point of the laser light emitted from the laser unit 143 on the stage 110 It functions as a moving mechanism to move the

[0060] A cooling fan 160 for cooling the optical assembly 140 is provided above the chamber 100. The cooling fan 160 is particularly effective when the stage 110 is heated by a heater.

[0061] In addition, a cover may be provided in the optical path of the light receiving / emitting unit 142 and the laser unit 143.

[0062] <Control unit 70> FIG. 3 is a functional block diagram of the control unit 70 related to film thickness measurement. As shown in FIG. 3, the control unit 70 is realized by a processor such as a CPU reading and executing a program stored in a storage unit, and includes a movement control unit 71, a film thickness estimation unit 72, a direction control unit 73, a distance estimation unit 74, and a height control unit 75 as an adjustment mechanism.

[0063] The movement control unit 71 controls the horizontal movement mechanism 150 and the rotation mechanism 112 (specifically, controls the drive units 153 and 113) to control the movement of the irradiation point as described below. Irradiation point of the light emitted from the light receiving / emitting unit 142 on the wafer W on the stage 110 Irradiation point of the laser light emitted from the laser unit 143 on the wafer W on the stage 110 Irradiation point of the laser light emitted from the laser unit 143 on the stage 110

[0064] The movement control unit 71 can move the irradiation point to a film thickness measurement point. The origin of the R direction position of the irradiation point (specifically, the radial position of the stage 110) is, for example, the center of the stage 110. The origin of the θ direction position of the irradiation point (specifically, the rotational position of the stage 110) is the rotational position of the stage 110 when the wafer W is placed on it. For example, the origin of the θ direction position (θ coordinate) of the irradiation point is the rotational position of the stage when the stage 110 is rotated so that the wafer W is oriented in a predetermined direction after the wafer W is placed on the stage 110. The film thickness measurement points may be multiple, for example, and more specifically, may be 13 points in total, including one point at the center of the wafer W and four points in each of three annular regions obtained by radially dividing the outer peripheral region of the wafer W excluding the central region into thirds.

[0065] The film thickness estimation unit 72 estimates the thickness of the film formed on the wafer W based on the light receiving result at the light receiving unit of the light L1 emitted from the light receiving and emitting unit 142 and reflected by the wafer W on the stage 110. The film thickness estimation unit 72 estimates the film thickness for each film thickness measurement point.

[0066] The method for estimating the film thickness based on the result of receiving the reflected light can be, for example, a spectroscopic interference method. By using broad light with a short wavelength of about 800 nm or less as the light L1 for measuring the film thickness and using a spectroscopic interference method for estimating the film thickness, it is possible to measure the film thickness of an extremely thin film with a thickness of 10 nm or less, or even 1 nm or less. The method for estimating the film thickness based on the result of receiving the reflected light can also be an ellipsometry method.

[0067] The orientation control unit 73 controls the rotation mechanism 112 based on the detection result of the orientation of the stage 110 by the absolute encoder 115, and controls and adjusts the orientation of the stage 110 when the wafer W is placed on it (hereinafter, sometimes referred to as the "stage orientation when placed"). 3 This is the orientation of the stage 110 when the wafer W is placed on the stage 110.

[0068] In the film thickness measuring apparatus 60, the inclination of the stage 110 (specifically, the inclination of the wafer mounting surface with respect to the horizontal plane) cannot be set to 0° even if adjustment is made during assembly of the film thickness measuring apparatus 60. Conventionally, the orientation (rotation angle) of the stage 110 when the wafer W is mounted on the stage 110 has not been managed, and therefore the orientation of the stage 110 during film thickness measurement may differ for each wafer W. Specifically, the orientation of the stage 110 at each film thickness measurement point may differ for each wafer W. In this way, if the orientation of the stage 110 at each film thickness measurement point differs for each wafer W, the inclination of the stage 110 at each film thickness measurement point also differs for each wafer W. For example, as shown in Fig. 4, when the stage 110 is inclined in the negative direction with respect to the horizontal plane in a front view at the film thickness measurement point A (i.e., when the inclination angle α>0), when the orientation of the stage 110 changes by 180°, the stage 110 is inclined in the positive direction with respect to the horizontal plane in a front view at the same film thickness measurement point A (i.e., the inclination angle α<0) as shown in Fig. 5. Note that the symbol N in Figs. 4 and 5 indicates a notch. As described above, when the inclination of the stage 110 differs for each wafer W at each film thickness measurement point, the inclination of the wafer W on the stage 110 also differs, and therefore the light receiving results of the reflected light by the light receiving and emitting unit 142 (specifically, the light intensity) also differ.

[0069] In particular, the optical axis AX of the light receiving part of the light receiving / emitting unit 142 (specifically, the optical axis of the light collecting optical system for the light receiving sensor) is also installed tilted from the vertical direction even if adjustment is made during assembly or the like. In this manner, when the optical axis of the light receiving part of the light receiving / emitting unit 142 is tilted, the ease with which the reflected light hits the light receiving part of the light receiving / emitting unit 142 varies greatly depending on the orientation of the stage 110. For example, as shown in Figs. 4 and 5, when the optical axis AX of the light receiving part of the light receiving / emitting unit 142 is tilted in the positive direction with respect to the vertical axis in front view, if the stage 110 is tilted in the positive direction with respect to the horizontal plane, the reflected light is likely to hit the light receiving part of the light receiving / emitting unit 142, but if the orientation of the stage 110 is different and the stage 110 is tilted in the negative direction with respect to the horizontal plane, the reflected light is unlikely to hit the light receiving part of the light receiving / emitting unit 142.

[0070] According to repeated experiments by the inventors, it was found that the difference in the light receiving results of the reflected light by the light receiving and emitting unit 142 caused by the inclination of the stage 110 affects the measurement accuracy in the film thickness measurement of an extremely thin film of 10 nm or less, or even 1 nm or less. For example, even for wafers W on which a film is formed using the same processing recipe, the measurement results of the film thickness at the center of the wafer differed greatly by about 0.1 nm between wafers W simply by changing the stage orientation by 120° when the wafers were placed. Also, the film thickness distribution shape differed greatly between wafers W.

[0071] Therefore, in this embodiment, the orientation control unit 73 controls the rotation mechanism 112 based on the detection result of the orientation of the stage 110 by the absolute encoder 115 so that the stage orientation when placed is in a desired orientation.

[0072] For example, in cases where the orientation of the wafer W when placed on the stage 110 (hereinafter sometimes referred to as the "wafer orientation when placed") is constant, the orientation control unit 73 controls the rotation mechanism 112 so that the stage orientation when placed becomes a predetermined reference orientation.

[0073] If the wafer orientation at the time of placement is constant, the stage orientation at the time of placement can be set to a predetermined reference orientation, so that the relative orientation of the stage 110 with respect to the wafer W to be placed when the wafer W is placed (hereinafter, sometimes referred to as the "relative stage orientation at the time of placement") is also constant. However, in the following cases, the wafer orientation at the time of placement may not be constant. That is, when the film formation system 1 processes multiple wafers W continuously using the processing device 40 as in this embodiment, and the film thickness measurement device 60 measures each of the multiple wafers W, the wafer orientation at the time of placement may differ between the multiple wafers W even if the process performed immediately before the measurement is common between the wafers W. Also, when the film formation system 1 performs multiple processes using the processing device 40 as in this embodiment to form a laminated film on the wafer W, and the film thickness measurement device 60 performs measurement after each of the multiple processes, the wafer orientation at the time of placement may differ between the multiple processes.

[0074] In order to keep the relative stage orientation constant when the wafer is placed even when the wafer orientation is not constant as described above, the orientation control unit 73 may control the rotation mechanism 112 so that the relative stage orientation when the wafer is placed is in a predetermined orientation. In this case, the information on the orientation of the wafer when it is placed may be obtained by providing a wafer orientation detection unit (not shown) in the processing station 11 and applying the detection result of the detection unit. In addition, if the orientation of the wafer when it is placed is known, the information on the orientation may be stored in advance in the storage unit of the control unit 70.

[0075] According to experiments conducted by the inventors, by adjusting the stage orientation when placing the wafer as described above, for wafers W on which films are formed using the same processing recipe, the variation in the measurement results of the film thickness at the center of the wafer can be suppressed to 0.01 nm or less, and the film thickness distribution shape can be made similar between wafers W.

[0076] Returning to the explanation of Figure 3. The distance estimation unit 74 estimates the relative working distance d based on the result of reception at the laser receiving unit of the laser L2 emitted from the laser unit 143 and reflected by the wafer W on the stage 110. The distance estimation unit 74 estimates the relative working distance d for each film thickness measurement point. Further, the distance estimation section 74 can estimate the distance from the laser unit 143 to the stage 110 based on the result of reception by the laser receiving section of the laser light L2 emitted from the laser unit 143 and reflected by the stage 110.

[0077] Based on the result of the estimation of the relative working distance d by the distance estimating unit 74, the height control unit 75 controls the lifting mechanism 117, controls the height of the stage 110, and adjusts the relative working distance d during film thickness measurement.

[0078] If the relative working distance d is not adjusted, and the stage 110 is tilted with respect to the horizontal plane, the relative working distance d will differ for each film thickness measurement position. Through repeated experiments, the inventors have found that differences in the relative working distance d affect the measurement accuracy when measuring extremely thin films of less than 10 nm, or even less than 1 nm. For example, a change of 1 mm in the relative working distance d can cause an error of 0.2 nm in the measured film thickness.

[0079] Therefore, in this embodiment, the height control unit 75 controls the lifting mechanism 117 based on the estimation result of the relative working distance d by the distance estimation unit 74 so that the relative working distance d during film thickness measurement becomes a desired distance.

[0080] For example, the height control unit 75 controls the lifting mechanism 117 so that the relative working distance d during film thickness measurement is corrected to a predetermined distance for each film thickness measurement point.

[0081] In addition, the height control unit 75 may control the lifting mechanism 117 so that the relative working distance d is not corrected for one film thickness measurement point, but the relative working distance d at another film thickness measurement point is corrected to be the same as the relative working distance d at the one film thickness measurement point.

[0082] When stage 110 is tilted with respect to the horizontal plane, the film thickness can be measured more accurately at each film thickness measurement point by correcting the relative working distance d in addition to adjusting the stage orientation when placed as described above. According to the experiments of the present inventors, by adjusting both the stage orientation when the film was placed and the relative working distance d, a film thickness distribution closer to the in-plane distribution of the film thickness measured by X-ray fluorescence analysis was obtained compared to the case where only the stage orientation when the film was placed was adjusted. Note that although X-ray fluorescence analysis can measure film thickness accurately, it is not suitable for in-situ film thickness measurement because it uses X-rays.

[0083] <Teaching the origin position> Next, a description will be given of teaching of the reference orientation (origin position) of the stage 110, which is performed prior to film thickness measurement using the film thickness measuring device 60. Fig. 6 is a flowchart for explaining an example of a method for teaching the reference orientation of the stage 110. Note that the above teaching is performed when the film formation system 1 and the film thickness measuring device 60 are started up.

[0084] For example, first, after the stage 110 is installed, the height distribution of the stage 110 is acquired under the control of the control unit 70, and the acquired height distribution is evaluated by an operator (step S1).

[0085] Specifically, for example, after film thickness measuring device 60 is assembled, the following processes are performed for each of the multiple height measuring positions. The movement control unit 71 controls the horizontal movement mechanism 150 and the rotation mechanism 112 so that the irradiation point of the laser light emitted from the laser unit 143 on the stage 110 coincides with the height measurement position, thereby moving the laser unit 143 and rotating the stage 110. After that, the control unit 70 controls the laser light source unit 146 to irradiate the laser light from the laser unit 143 toward the stage 110, and causes the laser receiving unit to detect the reflected light from the irradiation point of the laser light on the stage 110. The distance estimation unit 74 estimates the distance from the laser unit 143 to the stage 110, which corresponds to the height of the stage 110, based on the detection result from the laser receiving unit.

[0086] Next, the control unit 70 causes the distance from the laser unit 143 to the stage 110 estimated for each of the multiple height measurement positions to be displayed as a height distribution of the stage 110 on, for example, a display device (not shown). The operator evaluates the height distribution of the stage 110 based on, for example, the contents displayed on the display device.

[0087] When the operator determines the tilt direction of stage 110 from the height distribution of stage 110 (step S2), the operator rotates stage 110 around support shaft 111 according to the determined tilt direction of stage 110 (step S3). Note that step S3 may be omitted.

[0088] Then, in response to an operator's operation of an operation input unit (not shown) of the control unit 70, the control unit 70 stores the detection result by the absolute encoder 115 in this state in a memory unit (not shown) as the origin position of the rotation angle of the stage 110, i.e., the reference orientation (of the stage 110) (step S4). This completes the teaching of the reference orientation of the stage 110.

[0089] <Film thickness measurement method> Next, a description will be given of a film thickness measuring method using the film thickness measuring apparatus 60. FIG 7 is a flowchart for explaining an example of a film thickness measuring method using the film thickness measuring apparatus 60.

[0090] First, the orientation control unit 73 controls the rotation mechanism 112 based on the detection result of the orientation of the stage 110 by the absolute encoder 115, and adjusts the rotation angle of the stage 110 to the origin position stored in the memory unit, in other words, adjusts the orientation of the stage 110 to the reference orientation stored in the memory unit (step S11).

[0091] Next, the orientation control unit 73 controls the rotation mechanism 112 based on the detection result of the orientation of the stage 110 by the absolute encoder 115 and information on the orientation of the wafer W when the wafer W is placed on the stage 110, and rotates the stage 110 so that the relative stage orientation when placed is a predetermined orientation (step S12). Note that it is not necessary to always make the relative stage orientation when placed be a predetermined orientation, and this step S12 may be omitted.

[0092] Next, under the control of the control unit 70, the gate valve G21 is opened, and the wafer transfer mechanism 50 3 The wafer W is carried into the chamber 100 and placed on the stage 110 (step S13). At this time, the stage orientation when placed is a reference orientation, or the relative stage orientation when placed is a predetermined orientation. After the wafer W is placed, the gate valve G21 is closed.

[0093] Next, for example, the center position of the wafer is set as the film thickness measurement position, and the relative working distance d and the film thickness at the center position of the wafer are measured (step S14).

[0094] For example, first, the control unit 70 controls the rotation mechanism 112 to rotate the stage 110 so that the orientation of the wafer W on the stage 110 is in a predetermined orientation. For this purpose, the film thickness measuring device 60 may be provided with a mechanism for detecting the orientation of the wafer W. Furthermore, the height control unit 75 controls the lifting mechanism 117 to raise the stage 110 so that the height of the stage 110 reaches a predetermined measurement height. Next, the movement control unit 71 controls the horizontal movement mechanism 150 and the rotation mechanism 112 so that the irradiation point of the laser light emitted from the laser unit 143 on the wafer W on the stage 110 coincides with the center position of the wafer, thereby moving the laser unit 143 and rotating the stage 110.

[0095] Thereafter, the control unit 70 controls the laser light source unit 146 to irradiate laser light from the laser unit 143 toward the wafer W on the stage 110, and causes the laser receiving unit to detect reflected light from the irradiation point of the laser light on the wafer W on the stage 110. Then, the distance estimation unit 74 estimates the relative working distance d at the center position of the wafer based on the detection result at the laser receiving unit.

[0096] Furthermore, the control unit 70 controls the horizontal movement mechanism 150 to move the light receiving and emitting unit 142 so that the irradiation point of the light emitted from the light receiving and emitting unit 142 on the wafer W on the stage 110 coincides with the center position of the wafer. Thereafter, the control unit 70 controls the light source unit 144 to irradiate light from the light receiving / emitting unit 142 toward the wafer W on the stage 110, and causes the light receiving unit of the light receiving / emitting unit 142 to detect reflected light from the irradiation point of the light on the wafer W on the stage 110. Then, the film thickness estimating section 72 estimates the film thickness at the center position of the wafer based on the detection result at the light receiving section of the light receiving / emitting unit 142 .

[0097] Next, for each of the remaining film thickness measurement positions, the relative working distance d is corrected to be the same as that at the wafer center position, and the film thickness after the correction is measured (step S15).

[0098] Specifically, for example, the following processes are performed for each of the remaining film thickness measurement positions. The movement control unit 71 controls at least one of the horizontal movement mechanism 150 and the rotation mechanism 112 so that the irradiation point of the laser light emitted from the laser unit 143 on the wafer W on the stage 110 coincides with the film thickness measurement position, and causes either the laser unit 143 to move or the stage 110 to rotate. Thereafter, the control unit 70 controls the laser light source unit 146 to irradiate laser light from the laser unit 143 toward the wafer W on the stage 110, and causes the laser receiving unit to detect reflected light from the irradiation point of the laser light on the wafer W on the stage 110. The distance estimation unit 74 then estimates the relative working distance d at the film thickness measurement position based on the detection result at the laser receiving unit. Next, the height control unit 75 controls the lifting mechanism 117 based on the estimation result of the distance estimation unit 74, and corrects the height of the stage 110 so that the relative working distance d at the film thickness measurement position becomes the same as the relative working distance d at the wafer center position. After the correction, the movement control unit 71 controls the horizontal movement mechanism 150 to move the light receiving and emitting unit 142 so that the irradiation point of the light emitted from the light receiving and emitting unit 142 on the wafer W on the stage 110 coincides with the film thickness measurement position. Thereafter, the control unit 70 controls the light source unit 144 to irradiate light from the light receiving and emitting unit 142 towards the wafer W on the stage 110, and causes the light receiving unit of the light receiving and emitting unit 142 to detect reflected light from the irradiation point of the light on the wafer W on the stage 110. Then, the film thickness estimating section 72 estimates the film thickness at the film thickness measurement position based on the detection result at the light receiving section of the light receiving / emitting unit 142.

[0099] When the film thickness measurement at all film thickness measurement positions is completed, the orientation control unit 73 controls the rotation mechanism 112 based on the detection result of the orientation of the stage 110 by the absolute encoder 115, so that the orientation of the wafer W when unloaded is set to a predetermined orientation (step S16). For this purpose, a mechanism for detecting the orientation of the wafer W may be provided in the film thickness measurement device 60. Also, step S16 may be omitted. Note that even if the wafer W has the same stage orientation when placed, the orientation of the wafer W when unloaded may be changed depending on the processing device to which the wafer W is to be transported after measurement.

[0100] Thereafter, under the control of the control unit 70, the gate valve G21 is opened, and the wafer transfer mechanism 50 3 The wafer W is then removed from the chamber 100 (step S17). After the wafer W is removed, the gate valve G21 is closed. Then, steps S11 to S17 are performed on the next wafer W.

[0101] <Effects> As described above, in this embodiment, the orientation control unit 73 controls the rotation mechanism 112 so that the stage orientation when placed is set to a desired orientation. Therefore, in measuring the thickness of an extremely thin film, such as 10 nm or less, or even 1 nm or less, it is possible to suppress variation in the measurement results of the thickness of the wafer W on the stage 110 for each wafer W, which is caused by the stage 110 being tilted.

[0102] In this embodiment, the height control unit 75 controls the lifting mechanism 117 so that the relative working distance d during film thickness measurement becomes a desired distance. Therefore, in film thickness measurement of an extremely thin film, such as 0 nm or less, or even 1 nm or less, even if the stage 110 is tilted, the film thickness can be measured with high accuracy at each film thickness measurement point.

[0103] The aforementioned Patent Documents 2 and 3 disclose a technique for measuring film thickness in-situ by connecting a module for measuring film thickness in a film formation system having multiple processing modules. However, these techniques use a laser to measure film thickness, and are not intended for measuring extremely thin films of 10 nm or less, or even 1 nm or less, such as those used in MRAM. Conventionally, film thickness measurements for MRAM films have been performed by inserting a wafer after forming a laminated film into the film formation system. This had to be done after the equipment was removed from the building. In contrast, according to this embodiment, film thickness measurement of extremely thin films of 10 nm or less, or even 1 nm or less, can be performed in situ without removing the film from the film formation system.

[0104] In this embodiment, the orientation control unit 73 may control the rotation mechanism 112 so that the relative stage orientation at the time of placement becomes a predetermined orientation. In this way, when the film formation system 1 continuously processes a plurality of wafers W using the processing device 40 and the film thickness measurement device 60 measures each of the plurality of wafers W, the relative stage orientation at the time of placement can be made the same for the plurality of wafers W. Therefore, based on the measurement results by the film thickness measurement device 60, the processing results for each wafer W by the film formation system 1 can be appropriately evaluated.

[0105] The orientation control unit 73 controls the rotation mechanism 112 so that the relative stage orientation at the time of placement becomes a predetermined orientation, which has the following effect. That is, when the film formation system 1 performs a plurality of processes using the processing device 40 to form a laminated film on the wafer W, and the film thickness measurement device 60 performs measurement after each of the plurality of processes, the relative stage orientation at the time of placement can be made the same between the plurality of processes. Therefore, based on the measurement result by the film thickness measurement device 60, the processing result of the wafer W by the film formation system 1 can be appropriately evaluated for each process related to the formation of a laminated film.

[0106] <Modification> In the above example, the absolute encoder 115 is used to detect the orientation of the stage 110, but anything other than the absolute encoder 115 may be used as long as it is possible to detect the orientation of the stage 110, ie, the absolute rotation angle of the stage 110.

[0107] In the above example, the film thickness measuring device is provided as a module separate from the vacuum transfer chamber 31 and the processing device 40. However, for example, the film thickness measuring device may be integrated into the vacuum transfer chamber 31 as a module. In the above example, the optical assembly 140 is configured to be movable in the depth direction of the apparatus. Alternatively, or in addition, the stage 110 may be configured to be movable in the depth direction of the apparatus.

[0108] Furthermore, in the above example, the movement mechanism for moving each irradiation point includes the rotation mechanism 112, but the movement of each irradiation point may be performed by a movement mechanism that does not include the rotation mechanism 112, such as an XY stage.

[0109] In the above example, the adjustment of the relative working distance d during film thickness measurement is performed using the lifting mechanism 117 that raises and lowers the stage 110. However, a lifting mechanism may be provided in the optical assembly 140, and the relative working distance d during film thickness measurement may be adjusted using the lifting mechanism.

[0110] The embodiments disclosed herein should be considered as illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0111] 1. Film deposition system 30 Vacuum transport device 40 Processing equipment 60 Film Thickness Measuring Device 70 Control section 100 Chamber 112 Rotation mechanism 115 Absolute Encoder 142 Transmitting and receiving unit L1 light W wafer

Claims

1. A film thickness measuring device for measuring the thickness of a film formed on a substrate, a mounting table on which a substrate is placed; a light receiving and emitting unit that emits light for film thickness measurement to the substrate on the mounting table and receives light of the emitted light reflected by the substrate on the mounting table; a rotation mechanism that rotates the mounting table; An orientation detection unit that detects an orientation of the mounting table; A control unit, the control unit controls the rotation mechanism based on a detection result by the orientation detection unit so that an orientation of the placement table with respect to the light receiving and emitting unit when a substrate is placed on the placement table becomes a predetermined reference orientation; a distance measuring unit that measures a distance from the light receiving and emitting unit to an irradiation point of the light of the light receiving and emitting unit on the substrate placed on the mounting table; and an adjustment mechanism for adjusting a distance from the light receiving and emitting unit to the irradiation point, The control unit further controls the adjustment mechanism based on a measurement result by the distance measuring unit.

2. The film thickness measuring device according to claim 1 , wherein the control unit controls the adjustment mechanism based on a measurement result by the distance measuring unit so that the distance from the light receiving and emitting unit to the irradiation point during film thickness measurement becomes a desired distance.

3. A processing apparatus for forming a film on a substrate; A transport device that transports the substrate; a film thickness measuring device for measuring the thickness of a film formed on a substrate, The film thickness measuring device is a mounting table on which a substrate is placed; a light receiving and emitting unit that emits light for film thickness measurement to the substrate on the mounting table and receives light of the emitted light reflected by the substrate on the mounting table; a rotation mechanism for rotating the mounting table; An orientation detection unit that detects an orientation of the mounting table; A control unit, the control unit controls the rotation mechanism based on a detection result by the orientation detection unit so that an orientation of the placement table with respect to the light receiving and emitting unit when a substrate is placed on the placement table becomes a predetermined reference orientation; The film thickness measuring device is a distance measuring unit that measures a distance from the light receiving and emitting unit to an irradiation point of the light of the light receiving and emitting unit on the substrate placed on the mounting table; An adjustment mechanism for adjusting a distance from the light receiving and emitting unit to the irradiation point, The control unit further controls the adjustment mechanism based on the measurement result by the distance measuring unit so that the distance from the light receiving and emitting unit to the irradiation point during film thickness measurement becomes a desired distance.

4. A method for measuring the thickness of a film formed on a substrate by a film thickness measuring device, comprising the steps of: The film thickness measuring device is a mounting table on which a substrate is placed; a light receiving and emitting unit that emits light for film thickness measurement to the substrate on the mounting table and receives light of the emitted light reflected by the substrate on the mounting table, detecting an orientation of the mounting table when the substrate is mounted on the mounting table; rotating the mounting table so that the orientation of the mounting table with respect to the light receiving and emitting unit when the substrate is placed thereon is a predetermined reference orientation based on a detection result of the orientation of the mounting table; placing a substrate on the stage in the predetermined reference orientation; a step of emitting the light from the light receiving and emitting unit, and measuring a thickness of the film formed on the substrate on the mounting table based on a result of receiving the reflected light by the light receiving and emitting unit; measuring a distance from the light receiving and emitting unit to an irradiation point of the light from the light receiving and emitting unit on the substrate on the mounting table; and adjusting the distance from the light emitting and receiving unit to the irradiation point during the step of measuring the thickness of the film based on the measurement results from the step of measuring the distance.

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