JP2003097919A - Device for measuring thickness of film and system for processing substrate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to measure the thickness of film even in the case that a film, the object to be measured is not in a stationary state, or treatment liquid exists on the surface of the film, the object to be measured. SOLUTION: Light from an optical fiber for projecting light 51 is reflected by a half mirror 73 and guided to the surface of a wafer W. Reflecting light from the surface of the wafer W passes through an achromatic lens 72 and the half mirror 73, is reflected by a totally reflective mirror 74, is diffused and unformed by a diffuser 75 and enters an optical fiber for receiving light 54. Therefore, the light with stable intensity can enter the optical fiber for receiving light 54 even in the case the wafer W is rotating, or the treatment liquid exists on the surface of the wafer W.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film thickness measuring device, and specifically, for example, a semiconductor wafer, a glass substrate for a liquid crystal display panel, a glass substrate for a plasma display panel, an optical disc substrate, a magneto-optical disc substrate. ,
The present invention relates to an apparatus for measuring the film thickness of a film formed on the surface of various substrates to be processed such as a magnetic disk substrate and a photomask substrate. The present invention also relates to a substrate processing apparatus equipped with a film thickness measuring device.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductor devices, liquid crystal display panels, etc., a process of reducing the film thickness of a thin film to a desired value by etching the thin film formed on the surface of a substrate with an etching solution such as hydrofluoric acid. May occur. In order to control the film thickness, it is essential to measure the film thickness. Therefore, when the etching liquid is supplied to the substrate surface in the processing chamber of the substrate processing apparatus to etch the thin film on the substrate surface, for example, the etching process is interrupted after a certain period of time, and the substrate is taken out from the processing chamber. Be done. The film thickness of the thin film on the substrate surface is measured by a film thickness measuring device provided separately from another chamber or the substrate processing apparatus.

Based on this, the etching conditions are set, the substrate is again carried into the processing chamber of the substrate processing apparatus, and the etching process is restarted. Thus, the thin film is etched to a desired film thickness.

[0004]

However, in such a process, the etching process must be interrupted, and
Since it is necessary to move the substrate into and out of the processing chamber and the film thickness measuring device during the processing, the processing step requires a remarkably long time, resulting in poor productivity. The above problem does not occur if the film thickness can be measured in parallel when the substrate is treated with the etching solution. However, the conventional film thickness measuring device has a film thickness of a dry thin film on a stationary substrate. Since it is designed to measure thickness, film thickness cannot be measured during processing.

That is, in the processing chamber, the substrate is held substantially horizontal by the spin chuck and is rotated at a high speed, and the etching liquid is supplied to the substrate surface in this state.
Therefore, the surface of the substrate is wet with the etching liquid, and the etching liquid is in a complicatedly wavy state due to the centrifugal force and the Coriolis force as shown in FIG. Moreover, since the spin chuck usually has an inclination of about 0.3 mm due to the mechanical assembling accuracy and the accuracy of parts, the substrate does not rotate stably in a certain horizontal plane, It is accompanied by a precession movement as shown in FIG.

On the other hand, the film thickness measuring device has a film thickness optical system in which an achromatic lens, a half mirror and a total reflection mirror are arranged in order from the substrate surface. Then, a certain amount of light is projected from the projector to the half mirror through the projecting optical fiber, and the reflected light from the total reflection mirror is guided to the receiver through the receiving optical fiber. That is, the light reflected by the half mirror is directed to the substrate surface, the light reflected by the film on the substrate surface passes through the achromatic lens and the half mirror, is reflected by the total reflection mirror, and is incident on the receiving end of the receiving optical fiber. Be led to.

Therefore, when the substrate is rotated or the treatment liquid (especially the treatment liquid in a wavy state) is present on the substrate surface, the reflected light from the substrate surface is incident on the incident end of the light receiving optical fiber. As a result, the film thickness cannot be measured. Therefore, an object of the present invention is to solve the above-mentioned technical problems and to provide a film thickness measuring device capable of measuring the film thickness of a film to be measured even when the film to be measured is not stationary.

Another object of the present invention is to provide a film thickness measuring device capable of measuring the film thickness even when the treatment liquid is present on the surface of the film to be measured. Still another object of the present invention is to provide a substrate processing apparatus which improves productivity by measuring the film thickness of the film on the surface of the substrate while the substrate is being moved or rotated. Still another object of the present invention is to provide a substrate processing apparatus with improved productivity by measuring the film thickness of the film on the surface of a substrate being processed with a processing liquid.

[0009]

Means for Solving the Problems and Effects of the Invention The invention according to claim 1 for achieving the above object comprises a light projecting portion (52, 53) for irradiating a film to be measured with light. A light receiving part (54, 5) for receiving the reflected light from the film to be measured.
5) and a diffuser (75) which is interposed in the light receiving path from the film to be measured to the light receiving section and which diffuses and uniformizes the reflected light from the film to be measured and emits it toward the light receiving section. Is a film thickness measuring device (50). The alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies in this section below.

According to this structure, since the reflected light from the film to be measured is diffused and made uniform by the diffuser, the surface of the film to be measured is moving, or the film to be measured is transferred from the film to be measured to the light receiving portion. Even when the light receiving path to reach is unstable, stable light can be made incident on the light receiving portion. This allows measurement of film thickness even if the film to be measured is moving or rotating, or if there is an unstable (eg, wavy) liquid layer on the film to be measured. Can be done well.

The invention according to claim 2 is the film thickness measuring apparatus according to claim 1, characterized in that the diffuser is arranged immediately before the light receiving portion in the light receiving path. With this configuration, it is possible to reliably enter the diffused and uniformized stable light into the light receiving portion. According to a third aspect of the present invention, there is provided a substrate processing apparatus for processing a substrate having a film formed on its surface, the substrate holding mechanism (3) holding the substrate.
1), a driving mechanism (35) for moving or rotating the substrate holding mechanism, and a film thickness of a film on the surface of the substrate held by the substrate holding mechanism being moved or rotated by the driving mechanism. A substrate processing apparatus comprising the film thickness measuring apparatus (50) according to claim 1 or 2.

With this configuration, the film thickness of the film on the surface of the substrate is measured while the substrate is being held by the substrate holding mechanism and is being moved or rotated. Therefore, film thickness measurement can be performed in parallel during substrate transfer or substrate processing.
The productivity of the substrate processing apparatus can be improved. The invention according to claim 4 further comprises a processing liquid supply mechanism (40 to 49) for supplying a processing liquid to the substrate held by the substrate holding mechanism. is there.

According to this structure, the film thickness can be measured during the movement or rotation of the substrate in the substrate processing apparatus for processing the substrate with the processing liquid. In the invention according to claim 5, the processing liquid supply mechanism supplies the processing liquid to the substrate held by the substrate holding mechanism while the substrate holding mechanism is moved or rotated by the driving mechanism. The substrate processing apparatus according to claim 4, wherein

According to this structure, the processing liquid is supplied to the substrate while the substrate holding mechanism holding the substrate is moved or rotated. Since the film thickness measuring device can measure the film thickness satisfactorily even if the unstable processing liquid exists on the substrate, it is possible to simultaneously measure the film thickness while performing the processing with the processing liquid on the substrate. . The invention according to claim 6 is a substrate processing apparatus for processing a substrate having a film formed on a surface thereof, comprising a processing liquid supply mechanism (40 to 49) for supplying a processing liquid to the substrate, and the processing liquid. A substrate processing apparatus, comprising: the film thickness measuring device (50) according to claim 1 or 2 for measuring a film thickness of a film on a surface of a substrate to which a processing liquid is supplied by a supply mechanism. .

According to the present invention, the film thickness is measured in parallel while the substrate is being treated with the treatment liquid. Thereby, the productivity of the substrate processing apparatus can be improved. The processing liquid may be an etching liquid, and based on the output of the film thickness measuring device, the etching liquid is supplied / distributed.
By controlling the stop, the film may be etched to a desired film thickness.

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic plan view for explaining a layout of a substrate processing apparatus according to an embodiment of the present invention. This substrate processing apparatus etches a thin film formed on the surface of a semiconductor wafer (hereinafter, simply referred to as “wafer”) W, which is an example of a substrate, to the middle of the film thickness to form a thin film having a predetermined film thickness on the wafer. It is an etching processing apparatus for leaving it on the surface of W. This substrate processing apparatus includes a cassette mounting unit 1 in which a plurality of cassettes C for storing unprocessed wafers W and processed wafers W are arranged along a predetermined direction, and an etching process for each wafer W. A plurality of processing units 21 and
2, 23, and 24 are provided. Multiple processing units 21 to 2
4 are arranged along both sides of the straight conveying path 27,
A linear transfer path 27 is provided with a main transfer robot 25 that can reciprocate along the linear transfer path 27. In addition, an indexer robot 11 that is movable in the alignment direction of the cassettes C is provided in the vicinity of the cassette placing unit 1, and the indexer robot 11 transfers the wafer W to and from the main transfer robot 25. It can be carried out.

The unprocessed wafers W are taken out one by one from the cassette C by the indexer robot 11 and transferred to the main transfer robot 25. Main transport robot 25
Loads an unprocessed wafer W into any of the processing units 21 to 24. On the other hand, the wafer W that has been processed by the processing units 21 to 24 is unloaded by the main transfer robot 25, transferred to the indexer robot 11, and then accommodated in the cassette C placed on the cassette placing unit 1. It When the processing of the wafer W is completed in any of the processing units 21 to 24, the main transfer robot 25 actually takes out the processed wafer W from the processing unit, and then unprocesses the processed wafer W. It operates so as to carry in the wafer W.

FIG. 2 is an illustrative view showing a common configuration of the processing units 21 to 24. A spin chuck 31 that holds the wafer W substantially horizontally and rotates about a vertical axis is provided in the processing chamber 20. In the processing chamber 20, above the spin chuck 31, a nozzle 40 for supplying a processing liquid (etching liquid or pure water) to the surface of the wafer W held by the spin chuck 31 and a surface of the wafer W are provided. Film thickness optical system 5 for measuring the film thickness of a thin film
1 and are arranged. The spin chuck 31 is housed in a cylindrical processing cup 32 having a bottom and provided in the processing chamber 20, and the processing liquid after being used for processing the wafer W is processed at the bottom of the processing cup 32. Chamber 20
A drainage port 33 is formed to guide the liquid to the outside.

Below the processing chamber 20, there is provided a rotary drive mechanism 35 for applying a rotary drive force to the rotary shaft 34 of the spin chuck 31. The etching liquid (for example, buffered hydrofluoric acid (BHF)) stored in the chemical liquid tank 41 or pure water from the pure water supply source 42 can be selectively supplied to the nozzle 40 above the spin chuck 31. More specifically, the etching liquid in the chemical liquid tank 41 is pumped out by the pump 43, and the chemical liquid supply passage 44
Through the three-way valves 45 and 46, and further through the processing liquid supply path 47
Can be supplied to the nozzle 40 via. In addition, the pure water supply source 4
Pure water from 2 can be supplied to the nozzle 40 from the pure water supply passage 48, the three-way valve 46, and the treatment liquid supply passage 47.
The chemical liquid circulation path 4 is provided between the chemical liquid tank 41 and the three-way valve 45.
9 is provided. The pump 43 is always driven, and when the etching solution is not supplied to the nozzle 40, the etching solution delivered by the pump 43 is
The liquid medicine tank 41 is circulated through the circulation path 49.

A drainage pipe 33 is connected to the drainage port 33 formed in the processing cup 32. This drainage pipe 36
Is connected via a three-way valve 37 to a recovery pipe 38 directed to the chemical liquid tank 41 and a waste liquid pipe 39. When the pure water is discharged from the nozzle 40, the three-way valve 37 connects the drainage pipe 36 to the wastewater pipe 39 to drain the pure water after being used for the treatment. On the other hand, when the etching liquid is supplied from the nozzle 40, the three-way valve 37 is controlled so as to connect the drainage pipe 36 to the recovery pipe 38.
As a result, the etching liquid can be collected in the chemical liquid tank 41, so that the consumption of the etching liquid can be suppressed.

In order to control the three-way valves 37, 45, 46 and the rotary drive mechanism 35, a control section 60 including a microcomputer is provided. The control unit 60 controls the three-way valves 37, 45, 46 and the like based on the output signal of the film thickness measuring device 50 including the film thickness optical system 51. The film thickness measuring device 50 includes the above-described film thickness optical system 51, a projector 53 coupled to the film thickness optical system 51 via a light projecting optical fiber 52, and a light receiving device for the film thickness optical system 51. And a spectroscope 55 coupled via an optical fiber 54. The light projector 53 generates a certain amount of light. This light is emitted from the film thickness optical system 51 toward the surface of the wafer W held by the spin chuck 31. On the other hand, the reflected light from the wafer W passes through the film-thickness optical system 51 and is received by the light-receiving optical fiber 5.
4 to the spectroscope 55. The output signal of the spectroscope 55 is input to the control unit 60.

FIG. 3 is an illustrative view for explaining the structure of the film thickness optical system 51. In the film thickness optical system 51, a light projecting / receiving window member 71, an achromatic lens 72, a half mirror 73 and a total reflection mirror 74 are arranged in order from the side closer to the spin chuck 31 along a substantially vertical direction, and further, a total reflection mirror 74. Diffuser 7 in the direction of reflected light from
5 are arranged. The half mirror 73 is almost 4 times larger than the wafer W held by the spin chuck 31.
It is provided in a posture of forming an angle of 5 degrees (that is, an angle of about 45 degrees with respect to the horizontal plane), and the horizontal direction (wafer W
Light from the emission end 52a of the light projecting optical fiber 52, and reflects the light vertically downward toward the surface of the wafer W held by the spin chuck 31. This light reaches the surface of the wafer W via the achromatic lens 72 and the light projecting / receiving window member 71.

The reflected light reflected by the thin film formed on the surface of the wafer W is transmitted / received by the window member 71.
The light is transmitted through the achromatic lens 72 and the half mirror 73 in order, and the diffuser 7 is transmitted by the total reflection mirror 74.
After being reflected toward 5, the light is diffused and uniformized by the diffuser 75 and is incident on the incident end 54a of the light receiving optical fiber 54. That is, the diffuser 75
Is the incident end 54a of the light receiving fiber 54 and the total reflection mirror 7
4, the incident end face 75a thereof faces the total reflection mirror 74, and the emitting end face 75b thereof faces the incident end 54a of the light receiving optical fiber 54.

The achromatic lens 72 is used for the wafer W.
It has a function of focusing the reflected light from the incident end face 75a of the diffuser 75. The light projecting / receiving window member 71 is made of, for example, a light projecting member having chemical resistance such as sapphire, and protects other components of the film thickness optical system from the etching solution. The light incident on the light receiving optical fiber 54 is
The spectroscope 55 receives the spectrum decomposition processing, and a signal representing the processing result is input to the control unit 60. The controller 60 determines the wafer W based on the input spectrum.
The film thickness of the thin film formed on the surface of is detected.

FIG. 4 is a perspective view for explaining the structure of the diffuser 75. The diffuser 75 is made of a transparent material such as glass and has a cylindrical shape with a diameter larger than that of the light receiving optical fiber 54. At least one of the incident end surface 75a and the exit end surface 75b is a rough surface that has been subjected to a rough surface treatment such as sandblasting, and its side surface, that is, the peripheral surface 75c is a polished polished surface. ing. That is, the diffuser 75
Has a basic form as a cylindrical optical glass, and by making either the incident end face 75a or the emitting end face 75b a rough surface, the light incident from the incident end face 75a is diffused and made uniform. The processed light is emitted from the emission end face 75b.

FIGS. 5A and 5B are views showing how light propagates inside the diffuser 75. In this Figure 5,
Incident end face 75a and exit end face 75 of diffuser 75
The case where roughening is applied to both b is shown. The light incident on the incident end face 75a is diffused by the diffuser effect of the incident end face 75a subjected to the rough surface treatment.
5 is spread inward. Of the diffused light, the light in the range of the angle A corresponding to the total internal reflection angle of the constituent material of the diffuser 75 is not attenuated and is emitted without being attenuated.
reach b. Then, the emitting end surface 75 subjected to the rough surface treatment
Of the light diffused by the diffusion effect of b, the light within the range of the angle φ determined by the numerical aperture NA of the light receiving optical fiber 54 is transmitted to the spectroscope 55 by the light receiving optical fiber 54.

As can be understood from the comparison of FIGS. 5 (a) and 5 (b),
Even if the reflected light from the wafer W is collected at any position on the incident end surface 75a of the diffuser 75, the amount of light reaching the exit end surface 75b of the diffuser 75 is the same. Therefore, the amount of light transmitted to the spectroscope 55 by the light receiving fiber 54 is the same. As a result, even when the wafer W is not stable in a certain horizontal plane during the rotation of the spin chuck 31 and a precession movement as shown in FIG. 3 is performed,
A stable amount of light can be transmitted to the spectroscope 55. That is, when the wafer W is in the posture shown by the solid line in FIG. 3, the reflected light from the surface of the wafer W follows the optical path L1 and reaches the diffuser 75. When the wafer W is in the posture shown by the alternate long and short dash line, The light reaches the diffuser 75 through the optical path L2. But in each case,
Since the diffuser 75 having a large diameter can receive the reflected light at the incident end surface 75a, the amount of light incident on the light receiving optical fiber 54 is stable.

When the processing liquid is supplied from the nozzle 40 and the spin chuck 31 is rotated, the surface of the wafer W is
There will be a treatment liquid layer having a complicated shape (see FIG. 7). Even in this situation, since the reflected light from the thin film on the surface of the wafer W can be incident on the large-diameter incident end face 75a, a stable amount of light can be incident on the light-receiving optical fiber 54. Thus, according to this embodiment, the wafer W is rotated regardless of whether the wafer W is rotated by the spin chuck 31 or whether the processing liquid is supplied from the nozzle 40 to the surface of the wafer W. The film thickness of the thin film on the surface can be satisfactorily detected.

Therefore, while the spin chuck 31 is rotated and the etching liquid is supplied to the wafer W from the nozzle 40, the film thickness of the surface can be measured in real time. As a result, when the thin film on the surface of the wafer W is etched halfway to leave a thin film of a predetermined thickness on the wafer W, the etching liquid and the pure water are removed based on the film thickness information measured in real time. Supply / stop can be controlled. As a result, a thin film having a highly accurately controlled film thickness can be left on the wafer W.

FIG. 6 is a flow chart for explaining the operation of the control unit 60. When the unprocessed wafer W is loaded into the processing chamber 20 and held by the spin chuck 31 (step S1), the target film thickness of the thin film on the wafer W is set (step S2), and the controller 60 rotates. The drive mechanism 35 is controlled to start rotation of the spin chuck 31 (step S3). Then, when the rotation of the spin chuck 31 is stabilized, the control unit 60 controls the three-way valves 45 and 46 to guide the etching liquid from the chemical liquid tank 41 to the nozzle 40 from the processing liquid supply passage 47 (step S4). . As a result, the etching liquid is supplied to the wafer W held by the spin chuck 31 and rotating. At this time, the control unit 60 controls the three-way valve 37 so that the processing liquid from the drainage pipe 36 is guided to the recovery pipe 38.

When the supply of the etching solution from the nozzle 40 is started, the control unit 60 starts the film thickness measurement based on the output from the spectroscope 55 (step S5). This film thickness measurement is continuously performed until the target film thickness set in step S2 is reached (step S6). When the film thickness of the thin film measured based on the output from the spectroscope 55 reaches the target film thickness (YES in step S6), the control unit 6
0 controls the three-way valve 45 to guide the chemical liquid from the pump 43 to the circulation path 49 and stop the supply of the etching liquid (step S7). After that, the control unit 60 controls the three-way valve 46.
The pure water from the pure water supply source 42 is guided to the nozzle 40 from the processing liquid supply path 47 by controlling the (step S
8). As a result, pure water is supplied from the nozzle 40 to the surface of the wafer W for a predetermined time. In this way, the etching liquid on the wafer W is washed away.

When the washing process is completed in this way, the control unit 6
0 controls the three-way valve 46 to stop the supply of pure water, and further controls the rotation drive mechanism 35 to rotate the spin chuck 31 at high speed in order to shake off the moisture on the surface of the wafer W to dry it. (Step S
9). When the drying process by such high speed rotation is completed (step S10), the control unit 60 causes the rotation drive mechanism 35 to operate.
Is controlled to stop the rotation of the spin chuck 31 (step S11). In this way, the wafer W is completely dried off, and then the processed wafer W is carried out of the chamber 20 by the main transfer robot 25 (see FIG. 1) (step S12).

As described above, according to this embodiment, the film thickness of the thin film is detected in real time during the process of supplying the etching liquid to the surface of the wafer W and etching the thin film on the surface to the middle of the film thickness. It Then, when the film thickness detection value reaches the target film thickness, the etching is stopped. As a result, a thin film whose target film thickness is controlled with high accuracy can be left on the surface of the wafer W. Although one embodiment of the present invention has been described above, the present invention can be implemented in other forms. For example, in the above embodiment, a wafer is taken as an example of the substrate to be processed, but the present invention can be applied to the processing of other types of substrates such as a glass substrate for a liquid crystal display panel and a substrate for an optical disc. You can

Further, in the above embodiment, the processing unit 21
24, the film thickness of the thin film on the surface of the wafer W is detected while the wafer W is being rotated and the processing liquid is being supplied. For example, the wafer being transferred by the main transfer robot 25 The thickness of the thin film on the surface may be measured. In addition, the spin chuck 31
The film thickness may be measured by the film thickness measuring device 50 while the nozzle 40 is not supplying any processing liquid, and the processing liquid is supplied from the nozzle 40 and the spin chuck With 31 stopped,
The thickness of the thin film on the surface of the wafer W may be measured.

Besides, various design changes can be made within the scope of the matters described in the claims.

[Brief description of drawings]

FIG. 1 is a schematic plan view for explaining a layout of a substrate processing apparatus according to an embodiment of the present invention.

FIG. 2 is an illustrative view showing a configuration of a processing unit.

FIG. 3 is an illustrative view for explaining a configuration of a film thickness measuring device.

FIG. 4 is a perspective view for explaining the structure of a diffuser.

FIG. 5 is a diagram showing how light propagates inside a diffuser.

FIG. 6 is a flowchart for explaining the flow of etching processing.

FIG. 7 is an illustrative view showing a state where the processing liquid is wavy on the substrate surface.

FIG. 8 is an illustrative view for explaining a precession motion that occurs when the substrate rotates.

[Explanation of symbols]

W wafer 11 Indexer robot 20 processing chamber 21-24 processing unit 25 Main transfer robot 27 Transport path 31 Spin chuck 35 rotation drive mechanism 40 nozzles 41 Chemical tank 42 Pure water supply source 47 Processing liquid supply path 50 Film thickness measuring device 51 Thickness Optical System 52 Optical fiber for projecting light 52a exit end 53 Floodlight 54 Optical fiber for receiving light 54a entrance end 55 Spectrometer 71 Light emitting / receiving window member 72 Achromatic lens 73 Half mirror 74 Total reflection mirror 75 diffuser 75a Incident end surface (rough surface) 75b Emitting end surface (rough surface) 75c Circumferential surface (polished surface) Angle corresponding to the total reflection angle of the A diffuser φ Angle corresponding to numerical aperture NA of optical fiber for receiving light

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yukihiro Takamura             4 Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto City, Kyoto Prefecture             No. 1 at Tenjin Kitamachi             Manufacturing Co., Ltd. (72) Inventor Toru Kuroiwa             4 Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto City, Kyoto Prefecture             No. 1 at Tenjin Kitamachi             Manufacturing Co., Ltd. F term (reference) 2F065 AA30 BB03 BB16 BB21 CC19                       CC31 CC32 DD06 HH11 LL02                       LL04 LL12 LL46 LL49 LL67                       MM04 PP13 PP22 TT02 UU07                 4M106 AA01 BA04 CA21 CA48 DH03                       DH40 DH55

Claims (6)

[Claims] 1. A light projecting unit for irradiating a film to be measured with light, a light receiving unit for receiving reflected light from the film to be measured, and a light receiving path extending from the film to be measured to the light receiving unit. Equipped,
A film thickness measuring device, comprising: a diffuser that diffuses and uniformizes reflected light from a film to be measured and emits the diffused light toward the light receiving unit. 2. The film thickness measuring device according to claim 1, wherein the diffuser is arranged in the light receiving path immediately before the light receiving portion. 3. A substrate processing apparatus for processing a substrate having a film formed on its surface, comprising: a substrate holding mechanism for holding the substrate; a drive mechanism for moving or rotating the substrate holding mechanism; A substrate comprising: a film thickness measuring device according to claim 1 or 2, for measuring a film thickness of a film on a surface of the substrate held by the substrate holding mechanism being moved or rotated by a mechanism. Processing equipment. 4. The substrate processing apparatus according to claim 3, further comprising a processing liquid supply mechanism that supplies a processing liquid to the substrate held by the substrate holding mechanism. 5. The processing liquid supply mechanism supplies the processing liquid to the substrate held by the substrate holding mechanism while the substrate holding mechanism is being moved or rotated by the driving mechanism. The substrate processing apparatus according to claim 4, wherein: 6. A substrate processing apparatus for processing a substrate having a film formed on a surface thereof, wherein a processing liquid supply mechanism supplies a processing liquid to the substrate, and the processing liquid is supplied by the processing liquid supply mechanism. 1 or 2 for measuring the film thickness of the film on the surface of the substrate on which the film is formed.
A substrate processing apparatus, comprising: the film thickness measuring apparatus as described above.