JP2012166127A - Thin film forming device and thin film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress film thickness dispersion in the repetition of film forming when a thin film is formed by a wet process in a thin film forming device and a thin film forming method.SOLUTION: The thin film forming device includes, as the thin film forming device 1 which forms the thin film by a liquid film forming material 11 by supplying the film forming material 11 on a film-formed body 50 and rotating the film-formed body 50, a device which has a rotation holding part 2 which holds the film-formed body 50 and rotates it; an optical characteristic measuring part which irradiates the film forming material 11 which is made a thin layer on the film-formed body 50 by the rotation of the rotation holding part 2 with measuring light L0 and measures an optical characteristic value made of at least one of the transmittance and reflectance of the film-formed body 50 including the film forming material 11; and a control unit 6 which stops the rotation drive of the rotation holding part 2 when the optical characteristic value measured by the optical characteristic measuring part reaches a target value corresponding to the target film thickness of the thin film in which the optical characteristic value measured by the optical characteristic measuring part is stored in advance.

Description

  The present invention relates to a thin film deposition apparatus and a thin film deposition method.

Conventionally, when forming a thin film, a dry process such as a vacuum evaporation method or a sputtering method is used. However, when a thin film is formed on a film-deposited body having a finite curvature such as a lens, the incident angle of the thin film-forming particles that form the thin film varies depending on the curvature of the film-forming surface in the dry process, so the film thickness is uniform. There is a problem that it is difficult to form a thin film. In addition, even when a large area film is formed, there is a problem that the film thickness tends to be non-uniform because the distribution of thin film forming particles tends to vary. Furthermore, since the dry process cannot form a film in an air atmosphere, a vacuum chamber or the like is required, and there is a problem that the apparatus becomes large.
For this reason, in place of the dry process, a wet process (wet process) that can easily achieve film thickness uniformity even on a film-forming surface having a finite curvature or a film-forming surface with a large area and that can be formed even in an air atmosphere. ) Has been proposed. The wet process is a method of forming a film by applying a liquid to a substrate and drying and heat-treating it by spin coating, dipping, spraying, roll coating, or the like.
For example, in the spin coating method, a liquid thin film forming material is dropped on a film formation body, and the film formation body is rotated at a high speed. The dropped thin film forming material spreads along the film formation body in a short time by centrifugal force, and a thin film having a uniform film thickness is formed. At this time, the film thickness is determined by the number of rotations of the film formation body, the type of thin film forming material, concentration, viscosity, dripping amount, temperature and humidity environment, and the like.
However, the absolute value of the film thickness is likely to change due to variations in the number of rotations of the deposition target during film formation, changes in the concentration of the thin film forming material over time, changes in the temperature and humidity environment, and the like.
As a method for controlling the film thickness in such a wet process, Patent Document 1 discloses a coating unit for applying a photoresist to a semiconductor wafer in a coating thickness control method for controlling the thickness of a photoresist applied to a semiconductor wafer. To obtain information on the coating conditions for a predetermined number of samples with different coating conditions applied to the semiconductor wafer with photoresist, and acquire information on the film thickness for each of the samples. Plotting the coating conditions and the corresponding film thickness, creating an approximate curve for the predetermined coating conditions and the corresponding film thickness based on the plot, and setting a target value in advance based on the approximate curve Calculating a correction value related to a predetermined coating condition corresponding to the thickness of the photoresist being Generating a control signal for controlling the predetermined application condition of the application unit based on the calculated correction value relating to the predetermined application condition, and a coating film thickness control method is described. .
The correction related to the coating condition in Patent Document 1 corrects the number of rotations of a motor that rotates a semiconductor wafer.

Japanese Patent Laid-Open No. 2002-374343

However, the conventional thin film deposition apparatus and thin film deposition method as described above have the following problems.
In the technique described in Patent Document 1, a sample is prepared and a film thickness is measured, and then the number of rotations of a motor that rotates a semiconductor wafer that is a deposition target is corrected. Although the change is prevented, the change in the film thickness due to the influence of the change in the liquid concentration and viscosity of the thin film forming material over time and the change in the film forming environment cannot be prevented. For this reason, when the film formation is repeated with the film formation target changed, there is a problem that the film thickness varies if the liquid concentration of the thin film forming material changes over time or the temperature and humidity of the film formation environment fluctuate. is there.

  The present invention has been made in view of the above problems, and when forming a thin film by a wet process, a thin film forming apparatus and a thin film forming apparatus capable of suppressing variations in film thickness during repeated film formation. An object is to provide a membrane method.

  In order to solve the above problems, the thin film deposition apparatus of the present invention supplies a liquid thin film forming material onto a film formation target, and rotates the film formation target to form a thin film using the thin film formation material. A thin film forming apparatus that holds and rotates the film forming body, and measures the thin film forming material that is thinned on the film forming body by the rotation of the rotation holding unit. An optical property measuring unit that measures the optical property value of at least one of transmittance and reflectance of the film-forming body including the thin film forming material by irradiating light, and measured by the optical property measuring unit A rotation control unit that stops the rotation driving of the rotation holding unit when the optical characteristic value that has been reached reaches a target value corresponding to a target film thickness of the thin film stored in advance.

  In the thin film deposition apparatus of the present invention, the optical property measurement unit irradiates multicolor light as the measurement light, measures the optical property values at a plurality of wavelengths included in the multicolor light, and performs the rotation control. The unit stores the target values corresponding to the plurality of wavelengths in advance, and all of the plurality of optical characteristic values measured by the optical characteristic measurement unit reach the target values corresponding to the respective wavelengths. In this case, it is preferable to stop the rotation driving of the rotation holding portion.

  In the thin film deposition apparatus for measuring optical characteristic values at a plurality of wavelengths according to the present invention, the plurality of wavelengths are preferably included in a range of 400 nm to 700 nm.

  In the thin film deposition apparatus for measuring optical property values at a plurality of wavelengths according to the present invention, the optical property measuring unit measures the optical property value as a spectrum including a wavelength range of 400 nm to 700 nm, It is preferable that the rotation control unit stores an allowable distribution range of the spectral spectrum corresponding to the target film thickness of the thin film as the target value.

  The thin film deposition method of the present invention is a thin film deposition method in which a liquid thin film forming material is supplied onto a film formation target, and the film formation target is rotated to form a thin film using the thin film formation material, After the thin film forming material is supplied onto the film formation body, a thin film is formed on the film formation body by starting rotation of the film formation body and rotating the film formation body. An optical characteristic measuring step of irradiating the thin film forming material with measurement light to measure an optical characteristic value comprising at least one of transmittance and reflectance of the film-forming body including the thin film forming material; A determination step for determining whether or not the optical characteristic value measured in the optical characteristic measurement step has reached a target value corresponding to the target film thickness of the thin film stored in advance, and the optical characteristic value in the determination step is Based on the determination that the target value has been reached, the rotational drive of the film forming body is performed. A step of stopping the, the method comprising.

  According to the thin film deposition apparatus and the thin film deposition method of the present invention, the optical characteristic value of the thin film forming material that is thinned on the deposition target by rotation is measured, and the optical characteristic value corresponds to the target film thickness. Since the rotational driving of the film forming body is stopped after reaching the target value, there is an effect that it is possible to suppress the film thickness variation when the thin film is formed by the wet process.

It is a typical device block diagram which shows the structure of the thin film film-forming apparatus which concerns on the 1st Embodiment of this invention. It is a typical top view which shows the relationship between the to-be-film-formed body formed into a film by the thin film forming apparatus which concerns on the 1st Embodiment of this invention, and a measurement position. It is a functional block diagram which shows the function structure of the control unit of the thin film film-forming apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart explaining the thin film film-forming method which concerns on the 1st Embodiment of this invention. It is a schematic diagram explaining the measurement principle of the film thickness in the thin film film-forming apparatus which concerns on the 1st Embodiment of this invention. It is a graph for demonstrating the target value of the optical characteristic value in the thin film forming apparatus which concerns on the 1st Embodiment of this invention. It is a typical apparatus block diagram which shows the structure of the thin film film-forming apparatus which concerns on the 2nd Embodiment of this invention. It is a graph for demonstrating the target value of the optical characteristic value in the thin film forming apparatus which concerns on the 2nd Embodiment of this invention. It is a typical apparatus block diagram which shows the structure of the thin film film-forming apparatus which concerns on the 3rd Embodiment of this invention. It is a typical top view which shows the relationship between the to-be-film-formed body formed into a film by the thin film forming apparatus which concerns on the 3rd Embodiment of this invention, and a measurement position. It is typical sectional drawing which shows an example of the optical element manufactured using the thin film film-forming method concerning the 4th Embodiment of this invention. It is a flowchart explaining the thin film film-forming method which concerns on the 4th Embodiment of this invention. It is a graph for demonstrating the target value of the optical characteristic value at the time of film-forming of the 1st layer in the thin film film-forming method concerning the 4th Embodiment of this invention. It is a graph for demonstrating the target value of the optical characteristic value at the time of film-forming of the 2nd layer in the thin film film-forming method concerning the 4th Embodiment of this invention. It is a graph for demonstrating the target value of the optical characteristic value at the time of the film-forming of the 3rd layer in the thin film film-forming method concerning the 4th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A thin film deposition apparatus according to a first embodiment of the present invention will be described.
FIG. 1 is a schematic apparatus configuration diagram showing the configuration of a thin film deposition apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic plan view showing the relationship between the film formation target and the measurement position formed by the thin film deposition apparatus according to the first embodiment of the present invention. FIG. 3 is a functional block diagram showing a functional configuration of a control unit of the thin film deposition apparatus according to the first embodiment of the present invention.

As shown in FIG. 1, the thin film deposition apparatus 1 of the present embodiment supplies a liquid film deposition material 11 (thin film formation material) onto a film formation target 50, and rotates the film formation target 50 to form a liquid. This is an apparatus for forming a thin film using the film forming material 11.
The film-forming body 50 is not particularly limited as long as the film-forming surface 50a having a surface shape capable of thinning the film-forming material 11 disposed on the surface by centrifugal force is formed. For example, a glass substrate having a smooth flat surface as the film formation surface 50a, or an optical element base material on which a convex surface having a large curvature radius, a concave lens surface, or a reflection surface is formed as the film formation surface 50a can be employed. . As a magnitude | size of a curvature radius, 3 mm to infinity (plane) is suitable, for example.
Further, as the material of the film formation target 50, in the present embodiment, glass or synthetic resin having optical transparency is suitable.
Further, the outer shape of the film formation target 50 is not particularly limited.
In the following, an example of a glass substrate which is a smooth disc having an outer diameter D ₀ (see FIG. 2) of 25 mm and a thickness of 1 mm will be described as an example of the film formation target 50. As an example, the material of the film formation target 50 will be described in the case of S-LAH58 (trade name; manufactured by OHARA INC., N _d = 1.88).
Here, “n _d ” is the refractive index at the d-line. Hereinafter, the refractive index at a specific wavelength λ is expressed as “n _λ ” as a numerical value obtained by measuring the wavelength λ in nm.

The film forming material 11 is a material for forming a thin film on the film formation surface 50a, and an appropriate material can be adopted as long as the optical characteristics change according to the film thickness. Examples of optical characteristics include reflectance, transmittance, and their spectral characteristics.
Examples of the type of thin film include optical thin films formed to change optical characteristics such as reflectance, transmittance, and polarization characteristics of the film formation surface 50a, such as an antireflection film, a reflective film, a semi-transmissive film, A wavelength selection film, a polarizing film, a light absorption film, etc. can be mentioned.
As another example of the type of thin film, there is a thin film that changes the mechanical, physical, and electrical characteristics of the film formation surface 50a and that needs to be managed with high accuracy. be able to. Examples of such a thin film include a hard coat film, an antistatic film, a conductive film, a water repellent film, a film repellent oil, etc. used on an optical surface that transmits and reflects light functionally in an optical element. Can be mentioned.
Hereinafter, as an example, a polymerizable compound coating agent (n ₅₂₀ = 1.36) containing hollow silica, which is a low refractive index material, is used as a material of the film forming material 11 to form a target on the film formation surface 50a. An example in the case of forming a single-layer thin film having a film thickness t ₀ of 95.6 nm will be described.
As will be described later, this thin film functions as an antireflection film by causing interference at a wavelength of 520 nm to cancel reflected light components.
When the film thickness of the film forming material 11 changes after curing, the target film thickness t ₀ is set to a film thickness that provides a necessary film thickness after curing.

  The schematic configuration of the thin film deposition apparatus 1 includes a rotation holding unit 2, a drive unit 4, a drive transmission unit 3, a material supply unit 5, a light source 9, an optical fiber 10, a light receiving lens 8, an optical fiber 7, and a control unit 6. .

The rotation holding unit 2 holds and rotates the film formation target 50. The rotation holding unit 2 of the present embodiment supports the film formation target 50 so that the center axis C of the film formation target 50 is aligned with the vertical axis and the film formation surface 50a faces upward. The film formation target body 50 can be rotated as a central axis of rotation.
For this reason, the rotation holding part 2 is formed in a cylindrical shape having a through hole 2b in the center, and is supported by a bearing (not shown) so as to be rotatable around a vertical axis. A chuck 2 a that receives the outer peripheral portion of the back surface 50 b of the film formation body 50 from below and holds the side surface of the film formation body 50 so as to be detachable in the radial direction is provided at the upper end of the rotation holding unit 2.

The drive unit 4 rotates the rotation holding unit 2, and a DC motor is employed in the present embodiment. The drive unit 4 is electrically connected to the control unit 6, and based on a control signal from the control unit 6, it is possible to control the start and stop of the rotation drive and the rotation speed.
Note that the stop control of the rotation drive in the present embodiment means control for stopping the supply of the rotation drive force. For this reason, the rotation holding unit 2 starts decelerating with the stop of the rotation drive, but does not stop immediately. In order to shorten the time required for complete stop, the drive unit 4 may include an appropriate brake.
The steady rotation speed of the drive unit 4 may be set as appropriate according to the viscosity of the film forming material 11, and can be set, for example, in the range of 3000 rpm to 5000 rpm.

  The drive transmission unit 3 is a rotation transmission mechanism that transmits the rotational driving force of the drive unit 4 to the rotation holding unit 2. In the present embodiment, as an example, a drive gear 3a provided on the rotation shaft of the rotation holding unit 2 and The driven gear 3b is fixed to the outer peripheral portion of the rotation holding portion 2.

  The material supply unit 5 supplies the film forming material 11 onto the film formation surface 50 a of the film formation target 50 held by the rotation holding unit 2. In the present embodiment, the material storage unit 5b that stores the film forming material 11, and the material dropping unit 5a that drops a predetermined amount of the film forming material 11 in the material storage unit 5b toward the center O of the film formation surface 50a; Is provided.

The light source 9 forms measurement light L ₀ for measuring optical characteristics corresponding to the film thickness of the film forming material 11 to be thinned on the film formation surface 50a.
The measurement light L ₀ may be monochromatic light or multicolor light including white light as long as it includes light having a wavelength capable of measuring optical characteristics to be described later. In the present embodiment, the wavelength light having a wavelength of 400 nm to 700 nm is used. A white light source is used. Specifically, a halogen lamp is used.
The light source 9, and guides the measurement light L _0, the optical fiber 10 for emitting connected measuring light L ₀ from the connected end and formed opposite the fiber end face 10a to the light source 9.
In the present embodiment, the optical fiber 10 has a through hole 2b from the lower side of the rotation holding unit 2 so that the fiber end surface 10a is positioned in the vicinity of the back surface 50b of the film formation target 50 held by the rotation holding unit 2. It is distributed inside.
The position of the plan view of the fiber end face 10a, as shown in FIG. 2, the center of the fiber end faces 10a, the distance D _1/2 with respect to the center O of the deposition material 50 on the deposition surface 50a ( However, it is set at a position overlapping with the point P separated by 0 <D ₁ <D ₀ ) in the vertical direction.

The light receiving lens 8 is an optical element that condenses light that passes through the film formation target 50 out of the measurement light L ₀ emitted from the fiber end face 10 a and optically couples it to the optical fiber 10. In the present embodiment, the light receiving lens 8 is disposed so that the optical axis thereof is aligned with the vertical axis passing through the point P on the film formation surface 50a.
For this reason, the fiber end surface 10 a of the optical fiber 10 and the light receiving lens 8 are disposed to face each other with the film formation target body 50 held by the rotation holding unit 2 interposed therebetween. As a result, when the spin holder 2 rotates together with the HiNarumakutai 50, the fiber end surface 10a and the light receiving lens 8 is moved relative to a circle of diameter D ₁ relative to HiNarumakutai 50, the diameter D ₁ At various locations on the circumference, the measurement object L ₀ is irradiated from the fiber end face 10 a to the film formation target 50, and the transmitted light can be condensed by the light receiving lens 8.
The position of the point P is a measurement center position of optical characteristics to be described later, that is, a measurement center position of the film thickness when forming a thin film. Therefore, it may be set anywhere within the effective region for forming the thin film, but in the present embodiment, as an example, D ₁ /2=7.5 (mm). That is, the radius of the film formation target 50 is set to an intermediate portion that is divided into 3: 2.

  The optical fiber 7 is a light guide unit that guides the light collected by the light receiving lens 8 to the control unit 6. One end face of the fiber is disposed at the light collecting position of the light receiving lens 8, and the other fiber end face is the control unit 6. Are connected to a photometric unit 13 (see FIG. 3) described later.

The control unit 6 controls the apparatus operation of the thin film deposition apparatus 1, and as shown in FIG. 3, the drive unit 4, the material supply unit 5, and the light source 9, which are each device part to be controlled, are electrically connected. It is connected to the. Further, for example, an operation unit 12 including an operation panel, a keyboard, a mouse, and the like is connected so that operation input for performing a control operation and information necessary for control can be input.
As a functional configuration of the control unit 6, a photometric unit 13, a storage unit 15, and a control unit 14 are provided.

The photometric unit 13 receives incident light that is incident on the light receiving lens 8 and guided by the optical fiber 7, measures the amount of light at a specific wavelength, and calculates an optical characteristic value corresponding to the film thickness. The value is sent to the control unit 14.
As a specific configuration of the photometry unit 13, for example, a configuration including a wavelength selection filter that transmits light having a wavelength corresponding to a specific wavelength, a light receiving element, and an arithmetic processing unit that calculates an optical characteristic value based on the amount of received light, Alternatively, it is possible to adopt a configuration including a spectrophotometer that measures the amount of spectral light instead of the wavelength selection filter and the light receiving element in this configuration. Hereinafter, an example in which a spectroscopic measuring device is provided will be described. For this reason, the photometry unit 13 can transmit a plurality of optical characteristic values, a spectral spectrum of the optical characteristic values, and the like to the control unit 14 as necessary.
As the optical characteristic value in the present embodiment, the transmittance of the film-forming body 50 including the film-forming material 11 that forms a thin film on the film-forming surface 50a during film formation is employed.
For this reason, the arithmetic processing unit of the photometry unit 13 uses the received light amount at a specific wavelength when the film formation target 50 is held on the rotation holding unit 2 as a reference light amount, and forms a film on the rotation holding unit 2 for this reference light amount. The transmittance at a specific wavelength can be calculated from the ratio of the amount of light received at the same wavelength when the body 50 is held.

The storage unit 15 stores data input from the operation unit 12 and calculation results calculated by the photometric unit 13 and the control unit 14 so that the photometric unit 13 and the control unit 14 can refer to the data.
As data input from the operation unit 12, a target value corresponding to the film thickness of the thin film to be formed on the film formation target 50 by the thin film deposition apparatus 1 can be cited. When a thin film is formed on the film formation surface 50a, transmitted light causes interference by the thin film, so that the spectral transmittance changes according to the film thickness. If the refractive index of the film formation target 50 and the refractive index of the film forming material 11 are known, there is a correspondence between the film thickness of the thin film and the transmittance at a specific wavelength.
Therefore, in the present embodiment, the transmittance and the transmittance allowable range corresponding to the target film thickness t ₀ that is the thickness of the thin film to be formed and the allowable range of the film thickness are calculated in advance by numerical simulation or the like, and the transmittance is calculated. The allowable range is stored as a target value. That is, the target value is given as a target numerical range, specifically, a lower limit value and an upper limit value.
In this specification, “the optical characteristic value has reached the target value” means that the optical characteristic value has reached the target numerical range unless otherwise specified. In the present embodiment, the optical characteristic value is the transmittance, and the target numerical value range is the transmittance allowable range.
For example, the film formation target 50 is S-LAH58 (trade name), the film formation material 11 is a polymerizable compound coating agent containing hollow silica, and the target film thickness t ₀ of the film formation material 11 is 95.6 nm. When the allowable range is ± 2% of the target film thickness t ₀ , 99.975% to 100% can be adopted as the target value of the transmittance at the wavelength of 520 nm stored in the storage unit 15.

The control unit 14 performs control to turn on and off the light source 9 based on an operation input from the operation unit 12 and to perform transmittance measurement by the photometry unit 13 with the light source 9 turned on.
Further, the control unit 14 performs control to drop a predetermined amount of the film forming material 11 from the material supply unit 5 based on an operation input from the operation unit 12.
In addition, after the material supply unit 5 is dropped, the control unit 14 performs control to start driving by the driving unit 4 while repeatedly measuring the transmittance by the photometric unit 13. Then, the transmittance transmitted from the photometry unit 13 is compared with the target value of the transmittance stored in the storage unit 15, and when the transmittance transmitted from the photometry unit 13 reaches the target value, the drive unit 4 Control to stop driving.

  In the present embodiment, the control unit 6 is configured by appropriate hardware including a spectrometer and a computer including a CPU, a memory, an input / output interface, an external storage device, and the like. The above calculation function and control function are realized by executing a calculation program and a control program corresponding to each of the calculation function and the control function on this computer.

In such a configuration of the thin film deposition apparatus 1, the light source 9, the optical fiber 10, the light receiving lens 8, the optical fiber 7, and the photometry unit 13 of the control unit 6 are placed on the film formation target 50 by the rotation of the rotation holding unit 2. An optical property measurement unit is configured to irradiate the film forming material 11 to be thinned with the measurement light L ₀ and measure the optical property value including the transmittance of the film formation target 50 including the film forming material 11. Yes.
The control unit 14 of the control unit 6 rotates the rotation holding unit 2 when the optical characteristic value measured by the optical characteristic measurement unit reaches a target value corresponding to the target film thickness of the thin film stored in advance. The rotation control unit to be stopped is configured.

Next, the operation of the thin film deposition apparatus 1 will be described focusing on the thin film deposition method of the present embodiment.
FIG. 4 is a flowchart for explaining a thin film deposition method according to the first embodiment of the present invention. FIGS. 5A, 5 </ b> B, and 5 </ b> C are schematic diagrams for explaining the measurement principle of the film thickness in the thin film deposition apparatus according to the first embodiment of the present invention. FIG. 6 is a graph for explaining the target value of the optical characteristic value in the thin film deposition apparatus according to the first embodiment of the present invention. In FIG. 6, the horizontal axis represents wavelength (nm) and the vertical axis represents transmittance (%).

In order to form a thin film of the film forming material 11 on the film formation surface 50a by the thin film forming apparatus 1, the film is formed by executing steps S1 to S6 according to the flowchart shown in FIG. Do.
First, in step S <b> 1, the film formation target 50 is held on the chuck 2 a and set on the rotation holding unit 2 in a state where the driving of the driving unit 4 is stopped. In the present embodiment, since the installation atmosphere of the thin film deposition apparatus 1 may be an air atmosphere, the film formation target 50 may be set manually, for example, or may be set using a robot or the like.
While the film formation target 50 is held by the rotation holding unit 2, the light source 9 is turned on, the measurement light L ₀ is emitted from the fiber end surface 10 a, and the amount of light collected through the light receiving lens 8 is measured. Measurement is performed by the unit 13. At this time, as shown in FIG. 5 (a), the measuring light L ₀ is other is reflected part by the rear surface 50b and transmitted as a measurement light L _T1, it reaches the deposition surface 50a. A part in deposition surface 50a is reflected as reflected light _{L R2.} Therefore, the amount of light measured by the optical measuring unit 13 is a light intensity of the measurement light L _T2 excluding the component as a reflected light L _R2 from the measurement light L _T1.
In the present embodiment, for using the change of transmittance at deposition surface 50a, the light intensity of the measurement light L _T1 used as a reference quantity for determining the transmission rate.
Amount _{Q T1} of the measurement light _{L T1} is obtained by adding the quantity _{Q R2} of the reflected light _{L R2} to the light amount _{Q T2} of the measurement light _{L T2.} In the present embodiment, the light quantity Q _T1 of the measurement light L _T1 is the reflectance R _λ (%) for each wavelength calculated from the refractive index data of the glass material (S-LAH 58) constituting the film formation target 50 and air. Is obtained from the following equation (1).

Q _T1 = Q _T2 × 100 / (100−R _λ ) (1)

Here, the reflectance R _λ is obtained by the following calculation.
For example, the refractive index n _λ of the glass material S-LAH 58 is expressed by a dispersion formula such as the following equation (2) using the wavelength λ (nm) according to the glass material manufacturer.

Here, A ₁ , A ₂ , A ₃ , B ₁ , B ₂ , B ₃ are constants as follows.
A ₁ = 1.778764964
A ₂ = 6.552635600 × 10 ⁻¹
A ₃ = 1.7991464
B ₁ = 8.447378536 × 10 ⁻³
B ₂ = 3.113126408 × 10 ⁻²
B ₃ = 1.32788001 × 10 ⁺²

The reflectance R (%) at the glass material interface is expressed by the following equation (3), where n _{1 is} the refractive index of the glass material and n ₂ is the refractive index of the air.

R = {(n ₁ −n ₂ ) / (n ₁ + n ₂ )} ² × 100 (3)

By substituting n _λ calculated from the above equation (2) and 1 that is the refractive index of air into n ₁ and n ₂ in the above equation (3), the reflectance R _{λ at} the interface of the glass material at the wavelength _λ is obtained. The light quantity Q _T1 of the measurement light L _T1 that is the reference light quantity is obtained by the above equation (1).
This reference light quantity is stored in the storage unit 15. In the present embodiment, since the metering unit 13 is provided with a spectrophotometer, the measurement light L _T2 is the spectral intensity is measured. Accordingly, the spectral light quantity for each wavelength is stored as the reference light quantity.
Thus, step S1 is completed.
Even when film formation is performed under the same conditions, the measurement of the reference light amount is performed every film formation because the transmittance changes due to a change in the light amount of the light source 9 with time and an error in the thickness of the film formation target 50. desirable.
By measuring the reference light quantity in this way, it is possible to correct measurement errors due to changes in the light quantity of the light source 9 over time and variations in the thickness of the film formation target 50 and the surface state of the back surface 50b.

Next, in step S <b> 2, the operator inputs a measurement start operation from the operation unit 12. The control unit 14 that has detected the operation input drops a predetermined amount of the film forming material 11 necessary for forming a thin film from the material dropping unit 5 a of the material supply unit 5. As shown in FIG. 5A, the dropped film forming material 11 is supplied as droplets on the center O of the film formation surface 50a.
In the example of this embodiment, the amount of the film forming material 11 is 0.02 mL.
This is the end of step S2.

Next, in step S <b> 3, the control unit 14 sends a control signal for starting driving to the driving unit 4 to drive the driving unit 4 to start rotation of the rotation holding unit 2. In the present embodiment, as an example, the drive unit 4 is driven so that the rotation number of the rotation holding unit 2 is 3000 rpm.
This is the end of step S3.
Step S3 constitutes a step of starting the rotational driving of the film-forming body 50 after supplying the film-forming material 11 onto the film-forming body 50 in the thin film deposition method of the present embodiment.

Next, in step S4, optical characteristics are measured.
The control unit 14 sends a control signal for starting the transmittance measurement to the photometric unit 13 after sending a control signal for starting the drive to the drive unit 4. Thereby, the photometry unit 13 repeats the transmittance measurement at a specific wavelength for a predetermined sampling time until a control signal for stopping the measurement is sent from the control unit 14.
In the example of the present embodiment, the transmittance is calculated by dividing the received light amount at λ ₁ = 520 (nm) measured by the spectrophotometer of the photometric unit 13 by the reference light amount stored in the storage unit 15, It is sent to the control unit 14. In this way, the transmittance on the emission side of the film formation target 50 is obtained.
When the transmittance is sent to the control unit 14, step S4 ends, and the process proceeds to step S5.
In step S <b> 4, the film-forming material 11 that is thinned on the film-forming body 50 by the rotation of the film-forming body 50 is irradiated with the measuring light L ₀ , and the film-forming body 50 including the film-forming material 11 is irradiated. An optical characteristic measurement step for measuring an optical characteristic value consisting of transmittance is configured.

In step S4, since the film formation target 50 is rotated, a centrifugal force acts on the film formation material 11 on the film formation surface 50a as shown in FIG. The film moves from the center O to the outer peripheral side, expands in a circular shape in plan view on the film formation surface 50a, and thinning proceeds.
Further, when the rotation is continued, the film forming material 11 covers the entire film forming surface 50a and is gradually discharged radially outward from the outer peripheral portion of the film forming surface 50a. Therefore, rotation is the thickness of each place on the deposition surface 50a gradually decreases as one proceeds, eventually as shown in FIG. 5 (c), a uniform thin film having a target film thickness t ₀ on deposition surface 50a 110 is formed.

For example, as shown in FIG. 5A, in the state before the start of rotation or immediately after the rotation, the film forming material 11 is gathered in the vicinity of the center O, and the measurement light L _T1 attenuated at the back surface 50b is generated. In the vicinity of the transmitting point P, the thin film of the film forming material 11 is not formed. At this time, when the measurement light L _T1 incident and transmitted from the back surface 50b reaches the film formation surface 50a, a part of the measurement light L _T1 is received as the transmitted light L _{T2 in} accordance with the transmittance specific to the film formation surface 50a. lens 8 passes toward (see FIG. 1), others are reflected on the rear surface 50b side as reflected light _{L R2.} Therefore, the amount of received light of the photometry unit 13 becomes smaller than the amount of the measurement light L _T1 at wavelength lambda _1.

Further, as shown in FIG. 5B, when the thin film forming material 11 spreads slightly to the outer peripheral side from the point P and does not completely reach the outer peripheral part, the film forming material 11 at the point P is used. the film thickness _{t 3} of is thicker than the target thickness _{t 0.}
Further, when the film forming material 11 is further thinned, the film thickness at each point becomes the target film thickness t _{0 as} shown in FIG.
That is, at the point P, the target film thickness t ₀ is reached when the film forming material 11 reaches the point P from the state where the film thickness of the film forming material 11 is 0 as time elapses from the start of the rotation of the film formation target 50. The film thickness gradually decreases after the thicker initial film thickness is reached. Note that the time for the tip of the film forming material 11 to pass the point P is sufficiently shorter than the sampling time for transmittance measurement, and therefore the change in the increase in film thickness is stepped. Therefore, changes during the film thickness increase until reaching the initial film thickness are not measured.

Here, the relationship between such a change in film thickness and a change in transmittance will be described.
The spectral transmittance when the thin film having the target film thickness t ₀ is formed on the film formation surface 50 a by the film forming material 11 is as shown by a curve 100 in the graph shown in FIG. 6 in the example of this embodiment. .
That is, the curve 100 has a transmittance of 96.1% at a wavelength of 370 nm, the transmittance increases monotonously from the wavelength of 370 nm to the wavelength of 520 nm (= λ ₁ ), and reaches a maximum transmittance of 100% at the wavelength of 520 nm. From 520 nm toward the wavelength of 750 nm, the transmittance decreases monotonously, and the transmittance becomes 97.9% at the wavelength of 750 nm.
Thus, the thin film having the target film thickness t ₀ of the film forming material 11 is a good antireflection film for the wavelength of 520 nm.
Thickness of the thin film, the spectral transmittance in the case that deviates from the target thickness t ₀ is not particularly shown, a wavelength to be 100% transmission is shifted from the wavelength lambda _1, the horizontal axis curve 100 in the graph The shape is almost shifted in the direction. For example, in the case of the film thickness t ₃ (> t ₀ ) shown in FIG. 5B, since interference with light having a wavelength longer than the wavelength λ ₁ becomes significant, the curve 100 is on the long wavelength side (right in the figure). The shape is shifted in the direction).
As a result, in the state of the film thickness t ₃ , the transmittance at the wavelength λ ₁ is smaller than the transmittance at the target film thickness t ₀ . Thus, there is a correspondence between the transmittance at the wavelength λ ₁ and the film thickness of the film forming material 11. Specifically, as the film thickness at the point P is increased from a state where the film thickness is greater than the target film thickness t ₀ to the target film thickness t ₀ , the wavelength is shorter than the wavelength λ ₁ in the curve 100 (left side in the figure). The transmittance increases at the same rate as moving toward the wavelength λ ₁ on the curve.
For this simulation spectral transmittance results, if the transmittance is accustomed to 99.975% to 100%, it can be seen that the fall in the film thickness range corresponding to of ± 2% target film thickness _{t 0.}
Further, for example, when the allowable range of the film thickness is ± 1.5% of the target film thickness t ₀ , the transmittance may be 99.985% to 100%.

Next, in step S5, the control unit 14 compares the transmittance transmitted from the photometry unit 13 with a transmittance allowable range that is a target numerical range stored in the storage unit 15, and is within the target numerical range. In step S6, the process proceeds to step S6.
If the transmittance is within the permissible transmittance range, the transmittance has reached the target value. For this reason, it can be determined that the film thickness corresponding to the transmittance is within ± 2% of the deviation from the target film thickness t ₀ . .
When the example of this embodiment was implemented, the time until the transmittance reached the target value was about 10 seconds from the start of the rotational drive.

  If the transmittance is out of the target numerical value range, the process proceeds to step S4. However, in the second and subsequent steps S4, the control unit 14 does not send a control signal, and the photometry unit 13 measures the transmittance at regular sampling times and sends it to the control unit 14.

As described above, step S5 constitutes a determination step for determining whether or not the optical characteristic value has reached a target value corresponding to the target film thickness of the thin film stored in advance.
Further, in the present embodiment, the specific wavelength that takes the maximum value of the transmittance is the wavelength of the measurement light L ₀ , the upper limit value of the target numerical range is the maximum value of the transmittance, and the lower limit value is higher than the maximum value of the transmittance. In this example, a small transmittance is set. When determining in the vicinity of such a maximum value, it is sufficient to determine that the value is equal to or greater than the lower limit value. Therefore, in the example of this embodiment, it is sufficient to determine whether the lower limit value is 99.975% or more.

Step S <b> 6 is a step performed after it is determined in step S <b> 5 that the optical characteristic value has reached the target value. A control signal for stopping the driving of the driving unit 4 is transmitted from the control unit 14, and Stop driving. Thereby, the rotation drive of the rotation holding part 2 is stopped, and the rotation holding part 2 is decelerated. As a result, since the centrifugal force acting on the film forming material 11 is attenuated, the movement of the film forming material 11 by the centrifugal force is stopped.
In this way, the film thickness of the film forming material 11 is maintained at a constant film thickness value when the rotation drive is stopped. A thin film reaching the target film thickness t ₀ ± 2% is formed on the film formation surface 50a.
This is the end of step S6.

  As described above, step S6 constitutes a step of stopping the rotational driving of the film formation target 50 based on the determination that the optical characteristic value has reached the target value in the determination step (step S5).

When step S <b> 6 is completed and the rotation of the rotation holding unit 2 is stopped, a necessary curing process or the like is performed according to the material of the film forming material 11. For example, in the polymerizable compound coating agent containing the hollow silica of the example of the present embodiment, the film formation target body 50 is removed from the rotation holding unit 2 and put into a drying furnace heated in advance to 200 ° C. for 10 minutes. Harden. As a result, a single-layer thin film of the film forming material 11 is formed on the film formation surface 50 a on the film formation target 50.
This is the end of the thin film formation method of the present embodiment.

According to the thin film deposition apparatus 1 of the present embodiment, the transmittance of the deposition material 11 to be thinned on the deposition target body 50 held and rotated by the rotation holding unit 2 is measured, and the transmittance is the target. After reaching the target value corresponding to the film thickness t ₀ , the rotational driving of the film formation target 50 is stopped. That is, since the film formation is performed while indirectly measuring the film thickness during the film formation, it is possible to perform the film formation so that the film thickness of the thin film is surely within an allowable range.
For this reason, when the film formation is repeated, for example, the number of rotations of the rotation holding unit 2 fluctuates, the liquid concentration and viscosity of the film formation material 11 change over time, and the temperature and humidity of the film formation environment fluctuate. For example, even if a factor causing a variation in film thickness occurs, the variation in film thickness can be kept within an allowable range.
Therefore, when forming a thin film by a wet process, it is possible to suppress variations in film thickness due to repeated film formation.

[Second Embodiment]
A thin film deposition apparatus according to a second embodiment of the present invention will be described.
FIG. 7 is a schematic diagram showing the configuration of a thin film deposition apparatus according to the second embodiment of the present invention.

The thin film deposition apparatus 1A of the present embodiment is an example in the case where the reflectance is adopted as the optical characteristic value, and as shown in FIG. 7, the drive transmission unit 3 of the thin film deposition apparatus 1 of the first embodiment is used. Are replaced with a rotation holding unit 2A and a driving unit 4A, respectively, instead of the rotation holding unit 2 and the driving unit 4.
In addition, the arrangement positions of the light source 9, the optical fiber 10, the optical fiber 7, and the light receiving lens 8 are changed in order to measure the reflected light from the thin film on the film formation surface 50a.
Further, in order to perform reflectance measurement, the storage unit 15 of the control unit 6, the target film thickness t ₀ and tolerances on the corresponding reflectance and reflectance allowable each range of thickness which is the thickness of a thin film to be formed Is calculated in advance by numerical simulation or the like, and the reflectance allowable range is stored as a target value.
Below, it demonstrates centering on a different point from the said 1st Embodiment. The film forming material 11, the film formation target 50, the conditions of the film thickness to be formed, and the like will be described using the same example as that used in the first embodiment.

The rotation holding portion 2A is obtained by removing the driven gear 3b and the through hole 2b from the rotation holding portion 2 of the first embodiment, and includes a chuck 2a at the upper end portion as in the first embodiment.
The drive unit 4A is a DC motor that is connected to the lower end of the rotation holding unit 2A and directly drives the rotation holding unit 2A. The range of the rotational speed is set to a range similar to that of the drive unit 4.
Further, the drive unit 4A is electrically connected to the control unit 6, and based on a control signal from the control unit 6, it is possible to control rotation start and stop and to control the rotation speed.

In the thin film deposition apparatus 1A, the measurement light L ₀ is irradiated toward the deposition target object 50 held by the chuck 2a of the rotary holding unit 2A to the point P on the deposition surface 50a, deposition surface 50a on The amount of reflected light from the film forming material 11 is measured.
For this reason, the optical fiber 10 and the light source 9 in the present embodiment are disposed above the film formation target body 50 held by the rotation holding unit 2A. Then, a lighting lens 20 for the measuring light L ₀ emitted from the fiber end face 10a (not shown in FIG. 7) of the optical fiber 10 is condensed to form an illumination light beam to the distal end side of the optical fiber 10.
The illumination lens 20 is arranged with its position adjusted so that the center of the illumination light beam is directed toward the point P.
In addition, the light receiving lens 8 in the present embodiment is arranged so as to be coaxial with the reflection direction of the reflected light of the illumination light beam reflected around the point P.
7 is a schematic diagram, the measurement light L ₀ with respect to the film formation surface 50a is drawn with an exaggerated incident angle, but the incident angle is set to a size close to 0 °, for example, within ± 5 °. ing. For this reason, in this embodiment, the angle dependence of the reflection angle can be ignored in the reflectance measurement of the film formation surface 50a.

Next, the operation of the thin film deposition apparatus 1A will be described with a focus on the thin film deposition method of the present embodiment, focusing on differences from the first embodiment.
FIG. 8 is a graph for explaining the target value of the optical characteristic value in the thin film deposition apparatus according to the second embodiment of the present invention. In FIG. 8, the horizontal axis represents wavelength (nm), and the vertical axis represents reflectance (%).

  In order to form a thin film of the film forming material 11 on the film formation surface 50a by the thin film forming apparatus 1A, in accordance with the flowchart shown in FIG. Film formation is performed by executing each step of S6. Hereinafter, a description will be given centering on differences from the first embodiment.

First, in step S1 of the embodiment, by holding the HiNarumakutai 50 on the spin holder 2A, the measuring light L ₀ is an illumination light beam formed by the emitted illumination lens 20 from the optical fiber 10, HiNaru The point P on the film 50 is irradiated, the reflected light is collected by the light receiving lens 8, guided to the control unit 6 by the optical fiber 7, and the amount of received light is measured by the photometric unit 13.
In the present embodiment, for using a change in reflectance at the deposition surface 50a, the reflectivity of the deposition surface 50a R _lambda in the same manner as in the first embodiment above formula (2), (3) The spectral light amount of the measurement light reflected by the film formation surface 50a is divided by ( _Rλ / 100) to obtain a reference light amount for each wavelength. Then, the reference light quantity is stored in the storage unit 15. Thus, in this embodiment, since the photometry part 13 is equipped with the spectrometer, the reference light quantity memorize | stores the spectral light quantity for every wavelength.
The measurement of the reference light quantity is preferably performed for each film formation as in the first embodiment because the measurement of the reference light quantity changes due to the change in the light quantity of the light source 9 over time even when film formation is performed under the same conditions.

  Step S2 of the present embodiment is the same as step S2 of the first embodiment.

  Next, step S3 of the present embodiment is the same as step S3 of the first embodiment, except that the control unit 14 sends a control signal for starting driving to the drive unit 4A.

Next, in step S4 of this embodiment, a reflectance is measured as an optical characteristic value.
The control unit 14 sends a control signal for starting reflectance measurement to the photometric unit 13 after sending a control signal for starting driving to the drive unit 4A. Thereby, the photometry unit 13 repeats the reflectance measurement at a specific wavelength at a predetermined sampling time until a control signal for stopping the measurement is transmitted from the control unit 14.
In the example of this embodiment, the reflectance is calculated by dividing the received light amount at λ ₁ = 520 (nm) measured by the spectrophotometer of the photometric unit 13 by the reference light amount stored in the storage unit 15, and sequentially controlling To the unit 14.
When the reflectance is sent to the control unit 14, step S4 ends, and the process proceeds to step S5 of the present embodiment.

Since the spectral reflectance when the thin film having the target film thickness t ₀ is formed on the deposition surface 50 a by the film forming material 11 is 100% with the spectral transmittance, the spectral reflectance is shown in FIG. It is like the curve 101 of the graph.
That is, the curve 101 has a transmittance of 3.9% at a wavelength of 370 nm, the reflectivity monotonously decreases from the wavelength of 370 nm toward the wavelength of 520 nm (= λ ₁ ), and a minimum reflectivity of 0% at the wavelength of 520 nm. The reflectance is monotonously increased from 520 nm toward the wavelength of 750 nm, and is a downwardly convex smooth curve with a transmittance of 2.1% at the wavelength of 750 nm.
As described above, the thin film having the target film thickness t ₀ of the film forming material 11 is an antireflection film for the wavelength of 520 nm, as in the first embodiment.
If the thickness of the thin film deviates from the target film thickness t ₀ , the curve 101 shifts as described in the first embodiment, so that the reflectance at the wavelength λ ₁ and the film forming material 11 are changed. There is a corresponding relationship with the film thickness.
Therefore, as in the case of the first embodiment, the film thickness corresponding to ± 2% of the target film thickness t ₀ when the reflectance is 0% to 0.025% from the simulation result of the spectral reflectance. You can see that it is in range. In practice, it is sufficient to determine whether the upper limit value is 0.025% or less.

Next, in step S5 of the present embodiment, the first measurement is performed except that the reflectance measurement result sent from the photometry unit 13 to the control unit 14 is compared with the reflectance target value stored in the storage unit 15. This is the same step as step S5 of the embodiment.
The time required for forming the thin film is the same as that in the first embodiment because the material of the film forming material 11 and the rotational speed of the drive unit 4A do not change.
Therefore, in the present embodiment, the specific wavelength that takes the minimum value of the reflectance is the wavelength of the measurement light L ₀ , the lower limit value of the target numerical range is the minimum value of the reflectance, and the upper limit value is higher than the minimum value of the reflectance. This is an example when a large reflectance is set. When determining in the vicinity of such a minimum value, it is sufficient to determine that it is below the upper limit value.

  Step S6 of the present embodiment is the same as step S6 of the first embodiment, except that the control unit 14 sends a control signal for stopping driving to the drive unit 4A.

When step S6 is completed and the rotation of the rotation holding unit 2 is stopped, a necessary curing process or the like is performed according to the material of the film forming material 11 as in the first embodiment.
This is the end of the thin film formation method of the present embodiment.

  The thin film deposition apparatus 1A of the present embodiment can deposit a thin film of the deposition material 11 in the same manner as the thin film deposition apparatus 1 of the first embodiment when the reflectance is adopted as the optical measurement value. It is an example. For this reason, similarly to the thin film forming apparatus 1, when forming a thin film by a wet process, it is possible to suppress variations in film thickness due to repeated film formation.

Further, in the reflectance measurement, since it is not necessary to arrange the optical fiber 10 or the like that irradiates the measurement light L ₀ on the back surface 50b side, the shape in which the optical fiber 10 such as the through hole 2b is arranged in the rotation holding portion 2A. Measurement can be performed without providing.
For this reason, the apparatus configuration of the thin film deposition apparatus 1A is simplified. Further, direct rotation of the rotation holding unit 2A is facilitated, and downsizing is possible.
In addition, since the measurement light L ₀ is irradiated to the film formation surface 50 a side, even if the position is blocked by the rotation holding unit 2 A when viewed from the back surface 50 b side, such as the outer peripheral side of the film formation surface 50 a, the reflectance Can be measured. For this reason, the freedom degree of selection of the measurement position of reflectance increases.
Moreover, in the reflectance measurement, the optical characteristic value can be measured without being affected by the optical characteristic of the back surface 50b. For example, even when the optical characteristic value of the back surface 50b varies, the optical characteristic of the thin film can be accurately measured. can do.

[Modification]
Next, a thin film deposition method according to a modification of this embodiment will be described.
The thin film deposition method of this modification is a modification of the determination step in the thin film deposition method of the second embodiment.
In this modification, in the determination step, not only the optical characteristic value for one specific wavelength is compared with the target value, but the reflectance spectrum measured in step S4 is set as a distribution tolerance set in advance. In this method, it is determined whether or not it is within the range.
The distribution allowable range is given, for example, by setting a target value for each optical characteristic value for two or more wavelengths. Wavelength setting an allowable range, and the number of wavelengths to be used can be appropriately set according to the shape of the spectrum in the target film thickness t _0. Since the photometry unit 13 measures the spectral spectrum, the wavelength used for the measurement can be freely selected within the range of the measurement resolution and the range of the measurement wavelength range.
In addition, the wavelength range for setting the distribution allowable range can be appropriately set according to the shape of the spectrum and the wavelength range used for the thin film. For example, in the case of a thin film used in the visible wavelength region, it is preferable to set the wavelength range included in the visible wavelength region, for example, in the range of 400 nm to 700 nm.

For example, in a spectral spectrum such as the curve 101 shown in FIG. 3, when seven wavelengths of 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, and 700 nm are used as wavelengths for determination, the film thickness is set to the target film thickness t _0. In order to achieve ± 2%, a reflectance target value as shown in Table 1 below may be set.

In step S <b> 4 according to this modification, the photometry unit 13 calculates spectral spectrum data as the reflectance and sends it to the control unit 14.
In step S5, the control unit 14 proceeds to step S6 when all of the reflectances by the seven wavelengths used for the determination have reached the reflectance target values in Table 1 above. Otherwise, the control unit 14 proceeds to step S4. Migrate to

  According to the method of this modification, since target values of optical characteristic values for a plurality of wavelengths over a specific wavelength range are given, it is more reliably determined that the target film thickness corresponding to the spectroscopic optical characteristics has been reached. Can do. Moreover, since the shape itself of the spectral optical characteristics of the thin film can be verified, it can be simultaneously confirmed that the spectral optical characteristics of the formed thin film are within an allowable range. For this reason, quality control of the film thickness formed becomes easy.

[Third Embodiment]
A thin film deposition apparatus according to a third embodiment of the present invention will be described.
FIG. 9 is a schematic diagram showing the configuration of a thin film deposition apparatus according to the third embodiment of the present invention. FIG. 10 is a schematic plan view showing the relationship between the film formation target formed by the thin film deposition apparatus according to the third embodiment of the present invention and the measurement position.

The thin film deposition apparatus 1B of the present embodiment is an example in the case where the optical characteristic values are measured at two places having different distances from the center O of the film formation target 50. As shown in FIG. A light source 9B, an optical fiber 10B, a light receiving lens 8B, and an optical fiber 7B are added to the thin film deposition apparatus 1 of the embodiment, and a control unit 6B is provided instead of the control unit 6.
Below, it demonstrates centering on a different point from the said 1st Embodiment. The film forming material 11, the film formation target 50, the conditions of the film thickness to be formed, and the like will be described using the same example as that used in the first embodiment.

Source 9B, an optical fiber 10B, the light receiving lens 8B, the optical fiber 7B, the distance with respect to the center O of the deposition material 50 on the deposition surface 50a _D 2/2 (provided _{that, 0 <D 2 <D 1} ) Is an apparatus portion for measuring transmittance at a point P _B separated by a distance, and has the same configuration as the light source 9, the optical fiber 10, the light receiving lens 8, and the optical fiber 7 of the first embodiment, respectively. Only the location is different.
In the present embodiment, as an example, D ₂ = 10 (mm). Further, the position in the circumferential direction of the point P _B can be set as appropriate, but in the present embodiment, as an example, the position is set at a position facing the point P across the center O.
Therefore, the position in plan view of the fiber end face 10a of the optical fiber 10B, as shown in FIG. 10, the center of the fiber end faces 10a, is set at a position that overlaps at point P _B and the vertical direction.
The light receiving lens 8B is arranged so that the optical axis of the light receiving lens 8B is aligned with the vertical axis passing through the point P _B on the film formation surface 50a, and the fiber end surface 10a of the optical fiber 10B and the light receiving lens 8B. Are arranged opposite to each other with the film formation target 50 held by the rotation holding unit 2 interposed therebetween.
The light source 9 </ b> B is disposed at an appropriate position on the lower side of the rotation holding unit 2 and away from the light source 9.
The optical fiber 7B is a light guiding unit that guides the light collected by the light receiving lens 8B to the control unit 6B. One fiber end face is disposed at the light collecting position of the light receiving lens 8B, and the other fiber end face is controlled. The unit 6B is connected to a later-described photometric unit 13B (see FIG. 3).

  Hereinafter, the light source 9, the optical fiber 10, the light receiving lens 8, and the optical fiber 7 may be referred to as a first measurement optical system, and the light source 9B, the optical fiber 10B, the light reception lens 8B, and the optical fiber 7B may be referred to as a second measurement optical system.

The control unit 6B is obtained by changing the control unit 6 in order to perform the transmittance measurement by the second measurement optical system at the point P _B in addition to the transmittance measurement by the first measurement optical system at the point P. As shown in FIG. 3, a photometric unit 13B and a control unit 14B are provided in place of the photometric unit 13 and the control unit 14 of the first embodiment.
The light metering unit 13B can perform the same transmittance calculation as that of the light metering unit 13 independently of the light amount measurement of light guided from the optical fibers 7 and 7B and the transmittance calculation, respectively. .
The control unit 14B performs on / off control of the light source 9B in addition to the light source 9, and compares the two transmittances transmitted from the photometry unit 13B with the target values of the transmittances stored in the storage unit 15, When both of the two transmittances sent from the photometry unit 13B reach the target value, the driving by the driving unit 4 is stopped.

  In order to form a thin film of the film forming material 11 on the film formation surface 50a by the thin film forming apparatus 1B, the reference light amount of the first measurement optical system is measured in advance as in the first embodiment. In addition, the reference light quantity of the second measurement optical system is measured and stored in the storage unit 15 by the photometric unit 13B.

After the measurement of the reference light amount, film formation is performed by executing steps S1 to S6 in substantially the same manner as in the first embodiment according to the flowchart shown in FIG.
The difference from the first embodiment is only that two transmittances are measured corresponding to two locations by the first measurement optical system and the second measurement optical system. For this reason, description of step S1, S2, S3, S4 of this embodiment is abbreviate | omitted.

In step S5 of the present embodiment, the control unit 14B compares the two transmittances transmitted from the photometry unit 13B with the transmittance allowable range that is the target numerical value range stored in the storage unit 15, and both transmissions. When the rate is within the target numerical value range, the process proceeds to step S6.
If any transmittance is outside the target numerical value range, the process proceeds to step S4.

Step S6 of the present embodiment is the same as step S6 of the first embodiment.
When step S6 is completed and the rotation of the rotation holding unit 2 is stopped, a necessary curing process or the like is performed according to the material of the film forming material 11 as in the first embodiment.
This is the end of the thin film formation method of the present embodiment.

  The thin film deposition apparatus 1B of the present embodiment measures a plurality of transmittances whose measurement positions are different in the radial direction of rotation, and stops rotation when these transmittances all reach a target value. As compared with the case of the single location, variation due to the location of the film thickness can be more reliably suppressed. For this reason, the accuracy of the film thickness can be improved.

[Fourth Embodiment]
A thin film deposition method according to the fourth embodiment of the present invention will be described.
FIG. 11: is typical sectional drawing which shows an example of the optical element manufactured using the thin film film-forming method concerning the 4th Embodiment of this invention. FIG. 12 is a flowchart for explaining a thin film deposition method according to the fourth embodiment of the present invention. 13, 14, and 15 show target values of optical characteristic values at the time of forming the first layer, the second layer, and the third layer in the thin film forming method according to the fourth embodiment of the present invention, respectively. It is a graph for demonstrating. In each figure, the horizontal axis represents wavelength (nm) and the vertical axis represents reflectance (%).

The thin film deposition method of the present embodiment is a method of depositing a multilayer thin film on the deposition surface of the deposition target using the thin film deposition apparatus 1A of the second embodiment.
FIG. 11 shows a cross-sectional structure of a flat glass element 60 which is an example of an optical element manufactured by this method.
The flat glass element 60 includes a first thin film layer 11a, a second thin film layer 11b, in order from the film formation surface 50a, with one surface of the film formation object 50C, which is a glass substrate having a diameter of 25 mm, being a film formation surface 50a. This is a member in which the third thin film layer 11c is laminated. The first thin film layer 11a, the second thin film layer 11b, and the third thin film layer 11c are formed by spin-coating liquid film forming materials 11A, 11B, and 11C (see FIG. 7), respectively, and then curing. It is.
In the present embodiment, the first thin film layer 11a, the second thin film layer 11b, and the third thin film layer 11c form an antireflection film with a reflectance of, for example, 0.5% or less in a wavelength range of 420 nm to 680 nm. is doing.

To manufacture such a planar glass element 60, in this embodiment, as HiNarumakutai 50C, S-BSL7; adopts (trade name OHARA _Ltd., n d = 1.52).
Further, as the materials of the film forming materials 11A, 11B, and 11C, Ogsol EA-F5503 (trade name; manufactured by Osaka Gas Chemical Co., Ltd., n ₅₂₀ = 1.62) and trimethylolpropane triacrylate containing titanium oxide, respectively. (N ₅₂₀ = 1.95), a polymerizable compound coating agent containing hollow silica similar to that in the first embodiment is employed.
Assuming that the target film thicknesses of the film forming materials 11A, 11B, and 11C are t _0A , t _0B , and t _0C , t _0A = 78.1 (nm), t _0B = 131.2 (nm), and t _0C = 95. 0 (nm). Further, the allowable range of film thickness is ± 2% for each target film thickness t _0A , t _0B , and t _0C .

The thin film forming method of the present embodiment is a method of sequentially performing steps S10 to S15 shown in FIG.
Step S10 is a film forming process for forming a thin film of the film forming material 11A on the film forming surface 50a of the film forming body 50C. This thin film is formed to a film thickness of ± 2% of the target film thickness _t0A .
This step is the step shown in FIG. 4 using the film formation target 50C and the film formation material 11A in place of the film formation target 50 and the film formation material 11 in the thin film formation method of the second embodiment. This is a step of performing S1 to S6. The following briefly describes the differences from the second embodiment.

The amount of the film forming material 11A dropped in step S2 was 0.1 mL.
The rotational speed of the drive unit 4A in step S3 was set to 5000 rpm.
The target value of the reflectance in step S5 was set to a target value corresponding to the target film thickness _{t0A of the} film forming material 11A and its allowable range.
The target value is set based on the spectral reflectance characteristics when the film forming material 11A having the target film thickness _t0A is formed on the film formation surface 50a as shown by the curve 102 in FIG.
A curve 102 has a maximum value of 5.55% reflectance at a wavelength of 350 nm, a wavelength of 520 nm (= λ ₁ ), a reflectance of 6.4944%, and a reflectance of 6.02% at a wavelength of 750 nm. It is a smooth curve convex upward.
In such a spectral reflectance characteristic, the target value, with the reflectance of the wavelength lambda _1, may be set to 6.493% or more.
For this reason, in step S4 of this process, the photometry unit 13 is set to send the reflectance of the wavelength λ ₁ to the control unit 14.

  When this step was performed in the above example, the time until the reflectance reached the target value was about 8 seconds from the start of the rotational drive. For this reason, step S6 was performed about 8 seconds after starting the rotational drive. Thereby, step S10 is completed.

Next, step S11 is performed. This step is a curing step in which the film forming material 11A is cured to form the first thin film layer 11a.
In the example of the present embodiment, after the rotation holding unit 2A is stopped, the film formation target 50C is irradiated with ultraviolet light (UV light) having a wavelength of 365 nm and an illuminance of 1000 mJ / cm ^{2 with} a high-pressure mercury lamp (SP-9 manufactured by USHIO INC.). And let it harden.
Above, step S11 is complete | finished.

Next, step S12 is performed. This step is a film forming process for forming a thin film of the film forming material 11B on the first thin film layer 11a of the film formation target 50C on which the first thin film layer 11a is formed. This thin film is formed to a film thickness of ± 2% of the target film thickness _t0B .
In this thin film deposition method of the second embodiment, this step replaces the deposition target 50 and the deposition material 11 with the deposition target 50C and the deposition material 11B on which the first thin film layer 11a is formed. Is a step of performing steps S1 to S6 shown in FIG. Therefore, the film formation surface 50a in the description of the second embodiment is read as the upper surface of the first thin film layer 11a. The following briefly describes the differences from the second embodiment.

The amount of the film forming material 11B dropped in step S2 was 0.1 mL.
The rotational speed of the drive unit 4A in step S3 was 4500 rpm.
The target value of the reflectance in step S5 was a target value corresponding to the target film thickness _{t0B of the} film forming material 11B and its allowable range.
The target value is set based on the spectral reflectance characteristics when the film forming material 11B having the target film thickness _{t0B is formed} on the first thin film layer 11a as shown by the curve 103 in FIG.
The curve 103 has a minimum value of 9.59% at a wavelength of 420 nm, a reflectance of 6.4944% at a wavelength of 520 nm (= λ ₁ ), and a reflectance of 9.91% at a wavelength of 680 nm. It is a smooth curve convex downward.
In such a spectral reflectance characteristic, the target value, with the reflectance of the wavelength lambda _1, may be less 6.520%.
Therefore, in step S3 of the present process, the photometry unit 13 is in a setting for transmitting the reflectivity of the wavelength lambda ₁ to the control unit 14.

  When this step was performed in the above example, the time until the reflectance reached the target value was about 9 seconds from the start of the rotational drive. For this reason, step S5 was performed about 9 seconds after starting the rotational drive. Thereby, step S12 is completed.

Next, step S13 is performed. This step is a curing process in which the film forming material 11B is cured to form the second thin film layer 11b.
In the example of the present embodiment, after the rotation holding unit 2A is stopped, the film formation target 50C is cured by irradiating ultraviolet rays having a wavelength of 365 nm and an illuminance of 1000 mJ / cm ^{2 with} a high-pressure mercury lamp (SP-9 manufactured by USHIO INC.). .
Above, step S13 is complete | finished.

Next, step S14 is performed. This step is a film forming process for forming a thin film of the film forming material 11C on the second thin film layer 11b of the film formation target 50C on which the first thin film layer 11a and the second thin film layer 11b are formed. This thin film is formed to a film thickness of ± 2% of the target film thickness _t0C .
In this thin film deposition method of the second embodiment, this step is performed by replacing the deposition target 50 and the deposition material 11 with the first thin film layer 11a and the second thin film layer 11b. In this process, steps S1 to S6 shown in FIG. 4 are performed using 50C and the film forming material 11C. Therefore, the film formation surface 50a in the description of the second embodiment is read as the upper surface of the second thin film layer 11b. The following briefly describes the differences from the second embodiment.

The amount of the film forming material 11C dropped in step S2 was 0.1 mL.
The rotational speed of the drive unit 4A in step S3 was 3000 rpm.
The target value of the reflectance in step S5 was a target value corresponding to the target film thickness _{t0C of the} film forming material 11C and its allowable range.
The target value is set based on the spectral reflectance characteristics when the film forming material 11C having the target film thickness t _{0C is formed} on the second thin film layer 11b as shown by the curve 104 in FIG.
The curve 104 has a reflectance of 2.84% at a wavelength of 380 nm, decreases monotonously toward a wavelength of 440 nm (= λ ₂ ), takes a local minimum value of a reflectance of 0.0302% at a wavelength λ ₂ , and increases. Then, a maximum value of reflectivity of 0.1916% was obtained at a wavelength of 540 nm (= λ ₂ ), and a minimum value of a reflectivity of 0.0222% was taken at a wavelength of 620 nm (= λ ₄ ). Turning to an increase, it is a smooth W-shaped curve with a reflectance of 1.43% at a wavelength of 750 nm.
In such spectral reflectance characteristics, the target value may be 0.080% or less in terms of the reflectance at the wavelengths λ ₂ and λ ₃ .
For this reason, in step S3 of this process, the photometry unit 13 is set to transmit the reflectances of the wavelengths λ ₂ and λ ₃ to the control unit 14.

  When this step was performed in the above example, the time until the reflectance reached the target value was about 10 seconds from the start of rotation driving. For this reason, step S5 was performed about 10 seconds after starting the rotational drive. Thereby, step S14 is completed.

Next, step S15 is performed. This step is a curing step in which the film forming material 11C is cured to form the third thin film layer 11c.
In the example of the present embodiment, after the rotation holding unit 2A is stopped, the film formation target 50C is removed, and is put into a drying furnace heated in advance to 200 ° C. for 10 minutes to be cured.
Above, step S15 is complete | finished.
In this way, the flat glass element 60 can be manufactured.

  According to the thin film formation method of this embodiment, even if it is a multilayer thin film, the film formation process and the curing process are sequentially performed for each layer, and each film formation process is performed in the same manner as in the second embodiment. It can suppress that the film thickness of the thin film of each layer varies. Therefore, it is possible to suppress variations in film thickness as a whole of the multilayer thin film and variations in optical characteristics of the thin film.

  In the above description, the light source 9 is white light and the photometric unit 13 is configured to include a spectrophotometer. However, when the wavelength light used for optical measurement is determined in advance. May be configured to include one or a plurality of monochromatic light sources corresponding to the wavelength and a light receiving element.

  In the above description, the case where the film forming material is cured by heating in a drying furnace and the case where the film forming material is cured by irradiation with UV light have been described. However, the curing method is appropriately set according to the characteristics of the film forming material. be able to. In the case of a film forming material that cures at room temperature, the curing step can be omitted.

  In the description of the modified example of the second embodiment, the example in which a plurality of wavelengths having a certain wavelength interval is used as the wavelength used for the determination has been described. The interval may be appropriately increased or decreased. Alternatively, the entire spectral spectrum shape may be set as a determination target with a wavelength interval equal to the spectral spectrum resolution.

  In the above description, it is described that the deposition target is rotated in Step S3. However, the measurement of the optical characteristics only needs to be able to determine the stop timing of the rotation of the deposition target. However, what is necessary is to be performed at least between steps S3 and S5. Therefore, the optical characteristic measurement itself may be continuously performed before step S3 is performed.

  Further, in the description of the second embodiment, the example in which the configuration in which the through hole 2b is deleted from the rotation holding unit 2 as the rotation holding unit 2A has been described, but if it does not affect the reflectance measurement, It is good also as a structure provided with the through-hole 2b. That is, the configuration composed of the rotation holding unit 2A and the drive unit 4A in the second embodiment is composed of the rotation holding unit 2, the drive unit 4, and the drive transmission unit 3 as in the first embodiment. Also good.

Moreover, all the components described in the above embodiment can be implemented by being appropriately combined or deleted within the scope of the technical idea of the present invention.
For example, the light source 9, the optical fiber 10, and the illumination lens 20 in the second embodiment are added to the configuration of the first embodiment, and the transmittance measurement and the reflectance measurement are performed as necessary. It is good also as a structure which switches or performs simultaneously.

DESCRIPTION OF SYMBOLS 1, 1A Thin film formation apparatus 2, 2A Rotation holding part 3 Drive transmission part 4, 4A Drive part 5 Material supply part 5a Material dripping part 6 Control unit 7, 10 Optical fiber (optical characteristic measurement part)
8 Receiving lens (Optical characteristics measurement unit)
9 Light source (Optical characteristics measurement unit)
11, 11A, 11B, 11C Film-forming material 13 Photometric part (optical characteristic measuring part)
14 Control unit (rotation control unit)
15 Memory 50 Deposition target body 50a Deposition surface 110 Thin film L _0, LT ₁ measurement light t ₀ , t _0A , t _0B , t _0C target film thickness

Claims (5)

A thin film forming apparatus for supplying a liquid thin film forming material onto a film forming body, and rotating the film forming body to form a thin film using the thin film forming material,
A rotation holding unit for holding and rotating the film formation body;
Of the transmittance and reflectance of the film-forming body containing the thin-film forming material, the measurement light is irradiated to the thin-film forming material thinned on the film-forming body by the rotation of the rotation holding unit. An optical property measuring unit for measuring an optical property value comprising at least one of
A rotation control unit that stops the rotation driving of the rotation holding unit when the optical characteristic value measured by the optical characteristic measurement unit reaches a target value corresponding to a target film thickness of the thin film stored in advance;
A thin film deposition apparatus comprising: The optical property measuring unit is
Irradiating multicolor light as the measurement light, and measuring the optical characteristic value at each of a plurality of wavelengths included in the multicolor light,
The rotation control unit
When the target value is stored in advance corresponding to each of the plurality of wavelengths, and all of the plurality of optical property values measured by the optical property measurement unit reach the target value corresponding to each wavelength. The thin film deposition apparatus according to claim 1, wherein the rotation driving of the rotation holding unit is stopped. The thin film deposition apparatus according to claim 2, wherein the plurality of wavelengths are included in a range of 400 nm to 700 nm. The optical property measurement unit measures the optical property value as a spectrum including a wavelength range of 400 nm to 700 nm,
The thin film deposition apparatus according to claim 2, wherein the rotation control unit stores a distribution allowable range of the spectral spectrum corresponding to a target film thickness of the thin film as the target value. A thin film forming method for forming a thin film by the thin film forming material by supplying a liquid thin film forming material onto the film forming body and rotating the film forming body,
A step of starting rotational driving of the film formation body after supplying the thin film forming material onto the film formation body;
The thin film forming material that is thinned on the film formation body is irradiated with measurement light by the rotation of the film formation body, and the transmittance and reflectance of the film formation body including the thin film formation material are measured. An optical property measuring step for measuring an optical property value consisting of at least one of them,
A determination step of determining whether or not the optical property value measured in the optical property measurement step has reached a target value corresponding to a target film thickness of the thin film stored in advance;
Stopping rotation driving of the film-forming body based on the determination that the optical characteristic value in the determination step has reached the target value;
A thin film deposition method comprising:

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