JP2001214266A - Method and apparatus for film deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film deposition apparatus and a film deposition method precisely controlling a film deposition speed. SOLUTION: The film deposition apparatus 1 as a chamber 2, a holder to hold a substrate 3 and a monitor substrate 30, a heater 5, a shutter 6, a material supply source 7, a lamp 8, a light detecting means 9 to detect a reflection light of a short wavelength (first wavelength) and a reflection light of a long wavelength (second wavelength) from the substrate 30 and a control means 11. In film depositing, a reflection rate of a short wavelength in a prescribed time is set to a target value, a film deposition speed is controlled so that the light reflection rate of a long wave length reaches the target value after the lapse of a Time Ts=Dg(Ll/Ls-1)/Vg where (Df is a film thickness of a thin film in the prescribed time, Ls is a short wavelength, Ll is a long wavelength, Vf is a target film deposition speed. Setting of a target value and adjusting of film deposition are repeated several times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a film forming apparatus and a film forming method.

[0002]

2. Description of the Related Art There is known a film forming apparatus for forming a thin film on a thin film forming object by a vapor deposition method such as a vacuum deposition method, a CVD (chemical vapor deposition) method, an ion assisted deposition method, an ion plating and a sputtering. ing.

Conventionally, the film forming speed of a film forming apparatus is controlled (adjusted) by the following quartz oscillator control method or control curve method.

A method for controlling a quartz oscillator A quartz oscillator is installed near an object on which a thin film is to be formed, and during film formation, a change in the natural frequency of the quartz oscillator on which the thin film is formed causes a change in the quartz oscillator. Find the deposition rate.
The detected film forming speed is estimated as the film forming speed on the thin film forming object, and the film forming speed is adjusted so that the detected film forming speed maintains a predetermined constant value.

Control curve method An estimated value of the refractive index in a vacuum of a thin film (estimated refractive index in a vacuum) is obtained from data obtained in the past when forming a film. Then, a time change curve (control curve) of the reflectance or the transmittance of light having a predetermined wavelength when the light is irradiated toward the thin film forming object is prepared in advance.

At the time of film formation, the light having the above-mentioned wavelength is irradiated toward a thin film forming object, its reflectance or transmittance is detected, and the film formation speed is adjusted so that the detected value follows the control curve. I do.

However, the above-described crystal oscillator control method and control curve method have the following disadvantages.

Since the temperature change of the crystal unit causes an error in the natural frequency of the crystal unit, in order to reduce the temperature change of the crystal unit,
During film formation, the crystal oscillator is cooled.

On the other hand, in film formation, an object on which a thin film is to be formed may be heated. In particular, when a thin film is formed on a thin film formation target by the CVD method, it is necessary to heat the thin film formation target to promote a chemical reaction between the thin film (film material) and the thin film formation target. Further, even when a thin film is formed on a thin film forming object by a vacuum evaporation method, the thin film forming object may be heated in order to improve the durability of the thin film.

Therefore, during the film formation, the temperature of the crystal oscillator and the temperature of the object on which the thin film is to be formed are different. For this reason, how to attach a thin film between the crystal unit and the object on which the thin film is to be formed (film forming speed)
However, this makes it impossible to accurately control the deposition rate.

Control Curve Method The refractive index in a vacuum of a thin film actually formed varies slightly depending on film forming conditions such as the temperature of a thin film forming target at the time of film formation and the degree of vacuum in a film forming apparatus. Therefore, the refractive index in vacuum may not match the expected refractive index in vacuum.

If the refractive index in vacuum does not match the expected refractive index in vacuum, the film formation rate may be adjusted so that the detected reflectance or transmittance follows the control curve. The target deposition rate cannot be obtained.

That is, when the refractive index in vacuum is lower than the expected refractive index in vacuum, the film forming rate becomes faster than the target value. Conversely, when the refractive index in vacuum is higher than the expected refractive index in vacuum, Means that the film forming speed is lower than the target value.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a film forming apparatus and a film forming method capable of accurately controlling a film forming speed.

[0015]

This and other objects are achieved by the present invention which is defined below as (1) to (10).

(1) A film forming apparatus for forming a thin film on a thin film forming object by a vapor phase film forming method, wherein a film having a first wavelength in a thin film formed on the thin film forming object during film formation. A light reflectivity or a light transmittance, and a second light longer than the first wavelength.
Optical characteristic detecting means for detecting the reflectance or transmittance of light having a wavelength of, respectively, and setting the reflectance or transmittance of the light having the first wavelength at a predetermined time to a target value, and from the predetermined time. Adjusting means for adjusting the film formation rate so that the reflectance or transmittance of the light of the second wavelength reaches the target value after a predetermined period has elapsed, and setting the target value and adjusting the film formation rate. A film forming apparatus configured to repeat the adjustment a plurality of times.

(2) The film forming apparatus according to (1), wherein the predetermined period Ts is obtained from the following equation. Ts = Df (Ll / Ls-1) / Vf where Df is the thickness of the thin film at the predetermined time, Ls
Is the first wavelength, Ll is the second wavelength, and Vf is the target film forming rate.

(3) The optical characteristic detecting means irradiates the light having the first wavelength and the light having the second wavelength toward the thin film forming surface of the thin film forming object. Means for detecting reflected light or transmitted light of the first wavelength and reflected light or transmitted light of the second wavelength from the thin film forming object, respectively, (1) wherein, based on information from the means, a reflectance or a transmittance of the light of the first wavelength and a reflectance or a transmittance of the light of the second wavelength are obtained. Or the film forming apparatus according to (2).

(4) The light projecting means irradiates light containing the first wavelength light and the second wavelength light, and the light detecting means emits light reflected from the thin film forming object. Alternatively, extraction means for extracting light of the first wavelength and light of the second wavelength from transmitted light, respectively, and first detection for detecting light of the first wavelength extracted by the extraction means Vessels,
The film forming apparatus according to (3), further including a second detector configured to detect the light having the second wavelength extracted by the extracting unit.

The number of light sources is reduced as compared with the case where a light source dedicated to light of the first wavelength emitting light of the first wavelength and a light source dedicated to light of the second wavelength emitting light of the second wavelength are used. Therefore, the configuration of the apparatus can be simplified, and there is no need for alignment for matching the irradiation position of the first wavelength light and the irradiation position of the second wavelength light. become.

(5) The thin film forming object and the thin film are each made of a dielectric material, and the refractive index of the thin film forming object and the thin film with respect to the light of the first wavelength and the refractive index of the thin film forming object and the thin film, respectively. The film forming apparatus according to any one of the above (1) to (4), wherein a difference from a refractive index for light having a wavelength of 2 is within ± 0.01. This makes it possible to more accurately and reliably control the film forming speed.

(6) The first wavelength is 400 to 150.
The film forming apparatus according to any one of (1) to (5), wherein the thickness is 0 nm, and a difference between the first wavelength and the second wavelength is 10 to 100 nm. This makes it possible to more accurately and reliably control the film forming speed.

(7) The film forming apparatus according to any one of the above (1) to (6), further comprising heating means for heating the thin film forming object.

By heating the object on which a thin film is to be formed to a predetermined temperature, the density of the obtained thin film can be improved.

(8) A film forming method characterized by forming a thin film on a thin film forming object using the film forming apparatus according to any one of the above (1) to (7).

(9) A film forming method for forming a thin film on a thin film forming object by a vapor phase film forming method, wherein a first thin film formed on the thin film forming object at a predetermined time during film formation. The reflectance or the transmittance of the light of the wavelength is detected, the detection value is set to the target value, and after the lapse of a predetermined period from the predetermined time, the reflectance of the light of the second wavelength longer than the first wavelength Alternatively, a film forming method is characterized in that control for adjusting the film forming speed is repeated a plurality of times so that the transmittance reaches the target value.

(10) The film forming method according to the above (9), wherein the predetermined period Ts is obtained from the following equation. Ts = Df (Ll / Ls-1) / Vf where Df is the thickness of the thin film at the predetermined time, Ls
Is the first wavelength, Ll is the second wavelength, and Vf is the target film forming rate.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a film forming apparatus and a film forming method according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings. In the description, “film thickness” means “film thickness” unless otherwise specified.
It means physical film thickness.

A film forming apparatus and a film forming method of the present invention are an apparatus and a method for forming a thin film on a thin film forming object by a vapor phase film forming method, respectively.

Examples of the vapor phase film forming method include a vacuum vapor deposition method, a CVD (chemical vapor deposition) method, an ion assist vapor deposition method,
Examples include ion plating and sputtering.

In the following description, a film forming apparatus (vacuum vapor deposition apparatus) for forming a thin film on a thin film forming object by a vacuum vapor deposition method and a film forming method will be described.

Further, according to the present invention, at the time of film formation, the first wavelength (short wavelength)
And the reflectance or transmittance of light of a second wavelength (longer wavelength) longer than the first wavelength is detected to adjust the film forming speed. In the description, a film forming apparatus and a film forming method for adjusting the film forming speed by detecting the reflectance will be described.

FIG. 1 is a sectional view schematically showing an embodiment in which the film forming apparatus of the present invention is applied to a vacuum evaporation apparatus.

As shown in FIG. 1, a film forming apparatus 1 includes a chamber (vacuum furnace) 2, a substrate (object for forming a thin film) 3, and a holder (holding portion) for holding a monitor substrate (object for forming a thin film) 30. 4, a heater (heating means) 5, a shutter 6,
It has a material supply source 7, a lamp (light emitting means) 8, a light detecting means 9, and a control means 11.

The pipes 14 and 15 are connected to the chamber 2. The pipe 14 is connected to the vacuum pump 12 that exhausts the atmosphere gas (inert gas, reaction gas, etc.) in the chamber 2. The pipe 15 is connected to a reaction gas cylinder 13 for introducing a reaction gas into the chamber 2. A valve 16 is mounted in the middle of the pipe 15.

The atmosphere in the chamber 2 is usually
A non-oxidizing atmosphere, for example, under a reduced pressure (vacuum) state, or an inert gas such as a nitrogen gas or an argon gas is preferable.
In this atmosphere, a small amount of reaction gas (such as oxygen gas) can be introduced from the reaction gas cylinder 13.

A holder 4 is provided above the chamber 2. The holder 4 includes a plurality of substrates (thin film forming objects) 3 on which a thin film is formed, and the same properties (equivalent) as the thin film
And a monitor substrate (object for forming a thin film) 30 on which the thin film is formed. Constituent material of the monitor substrate 30,
The shape, dimensions and the like are all equal to those of the substrate 3.

The substrate 3 and the monitor substrate 30 are preferably formed of a dielectric material. Examples of the constituent materials include various optical glasses, acrylic resins, polycarbonate resins, polyarylate resins, and the like. An optical material such as a resin material such as a polyolefin resin is exemplified.

The thin films formed on the film forming surfaces of the substrate 3 and the monitor substrate 30 are preferably made of a dielectric material.

A heater (heating means) 5 is provided between the holder 4 and the upper wall 22 of the chamber 2.

The heater 5 is used for the substrate 3 in the chamber 2,
The monitor substrate 30 and the atmosphere are heated.

When the substrate 3 and the monitor substrate 30 are made of optical glass, the substrate temperature is set to 150 to 350
It is preferable to heat and maintain the temperature at about 200 ° C.
It is more preferable to heat and hold at about 0 ° C. Thereby, the film density of the obtained thin film is improved. Also, the substrate 3
When the monitor substrate 30 is made of an optical material such as a resin, it is preferable to heat and hold the monitor substrate 30 to such an extent that the substrate is not deformed.

The temperatures of the substrate 3, the monitor substrate 30, and the atmosphere are measured by a thermocouple (not shown) installed near the heater 5, and the measured values are input to the control means 11. The control means 11 controls the heater 5 based on the measured value.
To control the drive of.

A material supply source 7 is provided on the right side of the bottom of the chamber 2 in FIG.

The material supply source 7 includes a crucible 72, an evaporation source 71 disposed (filled) in the crucible 72, and an electron gun 7.
3 is comprised. The electron gun 73 emits an electron beam having a high energy density, heats the evaporation source 71 in the crucible 72, and melts and evaporates it.

The shutter 6 is provided in the chamber 2 above the crucible 72 of the material supply source 7.

The shutter 6 has, for example, an iris structure including a plurality of blades.

The shutter 6 has a function of blocking the transfer of the material (evaporated evaporation source 7) supplied from the material supply source 7 to the film formation surface of the substrate 3 and the monitor substrate 30.

When the shutter 6 is closed (closed state), adhesion of the film material to the film forming surface of the substrate 3 and the film forming surface of the monitor substrate 30, that is, formation of a thin film (film formation) is prevented. Is done.

Conversely, when the shutter 6 is open (in the open state), it becomes possible to attach a film material to the film forming surface of the substrate 3 and the film forming surface of the monitor substrate 30, that is, to form a thin film. Become.

In the center of the bottom of the chamber 2, there is provided a window 21 made of a member having light transmissivity (for example, various kinds of glass and various kinds of resin).

The window 21 outside the chamber 2
On the lower side, a lamp (light emitting means) 8 that emits white light,
Light detection means 9 are provided respectively.

The white light includes light having a first wavelength (hereinafter, referred to as “short wavelength”) and light having a second wavelength longer than the short wavelength (hereinafter, referred to as “long wavelength”). In. The short-wavelength light and the long-wavelength light are used for controlling (adjusting) a film forming speed described later.

The difference between the refractive index for the short wavelength light and the refractive index for the long wavelength light of the substrate 3, the monitor substrate 30, and the thin films formed thereon is within ± 0.01. In particular, it is preferable that the setting is made within ± 0.005. Thereby, the peak value (maximum value and minimum value) of the reflectance of the short wavelength light and the peak value (maximum value and minimum value) of the reflectance of the long wavelength light almost coincide with each other, and the film forming speed can be more accurately determined. And it can control reliably.

The short wavelength is preferably about 400 to 1500 nm, and more preferably about 450 to 1400 nm. Also, the difference between short wavelength and long wavelength is
It is preferably about 10 to 100 nm, more preferably 15 to 95.
It is more preferably about nm. Thereby, the peak value (maximum value and minimum value) of the reflectance of the short wavelength light and the peak value (maximum value and minimum value) of the reflectance of the long wavelength light almost coincide with each other, and the film forming speed can be more accurately determined. And it can control reliably.

The light detecting means 9 includes a half mirror 91, a short-wavelength spectrometer 92 for extracting (separating) only short-wavelength light from the incident white light, and a short-wavelength light emitted from the short-wavelength spectrometer 92. Wavelength detector (first detector) 9 for detecting
3, a long-wavelength spectrometer 94 that extracts (separates) only long-wavelength light from the incident white light, and a long-wavelength detector (a second wavelength detector) that detects long-wavelength light emitted from the long-wavelength spectrometer 94. (Detector) 95.

The control means 11 is usually constituted by a microcomputer (CPU), and comprises a heater 5, a shutter 6, an electron gun 73, a lamp 8, a vacuum pump 12, and a valve 16
For example, the driving of the entire film forming apparatus 1 is controlled.

The main function of the adjusting means for adjusting the film forming speed is achieved by the control means 11.

The white light emitted from the lamp 8 is
, Travels toward the film formation surface of the monitor substrate 30, and is reflected by the monitor substrate 30. This reflected light passes through the window 21, and a part of the reflected light is reflected by the half mirror 91,
The light enters the short-wavelength spectrometer 92, and the remainder is a half mirror 91.
And enters the long-wavelength spectrometer 94.

The short-wavelength spectrometer 92 extracts only the short-wavelength light, and the short-wavelength light enters the short-wavelength detector 93.

On the other hand, in the long-wavelength spectroscope 94, only the long-wavelength light is extracted, and the long-wavelength light is extracted by the long-wavelength detector 95.
Incident on.

The short wavelength detector 93 detects short wavelength light. That is, light of a short wavelength is received, and information (detection value) corresponding to the received light amount is input to the control unit 11.

In the present embodiment, the control means 11 sets the information (detected value) and the reflectance of short-wavelength light described later to 1 (1
00%), the monitor substrate 30 before the start of film formation, the monitor substrate 30 after the start of film formation, and the monitor substrate 30. The reflectance of short-wavelength light (hereinafter, simply referred to as “short-wavelength light reflectance”) of the entire formed thin film is obtained.

On the other hand, the long wavelength detector 95 detects long wavelength light. That is, light having a long wavelength is received, and information (detection value) corresponding to the received light amount is input to the control unit 11.

In this embodiment, the control means 11 determines that the information (detected value) and the reflectance of long-wavelength light, which will be described later, are 1 (1).
00%), the monitor substrate 30 before the start of film formation, and the monitor substrate 30 and the monitor substrate 30 after the start of film formation. The reflectance of long-wavelength light (hereinafter simply referred to as “long-wavelength light reflectance”) of the entire formed thin film is obtained.

Incidentally, the half mirror 91, the short wavelength spectroscope 92 and the long wavelength spectroscope 94 constitute an extracting means.

The lamp 8, the light detecting means 9 and the control means 11 constitute an optical characteristic detecting means.

Next, control (adjustment) of the film forming speed in the film forming apparatus 1 will be described. Here, the film forming speed refers to the thickness of the thin film formed on the film forming surface of the substrate 3 and the monitor substrate 30 per unit time (the amount of the thin film formed per unit area of the film forming surface). .

FIG. 2 shows the reflectance R of short-wavelength light during film formation.
It is a graph which shows the time-dependent change (change with respect to time) of the reflectance R1 of s and long wavelength light.

First, the outline will be described. As shown in FIG. 2, the reflectance Rl of the long-wavelength light during the film formation lags behind the reflectance Rs of the short-wavelength light.

In order to set the film forming speed to the target film forming speed Vf, at the time of film forming, the reflectance of the short-wavelength light in a predetermined time is set to a target value, and from the predetermined time to a predetermined period ( (Time) The film forming speed is adjusted (changed or maintained) so that the reflectance of long-wavelength light reaches the target value after the elapse of Ts. The setting of the target value and the adjustment of the deposition rate are repeated a plurality of times (until the deposition is completed). The predetermined period T
s is obtained from the following equation (1).

Ts = Df (L1 / Ls−1) / Vf (1) where Df is the film thickness of the thin film at the predetermined time, Ls
Is a short wavelength (first wavelength), Ll is a long wavelength (second wavelength), and Vf is a target film forming speed.

That is, as shown in FIG. 2, the reflectance Rs of light having a short wavelength at a predetermined time t1 is detected (measured).
Then, the value is set to the target value Rm1, and the time Ts1 is obtained from the equation (1). Then, after the time Ts1 has elapsed from the time t1, the film forming speed is adjusted such that the reflectance R1 of the long-wavelength light reaches the target value Rm1.

Subsequently, the reflectance Rs of the short wavelength light at the time t2 is detected, the value is set to the target value Rm2, and the time Ts2 is obtained from the above equation (1). Then, after the time Ts2 has elapsed from the time t2, the film forming speed is adjusted such that the reflectance Rl of the long-wavelength light reaches the target value Rm2.

Similarly, the reflectance Rs of the short-wavelength light at the time tx is detected, the value is set to the target value Rmx, and the time Tsx is obtained from the above equation (1). Then, after the time Tsx has elapsed from the time tx, the film forming speed is adjusted so that the reflectance Rl of the long-wavelength light reaches the target value Rmx.

The film forming speed is adjusted by, for example, adjusting the power of the electron gun 73 (heating of the evaporation source 71). In the case of a film forming apparatus that forms a film by a CVD method, for example, the flow rate of a film material is adjusted. In the case of a film forming apparatus that forms a film by sputtering, for example, the sputtering power is adjusted.

By controlling the film forming speed as described above, the film forming speed can be accurately and reliably controlled.

That is, not using a quartz oscillator, not to mention the case where the substrate temperature is low, the film formation rate can be accurately controlled even when the substrate temperature is high, and the reflectance of short-wavelength light can be controlled. (Or transmittance) is adjusted to a target value to adjust the film formation rate, so that the film formation rate can be accurately controlled without being substantially affected by the change in the refractive index of the thin film in vacuum.

Next, it will be described that a film can be formed at a target film forming speed Vf by controlling the film forming speed.

For the sake of simplicity, the short wavelength is represented by Ls [n
m], the long wavelength is Ll [nm], the refractive index of the substrate 3 and the monitor substrate 30 is Ns, the refractive index of the thin film is Nf, and the thickness of the thin film is Df [nm]. The film thickness δs is represented by the following equation. δs = 4πNfDf / Ls

On the other hand, the phase thickness δl in the case of long-wavelength light
Is represented by the following equation. δl = 4πNfDf / Ll

When the phase thickness is δ, the reflectance R of light of each wavelength is expressed by the following equation (2).

R = {(1-Nf) ² (Nf + Ns) ² + (1 + Nf) ² (Nf-Ns) ² +2 (1-Nf ² ) (Nf ² -Ns ² ) cosδ｝ / ｛ (1 + N f) ² (Nf + Ns) ² + (1-Nf) ² (Nf-Ns) ² +2 (1-Nf ² ) (Nf ² -Ns ² ) cosδ｝ (2) If the phase thickness δ in the expression (2) is replaced with the phase thickness δs for light of a short wavelength, the expression (2) becomes an expression representing the reflectance Rs of the light of a short wavelength. If the phase film thickness δ in the expression (2) is replaced by the phase film thickness δ1 for light of a long wavelength, the expression (2) becomes an expression showing the reflectance R1 of the light of a long wavelength.

Here, in controlling the film forming speed in the film forming apparatus 1, the film forming speed is set to the target film forming speed Vf [n
m / sec], as described above, after Ts [seconds] from the current (predetermined time), the reflectance of the long-wavelength light is changed to the current (predetermined time) reflectance of the short-wavelength light. The film forming rate is adjusted as needed so that the reason why Ts is expressed by the above equation (1) will be described.

First, the reflectance of light of short wavelength (wavelength Ls [nm]) when the film thickness of the thin film is Ds [nm] is Rs, and the long wavelength (wavelength) when the film thickness of the thin film is Dl [nm]. Ll [n
m]), if the reflectance of the light is Rl, in order for the Rs and Rl to match, the phase thicknesses δ of the expression (2) indicating the reflectance R need only be equal to each other.

That is, Rl is the film thickness Dl [n
m] is equal to Rs when DsLl / Ls (when Dl = DsLl / Ls).

On the other hand, when the film forming speed is equal to the target film forming speed Vf [n
m / sec], Ts from the time when the film thickness of the thin film is Ds.
Assuming that Rl becomes equal to Rs after [sec], Dl becomes
It is represented by the following equation.

Dl = Ds + VfTs = DsLl / Ls By erasing Dl in the above equation and replacing Ds with the current (predetermined time) film thickness Df of the thin film, the following equation, that is, equation (1) is obtained. Ts = Df (Ll / Ls-1)
/ Vf

Next, the operation of the film forming apparatus 1 will be described. FIG.
5 is a flowchart illustrating a control operation of a control unit of the film forming apparatus 1. Hereinafter, description will be made based on this flowchart.

First, an operation for satisfying the pre-film formation conditions is started. That is, the heater 5 is operated, the substrate 3 and the monitor substrate 30 are heated, the vacuum pump 12 is operated, and the atmospheric gas in the chamber 2 is exhausted. Then, it is determined whether the pre-film formation condition is satisfied (step S).
101).

In this embodiment, the substrate temperature is 250 ° C.
The degree of vacuum in chamber 2 is 1.3 × 10 ^-3Film formation when Pa
It is assumed that the precondition is satisfied.

If it is determined in step S101 that the pre-film forming condition is satisfied, the target film forming speed Vf,
The refractive index Ns, short wavelength (first wavelength) Ls, long wavelength (second wavelength) Ll of the substrate 3 and the monitor substrate 30 and the film thickness at which the thin films formed on the substrate 3 and the monitor substrate 30 are finished (target While reading the film thickness Dend, the predicted refractive index of the thin film formed on the substrate 3 and the monitor substrate 30 is read as the refractive index Nf of the thin film (step S1).
02).

Next, the reflectance Rs of short-wavelength light is measured (step S103). Next, the reflectance Rl of the long wavelength light is measured (step S104).

Next, the power (output) of the electron gun 73 is set to a predetermined value (a value at which the deposition rate is expected to be Vf), the electron gun 73 is operated, and the evaporation source (for example, Ti
O ₂ ) 71 is started to be irradiated with the electron beam (step S105). Thereby, the evaporation source 71 in the crucible 72 is heated and evaporated.

Next, the valve 16 is opened, a reaction gas (eg, oxygen) is introduced into the chamber 2 from the reaction gas cylinder 13, and the degree of vacuum in the chamber 2 is set to 1.3 × 10 ⁻² Pa (step S106). .

Next, the shutter 6 is opened (step S1).
07). Thus, film formation is started.

Next, the peak number P of the reflectance of the short-wavelength light
s is set to 0, and the peak number Pl of the reflectance of long-wavelength light is set to 0 (step S108).

The number of peaks of the reflectance refers to the number of the maximum points (maximum values) of the reflectance during film formation and the number of the minimum points (minimum values).
Say the sum with the number of

Then, after waiting for one second, the time count value Ct is obtained.
(Second) is set to 0 (step S109).

Next, the reflectance Rs of the short-wavelength light is measured (step S110). Next, the reflectance Rl of the long-wavelength light is measured (step S111).

Next, it is determined whether or not the reflectance Rs of the short-wavelength light is equal to the reflectance Rl of the long-wavelength light (Rs = R1) (step S112).

If it is determined in step S112 that Rs = Rl, that is, the reflectance Rs of the short-wavelength light
If there is no difference between the reflectance and the reflectance R1 of the long wavelength light, the process returns to step S109, and steps S109 to S112 are executed again.

Then, in step S112, Rs =
If it is determined that the reflectance is not Rl, that is, if there is a difference between the reflectance Rs of the short wavelength light and the reflectance Rl of the long wavelength light, the peak number Ps of the reflectance of the short wavelength light is measured. And
The peak number Pl of the reflectance of the long-wavelength light is measured (step S113).

Next, the peak number P of the reflectance of the short-wavelength light
It is determined whether or not s has changed (step S11).
4).

When the reflectance of the short-wavelength light reaches the maximum point (maximum value) or the minimum point (minimum value), the number of peaks Ps increases by one, and the reflectance of the long-wavelength light increases. When reaching the maximum point (maximum value) or the minimum point (minimum value), the peak number Pl increases by one.

If it is determined in step S114 that there is no change in the number Ps of the peaks of the reflectance of the short-wavelength light,
The number of peaks Ps of the reflectance of the short wavelength light, the short wavelength Ls,
The thickness Df of the formed thin film is calculated by substituting the refractive index Ns of the substrate and the monitor substrate 30, the refractive index Nf of the thin film, and the reflectance Rs of short-wavelength light into the following equation (3) ( Step S117).

[0107]

(Equation 1)

Until the value of the refractive index Nf of the thin film is replaced in step S116, which will be described later, the predicted refractive index of the thin film read in step S102 is Nf as described above.

If it is determined in step S114 that there is a change in the peak number Ps of the reflectance of the short-wavelength light, that is, the reflectance of the short-wavelength light has a maximum point (maximum value).
Alternatively, when the number reaches the minimum point (minimum value), it is determined whether the peak number Ps is an even number (step S115).

When the peak number of the reflectivity is an odd number, that is, when the reflectivity reaches the maximum point (maximum value), COSδ in the equation (2) (where δ is the phase thickness of the thin film) Becomes 0, and the refractive index in vacuum of the thin film at that time can be accurately obtained.

If it is determined in step S115 that the peak number Ps of the reflectance of the short-wavelength light is an even number,
Step S117 described above is executed, and the thickness Df of the formed thin film is calculated.

When it is determined in step S115 that the peak number Ps of the reflectance of the short wavelength light is odd, the refractive index Ns of the substrate and the monitor substrate 30 and the reflectance Rs of the short wavelength light are determined. Is substituted into the following equation (4), and the refractive index of the thin film in vacuum at that time is calculated, and the refractive index Nf of the thin film is calculated.
Is replaced with the calculated value (step S116), and thereafter, the above-described step S117 is executed to calculate the thickness Df of the formed thin film.

[0113]

(Equation 2)

After step S117, it is determined whether or not the film thickness Df of the thin film is smaller than the film formation end thickness Dend (Df <Dend) (step S118).

In step S118, Df <Dend
When it is determined that the film thickness Df of the thin film has not reached the film formation end thickness Dend, the film formation is continued,
The reflectance Rs of the short-wavelength light at the start of the counting of the time count value Ct is set to the target value Rm of the reflectance of the long-wavelength light (Rm = Rs) (step S119).

Next, the time (evaluation time) Ts is calculated by substituting the short wavelength Ls, the long wavelength Ll, the target film forming speed Vf and the thin film thickness Df into the above equation (1) (step S).
120).

As described above, if the film forming speed is the target film forming speed Vf, when the elapsed time from the start of counting the time count value Ct reaches the evaluation time Ts, the long wavelength The light reflectance reaches its target value Rm.

In this program, the evaluation time Ts
Since the count value Ct of the time to be compared with is incremented every second, the value of the evaluation time Ts is obtained by rounding off 1/10 seconds.

Then, after waiting for one second, the time count value Ct is incremented by one (1 second) (Ct = Ct + 1).
(Step S121).

Next, the reflectance Rs of the short-wavelength light is measured (step S122). Next, the reflectance Rl of the long wavelength light is measured (Step S123).

Next, the peak number P of the reflectance of the short-wavelength light
s is equal to the peak number Pl of the reflectance of long wavelength light (P
It is determined whether or not s = P1) (step S124).

As shown in FIG. 2, when the reflectance of the short wavelength light and the reflectance of the long wavelength light are both increasing or decreasing, Ps = Pl.

On the other hand, when one of the reflectance of the short-wavelength light and the reflectance of the long-wavelength light is increasing and the other is decreasing, Ps ≠ Pl.

If it is determined in step S124 that Ps is not equal to Pl, the process returns to step S121, and steps S121 to S124 are executed again.

Then, in step S124, Ps =
If it is determined to be Pl, the reflectance R of short-wavelength light
s is larger than the reflectance Rl of long wavelength light (Rs> Rl)
It is determined whether or not (step S125).

As shown in FIG. 2, when both the reflectance of the short wavelength light and the reflectance of the long wavelength light are increasing, Rs> Rl. <
Rl.

If it is determined in step S125 that Rs> Rl, it is determined whether or not the reflectance Rl of long-wavelength light is equal to or greater than its target value Rm (Rl≥Rm) (step S126).

When it is determined in step S126 that R1 <Rm, that is, the reflectance R1 of the long-wavelength light
Does not reach the target value Rm, the step S
Returning to step 121, steps S121 and subsequent steps are executed again.

Then, at step S126, Rl ≧
If it is determined that Rm is equal to Rm, that is, if the reflectance Rl of the long-wavelength light has reached its target value Rm, the evaluation time Ts is equal to the time count value Ct (Ts = Ct). Is determined (step S128).

Note that the time count value Ct is equal to the reflectance R of short-wavelength light, which is the target value Rm for reflectance of long-wavelength light.
This is the time (period) from the time of measurement of s (at the time of setting the target value Rm) to the present time, that is, the time from the time of the measurement until the reflectance Rl of the long-wavelength light reaches the target value Rm.
In the case of Ts = Ct, the deposition rate is the target deposition rate Vf
It has become.

On the other hand, when Ts <Ct, the film forming speed is smaller (slower) than the target film forming speed Vf.

When Ts> Ct, the film forming speed is higher (faster) than the target film forming speed Vf.

If it is determined in step S128 that Ts = Ct, that is, if the film forming speed is equal to the target film forming speed Vf
In the case of, the current film forming speed is maintained, the process returns to step S109, and steps S109 and thereafter are executed again.

In step S128, Ts = C
If it is determined that it is not t, it is determined whether or not the evaluation time Ts is smaller than the time count value Ct (Ts <Ct) (step S129).

If it is determined in step S129 that Ts <Ct, that is, if the film forming speed is equal to the target film forming speed Vf
If smaller, the power of the electron gun 73 is increased by a predetermined value to increase the film forming speed. (Step S130).

In step S130, the power of the electron gun 73 is set to an appropriate value (a value at which the film forming speed is estimated to be the target film forming speed Vf) based on the difference between Ts and Ct, Ts, Ct, and the like. Set.

In step S129, Ts> C
If it is determined that it is t, that is, if the film forming speed is higher than the target film forming speed Vf, the power of the electron gun 73 is reduced by a predetermined value to decrease the film forming speed. (Step S13
1).

In step S131, the power of the electron gun 73 is set to an appropriate value based on the difference between Ts and Ct, Ts, Ct, and the like.

Further, in step S125, Rs
If it is determined that ≦ R1, it is determined whether or not the reflectance R1 of the long-wavelength light is equal to or less than its target value Rm (R1 ≦ Rm) (step S127).

When it is determined in step S127 that Rl> Rm, that is, the reflectance R1 of the long-wavelength light
Does not reach the target value Rm, the step S
Returning to step 121, steps S121 and subsequent steps are executed again.

Then, in step S127, Rl ≦
If it is determined that it is Rm, that is, if the reflectance R1 of the long-wavelength light has reached its target value Rm, the process proceeds to step S128, and the steps after step S128 are executed.

It should be noted that Df is determined in step S118.
≧ Dend, that is, the thickness Df of the thin film
Reaches the film formation end thickness Dend, the shutter 6
Is closed (step S132). Thus, the film formation is completed.

Next, a predetermined post-film formation process is performed (implementation).
(Step S133). In this step S133, for example, the driving of the electron gun 73 is stopped, and an atmosphere introduction valve (not shown) is opened to introduce the atmosphere into the chamber 2. This ends the program.

Using the film forming apparatus 1 described above, film formation was performed five times in accordance with the flowchart (program) shown in FIG. The film forming conditions and the like are as follows.

Substrate and monitor substrate: BK7 glass (refractive index: 1.52) Evaporation source: TiO ₂ reactive gas: oxygen Substrate temperature: 250 ° C. Vacuum degree before film formation: 1.3 × 10 ⁻³ Pa Vacuum degree during film formation (Degree of vacuum when oxygen is introduced): 1.3
× 10 ^-2 Pa Short wavelength (first wavelength) Ls: 650 nm Long wavelength (second wavelength) Ll: 700 nm Target film forming speed Vf: 0.4 nm / sec

FIG. 4 shows the change (5 times) of the reflectance of the short wavelength light (wavelength 650 nm) with respect to time, and FIG. 5 shows the change (5 times) of the reflectance of the long wavelength light (wavelength 700 nm) with time. Shown in

Further, a long wavelength (wavelength 7
00 nm), the actual film forming speed Vp until the reflectance Rl of the light reaches the peak, and the long wavelength (wavelength 7
00p) and the reflectance R of long-wavelength (700 nm) light until the reflectance Rl of the
Table 1 below shows the peak value of 1 and the refractive index (refractive index in vacuum) Nf of the thin film with respect to light having a long wavelength (700 nm in wavelength). The actual film forming speed Vp was obtained from the following equation.

Vf = L1 / (4NfTp) where L1 is a long wavelength (700 nm wavelength).

[0149]

[Table 1]

As shown in Table 1, the substrate temperature was relatively high (250 ° C.) and the film formation rate was stable despite the change in the refractive index of the thin film. It was confirmed that control was possible.

As described above, the film forming apparatus and the film forming method of the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part has the same function. Any configuration can be used.

For example, the present invention is not limited to the above-described vacuum vapor deposition apparatus, but a film deposition apparatus for forming a thin film by another vapor phase film deposition method (for example, CVD method, ion-assisted vapor deposition method, ion plating, sputtering, etc.). Can be applied to

Further, in the film forming apparatus of the present invention, at the time of film formation, the transmittance of light of the first wavelength (short wavelength) in the thin film formed on the object on which the thin film is to be formed is determined based on the transmittance of the first wavelength. It may be configured to detect the transmittance of light having a long second wavelength (long wavelength) and adjust the film forming speed.

In this case, at the time of film formation, the optical property detection means detects the thin film formed on the thin film forming object.
The transmittance of the light of the first wavelength and the transmittance of the light of the second wavelength are respectively detected, and the transmittance of the light of the first wavelength at a predetermined time is set to a target value by the adjusting means. The film forming speed is adjusted so that the transmittance of the light of the second wavelength reaches the target value after a lapse of a predetermined period from the predetermined time. The setting of the target value and the adjustment of the film forming speed are repeated a plurality of times.

In the present invention, the light projecting means is, for example,
A first light emitting unit that emits only light of the first wavelength and a second light emitting unit that emits only light of the second wavelength may be used.

[0156]

As described above, according to the film forming apparatus and the film forming method of the present invention, the film forming speed can be accurately and reliably controlled.

That is, even when the temperature of the thin film forming object is high, the film forming speed can be accurately controlled.
Since the reflectance or transmittance of the light of the second wavelength is set to a target value, and the film forming rate is adjusted so that the reflectance or transmittance of the light of the second wavelength reaches the target value after a predetermined period, the thin film Even if the refractive index fluctuates, the film forming speed can be accurately controlled.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment in which a film forming apparatus of the present invention is applied to a vacuum evaporation apparatus.

FIG. 2 is a graph showing the change over time (change with time) of the reflectance Rs of short-wavelength light and the reflectance R1 of long-wavelength light during film formation in the present invention.

3 is a flowchart showing a control operation of a control unit of the film forming apparatus shown in FIG.

FIG. 4 is a graph showing a change in reflectance of light having a short wavelength (wavelength 650 nm) with respect to time (5 times) in the present invention.

FIG. 5 is a graph showing a change (5 times) of reflectance of long-wavelength light (wavelength 700 nm) with respect to time in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film-forming apparatus 2 Chamber 21 Window 22 Top wall 23 Bottom wall 3 Substrate 30 Monitor substrate 4 Holder 5 Heater 6 Shutter 7 Material supply source 71 Evaporation source 72 Crucible 73 Electron gun 8 Lamp 9 Light detection means 91 Half mirror 92 Short wavelength spectroscopy Instrument 93 Short wavelength detector 94 Long wavelength spectrometer 95 Long wavelength detector 11 Control means 12 Vacuum pump 13 Reaction gas cylinder 14, 15 Pipeline 16 Valve S101 to S133 Step

Claims (10)

[Claims] 1. A film forming apparatus for forming a thin film on a thin film forming object by a vapor phase film forming method, wherein a light of a first wavelength in a thin film formed on the thin film forming object during film formation. Optical characteristic detecting means for detecting the reflectance or transmittance of the first wavelength and the reflectance or transmittance of light of the second wavelength longer than the first wavelength, respectively; Setting the reflectance or the transmittance to a target value and adjusting the film forming rate so that the reflectance or the transmittance of the light of the second wavelength reaches the target value after a lapse of a predetermined period from the predetermined time. Means for setting the target value and adjusting the film forming rate a plurality of times. 2. The film forming apparatus according to claim 1, wherein the predetermined period Ts is obtained by the following equation. Ts = Df (Ll / Ls-1) / Vf where Df is the thickness of the thin film at the predetermined time, Ls
Is the first wavelength, Ll is the second wavelength, and Vf is the target film forming rate. 3. The light projecting means for irradiating the light of the first wavelength and the light of the second wavelength toward the thin film forming surface of the thin film forming object, respectively. And light detecting means for respectively detecting reflected light or transmitted light of the first wavelength and reflected light or transmitted light of the second wavelength from the thin film formation target, and the light detecting means 3. The apparatus according to claim 1, wherein the reflectance or the transmittance of the light of the first wavelength and the reflectance or the transmittance of the light of the second wavelength are determined based on the information from. 3. The film forming apparatus according to item 1. 4. The light projecting means irradiates light containing the first wavelength light and the second wavelength light, and the light detecting means reflects reflected light from the thin film forming object or Extraction means for extracting the light of the first wavelength and the light of the second wavelength from the transmitted light, respectively, and a first detector for detecting the light of the first wavelength extracted by the extraction means 4. The film forming apparatus according to claim 3, further comprising: a second detector configured to detect the light having the second wavelength extracted by the extracting unit. 5. 5. The thin film forming object and the thin film,
Each of which is made of a dielectric material, wherein the difference between the refractive index of the thin film forming object and the thin film for the light of the first wavelength and the refractive index for the light of the second wavelength is ± 0.01. The film forming apparatus according to claim 1, wherein: 6. The method according to claim 1, wherein the first wavelength is 400 to 1500 nm.
And the difference between the first wavelength and the second wavelength is 10
The film forming apparatus according to claim 1, wherein the thickness is from 100 to 100 nm. 7. The film forming apparatus according to claim 1, further comprising heating means for heating the object on which the thin film is formed. 8. A film forming method comprising forming a thin film on a thin film forming object using the film forming apparatus according to claim 1. 9. A film forming method for forming a thin film on a thin film forming object by a vapor phase film forming method, wherein a first time of a thin film formed on the thin film forming object at a predetermined time during film formation. Detecting the reflectance or transmittance of light having a wavelength, setting the detected value to a target value, and the reflectance or light of the second wavelength longer than the first wavelength after a lapse of a predetermined period from the predetermined time or A film forming method, wherein a control for adjusting a film forming speed such that a transmittance reaches the target value is repeated a plurality of times. 10. The film forming method according to claim 9, wherein the predetermined period Ts is obtained from the following equation. Ts = Df (Ll / Ls-1) / Vf where Df is the thickness of the thin film at the predetermined time, Ls
Is the first wavelength, Ll is the second wavelength, and Vf is the target film forming rate.