JPS5852475A - Method and device for monitoring and measuring thin film in thin film former - Google Patents

Abstract

PURPOSE:To control the optical characteristics of thin films efficiently in the stage of forming said films by vacuum deposition on the surface of a substrate while transferring the substrate with respect to vapor sources and by measuring the spectral characteristics of the the films simultaneously with respect to many wavelengths which include or do not include specific wavelengths. CONSTITUTION:The light from a light projector 23 of an optical monitoring device 34 is reflected by a semitransparent mirror 24, is reflected by the thin film on a substrate 14 and passes through the window 26 and the mirror 24 backward. This light is split to three luminous fluxes by semitransparent mirrors 35a, b and a reflecting mirror 5c. The split luminous fluxes pass through narrow band filters 36a-c of lambdaa-c transmission wavelengths respectively and enter photodetectors 25a-c. After the output signals from the photodetectors 25a-c are amplified with amplifiers 37a-c for supervising of film thicknesses, these signals are inputted to a multipens recorder 29 for displaying the outputs for monitoring the film thicknesses. The recorder 29 constitutes the monitoring part for film thicknesses together with a control board 28, and in said monitoring part, monitoring and controlling are accomplished by conventional methods.

Description

DETAILED DESCRIPTION OF THE INVENTION In this invention, when a substrate is transferred to an evaporation source and a thin film is formed on the surface of the substrate by vacuum evaporation NK, the reflectance or transmittance of the thin film for light of a specific wavelength is determined. The present invention relates to a method for monitoring the thickness of a thin film based on changes. This invention also. Light is projected onto the thin film from a projector into a thin film forming apparatus in which an evaporation source and a mechanism for transferring the substrate to the source are placed in a vacuum chamber so that a thin film can be formed by vacuum evaporation on the surface of the substrate being transferred. The present invention also relates to a device equipped with an optical monitor that extracts light of a specific wavelength for film thickness monitoring from the light transmitted through or reflected by the optical monitor and inputs it into a light receiver.

An example of such a conventional method and apparatus is schematically illustrated in FIG. 1. FIG. 1 shows a vacuum chamber of a 10ij thin film forming apparatus, and the lower part of the vacuum chamber contains vapor deposition substances and B, and is electrically heated. Evaporation sources 12a and 12b, which can be heated by vessels 11a and 11b, respectively, are arranged.Evaporation sources 12a and 12 bij are provided with shutters 13m and 13b, which can be opened and closed, respectively. Inside and above the vacuum chamber 10, there is a transfer mechanism 1 for a long substrate 14.
5 will be deployed. In the transfer mechanism 15, the substrate 14 is transferred back and forth between the two winding rolls 16 and 17 via guide rolls 19, 20, and guide rolls 21 and 22'. When the substrate 14 is transferred in one direction, that is, to the right, the evaporation source 12m is energized (the straddle shutter 15a is opened), and a thin film of the vapor deposition substance A is vapor-deposited on the surface of the substrate 14. 14 is transferred in the other direction, that is, to the left, the evaporation source 12b is energized (
Further, the shutter 13b is opened) to deposit a thin film of the deposition material B, and thus a multilayer film of the deposition materials A and B is formed by reciprocating the substrate 14.

The thin film forming apparatus described above, ie, the vacuum evaporation apparatus, has two optical monitors 22a and 22b, which are connected to the light projector 2.
3. Equipped with a semi-transparent mirror 2A and a light receiver 25. Floodlight 2
The light emitted from the substrate 1 is reflected by the translucent GP 2a, passes through the monitoring window 26f provided in the vacuum chamber 10, and then reaches the substrate 1.
The light is reflected by the thin film on 4, passes through the monitoring window 26 in the opposite direction, and then passes through the semi-transparent mirror 24 and enters the light receiver 25. The photoreceiver 25 has the above-mentioned configuration, which outputs an output signal that varies in strength depending on the intensity of the KFs light, that is, the reflected light, and thus depending on the reflectance of the thin film. Does the output signal become stronger or weaker depending on the strength of the received signal and therefore the transmittance of the thin film? The configuration may be arranged to occur.

In the illustrated example, a thin film is formed on the surface of the base body 14 in the area of the cooling rotating barrel 20, and as the base body 14 moves to the right, the thin film thus formed is monitored by the right-hand optical monitor 22b. When the base body 14 moves to the left, the optical monitor 22m on the left side of the KH is activated.

The output signals from both floodlights 25 are each amplified by an amplifier 27, and then inputted to an attached control operation panel 29 and an automatic control circuit such as a multi-input recorder or display 28 and a two-way combination system as required. do. Control operation panel 29t
C is further k, a controller 30 for controlling the rotation speed of the rotating cylinder 200, a detecting unit 31 for detecting pressure, etc., and an electric heater 11a of the evaporation source 121.12b.

11b power control section 32 and evaporation rate monitor section 3
Hereinafter, in the description of the prior art and the present invention, it will be mainly described that the reflected light of the optical monitors 22m and 22btj is monitored, and accordingly, the reflectance is monitored. Monitoring can also be done in exactly the same way.In the conventional system described above, the reflectance (transmission i*) is monitored by the optical monitor 22 to control the film thickness. The reflectance (or transmittance) R of the dielectric thin film is 1/1/ of the wavelength of the incident light in the thin film%.
It is utilized that it is a periodic function of the optical film thickness nd (the refractive index of the nH thin film, d is the actual thickness) with a period of 1/2 of this wavelength. Taking this point into consideration, the wavelength λ is such that ndo = j4/J (jzl, 2.5---) is satisfied for the optical film thickness ndo corresponding to the desired film thickness. is selected as the specific wavelength.

If K monitors the rising part where the thickness of the thin film gradually increases from 0, then when the reflectance (transmittance) R increases or decreases and takes the jth extreme value, K ( j
In the case of m 1, when KViR takes the first extreme value, K) the optical film thickness reaches a desired value of 1xd□K. After that, the film thickness is controlled so as to maintain this extreme value.

However, according to this conventional technique, the characteristics to be obtained, especially the optical characteristics, are determined only by the film thickness or optical film thickness, and the reflectance (transmittance) R of light at a specific wavelength, that is, the monitoring wavelength λ0, is determined by the above-mentioned A thin film with desired characteristics can be formed only when it has a clear extreme value, such as in the case. For this reason, the conventional technology is suitable only for forming a limited number of optical films, such as a 174-wavelength alternating multilayer film.In addition, the optical properties of general antireflection films, selective absorption films, inhomogeneous films, etc. In addition to thickness, it varies significantly depending on factors such as film composition, film composition distribution, partial pressure and flow rate of the reaction gas during reactive deposition, and evaporation rate of the deposited material, so it is important to monitor only the reflectance (transmittance) at a specific wavelength. However, it is difficult to obtain desired optical properties.

Furthermore, according to the prior art, in order to determine the spectral characteristics of the formed thin film, a destructive test such as cutting a sample from the formed long thin film is required.

Therefore, it is an object of the present invention to eliminate the above-mentioned drawbacks of the prior art. To achieve this object, according to the present invention, a substrate is transferred to an evaporation source, and a vacuum evaporation process is performed on the surface of the substrate. A method for monitoring the film thickness of a thin film based on a change in reflectance or transmittance of the thin film with respect to light of a constant wavelength when forming a thin film, wherein a number of wavelengths including or not including the specific wavelength are used. A method for monitoring and measuring a thin film in a thin film forming apparatus is provided, which is characterized in that the optical properties of the thin film can be controlled by simultaneously measuring the spectral characteristics of the thin film. As an example, light from a projector is applied to a thin film forming apparatus in which an evaporation source and a mechanism for transferring a substrate to the source are placed in a vacuum chamber so that a thin film can be formed by vacuum deposition on the surface of the substrate being transferred. It is equipped with an optical monitor that extracts light of a specific wavelength for film thickness monitoring from the light that is projected onto the thin film and transmitted through or reflected from the thin film and inputs it into one or more receivers. There is provided a thin film monitoring and measuring device for a thin film forming apparatus, characterized in that output signals from one or more of the light receivers described above can be input to both a film thickness monitoring section and a spectral characteristic measuring section. Another example is a thin film forming apparatus in which an evaporation source and a mechanism for transferring a substrate to the source are placed in a vacuum chamber so that a thin film can be formed by vacuum deposition on the surface of the substrate being transferred. Projects light onto a thin film, extracts light of a specific wavelength for film thickness monitoring from the light that is completely transmitted through the thin film, and sends it to one or many receivers.Nine optical monitors are included. in which light having a wavelength other than the constant wavelength is extracted from the transmitted or reflected light power and transmitted to another one or more receivers other than the one or more receivers. The optical monitor is configured and arranged so that the optical monitor can be input into the film thickness monitoring unit and/or the spectral characteristic measuring unit. There is provided a thin film monitoring and measuring device for a thin film forming apparatus, which is characterized in that it is capable of:

Embodiments of the present invention will be described in detail below with reference to the drawings.

According to an embodiment of the invention, an apparatus can be used which is S+ constructed and operates in the same manner as the conventional apparatus of FIG. 1 except for the optical monitor and related components.In the embodiment shown in FIG. The light emitted from the floodlight 23 of 34 is reflected by the semi-transparent fi 24, and is reflected by the monitoring window 26 provided in the vacuum chamber.
The emitted light is reflected by a thin film on the substrate 14, passes back through a monitoring window 26 (the emitted light may also be transmitted through the thin film), and is transmitted through a semi-transparent obtuse 24. Semi-transparent mirror 2At - The transmitted light is divided into three beams by semi-transparent mirrors 35m, 35b and reflecting mirror 55cK, and then passed through a narrow band filter 36m whose passing wavelengths are λa, λb and λC.
56b and 56e respectively to the receiver 25m,
There are 25b and 25cKij. Receivers 25m and 2 correspond to the intensities of the light beams of wavelengths λa, λb and λC, respectively.
The output signals from 5b and 25C are amplified by film thickness monitoring amplifiers 37m, 37b and 37e, respectively, and then sent to a multi-pen recorder or display 29 for film thickness monitoring output and an automatic control circuit if necessary. The display 29 and a part of the control panel 28 constitute a film thickness viewing section, and each wavelength λa, λby, and λcK are input into an amplifier 37m, 3
7b and 37e amplified and the time of the 9 output signal (b) (
1) Display the leopard change and also make a lamp. In this film thickness monitoring section, film thickness monitoring and control are achieved in the same manner as in the conventional method.
On the other hand, the output signal from the spectral characteristic measurement amplifier 3
After being amplified by 8a, 38b and 38c, the light is processed by a multi-pen recorder or display 39 for displaying light characteristics and the aforementioned control panel 28 by nine people.

The recorder or display 39 constitutes a spectral characteristic measuring section together with the corresponding part of the control panel 28.
and λC for amplifiers 38&, 38b and 38c
The output signal side amplified by time σ) changes on the time axis σ)
Distribute or display in a staggered manner.

Amplifier for measuring spectral characteristics! 181. The amplification factor M of 38b and 38e is set, for example, as follows: - In the case of measuring spectral transmittance, the substrate 14 may be measured without the substrate 14 or by providing a hole in a part of the substrate and exposing it to light. Amplifiers 38 for each of the wavelengths λ, λb, λC
Therefore, the amplification factor M is set so that the output of 38b and 38c becomes 100%, and the precept is that when using a substrate with known spectral transmittance, the amplifier output level for each wavelength is equal to the spectral spectral value of the substrate. When measuring spectral reflectance, the amplification factor M is set to match the transmittance.1 When using a substrate with known spectral reflectance, the amplification factor output level for each wavelength is equal to that of the substrate. The trap amplifying wheel M is set to match the spectral reflectance, and the precept is to set the S amplifying wheel M so that the signal for all wavelengths to the substrate has the same output level, for example, 1001. The measured value is converted.Furthermore, if the spectral transmittance or spectral reflectance of the substrate is unknown, an attached substrate with known spectral characteristics is connected and the amplification factor M It is also possible to set the wavelength for monitoring the film thickness and the wavelength for measuring the spectral characteristics (this is In the embodiment shown in FIG. 2 described above, the output signals match, but in the embodiment shown in FIG. By controlling the input of the evaporation source (electric heater), the transfer speed of the substrate, the pressure, etc. based on the indication, a thin film having desired optical properties can be reliably formed.

In the embodiment shown in Fig. 2, the F'i film thickness monitoring wavelength and the spectral characteristic measurement wavelength match, but this embodiment can be modified so that these two wavelengths are different, so that they partially match. It is clear that the embodiment shown in FIG. 2 allows the light of each wavelength to be successively delivered to the receiver, but the light for each wavelength is sequentially sorted or It can also be scanned. Such an embodiment is shown in FIG. In this FIG. 3, in the same manner as in the embodiment shown in FIG.
Therefore, one luminous flux uti divided into two luminous fluxes U and vK
The semi-transparent mirrors 40a, JOb, 40c and the reflecting mirror 40d divide the luminous flux into four beams a% b-cud, and the scanning plate 4
After passing through 1, the passing wavelengths are λb, λb, and λ, respectively.
C1λd narrowband filters 36g, 36b,
36c and 36d, respectively, and is focused to pass through one optical path by a reflecting mirror 42m and semitransparent mirrors KA2b, 42e, and 42d, and then the first visible light receiver 2
I'm in 5u. The luminous flux V t is a semi-transparent mirror 406.40f,
JDg>j and reflection @40 hK Therefore, four luminous fluxes e, f
, g, and hK, and after passing through the scanning plate 41, the passing wavelengths are λ. , λf, λg, λh, respectively.
After the light is focused to pass through one optical path by h, there is a second light receiver 25vtCtl for infrared light.

As shown in FIGS. 4 and 5, the scanning plate 41ij is a disc that can rotate around the axis 43 and extends along the arc of L900! Slot holes 44, 44b, 44c
, 44d%44m, 441.44g and 44h1, and these slots emit light beams 1,b, (!) from the axis of the shaft 43.
s d s ・, b equal to the distance to f, g and h
has a radius. When these slotted Fi scanning plates 41 rotate nine times as indicated by the arrows in FIG.
2nd 1/4 turn, 3rd 1/4 turn and 4th 1/4 turn
The scanning plate 41 is arranged so that only the light beams a and 1%, b and 1% C and g, and d and h pass through the scanning plate 41 in four rotations.

The arrow in FIG. 5 indicates the scanning direction. Therefore, the scanning plate 41
By rotating the receiver 25uKij wavelengths λa, λb, λ
Luminous fluxes a, b, c%d of C2λd repeatedly arrive in this order, and in synchronization with this, the wavelength λe arrives at the light receiver 25.

Luminous fluxes λf, λg, and λh arrive repeatedly in this order.

The output signal from the photoreceiver 25u is amplified by an amplifier A5u including a light source control circuit, and then is sent to a multi-pen recorder or display 4529 for film thickness monitoring output via film thickness monitoring amplifiers 37m and 37bt. The automatic control circuit can be input to the attached control panel 2B as necessary, and on the other hand, the spectral characteristic measurement amplifiers 38, 38b, 38e, 38dl-
After that, the output signal from the optical receiver 25 can be inputted to the spectral characteristic display multi-recorder or display 39 and the control operation @28, and the output signal from the photoreceiver 25 is amplified by the amplifier @543 including the light source control circuit. On the other hand, the film thickness monitoring amplifiers 37e and 37
ft-, a multi-input recorder for film thickness monitoring output display, an Fi display 29 and a control operation panel 28, and an amplifier 58, 38f%, 38g, 38h for measuring spectral characteristics.
The data can be input to the multi-pen recorder for displaying spectral characteristics or to the display 39 and the control panel 28 via the . However, such a circuit part necessarily includes a synchronous circuit that operates in synchronization with the rotation of the scanning plate 41 according to IK, for example, the light flux a and...
At the time when the output signals from amplifiers 25u and 25ma are sent, selection or scanning is performed so that only the signals that have passed through amplifiers 37& and 58m and amplifier 38e1 are displayed or written back and become the control targets.
The same applies to other luminous fluxes. amplifier 38 m,
38 b, 58 c, 38d, 38・, 38f,
The method of setting the amplification factor M for 38g and 38h is the same as in the case of FIG. In addition, each food can be easily modified in the same way as described for Example 9 in FIG. I can make it.

Examples of wavelengths for film thickness monitoring and wavelengths for measuring spectral characteristics that can be employed in the method and apparatus of the present invention are shown in Table (
This is the general rule of II. This invention is configured as described above.

Kei Kinzoku GT9 is able to achieve control of one film thickness for the collection film so that the reflective screen (transmission film) for light of a specific line length does not show a clear extreme value with respect to film thickness. General anti-reflection coating whose optical properties change depending on the situation, selection 1
1J [11, selectively permeable films, inhomogeneous films, etc. can be formed to have desired optical properties, and the optical properties of long optical thin films can be tested non-destructively and continuously. can be achieved at the same time. & which has many advantages

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one example of a conventional thin film forming apparatus, and FIG. 2 is a first embodiment of the apparatus of the present invention, showing only points IIE and 311F that are different from those in FIG. 1. ! 2nd Ill as well as fkE for the second embodiment of the device of the invention, 4th
The figure is a front view of the scanning plate used in the device of SWJ No. 5.
The figure is a side view of the scanning plate shown in FIG. 4. In the drawing, 10 vacuum chambers, 12 m and 12 b are evaporation sources, 14 is a substrate, 16 to 21 and 22' are mechanisms for transferring the substrate, and 23 is a projector. 25a125b, 250
% 25u and 25vij receivers, 29 is the film thickness monitoring section, and 39 is the spectral characteristic measurement section.

Claims (1)

[Claims] 1. Based on changes in the reflectance or transmittance of the thin film for light of a specific wavelength when the substrate is transferred to an evaporation source and a thin film is formed by vacuum deposition on the surface of a black body. In the method of monitoring the film thickness of a thin film using
A method for monitoring and measuring thin films in a thin film forming apparatus, characterized in that: 2. A thin film forming apparatus K in which an evaporation source and a mechanism for transferring the substrate to the evaporation source are arranged in a vacuum chamber so that a thin film can be formed by vacuum deposition on the surface of the substrate being transferred; Light of a specific wavelength for film thickness monitoring is extracted from the light that is projected onto the screen and transmitted through or is rejected by the light, and the light of a specific wavelength is sent to one or many receivers, and is equipped with nine optical monitors. 8. Evaporation thin film monitoring and measuring device in a thin film forming apparatus, characterized in that one or more of the above is capable of inputting output signals from many light receivers to both a film thickness monitoring section and a spectral characteristic measuring section. A light source and a mechanism for transferring the substrate to the thin film forming apparatus are arranged in a vacuum chamber so that a thin film can be formed by vacuum deposition on the surface of the substrate being transferred, and light is projected onto the thin film from a projector. In a device that is attached with an optical monitoring device that extracts light of a specific wavelength for film thickness monitoring from the light transmitted through the lamp and reflected by the lamp and enters it into one or many light receivers, the above-mentioned Or, nine optical monitors are configured and arranged so that light having a wavelength other than the specific wavelength can be extracted from the reflected light and input into one or more receivers other than the one or more receivers. The thin film is characterized in that an output signal from a light receiver of a specific wavelength and an output signal from another light receiver can be input to a film thickness monitoring section and/or a spectral characteristic measuring section. Thin film monitoring and measuring device in forming equipment.