JPS6034046B2 - Thin film generation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes changes in the reflectance of the optical fiber end face due to a thin film formed and adhered to the end face of an optical fiber in a belljar for thin film production, which depends on the thickness of the optical fiber end face, to the amount of light reflected from the other end face of the other fiber outside the belljar. This invention relates to a thin film production device that is equipped with a film thickness monitoring function that monitors the thickness of the thin film produced on the substrate surface in the bell jar.

As shown in Figure 1, when a material with a refractive index of n and a thickness of d is attached to a material with a refractive index of is given by for the light of .

Ratio=1. Figure 2 shows Rd when Fn = 2.5 and ^ = 8000A. Reflectance changes periodically with film thickness,
Changes in film thickness d can be monitored from changes in reflectance. R
Since d also has a dependence on wavelength input, when this film is irradiated with white light, the reflectance becomes strong for a specific wavelength, and so-called "interference color" is observed. Attempts have been made to use this method to monitor film thickness from the outside. However, it had the disadvantage of poor accuracy because it was monitored through a bell jar or glass used in windows. The present invention utilizes the fact that a film with a refractive index different from that of the optical fiber is formed on one end face of the optical fiber, thereby changing the reflectance of the end face when viewed from the fiber side, and couples this optical measurement system to a thin film generation device. The object of the present invention is to provide a new and useful thin film production device that can monitor the thickness of the produced thin film.

Another object of the present invention is that since the optical fiber itself acts as a light transmission path, the optical fiber can be inserted into any device without a window for extracting light, as long as the optical fiber does not deteriorate. The object of the present invention is to establish a film thickness monitoring device that can monitor film thickness. Furthermore, since optical fibers have low loss and are not affected by external influences, extremely accurate measurements can be made compared to cases where light is extracted through a window or the like. Hereinafter, the present invention will be explained in detail according to examples and with drawings.

FIG. 3 shows one embodiment of the present invention, and is an explanatory diagram of the structure when the present invention is applied directly to a normal vacuum evaporation system. A vapor deposition source 2 and a thin film forming substrate 3 are placed in a bell jar, and an optical fiber 4 is inserted from the side wall. One end of the optical fiber 4 is placed close to the substrate 3, and the end face faces the vapor deposition source 2.
As a means of monitoring the film thickness of the thin film formed on the substrate 3 by using the optical fiber 4, the light from the laser light source 7 is made to enter the optical fiber 4 using the coupling lens 5, and the optical fiber 4 is placed at the same level as the substrate 3. The light reflected from one end of the optical fiber coated with a thin film is input into a detector 8 using a semi-transparent mirror 6, and the output of the detector 8 is monitored. The thickness of the thin film produced can be monitored. The part surrounded by the broken line in FIG. 3 shows a measurement system using optical detection. Regarding the measurement system, if a semiconductor laser 9 is used as the light source as in the other embodiment shown in FIG. 4, the reflected light intensity can be monitored more easily than with a fiber due to the self-coupling effect unique to semiconductor lasers, and the measurement system can be improved. It can be made simple. When considering the self-coupling effect as a change in the optical output of the semiconductor laser, the detector 8 in Fig.
However, if the change is detected as a change in the terminal voltage of the semiconductor laser, the detector 8 is not necessary. When using a semiconductor laser, it is better to have less reflection of light from the input end face when entering the fiber light, and it is desirable to apply an antireflection film such as a conductive multilayer film to the input end face of the fiber.
According to the present invention, the amount of reflected feedback light from a thin film having a film thickness equivalent to that of the thin film on the substrate, which is generated on the inner end face of the bell jar of the optical fiber, is taken out by optical fiber transmission and detected, thereby generating the light on the substrate. The thickness of the thin film can be determined. That is, the present invention does not directly irradiate a thin film formed on a substrate, but instead forms a thin film having a thickness equivalent to that of the thin film formed on the substrate on the end face of optical fibers arranged in parallel with the substrate. By using this thin film, the thickness of the thin film on the substrate can be determined, and it is possible to monitor in real time the progress of thin film formation, which gradually thickens during the process of forming a thin film on the substrate. .

[Brief explanation of the drawing]

Figure 1 shows a material with a refractive index of ~, a material with a refractive index of n, and a thickness of d.
FIG. 3 is an explanatory diagram illustrating the reflection of light when the particles are attached. Figure 2 is an example of calculating the reflectance (=reflected light/incident light) in Figure 1, and when ~=1.5 and n.=2.5, the wavelength is 8.
It is an explanatory view showing the result of calculating the value for 000A. FIG. 3 is a structural explanatory diagram showing one embodiment in which the present invention is applied to a vacuum evaporation layer. FIG. 4 is an explanatory diagram showing an embodiment in which the measurement system enclosed by the dotted line in FIG. 3 is constituted by a semiconductor laser. 1... Bellja, 2...
... Dust source, 3 ... Substrate, 4 ... Optical fiber, 5 ... Coupling lens, 6 ... Semi-transparent mirror,
7... Laser light source, 8... Detector, 9
・・・・・・Semiconductor laser. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a thin film production device for producing a raw material as a thin film on a substrate surface, an optical fiber is arranged in parallel on the substrate with one end face facing the raw material source, and an output light source is provided on the other end face of the optical fiber. Optically coupled to a detector that detects the reflected feedback light of the light output from the output source, a thin film having an equivalent film thickness is produced in response to changes in the thickness of the thin films sequentially produced on the substrate. On one end surface of the optical fiber, the output light output from the output light source into the optical fiber is irradiated onto the thin film, and the amount of reflected light of the output light that changes according to a change in the thickness of the thin film is measured. A thin film production device comprising a film thickness monitoring function for determining the thickness of a thin film produced on the substrate by detecting it with the detector.