JPH07138741A - Vacuum vapor deposition device - Google Patents

Abstract

PURPOSE:To prevent the incidence of an electron beam of an electron gun on a substrate. CONSTITUTION:A substrate W is held in the upper part of a vacuum chamber 1 and a shielding plate 5 having an opening 5a is disposed between this substrate and an evaporating source 2 disposed in the bottom of this vacuum chamber 1. This evaporating source 2 is heated by the electron gun 2b and a shutter 4 shuts off the passage of evaporated particles before the material to be evaporated in a crucible 2a is completely melted. The shutter 4 and the shielding plate 5 are respectively connected to contacts 6a, 7a of a voltage power source or grounded contact 6b, 7b and the electron beam reflected by the evaporating source 2 is effectively captured so that the incidence thereof on the substrate is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum vapor deposition apparatus for forming a thin film for laser light or the like.

[0002]

2. Description of the Related Art A vacuum vapor deposition apparatus for depositing an optical thin film such as an antireflection film on an optical component such as a lens generally has an evaporation source in a vacuum chamber, which is heated and evaporated by electron gun heating or resistance heating. The vaporized particles thus generated are deposited on the substrate. Among them, the electron gun heating type vacuum vapor deposition apparatus that evaporates the evaporation source by electron gun heating is extremely widely used because there are few restrictions on the types of substances that are vapor deposition materials, and in particular, high melting point oxides are vapor deposited. It is most often used as a material.

An electron gun heating type vacuum vapor deposition apparatus generally irradiates an evaporation material contained in a conductive crucible or a hearth with an electron beam generated from a filament of an electron gun to heat and evaporate the material. The crucible or hearth is grounded and the filament of the electron gun is made of tungsten 6-10
Applied to a negative potential of kV. The electron gun is arranged below the evaporation material contained in the crucible or the hearth, and the electron beam is bent upward by the deflection magnetic field to reach the evaporation material. This is to prevent the filament of the electron gun from being contaminated by the vaporized particles generated from the vaporized material.

[0004]

However, according to the above conventional technique, when the evaporation material is in a semi-molten state before being completely melted or partially solid, a part of the electron beam is on the surface of the evaporation material. The light is reflected and enters the substrate to generate surface defects. Such surface defects of the substrate are less likely to be a problem in the case of optical components generally used in the visible region, but optical components for high-power laser light and ultraviolet laser light, and fluorine such as fluorite. In the case of a compound substrate, there is a possibility of causing a major obstacle such as generation of a color center or deterioration of laser resistance due to unpaired electrons.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a vacuum vapor deposition apparatus in which the electron beam of an electron gun does not enter the substrate. is there.

[0006]

In order to achieve the above object, a vacuum vapor deposition apparatus of the present invention includes a vacuum chamber for holding a substrate at a predetermined portion, an evaporation source arranged in the vacuum chamber, and an evaporation source for the vacuum chamber. Electron gun heating means for heating; shielding means for shielding the predetermined portion of the vacuum chamber from the evaporation source, except for a passage of evaporation particles generated from the evaporation source toward the substrate;
It is characterized by having a shutter means capable of blocking the passage of the vaporized particles.

At least one of the shielding means and the shutter means may be grounded or positively charged.

[0008]

According to the above apparatus, when the evaporation source is heated by the electron gun heating means to generate the evaporation particles, the shutter means is closed until the evaporation source reaches a sufficiently molten state, and the evaporation source surface is kept. The reflected electron beams and the like are blocked by the shutter means and the shielding means, and these electron beams are prevented from entering the substrate and causing surface defects. If at least one of the shielding means and the shutter means is grounded or positively charged, the electron beam or the like reflected from the evaporation source can be blocked more effectively by being captured by electrostatic force.

[0009]

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

FIG. 1 is a schematic sectional view showing an embodiment, which is a vacuum chamber 1 evacuated by a vacuum pump connected to an exhaust port (not shown) and an evaporation source 2 arranged at the bottom thereof. And a dome-shaped substrate holder 3 which is detachably provided above the evaporation source 2. The evaporation source 2 is a crucible 2a opening upward and an electron gun heating means arranged below the crucible 2a. The electron gun 2 has a gun 2b, and a predetermined evaporation material of a laser optical thin film is housed in the crucible 2a.
The electron beam emitted from b reaches the evaporation material in the crucible 2a bent upward by the deflection magnetic field of a magnetic device (not shown) and heats and melts it. Also, the substrate holder 3
Holds a plurality of fluoride-made substrates W and bends them into a spherical shape centered on the crucible 2a so that the vaporized particles generated from the vaporization source 2 reach each substrate W at a uniform distance. In addition, it is rotated by a rotating device (not shown). The electron gun 2b has a tungsten filament and is applied to a negative potential of 6 to 10 kV.

Between the evaporation source 2 and the substrate holder 3, a shutter 4 which is a shutter means for blocking the flow of evaporated particles generated from the evaporation source 2 and a predetermined chamber for accommodating the substrate holder 3 in the vacuum chamber 1 are provided. A shielding plate 5 as a shielding means that divides the shutter 4 and the evaporation source 2 into two parts is provided in the upper part which is the part of the shutter 4 and the lower part which houses the evaporation source 2.
Of the evaporation source 2 can be retracted to a position where the flow of evaporation particles of the evaporation source 2 is not blocked, and the shielding plate 5 is provided on the side wall 1 of the vacuum chamber 1.
It is detachably supported on the support 1b which is integral with a through an insulating material 1c. At the center of the shielding plate 5, there is provided an opening 5a which is a passage for allowing the flow of vaporized particles generated from the vaporization source 2 when the shutter 4 retracts to reach each substrate W on the substrate holder 3. .

The shutter 4 and the shielding plate 5 are each made of a conductive material, and by switching the selector switches 6 and 7, for example, contacts 6a and 7a which are circuit means applied to a positive potential of 10 kV or ground. It is selectively connected to the contacts 6b and 7b which are the circuit means.

Vacuum deposition on each substrate W is performed as follows.

First, the electron gun 2 with the shutter 4 closed.
The melting of the evaporation material in the crucible 2a, which causes the electron beam to be generated from b, starts. While the evaporation material in the crucible 2a is in a solid or semi-molten state, a part of the electron beam of the electron gun 2b is reflected by the surface of the evaporation material in the crucible 2a and diverges upward. Further, since the shielding plate 5 is provided, and these are charged to the ground or positive potential, all the electron beams diverging upward are captured by the shutter 4 or the shielding plate 5, and the upper space of the vacuum chamber 1 is There is no danger of reaching. Therefore, unlike the conventional case, there is no possibility that the electron beam reflected from the evaporation source 2 enters each substrate W and causes a surface defect.

When the evaporation material in the crucible 2a is sufficiently melted, the shutter 4 is retracted and the evaporation particles irradiated onto the upper space of the vacuum chamber 1 through the opening 5a of the shielding plate 5 are adhered to each substrate W. By thus forming the optical thin film for the laser, it is possible to prevent the generation of the color center due to the surface defect of the substrate and the reduction of the laser resistance due to the unpaired electrons.

The size of the opening 5a of the shielding plate 5 is as shown in FIG.
As shown in FIG. 5, it is preferable that the distance L between the crucible 2a and the substrate holder 3 and the distance h between the crucible 2a and the shield plate 5 have the following relationship.

H / φ = L / R (1) where φ: diameter of the opening 5a R: diameter of the substrate holder so that the size of the opening 5a of the shielding plate 5 satisfies the equation (1). If set to, the evaporation particles generated from the evaporation source 2 can reach the surface of each substrate W without wasting. It should be noted that the shutter 4 and the shielding plate 5 are changed from the grounded state to the state in which a positive potential is applied by switching the respective changeover switches 6 and 7, and further, the voltage thereof is set to 10 kV.
When the presence or absence of a color center and the laser proof strength of the optical thin film formed by changing the temperature were examined, no difference due to the voltage of the shutter 4 or the shielding plate 5 was found.

In this embodiment, the shutter and the shielding plate are individually connected to the ground or a positive voltage power source, but they are connected to a single changeover switch and connected to a common ground electrode or a positive electrode. It goes without saying that you can also connect. Further, if the reflected electron beam is small, only one of the shutter and the shielding plate may be grounded or charged to a positive potential.

According to the present embodiment, the electron beam reflected on the surface of the evaporation source is blocked by the shutter and the shield plate, and at least one of the shutter and the shield plate is grounded or positively charged to cause the electrons to be emitted. Since the beam can be effectively captured, there is no possibility that the electron beam will be incident on the substrate and cause surface defects.

[0020]

Since the present invention is constructed as described above, it has the following effects.

In an electron gun heating type vacuum vapor deposition apparatus,
There is no risk that an electron beam or the like reflected on the surface of the evaporation source will enter the substrate before the evaporation source reaches a sufficiently molten state to generate surface defects. As a result, it is possible to obtain an optical thin film which is extremely good in quality and has excellent laser resistance particularly when a substrate is made of an optical component for high-power laser light or ultraviolet laser light or a fluoride such as fluorite.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a vacuum vapor deposition device according to an embodiment.

FIG. 2 is a diagram for explaining the size of an opening of a shielding plate of the device shown in FIG.

[Explanation of symbols]

 W substrate 1 vacuum chamber 1a side wall 1b support 1c insulating material 2 evaporation source 2a crucible 2b electron gun 3 substrate holder 4 shutter 4a rotating shaft 5 shield plate 5a opening 6,7 changeover switch 6a, 6b, 7a, 7b contact

Claims (5)

[Claims] 1. A vacuum chamber for holding a substrate at a predetermined site,
The evaporation source provided in the vacuum chamber, an electron gun heating means for heating the evaporation source, and a passage for vaporized particles generated from the evaporation source toward the substrate are removed from the predetermined portion of the vacuum chamber. A vacuum vapor deposition apparatus comprising: a shielding means for shielding from the evaporation source and a shutter means capable of shielding the passage of the evaporated particles. 2. The vacuum vapor deposition apparatus according to claim 1, wherein at least one of the shielding means and the shutter means is grounded or positively charged. 3. The vacuum vapor deposition apparatus according to claim 1, wherein both the shielding means and the shutter means are grounded or positively charged by separate circuit means. 4. The vacuum vapor deposition apparatus according to claim 1, wherein both the shielding means and the shutter means are grounded or positively charged by a common circuit means. 5. The vacuum vapor deposition apparatus according to claim 1, wherein the shielding means is a detachable shielding plate.