JP2001123265A - Manufacturing method of molding, and film depositing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deposit a film without irregular film thickness on a work having a curvature. SOLUTION: A film depositing method of a molding is a molding manufacturing method having a film depositing process to form the film on the work by a vacuum vapor deposition method, and a film depositing particle shielding plate number controlling process to set the installation number of the film depositing particle shielding plates so as not to substantially generate any irregular film thickness of the film to be deposited is provided in installing the film depositing particle shielding plates having one kind of shape between a vapor deposition source in a film depositing apparatus and the work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a molded article having a film having a small thickness variation and a film forming apparatus.

[0002]

2. Description of the Related Art A conventional film forming apparatus is provided with a plurality of film-forming particle shielding plates (hereinafter referred to as "shielding plates") in order to prevent film thickness unevenness. By providing this shielding plate, the amount of vapor deposition particles reaching the base material can be controlled, and as a result, the thickness of the film to be formed can be prevented from being uneven.

Conventionally, a fixed number of shielding plates having the same shape are provided regardless of film forming conditions. And the shape of the shielding plate assumes that a film is formed on a planar film-forming object,
It has been determined that film thickness unevenness does not occur in the film formed on the plane. The conventional film forming apparatus has such a shielding plate.

[0004]

The inventor of the present invention has formed an anti-reflection film on a film-forming object having a curvature, such as a lens substrate, by using a film forming apparatus conventionally used as described above. Tried to film. Then, when the lens on which the antireflection film was formed was incorporated into an optical device, there was a problem that the performance of the optical system deteriorated.

[0005]

SUMMARY OF THE INVENTION The present inventor has searched for the cause of performance degradation of an optical system. As a result, it was found that the cause was insufficient light quantity at the periphery of the lens. Further, when the cause of the light quantity shortage was studied, it was found that the cause was that the thickness of the antireflection film formed on the peripheral portion of the lens was thinner than other portions. That is, it was found that the above-mentioned problem occurs because the formed anti-reflection film has uneven film thickness when viewed from the whole lens. When the film thickness unevenness occurs, the performance of the film differs depending on the location in the plane of the formed film.

Further, the present inventor has searched for the cause of the occurrence of uneven film thickness. As a result, it was found that there was a problem in the condition of the shielding plate initially set at the time of film formation. As described above, conventionally, the shape and the number of shielding plates initially set at the time of film formation are set on the assumption that the object to be film-formed is planar. Therefore, it has been found that in the case where the object to be formed has a curvature, the condition set on the assumption that the object is a planar object may not be met in some cases. In particular, a multilayer film is a material in which the materials of the films constituting each layer are different. Therefore, the condition of the shielding plate differs between different substances. However, it has been found that, in the related art, since the film is not formed by changing the condition of the shielding plate for each layer, the film thickness becomes uneven for each film. Even if the problem can be solved by replacing the shielding plate for each layer and forming a multilayer film, this method is very troublesome and is not a practical solution.

SUMMARY OF THE INVENTION It is an object of the present invention to efficiently form a film having a small thickness on a film-forming object having a curvature.
Therefore, the present invention firstly provides a method for manufacturing a molded article having a film forming step of forming a film on a film formation object by a vacuum evaporation method, wherein the method comprises the steps of: In installing a film-forming particle shielding plate having one type of shape, the number of the film-forming particle shielding plates is set to the number of films to be formed so that the film thickness unevenness of the film to be formed does not substantially occur. A method for controlling the number of the film-formed particle shielding plates to be formed (claim 1). " Secondly, the manufacturing process of the molded product according to claim 1, wherein "the step of controlling the number of the film-forming particle shielding plates is performed based on information on the shape of the film-forming object and / or the film-forming substance. A method (Claim 2) is provided. Third, the shape of the film-formed particle shielding plate is determined by the following equation.
Or the manufacturing method of the molded object of 2. Equation 1

[0008]

(Equation 2)

In the formula, L is the width of the shielding plate (the length in the Y-axis direction in FIG. 3), r is the distance from the center of revolution to the correction position, n is the number of shielding plates, and l is the axis of the mounting axis of the shielding plate. The width, d is the film thickness of the film formed at the correction position, r0 is the distance from the center of revolution to the center of the object, and d0 is the film thickness at the center of the lens. Fourthly, a “vacuum chamber, an installation section for an evaporation source installed in the vacuum chamber, a deposition object holding section for installing a deposition object at a position facing the installation section, A film deposition apparatus having a film-forming particle shielding plate between the film-forming particle shielding plate and the holding unit, wherein the number of the film-forming particle shielding plates installed is set based on a condition under which film thickness unevenness does not occur. A film forming apparatus characterized by the above-mentioned (claim 4) "is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The film thickness unevenness of a film formed by a vapor deposition method depends on the distance between the vapor-deposited particles and a film-formed object, the incident angle of the vapor-deposited particles on the film-formed object, or the thickness of the vapor-deposited particles in a chamber. This is caused by the distribution state or the like. As described in the description of the related art, the film thickness unevenness can be reduced by controlling the amount of vapor deposition particles by installing a shielding plate between the vapor deposition source and the object.

As a method of using a shielding plate, there is a method of controlling by changing the shape of the shielding plate. But with this method,
The shield plate must be changed each time the shape of the object to be formed changes or the material to be formed changes. In the present invention, film thickness unevenness is reduced by using shielding plates having the same shape and controlling the number of shielding plates and their installation positions. Accordingly, a film with small thickness unevenness can be formed without changing the shape of the shielding plate every time the film forming conditions change and regardless of the shape of the object to be formed.

[0012] The shape of the shielding plate used in the present invention is set to a shape that does not cause unevenness in film thickness when a film-forming object having the largest film thickness unevenness or a film-forming substance having the largest film thickness unevenness is used. . FIG. 1 is a conceptual diagram illustrating a film forming apparatus (vacuum vapor deposition apparatus) used in this embodiment. In this embodiment, the object to be formed has a diameter of 200 mm and a radius of curvature of 200 mm.
mm, 300 mm, having a curved surface of 400 mm,
A planar object to be formed having the same diameter was used. And
Film formation is performed on these objects.

As shown in FIG. 1, an object to be film-formed (a lens in the figure) is separated from the evaporation source by a distance b in the vertical direction.
It is installed around a revolution axis that rotates around the evaporation source. Further, the film-forming object has a distance c perpendicular to the revolution axis.
(Distance to the center of the object). The object to be film-formed rotates at this position during film-forming. The revolving speed is
Set to 6 revolutions / minute, and the ratio between revolution and rotation is 1 revolution.
The number of rotations was set to 2.52 times.

As shown in FIG. 1, the shielding plate is provided between the object to be formed and the evaporation source. Specifically, the shielding plate is spaced apart from the evaporation source by a distance a in the vertical direction, and is installed around a revolution axis that rotates about the evaporation source. Further, the shielding plate is installed at a position at a distance d (distance to one end of the shielding plate) in a direction perpendicular to the revolution axis. In the present embodiment, a = 945
mm, b = 995 mm, c = 335 mm, d = 210 m
m, and a film-forming object and a shielding plate were provided.

FIG. 2 shows a conceptual view of the vacuum deposition apparatus as viewed from above. In the present embodiment, the number of shield plates is ten (only nine are shown in FIG. 2), and each is installed on a shield plate mounting shaft (width: about 5 mm) arranged at equal intervals. Magnesium fluoride was used as a deposition material, and a deposition target was heated to 250 ° C. during deposition to form a film.

The method of determining the shape of the shielding slope is basically the same as the method of determining the shape of the shielding plate for preventing the film thickness unevenness of the film formed on the planar object to be formed. However, in the case of the present invention, in consideration of the fact that a film is formed on a film-formed object having a curved surface, unevenness of the film thickness on a plane formed on a planar film-formed object is reduced. The difference is that thickness unevenness (thickness unevenness on a film formation surface on a film formation object having a finite value of curvature) is replaced.

First, a film-forming object which is known from experience to have uneven film thickness is set in a film forming apparatus, and a film is formed on the film-forming object without a shielding plate. I do. At this time, the object is rotated and revolved. Then, after the film formation, the film thickness unevenness in the surface of the film formation object is examined. The film thickness unevenness is obtained by measuring the spectral characteristics of the film and converting the peak from the measurement result to obtain data. Since the obtained data on the film thickness unevenness is data on a film formed by rotating the film-forming object, the film thickness unevenness is formed symmetrically with respect to the center of the film-forming object. Therefore, the film thickness unevenness changes in accordance with the distance from the center of the film formation object. Therefore, the film thickness unevenness may be determined only in the radial direction from the center of the object.

The obtained data is substituted into the following equation 1 to determine the shape of the shielding plate. Equation 1

[0019]

(Equation 3)

In the formula, L is the width of the shielding plate (the length in the Y-axis direction in FIG. 3), r is the distance from the center of revolution to the correction position, n is the number of shielding plates, and l is the axis of the mounting axis of the shielding plate. The width, d is the film thickness of the film formed at the correction position, r0 is the distance from the center of revolution to the center of the object, and d0 is the film thickness at the lens center.

The shielding plate whose outline is determined by the above equation is actually attached to the film forming apparatus. Then, vapor deposition is repeated while changing the dimensions little by little, and a shielding plate having a shape with no unevenness in film thickness is determined. In this embodiment mode, the in-plane film thickness unevenness is 0.3% with respect to the center film thickness of the film formation object.
Within.

Table 1 shows numerical data of the shape of the shielding plate thus obtained.

[0023]

[Table 1]

X and y in Table 1 indicate the x and y directions in FIG. 3, and each numerical value indicates its size. Table 1
The position of middle x = 0 is a position of a distance (mm) of d from the revolution axis in FIG. Next, the number of shielding plates is determined. The number is determined as follows. First,
Ten shield plates of the shape determined as described above are installed and vapor deposition is performed. After that, vapor deposition is performed while reducing the number of shielding slopes. This operation is performed for each film-forming object having each radius of curvature. Then, the film thickness unevenness in the surface of the film formation object is examined, and the number of shielding plates having a sufficiently small film thickness unevenness is determined.

The optimum number of shielding plates obtained for each film-forming object having each radius of curvature and the in-plane film thickness unevenness of the film formed under these conditions are shown. It is shown in FIG.

[0026]

[Table 2]

Referring to Table 2, when a film is formed on a lens having a radius of curvature of 200 mm by using 10 shielding plates having an optimized shape, the film thickness unevenness may be 0.3%. I understand. Also, it can be seen that even when a lens having a radius of curvature of 300 mm, 400 mm, and infinity is used, a film with less unevenness in film thickness can be obtained by forming a film while controlling the number of shielding plates.

Next, a lens having a diameter of 200 mm and a radius of curvature of 200 mm was used as a film-forming object, and magnesium fluoride and aluminum oxide were formed on the lens. The film forming conditions at this time were the same as those for forming only the magnesium fluoride, and the same shape of the shielding plate was used. Table 3 shows the results of examining the relationship between the number of shielding plates and the film thickness unevenness under these conditions.

[0029]

[Table 3]

Referring to Table 3, when a single layer film made of magnesium fluoride is formed, when the number of the shielding plates is set to 10 and the film is formed, the film thickness unevenness is 0.3%, which is a good value. Is shown. The number of shielding plates (10
In this case, when the film is formed using aluminum oxide, the film thickness unevenness becomes 6.0%, and the film thickness unevenness becomes large.

On the other hand, when the film is formed by using the number of shielding plates set by the present invention (eight), the film thickness unevenness is greatly improved as compared with the case where ten shielding plates are used. I understand.

[0032]

According to the present invention, it is possible to easily form a film having a small thickness unevenness on a film to be formed having different curvatures by using one type of shielding plate. Further, since it is not necessary to replace the shielding plate with a different shape during the film forming process, the film can be formed in a shorter time. Furthermore, since it is not necessary to prepare a plurality of types of shielding plates having different shapes, there is also an effect of reducing costs.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a film forming apparatus (vacuum vapor deposition apparatus) according to the present invention.

FIG. 2 is a conceptual diagram of a film forming apparatus (vacuum vapor deposition apparatus) according to the present invention as viewed from above.

FIG. 3 is a conceptual diagram showing a method of attaching a shielding plate according to the present invention.

Claims (4)

[Claims] 1. A method for manufacturing a molded body having a film forming step of forming a film on a film formation object by a vacuum evaporation method, wherein one type is provided between an evaporation source and a film formation object in a film formation apparatus. In setting the film-forming particle shielding plate having the shape described above, the number of the film-forming particle shielding plates to be installed is set to the number of films to be formed so that the film thickness of the film to be formed does not substantially occur. A method for producing a molded article, comprising a step of controlling the number of membrane particle shielding plates. 2. The step of controlling the number of film-formed particle shielding plates,
The method according to claim 1, wherein the method is performed based on information on a shape of the object to be film-formed and / or a film-forming substance. 3. The method according to claim 1, wherein the shape of the film-forming particle shielding plate is determined by the following equation. Equation 1 In the formula, L is the width of the shielding plate (the length in the Y-axis direction in FIG. 3), r is the distance from the center of revolution to the correction position, n is the number of shielding plates,
l is the width of the mounting axis of the shield plate, d is the film thickness of the film formed at the correction position, r0 is the distance from the center of revolution to the center of the object, and d0 is the film thickness at the center of the lens. 4. A vacuum chamber, an installation section for an evaporation source installed in the vacuum chamber, a deposition object holding section for installing an object on a position facing the installation section, and the installation section. A film forming apparatus having a film-forming particle shielding plate between a unit and the holding unit, wherein the number of the installed film-forming particle shielding plates is set based on a condition under which film thickness unevenness does not occur. A film forming apparatus, comprising: