JP2000178728A - Device for producing optical thin film and production of optical thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for producing an optical thin film capable of widening the range of the refractive index of the optical thin film to all ranges decided by the materials of sputtering targets. SOLUTION: In a device for producing an optical thin film forming the optical thin film on a film forming substrate 17 by a magnetron sputtering method, the device has a 1st magnetron sputtering electrode 4 to be disposed with a sputtering target 6, a 2nd magnetron sputtering electrode 5 to be disposed with a sputtering target 7 different from the sputtering target 6, a shuttering mechanism 21 provided on the space between the film forming substrate 17 and the 1st magnetron sputtering electrode 5 and controlling the amt. of the sputtering particles to be arrived at the film forming substrate 17 caused by the sputtering target 6 and a shuttering mechanism 22 provided on the space between the film forming substrate 17 and the 2nd magnetron sputtering electrode 7 and controlling the amt. of the sputtering particles to be arrived at the film forming substrate 17 caused by the sputtering target 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical thin film manufacturing apparatus for forming an optical thin film having an arbitrary refractive index, and a method for manufacturing an optical thin film having an arbitrary refractive index.

[0002]

2. Description of the Related Art In general, thin films are used in a wide range of fields such as the optical field and the electronics field, and many functions which can be realized only by these thin films are realized.

[0003] There are various methods for producing such a thin film, and among them, a sputtering method is one of the frequently used methods. The sputtering method has an advantage that it is easy to control the composition and the formation rate of the thin film.

[0004] Among the sputtering methods, the magnetron sputtering method in which electrons are confined by applying a magnetic field on an electrode can increase the thin film formation speed, and is therefore established as a general high-speed film formation method at present. I have.

[0005] Further, in reactive magnetron sputtering using a metal or semiconductor as a sputtering target material, it is possible to form a film at a higher speed, and in recent years, it has been variously applied.

In the field of optical thin films, which is one of the uses of thin films, optical thin films having various optical characteristics are realized by forming a multilayer film using substances having different refractive indexes. .

However, the thin film materials that can be used for the optical thin film are limited only by the limitations of light transmission and environmental resistance, and the refractive index of the thin film is inherent to the thin film material. Actually, the degree of freedom in selecting the refractive index in the design is small.

For this reason, there is a demand for expanding the range of selection of the refractive index and increasing the degree of freedom in designing the optical thin film.

A method for forming a thin film utilizing a reactive magnetron sputtering method which meets this demand is disclosed in Japanese Patent Laid-Open No. 9-26.
No. 3937.

In this thin film forming method, a material having a high refractive index when oxidized (Ta: refractive index = 2.18) and a material having a low refractive index when oxidized (Si: refractive index = 1.4)
6) is used as a sputtering target material, and a plasma gun for reacting (oxidizing) the film to obtain a transparent thin film is used.
By controlling the ratio of the sputtering power applied to each sputtering target, a thin film having a desired refractive index (1.46 to 2.18) can be obtained at a high deposition rate within a range defined by the material to be used. .

Japanese Patent Application Laid-Open No. Hei 7-11436 describes a method of adjusting the amount of a shutter reaching a deposition substrate from each sputtering target per unit time by using a shutter.

Here, an ion beam sputtering method having a low film-forming speed is adopted, and means for opening and closing the shutter frequently and promptly is used, so that a stable mixed film can be formed.

[0013]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No. Hei 9-2
In the method described in JP-A-63937, when the ratio of the sputtering power is 0 or a value close to infinity,
If the sputtering power applied to one of the targets is small, it is difficult to maintain a stable film formation, and the refractive index range that can be obtained arbitrarily is the range defined by the material (in the above example, 1. 46 to 2.18), but not all, there is a limit on the refractive index range that can be achieved.

If power is not supplied to the sputter electrode at a predetermined value or more, it is difficult to maintain the generated plasma stably and continuously, and when the film is formed under such a condition, the optical characteristics are stable. However, there is also a problem that reproducibility is not good.

On the other hand, when the means described in Japanese Patent Application Laid-Open No. Hei 7-11436 is applied to the magnetron sputtering with a high film forming speed, the shutter frequently opens and closes quickly. Get and
In order to continuously change the mixing ratio, it is necessary to perform the opening / closing operation at a speed of about once / second or more while controlling the opening / closing time ratio of the shutter, so that a stable operation cannot be expected. There is also.

The present invention solves the above-mentioned problem, and can extend the range of the refractive index of the optical thin film that can be obtained arbitrarily to the entire range determined by the material of the sputtering target and can be configured at low cost. It is an object of the present invention to provide a thin film manufacturing apparatus and a manufacturing method capable of obtaining an optical thin film covering an entire range in which a refractive index range of an optical thin film that can be obtained arbitrarily is determined by a material of a sputtering target.

[0017]

According to the first aspect of the present invention,
In an optical thin film manufacturing apparatus for forming an optical thin film on a substrate by magnetron sputtering, a first electrode for disposing a first target and a second target different from the first target are used. 2nd to arrange
And a first shutter that is provided between the substrate and the first electrode and that adjusts the amount of sputtered particles caused by the first target to reach the substrate. A second shutter provided between the first electrode and the second electrode, the second shutter adjusting the amount of sputter particles caused by the second target to reach the substrate.

According to the present invention, when the optical thin film is formed on the substrate by the magnetron sputtering method, the first and second shutters determine the amount of sputtered particles caused by the first target to reach the substrate. Along with the adjustment, the range of the refractive index of the optical thin film formed on the substrate is reduced by a simple means of adjusting the amount of the sputtered particles caused by the second target to reach the substrate by the second shutter. It is possible to provide an optical thin film manufacturing apparatus that can be expanded to the entire range determined by the materials of the first and second targets, has a high degree of freedom in designing the refractive index of the optical thin film, and can be configured at low cost.

According to a second aspect of the present invention, there is provided a method of manufacturing an optical thin film using a magnetron sputtering method.
A first target is provided on the first electrode, a second target different from the first target is provided on the second electrode, and a second target is provided between the substrate and the first electrode. By adjusting the opening area of the first shutter provided on the substrate, the amount of the sputtered particles caused by the first target to reach the substrate was adjusted, and provided between the substrate and the second electrode. By adjusting the opening area of the second shutter to adjust the amount of sputter particles caused by the second target to reach the substrate, an optical thin film having a desired refractive index is manufactured on the substrate. It is assumed that.

According to the present invention, an optical thin film having a high degree of freedom in designing the refractive index can be efficiently formed on the substrate within a range determined by the materials of the first and second targets. A method for producing a thin film can be provided.

According to a third aspect of the present invention, there is provided an optical thin film wherein the refractive index is continuously changed in the thickness direction by continuously changing the opening areas of the first and second shutters during film formation. 3. The method for producing an optical thin film according to claim 2, wherein:

According to the present invention, in the method for manufacturing an optical thin film according to claim 2, by adopting a method of continuously changing the opening areas of the first and second shutters during film formation, It is possible to provide a method of manufacturing an optical thin film capable of efficiently forming an optical thin film whose refractive index continuously changes in the thickness direction.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the optical thin film manufacturing apparatus of the present invention will be described in detail.

Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. 1 showing the entire film forming system, FIG. 2 showing an enlarged shutter mechanism, and FIG. 3 showing an enlarged perspective view of a part of the film forming system. This will be described with reference to FIG.

(Configuration) First, the configuration of the entire film forming system of the optical thin film manufacturing apparatus will be described with reference to FIG. This optical thin film manufacturing apparatus includes a vacuum chamber 1 including a film forming system therein, a vacuum exhaust port 2 for performing vacuum evacuation of the inside of the vacuum chamber 1 by a vacuum exhaust system (not shown), and a vacuum chamber 1. A first magnetron sputtering electrode 4 as a first electrode attached, and a second magnetron sputtering electrode as a second electrode attached to the vacuum chamber 1 in a side by side arrangement with the first magnetron sputtering electrode 4. And an electrode 5. still,
In FIG. 1, reference numeral 3 indicates the direction of the exhaust performed from the vacuum exhaust port 2.

The first magnetron sputtering electrode 4 is provided with a sputtering target 6 as a first target of B-doped Si (4 inches in diameter), and a first power supply wiring 8 introduced from outside the vacuum chamber 1. Is connected to the first power source 10 via the power supply.

The first power source 10 has an industrial frequency 1
RF (Radio Frequency) at 3.65 MHz
y) an RF power source for applying power;
Magnetron sputter electrode 4 which is the target of
It consists of an auto-matching unit for supplying to the.

A sputtering target 7 of Ta (4 inches in diameter) is attached to the second magnetron sputtering electrode 5, and a second power source is supplied via a second power supply line 9 introduced from outside the vacuum chamber 1. 11 is connected.

Like the first power source 10, the second power source 11 includes an RF power source for applying RF power at an industrial frequency of 13.8 MHz and an automatic power source for efficiently supplying power to the electrodes. It consists of a matching unit.

The distance between the centers of the sputtering targets 6 and 7 is set to 20 cm.

Further, the optical thin film manufacturing apparatus has a piping for discharging an argon gas 13 as a sputtering gas supplied into the vacuum chamber 1 to the vicinity of the sputtering targets 6 and 7 while controlling the flow rate by a gas supply system (not shown). 12 and an oxygen gas 15 supplied into the vacuum chamber 1 while the flow rate is controlled by a gas supply system (not shown).
A pipe 14 for discharging to the upper part of the inside, a substrate holder 16 for holding a film-forming substrate 17, a motor 18 for rotating the substrate holder 16 at a constant speed, and a rotation of the motor 18 in the vacuum chamber 1. Rotating shaft 19 for transmitting to substrate holder 16
A sheath heater 20 provided around the substrate holder 16 to heat a film forming substrate 17 as a substrate;
And a shutter mechanism 22 as a second shutter attached to the second magnetron sputter electrode 5. The shutter mechanism 21 is a first shutter attached to the magnetron sputter electrode 4.

The substrate holder 16 has a disk shape with a diameter of 10 cm. Further, the sheath heater 20 is controlled by a thermocouple thermometer and a control unit (not shown) so that the film forming substrate 17 can be maintained at a constant temperature in a range of 150 to 350 degrees Celsius.

Next, FIGS. 2 and 3 (A), (B) and (C)
The configuration of the shutter mechanism 21 will be described with reference to FIG.
Since the shutter mechanism 22 has the same configuration as the shutter mechanism 21, the description of the configuration is omitted.

The shutter mechanism 21 includes a total of eleven elongated rectangular plates 23, a rotary shaft 24 provided at the center of each plate 23 in the longitudinal direction, and an end of the rectangular plate 23. It has a gear 25 directly connected to the rotating shaft 24 and a rotating shaft 26 having a screw gear on the outer periphery for rotating the gear 25.

The rotation shaft 26 is connected to a stepping motor 28 through a rotation introduction port 27 attached to the wall of the vacuum chamber 1. Stepping motor 2
Numeral 8 is fixed to the wall surface of the vacuum chamber 1, and its rotation operation is controlled by a control device (not shown). Arrows 29 in FIGS. 3A, 3B, and 3C indicate
This shows the direction in which sputtered particles are scattered from the sputtering target 6.

(Operation) Next, the operation of the first embodiment will be described.

First, the operation of the shutter mechanisms 21 and 22 will be described with reference to FIG. The shutter mechanism 21 has an opening area of the sputtering target 6 with respect to the substrate holder 16 by rotating a rectangular plate 23 about a rotation axis 24 and changing an angle with respect to a scattering direction 29 of sputter particles shown in FIG. Is changed to change the amount of sputtered particles scattered on the film-forming substrate 17.

The angular position of the rectangular plate 23 with respect to the scattering direction 29 of the sputtered particles is changed by rotating the stepping motor 28 by the control device (not shown).

That is, the screw gear 26 is rotated by the stepping motor 28, and the eleven gears 25 are rotated by the rotation of the screw gear 26, whereby the eleven rectangular plates 23 are rotationally driven, and the sputtering The angle with respect to the scattering direction 29 of the particles is changed.

Here, the screw gear 26 and the gear 25 are smoothly meshed with each other so that the backlash is negligible, and each of the rectangular plates 23 always takes the same angular position.

As shown in FIG. 2A, if the angle position of the rectangular plate 23 is parallel to the scattering direction 29 of the sputtered particles (interval a), the opening area of the sputtering target 6 with respect to the substrate holder 16 is maximum. Thus, the largest amount of sputtered particles sputtered on the sputtering target 6 reach the deposition substrate 17.

As shown in FIG. 2B, when the rectangular plate 22 overlaps the adjacent plate 22, the opening area becomes zero, and the sputtering target 6
Does not reach the film-forming substrate 17 at all.

An intermediate position (plate 23) as shown in FIG.
In the interval b), the opening area can be changed depending on the angle of the rectangular plate 23,
By changing the angular position of the rectangular plate 23, the amount of sputter particles sputtered on the sputtering target 6 reaching the deposition substrate 17 can be adjusted.

Next, a method for forming a thin film having an arbitrary refractive index using the shutter mechanisms 21 and 22 will be described.

After mounting a double-sided polished parallel flat glass (BK7) whose surface has been washed with an organic solvent on the substrate holder 16 as a film forming substrate 17, the inside of the vacuum chamber 1 is evacuated by using a vacuum exhaust device (not shown). Is evacuated from the vacuum exhaust port 2 in the direction 3. Seven minutes have elapsed since the evacuation by the evacuation device was started, and when the pressure inside the vacuum chamber 1 reached 1.0 × 10 ⁻¹ Pa, the power of the sheath heater 20 was turned on and the temperature was adjusted to 250 ° C. The heating of the film substrate 17 is started. further,
Thirty minutes after the evacuation by the evacuation apparatus was started, when the temperature of the film forming substrate 17 became constant at 250 degrees Celsius and the pressure inside the vacuum chamber 1 became 1.0 × 10 ⁻⁴ Pa or less, the sputtering gas Argon gas 13 of 30 sccm is introduced from the introduction pipe 12.

When the pressure in the vacuum chamber 1 is stabilized, the first power source 10 and the second power source 11
400 W of power is supplied to each of the magnetron sputtering electrode 4 and the second magnetron sputtering electrode 5 to generate plasma on the sputtering targets 6 and 7.

At this time, the shutter mechanisms 21 and 22
Both have a state in which the opening area is zero. While maintaining the state for 30 seconds, the surfaces of the sputtering targets 6 and 7 are pre-sputtered and cleaned.

At this point, the motor 18 is started and the substrate holder 16 is rotated to make the film thickness distribution on the film-forming substrate 17 uniform.

Next, the power supplied to the first magnetron sputtering electrode 4 was reduced to 300 W,
10 sccm of oxygen gas was introduced from the furnace, and the introduction amount of the argon gas 13 was reduced to 20 s of argon gas.
ccm.

After waiting for 10 seconds until the gas pressure stabilizes, the shutter mechanisms 21 and 22 are operated to change the angle of the rectangular plate 23 of the shutter mechanisms 21 and 22 to start film formation on the film forming substrate 17. I do. During film formation, the substrate holder 17 is driven to rotate at a constant speed. After performing the film formation for 3 minutes, the power supplied from the first and second power sources 10 and 11 to the first and second magnetron sputtering electrodes 4 and 5 is set to zero, and the film formation is completed.

Further, argon gas 13 and oxygen gas 1
After the amount of 5 introduced into the vacuum chamber 1 is reduced to zero, the inside of the vacuum chamber 1 is returned to the atmospheric pressure, and the film forming substrate 17 is taken out. Thereafter, the reflectance of the film-forming substrate 17 taken out was measured with a spectrophotometer, and the refractive index of the formed thin film was calculated. The relationship between the refractive index of the thin film obtained at this time and the angle of the rectangular plate 23 is shown in Table 1 below. In Table 1, the angle of the plate 23 is defined as an angle at which the rectangular plate 23 comes into contact with the adjacent rectangular plate 23 and the opening areas of the shutter mechanisms 21 and 22 become zero.

[0052]

[Table 1]

Using the configuration of the first embodiment,
It is possible to form a gradient refractive index film on the film forming substrate 17. In the procedure for obtaining a thin film having an arbitrary refractive index as described above,
Although the opening areas of the shutter mechanisms 21 and 22 were constant during film formation, the refractive index was changed by changing the opening area between the plates 23 of the shutter mechanisms 21 and 22 in conjunction with the progress of film formation. It is possible to obtain a thin film whose thickness continuously changes in the thickness direction.

For example, from the state where the angle of the plate 23 of the shutter mechanism 21 is 41 degrees and the angle of the plate 23 of the shutter mechanism 22 is 7 degrees, the plate angle of the shutter mechanism 22 is gradually reduced to 41 degrees.
Degree, and then the shutter mechanism 21
Is changed from 41 degrees to 0 degrees, a thin film whose refractive index continuously changes in the thickness direction from 1.51 to 2.14 can be obtained.

FIG. 7 shows the relationship between the optical film thickness and the refractive index of the optical thin film using such a thin film (gradient refractive index film) whose refractive index continuously changes in the thickness direction (Embodiment 1). (A)
Shown in FIG. 7 (B) shows the relationship between the optical film thickness and the refractive index of an optical thin film that does not use a gradient refractive index exemplified for comparison with the optical thin film using the gradient refractive index film (Comparative Example). It is.

FIG. 8 shows wavelengths of the optical thin films of the embodiment 1 (solid line) and the comparative example (dotted line) of 400 to 700 nm.
3 shows the reflectance characteristic in the range shown in FIG.

In the first embodiment, the elongated rectangular plate 23 is configured to rotate around the rotation shaft 24 provided at the center in the longitudinal direction. However, FIGS. 5, 6A and 6B show the configuration. As shown, even in a configuration in which the position of the rotation shaft 24 is changed to the end of the plate 23, the same operation as in the first embodiment can be exerted.

In the first embodiment, Si and Ta are used as the sputtering target materials. However, a thin film can be formed in the same manner by using a sputtering target material other than this combination, and an arbitrary refractive index can be obtained. A thin film can be obtained. In particular, as a sputtering target material for obtaining a high refractive index, in addition to Ta, Ti,
Nb is effective.

(Effect) According to the first embodiment, Si and
Using a Ta target, SiO_TwoAnd Ta _TwoO_FiveBlend of
Can form a composite film and has a refractive index range of 1.46 to 2.14
Thus, a thin film having an arbitrary refractive index can be obtained. Also,
It is also possible to create a thin film whose refractive index changes in the thickness direction,
The degree of freedom in designing an optical thin film can be increased.

[Second Embodiment] (Structure) Next, FIG. 9 is an enlarged perspective view of a part of a film forming system according to a second embodiment of the present invention, and FIG.
0 and FIG.

The structure of the second embodiment of the present invention is the same as that of the first embodiment except that the shutter mechanisms 21 and 22 in the first embodiment are replaced with other shutter mechanisms 30 and 31. Therefore, the shutter mechanisms 30, 3
Except for 1, the description is omitted.

In the second embodiment, the shutter mechanism 30 attached to the first magnetron sputtering electrode 4 and the shutter mechanism 31 attached to the second magnetron sputtering electrode 5 have the same configuration. The mechanism 30 will be described in detail below.

The shutter mechanism 30 includes a first grid plate 32 having a shape in which six divided grids are alternately formed with holes and shutter portions, and a second grid plate having a similar shape (cross-hatched). 33). One lattice of the first and second lattice plates 32, 33 is:
Each side is formed in a square of 18 mm.

The second grid plate 33 is fixed horizontally between the sputtering target 6 and the substrate holder 16, and the first grid plate 32 is movably mounted thereon in a horizontal direction.

A gear (not shown) is attached to the second lattice plate 33, and is connected to the rotating shaft 26 having the screw gear in the first embodiment.

The rotating shaft 26 is connected to a stepping motor 28 through a rotating shaft introduction port 27 attached to the wall of the vacuum chamber 1 as in the first embodiment. The stepping motor 28 is fixed to the wall surface of the vacuum chamber 1, and its rotation operation is controlled by a control device (not shown).

(Operation) Next, the operation of the second embodiment will be described.

First, the operation of the shutter mechanisms 30 and 31 will be described with reference to FIGS.
Will be described as an example.

The shutter mechanism 30 includes a first grid plate 32
Moves horizontally over the second grid plate 33 and changes the opening area from the sputtering target 6 to the substrate holder 16, thereby changing the amount of sputtered particles scattered on the deposition substrate 17.

The horizontal position of the first grid plate 32 is changed by rotating the stepping motor 28 by the control device (not shown). That is, the stepping motor 28 is started, and the screw gear 26
To rotate. The rotation of the screw gear 26 rotates a gear (not shown) attached to the first grid-like plate 32, whereby the first grid-like plate 32 moves horizontally, and the first grid-like plate 32 moves from the sputtering target 6 to the substrate holder 16. Change the opening area.

Here, the screw gear 26 and the gear are smoothly meshed with each other so that the backlash is negligible, and the first lattice plate 32 is repeatedly positioned with high accuracy in the horizontal direction by external control. Is performed.

As shown in FIG. 10, when the hole positions of the first grid plate 32 and the second grid plate 33 overlap each other, the opening area from the sputtering target 6 to the substrate holder 16 is maximized (see FIG. 10). 10 shows a white square), and the sputtered particles sputtered in the sputtering target 6 are the largest in number.
Reach 7

On the other hand, as shown in FIG. 11, when the hole positions of the first grid plate 32 and the second grid plate 33 do not overlap, the opening area becomes zero, and The sputtered particles that have been sputtered do not reach the deposition substrate 17 at all.

The procedure for obtaining a film having an arbitrary refractive index using the shutter mechanisms 30 and 31 is as follows.
1 is the same as that shown in Embodiment 1 except for the means for changing the opening area, and by changing the position of the first grid plate 32 belonging to each of the shutter mechanisms 30 and 31 to change the opening area. A thin film having an arbitrary refractive index can be obtained. The relationship between the refractive index of the obtained thin film and the angle of the rectangular plate 23 is shown in Table 2 below. Here, as shown in FIG. 11, the plate position where the opening area becomes 0 is 0 mm.

[0075]

[Table 2]

In the second embodiment, two six-divided grid-like plates 32 and 33 are used. However, the present invention is not limited to this.
Alternatively, similar film formation is possible even if a grid plate having five or less divisions is used. It is also possible to use three lattice-like plates 61, 62 and 63 as shown in FIG. The grid-like plate 61 is indicated by cross hatching, 62 is indicated by hatching, and 63 is indicated by dots.

Further, even if a shutter mechanism 67 for changing the opening area using two rectangular plates 69 and 70 as shown in FIG. 13 is employed, the same film formation can be performed.

In the form of the shutter mechanism described in the second embodiment, the thin film (gradient refractive index film) in which the refractive index continuously changes in the thickness direction shown in the first embodiment can be formed. It is possible.

Although Si and Ta are used as the sputtering target materials in the second embodiment, even if a sputtering target other than this combination is used,
Similarly, a mixed film can be formed, and an arbitrary refractive index can be obtained.

In particular, Ti and Nb other than Ta are effective as a sputtering target material for obtaining a high refractive index.

(Effect) According to the second embodiment, a mixed film of SiO ₂ and Ta ₂ O ₅ can be formed using a target of Si and Ta even if the structure of the shutter mechanism is changed.
A thin film having an arbitrary refractive index can be obtained in the refractive index range of 46 to 2.14. In addition, it is possible to form a thin film whose refractive index changes in the thickness direction, so that the degree of freedom in designing an optical thin film can be increased.

[Embodiment 3] (Configuration) Next, Embodiment 3 of the present invention will be described with reference to FIG. 14 in which the entire film forming system is viewed from above, FIG. This will be described with reference to FIG.

First, the configuration of the entire film forming system will be described with reference to FIG.

The film forming system of the optical thin film manufacturing apparatus shown in FIG. 14 includes a vacuum chamber 24 generally called a carousel type sputtering apparatus including a film forming system therein, and a first magnetron attached to the vacuum chamber 1. The sputtering electrode 35 and the second magnetron sputtering electrode 3 attached to the vacuum chamber 1
6 and an argon gas as a sputtering gas supplied while controlling the flow rate by a gas supply system (not shown).
And a pipe 39 for introducing the gas into the vicinity of the first sputtering target 37 in the direction of the arrow, and an argon gas supplied while the flow rate is controlled by a gas supply system (not shown).
A pipe 40 introduced into the vicinity of the first sputtering target 37 in the direction of the arrow and an argon gas supplied while controlling the flow rate by a gas supply system (not shown) are indicated by arrows 44.
, A pipe holder 43 for holding a film-forming substrate (not shown), a shutter mechanism 47 attached to the first magnetron sputtering electrode 35, and a second magnetron sputtering Electrode 36
And a shutter mechanism 48 attached to the camera.

The inside of the vacuum chamber 24 can be evacuated by a vacuum exhaust system (not shown).

The first magnetron sputtering electrode 35
For B-doped Si (5 inches × 20 inches ×
6.35 mmt) first sputtering target 3
7 is attached, and a first power source (not shown) arranged outside the vacuum chamber 24 is connected via a power introduction wiring (not shown).

The first power source includes a D for applying a negative voltage.
It comprises a C power source and an abnormal discharge suppressing unit for suppressing abnormal discharge.

The second magnetron sputtering electrode 36
For Ti (5 inch x 20 inch x 6.35 m
mt), a second sputtering target 38 is attached, and a second power source (not shown) arranged outside the vacuum chamber 34 is connected via a power introduction wiring (not shown).

The second power source 36, like the first power source 35, comprises a DC power source for applying a negative voltage and an abnormal discharge suppressing section for suppressing abnormal discharge.

The substrate holder 45 has a diameter of 85 cm × 9.
It is formed in a cylindrical shape of 0 cm, and is driven to rotate in the direction of arrow 46.

The shutter mechanism 47 has a rectangular plate 49.
And a plate 50 having the same shape as the rectangular plate 49, and a drive control mechanism for the rectangular plates 49 and 50 (not shown). The shutter mechanism 48 includes the shutter mechanism 4
7, the description of the configuration is omitted.

(Operation) Next, the operation of the third embodiment will be described.

First, the operation of the shutter mechanisms 47 and 48 will be described.
A description will be given taking one shutter mechanism 47 as an example.

The shutter mechanism 47 includes two rectangular plates 4
9 and 50 are moved in parallel to the first sputtering target 37 by a drive control mechanism (not shown), whereby the first
By changing the opening area from the sputtering target 37 to the substrate holder 45, the scattering amount of sputtered particles on the film formation substrate (not shown) is changed.

When the distance between the two rectangular plates 49 and 50 is the longest, the most sputtered particles from the first sputtering target 37 reach the film forming substrate (not shown). I do.

On the other hand, when the distance between the two rectangular plates 49 and 50 is zero, sputter particles sputtered from the sputtering target 37 do not reach the film-forming substrate (not shown) on the substrate holder 45 at all. .

In the intermediate position where the distance between the two rectangular plates 49 and 50 is as described above, by changing the opening area, the sputtered particles sputtered on the first sputtering target 37 can be reduced. The amount reaching the film formation substrate can be arbitrarily adjusted.

When a thin film having an arbitrary refractive index is to be obtained by using the shutter mechanisms 47 and 48, the film deposition substrate is placed on the substrate holder 45 in the same manner as in the first embodiment. After setting, the inside of the vacuum chamber 34 is evacuated by a vacuum exhaust system (not shown).

When the pressure inside the vacuum chamber 34 is 1.0 × 1
When the pressure becomes 0 ^-4 Pa or less, the shutter mechanisms 47, 4
8 is in a state where the opening area is zero,
9 and 40, argon gas is introduced from each of the first and second power sources (not shown).
Power is supplied to each of the magnetron sputtering electrode 35 and the second magnetron sputtering electrode 36 to pre-sputter and clean the surfaces of the first and second sputtering targets 37 and 38. At this point, the rotation of the substrate holder 45 in the direction of the arrow 46 is started.

Next, introduction of oxygen gas 44 from the pipe 43 toward the substrate holder 45 is started. Here, a thin film having a desired refractive index can be obtained by operating the shutter mechanisms 47 and 48 by a drive control mechanism (not shown) to control the respective aperture areas to desired values.

In the third embodiment, a thin film having an arbitrary refractive index can be freely obtained as long as the refractive index is between the refractive index of SiO ₂ (1.46) and the refractive index of TiO ₂ (2.35). be able to.

When the target film thickness is obtained on the film-forming substrate, the power supplied to the first magnetron sputtering electrode 35 and the second magnetron sputtering electrode 36 is set to zero, and the film formation is completed.

Further, after the introduction amounts of the argon gas and the oxygen gas into the vacuum chamber 34 were reduced to zero, the inside of the vacuum chamber 34 was returned to the atmospheric pressure, and the arbitrary film-forming substrate (not shown) was taken out. The manufacture of the thin film having the refractive index is completed.

Also in the carousel type film forming apparatus shown in the third embodiment, the refractive index is changed in the same manner as in the first embodiment by gradually changing the opening areas of the shutter mechanisms 47 and 48 during the film formation. It is possible to produce a thin film (gradient refractive index film) in which the thickness changes continuously in the thickness direction.

Further, in the third embodiment, Si and Ti are used as the sputtering target materials. However, in a sputtering target material other than this combination, a mixed film is similarly formed to obtain a thin film having an arbitrary refractive index. be able to. In particular, Ta and Nb other than Ti are effective as a sputtering target material for obtaining a high refractive index.

(Effect) According to the third embodiment, by using a carousel type sputtering apparatus and a sputtering target of Si and Ti, SiO ₂ and T
A mixed film of iO ₂ can be formed. In addition, it is possible to form a thin film in which the refractive index changes by changing the mixing ratio in the thickness direction, thereby increasing the degree of freedom in designing the optical thin film.

The present invention relates to a rugate filter (Rug).
a filter, an antireflection film, and the like.

Further, according to the present invention, an optical thin film having a desired refractive index can be manufactured with high accuracy over a wide refractive index range, and a thin film having an intermediate refractive index and the refractive index change in the thickness direction. A thin film can be obtained. Thus, the degree of freedom in designing the optical thin film can be greatly increased.

An apparatus for carrying out the present invention can be realized by adding a new shutter mechanism to a sputtering apparatus which has been used for ordinary film formation so far. There is also the advantage that no expensive equipment is required.

According to the present invention described above, the following configuration can be added. (Supplementary Note 1) Two magnetron sputter electrodes including a first magnetron sputter electrode having a sputtering target material and a second magnetron sputter electrode having a sputtering target material different from the sputtering target material are provided. By providing a means for introducing an inert gas as a sputtering gas from the vicinity of the sputtering targets toward the discharge region, and by providing a power input means capable of simultaneously applying an input voltage to each of the magnetron sputtering electrodes. ,
A discharge is simultaneously generated in the first magnetron sputter electrode and the second magnetron sputter electrode, and a film is deposited on a film formation substrate by the first magnetron sputter electrode, and a film is formed by the second magnetron sputter electrode. In the optical thin film forming apparatus capable of forming a thin film in which the two sputtering target materials are mixed by simultaneously or sequentially depositing the films on the substrate, the opening area from the sputtering target material to the substrate is arbitrary. Wherein the shutter mechanism is provided independently between the electrodes and the substrate, and the shutter mechanism is controlled so that the opening area can be arbitrarily set and continuously changed. Thin film manufacturing equipment.

In the configuration of Appendix 1, when power is simultaneously supplied to the two magnetron sputtering electrodes and two sputtering target materials are simultaneously deposited on the film forming substrate,
The resulting film is a mixed film of the two sputtering target materials.

Since the sputtering target attached to the magnetron sputtering electrode in Appendix 1 is made of a material having a different refractive index of the oxide thin film when a single thin film is formed, the refractive index of the obtained mixed film is two sputtering target materials. Is any value between the refractive indices of.

The refractive index of the mixed film can be changed by the mixing ratio of the sputtering material. In Supplementary Note 1, by using a shutter capable of changing the opening area and a mechanism capable of controlling the shutter to set the opening area arbitrarily and changing the opening area continuously, the sputtering target can be changed from each sputtering target to the film forming substrate. By adjusting the amount per unit time to reach, to obtain a film having an arbitrary refractive index by arbitrarily changing the mixing ratio, or by continuously changing the mixing ratio, the refractive index is continuously in the thickness direction. Can be obtained.

In order to arbitrarily change the mixing ratio, the opening area of the shutter is 0 (when the shutter is completely closed).
It is necessary to be able to arbitrarily change as much as possible so that there is little obstruction between the sputtering target and the film formation substrate. Changing the opening area from 0 (when the shutter is completely closed) corresponds to the case where the mixing ratio of one material is small, and the film material reaches the substrate during cleaning (pre-sputtering) of the sputtering target surface. Required to avoid.

The reason why the opening area of the shutter is changed to a state in which there is little obstruction between the sputtering target and the film formation substrate is because it is advantageous to increase the forming speed of the thin film.

In order to increase the degree of freedom in designing the optical thin film and to easily obtain desired optical characteristics, the combination of the sputtering targets made of different materials in Appendix 1 is used for a material having a larger refractive index difference. Combinations are preferred. In addition, using Si as a material for obtaining a low-refractive-index oxide and using Ti, Nb, or Ta as a material for obtaining a high-refractive-index oxide is more effective in obtaining a large refractive index difference. preferable. Introducing a sputtering gas from the vicinity of the sputtering target toward the discharge region helps stabilize the discharge even in a state where the film formation atmosphere has a low degree of vacuum. The sputtering gas used here is preferably an inert gas having a high sputtering rate, particularly Ar.

(Supplementary Note 2) The sputtering target is a sputtering target made of a metal or a semiconductor that becomes a transparent oxide in the visible region when oxidized. 2. The apparatus for producing an optical thin film according to claim 1, further comprising means for introducing a gas containing oxygen as a reactive gas.

As described in Supplementary Note 2, using a metal or a semiconductor as the sputtering target material is effective in increasing the film forming rate because the metal or the semiconductor has a high sputtering rate.

Introducing a sputtering gas from the vicinity of the two sputtering targets toward the discharge region is necessary in reactive sputtering in order to sputter the sputtering target material as it is with a metal or a semiconductor. Helps to stabilize the discharge. The sputtering gas used here is preferably an inert gas having a high sputtering rate, particularly Ar.

By introducing a gas containing oxygen as a reactive gas into the film formation atmosphere from a position different from the above-mentioned sputtering gas, the semiconductor or metal reaching the film formation substrate is sufficiently oxidized to obtain a transparent film. Indispensable for.

The reactive gas is preferably introduced from the vicinity of the film forming substrate toward the film forming substrate in order to more reliably oxidize the semiconductor or metal that has reached the film forming substrate. Compound gas such as CO ₂ as the gas containing oxygen, N _2, although a mixed gas of O ₂ are considered,
In the case where there is no problem such as restricting the vacuum evacuation device from flowing only oxygen, it is preferable to use high-purity oxygen in order to obtain a high-quality film.

The fact that input power can be simultaneously applied to each magnetron sputtering electrode is twofold.
This is an essential requirement for mixing different types of materials.

(Supplementary Note 3) In the method of manufacturing an optical thin film using the optical thin film manufacturing apparatus of Supplementary Note 1, a thin film having a desired refractive index is obtained by arbitrarily adjusting an opening area of a shutter. Manufacturing method of optical thin film. Appendix 3
According to the method, a thin film having a desired refractive index can be efficiently manufactured by adjusting the opening area of the shutter.

(Supplementary note 4) In the method of manufacturing an optical thin film using the optical thin film manufacturing apparatus of Supplementary note 1, the refractive index can be continuously changed in the thickness direction by continuously changing the opening area of the shutter in Supplementary note 1. A method for producing an optical thin film, comprising obtaining a changed thin film. According to Appendix 4, a thin film in which the refractive index is continuously changed in the thickness direction can be efficiently manufactured.

(Supplementary Note 5) In an optical thin film manufacturing apparatus for forming an optical thin film on a substrate by magnetron sputtering, a first electrode for disposing a first target is different from the first target. A second electrode for disposing a second target; the substrate and the first electrode;
A first electrode for adjusting the amount of sputtered particles caused by the first target that reaches the substrate, provided between the first target and the first electrode.
And a second shutter that is provided between the substrate and the second electrode and that adjusts the amount of sputtered particles caused by the second target to reach the substrate. Optical thin film manufacturing equipment. According to Supplementary Note 5, the range of the refractive index of the optical thin film formed on the substrate can be expanded to the entire range determined by the materials of the first and second targets, and the design of the refractive index of the optical thin film can be improved. It is possible to provide an optical thin film manufacturing apparatus that has a large degree of freedom and can be configured at low cost.

(Supplementary Note 6) The apparatus for producing an optical thin film according to supplementary note 5, wherein the shutter is constituted by a plurality of plate members rotating about an axis provided substantially perpendicular to a line connecting the substrate and the electrode. According to Supplementary Note 6, there is provided an optical thin film manufacturing apparatus capable of inexpensively manufacturing an optical thin film having a large degree of freedom in designing a refractive index using a shutter using a plurality of plate members rotating about the axis. be able to.

(Supplementary Note 7) The shutter is constituted by a plurality of plate members provided with openings and closing portions alternately.
An apparatus for producing the optical thin film according to the above. According to Supplementary Note 7, manufacturing of an optical thin film capable of inexpensively forming an optical thin film having a large degree of freedom in designing a refractive index using a shutter constituted by a plurality of plate members having openings and closing portions alternately provided. An apparatus can be provided.

(Supplementary Note 8) The apparatus for producing an optical thin film according to supplementary note 5, wherein the shutter is constituted by a plurality of plate members which can be separated from and separated from each other. According to Supplementary Note 8, it is possible to provide an optical thin film manufacturing apparatus capable of inexpensively forming an optical thin film having a large degree of freedom in designing a refractive index by using a shutter constituted by a plurality of plate members which can be separated from each other. .

(Supplementary note 9) The apparatus for producing an optical thin film according to supplementary note 5, wherein the optical thin film is a functionally graded material whose optical characteristics continuously change in the thickness direction.

(Supplementary note 10) The apparatus for producing an optical thin film according to supplementary note 9, wherein the optical characteristic is a refractive index. According to Supplementary Notes 9 and 10, it is possible to manufacture an optical thin film whose optical properties, that is, the refractive index continuously changes in the thickness direction.

[0131]

According to the first aspect of the present invention, when forming an optical thin film on a substrate by magnetron sputtering, the first and second shutters allow the sputtered particles caused by the first target to be formed. The simple means of adjusting the amount of the sputtered particles originating from the second target to the substrate by the second shutter while adjusting the amount of the optical thin film formed on the substrate is adjusted by the second shutter. Provided is an optical thin film manufacturing apparatus that can extend the range of the refractive index to the entire range determined by the materials of the first and second targets, has a high degree of freedom in designing the refractive index of the optical thin film, and can be configured at low cost. can do.

According to the invention described in claim 2, on the substrate,
It is possible to provide a method of manufacturing an optical thin film capable of efficiently forming an optical thin film having a high degree of freedom in designing a refractive index within a range determined by the materials of the first and second targets.

According to the third aspect of the present invention, it is possible to provide a method of manufacturing an optical thin film capable of efficiently forming an optical thin film whose refractive index continuously changes in the thickness direction.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an entire film forming system of an optical thin film manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a shutter mechanism of the optical thin film manufacturing apparatus according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a part of a shutter mechanism of the optical thin film manufacturing apparatus according to the first embodiment of the present invention, and FIG.
3B shows a state where the opening area is the maximum, FIG. 3B shows a state where the opening area is the minimum, and FIG. 3C shows a state where the opening area is adjusted.

FIG. 4 is an enlarged perspective view of a film forming system according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a modification of the shutter mechanism according to the first embodiment of the present invention.

6A and 6B are diagrams showing a modification of the shutter mechanism according to the first embodiment of the present invention. FIG. 6A shows a state in which the opening area is maximum, and FIG. 6B shows a state in which the opening area is minimum. It is shown.

FIG. 7 shows the relationship between the optical film thickness and the refractive index of the optical thin film according to the first embodiment of the present invention (FIG. 7A) and the relationship between the optical film thickness and the refractive index of the comparative example (FIG. It is a characteristic view which shows B)).

FIG. 8 is a graph showing the reflectance characteristics of the optical thin films of Embodiment 1 (solid line) and Comparative Example (dotted line) of the present invention in the wavelength range of 400 to 700 nm.

FIG. 9 is an enlarged perspective view of a film forming system according to a second embodiment of the present invention.

FIG. 10 is a schematic diagram showing a shutter mechanism according to Embodiment 2 of the present invention.

FIG. 11 is a schematic view showing a shutter mechanism according to the embodiment of the present invention.

FIG. 12 is a schematic diagram showing an open state (FIG. 12A) and a closed state (FIG. 12B) of a modified example of the shutter mechanism according to the second embodiment of the present invention.

FIG. 13 shows an open state (FIG. 12A) and a closed state (FIG. 12) of another modified example of the shutter mechanism according to the second embodiment of the present invention.
It is a schematic diagram showing (B)).

FIG. 14 is a schematic plan view illustrating an optical thin film manufacturing apparatus according to a third embodiment of the present invention.

FIG. 15 is a partial perspective view showing an open state of the plate (FIG. 13A) and an adjusted state of the plate (FIG. 13B) in the film forming system according to Embodiment 3 of the present invention.

FIG. 16 is a partial perspective view showing a film forming system according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum tank 4 1st magnetron sputter electrode 5 2nd magnetron sputter electrode 6 Sputtering target 7 Sputtering target 8 1st power supply wiring 9 2nd power supply wiring 10 1st power source 11 2nd power source 12 Piping 14 Piping 16 Substrate holder 17 Deposition substrate 18 Motor 19 Rotating shaft 20 Sheath heater 21 Shutter mechanism 22 Shutter mechanism 23 Plate 24 Rotating shaft 25 Gear 26 Screw gear 27 Rotation introduction port 28 Stepping motor 30 Shutter mechanism 31 Shutter mechanism

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Ikeda 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (72) Kiyoshi Takao 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Takeshi Ken Kawamata 2-34-2 Hatagaya, Shibuya-ku, Tokyo F-term within Olympus Optical Co., Ltd. (Reference) 2K009 AA00 CC02 DD04 4K029 BC07 CA05 DA13 DC16

Claims (3)

[Claims] In an optical thin film manufacturing apparatus for forming an optical thin film on a substrate by a magnetron sputtering method, a first electrode for disposing a first target is different from the first target. A second electrode for disposing a second target; and a first electrode provided between the substrate and the first electrode;
A first shutter for adjusting the amount of sputter particles that reach the substrate caused by the target; and a second shutter provided between the substrate and the second electrode;
And a second shutter for adjusting an amount of sputtered particles caused by the target to reach the substrate. 2. A method of manufacturing an optical thin film using a magnetron sputtering method, wherein a first target is disposed on a first electrode, and a second target different from the first target is disposed on a second electrode. The amount of sputter particles caused by the first target reaching the substrate by adjusting the opening area of a first shutter provided between the substrate and the first electrode. By adjusting the opening area of a second shutter provided between the substrate and the second electrode, the amount of sputter particles caused by the second target reaching the substrate is adjusted. And manufacturing an optical thin film having a desired refractive index on the substrate. 3. An optical thin film having a refractive index continuously changed in a thickness direction by continuously changing an opening area of the first and second shutters during film formation. The method for producing an optical thin film according to claim 2, wherein