JPH09165671A - Vapor deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform vapor deposition without generating hexavalent chromium in the vacuum deposition of Cr2 O3 by vaporizing Cr in an oxygen atmosphere. SOLUTION: A substrate and a sample (Cr) are set as conventional, evacuation is started, the substrate is heated, the arrival at a target vacuum is confirmed, and further, the substrate temp. is confirmed. Oxygen is then introduced to fill the vacuum device with an oxygen atmosphere. The gaseous oxygen is introduced so that the entire vacuum is controlled between 1×(1-10)<4> and 2×(1/10)<4> millibar. After the target oxygen atmosphere is attained, the sample (Cr) vaporized with an electron gun to form a Cr2 O3 film on the substrate surface. When such vapor deposition is performed, hexavalent chromium is not detected.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vapor deposition method, and more particularly to a vacuum vapor deposition method for Cr ₂ O ₃ .

[0002]

_2. Description of the Related Art A conventional vacuum deposition method of Cr ₂ O ₃ comprises a flow as shown in FIG. Each flow will be described below.

A) Evacuation start When the setting of the substrate and vapor deposition material is completed, evacuation is started.

B) Substrate heating Substrate heating is performed in order to stabilize the optical properties such as the refractive index of the vapor deposition material and the reliability of the film. In some cases, the substrate may not be heated.

C) Reaching the target vacuum degree It is confirmed that the target vacuum degree has been exhausted according to the set conditions. Normally, exhaust is performed up to 1 × (1/10) ⁵ mbar.

D) Substrate temperature confirmation It is confirmed that the substrate temperature has reached the target temperature according to the set conditions.

E) Evaporation of Cr ₂ O ₃ .

Cr ₂ O ₃ is evaporated as a material. The vapor deposition method at this time includes a method using an electron gun and a method using a resistance heating boat.

F) A Cr ₂ O ₃ film is formed on the substrate.

A Cr ₂ O ₃ film is formed on the substrate.

[0011]

Cr ₂ O _{3 is produced by the} conventional method.
When the vacuum vapor deposition is performed, a large amount of hexavalent chromium is generated during the vapor deposition. Therefore, hexavalent chromium is not only on the substrate,
It also adheres to jigs such as vapor deposition domes and holders, and the outer wall of the device, and has a great adverse effect on the environment. For this reason, an apparatus for removing hexavalent chromium is required, and a step of using an apparatus for removing hexavalent chromium must be added during the vacuum deposition step, which will increase the cost of the lens in the future. It was

[0012]

According to the vapor deposition method of the present invention for solving the above-mentioned problems, in a vacuum vapor deposition process in which Cr ₂ O ₃ is vapor-deposited on a substrate in a vacuum apparatus, vacuum exhaust is performed to obtain a target degree of vacuum. After reaching the temperature, oxygen is introduced and Cr in an oxygen atmosphere.
Is vaporized to form a Cr ₂ O ₃ film on the substrate.

According to the method of the present invention, hexavalent chromium is not detected after depositing Cr ₂ O ₃ . Further, hexavalent chromium is not detected not only from the Cr ₂ O ₃ film on the substrate but also from the residue of the vapor deposition material.

[0014]

EXAMPLE A vapor deposition method of the present invention will be described below with reference to FIGS. FIG. 16 is a diagram of a vacuum vapor deposition apparatus used in the present invention. Using this apparatus, the substrate is vapor-deposited according to the flow shown in FIG. FIG. 16A shows a type in which a sample (Cr) is evaporated by an electron gun.

A) After placing the substrate 4 on the evaporation dome 3, the sample 6 is set on the electron gun 7. Then, the vacuum device is operated to start exhausting.

B) Next, the substrate 4 is heated by the heater for heating the substrate. In this embodiment, the target temperature is 3
00 degrees. This process is performed when necessary.

C) Confirm that the target vacuum level has been reached. Normally, exhaust is performed up to 1 × (1/10) ⁵ mbar.

D) Check if the substrate has reached the target temperature.

E) Next, oxygen gas is introduced from the oxygen inlet 5 to make the inside of the vacuum apparatus an oxygen atmosphere. The oxygen gas preferably has a total vacuum degree of 1 × (1/10) ⁴ mbar to 2
× (1/10) ⁴ mbar to be introduced.
At this time, if the oxygen atmosphere exceeds 2 × (1/10) ⁴ mbar, especially 4 × (1/10) ⁴ mbar,
It is not desirable because it damages the vacuum pump (oil diffusion pump). Furthermore, if vapor deposition is performed in complete oxygen, the sample will be oxidized or burned, and vapor deposition itself will be impossible. Also, the degree of vacuum is 1 × (1/10) ⁶ mbar
And the oxygen atmosphere is 1-2 x (1/10) ⁵ mba.
Hexavalent chromium is hard to be generated even if it is about r. However, it takes too much time to attain this degree of vacuum and is not practical.

F) After reaching the target oxygen atmosphere, the sample 6 is evaporated by the electron gun 7.

G) As a result, Cr ₂ is formed on the surface of the substrate 4.
An O ₃ film is formed. At this time, the film thickness is monitored by the film thickness monitor 1 until the required film thickness is reached.
When the required film thickness is reached, vapor deposition is completed.

FIG. 16 (b) is a view showing a case where the resistance heating boat 8 is used for evaporation of the sample, and other than that, FIG.
Same as (a).

Next, when the vapor deposition according to the present invention is performed,
FIG. 3 shows a list of the results of vapor deposition when the vapor deposition was performed by the conventional method and when the vapor deposition was performed by the improved method of the conventional method. According to the conventional method, the generation rate of hexavalent chromium reaches 20%.
There are two methods that have been examined as these improvement measures. It is a method of increasing the deposition rate and a method of increasing the degree of vacuum. However, in both cases, 10% of hexavalent chromium is generated. However, when the vapor deposition according to the present invention was performed, hexavalent chromium was not detected.

Then, Cr ₂ O ₃ is deposited by this vapor deposition method.
We will compare the performance when an antireflection coat using is used.

FIG. 4 is a view showing the film thickness constitution of a conventional antireflection coat which does not use Cr ₂ O ₃ and the incident angle dependence with respect to a wavelength of 780 nm. In addition, according to FIG.
The incident angle dependence for 80 nm is graphed. The film composition is the first layer SiO ₂ film 128.2 nm, the second layer
It is a three-layer coat composed of a layer Si film 45.2 nm and a third layer Cr film 200 nm. The dependency on the incident angle at this time is such that the reflectance becomes higher when the incident angle exceeds 40 degrees. If the incident angle exceeds 55 degrees, the reflectance exceeds 30%, which makes it difficult to withstand practical use.

FIG. 5 shows Cr_TwoO_ThreeAntireflection of Example 1 using
Film thickness composition of stop coat and incidence for wavelength 780nm
It is a figure which shows an angle dependence. In addition, according to FIG.
The incident angle dependence for 80 nm is graphed
You. The film composition is the first layer (TiO 2 _Two+ ZnO_Two) Membrane 41.7
nm, second layer TiO_TwoFilm 38nm, third layer Cr_TwoO_ThreeMembrane 1
A four-layer coating consisting of 80 nm and a fourth-layer Cr film of 20 nm
is there. The dependency on the incident angle at this time is that the incident angle is 35 degrees.
Although it shows a very small increase in reflectance at
The reflectivity is very low, less than 10%.
It has excellent reflectance characteristics. In addition, a practical limit of reflectance of 30
% Is actually exceeded after the incident angle exceeds 80 degrees.
You.

FIG. 6 is a diagram showing the film thickness constitution of the antireflection coating of Example 2 using Cr ₂ O ₃ and the incident angle dependence on the wavelength of 780 nm. Further, according to FIG. 12, the wavelength 7
The incident angle dependence for 80 nm is graphed. The film constitution is the first layer (TiO ₂ + ZnO ₂ ) film 41.7.
nm, second layer Al ₂ O ₃ film 54 nm, third layer TiO ₂ film 3
8 nm, 4th layer Cr ₂ O ₃ film 240 nm, 5th layer Cr film 2
It is a 5-layer coat consisting of 0 nm. The dependency on the incident angle at this time is that the reflectance is 10 up to the incident angle of 75 degrees.
It has a very flat reflectance characteristic of not more than%. Further, the practical limit of the reflectance of 30% is actually exceeded when the incident angle further exceeds 80 degrees.

FIG. 7 is a diagram showing the film thickness constitution of the antireflection coating of Example 3 using Cr ₂ O ₃ and the incident angle dependence on the wavelength of 780 nm. In addition, according to FIG.
The incident angle dependence on 0 nm is graphed.
The film constitution is the first layer (TiO ₂ + ZnO ₂ ) film 65.3n.
m, second layer Al ₂ O ₃ film 82.1 nm, third layer TiO ₂ film 57.8 nm, fourth layer Cr ₂ O ₃ film 50 nm, fifth layer Cr
It is a 5-layer coat consisting of a film of 20 nm. The dependence on the incident angle at this time shows that the reflectance increases once to nearly 20% at an incident angle of 35 degrees, but in other cases, the reflectance is 10% or less until the incident angle of 80 degrees, which is a very flat reflectance. Have characteristics. In addition, the practical use reflectance of 30% is not exceeded, and the reflectance is actually 20% up to an incident angle of 85 degrees.
The following reflectance characteristics can be obtained.

FIG. 8 is a diagram showing the film thickness constitution of the antireflection coating of Example 4 using Cr ₂ O ₃ and the incident angle dependence on the wavelength of 780 nm. In addition, according to FIG.
The incident angle dependence on 0 nm is graphed.
The film constitution is the first layer (TiO ₂ + ZnO ₂ ) film 16.7n
m, second layer Cr ₂ O ₃ film 150 nm, third layer Si film 57n
and a fourth layer Cr film of 20 nm.
The dependency on the incident angle at this time shows that the reflectance increases once to nearly 20% at the incident angle of 35 degrees, but in other cases, the reflectance is 10% or less until the incident angle of 65 degrees, which is a very flat reflectance. Have characteristics. Also, the incident angle is 75
Up to 30 degrees, a reflectance characteristic of a reflectance of 30% or less can be obtained.

FIG. 9 is a view showing the film thickness constitution of the antireflection coating of Example 5 using Cr ₂ O ₃ and the incident angle dependence on the wavelength of 780 nm. In addition, according to FIG.
The incident angle dependence on 0 nm is graphed.
The film constitution is the first layer (TiO ₂ + ZnO ₂ ) film 17.3n.
m, second layer Cr ₂ O ₃ film 150 nm, third layer Si film 52n
and a fourth layer Cr film of 20 nm.
The dependence on the incident angle at this time shows that the reflectance increases once to nearly 20% at the incident angle of 35 degrees, but in other cases, the reflectance is 10% or less until the incident angle of 65 degrees, which is a very flat reflectance. Have characteristics. Also, the incident angle is 75
Up to 30 degrees, a reflectance characteristic of a reflectance of 30% or less can be obtained.

FIG. 17 shows a multilayer film having a four-layer structure as an example of the multilayer film. On the substrate 10, the multilayer coat 9 is composed of a first layer, a second layer, a third layer, and a fourth layer from the side closer to the substrate 10. The present embodiment having such a configuration is Embodiment 1, Embodiment 4, and Embodiment 5. The number of layers in this membrane may be changed at any time depending on the need and design.

Next, the difference in the case where the antireflection coating is applied to the mirror surface and the pick-up surface will be described. The mirror surface is polished so that the surface of the substrate becomes a very flat plane. Further, the pickpocket surface is a surface that is as it is when the substrate is produced or is roughly roughened.

FIG. 18 shows an example in which an antireflection coating 9 is applied to a substrate 10 having a mirror surface. Incident light 11 is incident on the substrate 10 at an incident angle 14. At this time, the reflected light 13 and the emitted light 12 are separated at the boundary between the substrate 10 and the multilayer coat 9. At this time, the reflected light 13 is the incident light 1
This is a return light to the 1 side, which is extremely undesirable.
Therefore, even if the conventional multi-layer coating shown in FIGS. 4 and 10 is applied to the substrate 10 on which the incident light 11 having various incident angles is incident, there is no adverse effect due to the reflected light 13 of the incident light 11 having a large incident angle. Inevitable. However, Example 1
If the multilayer coats shown in to 5 are performed, the adverse effect of the reflected light 13 can be suppressed as much as possible.

FIG. 19 is a diagram showing reflection when the incident light 11 comes from a fixed direction. FIG. 19A shows a case where the substrate has a picked surface, and FIG. 19B shows a case where the substrate has a mirror surface. In both figures, the multilayer coat 9 and the emitted light 12 are not shown. Further, although the reflected light 13 seems to be reflected from a position different from the incident light 11, this is a notation that is easy to understand in the drawing, and originally, it is incident and reflected at the same point.

In FIG. 19B, since the incident angle of the incident light 11 is constant, the reflected lights 13 (c) are all in the same direction. Therefore, it suffices if this incident angle is small, and thus the incident angle 14 may be made small by applying a conventional coating.

In FIG. 19A, since the reflecting surface is a slip surface, the incident angle 14 is not constant. Therefore, the reflected lights 13 (a) and 13 (b) having different reflection directions are generated.
Therefore, if the conventional coating is performed, it is affected by the return light due to reflection. Here, Examples 1 to 5
By applying a multi-layer coating using Cr ₂ O ₃ as described above, it is possible to provide a very good antireflection property even for a wide range of incident angles.

FIG. 20 shows an example of a prism in which the reflecting surface 15 is a picked surface. Incident light 11 enters the prism and emerges light 1
It is divided into 2 and reflected light 13. The reflected light 13 becomes further returned light 16 on the reflection surface 15 and returns to the incident light 11 side. This has a great adverse effect on the incident light side. Therefore, it becomes necessary to apply a multilayer coat here. Here, a conventional multi-layer coating may be performed,
The effect decreases as the angle of incidence increases. Therefore, by applying a multi-layer coat using Cr ₂ O _{3 according} to this embodiment, it is possible to have very good reflection characteristics. Further, the reflecting surface 15 may be a picked surface. This means that one surface of the prism does not have to be mirror-polished, which brings about very favorable effects such as cost reduction and work process reduction.

[0038]

According to the method of the present invention, Cr ₂ by vapor deposition is used.
In forming the O ₃ film, the vapor deposition is completed without generating hexavalent chromium.

[Brief description of the drawings]

[Figure 1] Deposition process according to the conventional flow

FIG. 2 is a vapor deposition process according to the flow of the present invention.

FIG. 3 is a difference between a conventional method and the present invention

FIG. 4 Example of conventional multilayer coat and performance

FIG. 5: Multilayer coat and performance of Example 1

FIG. 6 Multilayer coat and performance of Example 2

FIG. 7: Multilayer coat and performance of Example 3

FIG. 8: Multilayer coat and performance of Example 4

FIG. 9: Multilayer coat and performance of Example 5

FIG. 10 is a performance graph of an example of a conventional multilayer coat.

11 is a performance graph of the multilayer coat of Example 1. FIG.

FIG. 12 is a performance graph of the multilayer coat of Example 1.

FIG. 13 is a performance graph of the multilayer coat of Example 1.

14 is a performance graph of the multilayer coat of Example 1. FIG.

15 is a performance graph of the multilayer coat of Example 1. FIG.

FIG. 16 is an apparatus diagram of the present invention.

FIG. 17 is an explanatory diagram of a multi-layer coat

FIG. 18 is an explanatory diagram of reflected light

FIG. 19 is an explanatory diagram of light reflected by a picked surface and a mirror surface.

FIG. 20: Example of prism suitable for applying the present invention

[Explanation of symbols]

 1 Film Thickness Monitoring Monitor 2 Substrate Heating Heater 3 Deposition Dome 4 Substrate 5 Oxygen Gas Inlet 6 Sample 7 Electron Gun 8 Resistance Heating Boat 9 Multilayer Coat 10 Substrate 11 Incident Light 12 Emitted Light 13 Reflected Light 14 Incident Angle 15 Reflection Surface 16 Return light

Claims (1)

[Claims] 1. In a vacuum deposition process for depositing Cr ₂ O _{3 on} a substrate in a vacuum apparatus, after evacuation to reach a target vacuum degree, oxygen is introduced and Cr is evaporated in an oxygen atmosphere. And a Cr ₂ O ₃ film is formed on the substrate.