JP2000104161A - Method for controlling refractive index of dry plating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely produce a thin film mainly having a refractive index in a specified range on a base material by executing plating in such a manner that silicon carbide is used as a raw material source, and reactive gas is controlled. SOLUTION: The surface of a base material is provided with a thin film having an optional refractive index in the range of 1.4 to 2.8. Preferably, reactive gas is composed of gas contg. oxygen and/or contg. nitrogen, moreover, the reactive gas ratio [the flow rate of the reactive gas/(the flow rate of the reactive gas + the flow rate of inert gas) × 100] is controlled to the range of 0 to 50%, furthermore, dry plating is sputtering, moreover, a mixture in which silicon carbide as a raw material source has >=2.9 g/cm3 density, and silicon carbide powder and a nonmetallic sintering assistant are homogeneously mixed is sintered. Since the SiC target material using the silicon carbide sintered body has electric conductivity, DC sputtering or DC magnetron sputtering is preferably executed, and, as the base material, glass, ceramic, a metallic material, PMMA, PET or the like can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a refractive index of a dry plating film, which can reliably produce a thin film having an arbitrary refractive index by a dry plating method.

[0002]

2. Description of the Related Art
In order to obtain an arbitrary refractive index, an oxide film is generally used, but the refractive index of the oxide film does not change significantly even when the oxygen fraction is changed. For this reason, the obtained value of the refractive index is limited.

[0003] The present invention has been made in view of the above circumstances, and has a refractive index of 1.4 to 2.0 by a dry plating method.
An object of the present invention is to provide a method for controlling the refractive index of a dry plating film, which can reliably produce a thin film having an arbitrary refractive index in the range of 8.

[0004]

Means for Solving the Problems and Embodiments of the Invention As a result of intensive studies to achieve the above object, the present inventor has found that silicon carbide (SiC) is used as a target in a sputtering method, an evaporation source in a vapor deposition method, and the like. By changing the concentration of a reactive gas such as oxygen gas or nitrogen gas as a raw material source, SiC is mainly used and its carbon fraction is controlled in accordance with the concentration, so that 1.4 to 2.
The present inventors have found that a thin film having an arbitrary refractive index can be formed in a refractive index range of 8 (measurement temperature: 25 ° C.), and have accomplished the present invention.

That is, the present invention provides the following method for controlling the refractive index of a dry plating film. Claim 1: Silicon carbide having an arbitrary refractive index in the range of 1.4 to 2.8 on a substrate by subjecting a reactive gas concentration to dry plating with silicon carbide as a raw material source. A method for controlling the refractive index of a dry plating film, characterized by obtaining a thin film having the following characteristics. Claim 2: The method according to claim 1, wherein the reactive gas is a gas containing oxygen and / or a gas containing nitrogen. In a preferred embodiment, the reactive gas ratio [reactive gas flow rate / (reactive gas flow rate + inert gas flow rate) .times.100] is controlled in the range of 0 to 50%. In a preferred embodiment, the dry plating is sputtering. Claim 5: The density of silicon carbide as a raw material source is 2.9 g /
5. A silicon carbide sintered body which is obtained by sintering a mixture in which a silicon carbide powder and a non-metallic sintering aid are homogeneously mixed, each having a size of at least ³ cm ^3. Or the method of claim 1.

Hereinafter, the present invention will be described in more detail.

The method for controlling the refractive index of a dry plating film according to the present invention comprises dry-plating a substrate using silicon carbide as a raw material source.

In this case, as the dry plating method, various dry plating methods such as a sputtering method, a reactive evaporation method, and an ion plating method can be employed. Can be carried out by employing the usual method. Among these dry plating methods, a sputtering method can be preferably adopted. As the sputtering method, depending on the conductivity of the SiC target to be used, when the conductivity is low, a method such as high frequency sputtering or a high frequency magnetron sputtering is used. Is high, a method such as DC sputtering or DC magnetron sputtering is used. In particular, Si using a silicon carbide sintered body described later is used.
Since the C target material is conductive, DC sputtering and DC magnetron sputtering are preferred. In addition, as a base material, inorganic materials such as glass and ceramics,
An organic material such as a metal material, PMMA, or PET can be used.

The above-mentioned silicon carbide can be used as a target when the sputtering method is employed, and is used as an evaporation source in the case of the vapor deposition method and as an evaporation source in the case of the ion plating method.

Here, silicon carbide has a density of 2.
It is preferably 9 g / cm ³ or more and formed of a silicon carbide sintered body obtained by sintering a mixture in which silicon carbide powder and a nonmetallic sintering aid are homogeneously mixed. In this case, the total content of impurity elements contained in the silicon carbide sintered body is preferably 1 ppm or less. The non-metallic sintering aid is an organic compound that generates carbon by heating, such as coal tar pitch, phenolic resin, furan resin, epoxy resin, glucose, sucrose, cellulose, starch, and the like. Preferably, there is. Further, the nonmetallic sintering aid preferably covers the surface of the silicon carbide powder. The silicon carbide sintered body can be obtained by hot-pressing the mixture under a non-oxidizing atmosphere.

The silicon carbide powder used for producing the silicon carbide sintered body includes a silicon source containing at least one or more liquid silicon compounds and at least one or more liquid organic compounds that generate carbon by heating. After solidifying the mixture obtained by mixing the carbon source containing the compound and the polymerization or cross-linking catalyst to obtain a solid, and heating and carbonizing the obtained solid in a non-oxidizing atmosphere, It is preferably obtained by a manufacturing method including a firing step of firing in a non-oxidizing atmosphere.

In sintering the silicon carbide powder, the silicon carbide sintered body includes, as sintering aids, metals such as boron, aluminum and beryllium and metal-based sintering aids which are compounds thereof, carbon black, graphite, and the like. Since only non-metallic sintering aids are used without using a carbon-based sintering aid, etc., the purity of the sintered body is high, and there are few foreign substances at the crystal grain boundaries, and the thermal conductivity is excellent. In addition, to improve the durability of various types of jigs and tools, as well as thin films suitable for protective films and functional films of various electronic device parts, which are superior in contamination resistance and wear resistance compared to carbon materials as the intrinsic properties of silicon carbide. A useful surface-treated thin film or the like can be formed.

Therefore, in the present invention, it is preferable to use the above silicon carbide sintered body as a target or as an evaporation source.

In the present invention, the above-mentioned dry plating can be carried out in a reactive gas atmosphere while controlling (selecting appropriately) the concentration of the reactive gas. In this case, the reactive gas is not particularly limited except for the inert gas. However, oxygen gas containing oxygen, carbon monoxide gas, carbon dioxide gas, and the like, nitrogen gas containing nitrogen, nitrogen monoxide gas, and nitrogen dioxide gas are used. And ammonia gas. These gases may be used alone, in a mixture, or in a mixture of a gas containing oxygen and a gas containing nitrogen. When only these reactive gases are passed through the vacuum chamber, it depends on the size of the vacuum chamber or the like.
It is desirable to control the concentration in the range of １００100 ml / min. Further, the ratio of the reactive gas to the inert gas [reactive gas flow rate / (reactive gas flow rate + inert gas flow rate) × 100] is desirably in the range of 0 to 50%.

When the sputtering method is employed,
The input power varies depending on the size of the target.
The diameter can be selected in the range of 50 to 2000 W in the case of mmφ, and in the range of 0.5 to 30 W / cm ² in terms of the target input power density.

The thickness of the dry plating film is appropriately selected, and is usually 1 nm to 100 μm, especially 5 nm.
It can be formed to a thickness of nm to 10 μm.

When the reactive gas is oxygen gas, the dry plating film thus obtained is
_x O _y (x and y are arbitrary numbers) single film, SiC, Si
A mixed film of O, SiO ₂ and SiC _x O _y , and a single film of SiC _x N _y (x and y are arbitrary numbers) in the case of nitrogen gas;
Or _{SiC, Si 3 N 4, SiN} , becomes a mixture film of SiC _x N _y, depending on their reactive gas concentration, is carbon fraction control, refractive index 1.4 to 2.8, in particular 1.
S having an arbitrary refractive index in the refractive index range of 46 to 2.67
It is a thin film mainly composed of iC.

Such a thin film can be effectively used for various optical thin films, laminated optical filters, transparent wear-resistant films, hard coat films, half mirror films, and the like.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

Example 1 Sputtering was performed under the following conditions to form thin films having various refractive indices. Table 1 shows the results. Sputtering apparatus: DC magnetron sputtering apparatus Base material: Glass plate Target material: SiC Target size: 100 mmφ Supply gas: Argon gas 18 ml / min Oxygen gas Flow rate shown in Table 1 Pressure: 5 mTorr Supply power: 500 W Film formation time: 10 minutes Film thickness Measurement: Needle-type film thickness meter (manufactured by Taylor Bobson) Refractive index measurement: Ellipsometry (manufactured by JASCO) (measurement wavelength: 800 nm)

[0021]

[Table 1]

Example 2 Sputtering was performed in the same manner as in Example 1 except that the input power was changed to 1000 W, to form thin films having various refractive indexes shown in Table 2.

[0023]

[Table 2]

Example 3 Sputtering was carried out in the same manner as in Example 1 except that nitrogen gas was used as the reactive gas instead of oxygen gas and the input power was 1000 W. Having a thin film.

[0025]

[Table 3]

Example 4 Reactive vapor deposition was performed under the following conditions to form thin films having various refractive indices. Table 4 shows the results
Shown in Evaporation apparatus: Electron beam evaporation apparatus Base material: Glass plate Evaporation source: SiC Supply gas: Oxygen gas 10 ml / min Ion source input power: 500 W Pressure: 3 × 10 ⁻⁵ Torr Film formation time: 1 minute

[0027]

[Table 4]

From the results of the above examples, it was confirmed that thin films having various refractive indices can be formed by controlling the concentration (flow rate) of the reactive gas (oxygen gas or nitrogen).

[0029]

According to the present invention, the refractive index is 1.4 to 2.8.
Thus, a laminated film having an arbitrary change in the refractive index along the thickness direction can be reliably formed.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H01L 21/203 G02B 1/10 Z F Term (Reference) 2H048 GA03 2K009 AA15 BB02 CC01 DD04 4K029 BA56 BC07 CA06 DC05 DC09 EA00 EA04 5F103 AA01 AA02 AA08 BB22 BB56 DD30 HH04 HH05 NN06 NN10

Claims (5)

[Claims] 1. A dry plating method using silicon carbide as a raw material source while controlling the concentration of a reactive gas to obtain silicon carbide having an arbitrary refractive index in the range of 1.4 to 2.8 on a substrate. A method for controlling a refractive index of a dry plating film, which comprises obtaining a thin film as a main component. 2. The method according to claim 1, wherein the reactive gas is a gas containing oxygen and / or a gas containing nitrogen. 3. The reactive gas ratio [reactive gas flow rate / (reactive gas flow rate + inert gas flow rate) × 100] is set to 0 to 50.
3. The method according to claim 1, wherein the control is performed in the range of%. 4. The method according to claim 1, wherein the dry plating is sputtering. 5. A silicon carbide having a density of 2.9 as a raw material source.
g / cm ³ or more, and a silicon carbide sintered body obtained by sintering a mixture in which silicon carbide powder and a nonmetallic sintering aid are homogeneously mixed.
The method according to claim 1.