JP5426137B2 - Tantalum oxide vapor deposition material, production method thereof, and production method of tantalum oxide vapor deposition film - Google Patents

Description

  The present invention relates to a tantalum oxide vapor deposition material used for forming a vapor deposition film of tantalum oxide on a substrate by vacuum vapor deposition, a method for producing the same, and a tantalum oxide vapor deposition film using the tantalum oxide vapor deposition material as a vapor deposition material for vacuum vapor deposition. It relates to a manufacturing method.

As a vapor deposition material for forming a high refractive index layer, tantalum oxide (Ta ₂ O ₅ ) (refractive index: n = 2.1), zirconium oxide (ZrO ₂ ) (refractive index: n = 2.2), titanium oxide (TiO ₂ ) (refractive index: n = 2.4), niobium oxide (Nb ₂ O ₅ ) (refractive index: n = 2.1), and the like are used.

  Especially, the vapor deposition film formed using tantalum oxide as a vapor deposition material has a high refractive index and high hardness. For example, it is used as a high refractive material for multilayer films such as filters, dichroic mirrors, and plastic lenses. As an ordinary tantalum pentoxide vapor deposition material, pellets or targets formed by pressing a tantalum pentoxide powder into a sintered body are used.

  The tantalum oxide vapor deposition film is usually deposited on the substrate by vacuum vapor deposition. In this method, the container containing the substrate to be coated and the deposition material is first placed in a suitable vacuum deposition apparatus, then the apparatus is evacuated and evacuated, heated and / or electron beam bombarded. Thus, the vapor deposition material is evaporated and deposited on the substrate surface in the form of a thin film.

  A tantalum oxide vapor deposition material for forming such a tantalum oxide vapor deposition film is disclosed in, for example, Japanese Patent Laid-Open Nos. 4-325669 (Patent Document 1) and 2006-111974 (Patent Document 2).

JP-A-4-325669 (Claims) JP 2006-111974 A (Claims)

  However, in the vapor deposition materials of Patent Documents 1 and 2 described above, (1) deoxygenation occurs during vacuum deposition, and the degree of vacuum in the vacuum deposition apparatus is reduced. Therefore, there is a time loss for stabilizing the degree of vacuum. (2) Splash occurred during vacuum deposition, and stable film formation was difficult, resulting in problems such as a decrease in yield and non-uniform film thickness.

  Therefore, the subject of this invention is providing the manufacturing method of the tantalum oxide vapor deposition material with which the degree of vacuum of a vacuum vapor deposition apparatus cannot fall easily in the case of vacuum vapor deposition, and there is little splash amount.

In such a situation, the present inventor has intensively studied to solve the problems in the prior art, and as a result, Ta ₂ O ₅ is baked at 1200 ° C. or higher as a deposition material, and then an electron beam in a vacuum atmosphere. By using a vapor deposition material obtained by melting by a melting method, it was found that the degree of vacuum is difficult to drop during vacuum deposition and the amount of splash is small, and the present invention has been completed.

That is, the present invention provides a tantalum oxide vapor deposition material obtained by firing Ta ₂ O ₅ at 1200 ° C. or higher, then melting it by an electron beam melting method in a vacuum atmosphere , and cooling it. .

The present invention also includes an I step of firing Ta ₂ O ₅ at 1200 ° C. or higher,
After dissolving by electron beam melting method under vacuum sintered body obtained in step I, and II to obtain a tantalum oxide evaporation material by cooling,
The manufacturing method of the tantalum oxide vapor deposition material characterized by having this.

  Moreover, this invention provides the manufacturing method of the tantalum oxide vapor deposition film characterized by performing vacuum vapor deposition using the said tantalum oxide vapor deposition material, and obtaining a tantalum oxide vapor deposition film.

  According to the present invention, it is possible to provide a tantalum oxide vapor deposition material and a method for manufacturing the same, in which the degree of vacuum in the vacuum vapor deposition apparatus is difficult to drop and the amount of splash is small during vacuum vapor deposition.

The tantalum oxide vapor deposition material of the present invention is obtained by firing Ta ₂ O ₅ at 1200 ° C. or higher and then melting it by an electron beam melting method in a vacuum atmosphere. It is a vapor deposition material used for forming on a substrate.

Tantalum oxide evaporation material of the present invention is preferably one mainly composed of mixed phases of _Ta 2 _{O 5} phase and Ta ₂ O phase, mixed phase of _Ta 2 _{O 5} phase and Ta ₂ O phase is particularly preferred. The tantalum oxide vapor deposition material of the present invention may contain other compounds or impurities as long as the effects of the present invention are not impaired, but the optical properties of the vapor deposition film, such as refractive index, transmittance, etc. In view of the influence on the tantalum oxide, it is desirable that the tantalum oxide vapor deposition material of the present invention has high purity.

  As the tantalum oxide vapor deposition material of the present invention, those produced by the method for producing a tantalum oxide vapor deposition material of the present invention shown below, the vacuum degree in the vacuum vapor deposition apparatus is difficult to drop during vacuum deposition, and splash It is preferable in that the effect that the amount is small increases.

The method for producing a tantalum oxide vapor deposition material according to the present invention includes an I step in which Ta ₂ O ₅ is fired at 1200 ° C. or higher, and a sintered body obtained in the I step is melted and oxidized by an electron beam melting method in a vacuum atmosphere. II process which obtains a tantalum vapor deposition material.

Ta ₂ O ₅ used in step I is formed by forming powdered Ta ₂ O ₅ or powdered Ta ₂ O ₅ into particles, pellets, or the like. The powdery Ta ₂ O _{5 as} a raw material is preferably as high as possible in purity, and commercially available products can be used as appropriate. By using Ta ₂ O ₅ as a molded body, a Ta ₂ O ₅ sintered body having a high density can be obtained after firing. As a method of forming the powdered Ta ₂ O ₅ , a known forming method such as a normal hydraulic or mechanical press device, injection molding device, extrusion molding device or the like is used. An appropriate binder component may be added as necessary in order to improve galling prevention and mold releasability of the mold or to improve the bondability between the raw materials Ta ₂ O ₅ .

In step I, Ta ₂ O ₅ is transferred to a heating furnace and baked. The firing atmosphere is not particularly limited, and for example, the firing is performed in a vacuum, under an inert gas atmosphere, under a reducing atmosphere, in the air, or in an oxidizing atmosphere. Among these, it is preferable to perform the sintering in a vacuum atmosphere from the viewpoint that the dissolution rate of the electron beam melting in the subsequent step can be increased. In addition, you may perform baking by a pressurized state.

The firing temperature is 1200 ° C. or higher. By setting the temperature to 1200 ° C. or higher, the density of the sintered Ta ₂ O ₅ sintered body becomes 4.4 g / cm ³ or higher. The density of the Ta ₂ O ₅ sintered body can be determined by measuring its volume and mass. The volume is calculated based on the difference between the water level when the Ta ₂ O ₅ sintered body is placed in the container and the Ta ₂ O ₅ sintered body is placed in the water, and the dimensions of the sintered body are measured. This can be measured. Since the true specific gravity of Ta ₂ O ₅ is 8.7 g / cm ³ , the relative density is 50% or more. Therefore, in the electron beam method melting in the next step, it is possible to increase the processing amount for one melting. In addition, the Ta ₂ O ₅ sintered body has good solubility in electron beam melting, and hardly melts away. Further, by baking the Ta ₂ O ₅ formed body, it is possible to remove adsorbed gases Ta ₂ O ₅ formed body contains, can reduce the dissolution process time of the electron beam melting method, also the arc of the electron beam Stabilize. It is preferable that the fired Ta ₂ O ₅ sintered body is quickly vacuum-packed with a polyethylene sheet or the like in terms of preventing adsorption of water or the like after firing.

In step II, the sintered body obtained in step I is irradiated with an electron beam in a vacuum atmosphere to dissolve the sintered body, and Ta ₂ O ₅ after firing by an electron beam melting method (EB melting method). The sintered body is melted. Note that the vacuum atmosphere refers to a degree of vacuum of 1.33 × 10 ⁻² Pa (1 × 10 ⁻⁴ torr) or less.

In the step II, the method for melting the Ta ₂ O ₅ sintered body by the electron beam melting method is not particularly limited, and the electron beam melting method usually used for melting metal can be used. By using the sintered Ta ₂ O ₅ sintered body, the melting rate in electron beam melting can be increased, the tantalum oxide deposition material of the present invention can be produced in a short time, and the tantalum oxide deposition material can be produced. Can be improved. Further, raw material Ta ₂ O ₅ sintered body, when the arc melting, in order to prevent the Ta ₂ O ₅ sintered body is scattered, those formed into granules or pellets or the like.

In step II, the sintered Ta ₂ O ₅ sintered body is melted by an electron beam melting method in a vacuum atmosphere, and then cooled in a furnace in an inert gas atmosphere to obtain a tantalum oxide vapor deposition material.

  The method for producing a tantalum oxide vapor deposition material film of the present invention uses a tantalum oxide vapor deposition material obtained by the production method of the present invention as a vapor deposition material, and deposits tantalum oxide by vacuum vapor deposition. It is a manufacturing method of the tantalum oxide vapor deposition film which forms a film.

  In the method for producing a tantalum oxide vapor deposition material film of the present invention, the substrate on which the vapor deposition film is formed is not particularly limited, and a substrate usually used for vapor deposition of tantalum oxide can be mentioned.

In the method for producing a tantalum oxide vapor deposition material film of the present invention, the method for performing vacuum vapor deposition is not particularly limited, and a vacuum vapor deposition method for forming a tantalum oxide vapor deposition film can be usually used. A method of heating the vapor deposition material under a vacuum atmosphere, a method of irradiating the vapor deposition material filled in, for example, a water-cooled copper crucible under a vacuum atmosphere, and an electron beam applied to the vapor deposition material while heating the vapor deposition material under a vacuum atmosphere. And the like. In addition, the vacuum atmosphere at the time of performing this vacuum vapor deposition means a vacuum degree of 1.33 × 10 ⁻² Pa (1 × 10 ⁻⁴ torr) or less.

  In the method for producing a tantalum oxide vapor deposition film of the present invention, the apparatus for performing vacuum vapor deposition is not particularly limited, and an apparatus usually used for vacuum vapor deposition of tantalum oxide can be used.

In the method for producing a tantalum oxide vapor deposition film of the present invention, since the Ta ₂ O ₅ molded body is fired before the EB melting method, (i) the solubility in the EB melting apparatus is good and it dissolves in a short time. (Ii) it is difficult to generate unmelted residue, and (ii) since the density is high, the amount of charge per one time to the EB melting apparatus can be increased, which is economical. (Iii) The uniformity is improved, the yield is improved by vapor deposition, and the vacuum is not easily deteriorated in the vapor deposition apparatus, so that the processing time can be shortened, and (iv) the occurrence of splash is small, so that Damage is reduced, (v) a relatively stable deposition rate (speed) can be maintained, and (vi) Ta ₂ O is present, so the use of an ion assist method in which oxygen is introduced using an ion gun or the like is used. It has features such as being applicable preferably

  And the tantalum oxide vapor deposition film is formed in this base material by performing the manufacturing method of the tantalum oxide vapor deposition film of this invention. The tantalum oxide vapor-deposited film thus obtained is a vapor-deposited film having high uniformity such as film thickness and having excellent optical characteristics.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

(Manufacture of vapor deposition material)
Ta ₂ O ₅ powder (purity 99.9% or more) having an average particle size of 10 μm or less was formed into a cylindrical molded body having a diameter of 60 mm and a thickness of 20 mm using a press molding apparatus. Next, this compact was put in a heating furnace and baked in a vacuum atmosphere (vacuum degree: 1.33 Pa (1 × 10 ⁻² Torr) for 1 hour at 1200 ° C. Thereafter, the atmosphere in the furnace was kept as it was and the furnace was cooled. Thereafter, the sintered body after firing was vacuum-packed and stored with an aluminum-deposited polyethylene sheet (process I.) As a result of measurement by powder X-ray diffraction, sintered Ta ₂ O ₅ sintered body was _Ta 2 _{O 5} (tetragonal). Further, from the volume and weight of the _Ta 2 _{O 5} sintered body, the result of measuring the density, calcined _Ta 2 _{O 5} sintered body, 4.6 g / Cm ³ and the relative density was 52%.

Next, the sintered Ta ₂ O ₅ was set in a copper water-cooled crucible, and then evacuation was performed until the degree of vacuum in the furnace was on the order of 10 ⁻³ Pa. Next, the sintered Ta ₂ O ₅ was melted by an electron beam melting method to obtain a vapor deposition material. At this time, the electron beam was gradually irradiated from one end portion of the sintered Ta ₂ O _{5 to} the other end portion and dissolved (step II).

At that time, the dissolution rate of the entire molded body, the presence or absence of vacuum deterioration, and the state of arcing were evaluated. The results are shown in Table 1. The melting rate of the entire compact is the mass (kg) of the sample set in the electron beam melting device divided by the melting time (hour). In the arcing state, the electron beam is stably irradiated continuously. It is evaluated whether it can be done. Moreover, the obtained vapor deposition material was measured by the powder X-ray diffraction method under the following measurement conditions. As a result, the vapor deposition material was a mixed phase of Ta ₂ O ₅ (tetragonal) and Ta ₂ O (cubic).

<X-ray diffraction measurement conditions>
Diffraction device RAD-1C (manufactured by Rigaku Corporation)
X-ray tube Cu
Tube voltage / tube current 40kV, 30mA
Slit DS-SS: 1 degree, RS: 0.15mm
Monochromator Graphite Measurement interval 0.002 degree Counting method Constant clock method

(Manufacture of evaporated film)
Next, the vapor deposition material was pulverized, and the pulverized vapor deposition material was placed in a vacuum vapor deposition apparatus. Next, 12 g of the vapor-deposited vapor deposition material was put into a water-cooled copper crucible, and then the pressure was reduced to a vacuum degree of 1.33 × 10 ⁻³ Pa (10 ⁻⁵ torr). Thereafter, an electron was output at a current of 400 mA and a voltage of 6 kV. By irradiating the deposition material with an electron beam with a gun (manufactured by JEOL Ltd.), the base was prepared by melting in a liner, and vacuum deposition was performed on a quartz glass substrate to form a deposited film. The state of occurrence of splash during vacuum deposition and the deterioration of the vacuum state were evaluated by pressure fluctuations during melting. The results are shown in Table 2.

  In addition, the occurrence state of splash was evaluated as follows. For the sintered body (Comparative Example 2), “2: Splash generation is high”, “5: Splash generation is low”, “4: Splash generation is low”, “3: Splash generation is high”, “2: Splash generation is low”. Relative evaluations were made, such as “Many occurrences of splash” and “1: Many occurrences of splash”. The deterioration of the degree of vacuum was evaluated relative to the sintered body (Comparative Example 2) as the three stages “3: small pressure fluctuation”, “2: standard”, “1: large pressure fluctuation”.

(Manufacture of vapor deposition material)
The same procedure as in Example 1 was performed except that an air atmosphere was used instead of the vacuum atmosphere in step I. In addition, as a result of measuring the density of the Ta ₂ O ₅ sintered body obtained in the step I, it was 4.4 g / cm ³ and the relative density was 51%. As a result of the evaporation material obtained in step II was determined by powder X-ray diffraction method, it was Ta 2 _O 5 _(tetragonal) and Ta 2 _{O (cubic).}

(Manufacture of evaporated film)
It carried out by the method similar to Example 1 using the vapor deposition material obtained as mentioned above. The results are shown in Tables 1 and 2.

Comparative Example 1
(Manufacture of vapor deposition material)
Ta ₂ O ₅ powder (purity 99.9% or more) having an average particle size of 10 μm or less was formed into a cylindrical molded body having a diameter of 60 mm and a thickness of 20 mm using a press molding apparatus. Next, 100 g of this compact was filled in a copper water-cooled hearth of a non-consumable arc furnace, and the inside of the furnace was completely replaced with argon gas. A voltage of 55 V was applied for arc melting for 20 minutes, and then the atmosphere in the furnace was kept as it was and the furnace was cooled to obtain a vapor deposition material. As a result of measurement by a powder X-ray diffraction method, the vapor deposition material was Ta ₂ O ₅ (tetragonal crystal).

(Manufacture of evaporated film)
It carried out by the method similar to Example 1 using the vapor deposition material obtained as mentioned above. The results are shown in Tables 1 and 2.

Comparative Example 2
(Vapor deposition material)
A commercially available Ta ₂ O ₅ sintered body was used as a vapor deposition material. As a result of measurement by a powder X-ray diffraction method, the commercially available Ta ₂ O ₅ sintered body was Ta ₂ O ₅ (tetragonal crystal).

(Manufacture of evaporated film)
Using a commercially available Ta ₂ O ₅ sintered body was obtained in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Comparative Example 3
(Manufacture of vapor deposition material)
Instead of following _Ta 2 _{O 5} powder having an average particle size of 10 [mu] m (purity: 99.9% or higher), it has an average particle diameter of 1μm or less of _Ta 2 _{O 5} powder (purity 99.9%), 1 1200 ° C. The same procedure as in Example 1 was performed except that the firing was not performed in place of the firing of time. In addition, as a result of measuring the density of the obtained Ta ₂ O ₅ sintered body, it was 2.0 g / cm ³ and the relative density was 23%.

(Manufacture of evaporated film)
It carried out by the method similar to Example 1 using the vapor deposition material obtained as mentioned above. The results are shown in Tables 1 and 2.

Comparative Example 4
(Manufacture of vapor deposition material)
Ta ₂ O ₅ powder (purity 99.9% or more) having an average particle size of 10 μm or less was formed into a cylindrical molded body having a diameter of 60 mm and a thickness of 20 mm using a press molding apparatus. The molded body of Ta ₂ O ₅ was subjected to heat treatment (adsorption gas removal treatment) in a vacuum heating furnace at a degree of vacuum of 1 × 10 ⁻² Torr, a treatment temperature of 300 ° C., and a treatment time of 1 hour. Thereafter, the heat-treated molded body was vacuum-packed with an aluminum-deposited polyethylene sheet and stored. In addition, the density of the molded object after an adsorption gas removal process was 2.6 g / cm < ³ >, and the relative density was 29%. Next, electron beam melting was performed in the same manner as in Example 1 to obtain a vapor deposition material.

(Manufacture of evaporated film)
It carried out by the method similar to Example 1 using the vapor deposition material obtained as mentioned above. The results are shown in Tables 1 and 2.

Comparative Example 5
(Manufacture of vapor deposition material)
It carried out similarly to the comparative example 4 except having replaced with process temperature 300 degreeC, and having set process temperature 1000 degreeC. In addition, the density of the molded object after an adsorption gas removal process was 2.8 g / cm < ³ >, and the relative density was 32%. Next, electron beam melting was performed in the same manner as in Example 1 to obtain a vapor deposition material.

(Manufacture of evaporated film)
It carried out by the method similar to Example 1 using the vapor deposition material obtained as mentioned above. The results are shown in Tables 1 and 2.

Evaluation of the splash amount: “5: Splash is not generated”, “4: Splash is low”, “3: Splash is slightly high”, “2: Splash is high”, “1: Splash is high. "
Deterioration of vacuum degree: “3: Small pressure fluctuation”, “2: Same as standard”, “1: Large pressure fluctuation”

  By the manufacturing method of the vapor deposition material of Examples 1-2, the solubility in an EB melt | dissolution apparatus is good, and it can melt | dissolve in a short time. Moreover, the vapor deposition material obtained by the manufacturing method of the vapor deposition material of Examples 1-2 has little splash amount at the time of vapor deposition, and can maintain a high degree of vacuum.

  According to the present invention, since the solubility in the EB melting apparatus is good and the melting can be performed in a short time, an industrially advantageous vapor deposition material can be manufactured. Further, since the degree of vacuum of the vacuum deposition apparatus is difficult to drop and the amount of splash can be reduced during vacuum deposition, a material in which a tantalum oxide deposition film is deposited on a base material can be produced industrially advantageously.

Claims (3)

A tantalum oxide vapor-deposited material obtained by firing Ta ₂ O ₅ at 1200 ° C. or higher, and then melting it by an electron beam melting method in a vacuum atmosphere, followed by cooling . I step of firing Ta ₂ O ₅ at 1200 ° C. or higher;
After dissolving by electron beam melting method under vacuum sintered body obtained in step I, and II to obtain a tantalum oxide evaporation material by cooling,
The manufacturing method of the tantalum oxide vapor deposition material characterized by having.   A method for producing a tantalum oxide vapor deposition film, wherein the tantalum oxide vapor deposition material according to claim 1 is vacuum-deposited to obtain a tantalum oxide vapor deposition film.