JP2007332407A - Vapor deposition material for optical thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for vapor deposition or a material for ion-plating capable of obtaining a transparent conductive film of high density, high transparency and low resistance through the high-speed film deposition without any fluctuation in the composition during a sintering process or without generation of any nodule, deformation of a target, or damages such as cracks during the film deposition. <P>SOLUTION: A vapor deposition material for an optical thin film consists of a compound or a mixture of indium oxide (In<SB>2</SB>O<SB>3</SB>), tungsten oxide (WO<SB>3</SB>), and magnesium oxide (MgO). Alternatively, the vapor deposition material for the optical thin film consists of a compound or a mixture of indium oxide (In<SB>2</SB>O<SB>3</SB>), tungsten oxide (WO<SB>3</SB>), and magnesium oxide (MgO), and is formed of a sintered body thereof sintered in a high-temperature oxygen atmosphere or in a high-temperature air atmosphere. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vapor deposition material for an optical thin film for vapor deposition or ion plating.

Indium tin oxide (ITO) films and indium zinc oxide (IZO) films are used as transparent conductive films excellent in liquid crystal displays, color filters, thin film transistors, solar cells, and the like. ITO film an ITO sintered body consisting of tin oxide and indium oxide _{(In 2 O 3) (SnO} 2) and the evaporation source or the target, the IZO film of indium oxide (In ₂ O ₃₎₎ and zinc oxide (ZnO) This IZO sintered body is used as an evaporation source or target. A film is formed by vacuum deposition or ion plating using these sintered body materials.

  Since these sintered body materials are required to have a high density in any film forming method, sintering in a high temperature atmosphere is indispensable. In the high-density sintered body, there is a problem that cracking of the material is likely to occur during the manufacturing process and the film formation as compared with the low-density sintered body. Furthermore, with these sintered materials, needle deposition called nodules occurs in the erosion part as the film formation progresses, which causes a problem of local deterioration in film formation efficiency and abnormal film discharge. It has become.

Various techniques have been developed to solve such problems. For example, in the ITO sintered body, the generation of cracks during the manufacturing process is prevented by adding magnesium oxide (MgO) as the third material (see Patent Document 1). Further, for example, in an IZO sintered body, generation of nodules is prevented by adding magnesium oxide (MgO) as a third substance (see Patent Document 2).
JP 2003-55759 A JP 2005-307269 A

  In recent years, an indium / tungsten oxide film having transparency in a wider wavelength region has attracted attention as a transparent conductive film particularly suitable for solar cells.

The indium / tungsten oxide film is formed by vacuum deposition or ion plating using a sintered body made of indium oxide (In ₂ O ₃ ) and tungsten oxide (WO ₃ ) as an evaporation source or target.

Since this sintered body material is required to have a high density in any film forming method, sintering in a high temperature atmosphere is indispensable. In the case of a sintered body made of indium oxide (In ₂ O ₃ ) and tungsten oxide (WO ₃ ), since the evaporation temperature of tungsten oxide is low (sublimation starts at about 850 ° C in the case of a single substance), sintering is performed at high temperature. There is a problem that the tungsten oxide concentration becomes smaller than before, and a sintered body having a target composition cannot be obtained.

  However, Patent Documents 1 and 2 do not disclose a technique that suppresses evaporation of a low-temperature evaporating substance such as tungsten oxide and enables high-temperature firing.

In addition, even in high-density sintered bodies made of indium oxide (In ₂ O ₃ ) and tungsten oxide (WO ₃ ), material cracking during the manufacturing process and film formation, and nodules during film formation occur. Although it is a problem, unlike the ITO sintered body and the IZO sintered body, the addition of the third substance has not been studied so far.

The present invention has been made in order to solve the above-mentioned problems, and the object thereof is to change the composition of a sintered body made of indium oxide (In ₂ O ₃ ) and tungsten oxide (WO ₃ ) even by high-temperature firing. It is an object of the present invention to provide a vapor deposition material for an optical thin film for vapor deposition or ion plating that can provide stable film characteristics. Another object of the present invention is to provide a vapor deposition material for an optical thin film for vapor deposition or ion plating, in which no cracking of the material occurs even in a high-density sintered body and no nodules are generated during film formation. Is to provide.

Therefore, in the present invention, in the sintered body made of indium oxide (In ₂ O ₃ ) and tungsten oxide (WO ₃ ), the improvement of the material by adding the third substance is studied, and the addition of magnesium oxide (MgO) makes this material unique. It was found that the low temperature evaporation of tungsten oxide, which is a problem of the above, can be suppressed, and a high density material can be obtained by high temperature sintering. It was also found that the high-density material obtained by this method does not cause cracking of the material and suppresses the generation of nodules.

That is, the present invention is a vapor deposition material for an optical thin film characterized by being a compound or a mixture of indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ), and magnesium oxide (MgO).

Further, the present invention is a compound or mixture comprising indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ) and magnesium oxide (MgO) as main components, and the Mg content is 0.05 wt% to 1.00 wt%. A vapor deposition material for an optical thin film characterized by having the following composition.

The present invention also relates to a compound or mixture of indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ), and magnesium oxide (MgO), which is sintered in a high-temperature oxygen atmosphere or a high-temperature air atmosphere. It is a vapor deposition material for optical thin films characterized by being a body.

  The vapor deposition material for optical thin film of the present invention does not change its composition even in a high temperature atmosphere, can be densified by high temperature firing, does not generate cracks due to thermal shock during electron beam irradiation during deposition, and forms a film. Occasionally, nodules are hardly generated, so that no defects occur in the film.

  Embodiments of the present invention will be described below.

The vapor deposition material for optical thin film of the present invention specifically mixes indium oxide (In ₂ O ₃ ) powder and tungsten oxide (WO ₃ ) powder and magnesium oxide (MgO) powder, and after molding this mixture, Indium oxide (In ₂ O ₃ ) and tungsten oxide (WO ₃ ) obtained by sintering the sintered body, or by pulverizing this sintered body into a powder, further molding and firing the powder And magnesium oxide (MgO).

The indium oxide (In ₂ O ₃ ) powder, tungsten oxide (WO ₃ ) powder and magnesium oxide (MgO) powder used in the present invention, and a pulverized powder of a compound or mixture obtained by molding and firing are not particularly limited, Any of them can be used, but a powder having an appropriate particle size is desirable so that it can be easily mixed and sintered. Their average particle size is preferably 1 mm or less.

  Thereby, since the void | hole between particle | grains becomes an optimal value, since a shaping | molding density is raised and also sintering by baking is promoted, it becomes possible to obtain a high-density sintered compact.

  Firing is performed in a high-temperature oxygen atmosphere or a high-temperature air atmosphere, preferably 1400 ° C. or higher, and more preferably 1500 ° C. or higher. Thereby, sintering of the powder raw material is promoted, and a high-density sintered body can be obtained.

  The Mg content is preferably 0.05 to 1.00 wt%.

If the addition amount is less than this, a sufficient addition effect cannot be obtained, and tungsten oxide (WO ₃ ) evaporates during high-temperature firing, resulting in a change in composition. Moreover, it is because the density of a sintered compact will fall when it adds more than this.

  Examples of the present invention will be described below.

Example 1
95.417 wt% indium oxide (In ₂ O ₃ ) powder by weight ratio, 4.5 wt% tungsten oxide (WO ₃ ) powder by weight ratio, and 0.083 wt% magnesium oxide (MgO) powder (by Mg content) 0.05wt%) was mixed, powdered using a molding die with a diameter of 40mm at a press pressure of 78.4MPa (800kgf / cm ² ), and then sintered at 1500 ° C for 5 hours in an air atmosphere to obtain a density of 3.89 A tablet with a deposition material of g / cm ³ was obtained.

When this tablet was subjected to X-ray fluorescence analysis, no change was observed in the concentration of tungsten oxide (WO ₃ ).

(Example 2)
93.84 wt% indium oxide (In ₂ O ₃ ) powder by weight ratio, 4.5 wt% tungsten oxide (WO ₃ ) powder by weight ratio, and 1.66 wt% magnesium oxide (MgO) powder (by Mg content) 1.00wt%) was mixed and powder-molded at a press pressure of 78.4MPa (800kgf / cm ² ) using a mold with a diameter of 40mm, and then sintered at 1500 ° C for 5 hours in an air atmosphere to obtain a density of 3.81 to give tablets evaporation materials of g / cm ^3.

When this tablet was subjected to X-ray fluorescence analysis, no change was observed in the concentration of tungsten oxide (WO ₃ ).

(Example 3)
95.458 wt% indium oxide (In ₂ O ₃ ) powder by weight ratio, 4.5 wt% tungsten oxide (WO ₃ ) powder by weight ratio, and 0.042 wt% magnesium oxide (MgO) powder (by Mg content) 0.025wt%) was mixed, powdered with a pressing mold of 78.4MPa (800kgf / cm ² ) using a molding die with a diameter of 40mm, and then sintered at 1500 ° C for 5 hours in an air atmosphere to obtain a density of 3.92 A tablet with a deposition material of g / cm ³ was obtained.

When this tablet was subjected to X-ray fluorescence analysis, a decrease in the concentration of tungsten oxide (WO ₃ ) was observed.

Example 4
In 92.18Wt% indium oxide (In ₂ O ₃₎ powder and ratio _of tungsten oxide (WO ₃₎ of 4.5 wt% in a weight ratio powder and 3.32Wt% magnesium oxide (MgO) powder at a ratio of (Mg content ratio by weight 2.00wt%), powder-molded using a molding die with a diameter of 40mm at a press pressure of 78.4MPa (800kgf / cm ² ), and then sintered at 1500 ° C for 5 hours in an air atmosphere to deposit the material. Pills were obtained. The density of this tablet was 3.68 g / cm ³ , which was smaller than those of Examples 1, 2, and ³ .

When this tablet was subjected to X-ray fluorescence analysis, no change was observed in the concentration of tungsten oxide (WO ₃ ).

(Example 5)
Mixing 95.38 wt% indium oxide (In ₂ O ₃ ) powder by weight, 4.5 wt% tungsten oxide (WO ₃ ) powder by weight, and 0.12 wt% magnesium oxide (MgO) powder by weight, The powder was molded using a 40 mm mold at a press pressure of 78.4 MPa (800 kgf / cm ² ) and then sintered at 1500 ° C. for 5 hours in an air atmosphere to obtain a tablet.

This sintered body was pulverized into fine particles having a diameter of 1.00 mm or less to prepare adjusted powder. Furthermore, this adjusted powder was mixed to 70 wt% and indium oxide (In ₂ O ₃ ) powder to 30 wt% (Mg content of the whole material was 0.05 wt%), and this mixed powder was molded into a mold with a diameter of 25 mm. Was used to form a powder at a press pressure of 49 MPa (500 kgf / cm ² ) and then sintered at 1400 ° C. for 5 hours in an air atmosphere to obtain a tablet as a vapor deposition material.

The density of this tablet was 4.05 g / cm ³ .

When this tablet was subjected to X-ray fluorescence analysis, no change was observed in the concentration of tungsten oxide (WO ₃ ).

Next, this tablet is loaded into an electron gun placed in a vapor deposition device, evacuated to a vacuum of 1 × 10 ⁻³ Pa, and O ₂ gas is brought to a pressure of 2 × 10 ⁻² Pa at a substrate temperature of 300 ° C. The film was introduced into the quartz substrate at a film formation rate of 0.7 mm / sec until the film thickness reached 200 nm. This tablet could be easily deposited without generation of nodules and cracks.

(Example 6)
93.13Wt% of indium oxide (In ₂ O ₃₎ 4.5wt% of tungsten oxide powder in a weight ratio (WO ₃₎ powder in a weight ratio mixture of 2.37Wt% of magnesium oxide (MgO) powder at a ratio of diameter Powder molding was performed at a press pressure of 78.4 MPa (800 kgf / cm ² ) using a 40 mm molding die, followed by sintering at 1500 ° C. for 5 hours in an air atmosphere to obtain a vapor deposition material tablet.

This sintered body was pulverized into fine particles having a diameter of 1.00 mm or less to prepare adjusted powder. Furthermore, this adjusted powder was mixed so that 70 wt% and indium oxide (In ₂ O ₃ ) powder would be 30 wt% (Mg content as a whole material was 1.00 wt%), and this mixed powder was molded into a mold with a diameter of 25 mm. Was used to form a powder at a press pressure of 49 MPa (500 kgf / cm ² ) and then sintered at 1400 ° C. for 5 hours in an air atmosphere to obtain a tablet as a vapor deposition material.

The density of this tablet was 4.42 g / cm ³ .

When this tablet was subjected to X-ray fluorescence analysis, no change was observed in the concentration of tungsten oxide (WO ₃ ).

Next, this tablet is loaded into an electron gun placed in a vapor deposition device, evacuated to a vacuum of 1 × 10 ⁻³ Pa, and O ₂ gas is brought to a pressure of 2 × 10 ⁻² Pa at a substrate temperature of 300 ° C. The film was introduced into the quartz substrate at a film formation rate of 0.7 mm / sec until the film thickness reached 200 nm. This tablet could be easily deposited without generation of nodules and cracks.

(Example 7)
95.443Wt% of indium oxide (In ₂ O ₃₎ 4.5wt% of tungsten oxide powder in a weight ratio (WO ₃₎ powder in a weight ratio mixture of 0.057Wt% magnesium oxide (MgO) powder at a ratio of diameter Powder molding was performed using a 40 mm molding die at a pressing pressure of 49 MPa (500 kgf / cm ² ), and then sintered in an air atmosphere at 1500 ° C. for 5 hours to obtain a vapor deposition material tablet.

This sintered body was pulverized into fine particles having a diameter of 1.00 mm or less to prepare adjusted powder. Furthermore, this adjusted powder was mixed so that 70 wt% and indium oxide (In ₂ O ₃ ) powder would be 30 wt% (Mg content as a whole material was 0.025 wt%), and this mixed powder was molded into a mold with a diameter of 25 mm. Was used to form a powder at a press pressure of 49 MPa (500 kgf / cm ² ) and then sintered at 1400 ° C. for 5 hours in an air atmosphere to obtain a tablet as a vapor deposition material.

The density of this tablet was 4.01 g / cm ³ .

When this tablet was subjected to X-ray fluorescence analysis, a decrease in the concentration of tungsten oxide (WO ₃ ) was observed.

Next, this tablet is loaded into an electron gun placed in a vapor deposition device, evacuated to a vacuum of 1 × 10 ⁻³ Pa, and O ₂ gas is brought to a pressure of 2 × 10 ⁻² Pa at a substrate temperature of 300 ° C. However, the tablet was cracked and could not be deposited.

(Example 8)
90.76 wt% indium oxide (In ₂ O ₃ ) powder by weight ratio, 4.5 wt% tungsten oxide (WO ₃ ) powder by weight ratio, and 4.74 wt% magnesium oxide (MgO) powder by weight ratio are mixed, and the diameter after powder molding at a press pressure of 78.4MPa (800kgf / cm ²⁾ using a mold of 40 mm, to give tablets deposition material for 5 hours and sintered at 1500 ° C. in air atmosphere.

This sintered body was pulverized into fine particles having a diameter of 1.00 mm or less to prepare adjusted powder. Furthermore 70 wt% and indium oxide this adjustment powder (In ₂ O ₃₎ were mixed so powder is 30 wt% (Mg content of the overall material 2.00 wt%), the mold of the mixed powder diameter 25mm Was used to form a powder at a press pressure of 49 MPa (500 kgf / cm ² ) and then sintered at 1400 ° C. for 5 hours in an air atmosphere to obtain a tablet as a vapor deposition material.

The density of this tablet was 3.96 g / cm ³ , which was smaller than the tablets of Examples 5, 6, and 7.

When this tablet was subjected to X-ray fluorescence analysis, no change was observed in the concentration of tungsten oxide (WO ₃ ).

Next, this tablet is loaded into an electron gun placed in a vapor deposition device, evacuated to a vacuum of 1 × 10 ⁻³ Pa, and O ₂ gas is brought to a pressure of 2 × 10 ⁻² Pa at a substrate temperature of 300 ° C. The film was introduced into the quartz substrate at a film formation rate of 0.7 mm / sec until the film thickness reached 200 nm. This tablet could be easily deposited without generation of nodules and cracks.

Claims (3)

A vapor deposition material for an optical thin film, which is a compound or a mixture of indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ), and magnesium oxide (MgO). It is a compound or mixture containing indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ) and magnesium oxide (MgO) as main components, and the Mg content is 0.05 wt% to 1.00 wt%. Vapor deposition material for optical thin film characterized. Characterized in that a compound or a mixture of indium oxide (In ₂ O ₃₎ and ratio _of tungsten oxide (WO ₃₎ and magnesium oxide (MgO), a sintered body obtained by sintering at a high temperature oxygen atmosphere or in a high-temperature air atmosphere An optical thin film deposition material.