JP2019163494A - Transparent oxide film, method of manufacturing transparent oxide film, oxide sintered body and transparent resin substrate - Google Patents

Abstract

To provide a transparent oxide film excellent in transparency, water vapor barrier performance, chemical resistance, and flexibility made available using high volume-producibility DC sputtering, and also to provide a method of manufacturing the transparent oxide film, an oxide sintered body for making the film, and a transparent resin substrate using the transparent oxide film.SOLUTION: The amorphous transparent oxide film containing Zn and Sn is provided that has a number-of-metal-atoms ratio Sn/(Zn+Sn) of the amorphous transparent oxide file of 0.44 or more and 0.90 or less, and a film thickness of 100 nm or less. The method of manufacturing the transparent oxide film is provided that uses a target made of Sn-Zn-O-based oxide sintered body to perform sputtering, wherein the number-of-metal-atoms ratio Sn/(Zn+Sn) of Zn and Sn contained in the oxide sintered body used upon sputtering is 0.44 or more and 0.90 or less and the thickness of a file to be formed is 100 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to a transparent oxide film, a method for producing a transparent oxide film, an oxide sintered body, and a transparent resin substrate, and is generally used for display of electronic elements such as liquid crystal elements (LCD), touch panel elements (TP), and electronic paper. The present invention relates to a transparent oxide film used, a method for producing the transparent oxide film, an oxide sintered body for forming the film, and a transparent resin substrate using the transparent oxide film.

  In recent years, in an electronic element such as a liquid crystal element (LCD), a touch panel element (TP), and electronic paper, a transparent conductive layer is formed on a transparent plastic film made of a polymer organic material from an element using a glass substrate with a transparent conductive layer. There is an increasing demand for elements using a film substrate. Advantages include lightness, flexibility, impact resistance, and easy area enlargement.

  However, on the other hand, the film is inferior in the barrier property of water vapor as compared with the glass substrate, and becomes a factor that impedes display performance. As a method for supplementing such inferiority of the water vapor barrier, studies have been made to provide a barrier layer on a transparent plastic film.

Examples of the barrier layer include metal oxide layers such as silicon and aluminum, and are formed by a sputtering method, an ion plating method, a vacuum deposition method, a photo CVD method, or the like. The required water vapor transmission rate for each application is said to be about 0.1 g / m ² / day or less for electronic paper or the like, and about 0.01 g / m ² / day for liquid crystal displays or the like.

  In addition, in order to protect the metal oxide layer from chemicals, studies have been made to provide a chemical resistant layer made of an organic compound on the metal oxide layer. This chemical | medical agent is alkaline aqueous solution or acidic aqueous solution used at the etching process at the time of patterning the transparent electrode of a barrier film with a transparent electrode, for example. In general photolithographic methods, these chemicals are used in all cases. In forming a liquid crystal display, the transparent barrier layer may be partially eroded by the acidic and basic solvents contained in the adhesive or sealing material of the adhesive layer, and the barrier property may be impaired. For this reason, chemical resistance is regarded as important.

For example, Patent Document 1 describes a water vapor barrier transparent resin substrate in which a transparent conductive film made of tin oxide or the like is formed on a transparent film by a sputtering method, and has a water vapor transmission rate of 0.01 g by a mocon method. It is less than / m ² / day and describes that there is no change in transmittance after immersion in a hydrochloric acid solution or an alkaline solution.

Patent Document 2 proposes a barrier film using a laminate of an inorganic film and an organic film. It is described that the water vapor transmission rate at this time is 0.01 g / m ² / day or less, the thickness of the inorganic film is 30 nm to 1 μm, and the thickness of the organic layer is 10 nm to 2 μm.

JP 2005-103768 A Japanese Patent No. 5161470

  In recent years, as the electronic devices have become lighter, thinner and thinner, the water vapor barrier transparent resin substrates used in these displays maintain their water vapor transmission rate and chemical resistance, and these displays are also required to be flexible and thinner. There are many requests. Specifically, the film thickness of the barrier film is required to be 100 nm or less. Naturally, the film thickness of the barrier film is reduced to 100 nm or less, so that the water vapor transmission rate and the chemical resistance are deteriorated. Therefore, it is necessary to improve the water vapor transmission rate and chemical resistance performance.

On the other hand, in Patent Document 1, the water vapor transmission rate is measured by the Mocon method. However, it is difficult to accurately measure 0.01 g / m ² / day or less by the Mocon method, and the actual water vapor of the membrane is not measured. The question remains about barrier properties. In addition, the film used is 200 μm, and the thickness of the barrier film is as thick as 100 to 200 nm, which is inferior in flexibility.

In Patent Document 2, a barrier film using a laminate of an inorganic film and an organic film has been proposed. However, since the film formation process differs between the inorganic film and the organic film, film formation in each other process is necessary. Therefore, it is conceivable that the productivity deteriorates and the characteristics deteriorate due to foreign matters. In addition, in order to achieve a water vapor transmission rate of 0.01 g / m ² / day or less, there is a description that the structure is three or more layers and the organic layer is required to be about 500 nm, which is inferior in flexibility.

  The present invention has been made paying attention to such demands, and has excellent transparency, water vapor barrier performance, excellent chemical resistance, and excellent flexibility by high-productivity direct current sputtering. Another object of the present invention is to provide a transparent oxide film, a manufacturing method thereof, an oxide sintered body for forming a film, and a transparent resin substrate using the transparent oxide film.

  The inventors of the present invention have adjusted the metal atom number ratio and film thickness of Zn and Sn with respect to the above-mentioned problems, and conducted intensive analysis on conditions suitable for chemical resistance and flexibility. As a result, the present invention has been achieved. .

  That is, one embodiment of the present invention is an amorphous transparent oxide film containing Zn and Sn, and has a metal atom number ratio of Sn / (Zn + Sn) of 0.44 to 0.90. The film thickness is 100 nm or less.

  According to one aspect of the present invention, a transparent oxide film having excellent chemical resistance by containing Zn and Sn at the above ratio and having excellent flexibility by having a film thickness of 100 nm or less. It can be.

  At this time, in one embodiment of the present invention, Ta / (Zn + Sn + Ge + Ta) is 0.01 or less and Ge / (Zn + Sn + Ge + Ta) is 0.01 or less in the atomic ratio of Zn, Sn, Ta, and Ge. It may be 0.04 or less.

  Ta and Ge are components derived from the target, which improves the conductivity of the target itself, thereby increasing the deposition rate, and increasing the target density enables stable deposition. It becomes like this.

  In one embodiment of the present invention, the color difference ΔEab change value before and after immersing the transparent oxide film in 5% hydrochloric acid or 5% sodium hydroxide aqueous solution for 5 minutes may be 1.0 or less. it can.

  By satisfying the above requirements, it can be said that the transparent oxide film has excellent chemical resistance.

  In one embodiment of the present invention, the amount of change in film thickness before and after immersing the transparent oxide film in 5% hydrochloric acid or 5% sodium hydroxide aqueous solution for 5 minutes is 2.0 nm or less. You can also.

  By satisfying the above requirements, it can be said that the transparent oxide film has excellent chemical resistance.

In one embodiment of the present invention, the water vapor transmission rate according to the differential pressure method specified in accordance with the JIS standard K7129 method is 0.015 g / m ² / day when the film thickness of the transparent oxide film is 50 nm to 100 nm. When the film thickness of the transparent oxide film is 10 nm or more and less than 50 nm, it can be 0.08 g / m ² / day or less.

  Satisfying the above requirements can be said to be a transparent oxide film having good water vapor barrier performance.

  Another embodiment of the present invention is a Sn—Zn—O-based oxide sintered body used for forming the above-described transparent oxide film by a sputtering method, and includes Zn contained in the oxide sintered body. Sn / (Zn + Sn) of the metal atom number ratio of Sn and Sn is 0.44 or more and 0.90 or less.

  By sputtering using an oxide sintered body having such a composition, a transparent oxide film having excellent chemical resistance can be formed.

  At this time, in another aspect of the present invention, Ta and Ge are further contained, and Ta / (Zn + Sn + Ge + Ta) of Ta and Zn, Sn, Ge has a metal atom number ratio of 0.01 or less, and Ge and Zn, Sn, Ge / (Zn + Sn + Ge + Ta) of the Ta metal atom number ratio may be 0.04 or less.

  In this way, the film forming speed is improved by improving the conductivity of the target itself, and the film can be stably formed by increasing the target density.

  Another aspect of the present invention is a method for producing a transparent oxide film obtained by sputtering using a target composed of a Sn—Zn—O-based oxide sintered body to obtain a transparent oxide film, which is used during sputtering. Sn / (Zn + Sn) of the metal atom number ratio between Zn and Sn contained in the oxide sintered body is 0.44 or more and 0.90 or less, and the film thickness is 100 nm or less.

  According to another aspect of the present invention, a transparent oxide that has excellent chemical resistance by containing Zn and Sn in the above proportions, and also has excellent flexibility by having a film thickness of 100 nm or less. A membrane can be formed.

  Another aspect of the present invention is a transparent resin substrate in which the above-described transparent oxide film is formed on at least one surface of a transparent resin base material.

  According to another aspect of the present invention, a transparent resin substrate having both excellent water vapor barrier properties and chemical resistance by forming the above-described transparent oxide film and excellent in flexibility can be obtained. .

  According to the present invention, a transparent oxide film having good transparency, water vapor barrier performance, and excellent chemical resistance by DC sputtering having high mass productivity and versatility, and a manufacturing method thereof, An oxide sintered body for forming a film and a transparent resin substrate using a transparent oxide film can be provided.

Hereinafter, the transparent oxide film, the method for producing the transparent oxide film, the oxide sintered body, and the transparent resin substrate according to the present invention will be described in the following order. In addition, this invention is not limited to the following examples, In the range which does not deviate from the summary of this invention, it can change arbitrarily.
1. Transparent oxide film 2. Oxide sintered body 3. Production method of transparent oxide film Transparent resin substrate

<1. Transparent oxide film>
One embodiment of the present invention is an amorphous transparent oxide film containing Zn and Sn, which has a metal atom number ratio of Sn / (Zn + Sn) of 0.44 to 0.90. The thickness is 100 nm or less. By containing Zn and Sn at such a ratio, a transparent oxide film having excellent chemical resistance and having excellent flexibility can be obtained by setting the film thickness to 100 nm or less.

  The amorphous transparent oxide film of the present invention is also used as a water vapor barrier film. The surface of a flexible display element such as a liquid crystal display element or electronic paper such as a liquid crystal display element or electronic paper is covered as a metal oxide film by a sputtering method and used for the purpose of preventing alteration by blocking water vapor.

  This transparent oxide film needs to block water vapor. Therefore, it is preferable that the transparent oxide film is as dense as possible, is thin and uniform, and has few defects (gap) through which moisture passes. For this reason, the transparent oxide film is formed by a sputtering method. The transparent oxide film formed by this sputtering method is preferably amorphous as disclosed in Patent Document 1. This is because when the transparent oxide film is a crystalline film, a crystal grain boundary exists in the film, and water vapor permeates through the crystal grain boundary, so that the water vapor barrier performance is deteriorated.

  In addition, the transparent oxide film requires acid resistance and alkali resistance in order to protect the metal oxide layer from chemicals. When the metal oxide layer is patterned into an arbitrary shape, it is carried out by a general photolithography method. This method is based on the premise that the transparent oxide film does not dissolve and the film is not damaged by chemicals because an alkaline aqueous solution or an acidic aqueous solution is used in all cases. In addition, when forming a liquid crystal display, the transparent oxide film is partially eroded by the penetration of acidic and alkaline solvents contained in the adhesive and sealant of the adhesive layer, which impairs the barrier properties. Is emphasized.

  In Patent Document 1, a tin oxide-based film is proposed as the transparent oxide film. However, when a tin oxide-based film is formed by a sputtering method, a target material constituting a sputtering target used for sputtering is a film and The same component, tin oxide, is used. Although this tin oxide target material generally has high acid resistance, the relative density of the target material is low, and there are many problems such that the target material cannot be stably formed due to cracking of the target material during sputtering. In the transparent oxide film according to the present invention, the above-mentioned concern has been solved by using a Sn—Zn—O-based sputtering target described later.

  That is, the transparent oxide film according to an embodiment of the present invention is an amorphous transparent oxide film containing Zn and Sn, and Sn / (Zn + Sn) is 0.44 in terms of the number of metal atoms. It is characterized by being 0.90 or less.

By setting the metal atom number ratio as Sn / (Zn + Sn) to 0.44 or more and 0.90 or less, good water vapor transmission rate and chemical resistance can be obtained. Zinc oxide (ZnO) is easily dissolved in chemicals such as acids and alkalis, and has a drawback of poor resistance to chemicals such as acids and alkalis. For example, high-definition patterning processing by wet etching is difficult. However, the tin oxide (SnO ₂ ) system has extremely high chemical resistance. Therefore, chemical resistance such as acid and alkali can be obtained by using SnO _{2 as} the main component of the amorphous transparent oxide film containing Zn and Sn.

When the metal atom number ratio Sn / (Sn + Zn) is less than 0.44, ZnO is more likely to be dissolved in acidic or alkaline aqueous solution than SnO ₂ and chemical resistance is poor.

Further, when the metal atom number ratio Sn / (Sn + Zn) exceeds 0.90, the SnO ₂ ratio is not increased so that the relative density as a sputtering target material is low, and cracking defects of the sintered body occur during DC sputtering. There is a high possibility of doing.

  The film thickness of the transparent oxide film according to an embodiment of the present invention is preferably 100 nm or less, and more preferably 90 nm or less. By setting it as such a film thickness, the oxide film excellent in flexibility can be provided. The lower limit of the thickness of the oxide film according to one embodiment of the present invention is 10 nm.

  When the film thickness of the transparent oxide film according to an embodiment of the present invention is thinner than 10 nm, the film is too thin, and it is difficult to guarantee the quality of the entire film. And affects the barrier performance. Moreover, when a film thickness exceeds 100 nm, the cause of the curl of the film substrate by a film stress, the deterioration of flexibility, and the fall of the transmittance | permeability are caused. Therefore, in view of productivity and cost, the film thickness is preferably 100 nm or less, and more preferably 90 nm or less. Therefore, use at 10 to 100 nm matches the needs for flexibility, weight reduction and thinning, and is the optimum film thickness for use during device assembly and mass production.

  The transparent oxide film according to an embodiment of the present invention further has a metal atom number ratio of Ta of Ta / (Zn + Sn + Ge + Ta) of 0.01 or less and Ge of Ge / (Zn + Sn + Ge + Ta) of 0.04 or less. It may be included as a percentage. Even if Ta or Ge is contained, the crystallization temperature is 600 ° C. or higher, so that an amorphous film structure is easily obtained. In addition, since the crystallization temperature is high, the amorphous state can be easily maintained even when there is a thermal influence in the mass production process. Further, adding Ta or Ge in the above ratio has an effect of further improving the characteristics of the sputtering target containing Zn and Sn.

  Hereinafter, the additive elements (Ta, Ge) will be briefly described. The sputtering target material is formed by bonding (bonding) an oxide sintered body composed only of Sn—Zn to a backing plate made of a copper material, a stainless steel material, or the like using a bonding material such as indium (In). can get.

A target composed only of Sn—Zn has insufficient conductivity and may have a large specific resistance value. This is because it is necessary to perform sputtering with a larger energy as the specific resistance value is larger at the time of sputtering, and the deposition rate cannot be increased. Therefore, it is necessary to increase the conductivity of the target. Since Zn ₂ SnO ₄ , ZnO, and SnO ₂ are poorly conductive materials in the target, even if the compounding ratio is adjusted to adjust the compound phase and the amount of ZnO and SnO ₂ , the conductivity is greatly improved. I can't do it.

Therefore, it is preferable to add Ta (tantalum). Since Ta is substituted for Zn in the ZnO phase, Zn in the Zn ₂ SnO ₄ phase or Sn, and Sn in the SnO ₂ phase, it dissolves, so that the ZnO phase of the wurtzite crystal structure, Zn of the spinel crystal structure A compound phase other than the ₂ SnO ₄ phase and the SnO ₂ phase having a rutile crystal structure is not formed. By adding Ta, the conductivity is improved while maintaining the density of the oxide sintered body.

  In addition, the sintered density of the target composed only of Sn—Zn is around 90%, which may not be sufficient. When the density of the target is low, there is a problem that the film cannot be stably formed because the target is broken during sputtering.

Therefore, it is preferable to add a predetermined amount of Ge (germanium). In the target, Ge substitutes for Zn in the ZnO phase, Zn or Zn in the Zn ₂ SnO ₄ phase, or Sn in the SnO ₂ phase and dissolves in a solid solution, so that the ZnO phase having a wurtzite crystal structure, spinel type Compound phases other than the Zn ₂ SnO ₄ phase having a crystal structure and the SnO ₂ phase having a rutile crystal structure are not formed. The addition of Ge has the effect of densifying the target. Thereby, the sintered density of the target can be made higher.

  Accordingly, the oxide sintered body further contains Ta and Ge, and Ta / (Zn + Sn + Ge + Ta) of the metal atom number ratio of Ta and Zn, Sn, Ge is 0.01 or less, and the Ge, Zn, Sn, It is preferable that Ge / (Zn + Sn + Ge + Ta) of the Ta metal atom number ratio is 0.04 or less. Note that the approximate lower limit value for obtaining the above effect by addition of Ta and Ge is 0.0005 in terms of the number of metal atoms for both Ta and Ge.

When Ta / (Zn + Sn + Ge + Ta) of the metal atom number ratio of Ta and Zn, Sn, Ge is larger than 0.01, another compound phase, for example, a compound phase such as Ta ₂ O ₅ or ZnTa ₂ O ₆ is generated. The conductivity cannot be improved significantly. Further, when Ge / (Zn + Sn + Ge + Ta) of the metal atom number ratio of Ge and Zn, Sn, Ta is larger than 0.04, another compound phase, for example, a compound phase such as Zn ₂ Ge ₃ O ₈ is generated. The density of the oxide sintered body is reduced, and the target is easily broken during sputtering.

  Sputtering using a target to which Ta and Ge are added does not affect the formed transparent oxide film. For example, the influence of water vapor transmission rate and chemical resistance is not confirmed. Therefore, Sn / (Zn + Sn) is 0.40 or more and less than 0.90 in terms of the number of metal atoms, Ta is Ta / (Zn + Sn + Ge + Ta) is 0.01 or less, Ge is Ge / (Zn + Sn + Ge + Ta) is 0.04. Even if it is contained in the following proportions, it is possible to obtain an amorphous transparent oxide film having good chemical resistance without deteriorating the water vapor barrier performance.

  As described above, the transparent oxide film according to one embodiment of the present invention has chemical resistance. The chemical resistance is evaluated by the amount of change in film thickness before and after immersion in the chemical solution and the color difference ΔEab. In these evaluations, when the transparent oxide film according to one embodiment of the present invention is formed on a transparent glass substrate by a sputtering method and immersed in an acidic aqueous solution or an alkaline aqueous solution, the amount of change in film thickness before and after being immersed in a chemical solution Is 2.0 nm or less, and the color difference of the transparent oxide film before and after the immersion is preferably such that the value of ΔEab in the L * a * b * color system is 1.0 or less.

  Specifically, the chemical resistance has confirmed the chemical resistance with respect to an acid and an alkali. The acid resistance was 5% hydrochloric acid, and the alkali resistance was immersed in a 5% sodium hydroxide solution for 5 minutes, and the color difference ΔEab before and after the evaluation was evaluated. If this color difference ΔEab is large, the color changes before and after the treatment, and it is presumed that the transparent oxide film is eluted and discolored by the chemical. If the color difference ΔEab change value is 1.0 or less, it can be judged that the transparent oxide film is less eluted by chemicals and has chemical resistance. The color difference ΔEab change value is more preferably 0.5 or less.

The color difference is evaluated using the L * a * b * color system (CIE 1976). In the L * a * b * color system, L * represents lightness, a *, b * represents hue and saturation, and is represented by chromaticity. L * is represented by a numerical value from 0 to 100. The larger it is, the more white it becomes. a * is the axis from red to green, + a is the red direction, -a is the green direction, b * is the axis from yellow to blue, + b is the yellow direction, -b is the blue direction, When both a * b * are 0, the color is achromatic. The color difference ΔEab is calculated by the CIE 1976 color difference calculation formula. In the transparent oxide sputtered film before and after chemical immersion, L *, a *, b * are measured, and the difference before and after the difference is ΔL *, Δa *, Δb *, and the color difference ΔEab is ((ΔL *) ² + ( Δa *) ² + (Δb *) ² ) ^1/2 .

  The thickness change before and after being immersed in the chemical solution was acid resistance of 5% hydrochloric acid, alkali resistance was immersed in a 5% sodium hydroxide solution for 5 minutes each, and the chemical solution in which the sample was immersed was ICP-AES. The amount of dissolution of Zn and Sn can be confirmed by the method (ICPS-8100, manufactured by Shimadzu Corporation), and the amount of film thickness reduction (film change amount) can be estimated from the results, film formation area and film density. The acid resistance is 5% hydrochloric acid, and the alkali resistance is as long as the decrease in film thickness (film change amount) after being immersed in a 5% sodium hydroxide solution for 5 minutes is 2.0 nm or less. It can be judged that there is chemical nature.

As described above, the tin oxide (SnO ₂ ) system has extremely high chemical resistance. By making an amorphous transparent oxide film containing Zn and Sn into Sn / (Zn + Sn) 0.44 or more and 0.9 or less in Sn / (Zn + Sn) as a main component from SnO ₂ as a main component. The color difference ΔEab change value can be 1.0 or less, and the film change amount can also be 2.0 nm or less.

  In the transparent oxide film according to one embodiment of the present invention, the water vapor transmission rate is affected by the film thickness. As the water vapor transmission rate increases, the water vapor transmission rate decreases as the film thickness increases. Therefore, the film thickness is appropriately set in consideration of the necessary water vapor transmission rate.

In the transparent oxide film according to an embodiment of the present invention, when the water vapor transmission rate by the differential pressure method specified in accordance with the JIS standard K7129 method of the transparent oxide film is 50 nm to 100 nm, 015g ^/ m 2 ^/ day or less and becomes, in less than 10 nm up to 50 nm, preferably not more than 0.08g ^/ m 2 ^/ day.

  As mentioned above, according to the transparent oxide film concerning one embodiment of the present invention, it has both excellent water vapor barrier performance and chemical resistance in DC sputtering with high mass productivity, and is transparent with excellent flexibility. It becomes an oxide film.

<2. Oxide sintered body>
Next, an Sn—Zn—O-based oxide sintered body used for forming a transparent oxide film according to an embodiment of the present invention by a sputtering method will be described. The oxide sintered body according to one embodiment of the present invention is a Sn—Zn—O-based oxide sintered body configured as a sputtering target used when sputtering an oxide sputtered film.

  And Sn / (Zn + Sn) of the metal atom number ratio of Zn and Sn contained in the said oxide sintered compact is 0.44 or more and 0.9 or less, It is characterized by the above-mentioned. The characteristics of the oxide sintered body are inherited by the transparent oxide film.

  The oxide sintered body further contains Ta and Ge, and Ta / (Zn + Sn + Ge + Ta) of the metal atom number ratio of Ta and Zn, Sn, Ge is 0.01 or less, and the Ge, Zn, Sn, It is preferable that Ge / (Zn + Sn + Ge + Ta) of the Ta metal atom number ratio is 0.04 or less. The technical significance of the composition range of the oxide sintered body according to one embodiment of the present invention is as described above.

  The oxide sintered body according to one embodiment of the present invention is not limited to the following, but a specific method for manufacturing the sintered body is given. First, an oxide powder of Zn, an oxide powder of Sn, and an oxide powder containing additive elements of Ta and Ge are adjusted and mixed so as to have the preferable metal atom number ratio described above. Then, the granulated powder is mixed with pure water or ultrapure water, an organic binder, a dispersant, and an antifoaming agent.

Next, the raw material powder is wet pulverized using a bead mill apparatus or the like into which hard ZrO ₂ balls are charged, and then mixed and stirred to obtain a slurry. A granulated powder can be obtained by spraying and drying the obtained slurry with a spray dryer or the like.

Next, the granulated powder is pressure-molded to obtain a molded body. In order to remove voids between the particles of the granulated powder, pressure molding is performed at a pressure of about 294 MPa (3.0 ton / cm ² ), for example. The method of pressure molding is not particularly limited, but for example, it is preferable to use a cold isostatic press (CIP) capable of filling the granulated powder into a rubber mold and applying a high pressure. .

Next, the molded body is fired to obtain an oxide sintered body. The above-mentioned compact is fired at a predetermined temperature rise rate in the firing furnace at a predetermined temperature and for a predetermined time to obtain an oxide sintered body. For example, the firing is performed in an atmosphere in a firing furnace in the air. The molded body is preferably fired at a rate of temperature increase from 700 ° C. to a predetermined sintering temperature in the sintering furnace at a rate of 0.3 to 1.0 ° C./min. This is because there is an effect of promoting diffusion of ZnO, SnO ₂ and Zn ₂ SnO ₄ compound, improving sinterability and improving conductivity. Further, by such a heating rate in the high temperature region, there is also the effect of suppressing the volatilization of the ZnO and _Zn 2 SnO _4.

  When the rate of temperature increase in the sintering furnace is less than 0.3 ° C./min, the diffusion of the compound decreases. On the other hand, when the temperature exceeds 1.0 ° C./min, the rate of temperature rise is high, so that the formation of the compound is incomplete and a dense oxide sintered body cannot be produced.

The sintering temperature after the temperature rise is preferably 1300 ° C. or higher and 1400 ° C. or lower. When the sintering temperature is less than 1300 ° C., the temperature is too low and the grain boundary diffusion of sintering in the ZnO, SnO ₂ , Zn ₂ SnO ₄ compound does not proceed. On the other hand, even when the temperature exceeds 1400 ° C., grain boundary diffusion is promoted and sintering proceeds, but volatilization of the Zn component cannot be suppressed, leaving large voids inside the oxide sintered body. become.

The holding time after the temperature rise is preferably 15 hours or more and 25 hours or less. When the holding time is less than 15 hours, sintering is incomplete, resulting in a sintered body with large distortion and warpage, and grain boundary diffusion does not proceed and sintering does not proceed. As a result, a dense sintered body cannot be produced. On the other hand, when it exceeds 25 hours, the volatilization of ZnO and Zn ₂ SnO ₄ increases, resulting in a decrease in the density of the oxide sintered body, a deterioration in work efficiency, and a high cost.

  From the above, according to the oxide sintered body according to one embodiment of the present invention, both high water vapor barrier performance and chemical resistance are obtained by high-productivity direct current sputtering, and the flexibility is also excellent. A transparent oxide film can be obtained.

  In addition, the sputtering target comprised from oxide sintered compact is produced by the following. First, a processed body (target material) is obtained by mechanically grinding the above-described oxide sintered body to obtain a desired size. A sputtering target is obtained by bonding the obtained processed body to a backing plate made of a copper material, a stainless material, or the like using a bonding material such as indium (In). The sputtering target may be a laminate of a plurality of oxide sintered bodies.

<3. Manufacturing method of transparent oxide film>
Next, the manufacturing method of the transparent oxide film which concerns on one Embodiment of this invention is demonstrated. The method for producing a transparent oxide film according to an embodiment of the present invention includes sputtering using a Sn—Zn—O-based oxide sintered body to obtain an amorphous transparent oxide film.

  And the sintered body of Sn / (Zn + Sn) of the metal atom number ratio of Zn and Sn contained in the above-mentioned oxide sintered body used at the time of sputtering of the transparent oxide film is 0.44 or more and 0.9 or less, Prepare a configured target. The technical significance of the above range is as described above.

  The transparent oxide film is formed to have a thickness of 100 nm or less, preferably 90 nm or less. With such a film thickness, it is possible to provide a transparent oxide film having good water vapor barrier performance and excellent chemical resistance and more excellent flexibility.

  Sputtering may be performed using a sputtering target composed of the above-described oxide sintered body. The sputtering apparatus is not particularly limited, and a direct current magnetron sputtering apparatus or the like can be used.

As sputtering conditions, the degree of vacuum in the chamber is adjusted to 1 × 10 ⁻⁴ Pa or less. An inert gas is introduced into the atmosphere in the chamber. The inert gas is argon gas or the like, and preferably has a purity of 99.999% by mass or more. The inert gas contains 4 to 10% by volume of oxygen with respect to the total gas flow rate. Since the oxygen concentration affects the surface resistance value of the film, the oxygen concentration is set to a predetermined resistance value. Thereafter, a predetermined direct current power source is used to put between the sputtering target and the base material, plasma is generated by direct current pulsing, and sputtering is performed to form a film. Note that the film thickness is controlled by the film formation time.

  As mentioned above, according to the manufacturing method of the transparent oxide film concerning one embodiment of the present invention, it has good transparency, water vapor barrier performance, and excellent chemical resistance by DC sputtering with high mass productivity. A transparent oxide film having excellent flexibility can be obtained.

<4. Transparent resin substrate>
In the transparent resin substrate according to an embodiment of the present invention, a transparent oxide film having a Zn / Sn metal atom number ratio of Sn / (Zn + Sn) of 0.44 or more and 0.9 or less is at least one of the base materials. The film is formed on the surface. The film thickness of the transparent oxide film is 100 nm or less, preferably 90 nm or less.

  As the transparent substrate, polyethylene terephthalate, polyethylene, naphthalate, polycarbonate, polysulfone, polyethersulfone, polyarylate, cycloolefin polymer, fluororesin, polypropylene, polyimide resin, epoxy resin, and the like can be used. The thickness of the transparent resin substrate is not particularly limited, but is preferably 50 to 150 μm in view of flexibility, cost, and device needs.

  The sputtering method for the transparent resin substrate may be performed as described in the method for producing the transparent oxide film. The technical significance such as the preferred metal atom number ratio and film thickness of Zn and Sn is as described above.

  Moreover, the transparent resin substrate according to an embodiment of the present invention is a substrate in which a sputtered film of an amorphous transparent oxide containing Zn and Sn is formed on at least one surface of the base material. You may laminate | stack through another film | membrane. For example, a silicon oxide film, a silicon nitride oxide film, a resin film, a wet coat film, a metal film, an oxide film, or the like is formed on the substrate, and then the transparent oxide film is used as a chemical resistant layer. You may form in at least one.

  As described above, for example, a liquid crystal element (LCD), a touch panel element (TP), electronic paper, or the like, which is one of flexible display elements, can be formed using the transparent resin substrate according to an embodiment of the present invention. is there.

  As mentioned above, according to the transparent resin substrate which concerns on one Embodiment of this invention, it has both the outstanding water vapor | steam barrier performance and chemical-resistance in DC sputtering with high mass-productivity, and is also excellent in flexibility. It becomes a substrate.

  Hereinafter, examples of the present invention will be specifically described with reference to comparative examples. However, the technical scope of the present invention is not limited to the description of the following examples, and changes are made within the scope suitable for the present invention. Of course, it is also possible to carry out by adding.

In the following examples, SnO ₂ powder and ZnO powder were used. In addition, when adding an additive element, Ta ₂ O ₅ powder was used as the additive element Ta and GeO ₂ powder was used as the additive element Ge.

(Example 1)
In Example 1, a sputtering target (manufactured by Sumitomo Metal Mining Co., Ltd.) was prepared using a sintered body manufactured so that tin oxide had a metal atomic ratio Sn / (Sn + Zn) of 0.49. The film was formed by sputtering using a sputtering apparatus. As this sputtering apparatus, a direct current magnetron sputtering apparatus (manufactured by ULVAC, SH-550 type) was used. A PEN film (Teijin's Q65 thickness 50 μm) was used as the resin film substrate.

The oxide film was formed under the following conditions. The resin film base material was disposed immediately above the cathode, and the distance between the target and the resin film substrate was 80 mm. When the degree of vacuum in the chamber reaches 2 × 10 ⁻⁴ Pa or less, argon gas having a purity of 99.9999% by mass is introduced into the chamber to a gas pressure of 0.6 Pa and argon containing 5% oxygen. In a gas, DC power source (MDX, manufactured by DELTA) is used as a DC power source, DC power 1500W adopting 20kHz DC pulsing is input between the sputtering target and the film substrate, and plasma is generated by DC pulsing. Then, a transparent oxide film having a thickness of 100 nm was formed on the film substrate by sputtering.

  During the film formation, the attached resin film was kept stationary. The water vapor permeability of the prepared transparent oxide film was measured by a differential pressure method (DELTATAPRM-UH manufactured by Technolox).

  Next, the base material was a glass substrate (Corning EAGLE XG thickness 0.70 mm), and a transparent oxide film having the same film thickness was obtained under the same conditions as described above.

  The crystallinity of the formed transparent oxide film was measured by X-ray diffraction, and the diffraction peak was observed. The water vapor transmission rate was measured by a differential pressure method (DELTATAPRM-UH manufactured by Technolox). Moreover, the transmittance | permeability was made into the visible light average transmittance | permeability in wavelength 550nm, and it measured with the spectrophotometer (JASCO Corporation V-670).

  The chemical resistance was evaluated by the following method. A 5% HCl aqueous solution and a 5% NaOH aqueous solution were respectively prepared in a 200 ml Teflon beaker, and a glass substrate with a transparent oxide film was immersed in the 5% HCl aqueous solution or the 5% NaOH aqueous solution. At this time, the 5% HCl aqueous solution or 5% NaOH aqueous solution was in a stationary state without stirring, and the temperature was 23 ° C. The immersion time was measured after taking out the glass substrate after 5 minutes.

  The amount of change in film thickness is determined by measuring the amount of film dissolved (the amount of Zn and Sn dissolved) by ICP-AES method (ICPS-8100, manufactured by Shimadzu Corp.), and the results, film formation area and film density. The amount of change in film thickness was calculated. In addition, the color difference ΔEab was measured before and after immersion in the L * a * b * color system using a spectrocolorimeter (Konica Minolta Co., Ltd. model: CM-5) to calculate the color difference ΔEab. In the chemical resistance evaluation, a glass substrate with a transparent oxide film formed so as not to dissolve the base material was used. The results are shown in Table 1.

(Example 2)
In Example 2, a transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film thickness was 90 nm by sputtering. The results are shown in Table 1.

(Example 3)
In Example 3, a transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film thickness was 50 nm by sputtering. The results are shown in Table 1.

Example 4
In Example 4, a transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film thickness was 30 nm by sputtering. The results are shown in Table 1.

(Example 5)
In Example 5, a transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film thickness was 10 nm by sputtering. The results are shown in Table 1.

(Example 6)
In Example 6, a transparent oxide film was obtained in the same manner as in Example 1 except that a transparent oxide film having a metal atom number ratio Sn / (Zn + Sn) of 0.68 was formed by sputtering to a film thickness of 50 nm. The measurement was carried out. The results are shown in Table 1.

(Example 7)
In Example 7, a transparent oxide film having a metal atom number ratio Sn / (Zn + Sn) of 0.49, Ta / (Zn + Sn + Ge + Ta) of 0.01, and Ge / (Zn + Sn + Ge + Ta) of 0.04 is formed by sputtering to a thickness of 10 nm. A transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film was formed. The results are shown in Table 1.

(Example 8)
In Example 8, a transparent oxide film having a metal atom number ratio Sn / (Zn + Sn) of 0.90, Ta / (Zn + Sn + Ge + Ta) of 0.01, and Ge / (Zn + Sn + Ge + Ta) of 0.04 is formed by sputtering to a thickness of 10 nm. A transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film was formed. The results are shown in Table 1.

Example 9
In Example 9, a transparent oxide film having a metal atomic ratio Sn / (Zn + Sn) of 0.90, Ta / (Zn + Sn + Ge + Ta) of 0.01, and Ge / (Zn + Sn + Ge + Ta) of 0.04 is formed by sputtering to a film thickness of 100 nm. A transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film was formed. The results are shown in Table 1.

(Comparative Example 1)
In Comparative Example 1, a transparent oxide film was obtained in the same manner as in Example 1 except that a transparent oxide film having a metal atom number ratio Sn / (Zn + Sn) of 0.18 was formed by sputtering, and measurement was performed. Carried out. The results are shown in Table 1.

(Comparative Example 2)
In Comparative Example 2, a transparent oxide film was obtained in the same manner as in Example 1 except that a transparent oxide film having a metal atomic ratio Sn / (Zn + Sn) of 0.30 was formed by sputtering, and measurement was performed. Carried out. The results are shown in Table 1.

(Comparative Example 3)
In Comparative Example 3, a transparent oxide film having a metal atomic ratio Sn / (Zn + Sn) of 0.33, Ta / (Zn + Sn + Ge + Ta) of 0.01, and Ge / (Zn + Sn + Ge + Ta) of 0.04 is formed by sputtering to a film thickness of 10 nm. A transparent oxide film was obtained and measured in the same manner as in Example 1 except that the film was formed. The results are shown in Table 1.

From Table 1, in Examples 1 to 9 included in the present invention, the water vapor transmission rate by the differential pressure method specified in accordance with the JIS standard K7129 method is a film thickness of 50 to 100 nm (Examples 1, 2, 3, 6, and 9). Then, it becomes 0.015 g / m ² / day or less, and when the film thickness is less than 50 nm (Examples 4, 5, 7, and 8), it becomes 0.08 g / m ² / day or less and has a good water vapor barrier performance I understand that. Furthermore, it was found that the color difference ΔEab in the chemical resistance evaluation was 1.0 or less, and the film change amount was 2.0 nm or less, thus having good chemical resistance. Further, the transmittance measured at a wavelength of 550 nm was 80% or more, and it was found to have transparency. The crystallinity was amorphous in all of Examples 1 to 9 as a result of X-ray diffraction measurement.

  On the other hand, in Comparative Example 1 where Sn / (Zn + Sn) of the transparent oxide film was 0.19, the transparent oxide film was dissolved in acid or alkali in the chemical resistance evaluation.

  In Comparative Example 2 where Sn / (Zn + Sn) of the transparent oxide film is 0.30 and Comparative Example 3 where Sn / (Zn + Sn) of the transparent oxide film is 0.33, the resistance to chemical resistance evaluation In the alkalinity evaluation, the value of ΔEab exceeded 1.0, and the amount of film loss exceeded 2.0 nm. Therefore, it was found that the transparent oxide films of Comparative Example 2 and Comparative Example 3 were inferior in chemical resistance.

  As described above, according to the present invention, a transparent oxide film having excellent transparency, good water vapor barrier performance, and chemical resistance can be obtained by DC sputtering with high mass productivity.

  Although one embodiment and each example of the present invention have been described in detail as described above, it will be understood by those skilled in the art that many modifications that do not substantially depart from the novel matters and effects of the present invention are possible. It will be easy to understand. Therefore, all such modifications are included in the scope of the present invention.

  For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Further, the transparent oxide film, the method for producing the transparent oxide film, the oxide sintered body, and the transparent resin substrate are not limited to those described in one embodiment and each example of the present invention, and various modifications are made. Is possible.

  By using the transparent oxide film according to the present invention, it becomes possible to form a water vapor barrier transparent resin substrate, and by using the water vapor barrier transparent resin substrate, it has a degree of freedom in shape, an aspect display, and the like. In addition, a liquid crystal display element, electronic paper, and the like can be manufactured. Therefore, the present invention is extremely valuable industrially.

Claims (9)

An amorphous transparent oxide film containing Zn and Sn,
In the metal atom number ratio, Sn / (Zn + Sn) is 0.44 or more and 0.90 or less,
A transparent oxide film having a thickness of 100 nm or less. Furthermore, it contains Ta and Ge,
In the atomic ratio of Zn, Sn, Ta, and Ge,
The transparent oxide film according to claim 1, wherein Ta / (Zn + Sn + Ge + Ta) is 0.01 or less and Ge / (Zn + Sn + Ge + Ta) is 0.04 or less.   3. The transparent according to claim 1, wherein the transparent oxide film has a color difference ΔEab change value of 1.0 or less before and after immersing the transparent oxide film in 5% concentration hydrochloric acid or 5% concentration sodium hydroxide aqueous solution for 5 minutes. Oxide film.   The amount of change in film thickness before and after immersing the transparent oxide film in 5% concentration hydrochloric acid or 5% concentration sodium hydroxide aqueous solution for 5 minutes is 2.0 nm or less. 2. The transparent oxide film according to item 1. The water vapor transmission rate by the differential pressure method specified in accordance with the JIS standard K7129 method is 0.015 g / m ² / day or less when the film thickness of the transparent oxide film is 50 nm to 100 nm.
5. The transparent oxide film according to claim 1, wherein the transparent oxide film has a thickness of 0.08 g / m ² / day or less when the film thickness is 10 nm to less than 50 nm. An Sn-Zn-O-based oxide sintered body used for forming the transparent oxide film according to any one of claims 1 to 5 by a sputtering method,
An oxide sintered body characterized in that Sn / (Zn + Sn) in the metal atom number ratio of Zn and Sn contained in the oxide sintered body is 0.44 or more and 0.90 or less. Furthermore, it contains Ta and Ge,
Ta / (Zn + Sn + Ge + Ta) of the metal atom number ratio of Ta and Zn, Sn, Ge is 0.01 or less,
7. The oxide sintered body according to claim 6, wherein Ge / (Zn + Sn + Ge + Ta) in the metal atom number ratio of Ge to Zn, Sn, and Ta is 0.04 or less. Sputtering using a target made of a Sn—Zn—O-based oxide sintered body to obtain a transparent oxide film,
Sn / (Zn + Sn) of the metal atom number ratio of Zn and Sn contained in the oxide sintered body used at the time of sputtering is 0.44 or more and 0.90 or less,
The manufacturing method of the transparent oxide film whose film thickness to form into a film is 100 nm or less.   The transparent resin substrate in which the transparent oxide film of any one of Claim 1 thru | or 5 is formed in the at least one surface of the transparent resin base material.