CN117303888A - Oxide target material and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of target materials and discloses an oxide target material, in which the content of zinc oxide is 25~30wt%, the content of titanium oxide is 25~30wt%, and the content of aluminum oxide is 5~12.5wt%. The balance is indium tin oxide. Add zinc oxide, titanium oxide and aluminum oxide powder to pure water and disperse to obtain slurry I; emulsify slurry I and then ball mill to obtain slurry II; add indium tin oxide powder to water and disperse to obtain slurry Material III; emulsified slurry III, then mixed with slurry II and binder, ball milled to obtain ball abrasives; spray dried ball abrasives, and then granulated to obtain pellets; after the pellets are shaped, sintered to obtain oxides target material. The ITO target material provided by the invention has low resistivity, and the preparation method is simple to operate and low in cost.

Description

Oxide target material and preparation method thereof

Technical field

The invention belongs to the technical field of target materials, and specifically relates to oxide target materials and preparation methods thereof.

Background technique

ITO target, that is, indium tin oxide target, is a black-gray ceramic semiconductor material formed by mixing indium oxide and tin oxide powder according to a certain proportion, processing and shaping through a series of production processes, and then sintering at high temperature. As an n-type semiconductor material, indium tin oxide has high electrical conductivity, excellent visible light transmittance, strong mechanical hardness and good chemical stability. It is mainly used to make liquid crystal displays, flat panel displays, plasma displays, and touch screens. , electronic paper, organic light-emitting diodes, solar cells, antistatic coatings, EMI shielding transparent conductive coatings, various optical coatings, etc. In order to further improve the conductive properties of ITO targets, ion doping ITO targets is a common method. Choosing appropriate ion doping can effectively reduce resistivity. For example: the patent document with the publication number CN103345977A discloses a preparation method of silver-doped ITO thin film; the patent document with the publication number CN114032517A discloses the preparation method of rare earth ion doped ITO target material; the patent document with the publication number CN115353369A discloses a microwave The method prepares nickel-aluminum doped ITO target material; the patent document with the publication number CN114591070A discloses the preparation method of high-purity Mo-doped ITO target material.

Oxide targets are also a research hotspot. The density, grain size, composition and structural uniformity of the oxide target affect various electrical and optical properties of sputtered films, which has attracted great attention from a large number of researchers and industry insiders. Reducing the resistivity of oxide targets is one of the current key research directions. The patent document with publication number CN115974530A discloses a low resistivity and high mobility oxide target material, which is composed of praseodymium oxide, indium oxide, gallium oxide, and zinc oxide. Because more rare precious metal oxides are used, the cost is higher.

Contents of the invention

The purpose of the present invention is to provide an oxide target material and a preparation method thereof to achieve low resistivity and low cost of the oxide target material.

In order to achieve the above objects, the present invention provides the following specific technical solutions.

First, the present invention provides an oxide target material, in which the content of zinc oxide is 25~30wt%, the content of titanium oxide is 25~30wt%, the content of aluminum oxide is 5~12.5wt%, and the balance is indium oxide. tin.

In a further preferred solution, the outer diameter of the oxide target material is 180~210mm.

In a further preferred embodiment, the resistivity of the oxide target material is 2.7×10 ^-5 ~3.2×10 ^-5 Ω·m.

Secondly, the present invention provides a method for preparing the above-mentioned oxide target, which includes the following steps:

Add zinc oxide, titanium oxide, and aluminum oxide powder to pure water and disperse to obtain slurry I;

Emulsify slurry I and then ball mill to obtain slurry II;

Add indium tin oxide powder to water and disperse to obtain slurry III;

Emulsify slurry III, then mix it with slurry II and binder, and ball-mill to obtain ball abrasive;

Spray dry the ball abrasive and then granulate to obtain pellets;

After the pellets are formed, they are sintered.

In a further preferred embodiment, the solid content of the slurry I is 25~50wt%.

In a further preferred embodiment, the particle size D50 of the slurry II is 0.3~1 μm.

In a further preferred embodiment, the solid content of the slurry III is 25~50wt%.

In a further preferred embodiment, the particle size D50 of the ball abrasive is 0.3~1 μm.

In a further preferred embodiment, the solid content of the ball abrasive is 35 to 75 wt%.

In a further preferred embodiment, the binder is PVB (polyvinylpyrrolidone) and/or PVA (polyethylene glycol).

Further, the added amount of the binder is 1.5~5% of the total mass of slurry II and slurry III.

In a further preferred solution, the spray drying method is centrifugal spray drying, the nozzle rotation speed is 7000~15000rpm, the inlet air temperature is 150~250°C, and the air outlet temperature is 50~100°C.

In a further preferred embodiment, the molding method is cold isostatic pressing molding.

In a further preferred embodiment, the sintering is normal pressure sintering, and the sintering temperature is 1200~1450°C.

Further, the sintering time is 7~20h.

The advantages of the invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of specific embodiments of the invention.

Description of the drawings

Figure 1 is an SEM image of the pellets obtained in Example 1.

Figure 2 is a photograph of the cylindrical target obtained in Example 1.

Detailed ways

The invention first provides an oxide target material, in which the content of zinc oxide is 25~30wt%, the content of titanium oxide is 25~30wt%, the content of aluminum oxide is 5~12.5wt%, and the balance is indium tin oxide. .

Zinc, titanium, and aluminum oxides are all excellent n-type doped semiconductor materials. ZnO has outstanding advantages such as low price, non-toxicity, and easy preparation. Therefore, the ZnO doping system is considered to be the best substitute for ITO films. . The radius of Ti ⁴⁺ (0.064nm) and the radius of A1 ³⁺ (0.054nm) are smaller than the radius of In ³⁺ (0.08nm). They easily occupy the position of In ³⁺ and become substitution ions, and they also easily exist as interstitial ions. And the ion valence is greater than In ³⁺ . When Ti ⁴⁺ and A1 ³⁺ replace In ³⁺ in the crystal lattice, they can supply more abundant free electrons, increase the carrier concentration of the film, effectively reduce the resistivity, thereby improving the film conductive properties.

The inventor found that the resistivity of the target can be effectively reduced only by adding titanium oxide, zinc oxide and aluminum oxide to the ITO target (indium tin oxide) at the same time. Moreover, the addition of Zn, Ti, and Al oxides can reduce the amount of indium used in the target and save production costs.

In some preferred embodiments of the present invention, the outer diameter of the oxide target material is 180 to 210 mm. The outer diameter of traditional ITO targets is generally 150~160mm, which is small, and the target utilization rate is only about 60~75%. The present invention provides large-sized target materials, and the utilization rate can reach more than 85%.

In some preferred embodiments of the present invention, the resistivity of the oxide target material is 2.7×10 ^-5 ~3.2×10 ⁵ Ω·m.

Secondly, the present invention provides a method for preparing the above-mentioned oxide target, which includes the following steps:

Add zinc oxide, titanium oxide, and aluminum oxide powder to pure water and disperse to obtain slurry I;

Emulsify slurry I and then ball mill to obtain slurry II;

Add indium tin oxide powder to water and disperse to obtain slurry III;

Emulsify slurry III, then mix it with slurry II and binder, and ball-mill to obtain ball abrasive;

Spray dry the ball abrasive and then granulate to obtain pellets;

After the pellets are formed, they are sintered.

The dispersion described in the above preparation method can be dispersed using a dispersant, stirred and dispersed, or a combination of the two.

In some preferred embodiments of the present invention, the solid content of the slurry I is 25 to 50 wt%.

In some preferred embodiments of the present invention, the particle size D50 of the slurry II is 0.3~1 μm.

In some preferred embodiments of the present invention, the solid content of the slurry III is 25 to 50 wt%.

In some preferred embodiments of the present invention, the particle size D50 of the ball abrasive is 0.3~1 μm. The particle size of the ball abrasive is within this range, and the raw materials are mixed together very uniformly; at the same time, during sintering, due to the small particles, the sintering reaction can be completed faster.

In some preferred embodiments of the present invention, the solid content of the ball abrasive is 35 to 75 wt%.

The adhesive can be any adhesive commonly used in this field. In some preferred embodiments of the present invention, the binder is PVB (polyvinylpyrrolidone) and/or PVA (polyethylene glycol). Further, the added amount of the binder is 1.5~5% of the total mass of slurry II and slurry III. Adding a larger amount of binder during the ball milling process is conducive to preparing large-sized targets, and enhances the strength of the target, making target cracking less likely to occur.

In some preferred embodiments of the present invention, the spray drying method is centrifugal spray drying. Spray drying is instant drying, and further using centrifugal spray drying, the granulation is more rounded, with fewer broken balls, and the filler is more uniform during molding. After further optimization, the nozzle speed is controlled to 7000~15000rpm, the inlet air temperature is 150~250℃, and the outlet air temperature is 50~100℃.

In some preferred embodiments of the present invention, the molding method is cold isostatic pressing molding.

In some preferred embodiments of the present invention, the sintering is normal pressure sintering, and the sintering temperature is 1200~1450°C. Zinc oxide and titanium oxide are more likely to become liquid phase at high temperatures, lowering the sintering temperature of ITO. In addition, if the sintering temperature is too low, there will be many gaps between the particles of the target material during sintering, which will affect the density. If the temperature is too high, the grain size will easily grow and the target will crack. The sintering time can be adjusted adaptively. In the specific embodiment of the present invention, the sintering time is 7 to 20 hours.

In order to facilitate understanding of the present invention, the present invention will be described more comprehensively and in detail below with reference to the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

Unless otherwise defined, all technical terms used below have the same meanings as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of the present invention.

Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased in the market or prepared by existing methods.

Example 1

Add 25 parts by mass of zinc oxide, 30 parts by mass of titanium oxide and 5 parts by mass of aluminum oxide to 150 parts by mass of water, and disperse at 500 rpm for 0.5 h to obtain slurry I.

Stir and emulsify the dispersed slurry I at a stirring speed of 500 rpm, then add it to the ball mill and ball mill for 0.5 h to obtain slurry II with a particle size D50 of 0.5 μm.

Add 40 parts by mass of indium tin oxide to 100 parts by mass of pure water, and disperse at 700 rpm for 1 hour to obtain slurry III.

Stir and emulsify slurry III at a stirring speed of 500 rpm, and then put it into a ball mill together with slurry II for ball milling. During the ball milling process, add 7 parts by mass of PVA and 3 parts by mass of PVB. The ball milling speed is 700rpm and the ball milling time is After 3 hours, ball abrasive with a particle size of 0.3 μm was obtained.

Spray and granulate the ball-milled slurry at an inlet air temperature of 150°C, an outlet air temperature of 50°C and a spray speed of 7000rpm, and use a mixer to mix the materials at 5rpm/min for 10min.

Using a rigid mold, the powder is pressed into a cylindrical target embryo with a size of 180mm at 200MPa.

The pressed target embryo was sintered at a sintering temperature of 1200°C and a sintering time of 20 hours. After sintering is completed, the doped ITO target is obtained.

Figure 1 is an SEM image of the powder after spray granulation. It can be seen from the figure that spherical particles are obtained after spray granulation and have a hollow structure.

Figure 2 shows the cylindrical target material obtained by sintering. It can be seen that the target material has high density.

Comparative example 1

The only difference between Comparative Example 1 and Example 1 is that slurry I does not contain titanium oxide and aluminum oxide.

Comparative example 2

The only difference between Comparative Example 2 and Example 1 is that slurry I does not contain zinc oxide.

Comparative example 3

The only difference between Comparative Example 3 and Example 1 is that slurry I does not contain titanium oxide.

Comparative example 4

The only difference between Comparative Example 4 and Example 1 is that slurry I does not contain alumina.

Comparative example 5

The only difference between Comparative Example 5 and Example 1 is that the added amounts of zinc oxide, titanium oxide, and aluminum oxide are 35 parts by mass, 35 parts by mass, and 15 parts by mass respectively.

Comparative example 6

The only difference between Comparative Example 6 and Example 1 is that the added amounts of zinc oxide, titanium oxide, and aluminum oxide are 20 parts by mass, 20 parts by mass, and 4 parts by mass respectively.

Example 2

Add 30 parts by mass of zinc oxide, 25 parts by mass of titanium oxide and 12.5 parts by mass of alumina to 67.5 parts by mass of water, and disperse at 500 rpm for 0.5 h to obtain slurry I.

Stir and emulsify the dispersed slurry I at a stirring speed of 1000 rpm, then add it to the ball mill and ball mill for 2.5 hours to obtain slurry II with a particle size of 0.3 μm.

Add 32.5 parts by mass of indium tin oxide to 32.5 parts by mass of pure water, and disperse at 1200 rpm for 1 hour to obtain slurry III.

Stir and emulsify slurry III at a stirring speed of 1000 rpm, and then put it into a ball mill together with slurry II for ball milling. Add 3 parts by mass of PVA during the ball milling process to control the solid content of the slurry to 50wt% and the ball milling speed to 700rpm. , the ball milling time is 3h, and the ball abrasive with a particle size D50 of 0.5 μm is obtained.

Spray and granulate the ball-milled slurry at an inlet air temperature of 200°C, an outlet air temperature of 70°C, and a spray speed of 10,000 rpm. Use a mixer to mix the powder at 13 rpm/min for 50 minutes.

Using a rigid mold, the powder is pressed into a cylindrical target embryo with a size of 195mm at 300MPa.

The pressed target embryo was sintered at a sintering temperature of 1350°C and a sintering time of 12 hours. After sintering is completed, the doped ITO target is obtained.

Example 3

Add 28 parts by mass of zinc oxide, 28 parts by mass of titanium oxide and 10 parts by mass of alumina to 100 parts by mass of water, and disperse at 500 rpm for 0.5 h to obtain slurry I.

Stir and emulsify the dispersed slurry I at a stirring speed of 1500 rpm, then add it to the ball mill and ball mill for 1 hour to obtain slurry II with a particle size of 1 μm.

Add 34 parts by mass of indium tin oxide to 50 parts by mass of pure water, and disperse at 1500 rpm for 1 hour to obtain slurry III.

Stir and emulsify slurry III at a stirring speed of 1500 rpm, and then put it into a ball mill together with slurry II for ball milling. During the ball milling process, 12.5 parts by mass of PVB are added. The ball milling speed is 700rpm and the ball milling time is 2h. The obtained particle size is: 1μm ball abrasive.

The ball-milled slurry was spray-granulated at an inlet air temperature of 250°C, an outlet air temperature of 100°C, and a spray speed of 15,000 rpm. The powder was mixed using a mixer at 30 rpm/min for 100 min.

Using a rigid mold, the powder is pressed into a cylindrical target embryo with a size of 210mm at 400MPa.

The pressed target embryo was sintered at a sintering temperature of 1450°C and a sintering time of 7 hours. After sintering is completed, the doped ITO target is obtained.

The resistivity of the ITO targets obtained in Examples 1-3 and Comparative Examples 1-6 was tested in accordance with the national standard GB/T-351-2019.

The results are shown in Table 1.

Table 1

As can be seen from Table 1, compared to ITO containing only zinc oxide, titanium oxide or aluminum oxide, or compared to both containing zinc oxide, titanium oxide and aluminum oxide, ITO containing both zinc oxide, titanium oxide and aluminum oxide The resistivity of the target material is lower, and when the contents of zinc oxide, titanium oxide, and aluminum oxide are not within the range limited by the present invention, the resistivity of the target material increases.

The above are only the preferred embodiments of the present invention. It should be pointed out that those of ordinary skill in the art can also make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications can also be made. should be regarded as the protection scope of the present invention.

Claims (10)

1. An oxide target material, characterized in that the content of zinc oxide in the target material is 25~30wt%, the content of titanium oxide is 25~30wt%, the content of aluminum oxide is 5~12.5wt%, and the balance is Indium tin oxide. 2. The oxide target material according to claim 1, wherein the outer diameter of the target material is 180~210 mm. 3. The oxide target material according to claim 1 or 2, characterized in that the resistivity of the target material is 2.7×10 ^-5 ~ 3.2×10 ^-5 Ω·m. 4. The preparation method of the oxide target material according to any one of claims 1-3, characterized in that it includes the following steps: Add zinc oxide, titanium oxide, and aluminum oxide powder to pure water and disperse to obtain slurry I; Emulsify slurry I and then ball mill to obtain slurry II; Add indium tin oxide powder to water and disperse to obtain slurry III; Emulsify slurry III, then mix it with slurry II and binder, and ball-mill to obtain ball abrasive; Spray dry the ball abrasive and then granulate to obtain pellets; After the pellets are formed, they are sintered. 5. The preparation method according to claim 4, characterized in that the solid content of the slurry I is 25~50wt%; the solid content of the slurry III is 25~50wt%. 6. The preparation method according to claim 4, characterized in that the particle size D50 of the slurry II is 0.3~1 μm; the particle size D50 of the ball abrasive is 0.3~1 μm. 7. The preparation method according to any one of claims 4 to 6, characterized in that the binder is PVB and/or PVA; the added amount of the binder is slurry II and slurry III. 1.5~5% of the total mass. 8. The preparation method according to any one of claims 4 to 6, characterized in that the spray drying method is centrifugal spray drying, the nozzle rotation speed is 7000~15000rpm, the air inlet temperature is 150~250°C, and the air outlet temperature is 50~100℃. 9. The preparation method according to any one of claims 4 to 6, characterized in that the molding method is cold isostatic pressing. 10. The preparation method according to any one of claims 4 to 6, characterized in that the sintering is atmospheric pressure sintering, and the sintering temperature is 1200~1450°C.