阅读说明：本技术 一种ito陶瓷靶材的制备方法 (Preparation method of ITO ceramic target material ) 是由 王永超 赵泽良 贾时君 尤青文 于 2021-09-23 设计创作，主要内容包括：本发明提供了一种ITO陶瓷靶材的制备方法,包括以下步骤：将纯度为99.99%的In-(2)O-(3)粉末和SnO-(2)粉末按质量比为(90～97):(10～3)进行湿法球磨混合,球磨过程加入少量有机添加剂,得到流动性能良好的ITO浆料；将所得的ITO浆料进行喷雾造粒,得到的球形状ITO造粒粉；将所得的ITO造粒粉进行模压成型得到形状规则的ITO素坯；之后ITO素坯进行冷等静压二次压制；将冷等静压后的ITO素坯低温脱脂去除有机添加剂；将脱脂后的ITO素坯进行热等静压烧结制备出高致密度、低电阻率的ITO靶材。热等静压处理过程中选用低碳钢作为包套,不锈钢作为隔离材料,以防包套与靶材反应,便于后期剥离。本发明有效地降低了制备ITO靶材过程中所需的烧结温度及烧结时间,解决了传统常压烧结工艺生产周期过长的问题,对于提高靶材生产效率起着至关重要的意义。(The invention provides a preparation method of an ITO ceramic target material, which comprises the following steps: in with a purity of 99.99% 2 O 3 Powder and SnO 2 Carrying out wet ball milling mixing on the powder according to the mass ratio of (90-97) to (10-3), and adding a small amount of organic additive in the ball milling process to obtain ITO slurry with good flowing property; the obtained ITO slurry was subjected to spray granulation to obtain a spherical shapeGranulating ITO powder; carrying out compression molding on the obtained ITO granulation powder to obtain an ITO biscuit with a regular shape; then carrying out cold isostatic pressing on the ITO biscuit for secondary pressing; degreasing the ITO biscuit subjected to cold isostatic pressing at low temperature to remove organic additives; and carrying out hot isostatic pressing sintering on the degreased ITO biscuit to prepare the ITO target material with high density and low resistivity. In the hot isostatic pressing treatment process, low-carbon steel is used as a sheath, and stainless steel is used as an isolation material to prevent the sheath from reacting with the target material, so that later-stage stripping is facilitated. The invention effectively reduces the sintering temperature and the sintering time required in the process of preparing the ITO target material, solves the problem of overlong production period of the traditional normal-pressure sintering process, and plays a vital role in improving the production efficiency of the target material.)

1. The preparation method of the ITO ceramic target is characterized by comprising the following specific operation steps:

(1) in is mixed with₂O₃Powder and SnO₂Performing wet ball milling and mixing on the powder to obtain ITO slurry with good flowing property;

(2) carrying out spray granulation on the ITO slurry obtained in the step (1) to obtain spherical ITO granulation powder;

(3) carrying out compression molding on the ITO granulated powder obtained in the step (2) to obtain an ITO biscuit with a regular shape;

(4) carrying out cold isostatic pressing on the ITO biscuit obtained in the step (3);

(5) degreasing and sintering the ITO biscuit obtained in the step (4) to remove organic additives;

(6) and (5) carrying out hot isostatic pressing sintering on the ITO biscuit obtained in the step (5) to prepare the high-quality ITO target.

2. The production method according to claim 1, wherein In the step (1)₂O₃Raw powder and SnO₂The purity of the raw material powder is 99.99 percent; in₂O₃The average particle diameter of the raw material powder is 60-120 nm, and SnO₂The average particle diameter of the raw material powder is 100 to 200 nm.

3. The production method according to claim 1, wherein In the step (1)₂O₃: SnO₂The mass ratio is 90:10, 93:7, 95:5 and 97: 3.

4. The production method according to claim 1, wherein In the step (1)₂O₃Powder and SnO₂The powder is subjected to wet ball milling mixing, and the process comprises the following steps:

in₂O₃Raw powder and SnO₂Deionized water and 0.2-0.6 wt% of polyacrylic acid dispersant are added into the raw material powder, ball milling is carried out for 24-36 h, and the ball milling speed is 180-250 r/min. After uniformly mixing the powder, adding 0.2-0.6 wt% of binder, and continuously ball-milling for 15-30 min to obtain ITO slurry which is vacuumized and provided with air bubbles。

5. The preparation method according to claim 1, wherein the ITO slurry obtained in the step (1) has a solid content of 40-70 wt% and a viscosity of 70-150 mPa-S (25 ℃ at a rotation speed of 3.96S)^-1）。

6. The method according to claim 1, wherein in the step (2), the ITO slurry is spray-granulated to obtain a spherical granulated powder having good fluidity, and the average particle diameter D of the granulated powder is₅₀Is 7 to 13 μm.

7. The preparation method according to claim 1, wherein in the step (3), during the compression molding process, the compression molding pressure is 50-100 MPa, and the dwell time is 4-8 min, so that the ITO biscuit with the density of 30-45% is obtained.

8. The preparation method according to claim 1, wherein in the step (4), the density of the ITO green body is further improved to 45-65% in the cold isostatic pressing process under the pressure of 150-250 MPa for 20-50 min.

9. The preparation method according to claim 1, wherein in the step (5), the ITO green body is subjected to degreasing sintering, a small amount of dispersing agent and binder added in the ball milling process are removed, and the phenomenon that the capsule bulges due to gas generated by decomposition and volatilization of organic matters in the subsequent hot isostatic pressing sintering process is avoided. The degreasing temperature is 600-800 ℃, and the degreasing time is 8-12 h.

10. The production method according to claim 1, wherein in the step (6), the degreased ITO green compact is subjected to hot isostatic pressing sintering at a sintering temperature of 950 to 1150 ℃, a holding pressure of 120 to 180 MPa, and a holding time of 2 to 5 hours.

11. The method according to claim 1, wherein in step (6), the jacket material is low-carbon steel, the isolating material is 304 stainless steel, and the jacket is evacuated before sealing. The sheath welding adopts an argon arc welding mode.

Technical Field

The invention relates to the field of advanced ceramic target preparation, in particular to a preparation method of an ITO ceramic target.

Background

The ITO film is a heavily doped and highly degenerated n-type semiconductor material, and has good light transmission and conductivity (visible light transmittance is higher than 95 percent, and resistivity is 10 percent)^-4Omega cm magnitude), excellent wear resistance, corrosion resistance, high thermal stability, good chemical etching property and the like, is widely applied to the fields of control panels (TPs), Organic Light Emitting Diodes (OLED), solar cells, antistatic glass and the like, and is an advanced material with a far great application prospect.

The performance of the ITO film is closely related to the comprehensive quality of the ITO target, and the high-quality ITO ceramic target is prepared from the ITO film with excellent performance.

At present, ITO biscuit forming modes are mainly divided into two types (1) of wet forming; (2) and (4) dry forming. The wet forming is generally grouting forming, and although the forming mode has the characteristics of simplicity in operation, low production cost and the like, the blank body needs to be dried in a specific environment for a long time at the later stage, the production period is too long, and the problems of product backlog, too high inventory and the like can be caused for enterprises producing targets in large quantities. The forming mode of the invention belongs to dry forming, and a drying link is not needed, so that the production period of the target forming stage is greatly shortened.

At present, the ITO target material sintering modes mainly comprise three (1) normal-pressure atmosphere sintering; (2) hot pressing and sintering; (3) and (4) hot isostatic pressing sintering.

The normal pressure atmosphere sintering refers to a sintering process for realizing densification by heating an ITO biscuit to a certain temperature under the condition of oxygen atmosphere and preserving heat for a certain time, and the furnace is not pressurized. The sintering process has high requirements on the sintering activity of the ITO powder, high sintering temperature (higher than 1500 ℃), long sintering period and large difficulty of sintering technology, and the performance of the target material is reduced along with the increase of the density of the target material in the later sintering period. In the invention patent publication No. CN108947520A, an ITO biscuit is placed in a normal pressure atmosphere sintering furnace, high-purity oxygen is introduced, the sintering temperature is 1550-1600 ℃, and the sintering time is 5-10 h.

The hot press sintering is a sintering method in which ITO powder is loaded into a special mold, and an ITO green compact is molded and sintered simultaneously by heating and pressurizing. The sintering process has the defects that the pressure distribution is not uniform, so that the internal density of the target material is not uniform, and the large-size target material cannot be prepared. The invention provides a method for preparing an ITO sputtering target material by hot-pressing sintering, wherein a special graphite die is adopted in the hot-pressing process, graphite is easy to react with ITO powder at high temperature, hot-pressing pressure is applied in a single direction, and the prepared ITO target material has uneven density.

The hot isostatic pressing sintering can solve the problems in the sintering process, not only can uniformly apply force to the ITO green body in all directions in the heating process, but also can further reduce the sintering temperature and the sintering time, shorten the production period, is suitable for mass production, and has a vital significance for improving the production efficiency of the ITO target.

Patent document

A preparation method of an ITO sintered target material, CN108947520A [ P ] 2018.

Hubai DC, Subenshuang, Liuxiaoling, etc. the preparation method of ITO sputtering target material, CN101575203[ P ] 2009.

Disclosure of Invention

The problems of long production period, low production efficiency and the like in the prior art are solved. The invention provides a preparation method of an ITO ceramic target, which further improves the production efficiency of target preparation from molding to sintering, and comprises the following steps:

(1) in is mixed with₂O₃Powder ofAnd SnO₂Performing wet ball milling and mixing on the powder to obtain ITO slurry with good flowing property;

(2) carrying out spray granulation on the ITO slurry obtained in the step (1) to obtain spherical ITO granulation powder;

(3) carrying out compression molding on the ITO granulated powder obtained in the step (2) to obtain an ITO biscuit with a regular shape;

(4) carrying out cold isostatic pressing on the ITO biscuit obtained in the step (3);

(5) degreasing and sintering the ITO biscuit obtained in the step (4) to remove organic additives;

(6) and (5) carrying out hot isostatic pressing sintering on the ITO biscuit obtained in the step (5) to prepare the high-quality ITO target.

Further, In the step (1), In₂O₃Raw powder and SnO₂The purity of the raw material powder is 99.99 percent; in₂O₃The average particle diameter of the raw material powder is 60-120 nm, and SnO₂The average particle diameter of the raw material powder is 100 to 200 nm.

Further, In the step (1), In₂O₃: SnO₂The mass ratio is 90:10, 93:7, 95:5 and 97: 3.

Further, In the step (1), In₂O₃Powder and SnO₂The powder is subjected to wet ball milling mixing, and the process comprises the following steps:

in₂O₃Raw powder and SnO₂Deionized water and 0.2-0.6 wt% of polyacrylic acid dispersant are added into the raw material powder, ball milling is carried out for 24-36 h, and the ball milling speed is 180-250 r/min. And (3) uniformly mixing the powder, adding 0.2-0.6 wt% of a binder, and continuously performing ball milling for 15-30 min to obtain ITO slurry, and vacuumizing to remove bubbles.

Further, the ITO slurry obtained in the step (1) has a solid content of 40-70 wt% and a viscosity of 70-150 mPa & S (25 ℃, rotating speed of 3.96S)^-1）。

Further, in the step (2), the ITO slurry is subjected to spray granulation to obtain spherical granulated powder with good flowing property, and the average particle size D of the granulated powder₅₀Is 7～13 μm。

Further, in the step (3), in the compression molding process, the mold pressing pressure is 50-100 MPa, and the pressure maintaining time is 4-8 min, so that an ITO biscuit with the density of 30-45% is obtained;

further, in the step (4), in the cold isostatic pressing process, the pressure maintaining pressure is 150-250 MPa, the pressure maintaining time is 20-50 min, and the density of the ITO biscuit is further improved to 45-65%;

further, in the step (5), the ITO biscuit is subjected to degreasing sintering, a small amount of dispersing agent and binder added in the ball milling process are removed, and the phenomenon that the wrapping bag bulges caused by gas generated by decomposition and volatilization of organic matters in the subsequent hot isostatic pressing sintering process is avoided. The degreasing temperature is 600-800 ℃, and the degreasing time is 8-12 h.

Further, in the step (6), the degreased ITO biscuit is subjected to hot isostatic pressing sintering, wherein the sintering temperature is 950-1150 ℃, the pressure maintaining pressure is 120-180 MPa, and the pressure maintaining time is 2-5 h.

Further, in the step (6), in the hot isostatic pressing treatment process, the jacket material is low-carbon steel, the isolation material is 304 stainless steel, and before the jacket is sealed, vacuumizing and exhausting are performed.

Further, in the step (6), the sheath welding adopts an argon arc welding mode.

Further, the density of the prepared ITO target is higher than 99.3%, and the resistivity is 1.6-2.0 multiplied by 10^-4 mΩ·cm。

Compared with the prior art, the invention has the following advantages:

spherical ITO granulating powder with good flowing property is obtained through spray granulation, and the density of an ITO green body in the process of compression molding is improved.

By the die pressing and Cold Isostatic Pressing (CIP) secondary pressing forming process, the density of the ITO biscuit is maximized, and the shrinkage of the package in the HIP link can be reduced. Meanwhile, compared with the traditional slip casting, the method does not need an overlong drying process, further shortens the time required by blank forming, and improves the production efficiency.

By a Hot Isostatic Pressing (HIP) sintering process, the ITO biscuit is uniformly stressed in the sintering process, and the problems of uneven target material density, cracking deformation and the like are avoided. Meanwhile, high-purity oxygen is not needed to participate in the traditional normal-pressure oxygen sintering, the temperature and time required by sintering are further reduced, the preparation period of the target material is shortened, and the production cost is reduced. The invention is suitable for industrial production.

Drawings

FIG. 1 is a process flow diagram of the ITO target preparation method of the present invention.

Detailed Description

The invention will be further illustrated with reference to specific examples, but is not limited to the examples given.

Example 1

Weighing In₂O₃: SnO₂Adding pure water, polyacrylic acid dispersing agent and binder into raw material powder with a mass ratio of 90:10 according to requirements, and performing ball milling and mixing to prepare ITO slurry with a solid content of 50%;

carrying out spray granulation on the ITO slurry to obtain the average particle diameter D₅₀Is 10 μm spherical granulation powder;

filling the ITO granulation powder into a special mould pressing die for forming, wherein the mould pressing pressure is 60 MPa, and the pressure maintaining time is 5 min, so as to obtain an ITO biscuit with the density of 38%;

carrying out cold isostatic pressing on the ITO biscuit, keeping the pressure at 200 MPa for 30 min, and obtaining the ITO biscuit with the density of 60%;

degreasing the ITO biscuit for 10 hours at the temperature of 800 ℃;

filling the degreased ITO biscuit into a low-carbon steel ladle sleeve, adding a 304 stainless steel isolation material between the sheath and the ITO biscuit, and performing hot isostatic pressing sintering, wherein the hot isostatic pressing temperature is 1150 ℃, the pressure maintaining pressure is 150 MPa, and the pressure maintaining time is 3 h;

after hot isostatic pressing sintering, the density is 99.5 percent, the resistivity is 1.6 multiplied by 10^-4An ITO target material of m omega cm. In the process of stripping the target material from the sheath, the isolation material does not react with the target material, the target material is in a perfect shape, and the target material does not crack.

Example 2

Weighing In₂O₃: SnO₂Adding pure water into raw material powder with the mass ratio of 90:10 according to the requirementMixing the polyacrylic acid dispersing agent and the binder by ball milling to prepare ITO slurry with the solid content of 50%;

carrying out spray granulation on the ITO slurry to obtain the average particle diameter D₅₀Is 10 μm spherical granulation powder;

filling the ITO granulation powder into a special mould pressing die for forming, wherein the mould pressing pressure is 60 MPa, and the pressure maintaining time is 5 min, so as to obtain an ITO biscuit with the density of 38%;

carrying out cold isostatic pressing on the ITO biscuit, keeping the pressure at 200 MPa for 30 min, and obtaining the ITO biscuit with the density of 60%;

degreasing the ITO biscuit for 10 hours at the temperature of 800 ℃;

filling the degreased ITO biscuit into a low-carbon steel ladle sleeve, adding a 304 stainless steel isolation material between the sheath and the ITO biscuit, and performing hot isostatic pressing sintering, wherein the hot isostatic pressing temperature is 1050 ℃, the pressure maintaining pressure is 150 MPa, and the pressure maintaining time is 3 h;

after hot isostatic pressing sintering, the density is 98.5%, and the resistivity is 1.8 multiplied by 10^-4An ITO target material of m omega cm. In the process of stripping the target material from the sheath, the isolation material does not react with the target material, the target material is in a perfect shape, and the target material does not crack.

Example 3

Weighing In₂O₃: SnO₂Adding pure water, polyacrylic acid dispersing agent and binder into raw material powder with a mass ratio of 90:10 according to requirements, and performing ball milling and mixing to prepare ITO slurry with a solid content of 50%;

carrying out spray granulation on the ITO slurry to obtain the average particle diameter D₅₀Is 10 μm spherical granulation powder;

filling the ITO granulation powder into a special mould pressing die for forming, wherein the mould pressing pressure is 60 MPa, and the pressure maintaining time is 5 min, so as to obtain an ITO biscuit with the density of 38%;

carrying out cold isostatic pressing on the ITO biscuit, keeping the pressure at 200 MPa for 30 min, and obtaining the ITO biscuit with the density of 60%;

degreasing the ITO biscuit for 10 hours at the temperature of 800 ℃;

filling the degreased ITO biscuit into a low-carbon steel ladle sleeve, adding a 304 stainless steel isolation material between the sheath and the ITO biscuit, and performing hot isostatic pressing sintering, wherein the hot isostatic pressing temperature is 1150 ℃, the pressure maintaining pressure is 120 MPa, and the pressure maintaining time is 3 h;

after hot isostatic pressing sintering, the density is 99.0 percent, and the resistivity is 1.7 multiplied by 10^-4An ITO target material of m omega cm. In the process of stripping the target material from the sheath, the isolation material does not react with the target material, the target material is in a perfect shape, and the target material does not crack.

Example 4

Weighing In₂O₃: SnO₂Adding pure water, polyacrylic acid dispersing agent and binder into raw material powder with a mass ratio of 90:10 according to requirements, and performing ball milling and mixing to prepare ITO slurry with a solid content of 50%;

carrying out spray granulation on the ITO slurry to obtain the average particle diameter D₅₀Is 10 μm spherical granulation powder;

filling the ITO granulation powder into a special mould pressing die for forming, wherein the mould pressing pressure is 60 MPa, and the pressure maintaining time is 5 min, so as to obtain an ITO biscuit with the density of 38%;

carrying out cold isostatic pressing on the ITO biscuit, keeping the pressure at 200 MPa for 30 min, and obtaining the ITO biscuit with the density of 60%;

degreasing the ITO biscuit for 10 hours at the temperature of 800 ℃;

filling the degreased ITO biscuit into a low-carbon steel ladle sleeve, adding a 304 stainless steel isolation material between the sheath and the ITO biscuit, and performing hot isostatic pressing sintering, wherein the hot isostatic pressing temperature is 1150 ℃, the pressure maintaining pressure is 150 MPa, and the pressure maintaining time is 5 h;

after hot isostatic pressing sintering, the density is 99.1%, and the resistivity is 1.8 multiplied by 10^-4An ITO target material of m omega cm. In the process of stripping the target material from the sheath, the isolation material does not react with the target material, the target material is in a perfect shape, and the target material does not crack.

Comparative example 1

Weighing In₂O₃: SnO₂Adding pure water, polyacrylic acid dispersing agent and binder into raw material powder with a mass ratio of 90:10 according to requirements, and performing ball milling and mixing to prepare ITO slurry with a solid content of 50%;

carrying out spray granulation on the ITO slurry to obtain the average particle diameter D₅₀Is 10 μm spherical granulation powder;

filling the ITO granulation powder into a special mould pressing die for forming, wherein the mould pressing pressure is 60 MPa, and the pressure maintaining time is 5 min, so as to obtain an ITO biscuit with the density of 38%;

carrying out cold isostatic pressing on the ITO biscuit, keeping the pressure at 200 MPa for 30 min, and obtaining the ITO biscuit with the density of 60%;

degreasing the ITO biscuit for 10 hours at the temperature of 800 ℃;

carrying out atmospheric pressure oxygen sintering on the degreased ITO biscuit, wherein the sintering temperature is 1600 ℃, and the heat preservation time is 10 h;

the density of the obtained product is 98.8 percent and the resistivity is 1.8 multiplied by 10 after atmospheric pressure oxygen sintering^-4An ITO target material of m omega cm.

Comparative example 2

Weighing In₂O₃: SnO₂Adding pure water, polyacrylic acid dispersing agent and binder into raw material powder with a mass ratio of 90:10 according to requirements, and performing ball milling and mixing to prepare ITO slurry with a solid content of 50%;

carrying out spray granulation on the ITO slurry to obtain the average particle diameter D₅₀Is 10 μm spherical granulation powder;

filling the ITO granulation powder into a special mould pressing die for forming, wherein the mould pressing pressure is 60 MPa, and the pressure maintaining time is 5 min, so as to obtain an ITO biscuit with the density of 38%;

carrying out cold isostatic pressing on the ITO biscuit, keeping the pressure at 200 MPa for 30 min, and obtaining the ITO biscuit with the density of 60%;

degreasing the ITO biscuit for 10 hours at the temperature of 800 ℃;

carrying out atmospheric pressure oxygen sintering on the degreased ITO biscuit, wherein the sintering temperature is 1600 ℃, and the heat preservation time is 3 h;

the density is 96.2 percent and the resistivity is 2.3 multiplied by 10 after atmospheric pressure oxygen sintering^-4An ITO target material of m omega cm.

The above description is a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Modifications of the technical solutions of the above embodiments, or equivalent replacements of some technical features thereof according to the substance of the present invention, are all included in the protection scope of the present invention.