阅读说明：本技术 一种钼钨溅射靶材及其制备方法 (Molybdenum-tungsten sputtering target material and preparation method thereof ) 是由 陈金 李保强 刘文迪 黄志民 于 2020-07-17 设计创作，主要内容包括：本发明公开了一种钼钨溅射靶材及其制备方法,其相对密度为99.0-99.5％,氧含量为350-600ppm,原料由纯度≥4N的三氧化钨粉和纯度≥3N的钼粉组成,且三氧化钨粉的含量为15-20wt％,余量为钼粉,该三氧化钨粉的粒径为7-10μm,该钼粉的粒径为4.5-6.5μm。本发明适用于制备平面显示器,组织均匀,无孔洞,且氧含量低。(The invention discloses a molybdenum-tungsten sputtering target material and a preparation method thereof, wherein the relative density is 99.0-99.5%, the oxygen content is 350-600ppm, the raw material comprises tungsten trioxide powder with the purity of more than or equal to 4N and molybdenum powder with the purity of more than or equal to 3N, the content of the tungsten trioxide powder is 15-20 wt%, the balance is the molybdenum powder, the particle size of the tungsten trioxide powder is 7-10 mu m, and the particle size of the molybdenum powder is 4.5-6.5 mu m. The invention is suitable for preparing flat panel display, has uniform structure, no holes and low oxygen content.)

1. A molybdenum-tungsten sputtering target material is characterized in that: the relative density of the tungsten trioxide powder is 99.0-99.5%, the oxygen content is 350-600ppm, the raw materials comprise tungsten trioxide powder with the purity of more than or equal to 4N and molybdenum powder with the purity of more than or equal to 3N, the content of the tungsten trioxide powder is 15-20 wt%, the balance is the molybdenum powder, the particle size of the tungsten trioxide powder is 7-10 mu m, and the particle size of the molybdenum powder is 4.5-6.5 mu m.

2. The method for preparing the molybdenum-tungsten sputtering target material according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:

(1) carrying out high-energy ball milling on the tungsten trioxide powder and the molybdenum powder in vacuum or inert gas atmosphere to uniformly mix the tungsten trioxide powder and the molybdenum powder to obtain mixed powder;

(2) putting the mixed powder into a molybdenum boat, and carrying out two-stage reduction in a hydrogen furnace to obtain molybdenum-tungsten mixed powder;

(3) carrying out cold isostatic pressing on the molybdenum-tungsten mixed powder to obtain a molybdenum-tungsten green body;

(4) carrying out vacuum sintering on the molybdenum-tungsten green body to obtain a semi-sintered body;

(5) and carrying out vacuum hot-pressing sintering and machining on the semi-sintered body to obtain the molybdenum-tungsten sputtering target.

3. The method of claim 2, wherein: the high-energy ball milling has the rotation speed of 110-120rpm, the time of 18-20h, the ball-material ratio of 6-10: 1, and the used milling ball is tungsten ball or molybdenum ball.

4. The method of claim 2, wherein: the inert gas atmosphere is argon atmosphere or helium atmosphere.

5. The method of claim 2, wherein: the thickness of the mixed powder in the molybdenum boat is 10-15 mm.

6. The method of claim 2, wherein: in the two-stage reduction, the first-stage reduction temperature is 460-480 ℃ and the time is 0.5-2h, and the second-stage reduction temperature is 910-920 ℃ and the time is 0.5-1.5 h.

7. The method of claim 2, wherein: the pressure of the cold isostatic pressing is 150-180MPa, and the pressure maintaining time is 20-30 min.

8. The method of claim 2, wherein: the temperature of the vacuum sintering is 1450-.

9. The method of claim 8, wherein: the vacuum degree of the vacuum sintering is 10^-3-10^-1Pa。

10. The method of claim 2, wherein: the temperature of the vacuum hot-pressing sintering is 1700-1800 ℃, and the vacuum degree is 10^-1-1Pa, 25-35MPa and 4-5h of dwell time.

Technical Field

The invention belongs to the technical field of powder metallurgy, and particularly relates to a molybdenum-tungsten sputtering target material and a preparation method thereof.

Background

Vacuum sputtering coating is a common film preparation process, and a target material is an important raw material for sputtering coating. During sputtering, argon ions are accelerated to impact the surface of the target under the action of an electric field, so that energy exchange is carried out between the argon ions and atoms on the surface of the target, target atoms with enough energy are obtained to escape from the surface of the target and deposit on the surface of a substrate, and a thin film is formed on the surface of the substrate.

The molybdenum-tungsten sputtering target is a target which is often used in the vacuum sputtering process, and the molybdenum-tungsten film obtained by sputtering is mainly used as a transparent conductive film or a metal wiring film and is applied to the preparation process of a flat panel display. The molybdenum-tungsten alloy has better conductivity and oxidation resistance and lower coating stress than molybdenum, can meet the performance requirement of a flat panel display coating production line on a sputtering target, and is particularly suitable for preparing a film layer in a high-quality flat panel display by using the molybdenum-tungsten alloy containing 3.5-25 wt.% of tungsten. In recent years, the market for flat panel displays, which focus on Liquid Crystal Displays (LCDs), has grown rapidly, increasing the demand for molybdenum tungsten sputtering targets. With the continuous development of the technology, the performance requirements on the molybdenum-tungsten film are higher and higher, which puts higher requirements on the compactness, the structural uniformity and the like of the molybdenum-tungsten sputtering target material.

Currently, the molybdenum-tungsten sputtering target is mainly prepared by a hot rolling process or a hot isostatic pressing process. CN103255379A discloses a method for preparing a molybdenum-tungsten alloy sputtering target for flat panel displays, which uses 80-96.5 wt.% molybdenum powder and 3.5-20 wt.% tungsten powder as raw materials, and is prepared by the processes of powder blending, mechanical alloying, cold isostatic pressing, sintering, hot rolling, etc. CN103320756A discloses a preparation method for preparing a large-size and high-performance molybdenum alloy target by using a hot isostatic pressing technology, namely, a molybdenum-tungsten sputtering target is prepared by taking molybdenum powder and tungsten powder as raw materials and carrying out the procedures of mixing, pressing, pre-reduction, hot isostatic pressing and the like. However, the crystal grains of the target material obtained through the hot rolling process generally have orientation, and are likely to cause unevenness in the thickness of the sputtered film; the introduction of hot isostatic pressing technology increases the complexity of the process while increasing the overall cost.

In addition, whether the raw material powder is mixed uniformly or not directly affects the tissue structure of the target material. Currently, molybdenum powder and tungsten powder are generally used as raw materials for preparing molybdenum-tungsten sputtering targets, and the molybdenum powder and the tungsten powder have large density difference, so that the phenomenon of structural layering or segregation is easy to occur, and the structural uniformity of the targets is influenced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a molybdenum-tungsten sputtering target material.

The invention also aims to provide a preparation method of the molybdenum-tungsten sputtering target material.

The technical scheme of the invention is as follows:

the molybdenum-tungsten sputtering target material has a relative density of 99.0-99.5% and an oxygen content of 350-600ppm, and is prepared from tungsten trioxide powder with a purity of 4N or more and molybdenum powder with a purity of 3N or more, wherein the tungsten trioxide powder content is 15-20 wt%, and the balance is molybdenum powder, the particle size of the tungsten trioxide powder is 7-10 μm, and the particle size of the molybdenum powder is 4.5-6.5 μm.

The preparation method of the molybdenum-tungsten sputtering target comprises the following steps:

(1) carrying out high-energy ball milling on the tungsten trioxide powder and the molybdenum powder in vacuum or inert gas atmosphere to uniformly mix the tungsten trioxide powder and the molybdenum powder to obtain mixed powder;

(2) putting the mixed powder into a molybdenum boat, and carrying out two-stage reduction in a hydrogen furnace to obtain molybdenum-tungsten mixed powder;

(3) carrying out cold isostatic pressing on the molybdenum-tungsten mixed powder to obtain a molybdenum-tungsten green body;

(4) carrying out vacuum sintering on the molybdenum-tungsten green body to obtain a semi-sintered body;

(5) and carrying out vacuum hot-pressing sintering and machining on the semi-sintered body to obtain the molybdenum-tungsten sputtering target.

In a preferred embodiment of the invention, the rotation speed of the high-energy ball mill is 110-120rpm, the time is 18-20h, the ball-to-material ratio is 6-10: 1, and the grinding balls are tungsten balls or molybdenum balls.

In a preferred embodiment of the present invention, the inert gas atmosphere is an argon atmosphere or a helium atmosphere.

In a preferred embodiment of the invention, the thickness of the mixed powder in the molybdenum boat is 10-15 mm.

In a preferred embodiment of the invention, in the two-stage reduction, the first-stage reduction temperature is 460-480 ℃ for 0.5-2h, and the second-stage reduction temperature is 910-920 ℃ for 0.5-1.5 h.

In a preferred embodiment of the invention, the pressure of the cold isostatic pressing is 150-180MPa, and the dwell time is 20-30 min.

In a preferred embodiment of the present invention, the temperature of the vacuum sintering is 1450-.

More preferably, the vacuum degree of the vacuum sintering is 10^-3-10^-1Pa。

In a preferred embodiment of the present invention, the temperature of the vacuum hot-pressing sintering is 1700-1800 ℃, and the vacuum degree is 10^-1-1Pa, 25-35MPa and 4-5h of dwell time.

The invention has the beneficial effects that:

1. the invention is suitable for preparing flat panel display, has uniform structure, no holes and low oxygen content.

2. According to the preparation method, the molybdenum powder and the tungsten trioxide powder serving as the precursor of tungsten are mixed, and the uniformly mixed powder is easier to obtain due to smaller density difference between the molybdenum powder and the tungsten trioxide powder; by H₂Carrying out high-temperature treatment twice under the atmosphere to realize in-situ reduction of the tungsten trioxide powder, thereby obtaining uniform molybdenum-tungsten mixed powder; this helps to improve the texture uniformity of the sintered target material, thereby achieving the optimal film coating effect.

3. The preparation method provided by the invention adopts a high-energy ball milling mode to mix the raw materials, and is beneficial to the refinement of the powder, so that the sintering activity of the powder is improved, and the acquisition of a high-compactness sintered blank is promoted.

4. According to the preparation method, before hot-pressing densification, powder is subjected to CIP forming and pre-sintering, which is beneficial to removing volatile non-metallic elements (such as oxygen) in the target blank, and meanwhile, the green blank is subjected to a primary densification process, so that secondary densification of the green blank is realized through hot-pressing sintering.

5. The preparation method of the invention has strong operability and low cost.

Drawings

FIG. 1 is a process flow diagram of an embodiment of the present invention.

Fig. 2 is a structural diagram of the molybdenum-tungsten target obtained in example 1 of the present invention.

FIG. 3 is a structural diagram of the molybdenum-tungsten target obtained in comparative example 2.

Detailed Description

The technical solution of the present invention will be further illustrated and described below with reference to the accompanying drawings by means of specific embodiments.

The process flow of examples 1 to 3 of the present invention is shown in FIG. 1.