阅读说明：本技术 一种钨硅靶材的制备方法 (Preparation method of tungsten-silicon target material ) 是由 李保强 祁美贵 刘文迪 李斌玲 郑艾龙 黄志民 于 2019-09-09 设计创作，主要内容包括：本发明涉及一种钨硅靶材的制备方法,以纯度≥6N的多晶硅粒代替硅粉为原料进行钨硅靶材的制备,克服了硅粉纯度偏低、高纯度硅粉成本高的问题；并且,基于多晶硅粒的纯度更容易得到保证的情况,原料更易获取,不仅能够保证制备的钨硅靶材的纯度,还能够降低生产成本。由于硅材料相对于钨材料更容易破碎,本发明以多晶硅粒为原料直接和钨粉进行混合破碎,在对多晶硅粒进行破碎的同时,可与钨粉进行充分混合,进而通过一个步骤即可得到钨硅混合料,提高生产效率。由于多晶硅粒的破碎与钨硅粉体的制备在一台设备(球磨机)上连续进行,避免了因工艺流程过长而对材料造成的污染,有助于保证材料的纯度；同时降低了生产成本。(The invention relates to a preparation method of a tungsten-silicon target, which is used for preparing the tungsten-silicon target by using polycrystalline silicon particles with the purity of more than or equal to 6N to replace silicon powder as a raw material, and solves the problems of low purity of the silicon powder and high cost of the high-purity silicon powder; and moreover, on the basis of the condition that the purity of polycrystalline silicon particles is easier to ensure, raw materials are easier to obtain, the purity of the prepared tungsten silicon target material can be ensured, and the production cost can be reduced. Because the silicon material is easier to crush than the tungsten material, the invention takes the polysilicon grains as the raw material to be directly mixed and crushed with the tungsten powder, and the polysilicon grains can be fully mixed with the tungsten powder while being crushed, so that the tungsten-silicon mixture can be obtained through one step, and the production efficiency is improved. Because the crushing of the polysilicon grains and the preparation of the tungsten-silicon powder are continuously carried out on one device (a ball mill), the pollution to the material caused by overlong process flow is avoided, and the purity of the material is favorably ensured; and meanwhile, the production cost is reduced.)

1. The preparation method of the tungsten silicon target is characterized by comprising the following steps:

1) weighing tungsten powder and polysilicon grains according to the mass fraction of the polysilicon grains of 23.41-37.93 wt.%; the Fisher average granularity of the tungsten powder is 1-10 mu m, the purity is more than or equal to 5N, the granularity of the polycrystalline silicon particles is 1-10mm, and the purity is more than or equal to 6N;

2) placing the tungsten powder and the polycrystalline silicon particles obtained in the step 1) into a ball milling tank, crushing the polycrystalline silicon particles at the rotating speed of 50-70rpm for ball milling time of 24-48h, and simultaneously uniformly mixing the two materials;

3) the rotating speed is increased to 200 and 300rpm, and ball milling is carried out for 30-100h to obtain tungsten silicon powder;

4) and (3) carrying out cold pressing, vacuum hot-pressing sintering and machining on the tungsten silicon powder obtained in the step 3) to obtain the tungsten silicon target.

2. The preparation method of the tungsten-silicon target material according to claim 1, wherein the purity of the tungsten-silicon target material obtained in the step 4) is not less than 4N5, and the relative density is not less than 99%.

3. The method for preparing a tungsten-silicon target material according to claim 1 or 2, wherein in the step 1), the tungsten powder and the polysilicon grains are weighed according to a proportion of 28.43-29.96 wt.% of the mass fraction of the polysilicon grains.

4. The method for preparing the tungsten-silicon target material according to claim 1 or 2, wherein the grinding balls used in the ball milling are made of the same material as tungsten powder or polysilicon particles, or are other hard alloy balls.

5. The method for preparing the tungsten-silicon target material according to claim 1 or 2, wherein the ball-to-material ratio during ball milling is 10:1-40: 1.

6. The method for preparing the tungsten-silicon target material according to claim 1 or 2, wherein in the step 2) and the step 3), a high-purity inert gas is filled in the ball-milling pot.

7. The method for preparing the tungsten-silicon target material according to claim 5, wherein the high-purity inert gas is high-purity argon or high-purity helium.

8. The tungsten silicon target material according to claim 1 or 2The preparation method is characterized in that in the step 4), the temperature of the vacuum hot-pressing sintering is 1200-1400 ℃, and the vacuum degree is 10^-1-1Pa, and the vacuum hot-pressing pressure is 20-50 MPa.

Technical Field

The invention relates to the technical field of semiconductor sputtering targets, in particular to a preparation method of a tungsten-silicon target.

Background

The sputtering coating belongs to the physical coating technology, is an important method for manufacturing a semiconductor film layer, and belongs to an important part which is indispensable in the semiconductor manufacturing. The sputtering coating is to form a high-energy ion beam by utilizing ions generated by an ion source and accelerating the ions by an electric field in vacuum so as to bombard the surface of a solid; kinetic energy exchange is carried out between the high-speed ions and atoms on the solid surface, so that the atoms on the solid surface break away from the solid surface; the sputtered atoms are deposited on the surface of the substrate, thereby achieving the purpose of sputtering coating.

The bombarded solid during sputtering coating is the target material, and the tungsten silicon target material is one kind of target material commonly used in the manufacture of semiconductor film. The film layer formed by sputtering the tungsten silicon target material is an excellent conductor and is widely applied to the field of electronic gate materials and electronic films. In order to make the film have better performance, the tungsten silicon target material is required to have higher purity and compactness, and has higher requirements on the microstructure uniformity and the grain size of the target material.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a tungsten silicon target material, which is used for preparing the tungsten silicon target material with high purity and high compactness and has lower cost.

The technical scheme of the invention is as follows:

a preparation method of a tungsten silicon target comprises the following steps:

1) weighing tungsten powder and polysilicon grains according to the mass fraction of the polysilicon grains of 23.41-37.93 wt.%; the Fisher average granularity of the tungsten powder is 1-10 mu m, the purity is more than or equal to 5N, the granularity of the polycrystalline silicon particles is 1-10mm, and the purity is more than or equal to 6N;

2) placing the tungsten powder and the polycrystalline silicon particles obtained in the step 1) into a ball milling tank, crushing the polycrystalline silicon particles at the rotating speed of 50-70rpm for ball milling time of 24-48h, and simultaneously uniformly mixing the two materials;

3) the rotating speed is increased to 200 and 300rpm, and ball milling is carried out for 30-100h to obtain tungsten silicon powder;

4) and (3) carrying out cold pressing, vacuum hot-pressing sintering and machining on the tungsten silicon powder obtained in the step 3) to obtain the tungsten silicon target.

Preferably, the purity of the tungsten-silicon target material obtained in the step 4) is more than or equal to 4N5, and the relative density is more than or equal to 99%.

Preferably, in the step 1), the tungsten powder and the polysilicon grains are weighed according to the mass fraction of the polysilicon grains of 28.43-29.96 wt.%.

Preferably, the grinding balls used in the ball milling are made of the same material as the tungsten powder or the polycrystalline silicon particles, or are made of other hard alloy balls.

Preferably, the ball-to-material ratio during ball milling is 10:1 to 40: 1.

Preferably, in the step 2) and the step 3), the ball mill pot is filled with a high-purity inert gas.

Preferably, the high-purity inert gas is high-purity argon or high-purity helium.

Preferably, in the step 4), the temperature of the vacuum hot-pressing sintering is 1200-1400 ℃, and the vacuum degree is 10^-1-1Pa, and the vacuum hot-pressing pressure is 20-50 MPa.

The invention has the following beneficial effects:

according to the preparation method of the tungsten-silicon target material, polycrystalline silicon particles with the purity of more than or equal to 6N are used for replacing silicon powder as a raw material to prepare the tungsten-silicon target material, so that the problems of low purity of the silicon powder and high cost of the high-purity silicon powder are solved; and moreover, on the basis of the condition that the purity of polycrystalline silicon particles is easier to ensure, raw materials are easier to obtain, the purity of the prepared tungsten silicon target material can be ensured, and the production cost can be reduced.

Because the silicon material is easier to crush than the tungsten material, the invention takes the polysilicon grains as the raw material to be directly mixed and crushed with the tungsten powder, and the polysilicon grains can be fully mixed with the tungsten powder while being crushed, so that the tungsten-silicon mixture can be obtained through one step, and the production efficiency is improved.

Because the crushing of the polysilicon grains and the preparation of the tungsten-silicon powder are continuously carried out on one device (a ball mill), the pollution to the material caused by overlong process flow is avoided, and the purity of the material is favorably ensured; and meanwhile, the production cost is reduced.

Drawings

FIG. 1 is a microscopic structural view of a tungsten silicon target prepared in example 1 of the present invention;

FIG. 2 is a microscopic structure of the tungsten silicon target prepared in example 2 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

A preparation method of a tungsten silicon target comprises the following steps:

1) weighing tungsten powder and polysilicon grains according to the mass fraction of the polysilicon grains of 23.41-37.93 wt.% (preferably 28.43-29.96 wt.%); the Fisher average granularity of the tungsten powder is 1-10 mu m, the purity is more than or equal to 5N, the granularity of the polycrystalline silicon particles is 1-10mm, and the purity is more than or equal to 6N;

2) placing the tungsten powder and the polycrystalline silicon particles obtained in the step 1) into a ball milling tank, crushing the polycrystalline silicon particles at the rotating speed of 50-70rpm for ball milling time of 24-48h, and simultaneously uniformly mixing the two materials; preferably, the grinding balls used in the ball milling are made of the same material as tungsten powder or polysilicon particles, or are other hard alloy balls; the ball-material ratio during ball milling is 10:1-40: 1;

3) the rotating speed is increased to 200 and 300rpm, and ball milling is carried out for 30-100h to obtain tungsten silicon powder;

4) performing cold pressing and vacuum hot pressing sintering (preferably, the temperature of the vacuum hot pressing sintering is 1200 ℃ and 1400 ℃) on the tungsten silicon powder obtained in the step 3) at the vacuum degree of 10^-1-1Pa, vacuum hot pressing pressure of 20-50MPa), and machining to obtain the tungsten silicon target.

The purity of the tungsten-silicon target material prepared by the method is more than or equal to 4N5, and the relative density is more than or equal to 99%.

Step 2) and step 3), filling high-purity inert gas in the ball-milling tank for protecting tungsten powder and polysilicon particles; wherein, the high-purity inert gas is high-purity argon or high-purity helium.

It will be appreciated by those skilled in the art that the components and technical parameters of the present invention may be varied within the above ranges to achieve the same or similar technical effects as the following examples, and all fall within the scope of the present invention.