A kind of high-purity tantalum powder and its preparation method

Abstract

The invention relates to a high-purity tantalum powder and a preparation method thereof. The GDMS analysis purity of the tantalum powder is greater than 99.995%. Preferably, the oxygen content of the tantalum powder is not higher than 1000ppm, the nitrogen content is not higher than 50ppm, the hydrogen content is not higher than 20ppm, the magnesium content is not higher than 5ppm, and the particle size D50<25μm.

Description

technical field [0001] The invention relates to a high-purity tantalum powder and a preparation method thereof. More specifically, the tantalum powder has a purity greater than 99.995%, an average particle size D50<25 μm, an oxygen content of no higher than 1000 ppm, a nitrogen content of no higher than 50 ppm, a hydrogen content of no higher than 20 ppm, and a magnesium content of no higher than 5 ppm. Background technique [0002] In recent years, semiconductor technology has developed rapidly, and the demand for tantalum used as a sputtered film has gradually increased. In integrated circuits, tantalum is placed between silicon and copper conductors as a diffusion barrier. The production methods of tantalum sputtering targets include ingot metallurgy (I / M) method and powder metallurgy (P / M) method. Tantalum targets with lower requirements are generally made of tantalum ingots. However, in some cases with higher requirements, the I / M method cannot be used, and the ta...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: first: because the equipment it uses is made of high-purity tantalum, it requires high equipment and is expensive

Second, because there is no deoxidation step in the method, the oxygen content of the resulting product is extremely unstable, with great differences, and it is difficult to be less than 1000ppm

Third, due to the grading treatment, the availability of materials is greatly reduced, and it is difficult to refine the particle size of tantalum powder

[0010] At present, the production process of metallurgical grade tantalum powder generally adopts the method of simultaneous dehydrogenation and deoxidation, which will cause limitations in the design process parameters

Specifically, if the temperature is set too low, it will cause incomplete dehydrogenation and lead to high hydrogen content in the final product

At the same time, the properties (such as lattice constant, resistance, hardness, etc.) of tantalum after hydrogen absorption cannot be completely eliminated.

If the temperature is set too high, the hydrogen can be fully released, but it will cause the sintering of the tantalum particles to grow, and at the same time cause the magnesium or magnesium oxide particles to be wrapped inside the tantalum particles, which are difficult to remove in the subsequent pickling process, resulting in The controllability of the particle size is poor, and it is difficult to meet the requirements of the average particle size D50<25μm while the oxygen content is lower than 1000ppm

Unfortunately, it can also lead to high levels of magnesium

In addition, in the current process, after dehydrogenation and deoxidation, the tantalum powder is pickled, dried, and sieved to become the final product without subsequent heat treatment, which will lead to residual magnesium metal after deoxidation and H , F and other impurities can not be removed, so that the content of magnesium and hydrogen in the final product is too high

[0011] Obviously, the existing technology is difficult to meet the needs of sputtered films in semiconductor technology

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