Tungsten sintered material sputtering target

Abstract

Provided is a tungsten sintered material sputtering target having a phosphorus content of 1 ppm by weight or less, with the remainder being tungsten and unavoidable impurities. A decrease in the strength of the target and abnormal tungsten particle growth are strongly influenced by the phosphorus content, and particularly when the phosphorus content exceeds 1 ppm, crystal particles that have undergone abnormal growth will be present in the tungsten target. Consequently, the issue is to prevent abnormal tungsten particle growth and increase target product yield by vigorously identifying phosphorus contained in the tungsten as a harmful impurity and keeping the content to a minimum.

Description

technical field [0001] The present invention relates to a tungsten sintered body target used when forming gate electrodes of ICs, LSIs, etc., wiring materials, etc. by sputtering. Background technique [0002] In recent years, with the high integration of ultra-LSI, research has begun to use materials with lower resistance values ​​as electrode materials or wiring materials. Among such materials, high-purity tungsten with low resistance values ​​and thermal and chemical stability is used as electrode materials or wiring material. [0003] The electrode materials or wiring materials for this super LSI are generally produced by sputtering and CVD. Among them, the structure and operation of the device in the sputtering are relatively simple, can be easily formed into a film, and are low in cost. more widely used. [0004] However, a tungsten target used for forming an electrode material or a wiring material for a super LSI by sputtering requires a relatively large size of 300...

AI Technical Summary

Problems solved by technology

[0006] However, the method of rolling the ingot melted by the electron beam or rolling the sintered body obtained by pressure sintering of tungsten powder is mechanically brittle because the crystal grains tend to be coarsened, and has the disadvantage of being obtained by sputtering. The film is prone to the problem of granular defects called particles

In addition, although the CVD-W method exhibits good sputtering characteristics, there is a problem that it takes a lot of time and cost to make the target.

However, at this time, only the total amount of impurities and impurities (Fe, Cr, Ni, Na, K, U, Th, etc.) that are not preferable in semiconductors are specified, and the issue of phosphorus is not disclosed at all.

[0011] Based on the above, there are problems with tungsten targets, that is, the occurrence of target defective products, the decrease in the yield of the target manufacturing process, and the increase in manufacturing costs.

Images