Tungsten sintered sputtering target and manufacturing method thereof

Abstract

Provided is a tungsten sintered compact sputtering target containing iron as an impurity in an amount of 0.8 wtppm or less, and remainder being tungsten and other unavoidable impurities, wherein a range of iron concentration in a target structure is within a range of ±0.1 wtppm of an average concentration. Additionally provided is a tungsten sintered compact sputtering target according to claim 1 or claim 2, wherein a relative density of the target is 99% or higher, an average crystal grain size is 50 µm or less, and a crystal grain size range is 5 to 200 µm. The present invention aims to inhibit abnormal grain growth in the tungsten target by reducing the amount of iron in the tungsten sintered compact sputtering target.

Description

technical field [0001] The present invention relates to a tungsten sintered compact target used when forming gate electrodes of ICs, LSIs, etc., wiring materials, and the like by sputtering, and a method for manufacturing the target. Background technique [0002] In recent years, with the high integration of super-LSI, the use of materials with lower resistance values ​​as electrode materials or wiring materials is being studied. Among such materials, high-purity tungsten, which has low resistance values ​​and is thermally and chemically stable, is used as electrode materials. or wiring material. [0003] This super LSI electrode material or wiring material is generally produced by sputtering and CVD. For sputtering, the structure and operation of the device are relatively simple, film formation can be easily made, and the cost is low, so it is more expensive than CVD. widely used. [0004] Tungsten targets are required to have high purity and high density. However, in rec...

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Problems solved by technology

[0011] On the other hand, it is known that there are problems in that abnormal grain growth occurs and the target strength decreases at the stage of manufacturing tungsten sintered compact sputtering target, thereby reducing the product yield.

[0013] However, although the reduction of phosphorus in tungsten is very effective, in the strict sense, abnormal grain growth still occurs, and further improvement is required.

[0014] Generally, sintered compacts are produced by HIP to increase the density and strength of tungsten targets, but there is a problem that abnormal grain growth at this stage will cause processing defects in subsequent processes, so it is necessary to further reduce this problem. abnormal grain growth

[0015] As a patent document other than the above, there is Patent Document 9 in which the particle size and crystal structure are adjusted by rotary forging, but the current situation is that the prevention of abnormal grain growth of tungsten is not a subject, and there is no specific means for it.

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