Tungsten sintered material sputtering target

A technology of sintered body and sputtering target, which is applied in the direction of sputtering coating, electric solid-state devices, semiconductor devices, etc., which can solve the problems of a lot of time cost, rising manufacturing cost, and non-disclosure of phosphorus

Active Publication Date: 2011-05-04
JX NIPPON MINING & METALS CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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.

Method used

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  • Tungsten sintered material sputtering target

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Fill the graphite mold with tungsten powder with a purity of 99.999%, a phosphorus content of less than 0.1 ppm by weight, and an average particle size of 0.6 μm, and seal it with upper and lower punches of the same material, then depressurize to a vacuum degree of 10 -2 Pa. Then, a high-frequency current of 4000A is fed up and down for 10 minutes to generate plasma between the surfaces of the internal tungsten powder, thereby purifying and activating the surface of the powder. Next, after the power supply was stopped, a pressure of 30 MPa was applied to the mold, and the mold was heated to 1800° C. by an external heating method and kept for 2 hours.

[0047] The relative density of the obtained tungsten sintered body was 99.9%, the average crystal grain size was 30 μm, and the existence of abnormal grain size was not observed. In addition, the oxygen content was 3 ppm.

[0048] As a result of sputtering using this tungsten sintered body as a target, the number of par...

Embodiment 2

[0052] Fill a graphite mold with tungsten powder with a purity of 99.999%, a phosphorus content of 0.5 wtppm, and an average particle size of 0.6 μm. After sealing with an upper punch and a lower punch of the same material, the pressure is reduced to a vacuum degree of 10 -2 Pa.

[0053] As in Example 1, a pressure of 30 MPa is applied while a high-frequency current is applied to generate plasma between the surfaces of the tungsten powder to purify and activate the powder surface, and at the same time pressurize and sinter.

[0054] During the sintering, the temperature was raised to 1550° C. by self-heating caused by the energization of the mold and the filled tungsten powder, and then kept at this temperature for 2 hours.

[0055] The relative density of the obtained tungsten sintered body was 99.8%, the average crystal grain size was 38 μm, and the existence of abnormal grain size was not observed. The oxygen content was 9 ppm. It is carried out under low sintering temper...

Embodiment 3

[0057] Fill a graphite mold with tungsten powder with a purity of 99.999%, a phosphorus content of 0.8 wtppm, and an average particle size of 0.6 μm. After sealing with upper and lower punches of the same material, the pressure is reduced to a vacuum degree of 10 -2 Pa.

[0058] As in Example 1, a pressure of 30 MPa is applied while a high-frequency current is applied to generate plasma between the surfaces of the tungsten powder to purify and activate the powder surface, and at the same time pressurize and sinter.

[0059] During the sintering, the temperature was raised to 1550° C. by self-heating caused by the energization of the mold and the filled tungsten powder, and then kept at this temperature for 2 hours.

[0060] The obtained tungsten sintered body had a relative density of 99.5%, an average crystal grain size of 45 μm, and an abnormal grain size of 70 μm. The existence range of this abnormal particle size is within a thin layer within 0.5 mm from the surface, and ...

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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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C27/04B22F3/105C23C14/14C23C14/34B22F1/00
CPCB22F3/105C22C1/045C22C27/04C23C14/165C23C14/3414B22F1/00C23C14/34C23C14/14H01L27/118H01L21/20H01L21/02631B22F3/10H01J37/3426
Inventor 铃木了小田国博
Owner JX NIPPON MINING & METALS CORP
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