JP2000319774A - Sputtering target material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce particles and sheet resistance value at the time of sputtering and to increase the productivity and yield by controlling the average grain size of the recrystallized crystals in a recrystallized sheet obtd. by subjecting a W/Mo alloy rolled sheet or a W rolling stock to heat treatment to the value equal to or below a specified one. SOLUTION: A W ingot sintered in hydrogen is rolled at about 1300 to 1600 deg.C in such a manner that it is not recrystallized to form into a W sheet. In this way, the W sheet having about 99.9% relative density can be obtd. This sheet is moreover subjected to heat treatment for about 30 min in a furnace heated at about 1700 to 1800 deg.C and is recrystallized. The obtd. recrystallized grains have uniform grain size, and the average grain size thereof is <=100 μm. Furthermore, in the containing gas used, the content of oxygen is controlled to 10 ppm, nitrogen to <10 ppm, and the total is controlled to <=100 ppm. By a target for sputtering using this W sheet, the sheet resistance value of the formed W film remarkably reduces. The generating frequency of foreign matters (particles) generated at the time of film formation exceedingly reduces as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering target material, and more particularly, to a sputtering target material made of tungsten (W) or a tungsten-molybdenum (W / Mo) alloy.

[0002]

2. Description of the Related Art In recent years, the production of flat displays represented by liquid crystal displays has been rapidly expanding. Along with this, for example, the demand for a transparent conductive film used for a display and a metal wiring film for a gate, a source, and a drain of an electric field transistor are also rapidly increasing.
It is also required to increase the speed in terms of its characteristics.

As a sputtering target material used for such a flat panel display, IT
O, Al, Cr, Ta, W / Mo alloy and the like can be mentioned.

In a semiconductor, a gate, a source,
And W is used for a metal wiring film used for a drain, etc. Among them, there is a problem that a W / Mo alloy and a W target are sputtered and their particles are formed, and the film thickness varies. There was a problem that the resistance value was high.

[0005]

The current target W
/ M alloy and W plate generally use a rolled material. The texture of the rolled material is fibrous, and when viewed from the sputter surface, the sphere is formed into a thin layer with a state in which spheres are crushed and extended in one direction and gathered. For this reason, organizationally, large and small things have come together.

[0006] Rolled materials such as W / Mo-containing and W-plates tend to have the same crystal orientation as sintered products, and the direction in which the W / Mo alloy particles and W particles fly depends on the crystal orientation. The thickness distribution varies. As a result, the sheet resistance varies. For this reason, productivity is reduced because the thinnest portion meets a certain thickness.

Further, in order to obtain a plate-like W / Mo alloy having uniform particles and W, a W / Mo alloy compact or a W compact is sintered in a hydrogen furnace or subjected to canning HIP. Although there is a method of producing the particles, the density of the target (porosity) is also involved in the generation of particles, and the higher the density, the better (there is less porosity).

However, in the above method, the relative density can be increased only up to 99.0% at best, and the material produced by the canning HIP has a large gas content, so that the sheet resistance after sputtering is high. In other words, the number of particles generated during sputtering increases, and the size is limited as compared with a rolled material.

Therefore, a technical problem of the present invention is to obtain a W / Mo target and a W target having a uniform particle size, thereby reducing the particles and sheet resistance during sputtering, and reducing the product productivity and yield. An object of the present invention is to provide a sputtering target material that can be significantly improved.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors controlled the conditions at the time of rolling and the temperature conditions for recrystallization so that the gas content was 100 ppm or less and the relative density was less. 99.5% or more, and crystal grains are 100
It has been found that a W / Mo alloy plate and a W plate having uniform particles of μm or less can be produced, and the present invention has been accomplished.

That is, according to the present invention, there is provided a recrystallized sheet obtained by heat-treating a rolled W / Mo alloy sheet or a rolled W material, wherein the average recrystallized grain size is 100 μm or less. Is obtained.

Further, according to the present invention, there is provided a sputtering target material characterized in that the sputtering target material has a relative density of 99.5% or more.

Further, according to the present invention, there is provided a sputtering target material characterized in that the content of any one of the above sputtering target materials is 100 ppm or less.

Specifically, in the present invention, it is preferable that the particles of the sputtering target be uniform and fine, so that a W / Mo alloy plate or a W plate (relative density ≧
99.5%) was heated at 1300 ° C. or more to recrystallize
A W / Mo alloy plate or a W plate having a uniform grain size of 00 μm or less is used as a target for sputtering. The crystal orientation of the recrystallized material of the present invention is random.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) W sintered in hydrogen
Using an ingot, a W plate was rolled at a heating temperature of 1300 to 1600 ° C. so as not to recrystallize during processing. At this time, the working ratio of the plate (rate of reduction in plate thickness) was 82%, and the relative density was 99.9%. This plate is bisected, and one is 1700 ° C
Heat treatment in a furnace at 炉 1800 ° C. for 30 minutes for recrystallization.

The rolled product has a fiber structure, and the recrystallized product has a uniform particle size and an average particle size of about 90 μm.
m. In addition, both gas contents are 10 pp oxygen.
m, nitrogen <10 ppm, carbon 10 ppm, total 1
It was less than 00 ppm.

Using the above two types of W plates, secondary processing such as cutting and polishing was performed and used as a sputtering target, and the sheet resistance after forming a W film by sputtering was measured.

As a result, when the sheet resistance value of the fiber structure was 100 by rolling alone, the sheet resistance value of the recrystallized structure was as low as 88.

FIG. 1 is a diagram showing the sputtering characteristics of the sputtering target material according to the embodiment of the present invention. In addition, the sputtering characteristics of the conventional sputtering target are also shown.

Curve 11 (inventive material) and Curve 1 in FIG.
2 (conventional material), when the recrystallized W material of the present invention is used for a sputtering target, the number of foreign particles (particles) Np generated in the film formation is reduced as compared with the case where the conventional W material is used. Despite the increase in the number NH, the number was remarkably reduced, and it was found that the frequency of generation of particles was lower than that of the conventional product.

(Second Embodiment) W sintered in hydrogen
Using a / Mo (W50 wt%: Mo 50 wt%) ingot, a W / Mo plate was obtained by rolling at a heating temperature of 1400 to 1600 ° C. so as not to recrystallize during processing. At this time, the working ratio of the plate (the reduction ratio of the plate thickness) is 85%, and the relative density is 99.
9%.

The plate is bisected, and one is
It was recrystallized by heat treatment in a furnace at 00 ° C. for 30 minutes.

As in the case of the first embodiment, the rolled product had a fiber structure, and the recrystallized product had a uniform particle size and an average particle size of about 70 μm.

The content of the gas was 20 ppm for oxygen, 10 ppm for nitrogen and 10 ppm for carbon.
m or less.

In the same manner as in the first embodiment, secondary processing such as cutting and polishing was performed to obtain a sputtering target, and the sheet resistance after forming a W / Mo film by sputtering was measured. As a result, when the sheet resistance value of the fiber structure was set to 100 by rolling alone, the sheet resistance value of the recrystallized structure was as low as 90.

(Third Embodiment) W sintered in hydrogen
Using a / Mo (W17.5 wt%, Mo 82.5 wt%) ingot, a W / Mo plate was obtained by rolling at a heating temperature of 1300 to 1500 ° C. so as not to recrystallize during processing. At this time, the working ratio of the plate (rate of thickness reduction) was 80%, and the relative density was 99.9%. Divide this plate into two, one with 130
Heat treatment was performed in a furnace at 0 ° C. to 1500 ° C. for 30 minutes for recrystallization.

As in the case of the first embodiment, only the rolled product had a fiber structure, and the recrystallized product had a uniform particle size and an average particle size of about 60 μm. Both gas contents are 10 ppm of oxygen, 10 ppm of nitrogen, 10 p of carbon.
pm, and the total was 100 ppm or less.

In the same manner as in the first embodiment, secondary processing such as cutting and polishing was performed, and the sheet resistance after forming a W / Mo film by sputtering was measured using a sputtering target. As a result, assuming that the sheet resistance of the fiber structure was 100 by rolling alone, the sheet resistance of the recrystallized structure was as low as 87.

[0030]

As described above, according to the present invention,
By selecting the rolling conditions and the recrystallization temperature of the W / Mo plate and the W plate, a W / Mo target and a W target having a uniform particle size can be obtained, thereby reducing the particles and sheet resistance during sputtering and reducing the product. A sputtering target material that can significantly improve productivity and yield can be provided.

Further, according to the present invention, it is possible to provide a sputtering target material capable of suppressing the reduction of sheet resistance and the generation of particles during sputtering by controlling the crystal grain size.

Further, according to the present invention, it is possible to provide a sputtering target material capable of remarkably improving the product yield and the productivity and reducing the product cost.

Further, according to the present invention, it is possible to provide a sputtering target material which can be easily industrialized because a normal W plate manufacturing process can be used and a product can be easily produced by controlling rolling conditions and recrystallization conditions. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing sputtering characteristics of a sputtering target material according to an embodiment of the present invention.

Claims (3)

[Claims] 1. A sputtering target material, which is a recrystallized plate obtained by heat-treating a rolled W / Mo alloy plate or a rolled W material, wherein the average recrystallized grain size is 100 μm or less. 2. The sputtering target material according to claim 1, which has a relative density of 99.5% or more. 3. The sputtering target material according to claim 1, wherein the gas content is 100 ppm or less.