JP2000234167A - Molybdenum sputtering target material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Mo sputtering target material of high quality in which the problems that particles are largely generated and arcing occurs according to conditions at the time of sputtering are solved and to provide a method for producing it. SOLUTION: This Mo sputtering target material is composed of a recrystallized Mo sheet with random crystal orientation obtd. by subjecting an Mo rolling stock to heat treatment, and in which the average of the recrystallized grain size is <=100 μm. For producing the Mo sputtering target material, an Mo stock is subjected to rolling at >=70% rolling radio to obtain an Mo sheet having 99.5% relative density, which is subjected to heat treatment at 1,100 to 1,200 deg.C and is recrystallized to obtain a sputtering target material composed of a Mo sheet having a structure of uniform grains of <=100 μm.

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 substantially composed of molybdenum (Mo) used for forming a transparent conductive film of a flat display represented by a liquid crystal display and an electrode of a semiconductor device.

[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 transparent conductive films used in displays and metal wiring films used for gates, sources, and drains of electric field transistors has been rapidly increasing, and higher speeds due to their characteristics have also been required. Have been.

As a sputtering target material used for such a flat panel display, IT
O (In ₂ O ₃ : SnO ₂ ), Al, Cr, Ta, W,
Mo and the like.

[0004] Among these sputtering target materials, the demand for Mo is increasing.

At present, generally, a rolled material is used as a target Mo plate. The structure of the Mo rolled material is in a fibrous form, and when viewed from the sputter surface, the spheres are crushed in one direction and extended to form a thin layer. For this reason, Mo-rolled materials are organized such that large and small Mo are organized.

[0006]

When the above-mentioned conventional Mo target material is sputtered under a sputtering condition for forming a film at a high speed, particles are generated, foreign matter adheres on the film, or somewhere in the apparatus. The deposits adhere to the target, causing arcing and damaging the substrate, rendering it inoperable. As a result, the yield decreases and the production cost increases.

[0007] Rolled materials tend to have a uniform crystal orientation as compared to sintered products. Since the direction in which the Mo particles fly depends on the crystal orientation, the film thickness distribution varies, and as a result, the sheet resistance may vary.

On the other hand, in order to obtain plate-like Mo having uniform particles, there are methods of sintering the Mo compact in a hydrogen furnace or making it by a canning HIP. Is related to the density (porosity) of the target, and the higher the density, the better (there is less pores).

However, in the above-mentioned method, the relative density can be increased only up to 99.0% at best, and the gas produced by the canning HIP has a large gas content.
The sheet resistance after the sputter increases. In addition, there is a limit on the size compared to the rolled material.

Therefore, a technical problem of the present invention is to provide a high-quality Mo which has solved the problem that a large amount of particles are generated or arcing occurs depending on the conditions at the time of sputtering.
An object of the present invention is to provide a sputtering target material and a method for manufacturing the same.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventor has controlled the conditions at the time of rolling the Mo material and the temperature conditions for recrystallization to achieve a gas content of 100 ppm.
Below, when the relative density is 99.5% or more,
An Mo plate having a uniform particle size of 0 μm or less can be produced, and the present invention has been accomplished.

According to the present invention, a recrystallized M having a random crystal orientation obtained by heat-treating a Mo-rolled material.
An Mo sputtering target material is obtained which is an o-plate and has an average recrystallized grain size of 100 μm or less.

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

According to the present invention, the Mo sputtering target material has a gas content of 100 p
pm or less is obtained.

Further, according to the present invention, the Mo material is subjected to rolling at a rolling reduction ratio of 70% or more, so that the relative density is 9%.
Mo sputtering obtained by obtaining a 9.5% Mo plate, heat-treating at 1100 ° C. to 1200 ° C., and recrystallizing to obtain a sputtering target material made of a Mo plate having a uniform grain structure of 100 μm or less. A method for manufacturing the target material is obtained.

In short, in the present invention, since it is better that the particles of the sputtering target be uniform and fine, a Mo plate (relative density ≧ 99.5) made at a rolling reduction ratio of 70% or more is preferred.
%) Is heat-treated at 1100 ° C. to 1200 ° C. and recrystallized to use a Mo plate having a uniform structure of 100 μm or less as a Mo plate for sputtering, and the crystal orientation of the recrystallized material is random.

[0017]

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

First, using a Mo ingot sintered in hydrogen, a Mo plate was rolled at a heating temperature of 1300 ° C. or less so as not to recrystallize during processing. At this time, the working ratio of the plate (the reduction ratio of the plate thickness) was 82%, and the relative density was 99.9%. This plate is bisected, and one is from 1100 ° C. to 1200
It was recrystallized by heat treatment in a furnace at 30 ° C. for 30 minutes. A-plane, B-plane and C-plane of the recrystallized Mo plate (material of the present invention) at this time
1 to 3 show enlarged micrographs showing the metal structure of the surface. For comparison, A was not recrystallized.
FIGS. 4 to 6 show enlarged micrographs showing the metal structures on the side, the B side, and the C side.

As shown in FIGS. 4 to 6, only the rolled product has a fiber structure. On the other hand, the recrystallized product according to the embodiment of the present invention had a uniform particle size and an average particle size of about 70 μm. Both contained 30 ppm of oxygen, <10 ppm of nitrogen, and 20 ppm of carbon, and the total gas content was 100 ppm or less.

Using the above two types of Mo plates, secondary processing such as cutting and polishing is performed to form a sputtering target.
When the sputter ring characteristics were compared and examined, the results were as shown in FIG.

From FIG. 7, when the recrystallized Mo material (material of the present invention) according to the embodiment of the present invention shown in the curve 1 is used for the sputtering target, the conventional Mo material shown in the curve 2 can be obtained.
Compared to the case of using the material (conventional material), the number of foreign particles (particles) Np generated in the film formation is remarkably reduced irrespective of the increase in the number of processed NH, and the frequency of generation of particles is lower than that of the conventional product. did.

Further, using 10 targets each made of the material of the present invention and the conventional material produced by the same method as described above, the spattering characteristics were compared and the degree of occurrence of arcing was examined. As a result, the material of the present invention has a degree of arcing,
0 out of 10 sheets. On the other hand, the conventional material is 10
Three out of three sheets. This shows that the material of the present invention has better quality.

In the evaluation of the number of occurrences of the arcing, only ten sheets were evaluated because the processed material was expensive. However, sufficient results were not obtained to achieve the object of the present invention. Obtained.

[0024]

As described above, according to the present invention,
By selecting the rolling conditions and recrystallization temperature of the Mo plate using ordinary Mo plate manufacturing processes and equipment, a Mo target having a uniform particle size can be obtained, thereby reducing the generation of particles and arcing during sputtering. In addition, it is possible to provide a Mo sputtering target material capable of significantly improving the product yield of a flat display and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a photomicrograph showing a metal structure on an A-side of a Mo sputtering target material according to an embodiment of the present invention.

FIG. 2 is a micrograph showing a metal structure on a B surface of the Mo sputtering target material shown in FIG. 1;

FIG. 3 is a photomicrograph showing a metal structure on a C-plane of the Mo sputtering target material shown in FIGS. 1 and 2;

FIG. 4 is a photomicrograph showing a metal structure on a surface A of a conventional Mo sputtering target material.

FIG. 5 is a micrograph showing a metallographic structure on a B surface of the Mo sputtering target material shown in FIG. 4;

FIG. 6 is a micrograph showing a metal structure on a C-plane of the Mo sputtering target material shown in FIGS. 4 and 5;

FIG. 7 is a diagram showing the sputtering characteristics of a sputtering target material according to an embodiment of the present invention, and also shows the characteristics of a conventional example.

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[Procedure amendment]

[Submission date] April 5, 2000 (200.4.5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

According to the present invention, by sintering in hydrogen
Rolling the obtained Mo ingot at a temperature of 1300 ° C or less
A recrystallized Mo plate having a random crystal orientation obtained by heat-treating the Mo-rolled material produced by the above method, wherein the average recrystallized grain size is 100 μm or less. Wood is obtained. Therefore, a technical problem of the present invention is to provide a high-quality Mo sputtering target material which solves the problem that a large amount of particles are generated or arcing occurs depending on conditions at the time of sputtering, and a method of manufacturing the same. is there.

Claims (4)

[Claims] 1. A recrystallized Mo plate having a random crystal orientation obtained by heat-treating a Mo-rolled material,
A Mo sputtering target material having an average recrystallized grain size of 100 μm or less. 2. The Mo sputtering target material according to claim 1, wherein the Mo sputtering target material has a relative density of 99.5% or more. 3. The Mo sputtering target material according to claim 2, wherein the content of gas is 100 ppm or less. 4. A Mo plate having a relative density of 99.5% is obtained by subjecting a Mo material to rolling at a rolling ratio of 70% or more.
Heat-treated at 100 ° C to 1200 ° C and recrystallized to 100
A method for producing a Mo sputtering target material, comprising obtaining a sputtering target material made of a Mo plate having a uniform grain structure of μm or less.