JP2000001773A - Dielectric sputtering target material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stable dielectric sputtering target material and its producing method by which production of cracks and chipping of the target surface are reduced during sputtering a (Ba, Sr)Ti oxide sintered body sputtering target. SOLUTION: This dielectric sputtering target material is expressed by BaxSryTiO3-z (0<x<1, 0<y<1, 0.98<(x+y)<=1.00, 0<z<=0.03) and has >=95% density of the sintered body, 0.5 to 10 μm average grain size of the sintered body and >=3 ppm and <=100 ppm C1 content. The target material is produced by subjecting a source material powder of BaxSryTiO3 (0<x<1, 0<y<1, 0.98<(x+y)<=1.00) having <=1 μm average grain size and >=5 ppm and <=150 ppm C1 content to hot-pressing at 1150 to 1300 deg.C sintering temp. under 10 to 50 MPa sintering pressure in vacuum or in an inert gas atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric sputtering target for forming a capacitor film and a functional dielectric thin film of a next-generation highly integrated semiconductor memory and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a sputtering target for forming a dielectric thin film has been strontium barium titanate [(B
a, Sr) TiO3] target powder is formed by sintering under normal pressure in a vacuum sintering or reducing atmosphere, or by hot pressing after molding a Ti-based oxide powder of (a, Sr) TiO3]. Has been obtained. For example, Japanese Patent Laid-Open No. 62-
58510 and JP-A-6-330297, the oxide constituting the target is an oxygen-deficient oxide in which oxygen in the constituent elements is reduced.

[0003]

The above-mentioned (Ba, Sr)
In a sputtering sputtering target of a Ti-based oxide sintered body, the target surface is exposed to plasma and heated during sputtering. On the other hand, since the opposite backing plate side is water-cooled, thermal stress is generated on the target surface, and when sputtering is applied, cracks occur in the target and chipping occurs in a small area of the surface. there were. Therefore, as a result of intensive studies, the present invention provides a stable dielectric sputtering target material without such a problem and a method for manufacturing the same.

[0004]

From the above viewpoints, the present inventor has studied manufacturing conditions in which abnormal grain growth does not occur in order to finely control the average crystal grain size of the target.
It was found that the Cl content in the raw material powder was related to the abnormal grain growth phenomenon at the time of sintering, and it was found that a moderate amount of Cl promoted sintering to exert a practically sufficient effect. is there.

[0005] The present invention has been made based on the above findings, that is, the sintered body density is 95% or more, the sintered body average particle size is 0.5 to 10 (μm) ,
BaxSryTiO3-z (0 <x <1, 0 <y <) in which the Cl content is 3 (ppm) or more and 100 (ppm) or less.
1, 0.98 <(x + y) ≦ 1.00, 0 <z ≦ 0.0
3) Dielectric sputtering target material.

[0006] Further, the content of Cl is 5 (ppm) or more and 15 (ppm) or more.
0 (ppm) or less and BaxSryTiO 3 (0 <x <1, 0 <y <1,
0.98 <(x + y) ≦ 1.00) Using raw material powder, sintering temperature 1150-1300 ° C., sintering pressure 10-50MP
a, A method for producing a dielectric sputtering target material which is hot-pressed in a vacuum or an inert gas atmosphere.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. First, in order to prevent abnormal grain growth during sintering and to increase the sintering density at a relatively low temperature, it is necessary to control the amount of Cl in the raw material powder to 5 (ppm) or more and 150 (ppm) or less. As the Cl analysis value at this time, a value obtained by extracting a Cl component from the raw material powder by a steam decomposition method and then quantifying it by ion chromatography was used.

That is, BaxSryTiO3 (0 <x <1, 0.98 <) having an average particle diameter of 1 (μm) or less controlled at a Cl content of 5 (ppm) or more and 150 (ppm) or less.
(X + y) ≦ 1.00) Using raw material powder, sintering temperature 115
By hot pressing at 0 to 1300 ° C., at a sintering pressure of 10 to 50 MPa, in an atmosphere vacuum or in an inert gas atmosphere, the relative density of the sintered body is 95% or more, and the average particle diameter of the sintered body is 0.5 to 10 (Μm) and the Cl content is 3 (pp
m) BaxSryTi not less than 100 (ppm)
O3-z (0 <x <1, 0 <y <1, 0.98 <(x +
y) ≦ 1.00, 0 <z ≦ 0.03) The sintered body target can be stably manufactured.

The reason why the average particle diameter of the sintered body is set to 0.5 to 10 (μm) is that if the particle size of the sintered body is large, the transverse rupture strength is 20 kgf /
As a result, an average bending strength of ² mm or more cannot be obtained.As a result, the target cannot fully withstand the thermal stress during sputtering and the surface breakage increases. Therefore, the average particle size of the sintered body needs to be 0.5 to 10 (μm), and preferably 0.5 to 3 (μm).

The reason that the Cl content in the raw material powder is controlled to be 5 (ppm) or more and 150 (ppm) or less is that when the Cl content is 5 (ppm) or less, the relative density of the sintered body becomes 95%.
%, The sintering temperature must be increased to 1300 ° C. or higher. As a result, the internal stress of the sintered body increases, and the cracking resistance during sputtering decreases.
On the other hand, when the Cl content exceeds 150 (ppm), abnormally grown grains having a crystal grain size exceeding 20 (μm) or more due to heterogeneous nucleation grow from a sintering temperature of about 1200 ° C., and the bending strength is extremely high. And cracking resistance during sputtering is reduced. Preferably, the Cl content is at least 20 (ppm) 10
It is better to be 0 (ppm) or less. A sintered body made from raw material powder satisfying this condition has a density of 95% or more and an average particle size of 1
３3 (μm) sintered body has an average bending strength of 25 kgf / mm
^Two or more are obtained.

The hot pressing is performed at a sintering temperature of 1150 to 1300 ° C., a sintering pressure of 10 to 50 MPa, in an atmosphere of vacuum or in an inert gas atmosphere. The average particle size is 0.5 to 10 (μ
This is the basic sintering condition under which the sintered body of m) can be obtained and the internal stress can be relatively reduced.

From the above, BaxSryTiO3 (0 <x <1, 0 <y <) having an average particle size of 1 (μm) or less is considered.
1, 0.98 <(x + y) ≦ 1.00) The reason for using the raw material powder is to obtain a sintered body relative density of 95% or more.
The raw material powder must have at least an average particle size of 1 (μm) or less, and a sintering temperature of 1300 ° C. or less and a sintering density of 95 μm.
% Is obtained, and sintering in a reducing atmosphere results in a slight amount of oxygen deficiency Z, and the range is 0 <Z ≦ 0.03.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples. Examples 1 to 12 of the present invention, which are shown in Examples and Comparative Examples in Table 1, have BaxSry having an average particle diameter and a Cl content.
TiO3 (0 <x <1, 0 <y <1, 0.98 <(x +
y) ≦ 1.00) The raw material powder was filled in a carbon mold having an inner diameter of φ5 ″, and hot-pressed at predetermined temperatures, heating rates, pressures, and atmospheric conditions shown in Table 1. The same conditions were applied to the comparative targets 1 to 8 having Cl amounts out of the range, and the target of the present invention and the target for evaluation of the comparative target were formed on a φ4 ″ Si wafer for 10 minutes under sputtering conditions shown in Table 2. The film formation rate was measured, and the RF sputtering power was increased stepwise by 50 (W), and the same measurement was repeated. The power at the time when cracks occurred in the target was used as a crack resistance evaluation value. Further, the film formation rate measured immediately before the target cracking was taken as the maximum film formation rate.

The results are shown in Table 1. Table 2 shows the sputtering test conditions of the target of the present invention and the comparative target. In the evaluation of this target, when the average bending strength was compared, the target of the present invention was 20 to 29.
(Kgf / mm ² ), whereas the comparative target was 4 to 12 (kgf / mm ² ), 1/5 to 1/2 or less. The comparison target is inferior to 39 to 92 (/ min), compared to 240 to 316 (/ min). From these facts, it is clear that the present invention has better performance than the comparison.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

As described above, BaxSryTiO
3-z (0 <x <1, 0 <y <1, 0.98 <(x +
y) ≦ 1.00, 0 <z ≦ 0.03) The sintered body target has a relative density of 95% or more, a sintered body average particle size of 0.5 to 10 (μm), and contains Cl If the quantity is 3 (pp
m) or more and 100 (ppm) or less. A sintered target that satisfies this condition has high flexural strength, suppresses internal stress low, suppresses the occurrence of cracks in the target due to thermal stress during sputtering, and shows stable sputtering behavior. By using the present sputtering target, an improvement in product yield can be expected, and the present invention exhibits more performance than before, so that it can be suitably used.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akifumi Mishima 1-297 Kitabukurocho, Omiya City, Saitama F-term in Mitsubishi Materials Research Laboratory (reference) 4K029 BA50 BC00 BD01 DC05 DC09 4M104 BB36 DD40 GG16

Claims (2)

[Claims] 1. A dielectric sputtering target having a sintered body density of 95% or more, a sintered body average particle size of 0.5 to 10 (μm), and a Cl content of 3 (pp
m) or more and 100 (ppm) or less, and BaxSryT
iO3-z (0 <x <1, 0 <y <1, 0.98 <(x
+ Y) ≦ 1.00, 0 <z ≦ 0.03). 2. The dielectric sputtering target, wherein the Cl content is 5 (ppm) or more and 150 (ppm) or less and BaxSry whose average particle diameter is 1 (μm) or less.
TiO3 (0 <x <1, 0 <y <1, 0.98 <(x +
y) ≦ 1.00) Using raw material powder, sintering temperature 1150-1
A method for producing a dielectric sputtering target material, wherein hot pressing is performed at 300 ° C., a sintering pressure of 10 to 50 MPa, and an atmosphere of a vacuum or an inert gas atmosphere.