JP3129046B2 - Sputtered sintered target material with excellent thermal shock resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered target material exhibiting excellent thermal shock resistance when used for forming a dielectric thin film for an electronic device such as a display device by sputtering. .

[0002]

2. Description of the Related Art Conventionally, when the above-mentioned dielectric thin film is formed by sputtering, a composite oxide of Ba and Ti [hereinafter referred to as BaTiO ₃ ] or a composite oxide of Ba, Sr and Ti [hereinafter, (Ba, It is known to use a sintered target material composed of [Sr) TiO ₃ ]. Further, the above-mentioned sintered target material is composed of BaCO ₃ powder, SrCO ₃ powder, and TiO ₂
Using a powder, a mixed powder of BaCO ₃ powder and TiO ₂ powder, or a mixed powder of SrCO ₃ powder and TiO ₂ powder is subjected to heat treatment in air at a temperature of 1100 to 1200 ° C. for a predetermined period of time. BaTiO ₃ powder and SrTiO ₃ powder were synthesized, and these Ba
The mixed powder of the TiO ₃ powder and the SrTiO ₃ powder is subjected to a heat treatment under the same conditions as above to synthesize a (Ba, Sr) TiO ₃ powder, and then the (Ba, Sr) T obtained as a result.
From iO ₃ powder or the above-mentioned BaTiO ₃ powder, a green compact is formed and usually sintered in air at a temperature of 1250 to 1350 ° C., or in air, a temperature of 1250 to 13
Hot pressing is performed under the conditions of 50 ° C. and a pressure of 200 kgf / cm ² , or the sintered body obtained by the ordinary sintering is treated with H.
It is also well known that it is manufactured by performing or performing IP (hot isostatic pressing).

[0003]

On the other hand, in recent years, high power and labor saving of the sputtering apparatus have been remarkable, and the size of the target has tended to increase accordingly. When the size is increased, the thermal shock resistance is not sufficient, so that cracks are liable to occur during the sputtering, in combination with the increase in the severity of the sputtering conditions, and the service life is relatively short.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoint, the above-mentioned conventional sintered target material was focused on, and as a result of conducting research, the BaTiO ₃ powder and (Ba, S
r) TiO ₃ powder in vacuum or reducing atmosphere,
Performing oxygen reduction heat treatment at a temperature of 1200 to 1450 ° C. for a predetermined time, or (Ba, Sr)
By performing the synthesis of the TiO ₃ powder under the same conditions as the oxygen reduction heat treatment, to reduce the oxygen content in these powders,
In order to suppress the progress of oxidation by using the powder having a reduced oxygen content, ordinary sintering or hot pressing is performed under the above-described ordinary conditions in vacuum, and HIP processing is performed in addition to the ordinary sintering. BaTiO ₃ or (Ba, S
r) than the stoichiometric oxygen content of TiO ₃ 4.9 to 10%
BaTiO _3-x or (Ba, Sr) with low oxygen content
When a sintered target material composed of TiO _3-x (X is 0.147-0.3 corresponding to 4.9-10% of the theoretical oxygen content) is produced, the resulting sintered target material is: It has better thermal shock resistance, so it is larger, and even when subjected to spatter under more severe conditions, the generation of cracks is remarkably suppressed, and excellent performance is exhibited over a long period of time. The research results were obtained.

The present invention has been made on the basis of the above-mentioned research results and is based on BaTiO ₃ or (Ba, S
r) than the stoichiometric oxygen content of TiO ₃ 4.9 to 10%
BaTiO _3-x or (Ba, Sr) with low oxygen content
It is characterized by a sputtering sintered target material composed of TiO _3-x (X: 0.147 to 0.3). In the sintered target material of the present invention, the oxygen content is set to be 4.9 to 10% lower than the theoretical oxygen content because if the ratio is less than 4.9%, a desired excellent heat resistance is obtained. This is because the impact property cannot be ensured, and when the proportion exceeds 10%, the oxygen content in the sputtered thin film varies, and the characteristics of the thin film are impaired.

[0006]

EXAMPLES Next, the sintered target material of the present invention will be specifically described with reference to examples. First, the average particle size: 1.5μ
m BaCO ₃ powder, 1.3 μm SrCO ₃ powder,
And 1.2 μm of TiO ₂ powder, and the BaC
The O ₃ powder and the TiO ₂ powder, and the SrCO ₃ powder and the TiO ₂ powder were each mixed by a wet ball mill for 8 hours, dried, and then subjected to a heat treatment in air at a temperature of 1150 ° C. for 2 hours. Pulverized to average particle size: 1.2
μm BaTiO ₃ powder and 0.9 μm SrTiO ₃
A powder was synthesized.

Then, the above BaTiO ₃ powder and SrTi
O ₃ powder and a predetermined ratio are blended,
2 × 10 ^-5 torr
(Ba, Sr) Ti in which the heat treatment was performed at a predetermined temperature within a range of 1200 to 1450 ° C. for 5 hours in a vacuum of 5 ° C. to reduce the oxygen at a predetermined ratio compared to the theoretical oxygen content.
O _3-x was synthesized, ground in a wet ball mill for 24 hours, dried, and subsequently the resulting (Ba, Sr) T
iO _3-x powder and the BaTiO ₃ powder of the (Ba, Sr) is subjected to heat treatment under the same conditions as the synthesis conditions of TiO _3-x powder, also in comparison with the theoretical oxygen content at a predetermined ratio In the BaTiO _3-x powder which is reduced in oxygen, the conditions for minimizing the fluctuation of the contained oxygen, that is, 2 ×
Hot pressing under vacuum of 10 ^-5 torr, temperature: 1250-1350 ° C., pressure: 200 kgf / cm ² , holding time: 3 hours, diameter: 300 mm × thickness: 8
mm, and all have an oxygen content of 4.9 to 10% as compared to the theoretical oxygen content as shown in Table 1.
The sintered target materials 1 to 7 of the present invention having a low composition within the range described above were produced.

For the purpose of comparison, the BaTiO ₃ powder was not subjected to the oxygen reduction heat treatment, and (Ba,
Under the same conditions except that the synthesis of Sr) TiO ₃ powder was performed in the air atmosphere and the hot pressing was also performed in the air atmosphere, the conventional sintered target materials 1 to 4 having the compositions shown in Table 1 were manufactured. .

Next, the theoretical density ratios of the various sintered target materials obtained as a result were measured and brazed to an oxygen-free copper backing plate. Substrate temperature: 300 ° C., distance between target substrates: 50 mm, degree of vacuum: 5 × 10 ⁻³ torr, applied power: 1 Kw, sputtering was performed under high power conditions, and the sputtering time until cracks occurred in the target was measured. did.

[0010]

[Table 1]

[0011]

From the results shown in Table 1, since the sintered target materials 1 to 7 of the present invention all have excellent thermal shock resistance, they can be enlarged and sputtered under high power conditions. It is clear that the generation of cracks is remarkably suppressed as compared with the conventional sintered target materials 1 to 4, and it is possible to perform sputtering almost to the limit of use. As described above, the sputtering sintered target material of the present invention is:
It has excellent thermal shock resistance, so it can be made larger, and even when put to practical use under high-power conditions, it shows characteristics that cracking is significantly suppressed, making it fully satisfactory for high-power and labor-saving sputtering equipment. It can respond to.

(56) References JP-A-6-330297 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 C04B 35/42-35 / 49 C01G 25/00-57/00 H01B 3/12

Claims (2)

(57) [Claims] 1. A sputtering sintered target material comprising a composite oxide of Ba and Ti, wherein the Ba and T
A sputtering sintered material having excellent thermal shock resistance, characterized in that the oxygen content of the composite oxide (i) is 4.9 to 10% lower than the theoretical oxygen content of the composite oxide. 2. A sputtering sintered target material comprising a composite oxide of Ba, Sr and Ti, wherein
characterized in that the oxygen content of the composite oxide of a, Sr and Ti is 4.9 to 10% lower than the theoretical oxygen content of the composite oxide. Target material.