JPH0860349A - Sputtering target material for forming ito thin film having high strength and high conductivity - Google Patents

Abstract

PURPOSE: To provide a sputtering target for forming an ITO thin film having high strength and high conductivity. CONSTITUTION: This sputtering target material consists of a four component multiple oxides of In, Sn, Zn and Nb and contains, by weight, 5-20% SnO2 , 0.3-7% ZnO, 0.3-7% Nb2 O3 (where 1-10% ZnO+Nb2 O5 ) and the balance In2 O3 with inevitable impurities when the structural components of the four component multiple oxides are expressed by In2 O3 , SnO2 , ZnO and Nb2 O3 . As a result, the target material showing excellent performance for a long time is obtained.

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 for forming an ITO thin film, which is excellent in strength and conductivity.

[0002]

2. Description of the Related Art In recent years, demand for ITO thin films as liquid crystal displays and electroluminescence, as well as transparent electrodes for solar cells and the like is increasing, and the ITO thin films are composed of a binary oxide compound of In and Sn, and The constituents of the two-component composite oxide are In ₂ O ₃ and S
When represented by nO ₂ , it is well known that it is formed by a sputtering method using a target material containing SnO ₂ : 5 to 20% by weight, and the balance of In ₂ O ₃ and inevitable impurities. is there.

[0003]

On the other hand, in recent years, a sputtering apparatus tends to be large in size, and accordingly, a large target material is required for the sputtering apparatus. However, if it is made large, cracks are likely to occur during sputtering or handling because it does not have sufficient strength, and the film formation rate decreases because it is not satisfactory in terms of conductivity. The problem arises.

[0004]

Therefore, the present inventors have
From the above viewpoints, ITO is excellent in strength and conductivity.
As a result of conducting research to develop a sputtering target material for forming a thin film, the above-mentioned conventional sputtering target material for forming an ITO thin film was made to contain Zn oxide and Nb oxide, and four components of In, Sn, Zn, and Nb were added. When a complex oxide is used, the resulting target material has improved strength and conductivity due to the coexisting action of the Zn oxide and the Nb oxide, and is sufficiently satisfactorily adaptable to increase in size. Is obtained.

The present invention has been made based on the above-mentioned research results, and includes In, Sn, Zn, and Nb.
Of the four-component composite oxide, wherein the constituent components of the four-component composite oxide are In ₂ O ₃ , SnO ₂ , ZnO, and N.
When expressed by a ₂ O _5, it is expressed in% by weight (hereinafter,% means% by weight).
), SnO ₂ : 5 to 20%, ZnO:
0.3 to 7%, Nb ₂ O ₅ : 0.3 to 7% (however,
ZnO + Nb ₂ O ₅ : 1 to 10%) and the balance is a composition consisting of In ₂ O ₃ and inevitable impurities, and is characterized by a sputtering target material for forming an ITO thin film having excellent strength and conductivity. is there.

Next, the reason why the component composition of the target material of the present invention is limited as described above will be explained. (A) SnO ₂ SnO ₂ component has a function of imparting conductivity to the thin film, but if the proportion is less than 5%, desired conductivity cannot be secured, while the proportion exceeds 20%. Since the transparency of the thin film will be impaired, the ratio should be 5
It was set to 20%, preferably 7 to 13%.

(B) ZnO and Nb ₂ O ₅ These components have the function of improving the strength and conductivity of the target material in the coexisting state. Particularly, ZnO is Nb ₂ O 5.
_In the presence of ₅ , it has the effect of refining the crystal grains to improve the strength, and Nb ₂ O ₅ further improves the conductivity.
If the proportion of any of the components is less than 0.3% and the total amount thereof is less than 1%, the desired effect cannot be obtained, whereas the proportion of any component exceeds 7% and the total amount is At 10%
By weight, in particular from becoming as transparency of the thin film is impaired, the content ratio ZnO: 0.3 to 7%, preferably _{0.5~3%, Nb 2 O 5:} 0.3~7 %, Preferably 0.5 to 2%, ZnO + Nb ₂ O ₅ : 1 to 10
%, Preferably 1 to 5%.

[0008]

EXAMPLES The target material of the present invention will be specifically described by way of examples. First, ammonia water is added to a solution of indium nitrate and tin chloride in a predetermined mixing ratio to precipitate hydroxides of In and Sn, which are dried, and then 900 to 12
It is calcined at a predetermined temperature within a range of 00 ° C. for 5 hours, pulverized, and has a purity of 99.9%, and an average particle diameter:
An ITO powder having a particle size of 2 μm and consisting of In ₂ O ₃ and SnO _{2 in a} predetermined ratio was prepared, and this ITO powder had an average particle size of 1 μm and a purity of 99.99% Zn.
O powder and Nb ₂ O ₅ powder were mixed in a predetermined ratio, 0.5% ethanol was added thereto, and the mixture was stirred and mixed for 24 hours in a polypropylene ball mill and dried, and then 400 kg /
Press forming into a green compact with a pressure of cm ²
CIP (cold isostatic press) at a pressure of 500 kgf / cm ²
In the as-molded state, by sintering in an oxidizing atmosphere with an oxygen partial pressure of 600 torr at a predetermined temperature within the range of 1400 to 1600 ° C. for 1.5 hours, the planar dimensions are 18 mm × 18 mm. , Thickness: 6 mm, and the target materials 1 to 7 of the present invention composed of the four-component composite oxide having the composition shown in Table 1 and the conventional target material 1 composed of the two-component composite oxide. ~ 3 were produced respectively. For the various target materials obtained as a result,
Three-point bending strength and specific resistance were measured for the purpose of evaluating strength and conductivity. The results of these measurements are shown in Table 1.

[0009]

[Table 1]

[0010]

From the results shown in Table 1, the target materials 1 to 7 of the present invention are all contained in ZnO and Nb ₂ O ₅ as compared with the conventional target materials 1 to 3 which do not contain these two components. It is clear that it has extremely high strength and conductivity. As described above, since the target material of the present invention has high strength and high conductivity, it can satisfactorily cope with an increase in the size of a sputtering apparatus and exhibit excellent performance over a long period of time.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01B 13/00 503 Z // H01L 21/203 S 9545-4M

Claims (1)

[Claims] 1. A four-component composite oxide of In, Sn, Zn, and Nb, wherein the constituent components of the four-component composite oxide are In ₂ O ₃ , SnO ₂ , ZnO, and Nb ₂ O ₅
When expressed, in _{wt%, SnO 2: 5~20%,} ZnO: 0.3~7
%, Nb ₂ O ₅ : 0.3 to 7% (however, ZnO + Nb ₂
O ₅ : 1 to 10%), and the rest has a composition consisting of In ₂ O ₃ and unavoidable impurities. A sputtering target material for forming an ITO thin film having high strength and high conductivity.