JPH0971860A - Target and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the volume resistivity and to prevent abnormal discharge and production of cracks during forming a film by using a sintered body containing a hexagonal laminar compd. comprising indium oxide and zinc oxide as the target for forming a transparent conductive film. SOLUTION: This target consists of a sintered body of an oxide containing a hexagonal laminar compd. expressed by general formula, In2 O3 (ZnO)m , wherein m is 2 to 7, with 0.2-0.9 atomic ratio of In and Zn calculated as In/(In+Zn) and having <10<-2> Ω.cm volume resistivity. More preferably, an oxide of a third element having tervalent or higher valance selected from the group consisting of Al, Ga, Ge, Sn and Si is incorporated by 20at.% in terms of the whole cation elements into the target. If the third element is Ti, Ti is incorporated by 0.5-10at.%. The target is produced by mixing powders of these oxides of >=99% purity, compacting, sintering at 1,200 to 1,600 deg.C and annealing at 200 to 1,000 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a target and a method for manufacturing the target.

[0002]

2. Description of the Related Art In recent years, the development of display devices has been remarkable, and various display devices such as liquid crystal display devices and EL display devices have been actively introduced into office automation equipment such as personal computers and word processors. Each of these display devices has a sandwich structure in which a display element is sandwiched by a transparent conductive film.

The transparent electrode has a structure in which a transparent conductive film is formed on a transparent substrate. Conventionally, glass was used as the transparent substrate, but with the recent market expansion of portable devices,
Some plastic substrates such as films are used, taking advantage of their lightness and unbreakability.

Usually, the transparent conductive film is formed by a sputtering method using a sintered target. Conventionally, ITO has been used as the target material because the resulting transparent conductive film exhibits high transmittance and low resistance.

[0005]

When a plastic substrate such as a film is used as the film-forming substrate, there is a problem that the temperature during film formation cannot be sufficiently raised and a low resistance film cannot be obtained. It was

On the other hand, recently, a target material that can obtain a low resistance film even on a plastic substrate has been developed. However, this target material has a high volume resistivity and thus a low thermal conductivity, resulting in abnormal discharge during sputtering. However, there is a problem that the target is easily cracked.
It is possible to reduce the volume resistivity to some extent by using a special manufacturing method [HIP (hot isostatic pressing) sintering or normal pressure sintering in an inert gas], but it is possible to use a commercially available high-density ITO target. Compared to this, it is still more than one digit higher, and it cannot be said that the cracking of the target due to abnormal discharge has been improved. Furthermore, the high manufacturing cost makes it unsuitable as a commercial manufacturing method.

Accordingly, a first object of the present invention is to provide a target material which is particularly suitable for forming a film on a plastic substrate such as a film and which is free from abnormal discharge or cracking when the film is used. The purpose of is to provide a method for manufacturing such a target at low cost.

[0008]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned objects, the present inventors have used indium oxide and zinc oxide as raw materials together with an oxide of an element having a valence of positive trivalence or more, if desired. It was found that a target having a volume resistivity of 10 ^-2 Ωcm or less can be obtained by mixing, molding, and sintering the oxide raw materials of 1), and then annealing. In addition, in the target obtained in this way, no abnormal discharge or cracking of the target was observed even when the output was increased during film formation such as sputtering using this target, and it was found that the target life was significantly improved. It was Furthermore, it has been found that the target manufacturing method can obtain the target at a low cost by using an oxide raw material.

The present invention has been completed on the basis of these findings, and (I) the general formula In ₂ O ₃ (ZnO) _m (m
= 2 to 7), the hexagonal layered compound is included, and
The atomic ratio [In / (In + Zn)] of n and Zn is 0.2 to
It consists of a sintered oxide of 0.9 and has a volume resistivity of 1
A target characterized in that it is 0 ^-2 Ωcm or less (hereinafter referred to as target T1), (II) general formula In ₂ O ₃ (Zn
O) _m (m = 2 to 7) represented by a hexagonal layered compound, further containing an oxide of a third element having a valence of positive trivalence of 20 at% or less with respect to all cationic elements, and I
The atomic ratio [In / (In + Zn)] of n and Zn is 0.2 to
It consists of a sintered oxide of 0.9 and has a volume resistivity of 1
A target characterized in that it is 0 ^-2 Ωcm or less (hereinafter referred to as target T2); (III) a step of mixing indium oxide and zinc oxide; a step of molding the mixture obtained in the above step; The method for producing a target according to (I) above, which comprises a step of sintering the molded product obtained in step 1 and a step of annealing the sintered product obtained in the step (hereinafter referred to as production method P1). ), And (I
V) a step of adding an oxide of a third element having a valence of at least positive trivalence to indium oxide and zinc oxide and mixing, a step of molding the mixture obtained in the step, and a step obtained in the step A target manufacturing method (hereinafter referred to as manufacturing method P2) according to (II), which comprises a step of molding and sintering a molded product and a step of annealing the sintered product obtained in the process. Use as a summary.

Hereinafter, the present invention will be described in detail. First, as described above, the target T1 of the present invention includes (i) the general formula In
₂ O ₃ (ZnO) _m (m = 2 to 7) is included, and the atomic ratio of In and Zn [In / (In
+ Zn)] is 0.2 to 0.9, and (ii) the volume resistivity is 10 ⁻² Ωcm or less.

First, the above-mentioned requirement (i) will be explained. A sintered body of an oxide containing a hexagonal layered compound is defined as a substance showing an X-ray diffraction pattern assigned to the hexagonal layered compound by X-ray diffraction measurement. A sintered body of an oxide of the above or a substance showing an X-ray diffraction pattern belonging to a hexagonal layered compound, as well as a substance showing an X-ray diffraction pattern belonging to another structure, and an oxide containing an amorphous substance. Means union.

More specifically, the sintered body contains the hexagonal layered compound in an amount of 5% by weight or more, preferably 10% by weight or more,
More preferably, the content is 20% by weight or more, and the other component is In ₂
It is composed of O ₃ or ZnO, and preferable examples thereof include the following.

(A). In ₂ O ₃ (ZnO) _m (m = 2 to 7)
Hexagonal layered compound (b). A mixture of a hexagonal layered compound of In ₂ O ₃ (ZnO) _m (m = 2 to 7) and In ₂ O ₃ (c). A mixture of a hexagonal layered compound of In ₂ O ₃ (ZnO) _m (m = 2 to 7) and ZnO where In ₂ O ₃ and ZnO in (b) and (c) have a specific crystal structure. ing.

The reason why m is limited to 2 to 7 in the above general formula is that when m exceeds 7, the volume resistivity of the hexagonal layered compound becomes high, and as a result, the volume resistivity of the target becomes high and the target is manufactured. This is because abnormal discharge and cracking of the target are likely to occur when used in the film, and when m is 1, the compound does not become a hexagonal layered compound.

In the target T1 of the present invention, the atomic ratio [In / (In + Zn)] of In and Zn is 0.2 to 0.
It is limited to 9, preferably 0.5 to 0.9, and particularly preferably 0.8 to 0.9. The reason is that if it is less than 0.2, the conductivity of the transparent conductive film obtained from the target is low, and if it exceeds 0.9, the wet heat resistance of the transparent conductive film is lowered.

The above atomic ratio of In and Zn is obtained by adjusting the mixing ratio of indium oxide and zinc oxide before sintering, and the indium oxide and indium oxide matching the stoichiometric ratio can be obtained by the mixing ratio before sintering. It is presumed that a hexagonal layered compound composed of zinc oxide was produced, and the remaining indium oxide and zinc oxide were present as crystalline substances.

The target T1 of the present invention contains the hexagonal layered compound represented by the above-mentioned "general formula In ₂ O ₃ (ZnO) _m (m = 2 to 7), and the atomic ratio of In and Zn [In
/ (In + Zn)] is 0.2 to 0.9, which is a sintered body of an oxide, and a requirement (ii) that "volume resistivity is 10 ^-2 Ωcm or less". Mandatory requirement. This parameter requirement is a new requirement that is first achieved by an annealing treatment after sintering as will be described later, and the target T1 of the present invention has this novel requirement, whereby abnormal discharge and cracking of the target during use of film formation are achieved. Has the remarkable effect of being prevented. The volume resistivity is preferably 7 × 10 ⁻³ Ωcm or less, and 5 × 1 from the viewpoint of preventing abnormal discharge and cracking of the target during film formation.
It is particularly preferably 0 ^-3 Ωcm or less.

The relative density of the sintered body constituting the target T1 of the present invention is preferably 80% or more, more preferably 90% or more, and further preferably 95% or more. When the density of the sintered body is less than 80%, the film forming rate becomes slow, and the target and the film obtained therefrom are likely to be blackened. In order to obtain a sintered body having a high density, it is preferable to perform molding by CIP (cold isostatic pressure) or the like and then sinter by HIP (hot isostatic pressure) or the like. Here, the relative density indicates the actual density of the sintered body with respect to the theoretical density calculated from the composition of the oxide in terms of area fraction.

The target T1 of the present invention contains the hexagonal layered compound represented by the general formula In ₂ O ₃ (ZnO) _m (m = 2 to 7) as described above, and the atomic ratio of In to Zn [[ In / (In + Zn)] has a requirement (i) of being a sintered body of an oxide having a ratio of 0.2 to 0.9,
Excellent conductivity and moisture resistance. Further, since the target T1 of the present invention has the requirement (ii) that the volume resistivity is 10 ^-2 Ωcm or less as described above, there is no problem of abnormal discharge or cracking of the target during film formation using this target. . Therefore, the target T1 of the present invention is suitable as a target for obtaining a transparent conductive film for various uses such as a transparent conductive film for a liquid crystal display element, a transparent conductive film for an EL display element and a transparent conductive film for a solar cell by a sputtering method. is there. When the target T1 of the present invention is used, ITO
It is possible to obtain a transparent conductive film that is more resistant to heat and humidity than the film and has the same conductivity and light transmittance as the ITO film.

The target T1 of the present invention can be manufactured by various methods, but it is preferable to manufacture it by the target manufacturing method P1 of the present invention described later.

Next, the target T2 of the present invention will be described. In this target T2, the oxide sintered body in the target T1 contains the hexagonal layered compound and the third element (for example, A
It differs from the target T1 only in that it contains an oxide of (1, Zr, Ga, Ge, Sn, Ti, Si) in a proportion of 20 at% or less with respect to all the cation elements. In the target T2 of the present invention, the general formula In ₂ O ₃ (ZnO)
_The hexagonal layered compound represented by _m (m = 2 to 7) and the oxide of the third element having a valence of at least positive trivalence are a state in which the oxide of the third element is included in the hexagonal layered compound or The hexagonal layered compound and the oxide of the third element exist in separate states. In the target T2 of the present invention, the reason for limiting the ratio of the third element to the total cation element to 20 at% or less is that when it exceeds 20 at%, ion scattering occurs in the transparent conductive film obtained from this target, and the conductivity becomes low. This is because it is too low. The ratio of the third element is 0.1
15 at% is preferable, and 0.5 to 10 at% is particularly preferable.

Particularly when the third element is titanium, it is extremely preferable that the ratio of titanium to all the cation elements is 0.5 to 10 at%. The reason is that when the ratio of titanium to all the cation elements in the target exceeds 10 at%, the obtained conductive film exhibits a brown color peculiar to titanium oxide, and it becomes difficult to function as a transparent electrode film. . Further, when the proportion of titanium is less than 0.5 at%, it only serves as a sintering aid at the time of conventionally known target sintering, and as will be described later,
This is because the effect of maintaining the resistance uniformity of the conductive film does not appear regardless of the film forming atmosphere. A more preferable ratio of titanium is 1 to 8 at with respect to all cationic elements.
%.

The target T2 of the present invention is the same as the target T1 except that the oxide sintered body forming the target contains the oxide of the third element. Therefore, the following requirement (i) The constituent oxide sintered body contains the hexagonal layered compound represented by the general formula In ₂ O ₃ (ZnO) _m (m = 2 to 7), and the atomic ratio [In / (In
+ Zn)] is 0.2 to 0.9. (Ii) The target has a volume resistivity of 10 ^-2 Ωcm or less. Is an essential requirement.

Regarding the above requirements (i) and (ii),
Since the target T1 has been described in detail, it will not be repeatedly described here, but the target T2 of the present invention satisfies the requirement (i), so that the transparent conductive film obtained has excellent conductivity and wet heat resistance, and the requirement (ii). By satisfying the condition (1), there is no problem of abnormal discharge or cracking of the target when using film formation. Further, unlike the target T1, the target T2 of the present invention contains an oxide of a third element having a valence of positive trivalence or more, and thus the obtained transparent conductive film is more transparent than the transparent conductive film obtained by using the target T1. Also has excellent conductivity.

In particular, when the target T2 of the present invention contains an oxide of titanium (Ti) as the oxide of the third element, the above technical effects and the third effect derived from the requirements (i) and (ii) are obtained. In addition to the above-described technical effect derived from the inclusion of the elemental oxide, a remarkable technical effect that a transparent conductive film having a constant resistance value can be obtained regardless of the fluctuation of the film forming atmosphere. This technical effect will be described in detail below.

Conventionally, the resistance value of the transparent electrode film formed on the plastic substrate is controlled by controlling the oxygen concentration in the atmosphere during film formation, but the oxygen concentration in the atmosphere is controlled. This is a complicated operation that requires extremely high accuracy, and due to the influence of the desorbed gas from the plastic substrate, it is inevitable that the oxygen concentration in the atmosphere will fluctuate. It was hard to say that was obtained with good reproducibility.

On the other hand, when the target T2 of the present invention contains an oxide of titanium, as will be apparent from the examples described later, the target T2 does not substantially depend on the oxygen concentration in the atmosphere during film formation and can be widely used. A transparent conductive film having a uniform and controlled resistance value can be obtained.

That is, when the target T2 of the present invention contains an oxide of titanium, it is not necessary to strictly control the oxygen concentration in the atmosphere during film formation, and the resistance value of the obtained transparent conductive film is not only strictly controlled. Has the dual technical effect of being uniform.

The relative density of the sintered body constituting the target T2 of the present invention is preferably 80% or more, more preferably 90% or more, for the same reason as in the case of the target T1. It is preferably at least 95%.

The target T2 of the present invention is a target for obtaining a transparent conductive film for various uses such as a transparent conductive film for liquid crystal display elements, a transparent conductive film for EL display elements, a transparent conductive film for solar cells, etc. by a sputtering method. It is suitable. Even when this target T2 is used, it is possible to obtain a transparent conductive film which is superior in moisture resistance to the ITO film and has the same conductivity and light transmittance as the ITO film. In particular, the target T2 containing titanium oxide is particularly suitable as a target for obtaining a touch panel electrode film by a sputtering method that requires strict uniformity of resistance.

Although the target T2 can be manufactured by various methods, it is preferably manufactured by the target manufacturing method P2 of the present invention described later.

Next, the manufacturing method P1 and P2 of the target of the present invention will be described. First, the manufacturing method P1 of the present invention for obtaining the target T1 is the step of mixing indium oxide and zinc oxide, the step of molding the mixture obtained in the above step, and the step of sintering the molded article obtained in the above step. And the process of
A step of annealing the sintered product obtained in the above step.

The purity of indium oxide and zinc oxide used as raw materials in the production method P1 is preferably 99% or more, more preferably 99.9% or more, and particularly preferably 99.99% or more. If it is less than 99%, a dense sintered body cannot be obtained even if it is sintered, and the obtained target has a high volume resistivity.

The average particle size of indium oxide and zinc oxide is preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm, and particularly preferably 0.1 to 5 μm.
5 μm. If it is less than 0.01 μm, it easily aggregates.
If it exceeds μm, the mixing property of indium oxide and zinc oxide is poor, and a dense sintered body cannot be obtained even if sintered.

When the particle size of the raw material powder exceeds 10 μm, a ball mill, a roll mill, a pearl mill, a jet mill or the like may be used to adjust the average particle size to fall within the above range.

The mixing step, molding step, sintering step and annealing step will be described below in this order.

(1) Mixing Step Mixing is preferably carried out by placing powders of indium oxide and zinc oxide in a mixer such as a ball mill, jet mill or pearl mill and mixing them. The mixing time is preferably 1 to 100 hours, more preferably 5 to 50 hours.
The time is particularly preferably 10 to 50 hours. If it is less than 1 hour, the mixing is not sufficient, and if it exceeds 100 hours, it is not economical. The mixing temperature is not particularly limited, and room temperature is preferable.

The mixed powder of indium oxide and zinc oxide after mixing may be subjected to a calcination treatment in order to promote the formation of the hexagonal layered compound. The calcination temperature is preferably 800 to 1500 ° C, more preferably 900 to 1400 ° C, and particularly preferably 1000 to 1300 ° C. When the temperature is lower than 800 ° C, a hexagonal layered compound is not formed, and when the temperature exceeds 1500 ° C, indium oxide or zinc oxide is evaporated. Calcination time is 1
100 hours is preferable, more preferably 2 to 50 hours,
Particularly preferably, it is 3 to 30 hours. If it is less than 1 hour, the hexagonal layered compound is not sufficiently formed, and if it exceeds 100 hours, it is not economical.

The calcined product is preferably pulverized so that the particle size is in the range of 0.01 to 10 μm. Grinding is done in the same way as mixing. Moreover, it is better to repeat the calcination and the pulverization in order to promote the formation of the hexagonal layered compound.

The mixed powder of indium oxide and zinc oxide or the calcined powder may be granulated to improve the fluidity and the filling property during molding. Granulation is performed by a conventional method such as a spray dryer. When the spray drying method is used, an aqueous solution of powder or an alcohol solution is used, and polyvinyl alcohol or the like is used as a binder to be mixed with the solution. Granulation conditions vary depending on the solution concentration and the amount of binder added,
The average particle size of the granulated product is 1 to 100 μm, preferably 5 to 1
The thickness is adjusted to 00 μm, particularly preferably 10 to 100 μm. When the average particle size of the granulated product exceeds 100 μm, the fluidity and filling property during molding are poor and the granulation effect is not obtained.

(2) Forming Step The mixed powder of indium oxide and zinc oxide, the calcined powder or the granulated powder is formed by die molding, casting molding, injection molding or the like, but with high sintering density. In order to obtain a body, it is molded by CIP (cold isostatic pressure) or the like. The shape of the molded body can be various shapes suitable as a target. Further, polyvinyl alcohol, methyl cellulose, polywax, oleic acid or the like may be used as a molding aid. The molding pressure is preferably 10 kg / cm ^{2 to} 100 t / cm ² , and more preferably 100 kg / cm ^{2 to} 100 t / cm ² . The molding time is preferably 10 minutes to 10 hours. When the molding pressure is less than 10 kg / cm ² and the molding time is less than 10 minutes, the density of the sintered body obtained after sintering cannot be increased.

(3) Sintering Step Sintering of the molded product is preferably performed by normal pressure firing. Other sintering methods include HIP (hot isostatic pressing) sintering and hot press sintering, but atmospheric pressure sintering is superior in terms of economy.

The sintering temperature is preferably 1200 to 1600 ° C, more preferably 1250 to 1550 ° C, and further preferably 1300 to 1500 ° C. If the temperature is less than 1200 ° C., the hexagonal layered compound In ₂ O ₃ (ZnO) _m (m = 2 to 7)
Is not generated and indium oxide or zinc oxide is sublimated at a temperature higher than 1600 ° C., compositional deviation occurs, or _m of hexagonal layered compound In ₂ O ₃ (ZnO) _m generated is larger than 7 and obtained. The volume resistivity of the sintered body increases.

Although the sintering time depends on the sintering temperature, it is 1 to 50.
The time is preferably, more preferably 2 to 30 hours, particularly preferably 3 to 20 hours. If it is less than 1 hour, the formation and sintering of the hexagonal layered compound are not sufficiently performed, and if it exceeds 50 hours, it is not economical. The atmosphere during sintering is air or a reducing atmosphere. Examples of the reducing atmosphere include reducing gas atmospheres such as H ₂ , methane and CO, and inert gas atmospheres such as Ar and N ₂ .

(4) Annealing Step This annealing step is an essential step for lowering the volume resistivity of the sintered product obtained in the previous step and obtaining a target having a volume resistivity of 10 ^-2 Ωcm or less. Yes, this is a characteristic step in the manufacturing method P1 of the present invention. This annealing step is performed in a furnace such as a sintering furnace or a hot press reduction furnace in a vacuum or a reducing atmosphere.

As the reducing atmosphere, H ₂ , methane, CO
Examples of the atmosphere include a reducing gas such as Ar and N, an inert gas such as Ar and N ₂ . The annealing temperature is preferably 200 to 1000 ° C, more preferably 300 to 1000 ° C, and further preferably 400 to 1000 ° C. If it is less than 200 ° C, sufficient reduction is not carried out, and if it exceeds 1000 ° C, it is not economical. The annealing time is preferably 1 to 50 hours, more preferably 2 to 30 hours, and further preferably 3 to 20 hours. In less than 1 hour, sufficient reduction is not performed
It is not economical when it exceeds time.

The annealing temperature for annealing in vacuum is preferably 200 to 1000 ° C.,
More preferably 200 to 700 ° C., still more preferably 20.
0-500 ° C. If the temperature is lower than 200 ° C., sufficient reduction is not performed, and if the temperature exceeds 1000 ° C., ZnO or In ₂ O _{3 in} the sintered body is evaporated, resulting in a composition shift. When annealing is performed in vacuum, the time is 1 to 5 as above.
It is preferably 0 hours, more preferably 2 to 30 hours, further preferably 3 to 20 hours.

The color of the sintered body after the annealing treatment becomes blacker than that before the annealing.

By this annealing treatment, the target T1 of the present invention having a volume resistivity of 10 ^-2 Ωcm or less and free from problems such as abnormal discharge and cracking during the use of film formation can be obtained.
The target T1 obtained by the manufacturing method P1 has a volume resistivity of 1
It is 0 ^-2 Ωcm or less, which solves the above-mentioned problems of abnormal discharge and cracking of the target, and the sintered body of the oxide constituting the target has a general formula of In ₂ O ₃ (ZnO) _m (m =
2 to 7) containing a hexagonal layered compound, and In and Z
The atomic ratio [In / (In + Zn)] of n is 0.2 to 0.9.
Therefore, it is already described that the transparent conductive film obtained by using this target is excellent in conductivity and resistance to moist heat.

Next, the manufacturing method P2 of the present invention will be described. The manufacturing method P2 of the present invention for obtaining the target T2 is described above only in the point that a mixture of indium oxide and zinc oxide is mixed with an oxide of a third element having a valence of positive trivalence or more to obtain a mixture. Basically, the manufacturing method is different from the manufacturing method P1 except that the manufacturing method P1 is the same.

Therefore, only the point of using the oxide of the third element as the raw material will be described in detail, and the mixing step, molding step,
The description of the sintering process and the annealing process is omitted.

The oxide of the third element used together with indium oxide and zinc oxide as a raw material in the manufacturing method P2 is an oxide of an element having a valence of positive trivalence or more, and specific examples thereof include Al, Zr, Ga, Ge, Sn, Ti, S
Examples thereof include oxides such as i.

The purity of the oxide of the third element is preferably 99% or more, more preferably 99.9% or more, and particularly preferably 99.99% or more. If it is less than 99%, a dense sintered body cannot be obtained even if it is sintered, and problems such as high volume resistivity of the obtained target occur.

The average particle size of the oxide of the third element is 0.
01 to 10 μm is preferable, and more preferably 0.05 to
It is 5 μm, particularly preferably 0.1 to 5 μm. 0.01
If it is less than μm, it tends to aggregate, and if it exceeds 10 μm, the mixing property is poor, and a dense sintered body cannot be obtained even if it is sintered. In addition,
If the particle size of the raw material powder exceeds 10 μm, use a ball mill, roll mill, pearl mill, jet mill, etc.
It can also be used by adjusting so that the average particle diameter falls within the above range.

The amount of the oxide of the third element added to indium oxide and zinc oxide is determined so that the content of the third element is 20 at% or less with respect to all the cation elements in the obtained target. The reason is that, as described above, when the ratio of the third element to all the cation elements in the target exceeds 20 at%, scattering of ions occurs in the transparent conductive film obtained from the target, resulting in too low conductivity. .

The amount of the third element oxide added is such that the ratio of the third element to all the cation elements in the target is 0.
The amount is preferably 1 to 15 at%, 0.5 to 1
An amount of 0 at% is particularly preferable.

Particularly when titanium oxide is used as the third element oxide, the amount of titanium oxide added is 0.5 to 10 at% of titanium with respect to all the cation elements in the obtained target. Is highly preferred. The reason why the above range is extremely preferable as the amount of titanium oxide added is that, as described above, when the ratio of titanium to the total cation elements is in the range of 0.5 to 10 at%, the resistance is independent of the film forming atmosphere. The reason is that a uniform transparent conductive film can be obtained. The amount of titanium oxide added is more preferably 1 to 8 at% of titanium with respect to all cationic elements.

The target T2 obtained by the manufacturing method P2 is
As described above, the sintered body of the oxide constituting the target contains the hexagonal layered compound represented by the general formula In ₂ O ₃ (ZnO) _m (m = 2 to 7) and is composed of In and Zn. Since it also has a requirement that the atomic ratio [In / (In + Zn)] is 0.2 to 0.9, the transparent conductive film obtained from this target has excellent conductivity and wet heat resistance. Further, since the oxide of the third element having a valence of positive trivalence or more is contained so that the ratio of the third element is 20 at% or less with respect to all the cation elements, the obtained transparent conductive film uses the target T1. It is superior in conductivity to the transparent conductive film obtained by the above. Furthermore, since the volume resistivity is 10 ^-2 Ωcm or less,
It has an advantage that there is no problem of abnormal discharge or cracking of the target when the film is used.

The target T2 obtained by the manufacturing method P2
However, when a titanium oxide is contained as the oxide of the third element, a transparent conductive film having excellent resistance uniformity can be obtained without being substantially affected by the oxygen concentration in the atmosphere during the formation of the transparent conductive film. Has the advantage.

[0060]

EXAMPLES The present invention will be further described with reference to the following examples. The composition analysis method, the crystal structure confirmation method, the volume resistivity measurement method, and the abnormality when the target was used for film formation were used in the examples in advance. The method of observing discharge and target cracking will be described.

<Composition analysis> S manufactured by Seiko Instruments Inc.
It was performed by ICP analysis (inductively coupled plasma optical emission spectroscopy) using PS-1500VR.

<Confirmation of Crystal Structure> This was carried out using an X-ray diffraction measuring device manufactured by Rigaku Corporation.

<Measurement method of volume resistivity> 20 mm × 40 mm
A test piece of a sintered body of × 5 mm was prepared and measured by the 4-terminal method.

<Method of Observing Abnormal Electric Discharge and Crack when Using Target Film Formation> Film formation was performed with a DC sputtering apparatus at 5 W / cm ² using a 4-inch target, and the presence or absence of abnormal discharge and the presence or absence of cracks in the target were observed. .

(Target production example 1) Purity 99.99%
Oxide powder (average particle size 1 μm) 260 g and zinc oxide powder with a purity of 99.99% (average particle size 1 μm) 40
g was put in a polyimide pot together with ethanol and alumina balls, and mixed for 2 hours with a planetary ball mill. Put the resulting mixed powder in a mold and press the mold press machine for 100kg.
Preforming was performed at a pressure of / cm ² . Next, the product was consolidated with a cold isostatic press molding machine at a pressure of 4 t / cm ² , and then sintered in an air atmosphere at 1300 ° C. for 4 hours in a sintering furnace. The obtained sintered body is further subjected to 2 at 500 ° C. in a vacuum using a vacuum sintering furnace.
Annealed by heat treatment for a period of time. When the crystal structure of the obtained sintered body was measured by X-ray diffraction, In ₂ O ₃ (Z
Formation of a hexagonal layered compound of nO) ₃ and In ₂ O ₃ was observed. Further, when the composition was analyzed by ICP analysis, the atomic ratio In / (In + Zn) was 0.80.
The density of the sintered body was 95%.

(Target production example 2) Purity 99.99%
Oxide powder (average particle size 1 μm) 260 g and zinc oxide powder with a purity of 99.99% (average particle size 1 μm) 40
g was put in a polyimide pot together with ethanol and alumina balls, and mixed for 2 hours with a planetary ball mill. The obtained mixed powder was fired at 1000 ° C. for 5 hours and then mixed again for 2 hours with a planetary ball mill. The obtained mixed powder was put into a mold and pre-molded by a mold press molding machine at a pressure of 100 kg / cm ² . Next, with a cold isostatic press molding machine, 4t
1) in a sintering furnace in an air atmosphere after consolidation at a pressure of / cm ²
Sintered at 300 ° C. for 4 hours. The obtained sintered body was annealed by further heat-treating it in vacuum at 500 ° C. for 2 hours using a vacuum sintering furnace. When the crystal structure of the obtained sintered body was measured by X-ray diffraction, formation of In ₂ O ₃ (ZnO) ₃ hexagonal layered compound and In ₂ O ₃ were confirmed. Also, ICP
When the composition analysis was performed by analysis, the atomic ratio In / (I
n + Zn) was 0.81. Also, the density of the sintered body is 9
5%.

(Target production example 3) Purity 99.99%
Oxide powder (average particle size 1 μm) 260 g and zinc oxide powder with a purity of 99.99% (average particle size 1 μm) 40
g was put in a polyimide pot together with ethanol and alumina balls, and mixed for 2 hours with a planetary ball mill. The obtained mixed powder was fired at 1000 ° C. for 5 hours and then mixed again for 2 hours with a planetary ball mill. Water and polyvinyl alcohol were added to the obtained mixed powder, and after mixing, the mixture was granulated with a spray dryer. The obtained granulated product was a spherical powder having an average particle size of 10 μm. The obtained granulated powder was put in a mold and pre-molded by a mold press molding machine at a pressure of 100 kg / cm ² . Next, after compacting with a pressure of 4 t / cm ² by a cold isostatic press molding machine, 1300 ° C. in an air atmosphere in a sintering furnace.
Sintered for 4 hours. The obtained sintered body was annealed by further heat-treating it in vacuum at 500 ° C. for 2 hours using a vacuum sintering furnace. When the crystal structure of the obtained sintered body was measured by X-ray diffraction, formation of In ₂ O ₃ (ZnO) ₃ hexagonal layered compound and In ₂ O ₃ were confirmed. In addition, when the composition was analyzed by ICP analysis, the atomic ratio In / (In + Z
n) was 0.81. The density of the sintered body was 97%.

(Target production example 4) Purity 99.99%
254 g of indium oxide powder (average particle size 1 μm) and zinc oxide powder with a purity of 99.99% (average particle size 1 μm) 39
g and 99.99% purity tin oxide powder (average particle size 1μ
m) 7 g was put into a polyimide pot together with ethanol and alumina balls, and mixed for 2 hours with a planetary ball mill.
The obtained mixed powder is put into a mold, and the mixture is pressed with a mold press molding machine.
Preforming was performed at a pressure of 00 kg / cm ² . Next, the product was consolidated with a cold isostatic press molding machine at a pressure of 4 t / cm ² , and then sintered in an air atmosphere at 1300 ° C. for 4 hours in a sintering furnace. The obtained sintered body is vacuumed at 500 ° C. in a vacuum sintering furnace.
Then, it was annealed by further heat-treating for 2 hours. The crystal structure of the obtained sintered body was measured by X-ray diffraction.
The formation of hexagonal layered compound of ₂ O ₃ (ZnO) ₃ and In ₂ O ₃ was observed. Further, when the composition was analyzed by ICP analysis, the atomic ratio In / (In + Zn) was 0.80. The ratio of Sn to all cation elements is 4 at
%Met. The sintered body density was 95%.

Table 1 shows the crystal structure, composition and sintered body density of the targets obtained in the above Target Production Examples 1 to 4.

[0070]

[Table 1]

Target Production Examples 5 to 16 Target Production Examples 1 to 1 as shown in Table 2 except that a predetermined amount of In ₂ O ₃ , ZnO and a third element oxide were used as shown in Table 2.
A target was manufactured by using any one of the methods of 4 above. Table 2 shows the amount of raw materials used, the production method, and the physical properties of the target.

[0072]

[Table 2]

(Comparative Target Production Example 1) Purity 99.9
30 g of 9% indium oxide powder (average particle size 1 μm) and 99.99% pure zinc oxide powder (average particle size 1 μm) 2
70 g of ethanol and alumina balls were put in a polyimide pot and mixed for 2 hours with a planetary ball mill. The obtained mixed powder is put into a mold, and is pressed by a mold press molding machine.
Preforming was performed at a pressure of 0 kg / cm ² . Next, the product was consolidated with a cold isostatic press molding machine at a pressure of 4 t / cm ² , and then sintered in an air atmosphere at 1300 ° C. for 4 hours in a sintering furnace. The obtained sintered body is vacuumed at 500 ° C. in a vacuum sintering furnace.
Then, it was annealed by further heat-treating for 2 hours. The crystal structure of the obtained sintered body was measured by X-ray diffraction.
Formation of hexagonal layered compounds of ₂ O ₃ (ZnO) ₅ and In ₂ O ₃ (ZnO) ₇ and In ₂ O ₃ was observed. Also, IC
When the composition was analyzed by P analysis, the atomic ratio In /
(In + Zn) was 0.15. The density of the sintered body was 95%.

(Comparative Target Production Example 2) Purity 99.9
260 g of 9% indium oxide powder (average particle size 1 μm)
And 99.99% pure zinc oxide powder (average particle size 1 μm)
40 g was put in a polyimide pot together with ethanol and alumina balls, and mixed for 2 hours with a planetary ball mill. The obtained mixed powder is put into a mold, and is pressed by a mold press molding machine.
Preforming was performed at a pressure of 0 kg / cm ² . Next, the product was consolidated with a cold isostatic press molding machine at a pressure of 4 t / cm ² , and then sintered in an air atmosphere at 1300 ° C. for 4 hours in a sintering furnace. In this comparative example, the sintered product was not annealed. When the crystal structure of the obtained sintered body was measured by X-ray diffraction, formation of In ₂ O ₃ (ZnO) ₃ hexagonal layered compound and In ₂ O ₃ were confirmed. In addition, when the composition was analyzed by ICP analysis, the atomic ratio In / (In + Z
n) was 0.80. The density of the sintered body was 95%.

(Comparative Target Production Example 3) Purity 99.9
260 g of 9% indium oxide powder (average particle size 1 μm)
And 99.99% pure zinc oxide powder (average particle size 1 μm)
40 g was put in a polyimide pot together with ethanol and alumina balls, and mixed for 2 hours with a planetary ball mill. The obtained mixed powder is put into a mold, and is pressed by a mold press molding machine.
Preforming was performed at a pressure of 0 kg / cm ² . Next, after cold-pressing with a cold isostatic press molding machine at a pressure of 4 t / cm ² , it was sintered in an air atmosphere at 1700 ° C. for 4 hours in a sintering furnace. Further, the obtained sintered body is heated in vacuum using a vacuum firing furnace.
Further heat treatment was performed at 0 ° C. for annealing. The crystal structure of the obtained sintered body was measured by X-ray diffraction, an In ₂
A hexagonal layered compound of O ₃ (ZnO) _m (m = 9) and In
Formation of ₂ O ₃ was observed. Further, when the composition was analyzed by ICP analysis, the atomic ratio In / (In + Zn) was 0.70. The density of the sintered body was 94%.

Table 3 shows the amounts of the raw materials used and the physical properties of the targets in Comparative Target Production Examples 1 to 3.

[0077]

[Table 3]

(Note) In Comparative Production Example 1, In / (In + Zn) = 0.15 in the obtained target, which is outside the scope of the present invention.

In Comparative Production Example 2, since the annealing step was not performed, the volume resistivity exceeded 10 ^-2 Ωcm as shown in Table 4 below, which is outside the range of the present invention.

In Comparative Production Example 3, In ₂ O ₃ (Zn
O) _m = 9 in m, which is outside the scope of the present invention.

(Test Example) 20 sintered bodies produced in Target Production Examples 1 to 16 and Comparative Target Production Examples 1 to 3 were produced.
mm × 40 mm × 5 mm was cut out, and the volume resistivity was measured by the four-terminal method. The results are shown in Table 4.

Further, in the same manner as in Target Production Examples 1 to 16 and Comparative Target Production Examples 1 to 3, 4 inches φ ×
A 5 mm circular sintered body was manufactured, and a sputtering target was prepared by using a copper packing plate and indium metal as a bonding material.

Using this sputtering target, the life of the target was evaluated by the DC sputtering method at an output of 5 W / cm ² . The results are shown in Table 4.

[0084]

[Table 4]

As is clear from Table 4, the targets obtained in Target Production Examples 1 to 16 all had a volume resistivity of 10 ^-2 Ωcm or less, and abnormal discharge and cracking of the target were observed during film formation. There wasn't.

On the other hand, the targets obtained in Comparative Production Examples 1 to 3 all have a volume resistivity of more than 10 ^-2 Ωcm,
Abnormal discharge and cracking of the target were observed 20 to 30 hours after using the film.

The transparent conductive films obtained by using the targets obtained in Production Examples 1 to 16 were excellent in conductivity and wet heat resistance.

(Target Production Example 17) As raw material oxide powders to be mixed, 254 g of In ₂ O ₃ powder having a purity of 99.99% (average particle size 1 μm) and zinc oxide powder having a purity of 99.99% (average particle size 1 μm) ) 40 g, and purity 99.99
A target was manufactured in the same manner as in Target Manufacturing Example 1 except that 6 g of titanium oxide powder (average particle diameter 1 μm) of 6% was used. When the crystal structure of the obtained sintered body was measured by X-ray diffraction, only the hexagonal layered compound of In ₂ O ₃ (ZnO) ₃ and In ₂ O ₃ were found to be formed. In addition, when the composition was analyzed by ICP analysis, the atomic ratio [In / (In
+ Zn)] was 0.79. Also, the density of the sintered body is 9
The volume resistivity was 6% and the volume resistivity was 0.22 × 10 ^-2 Ω · cm.

(Film Forming Example) Target Using the In ₂ O ₃ —ZnO—TiO ₂ type target obtained in Manufacturing Example 17, a transparent electrode film was formed under the conditions shown in Table 5.

[0090]

[Table 5]

Under the above conditions, the oxygen concentration in the introduced gas was changed to obtain a transparent electrode film having a film thickness of 800 to 1000 Å. Table 6 shows the oxygen partial pressure dependence of the specific resistance of the transparent electrode film thus obtained.

For comparison, using the In ₂ O ₃ (ZnO) -based target obtained in Target Comparative Production Example 3, the same film formation and evaluation as the method described in the above film formation example were carried out. Shown in.

[0093]

[Table 6]

As is clear from Table 6, the transparent electrode film obtained by forming the target obtained in Target Production Example 17 had a specific resistance of 20.2 to 0 in the oxygen concentration range of 0 to 10%.
It is in the range of 21.8 × 10 ⁻⁴ Ω · cm, and a stable and uniform conductive film can be obtained without strict control of the oxygen concentration and the flow of the introduced gas.

On the other hand, the transparent electrode film obtained by forming the target obtained in Comparative Example 3 for target production had an oxygen concentration of 0.
The specific resistance is 5.3 to 35.5 × 10 ^-4 Ω in the range of -10%
Since it varies up to cm, it is necessary to strictly control the oxygen concentration and the flow of introduced gas in order to obtain a stable and uniform conductive film.

Therefore, when the target of the present invention containing titanium oxide is used, it is possible to easily produce a transparent conductive film for display materials and a touch panel input device electrode film which are required to have a uniform resistance.

[0097]

According to the present invention, not only is the transparent conductive film obtained by use for film formation excellent in conductivity and resistance to moist heat, but there is no abnormal discharge or cracking during the use of the film and its production. A method was provided.

Further, according to the present invention, by using titanium oxide as the oxide of the third element, it is possible to easily obtain a transparent conductive film having a uniform and stable resistance value on a plastic substrate such as a film. And a method for manufacturing the same.

Claims (11)

[Claims] 1. The general formula In ₂ O ₃ (ZnO) _m (m = 2 to
7) containing the hexagonal layered compound and containing In and Z
The atomic ratio [In / (In + Zn)] of n is 0.2 to 0.9.
Made of a sintered oxide of oxide with a volume resistivity of 10 ^-2 Ω
A target characterized by being less than or equal to cm. 2. The general formula In ₂ O ₃ (ZnO) _m (m = 2 to
7) which includes a hexagonal layered compound, further contains an oxide of a third element having a valence of positive trivalence of 20 at% or less with respect to all cationic elements, and has an atomic ratio of In to Zn [In / (In + Zn)] is 0.2 to 0.9, which is a sintered body of an oxide, and has a volume resistivity of 10 ^-2 Ωcm or less. 3. The target according to claim 2, wherein the third element is selected from the group consisting of aluminum, zirconium, gallium, germanium, tin and silicon. 4. The target according to claim 2, wherein the third element is titanium. 5. The target according to claim 4, wherein the composition ratio of titanium is 0.5 to 10 at% with respect to all cationic elements. 6. A step of mixing indium oxide and zinc oxide, and a step of molding the mixture obtained in the above step,
The method for manufacturing a target according to claim 1, comprising a step of sintering the molded product obtained in the step, and a step of annealing the sintered product obtained in the step. 7. A step of adding to and mixing indium oxide and zinc oxide with an oxide of a third element having a valence of positive trivalence or higher, and a step of molding the mixture obtained in the step.
The method for producing a target according to claim 2, comprising a step of molding and sintering the molded product obtained in the step, and a step of annealing the sintered product obtained in the process. 8. The method according to claim 6, wherein the purity of the oxides of indium oxide, zinc oxide and the third element used as the raw material is 99% or more. 9. The method according to claim 6, wherein in the mixing step, indium oxide and zinc oxide are mixed together with an oxide of the third element, if necessary, and then calcination treatment and / or granulation treatment is performed. 10. The method according to claim 6, wherein the sintering step is performed at a temperature of 1200 to 1600 ° C. 11. The annealing process is performed in the range of 200 to 1000.
The method according to claim 10, which is carried out at a temperature of ° C.