KR20020013535A - Sputtering target and production method therefor - Google Patents

Abstract

IZO sputtering target for forming a transparent conductive film mainly composed of In and Zn oxides containing 100 to 2000 ppm of Sn, and 100 to 2000 ppm of Sn, so that ZnO is 0.5 to 25% by weight in a method for producing ₂ O ₃ ZnO and IZO sputtering for forming a transparent conductive film composed mainly of an oxide of in and Zn and sintering the powder mixture at 1100~1500 ℃ a target.

The IZO transparent conductive film mainly composed of In and Zn oxides can be improved without losing the properties of the IZO transparent conductive film. The addition of a very small amount of Sn can reduce the bulk resistance and ensure stable discharge in the sputtering target. The IZO sputtering target for transparent conductive film formation and this transparent conductive film can be obtained stably and reproducibly.

Description

Sputtering target and its manufacturing method {SPUTTERING TARGET AND PRODUCTION METHOD THEREFOR}

Since the transparent conductive film made of several metal complex oxides has high conductivity and visible light transmittance, condensation of a liquid crystal display device, a thin film electroluminescence display device, a radiation detection device, a transparent plate of a terminal device, and window glass (I) It is used for various uses, such as a heating film for prevention, an antistatic film or a selective permeable membrane for a solar collector, and an electrode for a touch panel.

The most prevalent among the transparent conductive films made of such metal complex oxides is a transparent conductive film made of indium oxide-tin oxide called ITO.

In addition, indium oxide-zinc oxide, the thing which added antimony to tin oxide, the thing which added aluminum to zinc oxide, etc. are known. Since they are easy to manufacture, price, characteristics, etc. differ, they are used suitably according to the use.

Among them, it has been proposed to use a transparent conductive film mainly composed of In and Zn oxides (IZO) having a larger etching rate than the ITO film. However, since IZO has a higher bulk resistance value than ITO, in the DC magnetron sputtering process, discharge during sputtering may become unstable in particular.

In an indium oxide type sintered compact, it is known that bulk resistance falls by adding about 5% of tin, and this effect is acquired also in indium oxide-zinc oxide.

However, the addition of a large amount of tin is separated from the IZO component system containing the oxides of In and Zn as a main component, and a substantially different type of In-Zn-Sn oxide oxide (ITZO) transparent conductive film is formed. It becomes to manufacture.

Therefore, since the characteristic which the IZO transparent conductive film which has the oxides of In and Zn as a main component loses, it is hard to say that it necessarily meets the objective.

The present invention relates to an IZO sputtering target for forming a transparent conductive film mainly composed of oxides of In and Zn having a low bulk resistance, and a method of manufacturing the same.

1 is a graph showing the relationship between the bulk resistance value and the Sn content of an IZO sputtering target, which is an example and a comparative example mainly composed of oxides of In and Zn,

2 is a graph showing the relationship between the bulk resistance value and Sn content measured up to 100000 ppm of Sn content by logarithmic scale.

In view of the above, the present invention aims to improve without losing the characteristics of the IZO transparent conductive film mainly composed of In and Zn oxides, and by adding a very small amount of Sn, the bulk resistance value is lowered in sputtering. Provided are an IZO sputtering target for forming a transparent conductive film that can be stably discharged, and a method for producing an IZO sputtering target for forming a transparent conductive film which can stably and reproducibly obtain the transparent conductive film.

That is, the present invention

(1) In and Zn oxides containing from 100 to 2000 ppm of Sn;

IZO sputtering target for forming a transparent conductive film as a main component,

(2) In and Zn oxides containing from 100 to 1000 ppm of Sn;

IZO sputtering target for forming a transparent conductive film as a main component,

(3) In and Zn oxides containing from 100 to 500 ppm of Sn

IZO sputtering target for forming a transparent conductive film mainly containing

(4) Each of (1) to (3), characterized in that the bulk resistance is 1 to 5 mΩ · cm.

IZO sputtering target for transparent conductive film formation described,

(5) The content of unavoidable impurities such as Fe, Al and Si should be less than 10 ppm each.

For transparent conductive film formation as described in each of (1)-(4) characterized by the above-mentioned.

IZO sputtering targets,

(6) In each of (1) to (5), wherein the crystal grain size is 4 µm or less.

IZO sputtering target for transparent conductive film formation described,

(7) The crystal grain diameter is 3 µm or less, each of (1) to (6) described in the above.

IZO sputtering target for forming a transparent conductive film,

(8) Crystal grain size is 2 micrometers or less, It is characterized by each of (1)-(7) characterized by the above-mentioned.

IZO sputtering target for forming a transparent conductive film,

(9) In ₂ O ₃ containing from 100 to 200 ppm of Sn and ZnO to 0.5 to 25% by weight;

And a powder mixed with ZnO are sintered at 1100 to 1500 ° C.

Is an IZO spur for forming a transparent conductive film mainly composed of oxides of In and Zn.

Manufacturing method of the turing target,

(10) In according to (9), characterized in that it contains 10 to 100 ppm Sn.

IZO sputtering target for forming a transparent conductive film mainly composed of Zn oxide

Manufacturing method

(11) In and Zn of (9), characterized in that it contains 100 to 500 ppm of Sn.

IZO sputtering target for forming a transparent conductive film mainly composed of oxide of

Manufacturing method

To provide.

(Embodiment of invention)

In the production of sputtering targets containing oxides of In and Zn as main components, for example, indium oxide powder having an average particle diameter of 2 µm and zinc oxide powder having a particle size of approximately 90: 10 are present in a weight ratio. It is weighed as much as possible, and 100 to 2000 ppm of tin, preferably 100 to 1000 ppm, more preferably 100 to 500 ppm of tin and a molding binder are added and mixed uniformly.

Next, this mixed powder is filled into a mold and pressure molded, and then sintered for 0 to 20 hours at a high temperature of 1100 to 1500 ° C. The crystal grain size of the IZO sputtering target sintered compact is 4 µm or less, preferably 3 µm or less, and more preferably 2 µm or less.

The IZO sputtering target sintered compact thus obtained is ground by a plane grinding machine to obtain an IZO target material having a surface roughness Ra of 5 µm or less.

Here, the sputter surface of the IZ0 sputtering target may be subjected to mirror surface processing, and the average surface roughness Ra may be 1000 angstroms or less.

This mirror surface finishing (polishing) can use the well-known polishing technique, such as mechanical polishing, chemical polishing, and mechanochemical polishing (combination of mechanical polishing and chemical polishing).

For example, after polishing with a fixed abrasive polisher (polisher liquid: water) to ＃ 2000 or more, or lapping with a glass abrasive wrap (abrasive: SiC paste, etc.), the abrasive is converted into a diamond paste for lapping. It can be obtained by. There is no particular limitation on this polishing method, and other polishing methods may be employed as long as the average surface roughness Ra of the present invention can be obtained. The obtained IZO sputtering target is bonded to a backing plate.

Next, a clean process such as air blow or running water washing is performed. When the foreign matter is removed by the air blow, it is possible to remove it more efficiently by performing intake with a dust collector on the opposite side of the nozzle. However, since there is a limit in the above air blow and running water cleaning, ultrasonic cleaning is performed again. This ultrasonic cleaning is effective by performing multiple oscillations at a frequency of 25 to 300 KHz. For example, ultrasonic cleaning may be performed by multiple oscillation of 12 kinds of frequencies every 25 KHz between frequencies of 25 to 300 KHz.

The bulk resistance value of the IZO sputtering target for transparent conductive film formation thus formed can be controlled in the range of 1-5 m (ohm) * cm.

As described above, it is possible to lower the bulk resistance value of the IZO sputtering target with a small amount of Sn content of 2000 ppm or less without almost converting the component system of IZO.

IZO which is mainly composed of oxides of In and Zn containing Sn of 100 to 2000 ppm, preferably 100 to 1000 ppm, more preferably l00 to 500 ppm by sputtering using an IZO sputtering target after bonding. Make a transparent conductive film. As a result, a transparent conductive film having a specific resistance of 1.0 × 10 ^-4 to 1.0 × 10 ^-3 Ωcm can be obtained.

(Examples and Comparative Examples)

Next, an Example demonstrates this invention, comparing with a comparative example.

In the preparation of the IZO sputtering target, first, an indium oxide powder having an average particle diameter of 2 µm, zinc oxide powder and tin (Sn) having the same particle size were weighed in the ratios shown in Table 1, and then a molding binder was added and uniformly added. It was mixed and granulated.

Next, this raw material mixture was uniformly filled in a mold and pressure-molded with a cold press. The molded product thus obtained was sintered at 1430 ° C. for 7 hours by a sintering furnace. The surface of the sintered compact thus obtained was ground with a plane grinding machine, and the side edges were cut with a diamond cutter to obtain an IZO target material.

The density of this IZO target material was 6.90 g / cm ³ and the average grain size was 1.5 μm.

Sample No. Sn (ppm) Bulk resistance In ₂ O ₃ (wt%) ZnO (wt%) One 0 5.28 89.3 10.7 2 0 4.97 89.3 10.7 3 0 4.37 89.3 10.7 4 0 4.86 89.3 10.7 5 179 4.11 89.3 10.7 6 179 4.11 89.3 10.7 7 179 4.19 89.3 10.7 8 179 4.57 89.3 10.7 9 210 3.32 89.3 10.7 10 210 3.76 89.3 10.7 11 210 3.31 89.3 10.7 12 210 3.39 89.3 10.7 13 210 3.24 89.3 10.7 14 210 3.2 89.3 10.7 15 210 3.69 89.3 10.7 16 345 2.79 89.3 10.7 17 345 2.59 89.3 10.7 18 345 2.8 89.3 10.7 19 345 2.78 89.3 10.7 20 345 2.79 89.3 10.7 21 345 2.57 89.3 10.7 22 345 2.73 89.3 10.7 23 345 2.39 89.3 10.7 24 345 2.68 89.3 10.7 25 345 2.52 89.3 10.7 26 345 2.92 89.3 10.7 27 345 2.72 89.3 10.7 28 2100 1.88 89.3 10.4 29 2700 1.66 89.3 10.4 30 3400 1.73 89.3 10.3 31 3400 1.66 89.3 10.3 32 39000 0.72 89.3 5.7 33 78800 0.14 90 0

Next, the surface was blown with air, and 12 kinds of frequencies were oscillated every 25 KHz between frequencies of 25 to 300 KHz, and ultrasonic cleaning was performed for 3 minutes. It dried after that and obtained the IZO sputtering target of the Example of this invention and a comparative example.

As shown in Table 1, Samples 1 to 4 were free of tin (Sn) (Comparative Example), Samples 5 to 8 added 179 ppm of Sn (Example), and Samples 9 to 15 were 210 ppm of Sn. The added (Example), and the samples 16-27 added 345 ppm of Sn (Example), and the samples 28-31 show the addition of 2100-3400 ppm of Sn (comparative example).

However, samples 32 and 33 added 39000 and 78800 ppm of Sn (comparative example), and the addition amount was changed, keeping the sum total of Zn + Sn unchanged. In addition, when Sn is added in excess of 2000 ppm, the properties of IZO are lost, which is not suitable for the purposes of the present invention.

Table 1 shows the measurement results of the bulk resistance values of the IZO sputtering target. In addition, in order to make this data easy to see, graphing is shown in FIG. 1 and FIG.

Figure 1 plots the data from no addition of Sn to 345 ppm addition, and Figure 2 plots the bulk resistance values of 179 ppm addition to 78800 ppm addition of Sn (omission of no addition in Fig. 2). Is represented by the logarithmic scale)

As shown in Table 1 and FIG. 1, the addition of 179 ppm to 345 ppm of Sn has a low bulk resistance value since the bulk resistance is in the range of 1 to 5 mΩ · cm (1 to 5 × 10 ⁻³ Ω · cm). Indicates.

On the other hand, in the case of no Sn addition, the bulk resistance may be around 5 mΩ · cm or more, and a stable low bulk resistance value of 5 mΩ · cm or less cannot be obtained. In order to maintain, it was confirmed that addition of Sn content of 100 ppm or more was required.

On the other hand, as the Sn content is increased (added in a large amount), a lower bulk resistance value can be obtained. However, when Sn exceeds 2000 ppm, the drop in bulk resistance value becomes gentle, and the bulk resistance value due to the increase of Sn content is obtained. Does not show a significant improvement.

As described above, when Sn is added in excess of 2000 ppm, excessive addition is not preferable because it inhibits the properties of IZO.

In view of the above, in order to lower the bulk resistance value and maintain the properties of the IZO, it is appropriate to make the Sn content in the IZO sintered compact target in the range of 100 to 2000 ppm, which is shown in Tables 1 and 1 and 2. It can confirm from the Example of FIG.

(Evaluation of Film Formation Characteristics)

Next, in the IZO sputtering target of the present invention, the amount of Sn added was changed and film formation was performed to evaluate film characteristics.

As the sputtering target, three kinds of φ 4 inch IZO sputtering targets having different amounts of Sn added in the same manner as described above were used. Sn addition amount, density, and bulk resistance (characteristic value) of this target are as showing in Table 2, respectively.

That is, sample No. In the case of 101, the amount of Sn added was 0 ppm, the density was 6.84 g / cm ³ , and the bulk resistance was 5.22 mΩcm. In the case of 102, the amount of Sn added was 465 ppm, the density was 6.79 g / cm ³ , and the bulk resistance was 2.44 mΩcm. In l03, the amount of Sn added is 2000 ppm, the density is 6.78 g / cm ³ , and the bulk resistance is 1.93 mΩcm.

(Target characteristics) Sample No. Sn addition amount (ppm) Density (g / cm 3) Bulk Resistance (mΩcm) 101 0 6.84 5.22 102 465 6.79 2.44 103 2000 6.78 1.93

Next, the target was attached to a DC magnetron sputtering apparatus using SCG on a substrate, and film formation was performed at room temperature. In sputtering, the pressure was reduced to l.2 × 10 ⁻³ Pa or less in advance, and thereafter, Ar gas (purity 99.99%) and Ar + 1% O ₂ mixed gas (purity 99.99%) were subjected to vacuum pressure of 1.O Pa. Each film was introduced until the film was formed, and a film having a thickness of 150 nm was formed under conditions of a voltage of 360 V and a current of 0.11 A.

Table 3 shows the film properties formed in an Ar gas atmosphere, and Table 4 shows the film properties formed in an Ar + 1% O ₂ mixed gas atmosphere.

(Film characteristics formed in an Ar gas atmosphere) Sample No. Sn addition amount (ppm) X-ray diffraction results Transmittance (%) Resistivity (mΩcm) 101 0 Amorphous 93.0 0.64 l02 465 Amorphous 94.4 0.51 103 2000 Amorphous 94.3 0.59

(Film characteristics formed in an Ar + 1% O ₂ mixed gas atmosphere) Sample No. Sn addition amount (ppm) X-ray diffraction results Transmittance (%) Resistivity (mΩcm) 101 0 Amorphous 96.4 0.59 102 465 Amorphous 94.5 0.60 103 2000 Amorphous 96.8 0.59

As apparent from Table 3, when the film was formed in an Ar gas atmosphere, the transmittances were 93.0%, 94.4%, and 94.3% at 0 (no addition), 465 ppm, and 2000 ppm of Sn added in the IZO target, respectively. It became 0.64 m (ohm) cm, 0.51 m (ohm) cm, 0.59 m (ohm) cm. As described above, no significant change was observed in the film characteristics formed in the Ar gas atmosphere.

In addition, as apparent from Table 4, when the film was formed in an Ar + 1% O ₂ mixed gas atmosphere, the transmittances were 96.4%, 94.5%, at 0 (no addition), 465 ppm, and 2000 ppm of Sn added in the IZO target, respectively. It became 96.8%, and also the specific resistance became 0.59 mΩcm, 0.60 mΩcm, 0.59 mΩcm. In this way, no significant change was observed in the film characteristics formed in the Ar + 1% O ₂ mixed gas atmosphere.

As mentioned above, when 100-2000 ppm of Sn was added, the film | membrane which is the same as Sn-free IZO sputtering target can be obtained, and it was confirmed that addition of Sn00-20000 ppm does not affect the film-forming characteristic. .

As described above, the addition of a small amount of Sn lowers the bulk resistance value of IZO and enables stable film formation without changing the characteristics of the conventional IZO.

The IZO sputtering target for forming a transparent conductive film of the present invention does not essentially lose the characteristics of the (IZO) transparent conductive film mainly composed of oxides of In and Zn, and substantially reduces bulk resistance by adding a very small amount of Sn. Can be effectively lowered. In addition, the target of low bulk resistance can be obtained stably and reproducibly by the manufacturing method of the same target.

Claims (11)

An IZO sputtering target for forming a transparent conductive film mainly composed of In and Zn oxides, which contains 100 to 2000 ppm of Sn. An IZO sputtering target for forming a transparent conductive film mainly composed of In and Zn oxides, which contains 100 to 1000 ppm of Sn. An IZO sputtering target for forming a transparent conductive film containing, as a main component, In and Zn oxides, which contain 100 to 500 ppm of Sn. The bulk resistance is 1-5 m (ohm) * cm, The IZO sputtering target for transparent conductive film formation of any one of Claims 1-3 characterized by the above-mentioned. The IZO sputtering target for forming a transparent conductive film according to any one of claims 1 to 4, wherein the content of unavoidable impurities such as Fe, Al, and Si is less than 10 ppm. The IZO sputtering target for forming a transparent conductive film according to any one of claims 1 to 5, wherein the crystal grain size is 4 µm or less. The IZ0 sputtering target for forming a transparent conductive film according to any one of claims 1 to 6, wherein the crystal grain size is 3 µm or less. The IZO sputtering target for forming a transparent conductive film according to any one of claims 1 to 7, wherein the crystal grain size is 2 µm or less. A powder containing In and Zn as a main component, which contains 100-2000 ppm of Sn and sinters the powder mixed with In ₂ O ₃ and ZnO at 11OO to 15OO ° C so that ZnO is 0.5 to 25% by weight. The manufacturing method of the IZO sputtering target for transparent conductive film formation. 10. The method for producing an IZO sputtering target for forming a transparent conductive film containing In and Zn oxide as a main component, according to claim 9, which contains 100 to l000 ppm of Sn. 10. The method for producing a transparent conductive film-forming IZO sputtering target according to claim 9, which contains 100 to 500 ppm of Sn.