KR100625522B1 - Sputtering target and manufacturing method thereof - Google Patents

Abstract

According to the present invention, in the finishing of the sputtering surface of a target, even if the sputtering surface is flat, even a so-called irregular target having an uneven shape can obtain a processing surface quickly without any smooth processing deformation, and furthermore, in the polishing processing of the sputtering surface A problem caused by the remaining of the abrasive is to provide a sputtering target that is eliminated, and when the sputtering surface of the sputtering target is to be polished, at least one of the constituents of the sputtering target is processed using a powder composed mainly of the sputtering target. The manufacturing method of the sputtering target characterized by the above-mentioned.

Sputtering target, sputter surface, finishing, blasting, shot material, grinding means, suspension,

Description

Sputtering target and its manufacturing method {SPUTTERING TARGET AND MANUFACTURING METHOD THEREOF}

The present invention relates to a sputtering target used for forming a thin film by sputtering and a manufacturing method thereof.

In general, if residual impurities, protrusions, strains, etc., exist on the sputtering surface of the sputtering target due to work polishing, arcing, particles, etc. occur during sputtering, and the ratio of the product to the raw material of the film formation naturally decreases. do. Therefore, as a target used for the sputtering method, the sputtered surface is smoothly processed and washed, and the less residual impurities on the target surface, the less surface roughness, and the less the deformation of the sputtering, the arcing during sputtering The occurrence of particles, etc. is reduced.

ITO and SnO ₂ targets are no exception, and the sputter surface is required to be smoothly processed. As for the processing method of these sputtering targets, the specific technique is disclosed by Unexamined-Japanese-Patent No. 3-257158, Unexamined-Japanese-Patent No. 5-148635, and Unexamined-Japanese-Patent No. 10-298743.

As for the polishing of the sputter surface currently performed, the surface polishing by a planar polishing machine is the mainstream, and in this method, the polishing of the sputter surface is performed using a grindstone. However, this method has a limitation in the polishing accuracy, which causes a problem that inevitably a machining deformation occurs on the sputter surface. Moreover, in this polishing method, it is not possible to carry out polishing processing of a so-called irregular target having an uneven surface formed on the sputter surface. For this reason, surface processing of a heterogeneous target needs to be surface-processed by a process separate from a planar target, and this has a problem that this becomes one of the causes of the rise of a manufacturing cost.

As a grinding | polishing processing method which processing deformation at the time of grinding | polishing is small and is not restrict | limited by the shape of a surface, the process by the blast which sprays a shot material on a to-be-processed surface at high speed and is generally considered is considered. However, in the conventional blasting process, since the shot material as the abrasive is injected at high speed, the phenomenon that the shot material inevitably digs into the surface to be treated occurs. In this way, the shot material captured on the feature surface is difficult to remove by a general cleaning method, and there is a problem that it remains as impurities.

According to the present invention, in the finishing of the sputter surface of a target, even if the sputter surface is flat, even a so-called irregular target having a concave-convex shape can be smoothly obtained without any deformation, and the processing surface can be obtained quickly without further processing, and furthermore, in the sputtering surface, etc. It is an object of the present invention to provide a sputtering target in which a problem caused by residual abrasive is eliminated.

MEANS TO SOLVE THE PROBLEM By using the powder which contains at least 1 or more of the components of a sputtering target as a main component as a material for finishing, this invention smoothly deforms smoothly without problems even if it is a flat sputter | spatter surface, even if it is a so-called shaped target with an uneven shape. The present invention has been completed by seeing that a working surface can be obtained without any problem, and furthermore, a problem caused by the residual of the abrasive used for polishing and the like on the sputter surface can be solved.

That is, the manufacturing method of the sputtering target which concerns on this invention is characterized by processing using the powder which has at least 1 component as a main component among the components of the said sputtering target, when finishing the sputtering surface of a sputtering target. .

One specific aspect includes the step of blasting the said sputter surface using the shot material which consists of a powder which contains at least 1 component as a main component among the components of said sputtering target as a main component.

Moreover, in a preferable aspect in this case, after performing the said blasting process, the sputtering surface of a sputtering target is further included by the grinding | polishing means which disperse | distributes abrasive grains on the surface of an elastic body.

Usually, in order to prevent surface contamination such as digging of the shot material, it is conceivable to employ a shot material (eg, spherical zirconia powder) having a spherical particle shape that is hard to adversely affect the surface. On the basis of detailed surface analysis by the above, it is found that even the use of such spherical powders cannot solve the problems caused by the impurity residues described above.

Moreover, in another specific aspect of this invention, finishing processing is performed using the suspension of the powder which makes at least 1 component of the above components of a sputtering target as a main component.

In such a preferred embodiment, in finishing processing, the finishing processing using the suspension may be carried out first after the blast treatment by the conventional method or the conventional method.

In the case of a planar target or the like, since the surface impurities are removed after the conventional polishing, the finishing processing can be performed using the suspension described above.

(The best form for carrying out the invention)

The manufacturing method of the sputtering target of this invention which concerns on a 1st aspect uses the short material which consists of a powder which contains at least 1 component as a main component among the components of the said sputtering target, when finishing the sputtering surface of a sputtering target. And blasting the sputter surface.

The sputtering target made into the object of this invention is not specifically limited about the kind, It is applied to the various sputtering targets known conventionally, and are obtained.

Specifically, ITO (In ₂ O ₃ -SnO ₂ ) type, Al type, Al-Si type, Al-Ti type, Al-Cu type, which are used to form a transparent conductive film or an electrode film of a display device such as a liquid crystal display Used for the formation of recording films or protective films of recording media such as Ti, Mo, Mo-Ta, Ta, W, Cr, etc., sputtering, magneto-optical recording media, phase change recording media, etc. Co-Cr-Pt-based, Co-Cr-Ta-based, Co-Ni-Cr-based, C-SiTb-Fe-Co-based, Si-based, Ge-Sb-Te-based, Ag-In-Sb-Te-based, Fe-Ta, Fe-Al-Si, Fe-Zr, Ni-Fe, Co-Zr, which are used for thin film formation of recording devices such as targets such as ZnS-SiO ₂ systems, magnetic heads, thermal print heads, etc. Targets such as -Nb-based, Fe-N-based, Ta-SiO ₂ -based, Ta ₂ O ₅ -based, SiAlON-based, Si ₃ N ₄ -based, Al-Si based, MoSi ₂ based, WSi _It can be applied to targets such as _{2 type} and Ti type.

As an example, the case where the target for ITO film formation is manufactured is demonstrated. The ITO target can be produced by any method of cold press and hot press, and is obtained by press molding and sintering a powder mixture composed mainly of indium oxide and tin oxide in either method.

Specifically, in the cold press method, the indium oxide powder and the tin oxide powder are weighed and mixed, and a binder is further added to press molding and degreased, followed by sintering to obtain a target sintered body. The obtained sintered compact is further processed, ground and finished to be molded into a target having a predetermined shape and a predetermined dimension. On the other hand, in the hot press method, the indium oxide powder and the tin oxide powder are weighed and mixed, mixed with a dry ball mill, and then hot pressed to form, and further processed, ground, and finished to give a predetermined shape and a predetermined dimension. It is molded into a target.

In the present invention, in the finishing processing after target molding, the sputter surface is blasted with a specific shot material. In the present invention, a method conventionally performed can be suitably employed for the blasting method itself. In general, the blasting treatment is performed by spraying a shot material made of a powder material having a polishing action together with a gas such as pressurized air or a liquid such as water to the surface of the object to be treated, so that foreign matter or protrusions adhered to the surface of the object to be treated. It means the surface processing method to remove the.

The blast treatment apparatus used for the blast treatment in the present invention is not particularly limited, either, and can be suitably used in accordance with the size of the target for which the apparatus available in the conventional market is the object of treatment. In other words, the present invention is not particularly limited except for using the short material as a specific material described later. For example, an existing blasting apparatus may be useful as it is, and even in that no special equipment is required. It is advantageous.

In the present invention, first, a blast treatment is used for finishing the target surface, and a short material made of a specific powder is blown to polish the surface. Therefore, even in the case of a heterogeneous target having an uneven surface on the sputter surface, there is no problem. It is advantageous in that it can be processed quickly.

Moreover, in the method of this invention, since the powder which contains at least 1 or more of the components of the said sputtering target as a main component is used as a component of a shot material at the finishing of a target surface, after a blasting process, it wash | cleans Even if the shot material remains on the sputter surface of the target later, since the main component of the shot material becomes a constituent of the target, occurrence of adverse effects due to the remaining of the shot material can be substantially prevented.

As a result of preventing the adverse effects resulting from such impurity residues, the shot material is particularly preferably a powder composed of any one of the target components. In this case, even if the shot material remains unavoidably, this does not constitute an impurity. More preferably, the shot material is made of powder of the same component as the target. In this case, the shot material may not only be impurity even if the shot material remains, and the compositional stain due to the remaining shot material may be completely prevented.

For example, in a case of producing a sputtering target for ITO, as a component of a preferred short, In ₂ O ₃ system powder, SnO ₂ based powder, In ₂ O ₃ -SnO ₂ based powder, In ₂ O ₃ -SnO ₂ (ITO) may be a powder, and target such as _{in 2 O 3 -SnO 2 (ITO} ) powder having the same composition.

In addition to the components of the sputtering target, the component added to the shot material for improving the properties of the shot material is not particularly limited as long as it is possible to industrially produce a shot suitable for the blast treatment efficiently. For example, SnO _2, if short words Fecal material comprising, as an additional element, may be added to the iron oxide, cobalt oxide, nickel oxide and the like.

In addition to the components of the sputtering target, the addition amount of the component added to the shot material is also related to the purity of the desired target, preferably 1% by weight or less, more preferably 0.5% by weight or less, and the smaller the amount good.

The powder used for the shot material is more fragile than the constituent material of the sputtering target, and it is particularly preferable that the shot material breaks when the shot material collides with the target. This is because the side of the shot material is more fragile than the target, so that undesired scars do not appear on the target. Although the particle size of the powder used for a shot material may be larger than 1 mm, when the particle size of a shot material is too large, since it will become difficult to spray a shot material in a favorable state at the time of blasting, a particle size of 1 mm or less is preferable. In addition, if the properties of the powder as described above, the shot material itself is broken during collision, there is an advantage that the processing deformation is not large to absorb the impact to some extent.

By using such a material as a short material, the surface roughness (Ra) can be made into the processing surface of 5.0 micrometers or less, and also the sputtering target with few processing distortions can be obtained irrespective of the shape.

More preferably, when a shot material having a particle size of 710 µm or less is used, a machined surface having a surface roughness Ra of 2.5 or less can be obtained. Further, when the powder used for the shot material is smaller, the surface roughness is smaller, the smoother processing can be performed, and the processing deformation is also smaller. However, if the surface roughness (Ra) is to be 0.2 μm or less, a short material having an average particle diameter of 45 μm or less should be used. It is generally difficult and efficient to grind the average particle diameter of the short material powder to 45 μm or less effectively. not.

In addition, when the shot material is of the same hardness and strength as the target, or when the target is easily broken, the powder of the shot is adjusted to a particle diameter of 500 µm or less, the blast pressure is lowered, or the injection nozzle and the target of the blasting apparatus. By increasing the distance, it is possible to prevent the occurrence of processing deformation due to excessive impact. In normal blasting conditions, the blast pressure is 3 to 5 kg / cm 2, and the distance between the nozzle and the target is about 10 to 30 cm.

Furthermore, in the method according to the present invention, after the blasting treatment as described above, if necessary, the sputtering surface of the sputtering target is again polished by polishing means by dispersing the abrasive grains on the surface of the elastic body. It is desirable to.

Thus, by polishing by grinding means in which whetstone particles are dispersed on the surface of the elastic body, for example, a surface roughness of about 0.2 to 5.0 µm can be efficiently polished to a range of 0.2 µm ≤ Ra <1.5 µm. In addition, in the method of polishing by polishing means in which whetstone particles are dispersed on the surface of such an elastic body, even in the case of a heterogeneous target in which the uneven surface is formed on the sputter surface because the polishing means itself has elasticity, there is no problem. It can be polished.

In the above description, the upper limit of the surface roughness is set to 1.5 µm by the use of such a method because the processing over the surface roughness of 1.5 µm is sufficient for the blasting treatment. On the other hand, if the surface roughness is less than 0.2 µm, the working time It's long and not practical. The elastic body is not particularly limited as long as the object deforms in a pressure at which the target is not deformed or split, and urethane, foamed urethane, sponge, and the like can be used. Moreover, it is preferable to avoid the material disperse | distributed to this elastic body and the substance which reacts with a target material. The average particle diameter of the particles to be dispersed also depends on the material of the particles. For example, in the case of using alumina, an average particle diameter of about 7 to 250 µm is preferable in terms of work efficiency. In addition, the particle size can be selected in consideration of particle size standards of abrasives such as JIS-R600.

The method according to the present invention described above is particularly useful for metal-based targets and oxide-based targets having a small viscosity that does not penetrate the target surface of the shot material of the blast.

In the method of this invention which concerns on a 2nd aspect, it can refine | finish using the suspension containing the powder which has at least 1 component as a main component among the components of a sputtering target as mentioned above. In this aspect, the finishing process may be carried out using the above-mentioned suspension after the blasting process according to the conventional method or the conventional method in the finishing process.

As the powder used in this case, the above-mentioned materials can be used in the same manner. The particle size of the powder may be selected according to the optimum material range depending on the material to be polished, can be determined with reference to the particle size of the abrasive, such as JIS-R6001.

In the case of adjusting the particle size of the powder, preferably, commercially available powder raw materials are temporarily quenched once, and the grain growth or agglomeration (assembly) is carried out, for example, by Desired particle size powder can be obtained. The preferable average particle size range as a secondary particle is 20-250 micrometers, More preferably, it is 50-150 micrometers.

In order to prepare a suspension, this powder is mixed with pure water to make a suspension. In this case, the weight ratio of powder: pure water is 50: 50-90: 10, More preferably, it is 60: 40-85: 15.

In addition, the used suspension can be reused by carrying out a treatment such as removing coarse particles with a suitable mesh sieve, which is advantageous in terms of reducing manufacturing cost and saving resources. However, as the frequency of use increases, it is conceivable that the amount of impurities in the suspension increases. Therefore, it is preferable to monitor the amount of impurities in the suspension when reused.

Finishing processing using the above suspension can be carried out by, for example, applying the suspension to the polishing target area and rubbing with an elastic or flexible material such as a sponge.

(Example)

Although the Example and the comparative example of this invention are shown below, this invention is not limited to the aspect of the following Example.

(Comparative Example 1)

Using four kinds of commercially available alanthanum, glass, Fe, and zirconia as a blasting shot material, the ITO sputtering target of the plate is finished, and the sputter surface is cleaned by ultrasonic waves. As a result, the surface roughness Ra of the sputter surface was 1.8, 3.3, 4.3 and 1.5 µm, respectively. In addition, 2800 ppm of Al, 5000 ppm of Si, 2000 ppm of Fe, and 1800 ppm of Zr were detected for the impurity of a sputtering surface, respectively, and it was not a product sufficient as an ITO sputtering target.

(Comparative Example 2)

The finishing process was performed by a planar polishing machine, and sputtering was performed using the ITO sputtering target of the flat plate which wash | cleaned the sputter surface by the ultrasonic wave. As a result, the initial arcing sputter occurred 506 times, and many particles were confirmed on the target.

Example 1

2000 ppm dry mixed CoO to SnO ₂ having an average particle diameter of 0.8 to 4.0 µm was put in a commercial A1 ₂ 0 ₃ development as it was, and heat-treated at 1500 ° C. for 3 hours to coagulate. The agglomerated CoO containing 2000 ppm of SnO ₂ powder is pulverized until it passes through a sieve having a graduation of 710 µm, and a shot of SnO ₂ powder containing 2000 ppm of CoO having a particle diameter of 710 µm or less is obtained. When the thus-obtained shot material and the ITO sputtering target for finishing processing were rubbed, it was found that the side of the shot material was broken first, and the side of the shot material was easily broken.

The SnO ₂ powder containing 2000 ppm of CoO thus obtained is used to finish the ITO sputtering target of the plate by blasting, and the sputtered surface is cleaned by ultrasonic waves.

As a result, the surface roughness Ra of the sputtered surface was 1.0 µm, and impurities of the sputtered surface were not detected, and Co was similarly detected. Sputtering was performed using this ITO sputtering target. As a result, it was confirmed that the initial arcing of the sputter was 276 times, and the particles on the target were reduced than in Comparative Example 2.

Example 2

By using blasting using SnO ₂ powder containing 2000 ppm of CoO obtained in the same manner as in Example 1, the irregular ITO sputtering target having irregularities on the sputter surface was polished, and the sputter surface was cleaned by ultrasonic waves.

As a result, the surface roughness of the sputter surface was 1.0 µm, and impurities of the sputter surface were not detected, and Co was not detected in the same way. Sputtering was performed using this irregular ITO sputtering target with irregularities. As a result, it was confirmed that the initial arcing of the sputter was 290 times, and the particles on the target were smaller than in Comparative Example 2.

Example 3

Finishing of the ITO sputtering target of the plate was carried out by blasting using SnO ₂ powder containing 2000 ppm of CoO obtained in the same manner as in Example 1, and further, alumina abrasive grains having an average powder diameter of 50 µm were placed on the urethane surface. The article was dispersed, polished, and the sputtered surface was cleaned by ultrasonic waves.

As a result, the surface roughness Ra of the sputter surface was 0.5 µm, and impurities of the sputter surface were not detected, and Co and Al were not detected in the same way.

Sputtering was performed using the ITO sputtering target of this flat plate. As a result, as compared with Example 1, it was confirmed that the arcing of the sputtering initial stage was 38 times, and the particles also decreased.

Example 4

By blasting using SnO ₂ powder containing 2000 ppm of CoO obtained in the same manner as in Example 1, the irregular sputtering target having irregularities on the sputter surface was polished, and the average powder particle size was further increased on the urethane surface. Polishing was carried out by means of a polishing member in which 50-µm alumina grindstone particles were dispersed, and the sputter surface was cleaned by ultrasonic waves.

As a result, the surface roughness Ra of the sputtered surface was 0.5 µm, and impurities of the sputtered surface were not detected, but became 100 ppm or less together with Co and Al.

Sputtering was performed using a heterogeneous ITO sputtering target having irregularities on the sputter surface. As a result, in comparison with Example 2, it was confirmed that the arcing of the sputter initial stage was 67 times, and the particles also decreased.

Example 5

A commercially available SnO 2 powder having an average particle diameter of 0.4 μm was temporarily quenched at a temperature of 1500 ° C., and was grained (assembled) to a particle size of 500 μm or less.

Next, in processing the surface of the irregular ITO sputtering target of the irregularities on the sputter surface, the sputter surface having the irregularities was first 0.3 mm roughly cut using a general blasting method. Blast conditions at this time are as follows.

Projectile: Alandom

Particle diameter range: 74 ~ 44㎛

Projection pressure: 4kgf / ㎠

Subsequently, the SnO ₂ powder with pure water prepared by the above method 85: and applied to the sputter surface and the suspension mixed in a ratio (by weight) of 1, from the top was subjected to grinding by a sponge rubbing. In this case, the SnO ₂ powder so easy being broken than the ITO sputtering target the subject side of the polishing slurry was agglomerated by the above method, without damaging the surface of the ITO sputtering target was carried out for effective finish polishing by fine granulation. After the finishing polishing, ultrasonic cleaning was performed and dried. The surface roughness Ra of the obtained sputter surface was 0.6 micrometer, and the impurity was not detected from the sputter surface by the shot material used by the blast process.

Sputtering was performed using the obtained sputtering target. As a result, it was confirmed that the initial arcing of the sputter was 50 times as compared with Example 4, and the particles were also reduced.

As is clear from the results of the above examples, in the method for producing a sputtering target according to the present invention, the sputtering surface is to be finished by using a powder composed of at least one component among the components of the sputtering target. , An excellent effect can be solved in that the problem caused by remaining of the finishing material and the like as impurities can be solved.

In addition, in the case where the above powder is used as the shot material of the blasting treatment, despite the shape of the sputtering surface, even a so-called irregular target having a concave-convex shape even in a flat surface can be quickly obtained without processing deformation smoothly without any problems. Furthermore, it is excellent in the point which can solve the problem caused by remaining a blast shot material etc. as an impurity on a sputter surface.

Claims (10)

delete delete delete delete delete delete delete In the manufacturing method of the sputtering target which processes using the powder which consists of at least 1 component as a main component among the components of the said sputtering target, when finishing the sputtering surface of a sputtering target, A method for producing a sputtering target, characterized in that the finishing processing is carried out using a suspension of a powder composed mainly of at least one of the components of the sputtering target. The method for producing a sputtering target according to claim 8, wherein a finishing process using the suspension is performed after blasting. It was obtained by the method of Claim 8, The sputtering target characterized by the above-mentioned.