JPWO2008139906A1 - Sputtering target and manufacturing method thereof - Google Patents

Abstract

Provided are a sputtering target, a manufacturing method thereof, and a sputtering method, which can significantly improve initial stability, reduce arcing in the middle and later stages of sputtering, and can be manufactured at low cost. A deposit is deposited on the non-erosion portion by sputtering, and the deposit has a good crystallinity at least up to a layer near the interface. Further, the deposit on the non-erosion part after being subjected to sputtering and energy of 50 Wh / cm 2 or more is deposited with substantially no void between the sputtering surface, Moreover, it has a water adsorption layer on the sputtering surface of the target.

Description

  The present invention relates to a sputtering target and a manufacturing method thereof.

  In general, a sputtering method is known as one of methods for forming a thin film. The sputtering method is a method of obtaining a thin film by sputtering a sputtering target, is easy to increase in area, and can be efficiently formed into a high-performance film, and is used industrially. In recent years, as sputtering methods, there are known a reactive sputtering method in which sputtering is performed in a reactive gas, and a magnetron sputtering method in which a magnet is placed on the back surface of a target to increase the speed of thin film formation.

Among the thin films used in such a sputtering method, in particular, an indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ composite oxide, hereinafter referred to as “ITO”) film has high visible light transmittance, and Because of its high conductivity, it is widely used as a transparent conductive film for liquid crystal display devices, heat generation films for preventing condensation of glass, infrared reflective films, and the like.

  For this reason, in order to form a film more efficiently and at a lower cost, improvement of sputtering conditions and a sputtering apparatus are carried out every day, and it is important how to operate the apparatus efficiently.

  In such ITO sputtering, the time from when a new sputtering target is set until the initial arc (abnormal discharge) disappears and the product can be manufactured is short, and how long it can be used after being set (integrated) Sputtering time: target life) is a problem.

  Conventionally, it is said that the initial arc of a sputtering target is reduced as the target surface is polished and smoothed, and a surface polished target having a smooth surface has become the mainstream.

  Further, it is said that when sputtering is continuously performed, black deposits called nodules are generated on the target surface, which causes abnormal discharge or a source of particles. Therefore, in order to prevent thin film defects, periodic nodule removal is required, leading to a problem that productivity is reduced.

  For example, a technique for preventing the occurrence of arcing and nodules by setting the surface roughness of the target within a predetermined range has been developed (see Patent Documents 1 and 2). However, in order to produce an ITO sputtering target having such a predetermined surface roughness, after sintering, the thickness is adjusted by grinding, and then gradually 3 to 4 polishing steps using a fine polishing wheel There is a problem that manufacturing time and cost increase.

  In addition, a technique for preventing generation of nodules and abnormal discharge by cleaning the grinding powder by ultrasonic cleaning of the sputtering target or rubbing and peeling off the adhesive tape (see Patent Document 3). ). However, this technique has a problem that the grinding powder cannot be sufficiently removed.

  Furthermore, for example, even if grinding powder or the like is removed by ultrasonic cleaning or the like, dust or the like adheres to the target surface in a subsequent process of bonding the target onto the backing plate, and the initial arc and particle suppression effect is reduced. is there. In addition, if ultrasonic cleaning is performed immediately before the packaging process, which is the final process of the sputtering target, it is possible to simultaneously remove grinding powder and dust attached by bonding, etc. There is a problem that ultrasonic cleaning after bonding is very difficult.

  On the other hand, by making all or part of the target surface except the bonding surface rough, the target particles that did not adhere to the thin film formation substrate during continuous sputtering are trapped as adhering substances. There is a technique that suppresses particles generated during the period of time and reduces the number of cleanings (see Patent Document 4). However, when this concept is incorporated into the above-described technique, it is necessary to make only the non-erosion portion rough after the smoothing process, and there is a problem that the process becomes extremely complicated.

  In addition, we developed a technology that significantly reduces the initial arc by removing burrs, grinding powder, dust and dirt generated during processing by applying surface treatment using a laser beam having a predetermined pulse width (Patent Document 5, 6).

  However, according to the surface treatment with the laser beam, the initial arc can be almost completely removed. However, since the treatment with the laser beam is performed, there is a disadvantage that the equipment investment is increased.

  Furthermore, the technique which surface-treats by injecting water with a predetermined pressure after surface grinding was developed (refer patent document 7).

  This technology is mainly to reduce microcracks on the target surface, but it cannot reduce particles caused by deposits deposited on non-erosion parts, and cleaning must be performed as usual. There's a problem.

  In addition, from the technical common sense that the presence of water is strictly prohibited in a vacuum apparatus such as a sputtering apparatus, in the prior art, after washing with water or spraying water, vacuum heating drying or heat treatment is used. A drying step was essential.

Japanese Patent No. 2750483 Japanese Patent No. 3152108 JP 11-117062 A Japanese Patent Laid-Open No. 4-301074 JP 2003-55762 A Japanese Patent Laid-Open No. 2003-73821 JP-A-2005-42169

  Therefore, in view of such circumstances, the present invention has an object to provide a sputtering target that can significantly improve initial stability and at the same time reduce arcing in the middle and later stages of sputtering, and can be produced at low cost, and a method for producing the same. To do.

  When the sputtering target in which the deposit on the non-erosion portion of the target surface is deposited without substantially any gap between the sputtering surface and the sputtering surface is formed, the scattering of the deposit is reduced and the cleaning is performed. The inventors have found that the number of times can be reduced, and as a result, the target life can be improved and the manufacturing cost of the film can be reduced, and the present invention has been completed.

  In addition, when such a sputtering target is present as a water adsorbing layer to the extent that water, which has been strictly prohibited in the past, cannot be visually confirmed, the deposit on the non-erosion portion can be stabilized without affecting the sputtering. In the middle and later stages of sputtering, the scattering of deposits is reduced, the number of cleanings can be reduced, and as a result, the target life can be improved and the manufacturing cost of the film can be reduced. Completed.

  The first aspect of the present invention is characterized in that a deposit is deposited on a non-erosion part by being subjected to sputtering, and the deposit has a good crystallinity at least up to a layer near the interface. It is in the sputtering target.

In the first aspect, since the deposited layer on the non-erosion part is deposited with good crystallinity from the surface to the vicinity of the interface of the target, the deposit is stably deposited and the thermal expansion coefficient over the whole. Is a sputtering target that is uniform and has no fear of peeling, resulting in a long target life.
According to a second aspect of the present invention, in the sputtering target according to the first aspect, the layer in the vicinity of the interface is a region from the interface to near 100 nm, and the region is a crystal layer having good crystallinity. The sputtering target is characterized.

  In the second aspect, since the layer in the vicinity of the interface from the interface of the deposited layer to about 100 nm is a crystal layer, the sputtering target is free from the possibility of peeling or the like.

According to the third aspect of the present invention, the deposit on the non-erosion portion after being subjected to sputtering and charged with energy of 50 Wh / cm ² or more has substantially no void between the sputter surface. The sputtering target is characterized by being deposited.

  In the third aspect, a sputtering target in which a deposit on a non-erosion part is stably formed after being subjected to sputtering for a predetermined period or more, there is no gap between the sputtering surface and there is no possibility of peeling or the like. Yes, and as a result, it has a long target life.

  According to a fourth aspect of the present invention, there is provided the sputtering target according to the third aspect, wherein a gap between the deposit and the sputtering surface is 1 μm or less.

  In the fourth aspect, the deposit on the non-erosion portion is stably formed, and there is substantially no gap of 1 μm or less between the sputtering surface and there is no possibility of peeling.

  According to a fifth aspect of the present invention, there is provided a sputtering target having a water adsorption layer on the sputtering surface of the target.

  In the fifth aspect, the water adsorbing layer present on the sputter surface stably deposits deposits on the non-erosion part, and is difficult to peel off and scatter, thereby improving the target life.

  According to a sixth aspect of the present invention, there is provided the sputtering target according to the fifth aspect, wherein the water adsorption layer is present at least in a non-erosion portion of the sputtering surface.

  In the sixth aspect, since the deposit is deposited on the water adsorption layer existing in the non-erosion portion, the deposit is deposited in a state in which separation from the surface hardly occurs.

  According to a seventh aspect of the present invention, in the sputtering target according to the fifth or sixth aspect, the water adsorbing layer is formed by wetting the sputter surface with water and then blowing off excessively adhering water with an air blow. The sputtering target is characterized by the above.

  In the seventh aspect, the water adsorption layer can be formed by wetting the sputter surface with water and then blowing off excess water by air blow.

  According to an eighth aspect of the present invention, in the sputtering target according to the fifth or sixth aspect, the water adsorption layer is formed by contacting a water absorbing member that has absorbed water. In the sputtering target.

  In the eighth aspect, the water adsorbing layer can be formed by bringing the water absorbing member that has absorbed water into contact with the water absorbing member so as not to attach excessive water.

  According to a ninth aspect of the present invention, in the sputtering target according to any one of the fifth to eighth aspects, the water adsorbing layer contains water to an extent that cannot be visually observed. In the sputtering target.

  In the ninth aspect, a water adsorbing layer is formed by water adhering to such an extent that water cannot be observed visually.

  A tenth aspect of the present invention is the sputtering target according to any one of the fifth to ninth aspects, wherein the sputtering surface having the water adsorption layer irradiates light having a wavelength having a photon energy of 6.6 eV. The sputtering target is characterized in that the photoelectron yield is 400 count / sec or less.

  In the tenth aspect, the presence of the water adsorption layer absorbs photons generated when photoelectric analysis is performed and photoelectrons are irradiated, and the photon absorptance is reduced.

  An eleventh aspect of the present invention is the sputtering target according to any one of the fifth to tenth aspects, wherein the water adsorption layer is formed and then packed and shipped. In the target.

  In the eleventh aspect, the effect of the water adsorbing layer is manifested during sputtering even when the date and time has elapsed since the water adsorbing layer was formed and then packed and shipped.

  A twelfth aspect of the present invention is the sputtering target according to any one of the fifth to tenth aspects, wherein the water adsorption layer is formed immediately before the start of sputtering discharge. In the target.

  In the twelfth aspect, if the water adsorption layer is formed immediately before the start of sputtering discharge, the effect is manifested during sputtering.

  According to a thirteenth aspect of the present invention, the sputtering target according to any one of the fifth to twelfth aspects is subjected to sputtering and deposits are deposited on the non-erosion portion, and the deposits are at least in the vicinity of the interface. The sputtering target is characterized in that the crystallinity is well deposited up to this layer.

  In the thirteenth aspect, the deposited layer on the non-erosion part is deposited with good crystallinity from the surface to the vicinity of the interface of the target, so that the deposit is stably deposited and the coefficient of thermal expansion over the whole. Is a sputtering target that is uniform and has no fear of peeling, resulting in a long target life.

  According to a fourteenth aspect of the present invention, in the sputtering target according to the thirteenth aspect, the layer in the vicinity of the interface is a region from the interface to near 100 nm, and the region is a crystal layer having good crystallinity. The sputtering target is characterized.

  In the fourteenth aspect, since the layer in the vicinity of the interface from the interface of the deposited layer to about 100 nm is a crystal layer, the sputtering target is free from the possibility of peeling or the like.

A fifteenth aspect of the present invention is the one after the sputtering target according to any one of the fifth to twelfth aspects is subjected to sputtering and energy of 50 Wh / cm ² or more is input, to the non-erosion part In the sputtering target, the deposit is deposited with substantially no gap between the deposited surface and the sputtering surface.

  In the fifteenth aspect, even when the sputtering is performed for a predetermined period or longer, the deposit on the non-erosion portion is stably formed, there is no gap between the sputtering surface, and there is no possibility of peeling.

  A sixteenth aspect of the present invention is the sputtering target according to the fifteenth aspect, wherein a gap between the deposit and the sputtering surface is 1 μm or less.

  In the sixteenth aspect, the deposit on the non-erosion portion is stably formed, and there is substantially no gap of 1 μm or less between the sputtering surface and there is no possibility of peeling.

  According to a seventeenth aspect of the present invention, there is provided a sputtering target manufacturing method comprising the step of forming a water adsorption layer on the sputtering surface of the target.

  In the seventeenth aspect, a sputtering target with an improved target life can be manufactured by forming a water adsorption layer on the sputtering surface of the target.

  According to an eighteenth aspect of the present invention, in the sputtering target manufacturing method according to the seventeenth aspect, the water adsorption layer is formed on at least a non-erosion portion of the sputtering surface. is there.

  In the eighteenth aspect, a sputtering target having an improved target life can be obtained by forming a water adsorption layer at least in the non-erosion portion.

    According to a nineteenth aspect of the present invention, in the method for manufacturing a sputtering target according to the seventeenth or eighteenth aspect, the water adsorbing layer is wetted on the sputtered surface of the target with water, and then excessively attached moisture is blown by air. It is in the manufacturing method of the sputtering target characterized by forming by blowing away.

  In the nineteenth aspect, the water adsorbing layer can be formed relatively easily by wetting the sputter surface of the target with water and then blowing off excessively adhering water with air blow.

  According to a twentieth aspect of the present invention, in the method for producing a sputtering target according to the nineteenth aspect, the step of wetting with water includes pouring water, immersing in water, spraying water, absorbing water. It is in the manufacturing method of the sputtering target characterized by performing either by making a member contact.

  In the twentieth aspect, the sputtering surface of the target can be wetted with water by various methods such as pouring water, immersing in water, spraying water, or contacting a water absorbing member that has absorbed water.

  According to a twenty-first aspect of the present invention, in the sputtering target manufacturing method according to the seventeenth or eighteenth aspect, the water adsorption layer is formed by contacting a water absorbing member that has absorbed water. It is in the manufacturing method.

  In the twenty-first aspect, the water adsorbing layer can be formed by bringing the water absorbing member that has absorbed water into contact with the water absorbing member so as not to attach excessive water.

  According to a twenty-second aspect of the present invention, in the method for producing a sputtering target according to any one of the seventeenth to twenty-first aspects, the water adsorption layer is such that water is present to an extent that cannot be visually observed. It is in the manufacturing method of the sputtering target characterized.

  In the twenty-second aspect, the water adsorbing layer can be formed by adhering moisture so that water is present to such an extent that it cannot be visually observed.

  According to a twenty-third aspect of the present invention, in the sputtering target manufacturing method according to any one of the seventeenth to twenty-second aspects, the surface having the water adsorbing layer emits light having a wavelength having a photon energy of 6.6 eV. The method for producing a sputtering target is characterized in that the photoelectron yield upon irradiation is 400 count / sec or less.

  In the twenty-third aspect, the presence of the water-adsorbing layer absorbs photons generated when photoelectric analysis is performed and irradiates photoelectrons, thereby reducing the photoelectron yield.

  According to a twenty-fourth aspect of the present invention, in the method for manufacturing a sputtering target according to any one of the seventeenth to twenty-third aspects, after the target body is joined to a backing plate, the step of forming the water adsorption layer is performed. Then, it is in the manufacturing method of the sputtering target characterized by packing.

  In the twenty-fourth aspect, a sputtering target having a water adsorption layer can be formed relatively easily by forming the water adsorption layer before packaging after the target body is joined to the backing plate.

    Based on the technical idea of the present invention described above, it is possible to realize a sputtering method characterized by starting sputtering in a state where a water adsorption layer is present on the sputtering surface of the target and continuing the sputtering.

  In such a sputtering method, the water adsorbing layer present on the sputtering surface stably deposits deposits on the non-erosion portion, and is difficult to peel off and scatter, thereby improving the target life.

  In such a sputtering method, it is preferable to start sputtering in a state where the water adsorption layer is present at least in a non-erosion portion of the sputtering surface.

  According to this, since the deposit is deposited on the water adsorption layer existing in the non-erosion portion, it is deposited in a state in which separation from the surface hardly occurs.

  In the sputtering method described above, it is preferable to form the water adsorption layer immediately before the start of sputtering discharge.

  According to this, the target life can be improved by forming the water adsorption layer immediately before the start of sputtering discharge.

  In the sputtering method described above, it is preferable that the water adsorption layer is formed by wetting the sputtering surface of the target with water and then blowing off excessively attached water with an air blow.

  According to this, after wetting the sputtering surface with water, the water adsorbing layer can be formed by blowing off excess water by air blow.

  Further, in the sputtering method described above, wetting the target with the water before mounting the target on the sputtering apparatus, pouring water, immersing in water, spraying water, contacting a water absorbing member that has absorbed water It is preferable to do either.

  According to this, the sputter surface of the target can be wetted with water by various methods such as pouring water, immersing in water, spraying water, or contacting a water absorbing member that has absorbed water.

  In the sputtering method described above, it is preferable that the water adsorption layer is formed by bringing a water absorbing member that has absorbed water into contact therewith.

  According to this, a water adsorbing layer can be formed if the water absorbing member that has absorbed water is brought into contact with the water absorbing member so as not to attach excessive water.

  Moreover, in the sputtering method described above, it is preferable that the water adsorbing layer contains water to the extent that it cannot be visually observed.

  According to this, the water adsorbing layer can be formed by attaching water so that water is present to such an extent that it cannot be visually observed.

  In the sputtering method described above, it is preferable that the surface having the water adsorption layer has a photoelectron yield of 400 count / sec or less when irradiated with light having a wavelength having a photon energy of 6.6 eV.

  According to this, due to the presence of the water adsorption layer, photons generated when photoelectric analysis is performed and photoelectrons are irradiated are absorbed, and the photon absorptance is reduced.

  Further, in the above-described sputtering method, it is preferable that the deposit deposited on the non-erosion part by sputtering has a good crystallinity at least up to a layer near the interface.

  According to this, since the deposited layer on the non-erosion part is deposited with good crystallinity from the surface to the vicinity of the target interface, the deposit is stably deposited and the thermal expansion coefficient becomes uniform throughout. There is no risk of peeling and the like, resulting in a sputtering method with a long target life.

  In the sputtering method described above, the layer in the vicinity of the interface is preferably a region from the interface to near 100 nm, and the region is preferably a crystal layer with good crystallinity.

  According to this, since the layer in the vicinity of the interface from the interface of the deposited layer to about 100 nm becomes a crystal layer, the sputtering method is free from the possibility of peeling or the like.

Further, in the sputtering method described above, there is substantially no void between the deposit on the non-erosion part after the energy of 50 Wh / cm ² or more has been input since the start of sputtering and the target surface. It is preferable to deposit.

  According to this, even if it is subjected to sputtering for a predetermined period or longer, the deposit on the non-erosion part is stably formed, there is no gap between the sputtering surface, and there is no possibility of peeling or the like.

  In the sputtering method described above, the gap between the deposit and the target surface is preferably 1 μm or less.

  According to this, the deposit on the non-erosion portion is stably formed, and there is substantially no gap of 1 μm or less between the sputtering surface and there is no possibility of peeling.

  In the present invention, by providing a water adsorption layer on the sputtering surface of the sputtering target, deposits on the non-erosion part during sputtering are deposited with good crystallinity from the beginning, and there are substantially no gaps between the sputtering surface and the sputtering surface. Therefore, the initial stability is significantly improved and particles in the middle and late stages of sputtering are reduced, and the scattering of deposits is reduced in the middle and late stages of sputtering to reduce the number of cleanings. As a result, the target life can be improved.

4 is a graph showing the relationship between the cumulative input amount of Test Example 1 and the number of arcing operations. It is a photograph which shows the external appearance of the target surface after 50 Wh / cm < ² > injection | throwing-in of Example 1. FIG. It is a photograph which shows the external appearance of the target surface after 50 Wh / cm < ² > injection | throwing-in of the comparative example 1. FIG. ² is a photograph showing the appearance of the target surface after charging 75 Wh / cm ^{2 in} Example 1. FIG. It is a photograph which shows the external appearance of the target surface after 75 Wh / cm < ² > injection | throwing-in of the comparative example 1. FIG. ² is a cross-sectional SEM photograph of a non-erosion part after introduction of 50 Wh / cm ^{2 in} Example 1. It is a cross-sectional SEM photograph of the non-erosion part after 50 Wh / cm < ² > injection | throwing-in of the comparative example 1. ² is a cross-sectional SEM photograph of a non-erosion part after charging 75 Wh / cm ^{2 in} Example 1. It is a cross-sectional SEM photograph of the non-erosion part after 75 Wh / cm < ² > injection | throwing-in of the comparative example 1. FIG. It is a graph which shows the atmospheric photoelectron spectroscopy analysis result of Example 2 and Comparative Example 3. 6 is a cross-sectional TEM photograph of the vicinity of an interface between a target surface and a deposit in Example 1 of Test Example 3. 12 is an electron diffraction image of a portion * 1 in FIG. 12 is an electron diffraction image of a portion * 2 in FIG. 11. It is an electron diffraction image of the part of * 3 of FIG. FIG. 12 is an electron diffraction image of a portion * 4 in FIG. 11. 12 is an electron diffraction image of a portion indicated by * 5 in FIG. 11. 6 is a cross-sectional TEM photograph in the vicinity of an interface between a target surface and a deposit in Comparative Example 1 of Test Example 3. It is an electron diffraction image of the part of * 1 of FIG. It is an electron diffraction image of the part of * 2 of FIG. It is an electron diffraction image of the part of * 3 of FIG. It is an electron diffraction image of the part of * 4 of FIG. It is an electron diffraction image of the part of * 5 of FIG. 10 is a cross-sectional TEM photograph of the vicinity of an interface between a target surface and a deposit in Example 3 of Test Example 4; It is an electron diffraction image of the part of * 1 of FIG. It is an electron diffraction image of the part of * 2 of FIG. It is an electron diffraction image of the part of * 3 of FIG. It is an electron diffraction image of the part of * 4 of FIG. It is an electron diffraction image of the part of * 5 of FIG. 6 is a cross-sectional TEM photograph in the vicinity of an interface between a target surface and a deposit in Comparative Example 5 of Test Example 4; FIG. 30 is an electron diffraction image of a portion indicated by * 1 in FIG. 29. FIG. FIG. 30 is an electron diffraction image of a portion * 2 in FIG. 29. FIG. 30 is an electron diffraction image of a portion * 3 in FIG. FIG. 30 is an electron diffraction image of a portion * 4 in FIG. 29. FIG. FIG. 30 is an electron diffraction image of a portion * 5 in FIG. 29. FIG. 10 is a graph showing the relationship between the cumulative input amount of Test Example 5 and the number of arcing operations.

  The present inventor has made it possible to deposit the deposit on the non-erosion portion of the target surface with good crystallinity from the beginning, and to deposit without substantially any void between the sputtering surface and the sputtering target. Then, the scattering of deposits is reduced, the number of cleanings can be reduced, and as a result, the target life can be improved and the manufacturing cost of the film can be reduced.

Further, according to the present invention, when a water adsorption layer is present on the sputtering surface of a sputtering target, a deposit on a non-erosion portion, for example, an ITO target, yellow powder such as indium oxide is stably and densely deposited. It has been completed based on the knowledge that it is difficult to peel off from the surface.
This is presumed to be based on the fact that when a water adsorbing layer is present, the deposit is deposited with good crystallinity from the beginning, so there is no difference in the thermal expansion coefficient over the entire deposit and there is no possibility of peeling. Is done. On the other hand, in the normal case, the deposit is first deposited as an amorphous layer, and then, for example, a few hundred nm is deposited to improve the crystallinity. As a result, a gap is formed between the surface and the sputtering surface, or peeling occurs.

That is, the present invention is a sputtering product in which deposits are deposited on a non-erosion part by being used for sputtering, and the deposits have good crystallinity at least up to a layer near the interface. In the target. The deposit on the non-erosion portion after being subjected to sputtering and having an energy of 50 Wh / cm ² or more is deposited with good crystallinity from the beginning, and there is substantially no void between the sputtering surface. The sputtering target is deposited without existing, and such a sputtering target is realized by having a water adsorption layer on the target surface. From the above, it is assumed that the sputtering target of the present invention is made of a material having crystallinity, particularly a ceramic target having crystallinity, and particularly preferably an ITO sputtering target.

  Here, the water-adsorbing layer is not observable as being wet with water by visual observation, but is such that the presence of water cannot be observed by visual observation. Distinguishing from a specific forming method, from the state where the target is wet with water, by drying by vacuum heat drying or heat drying, etc. without substantially completely removing water, for example, by blowing off water with air blow Is formed. If it is such a state, a formation method will not be specifically limited.

  For example, after the sputter surface is wetted with water, excess adhering water may be blown off with an air blow so that the presence of water cannot be visually observed. Here, wetting with water is not particularly limited, such as pouring water, immersing in water, spraying water, or contacting a water absorbing member that has absorbed water, but there is excess water on the surface. It means to make a state to do. For example, as described in JP-A-2005-42169, the surface may be wetted also as a surface treatment by spraying water at a predetermined pressure.

  Further, the water absorbing member that has absorbed water is a water absorbing member such as a foamed material such as sponge, a cloth material such as a woven fabric or a non-woven fabric, and the target surface is obtained by bringing the water into contact with the target surface. Water can adhere to the surface. In this case, when the surplus water adheres to the target surface and the surface becomes wet, for example, it is necessary to blow off surplus water by air blow to form a water adsorbing layer. Can also be made into a water-adsorbing layer by leaving it at room temperature and normal pressure without vacuum treatment or heating. Furthermore, depending on conditions, such as the contact method of an absorption member, a water adsorption layer can be formed only by making the absorption member which absorbed water contact.

  In the present invention, as the water used for forming the water adsorption layer, it is preferable to use water in which impurities are not substantially mixed and in which impurities are not dissolved, such as deionized water and distilled water. It is preferable to use so-called pure water. Of course, a liquid that does not affect the surface of the sputtering target, for example, a hydrophilic solvent such as various alcohols may be mixed and used, and is not limited to pure water.

  The water adsorbing layer of the present invention may be present on the sputtering surface of the target body of the sputtering target to be sputtered, particularly at least on the non-erosion portion, but may be present on the entire target body of the sputtering target.

  As described above, when the sputtering target of the present invention is wetted with the above-described water on the sputtering surface and the presence of water cannot be visually observed, a water adsorption layer is present on the sputtering surface. However, in order to scientifically confirm the presence of the water adsorption layer, for example, photoelectron analysis can be applied. That is, it is confirmed that the water adsorbing layer is present when the photoelectron yield is 400 count / sec or less when the sputter surface having the water adsorbing layer is irradiated with light having a wavelength of 6.6 eV photon energy. Can do. This principle is based on the fact that the photon generated from the sputtering surface is absorbed or scattered when photoelectrons are irradiated due to the presence of the water adsorbing layer, resulting in a decrease in the photon absorptance. If the water adsorbing layer is present, it is 400 count / sec or less, and for example, in the example described later, it is about 50 count / sec, but the lower limit is not particularly required. That is, if the presence of water can be observed visually, the photoelectron yield is expected to be very small, but this limitation is limited to the water adsorption layer, that is, the presence of water cannot be observed visually. It is not necessary to specify a lower limit.

When sputtering using a sputtering target having a water adsorbing layer in this way, the deposit on the non-erosion part is deposited with good crystallinity from the beginning and densely deposited on the sputter surface, so that it becomes a firmly attached state. It becomes difficult to peel off. Even after the energy of 50 Wh / cm ² or more has been input since the start of sputtering, there is substantially no void between the deposit on the non-erosion part and the target surface. Here, “substantially no void” means that the void between the deposit in the non-erosion portion and the target surface is 1 μm or less, preferably 500 nm or less, more preferably 200 nm. Voids of this size may be formed even when the deposits are densely deposited with good crystallinity, and there is very little possibility of causing peeling from such voids. This is because it does not indicate the state. In addition, since it is ideal and preferable that a space | gap does not exist substantially, it cannot be overemphasized that it is not necessary to specifically limit a lower limit.

  Therefore, when the sputtering target after being used for sputtering is observed, it can be confirmed whether the sputtering target according to the present invention has been used for sputtering or the sputtering method of the present invention has been implemented.

  Since the water adsorption layer of the sputtering target of the present invention is left in a released state at room temperature and normal pressure and is present on the target surface to the extent that it does not impair its effect even after a lapse of several days, the sputtering target manufacturing process Even when the water adsorbing layer is formed and packaged and shipped, the effect of the water adsorbing layer is manifested by mounting and using it as it is in the sputtering apparatus.

  In addition, the water adsorption layer of the sputtering target of the present invention is not necessarily provided in the sputtering target manufacturing process, and may be formed at least before the sputtering target is attached to the sputtering apparatus. A layer may be formed. Here, the term “immediately before” means to be performed near the site where the sputtering target to be installed in the sputtering apparatus is installed or in the vicinity of the factory, and includes a range of several minutes to several days ago.

  On the other hand, if the adsorption layer on the target surface is removed by drying or the like before the start of sputtering discharge, the effect is lost. For example, if the baking treatment is performed before the sputtering is started after the sputtering target of the present invention is mounted on the sputtering apparatus, the water adsorption layer may disappear before the sputtering starts. It is preferable not to perform the baking process. In addition, when baking at 50 degreeC or more, it is preferable to cool so that a target may be kept at less than 50 degreeC so that a water adsorption layer may not lose | disappear.

Moreover, the sputtering target of this invention is not limited to what is not used for sputtering, For example, after using it for sputtering for a fixed period, the target which gave the predetermined maintenance may be sufficient. That is, after performing a predetermined maintenance on a sputtering target that has been used for a predetermined period, for example, 50 Wh / cm ² or more, a water adsorbing layer is provided in the same manner as described above, so that subsequent deposits can be stably and densely formed. The target life after that is improved. The predetermined maintenance after use may be, for example, a process of surface polishing and washing with water, or a process of simply washing with water, and is not particularly limited.

  The sputtering target to which the present invention can be applied is not particularly limited, and can be suitably applied to a ceramic target made of an oxide or the like. In a ceramic target obtained by sintering such an oxide powder material, deposits deposited on the non-erosion portion are likely to be scattered, and therefore the present invention can be effectively applied. Among these, an ITO sputtering target made of an oxide containing indium oxide and tin oxide is required to have stability from the beginning to the middle and the latter in order to achieve efficient sputtering. Therefore, the present invention can be applied particularly effectively. .

  An example of a method for producing a sputtering target according to the present invention will be described using a ceramic target represented by ITO as an example.

  First, the raw material powder is mixed at a desired blending ratio, molded using various conventionally known wet methods or dry methods, and fired.

  Examples of the dry method include a cold press method and a hot press method. In the cold press method, a mixed powder is filled in a mold to produce a molded body, which is fired and sintered in an air atmosphere or an oxygen atmosphere. In the hot press method, the mixed powder is directly sintered in a mold.

  As the wet method, for example, a filtration molding method (see JP-A-11-286002) is preferably used. This filtration molding method is a filtration molding die made of a water-insoluble material for obtaining a compact by draining water from a ceramic raw material slurry under reduced pressure, and a molding lower die having one or more drain holes, The filter comprises a water-permeable filter placed on the molding lower mold and a molding mold sandwiched from the upper surface side through a sealing material for sealing the filter. The mold, sealing material, and filter are each assembled so that they can be disassembled, and the mixed powder, ion-exchanged water, and organic additive are added using a filtration mold that drains the water in the slurry under reduced pressure only from the filter surface side. A slurry made of an agent is prepared, this slurry is poured into a filtration mold, and the molded body is produced by draining the water in the slurry under reduced pressure only from the filter surface side. After 燥脱 butter, baking.

  In each method, the firing temperature is preferably 1300 to 1600 ° C., more preferably 1450 to 1600 ° C., for example, in the case of an ITO target. Thereafter, machining for forming / processing is performed to a predetermined dimension to obtain a target.

  In general, after molding, the surface is ground for thickness adjustment, and further, several steps of polishing are performed to smooth the surface. Moreover, after performing a surface treatment as needed, a water adsorption layer is formed.

  The method for forming the water adsorption layer is as described above. The formation of the water adsorption layer may be performed before the target body is bonded to the backing plate, but is preferably performed after bonding to the backing plate. This is for preventing as much as possible adhesion of dust and dirt on the water adsorbing layer, and after forming the water adsorbing layer, it is preferable to pack the adsorbed material so as not to adhere. In the case of packing with a resin film, it is preferable to use a resin film that does not contain detachable particles because the particles may be transferred to the surface of the target in contact with the resin film. It is preferable to perform packing so that nothing touches.

Example 1
From an ITO sintered body (composition: 10 wt% SnO ₂ -In ₂ O ₃ , raw material purity 99.99%) molded and fired by a filtration molding method according to JP-A-11-286002, with a diameter of 6 inches A target with a thickness of 6 mm was produced. The relative density of this target was around 99.3% with a true density of 7.155 g / cc. Subsequently, when grinding the surface of the target, a # 170 diamond grindstone was attached to a surface grinder to process the surface. Thereafter, the target was bonded to a copper backing plate with In. Polishing was performed with sandpaper to remove In that protruded around the target after bonding, In that adhered to the backing plate, and oxides of the backing plate. And in order to remove shavings, the surface of the target and the backing plate was wiped up with isopropyl alcohol (IPA).

  Thereafter, the target surface was washed with pure water, and surplus water on the target surface was blown off with nitrogen to blow away the water visually.

(Comparative Example 1)
The same ITO target as in Example 1 was finally washed with pure water, and then dried at 120 ° C. for 15 hours in a vacuum dryer evacuated by a rotary pump and a turbo pump to obtain a target of Comparative Example 1.

(Test Example 1)
The targets of Example 1 and Comparative Example 1 were mounted in a sputtering apparatus, and continuous sputtering was performed up to an integrated input power of 100 Wh / cm ² under the following conditions. During that time, the number of arcing that occurred during sputtering was counted using the arc counter of Landmark Technology. The results are shown in Table 1 and FIG.

Moreover, the external appearance photograph of the sputtering target after carrying out the continuous sputtering of the target of Example 1 and the comparative example 1 to 50 Wh / cm < ² > of integrated input electric power is shown in FIG.2 and FIG.3. Similarly, external appearance photographs after continuous sputtering up to an integrated input power of 75 Wh / cm ² are shown in FIGS.

Further, cross-sectional SEM photographs near the central part of the non-erosion part, which is a part where yellow powder is concentrically accumulated in FIGS. 2 and 3 of the integrated input power 50 Wh / cm ² of Example 1 and Comparative Example 1, respectively. 6 and FIG. Moreover, the cross-sectional SEM photograph of the central part vicinity of the non-erosion part which is a part which the yellow powder accumulate | stored concentrically in FIG.4 and FIG.5 of integrated input electric power 75Wh / cm < ² > is shown in FIG.8 and FIG.9, respectively.

(Sputtering conditions)
Target dimensions: 6 inch diameter, 6 mm thickness
Sputtering method: DC magnetron sputtering Exhaust device: Rotary pump + cryopump Ultimate vacuum: 3.0 × 10 ⁻⁷ [Torr]
Ar pressure: 3.0 × 10 ⁻³ [Torr]
Oxygen partial pressure: 3.0 × 10 ⁻⁵ [Torr]
Sputtering power: 300 W (Power density 1.6 Wh / cm ² )

  From the above results, it was confirmed that the presence of the water adsorbing layer significantly reduced the number of accumulated arcs, greatly improved the initial stability, and reduced the arc over the long term.

On the other hand, when the target surface photograph was compared between Example 1 with a water adsorbing layer and Comparative Example 1 without a water adsorption layer, it was confirmed that the former was less formed in the former than in the latter. Moreover, this difference can be confirmed visually from the integrated input power 50 Wh / cm ^2, it was found to be quite pronounced in 75Wh / cm ^2.

Furthermore, the deposit on the non-erosion part is densely deposited, the adhesion with the target surface is good, and there is a gap between the deposit and the target surface as in the case where there is no water adsorption layer. Not confirmed. Such a difference in adhesion can be confirmed from the accumulated input power of 50 Wh / cm ^{2. In} Comparative Example 1, a gap of about 2 μm was observed. Further, it was found that such a difference was preserved even when sputtered continuously, the difference became clearer at 75 Wh / cm ² , and a gap of about 4 μm was observed in Comparative Example 1. In Comparative Example 1, this tendency was confirmed in the yellow powder accumulation portion on the outer side of the target.

(Comparative Example 2)
The same ITO target as in Example 1 was washed with water, and the target with water attached to the surface with the naked eye was used as the target of Comparative Example 2. This was installed in a vacuum apparatus and an attempt was made to evacuate. However, it was not possible to switch to the main pump during a normal evacuation time, and the vacuum was not able to be sputtered.

(Example 2)
An ITO target test piece 50 mm × 50 mm × 2 mm (thickness) produced in the same manner as in Example 1 was formed in the same manner as in Example 1 to form a water adsorption layer and left as it was at room temperature in the atmosphere for 44 hours. 2.

(Comparative Example 3)
A water adsorption layer was formed in the same manner as in Example 1 using ITO target test pieces 50 mm × 50 mm × 2 mm (thickness) produced in the same manner as in Example 1. Immediately after that, it was heated and dried at 120 ° C. for 15 hours in a vacuum dryer equipped with a turbo molecular pump, then left for 25 hours in vacuum and then left for 4 hours at room temperature in the atmosphere as Comparative Example 3.

(Test Example 2)
The samples of Example 2 and Comparative Example 3 were evaluated using an atmospheric photoelectron spectrometer (AC-3, manufactured by Riken Keiki Co., Ltd.). The measurement conditions are as follows.

Measurement light quantity [nW]: 49.7
Set light intensity [nW]: 50
Counting time [sec]: 10
Anode voltage [V]: 2990
Dead time [sec]: 0.00545
Starting energy [eV]: 5.5
End energy [eV]: 7
Step [eV]: 0.05
The result is shown in FIG. FIG. 10 shows the photon energy [eV] irradiated on the sample on the horizontal axis, and the photoelectron yield (yield) [count / sec] (cps) normalized by the energy and the light amount on the vertical axis.

  As a result, in Comparative Example 3, the photoelectron yield is high because there is no water adsorbing layer, and the photoelectron yield when irradiated with light having a photon energy of 6.6 eV is 445.3 [count. / Sec]. On the other hand, in Example 2, since there was a water adsorption layer, the photoelectron yield was suppressed from the former, and it was found that it was one-tenth that of Comparative Example 3 where the energy of the irradiated light was particularly high. . And the photon yield when irradiating the light of the wavelength which has a photon energy of 6.6 eV was 53.9 [count / sec].

(Test Example 3)
The targets of Example 1 and Comparative Example 1 were mounted in a sputtering apparatus, and continuous sputtering was performed up to an integrated input power of 110 Wh / cm ² under the same conditions as in Test Example 1. The surface of the non-erosion part of the target after use was impregnated with a resin, a sample for TEM was cut out by FIB, and cross-sectional observation was performed by FE-TEM. The results are shown in FIGS.

  Here, the TEM observation was performed using a transmission electron microscope (HF-2000, H-9000NAR manufactured by Hitachi, Ltd.) under the following observation conditions.

Acceleration voltage: 200 kV, 300 kV
Overall magnification: 15000 times In addition, an electron beam diffraction image obtained by a micro electron beam diffraction method is observed under the following conditions using a transmission electron microscope (HF-2000 manufactured by Hitachi, Ltd.).

Acceleration voltage: 200 kV
Camera length: 0.8m
Beam diameter: about 1nmφ
FIG. 11 is a cross-sectional photograph of the vicinity of the interface between the target surface and the deposit of Example 1, and FIGS. 12 to 16 are electron diffraction images of the portions * 1 to * 5 in FIG. As a result, all electron beam diffraction images of * 1 to * 5 showed a state of good crystallinity, and it was recognized that all the portions were single crystals. That is, it was recognized that the portion of * 2 which is a deposited layer near the target surface is also a layer having good crystallinity.

  FIG. 17 is a cross-sectional photograph of the vicinity of the interface between the target surface and the deposit in Comparative Example 1, and FIGS. 18 to 22 are electron diffraction images of portions * 1 to * 5 in FIG. As a result, an electron diffraction pattern other than * 2 showed a good crystallinity, but a ring pattern was observed at the location of * 2 which is a deposited layer near the target surface, indicating that it was an amorphous layer. Admitted.

(Example 3)
The target of Example 1 was continuously sputtered to an integrated input power of 50 Wh / cm ² under the same conditions as in Test Example 1, followed by maintenance only with water washing, and then the excess water on the target surface was blown off with nitrogen. The target was Example 3 with no moisture.

Example 4
After the target of Comparative Example 1 was continuously sputtered to the cumulative input power of 50 Wh / cm ² under the same conditions as in Test Example 1, maintenance was performed only with water washing, and then excess water on the target surface was blown off with nitrogen. The target was Example 3 with no moisture.

(Comparative Example 4)
In a vacuum dryer in which the target of Example 1 is continuously sputtered to an integrated input power of 50 Wh / cm ² under the same conditions as in Test Example 1, followed by maintenance only with water washing, and then evacuating with a rotary pump and a turbo pump. And dried at 120 ° C. for 15 hours to obtain a target of Comparative Example 4.

(Comparative Example 5)
In a vacuum dryer in which the target of Comparative Example 1 is continuously sputtered to an integrated input power of 50 Wh / cm ² under the same conditions as in Test Example 1, followed by maintenance only with water washing, and then evacuating with a rotary pump and a turbo pump. And dried at 120 ° C. for 15 hours to obtain a target of Comparative Example 5.

(Test Example 4)
The targets of Example 3 and Comparative Example 5 were mounted in the sputtering apparatus, and continuous sputtering was performed up to an integrated input power of 50 Wh / cm ² under the same conditions as in Test Example 1. The surface of the non-erosion part of the target after use was impregnated with a resin, a sample for TEM was cut out by FIB, and cross-sectional observation was performed by FE-TEM. The results are shown in FIGS.
FIG. 23 is a cross-sectional photograph of the vicinity of the interface between the target surface and the deposit in Example 3, and FIGS. 24 to 28 are electron diffraction images of portions * 1 to * 5 in FIG. As a result, all electron beam diffraction images of * 1 to * 5 showed a state of good crystallinity, and it was recognized that all the portions were single crystals. That is, it was recognized that the portion of * 2 which is a deposited layer near the target surface is also a layer having good crystallinity.

  29 is a cross-sectional photograph of the vicinity of the interface between the target surface and the deposit in Comparative Example 5, and FIGS. 30 to 34 are electron diffraction images of the portions * 1 to * 5 in FIG. As a result, the electron diffraction patterns other than * 2 and * 3 showed a good crystallinity, but the ring pattern was observed at a location near 600 nm from the interface of the location of * 2 which is a deposited layer near the target surface. Was observed and was found to be an amorphous layer.

(Test Example 5)
The targets of Examples 3 and 4 and Comparative Examples 4 and 5 were mounted in a sputtering apparatus, and continuous sputtering was performed up to an integrated input power of 50 Wh / cm ² under the same conditions as in Test Example 1. During that time, the number of arcing that occurred during sputtering was counted using the arc counter of Landmark Technology. The result is shown in FIG.

  As a result, in Examples 3 and 4 where the water adsorbing layer was formed and used for sputtering, regardless of the state before the intermediate maintenance, the cumulative number of occurrences of arcing is small, and the target life is improved. Admitted. On the other hand, in the case of Comparative Examples 4 and 5 in which there was no water adsorption layer after washing with water, the cumulative number of arcing was larger than in Examples 3 and 4, and it was confirmed that the target life was short.

Claims (24)

A sputtering target which is subjected to sputtering and deposits on a non-erosion portion, and the deposit is deposited with good crystallinity to at least a layer near the interface. 2. The sputtering target according to claim 1, wherein the layer in the vicinity of the interface is a region from the interface to near 100 nm, and the region is a crystal layer having good crystallinity. The deposit on the non-erosion part after the energy of 50 Wh / cm ² or more is supplied for sputtering is deposited without substantially any void between the sputtering surface. Sputtering target characterized. The sputtering target according to claim 3, wherein a gap between the deposit and the sputtering surface is 1 μm or less. A sputtering target comprising a water adsorption layer on a sputtering surface of the target. The sputtering target according to claim 5, wherein the water adsorption layer is present at least in a non-erosion portion of the sputtering surface. The sputtering target according to claim 5 or 6, wherein the water adsorption layer is formed by wetting a sputtering surface with water and then blowing off excessively attached moisture by air blow. target. The sputtering target according to claim 5 or 6, wherein the water adsorption layer is formed by bringing a water absorbing member that has absorbed water into contact therewith. The sputtering target according to any one of claims 5 to 8, wherein the water-adsorbing layer contains water to such an extent that it cannot be visually observed. 10. The sputtering target according to claim 5, wherein the sputtering surface having the water adsorption layer has a photoelectron yield of 400 count / sec when irradiated with light having a wavelength having a photon energy of 6.6 eV. A sputtering target characterized by: The sputtering target according to any one of claims 5 to 10, wherein the sputtering target is packaged and shipped after forming the water adsorption layer. The sputtering target according to claim 5, wherein the water adsorption layer is formed immediately before the start of sputtering discharge. The sputtering target according to any one of claims 5 to 12 is subjected to sputtering and deposits are deposited on a non-erosion part, and the deposits are deposited with good crystallinity at least to a layer near the interface. A sputtering target characterized by being made. 14. The sputtering target according to claim 13, wherein the layer in the vicinity of the interface is a region from the interface to near 100 nm, and the region is a crystal layer having good crystallinity. It is a thing after the sputtering target of any one of Claims 5-12 is used for sputtering and energy of 50 Wh / cm < ² > or more is thrown in, and the deposit to a non-erosion part is between sputtering surfaces. The sputtering target is characterized by being deposited without substantially any voids. The sputtering target according to claim 15, wherein a gap between the deposit and the sputtering surface is 1 μm or less. A method for producing a sputtering target, comprising the step of forming a water adsorption layer on the sputtering surface of the target. The method for manufacturing a sputtering target according to claim 17, wherein the water adsorption layer is formed at least on a non-erosion portion of a sputtering surface. 19. The method of manufacturing a sputtering target according to claim 17 or 18, wherein the water adsorption layer is formed by wetting a sputter surface of the target with water and then blowing off excessively attached moisture by air blow. A method for producing a sputtering target. 20. The method of manufacturing a sputtering target according to claim 19, wherein the step of wetting with water is performed by pouring water, immersing in water, spraying water, or contacting a water absorbing member that has absorbed water. A method for producing a sputtering target, comprising: 19. The method of manufacturing a sputtering target according to claim 17, wherein the water adsorption layer is formed by contacting a water absorbing member that has absorbed water. The method for manufacturing a sputtering target according to any one of claims 17 to 21, wherein the water adsorption layer contains water to an extent that cannot be visually observed. 23. The method of manufacturing a sputtering target according to claim 17, wherein a surface having the water adsorption layer has a photoelectron yield of 400 count when irradiated with light having a wavelength having a photon energy of 6.6 eV. / Sec or less, The manufacturing method of the sputtering target characterized by the above-mentioned. In the manufacturing method of the sputtering target of any one of Claims 17-23, after joining a target main body to a backing plate, the process of forming the said water adsorption layer is implemented, and it packs after that, It is characterized by the above-mentioned. A method for manufacturing a sputtering target.

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