TWI593810B - Sputtering target - Google Patents

Description

Sputter target

The present invention relates to a sputtering target for use in forming a magnetic film of a magnetic recording medium.

In the field of magnetic recording represented by a hard disk drive machine, a magnetic film material of a magnetic recording medium has been using a material having a ferromagnetic metal Co, Fe or Ni as a base. For example, a magnetic film of a hard disk using a horizontal magnetic recording method is a Co-Cr-based or Co-Cr-Pt-based ferromagnetic alloy containing Co as a main component.

Further, a magnetic material of a hard disk having a perpendicular magnetic recording method which has been put into practical use in recent years is often a composite material composed of a Co-Cr-Pt-based ferromagnetic alloy having a main component of Co and an oxide. Further, since the magnetic properties are high, the magnetic thin film is often produced by sputtering a sputtering target having the above-mentioned material as a component by a magnetron sputtering apparatus.

On the other hand, the recording density of hard disks has rapidly increased year by year, exceeding 1 Tbit/in ² . If the recording density reaches 1 Tbit/in ² , the size of the recording bit will be less than 10 nm, and it is expected that superparamagnetization caused by thermal fluctuations in this case will become a problem. It is expected that the magnetic recording medium material currently used is not sufficient for a material in which a P-based alloy is added to a Co-based alloy to increase crystal magnetic anisotropy. The reason for this is that magnetic particles which are stably magnetized with a size of 10 nm or less are required to have higher crystal magnetic anisotropy.

For the above reasons, an Fe-Pt alloy having an L1 ₀ structure has been attracting attention as a material for an ultrahigh-density recording medium. The Fe-Pt alloy having the L1 ₀ structure not only has high crystal magnetic anisotropy, but also has excellent corrosion resistance and oxidation resistance, and therefore is expected to be suitable as a material for a magnetic recording medium.

However, the Fe-Pt film formed by the sputtering method is an irregular phase of a quasi-stable phase, and in order to develop the L1 ₀ structure of the regular phase, heat treatment must be performed at a regularized temperature. Since this regularizing temperature is high, the problem of heat resistance of the substrate occurs. Therefore, attempts have been made to add Ag or Cu to the Fe-Pt alloy to lower the regularization temperature.

Further, when the Fe-Pt alloy is used as a material for an ultra-high-density recording medium, it is required to develop a technique in which the Fe-Pt alloy is as high-density and uniform in direction as the magnetic particles of the L1 ₀ structure in a magnetic isolation state. Disperse.

Therefore, a granular structured magnetic film in which magnetic particles are isolated by a non-magnetic material such as an oxide or carbon has been proposed as a magnetic recording medium for a next-generation hard disk. The granular magnetic film is a structure in which magnetic particles are magnetically insulated from each other by a non-magnetic substance. A magnetic recording medium having a magnetic film of a granular structure and a related document related thereto, for example, Patent Document 1 can be cited.

Such a granular magnetic film is conventionally prepared by co-sputtering a target made of a different material. However, since the common sputtering apparatus is expensive and the apparatus itself is large, a magnetic thin film is usually produced by using a sputtering type target composed of an Fe-Pt-based alloy and a non-magnetic material in mass production. And such a target is produced by a powder sintering method.

However, when the sputtering target composed of the Fe-Pt-based alloy and C is sputtered, the sputtering surface C is easily detached, and the problem of adhesion to the substrate occurs. This attachment is called a particle. As the recording density of the hard disk drive is increased, the floating amount of the magnetic head becomes smaller, so The size and number of particles in a magnetic recording medium are increasingly restricted.

The following is a disclosure of a patent document relating to a sputtering target for a recording medium using an Fe-Pt-based material.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-152471

Patent Document 2: Japanese Laid-Open Patent Publication No. 2003-313659

Patent Document 3: Japanese Laid-Open Patent Publication No. 2011-210291

Patent Document 4: Japanese Patent No. 50412262

Patent Document 5: Japanese Patent No. 5041261

Patent Document 6: Japanese Laid-Open Patent Publication No. 2012-214874

An object of the present invention is to provide a sputtering target comprising an Fe-Pt-based alloy and Ag and C, which can greatly reduce the amount of particles generated during sputtering.

In order to solve the problem, the inventors of the present invention have found that the amount of particles generated during sputtering can be greatly reduced by adjusting the composition and structure of the sputtering target. Further, in the present invention, when the structure of the target is analyzed, since the cross section perpendicular to the target sputter surface is used, the target cross section or the cut surface to be described later means a cross section perpendicular to the sputter surface.

Based on this insight, the present invention provides:

1) A sputtering target comprising an Fe-Pt-based alloy phase, an Ag phase, and a C phase, wherein a value obtained by dividing a C atom number ratio by an Ag atom number ratio in a composition of a sputtering target as a whole In the cross section of the sputtering target, the Ag phase is included in all the imaginary circles having a radius of 10 μm centered on any point in the Ag phase, or the Ag phase has the following shape: The circle has a tangent or intersection of at least 2 points or more between the outer edge of the Ag phase.

2) The sputtering target according to the above 1), wherein the area ratio of the C phase in the cross section of the sputtering target is 10% or more and 45% or less.

3) A sputtering target comprising an Fe-Pt-based alloy phase, an Ag phase, a C-phase, and an oxide phase, wherein the ratio of the number of C atoms is divided by the number of Ag atoms in the composition of the entire sputtering target The value obtained by the ratio is 4 or more and 10 or less. In the cross section of the sputtering target, the Ag phase is included in all imaginary circles having a radius of 10 μm centered on an arbitrary point in the Ag phase, or the Ag phase has the following shape : There is a tangent or intersection point of at least 2 points between the imaginary circle and the outer edge of the Ag phase.

4) The sputtering target according to the above 3), wherein the oxide phase is selected from the group consisting of Al, B, Ba, Be, Bi, Ca, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe , Ga, Gd, Ge, Hf, Ho, La, Li, Lu, Mg, Mo, Nb, Nd, Ni, Pr, Sb, Sc, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tm One or more elements of V, W, Y, Yb, Zn, and Zr are oxides of constituent components.

5) The sputtering target according to the above 3) or 4), wherein the area ratio of the C phase to the oxide phase in the cross section is 10% or more and 45% or less in total.

The sputtering target according to any one of the above 1), wherein the sputtering target is selected from the group consisting of Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh. One or more elements of Ru, Sn, Ta, W, V, and Zn are used as the metal component, and the content thereof is 0.5% or more and 15% or less in terms of the ratio of the number of atoms in the metal component.

According to the present invention, it is possible to provide a sputtering target which greatly reduces the amount of particles generated at the time of sputtering. Therefore, it has an excellent effect of improving the yield at the time of sputtering film formation.

Fig. 1 is a schematic view showing an example of the shape of the Ag phase of the present invention.

Fig. 2 is a schematic view showing an example of the shape of an Ag phase outside the scope of the present invention.

Fig. 3 is a view showing a secondary electron image and an element distribution image when the cross section of the sputtering target of Example 1 was observed by an electron probe microanalyzer (EPMA).

The sputtering target of the present invention is characterized by comprising an Fe-Pt-based alloy phase, an Ag phase, and a C phase. Here, the Fe-Pt-based alloy phase refers to an alloy containing Fe and Pt as a main component, and contains Fe and Pt as a main component and contains Fe and Fe, in addition to a ternary alloy containing only Fe and Pt. An alloy of three or more elements of a metal element other than Pt. Examples of the alloy of the ternary system or higher include Fe-Pt-Cu.

Further, the sputtering target of the present invention is characterized in that the value of the ratio of the number of C atoms divided by the ratio of the number of Ag atoms in the composition of the entire sputtering target is 4 or more and 10 or less. The Ag phase has an effect of suppressing C detachment of the target surface during sputtering and remarkably suppressing generation of particles. According to the study by the inventors of the present invention, if the value obtained by dividing the C atom number ratio by the Ag atom number ratio is less than 4, the effect of suppressing the generation of particles is remarkably greatly reduced. Further, when the value is larger than 10, although the effect of suppressing generation of particles is suppressed, Ag segregation occurs in the sputtering film, and the magnetic properties of the magnetic film are impaired.

Further, in the sputtering target of the present invention, the Ag phase is included in all imaginary circles having a radius of 10 μm which is drawn around an arbitrary point in the Ag phase, or the Ag phase has the following shape. : There is a tangent or intersection point of at least 2 points between the imaginary circle and the outer edge of the Ag phase. This feature refers to the fact that there is almost no coarse Ag phase in the target tissue. If a coarse Ag phase is present in the target tissue, the following problem occurs: Ag at a high sputtering rate selectively It is sputtered and damages the smoothness of the sputtered surface, increasing the amount of particles. However, even in the case where there is a coarse Ag phase which does not have the above shape, the effect of the present invention can be obtained if the area ratio is less than 20% with respect to the entire Ag phase.

Further, in the sputtering target of the present invention, the area ratio of the C phase in the cross section is preferably 10% or more and 45% or less. If the area ratio of the C phase is less than 10%, C may not sufficiently insulate the magnetic interaction between the magnetic particles in the sputtering film, and thus good magnetic properties may not be obtained. Further, in the case of more than 45%, C may aggregate and cause a coarse C phase in the target tissue, and the generation of particles may increase. Further, in order to reduce the variation in the area ratio of the C phase, it is preferable to observe a plurality of cross sections of about 1 mm ^{2 in} total, and obtain the average ratio from the average.

The sputtering target of the present invention may further contain an oxide phase in a structure composed of an Fe-Pt-based alloy phase, an Ag phase, and a C phase. The oxide phase is effective in insulating the magnetic interaction between the magnetic particles in the same manner as in the sputtering film.

Further, the oxide phase may be selected from the group consisting of Al, B, Ba, Be, Bi, Ca, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Ho, La, Li, Lu, Mg, Mo, Nb, Nd, Ni, Pr, Sb, Sc, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tm, V, W, Y, Yb, One or more elements of Zn and Zr are oxides of constituent components. These can be arbitrarily selected depending on the desired magnetic characteristics.

Further, in the present invention, the area ratio of the C phase to the oxide phase in the sputtering target containing the oxide phase is preferably 10% or more and 45% or less in total. When the total area ratio of the C phase to the oxide phase is less than 10%, the C phase and the oxide cannot sufficiently insulate the magnetic interaction between the magnetic particles in the sputtering film, so that good magnetic properties cannot be obtained. . Further, when it is more than 45%, the C phase and the oxide may aggregate to form a coarse phase C or an oxide phase in the target structure, and the generation of particles may increase. Further, in order to reduce the variation in the area ratio of the C phase and the oxide phase, it is preferable to observe a plurality of cross sections having a total of about 1 mm ² and to obtain the average cross section.

Further, the sputtering target of the present invention preferably contains a material selected from the group consisting of Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, Sn, Ta, W, One or more metal elements in V and Zn. Further, the content thereof is preferably 0.5 to 15% in terms of the ratio of the number of atoms in the metal component. Such added metals are primarily added to reduce the heat treatment temperature used to visualize the L1 ₀ structure. If the content is less than 0.5%, it is difficult to obtain the above-described effects. On the other hand, if it is more than 15%, the magnetic properties of the magnetic film may be impaired.

The sputtering target of the present invention is produced by a powder sintering method. For example, it can be produced by the following method.

First, Fe powder, Pt powder, Ag powder, and metal powder added as needed are prepared as metal powder. At this time, not only a single element of metal powder but also an alloy powder can be used. For these metal powders, those having an average particle diameter of 1 to 10 μm should be used. When the average particle diameter is 1 to 10 μm, the mixture can be more uniformly mixed, and segregation and coarse crystallization in the target structure can be prevented. On the other hand, when the average particle diameter of the metal powder exceeds 10 μm, the C phase and the oxide phase may not be uniformly dispersed, and if it is less than 1 μm, the influence of oxidation of the metal powder may cause a problem. However, this particle size range is a preferred condition and does not deny the present invention beyond this range. Further, the Ag powder has strong cohesiveness due to particle size or shape. In this case, it is preferred to use a coating process which has been subjected to prevention of aggregation.

Further, the C powder should preferably be one having an average particle diameter of 1 to 30 μm. When the average particle diameter is 1 to 30 μm, when mixed with the metal powder, the C powders are less likely to aggregate, and the C phase can be uniformly dispersed. However, this particle size range is a preferred condition and does not deny the present invention beyond this range. As the type of the C powder, those having a crystal structure like a graphite or a nanotube and an amorphous one represented by carbon black can be used as the C powder.

Further, it is preferable to use an oxide powder of an average particle diameter of 0.2 to 5 μm. If the average particle diameter is 0.2 to 5 μm, there is an advantage that it can be easily mixed with the metal powder easily. On the other hand, when the average particle diameter of the oxide powder exceeds 5 μm, a coarse oxide phase may be generated after sintering, and if it is less than 0.2 μm, the oxide powder may aggregate with each other. However, this particle size range is a preferred condition and does not deny the present invention beyond this range.

Next, the raw material powder is weighed into a desired composition, and pulverized and mixed at the same time using a known method such as a ball mill. At this time, it is preferred to put an inert gas in the pulverization container to suppress oxidation of the raw material powder.

The mixed powder obtained in the above manner is molded and sintered by a hot press method in a vacuum atmosphere or an inert gas atmosphere. Further, in addition to the above-described hot pressing, various pressure sintering methods such as a plasma discharge sintering method can also be used. In particular, the hot hydrostatic sintering method is effective for increasing the density of the sintered body.

The holding temperature at the time of sintering depends on the constituent components of the target, but in most cases, it is preferably in the temperature range of 500 to 950 °C. Further, in order to realize that the Ag phase is smaller than all imaginary circles having a radius of 10 μm centered on an arbitrary point in the Ag phase in the cross section of the target, or at least two points or more between the imaginary circle and the outer edge of the Ag phase Or the shape of the intersection point should be such that the temperature is below 900 °C. The reason is that when the temperature is 900 ° C or higher, Ag particles grow and it becomes difficult to satisfy the above characteristics.

The sintered body obtained in the above manner is processed into a desired target shape by a lathe or the like, whereby the sputtering target of the present invention can be produced.

The sputtering target produced in the above manner has an excellent effect of improving the yield at the time of film formation because the amount of particles generated at the time of sputtering can be reduced.

Example

Hereinafter, it demonstrates based on an Example and a comparative example. In addition, the embodiment and the like are merely examples, and are not limited by the examples. That is, the present invention is limited only by the scope of the patent application, and includes various modifications other than the embodiments included in the invention.

(Example 1)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, and C powder (graphite powder) having an average particle diameter of 10 μm were prepared as raw material powders. In order to prevent aggregation, the Ag powder is used as a coating process by an organic material.

Then, the total weight was 2,500 g in the following composition ratio.

Weighing composition (mole fraction): 30Fe-30Pt-5Ag-35C

Next, in a Ar environment, the weighed powder was sealed with a zirconia ball of a pulverizing medium in a ball mill pot having a capacity of 10 liters, and mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. Moreover, it is naturally cooled directly in the chamber after the end of the hold.

A part of the sintered body obtained in the above manner was cut out, and the cut surface thereof was ground and observed with an electron probe microanalyzer (EPMA). As a result, the structure in which the Fe-Pt alloy phase, the Ag phase, and the C phase were uniformly dispersed was confirmed. Furthermore, as a result of observing the range of 0.2 mm ² by EPMA, it was confirmed that all of the imaginary circles having a radius of 10 μm, which is centered on an arbitrary point in the Ag phase, are 80% or more of the Ag phase. Or having a shape having a tangent point or an intersection point of at least 2 points or more between the imaginary circle and the outer edge of the Ag phase. Further, as a result of obtaining a C-phase area ratio from an image in a range of 1 mm ² observed by an optical microscope, it was 25.5%.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, and Ag were measured using an ICP-AES apparatus, and C was measured by a carbon analyzer using a high-frequency induction heating furnace-infrared absorption method. As a result of calculating the atomic ratio from the weight ratio obtained in this manner, the value obtained by dividing the ratio of the number of C atoms by the ratio of the number of Ag atoms was 6.9.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. The target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by CANON ANELVA) for sputtering.

The sputtering conditions were such that the input electric power was 1 kW, the Ar gas pressure was 1.7 Pa, and after 2 kWhr of pre-sputtering, film formation was performed on a 4 吋 diameter Si substrate for 20 seconds. The number of particles attached to the substrate is then measured with a particle counter. As a result, the number of particles was 83.

(Comparative Example 1)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, and C powder (graphite powder) having an average particle diameter of 10 μm were prepared as raw material powders. In order to prevent aggregation, the Ag powder is used as a coating process by an organic material.

Then, the total weight was 2,500 g in the following composition ratio.

Weighing composition (mole fraction): 30Fe-30Pt-2Ag-38C

Next, in a Ar environment, the weighed powder was sealed with a zirconia grinding ball of a pulverizing medium in a ball pulverizer having a capacity of 10 liters, and mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. Make The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

A part of the sintered body obtained in the above manner was cut out, the cross section was ground, and observed by an electron probe microanalyzer (EPMA). As a result, the structure in which the Fe-Pt alloy phase, the Ag phase, and the C phase were uniformly dispersed was confirmed. Furthermore, as a result of observing the range of 0.2 mm ² by EPMA, it was confirmed that all of the imaginary circles having a radius of 10 μm, which is centered on an arbitrary point in the Ag phase, are 80% or more of the Ag phase. Or having a shape having a tangent point or an intersection point of at least 2 points or more between the imaginary circle and the outer edge of the Ag phase. Further, the C-phase area ratio was determined from an image in the range of 1 mm ² observed by an optical microscope, and was 28.4%.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, and Ag were measured using an ICP-AES apparatus, and C was measured by a carbon analyzer using a high-frequency induction heating furnace-infrared absorption method. The atomic ratio was calculated from the weight ratio obtained in this manner, and the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and as a result, it was 18.5. This value is not within the scope of the request in this case.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. This target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Annehua), and sputtering was performed under the same conditions as in Example 1. As a result, the number of particles was 561, and the number of particles was significantly increased as compared with Example 1.

(Comparative Example 2)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 30 μm, and C powder (graphite powder) having an average particle diameter of 10 μm were prepared as raw material powders. Then with the following The composition ratio was weighed to a total weight of 2,500 g.

Weighing composition (mole fraction): 30Fe-30Pt-5Ag-35C

Next, in a Ar environment, the weighed powder was sealed with a zirconia grinding ball of a pulverizing medium in a ball pulverizer having a capacity of 10 liters, and mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 960 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

A part of the sintered body obtained in the above manner was cut out, the cross section was ground, and observed with an electron probe microanalyzer. As a result, the structure in which the Fe-Pt alloy phase, the Ag phase, and the C phase were uniformly dispersed was confirmed. Further, as a result of observing the range of 0.2 mm ² , a coarse Ag phase was observed, and it was confirmed that the Ag phase was included in all the imaginary circles having a radius of 10 μm centered on any point in the phase, or the Ag phase was not provided. The shape of "the tangent point or the intersection point of at least 2 points or more between the imaginary circle and the outer edge of the Ag phase" accounts for 20% or more of the entire area of the Ag phase by the area ratio. The reason for this is considered to be the use of a large particle size Ag powder and a high sintering temperature. Further, as a result of obtaining a C-phase area ratio from an image in a range of 1 mm ² observed by an optical microscope, it was 25.5%.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, and Ag were measured using an ICP-AES apparatus, and C was measured by a carbon analyzer using a high-frequency induction heating furnace-infrared absorption method. The atomic ratio was calculated from the weight ratio obtained in this manner, and the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and as a result, it was 7.0.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. Mount the target on a magnetron sputtering device (Canon Annewa C -3010 sputtering system), sputtering was carried out under the same conditions as in Example 1. As a result, the number of particles was 245, and the number of particles was increased as compared with Example 1.

(Comparative Example 3)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, and C powder (graphite powder) having an average particle diameter of 10 μm were prepared as raw material powders. In order to prevent aggregation, the Ag powder is used as a coating process by an organic material.

Then, the combined weight was 1800 g in the following composition ratio.

Weighing composition (mole fraction): 17Fe-17Pt-6Ag-60C

Next, in a Ar environment, the weighed powder was sealed with a zirconia grinding ball of a pulverizing medium in a ball pulverizer having a capacity of 10 liters, and mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

The cross section of the sintered body obtained in the above manner was polished, and observed by an electron probe microanalyzer (EPMA), and the structure in which the Fe-Pt alloy phase, the Ag phase, and the C phase were uniformly dispersed was confirmed. Further, as a result of observing the range of 0.2 mm ² by EPMA, it was confirmed that all the imaginary circles having a radius of 10 μm formed around an arbitrary point in the Ag phase were contained in an area ratio of 80% or more of the Ag phase. Or having a shape having a tangent point or an intersection point of at least 2 points or more between the imaginary circle and the outer edge of the Ag phase. Further, as a result of obtaining a C-phase area ratio from an image in a range of 1 mm ² observed by an optical microscope, the C-phase area ratio was 48.1%. This value is outside the scope of the request in this case.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, and Ag were measured using an ICP-AES apparatus, and C was measured by an oxygen analyzer using an inert gas melting-infrared absorption method. As a result of calculating the atomic ratio from the weight ratio obtained in this manner, the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and as a result, it was 9.8.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. This target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Annehua), and sputtering was performed under the same conditions as in Example 1. As a result, the number of particles was 880, and the number of particles was significantly increased as compared with Example 1.

(Example 2)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, C powder (graphite powder) having an average particle diameter of 10 μm, and SiO ₂ powder having an average particle diameter of 1 μm were prepared as a raw material powder. In order to prevent aggregation, the Ag powder is used as a coating process by an organic material.

Then, the total weight was 2,200 g in the following composition ratio.

Weighing composition (mole fraction): 30Fe-30Pt-5Ag-30C-5SiO ₂

Next, in a Ar environment, the weighed powder was sealed with a zirconia grinding ball of a pulverizing medium in a ball pulverizer having a capacity of 10 liters, and mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

A part of the sintered body obtained in the above manner was cut out, and the cut surface thereof was ground and observed with an electron probe microanalyzer (EPMA). As a result, the structure in which the Fe-Pt alloy phase, the Ag phase, the C phase, and the oxide (SiO ₂ ) phase were uniformly dispersed was confirmed. Further, as a result of observing the range of 0.2 mm ² by EPMA, it was confirmed that all the imaginary circles having a radius of 10 μm formed around an arbitrary point in the Ag phase were contained in an area ratio of 80% or more of the Ag phase. Or having a shape having a tangent point or an intersection point of at least 2 points or more between the imaginary circle and the outer edge of the Ag phase. Further, the area ratio of the C phase to the oxide phase was determined from an image in the range of 1 mm ² observed by an optical microscope, and was 35.5%.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, Ag, and Si are measured using an ICP-AES device, and C is measured by a carbon analysis device using a high-frequency induction heating furnace-infrared absorption method, and O is using an inert gas melting-infrared absorption method. An oxygen analyzer is used to measure. The atomic ratio was calculated from the weight ratio obtained in this manner, and the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and the result was 6.0.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. This target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Annehua), and sputtering was performed under the same conditions as in Example 1. As a result, the number of particles was 34.

(Comparative Example 4)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, C powder (graphite powder) having an average particle diameter of 10 μm, and SiO ₂ powder having an average particle diameter of 1 μm were prepared as a raw material powder. In order to prevent aggregation, the Ag powder is used as a coating process by an organic material.

Then, the total weight was 2,300 g in the following composition ratio.

Weighing composition (mole fraction): 32.5Fe-32.5Pt-2Ag-28C-5SiO ₂

Next, in the Ar environment, weigh the powder and the zirconia mill of the pulverizing medium. The balls were closed together in a ball mill having a capacity of 10 liters, and were mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

The cross section of the sintered body obtained in the above manner was ground and observed by an electron probe microanalyzer (EPMA) to confirm the Fe-Pt alloy phase, the Ag phase, the C phase, and the oxide (SiO ₂ ). A tissue structure that is uniformly dispersed with each other. Further, as a result of observing the range of 0.2 mm ² by EPMA, it was confirmed that all the imaginary circles having a radius of 10 μm formed around an arbitrary point in the Ag phase were contained in an area ratio of 80% or more of the Ag phase. Or having a shape having a tangent point or an intersection point of at least 2 points or more between the imaginary circle and the outer edge of the Ag phase. Further, the area ratio of the C phase to the oxide phase was determined from an image in the range of 1 mm ² observed by an optical microscope, and was 34.2%.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, Ag, and Si are measured using an ICP-AES device, and C is measured by a carbon analysis device using a high-frequency induction heating furnace-infrared absorption method, and O is using an inert gas melting-infrared absorption method. An oxygen analyzer is used to measure. The atomic ratio was calculated from the weight ratio obtained in this manner, and the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and as a result, it was 13.9. This value is outside the scope of the request in this case.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. This target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Annehua), and sputtering was carried out under the same conditions as in Example 2. As a result, the number of particles There were 189 particles, and the number of particles was significantly increased compared with Example 2.

(Comparative Example 5)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, and C powder (graphite powder) having an average particle diameter of 10 μm were prepared as raw material powders. In order to prevent aggregation, the Ag powder is used as a coating process by an organic material.

Then, the total weight was 1,700 g in the following composition ratio.

Weighing composition (mole fraction): 24Fe-24Pt-5Ag-40C-7SiO ₂

Next, in a Ar environment, the weighed powder was sealed with a zirconia grinding ball of a pulverizing medium in a ball pulverizer having a capacity of 10 liters, and mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

The cross section of the sintered body obtained in the above manner was ground and observed by an electron probe microanalyzer (EPMA) to confirm the Fe-Pt alloy phase, the Ag phase, the C phase, and the oxide phase (SiO _{2 ).} ) an organization structure that is evenly dispersed from each other. Further, as a result of observing the range of 0.2 mm ² by EPMA, it was confirmed that all the imaginary circles having a radius of 10 μm formed around an arbitrary point in the Ag phase were contained in an area ratio of 80% or more of the Ag phase. Or having a shape having a tangent point or an intersection point of at least 2 points or more between the imaginary circle and the outer edge of the Ag phase. Further, the area ratio of the C phase to the oxide phase was determined from the image in the range of 1 mm ² observed by an optical microscope, and was 47.4%. This value is outside the scope of the request in this case.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, Ag and Si are measured using an ICP-AES device, C is measured by a carbon analyzer using a high-frequency induction heating furnace-infrared absorption method, and O is an oxygen analyzer using an inert gas melting-infrared absorption method. measuring. As a result of calculating the atomic ratio from the weight ratio obtained in this manner, the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and as a result, it was 7.9.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. This target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Annehua), and sputtering was performed under the same conditions as in Example 1. As a result, the number of particles was 716, and the number of particles was significantly increased as compared with Example 1.

(Example 3)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, Cu powder having an average particle diameter of 3 μm, Co powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 10 μm (graphite) Powder) as a raw material powder. In order to prevent aggregation, the Ag powder is used as a coating process by an organic material.

Then, the total weight was 2,200 g in the following composition ratio.

Weighing composition (mole fraction): 26Fe-26Pt-6Cu-5Co-7Ag-30C

Next, in a Ar environment, the weighed powder was sealed with a zirconia grinding ball of a pulverizing medium in a ball pulverizer having a capacity of 10 liters, and mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

A part of the sintered body obtained in the above manner was cut out, and the cut surface thereof was ground and observed with an electron probe microanalyzer (EPMA). As a result, the structure in which the Fe-Pt-Cu-Co alloy phase, the Ag phase, and the C phase were uniformly dispersed was confirmed. Further, as a result of observing the range of 0.2 mm ² , it was confirmed that all of the imaginary circles having a radius of 10 μm formed around an arbitrary point in the Ag phase were 80% or more in terms of the area ratio, or There is a shape in which a point or intersection of at least 2 points or more is provided between the imaginary circle and the outer edge of the Ag phase. Further, the C-phase area ratio was determined from an image in the range of 1 mm ² observed by an optical microscope, and was 21.6%.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, Ag, Cu, and Co are measured using an ICP-AES apparatus, and C is measured by a carbon analyzer using a high-frequency induction heating furnace-infrared absorption method. The atomic ratio was calculated from the weight ratio obtained in this manner, and the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and the result was 4.2.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. This target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Annehua), and sputtering was performed under the same conditions as in Example 1. As a result, the number of particles was 17.

(Comparative Example 6)

Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 2 μm, Cu powder having an average particle diameter of 3 μm, Co powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 10 μm (graphite) Powder) as a raw material powder. Ag powder is used without treatment to prevent condensation.

Then, the total weight was 2,200 g in the following composition ratio.

Weighing composition (mole fraction): 26Fe-26Pt-6Cu-5Co-7Ag-30C

Next, in the Ar environment, weigh the powder and the zirconia mill of the pulverizing medium. The balls were closed together in a ball mill having a capacity of 10 liters, and were mixed and pulverized by rotating for 4 hours. Then, the powder taken out from the pot was filled in a carbon mold, and it was molded and sintered using a hot press apparatus. The conditions of the hot pressing were a vacuum atmosphere, a temperature increase rate of 300 ° C / hour, a holding temperature of 900 ° C, and a holding time of 2 hours, and the pressure was applied at 30 MPa from the start of the temperature rise to the end of the holding. After the end of the stay, it is naturally cooled directly in the chamber.

A part of the sintered body obtained in the above manner was cut out, and the cross section was ground and observed by an electron probe microanalyzer (EPMA) to confirm the Fe-Pt-Cu-Co alloy phase, the Ag phase, and the C phase. An organizational structure that is evenly dispersed from each other. Further, as a result of observing a region of 0.2 mm ² by EPMA, a coarse Ag phase was observed, and it was confirmed that the Ag phase was contained in all imaginary circles having a radius of 10 μm centered at any point in the phase, or Ag phase. A shape having a "cut point or intersection point of at least two points between the imaginary circle and the outer edge of the Ag phase" is not provided, and accounts for 20% or more of the Ag phase in terms of area ratio. The reason for this is considered to be that Ag powder is used without being treated to prevent aggregation. Further, the C-phase area ratio was determined from an image in the range of 1 mm ² observed by an optical microscope, and was 21.7%.

Further, composition analysis was carried out using a small piece collected from a sintered body. Fe, Pt, and Ag were measured using an ICP-AES apparatus, and C was measured by a carbon analyzer using a high-frequency induction heating furnace-infrared absorption method. The atomic ratio was calculated from the weight ratio obtained in this manner, and the ratio of the number of C atoms was divided by the ratio of the number of Ag atoms, and the result was 4.2.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm on a lathe to obtain a disk-shaped target. This target was mounted on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Annehua), and sputtering was performed under the same conditions as in Example 1. As a result, the number of particles was 183, and the number of particles was increased as compared with Example 3.

As described above, it is known that in any of the embodiments, the amount of particles generated at the time of sputtering can be reduced, and it is very important to increase the yield at the time of film formation.

Further, in the examples, although Cu and Co are contained as targets for addition metals, other metal elements (Au, B, Cr, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, Ru, In the case of Sn, Ta, W, V, Zn), the same result can be obtained.

Industrial availability

The sputtering target of the present invention has an excellent effect of reducing the amount of particles generated at the time of sputtering and improving the yield at the time of film formation. Therefore, it is suitable as a sputtering target for forming a magnetic thin film of a granular structure type.

Claims (4)

A sputtering target comprising an Fe-Pt-based alloy phase, an Ag phase, and a C phase, wherein a value obtained by dividing a C atom number ratio by an Ag atom number ratio in a composition of a sputtering target as a whole is 4 In the above-described 10 or less, in the cross section of the sputtering target, the Ag phase is included in all imaginary circles having a radius of 10 μm drawn around any point in the Ag phase, or the Ag phase has a shape in which the imaginary circle and There are at least two or more tangent points or intersections between the outer edges of the Ag phases, and the area ratio of the C phases in the cross section is 10% or more and 45% or less. A sputtering target is composed of an Fe-Pt-based alloy phase, an Ag phase, a C-phase, and an oxide phase, and is characterized in that a ratio of a C atom number is divided by an Ag atom number ratio in a composition of a sputtering target as a whole. The value is 4 or more and 10 or less. In the cross section of the sputtering target, the Ag phase is included in all imaginary circles having a radius of 10 μm centered on an arbitrary point in the Ag phase, or the Ag phase has the following shape: The imaginary circle has a tangent point or an intersection point of at least two points or more between the outer edge of the Ag phase, and the area ratio of the C phase to the oxide phase in the cross section is 10% or more and 45% or less in total. The sputtering target of claim 2, wherein the oxide phase is selected from the group consisting of Al, B, Ba, Be, Bi, Ca, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe. , Ga, Gd, Ge, Hf, Ho, La, Li, Lu, Mg, Mo, Nb, Nd, Ni, Pr, Sb, Sc, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tm One or more elements of V, W, Y, Yb, Zn, and Zr are oxides of constituent components. The sputtering target according to any one of claims 1 to 3, which is selected from the group consisting of Au, B, Co, Cr, Cu, Ga, Ge, Mn, Mo, Nb, Ni, Pd, Re, Rh, One or more elements of Ru, Sn, Ta, W, V, and Zn are used as the metal component, and the content thereof is 0.5% or more and 15% or less in terms of the ratio of the number of atoms in the metal component.