Manganese sputtering target, production method thereof, manganese think film, and production method thereof

Abstract

To provide a method for producing a manganese sputtering target having high purity and high sintering density without adding a sintering assistant to a manganese powder raw material or with an extremely low range of an addition amount of the sintering assistant by pulverizing the manganese powder raw material in a proper grain size range without fine-pulverizing the manganese powder raw material, a high purity manganese sputtering target, a manganese thin film obtained from the high purity manganese sputtering target, and a production method thereof.SOLUTION: A manganese sputtering target production method includes: a step 1 of obtaining manganese powder with a grain size range of 15 μm or more and 35 μm or less by pulverizing a manganese powder raw material; and a step 2 of obtaining a sintered body with sintering density of 95% or more and 99% or less and metal impurity density of less than 100 ppm by heating and solidifying the manganese powder at 600°C or more and 1200°C or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a manganese sputtering target and a method for producing the same, and a manganese thin film and a method for producing the same. [Background technology]

[0002] Manganese is widely used in technical fields such as magnetic materials and semiconductors. For example, in the field of magnetic materials, a sputtering target is used to form a magnetic thin film, which is used in magnetic devices, magnetic sensors, recording media, etc. In the field of semiconductors, ferromagnetic semiconductor field-effect transistors (FETs) and magnetic semiconductors that utilize the ferromagnetism of manganese are known.

[0003] The purity of manganese has a significant impact on the quality and performance of thin films, so it is necessary to use manganese with as high a purity as possible. However, crude manganese contains gas components (oxygen, carbon, nitrogen, hydrogen, etc.). For this reason, technologies for recovering high-purity manganese that reduce the gas components have been developed.

[0004] Patent Documents 1 to 5 report techniques for producing high-purity manganese in which the total content of gas components is reduced to less than 100 ppm by irradiating crude manganese with an electron beam, taking advantage of the extremely high vapor pressure of manganese, thereby evaporating and condensing the gas components contained in the crude manganese.

[0005] Also reported is a method for producing high-purity manganese by pre-melting crude manganese at 1250 to 1500°C and then vacuum distilling it at 1100 to 1500°C (Patent Document 6).

[0006] Sputtering targets made from high-purity manganese obtained according to Patent Documents 1 to 6 can suppress splashes, abnormal discharges, or particle generation during sputtering caused by gas components.

[0007] For sputtering targets, it is preferable to use high-purity manganese or the like, since this allows for the formation of uniform thin films at a high deposition rate. Sputtering targets obtained from high-purity manganese or the like have a highly densified structure. Such a structure can be obtained by molding high-purity manganese or the like, selecting a load, sintering temperature, and sintering time, and then sintering at a high temperature for a long period of time.

[0008] However, the maximum load during sintering is determined by the specifications of the sintering machine, making it difficult to adjust. Also, the sintering temperature must be lower than the melting point of the sintering material, such as high-purity manganese, and cannot be set to an unlimitedly high temperature.

[0009] On the other hand, if the sintering time is long, the time required for one sintering process will increase, which will reduce the productivity of the sputtering target. Also, if the sintering time is long, the refractory material in the sintering equipment will be worn out. Therefore, it is necessary to keep the sintering time as short as possible in the manufacturing process.

[0010] While there are limitations on the adjustment of load, temperature, and time during sintering, it is possible to increase the sintered density of sputtering targets by modifying the raw material sintered powder. Increasing the sintered density allows for the formation of uniform thin films at high deposition rates.

[0011] There are two main known methods for modifying sintered powder. One is to reduce the particle size of the sintered powder, and the other is to add a sintering aid. Both of these methods improve the sinterability of the sintered powder. When the particle size of the sintered powder is small, the sintered powder particles bond well together during sintering, improving sinterability. On the other hand, when a sintering aid is added, a low-melting-point alloy or compound is formed between the sintering raw material powder (the matrix raw material) and the sintering aid, improving sinterability. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-371325 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-80150 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-220444 [Patent Document 4] Japanese Patent Application Laid-Open No. 2012-72498 [Patent Document 5] Japanese Patent Application Laid-Open No. 2009-1913 [Patent Document 6] Japanese Patent Application Laid-Open No. 2007-186793 Summary of the Invention [Problem to be solved by the invention]

[0013] However, the above two methods are not effective when producing a sputtering target of high purity manganese with a reduced gas content.

[0014] When reducing the particle size of the sintered powder, if the raw material coarse manganese powder is finely ground over a long period of time, it is inevitable that metals will be mixed into the coarse manganese powder due to wear of the grinding equipment, etc., and furthermore, when the particles are finely ground, there is a problem that the oxygen concentration in the sintered powder and even the sputtering target increases.

[0015] On the other hand, when a sintering aid is added to the coarse manganese powder, the sintering aid acts as an impurity in the manganese matrix, making it difficult to produce a high-purity manganese sputtering target.

[0016] Against this background, the present invention aims to provide a method for producing a manganese sputtering target having high purity and high sintered density, without adding a sintering aid to the manganese powder raw material, or by adding an extremely small amount of sintering aid, by finely pulverizing the manganese powder raw material to a particle size within an appropriate range before sintering; a high-purity manganese sputtering target; and a manganese thin film obtained from the high-purity manganese sputtering target and a method for producing the same. [Means for solving the problem]

[0017] The present invention comprises the following items. The manganese sputtering target of the present invention has a sintered density of 95% or more and 99% or less, and a metal impurity concentration of less than 100 ppm.

[0018] The manganese sputtering target preferably has a sintered density of 95% or more and 99% or less, a metal impurity concentration of less than 100 ppm, and an oxygen concentration of 2000 ppm or less.

[0019] The method for producing a manganese sputtering target of the present invention includes step 1 of pulverizing a manganese powder raw material to obtain manganese powder having a particle size of 15 μm or more and 35 μm or less, and step 2 of heating and solidifying the manganese powder at 600°C or more and 1200°C or less to obtain a sintered body having a sintered density of 95% or more and 99% or less and a metal impurity concentration of less than 100 ppm.

[0020] The manganese sputtering target of the present invention contains 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese, has a sintered density of 95% to 99%, and has a metal impurity concentration of less than 100 ppm.

[0021] The manganese sputtering target preferably contains 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese, has a sintered density of 95% to 99%, a metal impurity concentration of less than 100 ppm, and an oxygen concentration of 2000 ppm or less.

[0022] The method for producing a manganese sputtering target of the present invention includes step 1-2 of pulverizing a mixed powder obtained by adding 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese to a manganese powder raw material to obtain manganese powder having a particle size of more than 35 μm and not more than 200 μm, and step 2-2 of heating the manganese powder at 600°C to 1200°C to solidify it, thereby obtaining a sintered body having a sintered density of 95% to 99% and a metal impurity concentration of less than 100 ppm.

[0023] The sintered body preferably has a sintered density of 95 to 99%, a metal impurity concentration of less than 100 ppm, and an oxygen concentration of 2000 ppm or less.

[0024] The manganese thin film of the present invention is obtained by using the manganese sputtering target.

[0025] The method for producing a manganese thin film of the present invention comprises forming a thin film on a substrate by sputtering using the manganese sputtering target. [Effects of the Invention]

[0026] According to the present invention, for example, by pulverizing a manganese powder raw material having a particle size of 100 μm or more and 500 μm or less to make the particle size of the manganese powder before sintering 15 μm or more and 35 μm or less, it is possible to produce a manganese sputtering target with high purity and high sintered density in which metal impurities and oxygen concentrations are reduced without adding a sintering aid to the manganese powder raw material.

[0027] Furthermore, according to the present invention, for example, by pulverizing a manganese powder raw material having a particle size of 100 μm or more and 500 μm or less to make the particle size of the manganese powder before sintering greater than 35 μm and less than 200 μm, the amount of sintering aid mixed into the manganese powder raw material can be kept within an extremely low range, making it possible to produce a manganese sputtering target that has high purity and a high sintered density, with reduced metal impurities and oxygen concentrations. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a dot graph in which the concentration of metal impurities (ppm) in a sputtering target is plotted against the particle size (μm) of manganese powder. [Figure 2] 1 is a dot graph in which the oxygen concentration (ppm) in a sputtering target is plotted against the particle size (μm) of manganese powder. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described in detail below.

[0030] <Manganese sputtering target> The sputtering target of the present invention is made of high-purity manganese having a sintered density of 95% to 99% and a metal impurity concentration of less than 100 ppm. Hereinafter, a sintered body of such high-purity manganese powder will also be simply referred to as "high-purity manganese."

[0031] Furthermore, when the sputtering target of the present invention contains a metal or alloy with a melting point lower than that of manganese, it is made of high-purity manganese containing the metal or alloy in an amount of 20 ppm or more and 70 ppm or less, having a sintered density of 95% or more and 99% or less, and having a metal impurity concentration of less than 100 ppm.

[0032] The metal or alloy having a melting point lower than that of manganese serves as a sintering aid when obtaining a sintered body that is a sputtering target.

[0033] The manganese sputtering target of the present invention has a metal impurity concentration of less than 100 ppm, and therefore the purity of the high-purity manganese is 99.99% (4N) or higher, and preferably 99.995% or higher.

[0034] The metal impurities contained in the manganese sputtering target of the present invention are metals contained in the pyrolusite, which is a crude material, and are unavoidably contained metals. Examples of unavoidable metals include magnesium and vanadium.

[0035] The metal impurity concentration can be obtained by adding nitric acid and phosphoric acid to powder obtained by pulverizing the manganese sputtering target (high-purity manganese sintered body) of the present invention, decomposing the powder by heating, and measuring the concentration by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0036] The concentration of metal impurities contained in the manganese sputtering target of the present invention is less than 100 ppm, and from the viewpoint of forming a high-purity manganese thin film, the concentration of metal impurities is preferably 50 ppm or less.

[0037] When the manganese sputtering target of the present invention contains a metal or alloy having a melting point lower than that of manganese, the metal impurities contained in the manganese sputtering target, including these metals or alloys, are less than 100 ppm, preferably 50 ppm or less.

[0038] Examples of metals or alloys having a melting point lower than that of manganese that can be used in the manganese sputtering target of the present invention include aluminum (Al), zinc (Zn), antimony (Sb), tellurium (Te), aluminum-zinc alloys (Al-Zn), etc. Among these, aluminum (Al) and antimony (Sb) are preferred because they have a low vapor pressure during heating for sintering and are less likely to vaporize and disappear.

[0039] When the manganese sputtering target of the present invention contains a metal or alloy having a melting point lower than that of manganese, the content of the metal or alloy having a melting point lower than that of manganese is 20 ppm or more and 70 ppm or less. The content of the metal or alloy having a melting point lower than that of manganese may be 25 ppm or more, 30 ppm or more, or 32 ppm or more, and may be 65 ppm or less, 60 ppm or less, 57 ppm or less, or 53 ppm or less.

[0040] Manganese is silvery white, but when exposed to air, a dense oxide film forms on its surface. This means that manganese has a high affinity for oxygen, and the oxygen concentration tends to be high. Therefore, a small amount of oxygen remains in the manganese sputtering target (in the high-purity manganese sintered body). However, to obtain a high-purity manganese thin film, a low oxygen concentration in the sputtering target is required.

[0041] In a preferred embodiment of the manganese sputtering target (high purity manganese) of the present invention, the concentration of metal impurities such as magnesium and vanadium is preferably less than 100 ppm, and the oxygen concentration is preferably 2000 ppm or less.

[0042] The oxygen concentration in the sputtering target is more preferably 1000 ppm or less. The oxygen concentration in the sputtering target can be reduced by adjusting the grinding conditions of the manganese powder raw material and the amount of oxygen in the firing atmosphere.

[0043] The oxygen concentration in a sputtering target is measured by the inert gas fusion-infrared absorption method. Specifically, a crushed sputtering target sample is placed in a crucible and melted by electric heat, gasifying the elements in the sample. The sample gas is then transported to an infrared detector using helium (He), an inert gas, as a carrier gas, and the oxygen concentration in the sample gas is measured.

[0044] The dot graph in Figure 2 is a graph plotting the oxygen concentration (ppm) in the sputtering target against the particle size (μm) of the manganese powder, and shows that when the particle size of the manganese powder is approximately 15 μm or more and 35 μm or less, the oxygen concentration in the sputtering target is 2000 ppm or less.

[0045] When the manganese sputtering target of the present invention contains a metal or alloy with a melting point lower than that of manganese, the oxygen concentration in the sputtering target becomes 2000 ppm or less when the particle size of the manganese powder is approximately 35 μm to 200 μm.

[0046] Table 1 shows the experimental results that show that when the particle size of the manganese powder is approximately 35 to 200 μm, the oxygen concentration in the sputtering target is 2000 ppm or less.

[0047] [Table 1]

[0048] The shape of the sputtering target is not particularly limited, and a flat (circular or rectangular) or cylindrical (rotary) shape can be selected depending on the type and purpose of the sputtering device. The size of the target is also not particularly limited, and can be selected from a range of approximately 1 inch to 440 mm. In a preferred embodiment of the present invention, the sputtering target is a circle with a diameter of 25.4 to 300 mm.

[0049] The sintered density of the manganese sputtering target of the present invention, according to JIS Z 2501:2000 (Sintered metal materials - Testing method for density, oil content and open porosity), is 95% or more and 99% or less, preferably 98% or more and 99% or less.

[0050] Most sputtering targets manufactured by the sintering method and used industrially have a sintered density of 90 to 99%, but when manufactured by a melting method, such as the sputtering targets described in Patent Documents 1 to 6, the sintered density is always 100%.

[0051] <Manufacturing method of manganese sputtering target> The method for producing a manganese sputtering target of the present invention includes step 1 of pulverizing a manganese powder raw material with a particle size of, for example, 100 μm or more and 500 μm or less to obtain manganese powder with a particle size in the range of 15 μm or more and 35 μm or less, and step 2 of heating and solidifying the manganese powder at 600°C or more and 1200°C or less to obtain a sintered body with a sintered density of 95% or more and 99% or less and a metal impurity concentration of less than 100 ppm.

[0052] Furthermore, when the sputtering target of the present invention contains a metal or alloy having a melting point lower than that of manganese, the method for producing a high-purity manganese sputtering target of the present invention includes step 1-2 of pulverizing a mixed powder obtained by adding 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese to a manganese powder raw material to obtain a manganese powder with a particle size in the range of 35 μm to 200 μm, and step 2-2 of heating and solidifying the manganese powder at 600°C to 1200°C to obtain a sintered body with a sintered density of 95% to 99% and a metal impurity concentration of less than 100 ppm.

[0053] Specific examples of the manganese powder raw material used in the present invention include electrolytic manganese powder, electric furnace milled manganese powder, and thermite-produced manganese powder. All of these are ground materials obtained by coarsely pulverizing the raw material solid or aggregate, usually to a particle size of 100 μm to 500 μm, preferably 200 μm to 400 μm. The manganese powder raw material used in the present invention may also be obtained by coarsely pulverizing pyrolusite using a stamp mill or the like to obtain a powder raw material in the range of 100 μm to 500 μm.

[0054] [Without sintering aids] In step 1, the manganese powder raw material is mechanically pulverized using a ball mill or the like to prepare manganese powder with a particle size ranging from 15 μm to 35 μm, preferably from 20 μm to 30 μm.

[0055] When the particle size of the manganese powder is less than 15 μm, the metal impurity concentration and oxygen concentration tend to increase, as shown in the dot graph in Figure 1, which plots the metal impurity concentration (ppm) in the sputtering target against the particle size (μm) of the manganese powder.

[0056] On the other hand, if the particle size exceeds 35 μm, it becomes difficult to increase the sintered density, and it may be impossible to obtain a sputtering target with a sintered density of 95% to 99%. Also, if the particle size exceeds 35 μm, in order to increase the sintered density, it is necessary to increase the heating temperature to near the melting point of manganese or to increase the sintering pressure, making it difficult to stably produce a sputtering target.

[0057] By setting the particle size of the manganese powder before sintering to the range of 15 μm or more and 35 μm or less, it is possible to prevent oxygen from being mixed into the manganese powder during sintering, and to obtain a sputtering target with a reduced oxygen concentration.

[0058] In the present invention, particle size (μm) refers to the median size according to JIS Z 8825:2020 (particle size-laser diffraction / scattering method). The particle size in the present invention can be measured using Partica LA-960V2 manufactured by Horiba, Ltd.

[0059] The dot graph in Figure 1, which plots the metal impurity concentration (ppm) in a sputtering target against the particle size (μm) of the manganese powder, shows that when manganese powder with a particle size of 15 to 35 μm is used, the metal impurity concentration in the produced sputtering target will be less than 100 ppm.

[0060] The process suitable for pulverizing the manganese powder raw material is not particularly limited, but for example, pulverization using a ball mill can be mentioned. When pulverization is performed using a ball mill, fine powder having a desired particle size can be obtained by adjusting the rotation speed and processing time.

[0061] In the present invention, the particle size of the resulting fine powder can be adjusted to fall within the above range by setting the rotation speed to 30 to 180 rpm, preferably 50 to 100 rpm, and the treatment time to 6 to 18 hours, preferably 8 to 15 hours.

[0062] Step 2 is a sintering process in which the manganese powder having a particle size of 15 μm or more and 35 μm or less obtained in Step 1 is heated at 600°C or more and 1200°C or less to solidify the manganese powder, thereby obtaining a sintered body (high-purity manganese) with a sintered density of 95% or more and 99% or less and a metal impurity concentration of less than 100 ppm.

[0063] The atmosphere during heating can be selected from air, an inert atmosphere, a reducing atmosphere, a low-oxygen atmosphere, or the like, depending on the quality and performance of the manganese sputtering target (high-purity manganese) to be produced.

[0064] Furthermore, considering that manganese has a melting point of 1246°C and is highly brittle and has low ductility, the heating temperature is set to 600°C or higher and 1200°C or lower, and preferably 700°C or higher and 800°C or lower. The heat treatment in step 2 is carried out under a reduced pressure of 0.2 to 5 Pa, and preferably 0.4 to 0.9 Pa.

[0065] [When sintering aids are included] When the sputtering target of the present invention contains a metal or alloy having a melting point lower than that of manganese, in step 1-2, a mixed powder obtained by adding 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese to a manganese-based powder raw material is subjected to a mechanical pulverization treatment using a ball mill or the like to adjust the particle size to a manganese-based powder having a particle size in the range of 35 μm to 200 μm, preferably 50 μm to 150 μm.

[0066] As described above, if the particle size of the manganese powder is 35 μm or less, a sintered body (manganese sputtering target) with a sintered density of 95% or more and 96% or less can be obtained without adding a metal or alloy with a melting point lower than that of manganese as a sintering aid.

[0067] On the other hand, if the particle size exceeds 200 μm, it becomes difficult to increase the density of the sintered body, and even if a small amount of a metal or alloy with a melting point lower than that of manganese is added as a sintering aid, it becomes impossible to obtain a sputtering target with a sintered density of 95% to 99%. Furthermore, if the particle size exceeds 200 μm, in order to increase the sintered density, it is necessary to increase the heating temperature to near the melting point of manganese or to increase the sintering pressure, making it difficult to stably produce a sputtering target.

[0068] By setting the particle size of the manganese powder before sintering to a range of more than 35 μm and not more than 200 μm, it is possible to prevent oxygen from being mixed into the manganese powder during sintering, and to obtain a sputtering target with a reduced oxygen concentration.

[0069] The process suitable for pulverizing the manganese powder raw material is not particularly limited, but for example, pulverization using a ball mill can be mentioned. When pulverization is performed using a ball mill, fine powder having a desired particle size can be obtained by adjusting the rotation speed and processing time.

[0070] In the present invention, the particle size of the resulting fine powder can be adjusted to fall within the above range by setting the rotation speed to 30 to 180 rpm, preferably 50 to 100 rpm, and the treatment time to 6 to 18 hours, preferably 8 to 15 hours.

[0071] Step 2-2 is a sintering process. In step 2, the manganese powder with a particle size of more than 35 μm and not more than 200 μm obtained in step 1 is heated at 600°C to 1200°C to solidify the manganese powder, thereby obtaining a sintered body (high-purity manganese) with a sintered density of 95% to 99% and a metal impurity concentration of less than 100 ppm.

[0072] The atmosphere during heating can be selected from air, an inert atmosphere, a reducing atmosphere, a low-oxygen atmosphere, or the like, depending on the quality and performance of the manganese sputtering target (high-purity manganese) to be produced.

[0073] Furthermore, considering that manganese has a melting point of 1246°C and is highly brittle and has low ductility, the heating temperature is set to 600°C or higher and 1200°C or lower, and preferably 700°C or higher and 800°C or lower. The heat treatment in step 2 is carried out under a reduced pressure of 0.2 to 5 Pa, and preferably 0.4 to 0.9 Pa.

[0074] <Manganese thin film and its manufacturing method> The thin film made of high purity manganese of the present invention can be obtained by using the manganese sputtering target of the present invention.

[0075] The method for producing a manganese thin film of the present invention is a method for forming a thin film on a substrate by sputtering using the manganese sputtering target of the present invention.

[0076] The sputtering method is preferable to the thermal spraying method in that it allows deposition at a low temperature and does not form defects or voids on the surface of the thin film.

[0077] The manganese sputtering target of the present invention is conductive and can be used in any of direct current sputtering (DC sputtering), radio frequency sputtering (RF sputtering), and alternating current sputtering (AC sputtering). According to the sputtering method, reactive sputtering is performed by introducing oxygen, nitrogen, or the like into the chamber, thereby forming a film of manganese oxide or nitride.

[0078] When the manganese sputtering target of the present invention is used in, for example, a DC sputtering method, the sputtering target is supplied with a gas pressure of 0.2 to 5 Pa and an electric current of 2 to 20 W / cm. 2In a preferred embodiment, a thin film is formed on the substrate by supplying a DC power of 5 to 12 W / cm at a gas pressure of 0.2 to 5 Pa. 2 This allows for efficient formation of a thin film.

[0079] The substrate on which the manganese thin film of the present invention is formed is not particularly limited. It can be appropriately selected depending on the application of the manganese thin film. Examples of the substrate on which the manganese thin film of the present invention is formed include a silicon wafer, a sapphire substrate, and a magnesia substrate.

[0080] <Manganese sputtering target applications> The sputtering target made of high-purity manganese of the present invention is suitable for use in magnetic devices such as spin valve transistors and magnetic tunnel junctions; magnetic sensors such as magnetic sensors, magnetic heads, and magnetic field measuring instruments; industrial coatings such as optical thin film coatings; and in the fields of semiconductors and photovoltaic power generation. [Example]

[0081] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0082] <Various measurement methods> In the examples and comparative examples, various measurements were carried out by the following methods.

[0083] (1) Particle size The median diameter was measured according to JIS Z 8825:2020 (particle size - laser diffraction and scattering method) using a Partica LA-960V2 manufactured by Horiba Ltd.

[0084] (2) Sintered density Measurements were carried out in accordance with JIS Z 2501:2000 (Sintered metal materials - Test methods for density, oil content and open porosity).

[0085] (3) Metal impurity concentration The obtained manganese sputtering target was pulverized into powder, to which nitric acid and phosphoric acid were added, followed by thermal decomposition, and the powder was measured by ICP atomic emission spectroscopy (ICP-AES).

[0086] (4) Oxygen concentration Measurements were made using the inert gas fusion-infrared absorption method. Specifically, the resulting sputtering target was crushed into a sample and placed in a crucible, where it was melted by electric heat. The elements in the sample were gasified, and the sample gas was transported to an infrared detector using helium (He), an inert gas, as a carrier gas, and the oxygen concentration in the sample gas was measured.

[0087] [Example 1] (Manufacturing of manganese sputtering targets) The raw material pyrolusite was coarsely pulverized in a stamp mill to obtain a manganese powder raw material with a particle size of 100 to 500 μm. The obtained manganese powder raw material was pulverized in a ball mill at 60 rpm for 12 hours to obtain a manganese powder with a particle size of 19 μm.

[0088] The obtained manganese powder was placed in a hot press furnace, heated to 800°C, below the melting point of manganese, and solidified and molded to obtain a sputtering target with a diameter of 8 inches, a thickness of 6 mm, and a sintered density of 98.6%.

[0089] (Manganese thin film preparation) Using the obtained sputtering target, a silicon wafer substrate was sputtered in a sputtering device at a gas pressure of 0.2 to 5 Pa with an output of 8 W / cm. 2 DC sputtering was carried out at 1000 kJ / min, and a thin film with a thickness of 10.3 nm was formed at a deposition rate of 7.9 nm / min. No abnormalities such as arcing were observed during deposition.

[0090] (Measurement evaluation) The metal impurity concentration of the sputtering target was 50 ppm, and the oxygen concentration was 1800 ppm, and both the metal impurity concentration and the oxygen concentration were reduced.

[0091] [Example 2] (Manufacturing of manganese sputtering targets) The raw material pyrolusite was coarsely pulverized in a stamp mill to obtain a manganese powder raw material with a particle size of 100 to 500 μm. The obtained manganese powder raw material was pulverized in a ball mill at 60 rpm for 12 hours to obtain a manganese powder with a particle size of 24 μm.

[0092] The obtained manganese powder was placed in a hot press furnace and heated to 740°C, which is below the melting point of manganese, and solidified and molded to obtain a sputtering target with a diameter of 6 inches, a thickness of 5 mm, and a sintered density of 96.9%.

[0093] (Manganese thin film preparation) Using the obtained sputtering target, a silicon wafer substrate was sputtered in a sputtering device at a gas pressure of 0.2 to 5 Pa with an output of 6 W / cm. 2 DC sputtering was performed at 4.7 nm / min to form a thin film with a thickness of 9.8 nm. No abnormalities such as arcing were observed during film formation.

[0094] (Measurement evaluation) The metal impurity concentration of the sputtering target was 90 ppm, and the oxygen concentration was 1400 ppm, indicating that both the metal impurity concentration and the oxygen concentration were reduced.

[0095] [Comparative Example 1] (Manufacturing of manganese sputtering targets) The raw material, pyrolusite, was coarsely pulverized in a stamp mill to obtain a manganese powder raw material with a particle size of 100 to 500 μm. The obtained manganese powder raw material was then pulverized in a ball mill at 60 rpm for 4 hours to obtain manganese powder with a particle size of 52 μm.

[0096] The obtained manganese powder was placed in a hot press furnace, heated to 740°C, below the melting point of manganese, and solidified and molded to produce a sputtering target with a diameter of 6 inches and a thickness of 5 mm. However, the sintered density was only 89.8%, and a sintered density of 95% or more could not be achieved.

[0097] (Manganese thin film preparation) Using this sputtering target, a silicon wafer substrate was sputtered in a sputtering apparatus at a gas pressure of 0.2 to 5 Pa with an output of 6 W / cm. 2 DC sputtering was performed at 4.4 nm / min to form a thin film with a thickness of 9.1 nm. No abnormalities such as arcing were observed during film formation.

[0098] (Measurement evaluation) The metal impurity concentration of the sputtering target was 100 ppm, and the oxygen concentration was 1700 ppm.

[0099] Comparative Example 2 (Manufacturing of manganese sputtering targets) The raw material, pyrolusite, was coarsely pulverized in a stamp mill to obtain a manganese powder raw material with a particle size of 100 to 500 μm. The obtained manganese powder raw material was then pulverized in a ball mill at 60 rpm for 24 hours to obtain manganese powder with a particle size of 9.6 μm.

[0100] The obtained manganese powder was placed in a hot press furnace, heated to 800°C, below the melting point of manganese, and solidified and molded to obtain a sputtering target with a diameter of 6 inches, a thickness of 5 mm, and a sintered density of 97.3%.

[0101] (Manganese thin film preparation) Using the obtained sputtering target, a silicon wafer substrate was sputtered in a sputtering device at a gas pressure of 0.2 to 5 Pa with an output of 6 W / cm. 2 DC sputtering was performed at 4.8 nm / min to form a thin film with a thickness of 9.8 nm. No abnormalities such as arcing were observed during film formation.

[0102] (Measurement evaluation) The metal impurity concentration of the sputtering target was 200 ppm, and the oxygen concentration was 2700 ppm.

[0103] [Example 3] (Manufacturing of manganese sputtering targets) The manganese powder raw material was obtained by coarsely pulverizing the raw material pyrolusite in a stamp mill to obtain a manganese powder raw material with a particle size of 100 to 500 μm. 38 ppm of Al was added to this manganese powder raw material as a metal or alloy with a melting point lower than that of manganese to obtain a mixed powder. The resulting mixed powder was then pulverized in a ball mill at 60 rpm for 12 hours to obtain a manganese powder with a particle size of 45 μm.

[0104] The obtained manganese powder was placed in a hot press furnace, heated to 800°C, below the melting point of manganese, and solidified and molded to obtain a sputtering target with a diameter of 8 inches, a thickness of 6 mm, and a sintered density of 98.6%.

[0105] (Manganese thin film preparation) Using the obtained sputtering target, a silicon wafer substrate was sputtered in a sputtering device at a gas pressure of 0.2 to 5 Pa with an output of 8 W / cm. 2 DC sputtering was performed at 10.3 nm thick at a deposition rate of 7.9 nm / min. No abnormalities such as arcing were observed during deposition.

[0106] (Measurement evaluation) The metal impurity concentration of the sputtering target was 95 ppm, and the oxygen concentration was 1700 ppm, indicating that both the metal impurity concentration and the oxygen concentration were reduced.

[0107] [Example 4] (Manufacturing of manganese sputtering targets) The raw material, pyrolusite, was coarsely pulverized in a stamp mill to obtain a manganese powder raw material with a particle size of 100 to 500 μm. Zn, a metal or alloy with a melting point lower than that of manganese, was added at 57 ppm to obtain a mixed powder. The resulting mixed powder was then pulverized in a ball mill at 60 rpm for 12 hours to obtain a manganese powder with a particle size of 188 μm.

[0108] The obtained manganese powder was placed in a hot press furnace and heated to 740°C, which is below the melting point of manganese, and solidified and molded to obtain a sputtering target with a diameter of 6 inches, a thickness of 5 mm, and a sintered density of 96.9%.

[0109] (Manganese thin film preparation) Using the obtained sputtering target, a silicon wafer substrate was sputtered in a sputtering device at a gas pressure of 0.2 to 5 Pa with an output of 6 W / cm. 2 DC sputtering was performed at 4.7 nm / min, and a thin film with a thickness of 9.8 nm was formed. No abnormalities such as arcing were observed during film formation.

[0110] (Measurement evaluation) The metal impurity concentration of the sputtering target was 88 ppm, and the oxygen concentration was 1500 ppm, indicating that both the metal impurity concentration and the oxygen concentration were reduced.

[0111] Comparative Example 3 (Manufacturing of manganese sputtering targets) The raw material, pyrolusite, was coarsely pulverized in a stamp mill to obtain a manganese powder raw material with a particle size of 100 to 500 μm. 52 ppm of Al-Zn alloy, a metal or alloy with a melting point lower than that of manganese, was added to the manganese powder raw material. The resulting mixed powder was then pulverized in a ball mill at 60 rpm for 4 hours to obtain a manganese powder with a particle size of 260 μm.

[0112] The obtained manganese powder was placed in a hot press furnace, heated to 740°C, below the melting point of manganese, and solidified and molded to produce a sputtering target with a diameter of 6 inches and a thickness of 5 mm. However, the sintered density was only 93.6%, and a sintered density of 95% or more could not be achieved.

[0113] (Manganese thin film preparation) Using the obtained sputtering target, a silicon wafer substrate was sputtered in a sputtering device at a gas pressure of 0.2 to 5 Pa with an output of 6 W / cm. 2DC sputtering was performed at 4.4 nm / min, and a thin film with a thickness of 9.1 nm was formed. No abnormalities such as arcing were observed during film formation.

[0114] (Measurement evaluation) The metal impurity concentration of the sputtering target was 100 ppm, and the oxygen concentration was 1700 ppm.

[0115] Comparative Example 4 (Manufacturing of manganese sputtering targets) The manganese powder raw material was obtained by coarsely pulverizing the raw material pyrolusite in a stamp mill to obtain a particle size of 100 to 500 μm. 40 ppm of Sb was added as a metal or alloy with a melting point lower than that of manganese to obtain a mixed powder. The obtained mixed powder was then pulverized in a ball mill at 60 rpm for 24 hours to obtain a manganese powder with a particle size of 416 μm.

[0116] The obtained manganese powder was placed in a hot press furnace, heated to 800°C, below the melting point of manganese, and solidified and molded to obtain a sputtering target with a diameter of 6 inches, a thickness of 5 mm, and a sintered density of 89.5%.

[0117] (Manganese thin film preparation) Using the obtained sputtering target, a silicon wafer substrate was sputtered in a sputtering device at a gas pressure of 0.2 to 5 Pa with an output of 6 W / cm. 2 DC sputtering was performed at 4.8 nm / min to form a thin film with a thickness of 9.8 nm. No abnormalities such as arcing were observed during film formation.

[0118] (Measurement evaluation) The metal impurity concentration of the sputtering target was 200 ppm, and the oxygen concentration was 2700 ppm. [Industrial Applicability]

[0119] The manganese sputtering target of the present invention can be suitably used in technical fields such as magnetic devices (spin valve transistors, magnetic tunnel junctions, etc.), magnetic sensors (magnetic sensors, magnetic heads, magnetic field measuring instruments, etc.), recording media (magnetic disks, magnetic tapes, etc.), as well as semiconductors, photovoltaic power generation, industrial coatings (optical thin film coatings, etc.), and photovoltaic power generation.

Claims

1. A manganese sputtering target having a sintered density of 95% or more and 99% or less and a metal impurity concentration of less than 100 ppm.

2. 2. The manganese sputtering target according to claim 1, wherein the sintered density is 95% or more and 99% or less, the metal impurity concentration is less than 100 ppm, and the oxygen concentration is 2000 ppm or less.

3. a step 1 of pulverizing a manganese powder raw material to obtain manganese powder having a particle size in the range of 15 μm to 35 μm; and step 2 of heating the manganese powder at 600°C or higher and 1200°C or lower to solidify it, thereby obtaining a sintered body having a sintered density of 95% or higher and 99% or lower and a metal impurity concentration of less than 100 ppm.

4. A manganese sputtering target containing 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese, having a sintered density of 95% to 99%, and having a metal impurity concentration of less than 100 ppm.

5. 5. The manganese sputtering target according to claim 4, which contains 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese, has a sintered density of 95% to 99%, has a metal impurity concentration of less than 100 ppm, and has an oxygen concentration of 2000 ppm or less.

6. a step 1-2 of adding 20 ppm to 70 ppm of a metal or alloy having a melting point lower than that of manganese to a manganese powder raw material, and pulverizing the resulting mixed powder to obtain manganese powder having a particle size in the range of more than 35 μm and not more than 200 μm; and step 2-2 of heating the manganese powder at 600°C or higher and 1200°C or lower to solidify it, thereby obtaining a sintered body having a sintered density of 95% or higher and 99% or lower and a metal impurity concentration of less than 100 ppm.

7. 7. The method for producing a manganese sputtering target according to claim 3, wherein the sintered body has a sintered density of 95% or more and 99% or less, a metal impurity concentration of less than 100 ppm, and an oxygen concentration of 2000 ppm or less.

8. A manganese thin film obtained by using the manganese sputtering target according to claim 1 or 4.

9. A method for producing a manganese thin film, comprising forming a thin film on a substrate by sputtering using the manganese sputtering target according to claim 1 or 4.

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