Materials containing molybdenum

Abstract

This material containing molybdenum has a crystal grain size of 25 μm or greater, a density of 10.15 g / cm3 or greater, a molybdenum content of 99.95 mass% or greater, and a mass ratio (in-grain W / grain boundary W) of the in-grain tungsten content / grain boundary tungsten content of 0.8 or less.

Description

[Technical Field]

[0001] This disclosure relates to a material containing molybdenum. This application claims priority under Japanese Patent Application No. 2023-176718, filed on 12 October 2023. All contents contained in said Japanese Patent Application are incorporated herein by reference. [Background technology]

[0002] Conventionally, molybdenum plates have been disclosed in, for example, Japanese Patent Publication No. 2002-69628 (Patent Document 1), International Publication No. 2019-176962 (Patent Document 2), Japanese Patent Publication No. 2005-133198 (Patent Document 3), Japanese Patent Publication No. 2015-221937 (Patent Document 4), Japanese Patent Publication No. 2-24901 (Patent Document 5), and Japanese Patent Publication No. 2012-201930 (Patent Document 6). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-69628 [Patent Document 2] International Publication No. 2019-176962 [Patent Document 3] Japanese Patent Publication No. 2005-133198 [Patent Document 4] Japanese Patent Publication No. 2015-221937 [Patent Document 5] Special Publication No. 2-24901 [Patent Document 6] Japanese Patent Publication No. 2012-201930 [Overview of the project]

[0004] The molybdenum-containing material of this disclosure has a grain size of 25 μm or larger and a density of 10.15 g / cm³. 3In summary, the molybdenum content is 99.95% by mass or more, and the ratio of intragranular tungsten content to intergranular tungsten content (intragranular W / intergranular W) is 0.8 or less. [Brief explanation of the drawing]

[0005] [Figure 1] Figure 1 is a photograph showing an example of the microstructure of primary recrystallized grains in a molybdenum-containing material. [Figure 2] Figure 2 is a photograph showing an example of the microstructure of secondary recrystallized grains in a molybdenum-containing material. [Figure 3] Figure 3 shows a diagram of an apparatus for measuring the ease of deformation at high temperatures. [Modes for carrying out the invention]

[0006] [Issues this disclosure aims to address] High-quality molybdenum material was needed.

[0007] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described.

[0008] Patent Document 1 discloses a technique for suppressing particle generation by covering the sides and backing plate (BP) surface of a sputtering target with metal foil or plate.

[0009] Patent Document 2 specifies a material containing molybdenum with a molybdenum content of 99.999% or more, a relative density of 98% or more, an average particle size of 45 μm or less, and a radiation dose of 0.03 cph / cm². 2 It has been disclosed that particles can be reduced by the following:

[0010] Patent Document 3 discloses that particles can be reduced by using a material containing molybdenum with a molybdenum content of 99.99% or more and a relative density of 98% or more. Manufactured by HIP.

[0011] In Patent Document 4, it is disclosed that by making the aspect ratio of the crystal structure of a molybdenum-containing material 3 or more, the sputtering rate can be adjusted and a long-life target can be obtained.

[0012] In Patent Document 5, it is disclosed that the average particle size of a molybdenum-containing material is in the range of 15 to 150 mm, and the thickness direction of the crystal grains is 1 / 5 or more of the plate thickness.

[0013] In Patent Document 6, it is disclosed that there is a region where the peak intensities of X-ray diffraction measurements (110) and (220) are less than the peak intensity of (211) at a depth of 1 / 5 in the plate thickness direction from the surface of a molybdenum-containing material.

[0014] 1. (Description of the object) The present disclosure relates to a molybdenum-containing material in which the amount of grain boundary impurities, crystal grain size, density, and molybdenum content are controlled. It has been found that an effect can be obtained by setting the following characteristic values within a predetermined range. <Crystal grain size> The crystal grain size is 25 μm or more and less than 1 mm.

[0015] The preferred range is 45 μm or more and less than 1 mm as the primary recrystallized grain size. The preferred range is 1 mm or more as the secondary recrystallized grain size.

[0016] A more preferred range is 10 mm or more as the secondary recrystallized grain size. Within this range, W and K in the grains are reduced, and the number of particles generated can be made smaller. <Impurity content ratio: inside grain / grain boundary> The mass ratio of the tungsten content in the grain to the tungsten content in the grain boundary (W in grain / W in grain boundary) is 0.8 or less.

[0017] Preferably, in the case of primary recrystallization, the mass ratio of the potassium content in the grain to the potassium content in the grain boundary (K in grain / K in grain boundary) is 0.7 or less.

[0018] Preferably, in the case of secondary recrystallization, the ratio of intragranular W to grain boundary W is 0.7 or less. More preferably, in the case of secondary recrystallization, the intragranular K / grain boundary K is 0.6 or less. <density> The density is 10.15 g / cm³. 3 (Relative density is 99.5% or higher.)

[0019] The preferred range is 10.18 g / cm³. 3 (Relative density is 99.8% or higher.) Within this range, the influence of voids within the target on film formation is minimal. <Molybdenum content> The molybdenum content is 99.95% by mass or more.

[0020] The preferred range is 99.999% by mass or higher. Within this range, the amount of particles caused by impurities can be reduced. <Tungsten content> Preferably, the tungsten content is 200 ppm or less. More preferably, it is 90 ppm or less. Within this range, W segregated at grain boundaries does not adversely affect particle generation. <Potassium content> Preferably, the potassium content is 20 ppm or less. Preferably, it is 10 ppm or less. Within this range, potassium segregated at grain boundaries does not adversely affect particle generation.

[0021] As a result of these effects, the number of particles generated in thin films deposited using a sputtering target fabricated according to this disclosure is, for example, 35 particles / mm². 2 The results are as follows:

[0022] The thin film sheet resistance (300 nm thickness) of a thin film deposited using a sputtering target manufactured in accordance with this disclosure is 1.5 Ω / □ or less.

[0023] Preferably, it exhibits the following characteristics: Particle generation rate: 15 particles / mm2 below.

[0024] Thin film sheet resistance (thickness 300nm): 1.2Ω / □ or less. Regarding particle generation, by limiting the number of particles between 20 nm and 1 μm to 35 or less, a thin film of suitable quality for reflective mask blanks can be obtained.

[0025] Furthermore, during 1800°C heat treatment, secondary recrystallization occurs, resulting in the growth of crystal grains of 1 mm or larger, more preferably 10 mm or larger, and reducing grain boundaries. This further reduces the number of particles generated. In addition, the high-temperature deformation resistance of the plate is also improved.

[0026] 2. (Manufacturing method and examples) <Manufacturing of molybdenum sputtering targets> A molybdenum sputtering target is manufactured based on the following steps: Step 1: Molybdenum raw material powder, Step 2: CIP, Step 3: Sintering, Step 4: Hot rolling, Step 5: Heat treatment, Step 6: Cutting, Step 7: Cutting and polishing, and Step 8: Bonding.

[0027] Step 1: Molybdenum raw material powder The molybdenum powder used as the raw material had a molybdenum content of 99.95% by mass or higher, and a particle size of 1 to 10 μm, as measured by the FSSS method, was used as the starting material.

[0028] If the molybdenum content is less than 99.95% by mass, the molybdenum content in the sputtered thin film decreases, and defects caused by impurities also occur.

[0029] If the Fsss particle size is finer than 1 μm, the risk of powder ignition increases, and if it exceeds 10 μm, sintering by powder metallurgy becomes difficult.

[0030] At this time, in order to cause slight segregation of W and K to grain boundaries due to grain boundary migration from the sintering stage, it is advisable to use molybdenum powder with excellent sintering properties (for example, powder containing molybdenum with an average particle size of 0.1 μm or more and 10 μm or less by the Fsss method, a molybdenum content of 99.99 mass% or more, and a compressive deformation strength of 100 MPa or more and 200 MPa or less).

[0031] Process 2: CIP Fill the above molybdenum powder into a predetermined rubber container and perform pressure molding by isostatic pressing (CIP). The CIP pressure is 1 - 3 ton / cm 2 , preferably 2.0 t / cm 2 .

[0032] If the pressure is lower than this, it will cause sintering cracks due to insufficient press body strength, and a higher pressure is not industrially realistic.

[0033] Process 3: Sintering Sinter the press body obtained above in a hydrogen atmosphere at a sintering temperature of 1600 °C or more and 2300 °C or less, preferably 1800 °C, for 3 - 20 hours to obtain a molybdenum sintered body with a density of approximately 9.7 g / cm 3 .

[0034] At temperatures below 1600 °C, the density after sintering is not sufficient, and temperatures above 2300 °C are not industrially realistic.

[0035] At this time, when molybdenum powder with poor sintering properties is used, slight segregation of W and K to grain boundaries due to grain boundary migration is unlikely to occur from the sintering stage. However, even when molybdenum powder with poor sintering properties is used, by adjusting the sintering time, the same effect as when molybdenum powder with excellent sintering properties is used can be obtained. This is an effect that appears by advancing sintering, and the adjustment of sintering conditions can be done not only with time but also with the amount of hydrogen and temperature.

[0036] Process 4: Hot rolling The molybdenum sintered body obtained above was inserted into a hydrogen heating furnace at 1100-1400°C and then hot-rolled. When the material cooled, heating was repeated as needed, and rolling was repeated until the desired thickness was achieved. The density after hot rolling was 10.15-10.22 g / cm³. 3 This process yields a molybdenum plate with a fibrous structure that is extended in the direction of compression.

[0037] Step 5: Heat treatment The molybdenum sheet obtained above is heat-treated at a temperature of 950°C or higher for 0.5 to 10 hours. Recrystallization occurs due to the heat treatment, and a molybdenum sheet with an equiaxed grain structure is obtained.

[0038] Figure 1 is a photograph showing an example of the microstructure of primary recrystallized grains in a molybdenum-containing material. Figure 2 is a photograph showing an example of the microstructure of secondary recrystallized grains in a molybdenum-containing material. <Primary recrystallization> As shown in Figure 1, the primary recrystallization temperature of molybdenum sheets varies slightly depending on the manufacturing conditions, but is generally around 950°C to 1700°C. The fibrous structure stretched by hot rolling grows into equiaxed grains with a grain size of several tens to several hundred micrometers (or several millimeters depending on the manufacturing conditions and temperature).

[0039] <Secondary recrystallization> As shown in Figure 2, secondary recrystallization of molybdenum plates requires higher temperatures than primary recrystallization and generally occurs at temperatures above 1700°C. However, the ease of secondary recrystallization varies depending on the manufacturing conditions. Secondary recrystallization is a phenomenon in which one of the adjacent primary recrystallized grains engulfs the other grain and grows. Heating at a certain temperature (e.g., 1800°C or 2000°C) for a long period of time (e.g., 5 or 10 hours) accelerates grain growth, resulting in giant crystals of 10 mm or more. Generally, heat treatment at high temperatures such as 2000°C or higher induces secondary recrystallization in a shorter time, but considering energy costs and other factors, the criterion used was whether a grain size of 1 mm or more could be achieved at 1800°C for 5 hours, which is easier to implement industrially.

[0040] Step 6: Cutting The recrystallized molybdenum plate obtained above is cut into a circular disc using a water jet to obtain a molybdenum disc. Abrasive particles may be used at this time to improve cutting efficiency. If the target shape is square, it is cut into a rectangular plate.

[0041] Process 7: Cutting and polishing The surface of the molybdenum disc is machined to a predetermined thickness to remove the surface oxide film and improve flatness. The outer circumference is also machined to a predetermined size. After that, the surface is polished using, for example, a GC grinding wheel to a finish of Ra 1.6 μm or less.

[0042] Step 8: Bonding A backing plate (made of copper, etc.) and bonding material (made of ingot, etc.) are prepared to match the sputtering apparatus. The molybdenum disc and the backing plate are heated on a hot plate and bonded together with the bonding material. A molybdenum sputtering target is obtained by performing this bonding.

[0043] <Example Overview> Molybdenum plates were prepared using various molybdenum raw material powders and subjected to heat treatment at 1300°C for 1 hour, and their crystal grain size was evaluated.

[0044] Furthermore, we also evaluated whether each material would undergo secondary recrystallization after a 1800°C x 5h heat treatment without the 1300°C x 1h heat treatment described above.

[0045] These materials were used to manufacture sputtering targets. Film deposition tests were then conducted using these targets, and the number of particles generated and the film resistance were measured for the thin films.

[0046] [Details of the embodiments of this disclosure] <Examples> As raw materials, we prepared multiple molybdenum-containing powders, grouped according to the characteristics shown in Table 1 below.

[0047] [Table 1]

[0048] "Powder W content" refers to the tungsten content in the molybdenum-containing powder. "Powder K content" refers to the potassium content in the molybdenum-containing powder. The powder raw material group 5 is a molybdenum-containing powder filed on the same day as this application, with an average particle size of 0.1 μm or more and 10 μm or less by the Fsss method, a molybdenum content of 99.99% by mass or more, and a compressive deformation strength of 100 MPa or more and 200 MPa or less. "Fsss particle size" refers to the average particle size by the Fsss method.

[0049] In all raw materials, the tungsten content remains unchanged after sintering, but the potassium content decreases.

[0050] Steps 1 to 8 were performed on the above molybdenum raw material powder to obtain a molybdenum target with a diameter of φ of 4 inches (4 x 2.54 cm). The details are shown in Tables 2 to 5.

[0051] [Table 2]

[0052] [Table 3]

[0053] [Table 4]

[0054] [Table 5]

[0055] To perform the heat treatment process (step 5) under two conditions, identical plates were created from step 1 to step 4 (hot rolling), and these plates were cut to obtain two discs of the same quality. Each disc was then subjected to either the first or second heat treatment condition.

[0056] First heat treatment conditions: Sample numbers 101-117, 201-212 Second heat treatment conditions: Sample numbers 118-136, 213-222 Step 1: Molybdenum raw material powder The molybdenum-containing powder prepared had an average particle size of 4-5 μm (Fsss).

[0057] Process 2: CIP CIP is 2.0 t / cm 2 It was carried out under pressure.

[0058] Step 3: Sintering Sintering was performed at a temperature of 1800°C. The sintering time was adjusted between 3, 6, 10, 15, and 20 hours in a hydrogen atmosphere to obtain sintered bodies with a thickness T of 10 to 40 mm. The thickness of the sintered body here affects the density after hot rolling.

[0059] Process 4: Hot rolling The molybdenum sintered body was heated to 1300°C and rolled until its thickness T reached 7 mm.

[0060] Step 5: Heat treatment To recrystallize the obtained rolled material, heat treatment was performed under two different conditions. The first heat treatment condition was a heat treatment at a temperature of 1300°C for 1 hour, aimed at primary recrystallization of molybdenum. Samples to be subjected to the second condition were not subjected to the first heat treatment. The second heat treatment was a heat treatment at a temperature of 1800°C for 5 hours, aimed at investigating whether secondary recrystallization occurred.

[0061] Step 6: Cutting The plate material, after primary or secondary recrystallization, was cut using a water jet to form a disc with a diameter of 4 inches.

[0062] Process 7: Cutting and polishing In step 6, both sides of a 7mm thick disc were machined to a thickness of approximately 5.5mm. By polishing with a GC grinding wheel to a thickness of 5.0mm, a molybdenum disc with a diameter of φ4inch and a thickness of 5.0mm was obtained. At this time, the flatness was set to 0.2mm or less, and the surface roughness was standardized to approximately Ra 1.0μm.

[0063] Step 8: Bonding The molybdenum disc, which was finished in step 7 as a molybdenum-containing material, was bonded to a copper backing plate using indium as the bonding agent. This resulted in obtaining a sputtering target. <Evaluation Method> <Molybdenum content and impurity content> The molybdenum content (mass%) was calculated using the formula: 100% - 14 elements [Al, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Si, Sn, Na, K, W]. Tungsten (W) is considered an impurity.

[0064] Na, K: The content is measured by atomic absorption spectrometry (contrAA300, Analytical Jena).

[0065] Otherwise: The content is measured by ICP emission spectroscopy (ICP-AES) (Shimadzu Corporation ICPS-8100CL model).

[0066] Oxygen levels are measured as a reference value using infrared absorption spectroscopy (LECO ON836). <density> Density is measured using the underwater gravimetric method (Archimedes method). After the heat treatment in step 5, the sheet material is cut into pieces of any size weighing 10g or more. The air weight, underwater weight, and water temperature are measured. The density is calculated using the following formula. This is the method described in JIS Z 8807.

[0067] Density = {Weight in air / (Weight in air - Weight in water)} x (Density of water - Density of air) + Density of air Furthermore, the relative density is 10.22 g / cm³, which is the theoretical density of molybdenum. 3 This can be expressed by the following formula.

[0068] Relative density [%] = (density / 10.22) x 100 <Grain size (less than 1 mm)> The grain size is measured using the cleavage method specified in JIS G 0551 (2020).

[0069] The metal structure is observed under a microscope, and a test line is set at 1500 μm. The number of grain boundaries (P) crossing this test line is counted, and the average line segment length per crystal grain is taken as the average crystal grain size.

[0070] Specifically, the observation surface will be the surface corresponding to the sputtering surface. In the case of rolled material, it will be the ND surface (rolling surface).

[0071] Four test lines were drawn on the observation surface, two vertically and two horizontally. The area enclosed by the four test lines was a 1500 μm x 1500 μm square. The crystal grain size was calculated using the following formula.

[0072] Average crystal grain size per test line = 1500 μm / P Crystal grain size = Average value of the average grain size calculated from four test lines. If the crystal grain size is 1 mm or larger, the above method cannot be used for measurement. First, measure the crystal grain size according to the measurement method described above when the crystal grain size is 1 mm. If the crystal grain size exceeds 1 mm, determine the correct crystal grain size using the following method. <Crystal grain size (1mm or more)> Measure the length and width of the grain boundaries of five crystal grains visually or under a low-magnification microscope, and determine the average line segment length per crystal grain in the same manner as above. The average of the length and width average line segment lengths is taken as the crystal grain size. <Impurity ratio W, K> If the crystal grain size is less than 1 mm Intragranular impurity content: The plate manufactured in step 7 is finely crushed at cryogenic temperatures. This breaks down the grain boundaries. Subsequently, acid etching is performed, which preferentially corrodes the grain boundaries. As a result, an intragranular sample is obtained. This is collected, dissolved again, and analyzed by ICP to determine the tungsten and potassium content, which is then taken as the intragranular impurity content.

[0073] Specifically, prepare 10 samples measuring 1x20x20mm. The samples, cooled with liquid nitrogen, are crushed in a mortar. This is to expose the particle interfaces. Afterward, sieve the samples through a 150μm mesh. The acid used is hydrochloric acid (12.0 mol / dm³). 3 ), nitric acid (13.8 mol / dm³) 3 Mix the two components in a 1:3 volume ratio and dilute with pure water to twice the volume to prepare a mixed acid. Hereafter, "mixed acid" in this specification refers to this acid. Place the sieved particles (below a 150 μm sieve) after crushing into the mixed acid and dissolve for 8 minutes. The undissolved material has had the particle interface removed and will be used as the sample for analyzing intraparticle impurities. Dissolve this sample further in the mixed acid and analyze the solution by ICP.

[0074] Grain boundary impurity content: The plate is finely crushed at extremely low temperatures. This breaks down the grain boundaries. Subsequently, acid etching is performed, which preferentially corrodes the grain boundaries. Then, the tungsten and potassium content is determined by analyzing the solution containing these grain boundary components using ICP, and this is taken as the grain boundary impurity content.

[0075] Specifically, ten 1x20x20mm samples are prepared. The samples, cooled with liquid nitrogen, are crushed in a mortar. This is to expose the grain interfaces. The samples are then sieved using a 150μm mesh. A mixed acid containing hydrochloric acid, nitric acid, and water is used. The grains separated after crushing (below the 150μm mesh sieve) are placed in the mixed acid and dissolved for 15 minutes to prepare a solution for grain boundary impurity analysis. This solution is then analyzed by ICP.

[0076] For crystal grain size of 1 mm or more Intragranular impurity amount: Prepare samples by cutting plates to a size of 1x1x1mm or larger, ensuring that no grain boundaries are included. The size should be 1x1x1mm or larger, matching the size of the crystal grains. Prepare at least 1g of sample. For example, if one sample is 1x1x1mm, prepare 100 samples. Dissolve a total of 1g or more of the sample in acid. Use a mixed acid containing hydrochloric acid, nitric acid, and water. Analyze the solution using ICP.

[0077] Grain boundary impurity amount: Prepare samples by cutting a plate to a size of 2x2x2mm or larger so that one grain boundary is included. The size should be 2x2x2mm or larger to match the size of the crystal grains. Prepare a total of 1g or more of samples. For example, if the size of one sample is 2x2x2mm, prepare 13 samples. Dissolve the total of 1g or more of the samples in acid. Use a mixed acid containing hydrochloric acid, nitric acid, and water. Analyze the solution by ICP. <Sputtering film deposition test> A magnetron sputtering system of type SRV-4320 manufactured by Shinko Seiki Co., Ltd. was used for molybdenum sputtering. A Si substrate was placed opposite the molybdenum target, and a molybdenum thin film was deposited on it with a target thickness of 300 nm. The chamber was 5 x 10 -4 The system was evacuated to below Pa. Then, argon gas was flowed at 25 sccm, and the output was set to 500W. A target size of φ4 inch x T5 mm was used.

[0078] <Number of particles generated> A Lasertec OPTELICS HYBRID+ laser microscope was used to measure the particle count of the deposited molybdenum thin film. Surface roughness was measured in a 1mm x 1mm area, and irregularities with a height of 20nm to 1μm were defined as particles, and their number was counted.

[0079] <Thin film sheet resistance> A Napson RT-70V was used to measure the film resistance. The sheet resistance was measured by bringing the measurement probe into contact with the deposited 300 nm molybdenum thin film.

[0080] <Rating> The "powder group" in Tables 2 and 3 corresponds to the powder group in Table 1.

[0081] In the "W content" column, "Total" refers to the mass content of tungsten in the entire material containing molybdenum. "Intragranular" refers to the mass content of tungsten within a single crystal grain. "Grain boundary" refers to the mass content of tungsten at a grain boundary. "Intragranular W" / "Grain boundary W" is the ratio of W.

[0082] In the "K content" column, "Total" refers to the mass content of potassium in the entire molybdenum-containing material. "Intragranular" refers to the mass content of potassium within the crystal grains. "Grain boundary" refers to the mass content of potassium at the grain boundaries. "Intragranular K" / "Grain boundary K" is the ratio of K.

[0083] Samples 101 to 117 show good results, with a particle count of 34 or less and a thin film sheet resistance of 1.5 Ω or less. In contrast, samples 201 to 212 show an increase in both particle count and thin film resistance.

[0084] Samples 118 to 136 show good results, with a particle count of 29 or less and a thin film sheet resistance of 1.5 Ω or less. In contrast, samples 213 to 222 show an increase in both particle count and thin film resistance.

[0085] We evaluated secondary recrystallization and the resulting ease of deformation at high temperatures. In Table 5, "secondary recrystallization" is defined as whether a crystal grain size of 1 mm or larger is achieved at 1800°C for 5 hours, which is easily carried out industrially, as described above. In Table 5, regardless of whether secondary recrystallization was performed, samples with a thickness T of 1 mm, a width B of 20 mm, and a length L of 120 mm were prepared for sample numbers 118 to 212.

[0086] Figure 3 shows a diagram of an apparatus for measuring the ease of deformation at high temperatures. As shown in Figure 3, the distance between the two support columns 401 was set to 100 mm. A sample 402 was placed on top of them. A force of 150 g was applied to the center of the sample in the direction indicated by arrow 403, and this condition was maintained at a temperature of 1800°C for 10 hours. Samples with a deformation amount Z of less than 1 mm were designated as "A" in the "High-temperature deformation 1800°C x 10h" column of Table 5, and samples with a deformation amount Z of 1 mm or more were designated as "B". It can be seen that the deformation amount is smaller after secondary recrystallization. <Influence on density> Next, to investigate the effect of density, sintered bodies were produced in steps 1-3 using raw materials 1-5, with thicknesses of T15mm, T12mm, and T10mm. These were then rolled to T7mm in step 4 to investigate the changes in density after hot rolling. The heat treatment temperature in step 5 was set to the first heat treatment condition of 1300°C x 1h. The obtained molybdenum sheets were processed into molybdenum targets through steps 5-8, and film deposition was performed by sputtering.

[0087] [Table 6]

[0088] For further comparison, we manufactured the molybdenum target using the commonly used hot pressing (HP) method. The HP was performed under the typical conditions for molybdenum HP, 1600°C x 40MPa x 3h, to obtain a molybdenum sintered body. The obtained sintered body was processed into a molybdenum target through steps 5-8, similar to the rolled material, and film deposition was performed by sputtering. The heat treatment temperature in step 5 was set to 1300°C x 1h, which is the first heat treatment condition.

[0089] [Table 7]

[0090] [Table 8]

[0091] As a result, the density was 10.15 g / cm³. 3 It was found that the number of particles generated increases below the following thresholds. Furthermore, even when using the same raw material powder as the rolled material, the HP product resulted in a higher number of particles being generated compared to the rolled material.

[0092] In rolled materials, significant grain boundary movement occurs during recrystallization caused by heat treatment after rolling, whereas in HP products, only sintering is performed, resulting in insufficient grain boundary segregation of W and K. (Note 1) A molybdenum-containing material having a grain size of 25 μm or larger, a density of 10.15 g / cm³ or larger, a molybdenum content of 99.95% by mass or larger, and a mass ratio of intragranular tungsten content to intergranular tungsten content (intragranular W / intergranular W) of 0.8 or less. (Note 2) A material containing molybdenum as described in Appendix 1, wherein the grain size is 1 mm or larger, and the value of the intragranular W / grain boundary W is 0.7 or less. (Note 3) A molybdenum-containing material as described in Appendix 1 or 2, wherein the ratio of intragranular potassium content to grain boundary potassium content, i.e., intragranular K / grain boundary K, is 0.7 or less. (Appendix 4) A material containing molybdenum as described in Appendix 3, wherein the intragranular K / granular boundary K value is 0.6 or less. (Appendix 5) Density 10.18g / cm 3 A material containing molybdenum as described in any one of the appendices 1 to 4, which is 99.8% or more. (Note 6) A material containing molybdenum as described in any one of the appendices 1 to 5, wherein the molybdenum content is 99.999% by mass or more. (Note 7) A material containing molybdenum as described in any one of the appendices 1 to 6, having a tungsten content of 200 ppm or less. (Note 8) A material containing molybdenum as described in any one of the appendices 1 to 7, wherein the total potassium content is 20 ppm or less. (Note 9) A material containing molybdenum as described in any one of the appendices 1 to 8, having the shape of a plate or a target.

[0093] The embodiments and examples disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included.

Claims

1. Crystal grain size 25μm or more, density 10.15g / cm ３ A molybdenum-containing material having a molybdenum content of 99.95% by mass or less, and a molybdenum content ratio of 99.95% by mass or more, and a molybdenum-containing material having a molybdenum content ratio of 99.95% by mass or more, and a molybdenum-containing material having a molybdenum content ratio of 99.95% by mass or more, and a molybdenum-containing material having a molybdenum content ratio of 99.95% by mass or more, and a molybdenum-containing material having a molybdenum content ratio of 99.95% by mass or less content ratio of

2. A material containing molybdenum according to claim 1, wherein the crystal grain size is 1 mm or more.

3. A molybdenum-containing material according to claim 1 or 2, wherein the value of intragranular K / grain boundary K, which is the ratio of intragranular potassium content to grain boundary potassium content, is 0.7 or less.

4. The molybdenum-containing material according to claim 3, wherein the value of the intragranular K / granular boundary K is 0.6 or less.

5. Density 10.18g / cm ３ A material containing molybdenum according to claim 1 or 2, wherein the molybdenum content is 99.8% or more.

6. A molybdenum-containing material according to claim 1 or 2, wherein the molybdenum content is 99.999% by mass or more.

7. A molybdenum-containing material according to claim 1 or 2, wherein the tungsten content is 200 ppm or less.

8. A molybdenum-containing material according to claim 1 or 2, wherein the potassium content is 20 ppm or less.

9. A molybdenum-containing material according to claim 1 or 2, having the shape of a plate or a target.

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