Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/05—Metallic powder characterised by the size or surface area of the particles
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
  • C22C27/04—Alloys based on tungsten or molybdenum
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/14—Metallic material, boron or silicon
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering

Definitions

• Powder containing molybdenum has been disclosed, for example, in JP 2005-133197 A (Patent Document 1), JP 2005-133198 A (Patent Document 2), WO 2011-004887 A (Patent Document 3), WO 2019-176962 A (Patent Document 4), JP 2005-314714 A (Patent Document 5), and JP 2005-314715 A (Patent Document 6).
• the powder containing molybdenum disclosed herein has an average particle size measured by the Fsss method of 0.1 ⁇ m or more and 10 ⁇ m or less, a molybdenum content of 99.99 mass% or more, and a compressive deformation strength of more than 0 MPa and 200 MPa or less.
• particles can be reduced by making the purity 99.999% or more, the relative density 98% or more, the average particle size 45 ⁇ m or less, and the radiation dose 0.03 cph/cm 2 or less.
• Molybdenum powder is manufactured by hot pressing (HP).
• EUV mask blanks are coated with a Mo/Si multilayer film, and the presence of 1 nm unevenness in the film can cause a phase shift of 50° or more for a wavelength of 13.5 nm, which can lead to defects.
• Using a high-density molybdenum target made from the powder containing high-purity molybdenum as disclosed herein can help reduce defects during molybdenum film formation.
• the powder containing molybdenum according to the present disclosure has an average particle size measured by the Fsss method of 0.1 ⁇ m or more and 10 ⁇ m or less, a molybdenum content of 99.99 mass% or more, and a compressive deformation strength of more than 0 MPa and 200 MPa or less.
• the molybdenum content is 99.99% by mass or more, which makes it easy to reduce the compressive deformation strength. If the compressive deformation strength exceeds 200 MPa, the molybdenum-containing powder becomes difficult to deform, and voids are more likely to occur during sintering.
• the average particle size measured by the Fsss method is less than 0.1 ⁇ m, it will be prone to ignition and difficult to handle. If the average particle size measured by the Fsss method exceeds 10 ⁇ m, the density of the sintered body produced from the powder containing molybdenum will tend to decrease. More preferably, the average particle size measured by the Fsss method is 1 ⁇ m or more and 9 ⁇ m or less. This range allows for the safest handling and improves the density of the sintered body.
• the tungsten content is 90 ppm or less. If the tungsten content is in this range, the compressive deformation strength of the powder containing molybdenum can be reliably reduced. More preferably, the tungsten content is 0 ppm or more and 10 ppm or less.
• the molybdenum content is 99.999% by mass or more. If the molybdenum content is within this range, the compression deformation strength of the powder containing molybdenum can be reliably reduced.
• the target is made of the above-mentioned molybdenum-containing powder, and the number of particles in the sputtered molybdenum thin film is 50 or less within 1 mm2 .
• the sintered density is 93% when sintered at a temperature of 1800°C for 200 minutes, but the sintered density of the product disclosed here is 98% or more. This makes it possible to provide a high-density target with low porosity.
• the relative density is 90% or more after 60 minutes of sintering, but with the product disclosed here, when sintering at 1800°C, the relative density is 97.5% or more after 60 minutes of sintering. This allows for reduced sintering costs.
• Step 2 Sieving of raw material The refined MoO3 powder is passed through a sieve with a specified mesh size, and the raw material is passed through the sieve to remove coarse and fine powders.
• the mesh size of the sieve is appropriately changed depending on the raw material and the target molybdenum powder particle size.
• Step 3 One-step reduction (MoO 3 ⁇ MoO 2 )
• MoO3 powder produced in step 1 is sieved.
• the sieved powder is then loaded into a molybdenum boat (molybdenum content of 99.99% by mass or more).
• the optimal reduction conditions temperature, hydrogen flow rate, amount of raw material input, equipment used, etc. are appropriately selected to obtain the target powder particle size. This performs a single-stage reduction.
• Step 4 Intermediate Sieving The MoO2 powder is sieved.
• the mesh size of the sieve is appropriately changed depending on the raw material and the target particle size of the molybdenum powder.
• Step 5 Two-stage reduction (MoO 2 ⁇ Mo)
• MoO2 powder after intermediate sieving is loaded into a molybdenum boat (molybdenum content of 99.99% by mass or more).
• the reduction conditions are adjusted according to the target Fsss particle size.
• the powder is reduced until it becomes a powder containing metallic molybdenum, and is removed from the boat.
• Step 6 Final Sieving The obtained molybdenum-containing powder is sieved.
• the mesh size of the sieve is appropriately changed depending on the raw material and the target particle size of the molybdenum-containing powder.
• Example 1 of Sample No. 1 below step 1: refining, step 2: raw material sieving, step 3: first-stage reduction, step 4: intermediate sieving, step 5: second-stage reduction, step 6: final sieving, step 7: sintering, step 8: sputtering, and thin film evaluation are carried out.
• Step 1 Refining MoO3 powder is heated, sublimated, and then rapidly cooled to obtain MoO3 powder with a low W concentration.
• the sublimation temperature is preferably 500°C or higher and lower than 800°C. Below 500 ° C., sublimation of the MoO 3 powder does not proceed easily. Above 650 ° C., WO 3 powder sublimation increases, making it difficult to obtain MoO 3 powder with a low W content.
• MoO3 powder with a low W content can be obtained.
• Step 2 Sieving the raw material The MoO3 powder refined in step 1 is sieved.
• the reduction temperature is preferably between 450°C and 650°C. If it exceeds 650°C, the raw materials may melt as they are close to their melting point. If it is below 450°C, the reduction of the raw materials in the boat may not proceed smoothly.
• the hydrogen flow rate is preferably 5 m 3 /h or more. If it is less than 5 m 3 /h, the reduction of the raw material in the boat may not proceed well.
• the reduction temperature is preferably 600°C or higher. If it is below 600°C, the reduction of the raw materials in the boat may not proceed smoothly.
• Sputtering was performed under the conditions of Ar sputtering gas and 300 W sputtering power.
• a 0.3 ⁇ m-thick high-purity metal molybdenum thin film was formed over the entire surface of a Si wafer with a diameter D of 100 mm.
• Sample No. 101 was produced according to Patent Document 1 (JP Patent Publication No. 2005-133197).
• Sample No. 102 was produced according to Patent Document 3 (WO Publication No. 2011-004887).
• Mo in Tables 1 and 2 indicates the molybdenum content (mass%) in the powder containing molybdenum.
• the molybdenum content is analyzed using the flat cell method of glow discharge mass spectrometry (GD-MS).
• GD-MS glow discharge mass spectrometry
• Compressive strength refers to the strength measured in a microcompression test (single grain crushing strength).
• the unit is "MPa.”
• the equipment used is a Shimadzu MCT-510 microcompression tester. A small amount of particles is scattered on the sample stage. A load is applied at a constant increasing rate to a single particle placed between the upper flat indenter and the lower sample stage. From the deformation behavior of the sample at this time, the crushing strength of the particle is measured as the compressive deformation strength. The test force and compression displacement during the deformation process of the sample are measured and recorded.
• Fsss refers to the average particle size measured by the Fsss method.
• the unit is " ⁇ m”.
• Fsss is measured by the Fischer method.
• the equipment used for the measurement is a Fisher Sub-Sieve Sizer Model 95 made by Fisher Scientific.
• a true density sample is filled into a sample tube, and the porosity is calculated from the sample height. Air at 1 MPa pressure is then passed through the tube, and the manometer water level is read as a number on a calculator chart, and this value is expressed as the average particle size in ⁇ m.
• Fsss represents the average particle size of the powder, and the lower the value, the smaller the average particle size.
• W indicates the tungsten content (ppm mass%) in the molybdenum-containing powder.
• the tungsten content is analyzed using the flat cell method of glow discharge mass spectrometry (GD-MS).
• GD-MS glow discharge mass spectrometry
• Relative density 200Min is the relative density of the sintered body after sintering for 200 minutes in process 7.
• Relative density 60Min is the relative density of the sintered body after sintering for 60 minutes in process 7. The density of the sintered body is measured using the Archimedes method.
• the powder containing molybdenum has a high compressive strength. As a result, the relative density of the sintered body produced from this powder is low.
• Table 3 shows that the molybdenum thin films produced by sputtering targets made from sample numbers 4, 7, 11, and 15 had a small number of particles, and good results were obtained. In contrast, the comparative sample numbers 101, 103, and 104 had a large number of particles, and the quality of the targets was reduced.

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• Chemical Kinetics & Catalysis (AREA)
• Physical Vapour Deposition (AREA)
• Powder Metallurgy (AREA)

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• 2024
  • 2024-10-03 JP JP2025511362A patent/JPWO2025079493A1/ja active Pending
  • 2024-10-03 WO PCT/JP2024/035427 patent/WO2025079493A1/ja active Pending

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