Method for producing sputtering target material
Provided is a method of producing a target material with reduced particle generation during sputtering, which is a method of producing a sputtering target material whose material is an alloy M, including a sintering step of sintering a mixed powder obtained by mixing a first powder and a second powder. A material of the first powder is an alloy M1 in which the proportion of a B content is from 40 at. % to 60 at. %. A material of the second powder is an alloy M2 in which the proportion of a B content is from 20 at. % to 35 at. %. The proportion of a B content in the mixed powder is from 33 at. % to 50 at. %. A metallographic structure including a (CoFe) 2 B phase and a (CoFe)B phase is formed in the sintering step. A boundary length per unit area Y (1/μm), which is obtained by measuring a boundary length between the (CoFe) 2 B phase and the (CoFe)B phase using a scanning electron microscope, and a proportion X (at. %) of a B content of the alloy M satisfy the expression Y <−0.0015×( X −42.5) 2 +0.15.
1 . A method of producing a sputtering target material composed of an alloy M comprising B, and Co and/or Fe, with a balance consisting of inevitable impurities, the method comprising a sintering step of sintering a mixed powder obtained by mixing a first powder and a second powder,
wherein the first powder and the second powder each consist of particles,
wherein each particle forming the first powder is composed of an alloy M1 comprising B, and Co and/or Fe, with a balance consisting of inevitable impurities,
wherein a proportion of a B content to a total of a Co content, an Fe content, and a B content in the alloy M1 is from 40 at. % to 60 at. %,
wherein each particle forming the second powder is composed of an alloy M2 comprising B, and Co and/or Fe, with a balance consisting of inevitable impurities,
wherein a proportion of a B content to a total of a Co content, an Fe content, and a B content in the alloy M2 is from 20 at. % to 35 at. %,
wherein a proportion of a B content to a total of a Co content, an Fe content, and a B content in the mixed powder is from 33 at. % to 50 at. %,
wherein a metallographic structure comprising a (CoFe) 2 B phase in which an atomic ratio of a sum of a Co content and an Fe content (Co content+Fe content) to a B content [(Co content+Fe content):B content] is 2:1, and a (CoFe) B phase in which the atomic ratio [(Co content+Fe content):B content] is 1:1 is formed in the sintering step, and
wherein a boundary length per unit area Y (1/μm), which is obtained by measuring a boundary length between the (CoFe) 2 B phase and the (CoFe) B phase using a scanning electron microscope, and a proportion X (at. %) of a B content to a total of a Co content, an Fe content, and a B content in the alloy M satisfy the following expression:
Y<− 0.0015×( X− 42.5) 2 +0.15.