JP2011214039A - Method for producing sputtering target material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reducing the permeability of a target material by the magnetron sputtering method.SOLUTION: A sputtering target material by the casting method or the powder metallurgical processing method is composed of one or more kinds of elements Fe, Co, and Ni of fourth period of Group 8A of the periodic table, or mainly consisting of elements Fe, Co and Ni of fourth period of Group 8A, and at least one element to be selected among the element group of Al, Ag, Au, B, C, Ce, Cr, Co, Cu, Ga, Ge, Dy, Fe, Gd, Hf, In, La, Mn, Mo, Nb, Nd, Ni, P, Pd, Pt, Ru, Si, Sm, Sn, Ta, Ti, V, W, Y, Zn and Zr. After casting the compositions, or after executing the hot-forming of the powder and cooling it, the powder is worked into the dimension of the target material by machining. The target material is heated from the room temperature to 500-900°C, and then, cooled to the room temperature at the post-cooling rate of 2,160-540,000°C/hr, and then, subjected to the heat treatment to form the target material with its permeability being reduced.

Description

  The present invention relates to a method for producing a sputtering target material used for forming a thin film by a sputtering method. The present invention relates to a method for manufacturing a sputtering target which is made of an alloy material having magnetism and is used for manufacturing, for example, a magnetic recording medium or a magneto-optical (MO) recording medium and having a high magnetic field transmittance (PTF).

  For example, sputtering target materials are widely used for forming thin films of metals, alloys, semiconductors, ceramics, dielectrics, ferroelectrics or cermets. In the sputtering process, when a material source, that is, a sputtering target, is bombarded with ions generated from a plasma, the ions remove or eject atoms or molecules from the surface of the sputtering target, and the ejected atoms or molecules are: Deposited on the substrate to form a thin film coating. Sputtering is widely used for the formation of underlayers, intermediate layers, magnetic layers, dielectric layers or protective film layers in the manufacture of thin film data and information recording and retrieval media (eg, magnetic and magneto-optical (MO) media, etc.). ing.

  In general, magnetron sputtering is used to form soft magnetic underlayers (SULs) and magnetically strong recording layers of these magnetic recording media. This magnetron sputtering method is a sputtering method that enables high-speed film formation by placing a magnet behind the sputtering target material, allowing the magnetic field to pass through the surface of the sputtering target material, and converging the plasma to the transmitted magnetic field. is there.

  For example, alloys used to form soft magnetic underlayers (SULs) of magnetic recording media and magnetically strong recording layers generally have high magnetic permeability. That is, it is described that in a pure Co sputtering target material, the permeability of the pure Co sputtering target material is lowered by controlling the crystal structure, and a transmission magnetic field necessary and sufficient for the magnetron sputtering method is formed on the surface of the sputtering target material. (For example, refer to Patent Document 1). Further, it is described that the magnetic permeability of the sputtering target material is lowered by applying distortion during solidification molding at a low temperature, and a transmission magnetic field necessary and sufficient for the magnetron sputtering method is formed on the surface of the sputtering target material (for example, patents). Reference 2).

Special table 2001-514325 JP 2008-127588 A

  The magnetron sputtering method described above is characterized in that a magnetic field is transmitted through the sputtering surface of the sputtering target material, so that the magnetic material used for forming soft magnetic underlayers (SULs) and magnetically strong recording layers of magnetic recording media. When the magnetic permeability of the sputtering target material itself such as an alloy is high, it becomes difficult to form a transmission magnetic field necessary and sufficient for the magnetron sputtering method on the sputtering surface of the sputtering target material. Therefore, the problem to be solved by the present invention is to provide a method for reducing the magnetic permeability of the sputtering target material itself in the magnetron sputtering method as much as possible. As a method for producing a sputtering target material, a method of solidifying and forming a powder hot is common.

  As an example of a technique for reducing the magnetic permeability, there is a method of reducing the magnetic permeability by controlling the crystal structure in a pure Co sputtering target material as disclosed in Patent Document 1. However, the method of Patent Document 1 can be applied only to a pure Co sputtering target material, and cannot be applied to a material whose main component is Co whose crystal structure changes or a material other than Co. Further, as in Patent Document 2, there is a method in which the magnetic permeability is reduced by applying strain at the time of solidification molding of the powder at a low temperature. However, the method of Patent Document 2 has a problem that it cannot be applied to a temperature at which strain is recovered.

  In order to solve the above-mentioned problems, the inventors have intensively studied. As a result, the sputtering target material obtained by the casting method or the powder metallurgy method is distorted by heat treatment, and the crystal structure and the sputtering target composition. The inventors have found that the magnetic permeability of the sputtering target material itself can be reduced regardless of the temperature, and have reached the present invention.

  That is, the means of the present invention for solving the above problems is a sputtering target material produced by a casting method or a powder metallurgy method, and is Fe, Co, Ni, which is an element of group 4A of the 8A group of the periodic table. Or one or more elements selected from Fe, Co, and Ni, which are four-period elements of Group 8A, and the total is 60 at. %, And Al, Ag, Au, B, C, Ce, Cr, Cu, Ga, Ge, Dy, Gd, Hf, In, La, Mn, Mo, Nb, Nd, Consisting of at least one element other than the main component selected from the element group consisting of P, Pd, Pt, Ru, Si, Sm, Sn, Ta, Ti, V, W, Y, Zn, and Zr, and inevitable impurities, The raw material of the sputtering target material is cast or powder is hot-formed, and then the cooled compact is further machined to a predetermined size to obtain a sputtering target material. Furthermore, the sputtering target material is heated from room temperature to a temperature of 500 to 900 ° C., and then cooled from the above heating temperature to the vicinity of room temperature at a cooling rate of 2160 to 540000 ° C./hr. It is a manufacturing method of a sputtering target material.

  The present invention is composed of Fe, Co, Ni, which are elements of the 4A group of the periodic table 8A, or Fe, Co, Ni, which is the element of the 4A group of the periodic table 8A group, Al, Ag, Au, B, C, Ce, Cr, Cu, Ga, Ge, Dy, Gd, Hf, In, La, Mn, Mo, Nb, Nd, P, Pd, Pt, Ru, Si, Sm, Casting from the material of the sputtering target material or hot forming of the powder of the material, comprising at least one element other than the main component selected from the element group consisting of Sn, Ta, Ti, V, W, Y, Zn and Zr, Further, by performing heat treatment after cooling, a magnetic sputtering target material capable of forming a transmission magnetic field necessary and sufficient for performing stable magnetron sputtering can be manufactured.

Hereinafter, the present invention will be described in detail.
It consists of Fe, Co, Ni of the 4th group element of the 8A group of the periodic table, or Fe, Co, Ni of the 4th group element of the 8A group of the periodic table as the main components, and Al, Ag, Au B, C, Ce, Cr, Co, Cu, Ga, Ge, Dy, Fe, Gd, Hf, In, La, Mn, Mo, Nb, Nd, Ni, P, Pd, Pt, Ru, Si, Sm , Sn, Ta, Ti, V, W, Y, Zn and at least one element selected from the element group consisting of Zn and Zr and unavoidable impurities, and the element as the main component is at least 60 at. In the casting method, each material is made by vacuum melting and then cast and molded, or in the powder metallurgy method, each powder as the material is HIP, that is, hot isostatic pressing method or upset And hot forming such as a hot extrusion method or the like, and cooling, and these formed bodies are machined into predetermined dimensions to obtain a sputtering target material.

  In the present invention, the molded product is further heated to 500 to 900 ° C., and then cooled to room temperature at a cooling rate of 2160 to 540000 ° C./hr by air cooling or water cooling to obtain a sputtering target material. The aforementioned cooling rate in this method depends on the cooling method and the dimensions of the sputtering target material. In the above-described manufacturing method of the present invention, the magnetic permeability can be reduced by distorting the sputtering target material by rapid cooling. The reason why the above-mentioned heating temperature condition is 500 ° C. or more is that if the temperature is less than 500 ° C., a sufficient quenching effect cannot be obtained. The reason for setting the heating temperature to 900 ° C. or lower is that the properties deteriorate due to the formation of a compound having a high magnetic permeability at temperatures exceeding 900 ° C. It is. For example, in the case of a sputtering target material made of Co and Fe powder, if the sputtering target material is heated to a temperature exceeding 900 ° C., a Co—Fe alloy having a high magnetic permeability is formed, and the effect of reducing the magnetic permeability due to strain is negated. Because it is.

  Hereinafter, the present invention will be specifically described by way of examples. Since some of the transmission magnetic field of the sputtering target material is caused by the magnetic permeability of the sputtering target material, in the present invention, the transmission magnetic field of the sputtering target material was evaluated by measuring the magnetic permeability. . On the other hand, the magnetic permeability changes sensitively with strain. That is, when the strain is large, the magnetic permeability is greatly reduced, and when the strain is small, the magnetic permeability is decreased. Therefore, as a method for measuring the magnetic permeability, a sputtering target material was produced by machining into a ring test piece having an outer diameter of 15 mm, an inner diameter of 10 mm, and a height of 5 mm, and the magnetic permeability was adjusted with a BH tracer at an applied magnetic field of 8 kA / m. It was measured. When the magnetic permeability is low, the transmitted magnetic field increases, and when the magnetic permeability is high, the transmitted magnetic field decreases. A material composed of Fe, Co, Ni of the 4th periodic element of the 8A group of the periodic table, or at least one of Fe, Co, Ni of the 4th periodic element of the 8A group of the periodic table, and Al, Ag, Au, B, C, Ce, Cr, Co, Cu, Ga, Ge, Dy, Fe, Gd, Hf, In, La, Mn, Mo, Nb, Nd, Ni, P, Pd, Pt, It consists of at least one element selected from the element group consisting of Ru, Si, Sm, Sn, Ta, Ti, V, W, Y, Zn and Zr, and the main component is at least 60 at. %, And the raw material is Table 1-1, Table 1-2, Table 2-1, Table 2-2, Table 3-1, Table 3-2, Table 4-1, Table 4-2, Table. 4-1, Table 4-1, Table 6-1, Table 6-2, Table 7-1 and Table 7-2 are heated to the heating temperatures shown in FIG. The heat processing which cools by any of these was given. Examples 1 to 60, Examples 69 to 128, Examples 136 to 195, Examples 204 to 263, Examples 272 to 331, Examples 340 to 399, Examples 408 to 413, and Examples 420 to 425 are Examples of the present invention, comparative examples 61-68, comparative examples 129-135, comparative examples 196-203, comparative examples 264-271, comparative examples 332-339, comparative examples 400-407, comparative examples 414-419 and Comparative examples 426 to 431 are comparative examples for the present invention. Among these, Table 1-1 to Table 3-2 and Table 7-1 are target materials prepared by the powder metallurgy method, and Table 4-1 to Table 6-2 and Table 7-2 are targets prepared by the casting method. It is a material. In the comparative example, at least one condition of the heating temperature or the cooling rate is out of the condition of the present invention.

  Each target material has its surface polished after the heat treatment by heating and cooling described above. In addition, the above-mentioned cooling rate at the time of shaping | molding was computed by evaluating the temperature history from shaping | molding temperature to 300 degreeC with a thermo tracer.

  Comparative Example 65 was heated to 800 ° C., slowly cooled at a cooling rate of 2000 ° C./hr and heat-treated, and the magnetic permeability was 199, whereas Example 41 having the same sputtering target composition was 800 ° C. And the heat treatment was performed by air cooling at a cooling rate of 2160 ° C./hr and the magnetic permeability decreased to 157, and thus the transmitted magnetic field increased. On the other hand, Example 60 was heated at 800 ° C., water-cooled at a cooling rate of 540000 ° C./hr, and heat-treated. The magnetic permeability decreased to 127 and the transmitted magnetic field was further increased and improved. Further, Comparative Example 66 was heated to 950 ° C., heat-cooled by water cooling at a cooling rate of 540000 ° C./hr, and the magnetic permeability was 197, whereas Example 59 was heated to 900 ° C. and the cooling rate was 540000. It is heat-treated by cooling with water at ° C./hr, and the magnetic permeability is improved to 129. Furthermore, in Comparative Example 68 and Example 40 having the same sputtering target composition, Comparative Example 68 is heated to 400 ° C., heat-cooled with water at a cooling rate of 2160 ° C./hr, and has a magnetic permeability of 199. On the other hand, Example 40 was heated to 500 ° C., air-cooled at a cooling rate of 2160 ° C./hr and heat-treated, and the magnetic permeability was improved to 159.

Claims (1)

  A sputtering target material produced by a casting method or a powder metallurgy method, and comprising a raw material composed of at least one element selected from the group consisting of Fe, Co, and Ni, which are elements of Group 4A of the 8A group of the periodic table Or at least one element selected from the group of elements consisting of Fe, Co, and Ni, which are four-period elements of Group 8A, and the total is 60 at. %, And the balance is Al, Ag, Au, B, C, Ce, Cr, Cu, Ga, Ge, Dy, Gd, Hf, In, La, Mn, Mo, Nb, Nd, A powder raw material composed of at least one element selected from the element group consisting of P, Pd, Pt, Ru, Si, Sm, Sn, Ta, Ti, V, W, Y, Zn, and Zr and inevitable impurities is used. Then, as a manufacturing method of the solidified and formed sputtering target material, after casting the powder of these compositions, or after forming the powder hot and cooling, it is processed into a predetermined sputtering target material size by machining, and further from room temperature to 500 Heating to a temperature of ˜900 ° C., and then cooling from the above heating temperature to room temperature at a cooling rate of 2160 to 540000 ° C./hr. Method of manufacturing a sputtering target material for grayed.