JP2013224481A - Manufacturing method of sputtering target material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a sputtering target material capable of solving such a problem that a sputtering target material causes deformation and peeling due to thermal expansion difference between the sputtering target material and a backing plate or a backing tube, in manufacturing the sputtering target material by a physical deposition method.SOLUTION: In a method for manufacturing a sputtering target material, a bulk body is formed by directly depositing particles having the same composition as a base substance on the base substance with a thickness of 0.1-2.0 mm.

Description

  The present invention relates to a method for producing a sputtering target material.

As a method for producing a sputtering target material, a casting method, an electrolytic plating method, a plastic working method, a pressure sintering method and the like are generally known. In recent years, as a method for obtaining a sputtering target material which is simpler and higher in production efficiency than these methods, a physical method in which particles having a sputtering target composition are deposited on a backing plate or a backing tube by a thermal spraying method or a cold spray method. A manufacturing method using a deposition method has been proposed.
In the thermal spraying method, particles with a sputtering target composition are passed through a high temperature region of a combustion flame or plasma flame to heat the particles to their melting point or higher, and the molten particles collide with a backing plate to solidify and deposit on the substrate. It is a method to make it. The cold spray method is a method in which particles are accelerated by a supersonic gas flow below the melting point or softening point temperature of the particles and collide with a backing plate or a backing tube and deposited by plastic deformation of the particles. It is said that a thick film can be formed.

According to these physical deposition methods, it is effective in that a near net shape sputtering target material can be easily manufactured and can be regenerated by directly forming it on a used sputtering target material, resulting in cost merit. It is a technique.
The backing plate used in the above-described physical deposition method is generally made of Cu or Al having excellent thermal conductivity. Further, in a recently proposed cylindrical sputtering target, a stainless alloy or Ti is used as a backing tube in order to ensure rigidity.

  When manufacturing a sputtering target by these physical deposition methods, in order to form the sputtering target material directly on the backing plate or the backing tube, the heat between the sputtering target material and the backing plate or the backing tube due to the temperature rise during sputtering is used. There has been a problem that the sputtering target material is deformed or peeled off due to the bimetallic effect due to the expansion difference. To solve this problem, a sputtering target structure having an intermediate layer having a thermal expansion coefficient intermediate between the sputtering target material and the backing plate or backing tube is proposed between the sputtering target material and the backing plate or backing tube. (Patent Document 1).

Special table 2010-526211 gazette

According to the method for manufacturing a sputtering target of Patent Document 1, stress due to a difference in thermal expansion associated with a temperature rise of a sputtering target material and a backing plate or a backing tube can be relieved at the time of sputtering. It is said that a certain effect can be obtained.
However, according to the study by the present inventors, it has been confirmed that in the production by the physical deposition method, when the sputtering target material is formed on the backing plate or the backing tube, there is a considerable thermal influence on the substrate. For example, when a refractory metal such as Mo or W is selected as the sputtering target material, it is necessary to form the sputtering target material at a high temperature, and the thermal expansion of the composition selected as the sputtering target material and the backing plate or backing tube. There is a mismatch between the coefficients. For this reason, even if there is an intermediate layer with a thermal expansion coefficient intermediate between that of the sputtering target material and the backing plate or tube, the stress due to the difference in thermal expansion is sufficiently absorbed in the cooling process after the sputtering target material is formed. It is difficult to avoid deformation and peeling of the sputtering target material.

  It is an object of the present invention to produce a sputtering target material that can solve the problem of deformation and delamination of the sputtering target material due to a difference in thermal expansion between the sputtering target material and the backing plate or backing tube during the production of the sputtering target material by a physical deposition method. Is to provide a method.

  The present inventor examines the above-described problems when forming a sputtering target material by a physical deposition method, and forms a bulk body by depositing powder particles having the same composition on a substrate having the same composition as the sputtering target material. As a result, it has been found that the problem of deformation and peeling of the sputtering target material can be greatly improved, and the present invention has been achieved.

  That is, the present invention is a method for producing a sputtering target material in which a bulk body is formed by directly depositing particles having the same composition as a substrate on a substrate having a thickness of 0.1 to 2.0 mm.

  INDUSTRIAL APPLICABILITY The present invention can solve the problem of deformation and peeling of a sputtering target material that is unavoidable in production in the production of a sputtering target material by a physical deposition method, and is an effective technique for producing a sputtering target.

It is the figure which represented the manufacturing method of this invention typically. It is an example of the cross-sectional photograph of the sputtering target material manufactured with the manufacturing method of this invention. It is another example of the cross-sectional photograph of the sputtering target material manufactured with the manufacturing method of this invention. It is a cross-sectional photograph of the sputtering target material used as a comparative example.

As described above, an important feature of the present invention is that the sputtering target material and the substrate have the same composition. This will be described in detail below.
FIG. 1 is a diagram schematically showing the production method of the present invention. First, a base 2 having the same composition as the sputtering target material and a thickness of 0.1 to 2.0 mm is prepared. At this time, the substrate 2 is a flat plate in the case of a planar type sputtering target material, and a cylindrical body in the case of a cylindrical type sputtering target material. The reason why the substrate 2 has the same composition as the sputtering target material in the present invention is to prevent deformation and peeling due to the difference in thermal expansion coefficient between the bulk body 1 and the substrate 2 that occurs in the cooling process after the formation of the bulk body 1 accompanied by temperature rise. Because.

Next, as shown in FIG. 1, particles 3 having the same composition as that of the substrate 2 are directly deposited on the substrate 2 to form a bulk body 1 serving as a sputtering target material. As a method for forming the bulk body 1 by depositing particles on the substrate 2 in the present invention, a physical deposition method represented by a thermal spraying method or a cold spray method can be applied.
The thermal spraying method is a method in which particles are passed through a high temperature region of a combustion flame or a plasma flame, the particles are heated to the melting point or higher, the molten particles are collided on the substrate, and solidified and deposited on the substrate. Since not only metal materials but also ceramics can be deposited, it is advantageous in terms of wide application range of materials. Moreover, the thermal spraying method is excellent in that it can be manufactured regardless of the shape and size with a single facility from a planar type to a cylindrical type.
The cold spray method is a method in which particles are accelerated by a supersonic gas flow below the melting point or softening point temperature of the particles, collide with the surface of the substrate, and are deposited by plastic deformation of the particles, and internal defects are generated. It can be suppressed and a dense bulk body can be formed.

The composition of the substrate and particles applicable in the present invention is, for example, Mo, W, Nb, Ta, Ti, Zr, or an alloy thereof, but is not limited thereto. Moreover, the thickness of the bulk body 1 used as the sputtering target material formed by this invention can be changed suitably, and is 2 mm-20 mm, More preferably, it is 5-15 mm.
The base 2 applied in the present invention is expensive because it has the same composition as the sputtering target, so the thinner the better, but the base 2 is difficult to handle when the thickness of the base 2 is less than 0.1 mm. become. For this reason, in this invention, the thickness of the base | substrate 2 shall be 0.1 mm or more.
On the other hand, if the substrate 2 is thicker than 2.0 mm, the substrate 2 itself functions as a bulk body. Therefore, it departs from the gist of the present invention of forming a bulk body by depositing particles, and is manufactured by a physical deposition method. The merit of the method is not obtained. For this reason, in this invention, the thickness of the base | substrate 2 shall be 2.0 mm or less.
When a thermal spraying method is applied to the formation of the bulk body 1, it is preferable to form irregularities on the surface of the substrate 2 on which the bulk body 1 is deposited by shot blasting or the like. This is for securing the adhesion between the bulk body 1 and the substrate 2 by the anchor effect. Further, when the cold spray method is applied to the formation of the bulk body 1, the surface roughness of the surface of the substrate 2 on which the bulk body 1 is deposited is not particularly limited, and a commercially available plate material or the like can be used.

In the present invention, when deformation of the base 2 is expected due to the influence of a gas flow colliding with the surface of the base 2 together with the particles 3, the support 4 is disposed on the back surface of the base 2 as shown in FIG. Is preferred. Thereby, this invention can prevent the deformation | transformation of the base | substrate 2 when forming the bulk body 1. FIG. In addition, since this support body 4 does not need to consider the problem of the thermal expansion difference mentioned above by arrange | positioning on the back surface of the base | substrate 2, even if it does not join to the base | substrate 2, the material which can suppress a deformation | transformation of the base | substrate 2 is possible. If it is, it will not be specifically limited.
In the present invention, it is preferable to form the bulk body 1 in an inert gas atmosphere. The present invention can prevent the sputtering target material from being deteriorated by forming the bulk body 1 in an atmosphere-replaced chamber or in an atmosphere that does not come into contact with a reactive gas such as oxygen in a shield gas or the like.

In the present invention, it is preferable to perform a heat treatment for releasing the residual compressive stress as a post-treatment on the sputtering target material in which the bulk body 1 is formed on the substrate 2. Thereby, this invention can also suppress the deformation | transformation and peeling by the impact at the time of sputtering.
In the present invention, as a post-treatment, it is preferable to perform a maintenance process such as polishing on the sputter surface and side surfaces of the bulk body 1 by machining. Thereby, it can be set as the sputtering target material which has the target shape and dimension.
The sputtering target material obtained by integrating the bulk body 1 and the substrate 2 obtained as described above is machined to a predetermined product size, and then joined by a backing plate or a backing tube and a brazing material, etc. Complete as a target.

Using a plasma spraying apparatus, argon gas (main gas) and helium gas (auxiliary gas) are used as the working gas, and a molten Mo powder is deposited on a Mo substrate having a thickness of 1 mm in an air atmosphere. A 5 mm thick Mo bulk was formed.
As a result, as shown in FIG. 2, it was confirmed that a Mo bulk body having a porosity of 10% could be formed on the Mo base, and there was no separation between the base body and the bulk body.

Using a cold spray device (PCS-1000 manufactured by Plasma Giken Kogyo Co., Ltd.), Mo powder having an average particle size of 9 μm was collided and deposited on a Mo substrate having a thickness of 1 mm to form a Mo bulk body having a thickness of 3 mm. . The bulk body was formed by using helium gas as a working gas, a gas pressure of 3 MPa, and a gas temperature of 1000 ° C.
As a result, as shown in FIG. 3, it was confirmed that a dense Mo bulk body having a porosity of 1% or less could be formed on the Mo base, and that there was no separation between the base and the bulk body.
As a comparative example, Mo powder was collided and deposited on a 3 mm thick SUS substrate under the same cold spray conditions as in the present invention example to form a 2.5 mm bulk body.
As a result, a dense bulk body similar to that in Example 1 could be formed, but as shown in FIG. 4, during cooling after cold spraying, cracks entered the Mo bulk body from the end face and were peeled off from the substrate. It was confirmed.

DESCRIPTION OF SYMBOLS 1 Bulk body 2 Base body 3 Particle | grain 4 Support body

Claims (1)

  A method for producing a sputtering target material, wherein a bulk body is formed by directly depositing particles having the same composition as a substrate on a substrate having a thickness of 0.1 to 2.0 mm.