WO2021177152A1

WO2021177152A1 - Cylindrical sputtering target and method for producing same

Info

Publication number: WO2021177152A1
Application number: PCT/JP2021/007262
Authority: WO
Inventors: 晋岡野; 和泰西村
Original assignee: 三菱マテリアル株式会社
Priority date: 2020-03-04
Filing date: 2021-02-26
Publication date: 2021-09-10

Abstract

The present invention is configured by spacers (4) being interposed in a gap between a backing tube (3) and a target (2) that has a bending strength of 350 MPa or less, and a bonding part (5) being formed for establishing a bonded state between the target (2) and the backing tube (3). The target (2) is constituted by a plurality of separate targets (2a) lined up in series. Three or more spacers (4) are provided along the length direction of the separate targets (2a) and with an interval in the circumferential direction, in the gap between the separate target(s) (2a) arranged at at least one end and the backing tube (3), the spacers having the length between 0.2 to 0.8 times the length of the separate targets (2a), and the total of the cross-sectional area being between 0.0034 to 0.006 times the cross-sectional area of the gap.

Description

Cylindrical sputtering target and its manufacturing method

The present invention relates to a cylindrical sputtering target used in a sputtering apparatus and a method for manufacturing the same.
This application claims priority based on Japanese Patent Application No. 2020-036760 filed in Japan on March 4, 2020 and Japanese Patent Application No. 2021-216221 filed in Japan on February 15, 2021. Is used here.

A sputtering device that performs sputtering while rotating a cylindrical sputtering target is known. In the cylindrical sputtering target used in this type of sputtering apparatus, the inner peripheral surface of the cylindrical target is joined to the outer peripheral surface of the cylindrical backing tube. Further, in general, a spacer is provided in the gap in order to keep the gap between the backing tube and the target constant.

In this case, in this type of cylindrical sputtering target, the backing tube is made of metal such as SUS from the viewpoint of mechanical strength. On the other hand, when a metal having low bending strength or an oxide-based or non-oxide-based (carbide, nitride, etc.) ceramic is used as the target, the target cracks due to the difference in thermal expansion from the backing tube. May occur.

Patent Document 1 describes an inner surface of a cylindrical target material in a cylindrical sputtering target formed by joining a plurality of cylindrical target materials made of a cylindrical ceramic sintered body to an outer surface of a backing tube (cylindrical base material). It is described that a plurality of spacers thinner than the thickness of the clearance are provided in the clearance formed by the outer surface of the cylindrical base material. For example, six copper wires are used as spacers. Further, it is described that the thickness of the spacer is preferably about 80% of the thickness of the clearance in order to achieve both the accuracy of centering and workability.

Patent Document 2 also describes that the thickness of the spacer inserted in the clearance between the target material and the backing tube (base material) is preferably about 80% of the clearance. It is described that by doing so, strain due to thermal expansion or the like in the joining process is alleviated and cracks and cracks are prevented from occurring.

Japanese Patent Application Laid-Open No. 2011-252237 (A) Japanese Patent Application Laid-Open No. 2005-282862 (A)

In these patent documents, the thickness of the spacer is regulated to prevent the occurrence of cracks in the target, but further improvement is desired.

The present invention has been made in view of such circumstances, and in a cylindrical sputtering target using a cylindrical target made of metal or ceramics having low bending strength, the gap between the target and the backing tube is constant. It is an object of the present invention to provide a cylindrical sputtering target capable of preventing cracks from being generated in the target while holding the target, and a method for manufacturing the same.

The cylindrical sputtering target of one aspect of the present invention (hereinafter, referred to as “cylindrical sputtering target of the present invention”) is arranged in a cylindrical target having a bending strength of 350 MPa or less and an inserted state in the target. A spacer is interposed in the gap between the cylindrical backing tube and a joint portion is formed in which the inner peripheral surface of the target and the outer peripheral surface of the backing tube are in a bonded state.
The target is configured by arranging a plurality of divided targets in series.
Three or more spacers are provided in the gap between the split target arranged at at least one end of the target and the backing tube along the length direction of the split target and at intervals in the circumferential direction. Ori,
The length of the spacer is 0.2 times or more and 0.8 times or less with respect to the length of the divided target, and the total cross-sectional area of the spacer is 0.0034 times or more with respect to the cross-sectional area of the gap. It is 0.006 times or less.

By interposing three or more spacers in the gap between the target and the backing tube at the above dimensional ratio, the target is pressed from the inside by reducing the gap due to the difference in thermal expansion between the target and the backing tube. Even if it is done, it is possible to prevent the target from being cracked. If the length of the spacer is less than 0.2 times the length of the split target, misalignment between the target and the backing tube is likely to occur, and if it exceeds 0.8 times, a wide range of the length of the split target due to the difference in thermal expansion. Since the pressing force acts on the target, cracks may occur in the target. If the total cross-sectional area of the spacer is less than 0.0034 times the cross-sectional area of the gap, misalignment between the target and the backing tube is likely to occur, and if it exceeds 0.006 times, cracks are likely to occur in the target.

The present invention is particularly effective in a cylindrical target having a low bending strength of 350 MPa or less because cracks may occur due to the difference in thermal expansion from the backing tube as described above.
As the shape of the spacer, a linear shape such as a wire is preferable, but the cross section thereof does not necessarily have to be circular, and a rectangular shape or the like can also be adopted.

In this cylindrical sputtering target, the radial dimension of the spacer is preferably 0.6 times or more and 0.9 times or less with respect to the radial dimension of the gap. With this dimensional relationship, it is possible to more reliably prevent the occurrence of misalignment and cracks in the target.

In this cylindrical sputtering target, the spacer may be made of aluminum or an aluminum alloy.
Since aluminum or an aluminum alloy has appropriate hardness and thermal conductivity and is easily available and processed, a cylindrical sputtering target can be manufactured at low cost.

In the method for producing a cylindrical sputtering target according to another aspect of the present invention (hereinafter, referred to as "the method for producing a cylindrical sputtering target of the present invention"), a plurality of cylindrical targets having a bending strength of 350 MPa or less are divided. The split target is constructed by arranging the targets, and a cylindrical backing tube is placed in the target in an inserted state, and the split target is placed in a gap between the split target placed at at least one end of the target and the backing tube. By interposing three or more spacers having a length of 0.2 times or more and 0.8 times or less with respect to the length along the length direction of the split target and at intervals in the circumferential direction, these spacers are used. The total cross-sectional area of the above is set to 0.0034 times or more and 0.006 times or less with respect to the cross-sectional area of the gap, and the welded material in a molten state is filled in the gap and solidified.

According to the cylindrical sputtering target of the present invention, it is possible to prevent cracks from occurring in the target, maintain a constant gap between the target and the backing tube, and prevent melting of the bonding material during sputtering. can.

It is a vertical sectional view which shows the cylindrical sputtering target of an embodiment. It is a cross-sectional view at the spacer arrangement position of FIG. It is a flowchart which shows the manufacturing method of an embodiment. It is a vertical cross-sectional view of a state in which a part of a backing tube is inserted into a target on a cradle. FIG. 5 is a vertical cross-sectional view showing a state in which the backing tube is lowered from the state shown in FIG. 4 and the space between the target and the backing tube is filled with the bonding material. It is a cross-sectional view similar to FIG. 2 showing another example of the arrangement of spacers.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The cylindrical sputtering target 1 of one embodiment is, for example, as shown in FIGS. 1 and 2, a cylindrical backing tube (hereinafter referred to as a backing tube) 3 in a cylindrical target (hereinafter referred to as a target) 2. Is inserted. In this case, the target 2 and the backing tube 3 are arranged so that the central axes C coincide with each other, and a spacer 4 is provided in the gap between the target 2 and the backing tube 3 and is held by the spacer 4. A joint portion 5 for joining the inner peripheral surface of the target 2 and the outer peripheral surface of the backing tube 3 is formed in the space (see FIG. 4).

The target 2 of the present embodiment is a metal, oxide-based or non-oxide-based (carboide, nitride, etc.) ceramic having low bending strength, for example, CuGa, ITO (In ₂ O _3- _{SnO 2} ), AZO (Al _2). O _3- ZnO), SIZ (SiO _2-In ₂ O ₃ _{-ZrO 2} ), IGZO (InGaZnO ₄ ), CUCUO (Cu-CuO), Al ₂ O ₃ , SiO ₂ , GaN, SiC, etc., with an inner diameter of 120 mm or more. It is formed into a tubular member having a diameter of 140 mm, an outer diameter of 150 mm to 170 mm, and a length of 0.4 m to 3.9 m. The bending strength of the target 2 is 350 MPa or less. Regarding the bending strength, a plate with a thickness of 3 mm, a width of 4 mm, and a length of 40 mm was prepared from each material constituting the target 2, and the bending strength at three points was measured based on the JIS R1601 standard, and the bending strength was measured. It was made strong.

Further, since the target 2 has a long length in the axial direction of the central axis C with respect to its outer diameter, it is divided into a plurality of targets in the length direction (longitudinal direction) to have a short length. It is configured by arranging a plurality of division targets 2a in series. In the illustrated example, it is composed of three divided targets 2a, but more divided targets, for example, about 12 divided targets 2a may be arranged side by side depending on the required length of the target 2.

The backing tube 3 is formed in a single tubular shape longer than the target 2. For example, a tubular member having an outer diameter of 119 mm to 139 mm and a length of 0.5 m to 4 m and made of titanium, stainless steel, or copper or a copper alloy can be used.
With the backing tube 3 inserted in the target 2, between the inner peripheral surface of the target 2 and the outer peripheral surface of the backing tube 3 is 0.5 mm to 1 mm (radial dimension) in the radial direction about the central axis C. A gap g (see FIG. 4) of d0) is formed, a plurality of spacers 4 are inserted into the gap g, and the joint material is filled and solidified in the space held by the spacer 4, so that the joint portion 5 is formed. Is formed.

For the spacer 4, it is preferable to use a material having a Vickers hardness of 60 Hv or less and a thermal conductivity of 100 W / (m · K) or more. For example, aluminum or aluminum alloy, copper or copper alloy, stainless steel, zinc, silver, gold and the like can be used. Among these, aluminum or an aluminum alloy is suitable because it has appropriate hardness and thermal conductivity. Further, as the shape of the spacer 4, a sheet-like (plate-like) shape is used in addition to a linear or rod-like shape such as a wire as long as it fits within the gap g between the target 2 and the backing tube 3. be able to.

Further, the spacer 4 is provided only between the split targets 2a arranged at both ends and the backing tube 3 among the split targets 2a arranged in series, and is between the split target 2a and the backing tube 3 in the intermediate portion. Is not provided in. Since the backing tube 3 is long, the dimensional accuracy of straightness tends to vary due to undulations and the like. Therefore, spacers 4 are arranged only at both ends so that dimensional errors in the intermediate portion can be absorbed.

The length L1 of the spacer 4 (the length arranged in the split target 2a) is 0.2 times or more and 0.8 times or less with respect to the length L0 of the split target 2a. If the length L1 of the spacer 4 is less than 0.2 times the length L0 of the split target 2a, misalignment between the target 2 and the backing tube 3 is likely to occur, and if it exceeds 0.8 times, the split target is divided due to the difference in thermal expansion. Since the pressing force acts in a wide range of the length L1 of 2a, there is a possibility that a crack may occur in the split target 2a.

Further, a plurality of spacers 4 are provided in the gap g between the target 2 and the backing tube 3 at intervals in the circumferential direction (in this case, the outer peripheral direction of the backing tube or the inner peripheral direction of the target). In the illustrated example, four spacers 4 are provided at equal intervals, but a plurality of spacers (for example, about 3 or more and about 15) may be provided. The total cross-sectional area of these four spacers 4 is set to 0.0034 times or more and 0.006 times or less the cross-sectional area of the gap g between the target 2 and the backing tube 3. If the total cross-sectional area of the spacer 4 is less than 0.0034 times the cross-sectional area of the gap g, the target 2 and the backing tube 3 are likely to be misaligned, and if it exceeds 0.006 times, the target 2 is likely to be cracked.

Further, in the inserted state in which the spacer 4 is arranged in the gap g between the target 2 and the backing tube 3, the radial dimension d1 of the spacer 4 is relative to the radial dimension d0 of the gap g between the target 2 and the backing tube 3. It is preferably 0.6 times or more and 0.9 times or less. With this dimensional relationship, it is possible to more reliably prevent misalignment and cracks in the target 2. The radial dimension d1 of the spacer 4 and the radial dimension d0 of the gap g mean the radial size of the cylindrical sputtering target 1 as shown in FIG.

The bonding material constituting the bonding portion 5 is, for example, an indium alloy having an indium content of 60% by mass or more (for example, In—Sn alloy, In—Bi alloy, In—Zn alloy) or pure indium, having a tin content of 60% by mass. The above tin alloy, pure tin, etc. are used. This joining material is left in a molten state, and with the backing tube 3 inserted inside the target 2, the space between the target 2 and the backing tube 3 held by the spacer 4 is filled and solidified.

A method for manufacturing the cylindrical sputtering target 1 configured as described above will be described.
In this cylindrical sputtering target 1, the backing tube 3 is inserted inside the target 2, and the spacer 4 is interposed in the gap g formed by the insertion, and the space held by the spacer 4 is filled with the bonding material. It is manufactured by solidifying it. In this case, there are the following two methods for filling the space between the target 2 held by the spacer 4 and the backing tube 3 with the bonding material.

(1) A method in which the backing tubes 3 are inserted inside the target 2 so that they are arranged coaxially in a vertical position, and the molten joint material is filled from above the space held by the spacer 4 (2) Target. A recess was formed on the table on which 2 was placed vertically so as to be arranged inside the target 3, and the bonded material in a molten state was stored in this recess, and the lower end was closed inside the target 2. A method of inserting the backing tube 3 and filling the space held by the spacer 4 from below while pushing the joint material in the recess by the lower end portion of the backing tube 3.

In the following embodiment, it will be described as filling the joint material by the method (2).
Specifically, as shown in the flowchart of FIG. 3, the backing tube 3 and the target 2 are heated, the base treatment step using the base treatment bonding material, and the backing tube 3 is inserted into the vertically held target 2 from the lower end portion. , Partial assembly process of assembling halfway in a state where a space held by a spacer 4 is formed between them, reheating process of target 2 and backing tube 3, and assembly of target 2 and backing tube 3 assembled halfway. While continuing, the joining material filling step and the cooling step of filling the space held by the spacer 4 with the filling joining material are performed in this order. Hereinafter, the steps will be described in order.

(Heating process)
Each of the divided targets 2a and the backing tube 3 is heated, and the inner peripheral surface of each divided target 2a and the outer peripheral surface of the backing tube 3 which are the joining surfaces thereof are equal to or higher than the melting point (or liquidus temperature) of the base treatment bonding material described later. Heat to the temperature of.

(Base treatment process)
In the heating step, the base-treated bonding material in the molten state is applied to the inner peripheral surface of each of the divided targets 2a in the heated state and the outer peripheral surface of the backing tube 3. The base-treated joint material may be the same material as the joint material filled in the space between the target 2 and the backing tube 3, and among the above-mentioned joint materials, the joint material filled in the space is You may choose different combinations.
In this case, by applying the base treatment bonding material while applying ultrasonic vibration with an ultrasonic soldering iron (not shown) equipped with a heater, dirt and oxidation on the inner peripheral surface of the split target 2a and the outer peripheral surface of the backing tube 3 The removal of the film is promoted, and the surface-treated bonding material is applied to these surfaces.
At this time, spacers 4 are arranged at both ends of the outer peripheral surface of the backing tube 3 and fixed with adhesive tape or the like so as not to move. In the illustrated example, four spacers 4 are provided (see FIG. 2). The position where the spacer 4 is fixed is a position where the ends of the split targets 2a at both ends of the split targets 2a arranged in series are arranged in a later assembly step.

(Partial assembly process)
The division targets 2a are vertically stacked on the mounting table 10 shown in FIG. A recess 11 having an inner diameter substantially the same as the inner diameter of the target 2 is provided on the surface of the mounting table 10, and the target 2 is arranged so as to surround the recess 11. At this time, the central axes of the divided targets 2a are aligned with each other. On the other hand, the lower end of the backing tube 3 is closed with a stopper 12 to prevent the joining material from entering the backing tube 3.
Further, an annular packing 13 made of a resin such as PTFE (polytetrafluoroethylene) is interposed between the split targets 2a connected vertically and between the upper surface of the mounting table 10 and the lowermost split target 2a. At the upper end of the target 2, a dam portion 14 for receiving the molten bonding material 50 overflowing from the space between the target 2 and the backing tube 3 is formed.

Then, the backing tube 3 is inserted into the target 2 from above the stacked split targets 2a, and as shown in FIG. 4, the backing tube 3 is inserted up to about 80% of the total length of the backing tube 3. At the time of this insertion, spacers 4 are provided on the outer peripheral surfaces of both ends of the backing tube 3 at equal intervals in the circumferential direction, so that the backing tube 3 is aligned on the axis C of the target 2.

(Reheating process)
The recess 11 of the mounting table 10 is filled with the bonding material 50 to keep it in a molten state.
Further, as shown in FIG. 4, the target 2 and the backing tube 3 in a state where about 80% of the total length is inserted are heated by a heater (not shown) arranged around the target 2. By this heating, the base-treated bonding material applied to the inner peripheral surface of the target 2 and the outer peripheral surface of the backing tube 3 is melted or at least semi-melted.

(Joint material filling process)
Next, as shown by an arrow in FIG. 4, when the lower end of the backing tube 3 is inserted into the recess 11 of the mounting table 10, the target is pushed out from the recess 11 as shown in FIG. The space between the inner peripheral surface of 2 and the outer peripheral surface of the backing tube 3 is raised, and the bonding material 50 is filled between the inner peripheral surface of the target 2 and the outer peripheral surface of the backing tube 3 and applied as a base. It is filled in the space together with the joining material.

The volume of the recess 11 of the mounting table 10 is set within the space formed between the outer peripheral surface of the backing tube 3 and the inner peripheral surface of the target 2 when the lower end of the backing tube 3 is inserted close to the bottom surface. The amount of the joining material 50 that is pushed up may be set to be equal to or larger than the volume of the gap g, and the joining material 50 that has risen in the space may slightly overflow to the upper end side of the target 2.
In this case, it can be confirmed that the joining material 50 is filled between the target 2 and the backing tube 3 without a gap in a state where the joining material 50 overflows the dam portion 14 at the upper end of the target 2.

By inserting the lower end of the backing tube 3 to the vicinity of the bottom surface of the recess 11 in this way, the bonding material 50 is filled in the space between the target 2 and the backing tube 3 without a gap.
Although not necessarily limited, the above-mentioned reheating step and the joining material filling step (at least until the filling is completed) are performed in an inert atmosphere such as argon or nitrogen in order to prevent oxidation of the joining material. It is good to carry out.

(Cooling process)
After filling the space between the target 2 and the backing tube 3 with the bonding material 50, the target 2 and the backing tube 3 are integrated by the joint portion 5 by cooling and solidifying the bonding material 50.
After that, the annular packing 13, the dam portion 14, the protruding joint material, and the like are removed and cleaned to obtain the cylindrical sputtering target 1. In the cylindrical sputtering target 1, the joint portion 5 between the backing tube 3 and the target 2 is formed by the spacer 4 to have a uniform thickness in the circumferential direction.

In this final assembly form, the spacer 4 starts from the tip of the split target 2a arranged at both ends of the target 2 (the upper end in the uppermost split target 2a in FIG. 5 and the lower end in the lowermost split target 2a). It is provided in a state of being inserted inside. Therefore, the spacer 4 exists in a range of 0.2 times or more and 0.8 times the length L0 of the divided target 2a from the upper end or the lower end of the divided target 2a. Further, in the example shown in FIG. 5, the end portion of the spacer 4 at the lower end portion is provided so as to protrude from the tip end of the split target 2a. After the joint portion 5 is formed, the end portion of the spacer 4 that protrudes is cut off.

In the cylindrical sputtering target 1 manufactured in this manner, since a plurality of spacers 4 are arranged at equal intervals in the gap g between the target 2 and the backing tube 3, the target 2 and the backing tube 3 are coaxially arranged. It is arranged so that sputtering can be made uniform while rotating.

Further, the spacer 4 has a length L1 that is 0.2 times or more and 0.8 times the length L0 of the split target 2a, and the total cross-sectional area of the spacer 4 (for example, of the four spacers 4). Since the total cross-sectional area) is set to 0.0034 times or more and 0.006 times or less of the cross-sectional area of the gap g, it is caused by the difference in thermal expansion between the target 2 and the backing tube 3 due to heating and cooling during manufacturing. Even when the target 2 is in a tightly fitted state (a state in which the gap g becomes small), cracks are prevented from occurring in the target 2. In this case, if the length L1 of the spacer 4 is less than 0.2 times the length L0 of the split target 2a, misalignment between the target 2 and the backing tube 3 is likely to occur, and if it exceeds 0.8 times, the difference in thermal expansion As a result, the pressing force acts in a wide range of the length of the split target 2a, so that the target 2 may be cracked. If the cross-sectional area of the spacer 4 is less than 0.0034 times the gap g, the target 2 and the backing tube 3 are likely to be misaligned, and if it exceeds 0.006 times, the target 2 is likely to be cracked.

Further, since the diameter d1 of the spacer 4 (dimension along the radial direction of the target 2) d1 is set to 0.6 times or more and 0.9 times or less with respect to the radial dimension d0 of the gap g between the target 2 and the backing tube 3. , It is possible to more reliably prevent the occurrence of misalignment and cracks in the target 2.

In the above-described embodiment, an example in which the number of spacers 4 is four is shown, but at least three spacers may be used. Further, although these plurality of spacers 4 are provided in the gap g at equal intervals in the circumferential direction, they do not have to be at equal intervals.
When a plurality of spacers 4 are provided, if the spacers 4 are arranged at both positions facing each other at 180 °, the target 2 is pressed on both sides in the radial direction by both of the spacers 4 during thermal expansion and contraction. In order to avoid this, as in the sputtering target 11 shown in FIG. 6, each spacer 4 is arranged at a position avoiding the 180 ° facing position of the target 2 (two of the four spacers). The position in the 180 ° facing direction with respect to the spacer 4 is indicated by P), and the space between the target 2 and the backing tube 3 remains the same size at the 180 ° facing position where the spacer 4 is provided. Since it is arranged in, the difference in thermal expansion and contraction can be absorbed in the space portion, and the occurrence of cracks can be effectively prevented. In particular, when an even number of spacers 4 are arranged, if they are evenly spaced, they are arranged at 180 ° facing positions, so it is preferable to arrange them slightly offset so as to avoid this.

Further, in the above-described embodiment, the base-treated bonding material is applied to both the target 2 and the backing tube 3, but if the surfaces thereof are in a state of being easily wetted with the bonding material 50, the surface of the surface is coated with the surface-treated bonding material. May be omitted.
Further, although the spacers 4 are arranged between the two split targets 2a arranged at both ends of the target 2 and the backing tube 3, if they are arranged between the split target 2a at at least one end and the backing tube 3. good.
Further, the split targets 2a do not necessarily all have the same length. Even in that case, the ratio of the length L1 of the spacer 4 to the length L0 of the split target 2a at the end portion where the spacer 4 is interposed may be 0.2 times or more and 0.8 times or less.

An experiment was conducted to confirm the effect of the present invention. A cylindrical sputtering target was prepared by the method described in the embodiment using various targets, backing tubes, and spacers shown in Table 1. In the table, "TG" refers to the target and "BT" refers to the backing tube. Also, of the target material, the one shown by _{_{_{_{abbreviations, SIZ (SiO 2 -In 2 O}}}} 3 -ZrO 2), IGZO (InGaZnO 4), CUCUO (Cu-CuO), ITO (In 2 O 3 -SnO 2) Is. All of these targets have a bending strength of 350 MPa or less. A metal wire having a circular cross section was used as the spacer, and the spacers were arranged at equal intervals in the circumferential direction. An In-48.0 mass% Sn alloy was used as the bonding material.

After joining, the mixture was cooled to room temperature, and the presence or absence of misalignment and the presence or absence of cracks in the target were evaluated.
The presence or absence of misalignment is determined by the radial distance from the outer peripheral surface of the target to the outer peripheral surface of the backing tube at both ends of the target at four points at 90 ° intervals based on any of the places where the spacers are arranged. Each was measured, and the absolute value of the difference in distance between the two points facing each other by 180 ° (| X1-X2 | in FIG. 2) was obtained. The average value of the difference in distance (| X1-X2 |) is calculated, and the average value is 0.8 of the radial dimension d0 ((TG inner diameter-BT outer diameter) / 2) of the gap g between the target and the backing tube. If it is twice or less, it is A, if it is more than 0.8 times and 1.0 times or less, it is B, and if it is larger than the radial dimension d0 of the gap g, it is C. If the gap is g or less, it is considered as a pass.
Regarding the presence or absence of cracks, those in which cracks having a length of 1 mm or more were observed were rated as “presence”, and those in which no cracks were observed were rated as “absent”.
These results are shown in Tables 1 and 2. In Table 2, "diameter / gap" is the value of the radial dimension d0 of the spacer diameter / gap g, and "cross-sectional area ratio" is the value of the total cross-sectional area of the spacer / the cross-sectional area of the gap g. For the “point ratio”, the value of the length L1 of the spacer and the length L0 of the split target 2a is described.

As shown in Tables 1 and 2, in the sputtering targets of the examples, no cracks were observed in the targets, and no large misalignment was observed.

On the other hand, in Comparative Examples 1 and 2, the total cross-sectional area of the spacer was 0.0073 times and 0.0072 times larger than the cross-sectional area of the gap, so that the target cracked. In Comparative Examples 3 and 4, on the contrary, the cross-sectional area ratios were as small as 0.0030 times and 0.0027 times, so that the misalignment became large. In Comparative Example 5, the ratio of the length of the spacer to the length of the split target was small, so that the position was displaced. On the contrary, in Comparative Examples 6 to 9, since the length ratio of the spacers was large, cracks were observed in the target.

From these results, three or more spacers are provided in the gap between the target and the backing tube, the length of the spacer is 0.2 times or more and 0.8 times or less of the length of the divided target, and the cross-sectional area of the spacer is It can be seen that when the total is 0.0034 times or more and 0.006 times or less with respect to the cross-sectional area of the gap, no cracking of the target or large misalignment is observed, and a good sputtering target can be manufactured. In that case, if the ratio of the spacer diameter d1 to the radial dimension d0 of the gap is 0.6 times or more and 0.9 times or less, the misalignment can be further reduced.

1 Cylindrical sputtering target 2 Target 2a Divided target 3 Backing tube 4 Spacer 5 Joint part 50 Molten joint material 10 Mounting stand 11 Recession 12 Plug 13 Circular packing 14 Dam part C Central axis

Claims

A spacer is interposed in the gap between the cylindrical target having a bending strength of 350 MPa or less and the cylindrical backing tube arranged in the target in the inserted state, and the inner peripheral surface of the target and the outer circumference of the backing tube. A joint is formed between the surface and the surface.
The target is configured by arranging a plurality of divided targets in series.
Three or more spacers are provided in the gap between the split target arranged at at least one end of the target and the backing tube along the length direction of the split target and at intervals in the circumferential direction. Ori,
The length of the spacer is 0.2 times or more and 0.8 times or less with respect to the length of the divided target, and the total cross-sectional area of the spacer is 0.0034 times or more with respect to the cross-sectional area of the gap. A cylindrical sputtering target characterized by being 0.006 times or less.
The cylindrical sputtering target according to claim 1, wherein the radial dimension of the spacer is 0.6 times or more and 0.9 times or less with respect to the radial dimension of the gap.
The cylindrical sputtering target according to claim 1 or 2, wherein the spacer is made of aluminum or an aluminum alloy.
A cylindrical target having a bending resistance of 350 MPa or less is constructed by arranging a plurality of divided targets, and a cylindrical backing tube is placed in the target in an inserted state and placed at at least one end of the target. In the gap between the split target and the backing tube, a spacer having a length of 0.2 times or more and 0.8 times or less the length of the split target is placed along the length direction of the split target and around the circumference. By interposing three or more spacers at intervals in the direction, the total cross-sectional area of these spacers is set to 0.0034 times or more and 0.006 times or less with respect to the cross-sectional area of the gap, and melts in the gap. A method for manufacturing a cylindrical sputtering target, which comprises filling and solidifying a state-bonded material.