JP6768606B2 - Manufacturing method of cylindrical sputtering target - Google Patents

Description

The present invention relates to a method for manufacturing a cylindrical sputtering target used for sputtering by a magnetron type rotary cathode sputtering apparatus.

Conventionally, as a sputtering target, a flat plate type sputtering target in which a flat plate type target material is bonded to a backing plate has been generally used. When sputtering is performed by the magnetron sputtering method using a flat plate sputtering target, the utilization efficiency of the target material remains at 20% to 30%. The reason is that in the magnetron sputtering method, plasma is concentrated and collided with a specific part of the target material by a magnetic field, so that a phenomenon that erosion progresses to a specific part of the surface of the target material occurs, and the deepest part of the target material is This is because the life of the target material will be reached when the backing plate is reached.

To solve this problem, it has been proposed to improve the efficiency of using the target material by making the shape of the sputtering target cylindrical. This method uses a cylindrical sputtering target composed of a cylindrical backing tube and a cylindrical target material formed on the outer periphery thereof, and a magnetic field generation facility and a cooling facility are installed inside the backing tube to form a cylinder. Shape Sputtering is performed while rotating the target. It is said that this method can increase the efficiency of use of the target material to 60% to 70%.

As a target material for a cylindrical sputtering target, a metal material that is easy to process into a cylindrical shape and has high mechanical strength is widely used, but a ceramic material has low mechanical strength and is brittle. It has not yet become widespread.

Currently, the method for manufacturing a cylindrical ceramics sputtering target is to form a cylindrical ceramics molded body by cold hydrostatic pressing (CIP) and sinter it to obtain a cylindrical ceramics sintered body. It has gained. In this manufacturing method, it is common to form a cylindrical sputtering target by bonding (bonding) a cylindrical ceramics sintered body with a backing tube and a bonding material.

In the method for manufacturing a cylindrical sputtering target, a backing tube made of a metal such as austenitic stainless steel or titanium is usually used. The clearance between the cylindrical target material and the backing tube is usually 1.5 mm or less, and it is important to maintain this clearance evenly and fill the joint material without gaps.

For example, Patent Document 1 discloses a method in which cylindrical target materials are vertically stacked and a plurality of spacers are provided in the clearance generated between the cylindrical target materials to maintain the clearance evenly and the bonding material is poured. Further, in Patent Document 2, a cylindrical target material is fixed on a storage tank of a molten material, spacers are attached to the backing tube so as to cover both ends of the target material, and a dummy plug is further attached to one end of the backing tube. Then, the backing tube is lowered into the storage tank of the bonding material to fill the clearance with the bonding material.

Japanese Unexamined Patent Publication No. 2011-252237 Japanese Unexamined Patent Publication No. 2014-037619

However, in the manufacturing methods of Patent Document 1 and Patent Document 2, an unfilled portion is generated in the clearance between the target material and the backing tube due to volume shrinkage due to cooling of the molten bonding material, so that the bonding material filled in this clearance is filled. The joining rate will be low. In the cylindrical sputtering target produced by these manufacturing methods, the bonding ratio of the bonding material filled in the clearance is lowered, so that the thermal conductivity of the bonding layer is low. As a result, the cooling effect due to the passage of water inside the backing tube is reduced, so that it may not be possible to apply high power as in the magnetron sputtering method.

Further, in the clearance between the target material and the backing tube, a plurality of spacers for maintaining the clearance are still arranged together with the joining material. Since the spacer is installed on a curved surface with a narrow clearance, although it depends on the shape, voids are likely to occur at the corners of the spacer and the contact portion with the curved surface when the joint material is filled. When sputtering is performed using a target in which the voids remain in the bonding layer, problems such as cracking and peeling may occur in the target material due to the heat load during sputtering. Further, as this spacer, a copper material or a stainless steel material having a high coefficient of thermal expansion is generally used, and an indium alloy is used as a bonding material. Therefore, there is a difference in the coefficient of thermal expansion between the part where only the bonding material is used and the part where there is a spacer, which causes cracking or chipping of the target. Further, since the portion where the spacer is provided is in contact with the backing tube and is not joined by the joining material, the target material and the backing tube are likely to be peeled off when the temperature becomes high.

As described above, it is desired that the clearance between the target material and the backing tube is filled with only the bonding material by a low-cost and simple method, and the bonding ratio of the bonding material filled in the clearance is improved.

Therefore, the present invention has been devised in view of the above-mentioned problems of the prior art, and the above-mentioned clearance is maintained while maintaining an even width of the clearance between the target material made of the cylindrical ceramic sintered body and the backing tube. It is an object of the present invention to provide a new and improved method for manufacturing a cylindrical sputtering target capable of improving the bonding ratio of the bonding material to be filled in.

That is, in one aspect of the present invention for achieving the above object, a cylindrical sputtering target is manufactured in which a molten bonding material is filled in a clearance between a target material made of a cylindrical ceramic sintered body and a cylindrical backing tube. In the method, a cylindrical dummy pipe is connected to the upper end surface of the target material, the backing tube is coaxially installed in the hollow portion of the target material, and a plurality of clearances between the dummy pipe and the backing tube are provided. A placement step of attaching the fixtures of the above at equal intervals in the circumferential direction, a filling step of filling the joint material in the clearance between the target material and the backing tube, and a cooling step of the joint material to cool the target material and the backing. It is characterized by having a joining step of joining with a tube.

Further, in one aspect of the present invention, the length of the fixture is preferably shorter than the length of the dummy pipe.

Further, in one aspect of the present invention, in the filling step, it is preferable to further fill the clearance between the dummy pipe and the backing tube to a predetermined height position of the dummy pipe.

Further, in one aspect of the present invention, after the arrangement step, a pressing step of fixing the target material is further provided, and in the pressing step, the upper end surface of the dummy pipe is pressed by the pressing mechanism to press the dummy pipe. It is preferable to fix the target material via.

Further, in one aspect of the present invention, in the arrangement step, it is preferable to attach the fixtures at four places at equal intervals in the circumferential direction in the clearance between the dummy pipe and the backing tube.

Further, in one aspect of the present invention, in the arrangement step, after connecting the dummy pipe to the upper end surface of the target material, the backing tube is coaxially installed in the hollow portion of the target material to and the dummy pipe. It is preferable to attach a plurality of fixtures at equal intervals in the circumferential direction in the clearance with the backing tube, or after the backing tube is coaxially installed in the hollow portion of the target material, it is placed on the upper end surface of the target material. It is preferable to connect the dummy pipes and attach a plurality of fixtures at equal intervals in the circumferential direction in the clearance between the dummy pipes and the backing tube.

According to the present invention, it is possible to improve the bonding ratio of the bonding material filled in the clearance while maintaining the clearance width between the target material made of the cylindrical ceramic sintered body and the backing tube evenly.

It is the schematic sectional drawing of the cylindrical sputtering target manufactured by the manufacturing method of the cylindrical sputtering target which concerns on one Embodiment of this invention. It is a flow chart which shows the outline of the manufacturing method of the cylindrical sputtering target which concerns on one Embodiment of this invention. (A) to (F) are sectional views schematically showing an outline of a method for manufacturing a cylindrical sputtering target according to an embodiment of the present invention. It is sectional drawing which shows the holding process included in the manufacturing method of the cylindrical sputtering target which concerns on one Embodiment of this invention. It is a schematic plan view which shows the 1st holding mechanism used in the manufacturing method of the cylindrical sputtering target which concerns on one Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. It should be noted that the present embodiment described below does not unreasonably limit the content of the present invention described in the claims, and all the configurations described in the present embodiment are essential as a means for solving the present invention. Is not always the case.

[1. Overview of Cylindrical Sputtering Target]
First, the configuration of the cylindrical sputtering target manufactured by the method for manufacturing the cylindrical sputtering target according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a cylindrical sputtering target manufactured by the method for manufacturing a cylindrical sputtering target according to an embodiment of the present invention.

As shown in FIG. 1, in the cylindrical sputtering target 1, a cylindrical target material 10 is installed on the outer peripheral surface of a cylindrical backing tube 20, and the target material 10 and the backing tube 20 are bonded to each other in a bonding layer 30. It is joined via. In the present embodiment, the cylindrical sputtering target 1 has a backing tube 20 coaxially arranged in a hollow portion on the inner peripheral surface side of the target material 10, and the central axes of the target material 10 and the backing tube 20 are aligned with each other. It is joined via a joining layer. That is, the cylindrical sputtering target 1 is formed by joining the inner peripheral surface of the target material 10 and the outer peripheral surface of the backing tube 20 so as to be integrated with each other via the bonding layer 30.

The size of the cylindrical sputtering target 1 can be appropriately adjusted according to the material, the customer's request, and the like, and is not particularly limited. For example, when a cylindrical ceramic sintered body having an outer diameter of 100 mm to 200 mm, an inner diameter of 80 mm to 180 mm, and a total length of 50 mm to 200 mm is used as the target material 10, when the target material 10 is used alone, it is divided. The size of the cylindrical sputtering target 1 is appropriately determined depending on the situation.

The target material 10 is made of a cylindrical ceramics sintered body, and the material of the cylindrical ceramics sintered body can be appropriately selected according to the intended use, and is not particularly limited. For example, oxidation containing at least one main component selected from indium (In), tin (Sn), zinc (Zn), aluminum (Al), niobium (Nb), tantalum (Ta), and titanium (Ti). A cylindrical ceramic sintered body composed of objects or the like can be used.

In particular, a cylindrical ceramics sintered body containing indium oxide as a main component, which is easily compatible with a low melting point bonding material described later, specifically, indium oxide (ITO) containing tin and indium oxide containing cerium (Ce) ( A cylindrical ceramic sintered body composed of ICO), indium oxide (IGO) containing gallium (Ga), indium oxide (IGZO) containing gallium and zinc, and the like is preferably used as the target material 10.

The outer diameter and the total length of the target material 10 can be appropriately adjusted according to the size of the cylindrical sputtering target. The inner diameter of the target material 10 can be appropriately adjusted according to the width of the clearance between the inner peripheral surface of the target material 10 and the outer peripheral surface of the backing tube 20 and the outer diameter of the backing tube, and these are particularly applicable. It is not limited. Further, as the target material 10, not only a material composed of one cylindrical ceramics sintered body but also a material obtained by connecting a plurality of cylindrical ceramics sintered bodies can be used. The method of connecting the cylindrical ceramic sintered bodies to each other is not particularly limited, and a known method can be used.

A base layer made of nickel or copper is formed on the inner peripheral surface of the target material 10 by plating or the like, or an ultrasonic soldering iron is used to wet the joint material so that it blends into the joint surface. Pretreatment may be performed.

The backing tube 20 has a thermal conductivity that can ensure sufficient cooling efficiency so that the bonding layer 30 does not deteriorate or melt when the material of the backing tube 20 is a cylindrical sputtering target 1, and is electrically conductive and cylindrical that can be discharged during sputtering. It suffices as long as it has enough strength to support the sputtering target 1. As the backing tube 20, for example, in addition to those made of general austenite-based stainless steel, especially SUS304, various materials such as copper or copper alloy, titanium or titanium alloy, molybdenum or molybdenum alloy, aluminum or aluminum alloy are used. be able to.

Further, the backing tube 20 can be subjected to a known surface treatment. For example, it is preferable to clean the surface of the backing tube 20 obtained by lathe processing or the like by blasting. By performing the blasting process in this way, it is possible to clean foreign substances and oils adhering to the lathe process and improve the wettability of the bonding material due to the increase in the specific surface area.

The total length of the backing tube 20 can be appropriately adjusted according to the size of the cylindrical sputtering target 1. The inner diameter can be appropriately adjusted according to the sputtering apparatus, and these are not particularly limited. Further, the outer diameter of the backing tube 20 is preferably set in consideration of the thickness of the base layer and the difference in the coefficient of linear expansion between the target material 10 and the backing tube 20.

For example, as the target material 10, ITO having a linear expansion coefficient at 20 ° C. of 7.2 × ^10-6 / ° C. is used, and as a backing tube, a linear expansion coefficient at 20 ° C. of 17.3 × ^10-6 / ° C. When a certain SUS304 is used, the backing tube has a clearance width of preferably 0.3 mm to 3.0 mm, more preferably 0.5 mm to 1.0 mm between the target material 10 and the backing tube 20. Set the outer diameter of 20.

If the clearance width between the target material 10 and the backing tube 20 is less than 0.3 mm, the backing tube 20 may thermally expand and the target material 10 may crack when the molten bonding material is injected into this gap. .. On the other hand, if the width of the gap exceeds 3.0 mm, it becomes difficult to arrange the backing tubes 20 coaxially in the hollow portion of the target material 10 and join them in a state where their central axes are aligned.

The bonding layer 30 is made of, for example, indium, and bonds the target material 10 and the backing tube 20. The role of the bonding layer 30 is to perform thermal transfer between the target material 10 and the backing tube 20 in order to dissipate the heat generated on the cylindrical sputtering target 1 by the electric discharge with the cooling liquid flowing inside the backing tube 20. It is in. That is, when the cylindrical sputtering target 1 is used, the bonding layer 30 may have thermal conductivity, electrical conductivity, adhesive strength, and the like in the same manner as the backing tube 20.

[2. Manufacturing method of cylindrical sputtering target]
Next, a method for manufacturing a cylindrical sputtering target according to an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a flow chart showing an outline of a method for manufacturing a cylindrical sputtering target according to an embodiment of the present invention. 3 (A) to 3 (F) are cross-sectional views schematically showing an outline of a method for manufacturing a cylindrical sputtering target according to an embodiment of the present invention. In the method for manufacturing a cylindrical sputtering target according to the present embodiment, a bonding material is filled in a clearance between a target material made of a cylindrical ceramic sintered body and a cylindrical backing tube. Then, as shown in FIG. 2, the present embodiment includes an arrangement step S1, a pressing step S2, a filling step S3, and a joining step S4. Hereinafter, each steps S1 to S4 will be described with reference to the drawings.

In the arranging step S1, a cylindrical dummy pipe is connected to the upper end surface of the target material, a backing tube is coaxially arranged in the hollow portion of the target material, and a plurality of fixtures are provided in the clearance between the dummy pipe and the backing tube. This is a process of mounting at equal intervals in the circumferential direction.

First, as shown in FIG. 3A, the dummy pipe 40 is connected to the upper end surface 11 of the target material 10 made of a cylindrical ceramic sintered body.

When the gap between the target material 10 and the backing tube 20 is filled with the joint material, the dummy pipe 40 is formed by the joint layer 30 up to the opening end above the clearance between the target material 10 and the backing tube 20. Even if the bonding material 31 is filled at a position higher than the upper end surface 11 of 10, the bonding material 31 has a function of blocking the bonding material 31 from leaking to the outside of the system.

The dummy pipe 40 is connected to the upper end surface 11 of the target material 10. In the filling step S3 of the subsequent step, by connecting the dummy pipes 40, when the target material 10 and the backing tube 20 are filled with the joining material 31, the dummy pipe 40 is located at a position higher than the upper end surface 11 of the target material 10. It is possible to fill the bonding material 31 up to a predetermined height. As a result, even if the bonding material 31 volume-shrinks during cooling to form the bonding layer 30, the position of the upper end surface of the bonding layer 30 is the same height as the upper end surface 11 of the target material 10. That is, the clearance between the target material 10 and the backing tube 20 can be filled with the bonding material 31 without filling the vicinity of the upper end surface 11 of the target material 10.

The dummy pipe 40 is made of Cu material or SUS material, and is not subjected to the above-mentioned pretreatment or the like. As a result, after forming the bonding layer 30 in the bonding step S4, the bonding material adhered to the dummy pipe 40 can be easily peeled off. The outer diameter and inner diameter of the dummy pipe 40 are set to be substantially the same as those of the target material 10. By making the shapes substantially the same, it can be treated in the same way as the target material. The length of the dummy pipe 40 is not particularly limited, but is made longer than the length of the fixture 60 when at least the fixture 60 (see FIG. 3C) is placed in the clearance between the dummy pipe and the backing tube. If the length of the dummy pipe 40 is shorter than the length of the fixture 60, such a fixture 60 remains within the clearance between the target material 10 and the backing tube 20. By making the length of the fixture 60 shorter than the length of the dummy pipe 40, the bonding layer 30 of the cylindrical sputtering target 1 can be filled with only the bonding material 31. Details will be described later.

The target material 10 and the dummy pipe 40 are arranged so that their central axes are the same with respect to the outer circumference or the inner circumference of each. The method of aligning the central axes is not particularly limited. For example, a reference pipe having substantially the same diameter as the target material 10 and the dummy pipe 40 may be used and arranged inside the target material 10 and the dummy pipe 40 to align the central axes. Further, the backing tube 20 may be utilized, and a plurality of spacers may be evenly inserted in the circumferential direction in the clearance between the backing tube 20, the target material 10 and the dummy pipe 40 to align the central axes. In this way, the target material 10 and the dummy pipe 40 are connected in a state where the central axes of the target material 10 and the dummy pipe 40 are aligned with each other. After connecting the target material 10 and the dummy pipe 40, the reference pipe and the spacer used for aligning the central axes are removed.

The means for connecting the target material 10 and the dummy pipe 40 is not particularly limited. For example, the outer circumference around the joint between the target material 10 and the dummy pipe 40 is connected by wrapping a heat-resistant tape or the like. Further, when a plurality of target materials 10 are used, the outer periphery around the joint between the target materials 10 may be connected by wrapping a heat-resistant tape or the like in the same manner as the method of connecting the target material 10 and the dummy pipe 40. ..

Next, as shown in FIGS. 3B and 3C, the backing tube 20 is coaxially installed in the hollow portion of the target material 10 connected to the dummy pipe 40. That is, it is important to arrange the target material 10 and the backing tube 20 in a state where the central axes coincide with each other and join them together. When the target material 10 and the backing tube 20 are joined via the joining material 31 in a state where the central axes of both are deviated, the center of the outer diameter and the center of the inner diameter of the obtained cylindrical sputtering target are inevitably deviated. As a result, the cylindrical sputtering target expands unevenly due to the heat load during sputtering, and the target material may be cracked or peeled off.

First, the backing tube 20 is coaxially arranged in the hollow portion of the target material 10 connected to the dummy pipe 40. As a method of arranging at this position, a known means can be used without particular limitation. For example, the backing tube 20 can be arranged coaxially with the hollow portion of the target material 10 by positioning using the XY stage and the fixture. Specifically, the backing tube 20 is installed by fixing one end to a pedestal 50 that can be positioned by an XY stage in a recess 51 formed on the upper surface of the pedestal 50. At this time, the upper end surface 21 of the backing tube 20 may be pressed by the second pressing mechanism 70 (see FIG. 4) described later. By pressing, the backing tube 20 is further fixed. In addition to fixing the backing tube 20 to the recess 51, the backing tube 20 may be fixed to an adhesive surface coated with an adhesive or the like.

The end of the backing tube 20 is sealed with a heat-resistant O-ring 52, and then the target is placed in the hollow portion of the target material 10 in the backing tube 20 so that the sealing side is downward. The material 10 and the backing tube 20 are arranged upright.

Further, in order to make the arrangement as shown in FIG. 3B, unlike the procedure described above, the backing tube 20 is coaxially installed in the hollow portion of the target material 10, and then the dummy pipe 40 is placed on the upper end surface 11 of the target material 10. May be concatenated.

Specifically, the backing tube 20 is coaxially arranged in the hollow portion of the target material 10 by positioning using the XY stage. The backing tube 20 is installed by fixing one end to a pedestal 50 that can be positioned by an XY stage in a recess 51 formed on the upper surface of the pedestal 50. The end of the backing tube 20 in the axial direction is sealed with a heat-resistant O-ring 52, and then the backing tube 20 is coaxially arranged in the hollow portion of the target material 10 so that the sealing side is downward. , The target material 10 and the backing tube 20 are arranged upright.

Then, the dummy pipe 40 is connected to the upper end surface 11 of the target material 10. Here, in order to align the central axes of the target material 10 and the dummy pipe 40, a spacer exceeding the length of the target material 10 and the dummy pipe 40 is circled in the clearance between the target material 10 and the dummy pipe 40 and the backing tube 20. The target material 10, the dummy pipe 40, and the backing tube 20 are aligned so that they are arranged at equal intervals in the circumferential direction. After that, the joint between the outer peripheral surfaces of the target material 10 and the dummy pipe 40 may be wound with heat-resistant tape and fixed at the same position. After connecting the target material 10 and the dummy pipe 40, the spacer used for aligning the central axes is removed.

Next, as shown in FIG. 3C, the lower side of the target material 10 is positioned by the XY stage, and the dummy pipe 40 side attaches the fixture 60 to the clearance between the dummy pipe 40 and the backing tube 20. .. As a result, the target material 10 and the backing tube 20 can be arranged coaxially. Further, since the fixture 60 is attached, the clearance width between the target material 10 and the backing tube 20 can be maintained constant.

Specifically, a plurality of fixtures 60 are attached to the clearance on the upper end side of the dummy pipe 40 and the backing tube 20 at equal intervals in the circumferential direction. As a result, in the filling step S3 and the joining step S4, which will be described later, the joining material to be filled in the clearance between the target material 10 and the backing tube 20 is joined while maintaining the clearance width between the target material 10 and the backing tube 20 evenly. The rate can be improved. Further, it is preferable that the fixtures 60 are attached at at least three places at equal intervals in the circumferential direction. Further, it is more preferable that the fixtures 60 are attached at four places at equal intervals in the circumferential direction from the viewpoint of ease of attachment at equal intervals and work efficiency such as securing a space for filling the joining material 31.

Further, as the fixture 60, it is preferable not only to arrange the fixture 60 near the upper end portion of the target material 10 but also to use a fixture 60 shorter than the length of the dummy pipe 40. As a result, the fixture 60 is limited to the clearance between the dummy pipe 40 and the backing tube 20, and the clearance between the target material 10 and the backing tube 20 can be filled only with the joining material 31 without the fixture 60. As a result, the bonding ratio of the produced cylindrical sputtering target 1 can be further increased.

As the fixture 60, for example, a spacer, a wedge, or a thickness gauge having a thickness equal to or slightly thinner than the clearance thickness can be used. The material of the fixture 60 is not particularly limited, and examples thereof include Teflon (registered trademark), SUS material, and Cu material.

Next, the pressing step S2 will be described with reference to the drawings. FIG. 4 is a cross-sectional view showing a pressing step included in the method for manufacturing a cylindrical sputtering target according to an embodiment of the present invention. FIG. 5 is a schematic plan view showing a first pressing mechanism used in the method for manufacturing a cylindrical sputtering target according to an embodiment of the present invention. In the pressing step S2, the upper end surface 41 of the dummy pipe 40 is pressed by the first pressing mechanism 70 to fix the target material 10 via the dummy pipe 40, and the upper end surface 21 of the backing tube 20 is seconded. This is a step of fixing the backing tube 20 by pressing with the pressing mechanism 80. In the present embodiment, the pressing step S2 may be further provided after the arranging step S1.

The first pressing mechanism 70 and the second pressing mechanism 80 maintain the width of the clearance between the target material 10 and the backing tube evenly in the filling step S3 and the joining step S4 described later, so that the target material 10 and the backing tube 20 are maintained. Has the function of fixing. As shown in FIG. 4, in order to arrange the backing tube 20 coaxially with the hollow portion of the target material 10, that is, in a state where their central axes coincide with each other in the arrangement step S1 which is the previous step, the first pressing mechanism The target material 10 is fixed by the 70 through the dummy pipe 40, and the backing tube 20 is fixed by the second pressing mechanism 80. A support column 53 is installed vertically at one end of the gantry 50, and a first pressing mechanism 70 and a second pressing mechanism 80 are attached to the support column 53, respectively.

The first pressing mechanism 70 is provided with a first pressing portion 72 extending horizontally from the support column 53 and a first pressing portion 72 below the tip end portion of the first arm portion 71. Further, the second pressing mechanism 80 is provided with a second pressing portion 82 extending horizontally from the support column 53 and a second pressing portion 82 below the tip portion of the second arm portion 81. .. The first and second pressing mechanisms 70 and 80 fix the target material 10 and the backing tube 20 by pressing the target material 10 and the backing tube 20 vertically downward from the support column 53 with screws, springs, or the like. When the backing tube 20 is sufficiently fixed to the gantry 50, only the target material 10 may be fixed by the first pressing mechanism 70 via the dummy pipe 40. That is, in the pressing step S2, at least the upper end surface 41 of the dummy pipe 40 of the target material 10 and the backing tube 20 is pressed by the first pressing mechanism 70, so that the target material 10 is fixed via the dummy pipe 40. You just have to.

Further, since the first pressing portion 72 supplies the joining material 31 to the clearance between the target material 10 and the backing tube 20 in the filling step S3 which is the next step, it is efficient without interfering with the supply of the joining material 31. The target material 10 may be fixed to the target material 10 in the vertical direction via the dummy pipe 40, as long as it is in contact with a predetermined region of the upper end surface 41 of the dummy pipe 40, and as shown in FIG. The one formed in a ring shape is preferable.

Next, the filling step S3 is a step of filling the clearance between the target material 10 and the backing tube 20 with the bonding material 31. That is, as shown in FIG. 3 (D), the target material 10 and the backing tube 20 are backed by attaching the fixture 60 to the clearance between the dummy pipe 40 and the backing tube 20 while keeping the target material 10 and the backing tube 20 upright. A constant clearance with the tube 20 is maintained, and only the bonding material 31 is filled in the clearance between the target material 10 and the backing tube 20.

Conventionally, the clearance between the target material and the backing tube has been filled with the bonding material and a plurality of spacers for maintaining the clearance have been arranged. Since the spacer is arranged on a curved surface having a narrow clearance, although it depends on the shape, voids are likely to be generated at the corners of the spacer, the contact portion with the curved surface, and the like when the joint material is filled. When sputtering is performed using a sputtering target having a bonded layer in which the voids are present, defects such as cracking and peeling may occur in the target material due to the heat load during sputtering. Further, as this spacer, a copper material or a stainless steel material having a high coefficient of thermal expansion is generally used, while an indium alloy is used as a bonding material. Therefore, there is a difference in the coefficient of thermal expansion between the clearance between the joint material only and the spacer, which causes cracks and chips in the target material. Further, since the portion where the spacer is provided comes into contact with the backing tube and is not joined by the bonding material, the target material and the backing tube are likely to be separated from each other when the temperature becomes high. Therefore, in the present embodiment, the above-mentioned problems can be prevented by filling the clearance with only the bonding material 31 so as not to leave the fixture 60 in the bonding layer 30.

In the filling step S3, in order to form the bonding layer 30 in the arranging step S1, the lower end side of the opening at both ends of the clearance between the target material 10 and the backing tube 20 is sealed by a sealing means such as a heat-resistant O-ring 52. Has been done. The target material 10 and the backing tube 20 are heated by a band heater (not shown) or the like above the melting point of the bonding material 31 poured between them.

Of the openings at both ends of the clearance between the target material 10 and the backing tube 20, the bonded material 31 in a molten state is poured from the upper end side that is not sealed. The filled liquid bonding material 31 is filled from the bottom of the clearance between the target material 10 and the backing tube 20.

In the present embodiment, as shown in FIG. 3D, the joining material 31 is filled up to a position higher than the upper end surface 11 of the target material 10, that is, a predetermined height position of the dummy pipe 40. If the dummy pipe 40 is not used, after filling the joining material 31, the joining material 31 shrinks in volume when the joining material 31 is cooled, and the joining material 31 is slightly reduced in the vicinity of the upper end surface 11 of the target material 10. There is a portion that is not filled (hereinafter, also referred to as an “unfilled portion”). Therefore, since there is an unfilled portion in the clearance between the target material 10 and the backing tube 20, the bonding ratio of the bonding material 31 decreases. Therefore, in the present embodiment, the joining ratio of the joining material 31 can be improved by filling the clearance between the dummy pipe 40 and the backing tube 20 with the joining material 31 up to a predetermined height position of the dummy pipe 40. Since the cylindrical sputtering target 1 produced in the present embodiment has a high bonding ratio, the bonding strength between the target material 10 and the backing tube 20 is high, and the thermal conductivity of the bonding layer 30 is good. As a result, in this cylindrical sputtering target 1, the cooling effect due to the passage of water inside the backing tube 20 is high, and a high power as in the magnetron sputtering method can be applied.

The predetermined height is 4% or more of the height of the target material from the lower end of the dummy pipe 40 in order to adjust the position of the upper end surface of the joint layer 30 to the same height as the upper end surface 11 of the target material 10. It is preferable to fill the bonding material 31 to the position. This lower limit value is a calculation of the height position of the dummy pipe 40 for filling the bonding material 31 based on the volume shrinkage ratio of indium from liquid to solid. In this way, the bonding material 31 made of indium melted to the height of the lower limit of the dummy pipe 40 is filled not only with the clearance between the target material 10 and the backing tube 20 but also with the clearance between the dummy pipe 40 and the backing tube 20. As a result, when the bonding material 31 is cooled, the position of the upper end surface of the bonding layer 30 becomes the same height as the upper end surface 11 of the target material 10, so that the cylindrical sputtering target 1 having a high bonding ratio can be obtained. The length of the dummy pipe 40 is set longer than the lower limit value. For example, it may be +10 mm from the above lower limit value. In the joining step S4 described later, when an extra joining layer is present in the joining layer 30 in which the joining material is solidified by cooling, the position of the upper end surface of the joining layer 30 is the upper end surface 11 of the target material 10. Remove excess bonding layer to adjust to the same height.

It is necessary to heat the target material 10 and the backing tube 20 in advance so that the surface temperature thereof is equal to or higher than the melting point of the bonding material 31, preferably 10 ° C. to 30 ° C. higher than the melting point. When the surface temperature of the target material 10 and the backing tube 20 is equal to or lower than the melting point of the bonding material 31, the bonding material 31 hardens at the same time as it comes into contact with the target material 10 or the backing tube 20, making it difficult to pour a sufficient amount of the bonding material 31. Become.

Similar to the backing tube 20 described above, the bonding layer 30 needs to select the bonding material 31 used for forming the bonding layer 30 in order to have properties such as thermal conductivity, electrical conductivity, and adhesive strength. There is. For example, the bonding material 31 containing indium as a main component has a lower hardness at the time of solidification than the bonding material containing tin as a main component. Therefore, when the bonding layer 30 is formed by using the bonding material 31 containing indium as a main component, defects such as cracks in the target material 10 occur in the process from the injection of the molten bonding material 31 to the solidification. It can be effectively prevented.

When the bonding layer 30 is formed by using the bonding material 31 containing indium as a main component, the content of indium is 50% by mass or more, preferably 70% by mass to 100% by mass, and more preferably 80% by mass to 100% by mass. It is necessary to use the one containing%. In particular, it is preferable to use a low melting point bonding material containing indium in an amount of 80% by mass or more, preferably 90% by mass to 100% by mass, as the bonding material 31. Such a low melting point bonding material is soft because the bond between atoms or molecules is weak, and has excellent workability because the hardness after cooling and solidification is in an appropriate range. Further, since the low melting point bonding material is not only excellent in workability but also has high fluidity at the time of melting, it is possible to easily form a uniform bonding layer 30 having extremely few nests (voids) and sink marks.

For example, when an indium metal having an indium content of 100% by mass is used as the bonding material 31, the thermal conductivity of the indium metal is 81.6 W / m · K, which is preferable because of its excellent thermal conductivity. Further, indium metal is preferable because it can be bonded with high adhesion to the target material 10 and the backing tube 20 by liquefying and solidifying.

On the other hand, when the indium content is less than 50% by mass, the wettability with the backing tube 20 side is low, so that the bonding material 31 melted by heating such a bonding material 31 is backed with the inner peripheral surface of the target material 10. It is not possible to inject into the gap between the outer peripheral surface of the tube 20 without a gap with high filling property.

Further, as the bonding material 31, in addition to the above-mentioned indium-based low melting point bonding material, a resin paste containing indium powder, a conductive resin, or the like can be used, but from the viewpoint of conductivity and spreadability, an indium-based material is used. A low melting point bonding material is preferable, and an indium-based low melting point bonding material having a melting point of 130 ° C. to 160 ° C. is more preferable. The components other than indium are not particularly limited, and for example, tin, antimony (Sb), zinc and the like can be contained as necessary. The content of the component other than indium is less than 50% by mass, preferably less than 30% by mass, and more preferably less than 20% by mass.

Next, in the joining step S4, as shown in FIG. 3 (E), the target material 10 and the joining material 31 filled in the clearance between the dummy pipe 40 and the backing tube 20 are cooled, and the target material 10 and the backing tube 20 are combined. It is a process of joining.

The surface of the target material 10 and the backing tube 20 is stopped from being heated by the band heater and allowed to cool to room temperature (20 ° C.), so that the filled bonding material 31 solidifies to form the bonding layer 30. The cooling means and the cooling speed can be adjusted as appropriate.

Next, as shown in FIG. 3 (F), after visually confirming that the bonding material 31 filled in the clearance between the target material 10 and the backing tube 20 is completely solidified to form the bonding layer 30. , The dummy pipe 40, the gantry 50, the heat-resistant O-ring 52, the fixture 60, etc. used in the arrangement step S1 are removed. In this way, the cylindrical sputtering target 1 is produced.

As described above, in the method for manufacturing a cylindrical sputtering target according to the present embodiment, a cylindrical dummy pipe is connected to the upper end surface of the target material, and a backing tube is coaxially installed in the hollow portion of the target material. The arrangement step S1 in which a plurality of fixtures are attached to the clearance between the dummy pipe and the backing tube at equal intervals in the circumferential direction, the filling step S3 in which the joint material is filled in the clearance between the target material and the backing tube, and the joint material are cooled. It has a joining step S4 for joining the target material and the backing tube. In the present embodiment, in the filling step S3 and the joining step S4, the joining ratio of the joining material to be filled in the clearance between the target material and the backing tube is improved while maintaining the width of the clearance between the target material and the backing tube evenly. be able to. Then, such a manufacturing method can manufacture a cylindrical sputtering target having a high bonding ratio at a simple and low cost.

Further, in the present embodiment, it is possible to obtain a cylindrical sputtering target in which defects such as cracking and peeling do not occur in the target material due to a heat load during sputtering.

Further, in the present embodiment, since such a cylindrical sputtering target can be easily obtained in industrial scale production, its industrial significance is extremely large.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples. In Examples 1 and 2, the following will be described with reference to a flow chart (see FIG. 2) showing an outline of the method for manufacturing a cylindrical sputtering target according to the above-described embodiment of the present invention.

(Example 1)
In Example 1, five ITO-made cylindrical ceramic sintered bodies having an outer diameter of 100 mm, an inner diameter of 81 mm, and a total length of 200 mm were prepared. Next, all the cylindrical ceramic sintered bodies were masked with heat-resistant masking tape in order to prevent excess bonding material from adhering to parts other than the inner peripheral surface to be the bonding surface. After that, for all the cylindrical ceramics sintered bodies, the inner peripheral surface to be the joint surface is wetted with indium, and five cylindrical ceramics sintered bodies are arranged at regular intervals so that the total length is 1000 mm, and the outer circumference is formed. A target material was obtained by fixing the surface with heat-resistant tape.

Next, in Example 1, a cylindrical backing tube obtained by lathe processing made of SUS304 having an outer diameter of 80 mm, an inner diameter of 70 mm, and a total length of 1100 mm was prepared. Of this cylindrical backing tube, the parts other than the joint surface were masked with heat-resistant tape in order to prevent excess bonding material from adhering. Then, glass beads # 80 were used as the projection material, and the cylindrical backing tube was blasted.

Then, using an ultrasonic soldering device (company name: Kuroda Techno Co., Ltd., product name: Sunbonder (registered trademark) USM-528), a known wetting operation using indium-based low melting point solder was performed.

Next, in the arrangement step S1, a dummy pipe (manufactured by SUS) having the same inner diameter and outer diameter as the target material and having a length of 50 mm was prepared. Five target materials and dummy pipes were arranged so that the dummy pipes were at the uppermost end, and a reference pipe having substantially the same inner diameter and outer diameter of the target material was installed in the hollow portion of the target material. Next, the joint between the target material and the outer peripheral surface of the dummy pipe was wrapped with heat-resistant tape and connected at the same position. Then, the reference pipe was removed from the target material to obtain a target material connected to the dummy pipe.

Next, the backing tube was installed with one end fixed to a pedestal that could be positioned by the XY stage. A heat-resistant O-ring was arranged at the end in the axial direction of this backing tube. After that, the dummy pipe was connected to the upper end surface of the target material. The backing tube was arranged in the hollow portion of the target material, and the target material and the backing tube were arranged upright so as to seal the lower side of the clearance with an O-ring. The dummy pipe was arranged so as to be above the target material.

In addition, the lower side of the target material is positioned by the XY stage, and on the dummy pipe side, four fixtures with a length of 10 mm are placed at equal intervals in the circumferential direction in the clearance between the dummy pipe and the backing tube. The backing tube was positioned coaxially with the hollow portion of the material. The clearance between the target material and the backing tube was 0.5 mm.

Subsequently, in the filling step S3, a band heater was attached to the outer peripheral surface of the target material, and the set temperature was set to 180 ° C. for heating. Further, an indium-based low melting point solder was prepared and heated to 190 ° C. by a band heater to melt it.

After confirming that the band heater had reached the set temperature, the molten bonding material was injected from the opening side of the upper clearance, and the bonding material was gradually filled from the lower end side. When a predetermined amount (1017 g) of the bonding material was injected, it was confirmed that the bonding material was filled to a predetermined height of the dummy pipe. Then, in the joining step S4, the band heater was switched off and allowed to cool to room temperature (20 ° C.). After confirming that the bonding material was completely solidified to form the bonding layer, the dummy pipe, fixture, masking tape, and heat-resistant O-ring were removed to obtain a cylindrical sputtering target.

In Example 1, the filling amount of the bonding material was measured with respect to the obtained cylindrical sputtering target using an ultrasonic flaw detector (company name: KJTD Co., Ltd., product name: SDS-WIN), and this measurement was performed. From the values, the bonding ratio between the target material and the cylindrical backing tube was evaluated. Specifically, those having a bonding ratio of 95.0% or more are "excellent (◎)", those having a bonding ratio of 90.0% or more and less than 95.0% are "good (○)", and less than 90.0%. Those whose target material fell off from the cylindrical backing tube and whose bonding ratio could not be evaluated were evaluated as "defective (x)".

In Example 1, as a result of evaluating the bonding ratio of the obtained cylindrical sputtering target by the above method, it was confirmed that all of them were excellent. Further, when a cylindrical sputtering target was attached to a magnetron type rotary cathode sputtering device and a discharge test was carried out at an output of 300 W in an argon atmosphere of 0.6 Pa, the target material was not cracked or chipped during sputtering. It was.

In Example 1, the bonding ratio and the results of the discharge test are shown in Table 1, respectively. The "bonding ratio" in Table 1 is the volume of the bonding layer (filling amount of the molten bonding material) when the bonding material is heated into the clearance and the bonding material is injected into the clearance with respect to the clearance volume. ). Further, in the "discharge test" in Table 1, the result of whether or not a defect such as cracking, chipping, or peeling of the cylindrical sputtering target occurred after the discharge test was indicated by "yes" or "no".

(Example 2)
In Example 2, the target material and the backing tube were prepared in the same manner as in Example 1. Next, in the arrangement step S1, the backing tube was installed by fixing one end to a pedestal that can be positioned by the XY stage. A heat-resistant O-ring was arranged at the end in the axial direction of this backing tube.

The lower end side of the clearance between the target material and the backing tube was sealed with a heat-resistant O-ring, the target materials were stacked, and a dummy pipe was placed on the upper end surface of the target material. Place three spacers that exceed the length of the target material and the dummy pipe in the clearance between the target material and the dummy pipe and the backing tube, align them so that they are coaxial, and then the outer peripheral surface of the target material and the dummy pipe. The joint was wrapped with heat-resistant tape and fixed in the same position. After fixing, the spacer was removed.

Next, the lower side of the target material is positioned by the XY stage, and on the dummy pipe side, three fixtures having a length of 10 mm are arranged at equal intervals in the circumferential direction in the clearance between the dummy pipe and the backing tube. The backing tube was positioned coaxially with the hollow portion of the target material.

Further, in the pressing step S2, the upper end surface of the dummy pipe was pressed by the pressing mechanism in order to prevent the clearance from being displaced when the joint material was filled. Other conditions were the same as in Example 1.

(Comparative Example 1)
In Comparative Example 1, a fixture was attached to the clearance between the target material and the backing tube without using a dummy pipe, and the fixture was not removed even after the joint material was filled in the clearance and cooled. A cylindrical sputtering target was prepared in the same manner as in the above. Table 1 shows the bonding ratio of this cylindrical sputtering target and the results of the discharge test.

(Discussion by Example)
From the results shown in Table 1, in Examples 1 and 2, by attaching a fixture to the clearance between the dummy pipe and the backing tube, cylindrical sputtering in which the clearance between the target material and the backing tube is filled with only the bonding material. The target was obtained. As a result, the bonding ratio became very high, and good results were obtained in the discharge test by sputtering using this cylindrical sputtering target.

On the other hand, in Comparative Example 1, the fixture was attached to the clearance between the target material and the backing tube without using the dummy pipe, and the fixture was not removed even after the joint material was filled in the clearance and cooled. Therefore, there is a fixture in the clearance, and a gap is generated in the vicinity thereof, so that a high bonding ratio cannot be obtained. Therefore, in Comparative Example 1, the discharge test could not be performed because the target material was cracked or chipped during the discharge test.

1 Cylindrical sputtering target, 10 target material, 11 top surface, 20 backing tube, 21 top surface, 30 bonding layer, 31 bonding material, 40 dummy pipe, 41 top surface, 50 pedestal, 51 recess, 52 heat resistant O-ring, 53 Strut, 60 Fixture, 70 1st presser, 71 1st arm, 72 1st press, 80 2nd press, 81 2nd arm, 82 2nd press, S1 arrangement Process, S2 pressing process, S3 filling process, S4 joining process

Claims (7)

A method for manufacturing a cylindrical sputtering target in which a molten bonding material is filled in a clearance between a target material made of a cylindrical ceramic sintered body and a cylindrical backing tube.
A cylindrical dummy pipe is connected to the upper end surface of the target material, the backing tube is coaxially installed in the hollow portion of the target material, and a plurality of fixtures are circled in the clearance between the dummy pipe and the backing tube. Arrangement process of mounting at equal intervals in the circumferential direction,
A filling step of filling the clearance between the target material and the backing tube with the bonding material,
A method for manufacturing a cylindrical sputtering target, which comprises a joining step of cooling the joining material and joining the target material and the backing tube. The method for manufacturing a cylindrical sputtering target according to claim 1, wherein the length of the fixture is shorter than the length of the dummy pipe. The method for manufacturing a cylindrical sputtering target according to claim 2, wherein in the filling step, the bonding material is further filled in the clearance between the dummy pipe and the backing tube to a predetermined height position of the dummy pipe. .. After the placement step, a pressing step for fixing the target material is further provided.
The method according to any one of claims 1 to 3, wherein in the pressing step, the target material is fixed via the dummy pipe by pressing the upper end surface of the dummy pipe with a pressing mechanism. How to make a cylindrical sputtering target. The method according to any one of claims 1 to 4, wherein in the arrangement step, the fixtures are attached to the clearance between the dummy pipe and the backing tube at four locations at equal intervals in the circumferential direction. How to make a cylindrical sputtering target. In the arrangement step, after connecting the dummy pipe to the upper end surface of the target material, the backing tube is coaxially installed in the hollow portion of the target material, and a plurality of clearances between the dummy pipe and the backing tube are provided. The method for manufacturing a cylindrical sputtering target according to any one of claims 1 to 5, wherein the fixtures are attached at equal intervals in the circumferential direction. In the arrangement step, after the backing tube is coaxially installed in the hollow portion of the target material, the dummy pipe is connected to the upper end surface of the target material, and a plurality of clearances between the dummy pipe and the backing tube are provided. The method for manufacturing a cylindrical sputtering target according to any one of claims 1 to 5, wherein the fixtures are attached at equal intervals in the circumferential direction.

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