WO2018186385A1 - Cylindrical sputtering target, and production method therefor - Google Patents

Abstract

The present invention includes: a surface treatment step in which a surface treating bonding material is applied to an inner circumferential surface, i.e. a bonding surface, of a cylindrical target (2), and/or an outer circumferential surface, i.e. a bonding surface, of a cylindrical backing tube (3), to form a surface treatment layer (11); and a bonding step which is performed after the surface treatment step, and in which a gap between the cylindrical target (2) and the backing tube (3) inserted into the cylindrical target is filled with a filling bonding material, and said filling bonding material is hardened. The melting point and the solidus temperature of the surface treating bonding material exceed the melting point and the solidus temperature of the filling bonding material.

Description

Cylindrical sputtering target and manufacturing method thereof

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. 2017-076471 filed in Japan on April 7, 2017 and Japanese Patent Application No. 2018-56467 filed in Japan on March 23, 2018. Is hereby incorporated by reference.

A sputtering apparatus that performs sputtering while rotating a cylindrical sputtering target is known. As shown in Patent Document 1 or Patent Document 2, the cylindrical sputtering target used in this sputtering apparatus has the inner peripheral surface of the cylindrical target joined to the outer peripheral surface of the cylindrical backing tube.
In this bonding, the same or similar coating as the bonding material is applied to the outer peripheral surface of the cylindrical backing tube as the bonding surface and the inner peripheral surface of the cylindrical target for the welding process using an ultrasonic welder (ultrasonic soldering iron). After that, a joining method is known in which a cylindrical backing tube is inserted into a cylindrical target, a gap for a joint is provided between the two, and a joining material is supplied into the gap to fill the gap. ing. It is also known to use indium (In) as a bonding material.

Japanese Unexamined Patent Publication No. 2016-74377 (A) Japanese Unexamined Patent Publication No. 2014-37619 (A)

By the way, the cylindrical backing tube and the cylindrical target are joined by heating the backing tube and the target, ground treatment by the ground treatment joining material, cooling it, inserting the backing tube into the target, and a gap for the joining material between them. A series of processes are required: forming, assembling, reheating the target and backing tube, filling gaps in the bonding material, and cooling.
Here, the ground treatment of the target and the backing tube will be described. In the ground treatment, the target and the backing tube are heated to a melting point or higher of the ground treatment bonding material, and an outer surface of the backing tube and an inner circumferential surface of the target are used by using an ultrasonic soldering iron. This is a step of applying a base treatment bonding material.

Surface oxidation of the surface of the base treatment bonding material of the target and the backing tube proceeds by cooling after the base treatment and reheating before bonding for filling the gap between them with the bonding material.
Due to the formation of the oxide film on the surface of the base treatment bonding material, the contact between the filling material to be filled and the base treatment bonding material is hindered, and poor bonding is likely to occur, and a predetermined bonding area ratio is obtained in ultrasonic flaw inspection after bonding. The quality of the product may be rejected.
The sputtering target in which such quality is rejected requires heating the whole to melt the bonding material, and then removing the target from the backing tube and re-bonding. On the other hand, with an increase in the size of the substrate to be sputtered, the cylindrical target has become longer, and an improvement in bonding strength is also desired.

In view of such circumstances, the present invention prevents the occurrence of bonding failure due to the oxide film on the surface of the bonding material subjected to the base treatment, improves the yield by reducing the reworking operation, and the bonding strength between the target and the backing tube. The purpose is to increase.

A manufacturing method of a cylindrical sputtering target which is one embodiment of the present invention (hereinafter referred to as “a manufacturing method of a cylindrical sputtering target of the present invention”) includes an outer peripheral surface of a cylindrical backing tube and an inner peripheral surface of the cylindrical target. Is a method of manufacturing a cylindrical sputtering target in which a gap provided between the bonding surfaces is filled with a bonding material and bonded, and the inner peripheral surface of the cylindrical target and the cylindrical backing tube A base treatment step of forming a base treatment layer by applying a base treatment bonding material to at least one of the outer peripheral surface as a joining surface, and after the base treatment step, the cylindrical target and the cylindrical target inserted into the cylindrical target A bonding step of filling the bonding material for filling into a gap between the backing tube and solidifying, and melting or solidus temperature of the base treatment bonding material There has been above the melting point or solidus temperature of the filling bonding material.

In this manufacturing method, the surface of the ground treatment layer formed in the ground treatment process is oxidized during cooling after application of the ground treatment bonding material and during heating in the joining process to form an oxide film. When the melting point or solidus temperature of the base treatment bonding material is higher than the melting point or liquidus temperature of the filling bonding material, the temperature during bonding can be set to an intermediate temperature between the two. With this temperature setting, the base treatment bonding material is heated in the solid phase in the heating process for filling the filling bonding material, so that oxidation is suppressed and bonding failure is reduced.

In the manufacturing method of the cylindrical sputtering target of the present invention, the base treatment bonding material is a pure tin or tin alloy having a tin content of 90% by mass or more, and the filling bonding material has an indium content of 85% by mass or more. It may be pure indium or an indium alloy.

In this manufacturing method, the surface of the base treatment layer is melted during heating during the joining step by setting the joining temperature in the joining step to the melting point of indium (about 157 ° C.) or higher and below the melting point of the base treatment joining material. Therefore, oxidation of the surface of the base treatment layer due to heating before bonding can be suppressed. Further, when the filling bonding material and the base treatment bonding material are in contact with each other at the bonding interface, wettability is improved by the effect of the eutectic reaction between tin and indium, and bonding defects can be reduced. Further, the reason why the bonding failure is reduced is that the oxide film on the surface of the base treatment layer is a tin oxide, so the density is lower than that of the filling bonding material. Therefore, the cylindrical target and the cylindrical backing tube It is mentioned that the oxide film peeled off from the surface of the base treatment layer floats on the melted part while filling the gap between the melted filling bonding material. This effect makes it difficult for oxides to remain in the filled bonding material even after the bonding is completed.
In this case, the filling bonding material may be an indium alloy containing 15% by mass or less of tin.

In the method for producing a cylindrical sputtering target of the present invention, at least one of the base treatment step and the bonding step may be performed in an inert atmosphere.
Oxidation can be prevented as much as possible by the inert atmosphere, and the joint strength can be further improved. In this case, in the base treatment process, an inert atmosphere is maintained at least from the start of application of the base treatment bonding material to the completion of cooling, and in the bonding process, at least from the start of heating to the completion of filling of the filling bonding material. It only has to be done.
In the method of manufacturing a cylindrical sputtering target according to the present invention, the bonding step includes the cylindrical target and the backing tube inserted into the cylindrical target at a melting point or a solidus temperature of the filling bonding material or higher. A reheating step of reheating at a temperature lower than the melting point or solidus temperature of the base treatment bonding material may be provided.

A cylindrical sputtering target according to another aspect of the present invention (hereinafter referred to as “cylindrical sputtering target of the present invention”) has a cylindrical backing tube inserted into the cylindrical target, and an outer peripheral surface of the cylindrical backing tube and a cylindrical shape. A joint including indium and tin is formed between the inner peripheral surface of the target, and in a cross section of the joint perpendicular to the central axis of the cylindrical backing tube, the joint between the cylindrical target and the joint The tin concentration in the thickness range of 10 μm from at least one of the bonding interface and the bonding interface between the cylindrical backing tube and the bonding portion to the inside of the bonding portion is S1% by mass, and the thickness of the bonding portion When the tin concentration in the center of the direction is S2% by mass, (S1 / S2) ≧ 1.5.

When joining a cylindrical target and a cylindrical backing tube, tin is preliminarily applied to at least one of the inner peripheral surface of the cylindrical target and the outer peripheral surface of the cylindrical backing tube before filling the bonding material therebetween. The base treatment material as a component is applied in advance, but if a tin concentration gradient occurs in the thickness direction in the joined portion after joining as described above, the ground treatment layer becomes compatible with the joined portion. The joint strength is improved. In this case, if (S1 / S2) is less than 1.5, the joining force of the joining portion is reduced, and the cylindrical target may be displaced on the cylindrical backing tube during sputtering.

According to the present invention, it is possible to prevent the occurrence of bonding failure due to the oxide film on the surface of the bonding material subjected to the ground treatment, reduce the reworking operation, improve the yield, and increase the bonding strength between the target and the backing tube. .

It is a longitudinal cross-sectional view of the cylindrical sputtering target of embodiment of this invention. It is a cross-sectional view of FIG. It is the expanded sectional view of the part shown by A of FIG. 1, and the schematic diagram of the component profile in the cross section of a junction part. It is a flowchart explaining 1st Embodiment of the manufacturing method of a cylindrical sputtering target. It is a longitudinal cross-sectional view which shows the state in the middle of manufacture in the manufacturing method of 1st Embodiment. It is a flowchart explaining 2nd Embodiment of the manufacturing method of a cylindrical sputtering target. It is a longitudinal cross-sectional view which shows the state in the middle of manufacture in the manufacturing method of 2nd Embodiment. It is a longitudinal cross-sectional view which shows the state in the middle of manufacture in the manufacturing method of 2nd Embodiment.

Embodiments of a cylindrical sputtering target and a method for manufacturing the same according to the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 and 2, the cylindrical sputtering target 1 includes a cylindrical backing tube 3 inserted into a cylindrical target 2, and an inner peripheral surface of the cylindrical target 2 and an outer peripheral surface of the cylindrical backing tube 3. Are joined via a joint 4. In this case, the cylindrical target 2 and the cylindrical backing tube 3 are arranged in a state where the central axes coincide with each other.

The material and dimensions of the cylindrical target 2 and the cylindrical backing tube 3 are not particularly limited. For example, the cylindrical target 2 has an inner diameter of 134 mm to 137 mm made of metal such as copper (Cu), silver (Ag), titanium (Ti), ceramics such as silicon (Si), zinc oxide doped with aluminum (AZO), or the like. These cylindrical members can be used. For example, the cylindrical backing tube 3 may be a cylindrical member made of titanium (Ti), stainless steel (SUS), copper or a copper alloy and having an outer diameter of 133 mm to 136 mm mm and a length of 1 m to 3 m. In this case, the cylindrical target 2 is disposed on the outer periphery of the cylindrical backing tube 3 in a state where a plurality of short target materials 2 a having a length of about 30 cm are connected via the packing 5. The packing 5 is removed when the bonding material becomes 100 ° C. or higher after the bonding material is solidified and solidified during the bonding material cooling step. With the cylindrical backing tube 3 inserted into the cylindrical target 2, a gap of 0.5 mm to 2 mm is formed in the radial direction between them. As will be described later, a spacer 6 for holding the gap is inserted into the gap, and the cylindrical target 2 and the cylindrical backing tube 3 are integrated with the spacer 6 together by the joint 4.

The joint 4 is, for example, pure indium or an indium alloy having an indium content of 85% by mass or more, and contains 15% by mass or less of tin. In this case, since the cylindrical sputtering target 1 is manufactured through a bonding process after the base treatment process as will be described later, the concentration gradient of indium (In) and tin (Sn) as shown in FIG. Is generated in the thickness direction, and within a thickness range of 10 μm from the bonding interface between the cylindrical target 2 and the bonding portion 4 and from the bonding interface between the cylindrical backing tube 3 and the bonding portion 4 to the inside of the bonding portion 4 (see FIG. 3 (position P1) at a tin concentration (average value) of S1% by mass, and the central portion in the thickness direction of the joint 4 (the thickness of the joint 4 is T, the position T / 2 from the joint interface ( When the tin concentration at the position P2)) in FIG. 3 is S2% by mass, (S1 / S2) ≧ 1.5.
Although not particularly limited, the upper limit of the content of indium contained in the joint portion 4 at the position P2 is (99.99) mass%. Similarly, although not particularly limited, a preferable indium content at the position P2 of the joint portion 4 is 90.00 mass% to (99.97 mass%, more preferably 95.00 mass% to 99.95 mass%. It is.
Although not particularly limited, the lower limit value of the content of tin contained in the joint portion 4 at the position P2 is 0.01% by mass. Similarly, although not particularly limited, the content of tin contained in the preferred joint 4 is 0.1% by mass to 5.0% by mass, and more preferably 0.2% by mass to 1.0% by mass.
Although not particularly limited, the upper limit value of S1 / S2 is 1500. Similarly, although not particularly limited, a preferable range of S1 / S2 is 5 ≦ (S1 / S2) <1000, and more preferably 20 ≦ (S1 / S2) <100.

<Method of manufacturing cylindrical sputtering target>
Next, a first embodiment of the method for manufacturing the cylindrical sputtering target 1 will be described. In the first embodiment, as shown in the flowchart of FIG. 4, the heating process of the cylindrical backing tube 3 and the cylindrical target 2, the ground treatment process using the ground treatment bonding material, the ground treatment bonding material cooling process, and the cylindrical target 2 Inserting cylindrical backing tube 3 into assembly and assembling process to form joint gap between them, reheating process of cylindrical target 2 and cylindrical backing tube 3, filling filling filler into gap The joining material filling step and the joining material cooling step are performed in this order. Hereinafter, it demonstrates in order of a process.

(Heating process)
The cylindrical target 2 and the cylindrical backing tube 3 are heated, and the inner peripheral surface of the cylindrical target 2 and the outer peripheral surface of the cylindrical backing tube 3 serving as the joint surfaces thereof are used as the melting point (or liquidus temperature of the base treatment bonding material). ) Heat to above temperature. For example, when pure tin (purity: 99.8% by mass or more) is used as the base treatment bonding material, it is heated to 232 ° C. or more.

(Ground treatment process)
The ground treatment bonding material in the molten state is applied to the inner peripheral surface of the cylindrical target 2 and the outer peripheral surface of the cylindrical backing tube 3 which are heated in the heating step. In this case, the surface treatment bonding material is applied to the inner peripheral surface of the cylindrical target 2 and the outer peripheral surface of the cylindrical backing tube 3 while applying ultrasonic vibration with an ultrasonic soldering iron (not shown) equipped with a heater. Removal of dirt and oxide films is promoted, and the surface treatment bonding material can be made to conform to these surfaces. As the base treatment bonding material, pure tin or a tin alloy having a tin content of 90% by mass or more is used.
As the tin alloy, an indium tin alloy containing 15% by mass or less of indium is preferable. A tin alloy in which the amount of indium added exceeds 15% by mass has a melting point (liquidus temperature) of 180 ° C. or lower, oxidation at the bonding surface proceeds by heating during bonding, and an oxide film is rolled into the bonded portion. Strength may be reduced.
Although not particularly limited, the upper limit value of the tin content of the base treatment bonding material is 100% by mass. Similarly, although not particularly limited, the tin content of a preferable base treatment bonding material is 90% by mass to 100% by mass, and more preferably 95% by mass to 100% by mass.
In addition, as a base treatment bonding material, a copper-tin alloy containing 0.7% by mass or less of copper (eg, Sn-0.7Cu alloy), a tin-zinc alloy containing 9% by mass or less of zinc, 3.5 A silver tin alloy containing less than or equal to mass% silver can also be used.
When the base treatment step is performed in an inert atmosphere such as argon or nitrogen, the surface of the base treatment layer formed by the base treatment bonding material can be prevented from being oxidized. This inert atmosphere is preferably maintained at least from the start of application of the base treatment material until the cooling of the base treatment joint material is completed in the next base treatment joint material cooling step.

(Base treatment bonding material cooling process)
The cylindrical target 2 and the cylindrical backing tube 3 coated with the base treatment bonding material are cooled to room temperature (20 ° C.) to solidify the base treatment bonding material. As a result, the ground treatment layer 11 is formed on the inner peripheral surface of the cylindrical target 2 and the outer peripheral surface of the cylindrical backing tube. The thickness of the base treatment layer 11 is not particularly limited, but is preferably 10 μm or more and 200 μm or less. When the thickness of the ground treatment layer 11 is less than 10 μm, it is difficult to sufficiently apply the ground treatment bonding material to the cylindrical target 2 and the cylindrical backing tube 3, and the cylindrical target 2 and the cylindrical backing tube 3. The surface of the material is likely to be exposed, and a bonding failure is likely to occur when the filling bonding material is subsequently filled. If the thickness of the ground treatment layer 11 exceeds 200 μm, the bonding material accumulates downward due to gravity after the ground treatment, and the cylindrical backing tube 3 cannot be passed through the cylindrical target 2 during assembly, making it difficult to manufacture. May be.
Although not particularly limited, the thickness of the base treatment layer 11 is more preferably 30 μm to 150 μm, and still more preferably 50 μm to 100 μm.
Note that, in the base treatment bonding material cooling step, the oxide on the surface of the base treatment layer 11 after solidification may be mechanically removed at room temperature. Alternatively, the oxide on the surface of the base treatment layer 11 may be damaged to reach the bonding material under the oxide. Thus, by removing all or part of the oxide on the surface of the base treatment layer 11 at room temperature, the familiarity between the base treatment joint material and the filling joint material is further improved in the joint material filling step.

(Assembly process)
As shown in FIG. 5, first, the cylindrical target 2 is placed on a fixed base 13 having a recess 13 a in which the end of the cylindrical backing tube 3 can be placed so as to surround the recess 13 a. Next, the cylindrical backing tube 3 is inserted into the cylindrical target 2 and arranged coaxially with a certain gap in the circumferential direction therebetween. A spacer 6 is disposed between the cylindrical target 2 and the cylindrical backing tube 3 in order to provide a constant gap in the circumferential direction. As the spacer 6, a wire made of a metal such as copper or stainless steel is preferable, and a spacer having an outer diameter corresponding to the gap between the cylindrical target 2 and the cylindrical backing tube 3 is used. By inserting a plurality of, for example, three spacers 6 at regular intervals in the circumferential direction of the gap, the cylindrical target 2 and the cylindrical backing tube 3 are coaxially arranged with a constant gap in the circumferential direction.

(Reheating process)
The cylindrical target 2 and the cylindrical backing tube 3 assembled as described above are heated by a heater (not shown), and the melting point (or liquidus temperature) of the filling bonding material is equal to or higher than the melting point of the base treatment bonding material. (Or solidus temperature) Set to a temperature below. In this way, the cylindrical target 2 and the cylindrical backing tube 3 are heated to a temperature not lower than the melting point (or liquidus temperature) of the filling bonding material and not higher than the melting point (or solidus temperature) of the base treatment bonding material. By doing so, the base treatment layer 11 is not melted, and oxidation due to heating can be suppressed.
Although it does not specifically limit, The temperature of a preferable reheating process is 145 degreeC or more and less than 200 degreeC, More preferably, it is 160 degreeC or more and less than 180 degreeC.
Similarly, the heating time in the preferred reheating process is 10 minutes to 3 hours, more preferably 30 minutes to 2 hours.

(Bonding material filling process)
The heated cylindrical target 2 and the cylindrical backing tube 3 are arranged along the vertical direction, and the lower end of the gap is closed by the packing 5 as shown by the arrow B in FIG. Filled with a filling filling material in a molten state. The filling bonding material accumulates in the lower part of the gap held by the spacer 6 and is gradually filled toward the upper part. A receiving tray 12 for receiving the filling bonding material overflowing from the gap is provided at the upper end of the gap, and the receiving tray 12 is filled until the filling bonding material overflows.

As this filling bonding material, an indium alloy containing 15% by mass or less of tin is suitable. An indium alloy having a tin concentration of more than 15% by mass as a bonding material for filling has a melting point of less than 140 ° C. when the tin concentration exceeds 15% by mass and is 79% by mass or less, and heat conduction from the cylindrical target 2 during sputtering. May cause the cylindrical target 2 to move on the cylindrical backing tube 3 and shift. On the other hand, when the content is 79% by mass or more, due to a temperature difference between the solid phase line and the liquid phase line, poor bonding due to the shrinkage tends to occur when the filling bonding material solidifies.
When this filling bonding material is filled in the gap between the cylindrical target 2 and the cylindrical backing tube 3, as described above, the main component of the ground treatment layer 11 is tin, and the main component of the filling bonding material is indium. Therefore, the wettability is improved by the effect of eutectic reaction between tin and indium. Moreover, since the oxide on the surface of the base treatment layer is an oxide of tin, the density is lower than that of the filling bonding material, and by overflowing the bonding material at the uppermost end of the gap, the oxide is levitated and is released from the gap. Can be removed. For this reason, it is difficult for the oxide to remain in the joint.
As the filling bonding material, not only the above-mentioned indium alloy, but also those in Table 1 can be applied as a combination with the base treatment bonding material.

By using the combinations shown in Table 1, the melting point of the base treatment bonding material is set higher than the melting point of the filling bonding material, the bonding temperature can be set in the middle region between the two, and the rework work associated with the bonding failure is reduced. In addition, the bonding strength can be improved.
The density of the bonding material and oxide is as shown in Table 2.

As shown in Table 2, the density of the oxide film (tin oxide) formed on the surface of the base treatment layer by using tin (Sn) as the base treatment bonding material and indium (In) as the filling bonding material Is smaller than the density of indium. Therefore, by filling the gap between the cylindrical target 2 and the cylindrical backing tube 3 with the filling bonding material made of indium, it is possible to float and remove the tin oxide on the surface of the base treatment layer.

Note that the reheating step and the bonding material filling step (at least until the filling is completed) are performed in an inert atmosphere, thereby suppressing the oxidation of the bonding material and further improving the bonding strength.

(Bonding material cooling process)
After filling the gap between the cylindrical target 2 and the cylindrical backing tube 3 with a filling bonding material, this is cooled and solidified to remove unnecessary deposits and the like, and then cleaned. The cylindrical sputtering target 1 in which the cylindrical backing tube 3 is integrated by the joint 4 is completed.
Since this cylindrical sputtering target 1 is formed by forming a base treatment layer 11 containing tin as a main component and then integrating it with a filling bonding material containing indium as a main component, Thus, the concentration gradient of tin and indium is generated in the thickness direction. In addition, since the oxide residue on the surface of the base treatment layer 11 is suppressed, the base treatment layer 11 is integrated with the bonding portion 4 so as to reduce the bonding failure and improve the bonding strength.

In this case, the tin concentration within the thickness range of 10 μm from the joint interface between the cylindrical target 2 and the joint 4 and the joint interface between the cylindrical backing tube 3 and the joint 4 into the joint 4 is S1 mass%. When the tin concentration in the central part in the thickness direction of the joint is S2% by mass, (S1 / S2) ≧ 1.5. When (S1 / S2) <1.5, the bonding force of the bonding portion 4 is reduced, and the cylindrical target 2 may be displaced on the cylindrical backing tube 3 during sputtering.

In the above-described embodiment, after the cylindrical target 2 and the cylindrical backing tube 3 are coaxially assembled, the molten bonding material is supplied from above the gap. You may fill by the same method.
A flowchart in that case is shown in FIG. The steps from (heating step) to (priming treatment bonding material cooling step) are the same as those in the manufacturing method of the first embodiment described above. Then, instead of the fixed base 13 on which the cylindrical target 2 is placed, a jig having a concave portion for storing a molten filling bonding material is used, and the jig is disposed on the jig 14 and immediately above the concave portion 15. As described above, the cylindrical target 2 is vertically supported through the packing 5. Further, the bonding material is heated in the recess 15 of the jig 14 and stored in a molten state in advance (bonding material melting step). Then, as shown in FIG. 7A, the cylindrical backing tube 3 whose lower end is closed by the dummy plug 16 is inserted into the cylindrical target 2, and the cylindrical target 2 and the cylindrical backing tube 3 are connected to a heater (not shown). And is set to a temperature not lower than the melting point (or liquidus temperature) of the filling bonding material and not higher than the melting point (or solidus temperature) of the base treatment bonding material (reheating step). Next, the gap between the cylindrical backing tube 3 and the cylindrical target 2 is gradually filled with the molten filling bonding material F from below. As shown in FIG. 7B, when the filling bonding material F overflows the receiving tray 12 at the upper end of the cylindrical target 2, the filling is completed (bonding material filling step). In this embodiment, the bonding material filling step is also a step of assembling the cylindrical target 2 and the cylindrical backing tube 3.

In the above-described embodiment, the base treatment bonding material is applied to both the inner peripheral surface of the cylindrical target 2 and the outer peripheral surface of the cylindrical backing tube 3, but either surface is easily wetted with the filling bonding material. If it is in a state, application of the base treatment bonding material may be omitted on the surface.

<Example 1>
10 pieces of silicon (Si) cylindrical target doped with boron (B) (specific resistance 0.05 Ω · cm, inner diameter: 137 mm, outer diameter: 157 mm, length: 200 mm, hereinafter referred to as Si-TG), pure Five cylindrical backing tubes made of titanium (Ti) (inner diameter: 125 mm, outer diameter: 135 mm, length: 600 mm, hereinafter referred to as Ti-BT) were prepared.
The outer peripheral surface of Si-TG was heated using a mantle heater until the inner peripheral surface temperature of Si-TG reached 240 to 260 ° C. The temperature was maintained at around 250 ° C., and pure tin (Sn) was used as a base treatment bonding material, and the inner peripheral surface of Si-TG was subjected to a ground treatment with an ultrasonic soldering iron in the air atmosphere, and then cooled to room temperature.
Ti-BT is heated until the temperature of the outer peripheral surface of Ti-BT reaches 240 to 260 ° C. by circulating hot air on the inner peripheral surface. The temperature was maintained at around 250 ° C., and pure tin (Sn) was used as a base treatment bonding material, and the outer peripheral surface of Ti-BT was ground-treated with an ultrasonic soldering iron in an air atmosphere and cooled to room temperature.
After the base treatment, two pieces of Si-TG were placed at a predetermined position of Ti-BT. Between the cylindrical targets, a heat-resistant fluororesin packing (thickness of about 0.6 mm) was sandwiched so that the bonding material did not leak during filling of the bonding material. As for the assembly of Ti-BT and Si-TG, the diameter: 0.6 mm copper wire (spacer) is inserted at three places at intervals of about 120 °, and the bonding material is between Si-TG and Ti-BT. A gap for filling was formed.
After the gap is formed, the bonding material is filled by heating the outer peripheral surface of Si-TG with a mantle heater in the atmosphere and maintaining the inner peripheral surface temperature of Ti-BT at around 180 ° C., then, Japanese Patent Application Laid-Open No. 2014-37619. In the method shown in FIG. 6 (method shown in FIGS. 6, 7A and 7B), pure indium (In) was filled as a bonding material from the bottom to the top. At the top, the bonding material overflowed and the oxide floated. Using the same process, no. A total of five cylindrical sputtering targets 1 to 5 were produced.
After cooling, the bonding area ratio was measured with an ultrasonic flaw detection apparatus. The bonding area ratio is the ratio of the bonded area excluding the defective bonding portion to the total area of the bonding surface of Si-TG and Ti-BT. When the bonding area ratio was 95% or more, it was evaluated as acceptable. In this case, when the bonding was not successful in one bonding, the bonding material was melted and removed, then bonded again, and the bonding area ratio was measured.

No. From the sample 1, 20 samples for bonding strength measurement including a bonded portion having a diameter of 20 mm were collected from an arbitrary position in the radial direction and subjected to a tensile test. The average value of the 20 strengths was taken as the tensile strength of the joint.
No. A sample for observing a cross-sectional structure was prepared from the sample 1 and the bonding interface was observed at a magnification of 2000 times. Quantitative analysis of tin (Sn) concentration was performed with EPMA at a beam diameter of about 1 μm within a range of about 10 μm from each of the Ti-BT bonding interface and the Si-TG bonding interface (point P1 in FIG. 3). . In this case, the Ti-BT bonding interface side is the BT side interface, the Si-TG bonding interface side is the TG interface, the tin concentration at the P1 point near the BT side interface is SB, and the tin concentration at the P1 point near the TG side interface Was ST, and the average value (ST + SB) / 2 was S1. Further, the tin (Sn) concentration (S2) in the center portion of the filling material in the same sample (position of about 0.5 mm from each bonding interface: point P2 in FIG. 3) is quantitatively analyzed by EPMA, and S1 / S2 was determined.

<Example 2>
As a base treatment bonding material, Sn-1 wt% In (No. 6, melting point 224 ° C.), Sn-5 wt% In (No. 7, melting point 215 ° C.), Sn-10 wt% In (No. 8, melting point) 200 ° C.), and a cylindrical sputtering target is manufactured in the same manner as in Example 1 except that the base processing temperatures are 240 ° C., 230 ° C., and 215 ° C. The rate was measured. After the ultrasonic flaw detection test was completed, a sample for bonding strength measurement and a sample for cross-sectional observation were prepared in the same manner as in Example 1, and a tensile test and quantitative analysis of tin (Sn) concentration by EPMA were performed.

<Example 3>
As a base treatment bonding material, Sn-3.5 wt% Ag (No. 9, melting point 221 ° C.), Sn-9 wt% Zn (No. 10, melting point 198 ° C.), Sn-0.7 wt% Cu (No 11 and a melting point of 227 ° C.), and a cylindrical sputtering target was manufactured in the same manner as in Example 1 except that the base treatment temperatures were 240 ° C., 215 ° C., and 240 ° C. The bonding area ratio was measured with an apparatus. After the ultrasonic flaw detection test was completed, a sample for bonding strength measurement and a sample for cross-sectional observation were prepared in the same manner as in Example 1, and a tensile test and quantitative analysis of tin (Sn) concentration by EPMA were performed.

<Example 4>
As a bonding material for filling, In-5 wt% Sn, (No. 12, melting point 150 ° C.), In-10 wt% Sn (No. 13, melting point 144 ° C.), In-15 wt% Sn (No. 14, The melting point is 140 ° C., and the cylindrical target is manufactured in the same manner as in Example 1 except that the bonding temperatures are 165 ° C., 160 ° C., and 155 ° C. Measure. After the ultrasonic flaw detection test was completed, a sample for bonding strength measurement and a sample for cross-sectional observation were prepared in the same manner as in Example 1, and a tensile test and quantitative analysis of tin (Sn) concentration by EPMA were performed.

<Example 5>
Three cylindrical sputtering targets (Nos. 15 to 17) were produced in the same manner as in Example 1 except that the base treatment step and / or the bonding step was performed in a nitrogen atmosphere.
After cooling, the bonding area ratio was measured with an ultrasonic flaw detection apparatus.
No. From the 15 samples, a sample for bonding strength measurement and a sample for cross-sectional observation were prepared in the same manner as in Example 1, and a tensile test and quantitative analysis of tin (Sn) concentration by EPMA were performed.

<Conventional example>
The outer peripheral surface of Si-TG is heated using a mantle heater, the temperature of the outer peripheral surface of Si-TG is maintained at around 180 ° C., and pure indium (In) is used as a base treatment bonding material in the atmosphere to form Si -The inner surface of the TG was ground with an ultrasonic soldering iron.
In Ti-BT, hot air is circulated on the inner peripheral surface, the temperature of the outer peripheral surface of Ti-BT is maintained at around 180 ° C., and pure indium (In) is used as a base treatment bonding material, and the outer peripheral surface of Ti-BT is super The substrate was treated with a sonic soldering iron.
After the base treatment, Si-TG was inserted one by one into a predetermined position of Ti-BT. Between the cylindrical targets, a heat-resistant fluororesin packing (about 0.6 mm) was sandwiched so that the bonding material did not leak during the bonding. As for the assembly of Ti-BT and Si-TG, diameter: 0.6mm copper wire (spacer)) is inserted at three places at intervals of about 120 ° and joined between Si-TG and Ti-BT. A gap for filling the material was formed.
After the gap is formed, the bonding material is filled by the method shown in Japanese Patent Application Laid-Open No. 2014-37619 after the outer peripheral surface of Si-TG is heated with a mantle heater and the inner peripheral surface temperature of Ti-BT is maintained at around 180 ° C. 6, 7 </ b> A, and 7 </ b> B), pure indium (In) was filled as a bonding material from the bottom to the top. At the top, the bonding material overflowed and the oxide floated. Using the same process, five cylindrical targets were manufactured (No. 18 to No. 22).
After cooling, the bonding area ratio was measured with an ultrasonic flaw detection apparatus.
No. Twenty samples for bonding strength measurement including a bonded portion having a diameter of 20 mm were prepared from 18 samples from arbitrary positions and subjected to a tensile test.

<Comparative example>
For both Si-TG and Ti-BT, Sn-20 wt% In (No. 23, melting point 136 ° C.) and Sn-30 wt% In (No. 24, melting point 125 ° C.) were used as the base treatment bonding material. A cylindrical target was manufactured by the same method as in Example 1 except that the processing temperatures were 160 ° C. and 135 ° C., respectively, and the bonding area ratio was measured by an ultrasonic flaw detection apparatus after cooling. After the ultrasonic flaw detection test was completed, a sample for bonding strength measurement and a sample for cross-sectional observation were prepared in the same manner as in Example 1, and a tensile test and quantitative analysis of tin (Sn) concentration by EPMA were performed.

Table 3 shows the manufacturing conditions and bonding rate of each sample, and Table 4 shows the results of tensile strength and tin concentration analysis. In Table 3, the joining rate was determined to be 95% or more.
In Table 3, the melting point when the base treatment bonding material is an alloy indicates the solidus temperature or eutectic point, and the melting point when the filling bonding material is an alloy indicates the liquidus temperature. Among the manufacturing conditions described in Table 3, for the atmosphere in the base treatment process and the atmosphere in the filling process, the adopted atmosphere is indicated by “check mark”, and the non-adopted atmosphere is “N / A ”(Not Applicable).

As can be seen from the results in Table 3, the joining rate (area ratio) was as high as 95% or more by using a filling joining material having a melting point lower than that of the base treatment joining material. Even in the conventional example, there is one in which a joining rate of 95% or more is obtained, but it is a result of re-joining twice or more, and 80% is a result of passing 95% or more in one joining. It was. On the other hand, in the example, a bonding rate of 95% or more was obtained in all the samples by one bonding, and it can be seen that the yield is superior to the conventional example. Among them, the bonding rate was particularly high when the base treatment process or the bonding material filling process was performed in an inert atmosphere.
Further, as shown in Table 4, when the tin content of the base treatment bonding material is 90% by mass or more and the indium content of the filling bonding material is 85% by mass or more, the tin concentration distribution (S1 / S2) is 1.5 or more, and high bonding strength is obtained.

High-quality cylindrical sputtering target can be produced efficiently.

DESCRIPTION OF SYMBOLS 1 Cylindrical sputtering target 2 Cylindrical target 2a Target material 3 Cylindrical backing tube 4 Joining part 5 Packing 6 Spacer 11 Substrate treatment layer 12 Sauce pan 13 Fixing base 14 Jig 15 Concave part 16 Dummy plug

Claims (5)

1. A method of manufacturing a cylindrical sputtering target, in which an outer peripheral surface of a cylindrical backing tube and an inner peripheral surface of a cylindrical target are joined surfaces, and a gap provided between the joined surfaces is filled with a joining material and joined. A ground treatment step of forming a ground treatment layer by applying a ground treatment bonding material to at least one of an inner circumferential surface as a joining surface of a target and an outer circumferential surface as a joining surface of the cylindrical backing tube; And a bonding step of filling and solidifying the gap between the cylindrical target and the backing tube inserted into the cylindrical target by filling with a filling bonding material, the melting point or solid phase of the base treatment bonding material A method for producing a cylindrical sputtering target, wherein a linear temperature exceeds a melting point or a solidus temperature of the filling bonding material.
2. The base treatment bonding material is pure tin or a tin alloy having a tin content of 90% by mass or more, and the filling bonding material is pure indium or an indium alloy having an indium content of 85% by mass or more. The manufacturing method of the cylindrical sputtering target of Claim 1.
3. 3. The method for manufacturing a cylindrical sputtering target according to claim 1, wherein at least one of the base treatment step and the bonding step is performed in an inert atmosphere.
4. The joining step includes
   The cylindrical target and the backing tube inserted into the cylindrical target are at a temperature equal to or higher than the melting point or solidus temperature of the filling bonding material and lower than the melting point or solidus temperature of the ground treatment bonding material. The method for producing a cylindrical sputtering target according to any one of claims 1 to 3, further comprising a reheating step of reheating.
5. A cylindrical backing tube is inserted into the cylindrical target, and a joint including indium and tin is formed between the outer peripheral surface of the cylindrical backing tube and the inner peripheral surface of the cylindrical target, and the cylindrical backing tube In the cross section of the joint perpendicular to the central axis of the joint, from the joint interface between the cylindrical target and the joint and from the joint interface between the cylindrical backing tube and the joint, the inside of the joint (S1 / S2) ≧ 1.5 when the tin concentration in the thickness range of 10 μm is S1 mass% and the tin concentration in the central portion in the thickness direction of the joint is S2 mass%. A cylindrical sputtering target characterized by

Images