JP6376101B2 - Cylindrical sputtering target and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cylindrical sputtering target and a method for producing the same, and is particularly preferably used in sputtering by a magnetron rotary cathode sputtering apparatus.

  Conventionally, as a sputtering target, a flat plate sputtering target obtained by bonding a flat target material to a backing plate is generally used. The use efficiency of the target material is 20% to 30% when sputtering is performed by a magnetron sputtering method using a flat plate sputtering target. The reason for this is that, in the magnetron sputtering method, the plasma concentrates and collides with a specific part of the target material due to the magnetic field, so that a phenomenon in which erosion progresses to a specific part of the surface occurs, and the deepest part of the target material is backing. This is because when it reaches the plate, its life is reached.

  In order to solve this problem, conventionally, it has been proposed to increase the use efficiency of the target material by making the shape of the sputtering target cylindrical. This method uses a cylindrical sputtering target consisting of a cylindrical backing tube and a cylindrical target material formed on the outer periphery thereof, and a magnetic field generating facility and a cooling facility are installed inside the backing tube, Sputtering is performed while rotating the sputtering target. By this method, the use efficiency of the target material can be increased to 60% to 70%.

  As a material of a target material in a cylindrical sputtering target, a metal material that can be easily processed into a cylindrical shape and has high mechanical strength is widely used. However, the processing into a cylindrical shape has not yet become widespread regarding a ceramic material having a characteristic that the mechanical strength is low and it is brittle.

  At present, ceramic cylindrical sputtering targets are manufactured by spraying ceramic powder on the outer periphery of a cylindrical backing tube or filling ceramic powder on the outer periphery of a cylindrical backing tube. It is limited to hot isostatic pressing (HIP) that fires ceramic powder in an inert atmosphere.

  However, thermal spraying has a problem that it is difficult to obtain a high-density target material, and hot isostatic pressing has a high initial cost and running cost, and cannot be peeled off due to a difference in thermal expansion and further cannot be recycled. There is a problem.

  For this reason, a cylindrical ceramic sintered body is formed by cold isostatic pressing (CIP) and fired to obtain a cylindrical ceramic sintered body. And it is desired to form a cylindrical sputtering target by bonding (bonding) this cylindrical ceramic sintered body to a backing tube.

  In a cylindrical sputtering target, a metal backing tube such as austenitic stainless steel or titanium is usually used. However, the backing tube made of stainless steel or titanium has a strong passive film on its surface, so it is difficult to join the backing tube with a high joining rate and joining strength via a joining material. is there.

  For this reason, a method of forming a base layer made of nickel or copper on the surface of austenitic stainless steel or titanium by electroplating for the purpose of avoiding contact with a strong passive film (see, for example, Patent Document 1). Proposed. In addition, after plating nickel or copper, a method of ultrasonic metallizing the bonding material (see, for example, Patent Document 2), or an ultrasonic trowel equipped with a heater on the bonding surface of a stainless steel backing tube. For example, a method of applying a bonding material while applying ultrasonic vibration (see, for example, Patent Document 3) has also been proposed.

Japanese National Patent Publication No. 10-509479 JP-A-8-67978 JP 2010-070842 A

  By these methods, the bonding strength between the backing tube and the bonding material is certainly improved. However, there is no particular description regarding the bonding strength between the cylindrical ceramic sintered body and the bonding material. For this reason, the bonding strength between the cylindrical ceramic sintered body and the bonding material becomes a problem.

  Accordingly, an object of the present invention is to provide a cylindrical sputtering target in which the bonding strength between the cylindrical ceramic sintered body and the bonding material is improved.

  In order to achieve the above object, the present inventors have made extensive studies on a method for joining a cylindrical ceramic sintered body and a joining material. As a result, it was found that the bonding strength between the cylindrical ceramic sintered body and the bonding material is improved by forming grinding marks with a high anchoring effect with a predetermined surface roughness on the joint surface of the cylindrical ceramic sintered body. . Moreover, not only the bonding strength was improved, but the strength of the cylindrical ceramic sintered body was improved. That is, by making the inner peripheral portion of the cylindrical ceramic sintered body a surface state having a high anchor effect, the strength of the cylindrical ceramic sintered body is improved. The knowledge that it was promoted was obtained. The present invention has been completed based on these findings.

  That is, a cylindrical sputtering target according to an aspect of the present invention for achieving the above object is coaxially provided between a target material made of a cylindrical ceramic sintered body and a hollow portion on the inner peripheral surface side of the target material. A backing tube to be disposed; and a bonding layer formed in a gap between the target material and the backing tube, and an inner peripheral surface of the target material has a grinding mark that runs in one direction and a grinding mark that runs in another direction. By providing at least one or more cross patterns formed by crossing with, the arithmetic average roughness Ra is 0.4 μm or more and 1.7 μm or less, and the ten-point average roughness Rz is 2.3 μm or more and 9.0 μm or less. It is formed in this.

  In one embodiment of the present invention, it is preferable that an obtuse angle formed by the intersection of the grinding trace traveling in the one direction and the grinding trace traveling in the other direction is 160 ° or less.

  In one embodiment of the present invention, the cylindrical ceramic sintered body is preferably composed of at least one oxide selected from the group consisting of In, Sn, Zn, Al, Nb, Ta, and Ti. .

  In one embodiment of the present invention, it is preferable that a bonding rate between the target material and the bonding layer is 98% or more, and a bonding strength between the target material and the bonding layer is 6.0 MPa or more. .

  Furthermore, a method for manufacturing a cylindrical sputtering target according to another aspect of the present invention includes a step of shift plunge grinding an inner peripheral surface of a target material made of a cylindrical ceramic sintered body using a grindstone, and shift plunge grinding. The inner circumferential surface is subjected to traverse grinding by reciprocating grinding in the longitudinal direction of the target material using the grindstone, and the inner circumferential surface subjected to traverse grinding is subjected to spark-out once to four times or less. And a step of spark-out grinding, wherein the grindstone has a particle size of # 100 or more and # 400 or less.

  According to the present invention, since the bonding rate and bonding strength between the target material and the bonding layer can be improved, the occurrence of cracking, chipping, and peeling during sputtering can be prevented, and sputtering can be performed stably and efficiently. .

It is a figure which shows the cylindrical sputtering target which concerns on one Embodiment of this invention, (A) is a schematic sectional drawing of a longitudinal direction, (B) is AA sectional drawing. It is a schematic sectional drawing of a target material among cylindrical sputtering targets concerning one embodiment of the present invention. It is a flowchart which shows the outline of the manufacturing method of the cylindrical sputtering target which concerns on one Embodiment of this invention.

  Embodiments of a cylindrical sputtering target to which the present invention is applied and a method for manufacturing the same will be described below. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention.

[1. Cylindrical sputtering target]
(1-1. Outline of cylindrical sputtering target)
First, the configuration of a cylindrical sputtering target according to an embodiment of the present invention will be described with reference to the drawings. 1A and 1B are diagrams showing a cylindrical sputtering target according to an embodiment of the present invention, in which FIG. 1A is a schematic cross-sectional view in the longitudinal direction, and FIG.

  As shown in FIG. 1A, a cylindrical sputtering target 1 is coaxially disposed in a target material 2 made of a cylindrical ceramic sintered body and a hollow portion on the inner peripheral surface 2a side of the target material 2. A backing tube 3 and a bonding layer 4 formed in a gap between the target material 2 and the backing tube 3 are provided. In this embodiment, the cylindrical sputtering target 1 has a backing tube 3 coaxially disposed in a hollow portion on the inner peripheral surface 2a side of the target material 2, and the center axes of the target material 2 and the backing tube 3 coincide with each other. It is what was joined via the joining layer 4 in the state. That is, the cylindrical sputtering target 1 is obtained by bonding the inner peripheral surface 2 a of the target material 2 and the outer peripheral surface of the backing tube 3 so as to be integrated through the bonding layer 4.

  The size of the cylindrical sputtering target 1 can be appropriately adjusted according to the material, customer demand, and the like, and is not particularly limited. For example, the case where a cylindrical ceramic sintered body having an outer diameter of 150 mm to 160 mm, an inner diameter of 134 mm to 140 mm, and a total length of 200 mm to 250 mm is obtained as the target material 2 will be described as an example.

(1-2. Target material)
The target material 2 is made of a cylindrical ceramic sintered body, and the cylindrical ceramic sintered body can be appropriately selected from materials according to applications, and is not particularly limited. For example, an oxide mainly composed of at least one selected from indium (In), tin (Sn), zinc (Zn), aluminum (Al), niobium (Nb), tantalum (Ta), and titanium (Ti) It is possible to use a cylindrical ceramic sintered body composed of the like.

In particular, a cylindrical ceramic sintered body mainly composed of indium oxide (In ₂ O ₃ ) or zinc oxide (ZnO), which is easily compatible with the low melting point bonding material, is used. Specifically, indium oxide (ITO) containing tin, indium oxide (ICO) containing cerium (Ce), indium oxide (IGO) containing gallium (Ga), indium oxide containing titanium (Ti) (ITO), indium oxide (IWO) containing tungsten (W), indium oxide (IYO) containing yttrium (Y), indium oxide (INiO) containing nickel (Ni), scandium (Sc) Indium oxide (IScO), Indium oxide containing silicon (Si) (ISiO), Indium oxide containing germanium (Ge) (IGeO), Indium oxide containing hafnium (Hf) (IHfO), Tantalum (Ta) Contains indium oxide (ITaO) and iron (Fe) Indium oxide (IFeO) containing praseodymium (Pr) Indium oxide (IPrO) containing europium (Eu) Indium oxide (IEuO) containing erbium (Er), dysprosium (Dy) Indium oxide (IDyO) containing manganese, manganese (Mn) containing indium oxide (IMnO), cobalt (Co) containing indium oxide (ICoO), magnesium (Mg) containing indium oxide (IMgO), zinc ( Zn) containing indium oxide IZO, gallium and zinc containing indium oxide (IGZO), aluminum containing zinc oxide (AZO), gallium containing zinc oxide (GZO), indium containing zinc oxide (ZIO) ) Magnesium Zinc oxide having (ZMgO), it can be suitably used gallium and aluminum zinc oxide containing (GAZO) cylindrical ceramic sintered body and the like as the target material 2.

  As shown in FIG. 1, in order to improve the wettability of the target material 2 with the bonding material forming the bonding layer 4, an indium or indium alloy underlayer is formed on the inner peripheral surface 2 a of the target material 2. Also good.

  The outer diameter of the target material 2 and the total length of the target material 2 can be appropriately adjusted according to the size of the cylindrical sputtering target 1. The inner diameter of the target material 2 can be appropriately adjusted according to the width of the gap and the outer diameter of the backing tube 3, and these are not particularly limited. Further, as the target material 2, not only one composed of one cylindrical ceramic sintered body but also one obtained by connecting a plurality of cylindrical ceramic sintered bodies can be used. The method for connecting the cylindrical ceramic sintered bodies is not particularly limited, and a known method can be used.

  FIG. 2 is a schematic cross-sectional view of the target material 2 in the cylindrical sputtering target 1 according to an embodiment of the present invention. The inner peripheral surface 2a of the target material 2 is provided with at least one cross pattern 6 formed by the intersection of the grinding trace 5a traveling in one direction and the grinding trace 5b traveling in the other direction.

  Conventionally, the target material 2 used for the cylindrical sputtering target 1 is obtained by precisely processing the inner peripheral surface 2a so that the surface is not damaged. Even if it sputters | spatters using this cylindrical sputtering target 1 using this target material 2, it causes the arcing which causes a crack, a chip, etc. from the damage | wound attached to the target material 2 in the first place, This is because it is considered that the situation of stopping the sputtering does not occur.

  However, the cylindrical sputtering target 1 which concerns on this Embodiment provides the cross pattern 6 in the internal peripheral surface 2a of the target material 2 in order to ensure the surface roughness of the internal peripheral surface 2a. When the target material 2 and the backing tube 3 are bonded, the cross pattern 6 improves the anchor effect of the bonding material and improves the bonding strength. Furthermore, by having the cross pattern 6 on the inner peripheral surface 2a of the target material 2, it is possible to obtain an appropriate strength by dispersing the force during impact or expansion.

  Therefore, at least one cross pattern 6 is provided on the inner peripheral surface 2a of the target material 2 formed by the intersection of the grinding trace 5a traveling in one direction and the grinding trace 5b traveling in the other direction.

  Furthermore, on the inner peripheral surface 2a of the target material 2, a plurality of grinding traces that run parallel to the grinding trace 5a that runs in one direction and a plurality of runs that run parallel to the grinding trace 5b that runs in the other direction. It is preferable to provide a plurality of cross patterns formed by crossing with grinding marks. Thereby, when the target material 2 and the backing tube 3 are bonded, a plurality of the cross patterns 6 are provided, whereby the anchor effect by the bonding material is further improved and the bonding strength is further improved.

  Moreover, it is preferable that the obtuse angle α formed by the intersection of the grinding trace 5a traveling in one direction and the grinding trace 5b traveling in the other direction is 160 ° or less. The obtuse angle α is formed by intersecting the grinding trace 5a in one direction and the grinding trace 5b in the other direction. As a result, the angle α of the cross pattern 6 on the inner peripheral surface 2a of the target material 2 increases the anchor effect by the bonding material more reliably during bonding to the backing tube 3, and further increases the bonding force. As a result, it can be used as a sputtering target that does not crack, chip, or peel off during sputtering.

  Furthermore, the inner peripheral surface 2a of the target material 2 is formed to have an arithmetic average roughness Ra of 0.4 μm or more and 1.7 μm or less by providing a cross pattern 6 and a ten-point average roughness Rz of 2.3 μm or more and 9.0 μm. Formed below. Thereby, since the surface roughness is rough, the bonding material enters the fine irregularities of the bonding surface between the inner peripheral surface 2a (bonding surface) of the target material 2 and the bonding layer 4, and the adhesive force is increased. An increasing effect (anchor effect) can be obtained.

  When the inner peripheral surface 2a of the target material 2 has an arithmetic average roughness Ra of less than 0.4 μm, or when the inner peripheral surface 2a of the target material 2 has a ten-point average roughness Rz of less than 2.3 μm, surface irregularities are present. Since it becomes small, an anchor effect falls and joining force weakens. On the other hand, when the inner peripheral surface 2a of the target material 2 exceeds the arithmetic average roughness Ra1.7 μm, or the inner peripheral surface 2a of the target material 2 exceeds the ten-point average roughness Rz by 9.0 μm, the unevenness is large. Therefore, even if vibration energy by ultrasonic vibration is applied, the vibration is difficult to penetrate, and the bonding force is weakened.

(1-3. Backing tube)
The cylindrical backing tube 3 is made of a material having thermal conductivity that can secure sufficient cooling efficiency that prevents the bonding layer 4 from deteriorating and melting when the cylindrical sputtering target 1 is used. What is necessary is just to have the intensity | strength etc. which can support the cylindrical sputtering target 1. FIG. As the backing tube 3, for example, various materials such as copper or copper alloy, titanium or titanium alloy, molybdenum or molybdenum alloy, aluminum or aluminum alloy are used in addition to those made of general austenitic stainless steel, particularly SUS304. be able to.

  When the backing tube 3 is made of stainless steel, it is preferable to coat copper as an underlayer in order to improve wettability with the bonding material.

  The total length of the backing tube 3 can be appropriately adjusted according to the size of the cylindrical sputtering target 1. The inner diameter of the backing tube 3 can be appropriately adjusted according to the sputtering apparatus, and these are not particularly limited. The outer diameter of the backing tube 3 is preferably set in consideration of the difference in linear expansion coefficient between the backing tube 3 and the target material 2 together with the thickness of the underlayer.

For example, as the target material 2, ITO having a linear expansion coefficient at 20 ° C. of 7.2 × 10 ⁻⁶ / ° C. is used, and as the backing tube 3, the linear expansion coefficient at 20 ° C. is 17.3 × 10 ⁻⁶ / ° C. When the SUS304 is used, the backing is set so that the width of the gap between the target material 2 and the backing tube 3 is preferably 0.3 mm to 3.0 mm, more preferably 0.5 mm to 1.0 mm. The outer diameter of the tube 3 and the inner diameter of the target material 2 are set.

  If the width of the gap between the target material 2 and the backing tube 3 is less than 0.3 mm, when the molten bonding material is injected into the gap, the backing tube may thermally expand and the target material 2 may be broken. On the other hand, when the width of the gap between the target material 2 and the backing tube 3 exceeds 3.0 mm, the backing tube 3 is coaxially disposed in the hollow portion of the target material 2 and joined in a state in which their central axes coincide. It becomes difficult.

(1-4. Bonding layer)
The bonding layer 4 is made of indium, for example, and bonds the target material 2 and the backing tube 3 together. The role of the bonding layer 4 is to transfer heat between the target material 2 and the backing tube 3 in order to dissipate the heat generated on the cylindrical sputtering target 1 by the discharge with the coolant flowing inside the backing tube 3. It is in. That is, the bonding layer 4 only needs to have thermal conductivity, electrical conductivity, adhesive strength, and the like in the same manner as the backing tube 3 when the cylindrical sputtering target 1 is used.

  In order to make the bonding layer 4 have the above-described characteristics such as thermal conductivity in the same manner as the above-described backing tube 3, it is necessary to select a bonding material used for forming the bonding layer 4. For example, a bonding material containing indium as a main component has a lower hardness when solidified than a bonding material containing tin as a main component. Therefore, in the case where the bonding layer 4 is formed using a bonding material mainly composed of indium, defects such as cracking of the target material 2 are effective in the process from injection of the molten bonding material to solidification. Can be prevented.

  When the bonding layer 4 is formed using a bonding material containing indium as a main component, indium is contained in an amount of 50% by mass or more, preferably 70% by mass to 100% by mass, more preferably 80% by mass to 100% by mass. You need to use something. In particular, a low melting point bonding material containing 80% by mass or more, preferably 90% by mass to 100% by mass of indium is preferably used as the bonding material. Such a low-melting-point bonding material is soft because the bonds between atoms or molecules are weak, and is excellent in workability because the hardness after cooling and solidification is in an appropriate range. In addition, the low melting point bonding material not only has excellent workability, but also has high fluidity at the time of melting. Therefore, it is possible to easily form the uniform bonding layer 4 with very few nests and sink marks.

  For example, when indium metal having an indium content of 100 mass% is used as the bonding material, it is preferable because the thermal conductivity of indium metal is 81.6 W / m · K and excellent in thermal conductivity. Further, indium metal is preferable because it can be bonded with good adhesion when the target material 2 and the backing tube 3 are bonded by solidifying after being liquefied.

  On the other hand, when the indium content is less than 50% by mass, the wettability with the backing tube 3 side is low, and thus the bonding material obtained by heating and melting such a bonding material is used as the gap between the target material 2 and the backing tube 3. In addition, it cannot be injected without gaps with high filling properties.

  As the bonding material, in addition to the indium-based low melting point bonding material described above, a resin paste containing indium powder, a conductive resin, or the like can be used. However, from the viewpoint of conductivity and spreadability, indium-based low melting point bonding is possible. An indium-based low melting point bonding material having a melting point of 130 ° C. to 160 ° C. is more preferable. In addition, it does not restrict | limit especially about components other than an indium, For example, tin, antimony (Sb), zinc, etc. can be contained as needed. The content of components other than indium is less than 50% by mass, preferably less than 30% by mass, and more preferably less than 20% by mass.

(1-5. Joint evaluation)
In the cylindrical sputtering target 1 according to the present embodiment, the bonding rate between the target material 2 and the bonding layer 4 is preferably 98% or more. Sputtering can be performed more stably with a high bonding rate. Note that the filling amount of the bonding material is measured using an ultrasonic flaw detector, and the bonding rate between the target material 2 and the bonding layer 4 is evaluated from the measured value.

  In addition, in the cylindrical sputtering target 1 according to the present embodiment, it is preferable that the bonding strength between the target material 2 and the bonding layer 4 is 6.0 MPa or more. In addition, based on the metal material tensile test method (JIS Z2241), it evaluates by measuring using a tensile tester.

  Thus, since the joining rate and joining strength are extremely high, cracking, chipping, and peeling do not occur during sputtering, and sputtering can be performed more stably and efficiently. Therefore, it is preferable that the bonding rate between the target material 2 and the bonding layer 4 is 98% or more, and the bonding strength between the target material 2 and the bonding layer 4 is 6.0 MPa or more.

  As described above, the cylindrical sputtering target 1 according to the present embodiment includes the target material 2 made of a cylindrical ceramic sintered body and the backing tube disposed coaxially in the hollow portion on the inner peripheral surface 2a side of the target material 2. 3 and a bonding layer 4 formed in the gap between the target material 2 and the backing tube 3. And the inner peripheral surface 2a of the target material 2 is provided with at least one cross pattern 6 formed by the intersection of the grinding trace 5a traveling in one direction and the grinding trace 5b traveling in the other direction. The arithmetic average roughness Ra is 0.4 μm or more and 1.7 μm or less, and the ten-point average roughness Rz is 2.3 μm or more and 9.0 μm or less.

  Therefore, since the surface roughness of the inner peripheral surface 2a of the target material 2 is rough, the cylindrical sputtering target 1 has an adhesive surface between the inner peripheral surface 2a (adhesive surface) of the target material 2 and the bonding material. An effect of increasing the adhesive force (anchor effect) is obtained by the bonding material entering and curing in the fine irregularities. Thereby, since the joining rate and joining strength of the target material 2 and the joining layer 4 can be improved, a crack, a chip | tip, and peeling do not arise at the time of sputtering, and it can perform sputtering more stably and efficiently.

[2. Manufacturing method of cylindrical sputtering target]
Hereinafter, the manufacturing method of the cylindrical sputtering target which concerns on this Embodiment is demonstrated.

(2-1. Outline of cylindrical sputtering target)
In the cylindrical sputtering target 1, the backing tube 3 subjected to the surface treatment as described above is coaxially arranged in the hollow portion of the target material 2, and the bonding layer 4 is bonded with a bonding material in the gap between the target material 2 and the backing tube 3. It is produced by forming. For example, the cylindrical sputtering target 1 is obtained by joining a backing tube 3 made of SUS304 to a target material 2 made of a cylindrical ceramic sintered body made of ITO using an indium-based low melting point joining material as a joining material. Can be produced.

(2-2. Processing of target material)
When machining a cylindrical workpiece, a lathe is generally used in many cases. This has the advantage that end face and inner / outer diameter machining can be performed in a lump, and is often used. However, in the case of ceramic processing, since it is a mechanism that processes while generating cracks, it is easy to process relatively sticky materials such as alumina and zirconia, but in the case of brittle materials such as ITO and AZO, there are cracks inside. In addition, since a crack often occurs when heat is applied in the subsequent bonding process, a grinding machine is often used.

  As shown in FIG. 3, the manufacturing method of the cylindrical sputtering target according to the present embodiment includes a step of performing shift plunge grinding on the inner peripheral surface 2a of the target material 2 made of a cylindrical ceramic sintered body using a grindstone ( Hereinafter, “shift plunge process S1”) and a process of traverse grinding the inner peripheral surface 2a subjected to shift plunge grinding in the longitudinal direction of the target material 2 using a grindstone (hereinafter referred to as “traverse process”). S2 ") and a step of spark-out grinding the inner peripheral surface 2a traversed by performing the spark-out once to four times (hereinafter referred to as" spark-out step S3 "). Thereby, the inner peripheral surface 2a of the target material 2 can be made into the desired surface roughness.

(Shift plunge process)
In the shift plunge step S1, the inner peripheral surface 2a of the target material 2 made of a cylindrical ceramic sintered body is subjected to shift plunge grinding using a grindstone. Here, shift plunge grinding is suitable for rough grinding.

  In the shift plunge step S1, the grain size of the grindstone used for shift plunge grinding is # 100 or more and # 400 or less. This will be described together in the traverse process described later.

  In the shift plunge step S1, it is preferable to grind the workpiece with a remaining allowance (cutting allowance) of 0.2 mm or less as an actual dimension by performing shift plunge grinding.

  Therefore, in the shift plunge process S1, the inner peripheral surface of the target material 2 is roughly ground.

(Traverse process)
In the traverse step S2, the inner peripheral surface 2a subjected to shift plunge grinding is traverse-ground by reciprocating grinding in the longitudinal direction of the target material 2 using a grindstone. This has the purpose of removing the grinding traces during shift plunge grinding and attaching the grinding traces of the cross pattern 6. Traverse grinding is suitable for precision grinding.

  In the traverse process S2, the grain size of the grindstone is # 100 or more and # 400 or less. If there is an error in the selection of the grindstone, grinding burn will occur and it will be difficult to obtain the desired surface roughness.

  If a grindstone with a grain size of less than # 100 is used, chipping frequently occurs due to the size of the abrasive grain, and it takes time and effort for correction, and the surface roughness becomes rough. It becomes easy. In addition, since the unevenness is too large, when applying the bonding material, ultrasonic vibrations do not reach, resulting in poor bonding. On the other hand, if a grindstone having a grindstone particle size exceeding # 400 can be used, the surface roughness can be reduced. However, since the irregularities of the sintered body are reduced, it is difficult to obtain an anchor effect. Therefore, in the traverse process S2, the grain size of the grindstone is # 100 or more and # 400 or less.

  As described above, the cylindrical sputtering target produced by the method of manufacturing a cylindrical sputtering target according to the present embodiment does not cause cracks, chips, peeling, etc. during sputtering on the inner peripheral surface 2a of the target material 2. A cross pattern is provided. In order to provide the cross pattern, as shown in FIG. 2, it is necessary to form grinding traces in two different directions, that is, a grinding trace 5a traveling in one direction and a grinding trace 5b traveling in the other direction. . Therefore, it is necessary to reciprocate the inner peripheral surface 2a of the target material 2 by traverse grinding.

  First, in the traverse step S2, traverse grinding is performed from one end side of the target material 2 toward the other end side of the target material 2 using a grindstone. As a result, as shown in FIG. 2, grinding marks 5a in one direction are formed on the inner peripheral surface 2a of the target material 2, respectively.

  Next, in the traverse step S2, traverse grinding is performed by returning from the other end side of the target material 2 to the one end side of the target material 2 using a grindstone. As a result, as shown in FIG. 2, grinding marks 5b in one direction are formed on the inner peripheral surface 2a of the target material 2, respectively.

  In this way, in the traverse step S2, the target material 2 is reciprocated once in the longitudinal direction using the grindstone. As a result, a plurality of cross patterns 6 can be provided on the inner peripheral surface 2 a of the target material 2. In the traverse process S2, the number of times is not particularly specified.

(Spark out process)
In the spark-out step S3, the inner peripheral surface subjected to traverse grinding is subjected to spark-out grinding by performing spark-out once or more and four or less times. In addition, a spark out means the operation | work which rotates a grindstone without giving a notch and removes the protrusion which exists in a processed surface.

  In the spark-out process S3, the spark-out is performed once or more and four or less times because the cloth pattern 6 attached during the traverse processing is not completely removed.

  When spark out is not performed, impurities are easily involved because the surface is rough. On the other hand, when the spark-out exceeds four times, grinding marks adhering during traverse processing are removed. For this reason, it is preferable to perform the spark-out 1 to 4 times.

  The target material 2 obtained under such conditions improves the anchor effect by the bonding material during bonding and improves the bonding strength. Furthermore, by providing the cloth pattern 6, it is possible to obtain an appropriate strength by dispersing the force during impact or expansion.

  In the spark-out process S3, considering the work efficiency and the elimination of problems at the time of joining, the inner peripheral surface 2a of the target material 2 is provided on the cloth pattern 6 by using a grindstone for the arithmetic average roughness Ra0. The surface roughness can be 4 μm or more and 1.7 μm or less, and the ten-point average roughness Rz 2.3 μm or more and 9.0 μm or less.

  And in the cylindrical sputtering target which concerns on this Embodiment, in order to obtain the desired grinding trace and surface roughness about the internal peripheral surface 2a of the target material 2, as above-mentioned, the shift plunge process S1 and the traverse process S2 The selection of the grindstone and the number of spark-outs in the spark process S3 are important.

(2-3. Example of target material processing)
As a method for manufacturing the cylindrical sputtering target according to the present embodiment, a processing method for obtaining surface roughness and intersecting grinding traces will be described below as an example.

  First, processing in the end face direction is performed, but may be performed by a known technique. In this method of manufacturing a cylindrical sputtering target, first, a target material 2 composed of a cylindrical ceramic sintered body is set on a surface grinding machine. The portion of the target material 2 that contacts the electromagnetic chuck is the lower part of the sintered body, and the surface that is not grounded is the upper part. At that time, the end face portion of the target material 2 after firing is uneven, and particularly, the surface that is in contact with the base plate during firing is greatly distorted. Even when the surface is not grounded, unevenness is produced when fine processing is not performed. For this reason, there is a blur when setting.

  Therefore, in order to remove the glare, a thickness gauge is placed between the electromagnetic chuck of the surface grinding machine and the target material 2 to be stabilized. At this time, measure the distance from the electromagnetic chuck to the upper part of the target material 2, determine one reference point, measure 4 to 8 points on the rating, and the height variation from the electromagnetic chuck within 0.5mm To get a simple vertical. This is because when it is desired to obtain parallelism with a small amount of grinding, it is difficult to obtain parallelism with a small amount of grinding unless the height is made uniform.

  Next, these are fixed, but a fixed block having a small thickness may be detached during processing. Therefore, it is preferable to fix with a fixing block having a height of about 2/3 with respect to the length direction of the target material 2. The amount of grinding at this time is not small, but a grinding amount of 0.1 mm plus the maximum thickness of the inserted thickness gauge is sufficient, and the upper end surface portion of the target material 2 hits the entire surface. good. If you do not win, you can assume that the set is defective.

  After confirming that the entire surface has hit, it is once removed from fixing, and then the lower part of the target material 2 is processed. Since the upper part of the target material 2 that contacts the electromagnetic chuck is in contact with the entire surface, it is not necessary to use a thickness gauge. Fixing is performed, and the lower part of the target material 2 is processed. As for the grinding amount at this time, a grinding amount of plus 0.1 mm is sufficient for the inserted thickness gauge. Now, the upper and lower surfaces of the target material 2 have come out, but the upper and lower surfaces of the target material 2 are once again processed. The purpose is to stabilize the surface state and increase the parallelism.

  The parallelism increases by performing the number of repeated processes at least four times. When fixing by adhesion at the next step of outer diameter processing, it is desirable to leave about 1 mm larger than the finished dimension and perform double-side processing again after the inner and outer diameter processing is completed. This is performed in order to completely remove the adhering temporary fixing adhesive.

  Next, the outer diameter portion is processed. In the example of this embodiment, a cylindrical grinder will be described as an example. Outside diameter machining is performed with a cylindrical grinder. Since it is possible to adjust the cutting depth and control the number of rotations of the workpiece, it is suitable for ITO and AZO processing, and it can be processed with a grindstone with the same specifications used in the surface grinder, so that each process has a grindstone This is because there is no need to make a selection.

  The reason why the outer diameter processing is performed first is that the inner diameter is easily fixed, so the outer diameter processing is performed. As described above, since the outer diameter portion of the target material 2 is distorted by the pressure received at the time of CIP, it is impossible to perform chucking with an evenly arranged force. If it is not a chucking method in which force is evenly distributed, cracking is likely to occur due to a load during processing. In addition, an internal grinding machine is used for inner diameter processing, but since the inside of the cylindrical shape is processed, the grinding wheel diameter becomes smaller and the peripheral speed of the grinding wheel cannot be gained, so the processing time is more than double that of outer diameter processing. It becomes. When processing efficiently, it is necessary to increase the amount of cut and secure chucking is required.

  Generally, it is performed by a scroll chuck. However, since the outer diameter portion and the inner diameter portion of the target material 2 are distorted, it is difficult to grasp evenly, and in such a case, bonding is preferable.

  Since the machining allowance of the workpiece is about 1 mm and the machining allowance is relatively large, grinding is divided into two processes, the shift plunge process S1 and the traverse process S2. Grind to 0.2 mm, and finish the remaining 0.2 mm by the traverse process S2.

  If the machining allowance at the time of traverse grinding in the traverse step S2 is 0.03 mm or more, the effect of finishing can be confirmed, but if it is less than 0.03 m, the cylindrical sputtering target according to the present embodiment In one example, since a grindstone of # 170 and relatively coarse abrasive grains is used, there may be a case where the grinding traces during roughing cannot be completely removed. Conversely, if the machining allowance is too large, it is easy to obtain a desired grinding mark, but it is not efficient because it takes too much time for finishing.

  Therefore, when using the above-described grindstone count, the machining allowance for the finishing process may be secured from 0.05 mm to 0.3 mm. Next, the workpiece was set on a table of a cylindrical grinder equipped with a # 170 grindstone. In this example, the rotation speed of the work is set to 100 rpm, and grinding is performed by shift plunge until the remaining machining allowance becomes 0.2 mm. When the remaining machining allowance is 0.2 mm, switching to traverse grinding is performed, and the reciprocating process is performed in the longitudinal direction of the target material 2 with the grindstone feed rate set to 0.6 m / min. Thereafter, in the spark process S3, spark out (zero grinding) is performed twice. As a result, the target material 2 obtained by processing the inner peripheral surface 2a can be produced.

  The inner peripheral surface 2a of the target material 2 after processing is finished by providing a cross pattern 6 with grinding marks 5a and 5b, so that the arithmetic average roughness Ra is 0.4 μm or more and 1.6 μm or less, and the ten-point average roughness Rz2. A surface roughness of 3 μm or more and 9.0 μm or less is formed.

(2-4. Arrangement of backing tube and target material)
Next, in the manufacturing method of the cylindrical sputtering target, the backing tube 3 is coaxially disposed in the hollow portion of the target material 2.

  Here, it is important to arrange the backing tube 3 coaxially in the hollow portion of the target material 2, that is, in a state in which these central axes coincide with each other, and to join the two. If they are joined with their center axes shifted, the center of the outer diameter and the center of the inner diameter of the resulting cylindrical sputtering target 1 will be shifted. As a result, the cylindrical sputtering target 1 may expand non-uniformly due to the thermal load during sputtering, and the target material 2 may be cracked or peeled off.

  In addition, as a method of arrange | positioning the backing tube 3 coaxially in the hollow part of the target material 2, a well-known means can be used without being restrict | limited in particular. For example, the backing tube 3 can be coaxially disposed in the hollow portion of the target material 2 by positioning using an XY stage.

  Next, in the method for manufacturing the cylindrical sputtering target, one end in the axial direction of the gap between the target material 2 and the backing tube 3 is sealed with a known sealing means such as an O-ring. And the target material 2 and the backing tube 3 stand upright so that this sealing side may become a downward direction.

  Next, a bonding material is injected into the gap between the inner peripheral surface 2 a of the target material 2 and the outer peripheral surface of the backing tube 3 to form the fitted bonding layer 4. Since the outer surface of the backing tube 3 is subjected to the surface treatment as described above, the bonding material adheres to the entire outer surface of the backing tube 3 by the surface treatment. As a result, the wettability of the outer peripheral surface of the backing tube 3 is improved, and the molten bonding material can be easily poured into the gap between the inner peripheral surface 2 a of the target material 2 and the outer peripheral surface of the backing tube 3.

  As described above, in the method of manufacturing a cylindrical sputtering target, the backing tube 3 is coaxially disposed in the hollow portion of the target material 2 made of a cylindrical ceramic sintered body, and the inner peripheral surface 2a is processed as described above. The cylindrical sputtering target 1 can be manufactured by forming the bonding layer 4 using a bonding material in the gap between the target material 2 and the backing tube 3.

  As a result, by using the target material 2 that has been subjected to the surface treatment when the cylindrical sputtering target 1 is manufactured, the bonding layer 4 having a high bonding rate and bonding strength can be formed during the manufacturing. And in the manufacturing method of a cylindrical sputtering target, the cylindrical sputtering target 1 which does not generate | occur | produce troubles, such as a crack, a chip | tip, and peeling at the time of sputtering, can be obtained.

  Moreover, in the manufacturing method of a cylindrical sputtering target, since such a cylindrical sputtering target 1 can be obtained easily in industrial scale production, the industrial significance is very large.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example and a comparative example, this invention is not limited to these Examples and a comparative example.

Example 1
In Example 1, in order to obtain a cylindrical sputtering target having a length of 200 mm and a thickness of 8 mm, a cylindrical ceramic sintered body having an outer diameter of 151 mm and an inner diameter of 135 mm was prepared. Next, in order to obtain this processed body, a cylindrical ceramic molded body was formed by cold isostatic pressing (CIP) and fired.

  In Example 1, a target material 2 constituting a ceramic sintered body made of ITO (indium tin oxide) having a cylindrical shape was obtained. The target material 2 had a length of 208 mm, an outer diameter of 155 mm, and an inner diameter of 131 mm.

  In Example 1, this target material 2 is set on a surface grinder to which a grindstone having a particle size of # 170 is attached, and a 0.5 mm and a 0.3 mm thickness gauge are inserted in order to suppress glare, and an electromagnetic chuck The distance from the upper end of the target material 2 to within 0.5 mm was adjusted to the end face.

  Then, in Example 1, the end surface part of the lower end part of the target material 2 which is the opposite side was also processed to obtain a target material 2 having a length of 202 mm. In order to perform outer diameter processing, it was fixed to a jig by bonding and set on a table of a cylindrical grinder. A grindstone with a grain size of # 170 was used for outer diameter machining as in the end face machining with a surface grinder. After processing the outer diameter to 155 mm, the sintered body was peeled off from the adhesive and the target material was attached to the scroll chuck in order to perform inner diameter processing. For the inner diameter processing, a grindstone having a particle size of # 170 was used as in the end face and outer diameter processing.

  First, in the shift plunge step S1 in Example 1, the inner peripheral surface 2a of the target material 2 was processed by shift plunge grinding using a grindstone having a particle size of # 170 until the remaining allowance was 0.1 mm. Next, in the traverse step S2, the inner peripheral surface 2a of the target material 2 that has been subjected to shift plunge grinding and the remaining machining allowance is 0.1 mm is traversed with a grindstone feed rate of 0.6 m / min. A reciprocating process was performed in the longitudinal direction of the target material 2. Next, in the spark-out step S3, the spark-out was performed twice to finish the inner diameter of 155 mm, and the target material 2 was produced.

  In Example 1, when the internal peripheral surface of the target material 2 was observed visually, it confirmed that it had the some cross pattern 6 by the grinding traces 5a and 5b. Furthermore, when the surface roughness of the inner peripheral surface 2a of the target material 2 was measured, the arithmetic average roughness Ra was 1.3 μm, and the ten-point average roughness Rz was 6.7 μm.

  In Example 1, a backing tube (manufactured by SUS304) having an outer diameter of 133 mm, an inner diameter of 125 mm, and a length of 1300 mm was prepared, and an ultrasonic soldering apparatus (Kuroda Techno Co., Ltd., Sunbonder (registered trademark) USM) heated to 200 ° C. -528) and indium was used as the bonding material. A bonding material was brought into close contact with the outer peripheral surface of the backing tube 3 to apply an impact by ultrasonic vibration and pressurize. As the bonding material, indium-based low melting point solder containing 80% by mass of indium, 10% by mass of tin, 5% by mass of antimony, and 5% by mass of zinc was used. Specifically, first, the temperature of the ultrasonic striking terminal was set to 200 ° C., and the optimum frequency was set to 28.0 kHz using the automatic adjustment function of the ultrasonic soldering apparatus while melting the indium-based low melting point solder.

  In Example 1, similarly to the backing tube 3, the inner peripheral surface 2a of the target material 2 was brought into close contact with each other, applied with an impact by ultrasonic vibration, and pressed to apply the bonding material.

  In Example 1, the oxide adhering to the backing tube 3 and the inner peripheral surface 2a of the target material 2 is removed by a scraper, the target material 2 is inserted into the backing tube 3, heated again, and then molten indium is poured. It was. And this operation | work was repeated and the cylindrical sputtering target 1 with a total length of 1200 mm was produced.

  In Example 1, after the produced cylindrical sputtering target 1 was completely cooled, the filling amount of the bonding material was measured using an ultrasonic flaw detector (manufactured by KJTD, SDS-WIN). From the numerical values, the bonding rate between the target material 2 and the bonding layer 4 was evaluated. As a result, when evaluated, the joining rate was 99%.

  Further, the bonding strength between the target material 2 and the bonding layer 4 was evaluated by measurement using a tensile tester (manufactured by Shimadzu Corporation, Autograph) based on a metal material tensile test method (JIS Z2241). As a result, it was found that the bonding strength was 7.0 MPa, which is a high strength bonding rate.

  Further, when the cylindrical sputtering target 1 was destroyed after the sputtering evaluation, it was confirmed that there was no target material 2 that peeled off from the backing tube 3, and sufficient strength was maintained and bonded.

  In Example 1, when the cylindrical sputtering target 1 is attached to a magnetron rotary cathode sputtering apparatus and sputtered at a power of 15 Kw / m in an argon atmosphere of 3.0 Pa, the cylindrical sputtering target 1 is cracked or chipped. It never happened.

  In Example 1, these results are summarized in Table 1.

(Examples 2 to 5 and Comparative Examples 1 to 5)
In Example 2 to Example 5 and Comparative Example 1 to Comparative Example 5, the count of the grindstone used during the inner diameter processing, the number of spark-outs, the surface roughness of the inner peripheral surface 2a of the target material 2, the joining rate, and the joining strength As shown in Table 1, cylindrical sputtering targets 1 were produced.

(Summary)
From the results shown in Table 1, in Examples 1 to 5, in the processing of the inner peripheral surface 2a of the target material 2, grinding is performed at an appropriate feed rate of the grindstone using a grindstone having a particle size # 100 or more and a particle size # 400 or less. By performing the processing and performing zero grinding once to four times, the inner peripheral surface 2a of the target material 2 is provided with a cross pattern 6 by grinding marks 5a and 5b, and the arithmetic average of the inner peripheral surface 2a in the axial direction A target material 2 having a surface roughness with a roughness Ra of 0.4 μm or more and 1.7 μm or less and a ten-point average roughness Rz of 2.3 μm or more and 9.0 μm or less was obtained.

  In Examples 1 to 5, the bonding rate between the target material 2 and the bonding layer 4 was a high bonding rate of 98% or more. In general, it is said that sputtering can be stably performed if the bonding rate between the target material 2 and the bonding layer 4 is 95% or more. However, in the current technology, the bonding between the target material 2 and the bonding layer 4 is possible. There is a report that the rate is getting 97%. In Examples 1 to 5, the bonding rate between the target material 2 and the bonding layer 4 was over 97%.

  In Examples 1 to 5, the bonding strength between the target material 2 and the bonding layer 4 was as high as 6.0 MPa or more. In general, if the bonding strength between the target material 2 and the bonding layer 4 is 6.0 MPa or more, there is no fear of the target falling off during sputtering.

  On the other hand, in Comparative Example 1, the target material 2 was prepared in the same manner as in Example 1 except that # 80 was used as the grindstone count. In the cutting process, the surface roughness becomes rough and the unevenness becomes large. Therefore, when applying the bonding material, the ultrasonic vibration does not reach, and the bonding strength between the target material 2 and the bonding layer 4 is the first to the second embodiments. Compared to Example 5, it decreased.

  On the other hand, in Comparative Example 2, the target material 2 was prepared in the same manner as in Example 1 except that # 800 was used as the grindstone count. In the cutting process, the surface roughness is reduced and the unevenness is reduced, whereby the anchor effect is reduced, and the bonding strength between the target material 2 and the bonding layer 4 is decreased as compared with Examples 1 to 5. .

  On the other hand, in Comparative Example 3 to Comparative Example 5, a cross pattern is not obtained on the processed surface, the anchor effect on the entire surface is reduced, and the bonding strength between the target material 2 and the bonding layer 4 is that of Example 1 to Example. Compared to 5, it decreased.

  From the above results, in the processing of the inner peripheral surface 2a of the target material 2, the inner peripheral surface of the target material 2 is obtained by performing a spark-out after traversing using a grindstone having a particle size # 100 or more and a particle size # 400 or less. 2a is provided with a cross pattern 6 formed by grinding marks 5a and 5b, the arithmetic average roughness Ra in the axial direction of the inner peripheral surface 2a is 0.4 μm or more and 1.7 μm or less, and the ten-point average roughness Rz is 2.3 μm or more. It was found that the target material 2 having a surface roughness of 9.0 μm or less was obtained.

  Thus, it was found that by securing the surface roughness, the cylindrical sputtering target 1 according to the present embodiment improves the bonding strength between the target material 2 and the bonding layer 4.

DESCRIPTION OF SYMBOLS 1 Cylindrical sputtering target, 2 Target material, 2a Inner peripheral surface, 3 Backing tube, 4 Bonding layer, 5a Grinding trace of one direction, 5b Grinding trace of other direction, 6 Cross pattern

Claims (5)

A target material made of a cylindrical ceramic sintered body;
A backing tube disposed coaxially in the hollow portion on the inner peripheral surface side of the target material,
A bonding layer formed in the gap between the target material and the backing tube,
Arithmetic average roughness Ra0 is provided by providing at least one cross pattern formed on the inner peripheral surface of the target material by the intersection of the grinding trace running in one direction and the grinding trace running in the other direction. A cylindrical sputtering target characterized by being formed to a thickness of 0.4 μm to 1.7 μm and a ten-point average roughness Rz of 2.3 μm to 9.0 μm.   2. The cylindrical sputtering target according to claim 1, wherein an obtuse angle formed by the intersection of the grinding trace running in the one direction and the grinding trace running in the other direction is 160 ° or less.   The cylindrical ceramic sintered body is composed of at least one oxide selected from the group consisting of In, Sn, Zn, Al, Nb, Ta, and Ti. 2. The cylindrical sputtering target according to 2.   The bonding rate between the target material and the bonding layer is 98% or more, and the bonding strength between the target material and the bonding layer is 6.0 MPa or more. The cylindrical sputtering target of any one of these. A step of shift plunge grinding the inner peripheral surface of a target material made of a cylindrical ceramic sintered body using a grindstone;
A step of traverse grinding the inner peripheral surface that has been shift plunge ground by reciprocating grinding in the longitudinal direction of the target material using the grindstone,
A step of spark-out grinding the inner peripheral surface subjected to traverse grinding by performing spark-out once or more and four or less times,
A method for producing a cylindrical sputtering target, wherein the grindstone has a particle size of # 100 or more and # 400 or less.

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