JP6677853B1 - Sputtering target, method for joining target material and backing plate, and method for manufacturing sputtering target - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering target in which a target material is hardly peeled off. A sputtering target includes a backing plate and a target material bonded to a bonding region of the backing plate via a bonding material, and a bonding area of a bonding portion between the target material and the backing plate is It is 97% or more with respect to the area of the bonding area, and the maximum defect area of the portion between the target material and the backing plate where the bonding material does not exist is 0.6% with respect to the area of the bonding area. It is the following. [Selection] Fig. 1C

Description

  The present invention relates to a sputtering target, a method for bonding a target material and a backing plate, and a method for manufacturing a sputtering target.

  As a conventional joining method of a sputtering target, there is a method described in Japanese Patent Application Laid-Open No. 6-114549 (Patent Document 1). In this method of joining a sputtering target, a coating of a molten brazing material is formed on each of a target material and a backing plate, and the target material and the backing plate are relatively moved while being rubbed with each other, thereby being superimposed on the coating surface. The oxide is squeezed out, and the brazing material coating is united in a state where the oxide and air bubbles are not caught. Thereafter, the brazing material is cooled and solidified to perform brazing.

JP-A-6-114549

  By the way, it has been found that in the conventional method for bonding a sputtering target, the bonding between the target material and the backing plate is not sufficient, and the target material may peel off during sputtering. As a result of intensive studies, the present inventor has found that, in the conventional method, the ratio of the area (joining area) actually joined to the area of the area (joining area) where the target material and the backing plate are to be joined (joining rate) ) Is small and the area where the area is the largest (maximum defect area) is large among the areas where the bonding material does not exist (unbonded areas) located between the target material and the backing plate. It has been found that there is a relationship between the joining rate and the maximum defect area and the peeling of the target material.

  Therefore, an object of the present invention is to provide a sputtering target capable of realizing a sputtering target in which the target material is not easily peeled off during sputtering, a method of joining the target material and the backing plate, and a method of manufacturing the sputtering target.

In order to solve the above problems, one embodiment of the sputtering target is:
Backing plate,
A target material joined via a joining material to a joining region of the backing plate (a region where the target material in the backing plate is to be joined),
The joining area of the joining portion (joined portion) between the target material and the backing plate is 97% or more with respect to the area of the joining region,
The maximum defect area of the unjoined portion between the target material and the backing plate is 0.6% or less with respect to the area of the joined region.

  According to the embodiment, it is possible to manufacture a sputtering target in which the joining rate can be improved, the maximum defect area can be reduced, and the target material is hardly peeled off.

  In one embodiment of the sputtering target, the length of the target material is 1000 mm or more and 4000 mm or less.

  According to the above-described embodiment, it is possible to manufacture a sputtering target in which a target material is hardly peeled even in a long sputtering target.

Further, one embodiment of a method of joining the target material and the backing plate includes:
A method of joining a target material and a backing plate with a joining material,
Applying a bonding material to a region (bonding region) of the main surface of the backing plate where the target material is to be bonded;
An edge (first edge) of the target material is opposed to the first edge in the bonding area of the backing plate in a first direction from a first edge of the bonding area of the backing plate; Sliding the target material along the main surface of the backing plate in the first direction so as to move to a position beyond the edge;
Sliding the target material along the main surface of the backing plate in a second direction opposite to the first direction to move the target material to coincide with the bonding area of the backing plate. Prepare.
Hereinafter, sliding the target material in the first direction and moving it is also referred to as “slide”, and sliding the target material in the second direction and moving it is also referred to as “reverse”.

  According to the above embodiment, the target material is made to coincide with the joining region of the backing plate by sliding the target material in the first direction with respect to the backing plate and then reversely moving the target material in the second direction. Thereby, in joining the target material and the backing plate, the joining rate can be improved, and the size of the maximum defect area having the largest area among the unjoined portions can be reduced. Therefore, a sputtering target from which the target material is not easily peeled can be manufactured.

In one embodiment of the method of joining the target material and the backing plate,
The target material and the backing plate are formed to be long,
The edge of the target material is formed along a longitudinal direction of the target material,
The first edge and the second edge of the joining region of the backing plate are formed along a longitudinal direction of the backing plate, and are opposed in a short direction of the backing plate,
The target material is slid with respect to the backing plate in the short direction of the backing plate and moved.

  According to the embodiment, in the long target material and the backing plate, the moving distance of the target material with respect to the backing plate can be reduced, and the working time can be shortened.

In one embodiment of the method of joining the target material and the backing plate,
Prior to the applying step of the bonding material, comprises a step of arranging a plurality of wires on the main surface of the backing plate,
In the movement of the target material in the first direction and the second direction, the target material is slid and moved on the wire.

  According to the embodiment, since the target material slides on the wire, the target material is maintained while the surface (bonding surface) to be bonded of the target material and the surface (bonding surface) to be bonded of the backing plate are kept substantially parallel. Can be easily moved, so that the joining rate can be improved. Further, since the wire functions as a spacer, the thickness of the bonding layer between the target material formed by the bonding material and the backing plate can be made constant.

  In one embodiment of the method for joining a target material and a backing plate, the diameter of the wire is 0.05 mm or more and 0.5 mm or less.

  According to the above-described embodiment, it is possible to prevent wire breakage and prevent uneven thickness of the bonding layer formed by the bonding material.

  In one embodiment of the method of joining the target material and the backing plate, the joining of the backing plate is performed between the moving the target material in the first direction and the moving the target material in the second direction. Refilling the first edge side of the region with a bonding material.

  According to the embodiment, since the joining material is replenished to the first edge side of the joining region of the backing plate, the joining material can be supplemented to the first edge side of the joining region where the joining material is likely to be insufficient, and the joining rate is further improved. The maximum defect area can be further reduced.

  In one embodiment of the method of joining a target material and a backing plate, in the step of moving the target material in the first direction, the edge (first end edge) of the target material is connected to the backing plate by the backing plate. When moving to a position beyond the second edge of the bonding area, the first direction from the second edge of the bonding area of the backing plate to the edge (first edge) of the target material. Assuming that the distance is A and the width of the bonding region in the first direction is W, 0.03 ≦ A / W <1.0.

  According to the embodiment, the joining rate can be improved and the maximum defect area can be reduced while reducing the moving distance of the target material with respect to the backing plate.

  In one embodiment of the method of joining a target material and a backing plate, in the step of moving the target material in the first direction, the edge (first end edge) of the target material is connected to the backing plate by the backing plate. When disposed on the first edge side of the bonding area, the distance in the first direction from the first edge of the bonding area of the backing plate to the edge (first edge) of the target material is B. When the width of the bonding region in the first direction is W, 0 ≦ B / W <2.0.

  According to the embodiment, the moving distance of the target material with respect to the backing plate can be reduced, or the target material can be slid after being placed on the backing plate, so that the joining rate can be improved, and the size of the maximum defect area can be improved. Can be reduced.

  In one embodiment of the method for manufacturing a sputtering target, the sputtering method is performed by bonding the target material and the backing plate using the bonding method.

  According to the embodiment, in joining the target material and the backing plate, the joining ratio can be improved, and the size of the maximum defect area having the largest area among the unjoined portions can be reduced. Therefore, a sputtering target from which the target material is not easily peeled can be manufactured.

  ADVANTAGE OF THE INVENTION According to the sputtering target of this invention, the method of joining a target material and a backing plate, and the manufacturing method of a sputtering target, the sputtering target which a target material does not peel easily can be manufactured.

It is explanatory drawing which shows one Embodiment of the method of joining the target material and the backing plate of this invention. It is explanatory drawing which shows one Embodiment of the method of joining the target material and the backing plate of this invention. It is explanatory drawing which shows one Embodiment of the method of joining the target material and the backing plate of this invention. It is explanatory drawing which shows one Embodiment of the method of joining the target material and the backing plate of this invention. It is explanatory drawing which shows one Embodiment of the method of joining the target material and the backing plate of this invention. FIG. 4 is a simplified cross-sectional view showing a state where no bonding material exists in a bonding layer existing between a target material and a backing plate. FIG. 4 is a simplified cross-sectional view showing a state where no bonding material exists in a bonding layer existing between a target material and a backing plate. It is a simplified diagram showing the state of the joining material between the target material and the backing plate of the sputtering target of the present invention. It is a simplified diagram showing the state of the joining material between the target material and the backing plate of the sputtering target of the comparative example.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(Embodiment)
1A to 1E are explanatory views showing one embodiment of a method of joining a target material and a backing plate (hereinafter, referred to as a “joining method”) according to the present invention. As shown in FIGS. 1A to 1E, this method is a method of joining a target material 2 and a backing plate 3 with a joining material 4.

  As shown in FIG. 1A, a target material 2 and a backing plate 3 are prepared. The target material 2 is formed in a long plate shape. The length of the target material 2 in the long side direction is, for example, 1000 mm or more and 4000 mm or less, preferably 1500 mm or more and 3500 mm or less, more preferably 2000 mm or more and 3200 mm or less, and still more preferably 2200 mm to 3000 mm or less. The length of the target material 2 in the short side direction is, for example, 100 mm or more and 2000 mm or less, preferably 120 mm or more and 1000 mm or less, more preferably 130 mm or more and 500 mm or less, and still more preferably 150 mm or more and 300 mm or less. The length in the long side direction and the length in the short side direction may be the same or different. The thickness of the target material 2 is, for example, 5 mm or more and 40 mm or less, preferably 10 mm or more and 30 mm or less, and more preferably 12 mm or more and 25 mm or less. According to the present invention, even when a target material for a large-sized flat panel display is used, it is possible to realize an improvement in the bonding rate and a reduction in the maximum defect area.

  Further, the aspect ratio (length in the long side direction / length in the short side direction) of the length in the long side direction and the length in the short side direction of the sputtering target is 1 or more and 30 or less, preferably 5 or more and 25 or less. And more preferably 6 or more and 20 or less, further preferably 7 or more and 18 or less, and particularly preferably 8 or more and 15 or less. According to this, although the sputtering target has an elongated shape, the effect of the reverse step can be easily exerted, a sputtering rate is high, and a sputtering target having a small maximum defect area can be manufactured.

  The target material 2 has a sputter surface 2a on the upper surface. The target material 2 has a first edge 21 and a second edge 22 corresponding to long sides when viewed from above. The first edge 21 and the second edge 22 are formed along the longitudinal direction of the target material 2, and the first edge 21 and the second edge 22 face each other in the short direction of the target material 2. Be placed.

  The target material 2 has a surface (bonding surface) to be bonded to the backing plate on the back side of the sputtering surface 2a serving as the upper surface. The size of the bonding surface is usually substantially the same as the size of the target material 2, but the burrs generated at the bonding surface during machining and the corners that cause abnormal discharge are removed. It may be smaller than the area (the length in the long side direction × the length in the short side direction, or the area in the plan view when there is an R portion). The area of the bonding surface may be usually 95% or more, preferably 98% or more, more preferably 99% or more of the area of the target material 2.

  During sputtering of the target material 2, an inert gas ionized by sputtering collides with the sputtering surface 2a. The target atoms contained in the target material 2 are bombarded from the sputtering surface 2a hit by the ionized inert gas. The struck-out atoms are deposited on a substrate disposed to face the sputtering surface 2a, and a thin film is formed on the substrate.

  The material for forming the target material 2 is not particularly limited as long as the material is made of a ceramic or a sintered body such as a metal, an alloy, an oxide, or a nitride that can be generally used for film formation by a sputtering method. The target material may be appropriately selected according to the application and purpose. For example, a material selected from the group consisting of metals such as aluminum, copper, chromium, iron, tantalum, titanium, zirconium, tungsten, molybdenum, niobium, indium, silver, cobalt, ruthenium, platinum, palladium, nickel, and alloys thereof. Alternatively, it can be manufactured from tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), or an In—Ga—Zn-based composite oxide (IGZO). The material constituting the target material 2 is not limited to these. For example, as a material of the target material 2 for an electrode or a wiring material, Al or an Al alloy is preferable, for example, Al having a purity of 99.99% or more, more preferably 99.999% or more, It is particularly preferred to use alloys (Al-Cu, Al-Si, Al-Cu-Si). Since high-purity Al has a relatively large linear thermal expansion coefficient, it is likely to be warped by heat received during sputtering and to be easily peeled off from the backing plate. However, according to the present invention, the joining rate is improved and the maximum defect area is reduced. And peeling from the backing plate can be prevented.

  The backing plate 3 is formed in a long plate shape. The length of the backing plate 3 in the long side direction is, for example, 1000 mm or more and 4500 mm or less, preferably 1500 mm or more and 4000 mm or less, more preferably 2000 mm or more and 3500 mm or less, and still more preferably 2500 mm or more and 3200 mm or less. The length of the backing plate 3 in the short side direction is, for example, 100 mm or more and 2000 mm or less, preferably 150 mm or more and 1200 mm or less, more preferably 180 mm or more and 750 mm or less, and still more preferably 200 mm or more and 350 mm or less. Here, one direction of the short direction of the backing plate 3 is defined as a first direction D1, and the other direction of the short direction of the backing plate 3 is defined as a second direction D2 opposite to the first direction D1.

  The backing plate 3 has a bonding area 30 (shown by hatching) on the main surface 3a of the upper surface. The joining region 30 is a region where the target material 2 is to be joined. The shape of the joining region 30 corresponds to the shape of the target material 2. That is, the size of the bonding region 30 is substantially the same as the size of the bonding surface of the target material 2, preferably, the size of the target material 2.

  The joining region 30 has a first edge 31 and a second edge 32 corresponding to long sides when viewed from above. The first edge 31 and the second edge 32 are formed along the longitudinal direction of the backing plate 3, and the first edge 31 and the second edge 32 face each other in the short direction of the backing plate 3. Be placed. The second edge 32 is located in the first direction D1 of the first edge 31.

  The backing plate 3 is made of a conductive material, and is made of a metal or an alloy thereof. Examples of the metal include copper, copper alloy, aluminum, aluminum alloy, titanium, and SUS.

  The joining surface of the target material 2 and the joining region 30 of the backing plate 3 are preferably flat, and have a flatness of 1 from the viewpoint of easily sliding or reversing the target material 2 and reducing the maximum defect area. 0.0 mm or less, preferably 0.5 mm or less, more preferably 0.3 mm or less. The flatness is a numerical value indicating the smoothness (uniformity) of a plane, and refers to the degree of deviation of a plane feature from a geometrically correct plane. In addition, from the viewpoint of preventing the flow of the bonding material on the bonding region 30 of the backing plate 3 during bonding, the backing plate 3 only has to have the main surface 3a of the upper surface and the back surface thereof substantially parallel, preferably parallel. From the viewpoint of easily applying a constant force to the target material 2 when the target material 2 is slid or reversed, the target material 2 only needs to have a substantially parallel, preferably parallel, sputter surface 2a on the upper surface and a bonding surface on the back surface. .

The bonding step is performed while the target material 2, the backing plate 3, and the bonding material 4 are heated. As shown in FIG. 1B, the bonding material 4 is applied to the entire bonding region 30 of the backing plate 3. The amount of the bonding material 4 to be applied is 1.5 × 10 ⁻⁶ kg / mm ² or more, preferably 2.5 × 10 ⁻⁶ kg / mm ² or more, and more preferably 4.5 × 10 ⁻⁶ kg / mm 2. ² or more, more preferably 10 × 10 ⁻⁶ kg / mm ² or more, still more preferably 14 × 10 ⁻⁶ kg / mm ² or more. The upper limit is not particularly limited, but is preferably 50 × 10 ⁻⁶ kg / mm ² or less, more preferably 35 × 10 ⁻⁶ kg / mm ² or less, and still more preferably 25 × 10 6 ⁻⁶ kg / mm ² or less. The joining material 4 is made of, for example, a metal having a low melting point (for example, 723 K or less) such as solder or brazing material, and the material of the solder is, for example, indium, tin, zinc, lead, silver, copper, bismuth, cadmium, antimony, or the like. Or an alloy thereof, for example, In material, In-Sn material, Sn-Zn material, Sn-Zn-In material, In-Ag material, Sn-Pb-Ag material, Sn-Bi material, Sn- Ag-Cu material, Pb-Sn material, Pb-Ag material, Zn-Cd material, Pb-Sn-Sb material, Pb-Sn-Cd material, Pb-Sn-In material, Bi-Sn-Sb material, In general, it is preferable to use a solder material such as In or In alloy, Sn or Sn alloy, which has a low melting point. The joining is performed at a temperature equal to or higher than the melting point of the joining material 4, preferably 140 ° C. or more, more preferably 150 ° C. or more and 300 ° C. or less, and the viscosity of the molten joining material 4 is 0.5 mPa · s or more. , Preferably not less than 1.0 mPa · s, more preferably not less than 1.5 mPa · s, and not more than 5 mPa · s, preferably not more than 3 mPa · s, and more preferably not more than 2.5 mPa · s. And the maximum defect area can be reduced. Before joining the target material 2 and the backing plate 3, the joining surface of the target material 2 with the backing plate 3, and the joining surface of the backing plate 3 with the target material 2, are used to improve the wettability with the joining material 4. A pre-process (metallization process) for improvement can be performed. For the pre-treatment, rough surface processing such as polishing or grinding, hairline processing, graining processing, and metallizing processing can be performed, and a polished surface, a ground surface, and a hairline are formed on the respective joining surfaces of the target material 2 and the backing plate 3. An uneven surface such as a surface or a textured surface or a metallized layer can be provided. For example, the polishing process can be performed manually using a polishing material obtained by applying abrasive grains to paper or a fiber base material, or using a polishing machine provided with the polishing material. The metallizing process can be performed by applying a metallizing material to the joint surface and performing ultrasonic irradiation. The metallizing material can be selected from the same materials as the bonding material 4, and for example, an In material and a Sn—Zn material can be used. The thickness of the metallized layer is 1 μm or more and 100 μm or less, and if it is within this range, it is easy to ensure wettability with the bonding material 4 and to improve the bonding rate. A portion where the target material 2 and the backing plate 3 are not bonded may be masked with a heat-resistant tape in advance, so that adhesion of the bonding material 4 and formation of a metallized layer can be prevented.

  Then, as shown in FIG. 1C, the first edge 21 of the target material 2 is placed on the first edge 31 side of the bonding area 30 of the backing plate 3. At this time, preferably, the first edge 21 of the target material 2 is arranged so as to overlap the bonding region 30.

  As shown in FIG. 1D, the first edge 21 of the target material 2 then moves from the first edge 31 of the bonding area 30 of the backing plate 3 to the second edge 32 of the bonding area 30 of the backing plate 3. The target material 2 is slid in the first direction D1 along the main surface 3a of the backing plate 3 so as to move to a position exceeding the position.

  As shown in FIG. 1E, thereafter, the target material 2 is slid and moved along the main surface 3a of the backing plate 3 in the second direction D2 so that the target material 2 matches the bonding region 30 of the backing plate 3. After that, the position of the target material 2 and the backing plate 3 is precisely aligned, and the joined body between the target material 2 and the backing plate 3 is cooled in a state where both are fixed by placing a weight, or being sandwiched between a vice, a vise, and a clamp. Then, the bonding material 4 is solidified. Thus, the sputtering target 1 is manufactured by joining the target material 2 and the backing plate 3 with the joining material 4.

  According to the joining method, the target material 2 is made to coincide with the joining area 30 of the backing plate 3 by sliding the target material 2 with respect to the backing plate 3 in the first direction D1 and then reversing the target material 2 in the second direction D2. ing. In this way, by reversing not only the target material 2 but also the slide, the joining material 4 can be pulled back in the second direction D2 by the surface tension together with the reverse of the target material 2, and the gap between the target material 2 and the backing plate 3 can be reduced. The space where the joining material 4 does not exist can be reduced, and the unjoined portion can be reduced.

Therefore, in joining the target material 2 and the backing plate 3, the joining rate can be improved, and the maximum defect area can be reduced.
The bonding ratio refers to a ratio of a bonding area of a bonding portion between the target material 2 and the backing plate 3 to an area of the bonding region 30.
Specifically, the bonding area refers to the entire area of a portion where a region where no bonding material exists is not detected when viewed from the thickness direction of the bonding layer between the target material 2 and the backing plate 3.
The maximum defect area refers to the area of the portion having the largest area among the portions located between the target material 2 and the backing plate 3 and having no bonding material 4. Here, the portion where the bonding material 4 does not exist (unbonded portion) refers to a region where the bonding material does not exist in the thickness direction of the bonding layer, that is, a space or a foreign material other than the bonding material such as an oxide of the bonding material. It means a location to be detected, and may include not only the entire joining layer in the thickness direction but also a case where there is no joining material in a part. For example, as shown in FIG. 2A, in the bonding layer 6 existing between the target material 2 and the backing plate 3, the bonding material 4 does not exist in a part of the bonding layer 6 in the thickness direction (vertical direction in the drawing). A space S may be present, or, as shown in FIG. 2B, the bonding layer 6 existing between the target material 2 and the backing plate 3 has a thickness direction (a vertical direction in the drawing) of the bonding layer 6. A space S in which the bonding material 4 does not exist may exist as a whole. The region where the bonding material does not exist can be detected by a measurement method described later. For example, when ultrasonic flaw detection is used, if there is a space in the bonding layer where no bonding material is present, the incident ultrasonic wave is reflected at the interface, so that a defective portion can be recognized.

  Therefore, according to the present invention, since the joining rate between the target material 2 and the backing plate 3 can be increased and the maximum defect area can be reduced, a portion having low joining strength is hardly formed, and the target material 2 is peeled. A difficult sputtering target 1 can be manufactured.

  As described above, in the present invention, by focusing on both the joining rate and the maximum defect area, it has been found that the target material 2 is hardly peeled off during sputtering. More specifically, with respect to the joining rate, when the joining rate increases, the area where the joining material 4 does not exist can be reduced, and the target material 2 is less likely to peel.

  On the other hand, regarding the maximum defect area, when the maximum defect area is large, a large defect is locally generated, electric and heat conduction in that part is deteriorated, heat is concentrated in that part, and bonding is performed. When the material 4 is melted, the target material 2 is easily peeled off. For this reason, when the maximum defect area is small, a large defect does not occur locally, and the target material 2 is hardly peeled off.

  According to the joining method, the target material 2 is slid with respect to the backing plate 3 in the short direction of the backing plate 3 and moved. According to this, in the long target material 2 and the backing plate 3, the moving distance of the target material 2 with respect to the backing plate 3 can be reduced, and the working time can be shortened.

  Preferably, before the step of applying the bonding material 4 (see FIG. 1B), a plurality of wires 5 are arranged on the main surface 3a of the backing plate 3, as shown in FIG. 1A. The material of the wire 5 is, for example, stainless steel or copper. Specifically, the wires 5 are arranged in the bonding region 30 so as to extend in the first direction D1, and the plurality of wires 5 are arranged at intervals in a direction orthogonal to the first direction D1. Then, in the movement of the target material 2 in the first direction D1 and the second direction D2, the target material 2 is slid on the wire 5 and moved. According to this, since the target material 2 slides on the wire 5, the target material 2 can be easily moved. Furthermore, by using the wire 5 as a spacer, the thickness of the bonding layer formed by the bonding material 4 can be made constant. The thickness of the bonding layer is usually 0.03 mm or more and 1.5 mm or less, preferably 0.05 mm or more and 1 mm or less, more preferably 0.08 mm or more and 0.5 mm or less, and still more preferably 0.1 mm or more and 0.35 mm or less.

  Preferably, the diameter of the wire 5 is 0.05 mm or more and 0.5 mm or less, and more preferably 0.1 mm or more and 0.3 mm or less. According to this, breakage of the wire 5 is less likely to occur, and variation in the thickness of the bonding layer can be reduced.

Preferably, between the step of moving the target material 2 in the first direction D1 (see FIG. 1D) and the step of moving the target material 2 in the second direction D2 (see FIG. 1E), the first region of the joining region 30 of the backing plate 3 is moved. The joining material 4 is replenished to the edge 31 side. Specifically, in the state shown in FIG. 1D, the bonding material 4 is added to a portion of the bonding region 30 that is not covered with the target material 2. According to this, since the joining material 4 is replenished to the first edge 31 side of the joining region 30 of the backing plate 3, the first joining region 30 in which the joining material 4 is likely to run short with the movement of the target material 2. The joining material 4 can be replenished on the edge 31 side, the joining rate can be further improved, and the maximum defect area can be further reduced. The amount of the joining material 4 to be replenished is preferably 0.5 × 10 ⁻⁶ kg / mm ² or more, more preferably 0.8 × 10 ⁻⁶ kg / mm ² or more, and still more preferably 1.0 × 10 ^−6. kg / mm ² or more. The upper limit is not particularly limited, but is preferably 20 × 10 ⁻⁶ kg / mm ² or less, more preferably 10 × 10 ⁻⁶ kg / mm ² or less, and still more preferably 7.0 from the viewpoint of workability in the joining step. × 10 ⁻⁶ kg / mm ² or less.

  Preferably, in the step of moving the target material 2 in the first direction D1, as shown in FIG. 1D, a position where the first edge 21 of the target material 2 exceeds the second edge 32 of the bonding area 30 of the backing plate 3 , When the distance in the first direction D1 from the second edge 32 of the joining region 30 of the backing plate 3 to the first edge 21 of the target material 2 is A, the width of the joining region 30 in the first direction D1 Where W is 0.03 ≦ A / W <1.0, preferably 0.05 ≦ A / W ≦ 0.8, and more preferably 0.06 ≦ A / W ≦ 0.6. Specifically, 10 mm ≦ A ≦ 150 mm, preferably 12 mm ≦ A ≦ 120 mm, and preferably 150 mm ≦ W ≦ 300 mm. According to this, the joining rate can be improved and the maximum defect area can be reduced while reducing the moving distance of the target material 2 with respect to the backing plate 3.

  Preferably, in the moving step of the target material 2 in the first direction D1, as shown in FIG. 1C, the first edge 21 of the target material 2 is arranged on the first edge 31 side of the bonding area 30 of the backing plate 3. Then, the distance in the first direction D1 from the first edge 31 of the bonding area 30 of the backing plate 3 to the first edge 21 of the target material 2 is B, and the width of the bonding area 30 in the first direction D1 is W Then, 0 ≦ B / W <2.0, preferably 0 ≦ B / W ≦ 1.5, more preferably 0.03 ≦ B / W ≦ 1.2, and still more preferably 0.10 ≦ B / W. ≦ 1.0. Specifically, 0 mm ≦ B ≦ 300 mm, preferably 5 mm ≦ B / W ≦ 200 mm, and more preferably 150 mm ≦ W ≦ 300 mm. According to this, the joining rate can be improved and the maximum defect area can be reduced while reducing the moving distance of the target material 2 with respect to the backing plate 3.

  The speed of movement (slide) of the target material 2 in the first direction D1 and movement (reverse) of the target material 2 in the second direction D2 is not more than 100 mm / sec from the viewpoint of preventing unnecessary movement and escape of the bonding material placed in the bonding region. It is preferably 50 mm / sec or less, more preferably 30 mm / sec or less. The lower limit is not particularly limited, but is 1 mm / sec or more, preferably 5 mm / sec or more from the viewpoint of productivity.

  At the stage where the edge of the target material 2 is arranged on the first edge side of the joining region of the backing plate and / or at the stage where the movement (sliding) of the target material 2 in the first direction D1 is finished, It is preferable to provide a step of applying vibration from the upper surface of the substrate to remove air that may be present in the bonding layer. As a means for applying vibration, a method of tapping the upper surface of the target material lightly or a method of applying vibration in a direction parallel to the upper surface of the target material 2 can be performed. The range in which the vibration is applied is such that when the edge of the target material 2 is arranged on the first edge side of the bonding region of the backing plate, the entire bonding layer between the target material and the backing plate (the target material rides). When the movement (slide) of the target material 2 in the first direction D1 is completed, it is preferable to perform the movement (reverse) operation in the second direction D2. It is preferable that the vibration is applied in a direction from the center to the outer periphery of the bonding layer (the bonding region where the target material rides) between the target material and the backing plate. Thereby, since air existing in the bonding layer can be removed, the bonding ratio can be improved and the maximum defect area can be reduced. In particular, when the edge of the target material 2 is arranged on the first edge side of the bonding area of the backing plate, the bonding layer (the bonding area on which the target material rides) between the target material and the backing plate is formed. Since there is a high possibility that an air pocket exists, the provision of the air removal step can further improve the joining rate and reduce the maximum defect area.

  Next, a method for manufacturing the sputtering target 1 will be described. As described above, the sputtering method is performed by bonding the target material and the backing plate using the bonding method.

  In the manufacturing method of the present invention, the target material can be processed into a substantially plate shape, but the method for processing into the plate shape is not particularly limited. For example, a target material made of a metal material is obtained by subjecting a rectangular parallelepiped, cylindrical, or columnar target material obtained by melting and casting to plastic working such as rolling, extrusion, or forging, followed by cutting or grinding. By performing mechanical processing (cutting, milling, end milling, etc.) such as polishing, a target material having a desired size and surface state can be manufactured. The rolling process is described in, for example, Japanese Patent Application Laid-Open No. 2010-132942 and International Publication No. 2011/034127. The extrusion process is described in, for example, JP-A-2008-156694. Forging processing is described in, for example, JP-A-2017-150015, JP-A-2001-240949, or Aluminum Technology Handbook (edited by the Japan Light Metal Association Aluminum Technology Handbook Editing Committee, Karos Publishing, New Edition, issued November 18, 1996). It is described in. Using the joining method of the present invention, a machined plate-shaped target material is joined to a backing plate to produce a sputtering target. Further, as the target material, a target material which is machined to a predetermined size may be used. In a manufacturing process of the sputtering target 1, an abnormality occurs in bonding with a backing plate, which deviates from the product specifications. The backing plate may be removed from the sputtering target, and the target material may be obtained by further removing the bonding material. Note that, if necessary, the surface of the joined sputtering target may be subjected to finishing by cutting or polishing.

  In the method for manufacturing a sputtering target of the present invention, since the bonding method of the present invention is used, a sputtering target with improved quality can be obtained.

  Next, the sputtering target 1 joined by the joining method will be described.

  As shown in FIG. 1E, the sputtering target 1 has a backing plate 3 and a target material 2 joined to a joining region 30 of the backing plate 3 via a joining material 4.

  FIG. 3A is a simplified diagram showing a state of the bonding material 4 between the target material 2 of the sputtering target 1 and the backing plate 3. In FIG. 3A, a defective portion (unjoined portion) 10 where the joining material 4 does not exist in the joining region 30 is indicated by hatching. The measurement of the defect portion 10 can be performed by using, for example, ultrasonic flaw detection measurement or transmission X-ray observation, but when the area of the bonding region is large, it is preferable to use ultrasonic flaw detection measurement. As the ultrasonic flaw detection apparatus, FS LINE and FS LINE Hybrid manufactured by Hitachi Power Solutions Co., Ltd., and a phased array ultrasonic flaw detection imaging apparatus PDS and an ultrasonic flaw detection imaging apparatus ADS71000 manufactured by KJTD can be used. In addition, when determining the bonding rate and the maximum defect area by ultrasonic inspection measurement, a pseudo defect sample having a flat bottom hole of a predetermined size is used, and ultrasonic inspection measurement conditions for recognizing a reflected wave from a defective portion are used. Adjustments are required. Since the propagation speed of the ultrasonic wave varies depending on the material, the pseudo defect sample is preferably made of the same material as the material on the ultrasonic wave incident side of the sputtering target 1 in order to equalize the measurement sensitivity and the condition surface. Further, it is preferable that the distance between the ultrasonic incident surface of the pseudo defect sample and the bottom surface of the flat bottom hole is equal to the distance between the ultrasonic incident surface of the sputtering target 1 and the bonding layer.

As shown in FIG. 3A, the area of the portion where the defective portion 10 is not detected between the target material 2 and the backing plate 3 is 97% or more of the area of the bonding region 30. That is, the joining ratio is 97% or more, preferably 98% or more, and more preferably 98.5% or more. In addition, the maximum defect area of the defect portion 10 in the bonding layer between the target material 2 and the backing plate 3 is 2% or less, preferably 1% or less, more preferably 0% with respect to the area of the bonding region 30. 0.6% or less, more preferably 0.3% or less, still more preferably 0.1% or less, particularly preferably less than 0.05%. For example, when the area of the bonding region 30 is 200 mm × 2300 mm, the maximum defect area is 2000 mm ² or less.

  According to the present invention, it is possible to manufacture the sputtering target 1 in which the joining rate can be improved, the maximum defect area can be reduced, and the target material 2 is hardly peeled off. Preferably, the length of the target material 2 is 1000 mm or more and 4000 mm or less, and the sputtering target 1 in which the target material 2 is hard to peel off can be manufactured even in the long sputtering target 1.

The upper limit of the joining rate is 100% at the maximum, but the viewpoint that the target material is easily peeled when a backing plate is removed from a sputtering target that has become out of specification due to an abnormality at the time of joining or a sputtering target used by sputtering. Therefore, the bonding ratio is preferably 99.99% or less, more preferably 99.95% or less, and further preferably 99.90% or less. In addition, by applying heat to the sputtering target so as to have a temperature equal to or higher than the melting point of the bonding material used for bonding, while softening or melting the bonding layer, physically breaking the bonding layer as necessary, From the target material.
The lower limit of the ratio of the maximum defect area to the area of the bonding region 30 is not particularly limited, but is preferably 0.001% or more, and preferably 0.003%, from the viewpoint of further suppressing the warping of the sputtering target due to heat generated during sputtering. As described above, the content is more preferably 0.005% or more, and further preferably 0.008% or more. When the lower limit value of the ratio of the maximum defect area is equal to or more than the above, the deformation of the target material caused by heat during sputtering is alleviated by the local defect portion, and the warpage of the sputtering target is reduced.

  On the other hand, FIG. 3B shows the sputtering target 100 of the comparative example in which the target material and the backing plate are joined only by sliding the target material in the first direction D1, and the gap between the target material and the backing plate is shown. This shows the state of the joining material. As shown in FIG. 3B, as compared with FIG. 3A, the ratio of the defective portions 10 is large, the joining rate is small, and the maximum defect area of the defective portions 10 is large. As described above, when only the slide of the target material is used, the bonding state between the target material and the backing plate is deteriorated, and as a result, the target material is easily peeled. In particular, if the target material is a long target or a sputtering target having a large bonding area, the target material is more easily peeled.

  In a preferred embodiment of the sputtering target of the present invention, a wire may be provided between the target material and the backing plate, that is, in the bonding layer. By having the wire in the bonding layer, the thickness of the bonding layer can be easily ensured and the thickness of the bonding layer can be made more constant, so that the bonding rate of the sputtering target 1 can be increased and the maximum defect area can be reduced. It is possible to manufacture the sputtering target 1 in which 2 is not easily peeled.

(Example 1)
A rolled plate made of high-purity Al having a purity of 99.999% is prepared, and cut by a double-column machining center to produce a target material of 200 mm × 2300 mm × t16 mm (the area of the joining region is 4.5 × 10 ⁵ mm ² ). Was prepared, and a backing plate composed of oxygen-free copper having a purity of 99.99% was prepared. The width W of the joining region in the first direction D1 (so-called target material width) W in the step of moving the target material was 200 mm.

  The target material and the backing plate were heated on a hot plate to a temperature equal to or higher than the melting point of the bonding material.

  The Sn-Zn-In alloy material was melted on the bonding surface of the target material, and the In material was melted on the bonding surface of the backing plate, and the metallizing process was performed on the bonding surface of both materials using an ultrasonic soldering iron. After the metallizing treatment, the Sn—Zn—In alloy material, the oxide of the In material, excess Sn—Zn—In alloy material, and the In material on the joining surface of the target material and the joining surface of the backing plate were removed with a spatula. .

  Ten SUS wires having a diameter of 0.2 mm are arranged at substantially equal intervals in a direction perpendicular to the longitudinal direction of the backing plate on the joint surface of the metalized backing plate. Was applied on the bonding surface. The amount of the In material for bonding applied on the bonding surface from above the SUS wire was 7.80 kg.

  Change the direction of the target material so that the joining surface of the target material faces the joining surface of the backing plate in parallel, and place the long side of the target material on the wire so that it overlaps the long side of the backing plate. Then, the target material was slid in the direction of the predetermined joining position. The target material is moved in the second direction D2 in the second direction D2 by sliding the target material in the second direction D2 so that the ratio A / W of the distance (overrun amount) A of the target material overrun from the predetermined joining position with respect to the target material width W is 0.1625. The head in the (reverse) direction was lightly tapped from above to blow out air.

  Thereafter, the target material was slid to a predetermined joining position. Fine adjustment of the target material position was performed so that the target material was at a predetermined bonding position, a weight was placed on the target material to fix the target material and the backing plate, and then the bonded body was cooled to produce a sputtering target.

  After the In material was solidified, a warp caused by a difference in linear expansion coefficient between the target material and the backing plate was corrected to obtain a target. The joining rate and the maximum defect area were measured with an ultrasonic flaw detector FS-LINE manufactured by Hitachi Power Solutions Co., Ltd.

  The measurement of the bonding ratio and the maximum defect area was performed in the following procedure. First, using a rolled plate made of high-purity Al having a purity of 99.999%, chamfering both surfaces of the rolled plate to form a parallel surface, and a flat bottom hole having a circle equivalent diameter (diameter) φ of 2 mm from one surface. , A pseudo-defect sample having a counterbore of φ6 mm was prepared. At this time, the distance from the sample surface having no holes to the flat bottom hole was set to be the same as the target material thickness.

  As a preparation before measurement, an ultrasonic flaw detector “I3-1006-TS-80 mm” (frequency: 10 MHz, focal length: 80 mm) was attached to the measurement device.

  Then, the pseudo-defect sample was set in the measuring apparatus, and the measurement was started by focusing on the counterbore. First, the counterbore was confirmed, and then the flat bottom hole was confirmed while focusing on the counterbore. Thereafter, the focus was on the flat bottom hole. Ultrasonic flaw detection (C scan) was performed in this state, and the sensitivity was adjusted so that the detected flat-bottom hole diameter matched the flat-bottom hole diameter of the pseudo-defect sample. ) Was 12 dB, the measurement pitch was 2 mm, and the defect level was 38. In this way, the sensitivity of the program was adjusted so that a reflection echo having a strength of 38 or more was detected as a defect.

  Next, the pseudo defect sample was taken out of the measuring device, and the bonded sputtering target was set on the measuring device such that the target material side was the upper surface. Set the height of the ultrasonic probe so that the height of the focal position of the program created with the pseudo defect sample is the bonding layer of the sputtering target, and set the scanning range of the ultrasonic probe so that the measurement field of view is the entire bonding surface. Ultrasonic testing (C scan) was performed on the joined sputtering targets. The ultrasonic wave was incident from the target material side.

  The obtained data was analyzed by the analysis program attached to the ultrasonic flaw detector, and the bonding rate and the maximum defect area information were obtained. Thereafter, surface finishing was performed by polishing or blasting.

  Table 1 shows the results of the sputtering targets joined as in Example 1.

(Examples 2 to 12)
The bonding material amount, the wire diameter, the bonding material type, the target material installation position B and the overrun amount A shown in Table 1 are used, and after the target material is installed on the bonding surface of the backing plate, the bonding layer between the target material and the backing plate ( Examples 2 to 12 were carried out in the same manner as in Example 1 except that substantially the entire surface of the contact portion and the joining region on which the target material was mounted) was lightly tapped from above to remove air in the joining layer. In Examples 2 to 12, the target material was slid in the first direction and then reversed in the second direction, as in Example 1.
(Example 13)
In Example 13, the joining surface of the backing plate was metallized with a Sn—Zn material, Sn—Zn (containing 9% Zn) was used as the joining material, and the air in the joining layer was not beaten out. A sputtering target was produced in the same manner as in Example 2, and the bonding ratio and the maximum defect area were determined.
(Comparative Example 1)
Comparative Example 1 was performed in the same manner as in Examples 2 to 12, except that the target material was only slid in the first direction, but was not reversed in the second direction.
(Comparative Example 2)
In Comparative Example 2, a sputtering target was produced under the conditions shown in Table 1 without sliding or reversing the target material or slamming the air and neither sliding nor reversing the target material.

  In Table 1, “the amount of the bonding material to be installed” refers to the amount of the bonding material applied to the bonding region 30 of the backing plate 3 in FIG. 1B. The “replenishment bonding material amount” refers to the amount of the bonding material replenished to the bonding region 30 of the backing plate 3 through which the target material has passed in FIG. 1D. The “wire type” in FIG. 1A refers to the type of the wire 5 installed in the joint region 30 of the backing plate 3 and uses stainless steel. “Wire diameter” refers to the diameter of the wire 5. The term “joining material type” refers to the material of the joining material, and uses solder made of In or Sn—Zn. The “target material installation position” refers to a position where the target material 2 is installed in FIG. 1C, and a first position from the first edge 31 of the bonding area 30 of the backing plate 3 to the first edge 21 of the target material 2. This is the distance B in the direction D1. “Air blow-out” refers to a stage in which the edge of the target material 2 is arranged on the first edge side of the joining region of the backing plate in FIG. 1C, and in FIG. 1D, the movement of the target material 2 in the first direction D1 ( After the slide is completed, the upper surface of the target material 2 is hit to release air between the target material 2 and the backing plate 3. The “target material overrun amount” refers to an amount of the target material 2 protruding from the bonding region 30, and in FIG. 1D, from the second edge 32 of the bonding region 30 of the backing plate 3 to the first edge of the target material 2. 21 is the distance A in the first direction D1 to 21. “Joining material replenishment” refers to whether to replenish the joining material.

As can be seen from Table 1, in Examples 1 to 13, the bonding ratio was 97% or more and the maximum defect area was 2000 mm ² or less (that is, the ratio of the maximum defect area to the area of the bonding region was 0.1%). 6% or less). In Examples 1 to 13, the target material was hard to peel off, and no peeling of the target material was confirmed even after use in a sputtering apparatus.

On the other hand, in Comparative Example 1, the joining rate was 90.70% and the maximum defect area was 11628 mm ² , and in Comparative Example 2, the joining rate was 96.27% and the maximum defect area was 96.27%. The area is 1948 mm ² . In Comparative Examples 1 and 2, the target material was easily peeled off.

  It should be noted that the present invention is not limited to the above-described embodiment, and design changes can be made without departing from the spirit of the present invention.

  In the above embodiment, the target material and the backing plate are formed to be long, but the target material and the backing plate may have the same length on the short side and the long side.

DESCRIPTION OF SYMBOLS 1 Sputtering target 2 Target material 2a Sputter surface 21 1st edge 22 2nd edge 3 Backing plate 3a Main surface 30 Joining area 31 1st edge 32 2nd edge 4 Bonding material 6 Bonding layer 5 Wire 10 Defect location D1 First direction D2 Second direction

Claims (8)

A method of joining a target material and a backing plate with a joining material,
A step of applying a bonding material to a bonding area on the main surface of the backing plate where the target material is to be bonded,
An edge of the target material extends from a first edge side of the joining region of the backing plate to a position exceeding a second edge facing the first edge in the joining region of the backing plate in a first direction. Moving the target material by sliding in the first direction along the main surface of the backing plate so as to move;
Sliding the target material along the main surface of the backing plate in a second direction opposite to the first direction to move the target material to coincide with the bonding area of the backing plate. A joining method. The target material and the backing plate are formed to be long,
The edge of the target material is formed along a longitudinal direction of the target material,
The first edge and the second edge of the joining region of the backing plate are formed along a longitudinal direction of the backing plate, and are opposed in a short direction of the backing plate,
The bonding method according to claim 1 , wherein the target material is slid relative to the backing plate in a short direction of the backing plate and moved. Prior to the applying step of the bonding material, comprises a step of arranging a plurality of wires on the main surface of the backing plate,
In the movement of the first direction and the second direction of the target material, the target material is moved by sliding on the wire bonding method according to claim 1 or 2. The joining method according to claim 3 , wherein the diameter of the wire is 0.05 mm or more and 0.5 mm or less. Between the step of moving the target material in the first direction and the step of moving the target material in the second direction, the method further includes a step of replenishing a bonding material on the first edge side of the bonding region of the backing plate. the bonding method according to any one of claims 1 4. In the moving step of the target material in the first direction, when the edge of the target material is moved to a position beyond the second edge of the bonding area of the backing plate, the bonding area of the backing plate is moved. 0.03 ≦ A / W <1 where A is the distance in the first direction from the second edge of the target material to the edge of the target material, and W is the width of the bonding region in the first direction. The bonding method according to any one of claims 1 to 5 , wherein the bonding method is 0.0. In the moving step of the target material in the first direction, when the edge of the target material is arranged on the first edge side of the bonding area of the backing plate, the second edge of the bonding area of the backing plate is When a distance in the first direction from one edge to the edge of the target material in the first direction is B, and a width of the bonding region in the first direction is W, 0 ≦ B / W ≦ 1.0 . the bonding method according to any one of claims 1 5. A method for manufacturing a sputtering target, comprising: bonding the target material and the backing plate using the bonding method according to any one of claims 1 to 7 to manufacture a sputtering target.

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