JP2024032987A - sputtering target - Google Patents

Abstract

An object of the present invention is to provide a sputtering target whose target material is difficult to peel 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 point between the target material and the backing plate is: 97% or more of the area of the bonding region, and a maximum defect area of a portion where there is no bonding material between the target material and the backing plate is 0.6% of the area of the bonding region. It is as follows. [Selection diagram] Figure 1C

Description

The present invention relates to sputtering targets.

As a conventional sputtering target bonding method, there is a method described in Japanese Patent Application Laid-Open No. 6-114549 (Patent Document 1). In this sputtering target bonding method, a molten brazing metal coating is formed on the target material and the backing plate, respectively, and the target material and the backing plate are moved relative to each other while rubbing against each other to overlap. The oxide is squeezed out, and the brazing metal coating is combined without entrapment of oxides or air bubbles, and then the brazing metal is cooled and solidified to perform brazing.

Japanese Patent Application Publication No. 6-114549

By the way, it has been found that in the conventional sputtering target bonding method, the bonding between the target material and the backing plate is insufficient, and there is a risk that the target material may peel off during sputtering. As a result of extensive studies, the present inventor found that in conventional methods, the ratio of the area where the target material and the backing plate are actually joined (joint area) to the area where the target material and backing plate should be joined (joint area) (joining rate ) is small and the area where the area is the largest (maximum defect area) is large among the areas where there is no bonding material (unbonded areas) located between the target material and the backing plate. We found that there is a relationship between the bonding rate, maximum defect area, and peeling of the target material.

Therefore, an object of the present invention is to provide a sputtering target whose target material is difficult to peel off during sputtering.

In order to solve the above problem, one embodiment of the sputtering target is as follows:
backing plate and
a target material bonded to a bonding region of the backing plate (a region of the backing plate where the target material is to be bonded) via a bonding material;
The joint area of the joint location (joined location) between the target material and the backing plate is 97% or more of the area of the joint region,
A maximum defect area of an unbonded portion between the target material and the backing plate is 0.6% or less with respect to the area of the bonding region.

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

Moreover, 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 embodiment, it is possible to manufacture a sputtering target in which the target material does not easily peel off even in the case of a long sputtering target.

Further, one embodiment of a method for joining a target material and a backing plate includes:
A method of joining a target material and a backing plate using a joining material, the method comprising:
applying a bonding material to a region (bonding region) where the target material is to be bonded on the main surface of the backing plate;
The edge (first edge) of the target material is a second edge opposite to the first edge in the bonding area of the backing plate in a first direction from the first edge side of the bonding area of the backing plate. sliding the target material in the first direction along the main surface of the backing plate so as to move the target material to a position beyond the edge;
sliding the target material in a second direction opposite to the first direction along the main surface of the backing plate to align the target material with the bonding area of the backing plate; Be prepared.
Hereinafter, sliding the target material in the first direction is also referred to as "slide", and sliding the target material in the second direction is also referred to as "reverse".

According to the embodiment, the target material is made to match the bonding area of the backing plate by sliding the target material in the first direction relative to the backing plate and then reversing it 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, which is the largest area among the unjoined parts, can be reduced. Therefore, it is possible to manufacture a sputtering target in which the target material is difficult to peel off.

Additionally, in one embodiment of the method of joining a target material and a backing plate,
The target material and the backing plate are formed in a long length,
The edge of the target material is formed along the longitudinal direction of the target material,
The first edge and the second edge of the bonding region of the backing plate are formed along the longitudinal direction of the backing plate and are opposed to each other in the lateral direction of the backing plate,
The target material is slid on the backing plate in the lateral direction of the backing plate.

According to the embodiment, in the case of a long target material and a 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.

Additionally, in one embodiment of the method of joining a target material and a backing plate,
A step of arranging a plurality of wires on the main surface of the backing plate before the step of applying the bonding material,
In moving the target material in the first direction and the second direction, the target material is moved by sliding on the wire.

According to the embodiment, since the target material slides on the wire, the target material is slid while the surface of the target material to be joined (joint surface) and the surface to be joined (joint surface) of the backing plate are kept substantially parallel. Since it can be easily moved, the bonding rate can be improved. Furthermore, since the wire functions as a spacer, the thickness of the bonding layer formed by the bonding material between the target material and the backing plate can be made constant.

Moreover, 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 embodiment, wire breakage can be prevented, and the thickness of the bonding layer formed by the bonding material can be prevented from becoming uneven.

In one embodiment of the method for joining a target material and a backing plate, the joining of the backing plate is performed 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 includes a step of replenishing a bonding material on the first edge side of the region.

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

Further, in an embodiment of the method for joining a target material and a backing plate, in the step of moving the target material in the first direction, the end edge (first end edge) of the target material is 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. When 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, it is possible to improve the bonding rate and reduce the maximum defect area while reducing the moving distance of the target material relative to the backing plate.

Further, in an embodiment of the method for joining a target material and a backing plate, in the step of moving the target material in the first direction, the end edge (first end edge) of the target material is 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. If the width of the bonding region in the first direction is W, then 0≦B/W<2.0.

According to the above embodiment, the moving distance of the target material relative to the backing plate can be reduced, and the target material can be placed on the backing plate and then slid, thereby improving the bonding rate and reducing the size of the maximum defect area. can be reduced.

Moreover, in one embodiment of the method for manufacturing a sputtering target, the target material and the backing plate are bonded using the bonding method to manufacture a sputtering target.

According to the embodiment, in joining the target material and the backing plate, the joining rate can be improved, and the size of the maximum defect area, which is the largest area among the unjoined parts, can be reduced. Therefore, it is possible to manufacture a sputtering target in which the target material is difficult to peel off.

According to the sputtering target of the present invention, a sputtering target whose target material is difficult to peel off can be manufactured.

It is an explanatory view showing one embodiment of a method of joining a target material and a backing plate of the present invention. It is an explanatory view showing one embodiment of a method of joining a target material and a backing plate of the present invention. It is an explanatory view showing one embodiment of a method of joining a target material and a backing plate of the present invention. It is an explanatory view showing one embodiment of a method of joining a target material and a backing plate of the present invention. It is an explanatory view showing one embodiment of a method of joining a target material and a backing plate of the present invention. FIG. 3 is a simplified cross-sectional view showing a state where no bonding material is present in the bonding layer existing between the target material and the backing plate. FIG. 3 is a simplified cross-sectional view showing a state where no bonding material is present in the bonding layer existing between the target material and the backing plate. FIG. 3 is a simplified diagram showing the state of the bonding material between the target material and the backing plate of the sputtering target of the present invention. FIG. 3 is a simplified diagram showing the state of a bonding material between a target material and a backing plate of a sputtering target of a comparative example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to illustrated embodiments.

(Embodiment)
FIGS. 1A to 1E are explanatory diagrams showing one embodiment of a method for joining a target material and a backing plate (hereinafter referred to as "joining method") of the present invention. As shown in FIGS. 1A to 1E, this method is a method in which a target material 2 and a backing plate 3 are bonded using a bonding material 4.

As shown in FIG. 1A, a target material 2 and a backing plate 3 are prepared. The target material 2 is formed into 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 even more preferably 2200 mm to 3000 mm. 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. Note that the length in the long side direction and the length in the short side direction may be the same or different. Further, 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. In the present invention, even when a target material for a large flat panel display is used, it is possible to improve the bonding rate and reduce the maximum defect area.

Further, the aspect ratio of the length in the long side direction and the length in the short side direction of the sputtering target (length in the long side direction/length in the short side direction) is 1 or more and 30 or less, preferably 5 or more and 25 or less. , more preferably 6 or more and 20 or less, still more preferably 7 or more and 18 or less, particularly preferably 8 or more and 15 or less. According to this, although the sputtering target has an elongated shape, it is possible to manufacture a sputtering target that easily exhibits the effect of the reverse process, has a high bonding rate, and has a small maximum defect area.

The target material 2 has a sputtering surface 2a on the upper surface. The target material 2 has a first edge 21 and a second edge 22 corresponding to the long sides when viewed from the top surface. 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 are formed facing each other in the lateral direction of the target material 2. Placed.

The target material 2 has a surface to be bonded to the backing plate (bonding surface) 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 size of the target material 2 is reduced by removing burrs that occur on the bonding surface during machining and by removing corners that may cause abnormal discharge. It may be smaller than the area (length in the long side direction x length in the short side direction, area in the plan view when it has an R section). The area of the bonding surface may be usually 95% or more, preferably 98% or more, and more preferably 99% or more of the area of the target material 2.

During sputtering of the target material 2, inert gas ionized by sputtering collides with the sputtering surface 2a. Target atoms contained in the target material 2 are ejected from the sputtering surface 2a with which the ionized inert gas collides. The ejected atoms are deposited on a substrate placed opposite to the sputtering surface 2a, and a thin film is formed on this substrate.

The material from which the target material 2 is made is not particularly limited as long as it is a material composed of ceramics or sintered bodies such as metals, alloys, oxides, and nitrides that can be normally used for film formation by sputtering method. The target material may be selected as appropriate depending on the use and purpose. For example, materials selected from the group consisting of metals such as aluminium, copper, chromium, iron, tantalum, titanium, zirconium, tungsten, molybdenum, niobium, indium, silver, cobalt, ruthenium, platinum, palladium, nickel, and alloys thereof. It can be made from tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), or In--Ga--Zn composite oxide (IGZO). The materials constituting the target material 2 are not limited to these. For example, the material for the target material 2 for electrodes and wiring materials is preferably Al or an Al alloy, such as Al with a purity of 99.99% or more, more preferably 99.999% or more, or Al using these as a base material. Particular preference is given to using alloys (Al--Cu, Al--Si, Al--Cu--Si). High-purity Al has a relatively large coefficient of linear thermal expansion, so it is easily warped by the heat it receives during sputtering and easily peels off from the backing plate. However, the present invention improves the bonding rate and reduces the maximum defect area. This prevents it from peeling off from the backing plate.

The backing plate 3 is formed into 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 in the lateral direction of the backing plate 3 is defined as a first direction D1, and the other direction in the lateral direction of the backing plate 3, which is opposite to the first direction D1, is defined as a second direction D2.

The backing plate 3 has a bonding area 30 (indicated by hatching) on the upper main surface 3a. The bonding area 30 is an area where the target material 2 is to be bonded. The shape of the bonding 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 the long sides when viewed from the top surface. 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 are formed facing each other in the lateral direction of the backing plate 3. 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, such as metal or an alloy thereof. Examples of the metal include copper, copper alloy, aluminum, aluminum alloy, titanium, SUS, and the like.

The joint surface of the target material 2 and the joint region 30 of the backing plate 3 are preferably flat, and from the viewpoint of easily reducing slippage when sliding or reversing the target material 2 and the maximum defect area, the flatness is preferably 1. .0 mm or less, preferably 0.5 mm or less, more preferably 0.3 mm or less. Flatness is a numerical value indicating the smoothness (uniformity) of a plane, and refers to the amount of deviation of a plane from a geometrically correct plane. Further, from the viewpoint of preventing the bonding material from flowing on the bonding area 30 of the backing plate 3 during bonding, the backing plate 3 may have an upper main surface 3a and its back surface substantially parallel, preferably parallel. In order to make it easier to apply a constant force to the target material 2 when sliding or reversing the target material 2, the sputtering surface 2a on the upper surface of the target material 2 and the bonding surface on the back thereof may be approximately parallel, preferably parallel. .

The bonding process is performed with the target material 2, backing plate 3, and bonding material 4 heated. As shown in FIG. 1B, the bonding material 4 is applied to the entire surface of the 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, more preferably 4.5×10 ⁻⁶ kg/mm 2 or more. ² or more, more preferably 10×10 ⁻⁶ kg/mm ² or more, even more preferably 14×10 ⁻⁶ kg/mm ² or more. The upper limit is not particularly limited, but from the viewpoint of workability in the joining process, it is preferably 50×10 ⁻⁶ kg/mm ² or less, more preferably 35×10 ⁻⁶ kg/mm ² or less, and even more preferably 25×10 ^-6 kg/ ^mm2 or less. The bonding material 4 is made of a metal with a low melting point (for example, 723K or less) such as solder or brazing filler metal, and the solder material is, for example, indium, tin, zinc, lead, silver, copper, bismuth, cadmium, antimony, etc. or alloys thereof, such as 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, Generally, it is preferable to use a solder material such as In, In alloy, Sn, or Sn alloy, which has a low melting point. The bonding is performed at a temperature higher than the melting point of the bonding material 4, preferably 140°C or higher, more preferably 150°C or higher and 300°C or lower, and the viscosity of the molten bonding material 4 is 0.5 mPa·s or higher. , preferably 1.0 mPa·s or more, more preferably 1.5 mPa·s or more, and 5 mPa·s or less, preferably 3 mPa·s or less, more preferably 2.5 mPa·s or less, the bonding rate can be reduced. The maximum defect area can also be reduced. Furthermore, before bonding the target material 2 and the backing plate 3, the bonding surface of the target material 2 with the backing plate 3 and the bonding surface of the backing plate 3 with the target material 2 are tested for wettability with the bonding material 4. Pretreatment (metallization treatment) can be performed to improve the quality. Regarding pretreatment, rough surface processing, hairline processing, grain processing, and metallization processing can be performed by polishing or grinding, and polishing, grinding, hairline processing, etc. can be performed on the joint 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 an abrasive material in which abrasive grains are applied to a paper or fiber base material, or by using a polishing machine equipped with an abrasive material. The metallization process can be performed by applying a metallization material to the bonding surface and irradiating it with ultrasonic waves. The metallizing material can be selected from the same materials as the bonding material 4, and for example, In material and Sn--Zn material can be used. The thickness of the metallized layer is 1 μm or more and 100 μm or less, and within this range, it is easy to ensure wettability with the bonding material 4 and improve the bonding rate. Note that the portions where the target material 2 and the backing plate 3 are not bonded may be masked in advance with a heat-resistant tape to prevent adhesion of the bonding material 4 and formation of a metallized layer.

As shown in FIG. 1C, the first edge 21 of the target material 2 is then 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 is then moved from the first edge 31 side 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 target material.

As shown in FIG. 1E, the target material 2 is then slid and moved in the second direction D2 along the main surface 3a of the backing plate 3 to align the target material 2 with the bonding region 30 of the backing plate 3. After that, the target material 2 and the backing plate 3 are precisely aligned, and the joined body of the target material 2 and the backing plate 3 is cooled while the two are fixed by placing a weight or holding them in a vise, vice, or clamp. Then, the bonding material 4 is solidified. Thereby, the target material 2 and the backing plate 3 are bonded by the bonding material 4, and the sputtering target 1 is manufactured.

According to the joining method, the target material 2 is made to match the joining area 30 of the backing plate 3 by sliding the target material 2 in the first direction D1 with respect to the backing plate 3 and then reversing it in the second direction D2. ing. In this way, by not only sliding but also reversing the target material 2, the bonding material 4 can be pulled back in the second direction D2 by surface tension as the target material 2 reverses, and the bonding material 4 between the target material 2 and the backing plate 3 can be pulled back in the second direction D2 by surface tension. The space where the bonding material 4 does not exist can be reduced, and the unbonded area can be made smaller.

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 the ratio of the bonding area of the bonding location between the target material 2 and the backing plate 3 to the area of the bonding region 30.
Specifically, the bonding area refers to the total area of the area where no bonding material is present, as 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 a location that is located between the target material 2 and the backing plate 3 and has the largest area among the locations where the bonding material 4 is not present. Here, the area where the bonding material 4 is not present (unbonded area) is a region where the bonding material is not present in the thickness direction of the bonding layer, that is, a space or a foreign matter other than the bonding material such as an oxide of the bonding material. This refers to the location where the bonding material is detected, and may include not only the entire thickness of the bonding layer but also a portion where there is no bonding material. 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 is not present in a part of the bonding layer 6 in the thickness direction (vertical direction in the figure). Alternatively, as shown in FIG. 2B, a space S may exist in the bonding layer 6 between the target material 2 and the backing plate 3 in the thickness direction of the bonding layer 6 (vertical direction in the figure). There may be a space S in which the bonding material 4 is not present throughout. The area where the bonding material does not exist can be detected using the measurement method described below. For example, when using ultrasonic flaw detection and measurement, if there is a space in the bonding layer where no bonding material is present, the incident ultrasonic waves will be reflected at the interface, making it possible to recognize the defective portion.

Therefore, according to the present invention, it is possible to increase the bonding rate between the target material 2 and the backing plate 3 and to reduce the maximum defect area, so that a portion with low bonding strength is less likely to be formed and the target material 2 is not peeled off. It is possible to manufacture a sputtering target 1 that is difficult to use.

Thus, in the present invention, it has been found that by paying attention to both the bonding rate and the maximum defect area, the target material 2 becomes difficult to peel off during sputtering. Specifically, regarding the bonding rate, when the bonding rate increases, the area where the bonding material 4 is not present can be reduced, and the target material 2 becomes difficult to peel off.

On the other hand, regarding the maximum defect area, if the maximum defect area increases, large defects will occur locally, which will deteriorate electrical and thermal conductivity in that area, causing heat concentration to occur in that area, and As the material 4 melts, the target material 2 becomes easy to peel off. Therefore, when the maximum defect area becomes smaller, large defects do not occur locally, and the target material 2 becomes difficult to peel off.

Further, according to the joining method, the target material 2 is slid and moved with respect to the backing plate 3 in the lateral direction of the backing plate 3. According to this, in the elongated target material 2 and 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 perpendicular to the first direction D1. Then, in moving the target material 2 in the first direction D1 and the second direction D2, the target material 2 is moved by sliding on the wire 5. According to this, since the target material 2 is slid 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, more preferably 0.1 mm or more and 0.3 mm or less. According to this, the wire 5 is less likely to break, and variations 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 The bonding material 4 is replenished on the edge 31 side. Specifically, in the state shown in FIG. 1D, the bonding material 4 is added to the portion of the bonding region 30 that is not covered with the target material 2. According to this, since the bonding material 4 is replenished on the first edge 31 side of the bonding region 30 of the backing plate 3, the bonding material 4 is replenished at the first edge 31 side of the bonding region 30 where the bonding material 4 is likely to be insufficient as the target material 2 moves. The bonding material 4 can be replenished on the edge 31 side, the bonding rate can be further improved, and the maximum defect area can be further reduced. The amount of the bonding 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 even more preferably 1.0×10 ⁻⁶ kg/ ^mm2 or more. The upper limit is not particularly limited, but from the viewpoint of workability in the joining process, it is preferably 20×10 ⁻⁶ kg/mm ² or less, more preferably 10×10 ⁻⁶ kg/mm ² or less, and even more preferably 7.0 ×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. , the distance in the first direction D1 from the second edge 32 of the bonding area 30 of the backing plate 3 to the first edge 21 of the target material 2 is defined as A, and the width of the bonding area 30 in the first direction D1 is where W is 0.03≦A/W<1.0, preferably 0.05≦A/W≦0.8, 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 moving distance of the target material 2 relative to the backing plate 3 can be reduced, the bonding rate can be improved, and the maximum defect area can be reduced.

Preferably, in the step of moving the target material 2 in the first direction D1, the first edge 21 of the target material 2 is arranged on the first edge 31 side of the bonding region 30 of the backing plate 3, as shown in FIG. At this time, 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, even more preferably 0.10≦B/W ≦1.0. Specifically, 0 mm≦B≦300 mm, preferably 5 mm≦B/W≦200 mm, and preferably 150 mm≦W≦300 mm. According to this, the moving distance of the target material 2 relative to the backing plate 3 can be reduced, the bonding rate can be improved, and the maximum defect area can be reduced.

The speed of movement (slide) of the target material 2 in the first direction D1 and movement (reverse) of the second direction D2 is 100 mm/sec or less in order to prevent excess movement and escape of the bonding material placed in the bonding area. The speed is preferably 50 mm/sec or less, and even more preferably 30 mm/sec or less. The lower limit is not particularly limited, but from the viewpoint of productivity, it is 1 mm/sec or more, preferably 5 mm/sec or more.

At the stage where the edge of the target material 2 is arranged on the first edge side of the joining area of the backing plate, and/or at the stage when the movement (sliding) of the target material 2 in the first direction D1 is completed, the target material 2 It is preferable to provide a step of applying vibration from the upper surface of the bonding layer to remove air that may exist in the bonding layer. As means for applying vibration, a method of lightly tapping the upper surface of the target material or a method of applying vibration in a direction parallel to the upper surface of the target material 2 can be performed. At the stage where the edge of the target material 2 is placed on the first edge side of the bonding area of the backing plate, the range to which vibration is applied is the entire bonding layer between the target material and the backing plate (the area on which the target material rides). It is preferable to perform the bonding area) at the beginning of the movement (reverse) movement in the second direction D2 at the stage when the movement (slide) of the target material 2 in the first direction D1 is completed. The direction in which vibration is applied is preferably from the center of the bonding layer between the target material and the backing plate (the bonding region on which the target material is placed) toward the outer periphery. As a result, air present in the bonding layer can be removed, so that the bonding rate can be improved and the maximum defect area can be reduced. In particular, when the edge of the target material 2 is placed on the first edge side of the bonding area of the backing plate, the bonding layer between the target material and the backing plate (the bonding area on which the target material is placed) Since there is a high possibility that air pockets exist, by providing an air removal step, it is possible to further improve the bonding rate and reduce the maximum defect area.

Next, a method for manufacturing the sputtering target 1 will be explained. As described above, a sputtering target is manufactured 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 of processing the target material into a plate shape is not particularly limited. Target materials made from metal materials are, for example, rectangular, cylindrical, or cylindrical target materials obtained by melting or casting, subjected to plastic processing such as rolling, extrusion, or forging, and then cutting or grinding. By performing mechanical processing such as , polishing (cutting, milling, end milling, etc.), a target material with a desired size and surface condition can be manufactured. The rolling process is described in, for example, Japanese Patent Application Publication No. 2010-132942 and International Publication No. 2011/034127. Extrusion processing is described, for example, in JP-A-2008-156694. Forging processing is described, for example, in JP-A No. 2017-150015, JP-A No. 2001-240949, or the Aluminum Technology Handbook (edited by the Light Metals Association Aluminum Technology Handbook Editorial Committee, Karos Publishing, new edition, published November 18, 1996). It is described in A sputtering target is manufactured by bonding a machined plate-shaped target material to a backing plate using the bonding method of the present invention. In addition, the target material may be a purchased target material machined to a predetermined size, or an abnormality may occur in the bonding with the backing plate during the manufacturing process of the sputtering target 1, resulting in deviation from the product specifications. The target material may be obtained by removing the backing plate from the sputtering target and removing the bonding material. Note that, if necessary, the surface of the sputtering target after bonding may be finished by cutting or polishing.

Since the sputtering target manufacturing method of the present invention uses the bonding method of the present invention, a sputtering target with improved quality can be obtained.

Next, the sputtering target 1 bonded by the above bonding method will be described.

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

FIG. 3A is a simplified diagram showing the state of the bonding material 4 between the target material 2 of the sputtering target 1 and the backing plate 3. In FIG. 3A, defective locations (unbonded locations) 10 where no bonding material 4 is present in the bonding region 30 are indicated by hatching. The defect location 10 can be measured using, for example, ultrasonic flaw detection measurement or transmission type 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 device, FS LINE and FS LINE Hybrid manufactured by Hitachi Power Solutions Co., Ltd., phased array ultrasonic flaw detection visualization device PDS and ultrasonic flaw detection visualization device ADS71000 manufactured by KJTD Co., Ltd., etc. can be used. In addition, when determining the bonding rate and maximum defect area by ultrasonic flaw detection measurement, a pseudo defect sample with a flat bottom hole of a predetermined size is used, and ultrasonic flaw detection measurement conditions are set to recognize the reflected waves from the defective part. Adjustments will be required. Since the propagation speed of ultrasonic waves differs depending on the material, it is preferable that the pseudo-defect sample be made of the same material as the material on the ultrasonic incidence side of the sputtering target 1 in order to align measurement sensitivity and conditions. Further, it is preferable that the distance between the ultrasonic incidence surface of the pseudo-defect sample and the bottom surface of the flat-bottomed hole is equal to the distance between the ultrasonic incidence surface of the sputtering target 1 and the bonding layer.

As shown in FIG. 3A, the area of the portion between the target material 2 and the backing plate 3 where the defective location 10 is not detected is 97% or more of the area of the bonding region 30. That is, the bonding rate is 97% or more, preferably 98% or more, and more preferably 98.5% or more. Further, the maximum defect area of the defect spot 10 in the bonding layer between the target material 2 and the backing plate 3 is 2% or less, preferably 1% or less, and more preferably 0% with respect to the area of the bonding region 30. .6% or less, more preferably 0.3% or less, even 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 x 2300 mm, the maximum defect area is 2000 mm ² or less.

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

The upper limit of the bonding rate is 100%, but from the viewpoint that the target material is easy to peel off when removing the backing plate from a sputtering target that is out of specification due to an abnormality during bonding, or a sputtering target that has been used for sputtering. Therefore, the bonding rate is preferably 99.99% or less, more preferably 99.95% or less, and still more preferably 99.90% or less. In addition, by applying heat to the sputtering target to a temperature higher than the melting point of the bonding material used for bonding, the bonding layer is softened or melted, and if necessary, the bonding layer is physically destroyed. The target material can be peeled off.
The lower limit of the ratio of the maximum defect area to the area of the bonding region 30 is not particularly limited, but from the viewpoint of further suppressing warpage of the sputtering target due to heat generated during sputtering, it is 0.001% or more, preferably 0.003%. The content is more preferably 0.005% or more, still more preferably 0.008% or more. When the lower limit of the maximum defect area ratio is equal to or higher than the above, deformation of the target material caused by heat during sputtering is alleviated by the local defects, and warpage of the sputtering target is reduced.

On the other hand, FIG. 3B shows a sputtering target 100 of a 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 sputtering target 100 is a comparative example in which the target material and the backing plate are bonded together by simply sliding the target material in the first direction D1. Indicates the condition of the bonding material. As shown in FIG. 3B, compared to FIG. 3A, the proportion of defective locations 10 is higher, the bonding rate is lower, and the maximum defect area of the defective locations 10 is larger. In this way, only by sliding the target material, the bonding state between the target material and the backing plate deteriorates, and as a result, the target material becomes easy to peel off. In particular, if the target material is long or the sputtering target has a large bonding area, the target material is likely to peel off easily.

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 a wire in the bonding layer, it is easy to ensure the thickness of the bonding layer, and it is also easier to make the thickness of the bonding layer more constant, so the bonding rate of the sputtering target 1 can be increased and the maximum defect area can be reduced, and the target material It is possible to manufacture a sputtering target 1 in which the sputtering target 2 is difficult to peel off.

(Example 1)
A rolled plate made of high-purity Al with a purity of 99.999% is prepared, and a target material of 200 mm x 2300 mm x T16 mm is prepared by cutting with a portal machining center (the area of the bonding area is 4.5 x 10 ⁵ mm ² ). A backing plate made of oxygen-free copper with a purity of 99.99% was prepared. The width W of the bonding area in the first direction D1 (so-called width of the target material) in the target material movement process 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 joint surface of the target material, and the In material was melted on the joint surface of the backing plate, and metallization treatment was performed on the joint surfaces of both materials using an ultrasonic soldering iron. After the metallization process, the oxides of the Sn-Zn-In alloy material and In material on the joint surface of the target material and the joint surface of the backing plate and the excess Sn-Zn-In alloy material and In material were removed with a spatula. .

Ten SUS wires with a diameter of 0.2 mm are arranged at approximately equal intervals in a direction perpendicular to the longitudinal direction of the backing plate on the bonding surface of the metallized backing plate, and an In material for bonding is placed over the SUS wires. was applied on the joint surface. The amount of In material for bonding applied onto the bonding surface from above the above-mentioned SUS wire was 7.80 kg.

Change the direction of the target material so that the joint surface of the target material faces parallel to the joint surface of the backing plate, and place it on the wire so that one long side of the target material overlaps one long side of the backing plate. (target material installation position B=0), and the target material was slid in the direction of a predetermined bonding position. The target material is moved in the second direction D2 ( The head of the machine (reverse) was lightly tapped from above to knock out the air.

Thereafter, the target material was slid to a predetermined joining position. The target material position was finely adjusted 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, warpage caused by the difference in linear expansion coefficient between the target material and the backing plate was corrected to obtain a target. The bonding rate and maximum defect area were measured using an ultrasonic flaw detector FS-LINE manufactured by Hitachi Power Solutions Co., Ltd.

The bonding rate and maximum defect area were measured using the following procedure. First, a rolled plate made of high-purity Al with a purity of 99.999% is used, and after chamfering both sides of the rolled plate to make parallel surfaces, a flat bottom hole with a circular equivalent diameter (diameter) φ of 2 mm is opened from one side. , a pseudo-defect sample with a counterbore hole of φ6 mm was prepared. At this time, the distance from the sample surface with no holes to the flat-bottomed hole was made to be the same as the thickness of the target material.

In preparation for the measurement, an ultrasonic flaw detector "I3-1006-T S-80mm" (frequency 10MHz, focal length 80mm) was attached to the measurement device.

Then, the pseudo-defect sample was placed in the measuring device, the countersunk hole was focused, and the measurement was started. First, I checked the counterbore hole, and then, while focusing on the counterbore hole, I checked the flat bottom hole. He then focused on the flat-bottomed hole. In this state, ultrasonic flaw detection (C-scan) was performed, and the sensitivity was adjusted so that the diameter of the detected flat-bottomed hole matched the diameter of the flat-bottomed hole of the pseudo-defect sample.As a result, the measurement conditions were as follows: ) was set to 12 dB, the measurement pitch was set to 2 mm pitch, and the defect level was set to 38. As a result, the sensitivity of the program was adjusted so that a reflected echo with an intensity 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 placed in the measuring device with the target material side facing upward. Set the height of the ultrasonic flaw detector so that the focal point height 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 flaw detector so that the measurement field of view covers the entire bonding surface. , Ultrasonic flaw detection measurement (C scan) was performed on the bonded sputtering target. The ultrasonic waves were incident from the target material side.

The obtained data was analyzed using the analysis program attached to the ultrasonic flaw detection device, and information on bonding rate and maximum defect area was obtained. Thereafter, the surface was finished by polishing and blasting.

Table 1 shows the results of the sputtering target bonded as in Example 1.

(Examples 2 to 12)
With the amount of bonding material, wire diameter, bonding grade, target material installation position B, and overrun amount A shown in Table 1, after installing the target material 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 air in the bonding layer was removed by lightly tapping almost the entire surface of the bonding area (contact area, bonding area on which the target material is placed) from above. In Examples 2 to 12, the target material was slid in the first direction and then reversed in the second direction in the same manner as in Example 1.
(Example 13)
In Example 13, the bonding surface of the backing plate was metallized with Sn-Zn material, Sn-Zn (containing 9% Zn) was used as the bonding material, and the air in the bonding layer was not punched out. A sputtering target was produced in the same manner as in Example 2, and the bonding rate and maximum defect area were determined.
(Comparative example 1)
Comparative Example 1 was carried out in the same manner as Examples 2 to 12 except that the target material was only slid in the first direction and not reversed in the second direction.
(Comparative example 2)
In Comparative Example 2, a sputtering target was produced under the conditions listed in Table 1 without sliding or reversing the target material or blowing out air, and without sliding or reversing the target material.

In Table 1, the "installed bonding material amount" refers to the amount of bonding material applied to the bonding area 30 of the backing plate 3 in FIG. 1B. The "replenishment amount of bonding material" refers to the amount of bonding material replenished to the bonding region 30 of the backing plate 3 through which the target material has passed in FIG. 1D. "Wire type" refers to the type of wire 5 installed in the bonding area 30 of the backing plate 3 in FIG. 1A, and stainless steel is used. “Wire diameter” refers to the diameter of the wire 5. The term "bonding material type" refers to the material of the bonding material, and solder made of In or Sn--Zn is used. “Target material installation position” refers to the position where the target material 2 is installed in FIG. This is the distance B in the direction D1. "Air blowing" refers to the stage in which the edge of the target material 2 is placed on the first edge side of the joining area of the backing plate in FIG. 1C, and the movement of the target material 2 in the first direction D1 in FIG. 1D ( When the slide) is finished, the upper surface of the target material 2 is struck to remove the air between the target material 2 and the backing plate 3. "Target material overrun amount" refers to the amount by which the target material 2 protrudes from the bonding area 30, and in FIG. 1D, from the second edge 32 of the bonding area 30 of the backing plate 3 to the first edge of the target material 2. 21 in the first direction D1. "Replenishment of bonding material" refers to whether or not to replenish bonding material.

As can be seen from Table 1, in Examples 1 to 13, the bonding rate 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. 6% or less). In Examples 1 to 13, the target material was difficult to peel off, and no peeling of the target material was observed even after use in a sputtering device.

On the other hand, in Comparative Example 1, the bonding rate was 90.70% and the maximum defect area was 11628 ^mm2 , and in Comparative Example 2, the bonding rate was 96.27% and the maximum defect area was 11628 mm2. The area is ^1948mm2 . In Comparative Examples 1 and 2, the target material was easily peeled off.

Note that the present invention is not limited to the above-described embodiments, and design changes can be made without departing from the gist of the present invention.

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

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

Claims (2)

backing plate and
and a target material bonded to the bonding region of the backing plate via a bonding material,
The joint area of the joint between the target material and the backing plate is 97% or more of the area of the joint region,
A sputtering target, wherein a maximum defect area of a portion where no bonding material exists between the target material and the backing plate is 0.6% or less with respect to the area of the bonding region. The sputtering target according to claim 1, wherein the length of the target material is 1000 mm or more and 4000 mm or less.

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