KR20160108226A - Target - Google Patents

Abstract

Provided is new type of target having an efficiency of high utilization and low manufacturing costs by expanding an erosion area due to a sputter, even if a strip type target material is used. The target is a target in which a strip type target material of which a surface of a sputter and a rear surface of the surface of the sputter having a plane shape and a backing plate of which a surface bonding with the target material has a plane shape are bonded with a bonding material. In both end parts of the target material in a longitudinal direction, a plane shaped shunt is arranged along an outer circumferential portion of both end parts of the target material between the target material and the backing plate; and the shunt is bonded with the target material and the backing plate by a bonding material.

Description

Target {TARGET}

The present invention relates to a target used in a magnetron sputtering method.

For example, in a sputtering method known as a thin film forming technique used for a wiring film of an electronic component or the like, a target material which is a base material of a thin film in a vacuum chamber and a substrate or the like are disposed at a position opposing the target material, . Specifically, a rare gas is introduced into a vacuum chamber, DC or AC power is applied to the target material to generate glow discharge on the surface of the target material, atoms of the target material are struck with rare gas ions, And is widely used industrially.

Among these sputtering methods, the magnetron sputtering method is a method in which a magnet unit is disposed on the back surface of a target material, a tunnel magnetic force line is generated on the surface of the target material, and electrons generated in the glow discharge are captured on the target surface to increase the electron density. This magnetron sputtering method is widely used because it can generate a stable glow discharge with a low rare gas pressure and can realize an excellent thin film quality at a high film forming speed.

As the shape of the target material used in the sputtering method described above, there are a planar disk, a planar rectangle, a cylinder and the like. Among them, a strip-shaped target material having a flat sputter surface is widely used in a flat panel display manufacturing apparatus represented by a liquid crystal display (See, for example, Non-Patent Document 1).

The magnet unit used in the magnetron sputtering apparatus using this strip-shaped target material is characterized in that a magnet (central magnet) is disposed along the longitudinal direction at the center of a rectangular yoke which is typically arranged in parallel with the target material, And a magnet (outer magnet) is disposed around the entire outer periphery in a surrounding form. This magnet unit can generate a line of magnetic force for drawing an elliptical tunnel-like arch when the surface of the target material is viewed from above by setting the central magnet to the N pole and the outer magnet to the S pole (see, for example, Patent Document 1 ).

In this magnet unit, since the magnetic force line horizontal region on the surface of the target material becomes narrow in the vicinity of both end portions in the longitudinal direction of the target material, the erosion of the target material (hereinafter also referred to as erosion) locally narrows, It is known that the utilization efficiency of the target material is lowered. This problem leads to an increase in manufacturing cost in the manufacture of a flat panel display in which a thin film is formed using a target material made of an expensive rare metal such as Mo, for example.

In order to solve the problem that the utilization efficiency of the target material is lowered, a structure has been proposed in which only the vicinity of both end portions in the longitudinal direction of the target material is made thicker in consideration of the shape of the target material.

On the other hand, a structure has been proposed in which a magnetic shunt having a triangular outline is fixed on a predetermined region in the longitudinal direction of the strip-shaped target material, focusing on the magnetic flux at the time of forming the thin film, in order to solve the problem that the utilization efficiency of the same target material is lowered . This structure is excellent in that the magnetic field generated on the surface of the target material is locally weakened to change the shape of the plasma to expand the erosion region of the target material and to improve the utilization efficiency of the target material See Patent Document 2).

Japanese Patent Application Laid-Open No. 7-34244 (page 5, Fig. 1) Japanese Patent Application Laid-Open Publication No. 2012-201910 (page 10, Fig. 3)

"Development and Tasks of Large Sputtering Device for Flat Panel Display (FPD) Manufacturing", J. Vac.Soc.Jpn. (Vacuum), P.28-31

In the method of partially thickening only the vicinity of both end portions in the longitudinal direction of the target material described above, it is necessary to prepare a dedicated mold or HIP can to form a step, as compared with a target material of a simple plate, There is a case. Further, in the case of forming a step from a target material of a flat plate, which is a simple shape, it is necessary to cut the target material, and the number of machining steps becomes long, and a large amount of machined chips are generated and the yield is reduced. As a result, the manufacturing cost of the target material increases.

Further, in the method of fixing the magnetic shunt having the outline of the triangle in the longitudinal direction of the strip-shaped target material, a large-scale addition of the target material may be required when the target material is loaded in the conventional sputtering apparatus. In addition, the intensity and distribution of the magnetic flux generated from the magnet unit during sputtering become uneven, and the erosion area by the sputter may become uneven.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel target having a high utilization efficiency and a low manufacturing cost by enlarging an erosion area by a sputter even if a strip target material is used to solve the above problems.

The present inventors have studied a method for improving the utilization efficiency by suppressing non-uniform erosion of the target material by making the strength and distribution of the magnetic flux generated from the magnet unit for the strip-shaped target member uniform.

As a result, it has been found that the utilization efficiency of the target material is greatly improved by making the joining surface of the target material and the backing plate flat and inserting a shunt having a specific shape at a specific position of the joining surface.

That is, the present invention is a target having a sputter surface and a strip-shaped target material having a flat shape on the back surface of the sputter surface, and a backing plate having a flat surface to be bonded to the target material, A plate-shaped shunt is disposed between the target material and the backing plate at both longitudinal ends thereof along the outer circumferential portion of both ends in the longitudinal direction of the target material, and the target material and the backing plate are bonded to each other via the bonding material It is the invention of the target.

The shunt applied in the present invention is preferably substantially U-shaped.

It is further preferable that the shunt has a substantially U-shaped inner peripheral portion formed of a ferromagnetic material and an outer peripheral portion formed of a non-magnetic material.

The target of the present invention preferably includes a supporting member for supporting the target material between the target material and the backing plate.

It is preferable that the support member is made of a wire.

Since the target of the present invention employs a strip-shaped target material, the manufacturing cost is low and the erosion area of the target material can be enlarged, so that a high utilization efficiency can be obtained, which is a technique useful for forming a thin film.

1 is a schematic diagram showing an example of a target of the present invention.
2 is a schematic diagram showing an example of a shunt shape applied in a target of the present invention.

As described above, an important feature of the present invention is that a joining surface of the target material and the backing plate is made flat, a shunt is inserted at a specific position of the joining surface, and the joining is performed through the bonding material. Specifically, as shown in Fig. 1, the target of the present invention includes a target material 1 having a sputter surface and a flat shape on the back surface thereof, and a surface having a flat surface to be bonded to the target material 1 The backing plate 2 is a target bonded through the bonding material 3. A plate-shaped shunt 4 is disposed between the target material 1 and the backing plate 2 at both ends in the longitudinal direction of the target material 1 along the outer periphery of both ends in the longitudinal direction of the target material 1 The target material 1 and the backing plate 2 are bonded to each other through the bonding material 3 and the shunt 4 in the cross section in the longitudinal direction. Hereinafter, the target of the present invention will be described in detail.

In the target of the present invention, the sputter surface of the target material and the back surface of the sputter surface are formed into a flat shape without any unevenness or step. Thus, the target material used in the present invention does not require complicated molds or HIP cans, simplifying the processing of the target material 1, and minimizing the cutting chips generated by the machining. Therefore, Can be suppressed.

Further, since the backing plate used in the present invention also has a flat shape like the sputter surface and the rear surface of the target material, it is possible to suppress the manufacturing cost without requiring special machining as in the case of the target material.

In the present invention, a plate-shaped shunt 4 is disposed between the target material 1 and the backing plate 2 at both longitudinal ends of the target material 1 along the outer periphery of both longitudinal ends of the target material 1 . Thus, the target of the present invention exerts the following two effects.

In the magnet unit used for the strip-shaped target material, magnetic lines of force at both ends in the longitudinal direction draw a substantially U-shaped tunnel-shaped arch. In this region, the horizontal magnetic field lines are particularly narrow, and the strength of the magnetic field varies depending on the location. Therefore, the erosion of the target material locally narrows and proceeds deeply. Therefore, in the present invention, the use efficiency of the target material can be improved by disposing a shunt at a portion along the outer peripheral portion of both ends in the longitudinal direction of the target material in which erosion proceeds, and controlling the magnetic line of force.

In addition, the target of the present invention can effectively control the magnetic line of force in the vicinity of the surface of the target material 1, by placing the shunt 4 between the target material 1 and the backing plate 2.

The shunt to be used in the present invention may be a ferromagnetic material. Examples of the shunt include pure metals such as Fe, Ni, and Co. Examples of the shunt include alloys such as permalloy and SUS430. Can be appropriately selected according to the required magnetic properties. Since the shunt applied in the present invention is disposed along the outer periphery of both end portions in the longitudinal direction of the target material, the shunt has a shape along the outer periphery of both ends in the longitudinal direction of the target material as shown in Fig.

The size and thickness of the shunt applied in the present invention may be set according to the distribution of magnetic force lines generated from the magnet unit and the strength of the magnetic field. The thickness may be partially changed, or a material having a different magnetic property may be bonded.

In the present invention, it is preferable that the shape of the shunt 4 is substantially U-shaped as shown in Fig. 2 (b), and the U-shape is arranged according to the U-shape of both ends in the longitudinal direction of the target material . Magnetic lines of force generated at both ends in the direction of the long side of the magnet unit of the sputtering apparatus are in a tunnel shape that draws a substantially U shape when the target is viewed from above. By inserting a substantially U-shaped shunt matching the tunnel shape, It is possible to further improve the utilization efficiency of the target material by reducing the fluctuation of the intensity of the local magnetic field. When the shunt 4 is formed in a substantially U-shape, a non-magnetic body may be inserted into the inner peripheral portion of the ferromagnetic body, as shown in Fig. 2 (c) It is possible to secure a function of supporting the light source.

In the present invention, as shown in Fig. 2 (d), it is preferable that the substantially U-shaped inner peripheral portion of the shunt 4 is made of a ferromagnetic material and the outer peripheral portion is made of a non-magnetic material. When bonding the target material 1 and the backing plate 2 via the bonding material 3, it is necessary to accurately arrange the U-shaped shunt 4 at a predetermined position on both ends in the longitudinal direction. At this time, it is preferable that the outer contour of the substantially U-shaped shunt 4 has the same shape as that of the outer periphery of the target material 1 in order to facilitate positioning. The inner peripheral portion of the substantially U-shaped shunt 4 is made of a substantially U-shaped ferromagnetic body having a shunt function and the outer peripheral portion of the substantially U-shaped shunt 4 is made of a non-magnetic body, Shunt 4 is preferable. Thus, positioning at the time of bonding can be performed accurately and quickly.

The outer circumferential portion of the shunt 4 has a contour corresponding to the shape of the outer circumferential portion of the target material, and may have a function of supporting an inner circumferential portion made of a substantially U-shaped ferromagnetic material. This is because if the outer peripheral portion of the shunt 4 has ferromagneticity, the function of the shunt 4 may be impaired depending on the sputter conditions. 2 (e), when the shunt 4 is formed in a substantially U-shape, a non-magnetic body may be inserted into the inner peripheral portion of the ferromagnetic body, thereby supporting the inner peripheral portion of the shunt It is possible to secure a function of

The nonmagnetic material used for the outer peripheral portion of the shunt 4 may be appropriately selected from, for example, Cu, Al or an alloy containing them in an amount of 50 mass% or more, which has a high thermal conductivity, have.

In the present invention, it is preferable to dispose the support member 5 exemplified in Fig. 1 between the target material 1 and the backing plate 2. Fig. Thus, the target of the present invention can keep the distance between the target material 1 and the backing plate 2 constant. The support member 5 used in the present invention preferably has a thickness that can ensure the same height as the thickness of the shunt 4 so that the spacing between the target material 1 and the backing plate 2 is constant The thickness of the bonding material 3 can be made uniform, and stable bonding can be achieved.

When the shunt 4 is arranged at both end portions of the backing plate 2, the support member 5 is previously arranged so that the end portion of the shunt 4 comes to a position where it should be placed The positioning of the shunt 4 can be performed accurately and quickly. This is a particularly effective means because the joining surfaces of the target material and the backing plate used in the present invention are flat and free from irregularities or steps over the entire length in the longitudinal direction.

In the present invention, it is preferable to use a wire as the support member 5. At this time, the volume of the wire to be the support member 5 is reduced, and the support member 5 is brought into line contact with the target material 1 and the backing plate 2 so that the target material 1 and the backing plate 2 ) Of the supporting member 5 at the position where the bonding material 3 is disposed. Thus, the target of the present invention can arrange the bonding material 3 in a uniform thickness while keeping the gap between the target material 1 and the backing plate 2 constant, and can secure the bonding strength and maintain the heat conduction Lt; / RTI > As the material of the support member 5, any material can be used as long as it has a high thermal conductivity, is easily processed such as cutting, and has appropriate rigidity.

1, the support member 5 can be disposed parallel to the longitudinal direction of the target material 1 at predetermined intervals in the longitudinal direction, and can extend in the longitudinal direction of the target material 1 at predetermined intervals As shown in Fig.

[Example]

First, a Mo target material having a sputter surface and a back surface of the sputter surface and having a shape of 16 mm thick x 180 mm wide x 2650 mm long and having a purity of 99.95% and a planar surface having a flat surface bonded to the back surface of the target material And a shunt having a thickness of 0.3 mm in which Ni was placed in the ferromagnetic body portion and Cu was arranged in the non-magnetic body portion, as shown in Fig. 2 (d).

1, the shunt 4 is sandwiched between the target material 1 and the backing plate 2 at both ends in the longitudinal direction of the target material 1 so that the length of the target material 1 And the target material 1 and the backing plate 2 were bonded to each other through the bonding material 3 and the shunt 4 to produce the target of the present invention.

In addition, a target, which is a comparative example in which the target material and the backing plate were joined together only through the bonding material without inserting a shunt, was also produced.

Each of the targets obtained above was placed in a magnetron sputtering apparatus of ULVAC Co., Ltd., and sputtering tests were performed under conditions of using an AC power source, using Ar gas as a sputtering gas, a gas pressure of 0.8 Pa, and an input power of 80 kW . During the course of the sputtering, the sputtering was stopped several times, and the integrated power = power [kW] x sputter time [hr] until the remaining thickness of the target material at the deepest part of the erosion was 1 mm or less was measured. The results are shown in Table 1.

When the sputtering test was performed using the target, which is a comparative example in which the target material and the backing plate were bonded only through the bonding material, the accumulated electric power until the remaining thickness of the target material became 1 mm or less as the erosion progressed was 15000 kWh .

On the other hand, when the sputtering test is performed using the target of the present invention in which the shunt of a specific shape is inserted at a specific position, the cumulative electric power until the remaining thickness of the target material becomes 1 mm or less as the erosion progresses is 19000 kWhr Which was significantly increased for the comparative example. This means that the lifetime of the target has been greatly improved, and the effectiveness of the target of the present invention can be confirmed.

1: target material
2: Backing plate
3: Bonding material
4: Shunt
5: Support member

Claims (5)

A strip shaped target material having a sputter surface and a back surface of the sputter surface in a flat shape and a backing plate having a flat surface to be bonded to the target material are bonded to each other via a bonding material, Wherein a plate-shaped shunt is disposed between the target material and the backing plate along the outer periphery of both ends in the longitudinal direction of the target material, and the target material and the backing plate are bonded to each other via the bonding material. target. 2. The target of claim 1, wherein the shunt is substantially U-shaped. 3. The target according to claim 2, characterized in that the substantially U-shaped inner peripheral portion of the shunt is formed of a ferromagnetic material and the outer peripheral portion thereof is formed of a non-magnetic material. 4. The target according to any one of claims 1 to 3, characterized in that a support member for supporting the target material is disposed between the target material and the backing plate. The target according to claim 4, characterized in that the support member is made of a wire material.

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