TW201634724A - Target material - Google Patents

Abstract

The present invention provides a novel target material which expands the erosion area generated by sputtering, even when a long strip of target material is used, thereby increasing efficiency and reducing production cost. The target material of the present invention is an elongated strip of target material whose sputtering surface and the back of the sputter surface are smooth. The target material is bonded to a back plate, whose surface directly bonded to the target material is smooth, by a bonding material. Plate-like splitters are disposed on two longitudinal ends of the target material, and between the target material and the back plate, on the outer circumference of the two ends in the longitudinal direction of the target material. The target material and the back plate are bonded together by the splitters and the bonding material.

Description

Target

This invention relates to a target for use in a magnetron sputtering process.

A sputtering method widely known as a thin film forming technique for a wiring film or the like of an electronic component is a target material in which a base material of a thin film is disposed in a vacuum chamber, and is in phase with the target material. A method of forming a substrate on the surface of the substrate by arranging a substrate or the like on the surface of the crucible. Specifically, the method is: introducing a rare gas into a vacuum chamber, applying direct current power or alternating current power to the target material, causing a glow discharge on the surface of the target material, and driving the target out with the rare gas ions. The atoms on the surface of the material form a thin film on the surface of the substrate or the like, and the method is widely used industrially.

In the sputtering method, the magnetron sputtering method is to arrange a magnet unit on the back surface of the target material, generate a tunnel-shaped magnetic field line on the surface of the target material, and capture the surface generated by the glow discharge on the surface of the target material. The method of electrons to increase electron density. The magnetron sputtering method has a characteristic that a stable glow discharge can be generated with a low rare gas pressure, and an excellent film quality can be achieved at a high film formation rate, and thus it is particularly widely used.

As the shape of the target material used in the sputtering method, there are a flat circular plate, a flat rectangular shape, a cylinder, and the like, and in the manufacturing apparatus of a flat panel display represented by a liquid crystal display, flat sputtering is widely used. The long strip-shaped target material of the surface (for example, refer to Non-Patent Document 1).

A magnet unit suitable for use in a magnetron sputtering apparatus using the elongated target material is typically configured as follows: a long side of a center of a rectangular shaped yoke (yoke) disposed in parallel on a target material A magnet (central magnet) is disposed in the direction, and a magnet (outer circumference magnet) is also disposed on the entire circumference of the outer circumference around the shape of the magnet. In the magnet unit, the central magnet is set to the N pole, and the outer peripheral magnet is set to the S pole, so that a tunnel-shaped arch line of magnetic force is drawn when the surface of the target material is observed from above (for example, see Patent Document 1). ).

Further, in the magnet unit, there is known a problem in that the horizontal portion of the magnetic field line on the surface of the target material is narrowed in the vicinity of both end portions in the longitudinal direction of the target material, so that the target material is eroded (hereinafter Also known as erosion, it is locally narrowly and deeply advanced, and the utilization efficiency of the target material is lowered. The problem causes an increase in manufacturing cost when, for example, the manufacture of a flat panel display using a target material containing an expensive rare metal such as Mo to form a thin film.

In order to solve the problem that the utilization efficiency of the target material is lowered, attention has been paid to the shape of the target material, and a structure has been proposed in which only the vicinity of both end portions in the longitudinal direction of the target material is locally thickened. On the other hand, in order to solve the problem that the utilization efficiency of the same target material is lowered, focusing on the magnetic flux at the time of film formation, it has been proposed to fix a magnetic shunt having a triangular profile to a long-shaped target. The structure in a predetermined region in the longitudinal direction of the material. According to the configuration, the magnetic field generated on the surface of the target material is locally weakened, and the shape of the plasma is changed, whereby the utilization efficiency of the target material can be improved in terms of expanding the erosion region of the target material. It is excellent (for example, refer to Patent Document 2). [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 7-34244 (page 5, FIG. 1) [Patent Document 2] Japanese Patent Laid-Open Publication No. 2012-201910 (page 10, FIG. 3) [Non-Patent Literature ]

[Non-Patent Document 1] Shahe Hiroshi, "The Status and Problems of Large-Scale Sputtering Devices for Flat Panel Display (FPD) Manufacturing" J. Vac. Soc. Jpn. (Vacuum), pp. 28 - 31

[Problems to be Solved by the Invention] In the method of locally thickening only the both end portions in the longitudinal direction of the target material, a step is formed in comparison with the target material of the flat plate as a simple shape. There is a need to prepare a dedicated mold or a hot isostatic pressing (HIP) tank, so that there is an increase in manufacturing cost. Further, when a step is formed with a target material of a flat plate having a simple shape, it is necessary to perform a cutting process on the target material, so that the processing time becomes long, and a large amount of machining chips are generated, and the yield is lowered. Therefore, there is a problem that the manufacturing cost of the target material is increased. Further, in the method of fixing a magnetic splitter having a triangular profile in the longitudinal direction of the elongated target material, when the target material is placed on an existing sputtering apparatus, there is a need for a large-scale addition. Repair situation. Further, the intensity or distribution of the magnetic flux generated from the magnet unit at the time of sputtering may be uneven, and the eroded area due to sputtering may become uneven.

An object of the present invention is to solve the above problems and to provide a novel target which has a high utilization efficiency and a low manufacturing cost, even if a long target material is used, and an erosion region due to sputtering is enlarged. [Means for solving the problem]

The present inventors have studied a method of improving the utilization efficiency by uniformizing the strength and distribution of the magnetic flux generated from the long target material by the magnet unit and suppressing uneven erosion of the target material. As a result, it has been found that by setting the joint surface of the target material and the backing plate into a flat shape, a shunt of a specific shape is inserted at a specific position of the joint surface to make the target material. The utilization efficiency is greatly improved to achieve the present invention.

That is, the present invention is an invention of a target material in which a long-shaped target material having a flat shape on a sputter surface and a back surface of the sputter surface, and a back sheet having a flat surface joined to the target material Joining via a bonding material, and at both end portions in the longitudinal direction of the target material, between the target material and the backing plate, along the outer peripheral portion of both end portions of the longitudinal direction of the target material A plate-shaped splitter is disposed, and the target material and the backing plate are joined via the splitter and the bonding material. The splitter suitable for use in the present invention is preferably substantially U-shaped. Further, it is preferable that the splitter includes a strong magnet in an inner peripheral portion of a substantially U shape and a non-magnetic body in an outer peripheral portion.

Preferably, the target of the present invention is provided with a support member for supporting the target material between the target material and the backing plate. Further, it is preferable that the support member uses a wire. [Effects of the Invention]

Since the target material of the present invention uses a long-shaped target material, the manufacturing cost is low, and the erosion region of the target material can be enlarged, so that high utilization efficiency can be obtained, and the technique suitable for film formation can be obtained.

As described above, an important feature of the present invention resides in a configuration in which a joint surface of a target material and a backing plate is formed into a flat shape, a splitter is inserted at a specific position of the joint surface, and joined by a bonding material. Specifically, as shown in FIG. 1, the target material of the present invention is a target material 1 having a flat shape on a sputter surface and a back surface thereof, and a back sheet 2 having a flat shape on a surface joined to the target material 1. A target joined by the bonding material 3 . Further, at both end portions in the longitudinal direction of the target material 1, a plate-shaped splitter 4 is disposed between the target material 1 and the backing plate 2 along the outer peripheral portion of both end portions in the longitudinal direction of the target material 1. The target material 1 and the backing plate 2 are joined to the bonding material 3 via the splitter 4 in the cross section in the longitudinal direction. Hereinafter, the target of the present invention will be described in detail.

The target of the present invention has a flat shape in which the sputtering surface of the target material and the back surface of the sputtering surface are formed without unevenness or step. Therefore, the target material used in the present invention does not require a complicated mold or HIP can, the processing of the target material 1 is simple, and the chips generated by the processing are also minimized, so that the target material can be suppressed. manufacturing cost. Moreover, since the back sheet used in the present invention has a flat shape similarly to the sputtering surface and the back surface of the target material, it is not necessary to perform special processing similarly to the target material, and the manufacturing cost can be suppressed.

In the present invention, a plate-like portion is disposed between the target material 1 and the backing plate 2 at both end portions in the longitudinal direction of the target material 1 at both end portions in the longitudinal direction of the target material 1. Road device 4. Thus, the target of the present invention achieves the following two effects. In the magnet unit used in the long-shaped target material, the magnetic lines of force at both ends in the longitudinal direction form a substantially U-shaped tunnel-shaped arch. In the region, the horizontal area of the magnetic lines of force is particularly narrow, and the strength of the magnetic field varies depending on the location, so that the erosion of the target material is locally narrow and deep. Therefore, in the present invention, by providing a splitter in a portion along the outer peripheral portion of both end portions in the longitudinal direction of the target material as described above, the magnetic flux can be controlled to improve the utilization of the target material. effectiveness. Further, the target of the present invention can particularly effectively control the magnetic lines of force in the vicinity of the surface of the target material 1 by providing the splitter 4 between the target material 1 and the backing plate 2.

The splitter to which the present invention is applied may be a ferromagnetic material, and if it is a pure metal, for example, Fe, Ni, Co, or the like may be mentioned, and if it is an alloy, for example, permalloy, SUS 430, etc. may be mentioned. Alloys and the like can be appropriately selected depending on the magnetic properties required in the sputtering conditions. Further, the splitter to which the present invention is applied is formed into a shape of an outer peripheral portion along both end portions in the longitudinal direction of the target material as shown in Fig. 2(a) so as to be along both ends in the longitudinal direction of the target material. The outer peripheral part of the department is configured. The size and thickness of the splitter to which the present invention is applied can be set in accordance with the distribution of magnetic lines of force generated from the magnet unit and the strength of the magnetic field. It is also possible to locally change the thickness or to bond materials having different magnetic properties.

In the present invention, as shown in FIG. 2(b), it is preferable that the shape of the splitter 4 is substantially U-shaped, and the U-shaped shape at both end portions in the longitudinal direction of the target material is disposed. U shape. The magnetic lines of force generated at the both end portions in the longitudinal direction of the magnet unit of the sputtering apparatus are formed to have a substantially U-shaped tunnel shape when the target is viewed from above, and the substantially U shape is matched by the shape of the tunnel. The word-shaped splitter can enlarge the horizontal area of the magnetic lines of force and reduce the unevenness of the local magnetic field strength, thereby further improving the utilization efficiency of the target material. Further, when the shape of the splitter 4 is substantially U-shaped, as shown in FIG. 2(c), a non-magnetic body can be inserted into the inner peripheral portion of the ferromagnetic body, thereby ensuring the pair of branches. The inner peripheral portion of the device performs the function of supporting.

In the present invention, as shown in FIG. 2(d), it is preferable that the substantially U-shaped inner peripheral portion of the splitter 4 includes a ferromagnetic body, and the outer peripheral portion includes a non-magnetic body. When the target material 1 and the backing plate 2 are joined via the bonding material 3, it is necessary to accurately arrange the substantially U-shaped splitter 4 with respect to a predetermined position at both end portions in the longitudinal direction. At this time, it is preferable that the outer peripheral portion of the substantially U-shaped splitter 4 has the same outer shape as the outer peripheral portion of the target material 1 so as to be easily positioned. Further, it is preferable to use a splitter 4 having a structure in which the inner peripheral portion of the substantially U-shaped splitter 4 is a substantially U-shaped ferromagnetic body having a function of a splitter, and is substantially U-shaped. The outer peripheral portion of the router 4 is a non-magnetic body, and the inner peripheral portion and the outer peripheral portion are joined in parallel. Thereby, the positioning at the time of joining can be performed accurately and quickly.

Further, the outer peripheral portion of the splitter 4 has a contour along the outer peripheral portion of the target material, and may have a function of supporting the inner peripheral portion of the substantially U-shaped ferromagnetic material, and is preferably a non-magnetic body. This is because if the outer peripheral portion of the splitter 4 has strong magnetism, the function of the splitter 4 may be broken depending on the sputtering conditions. Further, when the shape of the splitter 4 is substantially U-shaped, as shown in FIG. 2(e), a non-magnetic body may be inserted into the inner peripheral portion of the ferromagnetic body, thereby ensuring the pair of splitters. The inner peripheral part supports the function. The material of the non-magnetic material used for the outer peripheral portion of the splitter 4 can be suitably selected from the group consisting of Cu, Al, or an alloy containing 50% by mass or more of the metal having a high thermal conductivity and easy processing.

In the present invention, it is preferable to arrange the support member 5 illustrated in Fig. 1 between the target material 1 and the backing plate 2. Thus, the target of the present invention can keep the distance between the target material 1 and the backing plate 2 constant. Further, it is preferable that the support member 5 to which the present invention is applied has a thickness that is the same as the thickness of the splitter 4, whereby the interval between the target material 1 and the backing plate 2 can be kept constant while The thickness of the bonding material 3 becomes uniform, so that stable bonding can be achieved. Further, when the splitter 4 is disposed at both end portions of the backboard 2, the support member 5 is disposed in advance so that the inner end portion of the splitter 4 reaches the position to be placed. The positioning of the splitter 4 can be performed accurately and quickly. Since the joint surface of the target material and the back sheet which are applied in the present invention is a flat shape having no unevenness or step difference throughout the entire length in the longitudinal direction, the above is a particularly effective means.

In the present invention, it is preferred to use a wire as the support member 5. At this time, the volume of the wire serving as 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, respectively, and the arrangement bonding material 3 between the target material 1 and the backing plate 2 is lowered. The occupancy of the support member 5 at the position. Thereby, the target material of the present invention can hold the bonding material 3 with a uniform thickness while maintaining the interval between the target material 1 and the backing plate 2, thereby ensuring bonding strength or maintaining thermal conductivity. In addition, as the material of the support member 5, any material can be applied as long as it has high thermal conductivity, easy processing such as cutting, and a material having moderate rigidity. Further, as shown in FIG. 1, the support member 5 may be arranged in parallel with each other at a predetermined interval in the longitudinal direction with respect to the longitudinal direction of the target material 1, or may be arranged in parallel at a predetermined interval along the longitudinal direction of the target material 1. . [Examples]

First, prepare: Mo target material, the sputter surface and the back surface of the sputter surface have a flat shape with a thickness of 16 mm × width 180 mm × length 2650 mm, purity of 99.95%; back plate, and the target The surface of the material material joined to the back surface has a flat shape; and the splitter is provided with Ni in the strong magnet portion shown in FIG. 2(d) and Cu in the non-magnetic portion, and has a thickness of 0.3 mm. Next, as shown in FIG. 1, the points are arranged along the outer peripheral portions of both end portions in the longitudinal direction of the target material 1 between the target material 1 and the back sheet 2 at both end portions in the longitudinal direction of the target material 1. The road 4 is joined to the target material 1 and the backing plate 2 via the splitter 4 and the bonding material 3 to produce the target of the present invention. Further, a target material as a comparative example was produced as follows: the target material and the back sheet were joined only by the bonding material without inserting the splitter.

Each of the targets obtained as described above was placed in a magnetron sputtering apparatus manufactured by Ulvac Co., Ltd., and an alternating current power source was used, and Ar gas was used as a sputtering gas at a gas pressure of 0.8 Pa. The sputtering test was carried out under the condition of an input power of 80 kW. On the way, the sputtering was interrupted several times, and the cumulative power before the remaining thickness of the target material of the deepest portion was 1 mm or less, that is, the power [kW] × the sputtering time [hr]. The results are shown in Table 1.

[Table 1]

When a sputtering test is performed using a target material of a comparative example in which a target material and a backing plate are joined only via a bonding material, the cumulative power before the corrosion progresses and the remaining thickness of the target material is 1 mm or less is 15,000 kW· Hr. On the other hand, when the sputtering test is performed using the target of the present invention in which a splitter having a specific shape is inserted at a specific position, the cumulative power before the corrosion progresses and the remaining thickness of the target material reaches 1 mm or less is 19,000 kW. · hr, which is greatly increased with respect to the comparative example. This means that the life of the target is greatly improved, so that the effectiveness of the target of the present invention can be confirmed.

1‧‧‧target material
2‧‧‧ Backplane
3‧‧‧ joining materials
4‧‧‧Splitter
5‧‧‧Support members

Fig. 1 is a schematic view showing an example of a target of the present invention. 2(a) to 2(e) are schematic views showing an example of a shape of a splitter to which the target of the present invention is applied.

1‧‧‧target material

2‧‧‧ Backplane

3‧‧‧ joining materials

4‧‧‧Splitter

5‧‧‧Support members

Claims (5)

A target material in which a long-shaped target material having a flat shape on a sputter surface and a back surface of the sputter surface, and a back sheet having a flat surface joined to the target material are joined via a bonding material. The target material is characterized in that the outer peripheral portion of both end portions in the longitudinal direction of the target material is between the target material and the back plate at both end portions in the longitudinal direction of the target material. A plate-shaped splitter is disposed, and the target material and the backing plate are joined via the splitter and the bonding material. The target of claim 1, wherein the splitter has a substantially U shape. The target according to claim 2, wherein the substantially U-shaped inner peripheral portion of the splitter includes a ferromagnetic body, and the outer peripheral portion includes a non-magnetic body. The target according to any one of claims 1 to 3, wherein a support member supporting the target material is disposed between the target material and the backing plate. The target of claim 4, wherein the support member comprises a wire.