JPS63223168A - Target for sputtering - Google Patents

Abstract

PURPOSE:To easily realize a cylindrical target and to permit effective sputtering, by using split pieces having coupling edges in the direction oblique with the plane orthogonal with the axial center to assemble the target. CONSTITUTION:The target is so constituted that the entire part has a cylindrical shape by alternately laminating the annular split pieces 10a, 10b having the coupling edges 20 in the direction oblique with the plane orthogonal with the axial center of the target in a manner as to connect the coupling edges 20 to each other thereby assembling the target. The adjacent split pieces 10a, 10b are constituted by varying the component compsns. with each other. This target is disposed on a target supporting material 5 and spacers 21, 22 are disposed on the top and bottom end part sides which are then pressed and fixed. The easy assembly of the cylindrical target is thereby permitted even if materials having poor workability are used. Effective sputtering is thus permitted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to surface coatings (such as various magnetic films, wear-resistant films, hard The present invention relates to a sputtering target used when forming a film (film, etc.) by sputtering.

[Prior Art] FIG. 2 is a schematic explanatory diagram showing a typical sputtering apparatus, in which 2 is a vacuum vessel, and 3 is a cylindrical Targetera LA.
l+ loco i yai 41 trz jt o;
6 is a permanent magnet, 7 is a gas introduction means, 8 is a high-voltage power supply, and 9 is a cooling pipe. When using the device 1, an inert gas such as Ar is introduced into the vacuum container 2 by the gas introduction means 7, and the pressure inside the container 2 is reduced to create a negative pressure inert gas atmosphere. A glow discharge is generated by applying a high voltage between 3 (cathode) and substrate 4 (anode), and the plasma positive ions formed here collide with target 3 to evaporate sputtered particles from the surface of target 3. At the same time, this is vapor-deposited on the substrate 4. Cooling water is supplied into the cooling pipe 9, and after passing through the cooling pipe 9, the cooling water passes through the space between the target support material 5 and the cooling pipe 9, and exits from an outlet (not shown). It is structured as follows. The device 1 shown in FIG. 2 is of a so-called magnetron type, and the permanent magnet 6 forms a magnetic field in a direction perpendicular to the voltage to improve discharge efficiency. Various types of sputtering equipment are known in addition to the one shown in Figure 2, and in the following explanation, for convenience, a magnetron type will be used as a representative example, but these are common to all sputtering equipment. must be understood.

As shown in FIG. 2, a sputtering apparatus requires a target in principle, and targets having various structures have been used heretofore. In the past, the most common target shape was the flat plate type, and various improvements have been made to the material and structure of these flat targets, and many of them are already commercially available. . On the other hand, with the diversification of sputtering devices, the shape of the target has also been modified, and cylindrical targets are increasingly being used.

[Problems to be Solved by the Invention] In recent years, the thin films formed are required to have higher performance, such as improved insulation properties and abrasion resistance. Therefore, it has become necessary to improve the purity of the target material or to use a wide range of materials such as alloys and ceramics.

In this case, if the target is a flat plate, it can be manufactured relatively easily regardless of the material, and there are no particular problems. However, when creating a cylindrical target, workability may vary depending on the material used. A problem arises in that it has a significant effect on quality. In particular, when using materials with poor machinability such as ceramics or difficult-to-cut materials such as Cr-Mo alloys, the cost of manufacturing cylindrical targets increases, and in some cases, it may become impossible to manufacture them. You may come across it. Another problem with ceramic monolithic targets is that they become distorted and crack due to high heat during operation.

Furthermore, as shown in FIG. 2, the target 3 is supported by the target support material 5, and the two are generally bonded together with an adhesive, and this adhesive is sputtered and attached to the substrate. There was also the problem that it was carried to the surface and attached as an impurity.

The present invention was made in view of these circumstances, and
The purpose is to provide a structure of a sputtering target that can easily realize a cylindrical target even when using materials with poor workability and that can perform effective sputtering. It is in.

[Means for Solving the Problems] The sputtering target of the present invention that achieves the above object is a sputtering target whose overall shape is cylindrical, and which has a sputtering target in a direction inclined with respect to a plane perpendicular to the axis. The main point is that it is assembled by divided pieces that have connecting edges at the sides.

[Function] As a result of various studies to solve the above-mentioned problems, the present inventors first stacked a plurality of annular divided pieces 10 in the axial direction as shown in FIG. 3 so that the overall shape was cylindrical. Naru target 3
I got the idea that it would be a good idea to compose a . That is, by configuring the cylindrical target 3 by combining a plurality of annular divided pieces 10 that can be formed relatively easily, even if the material is made of a material that would be difficult to manufacture if formed integrally, it can be formed relatively easily. It was hoped that it would be possible to realize a large cylindrical target 3. The configuration shown in FIG. 3 is a typical example, and a separate patent application has been filed because it can achieve the intended purpose.

However, when the present inventors conducted further research, some technical problems still remained to be improved. One of the effects of adopting the configuration shown in FIG. 3 is that by changing the composition and thickness of the laminated divided pieces 10, sputtered particles generated independently from each divided piece 10 are combined and laminated on the substrate. As a result, it is possible to obtain a thin film with a mixed component composition as if an alloy target were used. Therefore, without creating the target 3 using a difficult-to-cut material such as Cr-Mo alloy, you can achieve the desired alloy composition by alternately stacking Cr divided pieces and MO divided pieces in any ratio. A thin film is obtained. At this time, if the structure is such that the annular divided pieces 10 having bonding surfaces in the direction orthogonal to the axis are laminated as shown in FIG. 3, the mixed component composition of the thin film formed on the substrate will be Causes variation. In order to avoid such inconvenience, the cylindrical target 3
Alternatively, it is necessary to provide a mechanism for moving the substrate 4 (see FIG. 2 for the substrate 4) along the axial direction. However, in order to provide the above-mentioned mechanism in a sputtering device, the sputtering device itself becomes complicated and large, and realizing this requires great technical difficulties, which ultimately leads to an increase in costs. occured.

Therefore, as a result of further intensive research, the inventors of the present invention found that, as described above, the mutually connected joint edges of each divided piece were formed in a direction inclined with respect to the plane perpendicular to the axis, and the target or substrate was It was confirmed that the above-mentioned situation could be avoided by rotating it, and the present invention was completed.

That is, each divided piece is configured to be inclined, and such divided pieces are combined to constitute a target whose overall shape is cylindrical, and the cylindrical target (or cylindrical substrate) is rotated around its axis. By rotating the substrate, it was possible to correct variations in the composition of components in the thin film formed on the substrate in the axial direction, and successfully obtain a compositionally uniform thin film.

The present invention will be described in more detail below with reference to Examples, but the Examples below are not intended to limit the present invention.
Any appropriate design changes based on the gist described below are within the technical scope of the present invention.

Embodiment FIG. 1 is a schematic vertical sectional view of an embodiment of the present invention. The basic structure of the sputtering apparatus in the apparatus shown in FIG. 1 is similar to that shown in FIG. 2, so corresponding parts are given the same reference numerals to avoid redundant explanation. In FIG. 1, lla and llb represent an annular shield material, 12 represents an insulating material, and 16 represents a support plate, respectively.
The substrate 4, gas introduction means 7, high-voltage power supply 8, etc. shown in FIG. 2 are omitted for convenience of explanation.

The target 3 according to the present invention includes annular divided pieces 1oa and 1ob having a joint 1i20 in a direction inclined with respect to a plane perpendicular to the axis of the target 3, such that the joint edges 20 are connected to each other. By stacking them alternately and assembling them, the overall shape is cylindrical. Also, adjacent divided pieces 10a.

10b are constructed with mutually different component compositions.

The divided pieces 10a and 10b shown in FIG. 1 have an elliptical appearance when placed on a plane.

The target 3 is placed so as to be fitted onto the target support 5, and the upper end of the target 3 is screwed onto the upper end of the target support 5 with a spacer 21 interposed therebetween. Nut 1
Pressed by 8. Therefore, each divided piece foa, 10b
is fixed by pressing without using adhesive. Incidentally, a spacer 22 similar to the spacer 21 is also arranged on the lower end side of the target 3.

The operating procedure using the apparatus 1 shown in FIG. 1 is almost the same as the apparatus shown in FIG.
(see Figure 2 for details) must be rotated around its axis. A configuration in which the target 3 or the substrate 4 is rotated requires less space and can be achieved relatively easily compared to a configuration in which the target 3 or the substrate 4 is moved in the axial direction.

By performing the operation using the sputtering target 3 according to the present invention, it was possible to correct variations in the composition of the thin film formed on the substrate in the axial direction. The basic structure of the target 3 according to the present invention is a combination of a plurality of divided pieces 10a and 10b, and each divided piece 10a.

Since the tab has a simple shape, it can be made relatively easily regardless of the material, and as a result, even when using a material with poor workability such as ceramics, the target 3 can be made without being limited in size. It can be formed relatively easily. Furthermore, since the target 3 is tightened by pressing the nut 18, there is no need to use adhesive, and compressive stress acts on the divided pieces 10a and 10b, causing the divided piece 10a to tighten.
, 10b can be prevented from cracking, and the adhesive will not be sputtered and become an impurity in the thin film.

On the other hand, each of the divided pieces 10a and 10b is not subject to any particular limitations regarding the specific shape such as dimensions, and the thickness T (length in the axial direction) and the angle θ (
It may be determined as appropriate while correlating the double blades such as the angle of the joint edge 20 with the horizontal plane) and the diameter. However, it is desirable to avoid a shape in which the component composition is completely the same over the entire circumference when an arbitrary axis-perpendicular cross section is taken.

That is, it is preferable not to form the hatched area in FIG. 4 (schematic diagram) in the divided pieces 10a (and 10b).To do this, at least the relationship of equation (1) below should be established in the grooves. You can do it in a folded position.

T≦D tan θ ・(
1) (where D is the diameter of the target 3) If there is a region having the same component composition over the entire circumference as shown in FIG. 4, the divided piece 10a.

Despite the configuration in which the bonding edge 20 of 10b is formed at an angle and the cylindrical target 3 (or substrate 4) is rotated, there is a risk that the thin film portion formed by sputtering from the region will have a single component composition. The high and thin film part is divided into 10 pieces.
This is because it becomes a component of either a or 10b. However, sputtered particles tend to diffuse in the vertical direction as well, and if a configuration in which the target or substrate is moved slightly in the axial direction is also used, these disadvantages can be solved, so there is no problem. Furthermore, from the point of view of forming a thin film as uniformly as possible, each divided piece 10a.

It is recommended that the thickness T of the tab be as small as possible, and preferably about 1 to 10 mm, for example. Further, by setting the thickness T to this level, the inclination angle θ can be made small, and there is an advantage that the work of creating the divided pieces 10a and 10b becomes easier.

Next, the component composition ratio of the thin film formed on the substrate (separated piece 1
When adjusting the mixing ratio of component A of 0a and component B of divided piece 10a to a certain value, each divided piece 10a, 10b
The relationship between the thickness TA, ``ra'' and the inclination angle θ will be specifically explained.

First, the ratio of the mixed component composition of the thin film formed on the substrate is A
:B=1:1 will be explained based on a specific example. In this case, as shown in FIG. 5 (schematic diagram), the thicknesses TA and T of the divided pieces 10a and 10b are the same,
If the diameter of the target 3 is D, the inclination angle θ is as follows (2
) is determined by the formula.

υ The component composition ratio of the thin film formed when actually operated with the above settings is also shown in FIG. 5 in correspondence with the axial direction of the cylindrical target 3.

The ratio of composition A to the total composition of the thin film at this time was 50±16.5 (%).

Next, a case will be described in which the ratio of the mixed component composition of the thin film formed on the substrate is A:B=1:3. In this case, as shown in FIG. 6, the thickness TA of the divided piece 10a is set to 2/7 of the thickness T6 of the divided piece 10b, and each inclination θ is set as follows (3
) is determined according to the formula.

TA /2 + TB θ= jan-' □ ... (3) The composition ratio of the mixed components of the thin film formed when actually operating with the above settings is made to correspond to the axial direction of the cylindrical target 3. It is also shown in Figure 6. In addition, the ratio of composition A to the composition in the thin film at this time is 24.5 ± 8.5 (%)
Met.

As in the specific example described above, the thickness TA of the divided pieces 10a and 10b
, TB, the inclination angle θ, and the diameter, the ratio of components A and B in the thin film can be set arbitrarily. However, the above purpose does not exclude that two or more different divided pieces 10 are included in any axis-perpendicular cross section.

In the embodiment shown in FIG. 1, the elliptical divided piece 10a is
, 10b are combined to form a cylindrical overall shape, the shapes of the divided pieces 10a, 10b and the target 3 are not limited to those shown in FIG.

For example, as shown in FIG. 7, a substantially cylindrical target 3 may be formed using circular annular divided pieces 10c (the outer circumferential surface of the target 3 has a step-like shape), or after being combined. A configuration in which the overall shape of the target 3 is a rectangular tube shape such as a hexagonal tube shape is also included in the technical scope of the present invention. Further, although FIG. 1 shows the case where the cylindrical target 3 according to the present invention is applied to a magnetron type sputtering device, the cylindrical target 3 of the present invention is not limited to application only to a magnetron type sputtering device. As already stated.

[Effects of the Invention] As described above, according to the present invention, not only can it be easily realized even when using materials with poor workability, but also sputtering can be performed effectively. The target was achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view showing an embodiment of the present invention, FIG. 2 is a schematic explanatory view showing a typical sputtering device, FIG. 3 is a schematic explanatory drawing showing an example of an improved sputtering device, and FIG. The figure is a schematic diagram of the divided piece 10a, FIGS. 5 and 6 are diagrams for explaining the case of adjusting the component composition ratio of the thin film, and FIG. 7 is a schematic explanatory diagram showing one embodiment of the target 3. . DESCRIPTION OF SYMBOLS 1... Sputtering apparatus 2... Vacuum container 3... Target 4... Substrate 5... Target support material 6... Permanent magnet 9... Cooling pipe 10.10a
, 10b, 1Oc---Divided piece 18...Tighten with a nut 21.22...Spacer Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] In sputtering targets whose overall shape is cylindrical,
1. A sputtering target, characterized in that the sputtering target is assembled by divided pieces having connecting edges in a direction inclined with respect to a plane perpendicular to the axis.