JPH0692632B2 - Flat plate magnetron sputtering system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flat plate magnetron sputtering apparatus in which the shape of a magnet on the back surface of a target is improved.

[Prior Art] In recent thin film forming techniques, it is often desired to obtain a thin film by sputtering a complex system compound composed of two or more kinds of elements. To give a few examples, there are so-called Y-Ba-Cu-O-based compounds such as Y ₁ Ba ₂ Cu ₃ O _7-X in oxide superconductors. In the field of oxide superconductors, in addition to these, La-Ba-Cu-O system, Bi-Sr-Ca-Cu-
Numerous systems such as O-based and Tl-Ca-Ba-Cu-O-based are known, and it is well known that they are all complex compounds. Compounds of such a complicated system are not limited to the field of oxide superconductors, but are also applicable to the field of magnetic materials, for example, sendust that is often used in this field is a typical example. In addition, In ₂ O ₃ + SnO ₂ (ITO), In ₂ O
₃ and ZnO are examples.

A flat plate magnetron sputtering apparatus, which is excellent in mass productivity and easy to have a large area, is generally used for forming thin films of these compounds.

FIG. 10 shows a schematic front sectional view of a conventional flat plate magnetron sputtering apparatus.

The vacuum container 1 is exhausted by the exhaust system 2. The gas introduction system 5 is
It consists of a flow control valve 7 and a gas cylinder 6. In this conventional example, one system of gas introduction system is used, but there is also an apparatus using multiple systems of gas introduction system as needed. Target electrode
Reference numeral 10 includes a target 12 and a target holder 11 that holds the target 12. A magnet is housed inside the target holder 11. This magnet is the inner ring magnet 10
1 and an outer ring-shaped magnet 102, both of which are fixed to a yoke 401. The target 12 and the magnets 101, 102 are cooled by the refrigerant 13 flowing in the target holder 11. The means 14 for supplying power is composed of a high frequency power supply 15 and an impedance matching device 16, and supplies this power to the target electrode 10 to generate plasma in the vacuum container 1. Reference numeral 8 is a target shield, and 9 is an insulating material.

The positive ions in the plasma bombard the surface of the target 12 to sputter the target atoms, and the sputtered target atoms are at a substrate holder 3 (usually at ground potential or floating potential) opposite to the target 12. Depending on the type, an arbitrary voltage can be applied.) A film is deposited on the surface of the substrate 4 attached thereto. At this time, the plasma is focused on the magnetron region 21 near the surface of the target 12 by the magnets 101 and 102 on the back surface of the target. As described above, in the flat plate magnetron sputtering apparatus, the high-density plasma is converged to improve the sputtering efficiency and increase the film formation rate.

FIG. 11 is a front sectional view showing a structural example of a magnet in the conventional apparatus shown in FIG. This magnet is arranged on the back surface of the circular target, and the inner annular magnet 103
And the annular magnet 104 on the outside thereof, and both are fixed to the yoke 402. Magnetic field lines 201 generated by this magnet
Is as shown in FIG. 11, and the locus 301 connecting the points where the lines of magnetic force are parallel to the target surface is a cylindrical surface. The central axis of the locus 301 having a cylindrical surface is perpendicular to the target surface. Since the density of plasma is highest in the region where the electric field and the magnetic field are orthogonal to each other, the plasma converges around this cylindrical locus 301.

[Problems to be Solved by the Invention] In the production of a thin film by sputtering, negative ions having a large mass are easily generated depending on the target material. For example, when a target such as the above-mentioned oxide superconductor or ITO is used as a target and is sputtered, negative oxygen ions are easily generated. The negative ions are accelerated from the target toward the substrate by the electric field between the electrodes, bombard the film deposited on the substrate, change the composition of the thin film, destroy the crystal of the thin film, and in extreme cases, the substrate. It causes various damages such as not attaching the thin film to the whole surface or a part of the surface.

As described above, in the conventional flat panel magnetron sputtering device, the plasma is focused on the magnetron region by the magnet placed on the back surface of the target, and only the target in this portion is sputtered. Therefore, the generation of negative ions is also generated from this portion. Becomes Therefore, the film portion that is damaged as described above is on the substrate facing the magnetron region, and the thin film in the portion facing the center of the target is relatively not damaged. However, the portion which is not damaged is extremely narrow, and in order to obtain this portion widely, the inner diameter of the magnetron region must be increased. In the conventional flat plate magnetron sputtering device, the diameter of the magnet must be increased in order to increase the inner diameter of the magnetron region, and therefore the target electrode shown in FIG.
There was a problem that the size of the device itself increased by 10 as well.

An object of the present invention is to provide a flat plate magnetron sputtering apparatus capable of enlarging the diameter of the magnetron region and widening a substrate portion which is not damaged by negative ion bombardment without enlarging the magnet on the back surface of the target. Is.

[Means for Solving the Problems] In order to achieve the above object, in the flat plate magnetron sputtering apparatus according to the present invention, the magnet on the back surface of one flat plate-shaped target is configured as follows. That is, the locus connecting the points where the lines of magnetic force generated by the magnet are parallel to the target surface is tapered in the direction from the magnet to the target.

As such a magnet, for example, an inner magnet magnetized in a direction perpendicular to the target surface and an annular outer magnet arranged around the inner magnet and having a magnetization direction opposite to that of the inner magnet are used. Then, the distance from the outer magnet to the target surface is made larger than the distance from the inner magnet to the target surface.

Another example of the magnet is an inner magnet magnetized in a direction perpendicular to the target surface, and an annular outer magnet arranged around the inner magnet and having a magnetization direction opposite to that of the inner magnet. , The target side surface of the outer magnet is inclined so that its outer circumference is farther from the target than the inner circumference, and the inner circumference of the outer magnet is kept closer to the target than the inner magnet.

As another example of the magnet, an inner magnet magnetized in a direction perpendicular to the target surface and an annular outer magnet arranged around the inner magnet and magnetized in a radial direction parallel to the target surface. The outer magnetic pole of the outer magnet is opposite to the target magnetic pole of the inner magnet.

[Operation] When the locus connecting points where the lines of magnetic force generated by the magnet are parallel to the target surface (hereinafter referred to as the parallel point locus) spreads in a taper shape in the direction from the magnet to the target, The inner diameter of the magnetron region can be changed by appropriately adjusting the distance to the magnet. That is, as the target is separated from the magnet, the intersecting position of the parallel point locus and the target surface moves toward the target peripheral direction, and as a result, the inner diameter of the magnetron region increases.

In the conventional magnet configuration as shown in FIG. 11, the diameter of the parallel locus does not change even at a position away from the magnet. However, according to the magnet configuration of the present invention, the diameter of the parallel point locus increases as the distance from the magnet increases, and even if a magnet having the same outer shape as the magnet in the conventional apparatus is used, the target surface slightly away from the magnet has a conventional shape. The inner diameter of the magnetron region can be made larger than that. Therefore, it is possible to obtain a wide substrate portion which is not damaged by the negative ion impact without increasing the diameter of the magnet itself. Further, since the magnet itself does not have to be large, it is not necessary to upsize the device.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

The configuration of the entire device is the same as the configuration of the conventional device shown in FIG. 10, and therefore illustration and description thereof will be omitted.

1 to 9 are front sectional views showing various embodiments of magnets installed on the back surface of the target of the flat plate magnetron sputtering apparatus of the present invention. Both are arranged on the back surface of the circular target. In the figure, 105 to 122
Is an inner magnet and an outer magnet, 403 to 411 are yokes connecting the inner magnet and the outer magnet, 421 to 423 are yokes attached to the annular inner magnet, 202 to 207 are magnetic force lines, and 302 to 307 are parallel point loci.

The magnet shown in FIG. 1 is composed of a cylindrical inner magnet 105 magnetized in a direction perpendicular to the target surface, and an annular outer magnet 106 arranged around the magnet inner side and magnetized in the opposite direction. Both are fixed to the yoke 403. Outer magnet 106 yoke
The height from 403 is lower than that of the inner magnet 105. Therefore, comparing the distance from the target surface 12a to the S pole of the inner magnet 105 and the distance from the target surface 12a to the N pole of the outer magnet 106, the latter is larger than the former. The magnetic force lines 202 generated by this magnet are as shown in the figure, and the parallel point locus 302 is tapered in the direction from the magnet toward the target 12. Since the magnet is circular in this example, the parallel point locus 302 is roughly a conical surface that opens upward. As the target 12 is moved upward in the figure and the target surface 12a is separated from the magnet, the position where the parallel point locus 302 and the target surface 12a intersect becomes closer to the peripheral portion of the target. Therefore, the inner diameter of the magnetron region can be adjusted by adjusting the distance between the target 12 and the magnet.

In a conventional flat panel magnetron sputtering apparatus using a magnet, for example, the diameter of the erosion center is about 50 mm for a target of 100 mm in diameter.
If the magnet shown in the figure is used, the diameter of the erosion center can be increased to any value from 50 mm to nearly 100 mm even if the magnet with the same outer diameter is used. Therefore, it is possible to obtain a wide substrate portion which is not damaged by the negative ion impact without enlarging the outer shape of the magnet itself.

The magnet shown in FIG. 2 is an example in which an annular inner magnet 107 is used instead of the cylindrical inner magnet 105 shown in FIG. The ring-shaped inner magnet is used for a relatively large target.

The magnet shown in FIG. 3 corresponds to the annular inner magnet 107 (shown in FIG.
In the figure, it is an example in which a yoke 421 is attached on top of 109). Although the magnetic force line and its parallel locus are not shown in FIG. 3,
These are similar to FIGS. 1 and 2.

The magnet of FIG. 4 uses an outer magnet 112 having an inclined upper surface, instead of the lower outer magnet 106 of FIG. The annular outer magnet 112 has a magnetization direction opposite to that of the inner magnet 111, and the target side surface 112a has an outer circumference 11 thereof.
The inclined surface 2b is farther from the target than the inner circumference 112c. The height of the inner circumference 112c from the yoke 406 is the same as that of the inner magnet 111. The height of the inner circumference 112c may be lower than that of the inner magnet 111, and in short, may be higher than that of the inner magnet 111. With such a magnet structure, the parallel point locus 304 similar to that shown in FIG. 1 can be obtained.

The magnet in FIG. 5 is an example in which an annular inner magnet 113 is used instead of the cylindrical inner magnet 111 in FIG.

The magnet shown in FIG. 6 corresponds to the annular inner magnet 113 (shown in FIG.
In the figure, the yoke 422 is attached on top of 115). The magnetic force lines and their parallel loci in FIG. 3 are the same as those in FIGS. 4 and 5.

The magnet shown in FIG. 7 is a cylindrical inner magnet 117 magnetized in a direction perpendicular to the target surface, and an annular outer magnet arranged around the inner magnet 117 and magnetized in a radial direction parallel to the target surface. It is composed of a magnet 118. The magnetic pole on the outer circumference of the outer magnet 118 is an N pole, which is the inner magnet 117.
It is opposite to the magnetic pole on the target side, that is, the S pole. With such a magnet structure, the parallel point locus 306 similar to that shown in FIG. 1 can be obtained. If anything, the parallel point locus 306 of this type of magnet has a larger degree of taper spread than the parallel point locus 302 of FIG.

In FIG. 7, the height of the outer magnet 118 from the yoke 409 is
Although the height is lower than that of the inner magnet 117, the height may be the same as that of the inner magnet 117. The yoke 409 is for fixing both magnets and for preventing the magnetic field from leaking to the back surface of the magnet (the lower surface in the figure). However, since the magnetic force line 206 as shown is obtained without the yoke 409, Inner magnet 117 and outer magnet 11
The yoke 409 may be omitted as long as it does not interfere with the fixing of 8.

The magnet of FIG. 8 is an example in which an annular inner magnet 119 is used instead of the cylindrical inner magnet 117 of FIG.

The magnet shown in FIG. 9 corresponds to the annular inner magnet 119 shown in FIG.
The figure shows an example in which a yoke 423 is attached on top of (121). The lines of magnetic force and the loci of parallel points in FIG. 9 are the same as those in FIGS. 7 and 8.

In addition, in FIGS. 1 to 9, the N pole and the S pole may be completely reversed, and in this case, the directions of the lines of magnetic force are only reversed, and the same effect is obtained.

Although the above embodiments have described a magnet configuration for a circular target, the present invention is applicable to other types of targets. For example, in the case of a rectangular target, a prismatic inner magnet and an outer magnet having a square outer shape may be used.

[Advantages of the Invention] In the present invention, the magnet is configured such that the locus connecting the points where the lines of magnetic force generated by the magnet on the back surface of the target are parallel to the target surface spreads in a taper shape in the direction from the magnet to the target. Therefore, the inner diameter of the magnetron region can be increased without increasing the size of the magnet itself.
As a result, it is possible to obtain a wide substrate portion that is not damaged by the impact of negative ions.

[Brief description of drawings]

1 to 9 are front sectional views showing various examples of magnets used in the apparatus of the present invention, FIG. 10 is a schematic front sectional view of a conventional flat plate magnetron sputtering apparatus, and FIG. 11 is It is a front sectional view of a magnet in a conventional device. 12 …… Target 105 …… Inner magnet 106 …… Outer magnet 202 …… Magnetic field line 302 …… Parallel locus

Claims (4)

[Claims] 1. A magnet is arranged on the back surface of a flat plate-shaped target to generate high-density plasma in the vicinity of the surface of the target to sputter the target, and a film is formed on a substrate facing the target. In the flat plate magnetron sputtering apparatus, the magnet is configured such that a locus connecting points where the magnetic force lines generated by the magnet are parallel to the target surface spreads in a taper shape in a direction from the magnet to the target. Flat plate magnetron sputtering system. 2. The magnet comprises an inner magnet magnetized in a direction perpendicular to the target surface, and an annular outer magnet arranged around the inner magnet and having a magnetization direction opposite to that of the inner magnet. The sputtering apparatus according to claim 1, wherein the distance from the outer magnet to the target surface is larger than the distance from the inner magnet to the target surface. 3. The magnet comprises an inner magnet magnetized in a direction perpendicular to the target surface, and an annular outer magnet arranged around the inner magnet and having a magnetization direction opposite to that of the inner magnet. 2. The target-side surface of the outer magnet is inclined so that its outer circumference is farther from the target than its inner circumference, and the inner circumference of the outer magnet is closer to the target than the inner magnet. Sputtering equipment. 4. The magnet comprises an inner magnet magnetized in a direction perpendicular to the target surface, and an annular outer magnet arranged around the inner magnet and magnetized in a radial direction parallel to the target surface. The sputtering apparatus according to claim 1, wherein the magnetic pole on the outer circumference of the outer magnet is opposite to the magnetic pole on the target side of the inner magnet.