JPH04221070A - Magnetron cathode - Google Patents

Abstract

PURPOSE:To generate plasma having uniform density in a wide range by surrounding the outer peripheral parts in the regions of a plurality of pieces of electromagnets impressed with AC by a magnet and performing scan in a magnetic field wherein electromagnetic force is transferred in the internal region of the specified magnetic field. CONSTITUTION:In a magnetron cathode 1 for generating a plasma discharge region in the ambient space by action of a magnetic field, a plurality of electromagnets 2 constituted of a platelike conductor 2a and a coil winding part 2b are provided. A permanent magnet 3 surrounding the outer peripheral parts of the electromagnets is arranged in at least one part of these outer peripheral parts. AC having the prescribed phase relation such as three-phase AC is impressed to the electro-magnets 2. A transferred magnetic field is formed while performing scan by the electromagnets 2 in the internal region of the specified magnetic field which is formed by the permanent magnet 3 and fixed. A transferred discharge region is formed by this transferred magnetic field. Plasma which is uniform and high in density is generated in a wide range. Thereby sputtering and etching are enabled which are uniform and good in efficiency.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron cathode, and more particularly to a magnetron cathode used as an electrode for processing a substrate by generating magnetron discharge in sputtering equipment, dry etching equipment, and the like.

0002

2. Description of the Related Art Regarding the structure of a conventional magnetron cathode (hereinafter referred to as cathode), an example applied to a sputtering apparatus will be described with reference to FIGS. 8 to 10.

In FIG. 8(A), a cathode 101 has permanent magnets 102 and 103. For example, the upper end of the permanent magnet 102 is an S pole, and the upper end of the permanent magnet 103 is an N pole,
As shown in FIG. 8(B), the permanent magnet 102 is
3 are arranged so as to surround it. The lower portions of the permanent magnets 102 and 103 are connected by a yoke 104. Due to this arrangement, lines of magnetic force 105 are formed from the permanent magnet 103 to the permanent magnet 102. A target 106 is arranged above the permanent magnets 102 and 103. A magnetic field is formed by the permanent magnets 102 and 103 on the upper surface of the target 106, and as a result, a magnetron discharge is generated around the magnetic field. Figure 8
In the plan view of (C), reference numeral 107 indicates a magnetron discharge region on the upper surface of the target 106. In this conventional cathode 101, the permanent magnet is fixed and the magnetron discharge region 107 is in a fixed state. This cathode 101 has a structure suitable for a target with a small area.

In the example of FIG. 9, the basic structure of cathode 111 is the same as cathode 101 described above. Therefore, in the figure,
Identical elements are given the same reference numerals. The difference is that
A permanent magnet unit 113 is provided with a drive section 112 and a permanent magnet unit 113
14, it is configured to be able to move back and forth. As a result, the magnetron discharge region 107 formed on the upper surface of the target 106 can be moved as shown by the arrow 115, thereby expanding the discharge region. Cathode 111 is suitable for targets with large areas.

In the example of FIG. 10, this cathode 121
is a cathode disclosed in Japanese Utility Model Publication No. 61-42903, in which a large number of electromagnets 122 are arranged at predetermined intervals, and by flowing three-phase alternating current 123 through the electromagnets 122 in a predetermined energization relationship, the upper surface of the target 106 is A magnetron discharge region similar to the above is formed, and the discharge region is moved using the magnetic field generation effect of three-phase alternating current to form a wide discharge region.

[0006]

[Problem to be solved by the invention] Cathode 1 shown in FIG.
In 01, the magnetic field part consisting of magnetic field lines parallel to the surface of the target 106 generates a strong plasma density, and the part of the target corresponding to this part is locally consumed the most, shortening the life of the target and causing the target This has the disadvantage of reducing the utilization efficiency of the system.

In the cathode 111 shown in FIG. 9, the magnetron discharge area is moved by the movement of the permanent magnet unit 113, and the discharge area is expanded and made uniform, thereby solving the above-mentioned problem. However, on the other hand, since a mechanism for moving the permanent magnet unit 113 is provided, there is a drawback that structures such as a mechanism for cooling the cathode and a mechanism for protecting the drive section 112 from high voltage are complicated. Further, if the cathode 106 becomes too large, the permanent magnet unit 113 also becomes large and heavy, and there is also the problem that it becomes difficult to move it with the drive unit 112.

With the cathode 121 shown in FIG. 10, it is possible to generate a discharge over the entire upper surface of the target 106, but it is necessary to sufficiently confine electrons in the outer periphery of the discharge space, especially in the periphery of the target. No consideration was given to this, and as a result, there was a problem in that the efficiency of target use in the outer peripheral area decreased.

In view of the above-mentioned problems, a first object of the present invention is to generate plasma with uniform density over a wide range and to sufficiently confine electrons in the outer periphery of the discharge, thereby applying the method to a sputtering apparatus. In devices, it improves the utilization efficiency of the target, and in devices applied to etching equipment, it creates uniform plasma density over a wide range to improve etching distribution, and in general, it can be configured as a large cathode. Our goal is to provide magnetron cathodes that can be used.

A second object of the present invention is to create a structure in which the discharge area does not change even though the discharge impedance can be changed by changing the magnetic field strength, thereby improving target utilization efficiency and etching distribution. The objective is to provide a magnetron cathode with a constant

[0011]

[Means for Solving the Problems] The magnetron cathode according to the present invention is a cathode that generates a discharge region in the surrounding space by the action of the magnetic field generated by the cathode itself using an internal magnet, and is a cathode that generates a discharge region in the surrounding space by the action of the magnetic field generated by the cathode itself using an internal magnet. a plurality of electromagnets each receiving an alternating current having a relation to each other; and at least a portion of the outer periphery of a region in which these electromagnets are arranged
For example, a pair of magnets are arranged to surround a plurality of electromagnets and create a fixed fixed magnetic field, and in an area inside the constant magnetic field formed by the magnets, the plurality of electromagnets generate the alternating current. The device is characterized in that a magnetic field that moves while being scanned by being supplied with electricity is created, and the moving magnetic field forms the discharge region that moves in response to the magnetic field.

0012

[Operation] The magnetron cathode according to the present invention uses a plurality of electromagnets installed in a predetermined array relationship, and is mechanically driven so that a uniform magnetic field moves while scanning within the plane of the cathode. There is no need to use the section. This makes it possible to increase the size of the cathode and to accommodate high-speed movement. In particular, around the moving magnetic field created by the electromagnet, another magnet that creates a fixed constant magnetic field is placed, and the fixed magnetic field of this magnet is configured to limit the peripheral part of the moving magnetic field.
Electrons in the outer periphery of the discharge area can be confined,
Furthermore, it becomes possible to reduce the overall discharge impedance and achieve stabilization of discharge.

[0013]

Embodiments Below, embodiments of the present invention will be explained based on FIGS. 1 to 7. FIG. 1 is a plan view of a first embodiment of a magnetron cathode according to the present invention, and FIG. 2 is a plan view taken along line II-II in FIG.
3 is a cross-sectional view taken along the line III-III in FIG. 1, FIG. 4 is a diagram showing the moving state of the discharge area in the first embodiment,
FIG. 5 is a plan view of a second embodiment of the magnetron cathode according to the present invention, FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5, and FIG. 7 is a diagram showing the state of movement of the discharge region in the second embodiment.

In FIGS. 1 to 3, reference numeral 1 denotes a cathode having a rectangular parallelepiped shape as a whole, and its planar shape is a rectangle, as shown in FIG. Inside the cathode 1, electromagnets 2 having the same structure are arranged in a line in the longitudinal direction. The electromagnet 2 includes a plate-shaped conductor 2a and a coil winding portion 2b wound around the conductor 2a. The plurality of plate-shaped conductors 2a are arranged parallel to the short sides as shown in FIG. 1, and therefore the plurality of conductors 2a are parallel to each other.
Arranged along the long side. The electromagnets 2 are disposed adjacent to each other in contact with each other while maintaining insulation. The number of electromagnets 2 is a multiple of 3 because this embodiment uses three-phase alternating current for excitation. On a pair of long sides of the cathode 1,
Magnets 3, 3 are provided. These magnets 3, 3 are, for example, permanent magnets and create a stationary, ie fixed, constant magnetic field. The state of the lines of magnetic force of this magnetic field is shown by arrow 4 in FIG. In this embodiment, the magnet 3 is arranged such that the upper end thereof is formed as a N pole and the lower end thereof is formed as an S pole. On the other hand, the electromagnet 2 is excited by passing current through its coil winding 2b, and a three-phase alternating current 5 is used for this power supply. 3 phase AC 5 is R
.
supply to b. A magnetic field is formed in each electromagnet 2 by this three-phase alternating current. An example of the state of the magnetic field is shown by arrow 6 in FIGS. 2 and 3. Since the plurality of electromagnets 2 are excited by three-phase alternating current 5, the phase relationship of the supplied current changes, thereby moving the magnetic field distribution state in the longitudinal direction of the cathode 1 while maintaining the same distribution state. . In the figure, 7 is a yoke for the electromagnet, and 8 is a base on which the magnet 3 is placed.

As described above, the electromagnets 2 arranged in a predetermined positional relationship are sandwiched between a pair of magnets 3 disposed on their long sides. In the upper plane area of cathode 1, 3
Moving magnetic field by electromagnet 2 based on phase alternating current and magnet 3
A fixed magnetic field is combined with the fixed magnetic field, thus forming a composite magnetic field. The combined magnetic field forms a discharge region corresponding to the magnetic field. FIG. 4 shows the discharge region 9 formed on the upper surface of the cathode 1. As shown in FIG. This discharge region 9 moves as shown by an arrow 10 over time as the combined magnetic field moves. In this way, the discharge region 9 can move over the entire upper surface of the cathode 1 and can form an averagely uniform discharge distribution. In the sputtering apparatus, a target is provided in a region in front of the substrate and above the cathode 1 .

[0016] Furthermore, in the cathode 1 having the above configuration,
By changing the intensity of the moving magnetic field formed by the electromagnet 2, the discharge impedance can be changed. In this case, in the case of a sputtering device, etc., the target utilization efficiency does not change. Therefore, it becomes possible to control the discharge impedance independently of the utilization efficiency. That is, the potential of the cathode 1 can be controlled independently.

Next, a second embodiment will be described with reference to FIGS. 5 to 7. This example shows an example of a circular cathode. The basic structure is that the rectangular cathode described in the first embodiment is bent and its short sides are connected and closed. In the drawings, elements that are substantially the same as those described in the previous embodiment are given the same reference numerals. In this cathode 1, twelve electromagnets 2 are arranged in a ring shape. The conductor 2a and the coil winding 2 are arranged so that an annular arrangement is possible.
b has been slightly deformed to correspond to the overall shape. A first magnet 11 is disposed at the center, and a second magnet 12 is disposed around the electromagnet 2 so as to surround it. The magnet 11 is rod-shaped. The arrangement of the magnetic poles of the magnet 11 can be arbitrarily set. The magnet 12 located on the outer periphery is the same as the magnet 3, and has a north pole on the upper end side. When the upper end side of the magnet 11 becomes the N pole,
The discharge region formed in response to the magnetic field is region 13 as shown in FIG. 7(A). On the contrary, S is placed on the upper end side of the magnet 11.
When the pole comes, it becomes a region 14 as shown in FIG. 7(B). Each discharge region 13 or 14 rotates, for example, in the direction shown by an arrow 15 based on the phase relationship of the three-phase alternating current. In this way, the discharge region rotates and the discharge can be generated in a wide range of the cathode 1, and the same effect as in the embodiment described above is exhibited.

Note that in the structure of each of the embodiments described above, a mechanism for varying the distance between the yoke 7 and the base 8 can be provided. This variable structure allows the aforementioned combined magnetic field to be adjusted to an optimal state.

In each of the embodiments described above, the direction of the magnetic pole of the magnet that creates the fixed magnetic field can be set arbitrarily, and the moving direction of the moving magnetic field by the electromagnet can also be changed by changing the energization of the three-phase alternating current. Can be set arbitrarily. Furthermore, the alternating current supplied to the electromagnet is not limited to three-phase alternating current, but a plurality of alternating currents with different phases are sufficient.

[0020]

[Effects of the Invention] According to the present invention, the following effects are achieved. A moving magnetic field is created by supplying, for example, three-phase alternating current to a plurality of electromagnets arranged in a predetermined arrangement relationship, and magnets that create a fixed constant magnetic field are placed around these electromagnets to create a moving magnetic field. Since the moving magnetic field is moved while surrounding the area, discharge can be generated evenly and uniformly in a wide area. Furthermore, even if the discharge impedance is changed by changing the magnetic field strength,
The uniformity of discharge is not impaired and the utilization efficiency is not reduced. Furthermore, it becomes possible to control the discharge impedance independently of the utilization efficiency, and thereby the potential of the cathode can be controlled independently.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a first embodiment of a magnetron cathode according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG. 1;

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a diagram showing the state of movement of the discharge area in the first embodiment.

FIG. 5 is a plan view of a second embodiment of a magnetron cathode according to the present invention.

6 is a sectional view taken along the line VI-VI in FIG. 5. FIG.

FIG. 7 is a diagram illustrating a state of movement of a discharge region in a second embodiment.

FIG. 8 is a longitudinal cross-sectional view of a conventional first cathode.

FIG. 9 is a vertical cross-sectional view of a conventional second cathode.

FIG. 10 is a vertical cross-sectional view of a conventional third cathode.

[Explanation of symbols]

1 Cathode 2 Electromagnet 3 Magnet 5 that creates a fixed constant magnetic field 3-phase AC 7 Yoke 8 Base 9 Discharge area

Claims (1)

[Claims] Claim 1: A magnetron cathode that generates a discharge region in the surrounding space by the action of a magnetic field, comprising a plurality of electromagnets to which alternating current with a predetermined phase relationship is applied to each, and the outer periphery of the region in which these electromagnets are arranged. At least a part of the section includes a magnet that is arranged to surround the electromagnet and generates a fixed constant magnetic field, and in an area inside the constant magnetic field formed by the magnet, a plurality of the electromagnets A magnetron cathode characterized in that a magnetic field that moves while scanning is created by the alternating current, and the moving magnetic field forms the discharge region that moves in response to the magnetic field.