JPH0881769A - Sputtering device - Google Patents

Abstract

PURPOSE: To prevent the nonuniform erosion of a target and improve the use efficiency thereof by constituting a magnetron sputtering device in such a manner that the positions of orthogonal electromagnetic spaces on the target are made movable by operation from outside and that the operation is automated. CONSTITUTION: Electromagnet groups 4, 5 formed by arranging plural electromagnets 3 in series are arranged in plural columns to arc shapes drawing concentrical circles on the same plane around a permanent magnet 1 to form magnetic field constituting parts. Further, the changeover of the excitation wirings to these electromagnet groups 4, 5 and the adjustment of current values are made freely selectable. The movement of the central position of the orthogonal electromagnetic spaces toward the outer side according to an increase in the current value is made possible by successively changing over the excitation to the second electromagnet group 5 on the side outer than the first electromagnet group 4 on the central side. Then, the operation is automated and inverted by the programming operation, by which the distributions of the orthogonal electromagnetic spaces are equaled and the erosion of the target is made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus in which the amount of target consumption is equalized. The vacuum deposition method and the sputtering method are known as means for forming a thin film on a substrate, and both are commonly used.The former is a method of melting and thermally evaporating a thin film forming material in a vacuum. In contrast to the former method, the latter is a method in which an inert gas ion [mainly argon ion (Ar ⁺ )] accelerated by an electric field collides with a thin film forming material (target) and is ejected by the impact. Since it has higher kinetic energy than that of the target, it has a strong adhesive force and can form a film having the same composition as the target. It can be used to form wirings and electrodes of semiconductor elements, wirings of liquid crystal display elements and transparent conductive films. It is widely used for the formation of

[0002]

2. Description of the Related Art The original sputtering system employs a bipolar system that uses direct current or 13.56 MHz high frequency discharge as a power source. Since the glow discharge is used, the ion current density at the target surface is low, and therefore the vacuum There is a problem that the growth rate of the thin film is slower than vapor deposition.

Therefore, as one of the methods for improving the growth rate, a magnetron sputtering method utilizing magnetron discharge has been developed and generally used. In this method, a permanent magnet is provided on the back surface of the target to generate a closed annular magnetic field in the space near the target surface. The target is originally connected to the cathode of the power supply and a vertical electric field is applied. Therefore, an orthogonal electromagnetic space arises, and therefore electrons are trochoidal in this space.
(Trochoidal) It is confined by motion and repeatedly collides with Ar gas to become Ar ⁺ , so that the ion current density can be increased as a result of densifying the plasma, and by increasing this power, thin film growth The speed has dramatically improved and it has come to be used in mass production processes of semiconductor devices and liquid crystal display devices.

FIG. 3 is a perspective view showing a conventional magnetic field applying structure, which is composed of a pair of permanent magnets 1 and 2 made of barium (Ba) ferrite, KS Alnico, etc. Is attached to the back surface of the target and is configured to cool the target by adopting a water cooling structure.

Then, the magnetic field lines emitted from N _{1 of the} permanent magnet 1 go to S _{2 of the} permanent magnet 2 arranged concentrically, and N
Results horizontal component upon returning from ₂ to S ₁ of the permanent magnet 1 is orthogonal to the electric field lines between the anode over the cathode is the orthogonal electromagnetic space is to cause electrons trochoidal motion occurs.

However, the problem of this magnetron sputtering is that the target is not efficiently used and the target is unevenly eroded because the position of the orthogonal electromagnetic space on the target is fixed.

As measures against this, measures such as increasing the thickness of a portion where the target has a large amount of erosion (hereinafter referred to as erosion) or moving the position of the permanent magnet have been taken. Has not been obtained.

[0008]

In magnetron sputtering, since the position of the orthogonal electromagnetic space on the target is fixed, the target is unevenly eroded and the use efficiency is poor. Therefore, it is an object to put the device configuration in which the use efficiency of the target is improved into practical use.

[0009]

SUMMARY OF THE INVENTION The above-mentioned problem is that the magnetic field forming section of the device has an arcuate electromagnet group in which a plurality of series-connected electromagnets are concentrically arranged on the same plane centering on a permanent magnet. Can be realized by selectively switching the wiring to the electromagnet group and adjusting the current value.

[0010]

In the present invention, the position of the orthogonal electromagnetic space on the target can be changed by an operation from the outside.
By automating the programming operation, the erosion of the target can be made uniform and the use efficiency can be improved.

That is, in the conventional method of mechanically moving the position of the permanent magnet, since the position is displaced from the center position of the target, the spatter distribution is likely to be non-uniform, and the moving mechanism is complicated, and good results are obtained. I can't.

On the other hand, according to the present invention, the position of the magnetic field lines is changed while the position of the magnet is fixed. Since the operation is performed electrically, the position of the orthogonal electromagnetic space can be changed smoothly.

FIG. 1A is a perspective view showing a magnetic field applying structure according to the present invention.
There is a plurality of electromagnet groups in which concentric circles of electromagnets 3 each having a minute unit as shown in FIG.

This figure shows the case of the first electromagnet group 4 and the second electromagnet group 5, but the present invention changes the strength of the exciting current to the electromagnet group, and The position of the orthogonal electromagnetic space is smoothly changed by switching the exciting current.

FIG. 2 is a schematic cross-sectional view showing the center position of the orthogonal electromagnetic space and corresponds to the schematic cross-sectional view of FIG. 1, and the upper surface of the magnetic field applying mechanism including the permanent magnet 1 and the electromagnet groups 4 and 5 is It is in contact with the target 6 and the lower surface is lined with a magnetic plate 7 to form a magnetic circuit.

Here, when the first electromagnet group 4 and the second electromagnet group 5 are not energized and only the permanent magnet 1 works, the magnetic pole N
_Since the magnetic force line 8 extending from ₁ returns to the magnetic pole S ₁ through the shortest distance, the center position of the orthogonal electromagnetic space is at the position of a in the vicinity of the permanent magnet 1.

Next, when the exciting coil of the first electromagnet group 4 is energized, the magnetic force line 10 emitted from the N ₂ pole of the first electromagnet group 4 is added to the magnetic force line 8, so that the size of the orthogonal electromagnetic space increases and the As the magnitude of the exciting current to the electromagnet group 4 of No. 1 increases, the center position of the orthogonal electromagnetic space shifts to the position b.

Next, when the exciting coil of the second electromagnet group 5 is energized in this state, the magnetic force lines 11 of the second electromagnet group 5 are added to the magnetic force lines passing through the permanent magnet 1, and the size of the orthogonal electromagnetic space is further increased. In addition, as the magnitude of the exciting current to the electromagnet group 5 increases, the center position of the orthogonal electromagnetic space shifts to the position c.

By sequentially switching to a plurality of electromagnet groups in this way, it is possible to shift the center position of the orthogonal electromagnetic space to the outside, and by repeating this operation automatically, the distribution of the orthogonal electromagnetic space is made uniform. Can be
Therefore, the erosion of the target can be made uniform.

[0020]

[Embodiment] In the magnetic field applying structure shown in FIG. 1, as the unit electromagnet 3, a coil having 300 turns is wound around a ferrite magnetic core having a length and a width of 2 cm and a height of 5 cm. A first electromagnet group 4 and a second electromagnet group 5 were formed by connecting to the circuit to and were arranged concentrically around the permanent magnet 1.

Here, the magnetic flux density of the permanent magnet 1 is 800 gauss, and the first electromagnet group 4 and the second electromagnet group 5 are
The output can be adjusted in the range of 0 to 1 K gauss by adjusting the exciting current.

First, the state where the switches to the electromagnet groups 4 and 5 are turned off is set to the starting state, and then the switch to the first electromagnet group 4 is turned on until the magnetic flux density reaches 600 gauss. , The exciting current is gradually increased.

When the magnetic flux density reaches 600 gausses, the switch of the second electromagnet group 5 is further turned on, and the exciting current is gradually increased until the magnetic flux density reaches 600 gausses.

When the magnetic flux density reaches 600 gausses, the switches of the first electromagnet group 4 and the second electromagnet group 5 are turned off so that only the permanent magnet 1 has a magnetic field. By repeatedly applying such a magnetic field, the center position of the orthogonal electromagnetic space can be moved concentrically right above the target in a constant cycle, and thus the erosion of the target can be equalized.

[0025]

[Effects of the Invention] The use efficiency of the target can be improved by implementing the present invention.

[Brief description of drawings]

FIG. 1 is a perspective view showing a magnetic field applying structure according to the present invention.

FIG. 2 is a schematic sectional view illustrating a center position of an orthogonal electromagnetic space.

FIG. 3 is a perspective view showing a conventional magnetic field applying structure.

[Explanation of symbols]

 1, 2 permanent magnets 3 unit electromagnets 4 first electromagnet group 5 second electromagnet group 6 target 7 magnetic plate 8, 10, 11 magnetic field lines

Claims (1)

[Claims] 1. In a sputtering apparatus for performing magnetron sputtering, a magnetic field forming section of the apparatus has an arc-shaped electromagnet in which a plurality of series-connected electromagnets are concentrically arranged on the same plane with a permanent magnet as a center. Form a group,
A sputtering apparatus, which is formed so as to selectively switch wiring to the electromagnet group and adjust a current value.