JPH03150355A - Sputtering device - Google Patents

Abstract

PURPOSE:To improve the efficiency of utilizing a target without deteriorating the uniformity of the thickness of the deposited film on a substrate with the sputtering device by disposing plural electromagnets in the specific position between a substrate to be treated and a target supporting electrode. CONSTITUTION:A shutter plate 4 and the target 6 are disposed to face the substrate 3 on a substrate supporting base 2 in a vacuum chamber 1 and gaseous Ar is introduced into the chamber. Glow discharge is generated between the substrate 3 as an anode and a cathode 8 on the rear surface of the target to generate plasma to ionize the gaseous Ar and to sputter the target 6. The thin film consisting of the target material is then formed on the substrate 3 by opening the shutter plate 4. Two sets of the electromagnets 5a to 5d and 5A to 5D are installed within the two planes so as to enclose the electric field within the plane perpendicular to the electric field formed by the substrate 3 and the cathode 8 in this case. The easy control of the magnetic fields from the target surface by the intensity of the currents to be passed to the electromagnets, the combination of frequencies, etc., is possible and the control of the distribution of the Ar ions is facilitated. The efficiency of utilizing the target is thus improved without deteriorating the uniformity of the thickness of the deposited film consisting of the target material on the substrate 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sputtering device, and particularly to a sputtering device for controlling secondary electrons and inert gas ions (charged particles) generated in the dark part of a cathode using a magnetic field. Regarding the structure of magnets.

[Conventional technology]

A conventional sputtering apparatus will be explained using drawings.

FIG. 3 is a cross-sectional view of an example of a conventional sputtering apparatus.

A substrate 3 is provided on a substrate support stand 2 in a vacuum chamber 1, and a shutter plate 4 and a target 6 are arranged opposite to this substrate 3. This shutter plate 4 is used to control the thickness of the film emitted from the target and the film deposited on the substrate 3, and when sputtering onto the substrate 3, it is moved from the space between the substrate and the target. It will be done. Further, the target 6 is placed on the cathode 8. Degree of vacuum 10-” to 2×10-nmH where glow discharge occurs
After Ar gas is introduced into the vacuum chamber l up to g, the substrate 3
A high DC voltage is applied between the electrode 8 and the cathode 8.

Near the target and Toro, there is a cathode dark area (
Crookes Dark Space) is generated, and electrons are accelerated from the target 6 toward the substrate 3 and have high energy. The high-energy electrons collide with Ar atoms in the vacuum chamber 1, and the ionized Ar collides with the target 6 due to the electric field, releases the target constituent elements, and further generates secondary electrons. let

In this type of sputter song device, the edge effect (edge effect) in which the thickness of the sputter song film formed around the substrate 3 is thin due to the finite edge radius.
Loss), and since the discharge becomes stronger around the cathode 80, more atoms are splattered around the target 6, and the thickness of the sputtered film becomes thinner at the center of the substrate 3. Although they exhibit opposite characteristics, they do not exactly cancel each other out.

Therefore, in the conventional sputtering apparatus, as shown in FIGS. 4(a) and 4(b), the cathode 8 has a magnetic field component parallel to the surface of the target 6, and the target 6 and
A rotating body 9 with a permanent magnet 10 that rotates independently of the cathode 8 is installed, and measures are taken to improve the uniformity of the film sputtered onto the substrate 3. Further, the side surface of the target 6 is covered with a protection plate 7. The typical reduction situation of target 6 at this time is shown in Figure 4(b).
The result will be as shown in .

[Problem to be solved by the invention]

In the conventional sputtering apparatus described above, the substrate 3
In order to make the thickness of the sputter song film deposited on the film uniform, a permanent magnet 10 is placed on a rotating body 9, and the permanent magnet 10 is rotated about a support rod 11 as a rotation axis. The state of the magnetic field at this time will be explained using FIGS. 3 and 5.

First, the y-axis is taken in the direction of the magnetic field within the plane of the target 6, and the x-axis is taken in the direction perpendicular to it (in the same plane). Two axes are taken in the direction of the substrate 3 perpendicular to these two axes. At this time, the magnetic field B generated by the permanent magnet IO is a function of 2 B (
Z).

The direction of the magnetic field B in which the charged particles move is only inertial, and the motion is conserved. For the XZ direction, the electric field E (
Z) (occurs between substrate 3 and cathode 8),
When the charge of a charged particle is q, the mass is M, and the initial velocity is V,
Perform speed parallel to the X direction.

Assuming that this magnetic field rotates in the x, y plane, the charged particle receives force in two directions due to the electric field E (Z), and
Cycloidal motion will be performed in the y-plane.

However, as described above, in the conventional sputtering apparatus, the permanent magnet 1O is attached to the lower part of the target 6, so the magnetic field B (Z) cannot be freely adjusted. For this reason, it is difficult to widen the area where the target is reduced without deteriorating the uniformity of the deposited film on the substrate, and the target utilization efficiency is also low. The negative effect of high-energy electrons on the substrate was also a major problem.

Recently, there has been an increasing demand for sputtering substrates with different diameters using a single device, but in such cases, conventional devices require only one shield plate 4. In addition to replacing target 6 etc.
It was essential to replace and adjust the permanent magnet IO.

Furthermore, since the rotation of the magnetic field is the rotation of the permanent magnet itself, there is a problem in that mechanical failure is likely to occur.

[Means to solve the problem]

The sputtering apparatus of the present invention includes a substrate support for supporting a substrate, and a cathode (or high-frequency electrode) provided opposite to the substrate support for installing a target. perpendicular to the electric field created by the substrate and the cathode (
A plurality of electromagnets having magnetic field components are provided in at least two planes between the electromagnets (or high-frequency electrodes).

〔Example〕

Next, the present invention will be explained using the drawings.

Fig. 1 is a cross section of an embodiment of the present invention, Fig. 2(a),
(b) is a top view and a sectional view taken along the line X-X in the vicinity of the target.

A shutter plate 4 and a target 6 are arranged on a substrate support stand 2 in a vacuum chamber 1, facing a substrate 3. In the conventional device, a permanent magnet 10 is attached to a rotating body 9 inside a cathode 8 to generate a magnetic field from below the target 6. However, in this embodiment, a magnetic field is generated from below the target 6.
There is no permanent magnet under the target, and the secondary electrons and Ar ions (charged particles) generated near the target are controlled by an arrangement that surrounds the electric field in a plane perpendicular to the electric field created by the substrate 3 and the cathode 8. Two sets of electromagnets 5a to 5d and 5A
~Performed by 5D. The distance between the planes of the substrate 3 and the cathode 8 is d = 10-''m, the magnetic field B generated by the electromagnets 5A to 5D is 10-2W b / m, and the frequency of the rotating magnetic field is f = 2.8-10''Hz. Electromagnet 5A~
Control the current of 5D.

At this time, the electrons that entered the magnetic field B vertically above the target end at a velocity V e = 105 m/5ec
The condition that V(2)T≦− does not occur outside the parallel electric field formed by the target cathode within the time required for the reversal of the target cathode. Here D is the diameter of the target.

When D=15X10-m, solving this gives the following.

Therefore, the magnetic fields created by the electromagnets 5a to 5d are the electromagnets 5A to 5d.
For the magnetic field created by 5D, △B=7.2・IO−(W
The change must be within the range of b/n(). By doing this, the electrons (V e =
10 m/sec), the electric field can be maintained even above IX10 m, and the electron distribution can be made uniform. Furthermore, since electrons have cycloidal motion, they can efficiently exchange energy with Ar. Since high-energy electrons can be uniformly distributed on the target, the target material can be sputtered uniformly, and the target 6 shown in FIG. 2(b) can be effectively used.

Note that the number of electromagnets in one plane can be greater than four. By increasing the number, the magnetic field strength can be increased.

Furthermore, this embodiment can be used in combination with the conventional magnetic field generation mechanism shown in FIG. 3, making it easier to confine charged particles. Furthermore, the third magnetic field is applied to the electromagnet 5a.
By attaching it closer to the substrate than the plane formed by ~5d and adjusting the rate of change of the magnetic field, all the electrons that collide with the substrate can be swept out of the electric field created by the target and the cathode t=lie. This third magnetic field causes the plane of the substrate 3 and the electromagnets 5a to 5 to
It becomes possible to eliminate damage to the substrate due to high-energy electrons existing between the planes formed by d.

In addition, although the case where a cathode was used was explained in the said Example, a high frequency electrode may be sufficient.

〔Effect of the invention〕

As explained above, the present invention has the advantage of attaching a plurality of electromagnets each having a magnetic field component perpendicular to the electric field created by the substrate and the cathode and in two or more planes between the substrate and the cathode. The magnetic field as a function can be easily controlled by combining the strength and frequency of the current flowing to the electromagnet, making it possible to control the distribution of electrons and, in turn, the distribution of Ar ions, resulting in uniform thickness of the deposited film on the substrate. Target usage efficiency can be increased without deteriorating performance.

This makes it possible to avoid collision of high-energy electrons with the substrate, reducing substrate damage. Furthermore, the rotation of the magnetic field is
It does not include mechanical rotation because it can be done electrically. For this reason, failures can be reduced. Furthermore, when sputtering is required for substrates with different diameters, the conditions can be easily optimized by combining the strength and frequency of the current flowing to the electromagnet.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of one embodiment of the present invention, and Figure 2 is (a).
(b) A top view and a cross-sectional view taken along the line X--X in the vicinity of the target, FIG. 3 is a cross-sectional view of the conventional example, and FIG. 4(a). Cb) is a top view and a sectional view taken along the Y-Y line of the conventional example near the target, and FIG. 5 is a diagram showing the movement of charged particles in a magnetic field. l...Vacuum chamber, 2...Substrate support stand, 3
... board, 4-...sha, tar board, 5&
~5d, 5A~5D... Electromagnet, 6...
・Target, 7...Protection plate, 8...
Cathode, 9... Rotating body, lO... Permanent magnet, 11... Support rod. Agent Patent Attorney Uchihara Oto 3

Claims (1)

[Claims] In a sputtering apparatus having a substrate support stand that supports a substrate and a cathode (or high frequency electrode) provided opposite to the substrate support stand and on which a target is placed, an electric field created by the substrate and the cathode (or high frequency electrode) is used. A sputtering apparatus characterized in that a plurality of electromagnets having magnetic field components are provided vertically and in at least two planes between the substrate and the cathode (or high-frequency electrode).