JPS62127465A - Sputtering device - Google Patents

Abstract

PURPOSE:To prevent the temp. increase of substrate to be treated by the electrons plunging to the substrate by installing similar auxiliary magnets to plasma confining magnets of a magnetron sputtering device so as to face said magnets. CONSTITUTION:A thin film of Al is stuck by an Al target 1 on the surface of the semiconductor substrate 3 with the magnetron sputtering device. An auxiliary plate 6 attached with the auxiliary magnets 5a, 5b made into the same construction as the construction of the plasma confining permanent magnets 2a, 2b provided on the rear side of the Al target 1 is provided to face the magnets 2a, 2b. The distribution of the reflection-imaged magnetic lines 8a of force having the same shape as the shape of the distribution of the magnetic lines 4a of force formed by the magnets 2a, 2b is formed and a magnetical neutral plane 7 having no magnetic fields is formed therebetween. The electrons colliding against the substrate 3 are eliminated by the magnetic lines of force penetrating the substrate 3 and the deterioration of the quality of the vapor deposited Al film on the semiconductor substrate 3 by the local temp. rise of the substrate is prevented.

Description

[Detailed Description of the Invention] [(Already required)] To prevent the lines of magnetic force of the plasma confinement magnet from crossing a substrate, which is a workpiece, by arranging a magnet substantially similar to the plasma confinement magnet to face each other in a sputtering apparatus. This eliminates electrons that move spirally along the lines of magnetic force and rush into the substrate, raising the temperature of the substrate.

[Industrial application field]

The present invention relates to the structure of a magnetron sputtering apparatus for depositing an AI coating onto a semiconductor substrate or the like.

Sputtering devices form thin films using low-pressure gas discharge, and recently magnetron-type devices have been used to increase the film growth rate and are now widely put into practical use.

Magnetron sputtering devices are classified into planar magnetron types, ring magnetron types, and coaxial magnetron types based on the shape of the target.

In both types of magnetron type sputtering equipment, a gas such as a gas is introduced into a vacuum chamber and a glow discharge is performed using DC or RF to turn the gas into plasma, and the target material for the cathode is sputtered onto a substrate placed opposite to the target. When depositing on the target 7), electrons in the plasma are confined by a magnetic field generated by a permanent magnet attached to the back surface of the target 7), thereby promoting the generation of Ar ions, increasing the plasma density and improving the sputtering efficiency.

Therefore, the sputtered target material efficiently reaches the opposing substrate, and a film is formed at high speed.

However, with magnetron sputtering equipment that has a plasma confinement magnet only in one direction of the substrate, even if an anode with the same potential as the substrate is installed or the distance between the substrate and the target is changed, the lines of magnetic force penetrating the substrate can be completely reduced to zero. I can't.

For this reason, electrons that fly around in a spiral manner around the penetrating magnetic field line collide with the substrate, raising the temperature of the substrate and causing the quality of the deposited film to become malt locally. In the case of an AI coating, the temperature difference results in a grain size difference, which manifests as a change in the gloss of the film. Changes in grain size are unfavorable for etching and migration, so improvement is desired.

[Conventional technology]

FIG. 2 is a sectional view schematically showing a conventional planar magnetron type sputtering apparatus.

In the figure, l is a planar AI target to which a negative voltage is applied. In contact with the back surface of this target 1 are the magnetic poles of plasma confinement magnets 2a and 2b made of permanent magnets.

The plasma confinement magnet 2a is a cylindrical north pole, and the plasma confinement magnet 2b is a hollow cylindrical south pole.

A semiconductor substrate 3 is placed above the target 1 at a position facing the target 1 and grounded.

Above the surface of the target 1 is a plasma confinement magnet 2a.
, 2b, and the lines of magnetic force are directed from the north pole to the south pole. 4a is a line of magnetic force that goes from the north pole to the south pole without hitting the substrate 3, and 4b is a line of magnetic force that crosses the substrate 3.

Most of the electrons are confined in the vicinity of the target 1 by the radially closed magnetic lines of force 4a, and do not perform toroidal motion, thereby promoting the generation of Ar ions.

Since the ions are bombarded with a high current density, the rate at which the AI film is formed on the substrate 3 by sputtering is increased. Furthermore, since the plasma is confined in a local space near the target 1, the temperature rise of the substrate 3 is also very small.

However, there are magnetic lines of force penetrating the substrate 3, such as the penetrating magnetic force &i4b, and when the substrate 3 is separated from the target 1, the number of penetrating lines of magnetic force 4b decreases, but does not become completely zero.

[Problem that the invention seeks to solve]

In a conventional magnetron type sputtering apparatus, there are magnetic lines of force that cross the substrate, and electrons that come under the influence of these lines collide with the substrate while moving in a spiral manner, thereby locally increasing the temperature of the substrate. A local temperature rise causes unevenness in the quality of the deposited Al film (mainly unevenness in grain size), which in turn causes bad results in etching and migration.

[Means for solving problems]

The solution to the above problem is to install an auxiliary magnet that forms a magnetic field line distribution similar to that formed by the magnet in a sputtering apparatus equipped with a magnet that forms a closed magnetic field near the target surface, at a position opposite to the magnet. This is achieved by the sputtering apparatus according to the present invention in which the substrate to which the target material is deposited can be placed on the magnetic neutral plane in the intermediate region between the target and the auxiliary magnet or closer to the auxiliary magnet.

[Effect]

In the present invention, auxiliary magnets having the same magnetic field line distribution as the plasma confinement magnet are placed opposite each other to limit the extension of the magnetic field lines from the plasma confinement magnet above the target, and the substrate is placed outside the magnetic field of the plasma confinement magnet. This eliminates any penetration of the substrate by magnetic lines of force caused by the plasma confinement magnet. By doing so, the electrons that fly around the magnetic lines of force are completely eliminated, and the local temperature rise of the substrate is eliminated.

〔Example〕

FIG. 1 is a sectional view schematically showing a planar magnetron type sputtering apparatus with an auxiliary magnet according to the present invention.

In the figure, parts with the same names as in FIG. 2 are indicated by the same symbols.

In the figure, 1 is a planar AI target to which a negative voltage is applied.

In contact with the back surface of this target 1, there are magnetic poles of plasma confinement magnets 2a and 2b made of permanent magnets. The plasma confinement magnet 2a is a cylindrical north pole, and the plasma confinement magnet 2b is a hollow cylindrical south pole.

Auxiliary magnets 5a, 5b having the same structure as the plasma confinement magnets 2a, 2b are installed to face the plasma confinement magnets 2a, 2b. An AI auxiliary plate 6 having the same shape as the target 1 is provided on the lower surface of the auxiliary magnets 5a and 5b, and no potential is applied to this plate.

In this case, the same magnetic field line distribution as that formed by the plasma confinement magnets 2a and 2b can be formed upward in a mirror image manner by the auxiliary magnets 5a and 5b as shown as magnetic field lines 8a. In such a case, a magnetic neutral plane 7 without a magnetic field can be formed at a height midway between both magnets. The substrate 3 is located at this magnetic neutral plane 7 or slightly more than the auxiliary magnet 5a.
, installed near 5b and grounded. When doing this, there are no magnetic lines of force formed by the lower plasma confinement magnets 2a and 2b that penetrate the substrate 3, and therefore no electrons collide with the substrate 3 due to the action of the penetrating lines of magnetic force.
The temperature of the substrate 3 will also no longer rise locally.

Although the target has been described as being AI, it may also be an Al alloy, a high melting point metal, or a silicide thereof.

The auxiliary magnets 5a, 5b and the auxiliary plate 6 may be located either inside or outside the vacuum system.

Further, the auxiliary magnets 5a and 5b are plasma confinement magnets 2a,
As long as it forms approximately the same magnetic force line distribution shape as 2b, the strength may be slightly different.

Further, the magnetic neutral plane can be formed not only in the planar type but also in other types of magnetron type sputtering equipment.

〔Effect of the invention〕

As explained in detail above, according to the sputtering apparatus according to the present invention, there are no electrons impacting the substrate, there is no local temperature rise of the substrate, a film with a uniform grain size can be formed, and etching unevenness can be avoided. Migration etc. can be prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a magnetron type sputtering apparatus with an auxiliary magnet according to the present invention. FIG. 2 is a sectional view of a conventional magnetron type sputtering apparatus. In the figure, 1 is a target, 2a and 2b are plasma confinement magnets, 3 is a substrate, 4a is a magnetic field line, 5a and 5b are auxiliary magnets, 6 is an auxiliary plate, 7 is a magnetic neutral plane, 8a is a magnetic field line plasma 1h Ji M Kuano

Claims (1)

[Claims] In a sputtering apparatus equipped with a magnet that forms a closed magnetic field near the target surface, an auxiliary magnet that forms a magnetic field line distribution similar to the magnetic field line distribution formed by the magnet is installed at a position opposite to the magnet, and the target material is covered with the target material. A sputtering apparatus characterized in that a substrate to be deposited can be placed on a magnetic neutral plane in an intermediate region between a target and an auxiliary magnet or closer to the auxiliary magnet.