KR20020086026A - Facing Targets Sputtering System for preparation of magnetic multilayer thin film - Google Patents

Abstract

PURPOSE: A facing target sputtering apparatus for fabricating a magnetic multilayer thin film is provided to prevent a damage of a thin film formed on a substrate by changing the position of a substrate. CONSTITUTION: Two targets face to each other. A local discharge phenomenon is generated between a target and a shield ring if a gas such as an Ar gas or an O2 gas is implanted into the inside of a chamber and negative potential of direct current is applied to the targets. Discharge plasma is generated between the targets by catalyzing an ionization process between the targets if an initial discharge is generated after the negative potential of direct current is applied to the targets. The plasma is formed with gamma electrons, negative ions, and positive ions. At this time, the gamma electrons are used for ionizing the implanted gas. A permanent magnet is installed on a backside of the target in order to restrain an impact between the negative ions and the substrate.

Description

Facing Targets Sputtering System for preparation of magnetic multilayer thin film}

In the counter target sputtering apparatus for manufacturing a multilayer thin film, two targets are disposed to face each other. In addition, the permanent magnet is disposed on the back side of the target so that the magnetic field is distributed perpendicular to the target surface. A negative potential is applied to both targets, and a ground potential is applied to the potential of the chamber and the substrate. Therefore, while inducing rotational movement of γ -electrons, one target becomes a reflective electrode of γ -electrons emitted from the opposite target, and γ -electrons reciprocate between two targets. Since the γ -electrons between the targets reciprocate and rotate, the ionization rate of the atmospheric gas is higher than that of other sputtering apparatuses, so that high density plasma can be formed and stable discharge even at a low gas pressure (0.1 mTorr).

The magnetic field generated by the permanent magnets mounted on the back of the two targets is applied in a direction perpendicular to the target surface and not parallel. In other words, if the magnetic field applied from one target is the N pole, the magnetic field generated from the other target is the S pole, so that the target is a high-speed sputter of all materials without being magnetic or non-magnetic.

Both targets can be moved left and right to control the strength of the magnetic field between the targets. In addition, the substrate holder supporting the substrate can also be moved back and forth between the two target centers, thereby changing the position of the substrate.

Since the arrangement of the substrate is in a state spaced apart from the plasma (plasma-free), it is possible to suppress the substrate collision of the particles with the high energy generated during sputtering as much as possible. Thus not only the γ -electrons but also substrate collisions of particles with high energy due to negative ions are completely eliminated. For this reason, not only the problem of damage to the substrate and the deviation of the composition is overcome, but also a film having extremely good crystallinity can be produced.

Having two sets of the target, it is possible to deposit thin films having different characteristics from each other, and having two substrate holders has the characteristic of simultaneously producing a sample having different characteristics or the same characteristics.

In the opposite target sputtering apparatus, a high density plasma can be generated even at a low discharge gas pressure of 0.1 mTorr which is 1 mTorr or less, and a film deposition rate of several thousand kW can be easily achieved for 1 minute. In addition, it has a strong adhesion between the substrate and the thin film, and has a high deposition rate, so it is suitable for mass production of thin films. Accordingly, an object of the present application is to explain that it is possible to deposit a thin film at a higher speed, a lower temperature, and a lower pressure than a conventional device in manufacturing a thin film using a sputtering device, and to explain the superiority of a film obtained due to the structural difference of the sputtering device. In the future, we intend to promote the sputtering technology.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to deposition of a thin film using a sputtering method, and more particularly, to a counter-target sputtering apparatus having a structure in which two targets face each other and a substrate is spaced apart from a plasma.

The conventional magnetron sputtering method has a position of a substrate and an arrangement of permanent magnets on the back of the target. When the target and the substrate face each other and a high voltage is applied to the target and the substrate, a discharge phenomenon occurs and sputtered particles emitted from the target are deposited on the substrate. In this case, the collision of substrates with high energy particles (neutrons, cations, electrons, etc.) can be suppressed to some extent by the permanent magnet on the back of the target, but the particles emitted from the target corresponding to the center of the magnet, that is, the magnetic pole portion, cannot do. Therefore, the substrate surface corresponding to this portion has a locally high temperature, making it difficult to obtain a good film. In addition, γ (a magnetic material target is to form a magnetic path himdeum to form the magnetic field of the target outside) because the generation of the magnetic field by the permanent magnet when the target is a magnetic body is inhibited-high-density plasma, high-speed deposition because it does not bind the electron There is a problem that can not be done. In addition, only one sample can be produced in one experiment.

With the advancement of the thin film manufacturing technology by the sputtering method, the sputtering method has been used in a wide range of fields including the semiconductor industry. However, many problems remain to be solved, such as the realization of high-speed and low-temperature sputtering of ferromagnetic materials and the removal of substrate shocks by negative ions emitted from the target.

An object of the present invention is to solve such a problem, it is possible to suppress the damage of the thin film deposited on the substrate because the position of the substrate does not face the target, high vacuum state (0.1mTorr) for manufacturing a high purity thin film In spite of γ -electron's reciprocating rotational movement, it is the development of sputtering device that can maximize the ionization rate and maintain stable discharge and manufacture multilayer thin film.

The two targets are in opposite positions. Atmospheric gas Ar (or O ₂ ) is injected into the chamber, and a local discharge is formed between the target and the shield ring when a negative (+) potential of direct current is applied to both targets. As described above, when the initial local discharge occurs after the voltage is applied, ionization of the gas injected into the chamber is promoted between the targets, thereby generating a discharge-type plasma between the targets. This plasma consists of gamma -electrons , anions, cations and the like.

At this time, γ -electron plays a major role in ionizing the injection gas. In the case of the opposing target sputtering apparatus, since γ -electrons reciprocally rotate between targets, even when oxygen gas having a lower ionization rate than that of Ar gas is used as the injection gas, it has a higher deposition rate than the conventional sputtering apparatus. Therefore, even in the case of depositing a thin film using oxygen gas, that is, reactive sputtering, a high deposition rate can be regarded as a suitable method for implementing counter production.

Since the anion is the substrate to result in irreparable damage to hit the thin film to be deposited is incident to the substrate in the case of the conventional sputtering method in a position facing the target, γ - on the back of the target in order to suppress the substrate collision of electrons and negative ions Permanent magnets were placed to suppress substrate collision with γ -electrons or anions. In addition, γ -electrons are constrained by the leakage magnetic field formed on the target surface to increase the ionization rate of the atmospheric gas in the vicinity of the target, thereby forming a high density plasma. However, the γ -electrons at the magnetic pole center of the permanent magnet are not trapped by the leakage magnetic field formed on the target surface, but collide with the substrate with a high energy corresponding to the voltage applied to the target. none.

Therefore, in order to solve such a problem, a high density plasma is formed and a thin film is manufactured while the position of the substrate does not face the target. By avoiding the position of the substrate facing the target, it is possible to suppress the damage of the film by maximally suppressing the substrate collision of particles having high energy generated during thin film deposition.

In the case of the conventional magnetron sputtering device, a leakage magnetic field outside the target is not formed, and thus the discharge itself is difficult. However, in the case of the opposite target type sputtering apparatus, even if the magnetic target is used, a high density plasma can be formed to realize a high deposition rate.

With two sets of targets facing each other and two substrate holders, two single-layer and two-layer samples can be simultaneously produced from targets of different characteristics.

As described above, the opposite target type sputtering apparatus has a high deposition rate due to the damage of the thin film deposited due to the substrate collision of the particles with high energy, which has been a problem in the conventional sputtering method, and the difficulty of thin film deposition using the magnetic target. It is expected to make a significant contribution to the field of industry, academia and research that uses thin film deposition using sputtering.

Claims (3)

Place two targets facing each other Permanent magnet on the back of each target (Target 1 is N pole target 2 is S pole) Placement of the substrate spaced from the center between two targets