KR20080012620A - High uniformity facing target type sputtering apparatus - Google Patents

Abstract

A high uniformity facing target type sputtering apparatus is provided to increase uniformity of a magnetic field in front of a target to improve deposition uniformity of a substrate. A high uniformity facing target type sputtering apparatus comprises targets(6) and magnetic field generators(7) disposed in the rear of the targets. Each magnetic field generator has a recess or a step in the middle of one side thereof. Each magnetic field generator includes permanent magnets composed of a plurality of pieces. The recess or the step(40) has a quadrilateral or semi-circular shape. Each magnetic field generator has a plurality of permanent magnets or a single permanent magnet. The recess or the step has a "C" shape.

Description

Opposite target sputtering device with high uniformity {HIGH UNIFORMITY FACING TARGET TYPE SPUTTERING APPARATUS}

1 is a cross-sectional view of a conventional magnetron sputtering device.

2 is a cross-sectional view of a conventional counter target sputtering apparatus.

3A is a diagram showing an arrangement of permanent magnets used in a conventional counter target sputtering apparatus.

Fig. 3B is a perspective view showing the arrangement of the sputtering target and the permanent magnet in the conventional counter target sputtering apparatus.

3C is a cross-sectional view of a conventional opposing target sputtering apparatus when cut based on the line B of FIG. 3B.

4A is a diagram showing an arrangement of permanent magnets used in the counter-targeted sputtering apparatus of the present invention.

Fig. 4B is a perspective view showing the arrangement of the sputtering target and the permanent magnet in the opposed target sputtering apparatus of the present invention.

4C is a cross-sectional view of the opposing target sputtering apparatus of the present invention when cut based on the line A in FIG. 4B.

5 is a voltage-current characteristic curve of the counter-targeted sputtering apparatus of the present invention.

FIG. 6 is a spectral line of neutral particles and ions of titanium and Ar measured by emission spectroscopy for a conventional magnetron sputtering device and the counter-targeted sputtering device of the present invention. FIG.

7 is a graph showing the deposition rate per minute of the copper thin film deposited by the counter-targeted sputtering apparatus of the present invention.

8 is a graph measuring uniformity of a thin film when a thin film is deposited on a substrate by using a conventional counter target sputtering apparatus and a counter target sputtering apparatus according to the present invention.

* Description of the symbols for the main parts of the drawings *

1: sputter one holder 2: insulator

3: ferrite 4: cathode

5: target holder 6: target

7: field generating means 8: anode

30: substrate support 40: groove

50: power supply a to d: magnet

The present invention implements a high-density, high-ionized plasma by inducing rotational reciprocating motion along the magnetic lines of electrons confined between opposing targets using an opposing sputtering device, and prevents substrate damage due to low temperature deposition and high ion energy. The present invention relates to an opposing target sputtering device that is capable of performing the above, and more particularly, to an opposing sputtering device having a recessed or stepped magnet structure in which a uniform magnetic field is formed on the front surface of the target of the sputtering device to increase the uniformity of thin film deposition on the substrate. will be.

Sputtering is a widely used method in thin film coatings and is used in various industrial fields such as display, optical, abrasion resistant coating, and semiconductor.

Conventional magnetron sputtering techniques are widely used as a technique for forming a film on a substrate using a target facing the substrate surface. 1 shows a conventional magnetron sputtering apparatus. As shown in FIG. 1, a conventional magnetron sputtering device forms a magnetic field for electron and ion confinement in front of a target, and target atoms are sputtered by momentum transfer, for example, when ionized Ar ions collide with the target. However, since the magnetron sputtering technology opposes the target on the substrate surface and the kinetic energy of the sputtered deposition material is excessively high, when the ions having high kinetic energy are sputtered on the polymer or the organic layer of the organic light emitting device, the polymer layer or the organic layer There is a problem that this can be damaged.

Therefore, as one solution to solve this problem, an opposing target sputtering apparatus having a structure that does not directly face the target and the substrate is used.

The opposing target sputtering apparatus according to the prior art has a structure in which a portion of the target except for the opposing target surface is covered with an anode, and a permanent magnet is disposed on the rear surface of the opposing target so as to form a magnetic field perpendicular to the target. It has a structure to constrain it.

A typical counter target sputtering apparatus is shown in FIG. 2. As shown in FIG. 2, a conventional counter sputtering apparatus is composed of an opposing target installed in a vacuum chamber, a permanent magnet installed on a rear surface thereof, a power supply device, and a substrate support for supporting a substrate.

FIG. 3A shows an arrangement of permanent magnets used in a conventional opposing target sputtering apparatus, and FIG. 3B shows an arrangement of a sputtering target and a permanent magnet in a conventional opposing target sputtering apparatus. FIG. 3C shows a cross-sectional view of a conventional counter target sputtering apparatus when cut based on the line B of FIG. 3B, showing each component of the counter target sputtering apparatus and the positions of the targets and the permanent magnets. As shown in FIG. 3, the permanent magnets used in the conventional counter-targeting sputtering device have a rectangular structure and are attached to the target. The opposing target is applied with a negative voltage for sputtered atom and electron emission, the substrate is installed on the side of the opposing target, and the permanent magnet is installed behind the target to apply a magnetic field.

Referring to FIG. 2, when a negative voltage is applied to the opposing sputtering target 6 from the power supply at the same time, the opposing targets 6 are formed by the magnetic field generated by the permanent magnet 7 as a magnetic field generating means. Sputtering plasma is confined in space. In this case, the plasma is composed of gamma electrons, anions, cations, neutral particles, and the like. At this time, the electrons in the plasma maintain a high density plasma while reciprocating by (-) power applied to a pair of sputtering targets while forming a high density plasma while rotating along a magnetic force line connecting opposite sputtering targets. That is, since all electrons or ions in the plasma reciprocate while rotating along the magnetic force line, charged particles with high energy are accelerated to opposite targets and confined in the plasma formed in the space between the targets. Therefore, the high energy charged particles are confined to the target space and are deposited on the substrate located to the side of the opposing target mainly by diffusion of neutral particles having relatively low energy, thereby avoiding damage to the substrate due to high energy particle collision. Thin film formation takes place.

In addition, in the conventional target-type sputtering apparatus according to the prior art, since the substrate surface is located on the side of the opposite target instead of facing the target, the deposition is performed by sputter atoms having relatively low energy deposited, thereby damaging the polymer layer or the organic layer on the substrate. There is an advantage of not letting.

 However, since the uniformity of the magnetic field formed on the front surface of the target is not high in the counter-target sputtering apparatus according to the prior art of this type, there is a problem that the deposition uniformity is not high when the substrate installed on the side of the conventional target is deposited.

The present invention has been made to solve the above problems, to provide a counter-target sputtering device that can increase the uniformity of deposition during deposition of the substrate installed on the side of the target by increasing the uniformity of the magnetic field formed on the front surface of the target It is.

In addition, the present invention has been invented to solve the above problems, an object of the present invention is to implement a high-density plasma, improve the target use efficiency and reduce the kinetic energy of the sputter particles incident on the substrate to prevent thermal damage of the substrate And to provide an opposing sputtering device made to enable high-speed, low-temperature thin film formation.

In order to achieve the above object, the sputtering source of the present invention includes a target and a magnetic field generating means disposed on the target rear surface, the magnetic field generating means is formed in the groove in the inner side or the staircase in the center of the target front surface Improve magnetic field uniformity

In addition, the opposing sputtering apparatus according to the present invention includes a chamber, a pair of targets positioned in the chamber to face each other at a predetermined distance, and having a magnetic field generating means disposed on a rear surface thereof, and a side of the target in the chamber. And a power supply device for supplying electric power to form plasma in the space between the targets and the substrate support for supporting the substrate located in the target, wherein the magnetic field generating means has a groove or a step inwardly formed at the center of the side thereof, so that the front of the target It is characterized by improving the magnetic field uniformity.

The magnetic field generating means of the present invention consists of a permanent magnet formed of several pieces.

In the opposite sputtering apparatus according to the present invention, two targets are disposed to face each other, a permanent magnet is disposed on the rear surface of the target so as to be perpendicular to the target surface, and an equipotential of (-) is applied to the two targets, and the reactor becomes a ground potential. The potential is applied to ground or floating potential.

The magnetic field generated from the permanent magnets on the back of two opposing targets is formed in a direction perpendicular to the target surface, and stable plasma is formed at low pressure (1 mTorr or less) by the high density and high ionization plasma confined between the two targets. By inducing high-speed sputtering and minimizing substrate collision by ions having high energy generated during sputtering, it is possible to prevent substrate damage due to ion bombardment and thermal damage due to radiant heat from a target.

The sputtering apparatus has a feature of depositing binary thin films by mounting targets of different materials. As the film sputter-deposited on the substrate, an oxide including a conductive metal, nitride, organic material, semiconductor, or transparent conductive film (TCO) made of ITO, ZnO, or Me: ZnO may be deposited.

In the target facing sputtering apparatus of the present invention, plasma can be maintained and generated at a lower pressure of 1 mTorr or lower than a conventional magnetron sputtering apparatus by inducing high ionization and high-density plasma. ) Can be induced. Accordingly, an object of the present invention is to produce a thin film by using a sputtering device, a high speed, low pressure, low temperature process is possible than conventional magnetron sputtering, especially low temperature high speed thin film such as organic electroluminescent part of various polymer substrates, organic light emitting display device. It is characterized in that it is applied to a process in which deposition is required. In addition, the greatest feature of the present invention is to form a uniform magnetic field on the target front surface of the sputtering apparatus, which has a target use efficiency (50 to 60%) that is significantly improved than that of a conventional magnetron sputtering apparatus (target efficiency of 5 to 25%). It features.

Hereinafter, an opposing sputtering apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 4A shows an arrangement of permanent magnets used in the counter-targeted sputtering apparatus of the present invention, and FIG. 4B is a perspective view three-dimensionally showing the arrangement of the sputtering target and the permanent magnets in the counter-targeted sputtering apparatus of the present invention. FIG. 4C shows a cross-sectional view of the opposing target sputtering apparatus of the present invention when cut based on the line A of FIG. 4B.

As shown in Fig. 4, the sputtering source of the present invention includes a target 6 and a magnetic field generating means 7 disposed on the rear surface of the target, the magnetic field generating means 7 being recessed inward at the center of the side surface. Or a step is formed to improve the magnetic field uniformity of the front surface of the target.

In addition, the opposing sputtering apparatus according to the present invention includes a pair of targets 6 positioned in the chamber and arranged to face each other at a predetermined distance, and a pair of magnetic field generating means 7 disposed on the rear of each target 6. And a power supply device 50 positioned in the chamber for supporting a substrate and supplying power to form plasma in a space between the target 6 and the magnetic field generating means. (7) is comprised so that grooves or steps may be formed inward in the center of the side to improve the magnetic field uniformity of the target front surface.

The magnetic field generating means 7 may be made of a permanent magnet composed of several pieces. Width and depth of the groove 40 of the magnetic field generating means 7 may be changed depending on the size and position of the target and the power applied. The groove 40 is shaped like a "c", but any other shape is possible, and both rectangular and semicircular shapes are possible. Preferably, the magnetic field generating means 7 is made of a plurality of permanent magnets, but may be made of one permanent magnet.

The opposed target 6 is applied to the cathode for sputtered atom and electron emission, and the substrate is mounted on the side of the opposite target 6 to deposit ions and neutral particles released from the target 6. . The permanent magnet 7 is installed at the rear of the target 6 to apply a magnetic field.

The opposing sputtering device is composed of a target and an anode, which is a cathode composed of a material to be deposited on a substrate, and allows the discharge voltage to be lowered by setting a distance between the anode and the cathode to about 3 mm, and is used in different shapes according to the purpose. .

Fig. 4C shows the relationship between the sputtering source made up of the target and the magnetic field generating means and the other components of the stuttering apparatus in the counter-targeted sputtering apparatus of the present invention. In FIGS. 4B and 4C, the magnet pieces a, b, c and d are shown to help understand the position and shape of the magnetic field generating means in the whole apparatus.

In the opposing sputtering apparatus of the present invention, a power supply used as a deposition source is connected and grounded to an anode and a vacuum chamber, and one target, which is a cathode, and another target are simultaneously connected to form an equipotential, and between the target and the anode. Plasma is generated by the electrical discharge of the to form a hollow cathode (hollow cathode) discharge between the opposing target to increase the plasma density and reactivity and induces good particles on the substrate. The voltage applied to the target 6, which is the cathode, is selectively used among direct current, pulsed direct current, and alternating current.

In the sputtering apparatus of the present invention, the permanent magnets having different polarities are disposed on the rear surface of the opposing target, so that the permanent magnets of the S pole are arranged on one side and the permanent magnets of the N pole on the other side. It is most important to form a uniform magnetic field for improving the use efficiency of the target and generating a uniform plasma. The uniform magnetic field distribution forms a uniform secondary electron density on the front surface of the target to form a uniform plasma.

In the present invention, since the groove 40 is formed in the center surface of the magnetic field generating means made of permanent magnets, the magnetic field generated from the magnetic field generating means 7 on the opposite two target back surfaces is uniform in the direction perpendicular to the target surface. It is formed to improve the magnetic field uniformity of the front surface of the target. Therefore, a stable and uniform plasma is formed between the two targets, thereby forming a uniform thin film on the substrate located on the side of the target.

In addition, the particles confined to the plasma between the opposing targets and incident toward the substrate facilitate the formation of a low temperature thin film without thermal damage of the substrate due to the particles having low kinetic energy being incident.

It is movably mounted to adjust the distance to the opposing target.

5 shows the voltage-current characteristics of the opposed target sputtering apparatus according to the present invention. As the discharge current increases, the discharge voltage also increases linearly. The lower the process pressure, the lower the discharge voltage at the same current value.

6 is a spectroscopic analysis of the spectroscopic analysis of the sputtering apparatus equipped with a titanium target measured by emission spectrometry. In FIG. 6, argon (Ar) neutral particle spectra are located in the 700-800 nm wavelength region, and in the 300-500 nm wavelength region, the spectra of titanium neutral particles, titanium ions, and Ar ions are mainly located. In more detail, Fig. 6A is an emission spectroscopy spectrum measured in a conventional magnetron sputtering apparatus. In the case of the conventional magnetron sputtering device, the emission intensity of Ar ion spectral rays is relatively lower than that of Ar neutral particles, and thus the emission intensity of sputtered titanium neutral particles and ions is also low. 6B shows the emission spectroscopy of the opposed sputtering apparatus of the present invention. In Fig. 5b, the emission intensity of the emission spectra of Ar ions is relatively higher than that of Ar neutral particle spectroscopy, and thus the emission intensity of sputtered titanium neutral particles and titanium ions is also high. Therefore, as shown in FIG. 6, when the same power is applied, the opposing sputtering apparatus of the present invention realizes high plasma density and enables high-speed sputtering.

7 shows the deposition rate of the copper thin film according to the target applied power of the opposing target sputtering apparatus of the present invention. As the target power was increased from 2 kW to 5 kW, the deposition rate per minute was measured from 0.7 μm to 1.8 μm.

FIG. 8 is a graph measuring uniformity of a thin film when a thin film is deposited on a substrate by using a conventional counter target sputtering apparatus and a counter target sputtering apparatus according to the present invention. FIG. 8A illustrates a conventional counter target sputtering apparatus. Data when a thin film is deposited on a substrate, and FIG. 8B is data when a thin film is deposited on a substrate using a conventional counter target sputtering apparatus.

As shown in FIG. 8A, when the thin film is deposited on the substrate by using a conventional counter target sputtering apparatus, it can be seen that the deposition thickness becomes thinner as the distance from the center of the substrate decreases, and such a change in thickness changes rapidly. It can be seen that. In contrast, as shown in Figure 8b, it can be seen that the target sputtering apparatus according to the present invention is a thin film is deposited with a uniform thickness over a large area of the substrate.

What has been described above has described one embodiment according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, without departing from the gist of the present invention, the field to which the present invention pertains. It will be said that the scope of the present invention to the extent that those skilled in the art can change.

As described above, the present invention increases the uniformity of the magnetic field formed on the front surface of the target, thereby increasing the uniformity of deposition during deposition of the substrate provided on the opposite target side.

In addition, the present invention implements a high-density plasma, improves the target use efficiency, and reduces the kinetic energy of the sputter particles incident on the substrate to prevent thermal damage of the substrate and to form a high speed and low temperature thin film.

The present invention enables high-speed deposition and low-temperature deposition without damaging the substrate, and thus thin film deposition without damaging the organic light emitting layer of the polymer substrate and the organic EL device is possible.

Claims (11)

And a magnetic field generating means disposed on the rear surface of the target, wherein the magnetic field generating means has a groove or a step formed inward at the center of the side to improve the magnetic field uniformity of the front surface of the target. The sputtering source of claim 1, wherein the magnetic field generating means is a permanent magnet composed of a plurality of pieces. The sputtering source according to claim 1, wherein the recess or step shape is rectangular or semicircular. The sputtering source according to claim 1, wherein the magnetic field generating means may consist of a plurality of permanent magnets or one permanent magnet. The sputtering source according to claim 1, wherein the groove or the step is shaped like a "c". A substrate support for supporting a chamber, a pair of targets disposed in the chamber and facing each other at a predetermined distance, and having a magnetic field generating means disposed on a rear surface thereof, and a substrate located on the side of the target in the chamber; And a power supply device for supplying power to form a plasma in the space between the targets, wherein the magnetic field generating means is provided with grooves or steps formed inward at the center of the side to improve the magnetic field uniformity of the front surface of the target. Sputtering device. 7. The opposed sputtering apparatus according to claim 6, wherein the magnetic field generating means is a permanent magnet composed of a plurality of pieces. 7. The opposed sputtering apparatus according to claim 6, wherein the groove is rectangular or semicircular. 7. The opposed sputtering apparatus according to claim 6, wherein the magnetic field generating means may consist of a plurality of permanent magnets or one permanent magnet. 7. The opposed sputtering apparatus of claim 6, wherein a permanent magnet having a different polarity is disposed on the rear surface of the target. 7. The opposed sputtering apparatus according to claim 6, wherein the groove or the step is shaped like a "c".

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