JPS63109163A - Sputtering device - Google Patents

Abstract

PURPOSE:To form a thin film of target substance which is homogeneous and has uniform thickness on a circular base plate at high velocity by making a permanent magnet provided on the rear surface of the target to the specified shape and also making it rotatable in a magnetron sputtering device. CONSTITUTION:In the inside of a vacuum tank 2, a circular base plate 8 is fitted to an anode 6 and also a discoid target 10 is similarly arranged as a cathode to the opposite position and a rotary table 20 rotated with a motor 18 is provided on the rear surface of the target 10. A permanent magnet 16 is provided on the rotary table 20 so that one magnetic pole 22 is positioned on the central position of the rotary table 20 and the other magnetic pole 24 is made to a magnet having a circular arc-like shape reaching the outer peripheral edge part of the rotary table 20. Gaseous Ar is introduced into the vacuum tank 2 and DC high voltage is impressed between the target 10 as the cathode and the anode 6 to discharge plasma and a thin film is formed on the base plate 8 by ionizing Ar and sputtering the target 10. In this case, since the permanent magnet 16 is rotated together with the rotary table 20, the thin film of the target substance which is homogeneous and has uniform thickness can be formed on the base plate 8.

Description

TECHNICAL FIELD The present invention relates to a sputtering apparatus, and more particularly to a magnetron sputtering apparatus that can advantageously form a thin film layer with excellent properties on a predetermined circular substrate.

(Prior art and its problems) In recent years, a sputtering chamber is maintained under a high reduced pressure (vacuum) and a discharge gas is introduced into the sputtering chamber, in which a target and a substrate are placed facing each other. A sputtering technique is useful in which atoms sputtered from the target are deposited on the substrate by forming a discharge space between the target and the substrate to form a predetermined thin film on the surface of the substrate. As one of the most effective film-forming methods, it has received attention in various technical fields such as electronic parts, optical parts, magnetic parts, vehicle parts, and decorative products, and efforts are being made to put it into practical use. Depending on the application of the film-formed product, various characteristics are required of the thin film formed on the substrate, and there is also a demand for the development of a sputtering apparatus that can form a thin film with such characteristics.

For example, in a magnetic disk formed by forming a magnetic thin film on a circular substrate, the thin film must be uniform and homogeneous, and sputtering is used to increase the coercive force in the circumferential direction. It is required to control the crystal orientation of the thin film being deposited, and therefore sputtering equipment requires
It must be possible to form a magnetic thin film with such characteristics, and also to generate as little dust as possible that would affect the quality of the formed magnetic thin film, and to have a high N productivity. They are required to be superior and have a simple structure.

By the way, as sputtering apparatuses for forming magnetic thin films (medium layers) of the above-mentioned disks, etc., the following two types have been developed.

First, in one type of device, a tray type (also called a passing type), a tray carrying a large number of substrates is passed over the target, and as it passes, each substrate is It is said to be a device for mass production in which the atoms sputtered from the target are deposited on the target, but the direction of crystal orientation of the thin film formed by such sputtering operation is not linear in the direction of tray passage. Therefore, in the case of a magnetic disk or the like where the shape of the substrate on which the film is formed is circular, there is a problem that the direction of crystal orientation of such a thin film is not in the circumferential direction. In other words, in a circular magnetic disk, the coercive force of the magnetic thin film formed by sputtering is large in the direction equal to the tray passing direction. It increases and decreases at a cycle of 180° in the circumferential direction, and furthermore, this variation in the magnetic characteristics in the circumferential direction results in a variation in the reproduced output signal, which is one of the causes of modulation errors.

However, in order to eliminate modulation caused by variations in magnetic properties (due to film orientation), it is conceivable to perform sputtering while rotating the substrate on which the film is to be deposited; Due to the generation of dust due to the presence of mating parts and the complexity of the equipment, it has not been put into practical use, and currently, it is used as a stationary facing type equipment, which is another type of sputtering equipment.
The only equipment that has been developed is one in which the circular substrates to be subjected to film formation are opposed to each other with their centers aligned above a circular cuget, and sputtering is performed in a stationary state. However, even with this method, the plasma generated by the discharge swells in the radial direction of the target and becomes larger, so the crystal orientation of the deposited thin film becomes radial. The problem is that the magnetic force is larger in the radial direction than in the circumferential direction.

(Solution Means) Here, the present invention has been made against the background of the above, and its feature is that a target and a circular substrate are placed in a sputtering chamber under reduced pressure in which a discharge gas exists. Atoms sputtered from the target are deposited on the circular substrate by arranging them facing each other and forming a discharge space between them to generate a discharge, thereby forming a predetermined thin film on the surface of the substrate. In the sputtering apparatus, a magnet means for forming a strong sputtering region of a predetermined width extending in the radial direction on the target portion corresponding to the circular substrate is provided outside the sputtering chamber and behind the target. and rotary drive means for rotating the magnet means about the center of the circular substrate, and the rotation of the magnet means by the rotation drive means causes the strong sputtering region to be located on the circular substrate. In the sputtering apparatus, the sputtering atoms are deposited mainly in the circumferential direction of the circular substrate by moving the sputtering atoms in the circumferential direction.

(Function/Effect) By the way, in order to improve the film formation rate by sputtering, a magnet is placed on the back side of the target so that some of the lines of magnetic force generated between the two magnetic poles become parallel to the surface of the target. The technique in which a magnetic field tunnel is formed on the target in this way is well known as magnetron sputtering.

In this magnetron sputtering technology, the secondary electrons emitted from the target are captured in the tunnel of the magnetic field formed on the surface of the target by the magnetic field formed by the magnet, and the gas (discharge gas) Because the number of collisions with molecules increases, more ions are generated than in the absence of such a magnetic field, and the area becomes more sputtered. It is possible to raise the target.

The present invention provides magnet means provided behind the target in such a magnetron sputtering apparatus in order to increase the film formation rate, with a predetermined width in the radial direction corresponding to the circular substrate on which the film is to be formed. By rotating such magnet means in the circumferential direction of the circular substrate, the sputtered material is The sputtered atoms are made to move in the circumferential direction of the sputtering target, and by utilizing the non-uniform sputtering condition in which the sputtering position is moved in the circumferential direction, It is attached (deposited) to the circular substrate at a high incident angle in the circumferential direction.

Therefore, by rotating the magnet means that generates a non-uniform magnetic field circumferentially on the target and gives a difference in sputtering speed within the target in the circumferential direction, the magnet means is rotated along the circumferential direction of the circular substrate. , the thickness distribution of the thin film formed on such a circular substrate in the circumferential direction can be effectively suppressed, resulting in a uniform and homogeneous thin film, and the crystal orientation of such a thin film can be controlled in the circumferential direction. This made it possible to effectively eliminate modulation.

In addition, since the sputtered atoms ejected from the target are deposited on the opposing circular substrate at a high incident angle, forming a uniform thin film, a C0-Ni medium film is used as a magnetic thin film in a magnetic disk. When a film is formed, the coercive force in the circumferential direction of the disk can be effectively increased.

Furthermore, in the sputtering apparatus according to the present invention, compared to the case where a circular substrate is rotated within the sputtering chamber (vacuum chamber), since there is no rotation mechanism (rubbing part) within the sputtering chamber, dust is generated. The present invention has the characteristics that the occurrence of such problems can be suppressed to a minimum due to the transport of the substrate, and the structure is also simple.

Note that the magnet means in the sputtering apparatus according to the present invention generally has one of its two magnetic poles (S pole and N pole) located at a position corresponding to the center of the circular substrate, and the other one located at a position corresponding to the center of the circular substrate. In addition to the structure in which the two magnetic poles are arranged in an arc shape of a predetermined length at a position corresponding to the peripheral edge of the circular substrate, the two magnetic poles are arranged facing each other so as to extend in the radial direction of the circular substrate with a predetermined distance apart. This structure is advantageously adopted, and in particular, by adopting the magnet means of the latter structure, it is possible to increase the utilization efficiency of the target portion corresponding to the radial direction of the circular substrate. This has the advantage of improving the utilization efficiency of the entire target.

(Specific Configuration/Examples) Hereinafter, the configuration of the present invention will be described in more concrete detail based on the examples shown in the drawings.

First, FIG. 1 conceptually shows an example of a sputtering apparatus according to the present invention, in which 2 is:
This is a sputtering chamber (vacuum chamber) that can be sealed. This sputtering chamber 2 is connected to a vacuum pump (not shown),
While the inside of the room can be maintained under a high reduced pressure (high vacuum) of about 10-3 Pa or less, an inert gas such as argon (Ar) is introduced into the room through the gas introduction vibrator 4. The interior of the sputtering chamber 2 can be adjusted to create an atmosphere under a predetermined reduced pressure, for example, about 1 to 10 Pa, in which the discharge gas is present.

Further, in the sputtering chamber 2, an anode 6 having a structure similar to the conventional one is provided, and a circular substrate 8 to be deposited, for example, a magnetic disk substrate, is placed on the anode 6. A target 10 as a cathode made of a material to be sputtered is provided concentrically facing the circular substrate 8 and at a predetermined distance away from the circular substrate 8 so as to constitute a part of the partition wall of the sputtering chamber 2. A discharge space 1 is located between this target 10 and the circular substrate 8.
It is said to be 2.

Note that here, an external DC power source 14 is connected between the circular substrate 8 and the target 10 so that so-called DC bipolar sputtering can be performed. It is also possible to configure the device so that high frequency sputtering can be performed using a known high frequency power supply.

Behind the target 10 and outside the sputtering chamber 2, a permanent magnet 16 is placed on a rotary table 20 rotated by a motor 18. It is placed so that it can be rotated about the center of the circular substrate 8. That is, as shown in FIGS. 2 and 3, the center of rotation of the rotary table 20 is positioned on the center of the circular substrate 8 and the target 10, which are arranged concentrically opposite each other. One magnetic pole of the permanent magnet 16 (ζ iron is S
The poles 22) are arranged. On the other hand, the other magnetic pole (here, the N pole 24) of the permanent magnet 16 is located at the outer peripheral edge of the rotary table 20, and extends in an arc shape with a predetermined length to a position corresponding to the peripheral edge of the circular substrate 8. It is structured as a shape.

Therefore, in a device having such a structure, while electric discharge is performed between the circular substrate 8 and the target 10 according to a conventional method, the permanent magnet 16 placed on the rotary table 20 is moved to its S pole by the rotational drive of the motor 18. When rotated about 22, the target 10 is formed in a region corresponding to a predetermined width region sandwiched between the south pole 22 and the north pole 24 of the permanent magnet 16 on the target 10 according to the principle of magnetron sputtering. The electron trapping region 26 extending in the radial direction of the target 10, in other words, the part where sputtering is intense, rotates around the center of the target 10, thereby causing discharge around the center of the circular substrate 8 (in the circumferential direction). As a result, the atoms ejected from the target 10 are deposited.

Therefore, by rotating the permanent magnet 16 in this way, the erosion occurrence position of the target 10 to be sputtered is moved in the circumferential direction, and the sputtering position is moved in the circumferential direction. The resulting atoms adhere to the circular substrate 8 at a high incident angle, and the crystal orientation of the thin film to be formed can also be controlled in the circumferential direction.

Since the sputtering atoms are deposited mainly in the circumferential direction of the circular substrate 80, the thin film formed on the circular substrate 8 must be effectively uniform and homogeneous. This makes it possible to advantageously eliminate modulation, and when a magnetic disk substrate is used as the circular substrate 8 and a magnetic thin film is formed thereon, Co- When forming a Ni film, the higher the incident angle of Co-Ni atoms attached to the substrate, the greater the coercive force. , it has a high coercive force in the circumferential direction.

In addition, in such a sputtering apparatus, since there is no rotation mechanism in the sputtering chamber 2, the generation of dust can be suppressed to a minimum due to the transfer of the substrate. The quality of the thin film formed can also be improved even more effectively.

In addition, in the present invention, since the permanent magnet 16 is rotated by the rotation drive means (18, 20) as in the above embodiment, as shown by the two-dot chain line in FIG. Another N pole 24 is provided integrally with the S pole 22 at a symmetrical position of one N pole 24 with respect to the center of rotation of the permanent magnet 16, that is, the S pole 22, so that the electron trapping region 26 is located at the S pole. It is preferable that the holes are formed symmetrically on both sides of 22.

In addition, in the present invention, as shown above, the permanent magnet 16 has Si2
In addition to the case where the N-pole 2 and the N-pole 24 are arranged in pairs in the radial direction of the target 10, in other words, in the radial direction of the circular substrate 80, as shown in FIGS.
A permanent magnet 16 having a structure in which a south pole 22 and a north pole 24 extending in the radial direction of 0 are arranged facing each other with a predetermined distance apart in the circumferential direction can also be advantageously used. and,
S of the permanent magnets 16 arranged opposite to each other in the circumferential direction
An electron trapping region 26 extending in the radial direction with a predetermined width is formed in a region on the target 10 corresponding to the region between tm22 and the north pole 24.

In particular, as shown in FIG. 5, by using a permanent magnet 16 having a structure in which one magnetic pole is surrounded by the other magnetic pole, the electron trapping region 26 is also confined by the magnetic field. Therefore, the cathode (target 10
) can effectively suppress the scattering of electrons ejected from them. In addition, this figure 4 and 5
Even in the example shown in the figure, the permanent magnets 16 are arranged symmetrically with respect to the center of rotation, and are simultaneously driven to the target by predetermined rotation drive means (18, 20).
0, in other words, around the center of the circular substrate 8, and each radially extending electron trapping region 26,26 rotates around the center of the circular substrate 8 with a phase difference of approximately 180°. It's like being forced to do something.

Furthermore, if the permanent magnet 16 having the magnetic pole arrangement structure as shown in FIGS. 4 and 5 is rotated, the part of the target 10 to be sputtered will be
The length is from the center to the outer circumference in the radial direction, and such a sputtering part in the radial direction is the permanent magnet 1.
Since the target 10 is moved in the circumferential direction by the rotation of the target 1
Since the sputtering area of 0 is not fixed and is moved over the entire area of the target 10 that corresponds to 16 rotations of the permanent magnet, the surface of the target 10 can be eroded uniformly, and its utilization efficiency can be effectively increased. This makes it possible to improve the performance.

Although a few representative examples of the present invention shown in the drawings have been explained above, the present invention should not be construed in any way limited by the illustrated structures and the specific explanations accompanying them. This invention is not intended to be in any way intended to be limited to this invention, and various changes, modifications, improvements, etc. may be made to this invention based on the knowledge of those skilled in the art, without departing from the spirit of the invention. It goes without saying that this includes any of the embodiments.

For example, in all of the concrete examples illustrated, permanent magnets are used as magnet means, but it goes without saying that electromagnets can also be used advantageously in place of this, and also as targets. In order to simplify the explanation, a stationary opposing type circular device is illustrated above, but the present invention can also be advantageously applied to a tray type device using a rectangular target. In that case, for example, the magnet means disposed on the back side of a rectangular target or a circular target used in place of the rectangular target has a rotating structure according to the present invention, and the center of rotation is set at the center of passage of the circular substrate. The circular substrates placed on the pallets are sputtered onto the surfaces of the circular substrates in the circumferential direction by sputtering atoms in the circumferential direction by rotating the substrates at a rotational speed higher than the passing speed of the pallets that hold the substrates. The thin film is formed uniformly in the circumferential direction.

Further, in order to suppress the heating of the anode 6 and the circular substrate 8 placed thereon, and further to suppress the heating of the target 10 as necessary, appropriate cooling means are provided using known sputtering equipment and the like. It goes without saying that the same can be provided, and furthermore, in the embodiment shown in FIGS. 1-3, a radial electron trapping region 26 on the target 10 formed by its permanent magnet 16, in other words In order to control the amount of sputtered atoms deposited in the radial direction of the circular substrates 8 due to the strong sputtering region, a mask or the like that limits the amount of such sputtered atoms flying toward the circular substrates 8 is installed on the circular substrates 8.
and the target 10.

Further, according to the present invention, the number of permanent magnets 16 as magnet means arranged behind the target 10 is not only one or two as illustrated, but also a larger number, and they are arranged around the rotation center circle. In particular, when using a plurality of such magnet means, as illustrated in FIG.
It is desirable to adopt a structure in which they are arranged in symmetrical positions, in other words, rotationally symmetrical positions, in the circumferential direction with respect to the center of symmetry (center of rotation).

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an example of a sputtering apparatus according to the present invention, FIG. 2 is a perspective view showing the relationship between a circular substrate, a target, and a permanent magnet in such an apparatus, and FIG. 1 is an explanatory view in the l-111 direction in FIG. 1 showing the arrangement relationship between a target and a permanent magnet in a device, and FIGS. 4 and 5 are explanations corresponding to FIG. 3 showing an example using different permanent magnets. It is a diagram. 2; Sputtering chamber 4: Gas introduction pipe 6: Anode 8: Circular substrate 10: Target 12: Discharge space 14: DC power supply 1
6: Permanent magnet 18: Motor 20: Rotary table 22: S pole 24: N pole 26: Electron capture area Fig. 1 Ar Fig. 2 Fig. 3 Fig. 2 M

Claims (7)

[Claims] (1) A target and a circular substrate are placed facing each other in a sputtering chamber under reduced pressure in which a discharge gas is present, and a discharge space is formed between them to generate a discharge, thereby sputtering from the target. atoms,
In the sputtering apparatus for depositing on the circular substrate to form a predetermined thin film on the substrate surface, a strong sputtering region of a predetermined width extending in the radial direction is formed on the target portion corresponding to the circular substrate. A magnet means is provided outside the sputtering chamber and behind the target, and a rotation drive means for rotating the magnet means about the center of the circular substrate is provided, and the rotation The strong sputtering region is moved in the circumferential direction of the circular substrate by rotation of the magnet means by the driving means, so that the sputtering atoms are mainly deposited in the circumferential direction of the circular substrate. Characteristic sputtering equipment. (2) The magnet means has one of the S pole and the N pole located at a position corresponding to the center of the circular substrate, and the other at a position corresponding to the peripheral edge of the circular board for a predetermined length. The sputtering apparatus according to claim 1, wherein the sputtering apparatus is arranged in an arc shape. (3) Sputtering according to claim 1, wherein the magnet means is configured such that an S pole and an N pole are arranged facing each other so as to extend in the radial direction of the circular substrate with a predetermined distance apart. Device. (4) Sputtering according to any one of claims 1 to 3, wherein a plurality of the magnet means are provided at symmetrical positions with the center of the circular substrate as the center of symmetry. Device. (5) The sputtering apparatus according to any one of claims 1 to 4, wherein the magnet means is a permanent magnet or an electromagnet. (6) Any one of claims 1 to 5, wherein the circular substrate is a magnetic disk substrate, and the target is made of a magnetic material capable of forming a magnetic thin film on the circular substrate. The sputtering device described in . (7) The sputtering apparatus according to any one of claims 1 to 6, wherein the magnetic thin film is a Co-Ni thin film.