JP2002155357A - Method and system for magnetron sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and a method for magnetron sputtering by which the target utilization efficiency can be improved and which can be well adapted for mass production. SOLUTION: In the magnetron sputtering method where sputtering is performed by generating a magnetic field on the surface of a target by a magnetic-field-generating means provided on the rear side of the target, sputtering is carried out by forming the leading edge of a magnetic field to be generated at the surface of the target into vertical shape and generating an inverted U-shaped magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron sputtering apparatus, and more particularly, to a magnetron sputtering method and a sputtering apparatus with excellent target use efficiency.

[0002]

2. Description of the Related Art Conventionally, a magnet is provided on the back surface side (non-sputtering surface side or rear side (back)) of a target, a magnetic field is formed near the sputtering surface by the lines of magnetic force, and argon gas introduced into a vacuum chamber is used. Increase the frequency of collisions by efficiently confining rare gases such as rare gases and secondary electrons emitted from the target, generate a large number of ions in the atmosphere gas (forming a plasma with a high ion density), and increase the deposition rate. A magnetron sputtering apparatus for sputtering a target is known.

According to this method, when sputtering a target made of a non-magnetic material such as ITO (indium oxide), for example, the magnetic field lines of the magnet pass through the target made of the non-magnetic material, and are desired to be applied to the target surface (from the target surface). A vertical magnetic field (a tunnel-like shape) forms a magnetic field. This magnetic field is sufficient to increase the ion density of the plasma, and the sputtering can be performed smoothly. On the other hand, when a ferromagnetic material such as cobalt or nickel is used as a target and the thickness of the target is made the same as that of a non-magnetic material, the number of lines of magnetic force passing through the target decreases, and the magnetic flux density formed on the target surface decreases. Therefore, it has been difficult for a conventional magnetron sputtering apparatus to use a thick magnetic material as a target.

However, in recent years, it has become necessary to mass-produce a high-quality film made of a ferromagnetic material such as cobalt or nickel, which is often used in semiconductors. It is eager to do. From such a viewpoint, when a magnetic material is used for the target, the thickness is 1 to 2 mm.
By using a magnetic material having a small thickness (FIG. 6), magnetron sputtering of a magnetic target is enabled, and a high-quality film made of a magnetic material is produced.

[0005]

Although the magnetron sputtering method using a magnetic material as a target has been made possible by the above-described method, there are the following problems.

That is, since a thin target is used, the life of the target is extremely short, such as the target is quickly consumed. Therefore, the target must be replaced frequently. In each case of exchanging the target, it is necessary to perform a process of exchanging the target by exposing the inside of the vacuum chamber to the atmosphere, and then evacuating the inside of the chamber again to create a vacuum atmosphere. Had the disadvantage of being unsuitable.

[0007] Further, the magnetic field generated by the conventional magnet has an arc shape, so that its rise is oblique, so that the erosion area is narrow and the utilization efficiency of the target is poor.

Therefore, the present invention has been made in view of such problems, and it is possible to form a magnetic thin film using a magnetic material having a thickness suitable for mass production as a target. It is another object of the present invention to provide a magnetron sputtering method and apparatus which are excellent in production efficiency (dramatically increase the film forming speed), low in cost and economical.

[0009]

That is, in order to solve the above-mentioned problems, the present invention is directed to a method in which a magnetic field generating means provided on the back side of the target is used as a method. In the magnetron sputtering method in which a magnetic field is generated on the surface of the target to perform sputtering, the rising portion of the magnetic field generated on the surface of the target is made vertical, thereby generating a reverse U-shaped magnetic field and performing sputtering. I do.

[0010] Further, as an apparatus embodying the above method, a target to be sputtered, a back plate for placing the target, and a magnetic field on the surface of the target are generated. In a magnetron sputtering apparatus having a magnetic field generating means provided on the back surface side of the target, the magnetic field generating means is disposed directly on the back plate or close to the back plate.

[0011] Further, as a embodied device,
As described in the above, the magnetic field generating means comprises a main body made of a rare earth magnet, a non-magnetic metal covering the side peripheral surface of the main body, and a magnetic metal covering the upper and lower portions of the main body forming the magnetic field. It is characterized by comprising.

Further, as a embodied apparatus, the target is such that the portion on the back side of the target where the magnetic field generating means is arranged (ie, the non-sputtered portion) is smaller than the portion where the sputtering is performed. That is, it is formed thinly.

[0013]

According to the present invention, the magnetic field generating means provided on the back side (non-sputtering surface side) of the target makes the rising portion of the magnetic field on the target surface side (sputtering surface side) perpendicular to the inverted U-shape. By forming a target-like magnetic field and sputtering the target, the erosion region of the target can be spread over the entire sputtering surface of the target,
It is possible to significantly increase the use efficiency of the target.

The distance between the target and the magnetic field generating means is shortened as compared with the conventional apparatus by arranging the magnetic field generating means directly on or close to the back plate for installing the target. Thus, it is possible to form an inverted U-shaped magnetic field by making the rising portion of the magnetic field on the target surface vertical.

Further, in order to strengthen the magnetic field, the magnetic field generating means provided on the back surface side (non-sputtering surface side) of the target has a main body made of a rare earth magnet and a side peripheral surface of the main body covered with a non-magnetic metal. The upper and lower portions of the main body that forms the magnetic field are covered with a magnetic metal, so that a stronger magnetic field, that is, a rising portion of the magnetic field is formed vertically on the target surface, as compared with a conventional magnet. Since a U-shaped magnetic field can be formed, it is possible to expand the erosion region and increase the sputtering efficiency.

Further, by forming the portion (non-sputtering portion) on the back surface side of the target where the magnetic field generating means is arranged to be thinner than the portion to be sputtered, a magnetic field is generated from the thin portion of the target and the target surface side By easily forming a magnetic field on the substrate and forming the erosion portion thicker, it is possible to increase the sputtering efficiency by securing an erosion region.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing the structure of a magnetron sputtering apparatus according to a first embodiment of the present invention. FIG. 2 shows a magnet as a magnetic field generating means.
Is a schematic plan view, and (b) is a schematic sectional side view. FIG.
(A) is an explanatory diagram showing a generated magnetic field, and (B) is a schematic sectional view showing an erosion region of a target sputtered by the magnetic field.

In this apparatus, a substrate (not shown) on which a film is formed by sputtering is horizontally provided in a vacuum chamber (not shown), and Ni (diameter of 2) which is a magnetic target 1 is provided.
A flat circular target 1 having a thickness of 00 mm and a thickness of 5 mm) is arranged to face this substrate (not shown).

On the back side of this target 1 (rear side ... FIG. 1), a back plate 2 is provided on the back side of the target 1. Magnets 3 and 4 are provided at equal intervals at the center and the periphery of the back plate 2. Are located. The magnets 3 and 4 have main bodies 3a and 4a each made of a rare earth element (Nd ₂ Fe ₁₄ B, a compound of three elements in which boron is added to neodymium and iron, and a surface magnetic flux density of 400 mT). Is coated with a non-magnetic material, for example, SuS-304, and upper and lower surfaces 3c and 4c in the magnetic field direction are magnetic materials, for example, SuS-43.
0. Thereby, the main body portions 3a and 4a can be protected from deterioration due to heat, water, and scratches on the surface. (That is, the rare earth element is weak to heat (up to 80 ° C.) and weak to water. In addition, since the magnetic force is strong, it is easily scratched during handling, and the scratch deteriorates quickly due to the scratch.)
Is oriented with the S pole face toward the target 1, and the magnets 4 arranged on all sides are arranged with the N pole face facing the target 1, and these magnets 3 and 4 are fixed by the yoke 6. . The distance (h) between the magnets 3 and 4 from the target 1 is a normal magnetron sputtering apparatus (FIG. 6).
Is shorter than the distance (H).

As described above, since the magnets 3 and 4 are made of rare earth and the distance between the target 1 and the magnets 3 and 4 is short, the magnets 3 and 4 are indicated by arrows in the figure (indicated by solid lines in FIG. 3 (a); broken lines indicate conventional magnetic fields for comparison), the target 1 is substantially perpendicular to the magnet 4. An inverted U-shaped magnetic field is formed in the shape of an inverted U-shape, and the magnetic field can be generated toward the magnet 3. In other words, the lines of magnetic force are formed in a shape that springs vertically from the surface of the target 1. For this reason, the erosion area of the target 1 can be uniformly spread over the entire surface of the target and almost entirely (see the solid line in FIG. 3 (b). The broken line indicates the erosion area by a conventional magnetic field for comparison. .). As a result, the utilization efficiency of target 1 is increased by 35%.
(The conventional utilization efficiency is 20 to 25%.)

As described above, the magnetron sputtering apparatus of the present invention is constituted. A case where a Ni target, which is a magnetic material, is used using this apparatus will be described.

First, the vacuum pump is driven to make the inside of the vacuum chamber a predetermined degree of vacuum, and a discharge gas is supplied from the discharge gas supply source into the vacuum chamber. Then, a voltage is applied to the target 1 from the 13.56 MHz high frequency power supply by the target electrode, thereby generating plasma near the surface of the target 1 material.

A substantially U-shaped magnetic field penetrates through the target 1 in a substantially vertical shape formed by magnets 3 and 4 provided on the back side of the target 1 so that the plasma formed in the space is vertically extended from the surface of the target 1. In this case, the shape of the film springs in the direction, and the vicinity of the substrate is activated by the plasma, so that the film forming speed can be drastically increased. Moreover, since the magnetic field in this space uniformly spreads over the surface of the circular target 1 and almost all over, sputtering is performed by forming a wide erosion area, and sputtered particles from a wide range of the target 1 reach the substrate. Thus, a uniform Ni thin film is formed on the substrate surface.

In the above embodiment, the magnets 3 and 4 are made of a rare earth earth body 3a, 4a, the side peripheral surfaces 3b, 4b of the body parts 3a, 4a are non-magnetic, and the upper and lower surfaces 3c, 4c are magnetic. Although it was configured to be protected by the body, a magnetic lens 8
By providing (FIG. 4), a concentrated vertical magnetic field can be formed, and a stronger vertical magnetic field can be formed on the surface of the target 1.

In the above embodiment, the target 1 is formed thin. For example, the target 1 is formed thin (about 1 to 2 mm) only in the portion where the magnets 3 and 4 are arranged, and the erosion portion is made thick (2 mm). Above) to form (FIG. 5)
This makes it possible to further improve the use efficiency of the target 1.

Further, by finely adjusting the arrangement of the magnets 3 and 4, the magnets 3 and 4 can be used to improve the target efficiency without being particular about the size and shape of the target.

[0028]

As described above, according to the magnetron sputtering method and the apparatus of the present invention, the magnetic field generating means is provided directly or close to the back plate of the target, so that the magnetic field generating means is perpendicular to the surface of the target. A remarkable effect that a strong magnetic field can be formed was obtained.

Further, the target is made of a magnetic material, and the magnet on the back side of the target is made of a rare earth covered with a non-magnetic material or the like, so that a strong vertical magnetic field is formed on the surface of the target. Even if a target made of a thick magnetic material is used, the erosion area can be expanded over the entire sputtering surface of the target, and a remarkable effect of enabling efficient sputtering can be obtained.

In addition, since a thick magnetic target can be used, the life of the target can be extended. As a result, there is an advantage that the production can be performed efficiently, the method is suitable for mass production, and a high-quality and low-cost film can be produced.

Further, since the magnetic field generating means is composed of a rare earth element covered with a magnetic material or the like, a magnetron sputtering apparatus in which a strong magnetic field is formed with a simple configuration can be constructed, and the magnet can be used for a long time. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional schematic view showing a magnetron sputtering apparatus of the present invention.

FIG. 2 shows a magnet as a magnetic field generating means provided in a magnetron sputtering apparatus, (a) is a schematic plan view,
(B) is a schematic sectional side view.

FIG. 3A is a schematic explanatory view showing a magnetic field on the surface of a target, and FIG. 3B is a schematic sectional view showing an erosion region of the target.

FIG. 4 is a schematic sectional view showing another embodiment of a magnet as a magnetic field generating means.

FIG. 5 is a schematic sectional view showing another embodiment of the magnetron sputtering apparatus and showing a magnetic field when a target is processed.

FIG. 6 is a schematic sectional view showing a conventional magnetron sputtering apparatus.

[Explanation of symbols]

 1 ... Target

Claims (4)

[Claims] In a magnetron sputtering method in which a magnetic field is generated on a surface of a target by a magnetic field generating means provided on a back surface side of the target and sputtering is performed, a rising portion of a magnetic field generated on the surface of the target is made vertical. A magnetron sputtering method characterized by generating an inverted U-shaped magnetic field and performing sputtering. 2. A magnetron sputtering apparatus comprising: a target to be sputtered; a back plate for mounting the target; and a magnetic field generating means provided on the back side of the target to generate a magnetic field on the surface of the target. A magnetron sputtering device, wherein the magnetic field generating means is disposed directly on or close to the back plate. 3. The magnetic field generating means comprises a main body made of a rare earth magnet, a non-magnetic metal covering the side peripheral surface of the main body, and a magnetic metal covering the upper and lower portions of the main body forming a magnetic field. The magnetron sputtering apparatus according to claim 2, wherein 4. The magnetron sputtering apparatus according to claim 2, wherein the target is formed such that a portion of the rear surface where the magnetic field generating means is disposed is thinner than a portion to be sputtered.