JPH1046330A - Opposed target type sputtering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opposed target type sputtering device which does not cause film quality deterioration even when supplied power is made larger and is suitable for industrial manufacturing. SOLUTION: In the opposed target system sputtering device, a pair of targets 110a, 110b are disposed to face each other at prescribed interval in a vacuum tank 10, magnetic field generating means 130a, 130b composed of permanent magnets are provided outside the target along the outer periphery of the target, magnetic field for catching plasma is formed so as to surround confronting space between the targets and then sputtering plasma is generated in the confronting space to form a thin film on a substrate 20 arranged at a side of the opposed space. In this case, a housing part which projects from a wall surface of the vacuum tank to inside of the tank along the outer periphery of the target so as to surround the target and a supporting part thereof and which is shut off from inside of the tank and is taken in and out from and to the outside of the tank is provided and the permanent magnet as the magnetic field generating means is housed therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of arranging a pair of targets facing each other at a predetermined interval in a vacuum chamber, generating a sputter plasma in a space between the targets, and forming a sputter plasma in a space facing the space. The present invention relates to a facing target type sputtering apparatus in which a film is formed on a substrate arranged on the side.

[0002]

2. Description of the Related Art The above-mentioned opposed target type sputtering apparatus comprises:
JP-B-63-20303, JP-B-63-203 filed by the present inventors
No. 04, Japanese Patent Publication No. 62-14633, etc., are already known, and the configuration shown in FIG. 1 is used as a basic configuration. That is, targets 110a and 110b arranged to face each other with a space 120 of a predetermined distance therebetween in the vacuum chamber 10, and a target that generates a magnetic field so that the magnetic flux uniformly covers the side surface of the outer edge of the opposed space 120 Magnetic field generating means 130 provided on the back of each of 110a and 110b
In this configuration, a sputtering unit including a and 130b is provided, and the substrate 20 is disposed so as to face the facing space 120 by a substrate holder 21 provided on the side thereof. Note that 140a, 1
40b is the target 110a, 110b of the target unit 100a, 100b.
Is a shield for protecting portions other than the front surface from being sputtered.

Accordingly, an exhaust port is provided by an exhaust system (not shown).
After evacuating the vacuum chamber 10 through 30, a sputtering gas such as argon is introduced from an introduction port 40 by gas introduction means (not shown), and a sputter power
When the sputtering power is supplied by using the shields 140a and 140b and thus the vacuum chamber 10 to the anode (anode) (ground) and the targets 110a and 110b to the cathode (cathode), the target
Sputter plasma is formed in the opposing space 120 between 110a and 110b to perform sputtering, and targets 110a and 1b are formed on the substrate 20.
A thin film having a composition corresponding to the composition of 10b is formed.

At this time, the target 110
Since a magnetic field is formed in a direction perpendicular to the planes of the a and 110b, high-energy electrons are confined in the facing space 120 between the targets 110a and 110b, and sputter plasma is generated. This is accelerated, and the sputtering speed is increased, so that a high-speed film can be formed. In addition, the substrate 20
As with a conventional typical sputtering apparatus, such as a two-pole sputtering apparatus in which a substrate and a target are opposed to each other, a target 11 is used.
0a, 110b, so that they are arranged on the sides of the targets 110a, 110b, so that the collision of ions and electrons on the substrate 20 is extremely small, and the heat radiation from the targets 110a, 110b is also small and the substrate temperature is small. Rise is also small. Therefore, a low-temperature film can be formed. As described above, the magnetic thin film has the feature of being able to form various materials at low temperatures and high speeds, including magnetic materials, for which high-speed film formation has been difficult with conventional magnetron sputtering.
It is used for manufacturing thin-film magnetic recording media and the like.

[0005] However, a rectangular or circular target is usually used in this method, but regardless of the shape of the target,
It was found that erosion tends to concentrate at the center of the target surface which is eroded by spattering, and it is necessary to improve the use efficiency of the target (IEEE Trans on Ma).
gnetics MAG-17, pp.3175-3177 (1981)). When a rectangular target is used, the target erosion pattern becomes asymmetric with respect to the center of the target, a film thickness distribution occurs even in the width direction of the substrate, and the productivity and the uniformity of the thin film also need to be improved. I understood that.

On the other hand, the present inventors have disclosed Japanese Patent Publication No. Hei 3-2231.
In Japanese Unexamined Patent Publication No. 63-54789 and JP-B-63-54789, as an improved technique for expanding the target erosion characteristics over the entire target surface, a magnetic field generating means is provided around the outside of each target, and a core is provided at the magnetic pole end portion which is the magnetic field generating portion. A configuration was proposed in which the magnetic field was generated around the target.

[0007] With this configuration, the magnetic field is formed between the cores directly opposed to each other without passing through the target, so that the magnetic field distribution is hardly influenced by the magnetic permeability, the saturation magnetization of the target material, and the thickness of the target. A magnetic field for confining the sputter plasma was formed around the outer periphery of the target along the outer periphery thereof, and the erosion region was expanded from the center of the target to the periphery of the outer edge, so that the target utilization efficiency was greatly improved. However, it has been found that there is a disadvantage that the discharge voltage is increased during sputtering, and stable sputtering cannot be performed unless the sputtering gas pressure is high.

In order to solve this problem, the present inventors have developed a technique for more uniformly expressing the plasma restraint conditions over the entire area of the target surface, which is a feature of the facing target sputtering method. And Japanese Patent Publication No. 5-75827. These technologies generate and confine the sputter plasma, in addition to the magnetic field lines (magnetic field) perpendicular to the target surface in the conventional facing target type sputtering, and arc-shaped magnetic force lines that close to the target surface in the space near the entire outer periphery of the target surface. And an electron reflecting means for reflecting electrons near the magnetic pole tip is provided. In this technique, high-energy electrons flying in the space between the opposing targets drift in the space and drift around the outer periphery of the target without being absorbed by the magnetic poles over the entire circumference due to the electromagnetic field near the surface of the outer periphery of the target. Therefore, the ionization efficiency of the sputtering gas is remarkably increased as a whole, and a technology free from the above-mentioned problem has been realized.

As a result, it has become possible to increase the sputtering efficiency over the entire area of the target. It is expected as an ultra-high-density recording material using the sputtering equipment of this technology
Co-Cr, Co-Cr-Ta alloy thin film is made of polyethylene terephthalate (PET) film or polyethylene naphthalate (P
EN) As a result, it was confirmed that a magnetic thin film with excellent magnetic properties and microstructure could be produced on a low-temperature substrate at 150 ° C (J. Mag. Soc. Jpn., 18, Suppl. S1, pp. 19).ー 2, p
p.331-334, etc.). With this sputtering technology, it is possible to form a thin film with excellent characteristics such as fine structure that cannot be realized by the conventional sputtering method where the substrate and the sputtering source are opposed, and it is possible to uniformly erode the entire target, and a rectangular target was used. In this case as well, the symmetry of the target erosion pattern with respect to the center of the target was dramatically improved.

However, even in this improved facing target type sputtering apparatus, recoil gas particles and sputter particles sputtered from the target surface change to a state in which they are scattered from all sides of the space between the targets into the vacuum chamber. Absent. For this reason, even if sputtering can be performed uniformly from the entire surface of the target and a thin film having a uniform film thickness distribution can be realized on the substrate with good control, only a part of the side space of the target facing the substrate is formed as a thin film. In addition, there is a problem that the gas built in the vacuum chamber wall is released during sputtering due to particles scattered on the vacuum chamber wall, and as a result, the quality of a thin film formed on the substrate is deteriorated.

On the other hand, the inventors of the present invention have previously disclosed in Japanese Patent Application No.
In the specification of JP-A-8-162676, a facing space partitioned type facing target sputtering apparatus in which the facing space having the following configuration is partitioned by a target except for the substrate side is proposed. That is, the space is formed by a pair of first targets opposed to each other with a space of a predetermined distance therebetween and a second target arranged so as to cover a side surface of the space excluding the opening facing the substrate. Magnetic field generating means for generating a magnetic field for restraining the sputter plasma is arranged along the outer periphery of each of the first targets so that the magnetic poles face each other near the outside thereof; A cylindrical magnetic field surrounding the pair of first targets by the generating means, a magnetic field closed in an arc shape on the inner surface from the magnetic pole near the surface of the outer edge of the first target, and a magnetic field closed near the surface of the second target. A magnetic field parallel to the surface and a magnetic field closed in an arc shape on the inner surface from the magnetic pole are formed near the surfaces of both side edges adjacent to the magnetic field generating means of the second target. Electron reflecting means for reflecting electrons is provided at the magnetic pole end portion facing the partitioned space and at the end of the opening of the partitioned space of the second target, and a sputter plasma is generated in the partitioned space. This is a facing target type sputtering apparatus in which a thin film is formed on an arranged substrate.

In this apparatus, as described above, all the sides except for the opening on the side facing the substrate in the space between the pair of first targets facing each other are surrounded by the second target in the partitioned space. The high density plasma is generated and confined on almost all surfaces of each target by the interaction of the electrons confined to the above magnetic fields via the reflection means, and almost uniform sputtering of all the surfaces of all targets is realized. The problem has been resolved.

[0013]

By the way, in the above-mentioned opposed target type sputtering apparatus, it was recognized that when the sputtering power applied to increase the film forming speed was increased, the quality of the deposited film tended to decrease. . This trend is
This was particularly remarkable in the device provided with the electron reflecting means. This problem is very significant in industrial production where production speed is a major cost factor. The present invention has been made in view of such a problem, and an object of the present invention is to provide a facing-target-type sputtering apparatus suitable for industrial production without deterioration in film quality even when the input power is increased.

[0014]

The above object is achieved by the present invention described below. That is, according to the present invention, a pair of targets are opposed to each other at a predetermined interval in a vacuum chamber, and a magnetic field generating means made of a permanent magnet is provided along the outer periphery of the targets outside the target to form a facing space between the targets. In a facing target type sputtering apparatus, a plasma capturing magnetic field is formed so as to surround the substrate, a sputter plasma is generated in the facing space, and a thin film is formed on a substrate arranged in the direction of the facing space. A storage portion is provided which protrudes from the vacuum chamber wall surface along the outer periphery to the inside of the tank so as to surround the target and its supporting portion, and which is shielded from the inside of the tank to be taken in and out from the outside of the tank. This is a facing target type sputtering apparatus characterized by storing therein.

The present invention has been made as follows. That is, when the cause of the above-mentioned problem was examined in various ways, this problem was mainly caused by the impurity gas generated when the permanent magnet of the magnetic field generating means was heated to a high temperature. The inventors have found that the increase in the number of electrons flying to the substrate accompanying the decrease in the plasma trapping magnetic field is also caused, and this has been made. In the present invention, since the permanent magnet of the magnetic field generating means is provided substantially in the atmosphere outside the vacuum chamber by the above configuration, the above-described problem of the impure gas has been completely solved. Furthermore, due to the configuration outside the vacuum chamber, the natural cooling is larger in the atmosphere than in the vacuum in the chamber, and the cooling means for forced cooling can be freely designed as necessary, since there is no restriction on the space. The problem of magnetic force drop was also solved.

From the gist, it is apparent that the present invention can be widely applied to a facing target type sputtering apparatus in which a permanent magnet of a magnetic field generating means is provided along the outer periphery of the facing target. In particular, in the case where the magnetic poles of the magnetic field generating means protrude from the front surface of the target to the facing space so that the entire surface of the target is uniformly sputtered, the problem that the protruding portion of the magnetic field generating means is heated by contact with the sputter plasma is remarkable. And the effect is great. Furthermore, in the case where the electron reflecting means is provided at the tip of the magnetic field generating means, the electron reflecting means may be sputtered in some cases, and this problem is a major problem from the viewpoint of stable production, and the present invention is lacking in industrial production. It will not be possible. Hereinafter, the present invention will be described in detail based on examples.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present embodiment is directed to a conventional target-target type sputtering apparatus shown in FIG.
100a and 100b are changed to target portions 100a and 100b provided with electron reflecting means shown in FIGS. 2 and 3 having the same basic configuration as that disclosed in Japanese Patent Publication No. 5-75827, and FIG. FIG. 3 is a side sectional view of the target portion 100a of the example, and FIG.
It is sectional drawing in the B line. Therefore, the target portions 100a, 100
The configuration excluding b is the same as that of the conventional example of FIG. 1 described above, and a description thereof will be omitted. 1 to 3, the same symbols are used for the same symbols. As shown in FIG. 2, the target portions 100a and 100b of this example are
Removably mounted on one. In addition, FIG.
The target unit 100a has the same configuration as the target unit 100a except that the magnetic pole arrangement of the permanent magnets of the magnetic field generating means 130a and 130b is reversed.

The target 110a is replaceably mounted on the front surface of the cooling table 150a by bolts 111a at regular intervals around its periphery. A cooling groove 151a is provided on the front of the cooling stand 150a in FIG.
As shown in FIG. 5, the partition wall 152a is provided in a zigzag manner, and when the target 110a is mounted, a cooling jacket is formed. A cooling medium supply port 153a and an outlet 154a are provided at both ends of the cooling groove 151a, so that the cooling water can be circulated to directly cool the target 110a. Therefore, cooling with very high cooling efficiency can be performed, and it is possible to cope with high-speed film formation. The cooling stand 150a is a packing 15 made of an electrically insulating material.
It is attached to the support plate 160a by bolts 156a at regular intervals via 5a.

The support plate 160a is provided with a storage portion 131a for storing the magnetic field generating means 130a so as to surround the outside of the target 110a with a predetermined gap G along the periphery thereof, as shown in FIG.
The target 110a is provided inside the tank so as to protrude from the front surface of the target 110a by a predetermined length d. As shown in the figure, the storage portion 131a has a structure in which holes of a predetermined depth opened outside the tank for inserting and removing the permanent magnet of the magnetic field generating means 130a from outside the tank are formed in the block at a predetermined pitch, and the magnetic field generating means 130a is this storage section 131a
In each of the holes, a rod-shaped permanent magnet is inserted in the arrangement of the magnetic poles shown in the drawing and fixed with a stopper 132a, and a large number of permanent magnets are arranged side by side around the target 110a at a constant pitch. The storage section 131a is made of a conductive material, and is configured to also act as a part of an electron reflection unit described later. In the present embodiment, the storage portion 131a and the support plate 160a are made of a structural material such as a metal having good heat conductivity, specifically, an aluminum block.
The cross section shown in the figure is cut into an inverted T-shape with a C lathe to produce a predetermined frame, and the bottom portion of the frame is used as a support 160a of a support portion.
Holes were drilled in the vertical portion from the bottom side at a predetermined pitch to form a storage portion, and a seamless integrated structure was formed. This completely shuts off the inside of the tank, there is no vacuum leakage, and the support plate 160a
As a result, a storage portion 131a was obtained in which the stored permanent magnets could be sufficiently cooled only by natural cooling due to the heat radiation from the housing.

At the tip of the storage section 131a, an electron reflecting plate 170a of an electron reflecting means which is maintained at a negative potential capable of reflecting electrons reaching here is provided with a mounting section around the target 110a as shown in the figure. Is provided so as to cover the bolt 111a. In this example, the electron reflector 170a
Is made of a high-permeability magnetic material, specifically permalloy,
The configuration is such that the core of the magnetic field generating means 130a is also used. As described above, the target portion 100a has a unit configuration in which the entirety is provided on the support plate 160a. Then, as shown in the drawing, the target portion 100a attaches the support plate 160a to the tank wall of the vacuum tank 10.
It is installed in the vacuum chamber 10 by being attached to 11 with bolts 162a at regular intervals via a packing 161a made of an electrically insulating material. Therefore, at the time of cleaning or the like, the target portion 100a can be removed, and can be performed very efficiently.
A great effect can be obtained on improving the maintainability and the productivity as a whole.

The above-mentioned magnetic field generating means 130a, 130b are provided outside the targets 110a, 110b, and the electron reflecting plates 170a, 130b extend from the magnetic pole ends to the mounting portions around the targets 110a, 110b.
The basic configuration of the target portions 100a and 100b provided with 170b is the same as the target portion of the facing target type sputtering apparatus disclosed in the above-mentioned Japanese Patent Publication No. 5-75827, and by the same operation, as disclosed in the publication, As described above, a high-quality thin film can be formed, and almost the entire surface of the targets 110a and 110b can be uniformly sputtered. That is, with this configuration, the target
The following magnetic lines of force for plasma capture are formed in the facing space 120 in the facing space 110a, 110b. The first is the magnetic field generating means 130a, 130b
Are perpendicular magnetic force lines formed in a cylindrical shape in the vertical direction of the targets 110a and 110b so as to surround the targets 110a and 110b and the opposing space 120 between the magnetic poles. The second is that the magnetic field generating means 130a, 13b is provided on the outer edge of each of the targets 110a, 110b.
Auxiliary lines of magnetic force are formed in an arc shape on the front surfaces of the targets 110a and 110b from the tips of the electron reflection plates 170a and 170b also serving as the core of 0b.

The target 110a, 1
The γ-electrons emitted from the center of the surface of 10b and accelerated by the cathode potential drop portion are constrained by the lines of perpendicular magnetic force in a spiral shape and reciprocate between the targets 110a and 110b. on the other hand,
The γ-electrons generated at the outer edges of the targets 110a and 110b reach the electron reflectors 170a and 170b having a negative potential capable of reflecting the electrons by being constrained by the auxiliary magnetic lines of force. It returns while being constrained by the lines of magnetic force, and partly returns to the center of the opposing space 120.

Accordingly, γ-electrons are accumulated in the facing space 120 to generate high-density plasma, thereby realizing sputtering at a low voltage and a low gas pressure, and forming a high-quality thin film with less internal distortion and less mixing of sputter gas. it can. In addition, a plasma trapping magnetic field similar to that of a well-known flat-plate magnetron sputter is formed on the outer edge of each of the targets 110a and 110b by the auxiliary magnetic force lines, and γ electrons and the like reflected by the electron reflecting plates 170a and 170b are effectively targeted. 110a, 110b are trapped in the vicinity of the outer edge surface of each, the plasma density of this outer edge can be increased, so that substantially uniform sputtering is realized up to the outer edge,
A highly efficient film can be formed in which the targets 110a and 110b are used almost uniformly over the entire surface.

By the way, in the above-described configuration, the front ends of the magnetic field generating means 130a and 130b protrude from the front surfaces of the targets 110a and 110b, and the electron reflecting plates 170a and 170b are provided. 130b, especially its tip is radiant heat from the targets 110a, 110b, the electron reflector 170
a, 170b are heated by collision of electrons or the like with the storage unit 131 having good thermal conductivity directly connected to the outside of the tank under the atmosphere in the present embodiment.
Since it is stored in a and 131b, it can be maintained at a temperature that does not hinder practical use. If natural cooling is not enough,
Arrange cooling pipes at 160a and 160b, and furthermore, storage sections 131a and 13
Force cooling may be performed by making 1b into a jacket configuration or the like.
In this embodiment, the storage part and the support plate, which are completely free from gas leakage, are integrally formed. However, it is obvious from the gist of the present invention that a structure in which each part is connected by welding or the like can be applied. In addition, the cooling part is also good, and the storage part where holes suitable for storing the bar-shaped magnet are drilled in the block is shown,
The structure of the storage portion is not limited, and the storage portion can be applied according to the purpose such as a shape suitable for the shape of the permanent magnet to be used, such as a continuous groove, or a structure that is easy to cool.

Furthermore, although the entirety of the target portion having good maintenance workability can be removed from the vacuum chamber, the storage section may be directly protruded from the vacuum chamber wall and the target cooling table may be installed on the vacuum chamber wall. . The present invention can be applied to any configuration in which the permanent magnet of the magnetic field generating means can be disposed from outside the vacuum chamber by blocking the interior of the vacuum chamber so that the magnetic poles face the targets facing each other from outside the vacuum chamber.

As described above, according to the present storage unit configuration, the radiant heat from the side target is further applied, the leading end of the storage unit is located in the partitioned space, and the space facing the permanent magnet of the magnetic field generating means has severe thermal conditions with respect to the permanent magnet. The above-mentioned Japanese Patent Application No. Hei 10-120, in which a target is also provided on the side surface excluding the side surface facing the substrate 20 of 120, and a sputter plasma is formed in a partitioned space defined by the target except for an opening on the side surface facing the substrate 20. 8 ー
It is particularly preferably applied to the sputtering apparatus proposed in the specification of Japanese Patent No. 162676.

[0027]

As described above, according to the present invention, the storage portion, in which the permanent magnet of the magnetic field generating means is shut off from the inside of the vacuum tank and is stored from the outside of the tank, is protruded inward from the tank wall of the vacuum tank. By arranging it around the target, the effect of the gas emitted from the permanent magnet on the film formation is eliminated, and the thermal deterioration of the permanent magnet is also prevented. This has a great effect on improvement. As described above, the present invention makes a great contribution to the realization of an industrial scale facing target type sputtering apparatus requiring high-speed film formation.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic configuration of a conventional opposed target type sputtering apparatus.

FIG. 2 is a schematic side sectional view of a target section according to the embodiment of the present invention.

FIG. 3 is a schematic sectional view taken along line AB in FIG. 2;

DESCRIPTION OF THE SYMBOLS 10 Vacuum chamber 20 Substrate 30 Exhaust port 40 Inlet port 50 Sputter power source 100a, 100b Target unit 110a, 100b Target 120 Opposing space 130a, 130b Magnetic field generating means 140a, 140b Shield 150a, 150b Cooling stand 160a, 160b Support plate 170a, 170b Electronic reflection plate

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[Procedure amendment]

[Submission date] September 19, 1996

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic configuration of a conventional opposed target type sputtering apparatus.

FIG. 2 is a schematic side sectional view of a target section according to the embodiment of the present invention.

FIG. 3 is a schematic sectional view taken along line AB in FIG. 2;

[Reference Numerals] 10 vacuum chamber 20 the substrate 30 outlet 40 inlet 50 sputtering power source 100a, 100b target unit 110a, 1 1 0b target 120 facing the space 130a, 130b field generating means 140a, 140b shield 150a, 150b cooling stage 160a, 160b Support plate 170a, 170b Electronic reflection plate

Claims (8)

[Claims] 1. A pair of targets are opposed to each other at a predetermined interval in a vacuum chamber, and a magnetic field generating means made of a permanent magnet is provided along the outer periphery of the targets on the outside thereof to form an opposed space between the targets. Form a magnetic field for plasma capture to surround, generate sputter plasma in the opposed space,
In a facing target type sputtering apparatus in which a thin film is formed on a substrate arranged in the direction of the facing space, the target and the supporting portion are protruded from the vacuum chamber wall surface to the inside of the chamber along the outer periphery so as to surround the supporting part. A facing target type sputtering apparatus characterized in that a storage portion is provided which is isolated from the inside of the tank for taking in and out of the tank, and a permanent magnet of a magnetic field generating means is stored in the storage portion. 2. A permanent magnet is stored in such a manner that a front end portion of the storage portion protrudes from the target surface toward the opposing space, and a permanent magnet is stored so that its magnetic pole is located at the protruded position. The facing target type sputtering apparatus according to claim 1, wherein a magnetic field in a sputtering mode is formed. 3. The facing target type sputtering apparatus according to claim 2, further comprising an electron reflecting means for reflecting electrons in the sputter plasma inside the tank at the tip of the storage section. 4. The facing target type sputtering apparatus according to claim 1, wherein said housing portion is an integral molded body having no seam. 5. The facing target type sputtering apparatus according to claim 4, wherein said storage section and said support section supporting said storage section and attaching to said vacuum chamber are integrally formed. 6. The integrated molded body is an inverted T-shaped molded body cut out of an aluminum block, a bottom portion of which is a support portion, and a hole for accommodating a permanent magnet in a vertical portion is fixed from the bottom side. 6. The opposed target type sputtering apparatus according to claim 5, wherein the storage section is formed by piercing at a pitch. 7. The facing target type sputtering apparatus according to claim 1, wherein the target portion is a unit configured to be attached to the support portion, and is detachably attached to the vacuum chamber via the support portion. . 8. The facing target type sputtering apparatus according to claim 1, further comprising a side target surrounding a side surface of the facing space excluding a side surface facing the substrate.