JPH05148639A - Magnetron cathode electrode - Google Patents

Abstract

PURPOSE:To move the distribution of magnetic lines of force on a target surface and to form a uniform thin film on the surface of a large-sized rectangular substrate by moving a magnet assembly in a prescribed locus on the rear surface of the target assembly of the magnetron cathode electrode of a sputtering device. CONSTITUTION:The target assembly 22 provided with the flat planar target of a relatively wide area on the magnetron cathode electrode 20 in a sputtering chamber is disposed and the magnet assembly 32 is disposed on the rear surface thereof to form the distribution of the magnetic lines of force in an annular tunnel form on the front surface of the target at the time of forming the thin film with the target by sputtering on the surface of the large-sized substrate with the sputtering device. The sputtering is executed while the electrode assembly 32 is moved along the prescribed locus in the internal space 38 of the electrode 20 by a driving motor system 42. The magnetic field region of the target surface is moved by the movement of the magnet assembly 32 and the target surface is uniformly bombarded with the discharge gaseous ions of Ar, etc., by which the nonuniformity of the target consumption is ameliorated and the uniform thin film is formed on the large-sized substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron cathode electrode, and in particular, it produces a thin film having a uniform thickness and a uniform thickness on a substrate surface having a relatively large area, and effectively uses the entire surface of the target to uniformly consume it. It relates to the structure of a magnetron cathode electrode.

[0002]

2. Description of the Related Art Various methods have been conventionally known for the method of electrodes used in thin film production by sputtering. Among them, industrially, the magnetron method is most often used because the high film forming speed is the main reason. There are various electrode shapes for magnetron type electrodes. The various electrode shapes were edited by JL Vossen and W. Kern, for example, in 1978 in Academic
75 of "ThinFilm Processes" published by Academic Press
Pp. To 173, or pp. 186 to 189 of the "Thin Film Handbook" edited by the Japan Society for the Promotion of Science, Thin Film 131st Committee and published by Ohmsha in 1983. Among them, the planar magnetron with a target having a rectangular plane is industrially the most powerful.

[0003]

As is already known, when a thin film is formed on a large-area substrate by a sputtering device using a rectangular flat plate-shaped magnetron cathode electrode, the device becomes large and the target is unsatisfactory. Unevenness of uniform consumption, non-uniform ion bombardment on target surface and non-uniformity of sputtering film in substrate due to non-uniformity of plasma spatial density distribution, and particle generation due to non-uniform ion bombardment on target surface There was such a problem.

In view of such a problem, the present inventors first filed a patent application (Japanese Patent Application No. 3-194298) to solve the problem associated with non-uniform impact of a target in a rectangular flat plate magnetron cathode. We proposed an electrode structure that forms a thin film on a relatively large rectangular substrate in a stationary opposing state, regardless of the translational transfer method in which the relative positional relationship of the substrate to the target is translational. In this patent application, a plurality of magnet units independently having a function as a magnetron cathode are provided, and a unit magnet assembly configured by adjoining these magnet units to each other is incorporated into a magnetron cathode electrode, and a unit magnet assembly is provided. As a whole, there is disclosed a configuration in which the rectangular magnetron cathode is operated while performing an oscillating motion substantially parallel to the cathode surface, and a method of operating the same.

An object of the present invention is to provide another configuration example of the magnetron cathode electrode structure of the previously proposed sputtering apparatus, which solves the problem caused by non-uniform ion bombardment of the target and has a relatively large rectangular shape. An object of the present invention is to provide a magnetron cathode electrode for forming a thin film on a substrate in a stationary facing state without using a translational movement method in which a relative positional relationship of the substrate to a target is a translational relationship.

[0006]

A magnetron cathode electrode according to the present invention is applied to a sputtering apparatus for forming a thin film, and is provided with a flat target having a relatively wide flat surface facing a substrate on which the thin film is formed. A magnet assembly that forms a magnetic field distribution in the form of an annular tunnel near the surface of the target is arranged on the back side of the target, and a drive mechanism that moves this magnet assembly along a predetermined trajectory in the space inside the electrode, A link mechanism that retains the shape of the magnet assembly and locally deforms the shape of the magnet assembly according to the orbital shape, forms a magnetic field distribution corresponding to the shape of the magnet assembly, and The magnetic field line distribution is configured to move on the surface of the target along with the movement. The magnetic field line distribution forms a region of a closed annular tunnel, which moves at a predetermined speed over the surface of a large area target. Electron drift motion occurs in the area of the annular tunnel. In the above configuration, preferably, the magnet assembly includes a central magnetic pole group in which a plurality of magnets are arranged in a row, and an outer peripheral magnetic pole group including a plurality of magnets arranged so as to surround the central magnetic pole group. .. The magnetic force lines are distributed between the central magnetic pole group and the outer magnetic pole group, and the distribution of the magnetic force lines forms the annular tunnel-shaped region.

[0007]

According to the present invention, the magnet assembly is arranged in the electrode housing on the rear surface side of the target so as to form a magnetic field region having an annular tunnel shape near the surface of the target, and a predetermined trajectory is provided by the drive mechanism. It is installed on the link mechanism that moves. Therefore, the magnet assembly moves along the predetermined track as the link mechanism moves. The magnet assembly includes a central magnetic pole group and an outer magnetic pole group, and has a locally deformable structure. Therefore, when moving along the trajectory, the curved portion is deformed so as to match the trajectory. The predetermined track is formed in a desired shape inside the electrode housing on the back side of the target. The track is formed in a shape that widely extends to the target, and is formed by the timing belt, a plurality of support pulleys that support the timing belt, and one drive pulley that drives the timing belt.

When the magnet assembly is moved along the track by the drive mechanism and the link mechanism, the magnetic field region is also moved while locally deforming the shape formed on the surface of the target by the magnet assembly. In this way, the electron drift generation region widely moves on the target surface. If the moving speed of the magnetic field region is sufficiently high, most of the target surface can always be exposed to ion bombardment in a relatively short time. Therefore, by appropriately setting the movement locus of the magnet assembly in the electrode housing, it is possible to form a thin film having a uniform thickness on the substrate surface in a stationary state of the substrate in an appropriate combination of the rectangular substrate and the rectangular target. ..

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optimum embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view showing the overall structure of a sputtering apparatus, and FIG. 2 is a sectional view showing the internal structure of the main part of a magnetron cathode electrode. In FIG. 1, the sputtering apparatus is configured by serially connecting a substrate tray insertion chamber 1, a sputtering chamber 2 for forming a thin film on the surface of a substrate mounted on the tray, and a substrate tray unloading chamber 3. Each of the chambers 1, 2 and 3 independently has an exhaust system, and maintains and manages a vacuum state. Substrate tray insertion chamber 1
A gate valve 4 is disposed between the sputtering chamber 2 and the sputtering chamber 2, and a gate valve 5 is disposed between the sputtering chamber 2 and the substrate tray unloading chamber 3. The sputtering chamber 2 is kept in a vacuum state while forming a thin film. Also, the substrate tray insertion chamber 1 and the substrate tray unloading chamber 3
Are opened to the atmosphere by leak valves 6 and 7, respectively, and are exhausted in the directions of arrows 10 and 11 by exhaust pumps (not shown) via exhaust pipes 8 and 9. At the left end of the substrate tray insertion chamber 1 in FIG.
The right end of the substrate tray take-out chamber 3 is an exit door 13.

The tray 14 on which the substrate is mounted is sent from the entrance door 12 to the substrate tray insertion chamber 1. Tray 1
Reference numeral 4 is a means for holding the substrate. The substrate has a large diameter,
It is a relatively large substrate. Then, the inside of the substrate tray insertion chamber 1 is exhausted with the entrance door 12 and the gate valve 4 closed. When the pressure inside the substrate tray insertion chamber 1 has dropped sufficiently, the gate valve 4 is opened and the tray 14
Is guided by rails (not shown), conveyed in the direction of arrow 15, and fed into the sputtering chamber 2. In the sputtering chamber 2, a thin film is formed by a sputtering method on the surface of the substrate mounted on the tray 14 and in a stationary state by a thin film forming mechanism described later. After forming the thin film, the tray 14 is fed into the substrate tray take-out chamber 3 via the opened gate valve 5. After the tray 14 is transferred to the substrate tray unloading chamber 3, the gate valve 5 is closed and the leak valve 7 is opened.
The substrate mounted on the tray 14 is placed in the atmosphere. Then, the take-out door 13 is opened and the tray 14 is taken out. In the sputtering chamber 2, gas is introduced from a cylinder (not shown) through the gas introduction pipe 16 in the direction of arrow 18a, and is similarly exhausted by an exhaust pump (not shown) through the exhaust port 17 in the direction of arrow 18b. As a result, the sputtering chamber 2 is maintained in a discharge state with the introduced gas flow rate and the exhaust gas flow rate balanced, and a predetermined constant pressure in the range of 10 ^-3 to 10 ^-2 Torr suitable for performing sputtering. Kept in. A substrate heating lamp 19 is arranged on the entrance side of the sputtering chamber 2. The substrate heating lamp 19 is provided as needed. By the heat ray radiation of the substrate heating lamp 19, the temperature of the substrate can be raised before the thin film is formed. A magnetron cathode electrode 20 (hereinafter, referred to as an electrode 20) including a large target having a rectangular flat surface is arranged on the rear side of the sputtering chamber 2 with an insulator 21 interposed therebetween. A target assembly 22 is attached to the upper portion of the electrode 20. In FIG. 1, the upper surface of the target assembly 22 is the target surface. A power supply system 23 including a power supply 24, a power supply line 25 between electrode power supplies, and a power supply earth connection line 26 is connected to the electrode 20, and power is supplied by this configuration.

In the sputtering chamber 2, the tray 14 stands still with respect to the electrode 20, and in this state, the substrate on the tray 14 faces the target surface of the target assembly 22. Sputtered particles flying from the target assembly 22 are deposited on the opposing surface of the substrate to form a thin film on the substrate. In the example in FIG. 1, a combination of one tray 14 and one electrode 20 is shown, but any number of electrodes 20 can be provided in the sputtering chamber 2. The wall of the sputtering chamber 2 has a ground wire 27.
Grounded in.

The structure of the electrode 20 will be described in detail with reference to FIG. The electrode 20 includes an electrode housing 31 and
Magnet assembly 32 disposed inside the electrode housing 31
And the target assembly 22 described above. Three
Reference numeral 3 partially shows the wall of the container forming the sputtering chamber 2. The electrode 20 has an opening 34 formed in the wall 33.
Is attached via the above-mentioned insulator 21. Electrode 20
Is attached to the opening 34 so that the target surface of the target assembly 22 is exposed to the vacuum chamber side. Fixtures for attachment or clamp mechanisms etc. are not shown.

The target assembly 22 includes the target plate 3
5, a target pressing jig 36, and a target back plate 37, which are fixed to the electrode housing 31 by a coupling tool (not shown).

In the concave space 38 formed inside the electrode housing 31, the above-mentioned magnet assembly 32, the link mechanism 40 for supporting the magnet assembly 32, and the magnet assembly and the link mechanism as a whole are concave spaces. A drive unit 41 for moving the inside is incorporated. A drive motor system 42 is attached to the outside of the lower side of the electrode housing 31.

The detailed construction of each of the magnet assembly 32, the link mechanism 40, and the drive section 41 will be described with reference to FIGS. 2 and 3 to 7.

FIG. 3 is a plan view of the magnet assembly 32 as seen from the direction of arrow AA in FIG. Magnet assembly 32
Is a central magnetic pole group 3 arranged along a line located in the center.
2A and an outer peripheral magnetic pole group 32B arranged so as to surround the central magnetic pole group 32A. The central magnetic pole group 32A is configured by arranging a plurality of central unit magnets 61 on a line, and the outer peripheral magnetic pole group 32B is configured by arranging a plurality of outer peripheral unit magnets 71, which are larger than the number of central unit magnets, on a closed curve. Composed.

An external perspective view of the central unit magnet 61 is shown in FIG.
Shown in. As can be seen in this figure, the central unit magnet 6
Reference numeral 1 denotes a permanent magnet 62 disposed on the upper portion, a yoke 63 disposed on the lower portion thereof and fixed with an adhesive, and a magnet fixing plate 6.
It is composed of 4. The permanent magnet 62 is formed of, for example, strontium barium ferrite, and is arranged so that its N pole faces the target side. The yoke 63 is made of, for example, a soft magnetic high magnetic permeability material such as soft iron, is fixed to the surface of the permanent magnet 62 on the S pole side, and has arms 65 formed on both sides. The magnet fixing plate 64 is the central unit magnet 61.
Is a member for fixing to a linear chain described later. The permanent magnet 62 has a required thickness, and its planar shape is a crescent shape in which one side part bulges in a curved line and the other side part on the opposite side is curvedly recessed. Such a shape makes the adjoining relationship between other adjacent central unit magnets in relation to the permanent magnet smooth when moving, without causing any trouble such as contact.

FIG. 6 is an external perspective view of the outer peripheral unit magnet 71.
Shown in. The outer peripheral unit magnet 71 includes a permanent magnet 72 arranged on the upper portion and a yoke 73 bonded to the lower surface of the permanent magnet.
And a magnet fixing plate 74 adhered to the side surface.
The material of the permanent magnet 72 is the same as that of the permanent magnet 62. However, the upper surface of the permanent magnet 72 is arranged so as to have a south pole. The material forming the yoke 73 is the same as that of the yoke 63. Arm 75 provided on the yoke 73
Is provided on only one surface. Arm 7 of the yoke 73
The electrode 5 is attached so as to face the arm 65 of the yoke 63 when assembled to the electrode. The magnet fixing plate 74 is a member for fixing the outer peripheral unit magnet 71 to a revolving chain described later.

In FIG. 3, the central magnetic pole group 32A is, for example, 1
It consists of one central unit magnet 61, and the outer magnetic pole group 32
B consists of, for example, 34 peripheral unit magnets 71. The target side surfaces of all the central unit magnets 61 of the central magnetic pole group are N poles, and the target side surfaces of all the outer peripheral unit magnets 71 of the outer magnetic pole group are S poles. Such an example is an example, and the unit magnets can be made in an arbitrary number and in an arbitrary combination according to the magnetic field lines to be formed.

A link mechanism 40 for moving the magnet assembly 32 will be described with reference to FIG. FIG. 4 is a plan view of the link mechanism as seen from the direction of the arrow of line BB in FIG. The link mechanism 40 is composed of a linear chain 43 and a circulating chain 44. In the linear chain 43,
For example, a TO type crescent chain (trade name; manufactured by Tsubakimoto Chain) is used. This linear chain is provided with a crescent-shaped top plate 45 as indicated by the one-dot chain line. The central unit magnet 61 is the top plate 45.
Is disposed on. Attachments 46 are attached to the orbiting chain 44 at predetermined intervals, and the outer peripheral unit magnets 71 are attached to each of the attachments 46. Linear chain 43 and loop chain 4
The bushes 4 are arranged in substantially the same horizontal plane. A plurality of spacer sprockets 47 are arranged between the linear chain 43 and the orbiting chain 44 to maintain the distance between them at equal intervals. In the illustrated example, two spacer sprockets 47 are illustrated. The number of spacer sprockets should be an appropriate number so that the linear chain 43 and the orbiting chain 44 are not too close to each other and the magnet assembly 32 can be moved while the entire link mechanism is locally deformed. Must be selected for. As shown in FIG. 2, the shaft of the spacer sprocket 47 is fixed to the bush of the linear chain 43 and is configured to be rotatable. This configuration is possible by using a hollow pitch chain as the linear chain.

As shown in FIG. 2, the linear chain 43
An attachment 48 is attached to the lower side of the. The linear chain 43 is fixed to the timing belt 49, which constitutes a part of the drive unit 41 described later as a whole, via the attachment 48. On the other hand, an attachment 50 is provided below the orbiting chain 44, and a moving support plate 51 is fixed to the attachment 50.

With reference to FIGS. 2 and 7, the structure of the drive unit 41 and the positional relationship between the magnet assembly 32 and the drive unit 41 in the concave space 38 in the electrode housing 31 will be described.

Reference numeral 81 is a drive base plate, and the drive base plate 81 is fixed inside the electrode housing 31. The drive base plate 81 supports the link mechanism 40 and assists in smoothly moving the magnet assembly 32. A plurality of guide sprockets 82 are attached to the drive base plate 81 via rotary shafts. Each of the plurality of guide sprockets 82 contacts the bush of the orbiting chain 44 of the link mechanism 40.
The plurality of guide sprockets 82 arranged at predetermined positions as a whole put the magnet assembly 32 on a fixed path through the link mechanism 40 and move it in the concave space 38.

As shown in FIG. 2, the drive base plate 81
A slide ball 83 is embedded in the. On the slide ball 83, the moving support plate 51 below the orbital chain 44 is placed. The slide ball 83 enables smooth movement while supporting the entire magnet assembly and link mechanism.

A plurality of positioning pulleys 84 having a rotating shaft and one drive pulley 85 are mounted on the bottom of the electrode housing. Then, the timing belt 49 is stretched along the outer circumference thereof. The drive pulley 85 is rotated by a drive motor system 42 including a motor 87 fixed to the electrode housing 31 via a support frame 86 and a rotary drive shaft 88 that is axially sealed. As described above, the timing belt 49 is used for the linear chain 4 of the link mechanism 40.
It is fixed to the attachment 48 of No. 3. Therefore, by operating the drive motor system 42, the timing belt 49 can be rotationally moved within the electrode housing. Since the magnet assembly 32 is integrated with the timing belt 49, it moves together with the timing belt 49.

Although not shown, cooling water is introduced into the space 38 from the outside of the electrode housing 31, is brought into contact with the target back plate 37, and is then discharged to the outside. As a result, when discharging is performed, the heat generated on the surface of the target is released to the outside by using the cooling water as a medium. The airtightness between the electrode housing 31 and the target back plate 37 is maintained by an O-ring 91, the airtightness between the electrode 20 and the insulator 21 is maintained by an O-ring 92, and the insulator 21 and the wall portion 33 of the vacuum container are retained. Airtightness is O ring 93
Held by Further, in order to prevent a surface other than the surface to be originally sluttered from the exposed surface on the vacuum side of the target from being subjected to undesired ion bombardment, the shield member 94 is attached to the periphery of the opening portion of the vacuum container wall by a bolt or the like. It is fixed on the inner surface.

The magnetic flux distribution in the magnet assembly 32 will be described with reference to FIGS. 8 and 9. Since the upper surface of the central magnetic pole group 32A is the N pole and the upper surface of the outer peripheral magnetic pole group 32B is the S pole, the outer peripheral magnetic pole group 32 starts from the central magnetic pole group 32A.
Magnetic field lines 100 reaching B are formed. Although only a finite number of magnetic force lines are shown in the illustrated example, it is actually infinite. As a result, on the target surface of the electrode 20, magnetic force lines are emitted from the target surface area corresponding to the target back plate portion facing the upper surface of the central magnetic pole group 32A, enter the surrounding target surface area, and reach the outer magnetic pole group 32B. The magnetic field lines that form form an area of an annular tunnel-like path.
When a negative voltage is applied to the sputtering electrode in this state, electrons are annularly formed on the target surface along a closed tunnel path formed by the magnetic field lines due to the vertical electric field formed on the target surface and the magnetic field of the magnetic field lines. Do a drift exercise. Due to this drift motion, low-voltage and large-current discharge occurs, so that the sputtering film can be produced at a high speed.

The magnet assembly 32 is moved along the arrangement path of the timing belt 49 by the drive motor system 42, the timing belt 49, the link mechanism 40, etc. as described above. In FIG. 10, reference numeral 101 denotes a movement path of the magnet assembly 32 on the drive base plate 81. Magnet assembly 32
Moves clockwise. In the moving path 101, the magnet assembly 32 is deformed according to the form of the moving path. 10
2 to 104 respectively show drift motions of electrons formed by deformation of the tunnel path according to the shape of the magnet assembly.

The velocity of the electron drift motion is very high, and it is estimated that it takes 1 millisecond or less to complete one round of the circular locus in the practical size of the sputtering electrode. On the other hand, the moving speed of the timing belt 49 is relatively slow,
For example, it takes several tens of times per minute at the fastest, so that it takes one second or more at the fastest for the magnet assembly 32 to make one round in the electrode housing and return to the original position.

In the illustrated example of FIG. 10, only three closed trajectories of the drifting electrons 102 to 104 are shown, but in fact, since the magnet assembly 32 is rotationally moved, a continuous infinite number is obtained. Is formed. FIG. 11 shows a region 105 which is subjected to ion bombardment on the target surface and is sputter-etched to contribute to the formation of a thin film. A relatively wide area is effectively used around the movement locus 101 of the center line of the central magnet group 32A.

[0031]

According to the present invention, a thin film can be formed in a stationary state on a rectangular substrate having a relatively large area in a sputtering apparatus. In this case, since the buffer space for translating the substrate is not necessary, the sputtering apparatus itself can be made relatively small. By moving the region where electron drift occurs on the surface of the target and ion bombarding the rectangular target almost entirely, the utilization efficiency of the target is improved, the non-uniformity of target consumption is improved, and it is formed on the substrate. The film quality is uniform and the film thickness is uniform. In addition, the film deposited on the surface of the target is suppressed as the ion bombardment area is expanded, and particles generated due to this film are also suppressed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a sputtering apparatus.

FIG. 2 is a sectional view showing an embodiment of a magnetron cathode electrode according to the present invention.

FIG. 3 is a plan view of a magnet assembly.

FIG. 4 is a plan view of the link mechanism.

FIG. 5 is an external perspective view of a central unit magnet of the central magnetic pole group.

FIG. 6 is an external perspective view of an outer peripheral unit magnet of an outer peripheral magnetic pole group.

FIG. 7 is a plan view showing a configuration of a drive unit and a positional relationship between the magnet assembly and the drive unit in a concave space inside the electrode housing.

FIG. 8 is a cross-sectional view of relevant parts showing a distribution of magnetic force lines between a central magnetic pole group and an outer magnetic pole group.

FIG. 9 is an external perspective view showing a magnetic force line distribution between a central magnetic pole group and an outer magnetic pole group.

FIG. 10 is a plan view showing a movement path of an electron drift generation trajectory on a target surface.

FIG. 11 is a plan view showing a region to be sputter-etched on the target surface.

[Explanation of symbols]

1 Substrate Tray Insertion Chamber 2 Sputtering Chamber 3 Substrate Tray Extraction Chamber 14 Tray 20 Magnetron Cathode Electrode 22 Target Assembly 23 Power Supply System 31 Electrode Housing 32 Magnet Assembly 32A Central Magnetic Pole Group 32B Peripheral Magnetic Pole Group 38 Recessed Space 40 Ring Mechanism 41 Drive Unit 42 Drive motor system 49 Timing belt

Claims (2)

[Claims] 1. A magnetron cathode electrode applied to a sputtering apparatus for forming a thin film, comprising a target having a relatively wide flat surface facing a substrate on which the thin film is formed, wherein the magnetron cathode electrode has an annular tunnel shape near the surface of the target. A magnet assembly that forms a magnetic field distribution, a drive mechanism that moves the magnet assembly along a predetermined trajectory in the space inside the electrode, and a link mechanism that maintains the shape of the magnet assembly and locally deforms the magnet assembly. A magnetron cathode electrode, wherein the magnetic force line distribution is formed according to the form of the magnet assembly, and the magnetic force line distribution moves on the target surface as the magnet assembly moves. 2. The magnetron cathode electrode according to claim 1, wherein the magnet assembly includes a central magnetic pole group in which a plurality of magnets are arranged in a row, and a plurality of magnets arranged so as to surround the central magnetic pole group. A magnetron cathode electrode comprising: