WO2013001715A1

WO2013001715A1 - Sputtering device

Info

Publication number: WO2013001715A1
Application number: PCT/JP2012/003529
Authority: WO
Inventors: 鈴木　英和
Original assignee: キヤノンアネルバ株式会社
Priority date: 2011-06-30
Filing date: 2012-05-30
Publication date: 2013-01-03
Also published as: KR20140027524A; JP5792812B2; JPWO2013001715A1; KR101608603B1; CN103649365B; CN103649365A

Abstract

Provided is a sputtering device that reduces etching speed in readily eroded portions and that has a good utilization efficiency of a target. A rectangular magnetic circuit unit (11) mounted on a magnetron cathode (31) is configured so that the oscillation distance is different between a linear unit (111) composed of a rectangular magnet on the long side portion and an end part unit (112) having a magnet on the short side portion. The oscillation distance of the end part unit (112) is greater than that of the linear unit (111) in the X direction parallel to the target-mounting surface.

Description

Sputtering equipment

The present invention relates to a sputtering apparatus including a magnetron cathode, and more particularly to a sputtering apparatus including a magnetron cathode in which a magnetic circuit unit swings.

There are various cathodes for sputtering equipment. Among these, a magnetron cathode having a magnet on the back side of a flat target is often used. Magnetron cathodes can be classified from two viewpoints: shape and operation of the magnetic circuit unit. Here, the shape of the magnetron cathode is determined by the shape of the target attached to the magnetron cathode, and can be roughly divided into a substantially circular shape and a substantially rectangular shape.

Circular magnetron cathodes are often used for round objects such as semiconductors and magnetic disks. On the other hand, rectangular magnetron cathodes are often used for rectangular objects such as displays and solar cells. From the viewpoint of the operation of the magnetic circuit unit, the magnetic circuit unit is roughly classified into a fixed type and a swinging type. The reason why the magnetic circuit unit is swung is to improve the utilization efficiency of the target and extend its life, and to reduce dust generation from the target by eliminating the non-erosion region.

In the magnetron cathode in which the magnetron cathode is rectangular and the magnetic circuit unit oscillates, the etching speed of the end portion in the long side direction of the magnetron cathode is fast, so there is a problem that the target utilization efficiency is low and the life is short. Various proposals have been made for the issues. As one of the methods, there is a method in which a magnetic shunt having a high magnetic permeability is disposed in a magnet unit, the leakage magnetic flux density at the end portion in the long side direction of the magnetron cathode is lowered, and the etching speed is lowered (for example, Patent Document 1). reference).

JP 2010-1111915 A

However, there is a limit to the method of slowing the etching speed by arranging a magnetic shunt on the magnet unit. This is because magnetron discharge is established by restraining electrons by magnetic force. Lowering the leakage magnetic flux density at the end portion in the long side direction of the magnetron cathode is synonymous with weakening the binding force of electrons at this location. If the leakage magnetic flux density is too low, electrons cannot be restrained, and an endless plasma ring cannot be formed. In other words, the lower limit of the etching speed at the lower limit of the leakage magnetic flux density that can form the magnetron discharge is the limit for improving the utilization efficiency and life of the target by this method.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a sputtering apparatus that slows the etching speed of a portion that is easily eroded and has good target utilization efficiency.

The sputtering apparatus of the present invention includes a vacuum vessel, a substrate holder disposed inside the vacuum vessel and capable of holding a substrate to be film-formed, a target mounting surface capable of mounting a target facing the substrate holder, and A magnetron cathode having a magnetic circuit unit capable of swinging in a first direction parallel to the target mounting surface, the magnetic circuit unit including a first unit having a magnet pair arranged in a direction parallel to the first direction; The second unit has a magnet pair disposed in a direction intersecting the first direction, and the second unit has a longer swing distance than the first unit.

According to the present invention, more uniform erosion can be realized over the entire target. Therefore, it is possible to provide a sputtering apparatus with high target utilization efficiency and a long target life.

Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are denoted by the same reference numerals.

The accompanying drawings are included in the specification, constitute a part thereof, show an embodiment of the present invention, and are used to explain the principle of the present invention together with the description.
It is sectional drawing of the sputtering device provided with the magnetron cathode which concerns on the 1st Embodiment of this invention. It is a top view of the magnetic circuit unit of the magnetron cathode which concerns on the 1st Embodiment of this invention. It is an enlarged view of the magnetic circuit unit of the magnetron cathode which concerns on the 1st Embodiment of this invention. It is a top view which shows the rocking | fluctuation state of the rocking | swiveling apparatus which concerns on the 1st Embodiment of this invention, and a magnetic circuit unit. It is a top view which shows the rocking | fluctuation state of the rocking | swiveling apparatus which concerns on the 1st Embodiment of this invention, and a magnetic circuit unit. It is a top view which shows the rocking | fluctuation state of the rocking | swiveling apparatus which concerns on the 1st Embodiment of this invention, and a magnetic circuit unit. It is a top view which shows the positional relationship of the plasma ring and target which arise with the magnetron cathode in the 1st Embodiment of this invention. It is a top view which shows the positional relationship of the plasma ring and target which arise with the magnetron cathode in the 1st Embodiment of this invention. It is a top view which shows the positional relationship of the plasma ring and target which arise with the magnetron cathode in the 1st Embodiment of this invention. It is sectional drawing which shows the rocking | fluctuation state of the rocking | fluctuation apparatus which concerns on the 2nd Embodiment of this invention, and a magnetic circuit unit. It is sectional drawing which shows the rocking | fluctuation state of the rocking | fluctuation apparatus which concerns on the 2nd Embodiment of this invention, and a magnetic circuit unit. It is sectional drawing which shows the rocking | fluctuation state of the rocking | fluctuation apparatus which concerns on the 2nd Embodiment of this invention, and a magnetic circuit unit. It is a top view showing the shape of erosion when it exists in the center of the rocking | fluctuation range of the X direction of the magnetic circuit unit which concerns on the 2nd Embodiment of this invention. It is a top view showing the shape of erosion when it exists in the left end of the rocking | fluctuation range of the X direction of the magnetic circuit unit which concerns on the 2nd Embodiment of this invention. It is a top view showing the shape of erosion when it exists in the right end of the rocking | fluctuation range of the X direction of the magnetic circuit unit which concerns on the 2nd Embodiment of this invention. It is a figure which shows the result of having simulated the shape of the erosion formed in a target by performing sputtering, rocking | fluctuating the magnetic circuit unit which concerns on the 2nd Embodiment of this invention. It is a top view showing the shape of erosion when it exists in the center of the rocking | fluctuation range of the X direction of the magnetic circuit unit which concerns on a comparative example. It is a top view showing the shape of erosion when it exists in the left end of the operating range of the X direction of the magnetic circuit unit which concerns on a comparative example. It is a top view showing the shape of erosion when it exists in the right end of the operating range of the X direction of the magnetic circuit unit which concerns on a comparative example. It is a figure which shows the result of having simulated the shape of the erosion formed in a target by performing sputtering, rocking | fluctuating the magnetic circuit unit which concerns on a comparative example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this, and various changes can be made without departing from the spirit of the present invention.

(First embodiment)
FIG. 1 is a schematic diagram showing a schematic configuration of a sputtering apparatus provided with a magnetron cathode 1 according to the present invention. As shown in FIG. 1, the sputtering apparatus has a chamber 2, a magnetron cathode 1, and a substrate holder 10 as main components. Further, the sputtering apparatus includes a power source 12 for applying power necessary for the sputtering film forming process to the target back plate 4. A target back plate 4 to which the target 3 is bonded is attached to the chamber 2 (vacuum container) via an insulator 5. The insulator 5 is a member that electrically insulates the chamber 2 and the target back plate 4. The chamber 2, the target back plate 4, and the insulator 5 constitute a processing chamber 6 that can be evacuated.

The target back plate 4 has a target mounting surface to which the target 3 is bonded by bonding. The target mounting surface is formed as a smooth surface facing the substrate holder 10. The target 3 is a film forming material and is bonded to the target mounting surface of the target back plate 4 as described above. A magnetic circuit unit 11 is arranged on the back side of the target back plate 4 (that is, the second surface side of the first surface of the target back plate 4 on the target 3 side and the second surface opposite to the first surface). . Further, on the back side of the target back plate 4, a rocking device for reciprocating the magnetic circuit unit 11 is provided at least in the X direction (first direction) parallel to the target mounting surface. The swing device will be described later with reference to FIG.

A substrate holder 10 that can hold the substrate 9 so as to face the target 3 is provided inside the chamber 2. An exhaust device such as an exhaust pump is connected to the exhaust port 7 of the chamber 2 via a conductance valve (not shown). A gas introduction system 8 having a flow rate controller (MFC) or the like is connected to the chamber 2 as process gas introduction means. Process gas is supplied from the gas introduction system 8 at a predetermined flow rate. As the process gas, for example, a rare gas such as argon (Ar) or a simple substance or a mixed gas containing nitrogen (N 2) can be used.

In the present embodiment, the magnetic circuit unit 11 is disposed on the back side of the target back plate 4 that functions as a vacuum partition, but a partition plate is provided at a position between the target back plate 4 and the magnetic circuit unit 11. The partition plate may be a vacuum partition. The magnetic circuit unit 11 includes, for example, a plate A (A1, A2), a center magnet B (B1, B2), and an outer peripheral magnet C (C1, C2). The magnetron cathode 1 includes, for example, a magnetic circuit unit 11, a swing device, and a target back plate 4.

FIG. 2A is a schematic plan view of the magnetic circuit unit 11 according to the present embodiment, and FIG. 2B is an enlarged view of an end portion (E portion of FIG. 2A) of the magnetic circuit unit 11. On the plate A (A1, A2), a central magnet B (B1, B2) composed of permanent magnets and an outer peripheral magnet C (C1, C2) are arranged apart from each other. It arrange | positions so that the rectangular outer periphery magnet C may surround the axial center magnet B. FIG. The center magnet B and the outer periphery magnet C are magnetized in a direction substantially perpendicular to the paper surface, and the magnetization directions of the center magnet B and the outer periphery magnet C are opposite to each other. For this reason, an endless magnetic tunnel is formed between the center magnet B and the outer peripheral magnet C. The magnetic tunnel is formed on the substrate side of the target mounting surface. More specifically, a stable magnetron discharge is possible by forming a magnetic tunnel on the surface side of the target disposed on the target mounting surface.

When a pair of magnets in which a magnetic tunnel is formed is a magnet pair, the center magnet B1 and the outer peripheral magnet C1 form a magnet pair in the X direction (first direction), and the short side portion of the central magnet B2 and the outer peripheral magnet C2 Forms a magnet pair in the Y direction. Since the outer peripheral magnet C1 is disposed on both sides in the X direction of the central magnet B1, the central magnet B1 forms a magnet pair with the outer peripheral magnet C1 on both sides in the X direction. Here, the short side portion of the outer peripheral magnet C <b> 2 is a short side portion of the rectangular outer peripheral magnet C, and in particular, is a portion of the outer peripheral magnet C <b> 2 located in the longitudinal direction of the center magnet B.

In addition, the shape of the center magnet B and the outer peripheral magnet C is not limited to an axial shape and a rectangular shape. For example, in the outer peripheral magnet C, the shape of the end unit 112 may be a curved shape or a polygon such as a triangle. Moreover, the center magnet B and the outer periphery magnet C can also be comprised by combining many small magnets. In this case, the magnet pair of the center magnet B2 and the outer peripheral magnet C2 has a portion formed in a direction deviating from the Y direction.

Further, the magnetic circuit unit 11 is divided into a straight line unit 111 and an end unit 112 at a position D shown in FIG. The straight line unit 111 (first unit) includes a plate (outer magnet C1) that occupies most of the long side portion of the outer peripheral magnet C and a portion (center magnet B1) that occupies most of the long side portion of the central magnet B. It is arranged on A1. The end unit 112 (second unit) is configured by arranging a short side portion (outer peripheral magnet C2) of the outer peripheral magnet C and a short side portion (central magnet B2) of the central magnet B on the plate A2. .

The short side portions are arranged on both sides in the long side direction of the linear unit 111 (that is, one end side and the other end side of the linear unit 111). The swing direction of the magnetic circuit unit 11 includes the X direction in FIG. Here, the X direction is a direction orthogonal to the long side portion of the rectangular outer peripheral magnet C. The magnetron cathode 1 is configured such that the swing distance of the linear unit 111 and the swing distance of the end unit 112 of the magnetic circuit unit 11 can be set independently.

3 to 5 are plan views illustrating the swinging state of the swinging device and the magnetic circuit unit, and are schematic views of the magnetron cathode 1 as viewed from above the sputtering device. The configuration and operation of the swing device will be described with reference to FIGS. For easy understanding of the position of the magnetic circuit unit 11, the target 3 is indicated by a broken line in FIGS.

FIG. 3 shows the case where the magnetic circuit unit 11 is in the center of the movable range in the X direction.

Nuts

113a and 113b are respectively attached to the linear unit 111 and the end units 112 arranged on both sides thereof, and the linear unit 111 and the end unit 112 are respectively connected to the screw shaft 114a via the

nuts

113a and 113b. , 114b. The

screw shafts

114a and 114b are connected to

motors

115a and 115b, respectively. The

screw shafts

114a and 114b are rotated (forward / reverse) by the

motors

115a and 115b. That is, the nuts 113a and 113b and the

screw shafts

114a and 114b constitute a ball screw mechanism. The straight line unit 111 and the end unit 112 swing in the X direction as the

screw shafts

114a and 114b rotate. Further, since the linear unit 111 and the end unit 112 are driven by

different motors

115a and 115b, the linear unit 111 and the end unit 112 are operated by causing the

motors

115a and 115b to perform different rotational operations. Can be swung at different rocking distances.

4 and 5 show cases where the linear unit 111 and the end unit 112 of the magnetic circuit unit 11 are at the left end and the right end of the movable range in the X direction, respectively. As described above, the linear unit 111 and the end unit 112 can be oscillated at different oscillating distances. Therefore, the oscillating distance of the end unit 112 is set to the oscillating distance of the linear unit 111. It can be longer than that. Further, according to the above-described configuration, the swing distance between the linear unit 111 and the end unit 112 can be simply performed by changing the motor control.

In the above-described embodiment, a mechanism using a ball screw is employed as the swinging device in the X direction. However, since the effect of the present invention does not depend on the specific configuration of the rocking device, other structures can be employed as the rocking device.
As another configuration of the oscillating device, there is only one oscillating power, and an apparatus for changing the gear ratio via a gear in a power transmission path from the motive power to the linear unit 111 and the end unit 112. Can be considered. As another configuration of the oscillating device, the oscillating power is one, and a crank provided on each of the linear unit 111 and the end unit 112 is provided. A device that makes the crank disk different is conceivable. As another configuration of the oscillating device, a configuration using a rack and pinion or an eccentric cam can be considered.

FIGS. 6 to 8 are respectively planes illustrating the position and shape of the plasma ring 14 when the magnetic circuit unit 11 is at the center, the left swing end, and the right swing end of the magnetron cathode 1 in the X direction. FIG. As apparent from FIGS. 10 and 11, the moving distance of the plasma ring in the portion corresponding to the ends arranged on both sides of the straight portion of the magnetron cathode 1 is the moving distance of the plasma ring in the portion corresponding to the straight portion. Longer than that. This is because the moving distance (moving range) of the end unit 112 is larger than the moving distance (moving range) of the linear unit 111. Here, a large moving distance (moving range) means that the moving speed is fast, which contributes to the flattening (uniformization) of the distribution of the etching speed in the moving range. By the movement of the magnetic circuit unit 11, it becomes possible to slow down the etching speed of the target at the end in the long side direction of the magnetron cathode 1, or to flatten (uniformize) the distribution of the etching speed. The use efficiency of the target can be improved and the life can be extended.

As described above, the magnetic circuit unit 11 is composed of a plurality of units, and the distribution range of the plurality of units is individually determined to flatten (uniformize) the distribution of the etching speed of the target. , The utilization efficiency of the target can be improved.

(Second Embodiment)
9 to 11 are cross-sectional views illustrating the swing state of the magnetic circuit unit attached to the magnetron cathode 31 according to the second embodiment. The configuration and operation of the magnetron cathode 31 will be described with reference to FIGS. FIG. 9 shows a case where the magnetic circuit unit 11 (111, 112) is at the center of the movement range in the Y direction. In the following embodiments, members, arrangements, and the like are assigned the same reference numerals as in the first embodiment, and detailed descriptions thereof are omitted.

The magnetron cathode 31 of the present embodiment has an oscillating device (second oscillating device) in the Y direction (see FIG. 9) parallel to the target mounting surface, in addition to the X oscillating device (first oscillating device) described above. This is different from the first embodiment in that it is provided with a device. The Y-direction oscillating device is configured to oscillate the entire X-direction oscillating device that supports the magnetic circuit unit 11 in the Y direction, and includes a support plate 117 that supports the X-direction oscillating device, and a support plate. A ball screw mechanism that swings 117 in the Y direction is provided as a main component. In the present embodiment, the Y direction is orthogonal to the X direction, but is not limited to a configuration in which the Y direction and the X direction are orthogonal.

The support plate 117 is a member that supports the X-direction swing device, and the magnetic circuit unit 11 (111, 112) is attached to the X-direction swing device. The ball screw mechanism has a nut 118 and a screw shaft 119 as main components. The nut 118 is attached to the support plate 117, and the screw shaft 119 and the motor 120 connected to the screw shaft 119 are attached to the chamber 2 side. The screw shaft 119 rotates (forward / reverse) by the power of the motor 120. The support plate 117 connected to the screw shaft 119 via the nut 118 swings in the Y direction as the screw shaft 119 rotates.

According to the film forming apparatus using the magnetron cathode 31 of the present embodiment, it is possible to slow the etching speed of the end portion in the long side direction of the magnetron cathode 31, improving the use efficiency of the target and extending the life. be able to. In the magnetron cathode 31 of this embodiment, the entire magnetic circuit unit 11 also swings in the Y direction, so that the etching speed at the end portion in the long side direction of the cathode is slower than the magnetron cathode 1 of the first embodiment. be able to.

The magnetron cathode 31 of the present embodiment described above is configured such that the entire magnetic circuit unit 11 swings the same distance in the Y direction, and the swinging distances of the linear unit 111 and the end unit 112 differ from each other in the X direction. However, the entire magnetic circuit unit 11 may be swung in the X direction at the same swing distance, and the swing distances of the linear unit 111 and the end unit 112 may be different from each other in the Y direction. In this case, the two end units 112 are arranged separately from the linear unit 111 in the Y direction, and the end unit 112 is larger than the linear unit 111 at the swing end in the Y direction. It can be considered to be a moving configuration. In this case, an X-direction swinging device is connected to the support plate.

(Example)
An example in which the swing distance of the end unit 112 is set to be longer than the swing distance of the linear unit 111 using the magnetron cathode 31 of the second embodiment described above will be described. FIGS. 12, 13 and 14 are plan views showing the shape of the erosion 15 of the target when the magnetic circuit unit 11 is at the center of the operating range in the X direction, the left swing end, and the right swing end, respectively. The erosion shape was simulated from the position of the plasma ring 14. At this time, the erosion was assumed to follow a Gaussian distribution in the cross-sectional direction across the ring of the plasma ring 14.

12-14, the erosion 15 corresponding to the shape of the plasma ring 14 of FIGS. 6-8 is drawn. That is, when the magnetic circuit unit 11 is positioned at the left and right swing ends, the shape of the erosion 15 is obtained under the condition that the end unit 112 is positioned outside the linear unit 111 in the X direction.

FIG. 15 shows the result of simulating the shape of the erosion 16 formed on the target 4 by performing sputtering while swinging the magnetic circuit unit 11. In the simulation of FIG. 15, the rocking distance in the X direction of the magnetic circuit unit 11 is ± 55 mm for the linear unit 111 and ± 70 mm for the end unit 112. The swing distance of the magnetic circuit unit 11 in the Y direction is ± 25 mm. The dimensions of the cathode are 300 mm３００ × 920 mm. In this simulation result, the utilization efficiency of the target 4 was 50.0%. In FIG. 15,

reference numerals

16 a, 16 b, and 16 c are attached according to the depth of the erosion 16. Reference numeral 16c indicates the deepest erosion place. The target utilization rate is a ratio of the amount of the target 3 as a whole when the portion with the deepest erosion reaches the target back plate 4.

(Comparative example)
In this comparative example, a magnetic circuit unit (integrated magnetic circuit unit) that is not divided into the end unit 111 and the linear unit 112 will be described. 16, 17, and 18 are plan views showing the shape of the erosion 18 when the integral magnetic circuit unit is at the center of the X-direction movement range of the magnetron cathode, the left swing end, and the right swing end, respectively. Show. The erosion shape was simulated from the position of the plasma ring 15. At this time, the erosion 18 was assumed to follow a Gaussian distribution in the cross-sectional direction across the ring of the plasma ring 15.

FIG. 19 shows the result of simulating the shape of the erosion 19 formed on the target 4 by performing sputtering while swinging the integrated magnetic circuit unit. In the simulation of FIG. 19, the rocking distance in the X direction of the integral magnetic circuit unit was ± 55 mm, and the rocking distance in the Y direction was ± 25 mm. The dimensions of the cathode are 300 mm３００ × 920 mm. In FIG. 19,

reference numerals

19 a, 19 b and 19 c are attached according to the difference in depth of the erosion 19. Reference numeral 19c indicates a place where the erosion is deepest.

The usage efficiency of target 4 in this simulation was calculated to be 39.9%. Note that the utilization efficiency of the target 4 in the actually measured erosion was 39.3%. The measurement of the utilization efficiency of the target 4 was performed by determining the volume of the measured erosion. Erosion was measured using a three-dimensional measuring instrument equipped with a laser displacement sensor. When comparing the simulation result of FIG. 19 with the simulation result of the embodiment shown in FIG. 15, the embodiment has a smaller difference in erosion depth between the vicinity of the end portion and the straight portion than the comparative example, and the use efficiency of the target is high. I understand that.

The present invention is not limited to the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.

This application claims priority on the basis of Japanese Patent Application No. 2011-145708 filed on June 30, 2011, the entire contents of which are incorporated herein by reference.

X,

Y Oscillation directions

1, 31 Magnetron cathode 2 Chamber 3 Target 4 Target back plate 5 Insulator 6 Processing chamber 7 Exhaust port 8 Gas introduction system 9 Substrate 10 Substrate holder 11 Magnetic circuit unit 12 Power supply 14 Plasma rings 15, 16 18, 19 Erosion A, A1, A2 Plate B, B1, B2 Center magnet C, C1, C2 Outer magnet 111 Linear unit 112

End unit

113a, 113b, 118

Nut

114a, 114b, 119

Screw shaft

115a, 115b, 120 Motor 117 support plate

Claims

A vacuum vessel;
A substrate holder disposed inside the vacuum vessel and capable of holding a substrate to be film-formed;
A target mounting surface capable of mounting a target facing the substrate holder, and a magnetron cathode having a magnetic circuit unit swingable in a first direction parallel to the target mounting surface,
The magnetic circuit unit includes a first unit having a magnet pair arranged in a direction parallel to the first direction, and a second unit having a magnet pair arranged in a direction intersecting the first direction,
The sputtering apparatus according to claim 1, wherein the second unit has a longer swing distance than the first unit.
The magnetic circuit unit includes two rectangular outer magnets and a central magnet disposed between the two outer magnets,
The first direction is a direction orthogonal to the long side direction of the rectangle of the two outer peripheral magnets and parallel to the target mounting surface,
The sputtering apparatus according to claim 1, wherein the second unit constitutes the rectangular short side portion of the outer peripheral magnet.
3. The sputtering apparatus according to claim 1, wherein a swing distance of the second unit in the first direction is longer than a swing distance of the first unit in the first direction.
The sputtering apparatus according to any one of claims 1 to 3, wherein the magnetic circuit unit can swing in a second direction orthogonal to the first direction.
A vacuum vessel;
A substrate holder for holding a substrate inside the vacuum vessel;
A target mounting surface to which a target can be mounted facing the substrate holder, and a magnetron cathode having a swingable magnetic circuit unit,
The magnetic circuit unit includes a first unit having a magnet pair and a second unit having a magnet pair;
A sputtering apparatus, wherein a swing range of the first unit and a swing range of the second unit are different from each other.