JP2005008917A - Cathode for magnetron sputtering equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily produce a cathode for magnetron sputtering equipment which can increase use efficiency of a target without increasing size or cost. <P>SOLUTION: The cathode for the magnetron sputtering equipment has a magnetic circuit A located on the back of the target 14. The magnetic circuit A is composed of an inner magnetic pole 11, an outer magnetic pole 12 which has a polarity opposite of that of the inner magnetic pole 11 and surrounds the inner magnetic pole 11 and a yoke 13 which comprises a plate made of a magnetic material and magnetically connects the inner and outer magnetic poles 11 and 12. A magnetic field-controlling member 17 made of a soft magnetic material is supported on the main side of the yoke 13 via a non-magnetic member 18 and is placed between the inner and outer magnetic poles 11 and 12 in the area facing the deepest part 80a of an erosion 80 formed on the target 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cathode for a magnetron sputtering apparatus used in a process of forming a transparent electrode film in a liquid crystal display, an OLDE, a solar cell and the like by a sputtering method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a means for forming a transparent electrode film on a transparent substrate for a liquid crystal display, for example, a cathode for a magnetron sputtering apparatus that performs sputtering by forming a high density plasma by a magnetic field leaking to the target surface side is known.
In general, as shown in FIG. 9, such a cathode is magnetically composed of an inner magnetic pole 1 and an outer magnetic pole 2 that is opposite to the inner magnetic pole 1 and surrounds the inner magnetic pole 1 by a yoke 3 made of a plate-like magnetic material. The magnetic circuit A that is connected to the housing and accommodated in the case 6 is arranged on the back side of the target support member (backing plate) 5 that supports the target 4 from the back side.
[0003]
In the above configuration, when a voltage is applied to the target 4 in a state where the target 4 is opposed to the main surface of the deposition target substrate (not shown), Ar gas is introduced with these arrangement spaces under vacuum, Ar gas is ionized by electrons emitted from the target 4, and the ionized Ar gas collides with the surface of the target 4 to form an erosion 8, and the target material is knocked out and knocked out. A thin film is formed by depositing a substance on the main surface of the substrate. At this time, the magnetic field 7 leaking to the surface of the target 4 is concentrated in a region orthogonal to the electric field, and high-density plasma is generated, whereby film formation on the main surface of the substrate is performed at high speed.
[0004]
However, although the conventional configuration has an advantage that film formation can be performed at high speed, only a part of the surface of the target 4 is sputtered in a concentrated manner, so that the cross-sectional shape of the erosion 8 is a tight V-shape. There is a problem that the shape tends to become a shape, and therefore the use efficiency of the target material is extremely small.
For this reason, in order to suppress local progress of the erosion 8, a technique has been proposed in which the magnetic circuit A on the back side of the target 4 is moved in the direction between the magnetic poles 1 and 2 (inside and outside). In that case, the entire structure of the cathode is complicated and large, which increases manufacturing costs, and there are still new issues such as fluctuations in film formation distribution and rate with the movement of the magnetic field. There are many problems.
[0005]
A technique of embedding a magnetic material on the target support plate 5 side, between the inner magnetic pole and the outer magnetic pole, in order to suppress local progress of erosion without incurring enlargement of the cathode. Has been proposed (Patent Document 1). However, in this technique, it takes time to embed the magnetic material in the target support plate.
[0006]
[Patent Document 1]
Japanese Examined Patent Publication No. 3-62789 (page 3, FIG. 1, FIG. 6).
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION In light of such circumstances, the present invention has an object to provide a cathode for a magnetron sputtering apparatus that can increase the use efficiency of a target without increasing the size and cost, and making it easy to manufacture. .
[0008]
[Means for Solving the Problems]
As a result of intensive studies on the cathode for the magnetron sputtering apparatus, the present inventors have found that a soft magnetic material is placed between the inner magnetic pole and the outer magnetic pole, and a nonmagnetic material member is placed in a region facing the deepest part of the target erosion. It is found that the strength at the deepest part of the magnetic field leaking to the target surface can be locally reduced by providing it on the yoke, thereby making it relatively easy to suppress the local progression of erosion. Thus, the present invention has been completed.
[0009]
According to the present invention, a magnetic circuit configured by magnetically connecting an inner magnetic pole and an outer magnetic pole surrounding the inner magnetic pole with a polarity opposite to the inner magnetic pole by a yoke made of a plate-like magnetic material is provided on the back surface of the target. In the magnetron sputtering apparatus cathode disposed on the side, the deepest part of the magnetic field leaking to the target surface is located between the inner magnetic pole and the outer magnetic pole and in a region facing the deepest part of the erosion formed on the target. A cathode for a magnetron sputtering apparatus, characterized in that a magnetic field control member made of a soft magnetic material that locally lowers the strength of the magnet is disposed and supported on the main surface side of the yoke via a non-magnetic material member It is related to.
[0010]
In the cathode for the magnetron sputtering apparatus, the deepest magnetic field leaking to the target surface is formed by a magnetic field control member disposed between the inner magnetic pole and the outer magnetic pole and facing the deepest portion of the erosion formed on the target. As a result, the strength at the site is locally reduced, and as a result, the sputtered width is widened, local progress of erosion is suppressed, the use efficiency of the target can be improved, and the magnetic circuit is moved. Thus, the structure is simple and the cost can be reduced.
In particular, since the magnetic field control member is supported by the yoke via the non-magnetic member, the manufacture becomes easier as compared with the case where the magnetic field control member is embedded in the target support plate.
[0011]
According to another aspect of the present invention, there is provided a magnetic circuit configured by magnetically connecting an inner magnetic pole and an outer magnetic pole surrounding the inner magnetic pole with a polarity opposite to the inner magnetic pole by a yoke made of a plate-like magnetic material. Is disposed on the back side of the target, and the magnetic field leaks to the target surface in the region between the inner magnetic pole and the outer magnetic pole and facing the deepest part of the erosion formed on the target. A permanent magnet as a magnetic field control member that locally lowers the strength of the deepest portion of the magnet, and supports the permanent magnet on the main surface side of the yoke via a non-magnetic member, and the magnetization direction of the permanent magnet Are set so as to be perpendicular to the magnetization directions of the inner magnetic pole and the outer magnetic pole and to have a forward direction in which no repulsive magnetic field is generated between the different magnetic poles. Those of the cathode Nsupatta device.
[0012]
In the cathode for the magnetron sputtering apparatus, the magnetic field control member disposed between the inner magnetic pole and the outer magnetic pole and facing the deepest part of the erosion formed on the target is a permanent magnet, so that it leaks to the target surface. The reduction in the strength of the magnetic field in the region is increased, and as a result, the sputtered width is further increased.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a front sectional view showing an example of a cathode for a magnetron sputtering apparatus of the present invention.
[0014]
In FIG. 1, inside a case 16 having a U-shaped cross-section, an inner magnetic pole 11 and an outer magnetic pole 12 having a polarity opposite to the inner magnetic pole 11 and surrounding the inner magnetic pole 11 are provided with a yoke 13 made of a plate-like magnetic material. The magnetic circuit A configured to be magnetically connected is housed. The case 16 has a circular planar shape, for example, and is made of a nonmagnetic material such as SUS304.
A target 14 is disposed to face the main surface of a film formation substrate (not shown), and this target 14 is supported by a target support plate (backing plate) 15 from the back. The magnetic circuit A is arranged on the back side of the target 14 (specifically, the back side of the target support plate 15).
[0015]
Between the inner magnetic pole 11 and the outer magnetic pole 12, it faces the deepest part of the erosion 80 in the target 14 shown in FIG. 4 (part where the component perpendicular to the target 14 is 0 in the magnetic field distribution) 80 a. A magnetic field control member 17 made of a soft magnetic material is disposed in the region, and this magnetic field control member 17 is for locally reducing the strength of the magnetic field leaking to the surface of the target 14 at the deepest portion. And is supported on the main surface side of the yoke 13 via a non-magnetic member 18.
[0016]
The soft magnetic material constituting the magnetic field control member 17 is not particularly limited, but SUS430 is preferably used from the viewpoint of corrosion resistance. The constituent material of the nonmagnetic member 18 is not particularly limited, and a metal material such as aluminum, copper, nonmagnetic stainless steel such as SUS304, or a synthetic resin material can be used.
Examples of a method for fixing the nonmagnetic member 18 to the yoke 13 include bonding or a method of fastening with a screw made of a nonmagnetic material such as brass or SUS.
[0017]
Here, the arrangement position of the magnetic field control member 17 will be described.
In general, when sputtering is performed using a cathode for a magnetron sputtering apparatus, an erosion having a substantially V-shaped cross section is formed in a ring shape for a circular cathode and in a track shape for a rectangular cathode.
Therefore, in the embodiment of the present invention, as described above, the magnetic field control member 17 is disposed in a region facing the deepest portion 80a of the erosion 80. In addition, the area | region which directly faces here shows the area | region where the deepest part 80a of the said erosion 80 exists in the width range of the magnetic field control member 17. FIG.
[0018]
In the above configuration, the space for arranging the target 14 facing the main surface of the substrate to be deposited is set under vacuum, and Ar gas is introduced into this space. When a voltage is applied to the target 14 in this state, Ar gas is ionized by electrons emitted from the target 14. The ionized Ar gas collides with the target 14 and the target material is knocked out while the erosion 80 is progressively formed. The knocked target material is deposited on the main surface of the substrate, thereby forming a thin film. At this time, a magnetic field leaking to the target surface is concentrated in a region orthogonal to the electric field, and high-density plasma is generated, whereby film formation is performed at high speed.
[0019]
Here, since the magnetic field control member 17 is disposed between the inner magnetic pole 11 and the outer magnetic pole 11 in a region facing the deepest portion 80a of the erosion 80 in the target 14, the magnetic field leaking to the surface of the target 14 is reduced. The strength at the deepest site is locally reduced. For this reason, the sputter | spatter area | region (width | variety) in the target 14 spreads, the local advance of the erosion 80 is suppressed correspondingly, and the use efficiency of the target 14 is improved as a result.
In addition, in this case, since the magnetic circuit A is not moved, the structure is simple, the miniaturization of the apparatus can be maintained, and the manufacturing cost can be reduced. In particular, since the magnetic field control member 17 is supported by the yoke 13 via the non-magnetic member 18, there is an advantage that the magnetic field control member 17 is easier to make than a structure in which the magnetic field control member 17 is embedded in the target support plate 15. .
[0020]
Next, another embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a front sectional view showing another example of the cathode for a magnetron sputtering apparatus of the present invention. The same or corresponding parts as those in FIG.
In FIG. 2, between the inner magnetic pole 11 and the outer magnetic pole 12, on the main surface side of the yoke 13, the deepest part of the erosion 80 formed on the target 14 (the component perpendicular to the target 14 in the magnetic field distribution). The magnetic field control member 19 made of a permanent magnet is supported via a non-magnetic member 18 in a region directly facing 80a.
[0021]
Further, the magnetic field control member 19 made of the permanent magnet is set so that its magnetization direction 100 is in a direction perpendicular to the magnetization direction 101 of the inner magnetic pole 11 and the magnetization direction 102 of the outer magnetic pole 12 and forward. Has been.
For example, in FIG. 2, in the case where the upper surface of the inner magnetic pole 11 (target 14 side) is set as an N pole, the magnetization direction of the magnetic field control part material 19 is an S pole on the inner side and an N pole on the outer side. It is set to be That is, N pole-S pole-N pole-S pole as viewed from the target 14 side are arranged in an order in which a repulsive magnetic field does not occur between the magnetic poles 11 and 12.
[0022]
By configuring in this way, the region of the magnetic field component parallel to the surface of the target 14 can be expanded, and the region to be sputtered on the surface of the target 14 can be further expanded.
The cathode shape shown in FIG. 2 is also the same circle as that shown in FIG. 1, but the cathode shape of the present invention is not limited to a circle and can be applied to a rectangle.
[0023]
【Example】
Next, examples of the present invention will be specifically described, but the present invention is not limited to the following examples.
In addition, about the measurement result of the magnetic flux density distribution of the target surface described below, the graph is divided into a component (indicated by a solid line) and a component (indicated by a broken line) that are horizontal to the target only on one side from the center of the target. It is displayed.
[0024]
Comparative Example 1
The cathode for the conventional magnetron sputtering apparatus shown in FIG. 9 was produced. FIG. 7 shows the magnetic flux density of the target surface in this cathode.
Using a cathode having such a magnetic field distribution, a copper target having a thickness of 6 mm was sputtered until the deepest part of erosion was 5 mm.
The obtained erosion 8 had a substantially V-shaped cross section as shown in FIG. 8, and the use efficiency was as low as 20%. Further, the position of the deepest portion 8a of the erosion 8 was about 40 mm from the center, and coincided with the position where the vertical component in FIG.
[0025]
Example 1
A magnetic field control member 17 made of SUS430 is disposed between the inner magnetic pole 11 and the outer magnetic pole 12 in a region facing the deepest portion 80a of the erosion 80 in the target 14 via a nonmagnetic member 18 made of aluminum. By attaching to 13, a cathode for a magnetron sputtering apparatus according to the configuration of the first embodiment was produced.
When the magnetic flux density distribution on the target surface in the cathode for the magnetron sputtering apparatus was measured, as shown in FIG. 3, the horizontal magnetic field component in the vicinity of 40 mm slightly decreased, and the inclination of the horizontal magnetic field component gradually changed.
[0026]
As a result of sputtering a copper target having a thickness of 6 mm as in Comparative Example 1 using the manufactured cathode, the erosion 80 had a cross-sectional shape as shown in FIG. That is, it was confirmed that the width of the erosion 80 was enlarged and the shape in the vicinity of the deepest portion 80a was gently changed. The target usage efficiency was as high as 30%.
[0027]
Example 2
By replacing the magnetic field control member 17 in the configuration of Example 1 with the permanent magnet 19, a cathode for a magnetron sputtering apparatus according to the configuration in the second embodiment was manufactured.
Similarly, when the magnetic flux density distribution on the target surface in the cathode for the magnetron sputtering apparatus was measured, the result shown in FIG. 5 was obtained. The horizontal magnetic flux density in the region corresponding to the magnetic field control member 19 made of a permanent magnet was greatly reduced to form an M shape. Also, the vertical component was greatly inclined around 0 Tesla.
[0028]
As in Example 1, as a result of sputtering the copper target, the erosion 80 had a cross-sectional shape as shown in FIG.
As compared with Example 1, it was confirmed that the width of the erosion 80 was further expanded, and the shape in the vicinity of the deepest portion was also changed to a substantially U shape. The usage efficiency of the target was remarkably high at 37%.
[0029]
【The invention's effect】
As described above, according to the first aspect of the present invention, the magnetic field control member supported by the yoke via the non-magnetic member is disposed in the region facing the deepest part of the erosion of the target. In addition, local progress of erosion can be suppressed without incurring high cost and high target usage efficiency can be achieved with ease.
According to a second aspect of the present invention, a permanent magnet having a specified magnetization direction is disposed as a magnetic field control member supported by a yoke via a nonmagnetic member in a region facing the deepest part of the target erosion. With this configuration, local progress of erosion can be further suppressed.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a cathode for a magnetron sputtering apparatus according to an embodiment of the present invention.
FIG. 2 is a front sectional view showing a cathode for a magnetron sputtering apparatus according to another embodiment of the present invention.
3 is a graph showing the magnetic field distribution on the target surface of the cathode for the magnetron sputtering apparatus of FIG. 1. FIG.
4 is a diagram showing a cross-sectional shape of erosion formed on a target surface when sputtering is performed using the cathode for the magnetron sputtering apparatus of FIG. 1. FIG.
5 is a graph showing the magnetic field distribution on the target surface of the cathode for the magnetron sputtering apparatus of FIG.
6 is a diagram showing a cross-sectional shape of erosion formed on the surface of a target when sputtering is performed using the cathode for the magnetron sputtering apparatus of FIG. 2. FIG.
FIG. 7 is a graph showing a magnetic field distribution on a target surface of a cathode for a conventional magnetron sputtering apparatus.
FIG. 8 is a diagram showing a cross-sectional shape of erosion formed on a target surface when sputtering is performed using a conventional cathode for a magnetron sputtering apparatus.
FIG. 9 is a front sectional view showing a conventional cathode for a magnetron sputtering apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Inner magnetic pole 12 Outer magnetic pole 13 Yoke 14 Targets 17 and 19 Magnetic field control member 18 Nonmagnetic material member 80 Erosion 80a Deepest part A Magnetic circuit

Claims (2)

A magnetic circuit configured by magnetically connecting an inner magnetic pole and an outer magnetic pole surrounding the inner magnetic pole with a polarity opposite to the inner magnetic pole by a yoke made of a plate-like magnetic material is provided on the back side of the target. In the cathode for magnetron sputtering apparatus arranged,
From the soft magnetic material that locally decreases the strength of the magnetic field leaking to the target surface at the deepest portion between the inner magnetic pole and the outer magnetic pole and facing the deepest portion of the erosion formed on the target. A cathode for a magnetron sputtering apparatus, characterized in that a magnetic field control member is provided and supported on the main surface side of the yoke via a non-magnetic member. A magnetic circuit configured by magnetically connecting an inner magnetic pole and an outer magnetic pole surrounding the inner magnetic pole with a polarity opposite to the inner magnetic pole by a yoke made of a plate-like magnetic material is provided on the back side of the target. In the cathode for magnetron sputtering apparatus arranged,
As a magnetic field control member for locally reducing the strength at the deepest part of the magnetic field leaking to the target surface in a region between the inner magnetic pole and the outer magnetic pole and facing the deepest part of the erosion formed on the target. A permanent magnet is supported on the main surface side of the yoke via a non-magnetic member,
A cathode for a magnetron sputtering apparatus, wherein the magnetization direction of the permanent magnet is set to be perpendicular to the magnetization directions of the inner magnetic pole and the outer magnetic pole and to be a forward direction in which no repulsive magnetic field is generated between different magnetic poles. .

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