JP2005008918A - Cathode for magnetron sputtering equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cathode for magnetron sputtering equipment which can increase use efficiency of a target and make the production conditions for the cathode clear. <P>SOLUTION: The cathode for the magnetron sputtering equipment is equipped with the target 1 comprising a target material 2 and a backing plate 3 which supports the target material 2 from its back and a magnetic circuit 5 which is located on the back of a backing plate 3 and forms a magnetic field on the surface of the target material 2. Within the magnetic field distribution at the surface of the target material 2, a magnetic field-controlling member 4 made of a soft magnetic material is installed only at the position of the backing plate 3 which faces the region wherein a component perpendicular to the target 1 becomes 0. <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.
As shown in FIG. 10, such a cathode is generally disposed on the back side of the target material 12 and a target 11 consisting of a backing plate 13 that supports the target material 12 from the back side, and the backing plate 13. A magnetic circuit 14 for forming a magnetic field on the surface of the target material is provided.
[0003]
In the above configuration, when a voltage is applied to the target 11 in a state where the target material 12 is opposed to the main surface of a deposition target substrate (not shown), and the Ar space is introduced with these arrangement spaces under vacuum. The Ar gas is ionized by the electrons emitted from the target material 12, and the ionized Ar gas collides with the surface of the target material 12 and the erosion 20 is advanced, and the target material is knocked out and knocked out. The target material deposited on the main surface of the substrate forms a thin film. At this time, the magnetic field 21 leaking to the surface of the target material 12 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]
The magnetic field distribution on the surface of the target material 12 in such a conventional cathode for a magnetron sputtering apparatus is shown in the graph of FIG.
FIG. 11 is directed to the right half region from the center of the conventional cathode, and the magnetic flux density on the surface of the target material 12 is perpendicular to the component parallel to the target 11 (shown by the solid line in FIG. 11) (FIG. 11). 11 (shown by broken lines 11).
However, such a configuration of the cathode for the magnetron sputtering apparatus has an advantage that film formation can be performed at high speed, but only a part of the surface of the target material 12 is concentrated and sputtered. As shown in FIG. 12, the deepest portion 20 a tends to be a sharp V-shape, so that there is a problem that the usage efficiency of the target material 12 is extremely small.
[0005]
In order to solve this problem, a magnetic plate is provided on the backing plate corresponding to each of the magnetic poles and the magnetic poles in the magnetic circuit disposed on the back side of the target, and a portion corresponding to the gap between the magnetic poles on the backing plate is provided. There has been proposed a structure in which a plurality of voids or high magnetic resistance portions are formed so that a portion having a strong parallel magnetic field on the surface side of the target material is expanded (see Patent Document 1).
[0006]
[Patent Document 1]
Japanese Examined Patent Publication No. 3-62789 (page 3, FIGS. 1 and 6)
[0007]
[Problems to be solved by the invention]
However, the proposed cathode has an effect that the cross-sectional shape of the erosion formed on the surface of the target material is made relatively uniform, but a plurality of voids (high magnetoresistive portions) are formed at portions corresponding to the magnetic poles. The location of the magnetic plates to be formed is unclear, and unless the location of the magnetic plates is set strictly, the erosion cross-sectional shape is changed to the desired shape by widening the portion where the above-mentioned parallel magnetic field is strong. There is no guarantee that the usage efficiency of the target material will not be changed and therefore the usage efficiency of the target material will be increased.
[0008]
In light of such circumstances, an object of the present invention is to provide a cathode for a magnetron sputtering apparatus in which the manufacturing setting conditions are clear and the usage efficiency of the target can be reliably increased.
[0009]
[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 the target material backing plate is limited to the position directly facing the region where the component perpendicular to the target is 0 in the magnetic field distribution on the surface of the target material. It has been found that by arranging a magnetic field control member made of a soft magnetic material, local progress in the deepest part of erosion can be suppressed, and the present invention has been completed.
[0010]
The present invention comprises a target comprising a target material and a backing plate for supporting the target material from the back side, and a magnetic circuit disposed on the back side of the backing plate and forming a magnetic field on the surface of the target material. In the magnetron sputtering apparatus cathode, a soft magnetic force that reduces the magnetic field strength in the region only at the position of the backing plate that faces the region where the component perpendicular to the target becomes 0 in the magnetic field distribution on the surface of the target material. The present invention relates to a cathode for a magnetron sputtering apparatus, wherein a magnetic field control member made of a magnetic material is provided.
[0011]
In this cathode for a magnetron sputtering apparatus, a target is formed by a magnetic field control member made of a soft magnetic material provided on the backing plate at a position facing a region where a component perpendicular to the target becomes 0 in the magnetic field distribution on the surface of the target material. The magnetic field strength in the region on the surface of the material is reduced. Thereby, the progress of the deepest part of the erosion formed on the surface of the target material by sputtering is suppressed, and the region to be sputtered is widened, and the use efficiency of the target material is enhanced.
In particular, since the position of the magnetic field control member made of the soft magnetic material on the backing plate is clearly limited to a position facing the region where the vertical component is 0, the erosion shape is changed to a desired shape. As a result, the use efficiency of the target material is reliably ensured.
[0012]
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.
In FIG. 1, the cathode for the magnetron sputtering apparatus is disposed on the back side of the target 1, which includes a target material 2 and a backing plate 3 that supports the target material 2 from the back side, and the target A magnetic circuit 5 for forming a magnetic field on the surface of the material 1 is provided.
[0013]
A magnetic field control member 4 made of a soft magnetic material is disposed on the backing plate 3 only at a position facing a region where the component perpendicular to the target 1 becomes 0 in the magnetic field distribution on the surface of the target material 2. ing.
The magnetic field control member 4 reduces the magnetic field strength in the region leaking to the surface of the target material in order to suppress the progress of the deepest part of the erosion 8 formed on the surface of the target material 2 by sputtering. Function.
Here, the soft magnetic material constituting the magnetic field control member 4 is not particularly limited, and pure iron, permalloy, silicon iron, stainless steel, and the like can be used.
[0014]
The magnetic field distribution in this type of cathode is generally such that the magnetic field component perpendicular to the target 1 is about 40 mm from the center of the target 1.
Therefore, as shown in FIG. 2, the magnetic field control member 4 has an arrangement structure of SUS430 stainless steel having a width of 20 mm and a thickness of 2 mm as the magnetic field control member 4 with the center at a position of 40 mm from the center of the target 1. A plate-like body made of is embedded in the backing plate 3.
[0015]
Specifically, the magnetic field control member 4 is inserted into the recess 3 a formed in the packing plate 3, and the nonmagnetic material member 7 is overlaid on the magnetic field control member 4 with the screws 9 made of a nonmagnetic material. The magnetic field control member 4 is fastened and fixed to the bottom surface of the recess 3a via the nonmagnetic member 7.
Of course, the mounting structure of the magnetic field control member 4 is not limited to the above configuration, and as shown in FIG. 3, the magnetic field control member 4 is screwed or adhered to the front surface or the back surface of the backing plate 3. It may be fixed.
[0016]
The position in the height direction of the magnetic field control member 4, that is, the distance from the target material 2 is not particularly defined, and is correct in the region where the component perpendicular to the target 1 is 0 in the magnetic field distribution. However, as the arrangement position is closer to the target material 2, the influence on the leakage magnetic field distribution on the surface of the target material 2 becomes larger, which is more effective.
The magnetic field control member 4 is arranged in a circular shape around the center of the backing plate 3 in a circular cathode as shown in FIG. 6, and is arranged in a rectangular shape around the center of the backing plate 3 in a rectangular cathode shown in FIG. 7. Is done.
[0017]
In the above-described configuration, an arrangement space of the target material 2 facing the main surface of the substrate to be formed is set under vacuum, and Ar gas is introduced into this space. When a voltage is applied to the target 1 in this state, Ar gas is ionized by electrons emitted from the target material 2. The ionized Ar gas collides with the target material 2 to knock out the target material while forming the erosion 8, and deposits the knocked target material on the main surface of the substrate to form a thin film. At this time, the magnetic field leaking to the surface of the target material 2 is concentrated in a region orthogonal to the electric field, and high-density plasma is generated, whereby film formation is performed at high speed.
[0018]
Here, in the magnetic field distribution on the surface of the target material 2, the magnetic field control member 4 made of a soft magnetic material is disposed on the backing plate 3 at a position facing a region where the component perpendicular to the target 1 is 0. Local progress in the deepest part of erosion 8 is suppressed. For this reason, the sputter | spatter area | region (width | variety) in the target material 2 spreads, the local advance of the erosion 8 is suppressed by that much, and the use efficiency of the target material 2 improves as a result.
In addition, in this case, the magnetic field control member 4 is specified at a position facing the region where the component perpendicular to the target 1 is 0 in the magnetic field distribution on the surface of the target material 2 in the backing plate 3. The arrangement position of the control member 4 becomes clear. In other words, the manufacturing condition is accurately set, the desired cross-sectional shape of the erosion can be obtained, and the use efficiency of the target material 2 can be reliably ensured.
[0019]
【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 surface of the target material demonstrated below, it is only one side from the center of a target, and a horizontal component (indicated by a solid line) and a vertical component (indicated by a broken line) of the target The graph is displayed separately.
[0020]
Example 1
The magnetic field control member 4 made of SUS430 stainless steel having a width of 20 mm and a thickness of 2 mm shown in the embodiment is positioned at a position 40 mm from the center of the target 1, that is, in the magnetic field distribution on the surface of the target material 2. A cathode for a magnetron sputtering apparatus having the configuration of the embodiment shown in FIG. 1 was manufactured by being embedded in the backing plate 3 at a position facing the position 40 mm from the center where the component perpendicular to the target 1 becomes zero.
[0021]
When the magnetic flux density distribution on the surface of the target material 2 in the cathode for the magnetron sputtering apparatus was measured, as shown in FIG. 4, both the region having a strong parallel component and the region having a vertical component close to 0 expanded.
Using the manufactured cathode, the target material 2 was sputtered, and the use efficiency of the target material 2 was evaluated from the cross-sectional shape.
In this example, as a result of sputtering the target material 2, the erosion 8 has a cross-sectional shape as shown in FIG. That is, the deepest part 8a is shallower than the cross-sectional shape of the conventional erosion, and the whole becomes a gentle shape, and the width of the erosion 8 is increased. The use efficiency of the target material 2 was as high as 35%.
[0022]
Comparative Example 1
With respect to the conventional cathode for a magnetron sputtering apparatus having the magnetic field distribution shown in FIG. 11, the magnetic field control member 4 made of SUS430 stainless steel having a width of 20 mm and a thickness of 2 mm is 25 mm from the center of the target 11. It was embedded in the backing plate 13 around the position, that is, the position that does not face the position 40 mm from the center where the component perpendicular to the target 11 becomes 0 in the magnetic field distribution on the surface of the target material 12.
[0023]
Sputtering was performed using such a cathode, and the magnetic field distribution on the surface of the target material 12 and the cross-sectional shape of the erosion 20 after sputtering were measured.
In the magnetic field distribution, as shown in FIG. 8, the parallel component near 20 mm from the center greatly decreased. Further, the obtained erosion 20 had a cross-sectional shape as shown in FIG. 9, and the vicinity of the deepest portion 20a became a steep substantially V shape, and the erosion width was reduced. The use efficiency of the target material 12 was as low as 18%.
[0024]
【The invention's effect】
As described above, according to the present invention, in the backing plate, a magnetic field control member made of a soft magnetic material only at a position facing a region where the component perpendicular to the target is 0 in the magnetic field distribution on the surface of the target material. Therefore, the progress of the deepest part of the erosion formed on the surface of the target material by sputtering can be suppressed, the area to be sputtered can be widened, and the use efficiency of the target material can be improved. Since the position of the body on the backing plate is specified and clarified, it can be ensured that the intended purpose is achieved.
[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 cross-sectional view showing an example of a structure for attaching a magnetic field control member.
FIG. 3 is a cross-sectional view showing another example of the attachment structure of the magnetic field control member.
FIG. 4 is a graph showing the magnetic field distribution on the surface of the target material of the cathode for the magnetron sputtering apparatus.
FIG. 5 is a diagram showing a cross-sectional shape of erosion formed on the surface of a target material when sputtering is performed using a cathode for a magnetron sputtering apparatus.
FIG. 6 is a partially broken perspective view showing an application mode of a cathode for a magnetron sputtering apparatus of the present invention to a circular cathode.
FIG. 7 is a partially broken perspective view showing an application mode of a cathode for a magnetron sputtering apparatus of the present invention to a rectangular cathode.
8 is a graph showing a magnetic field distribution on the surface of a target material of a cathode for a magnetron sputtering apparatus in Comparative Example 1. FIG.
FIG. 9 is a diagram showing a cross-sectional shape of erosion formed on the surface of a target material when sputtering is performed using the cathode for the magnetron sputtering apparatus in Comparative Example 1;
FIG. 10 is a front sectional view showing a conventional cathode for a magnetron sputtering apparatus.
FIG. 11 is a graph showing a magnetic field distribution on a target material surface of a cathode for a conventional magnetron sputtering apparatus.
FIG. 12 is a diagram showing a cross-sectional shape of erosion formed on the surface of a target material when sputtering is performed using a conventional cathode for a magnetron sputtering apparatus.
[Explanation of symbols]
1 Target 2 Target Material 3 Backing Plate 4 Magnetic Field Control Member 5 Magnetic Circuit

Claims (1)

Magnetron sputtering apparatus comprising: a target comprising a target material and a backing plate for supporting the target material from the back side; and a magnetic circuit disposed on the back side of the backing plate for forming a magnetic field on the surface of the target material In the cathode for
A magnetic field control member made of a soft magnetic material that reduces the magnetic field strength in the region only at the position of the backing plate facing the region where the component perpendicular to the target becomes 0 in the magnetic field distribution on the surface of the target material. A cathode for a magnetron sputtering apparatus characterized by being arranged.

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