JPH07300669A - Sputtering device using sheet plasma - Google Patents

Abstract

PURPOSE:To form a coating film uniform in thickness on a substrate over a wide range by providing a conductive buffer electrode arranged on the anode side in the vicinity of a target. CONSTITUTION:Columnar plasma is generated at a cathode part 11 and transformed into sheet plasma 10 by a permanent magnet 14 outside a sheet plasma forming chamber 12. A target 18 is opposed to a substrate in a sputtering chamber 16. Meanwhile, a conductive buffer electrode 25 is provided at least on the anode 17 side between the cathode 11 side and anode 17 side near the target 18. The buffer electrode 25 is formed to vertically surround the sheet plasma 10. Consequently, uniform sheet plasma is formed and maintained in the vicinity of the target part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus using sheet-like plasma.

[0002]

2. Description of the Related Art Recently, as a sputtering apparatus of this kind, a cylindrical plasma generated by a cathode acting as a plasma source is formed into a sheet by a permanent magnet provided in a plasma forming chamber, and the sheet-shaped plasma is sputtered. A sheet plasma device of the type that leads to an anode provided in a chamber has been proposed (see, for example, JP-A-63-2).
23171).

More specifically, in this sheet plasma apparatus, a target formed of a substance to be sputtered and a substance sputtered from the target are deposited in a sputtering chamber so as to sandwich the sheet-shaped plasma. And a substrate for doing so are provided so as to face each other. In this device, by applying a bias voltage to the target during the actual sputtering, the target can be sputtered over a wide range, and as a result, the target is formed over a wide range on the substrate. It has the advantage that a film can be formed.

[0004]

In the sheet plasma apparatus having such a structure, even if a uniform sheet-shaped plasma is generated in the vicinity of the target and the anode, a bias voltage is once applied to the target to perform sputtering. Then, a phenomenon that the sheet-shaped plasma has a large plasma density between the target and the anode is observed, and there is a drawback that a film having a uniform thickness cannot be formed in many cases.

An object of the present invention is to provide a sputtering apparatus capable of forming a film having a uniform thickness by investigating the cause of the above-mentioned imbalance of the plasma density of sheet-like plasma and preventing the imbalance of the plasma density. It is to be.

[0006]

According to the present invention, it has been found that the cause of the imbalance of the plasma density of the sheet-like plasma is the disturbance of the electric field between the target and the anode to which a voltage is applied. By setting the electric field between the target and the anode to be substantially the same as the electric field on the cathode side of the target, it is possible to obtain a sputtering apparatus capable of preventing the imbalance of the plasma density of the sheet-shaped plasma.

More specifically, in the present invention, a sheet-shaped plasma is generated from the cathode toward the anode installed in the sputtering chamber, and the sputtering chamber is also provided with a target and a substrate facing each other. In the apparatus, a buffer electrode is provided on at least the anode side of the cathode side and the anode side near the target.

[0008]

In the present invention, since the electric fields on the cathode side and the anode side of the target are kept substantially the same during sputtering, the state of the sheet-like plasma does not change on the cathode side or the anode side of the target. Therefore, the sheet-shaped plasma on the anode side of the target can also prevent nonuniformity of sputtering due to an imbalance of the plasma density.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a sputtering apparatus using a sheet-like plasma according to an embodiment of the present invention comprises a cathode portion 11 which operates as a plasma source.
1 generates a cylindrical plasma. A sheet plasma forming chamber 12 for forming a cylindrical plasma into a sheet is connected to the cathode portion 11 through an opening. Two intermediate electrode portions 13 are provided between the cathode portion 11 and the sheet plasma forming chamber 12, and the plasma from the cathode portion 11 is extracted from the cathode portion by these intermediate electrode portions 13. In this example, permanent magnets (two sets as one set in this example, upper and lower ones) 14 are arranged outside the sheet plasma forming chamber 12, and the magnetic field formed by the permanent magnets 14 causes the cylindrical plasma to become a sheet-shaped plasma. Molded to 10. As a result, the plasma spreads in a direction perpendicular to the surface of the figure, forming a sheet-like plasma 10. In this case, a part of the plasma is generated by the permanent magnet 1 as shown.
4 sucks and spreads toward the inner wall of the sheet plasma forming chamber 12.

The sheet-shaped plasma 10 from the sheet-plasma forming chamber 12 is introduced into a sputtering chamber 16 in which sputtering is performed via an intermediate electrode portion 15 having a slit-shaped opening. In the sputtering chamber 16, an anode part 17 extending in the direction perpendicular to the surface of the drawing is provided so as to receive the sheet-shaped plasma.

Further, the anode part 1 in the sputtering chamber 16
7 at the front, that is, at a position on the cathode 11 side with respect to the anode 17, a target 18 and a table 19 on which a substrate to be formed is mounted are installed so as to face each other with a sheet-shaped plasma interposed therebetween. ing.

Further, outside the sputtering chamber 16,
On the cathode side and the anode side of the sputtering chamber 16, respectively,
A large-diameter coil 20 for generating an external magnetic field is provided, and the sheet-shaped plasma 10 is guided toward the anode part 17 by the magnetic field generated by the large-diameter coil 20.

As shown, the target portion 18
A negative bias voltage is applied to the sputtering chamber 16 by the bias power supply 21. Also,
The sputtering chamber 16, the sheet plasma forming chamber 12, and the two intermediate electrode portions 13 are respectively provided with an external resistance R1.
It is connected to the + side of the main discharge power source 22 via R4. The intermediate electrode portion 15 has the same potential as the anode portion 17.

In FIG. 1, buffer electrodes 25 are provided on the cathode side and the anode side near the target portion 18.
Specifically, the illustrated target portion 18 is the buffer electrode 2
It is surrounded by 5. Further, the buffer electrode 25 of FIG.
It is also provided at a lower position of the sheet-shaped plasma 10 that is symmetrical with the sheet-shaped plasma 8.

A first example of the buffer electrode 25 will be described with reference to FIGS. 2 (a), 2 (b) and 2 (c). In this example, a rectangular body in which two U-shaped pipes 25-1 made of conductive metal are connected by a supporting member 25-2 to form a rectangular shape is connected by a conductive metal rod 25-3, and an insulator is used. The sheet-shaped plasma 10 is positioned above and below by the support legs 25-4 via the. The support leg 25-4 is
It is supported by a bracket 25-5 attached to a column that supports the table 19. The size of the rectangular body is slightly larger than these so that the upper and lower sides can surround the target portion 18 or the table 19. This buffer electrode 25 is also connected to the + side of the main discharge power source 22 via the external resistance R5 (FIG. 1), and the pipe 25-1 of the buffer electrode 25, the support member 25-2, and the conductive metal rod 25-3. Are held at the same potential.

As an example, the distance between the center of the sheet-shaped plasma 10 in the thickness direction and the target portion 18 is 20 mm,
The center of the sheet-shaped plasma 10 in the thickness direction and the table 19
When the distance between the upper substrates is 30 mm, the target portion 18 has a length of 250 mm, and the upper and lower rectangular bodies are arranged at a distance of 40 mm.

FIG. 3 shows a second example of the buffer electrode,
The buffer electrode 30 is formed into a rectangular shape by connecting two pipes 30-1 made of a conductive metal located below the sheet-shaped plasma 10 with a supporting member 30-2 to form a rectangular shape.
The two pipes 30-1 made of a conductive metal located above the sheet-shaped plasma 10 are supported by the support member 30-4 via the conductive metal rod 30-3 erected at 2.
The supporting member 30-2 is supported by the supporting leg 30-5 through the insulator.
To support. The position of the pipe 30-1 is
It may be similar to that shown in FIG.

FIG. 4 shows third and fourth examples of the buffer electrode. In FIG. 4A, the buffer electrode 35 is configured such that the upper and lower pipes and the supporting member shown in FIGS. 2 and 3 can be formed by one conductive metal plate. That is, the slits 35- through which the sheet-shaped plasma 10 can pass are formed on the opposite sides of the rectangular frame-shaped metal plate.
1 is provided. As the support structure for the rectangular metal plate, the same support structure as shown in FIGS. 2 and 3 can be used.

FIG. 4B shows a modification of the buffer electrode 35 of FIG. 4A, which is a pair of upper and lower conductive metal plates 37 having a predetermined interval (similar interval to the slit 35-1 of FIG. 4A). The buffer electrodes 37 of -1 are arranged on the cathode side and the anode side near the target portion 18, respectively, and are configured to be held at the same potential.

Referring again to FIG. 1, when a bias voltage is applied to the target portion 18, the sheet-shaped plasma 10 and the anode 17 near the target portion 18 when there is no buffer electrode.
Since the electric field between them becomes larger than other regions, the anode part 17
As described above, the density of the sheet-shaped plasma 10 in the vicinity increases, and if sputtering is performed in this state, film thickness unevenness occurs and the symmetry of the film thickness distribution is broken.

This is because even if the uniform sheet-shaped plasma 10 is generated before the bias voltage is applied, when the bias voltage is once applied to the target portion 18, it is directly below the target portion 18 due to the influence of this voltage. A new electric potential is superimposed on the sheet-shaped plasma 10 from the sheet-shaped plasma 10 toward the periphery of the anode part 17 side, the cathode side, or the like. In particular, since the electric field acts between the target portion 18 and the anode portion 17 so as to increase, the plasma density in this portion also increases.

On the other hand, when buffer electrodes are arranged upstream and downstream of the target portion 18 to make them equipotential, a new electric field generated by applying a bias voltage to the target portion 18 causes the sheet-shaped plasma 10 to reach the target. Since the upstream and downstream of the part 18 are affected in the same way,
In this part, the imbalance of the plasma density due to the bias of the electric field does not occur unlike the conventional case.

At this time, the potential of the buffer electrode may be the potential of the anode part 17, the potential of the intermediate electrode part 15 or the potential of the sputtering chamber 16. Further, the influence of applying the bias voltage to the target unit 18 is
Since the plasma density of the sheet-shaped plasma 10 between the anode portion 17 and the anode portion 17 is generated, it is not always necessary to provide the buffer electrodes upstream and downstream of the target portion 18, and only between the target portion 18 and the anode portion 17. It may be provided only. Further, the influence of the anode part 17 can be reduced also by setting the buffer electrode to the potential of the sputtering chamber 16 or the potential of the intermediate electrode part 15.

Therefore, it suffices that the buffer electrode is provided on at least the anode side of the cathode side and the anode side near the target portion 18, and it is necessary to form a rectangular shape capable of enclosing the target portion 18 or to use a pipe-shaped electrode. There is no. In other words, the buffer electrodes may be individually arranged on the cathode side and the anode side near the target portion 18, or at least on the anode side near the target portion 18. Also,
It is not necessary to arrange the sheet-shaped plasma 10 above and below. Further, even when the anode is on the plasma source side, it may be arranged only on that side.

[0025]

As described above, according to the present invention, the buffer electrode is arranged near the target portion so as to prevent the disturbance of the electric field near the target portion. A plasma can be formed and maintained. As a result, it is possible to form a film having a uniform thickness over a wide range on the substrate.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a sputtering apparatus according to the present invention seen from a side surface.

2A and 2B are diagrams showing a first example of a buffer electrode which is an essential part of the present invention, FIG. A is a plan view, FIG. B is a side view, and FIG.

3A and 3B are diagrams showing a second example of a buffer electrode which is a main part of the present invention, wherein FIG. 3A is a plan view, FIG. 3B is a side view, and FIG. 3C is a front view.

FIG. 4 is a diagram showing third and fourth examples of a buffer electrode which is a main part of the present invention.

[Explanation of symbols]

 10 sheet-shaped plasma 11 cathode part 12 sheet plasma forming chamber 13, 15 intermediate electrode part 14 permanent magnet 16 sputtering chamber 17 anode part 18 target part 19 table 20 large-diameter coil 21 bias power supply 22 main discharge power supply 25, 30, 35, 37 Buffer electrode

Claims (5)

[Claims] 1. A sputtering apparatus in which a sheet-shaped plasma is generated from a cathode toward an anode installed in a sputtering chamber, and a target and a substrate are arranged to face each other in the sputtering chamber. And a sputtering device using a sheet-shaped plasma, which is provided at least on the anode side and provided with a conductive buffer electrode. 2. The sputtering apparatus according to claim 1, wherein the buffer electrode is configured to sandwich the sheet plasma from above and below. 3. The sputtering apparatus according to claim 2, wherein the buffer electrode is formed by providing slits through which the sheet-shaped plasma can pass, on opposite sides of a conductive rectangular frame-shaped metal plate. A sputtering apparatus using a sheet-shaped plasma characterized by the above. 4. The sputtering apparatus according to claim 1, wherein the buffer electrode is positioned so as to surround the target only on the side of the target above the sheet plasma. The sputtering device used. 5. The sputtering apparatus according to claim 1, wherein the buffer electrode is positioned so as to surround the target only on the substrate side below the sheet plasma. The sputtering device used.