JPH0559542A - Magnetron sputtering electrode - Google Patents

Abstract

PURPOSE:To uniformalize the erosion of target material and to provide magnetron sputtering electrodes high in the utilizing efficiency of the target material as well as to uniformalize the film forming rate to a substrated confronted with the target. CONSTITUTION:In magnetron sputtering electrodes, target material facing on the area in which electrons are confined is arranged in such a manner that they are divided into mutually electrically insulated plural planar targets 6a, 6b and 6c, and each plural target 6a, 6b and 6c, plural DC power sources 7a, 7b and 7c capable of impressing different electric power independently are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron sputter electrode, and more particularly to a magnetron sputter electrode suitable for improving a film forming rate in forming a thin film on a substrate.

[0002]

2. Description of the Related Art A magnetron sputter electrode forms a region where a magnetic field and an electric field are orthogonal to each other on a target surface in a low-pressure gas atmosphere, traps electrons to generate a high electron density, and is generated by glow discharge. By confining the gas ions in this region, the ion concentration is increased, the deposition rate of the target material on the substrate is improved, and moreover,
It was intended to reduce the inflow of electrons into the substrate. However, the region where the magnetic field and the electric field at which electrons are confined is limited on the surface of the target, and the sputtered material is locally eroded in the region due to the local difference in the magnetic field strength. Usage efficiency is very poor. In particular, the final target utilization efficiency when using a magnetic target is less than about 7% to 9%. In addition, there is an essential problem that the film forming speed on the substrate is also locally different depending on the difference in the erosion conditions of the opposing targets.

In the prior art, in order to suppress the above-mentioned local erosion of the target, for example, Japanese Patent Laid-Open No. 60-
By controlling the position of the magnet used to generate the magnetic field from the back surface of the target as described in Japanese Patent No. 221571, the magnetic field strength distribution on the target surface is changed and the dispersion of the portion where the ion concentration is concentrated. Conversion to
The method of avoiding local erosion is mainly used.
However, in this case, the change in the magnetic field intensity on the target surface due to the change over time in the shape of the target due to erosion is not sufficiently taken into consideration, and the ideal erosion shape has not been reached. The present inventors conducted a study on the position control of the magnet used to generate the magnetic field from the back surface of the target in accordance with the above-mentioned known example, and found that the final target utilization efficiency when the magnetic target was used. Is about 15% to 20
It was about%.

[0004]

In the above-mentioned prior art, no matter how the position of the magnet installed on the back surface of the target is controlled, the erosion of the target is locally caused where the magnetic field strength always exists on the target surface. Increased speed,
Impedance decreases. As a result, the magnetic field vector is further concentrated in this portion, so that the ion concentration is concentrated, local erosion of the target is promoted, and the target material cannot be uniformly eroded. Especially, when the magnetic target is used, the final target utilization efficiency is about 15% to 20%.

This means that, when a thin film is formed using a magnetron sputter electrode, it is necessary to improve the utilization efficiency of the target material required from the viewpoint of cost reduction, productivity improvement, and continuous treatment, even in consideration of the film forming process. Even from the standpoint of reducing the frequency of replacement of the required target material, there is a clear disadvantage.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object thereof is to provide a magnetron sputter electrode which makes the erosion of the target material uniform and has a high utilization efficiency of the target material. To do.
Another object of the present invention is to provide a magnetron sputter electrode capable of achieving uniform film formation rate on a substrate facing a target by suppressing local erosion.

[0007]

In order to achieve the above object, the structure of the magnetron sputter electrode according to the present invention is as follows:
The surface has a target material made of a material to be sputtered, and a magnetic field forming means for generating magnetic field lines that come out of the target material and return to the target material. Sputtering is performed by confining electrons in a region surrounded by the magnetic field lines and the target material. In the magnetron sputter electrode configured to perform the above, the target material facing the region for confining electrons is divided into a plurality of target materials electrically insulated from each other and arranged. More specifically, for each of a plurality of electrically isolated target materials, a plurality of DC power supplies that can independently apply different powers are provided, or for each of a plurality of electrically isolated target materials. It is provided with a DC power supply in which variable resistors are connected in parallel.

In addition, in order to achieve the above-mentioned object, according to the present invention, in the magnetic field for confining the electrons generated on the target surface of the magnetron sputtering electrode,
Electrically insulate the part where the ion concentration is concentrated locally and the target erosion progresses and the part where the ion concentration is sparse and the target erosion is delayed, and power is independently and arbitrarily applied to each part. That is, the electron density is independently controlled to disperse the ion concentration on the target surface. That is, the power applied to the cathode is relatively low for the part where the ion concentration is concentrated and the local target erosion is progressing, and the relatively high power is applied for the part where the erosion is delayed. By applying, it becomes possible to uniformly erode the target and improve the target utilization efficiency.

[0009]

In the cathode of the magnetron sputtering electrode, which has a structure in which a plurality of targets are electrically insulated in order to arbitrarily apply different powers, the target having a relatively high applied power is emitted from the plurality of targets. The generated electrons have a large lifetime due to the large number of electrons emitted per unit and high energy. As a result, the relative electron density existing on the surface of this target with respect to the surface of another target becomes high, and therefore the gas ion concentration can be made high.

By utilizing this phenomenon, the applied power is made relatively low in the part where the target erosion locally progresses in the magnetic field for confining the electrons generated on the target surface. On the other hand, in the portion where the target erosion is slow, the applied power can be increased to make the erosion of the target in the magnetic field that confines the electrons uniform. That is, by providing a target applied power distribution in a magnetic field for confining electrons generated on the target surface of the magnetron sputtering electrode,
The electron density can be controlled independently, the gas ion concentration in the plasma can be controlled, and the target erosion can be made uniform.

[0011]

Embodiments of the present invention will be described below with reference to FIGS. It should be noted that parts corresponding to those of the conventional example in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted. [Embodiment 1] FIG. 1 is a sectional view of a magnetron sputter electrode according to an embodiment of the present invention, FIG. 2 is an erosion sectional shape view of a target when the electrode of FIG. 1 is used, and FIG.
FIG. 6 is a front view of a circular planar magnetron sputter electrode using the sputter electrode structure of FIG. 6, FIG. 6 is a sectional view of a conventional magnetron sputter electrode, and FIG. 7 is an erosion sectional shape view of a target when the electrode of FIG. 6 is used. is there.

FIG. 1 shows a cross section of a circular planar electrode in which the center of the target is O. In the figure, the sputtering target 6 is divided into a plurality of (three in this example) flat plate target materials and arranged.
a, 6b, 6c are divided backing plates 4
a, 4b, 4c, 3 made of the same material
The individual backing plates 4a, 4b, 4c are, for example,
It is electrically insulated by the spacer 3 made of an electrically insulating material such as Teflon or alumina.

The backing plates 4a, 4b, 4
Magnetic field crossing c (see leakage magnetic field line 5 shown in FIG. 1)
The permanent magnets 2 relating to the magnetic field forming means for generating are generated, and the yoke 1 is used to magnetically couple the permanent magnets 2. In addition, the DC power supplies 7a, 7b, 7b of the sputtering targets 6a, 6b, 6c are provided so that individual power can be applied to the electrically isolated sputtering target.
7c is provided.

According to the present embodiment, the applied power is set to be low for the portion where the target erosion is fast and high for the portion where the target erosion is slow.
By independently controlling different applied powers according to the erosion shape, an erosion region as shown by hatching in FIG. 1 is formed, and the sputtering targets 6a, 6b, 6c existing in the magnetic field for confining electrons are high targets. Utilization efficiency becomes possible.

Therefore, the electrode structure according to the embodiment of FIG.
The conventional electrode structure shown in FIG.
Comparison will be made by the erosion cross-sectional shape when used as an e target (target thickness: 4 mm). In the magnetron sputter electrode shown in FIG. 6, an undivided sputter target 6 is held on a backing plate 4, a permanent magnet 2 for generating a magnetic field having a shape straddling the sputter target 6 is arranged, and the magnet 1 is magnetized by the yoke 1. Are combined together.

FIG. 7 shows an erosion sectional shape when a conventional electrode is used. The left and right cross-section cutting direction positions when the center of the target is O are shown on the horizontal axis, and the target erosion shape is shown on the vertical axis. The erosion of the target is concentrated on the part where the horizontal magnetic field strength is maximum, and shows a steep shape. The utilization efficiency of the target was about 7% to 9%. The discharge condition here is that a constant power of 4 kW was applied and the pressure of argon gas in the chamber was 2 mTorr.

FIG. 2 shows an erosion sectional shape when the electrode according to this embodiment is used. It can be seen that although the erosion of the target has a peak in the portion where the horizontal magnetic field strength is maximum, the half-width of the erosion region is 6 times or more as compared with FIG. The utilization efficiency of the target was 50% or more, which was higher than the conventional value. The discharge conditions here are as follows: constant power: 4 kW is applied to the DC power supplies 7a and 7c in FIG. 1, power: 0 kW to 1 kW is applied to the DC power supply 7b, and the argon gas pressure in the chamber is 2 mTorr. Also, an electrically insulated sputtering target 6
A space of 1 mm is provided between each of a, 6b, and 6c.

FIG. 3 shows a front view of the circular planar magnetron sputtering electrode used in the above-mentioned embodiment. In this embodiment, the flat plate targets 6a, 6b and 6c for sputtering are electrically insulated from each other. , The magnet 2 installed on the back surface thereof.

According to the present embodiment, the efficiency of use of the target can be improved as compared with the prior art by providing the distribution of the power applied to the target within the magnetic field that confines the electrons generated on the target surface of the magnetron sputtering electrode. In addition, it is possible to reduce the cost when forming a thin film and reduce the frequency of replacement of the sputtering material. Furthermore, by suppressing local erosion, it is possible to make the deposition rate uniform on the substrate facing the target.

[Embodiment 2] FIG. 4 is a front view of an elliptic planar magnetron sputter electrode according to another embodiment of the present invention. In this example, since the sputtering target has a rectangular shape, based on the structure shown in FIG. 3, the flat target 6A, 6B, 6C for sputtering which is stretched in a track shape and the magnet 2A installed on the back surface thereof are used. It is configured. Also in the case of the example of FIG. 4, the target utilization efficiency was 50% or more.

[Embodiment 3] Next, FIG. 5 is a sectional view of a magnetron sputtering electrode according to still another embodiment of the present invention. In the figure, those having the same reference numerals as those in FIG. 1 are the same parts as those in the embodiment of FIG. The embodiment of FIG. 5 is an example using only one DC power supply 7A. Sputtering targets 6a, 6b, 6 that are electrically insulated
The variable resistors 8a, 8b and 8c are connected in parallel to the DC power supply 7A for each c, and the electric power applied to each target is controlled by changing each resistance value.

In this embodiment, the output of the DC power supply 7A is 12
With respect to kW, the variable resistance 8a is set to 0Ω to set the output to the flat plate targets 6a and 6c for sputtering to 4 kW, and the cathode voltage 4 to each of the targets 6a and 6c for sputtering is set to 0Ω.
Data of 20V and current of 9.5A were obtained. On the other hand, for the sputtering target 6b, a cathode voltage of 400 V and a current of 1.5 A were obtained with the variable resistor 8b set to 2Ω and the variable resistor 8c set to 50Ω in order to output 0.6 kW. Other discharge conditions were the same as in Example 1. In each of the above embodiments, a permanent magnet is used as the magnetic field forming means, but the present invention is not limited to this, and a magnetic field forming means using an electromagnet may be used.

[0023]

As described in detail above, according to the present invention, it is possible to provide a magnetron sputter electrode which makes the erosion of the target material uniform and has a high utilization efficiency of the target material. Further, according to the present invention, it is possible to provide a magnetron sputter electrode capable of achieving uniform film formation rate on a substrate facing a target by suppressing local erosion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a magnetron sputter electrode according to an embodiment of the present invention.

FIG. 2 is an erosion sectional shape diagram of a target when the electrode of FIG. 1 is used.

FIG. 3 is a front view of a circular planar magnetron sputter electrode using the sputter electrode structure of FIG.

FIG. 4 is a front view of an elliptical planar magnetron sputtering electrode according to another embodiment of the present invention.

FIG. 5 is a sectional view of a magnetron sputter electrode according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of a conventional magnetron sputter electrode.

7 is an erosion sectional shape view of a target when the electrode of FIG. 6 is used.

[Explanation of symbols]

2,2A Permanent magnet 3 Spacer 4a, 4b, 4c Backing plate 6a, 6b, 6c, 6A, 6B, 6C Sputtering flat plate target 7a, 7b, 7c, 7A DC power supply 8a, 8b, 8c Variable resistance

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuo Abe, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd.

Claims (3)

[Claims] 1. A target material, the surface of which is made of a substance to be sputtered, and a magnetic field forming means for generating a magnetic field line that exits from the target material and returns to the target material, wherein a region surrounded by the magnetic field line and the target material is provided. In a magnetron sputtering electrode for confining electrons to perform sputtering, the target material facing a region for confining electrons is divided into a plurality of target materials electrically insulated from each other and arranged. Sputter electrode. 2. The magnetron sputter electrode according to claim 1, wherein a plurality of DC power supplies capable of independently applying different powers are provided for each of a plurality of electrically insulated target materials. 3. The magnetron sputter electrode according to claim 1, further comprising a DC power source in which variable resistors are connected in parallel for each of a plurality of electrically insulated target materials.