JPH079971U - Bias sputtering equipment - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to improve the film thickness distribution of a bias sputtering apparatus in which the distance between the target and the substrate electrode is set to be short. [Structure] In a bias sputtering apparatus in which a target 2 and a substrate electrode 3 are opposed to each other, and high-frequency power supplies 7 and 8 are connected to both the target 2 and the substrate electrode 3, along a circumference of a facing portion 11 of the target 2 and the substrate electrode 3. , An annular auxiliary electrode 12 is installed, and the auxiliary electrode 12 and the ground potential 1
4 are connected by a choke coil 15.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a bias sputtering apparatus that can obtain a uniform film thickness distribution.

[0002]

[Prior art]

 Conventionally, as a device for forming a thin film on a substrate surface by sputtering, a bias sputtering device has been known in which a target and a substrate electrode are opposed to each other and a high frequency power source is connected to both the target and the substrate electrode.

In a process of forming an alumina protective film of a thin film head for writing and reading on a magnetic recording medium, a thick film thickness (several 10 μm) is formed over a large area in a short time. A bias sputtering device is used with the distance between the target and the substrate electrode set as short as 20 to 40 mm.

[0004]

[Problems to be solved by the device]

 As described above, in the bias sputtering device in which the distance between the target and the substrate electrode is set to be short, when plasma is formed by discharge between both electrodes, the distribution of plasma density is not uniform between both electrodes. As a result, there is a problem that the film thickness distribution of the thin film formed by sputtering cannot be uniform.

The uneven distribution of the plasma density is considered to be due to the uneven pressure distribution and flow of the sputtering gas (eg, argon gas) around the electrode. Even if the value was adjusted, it could not contribute much to the uniformity of the plasma density and the thickness distribution.

Attempts have been made to make the plasma density uniform by changing the shape of the ground shield around the electrodes, the shape of the vacuum container accommodating the electrodes, or the discharge process conditions. Could not be effectively acted to improve the.

[0007]

[Means for solving the problem]

 The present invention has been made in view of the above problems, and an object thereof is to improve the film thickness distribution of the bias sputtering apparatus in which the distance between the target and the substrate electrode is set to be short.

The bias sputtering apparatus of the present invention made for such a purpose is a bias sputtering apparatus in which a target and a substrate electrode are opposed to each other and a high frequency power source is connected to both the target and the substrate electrode. A feature is that an annular auxiliary electrode is provided along the outer circumference of the facing portion of the electrode.

The auxiliary electrode can be connected to an impedance adjusting means and a high frequency or direct current power source in addition to a floating potential and a ground potential. Such an auxiliary electrode may have a structure having a water cooling structure.

[0010]

[Action]

 In the bias sputtering device of the present invention, during sputtering, the potential appearing on the auxiliary electrode is applied to the plasma formed between the target and the substrate electrode to change the plasma density distribution, and The distribution of the formed thin film can be improved.

[0011]

【Example】

 The present invention will be described below based on embodiments. FIG. 1 shows a bias sputtering apparatus according to a first embodiment of the present invention, in which a target 2 and a substrate electrode 3 are installed inside a vacuum container 1 so as to face each other. The target 2 is bonded to a base 5 attached to the target electrode 4. The substrate 6 can be mounted on the upper surface of the substrate electrode 3.

Each of the substrate electrode 3 and the target electrode 4 can be cooled by a water-cooling structure (not shown), and high-frequency power sources 7 and 8 are connected to apply high-frequency power between the target 2 and the substrate 6. It is made possible.

The inside of the vacuum container 1 can be evacuated by a vacuum pump 9, and argon gas or other sputtering gas can be introduced through a gas introduction system (not shown). Is designed so that the inside can be adjusted to a predetermined pressure atmosphere. In the figure, 10 is an insulating member, and an auxiliary electrode 12 made of a conductive member formed in an annular shape penetrates the side wall of the vacuum container 1 along the outer circumference of the facing portion 11 of the target 2 and the substrate electrode 3. It is installed via the installed introduction rod 13, and the introduction rod 13 and the ground potential 14 are connected by a cheek coil 15.

FIG. 2 shows a bias sputtering apparatus according to the second embodiment of the present invention. The configuration is substantially similar to that of the first embodiment, and the variable capacitor 16 is connected in parallel to the choke coil 15.

FIG. 3 shows a bias sputtering apparatus according to a third embodiment of the present invention. In this embodiment, the introduction rod 13 of the auxiliary electrode 12 is in an open state, and the auxiliary electrode 12 is in an electrically floating state.

FIG. 4 shows a bias sputtering apparatus according to the fourth embodiment of the present invention. A high frequency power source 18 is connected to the introduction rod 13 of the auxiliary electrode 12 via an impedance matching device 17.

Further, FIG. 5 shows a bias sputtering apparatus according to a fifth embodiment of the present invention. A direct current power supply 19 is connected to the introduction rod 13 of the auxiliary electrode 12.

In the auxiliary electrode 12 of each embodiment, a water cooling pipe is provided along the outer side surface, or the electrode itself has a hollow structure so that cooling water can flow inside the auxiliary electrode. It can also be an electrode.

According to the bias sputtering apparatus of the above embodiment, when discharge is generated between the target 2 and the substrate electrode 3 to form plasma, ions or electrons are generated between the target 2 and the substrate electrode 3. The plasma tries to spread outward due to the repulsive force, but since the auxiliary electrode 12 acts on the plasma that tries to spread outward, the behavior of the plasma that tries to spread outward is promoted. Or, it can be suppressed, and as a result, the plasma density between the electrodes can be made uniform, and the film thickness distribution of the thin film formed on the surface of the substrate 6 can be made uniform over the entire area of the substrate electrode 3. You can

In the first embodiment, the high frequency impedance of the choke coil 15 controls the high frequency component of the power flowing into the auxiliary electrode 12. In the second embodiment, the high frequency impedance of the parallel circuit of the choke coil 15 and the variable capacitor 16 is controlled. Is to control the high frequency component of the electric power flowing into the auxiliary electrode 12, set the potential of the auxiliary electrode 1, and control the behavior of the plasma.

In the third embodiment, the charge of ions or electrons is accumulated in the auxiliary electrode 12 in an electrically floating state, so that the behavior of plasma is controlled by the potential due to the accumulated charges.

Further, the behavior of the plasma is controlled by the high frequency power applied to the auxiliary electrode 12 in the fourth embodiment, and by the direct current power applied to the auxiliary electrode 12 in the fifth embodiment.

When ions flow into the auxiliary electrode 12, there is a possibility of sputtering on the surface of the auxiliary electrode, which contaminates the thin film on the substrate side, so it is necessary to adjust the potential so that sputtering does not occur.

[0024]

[Effect of device]

 As described above, according to the present invention, the behavior of the plasma formed between the target and the substrate electrode to spread outward through the auxiliary electrode is promoted or suppressed, and the uniform plasma density is obtained. Therefore, there is an effect that the film thickness distribution of the thin film formed on the substrate surface can be made uniform over a wide area.

Further, by adjusting the potential of the auxiliary electrode and the impedance with respect to the high frequency current, it is possible to stabilize the plasma and control the film quality of the film thickness formed on the substrate surface.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a fifth embodiment of the present invention.

[Explanation of symbols]

 1 Vacuum Container 2 Target 3 Substrate Electrode 4 Target Electrode 6 Substrate 7, 8, 18 High Frequency Power Supply 11 Opposing Part 12 Auxiliary Electrode 13 Introducing Rod 14 Ground Potential 15 Choke Coil 16 Variable Capacitor 17 Impedance Matcher 19 DC Power Supply

Claims (3)

[Scope of utility model registration request] 1. A bias sputtering apparatus in which a target and a substrate electrode are opposed to each other and a high-frequency power source is connected to both the target and the substrate electrode, and an annular auxiliary electrode is provided along the outer periphery of the facing portion of the target and the substrate electrode. A bias sputtering device characterized by being provided. 2. The bias sputtering apparatus according to claim 1, wherein the auxiliary electrode is connected to an impedance adjusting means and a high frequency or DC power source with respect to the ground potential. 3. The bias sputtering apparatus according to claim 1, wherein the auxiliary electrode has a water cooling structure.