JPH0551775A - Plasma etching device - Google Patents

Abstract

PURPOSE:To provide a plasma etching device possible to increase etching speed without using a permanent magnet or an electro-magnet. CONSTITUTION:The solenoid coil 1 possible to generate magnetic field is one of an electrode and a material to be etched, which is another electrode, is arranged in the inside of the solenoid coil 1, and plasma density increases by electron cyclotron movement between the solenoid coil 1 and the material to be etched 7.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a plasma etching apparatus.

[0002]

2. Description of the Related Art A conventional etching apparatus is shown in FIG. This etching device uses active species and ions generated by plasma excitation, and is called a plasma etching device. That is, as shown in FIG. 2, in a vacuum atmosphere container 8, a pair of electrodes 1 and 7 are arranged so as to face each other. ing. A work 12 is placed on the electrode 7. The vacuum chamber 8 is connected to a vacuum exhaust pump 10 and is in a vacuum state, and an etching gas is introduced through a pipe 9. Therefore, due to the potential between the electrodes 1 and 7, discharge plasma is generated and maintained between them,
The etching gas is divided into positive ions and negative ions (plasma state), and as shown in FIG. 3, the positive ions collide with the negative potential side electrode and physically etch the work surface. Here, in order to increase the etching rate, it is considered that electron cyclotron motion using a magnetic field is used to increase the frequency of collision between electrons and neutral particles and increase the plasma density. The electron cyclotron motion is a swirling motion of electrons due to a magnetic field. In the plasma etching apparatus, a combination of a plurality of annular permanent magnets 13 or rectangular parallelepiped permanent magnets 13 shown in FIGS. 4A and 4B is considered as a magnet for performing electron cyclotron motion. In the figure, 7 is an electrode, and 14 is a pole piece for connecting magnets to each other.

[0003]

Thus, the magnetron type plasma etching apparatus using the magnet 13 is as follows.
Since a magnetic field is used to increase the etching rate, it is necessary to install a permanent magnet or an electromagnet in the vicinity of the electrodes, which has the disadvantage of increasing the complexity and size of the device. The present invention has been made in view of the above-mentioned prior art, can obtain the same effect without the need for permanent magnets or electromagnets, and, when using a high frequency power supply, etching while heating the work. An object of the present invention is to provide a plasma etching apparatus capable of performing the above.

[0004]

Means for Solving the Problems The structure of the present invention which achieves such an object is to introduce an etching gas into a vacuum chamber in which a pair of electrodes are arranged, and to introduce a gas in a plasma state between the electrodes. In a plasma etching apparatus that performs plasma etching by causing positive ions to collide with a relatively negative potential among the electrodes, a solenoid coil that can generate a magnetic field is used as an electrode having a relatively positive potential among the electrodes. It is characterized in that an etching object is arranged inside the solenoid coil as an electrode which is used and has a relatively negative potential among the electrodes.

[0005]

[Operation] Since one electrode is a solenoid type coil,
A strong magnetic field can be generated in the space surrounded by the coil, and since the solenoid type coil has a relatively positive potential, the conventional permanent magnet or electromagnet is not required. Between the solenoid type coil and the etching target surrounded by it,
Since there is a potential difference, it has a plasma etching action.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of the present invention. This embodiment shows an example in which the work 7 is induction-heated while being etched. That is, in the vacuum chamber 8, the solenoid coil 1 and the work 7 which are a pair of electrodes are arranged. The vacuum chamber 8 is brought into a vacuum state by a vacuum exhaust pump 10 and an etching gas is introduced through a pipe 9. Work 7 is solenoid coil 1
Surrounded by and grounded. The solenoid coil 1 is
It is composed of a conductor through which a current can flow, and is connected to the DC power supply 2 and is also connected to the high frequency power supply 5 via the matching unit 4 composed of the capacitor and the transformer 6. Therefore, for example, 1000 is applied to the solenoid coil 1 by the DC power supply 2.
By applying a positive voltage of up to 2000 V, a discharge can be generated between the work 7 and the solenoid type coil 1, a plasma state can be generated, and a magnetic field 15 is generated as shown in FIG. Can be made Further, the work 7 can be dielectrically heated by passing a high-frequency current from the high-frequency power supply 5 to the solenoid coil 1. Since the solenoid coil 1 is always kept at a positive potential with respect to the work 7, the transformer 6 of the matching device 4 serves both for matching and for insulating. In the plasma etching apparatus of the present embodiment having the above-mentioned configuration, the solenoid coil 1 is constantly applied with a positive voltage of 1000 to 2000 V by the DC power source 2, so that the inside of the work 7 is in a plasma state and 500 to 1000. A magnetic field 15 of about Gauss is generated. For this reason, the electron has a frequency of 10 ⁹ H due to electron cyclotron motion.
A swirling motion of about z occurs and the plasma density increases.
Further, the positive ions in the plasma collide with the solenoid type coil 1 toward the work 7 having a negative potential of -1000 to -2000 V, which causes an etching action.
Since the solenoid type coil 1 always maintains a positive potential, the solenoid type coil 1 does not have an etching action. Further, since a high-frequency current flows from the high-frequency power source 5 to the solenoid coil 1, the work 7 positioned inside the high-frequency current is induction-heated. In particular, when a thin plate conveyed on a line is used as the work 7, the heating in the next step can be used also. Next, another embodiment of the present invention will be described. In this example,
In this example, a flat coil is used as the solenoid coil 1. By doing so, the surface area of the solenoid coil 1 is increased, so that the plasma density can be further improved. The other configurations are the same as those of the above-described embodiment, and the same effects are produced. In the above embodiment, the DC power source and the high frequency power source were used together as the power source, but when induction heating of the work is not necessary, it is possible to use only the DC power source, and in that case, the high frequency power source and the transformer. Also, there is an advantage that a matching device is unnecessary.

[0007]

As described above in detail with reference to the embodiments, in the present invention, the solenoid type coil is used as one electrode and the other electrode is used as a workpiece for etching. Therefore, a permanent magnet and an electromagnet are not used. However, by generating a magnetic field and electron cyclotron motion, the plasma density can be increased and the etching rate can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a plasma etching apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional plasma etching apparatus.

FIG. 3 is an explanatory diagram showing a state of physical etching.

4A and 4B are perspective views of electrodes and magnets used in a magnetron type plasma etching apparatus.

FIG. 5 is a configuration diagram of a plasma etching apparatus according to another embodiment of the present invention.

6 (a) and 6 (b) are respectively a perspective view and a plan view showing how a magnetic field is generated in an embodiment of the present invention.

[Explanation of symbols]

 1 Solenoid type coil 2 Current 3 DC power supply 4 Matching device 5 High frequency power supply 6 Transformer 7 Work 8 Vacuum tank 9 Piping 10 Vacuum exhaust pump 12 Work 13 Permanent magnet 14 Pole piece 15 Magnetic field

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Tsurusaki 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Research Laboratory (72) Inventor Toshio Taguchi 4 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture 6-22 No. 6 Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Ritsuo Hashimoto, 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Hiroshima Prefecture (72) Inventor Heisaburo Furukawa Hiroshima City, Hiroshima Prefecture 6-31 Minamikannon, Nishi-ku, Ryosen Engineers Co., Ltd.

Claims (1)

[Claims] 1. An etching gas is introduced into a vacuum chamber in which a pair of electrodes are arranged, and positive ions of the gas in a plasma state between the electrodes are made to have relatively negative potential among the electrodes. In a plasma etching apparatus that performs plasma etching by colliding, a solenoid coil that can generate a magnetic field is used as an electrode having a relatively positive potential among the electrodes, and a relatively negative potential is used among the electrodes. A plasma etching apparatus, wherein an object to be etched is arranged inside the solenoid coil as an electrode.