JPS634841A - Plasma treatment device - Google Patents

Abstract

PURPOSE:To improve the efficiency of plasma treatment such as sputtering by radiating electromagnetic microwave to at least one electrode, impressing high frequency voltage to electrodes, and forming plasma between a couple of a electrodes. CONSTITUTION:In a sputtering device, a target 13 is mounted to a lower electrode 7 and a wafer 12 is set to an upper electrode 6, and then a treating room 1 is evacuated in high vacuum and supplied with gaseous argon. The microwave emitted by magnetrons 17, 18 is radiated through wave guides 15, 16. By this radiation, a high frequency voltage is impressed between electrodes 6, 7 and a plasma 23 is formed. In this case, the impressed electric power frequency is set at a extremely high value. The self-bias voltage generated between electrodes 6 and 7 is improved thereby, and, by raising the electric charge density, particles to be sputtered are effectively emitted from the target 13 by electrons and efficiently sticked on the wafer 12.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to plasma processing technology, particularly to technology for applying high frequency voltage to form plasma. Till! The present invention relates to a technique that is effective when used in a sputtering apparatus that performs film formation processing such as formation.

[Conventional technology]

2. Description of the Related Art In the manufacturing process of semiconductor devices, some sputtering apparatuses for forming metal films on wafers are configured to apply a high frequency voltage between a pair of electrodes to form plasma.

An example of sputtering technology that describes the sputtering technology is "IC Mounting/Technology" published by Kogyo Research Association Co., Ltd., January 10, 1980, pages 37 to 46.

[Problem that the invention seeks to solve]

In such high m-wave sputtering equipment, the power supply method applied to the electrodes is a contact method, so the applied frequency is kept low, and there is a limit to the self-bias charge density accumulated in the target part, which reduces the sputtering efficiency. The inventor of the present invention has revealed that there is a problem in that there is a limit to the improvement of the performance.

An object of the present invention is to provide a plasma processing technique that can improve processing efficiency.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

An overview of typical inventions disclosed in this application is as follows.

That is, the configuration is such that plasma is formed between a pair of electrodes by irradiating microwave electromagnetic waves to at least one electrode and applying a high frequency voltage to the electrode.

[Effect]

According to the above means, since the high frequency voltage can be applied between the electrodes in a non-contact manner, the applied frequency can be set extremely high.

As a result, the self-bias charge density generated in the electrode is increased, and sputtering efficiency is improved.

〔Example〕

FIG. 1 is a longitudinal sectional view showing a sputtering apparatus which is an embodiment of the present invention.

In this embodiment, this sputtering apparatus has a processing chamber l.
The processing chamber 1 is equipped with a vacuum exhaust device 2 equipped with a vacuum pump such as a cryopump or an oil diffusion pump.
and a gas supply device 3 that supplies an inert gas such as argon gas are connected to each other. Further, a plasma monitor 4 is provided outside the processing chamber 1 so as to be able to see through the window 5 and monitor the plasma.

Inside the processing chamber l, a pair of electrodes 6 and 7 are arranged at the upper and lower parts, respectively, and are supported via insulator supports 8 and 9, and the picture electrodes 6 and 7 are cooled by cooling units 10 and 11, respectively. is configured to be The upper electrode (hereinafter referred to as upper electrode) 6 is configured to be able to hold a wafer 12 as an object to be processed with its main surface facing downward. The lower electrode (hereinafter referred to as the lower electrode) 7 is configured to hold a target 13 made of the same material as the metal film or the like to be deposited on the wafer 12. A magnetoft 14 is provided so that electrons are restrained by a magnetic field.

Waveguides 15, 16 are provided outside the processing chamber 1, arranged one above the other, and an upper electrode 6 and a lower electrode 7 each protrude from one end of the two-groove waveguide 15, 16. Each microwave generator (
(hereinafter referred to as magnetron) 17 and 18 transmit electromagnetic waves in the microwave band (hereinafter referred to as microwave) to each electrode 6.
．． Each of the aperture parts 19.20 is provided in the middle of both groove wave paths 15.16 so as to irradiate the microwaves to the electrodes 6.7 in a concentrated manner. There is.

This sputtering apparatus is equipped with a controller 21 consisting of a computer or the like, and this controller 21 controls the evacuation device 2, the evacuation device 2,
It is configured to control the gas supply device 3, magnetrons 17, 18, etc.

Next, the effect will be explained.

A predetermined target 13 is attached to the lower electrode 7, and the upper electrode 6
After the wafer 12 to be processed is set, the processing chamber 1 is evacuated to a high vacuum by the evacuation device 2, and argon gas or the like is supplied to the processing chamber 1 from the gas supply device 3.

The microwaves emitted by the magnetron 17.18 are condensed by the aperture section 19.20 and are intensively irradiated to the upper and lower electrodes 6.7 through the waveguide 15.16. Due to this microwave irradiation, a high frequency voltage is applied between the upper and lower electric bridges 6.7 under high vacuum, so that plasma 23 is formed. At this time, the applied power frequency is set to be as high as several tens of MHz to several GHz.

The target 13 is X-buttered by the excitation of the plasma 23, and particles to be sputtered are deposited on the wafer 12. As a result, a desired metal film or the like is formed on the wafer 12.

During this process, the formation status of the plasma 23 is monitored by the monitor 4, and based on this status, the controller 21 automatically controls the magnetrons 17, 18, etc. so that the film is properly formed on the wafer 12.

By the way, as the frequency increases, argon atoms with large mass cannot follow changes in the high-frequency electric field, and excessive electrons accumulate on the target surface, resulting in a negative DC self-bias.

This self-bias voltage increases in proportion to the frequency.

Therefore, the present invention focuses on this point, and by applying microwaves to the electrode, the applied frequency can be increased from several tens of MHz to several GHz.
By increasing the self-bias voltage generated in the electrodes 6 and 7, thereby increasing the charge density, particles to be sputtered are effectively ejected by electrons, and the sputtering efficiency is increased.

Furthermore, by automatically controlling the electric field acting on the picture electrode 6.7 during sputtering by monitoring the plasma 23, the sputtering direction (incident angle) of argon atoms acting on the wafer 12 can be controlled. The processing amount (etching amount or devodisilane amount) can be controlled and the processing state can be made uniform, and the following effects can be obtained according to the above-mentioned embodiments.

+11 By irradiating the electrode for plasma formation with microwaves and applying an extremely high radio frequency voltage, the self-bias voltage of the electrode can be increased, which increases the charge density and thereby increases the sputtering efficiency. Can be done.

(2) By increasing the sputtering efficiency, the sputtering speed can be improved, so productivity can be improved.

(3) By monitoring the plasma and automatically controlling the electric field acting on the picture electrode during sputtering, it is possible to control the amount of sputtering processing, thereby improving the accuracy and uniformity of the processing thickness.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the configuration is not limited to irradiating both electrodes with microwaves, but may be configured to irradiate only the negative electrode.

In the above explanation, the invention made by the present inventor was mainly explained in the case where it was applied to the film forming process of sputtering, which is the background application field, but it is not limited to this, and of course it can be applied to the sputtering process , plasma CVD treatment, dry etching treatment, etc. The present invention can be applied at least to all plasma processing apparatuses that perform processing by forming plasma by applying a high-frequency voltage. [Effects of the Invention] Effects obtained by typical inventions disclosed in this application. A brief explanation is as follows.

By irradiating the electrode for plasma formation with microwaves and applying an extremely high radio frequency voltage, it is possible to increase the self-bias voltage of the electrode and increase the charge density, thereby increasing plasma processing efficiency.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a sputtering apparatus which is an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Processing chamber, 2... Vacuum exhaust device, 3... Gas supply device, 4... Plasma monitor, 5... Window part, 6.7,
... Electrode, 8.9 ... Insulator support, 10.11.
...Cooling section, 12...Wafer (workpiece), 13...
・Target, 14...Magnet, I5.1G...
・Waveguide, 17.18...Magnetron, 19.20
... Aperture section, 21... Controller, 22... Processing condition information, 23... Plasma. , -Representative Patent Attorney Katsuma Ogawa゛1,

Claims (1)

[Claims] 1. The device is characterized in that it is configured to form plasma between a pair of electrodes by irradiating microwave electromagnetic waves to at least one electrode and applying a high frequency voltage to the electrodes. Plasma processing equipment. 2. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is configured such that the microwave electromagnetic waves are irradiated to both of the pair of electrodes.