JPH01100923A - Ion treating apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ion shower processing apparatus suitable for ion processing such as ion etching using an ion source applying microwaves.

[Conventional technology]

Conventionally, as an ion shower treatment device, Japanese Patent Application Laid-Open No. 55-1
As shown in Publication No. 41729, a coil is provided around the periphery of the ionization chamber to generate a magnetic field, and microwaves are introduced into the ionization chamber so that the conditions for electron cyclotron resonance are satisfied, and the energy of the electron microwave is supplied to generate a plasma. A known method is to generate ions of plasma, extract ions from this plasma using an extraction electrode in front of the plasma, generate an ion shower, and process substrates and wafers with ions.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology has a problem in that when the substrate material is an insulator or the film to be processed is an insulator, one surface becomes charged, making it impossible to irradiate the substrate with an ion shower.

An object of the present invention is to enable ion processing without charging even in the case of an insulating material.

[Means for solving problems]

For the above purpose, a rectangular wave alternating current was applied to an extraction electrode for extracting ions, ions and electrons were extracted alternately, and the ratio of ion extraction time to electron extraction time was set on a stage on which a substrate was placed. This is achieved by controlling based on the results of the substrate charging voltage detector.

[For production]

When a rectangular wave alternating current is applied to the extraction electrode, electrons are extracted when a positive voltage is applied, and ions are extracted when a negative voltage is applied.

When the amounts of electrons and ions differ, a charge accumulates on the surface of the insulator. This amount of charge is measured by a charging voltage detector attached to the stage, and when the charging voltage increases positively, the time ratio for extracting electrons is increased, and when it increases to i, the time ratio for extracting ions is increased. to control.

Further, when the charging voltage is positive, the ratio of electron extraction time is increased until the charging voltage becomes zero, and when the charging voltage is negative, the ratio of ion extraction time is increased until the charging voltage becomes zero. In this way, the amount of electrical charge can be controlled to zero, and the amount of ions and electrons extracted can be made equal.

〔Example〕

A sectional view of an embodiment of the present invention is shown in FIG. 1 and will be described below. There is a coil 2 around the ionization chamber 1, which has a power of 875G.
A magnetic field of approximately 100 mL can be generated within the ionization chamber. A waveguide 4 is connected above the ionization chamber 1 via an insulating plate 3, and a frequency of 2.45 GHz is transmitted from the waveguide 4 into the ionization chamber.
microwaves can be supplied, and the ionization chamber 1 is sealed so that it can be evacuated.

A gas supply pipe 5 is opened on the side of the ionization chamber 1.
Gas for ion processing can be supplied from a processing gas supply source (not shown).

There is an extraction electrode 6 at one end of the ionization chamber. A high frequency power amplifier 14 is connected to the extraction electrode 6a, and a signal generator 15 that generates a signal waveform shown in FIG. 2 is connected. The extraction electrode 6b is insulated by an insulating ring 7 and has the same potential as the processing chamber 8.

An exhaust pipe 9 connected to a vacuum evacuation pump (not shown) is provided in the processing chamber 8 so as to be able to exhaust the inside of the processing chamber to a pressure of 10-3 Torr to 10-'' Torr.

There is a stage 10 below the extraction electrode 6.

A measurement electrode 11 is installed under the substrate 13. This measuring electrode 11 is connected to ground via a capacitor 12. The potential difference generated across the capacitor 12 is detected by a detector 16, converted by an A/D converter 17, and sent to a microcomputer 18.

The signal generator 15 mentioned above is designed so that the ratio between the portions 20 and 21 shown in FIG. 2 can be controlled by instructions from this microcomputer.

Next, the operation in this embodiment will be explained.

While supplying processing gas from the supply pipe 5, exhaust is exhausted from the exhaust pipe 9, the inside of the processing chamber is maintained at a vacuum of 10-' to 10-' Torr, and 2.45 GHz is generated from a microwave source (not shown).
When the microwave is supplied, the magnetic field and the microwave create the conditions for electron cyclotron resonance, and plasma is generated in the ionization chamber 1.

A rectangular wave shown in FIG. 2 is applied from the high frequency power amplifier 14 to the extraction electrode 6a. When a positive potential 20 is applied, ions are accelerated between the extraction electrodes 6a and 6b and irradiated into the processing chamber 9. When a negative potential 21 is applied, electrons are irradiated.

The energy of the ions is determined by the positive potential 2o, and the amount of electrons and the amount of ions are determined by the time ratio between the positive potential 20 and the negative potential 21. Therefore, the ion energy can be arbitrarily set by the rectangular wave voltage generated by the signal generator 15.

The amount of ions and electrons are controlled by the accumulation of charge on the substrate 13, which generates a corresponding charge on the measurement electrode 11, which is detected by the potential difference generated in the capacitor 12, and is detected by the microcomputer from the signal generator 15. This is done by changing the time ratio of the signal.

When the amount of ions is greater than the amount of electrons, the amount of negative charge on the substrate 13 increases, so the potential of the capacitor 12 increases in the negative direction. If it is determined that the difference in sampling data taken into the microcomputer increases in a negative direction, the microcomputer changes the output to the signal generator 15 so as to increase the ratio of the ion extraction time to the electron extraction time.

If the measurement result increases in the positive direction, control is performed in the opposite manner to the above. In this way, the amount of electrons and the amount of ions incident on the substrate are controlled to be equal.

However, the charge once charged on the substrate 13 is not eliminated by the above control alone, so if the potential of the capacitor 12 is negative, the time ratio for ions to flow in is increased until the potential of the capacitor 12 reaches the ground potential, and if it is positive, the electrons are It is possible to control the output to the signal generator 15 so that the time ratio of the inflow increases, thereby preventing charging.

The frequency of the rectangular wave applied to the extraction electrode 6a is such that the time it takes for ions to fly between the extraction electrodes 6a and 6b is 10-'
ions and electrons because of the degree of see.

In order to reduce the influence of disturbances in ion energy during switching, a frequency of up to about 10''Hz is appropriate.

In the embodiment described above, the electric charge on the substrate 13 is detected by the capacitor-type measurement electrode 11, but the detection method is not limited to this. As for the structure, it is also possible to measure the amount of irradiated ions and electrons.

Further, as for the plasma generation method, an electron cyclotron resonance method using microwaves and a magnetic field has been described, but it is clear that the present invention is not limited to any method as long as it can generate plasma.

As described above, according to this embodiment, there is an effect that the ion shower treatment can be performed on an insulating material without charging it.

〔Effect of the invention〕

According to the present invention, since an insulating material can be ion-processed using an ion jaw, an insulating substrate can be processed with high precision by ion shirt etching or the like.

[Brief explanation of the drawing]

Fig. 1 is a sectional view and a configuration diagram of an embodiment of the present invention, Fig.
The figure is a waveform diagram of applied voltage. 1...Ionization chamber, 6...Extraction electrode, 11...
・Measurement electrode, 14...High frequency power amplifier, 15...
- Signal generator, 16...Detector, 18...Icrocomputer. 1st Otsu/l...Ichichiya I+Ticket

Claims (1)

[Claims] 1. In an ion processing apparatus having a plasma generation means and an extraction electrode for extracting ions from the plasma, means for alternately extracting ions and electrons, and means for detecting a difference in the amount of extracted ions and electrons and feeding it back to the extraction means. An ion processing device characterized by having.