JPS62280379A - Etching device - Google Patents

Abstract

PURPOSE:To surely reduce an auto-bias voltage by surrounding a substrate electrode arranged in a vacuum chamber and loaded with a substrate, a counter electrode opposed to the substrate electrode, and the space between both electrodes by a cylindrical body to confine plasma between both electrodes. CONSTITUTION:The substrate electrode 7 and the counter electrode 8 are provided in a cover 10 communicating with the inside of a vacuum vessel 1, and an insulator is interposed between the bottom face of the electrode 7 and the cover 10. A cylindrical body 11 formed with an insulator such as quartz is furnished in the cover 10, and the electrodes 6 and 17 and the space 15 between both electrodes are surrounded by the cylinder. The inside of the vessel 1 is firstly evacuated, then an etching gas is introduced into the electrode 6 and injected into the space 15 to keep the space 15 in a specified pressure atmosphere. A high-frequency power is impressed on the electrode 7 by a high-frequency power source 12 to generate plasma in the space 15, and the substrate is etched. At this time, the diffusion of plasma into the vessel 1 is prevented by the cylindrical body 11, hence the plasma density is increased, and the auto- bias voltage on the substrate 8 can be reduced.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an etching apparatus that processes a substrate using plasma, and particularly to an etching apparatus that reduces damage caused by ion collisions on the substrate surface t\. The present invention relates to an etching apparatus suitable for etching.

[Conventional technology]

As a conventional technique of this kind for processing a substrate with plasma, there is a technique disclosed in Japanese Patent Application Laid-open No. 74456/1983.

In this conventional technique, a substrate tti as a sputter etching electrode for resetting the substrate and a counter-recirculating electrode facing the substrate are provided in a vacuum chamber, and DC or approximately F power as high frequency power is applied to the substrate electrode. , the counter electrode is placed in an electrically floating state, and the plasma is focused between both tf+ and the plasma density is increased.

In addition, in this conventional technology, a magnet is placed between the substrate electrode and the opposing electrode, and a magnetic field is released to the side open part of the space between the two electrodes, and plasma is generated in the space surrounded by both electrodes and the magnetic field. The aim is to converge the plasma and further increase the plasma density.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology in which a magnet is not placed between both electrodes, the plasma generated between the two electrodes is diffused into the vacuum chamber, and the power supplied to the plasma is transmitted through the vacuum vessel connected to ground and is then released outside. run away. For this reason, it was not possible to generate high-density plasma efficiently, and the effect of reducing the self-bias pressure corresponding to the energy of ions colliding with the substrate was small.

In addition, the above-mentioned prior art '? It is thought that the technique of arranging magnets at bipolar poles can reduce the self-bias bottom pressure.
There is a period of time.

When the self-bias pressure is high, the ions in the plasma are returned to the surface, and the energy that hits the substrate by 4fr becomes large (
Become. As a result, for example, damage to elements on the surface of the semiconductor substrate increases, causing problems such as deterioration of characteristics of elements formed on the substrate and damage to patterns.

SUMMARY OF THE INVENTION An object of the present invention is to provide an etching apparatus that can reliably reduce the self-bias voltage in order to solve the above-mentioned problems.

[Means for solving problems]

The purpose is to provide a substrate electrode disposed in a vacuum chamber on which a substrate is placed, and a counter electrode disposed opposite thereto;
This is achieved by surrounding the space between the two electrodes with a cylindrical body and confining the plasma between the two X-poles.

[Effect]

In the present invention, the space including the substrate tlL pole, the counter electrode, and the space between the two electrodes is surrounded by a cylinder, and the plasma χ is formed between the two electrodes.
I'm trying to lock it up.

Therefore, it is possible to prevent the plasma generated between the two electrodes from leaking from the sides between the two electrodes and the opposing electrode and diffusing into the vacuum chamber. Thereby, the plasma density can be increased and the self-bias voltage on the substrate side? This can be definitely reduced.

Therefore, the energy of ions incident on the substrate is reduced, causing damage to the elements formed on the substrate, resulting in deterioration of characteristics, damage to patterns, and other troubles [Example] Embodiment 7 of the present invention will be described below with reference to the drawings.

Fig. 1 is a vertical cross-sectional view showing an embodiment of the present invention, and Fig. 2 shows the direct pressure on the electrode side of the substrate when the regeneration structure is magnetically brought to the 70-degree center position and when it is grounded. An example of time measurement results? This is a graph showing.

In the etched shank 1 of the embodiment shown in FIG.

A vacuum pipe 2 is connected to the vacuum container 1. This vacuum piping 2 is provided with a vacuum pulp 3 and a vacuum pump 4, so that the inside of the vacuum container 1 can be evacuated. Further, an opening 5 is provided at the bottom of the vacuum container 1 . Further, a cover 10 is housed in the lower part of the vacuum container 1, and the inside of the cover 10 communicates with the inside of the vacuum container 1 through the opening 5.

Inside the cover 10 communicating with the vacuum vessel 1, there are provided a substrate electrode 7 and a counter electrode 6 disposed opposite thereto.

A substrate 8 is placed on the upper surface of the substrate electrode 7 .

An insulating material such as a synthetic resin made of polytetrafluoroethylene is interposed between the bottom surface of the substrate electrode 7 and the cover 10. Furthermore, high frequency power (power) is supplied to the substrate section fiji7 through a high frequency power source 12.

In this embodiment, the opposing center poles 6 are made of metal. Further, the counter electrode 6 is attached to a fixing member 14 and fixed to the bottom of the vacuum vessel 1 via the fixing member 14 and an insulator 13 similar to the insulator 9, and It is arranged in section 5i111I. Furthermore, this counter electrode 6 is brought to a 70-Ting potential state all at once. The pair 1:1 electrode 6 is provided with a plurality of ejection ports (not shown) for ejecting etching gas such as Ar gas toward the substrate electrode 7 side.

A cylindrical body 11 is installed inside the cover 10. In this embodiment, the cylinder 11 is made of an insulating material such as quartz. Further, this cylindrical body 11 is formed in a shape that surrounds a space including the counter electrode 6, the substrate electrode 7, and a space 15 between the two electrodes, and the cylindrical body 11 defines the space 15 between the two electrodes.
It is possible to confine plasma within the space.

A gas pipe 17 is connected to the opposing pole 6.

This gas distribution v17 is provided with a vacuum valve 1 and a gas cylinder 19, and supplies an etching gas such as Ar gas into the counter electrode 6, and from a spout provided in the counter electrode 6 to both electrodes. It is designed to erupt during 15 minutes. Note that an insulator 16 similar to the insulator 9 is provided at the inlet of the gas pipe 17 in the vacuum vessel 1 .

The etching apparatus of the above embodiment is used as follows,
act.

First, inside the vacuum container 1, the vacuum piping 2 and the vacuum valve 3 are
It is evacuated by a vacuum pump 4 via.

After the vacuum container 1 is evacuated, an etching gas such as Ar gas is introduced into the opposing electrode 6 from the gas cylinder 19 through the gas pipe 17 and the vacuum valve 18, and the etching gas is ejected onto the opposing electrode 6 from the outlet. During the interval 15, the etching gas is ejected to maintain a predetermined pressure atmosphere between the two electrodes 15.

The etching gas passes through the gap between the counter electrode 6 and the cylindrical body 11, passes through the vacuum pipe 2 and the vacuum valve 5, and is exhausted by the vacuum pump 4.

When the processing pressure is reached between the two spaces 15, high frequency power 710 is applied to the substrate electrode 7 by the high frequency power source 12, plasma is generated between the two spaces 15, and the substrate 8 is etched.

As described above, the space including the counter electrode 6, the substrate 1, and the gap 15 between both electrodes is surrounded by the cylinder 11, and the plasma generated between the electrodes 15 is prevented from diffusing into the vacuum vessel 1. As a result, the plasma density can be increased and the self-bias voltage on the substrate 8 side can be reduced.As a result, the energy of ions incident on the substrate 8 can be reduced, and therefore the elements formed on the wooden board 8 can be reduced. Damage caused by damage to can be reduced.

FIG. 2 shows the results of measuring the α position on the substrate electrode 7 side as the self-bias voltage of the substrate 8.

In FIG. 2, line A shows the case where the counter electrode 6 is set to the a-ting potential, and line B shows the case when the counter electrode 6 is set to the ground potential. The measurement conditions at this time are both electrodes laj + 5
interval 3Qm), high-rise power (R, F' power) 500W
It is. For example, when the counter electrode 6 is grounded, the voltage is 148 Kv at a pressure of 10 mTorr in the vacuum vessel 1, and when the counter electrode 6 is made floating, the voltage is α16 Kv.
v, which is about 1/10 or more lower.

In addition, please make the gap between the counter electrode 6 and the part 11 large.
Since plasma was also generated within the vacuum vessel 1 through the gap, the effect of reducing the self-bias voltage was small.

Next, FIG. 5 is a separated sectional view showing another embodiment of the present invention.

In the embodiment shown in FIG. 3, a power source 20 is connected to the counter electrode 6. In the embodiment shown in FIG. This configuration also provides an effect similar to that of the embodiment shown in FIG. 1.

The other functions of the embodiment shown in FIG. 3 are the same as those of the embodiment shown in FIG. 1.

Further, according to the present invention, the same effect as the example shown in FIG. 1 can be obtained by the following embodiment.

(1) The counter electrode 6 is set to 70 mm and the cylindrical body 11
may be made of metal, and the cylindrical body 11 may be set at the 70-ring α position.

(II) The counter electrode 6 is made of an insulator, and the cylindrical body 11 is made of metal. :Can be placed in a floating position.

The fill pair 4L, 6 and the cylinder 11 may also be formed of e-binding material.

〔Effect of the invention〕

According to the present invention described above, the space between the substrate electrode placed in the vacuum chamber and on which the substrate is placed, the opposing electrode placed opposite to the substrate electrode, and both electrodes is formed into a cylinder. The structure is such that the plasma is enclosed between the image electrodes, and the plasma generated between the rotating electrodes is prevented from leaking from the sides between the two art and the opposing electrode and diffusing into the vacuum 1. Therefore, the plasma density can be increased,
It has the effect of reliably reducing the self-bias voltage on the substrate side, which in turn reduces the energy of ions incident on the substrate, eliminating problems such as deterioration of characteristics due to damage to elements formed on the substrate and damage to patterns. There is a potential effect.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and Fig. 42 shows the measurement results when the four opposing poles are brought to an electrically floating potential state and when they are grounded, regarding the formation of the polarization side of the substrate. A graph showing an example, FIG. 5, shows another 51! of the present invention! It is a longitudinal cross-sectional view showing an example. 1...Vacuum container, 2...Vacuum distribution/U, 4...Vacuum pump, 6...Opposing! Electrode, 7... Substrate tIL pole,
8... Board, 10... Cover, 11... Cylindrical body, 1
2...High-rise V core source, 15...Between both electrodes of the counter electrode and one pole of the substrate, 17...Gas piping, 19...Gas cylinder I

Claims (1)

[Claims] 1. A substrate electrode on which a substrate is placed and a counter electrode placed opposite to the substrate electrode are provided in a vacuum container, and high frequency power is applied to the substrate electrode to cause the substrate to be heated by plasma. An etching apparatus for processing, characterized in that a space including the substrate electrode, a counter electrode, and a space between the two electrodes is surrounded by a cylindrical body, so that plasma is confined between the two electrodes. 2. The etching apparatus according to claim 1, characterized in that either one of the counter electrode and the cylindrical body is made of metal and is in an electrically floating potential state, and the other is made of an insulating material. . 3. The etching apparatus according to claim 1, wherein the opposing electrode and the cylindrical body are made of an insulator. 4. An etching apparatus according to claim 1, 2, or 3, characterized in that a power source is connected to the opposing electrode.