JPH11241189A - Inductive coupling discharge etching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductive coupling discharge etching device in which the density of plasma to be formed is regulated and is made uniform in the vicinity of a substrate. SOLUTION: The upper part of a cylindrical vacuum chamber 1 is composed of a dielectric substance, the upper part of the dielectric substance is provided with an annular high frequency coil 3 for generating discharge plasma, and moreover, the inside of this annular high frequency coil is provided with an electric field regulating means 5 regulating the static electric field and the induction field. The electric field regulating means is preferably composed of a metallic disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an inductively coupled discharge etching apparatus for etching a substance on a semiconductor, an electronic component, or another substrate by using plasma.

[0002]

2. Description of the Related Art FIG. 4 of the accompanying drawings shows a conventional inductively coupled discharge etching apparatus for generating a discharge plasma on a disk-shaped dielectric A1 provided above a cylindrical vacuum chamber A. A high-frequency antenna B composed of a single coil is provided, high-frequency power is applied to the high-frequency antenna B from a high-frequency power source C for plasma generation, gas is introduced into a cylindrical vacuum chamber A, and plasma is formed at a low pressure. The introduced gas is decomposed, and the generated atoms, molecules, radicals, and ions are positively used, and high-frequency power for bias is applied from the high-frequency power source E to the substrate electrode D in contact with the plasma, and the substrate is placed on the substrate electrode D. The substrate is configured to be etched. A single or multiple high-frequency antenna B is used.

A single antenna etching apparatus shown in FIG. 4 will be described as an example. The etching gas is introduced from the vicinity of the upper flange, and the dielectric gas on the upper portion of the cylindrical vacuum chamber A is formed.
High-frequency power is applied from a high-frequency power source C for plasma generation to a high-frequency antenna B installed on A1 to form plasma. A high frequency power for bias is applied from a high frequency power source E to the lower substrate electrode D. The substrate electrode D, which is in a floating state due to the blocking capacitor, has a negative self-bias potential, and positive ions in the plasma are attracted to etch the substance on the substrate.

At this time, the plasma is generated by the induction electric field in the azimuthal direction radiated from the high-frequency antenna B and the high-frequency antenna B
Excited and formed by its own potential. The former discharge component is called an H discharge, the latter discharge component is called an E discharge,
This E discharge is a discharge due to so-called electrostatic coupling.
As the high-frequency antenna B, conventionally, for example, a pipe diameter of 8 to 10
mm has been used. Even if a flat plate having a diameter approximately equal to the cross-sectional diameter of the pipe is used, the electrostatic coupling component is small and the inductive coupling component is large, so that the characteristics of the plasma are almost the same as when a pipe having a circular cross section is used. With this method,
A plasma with a charged particle density of 10 ¹¹ cm ^-3 is formed.

[0005]

In the inductively coupled discharge etching apparatus, high-frequency power is applied to a high-frequency antenna for forming plasma and an electrode in an electrically floating state for generating a bias voltage. The plasma formed by the high-frequency antenna diffuses toward the substrate electrode, and the ions in the plasma are attracted by the self-bias potential generated at the substrate electrode, and the ions bombard the substrate surface. In general,
With such a diffusion-type inductively coupled discharge, it is very difficult to obtain uniform etching speed for a wafer having a diameter of 300 mm.
Since there is a loss on the wall surface during the diffusion, the density of the peripheral portion decreases, the plasma density becomes convex near the substrate, and the etch rate distribution also becomes convex. Therefore, an object of the present invention is to provide an inductively coupled discharge etching apparatus in which the density of a plasma to be formed is adjusted so as to be uniform near a substrate.

[0006]

According to the present invention, there is provided a plasma generator having a high-frequency coil for generating plasma in a cylindrical vacuum chamber. Is introduced into a vacuum, plasma is formed at a low pressure, and an alternating electric field or a high-frequency electric field is applied to a substrate electrode in contact with the plasma to etch a substrate mounted on the electrode. The upper part of the vacuum chamber is made of dielectric,
An annular high frequency coil for generating discharge plasma is provided above the dielectric, and inside the annular high frequency coil,
An electric field adjusting means for adjusting an electrostatic field and an induced electric field emitted from the annular high-frequency coil is provided.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention,
The electric field adjusting means is constituted by a metal disk. In another embodiment of the present invention, the electric field adjusting means comprises a mesh conductor. In still another embodiment of the present invention, the electric field adjusting means is formed of a conductor film having a thickness of several tens μ or more that does not transmit high frequency.

By providing an electric field adjusting means which can be made of a metal disk or a conductor in the plane of the high frequency antenna and inside thereof, the electrostatic field and the induction electric field radiated from the high frequency antenna are absorbed by the electric field adjusting means. Therefore, the plasma density immediately below the high-frequency antenna is high, but immediately below the metal disk, the electrostatic field and the induced electric field are absorbed by the electric field adjusting means, so that the plasma density is low. As a result, the plasma density distribution near the lower part of the dielectric becomes M-shaped or donut-shaped. Plasma with this form of density distribution is the same as the illuminance distribution of fluorescent lamps,
The diffusion makes the substrate uniform near the substrate, and the etch rate distribution becomes uniform.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows an embodiment of an inductively coupled discharge etching apparatus according to the present invention. In the illustrated apparatus, reference numeral 1 denotes a cylindrical vacuum chamber forming a process chamber having an exhaust port 1a.
Covered with. An annular high-frequency antenna 3 composed of a coil for plasma generation is arranged on the outer surface of the flat dielectric partition 2, and the high-frequency antenna 3 is connected to a high-frequency power supply 4 for plasma generation. By applying high-frequency power, discharge plasma is generated in the vacuum chamber 1. Flat dielectric partition 2 inside annular high-frequency antenna 3
A metal disk 5 is arranged on the outer surface of the metal disk 5.
Has a function of absorbing the electrostatic field and the induced electric field radiated from the high-frequency antenna 3 and reducing the plasma density immediately below the metal disk 5. A substrate electrode 6 is provided in the vacuum chamber 1 via an insulator member 7, and the substrate electrode 6 is connected via a blocking capacitor 8 to a high-frequency power supply 9 for applying an RF bias. Reference numeral 10 denotes a gas inlet.

The operation and operation of the illustrated apparatus having the above configuration will be described. Using the apparatus shown in FIG. 1, the power of the plasma generating high frequency power supply 4 (13.56 MHz) was 2.0 kW, the power of the substrate bias high frequency power supply 9 (2 MHz) was 1 kW, and the pressure was 3 mTorr.
When argon was set to 80 sccm, the etching rate of the silicon oxide film was about 81 nm / min ± 2.83%. The result is shown in FIG. As shown in FIG. 3, the etch rate and its distribution under the same conditions in the conventional apparatus configuration were 84 nm /
min ± 7.1%. By absorbing the electric field induced by the high frequency antenna 3 with the metal disk 5 in this manner,
The plasma distribution in the vicinity of the upper plate-type dielectric partition wall 2 becomes an M type or a donut type, and the plasma distribution becomes uniform in the vicinity of the substrate by diffusion, so that high etch rate uniformity can be obtained.

Although a metal disk is used as the electric field adjusting means in the illustrated embodiment, the electric field adjusting means may be formed of a net conductor or a conductor film having a thickness of several tens μm or more that does not pass high frequencies. Can also. In the illustrated embodiment, A
Although an example of sputter etching by r has been described, a highly uniform distribution can be obtained also in reactive ion etching by introducing a halogen-based gas. Further, even when the present invention is applied to an inductively coupled discharge CVD apparatus, highly uniform film formation can be similarly expected.

[0011]

As described above, according to the present invention, a plasma generator having a high-frequency coil for generating plasma is provided in a cylindrical vacuum chamber, and a gas is introduced into a vacuum. In an inductively coupled discharge etching apparatus, which forms a plasma at a low pressure and applies an alternating electric field or a high-frequency electric field to a substrate electrode in contact with the plasma to etch a substrate mounted on the electrode, the upper part of a cylindrical vacuum chamber is insulated. An annular high-frequency coil for generating discharge plasma is provided above the dielectric, and an electric field for adjusting an electrostatic field and an induced electric field emitted from the annular high-frequency coil is provided inside the annular high-frequency coil. Since the adjusting means is provided, as a large-diameter plasma source corresponding to a large-area substrate, highly uniform plasma can be formed on the substrate electrode. It is possible to obtain an etch rate distribution. Therefore, it is considered that the present invention greatly contributes to the ion etching process used for processing semiconductors and electronic components.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of one embodiment of an etching apparatus according to the present invention.

FIG. 2 is a graph showing an etching rate distribution by the apparatus of FIG.

FIG. 3 is a graph showing an etching rate distribution by a conventional inductively coupled discharge device.

FIG. 4 is a schematic sectional view of a conventional inductively coupled discharge etching apparatus.

[Explanation of symbols]

 1: a cylindrical vacuum chamber 2: a plate-type dielectric partition wall 3: an annular high-frequency antenna 4: a high-frequency power source for plasma generation 5: an annular high-frequency antenna 6: a substrate electrode 7: an insulator member 8: a blocking capacitor 9: a high-frequency power source 10: Gas inlet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiro Morikawa 2500 Hagizono, Chigasaki-shi, Kanagawa Japan Vacuum Engineering Co., Ltd.

Claims (4)

[Claims] 1. A substrate electrode having a plasma generator having a high-frequency coil for generating plasma in a cylindrical vacuum chamber, introducing a gas into a vacuum, forming plasma at a low pressure, and contacting the plasma. In an inductively coupled discharge etching apparatus that applies an alternating electric field or a high-frequency electric field to etch a substrate placed on an electrode, the upper part of a cylindrical vacuum chamber is made of a dielectric, and discharge plasma is applied to the upper part of the dielectric. An inductively coupled discharge characterized in that an annular high-frequency coil for generating electric power is provided, and electric field adjusting means for adjusting an electrostatic field and an induction electric field emitted from the annular high-frequency coil is provided inside the annular high-frequency coil. Etching equipment. 2. The inductively coupled discharge etching apparatus according to claim 1, wherein the electric field adjusting means comprises a metal disk. 3. The inductively coupled discharge etching apparatus according to claim 1, wherein the electric field adjusting means comprises a mesh conductor. 4. The inductively coupled discharge etching apparatus according to claim 1, wherein the electric field adjusting means is made of a conductor film having a thickness of several tens μ or more that does not transmit high frequencies.