JPH0964015A - Etching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device by which high speed etching with high evenness and a little charge-up damage is possible on a large bore substrate, by providing a specified vacuum chamber, magnetic field generation means, electric field generation means and board electrode, or by another method. SOLUTION: A magnetic field generation means, forming a ringshaped magnetic neutral line in a cylinder-shaped vacuum chamber 1 whose top surface is dielectric, consists of a permanent magnet 3, which is placed on an upper part dielectric substance 2 with polarities on its top and bottom, and a doughnut and plate-shaped permanent magnet 4 whose diameter is larger than it with the same polarities as those of the permanent magnet 3. And, an electric field generation means consisting of a high frequency coil 5 which applies alternating electric field along the magnetic neutral line formed in the vacuum chamber 1 with the magnetic field generation means, for generating discharge plasma in the magnetic neutral line, is assigned between the permanent magnet 3 and the doughnut and plate-shaped permanent magnet 4. And further, a board electrode 7, which applies D.C. or high frequency bias to a place parallel and distant from the plane made by the to-be-formed magnetic neutral line, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus that uses plasma to etch substances on semiconductors, electronic components, and other substrates.

[0002]

2. Description of the Related Art As a conventional etching apparatus, a magnetron type using a magnet, an ECR discharge type using an electron cyclotron resonance, and a helicon type using a helicon wave have been mainly used. Further, as an etching apparatus that does not use a magnet, a capacitively coupled etching apparatus, an inductively coupled etching apparatus, etc. have been used for a long time. An example of the flat plate inductively coupled etching apparatus is shown in FIG. In the figure, A
Is a process chamber, B is a flat type dielectric partition, C is a substrate electrode,
D is a one-turn induction antenna for plasma generation, E is a high frequency power source for plasma generation, F is a substrate, and G is a high frequency power source for substrate bias. A high frequency power is applied to the plasma generation antenna D from the high frequency power supply E to form plasma inside the chamber to perform bipolar diffusion on the substrate F, and a high frequency power is applied to the substrate electrode C from the high frequency power supply G to cause the plasma on the substrate electrode C. Board F
The substrate F is etched by generating a self-bias.
The process gas H is introduced into the process chamber A through a gas introduction portion I attached near the dielectric partition wall B, and is exhausted from the exhaust port J.

[0003]

It is necessary to form a uniform high-density plasma on the substrate in order to achieve a large-area, high-uniformity and high-speed etching. Moreover, in order to suppress the microloading effect as much as possible, it is necessary to achieve such high density and highly uniform plasma at a low pressure of 0.1 Pa or less.
Further, in the conventional flat-plate inductively coupled etching apparatus as shown in FIG. 4, a quartz plate, which is a dielectric partition located nearby, is sputtered by an electric field generated from the high frequency power applied to the antenna for plasma generation, There are problems that the substrate is contaminated and the etching shape is abnormal. Furthermore, although ECR etching equipment using a magnetic field or helicon wave type etching equipment, which is a conventional technology, can generate high-density plasma at a low pressure of 0.1 Pa or less, it is difficult to perform large-diameter high-uniform etching, and inductive coupling does not use a magnetic field. A large-diameter and high-uniformity plasma can be formed by the discharge method of the electrostatic discharge type or the electrostatic coupling type, but there is a problem that a high-density plasma cannot be formed at a low pressure of 0.1 Pa or less.

In order to solve such a problem of the conventional plasma utilizing apparatus, one of the inventors of the present invention has previously proposed a vacuum chamber as an apparatus for treating an object to be treated using plasma in the vacuum chamber. A magnetic field generating means for forming a magnetic neutral wire in the inside, and an electric field for generating a discharge plasma in the magnetic neutral wire by forming an electric field along the magnetic neutral wire formed in the vacuum chamber by the magnetic field generating means. A discharge plasma processing apparatus provided with a generating means has been proposed (JP-A-7-
(See JP 90632). The present invention makes use of the fact that plasma can be generated even at a pressure of 0.1 Pa or less in the magnetic neutral wire formed at a position apart from the dielectric partition wall by this method, so that high uniformity and charge-up can be achieved on a large-diameter substrate. It is an object of the present invention to provide an etching apparatus capable of high-speed etching with little damage.

[0005]

In order to achieve the above object, an etching apparatus according to the present invention has an annular shape in which a magnetic field is continuously present in a vacuum chamber having a cylindrical upper surface made of a dielectric material. The magnetic field generating means for forming the magnetic neutral line is composed of a permanent magnet having an upper and lower polarity placed on the upper dielectric body, and a doughnut-shaped plate-shaped permanent magnet having an inner diameter larger than that of the permanent magnet and having the same polarity as the permanent magnet. And a plurality of high-frequency coils including a single layer for applying an alternating electric field along the magnetic neutral line formed in the vacuum chamber by the magnetic field generating means to generate discharge plasma in the magnetic neutral line. The electric field generating means is arranged between the permanent magnet and the doughnut-shaped plate-shaped permanent magnet, and a direct current or high frequency bias is applied to a position separated in parallel with the surface formed by the magnetic neutral wire to be formed. It is characterized in that a plate electrode. The upper and lower polar permanent magnets mounted on the upper dielectric can be formed in a disk shape or a donut shape.
By using this etching apparatus, high density and high uniformity plasma can be formed at low pressure. It is the position of the magnetic neutrals formed in the chamber that controls the uniformity. This position is determined by the strength ratio between the permanent magnet disk-shaped magnet and the donut-shaped plate-shaped permanent magnet mounted on the upper dielectric, and the distance between the two magnets.

In order to achieve etching without charge-up damage, according to another feature of the present invention, in addition to the above configuration, in the etching apparatus, the magnetic field extending over the surface of the substrate mounted on the substrate electrode is unlimited. A permanent magnet of opposite polarity to be reduced is located outside the cylindrical side of the vacuum chamber.

[0007]

In the etching apparatus of the present invention thus constructed, the permanent magnet mounted on the upper dielectric partition of the vacuum chamber and the doughnut-shaped plate-shaped permanent magnet having an inner diameter larger than that of the permanent magnet are placed inside the vacuum chamber. A magnetic neutral wire is formed, and when a high frequency wave is introduced from a high frequency applying antenna placed on the magnetic neutral wire and above the dielectric partition wall and discharged, electrons are trapped along the magnetic neutral wire. Efficient discharge is possible. Moreover, in order to further suppress the magnetic field on the substrate, by installing a permanent magnet having a polarity opposite to that of the upper mounting disk-shaped and donut-shaped plate-shaped permanent magnets on the side of the cylindrical vacuum chamber, The magnetic field can be below 5 gauss. As a result, the trap effect on electrons in the plasma can be ignored, and the charge-up phenomenon due to charge separation hardly occurs.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments shown in FIGS. 1, 2 and 3. FIG. 1 shows an embodiment of an etching apparatus according to the present invention. In the apparatus shown in the figure, 1 is a cylindrical vacuum chamber forming a process chamber, the upper surface of which is covered with a flat dielectric partition 2. On the outer surface of the flat plate type dielectric partition 2, a disk-shaped permanent magnet 3 having upper and lower polarities as shown in the figure, and an inner diameter larger than the disk-shaped permanent magnet 3 and a permanent magnet 3 are provided.
A donut-shaped plate-shaped permanent magnet 4 having the same polarity as that of the vacuum chamber 1 is mounted concentrically.
It constitutes a magnetic field generating means for forming a magnetic neutral wire therein. Disk-shaped permanent magnet 3 and donut-shaped plate-shaped permanent magnet 4
A plurality of ring-shaped high-frequency coils 5 each including a single element, which form an electric field generating means, are arranged between and, and the high-frequency coils 5 are connected to a high-frequency power source 6 having a frequency of 13.56 MHz by permanent magnets 3 and 4. An alternating electric field is applied along the magnetic neutral wire formed in the vacuum chamber 1 to generate discharge plasma in the magnetic neutral wire. Further, a substrate electrode 7 is provided at a position separated in parallel with the surface formed by the magnetic neutral wire formed in the vacuum chamber 1, and the substrate electrode 7 is
It is connected to a high frequency power source 8 for applying an RF bias.

In the illustrated apparatus thus constructed, the disk-shaped permanent magnet 3 has a diameter of 80 mm, the donut-shaped plate-shaped permanent magnet 4 has an inner diameter of 300 mm and an outer diameter of 340 mm.
When the surface magnetic field strength is 0.3 terraces, the magnetic neutral line has a radius of 98.
It is formed 5 mm and 57.5 mm below the permanent magnets 3 and 4.
When the thickness of the dielectric partition wall 2 is 30 mm, the magnetic neutral wire is formed 27.5 mm from the inner surface of the dielectric partition wall 2. In this way, since a dense plasma can be formed at a position apart from the vacuum partition surface, the interaction between the plasma and the partition (sputtering, heat inflow by charged particles, etc.) can be suppressed to a small level. The substrate is placed on the substrate electrode 7 200 mm below the surface of the permanent magnet, and the magnetic field on this surface is as low as 5 gauss. FIG. 2 shows a calculation example of a magnetic field formed by a device having such a size.

When the apparatus shown in FIG. 1 is used, a Si substrate with an oxide film is used, and a high frequency power supply of 13.56 MHz is used for RF bias, the pressure of octafluoropropane gas is 0.67.
Pa, RF bias power is 500W, RF antenna power is 15
Despite the fact that the diameter and position of the annular magnetic field neutral wire remain fixed under the condition of 00 W, a high etching rate of 800 nm / min ± 3% and high etching uniformity can be obtained.
Moreover, in the charge-up damage evaluation using an antenna MOS with an antenna ratio of 300,000, no damage was observed over the entire surface of the substrate.

FIG. 3 shows another embodiment of the present invention. In this case, in order to further suppress the magnetic field on the substrate, the upper mounting disk-shaped permanent magnet 3 is provided on the outer peripheral portion of the cylindrical vacuum chamber 1.
Also, a magnetic field correcting cylindrical permanent magnet 9 having a polarity opposite to that of the donut-shaped plate-shaped permanent magnet 3 is provided. The other structure is the same as that of the embodiment of FIG. 1, and the corresponding portions are designated by the same reference numerals. By providing the cylindrical permanent magnet 9, the magnetic field in the vicinity of the substrate is extremely low, the magnetic field on the substrate can be 5 gauss or less, the trap effect for the electrons in the plasma can be ignored, and the charge separation It rarely causes the charge-up phenomenon.

By the way, in the illustrated embodiment, a high frequency of 13.56 MHz is used for the antenna for introducing the high frequency electric field, but the frequency is not limited to this. Similarly, the high frequency applied to the substrate electrode is not limited to 13.56 MHz. When power supplies of the same frequency are used for the antenna and the substrate electrode, a phase control circuit for adjusting the phase between the two power supplies is generally required. Further, in the illustrated embodiment, the diameter of the magnetic neutral wire can be increased by increasing the diameters of the disk-shaped permanent magnet and the donut-shaped plate-shaped permanent magnet. Further, the distance between the formed magnetic neutral wire and the permanent magnet surface can be changed by the distance between the disk-shaped permanent magnet and the donut-shaped plate-shaped permanent magnet. The larger the distance, the larger the distance. Further, although the permanent magnet arranged inside the donut-shaped plate-shaped permanent magnet is disk-shaped in the illustrated embodiment, it can be naturally configured in a donut shape.
Furthermore, although the etching apparatus has been described in the illustrated embodiment, the same effect can be obtained in the CVD apparatus.

[0013]

As described above, according to the present invention, since the magnetic neutral line discharge plasma is used, a uniform plasma can be formed on the substrate, and the etching uniformity which has never been achieved can be achieved. Not only that, etching without charge-up damage is now possible.

[Brief description of drawings]

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

2 is a diagram showing a calculation example of a magnetic field in the apparatus of FIG.

FIG. 3 is a schematic diagram of another embodiment of the etching apparatus according to the present invention using a magnetic field correction magnet.

FIG. 4 is a schematic diagram showing an example of a conventional inductively coupled etching apparatus.

[Explanation of symbols]

 1: Vacuum chamber 2: Flat type dielectric partition wall 3: Disc-shaped permanent magnet 4: Donut-shaped plate-shaped permanent magnet 5: High frequency coil 6: High frequency power supply 7: Substrate electrode 8: High frequency power supply 9: Cylindrical permanent magnet for magnetic field correction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Hayashi 2500 Hagien, Chigasaki City, Kanagawa Prefecture, Japan Vacuum Technology Co., Ltd.

Claims (4)

[Claims] 1. An etching apparatus in which a substrate is etched by using plasma in a vacuum chamber having a cylindrical shape and an upper surface made of a dielectric material, and a position where a magnetic field is continuously present in the vacuum chamber. The magnetic field generating means for forming the annular magnetic neutral line is a permanent magnet having an upper and lower polarity, which is placed on the upper dielectric, and a donut-shaped plate having a larger inner diameter and the same polarity as the permanent magnet. A plurality of high-frequency waves including a permanent magnet for generating discharge plasma in the magnetic neutral line by applying an alternating electric field along the magnetic neutral line formed in the vacuum chamber by the magnetic field generating means. An electric field generating means consisting of a coil is arranged between the permanent magnet and the doughnut-shaped plate-shaped permanent magnet, and a DC or high frequency bias is placed at a position parallel to and separated from the plane formed by the magnetic neutral wire to be formed. An etching apparatus comprising a substrate electrode adapted to apply a voltage. 2. The etching apparatus according to claim 1, wherein the permanent magnets having upper and lower polarities mounted on the upper dielectric body are disk-shaped. 3. The etching apparatus according to claim 1, wherein the permanent magnets having upper and lower polarities mounted on the upper dielectric body are doughnut-shaped. 4. An etching apparatus for etching a substrate by utilizing plasma in a vacuum chamber having a cylindrical shape and an upper surface made of a dielectric material, wherein a position of zero magnetic field existing continuously in the vacuum chamber. The magnetic field generating means for forming the annular magnetic neutral line is a permanent magnet having an upper and lower polarity, which is placed on the upper dielectric, and a donut-shaped plate having a larger inner diameter and the same polarity as the permanent magnet. A plurality of high-frequency waves including a permanent magnet for generating discharge plasma in the magnetic neutral line by applying an alternating electric field along the magnetic neutral line formed in the vacuum chamber by the magnetic field generating means. An electric field generating means consisting of a coil is arranged between the permanent magnet and the doughnut-shaped plate-shaped permanent magnet, and a DC or high frequency bias is placed at a position parallel to and separated from the plane formed by the magnetic neutral wire to be formed. It is necessary to provide a substrate electrode for applying a magnetic field, and to dispose a permanent magnet of opposite polarity on the outside of the cylindrical side of the vacuum chamber in order to minimize the magnetic field exerted on the substrate surface attached to this substrate electrode. Characteristic etching equipment.