JP2006310416A - Dry etcher - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry etcher which uniformly etches a plurality of substrates. <P>SOLUTION: The dry etcher comprises an evacuatable chamber 5, a chemical species generating source 2 mounted in the chamber 5 for generating a chemical species 3 having etching actions, and a substrate holder 1 disposed in the chamber 5 for holding a plurality of substrates 4 under process to expose them to the chemical species 3, thereby etching the surface of each substrate. The holder 1 has a shape capable of holding the plurality of substrates 4 so as to conform with the density distribution of the chemical species 3 having the etching action, thereby making the etching process of each substrate 4 uniform. The holder 1 has, e.g., a dome-like shape forming a part of a symmetric body of revolution of a circle, ellipse, or a hyperbola or parabola. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dry etching apparatus. More specifically, the present invention relates to a substrate holding structure for holding a plurality of substrates to be processed by dry etching and arranging them in a chamber.

  Dry etching apparatuses are roughly classified into a reactive ion etching method and a plasma etching method. In reactive ion etching, high-frequency power is applied to the electrode on which the substrate to be processed is placed, and the generated negative self-bias voltage accelerates the ions generated from the plasma to bombard the substrate, etching the surface. Process. In contrast, plasma etching etches the substrate surface using radicals generated from plasma without applying a bias to the substrate to be processed. In recent years, a method using reactive ion beam etching, which can be processed at a high aspect ratio microfabrication and a high etching rate, has been proposed. Conventional dry etching apparatuses are mainly developed as semiconductor manufacturing apparatuses, and there are many examples using a silicon wafer as a substrate. The most important point in the dry etching process of a silicon wafer is the realization of a uniform etching rate. For this purpose, a dry etching apparatus is known in which the generation source of chemical species such as an ion source is improved and the etching distribution is made uniform. Also known is a method for improving the uniformity of etching by improving the substrate holding mechanism. For example, a method having a substrate rotating mechanism has been put into practical use as a standard technique.

As a conventional dry etching apparatus, an apparatus capable of simultaneously processing a plurality of substrates has been put into practical use. Also in this case, it is the most important matter to make the etching processing of a plurality of substrates uniform. For example, Patent Document 1 and Patent Document 2 below describe a technique for making the etching processing of a plurality of substrates uniform.
JP 05-243189 A Japanese Laid-Open Patent Publication No. 01-1119025

  FIG. 4 is a schematic cross-sectional view showing the dry etching apparatus disclosed in Patent Document 1. As shown in FIG. As shown in the figure, the cathode electrode 13 has a spherical body structure, and a substrate 4 to be processed is loaded on the inside thereof. The anode electrode 12 also has a spherical structure, and is disposed at the center of the cathode electrode 13. A power source 14 is connected to the cathode electrode 13, while the anode electrode 12 is grounded. According to this structure, since the cathode electrode 13 and the anode electrode 12 have the same structure, the electric field distribution between the anode and the cathode is almost uniform at any position, so that the processing variation of the substrate 4 is reduced. According to the dry etching apparatus disclosed in Patent Document 1, since the cathode electrode 13 and the anode electrode 12 have a substantially spherical structure, the electric field distribution is uniform at any position on the cathode electrode, and the substrate loading position and the substrate loading position are obtained. It is possible to perform uniform processing without depending on.

  FIG. 5 is a schematic diagram showing an ion beam etching apparatus described in Patent Document 2. As shown in FIG. This apparatus includes an ion source 2a, an ion beam 3a extracted from the ion source 2a, and a sample stage 1a for fixing the substrate 4 to be etched by the ion beam 3a. Here, the ion beam 3a emitted from the ion source 2a is diverging, and a plurality of substrates 4 are arranged and fixed on the sample stage 1a. The sample stage 1a has an upper surface 1s formed in a concave curved shape, and is inclined upward as it goes to the outer periphery from the center. The inclination of the concave concave shape of the sample stage 1a is formed so that all the angles formed by the respective substrates 4 arranged on the upper surface portion 1s and the ion beam 3a incident thereon are substantially equal. According to this structure, the substrate 4 is arranged so that the incident angles of the ion beams 3a irradiated to each of the plurality of substrates 4 are substantially equal to the ion beam 3a emitted from the ion source 2a to the substrate 4 side. Then, etching is performed. Therefore, the ion beam etching speed and shape difference can be reduced without depending on the structure of the ion source 2a, and high aspect ratio etching can be performed.

  The dry etching apparatus described in Patent Document 1 uses two substantially spherical electrodes in parallel to achieve uniform electric field distribution. However, depending on the distribution of chemical species that perform the etching action in the chamber, uniform etching may not always be realized. In the dry etching apparatus described in Patent Document 2, the incident angle of the ion beam with respect to the substrate is made uniform. Even in this system, there is a problem that the etching process is not uniformly performed depending on the distribution of chemical species that perform the etching action in the chamber.

  In view of the above-described problems of the conventional technology, an object of the present invention is to provide a dry etching apparatus capable of performing a uniform etching process on a plurality of substrates. In order to achieve this purpose, the following measures were taken. That is, the present invention comprises a chamber that can be evacuated, a chemical species generation source that generates a chemical species that is mounted in the chamber and has an etching action, and a plurality of substrates that are disposed in the chamber and are to be processed. In a dry etching apparatus having a substrate holding member for exposing to a chemical species and performing an etching process on the surface of each substrate, the substrate holding member has a plurality of chemical species so as to follow a density distribution of the chemical species that perform an etching action. The substrate has a shape that can hold the substrate, and the etching process of each substrate is made uniform.

  Preferably, the substrate holding member has a dome shape that forms a part of a rotationally symmetric body of a circle, an ellipse, a hyperbola, or a parabola. Alternatively, the substrate holding member has a tunnel shape that forms a part of a circular, elliptical, hyperbolic, or parabolic translational symmetric body.

  According to the present invention, the substrate holding mechanism of the dry etching apparatus is shaped according to the density distribution of the chemical species that perform the etching action. Accordingly, a uniform etching process can be performed on a plurality of substrates regardless of the shape of the distribution of chemical species generated from the generation source in the chamber. For this reason, the etching process which reduced the bad influence given to each board | substrate is possible. In addition, a uniform etching process can be obtained with a simple chemical species generation source structure.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic block diagram showing the structure of a dry etching apparatus according to the present invention. As shown in the figure, this dry etching apparatus includes a substrate holding member 1, a chemical species generation source 2, and a chamber 5 as a basic configuration. The chamber 5 is connected to a vacuum pump 7 and can be evacuated. The chemical species generation source 2 is mounted in the chamber 5 and generates a chemical species 3 having an etching action. The generated chemical species 3 exhibits a predetermined density distribution in the evacuated chamber 5. The substrate holding member 1 is disposed in the chamber 5 so as to face the chemical species generation source 2, holds a plurality of substrates 4 to be processed and exposes them to the chemical species 3. The surface is etched.

  As a feature of the present invention, the substrate holding member 1 has a shape capable of holding a plurality of substrates 4 so as to follow the density distribution of the chemical species 3 that performs the etching action, and the etching process of each substrate 4 is made uniform. Yes. In one embodiment, the substrate holding member 1 has a dome shape that forms a part of a rotationally symmetric body of a circle, an ellipse, a hyperbola, or a parabola. In another aspect, the substrate holding member 1 has a tunnel shape whose shape is a part of a circular, elliptical, hyperbolic or parabolic translational symmetric body.

  With continued reference to FIG. 1, the embodiment of the present invention will be described in detail. In this embodiment, a chemical species generating source 2 that is an ionization unit and a substrate 4 made of a silicon wafer coated with a carbon film that is an object to be etched are placed in a chamber 5. A plurality of substrates 4 are held by the substrate holding member 1. The chamber 5 is evacuated to about 2 Pa by a vacuum pump 7, and a gas introduction system 6 capable of introducing argon and oxygen is connected to the chamber 5.

  Next, the etching process will be described in detail. The substrate holding member 1 has a spherical crown-shaped dome shape and has an outer shape of 300 mm, a height of about 50 mm, and a curvature radius of about 250 mm. The dome-shaped substrate holding member 1 holds a substrate 4 made of a 20 × 20 mm silicon wafer coated with a carbon film at positions of 30 mm, 60 mm, 90 mm, and 120 mm from the center. The degree of vacuum at the start was set at 2.0 Pa, argon was introduced from the gas introduction system 6 at about 10 sccm, and a pulse bias was applied to each substrate 4 to perform etching for about 25 minutes. As a result, the substrate 4 held at a position of 120 mm was somewhat over-etched, but the substrates 4 held at 30 mm, 60 mm, and 90 mm were almost uniformly etched. This is presumably because the density distribution of the chemical species 3 that performs the etching action has a substantially spherical crown shape, so that uniform etching is achieved as a whole. However, since it was not completely similar to the spherical crown shape, a deviation from the holding position occurred, and it is considered that a slight over-etching occurred in the substrate 4 arranged at a position of 120 mm.

  As a comparative example, an etching process was performed using a disk plane type substrate holding member having a diameter of 300 mm. In this comparative example, a substrate 4 made of a 20 × 20 mm silicon wafer coated with a carbon film at positions 30 mm, 60 mm, 90 mm, and 120 mm from the center of the disk-type substrate holding member 1 was mounted. At the start of processing, the degree of vacuum was 2.0 Pa, and about 10 sccm of argon was introduced from the gas introduction system 6, and a pulse bias was applied to the substrate for etching for about 25 minutes. As a result, the substrate 4 placed 30 mm and 60 mm from the center was etched finely. However, a little carbon film coat was left on the substrate 4 arranged at 90 mm, and the etching did not progress much on the substrate 4 arranged at 120 mm. When etching was performed with a treatment time of 40 min, the substrate 4 held at 30 mm was overetched, and conversely at 120 mm, it was overetched, and the remaining coating was observed. Therefore, the etching process of each substrate cannot be performed uniformly in the comparative example using the disk-shaped planar substrate holding member as compared with the embodiment using the spherical crown-shaped dome type substrate holding member.

  In the above-described embodiment, as the chemical species generation source 2, an ionization unit including a fragment for generating thermal ions and an anode for extracting ions is used. As the introduced gas, one of argon and oxygen or a mixed gas thereof is used. In addition, a plasma gun, an ion beam, or the like can be used to generate chemical species including gas ions or radicals introduced into the chamber 5. As the introduced gas, use of an inert gas such as another rare gas, or a reactive gas such as oxygen or a fluorine-based gas may be considered.

  Regardless of the type of the substrate 4, a silicon wafer, a glass plate, a mold, a synthetic resin component, or the like can be used. It can also be used for etching various functional thin films such as various protective films, optical thin films, and conductive films.

  Further, the etching rate can be further increased by applying a constant bias charge to the substrate holding member 1. In the embodiment described above, a pulse bias having a bias voltage of about 1 kV and a frequency of 2 kHz is applied to the substrate holding member 1. In addition, an RF bias, a pulse bias, a DC bias, or the like may be applied. It is possible to install one or more working electrodes as required.

  The shape of the substrate holding member 1 is made substantially in line with a certain density distribution of the chemical species 3. For example, when the chemical species generation source 2 is a dot and the density distribution is a sphere, the substrate holding member 2 has a dome shape that forms a part of a spherical surface. As shown in FIG. 2, when the cross section in the longitude direction of the density distribution forms an ellipse, a hyperbola, a parabola, or the like, the dome-shaped substrate holding member 1 whose rotational symmetry body forms a part is used. In this case, since the substrate holding member 1 is a rotationally symmetric body, it is possible to provide a rotating mechanism, and more uniform etching can be expected.

  When the chemical species generation source 2 is linear and the density distribution is a semi-cylindrical shape, the substrate holding member 1 has a semi-cylindrical tunnel shape. Further, as shown in FIG. 3, when the cross-section of the density distribution of chemical species forms an ellipse, a hyperbola, a parabola, or the like, the substrate holding member 1 similarly has a tunnel shape that forms a part of a translational symmetric body.

  When the density distribution of the chemical species 3 generated in the chamber by the chemical species generation source 2 is along the free-form surface shape, the substrate holding member 1 may be a free-form surface shape along the density distribution. Further, the density distribution of the chemical species 3 and the shape of the substrate holding member 1 are not necessarily completely similar. For example, when the cross section of the distribution of the chemical species 3 is an ellipse, the substrate holding member 1 is formed in a shape that is close to a shape that forms part of a sphere, so that the etching rate is higher than the planar shape shown in the comparative example. The distribution can be made uniform.

It is a block diagram which shows the dry etching apparatus concerning this invention. It is a typical perspective view which shows the shape of the board | substrate holding member used for the dry etching apparatus concerning this invention. It is a typical perspective view which similarly shows the shape of a board | substrate holding member. It is typical sectional drawing which shows an example of the conventional dry etching apparatus. It is a schematic diagram which shows the other example of the conventional dry etching apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate holding member, 2 ... Chemical species generation source, 3 ... Chemical species, 4 ... Substrate, 5 ... Chamber, 6 ... Gas introduction system, 7 ... Vacuum pump

Claims (3)

A chamber that can be evacuated, a chemical species generation source that generates chemical species having an etching action mounted in the chamber, and a plurality of substrates to be processed that are disposed in the chamber are held and exposed to the chemical species. In a dry etching apparatus having a substrate holding member for performing an etching process on each substrate surface,
The dry etching apparatus characterized in that the substrate holding member has a shape capable of holding a plurality of substrates so as to follow the density distribution of the chemical species that perform an etching action, and uniformizes the etching process of each substrate.   2. The dry etching apparatus according to claim 1, wherein the substrate holding member has a dome shape that forms a part of a rotationally symmetric body of a circle, an ellipse, a hyperbola, or a parabola.   2. The dry etching apparatus according to claim 1, wherein the substrate holding member has a tunnel shape that forms a part of a circular, elliptical, hyperbolic, or parabolic translational symmetric body.

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