JPS6297329A - Dry etching device - Google Patents

Abstract

PURPOSE:To make it possible to supply sufficient active species to a substrate uniformly by arranging a high molecular material including fluorine or chlorine on either of two opposite cathodes and attaching a substrate to be etched on the surface of another cathode and etching the substrate on the cathode by the active species generated by sputtering of the high molecular material. CONSTITUTION:A high-frequency field is applied to high-frequency cathodes 2 and 3 by a high-frequency source 5 by phase difference of 180 deg.. Consequently, reciprocation of electrons is produced between the high-frequency cathodes 2 and 3 and a high-density plasma is generated. For preventing the contamination due to sputtering of a cathode material, the high-frequency cathodes 2 and 3 are covered with a non-magnetic member 6 composed of Al, Al2O3 or SiO2 etc. A high molecular material 7 including halogen is arranged on the high-frequency cathode 2 and a substrate 8 to be etched is attached to the high-frequency cathode 3. The high molecular material 7 on the high-frequency cathode 2 is sputtered by a high-density plasma and active species are produced by decomposition in the plasma. These active species etch the substrate 8 on the opposed high-frequency cathode 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dry etching apparatus that can be used, for example, in a semiconductor manufacturing process.

[Prior Art J] In recent years, with the increasing integration of VLSIs, dry etching has become mainstream in place of wet etching using a solution in microfabrication processes. Dry etching includes sputter etching, which uses ion bombardment to perform mechanical etching, plasma etching, which uses chemical reactions between radicals and the substrate, and reactive ion etching, which uses acceleration of reactive ions near the cathode. Various types of dry etching devices have been proposed.

Conventionally, plasma of a reactive gas containing halogen has been used, for example, for dry etching of wiring, insulating films, and gate materials of integrated circuits. Since this process uses multiple cans of reactive gas, hydrogen halides are generated in the reaction chamber and piping, causing problems such as corrosion of the reaction chamber and piping and deterioration of the pump oil. Therefore, first, a polymer material containing halogen is placed around the substrate on the cathode, and this polymer material is sputtered with an inert gas, or the polymer material itself is self-sputtered with the gas generated from the polymer material. We proposed a dry etching method that etches the substrate using active species generated by etching.

When etching contact holes using this method, for example, using tetrafluoroethylene resin (Teflon) as the polymer material, there is no generation of hydrogen fluoride, and there is no need to worry about deterioration of pump oil, which was a problem in the past. There is no.

[Problems to be Solved by the Invention] By the way, this method of etching using active species generated by self-sputtering of polymeric materials does not generate hydrogen fluoride and does not allow the equipment to be used stably for a long period of time. However, since the polymeric material is disposed around the substrate to be etched, the supply of active species to the substrate is not uniform and there is a problem in etching uniformity.

In addition, in order to generate enough active species for etching,
The polymer material must occupy a sufficient area on the cathode. When using this method in a batch-type device, there is no problem because the area occupied by the polymer material on the cathode is large, but if this method is used in a single-wafer device, which is required as the diameter of the wafer increases, the cathode becomes larger. Therefore, the advantage of single-wafer processing, which requires a small size of equipment, cannot be fully utilized. Furthermore, the amount of active species generated greatly affects the selectivity of etching. For example, when etching a contact hole using Teflon, the CF-based active species generated from Teflon forms a polymer on S1 and inhibits the etching of Si. Therefore, the Sin/Si selection ratio can be improved by increasing the amount of Teflon sputtered by increasing the amount of Teflon sputtered. For this reason as well, it is necessary to make the area occupied by the polymer material on the cathode sufficiently large.

When performing etching using a polymer material, it is necessary to generate sufficient active species, but if the high frequency power input to the cathode is increased to increase sputtering of the polymer material, the bias applied to the substrate will also increase at the same time. However, there is a problem in that the etching conditions are affected. That is,
Generation of active species from the polymeric material and etching of the substrate cannot be independently controlled.

Therefore, an object of the present invention is to be able to uniformly supply a sufficient amount of active species to a substrate to be etched without requiring an enlarged cathode, and to be able to independently control sputtering and etching of a polymer material. An object of the present invention is to provide a dry etching device.

[Means for Solving the Problems] In order to achieve the above object, the dry etching apparatus according to the present invention is provided with two opposing cathodes to which a high frequency electric field is applied, respectively, in a grounded vacuum processing chamber. A polymeric material containing fluorine or chlorine is placed on the surface of one cathode, a substrate to be etched is attached to the surface of the other cathode, and activation is generated by sputtering the polymeric material placed on the surface of one cathode. It is characterized in that the substrate on the surface of the other cathode is etched with the seeds.

According to another feature of the present invention, a magnetic field generating device is provided for forming a perpendicular magnetic field for generating high-density plasma with respect to two opposing cathodes.

Also, the two opposing cathodes can be placed close to each other, so that a high-density plasma can be generated by the spiral reciprocating movement of electrons between the two cathodes.

[Function] In the dry etching apparatus according to the present invention configured as described above, a polymeric material containing fluorine or chlorine is placed on one of the two opposing cathodes, and a substrate to be etched is placed on the surface of the other cathode. With this installation, active species generated by sputtering of the polymer material placed on the surface of one cathode are uniformly supplied to the substrate on the other cathode, thereby ensuring uniform etching. .

Furthermore, since the polymer material is disposed not around the substrate but on the opposing cathode surface, sufficient active species can be generated without the need to enlarge the cathode.

In this case, by arranging both cathodes close to each other, or by providing a magnetic field generating device that generates a magnetic field perpendicular to the two cathodes disposed facing each other, in the former case, the distance between the cathodes can be increased. High-density plasma with low voltage and high current is generated by the reciprocating movement of electrons, or in the latter case by Penning discharge, which makes it possible to increase the sputtering speed of polymer materials and to achieve high-speed etching with low damage. can be done.

Furthermore, since the high frequency power applied to each cathode can be controlled separately, it is possible to perform sufficient sputtering of the polymer material while reducing the bias applied to the substrate to perform etching without damage.

In addition, the phase difference of the high frequency waves applied to each cathode is 18
If the angle is set to 0°, even higher density plasma can be formed.

[Example] Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 schematically shows an embodiment of a dry etching apparatus according to the present invention, in which numeral 1 denotes a vacuum vessel which is electrically grounded. Two high-frequency cathodes 2.3 are arranged facing each other in the vacuum container 1, and these high-frequency cathodes 2, 3 are connected to a high-frequency power source 5 via a splitting and phase inverting circuit 4 and a blocking capacitor (not shown), respectively. connected to,
A high frequency electric field is applied with a phase difference of 180° from this high frequency 8i15. In this embodiment, the high-frequency cathodes 2 and 3 are preferably placed close to each other, so that electrons can be caused to reciprocate at the high-frequency cathodes 2 and 3 to generate a high-density plasma. High frequency cathode 2, 3
A to prevent contamination by sputtering of the cathode material.
1. It is coated with a non-magnetic material 6 such as Al2O3 or 3i02. The high frequency cathode 2 is made of a polymer material 7 containing halogen.
is arranged, and a substrate 8 to be etched is attached to the high frequency cathode 3.

In the illustrated apparatus configured in this way, the high frequency cathode 2,
The high frequency power supply 5 is divided into 3 and 1 through a phase inversion circuit 4 and a blocking capacitor (not shown).
By applying a high frequency electric field with a phase difference of 80°,
High-density plasma is generated, and the polymer material 7 on the high-frequency cathode 2 is sputtered by this high-density plasma. As a result, it is decomposed in the plasma and active species are generated, and the substrate 8 on the opposing high frequency cathode 3 is etched by the active species.

FIG. 2 shows another embodiment of the present invention, which is provided with a magnetic field generating device that generates a magnetic field perpendicular to the high-frequency cathode, and is electrically grounded as in the embodiment shown in FIG. Two high-frequency cathodes 10.11 are arranged facing each other in the vacuum container 9, and these high-frequency cathodes 10.11 are connected to a high-frequency power source via a splitting and phase inverting circuit 12 and a blocking capacitor (not shown), respectively. connected to 13, 1
A high frequency electric field is applied with a phase difference of 80°. Permanent magnets 14.1 are placed on the back side of each of the high frequency cathodes 10.11.
These permanent magnets 14 and 15 generate a magnetic field perpendicular to each high-frequency cathode, so that electrons reciprocate between the opposing high-frequency cathodes io and 1i while performing a spiral Penning discharge motion. be made into This results in high-density plasma. The thus provided assemblies of high frequency cathode 10 and permanent magnet 14 and high frequency cathode 11 and permanent magnet 15 are respectively coated with a non-magnetic material 16 such as AI, Al2O3 or SiO2 to prevent contamination due to sputtering of the cathode material. has been done. A polymer material 17 containing halogen is disposed on the high frequency cathode 10, and a substrate 18 to be etched is mounted on the high frequency cathode 11.

[Effects of the Invention] As explained above, in the dry etching apparatus according to the present invention, a polymeric material containing fluorine or chlorine is disposed on one of two opposing cathodes, and the surface of the other cathode is etched. The structure is such that the substrate on the other cathode is etched using active species generated by sputtering a polymer material placed on the surface of one cathode. is uniformly supplied to the substrate, allowing etching to proceed uniformly. In addition, since the polymer material is placed on the opposing cathode surface rather than around the substrate, there is no need to increase the size of the cathode.
Sufficient active species can be generated, and therefore, the device is suitable for miniaturization and single-wafer type.

Furthermore, in the device according to the present invention, by arranging both cathodes close to each other or by providing a magnetic field generating device that generates a magnetic field perpendicular to the two cathodes provided facing each other, in the former case, By reciprocating electron movement between the cathodes, or in the latter case by causing Penning discharge, high-density plasma with low voltage and large current is generated, making it possible to increase the sputtering speed of polymer materials and reduce damage. can perform high-speed etching.

Therefore, sufficient productivity can be obtained even when applied as a single-wafer processing apparatus.

Furthermore, since the high-frequency power applied to each cathode can be controlled separately, the apparatus according to the present invention can perform sufficient sputtering of the polymer material while reducing the bias applied to the substrate to perform damage-free etching. be able to.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the invention, and FIG. 2 is a schematic diagram showing another embodiment of the invention. In the figure, 1, 9: Vacuum container, 2.3.10.11: High frequency cathode, 4, 12: Division, phase inversion circuit, 5.13: High frequency power supply, 6.16: Nonmagnetic material 6.7.17 : Polymer material 8
．． 18: Substrate to be etched, i4, 15: Permanent magnet. Figure 1

Claims (1)

[Claims] 1. Two opposing cathodes to which a high-frequency electric field is applied are provided in a grounded vacuum processing chamber, a polymeric material containing fluorine or chlorine is arranged on the surface of one cathode, and the other A substrate to be etched is mounted on the surface of one cathode, and the substrate on the surface of the other cathode is etched with active species generated by sputtering of a polymer material placed on the surface of one cathode. Dry etching equipment. 2. The dry etching apparatus according to claim 1, wherein two opposing cathodes are arranged close to each other, and high-density plasma is generated by reciprocating movement of electrons between the two cathodes. 3. Two opposing cathodes to which a high-frequency electric field is applied are installed in a grounded vacuum processing chamber, and a polymeric material containing fluorine or chlorine is placed on the surface of one cathode, and etched on the surface of the other cathode. The substrate to be processed is attached, and a magnetic field generator is installed to form a magnetic field perpendicular to the two cathodes provided facing each other. By generating high-density plasma due to the spiral movement of electrons, one A dry etching apparatus characterized in that a substrate on the surface of the other cathode is etched with active species generated by sputtering of a polymer material placed on the surface of the cathode.