JPS6231125A - Dry etching device - Google Patents

Abstract

PURPOSE:To uniformly supply a gas into a substrate by a method wherein a gas is supplied to a container with plural gas supply holes arranged symmetrically to the surface of a substrate to be processed so that an etching gas and a deposition gas are uniformly supplied to the surface of the substrate. CONSTITUTION:An etching gas containing harogen elements, etc. is supplied through a electric discharge pipe 24, and the etching species as its active species are introduced into the container 10 from the gas supply hole 21 of the first gas introduction pipe 20 and uniformly supplied to the surface of a substrate to be processed 11. On the other hand, a deposition gas is introduced into the container 10 from the gas supply hole 31 of the second gas introduction pipe 30 through a piping 32 and supplied to the surface of the substrate to be processed 11. The deposition gas is activated by the etching species to be a deposition species. Moreover, the light from a light source 13 is vertically and uniformly irradiated onto the substrate to be processed 11 without being shielded by the gas introduction pipes 20 and 30.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a dry etching 5A apparatus used in a semiconductor device manufacturing process, and more particularly to a dry etching apparatus that performs anisotropic etching using light.

[Technical background of the invention and its problems]

Conventionally, dry etching techniques using charged particles, typified by reactive ion etching, have been mainly used as microfabrication methods in semiconductor device manufacturing processes.

However, in current semiconductor devices, it is known that the incidence of these charged particles on a substrate to be processed has an adverse effect on device characteristics, and problems in processes using charged particles have become clear. In other words, it has become clear that the incidence of charged particles damages the substrate to be processed.

Dry etching has been proposed as one method for eliminating damage caused by charged particles.

Further, in etching in which only etching species are supplied to the surface of the substrate to be processed, accurate microfabrication cannot be performed because the etching progresses in the same direction.

Therefore, directional etching using optical excitation has been proposed in which an etching species and a depositing species are simultaneously supplied to the surface of a substrate to be processed and light is irradiated perpendicularly to the substrate to be processed. This principle will be briefly explained with reference to FIG. The substrate to be processed is an etched object 82 on a base substrate 81 as shown in FIG. 8(a).
, and further an etching mask 83 is formed thereon. Etching species and deposition species are supplied to the substrate to be processed, and light is irradiated perpendicularly to the processing surface of the substrate to be processed. Then, as shown in Figure 8(b),
Although deposition occurs on the entire surface of the object to be etched 82, the deposited film 84 is removed on the light irradiated portions and etching progresses, while the deposited film 1184 is not removed on the side walls where no light is irradiated, protecting the etching object from attack by active species. . Therefore, vertical etching can be performed without undercuts.

In principle, etching is carried out using the method described above, but when etching a large-area substrate using this method, there are problems with how to supply and exhaust the etching gas and deposition gas to the substrate. Become.

That is, if the supply direction and the exhaust direction are asymmetrical with respect to the substrate to be processed, the etching rate and etching shape will be uneven on the surface of the substrate to be processed, making it impossible to perform uniform etching. In particular, if the supply direction is asymmetrical, the etching speed and etching shape will be uneven.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to provide an optical excitation method that enables etching of large-area objects with good uniformity and good reproducibility, and that is suitable for the manufacture of semiconductor devices. An object of the present invention is to provide a dry etching device according to the present invention.

[Essentials of invention]

The gist of the present invention is to uniformly supply gas to a substrate to be processed.

That is, the present invention provides a vacuum container for accommodating a substrate to be processed, a means for introducing an etching gas and a deposition gas into the container, a means for exhausting the gas in the container, and a vacuum container for accommodating a substrate to be processed. means for irradiating light perpendicularly to the
In a dry etching apparatus for anisotropically etching a substrate to be processed, the gas introducing means is configured to supply a plurality of gases so that the etching gas and the deposition gas are uniformly supplied to the surface of the substrate to be processed in the container. It is made up of something with holes.

In the apparatus of the present invention, the gases are introduced into the container symmetrically with respect to the surface of the substrate to be processed through a plurality of gas supply holes so that both the etching gas and the deposition gas are uniformly supplied to the surface of the substrate to be processed. be exposed. Similarly, it is more effective to exhaust the air symmetrically or uniformly from the periphery of the substrate to the substrate. Further, the active gas and the deposition gas may be introduced into the container separately, but the active gas and the deposition gas may be mixed outside the container and introduced into the container through the same introduction hole.

In the apparatus of the present invention, the surface of the substrate to be processed must be irradiated with a uniform light intensity. Therefore, the light incident from the direction perpendicular to the surface of the substrate to be processed must not be blocked in its path and non-uniformity of light should not be created on the surface of the substrate to be processed. If the gas supply hole is opaque to incident light, the gas supply hole cannot be placed in the optical path. but,
If the gas supply hole is transparent to light, it can be placed in the optical path. In this case, a gas supply hole can be provided directly above the surface of the substrate to be processed,
It becomes relatively easy to uniformly supply gas to the surface of the substrate to be processed.

Further, in the apparatus of the present invention, deposits may adhere to the inner surface of the container due to the use of a deposition gas.

This deposit also adheres to the gas supply hole, and if this deposit exists, it may impair the reproducibility of etching. To avoid this, there is a method of heating the gas supply hole.

By heating the gas supply holes, fouling is significantly reduced and process reproducibility is improved.

In the present invention, the etching species refers to particles that perform etching, and the deposition species refers to particles that cause deposition on the surface of the substrate to be processed. The generation of these etching and depositing species is caused by electrical discharges, ? Irradiation.

A substance is excited by means such as light irradiation or heat and turned into a gas. Furthermore, there are gases that can serve as etching species or deposition species without being particularly excited, and when these gases are used, no special excitation means is required.

Further, when an excitation means is required to create etching seeds and deposition seeds, the energy for excitation may cause contamination, damage, and other effects on the substrate to be processed. For example, when active species are generated by electric discharge, particles with high kinetic energy generated during the electric discharge may enter the substrate to be processed and cause damage. In order to prevent the excitation means for generating such etching species and deposited species from having a negative effect such as damage on the substrate to be processed, it is necessary to There is a way to separate the area that generates. For example, a gas is excited in a region separate from the substrate to be processed within the same chamber, or an etching species or a deposited species is generated in a separate chamber and transported into the chamber where the substrate to be processed is installed, and then the substrate is exposed to the substrate. The method of supplying

〔Effect of the invention〕

According to the present invention, since photoexcitation etching is used, there is no damage to the substrate to be processed, and anisotropic etching can be performed. Further, since gas can be uniformly supplied to the substrate to be processed, a large-area substrate to be processed can be etched with good uniformity. Further, the process has good reproducibility and etching can be performed with excellent controllability. Therefore, it is extremely effective for future semiconductor device manufacturing processes.

Further, by evacuating the gas symmetrically with respect to the substrate to be processed, the effect of the above-mentioned etching with good uniformity can be further enhanced. Furthermore, if the gas supply hole is heated, it is possible to reduce the adhesion of the deposited film to the gas supply hole, which is also effective from the point of view of maintenance.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic diagram showing a dry etching apparatus according to a first embodiment of the present invention. In the figure, reference numeral 10 denotes a vacuum container, and a sample stage 12 on which a substrate 11 to be processed, such as a semiconductor wafer, is placed is installed at the bottom of the container 10. A light source 13 that emits ultraviolet light or the like is arranged above the container 10.

The light from this light source 13 passes through a light transmission window 14 and is introduced into the container 10, and is irradiated perpendicularly onto the upper surface of the substrate 11 to be processed.

Further, in the upper part of the sample stage 12 in the container 10, the container 10
A first gas introduction pipe 20 having a plurality of gas supply holes 21 for introducing etching gas therein is arranged. This gas introduction tube 20 is connected to a discharge tube 24 that passes through a waveguide 23 connected to a microwave electric vA22. The etching gas passes through the discharge tube 24, is activated by discharge, and is introduced into the container 10 through the gas supply hole 21 of the gas introduction tube 20. Further, a second gas introduction pipe 30 is provided between the gas introduction pipe 20 and the sample stage 12 and is provided with a plurality of gas supply holes 31 for introducing a deposition gas. A pipe 32 is connected to this gas introduction pipe 30. Also, container 1
A plurality of gas exhaust ports 40 are provided at the bottom of the container 10 to exhaust the gas inside the container 10.

Here, the first gas introduction pipe 20 is formed into an annular shape as shown in FIG. 2, and a plurality of gas supply holes 21 are provided at equal intervals inside the first gas introduction pipe 20. As a result, the gas supply hole 21
The gas supplied from the substrate 11 is uniformly supplied to the substrate 11 as shown in FIG. In general, the second gas introduction pipe 30 is also the same as the first gas introduction pipe 2.
Like 0, it is formed in an annular shape. In addition, gas introduction pipe 2
The outer diameter of 0.30 is larger than the outer diameter of the substrate 11 to be processed so as not to interfere with the light irradiation.

On the other hand, as shown in FIG.
Individually formed. These exhaust ports 40 (401, ~
, 40g), the gas in the container 10 is transferred to the substrate 1 to be processed.
The air is evenly exhausted in a direction symmetrical to the top surface of the air conditioner 1.

With such a configuration, the etching gas containing a halogen element, etc. passes through the discharge tube 24, and the etching species, which are active species thereof, are introduced into the container 10 from the gas supply hole 21 of the first gas introduction tube 20. , are uniformly supplied onto the upper surface of the substrate 11 to be processed. On the other hand, the deposition gas passes through the pipe 32 and the second
The gas is introduced into the container 10 through the gas supply hole 31 of the gas introduction pipe 30, and is uniformly supplied to the upper surface of the substrate 11 to be processed. This deposition gas is activated by the etching species and becomes a deposition species. Incidentally, like the etching gas, the deposition gas may also be activated by electric discharge or the like outside the container 10, and the activated species, which is the deposition species, may be introduced into the container 10 from the second gas introduction pipe 30. good. Further, the light from the light source 13 is uniformly irradiated perpendicularly to the substrate 11 without being blocked by the gas introduction pipe 20, 30, or the like.

Therefore, when the substrate 11 to be processed has the structure shown in FIG. 8(a), the surface of the substrate 11 to be processed has 1 t
A deposited film is formed by the Ila gas, and the deposited film other than the etched sidewall portion is removed by light irradiation. The portion where the deposited film has been removed is etched by an etching species. In other words, due to the competitive reaction between deposition and etching, anisotropic etching can be performed as shown in FIG. 8(1)).

And in this case, he is here! ! Since gas is uniformly supplied to the substrate 11, the etching described above can be performed uniformly, and even a large area of the substrate to be processed can be anisotropically etched with good uniformity. Furthermore, since the gas is activated in a region separate from the inside of the container 10, there is no problem such as damage to the substrate 11 to be processed due to electrical charges.

FIG. 5 shows the main structure of a second embodiment of the present invention, in which (a) is a cross-sectional view and (b) is a vertical cross-sectional view. In addition,
Components that are the same as those in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the first embodiment described above as follows:
As a means for introducing the etching gas, a gas introduction port is provided on the surface of the container W1. That is, four relatively large gas introduction ports 50 are provided in the side wall of the container 10 symmetrically with respect to the substrate 11 to be processed. Even in this case, the gas is uniformly supplied to the substrate 11 to be processed. Furthermore, although gas is supplied horizontally in the figure, it may be inclined upward or downward in consideration of the uniformity of the gas flow.

As the means for introducing the deposition gas, a gas introduction port may be provided in the side wall of the container 10 as described above, or an annular gas introduction pipe may be further provided in the same manner as described above.

Further, as shown in FIG. 6, a gas inlet 60 for introducing a deposition gas is connected to a gas inlet 50 for introducing an etching gas, and after mixing these gases in advance, the container 1 is
It may be introduced within 0.

Even with such a configuration, gas can be uniformly supplied to the substrate 11 to be processed. Therefore, the same effects as in the first embodiment can be obtained.

FIG. 7 shows the main structure of a third embodiment of the present invention, in which (a) is a cross-sectional view and (b) is a plan view. Note that the same parts as in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the first embodiment described above as follows:
A disc-shaped container is used as a gas introduction means, and the container is heated. That is, above the sample stage 12 in the container 10, instead of the first gas introduction pipe 20, a hollow disk-shaped gas introduction container 70 is arranged. This container 70 is made of a material that is transparent to the light from the light source 13, and has a ?? ! A number of gas supply holes 71 are equally provided. The etching gas (or etching species) blown out from these gas supply holes 77 is uniformly supplied to the substrate 11 to be processed.

A cooling pipe 75 made of a material transparent to the light is attached to the upper surface of the gas introduction container 70.

The gas introduction container 70 is cooled by flowing transparent cooling gas into the cooling pipe 75. Note that the introduction means for the deposition gas may be the same as described above, or the second gas introduction pipe 30 may be provided.

Even with such a configuration, gas can be uniformly supplied to the substrate 11 to be processed, so that the same effects as in the first embodiment can be obtained. In addition, the gas introduction container 70
Since the container 70 is cooled, the amount of deposited film adhering to the container 70 can be extremely reduced, and there are also advantages such as the reduction in maintenance for 1 ull.

Note that the present invention is not limited to the embodiments described above. For example, the means for activating the etching gas and the deposition gas is not limited to electric discharge, and electron irradiation, light irradiation, or heat may also be used. In particular, when using light irradiation, it becomes possible to activate the gas within a vacuum container containing the substrate to be processed. Further, the gas in the vacuum container does not necessarily need to be exhausted at a speed symmetrical to the substrate to be processed. In other words, it has been confirmed that simply supplying gas uniformly to the processing surface of the substrate to be processed using the gas introducing means of the present invention has a sufficient effect. Further, the types of etching gas and deposition gas may be changed as appropriate depending on the material to be etched. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a dry etching apparatus according to a first embodiment of the present invention, FIG. 2 is a plan view showing the structure of a gas introduction pipe used in the above apparatus, and FIG. FIG. 4 is a schematic diagram for explaining the gas supply action; FIG. 4 is a schematic diagram showing a gas exhaust port provided in the above device; FIG. FIG. 6 is a cross-sectional view showing a modification of the second embodiment, FIG. 7 is a cross-sectional view and a plan view showing the main structure of the third embodiment of the present invention, and FIG. 8 is a diagram showing the problems of the conventional method. It is a sectional view for explanation. 10... Vacuum container, 11... Substrate to be processed, 12...
- Sample stage, 13... Light source, 14... Light transmission window, 20
．． 30... Gas introduction pipe, 21.31.71... Gas supply hole, 22... Microwave ii source, 23... Waveguide, 24... Discharge tube, 40... Gas exhaust Mouth, 50.
60...Gas introduction port, 70...Gas introduction container. Applicant's representative Patent attorney Takehiko Suzue Figure 3 Figure 4 Figure 6 (a) Figure 5 (a) (b) Figure 8

Claims (8)

[Claims] (1) A vacuum container for accommodating the substrate to be processed, a means for introducing an etching gas and a deposition gas into the container, a means for exhausting the gas in the container, and a vacuum container for accommodating the processing surface of the substrate to be processed. In the dry etching apparatus, the dry etching apparatus includes a means for vertically irradiating light and performs anisotropic etching on a substrate to be processed, wherein the gas introduction means allows the etching gas and the deposition gas to reach the surface of the substrate to be processed in the container. A dry etching apparatus characterized by having a plurality of gas supply holes for uniform gas supply. (2) The etching gas and the deposition gas are discharged,
The dry etching apparatus according to claim 1, wherein the dry etching apparatus is activated by electron irradiation, light irradiation, or heat. (3) The dry etching according to claim 2, wherein the etching gas and the deposition gas are activated in a region separated from a region where the substrate to be processed is placed. Device. (4) The dry etching apparatus according to claim 1, wherein the etching gas and the deposition gas are introduced into the container through independently provided gas supply holes. (5) The dry etching apparatus according to claim 1, wherein the etching gas and the deposition gas are mixed outside the container and introduced into the container through the same gas supply hole. (6) The dry etching apparatus according to claim 1, wherein the gas supply hole is made of a material through which light irradiated from above passes. (7) The dry etching apparatus according to claim 1, wherein the gas supply hole is provided with means for heating the gas supply hole. (8) The dry etching apparatus according to claim 1, wherein the gas exhaust means exhausts gas from around the sample stage on which the substrate to be processed is placed at a uniform or symmetrical exhaust speed. .