JPS61281881A - Dry etching device - Google Patents

Abstract

PURPOSE:To enable prevention of the generation of electric discharge and the uniform etching by disposing a gas introducing means provided with plural gas introducing holes to the position opposing to a base body to be treated and forming the peripheries of the holes of a non-metal. CONSTITUTION:This dry etching device is constituted by using the inside wall of a vacuum vessel 11 having a gas discharge port 31 and an electrode 13 to constitute a pair of electrodes, connecting the electrodes to a high-frequency power source 15 via a matching circuit, mounting an Si substrate 18 which is the base body to be treated to the electrode 13 and disposing further the gas introducing part 21 provided with the plural gas introducing holes 20 to the position opposing to the substrate 18. The peripheries of the holes 20 are formed of C or material contg. C or non-metal such as SiO2, Si3N4 or Al2O3. The uniform etching is thus enabled without generating electric discharge near the holes 20 in the stage of etching the substrate 18 by introducing an etching gas into the vessel from the above-mentioned gas introducing part 21 and impressing high-frequency electric power to the electrode 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a dry etching apparatus used in the manufacture of semiconductor integrated circuits and the like.

[Technical background of the invention and its problems]

In recent years, with the miniaturization of semiconductor integrated circuits, various etching techniques have been developed. Among these, dry etching apparatuses that utilize reactive ion etching are attracting attention because they can achieve vertical etching along the ask.

In this device, a gas containing a halogen element is introduced into a vacuum container equipped with a pair of parallel plate electrodes, high frequency power is applied between the electrodes to discharge the gas, and the plasma generated by this discharge is utilized. The treated substrate is etched. In other words, the gas introduced into the container is ionized,
This method realizes vertical etching along the mask by bombarding the surface of the substrate to be processed with ions accelerated along the ion sheath formed on the electrode surface and activating the excited bicomponent acid. .

However, this type of device has the following problems. That is, conventionally, as a means for introducing gas into a vacuum container, a gas introduction mechanism is used, which has a plurality of gas introduction holes at a position facing the substrate to be processed, and this gas introduction mechanism is generally made of metal. ing. For this reason, there is a possibility that discharge will be concentrated near the gas introduction hole of the gas introduction mechanism made of a metal material. When the discharge concentrates near the gas introduction hole, the ion density near the gas introduction hole increases, resulting in non-uniform etching of the surface of the substrate to be processed. In addition, since the metal material is sputtered by this discharge and adheres to the surface of the substrate to be processed, there have been problems such as inconvenience when a device is manufactured.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to provide a dry etching device that can prevent discharge from occurring near the gas introduction hole and can perform uniform etching without metal contamination. Our goal is to provide the following.

[Summary of the invention]

The gist of the present invention is to use a non-metal as the material near the gas introduction hole in order to prevent electrical discharge near the gas introduction hole.

That is, the present invention provides a vacuum container equipped with a pair of electrodes therein;
The apparatus includes a gas introduction means for introducing gas into the container, a gas exhaust means for exhausting the gas in the container, and a means for supplying high frequency power between the electrodes, and generates an electric discharge between the electrodes. In the dry etching apparatus for etching a substrate to be processed disposed between the electrodes, the gas introduction means is constituted by a gas introduction mechanism provided with a plurality of gas introduction holes at a position facing the substrate to be processed, and at least The periphery of these holes is made of non-metal.

(Effects of the Invention) According to the present invention, since the vicinity of the gas introduction hole is formed of a non-metallic material, it is possible to prevent electric discharge in the vicinity of this hole. Therefore, uneven etching can be prevented and the substrate to be processed can be etched uniformly. moreover,
Since no discharge occurs near the gas introduction hole, the material near the hole is not sputtered, and the metal (
It also has the advantage of being able to prevent contamination (and non-metallic).

[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 an embodiment of the present invention. In the figure, 11 is a vacuum container, and an electrode 1 is connected to the upper part of the container 11 via an insulator 12.
3 is fixed. The container 11 is grounded, and high frequency power (for example, 13.56 M lb ) is applied to the electrode 13 from a high frequency power source 15 via a matching circuit 14 . As a result, a part of the inner wall of the container 11 acts as a counter electrode to the electrode 13, and a discharge is generated between these electrodes. In addition, a water cooling pipe 1 is provided above the electrode 13.
6.17 is provided, and the electrode 13 is cooled by the water-cooled pipe 16.17. Note that the substrate 18 to be processed to be subjected to etching is fixed to the lower surface of the electrode 13.

On the other hand, in the lower part of the container 11, a gas introduction part 21 having a plurality of gas outlet holes 20 is arranged opposite to the electrode 13. As shown in FIG. 2, the gas introduction section 21 is a hollow disc with a plurality of holes 20 evenly provided on its entire surface, and is made of a non-metal such as carbon. Gas introduction part 21
is connected to one end of a metal gas introduction pipe 22, and the other end of this gas introduction pipe 22 is led out of the container 11.

The other end of the gas introduction pipe 22 is connected to a gate valve 23. It is connected to a gas cylinder (not shown) or the like via a gas introduction pipe 24 and a mass flow controller 25.

From the gas introduction hole 20, a mixed gas of Cλ2/CHF3, for example, is blown out toward the substrate 18 as an etching gas.

Further, an exhaust port 31 is provided at the bottom of the container 11, and this exhaust port 31 is connected to a gate valve 32.degree. liquid nitrogen trap 33. It is connected to an oil rotary pump 35 via a gate valve 34. The inside of the container 11 is evacuated by an oil rotary pump 35 equipped with a liquid nitrogen trap 33.

Next, an example of etching using this apparatus having the above configuration will be explained.

As the substrate 18 to be processed, a Si substrate in which a mask pattern of an SiO2 film is formed on single crystal Si is used.
was fixed to the lower surface of the electrode 13 in the container 11. After opening the gate valves 32 and 34 to exhaust the inside of the container 11, CJ2218 [ae/1n], CHF32
Cd/i+in] is introduced into the container 11 through the gas introduction hole 20, and the gate valve 32 is adjusted so that the pressure inside the container 11 becomes 10 [Pal. Next, high frequency power supply 1
5 was turned on, high frequency discharge was generated within the container 11, and etching was performed.

As a result, similar to the conventional device, the 3i substrate 18 is
Selective etching was possible according to the two masks. In this case, no discharge occurred near the gas introduction hole 20, and it was possible to perform etching uniformly.

As described above, according to this embodiment, since the gas introduction part 21 is made of a non-metal such as carbon, it is possible to prevent electrical discharge from occurring around the gas introduction hole 20 during etching. Therefore, etching can be performed on the Sil plate 1 and the sheet metal 8. Moreover, since no discharge occurs around the gas introduction hole 20, it is possible to prevent the area around the gas introduction hole 20 from being sputtered and becoming a source of contamination of the 3i substrate 18. According to experiments conducted by the present inventors, after etching, surface analysis of the 81 substrate 18 using Auger electron spectroscopy revealed that there was no metal contamination.
There was also no adhesion of the non-metal used in No. 1. From this,
The effect of using a non-metal such as carbon for the gas introduction part 21 is obvious.

FIG. 3 is a schematic diagram showing a dry etching apparatus according to another embodiment of the present invention. 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 previously described embodiments in the structure of the gas introduction section, and is otherwise completely similar to the previous embodiments.

That is, in this embodiment, an annular gas introduction part 41 is arranged below the electrode 13 and connected to the gas introduction pipe 22. Further, the gas introduction part 41 has a plurality of gas introduction holes 40 provided in its upper part as shown in FIG. 4, and is made of a non-metal such as carbon like the gas introduction part 21.

Even with such a structure, it is possible to prevent discharge from occurring around the gas introduction hole 40.

Therefore, the same effects as in the previous embodiment can be obtained.

Note that the present invention is not limited to the embodiments described above. For example, the non-metal forming the gas introduction part may be 5iOz instead of carbon.

Si3N4. It is possible to use an insulator such as A.degree. C. 203. Further, the entire gas introduction part does not necessarily need to be made of nonmetal, and only the periphery of the gas introduction hole may be made of nonmetal. Furthermore, the entire gas introduction mechanism including the gas introduction section, the gas introduction pipe, etc. may be made of non-metal. Furthermore, instead of using the wall surface of the container as one electrode, a new electrode may be provided at a position facing the electrode on which the sample is placed. In general, conditions such as the type and flow rate of the gas introduced into the container may be adjusted as appropriate depending on the substrate 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 one embodiment of the present invention, FIG. 2 is a plan view showing the structure of a gas introduction part used in the above-mentioned apparatus, and FIG. 3 is a diagram according to another embodiment. FIG. 4 is a schematic diagram showing the dry etching apparatus, and FIG. 4 is a plan view showing the structure of the gas introduction section used in the apparatus of the other embodiment. DESCRIPTION OF SYMBOLS 11... Vacuum container, 12... Insulator, 13... Electrode, 14... Matching circuit, 15... High frequency power supply, 16° 17... Water cooling tube, 18... 3i board ( Substrate to be processed), 20.40... Gas introduction hole, 21.41.
...Gas introduction part, 22.24...Gas introduction pipe, 23.
32.34... Gate valve, 25... Mass flow controller, 31... Gas exhaust port, 33... Liquid nitrogen trap, 35... Oil rotary pump. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 4 Figure 3

Claims (4)

[Claims] (1) A vacuum container equipped with a pair of electrodes inside, a gas introduction means for introducing gas into the container, a gas exhaust means for exhausting the gas in the container, and supplying high-frequency power between the electrodes. In the dry etching apparatus, the gas introduction means introduces a plurality of gases into positions facing the processing target substrate by generating a discharge between the electrodes and etching the processing target substrate disposed between the electrodes. What is claimed is: 1. A dry etching apparatus characterized by having holes, and at least the periphery of these holes being made of a non-metal. (2) The dry etching apparatus according to claim 1, wherein carbon or a material containing at least carbon is used as the nonmetal. (3) As the non-metal, SiO_2, Si_3N_4
The dry etching apparatus according to claim 1, characterized in that Al_2O_3 is used. (4) The dry etching apparatus according to claim 1, wherein one of the electrodes is formed on an inner wall surface of the vacuum container.