JPH01218025A - Plasma etching apparatus - Google Patents

Abstract

PURPOSE:To prevent a reaction gas from being liquefied by installing a structure used to heat a reaction gas introduction port and a reaction gas introduction pipe near the introduction port in order to locally heat the reaction gas flowing inside. CONSTITUTION:A heating structure 12 is arranged and installed at a gas introduction port 6 and around a gas introduction pipe 7 near it. When a reaction gas, e.g., CCl4, is introduced into a chamber 1, i.e., when the reaction gas CCl4 flows inside the introduction pipe 7 and flows into the chamber 1 from the gas introduction port 6, the gas is liquefied on a substrate 4 when it is introduced into the chamber 1 at room temperature. When the reaction gas CCl4 is always heated up to 60 deg.C by using the structure 12, it is possible to prevent the reaction gas CCl4 from being liquefied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plasma etching apparatus for a sample such as a semiconductor substrate.

[Conventional technology]

The structure of a conventional plasma etching apparatus of this type, for example a parallel plate electrode type plasma etching apparatus, will be explained with reference to FIG. That is, in FIG. 4, an upper electrode (2) and a lower electrode (3) serving as a sample stage whose temperature is controlled by an electrode temperature control vibrator QO are disposed in a chamber (1). and the lower electrode (3)
With the sample to be etched (4) such as a semiconductor substrate placed on top, reactant gas such as CF4+02 is introduced through the flow rate controller (9), valve (8), gas inlet pipe (7), and gas inlet. (6) into the chamber (1), and at the same time, the gas pressure is kept constant while being appropriately exhausted from the exhaust port (b), and an RF power source ( 5), a high frequency is applied to generate gas plasma, and a sample (such as a semiconductor substrate) placed on the lower electrode (3) is heated.
4) The surface is etched.

[Problem to be solved by the invention]

In the conventional plasma etching apparatus with this configuration, when a reactant gas with a lower vapor pressure is introduced into the chamber (1) through the reactant gas inlet (6), the temperature of the gas decreases due to adiabatic expansion, and the reaction The gas liquefies and falls onto the surface of the sample (4), and the sample (4) is contaminated by the liquefied reaction gas adhering to the surface of the sample (4), resulting in poor etching uniformity and pattern defects. There were some inconveniences such as

This invention was made in order to solve the above-mentioned problems, and it does not cause liquefaction of the reaction gas. Therefore, contamination of the sample by the liquefied reaction gas, non-uniformity of etching, pattern defects due to etching, etc. occur. The purpose of this invention is to obtain a plasma etching device that does not have a conventional plasma etching system.

[Means to solve the problem]

The plasma etching apparatus according to the present invention is provided with a mechanism for heating a reactive gas inlet and a reactive gas inlet tube near the inlet, and locally heats the reactive gas flowing therethrough to raise the temperature of the reactive gas. , to prevent the reaction gas from liquefying.

[Effect]

In the plasma etching apparatus of this invention, the moment the gas flows into the low-pressure chamber through the narrow gas introduction pipe, it undergoes adiabatic expansion, similar to conventional plasma etching apparatus, but the gas is Since the gas is heated, even if the gas undergoes a temperature drop due to adiabatic expansion, the gas temperature remains higher than the temperature at which liquefaction occurs, so liquefaction of the gas does not occur within the chamber.

[Embodiments of the invention]

Hereinafter, one embodiment of a plasma etching apparatus according to the present invention will be described with reference to FIG.

In FIG. 1, the same reference numerals as in FIG. 4 indicate the same or corresponding parts, and in this embodiment, a heating mechanism (2) is installed around the gas inlet (6) and the gas inlet pipe (7) in its vicinity. This is what was installed.

Furthermore, the heating mechanism (6) will be explained in more detail with reference to FIG. 2. A heating wire (6) is arranged on the gas introduction pipe (7), and a voltage can be applied to both ends of the heating wire from a heating power source (143).

Here, the operation of this embodiment is such that when a reactant gas, for example CCI, is introduced into the chamber (1), the reactant gas CC
When I flows through the gas introduction pipe (7) and flows into the chamber (1) from the gas introduction port (6), the temperature is at room temperature (25°C).
If it is introduced into the chamber as it is, it will liquefy on the substrate and cause a problem, but the heating mechanism (6) always keeps the reactant gas CCl4
By heating it to 60°C, it no longer liquefies.

In the above embodiment, the heating mechanism (2) is equipped with a heating wire (to) inside the introduction pipe (7) to heat the gas by resistance heating, as shown in Fig. 2. Alternatively, the heating wire may be insulated and buried in the pipe wall.

In addition to resistance heating, it is also possible to heat the gas flowing inside the tube by immersing the spiral gas introduction tube (7) in hot water as shown in Figure 3, or by using an IR lamp. The gas may also be heated.

〔Effect of the invention〕

This invention adds a heating mechanism to the gas introduction part of the conventional plasma etching apparatus, which makes it possible to raise the temperature of the reaction gas, prevent the reaction gas from liquefying due to adiabatic expansion, and prevent the liquefaction of the reaction gas from adhering to the sample. Contamination of the sample by reactive gas, such as pattern defects that may occur during etching of semiconductor substrates for LSI manufacturing, etc., can be effectively prevented, the etching characteristics can be improved, and practical application is easy.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a plasma etching apparatus according to an embodiment of the present invention, FIG. 4 is a schematic configuration diagram showing a conventional plasma etching apparatus, and FIGS. 2 and 3 are the heating mechanism shown in FIG. 1. This figure shows a schematic diagram of two other examples of QJ. l...chamber, 2...upper part! Pole, 3... Lower electrode that also serves as a sample stage, 4... Sample, 5... High frequency power supply, 6... Gas inlet, 7... Gas inlet tube, 8...
- Valve, 9... Flow rate control device, 10... Electrode temperature control pipe, 11... Exhaust port, ν... Heating mechanism, 13
...Heating wire, 14...Heating power supply. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In an apparatus for plasma etching a sample material such as a semiconductor substrate placed on a sample stage in a chamber using a reactive gas, a mechanism for heating an inlet for introducing the reactive gas into the chamber and a reactive gas inlet tube near the inlet is provided. What is claimed is: 1. A plasma etching apparatus characterized in that the plasma etching apparatus is capable of preventing a liquefaction phenomenon of a reaction gas that occurs when the reaction gas is introduced into a chamber.