JPH04142032A - Apparatus and method for etching - Google Patents

Abstract

PURPOSE:To execute an etching operation whose selectivity is high in an etching shape provided with directivity and without causing damage by a method wherein a chemical-liquid vapor extracted from a chemical-liquid vapor generation source is guided, as charged particles, to the surface of a substrate by using an electron application means and the energy of the charged particles is controlled by a voltage applied to the substrate. CONSTITUTION:A chemical-liquid vapor which has been produced in a chemical- liquid vapor generation source 5 is extracted; the vapor is guided to a traveling path 7; an electron application means 4 by which electrons are applied to the chemical-liquid vapor is installed on the traveling path 7; charged particles formed by the electron application means are guided to the inside of a reaction chamber 3. The temperature of the chemical-liquid vapor generation source 5 and that of a substrate S are controlled. Thereby, the etching rate of the substrate S or a film on the substrate S is controlled, a voltage applied to the substrate S is controlled and an etching direction is controlled. Thereby, it is possible to execute an etching operation by which the direction of an etching shape can be controlled easily, which does not cause damage and whose etching selectivity is high.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an etching apparatus and an etching method.

<Prior Art> FIG. 2 is a block diagram of a conventional wet etching apparatus.

A substrate sample 1 is placed in an HF aqueous solution 12 containing HF (butyric acid).
Etching is carried out by dipping 1.

Further, FIG. 3 is a configuration diagram of a plasma etching apparatus.

This device consists of two parallel plate electrodes 13.
．． A high-frequency electric field is applied between 14 and a reactive gas 16 introduced during this period to generate plasma, which is guided to a substrate 11 placed on a sample stage 15 to perform plasma etching.

<Problem to be solved by the invention> By the way, according to conventional etching equipment, it is difficult to control the directionality of reactive species in wet etching.
There was a problem in that the etched shape was isotropic, making it unsuitable for microfabrication.

In addition, dry etching has the problem of whether it is possible to control the directionality of the etched shape, or that it causes damage such as charge-up, contamination, and crystal defects, which deteriorates the characteristics of the semiconductor element.

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide an etching apparatus and an etching method that allow easy direction control of etched shapes, do not cause damage, and have high etching selectivity.

Means for Solving the Problems> The structure for achieving the above object will be explained with reference to FIG. 1 corresponding to the embodiment. An electron attaching means 4 for attaching electrons to the chemical vapor is provided on the advancing path 7, and the charged particles formed by the electron attaching means are transferred to the reaction chamber. It is characterized by being configured to lead within 3.

Furthermore, the etching method of the present invention uses the above-mentioned apparatus to control the etching rate of the substrate or a film on the substrate by controlling the chemical vapor generation source and the temperature of the substrate, as well as controlling the voltage applied to the substrate. It is characterized by controlling the etching direction.

<Operation> The chemical vapor drawn from the chemical vapor generation source becomes charged particles by the electron attachment means and is guided to the substrate surface, and the energy of the charged particles is controlled by the voltage applied to the substrate, thereby changing the directionality. It has a firm etched shape.

Furthermore, the etching rate can be adjusted by controlling the temperature of the chemical vapor source and the substrate.

Furthermore, since chemical vapor is used as the etchant, the etching mechanism is similar to wet etching, and the etching is highly selective to the mask material and underlying material.

<Example> FIG. 1 is a block diagram of main parts of an embodiment of the apparatus of the present invention.

An etching liquid 6, such as an HF aqueous solution, is stored in the chemical vapor generation source 5, and its temperature is regulated by a heater or the like (not shown). This affects the amount of steam produced,
This is a factor that ultimately controls the etching rate.

The generated vapor is drawn out by a pressure difference between the reaction chamber 3 and the reaction chamber 3, which is reduced in pressure by an exhaust pump (not shown), and passes through the electron attachment means 4 provided on the path 7 of the chemical vapor. At this time, electrons emitted by heat or an electric field attach to the vapor particles and become electrically charged.

These charged particles are subsequently guided into the reaction chamber 3 by the differential pressure, reach the surface of the substrate S placed on the sample stage 2, and etch the substrate or the film formed on the substrate. On this occasion,
The etching shape of the substrate S is controlled by changing the positive or negative DC voltage as necessary using the DC bias power supply 1.

Note that the reaction product is easily vaporized because it is under reduced pressure, leaves the surface of the substrate S, and is exhausted.

Furthermore, by controlling the substrate temperature using a temperature control function (heater or coolant), the reaction rate between the etchant and the material to be etched can be changed.

With the above configuration, it is possible to perform anisotropic etching while maintaining the high selectivity and damage-free characteristics of wet etching.

Next, an embodiment of the method of the present invention will be described using the etching apparatus shown in FIG.

In this example, a case will be described in which a silicon oxide film on a silicon substrate having a resist pattern is etched.

First, a hydrofluoric acid aqueous solution is put into the chemical vapor generation source 5, and
Set to ~50°C. Next, in the electron attaching means 4, a tungsten filament is used, and electrons are emitted by field emission. The chemical liquid vapor generated from the chemical liquid vapor generation source 5 becomes charged particles due to the attachment of electrons thereto.

On the other hand, the pressure inside the reaction chamber 3 is reduced to 1 to 10 Torr, and the temperature of the sample stage 2 is controlled within the range of 20 to 50°C using a cooling medium.
It is set within the range of 0■.

As a result, charged particles are transferred to the sample stage 2 in the reaction chamber 3.
A potential is given by the bias applied to the substrate S, and it has directionality with respect to the substrate S.

Therefore, the present invention does not have the characteristics of wet etching, and allows etching with directionality.

The above description has been given of the case where a silicon oxide film on a silicon substrate is etched, but the present invention is not limited to this, and includes etching films deposited or coated on a substrate, such as polysilicon formed on a substrate, etc. Of course, the present invention can also be applied to any other apparatus and method for etching the substrate itself.

<Effects of the Invention> According to the etching apparatus of the present invention, the chemical vapor drawn out from the chemical vapor generation source by the pressure difference becomes charged particles by the electron attachment means, and is guided to the substrate surface, and at this time, the energy of the charged particles is Since it is controlled by the voltage applied to the substrate, the etched shape has directionality.

Furthermore, since the etching method of the present invention has the characteristics of both dry etching and wet etching,
Damageless and highly selective etching becomes possible.

Furthermore, since the temperature of the chemical vapor source and the substrate can be easily controlled, the etching rate can be adjusted as appropriate.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of essential parts of an embodiment of the apparatus of the present invention, FIG. 2 is a block diagram of a conventional wet etching apparatus, and FIG. 3 is a block diagram of a dry etching apparatus. 2...Sample stand 3...Reaction chamber 4...Electron attachment means 5...Chemical vapor generation source 6...Etching liquid...Progress path S...Substrate

Claims (2)

[Claims] (1) In an apparatus for etching a substrate or a film on a substrate by drawing out chemical vapor generated in a chemical vapor generation source and guiding the vapor to the surface of a substrate provided in a reaction chamber, An electron attaching means for attaching electrons to the chemical vapor is provided on the path of the chemical vapor drawn from the chamber, and charged particles formed by the electron attaching means are guided into the reaction chamber. Etching equipment. (2) Using the etching apparatus according to claim 1, the etching rate of the substrate or a film on the substrate is controlled by controlling the temperature of the chemical vapor generation source and the substrate, and the etching rate of the substrate or the film on the substrate is controlled. An etching method characterized by controlling the etching direction by controlling the voltage applied.