JP2003151952A - Method of dry etching - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry etching method, using a fluorine-based etching gas, especially one which uses ICP (inductively-coupled plasma) type low-pressure, high-density plasma, for effectively preventing unwanted particles without decreasing the productivity. SOLUTION: For each treatment of a prescribed number of substrates, oxygen (O2 ) is fed in an etching chamber 11 and oxygen plasma is generated, while the inside of the etching chamber is held in a vacuum state. In the etching treatment of the substrate, a deposited layer of AlF3 generated at the inner wall of the vacuum chamber 11 is partly removed due to the sputtering effect of oxygen plasma ions. At the same time, the remaining deposited layer of AlF3 is changed in quality by the oxygen plasma and flaking is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching method, and more particularly to a dry etching method capable of suppressing generation of particles in a chamber.

[0002]

2. Description of the Related Art In flat panel display devices such as liquid crystal display devices and organic EL display devices, especially in the production of array substrates, dry etching is used because of the need for microfabrication as in semiconductor devices using silicon wafers. It's coming.

By the way, in such a dry etching apparatus, the inner wall of the vacuum chamber is formed of alumina (Al ₂ O ₃ ) which is excellent in discharge resistance, but when a fluorine-based etching gas is used, the chamber is There is a problem that Al constituting the material reacts with fluorine as an etching gas to generate AlF ₃ (aluminum fluoride), which is deposited in the chamber and peels off to generate particles, which causes a defect.

[0004]

As a method for solving such a problem, it is conceivable to manually clean the inside of the chamber for each processing of a plurality of sheets, but the workability is poor and
This causes a significant decrease in productivity.

The present invention has been made in view of the above technical problems, and provides a dry etching method capable of effectively preventing the generation of undesired particles and not impairing the productivity. Is intended.

[0006]

A dry etching method according to the present invention is a dry etching method in which a substrate to be processed is placed on a stage of a vacuum chamber and the substrate to be processed is dry-etched with a fluorine-based etching gas. It is characterized in that an oxygen discharge is generated in the vacuum chamber after processing a predetermined number of substrates to be processed.

A more detailed description will be given below with reference to embodiments of the present invention.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dry etching method according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a dry etching apparatus for carrying out the cleaning method according to this embodiment.

This dry etching apparatus is equipped with an ICP (Ind
uctively coupled plasma etching) is a low-pressure high-density plasma etcher.
The dry etching apparatus shown in FIG. 1 includes a vacuum chamber 11 provided with a gas introduction line and a gas exhaust line (not shown), a stage 13 arranged in the vacuum chamber 11 and connected to a bias power source 21, and this stage. A quartz plate 15 arranged to face 13 and an antenna unit 17 connected to a high frequency power source 31 on the quartz plate 15 are provided.

The inner wall of the vacuum chamber 11 is made of alumina in consideration of etching resistance.

Usually, on a stage 13 arranged in the vacuum chamber 11 of such a dry etching apparatus, for example, a 550 × 650 mm glass substrate for a liquid crystal display device is arranged, and a polycrystalline silicon film or the like thereon is arranged. The semi-solid layer, Al alloy and
A wiring material such as MoW alloy, and further an oxide film, a nitride film, etc. functioning as a passivation film are patterned into a predetermined shape by a dry etching process.

Here, for example, when a fluorine-based gas is used as the etching gas, Al constituting the chamber material reacts with fluorine of the etching gas in the vacuum chamber 11 to generate Al.
It produces F ₃ , which deposits in the chamber 11. Then, the unnecessary deposits are peeled off to generate particles, which causes defects.

Therefore, in this embodiment, for example, every time 10 substrates are processed, O ₂ plasma is generated with the substrate to be processed removed from the stage 13.

This allows the chamber 11 to be treated as unnecessary deposits.
A part of AlF ₃ attached to the inner wall is separated from the inner wall of the chamber 11 by the sputtering effect of plasma ions and is exhausted to the outside of the chamber 11.

In addition, as an unnecessary deposit on the inner wall of the chamber 11.
Other AlF adhered_ThreeIs injected with oxygen to improve the film quality.
It It is an unnecessary deposit that has been improved in film quality by oxygen injection.
AlF _ThreeIs less likely to come off the inner wall of the chamber.
Due to the
It is prevented from becoming a tickle.

As described above, according to this embodiment, the chamber is not exposed to the atmosphere, and the O ₂ plasma treatment can be automatically performed periodically by preprogramming, so that the productivity is improved. It is possible to effectively prevent the generation of particles without significantly damaging the particles.

The interval of the O ₂ plasma treatment is appropriately changed depending on the etching time or the like, and it is desirable to perform the O ₂ plasma treatment before the generation of particles. In addition, a dummy substrate may be placed on the stage 13 for this process.

In this embodiment, the ICP type low-pressure high-density plasma etcher has been described as an example, but the present invention is not limited to the above apparatus.

[0020]

According to the present invention, it is possible to provide a dry etching method capable of effectively preventing the generation of undesired particles and without impairing the productivity.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a dry etching apparatus according to an embodiment of the present invention.

[Explanation of symbols]

11 vacuum chamber 13 stages 17 High frequency power supply

Claims (3)

[Claims] 1. A dry etching method in which a substrate to be processed is placed on a stage of a vacuum chamber, and the substrate to be processed is dry-etched with a fluorine-based etching gas. A dry etching method characterized in that an oxygen discharge is generated in a chamber. 2. The dry etching method according to claim 1, wherein the deposit in the vacuum chamber is modified by the oxygen discharge treatment. 3. The dry etching method according to claim 2, wherein the deposit is AlF ₃ and the oxygen content is increased by the oxygen discharge treatment.