JP2602358B2 - Plasma etching equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma etching apparatus used for manufacturing a semiconductor device, and more particularly to an internal structure of a reaction chamber.

[Prior art] Conventionally, a plasma etching apparatus used for manufacturing a semiconductor device has a reaction chamber kept at a vacuum by a vacuum pump,
A high-frequency voltage is applied to a counter electrode disposed in the reaction chamber, and the semiconductor substrate held on the lower electrode is etched by excitation or ionization of the introduced gas.

[Problems to be solved by the invention]

In this conventional plasma etching apparatus, a high-frequency voltage is applied to a counter electrode disposed in a reaction chamber, and the introduced gas is excited or ionized to perform the etching process. Since the positive and negative charges are switched in a short time, the charge particles do not accumulate on the semiconductor substrate, but the charge particles accumulate on the insulating film of the semiconductor substrate when the high frequency is cut off at the end of etching. However, there is a problem in that the lower thin film is damaged.

An object of the present invention is to provide a plasma etching apparatus in which a secondary electron generating mechanism is provided in a reaction chamber to neutralize charge particles accumulated on a semiconductor substrate, thereby preventing a thin film on the semiconductor substrate from being damaged. It is in.

[Means for solving the problem]

The plasma etching apparatus of the present invention is provided with a filament in which thermoelectrons are generated inside a reaction chamber and a target for generating secondary electrons by the thermoelectrons.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a plasma etching apparatus for explaining one embodiment of the present invention.

In FIG. 1, the plasma etching apparatus has a gas inlet tube 1 and a gas outlet tube 2, and has electrodes 4, 6 inside a reaction chamber 3.
Are disposed opposite to each other and include a gas supply source connected to the gas introduction pipe 1, a high vacuum source connected to the gas discharge pipe 2, and a high-frequency oscillator 7 connected to the electrodes 4 and 6. Is a plasma etching apparatus in which a semiconductor substrate 5 having undergone a photoresist process is placed on an etching treatment table also serving as an electrode 6, and an etching gas is introduced from a gas introduction pipe 1 to selectively remove and process a pattern. A filament 8 for generating thermoelectrons and a target 9 for receiving the thermoelectrons and generating secondary electrons are arranged near the interior of the chamber 3.

According to the present embodiment configured as described above, the filament 8 that generates thermoelectrons and the target 9 that receives the thermoelectrons and generate secondary electrons are arranged inside the reaction chamber 3, so that immediately before the end of etching. The function of causing a current to flow through the filament 8 to generate thermoelectrons is activated, and the semiconductor substrate 5
By pouring the secondary electrons down, the accumulation of charged particles that occurs when the high frequency is cut off can be prevented in the form of neutralization.
Damage to the underlying thin film can be eliminated.

In the above embodiment, a single-wafer plasma etching apparatus has been described. However, it goes without saying that the same effect can be obtained with a batch-type plasma etching apparatus that simultaneously processes a plurality of wafers.

〔The invention's effect〕

As described above, the present invention has an effect of preventing damage to a thin film of a semiconductor device by providing a filament and a target for generating secondary electrons in a reaction chamber.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the present invention. 1 ... gas introduction pipe, 2 ... gas discharge pipe, 3 ... reaction chamber,
4,6 ... electrodes, 5 ... semiconductor substrate, 7 ... high frequency power supply,
8 ... filament, 9 ... target.

Claims (1)

(57) [Claims] (1) maintaining a vacuum in the reaction chamber by a vacuum pump;
In a plasma etching apparatus that applies a high-frequency voltage to an electrode disposed in the reaction chamber and excites or ionizes the introduced gas to etch a semiconductor substrate held on the electrode, a thermoelectron is introduced into the reaction chamber. A plasma etching apparatus comprising: a filament to be generated; and a target to generate secondary electrons by the thermal electrons.