JPS59124725A - Plasma etching apparatus - Google Patents

Abstract

PURPOSE:To prevent deterioration of yield and quality due to defective pattern formation and pin holes, etc. by providing a plate for shielding a high frequency power between upper electrode plate and semiconductor substrate. CONSTITUTION:A porous plate 7 having countless number of holes 8 which shield a high frequency power is placed in parallel to the electrode 4 between the upper electrode 4 among the electrodes 4, 5 which are provided in parallel in both sides of semiconductor substrate 6 placed on the etching board 5 within the reaction tube 3 and said semiconductor substrate 6. Thereby, the high frequency power shielding plate 7 weakens a high frequency power applied on the semiconductor substrate 6 and the etching to the part which becomes a protection film can be suspended.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plasma etching apparatus used for manufacturing semiconductor devices.

Conventionally, plasma etching equipment, which selectively patterns a metal film or insulating film attached to the surface of a semiconductor substrate using an oxide film or a photoresist film as a protective film, has been used with an electrode connected to a high-frequency oscillator located at the center of the reaction tube. The etching process was installed perpendicularly to the semiconductor substrate mounted on the etching table in the section, but the etching uniformity within the semiconductor substrate was poor (the etching was faster at the periphery).
In addition, there were drawbacks such as slow etching speed and no increase in processing capacity, so in order to make etching uniform within the semiconductor substrate and improve processing capacity, the electrode position was narrowed and parallel to the top of the semiconductor substrate. placed at the bottom.

However, although this made the etching rate uniform within the semiconductor substrate, the electric field acting between the upper and lower electrodes was too strong, and the etching rate was lower than that of the conventional method (the electrodes could not be placed perpendicularly to the outside of the semiconductor substrate). The oxide film or photoresist film that should be a protective film on the semiconductor substrate is etched, and the metal film or insulating film that is covered by the protective film and should remain is etched. This causes defective pattern formation, pinholes, etc., leading to a decrease in yield and quality of semiconductor devices.

SUMMARY OF THE INVENTION An object of the present invention is to provide an effective plasma etching apparatus that eliminates the drawbacks of the conventional apparatus.

The plasma etching apparatus of the present invention includes, for example, a cylindrical reaction tube having a gas inlet tube and a gas outlet tube, with electrodes arranged inside the reaction tube, a gas supply source connected to the gas inlet tube, and a gas outlet tube connected to the gas outlet tube. A semiconductor substrate that has undergone a photoresist process is placed on an etching table that includes a connected high vacuum source and a high frequency oscillator connected to the electrode, and is installed in the center of the reaction tube, and selectively etches patterns using various etching gases. In a plasma etching system, a large number of holes are placed between the semiconductor substrate and the upper electrode of electrodes placed in parallel to sandwich the semiconductor substrate placed on an etching table installed inside a reaction tube to cut off high-frequency power. It has a structure in which a plate with holes is installed parallel to the electrode.

The plasma etching apparatus of the present invention has a plate that cuts off high frequency power between the upper electrode plate and the semiconductor substrate, which weakens the electrolytic force that hits the semiconductor substrate, slows down the etching speed, and removes the portion that should serve as a protective film. I was able to prevent it from being etched.

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

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

The plasma etching apparatus of this embodiment has a gas introduction tube 1 and a gas discharge tube 2, a cylindrical reaction tube 3 with electrodes 4 and 5 arranged inside the reaction tube 3, and a gas connected to the gas introduction tube 1. an etching table 5 (having the function of an electrode) installed at the center of the reaction tube 3, including a supply source, a cylindrical vacuum source connected to the gas exhaust pipe 2, and a high frequency oscillator connected to the electrodes 4 and 5;
This is a plasma etching apparatus in which a semiconductor substrate 6 that has undergone a photoresist process is placed on a substrate, and a moderate amount of etching gas is introduced from a gas introduction tube 1 to selectively etch a pattern. A plate 7 with numerous holes 8 for cutting off high frequency power is placed between the upper electrode 4 and the semiconductor substrate 6 of the electrodes 4 and 5 which are placed parallel to each other with the semiconductor substrate 6 sandwiched between them. It is installed in

That is, according to this embodiment, the high-frequency power cutoff plate 7 installed between the electrode 4 and the semiconductor substrate 6 can weaken the high-frequency power impinging on the semiconductor substrate 6, thereby preventing etching of the portion that should become a sleep-retaining film. It is possible to prevent pattern formation defects, pinholes, etc. in the portions covered by the protective film that should remain as patterns, and as a result, it can contribute to improving the yield and quality of semiconductor devices. Furthermore, even if a high-frequency power cutoff plate 7 is provided between the electrode 4 and the semiconductor substrate 6, the plasma etching device is 1.5 The etching speed is ~1.7 times faster, which also leads to improved processing capacity.

In the above embodiments, a plasma etching apparatus that processes a single semiconductor substrate is used, but it can also be applied to a plasma etching apparatus that can process multiple semiconductor substrates at once. It goes without saying that similar effects can be obtained even if a high frequency power cutoff plate is applied between the semiconductor substrate and the electrodes in a plasma etching apparatus in which the electrodes are arranged vertically.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a plasma etching apparatus for explaining an embodiment. In the figure, 1... gas introduction pipe, 2...
...Gas exhaust pipe, 3...Reaction tube, 4...
... Electrode, 5 ... Etching table (having the function of electrode), 6 ... Semiconductor substrate, 7 ...
...High frequency power cutoff plate, 8...holes. 6-

Claims (1)

[Claims] A cylindrical reaction tube having a gas introduction pipe and a gas exhaust pipe and an electrode arranged inside the reaction tube, a gas supply source connected to the gas introduction pipe, a high vacuum source connected to the gas exhaust pipe, and connected to the electrode. In a plasma etching apparatus including a high frequency oscillator, a semiconductor substrate placed on an etching table inside the reaction tube is narrowed and a plurality of holes are formed between the upper electrode of electrodes placed in parallel and the semiconductor substrate. A plasma etching apparatus characterized in that a metal plate is installed parallel to the upper electrode.