JPS62241336A - Plasma etching device - Google Patents

Abstract

PURPOSE:To obtain a plasma etching device in which etching speeds between wafers are uniformized, by uniformizing a flow of gas inside an etching chamber. CONSTITUTION:A plasma etching device is provided with a hexagon pole electrode 3 centrally inside the etching chamber 1, and gas-introduction tubes 6 for introducing an etching gas are installed on the side plane of the etching chamber, and besides two exhaustion ports 5, 5 are formed at the bottom part of the etching chamber, in a symmetrical position in which the hexagon pole electrode 3 is centered. Since the two exhaustion ports 5 are symmetrically positioned around the hexagon pole electrode 3, a flow of a gas, which flows along the periphery of the hexagon pole electrode 3 and from gas-ejection nozzles 8 to the exhaustion ports 5, is uniformized, and the gases supplied to the wafer surfaces become identical in their amounts even if the wafers 7 are set anywhere on the hexagon pole electrode 3. Hence, etching speeds are prevented from being scattered due to differences in the amounts of supplying the etching gases, precision in the etching processes can be improved to obtain high-yield and high-quality etching processes of fine patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plasma etching apparatus used for manufacturing semiconductor devices.

[Conventional technology]

Conventionally, in plasma etching equipment that selectively etches patterns on 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, the semiconductor substrate (hereinafter referred to as a wafer) is etched in a central corner of the etching chamber. It is fixedly installed on each side of the columnar electrode,
The etching gas is blown out from a gas jet nozzle attached to the side surface of the etching chamber, and the gas flows toward the exhaust port at the bottom of the etching chamber.

The conventional plasma etching apparatus described above usually has one gas exhaust port.

[Problem that the invention seeks to solve]

As a result, the gas atmosphere inside the etching chamber becomes non-uniform, and the wafers installed at the positions where the wafers are installed, for example, the wafers installed facing the gas exhaust port and the wafers installed on the opposite side of the gas exhaust port, In this case, there will be a difference in the gas supply amount, which will cause variations in the etching speed, etc.
As a result, pattern processing accuracy varies within a wafer and between wafers, resulting in a decrease in yield quality.

Furthermore, as wafers become larger and semiconductor devices become denser and smaller, this problem has come into focus.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma etching apparatus in which the etching rate among wafers is made uniform by making the flow of gas in the etching chamber uniform.

[Means for solving problems]

The plasma etching apparatus of the present invention has a prismatic electrode for placing a semiconductor substrate in the center of the etching chamber, and a gas jet nozzle on the side of the etching chamber, which are arranged symmetrically with respect to the prismatic electrode at the bottom of the etching chamber. It is characterized by having a plurality of exhaust ports.

〔Example〕

Next, one embodiment of 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.

Conventionally, a plasma etching apparatus used for manufacturing semiconductor devices has a hexagonal prism TLTW 43 connected to a high frequency oscillator 2 in an etching chamber 1, a pump 4 connected to an exhaust port 5 in the etching chamber 1, and an etching gas introduced into the etching chamber 1. It has a structure having a gas introduction pipe 6 and a hexagonal column electrode 3.
After setting the wafer 7 in the etching chamber 1, the inside of the etching chamber 1 is kept in a vacuum by the vacuum pump 4, the etching gas is introduced into the etching chamber 1 through the gas introduction pipe 6, and when the pressure in the etching chamber is stabilized, the high frequency oscillator 2 is used to remove the octagonal. A high frequency voltage is applied to the pillar electrode 3, and the surface of the wafer 7 is etched.

Since there is only one gas exhaust port, the gas flow is only in one direction from the gas jet nozzle 8 to the gas exhaust port 5. Since the amount of etching gas that hits the surface of the wafer 7 differs between different wafers, there is a difference in etching speed, resulting in variations in processing accuracy.

Therefore, the plasma etching apparatus of the present invention is equipped with an octagonal prism electrode 3 at the center of the etching chamber 1, a gas introduction pipe 6 for introducing etching gas into the side of the etching chamber, and an octagonal prism electrode 3 at the bottom of the etching chamber. Two exhaust ports 5, 5 are provided at symmetrical positions about the center.

That is, according to the present invention, there are two
Since the exhaust ports 5 are located in symmetrical positions, the flow of gas from the gas jet nozzle 8 to the exhaust port 5 along the periphery of the octagonal column electrode 3 is uniform, and the wafer 7 can be set anywhere on the octagonal column electrode 3. However, the amount of gas supplied to the wafer surface is the same, eliminating variations in etching speed due to differences in the amount of etching gas supplied, improving etching accuracy, and etching fine patterns with high yield and high quality. It will be done.

In the above embodiment, the central electrode is a hexagonal prism and the number of exhaust ports is two. However, depending on the size of the device and the size of the wafer, the shape of the electrode may be a square prism or an octagonal prism, or the shape of the exhaust port may be changed to The number may be three or more.

〔Effect of the invention〕

The plasma etching apparatus of the present invention has a plurality of exhaust ports arranged symmetrically around a prismatic electrode located at the center of the etching chamber, so that the etching gas emitted from the gas jet nozzle installed on the side of the etching chamber The gas flows uniformly around the prismatic electrode, eliminating differences in gas supply amount due to differences in the wafer placement position, making it possible to equalize the etching speed between wafers and improving pattern processing accuracy. It has the effect that it can.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a plasma etching apparatus for explaining one embodiment of the present invention. 1... Etching chamber 52... High frequency oscillator, 3...
・Octagonal prism electrode, 4...Pump, 5...Exhaust port, 6.
...Gas introduction pipe, 7...-Wafer, 8...Gas jet nozzle patent applicant Kyushu NEC Co., Ltd. -1+-41... Agent: Patent attorney Naka Kanno 1. ．． Note 1) l: Nonie - 1st life -

Claims (1)

[Claims] (1) The etching chamber has a prismatic electrode on which the semiconductor substrate is placed in the center, a gas ejection nozzle on the side of the etching chamber, and multiple exhaust gas outlets at symmetrical positions around the prismatic electrode at the bottom of the etching chamber. A plasma etching device characterized by having an opening.