JPH03129821A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the loading effect especially generating when the density of a pattern greatly varies locally by a method wherein an etching treatment is conducted by introducing etching gas between a wafer-placed electrode and an auxiliary electrode, and deposition gas is introduced between the auxiliary electrode and the opposing electrode. CONSTITUTION:An auxiliary electrode 103 is provided between parallelplaced electrodes 101 and 102, gas introducing holes 104 and 105 are provided between the lower electrode 101 and the auxiliary electrode 103 and also between the upper electrode 102 and the auxiliary electrode 103 respectively. SF6 is introduced into a gas introducing hole 104, and CC14 is introduced into a gas introducing hole 104 respectively, and an etching treatment is conducted alternately by generating plasma. In this case, when plasma is generated between the upper electrode and the auxiliary electrode 103, a plasma etching mode (PE mode) is employed, and when plasma is generated between the lower electrode 101 and the auxiliary electrode 103, a reaction ion etching mode (RIE mode) is employed. By conducting the etching treatment using the above-mentioned PE mode and RIE mode alternately, loading effect is eliminated, and the resultant configurational difference can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to etching.

[Conventional technology]

Conventionally, etching apparatuses provided with such auxiliary electrodes have been used for the purpose of increasing the probability of electron collision and increasing the etching rate.

For this reason, the gas was also introduced without distinguishing between the upper and lower parts of the auxiliary electrode, and a high frequency was applied.For example, when polycrystalline silicon was etched under the conditions shown in Table 1, the etching rate was 42
00 people/min, which is 40% higher than that without auxiliary electrodes. However, in such etching, a loading effect in which the etching speed varies depending on the density of the pattern cannot be avoided, and the shape also varies depending on the density, as shown in FIG.

Table 1 [Problems and Objectives to be Solved by the Invention] Conventional techniques had the problem of a large loading effect and a tapered shape where the pattern was sparse.

The present invention provides a method for solving such problems.

[Means to solve the problem]

The method for manufacturing a semiconductor device of the present invention uses a dry etching apparatus in which an auxiliary electrode is provided between electrodes placed in parallel, and a high frequency is applied to generate plasma to perform etching. The etching process is characterized in that etching is performed by introducing an etching gas between the auxiliary electrode and the electrode facing the wafer.

[Effect]

The present invention has a feature that the loading effect is reduced by performing deposition and etching alternately, but this is because the etching speed increases where the etching area is large, whereas
This is because, conversely, where the etching area is small, the etching speed is low, whereas the deposition speed is also low, so they cancel each other out.

〔Example〕

The present invention will now be described in detail based on examples.

FIG. 1 shows the etching apparatus used in the present invention, in which an auxiliary electrode (103) is provided between electrodes (101, 102) placed in parallel, and a gas inlet (104,
105) are provided between the lower electrode and the auxiliary electrode and between the upper electrode and the auxiliary electrode, respectively.

When etching polycrystalline silicon using this etching apparatus, SF6 is introduced into the gas inlet (104) and CCl4 is introduced into the gas inlet (105), and plasma is generated alternately to perform etching. When plasma is generated between the lower electrode and the auxiliary electrode, the plasma etching mode (hereinafter referred to as PE mode) is used, and when the plasma is generated between the lower electrode and the auxiliary electrode, the reactive ion etching mode (hereinafter referred to as RIE mode) is used. (called mode)
becomes. This allows the deposition gas such as CCl4 to be
Plasma is generated in E mode to deposit a deposit, and etching is performed by generating plasma in RIE mode using an etching gas such as SF6. The reason why etching is performed in RIE mode at this time is to perform anisotropic etching, and if the deposition gas and etching gas are introduced in reverse, good etching will not be performed.

Table 2 The conditions under which etching was performed in this example are as shown in Table 2, and deposition was performed alternately at a cycle of 2.5 seconds and etching at a cycle of 1 second.

When performed in this way, conventionally the etching rate was high in areas where the etching area was large, but since the deposition rate is high in areas where the area is large, deposition and etching are performed alternately so that they cancel each other out. The etching process can be done in the same manner regardless of the size of the area. Also, the shape is vertical, as shown in FIG. 2, regardless of the size of the etched area.

Although CCl4 has been described as the deposition gas, the deposition gas is not limited to this, and similar effects can be obtained with CH2F2, CH3F, and the like.

On the other hand, the etching gas is not limited to SF6, but may also be NF3 or the like.

By performing etching using a triode type etching apparatus and alternately using PE mode and RIE mode as in this embodiment, the loading effect is eliminated, and the resulting difference in shape is also eliminated.

〔Effect of the invention〕

The present invention has the effect of being able to reduce the loading effect that occurs particularly when the pattern is highly dense and dense.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an etching apparatus used in this example. FIG. 2 is an etched cross-sectional view when etching was performed in this embodiment. FIG. 3 is a cross-sectional view of etching when etching is performed using the conventional technique. 101... Lower electrode 102... Upper electrode 103... Auxiliary electrode 104... Gas inlet port 1 105... Gas inlet port 2 106... Wafer 107... Exhaust port 201°202°203゜204゜108...High frequency power supply 301...Resist 302...Polycrystalline silicon 303...Silicon oxide film 304...Silicon substrate or more

Claims (1)

[Claims] In dry etching equipment, an auxiliary electrode is provided between electrodes placed in parallel and etching is performed by applying high frequency waves to generate plasma. A method for manufacturing a semiconductor device, characterized in that etching is performed by introducing a deposition gas between electrodes facing each other.