JPH0621004A - Plasma etching device - Google Patents

Abstract

PURPOSE:To equalize etching by installing a substrate in the vicinity of the resonance point of electronic cyclotron resonance point, and besides, applying FR bias of 40KHz. CONSTITUTION:The high-speed anisotropic etching of an Al metallic film or an Si substrate can be materialized uniformly with single Cl2 gas even on the level of 10<-4>Torr by applying 40KHzRF bias to the substrate installed on an electronic cyclotron resonance point 5. Furthermore, in the etching of Al alloy, it can be etched on the level of 10<-4>Torr, so it also has the effect of post corrosion being hard to occur on the sidewall of a pattern, since the adsorption of Cl2 onto the sidewall is little. Hereby, the high-speed etching on the level of 10<-4>Torr is possible, and complete anisotropic etching can be materialized even with single Cl2 gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to etching of a substrate surface by using plasma generated by using electron cyclotron resonance phenomenon, particularly Al alloy wiring and Si on a semiconductor substrate.
Regarding substrate etching.

[0002]

2. Description of the Related Art Conventionally, as an apparatus of this type, Japanese Patent Laid-Open No.
There is an invention described in Japanese Patent Publication No. 155535. The microwave plasma processing technology shown here is that the microwave is generated from a microwave generator via a waveguide and a microwave introduction window in a plasma generation chamber where a magnetic field of a predetermined strength is applied using a coil. Introduces an electron cyclotron resonance phenomenon, and the energy generated by this makes the gas in the plasma generation chamber introduced from the gas introduction system into plasma, and the plasma flows from the extraction window with plasma by utilizing the divergent magnetic field created by the magnetic field. The substrate is pulled out into the substrate processing and the substrate placed on the substrate holder is etched by the ion bombardment.

[0003]

However, in the above-mentioned conventional technique, the ion current density reaching the substrate is extremely small, and therefore the etching rate is low even when the RF bias is applied. Therefore, the pressure during etching is set to 10
-It must be etched at a high pressure of ³ Torr or more,
Therefore, a side wall protective film is required, and a gas containing C is required. Further, since the RF bias of 13.56 MHz is applied, the etching becomes non-uniform, and the variation in the shape within the wafer is large.

[0004]

Unlike the conventional electron cyclotron resonance etching described above, the present invention is 10 ^−4.
In order to provide a high ion current density and ion directionality on the Torr stand, there is a difference in that the substrate is placed near the electron cyclotron resonance point and etching is performed by applying an RF bias of 400 KHz.

[0005]

The present invention is characterized in that a substrate is installed near an electron cyclotron resonance point and an RF bias of 400 KHz is applied.

As a result, high-speed etching can be performed on the order of 10 ^-4 Torr, and complete anisotropic etching can be realized even with Cl ₂ gas alone.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a sectional view of an apparatus to which the present invention is applied. A single gas of Cl ₂ was introduced into this apparatus and 5 × 10 ⁻⁴
Al-S in case of introducing microwave 1 kW at Torr
An example of etching characteristics of the i-Cu (0.5%) film and the Si substrate is shown.

FIG. 2 shows 400 at Cl ₂ : 50 sccm.
The etching rate distribution when a kHz RF bias of 50 W and 100 W is applied is shown. Even under a low pressure of 5 × 10 ^-4 Torr, high-speed etching of 5000 A / min or more is uniformly realized. At this time, the etching shape achieves anisotropic etching, and a selection ratio of 2 to 3 can be obtained with respect to the resist.

FIG. 3 shows that when Cl ₂ : 50 sccm, 40
The etching rate distribution when a 0 kHz RF bias of 200 W is applied is shown. High-speed anisotropic etching of 5000 A / min or more is uniformly realized.

[0011]

As described above, according to the present invention, by applying the 400 kHz RF bias to the substrate installed at the electron cyclotron resonance point, even in the 10 ^-4 Torr range,
High-speed anisotropic etching of an Al metal film or a Si substrate can be uniformly realized by using only Cl ₂ gas.

Further, in Al alloy etching,
Since etching can be performed on the order of 10 ⁻⁴ Torr, there is an effect that Cl is less adsorbed on the pattern side wall and post corrosion is less likely to occur.

[Brief description of drawings]

FIG. 1 is a sectional view of an apparatus to which the present invention is applied.

FIG. 2 is a graph showing etching of an Al—Si—Cu alloy film using the apparatus of the present invention.

FIG. 3 is a graph showing etching of a Si substrate using the apparatus of the present invention.

Claims (1)

[Claims] 1. A process gas is made into plasma by utilizing an electron cyclotron resonance phenomenon caused by an electric field generated by microwaves in a plasma generation chamber and a magnetic field orthogonal to the electric field, and the plasma is irradiated onto a substrate on which the processing gas is installed. In a microwave plasma processing apparatus for processing a substrate, Cu,
When etching an Al alloy film containing Ti, Si, etc. or a silicon substrate, place the substrate in the vicinity of the electron cyclotron resonance point, apply a high frequency bias of 400 KHz to the substrate, and perform high-speed etching using chlorine gas alone. An ECR plasma etching apparatus characterized by: