JPH04127426A - Plasma etching apparatus - Google Patents

Abstract

PURPOSE:To obtain a plasma etching apparatus which can make the distribution of a plasma uniform and which can execute a uniform etching operation because microwaves can be radiated uniformly to a treatment chamber by a method wherein a coaxial waveguide and a cylindrical resonator are used to supply the microwaves. CONSTITUTION:Microwaves oscillated from a microwave oscillator are guided by using a rectangular waveguide 1 and enter a coaxial waveguide 2. The electric-field direction of the microwaves inside the coaxial waveguide 2 is set to a radius direction. The microwaves enter a cylindrical resonator 3 and are resonated. The electric-field direction inside the cylindrical resonator 3 is also set to a radius direction. As a result, the coupling degree of the waveguide 2 to the resonator 3 is high and the microwaves are not reflected here. Since the waveguide 2 is connected to the center of the resonator 3, the intensity distribution of the microwaves inside the resonator 3 does not become imbalanced. Consequently, the microwaves are radiated uniformly into a treatment chamber 6 from a slot antenna 4. Thereby, the maintained density distribution of a plasma becomes uniform, and a wafer is etched uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plasma etching apparatus for semiconductor L8I manufacturing equipment, and more particularly to a plasma etching apparatus advantageous for uniformly processing wafers.

[Conventional technology]

As semiconductor L8I becomes highly integrated, patterns are becoming finer. Along with this, a highly accurate processing technique is required in the etching process for forming a pattern on the substrate. The conditions necessary for high-precision processing are, of course, that it can be processed directly according to the mask dimensions, that is, there is no need for side etching under the mask, and that it has good selectivity with the underlying film. , to perform these processes at high speed and uniformly. For this purpose, lowering the processing pressure is effective, and a plasma processing method using microwaves is suitable.

Regarding the processing method using microwaves, JP-A No. 6
It is shown in the l-10s088 publication.

(Problems to be Solved by the Invention) The above-mentioned conventional device does not take into consideration the point of uniformly radiating microwaves to the processing area, and the intensity of the radiated microwaves is biased depending on the connection position of the waveguide. There was a problem.The result.

The density distribution of the generated plasma also becomes non-uniform.

An object of the present invention is to uniformly radiate microwaves to a geographic room, and to provide a microwave mode converter for this purpose.

[Means to solve the problem]

In order to achieve the above objective, it is first necessary to uniformly introduce microwaves into the cylindrical resonator.

Also, in order to improve the coupling when introducing the microphone 0 wave,
It is necessary to align the electric field direction of the incident microwave in the same direction as the electric field direction inside the cylindrical resonator.

For this purpose, the rectangular waveguide used to guide microwaves from the microwave oscillator is not connected directly to the resonator, but is connected to a coaxial waveguide at -degrees. death,
The structure is such that the coaxial waveguide is connected to a cylindrical resonator.

[Effect]

The direction of the electric field within the cylindrical resonator is radial, as shown in FIG. Therefore, in order to introduce microwaves into this resonator, it is necessary that the electric field direction of the incident microwaves also be in this direction. In the conventional system, the direction of the electric field within the rectangular waveguide was as shown in FIG. 5, so this connection was configured as shown in FIG. 4 to match the direction of the electric field. Therefore, the intensity distribution of the microwaves within the resonator becomes biased, and as a result, the intensity distribution of the microwaves supplied to the processing chamber also becomes biased.

In the present invention, by connecting a rectangular waveguide to a coaxial waveguide, the direction of the electric field can be aligned in the direction shown in FIG. By connecting the two, it is possible to match the direction of the electric field. Furthermore, since the microwave is supplied from the center of the resonator, the intensity distribution of the microwave within the resonator is not biased.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. Referring to FIG. 1, microwaves oscillated from a microwave oscillator (not shown) are guided by a rectangular waveguide 1, and then enter a coaxial waveguide 2. The direction of the microwave electric field within the coaxial waveguide 2 is the radial direction, as shown in FIG.

The microwave further enters the cylindrical resonator 3 and resonates. Since the direction of the electric field in Iζ in the circular tram resonator 5 is also radial, the degree of coupling between the waveguide [2 and the resonance a5 is high, and the microwave is not reflected here.

Furthermore, since the waveguide 2 is connected to the center of the resonator 5, no bias occurs in the microwave intensity distribution within the resonator 5. Therefore, the microwave has a slot anti-f
4 to the processing chamber 6.

The processing chamber 6 and the microwave transmission window 5 constitute a vacuum chamber, which is evacuated through an exhaust pipe 10 by a vacuum pump (not shown). Further, a processing gas whose flow rate is controlled by an R amount controller (not shown) is introduced into the processing chamber 6 through a gas introduction port 7, and the inside of the processing chamber is maintained at a predetermined vacuum atmosphere.

The processing gas is turned into plasma by the microwave radiated from the slot antenna 4, and the wafer set on the mounting table is etched.

Since the intensity distribution of the microwaves radiated from the slot antenna 4 is uniform, the density distribution of the maintained plasma is also uniform, and the wafer is etched uniformly.

〔Effect of the invention〕

According to the present invention, since microwaves can be uniformly radiated into the processing chamber, the plasma distribution can be made uniform and uniform etching can be performed.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the direction of the electric field within the cylindrical resonator, FIG. 5 is an explanatory diagram showing the direction of the electric field within the rectangular waveguide, and FIG. The figure is an explanatory diagram showing the electric field direction when a rectangular waveguide and a cylindrical resonator are combined, and Figure 5 is an explanatory diagram showing the electric field direction when a coaxial waveguide and a cylindrical resonator are combined. It is a diagram. DESCRIPTION OF SYMBOLS 1... Rectangular waveguide, 2... Coaxial waveguide, G... Cylindrical resonator, 4... Slot antenna, 5... Microwave transmission window, 6... Processing chamber, 7... Gas introduction pipe, 8
...Wafer! ...TJ% on wafer, 10...
Exhaust pipe. Figure, l last χ 3; Complementary type common muscle (No.

Claims (1)

[Claims] 1. A vacuum container, means for supplying etching gas into the vacuum container, means for supplying microwaves into the vacuum container to generate plasma, and holding a wafer in the vacuum container. What is claimed is: 1. A plasma etching apparatus comprising a wafer-mounted electrode, characterized in that a coaxial waveguide and a cylindrical thermal resonator are used to supply the microwave. 2. The plasma etching apparatus according to claim 1, wherein the cylindrical resonator has an electric field direction that coincides with a radial direction. 3. The plasma etching apparatus according to claim 1, wherein the coaxial waveguide is connected to the center of the cylindrical resonator.