JPH07106300A - Electrostatic chuck equipment - Google Patents

Abstract

PURPOSE:To prevent etching of an insulative polymer organic film. CONSTITUTION:A mounting stand 2 is arranged in a vacuum chamber of a plasma isolation type chemical dry etching equipment, and consists of an aluminum plate 11 and an electrostatic chuck 12 fixed on the aluminum plate 11. The electrostatic chuck 12 consists of an electrode 13 made of a metal thin film, an insulative polymer organic film 14 surrounding the whole part of the electrode 13, and fluororesin 19 covering the exposed part of the polymer organic film 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck apparatus for a plasma processing apparatus, and more particularly to an electrostatic chuck apparatus suitable for a plasma separation type chemical dry etching apparatus.

[0002]

2. Description of the Related Art Various dry etching apparatuses are used for manufacturing LSIs and other various semiconductor elements. FIG. 2 shows a general structure of a plasma-separated chemical dry etching apparatus. A reaction table 1 is provided with a mounting table 2, and a processing object 3 such as a wafer is mounted on the mounting table 2. ing. A gas dispersion plate 4 is arranged above the reaction chamber 1, and the gas dispersion plate 4 has a plurality of openings 4a, and these openings 4a face the object 3 to be processed. The gas dispersion plate 4 is connected to a plasma generation chamber 6 by a gas introduction pipe 5, and the plasma generation chamber 6 is composed of a quartz discharge tube 7 and a waveguide 8 arranged outside the discharge tube 7. Has been done. One end of the discharge tube 7 is connected to the gas introduction tube 5, and a gas containing CF ₄ , O _2, etc. is introduced from the other end. When the waveguide 8 applies microwaves to the discharge tube 7, plasma is generated in the discharge tube 7. An exhaust pipe 9 is connected to the bottom of the vacuum chamber 1, and the exhaust pipe 9 is connected to a vacuum pump (not shown) to exhaust the reactive gas from the vacuum chamber 1. A power supply 10 is connected between the mounting table 2 and the outer wall of the vacuum chamber 1.

The mounting table 2, as shown in detail in FIG.
It is composed of an aluminum plate 11 and an electrostatic chuck 12 mounted on the aluminum plate 11. The aluminum plate 11 has a flow path 11a through which a constant temperature fluid flows.
The constant temperature fluid keeps the mounting table 2 at a constant temperature. The electrostatic chuck 12 includes an electrode 13 made of a metal thin film.
And an insulative polymer organic film 14 that surrounds the entire electrode 13, and attracts and holds the workpiece 3 by electrostatic force. The electrons and ions generated in the discharge tube 7 are attenuated in the gas introduction tube 5 on the way, hardly reach the vacuum chamber 1, and the influence on the object to be processed 3 can be substantially ignored. Therefore, the object 3 is etched by the neutral active radicals.

[0004]

However, in the conventional plasma-separated type chemical dry etching apparatus, the polymer organic film 14 of the electrostatic chuck 12 is gradually etched during the etching of the object 3 to be processed, Finally, there was a problem that the metal thin film electrode 13 was exposed and the electrostatic attraction force was significantly reduced.

The fact that the polymer organic film is subjected to etching will be described in detail with reference to experimental examples. The experiment was conducted as follows. First, a wafer that has been subjected to the following processing is prepared as the object to be processed 3. That is, as shown in FIG. 4, a thermal oxide film 16 having a thickness of about 1000 Å is formed on the surface of the silicon substrate 15 by a thermal oxidation method, and a thickness of about 8000 is formed on the surface of the thermal oxide film 16 by a sputtering method.
An Angstrom aluminum alloy layer 17 is deposited. A film thickness of 1800 is formed on the aluminum alloy layer 17.
Masking is performed with a positive resist 18 having a thickness of about 0 angstrom. This is placed in a parallel plate type plasma etching apparatus, the aluminum alloy layer 17 is etched, and the object 3 to be processed in FIG. 4 is created.

The object to be treated 3 of FIG. 4 thus prepared is placed on the placing table 2 of FIG. 2 and CF ₄ = 100 scc
m, O ₂ = 1000 sccm, microwave power = 700
Under the conditions of W and the pressure in the vacuum chamber = 30 Pa, the positive resist 18 of the workpiece 3 was ashed, that is, ashed. In this ashing process, it was found that the ashing rate of the positive resist 18 was 1 μm / min, and the etching rate on the side surface of the polymer organic film 14 reached 0.05 μm / min. Thus, the polymer organic film 1
No. ₄ is strongly etched by the ashing treatment using CF ₄ and O ₂ gas by the plasma etching apparatus, so that the metal thin film electrode 13 is exposed by the conventional plasma separation type chemical dry etching apparatus for a relatively short period of time. Resulting in. Therefore, the purpose of the present invention is to
An object of the present invention is to provide an electrostatic chuck device that prevents etching of an insulating polymer organic film.

[0007]

In order to achieve this object, the invention described in claim 1 is arranged in a plasma processing apparatus for converting a gas containing at least fluorine into plasma to process an object to be processed, In an electrostatic chuck device for electrostatically attracting the object to be processed, a metal electrode, an insulating polymer organic film surrounding the entire metal electrode, and an exposed surface of the polymer organic film are provided. And a fluororesin coating.

According to a second aspect of the present invention, the above-mentioned reaction of the plasma-separated chemical dry etching apparatus is provided with a plasma-generating chamber for converting a gas containing at least fluorine into plasma and a reaction chamber separated from the plasma-generating chamber. In an electrostatic chuck device that electrostatically adsorbs an object to be processed in a room, a metal electrode, an insulating polymer organic film surrounding the entire metal electrode, and an exposed surface of the polymer organic film And a fluororesin for coating.

[0009]

The fluororesin is not etched by neutral radicals even if it is etched by ions. Therefore, even if the electrostatic chuck device is used in the plasma processing device for a long time, the polymer organic film is always covered with the fluorine resin and is not exposed.
It will not be etched.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electrostatic chuck device according to the present invention will be described below with reference to FIG. 1 in which the same parts as those in FIGS. In FIG. 1, the mounting table 2 is
The aluminum plate 11 and an electrostatic chuck 12 mounted on the aluminum plate 11 are provided. The aluminum plate 11 is provided with a flow path 11a through which a constant temperature fluid flows. The table 2 is kept at a constant temperature. The electrostatic chuck 12 includes an electrode 13 made of a metal thin film,
Insulating polymer organic film 14 surrounding the entire electrode 13
And a fluororesin 19 covering the exposed portion of the polymer organic film 14. Since the fluorine resin 19 is thus coated on the upper surface and all side surfaces of the polymer organic film 14, the polymer organic film 14 is not exposed at any part.

The mounting table 2 having such a configuration is arranged in the reaction chamber 1 of the plasma separation type chemical dry etching apparatus shown in FIG. The fluorine resin 19 is etched by ion sputtering, however,
It is not etched by neutral radicals.
As described above, in the plasma separation type chemical dry etching apparatus shown in FIG. 2, electrons and ions generated in the discharge tube 7 are attenuated in the gas introduction tube 5 on the way and do not substantially flow into the vacuum chamber 1. Therefore, the fluorine resin 19 is not substantially subjected to the etching action, and therefore the polymer organic film 14 is always covered with the fluorine resin 19. When the same experiment as the above-mentioned experiment was conducted on the electrostatic chuck 12 having such a configuration, the ashing rate of the positive resist 18 of the object to be processed 3 shown in FIG.
At m / min, the polymer organic film 14 was not etched at all.

[0012]

As is apparent from the above description, according to the present invention, since the fluorine resin is not etched by the neutral radicals, even if the electrostatic chuck device is used for a long time in the plasma processing device, The polymer organic film is always covered with a fluororesin, is not exposed, and is not subjected to etching. Therefore, the life of the electrostatic chuck device can be significantly extended.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an electrostatic chuck device according to the present invention.

FIG. 2 is a schematic view showing a conventional plasma separation type chemical dry etching apparatus.

FIG. 3 is a sectional view showing the mounting table of FIG. 2 in detail.

FIG. 4 is a cross-sectional view showing an example of an object to be processed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber (vacuum chamber) 3 Object to be treated 6 Plasma generation chamber 12 Electrostatic chuck 13 Metal electrode 14 Polymer organic film 19 Fluorine resin

Claims (2)

[Claims] 1. A plasma processing apparatus for processing an object by converting a gas containing at least fluorine into plasma,
In an electrostatic chuck device for electrostatically attracting the object to be processed, a metal electrode, an insulating polymer organic film surrounding the entire metal electrode, and an exposed surface of the polymer organic film are provided. An electrostatic chuck device comprising: a fluororesin coating. 2. An object to be treated is electrostatically charged in the reaction chamber of a plasma-separated chemical dry etching apparatus having a plasma generation chamber for converting a gas containing at least fluorine into plasma and a reaction chamber separated from the plasma generation chamber. In the electrostatic chuck device for electrostatically adsorbing, a metal electrode, an insulating polymer organic film surrounding the entire metal electrode, and a fluororesin covering the exposed surface of the polymer organic film are provided. An electrostatic chuck device characterized in that