JP2915341B2 - Electrostatic chuck device - Google Patents

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 dry etching apparatus, and more particularly to an electrostatic chuck apparatus for electrostatically adhering a wafer and other objects to be processed.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of a semiconductor device, after depositing various films on a semiconductor substrate such as silicon, oxygen gas,
There is known a technique of dry-etching the film using neutral plasma radicals by using gas plasma such as CF ₄ gas. In this type of dry etching apparatus, an object to be processed is usually mounted on a mounting table in a vacuum atmosphere, and the temperature of the object to be processed is controlled by heat transfer from the mounting table. In this case, in order to reliably control the temperature up to the outermost peripheral portion of the object to be processed and to prevent the back surface of the outer peripheral portion of the object from being etched, the size of the metal electrode of the electrostatic chuck device is required. However, it is necessary to set the size to be equal to or larger than the size of the object to be processed.

[0003]

By setting the size of the metal electrode to be larger than that of the object to be processed, the temperature can be reliably controlled over the entire outer peripheral edge of the object to be processed. There is a problem that the surface of the protective film outside the region to be processed is partially damaged by the etching action. In other words, while applying a DC voltage to the electrode plate of the electrostatic chuck device and holding the object to be suction-fixed with the electrostatic chuck electrode, the reaction gas is supplied into the vacuum vessel,
When dry etching is performed, the protective film of the mounting table that protrudes outside from the object to be processed is sputtered and the film is reduced, and the underlying polymer organic film is etched by a gas containing oxygen or a halogen element. However, there has been a problem that the metal is exposed and the attraction force is significantly reduced.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to prevent an electrostatic chucking force from deteriorating even on a mounting table larger than the external dimensions of a workpiece. Is to provide.

[0005] In order to achieve the above object, the present invention provides a dry etching apparatus in which an object to be processed is electrostatically adsorbed by covering the outside of a metal electrode with an insulating film and applying a DC voltage. In the electrostatic chuck device, a protective film is provided on an upper surface of the insulating film, and the metal electrode has a plurality of electrode pieces formed in a circular shape as a whole, and an annular ring disposed outside the electrode pieces. A voltage close to the ground potential is applied or no voltage is applied to the ring-shaped electrode piece, and the outer diameter of the plurality of electrode pieces formed in a circle as a whole is The outer diameter of the annular electrode piece is set to be larger than the outer diameter of the workpiece, and is smaller than the outer diameter of the workpiece .
The inner diameter of the electrode piece is set smaller than the outer diameter of the workpiece.
It is characterized by having.

[0006] Even if the electrostatic chuck according to the present invention is used for a long time in a chemical dry etching apparatus, the protective film made of fluororesin is not reduced by DC discharge, and the outermost peripheral portion of the object to be processed is also used in the electrostatic chuck apparatus. The temperature control can be effectively performed because of the contact, and the etching of the back surface of the outer peripheral portion of the object can be prevented, so that the device can be used for a long time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electrostatic chuck device according to the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a chemical dry etching apparatus according to the present invention, in which an etching chamber 2 is formed inside a vacuum vessel 1,
A mounting table 3 is hermetically fixed to the bottom of the vacuum vessel 1. A cooling passage 4 constituting a part of a temperature control mechanism is formed inside the mounting table 3, and cooling water or the like whose temperature has been adjusted is introduced or discharged through a water supply pipe 5 and a drain pipe 6.

An electrostatic chuck device 7 is mounted on the mounting table 3.
Is fixed, and the object to be processed A is attracted and held on the upper surface of the electrostatic chuck device 7 using electrostatic force. The electrostatic chuck device 7 includes an electrode plate 8 composed of a plurality of electrode pieces.
2 and 3, the electrode plate 8 is composed of a pair of semicircular electrode pieces 8A and 8B and an annular electrode piece 8C arranged outside thereof. ing. The electrode piece 8A is connected to a positive DC power supply 9, and the electrode piece 8B is connected to a negative DC power supply 10. No voltage is applied to the electrode piece 8C.

The size of the object to be processed A is a pair of electrode pieces 8A.
And 8B, and smaller than the diameter of the electrode piece 8C. The electrode plate 8 is entirely covered with an insulating film 11 of a polymer organic material such as a polyimide resin film, and is adhered to the upper surface of the mounting table 3 via an adhesive. A protective film 12 made of fluororesin is adhered to the upper surface of the insulating film 11 using an adhesive.

On the other hand, a gas dispersion plate 13 is installed above the etching chamber 2 so as to face the mounting table 3, and a gas introduction pipe 14 is connected to the gas dispersion plate 13, and a plasma generator (shown in FIG. CF ₄ + O activated by omission)
_Two gases are introduced into the etching chamber 2. In FIG. 1,
Reference numeral 15 denotes an exhaust pipe, and 16 denotes a pressure gauge for detecting the pressure in the etching chamber 2.

In FIG. 1, reference numeral 17 denotes a gas introduction pipe, and the upper end of the gas introduction pipe 17 is provided on the mounting table 3 and the insulating film 1.
1. A gas, such as helium, is supplied through the center of the electrode plate 8 and the protective film 12, and is opened on the lower surface of the object A to be processed and the boundary between the object A and the protective film 12. Gas introduction piping 1
In the middle of 7, a pressure gauge 18 constituting a part of the gas supply mechanism is provided.
And a gas flow control valve 19, and a variable valve 21 is provided on a discharge pipe 20 of the gas introduction pipe 17 which branches off from the gas flow control valve 19.

Next, the operation of the dry etching apparatus according to the present invention configured as described above will be described. In FIG. 1, first, the object to be processed A is placed on the upper surface of the protective film 12 made of the fluororesin of the electrostatic chuck device 7 on the mounting table 3, and the inside of the etching chamber 2 is evacuated to a vacuum through the exhaust pipe 15.
A voltage is applied from the DC power supply 9 to the electrode plates 8A and 8B of the electrostatic chuck electrode 7, and the object A is electrostatically fixed on the mounting table 3.

Next, the CF ₄ + O ₂ gas activated by a plasma generator (not shown) is introduced into the etching chamber 2 from the introduction pipe 14 through the gas dispersion plate 13 to etch the workpiece A. Do. At this time, the inside of the etching chamber 2 is controlled to a predetermined pressure based on the instruction of the pressure gauge 16.
Cooling water of a predetermined temperature is supplied to the cooling passage 4 of the mounting table 3 to adjust the temperature of the mounting table 3.

In the meantime, when a voltage is applied by a DC power supply and the object A is electrostatically fixed on the mounting table 3, even if gas is introduced into the etching chamber 2, the electrode pieces 8 A and 8 B
Is smaller than the diameter of the processing object A, the DC discharge does not occur in the etching chamber 2 due to the gas pressure, so that the protective film 12 made of fluororesin does not decrease, so that the insulating film 11 is not eroded by etching for a long time. Dry etching can be performed over a wide range. In the above embodiment, the electrode pieces 8A and 8B are formed in a semicircular shape. However, the present invention is not limited to this. The electrode pieces may be divided into quadrants, and the number of divisions is not limited.

[0015]

As is clear from the above description, according to the present invention, the metal electrode plate of the electrostatic chuck device is made smaller than the object to be processed, and the metal on the concentric circle immediately below the outermost peripheral portion of the object to be processed. Since the electrode made is larger than the object to be processed and a voltage close to the ground potential is applied, or no charge is applied,
Since the back surface of the object is not etched and has a cooling effect, it can be used for a long time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a dry etching apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view showing the structure of an electrostatic chuck electrode.

FIG. 3 is a plan view showing an arrangement state of electrode pieces.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Etching chamber 3 Mounting table 7 Electrostatic chuck electrode 8 Electrode piece 11 Insulating film 12 Protective film

Claims (3)

(57) [Claims] 1. An electrostatic chuck device for a dry etching apparatus, wherein an outside of a metal electrode is covered with an insulating film and a DC voltage is applied to electrostatically attract an object to be processed. A protective film is provided on the upper surface, and the metal electrode is composed of a plurality of electrode pieces formed in a circular shape as a whole and an annular electrode piece arranged outside the electrode piece. To the piece, a voltage close to the ground potential is applied or no voltage is applied, and the outer diameter of the plurality of electrode pieces formed as a whole in a circle is smaller than the outer diameter of the workpiece, On the other hand, the outer diameter of the annular electrode piece is set to be larger than the outer diameter of the workpiece .
Further, the inner diameter of the ring-shaped electrode piece is
An electrostatic chuck device for a dry etching device, wherein the electrostatic chuck device is set smaller than an outer diameter . 2. The electrostatic chuck device according to claim 1, wherein the plurality of electrode pieces formed in a circle as a whole are a pair of semicircular electrode pieces. 3. The electrostatic chuck device according to claim 1, wherein all the electrode pieces have the same thickness.