JPH06196548A - Electrostatic chuck - Google Patents

Abstract

(57) [Summary] [Purpose] By impregnating the pores of the sprayed ceramic film with resin, the withstand voltage is increased and the sample holding power is high.
Also, to provide an electrostatic chuck capable of reliably holding a sample. [Structure] The mounting table 1 is composed of a metal disk electrode 2 and a sealing insulating film 3 in which pores of an insulating film formed by spraying a ceramic material are impregnated with resin. The terminal 4 is provided on the side. The mounting table 1 has a lower half of the mounting table 1 fitted into the recess of a water cooling jacket 6 having a recess at the center of the surface thereof. An insulating cylinder 5 having a flange 5a at its lower end is fitted in a hole formed in the center of the recess of the water cooling jacket 6, and the terminal 4 is fitted to this insulating cylinder 5 from the flange 5a to approximately half the screw 4a. Is inserted so as to project. For the insulating cylinder 5 and the water cooling jacket 6, a nut 7 is screwed onto the threaded portion 4a of the terminal 4 and the mounting table 1 is tightened.
The mounting table 1 which is in close contact with the water cooling jacket 6 is arranged in the water cooling jacket 6 and is cooled by the flow of the refrigerant into the flow holes 6a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck for holding a sample by electrostatic action in a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art In a thin film forming process or a dry etching process in a semiconductor manufacturing process, a sample is surely placed on a mounting table on which a sample is mounted in order to perform required film formation or etching on a flat sample such as a wafer. Need to be in close contact. As a sample holding device that meets such requirements, an electrostatic chuck that uses an electrostatic action to bring a sample into close contact with and hold it on a mounting table is widely used.

FIG. 3 is a schematic cross-sectional view showing a conventional electrostatic chuck, in which 1 is a mounting table on which a sample is mounted. The mounting table 1 includes a metal disk electrode 2 and an insulating film 13 whose surface is coated with a ceramic material to a thickness of 100 μm to 500 μm by a thermal spraying method.
It consists of and. A cylindrical terminal 4 is provided on the rear surface side of the center of the mounting table 1, and the terminal 4 has a screw portion 4a at the lower end thereof. The terminal 4 is connected to a DC power source (not shown) to induce an electrostatic force.

The mounting table 1 has a lower half of the mounting table 1 fitted in the recess of a water cooling jacket 6 having a recess at the center of the surface thereof. An insulating cylinder 5 having a flange portion 5a at its lower end is fitted in a hole formed in the center of the recess of the water cooling jacket 6, and the terminal 4 has approximately half the flange portion 5a to the screw portion 4a. It is inserted protruding. That is, the water cooling jacket 6 and the terminal 4 are insulated by the insulating cylinder 5.
The insulating cylinder 5 and the water cooling jacket 6 are designed so that the nut 7 is screwed into the threaded portion 4a of the terminal 4, and the tightening of the nut 7 causes the mounting table 1 to come into close contact with the mounting table 1. It is designed to be cooled by the flow of the refrigerant into the flow hole 6a arranged in the water cooling jacket 6.

In order to hold the sample with the electrostatic chuck constructed as described above, the sample is placed on the mounting table 1 (not shown) and a positive (negative) voltage is applied to the terminal 4. The surface of the metal disk electrode 2 is charged with a positive (negative) charge, and the back surface of the sample is charged with a negative (positive) charge through the insulating film 13, and the sample is adsorbed on the mounting table 1 by the electrostatic action of the positive and negative charges. Hold it.

[0006]

[Problems to be Solved by the Invention]
Conventional electrostatic chucks use alumina (Al₂O
₃) Ceramic powder is sprayed by plasma
Since it is configured by covering the insulating film by the method,
It can be manufactured with no process, and it has high heat resistance and durability.
There is an advantage. However, the insulating film coated in this way
Has a high porous shape with many small pores
Since the insulation film has a low withstand voltage,
The power is low. Also, through this pore, the sample and the metal disk electrode
There is a risk that discharge may occur between
It was The present invention has been made in view of such circumstances.
The purpose of this is to cover the pores of the sprayed insulation film.
Impregnation with oil increases the withstand voltage and holds the sample
An electrostatic chuck that has high force and can hold the sample securely
To provide.

[0007]

In an electrostatic chuck according to the present invention, an insulating film formed by spraying a ceramic material onto an electric conductor is coated on the electric conductor, and the object to be attracted and the electric conductor are covered. An electrostatic chuck configured to apply a direct current voltage between and to adsorb the object to be adsorbed, comprising the conductor in which pores of the insulating film generated by the thermal spray are impregnated with resin. Is characterized by.

[0008]

Since the electrostatic chuck of the present invention comprises the conductor in which the pores present in the insulating film formed by spraying the ceramic material are impregnated with the resin, the dielectric strength of the insulating film is the dielectric breakdown of the resin. The strength is close to the strength, and the high voltage can be applied to enhance the adsorption holding power of the adsorbent, and since the pores of the insulating film are sealed, the discharge between the adsorbent and the conductor can be increased. There is no possibility that the sample will not be retained due to the occurrence of

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. FIG. 1 is a schematic sectional view showing an electrostatic chuck of the present invention, in which 1 is a mounting table. The mounting table 1 is composed of a metal disk electrode 2 and a sealing insulating film 3 obtained by impregnating pores of an insulating film having a ceramic material sprayed thereon with a resin. A cylindrical terminal 4 is provided on the rear surface side of the center of the mounting table 1, and a lower end screw portion 4a of the terminal 4 is connected to a DC power source (not shown) to induce an electrostatic force.

The mounting table 1 has a lower half of the mounting table 1 fitted into the recess of a water cooling jacket 6 having a recess at the center of the surface thereof. An insulating cylinder 5 having a flange portion 5a at its lower end is fitted in a hole formed in the center of the recess of the water cooling jacket 6, and the terminal 4 has approximately half the flange portion 5a to the screw portion 4a. It is inserted protruding. That is, the water cooling jacket 6 and the terminal 4 are insulated by the insulating cylinder 5.
The insulating cylinder 5 and the water cooling jacket 6 are designed so that the nut 7 is screwed into the threaded portion 4a of the terminal 4, and the tightening of the nut 7 causes the mounting table 1 to come into close contact with the mounting table 1. It is designed to be cooled by the flow of the refrigerant into the flow hole 6a arranged in the water cooling jacket 6.

In order to hold the sample with the electrostatic chuck constructed as described above, a sample (not shown) is placed on the mounting table 1 and a positive (negative) voltage is applied to the terminal 4. The surface of the metal disk electrode 2 is charged with positive (negative) charges, and the back surface of the sample is charged with negative (positive) charges through the insulating film 3, and the sample is adsorbed on the mounting table 1 by the electrostatic action of the positive and negative charges. Hold. At this time, since the sealing insulating film 3 covering the metal disk electrode 2 is formed by impregnating the pores generated in the insulating film sprayed with the ceramic material with the resin as described above, the characteristics of the ceramic material are The holding voltage of the sample is further improved by having it, and the holding power of the sample is improved, and since there is no pore in the sealing insulating film 3, there is no fear of discharge between the sample and the metal disk electrode 2.

Next, the results of comparison of the withstand voltage of the device of the present invention and the conventional device will be described. FIG. 2 is a schematic diagram showing a state in which the withstand voltage is measured, and 21 in the figure is a grounded metal container. The metal container 21 contains water, and the electrostatic chuck 10 connected to the terminal 22a of the ammeter 22 is immersed in the water with the mounting table 1 facing down. And the terminal of the ammeter 22
Silicon resin is applied from the connecting portion of the electrostatic chuck 10 to the upper portion of the water of the terminal 22a. The other end of the ammeter 22 is connected to one end of a DC power supply 24 in parallel with the voltmeter 23, and the other end of the DC power supply 24 is connected to the side wall of the metal container 21. Then, from the DC power supply 24, the electrostatic chuck 10 and the metal container
Gradually raise the voltage applied between the
Voltmeter with the voltage when 0.5 mA is measured as the withstand voltage
Read from 23.

Table 1 shows the results. Conventional example those in which the thickness thereof 300 [mu] m by spraying the Al ₂ O ₃ on the surface of the aluminum electrode, the inventive examples Al ₂ O ₃
After thermal spraying, the resin is impregnated into the pores generated in the Al ₂ O ₃ film by heating to the melting point of the resin under reduced pressure to seal the pores.
After that, 10 units each of which was dried were used. Since the resin is impregnated into the pores in a depressurized state in this way, the gas in the pores is removed and the resin spreads throughout the pores, and the molten resin is degassed to generate bubbles. do not do. Incidentally, in the present invention example 1, an epoxy resin was used as the resin, and in the present invention example 2, a silicone resin was used. The dielectric breakdown strength of these resins is 2 to 10 kV / 0.1 mm.

[0014]

[Table 1]

As can be seen from Table 1, the withstand voltage was less than 100 V in all the tests in the conventional example, while it is 500 to 1,000 in the case of sealing with the epoxy resin in the example of the present invention.
V and 700 to 2,000 V when sealed with a silicone resin, and the withstand voltage of the present invention is 5 to 20 times higher than that of the conventional example. Although epoxy resin and silicone resin are used as the resin in this embodiment, it is needless to say that the resin is not limited to this and may be a resin having required dielectric breakdown strength and heat resistance.

[0016]

As described above in detail, in the electrostatic chuck of the present invention, the holding power of the sample can be improved, so that the plasma processing can be accurately performed on the sample and the product yield can be improved. The present invention has excellent effects such as improved reliability and increased reliability of the device for reliably holding the sample.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an electrostatic chuck of the present invention.

FIG. 2 is a schematic diagram showing a state in which a withstand voltage is measured.

FIG. 3 is a schematic cross-sectional view showing a conventional electrostatic chuck.

[Explanation of symbols]

 1 Mounting table 2 Metal disk electrode 3 Sealing insulation film 4 Terminal 5 Insulation cylinder 6 Water cooling jacket 7 Nut

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H02N 13/00 D 8525-5H

Claims (1)

[Claims] 1. An insulating film formed by spraying a ceramic material onto an electric conductor is coated on the electric conductor, and a DC voltage is applied between the object to be adsorbed and the object to be adsorbed. In the electrostatic chuck made as described above, the electrostatic chuck is provided with the conductor in which pores of the insulating film generated by the thermal spraying are impregnated with a resin.