JP2001223259A - Electrostatic attracting electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic attracting device which can prevent the breakage of an insulator dielectric layer and abnormal discharge. SOLUTION: This electrostatic attracting device is provided with an insulator dielectric layer 27 having an attracting surface 27a whereon an object 1 to be treated, a pair of electrostatic electrodes 29A and 29B to generate a leak current for attracting the object 1, a high-frequency impressing electrode 31 to apply a high-frequency voltage to the object 1, and a heater 33 to heat the object 1. The electrostatic electrodes 29A and 29B, high-frequency impressing electrode 31 and the heater 33 are integrally formed within the insulator dielectric layer 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck electrode for applying a high-frequency voltage while holding a substrate to be processed by electrostatic force in a plasma processing apparatus such as a dry etching apparatus.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional electrostatic attraction electrode of this kind. The electrostatic attraction electrode includes a ceramic insulating dielectric layer 3 having an attraction surface 3a on which the substrate 1 is placed, and a metal plate 5 made of a metal having good thermal conductivity such as aluminum. I have. The insulating dielectric layer 3 and the metal plate 5 are fixed to each other by bolts 7.

A pair of electrostatic electrodes 9A and 9B are built in the insulator dielectric layer 3. These electrostatic electrodes 9
A and 9B are DC power supplies 11A and 11B and high-frequency power supply 1
3 and is connected to. On the other hand, a heater 15 is built in the metal plate 5. This metal plate 5
Is connected to an AC power supply 17.

When a voltage is applied from the DC power supplies 11A and 11B to the electrostatic electrodes 9A and 9B, a minute leakage current flows through the insulating dielectric layer 3, so that an electrostatic force (Johnson-Rahbek force) is applied to the substrate 1 to be processed. ) Acts and is adsorbed and held on the adsorption surface 3a. The electrostatic electrodes 9A and 9B have
The high frequency power for generating plasma is a high frequency power supply 13
Is applied. Further, the heat generated by the heater 15 supplied with power from the AC power supply 17 causes
Is heated, and the insulating dielectric layer 3 and the substrate 1 to be processed are heated by the heat conduction from the metal plate 5.

[0005]

However, the conventional electrostatic chucking electrode has the following problems.

First, since the thermal expansion difference between the insulating dielectric layer 3 and the metal plate 5 is large, stress concentration occurs near the bolt 7 during heating by the heater 15, and as a result, the insulating dielectric layer 3 may be damaged. is there. Further, during the plasma processing, the electric charges concentrate on the bolt 7, and there is a possibility that abnormal discharge occurs. Furthermore, since high-frequency power for generating plasma is applied to the electrostatic electrodes 9A and 9B, the state of the plasma is affected by the shapes of the electrostatic electrodes 9A and 9B, and uniform etching cannot be performed.

Accordingly, an object of the present invention is to provide an electrostatic chucking electrode capable of preventing breakage of an insulating dielectric layer and abnormal discharge. Another object of the present invention is to provide an electrostatic chucking electrode capable of improving the uniformity of the plasma processing.

[0008]

According to a first aspect of the present invention, there is provided an electrostatic attraction electrode for electrostatically attracting and holding an object to be processed and for applying a high frequency voltage. An insulating dielectric layer having an attraction surface on which the object is placed, and a pair of electrostatic electrodes for generating a leakage current for adsorbing the object formed in the insulating dielectric layer A high-frequency application electrode for applying a high-frequency voltage to the object to be processed formed in the insulator dielectric layer, and a heater for heating the object to be processed formed in the insulator dielectric layer It is intended to provide an electrostatic attraction electrode comprising:
Since the electrostatic chuck electrode of the present invention has an integral structure in which the electrostatic electrode, the high-frequency application electrode, and the heater are formed in the insulator dielectric layer, the insulator dielectric layer is damaged due to stress concentration caused by a difference in thermal expansion. Can be prevented. Further, since the above-described integrated structure does not require a bolt, it is possible to prevent occurrence of abnormal discharge during plasma processing.
Furthermore, since the high-frequency application electrode is provided separately from the electrostatic electrode, the state of the plasma is not affected by the shape of the electrostatic electrode,
Plasma treatment with excellent uniformity can be performed.

It is preferable that at least a part of the outer edge of the high-frequency applying electrode is located outside the outer edge of the electrostatic electrode when viewed from the suction surface side. It is preferable that the entire outer edge of the application electrode is located outside the outer edge of the electrostatic electrode. If the outer edge of the high-frequency application electrode is located outside the outer edge of the electrostatic electrode, the plasma state, particularly near the outer edge of the workpiece, is not affected by the shape of the electrostatic electrode, and plasma processing with excellent uniformity is performed. It can be carried out.

[0010] The insulating dielectric layer is formed at a temperature of 100 ° C to 500 ° C.
It is preferably made of ceramics having a volume resistivity of 10 ⁸ to 10 ¹³ Ω · cm in the range of ° C. If the volume resistivity of the ceramics constituting the insulating dielectric layer is set within the above range, an appropriate leakage current flows through the insulating dielectric layer,
The sufficient electrostatic force ensures that the object to be processed is adsorbed and held on the suction surface of the insulating dielectric layer, while excessive leakage current may destroy the device on the object mounted on the insulating dielectric layer. Can be prevented.

It is preferable that the electrostatic electrode and the high frequency applying electrode are made of conductive ceramics or conductive metal.

According to a second aspect of the present invention, there is provided a chamber accommodating at least an electrode for applying a high-frequency voltage to a workpiece,
A plasma processing apparatus comprising: a vacuum exhaust unit that evacuates the chamber and a gas supply source that supplies a gas into the chamber, wherein the electrode has an adsorption surface on which the object is placed. An insulating dielectric layer, a pair of electrostatic electrodes for generating a leakage current for attracting the object to be processed formed in the insulating dielectric layer, and the insulating layer formed in the insulating dielectric layer; An object of the present invention is to provide a plasma processing apparatus including a high-frequency application electrode for applying a high-frequency voltage to a processing object and a heater for heating the processing object formed in the insulating dielectric layer.

According to a third aspect of the present invention, there is provided a method of electrostatically adhering an object to be processed to a high-frequency voltage applying electrode for applying a high-frequency voltage to the object in a plasma processing apparatus. A pair of electrostatic electrodes, the high frequency application electrode, and a heater are provided in the body dielectric layer, a DC voltage is applied to the electrostatic electrodes, and the object to be processed is electrostatically charged by a leakage current flowing between the electrostatic electrodes. An object of the present invention is to provide an electrostatic attraction method in which the object is attracted by force, a high frequency voltage is applied to the object by the high frequency applying electrode, and the object is heated by the heater.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention shown in the drawings will be described in detail. FIG. 1 shows an RIE which is a plasma processing apparatus including an electrostatic chucking electrode 20 according to an embodiment of the present invention.
1 shows a (reactive ion etching) apparatus.

At the bottom of the chamber 21 of the RIE apparatus, an electrostatic chucking electrode 20 as a cathode is provided. The chamber 21 is grounded, and its inner wall forms an anode. Further, a vacuum pump (vacuum evacuation means) 23 and a gas supply source 25 are connected to the chamber 21. Furthermore, the chamber 21 is provided with an opening / closing mechanism (not shown) for moving the substrate 1 to be processed into and out of the chamber.
An organic thin film and a resist pattern (not shown) are previously formed on the substrate 1 by a process such as resist and exposure.

The electrostatic chucking electrode 20 shown in FIG.
10 in the range of 100 ° C to 500 ° C ⁸From 10¹³Ωcm
Insulator Dielectric Layer with Specific Volume Resistance
27. In the figure of the insulator dielectric layer 27,
The upper surface constitutes a suction surface 27a on which the substrate 1 is placed.
ing. In addition, the insulating surface 2
A pair of electrostatic electrodes in order from the 7a side (upper side in the figure)
29A and 29B, the high-frequency application electrode 31 and the heater 33
They are arranged in layers. In the present embodiment, the electrostatic electrode 2
9A, 29B, high frequency application electrode 31, heater 33
The displacement is also made of conductive ceramics. Thus, the real
The electrostatic attraction electrode 20 of the embodiment is made of a conductive ceramic.
The electrostatic electrodes 29A and 29B, the high-frequency
Cover 33 with an insulating dielectric layer 27 made of ceramics.
Ceramic three-layer structure.

As shown in FIG. 3A, each of the pair of electrostatic electrodes 29A and 29B has a semi-disc shape, and includes a plurality of comb-like portions 29a provided at predetermined intervals. These electrostatic electrodes 29A and 29B are
a are inserted into each other such that they do not contact each other. The electrostatic electrodes 29A and 29B are connected to a DC power supply 37 for electrostatic attraction by conductive wires 35A and 35B, respectively.
A, 37B.

As shown in FIG. 3B, the high-frequency applying electrode 31 has a disk shape. In addition, the high-frequency application electrode 31 is connected to the DC electrodes 37A,
A pair of through holes 31a and 31b for inserting conductive lines 35A and 35B connected to 7B are provided. The high-frequency applying electrode 31 is connected to a high-frequency power supply 41 via a matching circuit (not shown) by a conductive line 39.

The heater 33 is connected to an AC power supply 43 for supplying electric power for heating.

As shown in FIG. 4, when the insulating dielectric layer 27 is viewed from the suction surface 27a side (upper side in the figure), the entire outer edge 31c of the high-frequency application electrode 31 is formed by the electrostatic electrodes 29A and 29A.
9B is located outside the outer edge 29b. In the present embodiment, the distance t from the outer edge 31c of the high frequency applying electrode 31 to the outer edge 29b of the electrostatic electrodes 29A and 29B is 2.5 cm.
(About 1 inch).

Next, the RI provided with the electrostatic chucking electrode 20
The operation of the E device will be described. First, the electrostatic attraction electrode 2
The substrate 1 to be processed is placed on the suction surface 27a of the “0”. Next, the DC electrodes 37A, 37B supply the electrostatic electrodes 29A, 29A.
DC voltage is applied to B. Thereby, the electrostatic electrode 29
A minute leakage current flows through the insulating dielectric layer 27 between A and 29B, and the substrate 1 to be processed is adsorbed and held on the adsorption surface 27a by an electrostatic force (Johnson-Rahbek force) due to the leakage current. Thereafter, the inside of the chamber 21 is
The pressure is reduced to a predetermined degree of vacuum, and the reaction gas is supplied from the gas supply source 25.

Next, an AC voltage is applied to the heater 33 from the AC power supply 43, and the heater 33 generates heat. The heat generated by the heater 33 is transferred via the insulating dielectric layer 27 to heat the substrate 1 on the adsorption surface 27a. In one embodiment of the present embodiment, the power supply to the heater 33 is adjusted so that the temperature of the substrate 1 to be processed becomes 220 ° C. and the temperature of the insulating dielectric layer 27 becomes 250 ° C. When a high-frequency voltage is applied from the high-frequency power supply 41 to the high-frequency application electrode 31, plasma 45 is generated in the chamber 21, and the organic thin film on the substrate 1 to be processed is etched according to the pattern of the resist.

Since the electrostatic attraction electrode 20 has an integral structure including the electrostatic electrodes 29A and 29B, the high-frequency application electrode 31, and the heater 33 in the insulating dielectric layer 27 as described above, heat generated by the heater 33 is generated. Even if the temperature of the insulating dielectric layer 27 rises due to the above, stress concentration due to a difference in thermal expansion does not occur, and damage to the insulating dielectric layer 27 can be prevented.

The electrostatic attraction electrode 20 has an integral structure including the electrostatic electrodes 29A and 29B, the high-frequency application electrode 31, and the heater 33 in the insulating dielectric layer 27 as described above.
It does not include the bolt 7 (see FIG. 5) unlike the conventional electrostatic attraction electrode. Therefore, abnormal discharge due to the presence of the bolt can be prevented.

Further, a high frequency application electrode 31 for applying a high frequency voltage is provided separately from the electrostatic electrodes 29A and 29B for electrostatic attraction as described above, and an outer edge 31c of the high frequency application electrode 31 is provided. Are located outside the outer edges 29b of the electrostatic electrodes 29A and 29B, the plasma state especially near the outer edge of the substrate 31 to be processed is
Etching with excellent uniformity can be performed without being affected by the shape of 20B.

Further, as described above, the insulating dielectric layer 2
Since the ceramics constituting 7 has a volume resistivity of 10 ⁸ to 10 ¹³ Ω · cm in the range of 100 ° C. to 500 ° C., an appropriate leakage current flows through the insulating dielectric layer 27, and sufficient electrostatic force is applied. The substrate 1 to be processed surely has the suction surface 27a.
The device formed on the substrate 1 to be processed is not broken by excessive leakage current.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, the above-mentioned electrostatic electrode, high frequency application electrode and electrostatic electrode may be made of a conductive metal such as tungsten. Further, the shapes of the high-frequency application electrode and the electrostatic electrode are not limited to a circle, but may be, for example, a rectangular shape.

When viewed from the suction surface 27a side of the insulator guiding layer 27, the entire outer edge 31c of the high-frequency applying electrode 31 does not necessarily need to be located outside the outer edges 29b of the electrostatic electrodes 29A and 29B. The outer edge 3 of the high frequency applying electrode 31
At least a part of 1c needs to be located outside the outer edge 29b of the electrostatic electrodes 29A and 29B. Electrostatic electrodes 29A and 29B of outer edge 31c of high-frequency applying electrode 31
The longer the portion located outside of the outer edge 29b, the more stable the plasma and the more uniform the etching process.

The electrostatic attraction electrode of the present invention is not limited to the above-mentioned RIE apparatus, but may be an electron cyclotron resonance (ECR) plasma etching, an inductively coupled plasma (ICP) etching, a helicon wave plasma etching, a cylindrical plasma etching, or a plasma separation type. The present invention can also be applied to other dry etching apparatuses using various types of plasma including microwave plasma etching, and plasma processing apparatuses such as plasma CVD apparatuses.

[0030]

As is clear from the above description, the electrostatic attraction electrode has an integral structure in which the electrostatic electrode, the high-frequency application electrode, and the heater are formed in the insulating dielectric layer, and thus is caused by the difference in thermal expansion. It is possible to prevent the dielectric dielectric layer from being damaged and the occurrence of abnormal discharge due to the stress concentration. In addition, since the high-frequency application electrode is provided separately from the electrostatic electrode, plasma processing excellent in uniformity without being affected by the shape of the electrostatic electrode can be performed.

[Brief description of the drawings]

FIG. 1 shows an R having an electrostatic attraction electrode according to an embodiment of the present invention.
It is a schematic diagram showing an IE device.

FIG. 2 is a schematic sectional view showing an electrostatic chucking electrode according to the embodiment of the present invention.

FIG. 3A is a perspective view showing a high-frequency application electrode,
(B) is a perspective view showing an electrostatic electrode.

FIG. 4 is a plan view for explaining a dimensional relationship between a high-frequency application electrode and an electrostatic electrode.

FIG. 5 is a schematic sectional view showing a conventional electrostatic attraction electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate to be processed 20 Electrostatic adsorption electrode 21 Chamber 23 Vacuum pump 25 Gas supply source 27 Insulator dielectric layer 27a Adsorption surface 29A, 29B Electrostatic electrode 29a Comb-like part 29b Outer edge 31 High frequency application electrode 31a, 31b Through hole 31c Outer edge 33 Heater 35A, 35B, 39 Conductive wire 37A, 37B DC power supply 41 High frequency power supply 43 AC power supply 45 Plasma

Claims (7)

[Claims] 1. An insulating dielectric layer for electrostatically attracting and holding an object to be processed and applying a high-frequency voltage, said insulating dielectric layer having an attraction surface on which the object to be processed is mounted. A pair of electrostatic electrodes for generating a leakage current for adsorbing the object to be processed formed in the insulating dielectric layer; and a high frequency wave applied to the object to be processed formed in the insulating dielectric layer. An electrostatic chucking electrode comprising: a high-frequency application electrode for applying a voltage; and a heater for heating the object formed in the insulating dielectric layer. 2. The electrostatic device according to claim 1, wherein at least a part of the outer edge of the high-frequency applying electrode is located outside the outer edge of the electrostatic electrode when viewed from the suction surface side. Adsorption electrode. 3. The method according to claim 2, wherein the insulating dielectric layer is formed at a temperature of 100.degree.
3. The electrostatic chucking electrode according to claim 1, which is made of ceramics having a volume resistivity of 10 ⁸ to 10 ¹³ Ω · cm in a range of 0 ° C. 4. The electrostatic attraction electrode according to claim 1, wherein the electrostatic electrode and the high-frequency application electrode are made of conductive ceramics. 5. The electrostatic attraction electrode according to claim 1, wherein the electrostatic electrode and the high frequency application electrode are made of a conductive metal. 6. A chamber accommodating at least an electrode for applying a high-frequency voltage to an object to be processed, vacuum evacuation means for evacuating the chamber, and a gas supply source for supplying gas into the chamber. A plasma processing apparatus comprising: an electrode, an insulating dielectric layer having an adsorption surface on which the object is placed, and a leakage current for adsorbing the object formed in the insulating dielectric layer. A pair of electrostatic electrodes for generating the same, a high-frequency application electrode for applying a high-frequency voltage to the object to be processed formed in the insulating dielectric layer, and a high-frequency application electrode formed in the insulating dielectric layer. A plasma processing apparatus comprising: a heater for heating the object to be processed. 7. A method for electrostatically adhering an object to be processed to a high-frequency application electrode for applying an object to a high-frequency voltage in a plasma processing apparatus, the method comprising: A pair of electrostatic electrodes, the high-frequency applying electrode, and a heater are provided, a DC voltage is applied to the electrostatic electrodes, and the object to be processed is attracted by electrostatic force by a leakage current flowing between the electrostatic electrodes. An electrostatic suction method in which a high-frequency voltage is applied to the object by the high-frequency applying electrode, and the object is heated by the heater.