JP2001338970A - Electrostatically attracting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatically attracting apparatus superior in plasma transparency by facilitating manufacture in simple and easy structure, enhancing manufacturing yield to make a manufacturing cost inexpensive, improving the heat conductance of an electrostatically attracted plate-like specimen and a temperature control part, and facilitating maintaining of the temperature of the plate-like specimen at a desirable constant temperature. SOLUTION: The electrostatically attracting apparatus 1 is provided with an insulation dielectric layer 4 mounting the plate-like specimen, an electrode layer 5 formed on the rear face of the insulation dielectric layer 4, an insulating body layer 6 comprising polyimide-based resin coating the electrode layer 5, and a temperature control part 3 adhered to and joined on the insulating body layer 6. The withstand voltage of the polyimide-based resin is 50 KV/mm or more, permittivity 4 or less, dielectric loss tangent 0.01 or less, the thickness of the insulating body layer 20-50 μm, the thickness of the electrode layer 0.01-200 μm, the thickness of the dielectric layer 0.5-4 mm, and the insulating body layer and the temperature control part are joined and adhered by an adhesive having rubber elasticity.

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 fixing a plate-like sample by electrostatic force.

[0002]

2. Description of the Related Art Basically, an electrostatic attraction device comprises an insulating dielectric layer for mounting and supporting a plate-like sample, and a conductor layer for generating an electrostatic force for fixing the plate-like sample. Consists of
When processing a plate-like sample by incorporating it into a plasma processing apparatus, the temperature of the plate-like sample is an important factor contributing to the reaction in the processing process. Temperature is controlled so as to keep the temperature at a desired constant temperature. Thus, the mechanism for controlling the temperature of the plate-like sample of the electrostatic adsorption device increases the thermal conductivity by forcibly bringing the plate-like sample into close contact with and fixing to the sample supporting portion by electrostatic force, thereby increasing water or helium ( He) Temperature control is performed by introducing a refrigerant such as gas into the temperature control structure on the back surface of the sample support.

[0003] Therefore, as an example of a conventional electrostatic attraction device, first, as a first example, an insulating dielectric plate on which a plate-like sample is placed and an insulating dielectric plate supporting the insulating dielectric plate. The electrostatic chuck unit including the conductive support plate and the electrode layer sandwiched between the insulating dielectric plate and the support plate is bonded to the temperature control unit with or without the thermal expansion moderating layer. -A bonded electrostatic attraction device is exemplified. As a second example, an electrode layer is formed on the back surface of an insulating dielectric plate on which a plate-shaped sample is placed by printing or the like, and this dielectric plate is bonded to an insulating support plate using an organic adhesive. There is known an electrostatic chuck device in which an electrostatic chuck portion is formed, and the electrostatic chuck portion is bonded and joined to a temperature control portion with or without a thermal expansion alleviating layer.

[0004]

However, in the electrostatic chuck of the first example, the manufacturing process is complicated due to its complicated structure, the manufacturing yield is low and the manufacturing cost is increased. Is present, the thermal conductivity between the electrostatically adsorbed plate sample and the temperature controller is not sufficient,
Moreover, there is a problem that the plasma permeability is poor. Further, in the electrostatic chuck of the second example, since it is necessary to bond two plate-like bodies, that is, an insulating dielectric plate and an insulating plate, it is difficult to achieve high processing accuracy, and therefore, the production yield is low. The manufacturing cost is increased, and since the insulating plate is present and the two bonding / joining layers are provided, the heat conductivity between the electrostatically adsorbed plate-shaped sample and the temperature control unit is not sufficient, and the plasma is not sufficient. There was a problem that the permeability was not sufficient.

An object of the present invention is to provide a simple and simple structure, easy manufacturing, high manufacturing yield and low manufacturing cost, and a heat transfer between the electrostatically attracted plate-like sample and the temperature control unit. An object of the present invention is to provide an electrostatic attraction device that improves conductivity, facilitates maintaining the temperature of a plate-like sample during processing at a desired constant temperature, and has good plasma permeability.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, have replaced the conventional insulating plate with a special organic compound to form the insulating layer. The present invention has been completed with the idea of forming. That is, the electrostatic chuck of the present invention covers at least an insulating dielectric layer on which a plate-shaped sample is placed, an electrode layer formed on the back surface of the insulating dielectric layer, and the electrode layer. An electrostatic adsorption device comprising: an insulator layer made of a polyimide resin; and a temperature controller bonded and joined to the insulator layer. By adopting such a configuration of the electrostatic chuck, the structure is simple and the manufacturing is easy. Therefore, the manufacturing yield is high and the manufacturing cost is low. Since the thermal conductivity is improved, it is easy to maintain the temperature of the plate-like sample during processing at a constant temperature, and it is possible to provide an electrostatic chuck having good plasma permeability.

As the organic compound used as the insulator layer in the present invention, a polyimide resin is preferable.
A polyimide resin having a withstand voltage of 50 kV / mm or more, a dielectric constant of 4 or less, and a dielectric loss tangent of 0.01 or less is preferable.
The thickness of the polyimide resin layer is 20 to 500 μm.
m is preferable. If a polyimide resin having such properties is used as the insulator layer, the insulator layer can be made thin because it has excellent dielectric breakdown resistance and plasma resistance, and the thermal conductivity is also kept good. Therefore, the temperature of the sample can be easily maintained at a constant temperature, and an electrostatic chuck having good plasma permeability can be obtained. In addition, since it is only necessary to apply a resin, the processing is extremely simple, which greatly contributes to cost reduction.

Further, the thickness of the insulating dielectric layer used in the present invention is preferably 0.5 to 4 mm. This is to ensure an appropriate withstand voltage, generate electrostatic force, and generate a sample adsorption force. In the present invention, it is preferable that the thickness of the electrode layer is 0.01 to 200 μm.
This is because the adhesion between the electrode layer and the insulator layer made of the polyimide resin is ensured, and the thermal conductivity with the temperature control unit is not impaired. Further, it is preferable that the insulator layer of the polyimide resin layer and the temperature control section are joined and adhered with an adhesive having rubber elasticity. With such a configuration, the effect of alleviating the stress due to the difference in thermal expansion between the polyimide resin layer having no rubber elasticity and the temperature control unit is exhibited, and the joining between the polyimide resin layer and the temperature control unit is performed. Has an effect that the sample temperature can be easily controlled because heat conduction is also improved.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an electrostatic chuck according to the present invention. The electrostatic chuck 1 includes an electrostatic chuck 2 and a metal temperature controller 3 having excellent thermal conductivity. ing. Here, the electrostatic chuck 2
Comprises an insulating dielectric layer 4 on which the plate-shaped sample 10 is placed, an electrode layer 5 formed on the back surface of the insulating dielectric layer 4,
It is composed of an insulator layer 6 made of a polyimide resin and covering the electrode layer 5, and is made of the metal temperature controller 3.
A circulation path 9 in which a coolant such as water or helium (He) gas circulates is formed inside. The electrostatic chuck 2 and the metal temperature controller 3 are
The side surfaces of the electrostatic chuck 2 including the bonding agent layer 7 are bonded with a coating material 8 having excellent plasma resistance. By applying a voltage to the electrode layer 5, the plate-like sample 1 is placed on the dielectric layer 4.
0 is electrostatically attracted.

The main components of the insulating dielectric layer 4 constituting the electrostatic chuck portion 2 are aluminum nitride, aluminum oxide, silicon nitride, silicon oxide, zirconium oxide,
It is desirable to use at least one or more ceramics selected from titanium oxide, sialon, boron nitride, and silicon carbide. Thus, the material of the dielectric layer 4 is
A single material or a different mixture may be used, but a material having a coefficient of thermal expansion as close as possible to the coefficient of thermal expansion of the electrode layer 5 and easy to sinter is preferable. Also, the dielectric layer 4
Is a material having a high dielectric constant, and it is desirable to select a material that does not become an impurity in a sample such as a semiconductor wafer to be adsorbed. The thickness of the dielectric layer 4 is 0.5 to 4 mm, particularly 0.7 to 2.0 mm.
It is preferably within the range of mm. If the thickness of the dielectric layer 4 is less than 0.5 mm, a sufficient withstand voltage cannot be ensured, so that it is not preferable. The thermal conductivity between the sample and the temperature control unit 3 is reduced, and it is difficult to maintain the temperature of the plate sample during processing at a desired constant temperature.

As a material of the electrode layer 5, a high melting point metal such as titanium, tungsten, molybdenum, platinum or the like, or a conductive ceramic such as graphite, carbon, silicon carbide, titanium nitride, titanium carbide or the like can be used. However, it is desirable that the thermal expansion coefficients of these electrode materials be as close as possible to the thermal expansion coefficients of the insulating dielectric layer 4 and the insulating layer 6 made of a polyimide resin described in detail below. The electrode layer 5 has a thickness of 0.01 to 200 μm.
m, particularly preferably in the range of 0.1 to 100 μm. If the film thickness is less than 0.01 μm, it is not preferable because sufficient conductivity cannot be secured. On the other hand, the film thickness is 3 μm
Is exceeded when the insulating layer 6 is formed by the polyimide resin, and the thermal conductivity between the plate-shaped sample placed on the dielectric layer 4 and the temperature control unit 3 is reduced. It is not preferable because the temperature decreases and it becomes difficult to maintain the temperature of the plate-like sample during processing at a desired constant temperature. Thus, a conductive film having such a thickness is easily formed by a sputtering method, an evaporation method, or a printing method. be able to. The sputtering method, the vapor deposition method, or the printing method may follow a conventional method.

The polyimide resin constituting the insulator layer 6 covering the electrode layer 5 preferably has a withstand voltage of 50 kV / mm or more, a dielectric constant of 4 or less, and a dielectric loss tangent of 0.01 or less. Corrosion resistance due to plasma and dielectric breakdown due to thermal degradation hardly occur, and plasma permeability is improved. Examples of such a polyimide-based resin include Iupikote (manufactured by Ube Industries, Ltd.) and uimide (manufactured by Unitika). The thickness of the insulator layer 6 is 20 to 500 μm, especially 50 to 3 μm.
It is preferably within the range of 00 μm. When the thickness of the insulator layer 6 is less than 20 μm, insulation and withstand voltage are reduced. For example, in the case of a bipolar electrostatic chuck, current leakage occurs between positive and negative electrodes, which is not preferable. If the thickness of the body layer 6 exceeds 500 μm, not only is it uneconomical, but also the thermal conductivity between the plate-shaped sample placed on the dielectric layer 4 and the temperature control unit 3 is reduced, and It is not preferable because it becomes difficult to maintain the temperature of the plate-like sample at a desired constant temperature.

The temperature control section 3 is not particularly limited as long as it is a material having excellent thermal conductivity and workability, and examples thereof include metals such as copper, aluminum, titanium, and stainless steel. . Further, it is preferable that the entire surface of the temperature control unit 3, at least the surface exposed to plasma, is subjected to alumite treatment or coating treatment with a polyimide resin. The alumite treatment or the coating treatment with a polyimide resin improves the plasma resistance of the temperature control unit 3, improves the plasma resistance (prevents abnormal discharge), and also prevents the occurrence of surface flaws. preferable. A circulation path 9 through which a coolant such as water or He gas circulates is formed inside the temperature control section 3, and the temperature of the plate-like sample being processed is maintained at a desired constant temperature. Control is performed.

The electrostatic chuck 2 and the temperature controller 3
Are bonded via the bonding agent layer 7. As a material (a bonding agent or an adhesive) constituting the bonding agent layer 7,
There is no particular limitation as long as the electrostatic chuck 2 and the temperature controller 3 can be firmly joined.
An organic adhesive having rubber elasticity is preferably used. That is, since the polyimide resin constituting the insulator layer 6 does not have rubber elasticity, it is difficult to firmly bond and bond the electrostatic chuck unit 2 and the temperature control unit 3 with a bonding agent having no rubber elasticity. Becomes In addition, since the bonding agent having rubber elasticity has rubber elasticity, it also functions as a thermal expansion relaxation layer, and is preferable because the bonding agent layer 7 does not deteriorate due to thermal stress. When the plasma resistance of the bonding agent layer 7 is not sufficient, it is preferable to protect the side surface of the bonding agent layer 7 by coating the side surface of the bonding agent layer 7 with a metal or inorganic coating material 8 having excellent plasma resistance. . Examples of the bonding agent having rubber elasticity include a silicone bonding agent and a Teflon (registered trademark) bonding agent.
Examples of the metal-based or inorganic-based coating material 8 include indium and silicone-based coating materials.

[0015]

The insulating layer is made of a polyimide resin having excellent properties such as high withstand voltage, low dielectric constant and low dielectric loss tangent, instead of the conventional insulating plate.

[0016]

As described in detail above, the electrostatic chuck according to the present invention comprises an insulating dielectric layer on which a plate-like sample is placed, and an electrode formed on the back surface of the insulating dielectric layer. Layer, an insulator layer made of a polyimide resin covering the electrode layer,
The provision of the temperature control section bonded and bonded to the insulator layer makes the structure simple and simple, easy to manufacture, high in manufacturing yield, and low in manufacturing cost. In addition, since the thickness of the plate sample and the temperature control unit can be reduced, the thermal conductivity between the electrostatically attracted plate sample and the temperature control unit is improved, and the temperature of the plate sample being processed is reduced. It is easy to maintain the desired constant temperature, and it is possible to provide an electrostatic chuck having good plasma permeability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an electrostatic suction device according to the present invention.

[Explanation of symbols]

1 ····· Electrostatic suction device, 2 ···· Electrostatic chuck part, 3 ····
.Temperature control section, 4... Dielectric layer, 5... Electrode layer, 6.
..Insulator layer, 7 ... Bonding agent layer, 8 ... Coating material, 9 ... Circulation path, 10 ... Plate sample

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akiyasu Fujita 585 Tomimachi, Funabashi-shi, Chiba F-term (reference) in the New Materials Division, Sumitomo Osaka Cement Co., Ltd. 3C016 GA10 5F031 HA02 HA03 HA16 HA38

Claims (6)

[Claims] 1. A dielectric layer on which at least a plate-shaped sample is placed, an electrode layer formed on a back surface of the dielectric layer, and an insulator layer made of a polyimide resin that covers the electrode layer.
A temperature controller bonded and bonded to the insulator layer. 2. The polyimide resin constituting the insulator layer has a withstand voltage of 50 kV / mm or more, a dielectric constant of 4 or less, and a dielectric loss tangent of 0.01 or less.
3. The electrostatic suction device according to claim 1. 3. The insulating layer has a thickness of 20 to 500 μm.
The electrostatic attraction device according to claim 1, wherein 4. The electrode layer has a thickness of 0.01 to 200 μm.
2. The electrostatic chuck according to claim 1, wherein m is m. 5. The electrostatic chuck according to claim 1, wherein the thickness of the dielectric layer is 0.5 to 4 mm. 6. The electrostatic attraction device according to claim 1, wherein the insulator layer and the temperature control unit are joined and adhered with an adhesive having rubber elasticity.