JP2008042140A - Electrostatic chuck device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic chuck device which equalizes plasma density without the possibility of having an influence such as disturbance on the plasma distribution on the surface of a plate-like specimen, and as a result, implements uniform plasma processing over the entire surface of the plate-like specimen. <P>SOLUTION: The electrostatic chuck device is provided with: an electrostatic chuck section provided with a substrate using its surface as a placing surface for placing the plate-like specimen and having a built-in internal electrode 25 for electrostatic adsorption, and a power feeding terminal for applying a DC voltage to the internal electrode 25; and a metal base section fixed and integrated on the electrostatic chuck section and used as an electrode for generating high frequency. The internal electrode 25 consists of one or more electrode portions 29. Out of distances between two points in the inside of the electrode portion 29, a resistance value in the shortest distance L connecting a point 29a nearest to a center axis A of the substrate and the point 29b farthest from the center axis A is 10<SP>2</SP>Ω-10<SP>10</SP>Ω. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic chuck device, and more particularly, a high frequency discharge method in which a plasma is generated by applying a high frequency to an electrode and a plate-like sample such as a semiconductor wafer, a metal wafer, or a glass plate is subjected to the plasma. The present invention relates to an electrostatic chuck device suitable for use in a plasma processing apparatus.

  Conventionally, in processing such as etching, deposition, oxidation, sputtering, etc. in the manufacturing process of semiconductor devices such as IC, LSI, VLSI, or flat panel displays (FPD) such as liquid crystal displays, the processing gas is relatively low temperature. In order to make a good reaction, a lot of plasma is used. In general, plasma processing apparatuses are roughly classified into a method using glow discharge or high-frequency discharge and a method using microwaves as a method for generating plasma.

FIG. 11 is a cross-sectional view showing an example of an electrostatic chuck device mounted on a conventional high-frequency discharge type plasma processing apparatus. The electrostatic chuck device 1 is provided at a lower portion of a chamber (not shown) that also serves as a vacuum container. The electrostatic chuck unit 2 is provided and the metal base unit 3 is fixed to and integrated with the bottom surface of the electrostatic chuck unit 2.
The electrostatic chuck unit 2 has an upper surface as a mounting surface 4a on which a plate-like sample W such as a semiconductor wafer is mounted and electrostatically attracts, and a substrate 4 having an internal electrode 5 for electrostatic adsorption, The power supply terminal 6 is configured to apply a DC voltage to the suction internal electrode 5, and a DC power supply 7 that applies a DC voltage is connected to the power supply terminal 6. The metal base portion 3 also serves as a high-frequency generating electrode (lower electrode), and is connected to a high-frequency voltage generating power source 8 and a flow path 9 for circulating a cooling medium such as water or an organic solvent is formed therein. Has been. The chamber is grounded.

In this electrostatic chuck device 1, a plate-like sample W is placed on the placement surface 4 a, and a DC voltage is applied to the internal electrode 5 for electrostatic attraction via a power supply terminal 6 by a DC power source 7. The sample W is electrostatically adsorbed. Next, the inside of the chamber is evacuated to introduce a processing gas, and a high frequency voltage is applied between the metal base portion 3 and the chamber by the high frequency voltage generating power source 8 to generate a high frequency electric field in the chamber. As the high frequency, a frequency in the region of 27 MHz or less is generally used.
Electrons are accelerated by the high-frequency electric field, and plasma is generated by impact ionization of the electrons and the processing gas, and various treatments can be performed by the plasma.

By the way, recently, as the design rule in the manufacturing process is miniaturized, high-density plasma processing under a low pressure is required also in plasma processing. In the above-described high-frequency discharge type plasma processing apparatus, 50 MHz or more is conventionally required. The frequency in the high frequency region is much higher than that of the conventional frequency.
When the frequency of the high frequency discharge increases, when a high frequency voltage is applied to the metal base portion, a current flows from the peripheral portion of the surface of the metal base portion toward the center portion due to the skin effect. Accordingly, the electric field strength at the center of the surface of the metal base portion is higher than the electric field strength at the peripheral portion, and the density of the generated plasma is higher at the central portion side of the metal base portion than at the peripheral portion side, and the plasma density is high. The plasma resistivity is low at the center of the metal base.
As a result, the non-uniformity of the plasma density on the surface of the metal base portion is further increased, and there has been a problem that a uniform plasma treatment cannot be performed on the plate-like sample.

In order to solve this problem, an electrostatic chuck device shown in FIG. 12 has been proposed (Patent Document 1).
In this electrostatic chuck device 11, a large number of convex portions 13 are discretely formed on the surface of a disk-shaped metal plate 12 that also serves as a high-frequency generating electrode, and the entire surface of the metal plate 12 including these convex portions 13 is formed. An alumina (Al ₂ O ₃ ) sprayed film 14 as a dielectric is formed, and an internal electrode 15 for electrostatic adsorption is built in the alumina sprayed film 14, and the surface of the alumina sprayed film 14 is a plate shape such as a semiconductor wafer. It is set as the mounting surface 14a which mounts the sample W and carries out electrostatic adsorption.
In this electrostatic chuck device 11, when a high frequency voltage is applied to the metal plate 12, the alumina (Al ₂ O ₃ ) embedded in the recesses between the protrusions 13 causes the current to flow to the surface of the metal base portion due to the skin effect. Therefore, the electric field strength on the surface of the metal base portion is made uniform, and as a result, the plasma density is made uniform.
JP 2004-363552 A

However, in the conventional electrostatic chuck device 11 described above, the concave portions between the convex portions 13 are filled with alumina (Al ₂ O ₃ ) by a thermal spraying method, and thus the depth of the concave portions is naturally limited. Yes, usually about 1 mm. Therefore, in the thermal spraying method, the concave portion cannot be filled with molten alumina (Al ₂ O ₃ ) at a high density, and current flows from the peripheral portion of the surface of the metal base portion toward the central portion due to the skin effect. There is a disadvantage that it cannot be effectively prevented.

  The present invention has been made in view of the above circumstances, and can effectively prevent the current from flowing from the peripheral portion of the surface of the metal base portion toward the central portion due to the skin effect. The plasma distribution on the surface of the plate-like sample is not affected by disturbances, and the plasma density can be made uniform. As a result, electrostatic discharge can be applied over the entire surface of the plate-like sample. An object is to provide a chuck device.

As a result of intensive studies to solve the above-mentioned problems, the present inventors configured an electrostatic adsorption internal electrode built in the substrate by one or more electrode parts, and between the two points inside the electrode part. Of the distances, if the resistance value connecting the point corresponding to the center axis of the substrate or the point closest to the center axis and the point farthest from the center axis is 10 ² Ω or more and 10 ¹⁰ Ω or less, As a result, the present invention has been completed.

That is, the electrostatic chuck device of the present invention has a main surface as a mounting surface on which a plate-like sample is mounted and a substrate with a built-in electrostatic adsorption internal electrode, and a DC voltage applied to the electrostatic adsorption internal electrode. An electrostatic chuck portion including a power supply terminal for applying a voltage, and a metal base portion fixed to and integrated with another main surface of the base body of the electrostatic chuck portion, and serving as a high-frequency generating electrode, The internal electrode for electrostatic attraction is composed of one or more electrode portions, and of the distance between two points inside the electrode portion, the point corresponding to the center axis of the substrate or the point closest to the center axis, The resistance value connecting the farthest point to the central axis is 10 ² Ω or more and 10 ¹⁰ Ω or less.

In this electrostatic chuck device, the internal electrode for electrostatic attraction is composed of one or more electrode portions, and the distance between two points inside each of the one or more electrode portions corresponds to the central axis of the base. When the resistance value connecting the point to be or the point closest to the central axis and the point farthest from the central axis is 10 ² Ω or more and 10 ¹⁰ Ω or less, a high-frequency current for generating plasma is electrostatically The flow from the peripheral edge portion of the electrostatic chuck portion toward the central portion is prevented through the suction internal electrode. As a result, the plasma density on the surface of the plate-like sample is made uniform, and uniform plasma treatment is performed over the entire surface of the plate-like sample.

According to the electrostatic chuck device of the present invention, the internal electrode for electrostatic attraction is constituted by one or more electrode portions, and the distance between the two points within each of the one or more electrode portions is the same as that of the substrate. Since the resistance value connecting the point corresponding to the central axis or the point closest to the central axis and the point farthest from the central axis is 10 ² Ω or more and 10 ¹⁰ Ω or less, a high-frequency current for generating plasma Can be prevented from flowing from the peripheral edge portion of the electrostatic chuck portion toward the central portion through the internal electrode for electrostatic attraction. Therefore, the plasma density on the surface of the plate-like sample can be made uniform, and as a result, uniform plasma treatment can be performed over the entire surface of the plate-like sample. In addition, the electrostatic attraction force is expressed and responsive.

The best mode for carrying out the electrostatic chuck device of the present invention will be described.
The following embodiments are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

[First Embodiment]
FIG. 1 is a cross-sectional view showing a monopolar electrostatic chuck device according to a first embodiment of the present invention. This electrostatic chuck device 21 includes an electrostatic chuck portion 22, a metal base portion 23, and a dielectric. The body plate 24 is constituted.
The electrostatic chuck portion 22 has a disk-like base 26 having an upper surface (one main surface) on which the plate-like sample W is placed and a built-in electrostatic adsorption internal electrode 25, and the electrostatic adsorption inner portion. The power supply terminal 27 applies a DC voltage to the electrode 25.

The base body 26 has a disk-shaped mounting plate 31 whose upper surface (one main surface) 31a is a mounting surface for mounting a plate-shaped sample W such as a semiconductor wafer, a metal wafer, a glass plate, and the like. A disk-shaped support plate 32 disposed opposite to the lower surface (another main surface) of the mounting plate 31; and an electrostatic chucking internal electrode 25 sandwiched between the mounting plate 31 and the support plate 32. Is the main constituent.
An insulating material layer 33 is formed on the outer peripheral side of the electrostatic adsorption internal electrode 25 and a circular opening at the center position thereof.

FIG. 2 is a cross-sectional view showing a state in which the electrostatic adsorption internal electrode 25 is formed on the support plate 32 constituting the base body 26. The electrostatic adsorption internal electrode 25 is a disc-shaped electrode portion. It is composed of one electrode portion 29 having a circular opening 30 formed at the center position, and of the distance between two points inside the electrode portion 29, the point 29a closest to the central axis A of the base 26 and The resistance value at the shortest distance L connecting the point farthest from the central axis A, that is, the point 29b closest to the peripheral edge of the substrate 26, is 10 ² Ω or more and 10 ¹⁰ Ω or less.

On the other hand, in the metal base portion 23, a flow path 28 for circulating a cooling medium such as water or an organic solvent is formed therein, and the temperature of the plate sample W placed on the placement surface is set to a desired value. It is comprised so that it can be maintained at temperature. The metal base portion 23 also serves as a high frequency generating electrode.
A circular concave portion 35 is formed on the surface (main surface) of the metal base portion 23 on the electrostatic chuck portion 22 side, and a dielectric is formed in the concave portion 35 via an insulating adhesive / bonding agent layer 36. The plate 24 is bonded and fixed, and the dielectric plate 24 and the support plate 32 of the electrostatic chuck portion 22 are bonded and bonded via an insulating bonding / bonding agent layer 36.

Further, a power feeding terminal insertion hole 37 is formed in the vicinity of the central portion of the support plate 32 and the metal base portion 23, and a DC voltage is applied to the electrostatic suction internal electrode 25 in the power feeding terminal insertion hole 37. A power supply terminal 27 is inserted through a cylindrical insulator 38. The upper end of the power feeding terminal 27 is electrically connected to the electrostatic adsorption internal electrode 25.
Further, the mounting plate 31, the support plate 32, the dielectric plate 24, the electrostatic adsorption internal electrode 25, and the metal base portion 23 are formed with a cooling gas introduction hole 39 penetrating them. Thus, a cooling gas such as He is supplied to the gap between the mounting plate 31 and the lower surface of the plate-like sample W.

An upper surface 31a of the mounting plate 31 is an electrostatic adsorption surface on which a single plate-like sample W is mounted and electrostatically adsorbs the plate-like sample W by electrostatic adsorption force. ) 31a is provided with a plurality of cylindrical protrusions (not shown) having a substantially circular cross section along the upper surface 31a, and the top surfaces of these protrusions are parallel to the upper surface 31a.
In addition, a wall (not shown) that is continuous along the peripheral edge and has the same height as the protrusion is provided at the peripheral edge of the upper surface 31a so that a cooling gas such as He does not leak. It is formed so as to go around the peripheral edge of the upper surface 31a.

  The electrostatic chuck device 21 configured as described above is mounted in a chamber of a plasma processing apparatus such as a plasma etching apparatus, and a plate-like sample W is mounted on an upper surface 31a which is a mounting surface, and an electrostatic chucking inner part is mounted. By applying a predetermined DC voltage to the electrode 25 via the power feeding terminal 27, the plate-like sample W is adsorbed and fixed using electrostatic force, and the metal base portion 23 also serving as a high-frequency generating electrode and the chamber By applying a high-frequency voltage between them to generate plasma on the mounting plate 31, the plate-like sample W can be subjected to various plasma treatments.

Next, each component of the electrostatic chuck device will be described in more detail.
"Mounting plate and support plate"
Both the mounting plate 31 and the support plate 32 are made of ceramics.
Examples of the ceramic include aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), zirconium oxide (ZrO ₂ ), sialon, boron nitride (BN), and silicon carbide (SiC). The selected one type of ceramics or composite ceramics containing two or more types is preferred.

The material constituting these may be a single material or a mixture, but the thermal expansion coefficient approximates the thermal expansion coefficient of the electrostatic adsorption internal electrode 25 as much as possible, and is sintered. What is easy to do is preferable. Further, since the upper surface 31a side of the mounting plate 31 is an electrostatic adsorption surface, it is preferable to select a material that has a particularly high dielectric constant and does not become an impurity with respect to the plate-like sample W that is electrostatically adsorbed. .
In consideration of the above, the mounting plate 31 and the support plate 32 are substantially composed of a silicon carbide-aluminum oxide composite sintered body containing 1% to 20% by weight of silicon carbide and the balance being aluminum oxide. preferable.

As this silicon carbide-aluminum oxide composite sintered body, a composite sintered body composed of aluminum oxide (Al ₂ O ₃ ) and silicon carbide (SiC) whose surface is coated with silicon oxide (SiO ₂ ) is used. When the content of SiC) is 5% by weight or more and 15% by weight or less with respect to the entire composite sintered body, the volume resistivity at room temperature (25 ° C.) is 1.0 × 10 ¹⁴ Ω · cm or more, and Coulomb It is suitable as a mounting plate 31 for a type electrostatic chuck device. Furthermore, it has excellent wear resistance, does not cause wafer contamination or particle generation, and has improved plasma resistance.

Moreover, as this silicon carbide-aluminum oxide composite sintered body, a composite sintered body made of aluminum oxide (Al ₂ O ₃ ) and silicon carbide (SiC) is used, and the content of silicon carbide (SiC) is changed to a composite sintered body. When it is 5 wt% or more and 15 wt% or less with respect to the whole, the volume resistivity at room temperature (25 ° C.) is 1.0 × 10 ⁹ Ω · cm or more and 1.0 × 10 ¹² Ω · cm or less, It is suitable as the mounting plate 31 of the Johnson-Rahbek type electrostatic chuck device. Furthermore, it has excellent wear resistance, does not cause wafer contamination or particle generation, and has improved plasma resistance.

Moreover, the average particle diameter of the silicon carbide particles in this silicon carbide-aluminum oxide composite sintered body is preferably 0.2 μm or less.
When the average particle diameter of the silicon carbide particles exceeds 0.2 μm, the electric field during plasma irradiation concentrates on the silicon carbide particles in the silicon carbide-aluminum oxide composite sintered body, and the periphery of the silicon carbide particles is damaged. It is because it becomes easy.

The average particle diameter of the aluminum oxide particles in the silicon carbide-aluminum oxide composite sintered body is preferably 2 μm or less.
This is because if the average particle diameter of the aluminum oxide particles exceeds 2 μm, the silicon carbide-aluminum oxide composite sintered body is plasma-etched, and it becomes easy to form sputter marks and the surface roughness becomes rough.

"Electrode for electrostatic adsorption"
The internal electrode 25 for electrostatic attraction is formed by forming a circular opening 30 at the center position of an electrode portion 29 made of a disk-shaped ceramic having a thickness of about 10 μm to 50 μm. The height is appropriately adjusted in accordance with the shape and size of the plate-like sample W to be placed. Of the distance between two points inside the electrode portion 29, the point 29a closest to the central axis A of the base 26 is The resistance value at the shortest distance L connecting the point farthest from the central axis A, that is, the point 29b closest to the peripheral edge of the substrate 26, is preferably 10 ² Ω or more and 10 ¹⁰ Ω or less, more preferably It is 10 ² Ω or more and 10 ⁸ Ω or less, more preferably 10 ³ Ω or more and 10 ⁶ Ω or less.

Here, the reason why the resistance value at the shortest distance L is limited as described above is that when the resistance value at the shortest distance L is less than 10 ² Ω, a high-frequency current for generating plasma causes the internal electrode 25 for electrostatic adsorption to be generated. This is because the plasma flows from the peripheral edge portion of the electrostatic chuck portion 22 toward the center portion, and thus the plasma cannot be made uniform. On the other hand, when the resistance value at the shortest distance L exceeds 10 ¹⁰ Ω. The electrostatic adsorption internal electrode 25 is substantially an insulator, and cannot function as an electrostatic adsorption internal electrode, and does not exhibit electrostatic adsorption force, or is responsive to electrostatic adsorption force. This is because it takes a long time until the required electrostatic attraction force is developed.

As the ceramic constituting the internal electrode 25 for electrostatic attraction, conductive ceramics having expansion coefficients approximate to the expansion coefficients of the mounting plate 31 and the support plate 32 are preferable. Examples include ligation.
(1) A composite sintered body obtained by adding semiconductor ceramics such as silicon carbide (SiC) to insulating ceramics such as aluminum oxide.
(2) A composite sintered body obtained by adding conductive ceramics such as tantalum carbide (TaC), tantalum nitride (TaN), molybdenum carbide (Mo ₂ C) to insulating ceramics such as aluminum oxide.
(3) A composite sintered body obtained by adding a high melting point metal such as molybdenum (Mo), tungsten (W), or tantalum (Ta) to an insulating ceramic such as aluminum oxide.

"Insulation layer"
The insulating material layer 33 is for joining and integrating the mounting plate 31 and the support plate 32, and for protecting the electrostatic adsorption internal electrode 25 from plasma and corrosive gas. As a material constituting the insulating material layer 33, a high resistance body having the same main component as the mounting plate 31 and the support plate 32 and having a resistance value larger than that of the material constituting the electrostatic adsorption internal electrode 25 is preferable. More preferably, it is an insulator.

For example, when the mounting plate 31, the support plate 32, and the electrostatic adsorption internal electrode 25 are formed of a silicon carbide-aluminum oxide composite sintered body, the silicon carbide content is lower than that of the composite sintered body. It is preferable to use a silicon carbide-aluminum oxide composite sintered body or aluminum oxide (Al ₂ O ₃ ).

"Dielectric plate"
The dielectric plate 24 is used to prevent the current from flowing from the peripheral portion toward the center portion through the surface of the metal base portion 23 due to the skin effect by applying a high frequency voltage to the metal base portion 23. A disk-shaped member in which a feeding terminal insertion hole 37 is formed in the vicinity of the center. Such a dielectric plate 24 is preferably a ceramic having excellent insulation and good thermal conductivity, such as an aluminum oxide (Al ₂ O ₃ ) sintered body, an aluminum nitride (AlN) sintered body, and the like. Can be mentioned.

The thickness of the dielectric plate 24 is preferably 2 mm or more and 15 mm or less, more preferably 4 mm or more and 8 mm or less.
When the thickness of the dielectric plate 24 is less than 2 mm, the high-frequency current applied to the metal base portion 23 is transmitted through the surface of the metal base portion 23 by the skin effect and is prevented from flowing from the peripheral portion toward the center portion. On the other hand, if the thickness of the dielectric plate 24 exceeds 15 mm, the thermal conductivity from the metal base portion 23 to the plate-like sample W decreases, and the plate-like sample W is maintained at a desired constant temperature. Becomes difficult.

The insulating adhesive / bonding agent layer 36 for adhering / bonding the dielectric plate 24 and the support plate 32 of the electrostatic chuck portion 22 is not particularly limited as long as it has excellent insulating properties. a material obtained by adding insulating ceramic in which aluminum nitride (AlN) powder and alumina (Al 2 _{0 3)} powder in a silicone-based adhesive is preferably used.
Here, the reason why the insulating adhesive / bonding agent layer 36 is used is that, instead of the insulating adhesive / bonding agent layer 36, the dielectric plate 24 and the support plate 32 are interposed via the conductive adhesive / bonding agent layer 36. When a high frequency voltage is applied to the metal base portion 23 through the conductive adhesive / bonding agent layer, current is transmitted through the surface of the metal base portion 23 by the skin effect and from the peripheral portion to the central portion. This is because it becomes impossible to achieve uniform plasma.

  Here, the dielectric plate 24 and the recess 35 are bonded and fixed through an insulating adhesive / bonding agent layer 36, but the fixing method of the dielectric plate 24 and the recess 35 is not particularly limited, For example, it may be configured to be bonded and fixed through a conductive bonding / bonding agent layer, or the bonding / bonding portion between the dielectric plate 24 and the concave portion 35 is made into a complementary shape so that the dielectric plate 24 and the concave portion 35 It is good also as a structure which fits.

"Manufacturing method of electrostatic chuck device"
A method for manufacturing the electrostatic chuck device of this embodiment will be described.
Here, the case where the mounting plate 31 and the support plate 32 are manufactured using a silicon carbide-aluminum oxide composite sintered body substantially containing 1 wt% to 20 wt% silicon carbide will be described as an example.
As the raw material powder of silicon carbide (SiC) to be used, it is preferable to use silicon carbide powder having an average particle size of 0.1 μm or less.

The reason is that when the average particle diameter of silicon carbide (SiC) powder exceeds 0.1 μm, the obtained silicon carbide-aluminum oxide composite sintered body has an average particle diameter of silicon carbide particles exceeding 0.2 μm. This is because the effect of improving the strength of the mounting plate 31 and the support plate 32 is reduced.
In addition, the mounting plate 31 made of this silicon carbide-aluminum oxide composite sintered body is easily damaged when the electric field is concentrated on the silicon carbide (SiC) particles when exposed to plasma. This is because the electrostatic adsorption force after plasma damage may be reduced.

As this silicon carbide (SiC) powder, a powder obtained by a plasma CVD method is preferable, and in particular, a silane compound or silicon halide and hydrocarbon source gas is introduced into the plasma in a non-oxidizing atmosphere, and the reaction system Ultrafine powder having an average particle diameter of 0.1 μm or less obtained by performing a gas phase reaction while controlling the pressure in the range of 1 × 10 ⁵ Pa (1 atm) to 1.33 × 10 Pa (0.1 Torr) However, it is preferable since it has excellent sinterability, high purity, and good particle dispersibility during molding due to its spherical shape.

On the other hand, the raw material powder of aluminum oxide _(Al 2 _{0 3),} the following aluminum oxide average particle diameter of 1μm _(Al 2 _{0 3)} is preferably used powder.
The reason is that aluminum oxide (Al 2 _{0 3)} silicon carbide was obtained using a powder having an average particle size exceeds 1 [mu] m - In the aluminum oxide composite sintered body, aluminum oxide in the composite sintered body (Al ₂ 0 ₃ ) Since the average particle diameter of the particles exceeds 2 μm, the upper surface 31a on the side of the mounting plate 31 on which the plate-like sample is mounted is easily etched by the plasma, and thus a sputter mark is formed. This is because the surface roughness of the upper surface 31a becomes rough, and the electrostatic chucking force of the electrostatic chuck device 21 may be reduced.
The aluminum oxide (Al ₂ O ₃ ) powder used is not particularly limited as long as it has an average particle diameter of 1 μm or less and high purity.

Next, the above-mentioned silicon carbide (SiC) powder and aluminum oxide (Al ₂ 0 ₃ ) powder are mixed in a ratio that provides a desired volume resistivity value, for example, 1 to 12% by weight of silicon carbide (SiC) powder, the balance Is weighed and mixed so as to become aluminum oxide (Al ₂ O ₃ ) powder.
Next, the obtained mixed powder is molded into a predetermined shape using a mold, and then the obtained molded body is pressed using, for example, a hot press (HP) or a hot isostatic press (HIP). Firing while pressing to obtain a silicon carbide-aluminum oxide composite sintered body.

  For example, as a condition when using a hot press (HP), the applied pressure is not particularly limited. However, when obtaining a silicon carbide-aluminum oxide composite sintered body, for example, 5 to 40 MPa is used. preferable. This is because if the pressing force is less than 5 MPa, a composite sintered body having a sufficiently dense sintering density cannot be obtained, whereas if the pressing force exceeds 40 MPa, a jig made of graphite or the like is deformed and worn.

Moreover, as a temperature at the time of baking, 1650-1850 degreeC is preferable. When the firing temperature is less than 1650 ° C., a sufficiently dense silicon carbide-aluminum oxide composite sintered body cannot be obtained. On the other hand, when the firing temperature exceeds 1850 ° C., the components contained in the molded body are decomposed during the firing process. This is because grain growth tends to occur.
Moreover, as an atmosphere at the time of baking, inert atmospheres, such as argon atmosphere and nitrogen atmosphere, are preferable from a viewpoint of preventing the oxidation of silicon carbide.
Of the two silicon carbide-aluminum oxide composite sintered bodies thus obtained, a power supply terminal insertion hole 37 is formed by machining in a predetermined position of one composite sintered body, To do.

In addition, as a coating agent for forming the internal electrode 25 for electrostatic adsorption, an insulating ceramic such as aluminum oxide, tantalum carbide (TaC), tantalum nitride (TaN), molybdenum carbide (Mo ₂ C), molybdenum (Mo ), Tungsten (W), tantalum (Ta), etc. are added at such a ratio that the resistance value at the shortest distance L connecting the points 29a and 29b of the electrode portion 29 is 10 ² Ω or more and 10 ¹⁰ Ω or less. An internal electrode forming coating agent is prepared, and this internal electrode forming coating agent is applied to a region of the support plate 32 where the electrostatic adsorption internal electrode is to be formed to form an electrode layer.

  Further, as a coating agent for forming the insulating material layer 33, for example, the main component is the same as that of the mounting plate 31 and the support plate 32, and the resistance value is larger than the material constituting the internal electrode 25 for electrostatic adsorption. An insulating material layer forming coating agent containing an insulating material is prepared, and this insulating material layer forming coating agent is applied to a portion other than the region where the internal electrode for electrostatic adsorption is formed to form an insulating material layer. To do.

  Next, the power supply terminal 27 is inserted into the power supply terminal insertion hole 37 of the support plate 32 via the cylindrical insulator 38, the surface of the support plate 32 on which the electrode layer and the insulating material layer are formed, The plate 31 is overlaid, and then the mounting plate 31 and the support plate 32 are pressurized while being heated to, for example, 1600 ° C. or more, and the internal electrode 25 for electrostatic adsorption is formed by the above electrode layer and bonded. An insulating material layer 33 to be a layer is formed, and the mounting plate 31 and the support plate 32 are joined via the internal electrode 25 for electrostatic adsorption and the insulating material layer 33. Then, the upper surface 31a of the mounting plate 31 serving as the mounting surface is polished so that Ra (center line average roughness) is 0.3 μm or less to form the electrostatic chuck portion 22.

On the other hand, an aluminum (Al) plate is used to produce a metal base portion 23 in which a circular recess 35 is formed on the surface and a flow path 28 for circulating a cooling medium is formed inside. Further, aluminum oxide (Al ₂ O ₃ ) powder is molded and fired to produce a dielectric plate 24 made of an aluminum oxide sintered body.
Next, an insulating adhesive / bonding agent is applied to the entire inner surface of the concave portion 35 of the metal base portion 23, and then the dielectric plate 24 is bonded / bonded onto the insulating adhesive / bonding agent. An insulating adhesive / bonding agent is applied on the metal base portion 23 including 24, and the electrostatic chuck portion 22 is bonded / bonded onto the insulating adhesive / bonding agent.

In this bonding / bonding process, the dielectric plate 24 is bonded and fixed in the recess 35 of the metal base portion 23 via an insulating bonding / bonding agent layer 36, and the support plate 32 of the electrostatic chuck portion 22 is It is bonded and fixed to the metal base portion 23 and the dielectric plate 24 through an insulating bonding / bonding agent layer 36.
As described above, the electrostatic chuck device of this embodiment can be obtained.

As described above, according to the electrostatic chuck device of this embodiment, the point 29a closest to the central axis A of the base body 26 among the distances between the two points inside the electrode portion 29 of the internal electrode 25 for electrostatic attraction. And the resistance value at the shortest distance L connecting the point farthest from the central axis A, that is, the point 29b closest to the peripheral edge of the base body 26, is 10 ² Ω or more and 10 ¹⁰ Ω or less. It is possible to prevent the high-frequency current from flowing from the peripheral edge portion of the electrostatic chuck portion 22 toward the center portion via the internal electrode 25 for electrostatic attraction. Therefore, the plasma density on the surface of the plate-like sample W can be made uniform, and as a result, uniform plasma treatment can be performed over the entire surface of the plate-like sample W.

  In addition, the dielectric plate 24 is bonded and fixed in the concave portion 35 of the metal base portion 23 via an insulating adhesive / bonding agent layer 36, and the dielectric plate 24 and the support plate 32 of the electrostatic chuck portion 22 are connected. Since adhesion and fixing are performed via the insulating adhesive / bonding agent layer 36, the insulation between the metal base portion 23 and the electrostatic chuck portion 22 can be further enhanced. Therefore, when a high frequency voltage is applied to the metal base portion 23, it is possible to prevent a high frequency current from flowing through the electrostatic adsorption internal electrode 25, and to achieve uniform plasma. Therefore, uniform plasma treatment can be performed on the plate-like sample W.

[Second Embodiment]
FIG. 3 is a cross-sectional view showing a state in which the internal electrode for electrostatic attraction of the monopolar electrostatic chuck apparatus according to the second embodiment of the present invention is formed on the support plate 32 constituting the base body 26. The electrostatic chucking internal electrode 41 of the present embodiment is different from the electrostatic chucking internal electrode 25 of the first embodiment in that one electrode portion is arranged concentrically around the central axis A of the substrate. Are composed of three annular electrodes 42 to 44 different from each other, and a plurality of conductive connection portions 45 (eight in FIG. 3) that electrically connect the annular electrodes 42 to 44 to each other. is there.

Among the distances between the two points inside the electrode portion, the shortest distance connecting the point 42a closest to the central axis A of the substrate and the point furthest from the central axis A, that is, the point 44b closest to the peripheral edge of the substrate. It is formed so that the resistance value at L is 10 ² Ω or more and 10 ¹⁰ Ω or less.
In the internal electrode 41 for electrostatic attraction, the connection portion 45 is formed of a material having a resistance value of 10 ² Ω or more and 10 ⁹ Ω or less, and the annular electrodes 42 to 44 are made of a lower resistance material, for example, 10 Ω or less. The point 42a closest to the center axis A of the base and the point 44b farthest from the center axis A, that is, the point 44b closest to the peripheral edge of the base, of the distance between the two points inside the electrode part. It can be formed such that the resistance value at the shortest distance L to be connected is 10 ² Ω or more and 10 ¹⁰ Ω or less.
Also in the electrostatic adsorption internal electrode 41 of the present embodiment, the same effect as the electrostatic adsorption internal electrode 25 of the first embodiment can be obtained.

[Third Embodiment]
FIG. 4 is a cross-sectional view showing a state in which the internal electrode for electrostatic attraction of the monopolar electrostatic chuck apparatus according to the third embodiment of the present invention is formed on the support plate 32 constituting the base body 26. The electrostatic chucking internal electrode 51 of the present embodiment is different from the electrostatic chucking internal electrode 25 of the first embodiment in that one electrode portion is spiraled from the vicinity of the central axis A of the base toward the peripheral portion. This is a point constituted by one spiral electrode 52 extending in a shape.

Of the distance between the two points inside the spiral electrode 52, a point 52a closest to the central axis A of the base is connected to a point farthest from the central axis A, that is, a point 52b closest to the peripheral edge of the base. The spiral electrode 52 is formed so that the resistance value in the length direction is 10 ² Ω or more and 10 ¹⁰ Ω or less.
The electrostatic chucking internal electrode 51 of the present embodiment can achieve the same effects as the electrostatic chucking internal electrode 25 of the first embodiment.

[Fourth Embodiment]
FIG. 5 is a cross-sectional view showing a state in which the electrostatic attraction internal electrode of the bipolar electrostatic chuck apparatus according to the fourth embodiment of the present invention is formed on the support plate 32 constituting the base body 26. The internal electrode 61 for electrostatic attraction of the embodiment is different from the internal electrode 25 for electrostatic attraction of the first embodiment, because the internal electrode for electrostatic attraction has a bipolar electrode structure, so that it has a wide annular shape. The inner electrode for electrostatic attraction is divided into two by a straight line passing through the center point to form semicircular electrode portions 62, 63, with one semicircular electrode portion 62 as the positive electrode and the other semicircular electrode portion. This is a point where 63 is a negative electrode.

Of the distances between the two points inside each of these semicircular electrode portions 62 and 63, a point 62a (63a) closest to the central axis A of the base and a point farthest from the central axis A, that is, the base of the base The resistance value at the shortest distance L connecting the point 62b (63b) closest to the peripheral edge portion is formed to be 10 ² Ω or more and 10 ¹⁰ Ω or less.
The electrostatic chucking internal electrode 61 of the present embodiment can achieve the same effect as the electrostatic chucking internal electrode 25 of the first embodiment.

[Fifth Embodiment]
FIG. 6 is a cross-sectional view showing a state in which the internal electrode for electrostatic attraction of the bipolar electrostatic chuck device according to the fifth embodiment of the present invention is formed on the support plate 32 constituting the base body 26. The electrostatic adsorption internal electrode 71 of the embodiment is different from the electrostatic adsorption internal electrode 61 of the fourth embodiment in that the semicircular electrode portions 62 and 63 of the electrostatic adsorption internal electrode 61 are Further, it is divided into two by a straight line passing through the center point, and is divided into four in total to form quarter-circular electrode portions 72 to 75, and a pair of opposing quadrant-shaped electrode portions 72 and 74 are a positive electrode and another pair of opposing quadrants. This is a point where the circular electrode portions 73 and 75 are used as negative electrodes.

Of the distances between the two points inside each of these quarter-circular electrode portions 72 to 75, the point 72 a (73 a to 75 a) closest to the center axis A of the substrate and the point farthest from the center axis A, that is, It is formed such that the resistance value at the shortest distance L connecting the point 72b (73b to 75b) closest to the peripheral edge of the substrate is 10 ² Ω or more and 10 ¹⁰ Ω or less.
Also in the electrostatic adsorption internal electrode 71 of the present embodiment, the same effect as the electrostatic adsorption internal electrode 61 of the fourth embodiment can be obtained.

[Sixth Embodiment]
FIG. 7 is a cross-sectional view showing a state in which the internal electrode for electrostatic adsorption of the bipolar electrostatic chuck device according to the sixth embodiment of the present invention is formed on the support plate 32 constituting the base body 26. The electrostatic chucking internal electrode 81 of the embodiment is different from the electrostatic chucking internal electrode 51 of the third embodiment in that the electrostatic chucking internal electrode 51 has a pair of bipolar electrodes. The electrode portion is composed of two spiral electrodes 82 and 83 which are spirally extended from the vicinity of the central axis A of the base toward the peripheral portion and are fitted together so that one spiral electrode 82 is a positive electrode, The other point is that the other spiral electrode 83 is a negative electrode.

Of the distances between the two points inside each of the spiral electrodes 82 and 83, the point 82a (83a) closest to the central axis A of the substrate and the point farthest from the central axis A, that is, the peripheral edge of the substrate. The spiral electrode 82 (83) connecting the closest point 82b (83b) is formed so that the resistance value in the length direction is 10 ² Ω or more and 10 ¹⁰ Ω or less.
Also in the internal electrode 81 for electrostatic attraction of this embodiment, the same effect as the internal electrode 25 for electrostatic attraction of the first embodiment can be obtained.

[Seventh Embodiment]
FIG. 8 is a cross-sectional view showing a state in which the internal electrode for electrostatic attraction of the bipolar electrostatic chuck device according to the seventh embodiment of the present invention is formed on the support plate 32 constituting the base 26. The electrostatic chucking internal electrode 91 of the embodiment is different from the electrostatic chucking internal electrode 61 of the fourth embodiment in that each of the pair of electrode portions 92 and 93 has a plurality of arc shapes on both sides of the strip-shaped base portion 94. The other branch portions 95 are combined so that the respective branch portions 95 are fitted to each other, and one electrode portion 92 is a positive electrode and the other electrode portion 93 is a negative electrode.

Of the distances between the two points inside each of these electrode portions 92 and 93, the point 92a (93a) closest to the central axis A of the substrate and the point farthest from the central axis A, that is, the peripheral portion of the substrate are the most. The resistance value at the shortest distance L connecting the close point 92b (93b) is 10 ² Ω or more and 10 ¹⁰ Ω or less.
In the internal electrode 91 for electrostatic attraction, the resistance value of the band-shaped base portion 94 corresponding to the connection portion of the branch portion 95 on the arc is set to 10 ² Ω to 10 ¹⁰ Ω, and the branch portion 95 on the arc is, for example, It can be formed of a low resistance material of 10 ² Ω or less.
Also in the electrostatic adsorption internal electrode 91 of the present embodiment, the same effect as the electrostatic adsorption internal electrode 61 of the fourth embodiment can be obtained.

[Eighth Embodiment]
FIG. 9 is a cross-sectional view showing a state in which the electrostatic attraction internal electrode of the bipolar electrostatic chuck apparatus according to the eighth embodiment of the present invention is formed on the support plate 32 constituting the base body 26. The electrostatic chucking internal electrode 101 of the embodiment is different from the electrostatic chucking internal electrode 91 of the seventh embodiment in that a pair of electrode portions are constituted by comb-shaped electrode portions 102 and 103, and the comb-shaped electrode portions 102 and 103 are configured. Each has a plurality of strip-like branch portions 105 parallel to each other inside the arc-shaped base portion 104, and these electrode portions 102 and 103 are arranged to face each other so that the branch portions 105 are alternately arranged. The electrode portion 102 is a positive electrode and the other electrode portion 103 is a negative electrode.

Of the distances between the two points inside each of the comb-shaped electrode portions 102 and 103, the point 102a (103a) closest to the central axis A of the base and the point farthest from the central axis A, that is, the peripheral edge of the base It is formed so that the resistance value at the shortest distance L connecting the nearest point 102b (103b) is 10 ² Ω or more and 10 ¹⁰ Ω or less.
Also in the electrostatic attraction internal electrode 101 of the present embodiment, exactly the same effect as the electrostatic attraction internal electrode 91 of the seventh embodiment can be obtained.

[Ninth Embodiment]
FIG. 10 is a cross-sectional view illustrating a state in which the internal electrode for electrostatic attraction of the monopolar electrostatic chuck apparatus according to the ninth embodiment of the present invention is formed on the support plate 32 constituting the base body 26. The internal electrode 111 for electrostatic attraction of the present embodiment is different from the internal electrode 25 for electrostatic attraction of the first embodiment in that the electrostatic attraction internal electrode 111 is constituted by a disc-like electrode 112 arranged around the central axis A of the base. is there.

Of the distance between the two points inside the disc-shaped electrode 112, a point 112a corresponding to the central axis A of the substrate and a point farthest from the central axis A, that is, a point 112b closest to the peripheral edge of the substrate It is formed such that the resistance value at the shortest distance L to be connected is 10 ² Ω or more and 10 ¹⁰ Ω or less.
Also in the internal electrode 111 for electrostatic attraction of this embodiment, the same effect as the internal electrode 25 for electrostatic attraction of the first embodiment can be obtained.

It is sectional drawing which shows the electrostatic chuck apparatus of the 1st Embodiment of this invention. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 1st Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 2nd Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 3rd Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 4th Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state by which the internal electrode for electrostatic attraction of the 5th Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 6th Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 7th Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 8th Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows the state in which the internal electrode for electrostatic attraction of the 9th Embodiment of this invention was formed on the support plate which comprises a base | substrate. It is sectional drawing which shows an example of the conventional electrostatic chuck apparatus. It is sectional drawing which shows another example of the conventional electrostatic chuck apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Electrostatic chuck apparatus 22 Electrostatic chuck part 23 Metal base part 24 Dielectric board 25 Electrostatic adsorption internal electrode 26 Base 27 Power supply terminal 28 Flow path 31 Mounting plate 31a Upper surface 32 Support plate 33 Insulating material layer 35 Concave part 36 Insulating adhesive / bonding agent layer 37 Power supply terminal insertion hole 38 Insulator 39 Cooling gas introduction hole 41 Electrostatic adsorption internal electrode 42 to 44 Annular electrode 42a, 44b Point 45 Connection portion 46 Opening 51 Electrostatic adsorption internal electrode 52 Helical electrodes 52a, 52b Point 61 Electrostatic adsorption internal electrode 62, 63 Electrode part 62a, 63a, 62b, 63b Point 71 Electrostatic adsorption internal electrode 72-75 Electrode part 72a-75a, 72b-75b Point 81 Static Electroadsorption internal electrode 82, 83 Spiral electrode 82a, 83a, 82b, 83b Point 91 Electrostatic adsorption internal electrode 92, 93 electrode 92a, 93a, 92b, 93b Point 94 Base 95 Branch 101 Electrostatic adsorption internal electrode 102, 103 Comb electrode 102a, 103a, 102b, 103b Point 104 Base 105 Branch 111 Electrostatic adsorption internal electrode 112 Disc shape Electrode 112a, 112b Point A Center axis L Shortest distance W Plate specimen

Claims (1)

A static surface having a main surface as a mounting surface on which a plate-like sample is placed and a built-in electrostatic adsorption internal electrode, and a power supply terminal for applying a DC voltage to the electrostatic adsorption internal electrode. An electric chuck,
It is fixed to and integrated with the other main surface of the base of the electrostatic chuck portion, and includes a metal base portion that serves as a high-frequency generating electrode.
The internal electrode for electrostatic adsorption is composed of one or more electrode portions,
Of the distance between two points inside the electrode portion, a resistance value connecting a point corresponding to the central axis of the substrate or a point closest to the central axis and a point farthest from the central axis is 10 ² Ω or more And an electrostatic chuck device characterized by being 10 ¹⁰ Ω or less.

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