JP7772111B2 - Electrostatic Chuck Device - Google Patents

Description

The present invention relates to a susceptor and an electrostatic chuck device.

In recent years, dry etching equipment and CVD equipment used in the manufacturing process of semiconductors such as ICs, LSIs, and VLSIs have been increasingly used to process plate-like samples such as semiconductor wafers, liquid crystal glass substrates, and printed circuit boards one by one in order to uniformly perform etching or CVD film formation on each wafer. In this single-wafer process, the plate-like samples are placed on a sample stage (base) called a susceptor to hold each sample in the processing chamber and undergo the specified processing.
Since the susceptor must be able to withstand use in plasma and at high temperatures, it is required to have excellent plasma resistance and high thermal conductivity. As such a susceptor, a susceptor made of a ceramic sintered body, which has excellent plasma resistance and thermal conductivity, is used.

Some susceptors are equipped with internal electrodes, such as an electrostatic chuck electrode that generates an electric charge inside the susceptor to fix a plate-shaped sample by electrostatic attraction, a heater electrode that heats the plate-shaped sample by passing electricity through it, and a plasma generation electrode that passes high-frequency power through it to generate plasma for plasma processing (see, for example, Patent Document 1).

Figure 7 is a cross-sectional view showing an example of a susceptor incorporating an internal electrode as described above. The susceptor 600 shown in Figure 7 includes a mounting plate 601 on which a plate-shaped sample (not shown) is placed, a support plate 602 that supports the mounting plate 601, an internal electrode 603 that is sandwiched and held between the mounting plate 601 and the support plate 602, and power supply terminals 604, 604 that are embedded in the support plate 602 so as to contact the internal electrode 603 and supply current to the internal electrode 603.

A connection structure is known in which an electrode pin is pressed against a power supply terminal to connect the power supply terminal and the electrode pin in order to supply current to the power supply terminal (see, for example, Patent Document 2). This connection structure is effective in alleviating shear stress, which is applied to the connection between the power supply terminal and the electrode pin due to differences in the linear expansion coefficients of the mounting plate, support plate, internal electrode, etc.

Patent No. 3746935 Patent No. 6228031

However, with the connection structure of Patent Document 2, the electrode pin is pressed against the planar power supply terminal. When shear stress is applied to the connection due to differences in the linear expansion coefficients of the mounting plate, support plate, internal electrode, etc., the electrode pin tilts relative to the power supply terminal, changing the contact area between the power supply terminal and the electrode pin, making it impossible to supply the specified amount of current from the electrode pin to the power supply terminal.

The present invention was made in consideration of the above circumstances, and aims to provide a susceptor and an electrostatic chuck device including a susceptor that can suppress changes in the contact area between the power supply terminal and the electrode pin, even when shear stress caused by differences in the linear expansion coefficients of the mounting plate, support plate, internal electrode, etc. causes the electrode pin to tilt relative to the power supply terminal.

To solve the above problems, one aspect of the present invention provides a susceptor comprising an electrode provided inside a ceramic plate having a mounting surface on which a sample is placed, and a power supply terminal provided through the ceramic plate so as to contact the electrode, the surface opposite the mounting surface including at least the power supply terminal and having a recessed portion recessed toward the mounting surface.

In one aspect of the present invention, the cross-sectional shape of the inner surface of the recess in the thickness direction of the ceramic plate may be a curve or hyperbolic shape represented by at least one curvature or quadratic function.

In one aspect of the present invention, the inner surface may be coated with a metal layer.

In one aspect of the present invention, the arithmetic mean roughness (Ra) of the surface of the metal layer opposite the inner surface may be 2 μm or more and 30 μm or less.

In one aspect of the present invention, the electrode and the power supply terminal may be a composite of an insulating material and a conductive material.

In one aspect of the present invention, the insulating material may be at least one selected from the group consisting of aluminum oxide, aluminum nitride, silicon nitride, yttrium (III) oxide, yttrium aluminum garnet, and _SmAlO3 .

In one aspect of the present invention, the conductive material may be at least one selected from the group consisting of _Mo2C , Mo, WC, W, TaC, Ta, SiC, carbon black, carbon nanotubes, and carbon nanofibers.

One aspect of the present invention provides an electrostatic chuck device comprising an electrostatic chuck member made of ceramic and a temperature adjustment base member made of metal bonded together via an adhesive layer, wherein the electrostatic chuck member comprises a susceptor according to one aspect of the present invention.

The present invention provides a susceptor and an electrostatic chuck device including a susceptor that can suppress changes in the contact area between the power supply terminal and the electrode pin, even if the electrode pin tilts relative to the power supply terminal due to shear stress caused by differences in the linear expansion coefficients of the mounting plate, support plate, internal electrode, etc.

FIG. 2 is a cross-sectional view showing a susceptor according to an embodiment of the present invention. 1 is a cross-sectional view showing an electrostatic chuck device according to an embodiment of the present invention. FIG. 10 is a plan view showing a first modified example of a susceptor according to an embodiment of the present invention. FIG. 10 is a plan view showing a second modified example of a susceptor according to an embodiment of the present invention. FIG. 10 is a plan view showing a third modified example of a susceptor according to an embodiment of the present invention. FIG. 10 is a plan view showing a fourth modified example of a susceptor according to an embodiment of the present invention. FIG. 1 is a cross-sectional view showing a conventional susceptor.

Embodiments of a susceptor and electrostatic chuck device according to the present invention will be described below with reference to the drawings. Note that the drawings used in the following description show enlarged views of key features for convenience, and the dimensional proportions of each component may differ from the actual dimensions. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited to them. Appropriate changes can be made without departing from the spirit of the present invention.

[Susceptor]
1 is a cross-sectional view showing a susceptor according to the present embodiment. As shown in Fig. 1, the susceptor 1 according to the present embodiment includes a pair of ceramic plates 2 and 3 containing a conductive material, an electrode 4 interposed between the pair of ceramic plates 2 and 3, and a power supply terminal 5 provided to penetrate the ceramic plate 2 so as to contact the electrode 4.
Hereinafter, the ceramic plate 2 will be referred to as the first ceramic plate 2 and the ceramic plate 3 will be referred to as the second ceramic plate 3.
1, the susceptor 1 is formed by laminating a first ceramic plate 2, an electrode 4, and a second ceramic plate 3 in this order. That is, the susceptor 1 is a bonded body in which the first ceramic plate 2 and the second ceramic plate 3 are bonded together via the electrode 4.

As shown in FIG. 1, the second ceramic plate 3 has a mounting surface 3a on which a sample (not shown) is placed. That is, the mounting surface 3a is the surface (upper surface) of the second ceramic plate 3 opposite the electrode 4.

As shown in FIG. 1, the susceptor 1 of this embodiment has a recess 6 recessed toward the mounting surface 3a, including the power supply terminal 5, on the surface (lower surface) 2a of the first ceramic plate 2 opposite the electrode 4. In the susceptor 1 of this embodiment, the recess 6 is formed only in the power supply terminal 5. The inner surface 6a (opening) of the recess 6 extends to the boundary between the first ceramic plate 2 and the power supply terminal 5. Furthermore, the cross-sectional shape of the inner surface 6a of the recess 6 in the thickness direction of the ceramic plates 2, 3 is preferably a curved or hyperbolic shape represented by at least one curvature or a quadratic function. That is, the cross-sectional shape of the inner surface 6a of the recess 6 may be a curved or hyperbolic shape represented by one or more curvatures. Specific examples of the cross-sectional shape of the inner surface 6a of the recess 6 include the arc or circular arc shape shown in FIG. 1.

The shape and size of the inner surface 6a of the recess 6 are not particularly limited, but as shown in Figure 1, they are adjusted appropriately depending on the shape and size of the tip 31A of the connection portion 31 of the electrode pin 30, which is pressed against the power supply terminal 5 for connection. The shape of the inner surface 6a of the recess 6 is, for example, shaped to follow the outer diameter 31a of the tip 31A. This ensures a sufficient contact area between the inner surface 6a of the recess 6 and the tip 31A of the electrode pin 30, and suppresses changes in this contact area, even if the electrode pin 30 is tilted relative to the power supply terminal 5.

The first ceramic plate 2 and the second ceramic plate 3 have the same shape at the overlapping surfaces.
The thicknesses of the first ceramic plate 2 and the second ceramic plate 3 are not particularly limited and may be adjusted appropriately depending on the intended use of the ceramic bonded body 1 .

The first ceramic plate 2 and the second ceramic plate 3 have the same composition or main components. The first ceramic plate 2 and the second ceramic plate 3 are made of a composite of an insulating material and a conductive material.

The insulating material contained in the first ceramic plate 2 and the second ceramic plate 3 is not particularly limited, but examples thereof include aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), yttrium oxide (Y ₂ O ₃ ), yttrium aluminum garnet (YAG), etc.

The conductive material contained in the first ceramic plate 2 and the second ceramic plate 3 is not particularly limited, but examples thereof include silicon carbide (SiC), titanium oxide (TiO ₂ ), titanium nitride (TiN), titanium carbide (TiC), carbon (C), carbon nanotubes (CNT), carbon nanofibers, rare earth oxides, and rare earth fluorides.

The material of the first ceramic plate 2 and the second ceramic plate 3 is not particularly limited as long as it has a volume resistivity of about ¹⁰ Ω·cm or more and ¹⁰ Ω·cm or less, mechanical strength, and durability against corrosive gases and their plasma. Examples of such materials include aluminum oxide (Al ₂ O ₃ ) sintered compacts, aluminum nitride (AlN) sintered compacts, and aluminum oxide (Al ₂ O ₃ )-silicon carbide (SiC) composite sintered compacts. However, from the viewpoints of dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance, aluminum oxide (Al ₂ O ₃ )-silicon carbide (SiC) composite sintered compacts are preferred.

The average primary particle size of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3 is preferably 0.5 μm or more and 3.0 μm or less, and more preferably 1.0 μm or more and 2.0 μm or less.
If the average primary particle diameter of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3 is 0.5 μm or more and 3.0 μm or less, the first ceramic plate 2 and the second ceramic plate 3 can be obtained as a dense plate with high voltage resistance and durability.

The average primary particle size of the insulating material that makes up the first ceramic plate 2 and the second ceramic plate 3 is measured as follows: A cross section of the first ceramic plate 2 and the second ceramic plate 3 cut in the thickness direction is observed using a field emission scanning electron microscope (FE-SEM) manufactured by JEOL Ltd., and the average primary particle size is determined by averaging the particle sizes of 200 particles of the insulating material using the intercept method.

The electrode 4 is used as a plasma generation electrode for generating plasma by passing high-frequency power to perform plasma processing; an electrostatic chuck electrode for generating an electric charge to fix a plate-shaped sample using electrostatic attraction; or a heater electrode for heating a plate-shaped sample by passing electricity through it. The shape of the electrode 4 (the shape when viewed from above (viewed from the thickness direction)) and size (thickness and area when viewed from above (viewed from the thickness direction)) are not particularly limited and can be adjusted appropriately depending on the application of the susceptor 1.

Electrode 4 is a composite of an insulating material and a conductive material.

The insulating material contained in electrode 4 is not particularly limited, but is preferably at least one selected from the group consisting of aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), yttrium (III) oxide (Y ₂ O ₃ ), yttrium aluminum garnet (YAG), and SmAlO _3. The insulating material contained in electrode 4 is preferably matched to the main components of first ceramic plate 2 and second ceramic plate 3.
By making the electrode 4 from a conductive material and an insulating material, the bonding strength between the first ceramic plate 2 and the second ceramic plate 3 and the mechanical strength of the electrode are increased.
The insulating material contained in the electrode 4 is aluminum oxide (Al ₂ O ₃ ), so that the electrode 4 maintains its dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance.

The conductive material contained in the electrode 4 is preferably at least one selected from the group consisting of molybdenum carbide ( _Mo2C ), molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers. When the conductive material contained in the electrode 4 is at least one selected from the group consisting of the above materials, the conductivity of the conductive layer can be ensured.

The ratio (compound ratio) of the content of insulating material to conductive material in the electrode 4 is not particularly limited and can be adjusted appropriately depending on the application of the susceptor 1.

The power supply terminal 5 supplies current to the electrode 4. The shape (shape of the power supply terminal 5 when viewed in a plan view (thickness direction)) and size (thickness and area of the power supply terminal 5 when viewed in a plan view (thickness direction)) of the power supply terminal 5 are not particularly limited and may be adjusted appropriately depending on the application of the susceptor 1.

The power supply terminal 5 is a composite of insulating and conductive materials.

The insulating material contained in the power supply terminal 5 is the same as the insulating material contained in the electrode 4 .
The conductive material contained in the power supply terminal 5 is the same as the conductive material contained in the electrode 4 .

The ratio (compounding ratio) of the content of insulating material to conductive material in the power supply terminal 5 is not particularly limited and is adjusted appropriately depending on the application of the susceptor 1. For example, the content of conductive material is preferably 45% by mass or more and 75% by mass or less, more preferably 50% by mass or more and 70% by mass or less, and even more preferably 55% by mass or more and 65% by mass or less. If the content of conductive material is 45% by mass or more and 75% by mass or less, sufficient current can be supplied to the electrode 4 and the power supply terminal can also be strong.

The susceptor 1 of this embodiment has a recess 6 on the surface opposite the mounting surface 3a, which includes the power supply terminal 5 and is recessed toward the mounting surface 3a. This prevents changes in the contact area between the power supply terminal 5 and the electrode pin 30, even if shear stress caused by differences in the linear expansion coefficients of the ceramic plates 2, 3, the electrode 4, etc. causes the electrode pin 30 to tilt relative to the power supply terminal 5. Furthermore, if the cross-sectional shape of the inner surface 6a of the recess 6 in the thickness direction of the ceramic plates 2, 3 is a curved or hyperbolic shape represented by at least one curvature or quadratic function, this further improves the effectiveness of preventing changes in the contact area between the power supply terminal 5 and the electrode pin 30, even if shear stress caused by differences in the linear expansion coefficients of the ceramic plates 2, 3, the electrode 4, etc. causes the electrode pin 30 to tilt relative to the power supply terminal 5.

In this embodiment, the first ceramic plate 2 and the second ceramic plate 3 are separate bodies, but the susceptor according to the present invention is not limited to this. The susceptor according to the present invention may also be one in which the first ceramic plate and the second ceramic plate are integrated and an electrode is provided inside the integrated structure.

[Susceptor manufacturing method]
Hereinafter, the method for manufacturing the susceptor of this embodiment will be described with reference to FIG.

An electrode-forming paste is applied to the upper surface 2 b of the first ceramic plate 2 by a coating method such as screen printing, to form a coating film (electrode coating film) that will become the electrode 4 .
The electrode forming paste is prepared by dispersing an insulating material and a conductive material that form the electrodes 4 in a solvent.
The solvent contained in the electrode forming paste is isopropyl alcohol or the like.

Next, a second ceramic plate 3 is laminated so that the underside 3b of the second ceramic plate 3 contacts the surface of the electrode coating opposite the surface that contacts the first ceramic plate 2.

Next, a through-hole 2A is formed in the second ceramic plate 3, extending from its underside 2a to the electrode 4, using, for example, a diamond drill, laser machining, electrical discharge machining, ultrasonic machining, or the like.

Next, a paste for forming a power supply terminal is applied to the through hole 2A by a coating method such as screen printing, to form a coating film (conductive coating film) that will become the power supply terminal 5.
The paste for forming the power supply terminals is prepared by dispersing an insulating material and a conductive material for forming the power supply terminals 5 in a solvent.
The solvent contained in the paste for forming the power supply terminal is isopropyl alcohol or the like.

Next, the laminate including the first ceramic plate 2, the coating film that will become the electrode 4, the coating film that will become the power supply terminal 5, and the second ceramic plate 3 is heated and pressed in the thickness direction. The atmosphere in which the laminate is heated and pressed in the thickness direction is preferably a vacuum or an inert atmosphere such as Ar, He, or _N2 .

The temperature at which the laminate is heated (heat treatment temperature) is preferably 1600°C or higher and 1900°C or lower, and more preferably 1650°C or higher and 1850°C or lower.
When the temperature to which the laminate is heated is 1600°C or higher and 1900°C or lower, the solvent contained in each coating film can be volatilized to form the electrode 4 between the first ceramic plate 2 and the second ceramic plate 3. Furthermore, the first ceramic plate 2 and the second ceramic plate 3 can be joined together via the electrode 4.

The pressure (pressure) applied to the laminate in the thickness direction is preferably 1.0 MPa or more and 50.0 MPa or less, and more preferably 5.0 MPa or more and 20.0 MPa or less.
When the pressure applied to the laminate in the thickness direction is 1.0 MPa or more and 50.0 MPa or less, the electrode 4 can be formed between the first ceramic plate 2 and the second ceramic plate 3. Furthermore, the first ceramic plate 2 and the second ceramic plate 3 can be joined and integrated via the electrode 4.

Next, a recess 6 including the power supply terminal 5 and recessed toward the mounting surface 3a is formed on the underside 2a of the first ceramic plate 2 using laser machining, electric discharge machining, ultrasonic machining, or other methods, to obtain the susceptor 1.

[Electrostatic chuck device]
An electrostatic chuck device according to one embodiment of the present invention will be described below with reference to FIG.

Fig. 2 is a cross-sectional view showing an electrostatic chuck device according to this embodiment. In Fig. 2, the same components as those in the ceramic bonded body shown in Fig. 1 are denoted by the same reference numerals, and redundant description will be omitted.
2 , the electrostatic chuck device 100 of this embodiment includes a disk-shaped electrostatic chuck member 102, a disk-shaped temperature adjustment base member 103 that adjusts the electrostatic chuck member 102 to a desired temperature, and an adhesive layer 104 that bonds and integrates the electrostatic chuck member 102 and the temperature adjustment base member 103. In the electrostatic chuck device 100 of this embodiment, the electrostatic chuck member 102 is, for example, the susceptor 1 of the above-described embodiment. Here, a case where the electrostatic chuck member 102 is the susceptor 1 will be described.
In the following description, the side of the mounting surface 111a of the mounting plate 111 will be referred to as "upper" and the side of the temperature adjusting base member 103 as "lower" to indicate the relative positions of the respective components.

[Electrostatic chuck member]
The electrostatic chuck member 102 includes a ceramic mounting plate 111 having an upper surface serving as a mounting surface 111a on which a plate-like sample such as a semiconductor wafer is placed, a support plate 112 provided on the side of the mounting plate 111 opposite the mounting surface 111a, an electrostatic attraction electrode 113 sandwiched between the mounting plate 111 and the support plate 112, an annular insulating material 114 sandwiched between the mounting plate 111 and the support plate 112 and surrounding the electrostatic attraction electrode 113, a power supply terminal 116 provided in a through hole 115 in the support plate 112 so as to be in contact with the electrostatic attraction electrode 113, and an electrode pin 118 provided in a fixing hole 117 in the temperature adjustment base member 103.
In the electrostatic chuck member 102, the mounting plate 111 corresponds to the second ceramic plate 3, the support plate 112 corresponds to the first ceramic plate 2, the electrostatic attraction electrode 113 corresponds to the electrode 4, the power supply terminal 116 corresponds to the power supply terminal 5, and the electrode pin 118 corresponds to the electrode pin 30.

[Placement plate]
The mounting surface 111a of the mounting plate 111 has a number of protrusions (not shown) for supporting a plate-shaped sample such as a semiconductor wafer. Furthermore, a circular protrusion with a square cross section may be provided around the periphery of the mounting surface 111a of the mounting plate 111 to prevent leakage of a cooling gas such as helium (He). Furthermore, a plurality of protrusions having the same height as the circular protrusion, a circular cross section, and a substantially rectangular vertical cross section may be provided in the area surrounded by the circular protrusion on the mounting surface 111a.

The thickness of the mounting plate 111 is preferably 0.3 mm or more and 3.0 mm or less, and more preferably 0.5 mm or more and 1.5 mm or less. If the thickness of the mounting plate 111 is 0.3 mm or more, it has excellent voltage resistance. On the other hand, if the thickness of the mounting plate 111 is 3.0 mm or less, the electrostatic adsorption force of the electrostatic chuck member 102 is not reduced, and the thermal conductivity between the plate-shaped sample placed on the mounting surface 111a of the mounting plate 111 and the temperature adjustment base member 103 is not reduced, making it possible to maintain the temperature of the plate-shaped sample at a desired constant temperature during processing.

[Support plate]
The support plate 112 supports the mounting plate 111 and the electrostatic attraction electrode 113 from below.

The thickness of the support plate 112 is preferably 0.3 mm or more and 3.0 mm or less, and more preferably 0.5 mm or more and 1.5 mm or less. If the thickness of the support plate 112 is 0.3 mm or more, sufficient voltage resistance can be ensured. On the other hand, if the thickness of the support plate 112 is 3.0 mm or less, the electrostatic adsorption force of the electrostatic chuck member 102 is not reduced, and the thermal conductivity between the plate-shaped sample placed on the mounting surface 111a of the mounting plate 111 and the temperature adjustment base member 103 is not reduced, making it possible to maintain the temperature of the plate-shaped sample during processing at a desired constant temperature.

[Electrostatic attraction electrode]
When a voltage is applied to the electrostatic attraction electrode 113 , an electrostatic attraction force is generated that holds the plate-shaped sample on the mounting surface 111 a of the mounting plate 111 .

The thickness of the electrostatic attraction electrode 113 is preferably 5 μm or more and 200 μm or less, and more preferably 10 μm or more and 100 μm or less. If the thickness of the electrostatic attraction electrode 113 is 5 μm or more, sufficient conductivity can be ensured. On the other hand, if the thickness of the electrostatic attraction electrode 113 is 200 μm or less, the thermal conductivity between the plate-shaped sample placed on the mounting surface 111a of the mounting plate 111 and the temperature adjustment base member 3 is not reduced, and the temperature of the plate-shaped sample during processing can be maintained at a desired constant temperature. Furthermore, plasma permeability is not reduced, allowing stable plasma generation.

[Insulation material]
The insulating material 114 surrounds the electrostatic attraction electrode 113 to protect the electrostatic attraction electrode 113 from corrosive gases and their plasma.
The mounting plate 111 and the support plate 112 are joined together by an insulating material 114 via an electrostatic attraction electrode 113 .

The insulating material 114 is provided to join the boundary between the mounting plate 111 and the support plate 112, i.e., the outer edge region other than the portion where the electrostatic attraction electrode 113 is formed. The shape of the insulating material 114 (the shape of the insulating material 114 when viewed in a plan view (viewed from the thickness direction)) is not particularly limited and is adjusted appropriately depending on the shape of the electrostatic attraction electrode 113.
In the electrostatic chuck device 100 of this embodiment, the thickness of the insulating material 114 is equal to the thickness of the electrostatic attraction electrode 113 .

The insulating material 114 is made of an insulating material.
The insulating material constituting the insulating material 114 is not particularly limited, but is preferably the same as the main component of the mounting plate 111 and the support plate 112, and examples thereof include aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), yttrium oxide (Y ₂ O ₃ ), yttrium aluminum garnet (YAG), etc. The insulating material constituting the insulating material 114 is preferably aluminum oxide (Al ₂ O ₃ ). By using aluminum oxide (Al ₂ O ₃ ) as the insulating material constituting the insulating material 114, dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance are maintained.

The average primary particle size of the insulating material that makes up the insulating material 114 is preferably 1.6 μm or more and 10.0 μm or less, and more preferably 1.6 μm or more and 6.0 μm or less.
If the average primary particle size of the insulating material constituting the insulating material 114 is 1.6 μm or more, sufficient voltage resistance can be obtained. On the other hand, if the average primary particle size of the insulating material constituting the insulating material 114 is 10.0 μm or less, workability such as grinding is good.

The method for measuring the average primary particle diameter of the insulating material that makes up the insulating material 114 is the same as the method for measuring the average primary particle diameter of the insulating material that makes up the mounting plate 111 and the support plate 112.

[Power supply terminal]
The power supply terminal 116 supplies a current to the electrostatic attraction electrode 113 .
The number, shape, etc. of the power supply terminals 116 are determined by the type of the electrostatic attraction electrode 113, that is, whether it is a monopolar type or a bipolar type.

[Electrode pin]
The electrode pin 118 supplies current to the power supply terminal 116. The electrode pin 118 has a structure similar to that of the electrode pin 30 shown in Fig. 1. The electrode pin 30 has a connection portion 31 that is pressed against the power supply terminal 5 to connect, and a spring 32 provided on the side of the connection portion 31 opposite to a tip portion 31A. The elastic force of the spring 32 presses the tip portion 31A against the power supply terminal 116, thereby connecting the power supply terminal 116 and the electrode pin 118.

[Temperature adjustment base member]
The temperature adjustment base member 103 is a thick, disk-shaped member made of at least one of metal and ceramic. The base member 103 has a structure that also serves as an internal electrode for generating plasma. A flow path 121 is formed inside the base member 103, through which a cooling medium such as water, He gas, or _N2 gas circulates.

The body of the temperature adjustment base member 103 is connected to an external high-frequency power supply 122. An electrode pin 118, whose outer periphery is surrounded by insulating material 123, is fixed in a fixing hole 117 of the temperature adjustment base member 103 via the insulating material 123. The electrode pin 118 is connected to an external DC power supply 124.

The material constituting the temperature adjusting base member 103 is not particularly limited as long as it is a metal or a composite material containing such a metal that has excellent thermal conductivity, electrical conductivity, and workability. Suitable materials for the temperature adjusting base member 3 include, for example, aluminum (Al), copper (Cu), stainless steel (SUS), and titanium (Ti).
At least the surface of the temperature adjusting base member 103 that is exposed to plasma is preferably anodized or coated with a polyimide resin. It is more preferable that the entire surface of the temperature adjusting base member 103 is anodized or coated with the resin.

By applying anodizing or resin coating to the temperature adjustment base member 103, the plasma resistance of the temperature adjustment base member 103 is improved and abnormal discharge is prevented. This improves the plasma resistance stability of the temperature adjustment base member 103 and also prevents surface scratches on the temperature adjustment base member 103.

[Adhesive layer]
The adhesive layer 104 bonds the electrostatic chuck portion 102 and the cooling base portion 103 together.

The thickness of the adhesive layer 104 is preferably 100 μm or more and 200 μm or less, and more preferably 130 μm or more and 170 μm or less.
If the thickness of the adhesive layer 104 is within the above range, it is possible to sufficiently maintain the adhesive strength between the electrostatic chuck portion 102 and the cooling base portion 103. It is also possible to sufficiently ensure the thermal conductivity between the electrostatic chuck portion 102 and the cooling base portion 103.

The adhesive layer 104 is formed of, for example, a hardened product obtained by heat-hardening a silicone-based resin composition, an acrylic resin, an epoxy resin, or the like.
Silicone-based resin compositions are more preferred because they are silicon compounds having siloxane bonds (Si—O—Si) and are resins with excellent heat resistance and elasticity.

As such a silicone-based resin composition, a silicone resin having a heat curing temperature of 70°C to 140°C is particularly preferred.
Here, if the thermosetting temperature is below 70° C., when the electrostatic chuck portion 102 and the cooling base portion 103 are joined in a facing state, the hardening does not proceed sufficiently during the joining process, resulting in poor workability, which is undesirable. On the other hand, if the thermosetting temperature is above 140° C., the difference in thermal expansion between the electrostatic chuck portion 102 and the cooling base portion 103 becomes large, which increases the stress between the electrostatic chuck portion 102 and the cooling base portion 103 and may cause peeling between them, which is undesirable.

In the electrostatic chuck device 100 of this embodiment, the electrostatic chuck member 102 is made of a susceptor 1. Therefore, even if the electrode pin 118 is tilted relative to the power supply terminal 116, a sufficient contact area can be secured between the inner surface of the recess including the power supply terminal 116 provided on the surface opposite the mounting surface 111a of the electrostatic chuck member 102 and the tip of the electrode pin 118, thereby suppressing changes in this contact area.

The manufacturing method for the electrostatic chuck device of this embodiment is described below.

An electrostatic chuck member 102 is prepared, consisting of the susceptor 1 obtained as described above.

An adhesive made of a silicone-based resin composition is applied to a predetermined region of one main surface 103a of the cooling base portion 103. The amount of adhesive applied is adjusted so that the electrostatic chuck portion 102 and the cooling base portion 103 are bonded together.
The adhesive can be applied manually using a spatula or the like, or by bar coating, screen printing, or the like.

After applying an adhesive to one main surface 103a of the cooling base portion 103, the electrostatic chuck portion 102 and the cooling base portion 103 to which the adhesive has been applied are superimposed.
Also, the electrode pins 118 are inserted and fitted into the fixing holes 117 drilled in the cooling base portion 103 .
Next, the electrostatic chuck portion 102 is pressed against the cooling base portion 103 with a predetermined pressure to bond and integrate the electrostatic chuck portion 102 and the cooling base portion 103. As a result, the electrostatic chuck portion 102 and the cooling base portion 103 are bonded and integrated via the adhesive layer 104.

As a result of the above, the electrostatic chuck unit 102 and the cooling base unit 103 are bonded together via the adhesive layer 104 to obtain the electrostatic chuck device 100 of this embodiment.

The plate-shaped sample according to this embodiment is not limited to a semiconductor wafer, but may also be, for example, a glass substrate for a flat panel display (FPD) such as a liquid crystal display (LCD), plasma display (PDP), or organic electroluminescence (EL) display. Furthermore, the electrostatic chuck device according to this embodiment can be designed to match the shape and size of the substrate.

Other Embodiments
The present invention is not limited to the above-described embodiment.

For example, the susceptors 200, 300, 400, and 500 according to the first to fourth modified examples shown in Figures 3 to 6 may be adopted. Note that in the susceptors 200, 300, 400, and 500 according to the first to fifth modified examples, the same components as those in the above embodiment are designated by the same reference numerals, and their description will be omitted, with only the differences being described.

The susceptor 200 of the first modified example shown in Figure 3 has a recess 6 on the underside 2a of the first ceramic plate 2, which includes the power supply terminal 5 and the first ceramic plate 2 and is recessed toward the mounting surface 3a. That is, the inner surface 6a of the recess 6 is formed from a central portion 6A consisting of the power supply terminal 5 and an outer edge portion 6B that follows the outer edge of the central portion 6A. As a result, even if the inclination (deviation) of the electrode pin 30 relative to the power supply terminal 5 increases, a sufficient contact area between the inner surface 6a of the recess 6 and the tip 31A of the electrode pin 30 can be ensured, and changes in this contact area can be suppressed.

The susceptor 300 of the second modified example shown in Figure 4 has a recess 6 on the underside 2a of the first ceramic plate 2, which includes the power supply terminal 5 and is recessed toward the mounting surface 3a. In this modified susceptor 300, the recess 6 is formed only in the power supply terminal 5, and the inner surface 6a (opening) of the recess 6 does not reach the boundary between the first ceramic plate 2 and the power supply terminal 5. This reduces the inclination (deviation) of the electrode pin 30 relative to the power supply terminal 5, ensuring a sufficient contact area between the inner surface 6a of the recess 6 and the tip 31A of the electrode pin 30 and suppressing changes in this contact area.

The susceptor 400 of the third modified example shown in FIG. 5 includes a power supply terminal 5 and the first ceramic plate 2 on the underside 2a of the first ceramic plate 2, and has a recess 6 recessed toward the mounting surface 3a. The susceptor 400 also has a metal layer 410 covering the inner surface 6a of the recess 6. In the susceptor 400 of this modified example, the metal layer 410 is formed along the inner surface 6a of the recess 6, and the metal layer 410 has a recess 411 recessed toward the mounting surface 3a. Furthermore, the cross-sectional shape of the inner surface 411a of the recess 411 in the thickness direction of the first ceramic plate 2 is preferably a curved or hyperbolic shape represented by at least one curvature or quadratic function.

The metal layer 410 is made of a conductive material. The conductive material that makes up the metal layer 410 is not particularly limited, but examples include Ag, Cu, In, Ti, Sn, etc., and these may be used alone or in combination.

The arithmetic mean roughness (Ra) of the surface of the metal layer 410 opposite to the inner surface 6a of the recess 6 (the inner surface 411a of the recess 411) is preferably 2 μm or more and 30 μm or less, more preferably 4 μm or more and 25 μm or less, and even more preferably 6 μm or more and 20 μm or less.
If the arithmetic mean roughness (Ra) of the inner surface 411a of the recess 411 is 2 μm or more and 30 μm or less, a sufficient current can be supplied from the power supply pin 30 to the power supply terminal 5, and the wear of the power supply terminal 5 can be reduced.

The arithmetic mean roughness (Ra) of the inner surface 411a of the recess 411 is measured using a stylus-type surface roughness tester manufactured by Tokyo Seimitsu Co., Ltd., in accordance with JIS B 0601:2013 "Geometric Product Specifications (GPS) - Surface Texture: Profile Curve Method - Terms, Definitions, and Surface Texture Parameters."

By providing the metal layer 410, the resistance due to the connection between the power supply terminal 5 and the power supply pin 30 can be reduced, improving the conductivity between them.

The susceptor 500 of the fourth modified example shown in FIG. 6 includes only the power supply terminal 5 on the underside 2a of the first ceramic plate 2, and has a recess 6 recessed toward the mounting surface 3a. Furthermore, the susceptor 400 has a metal layer 510 covering the inner surface 6a of the recess 6. In this modified susceptor 500, the metal layer 510 is formed along the inner surface 6a of the recess 6, and the metal layer 510 has a recess 511 recessed toward the mounting surface 3a. Furthermore, the cross-sectional shape of the inner surface 511a of the recess 511 in the thickness direction of the first ceramic plate 2 preferably has at least one curvature or a curved or hyperbolic shape represented by a quadratic function. The metal layer 510 is made of a conductive material. Examples of conductive materials that make up the metal layer 510 include the same conductive materials that make up the metal layer 410. Providing the metal layer 510 reduces the resistance due to the connection between the power supply terminal 5 and the power supply pin 30, improving their electrical conductivity.

The susceptor of the present invention includes a power supply terminal on the surface opposite the mounting surface, and has a recessed portion that is recessed toward the mounting surface. This prevents changes in the contact area between the power supply terminal and the electrode pin even when shear stress caused by differences in the linear expansion coefficients of the ceramic plate, electrode, etc. causes the electrode pin to tilt relative to the power supply terminal. This makes it suitable for use as an electrostatic chuck member in an electrostatic chuck device, and its usefulness is extremely high.

1 susceptor 2 ceramic plate (first ceramic plate)
3. Ceramic plate (second ceramic plate)
4 Electrode 5 Power supply terminal 6 Recess 30 Electrode pin 100 Electrostatic chuck device 102 Electrostatic chuck member 103 Temperature adjustment base member 104 Adhesive layer 111 Mounting plate 112 Support plate 113 Electrostatic attraction electrode 114 Insulating material 115 Through hole 116 Power supply terminal 117 Fixing hole 118 Electrode pin 121 Flow path 122 High frequency power supply 123 Insulating material 124 DC power supply

Claims (7)

An electrostatic chuck device comprising an electrostatic chuck member made of ceramic and a temperature adjusting base member made of metal bonded together via an adhesive layer,
the electrostatic chuck member includes an electrode provided inside a ceramic plate having a mounting surface on which a sample is placed, and a power supply terminal provided to penetrate the ceramic plate so as to contact the electrode,
a recessed portion recessed toward the placement surface on a surface opposite to the placement surface,
the power supply terminal is exposed on the opposite surface and forms at least a part of the recess;
the temperature adjusting base member has an electrode pin that is connected to the power supply terminal and supplies a current to the power supply terminal;
The electrode pin has a connection portion that is pressed against the power supply terminal to be connected, and a spring that presses the connection portion against the power supply terminal, and the electrode pin is an electrostatic chuck device that can tilt with respect to the power supply terminal . The electrostatic chuck device of claim 1, wherein the cross-sectional shape of the inner surface of the recess in the thickness direction of the ceramic plate is a curve or hyperbolic shape expressed by at least one curvature or quadratic function. The electrostatic chuck device of claim 2, having a metal layer coating the inner surface. The electrostatic chuck device of claim 3, wherein the arithmetic mean roughness (Ra) of the surface of the metal layer opposite the inner surface is 2 μm or more and 30 μm or less. An electrostatic chuck device according to any one of claims 1 to 4, wherein the electrode and the power supply terminal are a composite of an insulating material and a conductive material. 6. The electrostatic chuck device according to claim ₅ , wherein the insulating material is at least one selected from the group consisting of aluminum oxide, aluminum nitride, silicon nitride, yttrium (III) oxide, yttrium aluminum garnet, and SmAlO3. 7. The electrostatic chuck device according to claim 5, wherein the conductive material is at least one selected from the group consisting of _Mo2C , Mo, WC, W, TaC, Ta, SiC, carbon black, carbon nanotubes, and carbon nanofibers.