JP2024139668A - Electrostatic Chuck - Google Patents

Abstract

To provide an electrostatic chuck capable of inhibiting local heating in a dielectric substrate.SOLUTION: An electrostatic chuck 10 comprises: a dielectric substrate 100; electrode terminals 50 provided on a face 120 of the dielectric substrate 100; a heater 400 built into the dielectric substrate 100; a bypass layer 500B built into the dielectric substrate 100 at a position between the heater 400 and the electrode terminal 50; a plurality of first connections 610B electrically connecting the heater 400 and the bypass layer 500B; and second connections 620B electrically connecting the bypass layer 500B and the electrode terminal 50. The electrical resistance per connection of the second connections 620B is less than the electrical resistance per connection of the first connections 610.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electrostatic chuck.

For example, semiconductor manufacturing equipment such as CVD equipment and etching equipment is provided with an electrostatic chuck as a device for attracting and holding a substrate such as a silicon wafer to be processed. The electrostatic chuck comprises a dielectric substrate provided with an attraction electrode and a base plate that supports the dielectric substrate, which are joined together. When a voltage is applied to the attraction electrode, an electrostatic force is generated, and a substrate placed on the dielectric substrate is attracted and held.

A conductor layer, such as a heater for heating the dielectric substrate or an RF electrode, is embedded inside the dielectric substrate. An electrode portion (e.g., an electrode terminal) for supplying power to the conductor layer is provided on the side of the dielectric substrate opposite the mounting surface. The conductor layer and the electrode portion are electrically connected by an electric path provided inside the dielectric substrate.

As shown in the following Patent Document 1, a bypass layer (drawing section) may be provided between the conductor layer and the electrode section as part of the electrical path connecting the two. By providing a bypass layer, it is possible to increase the degree of freedom in arranging the electrode section on the dielectric substrate. In addition, the number of electrode sections can be reduced by consolidating multiple electrical paths connected to the conductor layer in the bypass layer and connecting it to the electrode section.

Patent No. 7184034

When multiple electrical paths connected to a conductor layer are consolidated in a bypass layer, the current flowing through the connection between the bypass layer and the electrode portion becomes larger than the current flowing through the connection between the conductor layer and the bypass layer. If this causes localized heat generation inside the dielectric substrate, the temperature of the substrate during processing will increase locally, which is undesirable.

The present invention was made in consideration of these problems, and its purpose is to provide an electrostatic chuck that can suppress localized heat generation in a dielectric substrate.

In order to solve the above problems, the electrostatic chuck according to the present invention includes a dielectric substrate having a mounting surface on which an object to be attracted is placed, an electrode portion provided on the dielectric substrate at a position opposite to the mounting surface, a conductor layer built into the dielectric substrate, a bypass layer built into the dielectric substrate at a position between the conductor layer and the electrode portion, a plurality of first connection portions electrically connecting between the conductor layer and the bypass layer, and a second connection portion electrically connecting between the bypass layer and the electrode portion. The electrical resistance of each of the second connection portions is smaller than the electrical resistance of each of the first connection portions.

In an electrostatic chuck configured in this way, the electrical resistance of the second connection portion, through which a relatively large current flows, is smaller than the electrical resistance of the first connection portion. This reduces the Joule heat generated in the second connection portion, making it possible to suppress localized heat generation associated with large currents.

In the electrostatic chuck according to the present invention, it is also preferable that each of the first connection portion and the second connection portion includes a plurality of via portions extending in a direction perpendicular to the mounting surface. By configuring the plurality of via portions, it becomes possible to easily adjust the electrical resistance in each of the first connection portion and the second connection portion.

In addition, in the electrostatic chuck according to the present invention, it is also preferable that the number of via portions included in the second connection portion is greater than the number of via portions included in the first connection portion. This makes it possible to easily adjust the electrical resistance of each of the first connection portion and the second connection portion by the number of via portions.

In addition, in the electrostatic chuck according to the present invention, it is also preferable that the cross-sectional area of each via portion included in the first connection portion is equal to the cross-sectional area of each via portion included in the second connection portion. This makes it possible to easily adjust the electrical resistance of each of the first connection portion and the second connection portion by simply changing the number of via portions. Furthermore, by making the cross-sectional areas of all the via portions equal, it is also possible to distribute current evenly to the multiple via portions in each of the first connection portion and the second connection portion.

In addition, in the electrostatic chuck according to the present invention, it is also preferable that the multiple via portions are arranged at equal intervals in the circumferential direction in each of the first connection portion and the second connection portion. Since the via portions, which are the locations where Joule heat is generated, are evenly distributed in the first connection portion, etc., localized heat generation can be further suppressed.

In addition, in the electrostatic chuck according to the present invention, the bypass layer includes a first bypass layer and a second bypass layer provided at a position between the first bypass layer and the electrode portion, the conductor layer and the first bypass layer are electrically connected by a first connection portion, the second bypass layer and the electrode portion are electrically connected by a second connection portion, and the electrostatic chuck further includes a plurality of third connection portions electrically connecting the first bypass layer and the second bypass layer, and it is also preferable that the electrical resistance of each of the second connection portions is smaller than the electrical resistance of each of the third connection portions.

Depending on the number of conductor layers and restrictions on the placement of the electrode parts, it may be preferable to divide the bypass layer into multiple parts. Even in such a configuration, it is possible to suppress localized heat generation associated with large currents by reducing the electrical resistance of the second connection part through which a large current flows.

In addition, in the electrostatic chuck according to the present invention, each of the second connection portion and the third connection portion preferably includes a plurality of via portions extending in a direction perpendicular to the mounting surface, and the number of via portions included in the second connection portion is greater than the number of via portions included in the third connection portion. This makes it possible to easily adjust the electrical resistance of each of the second connection portion and the third connection portion by the number of via portions.

The present invention provides an electrostatic chuck that can suppress localized heat generation in a dielectric substrate.

1 is a cross-sectional view illustrating a schematic configuration of an electrostatic chuck according to a first embodiment. 3A to 3C are diagrams illustrating examples of the arrangement of multiple heaters built into the dielectric substrate according to the first embodiment. FIG. 2 is a diagram illustrating an overall electrical path including a heater and a bypass layer in the first embodiment. 4A to 4C are cross-sectional views each showing a schematic arrangement of via portions in a first connection portion and a second connection portion in the first embodiment. 10A to 10C are cross-sectional views each showing an arrangement of via portions in a first connection portion and a second connection portion in a modified example of the first embodiment; FIG. 11 is a cross-sectional view showing a schematic view of an entire electrical path including a heater and a bypass layer in a second embodiment. 10A to 10C are cross-sectional views each showing a schematic arrangement of via portions in a first connection portion, a third connection portion, and a second connection portion in a second embodiment.

Hereinafter, this embodiment will be described with reference to the attached drawings. To facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicate descriptions will be omitted.

A first embodiment will be described. The electrostatic chuck 10 according to this embodiment is configured to attract and hold a substrate W to be processed by electrostatic force inside a semiconductor manufacturing apparatus (not shown), such as a CVD film forming apparatus. The substrate W is, for example, a silicon wafer. The electrostatic chuck 10 may also be used in apparatus other than semiconductor manufacturing apparatus.

Figure 1 shows a schematic cross-sectional view of the configuration of an electrostatic chuck 10 when it attracts and holds a substrate W. The electrostatic chuck 10 includes a dielectric substrate 100, a base plate 200, and a bonding layer 300.

The dielectric substrate 100 is a substantially disk-shaped member made of a sintered ceramic body. The dielectric substrate 100 contains, for example, high-purity aluminum oxide (Al ₂ O ₃ ), but may contain other materials. The purity, type, and additives of the ceramics in the dielectric substrate 100 can be appropriately set in consideration of the plasma resistance and other properties required of the dielectric substrate 100 in semiconductor manufacturing equipment.

The upper surface 110 of the dielectric substrate 100 in FIG. 1 is a "mounting surface" on which the substrate W, which is the object to be attracted, is placed. The lower surface 120 of the dielectric substrate 100 in FIG. 1 (i.e., the surface 120 opposite to the surface 110) is a "bonded surface" that is bonded to the base plate 200 via a bonding layer 300 described below. The viewpoint when the electrostatic chuck 10 is viewed from the surface 110 side along a direction perpendicular to the surface 110 is hereinafter also referred to as "top view."

An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is a thin, flat layer made of a metal material such as tungsten, and is arranged parallel to the surface 110. In addition to tungsten, the material of the adsorption electrode 130 may be molybdenum, platinum, palladium, or the like. When a voltage is applied to the adsorption electrode 130 from the outside via a power supply path (not shown), an electrostatic force is generated between the surface 110 and the substrate W, thereby adsorbing and holding the substrate W. Two adsorption electrodes 130 may be provided as so-called "bipolar" electrodes as in this embodiment, or only one may be provided as a so-called "monopolar" electrode.

A space SP is formed between the dielectric substrate 100 and the substrate W. When processing such as film formation is performed in the semiconductor manufacturing equipment, helium gas for temperature adjustment is supplied to the space SP from the outside through a gas hole (not shown) formed in the dielectric substrate 100. By interposing helium gas between the dielectric substrate 100 and the substrate W, the thermal resistance between them is adjusted, thereby maintaining the temperature of the substrate W at an appropriate temperature. The temperature adjustment gas supplied to the space SP may be a type of gas other than helium.

A seal ring 111 and dots 112 are provided on the surface 110, which is the adsorption surface, and a space SP is formed around these.

The seal ring 111 is a wall that divides the space SP at the outermost position. The upper end of each seal ring 111 forms part of the surface 110 and abuts against the substrate W. Note that multiple seal rings 111 may be provided to divide the space SP. With this configuration, it is possible to individually adjust the helium gas pressure in each space SP and make the surface temperature distribution of the substrate W during processing more uniform.

The portion marked with the reference symbol "116" in FIG. 1 and other figures is the bottom surface of the space SP. Hereinafter, this portion will also be referred to as the "bottom surface 116." The seal ring 111, together with the dots 112 described below, is formed as a result of digging down a portion of the surface 110 to the position of the bottom surface 116. The bottom surface 116 may have grooves formed therein to quickly diffuse the helium gas within the space SP.

The dots 112 are circular protrusions that protrude from the bottom surface 116. A plurality of dots 112 are provided, and are distributed approximately evenly on the adsorption surface of the dielectric substrate 100. The upper end of each dot 112 forms part of the surface 110 and abuts against the substrate W. By providing a plurality of such dots 112, deflection of the substrate W is suppressed.

The heater 400 is built into the dielectric substrate 100. The heater 400 is an electric heater that generates heat when power is supplied from the outside. The heater 400 is a thin, flat layer made of a metal material such as tungsten, and is embedded in a position between the chucking electrode 130 and the surface 120. The material of the heater 400 is not limited to tungsten, and other materials may be used. The heater 400 is routed in a linear pattern parallel to the surface 110. The specific shape of the heater 400 will be described later. The heater 400 corresponds to the "conductor layer" in this embodiment.

Multiple heaters 400 are provided, and are arranged at different positions when viewed from above. This makes it possible to individually adjust the heat generation amount of each heater 400 and suppress variations in the in-plane temperature distribution of the substrate W. Each heater 400 has the same distance from the surface 110 (i.e., the embedded depth).

The dielectric substrate 100 is provided with an electrical path for supplying power from the outside to each heater 400. The electrical path includes a bypass layer 500, a first connection portion 610, a second connection portion 620, and an electrode terminal 50.

The bypass layer 500 is a thin, flat layer made of a metal material such as tungsten, and is embedded in the dielectric substrate 100 at a position between the heater 400 and the surface 120. The material of the bypass layer 500 is not limited to tungsten, and other materials may be used. In order to enable individual power supply to each heater 400, multiple bypass layers 500 are provided and are arranged at different positions from each other when viewed from above. In this embodiment, the bypass layer 500 is provided on the dielectric substrate 100, thereby increasing the freedom of arrangement of the electrode terminals 50 on the surface 120. The specific configuration of the bypass layer 500 will be described later.

The first connection portion 610 is a portion that electrically connects the heater 400, which is a conductor layer, and the bypass layer 500. As will be described later, in this embodiment, multiple first connection portions 610 are connected to one bypass layer 500.

Each first connection portion 610 includes a plurality of via portions 611 (not shown in FIG. 1, see FIG. 4) arranged in a circular pattern when viewed from above. Each via portion 611 is generally cylindrical and extends in a direction perpendicular to the surface 110. The via portion 611 is formed by filling the inside of a hole (via) formed to extend in a direction perpendicular to the surface 110 with a conductive material such as tungsten. The first connection portion 610 includes a plurality of via portions 611, which each connect the heater 400 to the bypass layer 500.

The second connection portion 620 is a portion that electrically connects the bypass layer 500 and the electrode terminal 50 described below. As described later, in this embodiment, one second connection portion 620 is connected to one bypass layer 500.

Each second connection portion 620 includes a plurality of via portions 621 (not shown in FIG. 1, see FIG. 4) arranged in a circular arrangement in a top view. Like the via portion 611 described above, each via portion 621 is generally cylindrical and extends in a direction perpendicular to the surface 110. The via portion 621 is formed by filling the inside of a hole (via) formed to extend in a direction perpendicular to the surface 110 with a conductive material such as tungsten. In the second connection portion 620, each of the plurality of via portions 621 included therein connects the bypass layer 500 and the electrode terminal 50.

The electrode terminal 50 is a metal terminal embedded in the surface 120 as a part that receives power supplied from the outside to the heater 400. A plurality of electrode terminals 50 are provided on the surface 120, and one end of the power supply path 13 is connected to each electrode terminal 50. The power supply path 13 is a conductive metal member (e.g., a bus bar) and is drawn out to the outside through a through hole (not shown) provided in the base plate 200. For example, a cylindrical insulating member may be provided between the inner surface of the through hole and the power supply path 13. The electrode terminal 50 is a part that receives power from the outside at a position on the dielectric substrate 100 opposite the surface 110. The electrode terminal 50 corresponds to the "electrode portion" in this embodiment.

A brazing material for fixing the electrode terminal 50 may be interposed between the electrode terminal 50 and the second connection part 620. Alternatively, instead of the electrode terminal 50, for example, a thin metal plate connected to the second connection part 620 may be provided, and a rod-shaped pin inserted from the outside may be abutted against the metal plate. In this case, the metal plate corresponds to the "electrode part".

The electrostatic chuck 10 is provided with a large number of bypass layers 500, first connection parts 610, second connection parts 620, and electrode terminals 50 that constitute the electrical paths described above. However, only some of these are shown in schematic form in FIG. 1, and the rest are not shown.

The base plate 200 is a substantially disk-shaped member that is bonded to the surface 120 of the dielectric substrate 100 in order to support the dielectric substrate 100. The base plate 200 is formed of a metal such as aluminum. The surface 210 of the base plate 200, which is on the upper side in FIG. 1, is a "bonded surface" that is bonded to the dielectric substrate 100 via a bonding layer 300. The surface of the base plate 200, including the surface 210, may be covered with an insulating film such as an alumina sprayed film.

The bonding layer 300 is a layer provided between the dielectric substrate 100 and the base plate 200, and bonds the two together. The bonding layer 300 is made by hardening an adhesive made of an insulating material. For example, a silicone-based adhesive can be used as such an adhesive.

A coolant flow path 250 for flowing a coolant is formed inside the base plate 200. When a process such as film formation is performed in the semiconductor manufacturing device, a coolant is supplied to the coolant flow path 250 from the outside, thereby cooling the base plate 200. Heat generated in the substrate W during processing is transferred to the coolant via the helium gas in the space SP, the dielectric substrate 100, and the base plate 200, and is discharged to the outside together with the coolant.

The configuration of the heater 400 will be described. In FIG. 2, the dielectric substrate 100 is illustrated as a schematic top view. Each area HA shown in the figure represents an area in which a single heater 400 is routed. Each of the multiple heaters 400 is routed individually within its respective area HA. In the example of FIG. 2, a total of 48 heaters 400 are provided.

Figure 3 shows a schematic perspective view of two areas HA, two heaters 400 arranged in the areas, and a bypass layer 500 connected to the heaters 400. One of the two areas HA shown in Figure 3 is also referred to as "area HA1" below. The other area HA is also referred to as "area HA2" below.

As shown in FIG. 3, in each region HA, one linear heater 400 is routed along a path that passes through the entire range evenly. A circular pad portion 401 is formed at one end of the heater 400, and a circular pad portion 402 is formed at the other end. Both pad portions 401 and 402 are portions to which the first connection portion 610 is connected, and are provided so as to encompass the entire first connection portion 610 when viewed from above. The first connection portion 610 connected to the pad portion 401 is also referred to as the "first connection portion 610A" below. The first connection portion 610 connected to the pad portion 402 is also referred to as the "first connection portion 610B" below.

In the example of FIG. 3, three bypass layers 500 are arranged below areas HA1 and HA2. Of these, the bypass layer 500 arranged so as to overlap only one of areas HA1 or HA2 in top view is also referred to as "bypass layer 500A" below. Also, the bypass layer 500 arranged so as to straddle both areas HA1 and HA2 in top view is also referred to as "bypass layer 500B" below. Two bypass layers 500A and one bypass layer 500B are depicted in FIG. 3.

The upper end of the first connection portion 610A is connected to the pad portion 401 of each heater 400. The lower end of the first connection portion 610A is connected to the bypass layer 500A. The bypass layer 500A connected to the heater 400 in area HA1 and the bypass layer 500A connected to the heater 400 in area HA2 are separated from each other.

The upper end of the first connection portion 610B is connected to the pad portion 402 of each heater 400. The lower ends of the two first connection portions 610B are both connected to the bypass layer 500B.

As described above, the pad portion 401 of each heater 400 is connected to the bypass layer 500A provided individually for each heater 400 via the first connection portion 610A. On the other hand, the pad portion 402 of each heater 400 is connected to the common bypass layer 500B via the first connection portion 610B.

An electrode terminal 50 is connected to each of the bypass layers 500A and 500B via a second connection portion 620. The second connection portion 620 whose upper end is connected to the bypass layer 500A is also referred to as the "second connection portion 620A" below. The second connection portion 620 whose upper end is connected to the bypass layer 500B is also referred to as the "second connection portion 620B" below.

The electrode terminal 50 connected to the second connection part 620A is connected to a DC power source PS via the power supply path 13. On the other hand, the electrode terminal 50 connected to the second connection part 620B is grounded via the power supply path 13.

In this embodiment, power is supplied individually to one end of each of the multiple heaters 400 from the DC power source PS. Meanwhile, the other end of each of the multiple heaters 400 is grounded via a common bypass layer 500B. The same applies to the other heaters 400 not shown in FIG. 3.

The number of heaters 400 connected to a common bypass layer 500B (which can also be said to be the number of first connection parts 610B) may be three or more. The number of second connection parts 620B connected to the bypass layer 500B may be two or more. In either case, the number of second connection parts 620B connected to the bypass layer 500B only needs to be less than the number of first connection parts 610B connected to the same bypass layer 500B. In the bypass layer 500B, current flows in from multiple first connection parts 610B and is collected, and then the current flows into the second connection parts 620B, which are fewer in number.

In such a configuration, the current passing through the second connection portion 620B is greater than the current passing through the first connection portion 610B. As a result, there is a possibility that a large amount of Joule heat will be generated locally at the position of the second connection portion 620B on the dielectric substrate 100, which may result in a localized increase in the temperature of the substrate W during processing.

Therefore, in the electrostatic chuck 10 according to this embodiment, the electrical resistance of each of the second connection parts 620B is made smaller than the electrical resistance of each of the first connection parts 610B, thereby solving the above problem. This reduces the Joule heat generated in the second connection parts 620B, making it possible to suppress localized heat generation associated with a large current.

Figure 4(A) shows a cross section of one first connection portion 610B taken along a plane parallel to face 110. In this embodiment, one first connection portion 610B includes a total of four via portions 611, which are arranged at equal intervals along the circumferential direction (i.e., along the dotted circle in Figure 4(A)). The cross-sectional shape of each via portion 611 is approximately circular, and the cross-sectional areas are approximately equal to each other.

Figure 4(B) shows a cross section of one second connection portion 620B cut along a plane parallel to face 110. In this embodiment, one second connection portion 620B includes a total of six via portions 621, which are arranged at equal intervals along the circumferential direction (i.e., along the dotted circle in Figure 4(B)). The cross-sectional shape of each via portion 621 is approximately circular, and the cross-sectional areas are approximately equal to each other. The cross-sectional area of the via portion 621 is also equal to the cross-sectional area of the via portion 611.

In this manner, in this embodiment, the number of via portions 621 included in one second connection portion 620B is greater than the number of via portions 611 included in one first connection portion 610B. As a result, the electrical resistance of each second connection portion 620B is smaller than the electrical resistance of each first connection portion 610B.

By configuring in this way, it is possible to easily adjust the electrical resistance of each of the first connection portion 610B and the second connection portion 620B by simply changing the number of via portions 611, 621. In addition, by making the cross-sectional areas of all the via portions 611, 621 equal, it is also possible to distribute current evenly to the multiple via portions 611 (or via portions 621) in each of the first connection portion 610B and the second connection portion 620B. The fact that the electrical resistance of the second connection portion 620B, etc. can be easily adjusted as described above can be said to be a result of the second connection portion 620B, etc. being configured with multiple via portions 621, etc.

As described above, in this embodiment, in each of the first connection portion 610B and the second connection portion 620B, the multiple via portions 611 (or via portions 621) are arranged so as to be aligned at equal intervals in the circumferential direction. In the first connection portion 610B, etc., the via portions 611, etc., which are the locations where Joule heat is generated, are evenly distributed and arranged, so that localized heat generation can be further suppressed.

As shown in the modified example in FIG. 5, the electrical resistance of each of the first connection portion 610B and the second connection portion 620B may be adjusted by the cross-sectional area of each of the via portions 611, etc., rather than the number of the via portions 611, etc. In this modified example, the number of the via portions 611 included in the first connection portion 610B and the number of the via portions 621 included in the second connection portion 620B are equal to each other. On the other hand, the cross-sectional area of each of the via portions 621 included in the second connection portion 620B is larger than the cross-sectional area of each of the via portions 611 included in the first connection portion 610B. As a result, the electrical resistance of each of the second connection portions 620B is smaller than the electrical resistance of each of the first connection portions 610B. Even with such a configuration, the same effect as that described above is achieved.

The second embodiment will be described. Below, differences from the first embodiment will be mainly described, and descriptions of commonalities with the first embodiment will be omitted as appropriate.

Figure 6 shows a schematic cross-sectional view of the heater 400 built into the dielectric substrate 100 of the electrostatic chuck 10 according to this embodiment, and the configuration of the electrical path connected thereto. As shown in the figure, the dielectric substrate 100 of this embodiment is provided with two bypass layers 500. Of these, the bypass layer 500 provided on the heater 400 side is also referred to as the "first bypass layer 510" below. The bypass layer 500 provided at a position between the first bypass layer 510 and the electrode terminal 50 is also referred to as the "second bypass layer 520" below.

The heater 400, which is a conductor layer, and the first bypass layer 510 are electrically connected by a first connection portion 610B. The first bypass layer 510 and the second bypass layer 520 are electrically connected by a third connection portion 630B. The second bypass layer 520 and the electrode terminal 50 are electrically connected by a second connection portion 620B.

In this embodiment, the number of first bypass layers 510 is greater than the number of second bypass layers 520. The number of first connection parts 610B connected to one first bypass layer 510 is greater than the number of third connection parts 630B connected to the same first bypass layer 510. Also, the number of third connection parts 630B connected to one second bypass layer 520 is greater than the number of second connection parts 620B connected to the same second bypass layer 520. In such a configuration, currents from multiple heaters 400 are aggregated in the first bypass layer 510, and currents from multiple first bypass layers 510 are further aggregated in the second bypass layer 520. The current then flows to the electrode terminal 50.

As a result, the current passing through the third connection portion 630B is greater than the current passing through the first connection portion 610B. Also, the current passing through the second connection portion 620B is even greater than the current passing through the third connection portion 630B.

Therefore, in this embodiment, the electrical resistance of each of the third connection parts 630B is set to be smaller than the electrical resistance of each of the first connection parts 610B. Also, the electrical resistance of each of the second connection parts 620B is set to be smaller than the electrical resistance of each of the third connection parts 630B. This reduces the Joule heat generated in the third connection parts 630B, etc., making it possible to suppress localized heat generation associated with large currents.

The electrical resistance of each of the first connection portion 610B, the second connection portion 620B, and the third connection portion 630B can be adjusted as appropriate using a configuration similar to that described in the first embodiment, etc.

Figure 7(A) shows a cross section of one first connection portion 610B when cut along a plane parallel to face 110. Figure 7(B) shows a cross section of one third connection portion 630B when cut along a plane parallel to face 110. Figure 7(C) shows a cross section of one second connection portion 620B when cut along a plane parallel to face 110.

In this embodiment, as shown in FIG. 7(A), one first connection portion 610B includes a total of four via portions 611, which are arranged at equal intervals along the circumferential direction (i.e., along the dotted circle in FIG. 7(A)). The cross-sectional shape of each via portion 611 is approximately circular, and the cross-sectional areas are approximately equal to each other.

In this embodiment, as shown in FIG. 7(B), one third connection portion 630B includes a total of five via portions 631, which are arranged at equal intervals along the circumferential direction (i.e., along the dotted circle in FIG. 7(B)). The cross-sectional shape of each via portion 631 is approximately circular, and the cross-sectional areas are approximately equal to each other. The cross-sectional area of the via portion 631 is also equal to the cross-sectional area of the via portion 611.

In this embodiment, as shown in FIG. 7(C), one second connection portion 620B includes a total of six via portions 621, which are arranged at equal intervals along the circumferential direction (i.e., along the dotted circle in FIG. 7(B)). The cross-sectional shape of each via portion 621 is approximately circular, and the cross-sectional areas are approximately equal to each other. The cross-sectional area of the via portion 621 is also equal to the cross-sectional area of the via portion 611.

In this way, each connection part is formed of multiple via parts, and the number of via parts 631 included in the third connection part 630B can be made greater than the number of via parts 611 included in the first connection part 610B located above it. Also, the number of via parts 621 included in the second connection part 620B can be made even greater than the number of via parts 631 included in the third connection part 630B located above it.

Alternatively, the electrical resistance of each of the first connection portion 610B, the second connection portion 620B, and the third connection portion 630B may be adjusted by varying the cross-sectional area of the via portion 611, etc., as in the modified example of FIG. 5.

In this embodiment, the number of bypass layers 500 is two, but the number of bypass layers 500 may be three or more. Even in this case, the bypass layers 500 are connected with connecting parts, and the electrical resistance of each connecting part can be adjusted according to the magnitude of the aggregated current flowing.

The "conductor layer" that receives power through the bypass layer 500 may be the heater 400 as in this embodiment, but it may also be a layer provided for another purpose. For example, the conductor layer may be an RF electrode, an adsorption electrode 130, etc.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of each of the above-mentioned specific examples can be combined in different ways as appropriate, as long as no technical contradictions arise.

W: Substrate 10: Electrostatic chuck 50: Electrode terminal 100: Dielectric substrate 110, 120: Surface 400: Heater 500, 500A, 500B: Bypass layer 510: First bypass layer 520: Second bypass layer 610, 610A, 610B: First connection portion 611: Via portion 620, 620A, 620B: Second connection portion 621: Via portion 630B: Third connection portion 631: Via portion

Claims (7)

a dielectric substrate having a mounting surface on which an object to be attached is placed;
an electrode portion provided on the dielectric substrate at a position opposite to the mounting surface;
A conductor layer embedded in the dielectric substrate;
a bypass layer embedded in the dielectric substrate at a position between the conductor layer and the electrode portion;
a plurality of first connection portions electrically connecting the conductor layer and the bypass layer;
a second connection portion that electrically connects the bypass layer and the electrode portion,
an electrical resistance of each of the second connection portions being smaller than an electrical resistance of each of the first connection portions; The electrostatic chuck according to claim 1, characterized in that each of the first connection portion and the second connection portion includes a plurality of via portions extending in a direction perpendicular to the mounting surface. The electrostatic chuck according to claim 2, characterized in that the number of the vias included in the second connection part is greater than the number of the vias included in the first connection part. The electrostatic chuck of claim 3, characterized in that the cross-sectional area of each of the via portions included in the first connection portion and the cross-sectional area of each of the via portions included in the second connection portion are equal to each other. The electrostatic chuck according to claim 2, characterized in that in each of the first connection portion and the second connection portion, the multiple via portions are arranged at equal intervals in the circumferential direction. The bypass layer comprises:
A first bypass layer;
a second bypass layer provided at a position between the first bypass layer and the electrode portion,
the conductor layer and the first bypass layer are electrically connected to each other by the first connection portion,
the second bypass layer and the electrode portion are electrically connected by the second connection portion,
a plurality of third connection parts electrically connecting the first bypass layer and the second bypass layer;
2. The electrostatic chuck according to claim 1, wherein an electrical resistance per one of the second connection portions is smaller than an electrical resistance per one of the third connection portions. each of the second connection portion and the third connection portion includes a plurality of via portions extending along a direction perpendicular to the mounting surface;
The electrostatic chuck according to claim 6 , wherein the number of the via portions included in the second connection portion is greater than the number of the via portions included in the third connection portion.

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