TWI834307B - Lower electrode assembly, plasma processing device and assembly method thereof - Google Patents

Abstract

The invention discloses a lower electrode assembly, a plasma processing device and an assembly method thereof. The lower electrode assembly includes an electrostatic chuck with a first bearing surface located in the middle and a second bearing surface surrounding the middle. The second bearing surface is The height of the bearing surface is lower than the height of the first bearing surface; an edge ring assembly is arranged around the middle part of the electrostatic chuck above the second bearing surface, and has a gap between it and the middle part of the electrostatic chuck. ; And an isolation layer, arranged around the middle of the electrostatic chuck, and located between the lower surface of the edge ring assembly and the second bearing surface; wherein the isolation layer is a plastic insulating material. The invention can effectively avoid arc generation in the gap between the electrostatic chuck and the edge ring assembly, thereby avoiding damage to the lower electrode assembly and scrapping of the substrate.

Description

Lower electrode assembly, plasma processing device and assembly method thereof

The invention relates to the technical field of semiconductor equipment, and in particular to a lower electrode assembly, a plasma processing device and an assembly method thereof.

Micromachining of semiconductor substrates or substrates is a well-known technology that can be used to manufacture semiconductors, flat panel displays, light emitting diodes (LEDs), solar cells, etc. An important step in micromachining manufacturing is the plasma treatment process step, which is performed inside a reaction chamber into which process gases are input. An RF source is inductively and/or capacitively coupled into the interior of the reaction chamber to excite the process gases to form and maintain a plasma. Inside the reaction chamber, the exposed substrate is supported by the lower electrode assembly and fixed in a fixed position through a certain clamping force to ensure the safety of the substrate during the manufacturing process and a high processing yield.

The lower electrode assembly not only includes an electrostatic chuck and an edge ring assembly arranged around the middle of the electrostatic chuck. The edge ring assembly generally includes a focus ring and a dielectric ring. The focus ring is generally made of conductive material (for example, Si, C or SiC) or non-electrostatic chuck. Conductive material (for example, Al ₂ O ₃ ), the dielectric ring is generally a ceramic material.

The material in the middle part of the electrostatic chuck is generally aluminum, and its thermal expansion coefficient is quite different from that of the edge ring component. In order to ensure that the electrostatic chuck works within a wide temperature range, a certain gap must be set between the edge ring assembly and the electrostatic chuck to accommodate the thermal expansion and contraction of the electrostatic chuck.

As the processing precision of the substrate becomes higher and higher, the RF power applied to the chamber becomes larger and larger, and a higher voltage is formed between the substrate W and the lower electrode assembly, which easily causes the electrostatic chuck to form a gap between the middle part and the edge ring of the electrostatic chuck. Arcs are generated in the gaps between components, causing damage to the lower electrode components and scrapping of the substrate.

In order to solve or partially solve the problems existing in the related technology, the present invention provides a lower electrode assembly, a plasma processing device and an assembly method thereof, which can effectively avoid arc generation in the gap between the electrostatic chuck and the edge ring assembly, thereby preventing Damage to the lower electrode assembly and scrapping of the substrate.

A first aspect of the present invention provides a lower electrode assembly, including: An electrostatic chuck has a first bearing surface located in its middle and a second bearing surface surrounding its middle, the height of the second bearing surface being lower than the height of the first bearing surface; an edge ring assembly, surrounding the middle part of the electrostatic chuck and disposed above the second bearing surface, with a gap between it and the middle part of the electrostatic chuck; and An isolation layer is provided around the middle part of the electrostatic chuck and is located between the lower surface of the edge ring assembly and the second bearing surface; Wherein, the isolation layer is made of plastic insulating material.

Preferably, the isolation layer is at least partially located within the gap.

Preferably, the isolation layer is made of flexible material.

Preferably, the isolation layer is made of silicone.

Preferably, the inner side of the isolation layer is in contact with the outer side wall of the middle part of the electrostatic chuck.

Preferably, the isolation layer is a ring-shaped structure; the ring width of the isolation layer is at least three times the width of the gap.

Preferably, the ring width of the isolation layer is greater than or equal to 1.5 mm.

Preferably, the middle outer wall of the electrostatic chuck has a weld; and the inner side of the isolation layer covers the weld on the electrostatic chuck.

Preferably, the second bearing surface of the electrostatic chuck has a screw hole and a screw installed in the screw hole; the isolation layer covers the screw hole and/or the screw.

Preferably, the lower surface of the edge ring component is provided with an inner annular step; the inner annular step matches the isolation layer.

Preferably, the upper surface of the isolation layer is in contact with the lower surface of the edge ring component; the lower surface of the isolation layer is in contact with the second bearing surface of the electrostatic chuck.

Preferably, the surface of the electrostatic chuck is coated with a protective layer.

Preferably, the edge ring assembly includes an insertion ring in contact with the isolation layer and a focus ring located above the insertion ring; an isolation ring is provided between the inner wall of the focus ring and the electrostatic chuck.

Preferably, the isolation layer has a split structure.

On the other hand, the present invention also provides a plasma processing device, including a chamber and a lower electrode assembly as described above, the lower electrode assembly being disposed in the chamber.

In yet another aspect, the present invention also provides a method of assembling a lower electrode assembly. The lower electrode assembly includes an electrostatic chuck. The electrostatic chuck has a first bearing surface located in its middle and a second bearing surface surrounding its middle. The height of the second bearing surface is lower than the height of the first bearing surface; the method includes the following steps: Place an isolation layer on the second bearing surface; Place the edge ring assembly on the isolation layer, with a gap between the edge ring assembly and the electrostatic chuck; and Press down on the edge ring assembly so that the edge ring assembly squeezes the isolation layer; Wherein, the isolation layer is made of plastic insulating material.

Preferably, when the edge ring assembly squeezes the isolation layer, the isolation layer deforms and moves upward along the gap.

Preferably, the middle outer wall of the electrostatic chuck has a weld; when the isolation layer deforms and moves upward along the gap to cover the weld, stop pressing down on the edge ring assembly.

Preferably, the isolation layer has a split structure and includes multiple split isolation layers; placing the isolation layer on the second bearing surface specifically includes: A plurality of split-type isolation layers are placed on the second bearing surface respectively, and the plurality of split-type isolation layers form an annular structure.

Preferably, the second bearing surface of the electrostatic chuck has a screw hole and a screw installed in the screw hole; while placing the isolation layer on the second bearing surface, the isolation layer covers the screw. holes and/or the screws.

The technical solutions provided by the present invention can include the following beneficial effects: The invention can effectively avoid arc generation in the gap between the electrostatic chuck and the edge ring assembly, thereby avoiding damage to the lower electrode assembly and scrapping of the substrate.

It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the present invention.

Embodiments of the invention will be described in more detail below with reference to the accompanying drawings. Although embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art to which this invention belongs.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this disclosure and the appended claims, the singular forms "a," "the" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms "first", "second", "third", etc. may be used in the present invention to describe various information, the information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of the present invention, the first information may also be called second information, and similarly, the second information may also be called first information. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more than two, unless otherwise explicitly and specifically limited.

The existing lower electrode assembly includes an electrostatic chuck and an edge ring assembly, and the thermal expansion coefficients of the two are quite different; in order to ensure that the electrostatic chuck can work normally within a wide temperature range, a certain gap needs to be set between the electrostatic chuck and the edge ring assembly; In addition, when the lower electrode assembly is working, a certain pressure difference will occur between the substrate carried on the electrostatic chuck and the metal exposure or turning point on the electrostatic chuck, resulting in an extremely high voltage in the gap between the electrostatic chuck and the edge ring assembly. Easy to generate arc.

Specifically, the electrostatic chuck is coated with a coating, and the coating has certain defects at the metal exposure and turning points of the electrostatic chuck, resulting in easy contact between the substrate carried on the electrostatic chuck and the metal exposure or turning points on the electrostatic chuck. An arc occurs. Among them, the exposed metal parts of the electrostatic chuck mainly refer to the screw holes/screws and welds on it.

The arc generated in the gap between the electrostatic chuck and the edge ring assembly has a complete arc path, and the gap between the electrostatic chuck and the edge ring assembly is located on the arc path; and this embodiment is intended to isolate the electrostatic chuck and the edge ring. The arc path between components, thereby avoiding arcing in the gap between the electrostatic chuck and edge ring components, is explained in detail below.

Referring to FIG. 1 , this embodiment provides a lower electrode assembly 100 . The lower electrode assembly 100 includes: an electrostatic chuck 101 , an edge ring assembly 102 and an isolation layer 103 . The electrostatic chuck 101 has a first bearing surface 1011 located in the middle and a second bearing surface 1012 surrounding the middle. The first bearing surface 1011 is used to bear the substrate W, and the height of the second bearing surface 1012 is lower than the first bearing surface 1011 the height of. The isolation layer 103 is made of insulating material and is in close contact with the lower surface of the edge ring component 102 and the second bearing surface 1012 of the electrostatic chuck 101, which can block the arc path between the electrostatic chuck 101 and the edge ring component 102, thereby preventing the electrostatic chuck from forming. An arc is generated in the gap 104 between the edge ring assembly 101 and the edge ring assembly 102 .

Specifically, the edge ring assembly 102 includes an insertion ring 1022 in contact with the isolation layer 103 and a focus ring 1021 located above the insertion ring 1022; the edge ring assembly 102 surrounds the middle part of the electrostatic chuck 101 and is disposed above the second bearing surface 1012 and with A gap 104 is provided between the middle parts of the electrostatic chuck 101; the gap 104 is used to accommodate thermal expansion between different materials during the manufacturing process. The isolation layer 103 is provided around the middle part of the electrostatic chuck 101 and is located between the lower surface of the edge ring assembly 102 and the second between the bearing surfaces 1012.

In this embodiment, the isolation layer 103 is made of plastic insulating material. Compared with other materials, the isolation layer 103 of plastic insulating material can more effectively block the arc path between the middle part of the electrostatic chuck 101 and the edge ring assembly 102, thereby more effectively preventing the arc path between the middle part of the electrostatic chuck 101 and the edge ring assembly 102. An arc occurs in the gap 104 between.

In this embodiment, part or all of the isolation layer 103 is located in the gap 104 between the middle part of the electrostatic chuck 101 and the edge ring assembly 102 . Compared with the isolation layer completely located under the edge ring assembly, the isolation layer 103 partially or completely located in the gap 104 will extend upward along the gap 104 more after being squeezed by the lower surface of the edge ring assembly 102, so that the isolation layer The volume of 103 located in the gap 104 increases, thereby enabling the isolation layer 103 to more effectively block the arc path between the electrostatic chuck 101 and the edge ring assembly 102 .

It should be pointed out that the part of the isolation layer 103 located in the gap 104 may be originally located in the gap 104, or may be deformed into the gap 104 after the isolation layer 103 is squeezed by the edge ring assembly 102. The examples do not specifically limit this.

In this embodiment, the isolation layer 103 is made of flexible material. Preferably, the isolation layer 103 is made of silicone.

In this embodiment, the inner side 1031 of the isolation layer 103 is in contact with the middle outer wall of the electrostatic chuck 101 , so that the isolation layer 103 more fully covers the bottom of the gap 104 and the middle outer wall of the electrostatic chuck 101 and the second bearing surface 1012 Connected turning point 1013.

In this embodiment, the isolation layer 103 has a ring-shaped structure; the ring width d of the isolation layer 103 is at least three times the width of the gap 104 . Preferably, the ring width d of the isolation layer 103 is greater than or equal to 1.5 mm. The isolation layer 103 with the ring width d can ensure the isolation effect of the arc path when the material used is relatively small.

In this embodiment, the middle outer wall of the electrostatic chuck 101 has a weld; the inner side 1031 of the isolation layer 103 covers the weld on the electrostatic chuck 101 to avoid arc occurrence at the weld.

In this embodiment, the second bearing surface 1012 of the electrostatic chuck 101 has screw holes and screws installed in the screw holes; the isolation layer 103 covers the screw holes and/or screws to avoid arcing at the screw holes and/or screws.

It should be noted that “plasticity” in this embodiment refers to the property of the isolation layer 103 to deform into a shape matching the lower surface of the edge ring component 102 after being squeezed by the edge ring component 102 . Based on this property, the isolation layer 103 can more fully cover the screw holes/screws, welds and turning points 1013 on the electrostatic chuck 101, and be more closely connected with the lower surface of the edge ring assembly 102 and the second bearing surface 1012 of the electrostatic chuck 101. to effectively block the arc path between the electrostatic chuck 101 and the edge ring assembly 102 .

In this embodiment, the surface of the electrostatic chuck 101 is coated with a protective layer 105 . The protective layer 105 is made of plasma corrosion-resistant material, which can increase the breakdown voltage of the electrostatic chuck 101 and prevent arcs from occurring in the gap 104 .

Preferably, the plasma corrosion resistant material of the protective layer 105 is aluminum oxide material or yttrium oxide material.

In this embodiment, the isolation layer 103 has a split structure. After assembly, it forms an annular structure that can be placed around the electrostatic chuck 101 to facilitate transportation and assembly.

Referring to FIG. 3 , in other embodiments, the lower surface of the edge ring component 202 is provided with an inner annular step 2023 that matches the isolation layer 203 . Because the isolation layer 203 will become thin after being extruded, an inner annular step 2023 is provided on the lower surface of the edge ring assembly 202 to ensure the minimum thickness of the isolation layer 203 after being extruded, thereby ensuring the insulation of the isolation layer 203 and Arc blocking performance.

It should be noted that this embodiment does not specifically limit the shape of the inner annular step 2023, and only uses the shape shown in FIG. 3 for illustrative description.

Referring to FIG. 4 , in other embodiments, an isolation ring 306 is provided between the inner side wall of the focus ring 3021 and/or the insertion ring 3022 in the edge ring assembly 302 and the middle part of the electrostatic chuck 301 . The isolation ring 306 and the isolation layer 303 cooperate with each other to further prevent arcing from occurring in the gap 304 between the electrostatic chuck 301 and the edge ring assembly 302 .

Based on the same inventive concept, this embodiment also provides a plasma processing device, including a chamber and a lower electrode assembly as described above. The lower electrode assembly is disposed in the chamber. The plasma processing device in this embodiment can block the arc path between the electrostatic chuck 101 and the edge ring assembly 102, thereby preventing arc generation in the gap between the electrostatic chuck 101 and the edge ring assembly 102.

In this embodiment, the plasma processing device further includes an insulating window and an inductor coil. The insulating window is arranged above the chamber, and the inductor coil is arranged on the insulating window. The high-frequency radio frequency power supply applies radio frequency signals to the inductor coil. The inductor coil generates an alternating magnetic field and induces an alternating electric field in the chamber to achieve plasma dissociation of the process gas injected into the chamber through the side wall of the chamber, thereby realizing plasma Processing of the substrate to be processed.

It should be noted that this embodiment only illustrates that the plasma processing device is an inductively coupled plasma processing device (ICP), without specifically limiting it. In other words, in addition to the above-mentioned inductively coupled plasma processing device (ICP), the plasma processing device in this embodiment may also be a capacitively coupled plasma processing device (CCP) as shown in FIG. 5 or other Plasma processing equipment.

Please refer to Figure 6. Based on the same inventive concept, this embodiment also provides a method of assembling a lower electrode assembly; the lower electrode assembly 100 includes an electrostatic chuck 101. The electrostatic chuck 101 has a first bearing surface 1011 located in the middle and a surrounding middle. The height of the second bearing surface 1012 is lower than the height of the first bearing surface 1011 . Each step of the assembly method will be described in detail below.

S102. Place an isolation layer 103 on the second bearing surface 1012.

After the electrostatic chuck 101 is moved into the chamber of the plasma processing device, the isolation layer 103 is placed on the second bearing surface of the electrostatic chuck 101 .

S104. Place the edge ring component 102 on the isolation layer 103. A gap 104 is provided between the edge ring component 102 and the electrostatic chuck 101.

As shown in FIG. 1 , the isolation layer 103 has a flat annular structure before being squeezed by the lower surface of the edge ring assembly 102 .

S106. Press down the edge ring assembly 102 so that the edge ring assembly 102 presses the isolation layer 103.

As shown in FIG. 2 , after being squeezed by the lower surface of the edge ring assembly 102 , the isolation layer 103 is formed into an annular structure with an inner wall portion bulging upward. During the deformation process of the isolation layer 103, its inner side wall extends upward along the gap 104, and its outer side wall extends between the lower surface of the edge ring assembly 102 and the second bearing surface 1012 of the electrostatic chuck 101.

The assembly method of the lower electrode assembly 100 in this embodiment adds an isolation layer 103 of insulating material between the lower surface of the edge ring assembly 102 and the second bearing surface 1012 of the electrostatic chuck 101; the isolation layer 103 can isolate the electrostatic chuck 101 from the edge. The arc path between the ring assemblies 102 thereby avoids arcing in the gap 104 between the electrostatic chuck 101 and the edge ring assembly 102 .

In addition, since the isolation layer 103 is also a plastic material, when the isolation layer 103 is squeezed by the lower surface of the edge ring assembly 102, it will extend upward along the gap 104, so that the isolation layer 103 can more effectively isolate the electrostatic chuck 101 and the edge ring assembly. 102 , thereby more effectively avoiding arc generation in the gap 104 between the electrostatic chuck 101 and the edge ring assembly 102 .

In this embodiment, when the edge ring component 102 is pressed down, the isolation layer 103 is deformed and completely contacted with the lower surface of the edge ring component 102 and the second bearing surface 1012 .

In this embodiment, when the edge ring assembly 102 squeezes the isolation layer 103, the isolation layer 103 deforms and moves upward along the gap 104.

In this embodiment, the middle outer wall of the electrostatic chuck 101 has a weld; when the isolation layer 103 deforms and moves upward along the gap 104 to cover the weld, the pressing of the edge ring assembly 102 stops.

In this embodiment, the isolation layer 103 has a split structure and includes multiple split isolation layers 103; placing the isolation layer 103 on the second bearing surface 1012 specifically includes:

The plurality of split isolation layers 103 are placed on the second bearing surface 1012 respectively, and the plurality of split isolation layers 103 form an annular structure.

In this embodiment, the second load-bearing surface 1012 of the electrostatic chuck 101 has screw holes and screws installed in the screw holes; while placing the isolation layer 103 on the second load-bearing surface 1012, the isolation layer 103 covers the screw holes and screws. /or screws.

The above descriptions are only examples of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the present invention are included in the protection scope of the present invention.

100: Lower electrode assembly 101,301:Electrostatic sucker 1011: First bearing surface 1012: Second bearing surface 1013:The turning point 102,202,302: Edge ring assembly 1021,3021: Focus ring 1022,3022:Insert ring 103,203,303: Isolation layer 1031: Inside the isolation layer 104,304: Gap 105:Protective layer 2023: Inner Circular Staircase 306:Isolation ring d: ring width W: substrate S102, S104, S106: steps

In order to more clearly illustrate the technical solutions of the patent embodiments of the present invention, the drawings needed to describe the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the patent of the present invention. For those of ordinary skill in the technical field to which the present invention belongs, other drawings can be obtained based on these drawings without making any progressive changes. Figure 1 is a schematic structural diagram of the lower electrode assembly before the isolation layer is extruded by the edge ring assembly in an embodiment of the present invention; Figure 2 is a schematic structural diagram of the lower electrode assembly after the isolation layer is squeezed by the edge ring assembly in an embodiment of the present invention; Figure 3 is a schematic structural diagram of the lower electrode assembly before the isolation layer is extruded by the edge ring assembly in another embodiment of the present invention; Figure 4 is a schematic structural diagram of the lower electrode assembly before the isolation layer is extruded by the edge ring assembly in another embodiment of the present invention; Figure 5 is a schematic structural diagram of a plasma treatment device according to an embodiment of the present invention; and FIG. 6 is a flow chart of a method of assembling a lower electrode assembly in an embodiment of the present invention.

100: Lower electrode assembly

101:Electrostatic sucker

1011: First bearing surface

1012: Second bearing surface

1013:The turning point

102: Edge ring assembly

1021: Focus ring

1022:Insert ring

103:Isolation layer

1031: Inside the isolation layer

104: Gap

105:Protective layer

d: ring width

W: substrate

Claims (19)

A lower electrode assembly, which includes: an electrostatic chuck, having a first bearing surface located in the middle and a second bearing surface surrounding the middle, the height of the second bearing surface being lower than the height of the first bearing surface ; An edge ring component, surrounding the middle part of the electrostatic chuck, is disposed above the second bearing surface, and is provided with a gap between it and the middle part of the electrostatic chuck; and an isolation layer is disposed surrounding the middle part of the electrostatic chuck, and is located Between the lower surface of the edge ring component and the second bearing surface; the isolation layer extends upward along the gap after being squeezed by the lower surface of the edge ring component, so that the isolation layer is at least partially located between the edge ring component and the second bearing surface. between the middle parts of the electrostatic chuck; wherein the isolation layer is made of plastic insulating material. The lower electrode assembly of claim 1, wherein the isolation layer is at least partially located within the gap. The lower electrode assembly according to claim 1, wherein the isolation layer is made of flexible material. The lower electrode assembly according to claim 3, wherein the isolation layer is made of silicone. The lower electrode assembly according to claim 1, wherein the inner side of the isolation layer is in contact with the outer side wall of the middle part of the electrostatic chuck. The lower electrode assembly according to claim 1 or 5, wherein the isolation layer has a ring structure; the ring width of the isolation layer is at least three times the width of the gap. The lower electrode assembly according to claim 6, wherein the ring width of the isolation layer is greater than or equal to 1.5 mm. The lower electrode assembly according to claim 5, wherein the middle part of the electrostatic chuck The outer wall has a weld; the inner side of the isolation layer covers the weld on the electrostatic chuck. The lower electrode assembly of claim 1, wherein the second bearing surface of the electrostatic chuck has a screw hole and a screw installed in the screw hole; the isolation layer covers the screw hole and/or the screw . The lower electrode assembly of claim 1, wherein the lower surface of the edge ring assembly is provided with an inner annular step; the inner annular step matches the isolation layer. The lower electrode assembly of claim 1, wherein the upper surface of the isolation layer is in contact with the lower surface of the edge ring assembly; the lower surface of the isolation layer is in contact with the second bearing surface of the electrostatic chuck. The lower electrode assembly of claim 1, wherein a protective layer is coated on the surface of the electrostatic chuck. The lower electrode assembly of claim 1, wherein the edge ring assembly includes an insertion ring in contact with the isolation layer and a focus ring located above the insertion ring; between the inner wall of the focus ring and the electrostatic chuck Provided with an isolation ring. The lower electrode assembly according to claim 1, wherein the isolation layer has a split structure. A plasma processing device, which includes a chamber, and the lower electrode assembly as described in any one of claims 1 to 14, the lower electrode assembly being disposed in the chamber. An assembly method of a lower electrode assembly, wherein the lower electrode assembly includes an electrostatic chuck. The electrostatic chuck has a first bearing surface located in its middle and a second bearing surface surrounding its middle. The height of the second bearing surface Lower than the height of the first bearing surface; the method includes the following steps: placing an isolation layer on the second bearing surface; Place an edge ring component on the isolation layer with a gap between the edge ring component and the electrostatic chuck; and press down on the edge ring component so that the edge ring component squeezes the isolation layer; the edge ring component squeezes the isolation layer When the isolation layer is pressed, the isolation layer deforms and moves upward along the gap; wherein the isolation layer is a plastic insulating material. The assembly method of claim 16, wherein the middle outer wall of the electrostatic chuck has a weld; when the isolation layer deforms and moves upward along the gap to cover the weld, stop pressing the edge ring components. The assembly method as described in claim 16, wherein the isolation layer has a split structure and includes a plurality of split isolation layers; placing the isolation layer on the second bearing surface specifically includes the following steps: separately placing a plurality of split isolation layers The split isolation layer is placed on the second bearing surface, and the multiple split isolation layers form an annular structure. The assembly method as described in claim 16 or 17, wherein the second load-bearing surface of the electrostatic chuck has a screw hole and a screw installed in the screw hole; after placing the isolation layer on the second load-bearing surface At the same time, the isolation layer covers the screw hole and/or the screw.