Layered ceramic structure

Abstract

In some examples, a substrate support assembly includes: a monolithic ceramic body; a heater element disposed within the monolithic ceramic body; and an RF antenna disposed within the monolithic ceramic body. One or more power lines supply the heater element and the RF antenna. A layered structure is formed or included within the monolithic ceramic body, the layered structure including at least one layer having a thermal conductivity different from a thermal conductivity of the monolithic ceramic body.

Description

[0001] Priority claim

[0002] This patent application claims priority to U.S. Provisional Patent Application Serial No. 62 / 818,591 (Agent Docket No. 4948.042PRV), filed by Hollingsworth et al. on March 14, 2019, and entitled “Lamellar Ceramic Structure,” all contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to layered ceramic structures and, more particularly, to substrate support assemblies including layered ceramic structures for use in wafer processing chambers in semiconductor manufacturing operations. Background Art

[0004] The background description provided here is for the purpose of generally presenting the context of the present disclosure. The work of the presently designated inventors is neither explicitly nor implicitly admitted to be prior art to the present disclosure to the extent that it is described in this background section and in aspects of the specification that were not determined to be prior art at the time the application was filed.

[0005] Ceramic pedestals and electrostatic chucks can have localized hot spots that change the thermal dynamics or conditions of wafer processing. Two significant causes of hot spots include insufficient heat dissipation and inconsistent (or non-repeatable) positioning of the heater element within the ceramic body of the chuck. Thicker ceramic bodies can dissipate heat more evenly, but the raw material and processing costs to achieve this result using today's technology are often prohibitively high. Added thermal mass can also reduce tool throughput. Movement of raw material powder during processing can negatively impact position repeatability.

[0006] In addition, ceramic pedestals and electrostatic chucks are susceptible to mechanical failure from thermal stresses. For example, ceramic pedestals and electrostatic chucks formed by hot pressing may encounter certain limitations inherent to this method. In some cases, the total output of the hot pressing operation may be limited by the mass of the preform, which is configured to fit into the mold of an existing hot press. The hot pressing operation may be further limited by the density of the preform before sintering. Summary of the invention

[0007] In some examples, a substrate support assembly includes: a monolithic ceramic body; a heater element disposed within the monolithic ceramic body; an RF antenna disposed within the monolithic ceramic body; one or more power lines that supply the heater element and the RF antenna; and a layered structure formed or included within the monolithic ceramic body, the layered structure including at least one layer, the thermal conductivity of the at least one layer being different from the thermal conductivity of the monolithic ceramic body.

[0008] In some examples, the at least one layer is disposed, in use, over the heater element.

[0009] In some examples, the at least one layer is disposed, in use, beneath the heater element.

[0010] In some examples, the at least one layer includes a ceramic material.

[0011] In some examples, the at least one layer includes a metallic material or an intermetallic material.

[0012] In some examples, the layered structure includes at least two layers, and wherein the thermal conductivity of one of the at least two layers is different from at least one of the other layers in the layered structure.

[0013] In some examples, at least one layer of the layered structure has a thermal conductivity that is different than a thermal conductivity of the monolithic ceramic body.

[0014] In some examples, the layered structure includes at least two layers, wherein each of the at least two layers has a thermal conductivity different from any other layer in the layered structure.

[0015] In some examples, at least one layer of the layered structure includes a pressureless sintered aluminum nitride plate.

[0016] In some examples, the layered structure includes a silicon nitride (Si 3 N 4 ) mesh that reacts with a material of the monolithic ceramic body when formed or included within the monolithic ceramic body.

[0017] Further examples are described in the description below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Some embodiments are shown in the accompanying drawings by way of example and not by way of limitation:

[0019] Figure 1 A simplified example of a plasma-based processing chamber is shown that may include a substrate support assembly including an electrostatic chuck (ESC) for supporting a substrate during plasma processing.

[0020] Figure 2 According to one example, aspects of a conventional substrate support assembly without a layered structure are shown.

[0021] Figure 3 Examples according to the present disclosure show aspects of an exemplary substrate support assembly.

[0022] Figure 4 A flow chart showing exemplary operations in a method is shown according to an exemplary embodiment. DETAILED DESCRIPTION

[0023] The following description includes systems, methods, and techniques for implementing the illustrative embodiments of the present disclosure. In the following description, for the purpose of explanation, many specific details are set forth to provide a thorough understanding of the exemplary embodiments. However, it is apparent to those skilled in the art that the subject matter of the present invention can be implemented without these specific details.

[0024] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the accompanying drawings that form a part of this document: LAM Research Corporation, 2019-2020, All Rights Reserved.

[0025] Reference now Figure 1 , showing an example of a plasma-based processing chamber. The present subject matter can be used in various semiconductor manufacturing and wafer processing operations, but in the examples shown, the plasma-based processing chamber is described in the context of plasma-enhanced or free radical-enhanced chemical vapor deposition (CVD) or atomic layer deposition (ALD) operations. It should also be understood by those skilled in the art that other types of ALD processing techniques are known (e.g., thermal-based ALD operations) and can be combined with non-plasma-based processing chambers. Atomic layer deposition (ALD) tools are special types of chemical vapor deposition (CVD) processing systems, in which the ALD reaction occurs between two or more chemical substances. The two or more chemical substances are called precursor gases and are used to form a thin film deposition of materials on a substrate, such as a silicon wafer used in the semiconductor industry. The precursor gases are sequentially introduced into the ALD processing chamber and react with the substrate surface to form a deposited layer. Generally speaking, the substrate repeatedly interacts with the precursor to slowly deposit a gradually thickening layer of one or more material films on the substrate. In some applications, a variety of precursor gases can be used during the substrate manufacturing process to form one or more layers of various types of films.

[0026] Figure 11 is shown to include a plasma-based processing chamber 101 in which a showerhead 103 (which may be a showerhead electrode) is disposed, and a substrate support assembly 107. The substrate support assembly 107 may, for example, include a susceptor as described in detail below. Generally, the substrate support assembly 107 seeks to provide a substantially constant temperature surface, and may act as a heating element and heat sink for the substrate 105. The substrate support assembly 107 may include an electrostatic chuck (ESC) including a heating element to assist in processing the substrate 105 as described herein. The substrate 105 may include: a wafer including an elemental semiconductor (e.g., silicon or germanium); a wafer including a compound element (e.g., gallium arsenide GaAs, or gallium nitride GaN); or various other substrate types (including conductive, semiconductive, and non-conductive substrates).

[0027] In operation, a substrate 105 is loaded onto the substrate support assembly 107 through the loading port 109. A gas line 113 can supply one or more process gases (e.g., precursor gases) to the showerhead 103. The showerhead 103 then delivers the one or more process gases into the plasma-based processing chamber 101. A gas source 111 (e.g., one or more precursor gas ampoules) that supplies the one or more process gases is coupled to the gas line 113. In some examples, an RF power source 115 is coupled to the showerhead 103. In other examples, the power source is coupled to the substrate support assembly 107 or the ESC.

[0028] A point of use (POU) and manifold combination (not shown) controls one or more process gases into the plasma-based processing chamber 101 before entering the showerhead 103 and downstream gas lines 113. In the case where the plasma-based processing chamber 101 is used in a plasma enhanced ALD (PEALD) operation to deposit thin films, the precursor gases may be mixed in the showerhead 103.

[0029] In operation, the plasma-based processing chamber 101 is evacuated by a vacuum pump 117. RF power is capacitively coupled between the showerhead 103 and a lower electrode (not explicitly shown), which is contained in or located on the substrate support assembly 107. The substrate support assembly 107 is typically supplied by two or more RFs. For example, in various embodiments, the RF can be selected from at least one frequency at about 1 MHz, 2 MHz, 13.56 MHz, 27 MHz, 60 MHz, and other required frequencies. The coil can be designed as required to block or partially block a specific RF. Therefore, the specific frequencies discussed herein are provided only for ease of understanding. RF power is used to excite one or more processing gases into a plasma in the space between the substrate 105 and the showerhead 103. The plasma can assist in depositing various layers (not shown) on the substrate 105. In other applications, the plasma can be used to etch device features into various layers on the substrate 105. RF power is coupled at least through the substrate support assembly 107. The substrate support assembly 107 may have a heater incorporated therein (not shown). Figure 1 Detailed design of the plasma-based processing chamber 101 is variable.

[0030] Reference now Figure 2 , which shows features of a simplified example of a conventional substrate support assembly (or pedestal) 200. The exemplary substrate support assembly 200 does not include the layered structure of the present disclosure. This conventional example 200 will generally encounter one or more of the limitations described above, including insufficient heat dissipation and hot spot formation. The conventional substrate support assembly 200 includes a pedestal body 202, in which a heater element 204 is disposed. The pedestal body 202 also includes an RF / ESC electrode 206. The pedestal body 202 is supported by a mechanical support such as a rod 208. Lines 212 and 214 (e.g., power lines or conductors) that supply power to the heater element 204 and the RF / ESC electrode 206 pass through the rod 208, respectively. During wafer processing, the substrate support assembly 200 supports a substrate 105 such as a silicon (Si) wafer 210.

[0031] To address at least some of the challenges described above, some examples of the present disclosure include an anisotropic composite structure (e.g., a layered structure) formed within the body of the substrate support assembly 200. In some examples, the body of the substrate support assembly 200 includes a monolithic ceramic material or body. The layered structure within the monolithic ceramic material may include one or more material layers having a relatively high or low thermal conductivity compared to the thermal conductivity of the ceramic material of the body of the substrate support assembly 200. In some examples, the material layer having a relatively high thermal conductivity may enhance heat flow to a specified area of ​​the ceramic body of the substrate support assembly 200, or to other areas of the substrate support assembly 200. In some examples, the material layer having a relatively low thermal conductivity may prevent heat flow to a specified area of ​​the ceramic body of the substrate support assembly 200, or to other areas of the substrate support assembly 200. The material layers of different thermal conductivities may be selected to be uniformly or mixedly combined and disposed within the ceramic body of the substrate support assembly 200. In some examples, the combination of material layers can enhance or inhibit heat from spreading laterally or vertically within a predetermined thickness or portion of the ceramic body of the substrate support assembly 200.

[0032] In some examples, thermal conductivity can be defined as the amount of heat that passes through a unit area of ​​a material (whose thickness is uniform) per unit time when the temperatures of opposite surfaces of the material differ by one degree. The SI derived unit of thermal conductivity is Watts per meter Kelvin (Wm -1 .K -1 ).

[0033] In some examples, the layered structure within the ceramic body of the substrate support assembly 200 includes: stacked material layers or components with relatively high thermal conductivity, which extend along the lateral direction of the substrate support assembly 200; and layers (lamina) with relatively low thermal conductivity, which are arranged along the vertical direction of the substrate support assembly 200.

[0034] In some examples, the layered structure located in the ceramic body is formed during the sintering and hot pressing operations. In some examples, one or more ceramic material plates with relatively low thermal conductivity are selected to form the layers of the layered structure. In some examples, the plates can be sintered to a portion of the theoretical density of the ceramic body. The density level can be selected to optimize the adhesion of the plates during the hot pressing of the ceramic body of the substrate support assembly 200. In some examples, the plates are machined to the desired geometry, and surface treatment and / or coatings can be optionally provided to further improve the adhesion of the plates in the ceramic body. In some examples, the layered structure is designed to make it easier or faster for heat to flow in the longitudinal direction of each layer, rather than in the direction of stacking of the layers.

[0035] In some examples, a preform (or "green structure") is formed that includes a layered structure embedded in a ceramic body. In some examples, at least one ply in the layered structure is formed by sintering a powder of the preform. In some examples, the overall layered structure is not formed until the entire ceramic body is sintered. The layered structure may include: one or more layers composed of, or including, sintered metal or ceramic plates. The preform may include a ceramic base or other internal structures or components of the ESC, such as circuits for heater elements 204, RF electrodes 206, clamping electrodes, etc. The internal structures or components of the preform may be embedded in a compressed powder having a composition different from the ceramic body into which they are to be embedded. The compressed powder may be selected to enhance or inhibit the thermal conductivity and / or adhesion of the internal structures or components.

[0036] In some examples, the preform is then hot pressed so that the various powders and plates therein are bonded together as the preform is sintered to achieve or approach a desired theoretical density. In some examples, one or more layers of the layered structure having a selected thermal conductivity profile may be formed of or include another material (e.g., metal) or structure (e.g., metal mesh). These exemplary materials or structures may be formed of or include a metal sheet, screen, mesh, or by screen printing a metal (or metallic) layer on a layer to form a composite structure.

[0037] In some examples, one or more layers of the layered structure may comprise a ceramic material and may be arranged, for example, as described above, and further include a coating. Exemplary coatings may include additives or may have properties enhanced or modified by chemical surface treatments, such as locally altering the thermal conductivity of the coating or the material to which the coating has been applied. In some examples, a plate comprising a high thermal conductivity material is coated with a selected substance or mixture of substances to reduce the thermal conductivity of its top and bottom surfaces during subsequent heat treatment of the ceramic body. In some examples, the layered structure within the ceramic body comprises three layers, each of which has, or the sum of which has, a thickness in the range of 0.1 mm to 5 mm.

[0038] In some examples, a layer in a layered structure includes multiple sublayers. The combined thickness of the multiple sublayers is equal to or close to the thickness of the layer. The top and bottom sublayers in the sublayer arrangement may have a certain thickness, which is the diffusion distance (if the center sublayer forms a solid solution) or may be controlled by the amount of coating added to the center sublayer. The unreacted center layer may have a certain thickness, which is determined by the depth of the reaction that forms the top and bottom sublayers.

[0039] In some examples, one or more layers of the layered structure may include a homogeneous or solid material plate, which is selected to react with the surrounding ceramic material of the ceramic body during sintering, or to dissolve into the surrounding ceramic material of the ceramic body, thereby locally modifying the thermal conductivity of itself or the ceramic body to achieve the heat transfer distribution required for the layered structure within the ceramic body. Typically, hot pressing removes voids and channels. In some examples, other methods are used to specifically create a preformed structure or ceramic body to form or include internal voids or channels therein. Predetermined voids or channels can be set on a specific layer of the layered structure, or adjacent to a specific layer of the layered structure, and configured to provide the desired heat transfer (thermal conductivity) distribution. In some examples, the ceramic body may include a sintered sacrificial layer, which can be removed by chemical etching after all high temperature processing is completed.

[0040] Some examples can address thermal conductivity issues related to non-repeatable component placement. Some examples use a fiducial or base structure by including a rigid sheet or platform, such as a suitable material, within a ceramic body of a substrate support assembly 200 (e.g., a pedestal) to constrain the relative position of other pedestal components during fabrication of the ceramic body. The ceramic body can include a layered structure as a constraining component, according to one or more of the above types.

[0041] In some examples, a pre-sintered plate or platform configured as a reference structure is located in a preform of the ceramic body and adjacent to the plane of the heater circuit to reduce the effects of initial density variations within the ceramic body during sintering in the final position of the heating elements of the heater circuit.

[0042] In some examples, the reference structure includes a ceramic plate that is configured to receive the heater element 204 in only a desired or fixed configuration. Fasteners and / or a suitable adhesive can be used to attach the heater element 204 to the ceramic plate. In some examples, a sinterable preform can be attached to the ceramic plate prior to placement in the mold, and the preform can be further configured to constrain the position of the heating element during sintering.

[0043] Some examples herein may address the vulnerability of a substrate support assembly 200 or a ceramic body including a layered structure to thermal stress. Here, in some examples, one or more structural elements (e.g., plates, rings, beams, or other suitable elements) having desired structural properties are placed within a preform, layered structure, or ceramic body to offset expected thermal stresses that may occur at or within the surface of the associated preform, layered structure, or body. In some examples, the coefficient of thermal expansion (CTE) of one or more structural members within the preform, layered structure, or ceramic body is greater than the bulk of the ceramic material within which they are disposed. Tensile stresses may be induced in the structural member due to the difference between the processing temperature at which the structural member obtains its final shape and the operating temperature of the ceramic body or base or ESC using the structural member.

[0044] In some examples, the preform, layered structure, or ceramic body is heat treated after sintering at a temperature at which the high CTE structural members embedded therein deform at a rate greater than the surrounding material in which they are placed (e.g., by creep deformation). The higher deformation rate can relieve thermal stresses within the layered structure or ceramic body preform, and in some examples, provide that relief to a specific controlled or desired level.

[0045] In some examples, one or more different parts or components of a preform, layered structure, or ceramic body can be designed to experience different creep rates, such as by using selective heat treatment, alloying, doping, or other methods to control or produce the final stress distribution. Some examples may, for example, include the above-mentioned ceramic structural elements, which are coated with additives or modified by chemical surface treatments to locally change the thermal expansion coefficient of the material surrounding the structural element. The material of the structural element can be selected and added to the preform so that it reacts with the surrounding ceramic material in a specific way during sintering, or dissolves into the surrounding ceramic material. The reaction or dissolution can modify the thermal expansion coefficient, and in some examples, the added material can actually constitute a layer of a structural member or layered structure in the surrounding bulk ceramic material, or be included in a layer of a structural member or layered structure.

[0046] Some examples herein can solve problems associated with limited mold space in hot pressing, or more generally with problems associated with the configuration of "equipment" (e.g., including molds, boats, crucibles, etc.) in high temperature processing. Some examples include increasing the amount of ceramic material in the mold before sintering, and / or reducing the ceramic thickness required to achieve a given thermal uniformity specification. In some examples, one or more ceramic material plates (e.g., to form one or more layers of a layered structure) are sintered without applying pressure and then added to one or more preforms. The conventional height of each preform can be reduced to give the mold material a minimized final volume, and this can make it possible to install a greater number of preforms into a given mold.

[0047] In some examples, the design of the substrate support assembly 200 (pedestal) is configured to take advantage of improved heat dissipation. For example, the wafer 210 can be placed closer to the heating element than conventionally without sacrificing thermal uniformity while enabling a thinner ceramic body to achieve the same or similar wafer handling performance. This approach can result in savings in raw materials and hot press capacity.

[0048] Thus, in some examples, incorporating one or more plates or layers of materials having different thermal conductivities into a substrate support structure (e.g., a ceramic pedestal, or a monolithic ceramic body) can impart anisotropic thermal properties to the substrate support assembly 200 and enable improved heat dissipation performance. Such incorporation of plates or layers can be performed prior to sintering the ceramic body material within which they are placed. The method can also enable the construction of a pre-stressed ceramic body for the pedestal to have improved fracture resistance. Some examples herein can be used to achieve greater control over the internal structure within the ceramic body and increase the throughput of the system that manufactures these pedestals.

[0049] Reference now Figure 3 , which shows aspects of an exemplary substrate support assembly 300 according to the present disclosure. The exemplary substrate support assembly 300 includes an exemplary layered structure 316 of the present disclosure. The exemplary substrate support assembly 300 attempts to address one or more limitations discussed further above, including insufficient heat dissipation and the formation of hot spots. The substrate support assembly 300 includes a susceptor body 302, in which a heater element 304 is disposed. The susceptor body 302 may include a monolithic ceramic body or be composed of a monolithic ceramic body. The susceptor body 302 also includes an RF / ESC electrode 306. The susceptor body 302 is supported by a mechanical support such as a rod 308. Power lines 312 and 314 supply power to the heater element 304 and the RF / ESC electrode 306. In some examples, as shown, the lines 312 and 314 pass through the rod 308. During substrate processing, the substrate support assembly 300 supports a substrate 105 such as a silicon (Si) wafer 310.

[0050] In the example shown, the layered structure 316 includes two layers 318 and 320, which are arranged in a layered or layered manner with one vertically disposed above the other. In some examples, the surrounding or adjacent ceramic material of the substrate support assembly 300 can be considered to constitute three additional layers, which are respectively disposed below, between, and above the layers 318 and 320. The layered structure 316 of this example would therefore include five layers. Many other configurations of the layered structure 316 are possible.

[0051] In some examples, each layer of the layered structure 316 can increase or decrease (retard) thermal conductivity in the length direction (i.e., lateral to the assembly 300, or horizontal in view) of the layered structure 316. In some examples, each vertically positioned layer of the layered structure 316 can have a different thermal conductivity than at least one other layer in the structure 316, so that a variable heat transfer distribution is generated in the vertical direction of the substrate support assembly 300 and / or in the lateral direction of the substrate support assembly 300.

[0052] In some examples, the upper layer 318 of the layered structure 316 includes a material having a lower thermal conductivity than the surrounding ceramic material of the susceptor body 302. The reduced thermal conductivity can hinder the heat emitted from the heater element 304 from flowing directly upward toward the substrate 310. In some examples, this configuration, for example, helps to direct the emitted heat to flow laterally toward the cooler area of ​​the susceptor body 302 (which supports the periphery of the substrate). Heat is hindered from traveling along the path from the heater element 304 to the substrate 310 so that it can diffuse laterally. In some examples, the lower layer 320 of the layered structure 316 can, for example, hinder heat from flowing downward from the heater element 304 to the rod 308 and dissipated as waste heat. In some examples, for example, the potentially wasted heat can be retained and allowed to diffuse laterally relatively quickly within the support assembly 300 and then upward to assist in substrate processing operations.

[0053] Other layer configurations and materials may be selected for the layered structure 316 to provide a desired heat transfer or thermal conductivity distribution in the base body 302. For example, only one upper layer 318 or lower layer 320 may be provided. Some layers in the layered structure 316 may be disposed on one or both sides of the heater element 304. In some examples, the thermal conductivity and / or materials of the upper layer 318, lower layer 320, side layers (not shown), and ceramic materials of the base body 302 may each be different and selected to provide a given thermal conductivity distribution. The size and specific location of the layers may be different and / or selected to provide a desired heat transfer or thermal conductivity distribution for the base body 302. For example, the layered structure 316 may include one or more pressureless sintered, low thermal conductivity aluminum nitride (AlN) plates that are placed in a ceramic preform and then sintered to form a ceramic base body 302 in which the one or more plates are embedded and define the layered structure 316. Another exemplary layered structure 316 or ceramic base body 302 may include an embedded grid of silicon nitride (Si 3 N 4 ) that reacts with surrounding materials (eg, aluminum nitride) to create a reduced thermal conductivity layer within the ceramic base body 302 .

[0054] In some examples, the heater element 304 can be disposed in a heater zone. In some examples, one or more heater zones can be disposed within the susceptor body 302. Each heater zone can include multiple heater elements 304. In some examples, for example, the RF antenna 306 (e.g., a grid, or mesh) is disposed within the susceptor body 302, rather than in the external showerhead 103 outside the susceptor body 302. Placing the RF antenna 306, which is itself a thermally conductive element, internally can help control heat flow within the susceptor body 302 or to the silicon wafer 310.

[0055] In some examples, one or more layers forming the layered structure 316 within the base body 302 may each include a homogeneous (solid) or composite material or component. The one or more layers may, for example, be arranged at different heights in a continuous or discontinuous grid structure within the base body 302. The grid structure may (or may not) surround the heater element 304 laterally or vertically within the base body 302. An offset dimension, in other words, the distance between the grid structure elements or (for example) layers 318 or 320 within the layered structure 316 and the heater element 304, may be selected to provide a desired heat transfer or thermal conductivity distribution. An offset dimension about an outer edge or surface of the base body 302 may be similarly established.

[0056] In some examples, the thermal conductivity of the layers within the layered structure 316 may be in the range of 5 to 200 W / m·K. In some examples, the thermal conductivity of the layered structure 316 in the susceptor body 302 may be in the range of 75 to 100 W / m·K. In some examples, the thermal conductivity of the monolithic ceramic susceptor body 302 may be in the range of 150 to 190 W / m·K.

[0057] In some examples, the rod 308 material includes the same material as the layer 318 or 320 within the base body 302. In some examples, the layer 318 or 320 (or a portion thereof) is disposed at the junction between the layer and the rod 308.

[0058] The outer dimensions of the solid or composite layer 318 or 320 within the layered structure 316 can be selected to conform to a given configuration or desired heat transfer characteristics of the base or ceramic body. The outer shape or outline of the layer 318 or 320 within the layered structure 316 can include a square, rectangular, circular architecture, or a combination thereof.

[0059] The material of the specific layer may include a metallic material or an intermetallic material. The material of the layer may include aluminum nitride, aluminum silicon nitride, aluminum oxynitride, yttrium aluminate, magnesium aluminate, tungsten, molybdenum, copper, carbon, boron nitride, and a composite structure composed of the above materials. The specific base body material may include aluminum nitride, aluminum oxynitride, aluminum oxide, silicon aluminum nitride, silicon aluminum oxynitride, yttrium aluminate, magnesium aluminate, and a composite structure composed of the above materials.

[0060] The present disclosure also includes exemplary method embodiments. Figure 4 , the method 400 of forming the substrate support assembly 300 may include: at operation 402, forming a monolithic ceramic body by shaping a preform, the preform including a ceramic material; at operation 404, including a heater element 304 in the preform; at operation 406, including an RF antenna 306 in the preform; at operation 408, providing one or more power lines 312, 314 in the preform to supply power to the heater element 304 and the RF antenna 306 when in use; at operation 410, including or forming a layered structure 316 in the preform, the layered structure 316 when formed including at least one layer having a thermal conductivity different from the thermal conductivity of the monolithic ceramic body; and, at operation 412, sintering the preform.

[0061] In some examples, the method 400 may also include disposing the at least one layer over the heater element 304 within the monolithic ceramic body.

[0062] In some examples, the method 400 may also include disposing the at least one layer below the heater element 304 within the monolithic ceramic body.

[0063] In some examples, the method 400 may also include embedding or including a ceramic material in the at least one layer.

[0064] In some examples, the method 400 may further include: including a metallic material in the at least one layer.

[0065] In some examples, the method 400 may also include including at least two layers in the layered structure 316 , wherein a thermal conductivity of one of the at least two layers is different from at least one of the other layers in the layered structure 316 .

[0066] In some examples, the method 400 may also include including at least two layers in the layered structure 316 , wherein each of the at least two layers has a thermal conductivity different from any other layer in the layered structure 316 .

[0067] In some examples, the method 400 may also include including at least two layers in the layered structure 316 , wherein a thermal conductivity of at least one layer of the layered structure 316 is different than a thermal conductivity of the monolithic ceramic body.

[0068] In some examples, the method 400 further includes including a pressureless sintered aluminum nitride plate in at least one layer of the layered structure 316 .

[0069] In some examples, the method 400 further includes including a grid of silicon nitride (Si 3 N 4 ) in the layered structure 316 , the silicon nitride (Si 3 N 4 ) reacting with the material of the monolithic ceramic body when the preform is sintered.

[0070] Although the embodiments have been described with reference to specific examples, it is apparent that various modifications and changes may be made to these embodiments without departing from the broader scope of the present disclosure. Therefore, the specification and the drawings are to be regarded as illustrative and not restrictive. The drawings forming part thereof show specific embodiments of the practicable subject matter in an illustrative and not restrictive manner. The embodiments shown are described in sufficient detail to enable those skilled in the art to implement the teachings disclosed herein. Other embodiments may be used and derived therefrom so that structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Therefore, this detailed description is not to be regarded as restrictive, and the scope of the various embodiments is limited only by the appended claims and the full scope of equivalents to which these claims are assigned.

[0071] In this article, these embodiments of the subject matter of the invention may be referred to as the term "invention" independently and / or collectively for convenience only, and if more than one is actually disclosed, it is not intended to limit the scope of the application to any single invention or inventive concept. Therefore, although specific embodiments have been illustrated and described herein, it should be understood that for the specific embodiments shown, any configuration calculated to achieve the same purpose can be used to replace them. The present disclosure is intended to cover any and all adaptations and changes of the various embodiments. By reviewing the above description, the combination of the above embodiments with other embodiments not specifically described herein will be obvious to those skilled in the art.

Claims

1. A substrate support assembly comprising: Monolithic ceramic body; a heater element disposed within the monolithic ceramic body; an RF antenna disposed within the monolithic ceramic body; a rod supporting the monolithic ceramic body; one or more power lines that supply the heater element and the RF antenna; a layered structure formed or included within the monolithic ceramic body, the layered structure including at least one layer therein, the thermal conductivity of the at least one layer being different from the thermal conductivity of the monolithic ceramic body, wherein the at least one layer is arranged below the heater element when in use, the rod is arranged below the at least one layer, and the one or more power lines pass through the rod.

2. The substrate support assembly of claim 1, wherein the at least one layer comprises a ceramic material.

3. The substrate support assembly of claim 1, wherein the at least one layer comprises a metallic material or an intermetallic material.

4. The substrate support assembly of claim 1, wherein the layered structure comprises at least two layers, and wherein the thermal conductivity of one of the at least two layers is different from at least one of the other layers in the layered structure.

5. The substrate support assembly of claim 4, wherein at least one layer of the layered structure has a thermal conductivity that is different from a thermal conductivity of the monolithic ceramic body.

6. The substrate support assembly of claim 1, wherein the layered structure comprises at least two layers, and wherein each of the at least two layers has a thermal conductivity different from any other layer in the layered structure.

7. The substrate support assembly of claim 1, wherein at least one layer of the layered structure comprises a pressureless sintered aluminum nitride plate.

8. The substrate support assembly of claim 1, wherein the layered structure comprises a silicon nitride (Si3N4) mesh that reacts with a material of the monolithic ceramic body when formed or included within the monolithic ceramic body.

9. A method of forming a substrate support assembly, the method comprising: forming a monolithic ceramic body by shaping a preform, the preform comprising a ceramic material, the monolithic ceramic body being supported by a rod; including a heater element in said preform; including an RF antenna in the preform; providing one or more power lines in the preform to supply power to the heater element and the RF antenna in use, the one or more power lines passing through the rod; including or forming a layered structure in the preform, the layered structure when formed comprising at least one layer, the at least one layer having a thermal conductivity different from the thermal conductivity of the monolithic ceramic body; as well as The preform is sintered wherein the rod is disposed beneath the at least one layer and the method further comprises arranging the at least one layer, in use, beneath the heater element within the monolithic ceramic body.

10. The method according to claim 9, further comprising: A ceramic material is embedded in or included in the at least one layer.

11. The method according to claim 9, further comprising: A metallic material is included in the at least one layer.

12. The method according to claim 9, further comprising: At least two layers are included in the layered structure, wherein the thermal conductivity of one of the at least two layers is different from at least one of the other layers in the layered structure.

13. The method of claim 9, further comprising including at least two layers in the layered structure, wherein each of the at least two layers has a thermal conductivity different from any other layer in the layered structure.

14. The method according to claim 9, further comprising: At least two layers are included in the layered structure, wherein the thermal conductivity of the at least one layer of the layered structure is different from the thermal conductivity of the monolithic ceramic body.

15. The method according to claim 9, further comprising: A pressureless sintered aluminum nitride plate is included in the at least one layer of the layered structure.

16. The method according to claim 9, further comprising: A silicon nitride (Si3N4) network is included in the layered structure, and when the preform is sintered, the silicon nitride (Si3N4) reacts with the material of the monolithic ceramic body.

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