Um-based configuration

Abstract

To provide a method for bonding an electrostatic chuck to a temperature controlled base.SOLUTION: A method forms a bonding layer 106 between a dielectric 102 including an electrostatic chuck and a temperature-controlled base 104, with flow apertures 112 penetrating the dielectric and aligned with the flow apertures in the temperature-controlled base. The bonding layer is also configured with an opening that aligns with the apertures in the dielectric and the temperature-controlled base. In one embodiment, a porous plug may be placed in the flow aperture to protect the bonding layer. In another embodiment, a seal may be placed in the flow aperture to seal the bonding layer against gases within the flow aperture.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] (Technical field) FIELD OF THE DISCLOSURE Embodiments of the present disclosure generally relate to bonding layers for electrostatic chucks. Description of Related Art

[0002] Electrostatic chucks are used in a variety of manufacturing and processing operations. In semiconductor manufacturing, electrostatic chucks are typically used to support a substrate within a processing chamber. During semiconductor manufacturing, the substrate support, including the electrostatic chuck, is exposed to temperatures ranging between the ambient temperature of the processing chamber and the substrate processing temperature. To maintain the substrate temperature at a desired set point, the electrostatic chuck, which is formed from ceramic, is connected to a temperature control base. A conductive bonding material between the ceramic chuck portion and the temperature control base couples the two.

[0003] The substrate support includes a bonding material that is exposed at the interface between the electrostatic chuck and the cooling base at any backside gas flow path through the substrate support. The substrate support is exposed to process gases and process reaction byproducts of the manufacturing process. Some of these gases and byproducts can degrade the bonding material upon contact with it. Variations in the bonding material also arise during its manufacture and formation. These variations in adhesive strength and material properties can cause the bonding material to delaminate from the electrostatic chuck and the temperature control base, or locally alter heat transfer in the bonding material, which causes temperature variations across the chuck surface of the electrostatic chuck. Furthermore, the electrostatic chuck and the temperature control base may have different thermal expansion coefficients. As the temperature of the substrate support increases, such as during a processing operation, or as the temperatures of the dielectric and the temperature control base differ, stress in the bonding material increases due to the difference in thermal expansion between the electrostatic chuck and the temperature control base. This increased stress can cause localized delamination of the bonding material if the localized stress exceeds the bonding strength of the bonding material. Overview

[0004] The present disclosure generally relates to a bonding layer for securing a ceramic body to a metal body. A flow aperture extends through the body. A plug and seal are optionally disposed within the flow aperture to protect the bonding layer. In some embodiments, the bonding layer may comprise two layers to form a graded bond profile. [Brief explanation of the drawings]

[0005] In order that the above-described features of the present disclosure may be understood in detail, a more particular description of the disclosure briefly summarized above will now be made with reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only exemplary embodiments and therefore should not be construed as limiting the scope thereof, which may include other equally effective embodiments. [Figure 1] 1 is a cross-sectional schematic view of an exemplary substrate support. [Figure 2A] ~ [Figure 2B] 1 is a cross-sectional schematic view of a bonding structure for securing an electrostatic chuck and a temperature control member together according to one embodiment. [Figure 3] 1 is a cross-sectional schematic view of a bonding structure for securing an electrostatic chuck and a temperature control member together according to one embodiment. [Figure 4] 1 is a cross-sectional schematic view of a bonding structure for securing an electrostatic chuck and a temperature control member together according to one embodiment.

[0006] To facilitate understanding, the same reference numerals have been used, whenever possible, to designate identical elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation thereof. DETAILED DESCRIPTION

[0007] Disclosed herein is a method for bonding an electrostatic chuck to a temperature control base. In one embodiment, a bonding layer is formed between a dielectric material comprising the electrostatic chuck and the temperature control base. A flow aperture penetrates the dielectric material and aligns with the flow aperture in the temperature control base. The bonding layer is configured with an opening, and the opening aligns with the aperture in the dielectric material and the temperature control base. In one aspect, a porous plug may be disposed within the flow aperture to protect the bonding layer from gas present within the flow aperture. In another aspect, a seal is disposed within the flow aperture to seal the bonding layer against gas present within the flow aperture.

[0008] FIG. 1 is a schematic cross-sectional view of an exemplary substrate support used in a processing chamber. The substrate support 100 includes a dielectric 102 and a temperature control base 104 that constitute an electrostatic chuck. The dielectric includes a ceramic material (e.g., alumina or alumina nitride). The temperature control base 104 includes a metal (e.g., aluminum). The temperature control base 104 is fixed to a cylindrical support post (not shown), which extends through the wall of the processing chamber to support the substrate support 100. Alternatively, the temperature control base can be fixed to a base inside the chamber. The substrate support 100 generally has a circular shape, but other shapes capable of supporting a substrate, such as a rectangular or oval shape, can also be used. A bonding layer 106 is disposed between the bottom surface of the dielectric 102 facing the temperature control base 104 and the top surface of the dielectric 102, opposite the cylindrical support post of the temperature control base 104. A substrate W can be removably disposed on the top surface of the dielectric 102, which is the surface opposite the bonding layer 106. The bonding layer 106 secures and thermally connects the dielectric 102 to the temperature control base 104 .

[0009] An electrode 108 is disposed within the dielectric 102. The electrode 108 is connected to a power supply (not shown), which applies a voltage to the electrode to create an electromagnetic field at the interface between the top surface of the dielectric 102 and the substrate W. The electromagnetic field interacts with the substrate W to chuck the substrate W to the surface of the dielectric 102. The electrode may be biased to provide a monopolar or bipolar chuck.

[0010] Channels 110 disposed within the temperature control base 104 circulate a fluid within the temperature control base 104. The fluid, typically a liquid such as Galden™, flows from a temperature control unit (not shown) through the channels 110 and back to the temperature control unit. In some processes, the fluid is used to cool the temperature control base 104 to reduce the temperature of the dielectric 102 and a substrate W disposed thereon. Conversely, the fluid may be used to increase the temperature of the temperature control base 104 and heat the dielectric 102 and a substrate W disposed thereon. In other embodiments, a resistive heater (not shown) may be disposed within the temperature control base. In some cases, heat from the resistive heater, combined with heat transfer from the temperature control base 104 to the fluid, may be used to maintain the dielectric 102 or the substrate W at a set temperature.

[0011] The flow aperture 112 is disposed within the substrate support 100. As shown in FIG. 1 , the flow aperture 112 is formed to penetrate the dielectric 102, the bonding layer 106, and the temperature control base 104. In this configuration, gas introduced through the flow aperture 112 is present in the region between the side of the substrate W facing the dielectric 102 and the opposing surface of the dielectric 102. The gas is maintained at a pressure sufficient to allow the gas to act as a thermal conduction path between the substrate W and the dielectric 102. A gas source (not shown) is connected to the flow aperture 112. During processing, a gas such as helium flows from the gas source and is delivered through the flow aperture 112 to the underside of the substrate W (this side is not exposed to the processing area of the chamber). Some gases are known to degrade the bonding layer 106 exposed to the gas at the flow aperture 112.

[0012] 2A and 2B are cross-sectional schematic diagrams of the dielectric 102, the temperature control base 104, and the intermediate bonding layer 106. In FIGS. 2A-2B, the substrate support 100 includes the dielectric 102 and the temperature control base 104 similar to those in FIG. 1. Here, the bonding layer 106 includes two-part layers 106a and 106b. In the embodiment of FIGS. 2A-2B, the bonding layers 106a and 106b include multiple sheets of bonding material. The bonding layers 106a and 106b include an organic material (e.g., silicone, acrylic, perfluoropolymer, or a combination thereof), although other materials are contemplated. In some embodiments, the bonding layer 306 additionally includes an inorganic material (e.g., alumina, aluminum nitride, or silicon carbide) to enhance certain properties of the bonding layer 306 (e.g., thermal conductivity). The bonding layer 106a is disposed on the surface 208 of the dielectric 102. The bonding layer 106b is disposed on the opposing surface 210 of the temperature-controlled base 104. The bonding layers 106a, 106b are adhered to the dielectric 102 and the temperature-controlled base 104, respectively (FIG. 2A), before forming the completed bonding layer 106 (FIG. 2B), thereby improving the bonding strength of the bonding material and increasing the thickness uniformity of the bonding material. The final bonding layer 106 is formed by a curing process. The bonding layer 106 may have a thickness ranging from approximately 100 micrometers to 800 micrometers, and may be made thicker or thinner as needed to achieve desired material properties, bond strength, and thermal conductivity characteristics between the dielectric 102 and the temperature-controlled base 104. While FIGS. 2A-2B illustrate the use of a sheet of bonding material, it is understood that any method capable of forming a bonding layer (e.g., casting, pasting, spraying, or molding the bonding material on the surfaces of the dielectric 102 and the temperature-controlled base 104, respectively) may be used. Additionally, a different number of layers may be used to form bonding layer 106 .

[0013] The flow aperture 112 penetrates the substrate support 100. For simplicity, one flow aperture is shown in FIGS. 2A-2B, but it is understood that multiple apertures may be used. The flow aperture 112 is formed through the dielectric 102, the bonding layer 106, and the temperature control base 104. The portion of the flow aperture 112 disposed within the temperature control base 104 comprises two sections. The first section extends inward from a surface 210 facing the dielectric 102 toward the center of the body of the temperature control base 104. The first section is a counterbore that partially penetrates the temperature control base 104 and forms a cylindrical recess 212. The second section extends from the recess 212 through the remainder of the temperature control base 104 and has a circular cross section. The first and second sections each have a diameter such that the diameter of the second section is smaller than the diameter of the first section, as shown in FIGS. 2A-2B. The bonding layer 106 is disposed adjacent to the surface 210 of the temperature control base 104. An opening is formed through each of bonding layers 106a, 106b, and these openings are aligned with the center of recess 212, forming an aperture through each bonding layer 106a, 106b. Opening 214 in bonding layer 106b has a diameter equal to or greater than the diameter of recess 212. Opening 216 in bonding layer 106a has a diameter smaller than opening 214. In some embodiments, opening 216 may have a diameter substantially equal to the diameter of recess 212. The openings 214, 216 through bonding layers 106a form a "stepped bond" when bonding layers 106a, 106b are assembled as shown in FIG. 2B .

[0014] A series of vanes 218 are formed within the dielectric 102 and are configured to align with the recesses 212 and openings 214, 216 to partially define the flow apertures 112. While FIGS. 2A-2B show two vanes defining three passages with adjacent sidewalls of the dielectric 102, any applicable number of vanes may be implemented in embodiments herein. Plugs 220 are optionally disposed within the dielectric 102 and align with the flow apertures 112. The plugs 220 are formed from a porous material, such as a ceramic, which may be alumina or zirconia. The plugs 220 have porosity (e.g., a porosity ranging from 10% to 80%) to allow passage of gas from the recesses 212 through the openings 214, 216 to the passages between the vanes 218, providing fluid communication with the area between the substrate W and the dielectric 102 when supported on the dielectric 102. Furthermore, the plug 220 prevents particles, ionized particles, or ionized gases from passing from the processing area through the passage between the vanes 218 and into the gas volume area defined by the openings 214, 216 when the substrate W is not on the dielectric 102.

[0015] 2A-2B advantageously enhances the uniformity of the bonding layer by forming two parts and then forming the completed bonding layer. The enhanced uniformity of the bonding material can enhance the bonding material's resistance to degradation due to exposure to process gases. Furthermore, the bond between the dielectric and the temperature control base is consistent throughout the bonding layer, preventing localized delamination due to stresses caused by thermal expansion of the temperature control base and / or the dielectric.

[0016] FIG. 3 shows a schematic cross-section of a substrate support 100 similar to that of FIGS. 1 and 2A-2B. The substrate support 100 of FIG. 3 includes the same components as those of FIGS. 1-2B, which share the same reference numerals and will not be described for brevity. The bonding layer 306 is disposed between the dielectric 102 and the temperature control base 104 and secures the dielectric 102 and the temperature control base 104 together. In the embodiment of FIG. 3, a single sheet of bonding material is used. However, other methods of applying the bonding material (e.g., casting, pasting, spraying, or molding, or using multiple layers of the sheet material) are understood. The bonding layer 306 includes an organic material (e.g., silicone, acrylic, perfluoropolymer, or a combination thereof), although other materials capable of forming a bond are contemplated. In some embodiments, the bonding layer 306 additionally includes an inorganic material (e.g., alumina, aluminum nitride, or silicon carbide) to enhance certain properties of the bonding layer 306 (e.g., thermal conductivity). An annular opening 302 is formed through the bonding layer 306 and is configured to align with the cylindrical recess 212 and the vane 218. The recess 212 and the vane 218, in combination with the annular opening 302, partially define the flow aperture 112. Again, while one flow aperture 112 is shown in FIG. 3 , any number of applicable apertures may be used. The diameter of the opening 302 is smaller than the diameter of the cylindrical recess 212, thereby positioning the edge of the bonding layer 306 above the recess 212 to form a shoulder. The shoulder and opening 302 act as a choke for gas flow to the optional vane 218 or plug 220. The opening 302 also has a smaller diameter than the plug 220, thereby allowing the bonding layer 306 to extend below the plug 220, as shown in FIG. 3 . Here, plug 220 is again used to prevent particles, ionized material particles, or ionized gases from the processing environment from reaching the bonding material when no substrate W is present on dielectric 102. By extending bonding layer 306 above recess 212, the surface area of temperature control base 104 exposed to corrosive processing gases is reduced, thereby significantly reducing corrosion of the metallic temperature control base 104.

[0017] FIG. 4 shows a substrate support 100 similar to that of FIGS. 1-3, with identical components sharing the same reference numerals. Again, for brevity, identical components will not be described. A bonding layer 406 is disposed between and secures the dielectric 102 and the temperature control base 104 together. While one flow aperture 112 is shown disposed within the substrate support 100, any applicable number may be used. An annular opening 414 is formed through the bonding layer 406 and partially defines the flow aperture 112. The opening 414 has a diameter substantially larger than the cylindrical recess 212. A seal 404, such as an O-ring, is optionally disposed within the expanded diameter of the opening 414. The seal 404 functions to seal the bonding layer 406 against gas flowing within the flow aperture 112. The seal 404 comprises a material capable of withstanding degradation due to gas chemistry. In one embodiment, the seal 404 comprises a polymer (e.g., a perfluoropolymer (e.g., Viton® or XPE), polytetrafluoroethylene (PTFE), or silicone). Other materials, such as additional petroleum-based polymers, are also contemplated. Any material suitable for contact with process gases flowing through the flow aperture 112 may be used.

[0018] A plug 420, similar to the plug 220 of FIGS. 2A-3, is optionally positioned within the dielectric 102 adjacent to the vane 218. The plug 420 and the vane 218 may be integral. The plug 420 comprises a porous material, such as ceramic. Its porosity ranges, for example, from 10% to 80%, thereby allowing gas to flow through the plug 420 and into the passage defined by the vane 218 and the adjacent sidewall of the dielectric 102. Like the plug 220, the plug 420 is used to prevent ionized material particles and ionized gas from reaching the bonding material from the processing environment when the substrate W is not present on the dielectric 102. The plug 420 is configured to receive a ring 408. The ring 408 is positioned adjacent to the seal 404 and is in contact with both the seal 404 and the plug 402. The ring 408 may comprise a metal or ceramic material. The ring 408 provides an improved sealing surface for the seal 404. The seal 404 interfaces with the ring 408 to form a first seal point. Opposite the ring 408, the seal 404 interfaces with the temperature control base 104 to form a second seal point. The first and second seal points prevent gas from bypassing the seal 404 and isolate the bonding layer 406 from the gas within the flow aperture 112. Embodiments herein provide an improved seal that protects the bonding layer 406 from process gases, thereby increasing the life and durability of the bonding material.

[0019] In some embodiments, the bonding material of the bonding layer 406 can be selected to enhance one or more desired properties (e.g., heat transfer or high-temperature adhesion). Conversely, some materials that have desirable properties may be less resistant to degradation caused by exposure to process gases within the flow aperture 112. With the seal 404 and ring 408 shown in FIG. 4 , a less resistant material can be selected for the bonding material because the seal 404 isolates the bonding layer 406 from the process gases. A second seal (not shown) may be disposed around the outer periphery of the bonding layer 406, thereby encapsulating the bonding layer 406 in combination with the seal 404, dielectric 102, and temperature control base 104. Thus, the substrate support 100 can have a bonding layer with desirable properties without reducing the life and durability of the bonding layer.

[0020] It is understood that the embodiments disclosed herein are not limited to electrostatic chucks. The embodiments can be implemented in any configuration using a bonding layer. Furthermore, it is understood that the exemplary geometries disclosed herein do not limit the scope of the embodiments. Other geometries of flow apertures and objects are contemplated.

[0021] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be made without departing from the basic scope thereof, which scope is defined by the following claims.

Claims

[Claim 1] a first body having a flow aperture therethrough; a second body having a flow aperture therethrough; a bonding layer disposed between the first body and the second body, a first bonding layer having a first opening therethrough; A bonding layer structure comprising a bonding layer having a second bonding layer having a second opening therethrough, the second opening having a diameter greater than the diameter of the first opening.

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