Patent Publication Number: US-11651987-B2

Title: Substrate support carrier with improved bond layer protection

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Non-Provisional Application Ser. No. 16/857,082, filed on Apr. 23, 2020, which claims benefit of U.S. Provisional Patent Application 62/852,843, filed on May 24, 2019, each of which are herein incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Field 
     The embodiments of the disclosure generally relate to a substrate support pedestal having a protected bond layer for use in a substrate process chamber. 
     Description of the Related Art 
     Substrate support pedestals are widely used to support substrates within semiconductor processing systems during substrate processing. The substrate support pedestals generally include an electrostatic chuck bonded to a cooling base with a bond layer. An electrostatic chuck generally includes one or more embedded electrodes which are driven to an electrical potential to hold a substrate against the electrostatic chuck during processing. The cooling base typically includes one or more cooling channels and aids in controlling the temperature of the substrate during processing. Further, the electrostatic chuck may include one or more gas flow passages that allow a gas to flow between the electrostatic chuck and the substrate to assist in controlling the temperature of the substrate during process. The gas fills the area between the electrostatic chuck and the substrate, enhancing the heat transfer rate between the substrate and the substrate support. However, when a substrate is not present, the gas flow passages also provide a path for the process gases to flow into the area between the electrostatic chuck and the cooling base where the bond layer is located. Consequently, the bond layer is eroded by the process gases. 
     The erosion of bond layer is problematic for at least two reasons. First, material eroded from bond layer is a process contaminant that produces defects and reduces product yields. Secondly, as the bond layer is eroded, the local rate heat transfer between the electrostatic chuck and cooling base changes, thereby creating undesirable temperature non-uniformities on the substrate and process drift. 
     Therefore, there is a need for an improved substrate support pedestal. 
     SUMMARY OF THE DISCLOSURE 
     In one example, a substrate support pedestal is provided that includes an electrostatic chuck, a cooling base, a gas flow passage, a porous plug, and a sealing member. The electrostatic chuck comprises body having a cavity. The cooling base is coupled to the electrostatic chuck via a bond layer. The gas flow passage is formed between a top surface of the electrostatic chuck and a bottom surface of the cooling base. The gas flow passage further comprises the cavity. The porous plug is positioned within the cavity to control the flow of gas through the gas flow passage. The sealing member is positioned in a groove formed in the cooling base and configured to form a seal between the cooling base and one or both of the porous plug and the body of the electrostatic chuck 
     In one example, an electrostatic chuck has a body comprising a top surface, a cavity, a gas flow passage, and a porous plug. The gas flow passage is formed between the top surface and the cavity. The porous plug is positioned within the cavity. A sealing member is positioned adjacent to the porous plug and is configured to form one or more of a radial seal between the porous plug and the cavity and an axial seal between the porous plug and a cooling base bonded to the electrostatic chuck. 
     In one example, a substrate support pedestal is provided that includes an electrostatic chuck, a cooling base, a gas flow passage, a porous plug, and a sealing member. The electrostatic chuck having a body comprising a cavity. The cooling base is coupled to the electrostatic chuck via a bond layer. The gas flow passage is formed between a top surface of the electrostatic chuck and a bottom surface of the cooling base. The gas flow passage further includes the cavity. The porous plug is positioned within the cavity. The sealing member is positioned adjacent to the porous plug and is configured to form one or more of a radial seal between the porous plug and the cavity and an axial seal between the porous plug and the cooling base. 
     In one example, a process chamber comprises a chamber body, an electrostatic chuck, a cooling base, a gas flow passage, a porous plug and a sealing member. The chamber body has a processing volume. The electrostatic chuck is disposed in the processing volume and has a top surface configured to support a substrate during processing. The electrostatic chuck further comprises a bottom surface and a cavity. The cooling base is coupled to the electrostatic chuck via a bond layer. The gas flow passage is formed between the top surface of the electrostatic chuck and a bottom surface of the cooling base. Further, the gas flow passage passes through the cavity. The porous plug is positioned within the cavity. The sealing member is positioned adjacent to the porous plug and is configured to form one or more of a radial seal between the porous plug and the cavity and an axial seal between the porous plug and the cooling base. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       So that the manner in which the above recited features of the present disclosure are attained and can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIG.  1    depicts a schematic of a process chamber having a substrate support pedestal, according to one or more embodiments. 
         FIG.  2    depicts a partial sectional view of the substrate support pedestal, according to one or more embodiments. 
         FIGS.  3 ,  4 ,  5 ,  6 ,  7 ,  8  and  9    are partial sectional views of the substrate support pedestal, according to one or more embodiments. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, wherever possible, to designate identical elements that are common to the figures. 
     DETAILED DESCRIPTION 
     The systems and methods discussed herein employ substrate support pedestals that have a cooling base and electrostatic chuck bonded together via a bond layer. A porous plug is positioned in a gas flow passage formed in the cooling base and the electrostatic chuck. The restriction of the porous plug protects the bond layer from the process gases utilized during substrate processing. Advantageously, the following embodiments discuss improved techniques for securing the porous plug within the gas flow passage to prevent degradation of the bond layer through the utilization of a radial seal that substantially prevents gas flowing around the porous plug. 
       FIG.  1    depicts a schematic diagram of a process chamber  100 , according to one or more embodiments. The process chamber  100  includes at least an inductive coil antenna segment  112 A and a conductive coil antenna segment  112 B, both positioned exterior to a dielectric, ceiling  120 . The inductive coil antenna segment  112 A and the conductive coil antenna segment  1128  are each coupled to a radio-frequency (RF) source  118  that produces an RF signal. The RF source  118  is coupled to the inductive coil antenna segment  112 A and to the conductive coil antenna segment  1128  through a matching network  119 . Process chamber  100  also includes a substrate support pedestal  116  that is coupled to an RF source  122  that produces an RF signal. The RF source  122  is coupled to the substrate support pedestal  116  through a matching network  124 . The process chamber  100  also includes a chamber wall  130  that is conductive and connected to an electrical ground  134 . 
     A controller  140  comprising a central processing unit (CPU)  144 , a memory  142 , and support circuits  146 . The controller  140  is coupled to the various components of the process chamber  100  to facilitate control of the substrate processing process. 
     In operation, the semiconductor substrate  114  is placed on the substrate support pedestal  116  and gaseous components are supplied from a gas panel  138  to the process chamber  100  through entry ports  126  to form a gaseous mixture in a processing volume  150  of the process chamber  100 . The gaseous mixture in the processing volume  150  is ignited into a plasma in the process chamber  100  by applying RF power from the RF sources  118 ,  122  respectively to the inductive coil antenna segment  112 A, the conductive coil antenna segment  1128  and to the substrate support pedestal  116 . Additionally, chemically reactive ions are released from the plasma and strike the substrate; thereby removing exposed material from the substrate&#39;s surface. 
     The pressure within the interior of the process chamber  100  is controlled using a throttle valve  127  situated between the process chamber  100  and a vacuum pump  136 . The temperature at the surface of the chamber walls  130  is controlled using liquid-containing conduits (not shown) that are located in the chamber walls  130  of the process chamber  100 . 
     The substrate support pedestal  116  comprises an electrostatic chuck  102  disposed on a cooling base  104 . The substrate support pedestal  116  is generally supported above the bottom of the process chamber  100  by a shaft  107  coupled to the cooling base  104 . The substrate support pedestal  116  is fastened to the shaft  107  such that the substrate support pedestal  116  can be removed from the shaft  107 , refurbished, and re-fastened to the shaft  107 . The shaft  107  is sealed to the cooling base  104  to isolate various conduits and electrical leads disposed therein from the process environment within the process chamber  100 . Alternatively, the electrostatic chuck  102  and cooling base  104  may be disposed on an insulating plate that is attached to a ground plate or chassis. Further, the ground plate may be attached to one or more of the chamber walls  130 . 
     The temperature of the semiconductor substrate  114  is controlled by stabilizing the temperature of the electrostatic chuck  102 . For example, a backside gas (e.g., helium or other gas) may be provided by a gas source  148  to a plenum defined between the semiconductor substrate  114  and a support surface  106  of the electrostatic chuck  102 . The backside gas is used to facilitate heat transfer between the semiconductor substrate  114  and the substrate support pedestal  116  to control the temperature of the substrate  114  during processing. The electrostatic chuck  102  may include one or more heaters. For example, the heaters may be electrical heaters or the like. 
       FIG.  2    depicts a vertical cross-sectional view of a portion of the substrate support pedestal  116  depicted in  FIG.  1   , according to one or more embodiments. As is discussed above the substrate support pedestal  116  has the cooling base  104  secured to the electrostatic chuck  102 . In the example depicted in  FIG.  2   , the cooling base  104  is secured to the electrostatic chuck  102  by a bond layer  204 . 
     The bond layer  204  comprises one or more materials such as an acrylic or silicon-based adhesive, epoxy, neoprene based adhesive, an optically clear adhesive such as a clear acrylic adhesive, or other suitable adhesive materials. 
     The cooling base  104  is generally fabricated from a metallic material such as stainless steel, aluminum, aluminum alloys, among other suitable materials. Further, the cooling base  104  includes one or more cooling channels  212  disposed therein that circulate a heat transfer fluid to maintain thermal control of the substrate support pedestal  116  and the substrate  114 . 
     The electrostatic chuck  102  is generally circular in form but may alternatively comprise other geometries to accommodate non-circular substrates. For example, the electrostatic chuck  102  may comprise a square or rectangular substrate when used in processing display glass, such as such as glass for flat panels displays. The electrostatic chuck  102  generally includes a body  206  including one or more electrodes  208 . The electrodes  208  are comprised of an electrically conductive material such as copper, graphite, tungsten, molybdenum and the like. Various embodiments of electrode structures include, but are not limited to, a pair of coplanar D-shaped electrodes, coplanar interdigital electrodes, a plurality of coaxial annular electrodes, a singular, circular electrode or other structure. The electrodes  208  are coupled to a power supply  125  by a feed through  209  disposed in the substrate support pedestal  116 . The power supply  125  may drive the electrode  208  with a positive or negative voltage. For example, the power supply  125  may drive the electrode  208  with a voltage of about −1000 volts or a voltage of about 2500 volts. Alternatively, other negative voltages or other positive voltages may be utilized. 
     The body  206  of the electrostatic chuck  102  may be fabricated from a ceramic material. For example, the body  206  of the electrostatic chuck  102  may be fabricated from a low resistivity ceramic material (i.e., a material having a resistivity between about 1×E 9  to about 1×E 11  ohm-cm). Examples of low resistivity materials include doped ceramics such as alumina doped with titanium oxide or chromium oxide, doped aluminum oxide, doped boron-nitride and the like. Other materials of comparable resistivity, for example, aluminum nitride, may also be used. Such ceramic materials having relatively low resistivity generally promote a Johnsen-Rahbek attractive force between the substrate and electrostatic chuck  102  when power is applied to the electrodes  208 . Alternatively, a body  206  comprising ceramic materials having a resistivity equal to or greater than 1Ex 11  ohms-cm may also be used. Further, the body  206  of the electrostatic chuck  102  may be fabricated from an aluminum oxide. 
     The support surface  106  of the body  206  includes a plurality of mesas  216  disposed inwards of a seal ring (not shown) formed on the support surface  106 . The seal ring is comprised of the same material comprising the body  206  but may alternatively be comprised of other dielectric materials. The mesas  216  are generally formed from one or more layers of an electrically insulating material having a dielectric constant in the range of about 5 to about 10. Examples of such insulating materials include, but are not limited to, silicon nitride, silicon dioxide, aluminum oxide, tantalum pentoxide, polyimide and the like. Alternatively, the mesas  216  may be formed from the same material as the body  206  and then coated with a high resistivity dielectric film. 
     During operation, an electrical field generated by driving the electrodes  208  holds the substrate  114  on the support surface  106  with a clamping force. The clamping force is greatest at each mesa  216 . Further, the mesas  216  may be positioned and/or sized to achieve a uniform charge distribution across the backside of the substrate. 
     A backside gas (e.g., helium, nitrogen or argon) is introduced to a plenum  280  by the gas source  148  to aid in the control the temperature across the substrate  114  when it is retained by the electrostatic chuck  102 . The plenum  280  is defined between the support surface  106  of the electrostatic chuck  102  and the substrate  114 . Further, the backside gas within the plenum  280  provides a heat transfer medium between the electrostatic chuck  102  and the substrate  114 . The backside gas is generally provided to the plenum  280  through one or more gas flow passages  270  formed through the body  206  and the cooling base  104 . Further, each gas flow passage  270  terminates at a corresponding opening  210  formed through the support surface  106  of the body  206 . 
     The gas flow passage  270  extends from the support surface  106  of the body  206  to a bottom surface  284  of the cooling base  104 . The gas flow passage  270  includes the opening  210  in the electrostatic chuck  102 , an opening  209  in the cooling base  104 , and a cavity  211  formed in the body  206  of the electrostatic chuck  102 . The cavity  211  may have a sectional area, such as a diameter, that is greater than a sectional area of at least one of the opening  210  and the opening  209 . The opening  209  may have a diameter that is greater than, less than or equal to the diameter of the opening  210 . Further, while a single gas flow passage  270  is illustrated in  FIG.  2   , the substrate support pedestal  116  may include multiple gas flow passages. 
     The gas flow passage  270  is coupled to the gas source  148 . Additionally, each of gas flow passage  270  may be coupled to the gas source  148  through a single port  272 . Alternatively, each gas flow passage  270  may be individually coupled to the gas source  148  through separate ports  272 . 
     A porous plug  244  is generally disposed within the gas flow passage  270  (within the cavity  211 ) such that it forms a part of the gas flow passage  270 . The porous plug  244  provides a path for pressurized gas to flow between two surfaces of different electrical potential. For example, the porous plug  244  provides a path for pressurized gas to flow between a first and second surface of the electrostatic chuck  102 , and between a first surface of the electrostatic chuck  102  and a first surface of the cooling base  104 . Further, the porous plug  244  comprises a plurality of small passage ways which reduce the probability that plasma will ignite in the gap  204 A between the electrostatic chuck  102  and the cooling base  104  as compared to a design not including the porous plug  244 . The porous plug  244  is generally comprised of a ceramic material such as aluminum oxide or aluminum nitride. Alternatively, the porous plug  244  may be comprised of other porous materials. Further, the porous plug  244  may have a porosity of about 30 to about 80 percent. Alternatively, the porous plug may have a porosity of less than 30 percent or greater than 80 percent. Additionally, the porous plug  244  abuts a step  250  that defines the top of the cavity  211 . 
     The porous plug  244  has a t-shape. A t-shaped porous plug provides increased gas flow as compared to porous plugs of other shapes and is easier to install into the cavity  211  than porous plugs of other shapes. The porous plug  244  may include a head  251  and a shaft  252 . The head  251  has a diameter  253  and the shaft  252  has a diameter  254 . Further, the diameter  253  is larger than the diameter  254 . Additionally, the head includes bottom surface  255  which meets the shaft  252 . The head  251  further includes surface  256  facing the sidewall  205  of the cavity  211 . Further, the shaft  252  includes a surface  257  facing the sidewall  205  of the cavity  211 . In various embodiments, the porous plug  244  may be positioned within the cavity  211  using various techniques such as press fitting, slip fitting, clearance fitting, pinning, and bonding, among others. For example, the porous plug  244  may be positioned within the cavity such that the surface  256  of the head  251  is in contact with the sidewall  205  or such that there is a gap between the surface  256  of the head  251  and the sidewall  205 . 
     The sealing member  245  is disposed adjacent to the porous plug  244 . The sealing member  245  forms a seal between the surface  257  of the porous plug  244  and the sidewall  205  of the cavity  211 . The sealing member  245  may form at least one of a radial seal between the porous plug  244  and the cavity  211  and an axial seal between the porous plug  244  and the cooling base  104 . Further, the sealing member  245  may secure the porous plug  244  within the cavity  211 . For example, the sealing member  245  may be coupled to at least one of the porous plug  244  and the sidewall  205  of the cavity  211  using various techniques, such as press fitting, pinning, and bonding, among others. The sealing member  245  may mechanically secure the porous plug  244  to the sidewall  205  of the cavity  211 . 
     The sealing member  245  may be comprised of a resilient polymeric material, such as an elastomer. Further, the sealing member  245  may be comprised of one or more of a fluoroelastomer material (e.g., a FKM), a perfluoroelastomer material (e.g., a FFKM), and a highly purity ceramic. The highly purity ceramic may be greater than 99% pure and may be a ceramic paste or a solid suspended in solution. Further, the sealing member  245  may be comprised of a material that is erosion resistive to the process gases. For example, erosion resistive materials do not erode in the presence of process gases. Additionally, or alternatively, the material of the sealing member  245  is selected such that the material does not penetrate the porous plug  244 . The sealing member  245  may be an O-ring, a cylindrical gasket, or other ring-shaped seal. Alternatively, the sealing member  245  may be formed from a material that is applied in one of a liquid, paste and/or gel and changes state to a substantially solid or gel form. Further, the sealing member  245  may be comprised of a substantially non-adhesive material. 
     The bond layer  204  secures the body  206  to the cooling base  104 . Further, a gap  204 A is formed in the bond layer  204  and is part of the gas flow passage  270 . As the material or materials that typically make up the bond layer  204  are susceptible to erosion in the presence of the process gases used during substrate processing, various methods for protecting the bond layer  204  from the process gases have been explored. Advantageously, by employing a sealing member, e.g., the sealing member  245 , which is highly erosion resistive to the process gases, the process gas passing through the porous plug  244  may be prevented. Thus, the life of the bond layer  204  is increased. Additionally, the useful service life of the substrate support pedestal  116  is increased. 
       FIG.  3    is a schematic cross-section of a portion  201  of the substrate support pedestal  116 , according to one or more embodiments. As is described above, the porous plug  244  has the head  251  and the shaft  252 , forming the t-shape of the porous plug  244 . A t-shaped porous plug may provide a better gas flow than porous plugs of other shapes and may be easier to install into the cavity  211  than porous plugs of other shapes. Further, the porous plug  244  prevents the backside gas from flowing into the gap between the electrostatic chuck  102  and the cooling base  104  and negatively affecting (e.g., eroding) the bond layer  204 . 
     The porous plug  244  may extend from a first end  302  of the cavity  211  to a second end  304  of the cavity  211 . For example, the surface  306  of the porous plug  244  may contact the surface  309  of the cavity, and the surface  308  of the porous plug  244  and the surface  307  of the electrostatic chuck  102  may be coplanar, such that the surface  308  does extend into the gap  305  between the electrostatic chuck  102  and the cooling base  104 . Alternatively, the surface  308  may extend into the gap  305  between the electrostatic chuck  102  and the cooling base  104 . Further, the surface  308  may be between the surface  309  and the surface  307 . 
     As is stated above with regard to  FIG.  2   , the porous plug  244  includes the diameter  253  that is greater than the diameter  332  of the opening  210 . Further, the porous plug  244  and the opening  210  are concentric. Additionally, or alternatively, the porous plug  244  and the opening  209  are concentric. 
     The cavity  211  includes a chamfered edge  310  formed where the sidewall  205  meet the bottom surface  307  of the electrostatic chuck  102 . Further, the porous plug  244  may have a chamfered edge where the surface  306  meets the surface  256 . The chamfered edge  310  of the cavity  211  and the chamfered edge  320  of the porous plug  244  aid in the insertion of the porous plug  244  into the cavity  211 . Further, the chamfered edge  310  reduces possible damage that may be caused to the sealing member  245  when the sealing member  245  is inserted into the cavity around the porous plug  244 , or the sealing member  245  expands during substrate processing. 
     The sealing member  245  is adjacent to the porous plug  244 . The sealing member  245  forms a radial seal between the porous plug  244  and the cavity  211 . For example, the sealing member  245  may contact the surface  257  of the porous plug  244  and the sidewall  205  of the cavity  211 , preventing process gases from flowing along the sides of the porous plug  244 . Further, the sealing member  245  may secure the porous plug  244  within the cavity  211 . For example, the sealing member  245  may exert a force on the sidewall  205  of the cavity  211  and the surface  257  of the porous plug  244  such that the porous plug  244  is held within the cavity  211 . Additionally, the sealing member  245  includes surfaces  356  and  357 . One or more of the surfaces  356  and  357  may have a substantially curved shape. The substantially curved shape may be convex or concave. Further, one or more of the surfaces  356  and  357  may have a substantially flat shape. 
     The sealing member  245  may completely reside within the cavity  211  or the sealing member  245  may at least partially extend into the gap  305  between electrostatic chuck  102  and the cooling base  104 . Further, the sealing member  245  may be sized such that the sealing member  245  does not exceed the opening of the cavity  211  defined between the surface  255  of the porous plug  244 , the surface  257  of the shaft  252 , the surface  307  of the electrostatic chuck  102 , and the sidewall  205  of the cavity  211 . Additionally, or alternatively, the bonding layer  204  may extend into the gap  305  such that the bonding layer  204  at least partially contacts the sealing member  245 . 
       FIG.  4    is a schematic cross-section of the portion  201  of the substrate support pedestal  116 , having a different sealing member  445 . As compared to the sealing member  245  of  FIG.  3   , the sealing member  445  of  FIG.  4    forms a radial seal between the surface  257  of the shaft  252  the sidewall  205  of the cavity  211  and an axial seal between the surface  255  of the porous plug  244  and a surface  404  of the cooling base  104 . For example, the sealing member  245  may contact the surface  257  and the surface  255  of the porous plug  244 , the sidewall  205  of the cavity  211  and the surface  404  of the cooling base  104 . The sealing member  445  is positioned adjacent to the porous plug  244 . For example, the sealing member  445  is positioned between the porous plug  244  and the sidewall of the cavity  211 . Further, the sealing member is positioned between the porous plug  244  and the cooling base  104 . Additionally, the sealing member  445  may be formed similar to that of the sealing member  245 . For example, the sealing member  445  may be an O-ring, a cylindrical gasket, or other ring-shaped seal. Further, the sealing member  245  may be formed from a material that is erosion resistive in the presence of the process gases used during substrate processing as are described above with regard to the sealing member  245 . Additionally, the sealing member  445  includes surfaces  456  and  457 . One or more of the surfaces  456  and  457  may have a substantially curved shape. The substantially curved shape may be convex or concave. Further, one or more of the surfaces  456  and  457  may have a substantially flat shape. Further, the bonding layer  204  may at least partially contact the sealing member  445 . 
       FIG.  5    is a schematic cross-section of the portion  201  of the substrate support pedestal  116 , having a different sealing member  545  and porous plug  544 . The porous plug  544  is configured similar to that of the porous plug  244  of  FIGS.  2  and  3   , however, the instead of comprising a t-shape, the porous plug  544  comprises a cylindrical shape. The sealing member  545  is positioned adjacent to the porous plug  544 . For example, the sealing member  545  is positioned between the porous plug  544  and the sidewall of the cavity  211 . Further, the sealing member may be positioned between the surface  309  of the cavity  211  and the cooling base  104 . The porous plug  544  has diameter  530 , top surface  506 , bottom surface  508  and surface  550 . The top surface  506  contacts the surface  309  of the cavity  211 . Further, the surface  508  may be recessed within the cavity  211 , coplanar with surface  307  of the electrostatic chuck  102 , or extend into the gap  305  formed between the surface  307  of the electrostatic chuck and the surface  404  of the cooling base  104 . The diameter  530  of the porous plug  544  is greater than the diameter  532  of the opening  210 . 
     The sealing member  545  may be formed similar to that of the sealing member  245 . For example, the sealing member  545  may be an O-ring, a cylindrical gasket, or other ring-shaped seal. Further, the sealing member  545  may be formed from a material that is erosion resistive in the presence of the process gases used during substrate processing as are described above with regard to the sealing member  245 . The sealing member  545  forms a radial seal between the surface  550  of the porous plug  544  and the sidewall  205  of the cavity  211 . For example, the sealing member  545  contacts the surface  550  of the porous plug  544  and the sidewall  205  of the cavity  211 , such as the sealing member  445  illustrated in  FIG.  4   . Additionally, the sealing member  545  may form an axial seal between the surface  309  of the cavity  211  and the surface  404  of the cooling base  104 . For example, the sealing member  545  may contact the surface  309  of the cavity  211  and contact the surface  404  of the cooling base  104 . The sealing member  545  includes surfaces  556  and  557 . One or more of the surfaces  556  and  557  may have a substantially curved shape. The substantially curved shape may be convex or concave. One or more of the surfaces  556  and  557  may have a substantially flat shape. Further, the bonding layer  204  may protrude into the gap  305  such that the bonding layer  204  at least partially contacts the sealing member  545 . 
       FIG.  6    is a schematic cross-section of the portion  201  of the substrate support pedestal  116  having a different sealing member  645 , according to one or more embodiments. As compared to the sealing member  245  of  FIG.  3   , the sealing member  645  of  FIG.  6    is formed from a material applied in a liquid, paste or gel form, that changes state to a substantially solid or gel form. For example, the sealing member  645  may be formed from one of a fluoroelastomer material, a perfluoroelastomer material, and a high purity ceramic potting material, among others, that can be flowed or otherwise disposed in the cavity  211  around the porous plug  244  in a liquid or viscous state, which changes state to a more solid and substantially immobile form. The sealing member  645  is disposed adjacent to the porous plug  244  such that the material is disposed between the surface  257  and the surface  255  of the porous plug  244  and the sidewall  205  of the cavity  211 . Further, the material may exposed to a predetermined pressure, temperature, and/or energy source to change the material to a substantially immobile form and generate the sealing member  645 . The temperatures used to change the material to a substantially immobile file may be less than about 300 degrees Celsius. Alternatively, other temperatures may be utilized. Additionally, the sealing member  645  secures the porous plug  244  in the cavity  211 , forming a radial seal between the surface  257  of the porous plug  244  and the sidewall  205  the cavity  211 . Further, the bonding layer  204  may protrude into the gap  305  such that the bonding layer  204  at least partially contacts the sealing member  645 . 
       FIG.  7    is a schematic cross-section of the portion  201  of the substrate support pedestal  116  having a different sealing member  745 , according to one or more embodiments. As compared to the sealing member  545  of  FIG.  5   , the sealing member  745  of  FIG.  7    is formed from a material applied in a liquid, paste or gel form, that changes state to a substantially solid or gel form. For example, the sealing member  745  may be formed from one of a fluoroelastomer material, a perfluoroelastomer material, and a high purity ceramic potting material, among others, that can be flowed or otherwise disposed in the cavity  211  around the porous plug  544  in a liquid or viscous state, which changes state to a more solid and substantially immobile form. The material may be disposed between the surface  550  of the porous plug  544  and the sidewall  205  and the surface  309  of the cavity  211 . Further, the material is exposed to a predetermined pressure, temperature, and/or energy source to change the material to a substantially immobile form and generate the sealing member  745 . Additionally, the sealing member  745  contacts the surface  550  of the porous plug  544  and the surface  309  and the sidewall  205  of the cavity  211 , securing the porous plug  544  in the cavity  211 . Further, the sealing member  745  forms a radial seal between the surface  550  of the porous plug  544  and the sidewall  205  the cavity  211 . Further, the bonding layer  204  may protrude into the gap  305  such that the bonding layer  204  at least partially contacts the sealing member  745 . 
       FIG.  8    is a schematic cross-section of the portion  201  of the substrate support pedestal  116 , having a different porous plug  844  and a different sealing member  845  as compared to the embodiment of  FIG.  2   . For example, as compared to the porous plug  244  of  FIG.  2   , the porous plug  844  comprises a cylindrical shape. Further, as compared to the porous plug  544  of  FIG.  5   , the diameter  830  of the porous plug  844  is greater than the diameter  530  of the porous plug  544  such that the porous plug  844  fills more of the cavity  211  than porous plug  544 . The diameter of the porous plug  844  is greater than the diameter  832  of the opening  210 . The top surface  806  contacts the surface  309  of the cavity  211 . The surface  808  may be coplanar with surface  307  of the electrostatic chuck  102 . The porous plug  844  may have a chamfered edge along the surface  806  similar to that of the porous plug  244  of  FIG.  3   . 
     The sealing member  845  may be formed similar to that of the sealing member  245 . For example, the sealing member  845  may be an O-ring, a cylindrical gasket, or other ring-shaped seal. Further, the sealing member  845  may be formed from a material that is erosion resistive in the presence of the process gases used during substrate processing as are described above with regard to the sealing member  245 . The sealing member  845  forms an axial seal between the surface  808  of the porous plug  844 , the surface  307  of the electrostatic chuck  102  and the surface  809  of the cooling base  104 . For example, the sealing member  845  contacts the surface  809  of the porous plug  844  and the surface  307  of the electrostatic chuck  102 . Further, the sealing member  845  contacts the surface  809  of the cooling base  104 . 
     The sealing member  845  is positioned adjacent to the porous plug  844 . For example, the sealing member  845  is positioned between the porous plug  844  and the cooling base  104 . 
     The cooling base  104  may include a groove  810 . The surface  809  of the cooling base  104  forms the bottom of the groove  810 . The sealing member  845  is positioned in the groove  810  and between the cooling base  104  and the electrostatic chuck  102 . The groove  810  at least partially overlaps a portion of the cavity  211  and a portion of the electrostatic chuck  102 , thus allowing the groove  810  to effectively position the sealing member  845  across and sealing the gap defined between the porous plug  844  and the electrostatic chuck  102 . As compared to embodiments that do not include the groove  810 , the groove  810  allows for a larger cross-section seal without increasing the thickness of the bond layer. Further, the groove  810  decreases the effects of manufacturing tolerances and allows for sealing over wider range of temperatures. In one or more embodiments, the cooling base  104  does not include the groove  810  and the sealing member  845  is in contact with the surface  809  in an area overlapping with a portion of the electrostatic chuck  102  and the cavity  211 . 
     The sealing member  845  may secure the porous plug  844  within the cavity  211 . For example, the sealing member  845  may exert a force on the surface  808  of the porous plug  844  and the surface  809  of the cooling base  104  such that the porous plug  844  is held within the cavity  211 . 
     The sealing member  845  includes surfaces  856  and  857 . One or more of the surfaces  856  and  857  may have a substantially curved shape. The substantially curved shape may be convex or concave. Further, one or more of the surfaces  856  and  857  may have a substantially flat shape. Further, the bonding layer  204  may at least partially contact the sealing member  845 . 
       FIG.  9    is a schematic cross-section of the portion  201  of the substrate support pedestal  116 , having a porous plug  944  and a sealing member  845 , according to one or more embodiments. The sealing member  845  is described in greater detail with regard to  FIG.  8   . As is described with regard to  FIG.  8   , the cooling base  104  includes groove  810  at least a portion of the sealing member  845  is positioned with the groove  810 . 
     As compared to the porous plug  844  of the embodiment of  FIG.  8   , the porous plug  944  includes a surface  908  that extends into the gap  305  between the electrostatic chuck  102  and the cooling base  104 . The diameter  931  of the portion of the porous plug  944  that extends into the gap  305  is less than the diameter  930  of the portion of the porous plug  944  that is positioned within the cavity  211 . The diameter  930  is greater than the diameter  832  of the opening  210 . Alternatively, the diameter  930  is less than or equal to the diameter  832 . Further, the top surface  906  of the porous plug  944  contacts the surface  309  of the cavity  211 . The porous plug  944  may have a chamfered edge along the surface  906  similar to that of the porous plug  244  of  FIG.  3   . 
     The sealing member  845  is positioned adjacent to the porous plug  944 . For example, the sealing member  845  is positioned between the porous plug  944  and the cooling base  104 . The sealing member  845  contacts the surface  307  of the electrostatic chuck  102 , the surface  907  of the porous plug  944 , and the surface  809  of the cooling base  104 , forming an axial seal between the electrostatic chuck  102  and the cooling base  104 . The sealing member  845  may secure the porous plug  944  within the cavity  211 . For example, the sealing member  845  may exert a force on the surface  907  of the porous plug  944  and the surface  809  of the cooling base  104  such that the porous plug  944  is held within the cavity  211 . Further, the sealing member  845  may contact the surface  909  of the porous plug  944 . 
     The sealing members and porous plugs described herein are suitable for use in substrate support pedestals for protecting the bond layer that bonds the cooling base with the electrostatic chuck from the process gases. Advantageously, protecting the bond layer from the process gases reduces erosion of the bond layer, and maintaining a substantially uniform temperature on a substrate. For example, sealing members that are erosion resistive to the process gases may be utilized to form a radial seal and/or vertical seal between porous plugs of the electrostatic chuck. Such sealing members prevent the flow of process gases into the gap between the electrostatic chuck and the cooling base, and reduce the erosion of the bond layer. Accordingly, a substantially uniform thermal transfer between the cooling base and the electrostatic chuck and a uniform temperature on the substrate is maintained. 
     While the foregoing is directed to embodiments described herein, other and further embodiments may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.