Gap pumping of substrate support to prevent glow discharge and ignition

Abstract

An embodiment of a substrate support for use in a substrate processing chamber is provided herein. In some embodiments, the substrate support for use in a substrate processing chamber includes a pedestal having a first surface configured to support a substrate and a second surface opposite the first surface, a plurality of substrate lift pins extending through the pedestal, a plurality of first gaps being disposed between the plurality of substrate lift pins and respective ones of a plurality of substrate lift pin openings of the pedestal, and a vacuum line extending from the plurality of substrate lift pin openings and configured to pump down the plurality of substrate lift pin openings.

Description

[Technical field]

[0001]

[0001] Embodiments of the present disclosure generally relate to substrate processing equipment. [Background technology]

[0002]

[0002] A substrate processing system typically includes a process chamber for performing a desired process, such as an etch process, on one or more substrates disposed therein. For example, in an etch process requiring very high aspect ratio holes for forming contacts or deep trenches for laying infrastructure for electrical pathways, RF power may be used to generate a plasma and / or to create a bias voltage on the substrate being processed to attract ions from the bulk plasma.

[0003]

[0003] A substrate support is disposed in a substrate processing chamber and is configured to support a substrate during processing. However, gaps or cavities in the substrate support that are not under vacuum pressure may be susceptible to glow discharge and lighting up when exposed to a plasma or when a sufficiently high local electric field exists in the gap / cavity. Therefore, the present inventors have provided an embodiment of an improved substrate support. Summary of the Invention

[0004]

[0004] Embodiments of a substrate support for use in a substrate processing chamber are provided herein. In some embodiments, the substrate support for use in a substrate processing chamber includes a pedestal having a first surface configured to support a substrate and a second surface opposite the first surface, a plurality of substrate lift pins extending through the pedestal, a plurality of first gaps being disposed between the plurality of substrate lift pins and respective ones of a plurality of substrate lift pin openings of the pedestal, and a vacuum line extending from the plurality of substrate lift pin openings and configured to pump down the plurality of substrate lift pin openings.

[0005]

[0005] In some embodiments, a process chamber for processing a substrate includes a chamber body defining a processing region therein, a substrate support disposed in the chamber body and having an upper surface exposed to the processing region, the substrate support including a pedestal having a first surface configured to support a substrate and a second surface opposite the first surface, a plurality of substrate lift pins extending through the pedestal, the plurality of first gaps being disposed between the plurality of substrate lift pins and respective ones of a plurality of substrate lift pin openings in the pedestal, and a vacuum pump coupled to each of the plurality of first gaps via a vacuum line extending to the plurality of substrate lift pin openings, the vacuum pump configured to pump down the plurality of first gaps without pumping down the processing region.

[0006]

[0006] In some embodiments, a process chamber for processing a substrate includes a chamber body defining a processing region therein, a substrate support disposed in the chamber body and having an upper surface exposed to the processing region, the substrate support including a pedestal having a dielectric plate including an electrode and a cooling plate coupled to the dielectric plate, a plurality of substrate lift pins extending through the dielectric plate and through the cooling plate, a plurality of first gaps being disposed between the plurality of substrate lift pins and respective ones of a plurality of substrate lift pin openings in the dielectric plate and the cooling plate, a vacuum pump coupled to each of the plurality of first gaps and configured to pump down the plurality of first gaps to a first pressure, and a second vacuum pump coupled to the chamber body and configured to pump down the processing region to a process pressure, the first pressure being less than the process pressure.

[0007]

[0007] In some embodiments, a method for processing a substrate includes pumping down a processing region of a process chamber to a process pressure and pumping down a number of first gaps disposed around a number of substrate lift pins to a first pressure that is less than the process pressure.

[0008]

[0008] Other further embodiments of the present disclosure are described below.

[0009]

[0009] The embodiments of the present disclosure summarized above and described in more detail below can be understood by reference to the exemplary embodiments of the present disclosure illustrated in the accompanying drawings. However, the accompanying drawings merely illustrate typical embodiments of the present disclosure and therefore should not be considered as limiting the scope, as the present disclosure may admit of other equally effective embodiments. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional side view illustrating a process chamber in accordance with at least some embodiments of the present disclosure. [Diagram 2] 1 is a schematic cross-sectional side view illustrating a substrate support in accordance with at least some embodiments of the present disclosure. [Diagram 3] FIG. 2 is a cross-sectional side view of a portion of a substrate support in accordance with at least some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011]

[0013] To facilitate understanding, the same reference numbers have been used, wherever possible, to designate identical elements common to the drawings. The drawings are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further detail.

[0012]

[0014] An embodiment of a substrate support having a dedicated pump for gap pumping to prevent glow discharge and lighting is provided herein. The substrate support is generally disposed in a process chamber, with a top surface of the substrate support exposed to a processing region. To advantageously prevent gas breakdown, dedicated pumps may be disposed in the substrate support and coupled to various cavities or gaps, which may be configured to pump down the various cavities, for example, separate from pumps configured to pump down the processing region of the process chamber. The cavities may be gaps between various moving parts of the substrate support, gaps to accommodate thermal expansion between various parts of the substrate support, etc. For example, the cavity may be the gap between the lift pin and the lift pin opening. In another example, the cavity may be the gap between the powered electrode and the insulator surrounding the powered electrode. A dedicated gap pumping pump may advantageously achieve a lower pressure in the cavity than can be achieved using any pump used to evacuate process chemicals from the process chamber. A dedicated gap pumping pump can also minimize backflow of process chemicals from the processing region into the cavity compared to using a single pump for both exhaust and gap pumping of process chemicals.

[0013]

[0015] 1 is a schematic cross-sectional side view of a process chamber according to at least some embodiments of the present disclosure. In some embodiments, the plasma processing chamber is an etch processing chamber. However, other types of processing chambers configured for different processes may also be used or modified for use with the substrate support embodiments described herein.

[0014]

[0016] The process chamber, or chamber 100, may be a vacuum chamber suitably adapted to maintain a subatmospheric pressure within an interior region 121 during substrate processing. The chamber 100 includes a chamber body 106 covered by a lid 101 that encloses a processing region 119 located in the upper half of the interior region 121. The chamber 100 may also include one or more shields (not shown) surrounding various chamber components to prevent unwanted reactions between the components and the ionized process materials. The chamber body 106 and the lid 101 may be made of a metal, such as aluminum. The chamber body 106 may be grounded via a bond to ground 115.

[0015]

[0017] A substrate support 124 is disposed within the interior region 121 for supporting and holding a substrate 122, such as a semiconductor wafer or other wafer. The substrate support 124 may generally include a pedestal 150 disposed on the base plate 102. The pedestal 150 includes a first side 146 configured to support a substrate and a second side 149 opposite the first side 146. An upper surface of the substrate support 124 (e.g., the first side 146 of the pedestal 150) is exposed to the processing region 119. In some embodiments, the pedestal includes a dielectric plate 152 disposed on and coupled to the cooling plate 120.

[0016]

[0018] The dielectric plate 152 may include one or more chucking electrodes (see one or more chucking electrodes 210 in FIG. 2 ) configured to electrostatically chuck the substrate 122 to the dielectric plate 152. The one or more chucking electrodes 210 may be monopolar or bipolar. In some embodiments, the substrate support 124 includes one or more process kit components, such as an edge ring 185. In some embodiments, the edge ring 185 is disposed on the pedestal 150 and configured to surround the substrate 122. In some embodiments, the one or more chucking electrodes may also electrostatically chuck the edge ring 185 to the dielectric plate 152.

[0017]

[0019] The cooling plate 120 includes cooling channels 154 configured to circulate a coolant to cool the dielectric plate 152. In some embodiments, the cooling channels 154 are disposed below the dielectric plate 152 and the edge ring 185. In some embodiments, the cooling plate 120 is made of a conductive material, such as aluminum (Al). In some embodiments, the cooling plate 120 is disposed on and coupled to the insulator plate 126. In some embodiments, the insulator plate 126 is disposed on the base plate 102. In some embodiments, the insulator plate 226 is made of aluminum oxide (Al2O3) or a polymer, such as polyphenylene sulfide (PPS).

[0018]

[0020] In some embodiments, the base plate 102 together with the chamber body 106 define a lower region 180 of the chamber 100 below the base plate 102. In some embodiments, the lower region 180 may be at atmospheric pressure during use. Various conduits may extend to the pedestal 150 to provide, for example, backside gases, process gases, fluids, coolants, power, etc. to the pedestal 150. In some embodiments, various conduits may extend through the lower region 180.

[0019]

[0021] In some embodiments, the various conduits may include conduits for the backside gas supply 141, the chucking power supply 140, the RF plasma power supply 170, and the bias power supply 117. The chucking power supply 140 may be coupled to one or more chucking electrodes 210 via a chucking electrode line 143. The RF plasma power supply 170 may alternatively or additionally be disposed in the chamber 100 via the lid 101 or the top of the chamber body 106. In some embodiments, the bias power supply 117 includes one or more RF bias power supplies. In some embodiments, the RF energy provided by the RF plasma power supply 170 may have a frequency of about 400 kHz to greater than 40 MHz. In some embodiments, the RF plasma power supply 170 and the bias power supply 117 are coupled to the pedestal 150 via respective RF match networks (only the RF match network 116 is shown). In some embodiments, the substrate support 124 may alternatively include AC, DC, or RF bias power. In some embodiments, the AC, DC, or RF bias power may be pulsed.

[0020]

[0022] The substrate support 124 includes a plurality of substrate lift pins 168 extending through the substrate support 124 and configured to selectively raise or lower the substrate 122. A plurality of first gaps 174 are disposed between the plurality of substrate lift pins 168 and respective ones of a plurality of substrate lift pin openings 171 of the substrate support 124. In some embodiments, the substrate lift pin openings 171 extend through the dielectric plate 152 and the cooling plate 120. The plurality of substrate lift assemblies 128 are coupled to respective ones of the plurality of substrate lift pins 168 and configured to selectively raise or lower the plurality of substrate lift pins 168. In some embodiments, the plurality of substrate lift pins 168 consists of three lift pins arranged symmetrically around the substrate support 124.

[0021]

[0023] The vacuum pump 160 is coupled to each of the plurality of first gaps 174 via a vacuum line 166 extending from the plurality of substrate lift pin openings 171 to the vacuum pump 160. In some embodiments, the vacuum pump 160 is coupled to each of the plurality of first gaps 174 and configured to pump down the plurality of first gaps 174 to a first pressure. In some embodiments, the first pressure is less than about 10 mTorr. In some embodiments, the first pressure is less than about 1 mTorr. A control valve 145 can be coupled to the vacuum line 166 to control the pressure in the vacuum line 166. In use, the vacuum pump 160 is configured to pump down the plurality of first gaps without pumping down the processing region 119. The vacuum line 166 can include any combination of conduits located outside the substrate support 124 and channels formed through the substrate support 124 into gaps or cavities to be pumped down.

[0022]

[0024] In some embodiments, the substrate support 124 may include a liner 104 disposed about or surrounding the pedestal 150. In some embodiments, one or more of the liner 104 and the base plate 102 are grounded during use. In some embodiments, the liner 104 includes an inner wall 103 and an outer wall 105 that define an annular channel 112 therebetween. In some embodiments, the inner wall 103 and the outer wall 105 are coupled to a bottom plate 107 of the liner 104.

[0023]

[0025] The chamber 100 includes a second vacuum pump 114 fluidly coupled to the processing region 119 for evacuating the processing region 110. In some embodiments, the bottom plate 107 includes one or more pump ports 158 coupled to the second vacuum pump 114 for evacuating the processing region 119. The pressure in the processing region 119 can be adjusted by adjusting a throttle valve of the second vacuum pump 114.

[0024]

[0026] The interior region 121 may include a second region 148 fluidly coupled to the processing region 119. In some embodiments, the one or more pump ports 158 may extend into the second region 148. In some embodiments, the second region 148 is disposed below the substrate support 124 and upstream of the second vacuum pump 114. In some embodiments, the lower region 180 is disposed between the processing region 119 and the second region 148. In some embodiments, the second vacuum pump 114 is coupled to the chamber body 106 adjacent to the second region 148.

[0025]

[0027] In use, a method for processing a substrate includes pumping down the processing region 119 of the process chamber 100 to a process pressure and pumping down the plurality of first gaps 174 disposed around the plurality of substrate lift pins 168 to a first pressure, where the first pressure is less than the process pressure. For example, the second vacuum pump 114 is configured to pump down the processing region 119 to the process pressure and the vacuum pump 160 is configured to pump down the plurality of first gaps 174 to the first pressure.

[0026]

[0028] In some embodiments, the vacuum pump 160 exhausts to the second region 148 via the exhaust line 162. In the above embodiment, the second vacuum pump 114 can exhaust the second region 148 including the contents of the exhaust of the vacuum pump 160. In some embodiments, the second vacuum pump 114 exhausts to the rough line 176. In some embodiments, the vacuum pump 160 exhausts to the rough line 176 via the exhaust line 164 independent of the second vacuum pump 114. For example, the vacuum pump 160 can exhaust to the rough line 176 at a first location 184 and the second vacuum pump 114 can exhaust to the rough line 176 at a second location 186 different from the first location 184. In another example, the vacuum pump 160 and the second vacuum pump 114 can exhaust to a T-junction and exhaust from both the vacuum pump 160 and the second vacuum pump 114 can flow from the T-junction to a single point in the rough line 176.

[0027]

[0029] In some embodiments, the process kit components include a quartz ring 130 disposed around the pedestal 150, for example, around the dielectric plate 152 and the edge ring 185. The quartz ring 130 can promote process uniformity of the substrate 122. In some embodiments, the quartz ring 130 includes a notched upper inner edge configured to support the outer edge of the edge ring 185. In some embodiments, a lower edge ring 134 is disposed around the pedestal 150. In some embodiments, the lower edge ring 134 is disposed between the pedestal 150 and the liner 104. In some embodiments, the lower edge ring 134 is disposed below the quartz ring 130. In some embodiments, the lower edge ring 134 is made of quartz. In some embodiments, a second edge ring 218 can be disposed on the quartz ring 130 and surround the pedestal 150. The second edge ring 218 can be made of a similar material as the edge ring 185.

[0028]

[0030] In some embodiments, a third gap (e.g., third gap 224 in FIG. 2 ) is disposed between the lower edge ring 134 and the pedestal 150. The third gap 224 allows for thermal expansion of one or more components of the pedestal 150. In some embodiments, the vacuum pump 160 is fluidly coupled to the third gap 224 for evacuating the third gap 224. In some embodiments, the third gap 224 is fluidly coupled to the vacuum pump 160 via a channel 178 that extends from one or more of the plurality of first gaps 174 to the third gap 224. In some embodiments, the channel 178 is disposed in the insulator plate 126. In some embodiments, the channel 178 extends radially outward from the first gap 174 to the third gap 224. Pumping down the third gap 224 advantageously reduces or prevents glow-up and ignition in the third gap 224. By pumping down the third gap 224, the third gap 224 can be widened, advantageously reducing RF coupling between the pedestal 150 and components disposed around the pedestal 150, such as the lower ring 134. In some embodiments, the lower edge ring 134 can include a channel (not shown) extending from the third gap 224 to a fourth gap (e.g., the fourth gap 304 shown in FIG. 3) between the liner 104 and the lower edge ring 134 such that the vacuum pump 160 can pump down the fourth gap. Thus, in some embodiments, a single pump (e.g., the vacuum pump 160) can pump down various gaps or cavities disposed in the substrate support 124. In other embodiments, multiple vacuum pumps can be used to pump down various gaps or cavities disposed in the substrate support 124.

[0029]

[0031] In some embodiments, the pedestal 150 includes a gas distribution channel 138 that extends from a lower surface of the pedestal 150 (e.g., a bottom surface of the insulator plate 126) to various openings in an upper surface of the pedestal 150. The gas distribution channel 138 is configured to supply a backside gas, such as nitrogen (N) or helium (He), to the upper surface of the pedestal 150, which acts as a heat transfer medium. The gas distribution channel 138 is in fluid communication with a backside gas supply 141 via a gas conduit 142 to control the temperature and / or temperature profile of the pedestal 150 during use. In some embodiments, the gas distribution channel 138 is configured to provide a gas pressure for heat transfer and temperature control of the edge ring 185, independent of the temperature of the dielectric plate 152. The backside gas entering the plurality of first gaps 174 is pumped away by a vacuum pump 160.

[0030]

[0032] The processing region 119 is also coupled and in fluid communication with a process gas supply 118 that can supply one or more process gases to the chamber 100 for processing a substrate disposed therein. In some embodiments, the process gas supply 118 can supply one or more process gases to the processing region 119 through a showerhead (not shown) for more uniform gas distribution.

[0031]

[0033] The chamber 100 includes a slit valve 144 to facilitate transfer of the substrate 122 in and out of the interior region 121. In some embodiments, a transfer robot (not shown) is configured to transfer the substrate 122. The transfer robot may also be advantageously configured to transfer the edge ring 185 in and out of the interior region 121 for replacement. The slit valve 144 may be coupled to the lid 101 or the chamber body 106.

[0032]

[0034] In the process, for example, a plasma 192 may be generated in the processing region 119 to perform one or more processes. The plasma 192 may be generated by coupling power from a plasma power source (e.g., RF plasma power source 170) to a process gas via one or more electrodes near or within the processing region 119 to ignite the process gas and generate the plasma 192. A bias power source (e.g., bias power source 117) may provide bias power to the pedestal 150 to attract ions from the plasma 192 toward the substrate 122. The bias power source 117 may provide bias power to the edge ring 185 and the dielectric plate 152. For example, the bias power source 117 may include a single power source shared by both the edge ring 185 and the dielectric plate 152.

[0033]

[0035] 2 is a schematic cross-sectional side view of a substrate support according to at least some embodiments of the present disclosure. In some embodiments, a plurality of process kit lift pins 230 extend through the substrate support 124 and are configured to selectively raise or lower a process kit component, such as the edge ring 185. The plurality of process kit lift pins 230 are coupled to a process kit lift assembly 204 to raise or lower the process kit component. In some embodiments, the plurality of process kit lift pins 230 includes three lift pins symmetrically arranged around the substrate support 124. The substrate lift assembly 128 includes a plurality of first actuators 208. The process kit lift assembly 204 includes a plurality of second actuators 222.

[0034]

[0036] The plurality of process kit lift pins 230 are generally disposed radially outward of the plurality of substrate lift pins 168. The plurality of second gaps 232 are disposed between the plurality of process kit lift pins 230 and respective ones of the plurality of process kit lift pin openings 234. In some embodiments, the vacuum pump 160 is coupled to each of the plurality of second gaps 232 and configured to pump down the plurality of second gaps 232 to a pressure of about 10 mTorr or less. In some embodiments, the plurality of substrate lift pins 168 and the plurality of process kit lift pins 230 are aligned along a common radius of the pedestal 150. In some embodiments, the channel 178 extends from one or more of the plurality of second gaps 232 to the third gap 224. In some embodiments, the third gap 224 is sealed from the processing region 119. For example, in some embodiments, a first O-ring 242 and a second O-ring 246 are disposed between the lower edge ring 134 and the pedestal 150 with the third gap 224 disposed therebetween.

[0035]

[0037] In some embodiments, the vacuum pump 160 is disposed in the lower region 180. In some embodiments, the vacuum pump 160 is coupled to the base plate 102. In some embodiments, the vacuum pump 160 is disposed between one of the substrate lift assemblies 128 and one of the process kit lift assemblies 204. In some embodiments, the vacuum line 166 includes one or more joints 280 of the substrate support 124 that divide the vacuum line 166 into a first vacuum line 282 that extends to one of the plurality of first gaps 174 and a second vacuum line 284 that extends to one of the plurality of second gaps 232. In some embodiments, the one or more joints 280 are formed in the base plate 102. In some embodiments, the vacuum line 166 extends to a sidewall of the plurality of substrate lift pin openings 171. In some embodiments, the vacuum line 166 extends to a sidewall of the plurality of process kit lift pin openings 234.

[0036]

[0038] The edge ring 185 may advantageously extend the process environment beyond the diameter of the substrate 122. However, the plasma 192 may penetrate into any gap between the edge ring 185 and the substrate 122, causing degradation of the dielectric plate 152. In some embodiments, the insert ring 216 is disposed in an annular groove in the top surface of the dielectric plate 152 to protect the dielectric plate 152 from degradation. In some embodiments, the insert ring 216 is separate from the edge ring 185. In some embodiments, the insert ring 216 is integrally formed with the edge ring 185. In some embodiments, the edge ring 185 and the insert ring 216 may be made of silicon (Si), silicon nitride (SiN), silicon carbide (SiC), silicon oxide (SiO2), or quartz. In some embodiments, the edge ring 185 is made of a different material than the insert ring 216.

[0037]

[0039] In some embodiments, at least some of the various conduits disposed in the substrate support 124 may be disposed in the equipment cable 250. For example, the chucking electrode lines 143 may extend through the equipment cable 250. In some embodiments, the equipment cable 250 extends through the lower region 180 to the substrate support 124. In some embodiments, the pedestal 150 includes an RF plate 206 disposed between the cooling plate 120 and the insulator plate 126. In some embodiments, the RF plate 206 is made of a metallic material, such as aluminum. The RF plate 206 is generally coupled to the bias power supply 117 to provide RF bias power to the pedestal 150. In some embodiments, the substrate support 124 includes a temperature probe 220 configured to measure a temperature of the dielectric plate 152.

[0038]

[0040] 3 is a cross-sectional side view of a portion of the substrate support 124 according to at least some embodiments of the present disclosure. In some embodiments, an insulator sleeve 308 is disposed in each of the plurality of substrate lift pin openings 171 and surrounds each of the plurality of substrate lift pins 168. A plurality of first gaps 174 extend between each of the insulator sleeves 308 and a respective one of the plurality of substrate lift pins 168. In some embodiments, the insulator sleeve 308 is made of a polymeric material and is configured to reduce or prevent arcing, glow discharge, or lighting in the plurality of first gaps 174. In some embodiments, the insulator sleeve 308 is disposed in each of the plurality of process kit lift pin openings 234 and surrounds each of the plurality of process kit lift pins 230 with a plurality of second gaps 232 extending therebetween. In some embodiments, a third O-ring 310 is disposed around each of the plurality of process kit lift pins 230 to provide a seal at the interface between the RF plate 206 and the insulator plate 126. In some embodiments, a fourth O-ring 316 is disposed around each of the plurality of substrate lift pins 168 to provide a seal at the interface between the RF plate 206 and the insulator plate 126 .

[0039]

[0041] In use, when the substrate 122 is placed on or electrostatically chucked to the dielectric plate 152, the substrate 122 provides a first seal separating the processing region 119 from the plurality of first gaps 174 and the plurality of second gaps 232. In some embodiments, the plurality of substrate lift pins 168 and the plurality of process kit lift pins 230 have outwardly tapered upper portions 312 to provide a second seal with the pedestal 150 when in the lowered position, further reducing unintentional ingress of process chemistry and / or substrate heat transfer or cooling gases into the gaps of the substrate support 124.

[0040]

[0042] While the forgoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. 1. A substrate support for use in a substrate processing chamber, comprising: a pedestal having a first surface configured to support a substrate and a second surface opposite the first surface; a plurality of substrate lift pins extending through the pedestal, a plurality of first gaps being disposed between the plurality of substrate lift pins and respective ones of a plurality of substrate lift pin openings of the pedestal; a vacuum line extending from the plurality of substrate lift pin openings and configured to pump down the plurality of substrate lift pin openings; A substrate support comprising:

2. 10. The substrate support of claim 1, wherein the pedestal includes a dielectric plate having an electrode embedded therein and a cooling plate coupled to the dielectric plate, the cooling plate including cooling channels configured to circulate a coolant.

3. 2. The substrate support of claim 1, further comprising a plurality of process kit lift pins extending through the pedestal and disposed radially outward of the plurality of substrate lift pins, a plurality of second gaps being disposed between the plurality of process kit lift pins and respective ones of a plurality of process kit lift pin openings, and the vacuum line configured to pump down the plurality of second gaps.

4. 4. The substrate support of claim 3, wherein the vacuum line includes a junction disposed in the substrate support and dividing the vacuum line into a first exhaust line extending into one of the plurality of first gaps and a second exhaust line extending into one of the plurality of second gaps.

5. a lower edge ring disposed around the pedestal and defining a third gap between the lower edge ring and the pedestal; a channel extending from at least one of the plurality of first gaps to the third gap such that the vacuum line is configured to pump down the plurality of first gaps and the third gap; The substrate support of claim 1 further comprising:

6. The substrate support of claim 5 , wherein the pedestal includes an insulator plate coupled to a cooling plate, the channel being disposed in the insulator plate.

7. The substrate support of claim 1 , further comprising a vacuum pump coupled to the vacuum line for pumping down the plurality of substrate lift pin openings.

8. 7. The substrate support of claim 1, wherein the plurality of substrate lift pins have an outwardly tapered upper portion to provide a seal with the pedestal when the plurality of substrate lift pins are in a lowered position.

9. The substrate support of claim 1 , wherein the vacuum lines extend to sidewalls of the plurality of substrate lift pin openings.

10. 1. A process chamber for processing a substrate, comprising: a chamber body defining a processing region therein; A substrate support according to claim 1 , the substrate support being disposed in the chamber body and having an upper surface exposed to the processing region; a vacuum pump coupled to each of the plurality of first gaps via a vacuum line extending to the plurality of substrate lift pin openings; A process chamber comprising:

11. 11. The process chamber of claim 10, further comprising a second vacuum pump fluidly coupled to the processing region and configured to pump down the processing region.

12. 12. The process chamber of claim 11, wherein the chamber body defines a second region disposed below the substrate support and fluidly coupled to the processing region, the second region being upstream from the second vacuum pump.

13. The process chamber of claim 12 , wherein the vacuum pump exhausts to the second region.

14. 12. The process chamber of claim 11, further comprising a rough line, the vacuum pump pumping into the rough line at a first location and the second vacuum pump pumping into the rough line at a second location different from the first location.

15. 1. A process chamber for processing a substrate, comprising: a chamber body defining a processing region therein; A substrate support according to claim 1 , the substrate support being disposed in the chamber body and having an upper surface exposed to the processing region; a first vacuum pump coupled to each of the plurality of first gaps and configured to pump down the plurality of first gaps to a first pressure; a second vacuum pump coupled to the chamber body and configured to pump down the processing volume to a process pressure; A process chamber comprising:

16. 16. The process chamber of claim 15, wherein the first vacuum pump exhausts to a second region upstream of the second vacuum pump or to a rough line that is separate from the second vacuum pump.

17. 16. The process chamber of claim 15, further comprising: a plurality of process kit lift pins extending through the pedestal and disposed radially outward of the plurality of substrate lift pins, a plurality of second gaps disposed between the plurality of process kit lift pins and respective ones of the plurality of process kit lift pin openings, and the first vacuum pump coupled to each of the plurality of second gaps and configured to pump down the plurality of second gaps.

18. 16. The process chamber of claim 15, wherein the pedestal comprises a dielectric plate having an electrode embedded therein and a cooling plate coupled to the dielectric plate, and further comprises a lower edge ring disposed around the dielectric plate, a third gap is disposed between the lower edge ring and the dielectric plate, and the first vacuum pump is fluidly coupled to the third gap via a channel.

19. a first O-ring and a second O-ring disposed between the lower edge ring and the pedestal, the third gap being disposed between the first O-ring and the second O-ring; The process chamber of claim 18 further comprising:

20. 16. The process chamber of claim 15, wherein the chamber body defines a lower region disposed below the substrate support, and the first vacuum pump is disposed in the lower region.

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