Patent Publication Number: US-2022223387-A1

Title: High power electrostatic chuck with features preventing he hole light-up/arcing

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority of U.S. application Ser. No. 62/754,308, filed Nov. 1, 2018, which is incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     The disclosure relates to an apparatus for processing substrates. More specifically the disclosure relates to an apparatus for plasma processing substrates. 
     In various plasma processing chambers, helium (He) is flowed to a backside of a substrate on an electrostatic chuck (ESC) in order to provide temperature control. Radio frequency (RF) power used for forming a plasma may cause a secondary plasma light-up in the ESC cavities due to high voltage associated with plasma formation. The light-up would promote arcing between any two surfaces with a high electric potential difference between them. Such arcing will cause damage to the ESC. 
     SUMMARY 
     To achieve the foregoing and in accordance with the purpose of the present disclosure, a spark suppression apparatus for a helium line in an electrostatic chuck in a plasma processing chamber is provided. The spark suppression apparatus comprises a dielectric multilumen plug in the helium line, wherein the dielectric multilumen plug has a plurality of lumens, wherein the plurality of lumens are numbered between 30 to 100,000 lumens and have a width of between 1 micron and 200 microns. 
     These and other features of the present disclosure will be described in more detail below in the detailed description and in conjunction with the following figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
         FIG. 1  is a schematic cross-sectional view of a spark suppression apparatus in part of an electrostatic chuck (ESC) that may be used in an embodiment. 
         FIG. 2  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 3  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 4  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 5  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 6  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 7  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 8  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 9  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC that may be used in another embodiment. 
         FIG. 10  is a schematic view of a processing chamber that may be used in an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The present disclosure will now be described in detail with reference to a few embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art, that the present disclosure may be practiced without some or all of these specific details. In other instances, well-known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present disclosure. 
     New semiconductor manufacturing processes require very high RF power plasmas. Increasing RF power causes an increase in RF currents and total voltages applied to the Electrostatic Chuck (ESC—wafer susceptor). At the same time, new plasma etch processes require significantly lower RF frequencies (e.g. 2 MHz, 400 kHz, or lower) than previously required. Low RF frequencies cause an additional increase in RF voltage applied across ESC ceramic. High voltage applied across ceramic may cause electrical discharge (arcing) between a wafer and a baseplate or ignition (light-up) of heat transfer gas (e.g. He) in the gas supplying holes. Arcing of the ESC usually causes catastrophic destruction of the part accompanied by wafer destruction, possible damage to other chamber components, and manufacturing process interruption. In the case of the heat transfer gas light-up, ESC destruction could be either catastrophic or could slowly develop affecting multiple wafers with semiconductor device damage, being detected only at much later steps of the manufacturing process. In both cases, ESC failure causes significant loss in wafer production and manufacturer&#39;s revenue. 
     For low-voltage applications, it is common to use straight holes in a ceramic plate with ceramic sleeves in baseplates opposing holes in the ceramic plate and preventing direct line of sight. For mid-low voltage applications, ceramic sleeves in baseplates are replaced with porous plugs providing a higher withstand voltage than ceramic sleeves. For mid-voltage applications, porous plugs are inserted in the ceramic plate, in addition to the sleeves in the baseplate. Further breakdown voltage improvement requires new solutions. 
     An embodiment provides a solution for ESC arcing and He light-up problems by introducing plugs (made of ceramic material, e.g., alumina A 1   2   0   3  or aluminum nitride A 1 N), with small (diameter  0 . 1 - 100  micrometers) openings into He holes. The plugs compartmentalize the He hole volume into smaller micro-volumes that limit light-up probability by reducing the number of charged particles&#39; collisions and prevent line of sight between a wafer and metal parts of the chuck below the top ceramic plate while ensuring needed He flow through the holes for the wafer backside cooling. 
     To facilitate understanding,  FIG. 1  is a schematic cross-sectional view of a spark suppression apparatus in part of an electrostatic chuck (ESC)  100  that may be used in an embodiment. In this embodiment, the ESC  100  comprises a base plate  104  bonded to a ceramic plate  108  by a bond layer  112 . In this embodiment, the base plate  104  is a conductive metal base plate  104 , e.g. aluminum. The base plate  104  has a He supply line hole  116 . At an output end of the He supply line hole  116  is a porous plug  120 . The He supply line hole  116  is on a first side of the porous plug  120 . In this embodiment, the porous plug  120  is a porous dielectric plug of ceramic alumina or aluminum nitride with a porosity of 30-50%. In this embodiment, the porous plug  120  has a diameter of 3 to 10 mm that is more than 3 times the characteristic dimension (diameter or width) of the supply line hole  116 . In this example, the porous plug  120  extends to the top surface of the base plate  104 . The porous plug  120  may have various shapes: e.g., straight as shown in  FIG. 1  or with a T-shaped outer envelope as shown in  FIG. 6 ,  FIG. 7 ,  FIG. 8 , or  FIG. 9 . 
     On a second side of the porous plug  120  opposite from the first side of the porous plug is a first plenum  124 . The porous plug  120  is on a first side of the first plenum  124 . The first plenum  124  is formed in the bond layer  112 . On a second side of the first plenum  124 , opposite from the first side, is a dielectric multilumen plug  128 , made of alumina or aluminum nitride with a plurality of small through holes, and the ceramic plate  108 . In this embodiment, the dielectric multilumen plug  128  is bonded to the ceramic plate  108 . In this example, the dielectric multilumen plug  128  is a dielectric plug that has 50 to 100,000 lumens, where each lumen has a diameter of between 1 micron and 200 microns. The lumens extend from a first side of the dielectric multilumen plug  128 , adjacent to the first plenum  124  to a second side of the dielectric multilumen plug  128  opposite from the first side. The ceramic plate  108  has a thickness between 0.5 mm and 3 mm. The dielectric multilumen plug  128  has a height of between 0.1 mm and 2.5 mm. In this embodiment, the lumens are straight round tubes forming a honeycomb cross-section. Since the lumens are straight and extend across the height of the dielectric multilumen plug  128 , the lumens have a length of between 0.1 mm and 2.5 mm. In this embodiment, the dielectric multilumen plug  128  has a diameter of 3 to 5 mm. In this embodiment, the dielectric multilumen plug  128  is made of alumina. 
     A second plenum  132  is on the second side of the dielectric multilumen plug  128 . At least one He hole  136  extends from the second plenum  132  to a surface of the ceramic plate  108 . In this example, the at least one He hole  136  has a diameter of between 0.02 to 0.3 mm. In this embodiment, other parts of the ESC  100  has other He supply line holes  116 , porous plugs  120 , first plenums  124 , dielectric multilumen plugs  128 , second plenums  132 , and He holes  136 . At the top surface of the ceramic plate  108 , the at least one He hole  136  is shown as being wider, since the wider part may be part of a groove or channel connected between a plurality of He holes  136  at the top surface of the ceramic plate  108 . The He supply line hole  116  and the at least one He hole  136  form a helium line, wherein the He supply line hole  116  is a first portion of the He line and the at least one He hole  136  is a second portion of the He line. The second plenum has a width  148 . The first plenum  124  has a width. The width of the first plenum  124  is about the same as the diameter of the porous portion of the porous plug  120  and the width  148  of the second plenum  132  is about 80% of the dielectric multilumen plug  128  diameter and at least two times the width of the He supply line hole  116 . 
     This embodiment has been found to reduce arcing. As a result, damage to the wafers has been reduced. In addition, the utilization time/coefficient has been improved. Without being bound by theory, it is believed that providing a large number of thin lumens significantly reduces arcing and allows sufficient He flow. In addition, the porous plug  120  increases the path length that electricity must travel in order to reach a conductive material. This further reduces arcing. 
       FIG. 2  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  200  that may be used in another embodiment. In this embodiment, the ESC  200  comprises a base plate  204  bonded to a ceramic plate  208  by a bond layer  212 . In this embodiment, the base plate  204  is a conductive metal base plate  204 , e.g. aluminum. The base plate  204  has a He supply line hole  216 . At an output end of the He supply line hole  216  is a porous plug  220 . The He supply line hole  216  is on a first side of the porous plug  220 . In this embodiment, the porous plug  220  is ceramic alumina or aluminum nitride with a porosity of 30-50%. In this embodiment, the porous plug  220  has a diameter that is  3  to 10  mm In this example, the porous plug  220  extends to a top surface of the base plate  204 . 
     On a second side of the porous plug  220  opposite from the first side of the porous plug  220  is a first plenum  224 . The porous plug  220  is on a first side of the first plenum  224 . The first plenum  224  is formed in the bond layer  212 . On a second side of the first plenum  224 , opposite from the first side, is a dielectric multilumen plug  228 , made of alumina or aluminum nitride with a plurality of small through holes, and the ceramic plate  208 . In this embodiment, the dielectric multilumen plug  228  has a solid core  230  at the center. The dielectric multilumen plug  228  is bonded to the ceramic plate  208 . In this example, the dielectric multilumen plug  228  has 30 to 100,000 lumens, where each lumen has a diameter of between 1 micron and 200 microns. The lumens extend from a first side of the dielectric multilumen plug  228 , adjacent to the first plenum  224  to a second side of the dielectric multilumen plug  228  opposite from the first side. 
     A second plenum  232  is on the second side of the dielectric multilumen plug  228 . At least one He hole  236  extends from the second plenum  232  to a surface of the ceramic plate  208 . In this example, the at least one He hole  236  has a diameter of between 0.05 to 0.3 mm. In this embodiment, the solid core  230  has a diameter greater than the diameter of the at least one He hole  236 , such as a cluster of He holes (1-6 holes per location). The solid core  230  has a width and is positioned so as to prevent a line of sight path from the He supply line hole  216  to the at least one He hole  236  through the lumens of the dielectric multilumen plug  228 . In this embodiment, further reducing the line of sight of the He flow further reduces arcing. The He supply line hole  216  and the at least one He hole  236  form a helium line, wherein the He supply line hole  216  is a first portion of the He line and the at least one He hole  236  is a second portion of the He line. 
       FIG. 3  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  300  that may be used in another embodiment. In this embodiment, the ESC  300  comprises a base plate  304  bonded to a ceramic plate  308  by a bond layer  312 . In this embodiment, the base plate  304  is a conductive metal base plate  304 , e.g. aluminum. The base plate  304  has a He supply line hole  316 . At an output end of the He supply line hole  316  is a first plenum  318 . The He supply line hole  316  is on a first side of the first plenum  318 . On a second side of the first plenum  318  is a first side of a first dielectric multilumen plug  320  made of alumina or aluminum nitride with a plurality of small through holes. In this embodiment, the first dielectric multilumen plug  320  has a solid core  322  at the center. The first dielectric multilumen plug  320  is bonded to the base plate  304 . In this example, the first dielectric multilumen plug  320  has 30 to 100,000 lumens, where each lumen has a diameter of between 1 micron and 200 microns. The lumens extend from a first side of the first dielectric multilumen plug  320 , adjacent to the first plenum  318  to a second side of the first dielectric multilumen plug  320  opposite from the first side. In this example, the first dielectric multilumen plug  320  extends to a top surface of the base plate  304 . 
     On a second side of the first dielectric multilumen plug  320  opposite from the first side of the first dielectric multilumen plug  320  is a second plenum  324 . The first dielectric multilumen plug  320  is on a first side of the second plenum  324 . The second plenum  324  is formed in the bond layer  312 . On a second side of the second plenum  324 , opposite from the first side, is a second dielectric multilumen plug  328 , made of alumina or aluminum nitride with a plurality of small through holes, and the ceramic plate  308 . In this embodiment, the second dielectric multilumen plug  328  has a solid core  330  at the center. The second dielectric multilumen plug  328  is bonded to the ceramic plate  308 . In this example, the second dielectric multilumen plug  328  has 30 to 100,000 lumens, where each lumen has a diameter of between 1 micron and 200 microns. The lumens extend from a first side of the second dielectric multilumen plug  328 , adjacent to the second plenum  324  to a second side of the second dielectric multilumen plug  328  opposite from the first side. 
     A third plenum  332  is on the second side of the second dielectric multilumen plug  328 . At least one He hole  336  extends from the third plenum  332  to a surface of the ceramic plate  308 . In this example, the at least one He hole  336  has a diameter of between 0.05 to 0.3 mm. The solid core  330  of the second dielectric multilumen plug  328  has a diameter greater than the diameter of the at least one He hole  336 . The solid core  322  of the first dielectric multilumen plug  320  has a diameter that is greater than the diameter of the solid core  330  of the second dielectric multilumen plug  328  and greater than the diameter of the He supply line hole  316 . The solid core  322  of the first dielectric multilumen plug  320  and the solid core  330  of the second dielectric multilumen plug  328  each have a width and are positioned so as to prevent a line of sight path from the He supply line hole  316  to the at least one He hole  336  through the lumens of the first dielectric multilumen plug  320  and the second dielectric multilumen plug  328 . The lumens allow for an increased He flow. The He supply line hole  316  and the at least one He hole  336  form a helium line, wherein the He supply line hole  316  is a first portion of the He line and the at least one He hole  336  is a second portion of the He line. 
     In other embodiments, the solid core  322  of the first dielectric multilumen plug  320  and/or the solid core  330  of the second dielectric multilumen plug  328  may be replaced by multiple lumens. Four combinations may be provided. The widths of the solid cores may also vary to add additional embodiments. 
       FIG. 4  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  400  that may be used in another embodiment. In this embodiment, the ESC  400  comprises a base plate  404  bonded to a ceramic plate  408  by a bond layer  412 . In this embodiment, the base plate  404  is a conductive metal base plate  404 . The base plate  404  has a He supply line hole  416 . At an output end of the He supply line hole  416  is a first plenum  418 . The He supply line hole  416  is on a first side of the first plenum  418 . On a second side of the first plenum  418  is a first side of a dielectric multilumen plug  420 . In this embodiment, the dielectric multilumen plug  420  has a solid core  422  at the center. The dielectric multilumen plug  420  is bonded to the base plate  404 . In this example, the dielectric multilumen plug  420  has 30 to 100,000 lumens, where each lumen has a width of between 1 micron and 200 microns. The lumens extend from a first side of the dielectric multilumen plug  420 , adjacent to the first plenum  418  to a second side of the dielectric multilumen plug  420  opposite from the first side. In this example, the dielectric multilumen plug  420  extends to a surface of the base plate  404 . 
     On a second side of the dielectric multilumen plug  420  opposite from the first side of the dielectric multilumen plug  420  is a second plenum  424  located in the bond layer  412 . The dielectric multilumen plug  420  is on a first side of the second plenum  424 . 
     On a second side of the second plenum  424 , opposite from the first side, is at least one He hole  436  that extends from the second plenum  424  to a surface of the ceramic plate  408 . In this example, the at least one He hole  436  has a diameter of between  0 . 03  to  0 . 3  mm The solid core  422  of the dielectric multilumen plug  420  has a width and is positioned so as to prevent a line of sight path from the He supply line hole  416  to the at least one He hole  436 , such as a cluster of smaller He holes, through the lumens of the dielectric multilumen plug  420 . 
     This embodiment uses only a single plug. By bonding the dielectric multilumen plug  420  in the base plate  404 , the dielectric multilumen plug  420  may be larger, allowing for a single plug. In this embodiment, the ceramic plate  408  has a thickness between 0.5 mm and 1.5 mm. The dielectric multilumen plug  420  has a thickness that is much greater than 1 mm. For example, the dielectric multilumen plug  420  has a thickness or height  421  of between 2 mm to 10 mm. In this example, the solid core  422  has a diameter of 1 to 2 mm. The He supply line hole  416  and the at least one He hole  436  form a helium line, wherein the He supply line hole  416  is a first portion of the He line and the at least one He hole  436  is a second portion of the He line. 
       FIG. 5  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  500  that may be used in another embodiment. In this embodiment, the ESC  500  comprises a base plate  504  bonded to a ceramic plate  508  by a bond layer  512 . In this embodiment, the base plate  504  is a conductive metal base plate  504 , e.g. aluminum. The base plate  504  has a He supply line hole  516 . At an output end of the He supply line hole  516  is a first plenum  518 . The He supply line hole  516  is on a first side of the first plenum  518 . On a second side of the first plenum  518  is a first side of a first dielectric multilumen plug  520 . In this embodiment, the first dielectric multilumen plug  520  has a solid core  522  at the center. The first dielectric multilumen plug  520  is bonded to the base plate  504 . In this example, the first dielectric multilumen plug  520  has 30 to 100,000 lumens, where each lumen has a diameter of between 1 micron and 200 microns. The lumens extend from a first side of the first dielectric multilumen plug  520 , adjacent to the first plenum  518  to a second side of the first dielectric multilumen plug  520  opposite from the first side. In this example, the first dielectric multilumen plug  520  extends to a surface of the base plate  504 . 
     On a second side of the first dielectric multilumen plug  520 , opposite from the first side of the first dielectric multilumen plug  520 , is a second plenum  524 . The first dielectric multilumen plug  520  is on a first side of the second plenum  524 . The second plenum  524  is formed in the bond layer  512 . On a second side of the second plenum  524 , opposite from the first side, is a second dielectric multilumen plug  528 , made of alumina or aluminum nitride with a plurality of small through holes, and the ceramic plate  508 . In this embodiment, the second dielectric multilumen plug  528  has a solid core  530  at the center. The second dielectric multilumen plug  528  is bonded to the ceramic plate  508 . In this example, the second dielectric multilumen plug  528  has 30 to 100,000 lumens, where each lumen has a diameter of between 1 micron and 200 microns. The lumens extend from a first side of the second dielectric multilumen plug  528 , adjacent to the second plenum  524  to a second side of the second dielectric multilumen plug  528  opposite from the first side. In this embodiment, the second dielectric multilumen plug  528  extends into the second plenum  524 . The first side of the second dielectric multilumen plug  528  extends past the surface of the ceramic plate  508  into the layer or region defined by the bond layer  512 . In this embodiment, the second dielectric multilumen plug  528  extends into the second plenum  524  to form an overhang of about 50 to 80% of the gap distance, in this specific case: between 0.01 mm to 0.25 mm. In this example, the gap distance is the thickness of the bond layer  512 . 
     A third plenum  532  is on the second side of the second dielectric multilumen plug  528 . At least one He hole  536  extends from the third plenum  532  to a surface of the ceramic plate  508 . In this example, the at least one He hole  536  has a diameter of between 0.2 to 0.3 mm. The solid core  522  of the first dielectric multilumen plug  520  and the solid core  530  of the second dielectric multilumen plug  528  each have a width and are positioned so as to prevent a line of sight path from the supply line hole  516  to the at least one He hole  536  through the lumens of the first dielectric multilumen plug  520  and the second dielectric multilumen plug  528 . The lumens allow for an increased He flow. By extending the second dielectric multilumen plug  528  into the second plenum  524  the height of the second plenum  524  is reduced and arcing is further reduced. 
       FIG. 6  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  600  that may be used in another embodiment. In this embodiment, the ESC  600  comprises a base plate  604  bonded to a ceramic plate  608  by a bond layer  612 . In this embodiment, the base plate  604  is a conductive metal base plate  604 , e.g. aluminum. The base plate  604  has a He supply line hole  616 . At an output end of the He supply line hole  616  is a cavity  618 . In this embodiment, the cavity  618  is T-shaped. Partially filling the T-shaped cavity  618  is a dielectric multilumen plug  620 . In this embodiment, the dielectric multilumen plug  620  has a central bore  622  with a diameter of 2 to 10 mm extending partially through the center of the dielectric multilumen plug  620 . A plurality of He passage holes  623  extends from the central bore  622  to a first plenum  624  within the dielectric multilumen plug  620 . In this embodiment, the first plenum  624  has a diameter of between 1 mm to 10 mm and a height of 0.01 to 0.5 mm. In this embodiment, there are between 1 to 300 He passage holes  623  with diameters from 30 microns to 1 mm. A plurality of lumens  628  extend from the first plenum  624  to a second plenum  632  adjacent to a surface of the dielectric multilumen plug  620 . In this example, the dielectric multilumen plug  620  has 30 to 500 lumens  628 , where each lumen  628  has a diameter of between 30 micron and 150 microns. The plurality of lumens  628  may be placed to form concentric circles. On a second side of the second plenum  632 , opposite from the first side, is at least one He hole  636  that extends from the second plenum  632  to a surface of the ceramic plate  608 . In this example, the at least one He hole  636  has a diameter of between 0.2 to 0.3 mm. The He supply line hole  616  and the at least one He hole  636  form a helium line, wherein the He supply line hole  616  is a first portion of the He line and the at least one He hole  636  is a second portion of the He line. 
     The He passage holes  623  and plurality of lumens  628  are located in a way that there is no direct line of sight from the top of the dielectric multilumen plug  620  to its bottom. E.g., if arranged in circles, diameters of circles by the He passage holes  623  are significantly different from diameters of the circles formed by the plurality of lumens  628 . In this embodiment, a multilumen core  640  is attached by bonding or ceramic lamination or any other process, to an outer plug  644  to form the dielectric multilumen plug  620 . The plurality of lumens  628  is formed to pass through the multilumen core  640 , as shown. The bottom of the multilumen core  640  is spaced apart from a top of a central cavity in the outer plug  644  to provide a space forming the first plenum  624 . Such a configuration allows for the dielectric multilumen plug  620  to be more easily formed. The dielectric multilumen plug  620  is T-shaped. In this embodiment, the top of the T-shaped dielectric multilumen plug  620  is bonded to the top of the T-shaped cavity  618  of the base plate  604 . A gap  652  is between the bottom of the T-shaped dielectric multilumen plug  620  and the T-shaped cavity  618 . In this embodiment, the gap is between 0.1 mm and 1 mm 
     Electric charges may travel along the surface of T-shaped dielectric multilumen plug  620  and reach the conductive base plate  604 . The gap  652  creates a longer surface length from the at least one He hole  636  through the second plenum  632 , the plurality of lumens  628 , the first plenum  624 , the plurality of He passage holes  623 , the central bore  622 , and the outer surface of the bottom of the outer plug  644  to the base plate  604 . The increase in the surface length reduces arcing. Since top of the T-shaped dielectric multilumen plug  620  is bonded to the top of the T-shaped cavity  618  of the base plate  604  with a gas-tight seal, the gap  652  is gas-tight, so that He passing from the He supply line hole  616  flows through the central bore  622 , the plurality of He passage holes  623 , the first plenum  624 , the lumens  628 , the second plenum  632  to the He holes  636 . This embodiment has been found to prevent arcing at over 50 kW. 
       FIG. 7  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  700  that may be used in another embodiment. In this embodiment, the ESC  700  comprises a base plate  704  bonded to a ceramic plate  708  by a bond layer  712 . In this embodiment, the base plate  704  is a conductive metal base plate  704 . The base plate  704  has a He supply line hole  716 . At an output end of the He supply line hole  716  is a cavity  718 . In this embodiment, the cavity  718  is T-shaped. Partially filling the cavity  718  is a dielectric multilumen plug  720 . In this embodiment, the dielectric multilumen plug  720  has a central core  740  with a center bore  722  with a diameter of 2 to 10 mm extending partially through the center of the dielectric multilumen plug  720  to a first plenum  724  within the dielectric multilumen plug  720 . A plurality of lumens  728  extends from the first plenum  724  to a second plenum  732  adjacent to a surface of the dielectric multilumen plug  720 . In this example, the dielectric multilumen plug  720  has 30 to 500 lumens  728 , where each lumen  728  has a diameter of between 1 micron and 150 microns. The plurality of lumens  728  may be placed to form concentric circles. All lumens  728  must be located away from the center bore  722  to avoid a direct line of sight from the top of the dielectric multilumen plug  720  to its bottom. On a second side of the second plenum  732 , opposite from the first side, is at least one He hole  736  that extends from the second plenum  732  to a surface of the ceramic plate  708 . In this example, the at least one He hole  736  has a diameter of between 0.02 to 0.3 mm. The He supply line hole  716  and the at least one He hole  736  form a helium line, wherein the He supply line hole  716  is a first portion of the He line and the at least one He hole  736  is a second portion of the He line. 
     The plurality of lumens  728  is located in a way that there is no direct line of sight from the top of the dielectric multilumen plug  720  to the bottom of the dielectric multilumen plug  720 . In this embodiment, a central core  740  is bonded in an outer plug  744  to form the dielectric multilumen plug  720 . The lumens  728  are formed to pass through the outer plug  744 , as shown. A top surface of the central core  740  is spaced apart from a surface of a central cavity in the outer plug  744  to provide a space forming the first plenum  724 . Such a configuration allows for the dielectric multilumen plug  720  to be more easily formed. The dielectric multilumen plug  720  is 
     T-shaped. In this embodiment, the top of the T-shaped dielectric multilumen plug  720  is bonded to the top of the T-shaped cavity  718  of the base plate  704 . A gap is between the bottom of the T-shaped dielectric multilumen plug  720  and the T-shaped cavity  718  to reduce arcing, as explained in the previous embodiment. In this embodiment, the gap is between 0.1 mm and 1 mm. 
       FIG. 8  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  800  that may be used in another embodiment. In this embodiment, the ESC  800  comprises a base plate  804  bonded to a ceramic plate  808  by a bond layer  812 . In this embodiment, the base plate  804  is a conductive metal base plate  804 . The base plate  804  has a He supply line hole  816 . At an output end of the He supply line hole  816  is a cavity  818 . In this embodiment, the cavity  818  is T-shaped. Partially filling the cavity  818  is a dielectric multilumen plug  820 . In this embodiment, the dielectric multilumen plug  820  comprises a central core  840  and an outer plug  844 . A cylindrical gap  822  is between the central core  840  and the outer plug. The central core has an upside-down T-shape with a flange attached to the outer plug  844 . To facilitate He passage into the cylindrical gap  822 , there are multiple openings or cutouts in the flange of the central core  840 . The cylindrical gap  822  extends to a first plenum  824 . Lumens  828  are formed to pass through the outer plug  844 , as shown. A top surface of the central core  840  is spaced apart from a surface of a central cavity in the outer plug  844  to provide a space forming the first plenum  824 . 
     A plurality of lumens  828  extends from the first plenum  824  to a second plenum  832  adjacent to a surface of the dielectric multilumen plug  820 . In this example, the dielectric multilumen plug  820  has 30 to 500 lumens  828 , where each lumen  828  has a diameter of between 1 micron and 150 microns. The plurality of lumens  828  may be placed to form concentric circles. On a second side of the second plenum  832 , opposite from the first side, is at least one He hole  836  that extends from the second plenum  832  to a surface of the ceramic plate  808 . In this example, the at least one He hole  836  has a diameter of between 0.2 to 0.3 mm. A slit  848  at the bottom of the central core  840  allows gas to pass from the He supply line hole  816  to the cylindrical gap  822 . 
     The dielectric multilumen plug  820  is T-shaped. In this embodiment, the top of the T-shaped dielectric multilumen plug  820  is bonded to the top of the T-shaped cavity  818  of the base plate  804 . A gap is between the bottom of the T-shaped dielectric multilumen plug  820  and the T-shaped cavity  818  to reduce arcing. In this embodiment, the gap is between 0.1 mm and 1 mm. The lumens  828  are be located away from the cylindrical gap  822  to avoid a direct line of sight from the top of the dielectric multilumen plug  820  to its bottom. 
       FIG. 9  is a schematic cross-sectional view of a spark suppression apparatus in part of an ESC  900  that may be used in another embodiment. In this embodiment, the ESC  900  comprises a base plate  904  bonded to a ceramic plate  908  by a bond layer  912 . In this embodiment, the base plate  904  is a conductive metal base plate  904 . The base plate  904  has a He supply line hole  916 . At an output end of the He supply line hole  916  is a cavity  918 . In this embodiment, the cavity  918  is T-shaped. Partially filling the cavity  918  is a dielectric multilumen plug  920 . A cylindrical groove  922  is formed in the dielectric multilumen plug  920  extending from the bottom of the dielectric multilumen plug  920  towards the top of the dielectric multilumen plug  920 . The cylindrical groove  922  forms a first plenum. Lumens  928  are formed to pass from the cylindrical groove  922  to the top of the dielectric multilumen plug  920  and to a second plenum  932  adjacent to a surface of the dielectric multilumen plug  920 . In this example, the dielectric multilumen plug  920  has 30 to 500 lumens  928 , where each lumen  928  has a diameter of between 1 micron and 150 microns. The plurality of lumens  928  may be placed to form concentric circles. On a second side of the second plenum  932 , opposite from the first side, is at least one He hole  936  that extends from the second plenum  932  to a surface of the ceramic plate  908 . In this example, the at least one He hole  936  has a diameter of between 0.02 to 0.3 mm. The He supply line hole  916  and the at least one He hole  936  form a helium line, wherein the He supply line hole  916  is a first portion of the He line and the at least one He hole  936  is a second portion of the He line. 
     The dielectric multilumen plug  920  is T-shaped. In this embodiment, the top of the T-shaped dielectric multilumen plug  920  is bonded to the top of the T-shaped cavity  918  of the base plate  904 . A gap is between the bottom of the T-shaped dielectric multilumen plug  920  and the T-shaped cavity  918  to reduce arcing. In this embodiment, the gap is between 0.1 mm and 1 mm. 
     Other embodiments may have different combinations of various features of the different embodiments. For example, a dielectric multilumen plug, such as the second dielectric multilumen plug  528  and third plenum  532  of the embodiment shown in FIG. 5  may be formed in the ceramic plates  608 ,  708 ,  808 , and  908  of the embodiments shown in  FIG. 6 ,  FIG. 7 ,  FIG. 8 , and  FIG. 9 . 
       FIG. 10  is a schematic view of an embodiment of a semiconductor processing chamber  1000  that may be used for processing a semiconductor wafer. In one or more embodiments, a semiconductor processing chamber  1000  comprises a gas distribution plate  1006  providing a gas inlet and an electrostatic chuck (ESC)  1008 , within an etch chamber  1049 , enclosed by a chamber wall  1052 . Within the etch chamber  1049 , a wafer  1003  is positioned over the ESC  1008 . The ESC  1008  is a wafer support. An edge ring  1009  surrounds the ESC  1008 . An ESC source  1048  may provide a bias to the ESC  1008 . A gas source  1010  is connected to the etch chamber  1049  through the gas distribution plate  1006 . An ESC He source  1050  is connected to the ESC  1008 . 
     A radio frequency (RF) source  1030  provides RF power to a lower electrode, an upper outer electrode  1016 , and an upper inner electrode. In this embodiment, the ESC  1008  is the lower electrode and the gas distribution plate  1006  is the upper inner electrode. In an exemplary embodiment, 400 kilohertz (kHz), 60 megahertz (MHz), 2 MHz, 13.56 MHz, and/or 27 MHz power sources make up the RF source  1030  and the ESC source  1048 . In this embodiment, one generator is provided for each frequency. In other embodiments, the generators may be separate RF sources, or separate RF generators may be connected to different electrodes. 
     Other arrangements of RF sources and electrodes may be used in other embodiments. In other embodiments, an electrode may be an inductive coil. 
     A controller  1035  is controllably connected to the RF source  1030 , the ESC source  1048 , an exhaust pump  1020 , and the gas source  1010 . A high flow liner  1004  is a liner within the etch chamber  1049 . The high flow liner  1004  in this embodiment is a C-shroud and confines gas from the gas source and has slots  1002 . The high flow liner  1004  allows for a controlled flow of gas to pass from the gas source  1010  to the exhaust pump  1020 . 
     During processing, He gas may be provided from the ESC He source  1050  to the backside of the ESC  1008  to provide heat transfer. The RF source  1030  provides power to form a plasma. The plasma may cause arcing. The arcing could pass towards the He source and damage the ESC  1008 . The above embodiment reduces arcing and therefore reduces ESC  1008  damage. 
     While this disclosure has been described in terms of several embodiments, there are alterations, modifications, permutations, and various substitute equivalents, which fall within the scope of this disclosure. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present disclosure. It is therefore intended that the following appended claims be interpreted as including all such alterations, modifications, permutations, and various substitute equivalents as fall within the true spirit and scope of the present disclosure.