Patent Publication Number: US-8119532-B2

Title: Inductively coupled dual zone processing chamber with single planar antenna

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional application of U.S. application Ser. No. 11/819,898, now U.S. Pat. No. 7,972,471, entitled INDUCTIVELY COUPLED DUAL ZONE PROCESSING CHAMBER WITH SINGLE PLANAR ANTENNA, filed on Jun. 29, 2007, the entire content of which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     Plasma processing apparatuses are used to process substrates by techniques including etching, physical vapor deposition (PVD), chemical vapor deposition (CVD), ion implantation, and resist removal. One type of plasma processing apparatus used in plasma processing includes an external induction antenna. An electromagnetic field is generated in the chamber underlying the antenna to excite a process gas into the plasma state to process substrates in the reaction chamber. 
     SUMMARY 
     A dual zone plasma processing chamber is provided. The plasma processing chamber includes a first substrate support having a first support surface adapted to support a first substrate within the processing chamber and a second substrate support having a second support surface adapted to support a second substrate within the processing chamber. One or more gas sources in fluid communication with one or more gas distribution members supply process gas to a first zone adjacent to the first substrate support and a second zone adjacent to the second substrate support. A radio-frequency (RF) antenna adapted to inductively couple RF energy into the interior of the processing chamber and energize the process gas into a plasma state in the first and second zones. The antenna is located between the first substrate support and the second substrate support. 
     A method of simultaneously processing first and second semiconductor substrates in a plasma processing chamber is provided. A first substrate is placed on a first substrate support and a second substrate on the second substrate support in the dual zone plasma processing chamber. Process gases from the one or more gas sources are discharged into the first zone between the antenna and the first substrate and into the second zone between the antenna and the second substrate. A first plasma is generated from the first process gas in the first zone. A second plasma is generated from the second process gas in the second zone. The first substrate is processed with the first plasma and the second substrate is processed with the second plasma. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a cross-sectional view of an inductively coupled plasma processing apparatus for processing a single substrate. 
         FIG. 2  is a cross-sectional view of an inductively coupled dual zone plasma processing apparatus for processing two vertically spaced apart substrates in a horizontal configuration under the same processing conditions. 
         FIG. 3  is a cross-sectional view of an inductively coupled plasma processing apparatus for processing two horizontally spaced apart substrates in a vertical configuration under the same processing conditions. 
         FIG. 4  is a cross-sectional view of an inductively coupled plasma processing apparatus for processing two vertically spaced apart substrates in a horizontal configuration under different processing conditions. 
     
    
    
     DETAILED DESCRIPTION 
     Inductively coupled plasma processing chambers are generally used for depositing (e.g., plasma enhanced chemical vapor deposition or PECVD) and plasma etching of materials on substrates by supplying process gas into a vacuum chamber at a low pressure (i.e., below 50 mTorr) and the application of radio-frequency (RF) energy to the gas. The substrates can be held in place within the vacuum chamber during processing by substrate holders including mechanical clamps and electrostatic clamps (ESC). For inductively coupled plasma (ICP) systems, an RF antenna is located outside the process chamber and the RF energy is inductively coupled into the chamber through a dielectric window. Such processing systems can be used for a variety of semiconductor processing applications such as etching, deposition, or resist stripping. 
       FIG. 1  is a cross-sectional view of an embodiment of an ICP plasma processing chamber  10 . An example of an ICP plasma processing chamber is the TCP® etch or deposition system, manufactured by Lam Research Corporation, Fremont, Calif. The ICP plasma processing chamber is also described, for example, in commonly-owned U.S. Pat. No. 4,948,458, which is incorporated by reference in its entirety. Processing chamber  10  includes a substrate support  12  with support surface  14 . The support surface  14  is adapted to support substrate  16 . A vacuum pump  18  is attached to pump port  20  to maintain the interior processing chamber  10  at a low pressure (e.g., between about 1 mTorr to about 50 mTorr). A gas source  22  supplies process gases to the interior of processing chamber  10  through a gas distribution plate, showerhead arrangement, injector or other suitable arrangement. Process gases can be introduced by the gas distribution member  24  to a zone adjacent to substrate  16 . 
     Once process gases are introduced into the interior of processing chamber  10 , they are energized into a plasma state by an energy source supplying energy into the interior of the processing. chamber  10 . Preferably, the energy source is an external planar antenna  26  powered by an RF source  28  and RF impedance matching circuitry  30  to inductively couple RF energy into processing chamber  10 . An electromagnetic field generated by the application of RF power to planar antenna  26  energizes the process gas to form a high-density plasma  30  (e.g., 10 11 -10 12  ions/cm 3 ) above substrate  16 . 
     A dielectric window  32  underlies planar antenna  26  and forms the top wall of plasma processing chamber  10 . The gas distribution member  24  is placed below dielectric window  32 . High-density plasma  30  is generated in the zone between gas distribution member  24  and substrate  16 , for either deposition or etching of substrate  16 . 
     In order to increase production efficiency while minimizing power requirements, described herein is a novel dual zone plasma processing chamber which can simultaneously process two substrates on opposite sides of a single planar antenna. One approach for maximizing the symmetrical electromagnetic fields generated by planar antenna  18  is the dual-zone configuration of the  FIG. 2  embodiment.  FIG. 2  is a cross-sectional view of an embodiment of a dual-zone ICP plasma processing chamber  100 , including zones  110 ,  210 . Zones  110 ,  210  of processing chamber  100  include the spaces between dielectric windows  132 ,  232  and substrate supports  112 ,  212  with horizontal support surfaces  114 ,  214 , respectively. Support surfaces  114 ,  214  are adapted to support substrates  116 ,  216  in a horizontal position. Substrate supports  112 ,  212  can be supported in a cantilever manner by support arms extending from the chamber walls and are diametrically opposite one another in processing chamber  100 . 
     Vacuum pumps  118 ,  218  are attached to pump ports  120 ,  220  to maintain the interior of processing chamber  100  at a low pressure (e.g., between about 1 mTorr to about 50 mTorr). Pump ports  120 ,  220  are adjacent to substrate supports  120 ,  220  and can be diametrically opposite one another in processing chamber  100 . 
     Common gas source  122  supplies process gases to the interior of processing chamber  100  to zones  110 ,  210 . Process gases can be introduced into any suitable gas distribution arrangement, e.g. a dual-ended gas injector or distribution member  124  adjacent to substrates  116 ,  216 , respectively. Use of the common gas source  122  and gas distribution members  124  ensure delivery of the same gas compositions to zones  110  and  210 . The gas distribution arrangement can include two gas distribution members (e.g., gas distribution rings, gas distribution plates or gas injection nozzles) in fluid communication with one another and connected by a common passage  125 , extending through an opening in dielectric windows  132 ,  232 . Such gas distribution members are also described, for example, in commonly-owned U.S. Pat. Nos. 6,184,158 and 6,230,651, which are incorporated by reference in their entirety. The location of pump ports  120 ,  220  and vacuum pumps  118 ,  218  at opposite ends of the chamber  100  facilitates distribution of the process gas uniformly across the surfaces of substrates  116 ,  216 . 
     Substrates  116 ,  216  are held in place on substrate supports  112 ,  212 . The substrate supports can include electrostatic chucks (ESC), mechanical clamps, or other clamping mechanisms. Such substrate supports are also described, for example, in commonly-owned U.S. Pat. Nos. 5,262,029 and 5,838,529, which are incorporated by reference in their entirety. Substrate supports  112 ,  212  can also include an RF biasing electrode (not shown). For temperature control of the substrates  116 ,  216 , the substrates  116 ,  216  can be cooled by flowing helium gas beneath the substrate and the substrate supports  112 ,  212  can be liquid cooled (not shown). Such temperature control is described in commonly owned U.S. Pat. No. 6,140,612, which is incorporated by reference in its entirety. 
     Once process gases are introduced into the interior of processing zones  110 ,  120 , they are energized into a plasma state by a single external planar antenna  126  which supplies RF energy in opposite directions into zones  110 ,  120  in the interior of the processing chamber  100 . The external planar antenna  126  is powered by a single RF source  128  and RF impedance matching circuitry  130  to inductively couple RF energy into processing chamber  100 . The symmetric electromagnetic field generated above and below planar antenna  126  by the application of RF power energizes the process gases to form high-density plasmas  130 ,  230  (e.g., 10 11 -10 12  ions/cm 3 ) in zones vertically adjacent to substrates  116 ,  216 . The configuration of processing chamber  100  has the potential of doubling the substrate processing throughput within the footprint of a chamber used for single substrate processing and without the expenditure of additional RF energy which would be required for running two processing chambers. 
     The single external planar antenna  126  can comprise one or more planar spiral coils or other configurations such as a series of concentric rings. A planar coil can be scaled-up by employing a longer conductive element to increase the antenna diameter and therefore accommodate larger substrates such as 300 mm wafers or multiple coils arranged in a planar array could be used to generate a uniform plasma over a wide area, such as for flat panel display processing. 
     The external planar antenna  126  is located in a space  134  which is at ambient pressure (i.e., atmospheric pressure). The space  134  is between dielectric window  132  and dielectric window  232 . Dielectric windows  132 ,  232  can be composed of any dielectric material that is transparent to RF energy, such as quartz. Dielectric window  132  underlies planar antenna  126  and forms an upper wall relative to zone  110 . Likewise, dielectric window  232  overlies planar antenna  126  and forms a lower wall relative to zone  210 . In one embodiment, space  134  is enclosed in a metallic compartment supporting dielectric windows  132 ,  232  as walls of the compartment. 
     When substrates  116 ,  216  are processed in processing chamber  100 , the RF source  128  supplies the antenna  126  with RF current preferably at a range of about 100 kHz-27 MHz, and more preferably at 13.56 MHz. 
       FIG. 3  is a cross-sectional view of another embodiment of a dual-zone ICP plasma processing chamber  300 , including zones  310 ,  410 . Other than the orientation of the processing chamber  100 , the configuration of plasma processing chamber  300  is similar to the plasma processing chamber  100  in  FIG. 2 . Zones  310 ,  410  of processing chamber  300  include the spaces between dielectric windows  332 ,  432  and substrate supports  312 ,  412  with vertical support surfaces  314 ,  414 , respectively. Support surfaces  314 ,  414  are adapted to support substrates  316 ,  416  in a vertical position. Substrate supports  312 ,  412  are preferably diametrically opposite one another in processing chamber  300 . Vacuum pumps  318 ,  418  are attached to pump ports  320 ,  420  to maintain the interior of processing chamber  300  at a low pressure (e.g., between about 1 mTorr to about 50 mTorr). Pump ports  320 ,  420  are adjacent to substrate supports  312 ,  412  and are preferably diametrically opposite one another in processing chamber  300 . 
     Common gas source  322  supplies process gases to the interior of processing chamber  300 . Process gases can be introduced into any suitable gas distribution arrangement, e.g. a dual-ended gas injector or distribution member  324  adjacent to substrates  316 ,  416 , respectively. The gas distribution arrangement can include two gas distribution members (e.g., gas distribution rings, gas distribution plates or gas injection nozzles) in fluid communication with one another and connected by a common passage  325 , extending through an opening in dielectric windows  332 ,  432 . 
     Substrates  316 ,  416  are held in place on substrate supports  312 ,  412 . The substrate supports can include electrostatic chucks (ESC), mechanical clamps, or other clamping mechanisms. Substrate supports  312 ,  412  can also include an RF biasing electrode (not shown). For temperature control of the substrates  316 ,  416 , the substrates  316 ,  416  can be cooled by flowing helium gas beneath the substrates and the substrate supports  316 ,  416  can be liquid cooled (not shown). 
     Once process gases are discharged into the interior of processing zones  310 ,  410 , they are energized into a plasma state by a single antenna arrangement supplying energy into the interior of the processing chamber  300 . Preferably, the energy source is an external planar antenna  326  powered by an RF source  328  and RF impedance matching circuitry  330  to inductively couple RF energy into processing chamber  300 . The symmetric electromagnetic field generated by planar antenna  326  through the application of RF power energizes the process gas to form high-density plasmas  330 ,  430  (e.g., 10 11 -10 12  ions/cm 3 ), laterally adjacent to substrates  316 ,  416 . Similar to processing chamber  100  of  FIG. 2 , the configuration of processing chamber  300  has the potential of doubling the substrate processing throughput without the expenditure of additional RF energy. 
     The external planar antenna  326  is supported in space  334  which is at ambient pressure between dielectric window  332  and dielectric window  432 . Dielectric windows  332 ,  432  can be composed of any dielectric material that is transparent to RF energy, such as quartz. Dielectric window  332  is laterally adjacent to planar antenna  326  and forms a side wall relative to zone  310 . Likewise, dielectric window  432 , also laterally adjacent to planar antenna  326 , forms a side wall relative to zone  410 . In one embodiment, space  334  is enclosed in a metallic compartment supporting dielectric windows  332 ,  432  as walls of the compartment. 
       FIG. 4  is a cross-sectional view of another embodiment of a dual-zone ICP plasma processing chamber having sub-chambers  500 ,  600 , including zones  510 ,  610 , to simultaneously process two substrates under different processing conditions. Similar to the  FIG. 2  embodiment, the configuration of processing sub-chambers  500 ,  600  includes horizontal support surfaces  514 ,  614 . 
     Zones  510 ,  610  of sub-chambers  500 ,  600  include the spaces between dielectric windows  532 ,  632  and substrate supports  512 ,  612  with horizontal support surfaces  514 ,  614 , respectively. Support surfaces  514 ,  614  are adapted to support substrates  516 ,  616  in a horizontal position. Substrate supports  512 ,  612  can be diametrically opposite one another. Vacuum pumps  518 ,  618  are attached to pump ports  520 ,  620  to maintain the interior of processing chamber  300  at a low pressure (e.g., between about 1 mTorr to about 50 mTorr). Pump ports  520 ,  620  are adjacent to substrate supports  512 ,  612  and can be diametrically opposite one another. 
     Gas sources  522 ,  622  supply process gases to the interior of processing chamber  300 . Process gases can be introduced into the gas distributions members  524 ,  624  adjacent to substrates  516 ,  616 . If substrates  516 ,  616  are subjected to different plasma processing conditions, gas sources  522 ,  622  can supply different gas recipes. For example, substrate  516  can undergo an etching process, while substrate  616  undergoes a chemical vapor deposition process and vice versa. Examples of etching processes include conductor etching, dielectric etching or photoresist stripping. Examples of deposition processes include the chemical vapor deposition of dielectric or conductive films. Gas distribution member  524 ,  624  can include gas distribution rings, gas distribution plates or gas injection nozzles. The process gases in zones  510 ,  610  are energized upon supplying RF energy to planar antenna  526 , forming plasmas  530 ,  630  for the plasma processing of substrates  516 ,  616 . 
     If different process gases from gas sources  522 ,  622  are used to generate plasmas  530 ,  630 , it becomes necessary to isolate processing sub-chambers  500 ,  600  with partition  536 . Because different gas chemistries are used to generate plasmas  530 ,  630  and produce different by-products, in the absence of partition  536 , the different process gases released from gas distribution members  524 ,  624  and by-products of the processing may diffuse towards unintended regions of the processing chambers  500 ,  600 , rather than uniformly over the surface of substrates  516 ,  616 . 
     Substrates  516 ,  616  are held in place on substrate supports  512 ,  612 . The substrate supports can include electrostatic chucks (ESC), mechanical clamps, or other clamping mechanisms. Substrate supports  512 ,  612  can also include an RF biasing electrode (not shown). For temperature control of the substrates  516 ,  616 , the substrates  516 ,  616  can be cooled by flowing helium gas beneath the substrates and the substrate supports  516 ,  616  can be liquid cooled (not shown). 
     Once process gases are discharged into the interior of processing zones  510 ,  610 , they are energized into a plasma state by a single antenna arrangement supplying energy into the interior of the processing chambers  500 ,  600 . Preferably, the energy source is an external planar antenna  526  powered by an RF source  528  and RF impedance matching circuitry  530  to inductively couple RF energy into processing chambers  500 ,  600 . The symmetric electromagnetic field generated by planar antenna  526  through the application of RF power energizes the process gas to form high-density plasmas  530 ,  630  (e.g., 10 11 -10 12  ions/cm 3 ), laterally adjacent to substrates  516 ,  616 . Similar to processing chambers  200 ,  300  of  FIGS. 2 and 3 , the configuration of processing chambers  500 ,  600  has the potential of doubling the substrate processing throughput without the expenditure of additional RF energy. 
     The external planar antenna  526  is supported in space  534  which is at ambient pressure between dielectric window  532  and dielectric window  532 . Dielectric windows  532 ,  632  can be composed of any dielectric material that is transparent to RF energy, such as quartz. Dielectric window  532  is laterally adjacent to planar antenna  526  and forms a top wall relative to zone  510 . Likewise, dielectric window  632 , also laterally adjacent to planar antenna  526 , forms a bottom wall relative to zone  610 . In one embodiment, space  534  is enclosed in a metallic compartment supporting dielectric windows  532 ,  632  as walls of the compartment. 
     In another embodiment for simultaneously process two substrates under different processing conditions, the configuration of the processing sub-chambers to can include vertical support surfaces, similar to the  FIG. 3  embodiment. 
     While the invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made, and equivalents employed, without departing from the scope of the appended claims.