Abstract:
An RF feed for a processing apparatus is disclosed. Coupling an RF generator to an RF matching network by a rigid RF feed lessens the amount of power that is lost during transmission from the generator to the matching network. The rigid RF feed comprises an inverted J shaped section that decouples the generator from the matching network whenever servicing the chamber is necessary. The J shape section has two parallel portions coupled together by a perpendicular portion. The J shaped section may be removed as a one piece assembly by uncoupling the J shaped section at a location disposed near the top of the chamber and a location near the floor of the chamber. The connections between the J shaped section and the remainder of the RF feed face the same direction to ensure easy coupling and decoupling without twisting and/or bending any portion of the rigid RF feed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/892,118 (APPM/11906L), entitled “Rigid RF Transmission Line with Easy Removal Section”, filed Feb. 28, 2007, which is herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the present invention generally relate to a rigid radio frequency (RF) feed from an RF generator to a matching network. 
         [0004]    2. Description of the Related Art 
         [0005]    Large area substrates may be used to fabricate such items as flat panel displays and solar panels. These substrates may exceed 2 square meters in surface area. One deposition method used to deposit material onto large area substrates is plasma enhanced chemical vapor deposition (PECVD). In a PECVD chamber, RF power may be supplied to the chamber through an RF matching network. The RF power may be generated remove from the PECVD chamber at an RF generator. Thus, there is a need in the art for an RF feed to deliver RF power from an RF generator to an RF matching network. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention generally relates to an RF feed for a processing apparatus. Coupling an RF generator to an RF matching network by a rigid RF feed lessens the amount of power that is lost during transmission from the generator to the matching network. The rigid RF feed comprises an inverted J shaped section that easily decouples the generator from the matching network whenever servicing the chamber is necessary. The J shape section has two parallel portions coupled together by a perpendicular portion. The J shaped section may be removed as a one-piece assembly by uncoupling the J shaped section at two locations. One location is disposed near the top of the chamber and the other location is near the floor of the chamber. The connections between the J shaped section and the remainder of the RF feed face the same direction to ensure easy coupling and decoupling without twisting and/or bending any portion of the rigid RF feed. 
         [0007]    In one embodiment, a power source for a processing chamber is disclosed. The power source comprises a power generator, a power input coupled with the processing chamber, and a rigid feed coupling the power generator to the power input. The feed line may have at least one inverted J shaped portion. 
         [0008]    In another embodiment, a plasma apparatus is disclosed. The apparatus comprises a lid assembly, an RF matching network disposed on the lid assembly, an RF generator, and a rigid RF feed line coupled between the RF matching network and the RF generator. 
         [0009]    In another embodiment, a method of connecting a power supply to a processing chamber is disclosed. The method may comprise lowering a rigid RF feed line into contact with both a power supply and a matching network. The RF feed may comprise two substantially parallel portions and a portion substantially perpendicular to the two substantially parallel portions. The method may also comprise connecting a first end of the rigid RF feed to a power supply and connecting a second end of the rigid RF feed to a matching network. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0010]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0011]      FIG. 1  is a perspective view of a system having a rigid RF feed coupled to one of the processing chambers according to one embodiment of the invention. 
           [0012]      FIG. 2  is a side view of the processing chamber of  FIG. 1  having the rigid RF feed coupled thereto. 
           [0013]      FIG. 3  is a backside view of the processing chamber of  FIG. 1  having the rigid RF feed coupled between an RF generator and an RF matching network. 
           [0014]      FIG. 4  is a perspective view of a rigid RF feed coupled between a matching network and an RF generator according to one embodiment of the invention. 
           [0015]      FIG. 5  is a schematic view of the inverted J section of the RF feed of  FIG. 4  disconnected according to one embodiment of the invention. 
           [0016]      FIG. 6A  is a cross sectional view of a coupling for a rigid RF feed according to one embodiment of the invention. 
           [0017]      FIG. 6B  is a cross sectional view of the coupling shown in  FIG. 6A  with the coupling uncoupled. 
       
    
    
       [0018]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
       DETAILED DESCRIPTION  
       [0019]    The present invention relates to an RF feed for a processing apparatus. While the invention will be described below in relation to a PECVD chamber available from AKT, a subsidiary of Applied Materials, Inc., Santa Clara, Calif., it is to be understood that the invention is equally applicable to any chamber that may require an RF feed to supply power to a matching network from an RF generator including physical vapor deposition (PVD) chambers. It is also to be understood that the invention described below is equally applicable to PECVD chambers and other chambers made by other vendors. 
         [0020]      FIG. 1  is a perspective view of a processing system  100  having a rigid RF feed coupled to one of the processing chambers  104  according to one embodiment of the invention. The processing system  100  shown in  FIG. 1  is an example of a cluster tool in which a plurality of processing chambers  104  surround a central transfer chamber  102 . One or more load lock chambers  106  may also be coupled to the transfer chamber  102 . Each of the processing chambers  104  and the load lock chamber  106  may be elevated off of the ground by a support frame  112  that matches the elevation of the slots of the transfer chamber  102  to the slots of the processing chambers  104  and the load lock chamber  106 . The slots are the openings through which substrates pass when they are moved between chambers  102 ,  104 ,  106 . 
         [0021]    Adjacent processing chambers  104  and load lock chambers  106  may be separated by platforms  108 . A platform permits a technician to access the top of the processing chambers  104  and the load lock chamber  106 . A platform  108  may be disposed between each adjacent chamber  104 ,  106  and stands at about one half the height of the processing chamber  104 . The platforms  108  may be accessed by a ladder  110  or staircase or any other suitable means for accessing an elevated surface. 
         [0022]    The processing chambers  104  may be any type processing chamber such as a PECVD chamber, a PVD chamber, or any other suitable processing chamber. The processing chambers  104  may be used to process any type of substrate such as a semiconductor substrate, a flat panel display substrate, a solar panel substrate, etc. The controllers  120  necessary for controlling the processes performed in the processing chambers  104  may be disposed under the processing chambers  104  and within the support frame  112 . 
         [0023]    For some processes, an RF power may need to be applied. In some situations, the RF power may be used to generate a plasma. In other situations, RF power may be used for heating. When RF power is applied to generate a plasma, the RF power may be generated in an RF generator  116  and pass through an RF feed  118  to a matching network  114 . The RF generator  116  may be disposed below the platform  108 . By disposing the RF generator  116  under the platform  108 , the distance that the RF power must travel from the RF generator  116  to the RF matching network  114  is as short as possible. By having as short a distance as possible between the RF generator  116  and the matching network  114 , the amount of power lost during transmission from the RF generator  116  to the RF matching network  114  may be minimized. To ensure as short as distance as possible is utilized, the RF feed  118  may be positioned to travel through an opening  122  within the platform  108 . In one embodiment length of the RF feed  118  between the RF generator  116  and the RF matching network  114  is about twenty feet. 
         [0024]      FIG. 2  is a side view of the processing chamber  104  of  FIG. 1  having the rigid RF feed  118  coupled thereto.  FIG. 3  is a backside view of the processing chamber of  FIG. 1  having the rigid RF feed coupled between an RF generator  116  and an RF matching network  114 . The RF generator  116  may be grounded through legs  206 . The RF feed  118  has a plurality of couplings  204   a  along the length of the RF feed  118 . In one embodiment, the couplings  204   a  may be fastened together by a one-way coupling mechanism. The one way coupling mechanism may be any known coupling mechanism that permits two items, in this embodiment two RF feed sections, to be joined together while making it difficult, if not impossible, to uncouple the items. The couplings  204   a  are one-way coupling mechanisms to discourage a technician from uncoupling the RF feed  118  at the couplings  204   a.    
         [0025]    Couplings  204   b , on the other hand, may be fastened together by a coupling mechanism that permits easy coupling and uncoupling. In one embodiment, the couplings  204   b  may comprise a nut and bolt assembly. The couplings  204   b  encourage a technician to uncouple the RF feed  118  and the couplings  204   b  rather than at the one way couplings  204   a.    
         [0026]    One of the couplings  204   b  may be disposed just above the level of the platform  108 . In one embodiment, the coupling  204   b  may be about five inches above the platform  108 . The other coupling  204   b  may be disposed above the lid  202  of the processing chamber  104 . As may be seen in  FIG. 2 , the portion of the RF feed  118  between the couplings  204   b  is substantially the shape of an inverted “J”.  FIG. 3  shows that the vertical portions of the RF feed  188  are aligned along parallel axis so that whenever couplings  204   b  are uncoupled, the inverted “J” portion of the RF feed  118  may be removed by raising the inverted “J” portion. By simply raising the inverted “J” portion of the RF feed  118 , no bending of the RF feed  118  is necessary. Hence, the RF feed  118  may be a rigid structure that is not substantially deformable. Conversely, if couplings  204   a  are uncoupled, there is an increased likelihood of bending and hence, breaking of the RF feed  118 . When the couplings  204   b  are uncoupled and the inverted “J” portion is removed, the lid  202  of the processing chamber  104  may be removed without damaging the RF feed  118 . 
         [0027]      FIG. 4  is a perspective view of a rigid RF feed coupled between a matching network  404  and an RF generator  402  according to one embodiment of the invention. The system  400  comprises a plurality of tubes  410 ,  412 ,  414 ,  416 ,  418 ,  420 ,  422 ,  424 ,  426  coupled together by couplings  406 ,  408 . The couplings  406  are one way couplings that couple some of the tubes  410 ,  412 ,  414 ,  416 ,  418 ,  420 ,  422 ,  424 ,  426  together. Couplings  408  are couplings that permit easy coupling and uncoupling of tubes  414 ,  416  and easy coupling and uncoupling of tubes  422 ,  424 . By uncoupling tubes  414 ,  416  and uncoupling tubes  422 ,  424 , an inverted “J” section of the RF feed is uncoupled. The inverted “J” section comprises two parallel portions and another portion perpendicular to the parallel portions. The vertical portion of the elbow tube  422  is parallel to tube  416 . Tube  420  is perpendicular to both tube  416  and the vertical portion of elbow tube  422 . Hence, tubes  416 ,  418 ,  420 , and  422  form an inverted “J” shaped section of the RF feed. 
         [0028]      FIG. 5  is a schematic view of the inverted “J” section of the RF feed of  FIG. 4  disconnected according to one embodiment of the invention. One end  502  of tube  416  has been uncoupled from one end  504  of tube  414 . Additionally, one end  506  of tube  424  has been uncoupled from one end  508  tube  422 . The end  508  of elbow tube  422  may be at a different elevation than the end  502  of tube  416 . Thus, while tube  416  and the vertical portion of elbow tube  422  are parallel, the ends  502 ,  508  are at different elevations. 
         [0029]      FIG. 6A  is a cross sectional view of a coupling  600  for a rigid RF feed according to one embodiment of the invention. In  FIG. 6A , an upper section  622  of the RF feed is coupled to a lower section  624  of the RF feed. The upper and lower sections  622 ,  624  each comprise an outer tube  602  and an inner wire  610 . It is to be understood that while the inner wire  610  is described as a wire, any suitable mechanism capable of transmitting RF current there through may be utilized. The outer tube  602  may comprise copper and provides a return path to ground for the RF feed. The outer tube  602  may be separated from the wire  610  by a space  612 . In one embodiment, the space  612  may comprise air. The air between the outer tube  602  and the wire  610  acts as a dielectric to prevent loss of power along the RF feed between an RF generator and an RF matching network. The wire  610  may be centered within the space  612  within the outer tube  602 . 
         [0030]    At the ends of the sections  622 ,  624 , the wires  610  may be coupled with the outer tube  602  by an electrically insulating coupler  614 . Thus, the only direct connection between the outer tube  602  and the wire  612  occurs at the electrically insulating coupler  614 . The electrically insulating coupler  614  may be disposed at the coupling  600 . Flanges  604  may extend from the outer tube  602  at the coupling  600 . A fastening mechanism may be disposed through the flanges  604  to couple the upper section  622  to the lower section  624 . In one embodiment, the fastening mechanism comprises a bolt  606  and nut  608  assembly. 
         [0031]      FIG. 6B  is a cross sectional view of the coupling  600  shown in  FIG. 6A  with the coupling uncoupled. As may be seen in  FIG. 6B , a passage  620  may be present within the flange  604  to permit the fastening mechanism to couple the upper section  622  and lower section  624  together. The wires  610  may be coupled together by a male connector  618  extending from the upper section  622  connected into a female receiver  616  disposed in the lower section  624 . In one embodiment, the male connector  618  may be disposed in the lower section  624  and the female receiver  618  may be disposed in the upper section  622 . The coupling  600  may be used as the couplings  408  and  204   b  shown in  FIGS. 2-5 . Both ends of the inverted J section should have the same connection at each end. For example, both ends of the inverted J section may comprise a male connector  618 . Alternatively, both ends of the J section may comprise a female receiver  616 . 
         [0032]    To prevent the wires  610  from uncoupling during the uncoupling of the inverted “J” section from the RF feed, the electrically insulating coupler  614  may be fixedly attached to both the wire  610  and the outer tube  602 . In one embodiment, the electrically insulating coupler  614  may be soldered to the wire  610  and to the outer tube  602 . Care should be taken when soldering the electrically insulating coupler  614  to the wire  610  and the outer tube  602  to ensure that the soldering locations do not touch. If the soldering locations touch, then the outer tube  602  and the wire  610  will be electrically coupled together and thus, the outer tube  602  may have an active current passing there through. Alternatively, if the outer tube  602  and the wire  610  are electrically coupled together, power may be lost between the RF generator and the RF matching network. 
         [0033]    A rigid RF feed having a removable inverted “J” shaped section reduces the amount of power that may be lost between the RF generator and the RF matching network, permits easy coupling and uncoupling of the RF generator to the processing chamber, and shortens the distance between the RF generator and the RF matching network. 
         [0034]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.