Abstract:
An arrangement for performing pressure control in a plasma processing chamber comprising an upper electrode, a lower electrode, a unitized confinement ring arrangement wherein the upper electrode, the lower electrode and the unitized confinement ring arrangement are configured at least for surrounding a confined chamber region to facilitate plasma generation and confinement therein. The arrangement further includes at least one plunger configured for moving the unitized confinement ring arrangement in a vertical direction to adjust at least one of a first gas conductance path and a second gas conductance path to perform the pressure control, wherein the first gas conductance path is formed between the upper electrode and the unitized confinement ring arrangement and the second gas conductance path is formed between the lower electrode and the single unitized ring arrangement.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional of and claims priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 12/890,990, filed Sep. 27, 2010, entitled “UNITIZED CONFINEMENT RING ARRANGEMENTS AND METHODS THEREOF”, which claims priority under 35 USC. 119(e) to U.S. Provisional Patent Application No. 61/246,526, filed on Sep. 28, 2009 all of which are incorporated herein by reference in their entirety for all purposes. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Advances in plasma processing have provided for growth in the semiconductor industry. In today&#39;s competitive market, the ability of a manufacturing company to be able to minimize waste and produce high quality semiconductor devices gives the manufacturing company a competitive edge. Accordingly, tight control of the process parameters is generally needed to achieve satisfactory results during substrate processing. Thus, manufacturing companies have dedicated time and resources to identify methods and/or arrangements for improving substrate processing. 
         [0003]    In a plasma processing system, such as a capacitively-coupled plasma (CCP) or an inductively-coupled plasma (ICP) processing system, the manufacturing of semiconductor devices may require multi-step processes employing plasma within a processing chamber. During processing, gas may interact with radio frequency (RF) power to form plasma. Confinement rings may be employed to control plasma formation and to protect the process chamber walls. The confinement rings may include multiple rings stacked on top of one another and are configured to surround the periphery of the chamber volume in which plasma is to form (i.e., confined chamber region). 
         [0004]    The confinement rings may also be employed to control the pressure level within the confined chamber region. Typically, during processing, the processing chamber is usually maintained at a predefined pressure for each process step in order to generate the desired plasma needed for processing the substrate. Those skilled in the arts are aware that a stable plasma is important during substrate processing. Thus, the ability to maintain tight control of the process parameters during substrate processing is essential for plasma stability. When the process parameters (e.g., pressure or other parameters) are outside of a narrow, pre-defined window, the process parameters may have to be adjusted to maintain a stable plasma in accordance with the required processing recipe. 
         [0005]      FIG. 1  shows a simple cross-sectional diagram of a confinement ring arrangement within a processing chamber. Consider the situation wherein, for example, a substrate  102  is disposed on top of a lower electrode  104  (such as an electrostatic chuck). During substrate processing, plasma  106  may form between substrate  102  and upper electrode  108 . Surrounding the plasma is a plurality of confinement rings ( 110   a ,  110   b ,  110   c ,  110   d , etc.), which may be employed to confine plasma  106  and to control the pressure within the confinement region (such as a confined chamber region  118 ). The gaps (such as gaps  112   a ,  112   b ,  112   c , etc.) between the plurality of confinement rings may be adjusted to control the exhaust rate, hence the pressure above the substrate surface. 
         [0006]    In a typical processing chamber that employs the plurality of confinement rings ( 110   a ,  110   b ,  110   c ,  110   d , etc.), the confinement rings may have attachment points. Positioned at each attachment point is a plunger (such as  114  and  116 , for example). To control the volume of pressure within confinement region  118 , a plunger controller module  120  (such as a CAM ring arrangement) may move the plungers vertically (up/down) to adjust the gaps between the plurality of confinement rings ( 110   a ,  110   b ,  110   c ,  110   d , etc.). By adjusting the gaps between the confinement rings, the conductance rate of gas being exhausted from the confined chamber region may be controlled, thereby controlling the amount of pressure within the processing chamber. In other words during substrate processing, if the chamber pressure is outside of the designated range (such as that determined by the current recipe step), the confinement rings may be adjusted. In an example, to increase the pressure within the processing chamber, the gaps between the confinement rings may be reduced. 
         [0007]    In a competitive market, the ability to simplify a process and/or components usually gives the manufacturing company a competitive edge over its competitors. In view of the increasingly competitive substrate processing market, a simple arrangement that provides for pressure control while confining plasma formation within the plasma generating region is desirable. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention relates, in an embodiment, to an arrangement for performing pressure control in a plasma processing chamber comprising an upper electrode, a lower electrode, a unitized confinement ring arrangement wherein the upper electrode, the lower electrode and the unitized confinement ring arrangement are configured at least for surrounding a confined chamber region to facilitate plasma generation and confinement therein. The arrangement further includes at least one plunger configured for moving the unitized confinement ring arrangement in a vertical direction to adjust at least one of a first gas conductance path and a second gas conductance path to perform the pressure control, wherein the first gas conductance path is formed between the upper electrode and the unitized confinement ring arrangement and the second gas conductance path is formed between the lower electrode and the single unitized ring arrangement. 
         [0009]    These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]    The present invention 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: 
           [0011]      FIG. 1  shows a simple cross-sectional diagram of a confinement ring arrangement within a processing chamber. 
           [0012]      FIGS. 2-5  show, in embodiments of the invention, cross-sectional views of different configurations of a single unitized confinement ring arrangement for performing pressure control and plasma confinement. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0013]    The present invention 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 invention. It will be apparent, however, to one skilled in the art, that the present invention 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 invention. 
         [0014]    Various embodiments are described hereinbelow, including methods and techniques. It should be kept in mind that the invention might also cover articles of manufacture that includes a computer readable medium on which computer-readable instructions for carrying out embodiments of the inventive technique are stored. The computer readable medium may include, for example, semiconductor, magnetic, opto-magnetic, optical, or other forms of computer readable medium for storing computer readable code. Further, the invention may also cover apparatuses for practicing embodiments of the invention. Such apparatus may include circuits, dedicated and/or programmable, to carry out tasks pertaining to embodiments of the invention. Examples of such apparatus include a general-purpose computer and/or a dedicated computing device when appropriately programmed and may include a combination of a computer/computing device and dedicated/programmable circuits adapted for the various tasks pertaining to embodiments of the invention. 
         [0015]    In accordance with embodiments of the present invention, a single or unitized (the terms are synonymous in the context of the present invention) confinement ring arrangement is provided for confining plasma and for controlling pressure within a plasma generating region. As the term is defined herein, a unitized confinement ring is a ring which may be formed of a single block of material, in one or more embodiments, or may comprise of multiple individually manufactured parts that are later assembled, in other embodiments. When the multiple parts are assembled to form the single unitized confinement ring, the various parts of the confinement are nonmovable relative to one another during deployment and retraction. This is unlike the prior art situation when the rings may expand and collapse during deployment and retraction. In an embodiment, the unitized ring may include one or more rings. 
         [0016]    Embodiments of the invention include a unitized confinement ring arrangement that may be implemented with different configurations, depending upon the requirement of the processing chamber. Embodiments of the invention also include an automatic feedback arrangement for monitoring and stabilizing the pressure within the plasma generating region. 
         [0017]    In an embodiment, a unitized confinement ring arrangement is provided for confining plasma and controlling the pressure within the plasma generating region. The confinement ring may surround the periphery of the processing chamber area in which plasma is to form (i.e., confined chamber region) to prevent plasma from escaping the confined chamber region and to protect the chamber wall. Generally, one or more paths (channels) are provided for exhausting gas (such as neutral gas species) from the confined chamber region. Since conductance rate of gas exhaust within the confined chamber region is usually a factor of the size and length of the path available for exhausting the gas from the plasma generating region, different arrangements may be provided for implementing a unitized confinement ring within the processing chamber, in an embodiment. 
         [0018]    In one embodiment, by moving the confinement ring vertically up/down, the size of the path may be reduced or expanded to change the conductance rate, thereby modifying the pressure within the confined chamber region. In an example, by moving the confinement ring downward, the gap between the bottom surface of the unitized confinement ring and the top surface of the bottom ground extension may be reduced. Thus, less gas may be exhausted from the confined chamber region, thereby increasing the pressure level within the plasma generating region. 
         [0019]    In another embodiment, the length of the path may also be adjusted when the confinement ring is moved vertically up/down. In an example, moving the confinement ring upward may cause the path between the left side wall of the confinement ring and the right side wall of the upper electrode to lengthen. A longer path usually creates more resistance to the gas flow. Thus, less gas is exhausted and the pressure within the confined chamber region is increased. 
         [0020]    Besides the size and length of the path, the number of paths available may also impact the overall conductance rate for exhausting gas from the confined chamber region. In an example, if two possible paths exist for exhausting gas from the confined chamber region, both paths may be considered in determining the overall conductance rate. This is especially true if one path provides a counter effect on the conductance rate of the other path. For example, an upper path and a lower path are available for exhausting gas from the confined chamber region. When the confinement ring is moved downward, the upper path is shortened (therefore reducing resistance to flow) while the lower path is reduced (thereby increasing resistance to flow). To calculate the overall conductance rate for the confined chamber region, the conductance rates for both of the upper path and the lower path may be considered. 
         [0021]    In an embodiment, one or more slots may be created in the unitized confinement ring to facilitate exhaust flow. The slots may be equal in length or may have different lengths. The slots may be equally or unequally spaced. The length and cross-sectional area of the slots may also vary. 
         [0022]    In an embodiment, a feedback arrangement may be provided for confining pressure and managing pressure control. The feedback arrangement may include a sensor configured for monitoring the pressure level within the confined chamber region. The data collected by the sensor is sent to a precision vertical movement arrangement for analysis. A comparison to a predefined threshold range may be performed. If the pressure level is outside of the threshold range, the confinement ring may be moved into a new position to change the pressure level locally within the confined chamber region. 
         [0023]    The features and advantages of the present invention may be better understood with reference to the figures and discussions that follow. 
         [0024]    Equation 1 below shows a simple equation illustrating the conductance of controllable gap. 
         [0000]      Conductance of controllable gap˜( C*D   n )/ L   [Equation 1]
 
         [0025]    C=constant (function of gas molecular weight, temperature, etc.) 
         [0026]    D=the width of the channel for evacuating the exhaust gas 
         [0027]    L=length of the channel for evacuating the exhaust gas 
         [0028]    n=number of channels (such as slots) for evacuating the exhaust gas 
         [0029]    As shown by Equation 1, the conductance rate of gas exhaust may be controlled by varying one of the variables (D, L, or n) above. The next few figures ( FIG. 2-FIG .  5 ) provides examples of different configurations for implementing a single unitized confinement ring in controlling at least one of plasma confinement and pressure control within a confined chamber region. 
         [0030]      FIG. 2  shows, in an embodiment of the invention, a simple diagram of a partial view of a processing chamber  200  with a unitized confinement ring arrangement for performing pressure control and/or plasma confinement. In an embodiment, processing chamber  200  may be a capacitively-coupled plasma processing chamber. 
         [0031]    In this document, various implementations may be discussed using a capacitively-coupled plasma (CCP) processing system as an example. This invention, however, is not limited to a CCP processing system and may include other processing system, such as an inductively-coupled plasma (ICP) processing system, that may exist. Instead, the discussions are meant as examples and the invention is not limited by the examples presented. 
         [0032]    During substrate processing, a plasma, which may be employed to etch a substrate, may form within a confined chamber region  204 . In order to control plasma formation and to protect the processing chamber parts, a unitized confinement ring  202  may be employed to surround the periphery of confined chamber region  204 , in an embodiment. In an embodiment, at least a portion of confinement ring  202  is generally cylindrical in shape and is positioned between an upper electrode  206  and a chamber wall  208 . In addition, a part of the width of confinement ring  202  is overlapping a bottom ground extension  210 . Confinement ring  202  may be made from a dielectric material or an RF ground conductive material, in an embodiment. In addition to the unitized confinement ring, the periphery of confined chamber region  204  may also be defined by an upper electrode  206 , the substrate disposed on the lower electrode, a bottom ground extension  210  and other chamber structures. 
         [0033]    During substrate processing, gas may flow from a gas distribution system (not shown) into confined chamber region  204  to interact with RF power to create plasma. In order to evacuate exhaust gas from the confinement region (confined chamber region  204 ), one or more exhaust paths are usually provided. In an example, the exhaust gas may be evacuated from confined chamber region  204  by flowing either along an upper path  212  or a lower path  214 . In an embodiment, the exhaust gas evacuation rate from confined chamber region  204  may be controlled by moving confinement ring  202  vertically (up/down). 
         [0034]    As shown by Equation 1 above, the conductance rate of gas exhaust may be controlled by varying one of the variables (D, L, or n). In an example, by moving confinement ring  202  vertically up/down, a gap  218  (D), which is the distance between the bottom surface of confinement ring  202  and the top surface of bottom ground extension  210  may be adjusted. In other words, by adjusting gap  218 , the rate of conductance may vary, thereby changing the pressure level (P w ) within confined chamber region  204 . For example, by reducing gap  218 , less gas is exhausted from confined chamber region  204 , thereby increasing the pressure level (P w ) within confined chamber region  204 . Conversely, by increasing gap  218 , more gas may be exhausted from confined area  204 , thereby decreasing the pressure level (P w ) within confined chamber region  204 . 
         [0035]    Since two paths ( 214  and  212 ) are shown in  FIG. 2  for exhausting gas from confined chamber region  204 , the overall conductance rate for confined chamber region  204  may be a factor of both the lower path conductance rate and the upper path conductance rate. Similar to lower path  214 , when confinement ring  202  is adjusted, the upper path conductance rate may also change. In an embodiment, the counter effect may vary depending upon the length of the path (L). In an example, by moving confinement ring  202  downward, the portion of upper path  212  between unitized confinement ring  202  and upper electrode  206  is shortened (i.e., the length of the upper path  212 ), thereby increasing the rate of exhaust. In another example, the rate of exhaust may decrease as the portion of upper path  212  between unitized confinement ring  202  and upper electrode  206  is lengthened when confinement ring  202  is moved vertically upward since a longer path usually creates more resistance to the gas flow. 
         [0036]    In another embodiment, the distance (gap  228 ) between the side wall of confinement ring  202  and the right side wall of upper electrode  206  may have an impact on the overall conductance rate. In other words, the width of gap  228  may change the conductance rate of upper path  212 . In an example, a wider gap  228  may increase the conductance rate of upper path  212 . For example, a processing chamber A with a narrow gap  228  may have less impact on the overall conductance rate than a processing chamber B with a wider gap  228 . 
         [0037]    In an embodiment, a set of plungers  222  may be attached to confinement ring  202  at available attachment points. The number of plungers may depend upon the number of attachment points. The plungers may be moved concurrently to adjust confinement ring  202  vertically up/down. In an embodiment, set of plungers  222  may be coupled to a precision vertical movement arrangement  224  (such as a stepper assembly, a CAM ring arrangement, etc.). Precision vertical movement arrangement  224  may be employed to move confinement ring  202  into a position that enables the pressure level (P w ) within confined chamber region  204  to be maintained at the desired recipe step level. 
         [0038]    In an embodiment, set of plungers  222  may be moved in response to processing data (such as pressure data) collected by a set of sensors (such as sensor  226 ). The pressure data may be sent to precision vertical movement arrangement  224 , which may also include a module for processing and analyzing the pressure data. If the processing data traverses a threshold range, set of plungers  222  may be moved vertically up/down in order to change the pressure level within confined chamber region  204 . In an example, if the processing data indicates that the pressure level is above the pre-defined threshold, gap  218  may be increased to reduce the pressure within confined chamber region  204 . In an embodiment, at least one of the collection of data, the analysis of data and the adjustment of set of plungers  222  may be performed automatically without human intervention. 
         [0039]    As discussed herein, the term traverse may include exceed, fall bellow, be within range, and the like. The meaning of the word traverse may depend upon the requirement of the threshold value/range. In an example, if the recipe requires the pressure value, for example, to be at least a certain value, then the processing data is considered to have traversed the threshold value/range if the pressure value is below the threshold value/range. In another example, if the recipe requires the pressure value, for example, to be below a value, then the processing data has traversed the threshold value/range if the pressure value is above the threshold value/range. 
         [0040]    In an embodiment, confinement ring  202  may include one or more slots  250 . The set of slots (n) may be employed to provide for additional paths for exhausting gas from the confined chamber region, in an embodiment. The slots may be equal in length or may have different lengths. The slots may be equally or unequally spaced. The length and cross-sectional area of the slots may also vary. In one embodiment, the set of slots may include a path to facilitate detection of plasma condition by an optical sensor, which may be employed to capture end point data during substrate processing. 
         [0041]    In an embodiment, confinement ring  202  may be employed to manage plasma confinement while an external component may be employed to perform pressure control. Those skilled in the art are aware that some recipes may require the components within a processing chamber to be stationary during processing. In this type of environment, confinement ring  202  may be positioned at a predetermined stationary position. The predetermined stationary position may be at a position that minimizes the possibility of plasma unconfinement. In an embodiment a valve such as a vat valve  252  may be employed to adjust the pressure level within confined chamber region  204 . 
         [0042]      FIG. 3A  shows, in an embodiment of the invention, a cross-sectional view of a unitized confinement ring with a high inductance upper path implementation. In an embodiment the plasma processing system may be a capacitively-coupled plasma (CCP) processing system. Processing chamber  300  may include a confinement ring  302  configured to surround the periphery of the chamber volume where plasma is formed (i.e., confined chamber region  304 ). Confinement ring  302  is similar to confinement ring  202  except that the upper part of confinement ring  302  has a shoulder feature  330 . 
         [0043]    Similar to  FIG. 2 , an upper electrode  306  and a bottom ground extension  310  may also defined part of the periphery of confined chamber region  304 . In an embodiment, upper electrode  306  may include a protrusion (a shelf feature  332 ). Thus, when confinement ring  302  is moving vertically downward, the distance that confinement ring  302  may travel may not only be defined by the top surface of bottom ground extension  310  (similar to  FIG. 2 ) but also by shelf feature  332 . 
         [0044]    During substrate processing, two paths ( 312  and  314 ) may be available for evacuating the exhaust gas from a confined chamber region  304 . The conductance rate may be controlled by adjusting a gap  318  (D) between the bottom surface of confinement ring  302  and the top surface of bottom ground extension  310 . In an example, to reduce the conductance rate, a set of plungers  322  may be lowered to cause confinement ring  302  to travel vertically downward thereby narrowing gap  318 . At the same time, a gap  328  is also narrowed as shoulder feature  330  get closer in proximity to shelf feature  332  of upper electrode  306 . 
         [0045]    In an embodiment, gap  318  and gap  328  may have the same width. Thus, when shoulder feature  330  is resting on shelf feature  332 , gas is not being exhausted from confined chamber region  304  since both paths  312  and  314  have been choked off. 
         [0046]    In another embodiment, gaps  318  and  328  may have different width measurements. In an example, gap  318  may be larger than gap  328 . In this example, only path  312  is choked off when shoulder feature  330  rests on shelf feature  332  while path  314  is still available for evacuating the exhaust gas. In another example, gap  318  is smaller than gap  328 . As a result, only path  314  is choked off when the bottom surface of confinement ring  302  rests on the top surface of bottom ground extension  310 . In other words, path  312  is still available for evacuating the exhaust gas. 
         [0047]    In an embodiment, instead of a shelf-shoulder arrangement, an upper left side wall ( 364 ) of confinement ring  302  may be sloped (as shown in  FIG. 3B ,  FIG. 3C , and  FIG. 3D ). In an example, upper left side wall  364  of confinement ring  302  may be at an angle less than 90 degrees. Similarly, a portion of the right side wall ( 362 ) of upper electrode  306  may be sloped. In an example, a portion of right side wall  362 ) of upper electrode may be at an angle greater than 90 degrees. Thus, a gap  360  may be formed between the two side walls to enable the exhaust gas to be evacuated. The conductance rate may be controlled by adjusting gap  360 . In an example, to reduce the conductance rate, confinement ring  302  may be moved vertically downward to reduce gap  360 , thereby increasing the pressure within confined chamber region  304  ( FIG. 3C ). Conversely, to increase the conductance rate, confinement ring  302  may be moved vertically upward to increase gap  360 , thereby decreasing the pressure within confined chamber region  304  ( FIG. 3D ). 
         [0048]    In an embodiment, a sensor  326  may be employed to collect pressure data within confined chamber region  304 . The pressure data may be sent to a precision vertical movement arrangement  324  (such as a stepper assembly, a CAM ring arrangement, etc.) for analysis. If the pressure level has traversed a predefined threshold range, the set of plungers  322  may be moved to adjust confinement ring  302  to a new position. Similar to  FIG. 2 , in an embodiment, at least one of the collection of data, the analysis of data, and the adjustment of set of plungers  322  may be performed automatically without human intervention. 
         [0049]    In an embodiment, confinement ring  302  may include one or more slots  350 . The set of slots (n) may provide additional paths for exhausting gas from the confined chamber region, in an embodiment. The slots may be equal in length or may have different lengths. The slots may be equally or unequally spaced. The length and cross-sectional area of the slots may also vary. In one embodiment, the set of slots may include a path to facilitate detection of plasma condition by an optical sensor, which may be employed to capture end point data during substrate processing. 
         [0050]    In an embodiment, confinement ring  302  may be employed to manage plasma confinement while an external component may be employed to perform pressure control. Consider the situation wherein, for example, a recipe requires all components within a processing chamber to be stationary during the execution of the recipe. In this type of environment, confinement ring  302  may be positioned at a predetermined stationary position. The predetermined stationary position may be at a position that minimizes the possibility of plasma unconfinement. In an embodiment a valve such as a vat valve  352  may be employed to adjust the pressure level within confined chamber region  304 . 
         [0051]    As aforementioned, conductance rate is affected by not only the cross-sectional dimension of the path but also by the length and spacing of the path.  FIG. 4  and  FIG. 5  are examples of how a unitized confinement ring arrangement may be employed to change the length of the path to perform plasma confinement and pressure control. 
         [0052]      FIG. 4  shows, in an embodiment of the invention, a cross-sectional view of a unitized confinement ring arrangement within a processing chamber  400  of a plasma processing system. In an embodiment, the plasma processing system is a capacitively-coupled plasma (CCP) processing system. Consider the situation wherein, for example, a substrate is being processed within processing chamber  400 . During substrate processing, plasma is formed above the substrate to perform etching. 
         [0053]    A confinement ring  402  is employed to surround the plasma generating region (i.e., confined chamber region  404 ), in an embodiment, in order to confine the plasma. Similar to  FIG. 2 , confinement ring  402  is a single unitized confinement ring. However, confinement ring  402  may extend from an upper electrode  406  downward past the top surface of a bottom ground extension  410 . 
         [0054]    Unlike  FIG. 2 , both gap  458  (distance between left side wall of confinement ring  402  and right side wall of upper electrode  406  in  FIG. 4 ) and gap  418  (distance between left side wall of confinement ring  402  and right side wall of bottom ground extension  410  in  FIG. 4 ) may be at a fixed distance. To control the conductance rate of gas exhaust, the length of each of the paths ( 412  and  414 ) may be adjusted. 
         [0055]    In an embodiment, the exhausted gas may be evacuated from confined chamber region  404  by moving confinement  402  vertically (up/down). As can be seen from Equation 1 above, as the length of the path (L) increases, the rate of conductance decreases. In other words, as the path lengthens, the resistance in the gas flow is increased. As a result, less gas may be exhausted from the plasma generating region and the pressure within confined chamber region  404  may increase. 
         [0056]    As can be appreciated from the foregoing, paths  412  and  414  may have countering affect on one another. In an example, as confinement ring  402  is moved vertically downward, the portion of path  414  lengthens between unitized confinement ring  402  and bottom ground extension  410  while the portion of path  412  between unitized confinement ring  402  and upper electrode  406  has shortened. As a result, the conductance rate for lower path  414  increases while the conductance rate for upper path  412  decreases. Thus, in determining the overall conductance rate for confined chamber region  404 , the conductance rates through both paths may be considered. 
         [0057]    In an embodiment, the configuration of confinement ring  402  may minimize the possibility of variability in the conductance rate in the upper path ( 412 ). In an example, the configuration of confinement ring  402  may be such that as confinement ring  402  is moved downward, the length between the left side of confinement ring  402  and the right side of upper electrode  406  remains the same, thereby keeping the conductance rate in the upper path ( 412 ) to be relatively unchanged. In this type of configuration, the overall rate of conductance may be controlled by adjusting lower path  414 . 
         [0058]    In an embodiment, confinement ring  402  may be attached to a set of plungers  422  at the available attachment points. Again, the number of plungers depends upon the number of attachment points. The set of plungers may be moved concurrently to adjust the vertical portion of confinement ring  402 . Similar to  FIG. 2 , a precision vertical movement arrangement  424  (such as a stepper assembly, a CAM ring arrangement, etc.) may be employed to control the movement of set of plungers  422 . 
         [0059]    In an embodiment, a feedback arrangement may be provided. The feedback arrangement may include a sensor  426  that may be employed to collect data about the pressure level within confined chamber region  404 . The pressure data may be sent to precision vertical movement arrangement  424  for analysis. If the processing data traverses a threshold range, set of plungers  422  may be moved vertically in order to change the pressure level within confined chamber region  404 . In an embodiment, at least one of the collection of data, the analysis of data and the adjustment of set of plungers  422  may be performed automatically without human intervention. 
         [0060]    In an embodiment, confinement ring  402  may be employed to manage plasma confinement while an external component may be employed to perform pressure control. Consider the situation wherein, for example, a recipe requires all components within a processing chamber to be stationary during the execution of the recipe. In this type of environment, confinement ring  402  may be positioned at a predetermined stationary position. The predetermined stationary position may be at a position that minimizes the possibility of plasma unconfinement. In an embodiment a valve such as a vat valve  452  may be employed to adjust the pressure level within confined chamber region  404 . 
         [0061]    In an embodiment, confinement ring  402  may additionally or alternatively be implemented with a set of slots, as shown in  FIG. 5 . As aforementioned, besides size and length of the paths for exhausting gas from a confined chamber region, the number of paths (n) and spacing available for exhausting may also be a factor in the conductance rate. In an example, confinement ring  402  may have four slots ( 502 ,  504 ,  506 , and  508 ). Thus, instead of only two paths ( 412  and  414 ) being available for exhausting gas from confined chamber region  404 , additional four paths are available for evacuating the exhaust gas. 
         [0062]    In an embodiment, the conductance rate of gas exhaust may also be controlled by adjusting the number of slots available. In an example, to reduce the conductance rate, one or more of the slots may be blocked to prevent the gas from exiting confined chamber region  404  through the paths provided by the slots. In an example, slots  502  and  504  are positioned below the top surface of bottom ground extension  410 . Thus, only slots  506  and  508  are available to exhaust the gas from confined chamber region  404 . In other words, as confinement ring  402  is moved vertically down, slots  502  and  504  may be blocked by bottom ground extension  410 . As a result, the paths through slots  502  and  504  may no longer be available for evacuating the exhaust gas from confined chamber region  404 . 
         [0063]      FIGS. 2-5  have been discussed in relation to Equation 1. However, those skilled in the art are aware that Equation 1 is but one example of an equation for calculating the rate of conductance. Equation 1 has been utilized as an example to show the relationship between three variables (D, L, and n) that may affect the rate of conductance. Other equations may be also employed to calculate the rate of conductance. In an example, Equation 2 below shows an example of another equation that may be employed to calculate the rate of conductance. 
         [0000]    
       
         
           
             
               
                 
                   
                     C 
                     = 
                     
                       
                         2 
                         * 
                         K 
                         * 
                         
                           w 
                           2 
                         
                         * 
                         
                           h 
                           2 
                         
                         * 
                         
                           v 
                           _ 
                         
                       
                       
                         3 
                          
                         
                           ( 
                           
                             w 
                             + 
                             h 
                           
                           ) 
                         
                         * 
                         t 
                       
                     
                   
                   , 
                   
                     
                       v 
                       _ 
                     
                     = 
                     
                       
                         
                           8 
                            
                           kT 
                         
                         
                           π 
                            
                           
                               
                           
                            
                           m 
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                      
                     
                         
                     
                      
                     2 
                   
                   ] 
                 
               
             
           
         
       
     
         [0064]    Again, C=rate of conductance; K=constant; w=width; h=height; v=velocity; t=thickness; T=temperature; and m=mass of gas 
         [0065]    As can be appreciated from the forgoing, one or more embodiments of the present invention provide for a unitized confinement ring arrangement. With a unitized confinement ring, the conductance rate may be managed by varying the number of paths, the size of the paths, and/or the length of the paths available, and the like. By simplifying the design, fewer mechanical components are required to perform the function of plasma confinement and/or pressure control within the plasma generating region. Since there are fewer mechanical components, the unitized confinement ring arrangement is more reliable and the cost of maintaining and servicing the unitized confinement ring arrangement is less expensive. 
         [0066]    While this invention has been described in terms of several preferred embodiments, there are alterations, permutations, and equivalents, which fall within the scope of this invention. Although various examples are provided herein, it is intended that these examples be illustrative and not limiting with respect to the invention. 
         [0067]    Also, the title and summary are provided herein for convenience and should not be used to construe the scope of the claims herein. Further, the abstract is written in a highly abbreviated form and is provided herein for convenience and thus should not be employed to construe or limit the overall invention, which is expressed in the claims. If the term “set” is employed herein, such term is intended to have its commonly understood mathematical meaning to cover zero, one, or more than one member. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.