Abstract:
A plasma process chamber includes a top electrode, a bottom electrode disposed opposite the top electrode, the bottom electrode capable of supporting a substrate. The plasma process chamber also includes a plasma containment structure defining a plasma containment region, the plasma containment region being less than an entire surface of the substrate. The plasma containment structure rotates relative to the substrate and wherein the plasma containment region includes a center point of the substrate throughout the rotation of the plasma containment structure relative to the substrate. The plasma containment structure includes multiple gaps. A vacuum source is coupled to the gaps in the plasma containment structure. A method of processing a substrate is also described.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application No. 61/560,292 filed on Nov. 15, 2011 and entitled “System, Method and Apparatus of a Wedge-Shaped Parallel Plate Plasma Reactor for Substrate,” which is incorporated herein by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     The present invention relates generally to plasma reaction chambers, and more particularly, to methods, systems and apparatus for plasma reaction chambers having processing areas less than the total area of the surface being processed. 
       FIG. 1A  is a side view of a typical parallel-plate, capacitive, plasma processing chamber  100 .  FIG. 1B  is a top view of a substrate  102  processed in the typical parallel-plate, capacitive, plasma processing chamber  100 . The typical plasma processes processing chamber  100  includes a top electrode  104 , a bottom electrode  106  supporting a substrate to be processed  102 . The top electrode  104  is typically a showerhead type electrode with multiple and inlet ports  109 . The multiple inlet ports  109  allow process gases  110  in across the width of the processing chamber  100 . 
     The typical parallel-plate, capacitive plasma reactor  100  is used for processing round planar substrates. Common processes are dielectric etch and other etch processes. Such plasma reactors typically suffer from inherent center-to-edge non-uniformities of neutral species. 
     The center-to-edge non-uniformities of neutral species arises from the differences in one or more of a flow velocity, an effective gas residence time, and gas chemical composition present at the center of the substrate as compared to the flow velocity, effective gas residence time, and gas chemical composition present at the edge. The gas chemical compositions can be influenced by composition and flow of injected gas mixtures; gas-phase dissociation, exchange and recombination reactions; as well as recombination products and byproducts from surface mediated etch. 
     By way of example, as the process gases are introduced across the width of the processing chamber the plasma  112  is formed between the top electrode  104  and bottom electrode  106 . Plasma byproducts  118  are formed by reactions of plasma radicals and neutrals in the gas phase and/or with the surface of the substrate  102 . The plasma byproducts  118  are transported to the sides of the substrate where they may exit the plasma and eventually are removed from the chamber by pumps  108 . Plasma byproducts can include products from one or more dissociation reactions (e.g., CF4+e − →CF3+F+e − ) and/or one or more ionizations (e.g., CF4+e − →CF3 + +F) and/or one or more excitations (e.g., Ar+e − →Ar*+e − ) and/or one or more attachments (e.g., CF4+e − →CF3+F − ) and/or one or more binary reactions (e.g., CF3+H→CF2+HF). 
     Plasma byproducts  118  can also include substrate etch byproducts including SiF2, SiF4, CO, CO2, and CN. Etch byproducts can also dissociate and react in the plasma  112  to form other species. 
     Recombination also occurs during the plasma processing. Recombination is a chemical reaction in which two neutral species combine to form a single molecule, the recombination product  120 . Recombination typically occurs when the radicals and neutrals from the plasma  112  interact at surfaces such as the bottom surface of the top electrode  104 . The recombination products  120  may be transported off the side of the substrate  102  into pumps  108 , similar to the plasma byproducts  118 . Plasma recombination products  120  can arise from one or more wall or surface binary reactions (e.g., F+CF→CF2, and/or H+H→H2, and/or O+O→O2, and/or N+N→N2). Plasma-surface interactions can also include deposition of films pm the wall or other internal surface of the chamber  100  e.g. CFx radicals may deposit a polymer film. 
     It should be noted that as shown in  FIG. 1A , the plasma byproducts are lost from one side of the substrate  102  and the recombination products  120  are lost from the opposite side of the substrate  102  for clarity purposes only. In actual practice, those skilled in the art would realize that both the recombination products  120  and the plasma byproducts  118  are intermixed and lost from both sides of the substrate  102  to pumps  108 . 
     During plasma processing the concentrations of the chemical species vary from the center to the edge of the substrate  102 . These species include recombination products  120 , the plasma byproducts  118 , as well as unmodified injected gases. Due to these nonuniformities in chemical speciation, as well as other possible non-uniform conditions such as substrate surface temperature, ion flux, ion energy, etc., the effective plasma processing of the substrate, e.g. etching of a target film in a structure, varies from the center to the edge of the substrate  102 . 
     By way of example, the plasma radical species could be most concentrated at the center of the substrate  102  in plasma processing regions  114 A and  116 A over central portion  102 A of the substrate  102 . Further, the radicals could be somewhat less concentrated in intermediate plasma processing regions one  114 B and  116 B over intermediate portion  102 B of the substrate  102 . Further still, the concentrations of the radicals could be even less concentrated in edge plasma processing regions  114 C and  116 C over the edge portion  102 C of the substrate  102 . 
     Thus, in this example, if the local radical density controls the plasma-induced etch rate, the highest etch rate would occur in the center plasma processing regions  114 A and  116 A over the center portion  102 A of substrate  102  as compared to a slightly lower etch rate in the intermediate plasma processing regions  114 B and  116 B over the intermediate portion  102 B of substrate  102  and even lower etch rate in the plasma processing of the edge plasma processing regions  114 C and  116 C over the edge portion  102 C of the substrate. This would result in a center-to-edge nonuniformity of the substrate  102  film thickness after processing. Radial variations in etch and deposition rates are typical problems for commercial plasma processing systems, as applied to round flat substrates such as wafers. 
     This center-to-edge nonuniformity is exacerbated in small volume product plasma processing chambers that have a very large aspect ratio. For example, a very large aspect ratio is defined as when the width W of the substrate is about four or more or more times the height H of the plasma processing region. The very large aspect ratio of the plasma processing region limits the effectiveness of gas-phase diffusion for mixing neutral species, and thus tends to worsen the non-uniformity of the plasma byproducts  118  and recombination products  120  in the plasma processing regions  114 A- 116 C. 
     Although this center-to-edge non-uniformity of neutral species is not the only cause of center-to-edge process non-uniformity, in many dielectric etch applications it is a significant contributor. Specifically, neutral-sensitive processes such as gate or bitline mask open, photoresist (PR) strip over low-k films, highly selective contact/cell, and dual-damascene (DD) via etch may be especially sensitive to these effects. Similar problems may apply in other parallel-plate plasma reactors, besides those used for wafer dielectric etch. 
     In view of the foregoing, there is a need for improving the center-to-edge chemical species uniformity in plasma etch processes. 
     SUMMARY 
     Broadly speaking, the present invention fills these needs by providing an improved parallel plate plasma processing chamber. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, computer readable media, or a device. Several inventive embodiments of the present invention are described below. 
     One embodiment provides a plasma process chamber including a top electrode, a bottom electrode disposed opposite the top electrode, and a bottom electrode capable of supporting a substrate. The plasma process chamber also includes a plasma containment structure defining a plasma containment region over the substrate, with the area defined by plasma containment region being less than an entire surface of the substrate. The plasma containment structure rotates relative to the substrate and wherein the plasma containment region includes a center point of the substrate throughout the rotation of the plasma containment structure relative to the substrate. The plasma containment structure includes multiple gaps. A pumped vacuum region is coupled to the gaps in the plasma containment structure. 
     The plasma containment structure can include a containment ring and an inner containment. The top electrode can be coupled to a top electrode bias potential and the bottom electrode can be coupled to bottom electrode bias potential. The gaps in the plasma containment structure determine a greater first pressure of one or more process gas in the plasma containment region and a lesser second pressure of a remaining portion of the process chamber outside the plasma containment region. The first pressure can be at least twice the second pressure. 
     The top electrode can be coupled to at least one process gas source and the top electrode includes multiple inlet ports. A first portion of the inlet ports are open and a second portion of the inlet ports are closed, the first portion being disposed within the plasma containment region and the second portion being disposed within a remaining portion of the process chamber outside the plasma containment region. 
     The containment structure can include a containment angle of between about 30 degrees and about 330 degrees. A first portion of the gaps in the plasma containment structure are formed between the plasma containment structure and the lower electrode. A second portion of the gaps in the plasma containment structure are formed in the plasma containment structure. 
     The plasma containment structure can include an inner containment extension, the inner containment extension extending from the plasma containment structure between the top electrode and the bottom electrode into a remaining portion of the process chamber outside the plasma containment region. The plasma process chamber can be included in an integrated system including an integrated system controller coupled to the plasma process chamber, the integrated system controller including a user interface, logic for monitoring and controlling the plasma process chamber and logic for collecting, storing, displaying, and analyzing data from the plasma process chamber. 
     Another embodiment provides a plasma process chamber including a top electrode, a bottom electrode disposed opposite the top electrode, the bottom electrode capable of supporting a substrate. The plasma process chamber also including a plasma containment structure defining a plasma containment region, the plasma containment region being less than an entire surface of the substrate, wherein the plasma containment structure rotates relative to the substrate an wherein the plasma containment region includes a center point of the substrate throughout the rotation of the plasma containment structure relative to the substrate, wherein plasma containment structure include a containment ring and an inner containment, wherein the containment structure includes a containment angle of between about 30 degrees and about 330 degrees. The plasma process chamber also includes multiple gaps in the plasma containment structure, wherein the gaps in the plasma containment structure determine a greater first pressure of one or more process gas in the plasma containment region and a lesser second pressure of a remaining portion of the process chamber outside the plasma containment region. A vacuum source can be coupled to the gaps in the plasma containment structure. 
     Yet another embodiment provides a method of processing a substrate including loading a substrate in a processing chamber, wherein the substrate is supported on a bottom electrode and wherein the processing chamber includes a top electrode opposing the bottom electrode. The method of processing the substrate also including placing a plasma containment structure over a selected portion of the surface of the substrate to define a plasma containment region of the selected portion of the surface of the substrate and injecting at least one process gas into the plasma containment region. The top electrode and the bottom electrode as biased. Process byproducts are exhausted from the plasma containment region. The plasma containment region is moved relative to the substrate to selectively eventually pass over the entire surface of the substrate. 
     A first pressure of the least one process gas in the plasma containment region is at least twice a second pressure of a remaining portion of the process chamber outside the plasma containment region. The plasma containment structure can include an inner containment extension, the inner containment extension extending from the plasma containment structure between the top electrode and the bottom electrode into a remaining portion of the process chamber outside the plasma containment region. 
     The containment structure can include a containment angle of between about 30 degrees and about 330 degrees. The top electrode can be coupled to at least one process gas source and the top electrode can include multiple inlet ports, wherein a first portion of the inlet ports are open and a second portion of the inlet ports are closed, the first portion being disposed within the plasma containment region and the second portion being disposed within a remaining portion of the process chamber outside the plasma containment region. 
     At least one of the top electrode bias potential and the bottom electrode bias potential can be applied to the respective top electrode and bottom electrode. 
     Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. 
         FIG. 1A  is a side view of a typical parallel-plate, capacitive, plasma processing chamber. 
         FIG. 1B  is a top view of a substrate processed in the typical parallel-plate, capacitive, plasma processing chamber. 
         FIG. 2A  is a side sectional view of a plasma processing chamber, in accordance with an embodiment of the present invention. 
         FIG. 2B  is a top view of a plasma processing chamber with the top electrode not shown, in accordance with an embodiment of the present invention. 
         FIG. 2C  is a top view of a plasma processing chamber with the top electrode not shown, in accordance with an embodiment of the present invention. 
         FIG. 2D  is a perspective view of a plasma processing chamber, in accordance with an embodiment of the present invention. 
         FIG. 2E  is a top view of a plasma processing chamber with the top electrode not shown, in accordance with an embodiment of the present invention. 
         FIG. 2F  is a top view of a plasma processing chamber with the top electrode not shown, in accordance with an embodiment of the present invention. 
         FIG. 2G  is electrical schematic of a processing chamber, in accordance with an embodiment of the present invention. 
         FIG. 3A  is a side sectional view of a plasma processing chamber, in accordance with an embodiment of the present invention. 
         FIG. 3B  is a top view of a plasma processing chamber, with the top electrode not shown, in accordance with an embodiment of the present invention. 
         FIG. 3C  is a perspective view of the plasma processing chamber, in accordance with an embodiment of the present invention. 
         FIG. 4  is a side sectional view of a plasma processing chamber, in accordance with an embodiment of the present invention. 
         FIG. 5  is a flowchart of the method operations of a plasma processing chamber, in accordance with an embodiment of the present invention. 
         FIG. 6  is a block diagram of an integrated system including one or more of the plasma processing chambers, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Several exemplary embodiments for an improved parallel plate plasma processing chamber will now be described. It will be apparent to those skilled in the art that the present invention may be practiced without some or all of the specific details set forth herein. 
     The invention reduces center-to-edge differences in the neutral species densities by separating the circular symmetry traditionally used in parallel-plate wafer etching. In one wedge-shaped region of the reactor, the wafer is processed by a plasma, for example a capacitive discharge plasma. This wedge is called the plasma containment region. In the complementary wedge or portion of the processing chamber outside the containment region, there is little or no plasma present, such that the extent of substrate processing in this “non-etch” region is minimal compared to the containment region. The portion of the processing chamber outside the plasma containment region provides an efficient gas conductance path for effluent. Because this region is arranged to always be close to the center region of the substrate, the effective pumping of gases from the center is increased relative to the traditional circular-plasma arrangement. The center region of the substrate, within the plasma containment region but near the tip of containment region, is pumped nearly as efficiently as the region near the edge of the substrate within the plasma confinement region. This enhanced center region gas removal substantially balances the inherent non-uniformity of the center pumping in the conventional parallel-plate geometry for round planar substrates. The substrate and/or the wedge-based upper hardware would be rotated to ensure all areas of the substrate are exposed to plasma for substantially equal times in the course of one cycle, thus providing azimuthally uniform process results, when averaged over multiple rotations. 
     The etch region can have a plasma containment region (i.e., wedge) encompassing more than about 270 degrees of a circle. This ensures reasonably high processing rates compared to prior art. The complementary non-etch region in the portion of the processing chamber outside the plasma containment region would include plasma confinement along both radial boundaries, to exclude plasma from the non-etch region. 
     Gas transport from the plasma containment region to the non-etch region is provided around and through the confinement structure. The plasma confinement structure allows significant gas conductance while excluding the plasma as will be described in more detail below. Gas removal near the center of the substrate (e.g., a tip of the non-etch wedge), relative to the edge, can be enhanced by including a pump-out port in the upper surface near the tip of the non-etch wedge, leading to a vacuum pump. 
     Radial and azimuthal variations in the gap between substrate and top surface can be used to tune the gas conductance versus radius, to deliver an optimal neutral uniformity in the containment region. The containment structure can also provide a pressure differential between the pressure inside the containment structure and a pressure external to the containment region. This pressure differential helps to maintain a no-plasma condition in the non-etch region while a plasma sustaining condition exists in the containment region. 
     RF bias power can be applied to the substrate and the top electrode can be grounded in the containment region. The local conditions of the containment region, including gap, pressure, surface temperatures, and plasma density would be targeted to be similar to typical prior art parallel-plate plasma reactors. 
     A more uniform neutral speciation center-to-edge is produced as compared to conventional parallel-plate wafer processing or any known variations. Traditionally one method for improving center-to-edge neutral uniformity is to increase the reactor gap. But this doesn&#39;t eliminate the problem, it just smoothes the variations out by diffusion, with the usually negative tradeoffs of lower plasma density, longer gas residence time, and variations in plasma uniformity. 
     Although other configurations may be imagined where the substrate moves relative to the upper electrode of the process chamber, in the present invention every point on the substrate is exposed to plasma for a substantially equal amount of time. This is inherent in the wedge shape and the rotation of the substrate and/or the containment structure. 
     The present invention is superior to line-shaped plasma sources, with linear motion perpendicular to the line, because it avoids possible plasma loading non-uniformities as the width of the processed region varies while the substrate scans across the plasma line. The present invention is superior to typical parallel-plate substrate processing schemes that would add pumping ports in the top plate, because that approach leads to the inherent plasma and neutral non-uniformities near the pump ports, and requires the confinement of plasma close to the pump ports. The present approach avoids these problems, such that the plasma containment region of the process chamber has a substantially uniform plasma and neutral environment, free from local hardware effects in the top end. Also the present invention separates the plasma confinement from optional pump-out ports in the top hardware, simplifying the engineering of both functions. 
       FIG. 2A  is a side sectional view of a plasma processing chamber  200 , in accordance with an embodiment of the present invention. The plasma processing chamber  200  includes containment structure. The containment structure includes an edge containment ring  202  and an inner containment  204 . The edge containment ring  202  and inner containment  204  constrain the plasma  201  over a selected portion  102 E of the surface of the substrate  102 . The edge containment ring  202  and inner containment  204  can be formed from any suitable dielectric materials and combinations thereof (e.g., ceramic, silicon dioxide, quartz, etc.) 
     The containment ring  202  is substantially close to the edge of the substrate  102  and leaves only a relatively small gap  203  between the edge of the substrate and the containment ring. The gap  203  is between about 0.2 mm and about 4 mm. Thus the plasma byproducts  118  and recombination byproducts  120  can escape the plasma processing region via the relatively small gap  203  to the pumps  108 . 
     The plasma  201  is constrained between the inner containment  204  and the edge containment ring  202 . The inner containment  204  prevents the plasma  201  from being formed over the remaining surface area  102 F of the substrate  102 . The inner containment  204  provides at least one gap  205 A,  205 B, between the inner containment and the top electrode  104  and between the inner containment and the surface of the substrate  102 . The gap(s)  205 A,  205 B are between about 0.3 mm and about 6 mm. Thus the plasma byproducts  118  and recombination byproducts  120  can escape the plasma processing region via the relatively small gaps  205 A,  205 B and then through a high-conductance path  216  to the pumps  108 . 
     The containment ring  202  is and the inner containment  204  also concentrate the process gases  110  and thus determine the location where the plasma  201  can be supported. A minimum concentration and/or pressure of process gases  110  are needed before a plasma  201  can be supported between the top electrode  104  and the bottom electrode  106 . The pressure in the plasma containment region  214  is approximately at least twice the pressure as remaining portion  216  of the process chamber  200  outside the containment region. 
     A combination of the flow rate of the process gases into the plasma containment region  214  and the relatively small gaps  203 ,  205 A,  205 B maintains the pressure differential between the plasma containment region and the remainder of the process chamber  200 . As a result of the pressure differential, the plasma  201  can only be supported within the plasma containment region  214 . Therefore, there will be no plasma present in the portion  216  of the process chamber  200  outside the plasma containment region  214  because the process gases  110  are not concentrated sufficiently to support a plasma outside the containment region. 
     The plasma  201  can also be constrained to the plasma containment region  214  because the process gases  110 ′ are substantially stopped from flowing into the portion  216  of the process chamber  200  outside the plasma containment region  214 . Thus there is an insufficient concentration of the process gases in the portion  216  of the process chamber  200  outside the plasma containment region  214 . The top electrode can include a one or more valves and/or manifold system (not shown) to control or stop the flow of process gases  110 ′ the portion  216  of the process chamber  200  outside the plasma containment region  214 . 
     The plasma  201  can also be constrained to the plasma containment region  214  because one or both of the top electrode  104  and bottom electrode  106  can be selectively biased. By way of example only that portion of the top electrode  104  included within the plasma containment region  214  might be biased and the remaining portion of the top electrode  104  that is not included within the plasma containment region remains unbiased or biased in a different manner to prevent formation of plasma outside the containment region. Similarly, the only that portion of the bottom electrode  106  included within the plasma containment region  214  might be biased and the remaining portion of the bottom electrode  106  that is not included within the plasma containment region remains unbiased or biased in a different manner to prevent formation of plasma outside the containment region. 
       FIG. 2B  is a top view of a plasma processing chamber  200  with the top electrode  104  not shown, in accordance with an embodiment of the present invention. As shown in  FIG. 2B , the plasma processing chamber  200  has a containment ring  202  and inner containment  204  containing a plasma processing region over a containment angle  212  of about 180 degrees. The containment angle  212  of about 180 degrees selects a portion  102 E of slightly more than one half of the substrate  102  surface. 
     The plasma containment ring  202  and inner containment  204  can move relative to the surface of the substrate  102 . By way of example, the plasma containment in ring  202  and inner containment  204  can rotate relative to the surface of the substrate  102  in one or both directions  210 A,  210 B. Alternatively, the substrate  102  can rotate relative to the plasma containment ring  202  and inner containment  204 . Alternatively, both the substrate  102  and the plasma containment in ring  202  and inner containment  204  can rotate relative to one another. 
     Moving the inner containment  204  over the surface of the substrate  102  allows plasma processing of the entire surface of the substrate  102  in the course of a complete cycle of motion. It should be noted that the center  102 D of the substrate  102  is maintained within the plasma processing region as the plasma containment ring  202  and inner containment  204  are moved relative to the surface of the substrate  102 . 
       FIG. 2C  is a top view of a plasma processing chamber  200 ′ with the top electrode  104  not shown, in accordance with an embodiment of the present invention.  FIG. 2D  is a perspective view of a plasma processing chamber  200 ′, in accordance with an embodiment of the present invention. As shown in  FIGS. 2C and 2D , the plasma processing chamber  200  has a containment ring  202  and inner containment  204  containing a plasma processing region over a containment angle  212  of about 90 degrees. 
       FIG. 2E  is a top view of a plasma processing chamber  200 ″ with the top electrode  104  not shown, in accordance with an embodiment of the present invention. Plasma processing chamber  200 ″ has a containment ring  202  and inner containment  204  containing a plasma processing region over a containment angle  212  of less than about 90 degrees, e.g., between less than about 30 degrees and about 90 degrees. 
       FIG. 2F  is a top view of a plasma processing chamber  200 ′″ with the top electrode  104  not shown, in accordance with an embodiment of the present invention. Plasma processing chamber  200 ′″ has a containment ring  202  and inner containment  204  containing a plasma processing region over an angle  212  of greater than about 180 degrees and less than 360 degrees, e.g., between about 180 and more than about 330 degrees. As shown in various embodiments, the containment angle  212  can be between less than about 30 degrees and more than about 330 degrees. 
       FIG. 2G  is electrical schematic of a processing chamber  200 , in accordance with an embodiment of the present invention. S 1  is a bias signal applied to the top electrode  104 . S 2  is a bias signal applied to the bottom electrode  106 . Capacitor C 1  represents the effective capacitance of the plasma  201 , which may behave similar to a capacitive load for typical conditions. Capacitor C 2  represents the capacitance between the top electrode  104  and the bottom electrode  106  outside the plasma  201  plasma containment region  214 . The capacitor C 1  and capacitor C 2  are separated by the inner containment  204 . The capacitance C 1  of the plasma  201  is much greater than the capacitance of capacitor C 2 , because capacitance C 2  is mainly determined by the chamber gap which capacitance C 1  is mainly determined by the top and bottom plasma sheaths, in series, both with much small widths than the chamber gap. As a result, the impedance of capacitor C 1  is less than the impedance of capacitor C 2 . Therefore, the bulk of the current flow between the top electrode  104  and the bottom electrode  106  is through the plasma  201  in the plasma containment region  214 . This ensures efficient use of supplied current. 
       FIG. 3A  is a side sectional view of a plasma processing chamber  300 , in accordance with an embodiment of the present invention.  FIG. 3B  is a top view of a plasma processing chamber  300 , with the top electrode  104  not shown, in accordance with an embodiment of the present invention.  FIG. 3C  is a perspective view of the plasma processing chamber  300 , in accordance with an embodiment of the present invention. The plasma processing chamber  300  includes an edge containment ring  202  and an inner containment  204 . The edge containment ring  202  and inner containment  204  constrain the plasma  201  over a selected portion  102 E of the surface of the substrate  102 . The inner containment  204  also includes an inner containment extension  302 . 
     The inner containment extension  302  substantially extends over the remaining portion of the substrate  102  external from the plasma containment region  214 . The inner containment extension  302  further prevents the formation of a plasma over the remainder of the substrate  102 . The inner containment extension  302  can have an enhanced-conductance shape such as rounded end  302 A as shown or other tapered, curved, grooved, and/or tailored shapes as may be applied to improve the flow of gases  118 ,  120  from the plasma containment region  214 . The inner containment extension  302  can have a thickness  306  in whatever thickness necessary to prevent the formation of the plasma. By way of example, the inner containment extension  302  can have a thickness  306  of between 20% and about 80% of the chamber gap (height H of the plasma processing region). 
       FIG. 4  is a side sectional view of a plasma processing chamber  400 , in accordance with an embodiment of the present invention. The plasma processing chamber  400  includes an edge containment ring  402  and an inner containment  404 . As described above, with regard to the edge containment ring  202  and inner containment  204 , edge containment ring  402  and an inner containment  404  constrain the plasma  201  in the plasma containment region  214  over a selected portion  102 E of the surface of the substrate  102 . 
     The inner containment  404  can be formed in multiple layers of thinner containment elements. Gaps  405  of a desired size and number can be selectively formed between the elements of the inner containment  404  by installing the desired spacers (not shown) between the elements of the inner containment  404 . 
     Similarly, the edge containment ring  402  can be formed in multiple layers of thinner containment elements. Gaps  403  of a desired size and number can be selectively formed between the elements of the containment ring  402  by installing the desired spacers (not shown) between the elements of the edge containment ring  402 . By way of example, the gaps  403 ,  405  can be between about 0.2 mm and about 3 mm. 
     The plasma byproducts  118  and recombination products  120  can pass from the plasma containment region  214  through the gaps  403 ,  405  to the pumps  108 . The sizes and numbers of gaps  403 ,  405  can be selected to control the pressure differential between the plasma containment region  214  and the remaining portion of the processing chamber  400 . There may be between one and 6 gaps  403 ,  405  in the respective containment ring  402  and inner containment  404 . There may be a greater or lesser number of gaps in the containment ring  402  than in the inner containment  404 . The gaps  403  in the containment ring  402  may be aligned with or offset from the gaps  405  in the inner containment  404 . Each of the gaps  403 ,  405  in the respective containment ring  402  and inner containment  404  can be the same of different sizes. 
       FIG. 5  is a flowchart of the method operations of a plasma processing chamber  200 ,  200 ′,  200 ″,  200 ′″,  300 ,  400 , in accordance with an embodiment of the present invention. The operations illustrated herein are by way of example, as it should be understood that some operations may have sub-operations and in other instances, certain operations described herein may not be included in the illustrated operations. With this in mind, the method and operations  500  will now be described. 
     In operation  505  the substrate  102  is loaded in the processing chamber  200 . In an operation  510  a plasma containment ring  202 ,  402  and an inner containment  204 ,  204 A,  204 B,  404  is placed over a selected portion of the substrate  102  to define a plasma containment region  214 . The selected portion of the substrate  102  is less than the entire surface of the substrate. 
     In an operation  515 , process gases are injected into the plasma containment region  214 . In an operation  520 , the top electrode  104  and/or the bottom electrode  106  are biased to form a plasma  201  in the plasma containment region  214 . 
     In an operation  525  plasma byproducts process are exhausted around or through the plasma containment ring  202 ,  402  and the inner containment  204 ,  204 A,  204 B,  404  to the pumps  108 . 
     In an operation  530 , the plasma containment ring  202 ,  402  and the inner containment  204 ,  204 A,  204 B,  404  is rotated relative to the substrate  102  such that the plasma containment region  214  passes over the entire surface of the substrate. 
     A total process time is an integral number of rotation periods of the plasma containment region  214  relative to the surface of the substrate  102 . Where: T(total)=n×T(period). The etch time can be adjusted Maintaining T(total)&gt;&gt;T(period), and n large provides finer adjustments of etch time. T(total) can vary from one application to another. By way of example, between less than about 20 seconds and more than about 600 seconds. However, a larger T(period) can reduce mechanical issues such as excessive angular momentum or friction, etc. By way of example, T(period) can be between greater than about 0.1 second and less than about 5.0 seconds. In another example, T(period) can be between greater than about 0.2 second and less than about 2.0 seconds. 
       FIG. 6  is a block diagram of an integrated system  600  including one or more of the plasma processing chambers  200 ,  200 ′,  200 ″,  200 ′″,  300 ,  400 , in accordance with an embodiment of the present invention. The integrated system  600  includes the one or more of the plasma processing chambers  200 ,  200 ′,  200 ″,  200 ′″,  300 ,  400 , and an integrated system controller  610  coupled to the processing chamber(s). The integrated system controller  610  includes or is coupled to (e.g., via a wired or wireless network  612 ) a user interface  614 . The user interface  614  provides user readable outputs and indications and can receive user inputs and provides user access to the integrated system controller  610 . 
     The integrated system controller  610  can include a special purpose computer or a general purpose computer. The integrated system controller  610  can execute computer programs  616  to monitor, control and collect and store data  618  (e.g., performance history, analysis of performance or defects, operator logs, and history, etc.) for the plasma chamber(s). By way of example, the integrated system controller  610  can adjust the operations of the plasma chamber(s) and/or the components therein (e.g., the edge containment ring, pressures, flow rates, bias signals, loading and unloading of the substrate  102 , etc.) if data collected dictates an adjustment to the operation thereof. 
     With the above embodiments in mind, it should be understood that the invention may employ various computer-implemented operations involving data stored in computer systems. These operations are those requiring physical manipulation of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. Further, the manipulations performed are often referred to in terms, such as producing, identifying, determining, or comparing. 
     The invention can also be embodied as computer readable code on a computer readable medium and/or logic circuits. The computer readable medium is any data storage device that can store data, which can thereafter be read by a computer system. Examples of the computer readable medium include hard drives, network attached storage (NAS), read-only memory, random-access memory, CD-ROMs, CD-Rs, CD-RWs, DVDs, Flash, magnetic tapes, and other optical and non-optical data storage devices. The computer readable medium can also be distributed over a network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     Any of the operations described herein that form part of the invention are useful machine operations. The invention also relates to a device or an apparatus for performing these operations. The apparatus may be specially constructed for the required purposes, or it may be a general-purpose computer selectively activated or configured by a computer program stored in the computer. In particular, various general-purpose machines may be used with computer programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required operations. 
     It will be further appreciated that the instructions represented by the operations in the above figures are not required to be performed in the order illustrated, and that all the processing represented by the operations may not be necessary to practice the invention. Further, the processes described in any of the above figures can also be implemented in software stored in any one of or combinations of the RAM, the ROM, or the hard disk drive. 
     Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.