Patent Publication Number: US-2010116823-A1

Title: Hydroformed fluid channels

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the invention relate to a method and apparatus for forming channels on a chamber that may be used for flowing a thermal transfer fluid. 
     2. Description of the Related Art 
     Portions of chambers that are subject to extreme temperature processes often need to be regulated and maintained at a specific temperature range. In one example, a chamber used for a high temperature process may need to be cooled to a lower temperature. Generally, the chamber will include at least one wall and thermal transfer fluids are flowed within or adjacent the chamber wall to remove excess heat. Various conventional methods to form conduits for flowing the thermal transfer fluids exist. One method includes forming channels in the chamber wall by gun-drilling, which is labor intensive and expensive. Another method includes coupling a tube to the chamber wall by clamps or welds. This method is also labor intensive and has inefficient heat transfer as a great portion of the tube is not in direct contact with the chamber wall. 
     Therefore, a need exists for an improved method and apparatus for forming thermal transfer fluid channels. 
     SUMMARY OF THE INVENTION 
     Embodiments described herein provide a method and apparatus for providing a fluid channel on a surface that is subject to extreme temperatures. In one embodiment, a method for forming a fluid channel is described. The method includes providing a first member having a first thickness and a second member having a second thickness, the first thickness of the first member being at least about three times greater than the second thickness of the second member securing the first member to the second member by a continuous weld to form an initial volume circumscribed by the weld between the first member and the second member, and pressurizing the initial volume until the second member permanently deforms to expand the initial volume by at least three times. 
     In another embodiment, a method for forming a semiconductor processing chamber is described. The method includes providing a first member having a first thickness and a second member having a second thickness, the first thickness of the first member being at least about three times greater than the second thickness of the second member, securing the first member to the second member by a continuous weld, the weld defining a first volume, forming the first member and second member to define a cylinder, and pressurizing the first volume until the second member permanently deforms relative to the first member to include a second volume that is at least three times greater than the first volume. 
     In another embodiment, a sidewall for a chamber is described. The apparatus includes a first member having a first thickness, the first member comprising at least a portion of a chamber body, a second member having an second thickness, the first thickness being at least about three times greater than the second thickness, and a containment region formed between the first member and the second member by a continuous weld bead, the containment region comprising an outer surface of the first member and a portion of the second member inward of the continuous weld bead, the portion of the second member having a third thickness that is less than the second thickness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
         FIG. 1A  is an isometric view of a chamber adapted for an extreme temperature process. 
         FIG. 1B  is a cross-sectional view of one embodiment of a cooling channel disposed on the sidewall of the chamber of  FIG. 1A . 
         FIG. 2A  is an isometric view of one embodiment of a first assembly. 
         FIG. 2B  is an isometric view of a second assembly of  FIG. 2A . 
         FIG. 2C  is an isometric view of a third assembly of  FIG. 2A . 
         FIGS. 2D and 2E  are cross-sectional views of a first fluid channel profile of the second assembly shown in  FIG. 2B . 
         FIGS. 3A and 3B  are cross-sectional views of a second fluid channel profile of the third assembly shown in  FIG. 2C . 
         FIG. 4  is a schematic, cross-sectional diagram of vacuum processing chamber. 
         FIG. 5A  is an isometric view of another embodiment of a first assembly. 
         FIG. 5B  is an isometric view of a second assembly of  FIG. 5A . 
         FIG. 5C  is an isometric view of a third assembly of  FIG. 5A . 
         FIG. 6  is a cross-sectional view of a first fluid channel profile of the second assembly shown in  FIG. 5B . 
         FIG. 7  is a cross-sectional view of a second fluid channel profile of the second assembly shown in  FIG. 5C . 
         FIG. 8  is a flow chart of a method for forming a fluid channel. 
     
    
    
     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 
     Embodiments described herein generally provide a method and apparatus for providing a fluid channel on a surface that a user desires to be thermally controlled or thermally regulated. The embodiments described herein provide a channel wherein the surface that is to be thermally regulated forms one side of the channel. The channels as described herein may be used to flow a thermal transfer fluid, such as a cooling fluid or a heated fluid. The channels as described herein provide an increased surface area for contact with the thermal transfer fluid and the thermal transfer fluid is in direct contact with the surface that is to be thermally regulated. For ease of description, embodiments described herein will be described with reference to flowing a cooling fluid adjacent a surface that is subject to high temperatures to remove heat from the surface. However, embodiments of the invention are not limited to removing excess heat and may be equally applicable to flowing a heated fluid to raise or maintain the temperature of the surface. 
     In some embodiments, a fluid channel may be formed on or coupled to semiconductor substrate process chambers. For example, suitable process chambers may include vacuum processing chambers, thermal processing chambers, plasma processing chambers, annealing chambers, deposition chambers, etch chambers, implant chambers, or the like. Examples of suitable chambers which may benefit from embodiments described herein include the QUANTUM® X implant chamber, and the CENTURA® RP EPI chamber, as well as other chambers available from Applied Materials, Inc. of Santa Clara, Calif. Embodiments described herein may be beneficially utilized on chambers available from other manufacturers as well. 
       FIG. 1A  is an isometric view of an enclosure or chamber  1  having a body including sidewalls  2  that define an interior volume  3 . In one embodiment, the interior volume is configured for containing a high temperature process. The chamber  1  includes a body having sidewalls  2  that define an interior volume  3  configured for a high temperature process. The high temperature process may be a deposition process, an annealing process or other processes where high temperatures are generated or maintained. The high temperature process within the interior volume transfers heat to the sidewalls  2 . 
     The heat transferred to the sidewalls  2  may be regulated for process control and/or to maintain the temperature of the sidewalls  2  within operational limits. To regulate the temperature of the sidewall  2 , heat from the sidewalls  2  is transferred by flowing a cooling fluid from a coolant source  4  through a cooling channel  5  disposed on the sidewall  2 . The cooling fluid may be water, de-ionized water (DIW), ethylene glycol, helium (He), nitrogen (N 2 ), argon (Ar) or other cooling fluids in liquid or gas phase. 
       FIG. 1B  is a cross-sectional view of one embodiment of a cooling channel  5  disposed on the sidewall  2  of the chamber of  FIG. 1A . The cooling channel  5  includes a cavity  6  formed by a surface  7  of the sidewall  2  and a convex member  8 . The convex member  8  is secured to the sidewall  2  by a continuous weld bead  9  and the cavity  6  is disposed between the continuous weld bead  9 . The continuous weld bead as used herein refers to a deposit of filler metal and/or an area of fusion produced by one or more passes of a welding device. The cooling fluid from the coolant source  4  flows in the cavity  6  in direct contact with the surface  7  of the sidewall  2  to transfer heat from the sidewall  2 . 
       FIG. 2A  is an isometric view of one embodiment of a first assembly  10 A illustrating an initial fabrication step to form a cooling channel  5  ( FIGS. 1A and 1B ). The first assembly  10 A includes a base or first plate  20  which may be joined with a chamber or form a sidewall  2  of a chamber  1  ( FIG. 1A ). The first plate  20  includes a surface  7  that is thermally conductive and in thermal communication with the extreme temperatures within the enclosure. Although the first plate  20  is rectangular and includes a flat or planar surface  7  as shown, the first plate  20  may be any irregular shape and the surface  7  may be non-planar. In one embodiment, the surface  7  forms an exterior surface of the first plate  20  after further fabrication and coupling with other sidewalls to form the chamber or enclosure. In this embodiment, the surface  7  of the first plate  20  is opposing a surface that is exposed to the interior of the chamber. Alternatively, the surface  7  may be an interior surface of the chamber after further fabrication. 
     The first plate  20  may be made of any thermally conductive material. Examples include steel, stainless steel, aluminum or other conductive material. In one embodiment, the material of the plate  20  is suitable to withstand temperatures in excess of 100 degrees Celsius. In one embodiment, the first plate  20  may be made of any material that is capable of being welded by a welding process, such as electron beam welding or laser welding, among other welding methods. 
     In a first step in the initial fabrication of a cooling channel, the first assembly  10 A includes a second plate  30  that is brought into proximity with the surface  7  of the first plate  20 . The second plate  30  may be positioned on the first plate to contact the surface  7 . After the second plate  30  has been positioned as desired, the first plate  20  and second plate  30  may be held together by clamps or tack welded along a perimeter  27  of the second plate  30 . The clamping and/or tack welding ensures contact between the first plate  20  and second plate  30  and prevents the second plate  30  from moving relative to the first plate  20 . 
     The second plate  30  may be made of any thermally conductive material that may be similar or different from the material of the first plate  20 . Examples include steel, stainless steel, aluminum or other conductive material suitable to withstand temperatures in excess of 100 degrees Celsius. In one embodiment, the second plate  30  may be made of a metallic material that may be welded by electron beam welding or laser welding, among other welding methods. Likewise, the second plate  30  may be shaped similarly to the shape of the first plate  20 . Alternatively, the shape of the second plate  30  may be different than the shape of the first plate  20 . Additionally, if the first plate  20  includes openings, cut-outs or structures protruding from the surface  7  (not shown), the second plate  30  may include openings, slots, chamfers, or cut-outs (not shown) formed therein configured to fit around or provide access to the openings, cut-outs or structures disposed on the first plate  20 . 
     In this embodiment, the second plate  30  is a sheet of material sized slightly smaller than the first plate  20 . In other embodiments, the second plate  30  may be larger than the first plate  20 . The second plate  30  is rectangular and includes a length and a width that is slightly smaller than the length and width of the first plate  20 . The second plate  30  is thinner than the first plate  20 . In one embodiment, the thickness of the first plate  20  is at least 3 times thicker than the thickness of the second plate  30 . 
       FIG. 2B  is an isometric view of a second assembly  10 B made from the first assembly  10 A, which illustrates an intermediate fabrication step to form a cooling channel  5  as shown in  FIG. 1A . After the second plate  30  is brought into proximity with and is at least partially contacting the surface  7 , a continuous weld bead  9  is laid in an elongated pattern  35  to join the first plate  20  and second plate  30 . The pattern  35  may be any desired pattern that facilitates a desired first fluid channel profile  37  on both of the first plate  20  and second plate  30 . The pattern  35  may be a suitable shape configured to provide efficient heat transfer from the surface  7 . For example, the pattern  35  may include at least one 180 degree curve or bend to form a “C” or “U” shape, form a serpentine shape or zigzag pattern, and combinations thereof. 
     In one embodiment, the first fluid channel profile  37  is defined as a width W between adjacent portions of the continuous weld bead  9 . In one example, the width W is the area between adjacent bead segments, such as bead segments  42 A and  42 B. In one embodiment, the area between the bead segments  42 A and  42 B, and any portion of the surface  7  and second plate  30  that is not joined, is a containment region (shown as  66  in  FIG. 2D ). The second assembly  10 B also shows the layout for an inlet fitting  50  and an outlet fitting  55  to be disposed in respective holes  45  formed in the second plate  30 . The inlet fitting  50  and outlet fitting  55  provide a fluid between the first plate  20  and second plate  30  to form the cooling channel as defined by the first fluid channel profile  37 . 
       FIG. 2C  is an isometric view of a third assembly  10 C made from the second assembly  10 B, which illustrates a final fabrication step to form a cooling channel  5  as shown in  FIG. 1A . In this embodiment, the inlet fitting  50  and outlet fitting  55  are coupled to the holes  45  (not shown in  FIG. 2B ). The inlet fitting  50  is connected to a pump  57  and the outlet fitting  55  is coupled to a fluid reservoir  58 . A valve  59  is disposed between the outlet fitting  55  and the fluid reservoir  58 . A fluid, such as water, is pumped from the fluid reservoir  58  through the inlet fitting  50  and into an interstitial space  44  ( FIG. 2D ) defined between the first plate  20  and the second plate  30  circumscribed by the continuous weld bead  9 . The valve  59  and/or pump  57  may be adjusted to build pressure in the interstitial space  44  defined between the first plate  20  and second plate  30 . A sufficient pressure is provided to deform the second plate  30  relative to the first plate  20  and form a second fluid channel profile  60 . 
       FIGS. 2D and 2E  are cross-sectional views of the first fluid channel profile  37  disposed on the first plate  20  and second plate  30 . Although the second plate  30  is welded to the first plate  20  by the continuous weld bead  9 , a containment region  66  is formed between the continuous weld bead  9  and portions of the surface  7  and second plate  30  that are not joined. The containment region  66  includes a gap or interstitial space  44  that remains between the surface  7  of the first plate  20  and the interior surface of the second plate  30 . The interstitial space  44  allows fluid to flow therein and subsequently deflect the portion of the second plate  30  to form a cavity therebetween.  FIG. 2E  shows the layout of the outlet fitting  55  which is coupled to the hole  45  as shown in  FIG. 3B . The outlet fitting  55  may be threaded or welded to the second plate  30 . If the outlet fitting  55  is welded to the second plate  30 , a spot face  62  may be formed in the surface  7  to prevent penetration of the weld to the first plate  20 . One or both of the hole  45  and spot face  62  may be formed in the second plate  30  and first plate  20 , respectively, prior to joining the second plate  30  with the first plate  20 . While not shown, the inlet fitting  50  may be coupled to the second plate  30  in the same manner as the outlet fitting  55 . 
       FIGS. 3A and 3B  are cross-sectional views of the second fluid channel profile  60  disposed on the first plate  20  and second plate  30 . During pressurization of the interstitial space  44  as described in  FIG. 2C , the second plate  30  is deflected and a cavity  6  is formed between an interior surface  65  of the second plate  30  and the surface  7  of the first plate  20 . After the second plate  30  is deflected to form a cavity  6  having a desired volume, a fluid channel  5  is formed on the surface  7  of the first plate  20 . The surface  7  of the first plate  20  may not be deflected and remain in the same shape due to the thickness of the first plate  20 . The second plate  30  includes an initial first thickness T′ but may be stretched during the deflection to a second thickness T″ between the continuous weld bead  9  that is less than the first thickness T′.  FIG. 3B  shows the outlet fitting  55  coupled to the hole  45  by a weld  68 . 
     In one embodiment, the interstitial space  44 , which is the area interior of the continuous weld bead  9  and portions of the surface  7  and second plate  30  that is not joined between the continuous weld bead  9 , includes a first volume or cross-sectional area and the cavity  6  that is formed includes a second volume or cross-sectional area that is at least 2 times greater than the first volume. For example, the interstitial space  44  may include a slight gap between the second plate  30  and the surface  7  to define a minimal cross-sectional area that is slightly greater than 0, such as about 0.1 cm 2 , and the cavity  6  that is formed thereafter may include a second cross-sectional area that is at least 200 times greater, for example about 20 cm 2 . In some embodiments, the cavity  6  that is formed includes a second volume or cross-sectional area that is at least 300 times greater than the first volume or cross-sectional area. 
     While the embodiments described above are directed to a rectangular or cube-shaped chamber  1  as shown in  FIG. 1A  with rectangular and/or planar sidewalls, alternative embodiments may be utilized to form fluid channels in chambers or enclosures having other shapes. For example, prior to joining the first plate  20  with the second plate  30 , the second plate  30  may be bent using a sheet metal brake to form corners or angles in the second plate  30  that substantially match the corners or angles of the chamber or enclosure. Additionally, if the chamber or enclosure includes non-linear or arcuate sidewalls, the second plate may be rolled to substantially match the curvature of the sidewalls prior to joining the second plate  30  to the first plate  20 . Alternatively, if the chamber or enclosure formed from a first plate  20  is to be cylindrical in final form, a planar second plate  30  may be joined to a planar first plate  20  and the first fluid channel profile  37  may be formed by the continuous weld bead while both plates  20  and  30  are flat. Thereafter, both the first plate  20  and second plate  30  may be rolled to a desired radius and the first plate  30  may be seam welded. After rolling both plates  20  and  30 , the inlet fitting and outlet fitting may be coupled to the containment region and deflected to form a fluid channel. 
       FIG. 4  is a schematic, cross-sectional diagram of vacuum processing chamber  402  that may be configured for a deposition or an etch process on a substrate  414 . In one embodiment, the vacuum processing chamber  402  includes a chamber body  410  having conductive chamber sidewall  430  that includes portions that are non-linear or arcuate. One example of a vacuum processing chamber  402  in which embodiments described herein may be beneficially utilized is an ENABLER® processing chamber available from Applied Materials, Inc., of Santa Clara, Calif. It is also contemplated some embodiments described herein may be used to advantage in other processing chambers configured for other process, including those from other manufacturers. 
     The chamber body  410  includes a lid  470  and a bottom  98  coupled to the conductive chamber sidewall  430  to enclose an interior volume  478  defined within the chamber body  410 . The conductive chamber sidewall  430  is connected to an electrical ground  434  and at least one solenoid segment  412  is positioned exterior to the conductive chamber sidewall  430 . The solenoid segment(s)  412  may be selectively energized by a DC power source  454  that is capable of producing at least 5V to provide a control metric for plasma processes formed within the vacuum processing chamber  402 . A ceramic liner  431  is disposed within the interior volume  478  to facilitate cleaning of the chamber  402 . The byproducts and residue of a deposition or an etch process may be readily removed from the liner  431  at selected intervals. 
     A substrate support pedestal  416  is disposed on the bottom  98  of the vacuum processing chamber  402  below a gas diffuser or showerhead  432 . A process region  480  is defined within the interior volume  478  between the substrate support pedestal  416  and the showerhead  432 . A port  97  may be formed in the conductive chamber sidewall  430  to facilitate transfer of the substrate to the process region  480 . The substrate support pedestal  416  may include an electrostatic chuck  426  for retaining a substrate  414  on a surface  49  of the pedestal  416  beneath the showerhead  432  during processing. The electrostatic chuck  426  is controlled by a DC power supply  420 . The support pedestal  416  may be coupled to a radio frequency (RF) bias source  422  through a matching network  424 . The bias source  422  is generally capable of producing a RF signal having a tunable frequency of 50 kHz to 13.56 MHz and a power of between 0 and 5000 Watts. Optionally, the bias source  422  may be a DC or pulsed DC source. 
     The interior of the vacuum processing chamber  402  is a high vacuum vessel that is coupled to a vacuum pump  436  through an exhaust port  435  formed through the conductive chamber sidewall  430  and/or the chamber bottom  98 . A throttle valve  427  disposed in the exhaust port  435  is used in conjunction with the vacuum pump  436  to control the pressure inside the vacuum processing chamber  402 . The showerhead  432  includes at least two gas distributors  460 ,  462 , a mounting plate  428  and a gas distribution plate  464 . The gas distributors  460 ,  462  are coupled to one or more gas panels  438  through the lid  470  of the vacuum processing chamber  402 . The flow of gas through the gas distributors  460 ,  462  may be independently controlled. Although the gas distributors  460 ,  462  are shown coupled to a single gas panel  438 , it is contemplated that the gas distributors  460 ,  462  may be coupled to one or more shared and/or separate gas sources. Gases provided from the gas panel  438  are delivered into a region  472  defined between the plates  428 ,  464 , then exit through a plurality of holes  468  formed through the gas distribution plate  464  into the process region  480  where a plasma is formed. The showerhead  432  is adapted to deliver gas into the process region  480  with an asymmetry that offsets the asymmetric effects of the chamber conductance on plasma location and/or the delivery of ions and/or reactive species to the surface of the substrate during processing. The mounting plate  428  is coupled to the lid  470  opposite the support pedestal  416 . The mounting plate  428  is fabricated from or covered by a RF conductive material. The mounting plate  428  is coupled to a RF source  418  through an impedance transformer  419  (e.g., a quarter wavelength matching stub). The source  418  is generally capable of producing a RF signal having a tunable frequency of about 162 MHz and a power between about 0 and 2000 Watts. The mounting plate  428  and/or gas distribution plate  464  is powered by the RF source  418  to promote and/or maintain the plasma formed from the process gas present in the process region  480  of the vacuum processing chamber  402 . 
     The plasma formed in the process region  480  may reach temperatures in excess of 400 degrees Celsius. The temperature in the process region  480  is controlled or supplemented by various temperature control devices that are disposed in or around the vacuum processing chamber  402 . The support pedestal  416  may include inner and outer temperature regulating zones  474 ,  476  to control the temperature of the support pedestal  416  and the substrate  414  supported thereon. Each of the inner and outer temperature regulating zones  474 ,  476  may include at least one temperature regulating device, such as a resistive heater or a conduit for circulating coolant, so that the radial temperature gradient of the substrate disposed on the pedestal  416  may be controlled. To remove or provide heat to the conductive chamber sidewall  430 , a fluid channel may be coupled to the conductive chamber sidewall  430  as described below. 
       FIG. 5A  is an isometric view of another embodiment of a first assembly  15 A illustrating an initial fabrication step to form a cooling channel on the vacuum processing chamber  402  of  FIG. 4 . The first assembly  15 A is shown in an initial stage in the manufacture of the vacuum processing chamber  402  such that the material to form the conductive chamber sidewall  430  of the vacuum processing chamber  402  is depicted as a first member  520  that is in the general shape of a cylinder. The first member  520  includes the surface  7  which forms one side of the fluid channel. A second member  530  is shown adjacent the first member  520  that includes a shape that is substantially similar to the shape of the first member  520 . The first member may be made of a conductive metal, such as aluminum or stainless steel as described above in reference to the first plate  20  and the second member  530  may be a sheet of material as described above in reference to the second plate  30 . In one embodiment, the second member  530  has been rolled to include a radius that substantially matches a radius of the surface  7 . 
     In this embodiment, a plurality of spot faces  62  (only one is shown in this view) have been pre-formed in the first member  520  and a plurality of holes  45  that align with the spot faces  62  have been pre-formed in the second member  530 . In a first step in the initial fabrication of a cooling channel, the second member  530  is brought into proximity with the surface  7  of the first member  520 . The second member  530  may be positioned on the first member  520  to be in contact with the surface  7 . After the second member  530  has been positioned as desired on the first member  520 , the first member  520  and second member  530  may be held together by clamps or tack welded along a perimeter  27  of the second member  530 . The clamping and/or tack welding ensures contact between the first member  520  and second member  530  and prevents the second member  530  from moving relative to the first member  520 . 
       FIG. 5B  is an isometric view of a second assembly  15 B made from the first assembly  15 A, which illustrates an intermediate fabrication step to form a cooling channel. After the second member  530  is brought into proximity with and in contact with the surface  7 , a continuous weld bead  9  is laid in a pattern  535  to join the first member  520  and second member  530 . The pattern  535  may be a pattern selected to regulate the temperature of the chamber wall as desired. The pattern  535  defines a first fluid channel profile  537  on both of the first member  520  and second member  530 . The second assembly  15 B also shows the layout for an inlet fitting  50  and an outlet fitting  55  to be disposed in respective holes  45  formed in the second member  530 . The inlet fitting  50  and outlet fitting  55  provide a fluid between the first member  520  and second member  530  to form the cooling channel as defined by the first fluid channel profile  537 . In one embodiment, portions of the second member  530  outside of the first fluid channel profile  537  and the continuous weld bead  9  may be trimmed off. 
       FIG. 5C  is an isometric view of a third assembly  15 C made from the second assembly  15 B, which illustrates a final fabrication step to form a cooling channel  5 . In this embodiment, the inlet fitting  50  and outlet fitting  55  are coupled to the holes  45  (not shown in this view). The inlet fitting  50  is connected to a pump  57  and the outlet fitting  55  is coupled to a fluid reservoir  58 . A valve  59  is disposed between the outlet  55  and the fluid reservoir  58 . A fluid, such as water, is pumped from the fluid reservoir  58  through the inlet fitting  50  and into an interstitial space  44  ( FIG. 6 ) between the first member  520  and second member  530 . When a sufficient pressure is reached in the interstitial space  44 , the second member  530  is deformed outward to form a second fluid channel profile  560 . 
       FIGS. 6 and 7  are respective cross-sectional views of the first fluid channel profile  537  and second fluid channel profile  560  disposed on the first member  520  and second member  530 . During pressurization of the interstitial space  44  as described in  FIG. 5C , the second member  530  is deflected and a cavity  6  is formed between an interior surface  65  of the second member  530  and the surface  7  of the first member  520 . After the second member  530  is deflected to create a cavity  6  having a desired volume, a fluid channel  5  is formed on the surface  7  of the first member  520 . The surface  7  of the first member  520  may not be deflected and remain in the same arcuate shape due to the thickness of the first member  520  relative to the thickness of the second member  530 . As such, the second member  530  includes an initial first thickness T′ but may be stretched during the deflection to a second thickness T″ between the continuous weld bead  9  that is less than the first thickness T′. 
     After the fluid channel  5  has been formed on the first member  520 , further fabrication of the vacuum processing chamber  402  may commence. The inlet fitting  50  and outlet fitting  55  used for providing a fluid to the interstitial space  44  for deflection may be coupled to the coolant source  4  ( FIG. 1A ) to provide a cooling fluid to the fluid channel  5  to transfer heat from the surface  7  in a manner that regulates the temperature of the first member  520 . 
       FIG. 8  is a flow chart of a method  800  for forming a fluid channel  5 . At  810 , a base or first member having a surface  7  is provided, such as the first plate  20 . Step  820  describes coupling the first member to a second member, such as the second plate  30 , by a continuous weld bead. The penetration of the continuous weld bead  9  should be at least equal to or greater than the thickness of the second member. The continuous weld bead forms a first fluid channel profile that provides a joining of the first member and second member such that a containment region  66  is formed interior of the continuous weld bead. The first fluid channel profile may include opposing weld beads in a straight and parallel relation, include one or more bends, one or more U-shaped or angled turns, or any pattern that provides a containment region interior of the continuous weld bead. 
     At  830 , a fluid is injected into the containment region. The fluid may be water that is provided to an inlet fitting  50  coupled to the second member and flows to an outlet fitting  55  coupled to the second member. In order to remove any gas, such as air, that may be present in the containment region  66 , the outlet fitting  55  may be elevated above the inlet fitting  50  to allow air to escape through the outlet fitting  55  during the fluid injection. At  840 , the fluid is pressurized in the containment region by a pump and/or a valve coupled to the outlet fitting  55 . The pressure of the water may be varied until the second member is inflated or deformed. The deformation may be continuously monitored until the second member has been deformed a suitable amount. The fluid injection may then be discontinued and the pump and valve removed from the inlet fitting and outlet fitting. The inlet fitting and outlet fitting may then be utilized to provide a heat transfer fluid to the formed fluid channel. 
     EXAMPLE  
     A fluid channel  5  was formed on a semiconductor substrate processing chamber according to embodiments described herein. The first member, which was a sidewall of the processing chamber in a flat or planar shape, was grade  304  stainless steel having a thickness of about 0.25 inches (6.35 mm). The second member was a sheet of grade  304  stainless steel having a thickness of 0.029 inches (0.736 mm). Spot faces of about 0.030 inches (0.762 mm) deep were formed in the first member and holes for the inlet fitting and outlet fitting were formed in the second member. While both the first member and the second member were substantially flat, the second member was brought into contact with the first member and the perimeter of the second member was tacked to the first member. 
     A continuous weld bead was laid in a desired pattern to join the first member and second member. An X/Y table was used to move the first member and second member to lay the continuous weld bead. A first fluid channel profile was formed by the continuous weld bead having a width between adjacent weld beads of about 50 mm. The previously formed holes for the inlet fitting and outlet fitting were within the first fluid channel profile. After the first fluid channel profile was formed, the first member and second member were rolled to a desired radius and a seam weld was made to form a cylindrical sidewall. 
     The inlets and outlets were welded to the previously formed holes in the second member. A fluid reservoir of water was used having a capacity of about 5 gallons. A pump capable of providing about 2000 psi (13.8 MPa) of pressure was coupled to the inlet fitting with a length of copper tubing. A metering valve was coupled to the outlet fitting by another length of copper tubing and the metering valve was fully opened. The first and second members were tilted to elevate the outlet fitting above the remainder of the assembly to allow air to escape as water was flowed through the inlet fitting. After air was purged from the outlet fitting, the metering valve was closed to allow the pump to pressurize the interstitial space defined by the first fluid channel profile. Deflection of the second member was monitored until a desired second fluid channel profile was created by the pressurized water. In this example, the cross-sectional area of the second fluid channel profile was about 196 cm 2 , which would be substantially equal to the cross-sectional area of a tube having a ½ inch (12.7 mm) inside diameter. The pump was turned off and the pump and metering valve was disconnected from the inlet fitting and outlet fitting. The cylindrical assembly having the fluid channel formed therein was coupled with other components to form a semiconductor substrate processing chamber. The inlet fitting and outlet fitting was coupled to a fluid source to provide cooling fluid to the fluid channel and thus transfer heat from the semiconductor substrate processing chamber. 
     In the embodiments described above, a method of forming a fluid channel  5  is provided. The method described above provides a fluid channel that is formed in-situ on a chamber wall during an initial stage of chamber fabrication. Forming of the fluid channel as described above requires no specialized forms, molds or dies that may be needed to form conventional channels. The fluid channel  5  described above is less labor intensive and can be fabricated in less time than conventional methods, such as gun drilling and welding or clamping tubing to a sidewall. The method as described above is also less expensive than the conventional methods. In the example described above, a savings of greater than 50 percent was realized as compared to welded or clamped-on tubing. Additionally, since the surface to be thermally regulated is in direct contact with the heat transfer fluid, the fluid channel  5  provides a very efficient means for temperature control. 
     While the foregoing is directed to embodiments of the 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.