Abstract:
Apparatus and system for mixing gas comprising a first valve coupled to a first conduit controlling flow of a first gas, a second valve coupled to a second conduit controlling flow of a second gas, a controller controlling the valves, a base block with a first gas input coupled to the first conduit, a second gas input coupled to the second conduit and an output opening, a mixing chamber formed within the base block, wherein the mixing chamber is coupled to the first gas input and the second gas input to receive input gases, an inner block disposed within the mixing chamber, the inner block including a body with an inner volume and one or more perimeter holes formed through the body coupling the mixing chamber to the inner volume of the inner block; and a gas outlet configured to flow gas through the output opening of the base block.

Description:
FIELD 
       [0001]    Embodiments of the present invention generally relate to semiconductor substrate processing. 
       BACKGROUND 
       [0002]    In semiconductor processing equipment, multiple gas species are often input into a common manifold before being introduced to the reaction chamber. A homogeneous mixture of the gas species is typically required to ensure substrate process uniformity and repeatability. However, stand alone component gas mixers adversely affect the size of the gas panel, are difficult to retrofit, increase response characteristics and can cause condensation of low vapor pressure gases. 
         [0003]    Therefore, the inventors have provided improved apparatus for enhancing the mixing of gaseous species in semiconductor processing equipment. 
       SUMMARY 
       [0004]    A compact gas mixer for enhancing the mixing of gaseous species in semiconductor processing equipment are provided herein. In some embodiments, the compact gas mixer includes a base block including a first gas input, a second gas input, and an output opening, with at least two inputs corresponding to at least two gases, the base block forming a mixing chamber formed within the base block, wherein the mixing chamber is fluidly coupled to the first gas input and the second gas input to receive input gases. The mixer further includes an inner block disposed within the mixing chamber, the inner block comprising: a body having an inner volume, one or more perimeter holes formed through the body fluidly coupling the mixing chamber to the inner volume of the inner block. A gas outlet is configured to flow gas through the output opening of the base block. 
         [0005]    In some embodiments, a compact gas mixer includes a base block including a mixing chamber disposed within the base block, a first gas input disposed on a first side of the base block and coupled to the mixing chamber, a second gas input disposed on an opposing second side of the base block and coupled to the mixing chamber, a pass through conduit disposed through the base block from the first side to the second side and not coupled to the mixing chamber, and an output opening disposed on an end of the base block between the first side and the second side; and an inner block disposed within and spaced apart from walls of the mixing chamber, the inner block having an inner volume and a gas outlet coupled to the inner volume to flow gas from the inner volume through the output opening of the base block, wherein the inner block further includes one or more perimeter holes formed through the body and fluidly coupling the mixing volume of the mixing chamber to the inner volume of the inner block to provide a fluid path from the first and second gas inputs to the output opening. 
         [0006]    In some embodiments, a system for mixing gas may include a first valve coupled to a first conduit controlling flow of a first gas and a second valve coupled to a second conduit controlling flow of a second gas. The system further includes a base block with a first gas input coupled to the first conduit, a second gas input coupled to the second conduit and an output opening, and a mixing chamber formed within the base block, wherein the mixing chamber is fluidly coupled to the first gas input and the second gas input to receive input gases. An inner block disposed within the mixing chamber, the inner block comprising: a body having an inner volume, one or more perimeter holes formed through the body fluidly coupling the mixing chamber to the inner volume of the inner block; and a gas outlet configured to flow gas through the output opening of the base block. 
         [0007]    Other and further embodiments of the present invention are described below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Embodiments of the present invention, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the invention depicted 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. 
           [0009]      FIG. 1A  depicts an isometric view of a mixer in accordance with some embodiments of the present invention; 
           [0010]      FIG. 1B  depicts a schematic side cross-section view of the mixer in accordance with some embodiments of the present invention in  FIG. 1A ; 
           [0011]      FIGS. 2A and 2B  depict two isometric views of an inner block of the mixer in accordance with some embodiments of the present invention; 
           [0012]      FIGS. 3A and 3B  depict two isometric views of an outlet block of the mixer in accordance with some embodiments of the present invention; 
           [0013]      FIGS. 4A and 4B  depict two isometric views of and eccentric outlet block in accordance with some embodiments of the present invention; and 
           [0014]      FIG. 5  depicts schematic block diagram showing an exemplary gas flow control system in accordance with some embodiments of the present invention. 
       
    
    
       [0015]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
       DETAILED DESCRIPTION 
       [0016]    Embodiments of the present invention enhance homogeneous mixing of gaseous species in a compact form and are described below. 
         [0017]      FIG. 1A  depicts an isometric view of a compact mixer system  100  in accordance with some embodiments of the present invention. Note, phantom lines may be shown for clarity purposes. In some embodiments, the compact mixer system  100  may include a base block  105 , an inner block  165 , and an outlet block  170 . In some embodiments, the base block  105  includes a first bottom input opening  110 , a second bottom input opening  150 , a top output opening  125 , a top input opening  140 , a mixing chamber (e.g. manifold)  145 , and an outlet opening  135 . A first gas  115  can be flowed into the base block  105  via first bottom input opening  110 , and a second gas  155  can be flowed into the base block  105  via second bottom input opening  150 . The first and second bottom input openings  110 ,  150  in some embodiments may be coupled input conduits (not shown) that supply the first and second gases  115 ,  155  to base block  105 . In such embodiments, base block openings using o-rings or other types of seals to prevent gas leakage. In some embodiments, the compact mixer may be referred to as a sandwich mixer. 
         [0018]    In some embodiments, the base block  105  may include a pass through conduit  120  that fluidly couples the first bottom input opening  110  to the top output opening  125 . In some embodiments, the first gas  115  flows through the base block  105  at the first bottom input opening  110  to a top output opening  125  via pass through conduit  120  prior to reaching a first valve  130 . In some embodiments, the pass through conduit  120  may bent or angled to avoid any interference with the gas mixing chamber  145  volume. The first valve  130  may be controlled by a controller (shown in  FIG. 4 ) to regulate the amount of the first gas  115  that is introduced into the mixing chamber  145  to the top input opening  140 . In an alternative embodiment, the first gas  115  may be input directly to the base block  105  and the mixing chamber  145  via the top input opening  140  from the first valve  130 . In such an embodiment, there is no pass through conduit  120  and the first gas is directly injected into the mixing chamber  145 . 
         [0019]    The second bottom input opening  150  allows gas to enter the mixing chamber  145  controlled by a second valve  160 . The second valve  160  may be controlled by a controller (shown in  FIG. 5 ) to regulate the amount of the second gas  155  that is introduced into the mixing chamber  145  through the bottom input opening  150 . Gases in the mixing chamber  145  may be comprised of a single gas or mixed gases depending on the control of the first valve  130  and the second valve  160 . In some embodiments, the first valve  130  may control an input of an inert gas and the second valve  160  may control input of a toxic gas in the mixing chamber  145 . In some embodiments, the gas or gas mixture in the mixing chamber  145  passes to the inner block  165  through a series of perimeter ventilation holes  180  leading to the interior (comprising a blind hole) of the inner block  165 . The details of the inner block  165  will be discussed further below with  FIGS. 2A and 2B . The gas mixture leaves the interior of the inner block  165  via outlet hole  175  on the outlet block  170 . In some embodiments, the perimeter ventilation holes may be substantially circular or elliptical. 
         [0020]    In some embodiments, the openings  125  and  140  at the top of the mixer  100  may be retrofitted to couple to another block that may contain valve  130 . The mixer  100  is thus modular for retrofitting into larger devices. In embodiments described above, the openings ( 110 ,  125 ,  140 ,  150 ) determine gas flow input directions while the outlet hole  175  would be the output flow. 
         [0021]    In some embodiments, base block  105  may have a height  190  of about 10 mm to about 20 mm. In some embodiments, base block  105  may have a width  192  of about 1 mm to about 10 mm. In some embodiments, base block  105  may have a depth  191  of about 1 mm to about 10 mm. In some embodiments, the base block  105  may provide a gas flow rate output at the outlet hole  175  of about 0.001 slm to about 100 slm. 
         [0022]    Exemplary embodiments of compact mixer system  100  may advantageously provide one or more of the following benefits: minimum impact on the overall design footprint (which allows easy retrofit on existing designs and minimizes any impact on the size of the enclosure), minimum impact on the manifold volume (which minimizes impact on the response characteristics of the gas delivery system), and minimum impact on the differential pressure (which minimizes impact on response characteristics and minimizes issues associated with low vapor pressure gases). Exemplary embodiments of compact mixer system  100  may be retrofitted to existing systems through surface mounting seals to prevent gas leakage and to retain the compact mixer system  100  in place. 
         [0023]      FIG. 1B  depicts a side cross-section view of the mixer system  100  in accordance with some embodiments of the present invention in  FIG. 1A . In some embodiments, the compact mixer system  100  may includes the base block  105 , the inner block  165 , and the outlet block  170 . In some embodiments, the inner block  165  comprises an inner chamber  168  coupled to the outlet hole  175 . 
         [0024]    In some embodiments, the base block  105  may include a pass through conduit  120  that fluidly couples the first bottom input opening  110  to the top output opening  125 . In some embodiments, the first gas  115  flows through the base block  105  and controlled by the first valve  130  to regulate the amount of the first gas  115  that is introduced into the mixing chamber  145  via a first inlet opening  172  coupled to the top input opening  140  (e.g. via a conduit). In an alternative embodiment, the first gas  115  may be input directly to the base block  105  and the mixing chamber  145  via the top input opening  140  from the first valve  130 . 
         [0025]    The second bottom input opening  150  (shown in  FIG. 1A ) allows gas to enter the mixing chamber  145  as controlled by a second valve  160  via a second inlet opening formed in the mixing chamber  145 . The second valve  160  may be controlled by a controller (shown in  FIG. 5 ) to regulate the amount of the second gas  155  that is introduced into the mixing chamber  145  through the bottom input opening  150 . Gases in the mixing chamber  145  may be comprised of a single gas or mixed gases depending on the control of the first valve  130  and the second valve  160 . In some embodiments, the first valve  130  may control an input of an inert gas and the second valve  160  may control input of a toxic gas in the mixing chamber  145 . 
         [0026]    The first gas  115  and second gas  155  mix in the mixing chamber to ultimately form and output the mixed gas depicted as arrow  185 . In some embodiments, the gas or gas mixture in the mixing chamber  145  passes to the inner block  165  through a series of perimeter ventilation holes  180  coupled to gas channels  182  formed within the inner block  165 . The gas channels  182  lead to the interior inner chamber  168  (comprising the blind hole) of the inner block  165 . The details of the inner block  165  will be discussed further below with  FIGS. 2A and 2B . The mixed gas  185  passes from the mixing chamber  145  to an inner chamber  168  via ventilation holes  180  and gas channels  182  formed in the inner block  165 . The mixed gas leaves the inner chamber  168  of the inner block  165  via outlet hole  175  on the outlet block  170 . In some embodiments, the gas channels  182  may be sloped or inclined at a selected angle to for greater gas fluidity. 
         [0027]      FIGS. 2A and 2B  depict two isometric views of the inner block  165  of the mixer in  FIGS. 1A and 1B  in accordance with some embodiments of the present invention. In  FIG. 2A , the inner block  165  is substantially cylindrical with an gas outlet end  200  and a closed end  205  that form an inner chamber  168  (as shown in  FIG. 2B ) of the inner block  165 . Although shown and described as substantially cylindrical, in some embodiments, the inner block  165  may be spherical, rectangular, or any other suitable geometries that provide mixing capabilities described herein. The inner block  165  further comprises a first beveled edge  220 , a second beveled edge  225 , and a collar  210 . The first beveled edge  220  proximate the closed end  205  and the second beveled edge  225  distal to the closed end  205 . The second beveled edge  225  comprising the series of perimeter ventilation holes  180  allowing gas to enter the inner chamber  168  of the inner block  165 . In some embodiments, the perimeter ventilation holes  180  are angled holes at an inclined angle of about 15 to 17.5 degrees for maximum flow rate and to create a small vortex. The small size of the perimeter ventilation holes  180  ensures entering gases contact and reflect off of the closed end  205  before leaving the gas outlet end  200 . The collar  210  couples to the outlet block  170  that will be further discussed with respect to  FIGS. 3A and 3B . 
         [0028]      FIG. 2B  illustrates an alternative isometric view of the inner block  165  depicting the perimeter ventilation holes  180  forming channels to the inner chamber  168  via through holes  230 . The gas entering the inner chamber  168  exit the inner block through the collar that forms around the gas outlet end  200  leading to outlet block  170 . 
         [0029]      FIGS. 3A and 3B  depict two isometric views of the outlet block of the mixer in  FIGS. 1A and 1B  in accordance with some embodiments of the present invention.  FIG. 3A  provides an exterior view of the outlet block  170 . In an embodiment, the outlet block  170  is substantially circular with flat surface  310 . The outlet collar  300  may have an internal diameter  308  selected based on the gas flow rate desired. Extending from the flat surface  310  is a raised collar  300  of an exemplary width that is also substantially circular and forms the outlet through hole  175 . The outlet through hole  175  in some embodiments will be coupled to a flow rate controller that will be discussed in further detail below with respect to  FIG. 4 . In some embodiments, the outlet block is formed from one piece. 
         [0030]      FIG. 3B  provides an interior view of the outlet block  170 . The interior of the outlet block  170  comprises a first contoured ring  315  having a width  317  and a second contoured ring  325  having a width  322  that are separated by a flattened area  320  having a width  318 . The widths  317 ,  318  and  322  may be selected based on the outlet opening  135  configuration in addition to machining and space constraints and requirements. The flattened area  320  couples with the flat edge of the collar  210 . The interior of the outlet block  170  further includes an interior collar  330  with a smaller diameter  335  than the collar  210  of the inner block  165 . The interior collar  330  may have a height  324  and a width  326  selected based on the collar  210  configuration such that it is small enough to fit into the collar  210  of the inner block  165 . In some embodiments, the outlet block  170  is welded to the collar  210  of the inner block  165  that is also welded to the mixer  100 . 
         [0031]      FIGS. 4A and 4B  depict two isometric views of the outlet block of the mixer in  FIGS. 1A and 1B  in accordance with some embodiments of the present invention.  FIG. 4A  provides an exterior view of eccentric outlet bock  400  that may replace the outlet block  170  of  FIGS. 1A and 1B . The eccentric design allows for a reduction in fittings to retrofit with other devices (such as mixers) and the angle of through holes  425  and  450  is selected based upon the location of the retrofitting. In some embodiments, the eccentric outlet block  400  is substantially circular with flat exterior surface  407 . An eccentric outlet collar  405  may be mounted to (or formed thereon) the exterior surface  407 . One perimeter edge  409  of the eccentric outlet collar  405  is adjacent to the perimeter of the eccentric outlet block  400 . A distal perimeter edge  411  of the eccentric outlet collar  405  having a distance  420  in some embodiments of 6.8 mm from the opposite radial end of the eccentric outlet block  400 . Located within the interior diameter  430  is an elliptical outlet through hole  425  that in some embodiments may be the through hole  175  in  FIGS. 1A and 1B . 
         [0032]    The eccentric outlet through hole  425  in some embodiments will be coupled to a flow rate controller that will be discussed in further detail below with respect to  FIG. 4 . In some embodiments, the eccentric outlet block  400  is formed from one piece. 
         [0033]      FIG. 4B  provides a simplified interior view of the eccentric outlet block  400 . The interior of the eccentric outlet block  400  comprises an centrally located interior eccentric collar  445  with an elliptical interior outlet through hole  450 . 
         [0034]    The interior of the eccentric outlet block further comprises a first contoured ring  460  and a second contoured ring  465  that are separated by a flattened area  470 . The flattened area  470  couples with the flat edge of the collar  210 . The interior of the eccentric outlet block  400  further includes the interior eccentric collar  445  with a smaller diameter  475  than the collar  210  of the inner block  165 . The size of the interior eccentric collar  445  of the eccentric outlet block  400  is small enough to fit into the collar  210  of the inner block  165 . In some embodiments, the outlet block  170  is welded to the collar  210  of the inner block  165  that is also welded to the mixer  100 . 
         [0035]      FIG. 5  depicts schematic view of the mixer in  FIGS. 1A and 1B  in accordance with some embodiments of the present invention.  FIG. 5  is an embodiment of a system  500  using the compact mixer  100  of  FIGS. 1A and 1B . The system  500  comprises a controller  515  controlling the first valve  130  that controls the flow of the first gas  115  into a mixing chamber  145  and the second valve  160  that controls the flow of the second gas  155  into the mixing chamber  145 . The controller  515  comprising a microcontroller, memory, actuators, and the like to selectively actuate the first valve  130  and the second valve  160 . The mixing chamber  145  outputting gas to the flow rate controller (FRC)  505 . The FRC  505  outputting through a series of BCR fittings/connections  510 . In some embodiments the FRC  505  may connect via VCR fittings. 
         [0036]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.