Deposition method and apparatus

Abstract

A method of depositing a material on a substrate comprises placing a substrate into a process space in fluidic communication with a Gaede pump stage (GPS). A precursor gas is then injected into the process space while injecting a draw gas at a draw gas flow rate into the GPS such that the injected precursor gas achieves a precursor pressure and a precursor gas flow rate in the process space. Subsequently, substantially all of the precursor gas remaining in the process space is swept from the process space by injecting a sweep gas into the process space such that the injected sweep gas achieves a sweep pressure and sweep gas flow rate in the process space. The precursor pressure is higher than the sweep pressure, and the precursor gas flow rate is lower than the sweep gas flow rate.

What is claimed is: 
     
         1 . An apparatus for depositing a material on a substrate, the apparatus comprising:
 a process space adapted to hold the substrate;   a Gaede pump stage (GPS) in fluidic communication with the process space; and   one or more gas manifolds adapted to inject a precursor gas into the process space while injecting a draw gas at a draw gas flow rate directly into the GPS such that the injected precursor gas achieves a precursor pressure and a precursor gas flow rate in the process space, and to sweep substantially all of the precursor gas remaining in the process space from the process space by injecting a sweep gas into the process space such that the injected sweep gas achieves a sweep pressure and sweep gas flow rate in the process space;   wherein the precursor gas flow rate is lower than the sweep gas flow rate.   
     
     
         2 . The apparatus of  claim 1 , wherein the precursor pressure is higher than the sweep pressure. 
     
     
         3 . The apparatus of  claim 1 , wherein the one or more gas manifolds are further adapted to inject a second precursor gas into the process space while injecting a second draw gas at a second draw gas flow rate directly into the GPS such that the injected second precursor gas achieves a second precursor pressure and a second precursor gas flow rate in the process space, the second precursor gas flow rate being lower than the sweep gas flow rate. 
     
     
         4 . The apparatus of  claim 3 , wherein the second precursor pressure is higher than the sweep pressure. 
     
     
         5 . The apparatus of  claim 3 , wherein the second draw gas has substantially the same composition as the draw gas. 
     
     
         6 . The apparatus of  claim 3 , wherein the second draw gas flow rate is substantially the same as the draw gas flow rate. 
     
     
         7 . The apparatus of  claim 3 , wherein the second precursor pressure differs from the precursor pressure. 
     
     
         8 . The apparatus of  claim 1 , wherein the draw gas flow rate is higher than the sweep gas flow rate. 
     
     
         9 . The apparatus of  claim 1 , wherein the GPS displays a lower compression ratio while the precursor gas is injected into the process space than it does while the sweep gas is injected into the process space. 
     
     
         10 . The apparatus of  claim 1 , wherein the GPS comprises only one impeller. 
     
     
         11 . The apparatus of  claim 1 , wherein the GPS comprises a plurality of impellers. 
     
     
         12 . The apparatus of  claim 11 , wherein two of the plurality of impellers rotate in opposite directions. 
     
     
         13 . The apparatus of  claim 1 , wherein the GPS comprises an impeller laterally surrounded by a ring-shaped enclosure. 
     
     
         14 . The apparatus of  claim 13 , wherein at least one of the one more gas manifolds is adapted to inject the draw gas into a gap between the impeller and the ring-shaped enclosure. 
     
     
         15 . The apparatus of  claim 1 , wherein the GPS comprises an impeller that includes a plurality of blades that span radially from an inner hub to an outer rim. 
     
     
         16 . The apparatus of  claim 15 , wherein a plurality of magnets are distributed along the outer rim of the impeller. 
     
     
         17 . The apparatus of  claim 15 , wherein the impeller may be made to rotate by providing electrical signals to a plurality of electromagnetic coils distributed proximate to the outer rim of the impeller. 
     
     
         18 . The apparatus of  claim 17 , wherein the impeller may be further made to shift laterally by providing electrical signals to the plurality of electromagnetic coils. 
     
     
         19 . The apparatus of  claim 15 , wherein the impeller comprises a plurality of holes in its outer rim. 
     
     
         20 . The apparatus or  claim 1 , wherein the GPS comprises a ring-shaped impeller, the ring-shaped impeller laterally surrounding and adapted to rotate around one or more other elements of the apparatus. 
     
     
         21 . The apparatus of  claim 20 , wherein the ring-shaped impeller laterally surrounds and is adapted to rotate around a stage adapted to hold the substrate. 
     
     
         22 . The apparatus of  claim 1 , further comprising an abatement space in fluidic communication with the GPS, the abatement space comprising an abatement surface on which the precursor gas may be converted to a film on the abatement surface in the presence of an abatement gas. 
     
     
         23 . The apparatus of  claim 22 , further comprising:
 an abatement GPS in fluidic communication with the abatement space; and   an abatement draw gas manifold adapted to inject an abatement draw gas into the abatement GPS.   
     
     
         24 . The apparatus of  claim 1 , further comprising a roots blower pump. 
     
     
         25 . A Gaede pump stage (GPS) comprising:
 an impeller comprising a plurality of blades that span radially from an inner hub to an outer rim;   an enclosure laterally surrounding the impeller;   a plurality of permanent magnets attached to the outer rim of the impeller; and   a plurality of electromagnetic coils attached to the enclosure and disposed proximate to the outer rim of the impeller, the plurality of electromagnetic coils adapted to levitate the impeller, rotate the impeller, and center the impeller laterally within the enclosure in response to received electrical signals.   
     
     
         26 . The GPS of  claim 25 , wherein the GPS comprises only a single impeller. 
     
     
         27 . The GPS of  claim 25 , wherein the GPS comprises a plurality of impellers. 
     
     
         28 . The GPS of  claim 27 , wherein two of the plurality of impellers rotate in opposite directions. 
     
     
         29 . The GPS of  claim 25 , wherein the enclosure is ring-shaped. 
     
     
         30 . The GPS of  claim 25 , wherein the enclosure defines a volume of less than about one liter. 
     
     
         31 . The GPS of  claim 25 , wherein the impeller comprises a plurality of holes in its outer rim. 
     
     
         32 . The GPS or  claim 25 , wherein the GPS comprises a ring-shaped impeller, the ring-shaped impeller laterally surrounding and adapted to rotate around one or more other elements. 
     
     
         33 . The GPS of  claim 32 , wherein the ring-shaped impeller laterally surrounds and is adapted to rotate around a stage adapted to hold a substrate.