Touchless Site Isolation Using Gas Bearing

Abstract

A gas bearing seal using porous materials for distribution of gas flow can provide site isolation during wet processing. In some embodiments, a flow cell comprises a porous media gas bearing surrounding a periphery of the flow cell, isolating the liquid inside the flow cell from the ambient air outside the flow cell. In some embodiments, a protective chuck comprises a porous media gas bearing disposed in a middle of the protective chuck, isolating the liquid outside the protective chuck with the gaseous ambient generated by the porous media gas bearing.

What is claimed is: 
     
         1 . A substrate processing system comprising:
 a flow cell, the flow cell comprising:
 a hollow interior operable to receive a fluid; 
 a peripheral portion circumscribing the hollow interior and comprising a bottom surface; 
 a porous medium disposed at the bottom surface of the peripheral portion such that the porous medium circumscribes the hollow interior; and 
 an inlet in fluid communication with the peripheral portion such that when gas is flowed into the peripheral portion through the inlet, the gas exits the bottom surface of the peripheral portion through the porous medium and is operable to confine a fluid disposed in the hollow interior of the flow cell from spreading from a first surface region of a substrate to a second surface region of the substrate when the bottom surface of the peripheral portion is disposed in proximity to the first surface region of the substrate. 
   
     
     
         2 . The substrate processing system of  claim 1 , wherein the flow cell further comprises a fluid conduit in fluid communication with the hollow interior. 
     
     
         3 . The substrate processing system of  claim 2 , wherein the flow cell further comprises an isolation wall extending from an upper portion of the flow cell into the hollow interior, wherein the isolation wall is spaced apart from an interior wall of the hollow interior such that bubbles formed at an interface between the gas flowing from the bottom surface of the peripheral portion and the fluid in the hollow interior are confined between the isolation wall and the interior wall of the hollow interior. 
     
     
         4 . The substrate processing system of  claim 1 , further comprising a mechanism operable to levitate the flow cell above the first surface region through magnetic levitation. 
     
     
         5 . The substrate processing system of  claim 1 , further comprising a flow controller in fluid communication with the inlet of the flow cell. 
     
     
         6 . The substrate processing system of  claim 1 , wherein the flow cell further comprises a stirrer disposed within the hollow interior and operable to stir the fluid disposed in the hollow interior of the flow cell. 
     
     
         7 . The substrate processing system of  claim 1 , further comprising a pressure gauge operable to measure a pressure of the gas exiting the bottom surface of the peripheral portion of the flow cell through the porous medium. 
     
     
         8 . The substrate processing system of  claim 1 , further comprising a restricting valve coupled to the inlet of the flow cell. 
     
     
         9 . The substrate processing system of  claim 3 , wherein the isolation wall is a solid wall. 
     
     
         10 . The substrate processing system of  claim 3 , wherein the isolation wall is a perforated wall. 
     
     
         11 . A substrate processing system comprising:
 a flow cell, the flow cell comprising:
 a hollow interior operable to receive a fluid; 
 a peripheral portion circumscribing the hollow interior and comprising a bottom surface; 
 a porous medium disposed at the bottom surface of the peripheral portion such that the porous medium circumscribes the hollow interior; and 
 an inlet in fluid communication with the peripheral portion such that when gas is flowed into the peripheral portion through the inlet, the gas exits the bottom surface of the peripheral portion through the porous medium and is operable to confine a fluid disposed in the hollow interior of the flow cell from spreading from a first surface region of a substrate to a second surface region of the substrate when the bottom surface of the peripheral portion is disposed in proximity to the first surface region of the substrate, 
 wherein the flow cell further comprises an isolation wall extending from an upper portion of the flow cell into the hollow interior, wherein the isolation wall is spaced apart from an interior wall of the hollow interior such that bubbles formed at an interface between the gas flowing from the bottom surface of the peripheral portion and the fluid in the hollow interior are confined between the isolation wall and the interior wall of the hollow interior. 
   
     
     
         12 . The substrate processing system of  claim 11 , wherein the flow cell further comprises a stirrer disposed within the hollow interior and operable to stir the fluid disposed in the hollow interior of the flow cell. 
     
     
         13 . The substrate processing system of  claim 12 , further comprising a mechanism operable to levitate the flow cell above the first surface region through magnetic levitation. 
     
     
         14 . The substrate processing system of  claim 13 , further comprising a pressure gauge operable to measure a pressure of the gas exiting the bottom surface of the peripheral portion of the flow cell through the porous medium. 
     
     
         15 . The substrate processing system of  claim 14 , further comprising a flow controller in fluid communication with the inlet of the flow cell. 
     
     
         16 . A substrate processing system comprising:
 a plurality of flow cells, each of the plurality of flow cells comprising:
 a hollow interior operable to receive a fluid; 
 a peripheral portion circumscribing the hollow interior and comprising a bottom surface; 
 a porous medium disposed at the bottom surface of the peripheral portion such that the porous medium circumscribes the hollow interior; and 
 an inlet in fluid communication with the peripheral portion such that when gas is flowed into the peripheral portion through the inlet, the gas exits the bottom surface of the peripheral portion through the porous medium and is operable to confine a fluid disposed in the hollow interior of the flow cell from spreading from a first surface region of a substrate to a second surface region of the substrate when the bottom surface of the peripheral portion is disposed in proximity to the first surface region of the substrate. 
   
     
     
         17 . The substrate processing system of  claim 16 , wherein each of the plurality of flow cells further comprises an isolation wall extending from an upper portion of the flow cell into the hollow interior, wherein the isolation wall is spaced apart from an interior wall of the hollow interior such that bubbles formed at an interface between the gas flowing from the bottom surface of the peripheral portion and the fluid in the hollow interior are confined between the isolation wall and the interior wall of the hollow interior. 
     
     
         18 . The substrate processing system of  claim 17 , wherein the isolation wall within each of the plurality of flow cells is a perforated wall. 
     
     
         19 . The substrate processing system of  claim 18 , wherein each of the plurality of flow cells further comprises a stirrer disposed within the hollow interior and operable to stir the fluid disposed in the hollow interior of the flow cell. 
     
     
         20 . The substrate processing system of  claim 19 , further comprising at least one mechanism operable to levitate each of the plurality of flow cells above the surface of the substrate through magnetic levitation.