Precision surface treatments using dense fluids and a plasma

Abstract

The present invention is a method, process and apparatus for selective cleaning, drying, and modifying substrate surfaces and depositing thin films thereon using a dense phase gas solvent and admixtures within a first created supercritical fluid antisolvent. Dense fluids are used in combination with sub-atmospheric, atmospheric and super-atmospheric plasma adjuncts (cold and thermal plasmas) to enhance substrate surface cleaning, modification, precision drying and deposition processes herein. Moreover, conventional wet cleaning agents such as hydrofluoric acid and ammonium fluoride may be used with the present invention to perform substrate pre-treatments prior to precision drying and cleaning treatments described herein. Finally, dense fluid such as solid phase carbon dioxide and argon may be used as a follow-on treatment or in combination with plasmas to further treat a substrate surface.

I claim:  
     
         1 . A method for treating a portion of substrate surface comprising the steps of: 
 (a) placing a substrate having a surface to be treated in a pressure vessel;    (b) introducing a supercritical anti-solvent into the pressure vessel and establishing a first supercritical fluid anti solvent phase in contact with the substrate, the anti-solvent phase having a pressure and temperature above the critical points of the anti-solvent;    (c) introducing a supercritical solvent into the pressure vessel and contacting a portion of the substrate surface to be treated within the pressure vessel; then    (d) altering the physiochemistry of the dense fluid solvent to create a treating phase in contact with the portion of the substrate surface to be treated;    (e) then removing the treating phase, from the pressure vessel.    
     
     
         2 . The method in accordance with  claim 1  wherein the supercritical anti-solvent is supercritical nitrogen, supercritical argon, supercritical oxygen, supercritical xenon, supercritical helium or mixtures thereof and the supercritical solvent is supercritical carbon dioxide, supercritical nitrous oxide, a supercritical hydrocarbon or mixtures thereof.  
     
     
         3 . The method on accordance with  claim 1  further comprising energizing an electrode positioned in the pressure vessel at a predetermined distance from the substrate at a voltage between 500 volts and 250,000 volts and at a frequency between 100 KHz and 10 GHz and a power of between 50 and 5000 watts.