RF plasma-enhanced deposition of fluorinated films

Abstract

Low- or atmospheric pressure RF plasma-enhanced thin film deposition methods are provided for the deposition of hydrophobic fluorinated thin films onto various substrates. The methods include at least two steps. In the first step, RF plasma-mediated deposition is used to deposit a fluorinated film onto a substrate surface. In a second step, plasma-generated active sites on the fluorinated film are quenched by reacting them with stable fluorinated gas-phase molecules in situ, in the absence of plasma, to provide a hydrophobic fluorinated thin film having a very low oxygen content. In some instances the hydrophobic fluorinated thin films have an atomic oxygen concentration of no more than about 3%.

1 . A method for forming a fluorinated film on a surface, the method comprising: 
 (a) depositing a fluorinated film comprising active sites on the surface by exposing the surface to an RF plasma comprising fluorine-containing molecular fragments generated from fluorinated precursor molecules; and    (b) quenching the active sites by exposing the fluorinated film to a gas comprising fluorinated quenching molecules in situ, in the absence of plasma.    
   
   
       2 . The method of  claim 1 , wherein the precursor molecules comprise hexafluoropropylene molecules.  
   
   
       3 . The method of  claim 1 , wherein the precursor molecules comprise hexafluoropropylene oxide molecules.  
   
   
       4 . The method of  claim 1 , wherein the fluorinated quenching molecules comprise hexafluoropropylene molecules.  
   
   
       5 . The method of  claim 1 , wherein the fluorinated quenching molecules comprise hexafluorpropylene oxide molecules.  
   
   
       6 . The method of  claim 1 , wherein the fluorinated precursor molecules and the fluorinated quenching molecules are independently selected from the group consisting of hexafluoropropylene molecules and hexafluoropropylene oxide molecules.  
   
   
       7 . The method of  claim 1 , wherein the fluorinated film comprises at least about 55 atomic percent fluorine.  
   
   
       8 . The method of  claim 7 , wherein the fluorinated film comprises no more than about 3 atomic percent oxygen.  
   
   
       9 . The method of  claim 1 , wherein a water contact angle on the fluorinated film is at least about 110 degrees.  
   
   
       10 . The method of  claim 8 , wherein a water contact angle on the fluorinated film is at least about 110 degrees.  
   
   
       11 . The method of  claim 1 , wherein the C/F ratio of the fluorinated film is at least 0.7.  
   
   
       12 . The method of  claim 1 , wherein the surface is the surface of a medical device.  
   
   
       13 . The method of  claim 12 , wherein the medical device is a catheter guide wire.  
   
   
       14 . The method of  claim 1 , wherein the surface comprises a metal, a glass or a polymer.  
   
   
       15 . A coated substrate comprising: 
 (a) a substrate having a surface; and    (b) a crosslinked fluorinated film bonded the surface of the substrate;    wherein the fluorinated film has a fluorine content of at least about 50 atomic percent, an oxygen content of no more than about 3 atomic percent and a C/F ratio of about 0.7 to about 1.    
   
   
       16 . The coated substrate of  claim 15 , wherein the fluorinated film has a water contact angle of at least about 110 degrees.  
   
   
       17 . The coated substrate of  claim 15 , wherein the substrate is a medical device.  
   
   
       18 . The coated substrate of  claim 17 , wherein the medical device is a catheter guide wire.  
   
   
       19 . The coated substrate of  claim 15 , further comprising biomolecules attached to the fluorinated film.  
   
   
       20 . A coated substrate comprising: 
 (a) an inorganic substrate having a surface; and    (b) a crosslinked fluorinated film bonded to the surface of the substrate;    wherein the fluorinated film has a fluorine content of at least about 50 atomic percent and an oxygen content of no more than about 3 atomic percent.    
   
   
       21 . The coated substrate of  claim 20 , wherein the fluorinated film has a fluorine content of at least 60 atomic percent and an oxygen content of no more than about 2 atomic percent.  
   
   
       22 . The coated substrate of  claim 20 , wherein the inorganic substrate comprises a metal substrate.  
   
   
       23 . The coated substrate of  claim 22 , wherein the metal substrate comprises a stainless steel substrate.  
   
   
       24 . The coated substrate of  claim 20 , wherein the inorganic substrate comprises a silica substrate or a glass substrate.  
   
   
       25 . The coated substrate of  claim 20 , wherein the substrate is a medical device or medical implant.  
   
   
       26 . The coated substrate of  claim 20 , wherein the substrate is a catheter guide wire.  
   
   
       27 . The coated substrate of  claim 20 , further comprising biomolecules attached to the fluorinated film.