A study was conducted, to present and test the gas-phase soft lithography methodology for direct patterning of silicon substrates at the micrometer and nanometer scale. It was demonstrated that the methodology belonged to the soft-lithography class, as it uses a polymeric impression for replicating the features of the original substrate. The methodology involved pouring of a poly(dimethylsiloxane) (PDMS) prepolymer onto the original substrate, where it adopted the shape of the original features. The PDMS mold was removed and placed in a reaction chamber, containing a silane saturated atmosphere, after curing. It was found that PDMS loads up with the volatile molecules, due to its characteristic permeability to gases. It was also found that PDMS adhesion results in the formation of cavities with the shape of the original features, transferring gas-phase molecules by diffusion and react with the exposed surface.
- Gas-phase reactions
- Soft lithography