Porous photoresist stamps for selective plasma treatment

A porous plasma stamp has been developed allowing selective plasma treatment and coating of flat surfaces by using a dielectric barrier discharge arrangement at atmospheric pressure. The stamp consists of a porous sinter metal plate covered with photoresist. The photoresist is structured to form cavities in which the plasma is burning. The cavity footprint is the desired structure to be reproduced or "plasma printed" on the substrate. It is shown that flat substrate surfaces can be treated in the same scale as the cavity dimensions and that the treated areas are defined by the footprint of the cavities with a precision in micrometer scale. This work describes in detail the manufacturing process of the plasma stamp and furthermore shows that the stamp can be used to plasma-coat surfaces selectively because the stamp cavities can continuously be filled with process gases through the porous metal plate. Applying process gas containing polymerizable monomers to a porous material will close the pores after a certain plasma treatment time. As a consequence this work also addresses the issue of cleaning the stamp to keep it intact for a long term usage.