Simple masking method for selective atomic layer deposition of thin films

Abstract

A simple physical masking method is presented for selective atomic layer deposition (ALD). Iron powder and a magnet are used as a masking pair. This method is easy and efficient for depositing patterned thin films with feature sizes estimated 0.3 mm or larger on any substrate. In this work, using iron powder held in place by a magnet would mask part of the silicon wafer substrate, while no iron powder is on the unmasked part. A silver particulated thin film was deposited on the masked Si wafer. X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy were used for silver characterization on the masked and unmasked parts of the sample. Results indicated that an ALD-like surface growth of a silver thin film occurred on the unmasked Si wafer, and no growth was detected on the masked portion of the Si wafer.

Is atomic layer deposition of silver possible on N95 masks?

“…Ag(fod)(Pet3) (Ag(C3F7COCHCOC4H9)P(CH2CH3)3, CAS #165461-74-5) from Strem Chemicals Inc. was used as the silver precursor and it was maintained at 96 °C during all depositions. Borane dimethylamine complex ((CH3)2NH•BH3, CAS #74-94-2) from Sigma Aldrich was used as a reducing agent/co-reactant to react with Ag(fod)(Pet3) and depositmetallic silver on the substrate [25] , [26] , [27] . The borane bubbler was kept at 52 °C.…”