20-NM LINEWIDTH PLATINUM PATTERN FABRICATION USING CONFORMAL EFFUSIVE-SOURCE MOLECULAR PRECURSOR DEPOSITION AND SIDEWALL LITHOGRAPHY

In a manner suitable for large-scale processing, vertical platinum structures having thicknesses (linewidths) down to 20 nm, heights up to 700 nm, an aspect ratio up to 13, and different geometric shapes have been fabricated on top of a silicon dioxide substrate by Pt deposition from the thermal decomposition of a platinum precursor molecule under gas phase collisionless conditions followed by ion-assisted etching. Scanning electron microscopy analysis shows that the structures have very small grains, high uniformity, and very sharp contours, demonstrating a high degree of conformal deposition. Scanning Auger microscopy reveals platinum only on the structures. X-ray diffraction and x-ray photoelectron spectroscopy analysis of the as-deposited platinum film show that the platinum film is polycrystalline and has no detectable impurity. Scotch tape test shows good bonding of the film. Mass spectrometric measurements suggest that substantial amounts of stable precursor fragments from partial decomposition of the parent precursor desorb from the substrate. The observed desirable film morphology and purity can be attributed to the favorable choice of template material, decomposition mechanism of the precursor, and the chemical beam conditions used.