The development of new resist materials
is vital to fabrication
techniques for next-generation microelectronics. Inorganic resists
are promising candidates because they have higher etch resistance,
are more impervious to pattern collapse, and are more absorbing of
extreme ultraviolet (EUV) radiation than organic resists. However,
there is limited understanding about how they behave under irradiation.
In this work, a Hf-based hybrid thin film resist, known as “hafnicone”,
is deposited from the vapor-phase via molecular layer deposition (MLD),
and its electron-beam and deep-ultraviolet (DUV)-induced patterning
mechanism is explored. The hafnicone thin films are deposited at 100
°C by using the Hf precursor tetrakis(dimethylamido)hafnium(IV)
and the organic precursor ethylene glycol. E-beam lithography, scanning
electron microscopy, and profilometry are used to investigate the
resist performance of hafnicone. With 3 M HCl as the developer, hafnicone
behaves as a negative tone resist which exhibits a sensitivity of
400 μC/cm2 and the ability to resolve 50 nm line
widths. The resist is characterized via X-ray photoelectron spectroscopy
(XPS) and infrared spectroscopy (IR) to investigate the patterning
mechanism, which is described in the context of classical nucleation
theory. This study of hafnicone hybrid MLD demonstrates the ability
for the bottom-up vapor deposition of inorganic resists to be utilized
in advanced e-beam and DUV lithographic techniques.