Plasma-Enhanced Atomic Layer Deposition of Boron Carbide for Interconnect Applications
Abstract
As the semiconductor industry endeavors to scale integrated circuit dimensions—
decreasing layer thicknesses while increasing the aspect ratio of fillable features—the
need for novel interconnect materials with highly specialized properties continues to rise.
Meeting the requirements for the numerous types of materials needed, including low-k
dielectrics, etch stops, metal diffusion barriers, hardmasks, spacer layers, and other
pattern-assist layers, with traditional silicon-based materials is becoming increasingly
challenging. As an alternative to silicon, amorphous hydrogenated boron carbide (aBC:H), grown through plasma-enhanced chemical vapor deposition (PECVD), has been
demonstrated to possess excellent dielectric properties, combined with very high Young’s
modulus, electrical properties rivaling those of SiOC:H variants, very good chemical
stability, and unique and useful etch chemistry. However, a problem with PECVD growth
that will limit its long-term utility is its inability to scale while maintaining uniform,
conformal coatings for very thin films.
To combat the issues arising from PECVD grown boron carbide, a plasmaenhanced molecular-layer-deposition-based process for the growth of BC films on metal
(copper) substrates using solid carborane precursors was proposed. This thesis describes
the design and construction of a reactor chamber capable of this hypothesized film
growth as well as the characterization of those preliminary depositions. Monolayer
carborane growths on copper substrates were demonstrated with characterization
including in situ spectroscopic ellipsometry, as well as ex situ contact angle analysis and
X-ray photoelectron spectroscopy. The surface of the monolayer was then plasma treated
and preliminary multi-layer growths were tested
Table of Contents
Background -- Experimental -- Results & Discussion -- Conclusion and Future Work
Degree
M.S. (Master of Science)