Electrochemical Atomic Layer Deposition and Etching – Enabling Technologies for Atomically-Precise Fabrication of High-Performance Interconnects

Moore’s law drives miniaturization of transistors and interconnects in nano-electronics circuits. As critical interconnect dimensions approach the 1 nm length scale, the semiconductor industry will need revolutionary advances in: (i) novel materials and integrated approaches to fabricate interconnects with lower resistance; and (ii) processing technologies for atomically-precise fabrication of novel materials and structures. In the present talk, we will outline the fundamental aspects of electrochemical atomic layer deposition (e-ALD) and etching (e-ALE) processes that enable atomically-precise fabrication of advanced interconnects. We will highlight the key uniqueness of our e-ALD approach, namely the utilization of underpotentially-deposited Zn adlayers to facilitate e-ALD of metals. This uniqueness extends considerably the range of materials accessible via e-ALD to include emerging interconnect materials beyond Cu, i.e., Pt-group metals, non-noble metals such as Co and its alloys, as well as non-metals. Furthermore, our e-ALD approach enables fabrication of novel Zn-silicate based self-forming barriers, which allow for integrated dual-damascene fabrication approaches with significant reductions in interconnect resistance. Void-free metallization of sub-10 nm features utilizing e-ALD will be demonstrated. Finally, efforts to build a library of materials accessible via e-ALD and its etching analog (e-ALE) will be described, and recent progress in building a multi-scale predictive e-ALD process model will be discussed.