(Invited) Atomic Level Precision in Near-Zero Thickness Thin Film Deposition Through Chemistry and Process Innovation

Abstract

The semiconductor industry is being radically impacted by placing greater emphasis on the development of hetero-devices and systems that will act as essential drivers for a wide spectrum of technological applications across multiple industrial sectors. The introduction of new materials and their integration with currently used materials are projected to replace IC design and device scaling as the key enablers to the realization of improved device performance and larger density gains. Yet material selection has been constrained by existing fabrication process technology. To date, fabrication processes have dictated material selection by limiting chemical sources or precursors to those that match existing process tools associated with CVD and ALD and their variants, which in turn limits material compositions in ICs. The processing and integration of new materials structures will require the introduction of new deposition and etching processes, and manufacturing worthy protocols that provide new methods for atomic level control.This presentation explores four new such processes and protocols that match these requirements, namely: P-CVD SiNx: This process combines precursor thermal adsorption with the reaction with remote plasma ammonia. A demonstration is presented in which thermal adsorption of tri(isopropyl)cyclotrisilazane (TICZ) ensures a substrate driven nucleation and growth process that leads ultimately to conformal SiNx in extremely high aspect ratio structures. Concurrently, the application of a remote NH3 plasma eliminates any undesirable plasma-induced effects on the substrate and growing film. Single Pulse CVD/ALD: These are methods for pulsed deposition of thin films that offer significant reduction in the time to generate thin films by eliminating a number of the steps required in growth cycles. In the case of ALD, for instance, it reduces the number of steps required to grow every individual thin film layer from four to one, thus maximizing process efficiency and wafer throughput, and leading to competitive manufacturing cost of ownership and return on investment. The deposition of high quality cobalt films from cobalt tricarbonyl nitrosyl will be discussed in this context. Vapor Phase Transient Species Deposition. The discrete generation of transient species under conditions distinct from the substrate and the parent precursor will be discussed. This process enables the deposition of films in lower thermal or energetic substrate environments. It also enables the deposition of films at lower temperatures and ensures greater conformality of the deposited films, allowing film deposition on thermally or chemically fragile substrates. Integrated Synthesis and Deposition (ISD): A manufacturing paradigm comprising a method and system for real-time, closed-loop synthesis, supply, and consumption of precursors in IC manufacturing processes. In its simplest form, the system consists of a precursor synthesis chamber being physically interfaced with a thin film processing chamber, with precursor being synthesized on demand and supplied in a controlled fashion into the thin film processing chamber where it is consumed in the manufacturing process. This allows practical methods to employ highly reactive chemistry that otherwise could lead to explosive or highly toxic releases.