Atomic scale control in fabrication steps for advanced logic and memory manufacture is critical not only for manufacturing viability of widely disparate structures but also functionality of complex devices. Different approaches ranging from the use of “tighter” process control options to leveraging self-limiting cyclic processing have been explored to achieve atomic scale control utilizing seemingly unwieldy plasmas. Process technology is married to plasma as the most capable methods of delivering area selective etch or low temperature selective deposition. A hindrance for advancing the control of plasma modified surfaces is that plasmas modify surfaces resulting in non-ideal states. Current process engineering can accommodate less-than-ideal surfaces; however, even in the best case, managing non-idealities introduces significant complexity. The use of first principles in-situ diagnostics and simulation together provides a path towards increased understanding of plasma-surface interactions and atomic scale control of the surface and sub-surface. Physisorption-mediated plasma processes are useful to illustrate the combination of quantum chemistry and in-situ diagnostics as the etch precursor is delivered to the surface in an unfragmented state. The presentation will include examples of how this system can be used to gain an understanding of the sensitivity of processes to different types of surfaces. It will conclude with forward looking content related to the de-cluttering of plasma processes using new learning concepts.