(24b) Surface Reaction Kinetics during Area-Selective Thin Film Deposition

Advances in chemical reaction engineering impact chemical manufacturing, but also play an important role in manufacturing of advanced semiconductor devices. Chemical processes used for semiconductors, including lithographic patterning, thin film atomic layer deposition (ALD) and atomic layer etching (ALE), are among the most precise chemical methods used in any large-scale manufacturing enterprise. Even so, new problems are arising that demand better control, precision and flexibility of deposition and etching. A key challenge is the ability to achieve desired atomic structure and bonding while maintaining low process temperature, often less than 200°C. Compared to high temperature processes where thermodynamic equilibrium can be attained, controlling reactions at low temperature generally requires better control and adjustment of surface reaction kinetics.

This presentation will discuss the role of reaction kinetic mechanisms in controlling thin film nucleation and area-selective deposition (ASD) for applications in electronic materials nanoscale patterning. For example, reaction rates during ALD can be independent of temperature, whereas the extent of material removed during ALE is generally temperature dependent. ASD often proceeds by combining ALD and ALE reactions, so understanding these
rate processes is instrumental in process design. Moreover, the balance between deposition and etching rates can lead to some unexpected results when deposition and etching are applied as an “intensified” process, either in parallel or sequentially, to patterned substrates. John Ekerdt’s substantial contributions to reaction rate mechanisms for electronic materials have influenced our group’s thinking and understanding, and we are happy to participate in this special session in his honor.