(Invited) Patterning Process Model Challenges for 14 Nm

Abstract

The taxonomy of semiconductor technology nodes has long since decoupled from the minimum critical dimension (CD) associated with the designs, but each new node nonetheless features a variety of difficult challenges. CD control and placement budgets continue to tighten with each node as new and more complex RET strategies such as multi-layer patterning, model-based assist feature, pixelated illumination sources, and negative tone develop processes are deployed. Optical Proximity Correction (OPC) is of course a vital enabler for advanced manufacturing, and OPC models describe the entire patterning process, including photomask, optics, resist, and etch as a set of separate modules. There are many factors which impact the accuracy and predictive power of these semi-empirical photomask, optical, and resist models, and care must be taken to ensure appropriate representation of all physical system parameters. These include mask critical dimension (XY) and optical (Z) properties, since 3DEMF effects are important at 14 nm node dimensions. In addition to single plane CD prediction, models must be aware of various three dimensional patterning failure modes such as SRAF printing, resist toploss, and resist pattern collapse. This paper will review the critical challenges for patterning process models for the 14 nm node.