MuGFET observation and CD measurement by using CD-SEM

Multiple Gate Field Effect Transistors (MuGFETs) have been proposed to enable downsizing, when scaling the transistors to the 32nm technology node. The dimension of the gate on the surface of fin determines the effective channel length of the device. So, the characterization of the gate profiles at fin sidewalls becomes extremely critical. It is especially important to quantify the rounded intersection (etch residual) at the intersection of the fin and gate. In this report, we show top down images of a MuGFET taken with critical-dimension scanning electron microscopy (CD-SEM) and the results that were measured and characterized by measuring various portions of the pattern which will impact the MuGFET performance i.e. gate length, fin width. We will introduce a quantified relation between fin length and "its effect on the etch residue at the intersection of fin and gate". Next we discuss our approaches to analyze the variation of the shape of the gate at the fin sidewall.