CD-based process windows have been an analysis workhorse for estimating and comparing the robustness of semiconductor microlithography processes for more than 30 years. While tolerances for variation of CD are decreasing in step with the target CD size, the acceptable number of printed defects has remained flat (Hint: Zero) as the number of features increases quadratically. This disconnect between two key process estimators, CD variability and defect rate, must be addressed. At nodes that require EUV lithography, estimating the printed defects based solely on a Mean CD (“Critical Dimension”) process window is no longer predictive. The variability / distribution of the printed CDs must be engineered so that there are no failures amongst the billions of instances, rendering the Mean CD, often measured on just hundreds or thousands of instances, a poor predictor for outliers. A “defect-aware” process window, where the count of printed defects is considered in combination with more advanced statistical analysis of measured CD distributions can provide the needed predictability to determine whether a process is capable of sufficient robustness. Determining process robustness where stochastics and defects are taken into account can be simplified by determining the CD process margin. In this work we study dense contact hole arrays exposed with 0.33NA single exposure EUV lithography after both the lithography and etch steps. We describe a methodology for expanding the analysis of process windows to include more than the mean and 3σ of the data. We consider the skew and kurtosis of the distribution of measured CD results per focus-exposure condition and compare / correlate the measured CD process window results to the CD process margin.
Directed self-assembly (DSA) has been investigated over the past few years as the candidate for next generation lithography. Especially, sub 20nm line and space patterns obtained by chemo-epitaxy process are expected to apply to DRAM active area, Logic fin and narrow metal patterns. One of the biggest advantages of DSA lines is that the pattern pitch is decided by the specific factors of the block copolymer, and it indeed the small pitch walking as a consequence. However, the generating mechanism of the DSA pattern defect is still not cleared<sup>1-4</sup> and the line edge roughness (LER) is not overtaken self- aligned quadruple patterning (SAQP). <p> </p>In this report, we present the latest results regarding the defect reduction and LER improvement work regarding chemoepitaxy line and space pattern. In addition, we introduce the result of application of chemical epitaxy process to hole pattern.