The NanoImprint Lithography (NIL) technology by using a soft stamp is today ready for high volume manufacturing (HVM) with the global solution proposed by EVG1. This UV-based imprint, using a transparent stamp is now a standard technology and the most common option for the full wafer imprint, meaning the size of the stamp correspond to the size of the wafer to print. Previous work has shown promising results with strong repeatability and uniformity in terms of critical dimension (CD)2. In 2017, larges features, bigger than 500 nm period, and shallow aspect ratio were qualified3. Latter in 20194, lithography and etching through a Si/SiO2 stack were demonstrated for 25 wafers imprinted in a single run:
- Depending on several diameters contact (from 100 to 50 nm) and densities (from 1:3 to 1:15).
- For line and space arrays with a density of 1:4 and variable spaces widths (from 100 to 50 nm).
In this paper we demonstrate that the limit of the patterns dimension can be pushed to sub-50 nm features thanks to EVG SmartNIL technology, the optimized EVGNIL-UV/AS2 soft stamp material with matching resist as well as the improvement of pattern transfer by dry etching. Based on CDSEM metrology, and SEM cross-sections, high fidelity and reproducibility were demonstrated, with 25 replications in a single run using the same soft stamp. Transfer compatibility of the imprint material was validated until 45 nm line, with 1:4 density. Furthermore, the process window of this NIL technology and its compatibility with applications as photonics and 3D patterning are discussed. The specific developments achieved around stripping of the substrates and the perspectives for low defectivity process are pointed out.