Nanoimprint Lithography appears to be a competitive candidate for Next Generation Lithography in semiconductor
industry due to its advantages concerning resolution and cost effectiveness. Moreover, UV-Nanoimprint Lithography
(UV-NIL) should enable to reach good overlay values, which is also a major criterion for integration.
In this paper, we present first integration results which were obtained on lines and contact holes. A specific template was
designed for this purpose in collaboration with CEA-LETI, IMS and Molecular Imprints. This template was
characterized by using various techniques (optical and SEM techniques) and showed quite a good quality of the
template; in particular, 50 nm holes were defined.
Molecular Imprints process was then tested by using Imprio55® at MESA+ Research Institute, University of Twente
(Netherlands). In these experiments, 37 4.8 cm2 fields were imprinted on Double Side Polished wafers. For each field, 52
droplets were dispensed with various volumes. Resolution and non-uniformity were evaluated after imprinting. Then
etching tests were performed.
When projected with a scanner, the latent image intensity in the photoresist has a slope that can be much lower than
with an interferometer. To study finely the lithographic process and to be predictive, the Normalized image slope of 193
nm immersion interferometer built at LETI has to be controlled. The exposure latitude (EL), the Normalized Image Log
Slope (NILS) and the interference contrast are closely related.
Extreme Ultraviolet (EUV) masks are composed of EUV-reflective regions (multilayer) and of EUV-absorbing regions (patterned areas). The choice of materials for the absorbing stack (i.e. the buffer layer and the absorber layer) is crucial for providing good optical performances. This choice has to take into account three major issues: optical aspects (EUV and DUV performances, aerial image); repair feasibility and technological feasibility (deposition, etching, stripping...); ageing and utilization aspects: stability of the stack, cleaning capability. In this paper, a new absorbing stack A/B is proposed: this stack completely fulfils optical specifications and its total thickness is much lower than those found in the literature, with absorbing materials like TiN, Cr or TaN for instance. This thin thickness enables to reduce shadowing effects, which is particularly interesting for very advanced nodes. Experimental studies were then carried out on this new stack. We focused on two major topics: low temperature deposition and wet etching feasibility of B-material.