Editor-in-Chief Harry Levinson gives an overview of mask-centric conferences.

In extreme ultraviolet lithography, multilayer roughness effects are a key contributor to mask-induced pattern roughness. Replicated roughness from the mask substrate results in a spatially dependent phase error that ultimately manifests as aerial image roughness at the wafer. While previous studies have examined the impact of multilayer roughness on line/space patterns, the impact on 2D patterns, i.e., contacts and vias, has not been thoroughly examined. We investigate the impact of multilayer roughness on contact hole patterns for both tantalum and ruthenium absorber materials. We observe that multilayer roughness, and in particular the resulting phase curvature, gives rise to local shifts in best focus consistent with experimentally observed phenomena.

As the resource-intensive semiconductor industry progresses, concerns about environmental sustainability are intensifying, and efforts to achieve sustainable chip manufacturing are accelerating. As the complexity of process steps and nodes increases significantly to achieve narrower pitches, the lithography process, which consumes a substantial amount of power, has emerged as a critical issue in terms of electrical energy consumption. We propose a novel process that substantially reduces electricity consumption as a feasible alternative to the conventional thermal crosslinking approach. We provide a comprehensive discussion of an optical crosslinking system designed to crosslink underlayer materials, such as spin-on carbon and spin-on glass, solely through light exposure, thereby eliminating the need for heat. By replacing the traditional thermal baking system, which is energy-intensive, with the energy-efficient optical crosslinking system, we demonstrate the potential to save both energy and processing time on the track without compromising lithographic performance. To validate the feasibility of the proposed approach and materials, we conducted film crosslinking confirmation and etch rate tests using light-curable underlayer materials. Subsequently, we analyzed and evaluated the performance of pitch 28 nm line/space patterning under optimized curing conditions. The patterning tests with light-curable underlayers yielded competitive results compared with those with the thermal underlayer. The introduction of the innovative optical crosslinking system can contribute to harmonizing environmental sustainability with the semiconductor industry, providing ecological benefits and facilitating sustainable semiconductor manufacturing.

Pattern collapse emerges as a key factor leading to the failure of photoresist patterns in high-resolution extreme ultraviolet lithography (EUVL). Its significance escalates as feature sizes decrease and pitches become smaller, transitioning to high-numerical aperture extreme ultraviolet, potentially leading to challenges with regard to resolution. Pattern collapse arises from capillary forces acting on the resist surface during wafer drying. Consequently, the optimal strategy to mitigate pattern collapse involves eliminating any drying steps post-lithography processing. We introduce the organic dry development rinse (O-DDR) process for spin-on metal oxide resist, effectively eliminating capillary force and eradicating the pattern collapse issue without tone inversion. This involves dispensing O-DDR material instead of employing a spin-drying developer, without introducing any extra processing steps. After the dry etching process, we observe that the resist patterns, such as pitch 32-nm pillars and pitch 28-nm line and space, appear to have mostly no collapse at small pitches or low doses. Furthermore, we analyze the O-DDR process, intending to expand the window for a failure-free process with pitch 32-nm pillars and pitch 28-nm line and space in EUVL.