Photobase Generator Enabled Pitch Division: A Progress Report

Pitch division lithography (PDL) with a photobase generator (PBG) allows printing of grating images with twice the pitch of a mask. The proof-of-concept has been published in the previous paper[1, 2] and demonstrated by others[1]. Forty five nm half-pitch (HP) patterns were produced using a 90nm HP mask, but the image had line edge roughness (LER) that does not meet requirements. Efforts have been made to understand and improve the LER in this process. Challenges were summarized toward low LER and good performing pitch division. Simulations and analysis showed the necessity for an optical image that is uniform in the z direction in order for pitch division to be successful. Two-stage PBGs were designed for enhancement of resist chemical contrast. New pitch division resists with polymer-bound PAGs and PBGs, and various PBGs were tested. This paper focuses on analysis of the LER problems and efforts to improve patterning performance in pitch division lithography.Chemical Engineerin

Fluorinated Polymethacrylates as Highly Sensitive Non-chemically Amplified E-beam Resists

In an effort to improve upon the sensitivity of commercial non-chemically amplified e-beam resists, four polyacrylates functionalized with alpha-CF3 and/or CH2CF3 alkoxy substituents were studied. The alpha-CF3 substituent is known to increase backbone-scission efficiency while simultaneously eliminating acidic out-gassing and cross-linking known to occur in alpha-halogen substituted polyacrylates. Contrast curves for the polymeric alpha-CF3 acrylates, generated through e-beam exposure, showed the resists required an order of magnitude less dose than the current industry-standards, PMMA and ZEP. The fundamental sensitivity of these materials to backbone scissioning was determined via Co-60 gamma-ray irradiation. The chain scissioning, G(s), and cross-linking, G(x), values calculated from the resulting change in molecular weight demonstrated that all fluorinated resists possess higher G(s) values than either PMMA or ZEP and have no detectable G(x) values. Utilizing e-beam and EUV interference lithographies, the photospeed of PMTFMA was found to be 2.8x and 4.0x faster, respectively, than PMMA.Chemistr

Transition Experiments for Circular Construction: Learning-by-doing, but how?: A typology for transition learning in circular building experiments

In order to mitigate the high environmental impact of the construction sector, the Dutch government envisions a fully circular building economy by 2050. The first phase of this transition (2018-2023) consists of experimentation. Here, circular building experiments should trigger radically new ways of thinking and radically new ways of doing. Learning-by-doing is the device, but clear conceptual knowledge on how to achieve deep learning is lacking. Therefore, this explorative research aims to assess how circular building experiments could be designed in order to stimulate deep learning. Stakeholders involved in the design and construction process of four circular building experiments in the Netherlands have been research. Based on transition and organizational learning literature, for each case the subjects (who learns), the process (learns how), the objects (learns what) and the effect (outcome) have been assessed. The case-studies show that deep learning is achieved in every experiment and that it has changed organizations routines, providing evidence that experiments are an effective means to trigger radical change. However, the potential of transition learning is higher, given the fact that the learning activities in the experiments and structures in the organizations involved were missing or inadequately approached. Therefore, this research recommends to more carefully design experiments to support transition learning. In doing so, this research proposes a typology for transition learning based on seven flavours, which allow researchers to understand, set-up and evaluate transition learning in experiments. Here, combinations of flavours can yield different outcomes. Furthermore, for practitioners a roadmap with checklist questions has been developed to support setting-up future circular building experiments.Industrial Ecolog