Non-chemically amplified resists for 193-nm immersion lithography: Influence of absorbance on performance

The feasibility of three polymer systems for use as non chemically amplified resists for 193 nm lithography are discussed. The three systems are polycarbonates, polyphthalaldehydes and polysulfones. In general it was found that increased absorbance resulted in higher sensitivity to 193 nm light. However, the exception to this was the polycarbonates, which were found to undergo crosslinking due to an alkene group present in the polymer backbone. Although polyphthalaldehydes were very sensitive, their absorbance values were too high to be useful in a commercial environment. Absorbing polysulfones were found to be sensitive to 193 nm light and initial patterning results have been presented

Non-CA resists for 193nm immersions lithography: Effects of chemical structure on sensitivity

Initial studies are presented on the use of polysulfones as non-chemically amplified resists (non-CARs) for 193 nm immersion lithography. Polynorbornene sulfone films on silicon wafers have been irradiated with 193 nm photons in the absence of a photo-acid generator. Chemical contrast curves and contrast curves were obtained via spectroscopic ellipsometry and grazing angle - attenuated total reflectance FTIR spectroscopy. Results were consistent with previously reported mechanisms for the degradation of aliphatic polysulfones with ionizing radiation. It was shown that E0 values could be reduced significantly by using a post exposure bake step, which propagated depolymerization of the polymer. Initial patterning results down to 50 nm half pitch were demonstrated with EUV photons

Polysulfone based Non-CA resists for 193nm immersion lithography: Effect of increasing polymer absorbance on sensitivity

The use of norbornene-based polysulfones as non-chemically amplified resists (non-CARs) for 193 nm immersion lithography was explored. Allylbenzene was incorporated into the polymer backbone to increase the absorbance of the polymers. The effect of polymer absorbance on sensitivity to 193 nm radiation was investigated. Polymer films on silicon wafers have been irradiated with 193 nm photons in the absence of a photo-acid generator. Chemical contrast curves (film thickness versus dose plots prior to solvent development) and contrast curves (film thickness versus dose plots after solvent development) were obtained by spectroscopic ellipsometry. The results show that E0 values could be reduced significantly by increasing the absorbance of the polymer

Virtual histology of cortical thickness and shared neurobiology in 6 psychiatric disorders

Importance Large-scale neuroimaging studies have revealed group differences in cortical thickness across many psychiatric disorders. The underlying neurobiology behind these differences is not well understood. Objective To determine neurobiologic correlates of group differences in cortical thickness between cases and controls in 6 disorders: attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), bipolar disorder (BD), major depressive disorder (MDD), obsessive-compulsive disorder (OCD), and schizophrenia. Design, Setting, and Participants Profiles of group differences in cortical thickness between cases and controls were generated using T1-weighted magnetic resonance images. Similarity between interregional profiles of cell-specific gene expression and those in the group differences in cortical thickness were investigated in each disorder. Next, principal component analysis was used to reveal a shared profile of group difference in thickness across the disorders. Analysis for gene coexpression, clustering, and enrichment for genes associated with these disorders were conducted. Data analysis was conducted between June and December 2019. The analysis included 145 cohorts across 6 psychiatric disorders drawn from the ENIGMA consortium. The numbers of cases and controls in each of the 6 disorders were as follows: ADHD: 1814 and 1602; ASD: 1748 and 1770; BD: 1547 and 3405; MDD: 2658 and 3572; OCD: 2266 and 2007; and schizophrenia: 2688 and 3244. Main Outcomes and Measures Interregional profiles of group difference in cortical thickness between cases and controls. Results A total of 12 721 cases and 15 600 controls, ranging from ages 2 to 89 years, were included in this study. Interregional profiles of group differences in cortical thickness for each of the 6 psychiatric disorders were associated with profiles of gene expression specific to pyramidal (CA1) cells, astrocytes (except for BD), and microglia (except for OCD); collectively, gene-expression profiles of the 3 cell types explain between 25% and 54% of variance in interregional profiles of group differences in cortical thickness. Principal component analysis revealed a shared profile of difference in cortical thickness across the 6 disorders (48% variance explained); interregional profile of this principal component 1 was associated with that of the pyramidal-cell gene expression (explaining 56% of interregional variation). Coexpression analyses of these genes revealed 2 clusters: (1) a prenatal cluster enriched with genes involved in neurodevelopmental (axon guidance) processes and (2) a postnatal cluster enriched with genes involved in synaptic activity and plasticity-related processes. These clusters were enriched with genes associated with all 6 psychiatric disorders. Conclusions and Relevance In this study, shared neurobiologic processes were associated with differences in cortical thickness across multiple psychiatric disorders. These processes implicate a common role of prenatal development and postnatal functioning of the cerebral cortex in these disorders