The progress of developer base into films of terpolymers of norbornene-maleic anhydride and acrylic acid was shown to be a percolation process with a critical site concentration of x(c) ) 0.084, implying that every acrylic acid site in the terpolymer makes 12 monomer units of the polymer water compatible. Using these terpolymers, the dissolution inhibition mechanism for two types of common additives, tert-butyl carboxylate (e.g., cholates, cyclohexanecarboxylates, and malonates) dissolution inhibititors and onium salt photoacid generators (PAG's), were examined. Additionally, the dissolution promotion mechanism of carboxylic acids released from acidolysis of tert-butyl esters was investigated. For a wide range of cholates and other tert-butyl carboxylate derivatives, increasing hydrophobicity is a good predictor of increased dissolution inhibition. The molar dissolution promotion ability of a carboxylic acid increases with increasing number of both carboxyl and hydroxyl ester functional groups. For onium salt PAG's, a decrease in dissolution inhibition occurred when increasing the hydrophobicity and size of counteranions. Rather than being tied to hydrophobicity, large changes of dissolution inhibition in this class of materials appear to correlate with their ability to interact with carboxyl groups.
The bulge test provides a convenient way to measure the mechanical properties, including fracture strength, of thin ceramic membranes. Thin (≈ 3000Å) films of non-stoichiometric SiNx, nominally defect-free and containing flaws introduced byfocused ion-beam machining, were examined. The use of such membranes in masks for projection electron-beam lithography systems makes it important to determine their ultimate strength and reliability. The mean fracture strength of the defect-free membranes was found to be 1.79±0.04GPa, and the Weibull modulus was estimated to be 49±15, giving a safe operating stress of 1.5GPa. The results of fracturing the samples containing flaws indicated that holes smaller than 15x0.5μm had no effect on the fracture strength of the membranes. By estimating the stress concentration factor for the slots, it was determined that the critical fracture stress was 16±3GPa.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.