Several metal-containing molecular inorganic materials are currently considered as photoresists for extreme ultraviolet lithography (EUVL). This is primarily due to their high EUV absorption cross section and small building block size, properties which potentially allow both high sensitivity and resolution as well as low line-edge roughness. The photochemical reaction mechanisms that allow these kinds of materials to function as photoresists, however, are still poorly understood. As a step in this direction, we here discuss photochemical reactions upon deep UV (DUV) irradiation of a model negative-tone EUV photoresist material, namely the well-defined molecular tin-oxo cage compound [(SnR)<sub>12</sub>O<sub>14</sub>(OH)<sub>6</sub>]X<sub>2</sub> (R = organic group; X = anion) which is spin coated to thin layers of 20 nm. The core electronic structure (Sn 3d, O 1s and C 1s) of fresh and DUV exposed films were then investigated using synchrotron radiationbased hard X-ray photoelectron spectroscopy (HAXPES). This method provides information about the structure and chemical state of the respective atoms in the material. We performed a comparative HAXPES study of the composition of the tin-oxo cage compound [(SnR)<sub>12</sub>O<sub>14</sub>(OH)<sub>6</sub>](OH)<sub>2</sub>, either fresh directly after spin-coated vs. DUV-exposed materials under either ambient condition or under a dry N<sub>2</sub> atmosphere. Different chemical oxidation states and concentrations of atoms and atom types in the fresh and exposed films were found. We further found that the chemistry resulting from exposure in air and N<sub>2</sub> is strikingly different, clearly illustrating the influence of film-gas interactions on the (photo)chemical processes that eventually determine the photoresist. Finally, a mechanistic hypothesis for the basic DUV photoreactions in molecular tin-oxo cages is proposed.
Threat evaluation is the process in which threat values are assigned to detected targets, based upon the inferred
capabilities and intents of the targets to inflict damage to blue force defended assets. This is a high-level
information fusion process of high importance, since the calculated threat values are used as input when blue
force weapon systems are allocated to the incoming targets, a process often referred to as weapon allocation.
Threat values can be calculated from a number of different parameters, such as the position of the closest point of
approach (CPA) with respect to blue force defended assets, time required to reach the CPA, the target's velocity,
and its type. A number of algorithms for calculating threat values have been suggested throughout literature,
however, criteria to evaluate the performance of such algorithms seem to be lacking. In this paper, we discuss
different ways to assess the performance of threat evaluation algorithms. In specific, we describe an implemented
testbed in which threat evaluation algorithms can be compared to each other, based on a survivability criterion.
Survivability is measured by running the threat evaluation algorithms on simulated scenarios and using the
resulting threat values as input to a weapon allocation module. Depending on how well the threat evaluation is
performed, the ability of the blue force weapon systems to eliminate the incoming targets will vary (and thereby
also the survivability of the defended assets). Our obtained results for two different threat evaluation algorithms
are presented and analyzed.