Publications

The objective of this project was to Address root cause and implications of thermal runaway of Li-ion batteries by delivering a software architecture solution that can lead to the development of predictive mechanisms that are based on identification of species.

Abstract not provided.

An analysis is presented of a method to protect the reticle (mask) in an extreme ultraviolet (EUV) mask inspection tool using a showerhead plenum to provide a continuous flow of clean gas over the surface of a reticle. The reticle is suspended in an inverted fashion (face down) within a stage/holder that moves back and forth over the showerhead plenum as the reticle is inspected. It is essential that no particles of 10-nm diameter or larger be deposited on the reticle during inspection. Particles can originate from multiple sources in the system, and mask protection from each source is explicitly analyzed. The showerhead plate has an internal plenum with a solid conical wall isolating the aperture. The upper and lower surfaces of the plate are thin flat sheets of porous-metal material. These porous sheets form the top and bottom showerheads that supply the region between the showerhead plate and the reticle and the region between the conical aperture and the Optics Zone box with continuous flows of clean gas. The model studies show that the top showerhead provides robust reticle protection from particles of 10-nm diameter or larger originating from the Reticle Zone and from plenum surfaces contaminated by exposure to the Reticle Zone. Protection is achieved with negligible effect on EUV transmission. The bottom showerhead efficiently protects the reticle from nanoscale particles originating from the Optics Zone. With similar mass flow rates from the two showerheads, this system provides efficient protection even when a significant overpressure exists between the Optics Zone and the Reticle Zone. Performance is insensitive to the fraction of incident particles that sticks to walls, the accommodation coefficient, the aperture geometry, and the gas pressure. The showerheads also protect the aperture (and therefore the Optics Zone) during mask loading and unloading. Commercially available porous-metal media have properties suitable for these showerheads at the required flow rates. The benefits of the approach compared to a conceptual EUV pellicle are described.

The objectives of this project are to address the root cause implications of thermal runaway of Li-ion batteries by delivering a software architecture solution that can lead to the development of predictive mechanisms that are based on identification of species.

Characterizing the explosive dispersal of inert solid particles is of interest in a number of applications. A mixture theory approach is used to calculate the radial motion of the gas-solid mixture as it expands into an infinite atmosphere. Two initial gas-solid configurations are considered. In the first, a core of high pressure gas initially at rest is surrounded by a porous shell of the solid. The other configuration considered is a uniform mixture of solid and gas throughout the sphere. An adaptive finite element method is used to solve the set of partial differential equations for mass, momentum and energy conservation in each phase as well as the compaction equation for the time evolution of solid volume fraction. An adaptive grid scheme is used to refine the mesh to limit discretization errors. This places a fine mesh near the porosity and pressure fronts and greatly reduces the spatial resolution in areas of relatively constant pressure and volume fraction. The dispersal of the solid for the two initial configurations shows quite different behavior. For the gas core and porous shell, the solids are initially compacted to a maximum density of /approximately/80--90% in a very thin region before rapidly dispersing to a broad concentration distribution. For the homogeneous gas-solid sphere, however, there is only a slight compaction region at the leading edge of the expanding gas, and the concentration of solid decays rapidly. 25 refs., 32 figs., 5 tabs.