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An ultrasonic time-reversal array system is used to transmit communication signals across an aluminum slab with 195 holes drilled through it. Multiple scattering and mode conversion stretches a 0.4-microsecond transmitted pulse into a received signal that rings for over 75 microseconds with little attenuation. Communication through such a medium is subject to severe multipath distortion. Four variations of a time-reversal receiver are used to mitigate multipath distortion and allow error-free transmission of a variety of bit sequences [see Candy et al. J. Acoust. Soc. Am. Suppl. 115, 2367 (2004)]. Performance of point-to-point receivers constructed from different segments of the Green’s function (channel response) is compared. [This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.]

The extension of 193nm exposure wavelength to smaller nodes continues the trend of increased data complexity and subsequently longer mask writing times. In particular inverse lithography methods create complex mask shapes. We introduce a variety of techniques to mitigate the impact -data simplification post-optical proximity correction (OPC), LShots, multi-resolution writing (MRW) and optimization based fracture. Their potential for shot count reduction is assessed. All of these techniques require changes to the mask making work flow at some level -the data preparation and verification flow, the mask writing equipment, the mask inspection and the mask qualification in the wafer manufacturing line. The paper will discuss these factors and conduct a benefit -effort assessment for the deployment. Some of the techniques do not reproduce the originally targeted mask shape. The impact of the deviations will be studied at wafer level with simulations of the exposure process and quantified as to their impact on the exposure process window. Based on the results of the assessment a deployment strategy will be discussed.