The foundations of leading edge DRAM manufacturing are built on accurate EUV lithography exposures in close synergy with cutting-edge immersion layers as well as advanced patterning schemes (e.g. self-aligned multiple patterning). Final device yield critically depends on the subsequent and accurate stacking of multiple layers with device features of precise width and edge placement. To support the ever-decreasing requirements for both the EUV as well as the DUV, (edge) placement accuracy, scanner enhancements are required on both platforms.In this paper we report on the improvements of the NXT:2100i immersion scanner to further reduce the (edge) placement errors within the die (intra-field) and across the full wafer (inter-field). The NXT:2100i incorporates a new projection optics with built-in distortion manipulator that extends the intra-field correction capability for both X and Y directions. The external overlay interface is extended with the distortion manipulator degrees of freedom to handle high spatial frequent distortion data of a to-be-matched scanner or high spatial frequent overlay fingerprints measured by after develop or after etch metrology. Thermal conditioning of the reticle is improved with a fast conditioned internal reticle library resulting in lower reticle-to-reticle temperature variation. Improved lens metrology (aberrations) and reticle align accuracy (alignment/overlay) is achieved with a better integrated image sensor. Improved alignment accuracy and reduced alignment process dependencies for wafer alignment are realized with 12-colors parallel measurements and by adding more alignment marks measurements at the wafer measure side without throughput impact. In concert with the hardware components, various software algorithms are updated, yielding improved inter-and intra-field overlay setup and improved reticle heating induced overlay.We will detail the specific module performance items as well as the system performance of the NXT:2100i scanner, both in reference (DRAM relevant overlay) to DUV as well as to EUV scanners.

In order to create high amplitudes (p'/p0>10%) for a relatively low frequency range (between 5 and 125 Hz), a large subwoofer is connected to a resonator tube by an exponential horn. A parallel-plate stack, with various plate thicknesses and separations, can be placed at different positions in the resonator tube. The position of the subwoofer membrane, the voltage and current of the subwoofer, as well as the pressure at six different positions in the resonator is measured. The measurements are in good agreement with simulations. Using a multi-microphone method the transfer matrix of a stack is determined experimentally. Using a PIV method a 2-D velocity field between and around the stack plates is measured. The vortex shedding at the end of stack plates is studied in particular. The amplitude, frequency, plate thickness, plate separation and plate-ending shape are varied. Also the streaming velocity field is studied. Small asymmetries in the geometry have a huge influence on the streaming velocity.