Alternating phase-shifting mask application: effect of width and geometry of shifters, 3D EMF simulation and experimental verification

Armin Semmler; Annika Elsner; Roderick Koehle; Leonhard Mader; Rainer Pforr; Christoph Noelscher; Christoph M. Friedrich; Juergen Knobloch; Uwe A. Griesinger

doi:10.1117/12.435773

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14 September 2001 Alternating phase-shifting mask application: effect of width and geometry of shifters, 3D EMF simulation and experimental verification

Armin Semmler, Annika Elsner, Roderick Koehle, Leonhard Mader, Rainer Pforr, Christoph Noelscher, Christoph M. Friedrich, Juergen Knobloch, Uwe A. Griesinger

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Proceedings Volume 4346, Optical Microlithography XIV; (2001) https://doi.org/10.1117/12.435773
Event: 26th Annual International Symposium on Microlithography, 2001, Santa Clara, CA, United States

Abstract

Besides assist features in combination with HTPSM (half-tone phase shifting mask} and off-axis illumination altPSM (alternating phase shifting mask} is the major resolution enhancement technique to extend optical lithography to low k1. AltPSM in addition has the potential of superior CD control. However to achieve this in production altPSM has to fullfil a number of specifications with respect to phase and transmission. Another important aspect to obtain maximum CD control and overlapping process window for all kinds of structures at different pitches is that the phase shifters need to be optimized. Optimizing shifters by means of simulation results provides valuable input for both setting up design rules for altPSM application and for development of OPC strategies and software. Therefore various systems with different widths of lines and shifters were studied with special focus on basic asymmetric cases. We applied Solid-CM TM, a 3D EMF (electro magnetic field) simulator for our studies. Some results obtained from simulation were experimentally verified by wafer printing results (SEM imaging and CD measurement}. In addition, comparison to 2D simulation results clearly allows the determination of cases in which 3D effects have to be taken into account. The effect of varying shifters is monitored by pattern placement and process window analysis. We apply this investigation to develop solution strategies and to optimize shifter dimensions.

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Armin Semmler, Annika Elsner, Roderick Koehle, Leonhard Mader, Rainer Pforr, Christoph Noelscher, Christoph M. Friedrich, Juergen Knobloch, and Uwe A. Griesinger "Alternating phase-shifting mask application: effect of width and geometry of shifters, 3D EMF simulation and experimental verification", Proc. SPIE 4346, Optical Microlithography XIV, (14 September 2001); https://doi.org/10.1117/12.435773

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