31 March 2014 Lithographic process window optimization for mask aligner proximity lithography
Author Affiliations +
We introduce a complete methodology for process window optimization in proximity mask aligner lithography. The commercially available lithography simulation software LAB from GenISys GmbH was used for simulation of light propagation and 3D resist development. The methodology was tested for the practical example of lines and spaces, 5 micron half-pitch, printed in a 1 micron thick layer of AZ® 1512HS1 positive photoresist on a silicon wafer. A SUSS MicroTec MA8 mask aligner, equipped with MO Exposure Optics® was used in simulation and experiment. MO Exposure Optics® is the latest generation of illumination systems for mask aligners. MO Exposure Optics® provides telecentric illumination and excellent light uniformity over the full mask field. MO Exposure Optics® allows the lithography engineer to freely shape the angular spectrum of the illumination light (customized illumination), which is a mandatory requirement for process window optimization. Three different illumination settings have been tested for 0 to 100 micron proximity gap. The results obtained prove, that the introduced process window methodology is a major step forward to obtain more robust processes in mask aligner lithography. The most remarkable outcome of the presented study is that a smaller exposure gap does not automatically lead to better print results in proximity lithography - what the “good instinct” of a lithographer would expect. With more than 5'000 mask aligners installed in research and industry worldwide, the proposed process window methodology might have significant impact on yield improvement and cost saving in industry.
© (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Reinhard Voelkel, Reinhard Voelkel, Uwe Vogler, Uwe Vogler, Arianna Bramati, Arianna Bramati, Andreas Erdmann, Andreas Erdmann, Nezih Ünal, Nezih Ünal, Ulrich Hofmann, Ulrich Hofmann, Marc Hennemeyer, Marc Hennemeyer, Ralph Zoberbier, Ralph Zoberbier, David Nguyen, David Nguyen, Juergen Brugger, Juergen Brugger, "Lithographic process window optimization for mask aligner proximity lithography", Proc. SPIE 9052, Optical Microlithography XXVII, 90520G (31 March 2014); doi: 10.1117/12.2046332; https://doi.org/10.1117/12.2046332

Back to Top