Curvilinear mask process correction: status quo and outlook

Abstract

Due to the increasing availability of Multi Beam Mask Writers (MBMW) and the associated wafer lithography benefits, efficient handling of curvilinear mask shapes in the post tape-out flow becomes increasingly important. The presence of complex curvilinear mask shapes generated by Inverse Lithography Technology (ILT), or similar techniques requires new features and algorithms, especially in the context of applying Mask Process Correction (MPC). This paper discusses the status of Curvilinear Mask Process Correction (CLMPC) and gives a brief outlook into the near future of handling curvilinear mask shapes in the post tape-out flow. A summary of MRC requirements for incoming data and implications for mask inspection are included as well to put CLMPC into the right context. Further, approaches for CLMPC file size compaction along with new methods of data representation based on native curve formats are also discussed.

Efficient exposure of non-Manhattan layouts for optical applications using variable shaped beam lithography

“…With MIA, that effect is completely avoided since only smooth input functions instead of piecewise linear data are approximated. Note that the upcoming extension of the OASIS standard will also include smooth Bezier and Spline curve data representation in a new MULTIGON record 8 , 9 . MIA will thus be applicable directly also to such curvilinear data.…”