Lithography Performance of Contact Holes-Part I. Optimization of Pattern Fidelity Using MPG and MPG-II

摘要

Proximity effects make optimizing the pattern fiedlity of contact holes one of the most challenging lithographic tasks in maskmaking. This paper examines the exposure and process parameters that influence the pattern fidelity of contact holes on a photomask from both a modeling and an experimental approach. To optimize contact critical dimension (CD) uniformity and corner rounding, a rnage of exposure and process variables is examined. These variables include MEBES~circleR writing strategy (which is multipass gray, also known as MPG, and MPG-II), input address, spot size, development time, and data bias. ProBEAM/3D, an electron-beam (e-beam) modeling software program, is used to model contact hole performance, and the results are verified with a design of experiments protocol using the same variables as in the simulation study. A simultaneous optimization of these parameters is instructive in matching the appropriate writing strategy and technology node with the desired quality of the contact hole.