Micro projection lithography using microlens on a mask

Chang Hyeon Ji, Florian Herrault, Mark G. Allen

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


A micro projection lithography process has been implemented using a photomask having arrays of cylindrical or spherical plano-convex microlenses formed by thermal reflow in proximity exposure mode. This approach provides a practical means to generate patterns inside deep cavities without proximity-based pattern size increases. The generated pattern size can be controlled by controlling the focal depth of the microlens. A maximum pattern size reduction of 62% has been achieved at the bottom of a 216 νm deep trench with a cylindrical microlens having a focal length of 254 νm for a 60 νm square pattern. The effect of the microlens on the lithography process, including the relationship between the focal depth, exposure dose and pattern size, has been analyzed.

Original languageEnglish
Article number127003
JournalJournal of Micromechanics and Microengineering
Issue number12
StatePublished - 2009


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