Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 02 processing: Difference between revisions
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The lithographic result of exposure on Aligner: Maskless 02 depends on a lot of factors, including the dose and defocus parameters, and the exposure mode used. The optimal dose and defocus depend on the thickness of the resist, and the optical properties of the substrate (e.g. reflective/absorbing/transparent). All of these factors influence the obtainable resolution, as well as the writing speed. | The lithographic result of exposure on Aligner: Maskless 02 depends on a lot of factors, including the dose and defocus parameters, and the exposure mode used. The optimal dose and defocus depend on the type and thickness of the resist, and the optical properties of the substrate (e.g. reflective/absorbing/transparent). All of these factors influence the obtainable resolution, as well as the writing speed. | ||
The correct way to determine the best dose-defocus settings is to generate a so-called Bossung plot (known from projection lithography), which plots the printed linewidth as a function of dose and defocus. From this, the most stable region of parameter space is chosen, i.e. the region where the linewidth changes the least when dose and defocus changes. Any deviation from the design linewidth can be corrected using the CD bias parameter. This typically involves SEM imaging of resist cross-sections, and quickly becomes time consuming. However, in most cases, inspection of a dose-defocus matrix (easily generated using the series exposure function) in an optical microscope will get you most of the way. | |||
==Exposure dose== | ==Exposure dose== | ||