A commercial g-line photoresist (Shipley S-1805) can be used, but has to be thinned to provide sub-wavelength thickness when spun onto a silicon substrate. A vacuum chuck ensures that the substrate and membrane mask are in intimate contact. Optimum results for reproducing 50 nm features were obtained using photoresist diluted 1:4 in PGMEA (60 nm thickness after spin coating) and an exposure time of 70 s. It should be noted that no strong feature-size dependent exposure times have been observed in these experiments. This has been demonstrated by the ability to pattern micron-scale and nanometre-scale features at the same time and from the same mask
Was this article helpful?
Have you ever been envious of people who seem to have no end of clever ideas, who are able to think quickly in any situation, or who seem to have flawless memories? Could it be that they're just born smarter or quicker than the rest of us? Or are there some secrets that they might know that we don't?