Sensitive, etch-stable negative e-beam resist for processes without yellow light

The success story of electron beam lithography began in the 1980th with the development of the first PMMA resists. These resists are absolutely light-insensitive in the UV-wavelength range above 300 nm. Clean rooms in which e-beam lithography is performed with PMMA resists require therefore no yellow light.

We have already frequently been asked by e-beam users to also provide negative-tone resists which can be processed under white light conditions. Our negative e-beam resists of the series 7500 – 7700 are all also sensitive in the broadband UV (300 – 405 nm).

These resists are thus well suited for mix&match technologies (e-beam- and UV-lithography in a single process), but absolutely require yellow light. Employing new acid generators which are characterized by a UV-absorption < 280 nm, we developed the chemically enhanced e-beam resist SX AR-N 7700/46 which can also be processed under daylight conditions. Wafers coated with SX AR-N 7700/46 were openly placed in a white-light lab for several hours and then exposed and developed together with resist-coated wafers not subjected to daylight conditions before. Sensitivity and gradation were identical in both test series.