Time temperature and other process variables in the warm water Intermediate Development Bake

Use of a warm water soak midway during development results in improved resist profiles, particularly as a function of focus. Three positive resists are examined in order to qualitatively determine their particular time temperature response to such a process. We find that the expected trade off between temperature and time holds, furthermore there is no need to spin dry wafers during treatment. Control of the time and temperature gives rise to improved profiles relative to samples utilising interrupted development. The warm water IDB also requires lower overheads in development time, as well as being applicable to a wider range of Novolac/DNQ chemistries. The use of multiple warm water IDB treatments may be required in extending the focus latitude of both lines and contacts printed over topography.