Delay-time and aging effects on contrast and sensitivity of hydrogen silsesquioxane

3Hydrogen silsesquioxane (HSQ) has been shown to behave as a negative tone inorganic e-beam resist with a resolution better than 20 nm established. In this article, delay-time and aging effects on contrast and sensitivity have been investigated. The effect of a 1 week delay in air between softbake and exposure is much larger than either the aging effect or the effect of the softbake temperature. A pre-exposure delay in air seems to decrease the sensitivity and to enhance the contrast of HSQ. A general correlation between sensitivity and contrast has been established for various pre-exposure and postexposure treatments for 20, 50, and 100 kV exposures. The possible causes for the various delay-time effects are discussed. (C) 2002 American Vacuum Society.