Hydrogen silsesquioxane (HSQ) is used as a high-resolution resist with resolution down below 10 nm half-pitch. This material or materials with related functionalities could have widespread impact in nanolithography and nanoscience applications if the exposure mechanism was understood and instabilities controlled. Here we have directly investigated the exposure mechanism using vibrational spectroscopy (both Raman and Fourier-transform infrared) and electron-beam-induced desorption spectroscopy (EBID). In the non-networked HSQ system, silicon atoms sit at the corners of a cubic structure. Each silicon is bonded to a hydrogen atom and bridges three oxygen atoms (formula: HSiO 3/2). For the first time, we have shown, via changes in the Si H 2 peak at ∼2200 cm-1 in the Raman spectra and the release of SiHx products in EBID, that electron-beam-exposed material cross-links via a redistribution reaction. In addition, we observe the release of significantly more H2 than SiH2 during EBID, which is indicative of additional reaction mechanisms. Furthermore, we compare the behavior of HSQ in response to both thermally and electron-beam induced reactions.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics|
|State||Published - May 2010|
Bibliographical noteFunding Information:
The authors would like to thank Adam Schwartzberg for useful discussions on Raman Spectra, Professor Thomas Klassen, Head of the Student Exchange Program at Helmut-Schmidt University, and Babak Sanii. This work was performed at the Molecular Foundry, Lawrence Berkeley National Laboratory, and was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. A. S. was supported by the student exchange program at Helmut-Schmidt University. B.C. was supported by Vistec Lithography, Inc.