Scanning x-ray microscopy investigations into the electron-beam exposure mechanism of hydrogen silsesquioxane resists

Electron-beam exposed hydrogen silsesquioxane cross-linking chemistry is investigated by scanning transmission x-ray microscopy (STXM) and atomic force microscopy (AFM). Using STXM, a maximum in the chemical contrast is obtained by measuring, the x-ray absorption at 535.4 eV, corresponding to the 1s K-edge transition in oxygen. An area-dependent and dose-dependent chemical conversion is observed for feature sizes between 150 nm and 10 mu m and doses between 0.4 and 40 mC/cm(2). The activated (cross-linked) regions extend beyond the exposure zones, especially for higher dosed exposures. With AFM, thickness changes in the latent images (e-beam exposed but undeveloped) are observed, which also display a dependence on exposed area. Potential mechanisms, involving chemical diffusion outside the exposure zone, are discussed. (c) 2006 American Vacuum Society.