{'fraction_non_alphanumeric': 0.02091503267973856, 'fraction_numerical': 0.00130718954248366, 'mean_word_length': 6.092592592592593, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Nondestructive stiffness and density characterization of porous low-k films by surface acoustic wave spectroscopy

Nanoporous methylsilsesquioxane (MSSQ) films are a leading candidate for low dielectric constant (k) materials for microelectronic interconnects. Mechanical strength reduces rapidly with lower k (increasing porosity) however, and there is a lack of techniques to characterize these properties in the k /spl les/ 2 range. This work reports surface acoustic wave spectroscopy characterization of density/porosity and Young's modulus values of a range of methylsilsesquioxane films from different manufacturers. We show that the results are validated by independent measurements and that nanoindentation measurements consistently overestimate stiffness.