Analysis of HSG-7000 silsesquioxane-based low-k dielectric hot plate curing using Raman spectroscopy

HSG-7000 by Hitachi Chemicals Ltd., is a spin-on low-k dielectric offering a dielectric constant of approximately 2.2. It is a silsesquioxane based low-k dielectric with an empirical formula of [CH3–SiO3/2]n. The standard thermal curing for HSG 7000 is at least 30 min at 400 °C with N2 ambient. This paper aims to demonstrate that curing using a low-cost hot plate in atmospheric ambient is possible. The chemical bonding structure will be studied using Raman spectroscopy. The ratios of the areas of the Si–O–Si /Si–CH3 of the Raman bands were used to determine the structure of the different hot plate curing temperatures and time. Results showed that hot plate curing at 425° for 15 min will yield a ratio closest to those cured with the standard furnace process which is predominantly ladder structure. The results also show that the dielectric constant remains essentially constant with different hot plate curing temperatures and time.