| 초록 |
Poly(methyl silsesquioxane) (PMSSQ) has become important as low-dielectric insulators in advanced microelectronic devices, but its mechanical properties are still questionable for chemical mechanical polishing (CMP) process when higher porosity is introduced to obtain lower dielectric constant (k). We copolymerized methyl trimethoxysilane (MTMS) with bis-(1,2-trimethoxysilyl)ethane (BTMSE) for higher mechanical properties and better compatibility with porogens such as poly(carprolactone)s. In this study, we investigated the changes in microstructures and various properties of poly(MTMS-co-BTMSE) (MTMS:BTMSE = 9:1, mol ratio) as a function of molecular weight of prepolymers using FT-IR, TGA, nanoindenter and Si-NMR. As the molecular weight of prepolymers decreased, both refractive indices and k values of poly(MTMS-co-BTMSE) linearly increased, which might be related to the increase in residual Si-OH group. In addition, the modulus and hardness of poly(MTMS-co-BTMSE) decreased with the molecular weights of prepolymers. This may be associated with decrease in cage-like structures and increase in cross-linking density with decreasing molecular weight of prepolymers. |
