Bizhong Zhu

Mechanical Properties and Toughening of a Polymethylsilsesquioxane Network

Polysilsesquioxanes are finding wider uses in microelectronics. However these materials are brittle and their mechanical behaviors need to be better understood. In this paper the mechanical properties of a cured methyl silsesquioxane network are studied and they are found to vary strongly with curing conditions. In the investigated curing temperature range there seems to be a correlation between the fracture toughness (K Ic ) and the viscoelastic transitions, which are affected by the network crosslink density. A higher crosslink density suppresses the cc and β transitions and reduces the K Ic . A toughening approach is designed and its applicability is demonstrated by the increased fracture toughness.