Fracture behavior of the copolymers proposed as interlayer dielectric candidates is examined to find the adequate amount of bis(trimethoxysilyl)ethane to methyltrimethoxysilane that can optimize mechanical properties. In spite of the shortcoming that provides a result for comparison purpose, the indentation test becomes a good alternative to estimate cohesive and adhesive fracture strength simultaneously. The scratch test can also be used to evaluate adhesive fracture strength. The similarity between the scratch test and the chemical mechanical planarization Process may offer a clue for predicting the possibility Of failure during fabrication procedure. The sequence of magnitude in critical loads measured from both tests corresponds with that of fracture toughness assessed by the modified edge lift-off test. (C) 2008 Elsevier B.V. All rights reserved.