Today low-k dielectric materials are integrated into computer chips to improve the operation speed and reduce the cross-talk noise. Due to weak mechanical properties of low-k dielectric materials, cohesive failure is subjected to occur. Channel cracking is one common mode of cohesive failure. In this term paper, several potential issues relevant to channel cracking of low-k dielectric thin films are reviewed. These issues include the well known substrate constrain effect; the concentration of crack driving force due to patterned structure, and the degrading of fracture toughness as scaling down the dielectric constant of the films. Some design rules of applying the low-k dielectric thin films are also discussed in this report.