Low-k dielectric modulus metrology
Beyond 65nm node, the incorporation of low-k dielectrics as inter layer dielectrics (ILD) in Cu interconnect structures to improve device performance has created a number of challenges. The thermo-mechanical reliability is a concern due to the inherent fragility of these materials. The Young's modulus of the inter level dielectrics (ILD) can be directly correlated to peeling and cracking defects that may not become obvious until the die reaches final packaging.
Accurate measurement of the ILD modulus provides a good predictor of its ability to withstand chemical mechanical planarization (CMP) and packaging stresses and ensures that the final device yield and long term reliability are robust.