Dual‐inlaid Cu interconnects with different overburden thicknesses were fabricated and subsequently annealed applying identical conditions. The microstructure in trenches was characterized by electron backscatter diffraction (EBSD) before and after chemical mechanical polishing (CMP). For samples subjected to CMP, grain size and texture were determined from top‐view EBSD scanning on arrays of trenches. Smaller grain size and stronger Cu (111) texture were observed in the samples with thinner overburden layer. Further EBSD investigations were carried out on cross‐sections of trenches in samples not subjected to CMP which suggested interplay of grain growth mechanism in trench and overburden.