The thermal accumulation improvement is based on laser epitaxial growth for monolithic 3D-ICs manufacturing. We propose one structure which has a thermal conduction layer such as Cu in ILD oxide layer. To reduce the Via depth and ILD oxide thickness can improve the re-crystallization quality for upper Si layer. With the conduction Cu layer, the Via depth can reduce to 200 nm, and the maximum temperature of the 1 8t layer poly gate and source/drain maintains as low as .....,320K and .....,350K, respectively, for laser re-crystallization annealing.