Integration of Cu Damascene with Pore-sealed PECVD Porogen Low-k (k=2.5) Dielectrics for 65nm Generation

Owing to the k extendability of porogen LK formed with the incorporation and removal of organic porogen precursors, the porogen LK is the competitive candidate for inter-metal dielectrics (IMDs) of 65nm generation and beyond. However, its porosity raises major challenges in the Cu/LK integration. Chemical and metal penetrability of the porogen LK film revealed the necessity of a protective pore sealing layer in dual damascene. Pore sealing materials were evaluated and SiC_xH_y film demonstrated exceptional barrier property against metal diffusion and good step coverage over the trench profile. By introduction of this SiC_xH_y layer, 10% capacitance reduction was achieved despite the higher k of the material. With the well-controlled thickness, SiC_xH_y pore sealing also demonstrated no via-Rc shift compared to the scheme without pore sealing, therefore excellent protection on the trench structure without via performance degradation was accomplished