ILD 5-1 Deposition is executed directly onto the planarized copper and Ta-based barrier surface following Metal 5 CMP and post-CMP cleaning (Engineering Practice).The primary function of this interfacial layer is to act as a dielectric diffusion barrier (DB) and a copper capping layer (CCL), preventing copper out-diffusion into subsequent inter-metal dielectrics while serving as an etch stop for the upcoming Via 5 patterning P3.Unlike the earlier ILD 1-1 and ILD 3-1 depositions, which cap tightl