In the back-end-of-line (BEOL) process flow, the Pre Litho Cleaning step immediately follows the deposition of the ILD 4-1 and ILD 4-2 layers and precedes the VIA 4 photolithography step A1.As multiple layers are placed on top of each other during IC fabrication, surface irregularities add up, resulting in complex variations for the higher layers P1.This specific cleaning step at the ILD4 level must account for multi-layer topography accumulations that can result in larger inter-level and intra-