VIA 7 (DBI Via) - Photo is a critical lithography step in the back-end-of-line (BEOL) Direct Bond Interconnect (DBI) module for 40nm BSI CMOS Image Sensors P2.Following the preceding ILD ashing and strip/clean processes, this step defines the vertical conduits that will electrically connect the underlying metal layers to the topmost DBI pads T1.In a via-first dual-damascene integration scheme, the via pattern is defined before the trench, necessitating precise alignment to prevent edge placement