In a 40nm BSI CMOS Image Sensor, Direct Bond Interconnect (DBI) requires precise via formations to connect the pixel array to the underlying logic circuits (Engineering Practice).The ILD 6-5 Etch step initiates the pattern transfer from the VIA 7 photoresist into the uppermost inter-layer dielectric stack, setting the stage for subsequent sequential deep etches through underlying layers (ILD 6-4 down to 6-2) A1.By precisely etching this top layer, the process creates the upper section of a high-