The Pre Litho Cleaning step in the LS_GRID module serves as the critical surface preparation interface between the deposition of the Upper Grid Seal Layer and the subsequent Green Color Filter (CFA) Coat and Develop steps P1, A3.Unlike standard front-end pre-lithography cleans that prepare the substrate for sacrificial photoresists used in plasma etching (such as earlier flow steps #7 or #13), this specific step prepares an optical seal layer to receive a permanent, dye-doped polymer color filte