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This research studies the impact of the charging effect on the RIE-etched profile of narrow-slot Lead- Selenide (PbSe) gratings. By decreasing the slot width from 4 to 2 𝜇𝑚, we observed the increased irregularity and RIE-lag in etched profiles.We suggest that the charging effect is the main responsible mechanism for this phenomenon. The accumulated charge on the non-conductive photoresist plays a crucial role in forming this effect. Therefore, introducing a conductive layer can neutralize the accumulated charge and significantly improves the profile. To prove this theory, we introduced a thin layer of copper on the gratings. While without any conductive coating, we failed to etch gratings with a slot width of less than 1 𝜇𝑚, by introducing a copper layer, we succeeded etching gratings with 0.7 𝜇𝑚 slot width with the improved sidewall profiles. Hence, this technique enables us to fabricate sub-micron PbSe gratings with applications of mid-infrared (MIR) devices.