Image Sensor Metal Layer ESD Protection via Localized Exposure

The patent applies local quality by creating different exposure widths of the metal layer at different locations. Specifically, the protection layer exposes the metal layer with a first width at first and second locations, and a second width (smaller than the first width) at third and fourth locations. This localized variation in exposure width allows controlled ESD dissipation at critical areas while minimizing exposed area at other locations, thus resolving the contradiction between reliable charge dissipation and minimizing exposed metal area.

The patent applies preliminary anti-action by pre-configuring the protection layer to expose the metal layer with controlled widths before the etching process. This pre-arranged exposure structure creates safe discharge paths for electrostatic charges that will accumulate during the subsequent bond pad and scribe line opening etching step. The exposed metal areas are designed in advance to prevent charge accumulation to dangerous levels, thus counteracting the harmful ESD effect before it can occur during manufacturing.