Image sensors having grid structure

An image sensor comprising:

• photoelectric conversion elements within a substrate;
• a separation structure within the substrate and between the photoelectric conversion elements;
• an insulating structure on the substrate and the separation structure;
• a plurality of color filters on the insulating structure;
• a protective layer covering the insulating structure and the plurality of color filters;
• and
• a capping layer covering the protective layer,
• wherein a lower end of the capping layer is at a higher level than lower surfaces of the plurality of color filters, and
• the protective layer and the capping layer define an air gap between the plurality of color filters.

An image sensor comprising:

• a lower chip comprising a logic circuit;
• and
• an upper chip on the lower chip, bonded to the lower chip,
• wherein the upper chip comprises:
• photoelectric conversion elements disposed within a substrate;
• a separation structure disposed within the substrate and between the photoelectric conversion elements;
• an insulating structure disposed on the substrate and the separation structure;
• a plurality of color filters disposed on the insulating structure and spaced apart from each other;
• a grid structure disposed between the plurality of color filters, the grid structure comprising a lower horizontal structure disposed on the insulating structure and a vertical structure connected to the lower horizontal structure and covering a side surface of one of the plurality of color filters;
• upper horizontal structures covering upper surfaces of the plurality of color filters;
• a capping layer covering the upper horizontal structures and the grid structure;
• and
• a micro lens disposed on the capping layer,
• wherein the grid structure comprises an air gap surrounded by the vertical structure, the lower horizontal structure, and the capping layer.