Some embodiments include methods of forming openings in which a metal-containing structure is formed over a region of a semiconductor substrate. A patterned metal-containing material is formed over the metal-containing structure, with the metal-containing material having a gap extending therethrough. An entirety of the metal-containing structure is removed through the gap to leave an opening over the region of the semiconductor substrate. The region of the semiconductor substrate may comprise CMOS sensors, and one or both of filter material and microlens material may be formed within the opening.