A semiconductor device is provided. The semiconductor device includes a substrate. The substrate includes a plurality of pixels. The semiconductor device also includes a light collimator layer disposed on the substrate. The light collimator layer includes a transparent connection feature disposed on the substrate, and a plurality of transparent pillars disposed on the transparent connection feature. The plurality of transparent pillars cover the plurality of pixels, and the transparent connection feature connects to the plurality of transparent pillars. The plurality of transparent pillars and the transparent connection feature are made of a first material which includes a transparent material. The light collimator layer also includes a plurality of first light-shielding features disposed on the transparent connection feature. The top surface of one of the transparent pillars is level with the top surface of one of the first light-shielding features.