A method is proposed to produce an optical sensor at wafer-level, the methods comprises the following steps. A wafer is provided and has a main top surface and a main back surface. At or near the top surface of the wafer at least one integrated circuit is arranged having a light sensitive component. A first mold tool is placed over the at least one integrated circuit such that at least one channel remains between the first mold tool and the top surface to enter a first mold material. A first mold structure is formed by wafer-level molding the first mold material via the at least one channel. The first mold material creates at least one runner structure. A second mold tool is placed over the first mold structure and a second mold structure is formed by wafer-level molding a second mold material by means of the second mold tool. A light path blocking structure is arranged on the top surface to block light from entering via the at least one runner structure.