Method of preparing light-sensitive integrated circuits for packaging

Abstract

A process for preparing a light-sensitive integrated circuit (IC) for packaging that provides a reduced exposure of the light-sensitive IC to light. The process includes providing a semiconductor substrate (e.g., a silicon wafer) with a plurality of light-sensitive ICs formed in/on its upper surface. The lower surface is optionally coated with opaque material. Next, the semiconductor substrate is diced to form individual light-sensitive ICs, each of which has a semiconductor substrate lower surface and semiconductor substrate lateral edges. The semiconductor substrate lateral edges (and optionally backside) are then spray coated with an opaque material (e.g., opaque ink) to form an opaque layer covering the semiconductor substrate lateral edges. The opaque layer prevents light from entering the semiconductor substrate through the lateral edges and interfering with the operation of the light-sensitive IC. The inventive process is simple and inexpensive, employing, for example, piezoelectric injectors to spray coat opaque ink on the semiconductor substrate lateral edges as the individual ICs are conveyed through a pass-through. In addition, processes according to the present invention are independent of the techniques used to manufacture the light-sensitive ICs and, therefore, provide for increased packaging process flexibility and economy.