This invention discloses a sensor semiconductor device and a manufacturing method thereof, including: providing a wafer having a plurality of sensor chips, forming a plurality of grooves between bond pads on active surfaces of the adjacent sensor chips; forming conductive traces in the grooves for electrically connecting the bond pads; mounting a transparent medium on the wafer for covering sensing areas of the sensor chips; thinning the sensor chips from the non-active surfaces down to the grooves, thereby exposing the conductive traces; cutting the wafer to separate the sensor chips; mounting the sensor chips on a substrate module having a plurality of substrates, electrically connecting the conductive traces to the substrates; providing an insulation material on the substrate module and between the sensor chips so as to encapsulate the sensor chips but expose the transparent medium; and cutting the substrate module to separate a plurality of resultant sensor semiconductor devices.