An integrated circuit chip imager based on stacked packaging which is used for decoding bar codes comprises a first integrate circuit chip and a second integrate circuit chip. The first integrate circuit chip comprises a wafer level camera, at least one light source, and a plurality of contact mats on one surface of the first integrate circuit chip and a second integrated circuit chip. The second integrate circuit chip comprises a processor, a memorizer, a plurality of contact mats on one surface of the second integrate circuit chip and a plurality of contact mats on the other surface of the second integrate circuit chip. The device comprises a PCB which comprises a plurality of contact mats which are positioned on at least one surface of the PCB. The first integrate circuit chip and the second integrate circuit chip are vertically stacked on the PCB, and the plurality of contact mats on the first integrate circuit chip and on the second integrate circuit chip and on the PCB are butt-jointed. The integrated circuit chip imager based on stacked packaging is operated in order to process the image generated by WLC and try to decode the bar code.