A chip scale package structure is provided. The chip scale package structure includes an image sensor chip and a chip. The image sensor chip includes a first redistribution layer including a conductive wire and a conductive pad formed on the conductive wire, wherein the conductive pad is exposed from the surface of the first redistribution layer. The chip includes a second redistribution layer including a conductive wire and a conductive pad formed on the conductive wire, wherein the conductive pad is exposed from the surface of the second redistribution layer. The area of the chip is smaller than that of the image sensor chip. The second redistribution layer of the chip bonds to the first redistribution layer of the image sensor chip.