Fabrication method of complementary metal oxide semiconductor image sensor

A fabrication method of a CMOS image sensor including a light-receiving element, at least one transistor, a first dielectric layer, a reflective layer, a second dielectric layer, a protective layer, a material layer, a transparent material layer, an optical filter, and a converging element is provided. The light-receiving element and the transistor are disposed respectively inside the light sensing region and the transistor region. The first dielectric layer is disposed on the substrate, covering the transistor and the light-receiving element. The reflective layer is disposed on the first dielectric layer inside the light sensing region. The second dielectric layer is disposed on the first dielectric layer outside the reflective layer. The material layer is disposed on the first dielectric layer inside the reflective layer. The optical filter is disposed on the transparent material layer. The converging element is disposed on the optical filter inside the light sensing region.