An image sensor includes a pixel array chip, a logic chip, and an interposed layer. The interposed layer is disposed on the pixel array chip. The logic chip is disposed on the interposed layer. The interposed layer includes a connecting part, a shielding part, and a metal-diffusion barrier layer. The connecting part electrically connects a first interconnection wire of the pixel array chip and a second interconnection wire of the logic chip. The connecting part includes a first metallic element. The shielding part is disposed spatially apart from the connecting part and electrically grounded to suppress an electrical coupling between the pixel array chip and the logic chip. The shielding part includes a second metallic element. The metal-diffusion barrier layer is disposed on top and bottom surfaces of the interposed layer to limit diffusion of electrical charges to the pixel array chip and the logic chip.