According to an embodiment of the invention, a chip package is provided, which includes: a substrate having an upper surface and a lower surface; a hole extending from the upper surface toward the lower surface; an insulating layer located overlying a sidewall of the hole; and a material layer located overlying the sidewall of the hole, wherein the material layer is separated from the upper surface of the substrate by a distance and a thickness of the material layer decreases along a direction toward the lower surface.