Abstract: The present invention provides an image sensor and a method for fabricating the image sensor. The image sensor includes a semiconductor substrate, photodiodes (PD), deep isolation trenches, first deep P-well blocks and second deep P-wells. The isolation trenches surrounds the PDs, and each of the isolation trenches is separated from any adjacent isolation trenches at a crossing where they would have crossed each other if they further extended. The first deep P-wells blocks have projections on the semiconductor substrate, which encompass projections of said separated portions of the isolation trenches on the semiconductor substrate. The first P-well blocks can be formed using only one photomask, resulting in a reduction in cost.

Abstract: A method for manufacturing a semiconductor device may include the following steps: preparing a substrate; providing a gate material layer that overlaps the substrate; providing a blocking layer that partially covers the gate material layer; removing a portion of the gate material layer that is not covered by the blocking layer for forming a gate electrode; providing a blocking material layer that covers both the blocking layer and the substrate; removing a portion of the blocking material layer for forming a blocking member that has an opening, wherein the opening partially exposes the blocking layer and partially exposes the substrate; and performing ion implantation through the opening to form a doped well region in the substrate.