BACK SURFACE INCIDENT TYPE SEMICONDUCTOR PHOTO DETECTION ELEMENT

A semiconductor substrate includes a first main surface and a second main surface opposing each other. The semiconductor substrate includes a first semiconductor region of a first conductivity type, and a plurality of second semiconductor regions constituting pn junctions with the first semiconductor region. The semiconductor substrate includes the plurality of second semiconductor in a side of the second main surface. Each of the plurality of second semiconductor regions includes a first region including a textured surface, and a second region where a bump electrode is disposed. A thickness of the first region at a deepest position of recesses of the textured surface is smaller than a distance between a surface of the second region and the deepest position in a thickness direction of the semiconductor substrate. The first main surface is a light incident surface of the semiconductor substrate.