Back-illuminated semiconductor photodetection element

A back-illuminated semiconductor photodetector, comprising:

• a semiconductor substrate including a first main surface and a second main surface opposing each other;
• a plurality of pad electrodes;
• a plurality of bump electrodes each disposed on a corresponding pad electrode of the plurality of pad electrodes and electrically connected to the corresponding pad electrode;
• and
• an insulating film disposed on the second main surface of the semiconductor substrate, wherein
• the semiconductor substrate includes a first semiconductor region of a first conductivity type, and a plurality of second semiconductor regions of a second conductivity type, the second semiconductor regions provided in a side of the second main surface and constituting pn junctions with the first semiconductor region,
• each of the plurality of second semiconductor regions includes a first region including a textured surface, and a second region where a corresponding bump electrode of the plurality of bump electrodes is disposed,
• the insulating film includes a first insulating film covering surfaces of the plurality of second semiconductor regions, and a second insulating film covering peripheries of the pad electrodes,
• the pad electrode includes a first electrode region disposed on the second region and in contact with the second region, and a second electrode region continuous with the first electrode region and disposed on at least a part of a region included in the first insulating film and corresponding to the first region,
• the first main surface is a light incident surface of the semiconductor substrate.