Solid state imaging element with bus breakage detector

Abstract

A solid state imaging element includes a plurality of photodetectors arranged in a two-dimensional array on a semiconductor substrate, first and second charge transfer circuits for transferring signal charges in a vertical direction and a horizontal direction, respectively, a plurality of transfer gates for controlling charge transfer from the photodetectors to the first charge transfer circuit, a scanner for controlling switching of the transfer gates, a plurality of bus lines connecting the transfer gates with the scanner, and a bus line breakage checking circuit. The bus line breakage checking circuit includes a plurality of transistors connected in series with respective bus lines, a test pad connected with the bus lines through the transistors, and a voltage applying pad for applying a voltage to control switching of the transistors. Therefore, the breakage of a bus line can be detected in a wafer test without actually operating the element, whereby time and money are saved.