Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate;
• a conductive layer on the semiconductor substrate;
• a conductive lower base layer on the conductive layer;
• a first electrode containing Au on the conductive lower base layer;
• insulating films stacked adjacent to the conductive lower base layer;
• a via layer comprising silicon nitride, the via layer covering a part of the insulating films and a part of a top surface of the electrode;
• a second electrode containing Au on the via layer;
• and
• a protective film covering the via layer, a side surface of the second electrode, and a part of a top surface of the second electrode,
• wherein the conductive lower base layer is in direct contact with the conductive layer,
• the conductive lower base layer includes lateral end sections projecting from outermost lateral ends of the electrode in a lateral direction when viewed in a direction perpendicular to a main surface of the semiconductor substrate, a length of each of the lateral end sections of the conductive lower base layer projecting from the outermost lateral ends of the electrode in the lateral direction between the insulating films is 30 nm or more and 1,000 nm or less,
• each of the lateral end sections of the conductive lower base layer is placed between the insulating films,
• a major component of the conductive lower base layer is Ti or W,
• a composition of the lateral end sections of the conductive lower base layer includes O or N in addition to Ti or W, and
• a smallest distance from a top surface of the first electrode to a bottom surface of the second electrode in the direction perpendicular to the main surface of the semiconductor substrate is smaller than a smallest distance from the top surface of the first electrode to a bottom surface of the protective film in the direction perpendicular to the main surface of the semiconductor substrate.