Semiconductor device and mounting structure thereof

A semiconductor device, comprising:

• a semiconductor element;
• a first lead, being rectangular in shape when viewed in a thickness direction, comprising a mounting portion, four connecting portions and four first terminal portions, wherein the semiconductor element is mounted on the mounting portion, the connecting portions extend from four corners of the mounting portion, respectively, and the first terminal portions are connected to front ends of the plurality of connecting portions respectively;
• a plurality of second lead, arranged, when viewed in the thickness direction, in a plural quantity in parallel to each edge of the mounting portion between the adjacent first terminal portions;
• and
• a sealing resin, covering at least a part of each of the first lead and the second leads;
• wherein,
• a part of each first terminal portion is exposed from the sealing resin,
• each second lead comprises a second terminal portion and a joining portion, a part of the second terminal portion is exposed from the sealing resin, and the joining portion extends from the second terminal portion toward the mounting portion, and
• a connecting portion width of the connecting portion is greater than a joining portion width of the joining portion, the connecting portion width is a dimension in a direction perpendicular to an extension direction of the connecting portion and the thickness direction, and the joining portion width is a dimension in a direction perpendicular to an extension direction of the joining portion and the thickness direction.