Semiconductor device and manufacturing method thereof

A semiconductor device comprising:

• a chip mount portion having a chip support surface and a back surface opposite to said chip support surface;
• a semiconductor chip having a main surface, said main surface of said semiconductor chip having a plurality of electrodes, and said semiconductor chip being mounted on said chip support surface of said chip mount portion;
• a plurality of leads each having a sealing surface, a mounting surface opposite to said sealing surface, an inner surface disposed between said sealing surface and said a mounting surface, an outer surface disposed between said sealing surface and said mounting surface and opposite to said inner surface, and a plurality of side surfaces disposed between said sealing surface and said mounting surface and between said inner surface and said outer surface, said plurality of leads being disposed around said chip mount portion,
• a plurality of wires each electrically connected to a respective one of said plurality of electrodes of said semiconductor chip and to a respective one of said plurality of leads;
• and
• a seal member having a main surface, a back surface opposite to said main surface, and a side surface disposed between said main surface and said back surface of said seal member, said seal member sealing said semiconductor chip, a part of each of said plurality of leads, and said plurality of wires such that said mounting surface of each said lead is exposed from said back surface of said seal member;
• wherein each said lead has a first inner portion with said sealing surface intersecting said inner surface, and a second inner portion with said mounting surface intersecting said inner surface;
• wherein said first inner portion is nearer to said outer surface than said second inner portion;
• wherein a width of said sealing surface in a direction intersecting a respective extending direction of each said lead is wider than a width of said mounting surface in said intersecting direction.