Method of manufacturing a semiconductor device

A method of manufacturing a semiconductor device comprising the steps of:

• preparing a wiring substrate having a semiconductor chip mounted over its main surface;
• preparing, when the wiring substrate is arranged between an upper die and a lower die, a molding die having a resin sealing member forming section positioned over the main surface of the wiring substrate so as to cover the semiconductor chip mounted over the wiring substrate, a first resin flowing path crossing a first side of the wiring substrate from the outside of the wiring substrate to communicate with the resin sealing member forming section, and a second resin flowing path positioned over the main surface of the wiring substrate at a second side of the wiring substrate that is opposite to the first side thereof to communicate with the resin sealing member forming section;
• forming a resin sealing member that resin-seals the semiconductor chip mounted over the wiring substrate, arranged between the upper die and the lower die of the molding die, and a second resin member integrally formed with the resin sealing member, by injecting resin into the resin sealing member forming section through the first resin flowing path and into the second resin flowing path;
• and
• applying bending stress to a first resin member, that is formed integrally with the resin sealing member by the remaining resin in the first resin flowing path, in the widthwise direction of the wiring substrate, thereby producing a crack on the first resin member,
• wherein the first resin flowing path of the molding die has a first portion positioned at the outside of the wiring substrate and a second portion communicating with the first portion and the resin sealing member forming section and positioned over the main surface of the wiring substrate, and
• wherein the height of the second portion of the first resin flowing path and the height of the second resin flowing path from the main surface of the wiring substrate are lower than that of the first portion of the first resin flowing path and that of the resin sealing member forming section.