Method for manufacturing semiconductor device

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

• (a) preparing a base material having a main surface, a first side included in the main surface, a second side opposed to the first side included in the main surface, a plurality of first regions extending from the first side toward the second side over the main surface, a plurality of second regions formed between the respective first regions over the main surface, and a plurality of third regions formed between the first side and the second regions;
• (b) after step (a) mounting a semiconductor chip in each of the plurality of second regions of the base material;
• (c) after step (b), covering the first regions and the second regions with one cavity of a molding die and arranging the base material in the molding die such that a plurality of gates is arranged in the third regions;
• and
• (d) after step (c), injecting resin into the cavity from the plurality of gates and forming a sealing resin layer over the main surface of the base material,
• wherein each of the plurality of first regions have groove formed along the first regions, respectively,
• wherein, in a plan view, over a straight line vertically crossing the first side and the second side, one of the second regions and one of the third regions are arranged in a continuously joined manner, and
• wherein, during the step (d), the resin is injected from the first side toward the second side and, in a plan view, the resin is injected such that the vertex of the tip which advances toward the second side most rapidly of the resin supplied into the cavity is located in the second region