| 主权项 |
1. A substrate comprising:
an insulating substrate; a metal layer formed on a surface of the insulating substrate; and an electronic component soldered to a surface of the metal layer, wherein: the metal layer is made of a metal plate, the surface of the metal layer includes a soldering region and a groove portion that is located on a periphery of the soldering region, the groove portion includes a bottom surface, which is formed of the metal layer, a first side surface, which is located at a side corresponding to the soldering region, and a second side surface, which is located at a side opposite to the soldering region, and a solder spreads from an area between the metal layer and the electronic component and flows into the groove portion to form a soldering fillet spreading from the electronic component to the second side surface of the groove portion. |
