US Patent 11158553 Package and semiconductor device

A package includes a base substrate, a frame, and a lead frame. The base substrate is made of metal, and includes a mounting area on which a semiconductor element is to be mounted and a frame area surrounding the mounting area. The frame is provided on the frame area of the base substrate, and includes a first surface facing the frame area and a second surface opposite to the first surface. The lead frame is joined to the second surface of the frame. The frame includes a plurality of dielectric layers having a layered structure and an element connector to be electrically connected to the semiconductor element. The plurality of dielectric layers include a first dielectric layer having first permittivity and a second dielectric layer having second permittivity different from the first permittivity.