According to one embodiment, a semiconductor device c includes: a package substrate including a base including a mount portion, and terminals; a semiconductor chip including a first pad to which a ground voltage is supplied, a second pad electrically connected to a first terminal among the terminals, and a semiconductor circuit connected to the first and second pads, the semiconductor chip being provided above the mount portion; and a first capacitor chip including a first capacitor unit provided in a silicon substrate, a first node supplied with the ground voltage, and a second node electrically connected to the second pad, the first capacitor chip being provided above the mount portion.

An antenna device includes an antenna on a substrate, a low-impedance electrostatic discharge (ESD) path for an ESD pulse from the antenna to a ground terminal, and a signal path between the antenna and either a signal terminal or an integrated circuit (IC) die. The ESD and signal paths may each include separate vias through the substrate. A capacitor may couple a signal to or from the antenna and the signal terminal (or IC die) but block low-frequency power (such as an ESD pulse). The ESD path has an electrical length of a quarter of the wavelength and so may present a high impedance to ground for the signal. The antenna device may include or be coupled to an IC die. The IC die may couple to the signal and ground terminals, e.g., opposite the substrate from the antenna.

According to one embodiment, a semiconductor device c includes: a package substrate including a base including a mount portion, and terminals; a semiconductor chip including a first pad to which a ground voltage is supplied, a second pad electrically connected to a first terminal among the terminals, and a semiconductor circuit connected to the first and second pads, the semiconductor chip being provided above the mount portion; and a first capacitor chip including a first capacitor unit provided in a silicon substrate, a first node supplied with the ground voltage, and a second node electrically connected to the second pad, the first capacitor chip being provided above the mount portion.