US Patent 6979873 Semiconductor device having multiple substrates

A semiconductor device includes a first substrate including first, second and third layers; and a second substrate including fourth, fifth and sixth layers. The first substrate provides an electric device. The second substrate provides a physical quantity sensor. The first layer of the first substrate and the fourth layer of the second substrate are shields for protecting the electric device and the physical quantity sensor. The device is protected from outside disturbance without adding an additional shield.