Stacked semiconductor device and semiconductor system

A stacked semiconductor device includes a plurality of stacked wiring substrates each having connection electrodes and wires connected to the connection electrodes and each mounted with a semiconductor device, a plurality of conductive via boards each interposed between adjacent two wiring substrates and having an opening for enclosing the semiconductor device, an uppermost wiring substrate formed on the top of the stacked wiring substrates and having wires connected to the connection electrodes, and a lowermost wiring substrate formed under the stacked wiring substrates and having wires connected to the connection electrodes, wherein heat radiation/shield conductive layers are formed on the uppermost and lowermost wiring substrates.