Semiconductor device

A semiconductor device comprising:

• a first chip including one of a logic circuit and a memory circuit and mounted over a substrate with a circuit surface of the first chip facing up;
• a second chip including the other of the logic circuit and the memory circuit and mounted over the first chip with a circuit surface of the second chip facing down such that the logic circuit and the memory circuit are electrically coupled to each other via a first connection electrode;
• and
• a third chip mounted between the substrate and the second chip with a circuit surface of the third chip facing down and alongside the first chip, the third chip including:
• an interface circuit that converts between a first signal which is input to and output from the logic circuit or memory circuit and a second signal which has a signal speed higher than the first signal and is input to and output from an outside;
• and
• a first through electrode electrically coupling the logic circuit or memory circuit and the interface circuit.