A heat spreader module includes a base, a heat spreader member arranged on the base, a thermal conductive layer arranged on the heat spreader member, a first joining member interposed between the base and the heat spreader member, and a second joining member interposed between the heat spreader member and the thermal conductive layer. The base comprises a copper alloy which has a proof stress of not less than 45 MPa and a coefficient of thermal conductivity of not less than 270 W/mK after performing a heat treatment between 600.degree. and 900.degree. C. for 10 minutes.