Lsi cooling device

Disclosed is an LSI package cooling heat sink having a heat diffusion plate and thin wire fins joined to the heat diffusion plate. The heat sink is mounted on an LSI package and the LSI package is cooled by the flowing of fluid through the thin wire fins. The wire fins are made of a net formed of longitudinal thin wires intersecting with horizontal thin wires. The net is formed to continuous rectangular shapes or a swirl shape and joined to the heat diffusion plate. The net is constituted so that the number of the thin wires vertical to the heat diffusion plate is larger than the number of the thin wires parallel thereto and the net is joined to the heat diffusion plate by brazing, diffusion joint, pressure welding or the like. Since the heat sink is formed of the net composed of the longitudinal thin wires intersecting with the horizontal thin wires, the irregular portions of the adjacent thin wires are formed at a dislocated position and fluid striking against the thin wires produces many turbulent flows so that a high heat transfer performance can be obtained. Further, since the net formed of the thin wires is used, the size of cooling fins can be reduced and noise can be also lowered. Further, it is possible to produce an LSI package cooling heat sink in a short time which heat sink is excellent in mass-production.