A heat transfer member has a heat transfer unit mounted on a mounting sheet. The heat transfer unit comprises a plurality of layers of wire mesh laminated and bonded together and to the mounting sheet. The spaces between the wires of the mesh layers of the heat transfer unit permit liquid to pass through the heat transfer unit so as to conduct heat. A semiconductor element (IC chip) is mounted on the mounting sheet, and to a base. The resulting assembly is immersed in a liquid. Preferably, the planes of the mesh layers are generally perpendicular to the mounting sheet and the semiconductor element and the material of the mounting sheet chosen to have a thermal expansion coefficient between that of the semiconductor element and the heat transfer unit to reduce thermal stresses. The wires of the mesh layers are preferably of copper as this is inexpensive and provides satisfactory heat conduction.