The present invention provides an isolation structure for a semiconductor substrate and a method for manufacturing the same, as well as a semiconductor device having the structure. The present invention lowers the temperature of the material having a low dielectric constant and then polishes that material at the lower temperature. The elongated handle has an open end having external threads adjacent to the open end. The heat radiation plate to which the plate-shaped light source is adhered is constituted as a housing casing thus efficiently housing the heat radiation plate. The respective lateral core sections and respective side flaps form therebetween pockets opening inwardly of the pad.