has the shape of a quadrangular plate and is provided with a groove or channel 240 on a bottom surface 234 thereof the second semiconductor die 230 has top and bottom surfaces 232 and 234 respectively and first to fourth outer lateral surfaces 236 a to 236 d the groove 240 extends from the first outer lateral surface 236 a to the second outer lateral surfaces 236 b of the second semiconductor die 230 the first and second outer lateral surfaces 236 a and 236 b are located opposite to each other in order to form the groove 240 the second semiconductor die 230 has openings within first and second outer lateral surfaces 236 a and 236 b a quadrangular inner base surface 242 parallel to the top surface 232 and first and second inner lateral surfaces 244 a and 244 b extending from the opposite sides of the inner base surface 242 to the opposite sides of the bottom surface 234 at a substantially slant angle of 45 u00b0 although a slant angle of 45 u00b0 is shown it would be recognized that the angle may be varied to conform to the geometry of enclosed first die not shown the second semiconductor die 230 is directly bonded onto the top surface 212 of the package substrate 210 so that the first semiconductor die 220 is covered or encapsulated by the groove 240 the groove 240 has the shape of a tunnel which is opened at both ends and preferably has a trapezoidal cross section by performing transfer molding on the first semiconductor die 220 with a molding material 260 an empty space of the groove 240 which is composed of the space between the bottom surface 224 of the first semiconductor die 220 and the top surface.