the positioning portions 422 in pillar shape when cross sectionally viewed fig4 illustrates the semiconductor device according to a fourth embodiment of the present invention the semiconductor device 5 illustrated in fig4 is basically the same as that illustrated in fig1 except that the positioning holes 54 in the substrate 50 are formed via conventional etching technique by removing a portion of the first solder mask 504 the core layer 500 and the second solder mask 505 respectively so as to allow the positioning holes 54 to penetrate the substrate 50 further the positioning portions 522 of heat sink 52 are securely positioned within the positioning holes 54 of the substrate 50 by an adhesive 57 allowing the positioning holes 54 to be sealed by the adhesive 57 fig5 illustrates the semiconductor device according to a fifth embodiment of the present invention the semiconductor device 6 illustrated in fig5 is basically the same as that illustrated in fig1 except that in forming the positioning hole 64 a through hole 606 a is formed through the ground pad 606 of the terminal of the first conductive trace 601 formed on the top surface of the core layer 600 the positioning holes 64 are formed by subsequently removing the first.