for example cu or au gold the pins 13 are protruding from a first surface of the mother board 2 the first surface of the mother board 2 is a surface opposed to the package substrate 31 first ends upper ends of the pins 13 protrude from the plated through holes 11 leading to the first surface of the mother board 2 and are joined to the solder balls 35 therefore the pins 13 are soldered to the electrode pads 34 by the solder balls 35 second ends lower ends and middle parts of the pins 13 are inserted in the plated through holes 11 the inserted parts of the pins 13 are soldered to the plated through holes 11 by solder 14 embedded in the plated through holes 11 as illustrated in fig3 land patterns 25 are formed on the tops of the plated through holes 12 the land patterns 25 are joined to the solder balls 36 therefore the land patterns 25 are soldered to the electrode pads 34 by the solder balls 36 by performing reflow processing after placing the semiconductor package 3 on the mother board 2 the semiconductor package 3 is mounted on the mother board 2 by performing reflow processing warpage is caused in the mother board 2 and the package substrate 31 as illustrated in fig2 solder balls 35 and 36 are used as joints between the mother board 2 and the package substrate 31 the pins 13 inserted in.