the tubs 8 67 and 80 and heat sink 106 whereby regions other than the regions in which the solder resist is formed result in solder forming regions since the solder resist is also a substance hard to get wet with solder no solder is wet in and spread over the regions in which the solder resist is formed the trenches shown in fig1 a through 19 c may be formed by the solder resist further the lands 43 64 and 85 respectively formed on the printed circuit boards 40 62 and 83 which have been described in the first to fourth embodiments may be formed by patterning the solder resist namely a non separated metal layer is formed in place of the formation of the lands 43 64 and 85 respectively separated on the printed circuit boards 40 62 and 83 and the surface of the metal layer is separated into a plurality of regions by a solder resist whereby a plurality of regions corresponding to the lands referred to above are formed advantageous effects obtained by a typical one of the inventions disclosed in the present application will be described in brief as follows owing to the separation of the other main surface of a tub or heat sink serving as a semiconductor chip loading portion into plural form exposed region i e brazing filler metal solder connecting portions on the other main surface of the semiconductor chip loading portion are represented in plural form and the area of each of the regions is smaller than that of the semiconductor chip loading portion therefore.