according to the first embodiment of the invention, and FIG. 3B is a view of the same package being affixed to the base plate. [0019]FIGS. 4A and 4B are a plan view and a front view of a package for high frequency usages according to a second embodiment of the invention [0020]FIG. 5A is a view of a semiconductor device mounted on a package for high frequency usages according to the second embodime