A packaging structure for hermetically sealing a functional device by solder connection at a wafer level in which a first Si substrate having a concave portion metallized on its internal surface and a second Si substrate metallized at a position opposed to said concave portion are used, the metallization applied to the internal surface of the concave portion of the first Si substrate and the metallization applied to the second Si substrate at the position opposed to the concave portion are connected by molten solder to hermetically seal the functional device between the first Si substrate and the second Si substrate, whereby the wettability of the solder for the two Si substrates is improved, the bondability between the Si substrates is enhanced, and the yield at which the package is manufactured is improved.