Package formation method and MEMS package

This invention includes a sacrificial thin film formation step for chemical-mechanical polishing a temporary substrate made of a readily polishable material and sputtering a metal thin film along the smoothly polished surface, and a first bonding step for forming a sealing frame obtained by bringing at least a noble metal on the metal thin film and bonding a substrate on the sealing frame. This invention also includes a temporary substrate removal step for then removing the metal thin film along with the temporary substrate and exposing a new surface at the tip of the sealing frame; and a second bonding step for sputtering a noble metal thin film around a precision machine element on the machine substrate, bringing the new surface of the sealing frame into contact onto the noble metal thin film and bonding the new surface of the sealing frame onto the noble metal thin film at room temperature.