| 摘要 |
PURPOSE:To improve operational efficiency and a yield by forming a non-crystal metal-film layer on a case surface with a metal-film layer formed on its surface and by sealing the case after making it eutectic through a heat treatment. CONSTITUTION:On the sealing part between case 18 and upper case 19, metal films 20 and 21 are formed, on which eutectic material 22 of tin, indium, poly-crystal silicon, or the like is vapor-deposited under vacuum. Lower case 18 with crystal oscillating reed 17 mounted and upper case 19 with eutectic material 22 formed are piled up each other and heated under vacuum to fuse eutectic material 22 and the metal film of gold, silver or the like formed at the sealing part between both upper and lower cases is made eutectic, thereby fulfilling airtight sealing. In this way, since external mechanical force is not applied at the time of airtight sealing, the case will not functure and the high-yield manufacture with good operational efficiency can be done. |
