A quartz crystal oscillator package comprising a quartz crystal vibrator leaf enclosed in an evacuated housing. The vibrator leaf frame is sandwiched and sealed between a pair of housing elements formed by etching at one time the periphery of each housing element and at another time etching a concave portion in each housing element. Opposed concave portions provide the internal volume wherein the vibrator leaf is sealed under vacuum. Using heat and vacuum, a metal film deposited on the sealing surfaces of the housing elements fuses with a binder material to form a eutectic alloy seal. A flat package having small size, high structural strength, an excellent hermetic seal, and high internal vacuum is produced by this method.