Quartz-crystal devices and methods for manufacturing same

Abstract

Methods are disclosed for manufacturing quartz-crystal devices. In an exemplary method three wafers are prepared. One is a quartz-crystal wafer defining multiple quartz-crystal pieces; a second is a wafer defining multiple package bases; and a third is a wafer defining multiple lids for the package bases. Each quartz-crystal piece has a respective excitation portion that vibrates when electrically energized and a respective frame portion surrounding the excitation portion. The quartz-crystal wafer has main surfaces that are lapped and polished to mirror-finish them. The base wafer defines multiple package bases each having a floor surface, a bonding surface surrounding the floor surface, and a lower main surface. The lid wafer defines multiple lids each having a ceiling surface, a bonding surface surrounding the ceiling surface, and a upper main surface. The quartz-crystal wafer is sandwiched between the base and lid wafers. The wafers are bonded together by bonding respective main surfaces of the frame portion to respective bonding surfaces. At least two of the upper main surface, lower main surface, floor surface, and ceiling surface are rougher than the surfaces of the excitation portion.