An electronic component manufacturing method, in which a notch and a concave portion are formed in a substrate, includes forming an etching mask in which a maximum width of a first mask portion which forms a width between two side surfaces of the concave portion along a longitudinal direction, when the substrate is seen in a plan view from a direction perpendicular to a surface of the substrate having the concave portion formed therein, is smaller than a width of a second mask portion which forms a minimum width of an opening of the notch, and forming the notch and the concave portion by performing dry etching processing on the substrate.

To realize a resonator element capable of obtaining sufficient electric field efficiency and securing a satisfactory element characteristic, a resonator element of the invention includes a base section and a pair of resonating arms extending from the base section. The resonator element includes recesses having a curved surface shape respectively on two side surfaces (surfaces crossing a direction in which the resonating arms resonate) of the resonating arm.

An object is to provide a frequency adjustment method for a piezoelectric resonator device that is applicable to a microminiaturized device and that can adjust the frequency without deteriorating the accuracy of frequency adjustment. A frequency adjustment method for a tuning-fork quartz resonator is applicable to a tuning-fork quartz resonator that includes a tuning-fork quartz resonator piece having a pair of resonator arms 31, 32 and metallic adjustment films W formed on the resonator arms. The frequency adjustment method adjusts the frequency by reduction of a mass of the metallic adjustment films W. The frequency adjustment method includes: a rough adjustment step for roughly adjusting the frequency by partially thinning or removing the metallic adjustment films W; and a fine adjustment step for finely adjusting the frequency by at least partially thinning or removing products W1, W2 derived from the metallic adjustment film W during the rough adjustment step.

A method of manufacturing a piezoelectric resonator unit that includes preparing a piezoelectric resonator having a piezoelectric element, a pair of excitation electrodes respectively disposed on a first main surface and a second main surface of the piezoelectric element so as to face each other with the piezoelectric element therebetween, and a pair of connection electrodes that are respectively electrically connected to the pair of excitation electrodes; electrically connecting the pair of connection electrodes to a pair of electrode pads on a third main surface of a base member using an electroconductive holding member so as to excitably hold the piezoelectric resonator on the third main surface of the base member; and attaching an electroconductive material, which is scattered from an electroconductive member, to a surface of the electroconductive holding member.

A vibration element includes a base and a vibrating arm extending from the base. The vibrating arm includes an arm positioned between the base and a weight. A weight film is disposed on the weight. The weight has a first principal surface and a second principal surface in a front and back relationship with respect to a center plane of the arm. A center of gravity of the weight is located between the first principal surface and the center plane of the arm. A center of gravity of the weight film is located between the second principal surface and the center plane of the arm.

In a quartz crystal unit, the unit comprising a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines, each of the first and second quartz crystal tuning fork tines having a first vibrational portion including a first width and a second vibrational portion including a second width greater than the first width, at least one groove being formed in at least one of opposite main surfaces of the first vibrational portion of each quartz crystal tuning fork tine, the first width of the first vibrational portion of each quartz crystal tuning fork tine being greater than 0.03 mm and less than 0.075 mm and the second width of the second vibrational portion of each quartz crystal tuning fork tine being greater than 0.04 mm and less than 0.23 mm.

There is provided a method of manufacturing a piezoelectric vibrator element capable of preventing the piezoelectric vibrator element from being damaged when segmentallizing the piezoelectric vibrator element. The method of manufacturing a piezoelectric vibrator element includes the steps of providing the wafer with the piezoelectric plate and a frame part adapted to support the piezoelectric plate via a connection part, providing a pair of excitation electrodes to the piezoelectric plate, and forming a pair of extending electrodes extending from the piezoelectric plate to the frame part through the connection part and electrically connected respectively to the pair of excitation electrodes, and segmentallizing the piezoelectric plate by cutting the connection part. In the step of providing the pair of excitation electrodes, the pair of extending electrodes are formed on a side surface of the connection part.

A method for adjusting a resonant frequency of a resonator without impairing piezoelectricity that includes preparing a lower lid; arranging a substrate with a lower surface that faces the lower lid and forming a first electrode layer, a piezoelectric film, and a second electrode layer on an upper surface of the substrate. Moreover, a vibration arm is formed that bends and vibrates from the first electrode layer, the second electrode layer, and the piezoelectric film and an upper lid faces the lower lid with the resonator interposed therebetween. The method further includes adjusting a frequency of the resonator before or after arranging the upper lid by exciting the vibration arm by applying a voltage between the first electrode layer and the second electrode layer and by causing a part of the vibration arm to collide with either or both of the lower lid and the upper lid.

A method of manufacturing a vibration element includes: manufacturing, by wet etching, a piezoelectric substrate including a vibration element, a frame portion, and a coupling portion that couples the frame portion and the vibration element; and folding the vibration element at the coupling portion and separating the vibration element from the frame portion. In the manufacturing of the piezoelectric substrate by the wet etching, the coupling portion is formed with a first groove portion, and a first protruding portion and a second protruding portion. The first protruding portion has a first outer shape side that defines an outer shape of the coupling portion and a second outer shape side that defines a boundary between the first protruding portion and the first groove portion, and is formed in a shape in which a distance between the first outer shape side and the second outer shape side decreases as a distance from the outer shape side of the vibration element increases. The second protruding portion has a third outer shape side that defines the outer shape of the coupling portion and a fourth outer shape side that defines a boundary between the second protruding portion and the first groove portion, and is formed in a shape in which a distance between the third outer shape side and the fourth outer shape side decreases as a distance from the outer shape side of the vibration element increases.

This piezoelectric wafer has: a piezoelectric vibration piece; a frame portion that supports the piezoelectric vibration piece; and a coupling portion that couples the piezoelectric vibration piece to the frame portion. A pair of first and second metal bumps is formed in juxtaposition on the piezoelectric vibration piece. The coupling portion has slits extending in its width direction except in a bridge, i.e., a part of the coupling portion in its width direction. An end in the width direction of the bridge is distantly spaced from the first and second metal bumps both in a direction perpendicular to the width direction of the coupling portion with no overlap with these metal bumps.