A piezoelectric device includes a piezoelectric vibrating piece and a base. The piezoelectric vibrating piece includes an excitation portion, a framing portion, a connecting portion, excitation electrodes, and extraction electrodes. The base includes a mounting terminal, a cutout portion formed on a side surface, and a cutout-portion electrode formed in the cutout portion. The cutout-portion electrode connects the mounting terminal to the extraction electrode. The extraction electrode includes a cutout-portion region connected to the cutout-portion electrode, an excitation-electrode connecting region connected to the excitation electrode, and an erosion preventing region disposed between the cutout-portion region and the excitation-electrode connecting region to prevent erosion by solder. The extraction electrode in the erosion preventing region is formed without containing gold (Au) and silver (Ag), and the extraction electrodes in the cutout-portion region and the excitation-electrode connecting region are formed containing at least one of gold (Au) and silver (Ag).

A resonator that includes a piezoelectric vibrator, a frame, and a first node generator between the piezoelectric vibrator and the frame. Moreover, a first connecting arm connects the first node generator to the piezoelectric vibrator that opposes the first, and a first holding arm connects the first node generator to a part of the frame that opposes the first node generator. The first node generator includes a width extending in a second direction, which is orthogonal to a first direction of the first connecting arm, that is a maximum width where the first node generator is closer to the first connecting arm than a center of the first node generator relative to the first direction. Moreover, the width of the first node generator gradually decreases from the maximum width as the first node generator extends towards the first holding arm.

Provided is a method for bonding wafers, which can bond the wafers to each other with high reliability while reducing the influence on the wafers. The method for bonding wafers includes the steps of: preparing a first wafer that has, on the surface thereof, a first metal layer with a first rigidity modulus, and a second wafer that has, on the surface thereof, a second metal layer with a second rigidity modulus higher than the first rigidity modulus; removing an oxide film at the surface of the second metal layer while an oxide film at the surface of the first metal layer is not removed; and bonding the surface of the first wafer to the surface of the second wafer.

A resonance device is provided that includes a lower cover; an upper cover coupled to the lower cover; and a resonator that has vibration arms that generate bending vibration in an interior space provided between the lower cover and the upper cover. Moreover, the vibration arms have distal ends provided with metal films on a side that faces the upper cover, and a gap is provided between the distal ends of the vibration arms and the upper cover that is larger than a gap between the distal ends of the vibration arms and the lower cover.

A resonator is provided that includes a vibrating portion including a three or more vibrating arms each having a fixed end and a free end, with at least two of the vibrating arms configured to bend out of plane in different phases, and a base having a front end connected to the fixed end of each vibrating arm and a rear end opposite from the front end. Moreover, a frame is disposed at least partially around the vibrating portion, a holding arm is provided between the vibrating portion and the holding portion and includes a first end connected to the base and a second end connected to the frame, and a plurality of holes disposed in the vibrating portion. Moreover, the plurality of holes are each formed in a region between any one pair of adjacent two of the plurality of vibrating arms in the base portion.

A microelectromechanical resonator includes a support structure, a resonator element suspended to the support structure, and an actuator for exciting the resonator element to a resonance mode. The resonator element includes a plurality of adjacent sub-elements each having a length and a width and a length-to-width aspect ratio of higher than 1 and being adapted to a resonate in a length-extensional, torsional or flexural resonance mode. Further, each of the sub-elements is coupled to at least one other sub-element by one or more connection elements coupled to non-nodal points of the of said resonance modes of the sub-elements for exciting the resonator element into a collective resonance mode.

A resonance device that includes a MEMS substrate that includes a resonator, a top cover having a silicon oxide film on a surface thereof that faces the MEMS substrate, and a bonding part that bonds the MEMS substrate and the top cover to each other so as to seal a vibration space of the resonator. The silicon oxide film includes a through hole that is formed along at least part of the periphery of the vibration space when the top cover is viewed in a plan view and that penetrates to a surface of the top cover. The through hole includes a first metal layer.

A resonator that includes a piezoelectric vibrating portion; a retainer provided in at least part of an area surrounding the piezoelectric vibrating portion; a first node generating portion disposed between the piezoelectric vibrating portion and the retainer; a first connecting arm that connects the first node generating portion to a region in the piezoelectric vibrating portion that faces the first node generating portion; and a first retaining arm that connects the first node generating portion to a region in the retainer that faces the first node generating portion. The first node generating portion is substantially symmetrical with respect to each of two lines passing through a center of the first node generating portion along a first direction and a second direction orthogonal to the first direction, with the first direction being a direction that the first connecting arm connects the first node generating portion to the piezoelectric vibrating portion.

A resonator is provided that includes a base, and three or more vibrating arms each including a first and second electrodes and a piezoelectric film disposed therebetween and having a top surface facing the first electrode. The piezoelectric film vibrates in a predetermined vibration mode when a voltage is applied between the first and second electrodes. Moreover, the three or more vibrating arms include two first arms each located on an outermost side in a direction in which the three or more vibrating arms are arranged and that vibrate in a same phase, and one or more second arms disposed between the two first arms. Each first arm is greater in mass than each second arm.

A resonance device is provided that includes a first substrate with a resonator having an upper electrode, a second substrate that is disposed such that a first surface faces the first substrate with the resonator therebetween, a first terminal that is disposed on a second surface of the second substrate and that is electrically connected to the upper electrode, a second terminal that is disposed on the second surface and that applies a reference electric potential to the resonator, and an extended wiring line that is connected to the first terminal electrically and that extends on the second surface to an outer edge.