Piezoelectric devices and methods for manufacturing same

Abstract

Devices are disclosed that include a piezoelectric vibrating piece; a glass base and lid form a package enclosing the piezoelectric vibrating piece. The piece has first and second electrodes. The base has first and second opposing surfaces. The base mounts the piezoelectric vibrating piece, and the lid seals the piezoelectric vibrating piece in the package. The base includes first and second metal wires, extending therethrough, whose ends are denuded to the first and second surfaces and connected to the first and second electrodes, respectively. In disclosed methods for making the packaged devices, such as piezoelectric oscillators, multiple packaged devices are made simultaneously by stacking and simultaneously bonding respective wafers on which glass bases, piezoelectric vibrating pieces, and lids have been formed.

1 . A method for manufacturing a piezoelectric device, comprising:
 preparing a lid wafer defining multiple lids connected to the lid wafer;   preparing a piezoelectric wafer defining multiple piezoelectric vibrating pieces connected to the piezoelectric wafer, each piezoelectric vibrating piece comprising at least first and second electrodes;   preparing a glass base wafer defining multiple bases connected to the base wafer, each base comprising a first surface, a second surface, at least first and second metal wires corresponding to the electrodes and extending through a thickness of the base, each wire having respective denuded ends protruding from the first and second surfaces;   placing together the piezoelectric wafer, the lid wafer, and the base wafer to form a wafer sandwich in which the piezoelectric wafer is situated between and registered with the base wafer and the lid wafer, the registration placing the ends of the wires on the first surface of each base in contact with corresponding electrodes of the respective piezoelectric vibrating piece;   bonding together the wafer sandwich to form multiple piezoelectric devices; and   separating each piezoelectric device from the wafer sandwich.   
     
     
         2 . The method of  claim 1 , wherein preparing the glass base wafer comprises:
 for each piezoelectric device to be formed in the wafer sandwich, arranging the respective at least first and second metal wires substantially parallel to each other at designated locations in a mold;   fusing glass fragments at a temperature of 900 C. or less to produce a glass melt;   introducing the glass melt to the mold to form a glass block from the glass melt, the glass block containing the wires embedded therein; and   slicing the glass block substantially perpendicularly to the metal wires to form glass base wafers from the block.   
     
     
         3 . The method of  claim 2 , wherein each of the wires as arranged in the mold is surficially coated with a glass film to provide the wires with enhanced affinity to the glass. 
     
     
         4 . The method of  claim 2 , wherein each of the wires as arranged in the mold has an increased surface roughness to provide the wires with enhanced affinity for the glass. 
     
     
         5 . The method of  claim 1 , wherein preparing the glass base wafer comprises:
 for each piezoelectric device to be formed in the wafer sandwich, arranging the respective at least first and second metal wires substantially parallel to each other at designated locations in a mold;   placing glass fragments in the mold:   fusing the glass fragments in the mold at a temperature of 900 C. or less to form a block of molten glass in the mold, the block containing the wires embedded therein;   allowing the glass block to cool and harden; and   slicing the glass block substantially perpendicularly to the metal wires to form glass base wafers from the block.   
     
     
         6 . The method of  claim 5 , wherein each of the wires as arranged in the mold is surficially coated with a glass film to provide the wires with enhanced affinity to the glass. 
     
     
         7 . The method of  claim 5 , wherein each of the wires as arranged in the mold has an increased surface roughness to provide the wires with enhanced affinity for the glass.