JP6311344B2 - Piezoelectric vibration device - Google Patents

Description

  The present invention relates to a piezoelectric vibration device such as a crystal resonator used in electronic equipment.

  In recent years, the operating frequency of various electronic devices has been increased, and the size of packages has been reduced (especially low profile). For this reason, with the increase in the frequency and the size of the package, the piezoelectric vibration device is required to cope with the increase in the frequency and the size of the package.

  In this type of piezoelectric vibration device, the casing is formed of a rectangular parallelepiped package. This package includes a first sealing member and a second sealing member made of glass or the like, and a piezoelectric vibration plate made of crystal and having excitation electrodes formed on both main surfaces. The first sealing member and the second sealing member The sealing member is laminated via a piezoelectric diaphragm and joined by a metal brazing material, and the excitation electrode of the piezoelectric diaphragm disposed inside the package is hermetically sealed (for example, see Patent Document 1 below) reference). Hereinafter, such a laminated form of piezoelectric vibration devices is referred to as a sandwich structure.

JP2011-30198A

  By the way, in such a sandwich structure piezoelectric vibration device, since the sealing portion and a part of the excitation electrode are connected with the same wiring pattern, when the metal brazing material is heated and melted, the sealing portion It is necessary to prevent the metal brazing material from flowing into the excitation electrode. If the brazing metal flows out from the sealing part to the excitation electrode, not only will the electrical characteristics of the piezoelectric vibration device be disturbed, but the metal brazing material in the sealing part will be insufficient, resulting in a decrease in bonding strength, resulting in poor airtightness. It becomes.

  Therefore, in the piezoelectric vibration device shown in Patent Document 1, a barrier film (such as a metal oxide film) is formed on a conductive path (extraction electrode according to the present invention) that connects a metal film (sealing pattern according to the present invention) and an excitation electrode. A material in which inflow of the metal brazing material is suppressed by forming a metal film in the present invention is disclosed.

  However, even the piezoelectric vibration device disclosed in Patent Document 1 is insufficient to sufficiently suppress the inflow of the metal brazing material. In particular, when a metal brazing material containing tin is used, it is difficult to suppress the diffusion of tin to the excitation electrode even if a blocking film is formed on the upper part of the conductive path where some electrode material exists. . When the excitation electrode is eroded by such a tin diffusion phenomenon, the so-called CI resistance value is deteriorated, and the electrical characteristics of the piezoelectric vibration device are deteriorated. In particular, in a miniaturized piezoelectric vibration device, the excitation electrode is small, and the influence of such diffusion of tin is also great, which may lead to a fatal defect. Further, when forming the metal brazing material on the piezoelectric vibrating device, the electrolytic brazing method electrically connects the sealing portion and the excitation portion electrode, and therefore the metal brazing material cannot be formed only on the sealing portion. The printing / electroless plating technique has a problem in that it is difficult and costly for a small-sized one and a large number of connection terminals such as an oscillator and a complicated electrode pattern.

  Therefore, in order to solve the above-mentioned problems, the present invention supports a more reliable miniaturization of a piezoelectric vibration device having a sandwich structure, which suppresses the outflow of the metal brazing material to the excitation electrode while maintaining hermetic sealing. An object of the present invention is to provide an inexpensive piezoelectric vibration device.

  In the present invention, in order to achieve the above object, a vibration part, a piezoelectric vibration plate in which a sealing part is integrally formed around the vibration part, a sealing part on both main surfaces of the piezoelectric vibration plate, and a metal brazing material are provided. A piezoelectric vibration device comprising a pair of plate-shaped sealing members that are joined and hermetically sealed via each other, each main surface of the piezoelectric vibration plate being provided with an excitation electrode on the vibration portion and on the sealing portion. A sealing pattern and an extraction electrode that draws the excitation electrode into the sealing pattern are formed, and in a portion of the sealing pattern that is close to the extraction electrode, a part of the sealing pattern is separated from the sealing pattern. A separated floating island pattern is formed, and a dividing portion is formed between the floating island pattern and the extraction electrode inside the sealing portion, and the upper portion of the dividing portion has wettability with the metal brazing material. With a low metal film, the floating island pattern and the extraction electrode Each sealing member is formed with a sealing-side sealing pattern for joining with the sealing pattern of the piezoelectric diaphragm, and the sealing-side sealing pattern of each sealing member; The sealing pattern and floating island pattern of each main surface of the piezoelectric diaphragm are joined with a metal brazing material, and the excitation electrodes are led out to the outside through the sealing side sealing patterns or the sealing patterns, respectively. A part of the connection path is configured.

  With the above configuration, the metal film having low wettability with the metal brazing material on the upper part of the dividing portion where no electrode is formed in the connection path from the extraction electrode of each excitation electrode to each sealing pattern on both main surfaces of the piezoelectric diaphragm And floating island patterns spaced apart from the sealing pattern are interposed. For this reason, between the sealing pattern and the floating island pattern, the molten metal brazing material cannot directly flow out from the sealing pattern of the piezoelectric diaphragm, and the sealing side sealing pattern of the facing sealing portion is interposed. Only molten metal brazing material can flow out. Accordingly, the flow of molten metal brazing material can be suppressed while being delayed, and the amount of flow can be limited to only the metal brazing material that is in direct contact with the floating island pattern, so that the overall flow amount can be reduced. . That is, it is possible to reduce the absolute amount of flowing out while suppressing the flowing out of the metallic brazing material from the sealing pattern to the floating island pattern before the joining of the metallic brazing material is completed.

  In addition, as described above, the metal brazing material that has flowed out of the floating island pattern in a state where the absolute amount of the metal brazing material flowing out can be reliably damped by the metal film having low wettability with the metal brazing material. Specifically, since no electrode is formed by the dividing portion and there is no connection path other than the metal film having low wettability with the metal brazing material on the upper part, the metal brazing material is directed toward the extraction electrode of the excitation electrode. Not only will it not flow out, but the components of the metal brazing material will not diffuse at all toward the extraction electrode of the excitation electrode.

  As described above, by combining the constituent elements of the sealing film, the floating island pattern, and the metal film having low wettability with the metal brazing material, the flow of the metal brazing material and its components It can be set as the structure effective in suppressing spreading | diffusion.

  In addition, after finally joining with the metal brazing material, each excitation electrode of the piezoelectric diaphragm is utilized by utilizing the sealing side sealing pattern of each sealing member or the sealing pattern of both main surfaces of the piezoelectric diaphragm. Can be effectively formed in a space-saving state corresponding to downsizing.

  The metal brazing material may be an alloy containing tin. In this configuration, in addition to the above-described effects, a low-melting-point metal brazing material can be configured, so that thermal adverse effects on the piezoelectric vibration device can be suppressed as much as possible, and the tin component of the metal brazing material can be used as the excitation electrode. Will not spread.

  Further, an alloy film containing tin may be formed on the uppermost layer of the sealing portion of the piezoelectric diaphragm by electrolytic plating. In this configuration, since there is a floating island pattern separated from the sealing pattern in addition to the above-described effects, the electrode pattern is an inexpensive and miniaturized and complicated electrode pattern by electrolytic plating of a tin-containing alloy film. In addition, the metal brazing material can be easily formed only on the sealing pattern of the piezoelectric diaphragm. In addition, the alloy film is formed on the excitation electrode, and the electrical characteristics are not adversely affected. Also, by forming the alloy film only on the sealing pattern formed on both main surfaces of the piezoelectric diaphragm, the alloy film for sealing can be formed at once by only one plating process. .

In the piezoelectric vibration device having a sandwich structure, it is possible to provide an inexpensive piezoelectric vibration device corresponding to a more reliable miniaturization that suppresses the outflow of the metal brazing material to the excitation electrode while maintaining hermetic sealing.

FIG. 1 is a schematic configuration diagram showing each configuration of the crystal resonator according to the present embodiment. FIG. 2 is a schematic plan view of the first sealing member of the crystal resonator according to the present embodiment. FIG. 3 is a schematic back view of the first sealing member of the crystal resonator according to the present embodiment. FIG. 4 is a schematic plan view of the crystal diaphragm of the crystal resonator according to the present embodiment. FIG. 5 is a schematic back view of the crystal diaphragm of the crystal resonator according to the present embodiment. FIG. 6 is a schematic plan view of the second sealing member of the crystal resonator according to the present embodiment. FIG. 7 is a schematic back view of the second sealing member of the crystal resonator according to the present embodiment. FIG. 8 is a cross-sectional view taken along the line AA in a state where the constituent members of FIGS. 2 to 7 are assembled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment described below, a case is shown in which the present invention is applied to a surface-mounted crystal resonator as a piezoelectric vibration device that performs piezoelectric vibration.

  In the crystal resonator 101 according to the present embodiment, as shown in FIG. 1, a crystal diaphragm 2 (a piezoelectric diaphragm in the present invention) and a first excitation electrode 221 (see FIG. 4) of the crystal diaphragm 2 are provided. A first sealing member 3 that hermetically seals the first excitation electrode 221 formed on one main surface 211 of the crystal diaphragm 2 and the other main surface 212 of the crystal diaphragm 2 A second sealing member 4 that covers the second excitation electrode 222 (see FIG. 5) and hermetically seals the second excitation electrode 222 formed in a pair with the first excitation electrode 221 is provided.

  In the crystal resonator 101, the crystal diaphragm 2 and the first sealing member 3 are joined, and the crystal diaphragm 2 and the second sealing member 4 are joined to form a sandwich-structured package 12. And the 1st sealing member 3 and the 2nd sealing member 4 are joined via the crystal diaphragm 2, and the internal space 13 of the package 12 is formed, In this internal space 13 of this package 12, crystal | crystallization The vibration part 23 including the first excitation electrode 221 and the second excitation electrode 222 formed on both main surfaces 211 and 212 of the diaphragm 2 is hermetically sealed. As shown in FIG. 1, the internal space 13 is biased to one end side (left side in plan view) of the package 12 in plan view.

  The crystal resonator 101 according to the present embodiment has a package size of 1.0 × 0.8 mm, and is intended to be reduced in size and height. In addition, with the miniaturization, the package 12 does not form a castellation and uses the through holes (see the first through hole 261, the second through hole 441, and the third through hole 442) to conduct the electrodes. ing.

  Next, each configuration of the above-described crystal resonator 101 will be described with reference to FIGS. Here, each member configured as a single unit in which the crystal diaphragm 2, the first sealing member 3, and the second sealing member 4 are not joined will be described.

  As shown in FIGS. 4 and 5, the quartz diaphragm 2 is made of quartz that is a piezoelectric material.

  In addition, a pair of (paired) excitation electrodes (a first excitation electrode 221 and a second excitation electrode 222) are formed on both main surfaces 211 and 212 (one main surface 211 and another main surface 212) of the crystal diaphragm 2. ing. The two main surfaces 211 and 212 are formed with two notches 24 (penetrating shape) so as to surround the pair of first excitation electrodes 221 and second excitation electrodes 222, thereby constituting the vibration part 23. .

  In this crystal diaphragm 2, the first sealing member 3 and the second sealing member 4 are bonded to the outside along the vibration part 23 of both main surfaces 211 and 212 so as to surround the vibration part 23. The vibration side sealing part 25 (frame part) is provided in the upper part of the frame part 26, respectively. As shown in FIGS. 4 and 5, the vibration-side sealing portion 25 is located biased to the left of the two main surfaces 211 and 212 in plan view.

  The cutout 24 includes a concave body 241 in plan view (three rectangles in plan view, each of which is formed by extending two rectangles from both ends of one rectangle in plan view in a direction perpendicular to the longitudinal direction of the rectangle). A planar view body) and a rectangular body 242 in plan view, and a frame in which the vibration part 23 and the vibration side sealing part 25 are formed between the concave body 241 in plan view and the rectangular body 242 in plan view. Bridge portions 271 and 272 connecting the portion 26 are formed.

  A vibration side first bonding pattern 251 (first sealing pattern) for bonding to the first sealing member 3 is provided in the vibration side sealing portion 25 of the frame portion 26 of the one main surface 211 of the crystal diaphragm 2. The vibration-side second bonding pattern 252 (second sealing) for bonding to the second sealing member 4 is formed on the vibration-side sealing portion 25 of the frame portion 26 of the other main surface 212 of the crystal diaphragm 2. Pattern) is formed.

  The internal space 13 is formed inside (inside) the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252.

  With respect to these electrode patterns, the first extraction electrode 223 extracted from the first excitation electrode 221 to a position close to the bridge portion 271 and the portion of the vibration side first bonding pattern 251 adjacent to the bridge portion 271 (vibrator) In the side bonding pattern 251, a portion close to the first extraction electrode 223), a first narrow portion 2513 having a narrow width of a part of the vibration side first bonding pattern 251 is formed and adjacent to the first narrow portion 2513. Thus, a first floating island pattern 253 is formed in which a part of the vibration side first bonding pattern 251 is separated from the vibration side first bonding pattern 251 and protrudes toward the bridge portion 271. At the position of the bridge portion 271, a first dividing portion 255 is formed between the first extraction electrode 223 and the first floating island pattern 253, and the upper end of the first floating island pattern 253 is above the first dividing portion 255. A first metal film 257 having a low wettability with a sealing material 11 made of a metal brazing material, which will be described later, is formed while connecting a part of the part and a part of the upper end of the first extraction electrode 223. Note that the first floating island pattern 253, the first dividing portion 255, and the first metal film 257, which are the final flow prevention portions of the metal brazing material, are located near the frame portion 26 in the bridge portion 271 or the frame portion 26. It is desirable to form only in the position. By comprising in this way, the bad influence to the vibration part 23 by the metal brazing material which flowed out is further reduced.

  In addition, the second extraction electrode 224 drawn out from the second excitation electrode 222 to a position close to the bridge portion 272 and a portion of the vibration side second bonding pattern 252 that is close to the bridge portion 272 (the vibrator side bonding pattern 252). In the portion adjacent to the second extraction electrode 224), a second narrow portion 2523 having a narrow width of a part of the vibration side second bonding pattern 252 is formed, and the vibration side is adjacent to the second narrow portion 2523. A second floating island pattern 254 is formed in which a part of the second bonding pattern 252 is separated from the vibration-side second bonding pattern 252 and protrudes toward the bridge portion 272. At the position of the bridge portion 272, a second dividing portion 256 is formed between the second extraction electrode 224 and the second floating island pattern 254, and the upper end of the second floating island pattern 254 is above the second dividing portion 256. A second metal film 258 having a low wettability with a sealing material 11 made of a metal brazing material, which will be described later, is formed while connecting a part of the part and a part of the upper end of the second extraction electrode 224. Note that the second floating island pattern 254, the second dividing portion 256, and the second metal film 258, which are the final flow prevention portions of the metal brazing material, are located near the frame portion 26 in the bridge portion 272 or the frame portion 26. It is desirable to form only in the position. By comprising in this way, the bad influence to the vibration part 23 by the metal brazing material which flowed out is further reduced.

  With the electrode pattern configuration described above, the vibration-side first bonding pattern 251 and the first excitation electrode 221 on the one main surface 211 of the crystal diaphragm 2 are the first between the first narrow portion 2513 and the first floating island pattern 253. A conductive path including the first floating island pattern 253, the first metal film 257, and the extraction electrode 223 is formed at a place other than the 1 gap portion 2514, and the vibration side second bonding pattern 252 on the other main surface 212 of the crystal diaphragm 2 The second excitation electrode 222 is a portion other than the second gap portion 2524 between the second narrow portion 2523 and the second floating island pattern 254, and from the second floating island pattern 254, the second metal film 258, and the extraction electrode 224. A conduction path is formed.

  In addition, the conduction | electrical_connection interruption | blocking part in the 1st gap part 2514 is the vibration side 1st joining pattern 251 and the 1st floating island pattern 253 of the quartz-crystal diaphragm 2, and the sealing side 1st joining pattern 321 of the 1st sealing member 3 mentioned later. Are bonded to each other through a bonding material 11 made of a metal brazing material, which will be described later, and the crystal diaphragm 2 and the first sealing member 3 are bonded together and sealed, thereby sealing the vibrator-side first bonding pattern 251 and sealing. Conduction is made through the first side bonding pattern 321. The conduction cut-off portion in the second gap portion 2524 includes a vibration-side second bonding pattern 252 and a second floating island pattern 254 of the crystal diaphragm 2 and a sealing-side second bonding pattern 421 of the second sealing member 4 described later. The vibrator-side second bonding pattern 252 and the sealing-side second bonding pattern 421 are bonded by bonding through the bonding material 11 to be bonded, and bonding the crystal diaphragm 2 and the second sealing member 4 together. Through. Thus, a conduction path from the first excitation electrode 221 to the vibration side first bonding pattern 251 and a conduction path from the second excitation electrode 222 to the vibration side second bonding pattern 252 are ensured. Finally, the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 are bonded to the external circuit board formed on the other main surface side 412 that does not face the piezoelectric vibration plate of the second sealing member 4. The external electrode terminals (one external electrode terminal 431 and the other external electrode terminal 432) are electrically connected.

  The vibration-side first bonding pattern 251 includes a base PVD film 2511 formed by physical vapor deposition on one main surface 211 and an electrode PVD formed by physical vapor deposition on the base PVD film 2511 and stacked. Similarly, the vibration-side second bonding pattern 252 includes a base PVD film 2521 formed by physical vapor deposition on the other main surface 212, and a physical vapor phase on the base PVD film 2521. The electrode PVD film 2522 is formed by being grown and laminated. That is, the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 have the same configuration, and a plurality of layers are stacked on the vibration side sealing portion 25 of both main surfaces 211 and 212, A Cr layer and an Au layer are formed by vapor deposition from the lowermost layer side. Thus, in the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252, the underlying PVD films 2511 and 2521 are made of a single material (Cr), and the electrode PVD films 2512 and 2522 are a single material. The electrode PVD films 2512 and 2522 are made of (Au) and are thicker than the underlying PVD films 2511 and 2521.

  In addition, the first excitation electrode 221, the first extraction electrode 223, the first floating island pattern 253, and the vibration-side first bonding pattern 251 formed on the main surface 211 of the crystal diaphragm 2 have the same thickness, and the first excitation The surface (main surface) of the electrode 221, the first extraction electrode 223, the first floating island pattern 253, and the vibration side first bonding pattern 251 is composed of the first PVD film group for vibrators of the same metal. The second excitation electrode 222, the second extraction electrode 224, the second floating island pattern 254, and the vibration side second bonding pattern 252 formed on the other main surface 212 of the crystal diaphragm 2 have the same thickness, and the second excitation electrode 222, the second extraction electrode 224, the second floating island pattern 254, and the surface (main surface) of the vibration-side second bonding pattern 252 are made of the second PVD film group for vibrators of the same metal.

  In addition, the first metal film 257 formed on one main surface 211 of the crystal diaphragm 2 and the second metal film 258 formed on the other main surface 212 are formed of a sealing material 11 made of a gold-tin brazing material, which will be described later. A part of the pattern after forming the first PVD film group for the vibrator and the second PVD film group for the vibrator, and the PVD film made of only a single material (Cr single layer) having low wettability. And is formed so as to overlap the upper part of the electrode.

  The vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 are non-Sn patterns.

  In addition, as shown in FIGS. 4 and 5, a first through hole 261 is formed in the crystal diaphragm 2, and the vibration side first joining pattern connected to the first excitation electrode 221 through the first through hole 261. 251 is drawn to the other main surface 212 side. The first through-hole 261 is arranged outside the internal space 13 and is located on the other end side in plan view (right side in plan view) of both the main surfaces 211 and 212 as shown in FIG. 261 is not formed inside the internal space 13. Here, the inside of the internal space 13 means strictly the inside of the inner peripheral surface of the bonding material 11 without including the bonding material 11.

The first sealing member 3 is made of a material having a bending rigidity (secondary moment of section × Young's modulus) of 1000 [N · mm ² ] or less. Specifically, as shown in FIGS. 2 and 3, the first sealing member 3 is a rectangular parallelepiped substrate formed from a single glass wafer, and the other main surface 312 ( The surface to be bonded to the quartz diaphragm 2 is formed as a flat and smooth surface.

  The other main surface 312 of the first sealing member 3 is provided with a sealing-side first sealing portion 32 for joining to the crystal diaphragm 2. As shown in FIG. 3, the sealing-side first sealing portion 32 is biased to the left of the other main surface 312 of the first sealing member 3 in plan view.

  A sealing-side first bonding pattern 321 for bonding to the crystal diaphragm 2 is formed on the sealing-side first sealing portion 32 of the first sealing member 3. The sealing side first bonding pattern 321 has the same width at all positions on the sealing side first sealing portion 32 of the first sealing member 3.

  The sealing-side first bonding pattern 321 is formed by stacking a base PVD film 3211 formed by physical vapor deposition on the first sealing member 3 and a physical vapor deposition on the base PVD film 3211. Electrode PVD film 3212 formed. In this embodiment mode, Cr is used for the base PVD film 3211 and Au is used for the electrode PVD film 3212. Moreover, the sealing side 1st joining pattern 321 is a non-Sn pattern. Specifically, the sealing-side first bonding pattern 321 is configured by laminating a plurality of layers on the sealing-side first sealing portion 32 of the other main surface 312, and from the lowermost layer side, a Cr layer and Au A layer is formed by vapor deposition.

For the second sealing member 4, a material having a bending rigidity (secondary moment of section × Young's modulus) of 1000 [N · mm ² ] or less is used. Specifically, as shown in FIG. 6, the second sealing member 4 is a rectangular parallelepiped substrate formed from a single glass wafer, and one main surface 411 (quartz crystal vibration) of the second sealing member 4 The surface to be joined to the plate 2) is formed as a flat smooth surface.
The main surface 411 of the second sealing member 4 is provided with a sealing-side second sealing portion 42 for joining to the crystal diaphragm 2. As shown in FIG. 6, the sealing-side second sealing portion 42 is located biased to the left of the main surface 411 of the second sealing member 4 in plan view.

  In addition, a pair of external electrode terminals (one external electrode terminal 431, etc.) electrically connected to the outside are provided on the other main surface 412 of the second sealing member 4 (an outer main surface not facing the crystal diaphragm 2). An external electrode terminal 432) is provided. One external electrode terminal 431 is electrically connected directly to the first excitation electrode 221 via the vibration side first bonding pattern 251, and the other external electrode terminal 432 is second excited via the vibration side second bonding pattern 252. It is electrically connected directly to the electrode 222. As shown in FIG. 7, the one external electrode terminal 431 and the other external electrode terminal 432 are respectively located at both ends in the longitudinal direction of the other main surface 412 of the second sealing member 4 in the plan view. The pair of external electrode terminals (one external electrode terminal 431 and the other external electrode terminal 432) are formed of a base PVD film 4311 and 4321 formed by physical vapor deposition on the other main surface 412, and a base PVD film 4311, The electrode PVD films 4312 and 4322 are formed by physical vapor deposition on 4321 and are stacked. In addition, the underlying PVD films 2511, 2521, 3211, and 4211 of the vibration side first bonding pattern 251, the vibration side second bonding pattern 252, the sealing side first bonding pattern 321, and the sealing side second bonding pattern 421 described above. The base PVD films 4311 and 4321 of the external electrode terminals (one external electrode terminal 431 and the other external electrode terminal 432) are thicker than the thickness of the external PV terminal. Further, the one external electrode terminal 431 and the other external electrode terminal 432 occupy a region of 1/3 or more of the other main surface 412 of the second sealing member 4.

  In addition, a sealing-side second bonding pattern 421 for bonding to the crystal diaphragm 2 is formed on the sealing-side second sealing portion 42 of the second sealing member 4. The sealing side second bonding pattern 421 has the same width at all positions on the sealing side second sealing portion 42 of the second sealing member 4.

  The sealing-side second bonding pattern 421 is formed by stacking a base PVD film 4211 formed by physical vapor deposition on the second sealing member 4 and a physical vapor deposition on the base PVD film 4211. The electrode PVD film 4212 is formed. Note that in this embodiment mode, Cr is used for the base PVD film 4211 and Au is used for the electrode PVD film 4212. Further, the sealing-side second bonding pattern 421 is a non-Sn pattern. Specifically, the sealing-side second bonding pattern 421 is configured by laminating a plurality of layers on the sealing-side second sealing portion 42 of the other main surface 412, and from the lowermost layer side, a Cr layer and Au The layers are formed by physical vapor deposition (evaporation, sputtering, etc.).

  The second sealing member 4 is formed with two through holes (a second through hole 441 and a third through hole 442) as shown in FIGS. The second through-hole 441 and the third through-hole 442 are disposed outside the internal space 13, and the second through-hole 441 has both main surfaces (one main surface 411, another main surface 412 as shown in FIGS. 6 and 7). The third through hole 442 is located on the upper left side in the plan view, and the second through hole 441 and the third through hole 442 are not formed inside the internal space 13. Here, the inside of the internal space 13 means strictly the inside of the inner peripheral surface of the bonding material 11 without including the bonding material 11. Then, the vibration-side first bonding pattern 251 and the other external electrode terminal 432 connected to the first excitation electrode 221 of the crystal vibration plate 2 through the first through hole 261 and the second through hole 441 of the crystal vibration plate 2 Conducted. The vibration side second bonding pattern 252 connected to the second excitation electrode 222 of the crystal diaphragm 2 is electrically connected to the other external electrode terminal 432 through the second through hole 441 and the sealing side second bonding pattern 421.

  In the crystal resonator 101 having the above-described configuration, the bonding material 11 made of a metal brazing material such as gold tin is used, and the crystal vibrating plate 2 and the first sealing member 3 are connected to the vibration side first bonding pattern 251 and the sealing side first. The crystal bonding plate 321 and the second sealing member 4 are bonded together with the vibration-side second bonding pattern 252 and the sealing-side second bonding pattern 421 being stacked. Thus, the package 12 having the sandwich structure shown in FIG. 1 is manufactured.

  For the bonding material 11 made of the above-mentioned metal brazing material such as gold tin, as shown in FIGS. 4 and 5, the most of the vibrator side sealing patterns 251 and 252 (sealing portions) of the crystal diaphragm 2 are used. A gold-tin alloy film M is previously formed on the upper layer by electrolytic plating. In this configuration, the first floating island pattern 253 spaced from the vibration side first bonding pattern 251 and the second floating island pattern 254 spaced from the vibration side second bonding pattern 252 exist on both main surfaces, respectively. Even if the gold-tin alloy film is formed by the technique, the gold-tin alloy film (metal brazing material) can be formed only on the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252, and the first excitation electrode 221 is formed. In addition, the gold-tin alloy film is formed on the second excitation electrode 222, and the electrical characteristics are not adversely affected. Further, by forming a gold-tin alloy film only on the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 on both main surfaces of the quartz crystal vibrating plate 2, it is possible to perform sealing only by a single plating process. The said gold tin alloy film can be formed in a lump. However, not limited to the present embodiment, only the sealing-side first bonding pattern 321 of the first sealing member 3 and the sealing-side second bonding pattern 421 of the second sealing member 4, or the vibrator of the crystal diaphragm 2 In combination with the side sealing patterns 251 and 252 (sealing portions), a gold tin alloy film may be electroplated on the uppermost layer.

  According to the present embodiment, each sealing pattern is formed from the extraction electrodes (the first extraction electrode 223 and the second extraction electrode 224) of the respective excitation electrodes on both main surfaces (one main surface 211 and the other main surface 212) of the crystal diaphragm 2. In the connection path to the (vibration side first joining pattern 251 and the vibration side second joining pattern 252), the gold tin brazing on the upper part of each dividing part (first dividing part 255 and second dividing part 256) where no electrode is formed. Cr single layer metal film (first metal film 257 and second metal film 258) having low wettability with the material (encapsulant 11), and floating island patterns (first floating island pattern 253 and second floating island pattern 254), Are intervening.

  For this reason, between the sealing patterns and the floating island patterns, the gold-tin brazing material (sealing material 11) that has directly melted from the sealing patterns of the quartz crystal diaphragm cannot flow out, and the sealing facing each other. It melted only through the sealing-side sealing patterns (sealing-side first bonding pattern 321 and sealing-side second bonding pattern 421) of the stopper members (first sealing member 3 and second sealing member 4). A gold-tin brazing material (sealing material 11) can flow out.

  Accordingly, the flow of molten gold-tin brazing material (encapsulant 11) can be suppressed while being delayed, and the amount of flow is also in direct contact with the floating island patterns (first floating island pattern 253 and second floating island pattern 254). Since only the gold-tin brazing material (sealing material 11) can be used, the flow-out amount as a whole can be reduced. That is, before the joining of the gold-tin brazing material (sealing material 11) is completed, the floating island pattern (first floating island pattern 253) from each sealing pattern (vibration side first joint pattern 251 and vibration side second joint pattern 252). And the absolute amount of the flow-out can be reduced while suppressing the flow-out of the gold-tin brazing material (sealing material 11) to flow out to the second floating island pattern 254).

  Further, as described above, the gold-tin brazing material (the first floating island pattern 253 and the second floating island pattern 254) that flows out from the floating island pattern in a state where the absolute amount of the flow of the gold-tin brazing material (sealing material 11) is small ( Further, the sealing material 11) can be reliably damped by a Cr single layer metal film (first metal film 257 and second metal film 258) having low wettability with the gold-tin brazing material (sealing material 11). . Specifically, an electrode is not formed by each divided part (the first divided part 255 and the second divided part 256), and a Cr single layer having low wettability with the gold tin brazing material (sealing material 11) on the upper part thereof. Since there is no connection path other than the metal films (the first metal film 257 and the second metal film 258), the gold tin solder is directed toward the excitation electrodes (the first extraction electrode 223 and the second extraction electrode 224). Not only the material (sealing material 11) does not flow out, but also the tin component of the gold-tin brazing material (sealing material 11) is the extraction electrode of the excitation electrode (first extraction electrode 223 and second extraction electrode 224). There is no longer any diffusion.

  As described above, each sealing pattern (vibration side first joining pattern 251 and vibration side second joining pattern 252), floating island pattern (first floating island pattern 253 and second floating island pattern 254), and gold-tin brazing material (sealing) By combining the respective constituent elements of the Cr single layer metal film (the first metal film 257 and the second metal film 258) with low wettability with the stopper material 11), the gold-tin brazing material can be drastically compared with the conventional one. It can be set as the structure effective in suppressing the outflow of the (sealing material 11), and the spreading | diffusion of the tin component.

  Moreover, after finally joining with the gold tin brazing material (sealing material 11), the sealing side sealing pattern (sealing) of each sealing member (the first sealing member 3 and the second sealing member 4). Stop side first bonding pattern 321 and sealing side second bonding pattern 421) or sealing patterns (vibration side first bonding pattern 251 and vibration side second bonding pattern 252) on both main surfaces of the quartz crystal diaphragm 2 are utilized. Then, one connection path for leading each excitation electrode (first excitation electrode 221 and second excitation electrode 222) of the crystal diaphragm 2 to each external electrode terminal (one external electrode terminal 431, another external electrode terminal 432). The portion can be effectively formed in a space-saving state corresponding to miniaturization.

  Further, in the manufacturing process, the first extraction electrode 223, the second extraction electrode 224, the vibration side first bonding pattern 251, and the vibration side first before the heat-melt bonding of the gold-tin brazing material (sealing material 11) are performed. The two-joint pattern 252 is not electrically connected. As a result, various inspections for only the excitation electrodes (first excitation electrode 221 and second excitation electrode 222) can be performed in the inspection process for performing vibration inspection, and the degree of freedom of vibration inspection is increased.

  Moreover, in the package 12 manufactured here, as shown in FIGS. 1-7, the internal space 13 is located on the left side in plan view. Further, the sealing side first bonding pattern 321 formed on the first sealing member 3 and the sealing side second bonding pattern 421 formed on the second sealing member 4 do not overlap in plan view. Specifically, the planar view area in the sealing-side first bonding pattern 321 is wider than the planar view area in the sealing-side second bonding pattern 421. In the present embodiment, the planar view area in the sealing-side first bonding pattern 321 is wider than the planar view area in the sealing-side second bonding pattern 421, but the present invention is not limited to this. The planar view region in the stop-side second joining pattern 421 may be wider than the planar view region in the sealing-side first joining pattern 321. However, since one external electrode terminal 431 and another external electrode terminal 432 are formed on the second sealing member, the planar view region in the sealing side first bonding pattern 321 is the sealing side second bonding pattern 421. The wiring pattern can be easily routed (conducting a conduction path), and the wiring pattern routing area (conduction ensuring area) can be increased.

  In addition, compared with the vibration-side first bonding pattern 251 and the vibration-side second bonding pattern 252 formed on the crystal diaphragm 2, the sealing-side first bonding pattern 321 formed on the first sealing member 3 and the first 2 The sealing-side second bonding pattern 421 formed on the sealing member 4 is wide.

  Moreover, since the through-hole (2nd through-hole 441, 3rd through-hole 442) distribute | arranged to the outer side of the internal space 13 is formed in the 2nd sealing member 4, the 2nd through-hole 441, the 3rd through-hole The second through hole 441 and the third through hole 442 are compared with the configuration in which the second through hole 441 and the third through hole 442 are arranged inward of the internal space 13 without the influence of the 442 affecting the internal space 13. Airtight defects caused by can be avoided.

  Further, unlike the present embodiment, when the through hole is arranged in the internal space, it is necessary to ensure the airtightness of the internal space, and a process of filling the through hole in the internal space with a metal or the like is required. On the other hand, according to the present embodiment, since the through holes (second through hole 441 and third through hole 442) are formed outside the internal space 13, the vibration side first bonding pattern 251 and the vibration are vibrated. The wiring pattern can be routed in the same process as the pattern formation of the second side bonding pattern 252, the sealing side first bonding pattern 321, and the sealing side second bonding pattern 421, and the manufacturing cost can be reduced.

  Moreover, since the internal space 13 is located biased to one end side in plan view (left side in plan view), a through hole (second through hole) is formed on the other end side in plan view (right side in plan view). The hole 441) and the electrode pattern can be easily formed, and the electrode pattern that affects the first excitation electrode 221 and the second excitation electrode 222 disposed in the internal space 13 can be easily formed. Furthermore, the arrangement of through holes (second through hole 441 and third through hole 442) that affect the hermetic sealing of the internal space 13 can be facilitated.

  Further, the first sealing member 3 is formed with a sealing-side first bonding pattern 321 having the same width at all positions, and the second sealing member 4 is sealed with the same width at all positions. The side second bonding pattern 421 is formed, and through holes (second through holes 441 and third through holes 442) arranged outside the internal space 13 are formed in the second sealing member 4. It is possible to suppress the flow of the bonding material 11 to the wider pattern width due to the different widths of the patterns, and as a result, the first sealing member 3 and the second sealing member 4 are bonded to the crystal diaphragm 2. The state can be stabilized. Furthermore, since a through hole (second through hole 441, third through hole 442) disposed outside the internal space 13 is formed in the second sealing member 4, the through hole (second through hole 441, first through hole 441, As compared with the configuration in which the through holes (second through hole 441 and third through hole 442) are arranged inward of the internal space 13 without the influence of the three through holes 442) reaching the internal space 13. Airtight defects caused by the second through hole 441 and the third through hole 442) can be avoided.

  In the present embodiment, glass is used for the first sealing member 3 and the second sealing member 4, but is not limited to this, and other brittle materials such as quartz may be used.

  In this embodiment, quartz is used for the piezoelectric diaphragm, but the present invention is not limited to this, and other materials may be used as long as they are piezoelectric materials, such as lithium niobate, lithium tantalate, etc. It may be.

  Further, in the present embodiment, a gold-tin metal brazing material is used as the bonding material 11, but the present invention is not limited to this, and is composed of a tin-based metal brazing material containing other materials. May be. Since such a metal brazing material can have a low melting point, it is possible to suppress thermal adverse effects on the piezoelectric vibration device as much as possible.

  In the present embodiment, a dividing portion (255, 256) is formed between the extraction electrode (223, 224) and the floating island pattern (253, 254), and an upper end portion of the floating island pattern is formed above the dividing portion. By forming a metal film (257, 258) having low wettability with a sealing material 11 made of a metal brazing material that connects a part of the lead electrode and a part of the upper end of the extraction electrode, a sealing made of a metal brazing material is formed. This is a flow prevention portion of the stopper 11. Not only this configuration, but only a partial region of the lead electrode (223, 224) is configured as only a Cr single layer base electrode with low wettability, and the exposed portion of the base electrode flows in the sealing material 11 It is good also as a prevention part. Further, the metal film (257, 258) having low wettability with a metal brazing material such as gold tin is not limited to Cr but may be Ti or the like, as long as it is a preferable material particularly for preventing the diffusion of tin. It may be a material.

  In the present embodiment, the vibration side first bonding pattern 251, the vibration side second bonding pattern 252, the sealing side first bonding pattern 321, and the sealing side second bonding pattern 421 include Cr and Au. However, it is not limited to this, and Cu (Cu simple substance or Cu alloy) may be included. In this case, when Cu (Cu simple substance or Cu alloy) is included, it is due to the occurrence of external force such as dropping during production (when joining, impact due to the occurrence of external force such as pressurization) or during use. It can contribute to stress relaxation during impact and solder mounting. That is, the mechanical strength is improved by including Cu in the vibration side first bonding pattern 251, the vibration side second bonding pattern 252, the sealing side first bonding pattern 321, and the sealing side second bonding pattern 421.

  Further, when Cr is used for the underlying PVD films 2511, 2521, 3211, and 4211, Cr diffuses into the electrode PVD films 2512, 2522, 3212, and 4212, and Cu is diffused into the underlying PVD films 2511, 2521, 3211, and 4211. It can suppress by including. As a result, even if the layer using Cr is thickened, it is possible to suppress the diffusion of Cr into the electrode PVD films 2512, 2522, 3212, and 4212, and the layer using Cr can be made thick. Variation can be suppressed. Actually, even if the Cr layer is 0.2 μm, the diffusion of Cr into the electrode PVD films 2512, 2522, 3212, and 4212 can be suppressed. In this configuration, the wettability of the bonding material 11 made of a metal brazing material such as gold tin does not deteriorate due to the diffusion of Cr to the electrode surface. If Cr diffuses on the electrode surface constituting the sealing part (vibrator side sealing pattern and sealing part side sealing pattern, etc.), the wettability of the bonding material in the sealing part becomes worse, and the bonding material is applied. Since unevenness can occur, as a result, after the sealing portion is joined with a joining material and hermetically sealed, the hermetic sealing property may be adversely affected. In this configuration, such a problem does not occur.

  In the present embodiment, the second sealing member 4 is a rectangular parallelepiped substrate formed from a single glass wafer, but is not limited to this, and the two sealing members 4 are formed from two rectangular parallelepipeds formed from a glass wafer. There may be. In this case, the sealing-side second bonding pattern 421, the third through-hole 442, and the other external electrode terminal 432 are formed on one rectangular parallelepiped substrate, and the substrate is hermetically sealed, and the other rectangular parallelepiped substrate. In addition, the second through hole 441 and one external electrode terminal 431 are formed. According to this configuration, a pair of external electrode terminals (one external electrode terminal 431 and another external electrode terminal 432) can be completely separated, and a short circuit can be prevented. Further, when two rectangular parallelepiped second sealing members 4 are formed of a metal material instead of a glass wafer, there is no need to form third through holes 442, and the number of through holes is reduced, contributing to downsizing. it can.

  In the above embodiment, a surface-mount type crystal resonator is taken as an example of the piezoelectric vibration device, but the present invention can be applied to other piezoelectric vibration devices such as a crystal filter and a crystal oscillator, and is not limited to the surface-mount type.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit, gist, or main features. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention is suitable for a crystal vibration device using quartz as a material for a substrate of a piezoelectric vibration plate.

101 Quartz Crystal 11 Bonding Material 12 Package 13 Internal Space 2 Crystal Diaphragm 211 One Main Surface 212 Other Main Surface 213 Conducting Path 221 First Excitation Electrode 222 Second Excitation Electrode 223 First Extraction Electrode 224 Second Extraction Electrode 23 Vibration Unit 24 Notch 241 Plane-view concave body 242 Plane-view rectangular body 25 Vibration-side sealing portion 251 Vibration-side first bonding pattern 2511 Base PVD film 2512 Electrode PVD film 252 Vibration-side second joint pattern 2521 Base PVD film 2522 Electrode PVD film 261 First through hole 3 First sealing member 311 One main surface 312 Other main surface 32 Sealing side first sealing portion 321 Sealing side first bonding pattern 3211 Base PVD film 3212 Electrode PVD film 4 Second sealing Stop member 411 One main surface 412 Other main surface 42 Sealing side second sealing portion 421 Sealing side second bonding pattern 4211 Underlying PVD film 42 12 Electrode PVD film 431 One external electrode terminal 4311 Base PVD film 4312 Electrode PVD film 432 Other external electrode terminal 4321 Base PVD film 4322 Electrode PVD film 441 Second through hole 442 Third through hole

Claims (2)

A piezoelectric diaphragm in which a sealing portion is integrally formed around the vibrating portion and the vibrating portion;
A piezoelectric vibration device comprising a sealing portion on both main surfaces of the piezoelectric vibration plate and a pair of plate-shaped sealing members that are joined and hermetically sealed via a metal brazing material,
On each main surface of the piezoelectric diaphragm, an excitation electrode is formed on the vibration portion, a sealing pattern is formed on the sealing portion, and an extraction electrode that pulls the excitation electrode into the sealing pattern is formed.
In the portion of the sealing pattern close to the extraction electrode, a part of the sealing pattern forms a floating island pattern separated from the sealing pattern,
A dividing portion is formed between the floating island pattern and the extraction electrode inside the sealing portion,
The floating part pattern and the extraction electrode are connected to the upper part of the divided part by a metal film having low wettability with the metal brazing material,
Each sealing member is formed with a sealing-side sealing pattern for joining with the sealing pattern of the piezoelectric diaphragm,
The sealing side sealing pattern of each sealing member and the sealing pattern and floating island pattern of each main surface of the piezoelectric diaphragm are joined with a metal brazing material, and each excitation electrode is sealed with each sealing side A piezoelectric vibration device comprising a pattern or a part of a connection path led out to the outside through each sealing pattern. The piezoelectric vibration device according to claim 1, wherein the metal brazing material is an alloy containing tin.

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