WO2010023731A1 - 圧電振動子、発振器、電子機器及び電波時計、並びに圧電振動子の製造方法 - Google Patents
圧電振動子、発振器、電子機器及び電波時計、並びに圧電振動子の製造方法 Download PDFInfo
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- WO2010023731A1 WO2010023731A1 PCT/JP2008/065250 JP2008065250W WO2010023731A1 WO 2010023731 A1 WO2010023731 A1 WO 2010023731A1 JP 2008065250 W JP2008065250 W JP 2008065250W WO 2010023731 A1 WO2010023731 A1 WO 2010023731A1
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- base substrate
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Classifications
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- H—ELECTRICITY
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- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/05—Holders; Supports
- H03H9/10—Mounting in enclosures
- H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
- H03H9/1014—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the BAW device
- H03H9/1021—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the BAW device the BAW device being of the cantilever type
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/21—Crystal tuning forks
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/026—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the tuning fork type
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/42—Piezoelectric device making
Definitions
- the present invention relates to a surface mount type (SMD) piezoelectric vibrator in which a piezoelectric vibrating piece is accommodated in a cavity formed between two bonded substrates, an oscillator having the piezoelectric vibrator, an electronic device, and
- SMD surface mount type
- the present invention relates to a radio timepiece and a method for manufacturing a piezoelectric vibrator for manufacturing the piezoelectric vibrator.
- a piezoelectric vibrator using a crystal or the like is used as a time source, a control signal timing source, a reference signal source, or the like in a mobile phone or a portable information terminal device.
- Various piezoelectric vibrators of this type are provided.
- a surface-mount type piezoelectric vibrator is known.
- this type of piezoelectric vibrator a three-layer structure type in which a piezoelectric substrate on which a piezoelectric vibrating piece is formed is joined so as to be sandwiched from above and below by a base substrate and a lid substrate is known. In this case, the piezoelectric vibrating piece is accommodated in a cavity (sealed chamber) formed between the base substrate and the lid substrate.
- This type of piezoelectric vibrator has a two-layer structure in which a base substrate and a lid substrate are directly joined, and a piezoelectric vibrating piece is accommodated in a cavity formed between the two substrates.
- This two-layer structure type piezoelectric vibrator is excellent in that it can be made thinner than the three-layer structure, and is preferably used.
- a piezoelectric vibrator having a lower equivalent resistance value (effective resistance value, Re)
- a piezoelectric vibrator having a low equivalent resistance value can vibrate the piezoelectric vibrating piece with low power, and thus becomes a piezoelectric vibrator with good energy efficiency.
- a method for suppressing the equivalent resistance value a method of bringing the inside of a cavity close to a vacuum is known.
- a method of bringing the inside of the cavity close to a vacuum a method (gettering) is known in which a getter material, which is a metal film, is accommodated in the cavity, and this getter material is heated by irradiating a laser from the outside and activated. (For example, refer to Patent Document 1).
- the gas in the cavity mainly made of oxygen can be absorbed by the chemical reaction by the activated getter material, the inside of the cavity can be brought close to a vacuum.
- This getter material is made of aluminum, titanium, zirconium, or an alloy thereof. However, when heated, the getter material absorbs more gas in the cavity and can effectively improve the degree of vacuum (getter).
- aluminum is preferably used because of its high ring effect. JP 2003-142976 A
- the quality of the piezoelectric vibrator may be degraded and the characteristics may be changed. That is, aluminum has a characteristic that it is easily eroded chemically by a medium such as moisture. For this reason, when the piezoelectric vibrator is placed in a high humidity environment, the getter material may be corroded by moisture. When corrosion occurs, the surface of the getter material is significantly etched, or corrosion products appear on the surface. Therefore, not only the quality is deteriorated, but also the vibration operation of the piezoelectric vibrating piece is affected, and there is a possibility that the characteristic is changed.
- the present invention has been made in view of such circumstances, and its purpose is to provide a piezoelectric vibrator that can still exhibit a high gettering effect and is less susceptible to quality deterioration and characteristic changes due to the influence of humidity. Is to provide.
- Another object of the present invention is to provide a piezoelectric vibrator manufacturing method for manufacturing the piezoelectric vibrator, an oscillator having the piezoelectric vibrator, an electronic device, and a radio timepiece.
- a method of manufacturing a piezoelectric vibrator according to the present invention includes a base substrate and a lid substrate that are bonded to each other and that have a cavity formed therebetween, an external electrode that is formed on a lower surface of the base substrate, and an inside of the cavity.
- a piezoelectric vibrator comprising: a piezoelectric vibrating piece housed in the cavity in a state of being electrically connected to the getter material; and a getter material formed in the cavity, the getter material comprising: It is made of chromium or a metal material mainly composed of chromium.
- the getter material is formed of chromium or a metal material containing chromium as a main component, high corrosion resistance can be exhibited. That is, since chromium is more excellent in corrosion resistance than aluminum, the corrosion resistance of the getter material can be further improved as compared with the conventional case formed of aluminum. For this reason, even if this piezoelectric vibrator is used in a high humidity environment, the getter material is unlikely to corrode. Therefore, it is difficult to cause quality deterioration and characteristic change due to corrosion. Moreover, chromium has excellent corrosion resistance and is easy to bond with oxygen.
- the getter material when gettering is heated, the getter material is heated to evaporate and easily absorbs the gas in the cavity made of oxygen. High effect. That is, a gettering effect equivalent to or higher than that of a conventional getter material formed of aluminum can be expected. For this reason, since the degree of vacuum in the cavity can be improved in a short time, the piezoelectric vibrator can be manufactured efficiently.
- the getter material may be formed on the upper surface of the base substrate.
- the getter material is not formed on the piezoelectric vibrating piece, but on either the base substrate or the lid substrate. Therefore, even when the getter material is heated with a laser or the like during gettering, the piezoelectric vibrating piece is not affected by heating. Therefore, a load due to heating is not applied to the piezoelectric vibrating piece. For this reason, since the quality and characteristics of the piezoelectric vibrator are not affected at all, the quality of the piezoelectric vibrator can be improved.
- the internal electrode may be formed of the same material as the getter material and simultaneously with the getter material.
- the piezoelectric vibrator can be manufactured more efficiently.
- the piezoelectric vibrator according to the present invention is accommodated in the cavity, the base substrate and the lid substrate, which are bonded to each other and formed with a cavity therebetween, the external electrode formed on the lower surface of the base substrate, and the cavity.
- the internal electrode formed on the upper surface of the base substrate and the base substrate are formed so as to penetrate, and the external electrode and the internal electrode are electrically connected to the through electrode and the internal electrode.
- the getter material may be formed on an upper surface of the base substrate.
- the internal electrode may be formed of the same material as the getter material and at the same time as the getter material.
- the piezoelectric vibrator described in any one of (4) to (6) is electrically connected to an integrated circuit as an oscillator.
- the piezoelectric vibrator described in any one of the above (4) to (6) is electrically connected to the timing unit.
- the piezoelectric vibrator described in any one of (4) to (6) is electrically connected to the filter unit.
- oscillators electronic devices and radio timepieces, they are equipped with high-quality and highly reliable piezoelectric vibrators that do not easily cause quality degradation or characteristic changes even when used in high humidity conditions.
- the quality of the product can be improved by increasing the reliability.
- the piezoelectric vibrator of the present invention According to the piezoelectric vibrator of the present invention, a high gettering effect can still be exhibited, and quality deterioration and characteristic change can hardly be caused by the influence of humidity. Therefore, the operation reliability can be improved.
- the method for manufacturing a piezoelectric vibrator according to the present invention the above-described piezoelectric vibrator can be reliably manufactured.
- the oscillator, the electronic device, and the radio timepiece according to the present invention since the above-described piezoelectric vibrator is provided, it is possible to improve the reliability of the operation and improve the quality.
- FIG. 1 is an external perspective view showing an embodiment of a piezoelectric vibrator of the present invention.
- FIG. 2 is an internal configuration diagram of the piezoelectric vibrator shown in FIG. 1 and is a view of the piezoelectric vibrating piece viewed from above with the lid substrate removed.
- FIG. 3 is a cross-sectional view of the piezoelectric vibrator taken along line AA shown in FIG.
- FIG. 4 is a cross-sectional view of the piezoelectric vibrator taken along line BB shown in FIG.
- FIG. 5 is an exploded perspective view of the piezoelectric vibrator shown in FIG. 6 is a top view of a piezoelectric vibrating piece constituting the piezoelectric vibrator shown in FIG.
- FIG. 7 is a bottom view of the piezoelectric vibrating piece shown in FIG.
- FIG. 8 is a sectional view taken along the line CC in FIG.
- FIG. 9 is a flowchart showing a flow of manufacturing the piezoelectric vibrator shown in FIG.
- FIG. 10 is a diagram showing a step in manufacturing the piezoelectric vibrator according to the flowchart shown in FIG. 9, and shows a state in which a plurality of recesses are formed on the lid substrate wafer that is the base of the lid substrate. It is.
- FIG. 11 is a diagram showing a step in manufacturing the piezoelectric vibrator according to the flowchart shown in FIG.
- FIG. 12 is an overall view of the base substrate wafer in the state shown in FIG.
- FIG. 13 is a diagram showing one process when the piezoelectric vibrator is manufactured according to the flowchart shown in FIG. 9, and the base substrate wafer, the lid substrate wafer, It is a disassembled perspective view of the wafer body by which anodic bonding was carried out.
- FIG. 14 is a configuration diagram showing an embodiment of an oscillator according to the present invention.
- FIG. 15 is a configuration diagram showing an embodiment of an electronic apparatus according to the invention.
- FIG. 16 is a block diagram showing an embodiment of a radio timepiece according to the present invention.
- FIG. 17 is a table showing the results of the examples using the piezoelectric vibrator according to the present invention.
- the piezoelectric vibrator 1 of the present embodiment is formed in a box shape in which a base substrate 2 and a lid substrate 3 are laminated in two layers, and a piezoelectric element is formed in an internal cavity C.
- This is a surface-mount type piezoelectric vibrator in which the resonator element 4 is accommodated.
- the excitation electrode 15, the extraction electrodes 19 and 20, the mount electrodes 16 and 17, and the weight metal film 21, which will be described later, are omitted for easy understanding of the drawing.
- the piezoelectric vibrating piece 4 is a tuning fork type vibrating piece formed of a piezoelectric material such as crystal, lithium tantalate, or lithium niobate, as shown in FIGS. 6 to 8, and when a predetermined voltage is applied. It vibrates.
- the piezoelectric vibrating reed 4 includes a pair of vibrating arm portions 10 and 11 arranged in parallel, a base portion 12 that integrally fixes the base end sides of the pair of vibrating arm portions 10 and 11, and a pair of vibrating arm portions.
- the piezoelectric vibrating reed 4 includes groove portions 18 formed along the longitudinal direction of the vibrating arm portions 10 and 11 on both main surfaces of the pair of vibrating arm portions 10 and 11. .
- the groove portion 18 is formed from the proximal end side of the vibrating arm portions 10 and 11 to the vicinity of the middle.
- the excitation electrode 15 including the first excitation electrode 13 and the second excitation electrode 14 is an electrode that vibrates the pair of vibrating arm portions 10 and 11 at a predetermined resonance frequency in a direction approaching or separating from each other. Patterned on the outer surfaces of the vibrating arm portions 10 and 11 while being electrically separated from each other. Specifically, as shown in FIG. 8, the first excitation electrode 13 is mainly formed on the groove portion 18 of one vibration arm portion 10 and on both side surfaces of the other vibration arm portion 11. The excitation electrode 14 is mainly formed on both side surfaces of one vibration arm portion 10 and on the groove portion 18 of the other vibration arm portion 11.
- the first excitation electrode 13 and the second excitation electrode 14 are mounted on the main surfaces of the base portion 12 via the extraction electrodes 19 and 20, respectively, on the main electrodes 12. Is electrically connected. A voltage is applied to the piezoelectric vibrating reed 4 via the mount electrodes 16 and 17.
- the excitation electrode 15, the mount electrodes 16 and 17, and the extraction electrodes 19 and 20 described above are made of a conductive film such as chromium (Cr), nickel (Ni), aluminum (Al), or titanium (Ti). It is formed.
- a weight metal film 21 for adjusting (frequency adjustment) so as to vibrate its own vibration state within a predetermined frequency range is coated on the tips of the pair of vibrating arm portions 10 and 11.
- the weight metal film 21 is divided into a coarse adjustment film 21a used when the frequency is roughly adjusted and a fine adjustment film 21b used when the frequency is finely adjusted.
- the piezoelectric vibrating reed 4 configured as described above is bump-bonded to the upper surface of the base substrate 2 using bumps B such as gold as shown in FIGS. More specifically, bump bonding is performed with a pair of mount electrodes 16 and 17 in contact with bumps B formed on lead electrodes (internal electrodes) 36 and 37, which will be described later, patterned on the upper surface of the base substrate 2, respectively. Has been. As a result, the piezoelectric vibrating reed 4 is supported in a state of floating from the upper surface of the base substrate 2 and the mount electrodes 16 and 17 and the routing electrodes 36 and 37 are electrically connected to each other.
- the lid substrate 3 is a transparent insulating substrate made of a glass material, for example, soda-lime glass, and is formed in a plate shape as shown in FIGS.
- a rectangular recess 3 a in which the piezoelectric vibrating reed 4 is accommodated is formed on the bonding surface side to which the base substrate 2 is bonded.
- the recess 3 a is a cavity recess that serves as a cavity C that accommodates the piezoelectric vibrating reed 4 when the substrates 2 and 3 are overlapped.
- the lid substrate 3 is anodically bonded to the base substrate 2 with the recess 3a facing the base substrate 2 side.
- the base substrate 2 is a transparent insulating substrate made of a glass material, for example, soda lime glass, like the lid substrate 3, and can be superimposed on the lid substrate 3 as shown in FIGS. 1 to 3 and FIG. It is formed in a plate shape with a large size.
- the base substrate 2 is formed with a pair of through electrodes 32 and 33 formed so as to penetrate the base substrate 2 in the vertical direction so that one end of each of the through electrodes 32 and 33 is accommodated in the cavity C.
- the through-electrodes 32 and 33 are formed between the base substrate 2 without a gap and maintain airtightness in the cavity C, and electrically connect external electrodes 38 and 39 to be described later with the routing electrodes 36 and 37. .
- the upper surface side of the base substrate 2 (the bonding surface side to which the lid substrate 3 is bonded) is formed in the cavity C and heated to reduce the degree of vacuum in the cavity C.
- a getter material 34 made of a metal material to be improved, a bonding film 35 for anodic bonding, and a pair of routing electrodes 36 and 37 are patterned.
- the bonding film 35 is made of a conductive material such as aluminum, and is formed along the periphery of the base substrate 2 so as to surround the periphery of the recess 3 a formed in the lid substrate 3.
- the getter material 34 is made of chromium or a metal material mainly composed of chromium.
- the getter material 34 includes a base layer 34 a made of chromium formed on the base substrate 2 and a finishing layer 34 b made of gold stacked on the base layer 34 a. ing. Further, as shown in FIG. 2, two are formed so as to be opposed to each other on both sides of the piezoelectric vibrating reed 4 in a plan view. Each getter material 34 is formed so as to be adjacent to and extend in parallel with the vibrating arm portions 10 and 11 in a plan view.
- each lead-out electrode 36, 37 includes a base layer 37a made of chromium formed on the base substrate 2 and a finish layer made of gold stacked on the base layer 37a. 37b.
- the pair of routing electrodes 36 and 37 includes one routing electrode 36 that electrically connects one penetration electrode 32 and one mount electrode 16 of the piezoelectric vibrating reed 4, and the other routing electrode 37 includes The other through electrode 33 and the other mount electrode 17 of the piezoelectric vibrating piece 4 are patterned so as to be electrically connected.
- external electrodes 38 and 39 that are electrically connected to the pair of through electrodes 32 and 33 are formed on the lower surface of the base substrate 2. . That is, one external electrode 38 is electrically connected to the first excitation electrode 13 of the piezoelectric vibrating reed 4 via one through electrode 32 and one routing electrode 36. The other external electrode 39 is electrically connected to the second excitation electrode 14 of the piezoelectric vibrating reed 4 via the other through electrode 33 and the other routing electrode 37. As a result, the pair of excitation electrodes 15 can be electrically connected to the outside of the cavity C, respectively.
- a predetermined drive voltage is applied to the external electrodes 38 and 39 formed on the base substrate 2.
- a current can flow through the excitation electrode 15 including the first excitation electrode 13 and the second excitation electrode 14 of the piezoelectric vibrating reed 4, and is predetermined in a direction in which the pair of vibrating arm portions 10 and 11 are approached and separated.
- Can be vibrated at a frequency of The vibration of the pair of vibrating arm portions 10 and 11 can be used as a time source, a control signal timing source, a reference signal source, and the like.
- a plurality of the piezoelectric vibrators 1 described above are manufactured at once using a base substrate wafer (base substrate) 40 and a lid substrate wafer (lid substrate) 50 with reference to the flowchart shown in FIG.
- the manufacturing method will be described below.
- a plurality of piezoelectric vibrators 1 are manufactured at a time using a wafer-like substrate.
- the present invention is not limited to this, and dimensions are adjusted in advance to the outer shapes of the base substrate 2 and the lid substrate 3. It is also possible to process only one product and manufacture only one at a time.
- the piezoelectric vibrating piece 4 shown in FIGS. 6 to 8 is manufactured (S10). Specifically, a quartz Lambert rough is first sliced at a predetermined angle to obtain a wafer having a constant thickness. Next, this wafer is lapped and roughly processed, and then the work-affected layer is removed by etching, and then mirror polishing such as polishing is performed to obtain a wafer having a predetermined thickness.
- the wafer is patterned with the outer shape of the piezoelectric vibrating reed 4 by a photolithography technique, and a metal film is formed and patterned to obtain the excitation electrode 15, Lead electrodes 19 and 20, mount electrodes 16 and 17, and weight metal film 21 are formed. Thereby, the some piezoelectric vibrating piece 4 is producible.
- the resonance frequency is coarsely adjusted. This is done by irradiating the coarse adjustment film 21a of the weight metal film 21 with laser light to evaporate a part thereof and changing the weight. Note that fine adjustment for adjusting the resonance frequency with higher accuracy is performed after mounting. This will be described later.
- a lid substrate wafer 50 to be the lid substrate 3 later is manufactured up to the state immediately before anodic bonding (S20).
- a disk-shaped lid substrate wafer 50 is formed by removing the outermost work-affected layer by etching or the like (S21).
- a recess forming step as shown in FIG. 10, a plurality of cavity recesses 3a are formed in the matrix direction by etching or the like on the bonding surface of the lid substrate wafer 50 (S22). At this point, the first wafer manufacturing process is completed.
- a base substrate wafer 40 that will later become the base substrate 2 is fabricated to a state just before anodic bonding (S30). ).
- the soda lime glass is polished to a predetermined thickness and washed, and then the outermost work-affected layer is removed by etching or the like, from the disc-shaped soda lime glass.
- a wafer 40 is formed (S31).
- a through electrode forming step a plurality of pairs of through electrodes 32 and 33 are formed on the base substrate wafer 40 (S32).
- a pair of through electrodes 32 and 33 are formed in the plurality of through holes.
- the pair of through electrodes 32 and 33 ensure the conductivity between the upper surface side and the lower surface side of the base substrate wafer 40.
- the getter material 34 is formed as a getter material forming step (S33), and the lead electrodes 36 and 37 are formed as a lead electrode forming step (S34).
- the base layers 34a and 37a made of chromium are first patterned, and then patterned such that the finishing layers 34b and 37b made of gold are stacked on the base layers 34a and 37a.
- the base layer 34a is patterned, when the piezoelectric vibrating reed 4 is mounted on the base substrate wafer 40 later, two layers are formed so as to face each other with the piezoelectric vibrating reed 4 interposed therebetween in plan view.
- Each getter material 34 is formed so as to be adjacent to and extend parallel to the vibrating arm portions 10 and 11 in a plan view.
- the lead-out electrodes 36 and 37 are formed simultaneously with the getter material 34, the piezoelectric vibrator 1 can be manufactured more efficiently.
- gold is used as the finishing layer 37b of the routing electrodes 36 and 37, the conductivity of the routing electrodes 36 and 37 can be secured stably, and the quality of the piezoelectric vibrator 1 can be improved.
- a conductive material is patterned on the upper surface of the base substrate wafer 40 to form a bonding film 35 as shown in FIGS. 11 and 12 (S35).
- the dotted line M shown in FIG.11 and FIG.12 has shown the cutting line cut
- the bonding film 35 is not shown for easy viewing. At this point, the second wafer manufacturing process is completed.
- the produced plurality of piezoelectric vibrating reeds 4 are joined to the upper surface of the base substrate wafer 40 via the routing electrodes 36 and 37, respectively (S40).
- bumps B such as gold are formed on the pair of lead-out electrodes 36 and 37, respectively.
- the piezoelectric vibrating piece 4 is pressed against the bump B while heating the bump B to a predetermined temperature (for example, 300 ° C.).
- a predetermined temperature for example, 300 ° C.
- the lid substrate wafer 50 is superimposed on the base substrate wafer 40 as an overlaying step (S50). Specifically, both wafers 40 and 50 are aligned at the correct positions while using a reference mark (not shown) as an index. As a result, the piezoelectric vibrating reed 4, the getter material 34, and the routing electrodes 36 and 37 are accommodated in the cavity C surrounded by the recess 3 a formed in the base substrate wafer 40 and the two wafers 40 and 50. .
- the two superposed wafers 40 and 50 are put into an anodic joining apparatus (not shown), and a predetermined voltage is applied in a predetermined temperature atmosphere to perform anodic bonding (S60). Specifically, a predetermined voltage is applied between the bonding film 35 and the lid substrate wafer 50. As a result, an electrochemical reaction occurs at the interface between the bonding film 35 and the lid substrate wafer 50, and the two are firmly bonded and anodically bonded. Thereby, the piezoelectric vibrating reed 4 can be sealed in the cavity C, and the wafer body 60 shown in FIG. 13 in which the base substrate wafer 40 and the lid substrate wafer 50 are bonded can be obtained. In FIG. 13, in order to make the drawing easy to see, a state in which the wafer body 60 is disassembled is illustrated, and the bonding film 35 is not illustrated from the base substrate wafer 40. In addition, the dotted line M shown in FIG.
- a conductive material is patterned on the lower surface of the base substrate wafer 40 to form a plurality of pairs of external electrodes 38 and 39 electrically connected to the pair of through electrodes 32 and 33, respectively. (S70).
- the piezoelectric vibrating reed 4 accommodated in the cavity C can be operated using the external electrodes 38 and 39.
- the getter material 34 accommodated in each cavity C of the wafer body 60 is heated to adjust the degree of vacuum in the cavity C (S80).
- the wafer body 60 is set in a gettering adjuster (not shown), and a predetermined voltage is applied to the external electrodes 38 and 39 in the gettering adjuster to vibrate the piezoelectric vibrating reed 4 to obtain an equivalent resistance value.
- Measure the series vibration resistance value proportional to Based on the series vibration resistance value for example, the getter material 34 is heated by irradiating laser from the base substrate wafer 40 side, and gettering is performed an appropriate number of times.
- a threshold value of the series vibration resistance value may be set in advance for each type of piezoelectric vibrator, and may be determined to be appropriate when the threshold value is exceeded. Also, gettering is performed after storing the series vibration resistance value immediately before gettering, calculating the rate of change from the series vibration resistance value immediately after gettering, and comparing the rate of change with a preset value. You may judge by.
- the frequency of each piezoelectric vibrating reed 4 accommodated in the cavity C is finely adjusted to fall within a predetermined range (S90). More specifically, a voltage is applied to the pair of external electrodes 38 and 39 formed on the lower surface of the base substrate wafer 40 to vibrate the piezoelectric vibrating reed 4. Then, laser light is irradiated from the outside through the base substrate wafer 40 while measuring the frequency to evaporate the fine-tuning film 21 b of the weight metal film 21. Thereby, since the weight of the tip end side of the pair of vibrating arm portions 10 and 11 is changed, the frequency of the piezoelectric vibrating piece 4 can be finely adjusted so as to be within a predetermined range of the nominal frequency.
- the bonded wafer body 60 is cut along the cutting line M shown in FIG. 13 into small pieces (S100).
- the piezoelectric vibrating reed 4 is housed in the cavity C formed between the base substrate 2 and the lid substrate 3 bonded to each other, and the two-layer structure surface-mount type piezoelectric vibrator 1 shown in FIG. A plurality of can be manufactured at a time.
- the order of processes in which the fine adjustment process (S90) is performed may be used.
- fine adjustment step (S90) fine adjustment can be performed in the state of the wafer body 60, so that the plurality of piezoelectric vibrators 1 can be finely adjusted more efficiently. Therefore, it is preferable because throughput can be improved.
- an internal electrical characteristic inspection is performed (S110). That is, the resonance frequency, resonance resistance value, drive level characteristic (excitation power dependency of the resonance frequency and resonance resistance value) and the like of the piezoelectric vibrating piece 4 are measured and checked. In addition, the insulation resistance characteristics and the like are also checked. Finally, an appearance inspection of the piezoelectric vibrator 1 is performed to finally check dimensions, quality, and the like. This completes the manufacture of the piezoelectric vibrator 1.
- the getter material 34 includes the base layer 34a made of chromium, high corrosion resistance can be exhibited. That is, since chromium is superior in corrosion resistance as compared with aluminum, the corrosion resistance of the getter material 34 can be further improved as compared with the conventional case formed of aluminum. For this reason, even if the piezoelectric vibrator 1 is used in a high humidity environment, the getter material 34 is hardly corroded. Therefore, it is difficult to cause quality deterioration and characteristic change due to corrosion. Therefore, the operation reliability can be improved. Moreover, chromium is excellent in corrosion resistance and easily binds to oxygen.
- the gettering process when the getter material 34 is heated and evaporated, the gas in the cavity C mainly composed of oxygen is easily absorbed. High gettering effect. That is, a gettering effect equivalent to or higher than that of a conventional getter material formed of aluminum can be expected. For this reason, since the degree of vacuum in the cavity C can still be improved in a short time, the piezoelectric vibrator 1 can be manufactured efficiently.
- the getter material 34 is formed not on the piezoelectric vibrating piece 4 but on the base substrate wafer 40 (base substrate 2). Therefore, even when the getter material 34 is heated with a laser or the like in the gettering step, the piezoelectric vibrating piece 4 is not affected by heating. Therefore, no load due to heating is applied to the piezoelectric vibrating reed 4. For this reason, since the quality and characteristics of the piezoelectric vibrator 1 are not affected at all, the quality of the piezoelectric vibrator 1 can be improved.
- the oscillator 100 is configured such that the piezoelectric vibrator 1 is an oscillator electrically connected to the integrated circuit 101.
- the oscillator 100 includes a substrate 103 on which an electronic component 102 such as a capacitor is mounted. On the substrate 103, the integrated circuit 101 for the oscillator is mounted, and the piezoelectric vibrator 1 is mounted in the vicinity of the integrated circuit 101.
- the electronic component 102, the integrated circuit 101, and the piezoelectric vibrator 1 are electrically connected by a wiring pattern (not shown). Each component is molded with a resin (not shown).
- the piezoelectric vibrating reed 4 in the piezoelectric vibrator 1 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece 4 and input to the integrated circuit 101 as an electric signal.
- the input electrical signal is subjected to various processes by the integrated circuit 101 and is output as a frequency signal.
- the piezoelectric vibrator 1 functions as an oscillator.
- an RTC real-time clock
- a function for controlling the time, providing a time, a calendar, and the like can be added.
- the oscillator 100 of this embodiment since the operation reliability is improved and the high-quality piezoelectric vibrator 1 is provided, the oscillator 100 itself also increases the operation reliability. High quality. In addition to this, it is possible to obtain a highly accurate frequency signal that is stable over a long period of time.
- the portable information device 110 having the above-described piezoelectric vibrator 1 will be described as an example of the electronic device.
- the portable information device 110 according to the present embodiment is represented by, for example, a mobile phone, and is a development and improvement of a wrist watch in the related art. The appearance is similar to that of a wristwatch, and a liquid crystal display is arranged in a portion corresponding to a dial so that the current time and the like can be displayed on this screen.
- a communication device it is possible to perform communication similar to that of a conventional mobile phone by using a speaker and a microphone that are removed from the wrist and incorporated in the inner portion of the band. However, it is much smaller and lighter than conventional mobile phones.
- the portable information device 110 includes the piezoelectric vibrator 1 and a power supply unit 111 for supplying power.
- the power supply unit 111 is made of, for example, a lithium secondary battery.
- the power supply unit 111 includes a control unit 112 that performs various controls, a clock unit 113 that counts time, a communication unit 114 that communicates with the outside, a display unit 115 that displays various types of information, A voltage detection unit 116 that detects the voltage of the functional unit is connected in parallel.
- the power unit 111 supplies power to each functional unit.
- the control unit 112 controls each function unit to control operation of the entire system such as transmission and reception of voice data, measurement and display of the current time, and the like.
- the control unit 112 includes a ROM in which a program is written in advance, a CPU that reads and executes the program written in the ROM, and a RAM that is used as a work area of the CPU.
- the clock unit 113 includes an integrated circuit including an oscillation circuit, a register circuit, a counter circuit, an interface circuit, and the like, and the piezoelectric vibrator 1.
- the piezoelectric vibrating piece 4 vibrates, and this vibration is converted into an electric signal by the piezoelectric characteristics of the crystal and is input to the oscillation circuit as an electric signal.
- the output of the oscillation circuit is binarized and counted by a register circuit and a counter circuit. Then, signals are transmitted to and received from the control unit 112 via the interface circuit, and the current time, current date, calendar information, or the like is displayed on the display unit 115.
- the communication unit 114 has functions similar to those of a conventional mobile phone, and includes a radio unit 117, a voice processing unit 118, a switching unit 119, an amplification unit 120, a voice input / output unit 121, a telephone number input unit 122, and a ring tone generation unit. 123 and a call control memory unit 124.
- the wireless unit 117 exchanges various data such as audio data with the base station via the antenna 125.
- the audio processing unit 118 encodes and decodes the audio signal input from the radio unit 117 or the amplification unit 120.
- the amplifying unit 120 amplifies the signal input from the audio processing unit 118 or the audio input / output unit 121 to a predetermined level.
- the voice input / output unit 121 includes a speaker, a microphone, and the like, and amplifies a ringtone and a received voice or collects a voice.
- the ring tone generator 123 generates a ring tone in response to a call from the base station.
- the switching unit 119 switches the amplifying unit 120 connected to the voice processing unit 118 to the ringing tone generating unit 123 only when an incoming call is received, so that the ringing tone generated in the ringing tone generating unit 123 is transmitted via the amplifying unit 120.
- the call control memory unit 124 stores a program related to incoming / outgoing call control of communication.
- the telephone number input unit 122 includes, for example, a number key from 0 to 9 and other keys. By pressing these number keys and the like, a telephone number of a call destination is input.
- the voltage detection unit 116 detects the voltage drop and notifies the control unit 112 of the voltage drop.
- the predetermined voltage value at this time is a value set in advance as a minimum voltage necessary for stably operating the communication unit 114, and is, for example, about 3V.
- the control unit 112 prohibits the operations of the radio unit 117, the voice processing unit 118, the switching unit 119, and the ring tone generation unit 123. In particular, it is essential to stop the operation of the wireless unit 117 with high power consumption. Further, the display unit 115 displays that the communication unit 114 has become unusable due to insufficient battery power.
- the operation of the communication unit 114 can be prohibited by the voltage detection unit 116 and the control unit 112, and that effect can be displayed on the display unit 115.
- This display may be a text message, but as a more intuitive display, a x (X) mark may be attached to the telephone icon displayed at the top of the display surface of the display unit 115.
- the function of the communication part 114 can be stopped more reliably by providing the power supply cutoff part 126 that can selectively cut off the power of the part related to the function of the communication part 114.
- the portable information device 110 of the present embodiment since the operation reliability is improved and the high-quality piezoelectric vibrator 1 is provided, the portable information device itself is similarly reliable in operation. It is possible to improve the quality and improve the quality. In addition to this, it is possible to display highly accurate clock information that is stable over a long period of time.
- the radio timepiece 130 of the present embodiment includes the piezoelectric vibrator 1 electrically connected to the filter unit 131, and receives a standard radio wave including timepiece information to accurately It is a clock with a function of automatically correcting and displaying the correct time.
- a standard radio wave including timepiece information to accurately It is a clock with a function of automatically correcting and displaying the correct time.
- transmitting stations transmit standard radio waves in Fukushima Prefecture (40 kHz) and Saga Prefecture (60 kHz), each transmitting standard radio waves.
- Long waves such as 40 kHz or 60 kHz have the property of propagating the surface of the earth and the property of propagating while reflecting the ionosphere and the surface of the earth, so the propagation range is wide, and the above two transmitting stations cover all of Japan. is doing.
- the antenna 132 receives a long standard wave of 40 kHz or 60 kHz.
- the long-wave standard radio wave is obtained by subjecting time information called a time code to AM modulation on a 40 kHz or 60 kHz carrier wave.
- the received long standard wave is amplified by the amplifier 133 and filtered and tuned by the filter unit 131 having the plurality of piezoelectric vibrators 1.
- the piezoelectric vibrator 1 according to this embodiment includes crystal vibrator portions 138 and 139 having resonance frequencies of 40 kHz and 60 kHz that are the same as the carrier frequency.
- the filtered signal having a predetermined frequency is detected and demodulated by the detection and rectification circuit 134.
- the time code is taken out via the waveform shaping circuit 135 and counted by the CPU 136.
- the CPU 136 reads information such as the current year, accumulated date, day of the week, and time. The read information is reflected in the RTC 137, and accurate time information is displayed. Since the carrier wave is 40 kHz or 60 kHz, the crystal vibrator units 138 and 139 are preferably vibrators having the tuning fork type structure described above.
- the frequency of the long standard radio wave is different overseas.
- a standard radio wave of 77.5 KHz is used. Therefore, when the radio timepiece 130 that can be used overseas is incorporated in a portable device, the piezoelectric vibrator 1 having a frequency different from that in Japan is required.
- the radio timepiece 130 of the present embodiment since the operation reliability is improved and the high-quality piezoelectric vibrator 1 is provided, the radio timepiece itself has the same operation reliability. The quality can be improved. In addition to this, it is possible to count time stably and with high accuracy over a long period of time.
- the getter material 34 is formed on the base substrate 2 (base substrate wafer 40). However, if the getter material 34 is formed in the cavity C, for example, the lid substrate 3 (lid substrate 3). For example, it may be formed on the surface of the piezoelectric vibrating reed 4. In the above embodiment, two getter members 34 are formed so as to be opposed to each other on both sides of the piezoelectric vibrating reed 4 in plan view. However, for example, the outside of the piezoelectric vibrating reed 4 in plan view. It may be formed adjacent to only one side.
- the getter material 34 includes the base layer 34a and the finishing layer 34b.
- the getter material 34 may be formed only of the chromium base layer 34a.
- an alloy containing chromium as a main component may be used as the getter material 34.
- the getter material forming step and the lead-out electrode forming step are performed at the same time, but may be performed at different timings.
- the grooved piezoelectric vibrating piece 4 in which the groove portions 18 are formed on both surfaces of the vibrating arm portions 10 and 11 has been described as an example.
- the piezoelectric vibrating piece may be used.
- the tuning fork type piezoelectric vibrating piece 4 has been described as an example.
- the tuning fork type is not limited to the tuning fork type.
- it may be a thickness sliding vibration piece.
- the base substrate 2 and the lid substrate 3 are anodically bonded via the bonding film 35.
- the present invention is not limited to anodic bonding.
- anodic bonding is preferable because both substrates 2 and 3 can be firmly bonded.
- the piezoelectric vibrating reed 4 is bump-bonded, but is not limited to bump bonding.
- the piezoelectric vibrating reed 4 may be joined with a conductive adhesive.
- the piezoelectric vibrating reed 4 can be lifted from the upper surface of the base substrate 2, and a minimum vibration gap necessary for vibration can be secured naturally. Therefore, it is preferable to perform bump bonding.
- a predetermined voltage is applied to the piezoelectric vibrator according to the present invention and the conventional piezoelectric vibrator to vibrate, and a series resonance resistance value R1 (hereinafter simply referred to as R1 value) proportional to the equivalent resistance value Re. ) Is shown below. Since the equivalent resistance value Re is inversely proportional to the degree of vacuum in the cavity as described above, the R1 value is also inversely proportional to the degree of vacuum in the cavity. The lower the R1 value, the higher the degree of vacuum in the cavity. become.
- a piezoelectric vibrator according to the present invention was used in which the getter material was formed only of chromium and the getter material had a thickness of 600 mm.
- a getter material made of only aluminum and having a thickness of 1100 mm was used as a conventional piezoelectric vibrator. That is, the getter material of the piezoelectric vibrator according to the present invention is thinner than the getter material of the conventional piezoelectric vibrator. Then, for the piezoelectric vibrator according to the present invention and the conventional piezoelectric vibrator, conditions are obtained except for the configuration of the getter material, each piezoelectric vibrator is gettered the same number of times, and R1 values before and after gettering are obtained. Compared.
- the comparison results are shown in the table of FIG.
- the table of FIG. 17 shows the R1 value before and after gettering (before gettering (K ⁇ ): A, for each of the conventional piezoelectric vibrator (Al (1100 ⁇ ) and the piezoelectric vibrator (Cr (600 ⁇ )) according to the present invention.
- 6 is a table showing the amount of decrease in R1 value (reduction amount (K ⁇ ): AB) after gettering (K ⁇ ): B) and before and after gettering.
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Abstract
Description
等価抵抗値を抑えるための一般的な方法の一つとしては、キャビティ内を真空に近づける方法が知られている。そして、キャビティ内を真空に近づける方法として、キャビティ内に金属膜であるゲッター材を収容し、外部よりレーザ等を照射してこのゲッター材を加熱し、活性化させる方法(ゲッタリング)が知られている(例えば、特許文献1参照)。
(1)本発明に係る圧電振動子の製造方法は、互いに接合され、間にキャビティが形成されたベース基板及びリッド基板と、前記ベース基板の下面に形成された外部電極と、前記キャビティ内に収容されるように前記ベース基板の上面に形成された内部電極と、前記ベース基板を貫通するように形成され、前記外部電極と前記内部電極とを電気的に接続する貫通電極と、前記内部電極に電気的に接続された状態で前記キャビティ内に収容された圧電振動片と、前記キャビティ内に形成されたゲッター材と、を備える圧電振動子を製造する方法であって、前記ゲッター材を、クロム若しくはクロムを主成分とする金属材料で形成する。
しかも、クロムは耐食性が優れている上に、酸素と結合し易いので、ゲッタリングの際、ゲッター材が加熱されて蒸発したときに主に酸素からなるキャビティ内のガスを吸収し易く、ゲッタリング効果が高い。つまり、アルミニウムで形成していた従来のゲッター材と同等或いはそれ以上のゲッタリング効果を期待することができる。このため、キャビティ内の真空度を依然として短時間で向上させることができるので、圧電振動子を効率良く製造することができる。
(8)また、本発明に係る電子機器は、上記(4)~(6)の何れか1項に記載の圧電振動子が、計時部に電気的に接続されている。
(9)また、本発明に係る電波時計は、上記(4)~(6)の何れか1項に記載の圧電振動子が、フィルタ部に電気的に接続されている。
また、本発明に係る圧電振動子の製造方法によれば、前述した圧電振動子を確実に製造することができる。
また、本発明に係る発振器、電子機器及び電波時計によれば、上述した圧電振動子を備えているので、同様に動作の信頼性を高めて高品質化を図ることができる。
1 圧電振動子
2 ベース基板
3 リッド基板
4 圧電振動片
34 ゲッター材
32、33 貫通電極
36、37 引き回し電極(内部電極)
38、39 外部電極
40 ベース基板用ウエハ(ベース基板)
50 リッド基板用ウエハ(リッド基板)
100 発振器
101 発振器の集積回路
110 携帯情報機器(電子機器)
113 電子機器の計時部
130 電波時計
131 電波時計のフィルタ部
本実施形態の圧電振動子1は、図1から図5に示すように、ベース基板2とリッド基板3とで2層に積層された箱状に形成されており、内部のキャビティC内に圧電振動片4が収容された表面実装型の圧電振動子である。
なお、図5においては、図面を見易くするために後述する励振電極15、引き出し電極19、20、マウント電極16、17及び重り金属膜21の図示を省略している。
この圧電振動片4は、平行に配置された一対の振動腕部10、11と、この一対の振動腕部10、11の基端側を一体的に固定する基部12と、一対の振動腕部10、11の外表面上に形成されて一対の振動腕部10、11を振動させる第1の励振電極13と第2の励振電極14とからなる励振電極15と、第1の励振電極13及び第2の励振電極14に電気的に接続されたマウント電極16、17とを有している。
また、本実施形態の圧電振動片4は、一対の振動腕部10、11の両主面上に、この振動腕部10、11の長手方向に沿ってそれぞれ形成された溝部18を備えている。この溝部18は、振動腕部10、11の基端側から略中間付近まで形成されている。
なお、上述した励振電極15、マウント電極16、17及び引き出し電極19、20は、例えば、クロム(Cr)、ニッケル(Ni)、アルミニウム(Al)やチタン(Ti)等の導電性膜の被膜により形成されたものである。
ベース基板2には、このベース基板2を上下方向に貫通するように形成された一対の貫通電極32、33が、それぞれの一端がキャビティC内に収まるように形成されている。
この貫通電極32、33は、ベース基板2との間に隙間なく形成されて、キャビティC内の気密を維持していると共に、後述する外部電極38、39と引き回し電極36、37とを導通させる。
特に、引き回し電極36、37をゲッター材34と同時に形成するので、圧電振動子1をより効率良く製造することができる。しかも、引き回し電極36、37の仕上層37bとして金を用いているので、引き回し電極36、37の導電性を安定に確保することができ、圧電振動子1の高品質化を図ることができる。
この時点で第2のウエハ作製工程が終了する。
なお、ゲッタリングの適正回数の判断方法としては、例えば、圧電振動子の種類ごとに直列振動抵抗値の閾値を予め設定しておき、この閾値を下回った際に適正と判断する方法としてもよい。また、ゲッタリング直前の直列振動抵抗値を記憶してからゲッタリングを行い、ゲッタリング直後の直列振動抵抗値との変化の割合を算出し、この変化の割合を予め設定した値と比較することで判断してもよい。
なお、切断工程(S100)を行って個々の圧電振動子1に小片化した後に、微調工程(S90)を行う工程順序でも構わない。但し、上述したように、微調工程(S90)を先に行うことで、ウエハ体60の状態で微調を行うことができるので、複数の圧電振動子1をより効率良く微調することができる。よって、スループットの向上化を図ることができるので好ましい。
しかも、クロムは耐食性が優れている上に、酸素と結合し易いので、ゲッタリング工程の際、ゲッター材34が加熱されて蒸発したときに主に酸素からなるキャビティC内のガスを吸収し易く、ゲッタリング効果が高い。つまり、アルミニウムで形成していた従来のゲッター材と同等或いはそれ以上のゲッタリング効果を期待することができる。このため、キャビティC内の真空度を依然として短時間で向上させることができるので、圧電振動子1を効率良く製造することができる。
本実施形態の発振器100は、図14に示すように、圧電振動子1を、集積回路101に電気的に接続された発振子として構成したものである。この発振器100は、コンデンサ等の電子部品102が実装された基板103を備えている。基板103には、発振器用の上記集積回路101が実装されており、この集積回路101の近傍に、圧電振動子1が実装されている。これら電子部品102、集積回路101及び圧電振動子1は、図示しない配線パターンによってそれぞれ電気的に接続されている。なお、各構成部品は、図示しない樹脂によりモールドされている。
また、集積回路101の構成を、例えば、RTC(リアルタイムクロック)モジュール等を要求に応じて選択的に設定することで、時計用単機能発振器等の他、当該機器や外部機器の動作日や時刻を制御したり、時刻やカレンダー等を提供したりする機能を付加することができる。
無線部117は、音声データ等の各種データを、アンテナ125を介して基地局と送受信のやりとりを行う。音声処理部118は、無線部117又は増幅部120から入力された音声信号を符号化及び複号化する。増幅部120は、音声処理部118又は音声入出力部121から入力された信号を、所定のレベルまで増幅する。音声入出力部121は、スピーカやマイクロフォン等からなり、着信音や受話音声を拡声したり、音声を集音したりする。
なお、呼制御メモリ部124は、通信の発着呼制御に係るプログラムを格納する。また、電話番号入力部122は、例えば、0から9の番号キー及びその他のキーを備えており、これら番号キー等を押下することにより、通話先の電話番号等が入力される。
なお、通信部114の機能に係る部分の電源を、選択的に遮断することができる電源遮断部126を備えることで、通信部114の機能をより確実に停止することができる。
本実施形態の電波時計130は、図16に示すように、フィルタ部131に電気的に接続された圧電振動子1を備えたものであり、時計情報を含む標準の電波を受信して、正確な時刻に自動修正して表示する機能を備えた時計である。
日本国内には、福島県(40kHz)と佐賀県(60kHz)とに、標準の電波を送信する送信所(送信局)があり、それぞれ標準電波を送信している。40kHz若しくは60kHzのような長波は、地表を伝播する性質と、電離層と地表とを反射しながら伝播する性質とを併せもつため、伝播範囲が広く、上述した2つの送信所で日本国内を全て網羅している。
アンテナ132は、40kHz若しくは60kHzの長波の標準電波を受信する。長波の標準電波は、タイムコードと呼ばれる時刻情報を、40kHz若しくは60kHzの搬送波にAM変調をかけたものである。受信された長波の標準電波は、アンプ133によって増幅され、複数の圧電振動子1を有するフィルタ部131によって濾波、同調される。
本実施形態における圧電振動子1は、上記搬送周波数と同一の40kHz及び60kHzの共振周波数を有する水晶振動子部138、139をそれぞれ備えている。
搬送波は、40kHz若しくは60kHzであるから、水晶振動子部138、139は、上述した音叉型の構造を持つ振動子が好適である。
また、上記実施形態では、ゲッター材34が、平面視において圧電振動片4を挟んで両側に対向配置されるように2つ形成されているとしたが、例えば平面視において圧電振動片4の外側一方にのみ隣接して形成されていても構わない。
また、上記実施形態では、ゲッター材形成工程と引き回し電極形成工程とを同時に行うものとしたが、別々のタイミングに行っても構わない。
また、上記実施形態では、音叉型の圧電振動片4を例に挙げて説明したが、音叉型に限られるものではない。例えば、厚み滑り振動片としても構わない。
また、上記実施形態では、圧電振動片4をバンプ接合したが、バンプ接合に限定されるものではない。例えば、導電性接着剤により圧電振動片4を接合しても構わない。但し、バンプ接合することで、圧電振動片4をベース基板2の上面から浮かすことができ、振動に必要な最低限の振動ギャップを自然と確保することができる。よって、バンプ接合することが好ましい。
ここで、計測を行うにあたって、本発明に係る圧電振動子としては、ゲッター材がクロムのみで形成され、このゲッター材の厚みが600Åのものを用いた。また、従来の圧電振動子としては、ゲッター材がアルミニウムのみで形成され、このゲッター材の厚みが1100Åのものを用いた。つまり、本発明に係る圧電振動子のゲッター材には、従来の圧電振動子のゲッター材より厚みが薄いものを用いた。
そして、本発明に係る圧電振動子及び従来の圧電振動子について、このゲッター材の構成以外の点において条件を合わせて、それぞれの圧電振動子を同じ回数だけゲッタリングし、ゲッタリング前後のR1値を比較した。
この結果によれば、本発明に係る圧電振動子では、ゲッター材の厚みが従来の圧電振動子のゲッター材の厚みより薄いにも関わらず、従来のものよりゲッタリング前後のR1値の減少量が大きいことが確認できた。つまり、ゲッター材をクロムで形成することで、アルミニウムで形成する従来の場合以上のゲッタリング効果を得ることができるのを確認できた。
Claims (9)
- 互いに接合され、間にキャビティが形成されたベース基板及びリッド基板と、前記ベース基板の下面に形成された外部電極と、前記キャビティ内に収容されるように前記ベース基板の上面に形成された内部電極と、前記ベース基板を貫通するように形成され、前記外部電極と前記内部電極とを電気的に接続する貫通電極と、前記内部電極に電気的に接続された状態で前記キャビティ内に収容された圧電振動片と、前記キャビティ内に形成されたゲッター材と、を備える圧電振動子を製造する方法であって、
前記ゲッター材を、クロム若しくはクロムを主成分とする金属材料で形成することを特徴とする圧電振動子の製造方法。 - 請求項1に記載の圧電振動子の製造方法であって、
前記ゲッター材を、前記ベース基板の上面に形成する。 - 請求項2に記載の圧電振動子の製造方法であって、
前記内部電極を、前記ゲッター材と同じ材料で、前記ゲッター材と同時に形成する。 - 互いに接合され、間にキャビティが形成されたベース基板及びリッド基板と
前記ベース基板の下面に形成された外部電極と
前記キャビティ内に収容されるように前記ベース基板の上面に形成された内部電極と
前記ベース基板を貫通するように形成され、前記外部電極と前記内部電極とを電気的に接続する貫通電極と
前記内部電極に電気的に接続された状態で前記キャビティ内に収容された圧電振動片と
クロム若しくはクロムを主成分とする金属材料で前記キャビティ内に形成されたゲッター材と
を備えることを特徴とする圧電振動子。 - 請求項4に記載の圧電振動子であって、
前記ゲッター材は、前記ベース基板の上面に形成されている。 - 請求項5に記載の圧電振動子であって、
前記内部電極は、前記ゲッター材と同じ材料で、前記ゲッター材と同時に形成されたものである。 - 請求項4から6の何れか1項に記載の圧電振動子が、発振子として集積回路に電気的に接続されていることを特徴とする発振器。
- 請求項4から6の何れか1項に記載の圧電振動子が、計時部に電気的に接続されていることを特徴とする電子機器。
- 請求項4から6の何れか1項に記載の圧電振動子が、フィルタ部に電気的に接続されていることを特徴とする電波時計。
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PCT/JP2008/065250 WO2010023731A1 (ja) | 2008-08-27 | 2008-08-27 | 圧電振動子、発振器、電子機器及び電波時計、並びに圧電振動子の製造方法 |
CN2008801319229A CN102204090A (zh) | 2008-08-27 | 2008-08-27 | 压电振动器、振荡器、电子设备、电波钟以及压电振动器的制造方法 |
JP2010526453A JP5128671B2 (ja) | 2008-08-27 | 2008-08-27 | 圧電振動子、発振器、電子機器及び電波時計、並びに圧電振動子の製造方法 |
TW098123909A TW201014168A (en) | 2008-08-27 | 2009-07-15 | Piezoelectric vibrator, oscillator, electronic apparatus and radio clock, and manufacturing method of piezoelectric vibrator |
US13/035,468 US8514029B2 (en) | 2008-08-27 | 2011-02-25 | Piezoelectric vibrator, oscillator, electronic equipment and radio-controlled timepiece, and method of manufacturing piezoelectric vibrator |
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JP2011188308A (ja) * | 2010-03-09 | 2011-09-22 | Nippon Dempa Kogyo Co Ltd | 圧電振動子及び圧電振動子の製造方法 |
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CN102197586B (zh) * | 2008-08-27 | 2014-03-05 | 精工电子水晶科技股份有限公司 | 压电振动器、振荡器、电子设备、电波钟以及压电振动器的制造方法 |
JP6155551B2 (ja) * | 2012-04-10 | 2017-07-05 | セイコーエプソン株式会社 | 電子デバイス、電子機器および電子デバイスの製造方法 |
JP2014032137A (ja) * | 2012-08-06 | 2014-02-20 | Seiko Epson Corp | 振動片、電子デバイスおよび電子機器 |
WO2014129666A1 (ja) * | 2013-02-25 | 2014-08-28 | 京セラ株式会社 | 電子部品収納用パッケージおよび電子装置 |
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US8514029B2 (en) | 2013-08-20 |
TW201014168A (en) | 2010-04-01 |
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