JP2012235387A - Manufacturing method of piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a piezoelectric device which does not produce a gas and an air bubble inside a glass sealing material and has excellent vibration characteristics.SOLUTION: A manufacturing method of a piezoelectric device comprises: a step (S10) of preparing a piezoelectric vibration piece which vibrates when a voltage is applied; steps (S111, S12) of preparing a first plate and a second plate which store the piezoelectric vibration piece; a step (S112) of disposing a glass sealing material having a prescribed transition point in the first plate or the second plate; a first heating step (S14) of heating the glass sealing material to a transpiration temperature at which a binder and a solvent transpires; a second heating step (S15) of heating the glass sealing material to a temperature higher than the transpiration temperature and lower than a temperature at which a part of a glass component crystallizes after the first heating step; and a bonding step (S17) of bonding the first plate and the second plate with the glass sealing material.

Description

  The present invention relates to a method for manufacturing a surface-mount type piezoelectric device.

  As a piezoelectric device such as a piezoelectric vibrator, a surface mount type (SMD) type package is mainly used. The piezoelectric device is hermetically sealed in the package for vibration stabilization.

  For example, in the method for manufacturing a piezoelectric device disclosed in Patent Document 1, a pre-process for a package and a lid, a joining step for joining a piezoelectric vibrating piece to a package, and a lid sealing step for sealing the lid and the package Including. The pre-process of the package and the lid includes a sealing material sintering process, and the sealing material is sintered at a temperature of about 320 ° C. in the sealing material sintering process.

JP 2004-172752 A

  However, in the piezoelectric device manufacturing method disclosed in Patent Document 1, when the sealing material is sintered at a temperature of about 320 ° C. higher than the transition point of the sealing material in the sealing material sintering step, the inside of the sealing material Gas and bubbles are generated. Thereby, the pattern of a sealing material collapses. That is, for example, if the package and the lid are sealed in a foamed state, vacuum sealing cannot be performed, which may affect the vibration characteristics of the piezoelectric vibrating piece.

  An object of the present invention is to provide a method of manufacturing a piezoelectric device having good vibration characteristics without generating gas or bubbles inside a sealing material.

  A method of manufacturing a piezoelectric device according to a first aspect includes a step of preparing a piezoelectric vibrating piece that vibrates by application of a voltage, a step of preparing a first plate and a second plate that house the piezoelectric vibrating piece, a glass component, a binder, A step of placing a glass sealant containing a solvent and having a predetermined transition point on the first plate or the second plate, a first heating step of heating the glass sealant to a transpiration temperature at which the binder and solvent evaporate, After the first heating step, the glass sealing material is glass-sealed, the second heating step for heating the glass sealing material to a temperature higher than the transpiration temperature and lower than the temperature at which part of the glass component crystallizes, and the first plate and the second plate. A joining step of joining with a material.

  A method for manufacturing a piezoelectric device according to a second aspect includes a step of preparing a piezoelectric plate including a piezoelectric vibrating piece that vibrates by application of a voltage and a frame surrounding the piezoelectric vibrating piece, and is bonded to one main surface of the piezoelectric plate frame. Preparing a first plate, a step of preparing a second plate to be bonded to the other main surface of the frame of the piezoelectric plate, a glass plate, a binder, and a solvent. A step of arranging a glass sealing material having a predetermined transition point on the other main surface or the second plate of the plate and the frame, and a first heating step of heating the glass sealing material to a transpiration temperature at which the binder and solvent evaporate. And after the first heating step, the second heating step, the first plate, the piezoelectric plate and the second plate until the glass sealing material is higher than the transpiration temperature and lower than the temperature at which a part of the glass component is crystallized. A bonding step of bonding with a glass sealing material.

  In the piezoelectric device manufacturing method according to the third aspect, the first heating step heats the glass sealing material to 110% to 115% of the transition point, and the second heating step sets the glass sealing material to 125% of the transition point. Heat to ~ 133%.

  In the piezoelectric device manufacturing method according to the fourth aspect, the first plate includes a plurality of lid portions, the second plate includes a plurality of base portions, and the piezoelectric vibrating piece is accommodated in a package including the lid portion and the base portion. .

  In the piezoelectric device manufacturing method according to the fifth aspect, the first plate includes a plurality of lid portions, the second plate includes a plurality of base portions, the piezoelectric plate includes a plurality of piezoelectric vibrating pieces and a frame, and the piezoelectric vibrating piece. Is housed in a package comprising a lid portion, a frame body and a base portion.

In the piezoelectric device manufacturing method according to the sixth aspect, the transition point is 295 ° C.
In the piezoelectric device manufacturing method according to the seventh aspect, in the bonding step, the glass sealing material is heated to 120% to 125% of the transition point and bonded.

  The present invention provides a method for manufacturing a piezoelectric device having good vibration characteristics without generating gas or bubbles inside the sealing material.

2 is an exploded perspective view of a first crystal resonator 100. FIG. It is AA sectional drawing of FIG. 3 is a flowchart showing a method for manufacturing the first crystal unit 100. It is a top view of quartz wafer 10W. It is a top view of the base wafer 12W. It is a top view of the lid wafer 11W. It is a figure for demonstrating the temporary baking of a 1st heating stage, and 1st temperature is 330 degreeC. It is a figure for demonstrating the temporary baking of a 1st heating step, and 1st temperature is 340 degreeC. It is a figure for demonstrating temporary baking of a 1st heating stage, and 1st temperature is 350 degreeC. It is a figure for demonstrating temporary baking of a 1st heating stage, and 1st temperature is 360 degreeC. It is a figure for demonstrating the temporary baking of a 2nd heating step, 1st temperature is 330 degreeC and 2nd temperature is 350 degreeC. It is a figure for demonstrating the temporary baking of a 2nd heating step, 1st temperature is 330 degreeC and 2nd temperature is 370 degreeC. It is a figure for demonstrating temporary baking of a 2nd heating step, 1st temperature is 330 degreeC and 2nd temperature is 390 degreeC. It is a figure for demonstrating the temporary baking of a 2nd heating step, 1st temperature is 330 degreeC and 2nd temperature is 410 degreeC. 4 is an exploded perspective view of a second crystal resonator 200. FIG. It is BB sectional drawing of FIG. 5 is a flowchart showing a method for manufacturing the second crystal unit 200. It is a top view of quartz wafer 20W. It is a top view of the base wafer 22W.

  In this specification, an AT-cut crystal vibrating piece is used as the piezoelectric vibrating piece. In other words, the AT-cut quartz crystal vibrating piece is inclined by 35 degrees 15 minutes from the Z axis to the Y axis centering on the X axis with respect to the Y axis of the crystal axis (XYZ). Therefore, new tilted axes are used as the Y ′ axis and the Z ′ axis with reference to the X-axis direction of the AT-cut quartz crystal vibrating piece. That is, in this embodiment, the longitudinal direction of the crystal resonator as a piezoelectric device is the X-axis direction, the height direction of the crystal resonator is the Y′-axis direction, and the direction perpendicular to the X-axis direction and the Y′-axis direction is the Z′-axis. This will be described as a direction.

(First embodiment)
<Overall Configuration of First Crystal Resonator 100>
The overall configuration of the first crystal unit 100 will be described with reference to FIGS. 1 and 2.
1 is an exploded perspective view of the first crystal unit 100, and FIG. 2 is a cross-sectional view taken along line AA of FIG.

  As shown in FIG. 1, the first crystal unit 100 includes a lid portion 11 having a lid concave portion 111, a base portion 12 having a base concave portion 121, and a crystal vibrating piece 10 placed on the base portion 12. Prepare.

  The quartz crystal vibrating piece 10 is composed of an AT-cut quartz crystal piece 101, and a pair of excitation electrodes 102a and 102b are arranged to face both main surfaces near the center of the quartz crystal piece 101. Further, an extraction electrode 103a extending to the −X side of the bottom surface (−Y ′ side) of the crystal piece 101 is connected to the excitation electrode 102a, and + X on the bottom surface (−Y ′ side) of the crystal piece 101 is connected to the excitation electrode 102b. An extraction electrode 103b extending to the side is connected.

  Here, for the excitation electrode and the extraction electrode, for example, a chromium layer as a base is used, and a gold layer is used on the upper surface of the chromium layer. The chromium layer has a thickness of, for example, 0.05 μm to 0.1 μm, and the gold layer has a thickness of, for example, 0.2 μm to 2 μm.

  The base portion 12 has a first end face M1 formed around the base recess 121 on the surface (the surface on the + Y ′ side). Further, the base portion 12 is formed with castellations 122a and 122b extending in the Z′-axis direction when the through holes BH (see FIG. 5) are formed on both sides in the X-axis direction. Side electrodes 123a and 123b are formed on the castellations 122a and 122b, respectively. In addition, a connection electrode 124 a electrically connected to the side electrode 123 a is formed on the −X side of the first end face M <b> 1 of the base portion 12. Similarly, a connection electrode 124b that is electrically connected to the side electrode 123b is formed on the + X side of the first end face M1 of the base portion 12. Further, the base 12 has a pair of mounting terminals 125a and 125b electrically connected to the side electrodes 123a and 123b on the mounting surface (mounting surface of the crystal unit) M3. Here, the side electrode, the connection electrode, and the mounting terminal of the base portion 12 have the same configuration as the excitation electrode and the extraction electrode of the crystal vibrating piece 10.

  As shown in FIG. 2, the length of the base recess 121 in the X-axis direction is shorter than the length of the quartz crystal vibrating piece 10 in the X-axis direction. For this reason, when the crystal vibrating piece 10 is placed on the base portion 12 with the conductive adhesive 13, both ends of the crystal vibrating piece 10 in the X-axis direction are placed on the first end face M <b> 1 of the base portion 12. At this time, the extraction electrodes 103a and 103b of the crystal vibrating piece 10 are electrically connected to the connection electrodes 124a and 124b of the base portion 12, respectively. Thereby, the mounting terminals 125a and 125b are electrically connected to the excitation electrodes 102a and 102b via the side electrodes 123a and 123b, the connection electrodes 124a and 124b, the conductive adhesive 13, and the extraction electrodes 103a and 103b, respectively. That is, when an alternating voltage (a potential that alternates between positive and negative) is applied to the mounting terminals 125a and 125b, the quartz crystal vibrating piece 10 vibrates in thickness.

  As shown in FIGS. 1 and 2, the first crystal resonator 100 forms a cavity CT for housing the crystal resonator element 10 by the lid recess 111 of the lid portion 11 and the base recess 121 of the base portion 12. The cavity CT is filled with an inert gas or hermetically sealed in a vacuum state.

  The lid portion 11 has a second end face M <b> 2 formed around the lid recess 111 on the −Y ′ side. Further, the second end face M2 of the lid portion 11 and the first end face M1 of the base portion 12 are joined together by, for example, a low melting point glass LG as a sealing material.

  The low melting point glass LG includes vanadium-based glass having a transition point around 295 ° C. and a softening point around 350 ° C. Generally, when the amount of a metal such as vanadium is reduced, the transition point and the softening point are increased. This vanadium-based glass is in the form of a paste obtained by adding a binder and a solvent to a glass component (low melting glass powder). This vanadium-based glass is bonded to other members by being solidified after being melted. The transition point of vanadium-based glass is lower than the transition point of the lid portion 11 and the base portion 12 formed of a crystal material or glass, and this vanadium-based glass is reliable in terms of hermeticity at the time of bonding, water resistance and moisture resistance. High nature. The vanadium glass prevents moisture in the air from entering the cavity CT and lowering the degree of vacuum in the cavity CT. Furthermore, the thermal expansion coefficient of vanadium glass can be flexibly controlled by controlling the glass structure.

  Further, the length of the lid recess 111 is larger than the length of the quartz crystal resonator element 10 and the length of the base recess 121. Therefore, as shown in FIG. 2, the low-melting glass LG joins the lid portion 11 and the base portion 12 outside the first end face M <b> 1 of the base portion 12 (width is about 300 μm).

<Method for Manufacturing First Crystal Resonator 100>
FIG. 3 is a flowchart showing a method for manufacturing the first crystal unit 100. In FIG. 3, the manufacturing step S10 of the quartz crystal vibrating piece 10, the manufacturing step S11 of the lid portion 11, and the manufacturing step S12 of the base portion 12 can be performed separately and in parallel. 4 is a plan view of the quartz wafer 10W, FIG. 5 is a plan view of the base wafer 12W, and FIG. 6 is a plan view of the lid wafer 11W.

In step S10, the crystal vibrating piece 10 is manufactured. Step S10 includes steps S101 to S103.
In step S101, as shown in FIG. 4, the outer shape of the plurality of crystal vibrating pieces 10 is formed on the uniform crystal wafer 10W by etching. Here, each crystal vibrating piece 10 is connected to the crystal wafer 10 </ b> W by the connecting portion 104.

  In step S102, first, a chromium layer and a gold layer are sequentially formed on both surfaces and side surfaces of the quartz wafer 10W by sputtering or vacuum deposition. Then, a photoresist is uniformly applied on the entire surface of the metal layer. Thereafter, using an exposure apparatus (not shown), the patterns of the excitation electrodes 102a and 102b and the extraction electrodes 103a and 103b drawn on the photomask are exposed on the quartz wafer 10W. Next, the metal layer exposed from the photoresist is etched. As a result, as shown in FIG. 4, excitation electrodes 102a and 102b and extraction electrodes 103a and 103b are formed on both surfaces and side surfaces of the quartz wafer 10W.

  In step S103, the crystal vibrating pieces 10 are individually cut. In the cutting step, cutting is performed along a dashed line cut line CL shown in FIG. 4 using a dicing apparatus using a laser or a dicing apparatus using a cutting blade.

  In step S11, the base portion 12 is manufactured. Step S12 includes steps S111 and S112.

  In step S111, as shown in FIG. 5, the outer shapes of the plurality of base portions 12 are formed on the uniform base wafer 12W by etching. That is, hundreds to thousands of base recesses 121 are formed in the base wafer 12W. A base recess 121 is formed on the base wafer 12W by etching or machining, and a first end face M1 is formed around the base recess 121. At the same time, through holes BH with rounded corners are formed on both sides of each base portion 12 in the X-axis direction so as to penetrate the base wafer 12W. When the through hole BH is divided in half, one castellation 122a, 122b is formed.

  In step S122, the pair of mounting terminals 125a and 125b are formed on both sides in the X-axis direction of the mounting surface M3 of the base portion 12 by the sputtering and etching method described in step S102 as shown in FIG. At the same time, side electrodes 123a and 123b are formed in the through hole BH, and connection electrodes 124a and 124b are formed on the second end surface M2.

  In step S12, the lid part 11 is manufactured. Step S12 includes steps S1211 to S125.

  In step S121, as shown in FIG. 6, the outer shape of the plurality of lid portions 11 is formed on the uniform lid wafer 11W by etching. That is, hundreds to thousands of lid recesses 111 are formed in the lid wafer 11W. A lid recess 111 is formed on the lid wafer 11W by etching or machining, and a first end face M1 is formed around the lid recess 111.

  In step S122, as shown in FIG. 6, the paste-like low melting point glass LG is printed on the second end face M2 of the lid wafer 11W by screen printing.

Steps S123 to S125 are preliminary baking steps for the low-melting glass LG.
In step S123, the low-melting glass LG is heated to the first temperature as the first heating stage of the preliminary firing step of the low-melting glass LG. Here, when the transition point of the low melting point glass LG is 295 ° C., the first temperature is preferably 110% to 115% of the transition point. That is, it is 325 ° C. to 340 ° C.

  Hereinafter, an experiment relating to the first temperature in the first heating stage will be described with reference to FIGS. FIG. 7A is a temperature change graph of the low-melting glass LG, and FIG. 7B is a photograph of the low-melting glass LG that has been heated to 330 ° C. and then cooled with a microscope. As shown in FIG. 7A, in the melting profile of the low-melting glass, the temperature of the low-melting glass LG was increased to 330 ° C. and heated for 30 minutes. FIG. 7B shows a state in which the binder and the solvent contained in the low-melting glass LG are removed and the gas and bubbles inside the low-melting glass LG are emitted. At this temperature, the glass component contained in the low-melting glass LG is not melted.

  FIG. 8A is a temperature change graph of the low-melting glass LG, and FIG. 8B is a photograph of the low-melting glass LG that has been heated to 340 ° C. and then cooled, observed with a microscope. As shown in FIG. 8A, in the melting profile of the low-melting glass, the temperature of the low-melting glass LG was increased to 340 ° C. and heated for 30 minutes. FIG. 8B shows a state in which the binder and solvent contained in the low-melting glass LG have been removed and the gas and bubbles inside the low-melting glass LG have been released. Even at this temperature, the glass component contained in the low-melting glass LG is not melted.

  FIG. 9A is a temperature change graph of the low-melting glass LG, and FIG. 9B is a photograph of the low-melting glass LG heated to 350 ° C. and then cooled with a microscope. As shown in FIG. 9A, in the melting profile of the low-melting glass, the temperature of the low-melting glass LG was increased to 350 ° C. and heated for 30 minutes. FIG. 9B shows a state in which the glass component contained in the low-melting glass LG is melted and many holes HE are formed from the binder and the solvent in the low-melting glass LG.

  FIG. 10A is a temperature change graph of the low-melting glass LG, and FIG. 10B is a photograph of the low-melting glass LG that has been heated to 360 ° C. and then cooled with a microscope. As shown in FIG. 10A, in the melting profile of the low-melting glass, the temperature of the low-melting glass LG was increased to 360 ° C. and heated for 30 minutes. FIG. 10B shows a state in which smaller bubbles are buried in the melted glass inside the low-melting glass LG, and larger bubbles are partially buried to leave holes HE.

  As can be seen from the above description and FIGS. 7 to 10, when the first temperature in the first heating stage of the pre-baking step is set to 330 ° C. to 340 ° C., the binder and the solvent can be efficiently evaporated. On the other hand, when the temperature is 350 ° C. or higher, the glass component starts to melt while the binder and the solvent are evaporated. For this reason, there is a possibility that the binder HE and the solvent gas accumulate inside the melted glass, and the holes HE remain on the surface of the low melting point glass LG. If bubbles remain in the low-melting glass and pores remain on the surface, it is necessary to remove the bubbles and the like over a long heating time in the bonding step (S14) at the third temperature, which is a subsequent step. For this reason, the time of a joining process becomes long and manufacturing efficiency deteriorates. From the above, the first temperature is preferably set to 330 ° C to 340 ° C.

  In step S124, the low melting point glass LG is heated from the first temperature to the second temperature as the second heating stage of the preliminary baking step of the low melting point glass LG. Here, when the transition point of the low melting point glass LG is 295 ° C., the second temperature is preferably 125% to 133% of the transition point. That is, it is 370 degreeC-390 degreeC.

  Hereinafter, an experiment relating to the second temperature in the second heating stage will be described with reference to FIGS. Moreover, in FIGS. 11-14, the 1st heating stage of a temporary baking process is demonstrated as 330 degreeC. FIG. 11A is a temperature change graph of the low-melting glass LG, and FIG. 11B is a photograph of the low-melting glass LG heated to 350 ° C. as the second temperature and then cooled with a microscope. As shown in FIG. 11 (a), the melting profile of the low-melting glass is such that the temperature of the low-melting glass LG is first raised to 330 ° C. of the first temperature and heated for 30 minutes, and then raised to 350 ° C. of the second temperature. And heated for 10 minutes. Further, in FIG. 11B, the gas is almost eliminated from the binder and the solvent, but the glass HE is not melted somewhat and the hole HE is formed.

  FIG. 12A is a temperature change graph of the low-melting glass LG, and FIG. 12B is a photograph of the low-melting glass LG that has been heated to 370 ° C. as the second temperature and then cooled with a microscope. As shown in FIG. 12 (a), the melting profile of the low-melting glass is such that the temperature of the low-melting glass LG is first raised to 330 ° C. of the first temperature and heated for 30 minutes, and then raised to 370 ° C. of the second temperature. And heated for 10 minutes. Moreover, in FIG.12 (b), it is the state in which the small hole HE remains without the glass component melt | dissolving somewhat.

  FIG. 13A is a temperature change graph of the low-melting glass LG, and FIG. 13B is a photograph of the low-melting glass LG that has been heated to 390 ° C. as the second temperature and then cooled with a microscope. As shown in FIG. 13 (a), the melting profile of the low-melting glass is such that the temperature of the low-melting glass LG is first raised to 330 ° C. of the first temperature and heated for 30 minutes, and then raised to 390 ° C. of the second temperature. And heated for 10 minutes. Further, in FIG. 13B, there is almost no hole.

  FIG. 14A is a temperature change graph of the low-melting glass LG, and FIG. 14B is a photograph of the low-melting glass LG heated to 410 ° C. as the second temperature and then cooled with a microscope. As shown in FIG. 14 (a), the melting profile of the low-melting glass is such that the temperature of the low-melting glass LG is first raised to 330 ° C. of the first temperature and heated for 30 minutes, and then raised to 410 ° C. of the second temperature. And heated for 10 minutes. In FIG. 14B, the bubbles are removed and the holes are almost filled, but a part of the glass component of the low-melting glass LG is crystallized. A small glass component crystallized can be seen at the location indicated by CS. Crystallization of the glass component reduces the bonding strength of the low-melting glass LG.

  As can be seen from the above description and FIGS. 11 to 14, the second temperature in the second heating stage of the pre-baking step is preferably 370 ° C. to 390 ° C. That is, if the temperature is lower than 370 ° C., the hole HE from which bubbles are removed remains, and if the temperature is higher than 390 ° C., a part of the glass component of the low-melting glass LG may be crystallized to lower the bonding strength.

  Returning to FIG. 3, in step S125, the low-melting glass LG heated to the second temperature in the second heating stage of the pre-baking process is cooled to room temperature. Thereby, the degassed and defoamed low melting point glass LG is arranged on the lid wafer 11W.

  In step S <b> 13, the crystal vibrating piece 10 manufactured in step S <b> 10 is placed on the first end face M <b> 1 of the base portion 12 with the conductive adhesive 13. At this time, the crystal resonator element 10 is positioned at the first end surface of the base portion 12 so that the lead electrodes 103a and 103b of the crystal resonator element 10 and the connection electrodes 124a and 124b formed on the first end surface M1 of the base portion 12 are aligned. Mounted on M1. (See FIG. 2).

  In step S14, the lid wafer 11W and the base wafer 12W are pressurized while the low melting point glass LG is again heated to the third temperature. Thereafter, the low melting point glass LG is cooled to room temperature. As a result, the low-melting glass LG is securely bonded to the lid wafer 11W and the base wafer 12W. Since the low melting point glass LG has already been pre-fired in the absence of gas or the like, the joining process is completed in a short time. Here, the third temperature is 120% to 125% of the transition point (295 ° C.), that is, 360 ° C. to 375 ° C.

  In step S15, the bonded lid wafer 11W and base wafer 12W are individually cut. In the cutting step, the first crystal unit 100 is unitized along the one-dot chain line scribe line SL shown in FIGS. 5 and 6 by using a dicing apparatus using a laser or a dicing apparatus using a cutting blade. As a piece. Thereby, hundreds to thousands of first crystal units 100 are manufactured.

  In the method for manufacturing the first crystal unit 100, the low melting point glass LG is disposed on the lid wafer 11W, but may be disposed on the base wafer 12W.

(Second Embodiment)
<Overall Configuration of Second Crystal Resonator 200>
The overall configuration of the second crystal unit 200 will be described with reference to FIGS. 15 and 16. 15 is an exploded perspective view of the second crystal unit 200, and FIG. 16 is a cross-sectional view taken along the line BB of FIG.

  As shown in FIG. 15, the second crystal unit 200 includes a lid portion 21 having a lid recess 211, a base portion 22 having a base recess 221, and a crystal frame 20 sandwiched between the lid portion 21 and the base portion 22. With.

  As shown in FIGS. 1 and 2, the crystal frame 20 is formed of an AT-cut quartz material and has a + Y′-side surface Me and a −Y′-side back surface Mi. The crystal frame 20 includes a crystal vibrating piece 201 and a frame body 207 surrounding the crystal vibrating piece 201. A through opening 206 that penetrates from the front surface Me to the back surface Mi is formed between the crystal vibrating piece 201 and the frame body 207. Portions where the through opening 206 is not formed are connecting portions 208 a and 208 b that connect the crystal vibrating piece 201 and the frame body 207. Here, the connecting portion 208 a is connected to the −X axis side of the crystal vibrating piece 201, and the connecting portion 208 b is connected to the + X axis side of the crystal vibrating piece 201.

  At four corners of the crystal frame 20 in the X-axis direction, castellations 204a and 204b when the through holes CH (see FIG. 18) are formed are formed. Specifically, a pair of castellations 204 a is formed on the −X axis side of the crystal frame 20, and a pair of castellations 204 b is formed on the + X axis side of the crystal frame 20.

  In the crystal frame 20, excitation electrodes 202 a and 202 b are respectively formed on the front surface Me and the back surface Mi of the crystal vibrating piece 201. In addition, extraction electrodes 203a and 203b extracted from the excitation electrodes 202a and 202b are formed to extend to the castellations 204a and 204b via the connecting portions 208a and 208b and the frame body 207. Specifically, the excitation electrode 202a is formed to extend to the castellation 204a via the connecting portion 208a and the frame 207, and the excitation electrode 202b is formed to extend to the castellation 204b via the connecting portion 208b and the frame 207. The The castellations 204a and 204b are formed with extraction electrodes 203a and 203b and side electrodes 205a and 205b that are respectively conductive. In addition, it is preferable that the side electrode 205a electrically conductive to the extraction electrode 203a on the front surface Me extends to the back surface Mi of the frame body 207 to form the electrode pad 205M. Similarly, it is preferable that the side electrode 205b conductive to the extraction electrode 203b on the back surface Mi extends to the surface Me of the frame body 207 to form the electrode pad 205M.

  The base portion 22 is made of glass or a quartz material, and has a first end face M1 on the outer periphery of the + Y ′ side face. At four corners of the base portion 22 in the X-axis direction, castellations 222a and 222b when the through holes BH (see FIG. 19) are formed are formed. Specifically, a pair of castellations 222 a is formed on the −X axis side of the base portion 22, and a pair of castellations 222 b is formed on the + X axis side of the base portion 22.

  In the base portion 22, a mounting terminal 225a is formed on the −X axis side of the mounting surface M3, and a mounting terminal 225b is formed on the + X axis side of the mounting surface M3. Further, a side electrode 223a that is conductive to the mounting terminal 225a is formed on the castellation 222a, and a side electrode 223b that is conductive to the mounting terminal 225b is formed on the castellation 222b. The side electrodes 223a and 223b preferably extend to the first end face M1 of the base portion 22 to form the electrode pads 223M.

  Here, for the excitation electrode, the extraction electrode, the side electrode, and the mounting terminal, for example, a chromium (Cr) layer is used as a base, and a gold (Au) layer is used on the upper surface of the chromium layer. The chromium layer has a thickness of, for example, 0.05 μm to 0.1 μm, and the gold layer has a thickness of, for example, 0.2 μm to 2 μm.

  The lid portion 21 is made of glass or quartz material, and has a second end face M2 on the outer periphery of the surface at the −Y ′ side. Furthermore, it has the lid recessed part 211 dented from the 2nd end surface M2.

  Further, the lid portion 21 and the crystal frame 20 and the crystal frame 20 and the base portion 22 are joined by the low melting point glass LG. As shown in FIG. 1, the low melting point glass LG is disposed in a region corresponding to the second end face M <b> 2 of the lid portion 21, the frame body 207 of the crystal frame 20, and the first end face M <b> 1 of the base portion 22. Further, the low melting point glass LG is not formed at a place where each castellation is formed.

<Method for Manufacturing Second Crystal Resonator 200>
FIG. 17 is a flowchart showing a method for manufacturing the second crystal unit 200. In FIG. 17, the manufacturing step T10 of the crystal frame 20, the manufacturing step T11 of the lid portion 21, and the manufacturing step T12 of the base portion 22 can be performed separately and in parallel. 18 is a plan view of the crystal wafer 20W, and FIG. 19 is a plan view of the base wafer 22W.

In step T10, the crystal frame 20 is manufactured. Step T10 includes steps T101 and T102.
In step T101, as shown in FIG. 18, the outer shape of the plurality of crystal frames 20 is formed on the uniform crystal wafer 20W by etching. That is, the through opening 206 penetrating the crystal wafer 20 </ b> W is formed so that the crystal vibrating piece 201, the connecting portions 208 a and 208 b and the frame body 207 are formed in each crystal frame 20. At the same time, circular through holes CH penetrating the quartz wafer 20W are formed at the four corners of each quartz frame 20. Here, when the through hole CH is divided into quarters, one castellation 204a, 204b (see FIG. 15) is obtained.

  In step T102, as shown in FIG. 18, excitation electrodes 202a and 202b and extraction electrodes 203a and 03b are formed on both surfaces of the quartz wafer 20W by sputtering and etching, and the side electrodes 205a and 205b are formed in the through holes CH of the quartz wafer 20W. 205b is formed.

In step T11, the base portion 12 is manufactured. Step T12 includes steps T111 to T113.
In step T111, as shown in FIG. 19, the outer shapes of the plurality of base portions 22 are formed on the uniform base wafer 22W by etching. That is, the base recess 221 and the through hole BH are formed by etching or machining.

  In step T112, mounting terminals 225a and 225b are formed on the mounting surface M3 by sputtering and etching, side electrodes 223a and 223b are formed in the through hole BH, and connection pads 223M are formed on the second end surface M2.

  In step T113, the paste-like low melting point glass LG is printed on the first end face M1 of the base wafer by screen printing.

In step T12, the lid part 21 is manufactured. Step T12 includes steps T121 and T122.
In step T111, the outer shape of the plurality of lid portions 21 is formed on the uniform lid wafer by etching (see FIG. 6).

  In step T112, paste-like low-melting glass LG is printed on the second end face M2 of the lid wafer by screen printing (see FIG. 6).

Steps T13 to T15 are pre-baking steps for the low-melting glass LG.
In Step T13, the low-melting glass LG is heated to the first temperature as the first heating stage of the temporary baking process of the low-melting glass LG printed on the lid wafer and the base wafer 22W. Here, when the transition point of the low melting point glass LG is 295 ° C., the first temperature is preferably 110% to 115% of the transition point. That is, it is 325 ° C. to 340 ° C.

  In Step T14, the low melting point glass LG is heated from the first temperature to the second temperature as the second heating stage of the preliminary baking step of the low melting point glass LG printed on the lid wafer and the base wafer 22W. Here, when the transition point of the low melting point glass LG is 295 ° C., the second temperature is preferably 125% to 133% of the transition point. That is, it is 370 degreeC-390 degreeC.

  In step T15, the low-melting glass LG heated to the second temperature in the second heating stage of the pre-baking process is cooled to room temperature. As a result, the degassed and defoamed low melting point glass LG is placed on the lid wafer and the base wafer 22W.

  In step T16, the lid wafer and the base wafer 22W are arranged on both sides of the quartz wafer 20W and pressed while heating the low melting point glass LG to the third temperature again. As a result, the low melting point glass LG is melted, and the lid wafer (see FIG. 6), the crystal wafer 20W, and the base wafer 22W are reliably bonded. Since the low melting point glass LG has already been pre-fired in the absence of gas or the like, the joining process is completed in a short time. Here, the third temperature is 120% to 125% of the transition point (295 ° C.), that is, 360 ° C. to 375 ° C.

  In step T17, the bonded lid wafer, crystal wafer 20W, and base wafer 22W are individually cut. In the cutting step, the second crystal unit 200 is divided into individual pieces along the one-dot chain line scribe line SL shown in FIGS. Thereby, hundreds to thousands of second crystal resonators 200 are manufactured.

  As described above, the optimal embodiment has been described in detail in the present specification. However, as will be apparent to those skilled in the art, the present invention can be implemented with various modifications and variations within the technical scope thereof. .

As a low melting point glass, for example, zinc oxide (PbO) contains a small amount of B ₂ O ₃ , Bi ₂ O ₃ , ZnO, PbF ₂ , CuO, TiO ₂ , Nb ₂ O ₃ , Fe ₂ O ₃ , CaO and the like. Low melting glass may be used. In addition, as the low melting point glass having less adverse effect on the environment not containing lead, for example, a low melting point glass such as Cu ₂ O—CuO—P ₂ O ₅ based low melting point glass or SiO—SnO—P ₂ O ₅ is used May be.

  For example, although an AT-cut quartz crystal vibrating piece has been described as an example in this specification, the present invention is also applicable to a tuning fork type quartz vibrating piece having a pair of vibrating arms. Furthermore, the present invention can be applied to a piezoelectric oscillator in which an IC incorporating an oscillation circuit is accommodated in a cavity in addition to a crystal resonator.

DESCRIPTION OF SYMBOLS 10, 201 ... Crystal vibrating piece, 10W, 20W ... Crystal wafer 11, 21 ... Lid part, 11W ... Lid wafer 12, 22 ... Base part, 12W, 22W ... Base wafer 20 ... Crystal frame 100, 200 ... Crystal oscillator 102a, 102b, 202a, 202b ... Excitation electrodes 103a, 103b, 203a, 203b ... Extraction electrodes 104 ... Connection parts 111, 211 ... Lid recesses, 121, 221 ... Base recesses 122a, 122b, 204a, 204b, 222a, 222b ... Castration 123a , 123b, 205a, 205b, 223a, 223b ... Side electrodes 124a, 124b ... Connection electrodes 125a, 125b, 225a, 225b ... Mounting terminals 206 ... Through openings 207 ... Frame bodies 208a, 208b ... Connections Part CT ... Cavity LG ... Low melting point glass SL ... Scribe line

Claims (7)

Preparing a piezoelectric vibrating piece that vibrates by application of a voltage;
Preparing a first plate and a second plate for housing the piezoelectric vibrating piece;
Including a glass component, a binder and a solvent, and placing a glass sealing material having a predetermined transition point on the first plate or the second plate;
A first heating step of heating the glass sealing material to a transpiration temperature at which the binder and solvent evaporate;
After the first heating step, the second heating step of heating the glass sealing material to a temperature higher than the transpiration temperature and lower than a temperature at which a part of the glass component is crystallized;
A bonding step of bonding the first plate and the second plate with the glass sealing material;
A method for manufacturing a piezoelectric device comprising: Preparing a piezoelectric plate including a piezoelectric vibrating piece that vibrates by application of a voltage and a frame surrounding the piezoelectric vibrating piece;
Preparing a first plate joined to one main surface of the frame of the piezoelectric plate;
Preparing a second plate to be joined to the other main surface of the frame of the piezoelectric plate;
Disposing a glass sealing material containing a glass component, a binder and a solvent and having a predetermined transition point on one main surface of the frame or the first plate, and on the other main surface of the frame or the second plate When,
A first heating step of heating the glass sealing material to a transpiration temperature at which the binder and solvent evaporate;
After the first heating step, the second heating step until the glass sealing material is higher than the transpiration temperature and lower than the temperature at which a part of the glass component is crystallized,
A bonding step of bonding the first plate, the piezoelectric plate, and the second plate with the glass sealing material;
A method for manufacturing a piezoelectric device comprising:   In the first heating step, the glass sealing material is heated to 110% to 115% of the transition point, and in the second heating step, the glass sealing material is heated to 125% to 133% of the transition point. A method for manufacturing a piezoelectric device according to claim 1 or 2. The first plate includes a plurality of lid portions,
The second plate includes a plurality of base portions,
The method for manufacturing a piezoelectric device according to claim 1, wherein the piezoelectric vibrating piece is accommodated in a package including the lid portion and the base portion. The first plate includes a plurality of lid portions,
The second plate includes a plurality of base portions,
The piezoelectric plate includes a plurality of the piezoelectric vibrating pieces and the frame,
The method for manufacturing a piezoelectric device according to claim 2, wherein the piezoelectric vibrating piece is housed in a package including the lid portion, the frame body, and the base portion.   The method for manufacturing a piezoelectric device according to any one of claims 1 to 5, wherein the transition point is 295 ° C.   The method for manufacturing a piezoelectric device according to any one of claims 1 to 6, wherein in the bonding step, the glass sealing material is heated to 120% to 125% of the transition point and bonded.