JP2012257158A - Manufacturing method of piezoelectric device and piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device having a base, which does not have through holes, and manufactured in a wafer unit, and to provide a manufacturing method of the piezoelectric device.SOLUTION: A piezoelectric device (100) includes: a rectangular base (12) having a first surface where a pair of external electrodes (125) is formed, a second surface which is located on the opposite side of the first surface and where a first recessed part (121) and a first joining surface (M1) located around the first recessed part are formed, and a pair of connection electrodes (124) connecting with the external electrodes from the first joining surface through a side surface connecting the first surface with the second surface; a piezoelectric vibration piece (10) having a pair of excitation electrodes connecting with the connection electrodes and held by the base; a lid (11) in which a second recessed part covering the piezoelectric vibration piece and a second joining surface (M2) located around the second recessed part (111) are formed; and an annular sealing material (LG) annularly disposed between the first joining surface and the second joining surface and sealing the base and the lid.

Description

  The present invention relates to a piezoelectric device manufacturing method and a piezoelectric device in which piezoelectric vibrating reeds are individually placed on a package formed of a lid wafer or a base wafer.

  As disclosed in Patent Document 1, a surface mounting piezoelectric device generally has an insulating base of alumina ceramic and a lid of glass or Kovar alloy fixed to an opening of the ceramic base. The ceramic base and the lid form a cavity, and the piezoelectric vibrating piece is accommodated in the cavity.

  Further, as shown in Patent Document 2, there is a surface-mount piezoelectric device in which the base is not ceramic but glass is used for cost reduction. The glass base and the lid are fixed with low melting point glass.

JP 2005-333037 A JP 2005-057520 A

  However, since the piezoelectric device disclosed in Patent Document 1 is ceramic-based and needs to be manufactured individually, it is not preferable from the viewpoint of cost reduction. The piezoelectric device disclosed in Patent Document 2 uses a glass base, but needs to be manufactured individually and is not suitable for mass production. Further, the piezoelectric device disclosed in Patent Document 2 needs to form a through hole in a glass base. Furthermore, in the piezoelectric device disclosed in Patent Document 2, it is necessary to form a connection electrode on the main surface of the glass base to be thicker than 30 μm so that the piezoelectric vibrating piece and the glass base do not come into contact with each other. For this reason, the manufacturing cost of the piezoelectric device of Patent Document 2 is high even if a glass base is used.

  Accordingly, the present invention provides a piezoelectric device that can be manufactured on a wafer-by-wafer basis and a base that does not have a through hole, and a method for manufacturing the piezoelectric device. Another object of the present invention is to provide a piezoelectric device having a thickness (several hundreds of nanometers) formed by sputtering or vacuum vapor deposition and a manufacturing method thereof.

  In the piezoelectric device of the first aspect, a first surface on which a pair of external electrodes are formed and a first joint surface around the first recess is formed on the opposite side of the first surface. A rectangular base having a pair of connection electrodes connected to an external electrode via a side surface connecting the first surface and the second surface from the two surfaces and the first bonding surface; and a pair of excitation electrodes connected to the connection electrode A piezoelectric vibrating piece that is held on the base, a second recess that covers the piezoelectric vibrating piece, a lid on which a second bonding surface around the second depression is formed, a first bonding surface, and a second bonding surface An annular sealing material that is annularly disposed between the base and the lid.

  In the piezoelectric device according to the second aspect, when viewed from the direction from the base to the lid, the outer periphery of the base is rectangular and the outer periphery of the lid is rectangular. Further, in the piezoelectric device, at least two corner portions of the rectangular first recess portion are projected to the center side of the first recess portion at the same height as the first joint surface, and a pair of connection electrodes are formed at the corner portions. ing. Further, in the piezoelectric device, the two corners of the first recess are formed on the same short side of the first recess, and the extraction electrode is extracted to the same short side of the piezoelectric vibrating piece.

  In the piezoelectric device according to the third aspect, the two corners are respectively formed on the short sides facing each other of the first recess, and the extraction electrodes are respectively drawn out on the short sides facing each other of the piezoelectric vibrating piece. In the piezoelectric device, the external electrode and the connection electrode are electrically connected via a castellation formed on a side surface connecting the first surface and the second surface. The piezoelectric device can also be applied to a tuning fork type piezoelectric vibrating piece and a vibrating piece including a mesa type or a convex type having a thickness at a center portion rather than a peripheral portion.

According to the manufacturing method of the present invention, a piezoelectric device can be manufactured at a reduced cost for each wafer. Further, the piezoelectric device does not contain harmful gas or moisture, and mass production is possible. Further, since the piezoelectric device of the present invention does not contain harmful gas or moisture, it vibrates or oscillates stably.

1 is an exploded perspective view of a first crystal resonator 100 according to a first embodiment. FIG. 3 is a perspective view of the first crystal resonator 100 according to the first embodiment after the first crystal vibrating piece 10 is placed on the first base 12 and before the lid portion 11 is joined to the first base 12. (A) is AA sectional drawing of FIG. FIG. 4B is a bottom view of the first crystal resonator 100. FIG. 3 is a flowchart showing the manufacture of the first crystal unit 100 of the first embodiment. It is a top view of quartz wafer 10W. It is a top view of the lid wafer 11W. It is a top view of the base wafer 12W. It is a disassembled perspective view of the 2nd crystal oscillator 110 of a 2nd embodiment. (A) is a BB cross-sectional view of the second crystal unit 110. FIG. 4B is a plan view of the second base plate 22 of the second crystal unit 110. It is a top view of the base wafer 22W. It is a disassembled perspective view of the 3rd crystal oscillator 120 of a 3rd embodiment. It is a top view of the base wafer 32W. It is a disassembled perspective view of the 4th crystal oscillator 130 of a 4th embodiment. It is a top view of the base wafer 42W.

(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.
FIG. 1 is an exploded perspective view of the first crystal unit 100. FIG. 2 is a perspective view of the first crystal resonator 100 of the first embodiment after the first crystal vibrating piece 10 is placed on the first base 12 and before the lid plate 11 is bonded to the first base 12. is there. FIG. 3A is a cross-sectional view of the first crystal unit 100 taken along the line AA, and FIG. 3B is a bottom view of the first crystal unit 100.

  An AT-cut first crystal vibrating piece 10 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). For this reason, in the first embodiment, the new tilted axes are used as the Y ′ axis and the Z ′ axis with reference to the axial direction of the AT-cut quartz crystal vibrating piece. That is, in the first embodiment, the longitudinal direction of the first crystal unit 100 is the X-axis direction, the height direction of the first crystal unit 100 is the Y′-axis direction, and the direction perpendicular to the X and Y′-axis directions is Z ′. Will be described. The same applies to the second to fourth embodiments.

  As shown in FIG. 1, the first crystal unit 100 includes a lid plate 11 having a lid recess 111, a first base 12 having a base recess 121, and a first crystal vibration placed on the first base 12. And a piece 10.

  The first crystal vibrating piece 10 is constituted by an AT-cut crystal piece 101, and a pair of excitation electrodes 102 a and 102 b are arranged to face both main surfaces near the center of the 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. The lead electrodes 103a and 103b have a connection region that is long in the Z′-axis direction in accordance with connection electrodes 124a and 124b described later.

  The first quartz-crystal vibrating piece 10 has a length L6 in the X-axis direction of about 2400 μm, a width W6 in the Z′-axis direction of about 1500 μm, and a height H6 in the Y′-axis direction is determined by the excitation frequency. Further, the excitation electrode 102 and the extraction electrode 103 are made of, for example, a chromium layer as a base, 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 first base 12 has a first end face M <b> 1 formed on the surface (+ Y ′ side face) around the base recess 121. The first base 12 is formed with base castellations 122a and 122b that bisect a base through hole BH1 (see FIG. 7) on both sides in the X-axis direction. Base side electrodes 123a and 123b (see FIG. 3A) are formed on the base castellations 122a and 122b, respectively. In addition, a connection electrode 124 a electrically connected to the base side surface electrode 123 a is formed on the −X side of the first end surface M 1 of the first base 12. Similarly, a connection electrode 124b electrically connected to the base side surface electrode 123b is formed on the + X side of the first end surface M1 of the first base 12. Further, the first base 12 has a pair of mounting terminals 125a and 125b electrically connected to the base side surface electrodes 123a and 123b on the mounting surface (mounting surface of the crystal resonator) (FIG. 3B). See).

  As shown in FIG. 2, the first base 12 has a length L1 in the X-axis direction of about 3200 μm, a width W1 in the Z′-axis direction of about 2500 μm, and a height H3 in the Y′-axis direction of about 300 μm. is there. The length W2 of the base castellations 122a and 122b in the Z ′ direction is about 1/3 to 1/2 of the width W1 of the first base 12, that is, about 800 to 1300 μm. The length W3 in the Z ′ direction of the connection electrodes 124a and 124b is about the same as the length W2 of the base castellations 122a and 122b, ie, about 700 to 1300 μm.

  As shown in FIG. 3, the length L5 of the base recess 121 in the X-axis direction is shorter than the length L6 of the first crystal vibrating piece 10 in the X-axis direction, and is about 2210 μm. The depth of the base recess 121 is about 40 μm. Furthermore, the base side electrode, the connection electrode, and the mounting terminal have the same configuration as the excitation electrode and the extraction electrode.

  That is, in the first crystal unit 100, the length L6 (2400 μm) of the first crystal resonator element 10 is larger than the length L5 (2210 μm) of the base recess 121. For this reason, when the first crystal vibrating piece 10 is placed on the first base 12 with the conductive adhesive 13, both ends in the X-axis direction of the first crystal vibrating piece 10 are placed on the first end face M 1 of the first base 12. Is done. At this time, as shown in FIG. 3A, the extraction electrodes 103a and 103b of the first quartz crystal vibrating piece 10 are electrically connected to the connection electrodes 124a and 124b of the first base 12, respectively. Accordingly, the mounting terminals 125a and 125b are electrically connected to the excitation electrodes 102a and 102b via the base 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 first quartz crystal vibrating piece 10 vibrates in thickness.

  Further, since the connection electrodes 124a and 124b of the first base 12 are formed wider (W3: 700 μm or more), when the first crystal vibrating piece 10 is bonded to the first base 12, the extraction electrodes 103a and 103b and the connection electrodes 124a and 124b can be connected in a wider area. Therefore, the extraction electrodes 103a and 103b and the connection electrodes 124a and 124b are more reliably electrically connected, and the wiring resistance is small.

  Further, as shown in FIG. 3B, four mounting terminals 125 are formed at the four corners of the mounting surface of the first base 12. Among them, the mounting terminals 125a and 125b are electrically connected to the base side surface electrodes 123a and 123b, respectively, and the other two mounting terminals 125 are used for grounding.

  As shown in FIG. 1 to FIG. 3, the first crystal resonator 100 forms a cavity CT for housing the first crystal resonator element 10 by the lid recess 111 of the lid plate 11 and the base recess 121 of the first base 12. . The cavity CT is filled with an inert gas or hermetically sealed in a vacuum state.

  The lid plate 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 plate 11 is connected to the first end face M1 of the first base 12 by, for example, a non-conductive low melting point glass LG.

  The low melting point glass LG includes lead-free vanadium-based glass that melts at 350 ° C. to 400 ° C. Vanadium-based glass is in the form of a paste with a binder and a solvent added, and is melted and then solidified to adhere to other members. The melting point of the vanadium-based glass is lower than the melting points of the lid plate 11 and the first base 12 made of crystal material or glass, and the vanadium-based glass is reliable in terms of airtightness and water / moisture resistance during bonding. Is expensive. 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.

  Like the first base portion 12, the lid plate 11 has a length L1 in the X-axis direction of about 3200 μm and a width W1 in the Z′-axis direction of about 2500 μm, but its height H2 in the Y′-axis direction is 450 μm. Degree. The length L4 of the lid recess 111 in the X-axis direction is longer than the length L6 of the first crystal vibrating piece 10 in the X-axis direction, and is about 2600 μm. The depth of the lid recess 111 is about 250 μm.

  That is, the length L4 (2600 μm) of the lid concave portion 111 is larger than the length L6 (2400 μm) of the first crystal vibrating piece 10 and the length L5 (2210 μm) of the base concave portion 121. Therefore, as shown in FIGS. 1 and 3A, the low-melting glass LG is formed on the outside of the first end face M1 of the first base 12 (with a width of about 300 μm), the lid plate 11 and the first base 12 Join.

<Method for Manufacturing First Crystal Resonator 100>
FIG. 4 is a flowchart showing the manufacture of the first crystal unit 100. In FIG. 4, the manufacturing step S10 of the first quartz crystal vibrating piece 10, the manufacturing step S11 of the lid plate 11, and the manufacturing step S12 of the first base 12 can be performed separately and in parallel. 5 is a plan view of the quartz wafer 10W, FIG. 6 is a plan view of the lid wafer 11W, and FIG. 7 is a plan view of the base wafer 12W.

In step S10, the first crystal vibrating piece 10 is manufactured. Step S10 includes steps S101 to S103.
In step S101, as shown in FIG. 5, the outer shape of the plurality of first crystal vibrating pieces 10 is formed on the uniform crystal wafer 10W by etching. Here, each first crystal vibrating piece 10 is connected to the crystal wafer 10 </ b> W by a 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, the pattern of the excitation electrode and the extraction electrode drawn on the photomask is exposed to the quartz wafer 10W using an exposure apparatus (not shown). Next, the metal layer exposed from the photoresist is etched. As a result, excitation electrodes 102a and 102b and extraction electrodes 103a and 103b are formed on both surfaces of the quartz wafer 10W as shown in FIG. 5 (see FIG. 1).

  In step S103, the first crystal vibrating piece 10 is individually cut. In the cutting step, cutting is performed along a dashed line cut line CL shown in FIG. 5 using a dicing apparatus using a laser or a dicing apparatus using a cutting blade.

In step S11, the lid plate 11 is manufactured. Step S11 includes steps S111 and S112.
In step S111, as shown in FIG. 6, hundreds to thousands of lid recesses 111 are formed on the lid wafer 11W of a quartz plate having a uniform thickness. A lid recess 111 is formed on the lid wafer 11W by wet etching or machining, and a second end face M2 is formed around the lid recess 111.

  In step S112, as shown in FIG. 6, the low melting point glass LG is printed on the second end face M2 of the lid wafer 11W by screen printing. Thereafter, the low-melting glass LG is temporarily cured to form a low-melting glass film on the second end face M2 of the lid wafer 11W.

In step S12, the first base 12 is manufactured. Step S12 includes steps S121 and S122.
In step S121, as shown in FIG. 7, hundreds to thousands of base recesses 121 are formed on a base wafer 12W of a quartz plate having a uniform thickness. 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, rounded rectangular base through holes BH1 are formed on both sides of each first base 12 in the X-axis direction so as to penetrate the base wafer 12W. When the base through hole BH1 is divided in half, one base castellation 122a, 122b (see FIG. 1) is obtained.

  In step S122, the mounting terminals 125 are formed at the four corners of the mounting surface of the first base 12 (the crystal resonator mounting surface) as shown in FIG. 7 by the same method as the sputtering and etching method described in step S102. Is done. At the same time, base side surface electrodes 123a and 123b are formed in the base through hole BH1, and connection electrodes 124a and 124b are formed on the first end surface M1 (see FIG. 1).

  In step S <b> 13, the individual first crystal vibrating pieces 10 manufactured in step S <b> 10 are placed on the first end face M <b> 1 of the first base 12 with the conductive adhesive 13. At this time, the first crystal vibrating piece 10 is in the first position so that the extraction electrodes 103a and 103b of the first crystal vibrating piece 10 and the connection electrodes 124a and 124b formed on the first end face M1 of the first base 12 are aligned. It is placed on the first end face M1 of the base 12. At this time, since the connection area between the extraction electrodes 103a and 103b and the connection electrodes 124a and 124b is large, the electrical connection can be made more reliably (see FIG. 2).

In step S14, the vibration frequency of each first crystal vibrating piece 10 is measured.
In step S15, the thickness of the excitation electrode 102a of the first crystal vibrating piece 10 is adjusted. Sputtering metal on the excitation electrode 102a increases the mass to lower the frequency, or reverse sputtering to sublimate the metal from the excitation electrode 102a to decrease the mass and increase the frequency. If the measurement result of the vibration frequency is within the predetermined range, it is not always necessary to adjust the vibration frequency.

  Several hundred to several thousand first crystal vibrating pieces 10 are placed on the base wafer 12W. After measuring the vibration frequency of one first crystal vibrating piece 10 in step S14, the vibration frequency of one first crystal vibrating piece 10 may be adjusted in step S15. This step is repeated for all the first crystal vibrating pieces 10 on the base wafer 12W. Further, after measuring the vibration frequency of all the first crystal vibrating pieces 10 on the base wafer 12W in step S14, the vibration frequency of the first crystal vibrating piece 10 may be adjusted one by one in step S15.

  In step S16, the low-melting glass LG is heated to pressurize the lid wafer 11W and the base wafer 12W. Then, the low melting point glass LG is cooled to room temperature. Thereby, the lid wafer 11W and the base wafer 12W are joined by the low melting point glass LG.

  In step S17, the bonded lid wafer 11W and base wafer 12W are individually cut. In the cutting process, the first crystal unit 100 is unitized along the one-dot chain line scribe line SL shown in FIGS. 6 and 7 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.

(Second Embodiment)
<Overall Configuration of Second Crystal Resonator 110>
The overall configuration of the second crystal unit 110 will be described with reference to FIGS.
FIG. 8 is an exploded perspective view of the second crystal unit 110 according to the second embodiment, FIG. 9A is a cross-sectional view taken along the line BB of the second crystal unit 110, and FIG. 2 is a plan view of the second base plate 22 of the quartz crystal vibrator 110, and FIG. 10 is a plan view of the base wafer 22W. The difference between the second crystal resonator 110 and the first crystal resonator 100 is that a second crystal resonator element 20 having a different extraction electrode shape is attached instead of the first crystal resonator element 10. A second base plate 22 is provided instead of the first base 12. The same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and differences will be described.

  As shown in FIG. 8, the second crystal unit 110 includes a lid plate 11 having a lid recess 111, a second base plate 22 having a base recess 221, and an AT cut placed on the second base plate 22. The second crystal vibrating piece 20 is provided.

  The second crystal vibrating piece 20 is constituted by an AT-cut crystal piece 201, and a pair of excitation electrodes 202 a and 202 b are arranged to face both main surfaces near the center of the crystal piece 201. The excitation electrode 202a is connected to an extraction electrode 203a extending to the −X side of the bottom surface (−Y ′ side) of the crystal piece 201, and + X on the bottom surface (−Y ′ side) of the crystal piece 201 is connected to the excitation electrode 202b. An extraction electrode 203b extending to the side is connected. The lead electrodes 203a and 203b are formed in a substantially square connection region in accordance with connection electrodes 224a and 224b described later. In addition, since pedestals 226a and 226c, which will be described later, are formed, the second crystal vibrating piece 20 can be shorter in the X-axis direction than the first crystal vibrating piece 10. For example, the length L6 of the second crystal vibrating piece 20 in the X-axis direction may be equal to the length L5 of the base recess 221 in the X-axis direction.

  The second base plate 22 has a first end face M1 formed on the surface (+ Y ′ side face) around the base recess 221. The base recess 221 includes pedestals 226a and 226c at two corners. The pedestals 226a and 226c protrude to the center side of the base recess 221 at the same height as the first end face M1. The pedestals 226a and 226c are substantially square when viewed from the Y′-axis direction. The sizes of the pedestals 226a and 226c are such that they do not overlap with the excitation electrode 202 of the second crystal vibrating piece 20 from the Y′-axis direction. A pair of connection electrodes 224 are formed in a substantially square shape on the surfaces (+ Y′-axis side) of the bases 226a and 226c.

  The second base plate 22 is formed with circular base through holes BH2 (see FIG. 10) at four corners, and then base castellations 222a, 222b, 222c, and 222d in which the circular base through holes BH2 are divided into four are formed. ing. Base side electrodes 223a and 223b (see FIGS. 8 and 9B) are formed on the base castellations 222a and 222c, respectively. Further, a connection electrode 224 a electrically connected to the base side surface electrode 223 a is formed on the −X side base 226 a of the first end face M 1 of the second base plate 22. Similarly, a connection electrode 224 b electrically connected to the base side surface electrode 223 b is formed on the base 226 c on the + X side of the first end surface M 1 of the second base plate 22. Further, the second base plate 22 has a pair of mounting terminals 225a and 225b (see FIG. 9) that are electrically connected to the base side electrodes 223a and 223b, respectively, on the mounting surface of the crystal resonator.

  As shown in FIG. 9A, the extraction electrodes 203a and 203b of the second crystal vibrating piece 20 are electrically connected to the connection electrodes 224a and 224b of the second base 22 through the conductive adhesive 13, respectively. . Since the bases 226a and 226c are formed, the area where the extraction electrodes 203a and 203b of the second crystal vibrating piece 20 are in contact with the connection electrodes 224a and 224b is smaller than that of the first crystal vibrating piece 10 of the first embodiment. Become. Therefore, the second crystal resonator element 20 is not limited to a flat AT cut, but may be a convex type whose center is thickened in a curved shape, or a mesa type whose center is thickened like a staircase. It becomes easy to do.

  Even if a large amount of the conductive adhesive 13 is applied by mistake, the excess conductive adhesive 13 may flow into the base recess 221 from the bases 226a and 226c and come into contact with the excitation electrode 202b of the second crystal vibrating piece 20. Absent.

<Method for Manufacturing Second Crystal Resonator 110>
The manufacturing method of the second crystal unit 110 is substantially the same as the flowchart described in the first embodiment. The second crystal resonator element 20 and the second base plate 22 of the second crystal resonator 110 will be additionally described with reference to the flowchart shown in FIG.

  In step S10, the second crystal vibrating piece 20 is manufactured. First, the external shape of the plurality of second crystal vibrating pieces 20 is formed on a crystal wafer (not shown) by etching. As shown in FIG. 8, excitation electrodes 202a and 202b and extraction electrodes 203a and 203b are formed on both surfaces of the quartz wafer. Thereafter, the second crystal vibrating piece 20 is individually cut using a dicing apparatus using a laser or a dicing apparatus using a cutting blade.

  In step S12, the second base plate 22 is manufactured. First, as shown in FIG. 10, hundreds to thousands of base recesses 221 are formed on a base wafer 22W of a quartz plate having a uniform thickness. At the same time, the second base plate 22 is formed with a first end face M1 around the base recess 221, and pedestals 226a and 226c are formed at two corners of the base recess 221, respectively. Round base through holes BH2 (see FIG. 10) are formed at the four corners of each second base plate 22 so as to penetrate the base wafer 22W. When the base through hole BH2 is divided into four, one base castellation 222a, 222b, 222c, 222d (see FIG. 8) is obtained. Thereafter, base side electrodes 223a and 223b are formed in the base through hole BH2 by the sputtering and etching method described in step S102 of FIG. 4, and connection electrodes 224a and 224b are formed on the bases 226a and 226c of the first end face M1. (See FIG. 8). As shown in FIGS. 9A and 9B, the second base plate 22 has mounting terminals 225 formed at the four corners of the mounting surface of the second base plate 22 (the crystal resonator mounting surface).

  In step S <b> 13, the second crystal vibrating piece 20 manufactured in step S <b> 10 is placed on the bases 226 a and 226 c of the second base plate 22 with the conductive adhesive 13. Subsequent processes are substantially the same as those in the flowchart (see FIG. 4) described in the first embodiment.

(Third embodiment)
<Overall Configuration of Third Crystal Resonator 120>
The overall configuration of the third crystal unit 120 will be described with reference to FIGS. 11 and 12.
FIG. 11 is an exploded perspective view of the third crystal unit 120 of the third embodiment, and FIG. 12 is a plan view of the base wafer 32W. The difference between the third crystal unit 120 and the second crystal unit 110 is that a third base plate 32 is provided instead of the second base plate 22 of the second crystal unit 110. The same components as those of the second embodiment are denoted by the same reference numerals, description thereof will be omitted, and differences will be described.

  The third base plate 32 has a first end face M1 formed on the surface (+ Y ′ side face) around the base recess 321. The base recess 321 includes pedestals 226a, 226b, 226c, and 226d at four corners. The bases 226a, 226b, 226c, and 226d protrude to the center side of the first end face M1 at the same height as the first joint surface, and a pair of connection electrodes 224 are formed on the bases 226a and 226c. Connection electrodes are not formed on the bases 226b and 226d.

  The third base plate 32 is formed with base castellations 222a, 222b, 222c, and 222d when base through holes BH2 (see FIG. 12) are formed at the four corners. Base side electrodes 223a and 223b (see FIGS. 11 and 12) are formed on the base castellations 222a and 222c, respectively. In addition, a connection electrode 224 a electrically connected to the base side surface electrode 223 a is formed on the −X side base 226 a of the first end face M 1 of the third base plate 32. Similarly, a connection electrode 224 b electrically connected to the base side surface electrode 223 b is formed on the base 226 c on the + X side of the first end face M 1 of the third base plate 32. Further, the third base plate 32 has a pair of mounting terminals 225a (see FIG. 11) and 225b (not shown) electrically connected to the base side electrodes 223a and 223b on the mounting surface of the crystal resonator. Yes.

The pedestals 226a, 226b, 226c, and 226d are substantially square when viewed from the Y′-axis direction. The sizes of the pedestals 226a and 226c are such that they do not overlap with the excitation electrode 202 of the second crystal vibrating piece 20 from the Y′-axis direction. If the pedestals 226a to 226d are not formed, the distance from the base castellations 222a to 222d to the corners of the base recess 321 is shortened, and the width (X-axis direction or Z′-axis direction) of the first end face M1 is narrow. Become. But,
Since the bases 226a to 226d are formed, the width of the first end face M1 can be increased, and the strength of the third base plate 32 is increased. Further, the low melting point glass LG can be formed wider, and the third crystal unit 120 is formed more airtight.

  The second crystal resonator element 20 is not limited to a flat plate AT cut, but may be a convex type whose center is thickened in a curved shape, or a mesa type whose center is thickened like a staircase. . Further, the length L6 in the X-axis direction of the second crystal vibrating piece 20 may be equal to the length L5 in the X-axis direction of the base recess 321.

<Method for Manufacturing Third Crystal Resonator 120>
The manufacturing method of the third crystal unit 120 is substantially the same as the flowchart (see FIG. 4) described in the first embodiment. FIG. 12 shows a base wafer 32W in which hundreds to thousands of third base plates 32 are formed. The third base plate 32 is formed with a first end face M1 around the base recess 321 and pedestals 226a, 226b, 226c and 226d are formed at four corners of the base recess 321. A connection electrode 224 a electrically connected to the base side electrode 223 a (see FIG. 11) is formed on the −X side base 226 a of the first end face M 1 of the third base plate 32. Similarly, a connection electrode 224 b that is electrically connected to the base side surface electrode 223 b is formed on the base 226 c on the + X side of the first end face M 1 of the third base plate 32.

(Fourth embodiment)
<Overall Configuration of Fourth Crystal Resonator 130>
The overall configuration of the fourth crystal unit 130 will be described with reference to FIGS. 13 and 14.
FIG. 13 is an exploded perspective view of the fourth crystal unit 130 of the fourth embodiment, and FIG. 14 is a plan view of the base wafer 42W. The difference between the fourth crystal resonator 130 and the second crystal resonator 110 is that a cantilever type third crystal resonator element 30 is mounted instead of the second crystal resonator element 20. Further, a fourth base plate 42 is provided instead of the second base plate 22. The same components as those of the second embodiment are denoted by the same reference numerals, description thereof will be omitted, and differences will be described.

  The third crystal vibrating piece 30 is constituted by an AT-cut crystal piece 301, and a pair of excitation electrodes 302 a and 302 b are arranged to face both main surfaces near the center of the crystal piece 301. The excitation electrode 302a is connected to an extraction electrode 303a extending to one end on the −Y ′ side of the bottom surface of the AT-cut crystal piece 301, and −Y ′ in the same direction on the bottom surface of the AT-cut crystal piece 301 is connected to the excitation electrode 301b. An extraction electrode 303b extending to the other corner on the side is connected. The extraction electrodes 303a and 303b are formed at one end in the X-axis direction. The extraction electrodes 303a and 303b of the third crystal vibrating piece 30 are bonded to the connection electrode 224a and the connection electrode 224b of the fourth base plate 42 by the conductive adhesive 13 (not shown).

  The fourth base plate 42 has a first end face M <b> 1 formed around the base recess 421 on the surface (the surface on the + Y ′ side). The base recess 421 includes pedestals 226a and 226b at two corners. The bases 226a and 226b protrude to the center side of the first end face M1 at the same height as the first joint surface, and a pair of connection electrodes are formed on the bases 226a and 226b.

  Base castellations 222a, 222b, 222c, and 222d when the base through holes BH2 (see FIG. 14) are formed are formed at the four corners of the fourth base plate. Base side electrodes 223a and 223b (see FIG. 13) are formed on the base castellations 222a and 222c, respectively. Further, a connection electrode 224 a electrically connected to the base side surface electrode 223 a is formed on the −X side base 226 a of the first end face M 1 of the second base plate 22. Similarly, a connection electrode 224b electrically connected to the base side surface electrode 223b through the connection electrode 424 is formed on the base 226b on the −X side of the first end face M1. Further, the fourth base plate 42 has a pair of mounting terminals 225a and 225b (not shown) electrically connected to the base side electrodes 223a and 223b on the mounting surface of the crystal resonator.

  The third quartz crystal vibrating piece 30 is not limited to a flat AT cut, but may be a convex type whose center is thickened in a curved shape, or a mesa type whose center is thickened like a staircase. . Further, the length L6 of the third crystal vibrating piece 30 in the X-axis direction may be equal to the length L5 of the base recess 421 in the X-axis direction.

<Method for Manufacturing Fourth Crystal Resonator 130>
The manufacturing method of the fourth crystal unit 130 is substantially the same as the flowchart described in the first embodiment (see FIG. 4). As shown in FIG. 14, hundreds to thousands of fourth base plates 42 are formed on the base wafer 42W. The fourth base plate 42 is formed with a first end face M1 around the base recess 421, and bases 226a and 226b are formed at two corners of the base recess 421. A connection electrode 224a electrically connected to the base side electrode 223a (see FIG. 13) is formed on the base 226a on the −X side of the first end face M1 of the fourth base plate 42. Similarly, the connection electrode 424 electrically connected to the connection electrode 224b and the base side surface electrode 223b is formed on the base 226b on the −X side of the first end face M1.

  As described above, the optimal embodiment of the present invention has been described in detail. 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.

  In the first to fourth embodiments, the lid portion and the base portion are joined by the low-melting glass LG, which is a non-conductive adhesive, but a polyimide resin may be used instead of the low-melting glass LG. Good. When a polyimide resin is used, screen printing may be used, or exposure may be performed after a photosensitive polyimide resin is applied to the entire surface. In addition, the mounting terminals are formed at the four corners of the bottom surface of the base portion, but may be a pair of mounting terminals formed on both sides in the X-axis direction. At this time, a mounting terminal for grounding is not formed.

  In each embodiment, a quartz crystal resonator element is used, but a piezoelectric material such as lithium tantalate or lithium niobate can be used in addition to quartz. Furthermore, the present invention can also be applied to a piezoelectric oscillator in which an IC incorporating an oscillation circuit or the like is arranged in a package as a piezoelectric device. In each embodiment, a tuning-fork type crystal vibrating piece having a pair of vibrating arms may be used as the flat AT-cut crystal vibrating piece. Furthermore, in the present invention, a plurality of quartz crystal vibrating pieces are simultaneously formed on one wafer. However, polishing, etching, and electrode formation may be performed on each quartz piece.

DESCRIPTION OF SYMBOLS 10, 20, 30 ... 1st crystal vibrating piece 10W ... Crystal wafer 11 ... Lid board 11W ... Lid wafer 12, 22, 32, 42 ... Base 12W, 22W, 32W, 42W ... Base wafer 13 ... Conductive adhesive 100, 11 , 120, 130... Crystal oscillators 101, 201, 301... Crystal pieces 102a, 102b, 202a, 202b, 302a, 302b... Excitation electrodes 103a, 103b, 203a, 203b, 303a, 303b ... Extraction electrodes 104. Lid concave portion 121,221,321,421 ... Base concave portion 122a, 122b, 222 (a, b, c, d) ... Castellation 123a, 123b, 223a, 223b ... Side electrode 124a, 124b, 224a, 224b, 424 ... Connection Electrode 125, 25a, 125b, 225,225a, 225b ... mounting terminals 226a, 226b, 226c, 226d ... pedestal BH1, BH2 ... through hole CT ... cavity LG ... low-melting glass SL ... scribe line

Claims (7)

A first surface on which a pair of external electrodes are formed; a second surface on which a first recess portion and a first bonding surface around the first recess portion are formed on the opposite side of the first surface; and the first surface A rectangular base having a pair of connection electrodes connected to the external electrodes on the bonding surface;
A rectangular piezoelectric vibrating piece having a pair of excitation electrodes and an extraction electrode extracted from the pair of excitation electrodes, the extraction electrode being fixed to a connection electrode by a conductive adhesive;
A lid that covers the piezoelectric vibrating piece and has a second recess and a second bonding surface around the second recess;
An annular sealing material disposed in an annular shape between the first joint surface and the second joint surface, and sealing the base and the lid;
A piezoelectric device comprising: When the first recess is viewed from the normal direction of the second surface, the first recess is rectangular.
2. The piezoelectric device according to claim 1, wherein the second recess is rectangular when the second recess is viewed from a normal direction of the second surface.   At least two corners of the rectangle of the first dent protrude from the center of the first dent at the same height as the first joint surface, and the pair of connection electrodes are formed at the corner. The piezoelectric device according to claim 2.   4. The piezoelectric device according to claim 3, wherein the two corners are formed on the same short side of the first recess, and the extraction electrode is extracted on the same short side of the piezoelectric vibrating piece.   4. The piezoelectric device according to claim 3, wherein the two corners are respectively formed on short sides facing the first recess, and the extraction electrodes are respectively drawn on short sides facing the piezoelectric vibrating piece.   The said external electrode and the said connection electrode are any one of Claims 1-5 electrically connected via the castellation formed in the side surface which connects the said 1st surface and the said 2nd surface. The piezoelectric device according to item. The piezoelectric device according to any one of claims 1 to 6, wherein the piezoelectric vibrating piece includes a mesa type or a convex type in which a central part is thicker than a peripheral part.