JP2009164775A - Piezoelectric frame and piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric frame (50) having a piezoelectric vibration reed in the shape of a tuning fork, which generates neither level difference nor a groove at a root (321) of a pair of vibration arms (31). <P>SOLUTION: The piezoelectric frame (50) is provided with: having at least a pair of vibration arms (31) extending in the first direction from a base part (39), and having a tunig fork piezoelectric vibration reeds (30) has a first excitation electrode (35) and a second excitation electrode (36) in the pair of vibration arms (31); a first support part (23) extending in the first direction from between the pair of vibration arms (31); an outer frame part (51) connected to the first support part to surround the tuning fork piezoelectric vibration reed; a first connection electrode (33) and a second connection electrode (34) conducted to the first excitation electrode (35) and the second excitation electrode (36), respectively, and formed in the outer frame part (51). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a piezoelectric frame and a piezoelectric device including a tuning fork type piezoelectric vibrator and the like.

  The piezoelectric body has a property of expanding and contracting due to the piezoelectric effect when a voltage is applied, and when this is incorporated into a feedback circuit of a resonance circuit, extremely accurate and stable oscillation is performed. Using this property, the piezoelectric vibrator is used in all electronic products such as time measurement with a watch and generation of a reference signal for an electronic control circuit. Piezoelectric vibrators include a lead type in which lead wires are disposed, and a surface mount type in which a package is mounted on a printed circuit board like a chip capacitor. This surface mount type piezoelectric vibrator is widely used because of its ease of mounting on a printed circuit board, and a tuning fork type piezoelectric vibrator is often used for time measurement and the like.

Patent Document 1 discloses a piezoelectric device including a frame body on these tuning-fork type piezoelectric vibrating reeds. And the piezoelectric device of patent document 1 manufactures the piezoelectric device by joining the lid and base which were made of glass, and the frame. The outer shape of the frame body of the tuning fork type piezoelectric vibrating piece is manufactured from one piezoelectric wafer by applying a photoresist, a photolithography (exposure) technique, and wet etching. Thereafter, an electrode pattern is formed on the tuning-fork type piezoelectric vibrating piece again by applying a photoresist, photolithography (exposure) technique, and wet etching.
JP 2006-229446 A

  However, the piezoelectric wafer has anisotropy, and it is difficult to form the outer shape of the tuning fork type piezoelectric vibrating piece neatly by wet etching. It is difficult to form a pattern.

  For example, FIG. 9 is an explanatory diagram of a conventional tuning-fork type piezoelectric vibrating piece 200. 9A is a plan view showing the overall configuration of the tuning-fork type piezoelectric vibrating piece 200, and FIG. 9B is a plan view of the base 290 when the pair of vibrating arms 210 and the base 290 are viewed in the XZ plane. FIG. 9C is an enlarged view of the pair of vibrating arms 210 and the base portion 290 as seen on the XY plane. In the tuning fork type piezoelectric vibrating piece 200 in recent years, the width of the vibrating arm is about 0.1 mm to 0.2 mm, and the distance between the pair of vibrating arms 210 is also about 0.1 mm to 0.2 mm. The tuning fork type piezoelectric vibrating piece 200 is connected by a connecting portion 281 in order to connect the tuning fork type piezoelectric vibrating piece 200 to a frame (not shown).

  For example, a quartz single crystal wafer is cut out with a predetermined orientation with respect to the crystal axis of a Y-bar Z-plate artificial quartz crystal. This directivity affects the direction in which the crystal single crystal wafer is easily etched and the direction in which it is difficult to etch during wet etching for forming the outer shape of the tuning-fork type piezoelectric vibrating piece 200. For this reason, when the wet etching proceeds from both surfaces of the crystal single crystal wafer at the roots 261 of the pair of vibrating arms 210, a step and a small groove as shown in FIG. 9B or 9C are formed. In this state, if a photoresist is applied to form the electrode pattern of the tuning fork type piezoelectric vibrating piece 200, the photoresist is likely to accumulate in the grooves of the roots 261 of the pair of vibrating arms 21. Moreover, when performing photolithography (exposure) of an electrode pattern, the case where exposure is inadequate easily arises by the influence of a level | step difference. Therefore, when an electrode pattern is formed on the tuning-fork type piezoelectric vibrating piece 200, the electrode pattern is often short-circuited at the roots 261 of the pair of vibrating arms 210. This makes it impossible to improve the productivity and quality of the tuning fork type piezoelectric vibrating piece 200.

  Accordingly, an object of the present invention is to provide a piezoelectric frame and a piezoelectric device having a tuning fork-type piezoelectric vibrating piece that does not cause a step or a groove at the base of a pair of vibrating arms.

A piezoelectric frame according to a first aspect has at least a pair of vibrating arms extending in a first direction from a base, and a tuning fork type piezoelectric vibrating piece having a first excitation electrode and a second excitation electrode on the pair of vibrating arms, A first support portion extending in the first direction from between the pair of vibrating arms, an outer frame portion connected to the first support portion and surrounding the tuning-fork type piezoelectric vibrating piece, and the first excitation electrode and the second excitation electrode, respectively. And a first connection electrode and a second connection electrode formed on the outer frame portion.
According to the above configuration, since the first support portion extending from between the pair of vibrating arms is provided, the first excitation electrode and the second excitation electrode do not short-circuit each other. Further, since the first connection electrode and the second connection electrode are formed on the outer frame portion that is connected to the first support portion and surrounds the tuning fork type piezoelectric vibrating piece, it is suitable for mass production of piezoelectric devices.

The piezoelectric frame according to the second aspect includes a second support portion that extends from the base portion in a second direction opposite to the first direction, and the second support portion is connected to the outer frame portion.
According to the above configuration, since the tuning fork type piezoelectric vibrating piece and the outer frame portion are supported by the second support portion in addition to the first support portion, the strength for supporting the tuning fork type piezoelectric vibrating piece is increased.

According to a third aspect of the piezoelectric frame, in the second aspect, the first excitation electrode is electrically connected to the first connection electrode via the first support portion, and the second excitation electrode is connected to the second connection electrode via the second support portion. Conducted to.
According to the above configuration, the first excitation electrode and the second excitation electrode are electrically connected to the first connection electrode and the second connection electrode through the first support portion and the second support portion, respectively. 2 Even if the support portion has a narrow width, there is little possibility of short-circuiting each other.

A piezoelectric frame according to a fourth aspect includes a first protrusion extending in the first direction from the outer frame toward the base, and a second protrusion extending from the base in a second direction opposite to the first direction. .
According to the above configuration, the first excitation electrode and the second excitation electrode formed on the side surface of the tuning fork type piezoelectric vibrating piece or the outer frame portion can be removed by the first protrusion or the second protrusion, and short-circuit each other. The fear can be reduced.

In a fourth aspect of the piezoelectric frame of the fifth aspect, the first excitation electrode and the second excitation electrode are electrically connected to the first connection electrode and the second connection electrode through the first support portion.
According to the above configuration, the tuning fork-type piezoelectric vibrating piece can be supported on the outer frame portion with one first support portion and can be electrically connected.

A piezoelectric device according to a sixth aspect includes a piezoelectric frame according to any one of the first to fifth aspects, a lid that covers the piezoelectric frame, a first connection terminal that supports the piezoelectric frame and is electrically connected to the first connection electrode. And a base having a second connection terminal conducting to the second connection electrode.
According to the above configuration, since the piezoelectric device uses the piezoelectric frame having the first support portion extending from between the pair of vibrating arms, there is no possibility that the first excitation electrode and the second excitation electrode are short-circuited.

In the piezoelectric device of the seventh aspect, the material of the lid part and the material of the base are glass containing metal ions, and the outer frame part of the piezoelectric frame has a metal film formed around it, and the metal film of the outer frame part The lid and the base are anodically bonded.
It is possible to provide a piezoelectric device in which the lid portion and the base portion are made of glass and are easily mass-produced.

In the piezoelectric device according to the eighth aspect, the material of the lid and the material of the base are piezoelectric materials, and the piezoelectric frame, the lid, and the base are siloxane-bonded.
According to the said structure, the cover part and a base part are comprised with a piezoelectric material, and can provide the piezoelectric device which is easy to mass-produce.

According to the present invention, it is possible to form a piezoelectric frame having a tuning-fork type piezoelectric vibrating piece in which the electrode pattern is not short-circuited at the base between the first vibrating arm and the second vibrating arm.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Configuration of tuning fork type crystal vibrating piece 30>
FIG. 1A is a plan view showing an overall configuration of a crystal frame 50 including the tuning fork type crystal vibrating piece 30 of the first embodiment, and FIG. 1B is a plan view of one tuning fork type crystal vibrating piece 30. 4 is a cross-sectional view of the vibrating arm 31 taken along the line BB.

  The crystal frame 50 has a so-called tuning fork type crystal vibrating piece 30 at the center thereof and an outer frame portion 51 on the outside, and a space 52 is formed between the tuning fork type crystal vibrating piece 30 and the outer frame portion 51. Has been. The space portion 52 that defines the outer shape of the crystal vibrating piece 30 is formed by crystal etching. The tuning fork type crystal vibrating piece 30 includes a base portion 39 and a pair of vibrating arms 31 extending from the base portion 39. The base portion 39 and the outer frame portion 51 are integrally formed, and the first connection electrode 33 and the second connection electrode 34 are formed on the first main surface of the outer frame 51.

  The quartz crystal vibrating piece 30 has a first excitation electrode 35 and a second excitation electrode 36 formed on a first main surface and a second main surface, and the first excitation electrode 35 is a first electrode formed on an outer frame portion 51. The second excitation electrode 36 is connected to the connection electrode 33, and the second excitation electrode 36 is connected to the second connection electrode 34 formed in the outer frame portion 51. Further, a weight portion 37 and a weight portion 38 are formed at the tip of the vibrating arm 31 of the crystal vibrating piece 30. The first connection electrode 33 and the second connection electrode 34, the first excitation electrode 35 and the second excitation electrode 36, the weight part 37 and the weight part 38 are simultaneously formed by a photolithography process. When a voltage is applied to these, the crystal vibrating piece 30 vibrates at a predetermined frequency. The weight part 37 and the weight part 38 are weights for the crystal vibrating piece 30 vibrating arm 31 to vibrate easily and are provided for frequency adjustment.

  The base material of the crystal frame 50 provided with the tuning fork type crystal vibrating piece 30 is formed of a crystal single crystal wafer 10 processed into a Z plate. In order to obtain the required performance in a small size, as shown in FIG. 1A, the tuning fork type crystal vibrating piece 30 includes a first support portion 23 extending from the base portion 39 toward the upper side of FIG. A pair of vibrating arms 31 extending in parallel from the one end portion of the support portion 23 is provided. The first support portion 23 extends in the same direction as the vibrating arm 31 from the center portion of the pair of vibrating arms 31 and is connected to the outer frame portion 51 on the facing side of the base portion 39. The roots 321 of the pair of vibrating arms 31 are provided with a tapered portion to suppress fluctuations and variations in the resonance frequency due to changes in the ambient temperature. The shape of the tapered portion of the root 321 may be U-shaped.

  Moreover, the 2nd support part 26 extended toward the downward direction of FIG. 1 from the base 39 is provided. The second support portion 26 supports the tuning fork type crystal vibrating piece 30 from the outer frame portion 51 together with the first support portion 23.

  The tuning fork type crystal vibrating piece 30 is a vibrating piece that transmits a signal at, for example, 32.768 kHz, and is an extremely small vibrating piece. The entire length is about 1.7 mm and the width is about 0.5 mm. Grooves 31 a are formed on both front and back surfaces of the vibrating arm 31 of the tuning fork type crystal vibrating piece 30. Two groove portions 31 a are formed on the surface of one vibrating arm 31, and two groove portions 31 a are similarly formed on the back surface side of the vibrating arm 31. That is, four groove portions 31 a are formed in the pair of vibrating arms 31. The depth of the groove portion 31a is about 35 to 45% of the thickness of the crystal single crystal wafer 10, and the groove portions 31a are present on both the front and back surfaces. Therefore, as shown in FIG. It is formed in an H shape. The groove 31a is provided to suppress an increase in CI value.

  The vibrating arm 31 and the outer frame portion 51 of the tuning-fork type crystal vibrating piece 30 include a first connection electrode 33 and a second connection electrode 34, a first excitation electrode 35 and a second excitation electrode 36, a weight portion 37 and a weight portion 38. Is formed. As shown in FIG. 1B, second excitation electrodes 36 are formed on both side surfaces of the left arm portion 31 in FIG. A first excitation electrode 35 is formed in the groove 31a. These electrodes have a structure in which a gold (Au) layer of 100 angstroms to 5000 angstroms is formed on a chromium (Cr) layer of 150 angstroms to 5000 angstroms. That is, when the first layer and the second layer are combined, the thickness of the electrode pattern is 250 Å to 10000 Å. Further, a tungsten (W) layer, a nickel (Ni) layer, a nickel tungsten layer, or a titanium (Ti) layer may be used instead of the chromium (Cr) layer, and silver instead of the gold (Au) layer. An (Ag) layer may be used. In some cases, an aluminum (Al) layer, a copper (Cu) layer, or a silicon (Si) layer is used.

  There is a possibility that the photoresist remains in the groove of the root 321 of the vibrating arm 31 when the photoresist is applied, and that the exposure may be insufficient due to the step difference when the photolithography (exposure) of the electrode pattern is performed. There is. In such a case, the presence of the first support portion 23 extending upward from the base 321 of the pair of vibrating arms 31 allows the remaining metal film to be connected to the pair of vibrating arms 31 due to non-photosensitivity. There is no. Therefore, even if an electrode pattern is formed on the tuning fork type crystal vibrating piece 30, the electrode pattern does not short-circuit at the roots 321 of the pair of vibrating arms 31. Further, the second support portion 26 prevents the first excitation electrode 35 and the second excitation electrode 36 on the side surface of the tuning fork type crystal vibrating piece 30 from short-circuiting.

  The first excitation electrode 35 is connected to the first connection electrode 33 through the first support portion 23, and the second excitation electrode 36 is connected to the second connection electrode 34 through the second support portion 26. Even if the first support portion 23 and the second support portion 26 are thin, the first excitation electrode 35 and the second excitation electrode 36 extend to the first support portion 23 and the second support portion 26 that extend in different directions, respectively. There is no danger of short-circuiting each other.

  FIG. 2 is a plan view showing the overall configuration of a crystal frame 50 ′ including a tuning fork type crystal vibrating piece 30 ′ according to the second embodiment. The functions described in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted. The crystal frame 50 ′ has a so-called tuning-fork type crystal vibrating piece 30 ′ at the center and an outer frame 51 on the outside, and a pair of vibrating arms 31 extends upward from FIG. 2 from both ends of the base 39. Is formed. A space 52 is provided between the base 39 and the outer frame 51. A space 52 is formed between the tuning-fork type crystal vibrating piece 30 ′ and the outer frame 51. The space 52 that defines the outer shape of the quartz crystal vibrating piece 30 ′ is formed by crystal etching. The tuning fork type crystal vibrating piece 30 ′ is supported by a first support portion 23 extending from the base portion 39 toward the outer frame portion 51, and unlike the tuning fork type crystal vibrating piece 30 ′ of the first embodiment, the second support portion 26 is provided. I don't have it.

  As described in the first embodiment, the presence of the first support portion 23 prevents the metal film remaining due to non-photosensitivity from connecting the pair of vibrating arms 31. Therefore, even if an electrode pattern is formed on the tuning fork type crystal vibrating piece 30, the electrode pattern does not short-circuit at the roots 321 of the pair of vibrating arms 31. In addition, one or a plurality of protrusions 25 are formed on the side surface 301 of the inverted T base 39. One or a plurality of projections 25 are also formed on the side surface 511 of the outer frame portion 51 on the base 39 side.

  The side surface 301 of the tuning-fork type crystal vibrating piece 30 ′ and the side surface 511 of the outer frame portion 51 are not easily exposed to light and a photoresist residue is likely to remain. For this reason, the metal film continues on the side surface 301 or the side surface 511, resulting in a short circuit failure. Providing the protrusions 25 on the side surface 301 and the side surface 511 makes it easy to expose the protrusions, the photoresist is exposed, and the photoresist can be removed and the metal film can be removed.

  The first excitation electrode 35 and the second excitation electrode 36 are connected to the first connection electrode 33 and the second connection electrode 34 through the first support portion 23. Since the first excitation electrode 35 and the second excitation electrode 36 pass through the first support portion 23, the width of the first support portion 23 is preferably wider than that of the first embodiment in the second embodiment. From the viewpoint of supporting the weight of the tuning-fork type crystal vibrating piece 30 ′ with the first support portion 23, the first support portion 23 is preferably wider.

<Configuration of First Crystal Resonator 100>
Hereinafter, the first crystal unit 100 according to the embodiment will be described with reference to the drawings. FIG. 3A shows a schematic diagram of the first crystal unit 100.
FIG. 3A (a) is an overall cross-sectional view taken along the line AA in FIG. 3C showing the configuration of the first crystal unit 100, FIG. 3B is an inner surface view of the first lid 20, and FIG. FIG. 4 is a top view of the crystal frame 50, and (d) is a top view of the first base 40.

  In FIG. 3A (a), the first crystal resonator 100 is formed by bonding a first base 40 under the crystal frame 50 around the crystal frame 50 including the tuning fork type crystal vibrating piece 30. The first lid 20 is joined to the top. The first lid 20 and the first base 40 are made of glass, and the first lid 20 has a lid recess 27 on one surface on the crystal frame 50 side. The first base 40 has a base recess 47 on one side of the crystal frame 50 side. The crystal frame 50 has a tuning fork type crystal vibrating piece 30 formed from the crystal wafer 10 and formed by etching.

As shown in FIG. 3A (b), the first lid 20 includes a lid recess 27 formed by etching.
As shown in FIG. 3A (c), the crystal frame 50 has a so-called tuning fork type crystal vibrating piece 30 at the center thereof and an outer frame portion 51 on the outside, and the tuning fork type crystal vibrating piece 30 and the outer frame portion 51 are provided. A space 52 is formed between the two. The space 52 that defines the outer shape of the tuning fork type crystal vibrating piece 30 is formed by crystal etching. The tuning fork type crystal vibrating piece 30 is as described in the first embodiment.

  A metal film 53 is provided on the front and back surfaces of the outer frame portion 51. The metal film 53 is formed by a technique such as sputtering or vacuum deposition. The metal film 53 is formed of an aluminum (Al) layer, and the thickness of the aluminum layer is about 1000 to 1500 mm. The metal film 53 may be a metal film in which a gold layer is stacked on a base chromium layer, in addition to aluminum.

  The first base 40 shown in FIG. 3D is made of glass. When the base recess 47 is provided by etching, the first through hole 41 and the second through hole 43 are simultaneously formed, and the stepped portion 49 is formed. . A first connection terminal 42 and a second connection terminal 44 are provided on the surface of the first base 40. The first connection terminal 42 and the second connection terminal 44 are formed in a stepped portion 49.

The first through hole 41 and the second through hole 43 are formed with a metal film on the inner surface, and the metal film on the inner surface is formed at the same time as the first connection terminal 42 and the second connection terminal 44 by a photolithography process. A gold (Au) layer or a silver (Ag) layer is formed on the inner metal film. The first base 40 includes a first external electrode 45 and a second external electrode 46 that are metallized on the bottom surface. The first connection terminal 42 is connected to the first external electrode 45 provided on the bottom surface of the first base 40 through the first through hole 41. The second connection terminal 44 is connected to the second external electrode 46 provided on the bottom surface of the first base 40 through the second through hole 43.
The first connection electrode 33 and the second connection electrode 34 formed on the second main surface of the outer frame portion 51 are connected to the first connection terminal 42 and the second connection terminal 44 on the surface of the first base 40, respectively.

  FIG. 3B shows a schematic cross-sectional view of performing anodic bonding for package bonding. The first lid 20 and the first base 40 are made of Pyrex (registered trademark) glass, borosilicate glass, soda glass, or the like, and these are glasses containing metal ions such as sodium ions. The first lid 20 having the lid concave portion 27 and the first base 40 having the base concave portion 47 are overlapped with each other around the crystal frame 50 having the tuning fork type crystal vibrating piece 30.

  Then, pressurizing while heating from 200 ° C. to 400 ° C. in a vacuum or in an inert gas, the upper surface of the first lid 20 is set to a negative potential, and the metal films 53 on the front and back surfaces of the outer frame portion 51 are added. The package 80 is formed by applying a DC voltage of 400 V for 10 minutes using a DC power supply 90 and bonding them by an anodic bonding technique.

  By the way, anodic bonding is established by a chemical reaction in which a metal at the bonding interface is oxidized. For example, in anodic bonding between the crystal frame 50 and the first lid 20 and the first base 40, a metal film 53 such as aluminum is formed on the bonding surface of the crystal frame 50 by sputtering or the like, and a glass member is formed on the surface of the formed metal film. Anodic bonding is performed by bringing the bonding surfaces into contact with each other.

  When anodic bonding is performed, a metal film is used as an anode, a cathode is disposed on a surface facing the bonding surface of the glass member, and an electric field is applied therebetween. As a result, metal ions such as sodium contained in the glass move to the cathode side, and as a result, the metal film in contact with the glass member at the bonding interface is oxidized, and a state where both are connected is obtained. In this embodiment, when a predetermined metal such as aluminum and a predetermined dielectric are brought into contact with each other and heated (about 200 ° C. to 400 ° C.) and a voltage of about 500 V to 1 kV is applied, the metal and the glass are interfaced. This is a joining method using the property of chemically bonding.

<Configuration of Second Crystal Resonator 110>
Hereinafter, the second crystal unit 110 will be described with reference to the drawings. FIG. 4 shows a schematic diagram of the second crystal unit 110 of the present invention.
FIG. 4A is an overall cross-sectional view of “A-A” in FIG. 4B showing the configuration of the second crystal unit 110, and this overall cross-sectional view is a cross-section of each member before joining to help understanding. The figure is shown. FIG. 4B is a top view of the crystal frame 50, and FIG. 4C is a top view of the second base 40 ′.

  In FIG. 4A, the second crystal unit 110 includes an upper second lid 20 ′, a lower second base 40 ′, and a central crystal frame 50. The crystal frame 50 is as described in the first embodiment. The second lid 20 ', the second base 40' and the quartz material are formed. The second lid 20 'has a lid recess 27' formed by etching on one side of the crystal frame 50 side. The second base 40 ′ has a base recess 47 ′ formed by etching on one side of the crystal frame 50 side.

  In the second crystal unit 110, a second base 40 ′ is joined below the crystal frame 50 around the crystal frame 50 including the tuning fork type crystal vibrating piece 30, and the second lid 20 is mounted on the crystal frame 50. 'Is joined. That is, the second lid 20 ′ is configured to be bonded to the crystal frame 50 and the second base 40 ′ is bonded to the crystal frame 50 by a siloxane bonding (Si—O—Si) technique. Since the crystal frame 50 is bonded by a siloxane bonding technique, a metal film for bonding is not necessary.

  As shown in FIG. 4B, the crystal frame 50 has a tuning fork type crystal vibrating piece 30 at the center and an outer frame portion 51 on the outside, and the tuning fork type crystal vibrating piece 30 and the outer frame portion 51. A space 52 is formed between the two. In the crystal frame 50, the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 4C, when the second base 40 ′ is provided with the base recess 47 ′ by etching, the first through hole 41 ′ and the second through hole 43 ′ are formed at the same time, and the step portion 49 is formed. 'Is formed. The second base 40 'includes a first connection terminal 42' and a second connection terminal 44 '. The first connection terminal 42 ′ and the second connection terminal 44 ′ are formed in the step portion 49 ′.

  The first through hole 41 ′ and the second through hole 43 ′ have a metal film formed on the inner surface thereof, and the metal film on the inner surface is formed by a photolithography process simultaneously with the first connection terminal 42 ′ and the second connection terminal 44 ′. Created. The metal film on the inner surface has a nickel or chromium layer formed on the base, and a gold (Au) layer or silver (Ag) layer formed thereon. The base 40 'includes a first external electrode 45' and a second external electrode 46 'that are metalized on the bottom surface. The first connection terminal 42 ′ is connected to the first external electrode 45 ′ provided on the bottom surface of the base 40 ′ through the first through hole 41 ′. The second connection terminal 44 ′ is connected to the second external electrode 46 ′ provided on the bottom surface of the base 40 ′ through the second through hole 43 ′.

  The second lid 20 ′, the second base 40 ′, and the crystal frame 50 as described above are bonded by a siloxane bond. The siloxane bond is centered on the crystal frame 50 including the crystal vibrating piece 30 and the contact surface of the second base 40 ′ provided with the base recess 47 ′ and the second lid 20 ′ provided with the lid recess 27 ′. In a clean state, they are superposed and heated by applying pressure in a high-temperature bath maintained at 400 ° C. to 450 ° C., thereby completing the coupling and piezo-electric vibrator packaging.

  If the bottom surface of the crystal frame 50 and the top surface of the base 40 ′ are to be joined without the stepped portion 49 ′, the total of the base electrode formed on the crystal frame 50 and the connection electrode formed on the base 40 ′. The thickness is 3000 to 4000 mm, and the bottom surface of the crystal frame 50 and the top surface of the base 40 ′ are often not coupled. On the other hand, if the stepped portion 49 ′ having a depth equivalent to the total thickness (from 3000 mm to 4000 mm) of the base electrode and the connection electrode is provided, the crystal frame 50 and the crystal base 40 ′ can be siloxane-bonded. Since the first connection electrode 33 and the second connection electrode 34 may not be coupled to the first connection terminal 42 ′ and the second connection terminal 44 ′, both may not be conductive. A stepped portion 49 ′ is provided.

<Sealing process>
FIG. 5A shows a partially enlarged sectional view in which the first crystal unit 100 of the first embodiment is installed upside down. After the packaging is completed, the first through hole 41 and the second through hole 43 of the first base 40 are sealed.
The sealing material 60 is filled with one of a eutectic alloy such as a gold silicon (Au 3.15 Si) alloy, a gold germanium (Au 12 Ge) alloy, or a gold tin (Au 20 Sn) alloy, and is heated at a high temperature in a vacuum or in an inert gas. Hold in a bath and seal. The melting point of the gold silicon alloy is 363 ° C., the melting point of the gold germanium alloy is 356 ° C., and the melting point of the gold tin (Au20Sn) alloy is 280 ° C.

  When a gold silicon alloy or a gold germanium alloy is used as the sealing material 60, the temperature of the high-temperature tank is set to about 380 to 420 ° C. When using a gold-tin alloy as the sealing material 60, the temperature of the high-temperature tank is about 300 to 320 ° C. Thereby, the crystal unit 100 in which the inside of the package 80 is evacuated or filled with the inert gas is completed. Alternatively, the sealing material 60 may be obtained by heating and melting and dropping a silver solder wire or a gold solder wire into the first through hole 41 and the second through hole 43 with a burner or the like. The melting temperature of the silver solder wire or the gold solder wire is about 600 ° C. or higher or 800 ° C. or higher.

  Even if the temperature in the reflow furnace for soldering crystal devices and other surface mount devices with solder paste in the circuit board mounting process may be 260 ° C or higher, the sealing material 60 may melt and impair airtightness. Does not happen.

  FIG. 5B shows a partially enlarged sectional view in which the second crystal unit 110 is installed upside down. After the siloxane bonding of the second lid 20 ′, the crystal frame 50, and the lowermost second base 40 ′, the first through hole 41 ′ and the second through hole 43 ′ of the second base 40 ′ are used as the sealing material 60. One of a gold silicon (Au 3.15Si) alloy, a gold germanium (Au12Ge) alloy, or a gold tin (Au20Sn) alloy is filled. And it seals in the high temperature tank in the vacuum of the temperature around 400 degreeC, or in inert gas. Thereby, the second crystal unit 110 in which the inside of the package 80 is evacuated or filled with the inert gas is completed. A silver solder wire or a gold solder wire may be heated and melted and dropped with a burner or the like to be sealed.

  In FIG. 5B, the step of performing the sealing step after the siloxane bonding of the second lid 20 ′, the crystal frame 50, and the lowermost second base 40 ′ has been described, but gold silicon (Au 3.15 Si) is described. When an alloy or a gold germanium (Au12Ge) alloy is used as the sealing material 60, bonding and sealing can be performed simultaneously when siloxane bonding is performed.

<Manufacturing Process of Crystal Frame 50 and Tuning Fork Type Crystal Vibrating Piece 30>
FIG. 6A is a schematic perspective view showing the crystal wafer 10 on which the crystal frame 50 is formed. The state shown in FIG. 6A is a view showing a state in which a crystal frame 50 having a tuning fork type crystal vibrating piece 30 is formed by etching from a circular crystal wafer 10. The crystal region 50 having the tuning-fork type crystal vibrating piece 30 is formed by etching the opening region 12 and the space portion 52 indicated by hatching from the circular crystal wafer 10. A plurality of crystal frames 50 having the tuning fork type crystal vibrating piece 30 are formed, for example, as one block of three. An orientation flat 10c for specifying the crystal direction of the crystal is formed in a part of the peripheral portion 10e of the crystal wafer 10. For convenience of explanation, 33 tuning-fork type crystal vibrating pieces 30 are drawn on the quartz wafer 10, but in reality, hundreds or thousands of tuning-fork type crystal vibrating pieces 30 are formed on the quartz wafer 10.

  In FIG. 6A, the crystal frame 50 is not separated from the crystal wafer 10, and a part of the crystal frame 50 is connected to the circular crystal wafer 10 by the connecting portion 11. For this reason, it is possible to handle one crystal wafer 10 unit without processing each crystal frame 50.

FIG. 6B is an enlarged plan view of one block of the tuning fork type crystal vibrating piece 30 and the crystal frame 50. The crystal frame 50 is formed in a predetermined size by etching the hatched opening region 12 from the circular crystal wafer 10. A connecting portion 11 is formed on a part of the outer periphery of the crystal frame 50. The connecting portion 11 connects the circular crystal wafer 10 and the crystal frame 50 so that a plurality of crystal frames 50 can be simultaneously handled in units of the circular crystal wafer 10. A space portion 52 (shaded portion) that defines the outer shape of the crystal vibrating piece 30 is formed by etching simultaneously with the opening region 12.
Further, the first and second connection electrodes 33 and 34, the first excitation electrode 35 and the second excitation electrode 36, and the weight portion 37 and the weight portion 38 are formed on the crystal vibrating piece 30 in units of the quartz wafer 10.

<Manufacturing Process of Crystal Resonator 110 of Second Embodiment>
FIG. 7 shows a crystal wafer 10 on which a second lid 20 ′ is formed, a crystal wafer 10 on which a tuning fork type crystal vibrating piece 30 and a crystal frame 50 are formed, and a crystal wafer 10 on which a second base 40 ′ is formed. FIG. The second lid 20 ′ and the second base 40 ′ are both connected to the crystal wafer 10 by the connecting portion 11.

  At the time of superposition, the lid recess 27 ′ of the second lid 20 ′ has already been formed by crystal etching. In addition, a lid recess 47 'of the second base 40' is formed by crystal etching, and further, a first connection terminal 42 'and a second connection terminal 44' are also formed. As described with reference to FIGS. 6A and 6B, the tuning fork type crystal vibrating piece 30 is formed with the first connection electrode 33, the second connection electrode 34, the first excitation electrode 35, and the second excitation electrode 36.

  Since each quartz wafer 10 has a diameter of, for example, 4 inches and an orientation flat 10c is formed, the three quartz wafers 10 are accurately aligned and overlapped. The three quartz wafers 10 that are superposed are siloxane bonded. As described with reference to FIG. 4, when the quartz wafers 10 are bonded to each other by siloxane, the first connection electrode 33 and the second connection electrode 34 are also firmly bonded to the first connection terminal 42 ′ and the second connection terminal 44 ′.

  In the state where the three quartz wafers 10 are superposed, the common coupling portion 11 is folded to complete the quartz crystal resonator 110. So-called packaging and electrode bonding can be performed at the same time, and since it can be manufactured in units of quartz wafers, productivity can be improved. Further, as described in FIG. 5B, the first through hole 41 ′ and the second through hole 43 ′ of the second base 40 ′ are filled with a gold silicon alloy or a gold germanium alloy, and are in a vacuum or inactive. By holding it in a high-temperature bath in gas, it is possible to simultaneously bond the package by siloxane bond and seal the package. This further reduces man-hours and can reduce costs.

Since the second crystal unit 110 is completed in units of crystal wafers, the second crystal unit 110 is completed as a product by cutting out one by one by dicing.
Although the first crystal unit 100 of the first embodiment is not described in detail, the first crystal unit 100 can also be manufactured in units of crystal wafers and glass wafers.

<Flowchart showing Manufacturing Method of First Crystal Resonator 100 and Second Crystal Resonator 110>
8A to 8B are flowcharts showing a manufacturing method according to the first crystal unit 100 and the second crystal unit 110 of the present invention. 8A and 8B, the first through hole 41 and the second through hole 43 of the first crystal unit 100 are sealed with a gold silicon alloy or a gold germanium alloy. The case where the first through hole 41 ′ and the second through hole 43 ′ of the crystal unit 110 are sealed with a gold silicon alloy or a gold germanium alloy is described.

FIG. 8A is a flowchart showing a pattern for creating a part from various materials.
Step P1 shows the material used in this embodiment. The material used consists of a quartz wafer and glass. Since the detailed explanation has already been made, only the main points will be explained.
Step P2 shows the name of a part created from the material. A second lid 20 ′, a second base 40 ′, and a crystal frame 50 are formed from the crystal wafer. The first lid 20 and the first base 40 are formed from glass such as Pyrex (registered trademark) glass, borosilicate glass, and soda glass. The crystal frame 50 is used for both the first crystal unit 100 and the second crystal unit 110. When used in the first crystal unit 100, a bonding metal film 53 is formed on the outer frame portion 51 of the crystal frame 50 in step P4.

  In step P3, the contents of work performed in the etching process for creating each member are shown. A first lid recess 27 is formed in the first lid 20 and a second lid recess 27 ′ is formed in the second lid 20 ′ by etching. The first base recess 47, the through holes 41 and 43, and the steps are formed in the first base 40. A portion 49 is formed. A second base recess 47 ′ is formed in the second base 40 ′, and a second base recess 47 ′, through holes 41 ′ and 43 ′, and a step portion 49 ′ are formed in the second base 40 ′.

  Step P4 shows the work contents for forming each electrode part by vacuum deposition or sputtering in the photolithography process. A metal film is formed on the inner surfaces of the through holes 41 and 43 of the first base 40 by a photolithography process. External electrodes 45 and 46 are formed on the bottom surface of the first base 40 by metalizing. A metal film is formed on the inner surfaces of the through holes 41 ′ and 43 ′ of the second base 40 ′ by a photolithography process. An external electrode 45 ′ and an external electrode 46 ′ are formed on the bottom surface of the second base 40 ′ by metalizing.

  In the crystal vibrating piece 30, the first connection electrode 33 and the second connection electrode 34, the first excitation electrode 35 and the second excitation electrode 36, the weight portion 37 and the weight portion 38 are simultaneously formed by a photolithography process. In the crystal frame 50 used in the first embodiment, a metal film 53 for bonding is formed on the outer frame portion 51 by sputtering.

  In Step P5, cleaning and cleaning operations for the bonding surfaces of the second lid 20 ', the second base 40', and the crystal frame 50 are shown. When the purification work is insufficient, the siloxane bonding temperature becomes high and 500 ° C. or more is required. Typical siloxane bonding temperature is 350 ° C to 450 ° C.

FIG. 8B is a flowchart showing a packaging and through hole sealing pattern.
In step P6 (a), packaging and through-hole sealing are performed simultaneously in step P7, so there is no corresponding work. In (b), the second base 40 ′ and the second lid 20 ′ are stacked with the quartz frame 50 as the center, and pressure is applied while heating in a chamber of 400 ° C. to 450 ° C. to perform siloxane bonding, whereby the package 80 ′. Is formed.

  In Step P6 (c), the first base 40 and the first lid 20 are overlapped around the quartz frame 50 provided with the Al metal film 53, and are pressurized while being heated in a chamber of 250 ° C to 400 ° C. By performing anodic bonding, the package 80 is formed.

  Step P7 (a) shows a step of sealing the through hole simultaneously with the bonding of the package 80 '. First, the contact surfaces of the second base 40 ′ and the second lid 20 ′ are superposed on a quartz frame in the high temperature bath in vacuum or in an inert gas, and then the second lid 20 is turned upside down. Set 'to be at the bottom. By filling the through holes 41 ′ and 43 ′ of the second base 40 ′ with the sealing material 60 and applying pressure while heating to 400 ° C., siloxane bonding is performed, and the sealing material 60 is melted and sealed simultaneously with the joining. Stop. As a result, the second crystal unit 110 in which the inside of the package 80 'is evacuated or filled with the inert gas is completed in Step P8.

  In Step P7 (b), the package 80 ′ formed of siloxane bonds is installed upside down, and the sealing material 60 is filled into the through holes 41 ′ and 43 ′ of the second base 40 ′, and the temperature is set to 400 ° C. By applying pressure while heating, the sealing material 60 is melted and sealed. Thereby, the first crystal unit 110 in which the inside of the package 80 ′ is evacuated or filled with the inert gas is completed in Step P <b> 8.

  In step P7 (c), the package 80 formed by anodic bonding in step P6 (c) is melted in the same process as in step P7 (b), and the inside of the package is evacuated or inert gas. The first crystal unit 100 filled with is completed.

  The preferred embodiments of the present invention have been described in detail above. 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. it can. For example, the quartz crystal resonator element 10 of the present invention can use various piezoelectric single crystal materials such as lithium niobate in addition to quartz.

(A) is the top view which showed the whole structure of the crystal frame 50 provided with the tuning fork type crystal vibrating piece 30 of 1st Embodiment. FIG. 4B is a cross-sectional view of the vibrating arm 31 of the tuning-fork type crystal vibrating piece 30 taken along the line BB. It is the top view which showed the whole structure of crystal frame 50 'provided with the tuning fork type crystal vibrating piece 30' of 2nd Embodiment. FIG. 4A is an overall cross-sectional view taken along line AA of FIG. FIG. 6B is an inner surface view of the first lid 20. FIG. 3C is a top view of the crystal frame 50. FIG. FIG. 4D is a top view of the first base 40. The schematic sectional drawing which performs anodic bonding for package bonding is shown. (A) is a schematic sectional view of the second crystal unit 110. FIG. 4B is a top view of the crystal frame 50. FIG. (D) is a top view of the base 40 ′. FIG. 4A is a partially enlarged cross-sectional view of sealing a through hole of the first crystal resonator 100 with a sealing material. FIG. 5B is a partially enlarged cross-sectional view of sealing the through hole of the second crystal resonator 110 with a sealing material. 1 is a schematic perspective view showing a quartz wafer 10 on which a quartz frame 50 including a tuning fork type quartz vibrating piece 30 is formed. 2 is an enlarged schematic plan view of a part of a crystal frame 50 in the crystal wafer 10. FIG. FIG. 6 is a perspective view in which the crystal wafer 10 of the second lid 20 ′, the crystal wafer 10 of the tuning fork type crystal vibrating piece 30 and the crystal frame 50, and the crystal wafer 10 of the second base 40 ′ are overlaid. It is a flowchart which shows the pattern which produces the components of a crystal oscillator. It is a flowchart which shows the packaging and sealing pattern of a crystal oscillator. FIG. 2A is a plan view showing the overall configuration of a tuning fork type crystal vibrating piece 200. FIG. FIG. 5B is an enlarged view of the base 290 when the pair of vibrating arms 210 and the base 290 are viewed in the XZ plane. (C) is the figure which looked at a pair of vibrating arm 210 and the base 290 in XY plane.

Explanation of symbols

10 ...... Quartz wafer 11 ...... Connecting portion 12 ...... Opening 20, 20 ′ …… Lid (first lid, second lid)
23, 26 ... 1st support part, 2nd support part 25 ... Projection part 27, 27 '... Lid recessed part 30, 200 ... Tuning fork type crystal vibrating piece 31, 210 ... Vibration arm 31a ... Groove part 33, 34 ... First base electrode, second base electrode 35, 36 ... First excitation electrode, second excitation electrode 37, 38 ... Weight part 39, 290 ... Base part 40, 40 '... Base (first base) , 2nd base)
41, 43 ... Through holes 42, 42 ', 44, 44' ... Connection terminals 45, 45 ', 46, 46' ... External electrodes 47, 47 '... Base recesses 49, 49' ... Steps 50 ...... Quartz frame 51 ...... Outer frame portion 52 ...... Opening 53 ...... Metal film 60 ...... Sealing material 80, 80 ′ ...... Package 90 …… DC power supply 100, 110 ...... First crystal resonator, Second crystal unit 301... Side surface 261 of crystal vibrating piece ...... Base 281 of vibration arm 210 ...... Connection portion 321 ...... Base 511 of vibration arm 31 ...... Side surface of outer frame portion 51

Claims (8)

A tuning fork-type piezoelectric vibrating piece having at least a pair of vibrating arms extending in the first direction from the base, and having a first excitation electrode and a second excitation electrode on the pair of vibrating arms;
A first support portion extending in a first direction from between the pair of vibrating arms;
An outer frame portion connected to the first support portion and surrounding the tuning-fork type piezoelectric vibrating piece;
A first connection electrode and a second connection electrode which are respectively connected to the first excitation electrode and the second excitation electrode and formed on the outer frame portion;
A piezoelectric frame comprising: A second support portion extending from the base portion in a second direction opposite to the first direction;
The piezoelectric frame according to claim 1, wherein the second support portion is connected to the outer frame portion.   The first excitation electrode is electrically connected to the first connection electrode via the first support part, and the second excitation electrode is electrically connected to the second connection electrode via the second support part. The piezoelectric frame according to claim 2. A first protrusion extending in the first direction from the outer frame toward the base;
The piezoelectric frame according to claim 1, further comprising a second protrusion extending from the base in a second direction opposite to the first direction.   5. The piezoelectric frame according to claim 4, wherein the first excitation electrode and the second excitation electrode are electrically connected to the first connection electrode and the second connection electrode through the first support portion. The piezoelectric frame according to any one of claims 1 to 5,
A lid that covers this piezoelectric frame;
A base that supports the piezoelectric frame and has a first connection terminal that is electrically connected to the first connection electrode and a second connection terminal that is electrically connected to the second connection electrode;
A piezoelectric device comprising: The material of the lid and the material of the base are glass containing metal ions,
A metal film is formed around the outer frame portion of the piezoelectric frame,
The piezoelectric device according to claim 6, wherein the metal film of the outer frame portion, the lid portion, and the base are anodically bonded. The material of the lid and the material of the base are piezoelectric materials,
The piezoelectric device according to claim 6, wherein the piezoelectric frame, the lid, and the base are siloxane-bonded.