JP2018006901A - Crystal diaphragm, and crystal vibration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal diaphragm having a wiring structure of a higher-reliability extraction electrode in which disconnection is unlikely to occur, and a crystal vibration device at lower cost.SOLUTION: A crystal vibration device comprises: an AT cut crystal diaphragm 2 having a tabular shape and including a thin vibration part 23 that is formed in the center, a thick outer frame part 24 that is formed in a circumference of the vibration part and step walls 25 and 26 which connect the surroundings of the vibration part with the outer frame part; a pair of excitation electrodes 201 and 202 formed on both principal surfaces of the vibration part of the crystal diaphragm; and at least a pair of extraction electrodes 203 and 204 connected with the excitation electrodes and extending from the vibration part to a portion of the outer frame part. In the step walls of the crystal diaphragm, uneven surface step wall parts 2591, 2592, 2691 and 2692 are formed in portions where the extraction electrodes pass.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crystal resonator device such as a crystal resonator and a crystal filter.

  At present, the oscillation frequency of a crystal resonator or a crystal filter using a thickness-shear vibration type crystal vibration plate such as an AT-cut crystal vibration plate is being increased. The quartz diaphragm used in this quartz-crystal vibrating device has an inverted mesa structure in which the vibrating part is thinly molded in order to cope with the increase in the oscillation frequency, and thin-film excitation electrodes are formed on both main surfaces of the thin-walled vibrating part. (For example, refer to Patent Document 1).

  In the crystal diaphragm described in Patent Document 1, a pair of excitation electrodes that excite the vibration part on both main surfaces of a rectangular crystal diaphragm, and a pair that extends these excitation electrodes to one end of the crystal diaphragm. The extraction electrode is formed.

JP 2004-242132 A

  Such an inverted mesa crystal diaphragm has a stepped wall connecting the vibrating part and the outer frame part, and the lead electrode may be disconnected at the edge of the stepped wall. In particular, since the quartz crystal plate is an anisotropic piezoelectric crystal, when wet etching is performed to form a quartz plate having an inverted mesa structure, the etching rate is increased by the crystal axis (the direction of the quartz crystal plate). Different. For example, in the case of an AT-cut quartz diaphragm, a new axis shifted by θ ° from the Z axis is referred to as Z ′, and a new axis shifted from the Y axis by θ ° is referred to as Y ′. The early order is Z ′> + X> −X> Y ′, and the etching rate varies depending on each crystal axis.

  For this reason, the step wall formed by wet etching has a different inclination angle depending on the crystal axis, so that a sharp ridge portion and an obtuse ridge portion are mixed, and disconnection of the extraction electrode in the step wall having an acute ridge portion The rate was extremely high.

  In order to solve such a problem, in Patent Document 1, an electrode material is further evaporated from the upper surface on the ridge portion of the step wall connecting the vibrating portion and the outer frame portion on which the extraction electrode is formed, and the electrode around the step wall is formed. We propose a configuration that avoids the risk of disconnection by making the thickness of the material thick.

  However, in the configuration of Patent Document 1, it is necessary to form the electrode twice, which not only leads to an increase in cost, but also has new problems such as an adverse effect of a shift when forming a partial upper electrode. It was happening.

  SUMMARY OF THE INVENTION In order to solve the above-described problems, an object of the present invention is to provide a quartz diaphragm having a more reliable lead electrode wiring structure that is less likely to cause disconnection at a lower cost, and a quartz vibrating device.

  In order to achieve the above object, a plate-like thin-walled vibration part formed in the center, a thick-walled outer frame part formed on the outer periphery of the vibration part, the periphery of the vibration part, and the outer frame part An AT-cut quartz crystal plate having a stepped wall connecting the at least one pair, and at least a pair of excitation electrodes formed on both main surfaces of the vibrating part of the quartz crystal plate, and connected to each of the excitation electrodes. And at least a pair of extraction electrodes extending to a part of the outer frame portion, and a stepped wall portion having a concavo-convex surface is formed in a portion of the step wall of the crystal diaphragm where the extraction electrode passes. Has been.

  According to the configuration of the present invention, by forming the extraction electrode on the uneven surface stepped wall portion, the surface area of the extraction electrode increases, the probability of connection by the extraction electrode on the step wall increases, and the conduction resistance in this region decreases. It is suppressed. Even if a stress is generated on the extraction electrode due to the difference in thermal expansion between the crystal and the extraction electrode at the ridge portion of the step wall, the disconnection at the extraction electrode in the uneven surface step wall is difficult to spread. By forming an uneven surface step wall on the step wall of the AT-cut quartz diaphragm and forming an extraction electrode on top of this, the step wall is not affected by the crystal axis anisotropy. A region with a more obtuse angle of inclination is always formed at a part of the ridge. For this reason, the edge becomes gentle at the obtuse ridge portion of the stepped wall, and the extraction electrode can be hardly broken.

  Further, in addition to the above-described configuration, the crystal diaphragm and the vibration part are rectangular in plan view, and one of the four corners of the vibration part has a first uneven surface step adjacent to the corner. A wall portion and a second uneven surface step wall portion, and the extraction electrode straddles the first uneven surface step wall portion and the second uneven surface step wall portion adjacent to the one corner portion. And extending from the vibrating portion to a part of the outer frame portion.

  According to the configuration of the present invention, in addition to the above-described effects, the uneven surface-shaped step wall portion is formed on two orthogonal step walls, so that the surface area of the extraction electrode can be further increased and the disconnection at the extraction electrode can be achieved. Is hard to spread. Since the uneven stepped wall portion is formed by two orthogonal step walls, the obtuse ridge portion can be more reliably configured without being further affected by the crystal axis anisotropy. .

  Further, in addition to the above-described configuration, the quartz crystal plate and the vibration part are rectangular in plan view, and the four corner step walls of the vibration part include an R-plane step wall or a C-plane step wall. A part may be formed.

  According to the configuration of the present invention, in addition to the above-described effects, it is possible to suppress the occurrence of cracks in the crystal diaphragm starting from the corner of the step wall and provide a crystal diaphragm having higher impact resistance.

  Further, in addition to the above-described configuration, the quartz crystal plate and the vibration part are rectangular in plan view, and the four corner step walls of the vibration part include an R-plane step wall or a C-plane step wall. A first uneven surface step wall portion and a second uneven surface step wall portion adjacent to the corner portion are formed in one of the four corner portions of the vibration portion, The extraction electrode has a first uneven surface stepped wall portion, an R surface stepped wall portion and a second uneven surface stepped wall portion adjacent to the one corner portion, or a first uneven portion adjacent to the one corner portion. It may extend from the vibrating part to a part of the outer frame part across the planar stepped wall part, the C-shaped stepped wall part, and the second uneven surface shaped stepped wall part.

  According to the configuration of the present invention, in addition to the above-described effects, an uneven surface step wall portion is formed on two orthogonal step walls, and the extraction electrode includes an R surface shape or a C surface step wall portion. Since it is formed, the surface area of the extraction electrode can be further increased, and disconnection at the extraction electrode is difficult to spread. An uneven surface-shaped step wall portion is formed on two orthogonal step walls, and an extraction electrode is formed including an R-plane or C-plane step wall portion, so that the influence of the crystal axis anisotropy of the crystal is affected. Further, the obtuse ridge portion can be more reliably configured. It is possible to provide a quartz plate having higher impact resistance by suppressing the occurrence of cracks in the quartz plate starting from the corner of the step wall.

  Further, in addition to the above-described configuration, the uneven surface stepped wall portion may form an uneven surface only in the plate width direction orthogonal to the plate thickness direction of the crystal diaphragm.

  According to the configuration of the present invention, in addition to the above-described effects, the uneven surface-shaped stepped wall portion is formed with the uneven surface only in the plate width direction orthogonal to the plate thickness direction of the quartz crystal vibration plate. In the extension path of the extraction electrode to the outer frame portion, the risk of disconnection due to the ridge portion constituted by the uneven surface step portion itself is suppressed.

  Further, a quartz crystal comprising the above-described quartz diaphragm, a first sealing body that holds the quartz diaphragm, and a second sealing body that covers the quartz diaphragm held by the first sealing body. Applicable to vibrating devices.

  According to the configuration of the present invention, in addition to the above-described effects, a crystal resonator device on which the above-described superior crystal plate is mounted can be obtained.

  According to the present invention, it is possible to provide a quartz crystal vibrating plate and a quartz crystal vibrating device having a more reliable lead electrode wiring structure in which disconnection is less likely to occur at a lower cost.

It is the perspective view which showed schematic structure of the crystal diaphragm concerning the 1st Embodiment of this invention. It is a top view of FIG. It is a bottom view of FIG. FIG. 2 is a cross-sectional view illustrating a schematic configuration of a crystal resonator on which the crystal diaphragm of FIG. 1 is mounted. It is the schematic diagram which showed the modification of the 1st Embodiment of this invention. It is the perspective view which showed schematic structure of the quartz-crystal diaphragm concerning the 2nd Embodiment of this invention. FIG. 7 is a plan view of FIG. 6. FIG. 7 is a bottom view of FIG. 6.

  Embodiments of the present invention will be described below with reference to the drawings. In the first embodiment of the present invention shown below, the case where the present invention is applied to a crystal resonator as a crystal vibrating device is shown, and in the second embodiment, the case where the present invention is applied to a crystal filter is shown. .

(First embodiment)
In the crystal unit 1 according to the present embodiment, as shown in FIG. 4, a crystal diaphragm 2, a base substrate 3 (first sealing body referred to in the present invention) that holds the crystal diaphragm 2, and a base substrate 3 is provided with a lid 4 (second sealing body referred to in the present invention) for hermetically sealing the quartz crystal diaphragm 2 held by 3.

−Configuration of crystal diaphragm 2−
As shown in FIG. 1, the crystal diaphragm 2 is made of an AT-cut quartz substrate, has a rectangular shape in plan view, and has a plate-like rectangular parallelepiped shape. The long side in plan view is parallel to the X axis in the crystal axis, and the plan view is short. The side is configured to be parallel to the Z ′ axis inclined at a predetermined angle from Z in the crystal axis. On both main surfaces of the substrate of the crystal diaphragm 2, concave portions 21 and 22 having a rectangular shape in plan view are formed in the center of the plate surface in order to cope with the high frequency of the crystal diaphragm 2. In the center of the surface, there is a thin vibrating portion 23, a thick outer frame portion 24 formed on the outer periphery of the vibrating portion 23, and step walls 25 and 26 that connect the periphery of the vibrating portion 23 and the outer frame portion 24. doing. In addition, the concave portions 21 and 22 having a rectangular shape in plan view are configured such that each side is parallel to the X axis and the Z ′ axis in the crystal axis so as to be parallel to each side of the crystal diaphragm 2, for example. The recesses 21 and 22 are formed of a chromium and gold (Cr—Au) film in which windows corresponding to the recesses 21 and 22 are formed by using a photolithography technique, and only the window portions are fluorine-based. A recess having a desired depth can be formed by performing wet etching by immersing in the etching solution. Thereby, the thin vibration part 23, the thick outer frame part 24, and the level | step difference walls 25 and 26 can be comprised with respect to the crystal diaphragm 2. FIG.

  The crystal diaphragm 2 (outer frame portion 24) has a first side 241 and a second side 242 that are two opposing sides, and a third side that is two opposing sides in a direction orthogonal to these sides. 243 and the fourth side 244. At this time, the first side 241 and the second side 242 are configured to be parallel to the Z ′ axis, and face each other at one end and the other end in the X-axis direction of the crystal diaphragm 2.

  At the four corners of the crystal diaphragm 2 (outer frame portion 24), corner portions 245, 246, 247, and 248 are provided. At this time, one end portion of the first side 241 becomes the corner portion 245, the other end portion of the first side 241 becomes the corner portion 246, and one end portion of the second side 242 of the crystal diaphragm 2 (outer frame portion 24). Are the corner portions 247 and the other end portions of the second sides 242 are corner portions 248.

  In the concave portion 21 on one main surface of the crystal diaphragm 2, a parallel first stepped wall 251 that is close to the first side 241 of the crystal diaphragm 2 and a parallel first step wall 251 that is close to the second side 242 of the crystal diaphragm 2. Two step walls 252, a parallel third step wall 253 proximate to the third side 243 of the crystal diaphragm 2, and a parallel fourth step wall 254 proximate to the fourth side 244 of the crystal diaphragm 2. ing. At this time, the first step wall 251 and the second step wall 252 face each other, the third step wall 253 and the fourth step wall 254 face each other, and the first step wall 251 and the second step wall 252 are The third step wall 253 and the fourth step wall 254 are arranged and configured to be orthogonal to each other.

  At the four corners of the recess 21 of the quartz crystal plate 2, there are R-shaped stepped walls 255, 2556, 257, and 258 formed in an arc shape. At this time, one end portion of the first step wall 251 of the recess 21 becomes the R-plane step wall portion 255, the other end portion of the first step wall 251 becomes the R-plane step wall portion 256, and the second portion of the recess 21. One end portion of the step wall 252 is an R-plane step wall portion 257, and the other end portion of the second step wall 252 is an R-plane step wall portion 258. The first step wall 251 and the second step wall 252 are configured to be parallel to the Z ′ axis. In addition, you may comprise this R surface stepped wall part as a C surface stepped wall part formed in linear form.

  A portion of the first step wall 251 and a portion of the fourth step wall 254 adjacent to the R-plane step wall 255 which is one corner of the recess 21 of the crystal plate 2 are provided on the plate of the crystal plate 2. First uneven surface stepped wall portion 2591 and second uneven surface formed with uneven surfaces meandering only in the plate width direction orthogonal to the thickness direction (the respective width directions of the first step wall 251 and the fourth step wall 254). The step-shaped wall portion 2592 is formed. In addition, about this uneven surface, you may comprise as what wobbled only in the plate | board thickness direction of the crystal diaphragm, or what formed the unevenness | corrugation in both the plate | board thickness direction and the plate | board width direction. Further, in this embodiment, the uneven surface stepped wall portion is formed on a part of two sides sandwiching the corner R surface stepped wall portion. However, as shown in FIG. It may be formed on the entire two sides except for the corner area. As shown in FIG. 5 (b), it may be formed only on a part of one side where an extraction electrode to be described later extends, or an extraction electrode to be described later is extended as shown in FIG. 5 (c). You may form only in the whole except the corner part of 1 side. As shown in FIG.5 (d), you may comprise in the 4 side perimeter except a corner part.

  In the recess 22 of the other main surface of the quartz crystal plate 2, a parallel fifth step wall 261 that is close to the first side 241 of the crystal plate 2 and a parallel second step 242 that is close to the second side 242 of the crystal plate 2. 6 step walls 262, a parallel seventh step wall 263 close to the third side 243 of the crystal diaphragm 2, and a parallel eighth step wall 264 close to the fourth side 244 of the crystal diaphragm 2 ing. At this time, the fifth step wall 261 and the sixth step wall 262 face each other, the seventh step wall 263 and the eighth step wall 264 face each other, and the fifth step wall 261 and the sixth step wall 262 are The seventh step wall 263 and the eighth step wall 264 are arranged and configured to be orthogonal to each other.

  At the four corners of the concave portion 22 of the crystal diaphragm 2, there are R-shaped stepped walls 265, 266, 267, 268 formed in an arc shape. At this time, one end portion of the fifth step wall 261 of the recess 22 becomes the R-plane step wall portion 265, the other end portion of the fifth step wall 261 becomes the R-plane step wall portion 266, and the sixth of the recess 22 One end portion of the step wall 262 is an R-plane step wall portion 267, and the other end portion of the sixth step wall 262 is an R-plane step wall portion 268. The fifth step wall 261 and the sixth step wall 262 are configured to be parallel to the Z ′ axis. In addition, you may comprise this R surface stepped wall part as a C surface stepped wall part formed in linear form.

  A part of the fifth step wall 261 and a part of the seventh step wall 263 adjacent to the R-plane step wall 266 that is one corner of the recess 22 of the crystal plate 2 are disposed on the plate of the crystal plate 2. A third uneven surface step wall 2691 and a fourth uneven surface on which uneven surfaces meandering only in the plate width direction (the respective width directions of the fifth step wall 261 and the seventh step wall 263) perpendicular to the thickness direction are formed. A step-shaped wall portion 2692 is formed. In addition, you may comprise this uneven surface as what meandered only in the plate | board thickness direction of the crystal diaphragm, and formed the unevenness | corrugation in both the plate | board thickness direction and the plate | board width direction. Further, in this embodiment, the uneven surface stepped wall portion is formed on a part of two sides sandwiching the corner R surface stepped wall portion, but as shown in FIG. 5, the R surface stepped wall portion is sandwiched. In addition, it may be formed on the entire two sides except for the corner area. It may be formed only on a part of one side where a later-described extraction electrode extends or on all except a corner, or may be formed on the entire periphery of four sides excluding a corner.

  A first excitation electrode 201 is formed on one main surface of the crystal diaphragm 2 in the vicinity of the inner center of the recess 21 (vibration portion 23), and on the other main surface of the crystal diaphragm 2 in the vicinity of the inner center of the recess 22 (vibration portion 23). ) Is formed with the second excitation electrode 202. The first excitation electrode 201 and the second excitation electrode 202 are electrically connected to the external electrode (in this embodiment, the electrode pads 33 and 34 of the base substrate 3) in order to be mechanically joined to the first extraction electrode 203 and the second excitation electrode 203. The lead electrode 204 extends from the vibrating portion 23 to a part of the outer frame portion 24 via the step wall 25.

  The first extraction electrode 203 extends the first excitation electrode 201 only in the vicinity of the corner portion 245 that is one end portion of the first side 241 of the crystal diaphragm 2 (outer frame portion 24) (only on the first side side). And is formed at one of the two corners at both ends of the first side). More specifically, the first extraction electrode 203 includes a first front extraction electrode 2031 extending in a section from the vibrating portion 23 to the front of the step wall 25 and a section from the step wall 25 to the outer frame section 24. The first rear extraction electrode 2032 is provided. The first front extraction electrode 2031 is connected to the corner portion of the first excitation electrode 201 and extends from the corner portion toward the R-plane stepped wall portion 255. The first rear extraction electrode 2032 is connected to the end portion of the first front extraction electrode 2031, and the first uneven surface step wall portion 2591, the R surface step wall portion 255, and the second uneven surface shape from the end portion. By extending over the upper surface of the step wall portion 2592, it extends to a partial region of the upper surface of the outer frame portion 24 leading to the corner portion 245 through the step wall 25.

  The second extraction electrode 204 extends the second excitation electrode 202 only in the vicinity of the corner portion 246 which is the other end portion of the first side 241 of the crystal diaphragm 2 (outer frame portion 24) (only on the first side side). And is formed at one of the two corners at both ends of the first side). More specifically, the second extraction electrode 204 includes a second front extraction electrode 2041 extending in a section from the vibrating portion 23 to the front of the step wall 25 and a section from the step wall 25 to the outer frame section 24. It has the 2nd latter extraction electrode 2042 to take out. The second front extraction electrode 2041 is connected to a corner of the second excitation electrode 202 and extends from the corner toward the R-plane stepped wall 266. The second rear extraction electrode 2042 is connected to the end of the second front extraction electrode 2041, and from the end, the third uneven surface stepped wall portion 2691, the R surface stepped wall portion 266, and the fourth uneven surface shape are formed. By being formed over the upper surface of the step wall portion 2692, it extends to a partial region of the upper surface of the outer frame portion 24 leading to the corner portion 246 through the step wall 25.

  With the above configuration, two orthogonal stepped walls of the AT-cut crystal diaphragm 2 span the upper surfaces of the first uneven surface step wall portion 2591, the R surface step wall portion 255, and the second uneven surface step wall portion 2592. The first rear extraction electrode 2032 is formed, and the third uneven surface step wall portion 2691, the R surface step wall portion 266, and the fourth uneven surface step are formed on two orthogonal step walls of the AT-cut quartz crystal plate 2. A second rear extraction electrode 2042 is formed across the upper surface of the wall portion 2692.

  For this reason, the surface area of each extraction electrode increases, and the probability of connection by each extraction electrode in the step walls 25 and 26 increases. A decrease in the conduction resistance in this region is suppressed. Even if stress is generated on each extraction electrode due to a difference in thermal expansion between the crystal and the extraction electrode at the ridges of the step walls 25 and 26, the disconnection at each extraction electrode in each uneven surface stepped wall portion is difficult to spread. . In addition, by forming an uneven surface that meanders the uneven surface stepped wall portions 2591, 2592, 2691, and 2992 only in the plate width direction of the crystal vibration plate 2, each extraction electrode from the vibration portion 23 to the outer frame portion 24 is formed. In the extending path, the risk of disconnection due to the ridge portion constituted by the uneven surface step portion itself is suppressed.

  In addition, when the step wall is formed by wet etching the AT-cut quartz crystal diaphragm 2, the inclination angle of the step wall varies depending on the crystal axis anisotropy of the crystal, or the edge of the ridge portion of the step wall is tight. May be affected. However, a more obtuse ridge portion can be reliably configured, and the obtuse ridge portion of the step wall has a gentle edge, so that the extraction electrode is less likely to be disconnected.

  In addition, the four corners of the step wall have R-shaped stepped walls 255, 256, 257, 258, 265, 266, 267, and 268 formed in an arc shape. It is possible to suppress the occurrence of cracks in the quartz crystal plate 2 and to provide the quartz plate 2 having higher impact resistance.

  The first excitation electrode 201, the second excitation electrode 202, the first extraction electrode 203, and the second extraction electrode 204 are formed by a photolithography method. For example, chromium, gold (Cr—Au) is formed from the substrate side. Or in the order of nickel and gold (Ni—Au).

  The quartz diaphragm 2 of the present embodiment discloses a so-called bi-reverse mesa shape in which the concave portion 21 is formed on one main surface of the quartz diaphragm and the concave portion 22 is formed on the other main surface of the quartz diaphragm. However, the present invention can also be applied to a so-called plano inverted mesa shape in which a concave portion is formed only on one of the principal surface or the other principal surface of the crystal diaphragm 2.

-Configuration of base substrate 3-
As shown in FIG. 4, the base substrate 3 is formed in a box-like body including a bottom portion 31 and a wall portion 32 extending upward from the bottom portion 31. The base substrate 3 has a rectangular parallelepiped ceramic material laminated on a single plate made of a ceramic material in a rectangular shape in plan view and is integrally fired in a concave shape.

  The wall portion 32 is formed along the outer periphery of the surface of the bottom portion 31. The upper surface of the wall part 32 is a joining area | region with a cover body, The sealing member (for example, metallized layer, a metal ring material, etc.) 321 for joining with a cover body is provided in this joining area | region.

  In addition, a plurality of electrode pads 33 and 34 (partially connected to the first excitation electrode 201 and the second excitation electrode 202 of the quartz diaphragm 2 are respectively provided on the bottom 31 of the base substrate 3. Only shown). These electrode pads are electrically connected to terminal electrodes 35 and 36 formed on the outer peripheral back surface of the base substrate 3, respectively. These terminal electrodes are connected to external parts and external devices. These terminal electrodes and electrode pads are formed by printing a metallized material such as tungsten or molybdenum and then firing integrally with the base substrate 3. Some of these terminal electrodes and electrode pads are formed by forming nickel plating on the metallized upper portion and forming gold plating on the upper portion thereof.

-Configuration of lid 4-
The lid is made of, for example, a metal material or a ceramic material, and is formed into a single plate. This lid has a sealing material (a brazing material, a plating material, a glass material, etc.) formed on the lower surface.

-Configuration of crystal unit 1-
One end portion of the first side 241 of the crystal diaphragm 2 is formed at the corner portion 245 of the first rear extraction electrode 2032, the electrode pad 33 of the base substrate 3, and the other end portion of the first side 241 of the crystal diaphragm 2. The second rear extraction electrode 2042 formed at the corner portion 246 and the electrode pad 34 of the base substrate 3 are electrically and mechanically joined by the joining member B, and only the first side 241 of the crystal vibrating plate 2 is attached to the base substrate 3. One piece is held. In this embodiment, a conductive resin bonding agent made of silicone resin or the like is used as the bonding member B. In addition, as this joining member B, you may use the conductive bump which consists of not only a conductive resin bonding agent but a brazing material or a metal material.

  In this crystal unit 1, a base substrate 3 (substrate in the present invention) and a lid 4 are joined to form a package, and the base substrate 3 and the lid 4 are joined to form an internal space of the package. The The base substrate 3 (substrate in the present invention) and the lid 4 are joined by a welding technique such as a seam or beam, or an atmosphere heating technique such as a glass sealing material or a metal brazing material. At this time, as shown in FIG. 4, the base substrate 3 (the substrate in the present invention) and the lid 4 are joined together with the crystal diaphragm 2 held and mounted on the base substrate 3. The crystal diaphragm 2 is hermetically sealed in the internal space, and the crystal resonator 1 (crystal resonator device) is completed.

(Second Embodiment)
In the crystal filter according to this example, the crystal filter plate 5 (the crystal vibration plate referred to in the present invention), a base substrate (not shown) that holds the crystal filter plate 5, and the crystal filter plate 5 that is held on the base substrate. And a lid (not shown) for hermetically sealing. Hereinafter, the crystal filter according to the present example will be described focusing on the crystal filter plate 5 different from the above embodiment.

-Configuration of crystal filter plate 5-
As shown in FIG. 6, the quartz filter plate 5 is made of an AT-cut quartz substrate, has a rectangular rectangular shape in plan view, has a plate-like rectangular parallelepiped shape, and has a Z ′ axis whose long side in plan view is inclined at a predetermined angle from Z in the crystal axis. They are parallel, and the short side in plan view is configured to be parallel to the X axis in the crystal axis. On the other main surface of the quartz filter plate 5, a rectangular recess 52 in plan view is formed in the center of the plate surface in order to cope with the high frequency of the quartz filter plate 5. Includes a thin vibrating portion 53, a thick outer frame portion 54 formed on the outer periphery of the vibrating portion 53, and a stepped wall 56 that connects the periphery of the vibrating portion 53 and the outer frame portion 54. In addition, the rectangular recess 52 in plan view is configured such that each side is parallel to the X axis and the Z ′ axis in the crystal axis so as to be parallel to each side of the crystal filter plate 5, for example. Such a recess 52 is formed by using a photolithographic technique to form a chromium and gold (Cr—Au) film in which a window corresponding to the recess 52 is formed, and only the window is used as a fluorine-based etching solution. By dipping and wet etching, a recess having a desired depth can be formed. Thereby, the thin vibration part 53, the thick outer frame part 54, and the step wall 56 can be configured with respect to the crystal filter plate 5.

  The crystal filter plate 5 (outer frame portion 54) has a first side 541 and a second side 542 which are two opposite sides, and a third side which is two opposite sides in a direction orthogonal to these sides. 543 and a fourth side 544. At this time, the first side 541 and the second side 542 are configured to be parallel to the X-axis, and face each other at one end and the other end in the Z′-axis direction of the crystal filter plate 5.

  The four corners of the quartz filter plate 5 (outer frame portion 54) have corner portions 545, 546, 547, and 548. At this time, one end portion of the first side 541 becomes the corner portion 545, the other end portion of the first side 541 becomes the corner portion 546, and one end portion of the second side 542 of the crystal filter plate 5 (outer frame portion 54). Are arranged and configured such that the other end portion of the second side 542 becomes the corner portion 548.

  In the recess 52 on the other main surface of the crystal filter plate 5, a parallel fifth step wall 561 that is close to the first side 541 of the crystal filter plate 5 and a parallel second step that is close to the second side 542 of the crystal filter plate 5. 6 step walls 562, a parallel seventh step wall 563 close to the third side 543 of the crystal filter plate 5, and a parallel eighth step wall 564 close to the fourth side 544 of the crystal filter plate 5. ing. At this time, the fifth step wall 561 and the sixth step wall 562 face each other, the seventh step wall 563 and the eighth step wall 564 face each other, and the fifth step wall 561 and the sixth step wall 562 are The seventh step wall 563 and the eighth step wall 564 are arranged and configured to be orthogonal to each other.

  C-shaped stepped wall portions 565, 566, 567, and 568 formed linearly are provided at the four corners of the recess 52 of the quartz filter plate 5. At this time, one end portion of the fifth step wall 561 of the recess 52 becomes a C-plane stepped wall portion 565, the other end portion of the fifth step wall 561 becomes a C-plane stepped wall portion 566, and the sixth of the recess 52 One end portion of the step wall 562 is a C-plane stepped wall portion 567, and the other end portion of the sixth step wall 562 is a C-plane stepped wall portion 568. The fifth step wall 561 and the sixth step wall 562 are configured to be parallel to the X axis. In addition, you may comprise this C surface-shaped step wall part as an R surface step-shaped wall part formed in circular arc shape.

  A portion of the fifth step wall 561 and a portion of the seventh step wall 563 adjacent to the C-plane step wall portion 566 that is one corner of the recess 52 of the crystal filter plate 5 are disposed on the plate of the crystal filter plate 5. First uneven surface stepped wall portion 5691 and second uneven surface formed with uneven surfaces meandering only in the plate width direction orthogonal to the thickness direction (the respective width directions of the fifth step wall 561 and the seventh step wall 563) And a stepped wall portion 5692. A part of the sixth step wall 562 and a part of the eighth step wall 564 adjacent to the C-plane step wall 567 which is one corner of the recess 52 of the crystal filter plate 5 are disposed on the plate of the crystal filter plate 5. A third uneven surface stepped wall portion 5673 and a fourth uneven surface formed with uneven surfaces meandering only in the plate width direction (the respective width directions of the sixth step wall 562 and the eighth step wall 564) perpendicular to the thickness direction. A stepped wall portion 5694 is formed. In addition, you may comprise this uneven surface as what meandered only in the plate | board thickness direction of the crystal filter board, and formed the unevenness | corrugation in both the plate | board thickness direction and plate | board width direction. In this embodiment, the uneven surface stepped wall portion is formed on a part of two sides sandwiching the C-plane step wall portion at the corner, but the corner region is sandwiched between the C-surface step wall portion. It may be formed on the entire two sides except. It may be formed only on a part of one side where a later-described extraction electrode extends or on all except a corner, or may be formed on the entire periphery of four sides excluding a corner.

  A rectangular first electrode 501 and a second electrode 502 are arranged along the Z ′ axis with a predetermined gap region G in between near the center of the inside of one main surface of the quartz filter plate 5 (vibrating portion 53). It has the divided electrode (excitation electrode as referred to in the present invention) formed. A rectangular common electrode 503 (on the other main surface of the quartz filter plate 5 near the inner center of the recess 52 (vibrating portion 53) and opposed to the divided electrodes (first electrode 501 and second electrode 502) ( Excitation electrode as used in the present invention is formed. The first electrode 501 and the second electrode 502 are part of the outer frame portion 54 from the vibrating portion 53 by the first extraction electrode 504 and the second extraction electrode 505 in order to be electromechanically joined to an external electrode (not shown). It is extended to. The common electrode 503 is part of the outer frame portion 54 via the step wall 56 from the vibrating portion 53 by the third extraction electrode 506 and the fourth extraction electrode 507 in order to be electromechanically joined to an external electrode (not shown). Each is extended to.

  The first extraction electrode 504 extends the first electrode 501 only in the vicinity of the corner portion 545 that is one end portion of the first side 541 of the crystal filter plate 5 (outer frame portion 54) (extends only to the first side). And is formed at one of the two corners at both ends of the first side). More specifically, the first extraction electrode 504 includes a first front extraction electrode 5041 extending in a section from the vibrating portion 53 to a region before the region corresponding to the step wall 56 formed on the other main surface, and a step wall And a first rear extraction electrode 5042 extending from a region corresponding to 56 to the outer frame portion 54. The first front extraction electrode 5041 is connected to the central part of the parallel side 5011 close to the first side 541 of the crystal filter plate 5 among the sides of the first electrode 501, and the first electrode 501 from the central part. And the second electrode 502 extend along the crystal axis direction (in this embodiment, the Z ′ axis) formed side by side. The first rear extraction electrode 5042 is connected to the end of the first front extraction electrode 5041, and the first electrode 501 and the second electrode 502 are formed side by side in the region from the end to the outer frame portion 54. It extends along the crystal axis direction (X axis in this embodiment) orthogonal to the crystal axis direction, and extends to a partial region of the upper surface of the outer frame portion 54 leading to the corner portion 546.

  The second extraction electrode 505 extends the second excitation electrode 502 only in the vicinity of the corner portion 548 which is the other end portion of the second side 542 of the crystal filter plate 5 (outer frame portion 54) (only on the second side side). And is formed at one of the two corners at both ends of the second side). More specifically, the second extraction electrode 505 includes a second front extraction electrode 5051 extending in a section from the vibrating portion 53 to a region before the region corresponding to the step wall 56 formed on the other main surface, and a step wall And a second rear extraction electrode 5052 extending from a region corresponding to 56 to the outer frame portion 54. The second front extraction electrode 5051 is connected to the central part of the parallel side 5021 adjacent to the second side 542 of the crystal filter plate 5 among the sides of the second electrode 502, and the first electrode 501 from the central part. And the second electrode 502 extend along the crystal axis direction (in this embodiment, the Z ′ axis) formed side by side. The second rear extraction electrode 5052 is connected to the end of the second front extraction electrode 5051, and the first electrode 501 and the second electrode 502 are formed side by side in the region from the end to the outer frame portion 54. It extends along the crystal axis direction orthogonal to the crystal axis direction (in this embodiment, the X axis), and extends to a partial region of the upper surface of the outer frame portion 54 leading to the corner portion 548.

  The third extraction electrode 506 extends the common electrode 503 only in the vicinity of the corner portion 546 that is the other end portion of the first side 541 of the crystal filter plate 5 (outer frame portion 54) (extends only to the first side side). And is formed at one of the two corners at both ends of the first side). More specifically, the third extraction electrode 506 includes a third front extraction electrode 5061 extending in a section from the vibrating portion 53 to the front of the step wall 56 and a section from the step wall 56 to the outer frame section 54. And a third rear extraction electrode 5062 to be taken out. The third front extraction electrode 5061 is connected to a corner 5031 of the common electrode 503, and a crystal axis perpendicular to the crystal axis direction in which the first electrode 501 and the second electrode 502 are formed side by side from the corner. It extends along the direction (X axis in this embodiment). The third rear extraction electrode 5062 is connected to the end portion of the third front extraction electrode 5061, and the crystal axis direction (in this embodiment) in which the first electrode 501 and the second electrode 502 are formed side by side from the end portion. Z′-axis) and extending over the upper surfaces of the first uneven surface stepped wall portion 5691, the C surface stepped wall portion 566, and the second uneven surface stepped wall portion 5692. It extends to a partial region of the upper surface of the outer frame portion 54 to the corner portion 546 via the wall 56.

  The fourth extraction electrode 507 extends the common electrode 503 only in the vicinity of the corner portion 547 that is one end portion of the second side 542 of the crystal filter plate 5 (outer frame portion 54) (extends only to the second side). And is formed at one of the two corners at both ends of the second side). More specifically, the fourth extraction electrode 507 includes a fourth front extraction electrode 5071 extending in a section from the vibrating portion 53 to the front of the step wall 56, and a section from the step wall 56 to the outer frame section 54. And a fourth rear extraction electrode 5072 to be taken out. The fourth front extraction electrode 5071 is connected to the corner 5032 of the common electrode 503, and the crystal axis direction orthogonal to the crystal axis direction in which the first electrode 501 and the second electrode 502 are formed side by side from the corner. It extends along the X axis in this embodiment. The fourth rear extraction electrode 5072 is connected to the end portion of the fourth front extraction electrode 5071, and the crystal axis direction (in this embodiment) in which the first electrode 501 and the second electrode 502 are formed side by side from the end portion. Z′-axis) and extending over the upper surfaces of the third uneven surface stepped wall portion 5669, the C surface stepped wall portion 567, and the fourth uneven surface stepped wall portion 5694. It extends to a partial region of the upper surface of the outer frame portion 54 to the corner portion 547 via the wall 56.

  With the above configuration, two orthogonal stepped walls of the AT-cut quartz filter plate 5 straddle the upper surfaces of the first uneven surface stepped wall portion 5691, the C surface stepped wall portion 566, and the second uneven surfaced stepped wall portion 5692. The third post-stage extraction electrode 5062 is formed, and the third uneven surface step wall portion 5673, the C surface step wall portion 567, and the fourth uneven surface step are formed on two orthogonal step walls of the AT-cut quartz filter plate 5. A fourth rear extraction electrode 5072 is formed across the upper surface of the wall portion 5694.

  For this reason, the surface area of each extraction electrode increases, and the probability of connection by each extraction electrode in the step wall 56 increases. A decrease in the conduction resistance in this region is suppressed. Even if a stress is generated on each extraction electrode due to a difference in thermal expansion between the crystal and the extraction electrode at the ridge portion of the step wall 56, the disconnection at each extraction electrode in each uneven surface step wall is difficult to spread. In addition, by forming an uneven surface that meanders the uneven surface stepped wall portions 5691, 5692, 5663, and 5694 only in the plate width direction of the crystal filter plate 5, each extraction electrode from the vibrating portion 53 to the outer frame portion 54 is formed. In the extending path, the risk of disconnection due to the ridge portion constituted by the uneven surface step portion itself is suppressed.

  Further, when the step wall is formed by wet etching the AT-cut crystal filter plate 5, the inclination angle of the step wall differs due to the crystal axis anisotropy of the crystal, or the edge of the ridge portion of the step wall is tight. May be affected. However, a more obtuse ridge portion can be reliably configured, and the obtuse ridge portion of the step wall has a gentle edge, so that the extraction electrode is less likely to be disconnected.

  Further, since the four corner portions of the step wall have C-shaped step wall portions 565, 566, 567, and 568 formed in a straight line, cracks of the crystal filter plate 5 starting from these four corners are obtained. Generation | occurrence | production can be suppressed and the quartz filter board 5 with higher impact resistance can be provided.

  Further, the extending directions of the first front extraction electrode 5041 and the second front extraction electrode 5051 are set so that the first electrode 501 and the first electrode 501 extend from the center of each side close to the outer periphery of the crystal filter plate of the first electrode 501 and the second electrode 502. By extending along the crystal axis direction (in this embodiment, the Z ′ axis) in which the two electrodes 502 are formed side by side, the occurrence of twist mode spurious can be suppressed. Furthermore, as described above, the extending direction of the third pre-stage extraction electrode 5061 and the fourth pre-stage extraction electrode 5071 is the crystal axis direction orthogonal to the crystal axis direction in which the first electrode 501 and the second electrode 502 are formed side by side ( By extending along the X axis in this embodiment, the first front extraction electrode 5041, the second front extraction electrode 5051, and the vibrating portion 53 of the crystal filter plate 5 are not disposed opposite to each other. The filter characteristics are not adversely affected.

  The quartz filter plate 5 of the present embodiment discloses a so-called plano inverted mesa shape in which the recess 52 is formed only on the other principal surface of the quartz filter plate. The present invention can also be applied to a so-called bi-inverted mesa shape in which a concave portion is formed on the main surface. In addition, although two paths of the third extraction electrode 506 and the fourth extraction electrode 507 are configured as the extraction electrode of the common electrode 503 of this embodiment, only one of the paths may be used.

  The first electrode 501, the second electrode 502, the first extraction electrode 504, the second extraction electrode 505, the third extraction electrode 506, and the fourth extraction electrode 507 are formed by photolithography, for example, aluminum (Al) Single layer, chromium, silver (Cr-Ag), or nickel, silver (Ni-Ag) are laminated in this order.

  The embodiments of the present invention described above are all examples embodying the present invention, and are not of a nature that limits the technical scope of the present invention.

  The present invention can also be applied to crystal vibrating devices such as a crystal resonator, a crystal filter, and a crystal oscillator.

DESCRIPTION OF SYMBOLS 1 Crystal resonator 2 Crystal diaphragm 3 Base substrate 4 Lid 5 Crystal filter board B Bonding member

Claims (6)

A plate-like AT having a thin vibrating portion formed in the center, a thick outer frame portion formed on the outer periphery of the vibrating portion, and a step wall connecting the periphery of the vibrating portion and the outer frame portion Cut crystal diaphragm,
At least a pair of excitation electrodes formed on both main surfaces of the vibration part of the crystal diaphragm;
At least a pair of extraction electrodes connected to each of the excitation electrodes and extending from the vibrating portion to a part of the outer frame portion;
With
An uneven surface step wall portion is formed in a portion of the step wall of the quartz crystal plate through which the extraction electrode passes.
A quartz crystal diaphragm characterized by that. The crystal diaphragm and the vibration part are rectangular in plan view,
In one of the four corners of the vibration part, a first uneven surface step wall and a second uneven surface step wall adjacent to the corner are formed,
The extraction electrode extends from the vibrating portion to a part of the outer frame portion across the first uneven surface stepped wall portion and the second uneven surface stepped wall portion adjacent to the one corner portion. Yes,
The crystal diaphragm according to claim 1, wherein: The crystal diaphragm and the vibration part are rectangular in plan view,
On the step walls at the four corners of the vibration part, an R-plane step wall or a C-plane step wall is formed.
The crystal diaphragm according to claim 1, wherein: The crystal diaphragm and the vibration part are rectangular in plan view,
On the step walls at the four corners of the vibration part, an R-plane step wall or a C-plane step wall is formed,
In one of the four corners of the vibration part, a first uneven surface step wall and a second uneven surface step wall adjacent to the corner are formed,
The extraction electrode has a first uneven surface stepped wall portion, an R surface stepped wall portion and a second uneven surface stepped wall portion adjacent to the one corner portion, or a first uneven portion adjacent to the one corner portion. A planar stepped wall portion, a C-planar stepped wall portion and a second uneven surface stepped wall portion,
Extending from the vibrating part to a part of the outer frame part,
The crystal diaphragm according to claim 1, wherein: The uneven surface stepped wall portion forms an uneven surface only in the plate width direction orthogonal to the plate thickness direction of the crystal diaphragm,
The quartz crystal diaphragm according to any one of claims 1 to 4, wherein The quartz crystal diaphragm according to any one of claims 1 to 5, a first sealing body that holds the quartz diaphragm, and the quartz diaphragm that is held by the first sealing body are covered. A crystal vibration device comprising a second sealing body.

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