JP2012065000A - Piezoelectric vibration piece, piezoelectric vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration piece and a piezoelectric vibrator in which a short circuit and the like is prevented when they are packaged.SOLUTION: The piezoelectric vibration piece 10 produced by wet etching a piezoelectric raw plate of AT cut has a slit 30 which has long sides in the X axis direction, and mounts 42, 44 arranged between the slit 30 and an end 12 of the piezoelectric vibration piece 10 on the Z' axis side. The end 12 has a first end face 16 and a second end face 20 extending in the X axis direction, and a step. The step is arranged between the first end face 16 and the second end face 20, and has a step in the Z' axis direction.

Description

  The present invention relates to a piezoelectric vibrating piece and a piezoelectric vibrator using the same, and more particularly to a technique that prevents a short circuit between electrodes.

  Conventionally, there is a form in which a piezoelectric vibrating piece is mounted and fixed to a package by applying a conductive adhesive. When the piezoelectric vibrating piece is supported by the conductive adhesive in this way, in the reflow process for curing the conductive adhesive, distortion due to differences in the linear expansion coefficients of the piezoelectric vibrating piece, the package, and the conductive adhesive is fixed. Therefore, there is a problem that the stress from the fixed part to the vibration part adversely affects the vibration. In order to avoid this, a slit is provided between a portion where a conductive adhesive is applied and a vibrating portion (see, for example, Patent Documents 1, 2, and 3).

  In addition, in order to ensure the strength and the like, a recess is formed in the central portion of the piezoelectric vibrating piece to form an inverted mesa type (see, for example, Patent Documents 1 and 2). In recent years, there has been a demand for further downsizing of the inverted mesa type piezoelectric vibrating piece. For the formation of the shape of the inverted mesa type piezoelectric vibrating piece, wet etching with high mass productivity is often employed.

JP 2007-57395 A JP 2005-121628 A Japanese Patent Laid-Open No. 9-326687

  By the way, when an electrode is formed on the piezoelectric vibrating piece whose outer shape is formed by such wet etching, a metal film is previously formed on the entire surface of the piezoelectric vibrating piece by sputtering or the like, and a resist film is applied to the metal film. Next, the resist film is exposed using a photomask corresponding to the shape of the excitation electrode and the extraction electrode. At this time, the resist film is exposed on both sides of the piezoelectric vibrating piece. Then, the exposed resist film is removed, the portion where the metal film is exposed is removed by etching, and the resist film is removed to form the excitation electrode and the extraction electrode.

  However, since the piezoelectric element plate (crystal element plate) that is a raw material of the piezoelectric vibrating piece has anisotropy in the etching, the etching rate differs depending on the crystal orientation. For this reason, a trough portion that bites into the piezoelectric vibrating piece side is generated in the cross section of the end portion in the Z′-axis direction of the AT-cut quartz crystal substrate. It is possible to form the above-mentioned metal film or resist film in the valley portion, but even if light for exposing the resist film is applied from both sides of the piezoelectric vibrating piece, the valley portion is irradiated with light. Instead, it becomes a shadow. As a result, the metal film formed in the valley portion remains without being etched, which may cause a short circuit between the electrodes.

  Accordingly, the present invention focuses on the above-described problems, and an object thereof is to provide a piezoelectric vibrating piece that prevents a short circuit between electrodes formed on the piezoelectric vibrating piece, and a piezoelectric vibrator using the same.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples.
Application Example 1 A piezoelectric vibrating piece obtained by wet-etching an AT-cut piezoelectric element plate, the slit having a long side in the X-axis direction in the piezoelectric vibrating piece, and the Z ′ axis of the slit and the piezoelectric vibrating piece A mount portion disposed between the first end surface and the second end surface extending in the X-axis direction, and a step portion, and the step portion. Is disposed between the first end face and the second end face and has a step in the Z′-axis direction.

  In the piezoelectric vibrating piece, generally, a metal film is deposited on the entire surface of the piezoelectric vibrating piece, and unnecessary portions of the metal film are removed using photolithography and etching to form electrodes. Then, a trough is formed along the X-axis direction on the first and second end surfaces in contact with the end portion on the Z′-axis side of the piezoelectric vibrating piece due to etching anisotropy. Therefore, since the light for photosensitivity does not reach the valley, the metal film deposited on the valley remains without being etched. On the other hand, a conductive adhesive is connected to the mount portion. At this time, the conductive adhesive may reach the first end surface and the second end surface on the Z′-axis side of the piezoelectric vibrating piece. Therefore, when a conductive adhesive is applied to such a mount portion, the conductive adhesive may be short-circuited by the metal film remaining in the above-described valley portion. However, in the above configuration, the trough formed on the first end surface and the trough formed on the second end surface are divided by the stepped portion. Further, since the step portion has a side extending in the Z′-axis direction from which the metal film has been removed, the metal films remaining in the valley portions are insulated from each other. Therefore, when the conductive adhesive is applied to each of the first end surface side and the second end surface side of the mount portion, the conductive adhesives are not short-circuited via the valley portion, and the piezoelectric vibrating piece is not mounted. Yield can be increased.

  Further, with the above configuration, the path from the mount portion where the extraction electrode is formed and fixed to the substrate or the like to the portion where the excitation electrode is formed can be lengthened. Thereby, the stress from the mount portion to the portion where the excitation electrode is formed is relaxed, and the piezoelectric vibrating piece is suppressed in which the frequency fluctuation due to reflow or aging is suppressed.

Application Example 2 The piezoelectric vibrating piece according to Application Example 1, wherein a second step portion having a long side in the Z-axis direction is disposed on an end surface having a long side in the X-axis direction of the slit. .
Since a trough extending in the X-axis direction is also formed on the end surface having the long side in the X-axis direction of the slit, the conductive adhesive is short-circuited even when the conductive adhesive reaches this end surface. There is a fear. However, by providing a step portion on this end face, it is possible to prevent a short circuit between the conductive adhesives and to increase the yield when mounting the piezoelectric vibrating piece.

[Application Example 3] In the application example 1 or 2, the step portion is a convex portion protruding in the Z′-axis direction from the end portion or a concave portion in which a part of the end portion is notched. Piezoelectric vibrating piece.
Accordingly, the stepped portion can be formed simultaneously with the step of forming the outer shape of the piezoelectric vibrating piece, so that the yield of mounting the piezoelectric vibrating piece can be increased without cost.

  Application Example 4 The present invention includes a pair of extraction electrodes provided on the first end surface side and the second end surface side of the mount portion, respectively, and connected to excitation electrodes formed on the piezoelectric vibrating piece. In any one of the application examples 1 to 3, the pair of extraction electrodes are arranged on the same surface of the piezoelectric vibrating piece by drawing one of the extraction electrodes to the opposite surface. The piezoelectric vibrating piece according to the description.

  When a conductive adhesive is applied to the portion of the mount portion where the extraction electrode is formed, the mount portion simultaneously performs mechanical connection and electrical connection of the piezoelectric vibrating piece. Therefore, the mounting process can be simplified and the cost can be suppressed.

Application Example 5 The piezoelectric vibrating piece includes a thin portion that is thinly etched by wet etching, the thin portion and the mount portion are disposed so as to sandwich the slit, and the excitation electrode includes the thin portion 5. The piezoelectric vibrating piece according to any one of Application Examples 1 to 4, wherein the piezoelectric vibrating piece is disposed in the area.
Thereby, the high frequency of the piezoelectric vibrating piece can be achieved.

[Application Example 6] The piezoelectric vibrating piece according to Application Example 5, wherein the thin-walled portion has a shape that is wet-etched into a thin-walled portion up to the opposite end of the mount portion.
Thereby, since the free end side of the piezoelectric vibrating piece is reduced in weight, it is possible to improve the impact resistance of the piezoelectric vibrating piece after mounting.

[Application Example 7] The piezoelectric vibrating piece according to Application Example 6, wherein the thin-walled portion has a shape that is wet-etched thinly to the end in the X-axis direction of the piezoelectric vibrating piece.
Thereby, the impact resistance of the piezoelectric vibrating piece after mounting can be further enhanced.

Application Example 8 The surface of the piezoelectric vibrating piece according to any one of Application Examples 3 to 7 on which the pair of extraction electrodes is disposed is directed to the substrate side, and the pair of extraction electrodes and the substrate are electrically conductive. A piezoelectric vibrator characterized by being connected through an adhesive.
As a result, a piezoelectric vibrator is obtained in which a short circuit between the conductive adhesives during mounting is prevented.

1A and 1B are schematic views of a piezoelectric vibrator according to the present embodiment, in which FIG. 1A is a plan view, FIG. 1B is a bottom view, and FIG. 1C is a cross-sectional view taken along line AA in FIG. FIG. 1D is a cross-sectional view taken along the line BB of FIG. FIG. 2A shows a simulation result of the end face shape of the quartz substrate, FIG. 2A is a schematic diagram of a piezoelectric vibrating piece (part 1) used for the simulation and a cross-sectional shape taken along the line CC, and FIG. 2B is a piezoelectric vibrating piece used for the simulation. FIG. 2C is a schematic diagram of the piezoelectric vibrating reed (part 2) used for the simulation and a EE line cross-sectional shape. It is a schematic diagram which shows the manufacturing process (outer shape formation process) of a piezoelectric vibrating piece. It is a schematic diagram of the manufacturing process (thin wall portion forming process) of the piezoelectric vibrating piece. It is a schematic diagram of the manufacturing process (electrode formation process) of a piezoelectric vibrating piece. It is a schematic diagram which shows the modification of the level | step-difference part of this embodiment. It is a schematic diagram which shows the modification of the level | step-difference part of this embodiment. It is a schematic diagram which shows the modification of the thin part of this embodiment, Fig.8 (a) is a top view, FIG.8 (b) is a bottom view, FIG.8 (c) is the AA line of Fig.8 (a). Sectional drawing and FIG.8 (d) are the BB sectional drawing of Fig.8 (a). It is a schematic diagram which shows the modification of the thin part of this embodiment, Fig.9 (a) is a top view, FIG.9 (b) is a bottom view, FIG.9 (c) is the AA line of Fig.9 (a). Sectional drawing and FIG.9 (d) are the BB sectional drawing of Fig.9 (a).

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .

  A piezoelectric vibrating piece according to this embodiment is shown in FIG. 1A is a plan view, FIG. 1B is a bottom view, FIG. 1C is a cross-sectional view taken along line AA in FIG. 1A, and FIG. 1D is B in FIG. FIG. The piezoelectric vibrating piece 10 according to the present embodiment uses an AT-cut crystal element plate as a piezoelectric element plate, and has an outer shape formed by wet etching so that the short side is in the X-axis direction and the long side is in the Z′-axis direction. This is an inverted mesa type piezoelectric vibrating piece 10. In addition, the slit 30 and the second slit 31 are simultaneously formed in the step of forming the outer shape by wet etching.

  The second slit 31 extending in the Z′-axis direction divides the end portion 12 on the −Z′-axis side of the piezoelectric vibrating piece 10 into the first end surface 16 and the second end surface 20, and the X-axis direction of the slit 30. The end face 32a having the long side (side 32) is divided into two. Therefore, the second slit 31 is obtained by fusing the step portion and the second step portion into one as will be described later. Further, the slit 30 and the second slit 31 form a T-shaped through hole on the −Z′-axis side of the piezoelectric vibrating piece 10.

  The region sandwiched between the slit 30 and the first side 14 becomes the mount portion 42, and the region sandwiched between the slit 30 and the second side 18 becomes the mount portion 44, and the extraction electrodes 52 and 54 are connected to the mount portions 42 and 44. As it is formed, a conductive adhesive 56 is applied. Therefore, the piezoelectric vibrating piece 10 is supported by the conductive adhesive 56 in a cantilevered state with the end portion 12 on the −Z ′ axis side as a fixed end and the end portion 22 on the + Z ′ axis side as a free end.

  Further, a thin portion 46 is formed at the approximate center of the piezoelectric vibrating piece 10. The thin portion 46 is formed by half etching from one main surface side of the piezoelectric vibrating piece 10 separately from the step of forming the outer shape of the piezoelectric vibrating piece 10. Since the periphery of the thin portion 46 is the same as the thickness of the outer shape of the piezoelectric vibrating piece 10, the strength of the piezoelectric vibrating piece 10 can be maintained.

  In more detail, the thin portion 46 is not constant in thickness, and has an inclined surface (not shown) inclined from the normal line of the main surface of the piezoelectric vibrating piece 10 at the periphery of the thin portion 40, and as it goes toward the periphery. It is formed to increase the thickness. Therefore, the excitation electrodes 48 and 50 are formed on the center portion of the thin portion 46 and parallel to the main surface of the piezoelectric vibrating piece 10, avoiding such an inclined surface (not shown).

  Similarly, due to the anisotropy of the quartz crystal, an end face 60 and 64 along the X-axis direction ends 58 and 62 of the piezoelectric vibrating piece 10 has a ridge 66 (described later) having a ridge line along the Z ′ axis. ) Is formed. Further, a peak portion 66 (see FIG. 2) is also formed on the end surface 31a extending in the Z′-axis direction of the second slit.

  On the other hand, valleys 68 (see FIG. 2) described later are formed on the first end surface 16 and the second end surface 20 of the end portion 12 in the −Z′-axis direction. Similarly, an end surface 32a having a long side (side 32) in the X-axis direction of the slit 30 and a trough portion 68 (see FIG. 2) also on the end surface 24 having the long side in the X-axis direction of the end portion 22 in the + Z′-axis direction. Is formed.

  In addition, excitation electrodes 48 and 50 and extraction electrodes 52 and 54 are formed on the piezoelectric vibrating piece 10. The excitation electrodes 48 and 50 are formed on both surfaces of the piezoelectric vibrating piece 10 so as to face each other at the center of the thin portion 46.

  The extraction electrode 52 is formed so as to be extracted from the excitation electrode 48 to the mount portion 42. The extraction electrode 54 is located at the end portion 62 in the X-axis direction of the piezoelectric vibrating piece 10 from the excitation electrode 50 to the mounting portion 44 on the same surface side as the extraction electrode 50 via the end face 64 having the long side of the piezoelectric vibrating piece 10. It is formed in the pulled-out manner. The excitation electrodes 48 and 50 and the extraction electrodes 52 and 54 are formed by depositing a metal film on the entire surface of the piezoelectric vibrating piece 10 and etching the metal film while leaving portions for forming the excitation electrodes 48 and 50 and the extraction electrodes 52 and 54. It is formed.

  The excitation electrodes 48 and 50 can generate a thickness shear vibration at a predetermined resonance frequency in the thin portion 46 by an AC voltage applied to the excitation electrodes 48 and 50.

  In the present embodiment, the path from the mount portions 42 and 44 where the extraction electrodes 52 and 54 are formed and fixed to the substrate 90 (see FIG. 1C) to the portion where the excitation electrodes 48 and 50 are formed is a slit. 30 is longer. As a result, the stress from the mount portions 42 and 44 to the portions where the excitation electrodes 48 and 50 are formed is relieved, and the piezoelectric vibrating piece 10 is obtained in which frequency fluctuations due to reflow and aging are suppressed.

  FIG. 3 is a schematic diagram showing the manufacturing process (outer shape forming process) of the piezoelectric vibrating piece, FIG. 4 is a schematic diagram of the manufacturing process (thin wall portion forming process) of the piezoelectric vibrating piece, and FIG. The schematic diagram of a process (electrode formation process) is shown. Next, the manufacturing process of the piezoelectric vibrating piece according to this embodiment will be described.

  As shown in FIG. 3, the outer shape of the piezoelectric vibrating piece is first formed. First, as shown in FIG. 3A, an AT-cut quartz substrate 74 is prepared as a piezoelectric element plate, and a resist film 76 is applied on the quartz substrate 74. As shown in FIG. 3B, the quartz substrate 74 has a rectangular outer shape with the Z′-axis direction as the long side and the X-axis direction as the short side, and a T-shaped through-hole (slit 30, second slit 31). The resist film 76 is exposed using a photomask 78 corresponding to the shape of), and the exposed resist film 76a is removed as shown in FIG. Then, as shown in FIG. 3D, etching is performed until the exposed portion of the quartz substrate 74 penetrates, and the resist film 76 is removed as shown in FIG. At this time, the end surface (end surface 60, end surface 64) having the end portions in the X-axis direction (end portion 58, end portion 62) as long sides respectively, and a crest portion 66 (see FIG. 2), and the end surface 32a having a long side (side 32) in the X-axis direction of the first end surface 16, the second end surface 20, and the slit 30 of the end portion 12 in the Z'-axis direction is formed in a trough described later. 68 (see FIG. 2) is formed.

  Next, as shown in FIG. 4, a thin portion 46 is formed. First, as shown in FIG. 4A, a resist film 80 is applied to a quartz substrate 74 on which the outer shape of the piezoelectric vibrating piece 10 is formed. 4B, the resist film 80 is exposed using a photomask 82 corresponding to the shape of the thin portion 46, and the exposed resist film 80a is removed as shown in FIG. 4C. Then, as shown in FIG. 4D, the portion where the quartz substrate 74 is exposed is half-etched, and the resist film 80 is removed as shown in FIG.

  As shown in FIG. 5, the excitation electrodes 48 and 50 and the extraction electrodes 52 and 54 are formed on the quartz substrate 74 having the outer shape finally formed. First, as shown in FIG. 5A, a metal film 84 of Cr, Au or the like is deposited on the entire surface of the quartz substrate 74 by sputtering or the like. At this time, the metal film 84 is also deposited on the end face of the quartz substrate 74. Then, as shown in FIG. 5B, a resist film 86 is applied to the entire surface of the quartz substrate 74 on which the metal film 84 is deposited. At this time, a resist film 86 is also applied to the end face of the quartz substrate 74. Next, as shown in FIG. 5C, the resist film 86 is exposed using a photomask 88 corresponding to the shapes of the excitation electrodes 48 and 50 and the extraction electrodes 52 and 54 on both surfaces of the piezoelectric vibrating piece 10. The light to be exposed at this time is irradiated on both surfaces from the normal direction of the quartz substrate 74, but light is applied to a valley portion 68 (see FIG. 2) described later formed on the first end surface 16, the second end surface 20, and the end surface 32a. Therefore, the resist film 86 applied to the valley 68 (see FIG. 2) is not exposed. Next, as shown in FIG. 5D, the exposed resist film 86a is removed, and as shown in FIG. 5E, the metal film 84 other than the portions corresponding to the excitation electrodes 48 and 50 and the extraction electrodes 52 and 54 is formed. Expose and etch. At this time, the metal film 84 deposited on the valleys 68 (see FIG. 2) formed on the first end surface 16, the second end surface 20, and the end surface 32a is not exposed and remains without being etched. Finally, as shown in FIG. 5 (f), the piezoelectric vibrating piece 10 is formed by removing the resist film 86.

  The piezoelectric vibrating reed 10 formed in this way has a metal film formed on the first end face 16, the second end face 20, and the end face 32a in addition to the metal film 84 related to the excitation electrodes 48 and 50 and the extraction electrodes 52 and 54. 84. The metal film 84 formed on the end surfaces (end surface 60, end surface 64) having the long sides of the X-axis direction ends (end portion 58, end portion 62) of the piezoelectric vibrating piece 10 is removed by etching.

  Using the above-described piezoelectric vibrating piece 10, the mount portions 42 and 44 on which the extraction electrodes 52 and 54 are formed are directed toward the substrate 90, and a conductive adhesive 56 is applied to the extraction electrodes 52 and 54 to thereby apply the piezoelectric vibrating piece 10. A piezoelectric vibrator is formed by bonding to the substrate 90. At this time, the conductive adhesive 56 extends to the first side 14 and the second side 18 on the Z′-axis side (−Z′-axis side) of the piezoelectric vibrating piece 10, and the first end surface having the first side 14 as a long side. 16 and may reach the second end face 20 having the second side 18 as a long side. Similarly, the conductive adhesive 56 may reach the end surface 32 a having the long side (side 32) in the X-axis direction of the slit 30.

  Accordingly, when the conductive adhesive 56 is applied to the mount portions 42 and 44, the mount and the conductive adhesive 56 applied to the mount portion 42 by the metal film 84 remaining in the valley 68 (see FIG. 2) described later. There is a possibility that the conductive adhesive 56 applied to the portion 44 is short-circuited.

  However, in the present embodiment, the valley portion 68 (see FIG. 2) formed on the first end surface 16 and the valley portion 68 (see FIG. 2) formed on the second end surface 20 are formed by the step portion (second slit 31). It is divided. Similarly, the valley 68 (see FIG. 2) formed on the end surface 32a is also divided by the second stepped portion (second slit 31). Furthermore, since the second slit 31 (stepped portion, second stepped portion) has an end surface 31a extending in the Z′-axis direction from which the metal film 84 has been removed, the metal film remaining in each valley portion 68 (see FIG. 2). 84 are insulated from each other. Therefore, when the conductive adhesive 56 is applied to the first end face 16 side (mount part 42) and the second end face 20 side (mount part 44) of the mount part, the conductive adhesives 56 are connected to the valley part 68 ( The yield at the time of mounting of the piezoelectric vibrating piece 10 can be increased without short-circuiting via (see FIG. 2).

  Note that when the conductive adhesive 56 is applied to the portions where the extraction electrodes 52 and 54 of the mount portions 42 and 44 are formed as in the present embodiment, the mount portions 42 and 44 are mechanically connected to the piezoelectric vibrating piece 10 and electrically connected. Connections are made simultaneously. Therefore, the mounting process can be simplified and the cost can be suppressed.

  6 and 7 show a modification of the step portion of the present embodiment. In the present embodiment, the step portion (second step portion) can be formed in other forms. For example, as shown in FIG. 6, the first side 15 and the second side 19 are shifted from each other in the Z′-axis direction, and the step portion is connected from the side 92 that connects the first side 15 and the second side 19 and extends in the Z′-axis direction. Can be formed. Similarly, a step portion can be formed on the side 32 in the X-axis direction of the slit by forming the side 93 in the Z′-axis direction.

  Further, as shown in FIG. 7, a stepped portion is formed by a convex portion 94 protruding in the −Z′-axis direction from the end portion 12 on the −Z′-axis side of the piezoelectric vibrating piece 10, and the slit 30 also has a side extending in the X-axis direction. The second stepped portion can be formed by the convex portion 96 protruding from 32 in the + Z′-axis direction. In any case, since the convex portions 94 and 96 have sides and end surfaces extending in the Z′-axis direction, a short circuit between the end surfaces divided by the convex portions 94 and 96 can be prevented. The convex portions 94 and 96 may be a triangle as shown in FIG. 2 instead of a rectangle, but it is necessary to form the apex angle to be an acute angle as will be described later. Moreover, it can form by the recessed part formed by notching the edge part 12 instead of a convex part, and the recessed part which notched the end surface 32a. And the above-mentioned 2nd slit 31 is formed by uniting these two recessed parts.

  8 and 9 show modifications of the thin portion of the present embodiment. 8A is a plan view, FIG. 8B is a bottom view, FIG. 8C is a cross-sectional view taken along line AA in FIG. 8A, and FIG. 8D is B in FIG. FIG. 9 (a) is a plan view, FIG. 9 (b) is a bottom view, FIG. 9 (c) is a cross-sectional view taken along line AA of FIG. 9 (a), and FIG. 9 (d) is FIG. 9 (a). It is a BB sectional view.

  As shown in FIG. 8, the thin portion 47 can be formed by wet etching up to the end portion 22 in the + Z′-axis direction. Since the end portion 22 in the + Z′-axis direction is a free end of the piezoelectric vibrating piece 10, this portion is reduced in weight, so that the shock resistance of the piezoelectric vibrating piece 10 after mounting can be improved. Furthermore, as shown in FIG. 9, the thin portion 47a can be formed by thinly etching the end portions 58 and 62 in the X-axis direction. Thereby, the impact resistance of the piezoelectric vibrating piece 10 after mounting can be further improved.

  FIG. 2 shows a simulation result of the end face shape of the quartz substrate, FIG. 2 (a) is a schematic diagram of the piezoelectric vibrating reed (part 1) used for the simulation and a cross-sectional shape taken along the line CC, and FIG. 2 (b) is used for the simulation. FIG. 2C is a schematic diagram of the piezoelectric vibrating reed (part 2) used for the simulation, and FIG. 2C is a cross-sectional view taken along the line E-E.

  The inventor of the present application performed a simulation of the end face shape of the quartz substrate. As shown in FIGS. 2A and 2B, the piezoelectric vibrating piece (part 1) used for the simulation is a rectangular inverted mesa type having a long side in the Z′-axis direction and a short side in the X-axis direction. The piezoelectric vibrating piece includes mount parts 42 and 44, a slit 30, and a thin part 46 arranged in this order in the Z′-axis direction. That is, it is a structure which does not have the level | step-difference part in this embodiment, and a 2nd level | step difference part. Then, a simulation of the end face shape of the piezoelectric vibrating piece in the cross section taken along the line CC shown in FIG. 2A and the cross section taken along the line DD shown in FIG. Then, as shown in FIG. 2A, in the end surfaces 60 and 64 having the end portions 58 and 62 in the X-axis direction as long sides, the central portion in the thickness direction rises compared to both ends in the thickness direction, and the Z ′ axis It can be seen that a crest 66 having a ridge line in the direction is formed. Similarly, a crest 66 is formed on the end face 36 of the side 34 extending in the Z′-axis direction of the slit 30. Accordingly, it can be seen that the peak portion 66 is also formed on the end surface 31 a of the second slit 31. The light that sensitizes the resist film reaches the slope of the peak portion 66 and there is no shadow portion, so the metal film formed on the slope of the peak portion 66 can be removed.

  On the other hand, as shown in FIG. 2B, the end surface 17 having the end portion 12 in the Z-axis direction as a long side is etched so that the central portion in the thickness direction is cut compared to both ends in the thickness direction. 17, it can be seen that a valley 68 is formed. In the present embodiment, the valley portion 68 is generated on the first end surface 16 and the second end surface 20 of the end portion 12 and the end surface 32 a having the long side (side 32) in the X-axis direction of the slit 30. As described above, the light used for the exposure of the resist film is irradiated on both surfaces from the normal direction of the piezoelectric vibrating piece 10, so that the light does not reach the valley portion 68 and becomes a shadow. Therefore, it can be seen that the metal film deposited on this portion cannot be removed because the resist film formed on the metal film is not exposed.

  On the other hand, as shown in FIG. 2C, the present inventor further provided a triangular convex portion 70 (second stepped portion) having an apex angle of 90 degrees in the slit 30 of the piezoelectric vibrating piece (part 1). In this case, the shape of the end face of the piezoelectric vibrating piece (part 2) in the cross section taken along the line EE was simulated. In this case, the side forming the convex portion 70 is inclined by 45 degrees with respect to the Z ′ axis, but as shown in FIG. 2C, the end surface that is slightly in contact with the side forming the convex portion 70 is A valley portion 72 is formed. However, it is considered that by reducing this angle (making it an acute angle), this end face shape approaches the cross-sectional shape shown in FIG.

10 ......... Piezoelectric vibrating piece, 12 ......... End, 14 ......... First side, 15 ......... First side, 16 ......... First end surface, 18 ......... Second side, 19 ... ... second side, 20 ......... second end face, 22 ......... end, 24 ......... end face, 30 ......... slit, 31 ......... second slit, 31a ......... end face, 32 ... ... side, 32a ... end face, 34 ......... side, 36 ... end face, 42 ... mount part, 44 ... mount part, 46 ... thin part, 47 ... thin part, 47a ......... Thin portion, 48 ......... Excitation electrode, 50 ......... Excitation electrode, 52 ......... Extraction electrode, 54 ......... Extraction electrode, 56 ......... Conductive adhesive, 58 ......... End, 60 ......... End face, 62 ......... End face, 64 ......... End face, 66 ......... Mountain, 68 ......... Valley, 70 ......... Convex, 72 ......... Valley, 74 ... ... Quartz substrate, 76 ... ... Resist film, 76a ......... Resist film, 78 ...... Photo mask, 80 ......... Resist film, 80a ......... Resist film, 82 ...... Photo mask, 84 ...... Metal film, 86 ...... Resist film, 86a... Resist film, 88... Photomask, 90... Substrate, 92... Side, 93... Side, 94.

Claims (8)

A piezoelectric vibrating piece obtained by wet-etching an AT-cut piezoelectric base plate,
A slit having a long side in the X-axis direction in the piezoelectric vibrating piece;
A mount portion disposed between the slit and the end portion on the Z′-axis side of the piezoelectric vibrating piece,
The end portion includes a first end surface and a second end surface extending in the X-axis direction, and a stepped portion,
The step portion is
A piezoelectric vibrating piece, which is disposed between the first end surface and the second end surface and has a step in the Z′-axis direction.   2. The piezoelectric vibrating piece according to claim 1, wherein a second step portion having a long side in the Z-axis direction is disposed on an end surface having a long side in the X-axis direction of the slit.   3. The piezoelectric vibrating piece according to claim 1, wherein the stepped portion is a convex portion protruding in the Z′-axis direction from the end portion, or a concave portion in which a part of the end portion is cut out. A pair of extraction electrodes provided on the first end surface side and the second end surface side of the mount portion, respectively, connected to excitation electrodes formed on the piezoelectric vibrating piece;
4. The device according to claim 1, wherein one of the pair of extraction electrodes is routed to an opposite surface so that the pair of extraction electrodes are arranged on the same surface of the piezoelectric vibrating piece. The piezoelectric vibrating piece according to item 1. The piezoelectric vibrating piece has a thin portion that has been wet etched into a thin wall, and the thin portion and the mount portion are disposed so as to sandwich the slit,
The piezoelectric vibrating piece according to claim 1, wherein the excitation electrode is disposed in the thin portion.   6. The piezoelectric vibrating piece according to claim 5, wherein the thin-walled portion has a shape that is wet-etched into a thin-walled portion up to the opposite end portion of the mount portion.   The piezoelectric vibrating piece according to claim 6, wherein the thin-walled portion has a shape obtained by performing wet etching processing to a thin wall up to an end portion in the X-axis direction of the piezoelectric vibrating piece.   The surface on which the pair of extraction electrodes of the piezoelectric vibrating piece according to any one of claims 3 to 7 is disposed is directed to a substrate side, and the pair of extraction electrodes and the substrate are interposed via a conductive adhesive. A piezoelectric vibrator characterized by being connected.

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