JP6590482B2 - Crystal oscillator - Google Patents

Description

  The present invention relates to a crystal resonator element used in an electronic device or the like.

  In an electronic device such as a computer, a mobile phone, or a small information device, a crystal resonator or a crystal oscillator is mounted as one of electronic components. This crystal resonator or crystal oscillator is used as a reference signal source or a clock signal source. In addition, a crystal resonator element is included inside the crystal resonator and the crystal oscillator. As an example of the crystal resonator element, a tuning fork-type bent crystal resonator element (hereinafter abbreviated as “vibrator element”) is taken up.

  FIG. 5 is a plan view showing the entire vibration element of the related art 1. Hereinafter, description will be given based on this drawing.

  The vibration element 80 of the related technique 1 includes a base 81 and two vibration arm portions 82 a and 82 b extending from the base 81 in one direction (extension direction 801). The vibrating arm portions 82a and 82b are provided with groove portions 85a and 85b, respectively. The base 81 and the vibrating arm portions 82 a and 82 b are made of a crystal piece 86. In addition to the crystal piece 86, the vibration element 80 includes pad electrodes 91a and 91b, excitation electrodes 92a and 92b, frequency adjusting metal films 93a and 93b, wiring patterns 94a and 94b, and the like.

  Next, an example of a method for manufacturing the vibration element 80 will be briefly described.

  First, for example, a corrosion resistant film is formed on the front and back of a quartz wafer having a thickness of about 100 μm by sputtering. Subsequently, a photosensitive resist is formed on the corrosion-resistant film on the front and back of the quartz wafer, and the photosensitive resist is patterned (exposed, developed, and dried) so that a tuning-fork-shaped corrosion-resistant film remains on both the front and back surfaces. The corrosion-resistant film is removed by etching. Subsequently, after removing the photosensitive resist, the photosensitive resist is patterned again on the front and back corrosion-resistant films in order to determine the shape of the electrode.

  Subsequently, the exposed crystal portion is removed by wet etching. At this time, the outer shape of the crystal piece 86 and the grooves 85a and 85b are formed simultaneously. That is, the base 81, the vibrating arm portions 82a and 82b, and the groove portions 85a and 85b are formed with the photosensitive resist remaining. Subsequently, the corrosion-resistant film exposed on the front and back surfaces of the crystal piece 86 is removed by etching. Thereby, a crystal surface is obtained.

  Subsequently, an electrode film is formed by sputtering on the entire surface of the crystal piece 86 with the photosensitive resist remaining. Subsequently, the photosensitive resist formed on the front and back surfaces of the crystal piece 86 is peeled off, and the electrode film formed thereon is also peeled off. This is realized by immersing these in a solution for dissolving the photosensitive resist. Finally, the corrosion-resistant film remaining under the photosensitive resist is removed by etching. Thus, an electrode is formed on the crystal piece 86 by the lift-off method.

  Note that X, Y ′, and Z ′ in FIG. 5 are crystal axes of the crystal piece 86. In the X-axis, Y-axis, and Z-axis, which are crystal axes of quartz, the Y-axis and Z-axis after rotation when rotated within a range of ± 5 degrees around the X-axis are defined as Y'-axis and Z'-axis, respectively. Yes. At this time, the longitudinal direction, that is, the extending direction 801 of the vibrating arm portions 82a and 82b is the Y′-axis direction, the thickness direction of the crystal piece 86 is the Z′-axis direction, and the direction in which the vibrating arm portions 82a and 82b are arranged (short) (Hand direction) is the X-axis direction.

JP 2011-151568 A

  However, the vibration element 80 of Related Art 1 has the following problems. FIG. 6 is an enlarged plan view showing the vicinity of the root of the vibrating arm portion in the related technique 1. Hereinafter, a description will be given based on FIGS. 5 and 6.

  In the process of forming the crystal piece 86 by wet etching, an etching residue is generated due to the crystal axis anisotropy of the etching rate (see, for example, Patent Document 1). In particular, as shown in FIG. 6, in the vicinity of the root of the vibrating arm portion 82a, a large triangular residue centering on the contact point between the −X surface 82-x inside the vibrating arm portion 82a and the Y ′ surface 81y of the base portion 81. 871 is generated, and a triangular residue 872 smaller than the residue 871 is generated around the contact point between the + X surface 82 + x outside the vibrating arm portion 82a and the Y ′ surface 81y of the base 81. Similarly, a large triangular residue 871 is generated in the vicinity of the root of the vibrating arm portion 82b around the contact point between the -X surface 82-x outside the vibrating arm portion 82b and the Y 'surface 81y of the base portion 81. A triangular residue 872 smaller than the residue 871 is generated around the contact point between the + X surface 82 + x inside the arm portion 82 b and the Y ′ surface 81 y of the base portion 81.

  Therefore, due to the presence of the residual residues 871 and 872 of the vibrating arm portions 82a and 82b, the actual dimensions of the vibrating arm portions 82a and 82b become shorter and thicker than the design values, and each of the vibrating arm portions 82a and 82b. Symmetry is reduced. As a result, the frequency characteristics and CI (Crystal Impedance) value of the vibration element 80 are deteriorated.

  Accordingly, an object of the present invention is to provide a resonator element that can improve the frequency characteristics and the CI value by suppressing the generation of etching residue at the base of the vibrating arm portion.

The vibration element according to the present invention is
The base,
First and second vibrating arms extending in one direction from the base;
The two outer to each other of said first and second both inside one another of the first and second oscillation arm in the base of the oscillation arm and the first and second vibrating arm portion in the base portion The cuts provided,
A quartz crystal resonator element comprising:
The base portion and the vibrating arm portion are composed of a single crystal piece,
In the X-axis, Y-axis, and Z-axis that are crystal axes of the crystal piece, the Y-axis and Z-axis after rotation when rotated within a range of ± 5 degrees around the X-axis are respectively Y'-axis and Z ' The axis,
Of the planes orthogonal to the X axis, the plane facing the + X axis direction is the + X plane, of the planes orthogonal to the X axis, the plane facing the −X axis direction is the −X plane, and the plane orthogonal to the Y ′ axis is Y 'When faced,
The vibration extending direction of the arm portion is the Y 'axis direction, the first and second oscillation arm of each other inside said first oscillation arm of the inner said - X plane and the second The inner side of the vibrating arm portion is the + X plane, and the outer sides of the first and second vibrating arm portions are the outer side of the first vibrating arm portion is the + X plane and the second vibrating arm portion. The outer surface of the base is the -X plane, and the surface of the base portion in contact with the inner side and the outer side of the first and second vibrating arm portions is the Y 'plane,
The notch inside the first vibrating arm is provided on the same plane as the -X plane inside the first vibrating arm,
The notch inside the second vibrating arm is provided on the same plane as the + X plane inside the second vibrating arm,
The notch on the outer side of the first vibrating arm is provided on the same plane as the + X plane on the outer side of the first vibrating arm;
The notch on the outer side of the second vibrating arm is provided on the same plane as the -X plane on the outer side of the second vibrating arm;
Etching residue generated in the cut is hidden in the cut.
It is characterized by that.

  According to the present invention, by providing a notch in the base of the vibrating arm portion in the base portion, it is possible to suppress the generation of etching residue at the root of the vibrating arm portion, so that the frequency characteristics and CI value of the vibrating element can be improved.

FIG. 3 is a plan view illustrating the entire vibration element according to the first embodiment. 2A is a cross-sectional view taken along line II-II in FIG. FIG. 2B is a schematic cross-sectional view illustrating a state in which the vibration element of Embodiment 1 is mounted on an element mounting member and the element mounting member is vacuum-sealed with a lid member. FIG. 3B is an enlarged plan view showing the vicinity of the root of the vibrating arm in the first embodiment. FIG. 3A shows a case where no cut is provided, FIG. 3B shows a case where a short cut is provided, and FIG. Is a case where a long cut is provided. FIG. 6 is a plan view illustrating an entire vibration element according to a second embodiment. It is a top view which shows the whole vibration element of the related technology 1. 10 is an enlarged plan view showing the vicinity of the root of a vibrating arm portion in Related Art 1. FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described with reference to the accompanying drawings. In the present specification and drawings, the same reference numerals are used for substantially the same components. The shapes depicted in the drawings are drawn so as to be easily understood by those skilled in the art, and thus do not necessarily match the actual dimensions and ratios.

  FIG. 1 is a plan view illustrating the entire vibration element according to the first embodiment. 2A is a cross-sectional view taken along line II-II in FIG. FIG. 2B is a schematic cross-sectional view illustrating a state in which the vibration element of Embodiment 1 is mounted on an element mounting member and the element mounting member is vacuum-sealed with a lid member. Hereinafter, description will be given based on these drawings.

  The vibration element 10 according to the first embodiment includes a base portion 11, two vibration arm portions 12 a and 12 b extending from the base portion 11 in one direction (extension direction 101), and vibration arm portions 12 a and 12 b in the base portion 11. And notches 13a and 13b provided at the base of the. The notches 13a and 13b are provided in at least one (both in the first embodiment) inside the vibrating arm portions 12a and 12b at the root of the vibrating arm portions 12a and 12b. Note that the inside of the vibrating arm portions 12a and 12b refers to the side facing each other, and the outside of the vibrating arm portions 12a and 12b refers to the opposite side of the inside.

  The base portion 11 and the vibrating arm portions 12 a and 12 b are formed of a single crystal piece 16. In the X axis, Y axis, and Z axis, which are crystal axes of the crystal piece 16, the Y axis and Z axis after rotation when rotated within a range of ± 5 degrees around the X axis are respectively Y ′ axis and Z ′. Axis. At this time, the extending direction 101 is the Y′-axis direction. The notch 13a is provided in the Y ′ surface 11y of the base 11 in contact with the −X surface 12-x of the vibrating arm portion 12a. The notch 13b is provided in the Y ′ surface 11y of the base portion 11 in contact with the + X surface 12 + x of the vibrating arm portion 12b.

  The vibrating arms 12a and 12b are provided with grooves 15a and 15b, respectively. In addition to the crystal piece 16, the vibration element 10 includes pad electrodes 21a and 21b, excitation electrodes 22a and 22b, frequency adjusting metal films 23a and 23b, wiring patterns 24a and 24b, and the like. The manufacturing method of the vibration element 10 is the same as the manufacturing method of the vibration element of the related art 1 except that the portions to be cut 13a and 13b are added to the photomask for forming the corrosion resistant film. The back surface of the vibration element 10 has the same configuration as that in FIG.

  Next, the configuration of the vibration element 10 will be described in more detail.

  The base 11 is a flat plate having a substantially rectangular shape in plan view. The crystal piece 16 has a tuning fork shape in which the base portion 11 and the vibrating arm portions 12a and 12b are integrated, and is manufactured by a film forming technique, a photolithography technique, and a wet etching technique.

  Groove portions 15a and 15b may be provided in the length direction of the vibrating arm portions 12a and 12b, respectively. The groove portions 15a and 15b are, for example, two on the front and back surfaces of the vibrating arm portion 12a and two on the front and back surfaces of the vibrating arm portion 12b, from the boundary portion with the base 11 to the tip of the vibrating arm portions 12a and 12b. Thus, the vibrating arms 12a and 12b are provided with a predetermined length in parallel with the length direction. In the first embodiment, two grooves 15a and 15b are provided on the front and back surfaces of the vibrating arm 12a and two grooves on the front and back surfaces of the vibrating arm 12b. However, the number of the grooves 15a and 15b is not limited. For example, one may be provided on the front and back surfaces of the vibrating arm portion 12a and one on each of the front and back surfaces of the vibrating arm portion 12b, or may be provided on only one side of the front and back surfaces.

  Excitation electrodes 22a are provided on both side surfaces of the vibrating arm 12a so that the planes facing each other across the crystal have the same polarity, and excitation is provided inside the groove 15a on the front and back surfaces and between the two grooves 15a. An electrode 22b is provided. Similarly, the vibrating arm portion 12b is provided with excitation electrodes 22b on both side surfaces so that the planes facing each other across the crystal have the same polarity, and inside the groove portion 15b on the front and back surfaces and on the two groove portions 15b. An excitation electrode 22a is provided between them. Therefore, in the vibrating arm portion 12a, the excitation electrode 22a provided on both sides and the excitation electrode 22b provided in the groove 15a have different polarities, and in the vibrating arm portion 12b, the excitation electrode 22b provided on both sides. And the excitation electrode 22a provided in the groove 15b have different polarities.

  The base 11 is provided with pad electrodes 21a and 21b and wiring patterns 24a and 24b that electrically connect the pad electrodes 21a and 21b and the excitation electrodes 22a and 22b. The pad electrode 21a, the excitation electrode 22a, the frequency adjusting metal film 23a, and the wiring pattern 24a are electrically connected to each other. The pad electrode 21b, the excitation electrode 22b, the frequency adjusting metal film 23b, and the wiring pattern 24b are also electrically connected to each other.

  The pad electrodes 21a and 21b, the excitation electrodes 22a and 22b, the frequency adjusting metal films 23a and 23b, and the wiring patterns 24a and 24b are formed from the same metal film, for example, by a lift-off method, for example, a Pd or Au layer on the Ti layer. Has a laminated structure.

  As shown in FIG. 2B, the vibration element 10 is fixed to the pad electrode 43 on the element mounting member 42 side and electrically connected via the pad electrodes 21a and 21b. The The crystal resonator 40 is obtained by vacuum-sealing the element mounting member 42 with the lid member 44. Although not shown, the element mounting member 42 is provided with an external connection terminal that conducts to the pad electrode 43.

  Next, the operation of the vibration element 10 will be described.

  When the tuning fork type vibration element 10 is vibrated, an alternating voltage is applied to the pad electrodes 21a and 21b. When an electrical state after application is instantaneously captured, the excitation electrodes 22b provided in the groove portions 15a on the front and back of the vibrating arm portion 12a have a positive potential, and the excitation electrodes 22a provided on both side surfaces of the vibrating arm portion 12a are A negative electric potential is generated, and an electric field is generated from positive to negative. At this time, the excitation electrodes 22a provided in the groove portions 15b on the front and back of the vibrating arm portion 12b have a negative potential, and the excitation electrodes 22b provided on both side surfaces of the vibrating arm portion 12b have a positive potential, and are generated in the vibrating arm portion 12a. The polarity is opposite to the polarity, and an electric field is generated from plus to minus. The electric field generated by the alternating voltage causes a stretching phenomenon in the vibrating arm portions 12a and 12b, and a flexural vibration mode having a predetermined resonance frequency is obtained.

  Next, the action and effect when the vibration element 10 of the first embodiment is compared with the related technique 1 will be described. FIG. 3 is an enlarged plan view showing the vicinity of the root of the vibrating arm portion in the first embodiment. FIG. 3A shows a case where no cut is provided, and FIG. 3B shows a case where a short cut is provided. 3 [C] is a case where a long cut is provided. Hereinafter, description will be given with reference to FIGS.

  In FIG. 3, the vicinity of the root inside the vibrating arm portion 12 a is shown in an enlarged manner. FIG. 3A shows a case where the cut 13a is not provided. In this case, a triangular etching residue 171 is generated around the contact point between the −X surface 12 -x of the vibrating arm portion 12 a and the Y ′ surface 11 y of the base portion 11. At this time, the length of the residue 171 in the Y′-axis direction is L.

  FIG. 3B shows a case where a cut 13a having a length L / 2 is provided. In this case, a residue 171 having a length L / 2 is generated. FIG. 3C shows the case where a cut 13a having a length L is provided. In this case, the residue 171 is hidden in the cut 13a. Therefore, in order to suppress the generation of the residue 171, the length of the cut 13 a in the Y′-axis direction is set so that the residue 171 generated on the −X plane 12 -x of the vibrating arm portion 12 a when the cut 13 a is not provided. The length is preferably longer than the length L in the Y′-axis direction.

  For example, the length L of the cut 13a is about 10 to 60 μm, and the width W is about 5 to 30 μm. Moreover, since the cut 13a only needs to suppress etching residues, it is not necessary to penetrate in the thickness direction. Here, the vicinity of the root inside the vibrating arm portion 12a has been described, but the same can be said for the vicinity of the root inside the vibrating arm portion 12b.

  As described above, according to the first embodiment, by providing the notches 13a and 13b at the roots of the vibrating arm portions 12a and 12b in the base 11, the generation of etching residues at the roots of the vibrating arm portions 12a and 12b is suppressed. Therefore, the frequency characteristics and CI value of the vibration element 10 can be improved.

  Further, in the root of the vibrating arm portions 12a and 12b, when the notches 13a and 13b are provided on both inner sides of the vibrating arm portions 12a and 12b, the symmetry between the vibrating arm portion 12a and the vibrating arm portion 12b is improved. It is more effective. Although the cuts 13a and 13b are effective in either one, the residue on the contact side between the −X surface 12-x of the vibrating arm 12a and the Y ′ surface 11y of the base 11 is + X of the vibrating arm 12b. Since it is larger than the residue on the contact side between the surface 12 + x and the Y ′ surface 11y of the base 11, the cut 13a is provided on the Y ′ surface 11y of the base 11 in contact with the −X surface 12-x of the vibrating arm 12a. preferable.

  Next, the resonator element according to the second embodiment will be described. FIG. 4 is a plan view illustrating the entire vibration element according to the second embodiment. Hereinafter, description will be given based on this drawing.

  The vibration element 50 according to the second embodiment includes a base portion 11, two vibrating arm portions 12 a and 12 b extending from the base portion 11 in one direction (extending direction 101), and vibrating arm portions 12 a and 12 b in the base portion 11. Incisions 13a, 13b, 53a, 53b provided at the base of the. The notches 13a and 13b are provided in at least one (both in the second embodiment) inside the vibrating arm portions 12a and 12b at the root of the vibrating arm portions 12a and 12b. The notches 53a and 53b are provided on at least one of the outer sides of the vibrating arm portions 12a and 12b (both in the second embodiment) at the root of the vibrating arm portions 12a and 12b. As a result, the symmetry of the two vibrating arm portions 12a and 12b is improved, so that the frequency characteristics and CI value of the vibrating element 50 can be further improved.

  According to the second embodiment, by providing the cuts 13a, 13b, 53a, and 53b at the roots of the vibrating arm portions 12a and 12b in the base portion 11, the inner sides of the vibrating arm portions 12a and the roots of the vibrating arm portions 12a and 12b and The generation of etching residues on the outside and on the inside and outside of the vibrating arm portion 12b can be suppressed. Therefore, since the symmetry of each of the vibrating arm portions 12a and 12b can be improved, the frequency characteristics and CI value of the vibrating element 50 can be further improved. In addition, although the cuts 53a and 53b are effective in either one, the residue on the contact side between the −X surface 12-x of the vibrating arm portion 12b and the Y ′ surface 11y of the base portion 11 is more vibrated in the vibrating arm portion 12a. Since it is larger than the residue on the contact side between the + X surface 12 + x and the Y ′ surface 11y of the base 11, it is preferable to provide the cut 53b.

  Other configurations, operations, and effects of the second embodiment are the same as those of the first embodiment.

  Although the present invention has been described with reference to the above embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention. Further, the present invention includes a combination of some or all of the configurations of the above-described embodiments as appropriate.

<Embodiment 1>
10 Vibration element 101 Extension direction (one direction)
11 base portion 11y Y 'surface 12a, 12b vibrating arm portion 12 + x + X surface 12-x-X surface 13a, 13b notch 15a, 15b groove portion 16 crystal piece 171 residue 21a, 21b pad electrode 22a, 22b excitation electrode 23a, 23b frequency Metal film for adjustment 24a, 24b Wiring pattern 40 Crystal resonator 41 Conductive adhesive 42 Element mounting member 43 Pad electrode 44 Lid member <Embodiment 2>
50 Vibration element 53a, 53b Notch <Related technology 1>
80 vibration element 801 extending direction 81 base 81y Y 'surface 82a, 82b vibration arm 82 + x + X surface 82-x-X surface 85a, 85b groove 86 crystal piece 871, 872 residue 91a, 91b pad electrode 92a, 92b excitation Electrode 93a, 93b Metal film for frequency adjustment 94a, 94b Wiring pattern

Claims (2)

The base,
First and second vibrating arms extending in one direction from the base;
The two outer to each other of said first and second both inside one another of the first and second oscillation arm in the base of the oscillation arm and the first and second vibrating arm portion in the base portion The cuts provided,
A quartz crystal resonator element comprising:
The base portion and the vibrating arm portion are composed of a single crystal piece,
In the X-axis, Y-axis, and Z-axis that are crystal axes of the crystal piece, the Y-axis and Z-axis after rotation when rotated within a range of ± 5 degrees around the X-axis are respectively Y'-axis and Z ' The axis,
Of the planes orthogonal to the X axis, the plane facing the + X axis direction is the + X plane, of the planes orthogonal to the X axis, the plane facing the −X axis direction is the −X plane, and the plane orthogonal to the Y ′ axis is Y 'When faced,
The vibration extending direction of the arm portion is the Y 'axis direction, the first and second oscillation arm of each other inside said first oscillation arm of the inner said - X plane and the second The inner side of the vibrating arm portion is the + X plane, and the outer sides of the first and second vibrating arm portions are the outer side of the first vibrating arm portion is the + X plane and the second vibrating arm portion. The outer surface of the base is the -X plane, and the surface of the base portion in contact with the inner side and the outer side of the first and second vibrating arm portions is the Y 'plane,
The notch inside the first vibrating arm is provided on the same plane as the -X plane inside the first vibrating arm,
The notch inside the second vibrating arm is provided on the same plane as the + X plane inside the second vibrating arm,
The notch on the outer side of the first vibrating arm is provided on the same plane as the + X plane on the outer side of the first vibrating arm;
The notch on the outer side of the second vibrating arm is provided on the same plane as the -X plane on the outer side of the second vibrating arm;
Etching residue generated in the cut is hidden in the cut.
A crystal resonator element characterized by the above. The length of the cut along the Y′-axis direction is longer than the length of the etching residue generated on the −X plane of the vibrating arm portion along the Y′-axis direction when the cut is not provided. ,
The crystal resonator element according to claim 1.

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