JP6842682B2 - Crystal oscillator and its manufacturing method - Google Patents

Description

The present invention relates to a crystal vibrating element and a method for manufacturing the same.

The piezoelectric vibrator is mounted on a mobile communication device or the like, and is used as, for example, a timing device or a load sensor. In particular, a crystal oscillator, which is a type of piezoelectric oscillator, uses artificial quartz as a piezoelectric material and has high frequency accuracy. The crystal vibrating element mounted on the crystal oscillator is formed by, for example, etching using a photolithography technique to perform outer shape processing on the crystal piece and patterning various electrodes on the crystal piece. Various configurations are being studied in order to improve the processing accuracy by etching.

For example, Patent Document 1 describes a step of etching a crystal piece using a photoresist and a corrosion-resistant film as a mask to provide a stepped surface or an inclined surface, a step of removing the photoresist and the corrosion-resistant film, and a metal film using the photoresist as a mask. A method of manufacturing a crystal vibrating element including a step of etching an excitation electrode, an extraction electrode, and the like to form an excitation electrode, an extraction electrode, and the like are disclosed.

Japanese Unexamined Patent Publication No. 2010-283660

However, when a stepped surface or an inclined surface is formed on a crystal piece to form an outer shape in which irregularities are formed on the main surface of the crystal piece, if a photoresist is formed after the outer shape is formed, the crystal is formed by surface tension or the like. The thickness of the photoresist decreases at the corners of the main surface of one piece. Due to such fluctuations in the thickness of the photoresist, there is a problem that, for example, the processing accuracy of the excitation electrode is lowered.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a crystal vibration element capable of reducing a manufacturing error of vibration characteristics and a method for manufacturing the same.

The method for manufacturing a crystal vibrating element according to one aspect of the present invention has a first main surface and a second main surface facing the first main surface, and is located on the central side when the first main surface is viewed in a plan view. A step of preparing a crystal piece having a central portion and a peripheral portion located outside the central portion, a step of providing a first excitation electrode in the central portion of the first main surface of the crystal piece, and a step of protecting the central portion. A step of removing a part of the peripheral edge portion while using the first excitation electrode as the metal mask to form a first side surface between the central portion and the peripheral edge portion on the first main surface side of the crystal piece, and as a metal mask. This includes a step of providing a first extraction electrode extending to the peripheral edge on the first main surface side of the crystal piece so as to come into contact with the first excitation electrode used.

The crystal vibrating element according to another aspect of the present invention has a first main surface and a second main surface facing the first main surface, and is located at the center when the first main surface is viewed in a plan view. It has a portion and a peripheral portion located outside the central portion, and a first side surface is formed between the central portion and the peripheral portion on at least the first main surface side of the first main surface and the second main surface. , The crystal piece, the first excitation electrode provided in the center of the first main surface of the crystal piece, and the second main surface of the crystal piece, provided in the center and facing the first excitation electrode. A second excitation electrode, a first extraction electrode electrically connected to the first excitation electrode, and a second extraction electrode electrically connected to the second excitation electrode are provided, and at least the first extraction electrode is provided. When the first main surface of the crystal piece is viewed in plan view, it covers at least a part of the first excitation electrode and extends from the central portion to the peripheral portion.

According to the present invention, it is possible to provide a crystal vibrating element capable of reducing a manufacturing error of vibration characteristics and a manufacturing method thereof.

FIG. 1 is an exploded perspective view schematically showing the configuration of the crystal oscillator according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the configuration of the cross section of the crystal oscillator shown in FIG. 1 along the line II-II. FIG. 3 is a cross-sectional view schematically showing the configuration of the crystal vibrating element shown in FIG. FIG. 4 is a flowchart schematically showing a part of the manufacturing method of the crystal vibrating element according to the first embodiment. FIG. 5 is a flowchart schematically showing the manufacturing method of the crystal vibrating element according to the first embodiment, following the flowchart shown in FIG. FIG. 6 is a cross-sectional view schematically showing a step of etching a crystal piece. FIG. 7 is a cross-sectional view schematically showing a step of providing the second adhesion layer and the second conductive layer. FIG. 8 is a cross-sectional view schematically showing a step of patterning a photoresist. FIG. 9 is a cross-sectional view schematically showing a step of etching the second adhesive layer and the second conductive layer. FIG. 10 is a cross-sectional view schematically showing a step of scraping the electrode surface in the central portion. FIG. 11 is a cross-sectional view schematically showing the configuration of the crystal oscillator according to the second embodiment. FIG. 12 is an exploded perspective view schematically showing the configuration of the crystal oscillator according to the third embodiment. FIG. 13 is a cross-sectional view schematically showing the configuration of the crystal oscillator according to the third embodiment. FIG. 14 is a perspective view schematically showing the configuration of the crystal vibration element according to the fourth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in the second and subsequent embodiments, the components that are the same as or similar to those of the first embodiment are represented by the same or similar reference numerals as those of the first embodiment, and detailed description thereof will be omitted as appropriate. Further, regarding the effects obtained in the second and subsequent embodiments, the same as those in the first embodiment will be omitted as appropriate. The drawings of each embodiment are examples, and the dimensions and shapes of each part are schematic, and the technical scope of the present invention should not be limited to the embodiment.

<First Embodiment>
First, the configuration of the crystal oscillator 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is an exploded perspective view schematically showing the configuration of the crystal oscillator according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the configuration of the cross section of the crystal oscillator shown in FIG. 1 along the line II-II. FIG. 3 is a cross-sectional view schematically showing the configuration of the crystal vibrating element shown in FIG. The first direction D1, the second direction D2, and the third direction D3 shown in the drawing are directions orthogonal to each other. The first direction D1, the second direction D2, and the third direction D3 may intersect each other at an angle other than 90 °. Further, the first direction D1, the second direction D2, and the third direction D3 are not limited to the direction of the arrow shown in FIG. 1 (positive direction), and include the direction opposite to the arrow (negative direction).

The Quartz Crystal Resonator Unit 1 is a type of piezoelectric oscillator (Piezoelectric Resonator Unit), and excites the Quartz Crystal Resonator 10 according to the applied voltage. The crystal vibrating element 10 uses a crystal piece (Quartz Crystal Element) 11 as a piezoelectric body that vibrates in response to an applied voltage.

As shown in FIG. 1, the crystal oscillator 1 includes a crystal vibrating element 10, a lid member 20, a base member 30, and a joining member 40. The base member 30 and the lid member 20 are cages for accommodating the crystal vibrating element 10. In the example shown here, the lid member 20 has a concave shape, specifically, a box shape having an opening, and the base member 30 has a flat plate shape. The shapes of the lid member 20 and the base member 30 are not limited to the above. For example, the base member may have a concave shape, and both the lid member and the base member have an opening on the side facing each other. It may be.

The crystal vibrating element 10 has a flaky crystal piece 11. The crystal piece 11 has a first main surface 11a and a second main surface 11b facing each other. The first main surface 11a is located on the side opposite to the side facing the base member 30, and the second main surface 11b is located on the side facing the base member 30.

The crystal piece 11 is, for example, an AT-cut type crystal piece. The main surface of the AT-cut type crystal piece is a surface parallel to the surface specified by the X-axis and the Z'axis (hereinafter, referred to as "XZ'plane". With respect to a surface specified by another axis or another direction. The same applies to.). Therefore, the first main surface 11a and the second main surface 11b of the crystal piece 11 correspond to the XZ'plane, respectively. The AT-cut type crystal piece is formed, for example, by etching a crystal substrate obtained by cutting and polishing a crystal-grown artificial quartz (Synthetic Quartz Crystal). The X-axis, Y-axis, and Z-axis are crystallographic axes of quartz, and the X-axis corresponds to the electric axis, the Y-axis corresponds to the mechanical axis, and the Z-axis corresponds to the optical axis. The Y'axis and the Z'axis are axes obtained by rotating the Y axis and the Z axis around the X axis in the direction of the Y axis to the Z axis by 35 degrees 15 minutes ± 1 minute 30 seconds, respectively. A different cut (for example, BT cut) other than the AT cut may be applied to the cut angle of the crystal piece.

The AT-cut type crystal piece 11 is parallel to the long side direction in which the long side parallel to the X-axis direction extends, the short side direction in which the short side parallel to the Z'axis direction extends, and the Y'axis direction. Has a thickness direction in which the thickness extends. The crystal piece 11 has a rectangular shape when the first main surface 11a is viewed in a plan view, and has a central portion 17 located in the center and contributing to excitation, and a peripheral edge adjacent to the central portion 17 on the negative direction side of the X axis. It has a portion 18 and a peripheral portion 19 adjacent to the central portion 17 on the positive direction side of the X-axis. The central portion 17 and the peripheral portions 18 and 19 are provided in a band shape along the Z'axis direction, respectively, and extend from one end to the other end of the crystal piece 11 facing each other in the Z'axis direction. Therefore, the first main surface 11a of the crystal piece 11 includes the first main surface 17a of the central portion 17, the first main surface 18a of the peripheral portion 18, and the first main surface 19a of the peripheral portion 19. Similarly, the second main surface 11b of the crystal piece 11 includes the second main surface 17b of the central portion 17, the second main surface 18b of the peripheral portion 18, and the second main surface 19b of the peripheral portion 19.

The crystal piece 11 has a mesa-shaped structure in which the central portion 17 is thicker than the peripheral portions 18 and 19. Specifically, a first side surface 12a connecting the first main surface 17a of the central portion 17 and the first main surface 18a of the peripheral portion 18 is formed between the central portion 17 and the peripheral portion 18, and the central portion 17 is formed. A second side surface 12b is formed which connects the second main surface 17b of the above and the second main surface 18b of the peripheral edge portion 18. Similarly, a step is formed between the central portion 17 and the peripheral portion 19, and a first side surface 13a connecting the first main surface 17a of the central portion 17 and the first main surface 19a of the peripheral portion 19 is formed. A second side surface 13b is formed that connects the second main surface 17b of the central portion 17 and the second main surface 19b of the peripheral portion 19. As described above, the first main surface 11a and the second main surface 11b of the crystal piece 11 have a step between the central portion 17 and the peripheral portion 18 and between the central portion 17 and the peripheral portion 19, respectively. It is formed.

The first side surfaces 12a and 13a and the second side surfaces 12b and 13b of the crystal piece 11 extend in directions orthogonal to the first main surface 11a and the second main surface 11b of the crystal piece 11, respectively. In other words, the first side surfaces 12a, 13a and the second side surfaces 12b, 13b of the crystal piece 11 extend along the Y'Z'plane. The first side surfaces 12a and 13a and the second side surfaces 12b and 13b of the crystal piece 11 may be formed in a tapered shape, respectively. For example, the first side surface 12a and the second side surface 13b extend in a direction inclined from the Y'axis positive direction to the X axis positive direction, and the second side surface 12b and the first side surface 13a extend from the Y'axis positive direction to the X axis negative direction. It may extend in a direction inclined in the direction. Further, in the example shown in FIG. 1, a mode is shown in which a step is formed on both the first main surface 11a side and the second main surface 11b side between the central portion 17 and the peripheral portions 18 and 19. As a modification, a step may be formed only on one of the first main surface 11a side and the second main surface 11b side.

The crystal piece 11 is not limited to the above as long as it has a shape in which a side surface is formed between the central portion and the peripheral portion. For example, the crystal piece 11 may be provided with a peripheral edge portion adjacent to the central portion 17 in the positive direction or the negative direction of the Z'axis. Further, the crystal piece 11 is not limited to the mesa-shaped structure, and the central portion 17 may have an inverted mesa-shaped structure thinner than the peripheral portions 18 and 19. It may be a convex shape or a behel shape in which the change in thickness between the central portion 17 and the peripheral portions 18 and 19 changes continuously. As will be described later, a slit may be formed between the central portion and the peripheral portion. The shape of the crystal piece 11 is not limited to a plate shape. For example, when the first main surface 11a is viewed in a plan view, a pair of parallel arms and a connecting portion connecting the arms are connected. It may be a comb tooth type having, or the like.

In the examples shown in FIGS. 1 and 2, the crystal vibrating element 10 has an X-axis parallel to the first direction D1, a Z'axis parallel to the second direction D2, and a Y'axis parallel to the third direction D3. It is set to be parallel to.

The crystal vibration element 10 includes a first excitation electrode 14a and a second excitation electrode 14b that form a pair of electrodes. The first excitation electrode 14a is provided on the first main surface 17a of the central portion 17. Further, the second excitation electrode 14b is provided on the second main surface 17b of the central portion 17. The first excitation electrode 14a and the second excitation electrode 14b face each other with the crystal piece 11 interposed therebetween in the third direction D3. The first excitation electrode 14a and the second excitation electrode 14b are arranged so that substantially the entire surface overlaps on the XZ'plane. The first excitation electrode 14a and the second excitation electrode 14b each have a long side parallel to the X-axis direction, a short side parallel to the Z'axis direction, and a thickness parallel to the Y'axis direction. ..

When the first main surface 17a of the central portion 17 is viewed in a plan view, the outer edge of the first excitation electrode 14a extends to the boundary with the first side surface 12a in the central portion 17. Further, when the second main surface 17b of the central portion 17 is viewed in a plan view, the outer edge of the second excitation electrode 14b extends to the boundary with the second side surface 12b in the central portion 17. In other words, the outer shape of the main surface of the first excitation electrode 14a facing the central portion 17 coincides with the outer shape of the first main surface 17a of the central portion 17. Further, the outer shape of the main surface of the second excitation electrode 14b facing the central portion 17 coincides with the outer shape of the second main surface 17b of the central portion 17. According to this, the utilization efficiency of the region contributing to the excitation in the central portion 17 is improved, and the crystal vibrating element 10 can be miniaturized. Further, the confinement efficiency of the vibration excited in the central portion 17 can be improved.

The crystal oscillator 10 has a pair of first extraction electrodes 15a and a second extraction electrode 15b, and a pair of first connection electrodes 16a and a second connection electrode 16b. The first connection electrode 16a is electrically connected to the first excitation electrode 14a via the first extraction electrode 15a. Further, the second connection electrode 16b is electrically connected to the second excitation electrode 14b via the second extraction electrode 15b. The first connection electrode 16a and the second connection electrode 16b are terminals for electrically connecting the first excitation electrode 14a and the second excitation electrode 14b to the base member 30, respectively.

The first extraction electrode 15a covers a part of the first excitation electrode 14a when the first main surface 11a of the crystal piece 11 is viewed in a plan view, and the central portion 17 to the first side surface 12a are covered by the first main surface 11a. It extends through the peripheral portion 18. The first extraction electrode 15a is further routed over the first main surface 18a of the peripheral edge portion 18 to reach the second main surface 18b. The second extraction electrode 15b covers a part of the second excitation electrode 14b when the second main surface 11b of the crystal piece 11 is viewed in a plan view, and the second main surface 11b covers the central portion 17 to the second side surface 12b. It extends through the peripheral portion 18. Since the first extraction electrode 15a covers at least a part of the first excitation electrode 14a, the contact area between the first excitation electrode 14a and the first extraction electrode 15a increases, and the electrical connection becomes stable. Further, since damage such as electrode peeling is likely to occur at the corner portion of the crystal piece 11, damage to the first excitation electrode 14a is suppressed by covering the end portion of the first excitation electrode 14a with the first extraction electrode 15a. it can. Therefore, deterioration of the frequency characteristics of the crystal vibrating element 10 can be suppressed.

The first extraction electrode 15a may be adjacent to the first excitation electrode 14a without covering the first excitation electrode 14a when the first main surface 11a of the crystal piece 11 is viewed in a plan view. Further, the first extraction electrode 15a may cover the entire first excitation electrode 14a when the first main surface 11a of the crystal piece 11 is viewed in a plan view. Similarly, the second extraction electrode 15b may be adjacent to the second excitation electrode 14b when the second main surface 11b of the crystal piece 11 is viewed in a plan view, or may cover the entire second excitation electrode 14b. ..

The first connection electrode 16a is provided on the second main surface 18b of the peripheral edge portion 18, and the second connection electrode 16b is provided on the second main surface 18b of the peripheral edge portion 18. The first extraction electrode 15a and the first connection electrode 16a are integrally formed. The second extraction electrode 15b and the second connection electrode 16b are also integrally formed.

As shown in FIG. 3, each of the above-mentioned various electrodes has a multi-layer structure. The first excitation electrode 14a includes a first contact layer 51 and a first conductive layer 52. The first adhesive layer 51 has higher adhesion to the crystal piece 11 than the first conductive layer 52. The first adhesion layer 51 is provided on the side of the first main surface 11a of the crystal piece 11, and is in contact with the first main surface 17a of the central portion 17. The first conductive layer 52 has higher conductivity than the first adhesive layer 51 and has higher chemical stability than the first adhesive layer 51. The first conductive layer 52 covers the first adhesive layer 51 when the first main surface 11a of the crystal piece 11 is viewed in a plan view. Similarly, the second excitation electrode 14b is also provided on the second main surface 11b side of the crystal piece 11, and the first contact layer 53 in contact with the second main surface 17b of the central portion 17 and the second main surface 11b of the crystal piece 11 Is provided with a first conductive layer 54 that covers the first adhesive layer 53 when viewed in a plan view. However, the first excitation electrode 14a and the second excitation electrode 14b are not limited to a two-layer structure, and may have a single-layer structure or a multi-layer structure of three or more layers.

The first extraction electrode 15a includes a second adhesion layer 55 and a second conductive layer 56. The second adhesive layer 55 has higher adhesion to the crystal piece 11 than the second conductive layer 56. The second adhesion layer 55 is provided on the side of the first main surface 11a of the crystal piece 11, and is in contact with the first main surface 17a and the second main surface 17b of the central portion 17. The second adhesion layer 55 also contacts the second side surface 12b and covers the end portion of the first excitation electrode 14a, that is, the end portion of the first conductive layer 52. The second conductive layer 56 has higher conductivity than the second adhesive layer 55 and has higher chemical stability than the second adhesive layer 55. The second conductive layer 56 covers the second adhesive layer 55 when the first main surface 11a and the second main surface 11b of the crystal piece 11 are viewed in a plan view. That is, in the region where the first extraction electrode 15a of the central portion 17 overlaps the first excitation electrode 14a, the electrode has a four-layer structure, the first conductive layer 52 covers the first adhesion layer 51, and the second adhesion layer 55 The first conductive layer 52 is covered, and the second conductive layer 56 covers the second adhesive layer 55.

Since the first connection electrode 16a is integrally formed with the first extraction electrode 15a, it includes the second adhesion layer 55 and the second conductive layer 56 in the same manner as the first extraction electrode 15a. Although not shown in FIG. 3, the second extraction electrode 15b and the second connection electrode 16b also include a second adhesion layer and a second conductive layer. However, the first extraction electrode 15a, the second extraction electrode 15b, the first connection electrode 16a, and the second connection electrode 16b are not limited to the two-layer structure, and may have a single-layer structure or three or more layers. It may have a multi-layer structure of.

The first contact layer 51 of the first excitation electrode 14a, the first contact layer 53 of the second excitation electrode 14b, and the second contact layer 55 of the first extraction electrode 15a are each made of a metal material containing chromium (Cr). .. The first conductive layer 52 of the first excitation electrode 14a, the first conductive layer 54 of the second excitation electrode 14b, and the second conductive layer 56 of the first extraction electrode 15a are each made of a metal material containing gold (Au). .. By providing a Cr layer with high reactivity with oxygen on the base, the adhesion between the crystal piece and the electrode is improved, and by providing an Au layer with low reactivity with oxygen on the surface, deterioration of the electrode due to oxidation is suppressed. To. According to this, the reliability of the crystal vibrating element can be improved.

As shown in FIG. 3, the thickness of the portion of the first excitation electrode 14a exposed from the first extraction electrode 15a (hereinafter, the thickness along the third direction D3 is simply represented as “thickness”) T1. , The thickness of the portion of the first excitation electrode 14a that overlaps with the first extraction electrode 15a is smaller than the thickness T2 (T1 <T2). The thickness T3 of the portion provided at the central portion 17 of the first extraction electrode 15a is smaller than the thickness T4 of the portion provided at the peripheral portion 18 of the first extraction electrode 15a (T3 <T4). The thickness T1 portion of the first excitation electrode 14a has the same thickness as the first adhesion layer 51 and the thickness of the first conductive layer 52 is smaller than that of the portion having a thickness T2. The thickness T3 portion of the first extraction electrode 15a has the same thickness as the second adhesion layer 55 and the thickness of the second conductive layer 56 is smaller than that of the portion having a thickness T4. In this way, the frequency characteristic of the crystal vibrating element 10 can be adjusted by scraping the surface of the electrode provided in the central portion 17 and adjusting the thickness of the electrode.

In the configuration example shown in FIG. 3, the electrode provided in the central portion 17 has a smaller thickness in the portion of the central portion 17 facing the entire surface of the first main surface 17a, but at least in the central portion 17. It suffices if the thickness is reduced in the portion of the first main surface 17a facing the central portion. Further, the surface of the electrode provided in the central portion 17 does not necessarily have to be scraped, and the thickness T1 and the thickness T2 of the first excitation electrode 14a may be equal to the thickness T3 of the first extraction electrode 15a. It may be equal to the thickness T4.

The shape of the lid member 20 is concave, and is a box shape that opens toward the first main surface 32a of the base member 30. The lid member 20 is joined to the base member 30. An internal space 26 surrounded by the lid member 20 and the base member 30 is provided. The crystal vibrating element 10 is housed in the internal space 26. The shape of the lid member 20 is not particularly limited as long as the crystal vibrating element 10 can be accommodated. In one example, the shape of the lid member 20 is rectangular when the main surface of the top surface portion 21 is viewed in a plane. The rectangular lid member 20 is defined by, for example, a long side parallel to the first direction D1, a short side parallel to the second direction D2, and a height parallel to the third direction D3. The material of the lid member 20 is not particularly limited, but is made of a conductor such as metal. The lid member 20 made of a conductor has an electromagnetic shielding function of shielding at least a part of electromagnetic waves to the internal space 26.

As shown in FIG. 2, the lid member 20 has an inner surface 24 and an outer surface 25. The inner surface 24 is a surface on the inner space 26 side, and the outer surface 25 is a surface on the opposite side to the inner surface 24. The lid member 20 is connected to the top surface portion 21 facing the first main surface 32a of the base member 30 and the outer edge of the top surface portion 21, and is a side wall extending in a direction intersecting the main surface of the top surface portion 21. It has a part 22 and. Further, the lid member 20 has a facing surface 23 facing the first main surface 32a of the base member 30 at the concave opening end portion (the end portion of the side wall portion 22 on the side closer to the base member 30). The facing surface 23 extends in a frame shape so as to surround the crystal vibrating element 10.

The base member 30 holds the crystal vibrating element 10 in an excitable manner. The base member 30 has a flat plate shape. The base member 30 has a long side parallel to the first direction D1 direction, a short side parallel to the second direction D2, and a side in the thickness direction parallel to the third direction D3.

The base member 30 has a base 31. The substrate 31 has a first main surface 32a (front surface) and a second main surface 32b (back surface) facing each other. The substrate 31 is a sintered material such as an insulating ceramic (alumina).

The base member 30 has electrode pads 33a and 33b provided on the first main surface 32a and external electrodes 35a, 35b, 35c and 35d provided on the second main surface 32b. The electrode pads 33a and 33b are terminals for electrically connecting the base member 30 and the crystal vibrating element 10. Further, the external electrodes 35a, 35b, 35c, 35d are terminals for electrically connecting a circuit board (not shown) and the crystal oscillator 1. The electrode pad 33a is electrically connected to the external electrode 35a via the via electrode 34a extending in the third direction D3, and the electrode pad 33b is connected to the external electrode via the via electrode 34b extending in the third direction D3. It is electrically connected to 35b. The via electrodes 34a and 34b are formed in the via holes penetrating the substrate 31 in the third direction D3. The external electrodes 35c and 35d may be dummy electrodes to which an electric signal or the like is not input / output, or may be ground electrodes that supply a ground potential to the lid member 20 to improve the electromagnetic shield function of the lid member 20. The external electrodes 35c and 35d may be omitted.

The conductive holding members 36a and 36b electrically connect the pair of connection electrodes 16a and 16b of the crystal vibrating element 10 to the pair of electrode pads 33a and 33b of the base member 30, respectively. Further, the conductive holding members 36a and 36b hold the crystal vibrating element 10 on the first main surface 32a of the base member 30 so as to be excited. The conductive holding members 36a and 36b are made of, for example, a conductive adhesive containing a thermosetting resin or an ultraviolet curable resin whose main component is an epoxy resin or a silicone resin, in order to impart conductivity to the adhesive. Contains additives such as conductive particles of. In addition, a filler may be added to the adhesive to increase the strength of the adhesive or to maintain a distance between the base member and the crystal oscillator.

A sealing member 37 is provided on the first main surface 32a of the base member 30. In the example shown in FIG. 1, the sealing member 37 has a rectangular frame shape when the first main surface 32a is viewed in a plan view. When the first main surface 32a is viewed in a plan view, the electrode pads 33a and 33b are arranged inside the sealing member 37, and the sealing member 37 is provided so as to surround the crystal vibration element 10. The sealing member 37 is made of a conductive material. For example, by configuring the sealing member 37 with the same material as the electrode pads 33a and 33b, the sealing member 37 can be provided at the same time in the step of providing the electrode pads 33a and 33b.

The joining member 40 is provided over the entire circumference of the lid member 20 and the base member 30. Specifically, the joining member 40 is provided on the sealing member 37 and is formed in a rectangular frame shape. The sealing member 37 and the joining member 40 are sandwiched between the facing surface 23 of the side wall portion 22 of the lid member 20 and the first main surface 32a of the base member 30.

When both the lid member 20 and the base member 30 are joined with the sealing member 37 and the joining member 40 sandwiched between them, the crystal vibrating element 10 is surrounded by the lid member 20 and the base member 30 in an internal space (cavity). It is sealed in 26. In this case, the internal space 26 is preferably in a vacuum state where the atmospheric pressure is lower than the atmospheric pressure. According to this, it is possible to reduce the time-dependent fluctuation of the frequency characteristics of the crystal oscillator 1 due to the oxidation of the first excitation electrode 14a and the second excitation electrode 14b.

In the crystal oscillator 1, an alternating electric field is applied between the first excitation electrode 14a and the second excitation electrode 14b constituting the crystal vibrating element 10 via the external electrodes 35a and 35b of the base member 30. As a result, the crystal piece 11 vibrates in a predetermined vibration mode such as a thick slip vibration mode (Thickness Shear Vibration Mode), and resonance characteristics associated with the vibration can be obtained.

Next, a method of manufacturing the crystal vibrating element 110 according to the first embodiment will be described with reference to FIGS. 4 to 10. FIG. 4 is a flowchart schematically showing a part of the manufacturing method of the crystal vibrating element according to the first embodiment. FIG. 5 is a flowchart schematically showing the manufacturing method of the crystal vibrating element according to the first embodiment, following the flowchart shown in FIG. FIG. 6 is a cross-sectional view schematically showing a step of etching a crystal piece. FIG. 7 is a cross-sectional view schematically showing a step of providing the second adhesion layer and the second conductive layer. FIG. 8 is a cross-sectional view schematically showing a step of patterning a photoresist. FIG. 9 is a cross-sectional view schematically showing a step of etching the second adhesive layer and the second conductive layer. FIG. 10 is a cross-sectional view schematically showing a step of scraping the electrode surface in the central portion.

First, a crystal piece is prepared (S11). The crystal piece 111 is a flat plate-shaped member cut out from an artificial quartz so that the XZ'plane is the main surface. The surface of the crystal piece 111 is flattened. For example, a polishing process such as chemical mechanical polishing is used for the flattening process. In the crystal vibrating element in the thickness sliding vibration mode, the size of the thickness of the crystal piece has a great influence on the frequency characteristics of the piezoelectric vibrating element. Therefore, the thickness of the crystal piece may be adjusted by the polishing process in this step so that the target frequency characteristic can be realized.

Next, the first adhesion layer is provided (S12). The first adhesion layers 151 and 153 are formed so as to cover the entire surfaces of the first main surface 111a and the second main surface 111b of the crystal piece 111. The first adhesion layers 151 and 153 before patterning correspond to an integral series of metal films wrapping the crystal piece 111. The first adhesion layers 151 and 153 are formed by, for example, depositing a metal material containing Cr on the surface of the quartz piece 111 by sputtering. The first adhesion layers 151 and 153 are formed so that the thickness is 1 nm or more and 20 nm or less. When the thickness of the first adhesion layers 151 and 153 is 1 nm or more, it is possible to suppress a decrease in the adhesion force of the first excitation electrode 114a and the second excitation electrode 114b to the crystal piece 111. As a result, the occurrence of damage such as peeling of the first excitation electrode 114a and the second excitation electrode 114b can be reduced. Further, when the thickness of the first adhesion layers 151 and 153 is 20 nm or less, deterioration of the vibration characteristics of the crystal vibrating element 110 can be suppressed.

Next, the first conductive layer is provided (S13). The first conductive layers 152 and 154 are formed so as to cover the first contact layers 151 and 153 on the first main surface 111a side and the second main surface 111b side of the crystal piece 111, respectively. The first conductive layers 152 and 154 before being patterned correspond to an integral series of metal films surrounding the first adhesive layers 151 and 153 that enclose the crystal piece 111. The first conductive layers 152 and 154 are formed by depositing a metal material containing Au on the surface of the first adhesion layers 151 and 153 by sputtering. The first conductive layers 152 and 154 are formed so as to have a thickness of 1 nm or more and 500 nm or less. When the thickness of the first conductive layers 152 and 154 is 1 nm or more, sufficient conductivity is given to the first excitation electrode 114a and the second excitation electrode 114b. Further, the first conductive layers 152 and 154 can suppress the oxidation of the first adhesive layers 151 and 153 corresponding to the base. Therefore, deterioration of the vibration characteristics of the crystal vibration element 110 can be suppressed. Further, when the thickness of the first conductive layers 152 and 154 is 500 nm or less, the amount of the metal material containing Au can be reduced. Therefore, the manufacturing cost of the crystal vibrating element 110 can be reduced, and the time required for forming the first conductive layers 152 and 154 can be shortened.

The film forming method of the first adhesion layers 151, 153 and the first conductive layers 152, 154 is not limited to sputtering, and is dry plating such as PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition), or electroplating. It may be formed by wet plating such as or electroless plating.

Next, a photoresist is provided (S14). The photoresist is formed so as to cover the entire surface of the first conductive layers 152 and 154. First, the photoresist solution is applied to the entire surface of the first conductive layers 152 and 154 by a spin coating method, an injection method, a printing method such as a gravure coating, or the like. Next, the photoresist solution is dried to remove the solvent and solidified to form a photoresist made of a photosensitive resin.

Next, the photoresist is patterned (S15). From the viewpoint of adaptability to microfabrication, the photoresist is preferably a positive photosensitive resin that removes the exposed portion by melting. When a positive photosensitive resin is used, the photoresist is exposed in a state where the region corresponding to the central portion 117 is shielded from light with a photomask. Then, the portion exposed by the developer is washed away. As a result, the shape of the light-shielding region of the photomask is transferred to the photoresist. As a result, the outer shape of the central portion 117 is patterned on the photoresist remaining on the first conductive layers 152 and 154. The photoresist may be a negative-type photosensitive resin that removes the light-shielded portion by dissolution.

Next, the first conductive layer is etched (S16). The removal processing of the first conductive layers 152 and 154 is carried out by wet etching using a first etching solution containing an aqueous potassium iodide solution as a main component. Since the potassium iodide aqueous solution has a high etching rate for Au and a low etching rate for Cr, it is possible to leave the first adhesive layers 151 and 153 corresponding to the base while etching the exposed first conductive layers 152 and 154. it can.

Next, the first adhesion layer is etched (S17). The removal processing of the first adhesion layers 151 and 153 is carried out by wet etching using a second etching solution containing an aqueous solution of cerium ammonium nitrate as a main component. Since the cerium ammonium nitrate aqueous solution has a low etching rate for Au and a high etching rate for Cr, the exposed first adhesion is suppressed while suppressing the corrosion of the first conductive layers 152 and 154 that remain covered with the patterned photoresist. Layers 151 and 153 can be etched.

As described above, as the first etching solution and the second etching solution, etching solutions having different etching rates for the first adhesion layer and the first conductive layer are appropriately selected. The etched first conductive layer 152 and the first contact layer 151 form the outer shape of the first excitation electrode 114a, and the etched first conductive layer 154 and the first contact layer 153 form the outer shape of the second excitation electrode 114b. To do. The outer shape of the first excitation electrode 114a and the second excitation electrode 114b is not limited to wet etching, and may be formed by other removal processing such as dry etching.

Next, the crystal piece is etched (S18). Here, the first excitation electrode 114a and the second excitation electrode 114b are used as metal masks for protecting the central portion 117 of the crystal piece 111, and the peripheral edge portion 118 and the peripheral edge portion 119 are removed. The removal process of the crystal piece 111 is carried out by wet etching with hydrofluoric acid. As a result, as shown in FIG. 6, a step is generated between the central portion 117 and the peripheral portion 118, and the first side surface connecting the first main surface 117a of the central portion 117 and the first main surface 118a of the peripheral portion 118. 112a is formed, and a second side surface 112b connecting the second main surface 117b of the central portion 117 and the second main surface 118b of the peripheral portion 118 is formed. Similarly, a first side surface 113a connecting the first main surface 117a of the central portion 117 and the first main surface 119a of the peripheral portion 119 is formed, and the second main surface 117b of the central portion 117 and the second main surface of the peripheral portion 119 are formed. A second side surface 113b connecting the surface 119b is formed. That is, the crystal piece 111 becomes a concavo-convex member having a mesa-shaped structure on both sides of the first main surface 111a and the second main surface 111b by removing a part from the flat plate-shaped member. At this time, the first excitation electrode 114a used as a metal mask remains on the first main surface 117a of the central portion 117, and the second excitation electrode 114b used as a metal mask remains on the second main surface 117b of the central portion 117. Remains. The formation of the mesa-shaped structure of the crystal piece 111 is not limited to wet etching, and may be performed by other removal processing such as dry etching. However, it is desirable that the crystal piece 111 is removed by wet etching from the viewpoint of reducing damage to the first excitation electrode 114a and the second excitation electrode 114b.

If an excitation electrode is provided in the center of the quartz piece after the mesa-shaped structure is formed on the quartz piece, the thickness of the photoresist becomes non-uniform due to the surface tension of the photoresist solution or the like. For example, photoresists become thinner at the corners of steps and thicker at flat areas. Therefore, the patterning accuracy of the photoresist is lowered, and the pattern shape of the photoresist near the corners of the step is not stable. Then, it becomes difficult to form an excitation electrode having a uniform film thickness up to the edge of the main surface of the central portion, and the outer edge of the excitation electrode is located inside the main surface of the central portion when the main surface of the central portion is viewed in a plan view. Will be done. As described above, when the first excitation electrode 114a is used as a metal mask for forming a mesa-shaped structure on the crystal piece 111, the first excitation electrode 114a is placed on the edge of the first main surface 117a of the central portion 117, that is, the central portion. It can be formed up to the boundary with the first side surface 112a of 117. By matching the shapes of the first main surface 117a of the central portion 117 and the first excitation electrode 114a, fluctuations in the shape of the first excitation electrode 114a can be suppressed, and fluctuations in the frequency characteristics of the crystal vibrating element 110 can be suppressed. Similarly, the second excitation electrode 114b can be formed up to the boundary with the second side surface 112b of the central portion 117.

Next, a second adhesion layer is provided (S21). As shown in FIG. 7, the second adhesion layer 155 that constitutes a part of the first extraction electrode 115a and a part of the second extraction electrode (not shown) is a surface of the peripheral portion 118 of the crystal piece 111, the first. It is formed so as to cover the surface of the excitation electrode 114a and the surface of the second excitation electrode 114b. The second adhesion layer 155 before patterning corresponds to an integral series of metal films surrounding the crystal piece 111, the first excitation electrode 114a, and the second excitation electrode 114b. The second adhesion layer 155 can be formed by the same method as the first adhesion layers 151, 153 so as to have the same structure as the first adhesion layers 151, 153. That is, the second adhesion layer 155 is a metal film in which a metal material containing Cr is deposited by sputtering, and the thickness thereof is 1 nm or more and 20 nm or less.

Next, a second conductive layer is provided (S22). As shown in FIG. 7, the second conductive layer 156 that constitutes a part of the first extraction electrode 115a and a part of the second extraction electrode (not shown) is formed so as to cover the second adhesion layer 155. .. The second conductive layer 156 before patterning corresponds to an integral series of metal films surrounding the second adhesive layer 155 that encloses the crystal piece 111. The second conductive layer 156 can be formed so as to have the same configuration by the same method as the first conductive layers 152 and 154. That is, the second conductive layer 156 is a metal film in which a metal material containing Au is deposited by sputtering, and the thickness thereof is 1 nm or more and 500 nm or less.

Next, a photoresist is provided (S23). The photoresist 161 is formed so as to cover the entire surface of the second conductive layer 156. The photoresist 161 provided in step S23 can be formed so as to have the same configuration by the same method as the photoresist provided in step S14.

Next, the photoresist is patterned (S24). The patterning in step S24 is carried out by the same method as in step S15. As shown in FIG. 8, the photoresist 161 is patterned with the outer shapes of the first extraction electrode 115a and the second extraction electrode (not shown) by a photolithography method.

Next, the second conductive layer is etched (S25). At this time, by using the same etching solution as the first etching solution used in step S16, the exposed second conductive layer 156 can be etched while the second adhesive layer 155 corresponding to the base can be left.

Next, the second adhesion layer is etched (S26). At this time, by using an etching solution similar to the second etching solution used in step S17, the exposed second adhesion is suppressed while suppressing the erosion of the second conductive layer 156 that remains covered with the patterned photoresist. Layer 155 can be etched. As shown in FIG. 9, by etching the second adhesion layer 155, the first conductive layer 152 of the first excitation electrode 114a and the first conductive layer 154 of the second excitation electrode 114b are exposed. Since the second etching solution has a low etching rate with respect to Au, it is possible to suppress the erosion of the exposed first excitation electrode 114a into the first conductive layer 152 and the second excitation electrode 114b by the etching solution into the first conductive layer 154.

As described above, by forming the excitation electrode and the extraction electrode into a two-layer structure and performing wet etching with etching solutions having different etching rates for each layer, the extraction electrode can be patterned while suppressing damage to the excitation electrode. The formation of the extraction electrode is not limited to wet etching using the photolithography method. The extraction electrode may be patterned by a method in which a sputtering mask in which the shape of the extraction electrode is patterned is arranged around the crystal piece 111, and the second adhesion layer 155 and the second conductive layer 156 are sputtered through the sputtering mask.

Next, the surface of the electrode at the center is scraped (S26). As shown in FIG. 10, the surface of the first excitation electrode 114a and the surface of the first extraction electrode 115a facing the first main surface 117a of the central portion 117 are scraped by ion milling. As a result, the thickness of the electrode formed in the central portion 117 is reduced, and the frequency characteristic of the crystal vibrating element 110 is adjusted. Through the above steps, the crystal vibrating element 110 having a desired frequency characteristic is manufactured. In step S26, the surface may be scraped by at least one of the electrodes on the first main surface 117a side and the second main surface 117b side of the central portion 117, and both electrodes may be used.

The other embodiments will be described below. In each of the following embodiments, the matters common to the above-described first embodiment will be omitted, and only the differences will be described. The configuration with the same reference numerals as those in the first embodiment has the same configurations and functions as those in the first embodiment, and detailed description thereof will be omitted. No mention is made of similar effects with similar configurations.

<Second Embodiment>
The configuration of the crystal vibration element 210 according to the second embodiment will be described with reference to FIG. FIG. 11 is a cross-sectional view schematically showing the configuration of the crystal oscillator according to the second embodiment.

The crystal vibrating element 210 includes a crystal piece 211, a first excitation electrode 214a, a second excitation electrode 214b, a first extraction electrode 215a, and a first connection electrode 216a. The crystal piece 211 includes a central portion 217 and peripheral portions 218 and 219. In the crystal piece 211, a first side surface 212a connecting the first main surface 217a and the first main surface 218a is formed between the central portion 217 and the peripheral portion 218, and the second main surface 217b and the second main surface 217b are formed. A second side surface 212b connecting the two main surfaces 218b is formed. In the crystal piece 211, a first side surface 213a connecting the first main surface 217a and the first main surface 219a is formed between the central portion 217 and the peripheral portion 219, and the second main surface 217b and the second main surface 217b are formed. A second side surface 213b connecting the two main surfaces 219b is formed. The first excitation electrode 214a includes a first contact layer 251 and a first conductive layer 252. The second excitation electrode 214b includes a first adhesion layer 253 and a first conductive layer 254. The first extraction electrode 215a includes a second adhesion layer 255 and a second conductive layer 256.

The difference from the crystal vibrating element 10 according to the first embodiment is that the crystal piece 211 has an inverted mesa type structure. That is, the thickness of the peripheral portions 218 and 219 is larger than the thickness of the central portion 217. Specifically, on both the first main surface 217a and the second main surface 217b, the central portion 217 is thinner than the peripheral portions 218 and 219, and the crystal piece 211 has a double-sided inverted mesa type structure. In addition, in only one of the first main surface 217a and the second main surface 217b, the central portion 217 may be a crystal piece 211 having a single-sided inverted mesa type structure thinner than the peripheral portions 218 and 219.

Even in such a crystal vibrating element 210, the same effect as described above can be obtained.

<Third Embodiment>
The configuration of the crystal oscillator 900 according to the third embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 is an exploded perspective view schematically showing the configuration of the crystal oscillator according to the third embodiment. FIG. 13 is a cross-sectional view schematically showing the configuration of the crystal oscillator according to the third embodiment.

The crystal oscillator 900 has a so-called sandwich structure in which the crystal vibrating element 910 is sandwiched between the first lid member 920a and the second lid member 920b. The crystal vibrating element 910 includes a crystal piece 911, a first excitation electrode 914a, a second excitation electrode 914b, a first extraction electrode 915a, and a second extraction electrode 915b. The first lid member 920a is joined to the first main surface 911a of the crystal piece 911 with the first sealing member 937a interposed therebetween, and the second lid member 920b sandwiches the second sealing member 937b with the first main surface 911a of the crystal piece 911. 2 It is joined to the main surface 911b.

When the first main surface 911a of the crystal piece 911 is viewed in a plan view, the crystal piece 911 includes a central portion 917 and a peripheral portion 919 that surrounds the central portion 917 at intervals. That is, a slit is formed between the central portion 917 and the peripheral portion 919. The thickness of the peripheral portion 919 is larger than the thickness of the central portion 917. The central portion 917 is supported by the peripheral portion 919 by a pair of support portions 918. The thickness of the support portion 918 is smaller than the thickness of the central portion 917. The support portion 918 corresponds to a part of the peripheral portion. Between the support portion 918 and the central portion 917, a first side surface 912a connecting the first main surface 917a of the central portion 917 and the first main surface 918a of the support portion 918 is formed, and the second main surface of the central portion 917 is formed. A second side surface 912b is formed that connects the 917b and the second main surface 918b of the support portion 918. A third side surface 913 is formed at the slit-side end of the central portion 917 to connect the first main surface 917a and the second main surface 917b of the central portion 917. The first lid member 920a is joined to the first main surface 919a of the peripheral edge portion 919, and the second lid member 920b is joined to the second main surface 919b of the peripheral edge portion 919.

When the first main surface 917a of the central portion 917 is viewed in a plan view, the outer edge of the first excitation electrode 914a extends to the boundary with the first side surface 912a and the boundary with the third side surface 913 in the central portion 917. There is. When the second main surface 917b of the central portion 917 is viewed in a plan view, the outer edge of the second excitation electrode 914b extends to the boundary with the second side surface 912b and the boundary with the third side surface 913 in the central portion 917. There is. The first extraction electrode 915a covers a part of the first excitation electrode 914a, passes through one of the first side surface 912a and the pair of support portions 918, and is routed to the first main surface 919a of the peripheral portion 919. .. The second extraction electrode 915b covers a part of the second excitation electrode 914b, passes through the other of the second side surface 912b and the pair of support portions 918, and is routed to the second main surface 919b of the peripheral portion 919. ..

Even in such a crystal vibrating element 910, the same effect as described above can be obtained.

<Fourth Embodiment>
The configuration of the crystal vibration element 410 according to the fourth embodiment will be described with reference to FIG. FIG. 14 is a perspective view schematically showing the configuration of the crystal vibration element according to the fourth embodiment.

The difference between the present embodiment and the first embodiment is that the peripheral edge portion PR1 adjacent to the central portion 417 on the positive direction side of the Z'axis and the peripheral edge portion PR2 adjacent to the central portion 417 on the negative direction side of the Z'axis. And, it is a point to prepare. The peripheral edge PR1 connects one ends of the peripheral edges 418 and 419, and the peripheral edge PR2 connects the other ends of the peripheral edges 418 and 419. When the first main surface 411a of the crystal piece 411 is viewed in a plan view, the peripheral portions 418, 419, PR1 and PR2 are provided in a rectangular frame shape, and the central portion 417 is surrounded by the peripheral portions 418, 419, PR1 and PR2. It is provided in an island shape. The first main surface 417a of the central portion 417 is provided with the first excitation electrode 414a over the entire surface, and the peripheral portion 418 is provided with the first extraction electrode 415a and the first connection electrode 416a. Even on the second main surface side (not shown), the central portion 417 has an island shape surrounded by peripheral portions 418, 419, PR1 and PR2, and the second excitation is performed over the entire surface of the second main surface of the central portion 417. Electrodes are provided. Even in such a crystal vibrating element 410, the same effect as described above can be obtained.

As described above, if the first and second excitation electrodes are formed over the entire surfaces of the first and second main surfaces of the central portion, the shapes of the central portion and the peripheral portion are not particularly limited. .. For example, the shape of the central portion may be a circular or elliptical shape when the first main surface of the crystal piece is viewed in a plane, or may be a polygonal shape other than a quadrangle.

In addition to the step formed between the peripheral portion and the central portion, a step may be further formed on the first main surface side and the second main surface side of the quartz piece. For example, a thin-walled region and a thick-walled region are formed in the central portion, the thin-walled region in the central portion is adjacent to the peripheral edge portion, and the thick-walled region in the central portion is adjacent to the side opposite to the peripheral edge portion of the thin-walled region. The thin-walled region at the center may be formed in a strip shape extending from one end to the other end facing each other in the Z'axis direction of the quartz piece. At this time, the thick-walled region in the central portion may be formed in a band shape over the entire width of the crystal piece as in the thin-walled region in the central portion, or may be formed in an island shape surrounded by the thin-walled region in the central portion. When the thick region in the central portion is formed in a band shape, the thick region in the central portion may be sandwiched between the thin region in the central portion in the X-axis direction, and either in the positive direction or the negative direction in the X-axis direction. Only one may be adjacent to the central thin area. The positional relationship between the thin-walled region and the thick-walled region in the central portion may be reversed. That is, the thick-walled region in the central portion may be adjacent to the peripheral edge portion, and the thin-walled region in the central portion may be adjacent to the side opposite to the peripheral edge portion of the thick-walled region.

As a configuration in which a step is further formed on the first main surface side and the second main surface side of the crystal piece, for example, a thin-walled region and a thick-walled region are formed on the peripheral portion, and the thick-walled region on the peripheral portion is the central portion. The thin-walled region at the periphery is adjacent to the opposite side of the central portion of the thick-walled region. The thick region of the peripheral portion may be formed in a band shape over the entire width of the crystal piece. At this time, the central portion may be formed in a band shape over the entire width of the crystal piece as in the thick-walled region of the peripheral portion, or may be formed in an island shape surrounded by the thick-walled region of the peripheral portion. Further, the thick region of the peripheral portion may be formed in an island shape surrounded by the thin region. At this time, the central portion may be formed in a band shape over the entire width of the thick-walled region, or may be formed in an island shape surrounded by the thick-walled region. The positional relationship between the thick region and the thin region in the peripheral portion may be reversed. That is, the thin-walled region of the peripheral edge may be adjacent to the central portion, and the thick-walled region of the peripheral edge may be adjacent to the side opposite to the central portion of the thin-walled region.

As described above, according to one aspect of the present invention, the first main surface 111a and the second main surface 111b facing the first main surface 111a are provided, and the central side when the first main surface 111a is viewed in a plan view. The step of preparing the crystal piece 111 having the central portion 117 located at the center portion 117 and the peripheral portion 118 located outside the central portion 117, and the first excitation to the central portion 117 of the first main surface 111a of the crystal piece 111. In the process of providing the electrode 114a and using the first excitation electrode 114a as a metal mask to protect the central portion 117, a part of the peripheral portion 118 is removed, and the central portion 117 and the peripheral portion are removed on the first main surface 111a side of the crystal piece 111. It extends to the peripheral edge portion 118 on the first main surface 111a side of the crystal piece 111 so as to come into contact with the step of forming the first side surface 112a with the portion 118 and the first excitation electrode 114a used as a metal mask. Provided is a method for manufacturing a crystal vibrating element 110, which comprises a step of providing a first extraction electrode 115a.

According to the above aspect, the first excitation electrode can be formed up to the edge of the first main surface of the central portion, that is, the boundary with the first side surface of the central portion. By matching the shapes of the first main surface and the first excitation electrode in the central portion, fluctuations in the shape of the first excitation electrode can be suppressed, and fluctuations in the frequency characteristics of the crystal vibrating element can be suppressed. The utilization efficiency of the region contributing to excitation in the central portion is improved, and the crystal vibrating element can be miniaturized. In addition, the confinement efficiency of the vibration excited in the central portion can be improved.

The first extraction electrode 115a may pass through the first side surface 112a.

The first extraction electrode 115a may cover at least a part of the first excitation electrode 114a at the central portion 117 when the first main surface 111a of the crystal piece 111 is viewed in a plan view. According to this, the contact area between the first excitation electrode and the first extraction electrode is increased, and the electrical connection between the first excitation electrode and the first extraction electrode is stabilized. In addition, damage to the first excitation electrode can be suppressed, and deterioration of the frequency characteristics of the crystal vibrating element can be suppressed.

The step of providing the first excitation electrode 114a includes the step of providing the first contact layer 151 on the first main surface 111a side of the crystal piece 111 and the step of providing the first contact layer 151, which has higher conductivity than the first contact layer 151, and has higher conductivity than the first contact layer 151. The step of providing the first conductive layer 152 that covers the first adhesion layer 151 when the first main surface 111a of the above is viewed in a plan view may be included. According to this, by providing the first adhesion layer having high reactivity with oxygen on the base, the adhesion between the crystal piece and the first excitation electrode can be improved, and the first conductive layer having low reactivity with oxygen can be improved on the surface. The deterioration of the first excitation electrode due to oxidation can be suppressed by providing the above. That is, the reliability of the crystal vibrating element can be improved.

The steps of providing the first extraction electrode 115a include the step of providing the second contact layer 155 on the first main surface 111a side of the crystal piece 111 and the step of providing the second contact layer 155, which has higher conductivity than the second contact layer 155, and the crystal piece 111. A step of providing a second conductive layer 156 that covers the second adhesive layer 155 when the first main surface 111a of the above is viewed in a plan view may be included. According to this, by providing the second adhesion layer having high reactivity with oxygen on the base, the adhesion between the crystal piece and the first extraction electrode can be improved, and the second conductive layer having low reactivity with oxygen can be improved on the surface. The deterioration of the first extraction electrode due to oxidation can be suppressed by providing the above. That is, the reliability of the crystal vibrating element can be improved.

The first adhesive layer 151 and the second adhesive layer 155 may each be made of a metal material containing chromium, and the first conductive layer and the second conductive layer may be made of a metal material containing gold, respectively. According to this, Cr has higher adhesion to quartz than Au, and Au has higher conductivity and higher chemical stability than Cr. Therefore, the above-mentioned effect can be obtained.

The steps of providing the first extraction electrode 115a include a step of providing a metal film 155 and 156, a step of providing a photoresist 161 covering the metal film 155 and 156, and a step of patterning the photoresist 161 into the shape of the first extraction electrode 115a. And the step of etching the metal films 155 and 156 may be included. According to this, as compared with the case where the first excitation electrode and the first extraction electrode are formed in the same process by the photolithography method, the required accuracy of patterning is low, so that the manufacturing cost can be suppressed.

The steps of providing the first extraction electrode include a step of providing a first metal film and a second metal film so as to cover the first metal film on the first main surface side of the crystal piece, and a photo covering the second metal film. A step of providing a resist, a step of patterning the photoresist in the shape of the first extraction electrode, a step of etching the second metal film with a first etching solution so as to expose the first metal film, and a first step. It may include a step of etching the first metal film using a second etching solution having an etching rate different from that of the etching solution. According to this, when the outer shape of the first extraction electrode is formed by wet etching, the damage given to the first excitation electrode can be reduced, so that the manufacturing error of the frequency characteristic of the crystal vibrating element can be suppressed.

The steps of providing the first extraction electrode 115a include a step of arranging a sputtering mask in which the shape of the first extraction electrode 115a is patterned on the first main surface 111a side of the crystal piece 111, and a process of passing the metal films 155 and 156 through the sputtering mask. It may include a step of sputtering. According to this, the number of steps can be reduced as compared with the case where the outer shape of the first extraction electrode is formed by the photolithography method.

A step of reducing the thickness of the electrodes 114a and 115a provided in the central portion 117 to adjust the frequency may be further included. According to this, the manufacturing error of the frequency characteristic of the crystal vibrating element can be suppressed.

Of the second main surface 111b of the crystal piece 111, the step of providing the second excitation electrode 114b facing the first excitation electrode 114a at the central portion 117 and the second excitation electrode 114b as a metal mask for protecting the central portion 117 are used. A step of removing a part of the peripheral portions 118 and 119 to form the second side surfaces 112b and 113b between the central portion 117 and the peripheral portion 118 on the second main surface 111b side of the crystal piece 111, and as a metal mask. A step of providing a second extraction electrode 115b extending to the peripheral edge 118 on the second main surface 111b side of the crystal piece 111 so as to come into contact with the second excitation electrode 114b used may be further included. According to this, the same effect as described above can be obtained.

According to another aspect of the present invention, it has a first main surface 11a and a second main surface 11b facing the first main surface 11a, and is located on the central side when the first main surface 11a is viewed in a plan view. It has a central portion 17 and peripheral portions 18 and 19 located outside the central portion 17, and the central portion 17 and the peripheral edge portion 18 are provided on at least the first main surface 11a side of the first main surface 11a and the second main surface 11b. The crystal piece 11 having the first side surfaces 12a and 13a formed between the parts and 19 and the first excitation electrode 14a provided in the central portion 17 of the first main surface 11a of the crystal piece 11 and the crystal piece. Of the second main surface 11b of 11, the second excitation electrode 14b provided in the central portion 17 and facing the first excitation electrode 14a, and the first extraction electrode 15a electrically connected to the first excitation electrode 14a. A second extraction electrode 15b electrically connected to the second excitation electrode 14b is provided, and at least the first extraction electrode 15a is a first excitation electrode when the first main surface 11a of the crystal piece 11 is viewed in a plan view. Provided is a crystal vibrating element 10 that covers at least a portion of 14a and extends from a central portion 17 to a peripheral portion 18.

According to the above aspect, by forming the first excitation electrode up to the edge of the first main surface in the central portion, that is, the boundary with the first side surface in the central portion, the utilization efficiency of the region contributing to excitation in the central portion is improved. However, the crystal vibrating element can be miniaturized. In addition, the confinement efficiency of the vibration excited in the central portion can be improved. Since the first extraction electrode covers a part of the first excitation electrode, the contact area between the first excitation electrode and the first extraction electrode increases, and the electrical connection between the first excitation electrode and the first extraction electrode is established. Stabilize. In addition, damage to the first excitation electrode can be suppressed, and deterioration of the frequency characteristics of the crystal vibrating element can be suppressed.

When the first main surface 11a of the crystal piece 11 is viewed in a plan view, the outer edge of the first excitation electrode 14a may extend to the boundary with the first side surface 12a in the central portion 17. According to this, since the shape of the first main surface of the central portion and the shape of the first excitation electrode match, the fluctuation of the shape of the first excitation electrode can be suppressed, and the fluctuation of the frequency characteristic of the crystal vibrating element can be suppressed.

The first excitation electrode 14a has a higher conductivity than the first contact layer 51 provided on the first main surface 11a side of the crystal piece 11 and the first contact layer 51, and is the first of the crystal pieces 11. A first conductive layer 52 that covers the first adhesive layer 51 when the main surface 11a is viewed in a plan view may be provided. According to this, by providing the first adhesion layer having high reactivity with oxygen on the base, the adhesion between the crystal piece and the first excitation electrode can be improved, and the first conductive layer having low reactivity with oxygen can be improved on the surface. The deterioration of the first excitation electrode due to oxidation can be suppressed by providing the above. That is, the reliability of the crystal vibrating element can be improved.

The first extraction electrode 15a has a second contact layer 55 provided on the first main surface 11a side of the crystal piece 11 and a higher conductivity than the second contact layer 55, and is the first of the crystal pieces 11. A second conductive layer 56 that covers the second adhesive layer 55 when the main surface 11a is viewed in a plan view may be provided. According to this, by providing the second adhesion layer having high reactivity with oxygen on the base, the adhesion between the crystal piece and the first extraction electrode can be improved, and the second conductive layer having low reactivity with oxygen can be improved on the surface. The deterioration of the first extraction electrode due to oxidation can be suppressed by providing the above. That is, the reliability of the crystal vibrating element can be improved.

The first adhesive layer 51 and the second adhesive layer 55 may each be made of a metal material containing chromium, and the first conductive layer 52 and the second conductive layer 56 may be made of a metal material containing gold, respectively. According to this, Cr has higher adhesion to quartz than Au, and Au has higher conductivity and higher chemical stability than Cr. Therefore, the above-mentioned effect can be obtained.

The thickness T3 of the portion provided at the central portion 17 of the first extraction electrode 15a may be smaller than the thickness T4 of the portion provided at the peripheral portion 18 of the first extraction electrode 15a. According to this, the frequency characteristic of the crystal vibrating element can be adjusted by scraping the surface of the electrode provided in the central portion. Therefore, the manufacturing error of the frequency characteristic of the crystal vibrating element can be suppressed.

The thickness of the central portion 17 is larger than the thickness of the peripheral portions 18 and 19, and the first side surfaces 12a and 13a may connect the central portion 17 and the peripheral portions 18 and 19. According to this, the above-mentioned effect can be obtained in the step formed by the so-called forward mesa type structure.

The thickness of the central portion 217 is smaller than the thickness of the peripheral portions 218 and 219, and the first side surfaces 212a and 213a may connect the central portion 217 and the peripheral portions 218 and 219. According to this, the above-mentioned effect can be obtained in the step formed by the so-called inverted mesa type structure.

The crystal piece 11 has second side surfaces 12b and 13b formed between the central portion 17 and the peripheral portions 18 and 19 on the second main surface 11b side, and the second extraction electrode 15b is the second lead electrode of the crystal piece 11. Even if it covers at least a part of the second excitation electrode 14b when the main surface 11b is viewed in a plan view and extends from the central portion 17 to the peripheral portion 18 on the second main surface 11b side of the crystal piece 11. Good. According to this, the same effect as described above can be obtained.

The crystal piece 911 may have a slit formed between the central portion 917 and the peripheral portion 919. Even in such a configuration, the above-mentioned effect can be obtained.

As described above, according to one aspect of the present invention, it is possible to provide a crystal vibration element capable of reducing a manufacturing error of vibration characteristics and a manufacturing method thereof.

It should be noted that the embodiments described above are for facilitating the understanding of the present invention, and are not for limiting and interpreting the present invention. The present invention can be modified / improved without departing from the spirit thereof, and the present invention also includes an equivalent thereof. That is, those skilled in the art with appropriate design changes to each embodiment are also included in the scope of the present invention as long as they have the features of the present invention. For example, each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those exemplified, and can be changed as appropriate. In addition, the elements included in each embodiment can be combined as much as technically possible, and the combination thereof is also included in the scope of the present invention as long as the features of the present invention are included.

1 ... Crystal oscillator 10 ... Crystal vibrating element 11 ... Crystal piece 17 ... Central part 18, 19 ... Peripheral part 11a, 17a, 18a, 19a ... First main surface 11b, 17b, 18b, 19b ... Second main surface 12a, 13a ... 1st side surface 12b, 13b ... 2nd side surface 14a ... 1st excitation electrode 14b ... 2nd excitation electrode 15a ... 1st extraction electrode 15b ... 2nd extraction electrode 51, 53 ... 1st adhesion layer 52, 54 ... 1st Conductive layer 55 ... Second adhesive layer 56 ... Second conductive layer

Claims (21)

It has a first main surface and a second main surface facing the first main surface, and a central portion located on the central side when the first main surface is viewed in a plan view and a peripheral portion located on the outer side of the central portion. And the process of preparing a crystal piece,
A step of providing a first excitation electrode in the central portion of the first main surface of the crystal piece, and
While using the first excitation electrode as a metal mask to protect the central portion, a part of the peripheral portion is removed, and a second portion is formed between the central portion and the peripheral portion on the first main surface side of the crystal piece. 1 The process of forming one side and
A step of providing a first extraction electrode extending to the peripheral portion on the first main surface side of the crystal piece so as to come into contact with the first excitation electrode used as the metal mask.
Only including,
A method for manufacturing a crystal vibrating element , wherein the thickness of a portion provided in the central portion of the first extraction electrode is smaller than the thickness of a portion provided in the peripheral portion of the first extraction electrode. It has a first main surface and a second main surface facing the first main surface, and a central portion located on the central side when the first main surface is viewed in a plan view and a peripheral portion located on the outer side of the central portion. And the process of preparing a crystal piece,
A step of providing a first excitation electrode in the central portion of the first main surface of the crystal piece, and
While using the first excitation electrode as a metal mask to protect the central portion, a part of the peripheral portion is removed, and a second portion is formed between the central portion and the peripheral portion on the first main surface side of the crystal piece. 1 The process of forming one side and
A step of providing a first extraction electrode extending to the peripheral portion on the first main surface side of the crystal piece so as to come into contact with the first excitation electrode used as the metal mask.
Including
The thickness of the central portion is smaller than the thickness of the peripheral portion.
The first side surface is a method for manufacturing a crystal vibrating element, which connects the central portion and the peripheral portion. The first extraction electrode passes through the first side surface.
The method for manufacturing a crystal vibrating element according to claim 1 or 2. The first extraction electrode covers at least a part of the first excitation electrode at the central portion when the first main surface of the crystal piece is viewed in a plan view.
The method for manufacturing a crystal vibrating element according to any one of claims 1 to 3. The step of providing the first excitation electrode is
A step of providing a first adhesion layer on the first main surface side of the quartz piece, and
It has higher conductivity than the first adhesive layer, and includes a step of providing a first conductive layer that covers the first adhesive layer when the first main surface of the quartz piece is viewed in a plan view.
The method for manufacturing a crystal vibrating element according to any one of claims 1 to 4. The step of providing the first extraction electrode is
A step of providing a second adhesion layer on the first main surface side of the quartz piece, and
It has higher conductivity than the second adhesive layer, and includes a step of providing a second conductive layer that covers the second adhesive layer when the first main surface of the quartz piece is viewed in a plan view.
The method for manufacturing a crystal vibrating element according to claim 5. The first adhesive layer and the second adhesive layer are each made of a metal material containing chromium, and the first conductive layer and the second conductive layer are each made of a metal material containing gold.
The method for manufacturing a crystal vibrating element according to claim 6. The step of providing the first extraction electrode is
The process of providing a metal film and
A step of providing a photoresist covering the metal film and
A step of patterning the photoresist into the shape of the first extraction electrode, and
Including the step of etching the metal film.
The method for manufacturing a crystal vibrating element according to any one of claims 1 to 7. The step of providing the first extraction electrode is
A step of providing a first metal film and a second metal film so as to cover the first metal film on the first main surface side of the crystal piece.
A step of providing a photoresist covering the second metal film and
A step of patterning the photoresist into the shape of the first extraction electrode, and
A step of etching the second metal film with a first etching solution so as to expose the first metal film, and a step of etching the second metal film.
This includes a step of etching the first metal film using a second etching solution having an etching rate different from that of the first etching solution.
The method for manufacturing a crystal vibrating element according to any one of claims 1 to 7. The step of providing the first extraction electrode is
A step of arranging a sputtering mask in which the shape of the first extraction electrode is patterned on the first main surface side of the crystal piece, and
A step of sputtering a metal film through the sputter mask.
The method for manufacturing a crystal vibrating element according to any one of claims 1 to 7. A step of adjusting the frequency by reducing the thickness of the electrode provided in the central portion is further included.
The method for manufacturing a crystal vibrating element according to any one of claims 1 to 10. A step of providing a second excitation electrode facing the first excitation electrode in the central portion of the second main surface of the crystal piece, and a step of providing the second excitation electrode.
While using the second excitation electrode as a metal mask to protect the central portion, a part of the peripheral portion is removed, and a second portion is formed between the central portion and the peripheral portion on the second main surface side of the crystal piece. The process of forming two sides and
A step of providing a second extraction electrode extending to the peripheral portion on the second main surface side of the crystal piece so as to come into contact with the second excitation electrode used as the metal mask.
Including,
The method for manufacturing a crystal vibrating element according to any one of claims 1 to 11. It has a first main surface and a second main surface facing the first main surface, and a central portion located on the central side when the first main surface is viewed in a plan view and a peripheral portion located outside the central portion. A crystal piece having the above and having a first side surface formed between the central portion and the peripheral portion on at least the first main surface side of the first main surface and the second main surface.
Of the first main surface of the quartz piece, the first excitation electrode provided in the central portion and the first excitation electrode.
A second excitation electrode provided in the central portion of the second main surface of the quartz piece and facing the first excitation electrode, and a second excitation electrode.
The first extraction electrode electrically connected to the first excitation electrode and
The second extraction electrode electrically connected to the second excitation electrode and
With
At least the first lead electrode, said covers at least a portion of the first excitation electrode when the first major surface of the crystal piece in plan view, extend over the peripheral portion from the central portion ,
A crystal vibrating element in which the thickness of a portion of the first extraction electrode provided at the central portion is smaller than the thickness of a portion of the first extraction electrode provided at the peripheral portion. It has a first main surface and a second main surface facing the first main surface, and a central portion located on the central side when the first main surface is viewed in a plan view and a peripheral portion located outside the central portion. A crystal piece having the above and having a first side surface formed between the central portion and the peripheral portion on at least the first main surface side of the first main surface and the second main surface.
Of the first main surface of the quartz piece, the first excitation electrode provided in the central portion and the first excitation electrode.
A second excitation electrode provided in the central portion of the second main surface of the quartz piece and facing the first excitation electrode, and a second excitation electrode.
The first extraction electrode electrically connected to the first excitation electrode and
The second extraction electrode electrically connected to the second excitation electrode and
With
At least the first extraction electrode covers at least a part of the first excitation electrode when the first main surface of the crystal piece is viewed in a plan view, and extends from the central portion to the peripheral portion. ,
The thickness of the central portion is smaller than the thickness of the peripheral portion.
The first side surface is a crystal vibrating element that connects the central portion and the peripheral portion. When the first main surface of the crystal piece is viewed in a plan view, the outer edge of the first excitation electrode extends to the boundary with the first side surface in the central portion.
The crystal vibrating element according to claim 13 or 14. The first excitation electrode is
With the first adhesion layer provided on the first main surface side of the quartz piece,
It has higher conductivity than the first adhesive layer, and includes a first conductive layer that covers the first adhesive layer when the first main surface of the quartz piece is viewed in a plan view.
The crystal vibrating element according to any one of claims 13 to 15. The first extraction electrode is
A second adhesion layer provided on the first main surface side of the quartz piece, and
It has higher conductivity than the second adhesive layer, and includes a second conductive layer that covers the second adhesive layer when the first main surface of the quartz piece is viewed in a plan view.
The crystal vibrating element according to claim 16. The first adhesive layer and the second adhesive layer are each made of a metal material containing chromium, and the first conductive layer and the second conductive layer are each made of a metal material containing gold.
The crystal vibrating element according to claim 17. The thickness of the central portion is larger than the thickness of the peripheral portion.
The first side surface connects the central portion and the peripheral portion.
The crystal vibrating element according to any one of claims 13 to 18. The crystal piece has a second side surface formed between the central portion and the peripheral portion on the second main surface side.
The second extraction electrode covers at least a part of the second excitation electrode when the second main surface of the crystal piece is viewed in a plan view, and the central portion of the crystal piece on the second main surface side. Extends from to the peripheral portion,
The crystal vibrating element according to any one of claims 13 to 19. The crystal piece has a slit formed between the central portion and the peripheral portion.
The crystal vibrating element according to any one of claims 13 to 20.

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