TW201931766A - Crystal oscillator element and method for producing same - Google Patents

Abstract

This method for producing a crystal oscillator element (10) comprises: a step for preparing a crystal piece (111); a step for providing a central part (117) of the crystal piece (111) with a first excitation electrode (114a); a step for forming a first lateral surface (112a) between the central part (117) and a peripheral part (118) of the crystal piece (111) by removing a part of the peripheral part (118), while using the first excitation electrode (114a) as a metal mask that protects the central part (117); and a step for providing a first lead-out electrode (115a), which extends in the peripheral part (118) of the crystal piece (111), so that the first lead-out electrode is in contact with the first excitation electrode (114a).

Description

   Crystal vibration element and manufacturing method thereof   

The invention relates to a crystal vibration element and a manufacturing method thereof.

The piezoelectric vibrator is mounted on a mobile communication device or the like, and is used as a timing device or a load sensor, for example. In particular, a crystal oscillator, which is a type of piezoelectric vibrator, uses artificial crystal for piezoelectric bodies, and has high frequency accuracy. The crystal vibrating element mounted on the crystal oscillator is formed by, for example, the following method: by etching using a photolithography technique, the shape of the crystal wafer is processed, and the crystal wafer is patterned to form various electrodes. In order to improve the accuracy of the etching process, various configurations are being studied.

For example, Patent Document 1 discloses a method for manufacturing a crystal vibrating element, which includes the steps of etching a water crystal with a photoresist and a corrosion-resistant film as a mask, and providing a stepped surface or an inclined surface; removing the photoresist and corrosion resistance A film step; and a step of etching a metal film using a photoresist as a mask to form an excitation electrode, a lead-out electrode, and the like.

[Prior technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-283660

However, in the case where a stepped surface or an inclined surface is formed on the crystal wafer, and the main surface of the crystal wafer is formed into an uneven shape, if a photoresist is formed after the outer shape is formed, the photoresist is caused by surface tension and the like. The film thickness becomes smaller at the corners of the main surface of the crystal piece. Due to the variation in the film thickness of such a photoresist, there is a problem that, for example, the processing accuracy of the excitation electrode is reduced.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a crystal vibrating element and a method for manufacturing the same that can reduce manufacturing errors of vibration characteristics.

A method for manufacturing a crystal vibrating element according to an aspect of the present invention includes a step of preparing a crystal wafer having a first main surface and a second main surface facing the first main surface, and having a first main surface in plan view. The central part is located on the central side and the peripheral part on the outer side of the central part; in the first main surface of the crystal chip, a step of setting a first excitation electrode in the center; while using the first excitation electrode as a metal shield to protect the center A step of forming a first side surface between the central portion and the peripheral edge portion on the first main surface side of the crystalline wafer while removing a part of the peripheral edge portion; in contact with the first excitation electrode used as a metal shield, On the side of the first main surface of the quartz chip, a step of providing a first lead-out electrode extending to the peripheral portion is provided.

A crystal vibration element according to another aspect of the present invention includes a crystal chip having a first main surface and a second main surface facing the first main surface, and having a central portion located on the center side when the first main surface is viewed in plan. And a peripheral edge portion located on the outer side of the central portion, at least one of the first principal surface and the second principal surface is formed on the first principal surface side, and a first lateral surface is formed between the central portion and the peripheral edge portion; The first main surface is provided at the central portion; the second excitation electrode is provided at the central portion of the second main surface of the quartz chip and is opposed to the first excitation electrode; the first lead-out electrode is electrically connected to A first excitation electrode; and a second extraction electrode that is electrically connected to the second excitation electrode; and the first extraction electrode covers at least a portion of the first excitation electrode when viewed from the first main surface of the crystal chip, and extends from the central portion To the periphery.

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

1‧‧‧ crystal oscillator

10‧‧‧ Crystal Vibration Element

11‧‧‧Crystal

17‧‧‧ Central

18, 19‧‧‧ Peripheral

11a, 17a, 18a, 19a

11b, 17b, 18b, 19b ‧‧‧ 2nd main face

12a, 13a‧‧‧1st side

12b, 13b‧‧‧ 2nd side

14a‧‧‧The first excitation electrode

14b‧‧‧Second excitation electrode

15a‧‧‧The first extraction electrode

15b‧‧‧Second extraction electrode

51, 53‧‧‧ the first tight layer

52, 54‧‧‧ the first conductive layer

55‧‧‧Second Adhesive Layer

56‧‧‧ 2nd conductive layer

FIG. 1 is an exploded perspective view schematically showing the configuration of the crystal oscillator of the first embodiment.

FIG. 2 is a cross-sectional view schematically showing a configuration of a cross section taken along the line II-II of the crystal oscillator shown in FIG. 1. FIG.

FIG. 3 is a cross-sectional view schematically showing a configuration of the crystal resonator element shown in FIG. 2.

FIG. 4 is a flowchart schematically showing a part of a method for manufacturing a crystal resonator element according to the first embodiment.

FIG. 5 is a flowchart schematically showing a method of manufacturing the crystal resonator element according to the first embodiment following the flowchart shown in FIG. 4.

FIG. 6 is a cross-sectional view schematically showing a step of etching a quartz wafer.

FIG. 7 is a cross-sectional view schematically showing a step of providing a second adhesion layer and a 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 adhesion layer and the second conductive layer.

Fig. 10 is a cross-sectional view schematically showing a step of cutting an electrode surface in a central portion.

Fig. 11 is a cross-sectional view schematically showing the configuration of a crystal oscillator according to a second embodiment.

Fig. 12 is an exploded perspective view schematically showing a configuration of a crystal oscillator according to a third embodiment.

Fig. 13 is a cross-sectional view schematically showing a configuration of a crystal oscillator according to a third embodiment.

Fig. 14 is a perspective view schematically showing a configuration of a crystal resonator element according to a fourth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, after the second embodiment, the same or similar constituent elements as those in the first embodiment are denoted by the same or similar symbols as those in the first embodiment, and detailed descriptions are appropriately omitted. The effects obtained in the second and subsequent embodiments are the same as those in the first embodiment, and descriptions thereof are appropriately omitted. The drawings of the embodiments are examples, and the dimensions or shapes of the parts are schematic, and the technical scope of the invention of the present invention should not be construed as the embodiments.

<First Embodiment>

First, the structure 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 of the first embodiment. FIG. 2 is a cross-sectional view schematically showing a configuration of a cross section taken along the line II-II of the crystal oscillator shown in FIG. 1. FIG. FIG. 3 is a cross-sectional view schematically showing a configuration of the crystal resonator element shown in FIG. 2. The first direction D1, the second direction D2, and the third direction D3 shown in the figure are directions orthogonal to each other. The first direction D1, the second direction D2, and the third direction D3 may be directions crossing each other at an angle other than 90 °. The first direction D1, the second direction D2, and the third direction D3 are not limited to the direction of the arrow (positive direction) shown in FIG. 1, and include the direction opposite to the arrow (negative direction).

Quartz Crystal Resonator Unit 1 is a type of Piezoelctric Resonator Unit, which excites the Quartz Crystal Resonator 10 in response to a voltage applied. The quartz-crystal vibrating element 10 uses a Quartz Crystal Element 11 as a piezoelectric body that vibrates according to an applied voltage.

As shown in FIG. 1, the crystal resonator 1 includes a crystal resonator element 10, a cover member 20, a base member 30, and a bonding member 40. The base member 30 and the cover member 20 are holders for receiving the crystal vibration element 10. In the example shown here, the cover member 20 has a concave shape, specifically, a box shape with an opening, and the base member 30 has a flat plate shape. The shapes of the cover 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 cover member and the base member may have a concave shape having openings on the sides facing each other.

The quartz-crystal vibrating element 10 includes a thin-shaped quartz crystal 11. The quartz crystal 11 has a first main surface 11a and a second main surface 11b which face each other. The first main surface 11 a is located on the side opposite to the side facing the base member 30, and the second main surface 11 b is located on the side facing the base member 30.

The quartz crystal 11 is, for example, an AT-cut quartz crystal. The main surface of the AT-cut crystal is a plane parallel to a plane specified by the X axis and the Z 'axis (hereinafter referred to as "XZ' plane". The same applies to a plane specified by other axes or other directions). Therefore, the first principal surface 11 a and the second principal surface 11 b of the quartz crystal 11 correspond to the XZ ′ plane, respectively. The AT-cut quartz crystal is formed by, for example, subjecting a crystal substrate obtained by cutting and polishing a synthetic Quartz Crystal ingot to an etching process. Furthermore, the X-axis, Y-axis, and Z-axis are Crystallographic Axes. The X-axis corresponds to an electrical axis, the Y-axis corresponds to a mechanical axis, and the Z-axis corresponds to an optical axis. The Y 'axis and the Z' axis are axes obtained by rotating the Y axis and the Z axis from the Y axis toward the Z axis by 35 degrees, 15 minutes, and 1 minute and 30 seconds, respectively. In addition, the cutting angle of the crystal wafer can also be applied to cutting other than AT cutting (such as BT cutting).

The AT-cut crystal wafer 11 has a long side direction extending along a long side parallel to the X-axis direction, a short side direction extending along a short side parallel to the Z'-axis direction, and a thickness direction extending along a thickness parallel to the Y'-axis direction. The quartz plate 11 has a rectangular shape in plan view of the first main surface 11a, and includes a central portion 17 located in the center and contributing to excitation, a peripheral portion 18 adjacent to the central portion 17 on the negative side of the X axis, and a portion on the X axis. A peripheral portion 19 adjacent to the central portion 17 on the front side. The central portion 17 and the peripheral portions 18 and 19 are respectively provided in a strip shape along the Z ′ axis direction, and extend from one end of the crystal wafer 11 opposite to the Z ′ axis direction to the other end. Therefore, the first principal surface 11 a of the quartz crystal 11 includes the first principal surface 17 a of the central portion 17, the first principal surface 18 a of the peripheral portion 18, and the first principal surface 19 a of the peripheral portion 19. Similarly, the second main surface 11 b of the quartz crystal 11 includes the second main surface 17 b of the central portion 17, the second main surface 18 b of the peripheral portion 18, and the second main surface 19 b of the peripheral portion 19.

The quartz crystal 11 has a mesa structure in which the central portion 17 is thicker than the peripheral portions 18 and 19. Specifically, a first main surface 17a connecting the central portion 17 and a first side surface 12a connecting the first main surface 18a of the peripheral portion 18 is formed between the central portion 17 and the peripheral portion 18, and a second main portion connecting the central portion 17 The surface 17 b and the second side surface 12 b of the second main surface 18 b of the peripheral edge portion 18. Similarly, a step is formed between the central portion 17 and the peripheral portion 19, and a first main surface 17a connecting the central portion 17 and a first side surface 13a of the first main surface 19a of the peripheral portion 19 are formed to connect the central portion 17 The second main surface 17 b and the second side surface 13 b of the second main surface 19 b of the peripheral portion 19. In this way, the first principal surface 11 a and the second principal surface 11 b of the quartz crystal 11 form a step between the central portion 17 and the peripheral portion 18 and between the central portion 17 and the peripheral portion 19, respectively.

The first side surfaces 12 a and 13 a and the second side surfaces 12 b and 13 b of the crystal piece 11 extend in directions orthogonal to the first main surface 11 a and the second main surface 11 b 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 faces 12a, 13a and the second side faces 12b, 13b of the quartz crystal 11 may be formed in a tapered shape, respectively. For example, the first side surface 12a and the second side surface 13b may extend in a direction inclined from the positive direction of the Y 'axis toward the positive direction of the X axis, and the second side surface 12b and the first side surface 13a may also extend toward the X direction from the positive direction of the Y' axis. The axis extends in a negative direction. In the example shown in FIG. 1, although the step is formed between the central portion 17 and the peripheral portions 18 and 19 and the step difference is formed on both the first main surface 11 a side and the second main surface 11 b side, As a modification, the step may be formed only on either the first main surface 11a side or the second main surface 11b side.

The quartz crystal 11 is not limited to the above as long as it has a shape in which a side surface is formed between a central portion and a peripheral portion. For example, the quartz crystal 11 may be provided with a peripheral portion adjacent to the central portion 17 in the positive or negative direction of the Z ′ axis. In addition, the quartz crystal 11 is not limited to a mesa-type structure, and may be a inverted mesa-type structure in which the central portion 17 is thinner than the peripheral portions 18 and 19. The thickness change of the central portion 17 and the peripheral edge portions 18 and 19 may be a convex shape or an inclined surface shape that continuously changes. As described below, a slit may be formed between the central portion and the peripheral portion. In addition, the shape of the quartz crystal 11 is not limited to a plate shape. For example, when the first main surface 11a is viewed in plan, it may be a comb-tooth type having a pair of parallel arm portions and a connection portion connecting the two arm portions.

In the examples shown in FIGS. 1 and 2, the crystal vibrating element 10 is set such that the X axis is parallel to the first direction D1, the Z ′ axis is parallel to the second direction D2, and the Y ′ axis is parallel to the third direction D3.

The crystal resonator element 10 includes a first excitation electrode 14 a and a second excitation electrode 14 b constituting a pair of electrodes. The first excitation electrode 14 a is provided on the first main surface 17 a of the central portion 17. The second excitation electrode 14 b is provided on the second main surface 17 b of the central portion 17. The first excitation electrode 14 a and the second excitation electrode 14 b face each other in the third direction D3 via the crystal wafer 11. The first excitation electrode 14a and the second excitation electrode 14b are arranged so as to substantially overlap with each other 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 plan, the outer edge of the first excitation electrode 14a extends to the boundary between the central portion 17 and the first side surface 12a. When the second main surface 17b in the central portion 17 is viewed in plan, the outer edge of the second excitation electrode 14b extends to the boundary between the central portion 17 and the second side surface 12b. In other words, the outer shape of the main surface of the first excitation electrode 14 a facing the central portion 17 coincides with the outer shape of the first main surface 17 a of the central portion 17. The outer shape of the main surface of the second excitation electrode 14 b facing the central portion 17 is the same as the outer shape of the second main surface 17 b of the central portion 17. Accordingly, the utilization efficiency of the central portion 17 that contributes to the excitation can be improved, and the crystal vibration element 10 can be miniaturized. In addition, the sealing efficiency of the excited vibration in the central portion 17 can be improved.

The crystal resonator element 10 includes a pair of first extraction electrodes 15a and a second extraction electrode 15b, and a pair of first connection electrodes 16a and second connection electrodes 16b. The first connection electrode 16a is electrically connected to the first excitation electrode 14a through the first extraction electrode 15a. The second connection electrode 16b is electrically connected to the second excitation electrode 14b through 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 lead-out electrode 15 a covers a part of the first excitation electrode 14 a when the first main surface 11 a of the crystal wafer 11 is viewed in plan, and extends from the central portion 17 through the first side surface 12 a to the peripheral portion 18 on the first main surface 11 a. The first lead-out electrode 15a is further drawn around the first main surface 18a of the peripheral portion 18 until it reaches the second main surface 18b. When the second main surface 11b of the crystal wafer 11 is viewed in plan, the second extraction electrode 15b covers a part of the second excitation electrode 14b, and the second main surface 11b extends from the central portion 17 through the second side surface 12b to the peripheral portion 18. Since the first lead-out electrode 15a covers at least a part of the first lead-out electrode 14a, the contact area between the first lead-out electrode 14a and the first lead-out electrode 15a increases, and the electrical connection is stable. In addition, since damage such as electrode peeling is likely to occur at the corner portion of the crystal wafer 11, by covering the end portion of the first excitation electrode 14a with the first extraction electrode 15a, damage to the first excitation electrode 14a can be suppressed. Therefore, deterioration of the frequency characteristics of the crystal resonator element 10 can be suppressed.

In addition, 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 wafer 11 is viewed in plan. In addition, when the first main surface 11a of the crystal wafer 11 is viewed in plan, the first extraction electrode 15a may cover the entire first excitation electrode 14a. Similarly, when the second main surface 11b of the crystal wafer 11 is viewed from the top, the second extraction electrode 15b may be adjacent to the second excitation electrode 14b, or may cover the entirety of the second excitation electrode 14b.

The first connection electrode 16 a is provided on the second main surface 18 b of the peripheral portion 18, and the second connection electrode 16 b is provided on the second main surface 18 b of the peripheral 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 various electrodes has a multilayer structure. The first excitation electrode 14 a includes a first adhesion layer 51 and a first conductive layer 52. The first adhesion layer 51 has higher adhesion to the quartz crystal 11 than the first conductive layer 52. The first adhesion layer 51 is provided on the first main surface 11 a side of the quartz crystal 11 and is in contact with the first main surface 17 a of the central portion 17. The first conductive layer 52 has higher conductivity than the first adhesion layer 51 and has higher chemical stability than the first adhesion layer 51. When the first main surface 11 a of the crystal wafer 11 is viewed in plan, the first conductive layer 52 covers the first adhesion layer 51. Similarly, the second excitation electrode 14 b includes a first adhesive layer 53 which is provided on the second main surface 11 b side of the quartz plate 11 and is in contact with the second main surface 17 b of the central portion 17. The surface 11 b covers the first conductive layer 54 of the first adhesion layer 53. However, the first excitation electrode 14a and the second excitation electrode 14b are not limited to a two-layer structure, and may be a single-layer structure or a multilayer structure having three or more layers.

The first extraction electrode 15 a includes a second adhesion layer 55 and a second conductive layer 56. The second adhesion layer 55 has higher adhesion to the quartz crystal 11 than the second conductive layer 56. The second adhesion layer 55 is provided on the first main surface 11 a side of the quartz chip 11, and is in contact with the first main surface 17 a and the second main surface 17 b of the central portion 17. The second adhesion layer 55 is also in contact with 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 adhesion layer 55 and has higher chemical stability than the second adhesion layer 55. When the first principal surface 11 a and the second principal surface 11 b of the quartz crystal 11 are viewed in plan, the second conductive layer 56 covers the second adhesion layer 55. That is, the area electrode in which the first lead-out electrode 15a and the first excitation electrode 14a at the central portion 17 overlap has a four-layer structure, the first conductive layer 52 covers the first contact layer 51, and the second contact layer 55 covers the first contact. The layer 52 and the second conductive layer 56 cover the second adhesion layer 55.

In addition, since the first connection electrode 16a is formed integrally with the first extraction electrode 15a, the second connection layer 55 and the second conductive layer 56 are provided in the same manner as the first extraction electrode 15a. Although not shown in FIG. 3, the second extraction electrode 15 b and the second connection electrode 16 b also include a second adhesion layer and a second conductive layer in the same manner. However, the first lead-out electrode 15a, the second lead-out electrode 15b, the first connection electrode 16a, and the second connection electrode 16b are not limited to a two-layer structure, and may be a single-layer structure or a multilayer structure of three or more layers.

The first adhesion layer 51 of the first excitation electrode 14a, the first adhesion layer 53 of the second excitation electrode 14b, and the second adhesion 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). The chromium (Cr) layer with a higher reactivity with oxygen is increased by the substrate to improve the adhesion between the crystal chip and the electrode, and the gold (Au) layer with a lower reactivity with oxygen is provided by the surface, which is caused by oxidation The deterioration of the electrodes is suppressed. Thereby, the reliability of the crystal vibration 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 referred to as "thickness") T1, which is greater than that of the first excitation electrode 14a. The thickness T2 of the portion where the first lead-out electrode 15a overlaps is small (T1 <T2). The thickness T3 of the portion of the first extraction electrode 15a provided at the central portion 17 is smaller than the thickness T4 of the portion of the first extraction electrode 15a provided at the peripheral portion 18 (T3 <T4). The thickness of the first excitation electrode 14a is smaller than the thickness T1 of the first excitation electrode 14a, and the thickness of the first adhesive layer 51 is equal to the thickness of the first conductive layer 52. The thickness of the portion T3 of the first lead-out electrode 15a is equal to the thickness of the portion T4, and the thickness of the second adhesion layer 55 is equal to the thickness of the second conductive layer 56. In this way, the thickness of the electrode can be adjusted by cutting the surface of the electrode provided on the central portion 17, so that the frequency characteristics of the crystal vibration element 10 can be adjusted.

Although in the configuration example shown in FIG. 3, the thickness of the electrode provided on the central portion 17 is smaller than that of the entire portion facing the first main surface 17 a of the central portion 17, it is at least less than the first main portion of the central portion 17. The thickness of the portion facing the central portion of the surface 17a may be reduced. Moreover, it is not necessary to cut the surface of the electrode provided in the central portion 17, and the thickness T1 and thickness T2 of the first excitation electrode 14a may be equal, and the thickness T3 and thickness T4 of the first extraction electrode 15a may be equal.

The cover member 20 has a concave shape and has a box shape that opens toward the first main surface 32 a of the base member 30. The cover member 20 is joined to the base member 30 to provide an inner space 26 surrounded by the cover member 20 and the base member 30. The internal space 26 houses the crystal resonator element 10. The shape of the cover member 20 is not particularly limited as long as it can accommodate the crystal vibration element 10. In one example, the shape of the cover member 20 is rectangular when viewed from the top surface of the top surface portion 21. The cover 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 cover member 20 is not particularly limited, and is made of, for example, a conductive material such as metal. The cover member 20 is formed of a conductive material, and has an electromagnetic shielding function that shields at least a part of electromagnetic waves radiated to the internal space 26.

As shown in FIG. 2, the cover 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 cover member 20 includes a top surface portion 21 facing the first main surface 32 a of the base member 30, and a side wall portion 22 connected to the outer edge of the top surface portion 21 and extending in a direction crossing the main surface of the top surface portion 21. In addition, the cover member 20 includes a facing surface 23 facing the first main surface 32 a of the base member 30 at the concave opening end portion (the end portion of the side wall portion 22 that is close to the base member 30). The facing surface 23 extends in a frame shape so as to surround the periphery of the crystal vibration element 10.

The base member 30 holds the crystal vibration element 10 and enables it to excite. 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 thickness direction side parallel to the third direction D3.

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

The base member 30 includes 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 33 a and 33 b are terminals for electrically connecting the base member 30 and the crystal vibration element 10. The external electrodes 35a, 35b, 35c, and 35d are terminals for electrically connecting a circuit substrate (not shown) and the crystal oscillator 1 to each other. The electrode pad 33a is electrically connected to the external electrode 35a through a via electrode 34a extending in the third direction D3, and the electrode pad 33b is electrically connected to the external electrode 35b through a via electrode 34b extending in the third direction D3. The through-hole electrodes 34a and 34b are formed in guide holes that penetrate the base 31 in the third direction D3. The external electrodes 35c and 35d may also be dummy electrodes that do not input or output electric signals, etc., or may be ground electrodes that supply a ground potential to the cover member 20 to improve the electromagnetic shielding function of the cover member 20. The external electrodes 35c and 35d may be omitted.

The conductive holding members 36a and 36b electrically connect one pair of connection electrodes 16a and 16b of the crystal resonator element 10 to one pair of electrode pads 33a and 33b of the base member 30, respectively. In addition, the conductive holding members 36 a and 36 b hold the crystal resonator element 10 on the first main surface 32 a of the base member 30 and can excite the crystal resonator element 10. The conductive holding members 36a and 36b are made of, for example, a conductive adhesive containing a thermosetting resin or an ultraviolet curing resin containing an epoxy-based resin or a silicone-based resin as a main agent, and include a conductive material for imparting conductivity to the adhesive. Additives such as conductive particles. Further, a filler may be added to the adhesive for the purpose of increasing the strength or maintaining the distance between the base member and the crystal vibration element.

A sealing member 37 is provided on the first main surface 32 a 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 32 a is viewed in plan. When the first main surface 32 a is viewed in plan, the electrode pads 33 a and 33 b are arranged inside the sealing member 37, and the sealing member 37 is provided so as to surround the crystal resonator element 10. The sealing member 37 is made of a conductive material. For example, by constituting the sealing member 37 with the same material as the electrode pads 33a and 33b, the sealing member 37 may be provided at the same time as the step of providing the electrode pads 33a and 33b.

The bonding member 40 is provided on each of the entire periphery of the cover member 20 and the base member 30. Specifically, the bonding member 40 is provided on the sealing member 37 and has a rectangular frame shape. The sealing member 37 and the joint member 40 are separated between the facing surface 23 of the side wall portion 22 of the cover member 20 and the first main surface 32 a of the base member 30.

Both the cover member 20 and the base member 30 are joined by a sealing member 37 and a joint member 40, and the crystal resonator element 10 is sealed in an internal space (cavity) 26 surrounded by the cover member 20 and the base member 30. . In this case, the internal space 26 is preferably in a vacuum state where the air pressure is lower than the atmospheric pressure. As a result, it is possible to reduce the change with time of the frequency characteristics of the crystal oscillator 1 caused by the oxidation of the first excitation electrode 14a and the second excitation electrode 14b.

The crystal oscillator 1 applies an alternating electric field between the first excitation electrode 14 a and the second excitation electrode 14 b constituting the crystal resonator element 10 through the external electrodes 35 a and 35 b of the base member 30. Thereby, the crystal wafer 11 is vibrated in a specific vibration mode such as a thickness shear vibration mode, and a resonance characteristic accompanying the vibration is obtained.

Next, a manufacturing method of the crystal resonator 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 a method for manufacturing a crystal resonator element according to the first embodiment. FIG. 5 is a flowchart schematically showing a method of manufacturing the crystal resonator element according to the first embodiment following the flowchart shown in FIG. 4. FIG. 6 is a cross-sectional view schematically showing a step of etching a quartz wafer. FIG. 7 is a cross-sectional view schematically showing a step of providing a second adhesion layer and a 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 adhesion layer and the second conductive layer. Fig. 10 is a cross-sectional view schematically showing a step of cutting an electrode surface in a central portion.

First, a crystal wafer is prepared (S11). The crystal plate 111 is a flat plate-shaped member cut out from a single crystal of an artificial crystal so that the XZ ′ plane becomes the main plane. The surface of the crystal wafer 111 may be planarized by, for example, a polishing process such as chemical mechanical polishing. In a crystal vibration element having a thickness-shear vibration mode, the thickness of the crystal chip has a large effect on the frequency characteristics of the piezoelectric vibration element. Therefore, in order to achieve the target frequency characteristics, the thickness of the crystal wafer can also be adjusted by the polishing process in this step.

Next, a first adhesion layer is provided (S12). The first adhesion layers 151 and 153 are formed so as to cover the entire surface of each of the first principal surface 111 a and the second principal surface 111 b of the quartz crystal 111. The first adhesion layers 151 and 153 before patterning correspond to a series of metal films including one of the crystal wafers 111. The first adhesion layers 151 and 153 are formed, for example, by depositing a metal material containing chromium (Cr) on the surface of the crystal wafer 111 by sputtering. The first adhesion layers 151 and 153 are formed so as to have a thickness of 1 nm to 20 nm. When the thickness of the first adhesion layers 151 and 153 is 1 nm or more, it is possible to suppress a decrease in adhesion of the first excitation electrode 114a and the second excitation electrode 114b to the crystal wafer 111. This can reduce the occurrence of damage such as peeling of the first excitation electrode 114a and the second excitation electrode 114b. In addition, when the thickness of the first adhesion layers 151 and 153 is 20 nm or less, deterioration of the vibration characteristics of the crystal resonator element 110 can be suppressed.

Next, a first conductive layer is provided (S13). The first conductive layers 152 and 154 are formed on the first main surface 111a side and the second main surface 111b side of the crystal wafer 111 so as to cover the first adhesion layers 151 and 153, respectively. The first conductive layers 152 and 154 before patterning correspond to a series of metal films including one of the first adhesion layers 151 and 153 including the crystal wafer 111. The first conductive layers 152 and 154 are formed by depositing a metal material containing gold (Au) on the surfaces of the first adhesion layers 151 and 153, for example, by sputtering. The first conductive layers 152 and 154 are formed so as to have a thickness of 1 nm to 500 nm. When the thickness of the first conductive layers 152 and 154 is 1 nm or more, sufficient electrical conductivity is provided to the first excitation electrode 114a and the second excitation electrode 114b. In addition, it is possible to suppress oxidation of the first adhesive layers 151 and 153 corresponding to the susceptor. Therefore, deterioration of the vibration characteristics of the crystal resonator element 110 can be suppressed. In addition, since the thickness of the first conductive layers 152 and 154 is 500 nm or less, the amount of metal material including gold (Au) can be reduced. Therefore, reducing the manufacturing cost of the crystal resonator element 110 can shorten the time required for forming the first conductive layers 152 and 154.

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

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

Next, a photoresist is patterned (S15). From the standpoint of adaptability to microfabrication, the photoresist is preferably a positive-type photosensitive resin that removes the exposed portion by dissolution. When a positive-type photosensitive resin is used, the photoresist is exposed in a state where the area corresponding to the central portion 117 is shielded from light by a photomask. Thereafter, the exposed portion was washed with a developing solution. As a result, the shape of the light-shielding area of the photomask is transferred to the photoresist. As a result, the outer shape of the central portion 117 is patterned to the photoresist remaining on the first conductive layers 152 and 154. In addition, the photoresist may be a negative-type photosensitive resin in which a light-shielding portion is removed by dissolution.

Next, the first conductive layer is etched (S16). The removal processing of the first conductive layers 152 and 154 is performed by wet etching using a first etchant containing a potassium iodide aqueous solution as a main component. Since the potassium iodide aqueous solution has a high etching rate for gold (Au) and a low etching rate for chromium (Cr), it is possible to etch the exposed first conductive layers 152 and 154 while making the first contact layers 151 and 153 equivalent to the base. Residual.

Next, the first adhesion layer is etched (S17). The removal processing of the first adhesion layers 151 and 153 is performed by wet etching using a second etchant containing a cerium ammonium nitrate aqueous solution as a main component. Since the cerium ammonium nitrate aqueous solution has a low etching rate for gold (Au) and a high etching rate for chromium (Cr), it is possible to suppress the erosion of the first conductive layers 152 and 154 remaining covered by the patterned photoresist The first adhesive layers 151 and 153 are etched while being exposed.

In this manner, the first etchant and the second etchant are each appropriately selected to have an etching rate different from the etching rate of the first adhesion layer and the first conductive layer. The etched first conductive layer 152 and the first adhesion layer 151 form the shape of the first excitation electrode 114a, and the etched first conductive layer 154 and the first adhesion layer 153 form the shape of the second excitation electrode 114b. In addition, the outer shape formation of the first excitation electrode 114a and the second excitation electrode 114b is not limited to those using wet etching, and may be formed by other removal processes such as dry etching.

Next, the water crystal wafer is etched (S18). Here, the first excitation electrode 114 a and the second excitation electrode 114 b are used as a metal mask for protecting the central portion 117 of the crystal wafer 111, and the processed peripheral portion 118 and the peripheral portion 119 are removed. The removal process of the crystal wafer 111 is performed by wet etching using hydrofluoric acid. As a result, as shown in FIG. 6, a step is generated between the central portion 117 and the peripheral edge portion 118, and a first side surface 112 a connecting the first main surface 117 a of the central portion 117 and the first main surface 118 a of the peripheral edge portion 118 is formed. 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 edge portion 119 is formed, and a second main surface of the second main surface 117b of the central portion 117 and the peripheral edge portion 119 is formed. The second side surface 113b is connected to the surface 119b. That is, the quartz crystal 111 is a concavo-convex member having a mesa-type structure on both sides of the first main surface 111a and the second main surface 111b by removing a part from the flat 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. The formation of the mesa structure of the crystal wafer 111 is not limited to wet etching, and may be formed by other removal processes such as dry etching. However, from the viewpoint of reducing damage to the first excitation electrode 114a and the second excitation electrode 114b, it is preferable to use a wet etcher to remove the crystal wafer 111.

If it is desired to provide an excitation electrode in the central portion of the crystal wafer after the mesa-shaped structure is formed, the film thickness of the photoresist becomes uneven due to the surface tension of the photoresist solution and the like. For example, the photoresist becomes thinner at the corners of the step, and becomes thicker at the flat area. Therefore, the patterning accuracy of the photoresist is reduced, and the shape of the pattern of the photoresist near the corner of the step is unstable. In this way, it is difficult to form an excitation electrode with a uniform film thickness to the edge of the main surface of the central portion. When the main surface of the central portion is viewed from the outside, the outer edge of the excitation electrode is located inside the main surface of the central portion. As described above, if the first excitation electrode 114a is used as a metal mask for forming a mesa structure on the crystal wafer 111, the first excitation electrode 114a can be formed up to the edge of the first main surface 117a of the center portion 117, that is, the center The boundary between the part 117 and the first side surface 112a is up to the boundary. Since the shape of the first main surface 117a of the central portion 117 and the first excitation electrode 114a are the same, variations in the shape of the first excitation electrode 114a can be suppressed, and variations in the frequency characteristics of the crystal resonator element 110 can be suppressed. Similarly, the second excitation electrode 114b may be formed until the boundary between the central portion 117 and the second side surface 112b.

Next, a second adhesion layer is provided (S21). As shown in FIG. 7, a second contact layer 155 constituting a part of the first lead-out electrode 115 a and a part of the second lead-out electrode (not shown) covers the surface of the peripheral portion 118 of the crystal wafer 111 and the first excitation electrode 114 a. The surface and the surface of the second excitation electrode 114b are formed. The second adhesion layer 155 before patterning corresponds to a series of metal films including one of the crystal wafer 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 and 153 in order to have the same structure as the first adhesion layers 151 and 153. That is, the second adhesion layer 155 is a metal film formed by depositing a metal material containing chromium (Cr) by sputtering, and has a thickness of 1 nm to 20 nm.

Next, a second conductive layer is provided (S22). As shown in FIG. 7, the second conductive layer 156 which forms a part of the first lead-out electrode 115 a and a part of the second lead-out electrode (not shown) is formed so as to cover the second adhesion layer 155. The second conductive layer 156 before patterning is equivalent to a series of metal films including one body of the second adhesion layer 155 including the crystal wafer 111. The second conductive layer 156 can be formed by the same method as the first conductive layers 152 and 154 so as to have the same configuration. That is, the second conductive layer 156 is a metal film formed by depositing a metal material containing gold (Au) by sputtering, and has a thickness of 1 nm to 500 nm.

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 in the same manner as the photoresist provided in step S14 in the same manner.

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

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 16, the exposed second conductive layer 156 can be etched while leaving the second adhesion layer 155 corresponding to the base.

Next, the second adhesion layer is etched (S26). At this time, by using the same etching solution as the second etching solution used in step 17, it is possible to etch the exposed second conductive layer 156 while suppressing the erosion of the second conductive layer 156 remaining covered with the patterned photoresist.密接 层 155。 Close contact layer 155. As shown in FIG. 9, by etching the second adhesion layer 155, the first conductive layer 152 of the first excitation electrode 114 a and the first conductive layer 154 of the second excitation electrode 114 b are exposed. Since the second etching solution has a low etching rate for gold (Au), the first conductive layer 152 of the first excitation electrode 114a and the first conductive layer 154 of the second excitation electrode 114b can be suppressed from being etched by the etching solution. Cause erosion.

As described above, the excitation electrode and the extraction electrode are provided in a two-layer structure, and wet etching is performed using an etching solution having a different etching rate for each layer, so that the extraction electrode can be patterned while suppressing damage to the excitation electrode. Furthermore, the formation of the lead-out electrode is not limited to wet etching using a photolithography method. The lead-out electrode can also be arranged around the crystal wafer 111 by a sputtering mask that has been patterned with the shape of the lead-out electrode, and the second adhesion layer 155 and the second conductive layer 156 can be sputtered through the sputtering mask. Instead, patterning is performed.

Next, the electrode surface at the center is cut (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 cut by ion polishing. This reduces the thickness of the electrode formed in the central portion 117 and adjusts the frequency characteristics of the crystal vibration element 110. Through the above steps, the crystal vibration element 110 having the required frequency characteristics is manufactured. In addition, the cutting surface in step S26 may be an electrode of at least one of the first main surface 117a side and the second main surface 117b side of the central portion 117, or may be an electrode of both.

Hereinafter, other embodiments will be described. In each of the following embodiments, descriptions of matters common to the first embodiment described above will be omitted, and only differences will be described. The configuration to which the same reference numerals as those of the first embodiment are added is assumed to have the same configurations and functions as those of the first embodiment, and detailed descriptions thereof will be omitted. No mention is made of the same effects regarding the same constitution.

<Second Embodiment>

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

The crystal resonator element 210 includes a quartz crystal 211, a first excitation electrode 214a, a second excitation electrode 214b, a first extraction electrode 215a, and a first connection electrode 216a. The quartz crystal 211 includes a central portion 217 and peripheral portions 218 and 219. The quartz crystal 211 forms a first side surface 212a connecting the first main surface 217a and the first main surface 218a between the central portion 217 and the peripheral portion 218, and forms a connection between the second main surface 217b and the second main surface 218b. The second side 212b. The quartz crystal 211 forms a first side surface 213a connecting the first main surface 217a and the first main surface 219a between the central portion 217 and the peripheral portion 219, and forms a connection between the second main surface 217b and the second main surface 219b. Second side 213b. The first excitation electrode 214a includes a first adhesion 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 lead-out electrode 215a includes a second adhesion layer 255 and a second conductive layer 256.

The difference from the crystal vibrating element 10 of the first embodiment is the point where the quartz crystal 211 has an inverted table structure. That is, the peripheral edge portions 218 and 219 are thicker than the central portion 217. The quartz crystal 211 is a two-sided inverted table type structure in which both sides of the first main surface 217a and the second main surface 217b of the central portion 217 are recessed. In addition, the quartz crystal 211 may have a single-sided inverted table-type structure in which the first main surface 217a and the second main surface 217b of the central portion 217 are recessed on one side.

In such a crystal vibrating element 210, the same effects as described above can also 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 a configuration of a crystal oscillator according to a third embodiment. Fig. 13 is a cross-sectional view schematically showing a configuration of a crystal oscillator according to a third embodiment.

The crystal oscillator 900 has a so-called sandwich structure in which a crystal vibration element 910 is separated between a first cover member 920a and a second cover member 920b. The crystal resonator element 910 includes a quartz crystal 911, a first excitation electrode 914a, a second excitation electrode 914b, a first extraction electrode 915a, and a second extraction electrode 915b. The first cover member 920a is bonded to the first main surface 911a of the quartz chip 911 via the first sealing member 937a, and the second cover member 920b is bonded to the second main surface 911b of the quartz chip 911 via the second sealing member 937b.

When the first main surface 911a of the crystal piece 911 is viewed in plan, the crystal piece 911 includes a central portion 917 and a peripheral portion 919 surrounding the central portion 917 with a gap. 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 portion of the peripheral portion. A first side surface 912a connecting the first main surface 917a of the central portion 917 and the first main surface 918a of the supporting portion 918 is formed between the support portion 918 and the central portion 917, and a second main surface connecting the central portion 917 is formed. 917b is a second side surface 912b connected to the second main surface 918b of the support portion 918. Further, a third side surface 913 is formed at an end portion on the slit side of the central portion 917 to connect the first main surface 917a of the central portion 917 and the second main surface 917b. The first cover member 920a is joined to the first main surface 919a of the peripheral portion 919, and the second cover member 920b is joined to the second main surface 919b of the peripheral portion 919.

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

In such a crystal vibration element 910, the same effects as described above can also be obtained.

<Fourth Embodiment>

The configuration of the crystal resonator element 410 according to the fourth embodiment will be described with reference to FIG. 14. Fig. 14 is a perspective view schematically showing a configuration of a crystal resonator element according to a fourth embodiment.

This embodiment differs from the first embodiment in that it includes a peripheral portion PR1 adjacent to the central portion 417 on the positive side of the Z ′ axis and a peripheral portion adjacent to the central portion 417 on the negative side of the Z ′ axis. The point of PR2. The peripheral edge portion PR1 is connected to one end of each of the peripheral edge portions 418 and 419, and the peripheral edge portion PR2 is connected to the other end of each of the peripheral edge portions 418 and 419. When the first main surface 411a of the crystal piece 411 is viewed in plan, the peripheral edge portions 418, 419, PR1, and PR2 are provided in a rectangular frame shape, and the central portion 417 is provided in an island shape surrounded by the peripheral edge portions 418, 419, PR1, and PR2. A first excitation electrode 414a is provided on the entire surface of the first main surface 417a of the central portion 417, and a peripheral portion 418 is provided with a first extraction electrode 415a and a first connection electrode 416a. Furthermore, on the second main surface side (not shown), the central portion 417 also has an island shape surrounded by peripheral portions 418, 419, PR1, and PR2, and a second main surface on the central portion 417 is also provided with a first portion. 2Excitation electrode. In such a crystal vibration element 410, the same effects as described above can also be obtained.

As described above, if the first and second excitation electrodes are formed on the entire surface of each 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, when the first main surface of the crystal wafer is viewed from the top, the shape of the central portion may be a circle or an ellipse, or a polygon other than a quadrangle.

In addition to the step difference formed between the peripheral edge portion and the central portion, a step difference may be further formed on the first main surface side and the second main surface side of the quartz crystal. 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 portion, and the thick-walled region in the central portion is adjacent to the thin-walled region on the opposite side from the peripheral portion. The thin-walled region in the central portion may also be formed into a full-width strip shape extending from one end to the other end of the wafer in the Z′-axis direction. At this time, the thick-walled region of the central portion may be formed in the shape of a strip across the full width of the quartz chip, or may be formed into an island shape surrounded by the thin-walled region of the central portion, similarly to the thin-walled region of the central portion. When the thick-walled area of the central portion is formed into a band shape, the thick-walled area of the central portion may be separated between the thin-walled area of the central portion in the X-axis direction, or only in the positive and negative directions of the X-axis direction. Either side is adjacent to the thin-walled area of the central portion. Furthermore, the positional relationship between the thin-walled area and the thick-walled area in the central portion may be reversed. That is, the thick-walled area of the central portion may be adjacent to the peripheral edge portion, and the thin-walled area of the central portion may be adjacent to the thick-walled area on the opposite side from the peripheral edge portion.

As a structure in which a step is further formed on the first principal surface side and the second principal surface side of the quartz crystal, for example, a thin-walled region and a thick-walled region are formed in the peripheral portion, and the thick-walled region of the peripheral portion is adjacent to the central portion, and the peripheral portion The thin-walled region is adjacent to the thick-walled region on the opposite side from the central portion. The thick-walled region of the peripheral portion may also be formed in a band-like shape across the full width of the crystal piece. At this time, the central portion may be formed in the shape of a strip extending over the full width of the crystal chip in the same manner as the thick-walled region of the peripheral portion, or may be formed into an island shape surrounded by the thick-walled region of the peripheral portion. The thick-walled region of the peripheral portion may be formed in an island shape surrounded by a thin-walled region. At this time, the central portion may be formed in a belt shape extending over the entire width of the thick-walled region, or may be formed in an island shape surrounded by the thick-walled region. Furthermore, the positional relationship between the thick-walled area and the thin-walled area of the peripheral portion may be reversed. That is, the thin-walled region of the peripheral portion may be adjacent to the central portion, and the thick-walled region of the peripheral portion may be adjacent to the thin-walled region on the opposite side from the central portion.

As described above, according to one aspect of the present invention, a method for manufacturing a crystal vibrating element 110 is provided, which includes a step of preparing a crystal wafer 111 having a first main surface 111a and facing the first main surface 111a. The second main surface 111b includes a central portion 117 on the central side and a peripheral portion 118 on the outer side of the central portion 117 when the first main surface 111a is viewed in plan. The first main surface 111a of the crystal plate 111 is provided on the central portion 117. Step of the first excitation electrode 114a; while using the first excitation electrode 114a as a metal shield for protecting the central portion 117, removing a part of the peripheral edge portion 118, on the side of the first main surface 111a of the crystal wafer 111 to the central portion 117 and the peripheral edge A step of forming a first side surface 112a between the portions 118; a first lead extending to the peripheral edge portion 118 on the first main surface 111a side of the crystal plate 111 so as to be in contact with the first excitation electrode 114a used as a metal mask Step of electrode 115a.

According to the above aspect, the first excitation electrode can be formed until the edge of the first main surface of the central portion, that is, the boundary between the central portion and the first side surface. By matching the shape of the first main surface of the central portion with the shape of the first excitation electrode, it is possible to suppress variations in the shape of the first excitation electrode and to suppress variations in the frequency characteristics of the crystal resonator element. It can improve the utilization efficiency of the area that contributes to the excitation in the central part and miniaturize the crystal vibration element. In addition, the sealing efficiency of the excited vibration in the central portion can be improved.

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

The first lead-out electrode 115a may cover at least a part of the first excitation electrode 114a on the central portion 117 when the first main surface 111a of the crystal wafer 111 is viewed from the top. Thereby, 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 stable. In addition, damage to the first excitation electrode can be suppressed, and deterioration in frequency characteristics of the crystal resonator element can be suppressed.

The step of providing the first excitation electrode 114a may also include: a step of providing a first adhesive layer 151 on the first main surface 111a side of the crystal wafer 111; and a step of providing a first conductive layer 152. The first conductive layer 152 has The first adhesion layer 151 has high electrical conductivity, and covers the first adhesion layer 151 when the first main surface 111 a of the crystal wafer 111 is viewed in plan. Thereby, the first adhesion layer having high reactivity with oxygen can be increased by the substrate, and the adhesion between the crystal chip and the first excitation electrode can be increased. The first conductive layer having low reactivity with oxygen can be prevented from being oxidized by the surface. The degradation of the first excitation electrode. That is, the reliability of the crystal resonator element can be improved.

The step of providing the first lead-out electrode 115a may also include: a step of providing a second adhesion layer 155 on the first main surface 111a side of the crystal wafer 111; and a step of providing a second conductive layer 156. The second conductive layer 156 has The second adhesion layer 155 has high electrical conductivity, and covers the second adhesion layer 155 when the first main surface 111 a of the crystal wafer 111 is viewed in plan. Thereby, the second adhesive layer having high reactivity with oxygen can be increased by the substrate, and the adhesion between the crystal chip and the first lead-out electrode can be improved. The second conductive layer having low reactivity with oxygen can be prevented from being oxidized by the surface. Deterioration of the first lead-out electrode. That is, the reliability of the crystal resonator element can be improved.

The first adhesion layer 151 and the second adhesion layer 155 are each made of a metal material containing chromium, and the first conductive layer and the second conductive layer may be each made of a metal material containing gold. Accordingly, the adhesion between chromium (Cr) and crystal is higher than that of gold (Au), and gold (Au) has higher electrical conductivity and higher chemical stability than chromium (Cr). Therefore, the above-mentioned effects can be obtained.

The step of setting the first lead-out electrode 115a may also include the step of setting the metal films 155 and 156; the step of setting the photoresist 161 covering the metal films 155 and 156; and patterning the photoresist 161 into the first lead-out electrode 115a. Step of shape; step of etching metal films 155, 156. Accordingly, compared with the case where the first excitation electrode and the first extraction electrode are formed in the same steps by the photolithography method, the required accuracy of patterning is lower, and thus the manufacturing cost can be suppressed.

The step of providing the first lead-out electrode may also include: a step of providing a first metal film on the first main surface side of the crystal wafer and a step of providing a second metal film so as to cover the first metal film; and a light covering the second metal film. A resist step; a step of patterning the photoresist into the shape of the first lead-out electrode; a step of etching the second metal film using the first etchant to expose the first metal film; using an etching with the first etchant A step of etching the first metal film by the second etching solution having different speeds. Accordingly, when the first lead-out electrode shape is formed by wet etching, since the damage to the first excitation electrode can be reduced, the manufacturing error of the frequency characteristics of the crystal resonator element can be suppressed.

The step of setting the first lead-out electrode 115a may include the step of arranging a sputtering mask patterned with the shape of the first lead-out electrode 115a on the side of the first main surface 111a of the crystal wafer 111; Steps of sputtering metal films 155 and 156. As a result, the number of steps can be reduced compared with the case where the first lead-out electrode profile is formed by the photolithography method.

It may further include a step of reducing the thickness of the electrodes 114a and 115a provided in the central portion 117 and adjusting the frequency. This can suppress manufacturing errors in the frequency characteristics of the crystal vibration element.

It may further include a step of providing a second excitation electrode 114b opposite to the first excitation electrode 114a in the central portion 117 of the second main surface 111b of the crystal wafer 111; and using the second excitation electrode 114b as the protection of the central portion 117 A metal mask, removing a part of the peripheral edge portions 118 and 119, and forming a second side surface 112b, 113b between the central portion 117 and the peripheral edge portion 118 on the second main surface 111b side of the quartz plate 111; and as a metal In the method of contacting the second excitation electrode 114b used in the mask, a step of providing a second extraction electrode 115b extending to the peripheral edge portion 118 on the second main surface 111b side of the crystal wafer 111. Thereby, the same effects as described above can be obtained.

According to another aspect of the present invention, a crystal vibrating element 10 is provided. The crystal vibrating element 10 has a first main surface 11a and a second main surface 11b opposite to the first main surface 11a, and has a first main surface in plan view. At 11a, the central portion 17 on the central side and the peripheral portions 18 and 19 on the outer side of the central portion 17 are provided. The crystal portion 11 includes at least one of the first main surface 11a and the second main surface 11b of the crystal piece. 1 The main surface 11a is formed with first side surfaces 12a and 13a between the central portion 17 and the peripheral portions 18 and 19; a first excitation electrode 14a provided on the central portion 17 in the first main surface 11a of the crystal piece 11; The second main surface 11b of the quartz chip 11 is provided at the central portion 17 and is opposite to the first excitation electrode 14a. The second excitation electrode 14b is electrically connected to the first extraction electrode 15a of the first excitation electrode 14a. When the second lead-out electrode 15b of the second excitation electrode 14b is viewed from above; when the first main surface 11a of the crystal wafer 11 is viewed from the top, the first lead-out electrode 15a covers at least a part of the first excitation electrode 14a and extends from the central portion 17 to the peripheral portion. 18.

According to the above aspect, by forming the first excitation electrode up to the edge of the first main surface of the central portion, that is, the boundary between the central portion and the first side surface, the utilization of the central portion that contributes to the excitation can be improved. Efficiency, miniaturization of crystal vibration elements. In addition, the sealing efficiency of the excited vibration in the central portion can be improved. Since the first lead-out electrode covers a part of the first lead-out electrode, the contact area between the first lead-out electrode and the first lead-out electrode increases, and the electrical connection between the first lead-out electrode and the first lead-out electrode is stable. In addition, damage to the first excitation electrode can be suppressed, and deterioration in frequency characteristics of the crystal resonator element can be suppressed.

When the first main surface 11a of the crystal wafer 11 is viewed in plan, the outer edge of the first excitation electrode 14a may extend to the boundary between the central portion 17 and the first side surface 12a. Thereby, by matching the shape of the first main surface of the central portion with the shape of the first excitation electrode, variation in the shape of the first excitation electrode can be suppressed, and variation in the frequency characteristics of the crystal resonator element can be suppressed.

The first excitation electrode 14 a may include a first adhesion layer 51 provided on the first main surface 11 a side of the crystal wafer 11, and a first main surface having a higher conductivity than the first adhesion layer 51 when viewed from above. At 11a, the first conductive layer 52 covering the first adhesion layer 51 is covered. Therefore, the first adhesion layer having high reactivity with oxygen can be increased by the substrate, and the adhesion between the crystal chip and the first excitation electrode can be improved. The first conductive layer having low reactivity with oxygen can be suppressed by the surface. Deterioration of the first excitation electrode due to oxidation. That is, the reliability of the crystal resonator element can be improved.

The first lead-out electrode 15a may include: a second adhesion layer 55 provided on the first main surface 11a side of the quartz chip 11; and a first principal surface having a higher conductivity than the second adhesion layer 55 when viewed from above. At 11a, the second conductive layer 56 of the second adhesion layer 55 is covered. Therefore, the second adhesion layer having high reactivity with oxygen can be increased by the substrate, and the adhesion between the crystal chip and the first lead-out electrode can be improved. The second conductive layer having low reactivity with oxygen can be suppressed by the surface. Deterioration of the first lead electrode due to oxidation. That is, the reliability of the crystal resonator element can be improved.

The first adhesion layer 51 and the second adhesion layer 55 may 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. Accordingly, the adhesion between chromium (Cr) and crystal is higher than that of gold (Au), and gold (Au) has higher electrical conductivity and higher chemical stability than chromium (Cr). Therefore, the effects described above can be obtained.

The thickness T3 of the portion of the first extraction electrode 15a provided at the central portion 17 may be smaller than the thickness T4 of the portion of the first extraction electrode 15a provided at the peripheral portion 18. Thereby, the frequency characteristics of the crystal vibrating element can be adjusted by cutting the surface of the electrode provided at the center portion. Therefore, manufacturing errors in the frequency characteristics of the crystal resonator element can be suppressed.

The thickness of the central portion 17 may be larger than the thickness of the peripheral portions 18 and 19, and the first side surfaces 12a and 13a may also connect the central portion 17 and the peripheral portions 18 and 19. Thereby, the above-mentioned effects can be obtained in the step difference formed by the so-called mesa-type structure.

The thickness of the central portion 217 may be 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. Thereby, the above-mentioned effect can be obtained in the step formed by the so-called inverted mesa structure.

The second side surface 12b, 13b is formed between the central portion 17 and the peripheral portions 18, 19 on the side of the second main surface 11b of the crystal piece 11. When the second main surface 11b of the crystal piece 11 is viewed in plan, the second lead-out electrode 15b may be used. It covers at least a part of the second excitation electrode 14 b and extends from the central portion 17 to the peripheral edge portion 18 on the second main surface 11 b side of the crystal piece 11. Thereby, the same effects as described above can be obtained.

The quartz crystal 911 may form a slit between the central portion 917 and the peripheral portion 919. In such a configuration, the above-mentioned effects can also be obtained.

As described above, according to one aspect of the present invention, it is possible to provide a crystal vibrating element and a method for manufacturing the same that can reduce manufacturing errors of vibration characteristics.

In addition, the embodiments described above are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed / improved without departing from the gist thereof, and the present invention includes equivalents thereof. That is, a person with ordinary knowledge in the technical field to which the invention pertains applies appropriate design changes to each embodiment as long as it has the features of the present invention, and is included in the scope of the present invention. For example, each element provided in each embodiment and its arrangement, material, conditions, shape, size, and the like are not limited to the examples, and can be appropriately changed. In addition, each element provided in each embodiment can be combined as long as it is technically possible, and a combination of these elements is also included in the scope of the present invention as long as the features of the present invention are included.

Claims (21)

    A method for manufacturing a crystal vibrating element, comprising the steps of preparing a crystal chip, the crystal chip having a first main surface and a second main surface facing the first main surface, and having a first main surface positioned above the first main surface in plan view; A central portion of the central side and a peripheral portion located on the outer side of the central portion; a step of providing a first excitation electrode in the central portion of the first main surface of the quartz chip; and using the first excitation electrode as a protection of the center A step of forming a first side surface between the central portion and the peripheral edge portion on the first main surface side of the crystal wafer while removing a part of the peripheral edge portion of the metal mask; and In the method of contacting the first excitation electrode used in the cover, a step of providing a first lead-out electrode extending to the peripheral portion on the first main surface side of the crystal wafer.         The method for manufacturing a crystal resonator element according to claim 1, wherein the first lead-out electrode passes through the first side surface.         The method for manufacturing a crystal vibrating element according to claim 1, wherein the first lead-out electrode covers at least a part of the first excitation electrode at the central portion when the first lead-out electrode is viewed from the first main surface of the crystal wafer.         The method for manufacturing a crystal vibration element according to any one of claims 1 to 3, wherein the step of providing the first excitation electrode includes: a step of providing a first adhesion layer on the first main surface side of the crystal wafer; And a step of providing a first conductive layer, the first conductive layer has higher conductivity than the first adhesion layer, and covers the first adhesion layer when the first main surface of the crystal wafer is viewed from above.         The method for manufacturing a crystal vibration element according to claim 4, wherein the step of providing the first lead-out electrode includes a step of providing a second adhesion layer on the first main surface side of the crystal wafer; and providing a second conductive layer In this step, the second conductive layer has higher conductivity than the second adhesion layer, and covers the second adhesion layer when the first main surface of the crystal wafer is viewed from above.         The method for manufacturing a crystal vibration element according to claim 5, wherein the first adhesion layer and the second adhesion layer are each composed of a metal material containing chromium, and the first conductive layer and the second conductive layer are each composed of Made of gold metal material.         The method for manufacturing a crystal vibration element according to any one of claims 1 to 3, wherein the step of setting the first lead-out electrode includes: a step of setting a metal film; a step of setting a photoresist covering the metal film; A step of patterning the photoresist into the shape of the first lead-out electrode; and a step of etching the metal film.         The method for manufacturing a crystal vibration element according to any one of claims 1 to 3, wherein the step of providing the first lead-out electrode includes: providing a first metal film on the first main surface side of the crystal wafer; and A step of providing a second metal film in a manner of covering the first metal film; a step of providing a photoresist covering the second metal film; a step of patterning the photoresist into the shape of the first lead-out electrode; A step of etching the first metal film by exposing the first metal film and etching the second metal film using a first etching solution; and a step of etching the first metal film using a second etching solution having a different etching rate from the first etching solution.         The method for manufacturing a crystal vibration element according to any one of claims 1 to 3, wherein the step of setting the first lead-out electrode includes: arranging a sputtering mask patterned with the shape of the first lead-out electrode in A step of the first main surface side of the crystal piece; and a step of sputtering a metal film by the sputtering mask.         The method for manufacturing a crystal vibration element according to any one of claims 1 to 3, further comprising a step of reducing a thickness of an electrode provided in the central portion and adjusting a frequency.         The method for manufacturing a crystal vibrating element according to any one of claims 1 to 3, further comprising: in the second main surface of the crystal wafer, a second portion facing the first excitation electrode is provided in the central portion. 2 step of stimulating electrodes; while using the second stimulating electrode as a metal shield to protect the central portion, removing a part of the peripheral edge portion, on the second main surface side of the crystal piece, on the central portion and the peripheral edge A step of forming a second side surface between the parts; and a second lead extending to the peripheral edge portion on the second main surface side of the crystal wafer in a manner to contact the second excitation electrode used as the metal mask Electrode steps.         A crystal vibrating element comprising a crystal chip having a first main surface and a second main surface facing the first main surface, and having a central portion located on a central side when the first main surface is viewed in plan, and A peripheral edge portion on the outer side of the central portion is at least a first principal surface side of the first principal surface and the second principal surface, and a first lateral surface is formed between the central portion and the peripheral edge portion; a first excitation electrode And is provided on the central portion on the first main surface of the quartz chip; and a second excitation electrode is provided on the central portion on the second main surface of the quartz chip and is the same as the first excitation electrode Opposite; the first extraction electrode is electrically connected to the first excitation electrode; and the second extraction electrode is electrically connected to the second excitation electrode; and when the first main surface of the crystal wafer is viewed from above, The first extraction electrode covers at least a part of the first excitation electrode, and extends from the central portion to the peripheral portion.         The crystal vibrating element according to claim 12, wherein when the first main surface of the crystal wafer is viewed from above, the outer edge of the first excitation electrode extends to the boundary between the central portion and the first side surface.         The crystal vibrating element according to claim 12, wherein the first excitation electrode includes: a first adhesion layer provided on the first main surface side of the quartz crystal chip; and a first conductive layer having a thickness greater than that of the first The adhesion layer has high electrical conductivity, and covers the first adhesion layer when the first principal surface of the crystal wafer is viewed from above.         The crystal vibrating element according to claim 14, wherein the first lead-out electrode includes: a second adhesion layer provided on the first main surface side of the crystal wafer; and a second conductive layer having a second conductive layer that is more than the second conductive layer. The adhesion layer has high electrical conductivity, and covers the second adhesion layer when the first main surface of the crystal wafer is viewed from above.         The crystal vibration element according to claim 15, wherein the first adhesion layer and the second adhesion 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 containing gold. Made of materials.         The crystal vibration element according to any one of claims 12 to 16, wherein a thickness of a portion of the first lead-out electrode provided on the central portion is greater than a thickness of a portion of the first lead-out electrode provided on the peripheral portion. small.         The crystal vibration element according to any one of claims 12 to 16, wherein a thickness of the central portion is larger than a thickness of the peripheral portion, and the first side surface connects the central portion and the peripheral portion.         The crystal vibration element according to any one of claims 12 to 16, wherein the thickness of the central portion is smaller than the thickness of the peripheral portion, and the first side surface connects the central portion and the peripheral portion.         The crystal vibrating element according to any one of claims 12 to 16, wherein the quartz crystal has a second side surface formed between the central portion and the peripheral edge portion on the second main surface side, and the second lead-out electrode is When the second main surface of the crystal wafer is viewed from above, it covers at least a part of the second excitation electrode, and extends from the central portion to the peripheral edge portion on the second main surface side of the crystal wafer.         The crystal vibration element according to any one of claims 12 to 16. In the crystal wafer, a slit is formed between the central portion and the peripheral portion.