JP2012257141A - Crystal vibrating piece, gyro sensor, electronic apparatus and manufacturing method of crystal vibrating piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal vibrating piece in which deterioration of vibration characteristics due to etching anisotropy of crystal is suppressed, and further to provide a gyro sensor using the crystal vibrating piece, an electronic apparatus provided therewith and a manufacturing method of the crystal vibrating piece.SOLUTION: A crystal vibrating piece comprises a base portion 21 and a vibration arm 22 that extends from the base portion 21. In the crystal vibrating piece, a groove 2 with a bottom having an opening portion is formed at a first surface 1a of the vibration arm 22 and is arranged so as to be disposed at a position in which a virtual line P2 passing through a center of the opening portion in the first surface 1a and extending in an extension direction of the vibration arm 22 is shifted in any direction parallel to a virtual line P1 passing through a center of gravity of the vibration arm 22 before the groove 2 is formed and extending in the extension direction of the vibration arm 22. A manufacturing method of a vibrating element 20 as the crystal vibrating piece includes a step of exposing outer shapes of the base portion 21 and the vibration arm 22 and an opening portion shape of the groove 2 to a photoresist film applied to the first surface 1a of a crystal wafer by using the same photo mask.

Description

  The present invention relates to a crystal vibrating piece, a gyro sensor, an electronic device using the same, and a method for manufacturing the crystal vibrating piece.

  Conventionally, in consumer and industrial electronic devices such as watches, home appliances, various information communication devices and OA devices, a piezoelectric resonator such as a crystal resonator or a crystal resonator element is used as a clock source for the electronic circuit. Piezoelectric devices such as oscillators and real-time clock modules in which a piezoelectric vibrating piece and an IC chip are sealed in the same package are widely used. Piezoelectric vibrators that use piezoelectric vibrating reeds as sensor elements (vibration elements) as rotational angular velocity sensors for attitude control and navigation control of ships, aircraft, automobiles, and camera shake detection / correction control of digital cameras, digital video cameras, etc. A gyro sensor as a device is widely used and applied to a rotation direction sensor such as a three-dimensional solid mouse. As such a gyro sensor, for example, one described in Patent Document 1 or Patent Document 2 is known.

  These piezoelectric devices are required to be further reduced in size and thickness as electronic devices on which they are mounted are reduced in size and thickness. In addition, there is a demand for a piezoelectric device that reduces the crystal impedance value (hereinafter referred to as the CI value) and has high quality and excellent stability. In order to reduce the CI value, for example, a tuning-fork type piezoelectric vibrating piece having a grooved vibrating portion (vibrating arm) described in Patent Document 3 is introduced. The piezoelectric vibrating piece described in Patent Document 3 has a base portion made of, for example, quartz and a pair of vibrating portions extended from the base portion, and grooves extending in the extending direction of the vibrating portion are formed in each vibrating portion. . A structure in which the rigidity of the vibration part is reduced by the groove provided in each vibration part to promote vibration, and the CI value can be suppressed by improving the electric field efficiency by providing excitation electrodes on the side surface and the bottom surface of the groove. It has become.

  When using a tuning-fork type crystal vibrating piece as a vibrating element, an excitation electrode (driving electrode) is provided on one of a pair of vibrating parts (vibrating arms) and used as a driving part, and the other vibrating part is used on the other vibrating part. A detection electrode is provided and used as a detection unit. When an excitation signal is applied to the excitation electrode of the vibration element having such a configuration to cause excitation vibration in an in-plane direction perpendicular to the extending direction of the vibrating part, the axis around the extending direction of the vibrating part is an axis. When a rotational motion is applied, the rotational motion generates a Coriolis force in a direction (out-of-plane direction) orthogonal to the excitation vibration direction, and generates vibration in the out-of-plane direction through the base portion to the other vibration portion. By detecting the out-of-plane vibration of the other vibration part (detection part) by converting it into an electrical signal by the detection electrode, the rotational angular velocity applied to the vibration element can be detected.

JP-A-7-55479 JP-A-10-170272 JP 2004-200917 A

The outer shape of the tuning-fork type crystal vibrating piece as described above is usually formed by wet etching a crystal wafer using photolithography. Here, since the piezoelectric single crystal material such as quartz has etching anisotropy, the cross-sectional shape of the wet-etched vibrating arm or groove may be asymmetric with respect to the center line along the etching direction depending on the crystal orientation. In many cases, this tendency is known to be particularly remarkable in quartz among piezoelectric single crystal materials. As described above, since the vibration part has an asymmetric cross-sectional shape, the in-plane vibration and the out-of-plane vibration of the vibration part described above are not in a desired direction, and the vibration characteristics are deteriorated, or the vibration piece is used as a gyro element. In this case, there is a problem that the vibration part vibrates in the detection direction (out-of-plane direction) in spite of the state where the rotation angular velocity is zero, thereby degrading the detection accuracy of the rotation angular velocity of the vibration element.
In addition, in order to secure the positional accuracy of exposure when forming grooves using photolithography, an extremely high-precision aligner (exposure device) is required, which may increase the manufacturing cost, and in particular, crystal As the size of the resonator element is reduced, the alignment of the photomask becomes more difficult and the position accuracy is lowered, and it is very difficult to form a groove at a desired position of the vibration portion.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 A method of manufacturing a quartz crystal resonator element according to this application example includes a base, a second surface extending from the base, and a second surface on the opposite side of the first surface, and And a vibrating part having a pair of side surfaces connecting the first surface and the second surface. A method for manufacturing a quartz crystal vibrating piece, comprising: a photoresist film on the first surface of a quartz substrate; And using the same photomask, exposing the photoresist film with the outer shape of the base and the vibrating portion and the shape of the opening of the groove in the forming region of the vibrating portion And developing the photoresist film after the exposing step, etching the outer shape and the groove by a wet etching method using the photoresist film patterned in the developing step as a mask, Including the groove The opening is characterized by being formed deviated to one side of the side in plan view.
Further, by simultaneously performing the outer shape formation and the groove formation of the vibration part, the groove can be formed deeply, and unnecessary vibration modes other than the desired vibration can be greatly suppressed. Further, as a synergistic effect, if the excitation electrode is formed inside the deep groove, the distance between the inner wall of the groove and the outer wall of the vibrating arm is reduced, so that the excitation electric field efficiency is improved, thereby improving the vibration characteristics.

According to this manufacturing method, the vibration part and the groove of the crystal vibrating piece are simultaneously exposed using the same photomask, so that the outer shape of the vibration part can be increased without increasing the number of high-performance equipment and increasing the manufacturing process. The groove with respect to it can be formed in a desired positional relationship with high positional accuracy.
Accordingly, it is possible to manufacture a small-sized quartz crystal resonator element having stable vibration characteristics in which deterioration of vibration characteristics and temperature characteristics due to etching anisotropy of the quartz material is suppressed.

  Application Example 2 In the method of manufacturing a quartz crystal resonator element according to the application example, the groove includes an imaginary line passing through the center of the opening on the first surface and extending along the extending direction. It has shifted | deviated with respect to the virtual line which followed the gravity center of the said vibration part before forming and followed the said extending | stretching direction.

  According to this configuration, the unnecessary vibration mode other than the desired vibration can be greatly suppressed by shifting the position of the groove from the center and shifting the position of the center of gravity of the vibration part from before the groove is formed.

  Application Example 3 In the method for manufacturing a quartz crystal resonator element according to the application example described above, the method includes a step of etching from the second surface after the etching step.

  According to this configuration, since at least a part of the etching residue (fins) that remarkably occurs at a deep etching position due to the etching anisotropy of the crystal can be removed by the back surface etching, the cross-sectional shape of the vibration part As a result, the crystal resonator element having more stable vibration characteristics can be provided.

  Application Example 4 In the method of manufacturing a quartz crystal resonator element according to the application example, the etching step is characterized in that etching is performed simultaneously from both sides of the first surface and the second surface.

  According to this configuration, since etching is simultaneously performed from both the first surface and the second surface of the crystal wafer, the etching residue that occurs remarkably at a deep etching position due to the crystal etching anisotropy. Is less likely to occur, the symmetry of the cross-sectional shape of the vibration part is improved, and the vibration characteristics can be stabilized.

  Application Example 5 A quartz crystal resonator element according to this application example includes a base, a first surface extending from the base, a second surface on the opposite side of the first surface, and the first And a vibrating portion having a pair of side surfaces connected to the second surface and the second surface, and a groove is provided in the first surface of the vibrating portion, and the opening of the groove is a plan view. And the depth of the groove is deeper than half of the thickness of the vibrating part from the first surface to the second surface.

The shape of the crystal vibrating piece of this application example in which the groove is deeper than half the thickness of the vibrating portion is attributed to the method of manufacturing the crystal vibrating piece of the application example. That is, the groove reaches the position where the thickness of the vibrating part is deep in order to simultaneously etch the outer shape and groove of the vibrating part penetrating in the thickness direction of the quartz wafer after exposing the outer shape and groove of the vibrating part simultaneously It is. The crystal resonator element manufactured by this manufacturing method can form the outer shape of the vibration part and the groove with respect to it in a desired positional relationship with high positional accuracy without increasing the number of high-performance equipment and increasing the manufacturing process. Can do.
Therefore, it is possible to provide a crystal resonator element having stable vibration characteristics, in which deterioration of vibration characteristics and temperature characteristics due to etching anisotropy of the quartz material is suppressed.
Further, by forming the groove deeply, unnecessary vibration modes other than the desired vibration can be greatly suppressed. Further, as a synergistic effect, if the excitation electrode is formed inside the deep groove, the distance between the inner wall of the groove and the outer wall of the vibrating arm is reduced, so that the excitation electric field efficiency is improved, thereby improving the vibration characteristics.

  Application Example 6 In the quartz crystal resonator element according to the application example described above, the vibrating portion includes at least an electrode, and at least a part of the electrode is provided on an inner wall of the groove.

  According to this configuration, the groove provided in each vibration part reduces the rigidity of the vibration part and promotes vibration, and the effect of improving the electric field efficiency by providing excitation electrodes on the side surface and the bottom surface of the groove. The CI value can be further reduced by working synergistically.

  Application Example 7 A gyro sensor according to this application example includes the quartz crystal resonator element according to any one of the application examples described above.

  According to this configuration, since the vibration element is provided as a crystal vibrating piece in which the mechanical coupling between the drive vibration and the detection vibration that can be generated by the cross-sectional shape being asymmetric due to the etching anisotropy of the crystal wafer is suppressed. In addition, it is possible to provide a gyro sensor with high rotational angular velocity detection accuracy.

  Application Example 8 An electronic apparatus according to this application example includes the quartz crystal resonator element according to any of the application examples described above.

  Since the electronic device having the above-described configuration includes the crystal resonator element of the above application example, that is, the crystal resonator element having a groove formed by exposure and etching at the same time as the outer shape of the oscillator, With stable characteristics.

It is a schematic diagram showing a schematic configuration of an embodiment of a vibration element as a crystal vibrating piece, (a) is a plan view seen from the first surface side (upper side) of the vibration part having an opening of the groove, (b) is the sectional view on the AA line of (a). The flowchart which shows the manufacturing method of a vibration element. (A)-(c) is a front sectional view which shows typically the manufacture process of the vibration part of a vibration element. (A)-(d) is a front sectional view which shows typically the manufacture process of the vibration part of a vibration element. The flowchart which shows the modification 1 of the manufacturing method of a vibration element. (A)-(d) is a front sectional view which shows typically the manufacture process of the vibration part in the modification 1 of the manufacturing method of a vibration element. 9 is a flowchart showing a second modification of the method for manufacturing a vibration element. (A)-(c) is a front sectional view which shows typically the manufacture process of the vibration part in the modification 2 of the manufacturing method of a vibration element. (A)-(d) is a front sectional view which shows typically the manufacture process of the vibration part in the modification 2 of the manufacturing method of a vibration element. It is a schematic diagram explaining the vibration gyro element (modification 3) as a crystal vibrating piece, (a) is a top view, (b) is the BB sectional drawing of (a). The top view which shows typically the H type vibration gyro element as a modification (modification 4) of a quartz-crystal vibrating piece. The top view which shows typically the tripod type vibration gyro element as a modification (modification 4) of a crystal vibrating piece. It is a schematic diagram which shows the gyro sensor provided with the vibration gyro element of the said modification 3 as an example of the quartz crystal vibrating piece of this invention, (a) is the plane looked down on from the 1st surface side (upper side) of a vibration element. FIG. 4B is a front sectional view. It is a schematic diagram which shows the example of the electronic device carrying the vibration element as a quartz crystal vibrating piece of the said embodiment and a modification, a vibration gyro element, or a gyro sensor, (a) is a perspective view of a digital video camera, (b) is a perspective view of a mobile phone, (c) is a perspective view of a personal digital assistant (PDA).

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings.

(First embodiment)
(Vibration element)
FIG. 1 is a schematic diagram illustrating a schematic configuration of an embodiment of a tuning-fork type vibration element as a quartz crystal vibrating piece, and FIG. 1A is a first surface side (upper side) of a vibration unit having a groove opening. (B) is an AA line sectional view of (a).

As shown in FIG. 1, the vibration element 20 is formed using quartz as a base material (material constituting a main part). The crystal has an X axis called an electric axis, a Y axis called a mechanical axis, and a Z axis called an optical axis.
The vibration element 20 is cut out along a plane defined by the X-axis and the Y-axis orthogonal to the quartz crystal axis and processed into a flat plate shape, and has a predetermined thickness in the Z-axis direction orthogonal to the plane. Yes. The predetermined thickness is appropriately set depending on the oscillation frequency (resonance frequency), the outer size, workability, and the like.

Further, the flat plate forming the vibration element 20 can tolerate errors in the angle of cut-out from the quartz crystal in a certain range for each of the X axis, the Y axis, and the Z axis. For example, it is possible to use what is cut out by rotating in the range of 0 to 2 degrees around the X axis. The same applies to the Y axis and the Z axis.
The outer shape of the vibration element 20 is formed by wet etching using a photolithography technique. Note that a plurality of the vibration elements 20 can be taken out from one crystal wafer.

As shown in FIG. 1A, the vibration element 20 of the present embodiment extends in parallel with each other along the Y axis from the base 21 and one end of the base 21 (the Y-axis side end in the present embodiment). This is a so-called tuning-fork type crystal vibrating piece provided with the vibrating arms 22 and 23 as a pair of vibrating parts.
The vibrating arms 22 and 23 are provided with grooves 2 and 3, respectively.

Of the pair of vibrating arms 22 and 23, the groove 2 of one vibrating arm 22 has an opening on the first surface 1 a of the vibrating arm 22. The groove 2 has a virtual line P2 passing through the center of the opening on the first surface 1a of the vibrating arm 22 and along the extending direction of the vibrating arm 22, and the center of gravity of the vibrating arm 22 before the groove 2 is formed. It is disposed and provided at a position shifted by a predetermined amount in any direction (in this embodiment, the −X direction) parallel to the virtual line P <b> 1 that passes through and extends along the extending direction of the vibrating arm 22. The opening of the groove 2 is formed in an area on the left side in the figure when the vibrating arm 22 is divided in the width direction along the line P1.
Similarly, the groove 3 of the other vibrating arm 23 also has an opening on the first surface 1a of the vibrating arm 23, passes through the center of the opening on the first surface 1a of the vibrating arm 23, and vibrates. A virtual line (not shown) along the extending direction of the arm 23 passes through the center of gravity of the vibrating arm 23 before the groove 3 is formed and is a virtual line (not shown) along the extending direction of the vibrating arm 23. It is arranged and provided at a position shifted by a predetermined amount in a direction parallel to the direction. The opening of the groove 3 is the left side in the figure when the vibrating arm 23 is divided in the width direction by an imaginary line passing through the center of gravity of the vibrating arm 23 before the groove 3 is formed and along the extending direction of the vibrating arm 23. Is formed in the area.
As described above, it can be said that the openings of the grooves 2 and 3 described above are formed so as to be shifted to one side of the side surfaces on both sides of the first surface 1a when viewed in a plan view from the Z direction.
As shown in FIG. 1B, in the quartz substrate of the Z plate, the vibrating arms 22 and 23 are both substantially vertical on the −X side, but the + X side is compared to the −X side. It has a slope, and the inclination angle becomes gentler toward the -Y side. Here, considering the state in which the groove 2 is not formed, since the cross section of the vibrating arm has a width in the X direction that increases toward the −Z side, the −Z side of the vibrating arm has higher rigidity than the + Z side. . Therefore, for example, when the vibrating arm 22 vibrates in the −X direction and the vibrating arm 23 vibrates in the + X direction, the vibrating arms 22 and 23 add the vibration component in the + Z direction to the vibration component in the X direction, and the diagonally upward direction. Vibrate. As described above, when a vibration component (Z direction) other than the desired vibration direction (X direction) is applied, the vibration characteristics deteriorate or, for example, when configured as a gyro sensor, a physical quantity is not added due to an unnecessary vibration component. However, there is a possibility of erroneous detection in which a physical quantity is detected.
The inventor of the present application is effective to adjust the position of the grooves provided in the vibrating portions (vibrating arms 22 and 23) as means for suppressing the deterioration of the vibration of the vibrating arms due to the etching anisotropy of the crystal wafer. I found. That is, according to the degree to which the cross-sectional shape of the vibration part becomes asymmetrical, the first surface of the vibration part having the groove opening part passes through the center of the groove opening part and along the extending direction of the vibration part. The imaginary line is disposed at a position shifted by a predetermined amount in any direction parallel to the imaginary line passing through the center of gravity of the vibrating part before the groove is formed and along the extending direction of the vibrating part. The inventors have found that by providing the groove, it is possible to suppress deterioration in detection accuracy and temperature characteristics due to the cross-sectional shape of the vibration part being asymmetric.
The grooves 2 and 3 are formed on the side surface (−X side) opposite to the side surface (+ X side) having a gentle inclination angle. By forming the grooves 2 and 3 at such positions, for example, when the vibrating arm 22 vibrates in the −X direction and the vibrating arm 23 vibrates in the + X direction, a moment is generated in the −Z direction by the grooves 2 and 3. It is possible to cancel unnecessary vibration components in the + Z direction.

  Further, in each of the vibrating arms 22 and 23, the depth of the grooves 2 and 3 is half of the thickness from the first surfaces 1a and 1a of the vibrating arms 22 and 23 to the second surfaces 1b and 1b on the opposite side. It is deeper than. The shape in which the grooves 2 and 3 are deeper than half the thickness of each of the vibrating arms 22 and 23 is caused by a method for manufacturing the vibrating element 20 described later. That is, the outer shapes of the vibrating arms 22 and 23 and the grooves 2 and 3 are exposed simultaneously, and then the outer shapes of the vibrating arms 22 and 23 penetrating in the thickness direction of the quartz wafer and the grooves 2 and 3 are simultaneously etched. Therefore, the bottom surfaces of the grooves 2 and 3 reach the deep positions of the vibrating arms 22 and 23. By forming the grooves 2 and 3 deeply in this way, unnecessary vibration components (for example, the Z direction) other than the desired vibration directions (for example, the X-axis direction) of the vibrating arms 22 and 23 can be significantly suppressed. it can.

  An excitation (driving) electrode and a detection electrode are formed on the first surface 1 a of each vibrating arm 22, 23 of the vibrating element 20. In the vibration element 20 of the present embodiment, an excitation electrode 12 to which an excitation signal for exciting one vibration arm 22 is applied and an excitation electrode 13 to which an excitation signal for exciting the other vibration arm 23 is applied are provided. ing. In the present embodiment, each electrode is formed to extend to the inner walls of the grooves 2 and 3. Specifically, the excitation electrode 12 provided on the first surface 1 a of one vibrating arm 22 is also formed on the inner wall of the groove 2 and the excitation electrode provided on the first surface 1 a of the other vibrating arm 23. The working electrode 13 is also formed on the inner wall of the groove 3. The grooves 2 and 3 provided in the vibrating arms 22 and 23 have the effect of promoting the vibration by reducing the rigidity of the vibrating arms 22 and 23, and are used for exciting the inner walls (side surfaces and bottom surfaces) of the grooves 2 and 3. The provision of the electrodes 12 and 13 improves the electric field efficiency, and the CI value can be significantly reduced by these effects.

  The excitation electrodes 12 and 13 provided on the vibrating arms 22 and 23 are electrically connected to external connection terminals 15 and 16 provided on the base 21 and used for electrical connection with an external substrate. In the present embodiment, the excitation electrode 12 provided on the first surface 1 a of one vibrating arm 22 is connected to the external connection terminal 15 via a part of the base 21 and the side surface of the other vibrating arm 23. The excitation electrode 13 provided on the first surface 1 a of the other vibrating arm 23 is connected to the external connection terminal 16 via a part of the base 21 and the side surface of the one vibrating arm 22.

[Manufacturing method of vibration element]
Next, a method for manufacturing the resonator element 20 as the quartz crystal resonator element of the above embodiment will be described.
FIG. 2 is a flowchart showing a method for manufacturing the vibration element. FIGS. 3A to 3C and FIGS. 4A to 4D are front sectional views schematically showing the manufacturing process of the vibration part of the vibration element.
Usually, in the method of manufacturing a vibration element, a method is adopted in which a plurality of vibration elements are arranged in a plan view on a quartz wafer and then a plurality of vibration elements are obtained in a lump by dicing. 3 and 4 are front sectional views showing a part where a vibrating arm of one vibrating element is formed on a quartz wafer.

In the manufacturing method of the resonator element 20 of the present embodiment, first, as shown in FIG. 3A, a quartz crystal wafer 1 having an area where a plurality of resonator elements 20 can be formed (only a part of the crystal wafer 1 is shown in the drawing). Metal corrosion resistant films 120a and 120b are formed on the first surface 1a and the second surface 1b (shown) by sputtering, vapor deposition, or plating (step S1 in FIG. 2). As the metal corrosion-resistant films 120a and 120b, those having corrosion resistance against an etching solution used in a process of etching a crystal wafer described later are used. For example, a laminated film of chromium (Cr) as an underlayer and gold (Au) as an upper layer Can be used.
Further, photoresist films 131a and 131b are formed on the metal corrosion resistant films 120a and 120b by spin coating or the like (step S2 in FIG. 2).

  Next, as shown in FIG. 3B, only the outer surface of the base portion 21 and the vibrating arms 22 and 23 of the vibrating element 20 and the positive image of the groove (see FIG. 1) are provided only on the photoresist film 131a side of the first surface 1a. Alternatively, the external shape / groove pattern exposure is performed using the photomask 150 on which a negative pattern is drawn. In this embodiment, an example in which a positive photoresist film 131a is exposed using a so-called positive photomask 150 on which a positive pattern of the vibration element 20 is drawn is shown. That is, on the photomask 150, the outer shape of the vibrating arm 22 and the exposure pattern 152 of the groove 2, the outer shape of the vibrating arm 23 and the exposure pattern 153 of the groove 3, and the exposure pattern (not shown) of the outer shape of the base 21 are drawn. Then, these exposure patterns block the exposure light indicated by the downward arrows in the figure, and the exposure light transmitted through the other parts reaches the photoresist film 131a and is exposed (step S3 in FIG. 2).

Next, as shown in FIG. 3C, the exposed photoresist film 131a is developed to obtain development patterns 132 and 133 (step S4 in FIG. 2).
Next, the metal corrosion-resistant film 120a is etched using the developed patterns 132 and 133 obtained by development as a mask (step S5 in FIG. 2), and then the developed patterns 132 and 133 and the photoresist film of the photoresist film 131a are etched. As shown in FIG. 4A, the metal corrosion resistant film 120b is exposed on the second surface 1b side and the metal corrosion resistant film 120a is exposed on the first surface 1a side. Etching masks 122a and 123a are obtained.

Next, the quartz wafer 1 on which the metal corrosion-resistant film 120b and the etching masks 122a and 123a of the metal corrosion-resistant film 120a are formed is dipped in an etching solution containing hydrofluoric acid and wet-etched, whereby the metal corrosion-resistant film 120b and the etching mask 122a. , 123a is melted, and the outer shape / groove etching is performed to form the outer shape of the vibration element 20 (vibrating arms 22, 23 and the base 21) and the grooves 2, 3 (step of FIG. 2). S7). As a result, as shown in FIG. 4 (b), openings are formed on the first surfaces 1 a of the vibrating arms 22, 23 simultaneously with the vibrating arms 22, 23 and the base 21 (not shown) forming the outer shape of the vibrating element 20. Grooves 2 and 3 are formed.
In the process of simultaneously forming the outer shape of the vibrating arms 22 and 23 and the respective grooves 2 and 3 by crystal etching, the portions where the grooves 2 and 3 of the crystal wafer 1 are formed are the portions of the vibrating arms 22 and 23 and the base 21. Since the area in contact with the etching solution is small as compared with the portion where the outer shape is formed, the etching speed becomes slower as compared with the outer portion as the etching time becomes longer. Therefore, before the outer shapes such as the vibrating arms 22 and 23 are formed. The crystal in the grooves 2 and 3 does not penetrate into the groove. However, since the outer shape of the vibrating arms 22 and 23 and the grooves 2 and 3 are formed by etching simultaneously, the depth of each of the grooves 2 and 3 is changed from the first surface 1a of the vibrating arms 22 and 23 to the second. It is formed deeper than half of the thickness up to the surface 1b.

As shown in FIG. 4B, the cross-sectional shapes of the vibrating arms 22 and 23 are portions where the etching rate varies depending on the direction of the crystal due to the etching anisotropy of the crystal, and the etching rate is slow (right side in the figure). Etching residue is generated on the lower side) and is asymmetrical. When the cross-sectional shape is asymmetric in this way, the vibrating arms 22 and 23 generate vibrations that are different from the vibrations in the originally desired direction, causing leakage vibrations, resulting in deterioration of temperature characteristics without obtaining desired vibration characteristics, Due to the deviation of the driving vibration (excitation vibration) direction, the vibrating arms 22 and 23 vibrate in the detection direction (out-of-plane direction) in spite of the state where the rotational angular velocity is zero, thereby degrading the rotational angular velocity detection accuracy. There is a risk of malfunction. For this reason, it is preferable to perform the etching slightly slightly so that the etching residue of the crystal direction portion where the etching rate of the crystal wafer is slow is reduced as much as possible.
In order to suppress such problems due to the asymmetric cross-sectional shape of the vibrating arms 22 and 23, in the vibrating element 20 of the present embodiment, the positions of the grooves 2 and 3 provided in the vibrating arms 22 and 23 are adjusted. Yes. That is, as described above, the grooves 2 and 3 of the vibrating arm arms 22 and 23 pass through the center of the opening on the first surface 1a of the vibrating arms 22 and 23 and extend in the extending direction of the vibrating arms 22 and 23. An imaginary line (P2 in FIG. 1A) passes through the center of gravity of each of the vibrating arms 22 and 23 before the grooves 2 and 3 are formed, and extends along the extending direction of the vibrating arms 22 and 23. Is disposed at a position shifted by a predetermined amount in a direction parallel to the line (P1). Here, the predetermined amount of “position shifted by a predetermined amount” means that each of the vibrating arms 22 and 23 that can be predicted by defining the crystal axis of the crystal wafer and forming the outer shape of the resonator element 20 by wet etching. This means an amount (position) that can be set in advance as the position of the grooves 2 and 3 that can suppress leakage vibration.
In the present embodiment, the outer shape of the vibrating arms 22 and 23 and the grooves 2 and 3 are formed by exposing them simultaneously using the same photomask 150. Therefore, the etched vibrating arms 22 and 23 and the grooves 2 and 3 It is possible to adjust the position of the film with good reproducibility.

  After the outer shapes of the vibrating arms 22 and 23 and the grooves 2 and 3 are etched, the metal corrosion resistant film 120b and the etching masks 122a and 123a of the metal corrosion resistant film are peeled off by immersing the crystal wafer in a mixed acid solution or the like. Next, as shown in FIG. 4C, metallizing masks 136a and 136b and metallizing masks 137a and 137b are formed (step S9 in FIG. 2). The metalizing masks 136a, 136b, 137a, and 137b can be formed by, for example, patterning a photoresist by photolithography.

Next, using the metallizing masks 136a, 136b, 137a, 137b as masks, various electrodes are formed by laminating electrode films on the quartz surface exposed from the masks by a method such as sputtering or vapor deposition (steps in FIG. 2). S10). In FIG. 4D, the excitation electrode 12 is formed on the first surface 1 a of the vibrating arm 22 and the inner wall of the groove 2, and the excitation electrode is formed on the first surface 1 a of the vibrating arm 23 and the inner wall of the groove 3. 13 is formed, and excitation electrodes 13 or excitation electrodes 12 as lead-out electrodes are formed on the side surfaces of the respective vibrating arms 22 and 23.
As described above, a series of manufacturing steps of the vibration element 20 is completed through the steps described above.
Note that a large number of vibration elements 20 formed on the quartz wafer 1 vertically and horizontally can be provided as a single piece by a method such as dicing.

According to the above embodiment, the vibration part and the groove of the vibration element 20 are simultaneously exposed using the same photomask 150. Therefore, it is possible to add high-performance equipment such as an aligner with high positional accuracy and increase the manufacturing process. Without making it possible, the outer shape of the vibrating arms 22 and 23 and the grooves 2 and 3 with respect thereto can be formed by accurately adjusting the positions in a desired positional relationship. Therefore, it is possible to effectively suppress deterioration of vibration characteristics and temperature characteristics due to the etching anisotropy of the quartz wafer, and it is possible to provide a vibration element having stable vibration characteristics at a low cost.
Further, after the crystal wafer 1 is etched to form the outer shape of the vibration part, a method of adjusting the position of the groove according to the degree of cross-sectional shape of the vibration part becomes asymmetric (a method of performing the outer shape formation and the groove formation separately) ), There is a problem that the manufacturing efficiency is remarkably lowered because it is necessary to measure the shape and frequency characteristics of the vibrating part for each vibrating gyro element (quartz crystal vibrating piece). If the vibration part and the groove of the vibration element 20 are simultaneously exposed using the same photomask 150 and are etched at the same time, the outer shape of the vibration arms 22 and 23 and the grooves 2 and 3 with respect to the outer shape and the grooves 2 and 3 are in a desired positional relationship. Therefore, it is not necessary to make adjustments for each piece.
Further, according to the manufacturing method of the above embodiment, it is possible to relatively easily cope with the downsizing of the vibration element (quartz crystal vibrating piece).

  The vibration element 20 and the manufacturing method thereof described in the above embodiment can be implemented as the following modifications.

Hereinafter, a modification of the method for manufacturing a vibration element will be described with reference to the drawings.
(Modification 1)
FIG. 5 is a flowchart showing a first modification of the method for manufacturing a vibration element. 6A to 6D are front cross-sectional views schematically showing the manufacturing process of the vibration part in the first modification of the method for manufacturing a vibration element. In addition, about the common part with the said embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted and it demonstrates centering on a different structure from the said embodiment.

In the manufacturing method of the vibration element of the present modification shown in FIG. 5, the etching mask formation from step S11 to step S16 is performed with the same configuration as steps S1 to S6 in FIG. Can do. That is, the metal corrosion-resistant film 120b is formed on the second surface 1b side of the crystal wafer 1 as shown in FIG. 6A through the process from the formation of the metal corrosion-resistant film in step S11 to the removal of the photoresist in step S16. Etching masks 122a and 123a made of metal corrosion resistant films are formed on the first surface 1a side.
However, in the method for manufacturing the vibration element according to the present modification, as described later, after the etching process for forming the outer shape and the groove of the vibration element, there is a process of half-etching the entire second surface 1b side of the crystal wafer. Therefore, a quartz wafer 1 ′ having a thickness thicker than the thickness of the vibration element to be manufactured by the half etching is used.

  Next, etching is performed by immersing the quartz wafer 1 'on which the metal corrosion resistant film 120b and the metal corrosion resistant etching masks 122a and 123a are formed in an etching solution containing hydrofluoric acid, as shown in FIG. The outer shape of the vibrating elements such as the vibrating arms 22 'and 23' and the grooves 202 and 203 are formed at the same time (step S17 in FIG. 5). However, of the outer shape of the vibration element, the thickness from the first surface 1a to the second surface 1b of the crystal wafer 1 ′ is further etched and thinned in a subsequent process.

  Next, of the metal corrosion resistant film 120b and the metal corrosion resistant film etching masks 122a and 123a, only the metal corrosion resistant film (back surface etching mask) 120b on the second surface 2b is removed (step S18 in FIG. 5). Here, if necessary, a process of covering the crystal surface exposed on the first surface 1a side with an etching mask material is performed. When the step of covering the first surface 1a side with an etching mask material is performed, the etching masks 122a and 123a of the metal corrosion resistant film may be peeled off together with the metal corrosion resistant film 120b at step S18.

Next, as shown in FIG. 6C, back surface etching is performed to etch the entire surface of the second surface 1b of the vibrating arms 22 ′ and 23 ′ by a predetermined amount (step S19 in FIG. 5), and then the etching mask 122a. , 123a is peeled off (step S20 in FIG. 5), and as shown in FIG. 6D, the outer shape including the grooves 202, 203 of the vibration element 220 according to the manufacturing method of this modification is completed. .
Next, after forming the metalizing mask shown in step S21 of FIG. 5, various electrodes are formed by laminating electrode films using the metalizing mask as a mask (step S22 of FIG. 5), and a series of vibrations The manufacturing process of the element 220 ends.

  According to the method for manufacturing the vibration element of the first modification, the back surface etching step (step S19 in FIG. 5) causes the etching to occur at a deep etching position, that is, on the second surface 1b side due to the crystal etching anisotropy. It is possible to remove at least a part of the etching residue (fin). Therefore, by simultaneously exposing and patterning the vibrating arms 22 'and 23' and the grooves 202 and 203, the positions of the grooves 202 and 203 are adjusted accurately, and the vibration characteristics are deteriorated due to the crystal etching anisotropy. Since the degree of cross-sectional shape of the vibrating arms 22 ′ and 23 ′ becomes asymmetrical is reduced, the vibrating element 220 with high detection sensitivity that maintains stable vibration characteristics can be provided.

(Modification 2)
Next, a second modification of the method for manufacturing a vibration element will be described.
FIG. 7 is a flowchart showing a second modification of the method for manufacturing a vibration element. FIGS. 8A to 8C and FIGS. 9A to 9D are front sectional views schematically showing the manufacturing process of the vibration part in the modified example 2 of the method for manufacturing a vibration element. In addition, about the common part with the said embodiment and the modification 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

First, as shown in FIG. 8A, metal corrosion-resistant films 120a and 120b are formed on the first surface 1a and the second surface 1b of the quartz crystal wafer 1 ″ thicker than the thickness of the vibration element manufactured by the present manufacturing method. Is formed (step S31 in FIG. 7).
Next, photoresist films 131a and 131b are formed on the metal corrosion resistant films 120a and 120b (step S32 in FIG. 7).

  Next, as shown in FIG. 8B, the outer shape and the groove pattern are exposed on the photoresist films 131a and 131b on the first surface 1a side and the second surface 1b side of the quartz wafer 1 ''. Double-sided exposure is performed (step S33 in FIG. 7). At this time, for the exposure on the first surface 1a side, the surface photomask 250A on which the outer shape of the vibration element such as a vibrating arm and the exposure patterns 252a and 253a of the grooves are drawn is used. For exposure, exposure is performed using a back surface photomask 250B on which exposure patterns 252b and 253b of vibrating elements such as vibrating arms are drawn.

Next, as shown in FIG. 8C, the exposed photoresist films 131a and 131b are developed to obtain development patterns 132a and 133a on the first surface 1a side, and on the second surface 1b side. After obtaining the development patterns 132b and 133b (step S34 in FIG. 7), the metal corrosion resistant film 120a and the metal corrosion resistant film 120b are etched using the development patterns 132a and 133a and the development patterns 132b and 133b as masks (step in FIG. 7). S35).
Next, the development patterns 132a, 133a, 132b, and 133b of the photoresist films 131a and 131b are peeled off (step S36 in FIG. 7), so that a metal is formed on the first surface 1a side as shown in FIG. 9A. The etching masks 122a and 123a for the corrosion resistant film 120a are obtained, and the etching masks 122b and 123b for the metal corrosion resistant film 120b are obtained on the second surface 1b side.

Next, the crystal wafer 1 ″ in which the etching masks 122a and 123a made of the metal corrosion resistant film 120a are formed on the first surface 1a side and the etching masks 122b and 123b made of the metal corrosion resistant film 120b are formed on the second surface 1b side. Is immersed in an etching solution containing hydrofluoric acid to perform double-sided etching. As a result, as shown in FIG. 9B, the outer shape of the vibrating elements such as the vibrating arms 22 ″ and 23 ″ and the grooves 302 and 303 of the vibrating arms 22 ″ and 23 ″ are simultaneously formed. (Step S37 in FIG. 7).
The cross-sectional shape of the vibrating arms 22 ″ and 23 ″ formed by the double-sided etching is compared with that of the vibrating arms formed by single-sided etching only from the first surface 1a side as in the above-described embodiment and modification 1. Thus, the etching residue in the crystal direction in which etching residue tends to occur is reduced.

Next, of the etching masks 122a and 123a on the first surface 1a side and the etching masks 122b and 123b on the second surface 1b side, at least the etching masks 122b and 123b on the second surface 1b side are stripped (FIG. 7). Step S38).
Next, as shown in FIG. 9C, back surface etching is performed to etch the entire surface of the second surface 1b of the vibrating arms 22 ″, 23 ″ by a predetermined amount (step S39 in FIG. 7). Surface etching mask peeling is performed to peel the etching masks 122a and 123a on the first surface 1a side (step S40 in FIG. 7). As a result, as shown in FIG. 9D, the outer shape including the grooves 302 and 303 of the vibration element 320 by the manufacturing method of Modification 2 is completed.
Next, after forming the metalizing mask shown in step S41 in FIG. 7, various electrodes are formed by laminating electrode films using the metalizing mask as a mask (step S42 in FIG. 7). The manufacturing process of the vibration element 320 of Example 2 is completed.

According to the method of manufacturing the vibration element of the second modification, the outer shape of the vibration element 320 such as the vibration arms 22 ″ and 23 ″ and the grooves 302 and 303 of the vibration arms 22 ″ and 23 ″ are simultaneously formed. Since the etching is performed from both the first surface 1a and the second surface 1b of the crystal wafer 1 ″ when forming, the etching residue due to the crystal etching anisotropy is reduced.
In addition, in the manufacturing method of the second modification, after the outer shape / groove pattern (both sides) etching step, back surface etching (step S39 in FIG. 7) is performed, so that etching remains (fins) from the second surface 1b side. At least part of it has been removed. As a result, the left-right asymmetry of the cross-sectional shapes of the vibrating arms 22 ″, 23 ″ is further eliminated, so that the deterioration of the vibration characteristics due to the crystal etching anisotropy can be further reduced.

  As described above, the tuning fork type vibration element 20 as one embodiment of the quartz crystal vibrating piece has been described with reference to FIGS. 1 to 9. Since the coupling with the vibration mode is reduced, there is also a secondary effect that the frequency temperature characteristic is improved. For example, when the desired vibration component is the X direction and the unnecessary vibration component is the Z direction, the frequency temperature characteristic of the Z direction vibration is not mixed with the frequency temperature characteristic of the X direction vibration, thereby improving the frequency temperature characteristic. Is possible. In addition, since unnecessary vibration can be suppressed, the CI value (crystal impedance value) can be reduced, thereby providing a secondary effect that the Q value can be increased.

(Modification 3)
[Vibrating gyro element]
Next, a vibrating gyro element as a modification of the quartz crystal vibrating piece of the present invention will be described with reference to the drawings.
FIG. 10 schematically shows a tuning fork-type vibrating gyro element as a quartz crystal vibrating piece, in which (a) is a plan view and (b) is a sectional view taken along line BB of (a). In the configuration of the vibrating gyro element of this modification, the cross-sectional shape of the vibrating arms 122 and 123 as the vibrating portion and the shape of the groove 102 provided in the vibrating arm 122 are the vibrating arms of the vibrating element 20 of the above embodiment. Since it is the same as the shape of 22 and 23, detailed description is abbreviate | omitted.
As shown in FIG. 10A, the vibrating gyro element 120 includes a base 121 and a pair of vibrating arms 122 extending in parallel with each other from one end of the base 121, like the vibrating element 20 of the first embodiment. , 123 and so-called tuning fork shape.
One vibration arm 122 of the pair of vibration arms 122 and 123 is provided with a groove 102.

  The groove 102 has an opening on the first surface 101 a of the vibrating arm 122. In the groove 102, the virtual line P <b> 2 that passes through the center of the opening on the first surface 101 a of the vibrating arm 122 and extends in the extending direction of the vibrating arm 122 indicates the center of gravity of the vibrating arm 122 before the groove 102 is formed. It is disposed and provided at a position shifted by a predetermined amount in any direction (−X direction in this modified example) parallel to the virtual line P <b> 1 that passes through and extends along the extending direction of the vibrating arm 122. The opening of the groove 102 is formed in an area on the left side in the figure when the vibrating arm 122 is divided in the width direction along the line P1.

One vibrating arm of the pair of vibrating arms 122 and 123 is provided with an excitation (driving) electrode, and the other vibrating arm is formed with a detection electrode. In the vibrating gyro element 120 of this modification, as shown in FIG. 10B, an excitation electrode 112 is provided on one vibrating arm 122, and a detection electrode 113 is provided on the other vibrating arm 123.
By applying an electrical signal ± V to the excitation electrode 112, the vibrating arm 122 is excited and mechanically vibrates in the in-plane direction (± X direction) of the first surface 101a.
Further, the detection electrode 113 can convert the mechanical vibration of the vibrating arm 123 into an electric detection completed signal.

  The excitation electrode 112 provided on the vibrating arm 122 is electrically connected to the external connection terminal 116 provided on the base 121. The detection electrode 113 provided on the vibrating arm 123 is electrically connected to the external connection terminal 115 provided on the base 121.

  In the tuning fork type vibration gyro element 120 having the above-described configuration, an excitation electric signal (excitation signal) ± V is applied to the excitation electrode 112 and the vibrating arm 122 vibrates in the ± X direction based on the principle of the tuning fork type gyrometer. When the vibrating gyro element 120 rotates around the Y axis, the rotational motion generates a Coriolis force perpendicular to the vibration direction of the vibrating arm 122, and as a result, in a plane perpendicular to the plane of the excitation vibration. At least vibration in the ± Z direction of the vibrating arm 123 for detection is generated. This mechanical vibration is converted into an electric signal by the piezoelectric quartz crystal of the vibrating gyro element 120, and this electric signal is detected by the detection electrode 113 provided on the surface of the vibrating arm 123 for detection.

  As described above, according to the vibration gyro element 120 having the configuration described above, one of the vibration arms 122 and 123 as a pair of vibration parts is used as the vibration part for excitation, and the other vibration arm 123 is used as the vibration part. Since it is used as a vibration part for detection, the excitation electrode 112 of the vibration arm 122 and the detection electrode 113 of the vibration arm 123 can be arranged separately. This facilitates the electrode wiring of the vibrating gyro element 120 including the excitation electrode 112 and the detection electrode 113, and the capacitance between the electrode wirings that can occur when the excitation electrode 112 and the detection electrode 113 are close to each other. Binding can be suppressed. Therefore, it is possible to provide the vibrating gyro element 120 that detects a physical quantity such as a rotational angular velocity with high accuracy.

The tuning fork-type vibrating gyro element is configured such that one of the pair of vibrating arms 122 and 123 is a driving vibrating arm 122 and the other is a detecting vibrating arm 123 like the vibrating gyro element 120 described above. However, it is not limited to this. A driving electrode and a detection electrode are provided on each of the pair of vibrating arms, and an excitation signal is applied to the driving electrode to drive both vibrating arms and to drive (vibrate) both vibrating arms. It is also possible to detect the Coriolis force generated when the rotational angular velocity is applied to the vibrating gyro element in a state of being detected by the detection electrode.
In this configuration, the arrangement of the electrodes provided on each vibrating arm is different from that of the vibrating gyro element 120 of the third modification.
More specifically, excitation electrodes are provided on both main surfaces on the base side of each vibrating arm so that the polarities are the same at a certain moment. Here, one vibrating arm and the other vibrating arm are arranged so that the polarities are reversed at a certain moment. For example, when the polarity of an excitation electrode provided on both main surfaces of one vibrating arm is +, the polarity of the excitation electrode provided on both main surfaces of the other vibrating arm is set to −.
In addition, excitation electrodes having opposite polarities to the instantaneous polarity of the excitation electrodes provided on both main surfaces of each vibrating arm are provided on both side surfaces that are orthogonal to and opposite to both main surfaces of each vibrating arm. For example, the polarity of the excitation electrode provided on both side surfaces of one vibrating arm is negative with respect to the momentary polarity of the excitation electrodes on both main surfaces of the vibrating arm, and the excitation provided on both side surfaces of the other vibrating arm. The electrode is set to +.
With the electrode configuration as described above, at one moment, an electric field is generated in one vibrating arm in the direction from the center of the vibrating arm to both side surfaces, and the other vibrating arm is moved from the both side surfaces of the vibrating arm to the center. An electric field is generated in the direction of.

  In addition, a pair of detection electrodes arranged in parallel along the extending direction of each vibrating arm on each main surface is provided on both main surfaces on the distal end side of each vibrating arm. Here, the pair of detection electrodes on each main surface of each vibrating arm is provided so as to have different polarities at a certain moment. Further, the polarity at a certain moment of the pair of detection electrodes provided on both main surfaces of each vibrating arm is arranged to be opposite to the polarity at the moment of the opposing detection electrode. For example, when a pair of detection electrodes including a first detection electrode having a positive polarity and a second detection electrode having a negative polarity at a certain moment are provided on one main surface of the vibrating arm, The polarity of each of the third detection electrode facing the first detection electrode and the fourth detection electrode facing the second detection electrode is such that the third detection electrode is negative and the fourth detection electrode is negative. Arrange so that the electrode is positive.

In the vibration gyro element having the above-described configuration, by applying an electric field through each excitation electrode, each vibration arm gives a bending vibration in a direction along the main surfaces (in-plane direction, Y direction in the figure). When each vibrating arm is performing bending vibration in the in-plane direction, when the angular velocity ω is applied around the axis along the extending direction of the vibrating arm, the Coriolis force causes the orthogonal to the in-plane direction. A new bending vibration occurs in the out-of-plane direction. By detecting the voltage generated by this new bending vibration with the detection electrodes provided on both main surfaces of each vibrating arm, the value of the angular velocity ω applied to the vibrating gyro element can be known.
Also in the vibration gyro element having the above-described configuration, by providing the groove 2, 3 or the groove 102 having the same structure as the vibration gyro element 20 of the above-described embodiment or the vibration gyro element 120 of the third modification, It is possible to cancel unnecessary vibration components caused by the cross-sectional shape of the vibrating arm being asymmetrical, and to suppress deterioration in detection accuracy and temperature characteristics.
Further, while the vibrating gyro element 120 of the above modification 3 is driven by only one vibrating arm 122 of the pair of vibrating arms 122 and 123, by driving both vibrating arms, the excitation efficiency is improved. The CI value can be reduced and the consumption current can be suppressed accordingly.

(Modification 4)
In the embodiment and the third modification, the tuning fork type vibration element 20 and the vibration gyro element 120 have been described as the crystal vibrating piece. However, the shape of the crystal vibrating piece is not limited thereto. Next, an example of a crystal vibrating piece having a shape different from the tuning fork type will be described.
FIG. 11 is a schematic plan view for explaining a vibrating gyro element as an H-type crystal vibrating piece having a configuration in which a pair of vibrating portions extend from one end of a base and the other end opposite to the one end. FIG. 12 is a schematic plan view showing a vibrating gyro element as a tripod-type quartz vibrating piece having three vibrating portions extending from one end of the base portion.

First, a crystal vibrating piece having an outer shape of H type will be described.
A vibrating gyro element 420 as a crystal vibrating piece shown in FIG. 11 includes a pair of vibrating arms 422 and 423 as a pair of vibrating portions extending in parallel with each other from one end of a base portion 421 and a pair of vibrating portions extending in the opposite side. The detection vibrating arms 424 and 425 are provided. Of these, grooves 402 and 403 are formed on the main surfaces of the pair of drive vibrating arms 422 and 423 in the longitudinal direction of the drive vibrating arms 422 and 423. The grooves 402 and 403 have openings on the first surfaces 401a of the driving vibrating arms 422 and 423, respectively. The groove 402 passes through the center of the opening on the first surface 401a of the driving vibration arm 422, and the virtual line P2 along the extending direction of the driving vibration arm 422 is formed before the groove 402 is formed. A position shifted by a predetermined amount in any direction (−X direction in this modification) passing through the center of gravity of the driving vibrating arm 422 and parallel to the virtual line P1 along the extending direction of the driving vibrating arm 422 It is arranged and provided. The opening of the groove 402 is formed in an area on the left side in the figure when the driving vibrating arm 422 is divided in the width direction along the line P1. A groove 403 of the other driving vibrating arm 423 is formed in the same positional relationship.
Driving first electrodes 412 and 413 are provided on both main surfaces of the driving vibration arms 422 and 423 and on the side surfaces and bottom surface of the grooves 402 and 403 on one main surface, and on the side surfaces of the driving vibration arms 422 and 423. The drive second electrode (not shown) having a polarity different from that of the drive first electrode is provided at a certain moment to constitute a drive electrode that vibrates the vibration gyro element 420.

When a predetermined AC voltage is applied to the drive electrode, an electric field is alternately generated in a direction parallel to both main surfaces of the drive vibrating arms 422 and 423 as in the third modification, and the drive vibrating arms 422 and 423 Bends and vibrates in the same direction as
In this state, when the vibrating gyro element 420 rotates around the Y axis in the figure, the driving vibrating arms 422 and 423 are driven by the Coriolis force acting in the direction perpendicular to the vibration direction with respect to the rotational angular velocity ω. It receives stress in the Z axis direction and vibrates in the Z direction. This vibration causes the detection vibrating arms 424 and 425 to vibrate at the resonance frequency, which is detected by the detection electrodes 414 and 415 as electric signals, and the rotational angular velocity applied to the vibration gyro element 420 and the rotation direction thereof. Ask for.
Since the H-type vibrating gyro element such as the vibrating gyro element 420 is driven by the driving vibrating arms 422 and 423, the excitation efficiency is improved and the Cl value can be suppressed, and the driving vibrating arms 422 and 423 are detected. Since the vibrating arms 424 and 425 are extended from the opposite ends of the base 421, the drive electrode and the detection electrode can be easily separated, and the detection electrode can be made large, so that the detection sensitivity can be increased. Can be improved.

Next, as a second variation of this modification, a tripod type quartz crystal vibrating piece having a configuration in which three vibrating portions are extended from one end of the base will be described.
A vibrating gyro element 520 as a crystal vibrating piece shown in FIG. 12 has a base 521 and three vibrating arms 522, 523, and 524 extending in parallel with each other from one end of the base 521.

  Each of the driving vibrating arms 522 and 523 is provided with grooves 502 and 503 that are elongated along the extending direction of the vibrating arms 522 and 523. The grooves 502 and 503 have openings on the first surfaces 501a of the vibrating arms 522 and 523, pass through the centers of the openings on the first surfaces 501a of the vibrating arms 522 and 523, and each vibrating arm 522. The virtual line P2 along the extending direction of 523 passes through the center of gravity of the vibrating arms 522 and 523 before the grooves 502 and 503 are formed, and is relative to the virtual line P1 along the extending direction of the vibrating arms 522 and 523. Are disposed at positions shifted by a predetermined amount in either direction parallel to each other (−X direction in this modification). The openings of the grooves 502 and 503 are formed in the left area in the figure when the vibrating arms 522 and 523 are divided in the width direction along the line P1.

Of the three vibrating arms 522, 523, and 524, excitation electrodes 512 and 513 are provided on the vibrating arms 522 and 523 provided on both sides of the vibrating arm 524 therebetween, and these vibrating arms 522 and 523 are connected to each other. It is used as a driving vibrating arm (vibrating part).
A detection electrode 514 is formed on the vibration arm 524 arranged in the middle of the three vibration arms 522, 523, and 524, and the vibration arm 524 is used as a vibration arm (vibration unit) for detection. By applying an electric signal ± V to the excitation electrodes 512 and 513, the vibrating arms 522 and 523 are excited to mechanically vibrate in the in-plane direction (± X direction) of the first surface 501a, and are detected. The electrode 514 can convert the mechanical vibration of the vibrating arm 524 into an electrically detected signal.

  The usage of the three vibrating arms 522, 524, and 523 is not limited to this, and the electrodes may be formed so as to have two vibrating arms for driving and one vibrating arm for detection. For example, if electrodes are formed so that the adjacent vibrating arm 522 and the vibrating arm 524 can be used as a driving vibrating arm and the vibrating arm 523 adjacent to the vibrating arm 524 can be used as a detecting vibrating arm, the driving vibrating arm can be used. The Q value of the drive vibration is increased by the proximity of 522 and 524, whereby the Cl value of the drive vibration is reduced, and accordingly, the consumption current can be suppressed.

  As described above, in the configuration of the two vibrating gyro elements 420 and 520 of the modified example 4 described above, the vibrating element 20 of the above embodiment or the modified example is added to the driving vibrating arms 422 and 423 or the driving vibrating arms 522 and 523. By providing the grooves 402 and 403 or the grooves 502 and 503 having the same configuration as the grooves 2 and 3 of the vibration gyro element 3 or the grooves 102, the cross-sectional shape of the vibrating arm as the vibrating portion is asymmetric. Therefore, it is possible to provide the vibration gyro elements 420 and 520 having high sensitivity and stable detection accuracy by canceling unnecessary vibration components to suppress deterioration of detection accuracy and temperature characteristics.

(Second Embodiment)
[Gyro sensor]
Next, a gyro sensor equipped with the quartz crystal resonator element of the present invention will be described with reference to the drawings.
FIG. 13 is a schematic view showing a gyro sensor provided with the vibrating gyro element 120 described in Modification 3 as an example of the quartz crystal vibrating piece of the present invention. FIG. 13A is a first surface of the vibrating gyro element 120. The top view seen from 101a side (upper side) and (b) are front sectional views.
In FIG. 13A, the lid (lid body) is omitted for convenience. Moreover, about a common part with the said embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 13, the gyro sensor 100 includes a vibration gyro element 120 as a crystal vibrating piece, an IC chip 40 as a semiconductor circuit element having at least a drive circuit and a detection circuit for the vibration gyro element 120, and the vibration gyro element 120. And a package 60 for accommodating the IC chip 40.

  The package 60 is formed by laminating a flat first layer substrate 61, a rectangular annular second layer substrate 62, a third layer substrate 63, and a fourth layer substrate 64 having different opening sizes in this order. . Since the size of the opening increases as it goes upward from the second layer substrate 62 to the fourth layer substrate 64, a recess having a step is formed inside the package 60. In addition, as the first layer substrate 61 to the fourth layer substrate 64 constituting the package 60, a ceramic green sheet formed is widely used. For example, a sintered aluminum oxide sintered body is used.

The IC chip 40 is bonded and fixed to the upper surface of the first layer substrate 61 that becomes the concave bottom surface of the concave portion of the package 60 by a die attach material (not shown).
In the IC chip 40, an integrated circuit (not shown) including a semiconductor element such as a transistor or a memory element is formed on the active surface 40a side. This integrated circuit includes a driving circuit for driving and vibrating the vibrating gyro element 120 and a detecting circuit for detecting a detected vibration generated in the vibrating gyro element 120 when an angular velocity is applied. On the active surface 40a side of the IC chip 40, there are provided a plurality of electrode pads 45 that are drawn from the integrated circuit and make electrical connection between the integrated circuit and the outside.
Each electrode pad 45 of the IC chip 40 is electrically connected via a bonding wire 95 to a corresponding IC connection terminal 65 provided in a step formed by the second layer substrate 62 in the recess of the package 60. . The electrical connection between the IC chip 40 and the package 60 is not limited to the method using the wire bonding according to the present embodiment. For example, bumps such as solder are provided on the electrode pads 45 and are directly bonded to the IC connection terminals. Other bonding methods such as face-down bonding can be used.

A mount electrode 66 to which the vibrating gyro element 120 is bonded is provided at the step portion formed by the third layer substrate 63 in the recess of the package 60.
The vibration gyro element 120 is connected to the mount electrode 66 via a bonding member 97 such as a conductive adhesive in a state where the external connection terminals 115 and 116 provided on the base 121 are aligned with the corresponding mount electrode 66 of the package 60. It is joined. As a result, the vibrating gyro element 120 is cantilevered above the IC chip 40 through the gap in the recess of the package 60.
Note that electrodes and terminals such as IC connection terminals 65 and mount electrodes 66 provided in the package 60, and wirings for connecting them are made of, for example, nickel (Ni), gold (Au) on a metallized layer such as tungsten (W). The metal film which laminated | stacked each film, such as by plating etc., is used.

In the gyro sensor 100, the lid 70 is connected to the package 60 via a joining member 69 such as a seam ring or low-melting glass in a state where the IC chip 40 and the vibrating gyro element 120 are arranged and accommodated in the package 60 as described above. Bonded to the upper surface of For the lid 70, a metal such as Kovar, glass, ceramic or the like is used.
Thereby, the inside of the package 60 is hermetically sealed. Note that the inside of the package 60 is preferably maintained in a vacuum state (high vacuum state) or in an inert gas atmosphere so that the vibration of the vibrating gyro element 120 is not hindered.

  Since the gyro sensor 100 configured as described above includes the vibration gyro element 120 described in the above embodiment, mechanical coupling between driving vibration and detection vibration due to etching anisotropy of the crystal wafer is suppressed, Stable rotation angular velocity can be detected. Therefore, the gyro sensor 100 is preferably used for camera shake correction of an imaging device, posture detection of a vehicle or the like in a mobile navigation system using a GPS (Global Positioning System) satellite signal, posture control, and the like.

  In the present embodiment, the gyro sensor 100 including one set of the vibration gyro element 120 and the IC chip 40 that controls the vibration gyro element 120 has been described. However, by mounting a plurality of sets of vibration gyro elements and IC chips, for example, a plurality of axes A high-performance gyro sensor capable of detecting the rotational angular velocity of the direction can be provided.

(Third embodiment)
〔Electronics〕
As described above, the vibration element and the vibration gyro element as the quartz crystal resonator element described in the above embodiment and the modification, and the electronic device equipped with the gyro sensor according to the second embodiment including them increase the cost as described above. Since the vibration element and the vibration gyro element whose vibration characteristics are stabilized while being suppressed are provided, high performance and cost reduction can be achieved.
For example, FIG. 14A shows an application example to a digital video camera. The digital video camera 240 includes an image receiving unit 241, an operation unit 242, an audio input unit 243, and a display unit 1001. In such a digital video camera 240, for example, by mounting the gyro sensor 100 including the vibrating gyro element 120 of the above-described modification 3, a so-called camera shake correction function can be mounted.
FIG. 14B shows an application example to a mobile phone as an electronic apparatus, and FIG. 14C shows an application example to a personal digital assistant (PDA).
First, the cellular phone 3000 shown in FIG. 14B includes a plurality of operation buttons 3001, scroll buttons 3002, and a display unit 1002. By operating the scroll button 3002, the screen displayed on the display unit 1002 is scrolled.
The PDA 4000 shown in FIG. 14C includes a plurality of operation buttons 4001, a power switch 4002, and a display unit 1003. When the power switch 4002 is operated, various kinds of information such as an address book and a schedule book are displayed on the display unit 1003.
Various functions can be imparted by mounting the gyro sensor 100 including the vibration gyro element 120 of the modification 3 on the cellular phone 3000 or the PDA 4000. For example, when a camera function (not shown) is given to the mobile phone 3000 shown in FIG. 14B, camera shake correction can be performed by the vibration gyro element 120 and the gyro sensor 100 mounted on the mobile phone 3000. When the cellular phone 3000 of FIG. 14B or the PDA 4000 of FIG. 14C is equipped with a global positioning system widely known as GPS (Global Positioning System), the vibration element 20 of the above embodiment is provided. By mounting the gyro sensor 100, the position and orientation of the mobile phone 3000 and the PDA 4000 can be recognized in the GPS.

  Note that the present invention is not limited to the electronic device shown in FIG. 14, and the mobile device and the car navigation device are applicable to the vibration device 20, the vibration gyro device 120, and the gyro sensor 100 including the vibration gyro device 120 of the present invention. Electronic notebooks, calculators, workstations, videophones, POS terminals, game machines, and the like.

  Although the embodiments of the present invention made by the inventor have been specifically described above, the present invention is not limited to the above-described embodiments and modifications thereof, and various modifications can be made without departing from the spirit of the present invention. It is possible to make changes.

  For example, in the above embodiment and the modification, a tuning-fork type crystal having the vibrating arms 22 and 23 and the vibrating arms 122 and 123 as a pair of vibrating portions, such as the vibrating element 20 and the vibrating gyro elements 120, 420, and 520, etc. Although the vibration piece, the vibration gyro element 520 having the three vibration arms 522, 523, and 524 or the crystal vibration piece having the four vibration arms 422, 423, 424, and 425 such as the vibration gyro element 420 have been described, It is not limited to. For example, a beam-type crystal vibrating piece in which one vibrating part (vibrating arm) is extended from the base, a crystal vibrating piece having four or more vibrating parts, or a plurality of pairs of a single base via a beam or the like. According to the manufacturing method of forming the vibration part and the groove of the vibration part of the present invention by simultaneous exposure, even a crystal vibration piece (for example, a so-called double T-type crystal vibration piece) provided with the vibration part of FIG. The same effects as those described in the above-described embodiments and modifications can be obtained.

In the above embodiment and the modification, the excitation electrodes 12 and 13 on the first surface 1a of each vibration arm, for example, the vibration arms 22 and 23 of the vibration element 20 of the above embodiment, are respectively connected to the inner walls of the grooves 2 and 3. The configuration is also provided.
The present invention is not limited to this, and even when there is no electrode on the inner wall, it is possible to suppress the deterioration of the vibration characteristics described above.

  Although the present invention has been described using several embodiments, the present invention is not limited to these embodiments, and various modifications can be made without departing from the technical idea of the present invention. It can be easily understood by the contractor. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings.

In each of the above embodiments and modifications, the vibration element 20 which is a kind of sensor element is given as an example of the quartz crystal vibrating piece. However, the present invention is not limited to this, for example, an acceleration sensing element that reacts to acceleration, pressure It may be a pressure sensing element that reacts, a weight sensing element that reacts to weight, or the like.
Further, the quartz crystal resonator element of the present invention is not limited to the sensor element such as the vibration element 20 described in the above embodiment and the modification, and may be a resonator used for an oscillator, for example.

  1, 1 ', 1 "... quartz wafer, 1a, 101a, 201a, 301a ... first surface, 1b ... second surface, 2, 3, 102, 202, 203, 302, 303 ... groove, 12, 13, 112, 212, 213, 312, 313 ... excitation electrodes, 113, 214, 215, 314 ... detection electrodes, 15, 16, 115, 116 ... external connection terminals, 20, 220, 320 ... as quartz crystal vibrating pieces Vibration element, 21, 121, 421, 521 ... base, 22, 23, 122, 123, 222, 223, 322, 323, 422-425, 522-524 ... vibration arm as vibration part, 40 ... IC chip, 40a ... active surface 45 ... electrode pad 60 ... package 61 ... first layer substrate 62 ... second layer substrate 63 ... third layer substrate 64 ... fourth layer substrate 65 ... IC connection terminal 66 ... Mau Electrode, 69, 97 ... bonding member, 70 ... lid, 95 ... bonding wire, 100 ... gyro sensor, 120, 420, 520 ... vibrating gyro element as crystal vibrating piece, 120a, 120b ... metal corrosion resistant film, 122a, 122b Etching mask, 131a, 131b ... Photoresist film, 132, 133 ... Development pattern, 136a, 136b, 137a ... Metalizing mask, 150, 250A, 250B ... Photomask, 152, 153, 252a, 252b, 253a, 253b ... Exposure pattern, 200 ... Gyro sensor, 240 ... Digital video camera as an electronic device, 241 ... Image receiving unit, 242 ... Operating unit, 243 ... Audio input unit, 1001 ... Display unit, 1002 ... Display unit, 1003 ... Display unit, 3000 Mobile phone as an electronic device, 3001 ... a plurality of operation buttons, 3002 ... scroll button, 4000 ... PDA, 4001 ... a plurality of operation buttons as an electronic device, 4002 ... power switch.

Claims (8)

The base,
The first surface, a second surface opposite to the first surface, and a pair of side surfaces connecting the first surface and the second surface are extended from the base portion. A method of manufacturing a quartz crystal resonator element comprising:
Forming a photoresist film on the first surface of the quartz substrate;
Using the same photomask, exposing the photoresist film to the outer shape of the base and the vibrating portion, and the shape of the opening of the groove in the formation region of the vibrating portion;
Developing the photoresist film after the exposing step;
Etching the outer shape and the groove by a wet etching method using the photoresist film patterned in the developing step as a mask, and
The method for manufacturing a quartz crystal resonator element, wherein the opening of the groove is formed to be shifted to one side of the side surface in a plan view. In the manufacturing method of the crystal vibrating piece according to claim 1,
In the groove, an imaginary line passing through the center of the opening in the first surface and extending along the extending direction passes through the center of gravity of the vibrating part before the groove is formed, and extends along the extending direction. A method of manufacturing a quartz crystal vibrating piece, characterized by being displaced with respect to an imaginary line. In the manufacturing method of the crystal vibrating piece according to claim 1 or 2,
A method of manufacturing a quartz crystal vibrating piece, comprising a step of etching from the second surface after the step of etching. In the manufacturing method of the crystal vibrating piece according to any one of claims 1 to 3,
The method of manufacturing a quartz crystal vibrating piece, wherein the etching step comprises simultaneously etching from both sides of the first surface and the second surface. The base,
Extending from the base and having a first surface, a second surface opposite to the first surface, and a pair of side surfaces connected to the first surface and the second surface A vibration part,
A groove is provided on the first surface of the vibration part,
In the groove, the opening is shifted to one side of the side surface in a plan view, and the depth of the groove is half of the thickness from the first surface to the second surface of the vibrating portion. Crystal vibrating piece characterized by deeper than. The quartz crystal resonator element according to claim 5,
The vibrating part has at least an electrode,
At least a part of the electrode is provided on the inner wall of the groove.   A gyro sensor comprising the quartz crystal resonator element according to claim 5.   An electronic device comprising the quartz crystal resonator element according to claim 5.

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