JP2011151567A - Tuning-fork type bending crystal vibration element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily form an electrode without short-circuiting an electrode for excitation provided on a side face of a vibration arm unit. <P>SOLUTION: A tuning-fork type bending crystal vibration element comprises: a base part; two pairs of vibration arm parts extending from the base part; and a projecting part that is positioned in the middle of the two vibration arm parts, extends in the same direction as that of the two pairs of vibration arm parts from the base part, and is formed to be shorter than the vibration arm parts. In the projecting part, a slit is provided along an extension direction, and the slit penetrates in a thickness direction and has a length from the tip of the projecting part to a boundary to the base part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tuning fork-type bending crystal resonator element used in electronic equipment.

Conventionally, a piezoelectric vibrator or a piezoelectric oscillator is mounted as an electronic component in an electronic device such as a computer, a mobile phone, or a small information device. This piezoelectric vibrator or piezoelectric oscillator is used as a reference signal source or a clock signal source. In addition, piezoelectric vibrators and piezoelectric oscillators are equipped with a piezoelectric vibration element made of quartz.
Hereinafter, a piezoelectric vibration element using quartz as a piezoelectric material will be described.
As shown in FIG. 3, a tuning-fork type bending crystal resonator element 400, which is one of piezoelectric resonator elements, includes a crystal resonator element 410, an excitation electrode, a connection electrode, and a frequency provided on the surface of the crystal resonator element 410. It is roughly constituted by an adjustment metal film and a conductive wiring pattern.

The quartz crystal vibrating piece 410 has a tuning fork shape, and is roughly constituted by a base portion 411 and a pair of vibrating arm portions 412 extending from the base portion 411. The vibrating arm portion 412 is provided with an excitation electrode 421 having the same polarity on opposing planes.
The base 411 is a substantially rectangular flat plate in plan view. The vibrating arm portion 412 includes a first vibrating arm portion 412a and a second vibrating arm portion 412b. The first vibrating arm portion 412a and the second vibrating arm portion 412b are extended in the same direction from one side of the base portion 411, and the length direction of the first vibrating arm portion 412a and the second vibrating arm portion 412b. Each is provided with a groove GL. The groove portion GL is formed on both main surfaces of the first vibrating arm portion 412a and the second vibrating arm portion 412b from the boundary portion with the base portion 411 toward the tip of the vibrating arm portion 412 in the longitudinal direction. Are provided in parallel with each other at a predetermined length. In such a quartz crystal vibrating piece 410, the base portion 411 and the vibrating arm portion 412 are integrally formed into a tuning fork shape, and is manufactured by a photolithography technique, a chemical etching technique, and a film forming technique.

  The electrode provided on the first vibrating arm portion 412 a is composed of an excitation electrode 421 and a frequency adjusting metal film 423. The excitation electrode 421 is provided on one main surface including the inner surface of the groove portion GL of the first vibrating arm portion 412a and the other main surface including the inner surface of the groove portion GL of the first vibrating arm portion 412a. The excitation electrode 421 has a different polarity between the inner side surface of the first vibrating arm portion 412a facing the second vibrating arm portion 412b and the outer side surface of the first vibrating arm portion 412a facing the side surface. It is provided to become. The frequency adjusting metal film 423 is provided on both main surfaces of the distal end portion of the first vibrating arm portion 412a.

  The electrode provided on the second vibrating arm portion 412 b is composed of an excitation electrode 421 and a frequency adjusting metal film 423. The excitation electrode 421 is provided on one main surface including the inner surface of the groove portion GL of the second vibrating arm portion 412b and the other main surface including the inner surface of the groove portion GL of the second vibrating arm portion 412b. . The excitation electrode 421 has a different polarity between the inner side surface of the second vibrating arm portion 412b facing the first vibrating arm portion 412a and the outer side surface of the second vibrating arm portion 412b facing the side surface. It is provided to become. The frequency adjusting metal film 423 is provided on both main surfaces of the distal end portion of the second vibrating arm portion 412a.

The base 411 is provided with two pairs of connection electrodes 422. One connection electrode 422 is provided from one corner end of the side opposite to the side where the vibrating arm portion 412 of the base 411 is formed and from one main surface of the base 411 to the other main surface. Yes. The other connection electrode 422 is provided from the other corner end of the side opposite to the side where the vibrating arm portion 412 of the base 411 is formed and from one main surface of the base 411 to the other main surface. It has been.
The base portion 411 and the vibrating arm portion 412 are provided with a conductive wiring pattern 424 for electrically connecting predetermined electrodes.

  One connection electrode 422 is electrically connected to an excitation electrode 421 provided on one main surface of the first vibrating arm portion 412a by a conductive wiring pattern 424 provided on one main surface of the base 411. In addition, it is electrically connected to the excitation electrode 421 provided on the outer side surface of the second vibrating arm portion 412b. In addition, the excitation electrode 421 provided on the outer side surface of the second vibrating arm portion 412b is electrically connected to the excitation electrode 421 provided on the inner side surface of the second vibrating arm portion 412b. Furthermore, the excitation electrode 421 provided on one main surface of the first vibrating arm portion 412 is connected to the first vibrating arm portion by the conductive wiring pattern 424 provided on the inner side surface of the first vibrating arm portion 412. It is electrically connected to an excitation electrode 421 provided on the other main surface of 412a.

  The other connection electrode 422 is electrically connected to the excitation electrode 421 provided on the other main surface of the second vibrating arm portion 412b by a conductive wiring pattern provided on the other main surface of the base portion 411. And, it is electrically connected to the excitation electrode 421 provided on the outer side surface of the first vibrating arm portion 412a. In addition, the excitation electrode 421 provided on the outer side surface of the first vibrating arm portion 412a is electrically connected to the excitation electrode 421 provided on the inner side surface of the first vibrating arm portion 412a. Further, the excitation electrode 421 provided on the other main surface of the second vibrating arm portion 412a is connected to the first vibrating arm portion by the conductive wiring pattern 424 provided on the inner side surface of the second vibrating arm portion 412b. It is electrically connected to an excitation electrode 421a provided on one main surface of 412a.

  The excitation electrode 421, the connection electrode 422, the frequency adjusting metal film 423a, and the conductive wiring pattern 424a are formed by sputtering, vapor deposition, or photolithography, and a laminated structure in which an Au layer is provided on a Cr layer. It has become.

  When the crystal vibrating piece 410 is vibrated, an alternating voltage is applied to the connection electrode 422. When an electrical state after application is instantaneously captured, the excitation electrodes 421 provided on both main surfaces of the first vibrating arm portion 412a have a positive potential, and the excitation electrodes 421 provided on both side surfaces are negative. An electric field is generated from positive to negative. At this time, the excitation electrodes 421 on both main surfaces of the second vibrating arm portion 412b have a negative potential, and the excitation electrodes 421 provided on both side surfaces have a positive potential, the excitation electrodes 421 of the first vibrating arm portion 412. The polarity is opposite to the polarity generated in, and an electric field is generated from plus to minus. The electric field generated by the alternating voltage causes an expansion / contraction phenomenon in the first vibrating arm portion 412a and the second vibrating arm portion 412b, and a bending vibration mode having a resonance frequency set in the vibrating arm portion 412 is set. The resonance frequency can be adjusted by increasing or decreasing the amount of metal constituting the frequency adjusting metal film 423 provided on the crystal vibrating piece 410 (see, for example, Patent Document 1 or 2).

Further, in such a tuning fork type bending quartz crystal vibrating element 400, electrodes are formed after the crystal vibrating piece 410 is formed in a tuning fork type.
For example, a corrosion resistant film (not shown) such as Cr or Cr + Au is formed on the front and back of a quartz wafer (not shown) by sputtering.

  Next, a photosensitive resist (positive type) is formed on both sides of the anticorrosion film, and after drying, exposure, development, drying (patterning) and anticorrosion other than the tuning fork shape so that the anticorrosion film on the front and back sides remains. Etch the film.

  Next, a photosensitive resist (positive type) is patterned on the front and back corrosion-resistant films in order to determine the shape of the electrodes. Here, a part of the photosensitive resist is provided so as to cover a connection portion between the vibrating arm portion and the base portion.

  Next, the exposed crystal portion is etched. At this time, the shape of the groove and the shape of the crystal vibrating piece 410 are formed simultaneously. Note that the photosensitive resist covering the connection portion between the vibrating arm portion 412 and the base portion 411 remains without being etched. Therefore, the base portion 411 and the vibrating arm portion 412 are formed with the photosensitive resist remaining. Therefore, this photosensitive resist is left in a state of straddling the two vibrating arm portions 412.

Next, the corrosion-resistant film exposed on the back surface is etched to obtain a crystal surface. Next, an electrode film is formed on the entire surface by a vapor deposition technique. At this time, an electrode film is not formed on the side surface of the base portion 411 to which the vibrating arm portion 412 is connected by the photosensitive resist that covers the connection portion between the vibrating arm portion 412 and the base portion 411, and the vibrating arm portion 412 An electrode film is formed only on the side surface.
Next, the photosensitive resist formed on the front and back and the electrode film formed thereon are peeled off. This can be easily removed by immersing it in a solution for dissolving the photosensitive resist. However, the anticorrosion film that remains in the lower portion remains. Next, the remaining corrosion-resistant film is etched.
In this way, electrodes are formed on the crystal vibrating piece 410 (see Patent Document 1).

JP 2007-329879 A JP 2004-248237 A

However, in such a tuning fork-type bending crystal resonator element 400, when an electrode is formed, if an evaporation technique is used, an electrode film may not be formed because a metal material hardly enters a narrow space such as a groove.
In order to solve this, when forming an electrode using a sputtering technique instead of the vapor deposition technique, the photosensitive resist covering the connection portion between the vibrating arm portion 412 and the base portion 411 cannot serve as a mask, An electrode film is formed on the side surface of the vibrating arm portion 412 and the side surface of the base portion 411, and the excitation electrode 421 is formed in a short state between the electrodes on the side surface where the vibrating arm portion 412a and the vibrating arm portion 412b face each other. End up.

  Therefore, an object of the present invention is to provide a tuning fork-type bending crystal resonator element that solves the above-described problems and prevents the excitation electrode provided on the side surface of the vibrating arm portion from being short-circuited.

  In order to solve the above-described problem, the present invention provides a tuning fork-type bending quartz crystal resonator element, which includes a base, a pair of vibrating arms extending from the base, and the vibrating arms between the base and the base. A protruding portion that is formed to be shorter than the vibrating arm portion while being extended, and a slit is provided in the protruding portion along the extending direction.

  In the present invention, a groove portion may be provided in each of the pair of vibrating arm portions along the extending direction.

  Further, according to the tuning fork-type bending quartz crystal resonator element of the present invention, since the slit is provided in the projecting portion along the extending direction, the slit can be provided even if the electrode film is provided by using the sputtering technique. This prevents the electrode film from being cut and the excitation electrode provided on the side surface of the vibrating arm portion from being short-circuited. Thereby, it becomes easy to form the excitation electrode provided on the side surface of the vibrating arm portion.

  Moreover, since the tuning fork-type bending quartz crystal resonator element according to the present invention is provided with the groove portion along the extending direction in each of the pair of vibrating arm portions, the electric field efficiency generated in each vibrating arm portion can be improved. .

It is a perspective view which shows an example of the tuning fork type bending crystal vibration element which concerns on embodiment of this invention. It is a top view which shows an example of the tuning fork type bending crystal vibration element which concerns on embodiment of this invention. It is a perspective view which shows an example of the conventional tuning fork type bending crystal vibration element.

  The best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate. Note that each component is exaggerated for easy understanding of the state.

  As shown in FIGS. 1 and 2, a tuning-fork type bending crystal resonator element 100 according to an embodiment of the present invention includes a crystal resonator element 110, an excitation electrode 121 and a connection electrode 122a provided on the crystal resonator element 110. , 122b, a frequency adjusting metal film 123, and a conductive wiring pattern 124.

The quartz crystal vibrating piece 110 has a tuning fork shape, and is a projection extending from the base 111 between the pair of vibrating arms 112 and the two vibrating arms 112 extending from the base 111. Part 113. The vibrating arm portion 112 is provided with excitation electrodes 121 having the same polarity on opposing planes.
The base 111 is a flat plate having a substantially rectangular shape in plan view. The vibrating arm portion 112 includes a first vibrating arm portion 112a and a second vibrating arm portion 112b. The first vibrating arm portion 112a and the second vibrating arm portion 112b extend in the same direction from one side of the base 111, and the length direction of the first vibrating arm portion 112a and the second vibrating arm portion 112b. Each is provided with a groove GL. The groove portion GL is formed on both main surfaces of the first vibrating arm portion 112a and the second vibrating arm portion 112b in the length direction of the vibrating arm portion 112 from the boundary portion with the base 111 toward the tip of the vibrating arm portion 112. Are provided in parallel with each other at a predetermined length. In such a quartz crystal vibrating piece 110, the base portion 111 and the vibrating arm portion 112 are integrally formed into a tuning fork shape, and is manufactured by a photolithography technique, a chemical etching technique, and a film forming technique.

  The electrode provided on the first vibrating arm portion 112 a is composed of an excitation electrode 121 and a frequency adjusting metal film 123. The excitation electrode 121 provided on the first vibrating arm portion 112a includes one main surface including the inner surface of the groove portion GL of the first vibrating arm portion 112a and the inner surface of the groove portion GL of the first vibrating arm portion 112a. It is provided on the other main surface. The excitation electrode 121 provided on the first vibrating arm portion 112a includes an inner side surface of the first vibrating arm portion 112a facing the second vibrating arm portion 112b and a first vibrating arm facing the side surface. It is provided on the outer side surface of the portion 112a and is provided so as to have a different polarity from the excitation electrode 121 provided on both main surfaces of the first vibrating arm portion 112a. The frequency adjusting metal film 123 provided on the first vibrating arm portion 112a is provided on both main surfaces of the distal end portion of the first vibrating arm portion 112a. The frequency adjusting metal film 123 may be provided on at least one main surface.

  The electrode provided on the second vibrating arm portion 112 b is composed of an excitation electrode 121 and a frequency adjusting metal film 123. The excitation electrode 121 provided on the second vibrating arm portion 112b includes one main surface including the inner surface of the groove portion GL of the second vibrating arm portion 112b and the inner surface of the groove portion GL of the second vibrating arm portion 112b. It is provided on the other main surface. The excitation electrode 121 provided on the second vibrating arm portion 112b includes an inner side surface of the second vibrating arm portion 112b facing the first vibrating arm portion 112a and a second vibrating arm facing the side surface. It is provided on the outer side surface of the portion 112b and is provided so as to have a different polarity from the excitation electrode 121 provided on both main surfaces of the second vibrating arm portion 112b. The frequency adjusting metal film 123 provided on the second vibrating arm portion 112b is provided on both main surfaces of the distal end portion of the second vibrating arm portion 112a. The frequency adjusting metal film 123 may be provided on at least one main surface.

The base 111 is provided with connection electrodes 122a and 122b. The connection electrode 122 a is provided from one corner end of the side opposite to the side where the vibrating arm portion 112 of the base 111 is formed and from one main surface of the base 111 to the other main surface. The connection electrode 122b is provided from the other corner end of the side opposite to the side on which the vibrating arm portion 112 of the base 111 is formed and from one main surface of the base 111 to the other main surface. Yes.
Further, the base portion 111 and the vibrating arm portion 112 are provided with a conductive wiring pattern 124 for electrically connecting predetermined electrodes.

  The connection electrode 122a is electrically connected to the excitation electrode 121 provided on one main surface of the first vibrating arm portion 112a by the conductive wiring pattern 124 provided on one main surface of the base 111, And it is electrically connected to the excitation electrode 121 provided on the outer side surface of the second vibrating arm portion 112b. Further, the excitation electrode 121 provided on the outer side surface of the second vibrating arm portion 112b is electrically connected to the excitation electrode 121 provided on the inner side surface of the second vibrating arm portion 112b. Further, the excitation electrode 121 provided on one main surface of the first vibrating arm portion 112a is formed on the other main surface of the first vibrating arm portion 112a by a conductive wiring pattern provided on the side surface of the base 111. It is electrically connected to the provided excitation electrode 121.

  The connection electrode 122b is electrically connected to the excitation electrode provided on the other main surface of the second vibrating arm portion 112b by a conductive wiring pattern provided on the other main surface of the base 111, and It is electrically connected to an excitation electrode provided on the outer side surface of the first vibrating arm portion 112a. In addition, the excitation electrode provided on the outer side surface of the first vibrating arm portion 112a is electrically connected to the excitation electrode 121 provided on the inner side surface of the first vibrating arm portion 112a. Furthermore, the excitation electrode 121 provided on the other main surface of the second vibrating arm portion 112a is connected to one main surface of the second vibrating arm portion 112b by a conductive wiring pattern provided on the inner side surface of the base portion 111. Is electrically connected to the excitation electrode 121 provided on the substrate.

  The excitation electrode 121, the connection electrodes 122a and 122b, and the conductive wiring pattern 124 are formed by a photolithography technique and have a laminated structure in which a Pd or Au layer is provided on a Ti layer.

  When this tuning-fork type crystal vibrating piece 110 is vibrated, an alternating voltage is applied to the connection electrodes 122a and 122b. When an electrical state after application is instantaneously captured, the excitation electrodes 121 provided on both main surfaces of the first vibrating arm portion 112a have a positive potential, and the excitation electrodes 121 provided on both side surfaces are negative. An electric field is generated from positive to negative. At this time, the excitation electrodes 121 on both main surfaces of the second vibrating arm portion 112b have a negative potential, and the excitation electrodes 121 provided on both side surfaces have a positive potential, the exciting electrodes 121 of the first vibrating arm portion 112a. The polarity is opposite to the polarity generated in, and an electric field is generated from plus to minus. The electric field generated by the alternating voltage causes an expansion / contraction phenomenon in the first vibrating arm portion 112a and the second vibrating arm portion 112b, and a bending vibration mode having a resonance frequency set in the vibrating arm portion 112 is set. The resonance frequency can be adjusted by increasing or decreasing the amount of metal constituting the frequency adjusting metal film 123 provided on the tuning-fork type crystal vibrating piece 110.

The protruding portion 113 is intermediate between the pair of vibrating arm portions 112, and extends from the base portion 111 along the vibrating arm portion 112.
Further, the protrusion 113 is provided shorter than the vibrating arm 112 and is provided so that the width is larger, smaller, or the same as that of the vibrating arm 112.
A slit 113b is provided on the distal end side of the protruding portion 113 along the extending direction. The slit 113b penetrates the protrusion 113 in the thickness direction. Further, the slit 113b may have any length as long as it is formed between the tip side and the boundary of the base 111.

The slit 113b provided in the protrusion 113 forms an excitation electrode on the side surface of the vibrating arm portion 112 including the first vibrating arm portion 112a and the second vibrating arm portion 112b by a sputtering technique and a photolithography technique. In doing so, it plays a role of cutting the short-circuited state between the excitation electrode 121 on the side surface of the first vibrating arm portion 112a and the excitation electrode 121 on the side surface of the second vibrating arm portion 112b.
The protrusion 113 only needs to have a length that allows the slit 113b to be formed. For example, the protrusion 113 has a length smaller than the distance between the first vibrating arm 112a and the second vibrating arm 112b. If it is formed by. In other words, the protrusion 113 may be provided so as to be shorter than the distance between the pair of vibrating arms 112.

  Specifically, this slit 113b provided in the protrusion 113 is used as follows. In order to explain the role of the slit 113b, a method of manufacturing the tuning-fork type bending crystal resonator element 100 according to the embodiment of the present invention will be described.

For example, in the tuning fork-type bending crystal resonator element 100 according to the embodiment of the present invention, the electrodes are formed after the crystal resonator element 110 is formed on the tuning fork.
For example, a corrosion resistant film (not shown) such as Cr or Cr + Au is formed on the front and back of a quartz wafer (not shown) by sputtering.

  Next, a photosensitive resist (positive type) is formed on both sides of the anticorrosion film, and after drying, exposure, development, drying (patterning) and anticorrosion other than the tuning fork shape so that the anticorrosion film on the front and back sides remains. Etch the film.

  Next, a photosensitive resist (positive type) is patterned on the front and back corrosion-resistant films in order to determine the shape of the electrodes. Here, a part of the photosensitive resist is provided so as to cover a connection portion between the protruding portion 113 including the inside of the slit 113 b, the vibrating arm portion 112, and the base portion 111.

  Next, the exposed crystal portion is etched. At this time, the shape of the slit 113b, the shape of the groove GL, and the shape of the quartz crystal vibrating piece 110 are formed simultaneously. Note that the photosensitive resist covering the connection portion of the protrusion 113, the vibrating arm 112, and the base 111 remains without being etched. Therefore, the base 111, the vibrating arm 112, and the protrusion 113 are formed with the photosensitive resist remaining. Therefore, this photosensitive resist remains at least on the protrusion 113 in a state of straddling the slit 113.

Next, the corrosion-resistant film exposed on the front and back surfaces is etched to obtain a crystal surface. Next, an electrode film is formed on the entire surface by sputtering. At this time, an electrode film is formed on the side surface of the protrusion 113 across the slit 113b by the photosensitive resist that covers the protrusion 113 across the slit 113b.
Next, the photosensitive resist formed on the front and back and the electrode film formed thereon are peeled off. This can be easily removed by immersing it in a solution for dissolving the photosensitive resist. However, the anticorrosion film that remains in the lower portion remains. Since the photosensitive resist straddling the slit 113b is also removed, the electrode on the side surface of the first vibrating arm portion 112a and the electrode on the side surface of the second vibrating arm portion 112b are cut. Next, the remaining corrosion-resistant film is etched.
In this way, since the electrodes are formed on the crystal vibrating piece 110, the electrodes on the side surface of the first vibrating arm portion 112a and the electrodes on the side surface of the second vibrating arm portion 112b are short-circuited even when sputtering is used. The cut state can be changed to the cut state.

In addition, although embodiment of this invention was described, this invention can be changed suitably.
For example, the metal film for frequency adjustment may be separately thickened using a metal material such as Ag (silver) or Au (gold).
Further, the tuning fork-type bending crystal resonator element of the present invention can be used in a piezoelectric vibrator by being enclosed in a predetermined package. In this state, the piezoelectric oscillator is configured to be connected to an integrated circuit element including an oscillation circuit. You may use for.

DESCRIPTION OF SYMBOLS 100 Tuning fork type bending crystal vibrating element 110a Quartz vibrating piece 111 Base 112 Vibrating arm part 112a First vibrating arm part 112b Second vibrating arm part 121 Excitation electrode 122a, 122b Connection electrode 123 Frequency adjusting metal film 124 Conductive wiring Pattern 113 Projection 113b Slit GL Groove

Claims (2)

The base,
Two pairs of vibrating arms extending from the base,
A projection formed between the vibrating arms and extending from the base while being shorter than the vibrating arms;
A tuning-fork-type bent quartz crystal vibrating element, wherein the protrusion is provided with a slit along the extending direction.   The tuning fork-type bending crystal resonator element according to claim 1, wherein a groove portion is provided in each of the pair of vibrating arm portions along the extending direction.

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