JP2006013900A - Piezoelectric vibrating piece, piezoelectric vibrator, manufacturing method thereof, and piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively form a connection electrode that does not hinder the conductivity even when connecting a crystal vibrating piece and a cage using a silicone-based conductive adhesive without increasing the number of steps. A piezoelectric vibrator is provided.
In a crystal resonator 1 as a piezoelectric resonator, a connection electrode 34 of a crystal resonator element 2 is connected to a cage 30 by a silicone-based conductive adhesive 35. On the surface of the crystal vibrating piece 2, the connection electrode 34 described above, the excitation electrode 33 connected to the connection electrode 34, and the frequency adjusting electrode 38 provided near the tips of the arm portions 22 and 23 are formed. The connection electrode 34 has a single layer structure of a chromium layer 38a that is a first metal layer provided on the surface of the quartz crystal vibrating piece 2, and the frequency adjusting electrode 38 is provided on the surfaces of the chromium layer 38a and the chromium layer 38a. This is a three-layer structure of a gold layer 38b, which is the second metal layer formed, and a weight metal layer 38c formed of gold or silver provided on the gold layer 38b.
[Selection] Figure 2

Description

  The present invention relates to a piezoelectric vibrator having a piezoelectric vibrating piece using a piezoelectric base material such as quartz, the piezoelectric vibrating piece, a method for manufacturing the piezoelectric vibrator, and a piezoelectric oscillator including the piezoelectric vibrating piece.

  As shown in the front sectional view of FIG. 9, the conventional piezoelectric vibrator is configured by connecting a crystal vibrating piece 200 that is a piezoelectric base material to a holder 201 that supports the crystal vibrating piece 200. This connection is made with a silicone-based conductive adhesive 205, and a chromium diffusion layer 202, which is a surface layer of the connection electrode 206 formed at the end of the crystal vibrating piece 200, and a support electrode 201a formed on the cage 201, Are electrically connected via a silicone-based conductive adhesive 205. The connection electrode 206 includes a base chrome layer 204 provided on the surface of the quartz crystal vibrating piece 200, a gold electrode layer 203 provided on the surface of the base chrome layer 204, and a base chrome layer 204 on the surface of the gold electrode layer 203. The chrome diffusion layer 202 is partially diffused (for example, FIG. 2 of Patent Document 1).

The silicone-based conductive adhesive 205 is a paste-like adhesive in which conductive particles (also referred to as fillers) made of, for example, silver are mixed with a silicone resin as a base material, and is heated and cured after application.
The silicone resin in the silicone-based conductive adhesive has a faster curing reaction when silver is in the vicinity than when gold is in the vicinity. For this reason, when gold is used as an electrode material such as the connection electrode 206, the silver periphery contained in the conductive adhesive itself is hardened earlier than the gold electrode surface portion. On the other hand, when the silicone-based conductive adhesive undergoes a curing reaction, the adhesive itself contracts. Therefore, when the silicone-based conductive adhesive is cured, silver particles around the surface of the gold electrode, which is a slow curing reaction portion, move away from the surface of the gold electrode due to curing shrinkage.

  As a result, after curing of the silicone-based conductive adhesive, a silicone resin layer without conductive particles may be generated at the interface between the silicone-based conductive adhesive and the gold electrode surface as a result. It is assumed that the silicone resin is cured together with the conductive particles. In any case, when the surface of the connection electrode is a slower material than the conductive particles such as silver contained in the silicone-based conductive adhesive itself, the interface with the connection electrode when the surface of the connection of the silicone resin such as gold is slow. In some cases, a silicone resin layer is formed.

  The chromium diffusion layer 202 prevents the conductivity of the gold electrode layer 203 and the support electrode 201a of the cage 201 from being obstructed by the silicone-based conductive adhesive 205 caused by the silicone resin layer generated as described above. It is provided to do.

JP 2000-151345 A

  However, the piezoelectric vibrator described in the background art described above requires a diffusion process such as a heat treatment for forming the chromium diffusion layer 202, and thus has the problem that the number of processes increases and productivity is hindered. Was.

  The present invention has been made in view of the above problems, and the object of the present invention is to inhibit electrical conductivity even when the quartz crystal vibrating piece and the cage are connected using a silicone-based conductive adhesive. An object of the present invention is to provide an inexpensive piezoelectric vibrator by forming a connection electrode that does not occur without increasing the number of steps.

In order to solve such a problem, the piezoelectric vibrating piece of the present invention is a piezoelectric vibrating piece connected to a cage by a silicone-based conductive adhesive, and has a tuning fork-shaped piezoelectric substrate having a pair of arm portions as vibrating portions. Material, an excitation electrode formed by a first metal layer made of a chromium-based or nickel-based metal provided over the arm portion on the surface of the piezoelectric base material, and the base side surface of the piezoelectric base material on the base side surface A connection electrode formed by the first metal layer provided in connection with the excitation electrode, and the first metal layer exposed at least partially on the surface of the connection electrode is bonded to the silicone-based conductive adhesive In this state, the base is bonded and fixed to the cage.
According to the piezoelectric vibrating piece of the present invention, the chromium-based or nickel-based first metal layer provided on the surface of the piezoelectric base material is used as a connection electrode, so that the number of processes is not increased and the number of processes is increased. A connection electrode with the metal layer exposed on the surface can be obtained. Accordingly, it is possible to provide a piezoelectric vibrating piece that does not hinder energization at low cost even when connection using a silicone-based conductive adhesive is performed.

The connection electrode is preferably formed only from the first metal layer.
If it does in this way, since it forms only from the 1st metal layer, a connection electrode can be formed efficiently.

It is desirable that an insulating surface protective layer is formed so as to cover at least the excitation electrode.
If it does in this way, it will become possible to prevent the short circuit between electrodes by the conductive foreign material adhering to the surface of an excitation electrode.

The connection electrode preferably includes the first metal layer and the second metal layer provided on a part of the first metal layer.
In this way, since it has the first metal layer and the second metal layer on the surface of the connection electrode, in the case of connection using a silicone-based conductive adhesive, energization can be secured in the first metal layer, In the case of other connection methods, for example, solder connection, it is possible to increase the solder wettability at the portion of the second metal layer and ensure energization. That is, it is possible to provide a piezoelectric vibrating piece that can be connected without being interrupted even if the connection method changes.

Further, it is preferable that the connection electrode is formed of the second metal layer in the vicinity of the outer edge of the connection electrode and the first metal in the center of the connection electrode.
If it does in this way, since connection is performed by both metal layers in the case of connection, reliable connection, such as connection strength and electrical conductivity, can be performed.

A frequency having at least the first metal layer and a second metal layer provided on the first metal layer at a position on the tip side of the excitation electrode in the pair of arms of the piezoelectric substrate. It is desirable that an adjustment electrode is formed.
In this way, since the first metal layer of chromium or nickel is a metal layer having good adhesion to both the piezoelectric substrate and the second metal layer, the adhesion of the frequency adjusting electrode to the piezoelectric substrate is improved. It can be secured. That is, in addition to the effects described above, by further ensuring the adhesion of the frequency adjustment electrode, it is possible to prevent the resonance frequency of the piezoelectric vibrating piece from changing due to peeling of the frequency adjustment electrode, and to stabilize the resonance frequency for a long period of time. It becomes.

Preferably, the second metal layer is made of gold, and the frequency adjusting electrode further includes a frequency adjusting weight metal layer formed on the surface of the second metal layer.
In this case, since the second metal layer is formed of gold that does not cause a chemical change (particularly oxidation phenomenon), a weight adjusting metal layer for frequency adjustment is provided on the surface of the second metal layer. However, the deterioration of the adhesion between the second metal layer and the metal layer for frequency adjustment due to oxidation or the like can be prevented. In other words, by ensuring the adhesion of the frequency adjusting weight metal layer, it is possible to prevent a change in the resonance frequency of the piezoelectric vibrating piece due to peeling of the frequency adjusting weight metal layer and to stabilize the resonance frequency for a long period of time. It becomes possible.

The piezoelectric vibrator of the present invention includes a retainer and the above-described piezoelectric vibrating piece connected to the retainer, and the first metal exposed at least partially on a surface of the connection electrode of the piezoelectric vibrating piece. The layer is bonded and fixed to the retainer at the base in a state where the layer is bonded to the silicone-based conductive adhesive.
According to the piezoelectric vibrator of the present invention, the chromium-based or nickel-based first metal layer provided on the surface of the piezoelectric base material is used as the connection electrode, so that the number of processes is not increased and the number of processes is increased. A connection electrode with the metal layer exposed on the surface can be obtained. Accordingly, it is possible to provide a piezoelectric vibrator that does not hinder energization at low cost even when connection using a silicone-based conductive adhesive is performed.

The method of manufacturing a piezoelectric vibrating piece according to the present invention includes, on the surface of a piezoelectric substrate, at least an excitation electrode for oscillating the piezoelectric substrate, a connection electrode connected to the excitation electrode and connected to the cage, A piezoelectric vibrating piece having a frequency adjusting electrode for adjusting an oscillation frequency of the piezoelectric substrate, wherein a first metal layer of chromium or nickel and a first metal layer of chromium or nickel are formed on the surface of the piezoelectric substrate. A step of forming an electrode film composed of a gold second metal layer covering the surface; and a first mask is provided on the surface of the electrode film, and a portion of the electrode film not covered by the first mask is removed. And providing a second mask for covering the frequency adjusting electrodes, and dividing at least the second metal layers of the excitation electrodes and the connection electrodes that are not covered by the second mask. Remove and expose the first metal layer A step of providing a third mask for covering a region excluding the frequency adjustment electrode, and forming a weight metal layer for frequency adjustment over the frequency adjustment electrode not covered with the third mask; It is characterized by having.
According to the method for manufacturing a piezoelectric vibrating piece of the present invention, the connection electrode is formed by the first metal layer on the surface of the piezoelectric substrate, and the frequency adjusting electrode is formed by the second metal layer provided to overlap the first metal layer. In addition, it is possible to form a weight electrode for frequency adjustment over the frequency adjustment electrode. Therefore, since the conductivity of the connection by the connection electrode is ensured and the second metal layer is formed of gold that does not cause chemical change (particularly oxidation phenomenon), the weight for adjusting the frequency is formed on the surface of the second metal layer. Even when the metal layers are provided in an overlapping manner, it is possible to prevent deterioration in adhesion between the second metal layer and the frequency adjusting metal layer due to oxidation or the like. In other words, by increasing the reliability of the conductive properties of the connection electrodes and ensuring the adhesion of the weight adjustment metal layer, the frequency change of the piezoelectric vibrator due to peeling of the frequency adjustment weight metal layer is prevented. Thus, it is possible to provide a piezoelectric vibrating piece that can stabilize the frequency for a long period of time and can improve long-term reliability.

The method of manufacturing a piezoelectric vibrating piece according to the present invention includes, on the surface of a piezoelectric substrate, at least an excitation electrode for oscillating the piezoelectric substrate, a connection electrode connected to the excitation electrode and connected to the cage, A method of manufacturing a piezoelectric vibrator having a frequency adjusting electrode for adjusting an oscillation frequency of a piezoelectric substrate, the step of forming a first metal layer of chromium or nickel on the surface of the piezoelectric substrate; A step of providing a first mask on the surface of the first metal layer, removing the portion of the first metal layer not covered by the first mask, and dividing the first metal layer; and the frequency adjusting electrode. A step of providing a third mask covering a region excluding the portion and forming a weight metal layer for frequency adjustment over the first metal layer not covered by the third mask. And
According to the method for manufacturing a piezoelectric vibrating piece of the present invention, the connection electrode is formed by the first metal layer on the surface of the piezoelectric substrate, and the frequency adjustment weight is superimposed on the first metal layer of the frequency adjustment electrode portion. A metal layer can be formed. Therefore, it is possible to easily form the connection electrode and the frequency adjusting electrode that ensure the conductivity of the connection.

According to the method for manufacturing a piezoelectric vibrator of the present invention, a cage that holds the piezoelectric substrate in a connected state, an excitation electrode for oscillating at least the piezoelectric substrate on the surface of the piezoelectric substrate, A method of manufacturing a piezoelectric vibrator having a connection electrode connected to the excitation electrode and connected to the cage, and a frequency adjusting electrode for adjusting an oscillation frequency of the piezoelectric substrate, The piezoelectric vibrating reed manufactured by the method for manufacturing a piezoelectric vibrating reed according to claim 10 is bonded and fixed to the cage at a base using a silicone-based conductive adhesive, and is exposed on the surface of the connection electrode. The method includes a step of electrically connecting the connection electrode and the cage in a state where the first metal layer and the silicone-based conductive adhesive are bonded.
According to the method for manufacturing a piezoelectric vibrating piece of the present invention, the connection electrode is formed by the first metal layer on the surface of the piezoelectric substrate, and the frequency adjusting electrode is formed by the second metal layer provided to overlap the first metal layer. In addition, it is possible to form a weight electrode for frequency adjustment over the frequency adjustment electrode. Therefore, since the conductivity of the connection by the connection electrode is ensured and the second metal layer is formed of gold that does not cause chemical change (particularly oxidation phenomenon), the weight for adjusting the frequency is formed on the surface of the second metal layer. Even when the metal layers are provided in an overlapping manner, it is possible to prevent deterioration in adhesion between the second metal layer and the frequency adjusting metal layer due to oxidation or the like. In other words, by increasing the reliability of the conductive properties of the connection electrodes and ensuring the adhesion of the weight adjustment metal layer, the frequency change of the piezoelectric vibrator due to peeling of the frequency adjustment weight metal layer is prevented. Thus, it is possible to provide a piezoelectric vibrator capable of stabilizing the frequency for a long period of time and improving the long-term reliability.

  Further, the cage, the piezoelectric vibrating piece according to any one of claims 1 to 7 connected to the cage by a silicone-based conductive adhesive, and a function of causing at least the piezoelectric vibrating piece to oscillate. The first metal layer exposed at least partially on the surface of the connection electrode of the piezoelectric vibrating piece is bonded to the silicone-based conductive adhesive and held at the base thereof. It is also possible to provide a piezoelectric oscillator characterized in that it is adhesively fixed to a container.

The best mode of the piezoelectric vibrator according to the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments described later.
(First embodiment)

  As a first embodiment of the piezoelectric vibrator according to the present invention, a tuning-fork-shaped crystal piece (hereinafter referred to as “crystal vibrator piece”) is used as an example of a piezoelectric vibrator in a bending vibration mode or a longitudinal vibration mode. A surface-mount type crystal resonator will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing the crystal resonator according to the first embodiment. FIG. 2 is a schematic cross-sectional view taken along the line P-P in FIG.

=== Whole structure of crystal unit ===
As shown in FIG. 1, the crystal resonator 1 according to this embodiment includes a crystal resonator element 2 that is an example of a thin plate-like piezoelectric base material in which two (a pair) arm portions 22 and 23 extend from a base portion 21. The holder 30 is connected to and holds the crystal vibrating piece 2. The cage 30 is made of ceramic, and accommodates the crystal vibrating piece 2 in the recess. The bottom surface of the recess has a step structure, and the one step higher part is a holding part 31 of the crystal vibrating piece, and the connection between the metal wiring 31a (shown in FIG. 2) formed with the holding part 31 of the crystal vibrating piece and the crystal vibrating piece 2 The electrode 34 is connected by a silicone-based conductive adhesive 35. The lower portion 32 is for holding the arm portions 22 and 23 that are the vibrating portions of the quartz crystal vibrating piece 2 in a hollow state.

On the surface of the crystal vibrating piece 2, the connection electrode 34 described above, the excitation electrode 33 connected to the connection electrode 34, and the frequency adjusting electrode 38 provided near the tips of the arm portions 22 and 23 are formed. The connection electrode 34 and the excitation electrode 33 are formed of a chromium layer 38a that is a first metal layer. As shown in FIG. 2, the frequency adjusting electrode 38 includes a chromium layer 38a provided on the surface of the crystal vibrating piece 2, a gold layer 38b that is a second metal layer provided on the surface of the chromium layer 38a, It has a three-layer structure of a weight metal layer 38c formed of gold or silver provided to overlap the layer 38b. The details of the electrode configuration will be described later.
Further, a surface protective layer 39 indicated by a two-dot chain line in FIG. 2 may be formed on the surface of the excitation electrode 33 in a region excluding the connection electrode 34 and the frequency adjusting electrode 38.

  A metal lid 36 is in close contact with the upper surface 37 of the holder 30 in which the crystal vibrating piece 2 is housed, and the inside of the recess of the holder 30 is kept airtight.

=== Electrode Configuration of Crystal Vibrating Piece ===
The electrode configuration of the crystal vibrating piece will be described with reference to FIGS. 3A and 3B are perspective views of the quartz crystal resonator element, where FIG. 3A is a perspective view when viewed obliquely from above, and FIG. 3B is a perspective view when viewed from obliquely below. 4A and 4B are side cross-sectional views schematically showing each part of the quartz crystal vibrating piece, in which FIG. 4A is a cross-sectional view of an arm portion (A-A cross section in FIG. 3A), and FIG. 4B is a base portion. FIG. 3C is a cross-sectional view (cross-section BB in FIG. 3A), and FIG.

  As shown in FIGS. 3 (a) and 3 (b), the two parts formed with a predetermined gap 27 are formed at the central portions of the upper surface portion 25 and the lower surface portion 26 of the arm portions 22, 23 of the crystal vibrating piece 2. Excitation electrodes 33 are formed by the electrode patterns 40, respectively. 3A and 3B, in order to distinguish the two electrode patterns 40, one electrode pattern 40 is given a right-down oblique line, and the other electrode pattern 40 is given a right-up oblique line. In addition, each is illustrated.

  Here, since the excitation electrode 33 is formed in the center part in the upper surface part 25 and the lower surface part 26 of the arm parts 22 and 23 of the crystal vibrating piece 2, the excitation electrode 33 on the upper surface part 25 side of the crystal vibrating piece 2. The excitation electrode 33 on the lower surface portion 26 side includes edge portions 251, 252, 253, 254 of the upper surface portion 25, edge portions 261, 262, 263, 264 of the lower surface portion 26, and side surface portions 271, 272. They are electrically connected by a conductive electrode 46 formed by the formed electrode pattern 40.

  Therefore, as shown in FIG. 1, if an AC voltage is applied to the excitation electrode 33 via a connection electrode (also referred to as a mount portion) 34 formed on the base portion 21 in the electrode pattern 40, the arm portions 22, 23. Vibrates at a predetermined frequency. In this case, the conduction electrode 46 also has a function of exciting the crystal vibrating piece 2. Note that a frequency adjusting electrode 38 for adjusting the frequency by laser trimming or the like is formed on the distal end side of the arm portions 22 and 23.

  As shown in FIG. 4A, the electrode pattern 40 of the arm portions 22 and 23 of the crystal vibrating piece 2 has a first metal layer 41 (hereinafter referred to as “chrome layer”) made of chromium on the surfaces of the arm portions 22 and 23. .)). The chromium layer 41 is divided by a predetermined gap 27 to form an electrode pattern 40 (in this figure, an excitation electrode 33 is shown as an example of the electrode pattern 40). It should be noted that the surface of the chromium layer 41 constituting the excitation electrode 33 and the portion where the upper surface portion 25 and the lower surface portion 26 of the quartz are exposed by the gap 27 dividing the electrode are exposed to silicon oxidation indicated by a one-dot chain line in FIG. A surface protective layer 39 such as a film may be provided.

  As shown in FIG. 4B, the connection electrode 34 provided on the base 21 is formed on the surface of the base 21 of the quartz crystal vibrating piece 2 by a single layer structure of the same chromium layer 41 as the excitation electrode 33 described above. . The connection electrode 34 is divided into two by a gap 44, and each is connected to the excitation electrode 33.

  The frequency adjusting electrode 38 provided in the vicinity of the tips of the arm portions 22 and 23 of the crystal vibrating piece 2 is formed in a three-layer structure as shown in FIG. Explaining the three-layer structure, the same chromium layer 41 as the above-described excitation electrode 33 and connection electrode 34 is formed on the surfaces of the arm portions 22 and 23 as a first metal layer. On the surface of the chromium layer 41, a gold layer 47 is formed as a second metal layer. Further, a weight metal layer 49 as a third metal layer made of gold or silver is formed on the surface of the gold layer 47. The weight metal layer 49 may not be provided on both the front and back surfaces as long as the mass capable of frequency adjustment can be formed, and a configuration provided on either one of the front and back surfaces can also be used.

  The chrome layer 41 is formed in order to improve the adhesion between the gold layer 47 and the surface of the quartz crystal vibrating piece 2. Further, the gold layer 47 has a deterioration in adhesion between the chromium layer 41 and the weight metal layer 49 due to a surface alteration layer such as oxidation of the surface that occurs when the chromium layer 41 is exposed to the atmosphere before the weight metal layer 49 is formed. Form to prevent. Therefore, gold (Au) that does not cause chemical changes such as oxidation is used.

  Therefore, the frequency adjusting electrode 38 can prevent the deterioration of the surface of the chromium layer 41 by forming the chromium layer 41 and the weight metal layer 49 in the same vacuum chamber. It is good also as 2 layer structure which forms 49 directly.

According to the first embodiment described above, the connection electrode 34 provided on the surface of the quartz crystal vibrating piece 2 is used as the first metal layer of the chromium layer 41, so that the chromium layer can be formed on the surface without using a diffusion process or the like. The exposed connection electrode 34 can be obtained. Therefore, it is possible to provide the crystal resonator 1 that is not obstructed by energization even if connection using the silicone-based conductive adhesive 35 is performed at low cost.
It is also possible to use the first metal layer of the chromium layer 41 described above as a base electrode, and provide a gold layer 47 and a weight metal layer 49 constituting the frequency adjusting electrode 38 on the surface thereof. That is, it is possible to form the frequency adjusting electrode 38 with improved adhesion to the crystal vibrating piece 2.

=== Modification Example of Connection Electrode ===
Here, a modified example of the connection electrode will be described. FIGS. 5A to 5D are different modifications of the quartz crystal resonator element, and are a DD cross-sectional view and a plan view showing a connection electrode portion, respectively.

  According to FIG. 5A, the connection electrode 34 provided on the surface of the quartz crystal vibrating piece 2 has a two-layer structure of a chromium layer 50 and a gold layer 51. The chromium layer 50 is provided in the entire region of the connection electrode 34, and the gold layer 51 is formed to overlap the chromium layer 50 in a band shape at both ends in the width direction of the crystal vibrating piece 2 of the connection electrode 34.

  According to FIG. 5B, the connection electrode 34 has a two-layer structure as described above. The chromium layer 50 is provided in the entire region of the connection electrode 34. The gold layer 51 provided so as to overlap the chromium layer 50 has a plurality of rectangular window opening portions, and the chromium layer 50 is exposed at the window opening portions.

  According to FIG. 5C, the connection electrode 34 has a two-layer structure as described above. The chromium layer 50 is provided in the entire region of the connection electrode 34. The gold layer 51 provided so as to overlap the chromium layer 50 has a circular window opening, and the chromium layer 50 is exposed at the window opening.

  According to FIG. 5D, the connection electrode 34 has a two-layer structure as described above. The chromium layer 50 is provided in the entire region of the connection electrode 34. The gold layer 51 provided so as to overlap the chromium layer 50 is formed in a band shape at the center portion in the width direction of the crystal vibrating piece 2 of the connection electrode 34.

According to each modification of the connection electrode described above, when the connection electrode 34 has a portion where the chromium is exposed and a portion where the gold is exposed, the connection is performed using the silicone-based conductive adhesive 35. In FIG. 5, the chromium layer 50 that is partially exposed can be connected without being interrupted. In addition, since the gold layer 51 is also exposed, it is possible to generate a good solder flow even when connecting by soldering. Therefore, the connection electrode 34 which can respond to both the connection using a silicone type conductive adhesive and the connection using soldering can be formed by using this modification.
(Second embodiment)

  A method for manufacturing a piezoelectric vibrator according to the present invention will be described with reference to the drawings, taking a method for manufacturing a tuning fork type crystal vibrator as an example. FIG. 6 is a diagram showing a process flow for forming an electrode of a crystal vibrating piece in a manufacturing process of a tuning fork type crystal resonator, in which a BB cross section shows a base portion 21 and a CC cross section shows an arm portion 22. , 23 shows the portion of the frequency adjusting electrode 38 formed at the tip of the tip.

  In the manufacture of the crystal vibrating piece 2, the outer shape of the crystal vibrating piece is formed prior to the formation of the electrode, but in this description, the process of forming the electrode is omitted. In the manufacturing process of the quartz crystal vibrating piece 2, electrodes are simultaneously formed on both the upper and lower surfaces of the quartz substrate, which is a piezoelectric base material, and the electrodes are similarly formed on the side surfaces.

  First, as shown in FIG. 6A, an electrode film is formed on the entire surface of the quartz crystal vibrating piece 2 formed with the outer shape (in FIG. 6, the tip portions of the base portion 21 and the arm portions 22 and 23 are shown). A chromium layer 41 that is a first metal layer to be formed, and a gold layer 47 that is a second metal layer are formed on the surface of the chromium layer 41. The chromium layer 41 and the gold layer 47 are formed by vacuum sputtering or vacuum deposition.

  Next, the chromium layer 41 and the gold layer 47 are divided to form respective electrode shapes. After a photoresist 60 as a first mask is formed on the surface of the gold layer, baking is performed on each electrode shape (also referred to as exposure). Subsequently, development is performed to leave the photoresist 60 in the shape of each electrode as shown in FIG. The portion of the photoresist 60 where the electrodes are divided is a window opening 61 where the photoresist 60 does not exist.

  Next, the gold layer 47 and the chromium layer 41 are etched using the photoresist 60 as a mask. By this etching process, the gold layer 47 corresponding to the window opening 61 of the photoresist 60 and the chromium layer 41 are removed to form a gap 62 (also referred to as an electrode dividing line), as shown in FIG. The chromium layer 41 and the gold layer 47 are left in a shape corresponding to each electrode. Thereafter, the photoresist 60 is removed, and an electrode composed of the chromium layer 41 and the gold layer 47 is formed.

Next, unnecessary portions of the gold layer 47 are removed to expose the chromium layer 41. As shown in FIG. 6D, after the photoresist 63 which is the second mask is formed on the surface of the gold layer 47, the portion where the gold layer 47 is left (in this example, the portion where the frequency adjustment electrode 38 is formed). The photoresist 63 is left so as to remain (also referred to as exposure), followed by development. In FIG. 6D, the portion where the photoresist 63 does not remain is represented by a two-dot chain line.
Subsequently, the gold layer 47 is etched using the photoresist 63 as a mask. By this etching process, the gold layer 47 in the region excluding the frequency adjusting electrode 38 is removed, the chromium layer 41 is exposed, and the photoresist 63 is removed, whereby as shown in FIG. Is a one-layer electrode of the chromium layer 41, and the frequency adjusting electrode 38 is a two-layer electrode of the chromium layer 41 and the gold layer 47.

  Next, a weight metal layer 49 is formed on the surface of the gold layer 47 of the frequency adjusting electrode 38. As shown in FIG. 6F, the surfaces of the chromium layer 41 and the gold layer 47 exposed in the above-described process are covered with a metal mask 64 which is a third mask. The metal mask 64 is provided with a window opening 65 at a portion corresponding to the weight metal layer 49. Subsequently, gold (Au) is vacuum-deposited so as to cover the metal mask 64, and the weight metal layer 49 is formed in the window opening portion 65.

  Next, as shown in FIG. 6G, the weight metal layer 49 is exposed on the surface of the frequency adjusting electrode 38 by removing the metal mask 64.

According to such a method of manufacturing a quartz crystal vibrating piece, the connection electrode 34 made of a chromium layer is formed on the surface of the tuning fork type quartz crystal vibrating piece 2, and the frequency adjusting electrode 38 is formed by a gold layer 47 provided to overlap the chromium layer 41. Thus, the weight adjusting metal layer 49 can be formed on the frequency adjusting electrode 38. Accordingly, it is possible to ensure the conductivity of the connection electrode 34. In addition, since the gold layer 47 is made of gold, which is less susceptible to chemical changes (particularly oxidation phenomenon), even if the weight metal layer 49 is provided on the surface of the gold layer 47, the adhesion deteriorates due to oxidation or the like. The quartz crystal vibrating piece 2 that can be prevented can be provided. That is, in the crystal resonator 1 using the crystal resonator element 2 of the present invention, the reliability of the connection electrode 34 is improved and the adhesion of the weight metal layer 49 is secured, whereby the weight metal layer 49 is peeled off. Thus, it is possible to provide the crystal resonator 1 that can prevent the frequency change due to the above and stabilize the frequency for a long period of time, in other words, the long-term reliability.
(Third embodiment)

  A method for manufacturing a quartz crystal resonator element according to a third embodiment of the present invention will be described with reference to the drawings, taking a method for manufacturing a tuning fork type crystal resonator as an example. FIG. 7 is a diagram showing a process flow for forming an electrode of a tuning fork type crystal vibrating piece, where the BB cross section shows the base portion 21 and the CC cross section shows the frequency formed at the tip portions of the arm portions 22 and 23. The part of the adjustment electrode 38 is shown.

  As in the second embodiment, the tuning fork type crystal vibrating piece 2 is manufactured by forming the outer shape of the crystal vibrating piece prior to the formation of the electrode. explain. In the manufacturing process of the quartz crystal vibrating piece 2, electrodes are simultaneously formed on both the upper and lower surfaces of the quartz substrate, which is a piezoelectric base material, and the electrodes are similarly formed on the side surfaces.

  First, as shown in FIG. 7A, an electrode film is formed on the entire surface of the quartz crystal vibrating piece 2 formed with the outer shape (in FIG. 7, the tip portions of the base portion 21 and the arm portions 22 and 23 are shown). The chromium layer 41 which is the first metal layer constituting the film is formed. The chromium layer 41 is formed by vacuum sputtering or vacuum deposition.

  Next, the chromium layer 41 is divided to form respective electrode shapes. After a photoresist 70 as a first mask is formed on the surface of the chromium layer 41, baking is performed on each electrode shape (also referred to as exposure). Subsequently, development is performed to leave the photoresist 70 in the shape of each electrode as shown in FIG. The portion of the photoresist 70 where the electrodes are divided is a window opening 71 where the photoresist 70 does not exist.

  Next, the chromium layer 41 is etched using the photoresist 70 as a mask. By this etching process, the chromium layer 41 corresponding to the window opening 71 of the photoresist 70 is removed to form a gap 72 (also referred to as an electrode dividing line). As shown in FIG. Leave the shape corresponding to the electrode. Thereafter, the photoresist 71 is removed, and an electrode for the chromium layer 41 is formed.

  Next, a weight metal layer 49 is formed on the surface of the chromium layer 41 of the frequency adjusting electrode 38. As shown in FIG. 7D, the surface of the chromium layer 41 is covered with a metal mask 74 that is a second mask. The metal mask 74 is provided with a window opening 75 at a portion corresponding to the weight metal layer 49. Subsequently, gold (Au) is vacuum-deposited so as to cover the metal mask 74, and the weight metal layer 49 is formed in the window opening portion 75.

  Next, as shown in FIG. 7E, the metal mask 74 is removed to expose the weight metal layer 49 on the surface of the frequency adjustment electrode 38. In the base portion 21, the connection electrode 34 in which the chromium layer 41 is divided into electrodes by the gap portion 72 is exposed.

According to such a method of manufacturing a quartz crystal vibrating piece, the weight metal layer 49 of gold (Au) is directly formed on the surface of the chromium layer 41, so that it is possible to provide a manufacturing method in which the processing steps are shortened. That is, in addition to the effects of the second embodiment, it is possible to provide a cheaper crystal vibrating piece.
(Fourth embodiment)

A piezoelectric oscillator using the above-mentioned tuning fork type crystal resonator as an example of the piezoelectric resonator of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional perspective view of the piezoelectric oscillator of the present invention.
According to FIG. 8, the piezoelectric oscillator 100 of the present invention is electrically connected to a base 104 in, for example, a ceramic package 102 as a cage by a silicone-based conductive adhesive 106 or the like. It is fixed while taking. In addition, an oscillation circuit 108 that is electrically connected to the crystal vibrating piece 2 and has a function of operating at least the crystal vibrating piece 2 is fixed to the bottom 110 of the package 102. Here, the crystal resonator element 2 and the oscillation circuit 108 are in a position where they do not interfere with each other. Further, the lid body 112 is joined to the upper joint portion 114 of the package 102 to maintain airtightness.

  According to the present invention, since the above-described crystal resonator is used, it is possible to provide the piezoelectric oscillator 100 that is not hindered in energization even when connected using a silicone-based conductive adhesive and has improved long-term reliability at low cost. Is possible.

  In the above-described embodiment, the first metal layer has been described using chromium (Cr). However, the present invention is not limited to this, and the degree of adhesion between both a quartz crystal vibrating piece such as nickel (Ni) and gold is ensured. Any metal can be used.

  Moreover, although the metal which forms a weight metal layer was demonstrated with gold | metal | money (Au), it is not restricted to this, What is necessary is just a metal which can be fuse | melted for frequency adjustments, such as silver (Ag).

  In addition, the weight metal layer has been described with the structure formed on the front and back sides of the crystal vibrating piece. However, the present invention is not limited to this, and the weight metal layer is formed only on one side as long as it is possible to secure a mass capable of sufficient frequency adjustment. You can also.

1 is a schematic perspective view showing a crystal resonator according to a first embodiment. FIG. 2 is a cross-sectional view taken along the line PP in FIG. It is a perspective view of a crystal vibrating piece, (a) is a perspective view when seen from diagonally upward, and (b) is a perspective view when seen from diagonally below. It is side surface sectional drawing which shows typically each site | part of a crystal vibrating piece, (a) is sectional drawing of an arm part (AA cross section of Fig.3 (a)), (b) is sectional drawing of a base ( FIGS. 3A and 3B are cross-sectional views in the vicinity of the tip of the arm (CC cross-section in FIG. 3A). It is the top view and DD sectional view which show the modification of a connection electrode, (a)-(d) is a figure which shows the modification of each connection electrode, respectively. The figure which shows the process flow which forms the electrode of the crystal vibrating piece in 2nd embodiment among the manufacturing processes of a tuning fork type crystal resonator. The figure which shows the process flow which forms the electrode of the crystal vibrating piece in 3rd embodiment among the manufacturing processes of a tuning fork type crystal resonator. FIG. 3 is an exploded perspective view, partly broken, of a piezoelectric oscillator using a tuning fork type crystal resonator as an example of a piezoelectric resonator. FIG. 6 is a front sectional view showing a conventional piezoelectric vibrator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tuning fork type crystal resonator as a piezoelectric vibrator, 2 ... Tuning fork type crystal vibrating piece, 21 ... Base part, 22, 23 ... Arm part of piezoelectric vibrating piece, 30 ... Holder, 31 ... Holding part, 31a ... Metal wiring of holding part, 33 ... excitation electrode, 34 ... connection electrode, 35, 106 ... silicone conductive adhesive, 36 ... metal lid, 38 ... frequency adjusting electrode, 38a ... chrome as first metal layer 38b ... gold layer as the second metal layer, 38c ... weight metal layer as the third metal layer, 39 ... surface protective layer, 40 ... electrode pattern, 41 ... chromium layer, 45 ... excitation electrode, 47 ... gold layer , 49... Weight metal layer, 60 and 70... Photoresist as first mask, 61 and 71... Opening portion of resist mask, 62 and 72. 74 ... Metal mass as a third mask , 65, 75 ... Window opening of metal mask, 100 ... Piezoelectric oscillator, 102 ... Package as cage, 108 ... Oscillation circuit as circuit element, 251, 252, 253, 254 ... Edge of upper surface of piezoelectric vibrating piece 261, 262, 263, 264... Edge portions of the lower surface portion of the piezoelectric vibrating piece, 271, 272.

Claims (12)

A piezoelectric vibrating piece connected to a cage by a silicone-based conductive adhesive,
A tuning fork-shaped piezoelectric base material having a pair of arm portions as vibration portions;
An excitation electrode formed by a first metal layer made of a chromium-based or nickel-based metal provided across the arm portion on the surface of the piezoelectric substrate;
A connection electrode formed by the first metal layer provided in connection with the excitation electrode on the base side surface of the piezoelectric substrate;
The piezoelectric vibrating piece, wherein the first metal layer exposed at least partially on the surface of the connection electrode is bonded and fixed to the retainer at a base portion thereof in a state where the first metal layer is bonded to the silicone-based conductive adhesive. The piezoelectric vibrating piece according to claim 1,
The piezoelectric vibrating piece according to claim 1, wherein the connection electrode is formed only of the first metal layer. In the piezoelectric vibrating piece according to any one of claims 1 and 2,
A piezoelectric vibrating piece, wherein an insulating surface protective layer is formed so as to cover at least the excitation electrode. The piezoelectric vibrating piece according to any one of claims 1 to 3,
The connection electrode includes the first metal layer and the second metal layer provided to overlap a part of the first metal layer. The piezoelectric vibrating piece according to claim 4,
The piezoelectric vibrating piece according to claim 1, wherein the connection electrode is formed of the second metal layer in the vicinity of the outer edge of the connection electrode and the first metal in the center of the connection electrode. The piezoelectric vibrating piece according to claim 1,
For frequency adjustment, at least a portion of the first metal layer and a second metal layer provided on the first metal layer in a portion of the pair of arms of the piezoelectric base material on the tip side of the excitation electrode. A piezoelectric vibrating piece in which an electrode is formed. The piezoelectric vibrating piece according to claim 6,
2. The piezoelectric vibrating piece according to claim 1, wherein the second metal layer is made of gold, and the frequency adjusting electrode further includes a frequency adjusting weight metal layer formed on a surface of the second metal layer. A cage,
The piezoelectric vibrating piece according to any one of claims 1 to 7, which is connected to the cage.
The first metal layer exposed at least partially on the surface of the connection electrode of the piezoelectric vibrating piece is bonded and fixed to the retainer at a base portion thereof in a state where the first metal layer is bonded to the silicone-based conductive adhesive. Piezoelectric vibrator. On the surface of the piezoelectric substrate, at least an excitation electrode for oscillating the piezoelectric substrate, a connection electrode connected to the excitation electrode and connected to the cage, and a frequency adjustment for adjusting the oscillation frequency of the piezoelectric substrate And a method for producing a piezoelectric vibrating piece having
Forming on the surface of the piezoelectric substrate an electrode film comprising a first metal layer of chromium or nickel and a second metal layer of gold covering the surface of the first metal layer;
Providing a first mask on the surface of the electrode film, removing the portion of the electrode film that is not covered with the first mask, and dividing the electrode film;
A step of providing a second mask covering the frequency adjusting electrode, removing at least the second metal layer of the excitation electrode and the connection electrode, which is not covered by the second mask, and exposing the first metal layer; When,
Providing a third mask that covers a region excluding the frequency adjustment electrode, and forming a weight adjustment weight metal layer over the frequency adjustment electrode that is not covered by the third mask. A method of manufacturing a piezoelectric vibrating piece. On the surface of the piezoelectric substrate, at least an excitation electrode for oscillating the piezoelectric substrate, a connection electrode connected to the excitation electrode and connected to the cage, and a frequency adjustment for adjusting the oscillation frequency of the piezoelectric substrate A method of manufacturing a piezoelectric vibrator having a working electrode,
Forming a chromium or nickel first metal layer on the surface of the piezoelectric substrate;
A step of providing a first mask on the surface of the first metal layer, removing the portion of the first metal layer not covered with the first mask, and dividing it into the respective electrodes;
Providing a third mask that covers a region excluding the portion of the frequency adjustment electrode, and forming a weight metal layer for frequency adjustment over the first metal layer not covered by the third mask; A method of manufacturing a piezoelectric vibrating piece, comprising: A cage for holding the piezoelectric base material in a connected state, an excitation electrode for oscillating at least the piezoelectric base material on the surface of the piezoelectric base material, a connection to the excitation electrode, and a connection to the cage A method of manufacturing a piezoelectric vibrator having a connection electrode and a frequency adjusting electrode for adjusting an oscillation frequency of the piezoelectric substrate,
The piezoelectric vibrating piece manufactured by the method of manufacturing a piezoelectric vibrating piece according to claim 9 or 10 is bonded and fixed to the cage at a base portion using a silicone-based conductive adhesive, and the connection electrode A piezoelectric vibrator comprising: a step of electrically connecting the connection electrode and the cage in a state in which the first metal layer exposed on the surface and the silicone-based conductive adhesive are bonded to each other. Production method. A cage,
The piezoelectric vibrating piece according to any one of claims 1 to 7, connected to the cage by a silicone-based conductive adhesive,
A circuit element having a function of oscillating at least the piezoelectric vibrating piece,
The first metal layer exposed at least partially on the surface of the connection electrode of the piezoelectric vibrating piece is bonded and fixed to the retainer at a base portion thereof in a state where the first metal layer is bonded to the silicone-based conductive adhesive. Piezoelectric oscillator.

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