JP2013207646A - Piezoelectric vibration device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration device which prevents the occurence of cracks due to a thermal expansion coefficient difference and achieves high airtight reliability, and to provide a manufacturing method of the piezoelectric vibration device.SOLUTION: A crystal resonator 1 of this invention comprises: a lid 4; a crystal vibration piece 3; and a container 2 housing the crystal vibration piece 3. A resin film for printing 9 is formed on one main surface 41 of the lid 4, and a stress relaxation film 10 for relaxing stress applied on the lid 4 is formed on the other main surface 42 facing the one main surface 41.

Description

  The present invention relates to a piezoelectric vibration device used for communication equipment and the like, and a method for manufacturing the piezoelectric vibration device.

  In recent years, high-density mounting due to miniaturization and multifunctionalization of mobile phones and mobile communication devices has progressed, and piezoelectric vibration devices mounted on these devices and the like are also extremely small (for example, external dimensions of a piezoelectric vibration device having a rectangular shape in plan view). Is 2.0 mm × 1.6 mm or less) and an ultra-thin one has been demanded. Taking a crystal resonator as an example of the piezoelectric vibration device, the crystal resonator is bonded to the container through a crystal vibrating piece, a container having a recess for housing the crystal vibrating piece, and a bonding material so as to cover the recess. The lid is the main component.

  In order to meet the demand for ultra-small and ultra-thin piezoelectric vibration devices, glass and quartz may be used for the base material of the main constituent member. For example, when the lid is made of a light-transmitting material such as glass, there is a possibility that various characteristics of the piezoelectric vibration device are adversely affected by transmission of light from the outside into the piezoelectric vibration device. Therefore, for example, Patent Literature 1 discloses a piezoelectric vibration device in which a light shielding film is provided on the surface of a lid made of a light-transmitting material.

  In addition, in a miniaturized piezoelectric vibration device, when the lid is made of a light-transmitting material such as glass, the laser beam is transmitted through the inside of the lid, even if it is a laser marker suitable for printing in a minute area. Resulting in. For this reason, for example, Patent Document 2 discloses a method in which a light shielding film is provided on the side of the lid facing the internal space of the piezoelectric vibration device and printing is performed using the light shielding film.

JP 2007-181130 A JP 2010-057011 A

  However, in Patent Document 1, a light shielding layer is formed only on the main surface side exposed to the outside of the lid. This light shielding layer is composed of a metal layer or a resin layer, and has a thermal expansion coefficient different from that of glass which is a base material of the lid. As a result, a difference occurs in the thermal stress generated by the heat treatment in the manufacturing process of the piezoelectric device, and cracks and the like are likely to occur. This becomes more prominent when the base of the lid or container is made of a brittle material such as glass. In Patent Document 2, a light shielding film made of metal is provided only on the side of the lid facing the internal space of the piezoelectric device. The light shielding film is made of metal and has a thermal expansion coefficient different from that of a lid made of a transparent material (quartz). As a result, a difference occurs in the thermal stress generated by the heat treatment in the manufacturing process of the piezoelectric device as described above, and cracks and the like are likely to occur. Further, when the lid is warped due to the difference in the thermal stress, the stress is also transmitted to the bonding material interposed between the lid and the container, cracks or the like may occur, and airtightness may not be ensured.

  The present invention has been made in view of the above points, and provides a piezoelectric vibration device having high hermetic reliability and a method for manufacturing the piezoelectric vibration device that prevents occurrence of cracks and the like due to a difference in thermal expansion coefficient. It is the purpose.

  In order to achieve the above object, the present invention provides a piezoelectric vibrating device in which a lid and at least a container that accommodates a piezoelectric vibrating piece are bonded to each other on one main surface exposed to the outside of the lid. A printing resin film is formed, and a piezoelectric vibration device is formed in which a stress relaxation film is formed on the other main surface of the lid opposite to the one main surface to relieve stress on the lid.

  According to the above invention, the printing resin film is formed on one main surface exposed to the outside of the lid, and the stress on the lid is relieved on the other main surface of the lid facing the one main surface. The stress relaxation film is formed. With such a configuration, it is possible to relieve stress due to expansion or contraction caused by a difference in thermal expansion coefficient. As a result, the occurrence of cracks and the like in the piezoelectric vibration device can be suppressed. When glass, crystal, or the like is used for the base material of the lid, the lid surface can be protected by forming a resin film on one main surface exposed to the outside of the lid. It also functions as a light-shielding film for a translucent lid such as glass or quartz. Furthermore, since a printing resin film is formed on one main surface exposed to the outside of the lid, the resin film can be used as a base layer for printing products.

  In order to achieve the above object, the stress relaxation film may be a gas adsorption film made of metal. According to the above invention, for example, the thermal stress caused by the difference in thermal expansion coefficient generated by forming a printing resin film on one main surface of a lid made of ceramic or the like is alleviated by the gas adsorption film made of metal. Can do. Furthermore, the gas generated by the heat treatment in the manufacturing process can be adsorbed by the gas adsorption film. The gas adsorption film made of metal is a porous metal film called a so-called getter film, and therefore has a large surface area, and gas molecules are chemically adsorbed by the vacancies in the adsorption film and are not easily desorbed. That is, even if the atmosphere (pressure) in the internal space of the piezoelectric vibration device changes, the chemical adsorption of gas molecules in the adsorption film is irreversible, so that the long-term stability of the characteristics of the piezoelectric vibration device is excellent.

  In order to achieve the above object, the lid is made of a translucent material, and the piezoelectric vibrating piece has a frequency adjustment region made of a metal film in which frequency adjustment is performed by irradiation of a beam from the outside of the lid. The beam passage hole may be formed in a region corresponding to the frequency adjustment region of the stress relaxation film.

  According to the said invention, the frequency adjustment using a beam can be performed after joining a cover body and a container. This is because the lid is made of a translucent material and a beam passage hole is formed in the stress relaxation film. That is, the beam passes through the inside of the lid, passes through the passage hole of the stress relaxation film, and is irradiated to the frequency adjustment region made of the metal film provided on the piezoelectric vibrating piece.

  In the manufacture of a conventional piezoelectric vibration device, the frequency adjustment is generally performed before the lid is joined to the container. That is, in this order, the frequency of the piezoelectric vibrating piece accommodated in the container is adjusted by irradiating the metal film for frequency adjustment with a beam, and then the lid and the container are joined. In this case, the fluctuation amount of the frequency generated by the joining process of the lid and the container tends to be larger than the fluctuation amount of the frequency in the other manufacturing process, and even if the frequency distribution is narrowed down in the frequency adjusting process, the joining process is performed. As a result, there is a problem that the frequency distribution is expanded.

  In contrast, with the piezoelectric vibrating device of the present invention, the frequency adjustment using the beam is performed after the lid is bonded to the container containing the piezoelectric vibrating piece having the frequency adjustment region, so that the expansion of the frequency distribution is suppressed. can do. Further, according to the piezoelectric vibration device of the present invention, the stress relaxation film is formed with a beam passage hole corresponding to the frequency adjustment region, so that the frequency adjustment by the beam can be performed from the outside of the lid after joining the lid and the container. In addition to being possible, the stress applied to the lid by forming the resin film for printing on one main surface exposed to the outside of the lid can be relieved by the stress relaxation film formed on the other main surface.

  In order to achieve the above object, in the printing resin film, an opening for passing the beam is formed at a position overlapping the passage hole of the stress relaxation film in plan view, and the opening is formed by the printing resin. It may be filled with a film.

  According to the above invention, the frequency adjustment by the beam can be performed in a state closer to the final form. This is due to the following reason. After the lid made of a translucent material is joined to the container, a printing resin film is formed in advance on the upper surface of the lid before adjusting the frequency. Here, an opening for allowing the beam to pass through is formed in the printing resin film at a position overlapping the passage hole of the stress relaxation film in plan view. When the beam is irradiated from the outside of the lid toward the frequency adjustment region of the piezoelectric vibrating piece accommodated in the container, there is no film that shields or absorbs the beam in the irradiation region. The beam can reach the frequency adjustment region of the piezoelectric vibrating piece. As described above, the opening is a region corresponding to the frequency adjustment region of the piezoelectric vibrating piece. For example, when a tuning-fork type crystal vibrating piece having a pair of vibrating arms is used as the piezoelectric vibrating piece, the frequency adjustment region is provided in a narrow region near the tip of the vibrating arm. In other words, the opening corresponding to the frequency adjustment region is also a narrow region, and the frequency adjustment is performed in a state close to a state in which the printing resin film is formed on the entire upper surface of the lid, which is the final form of the piezoelectric vibration device before printing. be able to. After the frequency adjustment is completed, the opening is sealed with resin, and a piezoelectric vibration device is completed through a predetermined process. Thereby, expansion of frequency distribution can be suppressed.

In order to achieve the above object, a method of manufacturing a piezoelectric vibration device in which a lid and a container in which at least a piezoelectric vibration piece is accommodated are joined,
A mounting step of mounting a piezoelectric vibrating piece having a frequency adjustment region made of a metal film on which frequency adjustment is performed on a container;
A stress relaxation film forming step of forming a stress relaxation film having a beam passage hole corresponding to the frequency adjustment region on a main surface of the lid made of a light-transmitting material to be bonded to the container;
A joining step for joining the lid and the container;
A frequency adjustment step of adjusting the frequency by irradiating a beam from the outside of the lid, passing through the inside of the lid and the inside of the passage hole, and reducing the metal film in the frequency adjustment region;
A resin film forming step of forming a resin film for printing on one main surface exposed to the outside of the lid;
A printing step of printing on the surface of the printing resin film;
A method of manufacturing a piezoelectric vibrating device having

  According to the manufacturing method described above, the stress relaxation film is formed on the other main surface of the lid that faces the one main surface in the stress relaxation film forming step. In the resin forming step, a printing resin film is formed on one main surface exposed to the outside of the lid made of a translucent material. The printing resin film and the stress relaxation film formed in these steps can relieve stress due to expansion and contraction due to the difference in thermal expansion coefficient. As a result, the occurrence of cracks and the like in the piezoelectric vibration device can be suppressed. In addition, when glass or crystal is used as the base material of the lid as a translucent material, the surface of the lid is protected by forming a resin film on one main surface exposed to the outside of the lid. Can do. It also functions as a light shielding film for a light-transmitting lid such as glass or quartz. Furthermore, since a printing resin film is formed on one main surface exposed to the outside of the lid, the resin film can be used as a base layer for printing products.

  According to the manufacturing method, frequency adjustment using a beam can be performed after the joining step. This is because the lid is made of a translucent material and a beam passage hole is formed in the stress relaxation film. That is, the beam passes through the inside of the lid, passes through the passage hole of the stress relaxation film, and is irradiated to the frequency adjustment region made of the metal film provided on the piezoelectric vibrating piece. By such a manufacturing method, the expansion of the frequency distribution due to the joining of the lid and the container can be suppressed. Further, according to the above manufacturing method, the stress generated by forming the printing resin film on one main surface exposed to the outside of the lid in the resin film forming step is formed on the other main surface opposite to the one main surface. Can be relaxed by the applied stress relaxation film.

  As described above, according to the present invention, it is possible to provide a piezoelectric vibration device and a method for manufacturing the piezoelectric vibration device that prevent occurrence of cracks and the like due to a difference in thermal expansion coefficient and have high hermetic reliability.

Schematic cross-sectional view of a crystal resonator representing an embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention Sectional schematic diagram showing the manufacturing method of the crystal oscillator in the embodiment of the present invention

Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking a crystal resonator as an example of a piezoelectric vibration device. First, a crystal resonator in a finished product will be described, and then a method for manufacturing the crystal resonator will be described.
FIG. 1 shows a schematic cross-sectional view of a crystal resonator showing an embodiment of the present invention. In FIG. 1, the crystal unit 1 has a substantially rectangular parallelepiped shape, and is a surface mount type suitable for low profile. The crystal resonator 1 includes a crystal vibrating piece 3, a container 2 that houses the crystal vibrating piece 3, and a lid 4 that is joined to the container 2 as main components. The crystal vibrating piece 3 is accommodated in an internal cavity 15 formed by joining the lid 4 and the container 2 and is protected from the external environment.

  In FIG. 1, the container 2 is a box-shaped body made of borosilicate glass as a base material. In the container 2, a rectangular accommodating portion 20 in which the crystal vibrating piece 3 is accommodated is formed by photolithography technique and wet etching (wet etching). And the bank part 24 is shape | molded so that the accommodating part 20 may be surrounded. A step portion 25 is formed on the inner bottom surface 21 of the housing portion 20 along the entire end portion in the longitudinal direction. A plane that is one step lower than the step portion 25 is the deepest portion of the housing portion 20. The base material portion sandwiched between the inner bottom surface 21 and the outer bottom surface 22 facing the housing portion 20 is referred to as a bottom plate portion 23 for convenience of explanation. Since the base material of the container 2 is glass, the side surface of the region dug by wet etching is an inclined surface (the inner side surface 241 of the bank portion 24, the side surface of the step portion 24, the peripheral edge of the outer bottom surface 22 of the container) Part etc.).

  In FIG. 1, a pair of mounting electrodes 5 and 5 that are cantilevered with one end side of the crystal vibrating piece 3 via the joining member 6 are formed on the upper surface 250 of the step portion 25. The mounting electrode 5 is electrically connected to one end portion of the internal wiring pattern 50, and passes through a through electrode (not shown) penetrating the bottom plate portion 23, an external wiring pattern (not shown) on the outer bottom surface 22 of the container, and the like. The external connection terminal 7 is led out.

  The gas adsorption film 12 is formed on the inner bottom surface 21 of the accommodating portion 20 including the step portion 25 and the inner side surface 241 of the bank portion 24. The gas adsorption film 12 is made of a titanium film formed on the base material of the container 2 by sputtering (so-called getter film). The gas adsorption film 12 is provided with a gap from the mounting electrode 5 and the internal wiring pattern 50, thereby preventing a short circuit between the mounting electrode 5 and the internal wiring pattern 50 and the gas adsorption film 12.

  A first bonding layer (81 shown in FIG. 2) made of a metal laminated film is formed in a circumferential shape on the upper surface 240 of the bank portion 24. The film structure of the first bonding layer is the same as that of the internal wiring pattern 50. It is the same. In the present embodiment, the film structure of the first bonding layer has a structure in which a sputtered film (film formed by sputtering) and a plating film are sequentially stacked. The plating film is composed of a plurality of plating layers, and a Cu plating film, a Ni plating film, an Au strike plating film or a Pd plating film, and an Au plating film are laminated on the sputtered film in this order. In FIG. 1, the first bonding layer 81, the second bonding layer formed on the lid, which will be described later, and the bonding material between the first bonding layer and the second bonding layer are integrated by heating and melting. A thing is represented as a bonding material 8.

  In FIG. 1, a crystal vibrating piece 3 is a tuning-fork type crystal vibrating piece having a base (not shown) and a pair of vibrating arms (not shown) extending in one direction from the base (in FIG. 1, the crystal vibrating piece is shown). Simplified notation). In the crystal vibrating piece 3, the base portion is cantilevered to the step portion 25, and the region of the inner surface 21 of the concave portion facing the tips of the pair of vibrating arms serving as free ends is formed thinner than the step portion 25. The application of the present invention is not limited to a tuning-fork type crystal vibrating piece, but can also be applied to piezoelectric vibrating pieces of other shapes.

  An electrode pattern (not shown) having a predetermined shape for driving the tuning fork type crystal vibrating piece is formed on the base portion of the crystal vibrating piece 3 and the front and back side surfaces of the vibrating arm by a photolithography technique. The electrode pattern has a different polarity and is led out to the base side as a pair of connection electrodes (not shown). The bonding members 6 and 6 are arranged so that the pair of connection electrodes correspond to the pair of mounting electrodes 5 and 5 of the container 2. 6 are electrically conductively joined. A frequency adjustment region 30 made of a metal film for frequency adjustment is formed at the tip portions of the pair of vibrating arms. In this embodiment, gold is used as a metal film for frequency adjustment.

  In the present embodiment, a conductive plating bump is used for the bonding member 6, and is formed in advance on each of the pair of connection electrodes of the crystal vibrating piece 3. Then, after the crystal vibrating piece 3 is positioned and placed on the step portion 25 so that the pair of plating bumps correspond to the pair of mounting electrodes 5 and 5, the crystal vibrating piece 3 is formed by FCB (Flip Chip Bonding) method. Is joined to the container 2. The joining of the crystal vibrating piece 3 and the container 2 is not limited to the FCB method. For example, a method of joining by heating and curing using a conductive adhesive as a joining member or other joining methods may be used. Good.

  In FIG. 1, the lid 4 is substantially rectangular in plan view and is made of glass. One main surface 41 of the lid 4 is a flat surface, and a wall portion 43 protruding downward is formed in an annular shape on the peripheral portion of the other main surface 42 facing the one main surface 41. The wall portion 43 is formed at the outer edge on the side of the joint surface with the container 2, and an inclined surface 431 inclined inward from the outer surface 44 is formed at the outer edge. The inclined surface 431 is formed by wet etching. A second bonding layer (not shown) is formed on the inclined surface 431 on the bonding surface of the wall 43 with the container 2 (wall upper surface 430). The second bonding layer has a structure in which a sputtered film made of Au is laminated on the stress relaxation film 10. A sputtered film made of Cu may be used instead of the sputtered film of Au. In this embodiment, glass is used for the base material of the lid, but quartz or ceramic may be used in addition to glass.

  A printing resin film 9 is formed on one main surface 41 and the outer surface 44 of the lid 4. In this embodiment, a solder resist, which is an epoxy resin, is used for the printing resin film 9. In the present embodiment, the printing resin film is formed on one main surface and the outer surface of the lid, but the printing resin film may be formed only on one main surface of the lid. The printing resin film is not limited to a solder resist, and other insulating resin materials may be used. For example, white ink made of epoxy resin (so-called white ink) can also be used. In addition to the epoxy resin, a polyimide resin may be used. In this case, PBO or photosensitive polyimide can be used as the polyimide resin.

  On the other main surface 42 of the lid body 4 and the surface of the wall portion 43, a stress relaxation film 10 for relaxing stress applied to the lid body 4 is formed. The stress relaxation film 10 is a gas adsorption film made of metal, and has both a stress relaxation function and a gas adsorption function. A passage hole 11 is formed in the stress relaxation film 10 at a position corresponding to the frequency adjustment region 30. The passage hole 11 is a hole for allowing a beam irradiated from the outside of the lid body to pass through in a frequency adjusting step described later.

  According to the above configuration, the printing resin film 9 is formed on the one main surface 41 exposed to the outside of the lid 4, and the other main surface 42 of the lid opposing the one main surface 41 extends to the lid. A stress relaxation film 10 for relaxing stress is formed. With such a configuration, it is possible to relieve stress due to expansion or contraction caused by a difference in thermal expansion coefficient. As a result, the occurrence of cracks and the like in the crystal resonator can be suppressed. When glass or crystal is used for the base material of the lid as in this embodiment, the lid surface is protected by forming a resin film on one main surface exposed to the outside of the lid. Can do. It also functions as a light-shielding film for a translucent lid such as glass or quartz. Furthermore, since the printing resin film 9 is formed on the one main surface 41 exposed to the outside of the lid 4, the resin film can be used as a base layer for product printing.

  Moreover, according to the said structure, the thermal stress resulting from the thermal expansion coefficient difference which generate | occur | produces by forming the resin film for printing on the one main surface of the cover body which consists of ceramics etc. is relieve | moderated by the gas adsorption film which consists of metals. be able to. Furthermore, the gas generated by the heat treatment in the manufacturing process can be adsorbed by the gas adsorption film. The gas adsorption film made of metal is a porous metal film called a so-called getter film, and therefore has a large surface area, and gas molecules are chemically adsorbed by the vacancies in the adsorption film and are not easily desorbed. In other words, even if the atmosphere (pressure) in the internal space of the crystal unit is changed, the chemical adsorption of gas molecules in the adsorption film is irreversible, so that the long-term stability of the characteristics of the crystal unit is excellent.

  Moreover, according to the said structure, the frequency adjustment using a beam can be performed after joining the cover body 4 and the container 2. FIG. This is because the lid 4 is made of a translucent material, and the beam passage hole 11 is formed in the stress relaxation film 10. That is, the beam passes through the inside of the lid body 4, passes through the inside of the passage hole 11, and is irradiated to the frequency adjustment region 30 made of the metal film provided on the crystal vibrating piece 3.

  In the manufacture of a conventional piezoelectric vibration device, the frequency adjustment is generally performed before the lid is joined to the container. That is, in this order, the frequency of the piezoelectric vibrating piece accommodated in the container is adjusted by irradiating the metal film for frequency adjustment with a beam, and then the lid and the container are joined. In this case, the fluctuation amount of the frequency generated by the joining process of the lid and the container tends to be larger than the fluctuation amount of the frequency in the other manufacturing process, and even if the frequency distribution is narrowed down in the frequency adjusting process, the joining process is performed. As a result, there is a problem that the frequency distribution is expanded.

  On the other hand, in the case of the crystal resonator of the present invention, the frequency distribution using the beam is performed after the lid 4 is bonded to the container 2 in which the crystal vibrating piece 3 having the frequency adjustment region 30 is accommodated. Can be suppressed. Furthermore, according to the crystal resonator of the present invention, the stress relaxation film 10 is formed with the beam passage hole 11 corresponding to the frequency adjustment region 30, so that the beam is applied from the outside of the lid after joining the lid and the container. In addition to being able to adjust the frequency, the stress applied to the lid by forming the resin film for printing on one main surface 41 exposed to the outside of the lid 4 is caused by the stress relaxation film 10 formed on the other main surface 42. Can be relaxed.

  In FIG. 1, the printing resin film 9 is formed so as to continuously cover the outer side surface 44 of the lid, the outer edge portion of the stress relaxation film, and the outer edge portion of the bonding material 8, and the bonding between the lid body and the container. In the vicinity of the region, the printing resin film is formed in a state of being depressed inward (in the direction of the internal cavity 15) (depression 13).

A bonding material (not shown) for bonding the container 2 and the lid body 4 is laminated on the second bonding layer of the lid body 4. The film structure of the bonding material is a structure in which an Au strike plating film and an Au plating film are laminated in this order on an Au / Sn film plating film. With the above structure, the Au / Sn film is melted by heating to become an AuSn alloy film. Note that the AuSn alloy film may be formed on the second bonding layer from the beginning without forming the AuSn alloy by heating and melting. Further, the bonding material may be formed on the container side, that is, on the first bonding layer, without being formed on the lid side.
This completes the description of the crystal unit in the finished product state. Next, a method for manufacturing a crystal resonator according to the present invention will be described with reference to FIGS.

-Mother board formation process-
First, as shown in FIG. 2, a container base substrate 200 in which a plurality of containers are arranged in a matrix direction is formed. First, one wafer made of borosilicate glass is prepared, and the main surfaces of the one main surface 201 and the other main surface 202 are thinned into a predetermined shape by using a photolithography technique and wet etching. That is, with respect to one main surface 201, a step portion 25, a thin region below the step portion, a through hole (not shown in FIG. 2) for forming a through electrode, and the like are formed. On the other hand, with respect to the other main surface 202, the recessed portion 27 is formed so as to straddle the boundary line L between adjacent container forming regions (regions represented as “one section” in FIG. 2).

  After the step 25, the through hole, the recessed portion 27 and the like are formed, the internal wiring pattern 50, the first bonding layer 81, the external wiring pattern, the external connection terminal 7 and the like are formed by a film forming unit. In FIG. 2, the external wiring pattern and the second sputtered film are not shown.

-Mounting process-
Next, the quartz crystal resonator element 3 is positioned and mounted on the mounting electrode 5 formed in each container of the container mother substrate 200 so that one end portion (the base portion described above) of the tuning fork type crystal resonator element 3 corresponds. I will do it. At this time, a bonding member 6 made of a plating bump is formed in advance on the connection electrode (not shown) of the crystal vibrating piece 3. Then, the crystal vibrating piece 3 is conductively joined to the container 2 by the FCB method. FIG. 3 shows a state after bonding of the plurality of crystal vibrating pieces 3, 3,...

-Stress relaxation film formation process-
In a separate process, the lid 4 having the shape shown in FIG. 1 is formed using photolithography and wet etching. And the stress relaxation film | membrane 10 is formed into a film by sputtering over the whole other main surface 42 of the cover body 4 (refer FIG. 1; illustration is abbreviate | omitted in description of a manufacturing method). Specifically, the stress relaxation film 10 includes the entire region excluding the passage hole 11 in the region facing the internal cavity 15 of the other main surface 42 of the lid 4, and the wall portion upper surface 430 from the inner surface of the wall portion 43. And the inclined surface 431 is formed. In the present embodiment, the resin film for printing is formed extending to one main surface 41 and the outer side surface 44 of the lid body 4, the inclined surface 431, and a region close to the other main surface 42 of the lid body. On the other hand, the stress relaxation film 10 extending to the inclined surface 431 is formed on the other main surface 42 side of the lid. Thus, by forming the stress relaxation film on the other main surface side of the lid, the stress applied to the lid due to the formation of the printing resin film on the lid can be effectively relaxed.

  The passage hole 11 is formed at a position corresponding to the frequency adjustment region 30 of the crystal vibrating piece 3. The passage hole 11 is formed by using a mask set in a predetermined shape, and is a hole for allowing a beam irradiated from the outside of the lid body to pass through in a frequency adjustment step described later.

  In this embodiment, a gas adsorption film (so-called getter film) made of titanium (Ti) is used for the stress relaxation film 10. In addition, when using the gas adsorption film | membrane which consists of a metal as a stress relaxation film | membrane, you may use not only Ti but another porous metal material. In the present embodiment, the stress relaxation film 10 is formed on the entire other main surface 42 of the lid 4, but the stress relaxation film may not be formed on the entire other main surface of the lid. For example, it may be formed only in the region facing the internal cavity 15 of the other main surface 42 of the lid 4. Since the stress relaxation film 10 made of Ti can adsorb the gas generated in the internal cavity 15 by heat applied in the joining process described later, a crystal resonator excellent in long-term stability can be provided. Further, the thermal stress caused by the difference in thermal expansion coefficient generated by forming the printing resin film 9 on the one main surface 41 of the lid 4 can be alleviated.

-Joining process-
Next, as shown in FIG. 4, the crystal vibrating piece 3 is hermetically sealed by bonding the lid 4 to each container after the mounting process via the bonding material 8. Specifically, the lid 4 is connected to the ridge of each container so that the bonding material on the second bonding layer formed on the bonding surface of the lid 4 with the container corresponds to the first bonding layer 81 of each container 2. Positioned and mounted on the part 24. Then, the first bonding layer, the second bonding layer, and the bonding material are integrated by welding in an atmosphere set to a predetermined temperature, and the lid 4 and the container 2 are bonded in an airtight manner. The crystal vibrating piece is hermetically sealed in the internal cavity 15 by joining the lid 4 and the container 2.

-Frequency adjustment process-
Next, as shown in FIG. 5, the beam R is irradiated from the outside of the lid joined to the container. Specifically, the beam is irradiated so that the beam passes through the inside of the lid 4 made of a translucent material and passes through the inside of the through hole 11 formed in the stress relaxation film. At this time, since the passage hole 11 is formed at a position corresponding to the frequency adjustment region 30, the beam is irradiated to the metal film in the frequency adjustment region 30 of the crystal vibrating piece 3 formed in the internal cavity 15. Frequency adjustment is performed by irradiating the metal film in the frequency adjustment region 30 with a beam. In the frequency adjustment, the beam is scanned so as to traverse in the width direction of the vibrating arm, and the beam is scanned while moving from the tip side to the root side of the vibrating arm in the frequency adjusting region. This is done by reducing the mass of the membrane. In this embodiment, a green laser is used as the beam. However, when a laser beam is used, a laser having a wavelength other than the green laser may be used. For example, a YAG laser or a carbon dioxide laser can also be used.

-Resin film formation process-
Next, as shown in FIG. 6, the printing resin film 9 is formed so as to cover the upper surface (one main surface 41) of each lid of the container mother substrate 200 and the inner peripheral surface of the gap between the adjacent lids. Arrange. In this embodiment, a solder resist which is an epoxy resin is used as a printing resin film. The printing resin film is not limited to the solder resist, and other resins may be used. For example, white ink made of epoxy resin (so-called white ink) can also be used. In addition to the epoxy resin, a polyimide resin may be used for the printing resin film. In this case, PBO or photosensitive polyimide can be used as the polyimide resin. In the present embodiment, the printing resin film 9 is formed with a thickness of about 0.005 to 0.02 mm.

  The aforementioned “gap” between the lids is the gap 14 shown in FIG. The gap 14 includes side surfaces of the outer side surfaces 44 and 44 of the facing lids, the inclined surfaces 431 and 431 of the wall portion 43, and the outer edge portion of the bonding material 8. , A recess having an inner bottom surface in a region between the opposing side wall portions. In the present embodiment, a coating resin material such as a spray coater or a curtain coater is used to apply the printing resin material to the inner peripheral surface of the gap 14. In this embodiment, the printing resin material is arranged so as not to fill the gap 14. After the printing resin material is cured, the printing resin film 9 is formed on the inner peripheral surface of the gap 14 as shown in FIG. Is in a state of wearing.

  In the present embodiment, the cover of translucent material is used and the order of passing through the resin film forming process after the frequency adjusting process is used, but the order of passing through the frequency adjusting process after the resin film forming process may be used. In this case, by forming an opening for allowing the beam to pass through the printing resin film in advance, the frequency adjustment by the beam can be performed in a state closer to the final form of the crystal resonator. The opening may be filled with a resin material after the frequency adjustment step.

-Printing process-
Next, as shown in FIG. 7, the printing resin film 9 formed on the one principal surface 41 of the lid is used as a base layer, and the printing resin film on the one principal surface 41 of the lid is manufactured using an ink jet method. Prints character information such as numbers. Here, the ink i dropped from the nozzle N onto the printing resin film 9 is an ink having a color different from that of the printing resin film so as to obtain a clear contrast. In this embodiment, white ink (so-called white ink) made of an epoxy resin is used. The printing on the printing resin film may be performed not only by a method of adding ink onto the printing resin film but also by a method of removing a part of the printing resin film using a laser beam.

-Cutting process-
The cutting step is a step of obtaining a plurality of piezoelectric vibrating devices by cutting a region corresponding to the gap 14 with a width narrower than the minimum opening dimension of the gap 14. The area corresponding to the gap 14 is an area between adjacent lid bodies. In the state after the resin film for printing shown in FIG. 7 is cured, the opening dimension represented by the symbol d2 of the gap 14 is the maximum opening dimension, and the opening dimension represented by the symbol d1 is the minimum opening dimension. The distance d2 is the dimension between the most depressed portions of the opposed depressions 13. On the other hand, d1 is the dimension of the narrowest portion between the printing resin films 9 formed on the outer side surface 44 of the facing lid.

  In the cutting process, as shown in FIG. 8, first, a dicing tape (expanding tape) T is attached to the upper surface side of each lid body 4 covered with the insulating resin material of the container base substrate 200. Here, in general, in order to improve the adhesion to an object to be bonded, a process is performed in which pressure is applied while rolling a roller in contact with the upper surface of the dicing tape (the surface not bonded to the lid). However, when the base material of the lid is made of a brittle material such as glass, stress is directly applied to the lid when the roller rolls, which may cause cracks and the like.

  On the other hand, in this embodiment, since the printing resin film 9 is interposed between the lid and the dicing tape, the stress applied when the roller rolls can be reduced. This can prevent the occurrence of cracks and the like.

  Next, only the container mother substrate 200 is cut in the thickness direction by the dicing blade B with a width narrower than the minimum opening dimension d1 of the gap 14. A plurality of crystal resonators 1, 1,..., 1 can be obtained by cutting the container mother substrate 200 and then expanding (stretching) the dicing tape to separate the individual crystal resonators from the tape. (See FIG. 9). In this embodiment, the container mother substrate is cut using a dicing blade, but a beam such as a laser beam or an electron beam may be used. The method for forming the printing resin film on the lid surface is not limited to the method described in this embodiment, and printing is performed on one main surface exposed to the outside of the lid using a tape on which the printing resin film is formed in advance. A method of transferring a resin film for use may be used. In this case, an epoxy resin or a polyimide resin is suitable as a tape material used for the transfer. And as a printing method to the printing resin film formed by the transfer, any method of adding ink onto the printing resin film using an ink jet method or removing a part of the printing resin film using a laser beam Is also applicable.

  In the cutting step, the container mother substrate 200 is cut in a direction from the other main surface side (202) of the container mother substrate toward the one main surface side (201). By cutting in such a direction, the stress during cutting can be reduced. This is because the inclined surface 431 of the lid is a surface inclined inward from the outer surface 44 of the lid, so that a gap is formed between the inclined surface 431 and the container 2, and the printing resin film is formed in the gap. This is because the printing resin film 9 is arranged in a state where it enters and is recessed inward from the outer surface of the lid along the inclined surface 431. That is, by starting cutting from the other main surface side 202 of the container mother substrate 200, the cutting waste at the start of cutting of the dicing blade is swept out into the gap portion, and the cutting waste does not easily stay in the cutting region. As a result, the stress applied during cutting can be reduced, and the container mother substrate can be cut without lowering the cutting efficiency.

Further, since the printing resin film 9 enters the gap between the inclined surface 431 of the lid and the container 2 and the depression 13 is formed inward from the outer surface 44 of the lid along the inclined surface 431, the dicing blade The resin film 9 for printing that has entered the recess 13 functions like a “wedge” during cutting by the above. Thereby, it is possible to prevent the printing resin film 9 from peeling off from the lid surface following the passage of the dicing blade (so-called anchor effect).
The above is the description of the method for manufacturing a crystal resonator according to the present invention.

  According to the manufacturing method, the stress relaxation film 10 is formed on the other main surface 42 facing the one main surface 41 of the lid body in the stress relaxation film forming step. In the resin forming step, the printing resin film 9 is formed on the one main surface 41 exposed to the outside of the lid 4 made of a translucent material. The printing resin film 9 and the stress relaxation film 10 formed in these steps can relieve stress due to expansion and contraction caused by the difference in thermal expansion coefficient. As a result, the occurrence of cracks and the like in the crystal resonator can be suppressed. In addition, when glass or crystal is used as the base material of the lid as a translucent material, the surface of the lid is protected by forming a resin film on one main surface exposed to the outside of the lid. Can do. It also functions as a light shielding film for a light-transmitting lid such as glass or quartz. Furthermore, since a printing resin film is formed on one main surface exposed to the outside of the lid, the resin film can be used as a base layer for printing products.

  According to the manufacturing method, frequency adjustment using a beam can be performed after the bonding step. This is because the lid is made of a translucent material and a beam passage hole is formed in the stress relaxation film 10. That is, the beam passes through the inside of the lid 4, passes through the inside of the passage hole 11 of the stress relaxation film 10, and is irradiated to the frequency adjustment region 30 made of the metal film provided on the crystal vibrating piece 3. By such a manufacturing method, the expansion of the frequency distribution due to the joining of the lid and the container can be suppressed. Further, according to the above manufacturing method, the stress generated by the formation of the printing resin film 9 on one main surface exposed to the outside of the lid in the resin film formation step is the stress formed on the other main surface of the lid. It can be relaxed by the relaxation film 10.

  In the embodiment of the present invention, a surface-mounted crystal resonator is exemplified as a piezoelectric vibration device, but the application of the present invention is not limited to the crystal resonator. For example, as an electronic component element, in addition to a piezoelectric vibrating piece such as a quartz vibrating piece, it is also applicable to a piezoelectric oscillator incorporating an integrated circuit element or a temperature sensitive element, or other piezoelectric vibrating devices used in electronic devices such as a crystal filter. Is possible.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  It can be applied to mass production of piezoelectric vibration devices.

DESCRIPTION OF SYMBOLS 1 Crystal oscillator 2 Container 3 Crystal vibrating piece 4 Cover body 8 Bonding material 9 Printing resin film 10 Stress relaxation film 11 Passing hole 13 Depression 22 Container outer bottom surface 24 Bank part 200 Container mother board 30 Frequency adjustment area 44 Cover body outer surface 41 One main surface of lid body 42 Other main surface of lid body 43 Wall portion 431 Inclined surface (lid body)
44 Outside surface of lid

Claims (5)

A piezoelectric vibration device formed by joining a lid and a container in which at least a piezoelectric vibration piece is accommodated,
A resin film for printing is formed on one main surface exposed to the outside of the lid,
A piezoelectric vibration device characterized in that a stress relaxation film for relaxing stress on the lid is formed on the other principal surface of the lid facing the one principal surface.   The piezoelectric vibration device according to claim 1, wherein the stress relaxation film is a gas adsorption film made of a metal. The lid is made of a translucent material,
The piezoelectric vibrating piece has a frequency adjustment region made of a metal film in which frequency adjustment is performed by irradiation of a beam from the outside of the lid,
3. The piezoelectric vibration device according to claim 1, wherein a passage hole for the beam is formed in a region corresponding to the frequency adjustment region of the stress relaxation film.   In the printing resin film, an opening for passing a beam is formed at a position overlapping the passage hole of the stress relaxation film in plan view, and the opening is filled with the printing resin film. The piezoelectric vibration device according to claim 3. A method for manufacturing a piezoelectric vibration device in which a lid and a container in which at least a piezoelectric vibration piece is accommodated are joined,
A mounting step of mounting a piezoelectric vibrating piece having a frequency adjustment region made of a metal film on which frequency adjustment is performed on a container;
A stress relaxation film forming step of forming a stress relaxation film having a beam passage hole corresponding to the frequency adjustment region on a main surface of the lid made of a light-transmitting material to be bonded to the container;
A joining step for joining the lid and the container;
A frequency adjustment step of adjusting the frequency by irradiating a beam from the outside of the lid, passing through the inside of the lid and the inside of the passage hole, and reducing the metal film in the frequency adjustment region;
A resin film forming step of forming a resin film for printing on one main surface exposed to the outside of the lid;
A printing step of printing on the surface of the printing resin film;
A method of manufacturing a piezoelectric vibration device having

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