Patent Application
20200252049
The present application is based on, and claims priority from JP Application Serial Number 2019-015323, filed Jan. 31, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a resonator device, a manufacturing method for a resonator device, a resonator module, an electronic apparatus, and a vehicle.
A manufacturing method for a quartz crystal resonator is disclosed in JP-A-2014-175853. The manufacturing method includes a step of preparing a base substrate including a plurality of dicing areas, a step of mounting a quartz crystal resonator element in each dicing area, a step of bonding a lid substrate including the same plurality of dicing areas as the base substrate to the base substrate and forming a plurality of resonators at once, and a step of dicing each dicing area. Accordingly, a quartz crystal resonator including a base, a quartz crystal resonator element mounted on the base, and a lid bonded to the base to accommodate the quartz crystal resonator element is obtained. In addition, in the dicing step of JP-A-2014-175853, first, a V-shaped groove that reaches the base substrate from the lid substrate is formed along boundaries of the dicing areas. Next, the dicing is performed by causing fracture from the groove by applying stress.
However, in JP-A-2014-175853, the side surfaces of the base and the lid are planar, and the outer edges of the base and the lid are bonded to each other. Thus, for example, when external stress is applied at the time of falling down or handling of the quartz crystal resonator, stress is likely to be applied to a bonding part, and the strength of the bonding part may be decreased.
A resonator device according to an application example includes abase substrate including a principal surface, a side surface, and an inclined surface that couples the principal surface to the side surface and that is inclined with respect to the principal surface and the side surface, a resonator element arranged on the principal surface side of the base substrate, and a lid that is bonded to the principal surface of the base substrate to accommodate the resonator element between the lid and the base substrate. A bonding area in which the base substrate and the lid are bonded is positioned inside an outer edge of the principal surface.
A manufacturing method for a resonator device according to another application example includes preparing a base wafer that includes a plurality of dicing areas and in which a groove is formed along a boundary between the adjacent dicing areas on a first surface side which is one principal surface, and arranging a resonator element on the first surface side in each dicing area, preparing a lid wafer that includes the plurality of dicing areas and in which a first recess accommodating the resonator element and a second recess which is along the boundary between the adjacent dicing areas and which has a depth greater than a depth of the first recess and an opening width greater than an opening width of the groove are formed on a second surface side which is a principal surface on the base wafer side, and obtaining a device wafer that is a stack of the base wafer and the lid wafer by bonding the first surface to the second surface, and dicing each dicing area by fracturing the base wafer from a tip end of the groove by applying stress to the device wafer.
A resonator module according to another application example includes the resonator device.
An electronic apparatus according to another application example includes the resonator device.
A vehicle according to another application example includes the resonator device.
Hereinafter, a resonator device, a manufacturing method for a resonator device, a resonator module, an electronic apparatus, and a vehicle of the present application example will be described in detail based on embodiments illustrated in the appended drawings.
For example, it is assumed that a resonator device 1 illustrated in
As illustrated in
The base 4 includes a base substrate 41 of a plate shape, an insulating film 42 arranged on the surface of the base substrate 41, and an electrode 43 arranged on the insulating film 42.
The base substrate 41 has a plan view shape of a rectangular plate and includes a lower surface 411 and an upper surface 412 that are in a front-rear relationship to each other, a side surface 413, and an inclined surface 414 that is positioned between the upper surface 412 and the side surface 413 and that couples the upper surface 412 to the side surface 413. The inclined surface 414 has a frame shape surrounding the whole periphery of the upper surface 412. The inner edge of the inclined surface 414 is coupled to the outer edge of the upper surface 412, and the outer edge of the inclined surface 414 is coupled to the upper end of the side surface 413. The side surface 413 is configured as a planar surface that is perpendicular to the upper surface 412. The inclined surface 414 is configured as a planar surface that is inclined with respect to the upper surface 412 and the side surface 413. By disposing the inclined surface 414, a corner C that is formed in a coupling portion between the upper surface 412 and the side surface 413 is cut. Thus, concentration of stress on the corner C is reduced, and the occurrence of a chip or a crack starting from the corner C can be effectively reduced.
In the present embodiment, the inclined surface 414 is formed to surround the whole periphery of the upper surface 412. However, the present embodiment is not for limitation purposes. The inclined surface 414 may be formed to surround a part of the upper surface 412. The inclined surface 414 is configured as a planar surface. However, the inclined surface 414 is not for limitation purposes and may be configured as a curved surface. Furthermore, as a modification example, it may be configured that the base substrate 41 is positioned between the lower surface 411 and the side surface 413 and includes an inclined surface coupling the lower surface 411 to the side surface 413.
As will be described in the manufacturing method described later, the side surface 413 is a fractured surface that is formed by developing a crack by stress. The inclined surface 414 is an etched surface formed by wet etching. By forming the side surface 413 as a fractured surface, the side surface 413 is obtained as a smoother surface. Thus, a chip or a crack is more unlikely to occur in the base substrate 41. In addition, by forming the inclined surface 414 as an etched surface, the inclined surface 414 can be more easily formed.
In addition, the base substrate 41 includes two through holes 415 and 416 that pass through the upper surface 412 and the lower surface 411.
The base substrate 41 is a semiconductor substrate. The semiconductor substrate is not particularly limited. For example, a silicon substrate, a germanium substrate, or a compound semiconductor substrate of GaP, GaAs, InP, or the like can be used. By using the semiconductor substrate as the base substrate 41, the base 4 can be formed using a semiconductor process. Thus, the size of the resonator device 1 can be reduced. In addition, as will be described later in other embodiments, a semiconductor circuit can be formed in the base 4, and the base 4 can be effectively used. Particularly, in the present embodiment, a single crystal silicon substrate of which the upper surface 412 is a (100) crystal surface is used as the base substrate 41. Accordingly, the base substrate 41 is inexpensive and is easily obtained. The base substrate 41 is not limited to the semiconductor substrate. For example, a ceramic substrate or a glass substrate can be used.
When the single crystal silicon substrate of which the upper surface 412 is the (100) crystal surface is used as the base substrate 41, a (111) crystal surface or a (101) crystal surface is exposed by performing wet etching on the base substrate 41. Thus, the inclined surface 414 can be easily formed using the crystal surface. That is, by forming the upper surface 412 as the (100) crystal surface and forming the inclined surface 414 as the (111) crystal surface or the (101) crystal surface, the base substrate 41 including the inclined surface 414 can be more simply formed. The inclination angle of the inclined surface 414 with respect to the upper surface 412 is not particularly limited. For example, the inclination angle is approximately greater than or equal to 30° and less than or equal to 60°.
The insulating film 42 is arranged on the surface of the base substrate 41. However, the insulating film 42 is not formed in a bonding area Q between the base substrate 41 and the lid 3 on the upper surface 412 of the base substrate 41. That is, in the bonding area Q, silicon constituting the upper surface 412 is exposed from the insulating film 42. The insulating film 42 is not particularly limited. In the present embodiment, a silicon oxide film (SiO2 film) is used. A forming method for the insulating film 42 is not particularly limited. For example, the insulating film 42 may be formed by subjecting the surface of the base substrate 41 to thermal oxidation, or may be formed by plasma CVD using tetraethoxysilane (TEOS).
The electrode 43 is arranged on the insulating film 42. The electrode 43 includes a first interconnect 44 and a second interconnect 45 that are insulated by the insulating film 42. The first interconnect 44 includes an internal terminal 441 positioned on the upper surface 412 side, that is, inside the accommodation space S, an external terminal 442 positioned on the lower surface 411 side, that is, outside the accommodation space S, and a through electrode 443 that is formed in the through hole 415 and that electrically couples the internal terminal 441 to the external terminal 442. Similarly, the second interconnect 45 includes an internal terminal 451 positioned on the upper surface 412 side, an external terminal 452 positioned on the lower surface 411 side, and a through electrode 453 that is formed in the through hole 416 and that electrically couples the internal terminal 451 to the external terminal 452. In addition, the electrode 43 includes two dummy electrodes 461 and 462 arranged on the lower surface 411 side.
The lid 3 has a box shape and includes the bottomed recess 32 that is open on a lower surface 31. As illustrated in
The lid 3 is a semiconductor substrate. The semiconductor substrate is not particularly limited. For example, a silicon substrate, a germanium substrate, or a compound semiconductor substrate of GaP, GaAs, InP, or the like can be used. By using the semiconductor substrate as the lid 3, the lid 3 can be formed using a semiconductor process. Thus, the size of the resonator device 1 can be reduced. Particularly, in the present embodiment, a single crystal silicon substrate in which the lower surface 31 is the (100) crystal surface is used as the lid 3. Accordingly, the lid 3 is inexpensive and is easily obtained. In addition, the materials of the base substrate 41 and the lid 3 can be matched, and a difference in coefficient of thermal expansion between the materials can be substantially equal to zero. Thus, the occurrence of thermal stress caused by thermal expansion is reduced, and the resonator device 1 has excellent resonance characteristics.
The lid 3 is not limited to the semiconductor substrate. For example, a ceramic substrate or a glass substrate can be used. A type of substrate different from the base substrate 41 may be used as the lid 3. Particularly, when the glass substrate having light-transmitting characteristics is used as the lid 3, a part of an excitation electrode 521 can be removed by irradiating the resonator element 5 with a laser through the lid 3 after the manufacturing of the resonator device 1, and the frequency of the resonator element 5 can be adjusted.
The lid 3 is directly bonded to the upper surface 412 of the base substrate 41 through a bonding member 6 on the lower surface 31. In the present embodiment, the lid 3 and the base substrate 41 are bonded using diffusion bonding that uses diffusion between metals among types of direct bonding. Specifically, as illustrated in
In the present embodiment, diffusion bonding is applied using the bonding member 6. Alternatively, the base substrate 41 and the lid 3 may be directly bonded without the bonding member 6. In this case, the single crystal silicon substrate can be applied as the base substrate 41, and the single crystal silicon substrate can be applied as the lid 3. As method of direct bonding without using the bonding member 6, for example, the surface of the bonding part between the base substrate 41 and the lid 3 is activated by irradiating the bonding part with inert gas such as Ar, and the activated parts are bonded to each other.
For example, the metal film 61 is configured by forming a plated layer 612 that is a stack of nickel (Ni)/palladium (Pd)/gold (Au) on a base portion 611 formed of copper (Cu). Similarly, the metal film 62 is configured by forming a plated layer 622 that is a stack of Ni/Pd/Au on a base portion 621 formed of Cu. Alternatively, the metal films 61 and 62 may be configured to include a ground layer that is a thin film of chrome or titanium, and a thin film of gold formed above the ground layer by sputtering. The layers of gold on the surfaces of the metal films 61 and 62 are diffusion-bonded. According to the diffusion bonding, the lid 3 and the base substrate 41 can be bonded at room temperature (a temperature lower than the melting points of the metal films 61 and 62). Thus, internal stress is unlikely to remain in the package 2, and thermal damage to the resonator element 5 is reduced.
The bonding area Q between the base substrate 41 and the lid 3 is positioned inside the outer edge 412a of the upper surface 412 in plan view. That is, a gap G is formed between the bonding area Q and the outer edge 412a. By arranging the bonding area Q at a position away from the outer edge 412a without an overlap between the bonding area Q and the outer edge 412a, external stress is unlikely to be applied to the bonding area Q. As a specific example, for example, when the resonator device 1 hits the ground by falling down, the bonding area Q does not directly come into contact with the ground. Thus, the bonding area Q does not directly receive impact caused by falling down. Accordingly, excessive stress is unlikely to be applied to the bonding area Q, and a decrease in strength or breakage of the bonding area Q can be effectively reduced.
The gap G is not particularly limited. For example, as described above, when the size of the resonator device 1 is approximately length L×width W=1.2 mm×1.0 mm, the gap G can be approximately greater than or equal to 0.01 mm and less than or equal to 0.05 mm. In the present embodiment, the whole area of the bonding area Q is positioned inside the outer edge 412a. However, the present embodiment is not for limitation purposes. A part of the bonding area Q may overlap with the outer edge 412a. In this case, the area in overlap with the outer edge 412a may be less than or equal to 30%, more desirably less than or equal to 20%, and further desirably less than or equal to 10% of the whole area.
As illustrated in
The electrode 52 includes the excitation electrode 521 arranged on the upper surface of the resonator substrate 51 and an excitation electrode 522 arranged on the lower surface of the resonator substrate 51 in opposition to the excitation electrode 521 through the resonator substrate 51. In addition, the electrode 52 includes a pair of terminals 523 and 524 arranged on the lower surface of the resonator substrate 51, an interconnect 525 electrically coupling the terminal 523 to the excitation electrode 521, and an interconnect 526 electrically coupling the terminal 524 to the excitation electrode 522.
The configuration of the resonator element 5 is not limited to the above configuration. For example, the resonator element 5 may be of a mesa type in which a resonance area interposed between the excitation electrodes 521 and 522 protrudes from the surrounding area of the resonance area. Conversely, the resonator element 5 may be of an inverted mesa type in which the resonance area recessed from the surrounding area of the resonance area. In addition, a bevel process of grinding the surrounding area of the resonator substrate 51, or a convex process of forming the upper surface and the lower surface of the resonator substrate 51 into convex surfaces may be performed.
The resonator element 5 that resonates in the thickness shear resonance mode is not for limitation purposes. For example, the resonator element 5 may be a tuning fork type resonator element of which two vibrating arms are subjected to tuning fork resonance in an in-plane direction. That is, the resonator substrate 51 is not limited to the AT cut quartz crystal substrate and may be a quartz crystal substrate other than the AT cut quartz crystal substrate such as an X cut quartz crystal substrate, a Y cut quartz crystal substrate, a Z cut quartz crystal substrate, a BT cut quartz crystal substrate, an SC cut quartz crystal substrate, or an ST cut quartz crystal substrate. In the present embodiment, the resonator substrate is formed of quartz crystal. However, the present embodiment is not for limitation purposes. For example, the resonator substrate 51 may be formed of a piezoelectric single crystal such as lithium niobate, lithium tantalate, lithium tetraborate, langasite, potassium niobate, or gallium phosphate, or may be formed of other piezoelectric single crystals. Furthermore, the resonator element 5 is not limited to the piezoelectric drive type resonator element and may be an electrostatic drive type resonator element that uses electrostatic force.
As illustrated in
The conductive bonding members B1 and B2 are not particularly limited as long as the conductive bonding members B1 and B2 have both conductivity and bondability. For example, various metal bumps such as a gold bump, a silver bump, a copper bump, and a solder bump, and conductive adhesives obtained by dispersing a conductive filler such as a silver filler into various polyimide-based, epoxy-based, silicone-based, and acrylic-based adhesives can be used. When the former metal bumps are used as the conductive bonding members B1 and B2, the occurrence of gas from the conductive bonding members B1 and B2 can be reduced, and an environmental change in the accommodation space S, particularly, an increase in pressure, can be effectively reduced. Meanwhile, when the latter conductive adhesives are used as the conductive bonding members B1 and B2, the conductive bonding members B1 and B2 are softer than the metal bumps, and stress is unlikely to occur in the resonator element 5.
The resonator device 1 is described thus far. As described above, the resonator device 1 includes the base substrate 41 that includes the upper surface 412 which is the principal surface, the side surface 413, and the inclined surface 414 which couples the upper surface 412 to the side surface 413 and that is inclined with respect to the upper surface 412 and the side surface 413, the resonator element 5 that is arranged on the upper surface 412 side of the base substrate 41, and the lid 3 that is a cover bonded to the upper surface 412 of the base substrate 41 such that the resonator element 5 is accommodated between the lid 3 and the base substrate 41. The bonding area Q between the base substrate 41 and the lid 3 is positioned inside the outer edge 412a of the upper surface 412. By disposing the inclined surface 414 in the base substrate 41, the corner C between the upper surface 412 and the side surface 413 is cut. Thus, concentration of stress on the corner C is reduced, and the occurrence of a chip or a crack starting from the corner C can be effectively reduced. Furthermore, since the bonding area Q between the base substrate 41 and the lid 3 is positioned inside the outer edge 412a of the upper surface 412, the bonding area Q is unlikely to directly receive external force. Accordingly, excessive stress is unlikely to be applied to the bonding area Q, and a decrease in strength or breakage of the bonding area Q can be effectively reduced. Thus, the resonator device 1 having excellent mechanical strength is obtained.
As described above, the base substrate 41 is the single crystal silicon substrate. The upper surface 412 is the (100) crystal surface. Accordingly, the base substrate 41 can be inexpensively formed with excellent processing accuracy. In addition, the inclined surface 414 can be easily formed by wet etching.
As described above, the side surface 413 is a fractured surface. Accordingly, the side surface 413 is obtained as a smoother surface. Thus, parts on which stress is concentrated are reduced, and a chip or a crack is more unlikely to occur in the base substrate 41.
As described above, the base substrate 41 and the lid 3 are directly bonded. Accordingly, the base substrate 41 and the lid 3 can be more firmly bonded. In addition, bonding can be performed at room temperature. Thus, the resonator device 1 in which residual stress is sufficiently reduced can be manufactured.
As described above, the side surface 38 of the lid 3 includes at least one corner 39, and the corner 39 is rounded. Accordingly, concentration of stress on the corner 39 is reduced, and the occurrence of a chip of the lid 3 or a crack in the lid 3 can be effectively reduced. Thus, the resonator device 1 having excellent mechanical strength is obtained.
Next, a manufacturing method for the resonator device 1 will be described. As illustrated in
First, as illustrated in
Next, as illustrated in
Next, as illustrated in
First, as illustrated in
Next, the metal film 62 is formed on the upper surface 412 of each base substrate 41, and the metal film 61 is formed on the lower surface 31 of each lid 3. Next, for example, the metal films 61 and 62 are activated by blowing Ar gas to the metal films 61 and 62. As illustrated in
Next, as illustrated in
As illustrated in
The manufacturing method for the resonator device 1 is described thus far. The manufacturing method for the resonator device 1 includes a step of preparing the base wafer 400 that includes the plurality of dicing areas R and in which the groove SW12 is formed along the boundary between the adjacent dicing areas Ron the upper surface 401 side as a first surface which is one principal surface, and arranging the resonator element 5 on the upper surface 401 side in each dicing area R, a step of preparing the lid wafer 300 that includes the plurality of dicing areas R and in which the recess 32 which is a first recess accommodating the resonator element 5 and the recess SW21 which is a second recess along the boundary between the adjacent dicing areas R and which has the depth D1 greater than the depth D2 of the recess 32 and the opening width W2 greater than the opening width W1 of the groove SW12 are formed on the lower surface 301 side as a second surface which is the principal surface on the base wafer 400 side, and obtaining the device wafer 100 that is a stack of the base wafer 400 and the lid wafer 300 by bonding the upper surface 401 to the lower surface 301, and a step of dicing each dicing area R by fracturing the base wafer 400 from the tip end of the groove SW12 by applying stress to the device wafer 100.
According to the manufacturing method, a plurality of resonator devices 1 having high mechanical strength can be manufactured at the same time. Particularly, in the dicing step, the apex of the groove SW12 as a starting point of fracture is sufficiently separated from the bonding area Q. Thus, excessive stress is unlikely to be applied to the bonding area Q, and a decrease in strength of the bonding area Q or breakage of the bonding area Q at the time of manufacturing can be reduced.
In the present embodiment, in the step of preparing the base wafer 400, the groove SW12 forms a groove that is tapered in sectional view. By using this configuration, the base wafer 400 can be easily fractured from the tip end of the groove SW12 in the dicing step.
The resonator device 1 according to the present embodiment is the same as the resonator device 1 of the first embodiment except that an oscillation circuit 48 is formed in the base 4. In the following description, differences between the resonator device 1 of the second embodiment and the resonator device 1 of the first embodiment will be mainly described, and the same matters will not be described. In
In the resonator device 1 of the present embodiment, as illustrated in
According to the second embodiment, the same effect as the first embodiment can be exhibited. In the present embodiment, the lower surface 411 of the base substrate 41 is set as the active surface. However, the present embodiment is not for limitation purposes. The upper surface 412 of the base substrate 41 may be set as the active surface. By setting the upper surface 412 of the base substrate 41 as the active surface, the resonator device and the oscillation circuit 48 can be electrically coupled at a low impedance. Thus, oscillation of the oscillation circuit 48 can be stabilized.
A resonator module 1000 illustrated in
For example, the support substrate 1010 is an interposer substrate. A plurality of coupling terminals 1011 are arranged on the upper surface of the support substrate 1010. A plurality of mount terminals 1012 are arranged on the lower surface of the support substrate 1010. An internal interconnect, not illustrated, is arranged in the support substrate 1010. Each coupling terminal 1011 is electrically coupled to the corresponding mount terminal 1012 through the internal interconnect. The support substrate 1010 is not particularly limited. For example, a silicon substrate, a ceramic substrate, a resin substrate, a glass substrate, or a glass epoxy substrate can be used.
The circuit substrate 1020 is bonded to the upper surface of the support substrate 1010 through a die attaching material. In the circuit substrate 1020, an oscillation circuit 1023 that generates the frequency of a reference signal such as a clock signal by oscillating the resonator element 5 of the resonator device 1 is formed. A plurality of terminals 1022 electrically coupled to the oscillation circuit are arranged on the upper surface of the oscillation circuit 1023. A part of the terminals 1022 is electrically coupled to the coupling terminals 1011 through bonding wires BW. A part of the terminals 1022 are electrically coupled to the resonator device 1 through a conductive bonding member B3 such as solder.
The mold material M molds the circuit substrate 1020 and the resonator device 1 and protects the circuit substrate 1020 and the resonator device 1 from moisture, dust, shock, and the like. The mold material M is not particularly limited. For example, a thermosetting type epoxy resin can be used, and the molding can be performed using a transfer molding method.
The resonator module 1000 includes the resonator device 1. Thus, the effect of the resonator device 1 can be accomplished, and excellent reliability can be exhibited. Particularly, as described above, in the resonator device 1, the corners 39 of the side surface 38 of the lid 3 are rounded. Thus, the mold material M easily flows around the lid 3 during the molding. Thus, voids are unlikely to occur during the molding, and the resonator device 1 and the circuit substrate 1020 can be more securely protected from moisture and the like.
The electronic apparatus including the resonator device according to the present disclosure is applied to a laptop type personal computer 1100 illustrated in
The personal computer 1100 as the electronic apparatus includes the resonator device 1. Thus, the effect of the resonator device 1 can be accomplished, and high reliability can be exhibited.
The electronic apparatus including the resonator device according to the present disclosure is applied to a mobile phone 1200 illustrated in
The mobile phone 1200 as the electronic apparatus includes the resonator device 1. Thus, the effect of the resonator device 1 can be accomplished, and high reliability can be exhibited.
The electronic apparatus including the resonator device according to the present disclosure is applied to a digital still camera 1300 illustrated in
The digital still camera 1300 as the electronic apparatus includes the resonator device 1. Thus, the effect of the resonator device 1 can be accomplished, and high reliability can be exhibited.
In addition to the personal computer, the mobile phone, and the digital still camera, for example, the electronic apparatus according to the present disclosure can be applied to a smartphone, a tablet terminal, a timepiece (including a smart watch), an ink jet type ejecting apparatus (for example, an ink jet printer), a laptop type personal computer, a television, a wearable terminal such as a head-mounted display (HMD), a video camera, a video tape recorder, a car navigation apparatus, a pager, an electronic organizer (including an electronic organizer having a communication function), an electronic dictionary, an electronic calculator, an electronic game apparatus, a word processor, a workstation, a videophone, a security television monitor, an electronic binocular, a POS terminal, a medical apparatus (for example, an electronic thermometer, a blood pressure meter, a blood glucose meter, an electrocardiograph, an ultrasound diagnosis apparatus, and an electronic endoscope), a fishfinder, various measuring apparatuses, a mobile terminal base station apparatus, meters (for examples, meters of a vehicle, an aircraft, and a ship), a flight simulator, a network server, and the like.
An automobile 1500 illustrated in
The automobile 1500 as the vehicle includes the resonator device 1. Thus, the effect of the resonator device 1 can be accomplished, and high reliability can be exhibited.
The vehicle is not limited to the automobile 1500 and can be applied to an airplane, a ship, an automatic guided vehicle (AGV), a biped robot, an unmanned airplane such as a drone, and the like.
While the resonator device, the manufacturing method for the resonator device, the resonator module, the electronic apparatus, and the vehicle of the present application example are described thus far based on the illustrated embodiments, the present disclosure is not limited to the embodiments. The configuration of each unit can be replaced with any configuration having the same function. Any other constituents may be added to the present disclosure. The present disclosure may be a combination of any two or more configurations in each of the embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-015323 | Jan 2019 | JP | national |
