JP4721101B2 - Piezoelectric device, method for manufacturing piezoelectric device, and electronic apparatus - Google Patents

Description

The present invention method for manufacturing a piezoelectric device and piezoelectric device, and the relates to an electronic device equipped with the piezoelectric device, particularly suitable piezoelectric device and a method of manufacturing the compact and thin, and an electronic apparatus.

Conventionally, as a surface acoustic wave (SAW) device (piezoelectric device) such as a surface acoustic wave oscillator, a SAW element piece inside a package and an integrated circuit (IC: Integrated) for controlling oscillation of the SAW element piece Circuit) is known.

What is considered as a problem in the piezoelectric device having such a configuration is broadly divided into reducing the size and thickness of the SAW device and removing the influence of heat and stress on the SAW element piece mounted in the package. Can be mentioned. Both of these often have conflicting effects in manufacturing, and it is difficult to realize both at the same time.

For example, the technique disclosed in Patent Document 1 can be cited as a technique that is considered to be very effective in reducing the size and thickness of a piezoelectric device . The piezoelectric device manufactured by the technique disclosed in Patent Document 1 has a configuration in which a SAW element piece and an IC are vertically stacked and mounted on a package. The specific configuration is as follows. First, the IC is flip-chip bonded to an electrode pad formed on the bottom of a package base constituting the package. As a result, the active surface of the IC faces the bottom of the package base, and the non-active surface is exposed to the upper opening side of the package base. Next, a SAW element piece is mounted with an adhesive on the inactive surface of the IC exposed to the upper opening side. With this configuration, the active surface (electrode formation surface) of the SAW element piece is exposed to the upper opening side of the package base. Then, the SAW element piece is mounted by wire bonding the electrode of the SAW element piece exposed to the upper opening side and the electrode pad formed on the package base. Piezoelectric devices manufactured in this way can reduce the gap between the IC and SAW element pieces, reduce the dead space in the thickness direction (longitudinal direction) that occurs in the package, and achieve a reduction in thickness. can do. Further, since the IC and the SAW element piece are stacked in the vertical direction, the mounting area of the package itself can be reduced.

On the other hand, as a technique for avoiding the influence of heat on the SAW element piece, there is a technique disclosed in Patent Document 2, for example. The technique disclosed in Patent Document 2 is a countermeasure against the fact that the SAW element piece is easily affected by heat due to the package constituent member that is thinned as the piezoelectric device becomes smaller and thinner. This is a piezoelectric device in which the element piece has a cantilever structure and a support is provided on the support portion when cantilevered. According to such a configuration, since the installation area for the package is reduced, the probability that an external force such as heat or impact applied to the package propagates to the SAW element piece is reduced. Moreover, since the base is provided in the support portion, this portion is not easily affected by external force.
JP 2005-57577 A JP 2003-298388 A

It can be said that the technique disclosed in Patent Document 1 is effective for reducing the size and thickness of a piezoelectric device . However, according to the above configuration, the weight of the IC and the weight of the SAW element piece are supported by the electrode pads formed on the active surface of the IC. When the SAW element piece is mounted on the package base, wire bonding is used. Therefore, an impact generated when the wire is connected may be a burden on the IC.

In addition, when applying the technique described in Patent Document 2, it is necessary to provide a part to be a base of the SAW element piece as a package structure. Therefore, there are many restrictions on the package structure, and the piezoelectric device itself is reduced in size and size. It becomes difficult to reduce the thickness.

In the present invention, the piezoelectric device is suitable for downsizing and thinning, suppresses the propagation of stress to the SAW element piece, and does not apply a physical load to the IC even when the IC is mounted. and to provide a specific manufacturing method for manufacture of piezoelectric devices and the piezoelectric device. Another object of the present invention is to provide an electronic apparatus equipped with the piezoelectric device having the above-described configuration.

In order to achieve the above object, avoid mounting the surface acoustic wave element piece directly on the package. When mounting an integrated circuit, the integrated circuit and the surface acoustic wave element piece are stacked vertically. It is considered that it is only necessary to arrange the integrated circuit and the surface acoustic wave element so as not to contact each other. Therefore, the piezoelectric device according to the present invention is a piezoelectric device that implements the surface acoustic wave element in a package base, a substrate formed with the openings in the plate surface, to the substrate, exciting the opening A surface acoustic wave element piece mounted with the electrodes facing each other, and the substrate is disposed inside the package base such that the excitation electrode formed on the surface acoustic wave element piece faces the upper opening side of the package base. arranged, the surface acoustic wave element is characterized in that a configuration in which the lead was convexly in the opening Ru is supported on the substrate.

With such a configuration, since the structure of mounting the surface acoustic wave element via the substrate against the package, an external force such as stress or heat from the outside to be added to the package, the surface acoustic wave It does not propagate directly to the element piece. In addition, the piezoelectric device can be reduced in size and thickness. Also, an opening is provided in the substrate on which the surface acoustic wave element piece is mounted, and the excitation electrode formed on the surface acoustic wave element piece is opposed to the opening. By arranging so as to face the opening side, frequency adjustment can be performed after the surface acoustic wave element piece is mounted on the package.

The piezoelectric device according to the present invention, an electronic component is mounted on the bottom of the package base, a piezoelectric device that implements upper surface acoustic wave element of the electronic component, subjected to the upper space of the electronic component passed, comprising a substrate formed with the openings in the plate surface, the surface acoustic wave element is mounted on the substrate in a state that the excitation electrode is opposed to the opening, wherein the excitation electrode package base of the upper opening It is disposed such that the section side may be characterized in that it has a structure which is supported by a lead that is convexly into the opening.

With such a configuration, the surface acoustic wave element piece is suspended in the cavity of the package base via the substrate . For this reason, external forces such as stress and heat applied to the package do not directly propagate to the surface acoustic wave element piece. In addition, a configuration is realized in which the integrated circuit and the surface acoustic wave element piece are stacked in the vertical direction, and no partition wall is provided inside the package, and the two are not in direct contact with each other. For this reason, the piezoelectric device is reduced in size and thickness, and an extra load is not applied to the integrated circuit when the oscillation module is configured. Therefore, a highly reliable product can be provided as a piezoelectric device . Also, an opening is provided in the substrate on which the surface acoustic wave element piece is mounted, and the excitation electrode formed on the surface acoustic wave element piece is opposed to the opening. By arranging so as to face the opening side, frequency adjustment can be performed after the surface acoustic wave element piece is mounted on the package.

The piezoelectric device according to the present invention includes a package base having a cavity, a lid for sealing the opening of the package base, an element piece having a piezoelectric member formed with an excitation electrode and a lead electrode, An insulating substrate having a lead and an opening, and an electronic component, wherein the element piece is mounted on the substrate so as to electrically connect the lead and the lead electrode, and is formed at the bottom of the cavity. The electronic component is mounted, the substrate is mounted on the package base so as to be in a state of being spanned between side walls in the cavity, and the leads and electrode pads formed on the package base are electrically connected. , said the package base and the element piece and a non-contact state, to expose the excitation electrode from the the opening package base of the opening of the substrate It may also be characterized in.

Even with such a piezoelectric device, the piezoelectric device can be reduced in size and thickness. Further, the propagation of stress to the element piece can be suppressed, and even when the IC is mounted as an electronic component, it is possible to eliminate the physical load on the IC. In addition, an opening is provided in the substrate on which the element piece is mounted, the opening is opposed to the excitation electrode formed on the element piece, and the excitation electrode is exposed from the opening of the substrate and the opening of the package base. The frequency adjustment can be performed after the element piece is mounted on the package.

Further, in the piezoelectric device having the above-described characteristics, the element piece may be disposed above the electronic component.

In the piezoelectric device having the above-described characteristics, the substrate may be connected and fixed to the package base on each side of the side wall.

In the piezoelectric device having the above-described configuration, the integrated circuit is preferably mounted by flip chip bonding.
With such a configuration, it is not necessary to secure a space for performing wire bonding as a cavity. For this reason, it is possible to reduce the height of the piezoelectric device .

The electronic device mentioned in the above problem is characterized by mounting a piezoelectric device having the above-described configuration. By mounting the piezoelectric device having the above-described configuration, the electronic apparatus can be reduced in size and thickness and can be highly reliable.

Moreover, in manufacturing the piezoelectric device of the above configuration, the light-transmitting material employed in the lid sealing the package base of the opening, the thickness of the excitation electrodes after sealing the package base It is better to adjust the frequency.

  By adopting such a manufacturing method, the variation in the oscillation frequency caused by the influence of the stress generated when the surface acoustic wave element piece is mounted and the gas generated when the package base is sealed is reduced. It becomes possible to adjust after base sealing.

Hereinafter, a piezoelectric device of the present invention and an electronic apparatus equipped with the same will be described with reference to the drawings. In addition, embodiment shown below shows a part of suitable form on implementing this invention, and this invention is not restrained only by the following form.

First, a first embodiment according to a piezoelectric device (specifically, a surface acoustic wave (SAW) device ) of the present invention will be described with reference to FIG. 1A is a side sectional view of a SAW device, and FIG. 1B is a plan view of the SAW device. The SAW device 10 of this embodiment has a basic configuration of a SAW element piece 12 and a package 14 in which the SAW element piece 12 is mounted.

  In the basic constituent member as described above, the package 14 includes a package base (base) 16 having a cavity 16a for housing the SAW element piece 12, and a lid 18 for sealing the upper opening of the cavity 16a. . In the package 14 of this embodiment, the base 16 and the lid 18 are joined by seam welding via the seal ring 20. The base 16 may be formed by sintering a ceramic material such as alumina, and a metal (for example, kovar) or glass having a thermal expansion coefficient close to that of the base 16 may be used for the lid 18. As the seal ring 20, it is preferable to use a material having a thermal expansion coefficient close to that of the constituent members of the base 16 and the lid 18, and when the base 16 and the lid 18 are constituted by the above-described members, Kovar is preferably used. . The base 16 is usually formed by laminating a plurality of substrates and sintering the substrates.

The SAW element piece 12 is obtained by arranging an electrode pattern 12a formed of an electrode member such as aluminum on a piezoelectric member such as quartz (SiO ₂ ), lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ), or the like. . Examples of the electrode pattern 12a formed on the plate surface of the piezoelectric member include an interdigital transducer (IDT) and a grating reflector (reflector). The SAW element 12 of this embodiment is mounted on the base 16 via a TAB (Tape Automated Bonding) substrate 22. The TAB substrate 22 is obtained by arranging leads (specific shapes are not shown) formed by copper plating or the like on a film made of a resin such as polyimide. As shown in FIG. 2, the TAB substrate 22 employed in the present embodiment has an opening (device hole) 22a on the plate surface. The SAW element piece 12 shown in FIG. 3 is mounted by connecting a lead electrode to a lead (inner lead) 24 protruding from the opening 22 a of the TAB substrate 22. At this time, the excitation electrode (electrode pattern) 12 a formed on the SAW element piece 12 is opposed to the opening 22 a formed on the plate surface of the TAB substrate 22.

  The TAB substrate 22 on which the SAW element piece 12 is mounted as described above is mounted on a mounting portion (electrode pad) 26 disposed in the base 16. When mounting the TAB substrate 22, the excitation electrode 12a of the SAW element piece 12 is disposed so as to face the upper opening side of the cavity 16a. With this configuration, the excitation electrode 12a is exposed to the outside in a state where the SAW element piece 12 is mounted, and frequency adjustment in this state is possible. The frequency may be adjusted by removing a part of the excitation electrode 12a with a laser or the like and adjusting the thickness.

  In addition, the SAW element piece 12 is supported by the leads 24 so that the bottom portion of the base 16 and the SAW element piece 12 are in a non-contact state with the TAB substrate 22 mounted on the base 16. With such a configuration, external forces such as heat, impact, and stress applied to the base 16 are buffered or absorbed by the TAB substrate 22 and do not directly propagate to the SAW element piece 12. For this reason, fluctuations in the oscillation frequency caused by stress or the like can be reduced.

Further, unlike the configuration in which the bottom portion of the base 16 is thickened to prevent generation of stress and heat propagation, a TAB substrate 22 that can be formed thin is spanned between the side walls of the base 16, and the SAW element piece 12 is placed in the cavity 16a. The external force is prevented from directly propagating to the SAW element piece 12 by being supported in a suspended state. For this reason, it is possible to prevent the external force from propagating to the SAW element piece 12 mounted inside, while making the package 14 thin. According to the SAW device 10 adopting such a configuration, even when a SAW element piece that is easily influenced by the influence of external stress is adopted, it is possible to suppress the variation in apex temperature.
When a glass lid is employed as the lid 18, the frequency of the SAW element piece 12 can be adjusted after the base 16 (cavity 16 a) is sealed.

  Next, with reference to FIG. 4, the manufacturing process of the SAW device 10 according to the present embodiment will be described. First, the base 16 is formed. The formation of the base 16 is not limited to the above-described ceramic sintering (S100). Next, the SAW element piece 12 is mounted on the TAB substrate 22 simultaneously with the formation of the base 16 or before and after the formation of the base 16 (S110). Thereafter, the TAB substrate 22 on which the SAW element pieces 12 are mounted is mounted in the base 16 (S120). After mounting the TAB substrate 22, the base 16 and the lid 18 are joined via the seal ring 20 to seal the upper opening of the cavity 16a (S130). When a glass lid is used as the lid 18, the frequency of the SAW element piece 12 is adjusted using a laser or the like after the step S130. According to such a manufacturing process, the SAW element piece 10 can be mounted on the TAB substrate 22 and the base 16 can be formed at the same time. Therefore, the SAW device 10 can be manufactured with the same cycle time and throughput as conventional. can do. In addition, when the frequency adjustment of the SAW element piece 12 is performed after sealing, it is possible to provide a highly accurate SAW device 10 with suppressed frequency variation.

  Next, a second embodiment according to the SAW device of the present invention will be described with reference to FIG. 5A is a cross-sectional view of the SAW device, and FIG. 5B is a plan view of the SAW device. The SAW device according to the present embodiment basically includes a SAW element piece, an integrated circuit (IC) that controls the oscillation frequency of the SAW element piece, and a package that accommodates the SAW element piece and the IC therein. And

  Since the SAW device according to the present embodiment includes components having the same functions as those of the SAW device according to the first embodiment described above, components having the same functions are denoted by reference numerals obtained by adding 100 to the reference numerals in the drawings. The detailed description is omitted.

  The configuration of the package 114 of this embodiment is almost the same as the configuration of the package 14 in the SAW device 10 in the first embodiment described above, but the cavity 116a of the base 116 is widened to accommodate the IC 128. This is different from the package 14 in the first embodiment.

  In the base 116 of the present embodiment, the lower region of the cavity 116a is used as a storage region for the IC 128, and the upper region of the cavity 116a is used as a storage region for the SAW element piece 112. In the present embodiment, the IC 128 is mounted in the lower region of the cavity 116a with the active surface facing upward via the adhesive 130 or the like. An electrode pad (not shown) formed on the active surface facing upward is electrically connected to an electrode pad (not shown) formed on the base 116 by a bonding wire 132.

  As in the first embodiment, the SAW element piece 112 is mounted on the TAB substrate 122 as a pre-process to be mounted on the base 116. In this embodiment, the TAB substrate 122 on which the SAW element piece 112 is mounted is mounted on the upper region of the cavity 116a. The TAB substrate 122 is mounted by passing the TAB substrate 122 between the side walls of the package 114, and a lead formed on the TAB substrate 122 and an electrode pad (mounting part) 126 formed on the side wall across the TAB substrate 122. This is done by electrical connection. In the mounted state, the excitation electrode 12a of the SAW element piece 12 is arranged to face the opening side of the cavity 116a, as in the first embodiment. Then, the SAW element piece 112 is supported by the leads 124 so that the bonding wire 132 for mounting the IC 128 and the non-active surface of the SAW element piece 112 do not contact each other.

  With such a configuration, the SAW element piece 112 is disposed (suspended) in the cavity via the TAB substrate 122, so that the shock and heat applied to the package 114 are affected by the SAW element piece 112. No longer propagates directly to Since the SAW element piece 112 and the IC 128 are arranged in the height direction, the SAW device 110 including the IC 128 can be downsized. Also, the SAW element piece 112 is arranged on the top of the IC 128, but unlike the conventional technique, the direct contact between the two is eliminated, so that the IC 128 is damaged during mounting (during module configuration). There is no fear. Therefore, according to the SAW device 110 having the above-described configuration, the SAW device 110 can be reduced in size and thickness, and the highly reliable SAW device 110 that does not apply an extra load to the IC 128 can be obtained. Other functions and effects are the same as those of the SAW device 10 shown in the first embodiment.

  Next, the manufacturing process of the SAW device 110 of this embodiment will be described with reference to FIG. First, the base 116 is formed (S200). Next, the IC 128 is mounted on the bottom of the cavity 116a of the formed base 116 (S220). The SAW element piece 112 is mounted on the TAB substrate 122 simultaneously with or before or after the formation process of the base 116 or the IC 128 mounting process (S210). After the IC 128 is mounted on the base 116 and the SAW element piece 112 is mounted on the TAB substrate 122, the TAB substrate 122 is mounted on the base 116 (S230). In this embodiment, the mounting is performed so that the TAB substrate 122 is stretched between the side walls of the base 116. After the TAB substrate 122 is mounted on the base 116, the base 116 and the lid 118 are joined, and the upper opening of the cavity 116a is sealed (S240). According to such a manufacturing process, since the process of mounting the SAW element piece 112 on the TAB substrate 122 can be performed simultaneously with the process of forming the base 116 or the process of mounting the IC 128 on the base 116, the cycle time is the same as the conventional cycle time. The SAW device 110 can be manufactured with a high throughput.

Next, a third embodiment of the surface acoustic wave device according to the present invention will be described with reference to FIG.
The basic configuration of the SAW device of this embodiment is the same as that of the SAW device 110 in the second embodiment described above. Therefore, the same reference numerals are given to the portions having the same functions, and the detailed description thereof is omitted.

The SAW device 110 according to the present embodiment is characterized in that the mounting method of the IC 128 housed in the bottom portion of the base 116 (the lower region of the cavity 116a) is flip chip bonding using bumps 134. By adopting such a configuration, it is not necessary to secure an area where the bonding wire 132 (see FIG. 5) for wire bonding is stretched over the cavity 116a. For this reason, the depth of the cavity 116a required for the base 116 becomes shallow, and the SAW device 110 can be reduced in height accordingly.
Other configurations and operational effects are the same as those of the SAW device shown in the second embodiment.

Next, an electronic device in which the SAW devices 10 and 110 shown in the above embodiment are mounted will be described by taking the cellular phone device shown in FIG. 8 as an example.
In the mobile phone device 200, the audio signal from the transmitter is converted into an electric signal by the microphone 202, modulated by the signal switching unit 206 including a demodulator / codec, etc., frequency-converted, etc. by the transmission unit 208, and the antenna. It is transmitted to a base station (not shown) via 212.

On the other hand, a signal transmitted from the base station is received via the antenna 212, converted in frequency by the receiving unit 214, converted into an audio signal by the signal switching unit 206, and output from the speaker 204.
The operation of the cellular phone device 200 in which such signal control is performed is entirely controlled by a CPU (Central Processing Unit) 216. The CPU 216 also controls the operation of the input / output unit 218 such as a liquid crystal screen and a keyboard, the memory 220 that records a control program, a telephone directory, and the like, and the changeover switch 210 that controls transmission and reception of signals.

  In the mobile phone device 200 having the basic configuration as described above, the above-described SAW devices 10 and 110 are particularly connected to the CPU 216 and serve as a basic clock of the CPU 216 and the like. The above-described SAW device can also be used as a filter or a local oscillator in the transmission unit 208 or the reception unit 214.

  In the SAW device shown in the above embodiment, only the IC is shown as the electronic component to be mounted in the package, but even when other electronic components are mounted, it does not depart from the SAW device according to the present invention. . In the above embodiment, the size of the opening formed in the TAB substrate is equal to the size of the SAW element piece, but at least the excitation electrode formed in the SAW element piece is exposed to the opening side of the cavity. As long as it is in a state in which it can be achieved. In the embodiment, the SAW element piece is shown in the drawing as having a two-port excitation electrode, but it may naturally have another configuration.

It is a figure which shows 1st Embodiment which concerns on the piezoelectric device of this invention. It is a top view which shows the shape of the TAB board | substrate used for embodiment of this invention. It is a top view which shows a SAW element piece single-piece | unit. It is a flow which shows the outline of the process of manufacturing the piezoelectric device which concerns on 1st Embodiment. It is a figure which shows 2nd Embodiment based on the piezoelectric device of this invention. It is a flow which shows the outline of the process of manufacturing the piezoelectric device which concerns on 2nd Embodiment. It is a figure which shows 3rd Embodiment which concerns on the piezoelectric device of this invention. It is a figure which shows the example of the electronic device carrying the piezoelectric device of this invention.

Explanation of symbols

  10, 110 ......... Surface acoustic wave device (SAW device), 12, 112 ......... Surface acoustic wave element (SAW element), 14, 114 ......... Package, 16, 116 ......... Package base (base) ), 16a, 116a ......... cavity, 18, 118 ......... lid, 20, 120 ......... seal ring, 22, 122 ...... TAB substrate, 128 ...... integrated circuit (IC).

Claims (8)

A piezoelectric device in which a surface acoustic wave element is mounted in a package base,
A substrate having an opening formed on the plate surface;
A surface acoustic wave element piece mounted with the excitation electrode opposed to the opening with respect to the substrate,
The substrate is disposed in the package base such that the excitation electrode formed on the surface acoustic wave element piece faces the upper opening side of the package base, and the surface acoustic wave element piece is projected from the opening part. A piezoelectric device characterized in that the piezoelectric device is supported on the substrate by a lead. A piezoelectric device in which an electronic component is mounted on the bottom in a package base, and a surface acoustic wave element piece is mounted on the electronic component,
A board that spans the upper space of the electronic component and has an opening formed on the plate surface,
The surface acoustic wave element piece is mounted on the substrate in a state where the excitation electrode faces the opening, and is disposed so that the excitation electrode faces the upper opening side of the package base. A piezoelectric device characterized in that the piezoelectric device is supported by a lead. A package base having a cavity; a lid for sealing the opening of the package base; an element piece having a configuration in which an excitation electrode and an extraction electrode are formed on a piezoelectric member;
An insulating substrate with conductive leads and openings ;
An electronic component,
The element piece is mounted on the substrate so as to electrically connect the lead and the lead electrode,
Mounting the electronic component on the bottom of the cavity;
The substrate is mounted on the package base so as to be spanned between the side walls in the cavity,
The lead and the electrode pad formed on the package base are electrically connected,
A piezoelectric device, wherein the package base and the element piece are brought into a non-contact state, and the excitation electrode is exposed from the opening of the substrate and the opening of the package base .   The piezoelectric device according to claim 3, wherein the element piece is disposed above the electronic component.   5. The piezoelectric device according to claim 3, wherein the substrate is connected and fixed to the package base on each side of the side wall. Said electronic component, a piezoelectric device according to any one of claims 2 to 5, characterized in that mounted by flip chip bonding. An electronic apparatus comprising the piezoelectric device according to any one of claims 1 to 6 . A translucent material is used for the lid that seals the opening of the package base of the piezoelectric device according to any one of claims 1 to 6 .
A method of manufacturing a piezoelectric device, wherein the frequency is adjusted by adjusting the thickness of the excitation electrode after sealing the package base.

Images