JP2002198739A - Surface mount piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a defect that an adhered part is exfoliated due to the self- weight of a piezoelectric vibration element for a period when the support by a conductive adhesive is weak because of the uncured adhesive when one end of the piezoelectric vibration element is supported onto small circuit components such as chip components by the conductive adhesive. SOLUTION: The surface mount piezoelectric oscillator is provided with a package main body 21 that has an external electrode at its bottom part and an IC mount use conductive pad 21b in continuity with the external electrode on the conduction pad of the package main body, the piezoelectric vibration element 23 at least one edge of which is supported by the conductive adhesive B to an upper electrode 22c on the IC chip, and a cover member 24 that applies air-tight sealing to the package main body including the IC chip and the piezoelectric vibration element, and the IC chip has a length in excess of the distance from the one end edge of the piezoelectric vibration element to a position of the gravity center.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a surface-mount type piezoelectric oscillator, and more particularly to a surface-mount type piezoelectric oscillator having a piezoelectric oscillator having a piezoelectric vibrating element and a circuit component constituting an oscillation circuit, which is simplified and reduced in size. Type piezoelectric oscillator.

[0002]

2. Description of the Related Art With the rapid progress of cost reduction and miniaturization accompanying the spread of mobile communication devices such as mobile phones, piezoelectric oscillators such as crystal oscillators used as frequency control devices in these communication devices have been developed. However, there is an increasing demand for cost reduction, size reduction, and thickness reduction. In response to such demands, in addition to a crystal oscillator, an oscillator circuit including a frequency adjustment circuit, a frequency temperature compensation circuit, etc. is integrated, and circuit components that are made into ICs are housed in one package to reduce the size. Is being planned.

[First Conventional Example] In the conventional piezoelectric oscillator shown in FIG. 5, a circuit component 4 formed into an IC on the inner bottom surface of a package body 1 having a recess 2 and a step 3 is formed by a flip chip method or the like. At the same time as mounting, one end of the piezoelectric vibrating element 5 is cantilevered by the conductive adhesive B on the electrode on the step 3 provided on the inner wall of the recess 2, and the metal lid 6 is fixed on the upper surface of the outer frame of the package body 1. (See, for example, JP-A-7-3361).
No. 79). In this piezoelectric oscillator, the circuit component 4 is mounted on the inner bottom surface in the same recess 2 and is supported on the step 3 so that the piezoelectric vibrating element 5 is located directly above the circuit component 4 to achieve compactness. ing. However, this type of piezoelectric oscillator has a structure in which the step 3 projects inward from the inner wall of the recess, and avoids contact with the step 3 when the circuit component 4 is mounted on the inner bottom surface of the recess. For this reason, it is necessary to secure a sufficient space between the step 3 and the circuit components, and thus there is a limit to the reduction of the plane area of the entire package. Therefore, there has been a problem that when further miniaturization of the piezoelectric oscillator is required, it cannot cope with it.

FIG. 6 is a schematic view of the configuration of a piezoelectric oscillator described in Japanese Patent Application Laid-Open No. 10-173475, and shows a chip component (chip capacitor or chip capacitor) mounted on the inner bottom surface of a ceramic package body 11 having a recess 12. Is a chip resistor), one end of a piezoelectric vibrating element 14 is electrically and mechanically fixed with a conductive adhesive B or the like on the upper surface of a chip resistor 13, and a metal lid 15 is fixed on the upper surface of the outer frame of the package body 11 by seam welding or the like. Have. However, in this conventional example,
Since the piezoelectric vibrating element 14 is supported by the chip component 13 having a dimension significantly shorter than the longitudinal length of the piezoelectric vibrating element 14, one end of the piezoelectric vibrating element 14 is positioned and mounted on the upper surface of the chip component 13 in a horizontal posture. When the conductive adhesive B is bonded and fixed above, it is necessary to keep a horizontal position by pressing one end of the piezoelectric vibration element 14 using a jig or the like until the conductive adhesive B is cured. . If the pressing force of the piezoelectric vibrating element is released before the conductive adhesive B is cured, the tip of the piezoelectric vibrating element hangs down due to its own weight, and the conductive adhesive from the one end of the piezoelectric vibrating element and the upper surface of the chip component 13 May be peeled off, resulting in poor adhesion or detachment of the piezoelectric vibrating element. In order to solve such a problem, a complicated procedure was required in which one end of the piezoelectric vibrating element had to be kept pressed on the chip component until the adhesive was cured. However, incorporation of an operation of continuously holding down the piezoelectric vibrating elements in all the packages during a process of mass production by batch processing has caused a decrease in productivity. In this conventional example, one end of the piezoelectric vibrating element is fixed at a position on the right side of the center of the chip component 13. In other words, since the width W2 at which the piezoelectric vibration element and the chip component 13 overlap is short,
It is necessary to use a large package body 11 for the length of the chip component 13 protruding leftward from one end of the piezoelectric vibrating element, which is a factor that hinders downsizing of the oscillator.

[Second Conventional Example] Next, as another piezoelectric oscillator, for example, Japanese Unexamined Patent Publication No. 2000-151283 discloses a piezoelectric oscillator in an upper concave portion of a ceramic package having an H-shaped vertical section having upper and lower concave portions. Discloses a structure in which a piezoelectric vibrating element is accommodated and hermetically sealed, and a circuit component formed as an IC is mounted on a ceiling surface of a lower concave portion. Further, the publication discloses a two-stage stacked piezoelectric oscillator in which a package on which circuit components are mounted and a package containing a piezoelectric vibrating element are coupled in a vertical positional relationship. Further, while the circuit component 4 is accommodated in the recess 2 of the package body 1 as shown in FIG. 5, a packaged piezoelectric vibrator (not shown) is mounted on the step 3, and the recess 2 of the package body 1 is further mounted. There is also known an oscillator of a type in which is closed by a metal lid 6. The above-described piezoelectric oscillators have a common point in that the planar area of the entire piezoelectric oscillator is reduced by arranging circuit components and piezoelectric vibrating elements in a vertical positional relationship within a package. Furthermore, the structure common to these oscillators is
The point is that the metal lid is fixed to the upper surface of the outer frame constituting the outer wall portion of the concave portion of the package by seam welding or the like to hermetically seal the concave portion. However, no matter how small the outer shape of the package body is, the bonding area of the sealing portion between the upper surface of the outer frame constituting the outer wall of the package body and the metal lid is reduced, in other words, the upper surface of the outer frame is reduced. Width dimension (Fig. 5
Since there is a limit to the reduction of W1), when the planar area of the package body is reduced to reduce the capacity of the recess, it is necessary to reduce the area of the piezoelectric vibration element accordingly. However, when the area of the piezoelectric vibrating element is reduced, the conductive adhesive used for connecting the piezoelectric vibrating element in the package is in a state close to the excitation electrode,
Vibration energy cannot be concentrated on the portion of the excitation electrode, which adversely affects the characteristics of the oscillator. Furthermore, since the ceramic package and the piezoelectric substrate made of a piezoelectric material such as quartz are connected by a conductive adhesive, a difference in the thermal expansion coefficient of each material causes thermal strain on the piezoelectric vibrating element, adversely affecting the characteristics. Pass

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and a first problem corresponding to the first conventional example is that a piezoelectric vibration element is mounted on a small circuit component such as a chip component. When one end is supported by a conductive adhesive, it is possible to eliminate the problem that the bonded portion is peeled off due to the weight of the piezoelectric vibration element while the holding force of the conductive adhesive is weak because it is in an uncured state. is there. In other words, an object of the present invention is to increase the productivity by eliminating the need for a complicated operation of holding down the adhesive with a jig or the like until the adhesive is cured in order to prevent the adhesive portion from peeling. It is another object of the present invention to solve the problem that a package is increased in size by a part of a chip component projecting laterally from a piezoelectric vibration element. Next, a second problem corresponding to the second conventional example is as follows.
When circuit components and piezoelectric vibrating elements are arranged in a vertical position and packaged, if the package is to be further miniaturized, the area of the piezoelectric vibrating element needs to be reduced, resulting in the characteristics of the piezoelectric vibrating element. The problem is to solve the problem that adverse effects occur on the image.

[0007]

According to a first aspect of the present invention, there is provided a package body having an external electrode on a bottom portion and a conductive pad for mounting an IC on the upper portion and electrically connected to the external electrode. An IC chip conductively connected to the conductive pad of the package body, a piezoelectric vibrating element having at least one end supported by a conductive adhesive or a conductive bump with respect to an upper electrode on the IC chip; A lid member for hermetically sealing the upper surface of the package body including the IC chip and the piezoelectric vibrating element, wherein the IC chip has a length exceeding a distance from the one edge to the center of gravity of the piezoelectric vibrating element. It is characterized by being. According to a second aspect of the present invention, the piezoelectric vibrating element includes a piezoelectric substrate including an ultra-thin vibrating portion and an annular thick portion integrally holding an outer periphery of the vibrating portion, and an excitation formed on the vibrating portion of the piezoelectric substrate. Electrodes and
A pad electrode disposed on the lower surface of the annular thick portion and electrically connected to the excitation electrode, and electrically and mechanically connecting the pad electrode provided on the lower surface of the annular thick portion to an electrode on the IC chip. It is characterized by having done. According to a third aspect of the present invention, the piezoelectric vibrating element includes a rectangular piezoelectric substrate, an excitation electrode formed on a vibrating portion of the piezoelectric substrate, and a pad electrode disposed at an appropriate position on the lower surface of the piezoelectric substrate and electrically connected to the excitation electrode. ,
The pad electrode is electrically and mechanically connected to an upper electrode on the IC chip. A fourth aspect of the present invention is characterized in that the piezoelectric vibrating element is arranged so as to substantially cover the entire length of the IC chip. 6. The surface mounted piezoelectric oscillator according to claim 5, wherein one end of the piezoelectric vibrating element is connected to an electrode on the IC chip so that the other end of the piezoelectric vibrating element overhangs from the edge of the IC chip. A step is provided on the main body, the step extending just below the other end of the piezoelectric vibrating element, and the height of the step is higher than the height of the IC chip. Claim 6 includes a silicon substrate having a circuit element constituting an oscillation circuit, an external electrode provided on the bottom of the silicon substrate, and an upper electrode disposed on the upper surface of the silicon substrate and electrically connected to the external electrode. An IC chip having a planar shape matching the silicon substrate or matching the inside of the silicon substrate, including concave portions on upper and lower surfaces, including an excitation electrode on a vibrating portion on the inner bottom surface of the concave portion, and further including the upper electrode A piezoelectric vibrating element having a pad electrode electrically connected to an excitation electrode on a lower surface thereof, and a lid having a planar shape matching the piezoelectric vibrating element. The lid is sequentially overlapped, the upper electrode and the pad electrode are joined, and the lid is joined to the upper surface of the piezoelectric vibrator. According to a seventh aspect of the present invention, the outer surface of the piezoelectric oscillator except for the external electrodes is covered with an insulating film. An eighth aspect is characterized in that the upper surface of the piezoelectric vibration element is an entire surface electrode.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. [First Embodiment] FIG. 1A is a longitudinal sectional view of a surface mount type piezoelectric oscillator according to a first embodiment of the present invention. The surface-mount type piezoelectric oscillator is, for example, a crystal oscillator 20. The crystal oscillator 20 forms an oscillation circuit including a frequency adjustment circuit, a frequency temperature compensation circuit, and the like on a package body (printed board) 21 made of ceramic or the like. A flat plate-shaped IC chip 22 is mounted, a crystal vibrating element 23 is mounted on the upper surface of the IC chip 22, and the upper surface of the printed board 21 including the IC chip 22 and the crystal vibrating element 23 is further covered with the cover member 2.
4 is used. The package body 21 made of a ceramic plate or the like has external electrodes 21a on its lower surface and has conductive pads 21b for mounting ICs on its upper surface. The IC chip 22 is a bare chip, and each circuit element constituting an oscillation circuit is formed in a silicon substrate 22a by LSI technology, and an external electrode 22b is provided on a lower surface of the silicon substrate 22a, and an upper electrode 22c is provided on an upper surface thereof. I have. The crystal vibrating element 23 includes a crystal substrate 25 including an ultra-thin vibrating portion 25 a and a thick annular thick portion 25 b integrally holding an outer peripheral edge of the vibrating portion 25 a, and a table of a vibrating portion 25 a of the crystal substrate 25. Excitation electrodes 26 formed on the back surface, lead electrodes 26a drawn from the respective excitation electrodes 26, and pad electrodes 26b connected to the respective excitation electrodes 26 via the respective lead electrodes 26a and located on the lower surface of the annular thick portion 25b. When,
Is provided. The pad electrode 26b and the upper electrode 22c of the IC chip 22 are opposed to each other in one-to-one correspondence, and a conductive adhesive, solder,
It is electrically and mechanically connected by connection means B such as a bump. The lid member 24 is made of metal or ceramic, and has an IC
The package body 21 for hermetically sealing the space on the package body 21 including the chip 22 and the quartz vibrating element 23
The lower end surface is fixed on the upper earth electrode 21c by a sealing member such as solder so as to maintain an airtight state. As shown in the figure, of the pad electrodes 26b provided on the lower surface of the annular thick portion, the vibration portion 2
When two pad electrodes facing each other and sandwiching 5a are fixed on the IC chip 22, the IC chip 2
It is necessary to set the lateral dimension of 2 to a length substantially equal to that of the quartz-crystal vibrating element 23. In this case, the depth dimension of the IC chip 22 may be equal to or greater than the depth dimension of the crystal vibrating element 23, but may be narrow as long as the crystal vibrating element 23 can be mounted without tilting. On the other hand, as shown in FIG. 2B, only one pad electrode 26b is connected to the IC chip 22.
If you use a cantilevered support structure that is fixed on top,
The lateral dimension of the chip 22 is, as shown in FIG.
3 may be significantly shorter than the lateral dimension, or may be substantially the same as the crystal resonator element 23.

FIG. 1B shows a modified embodiment in which the quartz vibrating element is supported in a cantilever manner.
The length L1 of the IC chip 22 can be reduced from the left edge of the crystal resonator element 23 to a length corresponding to the position of the center of gravity. That is, 1/2 of the length L2 of the quartz vibrating element 23.
By reducing the length of the IC chip 22 to the extent or the position of the center of gravity of the crystal vibrating element 23 with one end (left end) supported by the conductive adhesive, the conductive adhesive is cured. In this step, the crystal vibrating element 23 is stably mounted without falling off the IC chip and the pad electrode 2
6b (disposed only at the left end of the crystal resonator element) can be fixed. Therefore, even when mass-producing by batch processing, it is possible to omit a complicated step of waiting for the curing of the adhesive while holding down the bonding portions of the crystal vibrating elements 23 on all the IC chips 22, thereby improving mass productivity. be able to. Also, as the IC chip to be used, it is possible to use a type having various dimensions in the lateral direction, and it is not always necessary to use an IC chip having an area equivalent to that of a quartz vibrating element. The degree increases. Although a flat printed circuit board is used as the package body 21 in this embodiment, it is a matter of course that a box-shaped package body having a concave portion on the upper surface may be used. In this case, the upper surface of the package body will be closed with a flat metal lid. Further, when the crystal vibrating element 23 is fixed on the IC chip 22 with the conductive bumps, the curing time is not required unlike the conductive adhesive, so that it is not necessary to consider the position of the center of gravity described above. It is preferable to place the IC chip 22 on the IC chip because the weight applied to the connection point between the IC chip 22 and the package body 21 becomes uniform, and the left end of the crystal unit 23 is located as close to the left end of the IC chip 22 as possible. By approaching, the overall size can be reduced.

According to the crystal oscillator according to the embodiment shown in FIGS. 1A and 1B, the crystal resonator element is mounted directly on the IC chip mounted on the package body. There is no need to protrude a step on the inner wall to support the crystal resonator, and there is no need to secure space for incorporating circuit components between the steps, making it possible to reduce the planar shape of the package. Become. The length L1 of the IC chip 22 may be as small as having a length exceeding the distance from one edge (the left edge in the drawing) of the piezoelectric vibrating element 23 to the position of the center of gravity. And the degree of freedom in design increases. Further, the amount of the IC chip 22 protruding from the edge of the piezoelectric vibrating element 23 is made as small as possible, and the piezoelectric vibrating element 23 is assembled so as to substantially cover the entire length of the IC chip 22. And the amount of protrusion in the lateral direction beyond the dimension of the package is reduced, and the plane area of the package can be reduced. When one end edge of the crystal resonator element 23 is fixed on the IC chip with a conductive adhesive and cantilevered, even if the crystal resonator element 23 is held in a horizontal position parallel to the upper surface of the IC chip at the time of bonding. In addition, due to an upward stress generated in the adhesive during curing of the adhesive, the one end edge on the non-adhesive side is fixed with a slight upward inclination. For this reason, FIG.
In either case (b), after the adhesive is cured, the lower surface of the crystal vibrating element 23 except for the left end edge of the annular thick portion 23b is held in a state separated from the upper surface of the IC chip 22. Therefore, there is no problem that free vibration of the vibrating portion is hindered by contact between the upper surface of the IC chip and the lower surface of the annular thick portion in a wide range.

Next, FIG. 2A is a longitudinal sectional view of a modified embodiment of the crystal oscillator shown in FIG. 1A. As a crystal vibrating element 23 mounted on an IC chip 22, a rectangular (flat) plate is used.
1A is different from the one shown in FIG. That is, the crystal vibrating element 23 used in the crystal oscillator according to this embodiment is a flat crystal substrate 27.
And excitation electrodes 27a respectively formed on the front and back of the quartz substrate 27
A lead electrode 27b drawn out from each excitation electrode 27a toward both ends, and a pad electrode 27 connected to each lead electrode 27b and arranged on the lower surface of the quartz substrate 27.
c. In this embodiment, the quartz vibrating element 23
Pad electrodes 27c respectively arranged at two opposite edges of
Is fixed to the upper surface of the IC chip by bonding. However, two pad electrodes 27c are arranged along one edge, and each pad electrode 27c arranged on the one edge is connected to a conductive adhesive.
It may be configured to be cantilevered by being adhesively fixed to the upper surface of the C chip. In this case, at the time of the bonding operation, the lower surface of the free end of the crystal resonator element 23 is brought into contact with the upper surface of the IC chip, and each pad electrode 27c provided on one end is fixed to the upper electrode 22c with a conductive adhesive. The free end of the crystal resonator element is lifted upward by the upward stress generated inside the adhesive during the curing of
Since it is fixed in a non-contact state with the C chip 22, free vibration of the crystal vibrating element 23 is not hindered by the IC chip 22. With respect to other structural features, effects, and the like, what is described with reference to FIG.

Next, FIG. 2B is a modified embodiment of FIG. 1B, and uses an IC chip 22 having a dimension L1 much smaller than the total length L2 of a flat crystal vibrating element 23. A characteristic is that the crystal vibrating element 23 is cantilevered. That is, FIG. 2B shows a modified embodiment in which the strip-shaped quartz-crystal vibrating element 23 is supported in a cantilever manner. In this case, the length L1 of the IC chip 22 is measured from the left edge of the quartz-crystal vibrating element 23. The length can be reduced to a length corresponding to the distance to the position of the center of gravity. That is, the length of the IC chip 22 is reduced to about 1/2 of the length L2 of the quartz vibrating element 23 or to the center of gravity of the quartz vibrating element 23 with one end (left end) supported by a conductive adhesive. By shortening the length, it is possible to stably mount the crystal vibrating element 23 on the IC chip and bond and fix the pad electrode 26b (disposed only at the left end of the crystal vibrating element) with a conductive adhesive. It becomes possible. In other words, in this case, the lower surface of the quartz crystal vibrating element 23 is positioned at the center of gravity when the IC chip 22 is placed in contact with the upper surface of the right end of the IC chip 22 in FIG. Is located on the IC chip, and therefore, before the conductive adhesive is cured, even if the crystal vibrating element 23 is not pressed onto the upper surface of the IC chip 22 by a special jig or the like, the crystal vibrating element As a result, there is no danger that the adhesive portion will peel off.
Therefore, even when mass-producing by batch processing, all ICs
It is possible to omit a complicated process of waiting for the hardening of the adhesive while keeping the bonded portion of the crystal vibrating element 23 on the chip 22, thereby improving mass productivity. Also, as the IC chip to be used, it is possible to use a type having various dimensions in the lateral direction, and it is not always necessary to use an IC chip having an area equivalent to that of a quartz vibrating element. The degree increases. Although a flat printed circuit board is used as the package body 21 in this embodiment, it is a matter of course that a box-shaped package body having a concave portion on the upper surface may be used. In this case,
The upper surface of the package body will be closed by a flat metal lid.

Next, FIG. 3 shows a modification of the embodiment shown in FIG. 1 or FIG. 2. This surface mount type piezoelectric oscillator has an external electrode 21a on the bottom and a recess 21A on the upper surface. A package body 21, an IC chip 22 mounted on a conductive pad 21b provided on the inner bottom surface of the recess 21A,
The conductive adhesive B (or the conductive adhesive B (or
It has a crystal vibrating element 23 whose one end is cantilevered using a bump), and a lid member 24 fixed to the upper surface of the outer frame of the package body 21 to hermetically seal the recess 21A.
The crystal vibrating element 23 may be either a type in which the thin vibrating portion shown in FIG. 1 is supported by an annular thick portion or a strip type shown in FIG. The characteristic configuration of the oscillator according to the present embodiment is the
A step 21B is arranged on one of the inner walls, and the upper surface of the step 21B is located immediately below the other end of the crystal resonator element 23 overhanging from the edge of the IC chip 22. The height H2 of the step 21B is set to be slightly higher than the height H1 of the IC chip 22 mounted on the inner bottom surface of the recess. With this configuration, when the crystal resonator element 23 is mounted on the IC chip 22, the lower surface of the overhanging other end is set to the step 21 </ b> B.
In a state of being placed on the upper side, an operation of bonding one edge to the upper electrode 22c can be performed. Therefore, the quartz vibrating element 2
Excitation electrodes 26a and 27 easily peeled off on the lower surface of 3
It is possible to eliminate such a problem that a is rubbed against the upper surface of the IC chip and is damaged or peeled off. In the state where the conductive adhesive B is hardened, the other end of the crystal vibrating element is urged upward by the upward stress generated in the conductive adhesive. And the other end is held in a state sufficiently separated from the upper surface of the step 21B.

[Second Embodiment] FIGS. 4A, 4B and 4C are a perspective view, an exploded perspective view and a perspective view of a surface mount type piezoelectric oscillator according to a second embodiment of the present invention. It is A sectional drawing. This surface mount type piezoelectric oscillator is, for example, a crystal oscillator 3
This crystal oscillator 31 is formed by sequentially laminating a crystal vibrating element 33 and a lid 34 made of a crystal plate on a flat IC chip 32 constituting an oscillation circuit including a frequency adjustment circuit, a frequency temperature compensation circuit, and the like. It has an integrated configuration. The IC chip 32 is a bare chip. Each circuit element constituting an oscillation circuit is formed on a silicon substrate 40 by LSI technology, and external electrodes 41 are formed on the lower surface of the silicon substrate 40.
Is provided with an upper electrode 42 on the upper surface. Crystal vibrating element 3
3 has a configuration in which the peripheral portion of the ultra-thin vibrating portion 45 is integrally supported by a thick annular thick portion 46.
Excitation electrodes 47 and 48 are formed at the center of the front and back surfaces of the lead electrodes 47 and 48.
Pad electrodes 47b and 48b are arranged at the ends of the terminals a and 48a. Each of the pad electrodes 47b and 48b is located on the lower surface of the annular thick portion (thick portion) 46. Crystal vibrating element 3
3 has a size and a shape set so as to be in close contact with the upper surface of the IC chip 32 in a matching state, and the pad electrodes 47b and 48b provided on the lower surface of the annular thick portion 46 are
It is arranged so as to correspond to each upper electrode 42 on the IC chip 32 on a one-to-one basis. Lid 34 made of quartz plate or glass
Are set in size and shape so as to be in close contact with the upper surface of the crystal vibrating element 33 and to be aligned. IC chip 3
2 and a quartz vibrating element 33
The lid 34 made of a quartz plate is made of a material having the same thermal expansion coefficient. This crystal oscillator 31 includes an IC chip 32
The crystal vibrating element 33 and the lid 34 are sequentially stacked on top of each other, and the upper electrode 32 and the pad electrodes 47b and 48b are joined by a binder such as a conductive adhesive or solder, a gold bump, or the like. It is completed by bonding or bump-fixing to the upper surface of the portion 46. By batch processing, large area I
When manufacturing using a C chip base material, a crystal vibrating element base material, and a base material of a lid, each base material is overlapped and a required portion is adhered, and then cut into individual pieces to obtain individual crystals. An oscillator 21 is obtained.

When the IC chip 32, the crystal unit 33 and the lid 34 are bonded by bonding or the like as described above,
Fine gaps are generated between the members, and there is a possibility that the airtightness in the upper and lower recesses of the crystal resonator element 33 may be insufficient. Therefore, the entire outer surface of the completed crystal oscillator (excluding the external electrodes 41 of the IC chip 32) is covered with silicon (Si) such as SiO _2.
A system thin film (insulating film) is uniformly formed by a method such as vapor deposition or sputtering to seal fine voids scattered in various places and maintain airtightness inside. It is also effective in covering the part where the conductor excluding the external electrode 41 is exposed on the outer surface with a silicon-based thin film for insulation. In such a configuration, since the IC chip, the quartz vibrating element, the lid, and the deposited film are made of a silicon-based material and have substantially equal thermal expansion coefficients, cracks are generated in the deposited film due to a temperature change such as heating. The airtightness does not decrease. Alternatively, the entire outer surface of the oscillator excluding the external electrodes 41 of the IC chip 32 may be molded with an insulating resin film (insulating film) to seal fine voids, and the exposed conductor may be insulated. Good. Also, by coating the mold,
The bonding strength between the members can be increased. Further, as shown in FIG.
7A, or both the lid and the quartz-crystal vibrating element may have a structure having a depression on one side as shown in FIG.
Needless to say, the size of the IC chip and the size of the crystal resonator element do not necessarily have to match.

According to the oscillator of the present invention having the above-described structure, since the metal cover is not fixed to the upper surface of the outer frame of the package body having the recessed portion by welding as shown in FIG. The area corresponding to the total width of the outer frame of the main body can be reduced, and the plane area of the entire oscillator can be reduced. In addition, the downsizing of the oscillator according to the present invention does not involve a reduction in the area of the quartz vibrating element. Therefore, the conductive adhesive as described in the conventional example interferes with the excitation electrode and hinders the concentration of the vibration energy, thereby reducing the oscillator. The problem of deteriorating characteristics is eliminated. Further, the IC chip 32, the quartz vibrating element 33, and the lid 34 are all made of a silicon-based material,
That is, since they are made of silicon, quartz, glass, etc., their thermal expansion coefficients are almost equal, and the quartz crystal vibrates due to thermal distortion when the conductive adhesive or the like is cooled when the members are joined by the conductive adhesive or solder. No fluctuation occurs in the resonance frequency of the element. Further, as shown in the figure, the IC chip 32, the crystal vibrating element 33, and the lid 34 are overlapped with each other and are simply joined at important points, so that they are suitable for mass production by batch processing. That is, a large-area IC chip preform, a large-area crystal resonator element preform, and a large-area lid preform are stacked in a state where the positional relationship of individual pieces included in each preform is matched. Oscillator is completed by joining required portions and dividing into individual pieces, and then forming a required thin film on the outer surface of each of the oscillators, coating with a mold resin, and the like.

[0017]

As described above, according to the present invention, when one end of the piezoelectric vibrating element is supported on a small circuit component such as a chip component by a conductive adhesive, the piezoelectric vibrating element is in an uncured state and thus has a conductive property. It is possible to eliminate the problem that the bonded portion is peeled off by the weight of the piezoelectric vibrating element during the period in which the holding force of the conductive adhesive is weak. In other words, productivity can be improved by eliminating the need for a complicated work of holding down the adhesive with a jig or the like until the adhesive is cured in order to prevent the adhesive portion from peeling. In addition, since a part of the chip component protrudes laterally from the piezoelectric vibrating element, it is possible to solve the problem that the package is increased in size. Also, when the circuit components and the piezoelectric vibrating element are arranged in a vertical position and packaged, if the package is to be further miniaturized, it is necessary to reduce the area of the piezoelectric vibrating element. Can be solved.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view of a surface-mount type piezoelectric oscillator according to a first embodiment of the present invention, and FIG. 1B is a diagram showing a modified embodiment in which a quartz-crystal vibrating element is supported in a cantilever manner.

2A is a longitudinal sectional view of a modified embodiment of the crystal oscillator of FIG. 1A, and FIG. 2B is a longitudinal sectional view of a modified embodiment of FIG. 1B.

FIG. 3 is a longitudinal sectional view of a modification of the embodiment shown in FIG. 1 or FIG.

4A is a perspective view of a surface-mount type piezoelectric oscillator according to a second embodiment of the present invention, FIG. 4B is an exploded perspective view, and FIG.
Is a sectional view taken along the line AA, and (d) and (e) are sectional views of the modified embodiment.

FIG. 5 is a longitudinal sectional view of a conventional oscillator.

FIG. 6 is a longitudinal sectional view of another conventional oscillator.

[Explanation of symbols]

Reference Signs List 20 crystal oscillator, 21 package body (printed circuit board), 21 a external electrode, 21 b conductive pad, 22
IC chip, 22a Silicon substrate, 22b External electrode, 22c Upper electrode, 23 Quartz crystal vibrating element, 24 Lid member, 25 Quartz substrate, 25a Vibrating part, 25b Ring thick part, 26 Excitation electrode, 26a Lead electrode, 26b
Pad electrode, 27 quartz substrate, 27a excitation electrode, 2
7b lead electrode, 27c pad electrode, 31 crystal oscillator, 32 IC chip, 33 crystal vibrating element, 34
Lid, 40 silicon substrate, 41 external electrode, 42 upper electrode, 45 vibrating part, 46 annular thick part, 47 excitation electrode.

Continued on the front page F term (reference) 5J079 AA03 BA43 BA44 FA01 HA07 HA16 5J108 BB02 CC04 EE03 EE07 EE18 FF01 GG03 GG08 GG14 GG15 GG16 JJ04 KK03

Claims (8)

[Claims] 1. A package body having an external electrode on a bottom and a conductive pad for mounting an IC on the upper part and electrically connected to the external electrode, an IC chip conductively connected on the conductive pad of the package main body, A piezoelectric vibrating element having at least one edge supported by a conductive adhesive or a conductive bump with respect to an upper electrode on the IC chip, and a lid member for hermetically sealing the upper surface of a package body including the IC chip and the piezoelectric vibrating element. Wherein the IC chip has a length exceeding a distance from the one edge of the piezoelectric vibrating element to a position of a center of gravity. 2. The piezoelectric vibrating element comprises: a piezoelectric substrate having an ultra-thin vibrating portion and an annular thick portion integrally holding an outer periphery of the vibrating portion; and an excitation formed in the vibrating portion of the piezoelectric substrate. An electrode, and a pad electrode disposed on the lower surface of the annular thick portion and electrically connected to the excitation electrode. The pad electrode provided on the lower surface of the annular thick portion is connected to the IC.
2. The surface mount type piezoelectric oscillator according to claim 1, wherein the surface mount type piezoelectric oscillator is electrically and mechanically connected to an electrode on a chip. 3. The piezoelectric vibrating element comprises: a strip-shaped piezoelectric substrate; an excitation electrode formed on a vibrating portion of the piezoelectric substrate; and a pad electrode disposed at an appropriate position on a lower surface of the piezoelectric substrate and electrically connected to the excitation electrode. The surface mount type piezoelectric oscillator according to claim 1, wherein the pad electrode is electrically and mechanically connected to an upper electrode on the IC chip. 4. The surface mount type piezoelectric oscillator according to claim 1, wherein the piezoelectric vibrating element is disposed so as to substantially cover the entire length of the IC chip. 5. A surface-mounted piezoelectric oscillator in which one end of the piezoelectric vibrating element is connected to an electrode on the IC chip so that the other end of the piezoelectric vibrating element overhangs from the edge of the IC chip. On the main body, a step extending just below the other end of the piezoelectric vibrating element is arranged, and the height of the step is
5. The surface mount type piezoelectric oscillator according to claim 1, wherein the height is higher than the height of the C chip. 6. A silicon substrate provided with a circuit element constituting an oscillation circuit, an external electrode provided on a bottom portion of the silicon substrate, and an upper electrode disposed on an upper surface of the silicon substrate and electrically connected to the external electrode. An IC chip having a planar shape matching the silicon substrate or matching the inside of the silicon substrate, including concave portions on upper and lower surfaces, including an excitation electrode on a vibrating portion on the inner bottom surface of the concave portion, and further including the upper electrode A piezoelectric vibrating element having a pad electrode electrically connected to an excitation electrode on the lower surface thereof, and a lid having a planar shape that matches the piezoelectric vibrating element. The piezoelectric vibrating element and the A surface-mounted piezoelectric oscillator, wherein lids are sequentially stacked to join the upper electrode and the pad electrode, and the lid is further joined to an upper surface of a piezoelectric vibrator. 7. The surface mount type piezoelectric oscillator according to claim 6, wherein an outer surface of said piezoelectric oscillator excluding said external electrode is covered with an insulating film. 8. The surface mount type piezoelectric oscillator according to claim 5, wherein an upper surface of the piezoelectric vibration element is an entire surface electrode.