JP2000114874A - Saw oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain improvement in electric characteristics such as high frequency characteristics, miniaturization, reduction in man-hours for assembly, cost-down and improvement in impact resistance. SOLUTION: Concerning a main body 4 of an oscillator, a SAW resonator forming area 1A for forming a SAW resonator 2 and an IC chip mounting area 1B for mounting an IC chip 3 for driving the SAW resonator 2 adjacently to this SAW resonator forming area 1A are provided on a piezoelectric substrate 1, the SAW resonator 2 is formed in the SAW resonator forming area 1A and the flip chip mounting of the IC chip 3 is performed in the IC chip mounting area 1B. This main body 4 of oscillator is housed and fixed in a package and the upper opening of the package is sealed with a lid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a SAW resonator,
The present invention relates to a SAW oscillator composed of an IC chip (integrated circuit chip) for driving the SAW resonator and applied to a wireless communication device such as a small wireless device.

[0002]

2. Description of the Related Art Conventionally, as an example of this type of SAW oscillator, an IC chip in which an SAW resonator having a comb-shaped electrode or the like provided on a piezoelectric substrate and an oscillation circuit for driving the SAW resonator are integrated. And S in the package
An AW resonator and an IC chip which are individually housed are known. The electrical connection between the SAW resonator and the IC chip and the electrical connection between the electrode of the IC chip and the external connection electrode of the package are performed by wire bonding using gold or aluminum wires. .

[0003]

When the SAW resonator and the IC chip are housed independently in the package as described above, and the wiring between the SAW resonator and the IC chip is performed by wire bonding, the following is required. There is such a problem.

[0004] First, the wiring is generally long, and in this case, the high-frequency characteristics deteriorate due to the influence of stray inductance and stray capacitance.

Second, there is a possibility that the electrical characteristics may vary due to variations in the processing accuracy of wire bonding.

Third, when the SAW resonator and the IC chip are mounted at a considerable distance from each other, the temperature between the SAW resonator and the IC chip varies, and a temperature sensor is provided on the IC chip. S based on the temperature detected by the temperature sensor
This is not preferable when temperature compensation of the AW resonator is performed.

The present invention has been made in view of the above points, and has as its object to improve electric characteristics such as high-frequency characteristics,
It is an object of the present invention to provide a SAW oscillator that is reduced in size, reduced in the number of assembly steps, reduced in cost, and improved in impact resistance.

[0008]

Means for Solving the Problems To solve the above problems and achieve the object of the present invention, each of the inventions according to claims 1 to 8 is configured as follows.

That is, according to the first aspect of the present invention, a SAW formed by providing at least a comb-shaped electrode on a piezoelectric substrate is provided.
In a SAW oscillator comprising a resonator and an IC chip in which an oscillation circuit for driving the SAW resonator is integrated, the piezoelectric substrate includes a SAW resonator forming region for forming the SAW resonator and the IC chip. An IC chip mounting area for mounting a chip is provided, and the IC chip is mounted in the IC chip mounting area.

According to a second aspect of the present invention, in the SAW oscillator according to the first aspect, the IC chip is mounted by flip-chip mounting.

According to a third aspect of the present invention, in the SAW oscillator according to the first or second aspect, the piezoelectric substrate on which the SAW resonator is formed and the IC chip is mounted is housed in a package. At the same time, the piezoelectric substrate is fixed in the package by connecting an external input / output terminal provided in the IC chip mounting area and an external input / output terminal provided in the package with a conductive adhesive. I made it.

According to a fourth aspect of the present invention, in the SAW oscillator according to the first, second, or third aspect,
The IC chip includes, in addition to the oscillation circuit, a temperature sensor that detects the temperature of the SAW resonator, and a temperature compensation circuit that performs temperature compensation of the SAW resonator based on the temperature detected by the temperature sensor.

According to a fifth aspect of the present invention, there is provided an SAW resonator formed by providing at least a comb-shaped electrode on a piezoelectric substrate, and an IC chip in which an oscillation circuit for driving the SAW resonator is integrated. A SAW oscillator comprising: a surface opposite to the surface on which the comb-shaped electrodes of the piezoelectric substrate are provided; and an IC chip mounting region for mounting the IC chip, and the IC chip mounted in the IC chip mounting region. It is.

According to a sixth aspect of the present invention, in the SAW oscillator according to the fifth aspect, the IC chip is mounted by flip-chip mounting.

According to a seventh aspect of the present invention, in the SAW oscillator according to the fifth or sixth aspect, the piezoelectric substrate on which the SAW resonator is formed and the IC chip is mounted is housed in a package. At the same time, the piezoelectric substrate is fixed in the package by connecting an external input / output terminal provided in the IC chip mounting area and an external input / output terminal provided in the package with a conductive adhesive.

According to the invention described in claim 8, in the SAW oscillator according to claim 5, 6, or 7,
The IC chip includes, in addition to the oscillation circuit, a temperature sensor that detects the temperature of the SAW resonator, and a temperature compensation circuit that performs temperature compensation of the SAW resonator based on the temperature detected by the temperature sensor.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the entire configuration of a first embodiment of a SAW oscillator according to the present invention. FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 is a perspective view of the oscillator main body. FIG. 4 is a diagram showing a mounting state of the IC chip.

The SAW oscillator according to the first embodiment has the structure shown in FIG.
As shown in FIG. 1, an oscillator main body 4 in which a SAW resonator 2 is formed on a piezoelectric substrate 1 and an IC chip 3 for driving the SAW resonator 2 is mounted on the piezoelectric substrate 1 is provided. As shown in FIG. 2, the oscillator body 4 is housed and fixed in a package 5 with its front side facing downward, and the upper opening of the package 5 is sealed with a lid 6.

As shown in FIG. 3, the oscillator body 4 includes a SAW resonator forming area 1A in which a SAW resonator 2 is formed on a piezoelectric substrate 1 made of quartz, langasite, LBO, sapphire, diamond, or the like. An IC chip mounting area 1B for mounting the IC chip 3 adjacent to the SAW resonator forming area 1A is provided, and the SAW resonator forming area 1A is provided.
SAW resonator 2 is formed in IC chip mounting area 1
IC chip 3 is flip-chip mounted on B.

The reason why the IC chip mounting area 1B is provided on the piezoelectric substrate 1 in addition to the SAW resonator forming area 1A is that the SAW resonator forming area 1A is formed in the SAW resonator forming area 1A.
The vibration of the surface acoustic wave generated by the W resonator 2 is limited to the SAW resonator forming region 1A, and the influence of the vibration hardly reaches the IC chip mounting region 1B orthogonal to the surface acoustic wave transport direction. is there.

On the surface in the SAW resonator forming region 1A and in the width direction of the piezoelectric substrate 1, a pair of comb-shaped electrodes 7 and 8 made of aluminum or the like having a predetermined line width and a line interval are formed by photolithography. , A pair of reflectors 9,
10 are provided, whereby the SAW resonator 2 is formed.

The IC chip 3 has a temperature sensor for measuring the temperature of the SAW resonator 2 and a temperature sensor for measuring the temperature of the SAW resonator 2 in addition to the oscillation circuit for driving the SAW resonator 2. And a temperature compensating circuit, which are integrated on a single chip. As shown in FIG. 4, the IC chip 3 has a plurality of mounting bumps (projection electrodes) 17 on its lower surface.

As shown in FIG. 3, conductive patterns 11 to 14 connected to the IC chip 3 are provided on the surface in the IC chip area 1B.
Reference numeral 14 is connected to external input / output terminals 11A to 14A provided at an end on the surface. Further, conductive patterns 15 and 16 for connecting the IC chip 3 and the comb-shaped electrodes 7 and 8 are provided on the surface in the IC chip region 1B and on the surface in the SAW resonator forming region 1A, respectively. Then, as shown in FIG. 4, each bump 17 provided on the lower surface of the IC chip 3 is connected to each part of the corresponding conductive pattern 11 to 16 by a solder 18.
The chip 3 is so-called flip-chip mounted in the IC chip area 1B.

As shown in FIG. 1, a pair of rectangular parallelepiped terminal blocks 25 and 26 are provided at predetermined intervals in the length direction of the package 5, and a plurality of terminal blocks 25 and 26 are provided on the terminal blocks 25 and 26. External input / output terminals 20 to 23 are provided. Then, the oscillator main body 4 is housed in the package 5 with its front side facing down, and the external input / output terminals 11A to 14A provided on the piezoelectric substrate 1 and the external input / output terminals 20 to 23 opposed thereto are electrically connected. The oscillator main body 4 is supported and fixed in the package 5 by electrical connection with the conductive adhesive 24.

As described above, in the SAW oscillator according to the first embodiment, an IC chip mounting area 1B for mounting an IC chip 3 is provided on the piezoelectric substrate 1 in addition to the SAW resonator forming area 1A. The IC chip 3 is flip-chip mounted on the IC chip mounting area B. Therefore, the electrical connection distance between the SAW resonator 2 and the IC chip 3 is shortened, so that stray inductance and stray capacitance can be reduced, and electric characteristics such as high-frequency characteristics are improved.

In the SAW oscillator according to the first embodiment, a temperature sensor is provided on the IC chip 3 and the temperature sensor and the SAW resonator 2 are brought close to each other. The accuracy is improved, so that the temperature compensation of the SAW resonator 2 by the temperature compensation circuit becomes more appropriate.

Further, in the SAW oscillator according to the first embodiment, the IC chip 3 is flip-chip mounted on the IC chip mounting area 1B, and the package 5 of the piezoelectric substrate 1 is mounted.
Since a conductive adhesive is used for mounting inside, the number of assembly steps, the production cost, and the impact resistance can be improved.

Next, a second embodiment of the SAW oscillator according to the present invention will be described with reference to FIG.

The SAW oscillator according to the second embodiment has the structure shown in FIG.
The oscillator main body 4 of the first embodiment shown in FIG. 5 is replaced with an oscillator main body 4A as shown in FIG.

That is, as shown in FIG. 5, the oscillator body 4A has a pair of comb electrodes 7 on the surface of the piezoelectric substrate 1 in the SAW resonator forming region 1A and in the longitudinal direction of the piezoelectric substrate 1. 8 and a pair of reflectors 9 and 10 are provided. Then, conductive pattern patterns 27 and 28 for connecting the comb-shaped electrodes 7 and 8 and the IC chip 3 are provided on the piezoelectric substrate 1 symmetrically with respect to the length direction, and each of the conductive pattern patterns 27 and 28 is provided. The length is the same, and the high-frequency characteristics are improved as compared with the first embodiment.

The structure of the other parts of the second embodiment is the same as that of the first embodiment, and the description thereof is omitted. In FIG. 5, the same parts as those of FIG. I have.

Next, a third embodiment of the SAW oscillator according to the present invention will be described with reference to FIGS.

FIG. 6 is a perspective view showing the entire configuration of a third embodiment of the SAW oscillator according to the present invention. FIG. 7 is a sectional view taken along line BB of FIG. FIG. 8 is a perspective view of the front side of the oscillator main body. FIG. 9 is a perspective view of the back side of the oscillator main body.

The SAW oscillator according to the third embodiment has the structure shown in FIG.
And as shown in FIG. 7, quartz, langasite, LB
Piezoelectric substrate 3 made of O, sapphire, diamond, etc.
The SAW resonator 32 is formed on the front side of the piezoelectric substrate 31, while the IW for driving the SAW resonator 32
An oscillator main body 34 on which a C chip 33 is mounted is provided.
5, and is fixed, and the upper opening of the package 35 is sealed with a lid 36.

Here, the reason why the IC chip 33 is mounted on the back surface of the piezoelectric substrate 31 is that the vibration of the surface acoustic wave generated by the SAW resonator 32 formed on the surface of the piezoelectric substrate 31 is This is because the vibration is hardly affected on the back surface (back surface side) of the piezoelectric substrate 31.

As shown in FIG. 8, a pair of comb-shaped electrodes 37 and 38 made of aluminum having a predetermined line width and a line interval are formed on the surface of the piezoelectric substrate 31 and in the length direction thereof by photolithography, as shown in FIG. , A pair of reflectors 39,
A SAW resonator 32 is formed.

The right half on the back surface of the piezoelectric substrate 31
As shown in FIG. 3, conductive patterns 41 to 44 connected to the IC chip 33 are provided.
Are connected to external input / output terminals 41A to 44A provided at both ends in the width direction on the back surface. Further, FIG.
As shown in FIG. 9 and FIG. 9, the comb-shaped electrode 3
Conductive patterns 45 and 46 are provided to electrically connect the IC chips 33 with the IC chips 33 at the shortest distance.

The bumps provided on the lower surface of the IC chip 33 are connected to the corresponding conductive patterns 41 to 46 by soldering, so that the IC chip 33 is mounted on the back surface of the piezoelectric substrate 31 by a so-called flip chip. Has been implemented. This mounting is the same as the mounting of the IC chip 3 on the piezoelectric substrate 1 shown in FIG.

The IC chip 33 includes, in addition to an oscillation circuit for driving the SAW resonator 32, a temperature sensor for measuring the temperature of the SAW resonator 32, and a temperature sensor for detecting the temperature of the SAW resonator 32.
A temperature compensation circuit for compensating the temperature of the AW resonator 32 is provided, and these are integrated on one chip.

As shown in FIG. 6, a pair of rectangular parallelepiped terminal blocks 51, 52 are provided at predetermined intervals in the length direction of the package 35, and a plurality of terminal blocks 51, 52 are provided on the terminal blocks 51, 52. External input / output terminals 53 to 56 are provided. Then, the oscillator body 34 is housed in the package 35 with its back side facing down, and the external input / output terminals 41A to 44A provided on the back surface of the piezoelectric substrate 31 and the external input / output terminals 53 to 56 And the conductive adhesive 57
Electrically connected to each other by the
The oscillator body 34 is supported and fixed therein (see FIG. 7).

As described above, in the SAW oscillator according to the third embodiment, the SAW resonator 32 is formed on the front surface of the piezoelectric substrate 31, while the IC chip 33 is flip-chip mounted on the rear surface of the piezoelectric substrate 31. I did it. Therefore, the electrical connection distance between the SAW resonator 32 and the IC chip 33 is shortened, so that stray inductance and stray capacitance can be reduced, and electric characteristics such as high-frequency characteristics are improved.

In the SAW oscillator according to the third embodiment, the temperature sensor is provided on the IC chip 33 and the temperature sensor and the SAW resonator 32 are brought close to each other. Accuracy is improved,
Thereby, the temperature compensation of the SAW resonator 32 by the temperature compensation circuit becomes more appropriate.

Further, in the SAW oscillator according to the third embodiment, the IC chip 33 is flip-chip mounted on the back side of the piezoelectric substrate 31, and a conductive adhesive is used when the piezoelectric substrate 31 is mounted in the package 35. By doing so, it is possible to reduce the number of assembling steps, the production cost, and the impact resistance.

In the SAW oscillator according to the third embodiment, the IC chip 33 is mounted by using the back surface of the piezoelectric substrate 31 forming the SAW resonator 32.
The size can be reduced.

Next, a fourth embodiment of the SAW oscillator according to the present invention will be described with reference to FIGS.

The SAW oscillator according to the fourth embodiment has the structure shown in FIG.
And the oscillator main body 34 of the third embodiment shown in FIG. 7 is replaced with an oscillator main body 34A as shown in FIGS. 10 and 11, and this oscillator main body 34A is housed in a package 35 with its back face down and fixed. The upper opening of the package 35 is sealed with a lid 36.

The oscillator body 34A has basically the same structure as the oscillator body 34 of the third embodiment shown in FIGS. 8 and 9, but only the structure on the back side of the piezoelectric substrate 31 is as shown in FIG. Are different. That is, as shown in FIG. 12, conductive patterns 61 to 64 connected to the IC chip 33 are provided on the back surface of the piezoelectric substrate 31, and the conductive patterns 61 to 64 are provided at both ends in the longitudinal direction on the back surface. Are connected to the external input / output terminals 61A to 64A provided at the terminals.

Since the configuration of the other portion on the back side of the oscillator main body 34A is the same as that of FIG. 9, the same portions are denoted by the same reference numerals in FIG.
The configuration on the front side is the same as that of FIG.

Further, in the fourth embodiment, as shown in FIG. 10, a pair of rectangular parallelepiped terminal blocks 65 and 66 are provided at predetermined intervals in the width direction in the package 35, and the terminal blocks 65 are provided. , 66, a plurality of external input / output terminals 67 to
70 are provided. Then, the oscillator main body 34A is housed in the package 35 with its back side facing down, and the external input / output terminals 6 provided on the back surface of the piezoelectric substrate 31 are provided.
1A to 64A and external input / output terminals 67 opposed thereto.
To 70 are electrically connected by a conductive adhesive 57, thereby supporting and fixing the oscillator main body 34A in the package 35 (see FIG. 11).

According to the fourth embodiment, the oscillator body 34A is fixed in the package 35 by the conductive adhesive 57 at four locations (61A to 64A) on both sides of the oscillator body 34A, so that the oscillator body 34A is shock-resistant. Seen from above, it is possible to fix it very stably.

Next, a fifth embodiment of the SAW oscillator according to the present invention will be described with reference to FIG.

The SAW oscillator according to the fifth embodiment has the structure shown in FIG.
The oscillator body 34A according to the fourth embodiment shown in FIG. 2 is replaced with an oscillator body 34B as shown in FIG. That is, as shown in FIG. 12, the oscillator main body 34B is provided with external input / output terminals 71A to 74A only at one end in the length direction on the back surface of the piezoelectric substrate 31, and the external input / output terminals 71A to 74A are provided. Are conductive patterns 71 to 74 provided on the back surface for connection to the IC chip 33.
Is connected to

The oscillator main body 34B thus configured
Are housed in the package 35 similarly to the oscillator main body 34A shown in FIG. 10, but in this case, only four external input / output terminals are provided on the terminal block 66, and the oscillator main body 34B
The external input / output terminals 71A to 74A and the four external input / output terminals facing them are electrically connected by a conductive adhesive, whereby the oscillator body 34B is supported and fixed in the package 35.

Next, a sixth embodiment of the SAW oscillator according to the present invention will be described with reference to FIGS.

The SAW oscillator according to the sixth embodiment has the structure shown in FIG.
And the oscillator body 34 according to the third embodiment shown in FIG.
To an oscillator body 34C as shown in FIGS. 14 and 15.
This oscillator body 34C is housed in a package 35 shown in FIG.

As shown in FIG. 14, the oscillator body 34C includes a pair of comb-shaped electrodes 37 and 38 provided on the surface side of the piezoelectric substrate 31 and a pair of reflectors 39 and 40, and the width of the piezoelectric substrate 31 is adjusted. It is provided in the direction. Further, conductive patterns 81 and 82 for connecting the comb-shaped electrodes 37 and 38 on the front side of the piezoelectric substrate 31 and the IC chip 33 mounted on the back side thereof are formed as shown in FIGS.
The piezoelectric substrate 31 is provided on the front surface, the front surface, and the rear surface thereof in a series.

The structure of the other parts of the sixth embodiment is the same as that of the third embodiment, so that the description thereof will be omitted, and in FIG. 15, the same parts as those of FIG. did.

[0059]

As described above, according to the present invention,
IC chip mounting area of piezoelectric substrate or SA of piezoelectric substrate
The IC chip is mounted on the opposite surface where the W resonator is not formed. For this reason, the electrical connection distance between the SAW resonator and the IC chip is shortened and the stray inductance and stray capacitance can be reduced, so that the electrical characteristics such as high-frequency characteristics are improved.

In the present invention, when a temperature sensor and a temperature compensation circuit are provided on an IC chip, the temperature sensor and the SAW resonator can be brought close to each other, so that the detection accuracy of the SAW resonator by the temperature sensor is improved. This makes temperature compensation of the SAW resonator by the temperature compensation circuit more appropriate.

Further, according to the present invention, the IC chip is flip-chip mounted on the IC chip mounting area of the piezoelectric substrate of the piezoelectric substrate or on the opposite surface of the piezoelectric substrate on which the SAW resonator is not formed, and the package of the piezoelectric substrate is mounted. As we used conductive adhesive when mounting inside,
It can reduce the number of assembly steps, the production cost, and the impact resistance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall configuration of a first embodiment of a SAW oscillator according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view of an oscillator main body according to the first embodiment.

FIG. 4 is a diagram illustrating a mounted state of an IC chip according to the first embodiment.

FIG. 5 is a perspective view of an oscillator main body according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing the overall configuration of a third embodiment of the present invention.

FIG. 7 is a sectional view taken along line BB of FIG. 6;

FIG. 8 is a front perspective view of an oscillator body according to a third embodiment.

FIG. 9 is a perspective view of the back side of the oscillator main body.

FIG. 10 is a perspective view showing the overall configuration of a fourth embodiment of the present invention.

FIG. 11 is a sectional view taken along line CC of FIG. 10;

FIG. 12 is a perspective view of the back side of an oscillator main body according to a fourth embodiment.

FIG. 13 is a perspective view of a back side of an oscillator main body according to a fifth embodiment of the present invention.

FIG. 14 is a front perspective view of an oscillator body according to a sixth embodiment of the present invention.

FIG. 15 is a perspective view of the back side of the oscillator main body.

[Explanation of symbols]

 1, 31 Piezoelectric substrate 1A IC chip mounting area 1B SAW resonator forming area 2, 32 SAW resonator 3, 33 IC chip 4, 34 Oscillator main body 5, 35 Package 6, 36 Cover 7, 8, 37, 38 Comb-shaped electrode ( Blind electrodes) 9, 10, 39, 40 Reflectors 11-16, 41-46 Conductive patterns 11A-16A, 41A-46A External input / output terminals 17 Bumps (protruding electrodes) 20-23 External input / output terminals 24 Conductive adhesive 25, 26 terminal block

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J079 AA06 BA02 BA43 BA44 BA49 CB01 FA01 HA04 HA06 HA08 HA09 HA25 HA28 HA29 5J097 AA21 AA31 AA33 AA34 BB01 KK10 LL08

Claims (8)

[Claims] 1. A SAW oscillator comprising: a SAW resonator formed by providing at least a comb-shaped electrode on a piezoelectric substrate; and an IC chip in which an oscillation circuit for driving the SAW resonator is integrated. Is a SAW for forming the SAW resonator.
IC for mounting the IC chip in addition to the resonator forming area
A SAW oscillator comprising a chip mounting area, wherein the IC chip is mounted in the IC chip mounting area. 2. The SAW according to claim 1, wherein the mounting of the IC chip is flip-chip mounting.
Oscillator. 3. The piezoelectric substrate on which the SAW resonator is formed and the IC chip is mounted is housed in a package, and the piezoelectric substrate is fixed in the package in the IC chip mounting area. 3. The SAW oscillator according to claim 1, wherein the external input / output terminal is connected to an external input / output terminal provided in the package by a conductive adhesive. 4. The IC chip includes, in addition to the oscillation circuit, a temperature sensor for detecting a temperature of the SAW resonator, and a temperature compensation circuit for performing temperature compensation of the SAW resonator based on a temperature detected by the temperature sensor. The SAW oscillator according to claim 1, wherein the SAW oscillator includes: 5. A SAW oscillator comprising: a SAW resonator formed by providing at least a comb-shaped electrode on a piezoelectric substrate; and an IC chip in which an oscillation circuit for driving the SAW resonator is integrated. A surface opposite to the surface on which the comb-shaped electrodes are provided is an IC chip mounting area for mounting the IC chip, and the IC chip is mounted in the IC chip mounting area. 6. The SAW according to claim 5, wherein the mounting of the IC chip is flip-chip mounting.
Oscillator. 7. The piezoelectric substrate on which the SAW resonator is formed and the IC chip is mounted is housed in a package, and the piezoelectric substrate is fixed in the package in the IC chip mounting area. 7. The SAW oscillator according to claim 5, wherein the external input / output terminal is connected to an external input / output terminal provided in the package by a conductive adhesive. 8. The IC chip includes, in addition to the oscillation circuit, a temperature sensor for detecting a temperature of the SAW resonator, and a temperature compensation circuit for performing temperature compensation of the SAW resonator based on a temperature detected by the temperature sensor. 8. The SAW oscillator according to claim 5, wherein the SAW oscillator includes: