JP3735418B2 - Surface acoustic wave device and communication apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface acoustic wave (SAW) device suitable for application to, for example, a filter circuit and a resonance circuit, and a communication apparatus using the same.
[0002]
[Prior art]
In communication apparatuses such as cellular phones, surface acoustic wave devices are used as bandpass filters, for example. This surface acoustic wave device has a configuration in which a surface acoustic wave element substrate on which a surface acoustic wave circuit is formed is hermetically sealed in a package in order to reduce a change in performance over time.
[0003]
FIG. 7 shows a front configuration of a face surface of a general rectangular flip chip type surface acoustic wave element substrate 1 on which a SAW filter circuit is formed.
[0004]
This surface acoustic wave element substrate 1 has an input pad electrode 2, an output pad electrode 3 and a ground pad electrode 4 each formed with a bump, and each pad electrode 2 to 4 is formed with a known comb electrode. Has been.
[0005]
FIG. 8 shows a front configuration of a package 6 having a recess 5 in which the face surface of the surface acoustic wave element substrate 1 in the example of FIG. 7 is housed downward. In this package 6, the bottom surface of the recess 5 is a die attach surface 7. On the die attach surface 7, input / output die pad electrodes 2a, 3a are formed at positions where the input / output pad electrodes 2, 3 face each other. A ground die pad electrode 4a is formed at a portion other than the input / output die pad electrodes 2a and 3a.
[0006]
FIG. 9 shows a rear front configuration of the footprint surface 9 (surface mounted on a print of another mother board or the like) 9 of the package 6. On the footprint surface 9, an input terminal pattern electrode 2b, an output terminal pattern electrode 3b, and a ground pattern electrode 4b are formed. The input terminal pattern electrode 2b and the input die pad electrode 2a formed on the die attach surface 7 are electrically connected by through-hole processing or castellation processing. Similarly, the output terminal pattern electrode 3b and the output die pad electrode 3a, and the ground pattern electrode 4b and the ground die pad electrode 4a are electrically connected by through-hole processing or castellation processing.
[0007]
When the surface acoustic wave device is manufactured, the flip chip type surface acoustic wave element substrate 1 shown in FIG. 7 is faced downward and inserted into the recess 5 of the package 6 shown in FIG. As a result, the input / output die pad electrodes 2 a and 3 a and the ground die pad electrode 4 a of the package 6 are automatically aligned with respect to the input and output pad electrodes 2 and 3 and the ground pad electrode 4 of the surface acoustic wave element substrate 1.
[0008]
Then, in a state where the surface acoustic wave element substrate 1 is housed in the package 6, a load and ultrasonic vibration are applied from the back surface of the surface acoustic wave element substrate 1 while applying heat to the footprint surface 9 of the package 6. The input / output die pad electrodes 2 a, 3 a and the ground die pad electrode 4 a of the package 6 are joined to and electrically connected to the input / output pad electrodes 2, 3 and the ground pad electrode 4 of the surface acoustic wave element substrate 1.
[0009]
Thereafter, as shown in the schematic cross-sectional view of FIG. 10, a cap (lid member) 10 is placed so as to cover the concave portion 5 of the package 6, and the concave portion 5 in which the surface acoustic wave element substrate 1 is accommodated is evacuated. Alternatively, it is filled with nitrogen to be airtight, and the lid member 10 is fixed with solder, Au—Sn, an adhesive, or the like. Thereby, the surface acoustic wave device 110 is completed.
[0010]
Note that the package 6 constituting the surface acoustic wave device 110 in FIG. 10 is made up of a ceramic substrate 6A and a ceramic frame 6B, and has a pattern on the die attach surface 7 and the footprint surface 9 on the ceramic substrate 6A. After the through hole or castellation is formed, the ceramic frame 6B is fixed to the surface around the die attach surface 7.
[0011]
[Problems to be solved by the invention]
By the way, in a surface acoustic wave device, a surface acoustic wave element substrate having two functions, for example, two surface acoustic wave circuits (surface acoustic wave element circuits) having different center frequencies is mounted. There is a case.
[0012]
FIG. 11 shows a configuration example of a surface acoustic wave element substrate 13 in which two-surface surface acoustic wave filters 11 and 12 are formed on the face surface. One surface acoustic wave filter 11 has an input pad electrode 21 and an output pad electrode 22, and the other surface acoustic wave filter 12 has an input pad electrode 23 and an output pad electrode 24. A ground pad electrode 25 is also formed on the face surface.
[0013]
FIG. 12 shows a front configuration of a package 16 having a recess 15 in which the face surface of the surface acoustic wave element substrate 13 in the example of FIG. In the package 16, the bottom surface of the recess 15 is a die attach surface 17, and input die pad electrodes 21 a and 23 a are formed on the die attach surface 17 at positions opposite to the input pad electrodes 21 and 23, and output is performed. Output die pad electrodes 22a and 24a are formed at positions opposite to the pad electrodes 22 and 24, and ground die pad electrodes 25a are formed at portions other than these.
[0014]
FIG. 13 shows a rear front configuration of the footprint surface 19 of the package 16 (surface mounted on a print of another motherboard or the like) 19. On the footprint surface 19, input terminal pattern electrodes 21b and 23b, output terminal pattern electrodes 22b and 24b, and a ground pattern electrode 25b are formed. The input terminal pattern electrode 21b and the input die pad electrode 21a formed on the die attach surface 17, the output terminal pattern electrode 22b and the output die pad electrode 22a formed on the die attach surface 17, the input terminal pattern electrode 23b and the die The input die pad electrode 23a and the output terminal pattern electrode 24b formed on the touch surface 17 and the output die pad electrode 24a formed on the die attach surface 17 are electrically connected by through-hole processing or castellation processing, respectively. It has been taken.
[0015]
A surface acoustic wave device includes a surface acoustic wave element substrate 13 having surface acoustic wave filters 11 and 12 of two circuits formed on the face surface in the example of FIG. 11 and a package 16 shown in FIGS. 12 (front) and 13 (back). 11 is inserted into the recess 15 of the package 16 with the face surface of the flip chip type surface acoustic wave element substrate 13 shown in FIG.
[0016]
However, when the surface acoustic wave element substrate 13 is inserted into the package 16 and rotated by 180 °, there is a problem that the positions of the surface acoustic wave filter 11 and the surface acoustic wave filter 12 are reversed.
[0017]
Further, when the electrical characteristics of the manufactured surface acoustic wave device are inspected, the positions of the surface acoustic wave filter 11 and the surface acoustic wave filter 12 are reversed even when the package 16 is rotated 180 °. There was a problem.
[0018]
Therefore, in order to avoid such an inconvenience of the reversal of position, there is a complexity that it is necessary to manage the directionality of both the surface acoustic wave element substrate 13 and the package 16.
[0019]
This management of directionality is a cumbersome task in the manufacturing and assembly process of the surface acoustic wave device that the steps of recognizing and aligning the directionality of both the surface acoustic wave element substrate 13 and the package 16 are indispensable operations. Generate.
[0020]
Further, even in the electrical characteristic inspection process after the manufacturing and assembling process, there is an inconvenience that alignment in consideration of the directionality of the package 16 is required.
[0021]
After all, it takes time to manufacture and inspect the surface acoustic wave device, and the cost of the surface acoustic wave device increases.
[0022]
The present invention has been made in consideration of such problems, and a surface acoustic wave device is obtained by accommodating a rectangular flip chip type surface acoustic wave element substrate in which two surface acoustic wave circuits are formed in a package. It is an object of the present invention to provide a surface acoustic wave device that can be manufactured and inspected without considering the directionality of the surface acoustic wave element substrate and the package when manufactured and inspected, and a communication apparatus using the surface acoustic wave device.
[0023]
[Means for Solving the Problems]
1 to 3, for example, a rectangular flip chip type in which two surface acoustic wave circuits 41 and 42 each having input / output pad electrodes 51 to 54 are formed on a face surface 40 are formed. A surface acoustic wave element substrate 44;
The surface has a rectangular recess 115 for accommodating the surface acoustic wave element substrate, and input / output die pad electrodes 51a to 54a are formed at positions facing the input / output pad electrode on the bottom surface 117 of the recess, A rectangular package 116 in which input / output terminal pattern electrodes 51b to 54b electrically connected to the input / output die pad electrode are formed on the back surface;
In a surface acoustic wave device comprising:
The input / output pad electrodes of each of the two circuits formed on the surface acoustic wave element substrate are arranged substantially symmetrically with respect to the center P of the rectangular shape of the flip chip, and the back surface of the rectangular package. The input / output terminal pattern electrodes of each of the two circuits formed in the above are arranged substantially symmetrically with respect to the center Q of the rectangular shape of the package.
[0024]
According to the present invention, the positions of the input / output pad electrodes of each circuit of the surface acoustic wave circuit of two circuits are formed substantially symmetrical with respect to the center of the rectangular flip chip type surface acoustic wave element substrate, Similarly, the position of the electrode on the package side is substantially point-symmetric with respect to the center of the rectangular shape of the package, so that it is not necessary to consider the directionality in the manufacturing / assembling process and the inspection process.
[0025]
In this case, the size of the surface acoustic wave element substrate can be made small by employing a cross line for the wiring on the face surface of the surface acoustic wave element substrate.
[0026]
In addition, by using the surface acoustic wave device manufactured in this way for a communication device, the communication device can be reduced in cost and size.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings to be referred to below, the same reference numerals are assigned to the components corresponding to those shown in FIGS. 7 to 13 and the detailed description thereof is omitted. Moreover, in order to avoid the troublesomeness to repeat the drawings, description will be made with reference to those drawings as necessary.
[0028]
FIG. 1 shows a configuration example of a surface acoustic wave element substrate 44 in which surface acoustic wave filters (SAW filters) 41 and 42 as examples of two surface acoustic wave circuits are formed on a face surface 40 of a piezoelectric substrate. Show. The surface of this surface acoustic wave element substrate 44 has a rectangular flip chip type configuration. This surface acoustic wave element substrate 44 has input pad electrodes 51 and 53, output pad electrodes 52 and 54, and ground pad electrodes 55 and 56 each having a bump formed thereon. A known comb electrode is formed.
[0029]
More specifically, one surface acoustic wave filter 41 includes an input pad electrode 51 and a wiring pattern in which one end portion is connected to the input pad electrode 51 and the other end portion is connected to an input end of the comb-shaped electrode portion 61. 62, a wiring pattern 63 having one end connected to the output end of the comb electrode portion 61 and the other end connected to the output pad electrode 52, and the output pad electrode 52. The other surface acoustic wave filter 42 includes an input pad electrode 53, a wiring pattern 66 having one end connected to the input pad electrode 53 and the other end connected to the input end of the comb-shaped electrode portion 65, and the comb-shaped electrode portion. The wiring pattern 67 has one end connected to the output end 65 and the other end connected to the output pad electrode 54.
[0030]
In the surface acoustic wave element substrate 44 of FIG. 1, the positions of the input pad electrode 51 and the output pad electrode 52 constituting one surface acoustic wave filter 41 are determined using the wiring pattern 62 and the wiring pattern 66. The input pad electrode 53 and the output pad electrode 54 constituting the other surface acoustic wave filter 42 are formed at substantially diagonal positions symmetrical with respect to the center P of the rectangular shape of the surface acoustic wave element substrate 44. The position is formed at a substantially diagonal position that is substantially point-symmetric with respect to the rectangular center P of the surface acoustic wave element substrate 44.
[0031]
In this case, the package shown in FIGS. 12 and 13 can be used as the package on which the surface acoustic wave element substrate 44 of FIG. 1 is mounted. Since the correspondence relationship between the electrodes on the package and the electrodes on the surface acoustic wave element substrate 44 in the example of FIG. 1 is different, FIGS.
[0032]
That is, FIG. 2 shows a front configuration of a package 116 having a recess 115 in which the face surface 40 of the surface acoustic wave element substrate 44 of FIG. In this package 116, the concave portion 115 has a similar shape slightly larger than the rectangular shape of the surface acoustic wave element substrate 44. The bottom surface of the recess 115 is a die attach surface 117, and an input die pad electrode 51 a is formed on the die attach surface 117 at a position facing the input pad electrode 51 of one surface acoustic wave filter 41, and an output pad electrode An output die pad electrode 52 a is formed at a position facing 52. On the die attach surface 117, an input die pad electrode 53a is formed at a position facing the input pad electrode 53 of the other surface acoustic wave filter 42, and an output die pad electrode 54a is formed at a position facing the output pad electrode 54. Is formed. Further, as a result, ground die pad electrodes 155a are formed on portions of the die attach surface 117 excluding the electrode portions at the four corners.
[0033]
FIG. 3 shows a rear front configuration of the footprint 116 of the package 116 (surface mounted on a printed wiring board such as another mother board) 119. On the footprint surface 119, input terminal pattern electrodes 51b and 53b, output terminal pattern electrodes 52b and 54b, and a ground pattern electrode 155b are formed.
[0034]
The input terminal pattern electrode 51 b and the input die pad electrode 51 a on the die attach surface 117, the output terminal pattern electrode 52 b and the output die pad electrode 52 a on the die attach surface 117, and the input terminal pattern electrode 53 b and the die attach surface 117. The input die pad electrode 53a is further electrically connected to the output terminal pattern electrode 54b and the output die pad electrode 54a of the die attach surface 117 by through-hole processing or castellation processing, respectively. Similarly, the ground pattern electrode 155b and the ground die pad electrode 155a of the die attach surface 117 are electrically connected by through-hole processing or castellation processing.
[0035]
When a surface acoustic wave device having airtightness is manufactured, as described with reference to FIG. 10, the surface of the surface acoustic wave element substrate 44 on which the two-surface surface acoustic wave filters 41 and 42 are formed. After the surface 40 is faced down and inserted into the recess 115 of the package 116 and the opposing electrodes are joined, the cap 10 (see FIG. 10) is fixed.
[0036]
In this case, the respective electrodes formed on the die attach surface 117 and the footprint surface 119 of the package 116 are formed symmetrically with respect to the vertical and horizontal center lines of the rectangular shape, and are formed on the surface acoustic wave element substrate 44. The input pad electrode 51 and the output pad electrode 52 are formed substantially symmetrically on one diagonal line with respect to the rectangular center P, and the input pad electrode 53 and the output pad electrode 54 are formed with respect to the rectangular center P. Since it is formed substantially point-symmetrically on the other diagonal, each electrode is automatically aligned.
[0037]
As a result, even if the surface acoustic wave element substrate 44 is rotated by 180 ° and inserted, one surface acoustic wave filter 41 is always connected between the input / output terminal pattern electrodes 51b and 52b of the footprint surface 119 of the package 116. Therefore, the remaining surface acoustic wave filter 42 is always connected between the input / output terminal pattern electrodes 53b and 54b, and there is no need to consider the directionality when the surface acoustic wave device is manufactured and assembled. Similarly, it is not necessary to consider directionality at the time of inspection.
[0038]
In practice, when the input / output impedances of the surface acoustic wave filters 41 and 42 are the same, both the surface acoustic wave filters 41 and 42 are circuits composed of passive elements, so that the input / output is inverted by 180 °. Even if the terminal is used instead, it is possible to make a circuit having the same pass characteristic, and there is no need to consider the directionality.
[0039]
However, when the input and output impedances are different, for example, when the input impedance is 50 ohms and the output impedance is 75 ohms or the like, first, when performing an electrical inspection using a network analyzer or the like, check the input impedance, The input / output end is specified and the surface of the cap 10 (see FIG. 10) is marked. For the marking, for example, a black dot is attached to a corner near the input end. Alternatively, the characters indicating the input end and the output end at the same time as the characters such as the model are recorded by, for example, a laser. In this way, it is possible to easily determine the directionality by visual or using an imaging device such as a CCD camera at the time of electrical inspection as the final process. The effect is achieved that there is no need to consider at all. If the directionality is confirmed and found to be 180 ° different, the surface acoustic wave device itself has a point-symmetric configuration, so the surface acoustic wave device is placed on the rotary table, It is sufficient to rotate 180 ° around the center P. Therefore, the surface acoustic wave device of this embodiment is suitable for automation of manufacturing and assembly and automation of electrical inspection.
[0040]
FIG. 4 shows the structure of a surface acoustic wave element substrate 144 according to another embodiment of the present invention. In the example of FIG. 4, the same reference numerals are assigned to the components corresponding to those of FIG. 1, and detailed description thereof is omitted. Also in this surface acoustic wave element substrate 144, the positions of the input pad electrode 51 and the output pad electrode 52 constituting one of the surface acoustic wave filters 41 are located on diagonal lines that are substantially point symmetric with respect to the center P of the rectangular shape. In addition, the positions of the input pad electrode 53 and the output pad electrode 54 constituting the other surface acoustic wave filter 42 are formed at diagonal positions that are substantially point-symmetric with respect to the center P of the rectangular shape.
[0041]
In this case, as can be understood from FIG. 4, in the surface acoustic wave element substrate 144, the wiring pattern 162 connecting the input pad electrode 51 and the input end of the comb-shaped electrode portion 61, the input pad electrode 53 and the comb-shaped An intersecting line portion (crossover portion) 170 is provided between the wiring pattern 166 and the input end of the electrode portion 65. By providing the intersecting line portion 170, the flexibility of the wiring is increased, and the rectangular shape can be made smaller than the surface acoustic wave element substrate 44 of FIG. As a result, the surface acoustic wave device can be reduced in size, and the communication apparatus using the surface acoustic wave device can be reduced in size and weight. As a communication device, for example, in a cellular phone, downsizing and weight reduction in units of 1 cc and 1 g are important features.
[0042]
5 and 6 each show a schematic cross section according to a configuration example of the intersecting line portion 170. FIG. In the crossing line portion 170 in the example of FIG. 5, a straddling line (stranding line) 171 is formed between the wiring patterns 162 and 162 by a gold wire or an aluminum wire so as to straddle the wiring pattern 166. As shown in FIG. 5, the space 171 and the wiring pattern 166 may be air 172, a so-called air bridge, or may be an insulator 174 such as SiO _{2 as} shown in FIG. In the case of the insulator 174, the mechanical strength between the straddle 171 and the wiring pattern 166 can be increased as compared with the case of the air 172. Further, in the case of air 172, electrical coupling between the straddle 171 and the wiring pattern 166 can be reduced as compared with the case of the insulator 174.
[0043]
Note that the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.
[0044]
【The invention's effect】
As described above, according to the present invention, the positions of the input / output pad electrodes of each circuit of the two surface acoustic wave circuits are substantially the same as the center of the rectangular flip chip type surface acoustic wave element substrate. Similarly, the electrode positions on the package side are formed substantially point symmetrically with respect to the center of the rectangular shape of the package.
[0045]
For this reason, the effect that it can manufacture correctly, without considering directionality in the manufacture assembly process of a surface acoustic wave device, and an inspection can be implemented without considering directionality in an inspection process is achieved.
[0046]
Therefore, the manufacturing process can be simplified, and as a result, a derivative effect that the cost of the surface acoustic wave device can be reduced is also achieved.
[0047]
By adopting cross lines for the wiring on the face surface of the surface acoustic wave element substrate, the size of the surface acoustic wave element substrate can be made small. As a result, the surface acoustic wave device is It can be downsized.
[0048]
Thus, it is possible to achieve cost reduction, size reduction, and weight reduction of a communication device such as a mobile phone using such a low-cost and small surface acoustic wave device.
[Brief description of the drawings]
FIG. 1 is a front view showing a configuration of a surface acoustic wave element substrate on which two surface acoustic wave circuits according to an embodiment of the present invention are formed.
2 is a front view showing a configuration of a package having a die attach surface on which the surface acoustic wave element substrate of FIG. 1 is mounted face down. FIG.
FIG. 3 is a rear view of the package of the example of FIG. 2;
FIG. 4 is a front view showing a configuration of a surface acoustic wave element substrate according to another embodiment of the present invention.
5 is a schematic cross-sectional view for explaining a configuration of a crossing line portion on the surface acoustic wave element substrate in the example of FIG. 4; FIG.
6 is a schematic cross-sectional view for explaining another configuration of the crossing line portion on the surface acoustic wave element substrate in the example of FIG. 4; FIG.
FIG. 7 is a front view showing a configuration of a surface acoustic wave element substrate on which a general surface acoustic wave filter circuit of one circuit is formed.
8 is a front view showing a configuration of a package on which the surface acoustic wave element substrate of the example of FIG. 7 is mounted. FIG.
9 is a rear view showing a configuration of a package on which the surface acoustic wave element substrate of the example of FIG. 7 is mounted. FIG.
FIG. 10 is a schematic cross-sectional view showing a configuration of a surface acoustic wave device in general.
FIG. 11 is a front view showing a configuration of a conventional surface acoustic wave element substrate in which two surface acoustic wave circuits are formed.
12 is a front view showing a configuration of a package on which the surface acoustic wave element substrate of the example of FIG. 11 is mounted. FIG.
13 is a rear view showing a configuration of a package to which the surface acoustic wave element substrate of the example of FIG. 11 is mounted. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 44, 144 ... Surface acoustic wave element substrate 6 ... Package 7, 17, 117 ... Die attach surface 9, 19, 119 ... Footprint surface 10 ... Cap 110 ... Surface acoustic wave device 40 ... Face surface 41, 42 ... Elasticity Surface wave circuit 51, 53 ... Input pad electrode 52, 54 ... Output pad electrode 55, 56 ... Ground pad electrode 61, 65 ... Comb electrode portion 62, 63, 66, 67, 162, 166 ... Wiring pattern 170 ... Crossing line portion P, Q ... center

Claims (4)

A rectangular flip-chip type surface acoustic wave element substrate in which two surface acoustic wave circuits each having input / output pad electrodes on the face surface are formed;
The surface has a rectangular recess for accommodating the surface acoustic wave element substrate, and an input / output die pad electrode is formed at a position opposite to the input / output pad electrode on the bottom surface of the recess, and the input A rectangular package in which an input / output terminal pattern electrode electrically connected to the output die pad electrode is formed;
In a surface acoustic wave device comprising:
The input / output pad electrodes of each of the two circuits formed on the surface acoustic wave element substrate are arranged substantially symmetrical with respect to the center of the rectangular shape of the flip chip,
An elastic surface characterized in that input / output terminal pattern electrodes of each of the two circuits formed on the back surface of the rectangular package are arranged substantially symmetrically with respect to the center of the rectangular shape of the package. Wave device. 2. The surface acoustic wave device according to claim 1, wherein a crossing line is used for the wiring on the face surface of the surface acoustic wave element substrate. A rectangular flip-chip type surface acoustic wave element substrate in which two surface acoustic wave circuits each having input / output pad electrodes on the face surface are formed;
The surface has a rectangular recess for accommodating the surface acoustic wave element substrate, and an input / output die pad electrode is formed at a position opposite to the input / output pad electrode on the bottom surface of the recess, and the input A rectangular package in which an input / output terminal pattern electrode electrically connected to the output die pad electrode is formed;
In a communication apparatus using a surface acoustic wave device comprising:
The input / output pad electrodes of each of the two circuits formed on the surface acoustic wave element substrate are arranged substantially symmetrical with respect to the center of the rectangular shape of the flip chip,
The input / output terminal pattern electrode of each of the two circuits formed on the back surface of the rectangular package is arranged substantially point-symmetrically with respect to the center of the rectangular shape of the package. . 4. The communication apparatus according to claim 3, wherein a crossing line is used for the wiring on the face surface of the surface acoustic wave element substrate.

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