JP3487414B2 - Surface acoustic wave filter device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave filter device, and more particularly to a surface acoustic wave filter device applied to a filter of a high frequency circuit of a mobile phone. Current,
Surface acoustic wave filter using surface acoustic waves (Surface Ac
The oustic wave (hereinafter referred to as SAW filter) is widely used in the filter circuit of the high frequency part of the mobile phone. This SAW filter functions so as to pass a necessary signal and attenuate and suppress an unnecessary signal to be excluded. In order to improve the performance of the mobile phone, in the SAW filter, firstly, the attenuation outside the pass band is increased in the vicinity of the pass band of, for example, about 900 MHz, and secondly, in the pass band. It is desired to increase the amount of attenuation in a high frequency band of several GHz which is considerably higher. In the high frequency part of a mobile phone, a plurality of SAW filters such as an antenna duplexer, an interstage filter and an IF filter are used. Since the pass bands of the SAW filters are different, interference occurs between the SAW filters and the frequency is several GHz. It is possible that higher harmonics are generated. It is necessary to increase the amount of attenuation even in a high frequency band of several GHz, which is considerably higher than the pass band, in order to suppress and attenuate this unnecessary harmonic noise and improve the characteristics of the high frequency part of the mobile phone. is there.

[0002] A SAW filter usually has a structure in which a surface acoustic wave filter body having a reflector and a comb-shaped electrode formed on a piezoelectric substrate is mounted on a package body. SAW
The filter is mounted on the printed board by using the pad of the package body. Here, for convenience of explanation, the reflector and the comb-shaped electrode formed on the piezoelectric substrate will be described.

FIG. 1A shows an element 10 of a SAW filter which is a dual mode type and a single type having two modes. The input side comb-shaped electrode pair 11 is arranged in the center, and the output side comb-shaped electrode pairs 12 and 13 are arranged on both sides thereof,
The reflectors 14 and 15 are provided outside the comb electrodes 12 and 13 on the output side.
Are arranged. The input side comb-shaped electrode 11 has an input terminal 20.
Primary side comb-shaped electrode 11-1 and ground 21 connected to
And the secondary side comb-shaped electrode 11-2 connected to. One output-side comb-shaped electrode pair 12 includes a primary-side comb-shaped electrode 12-1 connected to the output terminal 22 and a secondary-side comb-shaped electrode 12-2 connected to the ground 23. Another output-side comb-shaped electrode pair 13 is connected to the output terminal 22 described above.
2 connected to the next comb electrode 13-1 and the ground 24
It is composed of the next comb electrode 13-2.

In such a dual mode SAW filter,
As shown in FIG. 1 (B), a first-order mode having a frequency f1 formed between the reflectors 14 and 15 and a frequency f3.
And the frequency f as shown in FIG.
A pass band characteristic having a pass band between 1 and f3 is realized. However, FIG. 1B shows the energy distribution of the surface acoustic wave in the structure of FIG.

FIG. 3 shows a double mode cascade type SAW filter element 40 in which two elements 10 of the SAW filter of FIG. 1A are cascade-connected in series. In the first-stage single-type element 10-1, the input side comb-shaped electrode pair 11 is arranged in the center, and the output side comb-shaped electrode pairs 12 and 13 are arranged on both sides thereof,
The reflectors 14 and 15 are provided outside the comb electrodes 12 and 13 on the output side.
Are arranged. Second stage single type element 10
-2, the output side comb-shaped electrode pair 41 is arranged in the center, the input side comb-shaped electrode pairs 42 and 43 are arranged on both sides thereof, and the reflectors 44 and 45 are arranged outside the input side comb-shaped electrode pairs 42 and 43. Has been done. The primary-side comb-shaped electrode 11-1 of the input-side comb-shaped electrode pair 11 of the first-stage single-type element 10-1 is connected to the input terminal 20. The primary-side comb-shaped electrode 4 of the output-side comb-shaped electrode pair 41 of the second-stage single-type element 10-2
1-1 is connected to the output terminal 46. The primary-side comb-shaped electrode 12-1 of the output-side comb-shaped electrode pair 12 on the first stage side and the primary-side comb-shaped electrode 42-1 of the input-side comb-shaped electrode pair 42 on the second-stage side are connected. The primary side comb-shaped electrode 13-1 of the output side comb-shaped electrode pair 13 on the first stage side and the input side comb-shaped electrode pair 43 of the second stage side.
Is connected to the primary side comb-shaped electrode 43-1. The secondary-side comb-shaped electrode 11-2 of the input-side comb-shaped electrode pair 11 on the first stage side is the ground 21, and the secondary-side comb-shaped electrodes 12-2 and 13-2 of the output-side comb-shaped electrode pairs 12 and 13 are ground 23, respectively. , 24
The secondary comb-shaped electrode 41-2 of the output-side comb-shaped electrode pair 41 on the second stage side is the ground 47, and the input-side comb-shaped electrode pair 42, 4
The secondary comb-shaped electrodes 42-2 and 43-2 of No. 3 are connected to the grounds 48 and 49, respectively.

This SAW filter has better frequency characteristics than the SAW filter of FIG.

[0007]

2. Description of the Related Art FIGS. 4, 5A to 5C and 6 show
1 schematically shows a conventional SAW filter package device 60. 5A is a plan view, FIG. 5B is a side view, and FIG. 5C is a bottom view. The SAW filter package device 60 has a structure in which the surface acoustic wave filter body 101 shown in FIG. 12 is mounted inside a box-shaped package body 62 and sealed by a cap 63.

The box-shaped package body 62 has a bottom plate 64.
And a rectangular frame 65 fixed to this. The bottom plate 64 has a ground pad 70, an input pad 71, and an output pad 72 on the upper surface, as also shown in FIG.
Ground foot pattern 7 at one diagonal position on the bottom surface
3, 74, and has an input foot pattern 75 and an output foot pattern 76 at different diagonal positions. Also, the via pad 77 and the ground foot pattern 7 are provided by the via 77.
3 is connected to the ground pad 70 by the via 78.
And the ground foot pattern 74 are connected, and the via 79
The input pad 71 and the input foot pattern 75 are connected by, and the output pad 72 and the output foot pattern 76 are connected by the via 80. Ground pad 7
0 has a substantially H shape and is connected as a whole. The surface acoustic wave filter body 101 includes a pad 70 corresponding to each terminal,
71 and 73 are connected and mounted.

In the SAW filter package device 60 before being mounted on the printed circuit board, all the ground terminals 21A of the surface acoustic wave filter body 101,
23A, 47A, and 48A (see FIG. 12) are commonly connected to the ground pad 70. Figure 1 (A)
Referring to, the structure has a structure in which the grounds 23, 24 and the ground 21 are connected.

The ground pad 70 and the cap 63 are connected by the vias 81 and 82 inside the frame 65. S
The AW filter package device 60 is mounted on the printed board by soldering the ground foot patterns 73, 74, the input foot pattern 75, and the output foot pattern 76 on the bottom surface to the corresponding pads on the printed board.

When the pass characteristic of the SAW filter package device 60 was measured with the SAW filter package device 60 mounted on the printed circuit board, it was 950.
Figure 1 shows the target pass band around MHz.
The pass characteristic shown by the line Ia in FIG.
Regarding the frequency bands up to, the pass characteristic shown by the line IIa in FIG. 14 was obtained.

[0012]

SAW filter device 6
As for 0, looking at the passage characteristic shown by the line Ia in FIG.
The amount of attenuation outside the pass band remains at around -50 dB,
In order to improve the performance of mobile phones, it is required to further increase the amount of attenuation. Looking at the pass characteristic shown by the line IIa in FIG. 14, the attenuation amount in the high frequency band of about several GHz remains at about −30 dB, and it is required to further increase the attenuation amount in order to improve the performance of the mobile phone. Has been.

Here, the reason why the increase in the attenuation amount is limited is that the SAW filter package device 60 has a common ground, so that the surface acoustic wave filter body 101 is provided.
It is considered that this is because the impedance of the SAW filter package device 60 interferes with the impedance of the package body 62. In other words, it is considered that there is an extremely small potential difference between the ground potential of the input side comb-shaped electrode pair and the ground potential of the output side comb-shaped electrode pair of the surface acoustic wave filter body. It is considered that the cause is interference between the ground potentials.

Therefore, an object of the present invention is to provide a surface acoustic wave filter device which solves the above problems based on the above idea.

[0015]

According to a first aspect of the present invention, there is provided a piezoelectric substrate, a surface acoustic wave filter circuit formed on the piezoelectric substrate, the surface acoustic wave filter circuit having a plurality of comb-shaped electrode pairs, and a space. It has an input pad, an output pad, and a first ground pad and a second ground pad which are separated from each other, and the piezoelectric substrate is flip-chip bonded together with the surface acoustic wave filter circuit in the space. The package main body housed in a closed state and the package main body so as to cover the space .
One of the second ground pad and the second ground pad
Do not twist the conductive cap that is electrically connected to the
The surface acoustic wave filter circuit is mounted on the piezoelectric substrate.
A first comb-shaped electrode formed and connected to the input terminal
A first comb-shaped electrode pair including a pole and a second comb-shaped electrode;
Formed on the piezoelectric substrate and connected to the output terminal
A second comb-shaped electrode and a fourth comb-shaped electrode
And a pair of comb-shaped electrodes,
Is connected to the input pad, and the output terminal is the output
Connected to a pad, and the second comb-shaped electrode is connected to the first group.
Connected to a land pad, and the fourth comb-shaped electrode is
Connected to the second ground pad, the package body
Mounted on the first ground pad and the second ground pad.
The land pad is configured to be connected through a certain degree of impedance capable of suppressing interference between the potential of the first ground pad and the potential of the second ground pad. It is a thing.

It is considered that there is a very small potential difference between the ground potential for the input side comb electrode pair and the ground potential for the output side comb electrode pair. When the ground of the package body is separated and separated into the ground to which the ground for the input side comb-shaped electrode pair of the surface acoustic wave filter body is connected and the ground to which the ground for the output side comb-shaped electrode pair is connected, No interference occurs between the ground potential of the comb-shaped electrode pair and the ground potential of the output-side comb-shaped electrode pair, and the amount of attenuation outside the pass band is improved by the amount that does not cause interference.

The cap has a first ground pad and a second ground pad.
The configuration in which the cap is electrically connected to one of the ground pads improves the amount of attenuation outside the pass band as compared with the configuration in which the cap is not electrically connected to the ground pad. The structure in which the cap is electrically connected to one of the first ground pad and the second ground pad has a surface acoustic wave filter circuit that is different from the structure in which the cap is not electrically connected to the ground pad. Is effectively shielded against the electromagnetic wave, and the surface acoustic wave filter circuit is effectively suppressed from being affected by an external circuit device.

[0018] The invention according to claim 2, in claim 1, the upper
The impedance described above is formed on the package body.
It is configured as follows.

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

According to a third aspect of the present invention, there is provided a piezoelectric substrate, a surface acoustic wave filter circuit formed on the piezoelectric substrate, the surface acoustic wave filter circuit having a plurality of comb-shaped electrode pairs, a space, and an input pad.
An output pad, a first ground pad, and a second ground pad separated and separated from the first ground pad, wherein the piezoelectric substrate is flip-chip bonded in the space. The package main body is housed, and the package main body is provided with a conductive cap so as to cover the space. The first ground pad and the second ground pad are interposed by the cap. Thus, it is possible to suppress the occurrence of interference between the potential of the first ground pad and the potential of the second ground pad, and the connection is made with some impedance. .

When the ground of the package body is separated and separated into the ground to which the ground for the input side comb-shaped electrode pair of the surface acoustic wave filter body is connected and the ground to which the ground for the output side comb-shaped electrode pair is connected. The interference between the ground potential of the input side comb-shaped electrode pair and the ground potential of the output side comb-shaped electrode pair is eliminated, and the amount of attenuation outside the pass band is improved by the amount that does not cause interference.

The cap includes the first ground pad and the second ground pad.
The configuration in which the cap is electrically connected to one of the ground pads improves the amount of attenuation outside the pass band as compared with the configuration in which the cap is not electrically connected to the ground pad. In the configuration in which the cap is electrically connected to the first ground pad via the first impedance and is electrically connected to the second ground pad via the second impedance, Compared to the configuration in which only one ground pad is electrically connected via the impedance, the amount of attenuation outside the pass band is improved.

Further, the cap is electrically connected to the first ground pad through the first impedance,
In addition, in the configuration in which the surface acoustic wave filter circuit is electrically connected to the second ground pad through the second impedance, the surface acoustic wave filter circuit is effectively shielded from electromagnetic waves, and the surface acoustic wave filter circuit is protected from external circuit devices. Effectively suppress the impact.

According to a fourth aspect of the present invention, in the third aspect , the surface acoustic wave filter circuit is formed on the piezoelectric substrate and has a first comb-shaped electrode connected to an input terminal.
A second comb-shaped electrode including a first comb-shaped electrode pair including a second comb-shaped electrode, a third comb-shaped electrode formed on the piezoelectric substrate and connected to the output terminal, and a fourth comb-shaped electrode. And the input terminal is connected to the input pad, the output terminal is connected to the output pad, and the second comb-shaped electrode is connected to the first ground pad. And the fourth comb-shaped electrode is connected to the second ground pad and is mounted on the package body.

According to a fifth aspect of the invention, in the third aspect , the impedance is formed in the package body. The invention of claim 6 is
In 3 , the first comb-shaped electrode pair and the second comb-shaped electrode pair are composed of a first surface acoustic wave filter element and a second surface acoustic wave filter element comb-shaped electrode pair cascade-connected thereto. And a second surface acoustic wave filter element, wherein the first surface acoustic wave filter element has the first comb-shaped electrode pair as an input comb-shaped electrode pair, and the second surface acoustic wave filter element comprises: The output comb-shaped electrode pair has the above-mentioned second comb-shaped electrode pair.

According to a seventh aspect of the present invention, in the third aspect , the package body has a bottom plate and a frame forming the space, and the bottom plate has an upper surface on which the first ground pad and the first ground pad are provided. It has two ground pads, the input pad and the output pad, and has a ground foot pattern, an input foot pattern, an output foot pattern and a special foot pattern on the lower surface thereof.

According to an eighth aspect of the present invention, in the seventh aspect , the ground foot pattern is connected to the first ground pad, and the special foot pattern is connected to the second ground pad. The input foot pattern is connected to the input pad, the output foot pattern is connected to the output pad, and the special foot pattern is connected to the ground and the pad formed on the printed circuit board. It is configured as follows.

[0033]

The invention of claim 9, Oite to claim 3, said surface acoustic wave filter circuit, and more become the first surface acoustic wave filter circuit and the second surface acoustic wave filter circuit, the first The surface acoustic wave filter circuit includes a first comb-shaped electrode pair and a second comb-shaped electrode pair formed on the piezoelectric substrate, the first comb-shaped electrode pair being connected to an input terminal. A first comb-shaped electrode and a second comb-shaped electrode, and the second comb-shaped electrode pair includes a third comb-shaped electrode connected to the first output terminal and a fourth comb-shaped electrode. The second
The surface acoustic wave filter circuit is composed of a third comb-shaped electrode pair and a fourth comb-shaped electrode pair formed on the piezoelectric substrate, and the third comb-shaped electrode pair is connected to the first comb-shaped electrode. A fifth comb-shaped electrode commonly connected to the input terminal and a sixth comb-shaped electrode, and the fourth comb-shaped electrode pair is a seventh comb-shaped electrode connected to the second output terminal. And the eighth
And a comb-shaped electrode.

[0035]

According to a tenth aspect of the present invention, there is provided a piezoelectric substrate, a surface acoustic wave filter circuit formed on the piezoelectric substrate, the surface acoustic wave filter circuit having a plurality of comb-shaped electrode pairs, a space, and an input pad and an output pad. And a first ground pad and a second ground pad separated from the first ground pad and housed in the space with the piezoelectric substrate being flip-chip bonded. And a cap provided on the package body so as to cover the space, the first ground pad and the second ground pad being connected to the potential of the first ground pad. The configuration is such that the occurrence of interference with the potential of the second ground pad can be suppressed and the connection is made with some impedance.

When the ground of the package body is separated and separated into the ground to which the ground for the input side comb-shaped electrode pair of the surface acoustic wave filter body is connected and the ground to which the ground for the output side comb-shaped electrode pair is connected. The interference between the ground potential of the input side comb-shaped electrode pair and the ground potential of the output side comb-shaped electrode pair is eliminated, and the amount of attenuation outside the pass band is improved by the amount that does not cause interference.

In the configuration in which the first ground pad and the second ground pad are electrically connected via the impedance, the first ground pad and the second ground pad are electrically connected via the impedance. The amount of attenuation outside the pass band is improved as compared with the configuration that does not. According to an eleventh aspect of the invention, in the tenth aspect , the impedance is formed in the package body.

According to a twelfth aspect of the present invention, in the tenth aspect , the surface acoustic wave filter circuit is formed on the piezoelectric substrate and has a first comb-shaped electrode connected to an input terminal and a second comb-shaped electrode. A first comb-shaped electrode pair including a comb-shaped electrode,
A second comb-shaped electrode formed on the piezoelectric substrate and connected to the output terminal, and a second comb-shaped electrode.
And the input terminal is connected to the input pad, the output terminal is connected to the output pad, and the second comb-shaped electrode is connected to the first ground pad. And the fourth comb-shaped electrode is connected to the second ground pad and is mounted on the package body.

According to a thirteenth aspect of the present invention, in the twelfth aspect , the first comb-shaped electrode pair and the second comb-shaped electrode pair are cascade-connected to the first surface acoustic wave filter element. A cascade connection surface acoustic wave filter circuit that is configured by the surface acoustic wave filter element of, wherein the first surface acoustic wave filter element has the first comb-shaped electrode pair as an input comb-shaped electrode pair, The output comb-shaped electrode pair has the above-mentioned second comb-shaped electrode pair.

According to a fourteenth aspect of the present invention, in the twelfth aspect , the package body has a bottom plate and a frame forming the space, and the bottom plate has an upper surface on which the first ground pad and the first ground pad are provided. It has two ground pads, the input pad and the output pad, and has a ground foot pattern, an input foot pattern, an output foot pattern and a special foot pattern on the lower surface thereof.

According to a fifteenth aspect of the present invention, in the fourteenth aspect , the ground foot pattern is connected to the first ground pad, and the special foot pattern is connected to the second ground pad. The input foot pattern is connected to the input pad, the output foot pattern is connected to the output pad, and the special foot pattern is connected to the ground and the pad formed on the printed circuit board. It is configured as follows.

[0043]

According to a sixteenth aspect of the present invention, in the tenth aspect , the surface acoustic wave filter circuit includes a first surface acoustic wave filter circuit and a second surface acoustic wave filter circuit. The wave filter circuit includes a first comb-shaped electrode pair and a second comb-shaped electrode pair formed on the piezoelectric substrate, and the first comb-shaped electrode pair is connected to an input terminal. The second comb-shaped electrode pair includes a comb-shaped electrode and a second comb-shaped electrode, and the second comb-shaped electrode pair includes a third comb-shaped electrode connected to the first output terminal and a fourth comb-shaped electrode. The surface acoustic wave filter circuit 2 includes a third comb-shaped electrode pair and a fourth comb-shaped electrode pair formed on the piezoelectric substrate, and the third comb-shaped electrode pair is the first comb-shaped electrode. A fifth comb-shaped electrode commonly connected to the input terminal, and a sixth comb-shaped electrode Rinari, the fourth interdigital electrode pair, and a seventh interdigital electrode being connected to the second output terminal, in which the more becomes constituting the comb-shaped electrode of the eighth.

[0045]

[0046]

[0047]

[0048]

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIGS. 8 to 12
Shows the SAW filter package device 100 according to the first embodiment of the present invention, and FIGS. 13 and 14 show the pass characteristics of the SAW filter package device 100 together with the pass characteristics of the conventional SAW filter 60. 12A is a plan view, FIG. 12B is a side view, and FIG. 12C is a bottom view.

The SAW filter package device 100 is
The SAW filter body 101 shown in FIG. 12 is mounted inside a box-shaped package body 102 and sealed by a cap 103. The SAW filter package device 100, except for a part thereof, has the structure shown in FIGS.
It has the same configuration as the conventional SAW filter 60 shown in FIG.

The box-shaped package body 102 includes the bottom plate 1
04 and a rectangular frame 105 fixed to this. As shown in FIG. 11 and FIG. 10, the bottom plate 104 has ground pads 110-1, 110-2, an input pad 111, and an output pad 112 on its upper surface, and its lower surface is at one diagonal position thereof. Ground foot pattern 113, 1
14. It has an input foot pattern 115 and an output foot pattern 116 at different diagonal positions. Also, via 117
The ground pad 110-1 and the ground foot pattern 113 are electrically connected by the via pad 118, the ground pad 110-2 and the ground foot pattern 114 are connected by the via pad 118, and the input pad 1 is connected by the via pad 119.
11 and the input foot pattern 115 are connected, and the via 1
Output pad 112 and output foot pattern 1 by 20
16 and 16 are connected.

As shown in FIG. 10, the via 125 inside the frame 105 connects the ground pad 110-1 and the cap 103. Ground pad 110-
2 and the cap 103 are not connected. FIG. 12 shows S
The AW filter main body 101 is shown. In FIG. 12, the terminals are denoted by the reference numerals shown in FIG. The SAW filter main body 101 includes a piezoelectric substrate 130.
On the lower surface of the SAW filter 40 (10-1, 10-2 of the dual mode type and cascade type shown in FIG. 3).
10-2) is made, and the input terminal 20A, the output terminal 22A, the ground terminal 21A for the input side comb-shaped electrode pair 11 of the first stage element 10-1, and the output of the second stage element 10-2. The ground terminal 47A for the side comb-shaped electrode pair 41 and the ground terminal 23A for the output side comb-shaped electrode pair 12, 13 of the first stage element 10-1.
(24A), the ground terminal 43A (44) for the input-side comb-shaped electrode pair 42, 43 of the second stage element 10-2.
A), input signal line pattern 13 shown with hatching
1 and the output signal line pattern 132, and dummy terminals 133 and 136 for balancing. Input terminal 20A, output terminal 46A, ground terminals 21A, 23
The A, 43A, 47A and the dummy terminals 133, 136 are distributed and arranged. Further, bumps (see FIG. 15A) for flip chip bonding are formed on each terminal.

As the piezoelectric substrate 130, a rotating Y plate of LiTaO3 is used, and its rotation angle is within the range of 40 ° Y to 44 ° Y. The comb-shaped electrode pair or the like is an electrode material containing Al as a main component and has a thickness of 5 to 10% of the wavelength of the surface wave. Alternatively, the piezoelectric substrate 130 uses a rotating Y plate of LiNbO3, and its rotation angle is within the range of 66 ° Y to 74 ° Y. The comb-shaped electrode pair or the like is an electrode material containing Al as a main component and has a thickness of 4 to 12% of the wavelength of the surface wave.

As shown in FIG. 10, the SAW filter body 101 is mounted on the bottom plate 104 of the package body 102 by the flip chip bonding method. As shown in FIG. 11, the input terminal 20A is in the portion of the input pad 111 indicated by reference numeral 111a, the output terminal 46A is in the portion of the output pad 112 indicated by reference numeral 112a, and the ground terminal 21A is in the ground pad 110-2. Reference numeral 110
-2a, the ground terminal 23A (24A) is a part of the ground pad 110-1, and the dummy terminal 133 is the ground pad 110-.
2, the ground terminal 47A is provided at a portion indicated by reference numeral 110-2b in FIG.
1b, the ground terminal 48A (49A) is a part of the ground pad 110-2 shown by a reference numeral 110-2c, and the dummy terminal 136 is a ground pad 110-1.
Of them are respectively connected to the portions indicated by reference numeral 110-1c.

The SAW filter package device 100 is
The ground foot patterns 113 and 114, the input foot pattern 115, and the output foot pattern 116 on the bottom surface are soldered to the corresponding pads on the printed board P and mounted on the printed board P. When the pass characteristic of the SAW filter package device 100 was measured with the SAW filter package device 100 mounted on the printed circuit board P, the pass characteristic shown by the line Ic in FIG. 13 was obtained in the vicinity of the target pass band near 950 MHz. When a wider frequency band up to 3 GHz was obtained, the pass characteristic shown by the line IIc in FIG. 14 was obtained.

In the vicinity of the target pass band near 950 MHz, the amount of attenuation outside the pass band is about 1 as compared with the conventional one.
It has increased by 0 dB and is improved. Wider 3 GHz
Even in the high frequency band up to, the amount of attenuation is improved by about 10 dB compared with the conventional one. As a result, harmonic noise of several GHz generated due to interference between a plurality of SAW filters having different pass bands incorporated in the high frequency part of the mobile phone is further attenuated and suppressed as compared with the conventional case.

SAW filter package device 100
The cap 103 so that the ground pad 110 is deformed.
-1 and the ground pad 110-2 are not connected, and the pass characteristics of this SAW filter package device are measured. As a result, the target pass band around 950 MHz is shown by line Ib in FIG. A pass characteristic was obtained. Comparing the pass characteristic shown by the line Ib, the pass characteristic shown by the line Ic, and the pass characteristic shown by the line Ia, the line Ib
It can be seen that although the pass characteristic indicated by (1) is improved over the pass characteristic indicated by the line Ia, it is not improved to the pass characteristic indicated by the line Ic. Assuming that the ground pad 110-1 and the ground pad 110-2 are separated from each other, the cap 103 is connected to the ground pad 110-1 via the via 125 inside the frame 105. It can be seen that the pass characteristic shown by is further improved to the pass characteristic shown by the line Ic.

Further, since the cap 103 is connected to the ground pad 110-1 via the via 125 inside the frame 105, the electromagnetic wave to the SAW filter body 101 mounted inside the box-shaped package body 102 is reduced. The shield is effectively provided, and the influence of the external circuit device on the SAW filter body 101 is effectively suppressed.

Next, the SAW filter package device 1 described above
00 will be described. Structure in which Ground is Separated and Separated As shown in FIG. 11, regarding the bottom plate 104, the ground pad 110-1 and the ground pad 110-2 are separated and separated by the separation portion 140. Therefore, looking at the package body 102,
The ground is separated into a first ground 141 including the ground pad 110-1, the via 117, and the ground foot pattern 113, and a second ground 142 including the ground pad 110-2, the via 118, and the ground foot pattern 114. Are separated.

With the SAW filter body 101 mounted on the bottom plate 104, the ground terminal 21A for the input-side comb-shaped electrode pair 11 of the first-stage single-type element 10-1 is connected to the ground pad 110-2. Yes,
The ground terminal 46A for the output-side comb-shaped electrode pair 46 of the second-stage single-type element 10-2 is connected to the ground pad 110-1.

Therefore, the SAW filter package device 100 before mounting is the first stage single type element 10
-1 and the ground for the input-side comb-shaped electrode pair 11 and the second
It has a structure in which the output side comb-shaped electrode pair 46 of the single-type element 10-2 of the stage is not common but separated by being separated. As shown in FIG. 1A, the ground 21 and the ground 47 are separated from each other.

In this way, the ground for the input side comb-shaped electrode pair 11 of the first stage single type element 10-1 and the ground for the output side comb-shaped electrode pair 46 of the second stage single type element 10-2 are used. Is separated and separated, the ground potential of the input side comb-shaped electrode pair 11 of the first stage single type element 10-1 and the output side of the second stage single type element 10-2. There is no interference with the ground potential of the comb-shaped electrode pair 46, so that the cause of limiting the increase in the amount of attenuation outside the pass band is eliminated, whereby the frequency band near the pass band is eliminated. Needless to say, even in the band of harmonic noise of several GHz, which is considerably higher than the pass band, the amount of attenuation outside the pass band is improved as compared with the conventional one. .

Structure in which the signal line pattern 131 (132) of the SAW filter main body 101 and the ground pads 110-1 (110-2) of the package main body 102 are separated from each other. As shown in an enlarged view of FIG. Each of the terminals of the main body 101 (for example, the ground terminal 21A and the dummy terminal 134 are shown) has two-stage bumps 150, 15
1 is formed, and a portion to which each pad of the package body 102 is connected (for example, a portion to which the pad is connected 11
0-1b and 110-2a), the Au plating layer 1
52 and 153 are formed. Au plating layer 152, 1
53 constitutes a heap portion. Two-stage bump 150, 151
Is formed by first forming bumps on the terminals and then forming bumps again on the formed bumps. Further, a printed layer of Au may be used instead of the Au plated layers 152 and 153.

The SAW filter body 101 is mounted with the two-stage bumps 150 and 151 fixed to the Au plating layers 152 and 153, respectively. Therefore, when the bump 155 of one step is connected to the pad 156 as in the conventional case shown in FIG. 15B, the signal line pattern 131 (132) is formed.
The distance between the ground pad 110-1 (110-2) and the ground pad 110-1 (110-2) is the dimension a1, whereas in the present embodiment, the distance shown in FIG.
As shown in FIG. 5B, the signal line pattern 131 (132) of the SAW filter body 101 and the package body 102.
The distance between the ground pads 110-1 (110-2) is about a2, which is more than doubled. As a result, the occurrence of interference between the signal of the SAW filter body 101 and the ground potential of the package body 102 is suppressed, and as a result, the amount of attenuation outside the pass band is improved.

The SAW filter main body 101 side may be a two-step bump and the package main body 102 side may be the same as the conventional structure. On the contrary, an Au plating layer may be formed on the package body 102 side and the SAW filter body 101 side may have a conventional configuration. Since the distance between the lower surface of the SAW filter main body 101 and the upper surface of the bottom plate of the package main body 102 is wide, S may be different due to variations in the height of the two-step bumps.
Regarding the posture when the AW filter main body 101 is mounted, the element of the SAW filter main body 101 does not come into contact with the upper surface of the bottom plate even if the degree of inclination is larger than in the conventional case. That is, when the SAW filter body 101 is mounted, the tilt angle allowed for the SAW filter body 101 is larger than that of the conventional one. Therefore, SAW filter 1
00 improves the yield at the time of assembly.

Seal Ring As shown in FIGS. 8 and 9A, the package body 10
A seal ring 160 is formed on the upper surface 105 a of the second rectangular frame 105. The seal ring 160 is a ridge having a semicircular cross section as shown in FIG.
It is formed along the circumference of 5 along the circumference. Seal ring 1
Reference numeral 60 denotes a space for accommodating solder, is made of tungsten, has a width w2 considerably narrower than the width w1 of the frame 105, and has a height h1 from the upper surface of the frame 105.
It is sticking out. An Au plating layer 161 is formed on the upper surface 105 a of the frame 105 and the surface of the seal ring 160. An AuSn solder film 162 is formed along the periphery on the lower surface of the cap 103.

When the cap 103 is set on the frame 105 and passed through the reflow furnace, the AuSn solder film 162 melts and the cap 103 is soldered to the frame 105 as shown in FIGS. 16 (B) and 16 (C). The SAW filter body 10
1 is sealed. 163 is solder. Here, the cap 103 is supported by the seal ring 160, a space 163 having a height h1 is formed between the cap 103 and the upper surface 105a of the frame 105, and the solder 163 is accommodated in the space 163. That is, the molten solder is accommodated in the height direction so as not to flow outside.

Conventionally, as shown in FIGS. 16D, 16E, and 16F, the seal ring is not formed, and the melted solder 164 is accommodated in the surface direction. Therefore, as can be seen by comparing FIGS. 16A to 16C with FIGS. 16D to 16F, the width w1 of the frame 105 can be narrower than the width w3 of the conventional frame 65. The width dimension w10 of the SAW filter 100 of this embodiment is the same as that of the conventional SAW filter 60.
The width dimension w11 of the SAW filter 100 is narrower than that of the SAW filter 100, and the SAW filter 100 of the present embodiment is smaller than the conventional one.

As described above, since the SAW filter 100 is small in size, it is advantageous in mounting the SAW filter 100 on a printed circuit board with high density. In the conventional SAW filter 60, the melted solder 164 is provided at each corner of the frame 65.
A notch 65b for accommodating excess solder is formed. The notch 65b has a large size b1 because the notch 65b is mainly for accommodating the solder.

On the other hand, the notch 105b of each corner portion of the frame 105 of the SAW filter 100 is not mainly intended to accommodate the solder, but the SAW filter 1
Since the main purpose is to confirm that 00 is normally mounted on the printed circuit board, the size b2 is small and small. Therefore, the strength of the package body 102 is not impaired by the notch 105b, and the SAW
The filter 100 also has improved package strength.

[Second Embodiment] FIGS. 17 to 19 show a SAW filter package device 1 according to a second embodiment of the present invention.
00A is shown. SAW filter package device 100A
1 in place of the SAW filter body 101 in FIG.
The SAW filter body 101A shown in FIG. 9 is mounted by flip-chip bonding. SAW
In the filter body 101A, the element 10 of the dual mode type and single type SAW filter shown in FIG. 1A is formed on the lower surface of the piezoelectric substrate 130, and
Input terminal 20A, output terminal 22A, input side comb-shaped electrode pair 1
1A ground terminal 21A, output side comb-shaped electrode pair 1
Ground terminals 23A (24A) for Nos. 2 and 13, an input signal line pattern 131 and an output signal line pattern 132 shown by hatching, and dummy terminals 133 to 136 for balancing are formed. Input terminal 20A,
The output terminal 22A, the ground terminals 21A and 23A, and the dummy terminals 133 to 136 are distributed and arranged. Further, bumps (see FIG. 15A) for flip chip bonding are formed on each terminal.

As shown in FIG. 18, the SAW filter body 101A is mounted on the bottom plate 104 of the package body 102 by the flip chip bonding method. The input terminal 20A is a portion of the input pad 111 indicated by reference numeral 111a, the output terminal 22A is a portion of the output pad 112 indicated by reference numeral 112a, and the ground terminal 21A is a portion of the ground pad 110-2 indicated by reference numeral 110-2a. The ground terminal 23A (24A) is connected to the ground pad 1
In the portion indicated by reference numeral 110-1a in 10-1, the dummy terminal 133 has the reference numeral 11 in the ground pad 110-2.
0-2b, the dummy terminal 134 in the portion of the ground pad 110-1 indicated by reference numeral 110-1b,
The dummy terminal 135 is connected to a portion of the ground pad 110-2 indicated by reference numeral 110-2c, and the dummy terminal 136 is connected to a portion of the ground pad 110-1 indicated by reference numeral 110-1c. That is, with the SAW filter body 101A mounted on the bottom plate 104, the ground terminal 21A for the input side comb-shaped electrode pair 11 is connected to the ground pad 110-2, and the output side comb-shaped electrode pair 1 is connected.
The ground terminals 23A (24A) for 2 and 13 are connected to the ground pad 110-1.

Therefore, in the SAW filter package device 100A before mounting, the ground for the input side comb-shaped electrode pair 11 and the ground for the output side comb-shaped electrode pairs 12 and 13 are not common but separated and separated. Have a structure. As shown in FIG. 1A, the grounds 23 and 24 and the ground 21 are separated and separated from each other.

Since the ground for the input-side comb-shaped electrode pair 11 and the ground for the output-side comb-shaped electrode pairs 12 and 13 are separated and separated as described above,
No interference occurs between the ground potential of the input-side comb-shaped electrode pair 11 and the ground potential of the output-side comb-shaped electrode pairs 12 and 13, so that the attenuation outside the pass band as in the first embodiment. The quantity is being improved.

[Third Embodiment] FIGS. 20 to 23 show a SAW filter package device 1 according to a third embodiment of the present invention.
00B is shown. SAW filter package device 100B
Is different from the SAW filter package device 100 shown in FIG. 8 only in the bottom plate of the box-shaped package body, and the degree of difference is small. The SAW filter body 101 shown in FIG. 12 is used as the SAW filter body.

As shown in FIG. 22, the bottom plate 104B has a first ground pad 410-1, a special pad 410-2, and a second ground pad 410- on its upper surface.
3, 410-4, input pad 411 and output pad 41
2 and. The first ground pad 410-1 and the special pad 410-2 are separated from each other.
The second ground pads 410-3 and 410-4 and the special pad 410-2 are separated from each other. Although the first ground pad 410-1 and the second ground pads 410-3 and 410-4 are geometrically separated from each other, they have a predetermined resistance value as described later. , More precisely, electrically connected by impedance. On the lower surface of the bottom plate 104B, the ground foot pattern 11 is provided at one diagonal position thereof.
3 and a special foot pattern 114B, and an input foot pattern 115 and an output foot pattern 116 at different diagonal positions.

The via 417 connects the first ground pad 410-1 and the ground foot pattern 113, the via 418 connects the special pad 410-2 and the special foot pattern 114B, and the via 419.
By the input pad 411 and the input foot pattern 115
And the output pad 412 and the output foot pattern 116 are connected by the via 420.

As shown in FIG. 23, the first ground pad 410-1 and the cap 103 are connected by the via 125 inside the frame 105. Similarly, frame 105
The second ground pads 410-3 and 410-4 are connected to the cap 103 by another via 125B inside. Therefore, the first ground pad 410-1
And the second ground pads 410-3 and 410-4 are
Via 125, cap 103 (seal ring 160),
It is electrically connected via the via 125B with a predetermined resistance value, more accurately, by impedance.
The predetermined resistance value (impedance) is equal to the potential of the first ground pad 410-1 and the second ground pad 41.
It is a certain value that can suppress the occurrence of interference with the potentials of 0-3 and 410-4.

As shown in FIG. 21, the SAW filter body 101 is mounted on the bottom plate 104B of the package body 102B by the flip chip bonding method. Figure 2
As shown in FIG. 1, the input terminal 20A (the primary side terminal for the input side comb-shaped electrode pair of the input stage side element) is connected to the input pad 411 and the output terminal 46A (the output side comb-shaped electrode pair of the output stage side element). Of the first ground pad 410-2 is connected to the output pad 412, and the ground terminal 21A (secondary terminal of the input side comb-shaped electrode pair of the element on the input stage side) is denoted by reference numeral 410 of the first ground pad 410-2. -2
The ground terminal 23A (24A) is the second
Of the first ground pad 410-1 to the dummy pad 133 of the first ground pad 410-1.
In the portion indicated by, the ground terminal 47A (the primary side terminal for the output side comb-shaped electrode pair of the element on the output stage side) is attached to the special pad 410-2 and the ground terminal 48A (49
A is a reference numeral 41 of the first ground pad 410-1.
The dummy terminals 136 are respectively connected to the second ground pads 410-4 at the portions indicated by 0-1a.

SAW filter package device 100B
Is a configuration having one input foot pattern 115, one output foot pattern 116, one ground foot pattern 113, and one special foot pattern 114B. The SAW filter package device 10
OB can be used in one mode selected from two modes. The first usage mode is a mode (a mode shown in FIG. 24C) in which the special foot pattern 114B is used as another (second) output terminal. The second usage mode is a mode in which the special foot pattern 114B is used as another ground terminal (a mode shown in FIG. 24E).
Is. Therefore, the SAW filter package device 100
B can be used in two ways and has a wide range of applications.

FIG. 24 shows a SAW filter package device 1.
The usage mode of 00B is shown. When the SAW filter package device 100B of FIG. 24A is used in the first usage mode, the pad 180 is connected to the ground, the pad 181 is connected to the first output terminal 46, and the pad 182 is connected to the input terminal 20.
The printed circuit board P1 shown in FIG. 7B is used in which the pad 183 is connected to the second output terminal 185. SAW
In the filter package device 100B, the ground foot pattern 113 is input to the pad 180, and the input foot pattern 1
15 to the pad 181, the output foot pattern 116 to the pad 182, and the special foot pattern 114B to the pad 1
It is soldered to 83. As a result, FIG.
A balanced SAW filter circuit 190 having one input terminal 20 and two output terminals, a first output terminal 46 and a second output terminal 185, can be realized as shown in FIG. Moreover, the balanced SAW filter circuit 190 is realized without using a balun circuit for converting unbalance to balance, which has been conventionally required. Therefore, the high frequency circuit part of the mobile phone can be constructed with a smaller number of parts than the conventional one.

This balanced SAW filter circuit 190
Has the advantage of being more resistant to noise than the one-input, one-output type, and has the advantage of improving the attenuation outside the pass band. This balanced SAW filter circuit 190 has nine
About the target pass band around 50MHz,
It has a pass characteristic shown by line Id in FIG. The line Id is the SAW filter package device 10 of the first embodiment of the present invention.
When compared with the line Ic, which has a passage characteristic of 0, it is 950M.
In the vicinity of the target pass band near Hz, the amount of attenuation outside the pass band increases by about 10 dB, and it can be seen that the improvement is further improved.

Looking at a wider frequency band up to 3 GHz, the pass characteristic shown by line IIB in FIG. 25 was obtained. Looking at this high frequency band up to 3 GHz,
The amount of attenuation is increased by about 10 dB compared with the conventional one, which is an improvement. When the SAW filter package device 100B of FIG. 24A is used in the second usage mode, the pad 180 is connected to the ground, the pad 181 is connected to the output terminal 46, and the pad 180 is connected to the output terminal 46.
The printed circuit board P2 shown in FIG. 9D is used in which the pad 182 is connected to the input terminal 20 and the pad 183 is connected to the ground. The SAW filter package device 100B includes the ground foot pattern 113 on the pad 180, the input foot pattern 115 on the pad 181, the output foot pattern 116 on the pad 182, and the special foot pattern 11
4B is soldered to the pad 183. As a result, as shown in FIG. 24E, the SAW filter circuit 19 has one input terminal 20 and one output terminal 46.
1 can be realized. SAW filter package device 100
SA when B is mounted on the printed circuit board P2
When the pass characteristic of the W filter package device 100B was measured, a pass characteristic substantially the same as the pass characteristic indicated by the line Id in FIG. 13 and a pass characteristic substantially the same as the pass characteristic indicated by the line IIB in FIG. 25 were obtained.

[Fourth Embodiment] FIG. 26 shows a SAW filter package device 100C according to a fourth embodiment of the present invention. S
The AW filter package device 100C includes a first ground pad 410-1 and a second ground pad 410-.
3, 410-4 are connected by a thin tungsten pattern 200 inside the bottom plate 104C.

The thin tungsten pattern 200 has a relatively high resistance value, more accurately, an impedance, and is connected to the first ground pad 410-1 and the second ground pads 410-3 and 410-4. There is impedance between them, and the ground potential of the first ground pad 410-1 and the second ground pads 410-3, 410
The interference with the ground potential of −4 is effectively prevented.

The cap 103 does not necessarily have to be conductive. When the pass characteristic of the SAW filter package device 100C was measured in a state where the SAW filter package device 100C was mounted on the printed circuit board P1, the pass characteristic substantially the same as the pass characteristic shown by the line Id in FIG. 13 and the line IIB in FIG. A pass characteristic substantially the same as the pass characteristic shown by was obtained.

[Fifth Embodiment] FIGS. 27A to 27D show a SAW filter package device 1 according to a fifth embodiment of the present invention.
00D is shown. SAW filter package device 100D
Is the SAW filter body 10 shown in FIGS.
1D is mounted by flip-chip bonding, and in terms of a circuit, as shown in FIG. 27D, a SAW filter circuit 210 of a first method and a SAW filter circuit 211 of a second method are provided. And a common input terminal 212 common to each SAW filter, an output terminal 213 of the SAW filter 210, and an output terminal 214 of the SAW filter 211.

As shown in FIG. 27A, the package body 209 has a common input pad 212a on the upper surface of the bottom plate.
And the first output pad 213a and the second output pad 2
14a, a first ground pad 215a, and a second ground pad 216a, and a ground foot pattern 217 and a common input foot pattern 2 on the bottom surface of the bottom plate.
12b, the first output foot pattern 213b, and the second
Output foot pattern 214b. The common input pad 212a and the common input foot pattern 212b are connected via a via in the bottom plate. The first output pad 213a and the first output foot pattern 213b are connected via a via in the bottom plate. Second output pad 2
14a and the second output foot pattern 214b are connected via a via in the bottom plate. The first ground pad 215a and the ground foot pattern 217 are connected via a via in the bottom plate. First ground pad 2
The space between 15a and the second ground pad 216a is shown in FIG.
Similarly, as shown in FIG. 5, electrical connection is made via a via and a cap (seal ring) with a predetermined resistance value, more accurately with impedance. The predetermined resistance value (impedance) is a certain value that can suppress the occurrence of interference between the potential of the first ground pad 215a and the potential of the second ground pad 216a.

The SAW filter body 101D is shown in FIG.
As shown in (A) and (B), the element 10-1 for the first method and the element 10 for the second method are provided on the piezoelectric substrate.
-2 are arranged side by side, and have a common input terminal 212c, an output terminal 213c of the element 10-1 for the first method, and an output terminal 214c of the element 10-2 for the second method. Furthermore, the element 10-1 for the first method
Terminal 218c for the input side comb-shaped electrode pair
A ground terminal 219c for the output side comb-shaped electrode pair of the element 10-1 for the first method, a ground terminal 220c for the input side comb-shaped electrode pair of the element 10-2 for the second method, and a second Element 10 for
Terminal 221 for the output side comb-shaped electrode pair
with c and.

In this SAW filter body 101D, the common input terminal 212c is connected to the common input pad 212a, the output terminal pad 213c is connected to the output pad 213a, and the output terminal pad 214c is connected to the output pad 213a.
, The ground terminal 218c and the two ground terminals 219c are connected to the first ground pad 215a, and the ground terminal 220c and the two ground terminals 221.
c is connected to the second ground pad 216a and mounted.

Therefore, the SAW filter package device 1
00D is the ground terminals 218c and 219c of the SAW filter 210 of the first method (first ground pad 215a and ground foot pattern 217).
And the ground terminals 220c and 221c (second ground pad 2) for the second type SAW filter 211.
16a) is designed so as not to cause interference, and is a dual type with improved passage characteristics.

[Sixth Embodiment] FIGS. 29A to 29D show a SAW filter package device 1 according to a sixth embodiment of the present invention.
00E is shown. SAW filter package device 100E
Is a configuration in which the SAW filter main body 101 shown in FIG. 12 is mounted with its pad facing upward, and the SAW filter main body 101 and the package main body are connected using wires.

The box-shaped package body 230 includes the bottom plate 23.
1 and a quadrangular frame 232 fixed thereto. As shown in FIGS. 29A and 29C, step portions 233 and 234 that are one step lower than the outside are provided on both inner sides of the frame 232, and the ground pad 235, the input pad 236, and the ground are provided on the step portion 233. Pad 237 is lined up,
A ground pad 238, an output pad 239, and a ground pad 240 are arranged on the step portion 234. As shown in FIG. 29B, on the upper surface of the bottom plate 231, the first ground pattern 241 and the second ground pattern 24 are formed.
2 and 2 are separated and formed, and an input pattern 243 and an output pattern 244 are further formed. On the lower surface of the bottom plate 231, as shown in FIG. 29D, the ground foot patterns 245 to 245 are provided at the respective corners.
248 and the input foot pattern 2 at the center of the opposite side
49 and an output foot pattern 250 are formed. The input pad 236 and the input pattern 243 are connected by the via in the frame 232, and the input pattern 243 and the input foot pattern 249 are connected by the via in the bottom plate 231. The output pad 239 and the output pattern 244 are connected by the via in the frame 232, and the output pattern 244 and the output foot pattern 250 are connected by the via in the bottom plate 231. FIG. 29 (C)
The ground pads 235 and 237 are connected to the frame 2 as shown in FIG.
The first ground pattern 2 is formed by the via 251 in 32.
41, and the first ground pattern 241 is connected to the ground foot patterns 246 and 248 by the via 252 in the bottom plate 231. Ground pad 2
38 and 240 are seconded by the via 253 in the frame 232.
Of the ground pattern 242, and the second ground pattern 242 is connected to the ground foot patterns 245 and 247 by the via 254 in the bottom plate 231.

The wire is the SAW filter body 101.
Of each terminal and the corresponding pads 235 to 240 are connected. In particular, the wire 260 is connected between the ground terminal 47A and the ground pad 235 for the output side comb-shaped electrode pair. The wire 261 is connected between the ground terminal 21A and the ground pad 240 for the input-side comb-shaped electrode pair.

Therefore, the SAW filter package device 1
00E is the ground terminal 2 for the input side comb-shaped electrode pair.
Ground terminal 47A for 1A and output side comb-shaped electrode pair
Has a configuration in which and are separated. Also,
A conductive cap 230c is provided on the upper surface of the box-shaped package body 230. The cap 230c has the same structure as that of FIG. 10, and the second ground pattern 2 is formed by the conductive wiring 232a formed inside the frame 232.
It is connected to 42. Therefore, similarly to the embodiment shown in FIG. 23, the cap 230c is electrically connected to the first ground pattern 241 and the second ground pattern 242 via the resistance R, more accurately, the impedance shown by the broken line. It is connected. Further, similarly to the embodiment shown in FIG. 26, a resistance R ′, more accurately, between the first ground pattern 241 and the second ground pattern 242,
It is electrically connected via the impedance shown by the broken line.

This SAW filter package device 100
When the pass characteristic of the SAW filter package device 100E was measured with E mounted on the printed circuit board, the result indicated by the line IE in FIG. 30 was obtained. A line Ia-1 is a passage characteristic when the ground patterns 241 and 242 are made common. As is clear from the comparison, the amount of attenuation outside the pass band is improved.

[Seventh Embodiment] FIGS. 31A to 31D show a ladder type SAW filter package device 100F according to a seventh embodiment of the present invention. The SAW filter package device 100F has a structure in which the SAW filter body 260 shown in FIGS. 32A and 32B is mounted with its pad facing upward, and the SAW filter body 260 and the package body are connected using wires. Is. The SAW filter body 260 is of a ladder type as shown in FIG.

The box-shaped package body 300 includes the bottom plate 30.
1 and a square frame 302 fixed to this. As shown in FIGS. 31 (A) and 31 (C), step portions 303 and 304 that are one step lower than the outside are provided on both inner sides of the frame 302, and the ground pad 305, the input pad 306, and the ground are provided on the step portion 303. Pad 307 is lined up,
A ground pad 308, an output pad 309, and a ground pad 300 are arranged on the step portion 304. As shown in FIG. 31B, the first ground pattern 311 and the second ground pattern 31 are formed on the upper surface of the bottom plate 301.
2 and 2 are separated and formed, and further, an input pattern 313 and an output pattern 314 are formed. On the lower surface of the bottom plate 301, as shown in FIG. 31 (D), ground foot patterns 315 to
318 and the input foot pattern 3 at the center of the opposite side
19 and an output foot pattern 320 are formed. The input pad 306 and the input pattern 313 are connected by the via in the frame 302, and the input pattern 313 and the input foot pattern 319 are connected by the via in the bottom plate 301. The output pad 309 and the output pattern 314 are connected by the via in the frame 302, and the output pattern 314 and the output foot pattern 320 are connected by the via in the bottom plate 301. FIG. 31 (C)
As shown in FIG.
The first ground pattern 3 is formed by the via 321 in 02.
11 and the first ground pattern 311 is connected to the ground foot patterns 315 and 316 by the via 322 in the bottom plate 301. Ground pad 3
08 and 310 are made second by the via 323 in the frame 302.
, And the second ground pattern 312 is connected to the ground foot patterns 317 and 318 by the via 324 in the bottom plate 301.

A conductive cap 302c is provided on the upper surface of the box-shaped package body 300. This cap 302c is connected to the second ground pattern 312 by a conductive wire 302a formed inside the frame 302, as in the configuration of FIG. Therefore, similarly to the embodiment shown in FIG. 23, the cap 302c is electrically connected to the first ground pattern 311 and the second ground pattern 312 via the resistance R, more accurately, the impedance shown by the broken line. It is connected. Furthermore, FIG.
Similarly to the embodiment shown in FIG. 6, the first ground pattern 31
The first and second ground patterns 312 are electrically connected to each other via a resistor R ′, more precisely, an impedance indicated by a broken line.

The SAW filter body 360 is shown in FIG.
As shown in (A) and (B), SAW resonators 362, 364, and 366 having reflectors on both sides are arranged in series on a piezoelectric substrate, and SAW resonators 361, 363 having the same configuration,
365 is a ladder type configuration in which parallel arms are arranged. SA
The W filter body 360 further includes an input terminal 306a,
Output terminal 309a and ground terminals 305a and 307
a and 308a.

Further, the wire is the SAW filter body 360.
Is connected between each terminal and the corresponding pads 305 to 310. The wire 330 is between the input terminal 306a and the input pad 306, the wire 331 is between the output terminal 309a and the output input pad 309, the wire 332 is between the ground terminal 305a and the ground pad 305, and the wire 333 is ground. Terminal 308a and ground pad 30
8 and the wire 334 is connected between the ground terminal 307a and the ground pad 307.

This ladder type SAW filter package device 100F has a ground foot pattern 316 (ground terminal 307a) close to the input foot pattern 319 (input terminal 306a) and a ground foot pattern 317 close to the output foot pattern 320 (output terminal 309a).
In this configuration, the (ground terminal 308a) is separated and separated.

This SAW filter package device 100
When the pass characteristics of the SAW filter package device 100F were measured with F mounted on the printed circuit board, the characteristics indicated by the line IF in FIG. 33A and the characteristics indicated by the line IIF in FIG. 33B were obtained. Compared with the pass characteristic (shown by line IIa-2) in the case where the ground terminals 307a and 308a are separated and made common without being separated, a few G is outside the pass band.
Improvements in the amount of attenuation in the harmonic band of Hz have been achieved.

The concept of separating and separating the ground of the present invention can be applied to SAW filters of other types, and the same effect can be expected. In particular,
The SAW filter package device 100 of FIG.
It is applicable to ladder type SAW filter package devices such as the SAW filter package device 360 having the equivalent circuit shown in FIG. 1 and the SAW filter package devices 100A to 100F according to the second to seventh embodiments of the present invention. The characteristics are improved. Similarly, the configuration of FIG. 23 or FIG. 26 is also applicable to the ladder type SAW filter package devices 360 of the second to seventh embodiments of the present invention SAW filter package devices 100A to 100F.
The frequency characteristic is improved as described above.

[0105]

As described above, the invention of claim 1 provides a surface acoustic wave filter device comprising a surface acoustic wave filter circuit comprising a plurality of comb-shaped electrode pairs formed on a piezoelectric substrate . , The second ground pads are separated and separated from each other, and the piezoelectric substrate is
Since the chip is up-chip bonded and the cap is electrically connected to one of the first ground pad and the second ground pad, the ground potential of the input-side comb-shaped electrode pair is There is no interference with the ground potential of the output-side comb-shaped electrode pair, and the amount of attenuation outside the pass band can be improved by the amount that does not cause interference. In addition, since the cap has a configuration in which it is electrically connected to one of the first ground pad and the second ground pad, compared to a configuration in which the cap is not electrically connected to the ground pad, The attenuation outside the band can be improved, and the electromagnetic wave shield for the surface acoustic wave filter circuit can be effectively performed to effectively suppress the influence of the surface acoustic wave filter circuit from the external circuit device. I can.

According to a third aspect of the present invention, there is provided a surface acoustic wave filter device comprising a surface acoustic wave filter circuit comprising a plurality of comb-shaped electrode pairs formed on a piezoelectric substrate.
The ground pads are separated and separated from each other, the piezoelectric substrate is flip-chip bonded, and the first ground pad and the second ground pad are interposed by a cap. ,
The input side comb-shaped electrode has a configuration in which it is possible to suppress the occurrence of interference between the potential of the first ground pad and the potential of the second ground pad, and the connection is made with some impedance. There is no interference between the ground potential of the pair and the ground potential of the output-side comb-shaped electrode pair, and the amount of attenuation outside the pass band can be improved by the amount that does not cause interference. The cap is electrically connected to only one ground pad because the cap is connected to the first ground pad and the second ground pad through the impedances, respectively. Compared with the first aspect of the invention, the amount of attenuation outside the pass band can be further improved, and the electromagnetic wave shield for the surface acoustic wave filter circuit can be effectively performed so that the surface acoustic wave filter circuit receives from the external circuit device. The effect can be effectively suppressed.

According to a tenth aspect of the present invention, in a surface acoustic wave filter device comprising a surface acoustic wave filter circuit composed of a plurality of comb-shaped electrode pairs formed on a piezoelectric substrate, a plurality of ground pads are separated from each other and separated. The first and second ground pads are separated and separated from each other, the piezoelectric substrate is flip-chip bonded, and the first ground pad and the A configuration in which the second ground pad and the potential of the first ground pad and the potential of the second ground pad can be suppressed from interfering with each other with a certain impedance. Therefore, it is possible to prevent interference between the ground potential of the input side comb-shaped electrode pair and the ground potential of the output side comb-shaped electrode pair. , Amount that does not cause interference, it is possible to improve the attenuation in the outside of the pass band. Further, since the first ground pad and the second ground pad are electrically connected via the impedance, the amount of attenuation outside the pass band is further improved as compared with the invention of claim 1. You can do it.

[Brief description of drawings]

FIG. 1 is a diagram showing an element of a dual mode type single type SAW filter together with its operation principle.

FIG. 2 is a diagram showing frequency characteristics obtained by calculation of the SAW filter of FIG.

FIG. 3 is a diagram showing elements of a dual-mode cascade SAW filter.

FIG. 4 is an exploded perspective view of a conventional SAW filter.

FIG. 5 is a diagram showing a conventional SAW filter.

6 is an enlarged cross-sectional view taken along the line VI-VI in FIG.

FIG. 7 is a diagram showing a configuration of a ground pad or the like in FIG.

FIG. 8 is an exploded perspective view of the SAW filter according to the first embodiment of the present invention.

9 is a diagram showing the SAW filter of FIG.

10 is an enlarged cross-sectional view taken along the line XX in FIG.

FIG. 11 is a diagram showing a configuration of a ground pad or the like in FIG. 9.

FIG. 12 is a bottom view of the SAW filter body.

13 is a diagram showing pass characteristics of the SAW filter of FIG. 8 and another SAW filter mounted on a printed circuit board.

FIG. 14 is a diagram showing a high-frequency band pass characteristic of a SAW filter mounted on a printed circuit board.

FIG. 15 is an enlarged view showing a mounting portion of the SAW filter body on the package body.

FIG. 16 is an enlarged view showing a mounting portion of the cap.

FIG. 17 is an exploded perspective view of a SAW filter according to a second embodiment of the present invention.

FIG. 18 is a diagram showing a configuration of a ground pad or the like in FIG.

FIG. 19 is a bottom view of the SAW filter body.

FIG. 20 is an exploded perspective view of a SAW filter according to a third embodiment of the present invention.

FIG. 21 is a diagram showing the SAW filter of FIG. 20.

22 is a diagram showing a configuration of a ground pad or the like in FIG. 21. FIG.

23 is a cross-sectional view of the SAW filter of FIG.

FIG. 24 is a diagram showing a usage state of mounting the SAW filter of FIG. 20.

FIG. 25 is the S of FIG. 20 mounted on the printed circuit board P1.
It is a figure which shows the high frequency band pass characteristic of an AW filter.

FIG. 26 is a diagram showing a SAW filter according to a fourth embodiment of the present invention.

FIG. 27 is a diagram showing a SAW filter according to a fifth embodiment of the present invention.

28 is a diagram showing the SAW filter body in FIG. 27. FIG.

FIG. 29 is a diagram showing a SAW filter according to a sixth embodiment of the present invention.

FIG. 30 is a diagram showing a pass characteristic of the SAW filter of FIG. 20.

FIG. 31 is a diagram showing a SAW filter according to a seventh embodiment of the present invention.

FIG. 32 is a diagram showing a SAW filter body in FIG. 31.

FIG. 33 is a diagram showing a pass characteristic of the SAW filter of FIG. 31.

[Explanation of symbols]

100, 100A-100F SAW filter package device 103 Cap 110-1, 110-2, 110-2A Ground pad 140 Separation part 150, 151 Two-step bump 152, 153 Au plating layer 160 Seal ring 200 Pattern 212a Common input pad 213a 1st output pad 214a 2nd output pad 215a, 410-1 1st ground pad 216a, 410-3, 410-4 2nd ground pad 410-2 Special pad

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-263509 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H03H 9/25 H03H 9/145 H03H 9 / 64

Claims (16)

(57) [Claims] 1. A piezoelectric substrate, a surface acoustic wave filter circuit formed on the piezoelectric substrate and comprising a plurality of comb-shaped electrode pairs, a space, and an input pad and an output pad separated from each other. A package body having a first ground pad and a second ground pad which are separated from each other, and wherein the piezoelectric substrate is accommodated in the space together with the surface acoustic wave filter circuit in a flip chip bonded state. , The package body is provided so as to cover the space, and the first ground pad and the second ground pad are provided.
Conductive cap that is electrically connected to one of the
The surface acoustic wave filter circuit is formed on the piezoelectric substrate and is connected to the input terminal.
A first comb-shaped electrode and a second comb-shaped electrode
Is formed on the piezoelectric substrate and the comb-shaped electrode pair of
A second comb-shaped electrode and a fourth comb-shaped electrode
It has a comb-shaped electrode pairs and said piezoelectric substrate, said input terminal connected to said input pad, said output terminal
Is connected to the output pad, and the second comb-shaped electrode is
Connected to the first ground pad and forming the fourth comb shape
The electrode is connected to the second ground pad, and
The first ground pad and the second ground pad are mounted on the package main body.
Is characterized in that it is connected via an impedance of a certain degree capable of suppressing interference between the potential of the first ground pad and the potential of the second ground pad. And a surface acoustic wave filter device. 2. The impedance of the package
The structure formed on the main body.
The surface acoustic wave filter device according to 1. 3. A piezoelectric substrate and a plurality of comb-shaped electrode pairs formed on the piezoelectric substrate.
A surface acoustic wave filter circuit having a space, an input pad, an output pad, and a first pad.
Separated from the ground pad and the first ground pad
A second ground pad that is separated by
The piezoelectric substrate is flip-chip bonded in the space.
The package body is housed in a closed state, and is provided in the package body so as to cover the space.
A conductive cap, the first ground pad and the second ground pad
And the first cap by means of the cap.
The potential of the ground pad and the voltage of the second ground pad
It is possible to suppress interference with
With the impedance that is
A surface acoustic wave filter device characterized by the above. 4. The surface acoustic wave filter circuit is formed on the piezoelectric substrate and is connected to an input terminal.
A first comb-shaped electrode and a second comb-shaped electrode
Is formed on the piezoelectric substrate and the comb-shaped electrode pair of
A second comb-shaped electrode and a fourth comb-shaped electrode
Has a comb-shaped electrode pairs and said piezoelectric substrate, said input terminal connected to the input pad
The output terminal is connected to the output pad,
The second comb-shaped electrode is connected to the first ground pad.
And the fourth comb-shaped electrode serves as the second ground pad.
With the configuration that is connected and mounted on the package body
The surface acoustic wave filter device according to claim 3, wherein 5. The impedance of the package is the same as that of the package.
Claim characterized by being formed in the main body
Item 3. The surface acoustic wave filter device according to item 3 . 6. The first comb-shaped electrode pair and the second comb.
The pair of shaped electrodes is the same as the first surface acoustic wave filter element.
Second surface acoustic wave filter cascade-connected to this
Surface acoustic wave composed of a pair of element comb electrodes
A filter circuit is constituted, and the first surface acoustic wave filter element is an input comb
Having the first pair of comb-shaped electrodes as a pole pair, and the second elastic
The surface acoustic wave filter element works as an output comb electrode pair.
It is characterized in that it has a structure having a second comb-shaped electrode pair.
The surface acoustic wave filter device according to claim 3 . 7. The package body forms the space.
Has a bottom plate and a frame, and the bottom plate has an upper surface on which the first ground pad and the upper surface are formed.
The second ground pad, the input pad, and the output pad
And a ground foot pattern on the lower surface thereof.
Special with input and output foot patterns
Characterized by having a foot pattern
The surface acoustic wave filter device according to claim 3 . 8. The ground foot pattern is the first
It is connected to the ground pad of the
Is connected to the second ground pad,
The input foot pattern is connected to the above input pad,
The output foot pattern is connected to the output pad.
Ri, the special foot pattern is connected to the ground pre
It is connected to the pad formed on the substrate.
The surface acoustic wave filter device according to claim 7, characterized in that . 9. The surface acoustic wave filter circuit according to claim 1, wherein
Surface acoustic wave filter circuit and second surface acoustic wave filter circuit
The first surface acoustic wave filter circuit is formed on the piezoelectric substrate.
The formed first comb-shaped electrode pair and the second comb-shaped electrode pair
And the first comb-shaped electrode pair is connected to the input terminal.
The first comb-shaped electrode and the second comb-shaped electrode
The second comb-shaped electrode pair is connected to the first output terminal.
The third surface-acoustic-wave filter circuit is composed of a third comb-shaped electrode and a fourth comb-shaped electrode .
The formed third comb-shaped electrode pair and the fourth comb-shaped electrode pair are
And the third comb-shaped electrode pair is the same as the first comb-shaped electrode.
Fifth comb-shaped electrode commonly connected to the input terminal
And a sixth comb-shaped electrode, and the fourth comb-shaped electrode pair
Is a seventh comb-shaped electrode connected to the second output terminal
And an eighth comb-shaped electrode,
The surface acoustic wave filter device according to claim 3 Symbol mounting to. 10. A piezoelectric substrate and a plurality of comb-shaped electrode pairs formed on the piezoelectric substrate.
A surface acoustic wave filter circuit having a space, an input pad, an output pad, and a first pad.
Separated from the ground pad and the first ground pad
A second ground pad that is separated by
The piezoelectric substrate is flip-chip bonded in the space.
The package body is housed in a closed state, and is provided in the package body so as to cover the space.
A first cap and a second ground pad
And the potential of the first ground pad and the second ground pad.
Suppresses interference with the potential of the land pad
It is possible to connect with a certain impedance
A surface acoustic wave filter device having the above structure. 11. The impedance of the package
Claim characterized by being formed in the main body
Item 10. The surface acoustic wave filter device according to item 10 . 12. The surface acoustic wave filter circuit is formed on the piezoelectric substrate and is connected to an input terminal.
A first comb-shaped electrode and a second comb-shaped electrode
Is formed on the piezoelectric substrate and the comb-shaped electrode pair of
A second comb-shaped electrode and a fourth comb-shaped electrode
Has a comb-shaped electrode pairs and said piezoelectric substrate, said input terminal connected to the input pad
The output terminal is connected to the output pad,
The second comb-shaped electrode is connected to the first ground pad.
And the fourth comb-shaped electrode serves as the second ground pad.
With the configuration that is connected and mounted on the package body
The surface acoustic wave filter device according to claim 10, wherein 13. The first comb-shaped electrode pair and the second comb-shaped electrode pair.
The comb-shaped electrode pair serves as a first surface acoustic wave filter element.
A second surface acoustic wave fill cascade connected to this
Cascade connection elasticity, which is composed of data elements
A surface acoustic wave filter circuit is constituted, and the first surface acoustic wave filter element is an input comb-shaped electric wave element.
An output comb electrode having the first comb electrode pair as a pole pair
A structure having the above-mentioned second comb-shaped electrode pair as a pair
The surface acoustic wave filter device according to claim 12 . 14. The package body defines the space.
Has a bottom plate and a frame, and the bottom plate has an upper surface on which the first ground pad and the upper surface are formed.
The second ground pad, the input pad, and the output pad
And a ground foot pattern on the lower surface thereof.
Special with input and output foot patterns
Characterized by having a foot pattern
The surface acoustic wave filter device according to claim 12 . 15. The ground foot pattern has the first pattern.
It is connected to the ground pad of No. 1 and
The turn is connected to the second ground pad above,
The input foot pattern is connected to the input pad above.
The output foot pattern is connected to the output pad.
There Te, the special foot pattern is connected to the ground pre
It is connected to the pad formed on the substrate.
The surface acoustic wave filter device according to claim 14, wherein 16. The surface acoustic wave filter circuit according to claim 1,
Surface acoustic wave filter circuit and second surface acoustic wave filter
And a first surface acoustic wave filter circuit on the piezoelectric substrate.
The formed first comb-shaped electrode pair and the second comb-shaped electrode pair
And the first comb-shaped electrode pair is connected to the input terminal.
The first comb-shaped electrode and the second comb-shaped electrode
The second comb-shaped electrode pair is connected to the first output terminal.
The third surface-acoustic-wave filter circuit is composed of a third comb-shaped electrode and a fourth comb-shaped electrode .
The formed third comb-shaped electrode pair and the fourth comb-shaped electrode pair are
And the third comb-shaped electrode pair is the same as the first comb-shaped electrode.
Fifth comb-shaped electrode commonly connected to the input terminal
And a sixth comb-shaped electrode, and the fourth comb-shaped electrode pair
Is a seventh comb-shaped electrode connected to the second output terminal
And an eighth comb-shaped electrode,
The surface acoustic wave filter device according to claim 1 0, wherein the.