JP2000183679A - Grating type surface acoustic wave filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance power resistance by enhancing heat resistance of a grating type surface acoustic wave(SAW) filter. SOLUTION: While an electrode 30a of the SAW resonator formed on a substrate is made of Al or an Al alloy, a connection pattern 34 for interconnecting SAW resonators and a bonding pad are made of the Al or Al alloy film 36 vapor-deposited on the substrate and an Au film 37 vapor- deposited on the film 36. Since Au has a thermal conductivity higher than that of the Al or Al alloy film 36, the heat generated through vibration of the electrode 30a of the SAW resonator is delivered to the Au film 37, and then dissipated so as to enhance the heat resistance of the SAW filter thereby improving the resistance to power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SA in which a one-terminal-pair surface acoustic wave (hereinafter referred to as "SAW") resonator having electrodes formed on a piezoelectric or ferroelectric substrate is connected in a multistage ladder shape.
It relates to a W filter.

[0002]

2. Description of the Related Art Conventionally, as a technique relating to a SAW filter using a SAW resonator, there is a technique described in the following document, for example. Reference 1: IEICE Transactions A, J76-A [2] (1993)
−2), Sato et al., “Low-Loss Bandpass Filter Using SAW Resonator” P.245-252 Reference 2; IEICE Transactions A, J76-A [2] (1993)
−2), Hikita et al., “Experiment on SAW Filters for Mobile Radio Communication Equipment”, P.233-244 Reference 3; Transactions of the Japan Society of Applied Physics, 36 [5B] (1997
-5), Noritoshi Kimura et al., “The Power Durabilit
y of 900MHz BandDouble-Mode-Type Surface Acoustic
Wave Filters and Improvement in Power Durability of
Al-Cu Thin FilmElectrodes by Cu Atom Segregation
Pp. 3101-3106 The documents 1 to 3 disclose the configuration of the SAW filter and the SAW filter.
It describes the life of the filter.

FIG. 2 is a circuit diagram showing a basic configuration of the conventional SAW filter shown in the above-mentioned documents 1-3.
3 is a characteristic diagram showing the frequency characteristics of FIG. One terminal pair S
A SAW filter in which AW resonators are connected in a ladder form has a SA
As shown in FIG. 2, the W resonator 10 is used for a series arm and a parallel arm, which are connected in a ladder form, and a high-frequency attenuation pole 13 of the filter is formed by the frequency characteristic 11 of the series arm. Is formed as a bandpass filter by forming a low-pass attenuation pole 14 of the filter by the frequency characteristic 12 of FIG.

FIG. 4 is a structural view showing a main part of the SAW resonator 10 shown in FIG. 2, which shows a perspective view and an enlarged view of a part A. The SAW resonator 10 is formed on the substrate 15
Electrode (hereinafter referred to as IDT) for transmitting and receiving
On both sides, a grating reflector 17 of a metal strip is arranged. From the theory of the constant K filter, a bandpass filter can be realized by matching the resonance frequency of the series arm with the antiresonance frequency of the parallel arm. Normally, the attenuation is insufficient with only one stage, and therefore, for example, a four-stage configuration is used.

FIG. 5 shows a ladder type SAW filter having a four-stage configuration.
FIG. 6 is a circuit diagram of the SAW filter of FIG.
FIG. 7 is a diagram showing a frequency characteristic of the SAW filter shown in FIG.
FIG. Ladder type SAW filter with four stages
, The SAW resonator 10 of the first-stage series arm _s1And two steps
SAW resonator 10 in series arm of eye_s2And the third arm
SAW resonator 10_s3And SAW resonator with fourth-stage series arm
10_s4And, it is the whole series arm. To this series arm
On the other hand, the SAW resonator 10 of the first-stage parallel arm_p1And two steps
SAW resonator 10 of the parallel arm of the eye_p2And the third stage of the parallel arm
SAW resonator 10_p3And SAW resonator of the fourth parallel arm
10_p4And are connected in a ladder form. FIG. 8 shows a conventional
It is sectional drawing which shows the manufacturing process of a SAW filter.

[0006] The SAW filter shown in FIG.
It is formed through the steps (a) to (e). First, FIG.
In the step (a), for example, the crystal orientation is 36 ° YX
LiTaO _ThreeA single crystal substrate 15 is prepared, and the substrate 15
Apply resist 18 by spin coating on the surface where turn is to be formed
I do. 8B, a resist 18 is applied.
The optical mask 19 is set for the substrate 15 thus
By exposing the resist 18 to the SAW film,
Transfer the pattern. In the step of FIG.
Unnecessary resist 18 is selectively removed by development. FIG.
In the step (d), the unnecessary resist 18 is removed.
The IDT 16 of the SAW resonator is formed on the entire surface of the
Al (aluminum) thin film 21 of electrode metal is deposited
You. In the step of FIG. 8E, A
l Remove unnecessary portions of the thin film 21 together with the resist 18.
You.

[0007]

However, the ladder type SAW filter has the following problems. Since both the SAW resonators in the series arm and the SAW resonators in the parallel arm use standing waves, the energy density is high and the power durability becomes stricter than that of a transversal filter. In addition, since the SAW is used, the energy of the wave is concentrated in a region within one wavelength from the surface of the substrate 15. That is, the energy density increases. This becomes particularly severe when there is input power on the order of watts, such as in recent years of antenna duplexers (duplexers) for mobile phones.

When a large power is input to the SAW device, a strong repetitive stress is applied to the IDT 16 for transmitting and receiving the SAW, so that the electrode metal Al generates migreleshun or generates heat. As a countermeasure against this, at present, Cu (copper) and Ti (titanium) are added to Al which is an electrode metal to improve the resistance to stress migration and the resistance to electromigration in the IDT 16, thereby improving the power resistance. However, in order to improve the power durability in this way, the added metal must be increased, and the added metal is unevenly distributed in Al,
There has been a problem that the additional metal remains during the etching and the resistance value increases.

[0009]

In order to solve the above problems, a first aspect of the present invention is to provide a piezoelectric or ferroelectric single crystal substrate in which Al or an Al alloy serving as an electrode is vapor-deposited, respectively. A plurality of formed one-port SAW resonators and a plurality of bonding pads for external connection are provided, and the plurality of one-terminal SAW resonators are connected in a ladder-like manner between the plurality of bonding pads by a connection pattern. The ladder type SAW filter is configured as follows.
That is, the connection pattern for connecting the one-terminal SAW resonator, the connection pattern for connecting the one-terminal SAW resonator and the bonding pad, and the bonding pad are formed of the piezoelectric or ferroelectric single crystal substrate. On the Al or Al alloy film deposited and formed on,
One or more heat dissipation films made of a metal having a higher thermal conductivity than the Al or Al alloy are stacked.

According to a second aspect of the present invention, a ladder type SAW filter has the following configuration. That is, the connection pattern for connecting the one-terminal SAW resonator, the connection pattern for connecting the one-terminal SAW resonator and the bonding pad, and the bonding pad are formed of the piezoelectric or ferroelectric single crystal substrate. The film is formed by depositing one or more layers thereon, and the Al or Al alloy film is stacked on a metal film having a higher thermal conductivity than the Al or Al alloy. According to the first and second aspects of the present invention, since the ladder-type SAW filter is configured as described above, the heat generated on the substrate by the vibration of the SAW resonator travels through the heat dissipation film.

According to a third aspect of the present invention, a ladder type SAW filter has the following configuration. That is, the connection pattern for connecting the one-terminal SAW resonator, the connection pattern for connecting the one-terminal SAW resonator and the bonding pad, and the bonding pad are formed of the piezoelectric or ferroelectric single crystal substrate. One or more layers are formed thereon by vapor deposition, and are formed of a metal film having a higher thermal conductivity than the Al or Al alloy. According to the third aspect, the ladder-type SAW filter is configured as described above.
The heat generated on the substrate by the vibration of the resonator is Al or A
Moves through a film of metal with higher thermal conductivity than alloy 1

According to a fourth aspect of the present invention, a ladder type SAW filter has the following configuration. That is, the connection pattern for connecting the one-terminal SAW resonator, the connection pattern for connecting the one-terminal SAW resonator and the bonding pad, and the bonding pad are formed of the piezoelectric or ferroelectric single crystal substrate. Deposited and formed on
The Al or A which is 50% or more thicker than the thickness of the electrode
It is composed of a 1 alloy film. According to the fourth aspect, the ladder-type SAW filter is configured as described above.
The heat generated on the substrate by the vibration of the resonator is Al or A
It travels along a thick film of the alloy.

According to a fifth aspect of the present invention, a ladder type SAW filter has the following configuration. That is, the connection pattern for connecting the one-terminal SAW resonator, the connection pattern for connecting the one-terminal SAW resonator and the bonding pad, and the bonding pad are formed of the piezoelectric or ferroelectric single crystal substrate. One or more layers of a dielectric having a higher thermal conductivity than the piezoelectric or ferroelectric single crystal substrate are laminated on the Al or Al alloy film formed by vapor deposition on the above. According to the fifth aspect, since the ladder-type SAW filter is configured as described above, the heat generated on the substrate by the vibration of the SAW resonator has a higher dielectric constant than the piezoelectric or ferroelectric single crystal substrate. Move along the body.

According to a sixth aspect of the present invention, a ladder type SAW filter has the following configuration. That is, the connection pattern for connecting the one-terminal SAW resonator, the connection pattern for connecting the one-terminal SAW resonator and the bonding pad, and the bonding pad are formed of the piezoelectric or ferroelectric single crystal substrate. A metal layer having a higher thermal conductivity than the Al or Al alloy and one layer of a dielectric material having a higher thermal conductivity than the piezoelectric or ferroelectric single crystal substrate. The above configuration is adopted. According to the sixth aspect of the present invention, since the ladder-type SAW filter is configured as described above, the heat generated on the substrate by the vibration of the SAW resonator is a metal film having a higher thermal conductivity than Al or an Al alloy and a piezoelectric film. Alternatively, it moves along a dielectric having a higher thermal conductivity than a ferroelectric single crystal substrate.

A seventh invention is directed to the fifth or sixth invention.
Thermal conductivity than the piezoelectric or ferroelectric single crystal substrate
High dielectric material, Al_TwoO_Three, AIN or Si_ThreeN_Four
It consists of. According to the seventh aspect, as described above, S
Since the AW filter is configured, Al_TwoO _Three, AIN again
Is Si_ThreeN_FourHas high thermal conductivity. Therefore, the heat generated
Escape through these.

In an eighth aspect, the Al alloy according to the first to sixth or seventh aspects is obtained by adding Cu, Ti or T to Al.
a is added. According to the eighth aspect, since the SAW filter is configured as described above, the migration resistance of the Al alloy is improved. The ninth invention is
In the first to third inventions or the sixth to eighth inventions, the metal having a higher thermal conductivity than Al or Al alloy is A
u, Ag or Cu. According to the ninth aspect, the SAW filter is configured as described above.
u, Ag or Cu has a high thermoelectric coefficient. Therefore, the heat generated by the heat escapes.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 9 is a schematic configuration diagram of a ladder-type SAW filter showing a first embodiment of the present invention, and FIG.
FIG. 4 is a perspective view showing a configuration of a W resonator 30 _s1 . The ladder-type SAW filter according to the first embodiment pays particular attention to heat resistance of electric power, and a pattern for connecting between each SAW resonator in the ladder-type SAW filter and a connection pattern for connecting between the SAW resonator and the bonding pad. Further, by evaporating, for example, Au (gold) having good thermal conductivity on the bonding pad, heat generated by the resonator that generates a large amount of heat is released to the resonator that generates less heat and an external circuit at the subsequent stage, thereby improving heat resistance. Thus, the withstand power is improved. In particular, there is a report that migration of electrodes is accelerated by heat generation, so it is important to disperse generated heat to improve heat resistance.

The ladder-type SAW filter of FIG. 9 is a four-stage SAW filter like the conventional SAW filter of FIG. 5, and has eight SAW resonators 30 _s1 , 30 _s2 , and 3.
0 _s3 , 30 _s4 , 30 _p1 , 30 _p2 , 30 _p3 , 30 _p4 , an input bonding pad 31, an output bonding pad 32, and a plurality of earth bonding pads 33. The SAW resonator 30 _s1 is a first-stage series arm resonator, the SAW resonator 30 _s2 is a second-stage series arm resonator, and the SAW resonator 30 _s3 is a third-stage series arm resonator. The SAW resonator 30 _s4 is a fourth-stage series arm resonator. The SAW resonator 30 _p1 is a first-stage parallel arm resonator, the SAW resonator 30 _p2 is a second-stage parallel arm resonator, and the SAW resonator 30 _p3 is a third-stage parallel arm resonator. The SAW resonator 30 _p4 is the fourth-stage parallel arm resonator.

The SAW resonator 30 _s1 has, as shown in FIG.
IDT3 formed of Al or Al alloy on substrate 35
0a and reflectors 30 formed on both sides of the IDT 30a
b, 30c. SAW resonator 30 _{s2 to} 3
0 _s4 and 30 _p1 to 30 _p4 also have the same IDT 30a and reflectors 30b and 30c. Each SAW resonator 30 _s1
To 30 _s4 , 30 _p1 to 30 _p4 , between the SAW resonator 30 _s1 and the input bonding pad 31, and between the SAW resonator 30
_s4 and the output bonding pad 32, and each SAW
Resonators 30 _p1 to 30 _p4 and earth bonding pad 33
Are connected by a connection pattern 34 to form a four-stage ladder-type circuit.

FIG. 1 is a perspective view of a pattern of a ladder-type SAW filter showing a first embodiment in FIGS. 9 and 10, and is an enlarged perspective view of a portion B in FIG. Bonding pads 31 to 33 and connection pattern 34
Is a film 3 of Al or Al alloy formed on the substrate 35
6 and a heat-dissipating film 37 of, for example, Au deposited thereon to improve the heat resistance.

FIGS. 11A to 11I are cross-sectional views showing the steps of manufacturing the SAW filter shown in FIG. The SAW filter of FIG. 9 is manufactured by sequentially performing the steps shown in FIGS. The outline of each step will be described below. First, in the step of FIG. 11A, for example, a LiTaO ₃ single crystal substrate 35 having a crystal orientation of 36 ° YX is prepared, and a resist 38 is applied to the surface of the substrate 35 on which a SAW resonator is to be formed by spin coating. . In the step of FIG. 11B, an optical mask 39 is set on the substrate 31 on which the resist 38 has been applied, and the resist 38 is exposed to light 40, whereby the SAW resonators 30 _s1 to 30 _s4 , 3
The patterns of 0 _p1 to 30 _p4 , the bonding pads 31 to 33 and the connection pattern 34 are transferred. In the step of FIG. 11C, the unnecessary resist 38 is selectively removed by development, and in the step of FIG.
An Al thin film 41 is deposited on the entire upper surface of the substrate 35 from which 8 has been removed. In the step of FIG. 11E, unnecessary resist 38 and AL thin film 41 are removed by lift-off using an organic solvent. Up to this point, the SAW resonator 30 _s1
30 _s4 , 30 _p1 -30 _p4 , bonding pad 31-
33 and a film 36 of the connection pattern 34 are formed on the substrate 35.

In the step of FIG. 11F, a resist 42 is applied again on the surface of the substrate 35 on which the SAW filters 30 _s1 to 30 _s4 , 30 _p1 to 30 _{p4 and the} like are formed. FIG.
In the step (g), the pattern of the film 37 is transferred by light exposure using an optical mask in the same manner as in the steps (b) and (c) of FIG.
2 is removed to expose the surface of the Al thin film 41. FIG.
In the step (h), an Au thin film 43 serving as the film 37 is deposited on the entire upper surface of the substrate 35 where the surface of the Al thin film 41 is exposed. In the step of FIG. 11I, the unnecessary thin film 43 is removed together with the resist 42 using an organic solvent. As described above, the film 37 is formed on the bonding pads 31 to 33 and the film 36.

Next, the operation of the SAW filter shown in FIG. 9 will be described. When a signal is applied to the input bonding pad 31 via a bonding wire (not shown), the serial arm SA
Power passes through the W resonators 30 _s1 to 30 _s4 , and a larger power is applied to the first stage. This is because the power is attenuated in the middle of the SAW resonator at a later stage. That is, it takes the largest power in series-arm SAW resonators 30 _s1, straight Retsuude increased heating value of the SAW resonator 30 _s1 is the best, most become stricter in power durability manner. Therefore, the withstand power of the series arm SAW resonator 30s1 will be described. Power input to the input bonding pad 31 enters the series arm SAW resonator 30 _s1 of the first stage, the power that passes through the series-arm SAW resonator 30 _s1 includes a series arm of the second-stage SAW resonator 30 _s2 First and second parallel arm SAW resonators 3
0 _p1 and 30 _p2 are input.

[0024] The power input to the series arm of the first stage SAW resonator 30 _s1, vibrates straight Retsuude SAW resonator 30 _s1, the area within one wavelength below the resonator 30 _s1 in the substrate 35 is A standing wave of the SAW is generated, thereby generating heat. The heat generated in the series arm SAW resonator 30 _s1 escapes along the heat dissipation routes R1 to R5 shown in FIG.

The heat radiating route R1 corresponds to the series arm SAW resonator 3
This is a route that is transmitted from the input electrode finger of 0 _s1 through the pattern 34 and transmitted to the external circuit through the bonding pad 31 and the bonding wire. The heat dissipation route R2 is a route transmitted from the output electrode finger of the series arm SAW resonator 30 _s1 to the pattern 34 and transmitted to the series arm SAW resonator 30 _s2 and the parallel arm SAW resonators 30 _p1 and 30 _p2 . The heat radiating route R3 is a route transmitted from the pattern 34 from the input electrode finger of the series arm SAW resonator 30 _s1 to the bonding pad 31 into the crystal of the substrate 35. Heat dissipation route R4
_Are output from the output-side electrode fingers of the series arm SAW resonator 30 _s1 to the series arm SAW resonator 30 _s2 and the parallel arm SAW resonator 30 _p1 ,
This is a route transmitted from the pattern 34 _reaching 30 _p2 to the crystal of the substrate 35. The heat radiating route R5 is a route in which heat generated in a region below the series arm SAW resonator 30 _s1 in the substrate 35 and having a depth of one wavelength or less is transmitted in the lateral direction and the depth direction of the substrate 35.

In the SAW filter according to the first embodiment, the bonding pads 31 to 33 and the connection patterns 34
On the film 36, a film 37 for heat radiation of Au is formed. Since the thermal conductivities of Al, Au and LiTaO ₃ are 237, 315 and 4.2 [W / (m · K)], respectively, the heat radiation effect in the heat radiation routes R1 to R4 is remarkably improved, and as a result heat resistance And the power durability is improved.

For example, in the frequency band of a 900 MHz mobile phone, the thickness ratio of the Al thin film 41 (= thickness H / frequency λ) is 11%, the thickness ratio of the Au thin film 43 is 5%, and the serial arm SA
The pattern 34 between the W resonator 30 _s1 and the bonding pad 31, the series arm SAW resonator 30 _s1 and the series arm SAW
A 6% temperature drop was observed even when evaluation was performed using a simple device in which the heat radiation film 37 was formed only on the pattern 34 between the resonator 30 _s2 and the parallel arm SAW resonator 30 _p1 . Therefore, heat generated in the vicinity of the surface of the substrate 35 is quickly radiated not through the inside of the crystal having poor thermal conductivity but through the film 37 on the surface.

As described above, in the first embodiment,
On the connection pattern 34 and the bonding pads 31 to 3
Since the heat radiation property is improved by forming the heat radiation film 37 on 3, a SAW filter having the following advantages can be obtained. (1) It is not necessary to add a large amount of metal to Al, and the metal to be added is not unevenly distributed in Al. (2) It is not necessary to add a large amount of metal to Al, and the added metal does not remain during etching. (3) It is not necessary to add a large amount of metal to Al, and the resistance does not increase. (4) Since Au is deposited on the film 36,
Can be prevented from peeling off. (5) Since Au is deposited on the film 36, the electrical resistance of the connection pattern 34 is reduced.

(6) Each of the SAW resonators 30 _s2 to 30 _s4 ,
Since the temperature rise at 30 _p1 to 30 _p4 is suppressed, the frequency change due to the temperature rise can be suppressed. (7) A conventional method of improving migration resistance by adding Cu, Ti, Ta or the like to Al of the electrode metal can be used in combination, and a synergistic effect can be expected. (8) In order to enhance the heat radiation effect, it is not necessary to expand the connection pattern and the bonding pad, so that the chip size does not need to be increased. (9) In order to enhance the heat radiation effect, it is not necessary to extend the connection pattern and the bonding pad, and the parasitic capacitance does not increase.

Second Embodiment FIG. 12 shows a ladder type SAW showing a second embodiment of the present invention.
FIG. 13 is a schematic configuration diagram of a filter, and FIG. 13 is a perspective view showing a configuration of the SAW resonator 50 _s1 in FIG. This ladder-type SAW filter is a four-stage SAW filter similarly to FIG. 9 showing the first embodiment, and has eight SAW filters.
Resonators 50 _s1 to 50 _s4 , 50 _p1 to 50 _p4 , an input bonding pad 51, an output bonding pad 52,
And a plurality of earth bonding pads 53.
The SAW resonator 50 _s1 is a first-stage series arm resonator,
The SAW resonator 50 _s2 is a resonator having a second-stage series arm,
The SAW resonator 50 _s3 is a third-stage series arm resonator,
The SAW resonator _50s4 is a fourth-stage series arm resonator.
The SAW resonator 50 _p1 is a resonator of the first-stage parallel arm,
The SAW resonator 50 _p2 is the resonator of the second-stage parallel arm,
The SAW resonator 50 _p3 is a third-stage parallel arm resonator,
The SAW resonator 50 _p4 is a fourth-stage parallel-arm resonator.

[0031] SAW resonator 50 _s1, as shown in FIG. 12, similar IDT50a and reflector in the first embodiment 5
0b and 50c. SAW resonator 50 _s2 to 50
_s4, 50 _p1 to 50 _p4, the same IDT50a and reflectors 50b, and has a 50c. Each SAW resonator 50 _s1 ~
50 _s4 , 50 _p1 to 50 _p4 , between the SAW resonator 50 _s1 and the input bonding pad 51, SAW resonator 50 _s4
And the output bonding pad 52, and between each of the SAW resonators 50 _p1 to 50 _p4 and the earth bonding pad 53 are connected by a connection pattern 54 to form a four-stage ladder circuit.

FIG. 14 is a sectional view of the second embodiment shown in FIGS.
FIG. 14 is a perspective view of a pattern of a ladder-type SAW filter showing the embodiment, and is an enlarged perspective view of a portion C in FIG. 13. In the first embodiment, the heat radiation film is formed on the connection pattern and the bonding pad. However, in the present embodiment, the connection pattern 54 and the bonding pad 51 are formed.
A film 56 for heat dissipation is formed between the lower side of the substrate 53 and the substrate 55. That is, on the film pattern 56 for heat radiation, Al
Alternatively, the structure is such that an Al alloy film 57 is laminated.

FIGS. 15A to 15I are cross-sectional views showing the steps of manufacturing the SAW filter shown in FIG. SAW of FIG.
The filter is manufactured by sequentially performing the steps shown in FIGS. The outline of each step will be described below. First, in the step of FIG. 15A, for example, a LiTaO ₃ single crystal substrate 55 having a crystal orientation of 36 ° YX
Is prepared, and a resist 58 is applied to the surface of the substrate 55 on which the SAW resonator is to be formed by spin coating. In the step of FIG. 15B, an optical mask 59 is set on the substrate 55 to which the resist 58 has been applied, and the substrate 58 is exposed to light 60 so that the heat radiation film 56 of the connection pattern 54 is formed on the resist 58.
Is transferred. In the step of FIG. 15C, unnecessary resist 58 is selectively removed by development, and FIG.
In step 5 (d), an Au thin film 61 is deposited on the entire upper surface of the substrate 55 from which the unnecessary resist 58 has been removed. In the step of FIG. 15E, unnecessary resist 58 and Au thin film 61 are removed by lift-off using an organic solvent. Through the steps so far, the film 56 is formed on the substrate 55.

In the step of FIG.
The resist 6 is again formed on the surface on which the heat radiation film 56 is formed.
2 is applied. In the step of FIG.
In the same manner as in the steps (b) and (c), light using an optical mask
Of the SAW resonator 50 _s1~ 50_s4, 50_p1~
50_p4, Bonding pads 51 to 53 and film 57
The turn is transferred, and the unnecessary resist 62 is
Is removed. The surface of the Au thin film 61 is exposed. FIG.
In the step (h), the surface of the Au thin film 61 was exposed.
The SAW resonator 50 is provided on the entire upper surface of the substrate 55._s1~ 50_s4,
50_p1~ 50_p4, And 57 are deposited.
You. In the step of FIG.
The necessary thin film 63 is removed together with the resist 62. Above
The SAW resonator 50_s1~ 50_s4, 50_p1~ 50_p4, Bo
Binding pads 51-53 and connection pattern 54,
It is formed.

Next, the operation of this SAW filter will be described with reference to FIG.
2 will be described with reference to the heat dissipation routes R1 to R5 shown in FIG.
You. Also in this ladder type SAW filter, bondin
The electric power inputted to the pad 51 is the first-stage serial arm SA.
W resonator 50_s1And the series arm SAW resonator 50 _s1But
Vibration generates heat. First-stage serial arm S
AW resonator 50_s1The electric power passed through is the second-stage series arm SA
W resonator 50_s2And first-stage parallel arm SAW resonator 50_p1When
Second-stage parallel arm SAW resonator 50_p2Entered as 1
The series serial arm SAW resonator 50_s1The heat generated in the first
Through the same heat radiation routes R1 to R5 as in the first embodiment.
I can.

Here, the ladder type SA of the second embodiment
In the W filter, since the heat radiation film 56 is formed in the connection pattern 54 and the bonding pads 51 to 53, the heat radiation routes R1 to R1 are formed in the same manner as in the first embodiment.
The heat radiation by R4 is overwhelmingly better than in the past. Furthermore, since the heat radiation film 56 is directly deposited on the substrate 55, especially at high frequency, when the connection pattern 54 is thin and the crystal of the substrate 55 is thick, or when the substrate crystal is fixed to a package having poor heat radiation. This is very effective when the substrate crystal is connected face down by bumps or the like, and heat radiation from the back surface of the substrate crystal cannot be expected.

As described above, in the second embodiment,
A heat-dissipating film 56 is formed below the connection pattern 54 and the bonding pads 51 to 53 to form each SAW resonator 50 _s1.
Ladder type S having the following advantages (11) to (17) because the heat radiation at ５０50 _s4 , 50 _p1 ５０50 _p4 has been improved.
An AW filter is obtained. (11) It is not necessary to add a large amount of metal to Al, and the metal to be added is not unevenly distributed in Al. (12) It is not necessary to add a large amount of metal to Al, and the added metal does not remain during etching. (13) It is not necessary to add a large amount of metal to Al, and the resistance does not increase.

(14) A film 56 for radiating Au is deposited under the film 57 of Al or AL alloy.
Film can be prevented from peeling off. (15) Since the Au thin film 61 is deposited under the connection pattern 54, the ohmic resistance of the connection pattern 54 decreases. (16) Each SAW resonator 50 _s1 to 50 _s4 , 50 _{p1 to} 5
Since the temperature rise at 0 _p4 is suppressed, a frequency change due to the temperature rise can be suppressed. (17) A conventional method of improving migration resistance by adding Cu, Ti, Ta or the like to Al as an electrode metal can be used in combination, and a synergistic effect can be expected.

Third Embodiment FIG. 16 shows a ladder type SAW according to a third embodiment of the present invention.
FIG. 17 is a schematic configuration diagram of a filter, and FIG. 17 is a perspective view illustrating a configuration of a SAW resonator 70 _{s1 in} FIG. 16. This ladder-type SAW filter is a four-stage SAW filter similarly to FIG. 9 showing the first embodiment, and has eight SAW filters.
Resonators 70 _s1 to 70 _s4 , 70 _p1 to 70 _p4 , an input bonding pad 71, an output bonding pad 72,
And a plurality of ground bonding pads 73.
The SAW resonator 70 _s1 is a first-stage series arm resonator,
The SAW resonator 70 _s2 is a resonator having a second-stage series arm,
The SAW resonator 70 _s3 is a third-stage series arm resonator,
The SAW resonator 70 _s4 is a resonator having a fourth series arm.
The SAW resonator 70 _p1 is the resonator of the first-stage parallel arm,
The SAW resonator 70 _p2 is a resonator of the second-stage parallel arm,
The SAW resonator 70 _p3 is a resonator having a third-stage parallel arm,
The SAW resonator 70 _p4 is the resonator of the fourth parallel arm.

As shown in FIG. 17, the SAW resonator 70 _s1 has the same IDT 70a and reflector 7 as in the first embodiment.
0b and 70c. SAW resonator 70 _s2 to 70
_s4, 70 _p1 to 70 _p4, the same IDT70a and reflectors 70b, and has a 70c. Each SAW resonator 70 _s1 ~
70 _s4 , 70 _p1 to 70 _p4 , between SAW resonator 70 _s1 and input bonding pad 71, SAW resonator 70 _s4
And the output bonding pad 72, and between each of the SAW resonators 70 _p1 to 70 _p4 and the earth bonding pad 73 are connected by a connection pattern 74 to form a four-stage ladder circuit.

FIG. 18 is a view showing a third example in FIGS. 16 and 17.
FIG. 18 is a perspective view of a pattern of a ladder-type SAW filter showing the embodiment, and is an enlarged view of a portion D in FIG. 17. In the first embodiment, a heat dissipation film is formed above the connection pattern and the bonding pad. In the present embodiment, however, these connection patterns 74 and the bonding pads 71 to 73 are replaced with the heat dissipation film 76. Just have formed. FIGS. 19A to 19I are cross-sectional views illustrating the steps of manufacturing the SAW filter of FIG.

The SAW filter shown in FIG.
It is manufactured by sequentially performing the steps shown in (i) to (i). The outline of each step will be described below. First, FIG.
In the step (a), for example, the crystal orientation is 36 ° YX
A LiTaO ₃ single crystal substrate 75 is prepared, and a resist 77 is spin-coated on the surface of the substrate 75 on which a SAW resonator is to be formed. In the step of FIG.
By setting an optical mask 78 on the substrate 75 coated with 7 and exposing the substrate to light 79, the pattern of the resonator is transferred to the resist 77. In the step of FIG. 19C, the unnecessary resist 77 is selectively removed by development, and in the step of FIG. 19D, an Al thin film 80 is deposited on the entire upper surface of the substrate 75 from which the unnecessary resist 78 has been removed. I do.
In the step of FIG. 19E, unnecessary resist 77 and unnecessary Al thin film 80 are removed by lift-off using an organic solvent. In the steps so far, the SAW resonators 70 _s1 to 70 _s1
s4 , _70p1 to _70p4 are formed on the substrate 75.

In the step of FIG.
SAW resonator 70_s1~ 70_s4, 70 _p1~ 70_p4Formed
The resist 81 is applied again on the surface that has been removed. FIG.
Step (g) is the same as the steps (b) and (c) in FIG.
In the same way, light exposure using an optical mask
Pattern of the bonding 74 and the bonding pads 71 to 73
Transfer and remove unnecessary resist 81 by subsequent development
The surface of the substrate 75 and the SAW resonator 70_s1~ 70_s4, 7
0_p1~ 70_p4Expose the end of Step of FIG. 19 (h)
In the above, the connection pattern 74 is
An Au thin film 82 is deposited. In the step of FIG.
Using an organic solvent to remove an unnecessary thin film 82 from the resist 81
Together with it. As described above, the connection pattern 74 and the button
Binding pads 71 to 73 are formed on substrate 75
You.

Next, the operation of this SAW filter will be described with reference to FIG.
6 will be described with reference to the heat dissipation routes R1 to R5 shown in FIG.
You. Also in this ladder type SAW filter, bondin
The power input to the touch pad 71 is
W resonator 70_s1And the series arm SAW resonator 70 _s1But
Vibration generates heat. First-stage serial arm S
AW resonator 70_s1The electric power passed through is the second-stage series arm SA
W resonator 70_s2And first-stage parallel arm SAW resonator 70_p1When
Second-stage parallel arm SAW resonator 70_p2Entered as 1
The series serial arm SAW resonator 70_s1The heat generated in the first
Through the same heat radiation routes R1 to R5 as in the first embodiment.
I can.

Here, the ladder type SA of the third embodiment
In the W filter, since the signal transmission pattern 74 and the bonding pads 71 to 73 are formed of the Au film 82, the heat radiation routes R1 to R4 are similar to the first embodiment.
Radiated heat is much better than before. Further, since the Au thin film 82 serving as a heat dissipation route is directly deposited on the substrate 75, the connection pattern 74 is particularly high frequency.
When the crystal of the substrate 75 is thin and the crystal of the substrate 75 is thick, or when the substrate crystal is fixed to a package with poor heat dissipation, the crystal substrate is connected face down by bumps, etc., and heat dissipation from the back surface of the crystal substrate cannot be expected. For example, it is very effective.

As described above, in the third embodiment,
The connection pattern 74 and the bonding pads 71 to 73 are formed of an Au film, and the SAW resonators 70 _s1 to 70 _s4 , 70 are formed.
_Since the heat radiation at _p1 to _p4 was improved, the following (21)
Thus, a ladder-type SAW filter having the advantage of (28) can be obtained. (21) It is not necessary to add a large amount of metal to Al, and the metal to be added is not unevenly distributed in Al. (22) It is not necessary to add a large amount of metal to Al, and the added metal does not remain during etching. (23) It is not necessary to add a large amount of metal to Al, and the resistance does not increase. (24) Since the connection pattern 74 is made of Au, the ohmic loss of the device can be reduced.

(25) Since the connection pattern 74 is formed by evaporating only Au, the film is prevented from peeling off due to poor adhesion to other metals, and a decrease in reliability due to diffusion in Al can be prevented. (26) Each SAW resonator 70 _s1 to 70 _s4 , 70 _{p1 to} 7
Since the temperature rise at 0 _p4 is suppressed, a frequency change due to the temperature rise can be suppressed. (27) A conventional method of improving migration resistance by adding Cu, Ti, Ta or the like to Al as an electrode metal can be used in combination, and a synergistic effect can be expected. (28) When the thin electrode finger and the thick connection pattern 74 are simultaneously etched or lifted off, there is a danger of etching or lifting off the excessively thin electrode finger.
In this embodiment, since the electrode fingers and the connection patterns 74 are formed in different steps, control is easy.

Fourth Embodiment FIG. 20 shows a ladder type SAW according to a fourth embodiment of the present invention.
FIG. 21 is a schematic configuration diagram of a filter, and FIG. 21 is a perspective view illustrating a configuration of a SAW resonator 90 _{s1 in} FIG. 20. This ladder-type SAW filter is a four-stage SAW filter similarly to FIG. 9 showing the first embodiment, and has eight SAW filters.
Resonators 90 _{s1 to} 90 _s4 , 90 _{p1 to} 90 _p4 , an input bonding pad 91, an output bonding pad 92,
And a plurality of ground bonding pads 93.

The SAW resonator 70 _s1 is a first-stage series arm resonator, the SAW resonator 70 _s2 is a second-stage series arm resonator, and the SAW resonator 90 _s3 is a third-stage series arm. The SAW resonator 90 _s4 is a fourth-stage series arm resonator. The SAW resonator 90 _p1 is a resonator of the first-stage parallel arm, the SAW resonator 90 _p2 is a resonator of the second-stage parallel arm, and the SAW resonator 90 _p3 is a resonance of the third-stage parallel arm. The SAW resonator 90 _p4 is a fourth-stage parallel arm resonator. As shown in FIG. 21, the SAW resonator 90 _s1 has the same IDT 90 a and reflector 9 as in the first embodiment.
0b and 90c. SAW resonator 90 _{s2 to} 90
_s4, 90 _p1 to 90 _p4, the same IDT90a and reflectors 90b, and has a 90c.

Each of the SAW resonators 90 _s1 -90 _s4 , 90 _p1-
90 _p4 , between the SAW resonator 90 _s1 and the input bonding pad 91, between the SAW resonator 90 _s4 and the output bonding pad 72, and each of the SAW resonators 90 _{p1 to} 90 p90.
_The connection between the _p4 and the earth bonding pad 93 by a connection pattern 94 constitutes a four-stage ladder circuit. FIG. 22 is a perspective view of a pattern of a ladder-type SAW filter showing the fourth embodiment in FIGS. 20 and 21, and shows an enlarged view of a portion E in FIG. In the first embodiment, a heat-dissipating film is formed above the connection patterns and the bonding pads. However, in the present embodiment, these connection patterns 94 and the bonding pads 91 to 91 are formed.
93 is formed only of the Al or Al alloy film 96 that is 50% or more thicker than the resonators 90 _{s1 to} 90 _s4 and 90 _{p1 to} 90 _p4 .

FIGS. 23 (a) to 23 (i) show the SAW of FIG.
It is sectional drawing which shows the manufacturing process of a filter. SA in FIG.
The W filter is manufactured by sequentially performing the steps shown in FIGS. The outline of each step will be described below. First, in the step of FIG. 23A, for example, a LiTaO ₃ single crystal substrate 9 having a crystal orientation of 36 ° YX
5 is prepared, and a resist 97 is applied to the surface of the substrate 95 on which a SAW resonator is to be formed by spin coating. In the step of FIG. 23B, an optical mask 98 is set on the substrate 95 on which the resist 97 has been applied, and the substrate is exposed to light 99, so that the resonator pattern is transferred to the resist 97. In the step of FIG. 23C, the unnecessary resist 97 is selectively removed by development, and in the step of FIG. 23D, an Al thin film 100 is deposited on the entire upper surface of the substrate 95 from which the unnecessary resist 98 has been removed. I do. In the step of FIG. 23E, unnecessary resist 97 and Al thin film 100 are removed by lift-off using an organic solvent. In the steps so far, the SAW resonators 90 _{s1 to} 90 _s4 and 90 _{p1 to} 90 _p4
Is formed on the substrate 95.

In the step of FIG.
SAW resonator 90_s1~ 90_s4, 90 _p1~ 90_p4Formed
The resist 101 is applied again on the surface that has been removed. FIG.
Step (g) is the same as the steps (b) and (c) in FIG.
In the same way, light exposure using an optical mask
Pattern of the bonding 94 and the bonding pads 91 to 93
Transfer, and remove unnecessary resist 101 by subsequent development
The surface of the substrate 95 and the SAW resonator 90_s1~ 90_s4,
90_p1~ 90_p4Expose the end of 23 (h)
In the process, the connection pattern 94 is formed on the entire upper surface of the substrate 95.
An Au thin film 102 is deposited. Step of FIG. 23 (i)
The unnecessary thin film 102 using an organic solvent
And is removed together with the object 101. As described above, connection pattern 9
4 and bonding pads 91 to 93
It is formed.

Next, the operation of this SAW filter will be described with reference to FIG.
0 will be described with reference to the heat dissipation routes R1 to R5 shown in FIG.
You. Also in this ladder type SAW filter, bondin
The power input to the touch pad 91 is the first-stage serial arm SA
W resonator 90_s1And the series arm SAW resonator 90 _s1But
Vibration generates heat. First-stage serial arm S
AW resonator 90_s1The electric power passed through is the second-stage series arm SA
W resonator 90_s2And first-stage parallel arm SAW resonator 90_p1When
Second-stage parallel arm SAW resonator 90_p2Entered as 1
First-stage series arm SAW resonator 90_s1The heat generated in the first
Through the same heat radiation routes R1 to R5 as in the first embodiment.
I can.

Here, the ladder type SA of the fourth embodiment is used.
In the W filter, since the connection pattern 94 and the bonding pads 91 to 93 are formed of a thick film of Al or an Al alloy, the heat radiated by the heat radiating routes R1 to R4 is smaller than that of the related art as in the first embodiment. And overwhelmingly improved. Furthermore, Al or an Al alloy serving as a heat radiation route is
Since the substrate crystal is vapor-deposited directly on the substrate 95, particularly at high frequencies, when the connection pattern 94 is thin and the crystal of the substrate 95 is thick, or when the substrate crystal is fixed to a package having poor heat dissipation, the substrate crystal may be bumped or the like. It is very effective when connected face down and heat radiation from the back surface of the substrate crystal cannot be expected.

As described above, in the fourth embodiment,
The connection pattern 94 and the bonding pads 91 to 93 are formed of thick Al or Al alloy, and each SAW resonator 90 is formed.
_{Since the} heat radiation at _{s1 to} 90 _s4 and 90 _{p1 to} 90 _p4 has been improved, the ladder type S has the following advantages (31) to (37).
An AW filter is obtained. (31) It is not necessary to add a large amount of metal to Al, and the metal to be added is not unevenly distributed in Al. (32) It is not necessary to add a large amount of metal to Al, and the added metal does not remain during etching. (33) There is no need to add a large amount of metal to Al, and the resistance does not increase. (34) Since the connection pattern 94 is made of Al,
No extra steps are required.

(35) Since the connection pattern 94 is formed by depositing only Al, it is possible to prevent the film from being peeled off due to poor adhesion to another metal and to prevent a decrease in reliability due to diffusion of the other metal into Al. (36) Each SAW resonator 90 _{s2 to} 90 _s4 , 90 _{p1 to} 9
Since the temperature rise at 0 _p4 is suppressed, a frequency change due to the temperature rise can be suppressed. (37) A conventional method of improving migration resistance by adding Cu, Ti, Ta or the like to Al as an electrode metal can be used in combination, and a synergistic effect can be expected.

[0057]Fifth embodiment FIG. 24 shows a ladder type SAW showing a fifth embodiment of the present invention.
FIG. 25 is a schematic configuration diagram of a filter, and FIG.
SAW resonator 110_s1It is a perspective view which shows a structure of. this
The ladder type SAW filter is different from FIG. 9 showing the first embodiment.
Similarly, the SAW filter has a four-stage configuration, and includes eight SAs.
W resonator 110_s1~ 110_s4, 110_p1~ 110_p4When,
The input bonding pad 111 and the output bonding pad
Pad 112 and a plurality of ground bonding pads 113
And SAW resonator 110_s1Is the first series
Arm resonator, SAW resonator 110 _s2Is the second stage
A row arm resonator, and a SAW resonator 110_s3Is the third stage
The SAW resonator 110 is a series arm resonator._s4Is the fourth stage
Is a series arm resonator. SAW resonator 110_p1Is one step
The SAW resonator 110 is a resonator of the parallel arm of the eye._p2Is 2
The SAW resonator 110 is a resonator of the parallel arm of the stage._p3But
The SAW resonator 110 is a resonator of the third parallel arm._p4
Is the resonator of the fourth parallel arm.

[0058] SAW resonator 110 _s1, as shown in FIG. 25, as in the first embodiment of IDT110a and reflectors 110b, and a 110c. SAW resonator 11
0 _{s2 to} 110 _s4 and 110 _{p1 to} 110 _p4 also have the same IDT.
110a and reflectors 110b and 110c.
Each SAW resonator 110 _{s1 to} 110 _s4 , 110 _{p1 to} 110
_p4 , between the SAW resonator 110 _s1 and the input bonding pad 111, between the SAW resonator 110 _s4 and the output bonding pad 112, and between each SAW resonator 110 _p1
.About.110 _p4 and the earth bonding pad 113 are connected by a connection pattern 114 to form a four-stage ladder circuit.

FIG. 26 is a view showing a fifth example of FIG. 24 and FIG.
26 is a perspective view of a pattern of a ladder-type SAW filter showing the embodiment, and is an enlarged perspective view of a part F in FIG. 25. FIG. In the first embodiment, the heat dissipation film is formed above the connection pattern and the bonding pad. However, in the present embodiment, the connection pattern 114 and the bonding pad 1 are formed.
A dielectric film 116 having a higher thermal conductivity than the substrate 115 is deposited on the upper side of 11 to 113 to improve heat resistance. FIGS. 27A to 27I are cross-sectional views illustrating the steps of manufacturing the SAW filter of FIG.

The SAW filter shown in FIG.
It is manufactured by sequentially performing the steps shown in (i) to (i). The outline of each step will be described below. First, FIG.
In the step (a), for example, the crystal orientation is 36 ° YX
LiTaO ₃ single crystal substrate 115 is prepared, and
The resist 117 is spin-coated on the SAW resonator forming surface No. 5 by spin coating. In the step of FIG. 27B, an optical mask 118 is set on the substrate 115 on which the resist 117 has been applied, and the resist 117 is exposed to light 119, so that the SAW resonators 110 _{s1 to} 110 _s4 , 11 are formed on the resist 117.
0 _{p1 to} 110 _p4 and bonding pads 111 to 113,
Then, the pattern of the connection pattern 114 is transferred. FIG.
In step 7 (c), resist 117 unnecessary for development is used.
Is selectively removed, and in the step of FIG. 27D, an Al thin film 120 is deposited on the entire upper surface of the substrate 115 from which the unnecessary resist 118 has been removed. In the step of FIG. 27E, unnecessary resist 117 and Al thin film 120 are removed by lift-off using an organic solvent. In the steps so far, the SAW resonators 110 _{s1 to} 110 _s4 and 110 _p1 to 1
10 _p4 , the _bases of the bonding pads 111 to 113 and the connection pattern 114 are formed on the substrate 115.

In the step of FIG.
SAW resonators 110 _{s1 to} 110 _s4 , 110 _{p1 to} 110
_The resist 121 is applied again on the surface on which _p4 is formed. In the step of FIG. 27 (g), FIGS.
In the same manner as in the step, by light exposure using an optical mask,
Connection pattern 114 and bonding pads 111-1
The pattern of No. 13 is transferred, and unnecessary resist 121 is removed by the subsequent development, and the underlying patterns of the connection pattern 114 and the bonding pads 111 to 113 are exposed.

In the step of FIG.
On the entire surface from above, a film 122 of, for example, Al ₂ O ₃ having a high conductivity and serving as the film 116 is deposited. Al ₂ O ₃
Has a thermal conductivity of 21 [W / (m · K)]. FIG.
In the step (i), an unnecessary film 12 is formed using an organic solvent.
2 is removed together with the resist 121. As described above, the connection pattern 114 having the film 116 on the upper side and the bonding pads 111 to 113 are formed on the substrate 115.

Next, the operation of this SAW filter will be described with reference to FIG.
4 will be described with reference to the heat dissipation routes R1 to R5 shown in FIG. Also in this ladder-type SAW filter, the power input to the bonding pad 91 is the same as that of the first-stage serial arm SA.
The W arm 110 _s1 enters the series arm SAW resonator 110
_{When s1} vibrates, heat is generated. The power passing through the first-stage series arm SAW resonator 110 _s1 is _equal to the second-stage series arm SAW resonator 110 _s2 , the first-stage parallel arm SAW resonator 110 _p1, and the second-stage parallel arm SAW resonator. 110 _p2 . The heat generated in the first-stage series arm SAW resonator 110 _s1 is dissipated in the same manner as in the first embodiment.
Run 5 and escape.

Here, the ladder type SA of the fifth embodiment
In the W filter, the film 11 having high thermal conductivity is formed on the connection pattern 114 and the bonding pads 111 to 113.
6, the heat radiation by the heat radiation routes R1 to R4 is overwhelmingly improved as compared with the related art, as in the first embodiment. Furthermore, especially at high frequencies, the connection pattern 11
When the substrate 4 is thin and the crystal of the substrate 115 is thick, or when the substrate crystal is fixed to a package having poor heat dissipation, the substrate crystal is connected face down by bumps or the like, and heat dissipation from the back surface of the substrate crystal cannot be expected. In some cases, it is very effective.

As described above, in the fifth embodiment,
Connection pattern 114 and bonding pads 111-1
13 is formed of an Al or Al alloy film and a dielectric film 116 having high thermal conductivity to form each of the SAW resonators 110 _s1 to 110 _s1.
Since the heat radiation at 10 _s4 , 110 _{p1 to} 110 _p4 has been improved, the ladder type S having the following advantages (41) to (47)
An AW filter is obtained. (41) It is not necessary to add a large amount of metal to Al, and the metal to be added is not unevenly distributed in Al. (42) It is not necessary to add a large amount of metal to Al, and the added metal does not remain during etching. (43) It is not necessary to add a large amount of metal to Al, and the resistance does not increase.

(44) Since the upper side of the connection pattern 114 becomes the dielectric film 116, the pattern can be protected. 0 (45) The dielectric film 116 is
It is also possible to vapor-deposit on portions other than the electrical characteristics other than the bonding pads 111 to 113, and by constructing a heat dissipation structure using the dielectric, heat dissipation to the outside can be further improved. (46) Each SAW resonator 110 _{s1 to} 110 _s4 , 110
Since the temperature rise in _p1 to 110 _p4 is suppressed, the frequency change due to the temperature rise can be suppressed. (47) It can be used in combination with a conventional method of improving migration resistance by adding Cu, Ti, Ta or the like to Al of the electrode metal, and a synergistic effect can be expected.

[0067]Sixth embodiment FIG. 28 is a ladder type SAW showing a sixth embodiment of the present invention.
FIG. 29 is a schematic configuration diagram of a filter, and FIG.
SAW resonator 130_s1It is a perspective view which shows a structure of. this
The ladder type SAW filter is different from FIG. 9 showing the first embodiment.
Similarly, the SAW filter has a four-stage configuration, and includes eight SAs.
W resonator 130_s1~ 130_s4, 130_p1~ 130_p4When,
The input bonding pad 131 and the output bonding pad
Pad 132 and a plurality of ground bonding pads 133
And SAW resonator 130_s1Is the first series
Arm resonator, SAW resonator 130 _s2Is the second stage
A row arm resonator, and a SAW resonator 130_s3Is the third stage
The SAW resonator 130 is a series arm resonator._s4Is the fourth stage
Is a series arm resonator. SAW resonator 130_p1Is one step
The SAW resonator 130 is a resonator of the parallel arm of the eye._p2Is 2
The SAW resonator 130 is a resonator of the parallel arm of the stage._p3But
The SAW resonator 130 is a third-stage parallel arm resonator._p4
Is the resonator of the fourth parallel arm.

[0068] SAW resonator 130 _s1, as shown in FIG. 29, as in the first embodiment of IDT130a and reflectors 130b, and a 130c. SAW resonator 13
0 _{s2 to} 130 _s4 and 130 _{p1 to} 130 _p4 are the same IDTs.
130a and reflectors 130b and 130c.
Each of the SAW resonators 130 _{s1 to} 130 _s4 , 130 _{p1 to} 130
_p4 , between the SAW resonator 130 _s1 and the input bonding pad 131, between the SAW resonator 130 _s4 and the output bonding pad 132, and between the SAW resonators 130 _p1
130 _p4 and the ground bonding pad 133 are connected by a connection pattern 134 to form a four-stage ladder circuit. FIG. 30 is a perspective view of a pattern of a ladder-type SAW filter showing the sixth embodiment in FIGS. 28 and 29, and shows an enlarged perspective view of a portion G in FIG. 29. In the first embodiment, a heat-dissipating film is formed above the connection pattern and the bonding pad. In the present embodiment, however, the connection pattern 134 and the bonding pads 131 to 133 are replaced with the Al or Al alloy film 136. It is formed on a substrate 135, a heat dissipation film 137 is stacked thereon, and a dielectric film 138 having high thermal conductivity is further stacked thereon to improve heat resistance.

FIGS. 31 (a) to 31 (m) show the SAW of FIG.
It is sectional drawing which shows the manufacturing process of a filter. SA in FIG. 28
The W filter is manufactured by sequentially performing the steps shown in FIGS. The outline of each step will be described below. First, in the step of FIG. 31A, for example, a LiTaO ₃ single crystal substrate 1 having a crystal orientation of 36 ° YX
35 is prepared, and a resist 139 is applied to the surface of the substrate 135 on which a SAW resonator is to be formed by spin coating. FIG.
In the step (b), an optical mask 140 is set on the substrate 135 coated with the resist 139, and light 141
The pattern of the SAW resonators 130 _{s1 to} 130 _s4 , 130 _{p1 to} 130 _p4 , the bonding pads 131 to 133, and the film 136 of the connection pattern 134 is transferred to the resist 139. In the step of FIG. 31C, the unnecessary resist 139 is selectively removed by development, and in the step of FIG.
9 is removed, an Al thin film 142 is formed on the entire upper surface of the substrate 135.
Is deposited. In the step of FIG. 31E, unnecessary resists 139 and A are lifted off using an organic solvent.
The thin film 142 is removed. In the steps so far, the SAW resonators 130 _{s1 to} 130 _s4 and 130 _{p1 to} 130 _p4 , the bonding pads 131 to 133, and the connection pattern 134
Is formed on the substrate 135.

In the step of FIG.
SAW resonators 130 _{s1 to} 130 _s4 and 130 _{p1 to} 130
_A resist 143 is applied again on the surface on which _{p4 and the} like are formed. In the step of FIG. 31 (g), FIGS.
In the same manner as in the step, by light exposure using an optical mask,
Connection pattern 134 and bonding pads 131-1
The pattern of the film 136 is transferred, and the unnecessary resist 143 is removed by the subsequent development.
4 and the pattern of the film 136 of the bonding pads 131 to 133 are exposed. In the step of FIG.
An Au thin film 144 to be a film 137 is deposited on the entire surface of the substrate 135 from above. In the step of FIG. 31I, the unnecessary film 144 is removed together with the resist 143 using an organic solvent.

In the step of FIG. 31 (j), the substrate 135
A resist 145 is again applied to the entire surface from above. In the step of FIG. 31K, similarly to the steps of FIGS. 31B and 31C, the connection pattern 134 and the pattern of the film 138 of the bonding pads 131 to 133 are transferred by light exposure using an optical mask. Then, in the subsequent development, the unnecessary resist 145 is removed, and the connection pattern 134 and the pattern of the film 137 of the bonding pads 131 to 133 are exposed. In the step of FIG.
On the entire surface from above, a film 146 of dielectric Al ₂ O ₃ having a high conductivity to be a film 138 is deposited. In the step of FIG. 31M, the unnecessary film 146 is removed together with the resist 145 using an organic solvent. As described above, the three-layer connection pattern 134 and the bonding pads 131 to 133 are
It is formed on a substrate 135.

Next, the operation of this SAW filter will be described with reference to FIG.
1 will be described with reference to the heat dissipation routes R1 to R5 shown in FIG. Also in this ladder type SAW filter, the power input to the bonding pad 131 is the same as that of the first-stage serial arm S.
The AW resonator 130 _s1 enters the series arm SAW resonator 13
When 0 _s1 vibrates, heat is generated. The power passing through the first-stage series arm SAW resonator 130 _s1 is _equal to the second-stage series arm SAW resonator 130 _s2 , the first-stage parallel arm SAW resonator 130 _p1, and the second-stage parallel arm SAW resonator. 130 _p2 . The heat generated in the first-stage series arm SAW resonator 130 _s1 is dissipated in the same manner as in the first embodiment.
Escape along R5.

Here, the ladder type SA of the sixth embodiment
In the W filter, the connection pattern 134 and the bonding pads 131 to 133 are formed by using an Al or Al alloy film 13.
6, the heat dissipation film 137 of Au, and the dielectric film 138 having a high thermal conductivity, as in the first embodiment, the heat dissipation by the heat dissipation routes R1 to R4 is smaller than that of the related art. It will be overwhelmingly better. Further, particularly at high frequencies, when the connection pattern 134 is thin and the crystal of the substrate 135 is thick, or when the substrate crystal is fixed to a package having poor heat dissipation, the substrate crystal is connected face down by bumps or the like,
When heat radiation from the back of the substrate crystal cannot be expected,
Very effective.

As described above, in the sixth embodiment,
Connection pattern 134 and bonding pads 131-1
33 is composed of a film 136 of Al or Al alloy, a film 137 for radiating Au, and a film 138 of a dielectric material having high thermal conductivity to improve heat radiation. 6
A ladder type SAW filter having the advantage of 0) is obtained. (51) It is not necessary to add a large amount of metal to Al, and the metal to be added is not unevenly distributed in Al. (52) It is not necessary to add a large amount of metal to Al, and the added metal does not remain during etching. (53) It is not necessary to add a large amount of metal to Al, and the resistance does not increase. (54) Since the Au film 137 is deposited on the Al film 136, peeling of the film 136 can be prevented. (55) Since the Au film 137 is deposited on the Al film 136, the cross-sectional area of the connection pattern 134 increases, and the resistance can be reduced.

(56) Each SAW resonator 130 _{s1 to} 13
Since the temperature rise at 0 _s4 , 130 _p1 to 10 _p4 is suppressed, the frequency change due to the temperature rise can be suppressed. (57) A conventional method of improving migration resistance by adding Cu, Ti, Ta, or the like to Al of the electrode metal can be used in combination, and a synergistic effect due to this can be expected. (58) On the connection pattern 134 Film 13 with dielectric side
8, the pattern can be protected. It is not necessary to add a special process made of Al. (59) Dielectric film 1 on top of connection pattern 134
Since it is 38, peeling of the Au film 137 can be prevented. (60) The dielectric film 138 can be deposited on portions other than the connection pattern 134 and the bonding pads 131 to 133 that do not affect the electrical characteristics. The heat radiation to the can be improved.

Note that the present invention is not limited to the above embodiment, and various modifications are possible. For example, there are the following modifications. (I) In the first to third embodiments and the fifth embodiment, Au is used as a metal having higher thermal conductivity than Al or AL alloy. However, Ag and Cu also have high thermal conductivity.
426 [W / (mK)] and 398 [W / (m
· K)], so that the same effect can be obtained by using these. (Ii) In the first, second and fifth embodiments, the metal films 37 and 56 having higher thermal conductivity than Al or the AL alloy are formed in one layer. You may. (Iii) In the fifth and sixth embodiments, the dielectric having a higher thermal conductivity than the substrate is Al ₂ O _3.
3 N ₄ is also available. The thermal conductivity of AIN or Si ₃ N ₄ is 200 [W / (m · K)], 5/5 [W / (m · K
K)]. Ag and Cu also had high thermal conductivity, and were 426 [W / (m · K)] and 398 [W /
(M · K)], the same effect can be obtained by using these.

(Iv) In the fifth and sixth embodiments, the dielectric films 116 and 138 having higher thermal conductivity than the substrate
Although a layer is used, a multilayer may be used. (V) On the film 76 of the third embodiment or on the film 96 of the fourth embodiment, a dielectric having a higher thermal conductivity than the substrate may be laminated with Al ₂ O ₃ . (Vi) In the manufacturing steps described in the first to sixth embodiments, lift-off is applied to Al or Al ₂ O ₃ , but etching may be performed.

[0078]

As described above in detail, according to the first and second aspects of the present invention, the connection pattern and the bonding pad are made of an Al or Al alloy film and a metal having a higher thermal conductivity. Since it is composed of the formed heat dissipation film, SA
The heat generated by the vibration of the W resonator travels through the heat dissipation film and escapes,
Improves heat resistance. Therefore, the power durability is improved. According to the third aspect, since the connection pattern and the bonding pad are formed of a metal film pattern having a higher thermal conductivity than Al or an Al alloy, heat generated by the vibration of the SAW resonator is transmitted through the film. Escape to improve heat resistance. Therefore, the power durability is improved. According to the fourth aspect, since the connection pattern and the bonding pad are made of an Al or Al alloy film that is at least 50% thicker than the thickness of the electrode of the SAW resonator, heat generated by the vibration of the SAW resonator is generated. It escapes through the film and improves heat resistance. Therefore, the power durability is improved.

According to the fifth aspect of the present invention, the connection pattern and the bonding pad are formed by depositing an Al or Al alloy film deposited on a piezoelectric or ferroelectric single crystal substrate and forming the piezoelectric or ferroelectric single crystal. Since one or more dielectrics having higher thermal conductivity than the crystal substrate are stacked, the heat generated by the vibration of the SAW resonator is transmitted through the dielectric and escapes to improve heat resistance. Therefore, the power durability is improved. According to the sixth aspect, the connection pattern and the bonding pad are formed on a metal film having a higher thermal conductivity than Al or an Al alloy by using a dielectric film having a higher thermal conductivity than the piezoelectric or ferroelectric single crystal substrate. , The heat generated by the vibration of the SAW resonator is transmitted through the metal film and the dielectric to escape, thereby improving heat resistance. Therefore, the power durability is improved.

According to the seventh invention, the dielectric according to the fifth or sixth invention is made of Al ₂ O ₃ , AIN or Si ₃
Since it is composed of N ₄ , the heat radiation effect can be ensured even if the piezoelectric or ferroelectric single crystal substrate is used for a normal SAW resonator or the like. According to the eighth invention, since the Al alloy in the first to sixth or seventh invention is obtained by adding Cu, Ti or Ta to Al, migration resistance can be further improved. According to the ninth aspect, the metal having a higher thermal conductivity than Al or the Al alloy in the first to third aspects or the sixth to eighth aspects is made of Au, Ag, or Cu. can get.

[Brief description of the drawings]

FIG. 1 is a perspective view of a pattern of a ladder type SAW filter according to a first embodiment.

FIG. 2 is a circuit diagram showing a basic configuration of a conventional SAW filter.

FIG. 3 is a characteristic diagram showing a frequency characteristic of FIG. 2;

FIG. 4 is a configuration diagram illustrating a main part of the SAW resonator 10 of FIG. 2;

FIG. 5 is a circuit diagram of a ladder-type SAW filter having a four-stage configuration.

FIG. 6 is a configuration diagram of the SAW filter of FIG. 5;

FIG. 7 is a characteristic diagram showing frequency characteristics of the SAW filter of FIG. 5;

FIG. 8 is a cross-sectional view illustrating a manufacturing process of a conventional SAW filter.

FIG. 9 is a schematic configuration diagram of a ladder-type SAW filter according to the first embodiment of the present invention.

FIG. 10 is a perspective view showing a configuration of a SAW resonator 30 _s1 in FIG. 9;

FIG. 11 is a sectional view showing a manufacturing process of the SAW filter of FIG. 1;

FIG. 12 shows a ladder-type SAW showing a second embodiment of the present invention.
It is a schematic block diagram of a filter.

13 is a perspective view showing a configuration of a SAW resonator 50 _s1 in FIG.

FIG. 14 is a perspective view of a pattern of a ladder type SAW filter showing a second embodiment.

FIG. 15 is a sectional view illustrating a manufacturing process of the SAW filter of FIG. 1;

FIG. 16 shows a ladder type SAW showing a third embodiment of the present invention.
It is a schematic block diagram of a filter.

17 is a perspective view illustrating a configuration of a SAW resonator 70 _s1 in FIG.

FIG. 18 is a perspective view of a pattern of a ladder-type SAW filter showing a third embodiment.

FIG. 19 is a sectional view showing a manufacturing process of the SAW filter of FIG. 16;

FIG. 20 shows a ladder-type SAW showing a fourth embodiment of the present invention.
It is a schematic block diagram of a filter.

21 is a perspective view showing a configuration of a SAW resonator 90 _s1 in FIG.

FIG. 22 is a perspective view of a pattern of a ladder-type SAW filter showing a fourth embodiment.

FIG. 23 is a sectional view showing a manufacturing process of the SAW filter of FIG. 20;

FIG. 24 shows a ladder-type SAW showing a fifth embodiment of the present invention.
It is a schematic block diagram of a filter.

25 is a perspective view showing a configuration of a SAW resonator 110 _s1 in FIG. 24.

FIG. 26 is a perspective view of a pattern of a ladder-type SAW filter showing a fifth embodiment.

FIG. 27 is a sectional view showing a manufacturing process of the SAW filter of FIG. 24;

FIG. 28 shows a ladder-type SAW showing a sixth embodiment of the present invention.
It is a schematic block diagram of a filter.

FIG. 29 is a perspective view showing a configuration of a SAW resonator 130 _s1 in FIG. 28.

FIG. 30 is a perspective view of a pattern of a ladder type SAW filter showing a sixth embodiment.

FIG. 31 is a sectional view showing a manufacturing process of the SAW filter of FIG. 28;

[Explanation of symbols]

10 _s1 to 10 _s4 , 10 _p1 to 10 _p4 , 30 _s1 to 30 _s4 , 3
0 _p1 to 30 _p4 , 50 _s1 to 50 _s4 , 50 _p1 to 50 _p4 , 70
_s1 to 70 _s4 , 70 _p1 to 70 _p4 , 90 _{s1 to} 90 _s4 , 90 _p1
９０90 _p4 , 110 _s1 １１０110 _s4 , 110 _p1 １１０110 _p4 ,
130 _{s1 to} 130 _s4 , 130 _{p1 to} 130 _p4 SAW resonator 11 to 13, 31 to 33, 51 to 53, 71 to 73, 9
1-93, 111-113, 131-133 Bonding pads 14, 34, 54, 74, 94, 114, 134 Connection patterns 15, 35, 55, 75, 95, 115, 135 Substrates 10a, 30a, 50a, 70a, 90a, 110a,
130a IDT 36,57,94,134 Al or Al alloy film 37,56,74,137 Au film 116,138 Dielectric film

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J097 AA24 AA25 AA26 AA29 BB02 BB11 CC02 DD25 DD29 FF03 GG03 HA02 HA04 JJ08 KK03 KK09

Claims (9)

[Claims] 1. A plurality of one-terminal pair surface acoustic wave resonators formed by depositing Al or an Al alloy serving as electrodes on a piezoelectric or ferroelectric single crystal substrate, and a plurality of bonding pads for external connection. A ladder-type surface acoustic wave filter in which the plurality of one-terminal-pair surface acoustic wave resonators are connected in a ladder-like manner between the plurality of bonding pads by a connection pattern. The connection pattern to be connected, the connection pattern to connect between the one-terminal pair surface acoustic wave resonator and the bonding pad, and the bonding pad are formed by being deposited on the piezoelectric or ferroelectric single crystal substrate. It is characterized in that at least one heat dissipation film made of a metal having higher thermal conductivity than the Al or Al alloy is laminated on the Al or Al alloy film. Ladder type surface acoustic wave filter to. 2. A plurality of one-terminal pair surface acoustic wave resonators each formed by depositing Al or an Al alloy serving as an electrode on a piezoelectric or ferroelectric single crystal substrate and a plurality of bonding pads for external connection. A ladder-type surface acoustic wave filter in which the plurality of one-terminal-pair surface acoustic wave resonators are connected in a ladder-like manner between the plurality of bonding pads by a connection pattern. The connection pattern to be connected, the connection pattern to connect between the one terminal pair surface acoustic wave resonator and the bonding pad, and the bonding pad are deposited in one or more layers on the piezoelectric or ferroelectric single crystal substrate. The film is formed by laminating the Al or Al alloy film on a metal film formed and having a higher thermal conductivity than the Al or Al alloy. Child-type surface acoustic wave filter. 3. A plurality of one-terminal pair surface acoustic wave resonators, each formed by depositing Al or an Al alloy serving as an electrode on a piezoelectric or ferroelectric single crystal substrate, and a plurality of bonding pads for external connection. A ladder-type surface acoustic wave filter in which the plurality of one-terminal-pair surface acoustic wave resonators are connected in a ladder-like manner between the plurality of bonding pads by a connection pattern. The connection pattern to be connected, the connection pattern to connect between the one terminal pair surface acoustic wave resonator and the bonding pad, and the bonding pad are deposited in one or more layers on the piezoelectric or ferroelectric single crystal substrate. A ladder type surface acoustic wave filter formed of a metal film having a higher thermal conductivity than the Al or Al alloy. 4. A plurality of one-terminal pair surface acoustic wave resonators, each formed by depositing Al or an Al alloy serving as an electrode on a piezoelectric or ferroelectric single crystal substrate, and a plurality of bonding pads for external connection. A ladder-type surface acoustic wave filter in which the plurality of one-terminal-pair surface acoustic wave resonators are connected in a ladder-like manner between the plurality of bonding pads by a connection pattern. The connection pattern for connection, the connection pattern for connecting the one-terminal pair surface acoustic wave resonator and the bonding pad, and the bonding pad are formed by being deposited on the piezoelectric or ferroelectric single crystal substrate, A ladder-type surface acoustic wave filter comprising a film of Al or an Al alloy that is 50% or more thicker than an electrode. 5. A plurality of one-terminal pair surface acoustic wave resonators formed by depositing Al or an Al alloy serving as electrodes on a piezoelectric or ferroelectric single crystal substrate, and a plurality of bonding pads for external connection. A ladder-type surface acoustic wave filter in which the plurality of one-terminal-pair surface acoustic wave resonators are connected in a ladder-like manner between the plurality of bonding pads by a connection pattern. The connection pattern to be connected, the connection pattern to connect between the one-terminal pair surface acoustic wave resonator and the bonding pad, and the bonding pad are formed by being deposited on the piezoelectric or ferroelectric single crystal substrate. It is characterized in that one or more dielectrics having higher thermal conductivity than the piezoelectric or ferroelectric single crystal substrate are laminated on an Al or Al alloy film. That ladder-type surface acoustic wave filter. 6. A plurality of one-terminal pair surface acoustic wave resonators formed by depositing Al or an Al alloy serving as electrodes on a piezoelectric or ferroelectric single crystal substrate and a plurality of bonding pads for external connection. A ladder-type surface acoustic wave filter in which the plurality of one-terminal-pair surface acoustic wave resonators are connected in a ladder-like manner between the plurality of bonding pads by a connection pattern. The connection pattern to be connected, the connection pattern to connect between the one terminal pair surface acoustic wave resonator and the bonding pad, and the bonding pad are deposited in one or more layers on the piezoelectric or ferroelectric single crystal substrate. One layer of a dielectric film having a higher thermal conductivity than the piezoelectric or ferroelectric single crystal substrate is formed on a metal film having a higher thermal conductivity than the Al or Al alloy. Ladder type surface acoustic wave filter characterized in that the arrangement overlaid above. 7. The dielectric having a higher thermal conductivity than the piezoelectric or ferroelectric single crystal substrate is made of Al ₂ O ₃ , AIN or Si ₃ N _4. Ladder type surface acoustic wave filter. 8. The method according to claim 1, wherein the Al alloy is obtained by adding Cu, Ti or Ta to Al.
The ladder-type surface acoustic wave filter according to 2, 3, 4, 5, 6, or 7. 9. The ladder according to claim 1, wherein the metal having a higher thermal conductivity than Al or an Al alloy is made of Au, Ag, or Cu. Type surface acoustic wave filter.