JPH05160664A - Surface acoustic wave element, its production, and surface acoustic wave device - Google Patents

Abstract

PURPOSE:To improve out-band supression and insertion loss by providing an inter-input electrode connection line and an inter-output electrode connection line between an ground-side terminal part and an input signal line. CONSTITUTION:In a surface acoustic wave element having a multi-electrode constitution provided with plural comb-shaped input electrodes 36, plural comb- shaped output electrodes 37, and comb-shaped ground electrodes 50, 51 for comb-shaped input/output electrodes 36 and 37, first ground-side terminal part 42 facing the input electrodes 36 are formed in ground electrodes 50 of input electrodes 36. Second ground-side terminal parts 45 facing the output electrodes 37 are formed in ground electrodes 51 of output electrodes 37. An input-side connection line 41 connecting ground electrodes is formed between the second connection terminal part 54 and an input signal line 43. An output-side connection line 44 connecting ground electrodes 51 is formed between the ground-side terminal part 45 formed in the ground electrode 51 of the input electrode 37 and an output signal line 46.

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 element, a method of manufacturing the same, and a surface acoustic wave device. A method and a surface acoustic wave device.

In recent years, various communication devices such as in-vehicle and portable telephones of 800 MHz band have been reduced in size and weight, and along with this, surface acoustic wave devices have been used as high frequency band filters. There is.

The surface acoustic wave device used in this type of communication device is required to have characteristics such as low loss, wide band, and excellent suppression degree.

Therefore, a surface acoustic wave device capable of realizing these various characteristics is desired.

[0005]

2. Description of the Related Art A surface acoustic wave device (eg, surface acoustic wave filter) is a piezoelectric substrate having a large electro-mechanical coupling coefficient and a relatively small temperature coefficient of frequency, such as 36 °.
Rotating Y-cut-X propagation LiTaO ₃ (36 ° YX LiTaO ₃ ) single-crystal substrate with three terminals or four provided with interdigital (comb-shaped) electrodes for input and output made of aluminum (Al) or the like. It is a terminal element.

[0006] Many of the usual surface acoustic wave devices have a structure in which a pair of input and output comb electrodes are opposed to each other, but depending on the application, low loss (for example, in the field of automobile phones and mobile phones) (for example, , Insertion loss: 3-5 dB or less, wide band (eg, center frequency: 836 MHz or more, pass band width: 2
5MHz or more, excellent suppression (eg out-of-band attenuation: 24)
Surface acoustic wave devices are being demanded.

[0007] Various methods have been provided to satisfy such performance, and a typical example thereof is a multi-electrode surface acoustic wave device (for example, M. Lewis, 198).
2 Ul-trasonics SymposiumProceedings, P12).

A problem in manufacturing the filter as described above is that the comb-shaped electrode is destroyed by the discharge due to the pyroelectric effect peculiar to the piezoelectric substrate. The surface acoustic wave device has a feature that a large number of wafers can be manufactured from one wafer similarly to the semiconductor process, but has a drawback that the yield is lowered due to electrode destruction due to pyroelectricity.

As a method for preventing the electrode destruction due to this pyroelectricity, Japanese Patent Application No. 2-95532 previously filed by the present applicant is proposed.
There is a "method for manufacturing a surface acoustic wave element" disclosed in.

FIGS. 9A and 9B are views for explaining the manufacturing method according to the same application. As shown in the figure, in the above-described manufacturing method, in the wafer processing step, the outermost surface of each of the surface acoustic wave devices 2 in the surface acoustic wave device 2 is adjusted so that all the conductor patterns formed on the surface of the piezoelectric wafer 1 have the same potential. It is characterized in that a connection line 6 connecting the ground-side electrode fingers 3 and 4 and a plurality of connection lines 8 connecting each electrode formed on the surface acoustic wave device 2 to a scribe line 7 are formed. In the figure, 9 is a comb-shaped input electrode, 10 is a comb-shaped output electrode, and 11 is a reflector.

With the above manufacturing method, all the conductor patterns formed on the surface of the piezoelectric wafer 1 are connected until the piezoelectric wafer 1 is cut along the scribe lines 7 to form individual chips. Since it is connected to the scribe line 7 via the lines 6 and 8, all the conductor patterns have the same potential. Therefore, even if electric charges are generated due to the pyroelectric effect due to the temperature change of the heat treatment character required in the manufacturing process, the electric charges are immediately neutralized and a high voltage is generated between the electrode conductor patterns to discharge. Disappears
It is possible to prevent the occurrence of electrode breakage.

On the other hand, another problem of the surface acoustic wave device having the multi-stage electrode structure is that the out-of-band suppression degree deteriorates due to the influence of the magnetic field due to the loop current and the direct wave due to the capacitive coupling between the input and output electrodes. As a conventional technique for solving this problem, there is one disclosed in Japanese Patent Laid-Open No. 19415/1993.

In the surface acoustic wave device disclosed in Japanese Patent Laid-Open No. 3-19415, two or more input electrodes and three or more output electrodes for transmitting and receiving surface acoustic waves are arranged on the same propagation path. And, the wiring by the wire from the ground electrode of the input electrode or the wiring by the extension of the electrode pattern,
Connect to the metal stem on the input stem lead pin side of the input electrode for grounding, and connect the wiring from the ground electrode of the output electrode to the metal stem on the output stem lead pin side of the output electrode or the wiring by extending the electrode pattern to the ground. It is a configuration.

The surface acoustic wave device having the above structure is
To cancel the magnetic field generated on the signal source electrode side and the magnetic field generated on the ground electrode side by returning the ground wiring of the ground electrode of the input / output electrode to the respective stem lead pin side by a wire or an electrode pattern. Therefore, the mutual induction effect can be reduced, and the capacitive coupling between the input and the output can be reduced by separating the ground electrodes of the input / output electrodes.

[0015]

However, when a high-frequency filter in the 2.6 GHz band is manufactured by the "method for manufacturing a surface acoustic wave element" disclosed in Japanese Patent Application No. 2-95532, it can be manufactured with high yield. , The out-of-band suppression is about 10dB worse than the 800MHz band filter.

Further, in the surface acoustic wave device disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-19415, although the out-of-band suppression degree can be improved, resistance is generated in the common lines for input and output, so that There is a problem that the loss at high frequency becomes large due to the effect of this resistance loss.

The above problem will be further described with reference to FIGS. Further, in each drawing, (A) shows the comb-shaped electrode forming portion constituting the surface acoustic wave device in an enlarged manner, and (B) shows an equivalent circuit of each surface acoustic wave device.

FIG. 10 shows a surface acoustic wave device manufactured by the "method for manufacturing a surface acoustic wave element" disclosed in Japanese Patent Application No. 2-95532. In the figure, 15 is an input side electrode, 16 is an output side electrode, and 17 is a common ground electrode common to the input and output side electrodes. Further, in the figure, reference numeral 18 is a comb-shaped electrode forming portion on the input side, and 19 is a comb-shaped electrode forming portion on the output side. In addition, as shown in FIG.
A connection line 6 is provided between the outermost ground-side electrode fingers 3 and 4 in FIG.
It is connected to the.

However, in the configuration shown in FIG. 10, the resistance and stray capacitance of the comb-shaped electrode forming portions 18 and 19 between the surface acoustic wave device and the ground of the stem on which the surface acoustic wave device is mounted are shown in FIG. , The impedances Z _a and Z
_b will be formed. In the configuration of this example, since the high frequency voltage V ₀ is shared between the input and the output, V ₀ is also transmitted even at the frequency at which the surface acoustic wave does not propagate in the stop band region, so that the out-of-band suppression degree deteriorates.

On the other hand, FIG. 11 shows a surface acoustic wave device disclosed in Japanese Unexamined Patent Publication No. 3-19415. In the figure, 20 is an input side electrode, 21 is an output side electrode, 22
Is a ground electrode on the input side, and 23 is a ground electrode on the output side.
Further, in the figure, 24 is a comb-shaped electrode forming portion on the input side, and 25
Is a comb-shaped electrode forming portion on the output side. In this example, the ground electrode 24 on the input side and the ground electrode 23 on the output side are independent.

In the surface acoustic wave device configured as described above, since the input and output ground electrodes 22 and 23 are separated from each other, there is no stray capacitance, and the impedance is only the resistance of the electrodes, so the out-of-band suppression is improved. it can.

However, in the above-mentioned surface acoustic wave device,
Since the ground electrodes 22 and 23 are configured to be bonded to the stem from above the common connection line, there is a problem in that loss is deteriorated due to the resistance of the common connection line.

This will be specifically described by taking the ground electrode 22 as an example. In order to ground the ground electrode 22, the ground electrode 2
2, bonding pads 22a-1 and 22a-2 (only two bonding pads are shown in the figure) are formed.
A wire 26 is bonded between 2a-2 and the stem (not shown).

Therefore, the comb-shaped ground electrode 22 of the comb-shaped electrode forming portion 24 on the input side is bonded to the bonding pads 22a-1 and 22a through the common connection lines 27 and 28 (shown as a satin in the figure).
-Connected to 2. In this way, the comb-shaped ground electrode 22 is disposed between the pair of bonding pads 22a-1 and 22a-2, and the comb-shaped ground electrode 22 and the bonding pad 22 are provided.
Since the common connection lines 27 and 28 that connect the a-1 and 22a-2 are thin, the resistance (indicated by r _a and r _b in the same figure (B)) is high,
Due to the resistance of the common connection lines 27 and 28, loss is deteriorated.

Further, the surface acoustic wave device described above has a problem that the yield of the surface acoustic wave device is poor because no countermeasure against pyroelectricity is taken.

The present invention has been made in view of the above points, and an object of the present invention is to provide a surface acoustic wave element, a method of manufacturing the same, and a surface acoustic wave device, in which out-of-band suppression and insertion loss are improved. ..

[0027]

Means for Solving the Problems The above-mentioned problem is to provide a plurality of comb-shaped input electrodes connected to input signal lines and a plurality of comb-shaped output electrodes connected to output signal lines on a piezoelectric substrate. ,
The comb-shaped ground electrode of the comb-shaped input electrode and the comb-shaped ground electrode of the comb-shaped output electrode are arranged such that the comb-shaped electrodes are alternately spaced and opposed to each other and are aligned in a meshed state. In a surface acoustic wave device having a multi-electrode structure in which electrodes and comb-shaped output electrodes are alternately arranged, a first ground-side terminal portion is provided on a comb-shaped ground electrode of the comb-shaped input electrode so as to face the comb-shaped input electrode. And a second ground-side terminal portion is formed on the comb-shaped ground electrode of the comb-shaped output electrode so as to face the comb-shaped output electrode, and the comb-shaped ground electrode of the comb-shaped input electrode is formed. An output connecting the input-side ground electrode connecting line to be connected at least at a position between the second ground-side terminal portion and the input signal line, and connecting the comb-type ground electrode of the comb-type output electrode. At least the comb-shaped ground of the comb-shaped input electrodes should be connected It can be solved by the surface acoustic wave device characterized by being formed at a position between the output signal line and the ground-side terminal portion formed on the pole.

Further, on the surface of the piezoelectric wafer, at least a plurality of comb-shaped input electrodes connected by input signal lines, and a plurality of comb-shaped output electrodes connected by output signal lines,
The comb-shaped input electrodes and the comb-shaped ground electrodes of the comb-shaped output electrodes are arranged so that the comb-shaped electrodes are alternately opposed and spaced from each other and are aligned in a meshed state, and the comb-shaped input electrodes and the comb-shaped output electrodes are arranged. Wafer processing step of forming a large number of alternately arranged multi-electrode surface acoustic wave elements with a scribe line made of a metal film as a boundary, and individual element formation of cutting the piezoelectric wafer along the scribe line In a method of manufacturing a surface acoustic wave device having a multi-electrode structure including at least a step, a first ground-side terminal portion is formed on a comb-shaped ground electrode of the comb-shaped input electrode so as to face the comb-shaped input electrode, Also, a second ground-side terminal portion is formed on the comb-shaped ground electrode of the comb-shaped output electrode so as to face the comb-shaped output electrode, and an input for connecting the comb-shaped ground electrode of the comb-shaped input electrode. Reduce the number of connecting wires between the side ground electrodes. At least the inter-output-side-ground-electrode connection line that is formed at a position between the second ground-side terminal portion and the input signal line and that connects the comb-shaped ground electrodes of the comb-shaped output electrodes is at least the comb. Is formed at a position between the ground-side terminal portion formed on the comb-shaped ground electrode of the mold input electrode and the output signal line, and further, all conductor patterns on the surface of the piezoelectric wafer in the wafer processing step have the same potential. A method for manufacturing a surface acoustic wave device, characterized in that a plurality of inter-scriber-line connecting lines for connecting at least the comb-shaped input electrode, the comb-shaped output electrode, and the comb-shaped ground electrode to the scribe line are formed so that Can be solved by.

Further, the surface acoustic wave device according to claim 1 is
In a surface acoustic wave device housed in a package having a metal pattern formed therein, the surface acoustic wave device is formed on the first or second ground side terminal portion and the input signal line and the output signal line. A metal bump is formed on the signal terminal portion, a ground metal pattern is formed in a comb shape on the cover plate or bottom plate of the package, and the metal bump and the ground metal pattern are contact-connected. It can be solved by a surface acoustic wave device.

Further, in the surface acoustic wave element according to claim 1, a first auxiliary terminal portion is formed outside the output signal line so as to face the first ground side terminal portion, and The first ground-side terminal portion and the first auxiliary terminal portion are connected in an air bridge shape across the output signal line by the first metal film, and the first and second auxiliary terminal portions are connected to the outside of the input signal line by the first metal film. The second auxiliary terminal portion is formed so as to face the second ground-side terminal portion, and the second ground-side terminal portion and the second auxiliary terminal portion are formed of a second metal film to form the input signal line. The surface acoustic wave device is characterized in that it is connected in the form of an air bridge straddling each other, and the problem can be more effectively solved.

In addition, in a surface acoustic wave device in which the surface acoustic wave element according to claim 4 is housed in a package in which a metal pattern is formed, the first surface acoustic wave element can be used.
And a second metal film, metal bumps formed on the signal terminal portion of the input signal line and the signal terminal portion of the output signal line, and the metal pattern formed on the lid plate or the bottom plate of the package and the metal pattern. This can be solved by a surface acoustic wave device characterized by being contact-connected with a metal bump.

[0032]

According to the present invention, since the inter-input electrode connecting line and the output electrode connecting line are formed between the ground side terminal portion and the input signal line, impedance due to both stray capacitance and resistance is reduced to zero. Therefore, the band suppression and loss can be improved.

Further, metal bumps are formed on the ground side terminal portion, the input signal line and the signal terminal portion formed on the input signal line, and the metal bump and the comb-shaped grounding metal pattern formed on the package are formed. By the contact connection, the wiring for input and its ground and the wiring for output and its ground are formed in the same direction, so that the electromagnetic field generated between each wiring can be canceled. Moreover, since it is not necessary to use the wire bonding method, it is possible to extremely easily connect the elements and to downsize the surface acoustic wave device.

[0034]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 2 is a diagram showing a multi-element forming wafer having the surface acoustic wave element 30 according to the first embodiment of the present invention. In the figure, 31 is a piezoelectric wafer, for example, 36 ° rotation Y cut-X propagation LiTaO _{3 having a} thickness of 0.5 mm and a diameter of 51 mm.
(36 ° Y-XLiTaO ₃ ) Single crystal substrate, surface acoustic wave device 3
0 has a structure in which an electrode group is formed in a portion shown by a broken line in the drawing.

A scribe line 33 is a boundary line between the surface acoustic wave elements 30 and is made of the same metal as the electrodes, for example, an aluminum (Al) -copper (Cu) alloy. The scribe line 33 is connected to a metal film 34 (indicated by diagonal lines in the figure) made of Al—Cu and formed at the same time as the electrodes on the periphery of the wafer. 35a to 35e are connection lines between scribe lines (hereinafter, simply referred to as connection lines), which are surface acoustic wave elements 30.
Each of the essential points of the electrode of (3) is connected to the scribe line 33.

FIG. 1 is an enlarged view showing an electrode arrangement of a surface acoustic wave element 30 which is an embodiment of the present invention. Also,
The figure shows a state before the surface acoustic wave element 30 is cut out into individual chips.

In the figure, 36 is a comb-shaped input electrode and 37
Is a comb-shaped output electrode, 38 is a reflector, and 50 is a comb-shaped input electrode 3.
The comb-shaped ground electrodes 6 and 51 are the comb-shaped ground electrodes of the comb-shaped output electrode 37, and these electrodes are formed together with the scribe line 33 and the connection lines 35a to 35e by an Al-Cu sputtered film.

In the surface acoustic wave device 30 of this embodiment, in order to obtain the center frequency of 2.6 GHz, the thickness of the sputtered film of Al-Cu is 700Å, the electrode finger period is 1.6 μm, the electrode finger width and the electrode finger spacing are The thickness is 0.4 μm, and a pattern is formed in a desired shape by the electron beam exposure method and the usual etching method. The electrode configuration has 7 inputs and 6 outputs, and the number of pairs of electrode fingers is 40 pairs on the input side and 60 pairs on the output side, both of which are normal types. The number of electrode finger pairs of the reflector 38 is 40, which is an open strip type in which the load is electrically opened.

Here, in FIG. 3A, the comb-shaped input electrodes 36,
The comb-shaped output electrode 37 is further enlarged and shown, and the pattern shape of each electrode will be described with reference to FIG.

As shown in each figure, the comb-shaped ground electrode 50 is provided.
The ground-side terminal portion 42 integrally formed with the comb-shaped input electrode 36 is formed at a position facing the comb-shaped input electrode 36, and the ground-side terminal portion 45 integrally formed with the comb-shaped ground electrode 51 is a comb-shaped output electrode. It is formed at a position facing the electrode 37.

The plurality of comb-shaped input electrodes 36 are connected to each other by an input signal line 43, and an input terminal 47 is formed at a predetermined position of the input signal line 43.
Further, the plurality of comb-shaped output electrodes 37 are connected to each other by an output signal line 46, and an output terminal 48 is formed at a predetermined position of the output signal line 46.

On the other hand, reference numeral 41 denotes an input side ground electrode connecting line (hereinafter referred to as an input side connecting line) connecting the outermost ground electrode finger 40 of the electrode finger group of the comb type ground electrode 50, which is at least comb-shaped. It is formed in the gap between the ground-side terminal portion 45 of the output electrode 37 and the input signal line 43. Further, reference numeral 44 denotes an output side ground electrode connecting line (hereinafter referred to as an output side connecting line) connecting the outermost ground electrode finger 39 of the electrode finger group of the comb type ground electrode 51, and at least the comb output electrode 36. Is formed in the gap between the ground side terminal portion 42 and the output signal line 46.

The input side connecting line 41 and the output side connecting line 44 are both formed of Al--Cu, like other electrodes, and are formed at the same time when the other electrodes are formed. Further, the input and output connection lines 41, 44 are connected to the ground side terminal portions 42, 45.
Since it is formed in the gap between the input / output signal lines 43 and 46, its width is small, but each comb-shaped ground electrode 50,
Grounded terminal portions 42 and 45, which are grounded, are integrally formed at 51. Therefore, the impedance due to both the stray capacitance and the resistance of the input and output connection lines 41 and 44 can be substantially reduced to zero, so that the out-of-band suppression and the loss can be improved. 3B shows an equivalent circuit of the surface acoustic wave device 30 shown in FIGS. 1 and 3A.

On the other hand, in the figure, reference numerals 35a to 35e are connection lines connecting the respective essential points of the electrodes of the surface acoustic wave element 30 to the scribe line 33, as described above. Specifically, the connection lines 35a and 35b connect the input terminals 47 and 48 to the scribe line 33, the connection lines 35c and 35d connect the comb-shaped ground electrodes 50 and 51 to the scribe line 33, and further the connection lines 35e and 35e. 35f is a reflector 38 and a scribe line 33
Connected to. Each of the connection lines 35a to 35e is also made of Al-Cu similarly to the other electrodes, and is formed at the same time when the other electrodes are formed.

As described above, the connection terminals 35a to 35e are used to form the input terminal 4 which is a key part of the electrode of the surface acoustic wave element 30.
7, 48 (that is, the comb-shaped input electrode 36, the comb-shaped output electrode 3
7), the comb-shaped ground electrodes 50, 51 and the reflector 38 are connected to the scribe line 33. With this configuration, all the electrode patterns formed on the piezoelectric wafer 31 are electrically connected and have the same potential during the manufacturing process of the piezoelectric wafer 31. Therefore, even if electric charges based on the pyroelectric effect are generated due to a temperature change due to the heat treatment performed during the manufacturing process, the generated electric charges are immediately neutralized and a high voltage is generated between the electrode patterns to discharge. This can prevent the destruction of the electrode without fail.

The piezoelectric wafer 31 having the above-mentioned structure is manufactured by the wafer processing step. When the wafer processing step is completed, the individual element forming step is carried out, and the piezoelectric wafer 3 is formed.
1 is cut along the scribe line 33 by a cutting machine having a diamond blade that is thicker than the width of the scribe line 33 having a width of 50 μm, for example.

By performing this individual element forming step, the surface acoustic wave element 30 is obtained as another element, so-called a filter chip, and the cutting width of the diamond blade is 80 to 100 μm. 33 is removed, and the essential parts of the electrodes are electrically opened. As a result, the surface acoustic wave device 30 having a multi-electrode structure according to the present invention is created, and the input / output electrodes 36, 37 and the ground electrodes 50, 51 can be separated from each other.

The surface acoustic wave element 30 thus produced is housed in a package, and a predetermined connection process (each terminal portion 42, 45, 47, 48 of the surface acoustic wave element 30 is used as a lead arranged on the package). The step of connecting is performed, and the surface acoustic wave device is manufactured.

In the connection step, in order to reduce the interaction of the electromagnetic fields, the comb-shaped input electrode 36 and its ground electrode 50, and the comb-shaped output electrode 37 and its ground electrode 51 are arranged in the same direction. Then, the current loops may be canceled each other. As described above, there is a method of using wire bonding as a means for performing wiring (see Japanese Patent Laid-Open No. 3-19415). However, this method uses a resistance difference due to the influence of the wire length or a wire short circuit in the aerial wiring portion. For example, when it is used as a filter, there arises a problem that the reproducibility of the filter characteristic is lowered or the manufacturing yield of the filter device is lowered. Less than,
A surface acoustic wave device that can solve the above problems will be described.

FIG. 4 is a diagram showing a second embodiment of the present invention, and FIGS. 4 (a) to 4 (e) show an outline of the surface acoustic wave device 30, the package and the packaging in order.

FIG. 9A is a plan view of the surface acoustic wave element 30, and FIG. 9B is a sectional view taken along line XX in FIG.
A cross section along the line is shown, and FIG. 6C shows a cross section along the line YY in FIG.

In each figure, 60 is a metal bump provided on the input terminal 47, 61 is a metal bump provided on the output terminal 48, 62 is a metal bump provided on the output side ground side terminal portion 45, and 63 is a metal bump. The metal bumps are provided on the ground-side terminal portion 42 on the input side, and are both formed of, for example, gold (Au).

FIG. 9D is a rear view of the lid plate 64 of the package, and FIG. 8E shows a cross section taken along line YY in FIG. The lid plate 64 is made of, for example, a ceramic substrate, and has an input metal pattern 65, an output metal pattern 66, and comb-shaped grounding metal patterns 67 and 68 each made of an Au film. At this time, the output side grounding metal pattern 67 connected to the metal bumps 62 provided on the output side ground side terminal portion 45 and the metal bumps 63 provided on the input side ground side terminal portion 42 are connected. The metal patterns 68 for grounding on the input side are arranged so as to be alternately opposed to each other in a meshed state and aligned with each other.

FIG. 6F is a sectional view of a surface acoustic wave device 70 in which a surface acoustic wave element 30 is sealed in a package. The surface acoustic wave device 70 includes the surface acoustic wave element 30 on the bottom surface of a package container 69 made of, for example, ceramic.
After die-bonding, the lid plate 64 having the above-mentioned configuration
Of the metal bumps 6 formed on the surface acoustic wave element 30 by rotating 180 degrees with respect to the Y-Y axis shown in FIG.
0-63 and each metal pattern 65 formed on the cover plate 64
68 is contact-connected.

Subsequently, for example, by heating and pressing, the metal bumps 60 to 63 and the metal patterns 65 to 68 are electrically connected, and at the same time, the peripheral portion of the cover plate 64 and the package container 6 are connected.
The upper edge of 9 is bonded with metal or resin (not shown) to form the surface acoustic wave device 70. Note that, for simplification of the drawing, the lead terminals outside the package are not shown.

As is clear from each figure, by forming the grounding metal patterns 67 and 68 formed on the cover plate 64 in a comb shape, the comb-shaped input electrode 36 and the grounding side input metal pattern of the grounding are formed. 68 and the comb-shaped output electrode 37 and the output side grounding metal pattern 67 for grounding the comb-shaped output electrode 37 are formed in the same direction, so that the magnetic field generated between each electrode finger and the metal patterns 67, 68 can be canceled out, and the elastic surface Wave device 7
It is possible to improve the characteristics of 0. Further, in the above configuration, since the wire bonding method is not used, the connection between the surface acoustic wave element 30 and each of the metal patterns 65 to 68 can be extremely simplified, the manufacturing process can be simplified, and the elastic surface can be realized. The wave device 70 can be downsized.

FIG. 5 is an exploded perspective view showing a surface acoustic wave device 80 which is a modification of the surface acoustic wave device 70 shown in FIG. In the surface acoustic wave device 70 shown in FIG. 4, each metal bump 6 formed on the surface acoustic wave element 30.
Although the metal patterns 65 to 68 connected to 0 to 63 are formed on the lid plate 64, the present modification is characterized in that the metal patterns 65 to 68 are formed on the bottom plate 82 constituting the package 81. It is a thing. Note that, in FIG. 5, the same reference numerals are given to the components corresponding to those of the surface acoustic wave device 70 shown in FIG.

In FIG. 5, reference numeral 82 is a ceramic bottom plate, 83 is a metal cover plate (a metal pattern is not formed on the cover plate 83), and 84 is a ceramic frame body. Each of the metal bumps 60 to 63 formed on the element 30 has a metal pattern 85 formed on the bottom plate 82.
To 88. Among these metal patterns 85 to 88, the output side grounding metal pattern 87 connected to the metal bumps 62 provided on the output side grounding side terminal portion and the metal bumps provided on the input side grounding side terminal portion. The input-side grounding metal pattern 88 connected to 63 is disposed so as to be alternately spaced and opposed to each other and aligned in a meshed state.

Therefore, the surface acoustic wave device 8 of this embodiment is used.
Also in 0, the electrode fingers of the comb-shaped input electrode 36, the input-side grounding metal pattern 88 for grounding the electrode fingers, and the comb-shaped output electrode 37.
Since the electrode fingers of and the grounding output side metal pattern 87 are formed in the same direction, the magnetic field generated between each electrode finger and the metal patterns 87 and 88 can be canceled and the characteristics of the surface acoustic wave device 80. It is possible to improve. Further, in the above configuration, since the wire bonding method is not used, the connection between the surface acoustic wave element 30 and each of the metal patterns 85 to 88 can be extremely simplified, the simplification of the manufacturing process can be realized, and the elastic surface can be realized. The wave device 80 can be downsized.

6A and 6B are views showing a third embodiment of the present invention. FIG. 6A is a plan view and FIG. 6B is a sectional view taken along the line YY in FIG. 6A. Is shown. Further, in each drawing, the same components as those of the surface acoustic wave element 30 shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the surface acoustic wave element 90 according to this embodiment, an auxiliary terminal portion 91 corresponding to the input side ground side terminal portion 42 is formed on the piezoelectric wafer 31, and the output side ground side terminal portion 45 is formed. An auxiliary terminal portion 92 corresponding to is formed. Further, the auxiliary terminal portion 91 on the input side is provided with the input signal line 4
3 is formed on the outer side position (position close to the scribe line 33), and the auxiliary terminal portion 92 on the output side is provided with the output signal line 4
It is arranged at an outer position of 6. Each of these auxiliary terminal parts 9
1, 92 are made of Al-Cu, like other electrode materials.

A metal thin film 93 is formed between the ground-side terminal portion 42 on the input side and the auxiliary terminal portion 91, and both terminals 4
2, 91 are electrically connected to each other, and a metal thin film 94 is formed between the grounding side terminal portion 45 on the output side and the auxiliary terminal portion 92 to electrically connect both terminals 45, 92. .. The metal thin films 93 and 94 connect the terminals 42 and 91 and the terminals 45 and 92 in an air bridge shape, as shown in FIG. Therefore, each metal thin film 9
3, 94 have no effect on the comb-shaped input / output electrodes 36, 37 and the comb-shaped ground electrodes 50, 51 disposed therebelow.

In the surface acoustic wave device 90 having the above structure, the input side ground side terminal portion 42 is pulled out to the side where the input terminal 47 is provided by the metal thin film 93, so that the auxiliary terminal portion 9 is provided.
By grounding 1, the ground terminal 42 on the input side can be grounded. Similarly, the ground terminal 45 on the output side can be grounded by grounding the auxiliary terminal 92.
Therefore, the input terminal 47 on the input side and the auxiliary terminal portion 91 can be collectively arranged on the same side of the surface acoustic wave element 90, and the output terminal 48 on the output side and the auxiliary terminal portion 92 can be arranged on the surface acoustic wave element. The terminals 90 can be collectively arranged on the side different from the arrangement position of the input side terminals. This facilitates electrical connection between each terminal and the metal pattern formed on the package, and the package for accommodating the surface acoustic wave element 90 can be miniaturized.

FIG. 7 is a diagram showing a fourth embodiment of the present invention, and FIGS. 7 (a) to 7 () show the surface acoustic wave device 90, the package and the outline of the packaging in order.

FIG. 9A is a plan view of the surface acoustic wave element 90, and FIG. 9B is a sectional view taken along line XX in FIG.
A cross section along the line is shown, and FIG. 6C shows a cross section along the line YY in FIG. still,
In each drawing, the same components as those shown in FIGS. 4 and 6 are designated by the same reference numerals and the description thereof will be omitted.

In each drawing, 101 is a metal bump provided on the input terminal 47, 102 is a metal bump provided on the output terminal 48, 103 is a metal bump provided on the input-side metal thin film 93, and 104 is an output side. Are metal bumps provided on the metal thin film 94, and are formed of, for example, gold (Au).

FIG. 9D is a rear view of the lid plate 105 of the package, and FIG. 8E is YY in FIG.
The cross section along the line is shown. The lid plate 105 is made of, for example, a ceramic substrate, and has an input metal pattern 106, an output metal pattern 107, and grounding metal patterns 108 and 109 each made of an Au film. On this occasion,
Unlike the comb-shaped grounding metal patterns 67 and 68 shown in FIG. 4, the grounding metal patterns 108 and 109 are not formed in a comb shape, and have a predetermined width in the longitudinal side edge portion of the lid plate 105. It is formed with dimensions.

FIG. 6F is a sectional view of a surface acoustic wave device 100 in which a surface acoustic wave element 90 is sealed in a package. In the surface acoustic wave device 90, for example, after the surface acoustic wave element 90 is die-bonded to the bottom surface of the package container 110 made of ceramic, the lid plate 105 having the above-described configuration is placed on the YY axis shown in FIG. The metal bumps 101 to 104 formed on the surface acoustic wave element 90 and the metal patterns 106 to 109 formed on the cover plate 105 are contact-connected with each other by rotating 180 degrees.

Subsequently, for example, by heating and pressing, the metal bumps 101 to 104 and the metal patterns 106 to 109 are electrically connected, and at the same time, the peripheral portion of the lid plate 105 and the upper edge portion of the package container 110 are made of metal. Alternatively, the surface acoustic wave device 100 is formed by bonding with a resin (not shown). Note that, for simplification of the drawing, the lead terminals outside the package are not shown.

The surface acoustic wave device 100 according to this embodiment.
Since the surface acoustic wave element 90 having the electrode pattern shown in FIG. 6 is used, the characteristics of the surface acoustic wave device 100 can be improved. That is, the surface acoustic wave element 9
0 indicates the ground side terminal portion 42 at the upper position of the comb-shaped input electrode 36.
The metal thin film 93 connected to the above is arranged in the shape of an air bridge, and the metal thin film 94 connected to the ground side terminal portion 45 is arranged in the shape of an air bridge at the upper position of the comb-shaped output electrode 37. Therefore, the metal thin films 93, 94
Are arranged in a comb shape as shown in FIG. 6 (A).

Therefore, the electrode fingers of the comb-shaped input electrode 36 and the metal thin film 93 for grounding the same are formed in the same direction, and the electrode fingers of the comb-shaped output electrode 37 and the metal thin film 94 for grounding are formed in the same direction. The magnetic field generated between each electrode finger and each of the metal thin films 93 and 94 can be canceled, and the characteristics of the surface acoustic wave device 100 can be improved. Further, even in the above configuration, since the wire bonding method is not used, the surface acoustic wave element 9
The connection between 0 and each of the metal patterns 106 to 109 can be extremely simplified, the manufacturing process can be simplified, and the surface acoustic wave device 100 can be downsized.

FIG. 8 shows a surface acoustic wave device 3 according to the present invention.
It is a figure which compares and shows the characteristics of 0 and 90 and the conventional surface acoustic wave element. In the figure, the solid line shows the characteristics of the surface acoustic wave elements 30 and 90 according to the present invention, and the broken line shows the characteristics of the conventional surface acoustic wave element disclosed in Japanese Patent Application Laid-Open No. 3-19415. Further, the alternate long and short dash line shows the characteristics of the surface acoustic wave device disclosed in Japanese Patent Application No. 2-95532. Further, the characteristics shown in the same figure show the pass characteristics of the bandpass filter in the 2.6 GHz band.

As shown in the figure, the surface acoustic wave elements 30 and 90 according to the present invention exhibit better characteristics than the characteristics of the conventional surface acoustic wave elements. −
With respect to the characteristics of the conventional surface acoustic wave element disclosed in Japanese Patent No. 19415, the out-of-band suppression degree can be improved by 10 dB, and the characteristics of the surface acoustic wave element disclosed in Japanese Patent Application No. 2-95532 can be improved. On the other hand, the insertion loss could be improved by 1 dB.

[0075]

As described above, according to the present invention, since the inter-input-electrode connecting line and the output-electrode connecting line are formed between the ground-side terminal portion and the input signal line, stray capacitance and resistance Since the impedance due to both can be zero, out-of-band suppression and loss can be improved.

Further, metal bumps are formed on the ground side terminal portion, the input signal line and the signal terminal portion formed on the input signal line, and the metal bump and the comb-shaped grounding metal pattern formed on the package are brought into contact with each other. By connecting, the wiring for input and its ground and the wiring for output and its ground are formed in the same direction respectively, so that the electromagnetic field generated between each wiring can be canceled out, and out-of-band suppression and deterioration of insertion loss are caused. Can be prevented. Moreover, since it is not necessary to use the wire bonding method, it is possible to extremely easily connect the elements and to downsize the surface acoustic wave device.

Further, a first auxiliary terminal portion is formed outside the output signal line so as to face the first ground side terminal portion, and the first ground side terminal portion and the first auxiliary terminal portion are provided. The first metal film is connected in an air bridge shape across the output signal line, and the second auxiliary terminal portion is formed outside the input signal line so as to face the second ground side terminal portion. With
The first metal film and the second metal film are formed by connecting the second ground side terminal portion and the second auxiliary terminal portion with the second metal film in an air bridge shape across the input signal line. Since it has a comb-like configuration, it is possible to cancel the electromagnetic field generated between the wirings and prevent deterioration of the out-of-band suppression and insertion loss.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram showing a piezoelectric wafer on which a large number of surface acoustic wave elements according to the present invention are formed.

FIG. 3 is an enlarged view showing an electrode of a surface acoustic wave device according to the present invention.

FIG. 4 is a diagram for explaining a second embodiment of the present invention.

FIG. 5 is a diagram for explaining a modification of the second embodiment of the present invention.

FIG. 6 is a diagram for explaining a third embodiment of the present invention.

FIG. 7 is a diagram for explaining a fourth embodiment of the present invention.

FIG. 8 is a diagram for explaining the effect of the present invention.

FIG. 9 is a diagram for explaining an example of a conventional surface acoustic wave element.

FIG. 10 is a diagram for explaining an example of a conventional surface acoustic wave element.

FIG. 11 is a diagram for explaining an example of a conventional surface acoustic wave element.

[Explanation of symbols]

 30, 90 Surface acoustic wave element 31 Piezoelectric wafer 33 Scribe line 34 Metal film 35a to 35e Connection line 36 Comb type input electrode 37 Comb type output electrode 38 Reflector 39, 40 Ground electrode finger 41 Input side connection line 42, 45 Ground Side terminal part 43 Input signal line 44 Output side connection line 47 Input terminal 48 Output terminal 50, 51 Comb type ground electrode 60-63, 101-104 Metal bump 64, 83, 105 Cover plate 65, 106 Input metal pattern 66 , 107 Output metal pattern 67, 68, 108, 109 Grounding metal pattern 69, 110 Package container 70, 80, 100 Surface acoustic wave device 81 Package 82 Bottom plate 84 Frame body 85-88 Metal pattern 91, 92 Auxiliary terminal portion 93 , 94 Metal thin film

Claims (5)

[Claims] 1. A plurality of comb-shaped input electrodes (36) connected to an input signal line (43) on a piezoelectric substrate (31),
A plurality of comb-shaped output electrodes (37) connected to the output signal line (46), a comb-shaped ground electrode (50) of the comb-shaped input electrode (36), and a comb of the comb-shaped output electrode (37). The comb-shaped electrodes and the comb-shaped input electrodes are alternately arranged so as to be spaced apart and face each other, and the comb-shaped input electrodes (36) and the comb-shaped output electrodes (37) are alternately arranged. In the arranged surface acoustic wave element having a multi-electrode structure, the comb-shaped ground electrode (50) of the comb-shaped input electrode (36) is
A first ground side terminal portion (42) is formed so as to face the comb-shaped input electrode (36), and the comb-shaped output electrode (3) is formed.
In the comb-shaped ground electrode (51) of 7), the comb-shaped output electrode (3)
7), the second ground side terminal portion 45 is formed, and the input side ground electrode connecting line 41 is connected to the comb ground electrode 50 of the comb input electrode 36. Is formed at least between the second ground side terminal portion (45) and the input signal line (43), and the comb-shaped ground electrode (5) of the comb-shaped output electrode (37) is formed.
The connection wire (44) between the output side ground electrodes for connecting (1) is connected to at least the comb ground electrode (5) of the comb input electrode (37).
A surface acoustic wave element, characterized in that it is formed at a position between the ground side terminal portion (45) formed in 1) and the output signal line (46). 2. A piezoelectric wafer (31) having at least a plurality of comb-shaped input electrodes (36) connected by an input signal line (43) and an output signal line (46) on the surface of the piezoelectric wafer (31). The plurality of comb-shaped output electrodes (37) and the comb-shaped ground electrodes (50, 51) of the comb-shaped input electrodes (36) and the comb-shaped output electrodes (37) are alternately opposed to each other and are aligned in a meshed state. And the comb-shaped input electrode (3
Wafer processing step of forming a large number of surface acoustic wave elements (30) having a multi-electrode structure in which 6) and comb-shaped output electrodes (37) are alternately arranged with a scribe line (33) made of a metal film as a boundary. And a method of manufacturing a surface acoustic wave device having a multi-electrode structure, which includes at least an individual element forming step of cutting the piezoelectric wafer (31) along the scribe line (33), the comb-shaped input electrode (36) On the comb-shaped ground electrode (50) of
A first ground side terminal portion (42) is formed so as to face the comb-shaped input electrode (36), and the comb-shaped output electrode (3) is formed.
The comb-shaped output electrode (3) is connected to the comb-shaped ground electrode (51) of 7).
The second ground-side terminal portion (45) is formed so as to be opposed to the comb-shaped input electrode (36).
And an input side ground electrode connecting line (41) for connecting 0) is formed at least at a position between the second ground side terminal portion (45) and the input signal line (43), and The comb-shaped ground electrode (5) of the output electrode (37)
The connection wire (44) between the output side ground electrodes for connecting (1) is connected to at least the comb ground electrode (5) of the comb input electrode (36).
0) formed between the ground side terminal portion (42) and the output signal line (46), and further, the piezoelectric wafer (3) in the wafer processing step.
1) Make sure that all conductor patterns on the surface have the same potential.
A plurality of inter-scriber line connecting lines (35a to 35e) for connecting at least the comb-shaped input electrode (36), the comb-shaped output electrode (37), and the comb-shaped ground electrode (50, 51) to the scribe line (33), respectively. A method of manufacturing a surface acoustic wave device, comprising: 3. The surface acoustic wave device (30) according to claim 1.
In a package in which the metal patterns (65 to 68) are formed, the ground side terminal portion (42, 4) of the surface acoustic wave element (30).
5) and metal bumps (60-63) are formed on the signal terminal portions (47, 48) formed on the input signal line (43) and the output signal line (46), and the cover plate of the package. (64) or a ground plate having a grounding metal pattern (67, 68) formed in a comb shape, and the metal bumps (62, 63) and the grounding metal pattern (67, 68) are contact-connected. Surface acoustic wave device. 4. The surface acoustic wave device according to claim 1, wherein the first auxiliary terminal portion is provided outside the output signal line (46) so as to face the first ground side terminal portion (42). (9
1) and the first ground side terminal portion (4)
2) and the first auxiliary terminal portion (91) between the first metal film (9)
By 3), the output signal line (46) is straddled and connected in an air bridge shape, and the outside of the input signal line (43) faces the second ground side terminal portion (45). Forming a second auxiliary terminal portion (92) on the second ground terminal portion (45) and the second auxiliary terminal portion (92) by a second metal film (94). A surface acoustic wave device characterized by being connected in an air bridge shape across the signal line (43). 5. The surface acoustic wave device (90) according to claim 4.
In a surface acoustic wave device in which a metal pattern (106 to 109) is housed in a package, the first and second metal films (93, 94) of the surface acoustic wave element (90), and Metal bumps (101 to 104) are formed on the signal terminal portion (47) of the input signal line (43) and the signal terminal portion (48) of the output signal line (46), and the cover plate (105) of the package is formed. Alternatively, the surface acoustic wave device is characterized in that the metal patterns (106 to 109) formed on the bottom plate and the metal bumps (101 to 104) are contact-connected.