JPH07154185A - Surface acoustic wave device and its manufacture - Google Patents

Abstract

PURPOSE:To facilitate the surface mount of a surface acoustic wave device, to simplify a surface acoustic wave element support structure, to simplify the device manufacture process, to attain high performance of the device and high quality, to make the size small and to reduce the cost. CONSTITUTION:A surface acoustic wave element (chip) 11 in which interdigital electrodes (IDT) 12 are formed on a piezoelectric substrate is arranged so that a bottom side of a surface mount package 13 and an IDT forming side are opposite to each other. In this case, a conductive pad 31 having a contract/ expansion nature is interposed and inserted between them to obtain electric continuity. Furthermore, while a pressing force is exerted to the chip with a drawn processing cap 30, the cap is welded to the package to apply air-tight sealing to the package.

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 device,
In particular, the present invention relates to a surface acoustic wave device having an improved support structure of a surface acoustic wave element (hereinafter referred to as a chip) that can be easily mounted on a surface, and a manufacturing method thereof.

[0002]

2. Description of the Related Art As a conventional general surface acoustic wave device, a device having a structure shown in FIG. 6 is known. To briefly explain this, a surface acoustic wave device generally denoted by reference numeral 10 includes a chip 11 as a surface acoustic wave element made of a piezoelectric substrate, and one side surface (upper surface) of the chip 11 has at least one pair or more. Input / output transducer (hereinafter ID
Interdigitated electrode 12 which is an electrode portion formed by (T) is formed.

Reference numeral 13 is a surface-mounting container entirely made of a ceramic material or the like.
When accommodating 1, the chip 11 is accommodated and arranged with the surface on which the interdigitated electrode 12 is formed facing up.

Then, the other side of the chip 11 is die-bonded to the bottom surface of the container 13 via an adhesive 16, and then the input / output pad portion 12a of the IDT and the container 13 are joined.
The metallized pad portion 14a formed on a part of the bottom surface of the above is wire-bonded with the conductive wire 17 so as to be electrically connected to be assembled.

Reference numeral 18 denotes a cap which is welded and connected to the open end of the container 13 with a seam ring 15 interposed therebetween.
It has been general practice to hermetically seal the whole by joining the cap 18 to the container 13.

Further, the surface wave generated by the IDT on the upper surface of the chip 11 is reflected by the end surface in the traveling direction of the surface wave and interferes with each other to deteriorate the filter characteristics. Therefore, as shown in FIG. Conventionally, a method of forming a sound absorbing agent 19 such as silicon at a required position on the end face has also been adopted as needed.

Further, as the surface acoustic wave device as described above, a device having a structure as shown in FIG. 8 has been conventionally known. That is, in the figure, reference numeral 20 is a metal container (stem) for housing the chip 11, 21 is a cap that covers the upper surface of the metal container 20, and the metal container 20 and the cap 21 are resistance-welded. And the like, and are hermetically sealed.

When the chip 11 is fixed to the metal container 20, the surface of the chip 11 on which the interdigitated electrodes 12 are formed faces upward, and the other surface of the chip 11 is fixed to the metal container 20 with the adhesive 16. Then, the input / output pad portion 12a of the IDT and the lead terminal 22 provided on the metal container 20 are wire-bonded with the conductive wire 17 so that electrical conduction can be obtained. Reference numeral 23 is a glass terminal having an insulating property, which is provided by filling a hole portion penetrating and holding the lead terminal 22 of the metal container 20.

Here, in the conventional example shown in FIG. 8, a substantially flat plate-like metal container 20 is used, and a substantially cup-like shape is provided so that the chip 11 and the like can be mounted on the upper surface portion thereof in a mountable state. The case where the cap 21 is used is shown.

[0010]

By the way, in the conventional example as described above, according to the surface acoustic wave device having the former configuration shown in FIGS. 6 and 7, the step of applying and curing the adhesive at the time of die bonding. Since it also includes a wire bonding process and the like, and additionally includes a sound absorbing coating process and a curing process, there is a drawback that not only a great amount of time is required but also the capital investment becomes enormous. .

Further, in the conventional device as described above, there is a problem that the structure of the entire device is complicated and the size of the device is increased due to the assembling posture of the chip 11 and the electrical connection structure with each part. .

Further, in order to surface mount the conventional surface acoustic wave device 10 as described above, since the metallized pad portion 14a is required for the container 13 at the time of wire bonding, the container is formed correspondingly larger. In addition, it is necessary to provide a cavity corresponding to the thickness of the chip 11 in the container 13 in order to ensure workability in a horizontal posture during wire bonding.

In particular, in order to meet such a request,
It is necessary to form the surface-mounting container 13 with the same material such as a ceramic material so as to have a three-layer structure (divided surfaces are indicated by wavy lines in FIGS. 6 and 7), which has a drawback of increasing cost. .

Further, as a surface acoustic wave device of this type, for example, in Japanese Utility Model Laid-Open No. 56-15118, a cap having a conductor pattern formed on an insulating thin plate is mounted and mounted by die-bonding a chip on a container substrate. It is also known that the electrode terminal portion (the input / output pad portion of the IDT) of the chip and the conductor pattern portion are fixed to each other. In this conventional example, the wire bonding process in the conventional example shown in FIGS. 6 and 7 can be omitted.

However, in this conventional example as well, in order to omit the wire bonding step after die bonding, a conductive pattern is formed on the insulating thin plate and directly fixed to the electrode terminals of the chip, which is applicable to the surface mounting type. If you are having problems.

That is, when the surface acoustic wave device of this type is a surface mount type, since the insulating thin plate serving as the lid of the container is made of an insulating material, it is possible to ensure complete airtightness by seam welding or the like. This is not possible, and a separate step such as molding the outer periphery of the joint portion or sealing with a low melting point glass material is required.

When these airtight sealing treatments are carried out,
It is easy to affect the connection reliability between the chip and the conductor pattern, and as a result, surface mounting is difficult. In particular, in the case of the container, the chip, and the insulating thin plate, there is a difference in thermal expansion depending on the material used, and the problem that a stress is added to the chip or the electrically conductive portion with the chip due to the thermal expansion of the container, There are drawbacks such as unstable frequency characteristics.

Further, since the IDT formed on the chip is mounted in the container with the upper surface facing upward, impurities and dust generated in the container are apt to directly adhere to the IDT, resulting in characteristic deviation due to such impurity adhesion. However, there is also a drawback that the electrical characteristics are likely to be deteriorated.

Further, in the above-mentioned conventional example, the latter surface acoustic wave device shown in FIG. 8 also includes a step of applying and curing an adhesive at the time of die bonding and a wire bonding step. In addition, not only is the capital investment enormous, but since the IDT formed on the chip 11 is placed and housed so as to be on the upper surface of the metal container 20, the inside of the container 20 is covered when the cap 21 is covered. There is also a drawback in that impurities generated in step 2 and dust due to plating of the cap 21 and dust scattered along with discharge (spark) generated during resistance welding are likely to be directly attached to the IDT, which may cause deterioration of electrical characteristics. .

Further, also in such a conventional example, since the metal container 20 and the chip 11 are strongly fixed and held by the adhesive 16, the deformation stress when airtightly sealed by resistance welding or the like is directly applied to the chip 11. There is also a defect that the frequency is easy to be propagated and the frequency is easily changed as the deformation stress is changed with the passage of time.

Further, as this type of surface acoustic wave device,
For example, in Japanese Unexamined Patent Publication No. 4-310009, in order to enable signal connection without wire bonding, a signal input / output electrode for capacitively coupling is formed facing an electrode on a circuit board to be mounted. . It is also known to eliminate the wire bonding by devising the piezoelectric substrate such as providing a recess in order to increase the capacitance. However, such a conventional example is effective when directly mounted on a circuit board in a chip state, and is not suitable for a normal independent surface mount component.

Further, Japanese Laid-Open Patent Publication No. 4-170811 discloses a surface acoustic wave device in which a metal bump is formed on a bonding pad portion of a chip and is contact-connected to a metallized pad portion of a container to omit a wire bonding step. Are known. However, also in this conventional example, when the metal bumps formed on the chip and the container are contact-connected, when forming a plurality of bumps, it is necessary to improve the horizontality and the flatness as much as possible, and to make contact with each other. It was difficult.

That is, in this conventional example, if the flatness is poor, a contact point at which electrical continuity cannot be obtained occurs, and a serious characteristic defect is likely to occur. Furthermore, even if the electrical characteristics of a single component are obtained, a slight deformation such as a warpage occurs in the container due to the stress when mounting on a printed circuit board or a ceramic substrate of equipment, etc., and the metal bump and the contact connection point are bad. However, there is a drawback that a characteristic failure due to a poor electrical continuity is likely to occur.

When applying such a conventional example to the one using the metal container 20 as shown in FIG.
There is also a possibility that the reliability of electrical connection may be significantly deteriorated due to the deformation stress at the time of sealing due to resistance welding or the like.

Further, in the above-mentioned conventional example, when the metal bumps are heated and pressed to be connected and fixed to the container, deformation stress when mounting on a printed circuit board or a ceramic substrate and expansion of the container due to thermal stress under environmental conditions, The stress due to contraction
Since it is assumed that the connection and the fixing portion of the metal bumps are also reached, there is a drawback that the connection area and strength of the metal bumps must be sufficiently considered.

In particular, such a problem is that it is almost difficult to apply to the metal container 20 as shown in FIG. 8 in which the cap 21 is joined by resistance welding or the like as described above. It is desired to take some measures capable of solving the above.

The present invention has been made in view of the above circumstances, and facilitates surface mounting, simplifies the surface wave element support structure, simplifies the assembly work process, and hermetically seals. For the purpose of obtaining a surface acoustic wave device and a method for manufacturing the same, which are capable of achieving high reliability, stable reliability of electrical continuity, downsizing of the entire device, and cost reduction. There is.

[0028]

In order to meet such demands, a surface acoustic wave device and a method for manufacturing the same according to the present invention are provided with a surface acoustic wave device having interdigitated electrodes (IDT) formed on a piezoelectric substrate. The (chip) is arranged so that its IDT formation surface faces the bottom surface of the surface-mounting container, and electrically conductive is obtained by sandwiching a conductive pad having an appropriate stretchable shape and structure between them. It was made possible. Here, the same applies to the conductive pad, for example, a rectangular ring-shaped conductive pad having elasticity as a connector in which metal fibers are embedded in only one direction of silicon rubber.

Further, in the surface acoustic wave device and the method for manufacturing the same according to the present invention, the cap that closes the open end of the surface mount container is subjected to an arbitrary drawing process, and the cap is joined to the container to hermetically seal the container. The cap is adapted to hold the chip under pressure while applying a pressing force to the chip. Here, a cushioning material having an arbitrary shape and having elasticity can be interposed between the cap and the tip to control the pressing force applied from the cap. For example, if a rectangular hole is formed along the chip in the center of the sheet, the pressing force can be concentrated on the outer periphery of the chip.

Further, in the surface acoustic wave device and the method for manufacturing the same according to the present invention, the interdigital electrode (ID) is formed on the piezoelectric substrate.
The surface acoustic wave element (chip) formed with
The T-formed surface is arranged so as to face the inner end of the lead terminal that is insulated and held in the metal container, and the electrically conductive pad having elasticity is interposed between these to sandwich the T-shaped surface so that electrical conduction can be achieved. It is configured to be obtained.

Further, in the surface acoustic wave device and the method for manufacturing the same according to the present invention, a cap is covered so as to cover the metal container and hermetically sealed, and a pressing force is applied to the chip by this cap to hold it under pressure. It is configured in. Here, if necessary, a chip positioning guide made of any insulating material is provided between the chip and the bottom surface of the metal container, and a container-side lead terminal is incorporated into this to hold the chip, or a cap is provided. Between the chip and
It is advisable to interpose an arbitrary cushioning material and apply a uniform pressing force to the chip so that pressure retention in the container can be obtained.

[0032]

According to the present invention, a conductive pad is arranged on the bottom surface of a surface-mounting container, and a chip having an IDT formed on a piezoelectric substrate is provided with its IDT forming surface facing the bottom surface of the surface-mounting container. Arrange the pads so that they fit in,
By making it possible to obtain electrical continuity of the chip, and then by joining the open end of the surface mount container with a cap that has been subjected to a drawing process, and by hermetically sealing with the pressing force applied to the chip. Thus, the surface acoustic wave device in which the chip is pressure-held and surface-mounted is obtained.

Further, according to the present invention, the conductive pad is arranged directly or indirectly through the chip positioning guide on the metal container holding the lead terminal in an insulating state, and the conductive pad is formed on the conductive pad. Overlay the pads, and then the chip I
A surface acoustic wave is obtained by stacking the DT forming surface and the inner end of the lead terminal so as to face each other, and then placing a suitable cushioning material on the upper portion of the lead terminal and covering the cap with the metal container and airtightly sealing the metal container by resistance welding or the like. A device is obtained.

[0034]

FIG. 1 shows an embodiment of a surface acoustic wave device and a method of manufacturing the same according to the present invention, in which the same or corresponding parts as those in FIGS. Detailed description thereof will be omitted.

According to the present invention, in the surface acoustic wave device 10 having the above-described structure, the chip 11 in which the interdigital finger-shaped electrodes (IDT) 12 are formed on the piezoelectric substrate is formed by the I
Surface mount container 13 whose DT forming surface is made of a ceramic material or the like
It is characterized in that it is arranged so as to face the bottom surface of the substrate and that electrically conductive pad 31 having elasticity is sandwiched between them so that electrical conduction can be obtained.

Here, the above-mentioned conductive pad 31 is placed on the metallized pad portion 14a of the metallized pattern 14 formed by being exposed on the bottom surface of the container 13, and the metallized pad portion 14a and the IDT on the chip 11 side. Is electrically connected to the input / output pad section 12a.

Further in accordance with the present invention, the surface mount container 1
The cap 30 that closes the open end of 3 is subjected to an arbitrary drawing process, the cap 30 is joined to the container 13 to hermetically seal, and at the same time, the cap 11 is pressed and held while applying a pressing force to the chip 11. It is configured to do.

Here, as shown in the figure, the cap 30 is brought into contact with the side of the chip 11 arranged on the bottom surface of the container 13 via the conductive pad 31 on the side opposite to the IDT forming surface, and the required repulsive force is exerted. Is formed by drawing with a pressing portion for pressing the chip 11 against the bottom surface side of the container 13. Further, the cap 30 is hermetically sealed by welding-connecting it to the edge of the opening end side of the container 13 via the seam ring 15.

According to such a configuration, the surface mount container 1
3, the conductive pad 31 is arranged on the bottom surface of the chip 3, and the chip 11 having the IDT formed on the piezoelectric substrate is arranged so that the IDT forming surface faces the bottom surface of the surface mounting container 13 and the conductive pad 31 is sandwiched. By doing so, electrical continuity of the chip 11 can be obtained.

Further, in the above-mentioned assembled state, the cap 3 on which the opening end of the surface mount container 13 is pre-drawn.
0 is combined, joined by welding connection, and hermetically sealed in a state in which the pressing force is applied to the chip 11, whereby the chip 11 is held under pressure, and the surface acoustic wave device 10 for surface mounting is provided. Obtainable.

According to the above-mentioned structure, the die bonding process for fixing the chip 11 with the adhesive and the chip 1 as in the conventional method, although the structure is simple.
1 does not require a wire bonding step for obtaining electrical continuity between the surface mounting container 13 and the surface mounting container 13 and has an advantage of simplifying the manufacturing process.

Further, when fixing the chip 11 to the container 13, the conventional adhesive fixing is not used, and the conductive pad 31 is held in close contact only by the pressure holding force of the cap 30, so that the container 13 is held. The stress applied to the chip 11 due to the difference in thermal expansion between the two becomes small and the frequency characteristics become stable.

When the surface mount container 13 is made of a ceramic material, a three-layer structure including a bottom surface of the container, a cavity surface for housing the chip, and a surface having a bonding pad for wire bonding with the chip is conventionally required. However, according to the present invention, since wire bonding is unnecessary, a two-layer structure is sufficient, and there are advantages such as the cost of the container 13 becoming low.

Further, since the IDT formed on the chip 11 is arranged so as to face the bottom surface of the container 13, impurities and dust (for example, fine particles of the plating film applied to the cap) generated in the container 13 are directly attached. Adhesion on the IDT can be prevented, characteristic deviation due to adhesion of impurities can be prevented, and deterioration of electrical characteristics can be prevented.

According to the present invention as described above, the surface acoustic wave device 10 of low cost, small size and high performance can be obtained with a simple structure and a simple manufacturing method.

FIGS. 2 and 3 show another embodiment of the surface acoustic wave device and the method for manufacturing the same according to the present invention, which are the same as those shown in FIGS. 1, 6 and 7 described above. Corresponding parts are designated by the same reference numerals, and detailed description will be omitted.

According to this embodiment, in the surface acoustic wave device 10 having the above-mentioned structure, the chip 11 having the interdigitated electrode (IDT) 12 formed on the piezoelectric substrate.
And the bottom surface of the surface-mounting container 13 arranged so that the IDT forming surfaces face each other, the conductive pad 35 in the shape of a rectangular ring having elasticity is sandwiched so that electrical conduction can be obtained. It is characterized by

The above-mentioned rectangular ring-shaped conductive pad 35 is, for example, a connector in which a metal fiber 35a is embedded only in one direction of silicon rubber, and has electrical conduction in only one direction. The rectangular ring-shaped conductive pad 35 is formed on the bottom surface of the container 13 by exposing the metallized pad portion 14 of the metallized pattern 14.
The metallized pad portion 14a placed on a and the input / output pad portion 12a of the IDT on the chip 11 side are electrically connected to each other through the embedded metal fiber 35a.

Further, according to this embodiment, the cap 30 made of a metal material or the like that has been subjected to an arbitrary drawing process for closing the open end of the surface mounting container 13 made of a ceramic material or the like is provided.
When the chip 11 is joined to the container 13 to be hermetically sealed and the chip 11 is pressed and held under a pressing force applied thereto, the cap 30 and the chip 11 have elasticity of any shape. The sheet-like cushioning material 36 is interposed so that the pressing force applied from the cap 30 is controlled. Here, the sheet-shaped cushioning material 36 in this embodiment is used.
Has a hole in the center so that the pressing force is concentrated on the outer peripheral portion of the chip 11.

Although FIG. 3 is a schematic perspective view showing a disassembled main structure of the constituent parts in this embodiment, the IDT, the seam ring 15 and the like are omitted for simplification.

According to such a configuration, the surface mount container 1
The rectangular ring-shaped conductive pad 35 is arranged on the bottom surface of the chip 3, and the chip 11 having the IDT formed on the piezoelectric substrate is
The T-shaped surface faces the bottom surface of the surface-mounting container 13, the conductive pad 35 is arranged so as to be sandwiched, and the metal fiber 3 embedded only in one direction of the conductive pad 35.
Electrical conduction can be obtained through 5a.

Further, in the above-mentioned assembled state, the cap 30 in which the open end of the surface mount container 13 is pre-drawn is drawn.
The chips 11 are joined together by welding connection, and the pressing force is applied to the chips 11 through the sheet-shaped cushioning material 36 having an elastic property of any shape to hermetically seal the chips, thereby holding the chips 11 under pressure. As a result, the surface acoustic wave device 10 that is surface-mounted can be obtained.

With this structure, as in the above-described embodiment, the die for fixing the chip 11 with the adhesive as in the conventional case has a simple structure and a simple manufacturing method. A bonding process and a wire bonding process for obtaining electrical continuity between the chip 11 and the surface mount container 13 are unnecessary. Further, in order to prevent the surface wave excited by the IDT from reflecting and interfering with the end surface of the chip 11 in the traveling direction of the surface wave, the sound absorbing agent 19 (see FIG. 7) which has been conventionally applied is replaced with a rectangular ring-shaped conductive material. Since a part of the property pad 35 and the end surface of the chip 11 are pressed against each other to prevent reflection, it is not necessary. Therefore, the conventional sound absorbing agent application step can be omitted, and the manufacturing process can be simplified.

Furthermore, when fixing the chip 11 to the container 13, the rectangular ring-shaped conductive pad 35 is held in close contact with only the pressure holding force of the cap 30 without using the conventional adhesive fixing. The stress applied to the chip 11 due to the difference in thermal expansion from the container 13 is small, and the frequency characteristics are stable.

In addition, the three-phase structure conventionally required when the surface mount container 13 is made of a ceramic material has the two layers of the bottom surface of the container 13 and the cavity surface for accommodating the chip 11 in order to eliminate the need for wire bonding. The structure, or not shown, has the advantage that the seam ring 15 also serves as a cavity for accommodating the chip 11, whereby the structure can be further simplified, the container 13 can be simplified, and the cost can be significantly reduced. Play.

Further, since the IDT formed on the chip 11 is arranged so as to face the bottom surface of the container 13, impurities and dust (for example, fine particles of the plating film applied to the cap) generated in the container 13 are directly exposed. Adhesion on the IDT can be prevented, characteristic deviation due to adhesion of impurities can be prevented, and deterioration of electrical characteristics can also be prevented. Also, with such a structure of the embodiment, the surface acoustic wave device 10 which is inexpensive, small in size and high in performance can be obtained.

In the embodiment shown in FIGS. 2 and 3, the cap 30 need not necessarily be drawn. For example, only by the elasticity of the sheet-shaped cushioning material 36, the pressing force of the cap 30 can be applied
1 may be applied to the surface mount container 13 and the surface mount container 13 may be held under pressure.

FIG. 4 shows another embodiment of the surface acoustic wave device and the method for manufacturing the same according to the present invention, which is the same as or corresponds to FIG. 8 and FIGS. 1 to 3, 6 and 7 described above. The same reference numerals are given to the portions to be described, and detailed description will be omitted.

Now, in this embodiment, the surface acoustic wave device 1 comprising the metal container 20 and the cap 21 as described above.
Chip 1 with IDT formed on piezoelectric substrate at 0
1 is arranged such that its IDT forming surface faces the inner end of the lead terminal 22 held in a metal container 20 made of a metal plate or the like while maintaining insulation, and the stretchable conductive material is provided therebetween. The pad (for example, the rectangular ring shape shown in FIGS. 2 and 3) 35 is sandwiched so that electrical conduction can be obtained.

Here, the conductive pad 35 in this embodiment is used.
Is, for example, in one direction of the silicon rubber, the metal fibers 35
It is a connector in which a is embedded and has electrical conduction only in one direction, and the inner end of the lead terminal 22 provided in the metal container 20 and the input / output pad portion 12 of the IDT.
It is configured to be electrically connected to a through the metal fiber 35a. Further, a hole is formed in the portion of the conductive pad 35 where the IDT overlaps, which is the same as the above-described embodiment.

Further, in this embodiment, a cushioning material 36 having an arbitrary shape is interposed between the chip 21 and the cap 21 which is put on the metal container 20, whereby the chip 1 is formed.
It is configured so that a uniform pressing force can be applied to 1 to hold it under pressure in the container 20.

In this structure, the metal container 2
No. 0 lead terminal 22 and I formed on the piezoelectric substrate.
Electrical connection with the input / output pad portion 12a of the DT can be obtained only in one direction through the metal fiber 35a of the conductive pad 35 having, for example, a rectangular ring shape.

Reference numeral 40 in the figure denotes a chip positioning guide formed between the chip 11 and the bottom surface of the metal container 20 in a substantially concave shape by an arbitrary insulating material such as a ceramic material. The lead terminal 22 on the side of the metal container 20 is further penetrated and incorporated in the guide 40, and the chip 11 is held on the guide terminal 40 via the conductive pad 35 in a state where the inner end is exposed. Good.

The use of such a chip positioning guide 40 has the advantage that a surface acoustic wave device 10 capable of exhibiting various effects can be manufactured in a required state by an extremely simple manufacturing operation.

Further, FIG. 5 shows an embodiment in which the guide 40 for positioning the above-mentioned chip is omitted, but the details thereof are as described above, and a detailed description thereof will be omitted. Of course,
It is needless to say that even with such a configuration, substantially the same operational effects as described above can be obtained.

It is needless to say that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part of the surface acoustic wave device 10 can be appropriately modified or changed. For example, as the aperture shape of the open end of the surface mount container 13 or the caps 30 and 21 joined to the metal container 20, a shape having a pressing portion that can apply a uniform pressing force to the anti-IDT forming surface of the chip 11. However, various modifications are conceivable without being limited to the shapes shown in FIGS. 1, 2, 3 and FIGS. 4 and 5.

Further, in FIG. 2 described above, the cavity is formed on the container 13 side to accommodate the chip 11. However, the surface mounting container 13 side is a single plate, and the cap 30 is formed in a downward concave shape, and the chip 11 is formed. It is also possible to adopt a configuration in which, for example, a glass seal or a solder seal is hermetically sealed while pressurizing.

Further, the rectangular ring-shaped conductive pad 35 in FIGS. 2 and 3 described above can also be arbitrarily deformed to a portion facing the IDT in accordance with the position where the electric signal is derived. Further, a sheet-shaped cushioning material 36 having elasticity that is provided between the chip 11 and the cap 30.
Is optional.

[0069]

As described above, according to the surface acoustic wave device of the present invention, the interdigital electrode (ID) is formed on the piezoelectric substrate.
T), which is a surface acoustic wave element, is
A conductive pad that is arranged so that the DT forming surface faces the bottom surface of the surface-mounting container and has elasticity between them;
Alternatively, since electrical conduction is obtained by sandwiching a stretchable rectangular ring-shaped conductive pad, various excellent effects listed below can be obtained despite the simple structure.

That is, according to the present invention, the die bonding step for fixing the chip with an adhesive and the wire bonding step for obtaining electrical continuity between the chip and the surface mounting container, which are required in the prior art, are not required. , The manufacturing process is greatly shortened, and the equipment is greatly simplified.

Furthermore, according to the present invention, a cap that is subjected to an arbitrary drawing process and closes the open end of the surface mount container is provided.
The cap is bonded to the container to hermetically seal it, and at the same time, the cap is pressed and held while applying a pressing force to the chip to fix the chip in the container without using conventional adhesive fixing. In addition, since the conductive pad can be held in close contact only by the pressure holding force of the cap, the stress for this close contact is reduced, the stress applied to the chip due to the difference in thermal expansion from the container is small, and reliability is improved. In addition, the frequency characteristic becomes stable.

Further, according to the present invention, when the surface mount container is formed of, for example, a ceramic material or the like, the bottom surface of the container which has been generally adopted conventionally, the cavity surface for accommodating the chip, and the chip and wire bonding are performed. In contrast to the three-layer structure with the surface having the bonding pad, the wire bonding is not necessary, so a two-layer structure or even a single-layer structure may be used, the container is inexpensive, and the container is small and thin. There is an advantage that it can be realized.

Furthermore, according to the present invention, since the IDT formed on the chip is arranged so as to face the bottom surface of the container, impurities and dust generated in the container (for example, minute particles of the plating film applied to the cap). ) Can be prevented from directly adhering to the IDT, deterioration of electrical characteristics can be prevented, and reliability is significantly improved.

Further, in the conventional surface acoustic wave device,
The surface wave generated by the IDT is reflected and interferes at the end surface in the traveling direction of the surface wave, and in order to prevent the filter performance from deteriorating, a sound absorbing material such as silicon has conventionally been applied and cured.
According to the present invention, the rectangular ring-shaped conductive pad interposed between the chip and the bottom surface of the container can also serve as the pad, and the manufacturing process can be significantly shortened, for example, the step of applying the sound absorbing material is unnecessary. There is also an advantage.

Further, according to the present invention, the rectangular ring-shaped conductive pad having elasticity is used even if a slight deformation stress generated when the device is mounted on the printed circuit board or the ceramic substrate is applied. Not only can stress be prevented from being directly applied to the chip, but high performance such as stable electrical conduction can be achieved.

Further, according to the surface acoustic wave device of the present invention, the surface acoustic wave element (chip) in which the interdigital electrode (IDT) is formed on the piezoelectric substrate is insulated from the metal container at the surface where the IDT is formed. The lead terminals to be held are arranged so as to face the inner ends of the lead terminals, and a conductive pad having elasticity is interposed between the lead terminals to sandwich the lead terminals so that electrical conduction can be obtained. Since the cap is covered and airtightly sealed to apply a pressing force to the chip to hold the chip under pressure, the same operational effect as described above, such as wire Effects such as omission of a bonding step, omission of an adhesive agent for fixing a chip, reduction of stress for maintaining close contact, and improvement of frequency stability can be achieved.

In particular, according to the present invention, since the IDT formed on the chip is arranged to face the lead terminal side provided in the container, impurities and dust (for example, the plating film applied to the cap) generated in the container are arranged. Particles), and electric discharge (sparks) generated during airtight sealing by resistance welding, etc.
The scattered dust can be prevented from directly adhering to the IDT, the deterioration of the electrical characteristics can be prevented, and the surface acoustic wave device with greatly improved reliability can be obtained.

According to the present invention as described above, the device is small and thin, and the cost is low, the quality is high, and the manufacturing lead time can be shortened by simplifying the manufacturing process. Moreover, a high-performance surface acoustic wave device can be obtained.

Further, according to the method of manufacturing a surface acoustic wave device of the present invention, a surface acoustic wave element in which a conductive pad is arranged on the bottom surface of a surface mounting container and an electrode portion is formed on a piezoelectric substrate, The surface of the surface mount container is made to face the electrode part forming surface, and the conductive pad is sandwiched so that the surface acoustic wave element can be electrically connected to the device in a desired state. Can be manufactured in.

Further, according to the present invention, the cap that closes the open end of the surface mount container is subjected to a required drawing process, and this cap is combined and joined to the open end of the surface mount container, and the pressing force is applied to the chip. The surface acoustic wave device having the above-mentioned various effects can be manufactured in a required state by an extremely simple manufacturing operation by airtightly sealing the container so as to obtain a pressure holding state in the container. There is an advantage.

Further, according to the method of manufacturing the surface acoustic wave device of the present invention, the guide for positioning the chip is selectively installed in the metal container, and the conductive sheet is further laid on the guide so that the IDT forming surface of the chip is formed. , The lead terminals that are penetrated and held by the metal container and the chip positioning guide are placed facing each other on the inner end, and a suitable cushioning material is placed on top of them and covered with a cap, and the container is hermetically sealed by resistance welding or the like. By stopping the operation, there is an advantage that the surface acoustic wave device having various effects described above can be manufactured in a required state by a very simple manufacturing operation.

Further, according to the present invention, the deformation stress at the time of sealing and the deformation stress at the time of thermal expansion can be absorbed by the elastic cushioning material and the electrically conductive pad having elasticity, so that the chip is uniformly distributed. It is possible to obtain an appropriate pressure-holding state of the chip in the container by applying a sufficient pressing force, and it is possible to obtain an extremely highly stable surface acoustic wave device.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a main part showing an embodiment of a surface acoustic wave device and a method for manufacturing the same according to the present invention.

FIG. 2 is a schematic cross-sectional view of a main part showing another embodiment of the surface acoustic wave device and the method for manufacturing the same according to the present invention.

FIG. 3 is a schematic exploded perspective view showing a main configuration of the apparatus shown in FIG.

FIG. 4 is a schematic cross-sectional view of a main part showing another embodiment of the surface acoustic wave device and the method for manufacturing the same according to the present invention.

5 is a schematic cross-sectional view of a main part showing a modification of the surface acoustic wave device and the manufacturing method thereof shown in FIG.

FIG. 6 is a schematic sectional view showing a conventional surface acoustic wave device.

FIG. 7 is a schematic sectional view showing another example of a conventional surface acoustic wave device.

FIG. 8 is a schematic sectional view showing another example of a conventional surface acoustic wave device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Surface acoustic wave device, 11 ... Surface acoustic wave element (chip), 12 ... Interdigitated electrode (IDT; electrode part), 12a
Input / output pad portion, 13 ... Surface mount container, 14 ... Metallized pattern, 14a ... Metallized pad portion, 15 ... Seam ring, 19 ... Sound absorbing material, 20 ... Metal container, 21 ... Cap, 22 ... Lead terminal, 23 ... Glass Terminal, 30 ...
Cap, 31 ... Conductive pad, 35 ... Rectangular ring-shaped conductive pad, 35a ... Metal fiber, 36 ... Stretchable sheet-shaped cushioning material, 40 ... Chip positioning guide.

Claims (13)

[Claims] 1. A surface acoustic wave device in which a surface mounting container accommodates a surface acoustic wave element in which at least a pair of input / output transducer electrodes are formed on a piezoelectric substrate. The electrode formation surface and the bottom surface of the surface-mounting container are arranged so as to face each other, and a conductive pad having elasticity is interposed between them so that they can be electrically connected. A surface acoustic wave device. 2. The surface acoustic wave device according to claim 1, wherein the conductive pad interposed between the electrode portion forming surface of the surface acoustic wave element and the bottom surface of the surface mounting container is a rectangular ring shape. And a rectangular ring-shaped portion of the conductive pad is arranged along the peripheral edge of the surface acoustic wave element. 3. The surface acoustic wave device according to claim 1, wherein the cap that closes the open end of the surface mount container is formed by drawing, and the cap is joined to the open end of the container. A surface acoustic wave device characterized in that it is hermetically sealed, and that the cap applies a pressing force to the surface acoustic wave element to hold it under pressure. 4. A surface acoustic wave device in which a surface acoustic wave element formed by forming at least a pair of input / output transducer electrode portions on a piezoelectric substrate is housed in a metal container. By arranging the part forming surface and the inner end of the lead terminal, which is insulated and held in the metal container, to face each other, and sandwiching a conductive pad having elasticity between them, A surface acoustic wave device, characterized in that the surface acoustic wave element and the lead terminal are electrically connected to each other. 5. The surface acoustic wave device according to claim 4, wherein the conductive pad interposed between the electrode portion forming surface of the surface acoustic wave element and the bottom surface of the surface mounting container is a rectangular ring shape. A surface acoustic wave device characterized by using a device having: 6. The surface acoustic wave device according to claim 4 or 5, wherein a cap is provided to cover the metal container to hermetically seal the surface of the metal container, and a pressing force is applied to the surface acoustic wave element by the cap. A surface acoustic wave device characterized by being configured to hold pressure. 7. The surface acoustic wave device according to claim 5, 6, or 7, wherein a surface acoustic wave element positioning guide made of an insulating material is provided between the surface acoustic wave element and the bottom surface of the metal container. A surface acoustic wave device characterized by being provided so as to be interposed. 8. The surface acoustic wave device according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6 or claim 7, wherein the cap and the surface acoustic wave element are disposed between the cap and the surface acoustic wave element. A surface acoustic wave device, characterized in that a compressive force having elasticity is interposed so that a pressing force is applied to the surface acoustic wave element to hold it under pressure. 9. A method of manufacturing a surface acoustic wave device, comprising a surface mounting container in which a surface acoustic wave element having at least a pair of input / output transducer electrodes formed on a piezoelectric substrate is housed. Place a conductive pad on the bottom surface of the device, and place a surface acoustic wave element with an electrode part formed on the piezoelectric substrate so that the surface where the electrode part is formed faces the bottom surface of the surface-mounting container. A method for manufacturing a surface acoustic wave device, characterized in that the electric conduction of the surface acoustic wave element is obtained by disposing the surface acoustic wave element so as to be embedded. 10. The method of manufacturing a surface acoustic wave device according to claim 9, wherein a cap that closes the open end of the surface mount container is subjected to a drawing process, and the cap is combined with and joined to the open end of the surface mount container. A method for manufacturing a surface acoustic wave device, characterized in that a pressing force by the cap is applied to a surface acoustic wave element so that a pressurized and held state in a container is obtained, and the surface acoustic wave device is hermetically sealed. 11. The method of manufacturing a surface acoustic wave device according to claim 9 or 10, wherein a cap that closes an open end of the surface mount container is subjected to a drawing process, and the cap is assembled to the open end of the surface mount container. They are joined together and a stretchable cushioning material is interposed between this cap and the surface acoustic wave element, and the pressing force of this cap is applied to the surface acoustic wave element to obtain a pressure holding state in the container. A method of manufacturing a surface acoustic wave device, the method including airtightly sealing as described above. 12. A method of manufacturing a surface acoustic wave device comprising a surface of a piezoelectric substrate, the surface acoustic wave device comprising electrodes formed by at least one pair of input / output transducers, and a metal container. , A surface acoustic wave element positioning guide made of an insulating material is placed in the lead terminal on the metal container side, and an elastic conductive pad is placed on the surface acoustic wave element positioning guide. The surface of the surface acoustic wave element on which the electrodes are formed faces each other, and electrical conduction between the inner end of the lead terminal and the electrode portion of the surface acoustic wave element is obtained through the conductive pad. Method of manufacturing surface acoustic wave device. 13. The method of manufacturing a surface acoustic wave device according to claim 12, wherein when a metal container provided with the surface acoustic wave element is covered with a cap and hermetically sealed, a buffer is provided between the cap and the surface acoustic wave element. A surface acoustic wave, characterized in that a pressing force is applied to the surface acoustic wave element through a material so that the metal container and the cap are hermetically sealed so as to obtain a pressure holding state in the metal container. Device manufacturing method.