JP3437836B2 - Surface acoustic wave device and method of manufacturing surface acoustic wave device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to resin sealing of electronic components such as surface acoustic wave devices, and more particularly to a method of resin sealing electronic components connected by a flip chip bonding method.

[0002]

2. Description of the Related Art In recent years, many surface acoustic wave devices have been used as elements such as filters, delay lines, and oscillators of electronic devices that use radio waves. Electronic devices used in fields such as mobile communication are required to have reduced size and high reliability, and due to this reduction, miniaturization of surface acoustic wave devices is also required.

In the surface acoustic wave element, for example, an electric signal is applied to an input interdigital transducer of a comb-teeth type electrode portion formed on a piezoelectric substrate, which is converted into a surface acoustic wave and transmitted on the piezoelectric substrate. Further, the surface acoustic wave reaching the output interdigital transducer of the other comb-teeth type electrode portion is converted into a side electric signal and taken out to the outside.

An example of the prior art of the surface acoustic wave device in which this surface acoustic wave element is sealed is shown in FIGS. The conventional surface acoustic wave device is sealed by a base substrate 10 and a cap 11, as shown in FIG. FIG. 4B is a perspective view of the cap 11, showing that the surface acoustic wave device 1 is disposed inside the base substrate 10 and the bumps 5 are used to form the device 1.
And the base substrate 10 are connected. FIG. 5 shows FIG.
It is sectional drawing of the EE direction of (b). The comb-shaped electrode part
It is arranged on the back surface of the element 1 facing the base substrate 10. From this arrangement, face down bonding (FD
B) called structure.

The conventional surface acoustic wave device having the FDB structure is inexpensive and suitable for mass production, but the height is increased due to the use of the cap 11, and the cap 11 is adhered to the base substrate 10. There is a problem that the bottom surface of the base substrate 10 becomes large in order to secure the adhesive surface.

[0006]

Therefore, an element 1 as shown in FIG. 6 (a) is provided with a base substrate 4 and a polymer material 3.
It was improved by sealing with. In this improvement, the height of the surface acoustic wave device can be reduced and the bottom area of the base substrate 4 can be reduced by not using the cap 11.

However, FIG. 6B shows the line segment FF of FIG.
Although it is an enlarged view of a region on the left side, it was found that the comb-shaped electrode 7 through which the elastic wave propagates also comes into contact with the polymer-based material 3 as the sealing resin, so that the electrical characteristics are deteriorated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface acoustic wave device which can be miniaturized without causing deterioration of electrical characteristics.

Another object of the present invention is to provide a method of manufacturing a surface acoustic wave device which can be miniaturized without causing deterioration of electrical characteristics.

[0010]

In order to achieve the above object, a first feature of the present invention is that a base substrate having a plurality of extraction electrodes arranged on the surface thereof is disposed so as to be opposed to and spaced from the base substrate. , A piezoelectric substrate having a comb-teeth type electrode and an electrode pad connected to the comb-teeth type electrode formed on a main surface facing the base substrate, a bump connecting the electrode pad to the lead-out electrode, and a piezoelectric substrate sealed. The surface acoustic wave device is provided with a sealing material for stopping, and the sealing material is separated from the comb-teeth-shaped electrode surface of the piezoelectric substrate by an oil agent.

The first feature of the present invention is even more effective when the sealing material is made of a resin material such as a thermosetting resin or an epoxy resin and the oil agent is an insulating oil agent.

A second feature of the present invention is to form a surface acoustic wave element by forming comb-teeth type electrodes and electrode pads on one main surface of the piezoelectric substrate, and to apply an oil agent to the surface of the surface acoustic wave element on which the electrode is formed. A step of applying a base substrate having a lead electrode and a surface acoustic wave element facing each other, bump-connecting the electrode pad and the lead electrode, and a step of sealing the surface acoustic wave element with a resin material, And a step of releasing the resin material from the electrode forming surface of the surface acoustic wave element at the same time. The method of manufacturing a surface acoustic wave device, comprising:

That is, the sealing material is released from the electrode forming surface of the surface acoustic wave element by the oil agent, and the hollow is secured on the electrode forming surface, so that the characteristics of the filter are not impaired.
Then, the package size can be reduced similarly to FIG.

The sealing resin plays a role of protecting the surface acoustic wave element having the input and output comb-teeth type electrodes from external force, liquid such as moisture and water, and its material is a polymer material. , Epoxy resin and the like can be used.

As the base substrate, an insulating substrate such as ceramic, plastic, polyimide substrate or glass can be used.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, two embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. It should be noted that the drawings are schematic, and the relationship between the thickness and the plane dimension, the aspect ratio of the plane dimension, and the like are different from the actual ones.

Example 1 FIG. 1A is a perspective view of a surface acoustic wave device according to Example 1 of the present invention. FIG. 1B is a sectional view taken along line AA of FIG. FIG. 1C is an enlarged view of the left half of the line segment BB of FIG. The surface acoustic wave device according to the first embodiment of the present invention includes a base substrate 4 having a plurality of extraction electrodes 9 arranged on the surface thereof, and conductive bumps 5 arranged on the extraction electrodes 9.
Piezoelectric substrate and comb-shaped electrode 7 arranged on the back surface of the piezoelectric substrate
And a surface acoustic wave element 1 having an electrode pad 8 disposed on the back surface of the piezoelectric substrate and electrically connected to the comb-teeth-shaped electrode 7 and having a back surface in contact with the bumps 5, and a surface acoustic wave element 1 provided on the base substrate 4 and surrounding the surface acoustic wave element 1. -Based material 3 that is arranged as a sealant
And a thin oil agent 2 which is disposed on the surface of the polymer material 3 facing the surface acoustic wave element 1 and has a hollow portion 6 between the comb electrode 7 and the thin material.

Since the hollow portion 6 is formed and the comb-teeth-shaped electrode 7 is no longer in contact with the polymer material 3, the electrical characteristics are not deteriorated.

At least 1 is provided between the polymer material 3 serving as the sealing resin and the comb-teeth type electrode 7 of the surface acoustic wave element 1.
It is preferable that the hollow portion 6 has a height of about μm or more.
This is because the surface acoustic wave may reach submicron amplitude.

Next, a method of manufacturing the surface acoustic wave device according to the first embodiment of the present invention will be described.

First, as shown in FIG. 2A, a base substrate 4 having a plurality of lead electrodes 9 serving as terminals is prepared, and gold bumps 5 are connected to the electrodes 9 using a bump bonding apparatus.

On the other hand, as shown in FIG. 2B, the surface acoustic wave element 1 is formed. On the back surface of the piezoelectric substrate, a pattern of the comb-teeth type electrode 7 and the electrode pad 8 made of an aluminum film is formed.
Divide into chips by using a dicing device.

Next, as shown in FIG. 2C, a thin oil agent 2 for releasing is formed on the surface of the surface acoustic wave element 1.

For the thin insulating coating layer 2, for example, CRC rust preventive agent, mold release agent, cutting oil, silicon grease, pumping grease, molybdenum grease, moly coat HP.
Grease (manufactured by Dow Corning Co., Ltd.), Fluorine grease (manufactured by Nichias Co., Ltd.) and the like are available.

Then, as shown in FIG. 2D, the metal pads 8 and the bumps 5 are connected using a flip chip bonder device. By this connection, the element 1 is fixed to the substrate 4, and a face down bonding (FDB) structure is obtained. Also, at the time of this connection, the pad 8 and the bump 5
The oil agent 2 located on the contact surface of is removed. This can be confirmed by the fact that good conduction is obtained. It is conceivable that the oil agent 2 was destroyed by the application of heat or ultrasonic waves when connecting.

Further, as shown in FIG. 2D, the surface acoustic wave element 1 is packaged by using the polymer material 3.
The polymer material 3 and the chip (element) 1 are bonded to each other via the thin insulating coating layer 2.

The polymer material 3 is, for example, a polyimide resin or a PP / EPR polymer alloy (PP / Ethy).
len ・ Propyrene Rubber Ble
nd), TEX (manufactured by Tonen Chemical Co., Ltd., polyolefin-based TPE (Polyolefin Thermopl).
astic Elastomer), Toughprene (manufactured by Asahi Kasei Corporation, SBS (Styrene-Butdi)
ene-Styrene Block Copolym
er)), Maxloy A (manufactured by Japan Synthetic Rubber Co., Ltd., P
A-ABS (PA-Acrylonitrile-Bu
tadiene-Styrene Copolyme
r)), X-9 (manufactured by Unitika Ltd., PA / PAR)
(PA / Polyarylate), Tenac (Asahi Kasei Corp., POM / TPU (POM / Thermo)
plastic Polyurethane)).

Finally, as shown in FIG. 1C, heat is applied to cure and shrink the polymer material 3. The oil agent 2 is peeled off from the interface with the surface acoustic wave element 1. A hollow portion 6 is formed between the polymer material 3 which is a sealing resin and the comb-teeth type electrode 7 of the surface acoustic wave element 1. The oil agent 2 is peeled off from the interface with the element 1 because the adhesive force with the element 1 is very small. As a result, the comb-teeth-shaped electrode 7, which is the active surface of the element 1, does not come into contact with the polymer material 3,
Does not hinder the operation of the surface acoustic wave device.

The surface acoustic wave device produced in this way is
The size can be reduced both horizontally and vertically. Then, by reducing the package size, high integration can be achieved at the time of mounting.

(Second Embodiment) FIG. 3A is a perspective view of a surface acoustic wave device according to a second embodiment of the present invention. FIG. 3B is a sectional view taken along line CC of FIG. FIG. 3C is an enlarged view of the left half of the line segment D-D in FIG. The surface acoustic wave device according to the second embodiment of the present invention is different from the surface acoustic wave device according to the first embodiment in the arrangement positions of the oil agent 2 and the hollow portion 6. That is, the oil agent 2 that is thinly released is disposed on the surface of the surface acoustic wave element 1 facing the polymer material 3, and has a hollow portion 6 between the surface and the polymer material 3.

Since the hollow portion 6 is formed and the surface acoustic wave generated in the comb-teeth type electrode 7 does not propagate to the polymer material 3, the electric characteristics of the surface acoustic wave device are not deteriorated. The electrical properties are not deteriorated even by the oil agent 2 formed around the comb-teeth-shaped electrode 7 because the oil agent 2 is thin. It is preferable that the film thickness of the oil agent 2 is as thin as possible,
It is preferably 10 molecular layers or less, that is, 0.01 nm or less.

Next, a method of manufacturing the surface acoustic wave device according to the second embodiment of the present invention will be described. The method of manufacturing the surface acoustic wave device according to the second embodiment includes the method of manufacturing the surface acoustic wave device according to the first embodiment and the step of packaging the element 1 shown in FIG. It is the same. The different step is a step of curing and shrinking the polymer material 3 by applying heat.

As shown in FIG. 3C, the polymeric material 3
The oil agent 2 is peeled from the interface with the polymer material 3 when the resin is cured and shrunk. A hollow portion 6 is formed between the polymer material 3 which is a sealing resin and the comb-teeth type electrode 7 of the surface acoustic wave element 1. The oil agent 2 is peeled from the interface with the polymer material 3 because the adhesive force with the polymer material 3 is very small. As a result, the comb-teeth-shaped electrode 7, which is the active surface of the element 1, does not come into contact with the polymer material 3, so that the operation of the surface acoustic wave device is not hindered.

The surface acoustic wave device thus produced is
The size can be reduced both horizontally and vertically. Then, by reducing the package size, high integration can be achieved at the time of mounting.

(Other Embodiments) As described above, the present invention has been described by the two embodiments, but it should be understood that the description and drawings which form a part of this disclosure limit the present invention. Absent. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

For example, in the two embodiments of the present invention, after the polymer material 3 is cured and shrunk, the oil agent 2 is peeled from either the element 1 or the polymer material 3, but adheres to both sides. The hollow portion 6 may be formed inside the membrane 2 as it is. In order to form the hollow portion 6, the polymer material 3
It is sufficient that the intermolecular force of the molecules constituting the oil agent 2 is weakened and the molecules are separated from each other during the curing shrinkage. Therefore, as the oil agent 2, a material which is softened at a temperature at which the polymer material 3 is cured and contracted may be selected.

Although the surface acoustic wave device has been described as an example of the electronic component, the present invention can be similarly applied to other electronic components that require a hollow portion between the element and the sealing resin. I can.

As described above, the technical scope of the present invention is defined only by the matters specifying the invention according to the scope of claims reasonable from the above description.

[0039]

As described above, according to the present invention,
It is possible to provide a surface acoustic wave device that can be miniaturized without causing deterioration of electrical characteristics.

Further, according to the present invention, it is possible to provide a method of manufacturing a surface acoustic wave device which can be miniaturized without causing deterioration of electric characteristics.

[Brief description of drawings]

FIG. 1 is a perspective view and a sectional view of a surface acoustic wave device according to a first embodiment of the present invention.

FIG. 2 is a drawing for explaining the manufacturing method for the surface acoustic wave device according to the first embodiment of the present invention.

FIG. 3 is a perspective view and a sectional view of a surface acoustic wave device according to a second embodiment of the invention.

FIG. 4 is an external view and a perspective view of a conventional surface acoustic wave device.

FIG. 5 is a cross-sectional view of a conventional surface acoustic wave device.

FIG. 6 is a sectional view of an improved surface acoustic wave device.

[Explanation of symbols]

1 Surface acoustic wave element 2 Thin release agent layer 3 Polymer materials 4 base board 5 bumps 6 hollow part 7 Comb-shaped electrode 8 Aluminum pad 9 Extraction electrode 10 Conventional base substrate 11 cap

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Claims (6)

(57) [Claims] 1. A base substrate having a plurality of lead-out electrodes arranged on a surface thereof, and a comb-teeth-shaped electrode and a comb-teeth-shaped electrode which are arranged so as to be opposed to the base substrate with a space therebetween, and are arranged on a main surface facing the base substrate. A piezoelectric substrate on which an electrode pad connected to is formed, a bump connecting the electrode pad to the extraction electrode, and a sealing material for sealing the piezoelectric substrate, wherein the sealing material is an oil agent for the piezoelectric material. A surface acoustic wave device characterized in that the surface acoustic wave device is separated from the comb-teeth-shaped electrode surface of the substrate. 2. The surface acoustic wave device according to claim 1, wherein the sealing material is made of a resin material. 3. The surface acoustic wave device according to claim 1, wherein the sealing material is made of a thermosetting resin. 4. The surface acoustic wave device according to claim 1, wherein the sealing material is made of epoxy resin. 5. The surface acoustic wave device according to claim 1, wherein the oil agent is an insulating oil agent. 6. A step of forming a comb-teeth type electrode and an electrode pad on one main surface of a piezoelectric substrate to manufacture a surface acoustic wave element, a step of applying an oil agent to an electrode forming surface of the surface acoustic wave element, and a step of drawing out. A base substrate having an electrode and the surface acoustic wave element are arranged to face each other, and the pads are connected to the lead electrodes by bumps, the surface acoustic wave element is sealed with a resin material, and the resin material is cured. And simultaneously releasing the resin material from the electrode forming surface of the surface acoustic wave element.