KR101392748B1 - Surface acoustic wave device and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a surface acoustic wave element of high reliability and a method of manufacturing the same which can be stood in consolidated situation than an existing reliability level by adding a material which stands to high humidity to the outer side covered by a resin film when a surface acoustic wave element having a hollowed structure is manufactured. The surface acoustic wave element according to the present invention forms an inter-digitated transducer (IDT) vibration unit to produce surface acoustic wave on a substrate of a piezoelectric element and separately forms a pad from the IDT vibration unit at regular intervals and forms a bump on the pad with a fixed height. The surface acoustic wave element mounts a ceramic substrate on the piezoelectric element with the flip chip bonding through the bump to be faced with a surface in which an IDT electrode unit is formed. A resin film is sealed on the piezoelectric element from the ceramic substrate. Parylene or super hydrophobic coating material is coated on the entire resin film and the ceramic substrate.

Description

TECHNICAL FIELD [0001] The present invention relates to a surface acoustic wave device and a method of manufacturing the surface acoustic wave device.

The present invention relates to a surface acoustic wave device and a method of manufacturing the surface acoustic wave device, and more particularly, to a surface acoustic wave device having a hollow structure by adding a substance resistant to high humidity to a surface covered with a resin film, And a method of manufacturing the surface acoustic wave device.

In general, a surface acoustic wave device is a device that passes a desired frequency and removes an unnecessary frequency.

The surface acoustic wave element includes an input electrode and an output electrode formed on the substrate. When an electric signal is applied to the input electrode of the surface acoustic wave filter, a surface acoustic wave is generated on the surface of the substrate. The surface acoustic wave is transmitted to the output electrode, Is interrupted on the way.

1 is a cross-sectional view of a surface acoustic wave device as a conventional piezoelectric component.

The conventional surface acoustic wave device shown in Fig. 1 has a structure in which a surface acoustic wave element (piezoelectric element) 2 is mounted on a mounting substrate 1 by flip chip bonding. The surface acoustic wave element 2 has a structure in which at least one interdigital electrode portion and a plurality of bumps are formed on a piezoelectric substrate.

The mounting substrate 1 and the surface acoustic wave element 2 are connected by bonding the bumps 3 formed on the surface acoustic wave element 2 and the lands 4 formed on the mounting substrate 1. [ An external terminal 7 electrically connected to the land 4 via the via hole 30 is formed in the mounting substrate 1. [ The interdigital electrode portion is formed on the surface of the surface acoustic wave element 2 opposite to the mounting substrate 1. [

On the other hand, the interdigital electrode portion of the surface acoustic wave element 2 is formed, and the region where the surface acoustic wave propagates is referred to as a function portion (vibration portion) 6. The bumps 3 are formed so as to maintain a space between the mounting substrate 1 and the surface acoustic wave elements 2. [

In the surface acoustic wave device, the surface acoustic wave element 2 is covered with the encapsulation resin 5 (resin film 10) so as to be encapsulated. A gap 8 is formed between the functional portion 6 and the mounting substrate 1 so that the surface acoustic wave can be propagated.

The surface acoustic wave device having such a structure includes a step of forming the piezoelectric element 2 having the function portion 6 and the bumps 3 on the mounting substrate 1 and the step of forming the piezoelectric element 2 on the mounting substrate 1 having the external terminal 7, A step of flip-chip bonding the vibration portion to the mounting substrate through the bumps so as to face the mounting substrate, a step of disposing the resin film 5 on the mounting substrate on which the piezoelectric element is mounted, a sealing step using the resin film, And a dividing step of dicing the substrate to obtain individual piezoelectric parts.

However, there has been a problem that the size and thickness of the surface acoustic wave device can not be reduced unless the box-shaped package on which the surface acoustic wave element is mounted is small, and the cost for the small box-shaped package is high.

In addition, there is a disadvantage in that the liquid resin penetrates into the vibrating section of the surface acoustic wave element, resulting in defects. In addition, voids are generated in the liquid resin and voids are generated.

In the conventional method of forming a dam, the adhesion strength of the bump is weakened due to the variation of the height of the dam and the bump, or the size of the surface acoustic wave element is increased by the amount of forming the dam. .

Korean Patent Registration No. 561319 (Registered on Mar. 3, 2006)

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems described above and to provide a surface acoustic wave device having a hollow structure capable of enduring under conditions that are higher than conventional reliability levels by adding a material resistant to high humidity, A highly reliable surface acoustic wave element and a method of manufacturing the same.

According to an aspect of the present invention, there is provided an IDT (Inter-Digitated Transducer) vibrating portion for generating a surface acoustic wave on a substrate of a piezoelectric element, A bump is formed at a predetermined height on the pad, and the bump is flip chip bonded to the piezoelectric element through the bump so as to face the surface on which the IDT electrode part is formed A resin film is encapsulated from the mounting substrate to the piezoelectric element, and a parylene or super water-repellent coating agent is applied to the entire surface of the resin film including the mounting substrate The surface acoustic wave device is characterized in that the surface acoustic wave device is coated.

The resin film encapsulated in the piezoelectric element may be pressed and cured while heated and softened through a thermocompression process in which the mounting board on which the piezoelectric element is mounted is passed between the two rollers.

Further, the resin film may be a material having a hot-melting property and an adhesive property including an epoxy resin composition, a polyimide resin composition and a polyolefin resin composition.

In addition, an insulating layer may be formed on the substrate of the piezoelectric element so that the IDT vibrating portion and a part of the pad are exposed.

The material of the insulating film is a dielectric material including silicon nitride (SiNx) and may have a thickness of 0.01 to 0.02 탆.

According to another aspect of the present invention, there is provided a method for manufacturing a piezoelectric vibrator, comprising: (a) forming an IDT (Inter-Digitated Transducer) vibrating portion for generating a surface acoustic wave on a substrate of a piezoelectric element; step; (b) forming a plurality of pads on the substrate of the piezoelectric element so as to be spaced apart from the IDT vibrating portion at regular intervals; (c) forming a bump at a constant height on the pads; (d) mounting a ceramic substrate on the piezoelectric element via flip-chip bonding by way of the bump so that the IDT electrode portion is opposed to the surface on which the IDT electrode portion is formed; (e) sealing the resin film from the mounting substrate to the piezoelectric element; And (f) coating the entire surface of the resin film including the mounting substrate with a parylene or super water repellent coating agent.

In the step (a), the IDT oscillating portion may be formed in the form of a metal plate of a comb-stripe shape in the central region of the substrate of the piezoelectric element.

In the step (b), the plurality of pads may be formed on the substrate of the piezoelectric element so as to be spaced apart from the IDT vibrating portion.

After the step (b), an insulating film is deposited on the substrate of the piezoelectric element, and the insulating film of a plurality of pad portions where the bump is to be formed and the insulating film of the IDT oscillating portion can be removed.

Further, the resin film may be a material having a hot-melting property and an adhesive property including an epoxy resin composition, a polyimide resin composition and a polyolefin resin composition.

The step (e) may have a thermocompression process in which a roller is used and the resin film is heated, softened, and pressed.

Further, in the thermocompression bonding step, the mounting board on which the piezoelectric element is mounted may be passed through between the two rollers, and the mounting board may be fixed to a flat base.

The material of the insulating film is a dielectric material including silicon nitride (SiNx) and may have a thickness of 0.01 to 0.02 탆.

According to the present invention, it is possible to manufacture a highly reliable surface acoustic wave element that can withstand conditions that are higher than conventional reliability levels by adding a high-moisture resistant material (Parylene) to the outside of a resin film (Film Epoxy).

Further, when molding on the module, there is an advantage that the molding liquid does not permeate between the mounting substrate and the interface of the surface acoustic wave elements.

It is also possible to prevent the occurrence of defects caused by the liquid resin entering the vibrating section of the surface acoustic wave element, and to prevent the sealing failure caused by voids entering the liquid resin and voids.

1 is a cross-sectional view of a surface acoustic wave device as a conventional piezoelectric component.
2 to 8 are process flow charts for explaining a method of manufacturing a surface acoustic wave device according to the present invention.
9 is a flowchart of a method of manufacturing a surface acoustic wave device according to an embodiment of the present invention.
FIG. 10 is a graph comparing the progress of reliability by examining the characteristics of a product having perylene coating and super water-repellent coating and a conventional product according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to be limited to the particular embodiments of the invention but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Embodiments of a surface acoustic wave device and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings. In the following description with reference to the accompanying drawings, the same or corresponding components will be denoted by the same reference numerals, and redundant description thereof will be omitted.

The present invention provides a surface acoustic wave device, which is a communication filter using mechanical vibrations of a substrate, and a method of manufacturing the same. A surface acoustic wave element uses a comb-like metal formed on a substrate.

Surface acoustic wave devices generate surface acoustic waves (SAWs) on a substrate when an electrical signal is input in one direction. The mechanical vibration, called surface acoustic wave, is converted back to an electrical signal on the opposite side. If the surface acoustic wave frequency of the substrate itself is different from the frequency of the input electrical signal, the signal is not transmitted but eliminated. That is, the surface acoustic wave element becomes a BPF (bandpass filter) that allows only the frequency equal to the mechanical-material frequency possessed by the filter itself.

The surface acoustic wave device has a very narrow bandwidth to pass through compared with a filter using an artificial resonance (LC) resonance principle, so that signals of unnecessary frequencies are almost completely filtered out. Therefore, the surface acoustic wave device is used in a high-frequency circuit portion of a wireless communication circuit such as a mobile communication device or an electronic device on which a filter element is mounted.

Hereinafter, a surface acoustic wave device and a manufacturing method thereof according to the present invention will be described.

2, a surface acoustic wave device 200 according to an embodiment of the present invention includes an IDT (Inter-Digitated Transducer) vibrating unit for generating a surface acoustic wave on a substrate of a piezoelectric element 110, A bump 140 is formed on the pad 130 at a predetermined height so that the bump 140 is formed at a predetermined height from the IDT vibrating portion 120 A ceramic substrate 150 is mounted on the piezoelectric element 110 by flip chip bonding so as to face the surface on which the IDT vibrating unit 120 is formed, A resin film 160 is sealed from the piezoelectric film 110 to the piezoelectric element 110 and a parylene or super water repellent coating agent 170 is coated on the entire surface of the resin film 160 including the mounting substrate 150 .

At this time, the resin film 160 sealed in the piezoelectric element 110 is heated and softened through the thermocompression bonding process in which the mounting substrate 150 on which the piezoelectric element 110 is mounted is passed between the two rollers, and is pressed It may be in a cured state.

A via hole 190 connected to the bump 140 is formed in the mounting substrate 150 mounted on the piezoelectric element 110 by flip chip bonding.

The IDT vibrating portion 120 for generating surface acoustic waves is formed in the central region of the substrate of the piezoelectric element 110 in the form of a comb-like metal plate. Aluminum (Al) Lt; RTI ID = 0.0 > um. ≪ / RTI >

In addition, the resin film 160 may be a material having a hot-melting property and an adhesive property including an epoxy resin composition, a polyimide resin composition, and a polyolefin resin composition.

An insulating layer 180 may be formed on the substrate of the piezoelectric element 110 such that the IDT vibrating portion 120 and a plurality of pads 130 are partially exposed.

The material of the insulating film 180 is a dielectric material including silicon nitride (SiNx) and may have a thickness of 0.01 to 0.02 mu m.

Hereinafter, a method for manufacturing a surface acoustic wave device according to the present invention will be described with reference to FIGS.

As shown in FIG. 4, the IDT vibrating unit 120 is formed on the substrate of the piezoelectric device 110 in the form of a comb-like metal plate in the central region of the substrate. Aluminum (Al) may be selected as the material of the IDT vibrating section 120. A method of forming the IDT electrode portion 120 on the substrate is as follows.

A metal (for example, Al) is deposited on the entire surface of the piezoelectric element 110 to a thickness of 0.3 to 0.5 μm. Thereafter, the photoresist is etched except for the metal formed in the central region of the substrate through a photolithography process (coating / exposure / development) to form the IDT vibrating portion 120. In this process, a dry etching method using boron chloride (BCl 3), chlorine (Cl 2) gas, or the like can be selected as the etching method of the metal. Thereafter, unnecessary photoresist patterns are removed through a strip process.

Next, a plurality of pads 130 are formed on the substrate of the piezoelectric element 110 so as to be spaced apart from the IDT vibrating unit 120. The material of the pad 130 may be titanium (Ti) and gold (Au). A method of forming the pad 130 on the substrate of the piezoelectric element 110 is as follows.

A photolithography process (coating / exposure / development) using a photoresist is performed to form a photoresist pattern that protects the IDT vibrating portion 120 on the substrate. Then, a metal (for example, Ti / Au) is deposited on the entire surface of the substrate to a thickness of 0.45 to 0.55 μm. At this time, the IDT vibrating unit 120 is protected by the photoresist pattern. Therefore, the metal to be the pad 130 is formed on the entire surface of the substrate except the region where the IDT vibrating portion 120 is formed. Thereafter, the metal deposited on the surface of the substrate is peeled off by a lift-off process so as to be spaced apart from the IDT vibrating portion 120.

Next, as shown in FIG. 4, an insulating layer 180 is formed on the substrate of the piezoelectric element 110 so as to have a first opening 135 for exposing a part of the pad 130. The insulating layer 180 serves to electrically isolate the pads 130 and to expose only a part thereof. As the material of the insulating film 180, a dielectric such as silicon nitride (SiNx) may be selected. A method of forming the insulating film 180 for insulating the pads 130 is as follows.

A dielectric material (for example, SiNx) is deposited on the entire surface of the piezoelectric element 110 to a thickness of 0.01 to 0.02 μm. At this time, a plasma chemical vapor deposition apparatus (PECVD) may be used as a method of depositing the dielectric material. The inside of the chamber of the apparatus may be set to an atmosphere in which monosilane (SiH 4), ammonia (NH 3) gas, etc. are introduced. Then, a photoresist pattern is formed to expose a region where the first opening 135 is to be formed through a photolithography process (coating / exposure / development) using a photoresist. Thereafter, when the insulating layer 180 is etched, a first opening 135 is formed in a part of the insulating layer 180. In this process, a dry etching method using carbon tetrafluoride (CF 4), oxygen (O 2) gas or the like may be selected as the etching method of the insulating film 180. Thereafter, unnecessary photoresist patterns are removed through a strip process.

Next, as shown in FIG. 5, bumps 140 are formed on the plurality of pads 130 at a constant height. Here, the material of the bumps 140 may be solder, gold, conductive resin, or the like. At this time, the bumps 140 may electrically connect the piezoelectric element 110 and the mounting substrate 150, or may be for mechanically fixing the mounting substrate 150 to the mounting substrate 150. The bumps 140 may be formed so as to maintain the gap between the piezoelectric element 110 and the mounting substrate 150.

Next, as shown in FIG. 6, the piezoelectric element 110 is bonded to the piezoelectric substrate 110 through a bump 140 by flip-chip bonding to form a ceramic substrate (not shown) 150 are mounted.

Next, the resin film 160 is placed on the piezoelectric element 110 of the mounting substrate 150 on which the piezoelectric element 110 is mounted, the piezoelectric element 20 is covered with the resin film 160, The resin film 160 is thermocompression bonded to the piezoelectric element 110 and the mounting substrate 150 through the piezoelectric element 110 in which the resin film 160 is disposed between the two rollers set at the temperature and the gap 7 as shown in Fig. The resin film 160 is heated and softened by the rollers in this passage and the resin film 160 is buried in the periphery of the piezoelectric element 110 between the piezoelectric elements 110 and the resin film 160 And a laminate process for thermocompression bonding to the mounting substrate 150 is performed. Accordingly, the piezoelectric element 110 is protected through the resin film 160 produced by the laminating and curing process.

Next, as shown in FIG. 8, a mounting substrate 150 and a piezoelectric element 110 mounted on the mounting substrate 150 through the bumps 140 are formed on the entire substrate, Coating is performed with the coating agent 170. Therefore, it is possible to solve the moisture problem by this coating layer and realize a highly reliable surface acoustic wave element.

9 is a flowchart of a method of manufacturing a surface acoustic wave device according to an embodiment of the present invention.

First, an IDT (Inter-Digitated Transducer) vibration unit 120 for generating a surface acoustic wave on a substrate of the piezoelectric element 110 is formed (S910).

Next, a plurality of pads 130 are formed on the substrate of the piezoelectric element 110 so as to be spaced apart from the IDT vibrating unit 120 at regular intervals (S920).

5, an insulating film 180 is deposited on the substrate of the piezoelectric element 110 and an insulating film of a plurality of pads 130 where the bumps 140 are to be formed, (120) is removed. At this time, the material of the insulating film is a dielectric material including silicon nitride (SiNx) and may have a thickness of 0.01 to 0.02 탆.

Next, the bumps 140 are formed at a predetermined height on the plurality of pads 130 (S930).

Subsequently, a ceramic substrate 150 is mounted on the piezoelectric element 110 by flip-chip bonding through the bumps 140 so as to face the surface on which the IDT electrode unit 120 is formed (S940 ).

Next, the resin film 160 is sealed from the mounting substrate 150 to the piezoelectric element 110 (S950).

At this time, it is possible to use a roller and heat and soften the resin film 160 and press a thermocompression process.

The thermocompression bonding process can be performed by passing the mounting substrate 150 on which the piezoelectric element 110 is mounted through between the two rollers, and fixing the mounting substrate 150 to the flat base.

Further, the resin film may be a material having a hot-melting property and an adhesive property including an epoxy resin composition, a polyimide resin composition and a polyolefin resin composition.

Next, the entire surface of the resin film 160 including the mounting substrate 150 is coated with a parylene or super water repellent coating agent 170 (S960).

Here, the perylene coating is separated into individual devices through dicing, and the perylene coating is performed with the individual elements attached to the UV tape.

Therefore, in the surface acoustic wave device 200 according to the present invention, the piezoelectric element 110 is protected by the resin film 160, and is protected by the parylene or the super water repellent coating agent 170 as shown in FIG. Moisture can be prevented from being generated. FIG. 10 is a graph comparing the progress of reliability by examining the characteristics of a product having perylene coating and super water-repellent coating and a conventional product according to an embodiment of the present invention. In FIG. 10, the conventional product is a CSP type, and the product according to the present invention is prepared by perillin coating a conventional product with a thickness of 0.5 탆 or 2 탆, or by super water-repellent coating on a conventional product. As the evaluation method, the characteristics of 10 products were examined for each item, and electrical characteristics were checked after HAST (High Accelerator Stress Test) at 130 °, 85%, and 96h, and electrical characteristics were checked after FC-40 dipping. As a result of the reliability test, all four products were passable in the case of the HAST 96h test, and the comparison result of the FC-40 solution dipping result was NG after 32h in the case of the existing product as shown in FIG. 10, It can be seen that even when 1160h has elapsed, NG proceeds without occurrence. Therefore, it can be seen that the application of perillin and super water-repellent coating is effective in improving the reliability.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. Only. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

The present invention relates to a highly reliable surface acoustic wave device which can withstand a condition higher than a conventional reliability level by adding a substance resistant to high humidity to the outside covered with a resin film in the production of a surface acoustic wave device having a hollow structure, For example.

100: surface acoustic wave element 110: piezoelectric element
120: IDT vibrator 130: pad
140: Bump 150: Mounting substrate
160: Resin film 170: super water-repellent coating agent
180: insulating film 190: via hole

Claims (13)

An IDT (Inter-Digitated Transducer) vibrating portion for generating a surface acoustic wave is formed on a substrate of a piezoelectric element, a pad is formed at a predetermined distance from the IDT vibrating portion, A bump is formed on the pad at a constant height,
A ceramic substrate is mounted on the piezoelectric element by flip chip bonding so as to face the surface on which the IDT vibrating portion is formed and the resin film is sealed from the mounting substrate to the piezoelectric element,
Wherein a parylene or super water repellent coating agent is coated on the entire surface of the resin film including the mounting substrate to prevent moisture from being generated.
The method according to claim 1,
Wherein the resin film encapsulated in the piezoelectric element is in a state of being pressed and hardened while being heated and softened through a thermocompression process of passing the mounting board on which the piezoelectric element is mounted between two rollers .
3. The method according to claim 1 or 2,
Characterized in that the resin film is a material having a hot-melting property and an adhesive property, which comprises an epoxy resin composition, a polyimide resin composition, and a polyolefin resin composition.
The method according to claim 1,
Wherein an insulating film is formed on the substrate of the piezoelectric element so that the IDT vibrating portion and a part of the pad are exposed.
5. The method of claim 4,
Wherein the material of the insulating film is a dielectric material including silicon nitride (SiNx) and has a thickness of 0.01 to 0.02 占 퐉.
(a) forming an IDT (Inter-Digitated Transducer) vibrating portion for generating a surface acoustic wave on a substrate of a piezoelectric element;
(b) forming a plurality of pads on the substrate of the piezoelectric element so as to be spaced apart from the IDT vibrating portion at regular intervals;
(c) forming a bump at a constant height on the plurality of pads;
(d) mounting a ceramic substrate on the piezoelectric element via flip-chip bonding by way of the bump so that the IDT electrode portion is opposed to the surface on which the IDT electrode portion is formed;
(e) sealing the resin film from the mounting substrate to the piezoelectric element; And
(f) coating the entire surface of the resin film with a parylene or super water repellent coating, including the mounting substrate, to prevent moisture from being generated;
The surface acoustic wave device comprising:
The method according to claim 6,
Wherein the step (a) comprises forming the IDT oscillating portion in the form of a comb-shaped metal plate in the central region of the substrate of the piezoelectric element.
The method according to claim 6,
Wherein the step (b) comprises forming the plurality of pads on the substrate of the piezoelectric element so as to be spaced apart from the IDT vibrating part.
The method according to claim 6,
The method of manufacturing a surface acoustic wave device according to claim 1, wherein after the step (b), an insulating film is deposited on the substrate of the piezoelectric element, and the insulating film of a plurality of pad portions where the bump is to be formed and the insulating film of the IDT oscillating portion are removed Way.
The method according to claim 6,
Characterized in that the resin film is a material having a hot-melting property and an adhesive property, which comprises an epoxy resin composition, a polyimide resin composition, and a polyolefin resin composition.
The method according to claim 6,
Wherein the step (e) includes a thermocompression bonding step of heating and softening the resin film using a roller and pressing the resin film.
12. The method of claim 11,
Wherein the thermocompression bonding step is performed by passing the mounting board on which the piezoelectric element is mounted between two rollers, and fixing the mounting board to a flat base.
10. The method of claim 9,
Wherein the material of the insulating film is a dielectric material including silicon nitride (SiNx) and has a thickness of 0.01 to 0.02 탆.

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