KR20060116894A - Surface acoustic wave device package and method of manufacturing the same - Google Patents

Abstract

A surface acoustic wave device package and a method for manufacturing the same are provided to prevent moisture from being infiltrated into an airtight space by protecting the SAW device package through a ring-shape metal plated layer and a metal shield layer. In a surface acoustic wave device package(100), a via substructure is formed inside a multi-layer wiring substrate(101). A SAW(Surface Acoustic Wave) chip(107) is bonded at a surface of the multi-layer wiring substrate(101) as a flip chip type. A ring-shape metal plated layer(104) is formed at the surface of the multi-layer wiring substrate(101), along an outline of the SAW chip(107). A protective film(106) forms an airtight space by surrounding the SAW chip(107). A metal shield layer(116) formed at a surface of the protective film(106) is connected with the ring-shape metal plated layer(104).

Description

Surface Acoustic Wave Device Package and Method of Manufacturing the Same

1 is a cross-sectional view of a conventional surface acoustic wave (SAW) device package.

2 is a cross-sectional view of a SAW device package according to one embodiment of the invention.

3 to 8 are cross-sectional views illustrating a method of manufacturing a SAW device package according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: SAW device package 101: multilayer wiring board

104: toroidal metal plating layer 106: protective film

107: SAW chip 108: bump

109: connection terminal 110: via

116: metal shielding layer 120: external connection terminal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave (SAW) device package and a method of manufacturing the same, and more particularly, to a surface acoustic wave device package and a method of manufacturing the same which can effectively block external moisture penetration and are resistant to thermal shock.

In general, surface acoustic wave (SAW) devices are electronic devices using surface acoustic waves generated by piezoelectric properties. SAW devices have been widely used in the application of RF components such as resonators, filters or duplexers. Such surface acoustic wave devices are manufactured and used in package form. In particular, SAW device packages in the form of Chip Size Packages (CSPs) are widely used according to the miniaturization requirements of SAW device applications. US 2003/0006863 discloses a CSP type SAW device package having a spacer provided between a piezoelectric substrate and a package substrate of a SAW chip.

1 is a cross-sectional view showing a conventional CSP type SAW device package 10. Referring to FIG. 1, a SAW chip 17 in which metal bumps 18 are provided on a ceramic package substrate 11 in which connection wires are embedded is flip chip bonded. By this flip chip bonding, the electrode of the SAW chip 17 is connected to the connection terminal 19 formed on the surface of the ceramic package substrate 11. The protective molding resin 15 is covered outside the SAW chip 17 mounted on the ceramic package substrate 11. In order to form an airtight space isolated from the external environment, an annular sealing dam 13 made of resin or metal is provided between the edge of the SAW chip 17 and the surface of the ceramic substrate 11. The lower surface of the package substrate 11 is provided with an external connection terminal 20 for electrical connection with an external wiring (for example, a connection pad of a PCB substrate).

In order to manufacture such a conventional CSP type SAW package 10, an annular sealing dam 13 made of resin or metal should be installed, and the installation process of the sealing dam 13 for securing a gas tight space is difficult. , Costly to install. In addition, since the package substrate 11 in which the connection wirings are embedded is made of a ceramic substrate, the processing of the package substrate 11 is difficult and the material cost of the package product is high.

In addition, the ceramic substrate has a coefficient of thermal expansion of about 7 ppm / K and a large difference in coefficient of thermal expansion from the SAW chip 17 having a thermal expansion coefficient of about 15 ppm / K. Accordingly, the metal bumps 18 easily fall off during a sudden temperature change such as thermal shock. In addition, it is difficult to secure the airtight space only with the sealing dam 13 and the molding resin 15, and moisture can penetrate into the electrodes of the SAW chip 17 from the outside and cause element defects.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a SAW device package that can effectively block moisture penetration from the outside, is easy to manufacture, and resistant to thermal shock.

In addition, another object of the present invention is to provide a method of manufacturing a SAW device package that can easily produce a SAW device package excellent in moisture resistance and strong thermal shock in high yield.

In order to achieve the above technical problem, a SAW device package according to the present invention, the via structure is a multi-layer wiring board is formed therein; A SAW chip flip-chip bonded onto the multilayer wiring substrate; An annular metal plating layer formed on the multilayer wiring substrate along an outer portion of the SAW chip; A protective film covering the SAW chip to form an airtight space; And a metal shielding layer formed on the protective film and connected to the annular metal plating layer.

According to a preferred embodiment of the present invention, the multilayer wiring board is a polymer substrate such as BT resin. Further, preferably, the via structures formed in the multilayer wiring board are vertically connected to be offset from each other. As described above, the via structures are vertically connected to be offset from each other instead of extending in a vertical straight line, thereby more effectively blocking external moisture penetration.

According to a preferred embodiment of the present invention, the protective film is a thermosetting resin film. For example, a polyimide film or an epoxy film can be used as the protective film.

In addition, the annular metal plating layer is preferably connected to the ground terminal of the multilayer wiring board. As such, the annular metal plating layer is connected to the ground terminal, so that the metal shielding layer is connected to the ground terminal. Accordingly, the metal shielding layer provides a shielding effect against external electromagnetic waves. Preferably, the metal shielding layer is formed by sputtering and electroplating.

In order to achieve another object of the present invention, a method for manufacturing a SAW device package according to the present invention, comprising the steps of preparing a multi-layer wiring board having a plurality of via structures formed therein; Forming annular metal plating layers along the periphery of the SAW chip mounting position on the multilayer wiring board; Mounting a plurality of SAW chips on the multilayer wiring substrate by flip chip bonding; Stacking a protective film on a front surface including the mounted plurality of SAW chips to form an airtight space; Removing the protective film along a boundary between SAW devices to form a dividing groove exposing the annular metal plating layer; Forming a metal shielding layer on the protective film and the exposed annular metal plating layer; Cutting the resultant formed metal shielding layer into individual SAW devices.

Preferably, the via structure inside the multilayer wiring board is formed to be vertically connected to be offset from each other. Via structures that are vertically connected to each other are advantageous in suppressing external moisture penetration. In addition, the multilayer wiring board is preferably formed of a polymer system such as BT resin. By forming the multilayer wiring board in a polymer system, it is possible to minimize bump damage due to thermal shock, which has been a conventional problem.

Preferably, the annular plating layer is formed to be connected to the ground terminal of the multilayer wiring board. In this way, the metal shielding layer is electrically connected to the ground terminal through the annular plating layer, thereby obtaining an external electromagnetic shielding effect.

According to an embodiment of the present disclosure, the mounting of the plurality of SAW chips on the multilayer wiring board may include forming a stud bump of a material such as gold (Au) on the surface of the SAW chip; Bonding the stud bumps to the multilayer wiring substrate using ultrasonic waves.

According to another embodiment of the present disclosure, the mounting of the plurality of SAW chips on the multilayer wiring board may include forming solder bumps of AuSn or the like on the multilayer wiring board; Bonding the SAW chip to the solder bumps by thermal fusion.

Preferably, the step of laminating the protective film is carried out by laminating a protective film made of a thermosetting resin by thermocompression bonding. In this case, as the thermosetting resin, polyimide resin or epoxy resin may be used.

Preferably, the forming of the dividing groove may be performed by irradiating a laser to the protective film along a boundary between SAW devices. By using such laser irradiation, the division grooves can be safely formed without damaging the annular metal plating layer.

According to an embodiment of the present invention, the forming of the metal shielding layer may include forming a seed metal film on the protective film by sputtering; Performing electroplating on the seed metal film.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity, and the elements denoted by the same reference numerals in the drawings are the same elements.

2 is a side cross-sectional view of a SAW device package according to one embodiment of the invention. Referring to FIG. 2, the SAW device package 100 includes a multilayer wiring board 101 and a SAW chip 107. The via structure 110 is formed in the multilayer wiring board 101. The SAW chip 107 is flip chip bonded to the connection terminal 109 of the multilayer wiring board 101 through the bump 108. In order to provide an airtight space between the SAW chip 107 and the multilayer wiring board 101, a protective film 106 made of a thermosetting resin such as polyimide or epoxy is covered on the SAW chip.

On the multilayer wiring board 101, an annular metal plating layer 104 is formed along the outer portion of the SAW chip 107. In addition, a metal shielding layer 116 is formed on the protective film 116 and connected to the annular metal plating layer 104. The annular metal plating layer 104 and the metal shielding layer 116 effectively block external moisture penetration into the airtight space. Preferably, the metal shielding layer 116 is formed by sputtering and electroplating. That is, the metal shielding layer 116 can be formed by forming a seed metal film covering the protective film 106 through sterling and electroplating thereon.

Preferably, the annular metal plating layer 104 is connected to the ground terminal of the multilayer wiring board 101. In this way, the metal shielding layer 116 is electrically connected to the ground terminal through the annular metal plating layer 104, thereby obtaining a shielding effect against external electromagnetic waves.

Preferably, the multilayer wiring board 101 is a polymer substrate such as BT resin. By using the polymer substrate as the multilayer wiring board 101 as described above, it is possible to prevent the bump from being separated due to the conventional thermal shock. That is, since the thermal expansion coefficient of the polymer-based multilayer wiring board 101 is 12-15 ppm / K and the difference is not large from the thermal expansion coefficient of the SAW chip 107, the deformation of the substrate 101 does not occur even when the temperature changes such as thermal shock. It does not occur much. Therefore, since the multilayer wiring board made of a polymer material exhibits strong thermal shock characteristics, adhesion of the metal bumps 108 is stable.

In addition, since the multilayer wiring board 101 has a multilayer structure, it is possible to suppress external moisture penetration. In particular, as shown in FIG. 2, since the via structures 110 formed inside the substrate 101 are vertically connected to be offset from each other, moisture penetration from the outside is further blocked.

Hereinafter, a method of manufacturing a SAW device package according to an embodiment of the present invention will be described with reference to FIGS. 3 to 8. By using the manufacturing method of this embodiment, multiple SAW device packages can be obtained simultaneously from a single wiring board.

First, referring to FIG. 3, a polymer-based multilayer wiring board 101 having a via structure 110 formed therein is prepared. Connection terminals 109 connected to vias are formed on the surface of the multilayer wiring board 101, and external connection terminals 120 are formed on the bottom surface of the multilayer wiring board 101. As described above, the via structure 110 is formed to be vertically connected to be offset from each other. Thereafter, the annular metal plating layer 104 is formed along the periphery of the SAW chip mounting position on the multilayer wiring board 101. The annular metal plating layer 104 is formed to be connected to the ground terminal (not shown) of the substrate 101.

Next, referring to FIG. 4, a plurality of SAW chips 107 are mounted through metal bumps 108 at SAW chip mounting positions on the multilayer wiring board 101 by flip chip bonding. Flip chip bonding for mounting the SAW chip 107 may be performed by forming a gold stud bump on the SAW chip surface and ultrasonic bonding.

Alternatively, the flip chip bonding may be performed by forming solder bumps of AuSn material on the multilayer wiring substrate 101 and thermally bonding them. In this case, a material having a high rigidity is used as the material of the multilayer wiring board 101, and a film of gold material (Au) is coated on the ground terminal to be flip chip bonded to a thickness of 0.5 μm or more. In addition, the adhesive force of the metal bumps may be improved by heating the bonding portion at 120-180 ° C. during flip chip bonding.

Next, as shown in FIG. 5, the protective film 106 is laminated on the front surface including the plurality of SAW chips 107 by thermocompression bonding. Accordingly, the protective film 106 forms a gas tight space on the operating surface of the SAW chip 107 by flow control through temperature control. As the protective film 106, a thermosetting resin film is used. For example, a polyimide resin film or an epoxy resin film may be used. In FIG. 5, reference numeral A denotes one SAW device area.

Important factors in lamination of the protective film 106 include a crimping material, temperature, time, and vacuum degree, and when the protective film 106 is used as a polyimide-based thermosetting film, the elasticity of the crimping material as a lamination condition is 0.2. About 1 MPa, the temperature is between 170 ° C and 200 ° C, the time is 30 seconds to 2 minutes, the optimum lamination results can be obtained at a vacuum degree of 0.5 to 1.5 hpa.

Next, as shown in FIG. 6, by removing the protective film 106 along the boundary line between the SAW device regions, the division grooves exposing the annular metal plating layer 104 are formed. Preferably, division groove formation is performed by laser irradiation. That is, by irradiating a laser along the boundary line between SAW device regions, the protective film 106 near the boundary line is removed. By using such laser irradiation, the division grooves can be safely formed without damaging the annular metal plating layer 104. Alternatively, the dividing groove may be formed through a dicing process.

Next, as shown in FIG. 7, the metal shielding layer 116 is formed on the protective film 106 and the exposed annular metal plating layer 104. Accordingly, all SAW device regions are completely covered by the metal shielding layer 116, and the annular metal plating layer 104 is connected with the metal shielding layer 116. At this time, since the annular metal plating layer 104 is connected to the ground terminal, the metal shielding layer 116 is electrically connected to the ground terminal. As a method of forming the metal shielding layer 116, a seed metal layer may be formed on the protective film 106 by sputtering and then electroplated thereon.

Next, the resultant formed metal shield layer 116 is cut into individual SAW devices as shown in FIG. 8. As a result, multiple SAW device packages are obtained simultaneously. Therefore, the manufacturing method of this embodiment is suitable for mass-producing SAW device packages.

It is intended that the invention not be limited by the foregoing embodiments and the accompanying drawings, but rather by the claims appended hereto. In addition, it will be apparent to those skilled in the art that the present invention may be substituted, modified, and changed in various forms without departing from the technical spirit of the present invention described in the claims.

As described above, according to the present invention, there is no need to form a conventional sealing dam, so the SAW device package manufacturing process is relatively simple and easy. Moreover, the moisture resistance of SAW device package is high by using a multilayer wiring board. In particular, by adopting the internal via structure connected vertically to be offset from each other, the moisture resistance becomes higher. Furthermore, since the annular metal plating layer and the metal shielding layer connected to each other serve as a protective film for the entire SAW device package, it is possible to fundamentally prevent moisture penetration into the airtight space.

In addition, by using a polymer-based multilayer wiring board rather than a conventional ceramic substrate, the thermal expansion coefficient difference between the package substrate and the SAW chip is reduced to provide a structure that is resistant to thermal shock. As a result, the adhesion of the metal bumps is safely maintained even with a sudden temperature change, and the product yield is improved. In addition, by using an inexpensive polymer substrate instead of an expensive ceramic substrate, it is possible to reduce the manufacturing cost of the SAW device package. In addition, the metal shielding layer is connected to the ground terminal, thereby obtaining a shielding effect against external electromagnetic waves.

Claims (16)

A multilayer wiring board having a via structure formed therein; A SAW chip flip-chip bonded onto the multilayer wiring substrate; An annular metal plating layer formed on the multilayer wiring board along an outer portion of the SAW chip; A protective film covering the SAW chip to form an airtight space; And And a metal shielding layer formed on the protective film and connected to the annular metal plating layer. The method of claim 1, And said multilayer wiring substrate is a polymer substrate. The method of claim 1, The via structure is a surface acoustic wave device package, characterized in that connected to each other perpendicularly to each other. The method of claim 1, The protective film is a surface acoustic wave device package, characterized in that the thermosetting resin film. The method of claim 4, wherein The protective film is a surface acoustic wave device package, characterized in that the polyimide film or an epoxy film. The method of claim 1, And the annular metal plating layer is connected to a ground terminal of the multilayer wiring board. The method of claim 1, And said metal shielding layer is formed by sputtering and electroplating. Preparing a multi-layered wiring board having a plurality of via structures formed therein; Forming annular metal plating layers along the periphery of the SAW chip mounting position on the multilayer wiring substrate; Mounting a plurality of SAW chips on the multilayer wiring substrate by flip chip bonding; Stacking a protective film on a front surface including the mounted plurality of SAW chips to form an airtight space; Removing the protective film along boundary lines between SAW devices, thereby forming a division groove exposing the annular metal plating layer; Forming a metal shielding layer on the protective film and the exposed annular metal plating layer; And And cutting the resultant in which the metal shielding layer is formed into individual SAW devices. The method of claim 8, The via structure inside the multilayer wiring board is formed so as to be vertically connected to be offset from each other. The method of claim 8, And said multilayer wiring board is formed of a polymeric material. The method of claim 8, And the annular plating layer is formed to be connected to a ground terminal of the multilayer wiring board. The method of claim 8, Mounting a plurality of SAW chips on the multilayer wiring board, Forming stud bumps on the SAW chip surface; And Adhering the stud bumps on the multilayer wiring substrate using ultrasonic waves. The method of claim 8, Mounting the plurality of SAW chips on the multilayer wiring board, Forming solder bumps on the multilayer wiring substrate; And And bonding the SAW chip to the solder bumps by thermal fusion. The method of claim 8, Laminating the protective film, the method of manufacturing a surface acoustic wave device package, characterized in that carried out by laminating a protective film made of a thermosetting resin by thermocompression bonding. The method of claim 8, The forming of the dividing groove may be performed by irradiating a laser to the protective film along a boundary line between SAW devices. The method of claim 8, Forming the metal shielding layer, Forming a seed metal film on the protective film by sputtering; And And electroplating on the seed metal film.

Images