JP2013123071A - Electronic component package and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose new package structure and a manufacturing method which can achieve both of package thinning and high reliability in an electronic component package where a hollow part is formed and sealed on a functional element.SOLUTION: A resin layer 4 provided with space on a functional region 2 and a metal layer are stacked. The metal layer is formed so that the same material is separated into a portion 6 forming a lid having a projection for covering the space and supporting external pressure and a portion 7 forming an external terminal. After plating the entire surface so as to fill a space part and a patterned upper resin layer 9 that is provided on lower-layer resin 4 with a through hole 8 formed, the same structure can be easily obtained by cutting into predetermined thickness.

Description

  The present invention relates to an electronic component package represented by a surface acoustic wave filter used in a high-frequency electronic circuit, in which a functional element is sealed in a hollow state, and a manufacturing method thereof.

  The package of an element that exhibits a specific electrical function by forming an electrode pattern or a fine structure on the surface of a single crystal wafer, represented by a surface acoustic wave filter, changes its characteristics when the functional part surface is covered with a resin or the like. A hollow structure is employed so that other objects do not come into contact with a particularly functionally important part of the element surface.

  FIG. 4 shows a package structure of a general surface acoustic wave filter (hereinafter referred to as SAW filter).

  For the purpose of reducing package dimensions, so-called flip chip mounting is performed in which a surface acoustic wave element (hereinafter referred to as a SAW element) 104 is mounted on a circuit board 101 with a functional surface facing the substrate side, and a material such as a resin. A structure sealed with 107 is common. On the surface of the functional part, an intermediate part 108 that is not covered with the sealing material is formed.

  The above structure is a structure in which a SAW element is cut out from a wafer into individual pieces, and then the individual elements are mounted on a substrate. For the purpose of further miniaturization, after forming a hollow sealing structure with a wafer, dicing is performed. A structure in which a package is completed by dividing it into pieces is proposed, and an example thereof is shown in FIG.

  FIG. 5 is a cross-sectional view of the element after being singulated. On the single crystal material 110 on which the functional portion 111 and the electrode 112 are formed, the resin layer 113 for forming the space 116 and the resin layer 113 are formed thereon. The circuit board 114 is bonded, and reference numeral 115 denotes an external connection terminal.

  Since the package having such a structure does not have a sealing structure surrounding the SAW element as compared with the package shown in FIG. 4, further downsizing can be achieved, and the process of mounting the SAW element on the circuit board can be omitted. This is also advantageous in terms of manufacturing cost.

  For example, Patent Document 1 is known as prior art document information relating to the invention of this application.

Special Table 2002-532934

  The package structure disclosed in the prior art shown in FIG. 5 has a problem in reliability in actual use.

  SAW filters are often used in small communication devices typified by mobile phones, but recently, functional modules on which electronic parts including SAW filters are mounted in advance are mounted on the motherboard of the device. It is common to use it.

  A functional module is an assembly of components formed so as to exhibit specific functions by mounting electronic components at high density on a small circuit board, and is sealed with resin except for external electrode portions. It is common. As the resin sealing method, the transfer mold method is most often used. In the resin molding process, a high temperature of 150 ° C. or higher and a high pressure of several MPa or higher are applied to the electronic component.

  The mounting structure disclosed in Patent Document 1 is a circuit board in which the lid of the space portion is called a printed board. In the circuit board, the surface of the fiber reinforced resin sheet is coated with a copper foil, and the circuit board does not have sufficient rigidity and strength against an external force at a high temperature.

  In the above transfer molding process, when high temperature and high pressure are applied, the circuit board forming the cover of the space part is easily deformed, the space is crushed, and the characteristics of the SAW filter are changed.

  In addition, in order to obtain a circuit board that can withstand high temperature and high pressure, it is necessary to increase the thickness, which increases the overall thickness of the package.

  In order to solve the above-described problems, the present invention has a structure in which a resin layer having a space on at least the functional region and a metal layer are laminated on a substrate on which a device having a functional region and an electrode is formed. In the electronic component package, the metal layer includes a portion that forms a lid that covers the functional region and a portion that forms an external electrode, and at least a part of the metal layer that forms the lid that covers the functional region is the A plurality of protrusions in contact with a surface of the substrate, wherein the space exists between the plurality of protrusions, and the plurality of protrusions are connected via a lid on the functional area, and the plurality of protrusions and the protrusions At least a part of the resin layer exists between the space and the space.

  The electronic component package structure of the present invention is a structure in which a resin layer having a space and a metal layer are laminated, and since the lid that covers the functional area is formed by the metal layer, it has high rigidity, and the metal lid Has protrusions that reach the surface of the substrate, and even when exposed to high temperatures and high pressures such as transfer molds, it has the effect of reducing the deformation of the space and obtaining high reliability. Therefore, the thickness of the entire package can be reduced.

  In addition, the method of manufacturing an electronic component package according to the present invention includes forming a space portion and a bottomed hole portion using a photosensitive resin layer on a substrate on which a large number of elements having functional regions and electrodes are formed on the surface. Laminating a film material such as copper foil on the entire surface of the layer, patterning so that the film material that becomes the lid of the space part remains, exposing the bottomed hole for connecting to the electrode and the bottomed hole that becomes the protrusion of the lid part, A step of depositing a metal layer on the bottomed hole and simultaneously depositing a metal layer on a film material on the space portion to simultaneously form an electrode portion and a space portion lid; And the step of dicing into individual pieces including each laminated layer, and the electrode portion and the space portion lid with protrusions can be formed at the same time, and the process is simplified.

  Further, in the step of dividing the metal layer deposited by plating into a plurality of portions, a wall made of a resin is previously formed at a location that becomes a division boundary, and after the metal layer is plated, the metal layer is not higher than the height of the resin wall. The method of dividing the metal layer by removing the metal layer to the thickness of the thick metal layer into fine patterns, which is generally impossible with the photoresist etching method used as a method of dividing the metal layer into a predetermined pattern. In addition, there is an effect that the thickness variation is very small in the wafer, that is, a package having a uniform thickness can be obtained.

Sectional drawing which shows the electronic component package in embodiment of this invention Process sectional drawing which shows the manufacturing method of the electronic component package in the embodiment Process sectional drawing which shows the manufacturing method of the electronic component package in the embodiment Cross section of conventional package Cross section of conventional package

(Embodiment)
Hereinafter, an electronic component package according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a SAW filter package in the embodiment.

  In FIG. 1, a resin layer 4 having a space portion 5 is formed on the surface of a lithium tantalate single crystal substrate 1 on which an IDT portion 2 and an electrode 3 which are functional regions are formed. A metal layer 6 made of copper is laminated.

  The connection from the electrode 3 to the external electrode 7 is performed by filling the bottomed hole 8 provided in the resin layer 4 with a metal such as copper in a protruding shape.

  Further, a protrusion 10 made of, for example, copper is formed on the metal layer 6, and the tip thereof is in contact with the surface of the substrate 1.

  The external electrode 7 is made of the same metal as the metal layer 6 that forms the lid of the space portion 5, and is separated from other electrodes and lid portions by the insulating resin layer 9.

  In the present invention, if the metal layer that forms the electrode and the intermediate cover is copper, it is particularly easy to form a plating film, and filling and plating of the bottomed hole and plating of the cover portion can be performed simultaneously. And good electrical characteristics can be obtained. In addition, if the same metal layer can be formed, it will not be limited to copper.

  When an external hydrostatic pressure is applied to the package, the space lid receives a large applied pressure, but since the metal projection 10 supports the space lid, the deformation of the space 5 is suppressed to a small level. In general, when comparing the elastic modulus of copper and photosensitive resin materials at a high temperature of 150 ° C. or higher, copper is 10 to 100 times larger and the deformation is significantly reduced compared to the case where the space is supported by resin alone. Is possible.

  Next, a manufacturing method for realizing such a package structure will be described.

  2 and 3 are cross-sectional views of the SAW filter package for explaining the process step by step.

  As shown in FIG. 2A, a photosensitive resin layer 4 is formed with a uniform thickness on the surface of a single crystal substrate 1 on which a plurality of IDT portions 2 and electrodes 3 are formed. Since the thickness of the resin layer corresponds to the height of the space portion, the thickness is determined in consideration of the package height after completion and the required pressure resistance.

  This figure shows a single crystal substrate in which two sets of IDT portions and electrodes are formed.

  Next, as shown in FIG. 2B, by utilizing the photosensitivity of the resin layer 4, a bottomed hole 18 that forms a space portion 5 on the IDT portion 2 and a connection hole on the electrode 3 is further formed. The bottomed hole 20 that forms the projection 10 of the lid on the space is formed.

  Next, as shown in FIG. 2C, the film material is bonded to the entire surface of the resin layer 4.

  In the present embodiment, a copper foil 11 having a thickness of 3 μm is used as the film material. After laminating a thin sheet-like thermosetting adhesive on the adhesive surface of the copper foil, it can be easily bonded by pressure laminating on the resin layer 4 and heating. Moreover, when an uncured epoxy resin is used for the resin layer 4, the copper foil can be bonded without using another adhesive by curing the resin layer 4 in a state where the copper foil 11 is pressed against the resin layer 4. .

  Next, as shown in FIG. 2D, when the copper foil 11 is etched by the photolithography method so as to leave only the copper foil 12 on the space 5, the bottomed holes 18 and 20 on the electrodes are opened.

  At this time, since the copper foil 11 is sufficiently thin with a thickness of 3 μm, patterning can be performed with high accuracy.

  When an adhesive sheet is used when bonding the copper foil 11 on the resin layer 4, the adhesive sheet remains on the bottomed holes 18 and 20 after the copper foil 11 is removed by etching. In this case, the bottomed holes 18 and 20 can be completely opened by introducing an ashing process using oxygen plasma or the like.

  In the method using the adhesive sheet, since the copper corrosive liquid does not enter the bottomed hole 18 when the copper foil 11 is etched, a corrosive liquid corrosive to the electrode 3 can be used. Has an effect.

  Next, as shown in FIG. 3E, a patterned resin layer 13 is provided.

  The resin layer 13 serves as a boundary that divides the plated copper layer, and is provided so that at least the bottomed hole 18 on the electrode, the copper foil 12 on the space 5, and the bottomed hole 20 for protrusion are exposed.

  Moreover, since the copper foil 12 and the bottom hole 20 for protrusions on the space part 5 need to become a series of metal parts after copper plating, they are the same area that is not divided by the resin layer 13.

  The thickness of the resin layer 13 is a value equal to or greater than the copper thickness required on the space portion 5.

  The copper thickness required on the space 5 is a value determined from the pressure resistance required for the completed electronic component package.

  Next, as shown in FIG. 3F, a metal thin film 14 to be a plating electrode in the next step is formed. In this embodiment, a total of 300 nm of a titanium film and a copper film is formed by sputtering.

  The metal thin film 14 needs to be formed inside the bottomed hole 18 on the electrode, the surface of the electrode 3, and also inside the bottomed hole 20 for protrusion.

  Next, as shown in FIG. 3G, a copper layer 15 is formed by plating on the entire surface using the metal thin film 14 formed in the previous step as a plating electrode. As the copper layer thickness at this time, at least the inside of the bottomed hole 18 on the electrode and the inside of the bottomed hole 20 for protrusion are filled, and a copper layer having a thickness greater than the final required thickness is formed on the space 5. It is necessary to

  Next, as shown in FIG. 3H, the surface of the copper layer 15 formed by plating is cut, and the copper deposited on the resin layer 13 is removed. Cutting is performed until the resin layer 13 is exposed.

  As a result, the plated copper layer formed on the entire surface is divided into a plurality of portions by the resin layer 13. The divided portions correspond to the plurality of external connection electrodes 16 and the lid 17 on the space portion 5.

  At this time, the lid 17 on the space portion 5 and the copper plated and filled in the bottom hole 20 for projection are integrated, and the lid 17 on the space portion 5 is supported by the projection 10 on the substrate surface. Yes.

  Further, if an electrode is provided on the surface of the substrate in contact with the protrusion 10, the electrode and the lid 17 on the space 5 are also electrically connected via the protrusion 10, and the lid 17 on the space 5 is connected to the external connection electrode. It can also serve as.

  Thus, the plated copper layer 15 can be divided into fine patterns while having a sufficient thickness for protecting the space 5 from external pressure.

  Next, as shown in FIG. 3 (i), dicing is performed and the package is completed.

  In this embodiment, a surface acoustic wave filter (SAW) element is used. However, the present invention is not limited to this, and other objects such as an acceleration sensor element and an angular velocity sensor element have a functional structure on the surface. Therefore, it can be applied to a package in which the element surface is kept hollow.

  As described above, the electronic component package structure of the present invention can be applied to a package in which the element surface is maintained in a hollow state, and is small and highly reliable.

  In addition, the manufacturing method of the electronic component package of the present invention can form a metal layer having a sufficient thickness that can withstand external pressure, and can divide the metal layer into fine portions to form electrodes. A reliable and small electronic component package is provided with a small number of processes.

DESCRIPTION OF SYMBOLS 1 Single crystal substrate 2 IDT part 3 Electrode 4 Resin layer 5 Space part 6 Metal layer (lid part)
7 Metal layer (external electrode part)
8 Bottomed hole 9 Insulating resin layer 10 Protrusion

Claims (5)

An electronic component package having a structure in which a resin layer having at least a space on the functional region and a metal layer are laminated on a substrate having an element having a functional region and an electrode formed on the surface, wherein the metal layer includes: A portion that forms a lid that covers the functional region, and a portion that forms an external electrode, and at least a portion that forms the lid that covers the functional region of the metal layer has a plurality of protrusions in contact with the surface of the substrate;
The space exists between the plurality of protrusions and the plurality of protrusions are connected via a lid on the functional area,
An electronic component package, wherein at least a part of the resin layer exists between the plurality of protrusions and the space. A step of forming a photosensitive resin layer on a substrate on which a device having functional regions and electrodes is formed, and a space by removing the functional region and the resin layer on the electrodes by utilizing photosensitivity by development. The bottomed hole portion by removing the film material leaving at least a portion covering the space portion, the step of producing the bottom portion and the bottomed hole portion, the step of laminating the film material on the surface of the photosensitive resin layer, And a metal layer deposited on the bottomed hole by plating, and a metal layer other than the bottomed hole is deposited to cover the functional area on the space. And a step of forming at least a part thereof. 3. The method of manufacturing an electronic component package according to claim 2, wherein the film material is a copper foil with an adhesive film, and the metal layer to be plated is copper. 3. The method according to claim 2, further comprising the step of dividing the deposited metal layer into a region including at least the lid and a part of the bottomed hole portion and a region including another bottomed hole portion. Electronic component package manufacturing method. In the step of dividing the deposited metal layer into at least the upper part of the space part, a part of the bottomed hole part, and a region including the other bottomed hole part, a wall made of a resin is previously provided at a place serving as a dividing boundary. 5. The method of manufacturing an electronic component package according to claim 4, wherein the metal layer is divided by removing the metal layer up to a height of the resin wall after forming and plating the metal layer.

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