JP2006237405A - Electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component in which the package size is reduced while applying such a sealing structure as a predetermined space is formed to surround an element function section. <P>SOLUTION: The electronic component comprises: an element substrate 3 having an element function section 1; a dam 8 formed to surround the element function section 1; a cap 9 bonded to the dam 8 and forming an air gap 10 on the inside; a circuit board 5 mounted on the element substrate 3 and connected electrically therewith; and a resin 11 sealing the element substrate 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic component device capable of hermetically sealing, for example, an FBAR filter.

In the SAW filter and the FBAR filter, a sealing structure is employed in order to protect the element function portion from the influence of the outside world, as in a normal semiconductor device. However, the SAW filter and the FBAR filter must form a predetermined space so as to surround the element function unit due to their operating characteristics. With respect to such a point, the following sealing structure is exemplified as a conventional sealing structure. For example, in Patent Document 1, as shown in FIG. 5, a SAW chip 52 is mounted and fixed to a package 51 with a die bond material 53, and input / output signal terminals (electrode pads) 54 and wire pads 55 of the SAW chip 52 are connected to Au. Alternatively, a structure is described in which the wires are electrically connected by a bonding wire 56 made of a thin wire such as Al, and the cap 51 is hermetically sealed from above the package 51.
Japanese Patent Laid-Open No. 7-212181

  However, the conventional sealing structure as described above needs to secure a wire space in order to avoid a short-circuit failure between the cap and the bonding wire, and requires a larger package than the SAW chip. For this reason, there has been a problem that the area and volume of the package are increased, and it is impossible to meet the recent demands for reducing the package size.

  The present invention has been made to cope with such a problem, and it is possible to reduce the package size after applying a sealing structure in which a predetermined space is formed so as to surround the element function unit. It is an object of the present invention to provide an electronic component device.

  An electronic component device according to an aspect of the present invention includes an element substrate having an element function part, a dam formed so as to surround the element function part, and a cap that is joined to the dam and forms a gap inside the dam. And a circuit board on which the element substrate is mounted and electrically connected to the element substrate, and a sealing resin for sealing the element substrate.

  In an electronic component device according to an aspect of the present invention, a dam that can be adjusted to a predetermined height is provided on an element substrate on which an element function unit is formed, and a cap is joined to the dam so as to surround the element function unit. Thus, the package size can be reduced after forming a predetermined space necessary for the operating characteristics of the element function unit.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, although embodiment of this invention is described based on drawing below, those drawings are provided for illustration and this invention is not limited to those drawings.

  FIG. 1 is a cross-sectional view showing a cross section of the electronic component device according to the first embodiment of the present invention.

 In the electronic component device shown in the figure, an element function unit 1 and an electrode pad 2 connected to the element function unit 1 via wiring are formed on an element substrate 3 made of a Si substrate. The element substrate 3 has a cavity structure, and a hollow part 4 is provided on the back side of the element function part 1. The circuit board 5 is mechanically (structurally) bonded to the element substrate 3 with an epoxy-based die bond material 6 so that the hollow portion 4 is sealed from below, and the circuit board is further connected via bonding wires 7. 5 and the element substrate 3 are also electrically connected. On the other hand, the element function unit 1 is surrounded by a dam 8. A cap 9 is joined to the dam 8 to seal the element function unit 1 so that a gap 10 is formed above the element function unit 1. Then, it is covered with a sealing resin 11. An external electrode 12 is provided on the back surface of the circuit board 5, and electric signals are input / output between the element function unit 1 and the outside via the bonding wires 7. In such an electronic component device, the dam 8 structurally (mechanically) joins the element substrate 3 and the cap 9 and further prevents the sealing resin 11 from entering.

  The element function unit 1 is an FBAR filter in which a piezoelectric film is sandwiched between electrodes. By applying an electrical signal between the upper and lower electrodes, a bulk wave is generated in the piezoelectric film to resonate. Specifically, an electric signal is applied to one electrode of the element function unit 1 and converted into a bulk wave to be transmitted through the piezoelectric film. Furthermore, the bulk wave that has reached the other electrode of the element function unit 1 is converted again into an electric signal and can be extracted outside. The metal used as the material of the upper and lower electrodes in the element function unit 1 is made of Al (aluminum) or an alloy containing Al as a main component. In the latter case, copper or silicon can be added.

  The element substrate 3 has a cavity structure, and a hollow part 4 is formed on the back side of the element function part 1. The hollow portion 4 is provided on the element substrate 3 from the surface opposite to the element function portion 1 by the RIE method or the like. By providing the hollow portion 4, the operating characteristics of the element function portion 1 are ensured. The hollow portion 4 is the same as the thickness of the element substrate 3 and is about 150 μm. Further, the element function portion 1 is formed with a gap 10 sealed so as to surround the upper portion with a dam 8.

  The dam 8 has a function of forming an air gap 10 so as to surround the element function unit 1 and preventing the sealing resin 11 from entering. The dam 8 can be formed of, for example, a thermosetting resin such as an epoxy resin, a polyimide resin, or a phenol resin. In addition, as a constituent material of the dam 8, it is also possible to apply a low melting point metal such as solder and gold tin, or a combination of a low melting point metal and a thermosetting resin. Further, the air gap 10 is determined by the height of the dam 8. The height of the dam 8 is preferably in the range of 2 to 10 μm. In order to obtain such a predetermined height, it is preferable that the dam 8 is produced by mixing, for example, spherical fine particles such as silica and alumina as a spacer in a thermosetting resin. As the thermosetting resin, a resin that can be B-staged is preferable because the resin adheres closely to the cap 9 when the cap 9 is joined, and both can be easily bonded by a subsequent heating step. On the other hand, the average particle size of the spacer is preferably in the range of 2 to 30 μm. When the particle size is less than 2 μm, when pressure is applied to the cap 9 joined to the dam 8, the dam 8 is crushed and the predetermined height cannot be maintained. When the particle diameter exceeds 30 μm, for example, when a square dam is formed by coating on the element substrate 3 by screen printing, it may cause clogging of the mask. By adding a spacer to the thermosetting resin in this way, the shape of the dam 8 is maintained without being crushed even when the cap 9 bonded to the dam 8 is pressurized when heated by applying pressure in the manufacturing process. The gap 10 having a height of about 2 μm can be formed above the element function unit 1 above the element function unit 1.

  The bonding wire 7 is made of a fine wire such as Au or Al, and connects the electrode pad 2 on the element substrate 3 and the wire pad 13 on the circuit substrate 5. Via this bonding wire 7, an electric signal is input / output between the element function unit 1 connected to the electrode pad 2 by wiring and the outside.

  The circuit board 5 is a board having a role of inputting / outputting electric signals to / from the outside, and protects the element function unit 1 from external force, moisture, water, etc., and further forms a basis for forming a form. is there. A copper-clad laminate is used for the circuit board 5, and a wiring pattern is formed on the copper foil. Further, an external electrode 12 formed by laminating a Ni film and an Au film by metal plating is provided on the back surface of the circuit board 5, and the external electrode 12 passes through a conductor provided through the circuit board. Are connected to the wire pad 13. The wire pad 13 is a laminated film made of the same Ni film and Au film as the external electrode 12.

  The sealing resin 11 is a protective film having a function of protecting the composite body composed of the element substrate 3, the cap 9 and the circuit substrate 5 from environmental stress and mechanical stress. As the sealing resin 11, for example, a thermosetting resin such as an epoxy resin or a polyimide resin can be used.

  The electronic component device as described above is manufactured as follows, for example.

  First, the electrode pad 2 and the wiring connecting the element function unit 1 and the electrode pad 2 are formed on the element substrate 3 (thickness 150 μm) on which the element function unit 1 is formed by a sputtering method. Specifically, an Al film having a thickness of about several hundred nm is formed on the element substrate 3 using a magnetron type sputtering apparatus. A resist film is formed on the Al film, and the resist film is exposed and developed by photolithography. Then, the Al film is selectively etched by reactive ion etching (RIE) using this resist film as a mask. Next, an opening is provided in the element substrate 3 from the surface opposite to the element function unit 1 by the RIE method.

  Next, a dam material is applied in a square shape at a position where the dam 8 is formed on the element substrate 3 using a screen printing method so as to surround the element function unit 1. The dam material is prepared by adding a spacer made of silica having a particle size of 5 ± 1 μm to the epoxy resin. The height of the dam 8 to be applied is preferably 4 to 6 μm.

  After drying at a low temperature of 100 ° C. or lower, a cap 9 (thickness of about 100 μm) made of a Si substrate is brought into contact with the dam 8 in the B stage state and temporarily attached.

  On the other hand, the wire pad 13 is formed in the circuit board 5 which consists of a copper clad laminated board (copper foil 0.028mm) in which the wiring pattern was formed. Specifically, the wire pad 13 is formed by laminating a Ni film and an Au film by metal plating on the circuit board 5 having a wiring pattern. Next, a through hole is formed and a conductor is provided through a predetermined position where the wire pad 13 is formed. An external electrode 12 is formed on the back surface of the circuit board 5 in the same manner as the wire pad 13 and is connected to this conductor.

  Subsequently, the element substrate 3 with the cap 9 temporarily attached is temporarily attached to the circuit substrate 5 with an epoxy-based die bond material 6 so as to seal the opening provided in the element substrate 3. Here, an epoxy resin is used for the die bond material 6; however, it is also possible to apply a low melting point metal such as solder or gold tin or a combination of a low melting point metal and a thermosetting resin.

  Thereafter, the composite composed of the element substrate 3, the cap 9 and the circuit board 5 is heated to bond the cap 9 and the circuit board 5 to the element substrate 3, respectively. When the thermosetting component of the dam 8 having the thermosetting resin is heated to the curing temperature, the frame dam 8 having a thickness of 5 μm and a width of 10 μm is formed. The dam 8 prevents the sealing resin 11 from entering the gap 10 and connects the element substrate 3 and the cap 9 structurally (mechanically). The above-described heating of the composite may be performed while applying an appropriate pressure using a press facility, or using a constant temperature furnace, a hot plate, or the like while pressing with a weight or the like as necessary. Also good.

  After the cap 9 and the circuit board 5 are bonded to the element substrate 3 in this way, the electrode pad 2 and the wire pad 13 are connected by the bonding wire 7 (Au wire). By performing this wire bonding, the element substrate 3 and the circuit substrate 5 are electrically connected. In other words, the element function unit 1 connected to the electrode pad 2 via the wiring and the external electrode 12 connected to the wire pad 13 are electrically connected.

  After wire bonding, sealing is performed using a thermosetting resin (sealing resin) so that the back surface of the circuit board 5 on which the external electrodes 12 are formed is exposed. Specifically, the element substrate 3 is coated with a resin by applying an epoxy resin and curing the applied resin by applying a predetermined heat treatment. At this time, a dam 8 is formed between the cap 9 and the element substrate 3, and the periphery of the element function unit 1 is surrounded by the dam 8, so that the sealing resin 11 is a gap between the cap 9 and the element substrate 3. The operation characteristics of the element function unit 1 are protected.

  In this manner, a structure is obtained in which the upper side of the element function unit 1 is sealed with the cap 9 and the lower side of the element function unit 1 is sealed with the circuit board 5. According to such a sealing structure, the upper and lower sides of the element function unit 1 are protected by the predetermined space, and the operation characteristics are not impaired.

  That is, as shown in the first embodiment, when an FBAR filter is applied to the element function unit 1, a space for vibrating the element function unit 1 is required. A space sealed up and down can be formed.

  Further, as the dam 8, a spacer is added to the thermosetting resin, and the height thereof is adjusted to a range of 2 to 10 μm, thereby forming a gap 10 of about 2 μm above the element function unit 1. It is possible to package with a size close to the limit. That is, the package can be reduced in size.

  The above-described bonding between the element substrate 3 and the circuit substrate 5 can be performed by a relatively low temperature apparatus using a readily available die bond material such as an epoxy resin. Therefore, expensive and special equipment is not required.

  Further, since the Si substrate is applied to the cap 9, the thermal expansion coefficient can be made uniform with respect to the temperature change, and a structure that is resistant to deformation such as warpage can be obtained.

  Here, FIG. 1 shows a structure in which the die bonding material 6 is applied to the entire back surface of the element substrate 3 having the element function unit 1 and bonded to the circuit board 5. As shown in FIG. A structure may be used in which the opening provided on the back side of the element is sealed with a semiconductor substrate 22 (thickness: 100 μm) made of a Si substrate in a dam 21 formed on the back surface of the element substrate 3 to form the hollow portion 23. . Thus, by forming the hollow part 23 on the back side of the element function part 1, the die bond material 6 does not adhere to the element function part 1 in the manufacturing process, and the element function part 1 can be protected. The dam 21 formed on the back surface of the element substrate 3 is the same as the dam 8 described above.

  Next, a second embodiment of the present invention will be described with reference to FIG. The same elements as those in the electronic component device shown in FIG.

  As in the first embodiment, the electronic component device of the second embodiment shown in FIG. 3 includes an element function unit 1 and an electrode pad 2 connected to the element function unit 1 via a wiring. Formed on the element substrate 3. The element substrate 3 has a cavity structure, and a hollow portion 31 is formed so as to seal the opening with the semiconductor substrate 3. Metal bumps 33 are formed on the electrode pads 2 provided on the element substrate 3. On the other hand, a wiring pattern is formed on the circuit board 5 and disposed so as to face the electrode pads 2 of the element substrate 3 with the metal bumps 33 interposed therebetween. The element substrate 3 is sealed with the sealing resin 11. An external electrode 12 is provided on the back surface of the circuit board 5, and electric signals are input / output to / from the element function unit 1 through the metal bumps 33. In this way, by applying flip chip bonding to the bonding of the element substrate 3 and the circuit board 5, the element substrate 3 and the circuit board 5 are electrically and mechanically (structurally) via the metal bumps 33. Connected.

  4A to 4C are main process cross-sectional views illustrating a method of manufacturing the electronic component device shown in FIG. Detailed description of elements similar to those of the electronic component device shown in FIG. 1 is omitted.

  First, the electrode pad 2 and the wiring for connecting the element function unit 1 and the electrode pad 2 are formed on the element substrate 3 on which the element function unit 1 is formed by sputtering. Next, an opening is provided in the element substrate 3 by the RIE method from the surface opposite to the element function part 1, and this opening is sealed with a semiconductor substrate 32 (Si substrate) via an epoxy-based die bond material 34. Form.

Next, a dam material is applied in a square shape by screen printing at a position where the dam 8 is formed on the element substrate 3 so as to surround the element function unit 1.
A cap 9 (having a thickness of about 100 μm) made of a Si substrate is brought into contact with the dam 8 and temporarily attached thereto.

  As shown in FIG. 4A, metal bumps 33 are formed on the electrode pads 2 (Au film) on the element substrate 3. Specifically, the solder metal bumps 33 are mounted on the electrode pads 2 using a flux. At this time, the adhesiveness between the metal bump 33 and the electrode pad 2 can be improved by heating the vicinity of the electrode pad 2. The height of the metal bump 33 is preferably about 100 to 150 μm.

  On the other hand, on the circuit board 5 made of a copper-clad laminate (copper foil 0.028 mm) on which a wiring pattern is formed, an electrode film 35 is formed by laminating a Ni film and an Au film by metal plating. Next, a through hole is formed and a conductor is provided through a predetermined position where the electrode pad 35 is formed. On the back surface of the circuit board 5, an external electrode 12 connected to the conductor and formed in the same manner as the electrode pad 35 is provided.

  Subsequently, as shown in FIG. 4B, the element substrate 3 and the circuit substrate 5 are temporarily disposed by being opposed to each other through the metal bumps 33. That is, the electrode pad 2 on the element substrate 3 connected to the element function unit 1 via the wiring and the electrode pad 35 on the circuit board 5 are brought into contact with each other through the metal bump 33.

  After that, the composite composed of the element substrate 3 and the circuit substrate 5 is heated while applying pressure to melt the metal bumps 33 to bond the element substrate 3 and the circuit substrate 5 together. The heating of the composite may be performed while applying an appropriate pressurizing force using a press facility, or may be performed using a constant temperature furnace, a hot plate or the like while applying pressure with a weight or the like as necessary. Good. In this way, the metal bumps 33 between the element substrate 3 and the circuit board 5 are heated and melted, and the element substrate 3 and the circuit board 5 are firmly connected. When the metal bump 33 is formed on the electrode pad 2, even if there is a local variation such as displacement or thickness, the self-alignment function that makes the metal bump 33 spherical by the surface tension when the metal bump 33 melts is appropriately used. It can be deformed to any shape (height).

  After the circuit board 5 and the element board 3 are joined, the back surface of the circuit board 5 on which the external electrodes 12 are formed is exposed using a thermosetting resin for the composite body including the element board 3 and the circuit board 5. Then, the resin sealing is performed to form the electronic component device shown in FIG. In addition, although the manufacturing method of each electronic component apparatus was shown here, when mass-producing the electronic component apparatus of this invention efficiently, it cut | disconnects at a predetermined location with a dicing apparatus from on sealing resin, and is a piece. The electronic component device having the structure of FIG. 1 is formed.

  According to the electronic component device having such a sealing structure, the upper and lower sides of the element function unit 1 are protected by the predetermined space, and the operation characteristics thereof are not impaired. That is, since the dam 8 is formed so as to surround the element function part 1, the sealing resin 11 does not cover the element function part 1.

  Furthermore, by forming the gap 10 necessary for the operating characteristics of the element function unit 1 with the height-adjustable dam 8 having a spacer, the size reduction in the direction perpendicular to the cap 9 can be realized.

  According to the electronic component device of the present invention, it has been possible to reduce the size and thickness to 2 × 1.5 × 0.5 mm.

  In the manufacturing method according to the first and second embodiments of the present invention, the dam 8 is formed on the element substrate 3 having the element function unit 1, but the dam 8 may be formed on the cap 9.

  As described above, the case where the FBAR filter is applied to the element function unit 1 has been described. However, it is also possible to apply a SAW filter that requires the air gap 10 above the FBAR filter.

FIG. 1 is a cross-sectional view showing an electronic component device according to a first embodiment of the present invention. It is sectional drawing which shows the modification of the electronic component apparatus shown in FIG. It is sectional drawing which shows typically the structure of the electronic component apparatus by the 2nd Embodiment of this invention. 4A to 4C are main process cross-sectional views illustrating a method of manufacturing the electronic component device shown in FIG. FIG. 5 is a cross-sectional view showing a conventional electronic component device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Element functional part, 2 ... Electrode pad, 3 ... Element board | substrate, 4 ... Hollow part, 5 ... Circuit board, 6 ... Die-bonding material, 7 ... Bonding wire, 8 ... Dam, 9 ... Cap, 10 ... Air gap, 11 ... Sealing resin, 12 ... external electrode, 13 ... wire pad, 21 ... dam, 22 ... semiconductor substrate, 23 ... hollow part, 31 ... hollow part, 32 ... semiconductor substrate, 33 ... metal bump, 34 ... die bond material, 35 ... Electrode pad, 51 ... Package, 52 ... SAW chip, 53 ... Die bond material, 54 ... Electrode pad, 55 ... Wire pad, 56 ... Bonding wire, 57 ... Cap

Claims (5)

An element substrate having an element function part;
A dam formed so as to surround the element function part;
A cap joined to the dam and forming a void inside thereof;
A circuit board on which the element substrate is mounted and electrically connected to the element substrate;
An electronic component device comprising: a sealing resin for sealing the element substrate.   The electronic component device according to claim 1, wherein the element substrate and the circuit substrate are electrically connected via a bonding wire.   The electronic component device according to claim 1, wherein the element substrate and the circuit substrate are electrically connected via metal bumps.   The electronic component device according to claim 1, wherein the dam has a spacer having an average particle diameter of 2 to 30 μm.   5. The electronic component device according to claim 1, wherein the element substrate has a cavity structure, and a hollow part is provided on a back side of the element function part. 6.

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