JP5206377B2 - Electronic component module - Google Patents

Description

  The present invention relates to an electronic component module, and more specifically, an acoustic wave module including an acoustic wave device such as a surface acoustic wave device or a boundary acoustic wave device and another electronic component are mounted on a common substrate and covered with a transfer mold resin. The present invention relates to an electronic component module.

  In recent years, electronic component modules for mobile devices have been reduced in size and height. Among them, an elastic wave device mounted on an electronic component module such as a duplexer can secure a vibration space adjacent to a region where an elastic wave such as a surface acoustic wave or a boundary acoustic wave propagates. Since it is necessary, it has become a bottleneck in reducing the height of electronic component modules.

  For example, in the electronic component module shown in the sectional view of FIG. 10, an IC 135, a resistor 136, an inductor 137, a capacitor 138, and a SAW (surface acoustic wave) device 139 are mounted on the connection electrode 134 of the module substrate 130, and a resin layer 140 is covered and sealed. The SAW device 139 has a structure that locally seals the vibration space 133 around the IDT electrode 132 formed on the piezoelectric substrate 131. (For example, refer to Patent Document 1).

Patent Document 2 proposes a duplexer in which an inductor component is formed in a ceramic substrate that connects a transmission filter and a reception filter.
JP 2002-217673 A JP 11-26623 A

  In the configuration of FIG. 10, when resin is used for the structure that seals the vibration space 133 of the SAW device 139 and the resin layer 140 is collectively formed in the transfer molding process, the structure is arranged so that the vibration space 133 is not crushed. Therefore, it is necessary to take measures such as increasing the thickness of the top plate portion facing the IDT electrode 132 or increasing the support layer around the top plate portion. If an inorganic material such as ceramic is used for the top plate portion, it can be made thinner than a resin material, but it is easily broken by impact, so there is a limit even if it is made thin.

  Further, in order to prevent the high pressure when the resin layer 140 is transfer-molded from directly acting on the top plate portion of the structure that seals the vibration air opening 133, the gap between the structure and the module substrate may be It is effective to prefill with a fill resin. However, this is a cost increase factor, and voids are easily generated, which is not preferable in terms of reliability.

  Further, in the configuration of FIG. 10, the inductor 137 is disposed on the module substrate in parallel with the acoustic wave device 139, which is disadvantageous for downsizing.

  As disclosed in Patent Document 2, it is advantageous for downsizing to incorporate an inductor component into a substrate connecting a transmission filter and a reception filter. However, since a ceramic substrate is used, cracking becomes a problem when it is thinned, so there is a limit to reducing the height.

  In view of such circumstances, the present invention intends to provide an electronic component module that can be reduced in size, reduced in height, and increased in reliability with respect to an electronic component module in which an elastic wave device and other electronic components are simultaneously transfer molded. To do.

  In order to solve the above-described problems, the present invention provides an electronic component module configured as follows.

  The electronic component module includes an elastic wave module, an electronic component, and a module substrate. In the acoustic wave module, (a) a structure that covers the periphery of the acoustic wave element and forms a vibration space is disposed on the main surface of the piezoelectric substrate on which the acoustic wave element including an electrode for exciting the acoustic wave is formed. A plurality of acoustic wave devices; (b) a common substrate on which the plurality of acoustic wave devices are mounted so that the structures face each other; and (c) a coating resin disposed on the common substrate and covering the acoustic wave devices. And have. The electronic component includes at least one of a semiconductor device, a capacitance device, and an inductance device. The module substrate is mounted with the elastic wave module and the electronic component. The transfer mold resin is disposed on the module substrate and covers the acoustic wave module and the electronic component. The coating resin of the acoustic wave module is disposed between the common substrate and the structure of the acoustic wave device. The glass transition temperature of the coating resin is higher than the glass transition temperature of the transfer mold resin.

  When the temperature of the resin exceeds the glass transition temperature, the resin softens rapidly. In the above configuration, since the glass transition temperature of the coating resin disposed between the structure of the acoustic wave device and the common substrate is higher than the glass transition temperature of the transfer mold resin, the transfer resin is formed when the transfer mold resin is formed. Strength can be ensured by the coating resin so that the temperature of the mold resin does not exceed the glass transition temperature of the coating resin.

  Therefore, even if the thickness of the top plate portion facing the acoustic wave element is reduced in the structure forming the vibration space of the acoustic wave device, or the common substrate on which the acoustic wave device is mounted is thinned, the transfer mold Resin can be formed, and the height of the electronic component module can be reduced.

  In addition, since the strength when forming the transfer mold resin with the coating resin can be ensured, when the common substrate is a resin substrate including an inductor, the common substrate, regardless of the restriction of the glass transition temperature of the transfer mold resin, Since a resin having a physical property that is advantageous for forming an inductor such as a low dielectric constant can be selected, the inductor can be reduced in size, and the electronic component module can be reduced in size.

  In addition, since the strength at the time of forming the transfer mold resin with the coating resin can be ensured, when the structure of the elastic wave device is a resin, the structure is not limited by the glass transition temperature of the transfer mold resin. A resin material having physical properties such as low moisture permeability and low outgas which is advantageous for sealing the vibration space can be selected. Therefore, it is possible to form an elastic wave device with good reliability, and as a result, it is possible to increase the reliability of the electronic component module.

  Furthermore, since the elastic wave module can be transfer-molded simultaneously with other electronic components that do not require cavities such as semiconductors and capacitors, the molding cost of the electronic component module can be kept low. In addition, since voids are less likely to occur compared to the case where an underfill is provided between the acoustic wave device and the module substrate, the cost of the electronic component module can be reduced and high reliability can be ensured.

  According to the present invention, an electronic component module in which an acoustic wave device and other electronic components are simultaneously transfer molded can be reduced in size, reduced in height, and improved in reliability.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  <Example 1> The electronic component module 50 of Example 1 of this invention is demonstrated referring FIGS.

  FIG. 1 is a cross-sectional view of the acoustic wave device 10. 2 to 7 are cross-sectional views showing a manufacturing process of the electronic component module 50.

  As illustrated in FIG. 7, the electronic component module 50 according to the first embodiment includes a semiconductor device 42 that is a semiconductor device, a chip coil 44 that is an inductance device, a capacitance device (not illustrated), and an acoustic wave on a module substrate 52. The module 40 is mounted and is entirely covered and sealed with a transfer mold resin 46.

  As shown in FIG. 4, the acoustic wave module 40 includes the transmission acoustic wave device 10 and the reception acoustic wave device 10 k mounted on the common substrate 30, covered with a coating resin 32, and sealed. .

  The basic configurations of the acoustic wave devices 10 and 10k are the same. That is, as shown in FIG. 1, a conductive pattern including an IDT (Inter Digital Transducer) electrode 14 and a pad electrode 15 that are comb-like electrodes for exciting an elastic wave is formed on one main surface 12 b of the piezoelectric substrate 12. Is formed. The IDT electrode 14 is covered with a protective film 16. A support layer 20 is formed around the acoustic wave element including the IDT electrode 14. A cover layer 22 is disposed on the support layer 20 with a space between the support layer 20 and the piezoelectric substrate 12, and the cover layer 22 extends along the piezoelectric substrate 12. The support layer 20 and the cover layer 22 are structures that cover the periphery of the acoustic wave element including the IDT electrode 14 and form the vibration space 13. An elastic wave freely propagates in a portion adjacent to the vibration space 13 on the one main surface 12b of the piezoelectric substrate 12.

  The support layer 20 and the cover layer 22 are formed with via-hole conductors 18 that penetrate the support layer 20 and the cover layer 22. One end of the via-hole conductor 18 is connected to the pad electrode 15, and an under bump metal 23 is formed at the other end. On the under bump metal 23, solder bumps 24 for mounting the acoustic wave device 10 are formed.

  As shown in FIG. 4, the acoustic wave devices 10 and 10 k are mounted on the common substrate 30 so that the vibration spaces 13 and 13 k are disposed between the piezoelectric substrates 12 and 12 k and the common substrate 30. The whole is covered and sealed. Thereby, the elastic wave module 40 is formed. The coating resin 32 is also disposed between the cover layers 22 and 22k of the structure of the acoustic wave devices 10 and 10k and the common substrate 30.

  As shown in FIG. 7, the acoustic wave module 40 is mounted on a module substrate 52 together with other electronic components 42 and 44, and is entirely covered and sealed with a transfer mold resin 46.

  Next, a method for manufacturing the electronic component module 50 will be described with reference to FIGS.

  (1) First, the acoustic wave devices 10 and 10k are manufactured.

The transmitting acoustic wave device 10 shown in FIG. 1 is manufactured as follows. That is, on the one main surface 12 b of the piezoelectric substrate 12, a pattern of an acoustic wave element including the IDT electrode 14, a pad electrode 15, and a two-layer wiring pattern (not shown) connecting the IDT electrode 14 and the pad electrode 15. Z). For the piezoelectric substrate 12, lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ), lithium tetraborate (Li ₂ B ₄ O ₇ ), crystal, or the like is used. As materials for the IDT electrode 14 and the pad electrode 15, metals such as Al, Cu, Pt, Au, Ta, W, Ni, Ti, and alloys thereof are used. Cu / Ti is used as the material of the two-layer wiring pattern.

Next, a SiO ₂ film (thickness 25 nm) is formed as the protective film 16 of the IDT electrode 14. The SiO ₂ film is not formed on the pad electrode 15.

  Next, a support layer 20 and a cover layer 22 that form a structure for locally sealing the vibration space 13 around the IDT electrode 14 are formed. The support layer 20 is coated with photosensitive polyimide (thickness 10 μm) and patterned. At this time, patterning is performed so that the pad electrode 15 is exposed, and a via hole (through hole) is formed in the support layer 20. The cover layer 22 is formed by attaching an epoxy resin film (thickness 10 μm) containing a silica filler on the polyimide support layer 20.

  Next, a via hole (through hole) is formed with a laser at a position corresponding to the via hole of the support layer 20 in the cover layer 22 film, and Cu is filled in the via hole of the support layer 20 and the cover layer 22 by electroplating to form a via hole conductor. 18 is formed.

  Next, after plating Ni serving as the under bump metal 23 on the via-hole conductor 18, Au (thickness 0.1 μm) as a solder wetting ensuring film is plated on the Ni film (thickness 0.3 μm).

  Next, the other main surface 12a of the piezoelectric substrate 12 is ground to reduce the thickness of the piezoelectric substrate 12 to 90 μm.

  Next, solder paste printing is performed, reflowed, and flux cleaning is performed to form solder bumps 24.

  Next, the piezoelectric substrate 12, the support layer 20, and the cover layer 22 are diced into individual pieces, whereby the acoustic wave device 10 for transmission is obtained.

  Similarly, the acoustic wave device 10k for reception is manufactured.

  (2) Next, the acoustic wave devices 10 and 10 k are mounted on the common substrate 30 to produce the acoustic wave module 40.

  That is, as shown in FIG. 2, the transmitting acoustic wave device 10 and the receiving acoustic wave device 10k are transferred to the solder bumps 24 and 24k, mounted on the common substrate 30, and reflowed. Implement by. The height of the solder bumps 24 and 24k after mounting is 20 μm.

  The common substrate 30 is a resin substrate in which an inductance 31 is built. As a resin material of the common substrate 30, for example, polyphenylene ether resin (PPE resin) or low dielectric constant BT resin may be used. The common substrate 30 has a three-layer wiring structure, and the inductance 31 is formed between the resin A layer 30a and the resin B layer 30b, and the entire thickness of the common substrate 30 is 60 μm.

  Next, as illustrated in FIG. 4, a coating resin 32 is formed so as to cover the acoustic wave devices 10 and 10 k mounted on the common substrate 30. The coating resin 32 is also formed between the cover layers 22 and 22k that seal the vibration spaces 13 and 13k of the acoustic wave devices 10 and 10k and the common substrate 30.

  As the coating resin 32, a resin having a glass transition temperature higher than that of a transfer mold resin 46 described later, for example, a polyimide resin having a glass transition temperature (Tg point) of 395 ° C. is used. The coating resin 32 may be a high Tg-PPE resin (Tg point 230 ° C.) or the like. At this time, the coating resin 32 covering the back surfaces 10s and 10t of the acoustic wave devices 10 and 10k is controlled to have a thickness of 1 μm or less, and is heated to 350 ° C. to cure the coating resin 32.

  Since the coating resin 32 surrounding the outside of the acoustic wave devices 10 and 10k does not soften at the temperature at which the transfer mold resin 46 is formed, the support layers 20 and 20k, the cover layers 22 and 22k of the acoustic wave devices 10 and 10k, Each of the resin layers 30a and 30b of the common substrate 30 can be thinned.

  Subsequently, the elastic substrate 40 shown in FIG. 4 is obtained by dicing the common substrate 30 and the coating resin 32.

  The thickness of the elastic wave module 40 can be as low as 1 + 90 + 10 + 10 + 20 + 60 = 191 μm in a state where the inductance is incorporated.

  (3) Next, the electronic component module 50 including the elastic wave module 40 is manufactured.

  That is, as shown in FIG. 5, solder bumps 43, 45, 41 are formed on the module substrate 52, and the elastic wave module 40 is mounted together with the semiconductor device 42, the capacitance device (not shown), and the inductor device 44. The electrical connection between the module substrate 52 and each of the electronic components 42, 44, 40 is obtained by performing reflow and flux cleaning at once.

  Next, as shown in FIG. 6, a transfer mold resin 46 that covers the electronic components 42, 44, 40 is formed. At this time, an epoxy resin having a Tg point of 180 ° C. is used as the transfer mold resin 46, and transfer molding is performed under a temperature condition of 190 ° C. slightly higher than the Tg point of the transfer mold resin 46. Since the resin is significantly softened at the boundary of the Tg point, the temperature condition of the transfer mold is generally set to a temperature slightly higher than the Tg point of the resin used for the transfer mold.

  Next, the module substrate 52 and the transfer mold resin 46 are diced using a blade 60 and divided to obtain the electronic component module 50 shown in FIG.

  The electronic component module 50 manufactured through the above steps can be reduced in height.

  That is, the materials of the transfer mold resin 46 and the coating resin 32 are selected so that the glass transition temperature of the transfer mold resin 46 is lower than the glass transition temperature of the coating resin 32 of the acoustic wave module 40. Then, when forming the transfer mold resin 46, the temperature of the transfer mold resin 46 does not exceed the glass transition temperature of the coating resin 32. When the temperature of the coating resin 32 exceeds the glass transition temperature, the coating resin 32 rapidly softens and the strength and rigidity decrease, but the coating resin 32 does not exceed the glass transition temperature when the transfer mold resin 46 is formed. The coating resin 32 does not soften, and the coating resin 32 can ensure strength and rigidity. Therefore, the transfer mold resin 46 can be formed even if the cover layer 22 that is the structure of the acoustic wave device 10 is thinned, the support layer 20 is thinned, or the common substrate 30 is thinned. Therefore, the electronic component module 50 can be reduced in height.

  Further, when ceramic is used for the common substrate 30s of the acoustic wave module 40s as in the electronic component module 50s of the comparative example 1 shown in FIG. 8, if the ceramic is thinned, cracking becomes a problem. There is a limit to low profile. On the other hand, in the electronic component module 50 of the first embodiment, the common substrate 30 of the elastic wave module 40 can be made thinner, and the height can be reduced as compared with the first comparative example.

  In addition, since the strength and rigidity can be ensured by the coating resin 32 when forming the transfer mold resin 46, the inductance 31 can be formed on the common substrate 30 regardless of restrictions on the glass transition temperature of the transfer mold resin 46. Since an advantageous resin having a low dielectric constant or the like can be selected, the inductance 31 can be reduced in size, and the electronic component module 50 can be reduced in size.

  Further, since the elastic wave devices 10 and 10k can ensure strength and rigidity by the coating resin 32 when forming the transfer mold resin 46, the support layer 20 that forms the structure of the elastic wave devices 10 and 10k, For 20k and cover layers 22 and 22k, resin materials with low physical properties such as low moisture permeability and low outgas, which are advantageous for sealing the vibration spaces 13 and 13k, are selected without being restricted by the glass transition temperature of the transfer mold resin. it can. Therefore, it is possible to form the acoustic wave devices 10 and 10k having good reliability, and as a result, the electronic component module 50 can be highly reliable.

  Furthermore, since the elastic wave module 40 can be transfer-molded simultaneously with other electronic components that do not require a cavity such as the semiconductor device 42 and the chip coil 44, the molding cost of the electronic component module 50 can be kept low.

  Further, the electronic component module 50 is compared with the case where the underfill resin 48 is disposed between the elastic wave module 40t and the module substrate 52t as in the electronic component module 50t of the comparative example 2 shown in the cross-sectional view of FIG. Since voids are unlikely to occur, the cost of the electronic component module 50 and high reliability can be ensured.

  <Summary> An acoustic wave device with a resin-based structure that locally seals the vibration space adjacent to the region where the acoustic wave propagates is mounted on a common substrate of the resin-based substrate that contains the inductor component, and vibration is generated. By placing a material with a Tg point (glass transition point) higher than that of transfer mold resin between the structure that seals the space and the common substrate that contains the inductor component, it is small, low-profile, and highly reliable. In addition, an electronic component module incorporating an acoustic wave device that can be transfer-molded simultaneously with other electronic components that do not require cavities such as semiconductor components can be manufactured.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications.

It is sectional drawing of an elastic wave device. Example 1 It is sectional drawing which shows the manufacturing process of an electronic component. Example 1 It is sectional drawing which shows the manufacturing process of an electronic component. Example 1 It is sectional drawing which shows the manufacturing process of an electronic component. Example 1 It is sectional drawing which shows the manufacturing process of an electronic component. Example 1 It is sectional drawing which shows the manufacturing process of an electronic component. Example 1 It is sectional drawing which shows the manufacturing process of an electronic component. Example 1 It is sectional drawing of an electronic component. (Comparative Example 1) It is sectional drawing of an electronic component. (Comparative Example 2) It is sectional drawing of an electronic component. (Conventional example)

Explanation of symbols

10, 10k elastic wave device 12, 12k piezoelectric substrate 13, 13k vibration space 14 elastic wave excitation electrode (IDT electrode)
18 Via-hole conductor 20, 20k Support layer (structure)
22,22k Cover layer (structure)
30 Common substrate 32 Coating resin 40 Elastic wave module 42 Semiconductor device (semiconductor device)
44 Chip coil (inductance device)
46 Transfer mold resin 50 Electronic component module 52 Module substrate

Claims (1)

A plurality of acoustic wave devices in which a structure that covers a periphery of the acoustic wave element and forms a vibration space is disposed on a principal surface of a piezoelectric substrate on which an acoustic wave element including an electrode for exciting an acoustic wave is formed, and the structure An acoustic wave module having a common substrate on which a plurality of the acoustic wave devices are mounted so that their bodies face each other, and a coating resin disposed on the common substrate and covering the acoustic wave device;
An electronic component including at least one of a semiconductor device, a capacitance device, and an inductance device;
A module substrate on which the acoustic wave module and the electronic component are mounted;
A transfer mold resin disposed on the module substrate and covering the acoustic wave module and the electronic component;
With
The coating resin of the acoustic wave module is disposed between the common substrate and the structure of the acoustic wave device,
The electronic component module, wherein the glass transition temperature of the coating resin is higher than the glass transition temperature of the transfer mold resin.

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