JP2015130601A - module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a module capable of obtaining a small acoustic wave device having good electric characteristics.SOLUTION: A module 100 includes: a module substrate 10; and an acoustic wave device 200 buried in the module substrate 10 and including a SAW chip 22 which is mounted on an upper surface of a package substrate 20, a metal sealing part 44 which is provided on the package substrate 20 and seals the SAW chip 22, and a ground terminal 36b which is provided on a lower surface of the package substrate 20 and is electrically connected with the SAW chip 22. The ground terminal 36b and the sealing part 44 are electrically connected with ground through via wiring 16 provided on the module substrate 10 and are not electrically connected with each other in the acoustic wave device 200.

Description

  The present invention relates to a module, for example, a module in which an acoustic wave device is embedded in a module substrate.

  In response to the demand for downsizing of acoustic wave devices, a structure in which an acoustic wave chip is mounted on a package substrate and then the acoustic wave chip is sealed by a sealing portion has been proposed. Moreover, in order to ensure high airtightness, using metal, such as a solder, for a sealing part is proposed (for example, refer patent document 1).

JP 2006-203149 A

  When the acoustic wave chip is sealed by the metal sealing part, if the sealing part is not electrically connected to the ground, the patterns formed on the acoustic wave chip and the package substrate pass through the sealing part. Capacitive coupling causes electrical characteristics to deteriorate. As a method for electrically connecting the sealing portion to the ground, for example, a via wiring is provided on the package substrate, and the sealing portion is electrically connected to the ground terminal of the acoustic wave device via the via wiring. However, in this case, the package substrate is enlarged in order to secure a region for providing the via wiring, and as a result, the acoustic wave device is enlarged. In addition, since the ground terminal of the acoustic wave device and the sealing portion are electrically connected by via wiring penetrating the package substrate, for example, the wiring pattern connected to the signal of the acoustic wave chip and the sealing portion are capacitively coupled. In this case, the electrical characteristics are deteriorated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a module capable of obtaining an elastic wave device that is small and has good electrical characteristics.

  The present invention provides a module substrate, an acoustic wave chip embedded in the module substrate and mounted on an upper surface of the package substrate, and a metal seal provided on the package substrate and sealing the acoustic wave chip. An elastic wave device including a stop portion and a ground terminal provided on a lower surface of the package substrate and electrically connected to the elastic wave chip, and the ground terminal and the sealing portion include: The module is electrically connected to the ground via wiring provided on the module substrate, and is not electrically connected to each other in the acoustic wave device. According to the present invention, it is possible to obtain an elastic wave device that is small and has good electrical characteristics.

  In the above configuration, the package substrate may be a single layer substrate.

  In the above configuration, the sealing portion is configured to be electrically connected to the ground via the wiring provided on the module substrate on the side opposite to the package substrate with respect to the acoustic wave chip. it can.

  The said structure WHEREIN: The said sealing part can be set as the structure electrically connected to a ground through the said some wiring.

  The said structure WHEREIN: The said sealing part can be set as the structure containing the solder sealing part provided surrounding the said acoustic wave chip | tip, and the metal lid provided on the said acoustic wave chip | tip.

  In the above configuration, the acoustic wave chip may include a surface acoustic wave chip or a piezoelectric thin film resonator chip.

  According to the present invention, it is possible to obtain an elastic wave device that is small and has good electrical characteristics.

FIG. 1A is a cross-sectional view illustrating an acoustic wave device according to Comparative Example 1, and FIG. 1B is a top view of the package substrate. 2A is a cross-sectional view showing an acoustic wave device according to Comparative Example 2, and FIG. 2B is a top view of the package substrate. FIG. 3 is a cross-sectional view illustrating the module according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the acoustic wave device built in the module according to the first embodiment. 5A is a top view of the package substrate, FIG. 5B is a cross-sectional view of the package substrate, and FIG. 5C is a bottom view of the package substrate. FIG. 6 is a top view showing the wafer before mounting the acoustic wave chip. FIG. 7 is a cross-sectional view showing a piezoelectric thin film resonator chip.

  First, an acoustic wave device according to a comparative example will be described. FIG. 1A is a cross-sectional view illustrating an acoustic wave device according to Comparative Example 1, and FIG. 1B is a top view of the package substrate. Note that FIG. 1A shows a cross section of a portion corresponding to A-A in FIG. As shown in FIGS. 1A and 1B, a connection terminal 76 and a metal seal ring 86 are provided on the upper surface of the package substrate 70. An acoustic wave chip 72 is flip-chip mounted on the connection terminal 76 by a bump 74. The seal ring 86 is provided so as to surround the acoustic wave chip 72. A metal sealing portion 92 including a solder sealing portion 88 bonded to the upper surface of the seal ring 86 and bonded to the side surface of the elastic wave chip 72, and a metal lid 90 provided on the elastic wave chip 72. The elastic wave chip 72 is sealed. A metal film 94 is provided so as to cover the sealing portion 92.

  On the lower surface of the package substrate 70, a signal terminal 78 and a ground terminal 80 are provided as external terminals of the acoustic wave device. The connection terminal 76, the signal terminal 78, and the ground terminal 80 are electrically connected by a via wiring 82 that penetrates the package substrate 70. That is, the acoustic wave chip 72 is electrically connected to the signal terminal 78 and the ground terminal 80. The sealing portion 92 is also electrically connected to the ground terminal 80 via a via wiring 84 that penetrates the package substrate 70.

  According to the comparative example 1, in order to electrically connect the sealing portion 92 to the ground, the via wiring 84 is provided in the package substrate 70, and the sealing portion 92 is electrically connected to the ground terminal 80 via the via wiring 84. Is connected. In this case, the width of the seal ring 86 is increased in order to secure a region where the via wiring 84 is provided, and the package substrate 70 is increased in size, and as a result, the elastic wave device is increased in size. In addition, since the ground terminal 80 and the sealing portion 92 are electrically connected via the via wiring 84 in the acoustic wave device, for example, a pattern such as a pattern in which the sealing portion 92 is connected to the signal of the acoustic wave chip 72. When this pattern is capacitively coupled, the high frequency electrical characteristics are deteriorated. Further, for example, when the package substrate 70 is a single-layer substrate, the sealing portion 92 is electrically connected to the ground terminal 80 via the via wiring 84 only where the ground terminal 80 is directly under the seal ring 86. There is a restriction that it cannot be done. For this reason, there is a possibility that the ground of the sealing portion 92 is not sufficiently strengthened.

  2A is a cross-sectional view showing an acoustic wave device according to Comparative Example 2, and FIG. 2B is a top view of the package substrate. FIG. 2A shows a cross section of a portion corresponding to A-A in FIG. In Comparative Example 1, the region where the via wiring 84 is provided is secured by expanding the seal ring 86 outward, but in Comparative Example 2, the seal ring 86 is expanded inward as shown in FIG. An area for providing the via wiring 84 is secured. Thereby, it can suppress that the package substrate 70 enlarges. However, as shown in FIG. 2A, the seal ring 86 extends between the upper surface of the package substrate 70 and the acoustic wave chip 72, and the solder sealing portion 88 constituting the sealing portion 92 is provided in the package. It enters between the upper surface of the substrate 70 and the elastic wave chip 72. This is because the solder sealing portion 88 is formed by spreading solder on the seal ring 86. As a result, the solder tends to adhere to the pattern formed on the acoustic wave chip 72, and the electrical characteristics are deteriorated. Also in Comparative Example 2, the high-frequency electrical characteristics deteriorate due to capacitive coupling as described in Comparative Example 1.

  Therefore, an embodiment of a module capable of obtaining an elastic wave device that is small and has good electrical characteristics will be described below.

  FIG. 3 is a cross-sectional view illustrating the module according to the first embodiment. As illustrated in FIG. 3, the module 100 according to the first embodiment includes the acoustic wave device 200 embedded in the module substrate 10. The elastic wave device 200 is a device that processes a high-frequency signal, for example. The module substrate 10 is a multilayer wiring substrate in which a plurality of insulating layers 12 and wiring layers 14 are stacked. The plurality of laminated wiring layers 14 are electrically connected to each other by via wirings 16 penetrating the insulating layer 12. The wiring layer 14 and the via wiring 16 are made of a metal such as copper, for example. The insulating layer 12 is formed of, for example, an epoxy resin, a polyimide resin, or a thermoplastic liquid crystal polymer sheet.

  Here, the acoustic wave device 200 housed and incorporated in the module 100 will be described. FIG. 4 is a cross-sectional view illustrating the acoustic wave device built in the module according to the first embodiment. As shown in FIG. 4, in the acoustic wave device 200, a surface acoustic wave (SAW) chip 22 is flipped by a bump 24 on a flat upper surface of a package substrate 20 made of an insulator such as ceramic, sapphire, or aluminum nitride. Chip mounted. The SAW chip 22 includes a piezoelectric substrate 26 and an IDT (Interdigital Transducer) 28 provided on the surface of the piezoelectric substrate 26 facing the package substrate 20. The piezoelectric substrate 26 is made of a piezoelectric material such as lithium tantalate or lithium niobate. The IDT 28 is made of a metal such as copper or aluminum, for example. The bump 24 is made of metal such as copper, gold, or solder. A gap 30 is formed between the upper surface of the package substrate 20 and the SAW chip 22, and the IDT 28 is exposed to the gap 30 so that vibration is not suppressed. The bump 24 is also exposed in the gap 30.

  Here, the package substrate 20 will be described. 5A is a top view of the package substrate, FIG. 5B is a cross-sectional view of the package substrate, and FIG. 5C is a bottom view of the package substrate. FIG. 5B is a cross-sectional view taken along the line AA in FIGS. 5A and 5C. As shown in FIGS. 5A to 5C, the connection terminal 32 and the seal ring 34 are provided on the upper surface of the package substrate 20. As a member of the package substrate 20, for example, ceramic, sapphire, or the like can be used. The seal ring 34 is provided along the outer periphery of the outer peripheral portion in the upper surface of the package substrate 20. The connection terminal 32 is provided inside the seal ring 34. The connection terminal 32 and the seal ring 34 are made of a metal such as copper, for example.

  External terminals 36 that are external connection terminals of the acoustic wave device 200 are provided on the lower surface of the package substrate 20. The external terminal 36 includes a signal terminal and a ground terminal. The external terminal 36 is made of a metal such as copper, for example. The connection terminals 32 provided on the upper surface of the package substrate 20 and the external terminals 36 provided on the lower surface are electrically connected via via wirings 38 penetrating the package substrate 20. The via wiring 38 is formed of a metal such as copper, for example. No via wiring is provided below the seal ring 34 provided on the upper surface of the package substrate 20, and the seal ring 34 is not electrically connected to the external terminal 36. The package substrate 20 is made of, for example, a single layer substrate, and no wiring extending in a direction parallel to the upper surface of the package substrate 20 is provided therein.

  As shown in FIG. 4, since the bumps 24 are bonded to the connection terminals 32, the SAW chip 22 is electrically connected to the external terminals 36. The seal ring 34 is provided outside the SAW chip 22 so as to surround the SAW chip 22. A metal sealing portion 44 including a solder sealing portion 40 bonded to the upper surface of the seal ring 34 and bonded to the side surface of the SAW chip 22, and a flat metal lid 42 provided on the SAW chip 22. The SAW chip 22 is sealed. The metal lid 42 is made of a metal such as Kovar, for example. A metal film 46 such as copper is provided so as to cover the sealing portion 44.

  The acoustic wave device 200 can be manufactured using a multi-chamfer structure as shown in FIG. FIG. 6 is a top view showing the wafer before mounting the acoustic wave chip. As shown in FIG. 6, a plurality of patterns 49 including the connection terminals 32 and the seal ring 34 described in FIG. 5A are arranged in an array on the upper surface of the wafer 48. Although not shown, the external terminal 36 described with reference to FIG. 5C is provided on the lower surface of the wafer 48. The connection terminals 32 provided on the upper surface of the wafer 48 and the external terminals 36 provided on the lower surface are electrically connected by via wirings 38 penetrating the wafer 48. The wafer 48 is, for example, sapphire. By using sapphire, it is possible to provide a module substrate including an elastic wave device having excellent temperature characteristics.

  After the SAW chip 22 is flip-chip mounted on each of the plurality of patterns 49, for example, a laminate of a SnAg-based solder sheet and a metal lid 42 superimposed thereon is disposed on the plurality of SAW chips 22, and the laminate is formed. Heat and press from above. As a result, solder is filled in the gaps between the plurality of SAW chips 22. The solder wets and spreads on the seal ring 34 and then solidifies and joins the upper surface of the seal ring 34 and the side surface of the SAW chip 22. Therefore, the seal ring 34 is preferably made of a metal having good wettability with respect to solder. As a result, a solder sealing portion 40 that covers the periphery of the SAW chip 22 is formed. A metal lid 42 is disposed on the plurality of SAW chips 22. Thereby, the plurality of SAW chips 22 are sealed by the sealing portion 44 including the solder sealing portion 40 and the metal lid 42. Thereafter, the wafer 48 is cut by dicing and separated into a plurality of SAW chips 22, and then the metal film 46 is formed, whereby the acoustic wave device 200 is obtained.

  As shown in FIG. 4, in the state of the acoustic wave device 200 alone, the sealing portion 44 and the external terminal 36 are independent from each other. That is, the sealing portion 44 and the external terminal 36 (for example, a ground terminal) are not electrically connected within the acoustic wave device 200.

  As shown in FIG. 3, the external terminal 36 of the acoustic wave device 200 built in the module substrate 10 is electrically connected to the wiring layer 14 and the via wiring 16. At least a part of the wiring layer 14a formed on the upper surface of the module substrate 10 is used as a terminal pad, and an electronic component 18 is mounted on the terminal pad. The electronic component 18 is a chip component such as a resistance element, an inductor, or a capacitor, for example. The electronic component 18 may be an active element such as a power amplifier, an antenna switch, or a high frequency IC. The signal terminal 36 a among the external terminals 36 of the acoustic wave device 200 is electrically connected to the electronic component 18 through the wiring layer 14 and the via wiring 16, for example.

  The acoustic wave device 200 and the electronic component 18 are also electrically connected to the wiring layer 14 b formed on the lower surface of the module substrate 10. The wiring layer 14 b on the lower surface of the module substrate 10 functions as an external connection terminal pad of the module 100. That is, the acoustic wave device 200 and the electronic component 18 are electrically connected to terminals and the like on the motherboard of the electronic device via the wiring layer 14 b on the lower surface of the module substrate 10.

  The ground terminal 36b among the external terminals 36 of the acoustic wave device 200 is electrically connected to the wiring layer 14b functioning as a terminal pad for ground via the wiring layer 14 and the via wiring 16 although not explicitly shown in FIG. It is connected to the. The sealing portion 44 of the acoustic wave device 200 serves as a ground terminal pad via the via wiring 16 provided on the upper surface side of the sealing portion 44 (below the sealing portion 44 on the paper surface of FIG. 3). It is electrically connected to the functioning wiring layer 14b. The wiring layer 14b to which the ground terminal 36b is electrically connected and the wiring layer 14b to which the sealing portion 44 is electrically connected are, for example, separate and independent wiring layers.

  According to the first embodiment, the ground terminal 36 b and the sealing portion 44 of the acoustic wave device 200 are electrically connected to the ground via the via wiring 16 provided on the module substrate 10. Are not electrically connected to each other. Thereby, for example, even when the sealing portion 44 is capacitively coupled to another pattern such as a pattern connected to the signal of the SAW chip 22, good high frequency electrical characteristics can be obtained. Further, since the sealing portion 44 is electrically connected to the ground via the via wiring 16 provided on the module substrate 10, a via for connecting the sealing portion 44 to the ground as in the first comparative example. It is not necessary to provide wiring on the package substrate 20. Therefore, the acoustic wave device 200 can be reduced in size.

  The package substrate 20 may be a multilayer substrate in which wiring extending in a direction parallel to the upper surface of the package substrate 20 is provided. However, in order to reduce the height of the acoustic wave device 200, a single-layer substrate may be used. Some cases are preferred. As shown in FIG. 4, the package substrate 20 is only provided with via wirings 38 for electrically connecting the connection terminals 32 on the upper surface and the external terminals 36 on the lower surface. Can be used.

  As shown in FIG. 3, the sealing portion 44 is preferably electrically connected to the ground via the via wiring 16 provided on the module substrate 10 on the opposite side of the package substrate 20 with respect to the SAW chip 22. Thereby, the via wiring 16 between the sealing part 44 and the wiring layer 14b can be shortened. As shown in FIG. 3, the sealing portion 44 is preferably connected to the ground via the plurality of via wirings 16. Thereby, the gland | grand | ground of the sealing part 44 can be strengthened and the electromagnetic shielding effect by the sealing part 44 is acquired. Further, since the heat conduction paths increase, the heat generated in the SAW chip 22 can be effectively dissipated.

  From the viewpoint of simplifying the manufacturing process of the acoustic wave device 200, the external terminal 36 and the metal film 46 of the acoustic wave device 200 are preferably made of the same metal (for example, copper).

  In the first embodiment, as shown in FIG. 3, the acoustic wave device 200 built in the module 100 has the external terminal 36 disposed on the surface side of the module substrate 10 on which the electronic component 18 is provided and sealed on the opposite surface side. Although the case where the stop part 44 is arrange | positioned was shown as an example, the case where it turned upside down may be sufficient. Further, although the SAW chip 22 is shown as an example of the elastic wave chip provided in the elastic wave device 200, other elastic wave chips may be used, for example, a love wave chip, a boundary acoustic wave chip, a piezoelectric thin film resonator (FBAR). : Film Bulk Acoustic Resonator) chip or the like. The acoustic wave device 200 may be a resonator, a transmission filter, a reception filter, or a duplexer.

  FIG. 7 is a cross-sectional view showing a piezoelectric thin film resonator chip. As shown in FIG. 7, the piezoelectric thin film resonator chip 50 has a lower electrode 54, a piezoelectric film 56 such as an aluminum nitride film, and an upper electrode 58 laminated in this order on a substrate 52 such as silicon. A region where the lower electrode 54 and the upper electrode 58 overlap with each other with the piezoelectric film 56 interposed therebetween is a resonance region 60. In the resonance region 60, an elastic wave (a bulk wave of thickness longitudinal vibration) that is excited in the piezoelectric film 56 and propagates in the vertical direction resonates. A gap 62 is formed in the substrate 52 below the resonance region 60. The gap 62 may be formed through the substrate 52 or may be a recess without penetrating. Further, the gap 62 may be formed between the upper surface of the substrate 52 and the lower electrode 54. Furthermore, instead of the gap 62, an acoustic reflection film that reflects an elastic wave may be formed.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Module board | substrate 12 Insulation layer 14, 14a, 14b Wiring layer 16 Via wiring 20 Package board 22 SAW chip 32 Connection terminal 34 Seal ring 36 External terminal 36a Signal terminal 36b Ground terminal 40 Solder sealing part 42 Metal lid 44 Sealing part 50 Piezoelectric thin film resonator chip 100 module 200 acoustic wave device

Claims (6)

A module board;
An acoustic wave chip embedded in the module substrate and mounted on the upper surface of the package substrate; a metal sealing portion provided on the package substrate for sealing the acoustic wave chip; and the package substrate An elastic wave device including a ground terminal provided on a lower surface and electrically connected to the elastic wave chip;
The module, wherein the ground terminal and the sealing portion are electrically connected to the ground via wiring provided on the module substrate, and are not electrically connected to each other in the acoustic wave device. .   The module according to claim 1, wherein the package substrate is a single layer substrate.   The said sealing part is electrically connected to the ground through the said wiring provided in the said module board on the opposite side to the said package board | substrate with respect to the said acoustic wave chip | tip. 2. The module according to 2.   The module according to any one of claims 1 to 3, wherein the sealing portion is electrically connected to a ground via the plurality of wirings.   The said sealing part contains the solder sealing part provided in the circumference | surroundings of the said acoustic wave chip | tip, and the metal lid provided on the said acoustic wave chip | tip, The Claim 1 to 4 characterized by the above-mentioned. The module as described in any one.   The module according to any one of claims 1 to 5, wherein the acoustic wave chip includes a surface acoustic wave chip or a piezoelectric thin film resonator chip.

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