JP2007235303A - Electronic component and manufacturing method therefor, and communications equipment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component, such as, a resin sealed filter and a duplexer which is prevented from undergoing deterioration in modulation distortion characteristics due to disturbance waves. <P>SOLUTION: The electronic component comprises a wiring board 110; a function element 120, mounted on at least one principal face of the wiring board 110; connection members 140 for electrically connecting the function element 120 to the wiring board 110; and resin 130 disposed on the wiring board 110 and for covering the function element 120 and at least a part of the principal face mounted with the function element 120, wherein the resin 130 is provided with a filler made of a magnetic material, so that the magnetic field of the magnetic filler contained in the sealing resin significantly improves the nonlinear distortion level with respect to various disturbance waves. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic component such as a surface acoustic wave device, a piezoelectric bulk wave device, and a mechanical switch, a manufacturing method thereof, and a communication device using the same.

  Components built in portable electronic devices are required to be smaller and lighter while maintaining high performance. For example, a filter or duplexer for selecting a high-frequency signal used in a mobile phone is required to be small and have a small insertion loss. As one of the filters that satisfy these requirements, a surface acoustic wave (SAW) device using piezoelectric vibration and a film bulk acoustic resonator (FBAR) device are known.

  FIG. 8 shows a cross-sectional view of a conventional surface acoustic wave device as an example of an electronic component. Here, 610 is a substrate, 620 is a surface acoustic wave element as a functional element, 630 is a sealing resin, 640 is a conductive bump, 650 is a gap, and 660 is a shield layer. On the substrate 610, a wiring pattern 611, an external terminal 613, and a via hole 612 are formed for electrical connection with the surface acoustic wave element.

  A conventional electronic component will be described in detail following its manufacturing method. First, an electrode thin film formed by a vapor deposition method, a sputtering method, or the like on an interdigital electrode for exciting a surface acoustic wave and an electrode pad for inputting / outputting an external electric signal on a piezoelectric substrate, a photolithography technology The surface acoustic wave element 620 is formed by patterning by the above. Next, the substrate 610 is mounted via the conductive bump 640 so that the functional surface of the elastic surface element 620 is opposed to the substrate 610. As the conductive bump 640, a gold (Au) ball bump, a solder bump, or the like is used. Next, sealing is performed with a resin so that the back surface of the surface acoustic wave element and the periphery thereof are covered so that a gap is held in the functional portion of the surface acoustic wave element 620. As the resin, an epoxy-based thermosetting or thermoplastic resin is widely used, and an inorganic insulating material such as silica (SiO 2) or alumina (Al 2 O 3) is used as a filler (filler). Finally, a shield layer 660 made of metal is formed on the resin surface. By forming the shield layer, a surface acoustic wave device that is resistant to external noise and excellent in moisture resistance can be obtained (see, for example, Patent Document 1).

  On the other hand, FIG. 9 shows a sectional view of a conventional surface acoustic wave device as another example of an electronic component. Here, 710 is a substrate, 720 is a surface acoustic wave element as a functional element, 730 is a sealing resin, 740 is a conductive bump, and 750 is a gap. In the substrate 710, a wiring pattern 711, an external terminal 713, and a via hole 712 are formed for electrical connection with the surface acoustic wave element.

  With the configuration shown in FIG. 9, when the moisture resistance of the surface acoustic wave element is reinforced by a protective film on the element functional surface, a small, low-profile elastic surface is used without using a metal film such as a shield layer. A wave device can be obtained (see, for example, Patent Document 2).

As described above, the surface acoustic wave device can be reduced in size by using the packaging of the surface acoustic wave device which does not require wire bonding without using the conventionally used metal or ceramic multilayer package. , Low profile and high reliability.
JP-A-2005-73219 JP 2006-14099 A

  However, the conventional configuration shown in FIGS. 8 and 9 has a problem that the intermodulation distortion characteristics of the electronic component deteriorate due to the downsizing of the device. Specifically, in a high-frequency filter, duplexer, high-frequency mechanical switch, or the like, there is a problem that intermodulation distortion characteristics deteriorate in a reception band due to a transmission signal and an interference wave coming from the outside such as an antenna.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide an electronic component having good intermodulation distortion characteristics and a manufacturing method thereof without increasing the size of the electronic component. It is another object of the present invention to provide an electronic component that is inexpensive and has good high-frequency characteristics without a shield layer.

  In order to solve the above problems, an electronic component of the present invention includes a wiring board, a functional element mounted on at least one main surface of the wiring board, and a connection for electrically connecting the wiring board and the functional element. An electronic component comprising a member and a resin that covers at least a part of a main surface on which the functional element is mounted on the wiring board and the functional element, wherein the resin is a filler made of a magnetic material It is characterized by containing.

  The method for manufacturing an electronic component of the present invention includes at least a step of mounting a functional element on a wiring board, at least a part of a main surface on the wiring board on which the functional element is mounted, and the functional element. And a step of coating with a resin using a magnetic material as a filler.

  According to the electronic component of the present invention, an electronic component having high reliability and excellent high frequency characteristics such as intermodulation distortion characteristics can be obtained without greatly changing the conventional structure. Further, it is possible to provide an electronic component that is inexpensive and excellent in high-frequency characteristics without forming a shield layer.

  Furthermore, according to the method for manufacturing an electronic component of the present invention, an inexpensive and small-sized electronic component having excellent high frequency characteristics such as intermodulation distortion characteristics can be obtained without adding a new process.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view schematically showing the structure of an electronic component according to Embodiment 1 of the present invention. In FIG. 1, 110 is a wiring board, 111 is a wiring electrode, 112 is a via hole, 113 is an external terminal, 120 is a functional element, 130 is a sealing resin, 140 is a conductive bump, and 150 is a gap.

  In the present embodiment, a surface acoustic wave device using a piezoelectric substrate is used as an electronic component. For the functional element 120, lithium tantalate was used. In addition to lithium tantalate, piezoelectric single crystals such as lithium niobate and potassium niobate can be selected. Alternatively, a substrate in which a piezoelectric thin film such as aluminum nitride (AlN), zinc oxide (ZnO), or lead zirconate titanate (PZT) is formed on a silicon substrate, a sapphire substrate, a glass substrate, or the like may be used.

  On one main surface of the functional element 120, a functional portion 121 made of a comb-shaped electrode for exciting a surface acoustic wave is formed by patterning a conductive thin film such as aluminum using ordinary photolithography. In this embodiment, after forming a functional part on one main surface of the functional element, the other main surface is back-ground by chemical mechanical polishing (CMP), and the thickness of the functional element is about 150 μm.

  In the present embodiment, the resonators 202, 203, and 204, which are formed by comb-shaped electrodes and have different appropriate resonance frequencies, are changed to a ladder type (FIG. 2A) or a lattice type (FIG. 2B). By connecting, a band pass filter can be configured. The circuit configuration of the band pass filter is not limited to the configuration shown in FIG.

  For the wiring substrate 110, alumina having a thickness of about 200 μm was used. On the wiring substrate 110, a pattern electrode 111 for electrical connection with the functional element 120, a terminal electrode 113 for electrical connection with an external circuit, and an electrical connection between the pattern electrode 111 and the terminal electrode 113 are achieved. A via hole 112 is provided. In addition to alumina, a low-temperature fired ceramic substrate containing glass, a resin substrate, a silicon interposer, or the like may be used. The functional element 120 is mounted on the wiring substrate 110 in a face-down manner by conductive bumps 140 which are connection members made of solder bumps, gold bumps, or the like.

  Finally, a small and low-profile electronic component can be obtained by molding the back surface of the functional element 120 and its periphery with the sealing resin 130. In the present embodiment, an epoxy thermosetting resin using a magnetic material as a filler is used as the resin material. As the magnetic filler, it is preferable to use spray powder such as iron (Fe), permalloy (Fe—Ni), MnZn ferrite, and chromium oxide. In addition, an organic material carrying a magnetic metal or the like may be used, and an electronic component having high affinity with the base epoxy resin and high reliability can be obtained.

  In addition, when the magnetic material is conductive iron powder or the like and the filler content is high and there is a possibility that the plurality of wiring patterns 111 may be electrically short-circuited, the surface thereof is oxidized by the magnetic material itself. It is preferable to coat with an inorganic insulating material such as a film or silicon oxide.

  FIG. 3 is a cross-sectional view schematically showing the structure of a duplexer including two filters having different pass frequency bands. In FIG. 3, reference numeral 110 denotes a wiring board, 120a denotes a transmission filter, 120b denotes a reception filter, and 160 denotes a transfer circuit (line) formed by an inner layer electrode of the wiring board 110. FIG. 4 is a block diagram of the duplexer, which includes transmission / reception terminals 301 and 302, an antenna terminal 303, transmission / reception filters 304 and 306, and a phase shift circuit 305.

  In the case of configuring a duplexer, a plurality of different surface acoustic wave devices shown in FIG. 1 may be connected on another substrate such as a mother substrate, but it is better to mount on the same wiring substrate 110. preferable. Thereby, a smaller electronic component can be obtained.

  Next, intermodulation distortion characteristics when this duplexer is used will be described.

  FIG. 5 is a block diagram simply showing a wireless unit of a wireless communication device that performs simultaneous transmission and reception such as a mobile phone. In FIG. 5, 501 is a transmission terminal, 502 is a reception terminal, 503 is a baseband (BB) unit, 504 is a power amplifier (PA), 507 is a duplexer comprising a transmission filter 505 and a reception filter 506, and 508 is a low noise amplifier. (LNA) and 509 are antennas.

  A signal input from the transmission terminal 501 is modulated by the baseband unit 503, and the signal is amplified by the power amplifier 504. Then, the signal is filtered through the transmission filter 505, and a signal in the transmission band is transmitted from the antenna 509. At this time, the duplexer is designed so that the transmission signal does not enter the reception filter 506. The signal received from the antenna 509 is filtered through the reception filter 506 without going around the transmission filter, amplified by the LNA 508, demodulated by the baseband 503, and transmitted to the reception terminal 502.

  In a situation where a plurality of channels and systems using various radio frequencies are mixed, signals (interfering waves) having a plurality of frequency components are received from the antenna 509. For example, the transmission signal of the own terminal and the interference wave signal from the antenna are distorted due to nonlinearity of each component such as a duplexer, and when this signal enters the reception band, a failure such as a deterioration in reception level occurs. For example, when signals having different frequencies of fa and fb are input, second harmonics faX2 and fbX2 are generated due to nonlinearity of electronic components. A signal such as (2fa-fb) or (2fb-fa) is generated as the third-order intermodulation distortion (IM3) by the harmonics and the fundamental waves f1 and f2.

  Conventionally, it is a signal at a level that has not been a problem with duplexers using metallic packages or large ceramic packages, etc., but electronic components are rapidly becoming smaller, such as moisture resistance of functional elements themselves Due to the improved reliability, when a resin-molded duplexer is used, it becomes a level that cannot be ignored, which is a cause of deterioration of the call quality of the radio.

  FIG. 6 shows an example of a measurement system for intermodulation distortion characteristics. In FIG. 6, 401 is a signal generator (SG), 402 is a power amplifier (PA), 407 is a duplexer comprising a transmission filter 405 and a reception filter 406, and 409 is a spectrum analyzer (SA).

  In this embodiment, assuming a North American PCS system, a transmission filter having a transmission band of 1850 MHz and 1910 MHz from a signal generator 401 and having a passband of a power amplifier 402, an isolator 403, and 1850 to 1910 MHz is provided. After that, the antenna end of the duplexer 407 was controlled to be 20 dBm.

  Next, as a disturbing wave, when the transmission frequency is Tx and the reception frequency is Rx from the signal generator 411, (Rx−Tx) = 80 MHz, (Rx + Tx) = 1770 MHz to 1830 MHz, (2Tx−Rx) = 3780 MHz. A frequency of ˜3900 MHz and (2Tx + Rx) = 5630 MHz to 5810 MHz was generated. The signal generated here passed through a reception filter 406 having a passband of 1930 to 1990 MHz, and a distortion level was measured by a spectrum analyzer 409. The signal level of the interference wave was 0 to 5 dBm, the reception level was measured, the distortion at the time of -15 dBm input was obtained from the exterior, and the conventional electronic component and the electronic component of the present invention were compared.

  First, when the interference wave is (Rx-Tx), in the case of the conventional duplexer, when the transmission signal is 1850 MHz to 1910 MHz, the distortion is about -70 dBm to -90 dBm, but the structure of the present invention. When the duplexer was used, it was confirmed that the distortion was −120 dBm or less over the entire band, which was greatly improved.

  When the interference wave is (Rx + Tx), it is about −90 dBm in the conventional configuration, whereas it is −110 dBm or less in the configuration of the present invention. Similarly, when the interference wave is (2Tx−Rx), the conventional configuration is −80 to −90 dBm, and the configuration of the present invention is −110 dBm or less. Further, when the interference wave is (2Tx + Rx), the conventional configuration is approximately −110 dBm, whereas the configuration of the present invention can ensure −120 dBm or less.

  As described above, the non-linear distortion level can be significantly improved with respect to various interference waves by the magnetic field of the magnetic filler contained in the sealing resin, and an electronic component having excellent electrical characteristics can be obtained. . In addition, by using the electronic component of the present invention, a communication device excellent in call quality can be realized.

  The measurement of intermodulation distortion is not limited to the measurement system used in the present invention. In addition, it is preferable to use an isolator or a band pass filter as necessary to protect the measurement system. Moreover, although the effect of implementation on the duplexer has been described, in the case of measurement of a bandpass filter, the same evaluation can be performed by inputting two signal waves and an interference wave from the input terminal.

  The electronic component of the present invention does not change the size of the electronic component having the conventional structure, and can improve the electrical characteristics without impairing the same small electronic component as the conventional one. Further, it is possible to obtain an electronic component that is inexpensive and excellent in electrical characteristics without requiring a shield layer forming step.

  In the present embodiment, a surface acoustic wave device is used as an electronic component, but the same effect can be obtained with other high-frequency filters such as a thin film bulk wave resonator (FBAR) device using a piezoelectric thin film. In the present embodiment, the duplexer has been described. Needless to say, the same effect can be obtained with a single filter.

  In this embodiment, the case where the functional element is mounted by the face-down method has been described. However, when the functional unit is directly resin-molded, or when the functional unit has a separate space holding structure. The same effect can be obtained even when electrical connection is performed by wire bonding or the like after the functional element is bonded and fixed to the wiring board.

  Further, as shown in FIG. 7, the same effect can be obtained in a mechanical switch such as a MEMS (Micro Electro-Mechanical System) used in a similar wireless circuit.

  In FIG. 7, 501 is a transmission terminal, 502 is a reception terminal, 503 is a baseband (BB) unit, 504 is a power amplifier (PA), 505 is a transmission filter, 506 is a reception filter, 508 is a low noise amplifier (LNA), 509 Is an antenna, 511 is a high-frequency switch for switching between transmission and reception.

  At the time of transmission, the signal input from the transmission terminal 501 is modulated by the baseband unit 503, and the signal is amplified by the power amplifier 504. Then, the signal is filtered through the transmission filter 505, and a signal in the transmission band is transmitted from the antenna 509. At the time of reception, a signal received from the antenna 509 is filtered through the reception filter 506 without going around the transmission filter, amplified by the LNA 508, demodulated by the baseband 503, and transmitted to the reception terminal 502. As described above, the switch is used when transmission and reception are performed in a time division manner, and a mechanical switch using the MEMS technology can be used.

  Even in such a system, as in the case of the duplexer, when a mechanical switch is formed on a silicon substrate and sealed with a sealing resin that uses a magnetic material as a filler, the magnetic material filler is not included. In comparison, it was possible to obtain an improvement effect of 10 to 40 dBm against various interference waves.

  As described above, a wiring board, a functional element mounted on at least one main surface of the wiring board, a connection member that electrically connects the wiring board and the functional element, and the wiring board In an electronic component composed of at least a part of a main surface on which the functional element is mounted and a resin that covers the functional element, the resin contains a filler composed of a magnetic material, thereby causing intermodulation distortion. A small electronic component having excellent high frequency characteristics can be obtained.

  In addition, when the filler is a conductive material, the magnetic material is coated without covering between wiring patterns even when the filler content is high by covering the filler with an insulating material. There is no deterioration of the magnetic properties of the filler, and there can be obtained a highly reliable electronic component that does not change with time.

  In addition, since the filler is an organic material supporting a magnetic metal such as iron (Fe), it has high affinity with a resin such as an epoxy resin that is a general base material of a sealing material, and has long-term reliability. An electronic component having excellent properties can be obtained.

  Furthermore, in order to obtain the electronic component, a step of mounting a functional element on a wiring board, at least a part of a main surface on the wiring board on which the functional element is mounted, and the functional element By providing at least a step of coating with a resin whose material is a filler, it is possible to provide a method for manufacturing an electronic component having excellent high-frequency characteristics and reliability.

  Further, a communication device including an antenna, a transmission circuit and a reception circuit, wherein the electronic parts such as a bandpass filter, a duplexer, and a switch are connected to the antenna and the transmission circuit or the reception circuit, or By providing at least one of the transmission circuit and the reception circuit, a communication device having good intermodulation distortion characteristics and excellent call quality can be obtained.

  The electronic component according to the present invention can be realized inexpensively by a simplified process without affecting the small and low profile, and has excellent high frequency characteristics such as intermodulation distortion, out-of-band attenuation, and isolation. Furthermore, it is possible to provide an electronic component with excellent reliability.

  By using the electronic components, it is possible to realize a low-loss and small piezoelectric vibration device and functional devices such as a filter, a duplexer, an actuator, and a mechanical switch. A wireless communication device that is strong and excellent in call quality can be provided.

Sectional schematic diagram which shows the structure of the electronic component in Embodiment 1 of this invention The block diagram which shows the structure of the filter in Embodiment 1 of this invention. Sectional schematic diagram which shows the structure of the duplexer in Embodiment 1 of this invention. The block diagram which shows the structure of the duplexer in Embodiment 1 of this invention. The block diagram of the communication apparatus in Embodiment 1 of this invention The block diagram which shows the measurement system in Embodiment 1 of this invention The block diagram of the communication apparatus in Embodiment 1 of this invention Cross-sectional schematic diagram showing the structure of a conventional electronic component Cross-sectional schematic diagram showing the structure of another conventional electronic component

Explanation of symbols

DESCRIPTION OF SYMBOLS 110 Wiring board 111 Wiring pattern 112 Via hole 113 External terminal 120 Functional element 130 Sealing resin 140 Conductive bump 150 Space | gap 201 Input / output terminal 202 Series resonator 203 Parallel resonator 204 Bypass resonator 205 Inductor 301,501 Transmission terminal 302,502 Reception terminal 303 Antenna terminal 304, 405, 505 Transmission filter 305 Phase shift circuit 306, 406, 506 Reception filter 307, 407, 507 Duplexer 401, 411 Signal generator 402, 504 Power amplifier 409 Spectrum analyzer 503 Baseband unit 508 LNA
509 Antenna 510 Communication device 511 Switch

Claims (8)

A wiring board; a functional element mounted on at least one main surface of the wiring board; a connection member for electrically connecting the wiring board and the functional element; and the functional element mounted on the wiring board. An electronic component comprising a resin that covers at least a portion of the principal surface and the functional element, wherein the resin contains a filler made of a magnetic material. The electronic component according to claim 1, wherein the filler is a magnetic material coated with an insulating material. The electronic component according to claim 1, wherein the filler is an organic material carrying a magnetic material. The electronic component according to claim 1, wherein the magnetic material includes at least an element selected from nickel (Ni), iron (Fe), chromium (Cr), cobalt (Co), and manganese (Mn). The electronic component according to claim 1, wherein the functional element is a passive component. The electronic component according to claim 1, wherein the functional element is a filter or a mechanical switch using elastic vibration. A step of mounting a functional element on the wiring board; and covering at least a part of the main surface of the wiring board on which the functional element is mounted and the functional element with a resin having a magnetic material as a filler. An electronic component manufacturing method comprising at least a process. A communication device including an antenna, a transmission circuit, and a reception circuit, wherein the electronic component according to any one of claims 1 to 6 is connected to the antenna and the transmission circuit or the reception circuit, or A communication device provided in at least one of the transmission circuit and the reception circuit.

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