JP2011100649A - Substrate with built-in electronic component and electronic module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that initial characteristics of an electronic module are deviated to have an ESD protection effect faded, as an ESD protection component is mounted on a substrate of the electronic module. <P>SOLUTION: The substrate with a built-in electronic component 1, in addition to at least one electronic component element built in, has an ESD protection element fitted, which 2 is structured of a cavity part formed inside the substrate with a built-in electronic component, and a pair of discharge electrodes formed in opposition in the cavity part; and the ESD protection element 2 is to be integrally formed with the electronic component element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  Electronic components with precise structures such as IC elements and SAW elements are mounted, and in electronic modules that function with high accuracy, ESD (Electro-Static Discharge) measures are taken to prevent charged objects from touching. Even when they are close to each other, it is an important issue to prevent the mounted electronic component element or the electronic module itself from being damaged or malfunctioning.

  Conventionally, in an electronic module, as an ESD countermeasure, for example, an ESD protection component as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2001-43954) is mounted on a substrate.

  For example, as shown in FIG. 11, the ESD protection component includes a pair of discharge electrodes 103 a and 103 b facing each other inside a cavity 102 formed in an insulating element body 101, and both ends of the element body 101. In this structure, external electrodes 104a and 104b are formed. By mounting this ESD protection component on the substrate of the electronic module and inserting it between the signal line and the ground electrode, even if an excessive voltage due to static electricity is applied to the signal line or the like, Is discharged in the ESD protection component and led to the ground side, thereby preventing the electronic component elements such as the IC element and the SAW element from being damaged or malfunctioning.

JP 2001-43954 A

  However, in the above-described method for mounting the ESD protection component on the substrate of the electronic module, by mounting the ESD protection element, stray inductance is generated between the ESD protection component and the electronic component element connected thereto. Therefore, there is a problem that the initial characteristics of the electronic module are shifted due to the influence of the stray inductance. Further, when variations occur in the mounting state of the ESD protection component, there is a problem that characteristics vary between individual electronic modules.

  In addition, since a floating inductance is generated between the ESD protection component and the ground electrode formed on the substrate, static electricity is less likely to be discharged to the ground electrode side in the ESD protection component, and the ESD protection effect is reduced. there were.

  Further, in addition to electronic component elements such as IC elements on the surface of the substrate, an ESD protection component must be mounted, and a substrate with a large surface area must be used, so that the electronic module itself is enlarged. there were.

  Further, since another ESD protection component is used, there is a problem that the cost is increased.

  The present invention has been made to solve the above-described problems of the prior art, and as its means, the electronic component built-in substrate of the present invention is an electronic component built-in substrate having at least one electronic component element built therein. An ESD protection element is further provided inside, and the ESD protection element is composed of at least a cavity formed inside the electronic component built-in substrate and a pair of discharge electrodes formed to face each other in the cavity. In addition, the ESD protection element is formed integrally with the electronic component element.

  The electronic module of the present invention is configured by further mounting electronic component elements on the surface of the electronic component built-in substrate of the present invention described above.

  In the component-embedded substrate or electronic module of the present invention, the electronic component element incorporated in the interior and the ESD protection element incorporated in the interior are integrally formed, so that the ESD protection element is mounted later. By mounting the ESD protection element as in the conventional method, the characteristics of the electronic module are not shifted. Further, there is no problem that the characteristics vary among individual electronic modules depending on the mounting state of the ESD protection element.

  Further, unlike the prior art, it is not necessary to mount an ESD protection component in addition to the electronic component element on the surface of the substrate, so that the component-embedded substrate or the electronic module can be downsized.

  Furthermore, since the ESD protection component is not separately used, the cost can be reduced.

It is a fragmentary sectional view which shows the electronic module using the electronic component built-in board | substrate concerning embodiment of this invention. 2A and 2B show an ESD protection element and a capacitor element built in the electronic component built-in substrate according to the embodiment of the present invention shown in FIG. 1, FIG. 2A is an equivalent circuit diagram, and FIG. 2B and FIG. It is sectional drawing. Note that FIG. 2C illustrates a cross section of a portion XX in FIG. FIG. 3A is an equivalent circuit diagram, and FIGS. 3B and 3C are partial views showing an ESD protection element and an inductor element built in an electronic component built-in substrate according to a modification of the embodiment of the present invention. It is sectional drawing. Note that FIG. 3C illustrates a cross section of the YY portion in FIG. 4A shows an ESD protection element, a capacitor element, and an inductor element built in an electronic component built-in board according to a modification of the embodiment of the present invention. FIG. 4A is an equivalent circuit diagram, and FIG. ) Is a partial cross-sectional view. Note that FIG. 4C illustrates a cross section of a ZZ portion in FIG. It is an equivalent circuit diagram which shows the high frequency switch module (electronic module) concerning the application example of this invention. FIG. 6 is a stacking diagram of electronic component built-in substrates used in the high-frequency switch module (electronic module) according to the application example of the present invention shown in FIG. 5. 6A to 6L in FIG. 6 to FIG. 10 constitute one electronic component built-in substrate. FIG. 6 is a stacking diagram of electronic component built-in substrates used in the high-frequency switch module (electronic module) according to the application example of the present invention shown in FIG. 5. FIG. 6 is a stacking diagram of electronic component built-in substrates used in the high-frequency switch module (electronic module) according to the application example of the present invention shown in FIG. 5. FIG. 6 is a stacking diagram of electronic component built-in substrates used in the high-frequency switch module (electronic module) according to the application example of the present invention shown in FIG. 5. FIG. 6 is a stacking diagram of electronic component built-in substrates used in the high-frequency switch module (electronic module) according to the application example of the present invention shown in FIG. 5. It is sectional drawing which shows the conventional ESD protection element.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a partial cross-sectional view showing an electronic module using an electronic component built-in substrate according to an embodiment of the present invention. FIG. 2 shows an ESD protection element and a capacitor element built in the electronic component built-in substrate, FIG. 2 (A) is an equivalent circuit diagram, and FIGS. 2 (B) and 2 (C) are partial sectional views. Note that FIG. 2C shows a portion XX in FIG.

  In FIG. 1, reference numeral 1 denotes an electronic component built-in substrate. An insulating material such as ceramic or resin can be used for the electronic component built-in substrate 1. In the present embodiment, ceramic is used.

  An ESD protection element 2 and a capacitor element 3 are integrally formed inside the electronic component built-in substrate 1. Further, inside the electronic component built-in substrate 1, internal wiring 4, vias 5, internal ground electrodes 6, capacitor elements 7 that are other electronic component elements, and inductor elements 8 are formed.

  An external ground electrode 9 and a terminal electrode 10 are formed on the lower surface of the electronic component built-in substrate 1, and an IC element 11 and a SAW element (SAW duplexer element) 12 are mounted on the upper surface as electronic component elements. ing.

  In the electronic module having such a configuration, a necessary electronic circuit is configured by an electronic component element built in the electronic component built-in substrate 1 and an electronic component element mounted on the surface of the electronic component built-in substrate 1. . The electronic module having such a configuration causes the static electricity to be discharged in the ESD protection element 2 even when an excessive voltage due to static electricity is applied when the charged object is in contact with or in proximity to the ground electrode. The IC element 11, the SAW element 12, and other electronic component elements are not damaged or malfunction.

  Although not shown in FIG. 1, the SAW element 12 is also connected to the ground electrode via the ESD protection element 2. According to the present invention, a necessary number of ESD protection elements 2 can be formed inside the electronic component-embedded substrate 1, and the number of ESD protection components mounted on the substrate can be increased as in the prior art. Since it is not necessary, it greatly contributes to cost reduction. In particular, if a plurality of ESD protection elements 2 are formed in the same layer of the electronic component built-in substrate 1, the number of ESD protection elements 2 can be increased with almost no increase in cost.

  Next, the ESD protection element 2 and the capacitor element 3 formed inside the electronic component built-in substrate 1 will be described in more detail.

  As shown in FIG. 2A, the ESD protection element 2 and the capacitor element 3 are connected in parallel, and one end of each is connected to the ground electrode.

  As shown in FIGS. 2B and 2C, the ESD protection element 2 forms a cavity 13 in the electronic component built-in substrate 1, and an insulating material constituting the electronic component built-in substrate 1 on the bottom surface of the cavity 13. 14a (ceramic in the present embodiment) and a mixed portion 14 made of a mixed material including a metal material 14b is formed, and a pair of discharge electrodes 15a and 15b are formed on the mixed portion 14 so as to face each other. Become.

  In addition, although the mixing part 14 is not necessarily essential for the basic function of the ESD protection element 2, since it has the following advantages by providing, the mixing part 14 is preferable.

  Although the kind of the metal material 14b of the mixing part 14 is not limited, Cu was used in this embodiment. The material of the discharge electrodes 15a and 15b is not limited, but Cu is used in the present embodiment as in the case of the metal material 14b.

  Since the mixing portion 14 is made of a material including the insulating material 14a and the metal material 14b, the thermal expansion coefficient is intermediate between the thermal expansion coefficient of the discharge electrodes 15a and 15b and the thermal expansion coefficient of the electronic component built-in substrate 1. The function of alleviating the difference in coefficient of thermal expansion between the discharge electrodes 15a and 15b and the electronic component built-in substrate 1 is achieved. As a result, heat is generated when the electronic component built-in substrate 1 is formed by baking, when the completed electronic module of the present invention is mounted on the printed circuit board of the electronic device by reflow soldering, or when the electronic device is used. Even if it adds, it is suppressed by the mixing part 14 that the discharge electrodes 15a and 15b peel from the electronic component built-in board | substrate 1. FIG. Therefore, changes in characteristics such as the discharge start voltage over time are also suppressed.

  Moreover, if the kind and quantity of the metal material 14b contained in the mixing part 14 are adjusted, the discharge start voltage can be adjusted. Specifically, the discharge start voltage decreases as the material has higher conductivity or as the amount increases.

  Although not shown, a sealing layer is formed under the mixing portion 14 and on the ceiling portion of the cavity portion 13 to prevent the glass component from penetrating from the electronic component built-in substrate 1 into the ESD protection element 2. May be. That is, when the electronic component built-in substrate 1 is formed of ceramic containing a glass component, the glass component penetrates from the electronic component built-in substrate 1 into the mixing portion 14 and the cavity portion 13 of the ESD protection element 2, and the insulating material 14a and the metal material 14b. However, if a sealing layer is formed under the mixing portion 14 and on the ceiling portion of the cavity portion 13, such a problem can be prevented. . Note that alumina or the like can be used as the material of the seal layer.

  On the other hand, the capacitor element 3 is formed in the electronic component built-in substrate 1 with a pair of capacitor electrodes 16a and 16b arranged to face each other with a predetermined interval. One capacitor electrode 16 a of the capacitor element 3 is formed integrally with one discharge electrode 15 a of the ESD protection element 2. For this reason, the capacitor element 3 and the ESD protection element 2 are always in a fixed positional relationship, and electrical characteristics such as inductance between them are stable and do not fluctuate.

  In the above, the case where the ESD protection element 2 and the capacitor element 3 are integrally formed inside the electronic component built-in substrate 1 is shown. However, instead of the capacitor element 2, as shown in FIG. The element 2 and the inductor element 17 may be integrally formed. 3A is an equivalent circuit diagram, and FIGS. 3B and 3C are partial cross-sectional views. FIG. 3C shows a YY portion of FIG.

  The inductor element 17 is formed by connecting inductor electrodes 18 a, 18 b, and 18 c with vias 19. The inductor electrode 18a is formed integrally with one discharge electrode 15a of the ESD protection element 2.

  In addition, as shown in FIG. 4, the ESD protection element 2, the capacitor element 3, and the inductor element 17 may be integrally formed inside the electronic component built-in substrate 1. 4A is an equivalent circuit diagram, and FIGS. 4B and 4C are partial cross-sectional views. FIG. 4C shows a ZZ portion of FIG.

  In this modification, one discharge electrode 15a of the ESD protection element 2, one capacitor electrode 16a of the capacitor element 3, and an inductor electrode 18a of the inductor element 17 are integrally formed.

  As mentioned above, although the electronic component built-in board concerning the embodiment of the present invention, the electronic module using the same, and the modification were explained, the present invention is not limited to these contents. For example, the type of electronic component element formed integrally with the ESD protection element 2, the connection structure with the ESD protection element 2, the equivalent circuit, etc. are arbitrary, and various modifications can be made. Moreover, the electronic circuit comprised by an electronic module is also arbitrary and can comprise various electronic circuits.

  Next, an example of an electronic component built-in substrate according to the present embodiment and an electronic module manufacturing method using the same will be described. Here, the case where the ESD protection element 2 and the capacitor element 3 are integrally formed (in the case of the configuration of FIG. 2) is shown.

  The electronic component built-in substrate 1 is manufactured by stacking and firing a plurality of ceramic green sheets.

  First, an insulating ceramic powder having a predetermined composition was mixed with a solvent, a binder, and the like to form a slurry, and the slurry was formed into a thin plate by a doctor blade method to form a ceramic green sheet.

  Further, an electrode paste was formed by mixing Cu powder having a predetermined particle diameter with a solvent, a binder, and the like.

  Also, a mixed paste in which the ceramic powder used for the ceramic green sheet and the Cu powder used for the electrode paste are mixed at a predetermined ratio, and further mixed with a solvent, a binder, etc., and an insulating material and a metal material are mixed. Formed.

  Next, a hole for forming the via 5 was provided in the ceramic green sheet. The position and number of holes differ depending on the ceramic green sheet. And the electrode paste was filled in the hole of the ceramic green sheet.

  Next, a mixed paste for forming the mixing portion 14 is applied in a predetermined shape on a ceramic green sheet that forms part of the ESD protection element 2 and the capacitor element 3, and the discharge electrode 15a is further formed thereon. The electrode paste for forming 15b was applied in a predetermined shape, and the resin paste that disappeared when fired to form the cavity 13 was applied thereon. Since the discharge electrode 15a is formed integrally with the capacitor electrode 16a of the capacitor element 3, the electrode paste is applied in such a shape. In the case where a sealing layer is formed under the mixing portion 14 and on the ceiling portion of the cavity portion 13, a resin paste for forming the cavity portion 13 and before applying the mixed paste for forming the mixing portion 14. After applying, for example, an alumina paste for forming a seal layer is applied.

  Further, an electrode paste for forming the internal wiring 4, the internal ground electrode 6, the capacitor elements 3 and 7, and the inductor element 8 was applied to a predetermined ceramic green sheet in a predetermined shape.

  Next, a ceramic green sheet for forming the ESD protection element 2 and other ceramic green sheets were laminated in a predetermined order and in a predetermined order, and pressed to form an unfired ceramic laminated body.

  Next, land electrodes for forming external ground electrodes 9 and terminal electrodes 10 on the lower surface of the ceramic laminate and used for mounting electronic component elements (IC element 11, SAW element 12, etc.) are formed on the upper surface. For this purpose, a conductive paste was applied in a predetermined shape. In addition, you may apply | coat these electrically conductive pastes beforehand to the ceramic green sheet laminated | stacked on the uppermost layer or the lowest layer instead of apply | coating at this stage.

  Next, the ceramic laminate was fired with a predetermined profile to manufacture the electronic component built-in substrate 1. An ESD protection element 2 is integrally formed with the capacitor element 3 inside the electronic component built-in substrate 1. In the above description, the case where one electronic component built-in substrate is manufactured has been described. However, a plurality of electronic component built-in substrates may be manufactured at a time from a large ceramic laminate. Before or after firing, the large ceramic laminate is cut to the size of each electronic component built-in substrate.

  Finally, the IC module 11 and the SAW element 12 were mounted on the electronic component built-in substrate 1 using a conventional method, thereby completing the electronic module according to the present embodiment.

(Application examples)
As an application example, a high-frequency switching module (electronic module) shown in FIG. 5 was manufactured.

  In this high-frequency switching module, an ESD protection element 2, a capacitor element 3, an inductor element 17, and other capacitor elements C and an inductor element L are formed inside an electronic component built-in substrate, and an IC element 11 and a SAW element (SAW duplexer). Element) 12 is mounted on the surface of the electronic component built-in substrate to constitute a circuit of a high-frequency switching module.

  FIG. 6A to FIG. 10L are stacked diagrams of electronic component built-in substrates. That is, the electronic component built-in substrate is formed in a multilayer structure, and FIGS. 6A to 10L show the uppermost layer to the lowermost layer in order, and electrode patterns, vias, etc. appearing on the upper surface of each layer. Show. However, FIG. 10 (L) only shows an electrode pattern on the lower surface of the layer shown in FIG. 10 (N), that is, the lower surface of the electronic component built-in substrate.

  8 (G), (H), (I), and FIG. 9 (J), inductor electrodes 18a, 18b, 18c, and 18d constituting the inductor element 17 are formed.

  Further, in FIG. 10M, a mixing portion 14 and discharge electrodes 15a and 15b constituting the ESD protection element 2 are formed. Reference numeral 13 denotes a cavity formed on this layer.

  10 (M) and 10 (N), capacitor electrodes 16a and 16b constituting the capacitor 3 are formed. In FIG. 10N, a part of the large internal ground electrode 6 forms a capacitor electrode 16b.

1: Electronic component built-in substrate 2: ESD protection element 3: Capacitor element 4: Internal wiring 5: Via 6: Internal ground electrode 9: External ground electrode 10: Terminal electrode 11: IC element 12: SAW element (SAW duplexer element)
13: Cavity 14: Mixing part 14a: Insulating material 14b: Metal material 15a, 15b: Discharge electrode 16a, 16b: Capacitor electrode 17: Inductor elements 18a, 18b, 18c: Inductor electrode 19: Via (for inductor element)

Claims (7)

In an electronic component built-in board having at least one electronic component element built therein,
The electronic component built-in substrate further includes an ESD protection element inside,
The ESD protection element comprises at least a cavity formed inside the electronic component built-in substrate and a pair of discharge electrodes formed to face each other in the cavity,
The electronic component built-in substrate, wherein the ESD protection element is formed integrally with the electronic component element.   2. The electronic component built-in according to claim 1, wherein at least one of the pair of discharge electrodes of the ESD protection element and a part of the components of the electronic component element are integrally formed. substrate.   The ESD protection element further includes a mixing portion made of a mixed material including a metal material and an insulating material constituting the electronic component built-in substrate at the bottom of the cavity portion, and the pair of discharge electrodes includes the mixing electrode. The electronic component built-in substrate according to claim 1, wherein the electronic component-embedded substrate is formed on a portion.   4. The electronic component built-in substrate according to claim 1, wherein two or more ESD protection elements are formed inside the electronic component built-in substrate. 5.   5. The electronic component built-in substrate according to claim 1, wherein the electronic component element is a capacitor element, an inductor element, or a composite electronic component element of a capacitor element and an inductor element.   6. An electronic module, further comprising an electronic component element mounted on the surface of the electronic component built-in substrate according to any one of claims 1 to 5.   The electronic module according to claim 6, wherein the electronic component element mounted on the surface of the electronic component built-in substrate is an IC element or a SAW element.