JP2017195708A - Ic chip mounting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a down sized IC chip mounting substrate.SOLUTION: An IC chip mounting substrate comprises: a substrate 1 which has a pair of principal surfaces and a cavity 7 formed at least on one principal surface; a connection electrode 8 formed in the cavity 7; and a tabular IC chip S1 which has a pair of principal surfaces and a terminal electrode formed on one principal surface, in which the IC chip S1 is stored in the cavity 7; and the terminal electrode 9 is connected to the connection electrode 8 via a conductive bonding material 10; and the connection electrode 8 is formed on a side wall of the cavity 7; and the IC chip S1 is stored in the cavity 7 so as to make the principal surface of the IC chip S1 follow the side wall of the cavity 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an IC chip mounting substrate, and more particularly to a miniaturized IC chip mounting substrate.

  An IC chip mounting substrate in which an IC chip is mounted on a substrate is used in various electronic devices as an electronic module or the like.

  Patent Document 1 (WO2015-152333) discloses such an IC chip mounting substrate. Note that the IC chip mounting substrate disclosed in Patent Document 1 has a DC-DC converter module configured by mounting a switching IC or a capacitor as an IC chip on a multilayer substrate.

  FIG. 12 shows a DC-DC converter module (IC chip mounting substrate) 1000 disclosed in Patent Document 1.

  The DC-DC converter module 1000 includes a laminated substrate 101.

  Two switching ICs (ICs) 102 a and 102 b and two capacitors 103 a and 103 b are mounted on the main surface of the multilayer substrate 101.

WO2015-152333

  With downsizing of electronic devices, downsizing is also required for electronic components and electronic modules (IC chip mounting substrates, etc.) used in electronic devices. For example, smartphones, which are examples of electronic devices, are becoming smaller and thinner, and the vertical and horizontal dimensions of the built-in electronic components and modules are reduced (downsizing in the planar direction). ) And reducing the height dimension (reduction in size in the height direction = reduction in height) is strongly demanded.

  However, in the DC-DC converter module 1000 described above, the switching ICs 102a and 102b are mounted on the multilayer substrate 101 so that the main surface of the multilayer substrate 101 and the switching ICs 102a and 102b are parallel to each other. There is a problem that a large space for mounting the switching ICs 102a and 102b is required on the main surface, and the size is increased in the planar direction.

  Further, the DC-DC converter module 1000 has a problem that the switching ICs 102a and 102b and the like are mounted on the main surface of the multilayer substrate 101, so that the size is increased in the height direction.

  The present invention has been made to solve the above-described conventional problems. As a means for achieving this, the IC chip mounting substrate of the present invention has a pair of main surfaces, and a cavity is formed on at least one main surface. A substrate, a connection electrode formed in the cavity, and a plate-like IC chip having a pair of main surfaces and terminal electrodes formed on one main surface, the IC chip being a cavity The terminal electrode is connected to the connection electrode via a conductive bonding material, the connection electrode is formed on the side wall of the cavity, and the main surface of the IC chip is along the side wall of the cavity. Furthermore, the IC chip was accommodated in the cavity.

  The substrate may have a magnetic part formed of a magnetic material, and a coil having a winding axis in the depth direction of the cavity may be incorporated in the magnetic material part. In this case, an electronic module can be configured using a built-in coil. As described above, the IC chip mounting substrate of the present invention has the IC chip housed in the cavity so that the main surface of the IC chip is along the side wall of the cavity. Nevertheless, the magnetic flux formed by the coil is not easily affected by the IC chip.

  When the coil is built in the magnetic part, a non-magnetic layer made of a non-magnetic substance that extends in a direction parallel to the main surface of the substrate may be provided in the magnetic part. In this case, the DC superimposition characteristics of the coil can be improved by the nonmagnetic layer.

  The gap between the cavity and the IC chip may be filled with resin. In this case, the IC chip can be protected by the resin. Moreover, the strength of the substrate can be improved by the resin.

  A DC-DC converter module can be configured by using a switching IC for the IC chip.

  The IC chip mounting substrate of the present invention is miniaturized because the IC chip is accommodated in the cavity so that the main surface of the IC chip is along the side wall of the cavity formed on the substrate.

FIG. 1A is a perspective view showing a DC-DC converter module 100 according to the first embodiment. FIG. 1B is a cross-sectional view showing the DC-DC converter module 100. 2 is a perspective view of a main part of a DC-DC converter module 100. FIG. 2 is an equivalent circuit diagram of a DC-DC converter module 100. FIG. FIG. 4A-1 is a perspective view in the planar direction of the IC chip mounting substrate X according to the example. 4A-2 is a perspective view of the IC chip mounting board X in the side surface direction. FIG. 4B-1 is a perspective view in the planar direction of the IC chip mounting substrate Y according to the comparative example. FIG. 4B-2 is a perspective view of the IC chip mounting substrate Y in the side surface direction. FIG. 5A is a cross-sectional view illustrating steps performed in an example of a method for manufacturing the DC-DC converter module 100. FIG. 6B is a continuation of FIG. 5A, and is a cross-sectional view illustrating steps performed in an example of a method for manufacturing the DC-DC converter module 100. FIGS. 7C and 7D are continuations of FIG. 6B and are cross-sectional views illustrating steps performed in an example of a method for manufacturing the DC-DC converter module 100. FIG. FIGS. 8E and 8F are continuations of FIG. 7D, and are cross-sectional views illustrating steps performed in an example of a method for manufacturing the DC-DC converter module 100. FIGS. 9G and 9H are continuations of FIG. 8F and are cross-sectional views illustrating steps performed in an example of a method for manufacturing the DC-DC converter module 100, respectively. FIG. 10A is a perspective view showing a DC-DC converter module 200 according to the second embodiment. FIG. 10B is a cross-sectional view showing the DC-DC converter module 200. It is sectional drawing which shows the DC-DC converter module 300 concerning 3rd Embodiment. It is a perspective view which shows the conventional IC chip mounting substrate (DC-DC converter module 1000).

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

  Each embodiment shows an embodiment of the present invention exemplarily, and the present invention is not limited to the content of the embodiment. Moreover, it is also possible to implement combining the content described in different embodiment, and the implementation content in that case is also included in this invention. Further, the drawings are for helping understanding of the embodiment, and may not be drawn strictly. For example, a drawn component or a dimensional ratio between the components may not match the dimensional ratio described in the specification. In addition, the constituent elements described in the specification may be omitted in the drawings or may be drawn with the number omitted.

[First Embodiment]
In the first embodiment, the DC-DC converter module 100 is configured as an IC chip mounting substrate. That is, the IC chip mounting substrate of this embodiment has a function as a DC-DC converter module. FIG. 1A is a perspective view of the DC-DC converter module 100, FIG. 1B is a cross-sectional view thereof, FIG. 2 is a perspective view of essential parts, and FIG. 3 is an equivalent circuit diagram thereof.

  The DC-DC converter module 100 includes a multilayer substrate 1.

  The laminated substrate 1 has a structure in which a first non-magnetic part 1A, a magnetic part 1B, and a second non-magnetic part 1C are laminated in order from the bottom. The first nonmagnetic part 1A has a plurality of nonmagnetic layers 1a laminated thereon. In the magnetic body portion 1B, a plurality of magnetic body layers 1b are laminated. The second nonmagnetic portion 1C is formed by laminating a plurality of nonmagnetic layers 1c. The nonmagnetic parts 1A and 1C (nonmagnetic layers 1a and 1c) are made of low magnetic permeability or nonmagnetic ceramic. The magnetic body portion 1B (magnetic body layer 1b) is formed of a magnetic ceramic having a higher magnetic permeability than the nonmagnetic body portions 1A and 1C (nonmagnetic body layers 1a and 1c). As a material of the magnetic part 1B (magnetic substance layer 1b), for example, a magnetic ferrite ceramic is used. Specifically, ferrite containing iron oxide as a main component and containing at least one of zinc, nickel, and copper is used. As the material of the nonmagnetic parts 1A, 1C (nonmagnetic layers 1a, 1c), for example, nonmagnetic ferrite ceramics or insulating glass ceramics mainly composed of alumina and glass are used.

  In the first nonmagnetic portion 1A, internal wiring is formed by the wiring pattern 2 formed between the nonmagnetic layer 1a and the via electrode 3 formed through the nonmagnetic layer 1a. Yes. The wiring pattern 2 and the via electrode 3 are formed with silver as a main component, for example.

  A coil L1 is incorporated in the magnetic part 1B. The coil L1 is formed such that a coil pattern 4 formed between the magnetic layers 1b is spirally connected by via electrodes (not shown) formed through the magnetic layers 1b. The coil pattern 4 is formed with silver as a main component, for example. Further, in the magnetic part 1B, internal wiring is formed by the wiring pattern 2 formed between the magnetic layer 1b and the via electrode 3 formed through the magnetic layer 1b.

  Two capacitors C1 and C2 are built in the second nonmagnetic portion 1C. The capacitors C1 and C2 are each formed by a pair of opposing capacitor electrodes 5 formed between the nonmagnetic layers 1c. The capacitor electrode 5 is formed with silver as a main component, for example. The second nonmagnetic portion 1C has a wiring pattern (not shown) formed between the nonmagnetic layers 1c and a via electrode (not shown) formed through the nonmagnetic layer 1c. The internal wiring is formed.

  A plurality of mounting electrodes 6 that are used when the DC-DC converter module 100 is mounted on a substrate or the like are formed on the lower main surface of the multilayer substrate 1. The mounting electrode 6 is connected to an internal wiring formed on the first nonmagnetic body portion 1 </ b> A of the multilayer substrate 1. The mounting electrode 6 is shown as an input terminal T1, an output terminal T2, a control terminal T3, and a ground terminal T4 in the equivalent circuit diagram of FIG.

  A cavity 7 is formed in the central portion of the upper main surface of the multilayer substrate 1. The cavity 7 has a depth direction perpendicular to the main surface of the multilayer substrate 1.

  A connection electrode 8 is formed on the side wall of the cavity 7. As shown in FIG. 2, in the present embodiment, the connection electrode 8 includes the wiring pattern 2 and the via electrode 3 provided in the magnetic part 1 </ b> B and the second non-magnetic part 1 </ b> C to form the cavity 7. It was exposed by the cutting process.

  The cavity 7 accommodates a switching IC (IC chip) S1. The switching ICS1 has a plate shape, and in the present embodiment, the planar shape is rectangular. However, the shape in the plane direction is arbitrary and is not limited to a rectangle.

  As shown in FIG. 2, the switching IC S1 has a terminal electrode 9 formed on one main surface (bottom surface). A solder bump (conductive bonding material) 10 is formed in advance on the surface of each terminal electrode 9 of the switching ICS1. After the switching IC S1 is accommodated in the cavity 7, it is heated, the solder bumps 10 are reflowed, and naturally cooled again to be solidified, whereby the terminal electrodes 9 are connected to the connection electrodes 8 by the solder bumps 10. Yes. As a result, the main surface of the switching IC S1 is disposed substantially perpendicular to the main surface of the multilayer substrate 1.

  The size of the gap (clearance) between the side wall of the cavity 7 and the upper main surface (top surface) of the switching IC S1 is preferably about 50 μm to 500 μm. The size of the gap between the side wall of the cavity 7 and the side surface of the switching IC S1 is preferably about 50 μm to 500 μm in total on both sides. This is because it is difficult to accommodate the switching IC S1 in the cavity 7 if the gap is smaller than this. Further, if the gap is larger than this, the volume of the magnetic body portion 1B decreases, which is not preferable for the inductance formation of the coil L1. The size of the gap between the inner bottom surface of the cavity 7 and the side surface of the switching IC S1 is arbitrary, and the side surface of the switching IC S1 may be in contact with the inner bottom surface of the cavity 7 or may not be in contact therewith. .

  Resin 21 is filled in the gap between the cavity 7 and the switching IC S1. The resin 21 protects the switching IC S1 and improves the strength of the multilayer substrate 1.

  The DC-DC converter module 100 according to the first embodiment having the above structure has an equivalent circuit shown in FIG.

  The DC-DC converter module 100 includes an input terminal T1, an output terminal T2, a control terminal T3, and a ground terminal T4. A switching IC S1 and a coil L1 are connected between the input terminal T1 and the output terminal T2. The coil L1 functions as a choke coil. A connection point between the input terminal T1 and the switching IC S1 is connected to the ground terminal T4 via the capacitor C1. A connection point between the switching IC S1 and the output terminal T2 is connected to the ground terminal T4 via the capacitor C2. Furthermore, the control terminal T3 and the ground terminal T4 are each connected to the switching IC S1.

  The DC-DC converter module 100 according to the first embodiment having the above structure and equivalent circuit has the following features.

  The DC-DC converter module 100 is miniaturized because the switching IC S1 is accommodated in the cavity 7 so that the main surface of the switching IC S1 is along the side wall of the cavity 7. That is, since the DC-DC converter module 100 does not require a space for mounting the switching IC S1 on the main surface of the multilayer substrate 1, the size in the plane direction (vertical dimension and horizontal dimension) is suppressed. . Further, in the DC-DC converter module 100, since the switching IC S1 is accommodated in the cavity 7, the size in the height direction (height dimension) is also suppressed.

  Further, in the DC-DC converter module 100, since the switching IC S1 is accommodated in the cavity 7 so that the main surface of the switching IC S1 is along the side wall of the cavity 7, the magnetic flux formed by the coil L1 is changed to the switching IC S1. Hard to be disturbed by S1. Hereinafter, description will be given with reference to the drawings. 4A-1 and 4A-2, the IC chip 51 is mounted on the substrate so that the main surface of the IC chip 51 is perpendicular to the main surface of the substrate 52, as in the DC-DC converter module 100. An IC chip mounting substrate X according to an example embedded in 52 is shown. 4B-1 and 4B-2, the IC chip 61 is embedded in the substrate 62 so that the main surface of the IC chip 61 is parallel to the main surface of the substrate 62. The IC chip mounting substrate Y concerning a comparative example is shown. 4A-1 and 4B-1 are perspective views in a plane direction, and FIGS. 4A-2 and 4B-2 are perspective views in a side surface direction.

  In the IC chip mounting substrate X according to the example, as shown in FIGS. 4A-1 and 4A-2, the magnetic flux (indicated by the arrow) formed by the coil 53 is not easily disturbed by the IC chip 51. On the other hand, in the IC chip mounting substrate Y according to the comparative example, the magnetic flux (indicated by the arrow) formed by the coil 63 is generated by the IC chip 61 as shown in FIGS. It is hindered. As a result, when the coil 53 and the coil 63 are formed under the same conditions, the inductance value of the coil 53 is larger than the inductance value of the coil 63. The direct current superimposition characteristic of the coil 53 is superior to the direct current superimposition characteristic of the coil 63.

  In the DC-DC converter module 100, since the switching IC S1 is accommodated in the cavity 7 so that the main surface of the switching IC S1 is along the side wall of the cavity 7, the magnetic flux formed by the coil L1 is blocked by the switching IC S1. It is hard to be formed and has a large inductance value.

  Next, an example of a method for manufacturing the DC-DC converter module 100 according to the present embodiment will be described.

  First, as shown in FIG. 5A, the ceramic green sheet 11a for forming the nonmagnetic layer 1a, the ceramic green sheet 11b for forming the magnetic layer 1b, and the nonmagnetic layer 1c are formed. The ceramic green sheet 11c is prepared. The ceramic green sheets 11a and 11c are formed with nonmagnetic ferrite as a main component, for example. The ceramic green sheet 11b is formed, for example, with magnetic ferrite as a main component. Subsequently, as shown in FIG. 5A, holes 13 for forming the via electrodes 3 are formed in the ceramic green sheets 11a to 11c by a method such as irradiating laser light as necessary. .

  Next, as shown in FIG. 6B, the conductive paste 23 is filled into the holes 13 of the ceramic green sheets 11a to 11c. In addition, the conductive paste 22 for forming the wiring pattern 2, the conductive paste 24 for forming the coil pattern 4, and the conductivity for forming the capacitor electrode 5 are formed on the main surfaces of the ceramic green sheets 11a to 11c. The paste 25 and the conductive paste 26 for forming the mounting electrode 6 are respectively applied in a predetermined pattern shape. For the conductive pastes 22 to 26, for example, a conductive paste mainly composed of silver can be used. The filling of the conductive paste 23 and the application of the conductive pastes 22, 24, 25, and 26 can be performed simultaneously by screen printing, for example.

  Next, as shown in FIG. 7C, the ceramic green sheets 11a to 11c are laminated, pressed and integrated, and fired with a predetermined profile to produce the laminated substrate 1.

  Next, as shown in FIG. 7D, the upper main surface (top surface) of the multilayer substrate 1 is cut with a drill 71 or the like, and as shown in FIG. A cavity 7 is formed on the main surface of the substrate. At this time, the connection electrode 8 is exposed on the side wall of the cavity 7.

  Next, as illustrated in FIG. 8F, the switching IC S <b> 1 is accommodated in the cavity 7.

  Next, the laminated substrate 1 is heated at a predetermined temperature by, for example, reflow, the solder bumps 10 are melted, and then naturally cooled again to be solidified, and as shown in FIG. 9G, the terminal electrodes of the switching IC S1 ( 9 (G) is connected to the connection electrode 8 provided on the side wall of the cavity 7 by a solder bump (conductive bonding material) 10. At this time, since the switching IC S1 moves by self-alignment, the terminal electrode and the connection electrode 8 are reliably connected. In this step, the multilayer substrate 1 shown in FIG. 9G is rotated 90 degrees counterclockwise in the drawing so that the main surface on which the solder bumps 10 of the switching IC S1 are formed is on the lower side. In addition, it is preferable to do this. In this case, the self-alignment of the switching IC S1 is performed more appropriately.

  Next, as illustrated in FIG. 9H, a resin 21 is filled in a gap between the switching IC S <b> 1 and the cavity 7. As described above, the DC-DC converter module 100 according to the first embodiment is completed.

[Second Embodiment]
FIGS. 10A and 10B show a DC-DC converter module (IC chip mounting substrate) 200 according to the second embodiment. 10A is a perspective view of the DC-DC converter module 200, and FIG. 10B is a cross-sectional view.

  The DC-DC converter module 200 is a modification of the DC-DC converter module 100 according to the first embodiment.

  In the DC-DC converter module 100, as shown in FIG. 1B, capacitors C1 and C2 are formed between the nonmagnetic layers 1c of the second nonmagnetic portion 1C of the multilayer substrate 1, respectively. It was formed by a pair of opposing capacitor electrodes 5. Instead of this, the DC-DC converter module 200 includes capacitors C1 and C2 as separate components, and forms a land electrode 36 on the upper main surface (top surface) of the multilayer substrate 1 to provide capacitors C1 and C2. Was mounted on the land electrode 36.

  In the DC-DC converter module 100, the switching IC S1 is completely accommodated in the cavity 7, as shown in FIGS. Instead of this, the DC-DC converter module 200 exposes a part of the switching IC S1 to the outside of the cavity 7. Other configurations of the DC-DC converter module 200 are the same as those of the DC-DC converter module 100.

  In the DC-DC converter module 200 according to the second embodiment, the switching IC S1 is accommodated in the cavity 7 so that the main surface of the switching IC S1 is along the side wall of the cavity 7, and Since a space for mounting the switching IC S1 is not required, the size in the planar direction (vertical dimension and horizontal dimension) is suppressed. Further, in the DC-DC converter module 200, since the switching IC S1 is accommodated in the cavity 7 so that the main surface of the switching IC S1 is along the side wall of the cavity 7, the magnetic flux formed by the coil L1 is changed to the switching IC S1. Hard to be disturbed by S1. Furthermore, since the DC-DC converter module 200 can make the depth of the cavity 7 smaller than the DC-DC converter module 100, the strength of the multilayer substrate 1 is improved as compared with the DC-DC converter module 100.

[Third Embodiment]
FIG. 11 shows a DC-DC converter module (IC chip mounting substrate) 300 according to the third embodiment. FIG. 11 is a cross-sectional view of the DC-DC converter module 300.

  The DC-DC converter module 300 is a modification of the DC-DC converter module 100 according to the first embodiment. Specifically, one of the magnetic layers 1b constituting the magnetic portion 1B of the multilayer substrate 1 was replaced with a nonmagnetic layer 1x. The nonmagnetic layer 1x is formed of the same material as the nonmagnetic layer 1a and the nonmagnetic layer 1c. Other configurations of the DC-DC converter module 300 are the same as those of the DC-DC converter module 100.

  In the DC-DC converter module 300 according to the third embodiment, the direct current superposition characteristics of the coil L1 are improved by providing the nonmagnetic layer 1x.

  The DC-DC converter modules (IC chip mounting substrates) 100 to 300 according to the first to third embodiments have been described above. However, the present invention is not limited to the contents described above, and various modifications can be made in accordance with the spirit of the invention.

  For example, in the first to third embodiments, the DC-DC converter module is manufactured as the IC chip mounting substrate, but the manufactured electronic module is not limited to the DC-DC converter module. For example, an RFID module or an RF front end module may be used.

DESCRIPTION OF SYMBOLS 1 ... Laminated substrate 1A ... 1st nonmagnetic body part 1a ... Nonmagnetic body layer 1B ... Magnetic body part 1b ... Magnetic body layer 1C ... 2nd nonmagnetic body part 1c: Nonmagnetic layer 1x: Nonmagnetic layer (provided on the magnetic portion 1B)
2 ... wiring pattern 3 ... via electrode 4 ... coil pattern 5 ... capacitor electrode 6 ... mounting electrode 7 ... cavity 8 ... connection electrode 9 ... terminal electrode 10 ... Solder bump 21 ... Resin 36 ... Land electrode S1 ... Switching IC (IC chip)
T1 ... input terminal T2 ... output terminal T3 ... control terminal T4 ... ground terminal L1 ... coils C1, C2 ... capacitors 100, 200, 300 ... DC-DC converter module ( IC chip mounting board)

Claims (5)

A substrate having a pair of main surfaces and having a cavity formed in at least one of the main surfaces;
A connection electrode formed in the cavity;
A plate-shaped IC chip having a pair of main surfaces and terminal electrodes formed on one of the main surfaces;
The IC chip is accommodated in the cavity, and the terminal electrode is an IC chip mounting substrate connected to the connection electrode via a conductive bonding material,
An IC chip mounting substrate in which the IC chip is accommodated in the cavity such that the connection electrode is formed on a side wall of the cavity, and the main surface of the IC chip is along the side wall of the cavity.   2. The IC according to claim 1, wherein the substrate has a magnetic body portion formed of a magnetic body, and a coil having a winding axis in the depth direction of the cavity is built in the magnetic body portion. Chip mounting board.   The IC chip mounting substrate according to claim 2, wherein the magnetic body portion is provided with a nonmagnetic layer formed of a nonmagnetic material that extends in a direction parallel to the main surface of the substrate.   The IC chip mounting substrate according to any one of claims 1 to 3, wherein a resin is filled in a gap between the cavity and the IC chip. The IC chip mounting substrate according to any one of claims 1 to 4, wherein the IC chip is a switching IC and constitutes a DC-DC converter module.

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