Power module

Abstract

This power module comprises an IC chip and an inductor positioned so as to overlap the IC chip in a first direction. The IC chip has: a non-exposed portion that overlaps the inductor when viewed along the first direction; and an exposed portion that is exposed from the inductor. The inductor has a terminal that extends along the outer shape of the exposed portion and is mounted on a substrate.

Description

Power Module

[0001] The present disclosure relates to a power module.

[0002] Patent Document 1 discloses a power supply device including N inductors and N power modules associated with the N inductors.

[0003] Japanese Patent Application Laid-Open No. 2020-65428

[0004] In the power supply device of Patent Document 1, the inductor and the power module corresponding to the inductor are positioned so as not to overlap, which may result in a large mounting area for the inductor and power module on a printed circuit board. If the mounting area is large, the heat generated by the inductor may become greater than the heat generated by the power module under light loads, and the heat generated by the power module may become greater than the heat generated by the inductor under heavy loads, which may result in uneven heat generation between the inductor and the power module.

[0005] An object of the present disclosure is to provide a power module that can improve the uniformity of heat generation in IC chips and inductors.

[0006] A power module according to one aspect of the present disclosure comprises an IC chip and an inductor positioned to overlap the IC chip in a first direction, wherein the IC chip has a non-exposed portion that overlaps the inductor when viewed along the first direction and an exposed portion that is exposed from the inductor, and the inductor has a terminal that extends along the outline of the exposed portion and is mounted on a substrate.

[0007] According to the power module of the above aspect, it is possible to improve the uniformity of the heat generation amount of the IC chip and the inductor.

[0008] 2 is a perspective view showing a power module according to one embodiment of the present disclosure; FIG. 3 is a plan view of the power module of FIG. 1; FIG. 4 is a cross-sectional view taken along line III-III of FIG. 2; FIG. 5 is a cross-sectional view taken along line IV-IV of FIG. 2; FIG. 6 is a cross-sectional view showing a first modified example of the power module of FIG. 1; and FIG. 7 is a plan view showing a second modified example of the power module of FIG. 1.

[0009] Various aspects of the present disclosure will now be described.

[0010] A first aspect of the power module comprises an IC chip and an inductor positioned to overlap the IC chip in a first direction, wherein the IC chip has a non-exposed portion that overlaps the inductor when viewed along the first direction and an exposed portion that is exposed from the inductor, and the inductor has a terminal that extends along the outer shape of the exposed portion and is mounted on a substrate.

[0011] The power module of the second aspect is the power module of the first aspect, further comprising a plurality of the IC chips and a plurality of the inductors, wherein a pair of one IC chip and one inductor is positioned side by side along a second direction intersecting the first direction, and at least one of the terminals is positioned between adjacent IC chips.

[0012] A power module of a third aspect is the power module of the first or second aspect, wherein each of the plurality of inductors has a core and a coil wound around the core, and the coil is configured from a single strip-shaped winding.

[0013] A fourth aspect of the power module is the power module of the third aspect, wherein the core has a winding portion around which the coil is wound, and a first portion and a second portion located at both ends of the winding portion, and the inductor has a planar portion including an imaginary plane on which outer surfaces of the first portion and the second portion and the outer surface of the coil are located.

[0014] A power module of a fifth aspect is the power module of the fourth aspect, further comprising a heat sink in contact with the flat portion.

[0015] A power module of a sixth aspect is the power module of any one of the first to fifth aspects, wherein the IC chip has a portion made of silicon, and the portion made of silicon is located in the exposed portion.

[0016] A seventh aspect of the power module is the power module of any one of the first to sixth aspects, wherein the terminals are located in positions that do not overlap with the IC chip in a first direction and extend in a direction from the non-exposed portion toward the exposed portion.

[0017] The power module of an eighth aspect is the power module of any one of the first to seventh aspects, further comprising the substrate having a mounting portion on which the terminals are mounted, and when viewed along the first direction, an end of the mounting portion on the exposed portion side in a direction from the non-exposed portion toward the exposed portion is at the same position as the exposed portion or farther from the non-exposed portion than the exposed portion in the direction from the non-exposed portion toward the exposed portion.

[0018] A power module of a ninth aspect is the power module of any one of the first to eighth aspects, wherein the thickness of the terminals in the first direction is smaller than the thickness of the IC chip in the first direction.

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description does not limit the present disclosure, but is essentially merely illustrative, and appropriate modifications can be made without departing from the spirit of the present disclosure. The drawings are schematic, and the ratios of dimensions and the like do not necessarily correspond to reality.

[0020] 1, a power module 1 according to one aspect of the present disclosure includes an IC chip 10 and an inductor 20. The inductor 20 is positioned so as to overlap the IC chip 10 in a first direction (for example, the Z direction).

[0021] In this embodiment, the power module 1 is a four-phase module including a substrate 2, a plurality of IC chips 10 (for example, four IC chips 10), and a plurality of inductors 20 (for example, four inductors 20). The plurality of IC chips 10 and the plurality of inductors 20 are mounted on the substrate 2. A set of one IC chip 10 and one inductor 20 positioned so as to overlap this IC chip 10 is positioned side by side along a second direction (for example, the X direction) intersecting the first direction Z.

[0022] The IC chip 10 includes, for example, a lead frame or a resin molded body, and as shown in FIG. 2 , when viewed in the first direction Z, has a non-exposed portion 11 overlapping the inductor 20 and an exposed portion 12 exposed from the inductor 20. In this embodiment, when viewed in the first direction Z, the IC chip 10 has a generally rectangular shape with its short sides extending along the second direction X and its long sides extending along a third direction (e.g., the Y direction) intersecting the first direction Z and the second direction X. The non-exposed portion 11 is larger than the exposed portion 12. A gap is formed between the non-exposed portion 11 of the IC chip 10 and the inductor 20 (see FIG. 4 ). The IC chip 10 has a portion 13 made of silicon. The portion 13 is located in the exposed portion 12. The silicon portion 13 includes, for example, a MOSFET and a control unit.

[0023] The inductor 20 has a terminal 21 that extends along the outer shape of the exposed portion 12 of the IC chip 10 and is mounted on the substrate 2. In this embodiment, the inductor 20 has a core 22 and a coil 23 wound around the core 22. The terminal 21 is adjacent to the IC chip 10 (in other words, it is located in a position that does not overlap with the IC chip 10 in the first direction Z) and extends from the coil 23 along the substrate 2 in a third direction (e.g., the Y direction) and in a direction from the non-exposed portion 11 toward the exposed portion 12. In all of the inductors 20, the terminal 21 is located on the same side of the IC chip 10 in the second direction X (e.g., on the right side of the IC chip 10 in FIG. 2 ) when viewed along the first direction Z. The terminal 21 is mounted on a mounting portion 6 of the substrate 2. As shown in FIG. 2 , the mounting portion 6 extends in a direction from the non-exposed portion 11 toward the exposed portion 12 (e.g., the third direction Y) when viewed along the first direction Z. An end 61 of the mounting portion 6 on the exposed portion 12 side in the third direction Y is at a position equal to or farther from the unexposed portion 11 than the exposed portion 12 in the third direction Y. In other words, the mounting portion 6 extends along the third direction Y to a position equal to or farther from the inductor 20 than the IC chip 10. As shown in Figure 4, the thickness W1 of the terminal 21 in the first direction Z is smaller than the thickness W2 of the IC chip 10 (unexposed portion 11 in Figure 4) in the first direction Z.

[0024] The core 22 includes a first portion 221 , a second portion 222 and a winding portion 223 .

[0025] 1 , the first portion 221 and the second portion 222 have a substantially rectangular parallelepiped shape extending along the second direction X. The first portion 221 is located closer to the exposed portion 12 in the third direction Y than the second portion 222. As an example, the first portions 221 of the cores 22 of the four inductors 20 are connected to each other and constitute a single member, and the second portions 222 of the cores 22 of the four inductors 20 are connected to each other and constitute a single member.

[0026] The winding portion 223 has a substantially rectangular parallelepiped shape extending along the third direction Y, and the coil 23 is wound around it as shown in FIGS. 3 and 4 . In this embodiment, the core 22 has four winding portions 223 positioned at equal intervals along the second direction X. As shown in FIG. 3 , the winding portion 223 includes a first protrusion 2231 and a second protrusion 2232. The first protrusion 2231 extends from the first portion 221 toward the second portion 222 along the third direction Y. The second protrusion 2232 extends from the second portion 222 toward the first portion 221 along the third direction Y. As an example, a gap is formed between the first protrusion 2231 and the second protrusion 2232. As shown in Fig. 4 , the surfaces of the first portion 221 and the second portion 222 that do not face the IC chip 10 in the first direction Z are referred to as first surfaces 2201 (Fig. 4 shows the first surface 2201 of the second portion 222). The surfaces of the first protrusion 2231 and the second protrusion 2232 that do not face the IC chip 10 in the first direction Z are referred to as second surfaces 2202 (Fig. 4 shows the second surface 2202 of the second protrusion 2232). The second surface 2202 is located closer to the IC chip 10 in the first direction Z than the first surface 2201. The coil 23 is located between the first surface 2201 and the second surface 2202 in the first direction Z.

[0027] The coil 23 is made up of a single band-shaped winding, as shown in Figures 3 and 4. In this embodiment, the coil 23 has a substantially C-shape, as shown in Figure 4, and both ends of the coil 23 are connected to the substrate 2.

[0028] The power module 1 can provide the following effects.

[0029] The power module 1 includes an IC chip 10 and an inductor 20 positioned to overlap the IC chip 10 in a first direction Z. When viewed along the first direction Z, the IC chip 10 has a non-exposed portion 11 that overlaps the inductor 20 and an exposed portion 12 that is exposed from the inductor 20. The inductor 20 has a terminal 21 that extends along the outer shape of the exposed portion 12. This configuration can improve the uniformity of the heat generation amounts of the IC chip 10 and the inductor 20. Because the IC chip 10 and the inductor 20 overlap in the first direction Z, the mounting area of ​​the power module 1 can be reduced. Because the terminal 21 extends along the outer shape of the exposed portion 12, heat generated in the IC chip 10 can be dissipated via the terminal 21.

[0030] For example, by configuring the inductor 20 to cover a portion of the IC chip 10, the appearance of the input capacitor or decoupling capacitor can be visually or automatically inspected. This makes it possible to detect open defects such as chip lift. Components that are covered by the inductor 20 and cannot be visually inspected can be electrically inspected when they are open or shorted. Therefore, by mounting electrically detectable components so that they are covered by the inductor 20, and mounting electrically undetectable components in positions not covered by the inductor 20, it is possible to inspect all components. Components that cannot be electrically detected include, for example, decoupling capacitors whose I / O terminals do not extend outside the power module 1.

[0031] The power module 1 includes multiple IC chips 10 and multiple inductors 20. A pair of one IC chip 10 and one inductor 20 is aligned along the second direction X. For example, assume that the power module 1 is configured as a four-phase module including four IC chips 10 and four inductors 20. By dividing the four-phase power module 1, two two-phase power modules 1 can be obtained (an example of a dicer cut line is shown by the dashed-dotted line L in FIG. 2). In this case, by sharing the footprint of the substrate 2 and enabling both the four-phase power module 1 and the two-phase power module 1 to be mounted, the manufacturing line and manufacturing process can be integrated, resulting in cost reduction. Furthermore, the four-phase power module 1 has the advantages of a coupled inductor, such as improved efficiency and response characteristics, but also requires a larger mounting area. Sharing the footprint of the substrate 2 allows for easy selection between the four-phase power module 1 and the two-phase power module 1. When dividing a four-phase power module 1 into two-phase power modules 1, if the cutting process is performed with the terminals 21 mounted on the substrate 2, the terminals 21 can prevent cracks from occurring in the substrate 2 and can conduct frictional heat generated during the cutting process. Furthermore, the terminals 21 can prevent the inductor 20 from falling off the substrate during the cutting process.

[0032] Each of the multiple inductors 20 has a core 22 and a coil 23 wound around the core 22. The coil 23 is configured with a single strip-shaped winding. With this configuration, the heat dissipation performance of the inductor 20 can be improved.

[0033] The IC chip 10 has a portion 13 made of silicon. The portion 13 made of silicon is located in the exposed portion 12. With this configuration, it is possible to prevent the silicon in the portion 13 made of silicon from deteriorating.

[0034] The terminals 21 are positioned so as not to overlap the IC chip 10 in the first direction Z, and extend in a direction from the non-exposed portion 11 toward the exposed portion 12. This configuration can improve the uniformity of the heat generation of the IC chip 10 and the inductor 20.

[0035] The power module 1 includes a substrate 2 having a mounting portion 6 on which terminals 21 are mounted. When viewed along the first direction Z, the end of the mounting portion 6 on the exposed portion 12 side in the direction from the non-exposed portion 11 toward the exposed portion 12 is located at the same position as the exposed portion 12 or farther from the non-exposed portion 11 than the exposed portion 12 in the direction from the non-exposed portion 11 toward the exposed portion 12. This configuration can improve the uniformity of the heat generation of the IC chip 10 and the inductor 20.

[0036] The thickness W1 of the terminal 21 in the first direction Z is smaller than the thickness W2 of the IC chip 10 in the first direction Z. Reducing the thickness W1 of the terminal 21 reduces the thermal conductivity of the terminal 21. This reduces the temperature difference between the terminal 21 and the portion of the IC chip 10 facing the terminal 21, thereby improving the uniformity of the heat generation of the IC chip 10 and the inductor 20.

[0037] The power module 1 can be configured as follows.

[0038] The components covered by the inductor 20 are not limited to electrically detectable components, and may include electrically undetectable components. In this case, the electrically undetectable components can be subjected to visual inspection by being arranged so that they are exposed from the inductor 20 when viewed in a direction other than the first direction Z (for example, the direction of arrow A shown in FIG. 3 ). In this way, including electrically undetectable components among the components covered by the inductor 20 increases the degree of freedom in the layout of the power module 1, and also makes it possible to increase the volume of the inductor 20 and improve the performance of the inductor 20.

[0039] Components that cannot be electrically detected should be placed in a location that allows visual inspection, as described above, or components that do not pose a risk of immediate failure even if they are open should be selected. This ensures the minimum performance of the power module 1 while improving performance such as efficiency, ripple voltage, and response characteristics. The power module 1 may have a two-story structure in which a power semiconductor or a substrate is provided on the inductor 20. A two-story structure using power semiconductors allows for the provision of a heat dissipation material such as a heat sink on the top surface, which is expected to improve efficiency. A two-story structure using a substrate increases the flexibility of the layout of the power module 1, making it easier to visually inspect components that cannot be electrically detected, for example.

[0040] 5 , the inductor 20 may be configured to have a planar portion 24 that includes an imaginary plane P on which the outer surfaces (e.g., first surface 2201) of the first portion 221 and the second portion 222 and the outer surface 231 of the coil 23 are located. In other words, the inductor 20 may be configured so that the first surface 2201 and the outer surface 231 of the coil 23 are located on the imaginary plane P. The imaginary plane P is a plane (e.g., an XY plane) that intersects with the first direction Z. For example, by providing a heat sink 300 in contact with the planar portion 24, the heat dissipation performance of the power module 1 can be improved.

[0041] As shown in FIG. 6 , when the planar electrodes 3 of the footprint of the board 2 are arranged in a grid pattern, a non-resist portion 5 may be provided around some of the planar electrodes 3 of the footprint of the board 2 (in FIG. 6 , one planar electrode 3 located in the upper left corner). Resist 4 is formed on the board 2 in areas other than the planar electrodes 3 and the non-resist portion 5. Because the non-resist portion 5 is a different color from the resist 4, the polarity of the board 2 can be determined without, for example, providing a notch in the planar electrodes 3. Image recognition is generally used to determine the polarity of components, and this is often determined by brightness. By providing the non-resist portion 5 with a color that is clearly different from the resist 4, the polarity of the board 2 can be more reliably determined. Furthermore, because there is no need to provide a notch in the planar electrodes 3, open defects due to smaller soldered areas can be prevented.

[0042] The power module 1 only needs to include at least one IC chip 10 and at least one inductor 20. For example, the substrate 2 and the heat sink 300 may be omitted.

[0043] The inductor 20 may have a configuration other than the configuration including the core 22 and the coil 23 .

[0044] The embodiments and modifications of the present disclosure can be combined with each other, or with modifications, or with each other. Features included in the embodiments and modifications of the present disclosure can also be combined with each other.

[0045] The disclosure of the present disclosure may vary in structural details, and changes in the combination and order of elements in each embodiment may be made without departing from the scope and spirit of the claimed disclosure.

[0046] REFERENCE SIGNS LIST 1 power module 2 substrate 3 planar electrode 4 resist 5 non-resist portion 6 mounting portion 61 end portion 10 IC chip 11 non-exposed portion 12 exposed portion 13 portion 20 inductor 21 terminal 22 core 2201 first surface 2202 second surface 221 first portion 222 second portion 223 winding portion 2231 first protrusion 2232 second protrusion 23 coil 231 outer surface 24 planar portion 300 heat sink

Claims

1. A power module comprising: an IC chip; and an inductor positioned so as to overlap the IC chip in a first direction, wherein the IC chip has, when viewed along the first direction, a non-exposed portion that overlaps the inductor and an exposed portion that is exposed from the inductor, and the inductor has a terminal that extends along the outline of the exposed portion and is mounted on a substrate.

2. The power module according to claim 1, comprising a plurality of said IC chips and a plurality of said inductors, wherein a pair of one said IC chip and one said inductor is positioned side by side along a second direction intersecting said first direction, and at least one said terminal is positioned between adjacent said IC chips.

3. A power module according to claim 1 or 2, wherein each of the plurality of inductors has a core and a coil wound around the core, and the coil is configured from a single strip-shaped winding.

4. A power module according to claim 3, wherein the core has a winding portion around which the coil is wound, and a first portion and a second portion located at both ends of the winding portion, and the inductor has a planar portion including an imaginary plane on which the outer surfaces of the first portion and the second portion and the outer surface of the coil are located.

5. The power module according to claim 4, further comprising a heat sink in contact with said flat portion.

6. A power module according to any one of claims 1 to 5, wherein the IC chip has a portion made of silicon, and the portion made of silicon is located in the exposed portion.

7. A power module according to any one of claims 1 to 6, wherein the terminals are located so as not to overlap the IC chip in the first direction, and extend in a direction from the non-exposed portion toward the exposed portion.

8. A power module according to any one of claims 1 to 7, comprising the substrate having a mounting portion on which the terminal is mounted, wherein when viewed along the first direction, an end of the mounting portion on the exposed portion side in a direction from the non-exposed portion toward the exposed portion is at the same position as the exposed portion or farther from the non-exposed portion than the exposed portion in the direction from the non-exposed portion toward the exposed portion.

9. A power module according to any one of claims 1 to 8, wherein the thickness of said terminals in said first direction is smaller than the thickness of said IC chip in said first direction.

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