JP6992406B2 - Manufacturing method of semiconductor device - Google Patents

Description

The techniques disclosed herein relate to methods of manufacturing semiconductor devices.

Patent Document 1 discloses a method for manufacturing a semiconductor device. This manufacturing method includes a step of arranging a laminate in which a semiconductor element and a heat sink are laminated in a mold, and injecting a resin into the mold to seal the laminate with the resin. The heat radiating plate is provided with a notch, and air bubbles generated in the resin injected into the mold are discharged from the notch of the heat radiating plate to the outside of the mold. This suppresses the generation of air bubbles inside the resin.

Japanese Unexamined Patent Publication No. 2016-134591

In the above technique, since the cutout portion is provided on the heat radiating surface (that is, the surface exposed to the outside) of the heat radiating plate, the heat radiating effect of the semiconductor device by the heat radiating plate can be significantly reduced. This specification discloses a technique for suppressing the generation of bubbles in the vicinity of a semiconductor element without significantly reducing the heat dissipation of the semiconductor device.

The method for manufacturing a semiconductor device disclosed in the present specification includes a step of preparing a laminate having a semiconductor element and a conductor member bonded to the semiconductor element, arranging the laminate in a mold, and in a mold. A step of sealing the laminate with the resin by injecting the resin is provided. The conductor member is formed with a hole or a groove having an opening on the peripheral side surface extending along the stacking direction of the laminated body. In the sealing step, the laminated body is arranged in the mold so that the opening of the hole or the groove of the conductor member is located at the planned merging point of the resin that wraps around the laminated body from two directions and merges.

When the resin is injected into the mold in which the laminate is arranged, the resin flowing in the mold wraps around the laminate from two directions and merges. Bubbles are likely to be formed inside the resin at the confluence. In this regard, in the above-mentioned manufacturing method, a hole or a groove is formed in the conductor member, and the laminate is arranged in the mold so that the opening of the hole or the groove is located at the planned merging point of the resin. .. As a result, the bubbles generated at the confluence of the resins flow into the holes or grooves of the conductor member, or are washed away by the resin that has passed through the holes or grooves of the conductor member. As a result, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element. Further, according to the above configuration, since the notch portion extending to the heat radiating surface as described above is not always required, the heat radiating property of the semiconductor device can be relatively maintained.

The sectional view of the semiconductor device is shown. The top view of the laminated body arranged in a mold is shown. The enlarged view of the conductor member in the sealing process is shown. The enlarged view of the conductor member in the sealing process of 2nd Example is shown. The top view of the conductor member of 3rd to 5th Examples is shown. The sectional view of the semiconductor device of 6th Example is shown. The sectional view of the semiconductor device of 7th Example is shown.

(First Example)
The semiconductor device 10 of the embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the semiconductor device 10. The semiconductor device 10 includes a laminate 12 and a mold resin 36. The laminate 12 is sealed in the mold resin 36. The mold resin 36 is made of a material having an insulating property. Although not particularly limited, the material constituting the mold resin 36 is a thermosetting resin material such as an epoxy resin. The laminated body 12 has a structure in which the upper surface side heat sink 20, the conductor member 26a, the semiconductor element 30, and the lower surface side heat sink 34 are laminated.

The semiconductor element 30 is a power semiconductor element such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor). Further, the semiconductor element 30 is configured by using various semiconductor materials such as silicon (Si), silicon carbide (SiC), and gallium nitride (GaN). Further, although not shown, upper surface electrodes and lower surface electrodes made of, for example, aluminum or other metals are formed on the upper surface and the lower surface of the semiconductor element 30.

The conductor member 26a is made of a conductive material such as copper or other metal. The conductor member 26a is generally a plate-shaped or block-shaped member, and has an upper surface, a lower surface located on the side opposite to the upper surface, and four side surfaces extending along the stacking direction of the laminated body 12. The conductor member 26a is located in the mold resin 36. The upper surface of the conductor member 26a is joined to the lower surface of the heat sink 20 on the upper surface side by a solder layer 22. Further, the lower surface of the conductor member 26a is joined to the upper surface of the semiconductor element 30 by a solder layer 28. As a result, the semiconductor element 30 is electrically and thermally connected to the upper surface side heat sink 20 via the conductor member 26a. Further, the conductor member 26a has four holes 24a having openings at each of the four corners (see FIG. 2). The hole 24a extends from the opening to the vicinity of the center of the conductor member 26a and does not penetrate the conductor member 26a. In order to maintain the heat dissipation of the semiconductor device 10, it is preferable that the hole 24a is formed at a position away from the semiconductor element 30.

The upper surface side heat sink 20 and the lower surface side heat sink 34 are made of a conductive material such as copper or other metal. The upper surface side heat sink 20 is generally a plate-shaped member. The lower surface of the heat radiating plate 20 on the upper surface side is joined to the upper surface of the conductor member 26a via the solder layer 22 inside the mold resin 36. As a result, the upper surface side heat sink 20 is electrically connected to the semiconductor element 30 via the conductor member 26a. On the other hand, the upper surface of the heat radiating plate 20 on the upper surface side is exposed to the outside of the mold resin 36 and functions as a heat radiating surface. The upper surface side heat sink 20 is also thermally connected to the semiconductor element 30 via the conductor member 26a, and the heat generated by the semiconductor element 30 is dissipated from the upper surface of the upper surface side heat sink 20 to the outside of the semiconductor device 10. Will be done.

Similarly, the lower surface side heat sink 34 is also a generally plate-shaped member. The upper surface of the lower surface side heat sink 34 is joined to the lower surface of the semiconductor element 30 via the solder layer 32 inside the mold resin 36. As a result, the lower surface side heat sink 34 is electrically connected to the semiconductor element 30. On the other hand, the lower surface of the lower surface side heat radiating plate 34 is exposed to the outside of the mold resin 36 and functions as a heat radiating surface. The lower surface side heat sink 34 is also thermally connected to the semiconductor element 30, and the heat generated by the semiconductor element 30 is radiated from the lower surface of the lower surface side heat sink 34 to the outside of the semiconductor device 10.

Subsequently, a method for manufacturing the semiconductor device 10 will be described with reference to FIGS. 2 and 3. Since the step of preparing the laminated body 12 is performed by a known method, detailed description thereof will be omitted. Therefore, in the following, only the step of sealing the laminated body 12 with the mold resin 36 will be described.

First, in the step of sealing the laminate 12 with the mold resin 36, the laminate 12 prepared by a known method is placed in the mold 60. FIG. 2 is a top view of the laminated body 12 arranged in the mold 60. The mold 60 includes a gate 62 for injecting the resin forming the mold resin 36 into the mold 60. For ease of understanding, FIG. 2 omits the illustration of the upper surface side heat sink 20 and the solder layer 22 included in the laminated body 12. Further, in FIG. 2, the four holes 24a included in the conductor member 26a are shown by broken lines. Generally, when the resin is injected into the mold 60 from the gate 62, the resin wraps around the laminate 12 from two directions and joins on the opposite side of the gate 62. In this embodiment, the laminated body 12 is arranged in the mold 60 so that the openings of at least one hole 24a are located at the planned merging points where the resins are expected to merge. The planned merging point of the resin is determined according to the specific configuration of the laminated body 12 and the mold 60, the fluidity of the resin, and the like, and can be predicted relatively accurately by experiments and simulations.

FIG. 3 shows an enlarged view of the conductor member 26a in a state where the resin is injected into the mold 60. In FIG. 3, the injected resin is hatched for ease of understanding. As shown in FIG. 3A, the injected resin wraps around the conductor member 26a from two directions and merges. Generally, in the resin flowing in the mold 60, the difference in flow velocity between the portion directly in contact with the mold 60 or the laminated body 12 and the portion not directly in contact with the mold 60 or the laminated body 12 Occurs. That is, the flow velocity in the portion directly in contact with the mold 60 or the laminated body 12 is higher than the flow velocity in the portion not directly in contact with the mold 60 or the laminated body 12 due to friction between the mold 60 or the laminated body 12. Become slow. For this reason, as shown in FIG. 3B, after the resins have merged, bubbles 70 may be generated at the junctions of the resins. In this embodiment, after the mold 60 is filled with the resin, the pressure in the mold 60 is kept constant (for example, several tens of MPa). In the process of holding the pressure, as shown in FIG. 3C, the bubble 70 flows into the hole 24a.

As described above, in this embodiment, the laminated body 12 is arranged in the mold 60 so that the opening of at least one hole 24a is located at the planned merging point where the resin is expected to merge. Therefore, in the modified example, the conductor member 26a does not have to have four holes 24a, and may have at least one hole 24a. However, in the configuration in which the conductor member 26a has four holes 24a as in the present embodiment, it is not necessary to consider the orientation in which the conductor member 26a is arranged in the step of preparing the laminated body 12. Therefore, the convenience in the process of preparing the laminated body 12 is improved.

(Effect of this example)
In this embodiment, the laminated body 12 is arranged in the mold 60 so that the hole 24a is formed in the conductor member 26a and the opening of the hole 24a is located at the planned merging point of the resin. As a result, the bubbles 70 generated at the resin merging point flow into the hole 24a located at the resin merging point. Therefore, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element 30. Further, in this embodiment, the hole 24a is formed in the conductor member 26a that does not function as a heat dissipation surface. Therefore, the heat dissipation of the semiconductor device 10 can be relatively maintained.

(Second Example)
Subsequently, a second embodiment will be described with reference to FIG. The second embodiment is different from the first embodiment in that the laminated body 12 includes the conductor member 26b instead of the conductor member 26a. Therefore, in the following, only the points different from those of the first embodiment will be described, and other explanations will be omitted. FIG. 4 shows an enlarged view of the conductor member 26b in a state where the resin is injected into the mold 60 in which the laminated body 12 of this embodiment is arranged. As shown in FIG. 4, the conductor member 26b has two holes 24b penetrating from one corner to the angle facing the one corner. Also in the second embodiment, in the step of sealing the laminated body 12 with the resin, the laminated body 12 is inside the mold 60 so that the opening of at least one hole 24b is located at the planned merging point of the resin. Is located in.

In FIG. 4A, the injected resin wraps around the conductor member 26b from two directions and joins. Further, the injected resin flows into the conductor member 26b through the opening of the hole 24b closest to the gate 62. Then, in FIG. 4B, after the resins have merged, bubbles 80 may be generated at the junctions of the resins. The resin injected from an opening other than the opening of the hole 24b located at the planned merging point further flows into the conductor member 26b. Then, in FIG. 4C, after the mold 60 is filled with the resin, the pressure in the mold 60 is kept constant (for example, several tens of MPa). Due to the pressure gradient generated in the pressure holding process, the resin passes through the hole 24b, and the resin flows out of the conductor member 26b from the opening of the hole 24b located at the planned confluence. As a result, the bubbles 70 are swept away from the vicinity of the semiconductor element 30 by the outflowing resin.

(Effect of this example)
In this embodiment, the bubbles 80 generated at the confluence of the resins are swept away by the resin that has passed through the holes 24b of the conductor member 26b. Therefore, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element 30. Further, since the hole 24b is formed in the conductor member 26b, the heat dissipation of the semiconductor device 10 can be relatively maintained.

(Third Example)
Subsequently, a third embodiment will be described with reference to FIG. The third embodiment is different from the first embodiment in that the laminated body 12 includes the conductor member 26c instead of the conductor member 26a. FIG. 5A shows a top view of the conductor member 26c. The conductor member 26c has one hole 24c with an opening in the vicinity of one corner thereof. For ease of understanding, in FIG. 5A, the hole 24c included in the conductor member 26c is shown by a broken line. In this embodiment, in the step of sealing the laminated body 12 with the resin, the laminated body 12 is arranged in the mold 60 so that the opening of the hole 24c is located at the planned merging point of the resin. As a result, the bubbles 70 generated at the confluence of the resins flow into the holes 24c located at the confluence. Therefore, also in this embodiment, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element 30. Further, since the hole 24c is formed in the conductor member 26c, the heat dissipation of the semiconductor device 10 can be relatively maintained.

(Fourth Example)
Subsequently, a fourth embodiment will be described with reference to FIG. The fourth embodiment is different from the first embodiment in that the laminated body 12 includes the conductor member 26d instead of the conductor member 26a. FIG. 5B shows a top view of the conductor member 26d. The conductor member 26d has four holes 24d with openings on each of its four sides. For ease of understanding, in FIG. 5B, the hole 24d included in the conductor member 26d is shown by a broken line. Unlike the first embodiment, when the resin merging point is in the vicinity of any one of the four side surfaces of the conductor member 26d, air bubbles generated at the resin merging point sufficiently flow into the hole 24a. May not. On the other hand, in this embodiment, since the conductor member 26d has a hole 24d having an opening on the side surface thereof, air bubbles generated at the confluence of the resins sufficiently flow into the hole 24d. Therefore, also in this embodiment, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element 30. Further, since the hole 24d is formed in the conductor member 26d, the heat dissipation of the semiconductor device 10 can be relatively maintained.

(Fifth Example)
Subsequently, a fifth embodiment will be described with reference to FIG. The fifth embodiment is different from the second embodiment in that the laminated body 12 includes the conductor member 26e instead of the conductor member 26b. FIG. 5C shows a top view of the conductor member 26e. The conductor member 26e has two holes 24e that penetrate from one side surface to the side surface facing the one side surface. For ease of understanding, in FIG. 5B, the hole 24e included in the conductor member 26e is shown by a broken line. Unlike the second embodiment, when the resin merging point is in the vicinity of any one of the four side surfaces of the conductor member 26e, air bubbles generated at the resin merging point sufficiently flow into the hole 24b. May not. On the other hand, in this embodiment, since the conductor member 26e has a hole 24e having an opening on the side surface thereof, air bubbles generated at the confluence of the resins sufficiently flow into the hole 24e. Therefore, also in this embodiment, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element 30. Further, since the hole 24e is formed in the conductor member 26e, the heat dissipation of the semiconductor device 10 can be relatively maintained.

(6th Example)
Subsequently, a sixth embodiment will be described with reference to FIG. The sixth embodiment is different from the first embodiment in that the laminated body 12 includes the conductor member 26f instead of the conductor member 26a. Therefore, in the following, only the points different from those of the first embodiment will be described, and other explanations will be omitted. FIG. 6 shows a cross-sectional view of the semiconductor device 10 of this embodiment. The conductor member 26f has a groove 24f formed on its upper surface. The groove 24f has an opening on the side surface of the conductor member 26f. The groove 24f is formed with irregularities on its surface so that the solder of the solder layer 22 in contact with the upper surface of the conductor member 26f does not flow into the groove 24f. The unevenness is formed by, for example, stripping of plating, plating treatment, surface roughening, or the like. In this embodiment, in the step of sealing the laminated body 12 with the resin, the laminated body 12 is arranged in the mold 60 so that the opening of the groove 24f is located at the planned merging point of the resin. As a result, the bubbles 70 generated at the confluence of the resins flow into the groove 24f located at the confluence. Therefore, also in this embodiment, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element 30. Further, since the groove 24f is formed in the conductor member 26f, the heat dissipation of the semiconductor device 10 can be relatively maintained.

(7th Example)
Subsequently, a seventh embodiment will be described with reference to FIG. 7. The seventh embodiment is different from the first embodiment in that the laminated body 12 includes the upper surface side heat sink 21 instead of the upper surface side heat sink 20 and the conductor member 26a. Therefore, in the following, only the points different from those of the first embodiment will be described, and other explanations will be omitted. FIG. 7 shows a cross-sectional view of the semiconductor device 10 of this embodiment. The upper surface side heat sink 21 has a convex portion 21a on the lower surface thereof.

The convex portion 21a is integrally configured with the upper surface side heat sink 21 by using a conductive material such as copper or other metal. The convex portion 21a has an upper surface, a lower surface located on the side opposite to the upper surface, and four side surfaces extending along the stacking direction of the laminated body 12. The convex portion 21a is located in the mold resin 36. The upper surface of the convex portion 21a is joined to the lower surface of the heat sink 21 on the upper surface side. Further, the lower surface of the convex portion 21a is joined to the upper surface of the semiconductor element 30 by a solder layer 28. As a result, the semiconductor element 30 is electrically and thermally connected to the heat radiating plate 21 on the upper surface side via the convex portion 21a. Further, the convex portion 21a has four holes 24g having openings in each of the four corners. The hole 24g extends from the opening to the vicinity of the center of the convex portion 21a and does not penetrate the convex portion 21a.

In this embodiment, in the step of sealing the laminated body 12 with the resin, the laminated body 12 is arranged in the mold 60 so that the opening of at least one hole 24 g is located at the planned merging point of the resin. As a result, the bubbles 70 generated at the confluence of the resins flow into the hole 24g located at the confluence. Therefore, also in this embodiment, it is possible to suppress the generation of bubbles in the vicinity of the semiconductor element 30. Further, since the hole 24g is formed in the convex portion 21a different from the heat radiating surface of the upper surface side heat radiating plate 21, the heat radiating property of the semiconductor device 10 can be relatively maintained.

Although some specific examples have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above. The technical elements described herein or in the drawings exhibit their technical usefulness alone or in various combinations.

10: Semiconductor device 12: Laminated body 20, 21: Top surface side heat sink 21a: Convex portion 22, 28, 32: Solder layer 24a, 24b, 24c, 24d, 24e, 24g: Hole 24f: Groove 26a, 26b, 26c, 26d, 26e, 26f, 26g: Conductor member 30: Semiconductor element 34: Bottom side heat sink 36: Mold resin 60: Mold 62: Gate 70, 80: Bubbles

Claims (1)

It is a manufacturing method of semiconductor devices.
A step of preparing a laminate having a semiconductor element and a conductor member bonded to the semiconductor element, and
A step of arranging the laminate in a mold and injecting a resin into the mold to seal the laminate with the resin is provided.
The conductor member has an opening on the peripheral side surface extending along the stacking direction of the laminated body, and a hole extending from the opening toward the central portion of the conductor member is located at a position not exposed from the resin after sealing. Is formed and
In the sealing step, the laminated body is placed in the mold so that the opening of the hole of the conductor member is located at a planned merging point of the resin that wraps around the laminated body from two directions and merges. Place in the manufacturing method.

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