JP6818801B2 - Power module and its manufacturing method - Google Patents

Description

The present invention relates to a power module and a method for manufacturing the same.

Conventionally, a power module in which a power chip including a semiconductor device such as an IGBT (Insulated Gate Bipolar Transistor) is mounted on a lead frame and the entire system is molded with a resin is known (for example, Patent Document 1 and Patent Document). See 2.). Since the semiconductor device generates heat in the operating state, it is common to dispose a heat sink on the back surface of the lead frame via an insulating layer to cool the semiconductor device.

Japanese Patent No. 3201277 Japanese Unexamined Patent Publication No. 2005-109100

Here, in the conventional power module, the insulating layer and the lead frame (metal layer) are in contact with each other in a plane. When an external force is applied while the insulating layer and the metal layer are in contact with each other on a flat surface in this way, the insulating layer and the metal layer may be displaced from each other, resulting in poor insulation. Further, if the insulating layer and the metal layer are displaced and a gap is provided between them, the thermal resistance of the module increases. As a result, the semiconductor device cannot be cooled as designed, so that thermal runaway of the semiconductor device, thermal deterioration of the bonding layer such as the solder layer, and fusing of the bonding wire occur.

An object of the present invention is to provide a power module having improved reliability and a method for manufacturing the same, in which the insulating layer and the metal layer are less likely to be displaced even when an external force is applied.

According to one aspect of the present invention, an insulating layer having an upper surface and a lower surface, a metal layer arranged on the upper surface side of the insulating layer, a semiconductor chip arranged on the metal layer, and the semiconductor chip. A part of the insulating layer on the surface of the metal layer facing the insulating layer, provided with at least a part of the metal layer and a mold resin covering at least a part of the upper surface side and the side surface of the insulating layer. The lower surface side of the insulating layer is flat, and the height of the end portion of the insulating layer covering the corner portion of the metal layer is higher than that of the lower surface of the metal layer and the metal layer is covered with a groove. A power module that is lower than the upper surface and has an end portion of the insulating layer interposed between the mold resin and the metal layer is provided.

According to another aspect of the present invention, an insulating layer having an upper surface and a lower surface, a parallel portion arranged on the upper surface side of the insulating layer, and a corner portion bent in a direction away from the insulating layer. A mold resin that covers at least a part of the metal layer, the semiconductor chip arranged in the parallel portion, the semiconductor chip, the metal layer, and at least a part of the upper surface side and the side surface of the insulating layer. with the door, the height of the end portion of the insulating layer covering the angle portion, the insulating the rather low upper surface of the lower surface from the high and the metal layer of the metal layer, between the mold resin and the metal layer A power module with intervening edges of the layer is provided.

According to another aspect of the present invention, a step of forming a groove on the lower surface of each of the first lead frame and the second lead frame, and a step of joining the semiconductor chip to the first lead frame using solder. And the step of performing ultrasonic bonding using an aluminum wire to electrically connect the semiconductor chip and the second lead frame, and arranging the first and second lead frames in a mold. A step of forming an insulating layer on the lower surfaces of the first and second lead frames so as to enter the groove, and after curing the insulating layer, the mold is closed and the mold resin is poured into the first and second lead frames. second lead frames, the solder, the semiconductor chip, the aluminum wire have a a step of molding, in the step of forming the insulating layer, said insulating layer having an upper surface and a lower surface, of the insulating layer The lower surface side is formed in a flat surface, and the height of the end portion of the insulating layer covering the corners of the first and second lead frames is higher than that of the lower surfaces of the first and second lead frames. It is lower than the upper surface of the first and second lead frames, and the end portion of the insulating layer covering the corner portion of the first lead frame is interposed between the mold resin and the first lead frame. Then, the end portion of the insulating layer covering the corner portion of the second lead frame is interposed between the mold resin and the second lead frame, and the first and second lead frames are formed. A method for manufacturing a power module that forms the insulating layer so as to be arranged on the upper surface side of the insulating layer is provided.

According to the present invention, it is possible to provide a power module having improved reliability and a method for manufacturing the same, in which the insulating layer and the metal layer are less likely to be displaced even when an external force is applied.

Schematic cross-sectional structure diagram of the power module according to the comparative example. Schematic cross-sectional structural view of another power module according to a comparative example. FIG. 6 is a schematic cross-sectional structure diagram showing a usage example of the power module shown in FIG. FIG. 6 is a schematic cross-sectional structure diagram showing a usage example of the power module shown in FIG. Schematic cross-sectional structural view of the power module according to the embodiment. The schematic plan structure view which shows the use example of the power module which concerns on embodiment. FIG. 5 is a schematic cross-sectional structure diagram along the line I-I shown in FIG. Another schematic cross-sectional structural view along the I-I line shown in FIG. Yet another schematic cross-sectional structural view along the I-I line shown in FIG. FIG. 6 is an enlarged schematic cross-sectional structure view of a part of the lead frame of the power module according to the embodiment. Another schematic cross-sectional structural view which enlarged a part of the lead frame of the power module which concerns on embodiment. Yet another schematic cross-sectional structural view in which a part of the lead frame of the power module according to the embodiment is enlarged. Yet another schematic cross-sectional structural view in which a part of the lead frame of the power module according to the embodiment is enlarged. Yet another schematic cross-sectional structural view in which a part of the lead frame of the power module according to the embodiment is enlarged. It is a process diagram which shows the manufacturing method of the power module which concerns on embodiment, (a) a sectional view which shows the state before forming a groove, (b) a sectional view which shows the state after forming a groove, (c). ) A cross-sectional view showing a state in which semiconductor chips are joined, (d) a cross-sectional view showing a state in which an aluminum wire is connected, (e) a cross-sectional view showing a state in which an insulating layer is formed, and (f) a cross-sectional view showing a molded state. .. FIG. 5 is a process diagram showing another manufacturing method of the power module according to the embodiment, wherein (a) a cross-sectional view showing a state before forming a groove, and (b) a cross-sectional view showing a state after forming a groove. (C) A cross-sectional view showing a state in which semiconductor chips are joined, (d) a cross-sectional view showing a state in which an aluminum wire is connected, (e) a cross-sectional view showing a molded state, and (f) a state in which an insulating layer is formed. Sectional view. It is a power module according to an embodiment, and is a schematic circuit representation diagram of a one-in-one module. A detailed circuit representation of a one-in-one module, which is a power module according to an embodiment. A schematic circuit representation diagram of a two-in-one module according to an embodiment. FIG. 6 is a schematic cross-sectional structure diagram of a SiC MOSFET, which is an example of a semiconductor device applied to a power module according to an embodiment. FIG. 6 is a schematic cross-sectional structural view of a SiC MOSFET including a source pad electrode SP and a gate pad electrode GP, which is an example of a semiconductor device applied to the power module according to the embodiment. An example of a circuit configuration in which a snubber capacitor is connected between a power supply terminal PL and a ground terminal NL in a schematic circuit configuration of a three-phase AC inverter configured by using the power module according to the embodiment. FIG. 6 is a schematic circuit configuration diagram of a three-phase AC inverter configured by using the power module according to the embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness of each component and the plane dimensions is different from the actual one. Therefore, the specific thickness and dimensions should be determined in consideration of the following explanation. In addition, it goes without saying that the drawings include parts having different dimensional relationships and ratios from each other.

Further, the embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the embodiments of the present invention include the material, shape, and structure of each component. , Arrangement, etc. are not specified as the following. The embodiments of the present invention can be modified in various ways within the scope of the claims.

(Comparison example)
The schematic cross-sectional structure of the power module 20a according to the comparative example is shown as shown in FIG. As shown in FIG. 1, first, the semiconductor chip 3 is joined to the lead frame 1 by using the solder 2. After that, the semiconductor chip 3 and the lead frame 5 are electrically connected to each other by using the aluminum wire 4. After that, the lead frame 1 and the lead frame 5 are arranged in a mold (not shown), and the surface opposite to the surface on which the semiconductor chip 3 of the lead frame 1 and the lead frame 5 is mounted (hereinafter referred to as "lower surface"). The insulating layer 7 is arranged there. After that, when the mold is closed and the mold resin 6 is poured, the power module 20a molded by the mold resin 6 is formed.

The schematic cross-sectional structure of another power module 20b according to the comparative example is shown as shown in FIG. As shown in FIG. 2, a structure in which a metal plate 8 is attached to the lower surface of the insulating layer 7 may be adopted. By arranging the metal plate 8 on the outermost layer in this way, the insulating layer 7 can be covered with the metal plate 8 to prevent injury. Other configurations are the same as those of the power module 20a.

The schematic cross-sectional structure showing the usage example of the power module 20a shown in FIG. 1 is shown as shown in FIG. 3, and the schematic cross-sectional structure showing the usage example of the power module 20b shown in FIG. 2 is shown in FIG. Represented as shown. As shown in FIGS. 3 and 4, the power modules 20a and 20b according to the comparative example are used by being screwed to the heat sink 10 via the liquid thermal compound 9.

Here, in the power modules 20a and 20b according to the comparative example, the insulating layer 7 and the lead frames (metal layers) 1 and 5 are in contact with each other in a plane. When an external force is applied while the insulating layer 7 and the metal layers 1 and 5 are in contact with each other in a plane in this way, the insulating layer 7 and the metal layers 1 and 5 may be displaced from each other, resulting in poor insulation. Further, when the insulating layer 7 and the metal layers 1 and 5 are displaced and a gap is formed between them, the thermal resistance of the module increases. As a result, the semiconductor device cannot be cooled as designed, so that thermal runaway of the semiconductor device, thermal deterioration of the bonding layer such as the solder 2, and melting of the aluminum wire 4 occur.

Further, since the thermal compound 9 is a liquid, not only is it time-consuming to apply, but it is also difficult to handle because it is necessary to apply it thinly and evenly. Further, since the entire module warps and returns and deforms due to repeated cooling and heating depending on the usage environment, the liquid thermal compound 9 is gradually pushed out (pump out). When the thermal compound 9 is extruded, a gap is formed between the lower surface of the module and the heat sink 10, and the thermal resistance of this portion increases. As a result, the semiconductor device cannot be sufficiently cooled, which causes thermal runaway of the semiconductor device described above, thermal deterioration of the bonding layer such as the solder 2, and fusing of the aluminum wire 4.

(Embodiment)
As shown in FIG. 5, the power module 20 according to the embodiment includes an insulating layer 7, lead frames (metal layers) 1 and 5 arranged on the insulating layer 7, and semiconductors arranged on the lead frame 1. A groove 11 is formed on the surface of the lead frames 1 and 5 facing the insulating layer 7 with the chip 3 so that a part of the insulating layer 7 can enter.

Here, the groove 11 may be formed outside the region where the heat generated from the semiconductor chip 3 is conducted.

Further, the angle between the semiconductor chip 3 and the groove 11 may be 45 ° or less.

Further, the groove 11 may be formed only outside the region where the heat generated from the semiconductor chip 3 is conducted.

Further, the cross-sectional shape of the groove 11 may be at least one of a rectangular shape, a semicircular shape, a semi-elliptical shape, a triangular shape, and a wedge shape.

Further, the grooves 11 may be formed in only one direction or in a grid pattern.

Further, the surfaces of the lead frames 1 and 5 facing the insulating layer 7 may be roughened.

Further, the insulating layer 7 may be made of a material softer than the lead frames 1 and 5.

Further, the hardness of the insulating layer 7 may be softer than that of A40 in terms of durometer hardness.

Further, the insulating layer 7 may be made of an organic material.

Further, the insulating layer 7 may be made of a silicone-based resin.

Further, the insulating layer 7 may be filled with a filler having high thermal conductivity.

Further, the filler may be at least one of aluminum oxide, silicon oxide, aluminum nitride, silicon nitride, boron nitride, beryllium, and magnesia.

Further, the insulating layer 7 may be formed before the semiconductor chip 3 is molded with the molding resin.

Further, the end portion of the insulating layer 7 may be interposed between the mold resin 6 and the lead frames 1 and 5.

Further, the insulating layer 7 may be formed after the semiconductor chip 3 is molded with the molding resin 6.

Further, the mold resin 6 and the lead frames 1 and 5 may be formed flush with each other.

(Power module)
Hereinafter, the configuration of the power module 20 according to the embodiment will be described in more detail with reference to FIG. As described above, in the power module 20 according to the embodiment, a groove 11 in which a part of the insulating layer 7 enters is formed on the surfaces of the lead frames 1 and 5 facing the insulating layer 7.

A flexible resin (organic material) is used for the insulating layer 7. The flexible resin is a material softer than the lead frames 1 and 5, and a resin having a durometer hardness softer than A40 (for example, a silicone resin) is desirable. Further, the resin used for the insulating layer 7 is filled with a filler having a high thermal conductivity of, for example, about 1 to 20 W / mK. As the filler, aluminum oxide, silicon oxide, aluminum nitride, silicon nitride, boron nitride, beryllium, magnesia and the like can be used.

In this way, if a flexible resin is used for the insulating layer 7, the insulating layer 7 enters the groove 11 without a gap, so that the insulating layer 7 can be combined with the lead frame 1 and the lead frame 5 without increasing the thermal resistance. Can be firmly joined (anchor effect). Further, due to its flexibility, the insulating layer 7 is sufficiently adapted to the surface of the heat sink 10, and it is not necessary to apply a liquid thermal compound 9 between the lower surface of the module and the heat sink 10 as in the comparative example.

As shown in the main portion B in FIG. 5, the groove 11 is formed outside the region extending downward by an angle C from the lower end portion of the solder 2. Since the heat generated from the semiconductor chip 3 spreads and conducts at about 45 °, it is desirable that this angle C is 45 ° or less. As a result, since there is no groove 11 in the region where heat is conducted, it is possible to avoid a problem that the thermal resistance becomes large, and it is possible to improve reliability.

(Example of use)
A schematic planar structure showing an example of use of the power module 20 according to the embodiment is shown as shown in FIG. As shown in FIG. 6, the lead frames 1 and 5 are screwed to the heat sink 10 by the screws 61 and 62. Of course, the screwing position and the number of screws can be changed as appropriate. According to such a configuration, the power module 20 can be firmly bonded to the heat sink 10 even if a flexible resin is used for the insulating layer 7.

(Groove formation direction)
The schematic cross-sectional structure along the I-I line shown in FIG. 5 is represented as shown in FIG. As shown in FIG. 7, a plurality of grooves 11 may be formed in the vertical direction. The vertical direction referred to here is the lateral direction of the power module 20. In this case, in particular, the bonding strength between the insulating layer 7 and the metal layers 1 and 5 can be increased against an external force applied in the longitudinal direction of the power module 20.

Another schematic cross-sectional structure along the I-I line shown in FIG. 5 is represented as shown in FIG. As shown in FIG. 8, a plurality of grooves 11 may be formed in the lateral direction. The lateral direction referred to here is the longitudinal direction of the power module 20. In this case, in particular, the bonding strength between the insulating layer 7 and the metal layers 1 and 5 can be increased against an external force applied in the lateral direction of the power module 20.

Yet another schematic cross-sectional structure along the I-I line shown in FIG. 5 is represented as shown in FIG. As shown in FIG. 9, the grooves 11 may be formed in a grid pattern. As a result, the bonding strength between the insulating layer 7 and the metal layers 1 and 5 can be further increased as compared with the case where the groove 11 is formed in one direction such as the vertical direction or the horizontal direction.

Here, the case where the grooves 11 are formed in the vertical direction, the horizontal direction, or the grid pattern is illustrated, but the formation direction of the grooves 11 is not limited to these. For example, the grooves 11 in one direction may be formed diagonally with respect to the semiconductor chip 3, or the grid-like grooves 11 may be formed diagonally.

(Cross-sectional shape of groove)
An enlarged schematic cross-sectional structure of a part of the lead frame 5 of the power module 20 according to the embodiment is shown as shown in FIG. As shown in FIG. 10, a rectangular groove 12 may be formed in a cross-sectional view. When the thickness of the lead frame 5 is, for example, about 3 mm, the depth of the groove 12 is preferably about 0.5 to 1.5 mm, for example. Further, it is desirable that the distance between the adjacent grooves 12 and the width of each groove 12 are about the same.

Another schematic cross-sectional structure in which a part of the lead frame 5 of the power module 20 according to the embodiment is enlarged is shown as shown in FIG. As shown in FIG. 11, a semicircular or semi-elliptical groove 13 may be formed in a cross-sectional view. The depth and spacing of such grooves 13 are also the same as in the case of the rectangular groove 12.

Yet another schematic cross-sectional structure obtained by enlarging a part of the lead frame 5 of the power module 20 according to the embodiment is shown as shown in FIG. As shown in FIG. 12, a triangular groove 14 may be formed in a cross-sectional view. The depth and spacing of such grooves 14 are also the same as in the case of the rectangular groove 12.

Yet another schematic cross-sectional structure in which a part of the lead frame 5 of the power module 20 according to the embodiment is enlarged is shown as shown in FIG. As shown in FIG. 13, a wedge-shaped groove 15 may be formed in a cross-sectional view. The depth and spacing of such grooves 15 are also the same as in the case of the rectangular groove 12.

Yet another schematic cross-sectional structure obtained by enlarging a part of the lead frame 5 of the power module 20 according to the embodiment is shown as shown in FIG. As shown in FIG. 14, the groove 16 may be formed by roughening the lower surfaces of the lead frame 1 and the lead frame 5 by sandblasting or etching. In this case, although the groove shape is indefinite, the same effect can be obtained in that the insulating layer 7 and the metal layers 1 and 5 are less likely to be displaced and the reliability is improved.

Here, a case where the grooves 12 to 15 are formed in a rectangular shape, a semicircular shape, a semi-elliptical shape, a triangle shape, and a wedge shape and a case where the groove 16 is formed by roughening the surface are illustrated, but these are mixed. It doesn't matter what you do. Further, although not particularly mentioned here, as shown in the main part B in FIG. 5, the grooves 12 to 16 may be formed outside the region extending downward by an angle C from the lower end portion of the solder 2. Of course.

(Manufacturing method 1)
The steps showing the manufacturing method of the power module 20 according to the embodiment are shown as shown in FIG. In FIG. 15, only a part on the lead frame 1 side is shown, but the other parts are as shown in FIG.

First, as shown in FIGS. 15A and 15B, a groove 11 is formed on the lower surface of lead frames 1 and 5 made of Cu, AL, or an alloy thereof. The method of forming the groove 11 is not particularly limited. For example, when the lead frames 1 and 5 are punched, the grooves 11 may be formed at the same time.

Next, as shown in FIG. 15C, the semiconductor chip 3 is bonded to the lead frame 1 using the solder 2. As the solder layer 2, a silver paste having a high thermal conductivity may be used.

Next, as shown in FIG. 15D, ultrasonic bonding is performed using an aluminum wire 4 in order to electrically connect the semiconductor chip 3 and the lead frame 5. At this time, the lead frame 1 and the lead frame 5 are connected to a connecting bar (not shown) so that their relative positions do not change during ultrasonic bonding. This connecting bar is removed after ultrasonic bonding.

Next, as shown in FIG. 15 (e), the lead frame 1 and the lead frame 5 are arranged in a mold (not shown), and the insulating layer 7 is formed on the lower surfaces of the lead frame 1 and the lead frame 5. The thickness of the insulating layer 7 is, for example, about 0.5 mm. The method of forming the insulating layer 7 may be screen printing or the like. At this time, the insulating layer 7 is formed so as to cover the corners P of the lead frames 1 and 5.

Finally, after the insulating layer 7 is cured, as shown in FIG. 15 (f), the mold is closed and the mold resin 6 is poured into the lead frame 1, the solder 2, the semiconductor chip 3, the aluminum wire 4, and the lead frame. Mold 5 As a result, the power module 20 molded by the mold resin 6 is manufactured.

According to such a manufacturing method, the end portion of the insulating layer 7 is interposed between the mold resin 6 and the lead frames 1 and 5. Therefore, the possibility of a short circuit at the corners P of the lead frames 1 and 5 can be reduced.

(Manufacturing method 2)
A step showing another method of manufacturing the power module 20 according to the embodiment is shown as shown in FIG. The difference from the manufacturing method 1 (FIG. 15) is that the molding step and the step of forming the insulating layer 7 are reversed.

First, FIGS. 16 (a) to 16 (d) are the same as those in FIGS. 15 (a) to 15 (d). That is, a groove 11 is formed on the lower surface of the lead frames 1 and 5, the semiconductor chip 3 is joined to the lead frame 1, and the semiconductor chip 3 and the lead frame 5 are connected by using an aluminum wire 4. Here, as shown in FIG. 16E, the mold is closed and the mold resin 6 is poured. At this time, the mold resin 6 and the lead frame 1 are made flush with each other at the corner portion P. Finally, as shown in FIG. 16 (f), the insulating layer 7 is formed on the surfaces of the flush mold resin 6 and the lead frames 1 and 5. Even in such a manufacturing method, since the corner portions P of the lead frames 1 and 5 are covered with the insulating layer 7, the possibility of a short circuit at the corner portions P can be reduced.

As described above, the power module 20 according to the embodiment is a resin-sealed semiconductor module having a vertical structure of a semiconductor chip / metal layer / insulating layer. In such a structure, a groove 11 in which a part of the insulating layer 7 enters is formed on the surface of the metal layers 1 and 5 facing the insulating layer 7. As a result, the bonding strength between the insulating layer 7 and the metal layers 1 and 5 is increased, so that the insulating layer 7 and the metal layers 1 and 5 are less likely to be displaced from each other even when an external force is applied, and insulation failure does not occur. Further, since the insulating layer 7 and the metal layers 1 and 5 are not displaced and a gap is not formed between them, the thermal resistance of the module is not increased. As a result, the semiconductor device can be cooled as designed, so that thermal runaway of the semiconductor device, thermal deterioration of the joint layer such as the solder 2, and melting of the aluminum wire 4 are eliminated, and the reliability is improved. Further, since the grooves 11 are arranged in consideration of heat spread so that the heat conduction generated in the semiconductor chip 3 is not hindered by the grooves 11, the cooling performance is not impaired. In addition, since a flexible resin is used for the insulating layer 7, a liquid thermal compound 9 is not required, and it is possible to provide a power module 20 that is easy to handle.

(Specific example of power module)
Hereinafter, a specific example of the power module 20 according to the embodiment will be described. Of course, the grooves 11 can also be formed in the lead frames 1 and 5 of the power module 20 described below. The formation direction, cross-sectional shape, and other details of the groove 11 are as described above.

The schematic circuit representation of the one-in-one module (1 in 1 Module) of the power module 20 according to the embodiment is shown as shown in FIG. Further, in the power module 20 according to the embodiment, the detailed circuit representation of the one-in-one module is shown as shown in FIG.

The power module 20 according to the embodiment includes a one-in-one module configuration. That is, one MOSFET Q is built in one module. As an example, 5 chips (MOS transistors x 5) can be mounted, and up to 5 MOSFET Qs can be connected in parallel. It is also possible to mount a part of the five chips for diode DI.

FIG. 17 shows a diode DI connected in antiparallel to the MOSFET Q. The main electrode of the MOSFET Q is represented by a drain terminal DT and a source terminal ST.

More specifically, as shown in FIG. 18, sense MOSFET Qs are connected in parallel with the MOSFET Q. The sense MOSFET Qs are formed as fine transistors in the same chip as the MOSFET Q. In FIG. 18, SS is a source sense terminal, CS is a current sense terminal, and G is a gate signal terminal. Also in the embodiment, in the semiconductor device Q, sense MOSFETs Qs are formed as fine transistors in the same chip.

Further, in the power module 20 according to the embodiment, a schematic circuit representation of the two-in-one module is shown as shown in FIG. As shown in FIG. 19, two MOSFETs Q1 and Q4 are built in one module. G1 is a gate signal terminal of MOSFET Q1, and S1 is a source sense terminal of MOSFET Q1. G4 is a gate signal terminal of MOSFET Q4, and S4 is a source sense terminal of MOSFET Q4. P is a positive power input terminal, N is a negative power input terminal, and O is an output terminal.

(Semiconductor device configuration example)
As an example of the semiconductor device 100 (Q) applied to the power module 20 according to the embodiment, the schematic cross-sectional structure of the SiC MOSFET has a semiconductor substrate 26 composed of an n ^- high resistance layer and a semiconductor, as shown in FIG. A gate insulating film 32 arranged on the surface of the semiconductor substrate 26 between the p-base region 28 formed on the surface side of the substrate 26, the source region 30 formed on the surface of the p-base region 28, and the p-base region 28. , The gate electrode 38 arranged on the gate insulating film 32, the source electrode 34 connected to the source region 30 and the p-base region 28, and the n ⁺ drain arranged on the back surface opposite to the front surface of the semiconductor substrate 26. A region 24 and a drain pad electrode 36 connected to the n ⁺ drain region 24 are provided.

In FIG. 20, the semiconductor device 100 is composed of a planar gate type n-channel vertical SiC MOSFET, but may be composed of a trench gate type n-channel vertical SiC MOSFET or the like.

Further, a GaN-based FET or the like can be applied to the semiconductor device 100 (Q) applied to the power module 20 according to the embodiment instead of the SiC MOSFET.

A SiC-based, GaN-based, or AlN-based power device can be applied to the semiconductor device 100 applied to the power module 20 according to the embodiment.

Further, as the semiconductor device 100 applied to the power module 20 according to the embodiment, a semiconductor having a bandgap energy of, for example, 1.1 eV to 8 eV can be used.

An example of the semiconductor device 100 applied to the power module 20 according to the embodiment, the schematic cross-sectional structure of the SiC MOSFET including the source pad electrode SP and the gate pad electrode GP is shown as shown in FIG. The gate pad electrode GP is connected to the gate electrode 38 arranged on the gate insulating film 32, and the source pad electrode SP is connected to the source electrode 34 connected to the source region 30 and the p base region 28.

Further, as shown in FIG. 21, the gate pad electrode GP and the source pad electrode SP are arranged on the passivation interlayer insulating film 44 that covers the surface of the semiconductor device 100. A transistor structure having a fine structure may be formed in the semiconductor substrate 26 below the gate pad electrode GP and the source pad electrode SP, as in the central portion of FIG. 20 or FIG.

Further, as shown in FIG. 21, in the transistor structure in the central portion, the source pad electrode SP may be extended and arranged on the interlayer insulating film 44 for passivation.

In the power module 20 according to the embodiment, a circuit configuration in which a snubber capacitor C is connected between the power supply terminal PL and the ground terminal NL is shown as shown in FIG. When the power module 20 according to the embodiment is connected to the power supply E, the inductance L of the connection line causes the switching speed of the SiC-based device to be high, so that a large surge voltage Ldi / dt is generated. For example, if the current change di = 300A and the time change dt = 100nsec associated with switching, then di / dt = 3 × 10 ⁹ (A / s). The value of the surge voltage Ldi / dt changes depending on the value of the inductance L, but the surge voltage Ldi / dt is superimposed on the power supply V. This surge voltage Ldi / dt can be absorbed by the snubber capacitor C connected between the power supply terminal PL and the ground terminal NL.

(Application example applying power module)
Next, with reference to FIG. 23, the three-phase AC inverter 40 configured by using the power module 20 according to the embodiment will be described.

As shown in FIG. 23, the three-phase AC inverter 40 includes a gate drive unit 50, a power module unit 52 connected to the gate drive unit 50, and a three-phase AC motor unit 54. The power module unit 52 is connected to U-phase, V-phase, and W-phase inverters corresponding to the U-phase, V-phase, and W-phase of the three-phase AC motor unit 54. Here, the gate drive unit 50 is connected to the SiC MOSFETs Q1 and Q4 in FIG. 23, but is also connected to the SiC MOSFETs Q2 and Q5 and the SiC MOSFETs Q3 and Q6, although not shown.

The power module unit 52 has an inverter-configured SiC MOSFETs Q1, Q4, Q2, Q5, and Q3, between the positive terminal (+) and the negative terminal (-) to which the converter 48 to which the storage battery (E) 46 is connected is connected. Q6 is connected. Further, diodes D1 to D6 are connected in antiparallel between the source and drain of the SiC MOSFETs Q1 to Q6.

In the power module 20 according to the embodiment, the structure of the single-phase inverter corresponding to the U-phase portion of FIG. 23 has been described, but the three-phase power is similarly formed even if it corresponds to the V-phase and the W-phase. The module portion 52 can also be formed.

The power module according to the present embodiment can be formed into any one-in-one, two-in-one, four-in-one, or six-in-one type.

As described above, according to the present invention, it is possible to provide a power module having improved reliability and a method for manufacturing the same, in which the insulating layer and the metal layer are less likely to be displaced even when an external force is applied.

[Other embodiments]
As mentioned above, although the present invention has been described by embodiment, the statements and drawings that form part of this disclosure are exemplary and should not be understood as limiting the invention. This disclosure will reveal to those skilled in the art various alternative embodiments, examples and operational techniques.

As described above, the present invention includes various embodiments not described here. For example, in FIG. 5, the insulating layer 7 is also formed between the lead frames 1 and 5, but the insulating layer 7 is not formed between the lead frames 1 and 5, and the lower surface of the lead frames 1 and 5 is formed. It does not matter if it is formed only.

The power module according to the present invention can be used for semiconductor modules such as an IGBT module, a diode module, and a MOS module (Si, SiC, GaN). It is also possible to use the case type module in a structure that does not use an insulating substrate such as DBC (Direct Copper Bond).

1,5 ... Metal layer (lead frame)
3 ... Semiconductor chip 6 ... Mold resin 7 ... Insulating layer 11, 12, 13, 14, 15, 16 ... Groove 20 ... Power module

Claims (23)

An insulating layer having an upper surface and a lower surface,
A metal layer arranged on the upper surface side of the insulating layer and
A semiconductor chip arranged on the metal layer and
A molding resin that covers at least a part of the metal layer and at least a part of the upper surface side and the side surface of the insulating layer is provided with the semiconductor chip.
A groove into which a part of the insulating layer enters is formed on the surface of the metal layer facing the insulating layer, and the lower surface side of the insulating layer is flat.
The height of the end portion of the insulating layer covering the corner portion of the metal layer is higher than the lower surface of the metal layer and lower than the upper surface of the metal layer, and the height of the insulating layer between the mold resin and the metal layer is high. A power module characterized by intervening ends. The power module according to claim 1, wherein the groove is formed outside a region in which heat generated from the semiconductor chip is conducted. The power module according to claim 2, wherein the angle between the semiconductor chip and the groove is 45 ° or less. The power module according to claim 2 or 3, wherein the groove is formed only outside the region where heat generated from the semiconductor chip is conducted. The power module according to any one of claims 1 to 4, wherein the cross-sectional shape of the groove is at least one of a rectangular shape, a semicircular shape, a semi-elliptical shape, a triangular shape, and a wedge shape. The power module according to any one of claims 1 to 5, wherein the grooves are formed in only one direction or in a grid pattern. The metal layer includes a first metal layer on which the semiconductor chip is arranged and a second metal layer that is electrically connected to the semiconductor chip via a wire, and the groove is the first metal layer. The power module according to any one of claims 1 to 6, wherein the power module is formed on a surface of the metal layer and the second metal layer facing the insulating layer. The metal layer includes a first metal layer and a second metal layer.
The groove into which a part of the insulating layer enters is formed on the surface of the first metal layer facing the insulating layer.
The power module according to any one of claims 1 to 6, wherein the surface of the second metal layer facing the insulating layer is roughened. An insulating layer having an upper surface and a lower surface,
A metal layer arranged on the upper surface side of the insulating layer and having a parallel portion along the insulating layer and a corner portion bent in a direction away from the insulating layer.
With the semiconductor chips arranged in the parallel portion,
A molding resin that covers at least a part of the metal layer and at least a part of the upper surface side and the side surface of the insulating layer is provided with the semiconductor chip.
The height of the end portion of the insulating layer covering the corner portion is higher than the lower surface of the metal layer and lower than the upper surface of the metal layer, and the end portion of the insulating layer is located between the mold resin and the metal layer. A power module characterized by being intervening. The power module according to any one of claims 1 to 9, wherein the surface of the metal layer facing the insulating layer is roughened. The power module according to any one of claims 1 to 10, wherein the insulating layer is made of a material softer than the metal layer. The power module according to claim 11, wherein the hardness of the insulating layer is a durometer hardness, which is softer than that of A40. The power module according to any one of claims 1 to 12, wherein the insulating layer is made of an organic material. The power module according to any one of claims 1 to 13, wherein the insulating layer is made of a silicone-based resin. The power module according to any one of claims 1 to 14, wherein the insulating layer is filled with a filler having high thermal conductivity. The power module according to claim 15, wherein the filler is at least one of aluminum oxide, silicon oxide, aluminum nitride, silicon nitride, boron nitride, beryllium, and magnesia. The power module according to any one of claims 1 to 16, wherein the insulating layer is formed before the semiconductor chip is molded with a molding resin. The semiconductor chip, SiC-based, is formed from one of the power devices of GaN-based, or AlN-based, current change rate di / dt is and greater than ^{3 × 10 8 (A / s} ) according Item 5. The power module according to any one of Items 1 to 17. The power module according to any one of claims 1 to 8, wherein the distance between adjacent grooves and the width of each groove are about the same. Any one of claims 1 to 18, wherein the mold resin is formed so as to cover the upper surface of the end portion of the insulating layer covering the corner portion and a part of the side surface of the end portion. The power module described in. The power module according to any one of claims 1 to 20, wherein the power module is formed in any one of one-in-one, two-in-one, four-in-one, and six-in-one types. A step of forming a groove on the lower surface of each of the first lead frame and the second lead frame, and
A step of joining a semiconductor chip to the first lead frame using solder,
A process of ultrasonically bonding using an aluminum wire to electrically connect the semiconductor chip and the second lead frame.
A step of arranging the first and second lead frames in a mold and forming an insulating layer on the lower surface of the first and second lead frames so as to enter the groove.
After curing the insulating layer, pouring a molding resin by closing the said mold, said first and second lead frames, the solder, the semiconductor chip, possess a step of molding the aluminum wire,
In the step of forming the insulating layer, the insulating layer has an upper surface and a lower surface, and the lower surface side of the insulating layer is formed on a flat surface to cover the corners of the first and second lead frames. The height of the end portion of the insulating layer is made higher than the lower surface of the first and second lead frames and lower than the upper surface of the first and second lead frames, and the mold resin and the first lead frame are made lower. The end portion of the insulating layer covering the corner portion of the first lead frame is interposed between the first lead frame, and the corner portion of the second lead frame is interposed between the mold resin and the second lead frame. A power characterized in that the end portion of the insulating layer covering the portion is interposed and the insulating layer is formed so that the first and second lead frames are arranged on the upper surface side of the insulating layer. How to make the module. The method for manufacturing a power module according to claim 22, wherein the insulating layer is formed so as to cover the corners of the first and second lead frames.

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