JP7367507B2 - power module - Google Patents

Description

The present invention relates to a semiconductor module, and particularly to a power module that controls large electric power.

In recent years, the electrification and electronic control of power sources in industrial machinery and vehicles (e.g. automobiles, railway vehicles) have been rapidly progressing from the viewpoint of energy conservation and precise operation control. The importance of power modules, which are responsible for power control, is increasing significantly.

In a power module, in order to control large electric power, a plurality of power semiconductor elements are usually connected in parallel, and each power semiconductor element is controlled simultaneously/synchronously. Typical power semiconductor elements used in power modules include, for example, IGBTs (Insulated Gate Bipolar Transistors), power MOSFETs (Power Metal Oxide Semiconductor Field Effect Transistors), and MOSGTO thyristors (MOS Gate Turn-Off thyristors). These power semiconductor elements are configured such that the output power is controlled by inputting a control signal to a signal electrode.

Since the power module, which is responsible for controlling the power of the power source, handles large amounts of electric power, ensuring the connection reliability of the electrical connections and electrical insulation of the circuit inside the power module is one of the most important issues. is generally sealed with a resin material so that no voids remain.

In addition, from the viewpoint of increasing the output of the power source, there is a demand for increasing the control power of the power module. Increasing the amount of control power means increasing the temperature difference between operating and resting states, leading to an increase in thermal stress and thermal strain within the power module. Fatigue of the electrical joints and peeling of the sealing resin material due to thermal stress/thermal strain become factors that shorten the life of the power module. That is, countermeasures against thermal stress/thermal strain (collectively referred to as heat countermeasures) in power modules are one of the important technical issues.

On the other hand, in technology for electronically controlling machines and devices, miniaturization of semiconductor devices including power modules is one of the most important issues.

Various research and developments are being carried out in response to the various technical requirements as described above. For example, in Patent Document 1 (Japanese Unexamined Patent Publication No. 2006-179538), the back side of a metalized Si semiconductor chip is soldered to an electrode placed on one side of a ceramic insulating substrate, and the other side of the ceramic insulating substrate is In a semiconductor power module soldered to a base substrate, the semiconductor power module includes a connecting conductor connecting the surface of the Si semiconductor chip and another electrode of the ceramic insulating substrate, and one of the Si semiconductor chip and the ceramic insulating substrate. and a second resin that covers the first resin, and the Young's modulus of the first resin is the Young's modulus of the second resin. The second resin is an epoxy resin having a Young's modulus of 3 GPa to 20 GPa and a linear expansion coefficient of 10×10 ^-6 /°C to 40×10 ^-6 /°C. , a semiconductor power module characterized in that the second resin is sealed by potting or transfer molding is disclosed.

According to Patent Document 1, the combination of resins with two different functions creates a structure that is more resistant to large chips, severe power cycling, and temperature cycling tests, and simultaneously improves the thermal fatigue life and moisture resistance of the solder. It is said that it is possible to provide a semiconductor power module that also protects the element portion.

Patent Document 2 (Japanese Unexamined Patent Publication No. 2007-027261) discloses a plurality of wiring ceramic substrates each having a wiring layer formed on a ceramic substrate, a power semiconductor element mounted on at least one of the wiring layers, and a plurality of wiring ceramic A power module is disclosed that includes a substrate and a sealing resin for molding the power semiconductor element, and a bonding member bonded to the plurality of wiring ceramic substrates.

According to Patent Document 2, by using a plurality of wiring ceramic substrates, it is possible to obtain a transfer mold type power module in which cracking of the ceramic substrate and peeling of the sealing resin are prevented.

Patent Document 3 (JP 2017-152722) discloses a ceramic substrate, a first pattern of a first copper plate layer disposed on the surface of the ceramic substrate, and a first semiconductor disposed on the first pattern. a first columnar connection electrode disposed on the first pattern; an output terminal connected to the first columnar connection electrode; a first columnar electrode disposed on the first semiconductor device; a first diode disposed adjacent to the first semiconductor device on a first pattern; a third columnar electrode disposed on the first diode; and on the first columnar electrode and on the third columnar electrode. a first top plate electrode disposed on the first semiconductor device, the first columnar electrode, the first top plate electrode, and the first columnar electrode. A power module semiconductor device is disclosed, which is characterized in that the thickness of the semiconductor device is approximately the same as the sum of the thicknesses of the solder layer and the solder layer bonded to one top plate electrode.

According to Patent Document 3, it is possible to provide a power module semiconductor device that can reduce the size and weight of a thin power module.

Japanese Patent Application Publication No. 2006-179538 Japanese Patent Application Publication No. 2007-027261 JP 2017-152722 Publication

As mentioned above, the electrification and electronic control of power sources for industrial machinery and vehicles have progressed more and more in recent years, and the demand for higher output power sources has led to even greater demands for higher power power modules. There is. Increasing the power output of power modules is directly linked to an increase in the amount of heat generated during operation, which requires more efficient heat countermeasures than in the past. In addition, the demand for smaller power modules continues to grow stronger.

The present inventors have made it a prerequisite to adopt a double-sided cooling method in which a power semiconductor element is cooled from both sides as a cooling means for heat countermeasures. In order to meet the demand for miniaturization of power modules without interfering with the double-sided cooling method, we considered changing the connection means for signal wiring connected to the signal electrodes of power semiconductor elements. Specifically, instead of the conventional bonding wire connection between a lead frame and a signal electrode, a substrate with built-in signal wiring (hereinafter referred to as a signal line built-in substrate) is used to connect the signal wiring and signal electrode. The policy was to connect directly.

After conducting various studies to find the optimal configuration for realizing a smaller power module, it was discovered that resin sealing was more difficult than expected. Specifically, by using a substrate with built-in signal lines, we faced a new problem: filling the sealing resin material is more difficult than with conventional wire bonding structures, and undesired voids are more likely to remain. The remaining voids pose a problem in ensuring electrical insulation.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a power module that achieves efficient heat countermeasures, miniaturization, and also ensures electrical insulation. There is a particular thing.

One aspect of the present invention is a power module, comprising:
a plurality of power semiconductor elements;
a first input/output board having a first input/output wiring layer formed on one surface of an electrically insulating layer;
a second input/output board having a second input/output wiring layer formed on one surface of the electrically insulating layer;
It has a signal line built-in board made of an electrically insulating material and has a built-in signal line,
A semiconductor element unit is configured by disposing the signal line built-in board on which the plurality of power semiconductor elements are mounted between the first input/output board and the second input/output board, and the semiconductor element unit is sealed. It is sealed with a sealing resin material,
Each of the plurality of power semiconductor elements has a signal electrode and a first input/output electrode formed on one surface, and a second input/output electrode formed on the other surface,
The first input/output wiring layer includes a plurality of first input/output terminal sections corresponding to the plurality of power semiconductor elements, and each of the plurality of first input/output terminal sections is connected to the first input/output wiring. conductive to the signal line and located in each of the plurality of input/output terminal through holes formed in the signal line built-in substrate;
In each of the plurality of power semiconductor elements, the signal electrode is directly connected to the signal wiring, and the first input/output electrode is directly connected to one of the plurality of first input/output terminal parts. , the second input/output electrode is directly connected to the second input/output wiring layer,
The signal line built-in board has a sealing resin flow hole through which the sealing resin material before hardening can flow between the plurality of input/output terminal through holes, and the sealing resin flow hole Filled with resin-blocking material,
The present invention provides a power module characterized by the following.

According to the present invention, the following improvements and changes can be made to the power module described above.
(i) The first input/output wiring layer and the first input/output terminal section are formed of the same metal layer.
(ii) The signal line built-in board is a multilayer circuit board made of low-temperature co-fired ceramics, and its surface is made of a resin material different from the sealing resin material, and the adhesion between the sealing resin material and the signal line built-in board is It has an adhesion-improving layer that improves.
(iii) The sealing resin material is made of epoxy resin, and the different resin material is made of polyamideimide resin or polyimide resin.
(iv) The sealing resin flow hole has an equivalent circle diameter of 1.0 mm or more and a total aperture area of 1.5 mm ² or more.
(v) The thickness of the first input/output wiring layer between the adjacent first input/output terminal parts is thinner than other parts.
(vi) The other surface of the electrically insulating layer of the first input/output board and the other surface of the electrically insulating layer of the second input/output board are exposed from the sealing resin material.
(vii) A heat transfer metal layer is further formed on the other surface of the electrically insulating layer of the first input/output board and on the other surface of the electrically insulating layer of the second input/output board. The heat transfer metal layer is exposed from the sealing resin material.
(viii) A direct connection between the first input/output electrode and the first input/output terminal section, a direct connection between the second input/output electrode and the second input/output wiring layer, and a direct connection between the signal electrode and the signal wiring. The direct connections are made through conductive bonding materials, respectively.
(ix) The first input/output board and the second input/output board are ceramic boards in which the electrically insulating layer is made of ceramic.

According to the present invention, it is possible to provide a power module that achieves efficient heat countermeasures, miniaturization, and ensures electrical insulation.

FIG. 1 is a schematic perspective view showing an example of a power module according to the present invention. FIG. 1B is a schematic plan view of the power module of FIG. 1A. FIG. 1B is a schematic cross-sectional view of the power module of FIG. 1A. FIG. 2 is a schematic plan view showing an example of a signal line built-in substrate used in the present invention. It is a cross-sectional schematic diagram which shows another example of the power module based on this invention. It is a cross-sectional schematic diagram which shows yet another example of the power module based on this invention. FIG. 7 is a schematic plan view showing still another example of the power module according to the present invention. FIG. 7 is a schematic plan view showing still another example of the power module according to the present invention.

Hereinafter, embodiments according to the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to the embodiments discussed here, and can be appropriately combined with known techniques or improved based on known techniques without departing from the technical idea of the invention. . In addition, the same reference numerals may be given to the same members, and redundant explanations may be omitted.

[First embodiment]
FIG. 1A is a schematic perspective view showing an example of a power module according to the present invention, FIG. 1B is a schematic plan view (top surface) of the power module, and FIG. 1C is a schematic cross-sectional view of the power module. .

As shown in FIGS. 1A to 1C, the power module 100 includes four members: a first input/output board 110, a signal line built-in board 130, a power semiconductor element 140, and a second input/output board 120. , these four members are laminated in that order and sealed with a sealing resin material 150. In other words, in this embodiment, the signal line built-in board 130 on which the power semiconductor element 140 is mounted is disposed between the first input/output board 110 and the second input/output board 120 to constitute a semiconductor element unit, and the semiconductor element unit is configured. The element unit is sealed with a sealing resin material. 1A to 1C show an example of a power module in which one signal line built-in board 130 mounts two power semiconductor elements 140. In FIG. 1C, two power semiconductor devices 140 are shown, but since the code leader lines are crowded, codes 141 to 144 for explaining the configuration of the power semiconductor device 140 are used only for the power semiconductor device on the right side of the drawing. It shows. The power semiconductor element on the left side of the drawing also has a similar configuration (a symmetrical configuration in the drawing). In addition, the signal line built-in substrate 130 is formed with structures corresponding to the two power semiconductor elements (signal wiring 132, input/output terminal through holes 133, etc. to be described later), but in FIG. Since the lines are crowded, the numbers 131 to 133 for explaining the structure of the signal line built-in board 130 are shown only on the left side of the drawing. The signal line built-in board 130 has a similar configuration on the left side of the drawing (a symmetrical configuration in the drawing).

Looking in detail, the first input/output board 110 is a board in which a first input/output wiring layer 112 is formed on one surface of an electrically insulating layer 111. 1 input/output terminal section 113 is formed. The first input/output terminal section 113 protrudes from the first input/output wiring layer 112 so as to be located within an input/output terminal section through hole 133, which will be described later. Further, the first input/output terminal section 113 is formed to be perpendicular to the plane of the signal line built-in board 130. The length of the portion of the first input/output terminal section 113 protruding from the first input/output wiring layer 112 is formed to be longer than the thickness of the signal line built-in substrate 130. Furthermore, a heat transfer metal layer 114 is formed on the opposite surface of the electrical insulating layer 111. Note that the first input/output wiring layer 112 may be constructed by joining the first input/output terminal section 113, which is a protrusion, to a plane layer. In other words, the first input/output wiring layer 112 may be composed of two metal layers. Furthermore, the first input/output terminal section 113 may be configured as a via electrode within the input/output terminal section through hole 133 formed in the signal line built-in substrate 130. However, considering contact resistance and the like, it is desirable that the first input/output terminal section 113 be formed of the same metal layer as the first input/output wiring layer 112.

The heat conductive metal layers 214 and 224 are formed of a good conductor (metal with high thermal conductivity, such as Cu, Al, etc.) similar to the first input/output wiring layer 112 and the second input/output wiring layer 122. is preferred. By having the heat transfer metal layers 214 and 224, the heat transferred through the electrical insulation layers 111 and 121 quickly spreads in the in-plane direction of the heat transfer metal layers 214 and 224, thereby further increasing the cooling efficiency of the power module. (i.e. more efficient heat management).

The signal line built-in board 130 is a multilayer circuit board made of an electrically insulating material 131 and in which signal lines 132 are built-in. In the power semiconductor element 140, a first input/output electrode 141 and a signal electrode 143 are formed on one surface of a semiconductor chip 144, and a second input/output electrode 142 is formed on the other surface.

The first input/output terminal section 113 of the first input/output wiring layer 112 penetrates the signal line built-in substrate 130 and is directly connected to the first input/output electrode 141 of the power semiconductor element 140. In other words, the signal line built-in board 130 is formed with an input/output terminal through hole 133 through which the first input/output terminal 113 passes. Note that in this specification, "direct connection" means connection without intervening a bonding wire, for example, connecting the first input/output terminal portion 113 and the first input/output electrode 141 with the conductive bonding material 160 or the like. When connecting. The signal wiring 132 of the signal line built-in substrate 130 is directly connected to the signal electrode 143 of the power semiconductor element 140. The second input/output board 120 is a board in which a second input/output wiring layer 122 is formed on one surface of the electrical insulating layer 121, and is directly connected to the second input/output electrode 142 of the power semiconductor element 140. are doing. Further, a heat transfer metal layer 124 is formed on the opposite surface of the electrical insulating layer 121 from the second input/output wiring layer 122.

From the viewpoint of efficient heat countermeasures for the power module 100, the surfaces of the first input/output board 110 and the second input/output board 120 (in this embodiment, the surfaces of the heat transfer metal layers 114 and 124) are coated with a sealing resin material 150. It is preferable that it be exposed. Although not shown in FIGS. 1A to 1C, since the power module 100 employs a double-sided cooling method, cooling means (for example, heat radiation fins, cooling channels) may be brought into contact with the surfaces of the heat transfer metal layers 114 and 124. is preferred. In other words, in the power module 100, since the heat transfer metal layers 114 and 124 of the first input/output board 110 and the second input/output board 120 are exposed on the outermost surface, it is easy to adopt a double-sided cooling method, and the cooling Another advantage is that there is a high degree of freedom in handling the means.

From various studies by the present inventors, when resin sealing of the power module 100 is performed by transfer molding, an area 150a sandwiched between adjacent first input/output terminal sections 113 (first input/output a region surrounded by the wiring layer 112, the first input/output terminal section 113, and the signal line built-in substrate 130), and a region 150b sandwiched between the adjacent power semiconductor elements 140 (the region surrounded by the second input/output wiring layer 122 and the power semiconductor element 140). It has been found that it is more difficult to fill the sealing resin material in the region (surrounded by the signal line built-in substrate 130) than in other regions (unwanted voids are likely to remain).

Therefore, in the present invention, as shown in FIG. 1C and FIG. It forms 134. FIG. 2 is a schematic plan view showing an example of a signal line built-in substrate used in the present invention. By forming the sealing resin flow hole 134, the sealing resin material 150 before hardening can/easily flow between the region 150a and the region 150b, and it is possible to prevent undesired gaps from remaining.

It is preferable that the sealing resin circulation hole 134 has an equivalent circular diameter of 1.0 mm or more (if the hole is circular, the radius of curvature is 0.5 mm or more), and a total aperture area of 1.5 mm ² or more. As explained in the examples below, when the equivalent circle diameter of the openings is 1.0 mm and the total opening area is 1.5 mm ² , no unwanted air bubbles remain during transfer molding of the sealing resin material 150. We have confirmed that. If the circular equivalent diameter of the openings is less than 1.0 mm or the total opening area is less than 1.5 mm ² , there is a possibility that undesired air bubbles may remain during transfer molding of the sealing resin material 150.

Although FIG. 2 shows an example in which two circular holes are formed, the present invention is not limited thereto. For example, as long as the radius of curvature of the aperture is 0.5 mm or more and the total aperture area is 1.5 mm ² or more, the number of circular holes may be one. In addition, as long as the equivalent circle diameter of the hole is 1.0 mm or more and the total hole area is 1.5 mm ² or more, it may be one or more oval holes or one or more oval holes. good.

Furthermore, from the viewpoint of electrical insulation and heat resistance in the power module 100, a multilayer circuit board with built-in wiring of a highly conductive metal (for example, Ag or Cu) may be used as the signal line built-in board 130. It is particularly preferable to use a low-temperature co-fired ceramic substrate (LTCC substrate) whose main components are Al ₂ O ₃ , SiO ₂ , and SrO and which can be fired simultaneously with the metal of the circuit.

The sealing resin material 150 used in the present invention is not particularly limited, and may be appropriately selected from conventional resin materials in consideration of the usage environment (for example, temperature, humidity) of the power module 100. For example, epoxy resins (phenol novolak type, polyfunctional type, biphenyl type, etc.) having a glass transition temperature of 175° C. or higher can be suitably used. The glass transition temperature is more preferably 200°C or higher.

In addition, from the viewpoint of suppressing thermal stress/thermal strain caused by temperature differences between operating and resting periods, appropriate fillers (e.g., ceramic particles such as SiO ₂ , Al ₂ O ₃ , AlN, BN, etc.) are added to the resin. It is preferable to adjust the thermal expansion coefficient of the sealing resin material 150 by mixing elastomer particles such as gel or rubber. The thermal expansion coefficient to be adjusted is preferably 3 to 23 ppm/K, more preferably 7 to 20 ppm/K.

Here, when using an LTCC substrate as the signal line built-in substrate 130, it is better to consider the adhesion between the LTCC substrate and the epoxy resin sealing resin material 150. That is, the wettability between the LTCC substrate and the epoxy resin sealing resin material 150 is not very good (adhesion is not very good).

Therefore, when an LTCC substrate is used as the signal line built-in substrate 130, it is preferable to form an adhesion improving layer 135 made of resin on the surface of the signal line built-in substrate 130. As the resin material constituting the adhesion improving layer 135, polyamide-imide resin or polyimide resin can be suitably used. There is no particular limitation on the method of forming the adhesion improving layer 135, and conventional methods (for example, coating and baking the resin) may be used as appropriate. By forming the adhesion improving layer 135, the possibility of peeling occurring at the interface between the LTCC substrate and the sealing resin material 150 due to thermal stress/thermal strain of the power module 100 can be reduced.

The first input/output board 110 and the second input/output board 120 used in the present invention are not particularly limited, and may be appropriately selected from conventional boards in consideration of the usage environment (for example, temperature, humidity) of the power module 100. . For example, a ceramic substrate in which the electrical insulating layers 111 and 121 are made of ceramic can be suitably used. As the electrically insulating layers 111 and 121, it is preferable to use Si ₃ N ₄ , AlN, Al ₂ O ₃ or the like from the viewpoint of electrical insulation and thermal conductivity.

As described above, in the power module 100, the first input/output terminal section 113 of the first input/output wiring layer 112 and the first input/output electrode 141 of the power semiconductor element 140 are directly connected, and the signal line built-in substrate The signal wiring 132 of 130 and the signal electrode 143 of the power semiconductor element 140 are directly connected, and the second input/output wiring layer 122 of the second input/output board 120 and the second input/output electrode 142 of the power semiconductor element 140 are directly connected. are directly connected.

From the viewpoint of connection stability, these direct connections are preferably made through conductive bonding material 160, respectively. The conductive bonding material 160 to be used is not particularly limited, and may be appropriately selected from conventional bonding materials in consideration of the usage environment (for example, temperature, humidity) of the power module 100. For example, solder, metal nanoparticles, conductive low melting point glass, etc. can be suitably used.

[Second embodiment]
FIG. 3 is a schematic cross-sectional view showing another example of the power module according to the present invention. As shown in FIG. 3, the power module 200 of the second embodiment has a first input/output board 210 and a second input/output board 220 on the other surface of the electrically insulating layers 111 and 121 (first input/output wiring). This power module 100 differs from the power module 100 of the first embodiment in that it does not have a heat conductive metal layer (on the surface opposite to the layer 112 and the second input/output wiring layer 122), but is otherwise the same as the power module 100 of the first embodiment.

The structure is such that the electrical insulating layers 111 and 121 are exposed from the sealing resin material 150. As in the first embodiment, cooling means (for example, radiation fins, cooling channels) can be brought into contact with the surfaces of the electrically insulating layers 111 and 121 to efficiently perform cooling.

[Third embodiment]
FIG. 4 is a schematic cross-sectional view showing still another example of the power module according to the present invention. As shown in FIG. 4, the power module 300 of the third embodiment has first input/output wiring between adjacent first input/output terminal sections 113 in the first input/output wiring layer 312 of the first input/output board 310. This power module 100 differs from the power module 100 of the first embodiment in that the thickness of the layer 312 is thinner than the other parts, and the other parts are the same.

In other words, the region 150c sandwiched between the adjacent first input/output terminal sections 113 (the region surrounded by the first input/output wiring layer 312, the first input/output terminal section 113, and the signal line built-in board 130) is It will be larger/wider than the feature area 150a (see FIG. 1C). As a result, the sealing resin material 150 before hardening can easily flow in and flow, and it is possible to more efficiently prevent undesired voids from remaining. This contributes to ensuring electrical insulation and improving long-term reliability.

[Fourth embodiment]
FIG. 5 is a schematic plan view showing still another example of the power module according to the present invention. As shown in FIG. 5, the power module 400 of the fourth embodiment is different from the first to third embodiments in that one signal line built-in board 430 mounts four power semiconductor elements 140. Unlike modules 100 to 300, the others are the same. By increasing the number of power semiconductor elements 140 mounted, it is possible to contribute to miniaturization while responding to increased power.

[Fifth embodiment]
FIG. 6 is a schematic plan view showing still another example of the power module according to the present invention. As shown in FIG. 6, the power module 500 of the fifth embodiment is similar to the fourth embodiment in that two signal line built-in substrates 430 on which four power semiconductor elements 140 are mounted are sealed with resin. This power module 400 is different from the power module 400 shown in FIG. The fifth embodiment can contribute to higher power consumption and smaller size than the fourth embodiment.

The present invention will be explained in more detail below through various experiments. However, the present invention is not limited to these experiments.

[Experiment 1]
(Production of power module of Example 1)
As the power module of Example 1, a power module corresponding to the first embodiment was manufactured. Two SiC-MOSFET chips were prepared as power semiconductor elements, an LTCC board with built-in signal wiring was prepared as the signal line built-in board, and Si ₃ N ₄ boards were used as the first input/output board and the second input/output board. A ceramic substrate was prepared, on one surface of which a first input/output wiring layer and a second input/output wiring layer made of copper were formed. The LTCC board has input/output terminal through holes and sealing resin flow holes formed in advance. Two circular holes are formed as sealing resin flow holes, each having a radius of curvature of 0.5 mm and a total opening area of about 1.5 mm ² .

First, an adhesion improving layer was formed on the surface of the LTCC substrate. An N-methyl-2-pyrrolidone solution of polyamideimide resin was prepared, and after masking the input/output terminals, the LTCC substrate was immersed in the solution. After removing the immersed LTCC substrate from the solution, it was baked (held at 100°C for 30 minutes, then held at 200°C for 1 hour) to form an adhesion-enhancing layer (3 μm thick) made of polyamide-imide resin. A board with built-in signal lines was fabricated.

Each member is stacked in the order of the first input/output board, the signal line built-in board, the power semiconductor element, and the second input/output board, and the first input/output terminal part of the first input/output wiring layer and the power semiconductor element are stacked. between the first input/output electrode, between the signal wiring of the signal line built-in board and the signal electrode of the power semiconductor element, and between the second input/output electrode of the power semiconductor element and the second input/output wiring layer of the second input/output board. They were directly bonded using lead-free solder (conductive bonding material). The resulting assembly of four members will be referred to as a semiconductor element unit.

Next, the obtained semiconductor element unit was resin-sealed using a transfer molding device. Epoxy resin (glass transition temperature 205°C, linear expansion coefficient 16 ppm/K, elastic modulus 11 GPa) was used as the sealing resin material, and appropriate molding conditions (mold temperature 180°C, mold pressure 6.9 MPa, molding time 180 seconds) were used. ) was used for transfer molding. Thereafter, the sealing resin material was heat-cured (held at 175° C. for 6 hours) to complete the power module of Example 1.

[Experiment 2]
(Production of power module of Example 2)
As the power module of Example 2, a power module corresponding to the fourth embodiment was manufactured. Four SiC-MOSFET chips were prepared as power semiconductor elements. For the signal line built-in board, an LTCC board was prepared in which a sealing resin flow hole was formed between adjacent input/output terminal through holes and at a central position surrounded by four input/output terminal through holes. The first input/output board has a feature of the third embodiment (the thickness of the first input/output wiring layer in the area sandwiched between adjacent first input/output terminal parts is thinner than in other areas (here, the thickness is thinner than the other area). A ceramic substrate was prepared that had the following characteristics: Furthermore, as the second input/output board, a ceramic board similar to that used in Experiment 1 was prepared.

The other procedures were the same as in Experiment 1 to complete the power module of Example 2.

[Experiment 3]
(Production of power modules of Comparative Examples 1 and 2)
The power modules of Comparative Examples 1 and 2 were prepared in the same manner as Experiments 1 and 2, except that an LTCC board without sealing resin flow holes (input/output terminal through holes were formed) was used as the signal line built-in board. was created.

[Experiment 4]
(Confirmation of filling state of sealing resin material in Examples 1 and 2 and Comparative Examples 1 and 2)
The power modules of Examples 1 to 2 and Comparative Examples 1 to 2 produced in Experiments 1 to 3 were cut using a diamond saw, and the filling state of the sealing resin material (especially the adjacent first input/output terminals) was cut using a diamond saw. The filling state of the sealing resin material in the sandwiched region, region 150a in FIG. 1C, and region 150c in FIG. 4) was observed with a microscope. As a result, it was confirmed that the power modules of Examples 1 and 2 were completely filled with no undesired voids remaining. On the other hand, in the power modules of Comparative Examples 1 and 2, it was confirmed that undesired voids (bubbles) remained in the region sandwiched between adjacent first input/output terminal portions.

The embodiments and experimental examples described above are explained to help understand the present invention, and the present invention is not limited to the specific configurations described. For example, it is possible to replace a part of the configuration of the embodiment with a configuration that is common technical knowledge of a person skilled in the art, or it is also possible to add a configuration that is common technical knowledge of a person skilled in the art to the configuration of the embodiment. That is, the present invention allows deletion, replacement, and addition of other configurations to some of the configurations of the embodiments and experimental examples in this specification without departing from the technical idea of the invention. It is possible.

100, 200, 300, 400, 500...power module,
110, 210, 310...first input/output board, 111...electrical insulating layer,
112, 312...first input/output wiring layer, 113...first input/output terminal section, 214...heat transfer metal layer,
120, 220...second input/output board, 121...electrical insulating layer,
122...Second input/output wiring layer, 224...Heat transfer metal layer,
130, 430... Signal line built-in board, 131... Electrical insulation material, 132... Signal wiring,
133...Input/output terminal part through hole, 134...Sealing resin distribution hole, 135...adhesion improving layer,
140...power semiconductor element,
141...first input/output electrode, 142...second input/output electrode, 143...signal electrode, 144...semiconductor chip,
150...Sealing resin material,
150a, 150c...A region sandwiched between adjacent first input/output terminal parts,
150b...A region sandwiched between adjacent power semiconductor elements,
160...Conductive bonding material.

Claims (10)

A power module,
a plurality of power semiconductor elements;
a first input/output board having a first input/output wiring layer formed on one surface of an electrically insulating layer;
a second input/output board having a second input/output wiring layer formed on one surface of the electrically insulating layer;
It has a signal line built-in board made of an electrically insulating material and has a built-in signal line,
A semiconductor element unit is configured by disposing the signal line built-in board on which the plurality of power semiconductor elements are mounted between the first input/output board and the second input/output board, and the semiconductor element unit is sealed. It is sealed with a sealing resin material,
Each of the plurality of power semiconductor elements has a signal electrode and a first input/output electrode formed on one surface, and a second input/output electrode formed on the other surface,
The first input/output wiring layer includes a plurality of first input/output terminal sections corresponding to the plurality of power semiconductor elements, and each of the plurality of first input/output terminal sections is connected to the first input/output wiring. conductive to the signal line and located in each of the plurality of input/output terminal through holes formed in the signal line built-in substrate;
In each of the plurality of power semiconductor elements, the signal electrode is directly connected to the signal wiring, and the first input/output electrode is directly connected to one of the plurality of first input/output terminal parts. , the second input/output electrode is directly connected to the second input/output wiring layer,
The signal line built-in board has a sealing resin flow hole through which the sealing resin material before hardening can flow between the plurality of input/output terminal through holes, and the sealing resin flow hole Filled with resin-blocking material,
A power module characterized by: The power module according to claim 1,
the first input/output wiring layer and the first input/output terminal section are formed of the same metal layer;
A power module characterized by: The power module according to claim 1 or 2,
The signal line built-in board is a multilayer circuit board made of low-temperature co-fired ceramics, and its surface is made of a resin material different from the sealing resin material to improve the adhesion between the sealing resin material and the signal line built-in board. Has an adhesion improving layer,
A power module characterized by: The power module according to claim 3,
The sealing resin material is made of epoxy resin,
The different resin material is made of polyamideimide resin or polyimide resin,
A power module characterized by: The power module according to any one of claims 1 to 4,
The sealing resin flow hole has an equivalent circle diameter of 1.0 mm or more and a total aperture area of 1.5 mm ² or more,
A power module characterized by: The power module according to any one of claims 1 to 5,
The thickness of the first input/output wiring layer between the adjacent first input/output terminal parts is thinner than other parts.
A power module characterized by: The power module according to any one of claims 1 to 6,
The other surface of the electrically insulating layer of the first input/output board and the other surface of the electrically insulating layer of the second input/output board are exposed from the sealing resin material.
A power module characterized by: The power module according to any one of claims 1 to 6,
A heat transfer metal layer is further formed on the other surface of the electrically insulating layer of the first input/output board and on the other surface of the electrically insulating layer of the second input/output board,
the heat transfer metal layer is exposed from the sealing resin material;
A power module characterized by: The power module according to any one of claims 1 to 8,
A direct connection between the first input/output electrode and the first input/output terminal section, a direct connection between the second input/output electrode and the second input/output wiring layer, and a direct connection between the signal electrode and the signal wiring. are made through conductive bonding materials, respectively.
A power module characterized by: The power module according to any one of claims 1 to 9,
The first input/output board and the second input/output board are ceramic boards in which the electrical insulating layer is made of ceramic.
A power module characterized by:

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