Semiconductor device and insulating member

Abstract

A semiconductor device according to the present invention is provided with: a first conductor member to which a switching element is connected; a second conductor member to which a switching element is connected; a heat dissipation member which is arranged so as to face the first and second conductor members that are arranged side by side; and an insulating member which comprises a first intermediate conductor that faces the first conductor member, a second intermediate conductor that faces the second conductor member, and an electrical insulation layer that internally contains the first and second intermediate conductors, and which is arranged between the heat dissipation member and the first and second conductor members that are arranged side by side. The electrical insulation layer comprises: a first insulating layer in which the first intermediate conductor is arranged; a second insulating layer in which the second intermediate conductor is arranged; and a third insulating layer which is interposed between the first insulating layer and the second insulating layer.

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device and an insulating member used in the semiconductor device. [Background technology]

[0002] In a power module, an insulating layer such as an insulating sheet is provided between a lead frame on which a power semiconductor element is arranged and a heat dissipation wall of a module case. The heat dissipation wall is formed from a conductive material and is grounded to GND to stabilize the voltage. The power module described in Patent Document 1 employs a structure in which intermediate conductors are disposed in the insulating layers facing each other on the upper and lower arm lead frames, thereby dividing the voltage applied to the insulating layers. When assembling the power module, two intermediate conductors are sandwiched between two insulating sheets, and the insulating sheets with the intermediate conductors sandwiched between them are disposed between each lead frame on the upper and lower arms and the heat dissipation wall. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent No. 6200871 Summary of the Invention [Problem to be solved by the invention]

[0004] However, to ensure the voltage division function, it is preferable to place the intermediate conductor so that it faces the entire lead frame, and the two intermediate conductors facing the lead frames of the upper and lower arms are placed side by side with a small gap between them. When placing the intermediate conductors between the insulating sheets, they need to be aligned so that they do not come into contact with each other, which reduces productivity in the assembly process. [Means for solving the problem]

[0005] The present invention 1stThe semiconductor device according to the aspect includes a first conductor member to which an upper arm switching element of an inverter circuit is connected, a second conductor member to which a lower arm switching element of the inverter circuit is connected, a heat dissipation member arranged opposite the juxtaposed first and second conductor members, a first intermediate conductor facing the first conductor member, a second intermediate conductor facing the second conductor member, and an insulating member having an electrical insulating layer containing the first and second intermediate conductors and arranged between the juxtaposed first and second conductor members and the heat dissipation member, wherein the electrical insulating layer has a first insulating layer in which the first intermediate conductor is arranged, a second insulating layer in which the second intermediate conductor is arranged, and a third insulating layer interposed between the first insulating layer and the second insulating layer. The first and second intermediate conductors are set in either a first arrangement state in which the distance from the second conductive member to the surface of the second intermediate conductor facing the heat dissipation member side is set to be smaller than the distance from the first conductive member to the surface of the first intermediate conductor facing the conductor member side, or a second arrangement state in which the distance from the second conductive member to the surface of the second intermediate conductor facing the conductor member side is set to be larger than the distance from the first conductive member to the surface of the first intermediate conductor facing the heat dissipation member side. . A semiconductor device according to a second aspect of the present invention includes a first conductor member to which an upper arm switching element of an inverter circuit is connected, a second conductor member to which a lower arm switching element of the inverter circuit is connected, a heat dissipation member arranged opposite the juxtaposed first and second conductor members, a first intermediate conductor facing the first conductor member, a second intermediate conductor facing the second conductor member, and an electrically insulating layer containing the first and second intermediate conductors, and an insulating member disposed between the first and second intermediate conductors, wherein the electrically insulating layer has a first insulating layer on which the first intermediate conductor is disposed, a second insulating layer on which the second intermediate conductor is disposed, and a third insulating layer interposed between the first insulating layer and the second insulating layer, and the insulating member comprises a first insulating sheet formed of an electrically insulating material and having an area facing the first and second intermediate conductors, wherein the first intermediate conductor is laminated on one side of the first insulating sheet and the second intermediate conductor is laminated on the other side of the first insulating sheet. [Effects of the Invention]

[0006] According to the present invention, contact between intermediate conductors can be prevented, and productivity can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a circuit diagram illustrating the circuit configuration of a semiconductor device according to this embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the power module. [Figure 3] FIG. 3 is an exploded perspective view of the circuit mold body. [Figure 4] FIG. 4 is a cross-sectional view showing a transverse section (xy cross section) of the power module. [Figure 5] FIG. 5 is a diagram illustrating the arrangement of intermediate conductors in the first arrangement state. [Figure 6] FIG. 6 is a diagram illustrating the arrangement of intermediate conductors in the second arrangement state. [Figure 7] FIG. 7 is a plan view of the heat dissipation sheet. [Figure 8] FIG. 8 is a cross-sectional view taken along line AA in FIG. [Figure 9]FIG. 9 is a diagram showing an example of a manufacturing procedure for a heat dissipation sheet. [Figure 10] FIG. 10 is a diagram showing a heat dissipation sheet provided on one surface of the circuit molded body. [Figure 11] FIG. 11 is a diagram showing the case where d5=0 in FIG. [Figure 12] FIG. 12 is a diagram showing the configuration of FIG. 11 in which the heat dissipation sheet is shifted to the right in the drawing. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of a semiconductor device according to the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. Furthermore, in the following description, identical or similar elements and processes are given the same reference numerals, and duplicate explanations may be omitted. Note that the content described below merely shows an example of an embodiment of the present invention, and the present invention is not limited to the following embodiment, and can be implemented in various other forms.

[0009] FIG. 1 is a circuit diagram illustrating the circuit configuration of a semiconductor device according to this embodiment. The semiconductor device according to this embodiment is provided in an inverter circuit of a power conversion device mounted on, for example, an electric vehicle or a hybrid vehicle, and is also called a power module. Hereinafter, the term "power module" will be used instead of "semiconductor device." The power conversion device performs power conversion between a DC power source and a motor generator (for example, a three-phase AC rotating electric machine) for vehicle operation. The power conversion device includes a smoothing capacitor and an inverter circuit serving as a power converter. The inverter circuit converts input DC power into three-phase AC power of a predetermined frequency and outputs it to the motor. Conversely, it converts AC current generated by the generator into DC current and outputs it. The inverter circuit includes, for example, three-phase power modules. FIG. 1 shows a circuit diagram of a power module 100 for one phase.

[0010] The circuit of the power module 100 is composed of an upper arm 100U and a lower arm 100L connected in series. The upper arm 100U includes a power semiconductor element 303U and a diode 304U. The lower arm 100L includes a power semiconductor element 303L and a diode 304L. The power semiconductor elements 303U, 303L are composed of, for example, an insulated gate bipolar transistor (IGBT) or an FET. The power semiconductor element 303U of the upper arm 100U is on / off controlled by a control signal input to an upper arm control terminal 300U. Similarly, the power semiconductor element 303L of the lower arm 100L is on / off controlled by a control signal input to a lower arm control terminal 300L.

[0011] The external connection P terminal 300E of the upper arm 100U is connected to a high-potential power line of a DC power supply, and the external connection N terminal 300D of the lower arm 100L is connected to a low-potential power line of the DC power supply. An external connection AC terminal 300C is provided at the connection point between the upper arm 100U and the lower arm 100L, and AC current is output from the external connection AC terminal 300C to an external device (e.g., a motor). A capacitor or the like is connected to the DC power supply line in parallel with the upper and lower arms 100U and 100L.

[0012] FIG. 2 is an exploded perspective view of the power module 100. The power module 100 is composed of a circuit molded body 101, a heat dissipation sheet 210, and a case 200. The power semiconductor elements 303U and 303L and diodes 304U and 304L shown in FIG. 1 are provided in the circuit molded body 101, and are sealed with a sealing member 102 made of an electrically insulating material. The case 200 is composed of a frame body 202 and two heat dissipation members 201. Pin fins 201A are formed on the outer surface of the heat dissipation member 201. The heat dissipation member 201 is joined to the frame body 202 in a watertight manner. For example, the heat dissipation member 201 is joined to the frame body 202 by friction stir welding (FSW) or the like.

[0013] The circuit molded body 101 is housed in a case 200, and a heat dissipation sheet 210 is disposed between the circuit molded body 101 and the heat dissipation member 201. The heat dissipation sheet 210 is formed of an electrically insulating material and has an intermediate conductor provided therein, as described below. The heat dissipation sheet 210 is adhered to the circuit molded body 101 and the heat dissipation member 201 without any gaps. The heat dissipation sheet 210 is formed, for example, of a resin with high electrical insulation, adhesiveness, and thermal conductivity, and has the function of electrically insulating the circuit molded body 101 and the heat dissipation member 201 and the function of dissipating heat from the circuit molded body 101 to the heat dissipation member 201. The gaps within the case 200 are filled with an electrically insulating resin and sealed.

[0014] FIG. 3 is an exploded perspective view of the circuit molded body 101. The sealing member 102 is not shown. The power semiconductor elements 303U, 303L and the diodes 304U, 304L are plate-shaped elements having connection terminals formed on both the front and back surfaces. The power semiconductor element 303U and the diode 304U of the upper arm 100U are sandwiched between the AC lead frame 302, which is a conductive member, and the upper arm base 300B, and are electrically connected thereto. Similarly, the power semiconductor element 303L and the diode 304L of the lower arm 100L are sandwiched between the N lead frame 301, which is a conductive member, and the lower arm base 300A, and are electrically connected thereto. The connections are made by soldering or the like.

[0015] AC lead frame 302 is formed with protrusion 302A to which power semiconductor element 303U is connected, protrusion 302B to which diode 304U is connected, and AC connection portion 302C. N lead frame 301 is formed with protrusion 301A to which power semiconductor element 303L is connected, protrusion 301B to which diode 304L is connected, and N connection portion 301C. Protrusions 301A, 301B, 302A, and 302B have high flatness accuracy.

[0016] The upper arm base 300B has an external connection P terminal 300E. The lower arm base 300A has an external connection AC terminal 300C. The AC connection portion 302C of the AC lead frame 302 is electrically connected to the lower arm base 300A by soldering. The N connection portion 301C of the N lead frame 301 is electrically connected to the external connection N terminal 300D by soldering. The upper arm control terminal 300U and the lower arm control terminal 300L are electrically connected to the control electrodes of the corresponding power semiconductor elements 303U, 303L, respectively, by wire bonding or the like.

[0017] 4 is a cross-sectional view showing a transverse section (xy cross section) of the power module 100. In the circuit molded body 101, the power semiconductor elements 303U and 303L, the diodes 304U and 304L, the AC lead frame 302, the N lead frame 301, the upper arm base 300B, and the lower arm base 300A are sealed with a sealing member 102. Note that the surfaces of the N lead frame 301, the AC lead frame 302, the lower arm base 300A, and the upper arm base 300B, which are conductive members, that face the heat dissipation member 201 are exposed from the sealing member 102. A heat dissipation sheet 210 is disposed between the circuit molded body 101 and the heat dissipation member 201. Both sides of the heat dissipation sheet 210 are tightly bonded to the circuit molded body 101 and the heat dissipation member 201 with adhesive, grease, or the like. The gaps between the case 200 and the circuit molded body 101 and heat dissipation sheet 210 are filled with sealing resin 205 without leaving any gaps.

[0018] Although not shown, the case 200 of the power module 100 in Fig. 4 is placed in the cooling water channel of the inverter body. Cooling water flows through the pin fins 201A of the heat dissipation member 201, and heat generated in the power module 100 is dissipated from the heat dissipation member 201 to the cooling water.

[0019] An alternating current flows through lower arm base 300A having external connection AC terminal 300C and AC lead frame 302 connected to lower arm base 300A. On the other hand, a direct current flows through upper arm base 300B having external connection P terminal 300E and N lead frame 301 connected to external connection N terminal 300D.

[0020] If an air layer is formed due to peeling between the conductive members N lead frame 301, lower arm base 300A, AC lead frame 302, and upper arm base 300B and heat dissipation sheet 210, or if an air layer such as a void is formed inside heat dissipation sheet 210, corona discharge is likely to occur when high voltage is applied. If corona discharge occurs, heat dissipation sheet 210, which is made of a resin material, deteriorates and its insulation durability decreases significantly. For this reason, intermediate conductors 211 (211A, 211B) are provided in heat dissipation sheet 210 to divide the voltage between the conductive members and heat dissipation member 201.

[0021] Incidentally, corona discharge is more likely to occur on the side of lower arm base 300A and AC lead frame 302, where AC current flows, than on the side of upper arm base 300B and N lead frame 301, where DC current flows. Therefore, the position of intermediate conductor 211 in heat dissipation sheet 210 is biased toward lower arm base 300A and AC lead frame 302 so that the partial voltage between intermediate conductor 211 and lower arm base 300A and AC lead frame 302 is smaller than the partial voltage between intermediate conductor 211 and heat dissipation member 201.

[0022] FIG. 5 is a diagram illustrating the arrangement of the intermediate conductors 211 (211A, 211B) relative to the lower arm base 300A and the upper arm base 300B. To effectively divide the voltage, the intermediate conductor 211 must face at least the entire conductive member. Furthermore, considering the possibility of misalignment of the heat dissipation sheet 210 during assembly, it is preferable for the intermediate conductor 211 to have an area larger than the opposing region of the conductive member. In the conventional power module described in Patent Document 1, the two intermediate conductors 211A, 211B are arranged side by side on the same plane, which may result in contact between the intermediate conductors due to misalignment. Therefore, to prevent the intermediate conductors from contacting each other, i.e., to prevent the distance d5 from becoming d5<0, it was necessary to strictly control the size and positional accuracy of the intermediate conductors 211.

[0023] Therefore, in this embodiment, the intermediate conductors 211A and 211B are arranged as follows to prevent contact between them. The main points of the arrangement are as follows. As shown in FIG. 5 , the heat dissipation sheet 210 includes intermediate conductors 211A and 211B and an electrical insulating layer 212 that contains the intermediate conductors 211A and 211B. The intermediate conductor 211A is arranged in an area facing the lower arm base 300A, and the intermediate conductor 211B is arranged in an area facing the upper arm base 300B. The electrical insulating layer 212 includes a first insulating layer L1 on which the intermediate conductor 211B is arranged, a second insulating layer L2 on which the intermediate conductor 211A is arranged, and a third insulating layer L3 interposed between the first insulating layer L1 and the second insulating layer L2.

[0024] In the heat dissipation sheet 210 described above, a third insulating layer L3 is interposed between the intermediate conductor 211A and the intermediate conductor 211B. Therefore, even when a part of the intermediate conductors 211A and 211B appears to be displaced so as to overlap when the intermediate conductors 211A and 211B are viewed in a projection from the heat dissipation member 201 toward the conductor members (lower arm base 300A and upper arm base 300B), there is no possibility that the intermediate conductors 211A and 211B come into contact with each other. Further, while preventing the intermediate conductors 211A and 211B from contacting each other, the size (area) of the intermediate conductors 211A and 211B can be made as large as possible, and the voltage division function by the intermediate conductors 211A and 211B can be sufficiently exhibited.

[0025] In the above-described key points of the arrangement setting, the arrangement configuration of the intermediate conductors 211A and 211B has been qualitatively described. Hereinafter, the arrangement setting of the intermediate conductors 211A and 211B will be quantitatively described using the distances between the intermediate conductors 211A and 211B and the conductor members facing them. Although a very thin conductor plate such as a copper foil may be used for the intermediate conductors 211A and 211B, here, assuming that the thicknesses of the intermediate conductors 211A and 211B are t2 and t1 as shown in FIG. 5, the distance setting will be described.

[0026] In FIG. 5, t0 is the thickness of the heat dissipation sheet 210. d1 and d3 are the distances from the upper arm base 300B (conductor member) to the conductor member side facing surface and the heat dissipation member side facing surface of the intermediate conductor 211B. d2 and d4 are the distances from the lower arm base 300A (conductor member) to the conductor member side facing surface and the heat dissipation member side facing surface of the intermediate conductor 211A. d5 is the interval in the x direction between the intermediate conductor 211A and the intermediate conductor 211B.

[0027] As shown in FIG. 5, when d2 < d1 such that the intermediate conductor 211A is closer to the conductor member (lower arm base 300A), d4 < d1, and the distance d4 from the lower arm base 300A to the heat dissipation member side facing surface of the intermediate conductor 211A is set to be smaller than the distance d1 from the upper arm base 300B to the conductor member side facing surface of the intermediate conductor 211B. This will be referred to as the first arrangement state.

[0028] On the other hand, contrary to the case of FIG. 5, when d1 < d2 such that the intermediate conductor 211B is closer to the conductor member (upper arm base 300B), the distance d2 from the lower arm base 300A to the conductor member side facing surface of the intermediate conductor 211A is set to be larger than the distance d3 from the upper arm base 300B to the heat dissipation member side facing surface of the intermediate conductor 211B, such as d2 > d3. This is referred to as the second arrangement state. By setting it to the first arrangement state or the second arrangement state in this way, it is possible to prevent the intermediate conductors 211A and 211B in the heat dissipation sheet 210 from coming into contact due to misalignment or the like.

[0029] When t1 = t2, the arrangement condition in the case of FIG. 5 is expressed by the following formula (1) using d1, d2, and t1. d2 < d1 - t1 …(1) Conversely, when the intermediate conductor 211B is closer to the conductor member (upper arm base 300B), the arrangement condition for preventing contact becomes the following formula (2) instead of formula (1). d1 < d2 - t1 …(2)

[0030] FIG. 6 is a diagram showing the arrangement of the intermediate conductors 211A and 211B on the N lead frame 301 and the AC lead frame 302 sides. The same applies to the intermediate conductors 211A and 211B on the N lead frame 301 and the AC lead frame 302 sides. By setting it to the first arrangement state or the second arrangement state described above, it is possible to prevent the intermediate conductors 211A and 211B from contacting each other in the heat dissipation sheet 210. FIG. 6 shows the second arrangement state. That is, in the case where d1 < d2 such that the intermediate conductor 211B is closer to the conductor member (AC lead frame 302), the distance d2 from the N lead frame 301 to the conductor member side facing surface of the intermediate conductor 211A is set to be larger than the distance d3 from the AC lead frame 302 to the heat dissipation member side facing surface of the intermediate conductor 211B, such as d2 > d3.

[0031] Incidentally, as described above, corona discharge is more likely to occur on the lower arm base 300A and the AC lead frame 302 sides where alternating current flows than on the upper arm base 300B and the N lead frame 301 sides where direct current flows. Therefore, as in the first arrangement state shown in FIG. 5, it is preferable to arrange the intermediate conductor 211A on the lower arm base 300A side closer to the conductor member (d2 < d1). On the other hand, in the case of the N lead frame 301 and the AC lead frame 302 sides shown in FIG. 6, since alternating current flows through the AC lead frame 302, it is preferable to adopt the second arrangement state shown in FIG. 6 where d1 < d2.

[0032] Furthermore, in order to suppress the occurrence of corona discharge as much as possible, it is preferable that the potential difference between the intermediate conductor 211A and the lower arm base 300A (conductor member) through which alternating current flows is smaller than the potential difference between the heat dissipation member 201 and the intermediate conductor 211A. That is, in addition to the above-described arrangement conditions, the intermediate conductor 211A is arranged so as to be biased toward the lower arm base 300A side where alternating current flows rather than the center of the heat dissipation sheet 210 so as to satisfy the following formula (3). d2 < (t0 - t1) / 2 …(3)

[0033] 7 and 8 are diagrams showing an example of a heat dissipation sheet 210. While FIGS. 5 and 6 illustrate an example in which the electrical insulating layer 212 of the heat dissipation sheet 210 is molded with an insulating resin, FIGS. 7 and 8 illustrate a case in which the electrical insulating layer 212 is formed from multiple insulating sheets. FIG. 7 is a plan view of the heat dissipation sheet 210, and FIG. 8 is a cross-sectional view taken along line AA in FIG. 7. As shown in FIG. 7, substantially rectangular intermediate conductors 211A and 211B are provided inside the heat dissipation sheet 210. As shown in the cross-sectional view taken along line AA in FIG. 8, the electrical insulating layer 212 of the heat dissipation sheet 210 has a structure in which three insulating sheets 213A, 213B, and 213C are stacked in layers. The insulating sheets 213A, 213B, and 213C are formed from a resin-based member of the same material and have the same thickness t3 and shape. Intermediate conductor 211A is sandwiched between insulating sheets 213B and 213C, and intermediate conductor 211B is sandwiched between insulating sheets 213A and 213B. Intermediate conductors 211A and 211B are formed of a conductive material such as copper foil, for example.

[0034] FIG. 9 shows an example of a manufacturing procedure for the heat dissipation sheet 210. In step 1, an intermediate conductor 211 is bonded to one surface of the insulating sheet 213 so as to cover the opposing region R of the conductor member, thereby forming a sheet with intermediate conductor 214. In step 2, sheets with intermediate conductor 214 are bonded to both the front and back surfaces of the insulating sheet 213 (213B), with the intermediate conductors 211 arranged so that the left and right sides are reversed. That is, the sheet with intermediate conductor 214 is bonded to the upper surface of the insulating sheet 213 (213B) in the figure so that the intermediate conductor 211 (211A) faces the region on the left side of the insulating sheet 213 (213B) in the figure. On the other hand, the sheet with intermediate conductor 214 is bonded to the lower surface of the insulating sheet 213 (213B) in the figure so that the intermediate conductor 211 (211B) faces the region on the right side of the insulating sheet 213 (213B) in the figure. Note that the sheets are pressure-bonded to prevent voids from forming in the bonding area. Furthermore, if the insulating sheet has adhesive properties, the sheets may be integrated using the adhesive properties without using adhesive.

[0035] Alternatively, intermediate conductors 211A and 211B may be fixed to the front and back surfaces of insulating sheet 213B to form intermediate conductor-equipped sheet 214A. In this case, heat dissipation sheet 210 is formed by laminating insulating sheets 213A and 213B on both the front and back surfaces of intermediate conductor-equipped sheet 214A to which intermediate conductors 211A and 211B are fixed.

[0036] Here, the three insulating sheets 213A, 213B, and 213C are made of the same shape, thickness, and material. As described above, the stacked insulating sheets 213A, 213B, and 213C are pressure-bonded together so that no gaps are formed in the bonded areas. Therefore, even if the thickness is t3, for example, the sheet areas above and below the intermediate conductors 211A and 211B are compressed, resulting in a thickness slightly thinner than t3, as shown in FIG. 8. The two intermediate conductors 211A and 211B are also made of the same shape, thickness, and material (e.g., copper foil).

[0037] 8 and 9, components can be standardized, improving productivity. Note that the insulating sheet 213B disposed between the two intermediate conductors 211A and 211B has the function of preventing contact between the intermediate conductors 211A and 211B, and therefore, if it is necessary to reduce thermal resistance, the insulating sheet 213B may be thinner than the other insulating sheets 213A and 213C.

[0038] 8 is disposed between the lower arm base 300A and the upper arm base 300B in FIG. 4 and the heat dissipation member 201, the lower surface of the heat dissipation sheet 210 in the figure is disposed facing the heat dissipation member 201. On the other hand, when the heat dissipation sheet 210 is disposed between the N lead frame 301 and the AC lead frame 302 in FIG. 4 and the heat dissipation member 201, the upper surface of the heat dissipation sheet 210 in the figure in FIG. 8 may be disposed facing the heat dissipation member 201.

[0039] 7 and 8, the intermediate conductors 211A and 211B are disposed between different layers of the three insulating sheets 213A to 213C. Therefore, even if there appears to be an overlapping region between the intermediate conductors 211A and 211B when viewed projected in the y direction in FIG. 8, the insulating sheet 213B between the intermediate conductors 211A and 211B prevents the intermediate conductors 211A and 211B from coming into contact with each other due to misalignment of the intermediate conductors 211A and 211B, etc. As a result, strict positioning precision is not required when stacking the intermediate conductors 211A and 211B and the insulating sheets 213A to 213C, improving workability.

[0040] Furthermore, the distance between the intermediate conductors 211A, 211B and the conductive member is automatically determined by which insulating sheet layers the intermediate conductors 211A, 211B are disposed between. Therefore, when manufacturing the heat dissipation sheet 210, there is no need to worry about the accuracy of positioning the intermediate conductors 211A, 211B in the y direction within the heat dissipation sheet 210. In this way, by disposing the intermediate conductors 211A, 211B between different layers of the three-layer heat dissipation sheet 210 made up of three insulating sheets 213A to 213C, it is possible to prevent the intermediate conductors 211A, 211B from contacting each other, and it is also possible to easily form an arrangement in which the intermediate conductors 211A, 211B are biased toward the front and back sides of the heat dissipation sheet 210.

[0041] Since insulating sheets 213A-213C are made of resin-based materials, they contain a fair number of voids. However, in heat dissipation sheet 210 shown in Fig. 8, the insulating sheets have a three-layer structure, which prevents voids that penetrate heat dissipation sheet 210, i.e., prevents defects such as voids in insulating sheets 213A-213C from lining up and overlapping in the y direction. This prevents a decrease in insulation performance due to the effects of overlapping defects.

[0042] 8, the distance d5 between the intermediate conductors 211A and 211B in the x direction is set to d5≧0. However, if the potential difference between the intermediate conductors 211A and 211B is small, or if the effect on the divided voltage is negligible, then d5<0 may be satisfied.

[0043] Fig. 10 is a diagram showing heat dissipation sheets 210 provided on the upper arm base 300B and lower arm base 300A sides of circuit molded body 101. In the example shown in Fig. 10, intermediate conductors 211A, 211B are larger in area than the opposing upper arm base 300B and lower arm base 300A, and extend to the peripheral areas of the upper arm base 300B and lower arm base 300A. Although not shown, a similar structure is also present on the AC lead frame 302 and N lead frame 301 sides.

[0044] In this way, the area size of the intermediate conductor 211 (211A, 211B) is larger than the area size of the conductor members (upper arm base 300B, lower arm base 300A, AC lead frame 302, N lead frame 301), which increases the allowable range for the size and position of the intermediate conductor 211 and improves productivity. In addition, the margin for misalignment of the heat dissipation sheet 210 relative to the circuit molded body 101 can be increased.

[0045] Fig. 11 is a diagram similar to Fig. 10, but shows the case where intermediate conductor 211 is made larger than in Fig. 10 and d5 = 0. Note that, as shown in Fig. 8, intermediate conductors 211A and 211B are disposed between different insulating sheet layers, and therefore intermediate conductors 211A and 211B do not come into contact with each other even when d5 = 0.

[0046] In the case of Fig. 11, the tolerance for misalignment of the heat dissipation sheet 210 is further increased compared to Fig. 10, within the range in which the two intermediate conductors 211A, 211B cover the upper arm base 300B and the lower arm base 300A. Fig. 12 is a diagram showing a state in which the heat dissipation sheet 210 is misaligned to the right in the figure. Even if the heat dissipation sheet 210 is misaligned in this way, each intermediate conductor 211 can cover the entire opposing surfaces of the upper arm base 300B and the lower arm base 300A, and the tolerance for misalignment of the heat dissipation sheet 210 is increased. As a result, the ease of assembly can be improved.

[0047] In the above-described embodiment, the power module 100 for one phase of an inverter circuit has been described as an example. In the power module 100, the circuit molded body 101 for one phase is housed in the case 200. However, the configuration of this embodiment can be similarly applied to a semiconductor device having a configuration in which a plurality of circuit molded bodies 101 are housed in one case.

[0048] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0049] (C1) As shown in FIG. 5, the power module 100, which is a semiconductor device, includes an upper arm base 300B, which is a first conductor member to which a power semiconductor element 303U on the upper arm side of an inverter circuit is connected, a lower arm base 300A, which is a second conductor member to which a power semiconductor element 303L on the lower arm side of the inverter circuit is connected, a heat dissipation member 201 arranged opposite to the juxtaposed upper arm base 300B and lower arm base 300A, an intermediate conductor 211B facing the upper arm base 300B, a lower arm base 300A, and a heat dissipation member 201. The heat dissipation sheet 210 has an intermediate conductor 211A facing the arm base 300A, and an electrical insulating layer 212 containing the intermediate conductors 211A and 211B, and is an insulating member arranged between the juxtaposed upper arm base 300B and lower arm base 300A and the heat dissipation member 201, and the electrical insulating layer 212 has a first insulating layer L1 on which the first intermediate conductor 211B is arranged, a second insulating layer L2 on which the intermediate conductor 211A is arranged, and a third insulating layer L3 interposed between the first insulating layer L1 and the second insulating layer L2.

[0050] Since the third insulating layer L3 is interposed between the intermediate conductors 211A and 211B so as to be stacked, it is possible to prevent contact between the intermediate conductors 211A and 211B due to misalignment of the intermediate conductors 211A and 211B. Furthermore, in manufacturing the heat dissipation sheet 210, the tolerance range for the size and positioning accuracy of the intermediate conductors 211A and 211B is expanded, which also improves productivity.

[0051] (C2) Furthermore, the intermediate conductors 211A and 211B are set to either a first arrangement state in which a distance d4 from the lower arm base 300A to the heat dissipation member-side surface of the intermediate conductor 211A is set to be smaller than a distance d1 from the upper arm base 300B to the conductor member-side surface of the intermediate conductor 211B, as shown in Fig. 5, or a second arrangement state in which a distance d2 from the N lead frame 301 to the conductor member-side surface of the intermediate conductor 211A is set to be larger than a distance d3 from the AC lead frame 302 to the heat dissipation member-side surface of the intermediate conductor 211B, as shown in Fig. 6. In both the first arrangement state and the second arrangement state, contact between the intermediate conductors 211A and 211B can be prevented.

[0052] (C3) In (C2) above, when a DC current flows through the upper arm base 300B and an AC current flows through the lower arm base 300A, the first arrangement state shown in Fig. 5 is set, and when an AC current flows through the AC lead frame 302 and a DC current flows through the N lead frame 301, the second arrangement state shown in Fig. 6 is set. By placing the intermediate conductor facing the conductor member through which the AC current flows (lower arm base 300A, AC lead frame 302) closer to the conductor member than the side through which the DC current flows, it is possible to suppress the occurrence of corona discharge on the AC current side and improve insulation.

[0053] (C4) In the above (C1), as shown in FIG. 8, the heat dissipation sheet 210 includes an insulating sheet 213B made of an electrically insulating material and having an area facing the intermediate conductors 211A and 211B. The intermediate conductor 211B is laminated on one side of the insulating sheet 213B, and the intermediate conductor 211A is laminated on the other side of the insulating sheet 213B. The insulating sheet 213B is interposed between the intermediate conductors 211A and 211B in the lamination direction, preventing contact between the intermediate conductors 211A and 211B. This allows for less precise size and positioning of the intermediate conductors 211A and 211B, and allows the intermediate conductors 211A and 211B to be larger. This improves assembly workability.

[0054] (C5) In (C4) above, as shown in Fig. 8, the heat dissipation sheet 210 further includes insulating sheets 213A and 213C that have the same shape as the insulating sheet 213B and are made of an electrically insulating material, with the insulating sheet 213A being laminated on one side (the bottom side in the figure) of the insulating sheet 213B on which the intermediate conductor 211B is laminated, and the insulating sheet 213C being laminated on the other side (the top side in the figure) of the insulating sheet 213B on which the intermediate conductor 211A is laminated. By using insulating sheets 213A, 213B, and 213C of the same shape in this way, parts can be shared, reducing the number of part types and improving productivity.

[0055] Furthermore, when a resin-based material is used as the electrical insulating material, voids are likely to form. Therefore, by configuring electrical insulating layer 212 of heat dissipation sheet 210 as a laminate of three insulating sheets 213A, 213B, and 213C, the possibility of voids in each insulating sheet overlapping in the same position can be reduced, thereby improving insulation reliability.

[0056] (C6) In the above (C5), as shown in FIG. 9, the intermediate conductor 211B is fixed to the insulating sheet 213A, and the intermediate conductor 211A is fixed to the insulating sheet 213C, and the heat dissipation sheet 210 is formed by laminating the insulating sheet 213A to which the intermediate conductor 211B is fixed, the insulating sheet 213B, and the insulating sheet 213C to which the intermediate conductor 211A is fixed.

[0057] When manufacturing heat dissipation sheet 210 including intermediate conductors 211A and 211B, two sheets with intermediate conductors 214, each having intermediate conductors 211 fixed to one surface of heat dissipation sheet 213, and one heat dissipation sheet 213 are prepared. Then, sheets with intermediate conductors 214 are laminated on both the front and back surfaces of heat dissipation sheet 213 so that intermediate conductors 211 face toward heat dissipation sheet 213, as shown in Figure 9. In this way, by using sheets with intermediate conductors 214 having intermediate conductors 211 fixed thereto, the number of types of parts can be reduced to two, thereby improving the productivity of heat dissipation sheet 210.

[0058] (C7) In the above (C5), the intermediate conductors 211A and 211B are formed of conductive material of the same shape, as shown in Fig. 10. By using the intermediate conductors 211A and 211B of the same shape in this way, the number of types of parts can be reduced, and the productivity of the heat dissipation sheet 210 can be improved.

[0059] (C8) A plate-shaped heat dissipation sheet 210 used in the power module 100 of (C1) above, as shown in Fig. 5, includes an intermediate conductor 211B arranged in a region of the heat dissipation sheet 210 facing the upper arm base 300B, an intermediate conductor 211A arranged in a region of the heat dissipation sheet 210 facing the lower arm base 300A, a first insulating layer L1 on which the intermediate conductor 211B is arranged, a second insulating layer L2 on which the intermediate conductor 211A is arranged, and a third insulating layer L3 interposed between the first insulating layer L1 and the second insulating layer L2, and an electrical insulating layer 212 containing the intermediate conductors 211A and 211B. With this configuration, it is possible to prevent contact between the intermediate conductors 211A and 211B in the heat dissipation sheet 210 due to misalignment of the intermediate conductors 211A and 211B.

[0060] The above-described embodiments and various modifications are merely examples, and the present invention is not limited to these details as long as the features of the invention are not impaired. Furthermore, although various embodiments and modifications have been described above, the present invention is not limited to these details. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0061] 100...power module, 101...circuit molded body, 200...case, 201...heat dissipation member, 210...heat dissipation sheet, 211, 211A, 211B...intermediate conductor, 212...electrical insulating layer, 213, 213A, 213B, 213C...insulating sheet, 214...sheet with intermediate conductor, 300A...lower arm base, 300B...upper arm base, 301...N lead frame, 302...AC lead frame, 303L, 303U...power semiconductor element, 304L, 304U...diode, L1...first insulating layer, L2...second insulating layer, L3...third insulating layer

Claims

1. a first conductor member to which an upper arm switching element of the inverter circuit is connected; a second conductor member to which a switching element on a lower arm side of the inverter circuit is connected; a heat dissipation member disposed opposite the first and second conductor members arranged side by side; a first intermediate conductor facing the first conductive member, a second intermediate conductor facing the second conductive member, and an insulating member having an electrically insulating layer containing the first and second intermediate conductors, the insulating member being disposed between the juxtaposed first and second conductive members and the heat dissipation member; the electrical insulation layer includes a first insulation layer on which the first intermediate conductor is disposed, a second insulation layer on which the second intermediate conductor is disposed, and a third insulation layer interposed between the first insulation layer and the second insulation layer; The first and second intermediate conductors are A semiconductor device that is set to either a first arrangement state in which the distance from the second conductor member to the heat dissipation member-side facing surface of the second intermediate conductor is set to be smaller than the distance from the first conductor member to the conductor member-side facing surface of the first intermediate conductor, or a second arrangement state in which the distance from the second conductor member to the conductor member-side facing surface of the second intermediate conductor is set to be larger than the distance from the first conductor member to the heat dissipation member-side facing surface of the first intermediate conductor.

2. 2. The semiconductor device according to claim 1, When a direct current flows through the first conductor member and an alternating current flows through the second conductor member, the first arrangement state is set; The semiconductor device is set to the second arrangement state when an AC current flows through the first conductor member and a DC current flows through the second conductor member.

3. A first conductor member to which a switching element on the upper arm side of an inverter circuit is connected; a second conductor member to which a switching element on a lower arm side of the inverter circuit is connected; a heat dissipation member disposed opposite the first and second conductor members arranged side by side; a first intermediate conductor facing the first conductive member, a second intermediate conductor facing the second conductive member, and an insulating member having an electrically insulating layer containing the first and second intermediate conductors, the insulating member being disposed between the juxtaposed first and second conductive members and the heat dissipation member; the electrical insulation layer includes a first insulation layer on which the first intermediate conductor is disposed, a second insulation layer on which the second intermediate conductor is disposed, and a third insulation layer interposed between the first insulation layer and the second insulation layer; the insulating member includes a first insulating sheet having an area facing the first and second intermediate conductors and made of an electrically insulating material; The semiconductor device comprises: the first intermediate conductor laminated on one surface of the first insulating sheet; and the second intermediate conductor laminated on the other surface of the first insulating sheet.

4. 4. The semiconductor device according to claim 3, the insulating member further includes second and third insulating sheets having the same shape as the first insulating sheet and made of the electrically insulating material; the second insulating sheet is laminated on one surface of the first insulating sheet on which the first intermediate conductor is laminated, The third insulating sheet is laminated on the other surface of the first insulating sheet on which the second intermediate conductor is laminated.

5. 5. The semiconductor device according to claim 4, the first intermediate conductor is fixed to the second insulating sheet; the second intermediate conductor is fixed to the third insulating sheet; A semiconductor device, wherein the insulating member is formed by stacking the second insulating sheet to which the first intermediate conductor is fixed, the first insulating sheet, and the third insulating sheet to which the second intermediate conductor is fixed.

6. 5. The semiconductor device according to claim 4, The first and second intermediate conductors are formed of the same conductor material.

7. 2. A plate-shaped insulating member used in the semiconductor device according to claim 1, the first intermediate conductor disposed in a first region of the insulating member; the second intermediate conductor disposed in a second region of the insulating member that is different from the first region; An insulating member comprising: the first insulating layer on which the first intermediate conductor is arranged, the second insulating layer on which the second intermediate conductor is arranged, and the third insulating layer interposed between the first insulating layer and the second insulating layer, and the electrically insulating layer containing the first and second intermediate conductors.

Images