Power semiconductor module and method of manufacturing power semiconductor module

Abstract

A power semiconductor module includes an AC bus bar having a first side facing a first substrate and a second side facing a second substrate. The first power transistor die has a drain terminal connected to the first metal region of the first substrate and a source terminal connected to the first side of the AC bus bar. A second power transistor die has a drain terminal connected to the second side of the AC bus bar and a source terminal connected to the first metal region of the second substrate. The first and second DC bus bars are connected to the first metal regions of the respective substrates, vertically overlap each other, and protrude from a first side of the molded body encapsulating the power transistor die. The AC bus bar protrudes from a different side of the molded body from the DC bus bar.

Description

Background Art

[0001] Within the electric drive train, the traction inverter controls the electric motor. The traction inverter is an important component in an electric vehicle because the inverter determines the drive behavior. Regardless of whether the motor is synchronous, asynchronous or brushless DC, the traction inverter always functions in a similar way and can be controlled by a system including power semiconductor modules. Power semiconductor modules should be designed to minimize switching losses and maximize thermal efficiency. The traction inverter drives the electric motor and captures the energy released through regenerative braking and feeds this energy back to the battery. As a result, the vehicle's cruising range is directly related to the efficiency of the traction inverter. Therefore, the inductance of the power semiconductor module should be as low as possible to reduce switching losses, especially when fast switching power transistor dies (chips) such as SiC MOSFETs (metal oxide semiconductor field effect transistors) are used in the module.

[0002] Conventional power semiconductor modules have an inductance as low as 3.5nH, which is not low enough for SiC MOSFET and other types of fast switching power transistor technology. Chip embedding technology produces inductances as low as about 700pH, but lower inductance will produce improved efficiency. In addition, stray inductance cannot be completely avoided and adds to the total inductance of the power semiconductor module.

[0003] Therefore, there is a need for an improved power semiconductor module design with ultra-low inductance below 700 pH. Summary of the invention

[0004] According to an embodiment of the power semiconductor module, the power semiconductor module includes: a first substrate; a second substrate; an AC bus bar, the AC bus bar having a first side facing the first substrate and a second side facing the second substrate; a first power transistor die, the first power transistor die having a drain terminal connected to a first metal region of the first substrate and a source terminal connected to the first side of the AC bus bar; a second power transistor die, the second power transistor die having a drain terminal connected to the second side of the AC bus bar and a source terminal connected to the first metal region of the second substrate; a molded body, the molded body encapsulating the first power transistor die and the second power transistor die; a first DC bus bar, the first DC bus bar connected to the first metal region of the first substrate and protruding from the first side of the molded body; and a second DC bus bar, the second DC bus bar connected to the first metal region of the second substrate, vertically overlapping with the first DC bus bar, and protruding from the first side of the molded body, wherein the AC bus bar protrudes from a different side of the molded body from the first DC bus bar and the second DC bus bar.

[0005] According to an embodiment of a method for manufacturing a power semiconductor module, the method includes: connecting a drain terminal of a first power transistor die to a first metal region of a first substrate; connecting a first side of an AC bus bar to a source terminal of the first power transistor die; connecting a drain terminal of a second power transistor die to a second side of the AC bus bar; connecting a first metal region of the second substrate to a source terminal of the second power transistor die; connecting a first DC bus bar to the first metal region of the first substrate; connecting a second DC bus bar to the first metal region of the second substrate; and encapsulating the first power transistor die and the second power transistor die in a molded body, wherein the first DC bus bar protrudes from the first side of the molded body,

[0006] wherein the second DC bus bar vertically overlaps the first DC bus bar and protrudes from a first side of the molded body, wherein the AC bus bar protrudes from a different side of the molded body than the first and second DC bus bars.

[0007] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The elements of the drawings are not necessarily drawn to scale relative to each other. The same reference numerals represent corresponding similar parts. The features of the various illustrated embodiments may be combined unless they exclude each other. The embodiments are illustrated in the drawings and described in detail in the following description.

[0009] Figure 1 A cross-sectional view of an embodiment of a power semiconductor module is shown.

[0010] Figure 2 A cross-sectional view of a power semiconductor module according to another embodiment is shown.

[0011] Figures 3A to 3G Shown are top plan views of a power semiconductor module during different manufacturing stages according to an embodiment. DETAILED DESCRIPTION

[0012] Embodiments described herein provide a power semiconductor module design with ultra-low inductance below 700 pH and a method for manufacturing the module. Ultra-low inductance is achieved by vertically overlapping positive (+) and negative (-) DC busbar connections, which creates a small current loop area, such as a commutation loop, for efficiently distributing current. In addition, high-side and low-side power transistor dies forming a power electronic circuit included in the module are stacked on opposite sides of the AC busbar.

[0013] Die stacking may result in higher thermal resistance even if the power semiconductor module is cooled from both sides by corresponding primary thermal paths within the module. Any increase in thermal resistance may be mitigated by adding one or more auxiliary thermal paths that supplement the primary thermal paths by forming thermal connections between AC bus bars and electrically isolated regions of the upper and / or lower substrates included in the power semiconductor module. Each auxiliary thermal path may be implemented by a metal or ceramic spacer, a brazed substrate, a half-edge substrate, a sintered joint, or any other type of heat conductor having a higher thermal conductivity than the molded body encapsulating the power transistor die.

[0014] Exemplary embodiments of a power semiconductor module and a method for manufacturing such a power semiconductor module are described below with reference to the accompanying drawings. Unless explicitly stated otherwise, any of the embodiments described below may be used interchangeably.

[0015] Figure 1 A cross-sectional view of an embodiment of a molded power semiconductor module 100 is shown. The power semiconductor module 100 may be connected to a circuit board 102, such as a PCB (printed circuit board), a capacitor bank with a power supply, etc., to form a part of a power electronic circuit used in various power applications (e.g., in a DC / AC inverter, a DC / DC converter, an AC / DC converter, a DC / AC converter, an AC / AC converter, a multi-phase inverter, an H-bridge, etc.). For example, the power electronic circuit implemented by the molded power semiconductor module 100 and the circuit board 102 may be a traction inverter for controlling an electric motor.

[0016] The molded power semiconductor module 100 comprises a first substrate 104, a second substrate 106 and an AC busbar 108, the AC busbar 108 having a first side 110 facing the first substrate 104 and a second side 112 facing the second substrate 106. The first substrate 104 can be, for example, a DBC (direct bonded copper) substrate, an AMB (active metal brazing) substrate or an IMS (insulated metal substrate), wherein in each case an insulator 114 such as a ceramic separates an inner metallized side 116 and an outer metallized side 118 of the first substrate 104 from one another. The second substrate 106 can also be a DBC substrate, an AMB substrate or an IMS, wherein in each case an insulator 120 such as a ceramic separates an inner metallized side 122 and an outer metallized side 124 of the second substrate 106 from one another. Alternatively, the substrates 104, 106 can be, for example, lead frames.

[0017] The molded power semiconductor module 100 also includes one or more first power transistor dies 126 having a drain terminal 128 electrically and thermally connected to a first metal region 130 of the first substrate 104, for example, by a die attach material or a sintered joint 132, and a source terminal 134 electrically and thermally connected to a first side 110 of the AC bus bar 108 by a spacer 136 such as a Cu block.

[0018] The molded power semiconductor module 100 also includes one or more second power transistor dies 138 having a drain terminal 140 electrically and thermally connected to the second side 112 of the AC bus bar 108, for example, by a die attach material or a sintered joint 142, and a source terminal 144 electrically and thermally connected to a first metal region 146 of the second substrate 106 by a spacer 148, such as a Cu block. The spacers 136, 148 prevent contact between the source terminals 144 of the power transistor dies 126, 138 and the AC bus bar 108. A molded body 150, such as a molding compound or similar type of resin, encapsulates the power transistor dies 126, 138.

[0019] A thermal conductor 149 may be connected between the first metal region 130 of the first substrate 104 and the first side 110 of the AC bus bar 108, the thermal conductor 149 having a higher thermal conductivity than the molded body 150. The second power transistor die 138 may vertically overlap the thermal conductor 149, wherein the vertical overlap area is Figure 1 outside the view in .

[0020] like Figure 1 As shown, the power transistor dies 126, 138 are vertical power transistor dies. For vertical power transistor dies, the primary current flow path is between the front and back sides of the corresponding dies 126, 138. The drain terminals 128, 140 are generally disposed on the back sides of the corresponding dies 126, 138, with the source terminals 134, 144 and the corresponding gate terminals 151, 152 on the front sides of the dies. The gate terminal 151 of each first power transistor die 126 can be electrically connected to the second metal region 153 of the first substrate 104 via a first bonding wire 155. The gate terminal 152 of each second power transistor die 138 can be electrically connected to the third metal region 157 of the first substrate 104 via a second bonding wire 159. The first power transistor die 126 and the second power transistor die 138 can be a power Si or SiC power MOSFET (metal oxide semiconductor field effect transistor) die, a HEMT (high electron mobility transistor) die, an IGBT (insulated gate bipolar transistor) die, a JFET (junction field effect transistor) die, etc.

[0021] The first power transistor die 126 and the second power transistor die 138 can be electrically interconnected to form a power electronic circuit such as a half-bridge, for example, where the first power semiconductor die(s) 126 form a high-side switch of the half-bridge and the second power semiconductor die(s) 138 form a low-side switch of the half-bridge. In the case of a half-bridge formed by the first power transistor die 126 and the second power transistor die 138, the AC bus bar 108 provides a switch node connection to the half-bridge. Additional types of semiconductor dies may be included in the molded power semiconductor module 100, such as power diode dies, logic dies, controller dies, gate driver dies, etc.

[0022] The molded power semiconductor module 100 further includes a first DC bus bar 154 at a positive (+) DC potential and connected to the first metal region 130 of the first substrate 104 and protruding from a first side 156 of the molded body 150. A second DC bus bar 158 at a negative (-) DC potential or grounded is connected to the first metal region 146 of the second substrate 106, vertically overlapping the first DC bus bar 154 ( Figure 1 The AC bus bar 108 protrudes from a side 160 of the molded body 150 different from the first DC bus bar 154 and the second DC bus bar 158.

[0023] Current flows from the first DC bus bar 154 into the molded power semiconductor module 100, through the first power transistor die(s) 126 and out through the AC bus bar 108. The current return path is through the AC bus bar 108 and the second power transistor die(s) 138 to the second DC bus bar 158. The current supply and return paths are Figure 1 The corresponding dotted lines in .

[0024] A small module footprint and ultra-low inductance below 700 pH are achieved by vertically overlapping the positive (+) DC bus bar 154 and the negative (-) DC bus bar 158, which forms a small current loop area that effectively distributes current, such as a commutation loop. In order to vertically overlap the positive (+) DC bus bar 154 and the negative (-) DC bus bar 158 in a compact area, the first power transistor die 126 and the second power transistor die 138 are vertically stacked on each other on opposite sides 110, 112 of the AC bus bar 108, thereby reducing stray inductance to support higher switching frequencies.

[0025] The molded power semiconductor module 100 may be cooled from both sides by respective heat sinks 162, 164 and corresponding primary thermal paths 166, 168 within the molded power semiconductor module 100. The bottom (lower) heat sink 162 may be coupled to the outer metallized side 118 of the first substrate 104 by a first thermal interface material 170. The top (upper) heat sink 164 may be coupled to the outer metallized side 124 of the second substrate 106 by a second thermal interface material 172. The heat sinks 162, 164 may be passively or actively cooled.

[0026] A first (lower) primary thermal path 166 within the molded power semiconductor module 100 includes the first metal region 130 of the first substrate 104, a die attach material or sintered joint 132 connecting the drain terminal 128 of each first power transistor die 126 to the first metal region 130 of the first substrate 104, the insulator 114 of the first substrate 104, and the outer metallized side 118 of the first substrate 104. A second (upper) primary thermal path 168 within the molded power semiconductor module 100 includes the first metal region 146 of the second substrate 106, each spacer 148 connecting the source terminal 144 of the second power transistor die 138 to the first metal region 146 of the second substrate 106, the insulator 120 of the second substrate 106, and the outer metallized side 124 of the second substrate 106.

[0027] Figure 1 Simulations of the power module design shown have demonstrated module inductances in the range of 270pH to 550pH, depending on the thickness of the lower spacer 132 and the upper spacer 148. Even if the molded power semiconductor module 100 is cooled from both sides, Figure 1 The die stacking arrangement shown in can also result in a higher thermal resistance (Rth). More specifically, the upper spacer 148 included in the second (upper) main thermal path 168 can increase the Rth of the second main thermal path 168 between the second power transistor die 138 and the outer metallization side 124 of the second substrate 106.

[0028] Figure 2 FIG. 1 shows a cross-sectional view of a molded power semiconductor module 100 according to another embodiment. Figure 21 , the molded power semiconductor module 100 includes one or more auxiliary thermal paths 200, 202 that supplement the primary thermal paths 166, 168. The first (lower) auxiliary thermal path 200 may be formed by a thermal conductor 204 connected between the first side 110 of the AC bus bar 108 and a metal region 206 of the first substrate 104, the metal region 206 of the first substrate 104 being electrically isolated from the first metal region 130 of the first substrate 104. The thermal conductor 204 is connected between the first side 110 of the AC bus bar 108 and a separate metal region 206 of the first substrate 104 before encapsulating the power transistor dies 126, 138 in the molded body 150.

[0029] The thermal conductor 204 has a higher thermal conductivity than the molded body 150, thus resulting in a lower module Rth. For example, the thermal conductor 204 can be a metal or ceramic spacer attached to the separate metal region 206 of the first substrate 104 and the first side 110 of the AC bus bar 108, for example, by a die attach material or a sintered joint 208. In another embodiment, the thermal conductor 204 is a sintered joint between the separate metal region 206 of the first substrate 104 and the first side 110 of the AC bus bar 108.

[0030] Alone or in combination, the second (upper) auxiliary thermal path 202 may be formed by a thermal conductor 210 connected between the second side 112 of the AC bus bar 108 and a metal region 212 of the second substrate 106, the metal region 212 of the second substrate 106 being electrically isolated from the first metal region 146 of the second substrate 106. The thermal conductor 210 is connected between the second side 112 of the AC bus bar 108 and a separate metal region 212 of the second substrate 106 before encapsulating the power transistor dies 126, 138 in the molded body 150.

[0031] The heat conductor 210 connected between the second side 112 of the AC bus bar 108 and the separate metal region 212 of the second substrate 106 has a higher thermal conductivity than the molded body 150, thus resulting in a lower module Rth. For example, the heat conductor 210 connected between the second side 112 of the AC bus bar 108 and the separate metal region 212 of the second substrate 106 may be a metal or ceramic spacer attached to the separate metal region 212 of the second substrate 106 and the second side 112 of the AC bus bar 108, for example, by a die attach material or a sintered joint 214. In another embodiment, the heat conductor 210 connected between the second side 112 of the AC bus bar 108 and the separate metal region 212 of the second substrate 106 is a sintered joint between the separate metal region 212 of the second substrate 106 and the second side 112 of the AC bus bar 108.

[0032] As previously explained herein, the substrates 104, 106 may be DBC substrates, AMB substrates, or IMS. In each of these cases, the metal regions 206, 212 of the substrates 104, 106 to which the corresponding heat conductors 204, 210 are connected may be electrically isolated from the first metal regions 130, 146 of the respective substrates 104, 106 by patterning the inner metallized sides 116, 122 of the substrates 104, 106 facing inward toward each other. Also as previously explained herein, the substrates 104, 106 may alternatively be lead frames having features formed by stamping, punching, etching, etc. In this case, the metal regions 206, 212 of the substrates 104, 106 to which the corresponding heat conductors 204, 210 are connected may be implemented as additional lead frames.

[0033] Figures 3A to 3G Top plan views are shown during different stages of manufacturing a molded power semiconductor module 100 according to an embodiment.

[0034] Figure 3A A plurality of first power transistor dies 126 are shown attached to the inner patterned metallization side 116 of the first substrate 104, wherein the drain terminal 128 (at Figure 3A 1 (out of view in FIG. 1 ) is electrically and thermally connected to the first metal region 130 of the first substrate 104. As an example, Figure 3A 1 , five (5) first power transistor dies 126 are shown. However, more or fewer first power transistor dies 126 may be used. Typically, one or more first power transistor dies 126 are attached to the inner patterned metallization side 116 of the first substrate 104. If more than one first power transistor die 126 is used, the first power transistor dies 126 may be electrically coupled in parallel within the molded power semiconductor module 100 to form a switching device, such as a high-side switch of a half-bridge.

[0035] Also in Figure 3A , a first (+) DC bus bar 154 is connected to a first metal region 130 of a first substrate 104, and corresponding gate leads 300, 302 are connected to separate metal gate regions 153, 157 of the first substrate 104. The gate leads 300, 302 provide signal connections for the power transistor dies 126, 138, while the first DC bus bar 154 provides a positive (+) DC potential for the drain terminal 128 of each first power transistor die 126. The gate leads 300, 302 and the first DC bus bar 154 can be provided as part of a lead frame or other type of patterned metal sheet, for example, where the first DC bus bar 154 can have a heavier gauge than the gate leads 300, 302.

[0036] Figure 3BThe first (lower) side 110 of the AC bus bar 108 connected to the source terminal 134 of each first power transistor die 126 is shown (in FIG. Figure 3B For example, the AC bus bar 108 may be provided as a lead frame or other type of patterned metal sheet. The spacer 136 (in Figure 3B A first power transistor die 126 (outside of the view in FIG. 1 ) may be interposed between the source terminal 134 of each first power transistor die 126 and the first side 110 of the AC bus bar 108 to provide a controlled spacing that avoids contact between the source terminal 134 of each first power transistor die 126 and the first side 110 of the AC bus bar 108.

[0037] Figure 3C A plurality of second power transistor dies 138 are shown attached to the second (upper) side 112 of the AC bus bar 108, wherein the drain terminal 140 (at Figure 3C 1 and 10. As an example, Figure 3C Five (5) second power transistor dies 138 are shown in the molded power semiconductor module 100. However, more or fewer second power transistor dies 138 may be used. Typically, one or more second power transistor dies 138 are attached to the second side 112 of the AC bus bar 108. If more than one second power transistor die 138 is used, the second power transistor dies 138 may be electrically coupled in parallel within the molded power semiconductor module 100 to form a switching device, such as a low-side switch of a half-bridge.

[0038] exist Figure 3C In the embodiment, the first power transistor die 126 is identical to the second power transistor die 138, which means that the first power transistor die 126 is exactly the same die type (e.g., SiC MOSFET die) as the second power transistor die 138. Due to inherent process variations in manufacturing the power transistor dies 126, 128, this does not necessarily mean that the first power transistor die 126 has the same physical dimensions (e.g., length, width, thickness, etc.) and / or operating parameters (e.g., threshold voltage, rated voltage, rated current, etc.) as the second power transistor die 138.

[0039] Figure 3C Each second power transistor die 138 is also shown vertically overlapping a corresponding first power transistor die 126. Figure 3CIn the horizontal plane defined by the x and y directions, each second power transistor die 138 is rotated 90° relative to the first power transistor die 126 below, so that the gate terminal 151 of the first power transistor die 126 below is not blocked by the second power transistor die 138 above, and can therefore be used for contact, detection, bonding, etc.

[0040] Figure 3D The gate terminal 151 of each first power transistor die 126 is shown electrically connected to a corresponding metal gate region 153 of the first substrate 104 by a first bond wire 155. Each first bond wire 155 that vertically overlaps the AC bus bar 108 passes through a gap 304 in the AC bus bar 108 to accommodate the height of the first bond wire 155 without shorting the first bond wire 155 to the AC bus bar 108.

[0041] Figure 3D Also shown is a gate terminal 152 of each second power transistor die 138 electrically connected to a corresponding metal gate region 157 of the first substrate 104 by a second bond wire 159. Each second bond wire 159 vertically overlapping the AC bus bar 108 passes through a gap 304 in the AC bus bar 108 that is the same or different than the first bond wire(s) 155 implemented to accommodate the height of the second bond wire 159 without shorting the second bond wire 159 to the AC bus bar 108.

[0042] Figure 3E Shown in Figure 3D A cross-sectional view after processing is shown in the area where the first bond wire 155 and the second bond wire 159 pass through the same gap 304 in the AC bus bar 108 .

[0043] Figure 3F The inner (lower) metallization side 122 of the second substrate 106 is shown. Figure 3F , the inner metallized side 122 of the second substrate 106 has one or more gaps 306, which may extend through the entire thickness of the inner metallized side 122, such that the insulator 120 of the second substrate 106 is exposed through each gap 306 in the inner metallized side 122. Alternatively, the gap(s) 306 may extend only partially through the inner metallized side 122 of the second substrate 106, such that the insulator 120 is not exposed at the inner (lower) side of the second substrate 106.

[0044] Figure 3G Shown with Figure 3ESame cross-sectional view, but after the first metal region 146 of the second substrate 106 is thermally and electrically connected to the source terminal 144 of each second power transistor die 138 through a corresponding spacer 148. Each spacer 148 ensures sufficient clearance between the first metal region 146 of the second substrate 106 and the gate terminal 152 of the corresponding second power transistor die 138.

[0045] Each second bond wire 159 connected to the gate terminal 152 of the second power transistor die 138 vertically overlapping the second substrate 106 is received by a corresponding gap 306 in the inner metallization side 122 of the second substrate 106 to avoid shorting between the source potential and the gate potential. Each second bond wire 159 vertically overlapping the AC bus bar 108 passes through a corresponding gap 304 in the AC bus bar 108 to facilitate connection to the corresponding metal gate region 157 of the first substrate 104 and avoid shorting between the AC / switch node and the gate potential. After the die connection is made, the power transistor dies 126, 138 can be packaged in the molded body 150 to produce Figure 1 or Figure 2 A molded power semiconductor module is shown. The packaging process may involve injection molding, film-assisted molding, etc.

[0046] The embodiments described herein provide a power semiconductor module that is easier to manufacture due to further support points. Furthermore, the AC busbars are cooled, which may become necessary at high currents. In addition, the thermal resistance of the module is improved by providing an auxiliary thermal path in addition to the main thermal path within the module.

[0047] Although the present disclosure is not limited in this regard, the following numbered examples demonstrate one or more aspects of the present disclosure.

[0048] Example 1. A power semiconductor module, comprising: a first substrate; a second substrate; an AC bus bar, the AC bus bar having a first side facing the first substrate and a second side facing the second substrate; a first power transistor die, the first power transistor die having a drain terminal connected to a first metal region of the first substrate and a source terminal connected to the first side of the AC bus bar; a second power transistor die, the second power transistor die having a drain terminal connected to the second side of the AC bus bar and a source terminal connected to the first metal region of the second substrate; a molded body, the molded body encapsulating the first power transistor die and the second power transistor die; a first DC bus bar, the first DC bus bar connected to the first metal region of the first substrate and protruding from the first side of the molded body; and a second DC bus bar, the second DC bus bar connected to the first metal region of the second substrate, vertically overlapping with the first DC bus bar, and protruding from the first side of the molded body, wherein the AC bus bar protrudes from a side of the molded body different from the first DC bus bar and the second DC bus bar.

[0049] Example 2. The power semiconductor module described in Example 1 further includes: a thermal conductor connected between the second metal region of the first substrate and the first side of the AC bus bar, wherein the second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, and wherein the thermal conductor has a higher thermal conductivity than the molded body.

[0050] Example 3. The power semiconductor module of Example 2, wherein the thermal conductor comprises a metal or ceramic spacer attached to the second metal region of the first substrate and the first side of the AC bus bar.

[0051] Example 4. The power semiconductor module of Example 2, wherein the thermal conductor comprises a sintered joint between the second metal region of the first substrate and the first side of the AC bus bar.

[0052] Example 5. The power semiconductor module described in any one of Examples 1 to 4 further includes: a thermal conductor connected between the second side of the AC bus bar and the second metal region of the second substrate, wherein the second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, and wherein the thermal conductor has a higher thermal conductivity than the molded body.

[0053] Example 6. The power semiconductor module of Example 5, wherein the thermal conductor comprises a metal or ceramic spacer attached to the second metal region of the second substrate and the second side of the AC bus bar.

[0054] Example 7. The power semiconductor module of Example 5, wherein the thermal conductor comprises a sintered joint between the second metal region of the second substrate and the second side of the AC bus bar.

[0055] Example 8. The power semiconductor module described in Example 1 further includes: a first heat conductor, which is connected between a second metal region of the first substrate and a first side of the AC bus bar; and a second heat conductor, which is connected between a second side of the AC bus bar and a second metal region of the second substrate, wherein the second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, wherein the second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, wherein both the first heat conductor and the second heat conductor have a higher thermal conductivity than the molded body.

[0056] Example 9. The power semiconductor module of Example 8, wherein the first thermal conductor comprises a first metal or ceramic spacer attached to a second metal region of the first substrate and a first side of the AC bus bar, and wherein the second thermal conductor comprises a second metal or ceramic spacer attached to a second metal region of the second substrate and a second side of the AC bus bar.

[0057] Example 10. The power semiconductor module of Example 8, wherein the first thermal conductor comprises a first sintered joint between the second metal region of the first substrate and the first side of the AC bus bar, and wherein the second thermal conductor comprises a second sintered joint between the second metal region of the second substrate and the second side of the AC bus bar.

[0058] Example 11. A power semiconductor module as described in any one of Examples 1 to 10, wherein a gate terminal of a first power transistor die is electrically connected to a second metal region of the first substrate via a first bonding wire passing through a gap in an AC bus bar, and wherein a gate terminal of a second power transistor die is electrically connected to a third metal region of the first substrate via a second bonding wire passing through the same or different gap in the AC bus bar.

[0059] Example 12. A power semiconductor module as described in any one of Examples 1 to 10, wherein a gate terminal of a first power transistor die is electrically connected to a second metal region of the first substrate via a first bonding wire passing through a gap in a first metal region of the second substrate, and wherein a gate terminal of a second power transistor die is electrically connected to a third metal region of the first substrate via a second bonding wire passing through the same or different gap in the first metal region of the second substrate.

[0060] Example 13. A power semiconductor module as described in any one of Examples 1 to 12, wherein the first power transistor die and the second power transistor die are identical, wherein the second power transistor die vertically overlaps the first power transistor die, and wherein, in a horizontal plane, the second power transistor die is rotated 90° relative to the first power transistor die so that a gate terminal of the first power transistor die is not blocked by the second power transistor die.

[0061] Example 14. The power semiconductor module described in any one of Examples 1 to 13 further includes: a thermal conductor connected between the first metal region of the first substrate and the first side of the AC bus bar, wherein the second power transistor die vertically overlaps the thermal conductor, and wherein the thermal conductor has a higher thermal conductivity than the molded body.

[0062] Example 15. A method for manufacturing a power semiconductor module, the method comprising: connecting a drain terminal of a first power transistor die to a first metal area of ​​a first substrate; connecting a first side of an AC bus bar to a source terminal of the first power transistor die; connecting a drain terminal of a second power transistor die to a second side of the AC bus bar; connecting a first metal area of ​​the second substrate to a source terminal of the second power transistor die; connecting a first DC bus bar to a first metal area of ​​the first substrate; connecting a second DC bus bar to a first metal area of ​​the second substrate; and encapsulating the first power transistor die and the second power transistor die in a molded body, wherein the first DC bus bar protrudes from a first side of the molded body, wherein the second DC bus bar vertically overlaps with the first DC bus bar and protrudes from the first side of the molded body, and wherein the AC bus bar protrudes from a side of the molded body different from the first DC bus bar and the second DC bus bar.

[0063] Example 16. The method described in Example 15 further includes: before packaging, connecting a thermal conductor between the second metal region of the first substrate and the first side of the AC bus bar, wherein the second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, and wherein the thermal conductor has a higher thermal conductivity than the molded body.

[0064] Example 17. The method of Example 15 further includes: before packaging, connecting a thermal conductor between the second side of the AC bus bar and the second metal region of the second substrate, wherein the second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, and wherein the thermal conductor has a higher thermal conductivity than the molded body.

[0065] Example 18. The method of any one of Examples 15 to 17 further includes: before packaging, connecting a first thermal conductor between a second metal region of the first substrate and a first side of an AC bus bar, and connecting a second thermal conductor between a second side of the AC bus bar and a second metal region of the second substrate, wherein the second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, wherein the second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, wherein both the first thermal conductor and the second thermal conductor have a higher thermal conductivity than the molded body.

[0066] Example 19. The method described in any one of Examples 15 to 18 further includes: before packaging, electrically connecting the gate terminal of the first power transistor die to the second metal region of the first substrate via a first bonding wire passing through a gap in the AC bus bar, and electrically connecting the gate terminal of the second power transistor die to the third metal region of the first substrate via a second bonding wire passing through the same or different gap in the AC bus bar.

[0067] Example 20. The method described in any one of Examples 15 to 18 further includes: before packaging, electrically connecting the gate terminal of the first power transistor die to the second metal region of the first substrate via a first bonding wire passing through a gap in the first metal region of the second substrate, and electrically connecting the gate terminal of the second power transistor die to the third metal region of the first substrate via a second bonding wire passing through the same or different gap in the first metal region of the second substrate.

[0068] Example 21. The method of any one of Examples 15 to 20, wherein the first power transistor die is identical to the second power transistor die, wherein the second power transistor die vertically overlaps the first power transistor die, and wherein the method further comprises: before packaging, rotating the second power transistor die 90° relative to the first power transistor die in a horizontal plane so that the gate terminal of the first power transistor die is not blocked by the second power transistor die.

[0069] Terms such as "first", "second", etc. are used to describe various elements, regions, parts, etc., and are not intended to be limiting. Throughout the specification, the same terms refer to the same elements.

[0070] As used herein, the terms "having", "containing", "including", "comprising", etc. are open terms that indicate the presence of stated elements or features, but do not exclude additional elements or features. Unless the context clearly indicates otherwise, the articles "a", "an", and "the" are intended to include the plural as well as the singular.

[0071] Unless otherwise expressly stated, the expression "and / or" should be interpreted as including all possible conjunctive and disjunctive combinations. For example, the expression "A and / or B" should be interpreted as meaning only A, only B, or both A and B. The expression "at least one of..." should be interpreted in the same manner as "and / or", unless otherwise expressly stated. For example, the expression "at least one of A and B" should be interpreted as meaning only A, only B, or both A and B.

[0072] It should be understood that the features of the various embodiments described herein may be combined with each other, unless specifically stated otherwise.

[0073] Although specific embodiments have been shown and described herein, it will be appreciated by those of ordinary skill in the art that various alternatives and / or equivalent embodiments may replace the specific embodiments shown and described without departing from the scope of the present invention. The present application is intended to cover any modifications or variations of the specific embodiments discussed herein. Therefore, the present invention is intended to be limited only by the claims and their equivalents.

Claims

1. A power semiconductor module, comprising: a first substrate; a second substrate; an AC bus bar having a first side facing the first substrate and a second side facing the second substrate; a first power transistor die having a drain terminal connected to a first metal region of the first substrate and a source terminal connected to the first side of the AC bus bar; a second power transistor die having a drain terminal connected to the second side of the AC bus bar and a source terminal connected to the first metal region of the second substrate; a molded body encapsulating the first power transistor die and the second power transistor die; a first DC bus bar connected to the first metal region of the first substrate and protruding from a first side of the molded body; as well as a second DC bus bar connected to the first metal region of the second substrate, vertically overlapping the first DC bus bar, and protruding from the first side of the molded body, The AC bus bar protrudes from a side of the molded body different from the first DC bus bar and the second DC bus bar.

2. The power semiconductor module according to claim 1, further comprising: a heat conductor connected between the second metal region of the first substrate and the first side of the AC bus bar, The second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, The heat conducting body has a higher thermal conductivity than the molded body.

3. The power semiconductor module according to claim 2, wherein: The thermal conductor includes a metal or ceramic spacer attached to the second metal region of the first substrate and the first side of the AC bus bar.

4. The power semiconductor module according to claim 2, wherein: The thermal conductor includes a sintered joint between the second metal region of the first substrate and the first side of the AC busbar.

5. The power semiconductor module according to claim 1, further comprising: a heat conductor connected between the second side of the AC bus bar and the second metal region of the second substrate, The second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, The heat conducting body has a higher thermal conductivity than the molded body.

6. The power semiconductor module according to claim 5, wherein: The thermal conductor includes a metal or ceramic spacer attached to the second metal region of the second substrate and the second side of the AC bus bar.

7. The power semiconductor module according to claim 5, wherein: The thermal conductor includes a sintered joint between the second metal region of the second substrate and the second side of the AC busbar.

8. The power semiconductor module according to claim 1, further comprising: a first heat conductor connected between the second metal region of the first substrate and the first side of the AC bus bar; as well as a second heat conductor connected between the second side of the AC bus bar and a second metal region of the second substrate, The second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, The second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, The first heat conductor and the second heat conductor both have a higher thermal conductivity than the molded body.

9. The power semiconductor module according to claim 8, wherein: The first thermal conductor comprises a first metal or ceramic spacer attached to the second metal region of the first substrate and the first side of the AC bus bar, and wherein the second thermal conductor comprises a second metal or ceramic spacer attached to the second metal region of the second substrate and the second side of the AC bus bar.

10. The power semiconductor module according to claim 8, wherein: The first heat conductor comprises a first sintered joint between the second metal region of the first substrate and the first side of the AC busbar, and wherein the second heat conductor comprises a second sintered joint between the second metal region of the second substrate and the second side of the AC busbar.

11. The power semiconductor module according to claim 1, wherein: The gate terminal of the first power transistor die is electrically connected to a second metal region of the first substrate via a first bonding wire passing through a gap in the AC bus bar, and wherein the gate terminal of the second power transistor die is electrically connected to a third metal region of the first substrate via a second bonding wire passing through the same or different gap in the AC bus bar.

12. The power semiconductor module according to claim 1, wherein: A gate terminal of the first power transistor die is electrically connected to a second metal region of the first substrate via a first bonding wire passing through a gap in the first metal region of the second substrate, and wherein a gate terminal of the second power transistor die is electrically connected to a third metal region of the first substrate via a second bonding wire passing through the same or different gap in the first metal region of the second substrate.

13. The power semiconductor module according to claim 1, wherein: The first power transistor die and the second power transistor die are identical, wherein the second power transistor die vertically overlaps the first power transistor die, and wherein, in a horizontal plane, the second power transistor die is rotated 90° relative to the first power transistor die so that a gate terminal of the first power transistor die is not blocked by the second power transistor die.

14. The power semiconductor module according to claim 1, further comprising: a heat conductor connected between the first metal region of the first substrate and the first side of the AC bus bar, wherein the second power transistor die overlaps vertically with the heat conductor, The heat conducting body has a higher thermal conductivity than the molded body.

15. A method for manufacturing a power semiconductor module, the method comprising: connecting a drain terminal of a first power transistor die to a first metal region of a first substrate; connecting a first side of an AC bus bar to a source terminal of the first power transistor die; connecting a drain terminal of a second power transistor die to a second side of the AC bus bar; connecting a first metal region of a second substrate to a source terminal of the second power transistor die; connecting a first DC bus bar to the first metal region of the first substrate; connecting a second DC bus bar to the first metal region of the second substrate; as well as encapsulating the first power transistor die and the second power transistor die in a molded body, wherein the first DC bus bar protrudes from a first side of the molded body, wherein the second DC bus bar vertically overlaps the first DC bus bar and protrudes from the first side of the molded body, The AC bus bar protrudes from a side of the molded body different from the first DC bus bar and the second DC bus bar.

16. The method according to claim 15, further comprising: Prior to the packaging, connecting a thermal conductor between the second metal region of the first substrate and the first side of the AC bus bar, The second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, The heat conducting body has a higher thermal conductivity than the molded body.

17. The method according to claim 15, further comprising: Before the packaging, connecting a thermal conductor between the second side of the AC bus bar and the second metal region of the second substrate, The second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, The heat conducting body has a higher thermal conductivity than the molded body.

18. The method according to claim 15, further comprising: Prior to the packaging, a first heat conductor is connected between the second metal region of the first substrate and the first side of the AC bus bar, and a second heat conductor is connected between the second side of the AC bus bar and the second metal region of the second substrate, The second metal region of the first substrate is electrically isolated from the first metal region of the first substrate, The second metal region of the second substrate is electrically isolated from the first metal region of the second substrate, The first heat conductor and the second heat conductor both have a higher thermal conductivity than the molded body.

19. The method according to claim 15, further comprising: Prior to the packaging, the gate terminal of the first power transistor die is electrically connected to the second metal region of the first substrate by a first bonding wire passing through a gap in the AC bus bar, and the gate terminal of the second power transistor die is electrically connected to the third metal region of the first substrate by a second bonding wire passing through the same or different gap in the AC bus bar.

20. The method of claim 15, further comprising: Prior to the packaging, the gate terminal of the first power transistor die is electrically connected to the second metal region of the first substrate by a first bonding wire passing through a gap in the first metal region of the second substrate, and the gate terminal of the second power transistor die is electrically connected to the third metal region of the first substrate by a second bonding wire passing through the same or different gap in the first metal region of the second substrate.

21. The method according to claim 15, wherein: The first power transistor die is identical to the second power transistor die, wherein the second power transistor die vertically overlaps the first power transistor die, and wherein the method further comprises: Prior to the packaging, the second power transistor die is rotated 90° relative to the first power transistor die in a horizontal plane so that a gate terminal of the first power transistor die is not blocked by the second power transistor die.

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