Chip module with spatially restricted thermally conductive mounting body

Abstract

A module (100) that has the following features: • a carrier (102); • a body (104) that is at least partially thermally conductive and electrically insulating, mounted on only part of a main surface (128) of the support (102); • an at least partially electrically conductive rewiring structure (112) on the thermally conductive and electrically insulating body (104); • an electronic chip (106) mounted on the rewiring structure (112) and above the thermally conductive and electrically insulating body (104); wherein the rewiring structure (112) has several structured rewiring plates that are laterally spaced and do not overlap vertically; • an encapsulation means (108) which encapsulates at least part of the carrier (102), at least part of the thermally conductive and electrically insulating body (104), at least part of the rewiring structure (112) and at least part of the electronic chip (106), • wherein the thermally conductive and electrically insulating body (104) is smaller than the rewiring structure (112) and the support (102) with respect to its horizontal area along the main surface (128), thereby forming a gap between the rewiring structure (112) and the support (102), the gap being filled with the encapsulating agent (108).

Description

Background of the invention; Technical field of the invention

[0001] The present invention relates to a module and a method for manufacturing a module. Description of the relevant state of the art

[0002] Conventional encapsulation materials, such as mold structures, for electronic components, and especially electronic chips, have evolved to a point where the package no longer significantly impedes component performance. Encapsulating electronic components can protect them from the environment.

[0003] US 2017 / 0069569 A1 discloses a semiconductor package comprising a first substrate, a second substrate, and first and second conductive structures. The semiconductor package further includes a semiconductor chip and a sealing unit. The second substrates extend over a larger area than the semiconductor chips.

[0004] DE 39 31 634 A1 discloses a semiconductor device comprising a base plate, a copper first support plate with terminals, and an insulating second support plate. The semiconductor device also includes a semiconductor body. The insulating second support plate extends over a larger area than the semiconductor body.

[0005] DE 10 2008 060 300 A1 discloses a semiconductor device comprising a metal base plate, an insulating substrate with an insulating plate, metal foils, and semiconductor elements. The semiconductor device further comprises a housing. The insulating plate has a larger area than the semiconductor elements.

[0006] DE 10 2006 051 454 A1 discloses a semiconductor device comprising a base plate, an insulating substrate, a wiring pattern layer 14, and semiconductor chips. The semiconductor device also includes a resin packaging. The insulating substrate extends over a larger area than the semiconductor chips.

[0007] US 2013 / 0337613A1 discloses a power module package comprising a thermal diffusion layer, a ceramic coating layer, first and second lead frames, and semiconductor devices. The power module package also includes a molding compound. The ceramic coating layer covers a larger area than the semiconductor devices.

[0008] DE 10 2009 044 659 A1 discloses a power semiconductor module with a power semiconductor element connected to a cylindrical conductor and a surface of a terminal frame. An opening of the cylindrical conductor is exposed on a surface made of transfer resin. The sealing with the transfer resin is carried out such that terminal sections of the terminal frame protrude from the peripheral side sections of the transfer resin. The cylindrical conductor is conductively connected to a control circuit. The terminal sections of the terminal frame are each conductively connected to a main circuit.

[0009] US 2001 / 0050421A1 discloses a semiconductor device comprising a plurality of semiconductor devices mounted in one or more arrays on a substrate, a main current electrode mounted along the arrays of semiconductor devices and connected through the substrate to each of the plurality of semiconductor devices by means of a plurality of wires, an insulated base mounted on the main current electrode and covering the connection area of ​​the wires connecting the main current electrode, and a drive electrode mounted on the base and connected to each of the semiconductor devices.

[0010] US 2017 / 0077044A1 discloses a semiconductor device comprising a plurality of main terminals extending from one end of a base plate to its other end, a group of semiconductor chips on a side with a higher electrical potential arranged on one side of the main terminal and mounted on the base plate, and a group of semiconductor chips on a side with a lower electrical potential arranged on the other side of the main terminal and mounted on the base plate.The one main terminal has an extension section that extends in a direction perpendicular to the extension direction of the main terminal towards one of the two sides of the main terminal, and two adjacent semiconductor chips in one of the group of semiconductor chips on the side of the higher electrical potential and the group of semiconductor chips on the side of the lower electrical potential are arranged axially symmetrically with respect to the extension section.

[0011] However, there is still potential room to reduce manufacturing costs and simplify processing while maintaining high heat dissipation capability to remove heat generated during the operation of the package (packing, packing assembly). Summary of the invention

[0012] There may be a need for a mechanically and electrically reliable module that can be manufactured with minimal effort, while ensuring efficient heat dissipation during operation.

[0013] According to an exemplary embodiment, a module is provided comprising a carrier, an at least partially thermally conductive and electrically insulating body mounted on only a portion of a major surface of the carrier, an at least partially electrically conductive rewiring structure (redistribution structure) on the thermally conductive and electrically insulating body, an electronic chip mounted on the rewiring structure and above the thermally conductive and electrically insulating body, and an encapsulation means that encapsulates at least a portion of the carrier, at least a portion of the thermally conductive and electrically insulating body, at least a portion of the rewiring structure, and at least a portion of the electronic chip. The rewiring structure comprises multiple structured rewiring plates that are laterally spaced and do not overlap vertically.Furthermore, the module comprises an encapsulating means that encapsulates at least a portion of the substrate, at least a portion of the thermally conductive and electrically insulating body, at least a portion of the rewiring structure, and at least a portion of the electronic chip, wherein the thermally conductive and electrically insulating body is smaller than the rewiring structure and the substrate with respect to its horizontal area along the main surface. A gap is formed between the rewiring structure and the substrate, the gap being filled with the encapsulating means.

[0014] For example, a power module is described comprising a plate-like support, a plurality of plate-like thermally conductive and electrically insulating bodies mounted on a main surface of the support, a semiconductor power chip and a component, each mounted on or above one of the thermally conductive and electrically insulating bodies, and a mold-like encapsulating means encapsulating at least part of the support, at least part of the thermally conductive and electrically insulating bodies, at least part of the semiconductor power chip and at least part of the component.

[0015] According to yet another exemplary embodiment, a method for manufacturing a module is provided, comprising mounting a thermally conductive and electrically insulating body onto only a portion of a main surface of a carrier, mounting an at least partially electrically conductive rewiring structure onto the thermally conductive and electrically insulating body, mounting an electronic chip onto the rewiring structure and above the thermally conductive and electrically insulating body, and encapsulating at least a portion of the carrier, at least a portion of the thermally conductive and electrically insulating body, at least a portion of the rewiring structure, and at least a portion of the electronic chip by an encapsulating means. The rewiring structure comprises several structured rewiring plates that are laterally spaced and do not overlap vertically.Furthermore, the module comprises an encapsulating means that encapsulates at least a portion of the substrate, at least a portion of the thermally conductive and electrically insulating body, at least a portion of the rewiring structure, and at least a portion of the electronic chip, wherein the thermally conductive and electrically insulating body is smaller than the rewiring structure and the substrate with respect to its horizontal area along the main surface. A gap is formed between the rewiring structure and the substrate, the gap being filled with the encapsulating means.

[0016] According to an exemplary embodiment, a module is provided in which one or more expensive, highly thermally conductive and electrically insulating bodies, each with very small dimensions, can be provided, thus enabling the module or package to be manufactured with minimal effort. According to such an embodiment, each thermally conductive and electrically insulating body covers only a sub-region of a main surface of a substrate, rather than substantially covering it completely. The position and dimensions of each thermally conductive and electrically insulating body on the substrate can be specifically chosen according to the position and dimensions of an electronic chip or component that acts as a heat source during the module's operation.Specifically, the relevant electronic chip or component can be mounted directly vertically above the thermally conductive and electrically insulating body, and thus at a very small distance from it. As a result, in a vertical projection, the chip or component can be aligned with or flush with a portion of the respective body. Conversely, in surface areas of the substrate not covered by a thermally conductive and electrically insulating body, preferably no chips or components are present in a vertical projection or view. An inexpensive encapsulating material can then fill any remaining gaps or spaces within the module by encapsulating the aforementioned components, essentially without leaving any cavities within the module.During operation of the module, the thermally conductive and electrically insulating body(s) can efficiently contribute to dissipating heat from a heat source(s) in the form of one or more electronic chips and / or one or more components of the package. Due to the described geometric arrangement of the thermally conductive and electrically insulating body(s) spatially very close to and limited to the areas of significant heat generation, such heat can be efficiently dissipated from the heat source and distributed via the body and the substrate to an outer surface of the module.Since the material of one or more thermally conductive and electrically insulating bodies is dielectric, its selective presence in areas of high electric field strength simultaneously ensures high electrical performance of the module. A rewiring structure located between the body(s) and the chip / component can efficiently organize electrical coupling (connection) of the chip / component to an exterior surface of the module. Description of further exemplary embodiments

[0017] In the context of the present application, the term "electronic chip" may in particular mean a chip (specifically a semiconductor chip) that provides an electronic function. The electronic chip may be an active electronic component. In one embodiment, the electronic chip is configured as a controller chip, a processor chip, a memory chip, a sensor chip, or a microelectromechanical system (MEMS). In an alternative embodiment, it is also possible for the electronic chip to be configured as a power semiconductor chip.Thus, the electronic chip (such as a semiconductor chip) can be used for power applications, for example in the automotive industry, and can, for example, contain at least one integrated insulated-gate bipolar transistor (IGBT) and / or at least one other type of transistor (such as a MOSFET, a JFET, etc.) and / or at least one integrated diode. Such integrated circuit elements can be made using silicon technology or are based on wide-bandgap semiconductors (such as silicon carbide, gallium nitride, or gallium nitride on silicon). A semiconductor power chip can include one or more field-effect transistors, diodes, inverter circuits, half-bridges, full-bridges, drivers, logic circuits, other devices, etc.

[0018] In the context of the present application, the term "component" may, in particular, mean any electronic element that performs an electronic function in the package when mounted on the substrate. Specifically, the component may be a passive component, such as a capacitance, an inductor, or a resistor. However, it is also possible for the component to be an active component.

[0019] Further exemplary embodiments of the modules and the method will be explained below.

[0020] In one embodiment, the thermally conductive and electrically insulating body is made of a material that has a thermal conductivity (heat conductivity) of at least 20 W / mK. For example, the thermal conductivity of the thermally conductive and electrically insulating body can be in a range between 20 W / mK and 200 W / mK.

[0021] In alternative embodiments, the thermally conductive and electrically insulating body can be made of a material that has a thermal conductivity of less than 20 W / mK in conjunction with a thickness of less than 150 µm.

[0022] For example, the thermal conductivity of the thermally conductive and electrically insulating body can be in a range between 20 W / mK and 150 W / mK and can include (have) or consist of a ceramic polymer matrix. For example, the thickness of the thermally conductive and electrically insulating body can be in a range between 20 µm and 150 µm, especially if it includes or consists of a ceramic polymer matrix.

[0023] In one embodiment, the encapsulating means forms at least part of a lateral (side) side wall of the module, preferably the entire side wall of the module. Accordingly, a lateral surface (side face) of the module can be formed partially or completely from the encapsulating means. The encapsulating means can thus form not only part of a main upper surface of the module, but also at least part of the side walls. This eliminates the need for a separate element forming the side walls of the package, allowing the module to be manufactured in a compact and simple manner.

[0024] In one embodiment, at least 5%, in particular at least 20%, and in particular at least 50%, of a surface area of ​​a major surface of the carrier facing the thermally conductive and electrically insulating body (or bodies) remains free of the thermally conductive and electrically insulating body(s). Thus, a substantial surface area of ​​the carrier can remain exposed and uncovered by the expensive thermally conductive and electrically insulating material of the one or more thermally conductive and electrically insulating bodies. This measure allows the expensive thermally conductive and electrically insulating material to be specifically limited to those areas where a significant amount of heat is generated and a high electric field strength is present during the operation of the package, i.e., during normal operation.h. directly below one or more electronic chips / components.

[0025] In one embodiment, the electronic chip is configured as a power chip, and the module is configured as a power module. Since both the heat dissipation capacity and the electrical robustness of the module are highly efficient due to the combination of the thermally conductive and electrically insulating body on the one hand, and the substrate on the other, it is possible to implement electronic chips in the module that are power semiconductor chips, i.e., chips that generate a considerable amount of heat during operation and can operate at high current levels. Given the heat dissipation, heat distribution, and electrical robustness achieved, it is thus possible to manufacture the module with high reliability, even when high currents and high electrical power are present in the one or more power semiconductor chips.

[0026] In one embodiment, the support is configured as a support plate. Such a support plate can essentially form the entire lower main surface of the module, thereby enabling highly efficient heat dissipation. Thus, the support can not only serve as a mounting base for the thermally conductive and electrically insulating body(ies) on one of its main surfaces, but can also—on a contrasting main surface of the support—form an outer surface of the module or package that contributes to heat dissipation.

[0027] In one embodiment, the support is made of a thermally and electrically conductive material, such as a metal (for example, copper or aluminum). For instance, the support can be designed as a metal plate, particularly a copper or aluminum plate. This allows the module to be manufactured with very little effort and cost, while still guaranteeing efficient heat dissipation.

[0028] In one embodiment, the support forms part of an outer surface of the module, in particular essentially a main surface of the module. This allows heat dissipation via the support over a large area and thus very efficiently. This makes the module reliable even in applications that generate a considerable amount of heat, for example, power semiconductor applications.

[0029] Preferably, the support can be a metal plate. Alternative supports that can be used for other embodiments can be a substrate, an IMS (insulated metal substrate), a PCB (printed circuit board), etc.

[0030] In one embodiment, the encapsulating agent comprises at least one component from the group consisting of a mold compound and a laminate. In a preferred embodiment, the encapsulating agent is a mold compound. A plastic or ceramic material can be used for encapsulation by molding. The encapsulating agent can be an epoxy material. Filler particles (for example, SiO2, Al2O3, Si3N4, BN, AlN, diamond, etc.), for example, to improve thermal conductivity, can be embedded in an epoxy-based matrix of the encapsulating agent.

[0031] In one embodiment, the encapsulating means forms at least a portion (for example, at least 70% or at least 80%) of a major surface of the module. In particular, the encapsulating means can substantially form an upper major surface (for example, only very small electrical contacts may be provided on this major surface in addition to the encapsulating means), while a lower major surface of the module is substantially formed by the support. This allows the encapsulating means to form the side wall and at least a portion of an upper major surface of the module, thus significantly contributing to defining or delimiting the outline or contour of the module. This eliminates the need for additional elements to define such an outline. Consequently, a highly compact and easily manufactured module can be obtained.

[0032] In one embodiment, the module features at least a partially electrically conductive rewiring structure (redistribution structure) between the thermally conductive and electrically insulating body on the one hand and the electronic chip / component on the other. Such a (for example, metallic) rewiring structure can be located vertically between the electronic chip(s) / component(s) and the thermally conductive and electrically insulating body(s) and can function as an element for distributing electrical signals. While the thermally conductive and electrically insulating body ensures electrical insulation between an outer surface of the module on the one hand and the one or more electronic chips / components on the other, the rewiring structure performs the function of electronic redistribution (within) the module.The rewiring structure can be embedded in the encapsulation medium and can be connected to internal and / or external electrically conductive contact structures to enable electrical communication between the interior of the module and an electronic periphery of the module.

[0033] According to the invention, the rewiring structure is configured as one or more rewiring plates, in particular one or more patterned (structured) rewiring plates. For example, such a rewiring plate can be a perforated (punched) or etched metal plate, such as a copper plate. This allows the routing and management of the signal supply to or from the one or more electronic chips / components into the interior of the module through the rewiring structure with minimal effort and high flexibility for a circuit designer. Furthermore, a plate-like configuration of the rewiring structure ensures a compact module design.

[0034] In one embodiment, the rewiring structure comprises at least two rewiring elements that are at least partially vertically spaced apart. Preferably, the rewiring structure can be configured such that, during operation of the package, current flow paths through the vertically spaced rewiring elements can be antiparallel or bidirectional. As a consequence of the described multi-level design of the rewiring structure, the parasitic inductance of the rewiring structure can advantageously be very low.

[0035] In one embodiment, the rewiring structure extends entirely within the encapsulation means, where it can be electrically coupled to electrically conductive contact structures. The rewiring structure within the interior of the encapsulation means can be electrically connected to one or more electronic chips / components via internal electrically conductive contact structures. External electrically conductive contact structures extending out of the encapsulation means can, in turn, be electrically coupled to the rewiring structure.

[0036] In one embodiment, the rewiring structure is essentially X-shaped with a central plate area. The X-shape of the rewiring structure allows for the spatial separation of the module's external contacts, thus ensuring compatibility with larger electronic environments. For example, electrical power connections or current terminals of the module can be located at the four ends of the X-shaped structure. Furthermore, the tapered geometry of the rewiring structure in the central plate area of ​​the essentially X-shaped structure enables the compact mounting of electronic chips / components.

[0037] In one embodiment, the thermally conductive and electrically insulating body is made of a ceramic material; for example, it can consist of a highly thermally conductive ceramic material such as silicon nitride, aluminum nitride, etc. Direct copper bonding (DCB) substrates, direct aluminum bonding (DAB) substrates, etc., can also be used as the thermally conductive and electrically insulating body.

[0038] In one embodiment, the module comprises at least one further thermally conductive and electrically insulating body, which is mounted on only a further portion of the main surface of the carrier. This further thermally conductive and electrically insulating body can be spaced apart from the first thermally conductive and electrically insulating body, such that a portion of the main surface of the carrier within the module remains free of highly thermally conductive and electrically insulating material. The module can additionally include a component, in particular another electronic chip, which is mounted on the rewiring structure and above the further thermally conductive and electrically insulating body. According to such an embodiment, several thermally conductive and electrically insulating bodies can be mounted on one and the same carrier, preferably all of which support the rewiring structure described above.Thus, the presence of thermally conductive and electrically insulating bodies can be limited to those areas of the module where they are actually needed, given their dielectric function and their ability to efficiently dissipate heat from the electronic chips / components to an exterior surface of the module. Instead of providing one large thermally conductive and electrically insulating body that covers the entire surface of the substrate or forms a substantial portion of a major internal surface of the module, multiple thermally conductive and electrically insulating bodies with strictly limited dimensions, corresponding to the mounting areas of the multiple electronic chips / components, can be provided.Instead of being designed as another electronic chip (as another semiconductor power chip), the component in question can also be a passive component, such as a capacitor or the like.

[0039] In one embodiment, the module has at least one internal electrically conductive contact structure, which is (preferably completely) encapsulated by the encapsulation means, in particular at least one by a bond wire and a ribbon bond. The internal electrically conductive contact structure can connect the at least one electronic chip to the rewiring structure and / or the at least one electronic chip to the at least one component. The internal electrically conductive contact structure can also connect the at least one component to the rewiring structure. Furthermore, the internal electrically conductive contact structure can connect multiple electronic chips to each other and / or multiple components to each other.Such an internal electrically conductive contact structure, which preferably does not extend to the surface of the package, can be designed, for example, as bond wires and / or ribbon bonds that connect the interior of the module. The formation of the internal electrically conductive contact structures can be carried out before encapsulation and after the mounting of the one or more electronic chips and the one or more electronic components onto the rewiring structure.

[0040] In one embodiment, the module has at least one external electrically conductive contact structure extending beyond the encapsulation means and electrically connecting the electronic chip and / or component to an electronic environment. The one or more external electrically conductive contact structures can be electrically conductive bodies attached to the rewiring structure to form electrical contacts extending beyond the encapsulation means to an outside surface of the module. They can also be connected to the electronic chip(s), component(s), etc. Electrical signals can be supplied to or routed out of the package from the electronic chips / components through such contacts.

[0041] In one embodiment, the at least one external electrically conductive contact structure comprises at least one electrically conductive sleeve (socket) with a cavity configured to receive an electrically conductive pin. The sleeve can be embedded in the encapsulating material and can contact the electronic chips and / or the rewiring structure. If the flow of encapsulating material into the cavities of the sleeves is prevented (for example, by foil molding), it is possible to easily insert electrically conductive pins into the cavities after encapsulation, thereby providing external pin contacts with minimal effort. Such sleeve-pin assemblies can serve as signal connections that transmit signals during module operation.In contrast, electrical power can be transported to one or more electronic chips / components via one or more other external electrically conductive contact structures. The latter can be embodied as bulky conductors attached to the free ends of an essentially X-shaped rewiring structure.

[0042] In one embodiment, the method involves mounting the thermally conductive and electrically insulating body(s) onto the substrate by soldering. However, as an alternative to soldering, the connection can also be made by sintering, bonding, etc.

[0043] In one embodiment, the method involves mounting one or more electronic chips / components onto the rewiring structure by soldering. This soldered connection between the electronic chip and the thermally conductive and electrically insulating body, or between the electronic chip / component and the rewiring structure, can alternatively be achieved by sintering or electrically conductive bonding.

[0044] In one embodiment, the method involves forming the aforementioned at least one external electrically conductive contact structure on the rewiring structure for electrically connecting the electronic chip to an electronic environment, and subsequently partially encapsulating the at least one external electrically conductive contact structure, so that it extends beyond the encapsulation medium, using a film mold. The film mold ensures that the one or more external electrically conductive contact structures are not covered by electrically insulating material of the encapsulation medium. This would render the one or more external electrically conductive contact structures unsuitable for fulfilling their function of electronically contacting the electronic chip / component with respect to an electronic periphery of the module.To achieve this, one or more films (e.g., adhesive ones) can be placed on the portions of the external electrically conductive contact structures that should remain free of the encapsulation material during encapsulation. After encapsulation, the films can be removed from the external electrically conductive contact structures, which therefore remain uncovered by the encapsulation material.

[0045] In various embodiments, the module or package can be configured as a half-bridge, a cascode circuit, a circuit consisting of a field-effect transistor and a bipolar transistor connected in parallel, or a power semiconductor circuit. Therefore, the packaging architecture, according to exemplary embodiments, is compatible with the requirements of very different circuit concepts.

[0046] In one embodiment, the module or package is configured as one of the following: a power module connected to a leadframe, a Transistor Outline (TO) electronic component, a Quad Flat No Leads Package (QFN) electronic component, a Small Outline (SO) electronic component, a Small Outline Transistor (SOT) electronic component, and a Thin More Outline Package (TSOP) electronic component. Therefore, according to one exemplary embodiment, the package is fully compatible with standard packaging concepts (in particular, fully compatible with standard TO packaging concepts) and appears externally as a conventional electronic component, making it very user-friendly. In one embodiment, the package is configured as a power module, e.g., a molded power module.For example, an exemplary embodiment of the electronic component could be an intelligent power module (IPM).

[0047] A semiconductor substrate, preferably a silicon substrate, can be used as the substrate or wafer that forms the basis of the electronic chips. Alternatively, a silicon oxide or another insulator substrate can be provided. It is also possible to implement a germanium substrate or a III-V semiconductor material. For example, exemplary embodiments can be implemented using GaN or SiC technology. A semiconductor device according to an exemplary embodiment can be configured as a microelectromechanical system (MEMS), sensor, etc.

[0048] Furthermore, exemplary embodiments utilize standard semiconductor processing technologies, such as suitable etching technologies (including isotropic and anisotropic etching technologies, in particular plasma etching, dry etching, wet etching), patterning technologies (which may involve lithographic masks), deposition technologies (such as chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), sputtering, etc.).

[0049] The above and other objectives, features and advantages of the present invention will become apparent from the following description and the attached claims when these are considered in conjunction with the attached drawings, in which identical parts or elements are designated by the same reference numerals. Brief description of the drawings

[0050] The accompanying drawings, which are included to provide a further understanding of exemplary embodiments and which form part of the description, illustrate exemplary embodiments.

[0051] The following applies to the drawings: Fig. 1 to Fig. Figure 7 shows three-dimensional views of intermediate structures obtained during the execution of a method for manufacturing a power module according to an exemplary embodiment. Fig. Figure 8 shows a three-dimensional view of a performance module created by executing the following with reference to Fig. 1 to Fig. The method described in section 7 was produced according to an exemplary embodiment. Fig. Figure 9 shows a cross-sectional view of a power module according to an exemplary embodiment. Fig. Figure 10 shows a three-dimensional view of a rewiring structure composed of different vertically spaced layers of a module according to a further exemplary embodiment. Fig. Figure 11 shows a three-dimensional view of a preform of a module during manufacturing according to the embodiment of Fig. 10 before encapsulation.

[0052] This falls under the category Fig. 10 and Fig. Module 11 described does not fall under the claims of the application. Detailed description of exemplary embodiments

[0053] The representation in the drawing is schematic.

[0054] Before further exemplary embodiments are described in more detail, some general considerations of the current inventors are summarized on the basis on which exemplary embodiments have been developed.

[0055] To manufacture a module or package of an exemplary embodiment in a compact and cost-effective manner, without compromising electrical and thermal reliability, it is possible to provide a small-dimensioned, highly thermally conductive and electrically insulating body (comprising, for example, silicon nitride) that is restricted to high-power areas of the module to improve its heat dissipation and electrical performance. To minimize the manufacturing effort of the package, it is possible to restrict the provision of the at least one thermally conductive and electrically insulating body to a spatial region of the module where it is actually needed (i.e., areas subject to high thermal stress and high electric field strength).

[0056] In accordance with the foregoing, an exemplary embodiment provides a module in which a module frame, encapsulation, and filling of cavities around a minimal substrate (i.e., the one or more thermally conductive and electrically insulating bodies) can be carried out in a single, combined operation. A thermally efficient, thermally conductive, and electrically insulating body (made, in particular, of a ceramic material) is implemented only in areas of highest performance or power density (especially beneath one or more electronic chips and / or electronic components, preferably exclusively there). Remaining cavities of the module can be filled with an inexpensive material, in particular a mold compound or other encapsulating agent.

[0057] The measures described make it possible to produce a highly efficient, compact and easily manufactured power semiconductor module.

[0058] By reducing the implementation of a ceramic material to one or more areas of highest power density, it is also possible to use manufacturing processes such as laser sintering for the thermally conductive and electrically insulating body(ies). Furthermore, the use of an encapsulating agent, such as a mold compound, reduces the complexity of the manufacturing processes and keeps the number of module components to a minimum.

[0059] In one embodiment, a module (e.g., DCB (Direct Copper Bonding) or IMS (Intermetallic Substrate)-free) can be provided with a minimally sized or at least spatially confined thermally conductive and electrically insulating body. The one or more highly thermally conductive and electrically insulating bodies can be located exclusively in areas below the one or more electronic chips and / or electronic components. Thus, the thermally conductive and electrically insulating body can be smaller, in particular significantly smaller, than the upper and lower surfaces of the module. Nevertheless, the entire main surface area of ​​the module can be used for electrical rewiring and heat dissipation.Areas between the layers (including a rewiring structure and a plate-like support) can be filled with an encapsulating material, such as an epoxy resin-based mold compound. The encapsulation can therefore define a significant portion of the outline or contour of the fabricated module. This again eliminates the need for separate outline or contour-defining components. The fabrication of the module frame, encapsulation, and filling of cavities around a minimal substrate (i.e., the one or more thermally conductive and electrically insulating bodies) can be accomplished in a common, simple, and compact manufacturing process.

[0060] Furthermore, a support (such as a support plate or a beam shaped in another way) can be defined as an integral part of the module, i.e., it forms part of the layer stack. This eliminates the need for a separate base plate compared to conventional modular constructions.

[0061] In one embodiment, it is also possible to configure parts (such as layers or plate sections) of the rewiring structure in a three-dimensionally shaped manner, so that different sub-areas of the rewiring structure can be arranged vertically spaced (in particular parallel) to each other. This measure can reduce the parasitic inductance of the module, which further improves the module's electrical performance. In other words, an electric current can be guided antiparallel (bidirectionally) through the different layers of the rewiring structure, which reduces the net inductance.

[0062] According to one exemplary embodiment, a module (particularly without a separate base plate) is provided that is based on a minimal substrate approach, i.e., only a very small surface of a support is covered by one or more thermally conductive and electrically insulating bodies. In one embodiment, a support frame and an encapsulation means (which can be formed separately in a conventional manner) can be formed, at least partially, as a single, combined structure.

[0063] Fig. 1 to Fig. Figure 7 shows three-dimensional views of intermediate structures obtained during the execution of a method for manufacturing a power module 100 according to an exemplary embodiment.

[0064] With reference to Fig. Figure 1 illustrates a support 102, which serves as a base for the fabrication of the module 100. In the embodiment shown, the support 102 is configured as an electrically conductive carrier plate, made, for example, of a metal such as copper. Preferably, the material of the support 102 is thermally conductive to contribute appropriately to the heat dissipation from the module 100 during operation. In the finished module 100, the support 102 forms part of an outer surface of the module 100 and can even substantially constitute a main surface 130 of the module (see Figure 1). Fig. 9).

[0065] Fig. Figure 1 therefore shows the support 102 as a base plate that forms an interface for external cooling of the module 100 during manufacturing. The support 102 can be manufactured as a planar copper plate. Another embodiment of the support 102 is an AlSiC plate, which may be equipped with projecting ribs (pin fins) and sealing grooves on its underside. The main surface 128 of the support 102 facing the interior of the module may preferably be made of a material capable of forming a thermally conductive and electrically insulating body 104 (see Figure 1). Fig. 2) to be joined by soldering. Furthermore, it is advantageous that the carrier 102 is made of a material that provides a suitable adhesive interface for a mold joint or other encapsulation means 108. However, it is also possible that the adhesion of a mold joint is promoted by an appropriate surface treatment of the carrier, for example, a surface treatment with an adhesion promoter.

[0066] With reference to Fig. Figure 2 shows a structure in which two separate rectangular, plate-like, thermally conductive and electrically insulating bodies 104 are mounted by soldering onto only a portion of a main surface 128 of a support 102. Thus, a portion of the upper main surface 128 of the support 102 remains uncovered by the bodies 104. The uncovered portion can, for example, comprise at least 10%, preferably more than 20%, of the total surface area of ​​the main surface 128.

[0067] The thermally conductive and electrically insulating bodies 104, which can also be referred to as insulating elements, can be mounted on the support 102, which can serve as an integral lower plate of the module 100 during manufacturing. The bodies 104 can also function as spacers. For example, the bodies 104 can be made of a silicon nitride ceramic material with a thermal conductivity of, for example, approximately 90 W / mK. However, it is also possible to use ceramic materials such as Al₂O₃, AlN, BN, ZTA (zirconium dioxide-reinforced alumina, zirconia-toughened alumina), or a ceramic / polymer composite material.

[0068] The shape and dimensions of the insulating elements or bodies 104 can be adapted based on the following two criteria. A first criterion is to select them in such a way as to allow for the most efficient use of the surface area. A second criterion is to select the dimensions of the bodies 104 so that they cover the most intense heat-distributing area under the electronic chips 106 and the electronic components 114 that are to be mounted later (see Fig. 4) cover. Furthermore, it is advantageous if the bodies cover 104 areas where the mechanical force is high during the assembly process. Typically, these areas are the wire bonding areas and / or areas of welding connections (see Fig. 5, Fig. 6) It is advantageous to keep the bodies 104 as small as possible in order to minimize the effort required to manufacture the module 100.

[0069] However, it is also possible to produce the bodies 102 additively on the substrate 102. For example, this can be done by depositing the appropriate material, for instance, using 3D printing, stencil printing, or screen printing. It is also possible to apply in-situ laser sintering or pressure-assisted sintering at a temperature below the melting point of the copper material of the substrate 102. One advantage of implementing an additive material in this context is that it allows for a design with higher degrees of freedom and enables improvements in terms of the production area of ​​a plate or panel.

[0070] Several embodiments for connecting the bodies 104 to the support 102, in particular the formation of a ceramic-metal connection, are described below.

[0071] In a corresponding embodiment, the insulating elements or bodies 104 are covered on both opposing main surfaces with a soldering material, for example, a silver solder. Such a material can be applied by screen printing and can be stabilized by a drying process while maintaining a rubber-like consistency. This makes it possible to cover even large plates or panels, which can later be separated into individual modules or parts thereof. In such a state, the carrier 102, the bodies 104, and a rewiring structure 112 (see Fig. 3) The components are joined by soldering in a vacuum furnace at a temperature of 400 °C. The addition of a protective gas atmosphere or a reducing atmosphere prevents unwanted oxidation of the components of Module 100 or the joining materials. Temperature-resistant guide elements, which can exert pressure on the layer stack, prevent unwanted slippage of the individual components. This results in a more reliable Module 100. The formation of unwanted voids or similar defects can also be prevented. Subsequently, the resulting structure can be chemically treated. This allows for the removal of excess solder material that may have accumulated as a result of the previous processes. In particular, this ensures that the side walls of the ceramic material are free of unwanted solder material.It is also possible to clean or scrub the copper surface, roughen the copper surface and deoxidize the copper surface in order to prepare the surface of the support 102 in a suitable manner for adhesion of a mold compound or other encapsulating agent 108 (see . Fig. 7) prepare. Sensitive areas of the carrier 102 can be covered during this chemical preparation process, for example by using a mounting element or a holder in conjunction with a sealing lip.

[0072] As an alternative for connecting the carrier 102 and the bodies 140, it is also possible to use AlSi as the soldering material. It is possible to replace a silver solder with AlSi3-5.

[0073] Another alternative is to solder the bodies 104 to the copper carrier 102 using an AMB (active metal braze) solder (for example, with a silver content greater than 30%, at a temperature above 600 °C).

[0074] In yet another embodiment, it is possible to bond the ceramic material of the bodies 104 to the support 102 at a temperature above 1065 °C. In this embodiment, it is possible to pre-oxidize the oxygen-bearing layers involved.

[0075] According to yet another embodiment, it is possible to connect the polymer-ceramic composite material of the bodies 104 directly to a roughened support 102 (especially made of copper) by means of its polymer content, for example by means of lamination under pressure.

[0076] With reference to Fig. 3. An electrically conductive rewiring structure 112 is mounted on the thermally conductive and electrically insulating bodies 104 and on the support 102, projecting beyond the bodies 104 and the support 102 in the form of free end regions 175. In the described embodiment, the rewiring structure 112 is configured as a patterned (structured), metallic rewiring plate. The rewiring structure 112 is essentially X-shaped with a central plate section 173 from which the four free end regions 175 extend laterally outwards. This central plate section 173 of the rewiring structure 112 is mounted on the bodies 104 and the support 102, whereas the four free end regions 175 of the rewiring structure 112 extend laterally beyond the support 102.

[0077] With reference to Fig. 3. The rewiring structure 112 can be placed on the insulating elements or bodies 104. For example, the rewiring structure 112 can be a perforated copper plate. During the assembly process, it is possible to connect galvanically isolated areas later using a guide frame to hold them in position.

[0078] The three manufacturing processes mentioned above can be carried out at one manufacturing site.

[0079] With reference to Fig. 4. Several electronic chips 106 (such as active semiconductor chips) are mounted by soldering onto the rewiring structure 112 and directly vertically above one of the thermally conductive and electrically insulating bodies 104. Furthermore, a plurality of other electronic components 114 (such as passive components like capacitors) are mounted by soldering onto the rewiring structure 112 and directly vertically above another of the thermally conductive and electrically insulating bodies 104. For example, the components 114 can be passive electronic components (such as thermal resistors, shunts, ohmic resistors, inductors (coils), or capacitances), they can be glass chips for module traceability, or they can be other electronic chips 106 (such as driver chips).Specifically, the sizes and positions of the bodies 104 are chosen to correspond to or be flush with the positions of the electronic chips 106 and the components 114. As a result, the expensive, highly thermally conductive bodies 104 need only be placed at the locations of the heat-generating electronic chips 106 and components 114, thereby contributing to heat distribution and dissipation during the operation of the module 100. This position also corresponds to a position of maximum electric field strength, so the bodies 104 also enhance the electrical robustness of the module 100. Thus, the described manufacturing method is particularly advantageous when the electronic chips 106 are configured as semiconductor power chips and the module 100 is configured as a power module.Such power semiconductor chips may contain integrated circuit elements, such as insulated gate bipolar transistors and / or diodes.

[0080] The assembly process of the electronic chips 106 and the components 114 can be completed by soldering. Other processes, such as sintering, are also possible.

[0081] With reference to Fig. 5 External electrically conductive contact structures 118 are formed (extending beyond the subsequently formed encapsulating means 108 and) which connect the electronic chips 106 and the components 114 to an electronic environment. The external electrically conductive contact structures 118 have electrically conductive sleeves 120, each of which has a cavity 134 and which are designed to receive an electrically conductive pin 122 (compare Fig. 8 and Fig. 9) are configured. The external electrically conductive contact structures 118 also have massive or voluminous conductors 171, which are attached to the end regions 175 of the rewiring structure 112.

[0082] How Fig. As can be seen from Figure 5, the external electrically conductive contact structures 118 are formed on the rewiring structure 112. This can be done in conjunction with the mounting of the electronic chips 106 and the components 114 using the described soldering process. Alternatively, the external electrically conductive contact structures 118 can also be connected by ultrasonic welding. Other connection techniques are also possible. Pin sleeves 120 can be used for the signal connections. Larger threaded metal sleeves or the massive conductors 171 can be used for the electrical load contacts.

[0083] With reference to Fig. 6 Internal electrically conductive contact structures 116 are formed (which are later completely encapsulated by the encapsulating agent 108). The internal electrically conductive contact structures 116 can be designed as bond wires and / or ribbon bonds that electrically connect the electronic chips 106, the components 114, and the rewiring structure 112. Thus, the electronic chips 106, the components 114, and the rewiring structure 112 can be electrically connected to each other by aluminum or copper wires. Additionally or alternatively, ribbon bonds or sintered wire contacts can be implemented. If the external electrically conductive contact structures 118 are formed by ultrasonic welding, the wire bonding can be carried out immediately after chip assembly.

[0084] With reference to Fig. 7. A portion of the carrier 102, the thermally conductive and electrically insulating bodies 104, the electronic chips 106, the components 114, the internal electrically conductive contact structures 116, and a portion of the external electrically conductive contact structures 118 are encapsulated by an encapsulation means 108. In the embodiment shown, the encapsulation means 108 is a molded compound. The encapsulation is carried out such that the encapsulation means 108 forms the entire lateral sidewalls of the module 100.

[0085] As mentioned, the external electrically conductive contact structures 118 are only partially encapsulated by the encapsulating means 108, so that they extend beyond the encapsulating means 108, in the illustrated embodiment exclusively on an upper main surface of the module 100. This can be achieved by film molding, i.e., by temporarily covering the portions of the external electrically conductive contact structures 118 that are to be exposed later with adhesive films during the encapsulation process. Subsequently, the films are removed to expose the external electrically conductive contact structures 118 for the establishment of an electrical contact with an electronic environment and without any interfering dielectric mold connection on them.To prevent the external electrically conductive contact structures 118 from being covered with encapsulating material 108 during encapsulation, it is possible to cover these elements 118 with films during molding. A suitable film can be placed on a portion of these elements 118 and then clamped between the external electrically conductive contact structures 118 on the one hand and an encapsulation tool (such as an upper mold tool) on the other.

[0086] The support 102 also extends to a surface of the module 100, specifically forming the majority or a large part of the lower main surface 130 for efficient heat dissipation. The encapsulating medium 108 forms a large portion of an opposite main surface 132 of the module 100. The circumferential side edge of the module 100 is also essentially formed by the encapsulating medium 108. In the Fig. In the molded state shown in Figure 7, the rewiring structure 112 extends completely within the encapsulation medium 108.

[0087] Fig. Figure 7 therefore shows how the encapsulating agent 108, here designed as a mold compound, reacts with the in Fig. The intermediate product shown in Figure 6 is applied and defines a significant part of the outline or contour of the module 100 during manufacturing. During molding, the outer surface of the module 100 can be defined, the electronic chips 106 as well as the components 114 are covered, and void areas between the carrier 102 and the rewiring structure 112 can be filled.

[0088] Fig. Figure 8 shows a three-dimensional view of a power module 100, which was created by executing the function with reference to Fig. 1 to Fig. The method described in section 7 was produced according to an exemplary embodiment.

[0089] Finally, the power module 100 shown has a plate-like carrier 102 covered with spatially strictly confined plate-like, thermally conductive, and electrically insulating bodies 104. The carrier 102 and the bodies 104 are in turn covered by a single layer or a multilayer rewiring structure 112. One or more semiconductor power chips 106, optionally accompanied by one or more other components 114, are mounted on the rewiring structure 112 and directly vertically above the thermally conductive and electrically insulating bodies 104. The mold-like encapsulating means 108 encapsulates a portion of the carrier 102, the thermally conductive and electrically insulating bodies 104, the semiconductor power chips 106, and the other components 114. Both a majority ora large part of an upper main surface 132 and an entire side wall 110 of the module 100 are defined by the encapsulation means 108, while a lower main surface 130 is predominantly defined by the support 102 and partly by the encapsulation means 108.

[0090] How Fig. Once the 8 can be removed, pins 122 can be inserted into the cavities 134 of the sleeves 120. This simplifies the electrical connection between the resulting module 100 and an electronic peripheral.

[0091] Several power signals U, V, DC+, DC- and several control signals G1, G2, G3, G4, “Sense”, which are applied to the various external electrically conductive contact structures 118, are in Fig. 8 displayed.

[0092] Fig. Figure 9 shows a cross-sectional view of a power module 100 according to an exemplary embodiment.

[0093] The in Fig. Figure 9, a cross-sectional view, illustrates that the module 100 can be manufactured with an extremely compact design, i.e., a very low height. Furthermore, the manufacturing process is very simple, since a large part of the outline or contour of the module 100 is defined by the encapsulating element 108 and the support 102. The thermally conductive and electrically insulating bodies 104 are limited to areas where they are absolutely necessary for heat dissipation and electrical reliability. This measure also contributes to the simple manufacturing of the module 100.

[0094] Fig. Figure 10 shows a three-dimensional view of a rewiring structure 112, which is composed of different vertically spaced layers 177, 179, of a module 100 according to a further exemplary embodiment. Fig. Figure 11 shows a three-dimensional view of a preform of a module 100 during its manufacture according to the embodiment of Fig. 10. Fig. 10 and Fig. Figure 11 shows an embodiment of a rewiring structure 112, which is partly formed from different layers 177, 179. This measure allows a low inductance of the resulting module 100 to be achieved.

[0095] In the embodiment of. Fig. 10 and Fig. Thus, it is possible to configure the rewiring structure 112 as a multilayer structure. This has a positive effect on the inductance of the rewiring structure 112, which can be reduced by this measure. In this context, it is also possible to implement electrically insulating retaining elements as spacers (not shown) between the different layers 177, 179.

[0096] It should be noted that the term "having" (or "comprising") does not exclude other elements or features, and that the term "a", "an", "a" or "a" does not exclude a plurality. Furthermore, elements described in connection with different embodiments may be combined.

Claims

[1] A module (100) that has the following features: • a carrier (102); • a body (104) that is at least partially thermally conductive and electrically insulating, mounted on only part of a main surface (128) of the support (102); • an at least partially electrically conductive rewiring structure (112) on the thermally conductive and electrically insulating body (104); • an electronic chip (106) mounted on the rewiring structure (112) and above the thermally conductive and electrically insulating body (104); wherein the rewiring structure (112) has several structured rewiring plates that are laterally spaced and do not overlap vertically; • an encapsulation means (108) which encapsulates at least part of the carrier (102), at least part of the thermally conductive and electrically insulating body (104), at least part of the rewiring structure (112) and at least part of the electronic chip (106), • wherein the thermally conductive and electrically insulating body (104) is smaller than the rewiring structure (112) and the support (102) with respect to its horizontal area along the main surface (128), thereby forming a gap between the rewiring structure (112) and the support (102), the gap being filled with the encapsulating agent (108). [2] The module (100) according to claim 1, wherein the encapsulation means (108) forms at least a part of a lateral side wall (110) of the module (100). [3] The module (100) according to claim 1 or 2, wherein at least 50% of an area of ​​a main surface of the support (102) facing the thermally conductive and electrically insulating body (104) remains free from the thermally conductive and electrically insulating body (104). [4] The module (100) according to any one of claims 1 to 3, wherein the support (102) forms part of an outer surface of the module (100), in particular substantially forming a main surface (130) of the module (100). [5] The module (100) according to any one of claims 1 to 4, wherein the encapsulation means (108) forms at least a part of a main surface (132) of the module (100). [6] The module (100) according to any one of claims 1 to 5, wherein the rewiring structure (112) has at least two rewiring elements which are at least partially vertically spaced apart from each other. [7] The module (100) according to any one of claims 1 to 6, wherein the thermally conductive and electrically insulating body (104) is made of silicon nitride. [8] The module (100) according to any one of claims 1 to 7, comprising at least one internal electrically conductive contact structure (116) which is encapsulated by the encapsulation means (108), in particular at least one of a bond wire and a ribbon bond, and which electrically connects at least one pair of the group consisting of the electronic chip (106) with the rewiring structure (112) and the electronic chip (106) with the component (114). [9] The module (100) according to any one of claims 1 to 8, comprising at least one external electrically conductive contact structure (118) extending beyond the encapsulation means (108) and electrically connecting the electronic chip (106) to an electronic environment. [10] The module (100) according to claim 9, wherein the at least one external electrically conductive contact structure (118) has at least one electrically conductive sleeve (120) with a cavity (134) configured to receive an electrically conductive pin (122). [11] The module (100) according to any one of claims 1 to 10, wherein the thermally conductive and electrically insulating body (104) has a thermal conductivity of at least 20 W / mK, in particular at least 50 W / mK, in particular at least 80 W / mK. [12] A method for manufacturing a module (100), wherein the method comprises: • Mounting a thermally conductive and electrically insulating body (104) on only part of a main surface (128) of a support (102); • Mounting an at least partially electrically conductive rewiring structure (112) on the thermally conductive and electrically insulating body (104), • wherein the rewiring structure (112) comprises several structured rewiring plates that are laterally spaced and do not overlap vertically; • Mounting an electronic chip (106) on the rewiring structure (112) and over the thermally conductive and electrically insulating body (104); • Encapsulating at least part of the carrier (102), at least part of the thermally conductive and electrically insulating body (104), at least part of the rewiring structure (112) and at least part of the electronic chip (106) by an encapsulation means (108), • wherein the thermally conductive and electrically insulating body (104) is smaller than the rewiring structure (112) and the support (102) with respect to its horizontal area along the main surface (128), thereby forming a gap between the rewiring structure (112) and the support (102), the gap being filled with the encapsulating means (108). [13] The method according to claim 12, wherein the method comprises mounting the thermally conductive and electrically insulating body (104) onto the support (102) by means of soldering. [14] The method according to claim 12 or 13, wherein the method comprises mounting the electronic chip (106) onto the rewiring structure (112) by soldering. [15] The method according to any one of claims 12 to 14, wherein the method comprises: • Forming at least one external electrically conductive contact structure (118) that electrically connects the electronic chip (106) to an electronic environment; • only partially encapsulating the at least one external electrically conductive contact structure (118) so that it extends beyond the encapsulation means (108) by means of foil molds.

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