Method for manufacturing a metal substrate-semiconductor component assembly
By dividing the assembly into a metal substrate and an adjustable protective element, the method addresses the complexity and cost issues of existing manufacturing methods, enabling flexible and cost-effective production of semiconductor assemblies with improved mechanical protection and heat dissipation.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- SCHAEFFLER TECHNOLOGIES AG & CO KG
- Filing Date
- 2024-12-13
- Publication Date
- 2026-06-11
Smart Images
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Abstract
Description
Technical field:
[0001] The present invention relates to a method for producing a metal carrier-semiconductor component assembly, which can be used, for example, in a (power) electrical arrangement or a (power) inverter, specifically a power inverter for an electric drive system of a motor vehicle. State of the art and object of the invention:
[0002] Due to various advantages, such as shortened signal paths and protection of components from environmental influences, so-called "embedded technology" is gaining increasing popularity in various (power) electrical configurations, especially in (power) inverters, particularly for electric drive systems in motor vehicles. In this technology, (power) semiconductor devices are embedded in cavities of substrates, especially printed circuit boards, and electrically contacted via vias that pass through the substrate layer.
[0003] The German patent application DE 195 11 775 C1 describes a composite consisting of a copper foil and two stacked semiconductor chips as well as a stiffening ring, wherein the semiconductor chips and the stiffening ring are arranged on the same surface of the copper foil, and the stiffening ring surrounds the two semiconductor chips.
[0004] Document US 2017 / 0 316 994 A1 describes a composite consisting of a chip and a protective structure surrounding that chip.
[0005] To efficiently dissipate the heat generated by the (power) conductor components during operation, these components are inserted into so-called insert elements (or metal carriers, or "inlays") made of copper or a comparable metallic material, acting as heat spreaders. For this purpose, the copper insert elements are provided with recesses or indentations into which the (power) conductor components are placed and connected to the insert elements both physically and thermally, and, if required, electrically. The assemblies consisting of the insert elements or metal carriers and the (power) conductor components embedded in the recesses of these insert elements are then placed into the cavities of the carrier substrates and encased in insulating materials.
[0006] As with almost all technical components, the general requirement for the aforementioned assembly consisting of the insert element and the (power) conductor component embedded in it, or a (power) electrical arrangement, in particular a (power) inverter, with such an assembly is to design or manufacture it in a simpler and therefore more cost-effective manner.
[0007] The purpose of this application is therefore to provide a way to attach a metal support (or... Insert element)-semiconductor component assembly and thus also a (power) electrical arrangement, in particular a (power) inverter, can be manufactured more easily and cost-effectively with such an assembly. Description of the invention:
[0008] This problem is solved by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims.
[0009] According to the invention, a method for producing a metal carrier-semiconductor component assembly for a (power) electrical arrangement, in particular for a power inverter, specifically for an electric drive system of a motor vehicle, is provided.
[0010] The assembly comprises a metal substrate with a (flat) surface for mounting the elements described below. Furthermore, the assembly includes at least one (power) conductor component, which is arranged and attached to the surface of the metal substrate (directly or solely by means of a thermally and, in particular, electrically conductive connecting layer, such as a sintered or soldered layer) and is thus physically and thermally (and possibly also electrically) connected to the metal substrate.
[0011] The assembly further comprises at least one protective element, which is arranged and attached to the surface of the metal substrate (directly or solely by means of a thermally and, in particular, electrically conductive connecting layer, such as a sintered or soldered layer) and is thus physically and thermally connected to the metal substrate. This protective element forms at least a partial circumferential ring around the semiconductor device. The protective element also has a height (viewed perpendicular to the (planar) surface of the metal substrate) that is equal to or greater than the height of the semiconductor device. Specifically, the height of the protective element is slightly greater than the height of the semiconductor device, by a maximum of 5%, 10%, or 20%.
[0012] According to the procedure, the metal substrate with its (flat) surface is provided for mounting the subsequently described elements. Furthermore, the semiconductor device to be mounted on the aforementioned surface of the metal substrate is provided, and its height is measured. Based on the measured height of the semiconductor device, the required height of a protective element is determined, and a protective element with this determined height is provided. The required height of the protective element is determined or specified such that it is equal to or greater than the height of the semiconductor device. The semiconductor device and the protective element are positioned on the surface of the metal substrate and secured there. The protective element is placed on the surface, at least partially surrounding the semiconductor device.
[0013] For the step of providing the protective element, a maximum possible height (and possibly also a minimum possible height) of the semiconductor device can be predicted. Based on the predicted maximum possible height (and possibly also the predicted minimum required height) of the semiconductor device, a maximum required height (and possibly also a minimum required height) of the protective element can then be determined.
[0014] Furthermore, in the step of providing the protective element, a large number of protective elements of varying heights can be pre-produced, with the range of these different heights extending from the minimum required height to the maximum required height of the protective element. From this large number of pre-produced protective elements of varying heights, the protective element with the previously determined required height can then be selected.
[0015] To pre-produce the large number of protective elements in different heights, the protective elements can be punched or cut out or formed in a comparable separation process from a large number of semi-finished products, in particular from a large number of sheets, in different heights, the range of which extends in particular from the minimum required height to the maximum required height of the protective element.
[0016] Alternatively, the step of providing the protective element can be accomplished by stamping a pre-formed protective element blank into the protective element with the required height. For this purpose, a large number of protective element blanks are pre-formed with the uniform, previously predefined (expected) maximum required height of the protective element, as described above. The maximum required height of this large number of protective element blanks is predefined, as described above, to ensure that it is greater than the expected maximum height of the semiconductor device (taking into account the largest possible manufacturing tolerances of the semiconductor device).To provide the protective element with the previously determined required height, a protective element blank (with the predetermined maximum required height) is taken from the multitude of protective element blanks (with the predetermined maximum required height) and embossed or pressed up to the determined required height and thus to the height required for the protective element.
[0017] The semiconductor component and the protective element selected as described above can then be attached or fastened to the surface of the metal substrate in the same joining process and with the same joining technique, in particular sintered or soldered onto the surface of the metal substrate in the same sintering process or in the same soldering process.
[0018] Alternatively, the semiconductor component and the protective element can be attached or fastened to the surface of the metal substrate one after the other in two joining processes and / or using different joining techniques.
[0019] The "heat spreader" for dissipating waste heat from the (power) conductor component thus has two components, namely: - the metal support as a basic heat sink for dissipating the waste heat, and - the protective element for protecting the semiconductor component from external mechanical influences, in particular from vertical pressure loads acting on the semiconductor component, wherein the protective element can be selected or provided variably in its vertical height or thickness.
[0020] By dividing the "heat spreader" into the two aforementioned components, the assemblies can be flexibly and cost-effectively adapted to semiconductor devices of various designs, particularly in terms of height, and thus also to those from different semiconductor device manufacturers. This is achieved by simply adapting the protective element to the semiconductor device, while the metal carrier, as the base body, can be manufactured uniformly and therefore cost-effectively. The protective element, a cost-effective sheet metal part, can be pre-produced in various designs and selected according to the properties and / or height of the semiconductor device.
[0021] Accordingly, the system can be adapted more flexibly and cost-effectively to the various designs, types, and requirements of semiconductor components from different manufacturers. Furthermore, the manufacturing tolerances of semiconductor components can be compensated for more easily.
[0022] This provides a way to manufacture a metal substrate-semiconductor component assembly, and thus also a (power) electrical arrangement, especially a (power) inverter, with such an assembly more easily and cost-effectively.
[0023] The protective element and the semiconductor component can be sintered or soldered onto the surface of the metal substrate, especially in the same sintering or soldering process.
[0024] The protective element and the metal support can be made of the same material. In particular, the protective element and the metal support can be made of copper or the same copper alloy.
[0025] The protective element can be U-shaped or C-shaped (with square or rounded edges) or ring-shaped or polygonal ring-shaped, in particular square ring-shaped, and thus enclose the semiconductor device on at least three sides.
[0026] Alternatively, the protective element can be formed in an I-shape, in which case the assembly has at least two protective elements (of this I-shape) distributed on two opposite sides of the semiconductor device and thus enclosing the semiconductor device at least on its two sides.
[0027] Furthermore, an electrical, in particular a power electrical, arrangement is provided.
[0028] The arrangement comprises (at least) one circuit carrier, in particular in the form of a printed circuit board, which has a cavity. The arrangement further comprises (at least) one previously described metal carrier-semiconductor component assembly, which is arranged in the cavity of the circuit carrier.
[0029] The arrangement can have spaces in the cavity between the composite arranged in the cavity and the cavity wall, which are filled with an electrically insulating material, in particular a molding compound or a resin material.
[0030] In addition, an inverter, in particular a power inverter, e.g. for an electric drive system of a motor vehicle, is provided.
[0031] The (power) inverter has a cooler with a cooling surface and (at least) a previously described (power) electrical arrangement with (at least) a compound described above, which is arranged on the cooling surface of the cooler and thermally connected to it. Brief description of the drawings:
[0032] Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 in a schematic cross-sectional view a section of a metal carrier-semiconductor component assembly according to an exemplary embodiment of the invention; and Fig. 2 in a further schematic cross-sectional representation a section of a power electrical arrangement with a composite of Fig. 1; Fig. 3. In a schematic diagram, a method for producing a composite from Fig. 1. Detailed description of the drawings:
[0033] Fig. Figure 1 shows a schematic cross-sectional view of a metal carrier-semiconductor component assembly VB according to an exemplary embodiment of the invention.
[0034] The composite VB has a metal support MT made of copper or a copper alloy, which is cuboid or plate-shaped and has a flat surface OF, which serves for mounting elements to be described below.
[0035] The VB assembly further comprises a semiconductor device HB in the form of a bare chip, which has a top-side load current connection area, a top-side signal connection area, and a bottom-side load current connection area. The bottom-side load current connection area is (directly) arranged on the surface OF of the metal substrate MT, or is merely sintered onto the surface OF by means of a sintered compound layer SV. The bottom-side load current connection area provides thermal and electrical contact between the semiconductor device HB and the metal substrate MT.
[0036] The semiconductor device HB is formed, for example, as a Si (silicon-based), a SiC (silicon carbide-based), or a GaN (gallium nitride-based) semiconductor device.
[0037] The VB assembly also features a protective element SE, which is made of the same material as the metal substrate MT, i.e., copper or a copper alloy, and is arranged (directly) on the same surface OF of the metal substrate MT as the semiconductor device HB, or is also sintered onto the surface OF by means of a sintered compound layer SV. The protective element SE is shaped as a rectangular ring-shaped plate, and the semiconductor device HB is formed or positioned around its three sides. Furthermore, the protective element SE has a height H2 that is equal to the height H1 of the semiconductor device HB or is at most approximately 10% greater (of the height H1 of the semiconductor device HB) than the height H1 of the semiconductor device HB.
[0038] The protective element SE can also be I-shaped instead of square ring-shaped. In this case, the assembly VB has two, three, or four I-shaped protective elements SE, which are placed around the semiconductor device HB on its two, three, or four (mutually opposite) sides, thus distributing the semiconductor device HB around its circumference.
[0039] The functionalities of the VB system, in particular the metal support MT and the protective element(s) SE, are explained below. Fig. 2 described in more detail.
[0040] Fig. Figure 2 shows a section of a power electrical arrangement EA with a composite VB in a further schematic cross-sectional view. Fig. 1.
[0041] The arrangement EA features a multilayer printed circuit board (PCB) LP as a circuit carrier, which has a cavity KV spanning multiple layers. A previously described metal substrate-semiconductor assembly VB is embedded in the cavity. Between the assembly VB and the cavity KV's surrounding structure, the PCB LP has spaces filled with an electrically insulating resin material HM, such as epoxy resin.
[0042] The printed circuit board LP has several insulating layers IL, e.g. made of glass fiber reinforced epoxy resin, as well as several adjacent, structured copper layers, whereby the copper layers form conductor tracks LB of the printed circuit board LP for transmitting load currents and signals.
[0043] The printed circuit board (PCB) also features several electrically conductive vias (VS) that extend from the respective conductor tracks (LB) through corresponding insulation layers (IL) to the metal substrate (MT) or the semiconductor device (HB) of the embedded composite (VB). These vias electrically connect the corresponding conductor tracks (LB) to the upper load current connection area, the upper signal connection area, and, via the metal substrate (MT), to the lower load current connection area. The vias (VS) connected to the metal substrate (MT) also serve as thermal vias for dissipating heat from the metal substrate (MT) or the semiconductor device (HB).
[0044] The arrangement EA can include, in addition to the connected VB(s), a control circuit (not shown in detail in the figure) for controlling the semiconductor device(s) HB, which can be formed on or in the printed circuit board LP or on an outer or inner layer of the printed circuit board LP.
[0045] The printed circuit board (PCB) LP, together with the embedded assembly VB (usually with several e-assemblies VB embedded in multiple cavities KV of the PCB LP) and the circuit formed in or on the PCB LP, forms part of a power inverter, e.g., an electric drive for a motor vehicle. In addition to the previously described arrangement EA, the power inverter may also have a heat sink with a cooling surface, in which case the arrangement EA, or its PCB LP, can be positioned on the cooling surface of the heat sink of the power inverter via its (unpopulated) underside and thermally connected to it.
[0046] Because the protective element SE encloses the semiconductor device HB and because the protective element SE extends beyond the semiconductor device HB at its height H1 and thus in its vertical extent, the protective element SE withstands pressure loads that act on the protective element SE and the semiconductor device HB during the manufacture of the arrangement EA, in which the assembly VB together with the protective element SE and the semiconductor device HB is inserted into the cavity KV of the printed circuit board LP and encased with the insulating resin material HM, and thus protects the semiconductor device HB from damage caused by these pressure loads.
[0047] The following will be described using a Fig. The diagram 3 schematically illustrates a method for producing a previously described composite VB: First, a metal carrier MT with a flat surface OF is provided according to step S100. The metal carrier MT can be punched, cut, or separated from a first sheet of copper or a copper alloy using a comparable separation process. If necessary, for example in the case of an uneven surface, a metal carrier roll separated from the sheet as described above can be reworked, for example by embossing, to flatten its surface OF and also its underside for subsequent surface contacts.
[0048] Furthermore, according to step S200, a semiconductor device HB is provided, which is to be attached to the surface OF of the metal substrate MT. The semiconductor device HB can be a bare chip, specifically one that is directly separated from a wafer. If the assembly VB is to form part of a power module of a power inverter, the semiconductor device HB can be a Si, SiC, or GaN semiconductor device.
[0049] Subsequently, according to step S300, the height H1 (or thickness) of the semiconductor device HB is measured, and based on this measured height H1, a height H2 required to protect the semiconductor device HB from external mechanical influences, such as vertical pressure loads, is determined according to a further step S400. The required height H2 is set such that it is slightly greater than the measured height H1 of the semiconductor device HB, for example, by a maximum of approximately 10%.
[0050] According to step S500, a protective element SE is provided to protect the semiconductor device HB, which has the determined required height H2 (or thickness). Depending on the embodiment, step S500 comprises the following substeps, some of which may occur before or during the previously described steps S100, S200, S300, and S400: In order to provide a protective element SE with a required height H2 that is still unknown before step S400 (determining the required height H2 of the protective element SE), a maximum possible height Hx1 of the semiconductor component HB, i.e., an expected maximum height of the semiconductor component HB, is predicted in advance, especially well before step S400, according to substep S510. This maximum possible height Hx1 can be predicted or determined based on possible target heights of semiconductor components of different designs, types, and manufacturers, and taking into account possible permissible manufacturing tolerances.
[0051] Similarly, other maximum possible dimensions, such as maximum possible length and width, of the semiconductor component HB are predicted or determined based on corresponding target dimensions of semiconductor components of different designs, types and manufacturers, and taking into account possible permissible manufacturing tolerances.
[0052] Based on this maximum possible height of the semiconductor device HB, a maximum required height Hx2 of the protective element is determined according to a further substep S520. The maximum required height Hx2 of the protective element is set such that it is slightly greater than the respective maximum possible height Hx1, e.g., by a maximum of approximately 10%.
[0053] Furthermore, based on the previously determined maximum possible dimensions of the semiconductor device, the minimum required dimensions of the protective element, such as its minimum required length and width, are defined. First, the desired shape of the protective element, such as a square ring, is determined. Then, based on the previously determined maximum possible dimensions of the semiconductor device, the minimum required dimensions of the protective element are defined, including its minimum required length and width, as well as the minimum required area of the surface that will enclose the protective element and in which the semiconductor device will be placed.
[0054] Once the maximum required height Hx2 of the protective element has been determined, a large number of protective element blanks are pre-formed in the predetermined square ring shape, in the expected maximum required height Hx2, and in the previously determined minimum required other dimensions, according to a further sub-step S530. These blanks are, for example, punched, cut, or formed in a comparable separation process from a copper sheet that has the maximum required height Hx2 (as a uniform sheet thickness) in the corresponding square ring shape.
[0055] Depending on the production plan, the above-mentioned sub-steps S510, S520 and S530 can be carried out before or during the previously mentioned steps S100, S200, S300 and S400.
[0056] Once the required height H2 of the protective element has been determined according to step S400, one of the protective element blanks preformed according to substep S530 is taken and embossed according to a subsequent substep S540, so that it is pressed down to the required height H2 determined according to step S400.
[0057] Subsequently, the semiconductor device HB and the protective element SE are positioned and attached to the surface OF of the metal substrate MT in a further step S600. To optimally protect the semiconductor device HB from external mechanical influences, the square-ring-shaped protective element SE is placed around the perimeter of the semiconductor device HB.
[0058] In this process, the two elements HB and SE can be applied to the surface OF of the metal carrier MT and sintered onto the surface OF in the same manufacturing step, namely in the same sintering process.
[0059] Alternatively, the two elements HB and SE can be applied sequentially in two manufacturing steps and / or attached to the surface OF using different joining techniques. For example, the semiconductor component HB can be sintered onto the surface OF in a sintering process, and the protective element SE can be soldered onto the surface OF in a soldering process.
[0060] As an alternative to the previously described substeps S530 and S540, where a large number of protective element blanks are preformed to the same expected maximum required height Hx2, and one of these is taken and embossed to the required height H2 determined according to step S400, a large number of protective elements in different heights, whose range extends up to the maximum required height Hx2 of the protective element determined according to substep S520, can be preproduced according to substep S550. For this purpose, the protective elements can be preproduced by punching, cutting, or separating them from a large number of semi-finished products, in particular from a large number of copper sheets, in different heights, whose range extends up to the maximum required height Hx2.
[0061] Optionally, according to substep S510, in addition to the maximum possible height Hx1, a minimum possible height Hs1 of the semiconductor device can also be predicted, i.e., an expected maximum and minimum height of the semiconductor device, whereby these two heights Hx1 and Hs1 are predicted or determined based on possible target heights of semiconductor devices of different designs, types and manufacturers, and taking into account possible permissible manufacturing tolerances.
[0062] Based on this maximum possible height Hx1 or the minimum possible height Hs1 of the semiconductor device, a minimum required height Hs2 of the protective element is determined in accordance with substep S520, in addition to the maximum required height Hx2, whereby the maximum required height Hx2 and the minimum required height Hs2 of the protective element are determined such that they are each slightly, e.g. by a maximum of approximately 10% of the respective minimum or maximum possible height Hs1, Hx1 of the semiconductor device.
[0063] According to substep S550, the protective elements are then pre-produced in different heights, the range of which extends from the previously defined minimum required height Hs2 to the maximum required height Hx2 of the protective element.
[0064] According to the subsequent sub-step S560, a protective element SE is then selected from the multitude of protective elements pre-produced according to sub-step S550, which has the determined required height H2.
[0065] The semiconductor component HB and the protective element SE are then positioned and attached to the surface OF of the metal carrier MT as described previously in step S600.
Claims
[1] Method for producing a metal carrier-semiconductor assembly (MC) comprising: - a metal carrier (MT) with a surface (OF); - a semiconductor device (HB) that is arranged on the surface (OF) of the metal substrate (MT); - at least one protective element (SE) arranged on the surface (OF) of the metal substrate (MT) and forming at least a partial circumferential shape around the semiconductor device (HB); - wherein the protective element (SE) has a height (H2) that is equal to or greater than the height (H1) of the semiconductor device (HB), by the following process steps: - Providing (S100) a metal carrier (MT) with a surface (OF); - Provision (S200) of a semiconductor device (HB); - Measuring (S300) the height (H1) of the semiconductor device (HB); - Determining (S400) a required height (H2) of a protective element (SE) based on the measured height (H1) of the semiconductor device (HB), wherein the required height (H2) is equal to or greater than the height (H1) of the semiconductor device (HB); - Providing (S500) a protective element (SE) that has the determined required height (H2); - Arranging (S600) the semiconductor device (HB) and the protective element (SE) on the surface (OF) of the metal substrate (MT), wherein the protective element (SE) is arranged at least partially around the semiconductor device (HB). [2] Method according to claim 1, wherein the step of providing (S500) the protective element (SE) further comprises the following substeps: - Predicting (S510) a maximum possible height (Hx1) of the semiconductor device (HB); - Determining (S520) a maximum required height (Hx2) of the protective element (SE) based on the predicted maximum possible height (Hx1) of the semiconductor device (HB). [3] Method according to claim 1 or 2, wherein the step of providing (S500) the protective element (SE) comprises the following substeps: - Pre-production (S550) of a large number of protective elements in different heights, the value range of which extends in particular to the maximum required height (Hx2) of the protective element (SE); - Selecting (S560) the protective element (SE) from the multitude of pre-produced protective elements that has the determined required height (H2). [4] Method according to claim 3, wherein the pre-production (S550) of the plurality of protective elements in different heights will be carried out by punching or cutting out or separating protective elements (SE) from a plurality of semi-finished products, in particular from a plurality of sheets, in different heights. [5] Method according to claim 2, wherein the step of providing (S500) the protective element (SE) further comprises the following substeps: - Preforms (S530) of a protective element blank in the maximum required height (Hx2), in particular by punching or cutting out or separating the protective element blank from a semi-finished product, in particular from a sheet that has the expected maximum required height (Hx2); - Embossing (S540) the preformed protective element blank to form the protective element (SE) at the determined required height (H2). [6] Method according to any one of claims 1 to 5, wherein the step of arranging (S600) the semiconductor device (HB) and the selected protective element (SE) onto the surface (OF) of the metal substrate (MT) further provides that the semiconductor device (HB) and the protective element (SE) are attached to the surface (OF) of the metal substrate (MT) in the same joining process and / or with the same joining technique, in particular sintered or soldered onto the surface (OF) of the metal substrate (MT) in the same sintering or soldering process. [7] Method according to claim 1, wherein the protective element (SE) and the semiconductor device (HB) are sintered or soldered onto the surface (OF) of the metal carrier (MT). [8] Method according to claim 1 or 2, wherein the protective element (SE) and the metal carrier (MT) are formed from the same material, in particular copper or a copper alloy. [9] Method according to any one of claims 1 to 3, wherein the protective element (SE) is formed in a U-shape or C-shape or ring-shaped or polygonal ring-shaped, in particular in a quadrilateral ring-shaped. [10] Method according to any one of claims 1 to 4, wherein the protective element (SE) is formed in an I-shape, wherein the assembly (VB) has at least two protective elements (SE) which are distributed on two opposite sides of the semiconductor device (HB).