DE102014201306A1 - Power electronics module with 3D-made cooler - Google Patents

Abstract

A first aspect of the invention introduces a manufacturing method for a power electronics module (1). The method according to the invention has at least the following steps: provision of a power electronic component (8); and - applying a cooling structure (9) directly to the power electronic component (8) by means of a three-dimensional layer-by-layer application method. A second aspect of the invention relates to the power electronics module (1) produced or producible by the method according to the invention.

Description

Technical area

The invention relates to a production method for a power electronics module and to a power electronics module produced or producible with this production method.

Technical background

Power electronics components are used for a variety of applications, for example, to switch strong electrical currents within a short time, as is common in inverters. Such power electronic components may comprise a plurality of switching transistors such as IGBTs (Insulated Gate Bipolar Transistor), which are arranged on a flat substrate next to each other to a power electronics circuit. For this purpose, for example, the DBC or DCB technique (Direct Bonded Copper) widely used in which a ceramic substrate provided on both sides with structured copper layers and arranged the switching transistors on one of the structured copper layers and thereby connected to a power electronics circuit.

Due to the high flowing currents and loads to be switched, this generates waste heat, which must be dissipated to protect the power electronics circuit from overheating. For this purpose, the power electronic component is combined with a cooler to form a power electronics module. In the case of the DCB technology, the remaining structured copper layer is also used for the dissipation and distribution of the pointwise different amounts of waste heat and for the control of the resulting due to the unevenly distributed heat dissipation mechanical stresses and structured suitable for this purpose.

The one or more coolers of a power electronics module can be arranged on any side of a DCB substrate. These coolers can be designed as a microchannel cooler, which absorb the waste heat of the power electronics circuit and deliver to a liquid coolant flowing through the microchannel cooler.

By the cooling measures the highest possible packing density of the power electronics modules and thus the largest possible switchable electrical power is achieved in a given volume, without having to fear overheating of the power electronics modules.

The invention has for its object to introduce an improved manufacturing method for power electronics modules and improved power electronics modules.

Summary of the invention

• – Bereitstellen eines Leistungselektronikbauteils; und
• – Auftragen einer Kühlstruktur direkt auf das Leistungselektronikbauteil mittels eines dreidimensionalen schichtweisen Auftragsverfahrens.

A first aspect of the invention therefore introduces a manufacturing method for a power electronics module. The method according to the invention has at least the following steps:

• - Providing a power electronics component; and
• - Applying a cooling structure directly to the power electronics component by means of a three-dimensional layered application method.

The method of the invention offers a number of advantages. Thus, by using a three-dimensional layer-by-layer application method, as it is known from rapid prototyping or so-called 3D printing, it is possible to construct complex cooling structures that could not be realized in the classical design of a microchannel cooler. This is advantageous because the diameter, ramifications and positioning of coolant channels in the cooling structure and also turbulence of the coolant in the coolant channels can be optimized in terms of flow, so that the best possible distribution of the coolant along the surface to be cooled according to the conditional by the spatial arrangement of the power electronics circuit Conditions of the waste heat distribution can take place. The coolant channels of the cooling structure can be calculated and optimized using methods of CFD (computational fluid dynamics).

Another advantage of the invention is its rapid implementation that shortens production time. In addition, a particularly good heat-conducting contact between the cooling structure and the power electronics component can be produced by the cooling structure is constructed directly on the power electronics component and thereby connected to the power electronics component. In contrast, the known cooler with thermal paste or the like are applied to the power electronics components. However, this results in a relatively poor thermal conductivity of about 3 to 10 W / mK.

Particularly preferred for the three-dimensional layer-by-layer application method, a powder application method is used. In preferred examples of such powder application methods, thin powder layers of a material to be selected, usually metallic material or plastic, are applied to the power electronic component serving as substrate for the application process and then selectively hardened by an energy beam, for example a laser or electron beam. By doing Each layer is hardened selectively selectively, arises from the plurality of layers, finally, the desired shape of the cooling structure. Finally, the powder is removed from the non-hardened areas.

However, liquid-based application methods are also applicable, for example galvanic methods using photolithographic patterning methods.

In the three-dimensional layered application method for the construction of the cooling structure, at least one plastic layer or a plastic sublayer can be applied. Such a plastic layer can be used in particular in conjunction with a plurality of metallic layers or partial layers in order to electrically isolate the cooling structure from the power electronic component. In addition, any coolant channels contained in the cooling structure can be coated in this way with plastic, which can serve the corrosion protection. This is particularly advantageous in a structure of the cooling structure made of copper and / or a use of water as a coolant or water-containing coolants. However, the coating of the coolant channels with plastic can also be achieved by other methods. It is also conceivable to carry out the coolant channels made of aluminum or another corrosion-resistant metallic material.

In advantageous embodiments of the method according to the invention, a plurality of different materials can be applied in a selected layer in the three-dimensional layered application method. This can be used, for example, for the above-described construction of corrosion-resistant coolant channels within a cooling structure of corrosion-prone material. However, it is also conceivable to provide a cooling structure made of a selected material (for example with particularly good heat conduction properties) with a housing (for example made of stainless steel) for protection thereof, by using and structuring the different materials for different areas of each selected layer.

Particularly preferably, in the step of applying the cooling structure, at least one coolant channel is formed in the cooling structure. The at least one coolant channel may be provided with connections for the coolant. If appropriate, such connections can be realized directly by the three-dimensional layer-by-layer application method, for example using a plastic material.

The step of providing the power electronic component may include a step in which a power semiconductor chip of the power electronic component is contacted by a planar interconnect method. Here, in particular, the so-called SiPLIT method (Siemens PLanar Interconnect Technology), as for example in WO03 / 030247 A2 is described, suitable. This method has the advantage that the switching transistors (or other active elements such as diodes, etc.) of the power electronics circuit are contacted directly and flatly, resulting in a substantially planar surface of the power electronics component, to which the cooling structure can be applied in the context of the inventive method , However, the cooling structure can also (or additionally) on the back of the substrate, so the power electronics circuit opposite, are applied. This has the advantage of a flat substrate surface on which the cooling structure can be easily constructed, but brings with the use of substrates with a ceramic layer such as DCB substrates or aluminum substrates the disadvantage of caused by the ceramic layer thermal barrier.

A further advantage of the combination of a planar interconnect method such as SiPLIT and the method according to the invention is that the cooling structure can be arranged at a particularly small distance from the switching transistors. In power electronics circuits that are contacted with the traditional short-wire bonding, these wires are usually mechanically stabilized by casting a relatively thick, usually silicone-containing, resin layer, which represents a significant thermal barrier, which makes cooling up significantly more difficult. In contrast, when using a planar interconnect method, a relatively thin insulating layer can be applied to the power electronics component, for example in the form of a laminated film, as used in the SiPLIT process, on which the cooling structure is then built up directly. This insulation layer can also be generated in the context of the three-dimensional layer-wise application method itself, as explained above.

After the step of applying the cooling structure, a lid may be mounted on the cooling structure. This can be done for example by laser welding or appropriate methods. The cover may serve to complete and thereby protect the cooling structure. In addition, it may serve to fluidly seal open coolant channels, although holes may be provided in the cover for coolant supply and discharge lines. But it is also possible to attach a second power electronics module on the first. Here, both power electronics modules can be aligned spatially the same, so that the back one is attached to the front of the other, allowing stacks of multiple power electronics modules. Such stacks enable a particularly high packing density.

Alternatively, the two power electronics modules can point away from each other, so that the cooling structures of the two power electronics modules are arranged on top of each other. It is conceivable to connect the cooling structures of the two power electronic modules functionally and spatially, so that a coolant exchange between the power electronics modules is possible. For example, each of the power electronics modules may include an upper and a lower half of a single coolant channel, which is completed by the attachment of the two power electronics modules to each other. It is also conceivable that each cooling structure serves as a seal of the coolant channels of the respective other cooling structure.

A second aspect of the invention relates to the power electronics module produced or producible by the method according to the invention. Such a power electronics module can be differentiated, for example, from conventional ones based on the crystal structure of the cooling structure, the shaping of coolant channels or the absence of thermal compounds or adhesives between the power electronics component and the cooling structure.

Brief description of the pictures

The invention will be explained in more detail with reference to illustrations of exemplary embodiments. Show it:

1 a cross-sectional drawing through an embodiment of a power electronics module according to the invention;

2 a second embodiment of the invention; and

3 a third embodiment of the invention.

Detailed description of the pictures

1 shows a cross-sectional drawing through an embodiment of a power electronics module according to the invention 1 , The power electronics module 1 includes a power electronics component 8th and a cooling structure 9 directly on the power electronics component 8th has been applied by a three-dimensional layered application method.

In the exemplary embodiment shown, the power electronic component is 8th manufactured as a SiPLIT power electronic component, as in WO 03/030247 A2 in the 1 and 2 and the description on page 9, line 30, to page 13, line 20, which are incorporated by reference into this specification. The power electronics component 8th However, it can also be produced in other production techniques.

The SiPLIT power electronics component 8th comprises a substrate, which in the present case as a DBC substrate, a planar ceramic substrate 2 that has copper metallizations on both sides 3 and 4 is provided. The copper metallization 4 has been structured to build a power electronic circuit. The opposite copper metallization 3 can also be structured, but usually serves the distribution and dissipation of the waste heat of the power electronics component 8th , On the textured copper metallization 4 are semiconductor chips 5 applied to the copper metallization 4 contact surface. Such semiconductor chips 5 For example, they can be IGBTs widely used for switching large loads. The respective free surface locations of the ceramic carrier 2 , the copper metallization 4 and the semiconductor chips 5 are prepared according to the SiPLIT method with an insulator film 6 covered, which is structured at the desired locations, for example by laser, to make electrical connections of the power electronic circuit for the subsequent planar metallization accessible. With the surface metallization, which can be done for example in a combination of galvanic and photolithographic steps, contacts and connections 7 created through which the semiconductor chips 5 be connected to the desired power electronic circuit.

According to the invention directly to the power electronics component 8th using a three-dimensional layered application method, a cooling structure 9 built up. In the example of 1 becomes the cooling structure 9 applied to the power electronic circuit opposite side of the DCB substrate. But it is also possible, the cooling structure 9 on the other or on both sides of the substrate. For this purpose, for example, an additional layer on the power electronics component 8th be applied, which provides a flat surface as possible for the application of the cooling structure.

In the embodiment shown has the cooling structure 9 a main body formed of, for example, copper 10 in which a coolant channel 11 is arranged. The main body 10 is on its sides by a framing 16 , for example, made of stainless steel, edged and so on mechanically and chemically protected. The main body 10 preferably at the same time as the framing 16 applied in layers, which can be done for example in a powder application process in which a corresponding powder dispenser is available for each of the materials used. For each layer, the corresponding powders are applied at the desired locations and the resulting powder layer is structured with an energy beam such as a laser, for example selectively melted.

The coolant channel 11 has a supply line 12 and a derivative 13 , which are shown by way of example only. The invention has the advantage of a particularly simple production of cooling structures 9 with complex geometry of the coolant channels 11 , so that cooling structures 9 are possible, the a plurality of coolant channels 9 with branches, varying diameters and a greater number of connections for the coolant.

In the embodiment shown, the coolant channel 11 advantageous with a plastic layer 14 lined, which may also have been applied by the three-dimensional layered application method. But it is also possible, the coolant channel 11 with such a plastic layer 14 provided by the coolant channel 11 after the completion of the main body 10 rinsed with a plastic solution or the like, and from the plastic solution a plastic layer 14 is deposited. Becomes the main body 10 the cooling structure, however, made of aluminum or other corrosion-resistant material, such a plastic layer 14 also omitted. It is also possible, the coolant channel 11 made of a corrosion-resistant material, such as aluminum. The exact choice of materials may depend on the compatibility of the different metals etc. of the cooling structure 9 , the metallization of the power electronics component 8th and in particular the metallization 3 of the substrate to be taken among each other by a person skilled in the art.

At the in 1 the embodiment shown is the cooling structure 9 with a lid 15 provided, which may be made of stainless steel, for example. The lid 15 can be fixed with a laser welding method or the like and holes for the terminals 12 . 13 of the coolant channel 11 exhibit. Of course it is also possible the connections 12 . 13 laterally from the cooling structure 9 lead out. Instead of a lid 15 For example, layers of a durable material such as stainless steel can be applied to complete the three-dimensional layered application process, which then acts as a lid.

2 shows a second embodiment of the invention. Here were two power electronics modules according to the invention 1 combined together by the respective cooling structures 9 were arranged on top of each other. The cooling structures 9 For example, they can be welded together. This structure allows a particularly space-favorable arrangement. To a larger number of power electronics modules 1 can combine several such pairs of power electronics modules 1 be arranged on top of each other.

In advantageous embodiments of the invention, by attaching the cooling structures 9 one coolant channel or a plurality of coolant channels are fluidically sealed to the corresponding ports. That is, during the three-dimensional layer-by-layer deposition process, exposed coolant channels are formed, correspondingly mirror-inverted in both power electronics modules 1 are present and when fixing the two cooling structures 9 form mutually complete coolant channels.

3 shows a third embodiment of the invention, in which two power electronics modules according to the invention 1 have been arranged on each other by the cooling structure 9 of a power electronics module 1 on the power electronics component 8th of the other power electronics module 1 is fastened. This creates a stacked structure, in which more than two power electronics modules 1 can be combined.

Although the invention has been illustrated and described in detail by preferred embodiments, the invention is not limited by the disclosed examples. Variations may be derived by those skilled in the art without departing from the scope of the invention as defined in the appended claims.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 03/030247 A2 [0015, 0025]

Claims (10)

A method of manufacturing a power electronics module ( 1 ) and with the steps: - Provision of a power electronics component ( 8th ); and - applying a cooling structure ( 9 ) directly on the power electronics component ( 8th ) by means of a three-dimensional layer-by-layer application method.  The method of the preceding claim, wherein the three-dimensional layer coating method is a powder coating method. The method of one of the preceding claims, wherein in the three-dimensional layered application method for the construction of the cooling structure ( 9 ) a plurality of metallic layers are applied. The method of one of the preceding claims, wherein in the three-dimensional layered application method for the construction of the cooling structure ( 9 ) at least one plastic layer ( 14 ) or a plastic sublayer is applied.  The method of any one of the preceding claims, wherein in the three-dimensional layered application process, a plurality of different materials are applied in a selected layer. The method of any one of the preceding claims, wherein in the step of applying the cooling structure ( 9 ) at least one coolant channel ( 11 ) in the cooling structure ( 9 ) is formed. The method of the preceding claim, wherein the at least one coolant channel ( 11 ) in the step of applying the cooling structure ( 9 ) is formed from a metal, in particular aluminum or copper, or from a plastic. The method of one of the preceding claims, wherein the step of providing the power electronics component ( 8th ) comprises a step in which a power semiconductor chip ( 5 ) of the power electronic component ( 8th ) is contacted by a planar interconnect method. The method of any one of the preceding claims, wherein after the step of applying the cooling structure ( 9 ) a lid ( 15 ) on the cooling structure ( 9 ) is attached. A power electronics module manufactured or producible by the method of any of the preceding claims ( 1 ).

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