Power Module Having Reduced Susceptibility to Defects, and Use Thereof

Abstract

A power module is disclosed. In an embodiment a power module includes a carrier substrate having a dielectric layer, a metallization layer and a recess and an electrical functional element, wherein the metallization layer includes a structured electrical conductor, wherein the functional element is interconnected with the electrical conductor, wherein the functional element is arranged in the recess, and wherein the functional element includes a thermal bridge that has a greater thermal conductivity than the carrier substrate.

Claims

1-18. (canceled)

19. A power module comprising: a carrier substrate having a dielectric layer, a metallization layer and a recess; and an electrical functional element, wherein the metallization layer comprises a structured electrical conductor, wherein the functional element is interconnected with the electrical conductor, wherein the functional element is arranged in the recess, and wherein the functional element comprises a thermal bridge that has a greater thermal conductivity than the carrier substrate.

20. The power module according to claim 19, wherein the thermal bridge is configured to remove heat, generated during operation, to an underside of the power module.

21. The power module according to claim 19, wherein the thermal bridge comprises a ceramic material.

22. The power module according to claim 19, wherein the thermal bridge comprises a material selected from the group consisting of ZnOBi, ZnOPr, AlN, Al.sub.2O.sub.3, and SiC.

23. The power module according to claim 19, wherein the thermal bridge comprises a multilayer structure having a dielectric layer and a metallization layer.

24. The power module according to claim 19, wherein the thermal bridge comprises an ESD protective element.

25. The power module according to claim 19, wherein the thermal bridge comprises a varistor.

26. The power module according to claim 19, wherein the functional element comprises functional structures configured to emit light.

27. The power module according to claim 19, wherein the carrier substrate and/or the functional element have/has vertical through-platings.

28. The power module according to claim 19, wherein an electrical connection between the electrical conductor and the functional element is compensated with respect to a thermal expansion.

29. The power module according to claim 28, wherein electrically conducting structures on an underside of the functional element and on an upper side of the recess comprise the same material.

30. The power module according to claim 19, further comprising a gap filled with a temperature buffer that has the same temperature expansion coefficient as the gap.

31. The power module according to claim 19, further comprising a driver circuit arranged on or in the carrier substrate, or on or in the functional element, wherein the driver circuit is configured to drive the functional element.

32. The power module according to claim 19, further comprising a sensor arranged on or in the carrier substrate, or on or in the functional element.

33. The power module according to claim 19, wherein the power module comprises a plurality of functional elements which are positioned in a regular arrangement in the recess.

34. The power module according to claim 19, wherein the power module is an LED matrix module.

35. The power module according to claim 19, wherein the dielectric layer comprises a ceramic material or is composed of a ceramic material, or comprises an organic material or is composed of an organic material, or comprises glass or is composed of glass.

36. A vehicle comprising: a lamp comprising the power module according to claim 19.

37. A power module comprising: a carrier substrate having a dielectric layer, a metallization layer and a recess; and an electrical functional element, wherein the metallization layer comprises a structured electrical conductor, wherein the functional element is interconnected with the electrical conductor, wherein the functional element is arranged in the recess, wherein the functional element comprises a thermal bridge, which has a greater thermal conductivity than the carrier substrate, wherein the thermal bridge comprises or a material selected from the group consisting of ZnOBi, ZnOPr, AlN, Al.sub.2O.sub.3, and SiC, and wherein the thermal bridge comprises an ESD protective element and/or a varistor.

38. A power module comprising: a carrier substrate having a dielectric layer, a metallization layer and a recess; an electrical functional element; a driver circuit configured to drive the functional element, wherein the driver circuit is arranged on or in the carrier substrate, or on or in the functional element; and a sensor arranged on or in the carrier substrate, or on or in the functional element, wherein the metallization layer comprises a structured electrical conductor, wherein the functional element is interconnected with the electrical conductor, wherein the functional element is arranged in the recess, and wherein the functional element comprises a thermal bridge, the thermal bridge having a greater thermal conductivity than the carrier substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Functioning principles of the power module and selected details of possible embodiments are explained in greater detail in the following, on the basis of the schematic figures.

[0055] There are shown

[0056] FIG. 1 shows the position of a functional element in a recess in the carrier substrate;

[0057] FIG. 2 shows a functional element comprising a functional structure and a thermal bridge;

[0058] FIG. 3 shows an embodiment of the thermal bridge having a multilayer structure;

[0059] FIG. 4 shows the arrangement of the functional element in a recess that extends fully through the carrier substrate;

[0060] FIG. 5 shows a top view of a matrix arrangement of functional elements;

[0061] FIG. 6 shows an arrangement of a plurality of functional elements in a single recess;

[0062] FIG. 7 shows a functional element having a plurality of functional structures, arranged next to each other, and an ESD protection in the thermal bridge;

[0063] FIG. 8 shows a power module comprising a sensor; and

[0064] FIG. 9 shows a power module comprising a driver circuit.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0065] FIG. 1 shows the basic structure of a power module LM, having a carrier substrate TS that comprises a plurality of layers. These include, in particular, dielectric layers DL of an insulating material, and metallization layers ML, in which electrical structures can be formed. In the carrier substrate TS there is a recess AN, in which the functional element FE is arranged. The recess shown in FIG. 1 has the shape of a so-called blind hole, i.e., the recess has a base. The functional element FE sits on the base of the recess. In the case of a power module LM having a recess AN that is open only in one direction, the side toward which the recess AN is open is the upper side OS. The opposite side is the underside US.

[0066] The functional element FE is interconnected, via an electrical contact EK, with the electrical conductor EL, e.g., formed in a metallization layer.

[0067] Heat that is formed in the functional element FE, in particular on the upper side of the functional element FE, penetrates the functional element FE with little resistance. In order that this heat can be removed, via the underside US of the power module LM, to an external environment, in the case of a blind hole, as a recess AN, a lesser quantity of carrier substrate material has to be overcome than if the functional element FE were arranged, not in a recess, but on the upper side OS of the carrier substrate.

[0068] Correspondingly, it is also preferred if the local thickness of the carrier substrate TS in the region of the recess AN is less than locally in a region without a recess.

[0069] FIG. 2 shows an arrangement in which the functional element FE has two regions, arranged one above the other. The upper region is formed by a portion having functional structures FS, which realize, for example, an electrical or electronic or optical function. Arranged beneath it is the thermal bridge WB, which conducts heat, generated in the upper portion, to the underside of the functional element FE, and thus to the underside of the power module.

[0070] In order to simplify transfer of the heat to the underside of the power module, the thermal bridge WB is connected to the base of the recess via a thermal coupling TA. The thermal coupling TA, e.g., formed by conductive paste or a metallization, reduces the thermal resistance. The thermal coupling TA in this case preferably comprises materials having low thermal resistance, e.g., copper or silver.

[0071] Terminal connection pads AP, which are formed, for example, by a UBM (UBM=under-bump metallization), may be provided on the underside of the power module. Via such a terminal connection pad, the power module can be connected to, and interconnected with, an external environment.

[0072] FIG. 3 shows details of a power module in which the thermal bridge WB has a multilayer structure. Arranged therein, above one another, are dielectric layers and metallization layers. Such a structure conducts heat well if the material if the dielectric material is selected accordingly. In addition to removing heat, such a thermal bridge WB may provide an electrical or electrical function. It is thus possible for electrodes to be formed in the metallization layers. The electrodes are separated from each other in the vertical direction by dielectric material. Differing terminal connections are assigned to electrodes that are adjacent in the vertical direction. If the dielectric material is a varistor ceramic, the two differing terminal connections are insulated from each other with respect to a low voltage. If a high voltage, e.g., an ESD pulse is present at the two differing terminal connections, the varistor ceramic exhibits a reduced electrical resistance and the ESD pulse can be diverted to a reference potential.

[0073] The thermal bridge WB has vertical through-platings DK (vias), via which the functional structures FS on the upper side of the functional element are interconnected with structured metallizations of the carrier substrate.

[0074] In the multilayer carrier substrate, also, there are through-platings DK, which interconnect the circuit elements or conductors of differing metallizations layers. Through-platings DK make it possible for all external terminal connections of the power module to be arranged on one side of the power module, facilitating integration into an external circuit environment.

[0075] The multilayer structure of the functional element FE has an additional external wiring UV, in order to simplify the electrical contacting of the functional structures to terminal contacts on the thermal bridge WB.

[0076] In the horizontal direction, the functional element FE is spaced apart from the lateral walls of the recess. This volume is filled by material of a temperature buffer TP, which has a temperature expansion coefficient selected such that the increase and decrease of the buffer TP is equal to the increase and decrease of the width of the gap.

[0077] FIG. 4 shows a form of a power module in which the recess extends fully through the carrier substrate, and in the entire region of the base. In order to reduce maximally the overall height of the power module, the functional element is fully embedded in the carrier substrate. In order to simplify integration into an external environment, and in particular to simplify the downward emission of heat, the underside of the functional element FE, in particular of its thermal bridge WB, and the underside US of the carrier substrate are in flush alignment, such that a substantially smooth underside of the power module as a whole is obtained.

[0078] Electrical contacts on the underside of the functional element may then project out of the underside of the power module. Alternatively, it is also possible for the functional element FE to be embedded in the carrier substrate only to such an extent that the underside of the carrier substrate is flush with the underside of the electrical contacts EK.

[0079] FIG. 5 shows a top view of a matrix arrangement MA, in which a multiplicity of functional elements FE is aligned in rows and columns.

[0080] FIG. 6 illustrates the possibility of providing a single recess, and arranging a multiplicity of functional elements FE therein. Each of the functional elements FE may comprise a thermal bridge having a multilayer structure, and functional structures above the thermal bridge.

[0081] The uppermost layer of the carrier substrate may be a mirror SP that reflects light. If the functional structures constitute light sources, the total quantity of radiated light of the power module is increased if less light is absorbed by the otherwise passive upper side of the carrier substrate.

[0082] FIG. 7 shows the possibility of providing a plurality of functional structures FS in a single functional element FE. The thermal bridge of the functional element FE has a multilayer structure comprising varistor material, and provides an ESD protective function.

[0083] FIG. 8 shows the possibility of arranging a sensor directly on the upper side of the functional element FE. Alternatively, the sensor may also be arranged in the multilayer structure of the functional element or in the carrier substrate.

[0084] FIG. 9 thus shows the possibility of arranging the sensor S inside the multilayer structure of the carrier substrate. Arranged on the functional element FE, on the other hand, is a driver circuit TSG for driving the functional structures and controlling their mode of operation by open-loop or closed-loop control. The driver circuit TSG in this case may also include electrical or electronic power components. In this case, arrangement on the thermal bridge is preferred.

[0085] The power module and the use of the power module are not limited by the technical features described and the details shown. Power modules having additional circuit elements, additional terminal connections and additional recesses are also included within the scope of protection.