Multi-chip module and method for producing a multi-chip module

Abstract

The invention relates to a multi-chip module and to a method for producing same, said multi-chip module having a first chip (10), a second chip (20) and an isolation chip (30). The first chip (10) is designed to be used in a first voltage domain, and the second chip (20) is designed to be used in a second voltage domain which has a potential difference with respect to the first voltage domain. The isolation chip (30) has at least one galvanically isolating coupling element (40), and the isolation chip (30) is designed to facilitate a signal transmission and / or a power transmission between at least one first terminal (32) and at least one second terminal (34) of the isolation chip (30) via the galvanically isolating coupling element (40). The first chip (10) and the second chip (20) are located next to each other with a specified spacing, and the isolation chip (30) is mounted directly on the first chip (10) and the second chip (20) on the basis of a flip-chip mounting process such that at least one module-internal terminal (12) of the first chip (10) is permanently connected to the first terminal (32) of the isolation chip (30) and such that at least one module-internal terminal (22) of the second chip (20) is permanently connected to the second terminal (34) of the isolation chip (30).

Description

[0001] Description

[0002] title

[0003] Multi-chip module and method for manufacturing a multi-chip module

[0004] State of the art

[0005] The present invention relates to a multi-chip module and a method for manufacturing such a multi-chip module.

[0006] Isolated gate drivers for controlling power semiconductors such as IGBTs and / or MOSFETs are known from the prior art, which are used, for example, in drive inverters of electrically operated vehicles and / or in devices differing from these.

[0007] This ensures electrical isolation between a control circuit and a gate driver for controlling a power semiconductor by means of a galvanically isolated coupling element, which is connected between the control circuit and the gate driver. In this way, the control circuit and the gate driver can be operated in different voltage domains, with the control circuit, for example, operating in a 5 V voltage domain and the gate driver in a 400 V voltage domain.

[0008] Galvanic isolation is achieved, for example, by means of one or more coupling capacitors and / or transformers, which enable signal transmission and / or power transmission from the control circuit to the gate driver.

[0009] Furthermore, it is known to design such control circuits, gate drivers and galvanically isolating coupling elements as separate chips, which can be integrated together into a multi-chip module (as a so-called "system-in-package") by typically arranging them next to each other and electrically connecting them to each other by means of bond wires.

[0010] Disclosure of the invention

[0011] According to a first aspect of the present invention, a multi-chip module is proposed comprising at least one first chip, one second chip, and one isolation chip, wherein the chips are each configured as separate components on separate substrates. The first chip and / or the second chip and / or the isolation chip can, for example, each be configured as an integrated circuit (e.g., as an ASIC) or, alternatively, be integrated as a so-called "system-in-package".

[0012] The first chip is set up to be used in a first voltage domain, while the second chip is set up to be used in a second voltage domain, which has a potential difference to the first voltage domain, so that the two voltage domains must be galvanically isolated from each other.

[0013] The isolation chip has at least one galvanically isolating coupling element and is configured to enable signal transmission (in particular data transmission) and / or power transmission between at least one first terminal and at least one second terminal of the isolation chip via the galvanically isolating coupling element. The terminals are designed, for example, as contact bumps in the form of so-called "bumps" or "balls," but are not limited to this.

[0014] Furthermore, it is advantageous for the isolation chip to have additional connections, for example, to close a single circuit and / or a multitude of circuits between the first and second chips via the isolation chip. Alternatively or additionally, it is also conceivable that the multi-chip module has a multitude of isolation chips, each with at least two connections, to enable signal transmissions between the first and second chips via several separate isolation chips.

[0015] It should be noted in general that the direction of signal transmission and / or power transmission between the first chip and the second chip is not fundamentally restricted.

[0016] The first and second chips are arranged side by side at a predefined distance, while the isolation chip is mounted directly onto the first and second chips using a flip-chip assembly. This ensures that at least one internal module connection of the first chip is permanently electrically connected to the first connection of the isolation chip, and at least one internal module connection of the second chip is permanently electrically connected to the second connection of the isolation chip. According to the prior art flip-chip assembly, the isolation chip is thus directly contacted with the respective internal module connections of the first and second chips without the need for separate bond wires. Such direct contacting is achieved, for example, using solder and / or an electrically conductive adhesive and / or a weld to connect the respective electrical contact points (i.e., the terminals)., connections) between the respective chips to connect electrically (and ideally also mechanically).

[0017] It is understood that electrical contact between the first chip and / or the second chip and the outside, i.e., outside the multi-chip module, is made via module connections, each of which is connected to external connections of the first chip and / or the second chip (e.g., by means of bond wires) and which may be designed, for example, as contact pads and / or pins and / or "bumps" and / or "balls", etc.

[0018] It should be noted that the functionality of the first and second chips is not fundamentally restricted, and that signal transmission between the first and second chips based on the isolation chip and / or on the basis of a plurality of isolation chips can represent a unidirectional or a bidirectional signal transmission. The multi-chip module according to the invention offers a multitude of advantages, which are briefly described below.

[0019] Firstly, it is possible to implement differential data transmission between the first chip and the second chip in a particularly robust manner, since the elimination of bond wires in the contacting of the respective chips with each other allows for particularly low undesired asymmetries in the routing between the chips.

[0020] Furthermore, bond wires, due to their length, typically act as antennas, which can cause problems related to electromagnetic interference (EMI). Flip-chip assembly, therefore, reduces potential EMI problems due to its particularly short electrical connection paths.

[0021] Furthermore, improved shielding of the galvanically isolating coupling element against interference can be achieved based on a substrate of the insulation chip rotated by the flip-chip assembly.

[0022] Furthermore, a so-called shear test, which is usually performed for bond wire-connected chips, can be omitted.

[0023] Finally, time savings and / or cost savings can be achieved by eliminating the bond wires used in the prior art.

[0024] Accordingly, the multi-chip module according to the invention can be used particularly advantageously in an electrically powered vehicle (e.g., in a drive inverter of the vehicle), since signal transmissions between a control domain and a power domain are generally required in such vehicles, and particularly high levels of interference are present, which can negatively affect signal transmission. This explicitly does not preclude the possibility that the multi-chip module according to the invention can be used advantageously in other fields of application, either alternatively or additionally.

[0025] The dependent claims describe preferred embodiments of the invention. In an advantageous embodiment of the present invention, the first chip is mounted on a first terminal frame and the second chip is mounted on a second terminal frame, wherein the first terminal frame and the second terminal frame are, for example, formed from a single terminal frame which is at least electrically separated during the manufacture of the multi-chip module according to the invention (for example, by cutting and / or punching electrically conductive connecting webs of the terminal frame). The terminal frame is, for example, a terminal frame made of copper. Furthermore, it is advantageous that the predefined distance between the first chip and the second chip is determined as a function of the potential difference between the first voltage domain and the second voltage domain.

[0026] In a further advantageous embodiment of the present invention, the first chip comprises a control circuit, while the second chip comprises a driver circuit. Furthermore, the multi-chip module is configured to transmit a control signal generated by the control circuit via the isolation chip to the driver circuit of the second chip for controlling the driver circuit. Based on the driver circuit, it is thus possible to control a semiconductor switch, in particular a power semiconductor switch, on the basis of which, for example, an inverter and in particular a drive inverter for a vehicle can be designed.

[0027] Preferably, the first voltage domain represents voltages up to 5 V, more preferably up to 10 V, and more preferably up to 20 V. Alternatively or additionally, the second voltage domain represents voltages from 200 V to 10 kV, more preferably from 300 V to 10 kV, and particularly preferably from 400 V to 10 kV, without thereby limiting the voltage ranges to the aforementioned values. In a case as described above, in which the first chip comprises a control circuit and the second chip a driver circuit, in particular for a drive inverter for a vehicle, the control circuit can, for example, be arranged in a 5 V voltage domain and the driver circuit in a 400 V voltage domain. In a preferred embodiment of the present invention, the galvanically isolating coupling element is at least one capacitor and / or at least one transformer and / or at least one optocoupler.

[0028] In a further preferred embodiment of the present invention, the isolation chip comprises a plurality of coupling elements. Accordingly, it is possible for the isolation chip to have a plurality of identical and / or a plurality of different galvanically isolating coupling elements, on the basis of which the isolation chip is configured to provide different coupling types and / or transmission channels between the first chip and the second chip.

[0029] Furthermore, the multi-chip module advantageously features a multitude of isolation chips, each configured to enable signal transmission and / or power transmission between the first and second chips. For example, data transmission between the first and second chips can be achieved using a first isolation chip of the multi-chip module, which incorporates a capacitor as a galvanically isolating coupling element, and power transmission can be achieved using a second isolation chip of the multi-chip module, which incorporates a transformer as a galvanically isolating coupling element, without thereby limiting a specific design of the multi-chip module with multiple isolation chips to this example.

[0030] In a further advantageous embodiment of the present invention, the multi-chip module comprises a housing (e.g., made of a potting compound) which jointly encapsulates the first chip, the second chip, and the insulation chip. For electrical contacting of the first chip and / or the second chip, the multi-chip module has externally accessible module terminals, which are, for example, based on the terminal frames described above.

[0031] Alternatively or additionally, the isolation chip is configured to be mechanically connected to the first chip via at least one first dummy bump and to the second chip via at least one second dummy bump, which are not intended for signal transmission between the first and second chips. The use of such dummy bumps allows for a particularly stable mechanical connection between the isolation chip and the first and / or second chip.

[0032] According to a second aspect of the present invention, a method for manufacturing a multi-chip module is proposed, the method comprising: a first step for arranging a first chip, which is configured to be inserted in a first voltage domain, and a second chip, which is configured to be inserted in a second voltage domain, at a predefined distance from each other (e.g., on a terminal frame), wherein the second voltage domain has a higher potential difference than the first voltage domain; a second step for arranging an isolation chip on the first chip and the second chip, wherein at least one first terminal of the isolation chip is aligned with a corresponding module-internal terminal of the first chip and wherein at least one second terminal of the isolation chip is aligned with a corresponding module-internal terminal of the second chip.wherein the isolation chip comprises at least one galvanically isolating coupling element, via which signal transmission between the first and second terminals of the isolation chip is enabled, and a third step for permanently electrically connecting the first terminal of the isolation chip to the module-internal terminal of the first chip and for permanently electrically connecting the second terminal of the isolation chip to the module-internal terminal of the second chip based on a flip-chip assembly. The third step can, for example, comprise reflow soldering to electrically connect the contacts of the isolation chip to the respective contacts of the first and second chips. The features, combinations of features, and the advantages arising therefrom correspond to those described in connection with the first-mentioned aspect of the invention, as can be seen.that, to avoid repetition, reference is made to the above statements.

[0033] Brief description of the drawings The following are exemplary embodiments of the invention described in detail with reference to the accompanying drawings. The drawing shows:

[0034] Figure 1 shows a schematic cross-sectional view of a first embodiment of a multi-chip module according to the invention; and

[0035] Figure 2 shows a schematic top view of a second embodiment of a multi-chip module according to the invention.

[0036] Embodiments of the invention

[0037] Figure 1 shows a schematic cross-sectional view of a first embodiment of a multi-chip module according to the invention.

[0038] The multi-chip module comprises a first chip 10, which is formed on a first substrate 11, and a second chip 20, which is formed separately from the first chip 10 on a second substrate 21. Depending on the different voltage domains in which the two chips 10 and 20 are arranged, the first chip 10 and the second chip 20 are positioned side by side on a first terminal frame 50 and a second terminal frame 52, respectively, at a predefined protective distance from each other, as described below.

[0039] Furthermore, the multi-chip module has an isolation chip 30, which is formed on a third substrate 31 and has a capacitor 40 as a galvanically isolating coupling element.

[0040] The aforementioned components of the multi-chip module are integrated together in a housing 80, which has at least one first module connection 82 and one second module connection 84, through which electrical contacting of the multi-chip module from the outside is made possible.

[0041] The first chip 10 is configured to be used in a first voltage domain, which here represents voltages up to 5 V, while the second chip 20 is configured to be used in a second voltage domain, which here represents voltages up to 400 V. The first chip 10 comprises a control circuit 60, which is configured to receive an input signal via a first external connection 14, which is connected to the first module connection 82 by means of a first bond wire 110, and to generate a control signal S for a driver circuit 70 based on an evaluation of the input signal, which is housed in the second chip 20.

[0042] The isolation chip 30 is configured to transmit the signal S generated by the control circuit 60 via the capacitor 40 between a first terminal 32 and a second terminal 34 of the isolation chip 30.

[0043] For this purpose, the isolation chip 30 is arranged on the first chip 10 and the second chip 20 during a flip-chip assembly process in the manufacture of the multi-chip module, rotated by 180° with respect to the first chip 10 and the second chip 20, by aligning the first connection 32 of the isolation chip 30 with a corresponding module-internal connection 12 of the first chip 10 and by aligning the second connection 34 of the isolation chip 30 with a corresponding module-internal connection 22 of the second chip 20.

[0044] The second chip 20 also has a second external connector 24, which is connected to the second module connector 84 by means of a second bond wire 120.

[0045] Subsequent reflow soldering melts solder balls provided at the terminals 32, 34 of the isolation chip 30 to create a metallurgical connection between the first terminal 32 of the isolation chip 30 and the module-internal terminal 12 of the first chip 10 and furthermore between the second terminal 34 of the isolation chip 30 and the module-internal terminal 22 of the second chip 20.

[0046] It should be noted that any other external and internal connections of the multi-chip module are not shown here for the sake of clarity. The multi-chip module described above is, for example, a multi-chip module designed for controlling power semiconductor switches in a drive inverter for a vehicle.

[0047] Figure 2 shows a schematic top view of a second embodiment of a multi-chip module according to the invention. Since the second embodiment shown in Figure 2 has numerous similarities to the first embodiment shown in Figure 1, only the differences between the two figures will be explained below to avoid repetition, and reference is otherwise made to the description of Figure 1.

[0048] The second embodiment of the multi-chip module according to the invention has an isolation chip 30 ' with a first capacitor 40 and a second capacitor 45, via which the multi-chip module is, for example, configured to realize a symmetrical transmission of a signal S from the first chip 10 to the second chip 20.

[0049] For this purpose, the first chip 10 is connected to a plurality of first module connections 82, via which, for example, an input signal SE and, for example, a supply voltage 90 are provided to the first chip 10. The first chip 10 is advantageously configured to generate the symmetrically formed control signal S as a function of the input signal SE.

[0050] Furthermore, a multitude of second module connections 84 are connected to the second chip 20, such that a gate driver 70 contained in the second chip 20, which is configured for controlling a (not shown) power semiconductor switch, is configured to generate a gate driver signal SA based on the control signal S, which is transmitted from the first chip 10 to the second chip 20 via the isolation chip 30, and to output this signal via the second module connections 84. Other available module connections 84 can be used, for example, for controlling another power semiconductor switch or for providing a supply voltage 100 for the second chip 20, or alternatively. It should be noted that instead of the isolation chip 30, which has the two capacitors 40, 45, two separate isolation chips 30 can be used, each having one of the capacitors 40, 45.

Claims

Claims 1. Featuring a multi-chip module: - a first chip (10), - a second chip (20), and - an isolation chip (30), wherein - the first chip (10) is set up, to be used in a first voltage domain, - the second chip (20) is set up to be used in a second voltage domain which has a potential difference to the first voltage domain, - the isolation chip (30) has at least one galvanically isolating coupling element (40) and the isolation chip (30) is configured to allow signal transmission and / or power transmission between at least one first terminal (32) and at least one second terminal (34) of the isolation chip (30) via the galvanically isolating coupling element (40), - the first chip (10) and the second chip (20) are arranged next to each other at a predefined distance, and - the isolation chip (30) is mounted directly on the first chip (10) and the second chip (20) on the basis of a flip-chip assembly, such that at least one module-internal connection (12) of the first chip (10) is permanently connected to the first connection (32) of the isolation chip (30) and at least one module-internal connection (22) of the second chip (20) is permanently connected to the second connection (34) of the isolation chip (30).

2. Multi-chip module according to claim 1, wherein - the first chip (10) is mounted on a first connector frame (50) and the second chip (20) is mounted on a second connector frame (52), and / or - wherein the predefined distance between the first chip (10) and the second chip (20) is determined depending on the potential difference between the first voltage domain and the second voltage domain.

3. Multi-chip module according to one of the preceding claims, wherein - the first chip (10) has a control circuit (60), - the second chip (20) has a driver circuit (70), and - the multi-chip module is set up to transmit a control signal (S) generated by the control circuit (60) via the isolation chip (30) to the driver circuit (70) of the second chip (20) for control of the driver circuit (70).

4. Multi-chip module according to one of the preceding claims, wherein - the first voltage domain represents voltages up to 5 V, preferably up to 10 V and more preferably up to 20 V, and / or - the second voltage domain represents voltages from 200 V to 10 kV, more preferably from 300 V to 10 kV and even more preferably from 400 V to 10 kV.

5. Multi-chip module according to one of the preceding claims, wherein the galvanically isolating coupling element (40) - at least one capacitor, and / or - at least one transformer, and / or - at least one optocoupler.

6. Multi-chip module according to one of the preceding claims, wherein the isolation chip (30) comprises a plurality of coupling elements (40).

7. Multi-chip module according to any of the preceding claims, wherein the multi-chip module comprises a plurality of isolation chips (30), each of which is configured to enable signal transmission and / or power transmission between the first chip (10) and the second chip (20).

8. Multi-chip module according to any of the preceding claims, wherein the multi-chip module has a housing (80) which encapsulates the first chip (10), the second chip (20) and the isolation chip (30) together.

9. Multi-chip module according to one of the preceding claims, wherein the isolation chip (30) is configured to be mechanically connected to the first chip (10) via at least one first blind contact bump and to the second chip (20) via at least one second blind contact bump, which are not intended for signal transmission and / or power transmission between the first chip (10) and the second chip (20).

10. A method for manufacturing a multi-chip module comprising: - a first step to arrange a first chip (10) which is configured to be inserted into a first voltage domain and a second chip (20) which is configured to be inserted into a second voltage domain, at a predefined distance from each other, wherein the second voltage domain has a potential difference to the first voltage domain, - a second step for arranging an isolation chip (30) on the first chip (10) and the second chip (20), wherein at least a first terminal (32) of the isolation chip (30) is aligned with a corresponding module-internal terminal (12) of the first chip (10) and wherein at least a second terminal (34) of the isolation chip (30) is aligned with a corresponding module-internal terminal (22) of the second chip (20), wherein the isolation chip (30) has at least one galvanically isolating coupling element (40) through which signal transmission and / or power transmission between the first terminal (32) and the second terminal (34) of the isolation chip (30) is enabled, and - a third step to permanently electrically connect the first terminal (32) of the isolation chip (30) to the module-internal terminal (12) of the first chip (10) and to permanently electrically connect the second terminal (34) of the isolation chip (30) to the module-internal terminal (22) of the second chip (20) based on a flip-chip assembly.

Images