ELECTRONIC COMPONENT WITH TWO-PHASE FLUIDE FOR HEAT MECALORIC DISPENSING FROM SEMICONDUCERS OF AN ELECTRONIC COMPONENT

Description

Technical field

[0001] The present application relates to an electronic component comprising means for direct cooling of the semiconductors of said electronic component, in the form of a two-phase fluid circulating in contact with said semiconductors. State of the art

[0002] An electronic component according to one embodiment is shown in the figure 1. This electronic component 10 comprises a stack of copper layers 12a-d alternating with layers of a ceramic substrate 14a-c. The copper layers 12a, 12d are the outer layers of the stack. On one of the substrate layers 14b, at least one semiconductor 16 is arranged. The semiconductor 16 is electrically connected to the adjacent copper layers 12b, 12c, via solders 22. The semiconductor 16 is protected by a layer of epoxy resin 18, arranged between the substrate layer 14b on which the semiconductor 16 is arranged and an adjacent copper layer 12c. The electronic component 10 has a structure known by the English term "Direct Bonded Copper".

[0003] In order to cool the semiconductor 16, heat sinks 20 are fixed to the electronic component 10, via a thermal paste or directly soldered onto the outer copper layers, on either side of the stack of layers. Due to the position of the heat sinks 20, the thermal losses emitted by the semiconductor 16 must be evacuated through the copper 12a-d and ceramic 14a-c layers, which causes inefficiencies since said layers have a significant thermal resistance.

[0004] In addition, such heat sinks have a significant weight, which impacts the weight of the electronic component.

[0005] The present invention aims to propose an alternative solution to this method of cooling semiconductors in electronic components.

[0006] US2019 / 096780 A1 discloses an electronic component cooled by a two-phase fluid. Summary of the invention

[0007] To this end, the subject of the invention is an electronic component comprising a stack of at least first and second layers of electrically conductive material, alternating with at least a third layer of electrically non-conductive material, said third layer being arranged between said first and second layers, and comprising a first face arranged opposite and at a distance from the second layer and a second face opposite the first face arranged opposite and in contact with the first layer, a volume being defined between the first face of the third layer and the second layer.

[0008] According to the invention, the electronic component comprises at least one semiconductor arranged in said volume on the first face of the third layer and cooling means taking the form of a two-phase fluid filling said volume.

[0009] Thus, according to the electronic component according to the invention, it is devoid of an epoxy resin layer, as well as a heat sink.

[0010] Advantageously, the electronic component according to the invention has a reduced weight compared to the electronic component of the prior art, since said electronic component is devoid of heat sinks, which have a significant impact on the weight of said electronic component. In addition, the electronic component according to the invention has improved performance, in particular thanks to more efficient cooling of the semiconductors, which allows an extension of their service life, but also a better efficiency of the electronic component. Advantageously, the installation of the electronic component according to the invention is easier, since it is less bulky.

[0011] According to another characteristic, the two-phase fluid is a liquid-gaseous two-phase fluid. According to this characteristic, the volume has an inlet and an outlet, the electronic component comprises a reservoir of two-phase fluid, a pump fluidly connected between the reservoir and the inlet of said volume, the two-phase fluid circulating between the inlet and the outlet of said volume, and a condenser fluidly connected between the outlet of said volume and the inlet of the reservoir.

[0012] According to another characteristic, the liquid-gaseous two-phase fluid is included in the following list: dielectric oil, purified water, methanol, acetone, R1234 refrigerant gas and FC-7 oil.

[0013] According to an embodiment which is not part of the invention, the two-phase fluid is a solid-liquid two-phase fluid. According to this embodiment which is not part of the invention, the electronic component comprises a housing encapsulating the first, second and third layers, said housing being filled with the two-phase fluid and made of thermally conductive material.

[0014] According to this embodiment which is not part of the invention, the solid-liquid two-phase fluid is included in the following list: lauric acid, pure gallium and INERTEK microcapsules.

[0015] According to another characteristic, the electronic component is a power converter, or a switch, or an inverter, or a voltage adapter, or a current adapter. The invention also relates to an electronic system comprising at least one electronic component according to the invention, as well as an aircraft comprising at least one electronic system according to the invention. Brief description of the figures

[0016] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which: there Figure 1 is a schematic sectional view of an electronic component, which illustrates an embodiment of the prior art, the Figure 2 is a schematic sectional view of an electronic component, which illustrates an embodiment of the invention, the Figure 3is a schematic sectional view of an electronic component, which illustrates an embodiment of the invention, the Figure 4 is a schematic sectional view of an electronic component, which illustrates an embodiment which is not part of the invention, and the Figure 5 is a schematic perspective view of an aircraft comprising an electronic system, itself comprising an electronic component, which illustrates an embodiment of the invention. Detailed description

[0017] An electronic component 30 according to an embodiment of the invention is shown in the figure 2. This electronic component 30 comprises a stack of layers of electrically conductive material 32a-d, such as copper, alternating with layers of electrically non-conductive material 34a-c, for example a ceramic substrate. A first and a fourth copper layer 32a, 32d are the outer layers of the stack. The ceramic layers 34a-34c are only layers inside the stack. The first ceramic layer 34a is disposed between the first and second copper layers 32a, 32b; the second ceramic layer 34b is disposed between the second and third copper layers 32b, 32c; the third ceramic layer 34c is disposed between the third and fourth copper layers 32c, 32d. Of course, the electronic component 30 may comprise more or fewer copper layers 32a-d or ceramic layers 34a-c than those shown.

[0018] Between the second ceramic layer 34b and the third copper layer 32c, a volume 38 is defined. The second ceramic layer 34b has a first face F1 arranged opposite and in contact with the second copper layer 32b, and an opposite second face F2 arranged opposite and at a distance from the third copper layer 32c. In other words, the layers 32a, 34a, 32b, 34b are stacked in contact with each other, in this order, without a space between said layers, and the layers 32c, 34c, 32d are stacked in contact with each other, in this order, without a space between said layers, while a space is present between the layers 34b and 32c.

[0019] On the ceramic layer 34b, at the level of the second face F2, at least one semiconductor 36 is arranged. The semiconductor 36 is thus arranged in the volume 38. The semiconductor 36 is electrically connected to the second and third copper layers 32b, 32c, via solders 42. The electronic component 30 thus has a structure known by the English term "Direct Bonded Copper".

[0020] Volume 38 of this electronic component 30 is free of epoxy resin.

[0021] The electronic component 30 comprises cooling means arranged at least partly in the volume 38. These cooling means take the form of a two-phase fluid which fills the volume 38. In other words, the semiconductor 36 is immersed in the two-phase fluid which fills the volume 38. With the exception of the surface of the semiconductor 36 which is brazed onto the ceramic layer 34b, the other surfaces of the semiconductor 36 are in contact with the two-phase fluid. The two-phase fluid is arranged in the volume 38, instead of the epoxy resin used according to the prior art shown in the figure 1 .

[0022] A two-phase fluid is a phase-changing material that, depending on temperature, can change from a phase in a first state to a phase in a second state, and vice versa. For example, the two-phase fluid can be a liquid-gas two-phase fluid, or a solid-liquid two-phase fluid.

[0023] This electronic component 30 does not have a heat sink.

[0024] According to the embodiment shown in the figure 3 , the two-phase fluid is a liquid-gaseous two-phase fluid. In a non-limiting manner, the liquid-gaseous two-phase fluid may be a dielectric oil, such as HFE-7000 (Hydrofluoroether) or NOVEC ™ < 7000, purified water, methanol, acetone, R1234 refrigerant gas, or FC-7X oil. The two-phase fluid is configured to be in a liquid phase when the temperature is below a predetermined phase change temperature, and to pass into a gaseous phase when the temperature becomes higher than the predetermined phase change temperature. When the two-phase fluid is in the gaseous phase, this two-phase fluid is configured to return to the liquid phase when the temperature becomes lower than the predetermined phase change temperature.

[0025] The electronic component 30 comprises a reservoir 50 of two-phase fluid comprising an inlet 50a and an outlet 50b. In the reservoir 50, the two-phase fluid is in its liquid state. The outlet 50b of the reservoir 50 is fluidically connected to a pump 56, via a pipe 54a. The pump 56 is also fluidically connected to an inlet 38a of the volume 38, via a pipe 54b. The two-phase fluid circulates between the inlet 38a and an outlet 38b of the volume 38. The pump 56 makes it possible to pressurize the two-phase fluid from the reservoir 50, so that the two-phase fluid is sent and circulates correctly in the volume 38. The circulation of the two-phase fluid is represented by the arrows F. The electronic component 30 comprises a condenser 52 fluidically connected to the outlet 38b of the volume 38 and to the inlet 50a of the reservoir 50, respectively via pipes 54c, 54d.

[0026] When using the electronic component 30, the temperature of the semiconductor 36 increases, and the two-phase fluid circulating between the inlet 38a and the outlet 38b of the volume 38 will change from its liquid phase to its gaseous phase in order to absorb this increase in temperature and cool said semiconductor 36. More precisely, the change in phase of the two-phase fluid makes it possible to extract the thermal calories emitted by the semiconductor 36 in operation.

[0027] When the two-phase fluid in gaseous form passes into the condenser 52, the latter passes from its gaseous state to the liquid state, before being returned to the reservoir 50. The condenser 52 thus makes it possible to cool the two-phase fluid, which has absorbed the thermal calories from the semiconductor 36.

[0028] In order to cool the two-phase fluid, the condenser 52 may be in contact with the ambient air, or in contact with a secondary cooling loop.

[0029] The use of phase change cooling of the two-phase fluid makes it possible, by controlling the pressure at the outlet 38b of the volume 38 of the electronic component 30, to impose the junction temperature of the semiconductor 36.

[0030] According to the embodiment shown in the figure 4, which is not part of the invention, the two-phase fluid is a solid-liquid two-phase fluid. In a non-limiting manner, the solid-liquid two-phase fluid may be lauric acid, such as coconut oil (phase change temperature around 25°C), pure gallium (phase change temperature around 30°C), or INERTEK microcapsules (phase change temperature ranging from 5°C to 28°C depending on the microencapsulated phase change material). The two-phase fluid is configured to be in a solid phase when the temperature is below a predetermined phase change temperature, and to transition into a liquid phase when the temperature becomes higher than the predetermined phase change temperature.When the two-phase fluid is in the liquid phase, this two-phase fluid is configured to return to the solid phase when the temperature becomes lower than the predetermined phase change temperature.

[0031] The electronic component 30 comprises a housing 60 encapsulating the copper layers 32a-d and the ceramic layers 34a-c. The housing 60, and in particular the volume 38 between the second ceramic layer 34b and the third copper layer 32c, around the semiconductor 36, is filled with two-phase fluid. In the housing 60, the two-phase fluid is in its solid state. In the solid phase, the two-phase fluid provides a function of immobilizing and protecting the semiconductor 36. The housing 60 is made of a thermally conductive material, for example aluminum or copper.

[0032] When using the electronic component 30, the temperature of the semiconductor 36 increases, and the two-phase fluid present in the volume 38 will change from its solid phase to its liquid phase in order to extract the thermal calories emitted by the semiconductor 36 in operation and to absorb this increase in temperature. Then, the housing 60 is configured to thermally dissipate the calories absorbed by the two-phase fluid during the phase change. The thermal calories are then evacuated by conduction in the housing 60, then by natural convection or radiation from the housing 60 into the environment of the electronic component 30.

[0033] There Figure 5 represents an aircraft 70 in which at least one electronic system 72 is integrated comprising at least one electronic component 30 as described above.

[0034] The electronic component 30 may be, in a non-limiting manner, a power converter, a switch, an inverter or a voltage or current adapter, and more generally any electronic component comprising at least one so-called power semiconductor.

Claims

1. Electronic component (30) comprising a stack of at least first and second layers (32a-d) of electrically conductive material, alternating with at least one third layer (34a-c) of electrically non-conductive material, said third layer (34a-c) being positioned between said first and second layers (32a-d), and comprising a first face (F2) arranged facing and at a distance from the second layer (32c-d) and a second face (F1) opposite the first face (F2) arranged facing and in contact with the first layer (32a-b), a volume (38) being defined between the first face (F2) of the third layer (34a-c) and the second layer (32a-d), said electronic component (30) comprising at least one semiconductor (36) arranged in said volume (38) on the first face (F2) of the third layer (34a-c), and characterized in that said electronic component (30) comprises cooling means taking the form of a two-phase fluid filling said volume (38), the two-phase fluid being a liquid-gas two-phase fluid, the volume (38) having an inlet (38a) and an outlet (38b), and in that the electronic component (30) comprises a tank (50) of two-phase fluid, a pump (56) fluidically connected between the tank (50) and the inlet (38a) of said volume (38), the two-phase fluid flowing between the inlet (38a) and the outlet (38b) of said volume (38), and a condenser (52) fluidically connected between the outlet (38b) of said volume (38) and the inlet (50a) of the tank (50).

2. Electronic component (30) according to Claim 1, characterized in that the liquid-gas two-phase fluid is included in the following list: a dielectric oil, purified water, methanol, acetone, R1234 refrigerant gas, and FC-7 oil.

3. Electronic component (30) according to either of the preceding claims, characterized in that said electronic component (30) is a power converter, or a switch, or an inverter, or a voltage adapter, or a current adapter.

4. Electronic system (72) comprising at least one electronic component (30) according to one of Claims 1 to 3.

5. Aircraft (70) comprising at least one electronic system (72) according to Claim 4.