In general, the invention regards the field of power electronics. More specifically, the invention regards a procedure for integrating electronic power chips that allows parallel production. The invention also regards devices and electronic power modules obtained by implementing the above-mentioned procedure.
The integration of electronic power chips for the production of circuits is a sequential process, in essence. It results from rather high production times, depending on the circuits, which can have a significant impact on costs. Parallelizing a production process is a well-known solution to reduce production time and increase volumes, but it often requires heavy investment if there is no technological progress to facilitate it.
Electronic power circuits, such as power modules, have a strong presence in many sectors, such as transport, industry, lighting, and heating, among others. With the desired shift toward renewable energy and energy that produces less CO2 emissions, electronic power will be more widely used and will have to respond to growing economic and technological constraints. For example, in the area of transport, the automobile industry is subject to very strict pollution emission standards that have led to the technological transformation and the electrification of vehicles. The electrification of vehicles, in the context of heavy restrictions on weight, traffic, and cost that predominate this mass production industry, requires technological progress in the procedure for integrating electronic power chips.
In the current state of the art, it is common to use HDI (High Density Interconnect) technology to increase the level of integration and reduce the size of power modules. The HDI technology generally implemented on the PCB (Printed Circuit Board) circuits is based on an optimization of the spatial implantation of the components but using, in particular, thinner interconnect ribbons and interconnect micro-holes, called microvias. Laser beam piercing is used as well as different welding techniques, such as brazing or transient liquid phase bonding (TLP bonding) or powder sintering of metallic nanoparticles.
It is also common to pile up printed circuit cards to make 3D architectures. Thus, application DE102014010373A1 proposes an electronic module that includes the first and second printed circuit cards superimposed on one another, each including an electronic component. A sintering procedure is used to connect the cards. Furthermore, application US2016/133558A1 describes a power module including a central printed circuit card that is sandwiched between two heat-dissipating plates. Electronic components are installed in the central card.
HDI technology, however, is limited with regard to the cost reductions needed for mass production and for increasing the level of integration and compactness. Indeed, certain techniques used, like piercing by laser beam, do not make it easier to parallelize the production process and are an obstacle to price reduction.
The level of integration that is possible to obtain is limited by the volume occupied by interconnects with ribbons and microvias. These interconnects with ribbons or cables introduce parasitic inductances that resist higher switching or chopping frequencies. In order to reduce the heat generated and protect the circuit from potentially destructive power surges, we must reduce the parasitic inductances. But the increase in the switching frequencies favors compactness, particularly in power convertors.
The growth of the level of integration and the compactness of the electronic power modules accent the thermal constraints on the components. Effective cooling is needed to maintain the temperatures of the active components below critical values in order to reach a thermal equilibrium and guarantee reliability of the power modules. For this, the architecture of the power modules and the technologies used must make it possible to extract the energy dissipated as close as possible to the components.
It now appears desirable to offer a new technology that would allow advances in parallel production of integrated power electronic devices, such as power modules, as well as in the integration of the electronic chips and the compactness of the devices.