Periodic Reporting for period 2 - HEATPACK (new generation of High thErmAl efficiency componenTs PACKages for space)
Berichtszeitraum: 2020-01-01 bis 2023-03-31
Keeping the components as cold as possible has a huge impact on their performance and reliability, a complex task for electronic devices with increasing functionalities within decreased footprints, leading to greater power densities to handle. While 50% of electronics failures at least are related to thermal issues, effective thermal management is paramount to improve the devices mean time to failure and therefore the overall reliability, particularly in space products where systems have to operate for missions of up to 15 years without any chance of being repaired.
In this context, the HEATPACK project team developed critical technology building blocks for enabling high power components transformative packages with very low thermal resistance for space applications.
This includes Metal-Diamond-based composite materials for use as package baseplate, benefiting from Diamond’s outstanding thermal properties. Various metal-diamond composites, consisting of silver or copper matrix, were thus developed, with tailored properties for subsequent integration into power electronic packages.
A focus has also been put on improving the Thermal Interface Materials (TIM) connecting together the main elements of a packed device. These interfaces play an equally important role in the overall performance. Two products have been developed: a sintered silver paste, demonstrating very good thermal efficiency i.e. about two times better than the best soldering material currently in use, and an adhesive film, featuring thermally and electrically conductive properties with performances close to that of commercial references.
More advanced solutions have also been studied, such as active cooling of components through micro heat pipes integrated in silicon substrate. This procedure has been shown to be very effective, with performance levels that in theory are even better than those of the best existing bulk or composites materials. The project enabled a reliable manufacturing process to be put in place for this type of cooler, and to confirm that it operates correctly when a heat source is activated.
Precisely characterizing the thermal performance of these technologies remains a challenge, in this regard, a new method (FDTR) has been developed, including a dedicated test bench and associated analysis software. The instrument has been successfully implemented as its accuracy has been demonstrated on standard materials but as well on the ones developed within the consortium.
Ultimately, these building blocks have been combined to define two different high thermal efficiency packages. Electrical demonstrators have been produced in order to test the modules under representative conditions, confirming the potential of the technologies, especially the very good thermal performances achieved. Reliability tests finally allowed to assess the suitability of the solutions for use into space applications, making it possible to envisage an integration in flight model products in the short to medium term.
A Silver sintered paste formulation has been developed at Warsaw University of Technology, to be implemented at first packaging level i.e. for die to heatsink assembly, demonstrating very good thermal efficiency. This development was carried out in collaboration with a local SME in Poland, therefore having the necessary resources to industrialise this solution and bring it to market in the case of a technology transfer.
A new process is now in place at Adamant Composites for advanced adhesive film solutions, both electrically and/or thermally conductive, to be used as a TIM at second level i.e. package to structure assembly for instance. Through the dissemination activities, feedbacks from interested customers have already been collected, and trials beyond the project are also planned to further improve the product.
RHP Technology optimized four different diamond-based composite grades exhibiting state-of-the-art thermal performances, as well as tailored mechanical properties suitable for an implementation in a high power component’s package. The maturity level reached allows putting these materials to the space market, while non-space customers have been attracted as well.
The CSEM aims to continue increasing the maturity of active coolers beyond the project, indeed this technology has tremendous potential: not only can the integrated micro heat pipes extract even more heat than the best-performing materials, but it is also possible to implement them as close as possible to the active zones of power components, thereby enabling optimum cooling.
Regarding thermal measurement techniques, the method successfully put in place by the University of Bristol is leading to the commercialisation of a FDTR system that has already started.
Through the development of the two packaging solutions introduced in the project, Egide and Alter UK greatly extended their capabilities, which can be applied to other component encapsulation approaches, for needs other than those of the space industry.
Finally, the solutions have gone through electrical and thermal tests in conditions representative of actual space equipment sections, confirming the initial expectations notably in terms of thermal performances. The reliability tests carried out at Alter Spain allowed to bridge an important maturity gap, highlighting the potential of the technologies for operating in harsh environments.
Beyond these first markets, the outcomes of HEATPACK could have wider and different fallouts. While the project has primarily focused on space applications, the consortium partners aim to bring the technologies to other markets, as some of the building blocks could definitely be used in terrestrial applications.
Apart from products competitiveness considerations, the project contributes to propose 100% European packaging solutions, reducing the dependence on these critical technologies and capabilities. This is part of the wider goal of securing a European supply chain for high-power, high thermal efficiency packages.