Microcertec, a pioneer in this approach
Since its creation in 2004, Microcertec has been enhancing its precision-machined technical ceramic parts through their metallization in thin layers. The object is then to selectively engrave the metal layer by laser (laser ablation) in order to produce a 3D interconnection circuit (CI3D) on the ceramic. The customer assembles components with integrated circuits such as MEMS, lasers, LED, CCD, SDD, etc. This innovative packaging makes it possible to meet performance requirements in severe environments, particularly in the field of on-board systems (inertial units, lidar, camera cooled thermal, atomic clock, etc.) or even high-tech instrumentation (Raman spectrometry, X-rays, passive telecommunications network, etc.).
The CI3D is therefore a real circuit made in hybrid microelectronic technology, a guarantee of robustness and reliability, but on which the components are positioned freely in space, and has mechanical functions to simplify assembly and integration operations. . The idea is not new, it comes from the CI3D on a plastic base which is shaped by molding; hence the English acronym 3D-MID for '3D Molded Interconnect Device'. Associated with the more recent concept of mechatronics and the emerging field of printed electronics due to the additive nature of its manufacturing processes, the development of 3D-MID dates back to the 1990s and has developed today on volume markets, mainly mobile telephony (GSM antenna) and automotive (sensors). We will come back to the interests of the concept later.
Regarding the process used by Microcertec, its relevance lies in the sequential association of its expertise in precision machining of technical ceramics, in microelectronic quality thin-film metallization, and in laser engraving on 3D parts. The result is a flexible technology that covers the needs of both rapid prototyping and medium-series production (a few thousand to a few tens of thousands per year). Due to its specificity, laser expertise has been integrated at Microcertec and a technical partnership has been developed for the metallization of technical ceramics. Initially modest, this activity has grown in importance, it now represents between 10 and 15% of turnover and finds most of its customers outside France, in niche markets, in the field. space, civil and military aeronautics, telecommunications, scientific and medical instrumentation.
The CI3D, what interest?
As mentioned previously, the concept of the CI3D stems from a need for freedom of placement of components in space and the addition of mechanical functions to simplify assembly operations and meet space constraints. Another benefit is the ease of testing subsets. For their part, compared to plastics, technical ceramics and precision machining win the decision when the application requires high mechanical precision and also in the relative placement of components, dimensional stability at high temperature, good electrical insulation. , dielectric properties for Radio Frequency applications, thermal conduction (aluminum nitride), a good surface condition and metallization giving access to the assembly processes used in hydride microelectronics, the possibility of tight passage or the hermetic sealing of the packaging. The gains of this association are functional performance, compactness and weight reduction, but also reliability and cost. It is not for nothing that a CI3D is found in the seismometer currently on Mars!
The CI3D of the future is revealed
The development prospects are under study. Ultra-short lasers already allow more fineness and selectivity of etching both for the metallization and the ceramic itself. This makes it possible to densify the circuits with a better resolution to achieve tracks of width less than 50 µm with a pitch less than 100 µm, or for the performance of microwave circuits with chip cavities that are not possible. to achieve otherwise than with this type of laser. In order to widen the field of applications of CI3D and in a complementary manner to the possibilities of current technology, the ceramic support like the metallization of CI3D are also intended to evolve towards additive processes which are currently in full emergence; thus opening access to the design of parts with an internal structure, multilayer circuits, integrating vias holes, passive components, sensors and also 'printing' the wiring of the chips. Microcertec is preparing for this as a technological partner for customers looking for a new generation of CI3D. (link: with a doc pdf section of the site: to see).
Authors: Pascal Métayer - Head of laser micro-machining & projects, Alain Charbonnier - Technical sales director