New Y-based getter films for MEMS vacuum packaging – Get-Yt
High performance thermal imagers, such as microbolometers arrays for IR cameras, and high Q resonant micro and nano devices (reference clocks, inertial, pressure and mass sensors, etc) are enclosed in microcavities (1-10 µl) that must be maintained under low vacuum (=10-3 mbar) for more than 10 years to limit or control thermal insulation losses or viscous air damping during their operation lifetime. In advanced low temperature wafer-level packaging processes, this is achieved by using sealing materials and processes able to obtain a very high hermeticity, and by integrating getter films in the microcavity to trap desorbed gases and air leaks by sorption. The getter film must be, during or after the sealing process, thermally activated to diffuse the surface passivating species (oxygen, carbon, nitrogen) in the bulk and get a reactive surface. This project aims to study new thin film materials presenting getter properties compatible with the next generations of MEMS packaged under vacuum.
It involves 3 academic laboratories: C2N, IM2NP and CEMHTI, which have complementary know-how and knowledge in MEMS technology, XRD and ion beam analysis respectively, and ULIS Company which is the European leader in the fabrication of infrared uncooled imagers for civil and military applications.
In the frame of this project, we aim:
(i) to address the next challenge for packaging industry, i.e. to propose a getter able to sorb hydrogen and hydrocarbons at low bonding temperature, thanks to a new Y-based alloys family
(ii) to develop in-situ characterization techniques in specific environment of gas, pressure and temperature for the analysis of getter materials in terms of structure and stress (XRD), surface analysis (XPS), bulk diffusion of O, H and N (RBS-NRA-ERDA) and sorption kinetics and capacity (specific UHV multi-chamber equipment). In the particular case of NRA, the sorption/desorption of hydrogen and methane will be analyzed by using deuterium and DH4.
(iii) to model the diffusion and sorption processes as a function of the physico-chemical properties of materials, which will be the bases for future works in this domain.
(iv) to validate the results by integrating the films in microcavities with an industrial process, allowing continuous pressure measurement in the cavity and comparative residual gas analysis.
(v) to valorize the project through scientific publications, patents and/or transfer of results and developed processes to ULIS Company.
In addition, beyond scientific results expected during this project, the consortium will be a real opportunity to create in France a pole of expertise on getter materials, which know-how and knowledge will cover from the understanding of the involved phenomena to the industrial integration, through the characterization.
Monsieur Johan Moulin (Centre de Nanosciences et de Nanotechnologies)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
C2N Centre de Nanosciences et de Nanotechnologies
IM2NP Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
CEMHTI Conditions Extrêmes et Matériaux : Haute température et Irradiation
Help of the ANR 628,221 euros
Beginning and duration of the scientific project: February 2020 - 42 Months