On 6th march 2018, Pierre Roumanille has defended his thesis. Awarded by University of Toulouse III – Paul Sabatier, his work was supervised by both CIRIMAT laboratory (CNRS/UT3 Paul Sabatier/INP), the Science de la Matière doctoral school, and IRT Saint Exupéry. The high quality and the relevance of Pierre’s thesis contributed to get significant results as a part of NANO project.
THESIS SUBJECT
“Low temperature joining materials for electronics : on the interest of metal oxalates and formiates”
About his thesis
Due to environmental and health concerns, new regulations led to a restriction in the use of lead in electronic equipment. Joining materials (based on tin, silver, copper, bismuth…) for surface-mount technology are therefore subject to many development work in order to comply with regulatory and technical requirements. The use of nanomaterials is a seriously considered way for developing low temperature joining processes for electronics. It is based on the well-known decrease of melting and sintering temperatures of nanomaterials with particle size. The potential of metal carboxylates for soldering applications has already been demonstrated. The thermal decomposition under controlled atmosphere of such precursors leads to the creation of metal nanoparticles with an increased reactivity compared to that of micron sized particles. In this context, this work of thesis presents the study of the controlled decomposition in various atmospheres of metal oxalates and formates intended to be integrated into a low-temperature lead-free joining process. The relationship between the metal particles size formed in the early stages of decomposition and their melting point was studied in detail, as well as the influence of oxidation on the evolution of metal particles size and their ability to make solder joints.
NANO Project
Developing an innovative solder paste for the assembly at low temperature of electronic components on printed circuit board taking benefit of nanometric effect.
Jury
- M. Philippe TAILHADES – CNRS/Toulouse University – PhD Advisor
- Mme Valérie BACO-CARLES – CNRS/Toulouse University – Co-Supervisor
- M. André AYRAL – Montpellier University – Examiner
- M. Marc VERELST – Toulouse University – Examiner
- M. Jean-François SILVAIN – CNRS/Bordeaux University- Rapporter
- Mme Nathalie AUDEBRAND – Rennes University – Rapporter
- M. Hoa LE TRONG – IRT Saint Exupéry – Invited
- M. Philippe MONFRAIX – Thales Alenia Space – Invited
PUBLICATIONS
P. Roumanille, V. Baco-Carles, C. Bonningue, M. Gougeon, B. Duployer, P. Monfraix, H. Le Trong, P. Tailhades : “Bi2(C2O4)3·7H2O and Bi(C2O4)OH Oxalates Thermal Decomposition Revisited. Formation of Nanoparticles with a Lower Melting Point than Bulk Bismuth”, Aug 2017, ACS Publications, Inorganic Chemistry.
P. Roumanille, V. Baco-Carles, C. Bonningue, M. Gougeon, B. Duployer, P. Monfraix, H. Le Trong, P. Tailhades : “Study of the Bismuth Oxalates Thermal Decomposition and the Low Melting Behavior of Resulting Bismuth Nanoparticles”, Nanomat2017, Budapest, 2017.
P. Roumanille, V. Baco, C. Bonningue, M. Gougeon, P. Tailhades and P. Monfraix : “Developing new joining materials for low-temperature electronics assembly”, Dec 2016, IEEE Nanotechnology Materials and Devices Conference (NMDC), France
P. Roumanille, V. Baco, C. Bonningue, M. Gougeon, P. Tailhades and P. Monfraix : “Matériaux innovants sans plomb pour l’assemblage de composants électroniques à basse température”. JNRDM 2016 (Journées Nationales du Réseau Doctoral en Micro-nanoélectronique), Toulouse (France). 2016