Regular/Temporary : Temporary
Position description :
In Imaging technologies, the microlenses are covered with a dielectric film called « Top Coat », close to a SiO2 silicon oxide. This coating improves the transmission of light in the device and protects the chips during the packaging steps. The difference in thermo-mechanical properties between this Top Coat and the underlying organic resists can lead to both integration and reliability issues.
The thesis will focus on the Top Coat / Resist stack characterizations by the nanoindentation technique along three axes:
· Temperature Young modulus measurements of the resists. Acquisition of experimental data to cross with curvature measurements.
· Quantitative measurement of the Top Coat adhesion on the resists coupling numerical modelings with nanoscratch technique. To be validated by the 4 points bending technique. Top Coat materials and pre-treatment impact to be studied.
· Toughness measurement of the Top Coat on resists. Experimental approach by nanoindentation using different tip geometries and coupling with analytical and / or numerical modeling. Impact of materials and thicknesses to be studied.
The thesis will be mainly performed at the Leti labs where specific tools are provided to acquire thermo-mechanical data. These experimental data are required for predictive simulations to localize in the Top Coat / resist stack the mechanical weaknesses by determining stress and deformation maps.
Materials Science, Mechanical skills, simulations
Finite element modeling such as COMSOL
Organization, autonomy and initiative
Synthesis and communication
Good level in English
Education level required : 5 – Master degree
Language / Level :
English : 2- Business fluent