Two reactors (STS, Oxford Estrelas) are dedicated to the deep anisotropic etching of Si allowing to realize the Bosch switched process (step time up to 10 ms) and the cryogenic process (continuous etching in the mixture of SF6/O2 in the temperature range -70°C to -150°C). The resource carries out developments on the choice of masks (optical resin, e-beam resin, SiO2 or Si3N4) in collaboration with the lithography resource. The presence of electrostatic and mechanical clamps for 3'' and 4'' allow us to manage etchings on samples from a few mm (bonding) to 4″. SOI etchings can also benefit from an anti-notching device.

Deposits of organic thin films under vacuum are also proposed (parylene, pentacene,...).

- Variation of the etching profile, such as the angle of the etching flanks, by adjusting the oxygen content in the SF6/O2 mixture in cryogenic etching.


1.  Change of etching angle with the variation of oxygen rate in cryogenic process

- Deep anisotropic etchings with very low sidewall roughness by cryogenic process. Generally used for optoelectronic component realization as a replacement for Bosch etching for this reason.


- Bosch process for creating membranes, especially on SOI, with stress control, thin thicknesses, or even drilled membranes. Typically used for MEMs or BioMEMs applications.

gravure Bosch

3. Réalisation d’un HF MEMs pour l’AFM par gravure Si Bosch (Équipe NAM6)

– Gravures profondes et très denses par procédé Bosch, telles que µ-piliers ou µ-tubes. Gravure possible jusqu’à 100 µm de profondeur sur des diamètres des tubes de 2 µm-3 µm et pitch de 1 µm. Utilisé notamment dans les applications de stockages d’énergie.

Bosch process

4. etching of microtubes diameter 2µm, pitch 1µm in Bosch process (CSAM group, C. Lethien, RS2E)

Expertise and know-how: other

- Silicon substrate feedthrough in Bosch process

– Dépôts de couches conformes de C4F8 sur tout type de surface dont nanofils. Utilisation en tant que fonctionnalisation de surface pour augmenter l’angle de contact dans les applications microfluidiques, bioMEMs,…