Modeling of deep etching of Silicon using Bosch Process a
a
a
b
Guillaume Le Dain , Ahmed Rhallabi , Fabrice Roqueta , Mohamed Boufnichel
b
Institut des Matériaux Jean Rouxel,2 rue de la Houssinière , Nantes cedex 3,
[email protected] and
[email protected] , France b STMicroelectronics, 10 rue Thalès de Millet , Tours cedex 2,
[email protected] and
[email protected] , France
Microelectronics nowadays needs to create high aspect ratio trenches in Silicon for the use of Systems In Package (SIP) or the development of Through-Silicon Via (TSV). One technique for this kind of deep etching of silicon is Bosch Process [1]. Bosch process uses alternance between an etching pulse of SF6 plasma and a deposition pulse of C4F8 plasma for creation of highly anisotropic trenches. Furthermore plasma etching techniques have great advantages, high reproducibility and fastness of etching. Therefore understanding of Bosch Process mechanisms is of big interest for industrials. To study the Bosch Process, we developed a model based on multiscale approach [2]. First, a global 0D model give information as fluxes of species and electronic temperature by simulate kinetics of SF6 and C4F8 plasmas with reactor parameters as pressure and power. This data are used as entries for both sheath model and surface model. Sheath model, based on Monte-Carlo algorithm, simulate ion transport trough the sheath, sheath is the electronic depletion area between plasma and substrate surface. The Ion Energy and Angular Distributions Functions (IEADF) obtain by this simulation serve as data entries for surface model. Surface model uses both fluxes of species and IEADF to simulate the plasma-surface interaction. This model uses a Monte-Carlo-like algorithm to simulate phenomena as chemical etching by adsorption of fluorine, physical etching by sputtering of ions or chemical deposition of fluorocarboned polymer on the substrate. At the end, we obtain profiles which demonstrate high accuracy with deep trenches profiles visualized by SEM images and we have only needed to send engine parameters of reactor to the model. References 1. 2.
F. Laermer, A. Schilp, K.Funk and M.Offenberg in IEEE Int. Conf. On MEMS (1999) pp. 211-216 A. Pateau Simulation Multi-échelle de la gravure profonde du Silicium par Procédé Bosch Ph. D Thesis, Université de Nantes, 2014
