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Etude de nouvelles voies de passivation non polymérisante pour la gravure profonde du silicium

Abstract : Plasma etching of high aspect ratio structures in silicon is a key step for the fabrication of microsystems and power microelectronic devices. This thesis aimed to develop a silicon deep etching process, working at a higher substrate temperature than the cryogenic process in SF6/O2 plasma chemistry, and showing a better stability to drifts in temperature and passivating gas concentration. To this purpose, we investigated new methods of passivating the structure sidewalls by non polymerising chemistries. We studied the possibility of passivation by SO2 instead of O2. At cryogenic temperatures, etch properties are similar in SF6/SO2 and SF6/O2 plasmas. They are correlated to the neutral densities measured by mass spectrometry and actinometry. Most of the research was then dedicated to the study of SiCl4 as a passivation precursor. First we analysed the interactions between species generated in SF6/SiCl4 plasma. Characterisation experiments show that reactions on reactor walls between F radicals and SiClx species control the plasma chemistry, thereby the silicon etch properties. In SF6/O2/SiCl4 mixtures, these reactions also impact the substrate etch rate. However, the addition of SiCl4 to SF6/O2 mostly enhances lateral chemical etching. We finally studied the possibility of forming a passivation layer by SiCl4/O2 plasma at a substrate temperature of -20 °C. The results of this study enabled the development of a new process, based on alternating the etching steps in SF6 plasma with the passivation steps in SiCl4/O2 plasma.
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Contributor : Corinne Duluard <>
Submitted on : Thursday, September 3, 2009 - 4:20:17 PM
Last modification on : Thursday, March 5, 2020 - 6:48:54 PM
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  • HAL Id : tel-00413276, version 1


Corinne Duluard. Etude de nouvelles voies de passivation non polymérisante pour la gravure profonde du silicium. Physique [physics]. Université d'Orléans, 2009. Français. ⟨tel-00413276⟩



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