Localized selective deposition of oxides for microelectronics

Published : 1 January 2023

In order to reduce the manufacturing costs of integrated circuits and continue their miniaturization, disruptive approaches based on the use of selective deposition processes are now being considered in addition to photolithography. Recent developments are mostly linked to the use of atomic layer deposition (ALD) which is a very suitable technique for the development of a selective process due to its high sensitivity to surface chemistry. ALD is a thin film deposition method based on the self-limited adsorption on a surface of gas phase precursors and surface reactions between precursor molecules and a reagent, allowing atomic-scale control of the thickness and quality of the deposited material.

The objective of this thesis concerns the development of a localized selective deposition (ASD for Area Selective Deposition) based on the use of an organic layer allowing the deactivation of surface chemical reactions in ALD. This organic layer should act as an inhibition layer of ALD which allows selective deposition by zone. In the literature, this approach generally uses self-assembled monolayers (SAM) which may have limitations in terms of density and thermal or chemical stability. In this project, we will focus on the development of inhibition thin films deposited by vapor-based processes with the aim of finding a versatile method to allow the selective deposition of metal oxides. In addition to the selectivity with ALD deposits, the selection criteria will be the thermochemical stability of the inhibition layer in order to support the ALD process conditions as well as the possibility of depositing thick oxide layers.

During this thesis, the PhD student will have access to several deposition techniques (ALD, PECVD, iCVD) as well as to a rich nano-characterization platform (ellipsometry, FTIR, contact angle, AFM, XPS, Tof-SIMS). These surface analyzes and thin film characterizations will allow to identify the best approach in order to obtain the highest possible selectivities. Fine characterization of organic and inorganic films at the nanoscale will also be carried out on patterned structures. One objective of this work will be also to highlight the mechanisms at the origin of selectivity as well as defect formation. Finally, the ASD process will be implement for the realization of an (opto) electronic demonstrator.

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