| AVS 66th International Symposium & Exhibition | |
| Atomic Scale Processing Focus Topic | Tuesday Sessions |
| Session AP+EL+MS+PS+SS+TF-TuA |
| Session: | Advancing Metrology and Characterization to enable Atomic Layer Processing |
| Presenter: | Christophe Vallee, LTM, Univ. Grenoble Alpes, CEA-LETI, France |
| Authors: | C. Vallee, LTM, Univ. Grenoble Alpes, CEA-LETI, France M. Bonvalot, LTM, Univ. Grenoble Alpes, CEA-LETI, France B. Pelissier, LTM, Univ. Grenoble Alpes, CEA-LETI, France J-H. Tortai, LTM, Univ. Grenoble Alpes, CEA-LETI, France S. David, LTM, Univ. Grenoble Alpes, CEA-LETI, France S. belahcen, LTM, Univ. Grenoble Alpes, CEA-LETI, France V. Pesce, LTM, Univ. Grenoble Alpes, CEA-LETI, France M. Jaffal, LTM, Univ. Grenoble Alpes, CEA-LETI, France A. Bsiesy, LTM, Univ. Grenoble Alpes, CEA-LETI, France R. Gassilloud, CEA-LETI, France N. Posseme, CEA-LETI, France T. Grehl, IONTOF GmbH, Germany P. Bruner, IONTOF GmbH, Germany A. Uedono, University of Tsukuba, Japan |
| Correspondent: | Click to Email |
Innovation in materials, architectures (3D), gap filling technologies, lithography and etch processes are mandatory at every node of CMOS or memory devices. These challenging integration issues can be facilitated by the use of an integration scheme currently being intensively investigated known as area selective deposition (ASD). Criteria for an adequate area selective deposition process are: growth only on specific regions, high throughput compatible with industrial demands, no so-called mushroom profiles into adjacent features as well as no nuclei defectivity on undesired sites. Several routes can be developed to achieve an ASD process with ALD. The one discussed here concerns the deposition/etch approach which takes benefit from an in situ etching step inserted in a standard ALD cycle [1]. By incorporation of anisotropic or isotropic etching steps in the ALD process, “surface” selective deposition, as well as topographically selective deposition (TSD) have been obtained [2, 3]. The major current shortcoming of this approach lies in the deep insight which is required regarding elementary atomic-scale reaction mechanisms. Indeed, in the case of an ALD/ALE Area Selective Deposition process, a highly precise control of etching and its selectivity at the atomic scale is needed. Controlling the nature and density of defects induced by etching or passivation steps and understanding their impact on the physical and electrical properties of selectively deposited films are of course also required. Moreover, in order to optimize these processes, an accurate understanding of the underlying reasons why passivation after a low number of ALD cycles, is no more effective. Thus, in situ as well as ex situ monitoring and metrology are mandatory.
In this presentation, we will discuss how to optimize and understand atomic-scale reaction mechanisms in an ALD/ALE ASD process using combined in situ or ex situ measurements, such as ellipsometry, XPS, XRR, LEIS, FIB-STEM, and positron annihilation. We will show that when crosslinked, these technics are very effective to perform atomic scale metrology and characterization. As an example, we will discuss F atom localization and density in selectively deposited oxides thanks to a F-based ALE chemistry incorporated in the ALD process. In the case of a topographically selective deposition (TSD) process attempts will be presented to understand ion/surface interactions when low energetic ions are extracted from the plasma of the PEALD reactor both during deposition and plasma-ALE steps.
[1] R. Vallat et al, JVSTA 35 (2017) 01B104
[2] R. Vallat et al, JVSTA 37 (2019) 020918
[3] A. Chacker et al, APL 114 (2019)