| AVS 65th International Symposium & Exhibition | |
| Spectroscopic Ellipsometry Focus Topic | Monday Sessions |
| Session EL+EM-MoA |
| Session: | Spectroscopic Ellipsometry: Novel Applications and Theoretical Approaches |
| Presenter: | Shilin Ng, Nanometrics Incorporated |
| Authors: | P. Ong, Micron Semiconductor Asia Pte. Ltd., Singapore S. Ng, Nanometrics Incorporated G.B. Chu, Micron Semiconductor Asia Pte. Ltd., Singapore P. Murphy, Nanometrics Incorporated L.C. Liong, Micron Semiconductor Asia Pte. Ltd., Singapore W. Fu, Micron Semiconductor Asia Pte. Ltd., Singapore Y. Wen, Nanometrics Incorporated L.W. Ho, Micron Semiconductor Asia Pte. Ltd., Singapore |
| Correspondent: | Click to Email |
Full 4x4 Mueller Matrix Spectroscopic Ellipsometry (MMSE)[1] is a widely-used technique for measuring cross-sectional profile, critical dimensions (CD) and material thicknesses of repeating structures created as part of microelectronic device manufacturing processes. In this paper, it will be shown that its application can be extended to measuring asymmetries in such structures with off-diagonal Mueller Matrix Elements[2]. These asymmetries, such as tilt of etched holes, and lines or trenches, are typically caused by inhomogeneity in the etch plasma sheath at the wafer edge. This paper will focus on one of the most important use-cases: tilt of high aspect ratio (HAR) etched 3D-NAND channel holes. Full 4x4 MMSE can be used to provide fast, accurate, non-destructive measurements of the channel hole tilt, both in direction and magnitude.
Furthermore, in contrast to CD and thickness measurements which are typically done in metrology test keys, this tilt measurement is in-die and on-device. This allows us to characterize the tilt at all locations on the wafer edge, as well as the variation in tilt as the wafer edge is approached. In addition, we also show how the measurements can be used to monitor the condition of the etch chamber for equipment control and/or to trigger preventive chamber maintenance.