| AVS 62nd International Symposium & Exhibition | |
| Selective Deposition as an Enabler of Self-Alignment Focus Topic | Thursday Sessions |
| Session SD+AS+EM+PS-ThA |
| Session: | Process Development for Selective Deposition and Self-aligned Patterning |
| Presenter: | Joshua Ballard, Zyvex Labs |
| Authors: | D. Dick, University of Texas at Dallas J. Ballard, Zyvex Labs J. Randall, Zyvex Labs Y.J. Chabal, University of Texas at Dallas |
| Correspondent: | Click to Email |
Atomic layer deposition (ALD) has become an important process step in semiconductor manufacturing, where the self-limiting nature of each step of the process permits atomic scale control over the ultimate layer thickness in addition to relatively fast processing with high pressure reactors. However, it has been shown that ALD can be used to selectively deposit material onto patterned surfaces, requiring not only saturation of each deposition cycle in desired areas but also suppression of deposition in those areas where it is undesirable. One mechanism for improving practical selectivity would be to find the minimum exposure that is saturates the growth where desired in order to avoid excess overall reaction probability in areas where inhibited growth is preferred.
To investigate this, we have examined the deposition in vacuum (“UHV ALD”) of Al2O3 and TiO2 with TMA and TiCl4, respectively, on both hydrophobic, H-terminated Si(100) surfaces and hydrophilic OH-terminated Si(100) surfaces prepared by H2O exposure of clean Si(100)-(2x1) surfaces. Surface reactions and relative coverages are determined by in-situ IR spectroscopy, and ex-situ XPS. We find that good selectivity can be achieved at 150oC. Preliminary data and calculations also suggest that an initial wetting layer of TMA on clean Si(100) promotes subsequent growth of TiO2 or other high-k dielectrics. Finally, we will discuss how these findings have made it possible to develop a full multi-cycle process for a custom low-pressure ALD system equipped with scanning tunneling microscopy and atomic force microscopy.