Multiscale modeling for SiO₂ atomic layer deposition for high-aspect-ratio hole patterns

Abstract

A multiscale simulation model is developed for optimizing the parameters of SiO 2 plasma-enhanced atomic layer deposition of high-aspect-ratio hole patterns in three-dimensional (3D) stacked memory. This model takes into account the diffusion of a precursor in a reactor, that in holes, and the adsorption onto the wafer. It is found that the change in the aperture ratio of the holes on the wafer affects the concentration of the precursor near the top of the wafer surface, hence the deposition profile in the hole. The simulation results reproduced well the experimental results of the deposition thickness for the various hole aperture ratios. By this multiscale simulation, we can predict the deposition profile in a high-aspect-ratio hole pattern in 3D stacked memory. The atomic layer deposition parameters for conformal deposition such as precursor feeding time and partial pressure of precursor for wafers with various hole aperture ratios can be estimated.

Sticking probabilities of H2O and Al(CH3)3 during atomic layer deposition of Al2O3 extracted from their impact on film conformality

“…Comparing experimentally obtained thickness profiles with simulated profiles can provide the initial sticking probability s 0 of the used ALD reactant, as shown for instance by Rose and Bartha 12 and Ylilammi et al 14 Here, s 0 indicates the sticking probability toward the initial surface on which all reaction sites are still available. In several models, e.g., ballistic, 8,31-35 continuum, 14,[36][37][38] and Monte Carlo, 9,10,12,27,30,[39][40][41][42] it is observed that s 0 governs the slope of the leading front of the thickness profile. In this work, the relation between the slope of the profile front and the initial sticking probability has been quantified using the continuum model reported by Yanguas-Gil and Elam 36 to directly determine sticking probabilities from ALD thickness profiles without further modeling.…”

Review and future perspective of feature scale profile modeling for high-performance semiconductor devices

“…For recent 5 years, useful simulation techniques have been adopted to the ALD process. Miyano et al 96 Qu et al 98 developed a detailed SiO 2 -PEALD model with the cycle of SiH 2 ½NHðC 4 H 9 Þ 2 precursor [called bis(tertiary-butylamino)silane (BTBAS)] step and Ar∕O 2 plasma step using a cell removable method. A CCP reactor with a 300 mm diameter and gap length of 1.5 cm was assumed.…”

Tunable Atomic Layer Deposition into Ultra-High-Aspect-Ratio (>60000:1) Aerogel Monoliths Enabled by Transport Modeling

“…To understand the ALD coating process on high-aspect-ratio structures and determine the processing conditions needed for conformal coverage, a variety of models have been developed, including analytical/continuum approaches, ,− kinetic Monte Carlo simulations, , ballistic simulations, and multiscale modeling. − A recent review by Cremers et al as well as a book by Yanguas-Gil provide comprehensive overviews of many of these efforts. , Well-defined high-aspect-ratio structures, such as LHAR structures and AAO, are often used to experimentally measure ALD infiltration and assist in the development of diffusion and reaction models. ,, The analytical model by Gordon et al has been used extensively and offered a starting point for numerous other efforts . This model predicts a necessary precursor exposure, defined by the product of the exposure time and precursor partial pressure in the deposition chamber, which is necessary to coat a structure of a specific aspect ratio.…”

“…Studies by Lankhorst et al. and Miyano et al modeled the transient depletion of the precursor concentration in the reaction chamber in a constant-flow ALD process. , Grillo et al modeled ALD on nanoparticles and micrometer-scale nanoporous particles in a fluidized-bed reactor to optimize precursor utilization …”

“…50 Studies by Lankhorst et al and Miyano et al modeled the transient depletion of the precursor concentration in the reaction chamber in a constant-flow ALD process. 46,47 Grillo et al modeled ALD on nanoparticles and micrometer-scale nanoporous particles in a fluidized-bed reactor to optimize precursor utilization. 51 Despite the variety of approaches used in previous studies, most modeling efforts to date have considered continuous flow and purging of ALD precursors.…”