AVS 52nd International Symposium
    Thin Films Wednesday Sessions
       Session TF+EM-WeM

Paper TF+EM-WeM3
Real-time Sensing for Process Dynamics and Metrology in Tungsten Atomic Layer Deposition

Wednesday, November 2, 2005, 9:00 am, Room 310

Session: In-Situ/ Ex-Situ & Real- Time Monitoring
Presenter: L. Henn-Lecordier, University of Maryland
Authors: L. Henn-Lecordier, University of Maryland
W. Lei, University of Maryland
G.W. Rubloff, University of Maryland
Correspondent: Click to Email
Atomic layer deposition (ALD) has been investigated using a novel wafer-scale reactor which features an internal mini-reactor and in-situ mass spectrometry (MS) for chemical analysis during tungsten ALD using WF6 and SiH4. Downstream MS sampling system measures deposition kinetics directly and reaction product MS signal is used for real-time thickness metrology. MS signal reveals ALD reactant and product species in real time through ALD process cycle, with product generation and reactant depletion indicative of species consumption. Both the H2 product from SiH4 exposure and the SiF4 product from WF6 exposure show the kinetics of self-limiting adsorption/reaction on the surface, which enables process optimization to minimize cycle time. MS data also directly indicates the influence of process temperature and precursor dose on film growth, and can also been employed for process optimization. The integrated reaction product MS signal over each exposure, when plotted against ALD cycle number, reveals different stages of ALD film growth and provides a quantitative measure of film thickness. Our study demonstrated that integrated reaction product MS signal has a good linear relationship with ALD film thickness. This provides a promising approach to advanced process control in ALD manufacturing.