| AVS 60th International Symposium and Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS-WeM |
| Session: | Fundamentals of Plasma Surface Interactions |
| Presenter: | A.J. Knoll, University of Maryland, College Park |
| Authors: | N.A. Fox-Lyon, University of Maryland, College Park D. Metzler, University of Maryland, College Park A.J. Knoll, University of Maryland, College Park T. Lii, Texas Instruments D. Farber, Texas Instruments G.S. Oehrlein, University of Maryland, College Park |
| Correspondent: | Click to Email |
New methods for shrinking lateral features are required to extend current generation photoresist patterning to smaller structures for devices. One approach for this is deposition onto sidewalls of patterned features using plasma-etch equipment. Current issues with this method are creating significant and uniform (x,y dimensions) pattern shrinkage and minimizing roughness and deformation of patterned features. In this work, we explored shrinking circular/elliptical holes and lines in 248 nm photoresist and 193 nm films using plasma-enhanced deposition in combination with etching. Both hydrocarbon and fluorocarbon plasma mixtures with inert/reactive carrier gases were evaluated for deposition. Plasma parameters for shrinkage were chemistry (e.g., ratio of deposition gas to carrier gas flow), pressure, applied power, ion energy (by substrate biasing), and deposition time. Real-time in situ ellipsometry and x-ray photoelectron spectroscopy of deposited films and scanning electron microscopy of patterns were carried out for characterization. We report on the plasma parametric dependencies of top-down and sidewall deposition rates, along with optical density and chemical composition of the films. Cyclical deposition/etching and pulsed plasmas were also explored for achieving shrink and minimizing sidewall roughness. Statistical analysis of x:y shrink, top-down deposition to sidewall deposition, and sidewall/surface roughening was investigated. We find strong dependencies on sidewall shrink on feature size and aspect ratios. As feature sizes get below 50 nm, minimizing feature roughness/occlusion becomes more difficult for the plasma parameters explored. Achieving significant 1:1 x:y sidewall shrink requires fine control of the plasma parameters that can change during deposition. By fine-tuning plasma parameters we have achieved 10’s of nm of 1:1 x:y sidewall shrink of circular/elliptical patterned photoresist features.