AVS 46th International Symposium
    Thin Films Division Thursday Sessions
       Session TF-ThA

Paper TF-ThA7
Optical Metrology for Process Development and Control of Universal Anti-Reflective Layers

Thursday, October 28, 1999, 4:00 pm, Room 615

Session: Ex-situ Characterization
Presenter: J.M. Holden, Nanometrics, Inc.
Authors: J.M. Holden, Nanometrics, Inc.
Y. Wang, Novellus Systems
Z. Karim, Novellus Systems
K. MacWilliams, Novellus Systems
Correspondent: Click to Email
A two-layer, inorganic anti-reflective layer (ARL) consisting of a high extinction coefficient SiO@sub x@N@sub y@ bottom layer and a low extinction coefficient SiO@sub x@N@sub y@ top layer is used as a "Universal" ARL or UARL. The UARL is useful in damascene lithography or anywhere substrate reflectance is unknown or uncontrollable. The optical dispersions of individual films of the structure are characterized by Variable Angle Spectroscopic Ellipsometry (VASE@footnote 1@). Minimal parameter models are used to describe refractive index, n(@lambda@), and extinction coefficient, k(@lambda@), dispersions for top and bottom films. The dispersion models are implemented on a metrology tool that uses combined reflectance and spectroscopic ellipsometry (R+SE). Quantities relevant to DUV lithography, n(248 nm), k(248 nm), and thickness, t, are measured identically by VASE and R+SE methods. The metrology tool was used for process development and is applicable to process monitoring in a fab environment. Individual films are deposited as either a single film deposited on a single deposition station (static) or deposited in a multi-station, sequential deposition. The effect of interface layers in the sequentially deposited films can be detected weakly from ellipsometric data but not from reflectance. Normal incidence reflectance measurements and lithography simulations for typical DUV exposure tools indicate no significant differences between static and sequentially deposited films. @FootnoteText@ @footnote 1@VASE is a trademark of the J. A Woollum Company.