A non-destructive and fast optical solution for characterization of high aspect ratio and isolated 3D hard disk drive writer head air bearing surface structure is presented in this paper. While 2D gratings are plagued by line bending and accuracy problems, the 3D scatterometry test structures show superior mechanical stability and device resemblance necessary for an accurate measurement capability at a reactive ion etch process step enabling further ion mill shape predictability prior to a point of no return in the process. The scatterometry post RIE measurement on the 3D test targets show R^2 about five times better than dual beam FIB and a correlation slope roughly 3 times closer to unity. The post RIE scatterometry wafer sigma is in average 49% of the post RIE FIB sigma and 77% of the post ion mill FIB sigma.

Date Published: 10 April 2013
PDF: 8 pages
Proc. SPIE 8681, Metrology, Inspection, and Process Control for Microlithography XXVII, 86811S (10 April 2013); doi: 10.1117/12.2011616

Published in SPIE Proceedings Vol. 8681:
Metrology, Inspection, and Process Control for Microlithography XXVII
Alexander Starikov; Jason P. Cain, Editor(s)