Title :
Novel at-design-rule via-to-metal overlay metrology for 193-nm lithography
Author :
Ueno, Atsushi ; Tsujita, Kouichirou ; Kurita, Hiroyuki ; Iwata, Yasuhisa ; Ghinovker, Mark ; Kassel, Elyakim ; Adel, Mike
Author_Institution :
Lithography Technol. Group, Renesas Technol. Corp., Hyogo, Japan
Abstract :
The effect of scanner aberrations on pattern placement errors (PPE) in the copper interconnect lithography process is studied both in simulations and experimentally. A new grating-based overlay mark, advanced imaging metrology, enables measuring device feature overlay. It is shown that the grating mark exhibits superior performance over conventional box-in-box marks. A comparison between grating-based optical and direct CD scanning electron microscopic (SEM) device overlay measurements was done. Both CD SEM and grating mark optical measurements show sensitivity to PPE. Good matching between the new grating target and device overlays was demonstrated.
Keywords :
aberrations; copper; interconnections; lithography; optical microscopy; scanning electron microscopy; semiconductor process modelling; 193-nm lithography; Cu; advanced imaging metrology; conventional box-in-box marks; copper interconnect lithography process; device feature overlay; direct CD scanning electron microscopy; grating based optical microscopy; grating based overlay mark; grating mark; grating target; pattern placement errors; scanner aberrations; via-metal overlay metrology; Copper; Electron optics; Gratings; Lithography; Metrology; Optical devices; Optical imaging; Optical microscopy; Optical sensors; Scanning electron microscopy; AIM; Advanced imaging metrology; PPE; annular illumination; conventional illumination; low contrast; low-$k$ materials; overlay metrology; pattern placement error; process robustness; scanner aberrations;
Journal_Title :
Semiconductor Manufacturing, IEEE Transactions on
DOI :
10.1109/TSM.2004.831926
