Novel CD inspection technology leveraging a form birefringence in a Fourier space
A new technology was developed to detect Critical Dimension (CD) variations in a Fourier space. The detection principle is a form birefringence of the wafer. Utilizing this principle, CD and Pattern E...
Linewidth roughness and cross-sectional measurements of sub-50 nm structures with CD-SAXS and CD-SEM
Critical dimension small angle X-ray scattering (CD-SAXS) is a measurement platform that is capable of measuring the average cross section and sidewall roughness in patterns ranging from (10 to 500) n...
Experimental quantification of reticle electrostatic damage below the threshold for ESD
Proc. SPIE, Vol. 6922, 69221Y (2008);
doi:10.1117/12.760480
Online Publication Date: 24 March 2008
Conference Date: Monday 25 February 2008
Conference Location: San Jose, CA, USA
Conference Title: Metrology, Inspection, and Process Control for Microlithography XXII
Conference Chairs: John A. Allgair, Christopher J. Raymond
Thedamage mechanisms that take place when a reticle is subjectedto electrical stress by exposure to an electric field havebeen investigated by applying voltage directly to the structures ina special test reticle. Surface current was recorded at alllevels of stress from 1V to 100V. The current/voltage characteristicwas polarity dependent and exhibited increasing non-linearity as the featurespacing was reduced. Atomic Force Microscopy showed that the electricalstress caused EFM (Electric Field induced Migration of chrome), matchingthe damage seen in reticles stressed through induction by anexternal electric field. No ESD events were recorded, confirming thatEFM is independent of ESD and that it occurs withlower electrical stress. The threshold for EFM was found tobe five times lower than the previous estimate, starting at1V with 1m spacing. Damage caused by EFM was shownto be continuous, cumulative and the rate of CD degradationwas measured to be from 3 to 6 nm persecond.