Scatterometry-based defect detection for DSA in-line process control

Abstract

Successful implementation of directed self-assembly in high volume manufacturing is contingent upon the ability to control the new DSA-specific local defects such as "dislocations" or "line-shifts" or "fingerprint-like" defects. Conventional defect inspection tools are either limited in resolution (brightfield optical methods) or in the area / number of defects to investigate / review (SEM). Here we explore in depth a scatterometry-based technique that can bridge the gap between area throughput and detection resolution. First we establish the detection methodology for scatterometry-based defect detection, then we compare to established methodology. Careful experiments using scatterometry imaging confirm the ultimate resolution for defect detection of scatterometry-based techniques as low as <1% defect per area sampled - similar to CD-SEM based detection, while retaining a 2 orders of magnitude higher area sampling rate.