Large area diffraction-based inspection of submicron periodic structures

• Published in: Microelectronic engineering Vol. 86; no. 4; pp. 1025 - 1028
• Main Authors: Držík, Milan, Šatka, Alexander, Haško, Daniel, Kováč, Jaroslav, Uherek, František, Allsopp, Duncan W.E., Abbott, Steven J., Hubbard, Graham
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-04-2009; Elsevier
• Subjects: Diffraction efficiency; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Light diffraction; Moth eye; Optical diagnostics; Optical sources and standards; Optics; Periodic structures; Phase gratings; Physics; Porous alumina; Porous alumina; Diffraction efficiency; Phase gratings; Optical diagnostics; Light diffraction; Moth eye; Periodic structures; Phase grating; Atomic force microscopy; White light; Porous materials; Laser beams; Light sources; Wafers; Visible radiation; Illumination; Large scale; Diagnostic aid
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2008.12.041

An experimental study of diagnostics possibilities of periodic structures using visible light diffraction principles is presented. The goal of the study is to develop a simple method suitable for use in the inspection of large scale area periodically structured surfaces. It is shown that diffraction-based methods can be applied for surface feature size determination in the submicron region as well as for assessment of the surface profile modulation depth. In order to observe the periodic structure defects on the whole surface of 6–8 inch wafers, an optical filtration set-up is proposed using a white light illumination source. Diffraction efficiency has been acquired by photoelectric sensing of laser beam diffraction. Determined values, – of both the surface feature size and the depth of modulation coincide well with that obtained by AFM and SEM.