Surface profile and stress field evaluation using digital gradient sensing method. (9th August 2016)

• Record Type: Journal Article
• Authors: Miao, C; Sundaram, B M; Huang, L; Tippur, H V
• Is Part Of: Measurement science & technology. Volume 27:Number 9(2016:Sep.)
• Publication Date: 2016-08-09
• Subjects: optical metrology -- speckle correlation -- surface slopes -- stress gradients -- surface topography -- stress evaluation; Physical measurements -- Periodicals; Scientific apparatus and instruments -- Periodicals; Equipment and Supplies -- Periodicals; Science -- instrumentation -- Periodicals; Technology -- instrumentation -- Periodicals; Mesures physiques -- Périodiques; Physical measurements; Scientific apparatus and instruments; Periodicals; 502.87
• DOI: 10.1088/0957-0233/27/9/095203
• Languages: English
• ISSNs: 0957-0233

Abstract

Abstract: Shape and surface topography evaluation from measured orthogonal slope/gradient data is of considerable engineering significance since many full-field optical sensors and interferometers readily output such a data accurately. This has applications ranging from metrology of optical and electronic elements (lenses, silicon wafers, thin film coatings), surface profile estimation, wave front and shape reconstruction, to name a few. In this context, a new methodology for surface profile and stress field determination based on a recently introduced non-contact, full-field optical method called digital gradient sensing (DGS) capable of measuring small angular deflections of light rays coupled with a robust finite-difference-based least-squares integration (HFLI) scheme in the Southwell configuration is advanced here. The method is demonstrated by evaluating (a) surface profiles of mechanically warped silicon wafers and (b) stress gradients near growing cracks in planar phase objects.