A general strategy of in-situ warpage characterization for solder attached packages with digital image correlation method. (June 2017)

• Record Type: Journal Article
• Authors: Niu, Yuling; Wang, Huayan; Park, S.B.
• Is Part Of: Optics and lasers in engineering. Volume 93(2017)
• Page Start: 9
• Page End: 18
• Publication Date: 2017-06
• Subjects: 3-D digital image correlation -- In-situ measurement -- Warpage characterization -- Solder ball attached packages -- Facet size and step -- Image correlation quality; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2017.01.008
• Languages: English
• ISSNs: 0143-8166

Abstract

Abstract: Recently, 3-D Digital Image Correlation (DIC) is widely applied to the reliability analysis of electronic packages, which particularly characterizes the in-situ deformation of ball grid array (BGA) packages. During the image correlation procedure, many parameters influence the accuracy and data integrity of measurement result. Facet (subset) size is the principal parameter and has been studied with much effort. However, the solder balls, which are built on the substrate surface, make the scenario different with the conventional 3-D DIC experiment for the planar samples. The undulant surface generates more obstacles for the successful image correlation. In order to summarize an effective solution of 3-D DIC measurement method for solder balls attached packages, camera angle, facet size and facet step are studied with different BGA packages and different stereoscopic camera systems to achieve the best correlation quality. Also, a novel surface treatment method is introduced to guarantee the surface speckles are generated uniformly on the fluctuant surface. Highlights: This work provides the solution to measure the warpage of BGA packages with solder balls attached with DIC method. The camera angle effect of 3-D DIC system is studied, which is always ignored before. Besides the systematic errors, the optimal selection of facet (subset) size and step is given for BGA packages. The solution of facet size is a ratio consists of the solder ball effect, not a certain number.