Measurement Techniques for Three-Dimensional Metrology of High Aspect Ratio Internal Features—A Review

Abstract

Non-destructive measurements of high aspect ratio microscale features, especially those with internal geometries such as micro-holes, remain a challenging metrology problem that is increasing in difficulty due to the increasing requirement for more complexity and higher tolerances in such structures. Additionally, there is a growing use of functional surface texturing for improving characteristics such as heat transfer and wettability. As a result, measurement techniques capable of providing dimensional form and surface finish for these features are of intense interest. This review explores the state-of-the-art inspection methodologies compatible with high-aspect-ratio structures and their suitability for extracting three-dimensional surface data based on identified high-aspect ratio structure types. Here, the abilities, limitations, challenges, and future requirements for the practical implementation and acceptance of these measurement techniques are presented.

Dynamic three-dimensional measurement by spatial-domain phase-shifting method based on fringe projection profilometry

“…Utilizing Eq. ( 17) and the actual subfringes intensity I k test ðx; yÞ, we can derive the least-square errors for each pixel E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 1 9 ; 1 1 7 ; 5…”

“…Fringe projection profilometry (FPP) [1][2][3][4] is one of the most important three-dimensional (3D) measurement techniques, which enables non-contact and high-precision surface reconstruction and finds applications in diverse fields such as industrial design, 5 solid mechanics, 6 and medical orthopedics. 7 The phase calculation process in FPP can generally be categorized into two approaches: the multi-frame method 8 and the transform-based method.…”