Electromagnetic analysis for optical coherence tomography based through silicon vias metrology

Abstract

This article reports on progress in the analysis of Time-Domain Optical Coherence Tomography (OCT) applied to the dimensional metrology of Through Silicon Vias (TSV, vertical interconnect accesses in silicon, enabling 3D integration in micro-electronics) and estimates the deviations from earlier, simpler models. The considered TSV structures are 1D trenches and circular holes etched into silicon with a large aspect ratio. As a prerequisite for a realistic modelling, we work with spectra obtained from reference interferograms measured at a planar substrate, which fully includes the dispersion of the OCT apparatus. Applying a rigorous modal approach, we estimate the differences to a pure ray tracing technique. Accelerating our computations, we focus on the relevant fundamental modes and apply a Fabry-Perot model as an efficient approximation. Exploiting our results, we construct and present an iterative procedure based on the minimization of a merit function, which concludes TSV heights reliably, accurately and rapidly from measured interferograms.

Research on EMC Optimization of Wireless Electric Field Sensor for Rail Vehicle

“…In other words, the input and output technical data and data transmission of various sensors are the important content of truly and effectively evaluating the qualification of sensors [2]. The electromagnetic compatibility of the sensor refers to the adaptability of the sensor in the electromagnetic environment, the ability to maintain its inherent performance and complete the specified functions [3]. At present, many researches on the electromagnetic compatibility performance of traditional railway track have been relatively mature and comprehen-sive, and the relevant standards are becoming more and more mature.…”

Use of the Airy beam to extend the micro-hole measurement range of an OCT system

“…In the field of industrial measurements, the problem regarding the measurements of samples with large aperture ratios in the existing OCT systems must be solved. In 2019, Iff used time-domain OCT to detect through-silicon vials with aspect ratios in the range of 0.56-6.84 [23]. Compared with Bessel beam, Airy beam have stronger main lobe energy and are associated with higher energy utilisation.…”

Screening of spherical moulds manufactured isotropically in plasma etching conditions

“…[4][5][6][7][8] Researchers have actively worked on anisotropic etching chemistry, explaining the etching parameters' effect on the profile. [4,[9][10][11] Many dry etching techniques result in anisotropic etching profiles, [12] but some can produce isotropic silicon etching, such as techniques based on chemistries: xenon difluoride (XeF 2 ), [13,14] sulfur hexafluoride (SF 6 ) plasma, [15][16][17][18] and/or wet etching by using an aqueous solution [19,20] such as Hydrofluoric acid-nitric acid-acetic acid HNA composed of hydrogen fluoride (HF*), nitric acid (HNO 3 ), and acetic acid (CH 3 COOH). [21][22][23] The latter produces the smoothest spherical cavities than the XeF 2 or SF 6 .…”