Open AccessPrecision depth measurement of through silicon vias (TSVs) on 3D semiconductor packaging process
Author(s) -
Jonghan Jin,
Jae Wan Kim,
Chu-Shik Kang,
Jong-Ahn Kim,
Sunghun Lee
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.005011
Subject(s) - materials science , wafer , silicon , optics , through silicon via , semiconductor , femtosecond , optoelectronics , interferometry , measured depth , laser , physics , geophysics , geology
We have proposed and demonstrated a novel method to measure depths of through silicon vias (TSVs) at high speed. TSVs are fine and deep holes fabricated in silicon wafers for 3D semiconductors; they are used for electrical connections between vertically stacked wafers. Because the high-aspect ratio hole of the TSV makes it difficult for light to reach the bottom surface, conventional optical methods using visible lights cannot determine the depth value. By adopting an optical comb of a femtosecond pulse laser in the infra-red range as a light source, the depths of TSVs having aspect ratio of about 7 were measured. This measurement was done at high speed based on spectral resolved interferometry. The proposed method is expected to be an alternative method for depth inspection of TSVs.