Characterization of high density through silicon vias with spectral reflectometry

Ku, Yi-Sha; Huang, Kuo Cheng; Hsu, Wei-Feng

doi:10.1364/oe.19.005993

Cited by 25 publications

(27 citation statements)

References 6 publications

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“…It should be noted that the single obtained frequency indicates that the depth variations among the vias within the illumination area are smaller than the resolution limit of the depth variation of 0.36 μm, as we determined in Ref. 17. There is a slight broadening on the right side of the main peak, which reveals there might be vias slightly deeper than 28.51 μm within the illumination area.…”

Section: Resultsmentioning

confidence: 45%

“…14,15 In our previous studies, we demonstrated the use and enhancement of this existing wafer metrology tool by implementing a novel theoretical model and measurement algorithm for HAR TSV measurements. 16,17 TSV manufacturing process with high etch rate stages combined with efficient passivation or deposition steps have achieved nearly anisotropic shapes, with high etch rates of 5 μm/min or greater. 18,19 Good etch depth uniformity and shape requirements for 3-D integration are necessary in a high-volume manufacturing process.…”

Section: Introductionmentioning

confidence: 99%

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Spectral reflectometry for metrology of three-dimensional through-silicon vias

2014

J. Micro/Nanolith. MEMS MOEMS

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Abstract. The technology for semiconductor device packaging is rapidly advancing in response to increasing demand for smaller and thinner electronic devices. Three-dimensional chip stacking that uses through-silicon vias (TSVs) is a key area of technical focus, and the high-density TSV (HDTSV) is a major enabler of threedimensional (3-D) integrated circuit technology. The ongoing development of this novel technology has created a need for noncontact characterization. One of the main challenges for 3-D TSV metrology is measuring high aspect ratio features that limit conventional optical microscopy techniques. We demonstrate the use and enhancement of an existing wafer metrology tool, a spectral reflectometer, by developing and implementing theoretical models and measurement algorithms for inspection of HDTSVs. It is capable of measuring the depth of vias, and can also be used for the estimation of bottom roughness and bottom shapes of vias through the model fitting. Our nondestructive solution has measured TSV diameters as small as 3 μm and aspect ratios >16.5∶1. Submicron depth measurement accuracy has been verified in the range of 30 to 60 μm on via depth. Metrology results from actual wafers formed from 3-D interconnect processing are presented. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Resultsmentioning

confidence: 45%

Section: Introductionmentioning

confidence: 99%

Spectral reflectometry for metrology of three-dimensional through-silicon vias

2014

J. Micro/Nanolith. MEMS MOEMS

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“…Optical interferometry and reflectometry are the main nondestructive metrological methods for this purpose [11][12][13] but their use is limited for smaller diameter TSVs due to the requirement of obtaining a measurable signal of reflected light from the bottom of the TSV. The nondestructive 3D metrology of deep-etched structures with an aspect ratio of more than 10 and patterns with lateral dimensions in the range below 5 lm remains a challenge.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Through silicon via profile metrology of Bosch etching process based on spectroscopic reflectometry

Fursenko

Bauer

Marschmeyer

et al. 2015

Microelectronic Engineering

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“…The measurement of depths and diameters of TSVs is very important for the monitoring process during fabrication. Some researchers have tried to measure the depths and diameters of TSVs using scanning electron microscopes [1], infrared (IR) microscopes [2][3][4], diffraction phenomena [5], laser interferometry [6,7], reflectometry [8,9] and white-light interferometry [10,11]. There has been, however, very little research on the critical dimension of the bottom part of the TSV, that is, the bottom CD.…”

Section: Introductionmentioning

confidence: 99%

Methods to Measure the Critical Dimension of the Bottoms of Through-Silicon Vias Using White-Light Scanning Interferometry

Hyun

Kim

Pahk

2014

Journal of the Optical Society of Korea

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Through-silicon vias (TSVs) are fine, deep holes fabricated for connecting vertically stacked wafers during three-dimensional packaging of semiconductors. Measurement of the TSV geometry is very important because TSVs that are not manufactured as designed can cause many problems, and measuring the critical dimension (CD) of TSVs becomes more and more important, along with depth measurement. Applying white-light scanning interferometry to TSV measurement, especially the bottom CD measurement, is difficult due to the attenuation of light around the edge of the bottom of the hole when using a low numerical aperture. In this paper we propose and demonstrate four bottom CD measurement methods for TSVs: the cross section method, profile analysis method, tomographic image analysis method, and the two-dimensional Gaussian fitting method. To verify and demonstrate these methods, a practical TSV sample with a high aspect ratio of 11.2 is prepared and tested. The results from the proposed measurement methods using white-light scanning interferometry are compared to results from scanning electron microscope (SEM) measurements. The accuracy is highest for the cross section method, with an error of 3.5%, while a relative repeatability of 3.2% is achieved by the two-dimensional Gaussian fitting method.

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Characterization of high density through silicon vias with spectral reflectometry

Cited by 25 publications

References 6 publications

Spectral reflectometry for metrology of three-dimensional through-silicon vias

Spectral reflectometry for metrology of three-dimensional through-silicon vias

Through silicon via profile metrology of Bosch etching process based on spectroscopic reflectometry

Methods to Measure the Critical Dimension of the Bottoms of Through-Silicon Vias Using White-Light Scanning Interferometry

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