Depth Profiling and Cross-Sectional Laser Ablation Ionization Mass Spectrometry Studies of Through-Silicon-Vias

Grimaudo, Valentine; Moreno, Pavel; Cedeño López, Alena; Riedo, Andreas; Wiesendanger, Reto; Tulej, Marek; Gruber, Cynthia; Lörtscher, Emanuel; Wurz, Peter; Broekmann, Peter (2018). Depth Profiling and Cross-Sectional Laser Ablation Ionization Mass Spectrometry Studies of Through-Silicon-Vias. Analytical chemistry, 90(8), pp. 5179-5186. American Chemical Society 10.1021/acs.analchem.7b05313

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Through-silicon-via (TSV) technology enables 3D integration of multiple 2D components in advanced microchip architectures. Key in the TSV fabrication is an additive-assisted Cu electroplating process in which the additives employed may get embedded in the TSV body. This incorporation negatively influences the reliability and durability of the Cu interconnects. Here, we present a novel approach toward the chemical analysis of TSVs which is based on femtosecond laser ablation ionization mass spectrometry (fs-LIMS). The conditions for LIMS depth profiling were identified by a systematic variation of the laser pulse energy and the number of laser shots applied. In this contribution, new aspects are addressed related to the analysis of highly heterogeneous specimens having dimensions in the range of the probing beam itself. Particularly challenging were the different chemical and physical properties of which the target specimens were composed. Depth profiling of the TSVs along their main axis (approach 1) revealed a gradient in the carbon (C) content. These differences in the C concentration inside the TSVs could be confirmed and quantified by LIMS analyses of cross-sectionally sliced TSVs (approach 2). Our quantitative analysis revealed a C content that is ∼1.5 times higher at the TSV top surface compared to its bottom. Complementary Scanning Auger Microscopy (SAM) data confirmed a preferential embedment of suppressor additives at the side walls of the TSV. These results demonstrate that the TSV filling concept significantly deviates from common Damascene electroplating processes and will therefore contribute to a more comprehensive, mechanistic understanding of the underlying mechanisms.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute

UniBE Contributor:

Moreno, Pavel; Cedeño López, Alena; Riedo, Andreas; Wiesendanger, Reto; Tulej, Marek; Wurz, Peter and Broekmann, Peter

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

0003-2700

Publisher:

American Chemical Society

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

08 May 2018 09:49

Last Modified:

08 May 2018 09:49

Publisher DOI:

10.1021/acs.analchem.7b05313

BORIS DOI:

10.7892/boris.114850

URI:

https://boris.unibe.ch/id/eprint/114850

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