Dresden 2014 – scientific programme

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DS: Fachverband Dünne Schichten

DS 35: Poster I: Application of thin films; Focus session: Sensoric micro and nano-systems; Focus Session: Sustainable photovoltaics with earth abundant materials; Graphen (joint session with TT; MA; HL; DY; O); Ion and electron beam induced processes; Layer properties: electrical, optical, and mechanical properties; Magnetic/organic interfaces, spins in organics and molecular magnetism; Micro- and nanopatterning (jointly with O); Organic electronics and photovoltaics (jointly with CPP, HL, O); Thermoelectric materials

DS 35.43: Poster

Wednesday, April 2, 2014, 17:00–20:00, P1

Stress Analysis on Copper Through Silicon Vias with Micro-Raman Spectroscopy — •Parisa Bayat¹, Dietmar Vogel², Raul D. Rodriguez¹, Evgeniya Sheremet¹, Sven Rzepka², Bernd Michel², and Dietrich R. T. Zahn¹ — ¹Technische Universität Chemnitz, Semiconductor Physics, D-09107 Germany — ²Fraunhofer ENAS, Micro Materials Center, D-09126 Chemnitz, Germany

Most through silicon vias (TSVs) are filled with copper. The coefficient of thermal expansion of copper (c.a. 16-17 x10⁻⁶ /^∘C) is around six times higher than that of silicon (c.a. 2.7 x10⁻⁶ /^∘C). Therefore, temperature loadings on Cu-TSV lead to a very large local thermal expansion mismatch between copper and silicon/dielectric (e.g. SiO₂). This imposes very large stresses and strains in the vicinity of the interface region. The local strain/stress fields remaining after packaging processes can be high enough to introduce reliability issues in electronic devices. To evaluate the stress within the silicon surrounding of the TSV, micro-Raman spectroscopy is one of the most appropriate methods capable of providing local measurement of stress at high spatial resolution. We report on the analysis of the stress field in silicon adjacent to Cu-TSVs and the impact of thermal annealing in stress reduction.