| Autor: |
Ramachandran, Koushik, Ready, W., Raj, P., Sundaram, Venky, Tummala, Rao |
| Předmět: |
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| Zdroj: |
Journal of Materials Science: Materials in Electronics; Apr2014, Vol. 25 Issue 4, p1687-1695, 9p |
| Abstrakt: |
Insulation failures from electrochemical migration is a major reliability concern for achieving reliable small conductor spacings in glass fiber reinforced substrates in the presence of humidity and DC bias voltage. In this study, insulation reliability of fine-pitch copper plated-through-vias in two different halogen-free epoxy substrates was investigated using accelerated testing condition (85 °C, 85 % RH and 100 V DC). The test vehicles included two different conductor geometry: (1) through-via to through-via (spacing: 100 and 150 μm) and (2) through-via to surface-trace (spacing: 75 μm). In accelerated testing, the through-via to through-via test vehicles exhibited insulation failures (failure criterion: 1 MΩ) with a strong dependence on via spacing with through-via spacing of 100 μm showing significantly shorter time to failures compared to test vehicles with spacing of 150 μm. Failure analysis revealed cracking in resin-glass fiber interfaces and within the resin matrix between the failed through-vias. The through-via to surface-trace test vehicles, on the other hand, did not exhibit failures based on the 1 MΩ criterion. However, occurrence of electrochemical migration was visible after optical inspection of the test vehicles. Elemental characterization revealed the presence of copper and chlorine in the resin-glass fiber interface, similar to the previously reported chloride-containing conductive anodic filament compound in printed wiring boards. Accelerating testing and failure analysis in this study indicates a strong dependence of insulation reliability on conductor spacing, geometry and substrate material properties. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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