Improvement of electrical properties of through silicon vias metal interconnector by adding single-walled nanotubes

A novel through silicon via (TSV) interconnector, which consists of tin (Sn) powder and single-walled nanotube (SWNT) powder, is proposed and characterized. Most conventional TSV structures, which are commercially available to integrate multiple chips on one packaging, utilize electroplated copper as the interconnector. However, the electroplating-based process has some drawbacks, such as highly demanding fabrication processes in high-aspect-ratio vias, numerous voids, and high cost. To avoid these issues, we used Sn powder mixed with SWNTs as TSV interconnector. SWNTs have been added to improve the electrical properties of TSVs filled only with Sn. The electrical resistance of Sn powderfilled TSVs is 44.59Ω, but it is markedly decreased to 5Ω when a Sn and SWNTs mixture (weight ratio of SWNTs : Sn = 0:5 : 1) was used as the TSV interconnector. In addition, the proposed method could be used for various applications owing to its low process temperature.