Laser Transmission Bonding of Silicon-to-Silicon and Silicon-to-Glass for Wafer Level Packaging and Microsystems

• Published in: ECS transactions Vol. 16; no. 8; pp. 561 - 568
• Main Authors: Sari, Fahri, Wiemer, Maik, Bernasch, Michael, Bagdahn, Joerg
• Format: Journal Article
• Language: English
• Published: 2009
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.2982911

Miniaturization in the semiconductor industry and in microsystems shows that the packaging of sensitive chips with multiple functions is becoming more and more important regarding mechanical stress induced by temperature change during the conventional bonding process. Laser Transmission Bonding (LTB) with selective heat input allows a small heat-affected zone (HAZ) along the bonding frames. The chips can thus be joined without any temperature load in the functional area on Wafer Level or Chip-Level. This paper will present first bonding results determining the joinability of silicon-to-silicon samples by applying a cw-thulium fiber laser at wavelength of 1908 nm using an absorbing intermediate layer at the interface. Furthermore, a part of a study will briefly present results evaluating the mechanical strength (burst pressure) of silicon-glass bonds by applying a cw-Nd:YAG-laser at wavelength of 1064 nm.