Advances in Low-Temperature Bonding Technologies for 3D Integration

• Guest Editors
• Tadatomo Suga (University of Tokyo)
• Naoteru Shigekawa (Osaka City University)
• Eiji Higurashi (University of Tokyo)
• Hideki Takagi (AIST)
• Kazuhiko Shimomura (Sophia University)

Since the observation of Newton's rings in optical contacts, the technologies of bonding, or the adhesion of two objects, have made great progress in terms of their applications, methodologies, and related areas of fundamental science. Among the various bonding methods, those involving low-temperature bonding (LTB) are important because of their application to the fabrication of systems with low tolerances against thermal stresses and their short turnaround time. LTB is now leading to entirely new manufacturing approaches to three-dimensional (3D) and heterogeneous integration, not only for semiconductor devices and microsystems but also for energy systems and power devices; LTB-based micro-electro-mechanical-system modules such as pressure sensors and acceleration sensors have been developed and are now commercially available. The possibilities of 3D-LSIs, hybrid ICs, and tandem solar cells, as well as engineering substrates for optical and power devices using LTB technologies are currently being investigated. Novel methods of LTB and the characterization of bonding interfaces have been continuously proposed and their validity has been examined.

Given that R&D activities related to LTB are performed in a wide range of technological fields, their achievements have been published in separate journals. Under such circumstances, the aim of this edition of Selected Topics in Applied Physics (STAP), "Advances in Low-Temperature Bonding Technologies for 3D Integration", is to summarize the present status of LTB technologies. We believe that the future prospects of this cutting-edge technology can be observed through the 20 papers published in this edition, which will hopefully play an essential role of exploring the frontiers of LTB technologies.

We are grateful to the "3D Integration by Low-temperature Bonding Technology" Research Committee for their cooperation in preparing this edition of STAP.

• Tadatomo Suga
• Naoteru Shigekawa
• Chief Guest Editors