Overview of 3D Integration Technology and Challenges for Volume Production

摘要

Three-dimensional (3-D) integration is an emerging technology, which vertically stacks and interconnects multiple materials, technologies, and functional components such as processor, memory, sensors, logic, analog, and power ICs into one stacked chip to form highly integrated systems. Since CMOS device scaling has stalled, 3D integration technology allows extending Moore's law to ever high density, higher functionality, higher performance, and more diverse materials and devices to be integrated with lower cost. The potential benefits of 3D integration can vary depending on approach; increased multi-functionality, increased performance, increased data bandwidth, reduced power, small form factor, reduced packaging volume, increased yield and reliability, flexible heterogeneous integration. However, 3D integration technology has still many challenges for commercialization. In this paper, we describe an overview and future perspectives of the 3D integration technologies. The reliability issues of electrical and mechanical constraints induced by Cu TSV, micro-bumps, wafer thinning, and wafer bonding in the 3D thinned wafer are serious challenges for volume production. The paper focus on the local stress/strain effects induced by Cu TSV, micro-bump, and wafer thinning and the metal contamination effects induced by Cu TSV, and wafer thinning on the device reliabilities in the thinned wafer.%これまで，LSIは，半導体素子の微細化により，著しい速度で高性能化，大容量化が達成されてきた.しかし，消費電力の増大や特性ばらつきの増加などにより微細化が次第に難しくなつてきている.これらの問題を解決するためには，素子の微細化だけでなく， LSIに実装技術やMEMS技術，フォトニクス技術などの異種技術を融合して，システム全体で高性能化，高機能化をはかる新しい集積化技術が必要となる.したがって,今後のLSI開発は，素子の微細化を更に進めるMore Moore技術と，異種技術を融合するMore than Moore技術を車の両輪のようにうまく協調，共存させながら進めていくことが重要になる.本報告では，More than Moore技術を代表する技術のーつである3次元集積化技術について，現状の課題と将来の可能性について言及する。