Concepedia

Self-alignment of silicon chips on wafers: A capillary approach

Jean Berthier, Kenneth A. Brakke, François Grossi, L. Sanchez, L. Di Cioccio

Journal of Applied Physics · 2010 · 54 citations · 11 references

TL;DR

Three‑dimensional integration is becoming essential as Moore’s law slows, and die‑to‑wafer assembly is a critical step, but robotic methods struggle with speed and accuracy; self‑assembly offers parallelism that can overcome these limitations. The study aims to understand the mechanisms of self‑alignment using an evaporating droplet technique. The authors examine stable and unstable alignment modes and use the SURFACE EVOLVER simulation to investigate causes of chip misalignment on wafers. They propose precautions to achieve suitable alignment.

Abstract

As the limits of Moore’s law are approached, three-dimensional integration appears as the key to advanced microelectronic systems. Die-to-wafer assembly appears to be an unavoidable step to reach full integration. While robotic methods experience difficulties to accommodate fabrication speed and alignment accuracy, self-assembly methods are promising due to their parallel aspect, which overcomes the main difficulties of current techniques. The aim of this work is the understanding of the mechanisms of self-alignment with an evaporating droplet technique. Stable and unstable modes are examined. Causes for misalignments of chips on wafers and their evolution are investigated with the help of the SURFACE EVOLVER numerical software. Precautions for suitable alignment are proposed.