Authors: J. Berthier, K. Brakke, L. Sanchez, L. Di Cioccio
Affilation: CEA-LETI, France
Pages: 528 - 531
Keywords: self-alignment, 3D microelectronics, restoring force, restoring torque, pinning, spreading
3D integration appears as the key to advanced microelectronic systems. 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 the current techniques. We investigate a self-assembly method based on capillary alignment. In a preceding paper we have focused on the alignment in a quasi-steady state, assuming that the liquid droplet has spread and is pinned along the edges of the chip and pad [1-2]. A similar approach has also been followed by Lambert et al. . It has been shown that the fully wetted state produces a precise alignment. However, experiments have shown that this quasi steady state is an ideal case which is not always reached due to defects in spreading or overspreading. In this work we focus on the progressive spreading and wetting of the two surfaces and analyze the consequences on the alignment. Our approach is both experimental and numerical, with an emphasis on the numerical modeling.