Self-alignment of microchips using surface tension and solid edge

The purpose of this research is to develop a self-alignment mechanism using surface tension and solid edge for tiny microchips package. The solid edge of a rectangular protrusion replaced the surface treatment, which is usually used in the self-alignment technology. The experiments result showed that the commercial Radio Frequency Identification (RFID) microchip could be accurately auto-aligned on the protrusion. The edge effect, which confined the droplet spreading, is stronger than the boundary of hydrophilic and hydrophobic surface generated by the surface treatment. The standard deviation of aligned position was smaller than 16 mu m when the surface area of water droplet on protrusion was near to the bottom area of RFID microchip. The self-alignment completed in a tenth of a second. There was no visible position shift on aligned RFID microchip after suffering the simulated motion of transportation. The self-alignment mechanism in this paper can begin a new era of an innovative microchip package process without extra requirement on the microchips. (c) 2007 Elsevier B.V. All rights reserved.