Patterned Liquid Micro Rails for the Transport of Micrometer Sized Chips

Abstract

Transport and alignment of microscopic chips are important steps in microelectronics component integration with common approaches being pick-and-place, microfluidics, parallel transfer and self-assembly. An alternate transport approach of microscopic chips is proposed using patterned liquid micro rails as chaperones. The surface free energy and interfacial free energy minimization of all constituents enable the creation of stable pathways. This allows for chip-attachment to rails, while the liquid layer lubricates chip-sliding. Monorails, digital monorails, and digital birails are investigated for chip movement behavior. Chip position and speed can be controlled using liquid flow in closed chambers. Speeds from 10 to 400 mm s⁻¹ are achieved with translation distances as long as 50 mm. It is discovered that chips can selectively cross rail discontinuities of up to 500 µm, allowing for chip position control through a stop-and-go motion. A programmable liquid rails-based chip conveyor system is demonstrated by transporting diodes to receptor sites where they undergo self-assembly.