Programmable self-assembly for microsystem integration

Abstract

Department of Electrical Engineering, Department of BioengineeringThis dissertation studies and improves upon template-based self-assembly processes as a suite of techniques for microsystem integration.We first provide an updated definition for microscale self-assembly, and provide a framework that separates all self-assembly processes into three distinct phases which can be independently analyzed.A catalyst-enhanced self-assembly process is then presented, wherein non-participating 'catalyst' components are introduced to a dry-environment batch-assembly process, demonstrating 25 -50% reduction in acceleration needed to trigger part motion and up to four times increase in concentration of parts in motion due to addition of catalysts. The presence of catalytic parts allows stochastic part-to-trap assemblies to be performed at lower accelerations than without, and thus allow said assemblies to be performed further from the acceleration-levels required to free trapped parts; this reduces the probability of part-disassembly, thus improving assembly yield. A model from chemical kinetics theory is adapted for the analysis of this catalyst-enhanced self-assembly process.A variation on the prevalent methodology of driving a stochastic assembly process, using vibrations perpendicular to the assembly surface, is then presented. Using a modified actuator that introduces agitations that are in the plane of the assembly surface, unprecedented control of micropart-motion has been achieved; of note, components can be reliability induced into a "walking mode", where components are moved across surfaces in predetermined directions with a surface-hugging motion. Walking modes enables parts to be moved across surfaces and into binding sites, but do not cause trapped components to disassemble due to the suppression of out-of-plane agitation. Repeatable Finally, the magnetically aided assembly of 01005 surface mount components in a vertical pose is studied by adapting the visual-feedback systems used throughout the thesis work. Electrical performance has been verified, and our process is demonstrated to be competitive against integrated passive elements in terms of area-footprint and capacitive and resistive property-tolerances.

Template-based self-assembly for silicon chips and 01005 surface-mount components

“…Self-assembly has been defined as the autonomous organization of components into ordered patterns or structures without human intervention [4]. Specifically in the scope of microscale assembly and packaging, we add that selfassembly usually involves a stochastic transportation phase that brings discrete components to specified binding locations on a substrate, an alignment phase that correctly orients components at the binding sites and a final step that permanently adheres components to the binding locations [5].…”