Fluidic Self-assembly and Self-interconnection of Microscopic Chips

• Applicants: Professor Dr. Heiko Jacobs; Dr.-Ing. Johannes Reiprich
• Subject Area: Microsystems ; Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Joining and Separation Technology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 536407281

Background and Motivation: The production of almost all human-designed electronic products use robotic processes to arrange and connect electronic parts. While robotic machines dominate the manufacturing world there are applications where the established processes of serial pick and place, manipulation of single objects, or wire bonding, reach scaling limits. An example of this is found in applications that require efficient arrangement and connection of microscopic chips (with side lengths in the 1 - 100 micrometer window) with high precision or in large quantiles. Inspired by nature, self-assembly based manufacturing processes are considered a potential solution. However, so far successful self-assembly experiments of chips onto surfaces with yields approaching 100% have only worked well with fairly large chips (side lengths of at least 100 micrometers or 1,000,000 cubic millimeters in volumetric terms). Truly microscopic chips remain a challenge and electrical connection is often not part of the reported solutions. As such an assembly/interconnection gap remains. Objectives: The fundamental goal of this research is to close this gap. In contrast to the commonly used robotic methods, the project focuses on controllable engineered fluidic self-assembly. The focus is on capturing of microcopic chips and self-interconnection. Within this field, two challenges remain. The first challenge is to reduce the minimum chip size while maintaining a high assembly yield exceeding 99.9% (Objective 1). Specifically, previously developed methods and platforms are not working at the proposed scale; the yield to capture the chips drop dramatically. For example, attempts to assemble microscopic LEDs with 5000 times smaller volume (e.g.: 10x10x2 micrometers side lengths, 200 cubic micrometers) failed. Insights require a new experimental chamber and experiments to uncover the relevant parameters. The second challenge is to establish solutions that enable self-interconnection. The goal is to increase the number of electrical contacts (Objective 2, chips with more than one contact). Objective 3 involves applying the acquired knowledge to assemble microscopic LEDs onto advancing substrates. Merit: The proposed research program, involves fundamental investigations of relevant elements such as assembly forces, receptor and binding site designs, component designs, transport, mechanical excitation, and other parameters yet to be revealed. The scientific merit lies in developing a knowledge base that enables the "engineering and energy landscaping" of self-assembly and self-interconnection processes, with a focus on "microscopic components with more than one electrical contact".

• DFG Programme: Research Grants