Si chiplet–controlled 3D modular microrobots with smart communication in natural aqueous environments

Modular microrobotics can potentially address many information-intensive microtasks in medicine, manufacturing, and the environment. However, surface area has limited the natural powering, communication, functional integration, and self-assembly of smart mass-fabricated modular robotic devices at small scales. We demonstrate the integrated self-folding and self-rolling of functionalized patterned interior and exterior membrane surfaces resulting in programmable, self-assembling, intercommunicating, and self-locomoting micromodules (smartlets ≤ 1 cubic millimeter) with interior chambers for onboard buoyancy control. The microrobotic divers, with 360° solar harvesting rolls, functioned with sufficient ambient power for communication and programmed locomotion in water via electrolysis. The interior folding faces carried rigid microcomponents, including silicon chiplets (Si chiplets) as microprocessors and micro-light-emitting diodes (LEDs) for communication. The exterior faces were able to engage in specific patterned docking interactions between smartlets. The heterogeneous integration is mass producible and affordable through two-dimensional (2D)-automated lithography and microchiplet bump-bonding processes, here shown to be compatible with subsequent autonomous 3D folding and rolling. The robotic modules functioned in natural aqueous environments, and the technology was analyzed as scalable down to microscopic dimensions. Selectively addressed communication with individual smartlets was enhanced via frequency-specific optical signals and enabled precise control, allowing each smartlet to be activated independently within a collective system. The work remodels modular microrobotics closer to the surface-rich modular autonomy of biological cells and provides an economical platform for microscopic applications.