Sequential self-assembly of micron-scale components with light

We present a versatile and flexible method to sequentially self-assemble micron-scale components at specific locations onto unconventional substrates, such as glass and plastic. In this method, components are independently batch fabricated and assembled onto a series of receptor sites incorporated onto a substrate in a fluid medium. Initially, all self-assembly sites are blocked with a photoresist polymer. Controlled light exposure can be used to remove the polymer and make a site available for receiving a microcomponent. By repeating this procedure, various microcomponents may be integrated onto specific locations on the substrate. To demonstrate the process, we prepared four types of 20 mu m thick, 320 mu m diameter circular silicon components and showed their optically controllable self-assembly in arrays of 640 receptor sites on glass and plastic with yields reaching 85%. The integration and operation of two types of functional components, red light-emitting diodes and silicon resistors, on plastic substrates was also demonstrated.