It has been widely known that colloidal particles and their arrayed structures play a critical role in various fields because of their versatility. Based on an expectation that quadrupole microstructures would display unique optical characteristics, we focused on the fabrication process for quadrupole structures composed of colloidal particles. The quadrupole structures consisted of polystyrene particles (PSt) with 1 μm diameter were formed by applying the approach integrated with a top-down method and a bottom-up method. Microhole arrays with two different shapes, circular holes and square holes, were fabricated on a Si substrate by using electron beam lithography and reactive ion etching. These top-down processes were followed by a bottom-up process that Si substrate with the fabricated microhole arrays was withdrawn from PSt aqueous solution. With the guide of the microhole arrays, the PSt particles were forced to array the specific structures in the microholes by the capillary force and van der waals force acting on particles and substrate. These spontaneous driving forces, which are attributed to self-assembly phenomenon, have an essential role in the process of microstructure building. Consequently, quadrupole structures were fabricated; additionally, the distance between two neighboring particles consisting of quadrupole structures could be controlled by the sizes of microhole, and the obtained particle configurations could be taken off onto an adhesive tape.
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