Dispense and self-planarization process on a modified surface for multiple height 3-D microfabrication

A photoresist dispense and self-planarization (DSP) approach as a simple and cost-effective photoresist coating method has been exercised on a surface property modified substrate, where the oxygen plasma treatment of a substrate through a shadow mask selectively modifies the open area to a hydrophilic property. The non-plasma-treated area repels the dispensed photoresist while one on the plasma treated surface spontaneously spreads out to the boundary between the plasma treated and not-treated surface, allowing to form pre-defined polymer islands. Photoresist islands with various thicknesses on a single substrate have been successfully demonstrated by dispensing an appropriate amount of photoresist on each area with its dimension known. Also photoresist has been tilted to some degree to obtain a non-planar surface and a pillar array with multiple heights has been demonstrated.