Microstructure fabrication on a β-phase PVDF film by wet and dry etching technology

Abstract

We report a method of fabricating microstructures directly on a thin β-phase polyvinylidene fluoride (PVDF) film without losing much of its piezoelectricity by employing wet and dry etching technologies. The piezoelectricity of PVDF depends greatly on the temperature, as is generally known. The process conditions, including the PVDF temperature history, were evaluated in experiments where there was almost no change in the PVDF film piezoelectric constant below 60 °C per 4 h. The constant of d33 in the range above 60 °C per 4 h linearly deteriorated with the rise in temperature by 0.3 × 10−12 (C N−1) °C−1 and at a temperature of 100 °C per 4 h; deterioration of about 50% was confirmed. The N,N′-dimethyl acetamide (DMA: C4H9NO) solution was used as the etchant for wet etching, and O2 plasma was used for the reactive ion etching (RIE). Tens to a hundred micrometer microstructures were easily fabricated with the proposed approach. The fabrication process technology and experimental results are also reported in detail.