A High Aspect Ratio, Flexible, Transparent and Low-Cost Parylene-C Shadow Mask Technology for Micropatterning Applications

In this paper, we present a flexible parylene-C shadow mask technology for creating microscale patterns on flat and curved surfaces. The smallest feature size of 4 μm is demonstrated and the technology is scalable up to full wafer size. With the addition of SU-8 pillars, we also demonstrate multi mask processing with an alignment accuracy of about 5-6 μm. To achieve the smallest features, a low temperature and high aspect ratio (>8:1) parylene etch process is also developed. Utilizing this shadow mask, we successfully patterned proteins and cells on various surfaces (glass, PDMS, methacrylate) up to 9 times. This technology has potential applications for patterning proteins, cells and organic transistors on conventional and/or unconventional substrates.