전사 인쇄에 의한 3차원 백금 다공성 다층구조

Three-dimensional and Multilayered Structure Prepared by Area of Platinum Transfer Printing

Abstract

A three-dimensional porous structure was fabricated by pattern transfer printing for applications of electrodes in gas sensors. To form replica patterns, solutions were mixed with acetone, toluene, heptane, and poly(methyl methacrylate). These replica patterns can also be formed on substrates such as polyimide, polydimethylsiloxane, and silicon. The wide range of line widths from 1 to $5{\mu}m$ was derived from the surface grating patterns of master substrates. The cross-bar pattern with 40 layers showed a thickness of 600 nm. The area of platinum transferred patterns with different line widths was enhanced to $20{\times}25mm$, which is applicable to various electrode patterns of gas sensors.

Fig. 1. SEM images of master pattern with line widths of (a) 1 μm, (b) 2 μm (c) 5 μm wafer etched by photolithography

Fig. 2. Schematic of transfer printing process, (a) master patterns, (b) PMMA spin coating, (c) pattern transfer, (d) Pt sputtering on protruded PMMA, (e) pattern printing, and (f) after washing process.

Fig. 3. SEM images of transfer-printed Pt lines with line widths of (a) 1 μm, (b) 2 μm and (c) 5 μm.

Fig. 4. XPS analysis of (a) untreated and (b) Ar plasma treated PTFE substrate.

Fig. 5. Schematic of stacking transfer printing process (a) & (b) and SEM images of crossed-wire structures composed of two layers of Pt lines with line widths of (c) 1 μm, (d) 2 μm and (e) 5 μm.

Fig. 6. SEM images of three-dimensional structures of 1 μm wide Pt lines with multilayers of (a) 10, (b) 20 and (c) 40 layers.

Fig. 7. Cross-sectional image of three-dimensional structure with 1 μm wide Pt wires stacked 40 layers