Microstructuring of Dual Damascene Opening by Hot Embossing Combined with Etch-Back Process

Abstract

In this study, we demonstrate a process to form dual damascene opening in a poly(chloro- p-xylylene) (parylene-C)/Si sample based on hot embossing. First, the hot-embossing conditions of parylene-C were established for a given mold geometry. The pattern in the Ni mold was replicated by hot embossing with good fidelity under the following conditions: temperature, 305 °C; press force, 500 N; and holding time, 300 s. By lowering the initial layer thickness of the parylene-C film, we can decrease residual layer thickness to an acceptably low level. Etch-back tests of the embossed parylene-C/Si samples were then performed by reactive ion etching (RIE) at various RF powers, pressures, and flow rates, using different etching chemicals (O2, O2/SF6, O2/CHF3). Their results demonstrated that the use of O2/CHF3 plasma (60 sccm O2, 25 sccm CHF3) offers the lowest dimensional change of the pattern and the best quality of the etched surface. Finally, a dual damascene opening was fabricated in a parylene-C/Si sample by parylene-C hot embossing, followed by RIE with O2/CHF3. The developed process allowed for a marked reduction in time and cost, compared with the standard photolithographic dual damascene.