Fabrication method of two-level polymeric microstructure with the help of deep X-ray lithography

Abstract

Two-or multi-level microstructures are getting more important in several applications such as multicomponent micro optical elements and various microfluidic systems. In the present study, a simple and efficient method is newly proposed for a fabrication of the two-level polymeric microstructures. Making a mother two-level microstructure consists of two processes: (1) the hot embossing process for a fabrication of microstructures on a PMMA substrate, and (2) the deep X-ray lithography using the hot embossed substrate for a high aspect ratio microstructure fabrication, resulting in a high aspect ratio microstructure containing smaller microstructures on its surface. Making use of so fabricated two-level microstructures as a mother structure, one could achieve a mass replication of the same microstructures via injection molding process with a metallic mold insert obtained by a nickel electroforming onto the mother microstructure. In order to demonstrate the proposed method, a polymeric high aspect ratio microstructure having smaller square microstructures on its top surface was fabricated. The fabricated two-level microstructure shows fine vertical sidewalls, which is a characteristic feature of the deep Xray lithography. In addition, a metallic mold insert for a mass replication was fabricated by a nickel electroforming process.

Replication of nanostructures on microstructures by intermediate film mold inserted hot embossing process

“…The fabrication of nano/micro combined multiscale structures becomes a quite interesting issue since there are variety of applications such as a hydrophobic film (Lee et al 2006), a dry adhesive film (Sitti and Fearing 2003;Northen and Turner 2006;Kim et al 2007), a water capturing (Parker and Lawrence 2001), and a cell culturing in tissue engineering (Gadegaard et al 2006), etc. Thus cost-effective mass production methods of such multiscale structures are increasingly in demand for practical commercialization.…”

FEM-Based Analysis of Micro-Structure Parameters for Roll Forming on Aluminum Alloy Sheet

“…In order to fabricate a few microstructures on a metal substrate, various material removal manufacturing techniques are adopted such as the LIGA technology, the laser processing technique, micro-milling, micro-cutting and grinding. These processes are effective for manufacturing micro-structures, but using the LIGA technology and the laser processing there are difficult to fabricate micro-structures on curved crosssections [3]. Moreover, it is still difficult as using these machining techniques to achieve opticalquality surfaces and precision.…”

Hard X-rays meet soft matter: when bottom-up and top-down get along well

“…4 The success of DXRL is due to the smoothness of the lateral surfaces obtained in the microfabricated materials, which is the best reported result so far for a lithographic technology with such high aspect ratio patterns. 4 Compared to competitor techniques, DXRL enables the fabrication of complex 2D, 3 multilevel 2D, 5 and 3D objects 6,7 in a faster process. The possible DXRL lateral resolution limit is in the nanoscale with potential sub-100 nm capability, and the most serious limitation for reaching this goal is given by the available masking technology (vide infra).…”