Large-Area Patterning of Coinage-Metal Thin Films Using Decal Transfer Lithography

Abstract

We describe two new procedures that appear to hold significant promise as means for patterning thin-film microstructures of the coinage metals (Cu, Ag, Au). A feature central to both is the modification of their surfaces to promote the adhesive transfer of PDMS thin-film microstructures, a material suitable for use as resist layers in large-area patterning, using Decal Transfer Lithography (DTL). The present work provides a significant extension of the capabilities of DTL patterning, providing general protocols that can be used to transfer decal resists to essentially any substrate surface. The first method involves the functionalization of a surface, specifically those of gold and silver films with a thiol-terminated silane coupling agent, (mercaptopropyl)trimethoxysilane. This self-assembled monolayer, when hydrolyzed to its silanol form, provides a robust adhesion-promoting layer suitable for use in DTL patterning. The second method exploits the surface chemistry provided by the deposition of a nanoscale silicon dioxide thin-film capping layer using e-beam evaporation. This procedure provides an exceptional method for patterning large-area, thin-film microstructures of Cu-one compatible with micrometer-scale design rules-that are essentially defect free. Both surface modification strategies enable high-quality poly(dimethylsiloxane) decal transfers, and as the current work shows, these structures are suitable for large-area micrometer-sized patterning of gold, silver, and copper thin films via both wet-etching and lift-off procedures.

Fabrication of Flexible Binary Amplitude Masks for Patterning on Highly Curved Surfaces

“…Next, the gold surface is treated with 3-mercaptopropyl trimethoxysilane (MPTMS) to facilitate its permanent adhesion to a subsequently deposited layer of PDMS. [58][59][60] In order to create transparent patterns in the opaque gold layer, a PDMS channel system is first bonded to the MPTMS layer on gold and an iodinebased gold etch solution is subsequently pulled through them by aspiration. After flushing with water and drying, the channels are filled with clear PDMS (Fig.…”

“…To do so, we take advantage of the ability of UV-ozonetreated b-PDMS to make an irreversible adhesive bond to oxidebearing materials surfaces (i.e., SiO 2 , PDMS, quartz). [31,32,60,68,69] We have not specifically characterized the surface chemistry of UV-ozone-treated b-PDMS, but note that it appears to respond similarly to etchants and oxidants as does PDMS. Figure 6 schematically represents the steps involved in the simultaneous fabrication of two opposite tone masks by Method III.…”

Plasmonics in Biology and Plasmon-Controlled Fluorescence

“…Various nanofabrication methods have been used to produce a variety of metal shapes bound to substrates [84][85][86]. Figure 24 shows an electron micrograph of nanotriangles on a glass substrate [86].…”

A Viscoelastic Model for the Rate Effect in Transfer Printing

“…contributed equally to this work. their growth (donor) substrate via an elastomeric stamp, and then prints them onto a different (receiver) substrate [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Recent rapid progress in the field has significantly expanded the range of materials used for patterning and their applications.…”