Selective deposition of silver and copper films by condensation coefficient modulation

Abstract

Patterning evaporated silver and copper films without metal removal using extremely thin printed organofluorine films to modulate metal vapour condensation.

Embedded-grid silver transparent electrodes fabricated by selective metal condensation

“…S1, S2, ESI †). This value, which is more than three times higher than previously reported for printed FTS films, 12 can be reduced to o0.05 by reducing the metal evaporation rate (Fig. S2, ESI †) although this inevitably increases the time taken to deposit the film.…”

“…1a) when the film thickness exceeds B10 nm. 12 When the FTS layer is printed as a patterned film, metal is deposited only where the highly fluorinated organic layer is not. The beauty of this approach lies in its versatility and simplicity since vacuum evaporation of metals is proven as a low cost method for making thin metal films by the packaging industry, and the shape and dimensions of the features deposited is limited only by the printing method used to deposit the patterned organofluorine layer.…”

“…Whilst the factors affecting the process of spontaneous desorption of metal atoms, and thus C, from polymer surfaces are still to be fully elucidated, 12,[18][19][20][21] the early stage nucleation studies of Faupel et al 22,23 have shown that even when C is very low there is no direct reflection of the metal atoms from soft surfaces, rather that all metal atoms are initially adsorbed. Given that siloxane linkages are well known for their flexibility, 24 and perfluorinated chains interact only very weakly with each other, it is tentatively suggested that the perfluorinated moieties in FTS films move more freely than at the surface of PFDMA which has a more rigid carbon-carbon backbone, and this movement (which is inevitably thermally activated) facilitates the ejection of weakly adsorbed Ag atoms from the polymer surface.…”

Metal Atom Desorption from Organofluorine Surfaces: What Factors Govern Desorption?

“…The physical/chemical characteristics of organic surfaces such as catalytic properties, [ 1–3 ] hydrophobicity, [ 4–6 ] and surface morphology changes [ 7,8 ] are attracting attention as new functions and are expected to be useful in developing new applications. Selective metal deposition, which was discovered on the surface of photochromic diarylethene (DAE) [ 9–12 ] and was achieved for Ag and Cu with fluorine‐based molecules [ 13–15 ] is very interesting for industrial processes, because maskless vacuum deposition is able to form desired metal patterns. The core phenomenon in selective metal‐vapor deposition is that metal‐vapor atoms are not deposited on the organic surface, that is, they are desorbed from a surface having specific physical properties.…”

Transparent Fused Nanowire Electrodes by Condensation Coefficient Modulation

“…We have recently reported that a printed layer of FTS ( Figure 1a) can have a near-zero condensation coefficient for Ag vapor when its thickness is greater than 10 nm, and so FTS can be used to fabricate patterned Ag films by condensation coefficient modulation. [11] However, the intermolecular attractive forces in organofluorines are exceptionally weak, due to the low polarizability of the carbonfluorine bond together with the relatively large intermolecular separation that results from steric repulsion between fluorine atoms. Consequently, in general, organofluorines exhibit very low surface tension and solutions of small molecule organofluorines such as FTS have a very low viscosity, making it difficult to form uniform thin films of controllable thickness above 10 nm.…”