Area-Selective Molecular Layer Deposition with High Patterning Selectivity

Area-selective molecular layer deposition (AS-MLD) can create polymer patterns with accurately controlled film thickness and surface roughness. Conventional AS-MLD relies on self-assembled monolayers (SAMs) to inhibit the deposition at unwanted areas and suffers from low selectivity across different surfaces due to the structural degradation of SAMs when exposed to the thermal and chemical environment of MLD. Here, we introduce a paste-like resist (PLR) made of a continuous resin particle network and silicone oil to improve the selectivity of AS-MLD. On a prepatterned Cu/Si substrate, the selectivity of this PLR-based AS-MLD reaches >99.9% after 200 cycles of polyimide deposition, while that for the SAMs-based AS-MLD is near zero. The PLR fully preserves its structure during the MLD process, is completely removable after the MLD process, and has no adverse effects on the physicochemical properties of the polyimide film. The PLR-based AS-MLD applies to various polymers (e.g., polyurea and alucone) and is compatible with different metal/Si substrates (e.g., Cu/Si and Au/Si).