Silver pattern transfer technique using concave region of mold and silver ink

In this study, we performed two-tone transfer using silver ink by the nano-transfer printing process, which does not involve a vacuum deposition step. To achieve a two-tone transfer, it is necessary to separate the metal film from the top surface of the mold and the metal part at the bottom of the hole. However, in the case of silver ink, the hole is often completely filled, therefore, separation between the top surface and the bottom of the hole is difficult. We performed spin coating to thin out the silver ink in the mold, confirmed that the silver ink can be separated at the top and bottom of the mold by baking, and investigated the relationship between the number of spin coating revolutions and the pattern success rate. The success rate for scooping the bottom silver from the 2 cm × 2 cm line-and-space mold was ∼85%.