Nanoscale-Dewetting-Based Direct Interconnection of Microelectronics for a Deterministic Assembly of Transfer Printing.

As electronics dramatically advance, their components should be fabricated for miniaturized scale, and integrated on limited-size substrates with extremely high density. Current technologies for the integration and interconnection of electronics show some critical limitations in the application of microscale electronics. To address these problems, herein, a new direct and vertical interconnection driven by selective dewetting of a polymer adhesive is introduced. The interconnection system consists of the polymer adhesive and nanosized metal particles, or structured electrodes. Nanoscale-dewetting windows formed by controlling the stability and wetting property of the adhesive polymer are controlled by the interfacial property of the coated polymer adhesive. The adhesive is coated on substrate by a simple spin-coating process, and its ultraviolet curable property allows only the device-mounted parts to be selectively conductive and sticky, while the other parts form insulation and protection layers. The interconnection of the electronics and substrate by adhesive makes it possible to apply the technique to various microsize electronics with electrode size and pitch of 20 µm or less, and endure dramatic temperature change and a long-term high humidity environment. Moreover, over display comprising over 10 000 microscale light-emitting diodes (micro-LEDs), and commercialized microchips are demonstrated with monolithic integration on flexible and transparent substrate.