Moulded interconnect devices (MIDs) are thermoplastic circuit carriers with a patterned surface metallization which combines mechanical and electrical functionalities on a single device.

Integration of micro metallic structures in polymer devices is a broad multi-disciplinary research field, consisting of various combinations of mechanical, chemical and physical fabrication methods. Some of these combinations have been known for years and have mostly been used for decorative purposes. Other combinations or methods are very new and developing.