A metal circuit structure is provided. The metal circuit structure includes a substrate, a first trigger layer and a first metal circuit layer. The first trigger layer is disposed on the substrate and includes a first metal circuit pattern. The first metal circuit layer is disposed on the first circuit pattern and is electrically insulated from the substrate. The composition of the first trigger layer includes an insulating gel and a plurality of trigger particles. The trigger particles are at least one of organometallic particles, a chelation and a semiconductor material having an energy gap greater than or equal to 3 eV. The trigger particles are disposed in the insulating gel, such that the dielectric constant of the first trigger layer after curing is between 2 and 6.5.