Submicron structural alteration of polycarbonate surface due to ArF laser irradiation at high doses and the subsequent electro-chemical etching treatment

Excimer lasers at short UV wavelengths create regular surface microstructure on polycarbonate (PC). The effect is strongly dependent on the laser properties such as pulse energy, laser wavelength and energy dose. Among those, the UV dose is dominant. Moreover, the PC microstructure consists of a network of micro cones, whose size and population change drastically at higher UV doses. The surface hardening at lower doses and the laser ablation at higher doses are investigated to explain the phenomenon. The conical microstructure was subsequently treated using an electro-chemical etching process which turns it into an array of micro holes due to the simultaneous chemical etching and electrical breakdown.