Micro-groove manufacturing via a femtosecond laser on optically clear adhesive films

Abstract

In this study, the femtosecond laser ablation of optically clear adhesives (OCAs) was carried out to machine a smooth groove for optoelectronic module and chip integrated manufacturing. A series of microstructures (holes, channels and grooves) were machined and investigated with different incident laser energies. To design an appropriate array period and inverted trapezoidal shape for the channels, a smooth groove with average roughness 5.7μm was machined. After processing, a new method with visual detection was introduced to evaluate the tack of micro-areas. The results illustrate that both the tack and transmittance of the films are decreased after laser irradiation. With quantitative analysis of FTIR spectra, a massive loss of chemical bonds (hydrogen radicals) leads to performance degradation at the macro level. The partial preservation of the C-O,C=O and -OH bond maintains the stability of the irradiated structure with a small tack and transmittance.