Microgroove etching on flexible copper clad laminate with picosecond lasers

Liquid crystal polymers (LCPs) have received extensive attention in the field of 5G electronic device packaging because of their high performance as microwave substrates and packaging materials. This article describes the use of a two-wavelength picosecond laser, with a pulse duration of 8.8 ps and a repetition frequency of 100 kHz, to perform ablation experiments on a flexible LCP copper clad laminate. By fitting the experimental results, the calculated radiation exposure was found to be 3.1 and 4.45 J/cm2 at wavelengths of 1064 and 355 nm, respectively. In addition, it was revealed that the laser parameters and the material characteristics of the LCP seriously affected the quality of laser machining due to photopolymerization of the LCP at 1064 nm; in contrast, better results were obtained at 355 nm. Furthermore, the effect of scanning speed and average power on the microgroove etching process was investigated. Desirable etching results were obtained at a scanning speed of 500–700 mm/s and an average power of 2.5–3.5 W. The results of this study can be useful for the processing of LCP-encapsulated electronic devices.