FB2B laser ablation of UV transparent polymer material

Abstract

Precise microfabrication of amorphous fluoric-polymer (CYTOP), which is highly transparent in the wavelength range from 200 nm to 2 μm has been demonstrated by FB2B laser (λ > 157 nm). FB2B laser ablation achieves well-defined micro-patterning with little thermal effect and little debris deposition at etched area. The etching rate linearly increases with number of pulses and logarithm of laser fluence. The FB2B laser ablation of CYTOP proceeds by single-photon absorption and its effective absorption coefficient is approximately ~10.5 P cm.. -1 P. On the other hand, KrF (λ=248 nm), ArF (λ=193 nm) excimer laser, and femtosecond laser (λ=775 nm, τ=180 fs) can not perform highquality ablation due to excellent transparency of CYTOP. Etched area ablated by FB2B laser shows no visible change, while the other lasers induce color change to black. It is deduced that the color change is responsible for carbonization due to thermal effect induced by multiphoton absorption.