Glass cutting using ultrashort pulsed bessel beams

Glass cutting is a subject of high interest in flat panel display and smart-electronics industries. The key issue is to combine high throughput, low residual thermal load and good sidewall quality. The process must be energy-efficient and material-efficient as well. Among laser-based and diamond tool-based existing solutions, ultrashort pulses (USP) appears as a promising technology. Indeed, USP enables to produce internal modification owing to non linear absorption. Under specific irradiation conditions, this internal modification can lead to a free separation of the two glass parts.

In this paper we report on recent investigations dealing with soda lime glass and Sapphire cutting using an USP Bessel beam. In fact, the long and uniform spot of zero-order non-diffractive Bessel beam can be turned into advantage in order to produce an elongated modification along the glass thickness (more than 1 mm long), and to achieve stealth dicing or controlled fracture propagation. The influence of pulse duration, pulse energy, and repetition rate will be discussed in terms of cutting feasibility, extend of heat affected zone and sidewall morphology. The results will be compared to those obtained with Gaussian beams under elongated-spot focusing conditions.