Super-stealth dicing of transparent solids with nanometric precision

Laser cutting of semiconductor wafers and transparent dielectrics has become a dominant process in manufacturing industries, encompassing a wide range of applications from display panels to microelectronic chips. Constrained by the diffraction limit of the beam width and the longitudinal extent of the laser focus, a trade-off between the cutting accuracy and the aspect ratio is inherent to conventional laser processing, with the accuracy typically approaching one micrometre and the aspect ratio of the order of 100. Here we propose a method to circumvent this limitation. Our method exploits a mechanism of back-scattering interference crawling in which the incident beam interferes with light that is back-scattered by laser-induced nanoseeds, creating a positive feedback loop. This mechanism ensures both homogenization of longitudinal energy deposition and confinement of lateral subwavelength light during laser–matter interactions. We achieve cutting widths in the range of tens of nanometres with aspect ratios ranging from 1,000 to 10,000. We refer to this technique as ‘super-stealth dicing’ and we validate it through numerical simulations. The technique can be applied to various transparent functional solids, such as glass, laser crystals and ferroelectric and semiconductor materials, thus promising enhanced precision for future advanced laser dicing, patterning and drilling. Super-stealth laser cutting with nanometre precision and aspect ratios of the order of 1,000 is demonstrated. The technique is applicable to a broad variety of transparent solids, including silica, lithium tantalate, lithium niobate, YAG, Ce:YAG, Ti:sapphire and β-Ga2O3.