Super stealth dicing of transparent solids with nanometric precision

TL;DR

This paper introduces 'super stealth dicing', a laser technique that overcomes diffraction limits to achieve nanometric precision and high aspect ratios in cutting transparent solids, validated through simulations.

Contribution

The paper presents a novel laser modification method using back-scattering interference to enable nanometric precision in laser dicing of transparent materials.

Findings

Achieved cutting widths of tens of nanometers.

Realized aspect ratios of 10^3 to 10^4.

Validated broad applicability through numerical simulations.

Abstract

Laser cutting of semiconductor wafers and transparent dielectrics has become a dominant process in manufacturing industries, encompassing a wide range of applications from flat display panels to microelectronic chips. Limited by the diffraction barrier imposed on the beam width and its longitudinal extend of laser focus, a trade-off must be made between cutting accuracy and aspect ratio in conventional laser processing, with accuracy typically approaching a micron and the aspect ratio on the order of $10^2$. Herein, we propose a method to circumvent this limitation. It is based on the laser modification induced by a back-scattering interference crawling mechanism, which creates a positive feedback for homogenizing longitudinal energy deposition and lateral sub-wavelength light confinement during laser-matter interaction. Consequently, cutting width on the scale of tens of nanometers and aspect ratio $10^3 \sim 10^4$ were simultaneously achieved. We refer to this technique as ``super stealth dicing'', which is validated through numerical simulations, ensuring its broad applicability. It can be applied to various transparent functional solids, such as glass, laser crystal, ferroelectric, and semiconductor, and is elevating the precision of future advanced laser dicing, patterning, and drilling into the nanometric era.