# Damage‐Free Full‐Thickness Dicing of Ultra‐Thin GaAs Wafers Using a Femtosecond Laser with Low Residual Stress

## TL;DR

A new laser method is introduced to cut ultra-thin gallium arsenide wafers without causing damage or stress, improving manufacturing efficiency.

## Contribution

A femtosecond laser with a Bessel beam is used to dice GaAs wafers with minimal thermal damage and residual stress.

## Key findings

- The method achieves an average sidewall roughness of 1.205 µm for 112 µm-thick GaAs wafers.
- The dicing process induces low residual stress of 0.461 GPa.
- The method suppresses melting and minimizes the heat-affected zone.

## Abstract

Gallium arsenide (GaAs) is a widely used semiconductor material due to its low‐temperature coefficient and high absorption efficiency. However, its hardness and brittleness create challenges in wafer‐level packaging, especially for large‐size and ultra‐thin GaAs wafers. These challenges include chipping and the formation of a wide heat‐affected zone (HAZ), both of which reduce production yield. Here, a dicing method is proposed that utilizes a non‐diffracting Bessel beam to shape the femtosecond laser, enabling high‐speed, high‐precision, and high‐aspect‐ratio dicing of brittle GaAs wafers while avoiding the thermal damage and debris issues inherent in conventional methods. An average sidewall roughness (Sa) of 1.205 µm is achieved when cutting a 112 µm‐thick GaAs wafer. In addition, the dicing process induces low residual stress, measured at 0.461 GPa. These results demonstrate that the proposed method is effective for cutting large, ultrathin, hard, and brittle GaAs wafers. It can help improve yield and reliability in integrated circuit (IC) chip production.

This study presents a femtosecond laser‐based ultrashort pulse dicing system that uses a non‐diffracting Bessel beam to shape the femtosecond laser. The use of femtosecond Bessel beam shaping and high‐speed scanning enables rapid material removal that outpaces thermal diffusion, thereby suppressing melting, minimizing the HAZ, and reducing sidewall roughness.