Work

High-quality multi-focus laser stealth dicing of silicon wafer via precise control of spatial focus and laser energy

Year: 2026

Type: article

Abstract: Precise cutting of silicon (Si) wafers is of importance for the micro-chips' performance. Traditional diamond blade dicing induces contact stress, causing micro-cracks that hinder high-integrity dicing. Laser stealth dicing (LSD) offers narrow kerf and minimal thermal damage, making it widely used in Si wafer processing. However, current LSD relies on single-focus layer-by-layer scanning, resulting in low efficiency and poor cut-surface quality. Therefore, this study proposed what is to the best of our knowledge a new multi-focus LSD (MF-LSD) method based on liquid crystal on silicon spatial light modulator (LCOS-SLM), combined with an image feedback-based Gerchberg-Saxton-weighted (IGSW) algorithm, to explore influences of spatial focus and laser energy on LSD of Si wafers. Results showed that precise control of focal positions achieved a flat, continuous cut surface when focal spacing was optimized to 8 μm. By optimizing energy distribution, the crack path deviation was reduced by 50% (maximum ±1 μm), while the calculated processing efficiency reached 2.64 times that of single-focus LSD (for a 6-inch wafer with a die size of 2 × 2 mm). This study provided technical support and theoretical guidance for high-quality MF-LSD of Si wafers.

Source: Optics Express

DOI: 10.1364/oe.617880

Authors: Luo Zhang, Bin Liu, Qinghua Lv, Zili Lei, Chenwei Zhu, Zhongsheng Zhai

Institution: Hubei University of Technology

Language: English

Topic: Laser Material Processing Techniques

Subfield: Industrial and Manufacturing Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,270

Funders: National Natural Science Foundation of China, Science and Technology Department of Hubei Province