Dual-beam stealth laser dicing based on electrically tunable lens

In this paper, we present the development of a high-speed dual-beam stealth laser dicing (D-SLD) method for processing semiconductor wafers based on electrically tunable lenses (ETLs). An SLD system utilizes a laser beam to dice a wafer by inducing interior defects without modifying the surface char...

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Bibliographic Details
Published in:Precision engineering 2020-11, Vol.66, p.374-381
Main Authors: Lee, Hiu Hung, Zhao, Erxuan, Chen, Dihan, Zhang, Nan, Chen, Shih-Chi
Format: Article
Language:English
Subjects:
Dual-beam
Electrically tunable lens
Error compensation
Stealth laser dicing
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Summary:In this paper, we present the development of a high-speed dual-beam stealth laser dicing (D-SLD) method for processing semiconductor wafers based on electrically tunable lenses (ETLs). An SLD system utilizes a laser beam to dice a wafer by inducing interior defects without modifying the surface characteristics of a wafer, thereby presenting significant advantages over conventional dicing methods, e.g., blade dicing or laser ablation. Currently, the throughput of SLD is limited by the serial scanning process; in addition, wafer misalignment and the warpage effects together deteriorate the dicing quality and yield and demand high-cost multi-axis precision stages. To address the issue, we parallelize the dicing process by splitting the laser focus into two foci, where the laser intensity at different depths are automatically adjusted to achieve optimal dicing condition. By combining the height sensor and ETLs, each laser focus, i.e., laser scan lines, can be rapidly controlled axially to compensate the wafer curvature and misalignment errors in real time, leading to substantially improved precision (kerf width 
ISSN:0141-6359
1873-2372
DOI:10.1016/j.precisioneng.2020.08.009