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|Title:||Multi-foci laser separation of sapphire wafers with partial thickness scanning||Authors:||Lye, Celescia Siew Mun
Lam, Yee Cheong
|Keywords:||Engineering::Mechanical engineering||Issue Date:||2022||Source:||Lye, C. S. M., Wang, Z. & Lam, Y. C. (2022). Multi-foci laser separation of sapphire wafers with partial thickness scanning. Micromachines, 13(4), 506-. https://dx.doi.org/10.3390/mi13040506||Project:||U12-M-007JL||Journal:||Micromachines||Abstract:||With multi-foci laser cutting technology for sapphire wafer separation, the entire cross-section is generally scanned with single or multiple passes. This investigation proposes a new separation technique through partial thickness scanning. The energy effectivity and efficiency of the picosecond laser were enhanced through a two-zone partial thickness scanning by exploiting the internal reflection at the rough exit surface. Each zone spanned only one-third thickness of the cross-section, and only two out of three zones were scanned consecutively. A laser beam of 0.57 W and 50 kHz pulse repetition rate was split into 9 foci, each with a 2.20 μm calculated focused spot diameter. By only scanning the top two-thirds sample thickness, first its middle section then upper section, a cleavable sample could result. This was achieved with the lowest energy deposition at the fastest scanning speed of 10 mm/s investigated. Although with partial thickness scanning only, counter intuitively, the cleaved sample had a previously unattained uniform roughened sidewall profile over the entire thickness. This is a desirable outcome in LED manufacturing. As such, this proposed scheme could attain a cleavable sample with the desired uniformly roughened sidewall profile with less energy usage and faster scanning speed.||URI:||https://hdl.handle.net/10356/160544||ISSN:||2072-666X||DOI:||10.3390/mi13040506||Schools:||School of Mechanical and Aerospace Engineering||Organisations:||Singapore Institute of Manufacturing Technology (SIMTech), A*STAR
Genuine Solutions Pte Ltd.
|Research Centres:||SIMTech-NTU Joint Laboratory (Precision Machining)||Rights:||© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).||Fulltext Permission:||open||Fulltext Availability:||With Fulltext|
|Appears in Collections:||MAE Journal Articles|
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