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Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning

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 las...

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Autores principales: Lye, Celescia Siew Mun, Wang, Zhongke, Lam, Yee Cheong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9033070/
https://www.ncbi.nlm.nih.gov/pubmed/35457810
http://dx.doi.org/10.3390/mi13040506
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author Lye, Celescia Siew Mun
Wang, Zhongke
Lam, Yee Cheong
author_facet Lye, Celescia Siew Mun
Wang, Zhongke
Lam, Yee Cheong
author_sort Lye, Celescia Siew Mun
collection PubMed
description 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.
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spelling pubmed-90330702022-04-23 Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning Lye, Celescia Siew Mun Wang, Zhongke Lam, Yee Cheong Micromachines (Basel) Article 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. MDPI 2022-03-24 /pmc/articles/PMC9033070/ /pubmed/35457810 http://dx.doi.org/10.3390/mi13040506 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/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/).
spellingShingle Article
Lye, Celescia Siew Mun
Wang, Zhongke
Lam, Yee Cheong
Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning
title Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning
title_full Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning
title_fullStr Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning
title_full_unstemmed Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning
title_short Multi-Foci Laser Separation of Sapphire Wafers with Partial Thickness Scanning
title_sort multi-foci laser separation of sapphire wafers with partial thickness scanning
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9033070/
https://www.ncbi.nlm.nih.gov/pubmed/35457810
http://dx.doi.org/10.3390/mi13040506
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