Multi-pulse LIBDE of fused silica at different thicknesses of the organic absorber layer

Yunxiang Pan, Martin Ehrhardt, Pierre Lorenz, Bing Han, B. Hopp, C. Vass, Xiaowu Ni, Klaus Zimmer

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Laser-induced etching techniques feature several unique characteristics that enable ultraprecise machining of transparent materials. However, LIBDE (laser-induced back side dry etching) and LIBWE (laser-induced back side wet etching) are preferentially studied due to experimental feasibilities either using a very thin or a bulk absorber at the rear side of the transparent material. This study aims to fill the gap by examining the thickness dependence of the absorbing material. Multi-pulse-LIBDE (MP-LIBDE) of fused silica using different thick photoresist absorber layers (dL = 0.2-11.7 μm) was performed with a KrF excimer laser (λ = 248 nm, tp ≈ 20 ns). The influence of several experimental parameters, such as laser fluence, pulse number, film thickness, on the ablation morphology and the etching rate were investigated. Especially at moderate fluences (F = 0.7-1.5 J/cm2) MP-LIBDE and LIBWE show several similar process characteristics such as the etching rate dependence on the laser fluence and the pulse number with a typical etching rate of approx. 12 nm at 1 J/cm2. However, the specific etching rate values depend on the absorber layer thickness, for instance. The morphology of the etched surface is smooth with a roughness of below 5 nm rms. Further, the modification of the surface has been observed and will be discussed in relation to the multi-pulse laser etching mechanism.

Original languageEnglish
Pages (from-to)449-454
Number of pages6
JournalApplied Surface Science
Volume359
DOIs
Publication statusPublished - Dec 30 2015

Fingerprint

Dry etching
Fused silica
Etching
Laser pulses
Lasers
Wet etching
Excimer lasers
Photoresists
Ablation
Film thickness
Machining
Surface roughness

Keywords

  • Confinement
  • Laser
  • Laser ablation
  • Laser etching
  • LIBDE
  • Photoresist

ASJC Scopus subject areas

  • Surfaces, Coatings and Films

Cite this

Multi-pulse LIBDE of fused silica at different thicknesses of the organic absorber layer. / Pan, Yunxiang; Ehrhardt, Martin; Lorenz, Pierre; Han, Bing; Hopp, B.; Vass, C.; Ni, Xiaowu; Zimmer, Klaus.

In: Applied Surface Science, Vol. 359, 30.12.2015, p. 449-454.

Research output: Contribution to journalArticle

Pan, Yunxiang ; Ehrhardt, Martin ; Lorenz, Pierre ; Han, Bing ; Hopp, B. ; Vass, C. ; Ni, Xiaowu ; Zimmer, Klaus. / Multi-pulse LIBDE of fused silica at different thicknesses of the organic absorber layer. In: Applied Surface Science. 2015 ; Vol. 359. pp. 449-454.
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