Projection ablation of glass-based single and arrayed microstructures using excimer laser (original) (raw)
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Recent developments on microablation of glass materials using excimer lasers
Optics and Lasers in Engineering, 2007
For many years, the development of effective laser machining techniques for making glass-based microcomponents and devices has been a critical factor in the birth of new photonic and biomedical microsystems. In this article, the characteristics and abilities of excimer lasers for micromachining of a wide range of glass materials are reviewed and studied. Following the introduction, the special features of excimer lasers are discussed. The typical micromachining system used for glass materials is presented. Then, the fundamental micromachining parameters and the associated morphologies of machined surfaces are evaluated. The approaches by controlling the ablation rate for making the curve surfaces are specifically formulated. Although a wide range of commercially available glasses is covered in this article, two types of the most widely used glasses, borosilicate glass and fused silica, are thoroughly examined to illustrate the complexity in micromachining the glass materials. The procedures to machine single, arrayed, curved microstructures are described. The utilizations of these procedures for making microneedles, optical waveguides, submicron grating, and microlenses are specifically demonstrated. Finally, recommendations for future efforts are presented. r
Fabrication of high-aspect-ratio microstructures using excimer laser
Optics and Lasers in Engineering, 2004
An excimer laser micromachining system is developed to study the ablation of high-aspectratio microstructures. The study examines the ablation efficiency, specifically, the impact of changing major laser operating parameters on the resulting microstructural shapes and morphology. The study focuses on glass, although results on silicon and aluminum are also included for comparison. In ablating grooved structures, the ablation depth has been observed to be linearly proportional to the operating parameters, such as the pulse number and fluence. The results specifically indicate that ablation at low fluence and high repetition rates tends to form a V-shaped cross-section or profile, while a U-shaped profile can be obtained at high fluence and low repetition rate. The ablation rate or ablated volume has then been quantified based on the ablation depth measured and the ablated profile observed. The threshold fluence has also been obtained by extrapolating experimental data of ablation rate. The extrapolation accuracy has been established by the good agreement between the extrapolated value and the one predicted by Beer's law. Moreover, a one-dimensional analytical solution has been adopted to predict the ablated volume so as to compare with the experimental data. The reasonable agreement between the two indicates that a simple analytical solution can be used for guiding or controlling further laser operations in ablating glass structures. Finally, the experimental results have shown that increasing the repetition rate favors the morphology of ablated surfaces, though the effect of repetition rate on ablation depth is insignificant. r
An increase in interconnection density, a reduction in packaging sizes and the quest for lowcost product development strategy are some of the key challenges facing micro-optoelectronics design and manufacture. The influence of high-density, small-sized products has placed significant constraints on conventional electrical connections prompting various fabrication methods, e.g. photolithography, being introduced to meet these challenges and ameliorate the rapidly changing demand from consumers. While high-power solid state lasers are fundamental to large scale industrial production, excimer laser on the other hand has revolutionised the manufacturing industry with high precision, easy 3D structuring and less stringent production requirements. Micro-structuring using excimer laser, best known as laser ablation, is a non-contact micro- and nano-machining based on the projection of high-energy pulsed UV masked beam on to a material of interest such that pattern(s) on the mask is transferred to the substrate, often at a demagnified dimension with high resolution and precision. The use of mask with desired patterns and beam delivery system makes the fabrication in this case accurate, precise and easily controllable. The first part of this chapter introduces the fundamentals of laser technology and material processing. In the second part, optical interconnects as a solution to ‘bottlenecked’ conventional copper interconnections is introduced with emphasis on excimer laser ablation of polymer waveguides and integrated mirrors. Key research findings in the area of optical circuit boards using other techniques are also briefly covered. Cite : Zakariyah, S.S. (2012). Laser Ablation for Polymer Waveguide Fabrication, Micromachining Techniques for Fabrication of Micro and Nano Structures, Mojtaba Kahrizi (Ed.), ISBN: 978-953-307-906-6, InTech, Available from: http://www.intechopen.com/articles/show/title/laser-ablation-for-polymer-waveguide-fabrication.
Fabrication of High-Aspect-Ratio Microstructures Using Excimer Lasers
An excimer laser micromachining system is developed to study the process in fabricating high-aspect-ratio microstructures. Specifically, the study experimentally examines process efficiency and the impact of changing major laser operating parameters on the resulting microstructural shapes and morphology. The materials considered in the study include glass, silicon, and aluminum. The ablation or micromachining rate has been observed to be strongly dependent on the operating parameters, such as the pulse fluence, number, and repetition rate. The results specifically indicate that ablation at low fluence and high repetition rate tends to form a V-shaped cavity, while a U-shaped cavity can be obtained at high fluence and low repetition rate. Additionally, the present study also indicates that a three-dimensional V-shaped cavity with large vertex angle can be formed by varying the focus depth of excimer laser. Materials of low thermal conductivity and low melting temperature are indeed more applicable to laser ablation.
Micromachining of TiNi shape memory alloy by excimer laser ablation
Device and Process Technologies for MEMS and Microelectronics II, 2001
In this paper we investigate excimer laser micromachining of TiNi shape memory alloy using an image projection system as an alternative to photolithographic patterning. We report on the characteristics of material removal by KrF excimer laser induced ablation at 248 nm and the dependence of material removal rates on laser parameters such as fluence and pulse frequency. Fluences at the workpiece using a 10× projection lens were up to 2.5 J cm -2 with pulse repetition rates up to 100 Hz. Conventional chrome-on-quartz masks were used for pattern transfer. Material removal mechanisms and rates of material removal are compared with those observed during excimer laser micromachining of polymers and ceramics and limitations on achievable lateral and depth resolution explored. Data obtained by a variety of characterisation methods are correlated to assess the effects of laser induced damage.
Laser Ablation for Polymer Waveguide Fabrication
An increase in interconnection density, a reduction in packaging sizes and the quest for low-cost product development strategy are some of the key challenges facing micro-opto-electronics design and manufacture. The influence of high-density, small-sized products has placed significant constraints on conventional electrical connections prompting various fabrication methods, e.g. photolithography, being introduced to meet these challenges and ameliorate the rapidly changing demand from consumers. While high-power solid state lasers are fundamental to large scale industrial production, excimer laser on the other hand has revolutionised the manufacturing industry with high precision, easy 3D structuring and less stringent production requirements. Micro-structuring using excimer laser, best known as laser ablation, is a non-contact micro- and nano-machining based on the projection of high-energy pulsed UV masked beam on to a material of interest such that pattern(s) on the mask is transferred to the substrate, often at a demagnified dimension with high resolution and precision. The use of mask with desired patterns and beam delivery system makes the fabrication in this case accurate, precise and easily controllable. The first part of this chapter introduces the fundamentals of laser technology and material processing. In the second part, optical interconnects as a solution to ‘bottlenecked’ conventional copper interconnections is introduced with emphasis on excimer laser ablation of polymer waveguides and integrated mirrors. Key research findings in the area of optical circuit boards using other techniques are also briefly covered.
Ablation of Transparent Materials Using Excimer Lasers for Photonic Applications
Optical Review, 2005
For many years, the development of effective ablation or laser machining techniques for making micro-optical components has been the key factor in the birth of new photonic devices and systems. In this article, the ablation characteristics of two types of the most important transparent materials, transparent polymers and glasses, are studied. Simple shaped microcavities are first machined for studying the fundamental ablation parameters, including threshold fluence, effective absorption coefficient, and ablation rate. In studying polymer ablation, five standard grades and five proprietary polymeric compounds are selected. Ablation techniques using these transparent polymers for making arrayed ferrules and curved microlenses are presented. Applications of these ablated microstructures for optical fiber connectors, optical fiber coupling and alignment, and transparent chip encapsulants, are introduced and demonstrated with emphasis on the quality of the ablated profiles and dimensions to satisfy the required performance. In glass ablation, borosilicate glasses are considered and their associated ablation behaviors are studied. The procedures to ablate glass-based arrayed microstructures with flat and curved surfaces are described. The utilizations of these arrayed microstructures for optical waveguide, wave absorber, and beam guider, are specifically discussed. Finally, concluding remakes for future trends are presented. #
SPIE Proceedings, 2000
Laser ablation is extremely well suited for rapid prototyping and proves to be a versatile technique delivering high accuracy dimensioning and repeatability of features in a wide diversity of materials. In this paper, we present laser ablation as a fabrication method for micro machining of arrays consisting of precisely dimensioned U-grooves in dedicated polycarbonate and polymethylmetacrylate plates. The dependency of the performance on various parameters (wavelength, energy density and pulse frequency) is discussed. The fabricated plates are used to hold optical fibres by means of a UVcurable adhesive. Stacking and glueing of the plates allows the assembly of a 2D connector of plastic optical fibres for short distance optical interconnects.
Integrated Optics: Theory and Applications, 2005
A qualitative comparison is made between laser direct writing and laser ablation as enabling technologies for the structuring of multimode waveguides (50x50µm 2 ) and 45º micro-mirrors into an optical layer. A small demonstrator is fabricated that allows us to couple light vertically from a transmitter into an optical layer and from the optical layer to a receiver. The optical layer, a multifunctional acrylate-based photo-polymer, is applied on an FR4-substrate. Multimode waveguides, that carry signals in the plane of the optical layer, are fabricated by means of laser direct writing, a technology that is available at HWU. The 45° micro-mirrors, that provide out-of-plane coupling, are ablated with the laser ablation set-up available at UGent. This set-up contains a KrF-excimer laser (248nm) that can be tilted, which eases the definition of angled facets. Surface roughness measurements are performed on both the optical layer and the micro-mirrors with a non-contact optical profiler. Loss measurements are performed on both the waveguides and the micro-mirrors.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2021
Microcraters on the silicon surface were fabricated with the help of a nanosecond pulsed laser. The features of microcraters fabricated with single laser pulse and pulse trains of various laser intensities were analyzed. In case of single pulse, the diameter and depth of micro-crater rise with the laser fluence and achieve saturation at higher laser intensities. For the range of fluence 62-122 J/cm 2 , the mass of ablated material was in the range of 0.27 × 10 − 9-2.69 × 10 − 9 g/pulse. Numerically simulated temperature trends were compared with the measured crater depths. The influence of laser intensity on the target temperature and onset time to melt/boil were also investigated. In case of pulse trains, the reduction in material removal efficiency is attributed to the plume shielding and accumulation of ablated material on the crater walls. We demonstrated that the laser intensity and number of laser pulses can be used to control the morphology of a microcrater.