Laser drilling with a top-hat beam of micro-scale high aspect ratio holes in silicon nitride

Nasrollahi, Vahid; Penchev, Pavel; Batal, Afif; Le, Hoang; Dimov, Stefan Simeonov; Kim, Kyunghan

doi:10.1016/j.jmatprotec.2020.116636

Cited by 21 publications

(8 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The bleaching or removal of near-surface black inclusions in diamonds by injecting strong acids through tiny laser-drilled channels is a common method to increase the quality and clarity of diamonds [ 21 ]. Micro-holes are a functional feature in microelectronics serving as microelectrodes or via connections through printed circuit boards, where a high-aspect ratio is important and a stack of dissimilar layers of material present [ 22 ]. In order to produce solar cells with higher efficiencies, a new design and process chain have been developed utilizing laser drilled through-holes, which are metallically contacted to the backside [ 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Putzer

Ackerl

Wegener

2020

Int J Adv Manuf Technol

View full text Add to dashboard Cite

Ultra-short pulsed laser ablation enables a defined generation of micro-holes. A parameter study on the ablation characteristics of copper clearly reveals a benefit for green wavelength with lower threshold fluence, simultaneously increasing the Rayleigh length. The use of a circular drilling method allows a defined manufacturing of micro boreholes and micro through-holes with 35 μm diameter of up to 165 μm and 300 μm length. Introducing high-resolution micro-computed X-ray tomography studying the micro-hole evolution and adjacent geometrical transformations reveals micrometer resolution and high usability. The conical geometry evolving up to an aspect ratio of 5:1 fits well to established models known for percussion drilling. However, increasing the number of pulses leads to non-conical geometry evolution, and this resulting geometry is studied for the first time. Henceforth, the exact geometrical evolution from conical to cylindrical shape upon laser drilling can be resolved revealing the impact of multiple reflections at the generated steep flanks.

show abstract

Section: Introductionmentioning

confidence: 99%

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Putzer

Ackerl

Wegener

2020

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…The similar hole diameters of the top and bottom side coincide well with the measured small taper angles shown in Figure 10 e. This result regarding small taper angle is very important for application to the SPR for dissimilar CFRP/metal joints. In an effort to reduce the taper angle, precision machining was developed and the effect of the top-hat beam was investigated [ 41 , 42 ]. Those methods might be not suitable for millimeter-scale machining of CFRP materials due to thermal effects and low processing time.…”

Section: Resultsmentioning

confidence: 99%

Green Picosecond Laser Machining of Thermoset and Thermoplastic Carbon Fiber Reinforced Polymers

et al. 2021

View full text Add to dashboard Cite

There has been an increase in demand for the development of lightweight and high-strength materials for applications in the transportation industry. Carbon fiber reinforced polymer (CFRP) is known as one of the most promising materials owing to its high strength-to-weight ratio. To apply CFRP in the automotive industry, various machining technologies have been reported because it is difficult to machine. Among these technologies, picosecond laser beam-induced machining has attracted great interest because it provides negligible heat transfer and can avoid tool wear. In this work, we conducted and compared machining of 2.15 mm-thick thermoset and 1.85 mm-thick thermoplastic CFRPs by using a green picosecond laser. The optimized experimental conditions for drilling with a diameter of 7 mm led to a small taper angle (average ~ 3.5°). The tensile strength of the laser-drilled specimens was evaluated, and the average value was 570 MPa. Our study indicates that green picosecond laser processing should be considered as a promising option for the machining of CFRP with a small taper angle.

show abstract

“…Similarly, as for the production of a top-hat beam, when an Airy pattern is focused through a focusing lens, at positions before the focal plane, an annular intensity distribution can be formed, as illustrated in Fig. 8.2 [54]. Commonly, applications for annular beams can be found in illumination systems, since it is possible to induce changes over a ring-shaped region while keeping the center unaffected.…”

Section: Annular and Vortex Beamsmentioning

confidence: 99%

Probing Light by Matter: Implications of Complex Illumination on Ultrafast Nanostructuring

Florian

Du²,

Arnold³

2023

Springer Series in Optical Sciences

View full text Add to dashboard Cite

Pushing the limits of precision and reproducibility in ultrafast laser-based nanostructuring requires detailed control over the properties of the illumination. Most traditional methods of laser-based manufacturing rely on the simplicity of Gaussian beams for their well-understood propagation behavior and ease of generation. However, a variety of benefits can be obtained by moving beyond Gaussian beams to single or multiple tailored beams working toward optimal spatial and temporal control over the beam profiles. In this chapter, we center our attention on methods to generate and manipulate complex light beams and the resulting material interactions that occur in response to irradiations with these non-traditional sources. We begin with a discussion on the main differences between Gaussian and more complex light profiles, describing the mechanisms of phase and spatial control before narrowing the discussion to approaches for spatial structuring associated with materials processing with ultrashort laser pulses. Such structuring can occur in both far-field propagating architectures, considering rapidly varying spatial profiles generated mechanically or optically, as well as near-field, non-propagating beams associated with plasmonic and dielectric systems. This chapter emphasizes some of the unique abilities of complex light to shape materials at the nanoscale from a fundamental perspective while referencing potential applications of such methods.

show abstract

Laser drilling with a top-hat beam of micro-scale high aspect ratio holes in silicon nitride

Cited by 21 publications

References 40 publications

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Green Picosecond Laser Machining of Thermoset and Thermoplastic Carbon Fiber Reinforced Polymers

Probing Light by Matter: Implications of Complex Illumination on Ultrafast Nanostructuring

Contact Info

Product

Resources

About