Numerical modeling of ultrashort-pulse laser ablation of silicon

Korfiatis, D. P.; Thoma, Klaus; Vardaxoglou, J.C.

doi:10.1016/j.apsusc.2009.04.036

Cited by 25 publications

(10 citation statements)

References 30 publications

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“…3(d)]. The variation tendency of the ablation depth is consistent with previous theoretical and experimental results [25]. To numerically represent the aforementioned ellipticity of the crater, we also define a parameter K as the aspect ratio of a to b, where a and b are the lengths of the major axis and the minor axis, respectively.…”

Section: Resultssupporting

confidence: 84%

Polarization-dependent elliptical crater morphologies formed on a silicon surface by single-shot femtosecond laser ablation

Jiang

et al. 2014

Appl. Opt.

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Formation of the elliptical-shaped craters on a silicon surface is investigated comprehensively using a single shot of a femtosecond laser. It is observed that the ablation craters are elongated along the major axis of the polarization direction, while their orientation is parallel to the polarization direction. The ablation area grows and the morphology of the craters evolves from an ellipse to nearly a circle with increasing fluence. The underlying physical mechanism is revealed through numerical simulations that are based on the finite-difference time-domain technique. It is suggested that the initially formed craters or surface defects lead to the redistribution of the electric field on the silicon surface, which plays a crucial role in the creation of the elliptical-shaped craters. In addition, the field intensity becomes enhanced along the incident laser polarization direction, which determines the elliptical crater orientations.

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Section: Resultssupporting

confidence: 84%

Polarization-dependent elliptical crater morphologies formed on a silicon surface by single-shot femtosecond laser ablation

Jiang

et al. 2014

Appl. Opt.

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“…As seen in the Figure 1, the fluence of 1.5J/cm 2 is estimated to be the threshold value. Table 2 The material parameters and the simulation conditions for the finite element model [13][14][15] Laser spot diameter 15 µm Boiling temperature 3270 o C Heat of vaporization 12.507 MJ/kg Melting temperature 1410 o C Thermal conductivity and specific heat temperature dependent ( Fig. 2(a), Fig.…”

Section: Ablation Threshold Fluence Of Siliconmentioning

confidence: 99%

Analysis of silicon via hole drilling for wafer level chip stacking by UV laser

Lee

Choi

2010

Int. J. Precis. Eng. Manuf.

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For stacking wafers/dies, through-silicon-vias (TSVs) need to be created for electrical connection of each wafer/die, which enables better electrical characteristics and less footprints. And for via hole processing, chemical methods such as DRIE (Deep Reactive Ion Etching) are mostly used. These methods suffer the problems of slow processing speed, being environment-unfriendly and damage on the existing electric circuits due to high process temperature. Furthermore, masks are also needed. To find an alternative to the methods, researches on the laser drilling of via holes on silicon wafer are being conducted. This paper investigates the silicon via hole drilling process using laser beam. The percussion drilling method is used for this investigation. It is also examined how the laser parameters-laser power, pulse frequency, the number of laser pulses and the diameter of laser beam-have an influence on the drilling depth, the hole diameter and the quality of via holes. From these results, laser drilling process is optimized. The via hole made by UV laser on the crystal silicon wafer is 100µm deep, has the diameter of 27.2µm on the top, 12.9µm at the bottom. These diameters deviate from the target values by 2.8µm and 0.4µm respectively. These values correspond to the deviation from the target taper angle of the via hole by less than 1°. The processing speed of the laser via hole drilling is 114mm/sec, therefore, etching process can be replaced by this method, if the number of via holes on a wafer is smaller than 470,588. The ablation threshold fluence of silicon is also determined by a FEM model and is verified by experiment.

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“…Our other group of models deals with the overall effect of laser processing, and ignores nearly all micro-level and other factors, e.g. the shape of the laser beam or structure of the sample when made from inhomogeneous material [18], [19], [20], [23], [21], [22].…”

Section: Basic Theory For Modelling Of Laser Ablationmentioning

confidence: 99%

“…Material parameters correspond to parameters of M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT polyimide 1 , which is a widely used polymer in electronics technology and serves as the basis of our laserpolymer investigations. Thermal parameters were the following [27]: (21) According to our previous works, 0.132 TEF*CEF factor and 535 ˚C ablation threshold temperature and 1.4 m µ 1 absorption coefficient were chosen for performing the simulation [4]. The initial temperature of the material was 25 ˚C.…”

Section: Modelling Of Laser Ablationmentioning

confidence: 99%

Computer modelling of the laser ablation of polymers

Sinkovics

Gordon

Harsányi

2010

Applied Thermal Engineering

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Laser ablation of polymers has been the subject of extensive studies for nearly three decades. Results of these investigations have shown that thermal effects play an important role during frequency tripled nanosecond Nd:YAG laser ablation of polyimide. Despite of the studies, effect of these processes has not been satisfactorily clarified. Thermal effects, photochemical and other phenomena still exist and so the thermal modelling of laser ablation is a very specialised problem. The investigation in this paper deals with special conditions in thermal models, which highly differ from more common conditions. Although there are numerous excellent thermal modelling software available, mainly in the field of electronics technology, these are not suitable or ready for handling special conditions, for example the removing of material from the domain under investigation, which is one of the most important areas. Hence we decided to develop a special thermal modelling tool. The model designing aspects which define the development process are presented in this paper.

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Numerical modeling of ultrashort-pulse laser ablation of silicon

Cited by 25 publications

References 30 publications

Polarization-dependent elliptical crater morphologies formed on a silicon surface by single-shot femtosecond laser ablation

Polarization-dependent elliptical crater morphologies formed on a silicon surface by single-shot femtosecond laser ablation

Analysis of silicon via hole drilling for wafer level chip stacking by UV laser

Computer modelling of the laser ablation of polymers

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