Laser microvia drilling and ablation of silicon using 355 nm pico and nanosecond pulses

Pantsar, Henrikki; Herfurth, Hans; Heinemann, Stefan; Laakso, Petri; Penttilä, Raimo; Liu, Yi; Newaz, Golam

doi:10.2351/1.5061387

Cited by 10 publications

(6 citation statements)

References 12 publications

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“…Where  is some kind of penetration depth and  th denotes the threshold fluence. In the case of ultra short pulses one observes two different regimes, one for low fluences and one for high fluences 23 , as shown in figure 15 (the figure is reprinted from the website of the NCLA in Ireland 25 ). The logarithmic law (2) can be rewritten as:…”

Section: Ablation Model For Short and Ultra Short Pulsesmentioning

confidence: 99%

Processing of metals and dielectric materials with ps-laserpulses: results, strategies, limitations and needs

et al. 2010

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Ultra short (ps, fs) laser pulses are used, when high requirements concerning accuracy, surface roughness, heat affected zone etc. are demanded for surface structuring. Ps-laser systems that are suited to be operated in industrial environments are of great interest for many practical applications. Here results in the field of 3-d structuring (metals and transparent materials), induced processes and structuring of flexible solar cells will be presented. Beside the pulse duration, which is given by the laser system, the user has a wide variety of optimization parameters such as fluence, repetition rate and wavelength. Based on a simple model it will be shown, that there exist optimum laser parameters to achieve maximum volume ablation rates at a given average power. To take benefit of these optimum parameters and to prevent harmful effects like plasma shielding and surface melting, adapted structuring strategies, depending on the requirements, have to be used. Today's ultra short pulsed systems have average powers from a few W up to a few 10W at high repetition rates. The actual available beam guiding systems are limited and can often not fulfill the requirements needed for high throughput structuring with optimized parameters. Based on the achieved results, the needs for future beam guiding systems will be discussed.

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Section: Ablation Model For Short and Ultra Short Pulsesmentioning

confidence: 99%

Processing of metals and dielectric materials with ps-laserpulses: results, strategies, limitations and needs

et al. 2010

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“…In order to evaluate the efficiency of the drilling process in relation to the energy input, figure 5 depicts the total energy consumption Qtot needed for through hole generation, given by (2) which is the accumulated pulse energy reaching the material surface, including the reflected, absorbed and transmitted ratios of the irradiated laser pulses. As can be seen, the energy input decreases by applying higher PRFs as a result of heat accumulation induced by laser-matter-interaction.…”

Section: Effects Of Parameter Variation On the Total Energy Consumptionmentioning

confidence: 99%

“…For MEMS, silicon is the most widespread and important material beside polymers, specific metals and ceramics. As laser processing of silicon has been widely investigated during the past, it could be shown, that ultrashort pulse laser radiation is well suitable to fabricate complex and precise microstructures [1,2], micro drilling holes [3][4][5][6] or rather interconnection vias [7][8][9]. This resulted from the outstanding properties of the ultrashort pulses regarding their extremely short laser-material-interaction times and therefore low thermal impact to the sample material.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Laser Structuring within a Process Chain - Influence of the Surface Morphology

2019

JLMN

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Laser processing of silicon, as the most important material for microelectromechanical systems (MEMS), is commonly known and accepted as an effective manufacturing method to fabricate complex and precise micro components. Especially for the fabrication of micro hole grids, the recently developed high pulse repetition frequency (PRF) laser micro drilling technology is a valuable alternative to standard processing techniques. This paper discusses laser percussion drilling of silicon using ultrashort laser pulses at high average powers with the aim to drill through a material thickness of 100 µm. The main process influencing parameters, such as PRF and laser fluence were varied in order to identify optimal parameter settings for high quality and high throughput micro hole drilling. Furthermore, the effect of additional laser pulses, irradiated after drilling through, onto the micro hole geometry was examined. It will be shown that with increasing PRF and thus, lower laser fluence as a result of constant average laser power of the used laser system, the drilling time decreases significantly. This might be due to thermal accumulation induced by the applied highlyrepetitive pulses, leading to a higher substrate temperature which, in turn, lowers the energy needed for melting and evaporation. Surprisingly, this effect results in higher quality of the micro hole geometry without considerable debris at both, hole entrance and exit.

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“…The ablated depth was found to decrease with the ablation rate [4]. Some mechanical and thermal damage was found with nanosecond pulses when using Q-switched Nd: YAG laser to drill silicon wafer [5]. High ablation rate with nanosecond pulses was achieved on some metals; but with evidenced thermal damage on the target [6].…”

Section: Introductionmentioning

confidence: 99%

Nanosecond laser pulses for aluminum and copper drilling

Hamoudi¹

2018

IJP

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Nd:YAG laser pulses of 9 nanosecond pulse duration and operating wavelength at 1.06 μm, were utilized to drill high thermal conductivity and high reflectivity aluminum and copper foils. The results showed a dependence of drilled holes characteristics on laser power density and the number of laser pulses used. Drilled depth of 74 ϻm was obtained in aluminum at 11.036×108 W/cm2 of laser power density. Due to its higher melting point, copper required higher laser power density and/or larger number of laser pulses to melt, and a maximum depth of 25 μm was reached at 13.46×108 W/cm2 using single laser pulse.

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Laser microvia drilling and ablation of silicon using 355 nm pico and nanosecond pulses

Cited by 10 publications

References 12 publications

Processing of metals and dielectric materials with ps-laserpulses: results, strategies, limitations and needs

Processing of metals and dielectric materials with ps-laserpulses: results, strategies, limitations and needs

Ultrafast Laser Structuring within a Process Chain - Influence of the Surface Morphology

Nanosecond laser pulses for aluminum and copper drilling

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