New possibilities with femtosecond GHz-burst laser processing

Lopez, John; Niane, Samba; Bonamis, Guillaume; Audouard, Eric; Hönninger, Clemens; Mottay, Eric; Manek-Hönninger, Inka

doi:10.1117/12.2607118

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…Indeed, as B1 and B32 were investigated in non-overlapped fluence ranges (see Figure 8c), the data for t B1 /t B32 were not available. Thus, F and m appear to be crucial parameters for determining the efficiency of the burst mode, in agreement with other reports [17,32].…”

Section: Evolution Of Processing Time With Number Of Pulses Per Burstssupporting

confidence: 92%

Benefits of Femtosecond Laser 40 MHz Burst Mode for Li-Ion Battery Electrode Structuring

Sikora,

Gemini,

Faucon

et al. 2024

Materials

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In Li-ion batteries, ion diffusion kinetics represent a limitation to combine high capacity and a fast charging rate. To bypass this, textured electrodes have been demonstrated to increase the active surface, decrease the material tortuosity and accelerate the electrolyte wetting. Amongst the structuring technologies, ultrashort pulse laser processing may represent the key option enabling, at the same time, high precision, negligible material deterioration and high throughput. Here, we report a study on the structuring of electrodes with both holes and grooves reaching the metallic collector. Electrochemical models emphasize the importance of hole and line dimensions for the performances of the cell. We demonstrate that we can control the hole and line width by adjusting the applied fluence and the repetition rate. In addition, results show that it is possible to drill 65 µm-deep and ~15 µm-wide holes in nearly 100 µs resulting in up to 10,000 holes/s. To further reduce the takt time, bursts of 40 MHz pulses were also investigated. We show that bursts can reduce the takt time by a factor that increases with the average power and the burst length. Moreover, at comparable fluence, we show that bursts can shorten the process more than theoretically expected.

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Section: Evolution Of Processing Time With Number Of Pulses Per Burstssupporting

confidence: 92%

Benefits of Femtosecond Laser 40 MHz Burst Mode for Li-Ion Battery Electrode Structuring

Sikora,

Gemini,

Faucon

et al. 2024

Materials

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“…1 GHz intra-burst pulse repetition frequency with a Gaussian beam. 49,50 This approach allows for tuning the burst envelope as well as burst energy and duration. While the method can produce very high aspect ratio holes in different types of glass (∼30 µm diameter holes with 30:1 aspect ratio in soda lime glass and 70:1 in fused silica 51 ), the process requires tens of bursts to initiate drilling, a low inter-burst pulse repetition frequency to reduce thermal effects and sidewall collapse, and a very long drill time.…”

Section: Laser-based Methods For Forming Tgvsmentioning

confidence: 99%

Rapid and high throughput formation of through glass vias

Schrauben,

Matsumoto,

Lin

et al. 2024

Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XXIX

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Interest in glass for integrated circuit (IC) packaging and interposer applications has accelerated in recent years, due to its favorable mechanical and electrical properties compared to current advanced materials. This report describes our recent results on through glass via (TGV) drilling, utilizing a novel process employing a single laser source with an engineered pulse duration, pulse repetition frequency, and average power to rapidly form TGVs in 50 and 100 µm thick glass. The process forms TGVs with a ∼10 µm diameter with zero taper, smooth sidewalls and minimal splash; the dimensions of these TGVs meet the requirements for next-generation interposers to replace through silicon vias. Unlike Bessel beam based processes, this process is compatible with high bandwidth beam steering technologies (galvanometers and acousto-optic deflectors (AODs)), enabling an industrially viable throughput in high-density drill patterns of more than 10000 vias per second. The formation dynamics of the TGVs are elucidated using multiphase simulations and in-situ spectroscopic methods. Stress mitigation in the fully-formed TGVs is explored through annealing studies; an alternate approach utilizes heating of the glass substrate during the laser processing to minimize stress formation during the drilling process. Both methods are shown to mitigate embedded stress and avoid cracking.

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“…The main interest of GHz bursts is to use individual pulse fluences below the ablation threshold as shown in early work from the Ilday group [4,5], and subsequently confirmed by several other studies [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. In this case, a refined approach of ablation mechanisms is needed, both thermal and non-thermal, to understand the high increase in ablation efficiency.…”

Section: Ghz Laser Ablationmentioning

confidence: 99%

“…GHz laser processing has been shown to offer higher ablation rates than traditional multi-kHz to MHz, continuous or burst laser sources. However, while some references have reported an improvement in the ablation efficiency by an order of magnitude [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], others have shown more modest results [24][25][26][27][28][29][30][31][32]. Despite these numerous studies, a precise understanding of the physical nature of GHz laser ablation has not yet been established.…”

Section: Introductionmentioning

confidence: 99%

High efficiency GHz laser processing with long bursts

Audouard

Mottay

2023

Int. J. Extrem. Manuf.

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Bursts of GHz repetition rate pulses can significantly increase the ablation efficiency of femtosecond laser material processing.. Ablation by GHz repetition rate bursts of femtosecond pulses is a multi-step process, consisting of a first thermal incubation phase, followed by a highly efficient ablation phase. GHz ablation therefore combines thermal and non-thermal ablation mechanisms. With an optimal choice of the burst duration, the ablation efficiency can be highly enhanced. Long bursts, comprising tens to hundreds of pulses, are required to take full advantage of the increase in ablation efficiency.

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New possibilities with femtosecond GHz-burst laser processing

Cited by 5 publications

References 8 publications

Benefits of Femtosecond Laser 40 MHz Burst Mode for Li-Ion Battery Electrode Structuring

Benefits of Femtosecond Laser 40 MHz Burst Mode for Li-Ion Battery Electrode Structuring

Rapid and high throughput formation of through glass vias

High efficiency GHz laser processing with long bursts

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