Abrupt initiation of material removal by focusing continuous-wave fiber laser on glass

Yoshizaki, Reina; Ito, Yusuke; Miyamoto, Naoyuki; Shibata, Akihiro; Nagasawa, Ikuo; Nagato, Keisuke; Sugita, Naohiko

doi:10.1007/s00339-020-03836-4

Cited by 7 publications

(3 citation statements)

References 23 publications

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“…46 In a later report a 300 W, 1.1 µm fiber laser was utilized to demonstrate the same backside absorber process with topside ejection of material. 47 Yoshizaki et al 48 have, without the assistance of a backside absorber layer, generated a high-aspect ratio hole by focusing a high power CW laser onto glass for tens of milliseconds. This approach relies on the glass heating up sufficiently (calculated to be in the range of 900-1200 °C) to drive linear absorption, which once initiated results in rapid hole formation with linear drill rates of 3-4 m/s.…”

Section: Laser-based Methods For Forming Tgvsmentioning

confidence: 99%

“…74 This incubation period phenomenon for glass is consistent with the observation by Yoshizaki et. al, 48 where the increase in the absorption coefficient above a threshold temperature contributes to the initiation of the glass processing with a CW laser. After the incubation period the glass achieves high enough temperatures that linear abosorption becomes the dominant contributor to the free electron concentration.…”

Section: Dynamics Of Tgv Formation With a Ps-qcw Lasermentioning

confidence: 99%

“…1,17,19,75 Recent reports 6 have demonstrated dramatic improvements in the linear drill speed for TGVs: a hybrid method, employing a combination of ultrafast and CW lasers, had a linear drill speed of ∼3.3 m/s. 55 The single CW laser approach of Yoshizaki et al, 48 demonstrated a 3-4 m/s progression of the molten region during drilling; however, this requires an incubation period up to tens of ms prior to accessing the linear absorption regime. Including the ∼1-10 ms incubation period for the CW process reduces the effective linear drill speed to only ∼0.01-0.1 m/s.…”

Section: A High Throughput Processmentioning

confidence: 99%

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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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Section: Laser-based Methods For Forming Tgvsmentioning

confidence: 99%

Section: Dynamics Of Tgv Formation With a Ps-qcw Lasermentioning

confidence: 99%