| Project/Area Number |
23KJ0553
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| Research Category |
Grant-in-Aid for JSPS Fellows
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| Allocation Type | Multi-year Fund |
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| Section | 国内 |
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| Review Section |
Basic Section 18020:Manufacturing and production engineering-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
REN GUOQI 東京大学, 工学系研究科, 特別研究員(PD)
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| Project Period (FY) |
2023-04-25 – 2025-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2024: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2023: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | レーザ開発 / レーザ加工 / 微細加工 |
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| Outline of Research at the Start |
本研究は半導体材料への高能率，微細，精密レーザ加工技術を確立する．初めに，超短パルスレーザとマイクロ秒レーザを同時に発振できる超精密同期ファイバーレーザシステムを開発し，半導体の瞬時物性制御を実現する．次に，半導体内部における電子密度の高速超精密計測技術を開発することで，電子励起状態の定量的な計測を実現する．最後に，電子励起状態の計測・物性制御技術を統合し，半導体への過渡選択的レーザ加工法を実現する．
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| Outline of Annual Research Achievements |
The aim of this research is to achieve the precision ultrafast micro processing of semiconductors by inventing a new laser system and controlling the dynamic of excited electrons.
The first step is to develop a novel laser system with a wavelength of 1550 nm. In last year, A narrowband erbium-doped fiber laser oscillator (EDFL) was developed. The mode locked EDFL has an average power of 7.2 mW, a pulse duration of 12 ps at a repetition rate of 50.47 MHz. The spectral bandwidth is 0.37 nm, making it a suitable seeder for the development of a high-average-power master oscillator power amplifier (MOPA) fiber laser system taking advantage of the high SPM during amplification to obtain a broad spectrum and yield sub-ps pulses with a clean temporal profile after pulse compression beyond the power amplifier. Furthermore, a quasi-continuous-wave laser was developed to test the amplification. The output power was 38.24 W with a root mean square instability of 0.19% providing an excellent performance under environmental perturbations. Moreover, the laser had a tunable pulse duration from 2 to 5 μs and a constant pulse energy of 190 μJ.
Besides, through investigating the ultrafast dynamic of ultrafast laser-matter interactions, a new processing method was proposed and experimentally demonstrated in transparent dielectrics, which is expected to be used for other materials.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
This research was well conducted as planned in last year. There are mainly two aspects in my research works.
(1) Laser development for novel processing applications: A 200 kHz master oscillator power amplifier erbium-ytterbium-doped fiber laser system was developed. It has a wavelength of 1548.7 nm with a constant pulse energy of 190 μJ providing a tunable pulse duration of 2 to 5 μs. The all-fiber laser system consists of a gain-modulated laser diode used as a seeder, two pre-amplifiers, and a booster amplifier. The output power of the laser system after collimation was 38.24 W, with a root mean square instability of 0.19% providing an excellent performance under environmental perturbations. After synchronization to femtosecond pulses, the obtained μs laser pulses are expected to contribute to novel microprocessing of semiconductors. Besides, a narrowband erbium-doped fiber laser oscillator (EDFL) was developed. The mode locked EDFL has an average power of 7.2 mW, a pulse duration of 12 ps at a repetition rate of 50.47 MHz. The narrow spectral bandwidth of 0.37 nm makes it a suitable seeder for the development of a high-average-power master oscillator power amplifier (MOPA) fiber laser system.
(2) Laser processing: I investigated the ultrafast dynamics of laser-matter interactions, and then proposed a novel method for precision microprocessing without cracks. By using this method, the drilling depth increases more than 3.3 times, and the aspect ratio is improved at least 2.2 times.
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| Strategy for Future Research Activity |
In this year, the research will be conducted from the following aspects.
(1) Laser development: To continue developing the novel laser system. The main work is to amplify the power of the ultrafast laser by using a pre-amplifier and a main amplifier. After the amplification, a Treacy compressor consisting of two transmission gratings is needed to compress the laser pulse to get pulses with a duration of 1 picosecond or even femtosecond.
(2) Laser processing: To precisely measure the electron density in the plasma filament generated by an ultrafast laser pulse, which is of significance for the transient and selective laser processing.
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