| ZHANG Wei,LIU Tao,HE Jia-le,ZHANG Jia-fa,ZHANG Yu-liang,LONG Jiang-you,XIE Xiao-zhu.Full Dicing of Ultra-thin Silicon Carbide Substrate by Femtosecond Laser[J],52(1):306-313 |
| Full Dicing of Ultra-thin Silicon Carbide Substrate by Femtosecond Laser |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.01.031 |
| KeyWord:laser dicing ultra-thin silicon carbide infrared femtosecond laser section morphology surface roughness test bending strength test |
| Author | Institution |
| ZHANG Wei |
Laser Micro/Nano Processing Lab,Guangzhou , china |
| LIU Tao |
Laser Micro/Nano Processing Lab,Guangzhou , china |
| HE Jia-le |
Laser Micro/Nano Processing Lab,Guangzhou , china |
| ZHANG Jia-fa |
Laser Micro/Nano Processing Lab,Guangzhou , china |
| ZHANG Yu-liang |
Laser Micro/Nano Processing Lab,Guangzhou , china |
| LONG Jiang-you |
Laser Micro/Nano Processing Lab,Guangzhou , china ;State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment,Guangzhou , china |
| XIE Xiao-zhu |
Laser Micro/Nano Processing Lab,Guangzhou , china ;State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment,Guangzhou , china ;Department of Experiment Teaching, School of Electromechanial Engineering,Guangdong University of Technology, Guangzhou , china |
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| Abstract: |
| To achieve full dicing of ultra-thin silicon carbide substrate in this paper, it is necessary to attain a narrow grooves (<25 μm) with high quality while ensuring bending strength of substrate after dicing. The silicon carbide substrate was full diced by femtosecond laser with the wavelength of 1 030 nm. The effects of pulse repetition rate, pulse energy, dicing speed and scanning times on the groove width, groove depth and section morphology were analyzed by scanning electron microscope and optical microscopy. The microelement analysis of the section surface under different pulse energy was carried out by energy dispersive spectrometer, the surface roughness was measured by laser scanning confocal microscope, and the bending strength of substrate were tested by electronic universal testing machine. The results show that there were mainly three elements in the groove section, including Si, C and O. O element is enriched at the edge of the section. The micro/nano structure of the cross section was affected by sputtering and redeposition of SiO2 particle. Different size structure occurred for using diverse pulse energy. The surface roughness of the section increased with the enhancement of pulse energy, whereas the strength decreased according to the three point bend testing. A better groove with the width of 15 μm and depth greater than 100 μm was obtained by pulse energy of 3.08 μJ, pulse repetition rate of 610 kHz, dicing speed of 4 mm/s and scanning times of 12. The surface roughness of section was 296 nm and the bending strength of substrate was 364 MPa. It can be concluded that the width and depth of the cutting groove are related to the process parameters of pulse repetition rate, pulse energy, dicing speed and scanning times. The scanning time plays the most important role in the cutting depth. The main factor which affects the cutting width is the pulse energy, followed by the cutting speed. The distribution of O element indicates that SiO2 is accumulated at the edges of the section. Low pulse energy of laser is conductive to the dicing of substrate, for it can decrease the sputtering and redeposition of SiO2 particle which enables the formation of a large number of the melted block structure and low surface roughness of the section. With the reduction in section roughness which means the less defects such as micro-cracks in the fracture surface, the bending strength augments. Excessive pulse energy will cause over-ablation in the section, and the severe redeposition of SiO2 particles will give rise to the roughness of the section. Using the excellent processing parameters in laser dicing, the silicon carbide substrate can be full diced by femtosecond laser with a 15 μm-wide groove. For the ultra-short laser with low pulse energy and high pulse repetition ratio is used and the phase separation phenomenon of SiC materials under the laser radiation exists, the high quality of ablation section morphology and the excellent bending stress of substrate can be attained. |
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