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实验装置如图 1所示。激光系统采用型号为ML-MU-W20H的红外光纤激光器,波长为1064nm,最大输出功率为20W,脉宽为100ns,光斑直径为30μm,重复频率为20kHz~200kHz,扫描速率为1mm/s~1000mm/s。为了避免在激光作用下蓝宝石背面与接触材料发生作用,影响刻蚀效果,所以将蓝宝石试样呈悬空放置。实验材料选用c-0001面且双面抛光的蓝宝石基片,其尺寸为14mm×1mm(直径厚度)。金属氧化物分别为TiO2,ZrO2,CuO,ZnO,Cr2O3以及Fe2O3,纯度达到98%,颗粒直径约为1μm~3μm,其熔沸点如表 1所示。实验前需要对蓝宝石基片进行预处理,将蓝宝石基片分别放入去离子水和无水乙醇中超声波清洗5min,然后低温烘干。
Table 1. Melting and boiling points of six metal oxides
TiO2 ZrO2 ZnO CuO Fe2O3 Cr2O3 melting point/℃ 1830 2680 1975 1026 1565 2266 boiling point/℃ 2900 4300 2360 — — 4000 -
先配置金属氧化物涂层,其中骨料约为48%,水性粘结剂聚酰胺-酰亚胺约为19%,稀释剂为水,将涂层均匀涂抹在蓝宝石表面上,然后将涂层烘干,测得涂层厚度约为0.3mm。激光参量为:重复频率20kHz,扫描速率5mm/s,直线扫描1次,离焦量0mm。图 2为金属氧化物涂层辅助激光刻蚀蓝宝石的原理示意图。为了便于计算刻蚀率,将刻槽剖面简化为三角形,则刻蚀率为剖面积与扫描速度的乘积。
异种金属氧化物辅助激光刻蚀蓝宝石的研究
Study on laser etching of sapphire assisted by dissimilar metal oxides
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摘要: 为了提高蓝宝石对普通红外激光的吸收效率, 采用金属氧化物涂层辅助1064nm红外光纤激光器刻蚀蓝宝石。通过单因素研究方法, 研究了不同金属氧化物涂层的刻槽阈值以及激光能量和金属氧化物涂层对刻蚀率的影响, 对6种金属氧化物涂层辅助激光刻蚀的差异以及刻蚀机理进行了理论分析和实验验证。结果表明, TiO2涂层的刻槽阈值最低约为8.5J/cm2、激光能量为77.7J/cm2时, TiO2涂层的刻蚀率最高约为107.3×104μm3/s; 刻蚀率随着激光能量的增大先增大后趋于平缓且有所降低; 刻槽阈值和刻蚀率主要与涂层吸收激光能力、热导率以及熔沸点有关, 其中受涂层吸收激光能力和熔沸点的影响较大。此研究结果对激光加工蓝宝石的工业应用提供一定的技术基础。Abstract: In order to improve the absorption efficiency of sapphire for ordinary infrared lasers, a metal oxide coating was used to assist 1064nm infrared fiber laser to etch sapphire. Through the single factor research method, the groove threshold of different metal oxide coatings and the influence of laser energy and metal oxide coating on the etching rate were studied. The theoretical analysis and experimental verification of the different reasons and mechanisms of the six metal oxide coatings assisted laser etching were carried out. The results show that the minimum groove threshold of TiO2 coating is about 8.5J/cm2, and the highest etching rate of TiO2 coating is about 107.3×104μm3/s when the laser energy is 77.7J/cm2; the etching rate first increases with the increase of laser energy and then tends to be gentle and decreases. The groove threshold and the etching rate are mainly related to the laser absorption ability, thermal conductivity and melting boiling point of the coating, and the laser absorption ability and melting boiling point of the coating are more affected. This research result provides a certain technical basis for the industrial application of laser processing sapphire.
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Key words:
- laser technique /
- laser etching /
- metal oxide coating /
- sapphire
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Table 1. Melting and boiling points of six metal oxides
TiO2 ZrO2 ZnO CuO Fe2O3 Cr2O3 melting point/℃ 1830 2680 1975 1026 1565 2266 boiling point/℃ 2900 4300 2360 — — 4000 -
[1] KE R, ZHANG Y M, HAN J C, et al. Effect of temperature on the transmittance property of patterned sapphire [J]. Journal of Synthetic Crystals, 2014, 43(2): 263-268(in Chinese). [2] SYLVIA H, SEBASTIAN W, ARNE K, et al. Status and prospects of AlN templates on sapphire for ultraviolet light-emitting diodes[J]. Physical Status Solidi, 2020, A217(14): 1901022. [3] NIE H, LU B Zh. Sapphire window and itś application in military electro-optical equipment[J]. Ship Electronic Engineering, 2005, 25(2): 131-133(in Chinese). [4] ZHU C, GERALD R E, HUANG J. Progress toward sapphire optical fiber sensors for high-temperature applications[J]. IEEE Transactions on Instrumentation and Measurement, 2020, 69(11): 8639-8655. doi: 10.1109/TIM.2020.3024462 [5] XU L, LIU Y B, XU Q. Diamond tools for processing crystal silicon and sapphire[J]. Superhard Materials Engineering, 2018, 30(6): 47-51(in Chinese). [6] LAI W H, HUANG Sh W, CHEN Y H, et al. Formation mechanism of self-formed triangular pyramidal patterns on sapphire substrate[J]. Crystal Growth & Design, 2020, 20(7): 4811-4817. [7] YUMOTO J, KUWATA-GONOKAMI M, GILLNER A. Effect of damage incubation in the laser grooving of sapphire[J]. Journal of Applied Physics, 2019, 125(17): 173109. doi: 10.1063/1.5091951 [8] WANG J, TAO Q, HU Ch, et al. Fabrication of sapphire rib waveguides using a femtosecond laser[J]. Optoelectronics Letters, 2019, 15(3): 190-194. doi: 10.1007/s11801-019-8180-8 [9] BAI F, DAI Y T, XU G, et al. Micromachining technology of sa-pphire substrate based on 157nm DUV laser[J]. Laser Technology, 2010, 34(5): 636-639(in Chinese). [10] LU X Z, JIANG F, LEI T P, et al. Laser-induced-plasma-assisted ablation and metallization on c-plane single crystal sapphire (c-Al2O3)[J]. Micromachines, 2017, 8(10): 300. doi: 10.3390/mi8100300 [11] LIU H G, LI Y, LIN W X, et al. High-aspect-ratio crack-free microstructures fabrication on sapphire by femtosecond laser ablation[J]. Optics and Laser Technology, 2020, 132: 106472. doi: 10.1016/j.optlastec.2020.106472 [12] XIE X Zh, ZHOU C X, GAO X Y, et al. Study on working solution of laser-induced backside wet etching [J]. Laser Technology, 2020, 44(1): 7-13(in Chinese). [13] LONG J Y, ZHOU C X, XIE X Zh, et al. Incubation effect during laser-induced backside wet etching of sapphire using high-repetition-rate near-infrared nanosecond lasers[J]. Optics and Laser Technology, 2019, 109: 61-70. doi: 10.1016/j.optlastec.2018.07.066 [14] CAPUANO L, TIGGELAAR R M, BERENSCHOT J W, et al. Fabrication of millimeter-long structures in sapphire using femtosecond infrared laser pulses and selective etching[J]. Optics and Lasers in Engineering, 2020, 133: 106114. doi: 10.1016/j.optlaseng.2020.106114 [15] ZHOU Y, WU B X. Experimental study on infrared nanosecond laser-induced backside ablation of sapphire[J]. Journal of Manufacturing Processes, 2010, 12(1): 57-61. doi: 10.1016/j.jmapro.2010.02.002 [16] YIN K, WANG C, DUAN J A, et al. Femtosecond laser-induced periodic surface structural formation on sapphire with nanolayered gold coating[J]. Applied Physics, 2016, A122(9): 1-5. [17] LI Ch Q, WU W L, ZUO H B, et al. Analysis of fracture surface for sapphire cut by long pulse laser[J]. Journal of Synthetic Crystals, 2010, 39(4): 997-1001(in Chinese). [18] ZHAO Z Y, LIU Q J, ZHU Zh Q, et al. First-principles calculation of electronic structure and optical properties of anatase TiO2[J]. Chinese Journal of Semiconductors, 2007, 28(10): 1555-1561(in Chinese). [19] HOSAKA N, SEKIYA T, SATOKO C, et al. Optical properties of single-crystal anatase TiO2[J]. Journal of the Physical Society of Japan, 1997, 66(3): 877-880. doi: 10.1143/JPSJ.66.877 [20] GENG G G, YAO J H, WANG W F, et al. Comparative research on absorption properties of different metal oxides for CO2 laser[J]. A-pplied Laser, 2010, 30(6): 447-450(in Chinese).