Experimental Study On Al₂O₃ And Silicon Wafer By Excimer Laser Micromachining

Excimer lasers have advantages of short wavelength,high repetition frequency,high single pulse energy,and uniform energy.It shows special advantages in the field of high-efficiency micromachining.Therefore,excimer laser micromachining technology has great practical significance.For the role of laser parameters in the excimer laser micromachining process,this dissertation can provide valuable reference.Three typical excimer lasers?193nm ArF excimer laser,248nmKrF excimer laser and308nm XeCl excimer laser?were used to process the Al₂O₃ ceramics and silicon wafers.Through experiments on two materials with three different wavelengths of excimer lasers,the effect of laser energy density,pulse repetition frequency and number of pulses on the micro-via processing of Al₂O₃ ceramics and silicon wafers was studied.Processing law was obtained by micromachining of Al₂O₃ ceramics and processing of silicon wafers.Result of the research indicates:the pulse repetition frequencies of excimer lasers with different wavelengths have no effect on the micro-via processing of Al₂O₃ceramics and silicon wafers.The energy densities of the 193nm,248nm,and 308nm excimer lasers exceed 3.0 J/cm²,9.2J/cm² and 2.8J/cm²,respectively,the microvia width of Al₂O₃ ceramic no longer increases significantly.The energy densities of 193nm,248nm,and 308nm excimer lasers are 6.4J/cm²,6.8J/cm²,and 2.8J/cm²,respectively,the width of the microvia of the silicon wafer does not change afterwards.The effect of the number of laser pulses is that the width of the microvia rapidly increases with the increase in the number of pulses at the beginning,and then the change is gradual.After a certain value is reached,microvia width is no longer associated with the increasing of number of pulses.When the three excimer lasers interact with Al₂O₃ ceramics,the small melt spots and the damage of the small pits indicate that the interaction between the three excimer lasers and Al₂O₃ ceramics is based on the thermal effect mechanism.The193nm excimer laser micromachining silicon wafer has a small heat-affected zone and periodic stripe structure on the surface,they indicate that the processing mechanism is mainly based on the photochemical effect.Region outline clearly described when248nm or 308nm excimer laser interact with silicon,it presents a"cold"processing effect.Cracks and melt zone which appeared at irradiation area.Therefore,the result of248nm or 308nm excimer laser interact with silicon is a combination of photochemical and photothermal effects.Finally,the advantages and deficiencies in the experimental process of this paper are put forward.The next steps need to be analyzed and the future work and experiments are prospected.