Theoretical Analysis and Experiments for the Planarization of Polycrystalline Diamond Film by Eximer Laser

• Main Authors: Chia-Wen Lin, 林嘉文
• Other Authors: Jen-Fin Lin
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/38741683563020671490

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 92 === 　　The polishing by KrF eximer laser for CVD diamond film is researched in the study. Most studies about this topic are the experimental results, so the mechanism of polishing which includes the two parts of graphitization and ablation process is established and confirmed by the experimental results in this study. 　　For the mechanism, the temperature distribution of the diamond film after beamed by laser is derived first, and the critical laser fluence of laser is predicted as 1.9J/cm2 theoretically (and the experimental result is 1.7 J/cm2) according to the highest temperature on the surface. Then, the removing rates under different laser fluence can be predicted after substituting the above critical value. Furthermore, substituting the incubation parameter of the diamond film (about 0.0242 obtained by experiments) into the incubation effect model, we can get the relation between the laser fluence and the number of laser pulses required to ablation. Finally, after substituting the temperature filed by laser beamed into the model of graphitization, the thickness of graphitization can be determined in the range of 39~62nm. 　　For the experiments, there are two parts of polishing and nanoscratch test. The polishing test includes the point and scanning beamed and the removing rates measured experimentally and predicted theoretically are quite close. The change in the surface roughness is observed. The greater laser fluence will damage the surface so the better roughness can be obtained in the case of small laser fluence; and the scanning beamed is more suitable for improvement of roughness. The scratch test is used to obtain the thickness of the residual graphite layer. The values of residual graphite layer thickness is close to those predicted theoretically and the good agreement in the residual graphite layer thickness confirmed the validity of the present model.