单晶硅柱面反射镜离子束倾斜入射加工工艺优化

Process Optimization for Cylindrical Single-Crystal Silicon Mirror with a Tilted Incident Ion Beam Figuring

针对单晶硅柱面镜加工过程中面临的加工效率低、加工精度差以及表面质量难控等问题,提出采用离子束倾斜入射的方法来进行单晶硅柱面镜的加工工艺优化。通过建立离子束倾斜入射的去除函数理论模型,揭示去除效率同入射角度的关联规律;通过分析离子束倾斜入射的微观形貌作用机理,揭示表面质量同入射角度的关联规律;综合优化去除效率和表面质量,获得倾斜入射的最佳入射角度,并建立基于离子束倾斜入射的新工艺路线。在一块尺寸为100 mm×100 mm的单晶硅凸柱面镜上采用新工艺路线进行加工实验,结果表明:在保证加工精度和表面质量的情况下,加工时间节约53.7%,验证了离子束倾斜入射加工的先进性。

In the fabrication of cylindrical single-crystal silicon mirrors,there are many disadvantages,including low removal efficiency,poor figuring accuracy,and difficult surface-quality controllability.Herein,ion-beam figuring(IBF)with a titled incident beam was proposed to optimize the process technology of fabricating cylindrical single-crystal silicon mirrors.First,the theoretical model of the tilted incident IBF removal process was established to determine the relationship between removal efficiency and incident angle.Second,when the ion beam was incident obliquely,the mechanism of the microcosmic morphology was also analyzed to determine the relationship between surface quality and incident angle.Finally,the removal efficiency and surface quality were comprehensively optimized to obtain the optimal incident angle for the tilted incident IBF process,and an innovative process technology based on tilted incident IBF was proposed.A convex cylindrical single-crystal silicon mirror with dimensions of 100 mm×100 mm was tested using the tilted incident IBF process.The total machining time was reduced by 53.7%using the titled incident incident IBF process compared with that using the vertical incident IBF process.Experimental results indicate that the tilted incident IBF process can not only improve the machining efficiency but also obtain high accuracy and quality surface.