采用输出功率10 W的355 nm紫外激光器对4层柔性线路板(FPC)进行了盲孔加工实验。分析了紫外激光与铜箔和聚酰亚胺(PI)相互作用的过程和机理,并模拟出在一定条件下紫外激光与聚酰亚胺和铜箔相互作用时的单脉冲刻蚀深度。研究了不同加工方式对加工质量的影响,得到优化工艺参数为:第一次采用加工功率3.9 W,频率80 kHz,第二次将加工功率降到1.4 W,其他参数不变,此时加工盲孔的效果最为理想,重铸层粗糙度为0.88966 μm,孔底粗糙度为1.063 μm。给出了孔底表面的扫描电镜(SEM)图和针式台阶仪测量的盲孔底面三维轮廓及切面二维轮廓图。

A 10 W and 355 nm Nd:YAG laser is used for the blind hole drilling experiment of a 4 layer flexible circuit board (FPC). The interaction mechanism with UV laser and copper and polyimide (PI) is analysised,and the etching depth of single pulse under certain conditions on polyimide and copper is simulated. The effects of the processing methods on the micro-drilling quality are investigated and analyzed. Finally,the optimization of process parameters are obtained,that firstly using the power of 3.9 W,the frequency of 80 kHz,then secondly using the power down to 1.4 W with other parameters unchanged. The recast layer roughness and the bottom surface roughness are 0.88966 μm and 1.063 μm respectively. The scanning electron microscope (SEM) photograph,the 3D profile of bottom surface and the 2D profile of section of the blind hole measured by surface profile measuring system are given.