新型MEMS可变光衰减器的微磁执行器

Magnetic Micro Actuator of New Type of MEMS Variable Optical Attenuator

探讨了新型可变光衰减器——光纤横向偏移型MEMS可变光衰减器的微磁驱动方式,从理论上分析了微磁执行器设计时应遵从的原理,讨论和设计了微磁执行器的各个参数,新开发了结合使用正胶(AZ-4000系列)和负胶(SU-8系列)的UV-LIGA工艺:在制作了光纤定位槽的基片上溅射Cr/Cu作为电镀种子层,涂布正胶,紫外光刻得到电镀模具,电镀Cu和FeNi分别得到线圈的下层、中层和上层以及铁芯;在完成下层和中层后,分别进行一次负胶工艺以形成电绝缘层和后续结构的支撑平台,即涂布负胶覆盖较下层结构,光刻开出了通往较上一层的通道并使SU-8聚合、交联以满足性能要求。并运用该工艺实现了微磁执行器。

In this paper,a magnetic micro actuator is presented for new type of MEMS variable optical attenuator,ie:fiberdeflecting type MEMS variable optical attenuator.We theoretically analyzed the principles that should be complied with while designing the magnetic micro actuator,discussed and designed its parameters,and developed a new UVLIGA micromachining process using both positive photoresist(AZ4000 series)and negative photoresist(SU8 series).The process mainly includes sputtering Cr/Cu as electroplate seed layers on the top of substrate with fibers alignment grooves,spinning positive photoresist layers and then patterning the electroplate molds,electroplating Cu or FeNi to form the bottom,middle and top parts of the coil and the magnetic core,respectively,before micromachining every upper level of the device,performing a negative photoresist process to get the electrically insulating and supporting layer,that is,spinning a negative photoresist layer and then patterning to form the conductor vias and to make the photoresist layer crossconnected.Using the process,we realized the magnetic micro actuator.