LIGA Process: Steps involved and X-Ray Mask Membrane | Manufacturing Science

In the case of conventional silicon micromachining, the aspect ratio cannot be large because of limitations inherent in etching. Generally, the depth to which machining can be done is limited to a few tens of microns only. This imposes severe constraints for developing three-dimensional microsystems. To produce three-dimensional micro devices with high aspect ratio components, deep etch lithography is necessary. [...]