Improved construction method of a surface micro-machined pin-jointed actuator-tool using only two mechanical layers.

This paper presents a novel method for surface micro-machining of pin jointed actuators using only two active polySi layers. An alternative sacrificial layer deposition and etching sequence is proposed in order to achieve the linkage construction. The implementation of a four-level profile in the first sacrificial layer is a key factor to significantly reduce topography issues when depositing subsequent layers. Adding to this are some design considerations to further smooth the surface topography irregularities so that a reasonable clearance between the first and second mechanically active layers is obtained. As a result, the need of a planarization process step is foreseen to be avoided. The main advantages of the proposed construction technology are process simplification and standardization conditions in key deposit steps.