Fabrication of Articulated Microarm for Endoscopy by Stacked Microassembly Process (STAMP)

Abstract

Recently it is expected to develop endoscopic tools to grip and lift a target tumor in Endoscopic Submucosal Dissection (ESD). We proposed a new ESD surgery concept in which two wire-driven microarms (1.8 × 1.8 × 22 mm) from the tip of endoscope help lift the tumor to cut. This paper emphasizes a new fabrication method of arm which is fabricated by Stacked Microassembly Process (STAMP). STAMP is a fabrication method of three-dimensional structure by stacking up two-dimensional sheet layers. Generically it is difficult to build a micro-order three-dimensional structure, but we overcame this problem by this method. The microarm was composed of five layers which were fabricated separately using photolithography and electroplating. In the end, individual layers were assembled together and fixed. The microarm used the elastic deformation of metal to bend (Cu or Phosphor Bronze). A strain gauge was attached to the elastic joint as an angle sensor. We calibrated the relation between the angle and output of the strain gauge using image processing program. As the relation was good linearity (R2= 0.9933), we constructed PID feedback control system. Finally, we fabricated a gripper which loaded into the tip of the microarm. The gripper could lift up a piece of meat (2 g).