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

As cancer becomes the No.1 cause of the death in Japan, endoscopic surgery is gaining attentions. In this paper, endoscopical tool to grip and lift the targeted tumor in ESD (endoscopic submucosal dissection) surgery is proposed. This articulated microarm is part of new ESD surgery concept in which two wire-driven microarms (1times1times25 mm) from the tip of endoscope help lift the tumor to cut. This research needs to emphasize a new fabrication method of arm which is fabricated by photolithography and electroplating. The microarm is composed of five layers. Individual layers are fabricated separately and assembled together in the end. The microarm uses the elastic deformation of metal to bend (Cu or phosphor bronze). It is feedback controlled with PID using a strain gauge attached to the articulated joint. This technique enabled the further miniaturization of the microarm, but it also comes with a downside. It is difficult to build a 3-dimensional structure. We overcome this problem by proposing an assembly method (STAMP: stacking microassembly process). Electroplated layers are assembled by stacking up on top of each other. This assembly process is feasible to produce multiple microarms at one assembly, thus mass-production with low cost is possible. A strain gauge is attached to the elastic joint as an angle sensor.