Hexsil tweezers for teleoperated micro-assembly

This paper describes essential components of a prototype system for teleoperated microassembly. High aspect ratio molded polysilicon (hexsil) tweezers with integrated in-situ phosphorous doped thermal expansion actuator beams and piezoresistive polysilicon strain gages for tactile feedback are described. The tweezers are normally closed, and require 75 mW to open 35 /spl mu/m. Piezoresistor performance remains to be measured. Metal lines on surface polysilicon flexible electrical interconnects bridge between rotating rigid hexsil beams. Surface polysilicon tweezer tips provide compliance suitable for force-controlled micromanipulation. The task demonstrated is the pick and placement of a 1 /spl mu/m/spl times/4 /spl mu/m/spl times/40 /spl mu/m peg in a 4 /spl mu/m/spl times/4 /spl mu/m hole. The test parts used were surface micromachined SiO/sub 2/ and polysilicon beams held in organized arrays on the silicon wafer by break-away photoresist tethers.