CILIARY MICROACTUATOR ARRAY FOR SCANNING ELECTRON-MICROSCOPE POSITIONING STAGE

The performance of a ciliary microactuator array as a positioning stag e inside a scanning electron microscope is described. Such arrays are attractive because they can provide micron scale positioning resolutio n with direct electronic control within the sample chamber. The presen t array uses thermal actuation of a polyimide bimorph to produce long- travel deflection of each cilium and electrostatic actuation to provid e a low-power hold-down mode. Each cell in the array consists of four orthogonally oriented cilia which, with proper drive signals, can prod uce object motion along any direction within the plane of the array. A dapting this array for use inside a scanning electron microscope (SEM) requires only a small mounting block and a modest multiconductor feed through. Improved thermal isolation within the vacuum chamber of the S EM drastically reduces the electrical input power requirements over th ose in air, while still allowing full positioning resolution. The addi tion of a gold ground plane coating to the array eliminates charging p roblems by the electron beam and reduces electrical interference from the drive signals. (C) 1998 American Vacuum Society.