Precision in-package positioning with a thermal inchworm

This paper describes the design of a thermal inchworm device to realize precision in-package positioning. The inchworm actuation mechanism includes two metallic actuators facing each other and a workpiece between them. Electrothermal actuation is used to move the workpiece in the desired direction by inputting electric currents in a particular sequence. Nickel is chosen as the material of the actuators due to its desirable electrical, thermal and mechanical properties and availability in fabrication facilities. ANSYS theoretical modeling shows the proposed design can achieve high actuation resolution (0.1 μm) with large driving force and will provide power-free latching as well. The transient analysis defines the current input sequence needed to move the workpiece. The design has been carried out for specific application to optical fiber alignment but has potential for a wide range of other applications.