Polymeric Thermal Microactuator With Embedded Silicon Skeleton: Part II—Fabrication, Characterization, and Application for 2-DOF Microgripper

This paper presents the fabrication, characterization, and application of a novel silicon-polymer laterally stacked electrothermal microactuator. The actuator consists of a deep silicon skeleton structure with a thin-film aluminum heater on top and filled polymer in the trenches among the vertical silicon parts. The fabrication is based on deep reactive ion etching, aluminum sputtering, SU8 filling, and KOH etching. The actuator is 360 mum long, 125 mum wide, and 30 mum thick. It generates a large in-plane forward motion up to 9 mum at a driving voltage of 2.5 V using low power consumption and low operating temperature. A novel 2-D microgripper based on four such forward actuators is introduced. The microgripper jaws can be moved along both the x- and y-axes up to 17 and 11 mum, respectively. The microgripper can grasp a microobject with a diameter from 6 to 40 mum. In addition, the proposed design is suitable for rotation of the clamped object both clockwise and counterclockwise.

[1]  Pasqualina M. Sarro,et al.  Polymer constraint effect for electrothermal bimorph microactuators , 2007 .

[2]  N. Chronis,et al.  Electrothermally activated SU-8 microgripper for single cell manipulation in solution , 2005, Journal of Microelectromechanical Systems.

[3]  Gih-Keong Lau,et al.  Polymeric Thermal Microactuator With Embedded Silicon Skeleton: Part I—Design and Analysis , 2008, Journal of Microelectromechanical Systems.

[4]  Wanjun Wang,et al.  Study on the postbaking process and the effects on UV lithography of high aspect ratio SU-8 microstructures , 2004 .

[5]  H. Fujita,et al.  An electrostatic 2-dimensional micro-gripper for nano structure , 2003, TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664).

[6]  W.J. Li,et al.  Polymer MEMS actuators for underwater micromanipulation , 2004, IEEE/ASME Transactions on Mechatronics.

[7]  R. Feng,et al.  Influence of processing conditions on the thermal and mechanical properties of SU8 negative photoresist coatings , 2002 .

[8]  Pak Kin Wong,et al.  Fabrication process of microsurgical tools for single-cell trapping and intracytoplasmic injection , 2004, Journal of Microelectromechanical Systems.

[9]  P. Sarro,et al.  2D electro-thermal microgrippers with large clamping and rotation motion at low driving voltage , 2007, 2007 IEEE 20th International Conference on Micro Electro Mechanical Systems (MEMS).

[10]  A. Mata,et al.  Fabrication of multi-layer SU-8 microstructures , 2006 .

[11]  J. Wortman,et al.  Young's Modulus, Shear Modulus, and Poisson's Ratio in Silicon and Germanium , 1965 .

[12]  N. Nguyen,et al.  A polymeric microgripper with integrated thermal actuators , 2004 .

[13]  L. Sperling.  Introduction to physical polymer science , 1986 .

[14]  M. Laudon,et al.  Mechanical characterization of a new high-aspect-ratio near UV-photoresist , 1998 .

[15]  Wallace,et al.  Effect of strongly favorable substrate interactions on the thermal properties of ultrathin polymer films. , 1996, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.